Semiconductor device and peeling off method and method of manufacturing semiconductor device
10586816 ยท 2020-03-10
Assignee
Inventors
- Toru Takayama (Kanagawa, JP)
- Junya Maruyama (Kanagawa, JP)
- Mayumi Mizukami (Tokyo, JP)
- Shunpei Yamazaki (Tokyo, JP)
Cpc classification
H01L2924/0002
ELECTRICITY
H01L33/44
ELECTRICITY
H01L27/1266
ELECTRICITY
H01L27/1214
ELECTRICITY
H01L27/1248
ELECTRICITY
H01L2924/00
ELECTRICITY
H01L2924/0002
ELECTRICITY
H01L27/1218
ELECTRICITY
G02F1/13613
PHYSICS
H01L29/24
ELECTRICITY
H01L2924/00
ELECTRICITY
H01L29/7869
ELECTRICITY
International classification
H01L27/12
ELECTRICITY
H01L33/44
ELECTRICITY
H01L29/24
ELECTRICITY
H01L29/786
ELECTRICITY
G02F1/136
PHYSICS
H01L21/762
ELECTRICITY
Abstract
The present invention provides a peeling off method without giving damage to the peeled off layer, and aims at being capable of peeling off not only a peeled off layer having a small area but also a peeled off layer having a large area over the entire surface at excellent yield ratio. The metal layer or nitride layer 11 is provided on the substrate, and further, the oxide layer 12 being contact with the foregoing metal layer or nitride layer 11 is provided, and furthermore, if the lamination film formation or the heat processing of 500 C. or more in temperature is carried out, it can be easily and clearly separated in the layer or on the interface with the oxide layer 12 by the physical means.
Claims
1. A manufacturing method of a semiconductor device comprising: forming a first layer over a substrate, the first layer comprising a compound of a metal; forming a second layer over and in contact with the first layer, wherein the second layer has a film stress that is different from a film stress of the first layer; forming an insulating layer over the second layer; forming an element over the second layer with the insulating layer therebetween, the element comprising a transistor; irradiating at least the first layer with a laser beam through the substrate; and separating the substrate and the first layer from the second layer.
2. The manufacturing method of the semiconductor device according to claim 1, wherein the metal is Ti.
3. The manufacturing method of the semiconductor device according to claim 1, wherein the first layer comprises a nitride of the metal.
4. The manufacturing method of the semiconductor device according to claim 1, wherein the second layer comprises an oxide layer.
5. The manufacturing method of the semiconductor device according to claim 1, wherein the element further comprises a light emitting element.
6. The manufacturing method of the semiconductor device according to claim 1, wherein the laser beam is a linear laser beam.
7. The manufacturing method of the semiconductor device according to claim 1, wherein the substrate has a transparency.
8. A manufacturing method of a semiconductor device comprising: forming a first layer over a substrate, the first layer comprising a metal; forming a second layer over and in contact with the first layer; forming an insulating layer over the second layer; forming an element over the second layer with the insulating layer therebetween, the element comprising a transistor; irradiating at least the first layer with a laser beam through the substrate; and separating the element from the first layer.
9. The manufacturing method of the semiconductor device according to claim 8, wherein the first layer comprises a compound comprising the metal.
10. The manufacturing method of the semiconductor device according to claim 8, wherein the metal is Ti.
11. The manufacturing method of the semiconductor device according to claim 8, wherein the first layer comprises a nitride of the metal.
12. The manufacturing method of the semiconductor device according to claim 8, wherein the element further comprises a light emitting element.
13. The manufacturing method of the semiconductor device according to claim 8, wherein the laser beam is a linear laser beam.
14. The manufacturing method of the semiconductor device according to claim 8, wherein the substrate has a transparency.
15. A manufacturing method of a semiconductor device comprising: forming a first layer over a substrate, the first layer comprising a compound of a metal; forming a second layer over and in contact with the first layer, wherein the second layer has a film stress that is different from a film stress of the first layer; forming an insulating layer over the second layer; forming an element over the second layer with the insulating layer therebetween, the element comprising a transistor; irradiating at least the first layer with a laser beam through the substrate; separating the substrate and the first layer from the second layer; and attaching a plastic film to the second layer after separating the substrate and the first layer.
16. The manufacturing method of the semiconductor device according to claim 15, wherein the metal is Ti.
17. The manufacturing method of the semiconductor device according to claim 15, wherein the first layer comprises a nitride of the metal.
18. The manufacturing method of the semiconductor device according to claim 15, wherein the second layer comprises an oxide layer.
19. The manufacturing method of the semiconductor device according to claim 15, wherein the element further comprises a light emitting element.
20. The manufacturing method of the semiconductor device according to claim 15, wherein the laser beam is a linear laser beam.
21. The manufacturing method of the semiconductor device according to claim 15, wherein the substrate has a transparency.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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DESCRIPTION OF THE PREFERRED EMBODIMENTS
(24) Hereinafter, embodiments of the present invention will be described.
Embodiment 1
(25) Hereinafter, a representative peeling off procedure utilizing the present invention will be schematically shown with reference to
(26) In
(27) In
(28) First, as shown in
(29) Subsequently, a peeled off layer 13 is formed on the oxide layer 12 (
(30) Subsequently, the substrate 10 on which the nitride layer or metal layer 11 is provided is pulled away by the physical means (
(31) Moreover, the present invention can be applied to a method of preparing a variety of semiconductor devices. Particularly, it can be made light by using plastic substrate for a transferring body and supporting body. In the case where a liquid crystal display device is prepared, the supporting body is made as an opposing substrate, the supporting body may be adhered to the peeled layer by utilizing a seal member as an adhesive member. In this case, an element provided on the foregoing peeled layer has a pixel electrode, and it is made so that a liquid crystal material is packed between the relevant pixel electrode and the foregoing opposing substrate. Moreover, the order of the processes for the preparation of a liquid crystal display device is not particularly limited, and an opposing substrate as a supporting body was pasted. After the liquid crystal was implanted, the substrate may be peeled off and pasted on a plastic substrate as a transferring body, or after the pixel electrode was formed, the substrate may be peeled off, after the plastic substrate as the first transferring body was pasted, the opposing substrate as the second transferring body may be pasted.
(32) Moreover, in the case where a light emitting device represented by a light emitting device having an OLED is prepared, it is preferable that the supporting body is made as a sealing medium, a light emitting element is completely interrupted from the exterior so as to prevent substances such as water content, oxygen or the like which promotes the deterioration of an organic compound layer from penetrating from the exterior. Moreover, in the case where a light emitting device represented by a light emitting device having an OLED is prepared, it is preferable that substances such as water, oxygen or the like promoting the deterioration of the organic compound layer is sufficiently prevented from penetrating from the exterior not only into the supporting body but also the transferring body. Moreover, the order of the processes for the preparation of a light emitting device is not particularly limited.
(33) After a light emitting element was formed, a plastic substrate as a supporting body may be pasted, the substrate may be peeled off, and the plastic substrate as a transferring body may be pasted, or after a light emitting element was formed, the substrate may be peeled off, and after the plastic substrate as the first transferring body was pasted, the plastic substrate as the second transferring body may be pasted.
