MANUFACTURING OF SUBSTRATES COATED WITH A CONDUCTIVE LAYER

Abstract

The invention relates to a technique of manufacturing a coated substrate (102) such as glass (104) carrying a conductive layer (112) such as a metal layer to be tempered after deposition. A system (100) for manufacturing the coated substrate (102) may comprise a sputtering configuration (120) adapted for depositing the conductive layer (112) on the substrate (104). A pulse laser (132) is adapted for irradiating the conductive layer (112) with laser pulses (136). The pulse laser (132) is adapted for laser pulses (136) with a pulse duration below one microsecond.

Claims

1: A method of manufacturing a coated substrate, the method comprising: depositing on the substrate a coating system comprising in order from the glass substrate outwardly at least a first dielectric layer, a conductive infrared radiation reflecting layer and a second dielectric layer, and irradiating the conductive layer with laser pulses, wherein a pulse duration of the laser pulses is below one microsecond.

2: The method according to claim 1, wherein the pulse duration is less than 100 nanoseconds.

3: The method according to claim 1, wherein a wavelength of a radiation of the laser pulses is between 500 nanometers and 2500 nanometers.

4: The method according to claim 1, wherein a fluence of the laser pulses is between 0.2 millijoule per square millimeter and 100 millijoule per square millimeter.

5: The method according to claim 1, wherein a pulse energy per pulse of the laser pulses is between 1 millijoule and 1000 millijoule.

6: The method according to claim 1, wherein a pulse frequency of the laser pulses is between 1 kilohertz and 100 kilohertz.

7: The method according to claim 1, wherein the conductive layer comprises a metal.

8: The method according to claim 1, wherein the conductive layer is a silver-comprising layer.

9: The method according to claim 1, wherein the coating system deposited on the substrate comprises in order from the glass substrate outwardly at least a first dielectric layer, a first conductive layer, a second dielectric layer, a second conductive layer and a third dielectric layer.

10: The method according to claim 1, wherein the coating system deposited on the substrate comprises at least one of the following: a barrier layer, a blocker layer, an absorber layer, a seed layer.

11: The method according to claim 1, wherein said irradiating the conductive layer is performed after said depositing completion of the coating system deposition step.

12: A system for manufacturing a coated substrate, comprising: a component adapted for depositing on the substrate a coating system comprising in order from the glass substrate outwardly at least a first dielectric layer, a conductive infrared radiation reflecting layer and a second dielectric layer, and a pulse laser adapted for irradiating the conductive layer with laser pulses, wherein the pulse laser is adapted for laser pulses with a pulse duration below one microsecond.

13: The system according to claim 12, wherein the pulse laser comprises at least one of an Yb:YAG laser, Nd:YAG laser or Nd:glass laser.

14. (canceled)

15: The method according to claim 1, wherein the pulse duration is less than 50 nanoseconds.

16: The method according to claim 1, wherein a wavelength of a radiation of the laser pulses is between 1000 nanometers and 1100 nanometers.

17: The method according to claim 1, wherein a fluence of the laser pulses is between 1 millijoule per square millimeter and 20 millijoule per square millimeter.

18: The method according to claim 1, wherein a pulse energy per pulse of the laser pulses is between 10 millijoule and 300 millijoule.

19: The method according to claim 1, wherein a pulse energy per pulse of the laser pulses is between 30 millijoule and 150 millijoule.

20: The method according to claim 1, wherein a pulse energy per pulse of the laser pulses is between 50 millijoule and 80 millijoule.

21: The method according to claim 1, wherein a pulse frequency of the laser pulses is between 3 kilohertz and 30 kilohertz.

Description

[0047] In the following, the invention will further be described with reference to exemplary embodiments illustrated in the drawing by way of example only. In the drawing

[0048] FIG. 1 schematically illustrates an embodiment of a system for manufacturing a coated substrate according to the invention;

[0049] FIG. 2 is a flow diagram illustrating an operation of the system of FIG. 1;

[0050] FIG. 3 schematically illustrates spots of laser pulses on a coated substrate according to an embodiment of the invention;

[0051] FIG. 4 illustrates a time sequence of laser pulses irradiated onto a coated substrate according to an embodiment of the invention;

[0052] FIG. 5A schematically illustrates a first specific embodiment of a coating system manufactured according to the invention;

[0053] FIG. 5B schematically illustrates a second specific embodiment of a coating system manufactured according to the invention;

[0054] FIG. 5C schematically illustrates a third specific embodiment of a coating system manufactured according to the invention; and

[0055] FIG. 5D schematically illustrates a fourth specific embodiment of a coating system manufactured according to the invention.

[0056] FIG. 1 schematically illustrates a system or plant 100 for manufacturing a product 102 comprising a substrate 104 with a coating system 106 being deposited during a manufacturing process. The product 102 may be a pre-product intended for further manufacturing after output from system 100, however is referenced only as a ‘product’ herein for short. System 100 may comprise more than the sections and functions illustrated in FIG. 1 and discussed hereinbelow, however such other sections and functions are currently considered not indispensable for implementing the invention and are therefore omitted.

[0057] It is assumed that substrate 104 is transported from left to right as indicated by arrow 108 such that FIG. 1 may also be interpreted as illustrating a sequence in time of manufacturing product 102. An operation 200 of system 100 for manufacturing the product 102 will be described with additional reference to the flow diagram of FIG. 2.

[0058] The manufacturing process 200 comprises a step 202 of performing a coating process for depositing the coating system 106 on the substrate 102. The coating process 202 is illustrated schematically by section 110 of system 100 in FIG. 1.

[0059] Specifically, substrate 104 may comprise a glass substrate. The coating process 202 may comprise depositing a conductive layer, specifically a silver-comprising layer 112 on the glass substrate 104. The coating process 202 may further comprise depositing other layers below 114 and above 116 silver layer 112 on the substrate 104. Layers 114, 116 may comprise multiple sublayers and may comprise one or more of a dielectric layer, barrier layer, another silver layer, etc.

[0060] Section 110 of system 100 may comprise a process chamber 118 for example for providing vacuum (evacuated, low pressure) conditions for depositing one or more of the layers 112, 114, 116. Specifically, as indicated in FIG. 1, a sputtering configuration 120 may be provided which includes a sputtering target 122 for providing a target material 124. For a sputtering process for depositing the silver-comprising layer 112, the target material 124 