Embodiment 2
(34) As for the present Embodiment, the peeling off procedure for peeling off the substrate while the impurities diffusion from the nitride layer or metal layer and the substrate is prevented by providing a primary coat insulating layer being in contact with the peeled off layer is schematically shown in
(35) First, as shown in
(36) In the present invention, it is important that the film stress of this oxide layer 22 and the film stress of the nitride layer or metal layer 21 are made different. The respective film thickness is appropriately set in the range from 1 nm to 1000 nm, and the respective film stress may be adjusted. Moreover,
(37) Subsequently, a primary coat insulating layers 23a and 23b were formed on the oxide layer 22 by plasma CVD method. Here, the silicon oxynitride film 23a (composition ratio Si=32%, O=27%, N=24% and H=17%) prepared from the raw material gases SiH.sub.4, NH.sub.3, and N.sub.2O was formed (preferably, 10-200 nm) in thickness of 50 nm at 400 C. of the film formation temperature by a plasma CVD method, and further the silicon oxynitride film 23b (composition ratio Si=32%, O=59%, N=7% and H=2%) prepared from the raw material gases SiH.sub.4 and N.sub.2O was lamination-formed (preferably, 50-200 nm) in thickness of 100 nm at 400 C. of the film formation temperature by a plasma CVD method. But it is not particularly limited, and a monolayer or a lamination having three layers or more may be used. Subsequently, a peeled off layer 24 is formed on the primary coat insulating layer 23b (
(38) Moreover, in the case where the concave and convex are formed on the surface due to the nitride layer or metal layer 21 and the oxide layer 22, the surface may be flattened before and after the primary coat insulating layer is formed. The coverage on the peeled off layer 24 becomes more excellent when it is flattened, in the case where the peeled off layer 24 containing an element is formed, it is preferable since the element characteristics become easily stable. It should be noted that as a flattening processing, an etch back method in which an etching or the like is performed after the formation of the coated film (resist film or the like), a chemical mechanical polishing method (CMP method) or the like may be used.
(39) Subsequently, the substrate 20 on which the nitride layer or metal layer 21 is provided is pulled away by the physical means (
(40) In this way, the peeled off layer 24 formed on the primary coat insulating layer 22 can be separated from the substrate 20. The state after it was peeled off is shown in
(41) Moreover, after it was peeled off, the peeled off layer 24 pulled away may be pasted on the transferring body (not shown).
(42) Moreover, the present invention can be applied to a method of preparing a variety of semiconductor devices. Particularly, it can be made light by using plastic substrate for a transferring body and supporting body. In the case where a liquid crystal display device is prepared, the supporting body is made as an opposing substrate, the supporting body may be adhered to the peeled layer by utilizing an sealing medium as an adhesive member. In this case, an element provided on the peeled layer has a pixel electrode, and it is made so that a liquid crystal material is packed between the relevant pixel electrode and the foregoing opposing substrate. Moreover, the order of the processes for the production of a liquid crystal display device is not particularly limited, an opposing substrate as a supporting body was pasted, after the liquid crystal was implanted, and the substrate may be peeled off and pasted on a plastic substrate as a transferring body, or after the pixel electrode was formed, the substrate may be peeled off. After the plastic substrate as the first transferring body was pasted, the opposing substrate as the second transferring body may be pasted.
(43) Moreover, in the case where a light-emitting device represented by a light emitting device having an OLED is prepared, it is preferable that the supporting body is made as a sealing medium, a light emitting element is completely interrupted from the exterior so as to prevent substances such as water content, oxygen or the like which promotes the deterioration of an organic compound layer from penetrating from the exterior. Moreover, in the case where a light-emitting device represented by a light emitting device having an OLED is prepared, it is preferable that substances such as water content, oxygen or the like promoting the deterioration of the organic compound layer is sufficiently prevented from penetrating from the exterior not only into the supporting body but also the transferring body. Moreover, the order of the processes for the preparation of a light emitting device is not particularly limited, after a light emitting element was formed, a plastic substrate as a supporting body may be pasted, the substrate may be peeled off, and the plastic substrate as a transferring body may be pasted, or after a light emitting element was formed, the substrate may be peeled off, and after the plastic substrate as the first transferring body was pasted, the plastic substrate as the second transferring body may be pasted.
Embodiment 3
(44) In the present embodiment, in addition to Embodiment 1, an example in which the irradiation of laser beam or the heat processing is performed in order to promote the peeling off is shown in
(45) In
(46) Since the step of forming it until the peeled off layer 43 is made is the same with Embodiment 1, the description is omitted.
(47) After the peeled off layer 43 was formed, the irradiation of laser beam is performed (
(48) Moreover, it is desirable that a material used for the nitride layer or metal layer 41 is a material easily absorbing the laser beam, and titanium nitride is preferred. It should be noted that in order to make the laser beam pass, a substrate having a transparency is used for the substrate 40.
(49) Subsequently, the substrate 40 on which the nitride layer Or metal layer 41 is provided is pulled away by the physical means (
(50) The film stresses can be changed each other and the peeling can be promoted by irradiating the laser beam and heating the interface between the nitride layer or metal layer 41 and the oxide layer 42, and the peeling off can be performed by smaller force. Moreover, although here, one example in which it is supposed that the peeled off layer 43 has a sufficient mechanical strength is shown, in the case where the mechanical strength of the peeled off layer 43 is not sufficient, it is preferred that after the supporting body (not shown) for fixing the peeled off layer 43 was pasted, it is peeled off. In this way, the peeled off layer 43 formed on the oxide layer 42 can be separated from the substrate 40. The state after it was peeled off is shown in
(51) Moreover, instead of laser beam, the heat processing in an electric furnace may be available.
(52) Moreover, before the supporting body is adhered, or before it is peeled off by the foregoing physical means, the heating processing or the irradiation of laser beam may be performed.
(53) Furthermore, the present Embodiment can be combined with Embodiment 2.
Embodiment 4
(54) In the present embodiment, in addition to Embodiment 1, an example in which an oxide in a granular shape is provided on the interface between the nitride layer or metal layer and the oxide layer in order to promote the peeling off is shown in
(55) In
(56) Since the step of forming it until the nitride layer or metal layer 51 is formed is the same with Embodiment 1, the description is omitted.
(57) After the nitride layer or metal layer 51 was formed, the oxide in a granular shape 52a is formed. As the oxide in a granular shape 52a, a metal oxide material, form example, ITO (indium oxide-tin oxide alloy), indium oxide-zinc oxide alloy (In.sub.2O.sub.3ZnO), zinc oxide (ZnO) or the like may be used.
(58) Subsequently, the oxide layer 52b for covering the oxide layer 52a in a granular shape is formed. As the oxide layer 52b, one representative example may use silicon oxide, oxynitride silicon, and metal oxide materials. It should be noted that any film formation method such as a sputtering method, a plasma CVD method, coating method or the like might be applied to the oxide layer 23b.
(59) Subsequently, a peeled off layer 53 is formed on the oxide layer 52b (
(60) Subsequently, the substrate 50 on which the nitride layer or metal layer 51 is provided is pulled away by the physical means (
(61) The bonding force between the nitride layer or metal layer 51 and the oxide layer 52 is weakened, the adhesiveness from each other is changed, the peeling off can be promoted by providing the oxide in a granular shape 52b and these can be peeled off by smaller force. Moreover, although here, an example in which it is supposed that the peeled off layer 53 has a sufficient mechanical strength is shown, in the case where the mechanical strength of the peeled off layer 53 is not sufficient, it is preferred that after the supporting body (not shown) for fixing the peeled off layer 53 was pasted, it is peeled off.
(62) In this way, the peeled off layer 53 formed on the oxide layer 52b can be separated from the substrate 50. The state after it was peeled off is shown in
(63) The present invention comprising the above-described constitutions will be described in detail with reference to Examples shown below.
EXAMPLES
Example 1
(64) Examples of the present invent ion will be described with reference to
(65) First, the nitride layer or metal layer 101, the oxide layer 102 and the primary coat insulating film 103 are formed on the substrate 100, after a semiconductor film having a crystal structure was obtained, a semiconductor layers 104-108 isolated in a island shape are formed by etching processing in the desired shape.
(66) As the substrate 100, the glass substrate (#1737) is used.
(67) Moreover, as the metal layer 101, an element selected from Ti, Al, Ta, W, Mo, Cu, Cr, Nd, Fe, Ni, Co, Zr, Zn, Ru, Rh, Pd, Os, Ir and Pt, or a monolayer consisted of alloy materials or compound materials whose principal components are the foregoing elements or a lamination of these may be used. More preferably, a monolayer consisted of these nitrides, for example, titanium nitride, tungsten nitride, tantalum nitride, molybdenum nitride or a lamination of these may be used. Here, titanium nitride film having film thickness of 100 nm is utilized by a sputtering method.
(68) Moreover, as the oxide layer 102, a monolayer consisted of a silicon oxide material or a metal oxide material, or a lamination of these may be used. Here, a silicon oxide film having film thickness of 200 nm is used by a sputtering method. The bonding force between the metal layer 101 and the oxide layer 102 is strong in heat processing, the film peeling (also referred to as solely peeling) or the like does not occur. However, it can be easily peeled off on the inside of the oxide layer or on the interface by the physical means.
(69) Subsequently, as a primary coat insulating layer, a silicon oxynitride film 103a (composition ratio Si=32%, O=27%, N=24% and H=17%) prepared from the raw material gases SiH.sub.4, NH.sub.3, and N.sub.2O was formed (preferably, 10-200 nm) in thickness of 50 nm at 400 C. of the film formation temperature by a plasma CVD method. Subsequently, after the surface was washed by ozone water, the oxide film of the surface was removed by dilute hydrofluoric acid (1:100 dilution). Subsequently, a silicon oxynitride film 103b (composition ratio Si=32%, O=59%, N=7% and H=2%) prepared from the raw material gases SiH.sub.4 and N.sub.2O was lamination-formed (preferably, 50-200 nm) in thickness of 100 nm at 400 C. of the film formation temperature by a plasma CVD method, and further, a semiconductor layer (here, an amorphous silicon layer) having an amorphous structure was formed (preferably, 25-80 nm) in thickness of 54 nm at 300 C. of the film formation temperature without the air release by a plasma CVD method.
(70) In the present Example, although the primary coat film 103 is shown as a two-layer structure, a monolayer film of the foregoing insulating film or a layer as a structure in which two layers or more are laminated may be formed. Moreover, there are no limitations to materials for a semiconductor film, but preferably, it may be formed using a silicon or a silicon germanium (Si.sub.xGe.sub.1-x (X=0.0001-0.02)) alloy or the like by the known means (sputtering method, LPCVD method, plasma CVD method or the like). Moreover, a plasma CVD apparatus may be sheet type apparatus, or batch type apparatus. Moreover, the primary insulating film and the semiconductor film may be continuously formed in the same film formation chamber without contacting with the air.
(71) Subsequently, after the surface of the semiconductor film having an amorphous structure was washed, an oxide film having an extremely thin thickness of about 2 nm is formed on the surface with ozone water. Subsequently, in order to control the threshold value of TFT, a doping of a trace of impurity element (boron or phosphorus) is performed. Here, boron was added to the amorphous silicon film under the doping conditions of 15 kV of acceleration voltage, 30 sccm of flow rate of the gas in which diborane was diluted into 1% with hydrogen, 210.sup.12/cm.sup.2 of dosage without mass segregating diborane (B.sub.2H.sub.6) by utilizing an ion doping method in which plasma excitation was performed.
(72) Subsequently, nickel acetate solution containing 10 ppm of nickel when it is converted to weight was coated by a spinner. A method of spreading over the entire surface with nickel element by a sputtering method instead of coating may be employed.
(73) Subsequently, a semiconductor film having a crystal structure was formed by performing the heat processing and crystallizing it. For this heat processing, the heat processing of an electric furnace or the irradiation of strong light may be used. In the case where it is performed by utilizing the heat processing of the electric furnace, it may be performed at 500 C.-650 C. for 4-24 hours. Here, after the heat processing (500 C., one hour) for dehydrogenation was carried out, a silicon film having a crystal structure was obtained by performing the heat processing for crystallization (550 C., 4 hours). It should be noted that although here, crystallization was performed using the heat processing by the furnace, however, the crystallization may be performed by a lamp anneal apparatus.
(74) It should be noted that here, a crystallization technology using nickel as a metal element for promoting the crystallization of silicon is used. However, the other known crystallization technology, for example, solid phase crystallization method or laser crystallization method may be used.
(75) Subsequently, after the oxide film of the surface of the silicon film having a crystal structure was removed by dilute hydrofluoric acid or the like, the irradiation of the first laser beam (XeCl: wavelength 308 nm) for enhancing the crystallization ratio and repairing the defaults remained within the crystal grain is performed in the air, or in the oxygen atmosphere. For a laser beam, an excimer laser beam of 400 nm or less of wavelength, the second higher harmonic wave, the third higher harmonic wave of YAG laser are used. Anyhow, using pulse laser beam having about 10-1000 Hz of repeated frequency, the relevant laser beam is condensed at 100-500 mJ/cm.sup.2 by an optical system, irradiated with overlap ratio of 90-95% and it may be made it scan the surface of the silicon film. Here, the irradiation of the first laser beam is performed at repeated frequency of 30 Hz, 393 mJ/cm.sup.2 of energy density in the air. It should be noted that since it is performed in the air, or in the oxygen atmosphere, an oxide film is formed on the surface by the irradiation of the first laser beam.
(76) Subsequently, after the oxide film formed by irradiation of the first laser beam was removed by dilute hydrofluoric acid, the irradiation of the second laser beam is performed in the nitrogen atmosphere or in the vacuum, thereby flattening the surface of the semiconductor film. For this laser beam (second laser beam), an excimer laser beam having a wavelength of 400 nm or less, the second higher harmonic wave, the third higher harmonic wave of YAG laser are used. The energy density of the second laser beam is made larger than the energy density of the first laser beam, preferably, made larger by 30-60 mJ/cm.sup.2. Here, the irradiation of the second laser beam is performed at 30 Hz of the repeated frequency and 453 mJ/cm.sup.2 of energy density, P-V value (Peak to Valley, difference between the maximum value and minimum value) of the concave and convex in the surface of the semiconductor film is to be 50 nm or less. This P-V value is obtained by an AFM (atomic force microscope). Moreover, in the present Example, the irradiation of the second laser beam was performed on the entire surface. However, since the reduction of the OFF-state current is particularly effective to the TFT of the pixel section, it may be made a step of selectively irradiating only on at least pixel section.
(77) Subsequently, a barrier layer consisted of an oxide film of total 1-5 nm in thickness is formed by processing the surface with ozone water for 120 seconds.
(78) Subsequently, an amorphous silicon film containing argon element which is to be gettering site is formed in film thickness of 150 nm on the barrier layer by a sputtering method. The film formation conditions by a sputtering method of the present Example are made as 0.3 Pa of film formation pressure, 50 (sccm) of gas (Ar) volumetric flow rate, 3 kW of film formation power, and 150 C. of the substrate temperature. It should be noted that the atomic percentage of argon element contained in the amorphous silicon film under the above-described conditions is in the range from 310.sup.20/cm.sup.3 to 610.sup.20/cm.sup.3, the atomic percentage of oxygen is in the range from 110.sup.19/cm.sup.3 to 310.sup.19/cm.sup.3. Then, the gettering is performed by carrying out the heat processing at 650 C. for 3 minutes using a lamp anneal apparatus.
(79) Subsequently, after the barrier layer is made an etching stopper, the amorphous silicon film containing argon element which is the gettering site was selectively removed, the barrier layer is selectively removed with dilute hydrofluoric acid. It should be noted that since when gettering, nickel tends to easily move into the higher oxygen density region, it is desirable that the barrier layer consisted of an oxide film is removed after the gettering.
(80) Subsequently, after a thin oxide film is formed with the ozone water on the surface of the silicon film (also referred to as polysilicon film) having the obtained crystal structure, a mask consisted of a resist is formed, and the semiconductor layers 104-108 isolated in an island shape is formed in the desired shape by etching processing. After the semiconductor layer was formed, the mask consisted of the resist is removed.
(81) Subsequently, the oxide film was removed by an etchant containing hydrofluoric acid, and at the same time, the surface of the silicon film was washed, an insulating film whose principal component is silicon and which is to be agate insulating film 109 is formed. In the present Example, a silicon oxynitride film (composition ratio Si=32%, O=59%, N=7% and H=2%) is formed in thickness of 115 nm by plasma CVD method.
(82) Subsequently, as shown in
(83) As an electrically conductive material for forming the first electrically conductive film and the second electrically conductive film, it is formed using an element selected from Ta, W, Ti, Mo, Al and Cu, or alloy material or compound material whose principal component is the foregoing element. Moreover, as the first electrically conductive film and the second electrically conductive film, a semiconductor film represented by a polycrystal silicon film in which impurity element such as phosphorus or the like is doped, and Ag, Pd, Cu alloys may be used. Moreover, it is not limited to a two-layer structure. For example, it may be made a three-layer structure in which a tungsten film having film thickness of 50 nm, aluminum-silicon (AlSi) alloy having film thickness of 500 nm, and a titanium nitride film having film thickness of 30 nm are in turn laminated. Moreover, in the case of a three-layer structure, instead of tungsten of the first electrically conductive film, tungsten nitride may be used, instead of aluminum-silicon (AlSi) alloy of the second electrically conductive film, aluminum-titanium (AlTi) alloy film may be used, or instead of a titanium nitride film of the third electrically conductive film, a titanium film may be used. Moreover, it may be a monolayer structure.
(84) Next, as shown in
(85) In the present Example, also to the substrate side (sample stage), 150 W of RF (13.56 MHz) electric power is turned on, substantially negative self-bias voltage is applied. It should be noted that the size of the electrode area on the side of the substrate is 12.5 cm12.5 cm, and the size of the coil type electrode area (here, quartz disk on which the coil is provided) is an area of a disk having a diameter of 25 cm. The end section of the first electrically conductive layer is made in a tapered shape by etching W film under the first etching conditions. The etching rate to W under the first etching conditions is 200.39 nm/min, the etching rate to TaN is 80.32 nm/min, and the selection ratio of W to TaN is about 2.5. Moreover, the tapered angle of W is about 26. Then, the second etching conditions were changed without removing the masks 112-117 consisted of resists, CF.sub.4 and Cl.sub.2 were used for etching gas, the respective ratio of gas volumetric flow rate was made 30/30 (sccm), 500 W of RF (13.56 MHz) electric power was turned on to the coil type electrode at 1 Pa of the pressure, the plasma was generated and the etching was performed for about 30 seconds. 20 W of RF (13.56 MHz) electric power was also turned on to the side of the electrode (sample stage), and substantially a negative self bias voltage was applied. The etching rate to W under the second etching conditions was 58.97 nm/min, and the etching rate to TaN was 66.43 nm/min. It should be noted that in order to etch without remaining residue on the gate insulating film, it might increase the etching time at the ratio of about 10-20%. In the above-described first etching processing, the end section of the first electrically conductive layer and the second electrically conductive layer becomes in a tapered shape due to the effect of the bias voltage to be applied to the substrate side by making the mask consisted of a resist adjust to be suitable. The angle of this tapered section may be made in the range from 15 to 45.
(86) In this way, electrically conductive layers 119-123 in the first shape consisted of the first electrically conductive layer and the second electrically conductive layer (first electrically conductive layers 119a-124a and the second electrically conductive layers 119b-124b) are formed by the first etching processing. The insulating film 109 which is to be a gate insulating film is etched about 10-20 nm, becomes a gate insulating film 118 whose region not covered with the electrically conductive layers in the first shape 119-123 is made thinner.
(87) Subsequently, the second etching processing is performed without removing the mask consisted of the resist. Here, using SF.sub.6, Cl.sub.2 and O.sub.2 for etching gas, the etching was performed for 25 seconds by making the ratio of gas volumetric flow rate 24/12/24 (sccm), turning on 700 W of RF (13.56 MHz) electric power to the coil type electrode and generating the plasma at 1.3 Pa of the pressure. 10 W of RF (13.56 MHz) electric power was also turned on to the side of the electrode (sample stage), and substantially a negative self bias voltage was applied. The etching rate to W under the second etching conditions was 227.3 nm/min, and the etching rate to TaN was 32.1 nm/min, the selection ratio of W to TaN is 7.1, the etching rate to SiON which is an insulating film 118 is 33.7 nm/min, and the selection ratio of W to SiON is 6.83. In this way, in the case where SF.sub.6 is used for etching gas, since the selection ratio to the insulating film 118 is high, the film reduction can be suppressed. In the present Example, in the insulating film 118, only about 8 nm of the film reduction occurred. The tapered angle became 70 by the second etching processing. The second electrically conductive layers 126b-131b are formed by the second etching processing. On the other hand, the first electrically conductive layer is scarcely etched, and becomes the first electrically conductive layers 126a-131a. It should be noted that the sizes of the first electrically conductive layers 126a-131a are almost the same with the first electrically conductive layers 119a-124a. Actually, although there are some cases where the width of the first electrically conductive layer is backward by about 0.3 m comparing to that before the second etching, that is, about 0.6 m in whole line width backward, there is scarcely no change in size.
(88) Moreover, in the case where instead of two-layer structure, three-structure in which a tungsten film having film thickness of 50 nm, an aluminum-silicon (AlSi) alloy film having film thickness of 500 nm, and a titanium nitride film are in turn laminated is employed, as for the first etching conditions of the first etching processing, the etching may be performed for 117 seconds by utilizing BCl.sub.3, Cl.sub.2 and O.sub.2 as raw material gases, making the respective ratio of gas volumetric flow rates 65/10/5 (sccm), turning on 300 W of RF (13.56 MHz) electric power to the substrate side (sample stage), turning on 450 W of RF (13.56 MHz) electric power to the coil type electrode at 1.2 Pa of the pressure and generating plasma, as for the second etching conditions of the first etching processing, the etching may be performed for about 30 seconds by utilizing CF.sub.4, Cl.sub.2 and O.sub.2 as raw material gases, making the respective ratio of gas volumetric flow rates 25/25/10 (sccm), turning on 20 W of RF (13.56 MHz) electric power to the substrate side (sample stage), turning on 500 W of RF (13.56 MHz) electric power to the coil type electrode at 1 Pa of the pressure and generating a plasma, as for the second etching processing, the etching may be performed by utilizing BCl.sub.3 and Cl.sub.2 as raw material gases, making the respective ratio of gas volumetric flow rates 20/60 (sccm), turning on 100 W of RF (13.56 MHz) electric power to the substrate side (sample stage), turning on 600 W of RF (13.56 MHz) electric power to the coil type electrode at 1.2 Pa of the pressure and generating a plasma.
(89) Subsequently, after the mask consisted of the resist was removed, the state of
(90) It should be noted that in the present Example, after the mask consisted of resist was removed, the first doping processing was performed. However, the first doping processing may be performed without removing the mask consisted of the resist.
(91) Subsequently, as shown in
(92) The conditions for ion doping in the second doping processing are 1.510.sup.15 atoms/cm.sup.2 of dosage, and 60-100 keV of the acceleration voltage, and under these conditions, phosphorus (P) is doped. Here, by utilizing the second electrically conductive layers 126b-128b as masks, the impurity region is formed in a self-aligned manner on the respective semiconductor layers. Needless to say, to the region covered with the masks 137-139, the impurities are not added. Thus, the second impurity regions 140-142 and the third impurity region 144 are formed. The impurity element conferring n-type is added in the density range from 110.sup.20 to 110.sup.21/cm.sup.3 on the second impurity regions 140-142. Here, the region having the same density range with the second impurity region is also referred to as n+ region.
(93) Moreover, the third impurity region is formed in a lower density than that of the second impurity region by the first electrically conductive layer, the impurity element conferring n-type is added in the density range from 110.sup.15 to 110.sup.19/cm.sup.3. It should be noted that as for the third impurity region, since the doping is performed by making it pass the portion of the first electrically conductive layer and performing the doping, it has a density gradient in which the impurity density increases toward the end section of the tapered section. Here, the region having the same density range with the third impurity region is also referred to as n-region. Moreover, the impurity element is not added to the region covered by the masks 138 and 139 by the second doping processing, therefore, these become the first impurity regions 145 and 146.
(94) Subsequently, after the masks 137-139 consisted of the resists were removed, the masks 148-150 consisted of resists are newly formed, and as shown in
(95) In the drive circuit, the fourth impurity regions 151, 152 and the fifth impurity regions 153, 154 in which the impurity element conferring p-type electrically conductive type to the semiconductor layer for forming p-channel type TFT and the semiconductor layer for forming retention volume has been added are formed by the above-described third doping processing.
(96) Moreover, it is made so that the impurity element conferring p-type is added to the fourth impurity regions 151,152 in the range from 110.sup.20 to 110.sup.21/cm.sup.3. It should be noted that the fourth impurity regions 151,152 are the regions (n-region) to which phosphorus (P) has been added in the prior step, but its 1.5- to 3-fold density of impurity element conferring p-type is added, and the electrically conductive type is p-type. Here, the region having the same density region with the fourth impurity region is also referred to as p+ region.
(97) Moreover, the fifth impurity regions 153, 154 are formed on the region overlapped with the tapered section of the second electrically conductive layer 127a, it is made so that the impurity element conferring p-type is added in the density range from 110.sup.18 to 110.sup.28/cm.sup.3. Here, the region having the same density range with the fifth impurity region is also referred to as p-region.
(98) Up to the above-described steps, the impurity regions having n-type or p-type electrically conductive type are formed on the respective semiconductor layers. The electrically conductive layers 126-129 become gate electrodes of TFT. Moreover, the electrically conductive layer 130 becomes one of the electrodes for forming the retention volume in the pixel section. Furthermore, the electrically conductive layer 131 forms source wirings in the pixel section.
(99) Subsequently, an insulating film (not shown) for covering the nearly whole surface is formed. In the present Example, a silicon oxide film having film thickness of 50 nm has been formed by plasma CVD method. Needless to say, this insulating film is not limited to the silicon oxide film, another insulating film containing silicon may be used as a monolayer or a lamination structure.
(100) Subsequently, the step for processing the activation of the impurity elements added to the respective semiconductor layers is carried out. This activation step is performed by rapid thermal annealing method (RTA method) using a lamp light source, or a method of irradiating YAG laser or excimer laser from the back side, or heat processing using a furnace, or a method combined with any method of these methods.
(101) Moreover, in the present Example, although an example in which an insulating film was formed before the above-described activation has been shown, the step may be made a step in which after the above-described activation was performed, the insulating film is formed. Subsequently, the first interlayer insulating film 155 consisted of a silicon nitride film is formed, the heat processing (heat processing at 300-550 C. for 1-12 hours) is performed, and the step in which a semiconductor layer is hydrogenated (
(102) Subsequently, the second interlayer insulating film 156 consisted of organic insulating material is formed on the first interlayer insulating film 155. In the present Example, an acryl resin film having film thickness of 1.6 m is formed. Subsequently, a contact hole reaching the source wiring 131, a contact hole reaching the electrically conductive layers 129, 130 and a contact hole reaching the respective impurity regions are formed. In the present Example, several etching processes are in turn performed. In the present Example, after the second interlayer insulating film was etched by utilizing the first interlayer insulating film as an etching stopper, the insulating film (not shown) was etched following the first interlayer insulating film was etched by utilizing the insulating film (not shown). Then, the wirings and pixel electrodes are formed using Al, Ti, Mo, W and the like. It is preferable that as for these materials for electrode and pixel electrode, a film whose principal component is Al or Ag, or a material excellent in reflecting properties such as a lamination of these or the like is used. Thus, source electrodes or drain electrodes 157-162, a gate wiring 164, a connecting wiring 163, and a pixel electrode 165 are formed.
(103) As described above, a drive circuit 206 having a n-channel type TFT 201, a p-type channel type TFT 202 and a n-type channel type TFT 203, and a pixel section 207 having a pixel TFT 204 consisted of a n-channel type TFT and a retention volume 205 can be formed on the same substrate (
(104) On the pixel section 207, the pixel TFT 204 (n-channel type TFT) has a channel formation region 169, the first impurity region (n-region) 147 formed outside of the electrically conductive layer 129 forming a gate electrode, and the second impurity regions (n+ region) 142, 171 functioning as a source region or drain region. Moreover, the fourth impurity region 152, the fifth impurity region 154 are formed on the semiconductor layer functioning as one of the electrode of the retention volume 205. The retention volume 205 is formed with the second electrode 130 and the semiconductor layers 152, 154 and 170 by utilizing the insulating film (same film with gate insulating film) as a dielectric.
(105) Moreover, in the drive circuit 206, the n-channel type TFT 201 (first n-channel type TFT) has a channel formation region 166, the third impurity region (n-region) 144 overlapped with one portion of the electrically conductive layer 126 which forms a gate electrode via an insulating film, and the second impurity region (n+ region) 140 functioning as a source region or drain region.
(106) Moreover, in the drive circuit 206, the p-channel type TFT 202 has a channel formation region 167, the fifth impurity region (p-region) 153 overlapped with one portion of the electrically conductive layer 127 which forms a gate electrode via an insulating film, and the fourth impurity region (p+ region) 151 functioning as a source region or drain region.
(107) Moreover, in the drive circuit 206, the n-channel type TFT 203 (second n-channel type TFT) has a channel formation region 168, the first impurity region (n-region) 146 outside of the electrically conductive layer 128 which forms a gate electrode, and the second impurity region (n+ region) 141 functioning as a source region or drain region.
(108) A shift register circuit, a buffer circuit, a level shifter circuit, a latch circuit and the like are formed by appropriately combining these TFTs 201-203, and the drive circuit 206 may be formed. For example, a CMOS circuit may be formed by complementarily connecting the n-channel type TFT 201 and a p-channel type TFT 202. Particularly, for a buffer circuit whose drive voltage is high, for the purpose of preventing the deterioration due to the hot carrier effect, the structure of a n-channel type TFT 203 is suitable.
(109) Moreover, for a circuit that the reliability is considered as the top priority, the structure of a n-channel type TFT 201 which is a GOLD structure is suitable.
(110) Moreover, since the reliability can be enhanced by enhancing the flattening of the surface of a semiconductor film, in a TFT having a GOLD structure, a sufficient reliability can be obtained also by diminishing the area of the impurity region overlapping with a gate electrode via a gate insulating film. Concretely, in a TFT having a GOLD structure, a sufficient reliability can be obtained by diminishing the size of the portion which is a tapered section of a gate electrode. Moreover, in a TFT having a GOLD structure, when the gate insulating film is thinner, the parasitic capacitance increases. However, the size of the portion which is a tapered section of the gate electrode (first electrically conductive layer) is made smaller, and the parasitic capacitance is reduced, f characteristic (frequency characteristic) is also enhanced and further a high operation is possible and the TFT obtained a sufficient reliability.
(111) It should be noted that also in the pixel TFT of the pixel section 207, the reduction of OFF-state current and the reduction of the variation are realized by irradiation of the second laser beam.
(112) Moreover, in the present Example, an example in which an active matrix substrate for forming a reflective type display device is prepared is shown, but when the pixel electrode is formed by a transparent electrically conductive film, although the number of photo-masks increases by one sheet, a transparent type display device can be formed.
(113) Moreover, in the present Example, a glass substrate was used, but it is not particularly limited. A quartz substrate, a semiconductor substrate, a ceramic substrate, and a metal substrate can be used.
(114) Moreover, after the state of
Example 2
(115) In the present Example, the step in which an active matrix type liquid crystal display device is prepared by peeling off the substrate 100 from the active matrix substrate prepared in Example 1 and pasting it with a plastic substrate will be described below.
(116) In
(117) First, according to Example 1, after the active matrix substrate of the state in
(118) Subsequently, an opposing substrate which is to be a supporting body 407 is prepared for. A color filter (not shown) in which a colored layer and a radiation shield layer were arranged corresponding to the respective pixels has been provided on this opposing substrate. Moreover, a radiation shield was provided on the portion of the drive circuit. A flattening film (not shown) for covering this color filter and the radiation shield layer was provided. Subsequently, an opposing electrode 408 consisted of a transparent electrically conductive film was formed on the flattening film in the pixel section, an orientation film 406b was formed on the whole surface of the opposing substrate, and the rubbing processing was provided.
(119) Then, an active matrix substrate 400 in which the pixel section and the drive circuit were formed and the supporting body 407 are pasted together with a sealing medium which is to be an adhesive layer 409. Into a sealing medium, filler is mixed, two sheets of substrates are pasted together with uniform interval by this filler and a spacer in a column shape. Then, between both substrates, a liquid crystal material 410 is implanted and completely sealed with a sealing compound (not shown) (
(120) Subsequently, the substrate 400 on which the nitride layer or metal layer 401 has been provided is pulled away by the physical means (
(121) In this way, a flexible active matrix type liquid crystal display device is completed. Then, if necessary, the flexible substrate 412 or an opposing substrate is cut down in the desired shape. Furthermore, a polarizing plate (not shown) or the like was appropriately provided using the known technology. Then, a FPC (not shown) was pasted using the known technology.
Example 3
(122) In the Example 2, an example in which after an opposing substrate as a supporting body was pasted and a liquid crystal was implanted, the substrate was peeled off and a plastic substrate was pasted as a transferring body was shown. However, in the present Example, an example in which after an active matrix substrate shown in
(123) In
(124) First, according to Example 1, after an active matrix substrate in the state of
(125) Subsequently, it is pasted with an adhesive layer 506 consisted of an epoxy resin or the like on a transferring body 507 (first transferring body). In the present Example, it can be made light by using plastic film substrate for the transferring body 507 (
(126) Then, a plastic film substrate 507 in which the pixel section and the drive circuit were adhered and the supporting body 510 are pasted together with a sealing medium which is to be an adhesive layer 512 (
(127) In this way, a flexible active matrix type liquid crystal display device is completed. Then, if necessary, the flexible substrate 507 or an opposing substrate is cut in the desired shape. Furthermore, a polarizing plate (not shown) or the like was appropriately provided using the known technology. Then, a FPC (not shown) was pasted using the known technology.
Example 4
(128) The structure of the liquid crystal module obtained by Example 2 or Example 3 is described with reference to the top view in
(129) A pixel portion 304 is placed in the center of a substrate 301. A source signal line driving circuit 302 for driving source signal lines is positioned above the pixel portion 304. Gate signal line driving circuits 303 for driving gate signal lines are placed to the left and right of the pixel portion 304. Although the gate signal line driving circuits 303 are symmetrical with respect to the pixel portion in this Example, the liquid crystal module may have only one gate signal line driving circuit on one side of the pixel portion. Of the above two options, a designer can choose the arrangement that suits better considering the substrate size or the like of the liquid crystal module. However, the symmetrical arrangement of the gate signal line driving circuits shown in
(130) Signals are inputted to the driving circuits from flexible printed circuits (FPC) 305. The FPCs 305 are press-fit through an anisotropic conductive film or the like after opening contact holes in the interlayer insulating film and resin film and forming a connection electrode 309 so as to reach the wiring lines arranged in given places of the substrate 301. The connection electrode is formed from ITO in this Example.
(131) A sealing agent 307 is applied to the substrate along its perimeter surrounding the driving circuits and the pixel portion. An opposite substrate 306 is bonded to the substrate 301 by the sealing agent 307 while a spacer formed in advance on the film substrate keeps the distance between the two substrates constant. A liquid crystal element is injected through an area of the substrate that is not coated with the sealing agent 307. The substrates are then sealed by an encapsulant 308. The liquid crystal module is completed through the above steps.
(132) Although all of the driving circuits are formed on the film substrate in the example shown here, several ICs may be used for some of the driving circuits.
(133) This Example may be combined with Example 1.
Example 5
(134) Example 1 shows an example of reflective display device in which a pixel electrode is formed from a reflective metal material. Shown in this Example is an example of transmissive display device in which a pixel electrode is formed from a light-transmitting conductive film.
(135) The manufacture process up through the step of forming an interlayer insulating film is identical with the process of Example 1, and the description thereof is omitted here. After the interlayer insulating film is formed in accordance with Example 1, a pixel electrode 601 is formed from a light-transmitting conductive film. Examples of the light-transmitting conductive film include an ITO (indium tin oxide alloy) film, an indium oxide-zinc oxide alloy (In.sub.2O.sub.3ZnO) film, a zinc oxide (ZnO) film, and the like.
(136) Thereafter, contact holes are formed in an interlayer insulating film 600. A connection electrode 602 overlapping the pixel electrode is formed next. The connection electrode 602 is connected to a drain region through the contact hole. At the same time the connection electrode is formed, source electrodes or drain electrodes of other TFTs are formed.
(137) Although all of the driving circuits are formed on the substrate in the example shown here, several ICs may be used for some of the driving circuits.
(138) An active matrix substrate is completed as above. After peeling the substrate by using this active matrix substrate to bond plastic substrates, a liquid crystal module is manufactured in accordance with Examples 2 to 4. The liquid crystal module is provided with a backlight 604 and a light guiding plate 605, and is covered with a cover 606 to complete the active matrix liquid crystal display device of which a partial sectional view is shown in
(139) This Example may be combined with Examples 1 to 4.
Example 6
(140) In the present Example, an example in which a light emitting device having an organic light emitting device (OLED) formed on a plastic substrate is prepared is shown in
(141) In
(142) It should be noted that the reference numerals 601-603 provided on the substrate 600 may be formed according to Embodiment 2 through 4.
(143) These elements (including 604a, 604b and 604c) may be prepared according to the n-channel type TFT 201 of the above-described Example 1 and/or the p-channel type TFT 202 of the above-described Example 1.
(144) An OLED 605 has a layer containing an organic compound (organic light emitting material) obtaining electroluminescence generating by adding electric field (hereinafter, referred to as organic light emitting layer), an anode layer and a cathode layer. Although as for electroluminescence in organic compounds, there are a luminescence (fluorescence) generated when returning from singlet excitation state to ground state and a luminescence (phosphorescence) generated when returning from triplet state to ground state, a light emitting device of the present invention may use either of the above-described luminescences or both the above-described luminescences. It should be noted that in the present specification, all of the layers formed between the anode and cathode of OLED are defined as an organic light emitting layer. Concretely, organic light emitting layers include a light emitting layer, a hole injection layer, an electronic injection layer, a hole transport layer, an electron transport layer or the like. Fundamentally, OLED has a structure in which anode/light emitting layer/cathode are in turn laminated, in addition to this structure, there may be also some structures having anode/hole injection layer/light emitting layer/cathode or anode/hole injection layer/light emitting layer/electron transport layer/cathode or the like are in turn laminated. According to the above-described method, the state of
(145) Subsequently, the substrate 600 on which the nitride layer or metal layer 601 has been provided is pulled away by the physical means (
(146) In this way, a flexible light emitting device sandwiched between the supporting body 608 having the flexibility and the transferring body 610 having the flexibility can be obtained. It should be noted that if the supporting body 608 and the transferring body 610 are made of the same material, the coefficients of thermal expansion become equal, therefore, the influence from the stress distortion due to the change of temperature can be made not easily exerted.
(147) Then, if necessary, the supporting body 608 having the flexibility and the transferring body 610 are cut in the desired shape. Then, a FPC (not shown) was pasted using the known technology.
Example 7
(148) In Example 6, an example in which after the supporting body was pasted, the substrate was peeled off and a plastic substrate as a transferring body was pasted has been shown. However, in the present Example, an example in which after the substrate was peeled off, a plastic substrate as the first transferring body and a plastic substrate as the second transferring body are pasted and a light emitting device equipped with an OLED is prepared will be shown.
(149) In
(150) It should be noted that the reference numerals 701-703 provided on the substrate 700 might be formed according to any of Embodiment 2 through 4.
(151) These elements (including 704a, 704b and 704c) may be prepared according to the n-channel type TFT 201 of the above-described Example 1, the p-channel type TFT 202 of the above-described Example 1.
(152) According to the above-described method, the state of
(153) Subsequently, the base member (second transferring body) 708 is pasted together by the adhesive layer 707 (
(154) Then, if necessary, the base member 708 having the flexibility and the transferring body 710 are cut in the desired shape. Then, a FPC (not shown) was pasted using the known technology.
Example 8
(155) In Example 6 or Example 7, an example in which a flexible light emitting device sandwiched between substrates having the flexibility is obtained has been shown. However, since a substrate consisted of a plastic in general easily transmits water content and oxygen, and the deterioration of an organic light emitting layer is promoted by these, the life-span of the light emitting device easily tends to be shorter.
(156) Hence, in the present Example, on a plastic substrate, a plurality of films for preventing oxygen and water content from penetrating into the organic light emitting layer of OLED (hereinafter, referred to as barrier film) and a layer (stress relaxation film) having a smaller stress than the foregoing barrier film between the foregoing barrier films each other are provided. In the present specification, a film in which a barrier film and a stress relaxation film are laminated is referred to as sealing film.
(157) Concretely, two or more layers of barrier films consisted of inorganic matters (hereinafter, referred to as barrier film) are provided, and further, a stress relaxation film having a resin between the relevant two-layer barrier films (hereinafter, referred to as stress relaxation film) is provided. Then, a light emitting device is formed by forming an OLED on the relevant three or more-layer insulating film and tightly sealing. It should be noted that since Example 6 and Example 7 are the same except for the substrate, here, the description on them is omitted.
(158) As shown in
(159) Here, a layer consisted of a silicon nitride is film-formed as a barrier film 811a on the film substrate 810 by a sputtering method, a stress relaxation film 811b having polyimide is film-formed on the barrier film 811a, a layer consisted of a silicon nitride is film-formed as the barrier film 811c on the stress relaxation film 811b by a sputtering method. A layer in which the barrier film 811a, the stress relaxation film 811b, and the barrier film 811c are laminated is generally referred to as the sealing film 811. Then the film substrate 810 on which the relevant sealing film 811 is formed may be pasted together using the second adhesive layer 809 on the peeled layer containing an element.
(160) Similarly, a layer consisted of a silicon nitride is formed as a barrier film 814a on the film substrate 812 by a sputtering method, and a stress relaxation film 814b having polyimide is formed on the barrier film 814a. A layer consisted of a silicon nitride is formed as the barrier film 814c on the stress relaxation film 814b by a sputtering method. A layer in which the barrier film 814a, the stress relaxation film 814b, and the barrier film 814c are laminated is generally referred to as the sealing film 814. Then the film substrate 812 on which the relevant sealing film 814 is formed may be pasted together using the second adhesive layer 809 on the peeled layer containing an element.
(161) It should be noted that as for a barrier film, if two layers or more are provided, it might be available. Then, as a barrier film, a silicon nitride, a silicon oxynitride an aluminum oxide, an aluminum nitride, an aluminum oxynitride or an aluminum silicide oxynitride (AlSiON) can be used.
(162) Since an aluminum silicide oxynitride is comparatively high in thermal conductivity, the heat generated in an element can be efficiently discharged by utilizing it as a barrier film.
(163) Moreover, for a stress relaxation film, a resin having a transparency can be used. Representatively, polyimide, acryl, polyamide, polyimideamide, benzocyclobutene, epoxy resin or the like is capable of being used. It should be noted that resins except for resins described above could be also used. Here, after polyimide which is a type thermally polymerized was coated, it is burned and formed.
(164) The film formation of a silicon nitride is performed at 0.4 Pa of sputtering pressure by introducing argon, maintaining the substrate temperature as 150 C. Then, using a silicon as a target, the film formation was performed by introducing nitrogen and hydrogen except for argon. In the case of a silicon oxynitride, the film formation is performed at about 0.4 Pa of sputtering pressure by introducing argon and maintaining the substrate temperature as 150 C. Then, using a silicon as a target, the film formation was performed by introducing nitrogen, nitrogen dioxide and hydrogen except for argon. It should be noted that as a target, a silicon oxide might be used.
(165) It is desirable that the film thickness of the barrier film is in the range from 50 nm to 3 m. Here, a silicon nitride was formed in film thickness of
(166) It should be noted that the film formation method of a barrier film is not limited only to sputtering method, the person who carries out it can appropriately set its method. For example, the film formation may be performed using a LPCVD method, a plasma CVD method or the like. Moreover, it is desirable that the film thickness of the stress relaxation film is in the range from 200 nm to 2 m. Here, polyimide was formed in film thickness of 1 m.
(167) An OLED can be completely interrupted from the air by applying a plastic substrate on which a sealing film of the present Example is provided as the supporting body 608 or the transferring body 610 in Example 6 or the base member 708 or the transferring body 710 in Example 7, thereby capable of nearly completely suppressing the deterioration of an organic light emitting material due to oxidation, and capable of largely enhancing the reliability of an OLED.
Example 9
(168) The constitution of a module having an OLED obtained according to Example 6 or Example 7, what is called the constitution of an EL module will be described below with reference to a top view of
(169) Moreover, here not shown in Figs., in order to prevent the background from being reflected due to the reflection of the applied metal layer (here, cathode or the like), a circular polarizing means referred to as a circular polarizing plate consisted of a phase difference plate (/4 plate) and polarizing plate may be provided on the substrate 900.
(170) It should be noted that the reference numeral 908 denotes a wiring for transmitting a signal inputted into the source side drive circuit 901 and the gate side drive circuit 903, it receives a video signal and a clock signal from FPC (Flexible Print Circuit) which is an external input terminal. Moreover, a light emitting device of the present Example may be of a digital drive, or an analog drive, or a video signal may be a digital signal, or an analog signal. It should be noted that here, only FPC is shown in Figs., but a print wiring base (PWB) may be mounted on this FPC. It is defined that a light emitting device in the present specification includes not only the main body of the light emitting device but also the state where FPC or PWB is mounted on the main body. Moreover, although a complex integrated circuit (memory, CPU, controller, D/A converter or the like) are capable of being formed on the same substrate with these pixel section and drive circuit, the fabrication with a small number of masks is difficult. Therefore, it is preferred that an IC chip equipped with a memory, a CPU, a controller, a D/A converter or the like is mounted by COG (Chip On Glass) method, or TAB (Tape Automated Bonding) method or a wire bonding method.
(171) Next, the sectional structure will be described below with reference to
(172) These TFTs (including 911, 913 and 914) may be fabricated according to the n-channel type TFT 201 of the above-described Example 1, the p-channel type TFT 202 of the above-described Example 1.
(173) It should be noted that as an insulating film provided between the TFT and OLED, it is preferable that a material for not only blocking the diffusion of the impurity ion such as alkali metal ion, alkaline earth metal ion or the like, but also aggressively absorbing the impurity ion such as alkali metal ion, alkaline earth metal ion or the like, and further, a material endurable for the temperature of later processes is suitable. As a material suitable for these conditions, as one example, a silicon nitride film containing a large amount of fluorine is listed. The fluorine density containing in the film of the silicon nitride film is 110.sup.19/cm.sup.3 or more, preferably, the composition ratio of fluorine is made in the range from 1 to 5%. The fluorine in the silicon nitride film is bonded to alkali metal ion, alkaline earth ion or the like, and absorbed in the film. Moreover, as the other example, an organic resin film containing a fine particle consisted of antimony (Sb) compound, tin (Sn) compound or indium (In) compound, for example, an organic resin film containing antimony pentaoxide fine particle (Sb.sub.2O.sub.5.nH.sub.2O) is also listed. It should be noted that this organic resin film contains a fine particle having 10-20 nm in average particle diameter, and light transmittance is also very high. An antimony compound represented by this antimony pentaoxide fine particle easily absorbs impurity ion such as alkali metal ion or alkaline earth metal ion.
(174) Moreover, as the other material of an insulating film provided between the active layer of TFT and the OLED, a layer indicated by AlN.sub.xO.sub.y may be used. An oxynitride layer (layer indicated by AlN.sub.xO.sub.y) obtained by performing the film formation under the atmosphere that argon gas, nitride gas, nitrogen gas and oxygen gas are mixed using aluminum nitride (AlN) target by a sputtering method is a film containing nitrogen in the range from 2.5 atm % to 47.5 atm %, characterized by the fact that it has an effect capable of blocking water content and oxygen, in addition to this, has a high thermal conductivity and an effect of heat release, and further, has a very high translucency. In addition, it can prevent impurities such as alkali metal, alkaline earth metal or the like from penetrating into the active layer of TFT.
(175) The pixel electrode 912 functions as an anode of the OLED. Moreover, a bank 915 is formed on both ends of the pixel electrode 912, an EL layer 916 and a cathode 917 of the light emitting element are formed on the pixel electrode 912.
(176) As the EL layer 916, an EL layer (layer for light emitting and making carrier perform the migrate for it) may be formed by freely combining the light emitting layer, a charge injection layer or a charge implantation layer. For example, low molecular system organic EL material and high molecular system organic EL material may be employed. Moreover, as an EL layer, a thin film consisted of a light emitting material (singlet compound) which light-emits (fluorescence) due to singlet excitation, or a thin film consisted of a light emitting material (triplet compound) which emits (phosphorescence) due to triplet excitation can be used. Moreover, an inorganic material such as silicon carbide or the like is capable of being used as a charge transport layer and a charge injection layer. For these organic EL material and inorganic material, the known materials can be used. The cathode 917 also functions the wiring common to the all of the pixels, and electrically connected to the FPC 909 via the connecting wiring 908. And further, elements contained in the pixel section 902 and on the gate side drive circuit 903 are all covered by the cathode 917, the sealing member 918, and the protective film 919.
(177) It should be noted that as, the sealing member 918, it is preferable that a material being transparent to the visible light or semitransparent is used if it is possible. Moreover, it is desirable that the sealing member 918 is a material for transmitting water content and oxygen as little as possible.
(178) Moreover, after the light emitting element was completely covered by utilizing the sealing member 918, it is preferred that the protective film 919 consisted of at least DLC film or the like is provided on the surface (exposed surface) of the sealing member 918 as shown in
(179) The light emitting element can be completely interrupted from the external by sealing the light emitting element with the sealing member 918 and the protective film in the above-described structure, and it can prevent the substances promoting the deterioration due to the oxidation of EL layer occurred by water content, oxygen or the like from the external from penetrating. In addition to this, if a film having a thermal conductivity (AlON film, AlN film or the like) is used as a protective film, the heat generated when it is driven can be released. Therefore, alight emitting device with high reliability can be obtained.
(180) Moreover, the pixel electrode is made a cathode, the EL layer and the anode are laminated and it may be configured so that the light is emitted in the reverse direction. Its one example is shown in
(181) The sectional structure shown in
(182) The pixel electrode 1012 functions as a cathode of the light emitting element. Moreover, a bank 1015 is formed on both ends of the pixel electrode 1012, an EL layer 1016 and an anode 1017 of the light emitting element are formed on the pixel electrode 1012.
(183) The anode 1017 also functions as the common wiring to all of the pixels, and electrically connected to the FPC 1009 via a connecting wiring 1008. Furthermore, the element contained in the pixel section 1002 and the gate side drive circuit 1003 are all covered by the protective film 1019 consisted of the anode 1017, the sealing member 1018 and DLC or the like. Moreover, the covering member 1021 and the substrate 1000 were pasted using the adhesive. Moreover, the concave portion is provided on the covering member, and the desiccant 1021 is set on the covering member.
(184) It should be noted that as the sealing member 1018, it is preferable that a material being transparent to the visible light or semitransparent is used if it is possible. Moreover, it is desirable that the sealing member 1018 is a material for transmitting water content and oxygen as little as possible.
(185) Moreover, in
(186) Moreover, here not shown in Figs., in order to prevent the background from being reflected due to the reflection of the applied metal layer (here, cathode or the like), a circular polarizing means referred to as a circular polarizing plate consisted of a phase difference plate (/4 plate) and polarizing plate may be provided on the covering member 1020.
(187) Since in the present Example 1, a TFT having a highly qualified electric characteristics and a high reliability obtained in Example 1 is used, a light emitting element having a higher reliability comparing to those of the conventional elements can be formed. Moreover, an electric apparatus having a high performance can be obtained by utilizing a light emitting device having such light emitting elements as a display section.
(188) It should be noted that the present Example could be freely combined with Example 1, Example 7, Example 8 or Example 9.
(189) The present invention can enhance the reliability of an element without damaging the semiconductor layer since peeling off from the substrate by the physical means.
(190) Moreover, the present invention is capable of peeling off not only a peeled off layer having a small area but also a peeled off layer having a large area over the entire surface at excellent yield ratio.
(191) In addition, since the present invention is capable of easily peeling off by the physical means, for example, is capable of pulling away by human's hands, it can be said that the process is suitable for mass production. Moreover, in the case where a manufacturing equipment is prepared in order to pull away the peeled off layer when performing the mass production, a large size fabrication equipment can also be prepared at low cost.
Example 10
(192) Various modules (active matrix liquid crystal module, active matrix EL module and active matrix EC module) can be completed by the present invention. Namely, all of the electronic apparatuses are completed by implementing the present invention.
(193) Following can be given as such electronic apparatuses: video cameras; digital cameras; head mounted displays (goggle type displays); car navigation systems; projectors; car stereo; personal computers; portable information terminals (mobile computers, mobile phones or electronic books etc.) etc. Examples of these are shown in
(194)
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(203) In addition, the display shown in
(204) As described above, the applicable range of the present invention is very large, and the invention can be applied to electronic apparatuses of various areas. Note that the electronic devices of this Example can be achieved by utilizing any combination of constitutions in Examples 1 to 9.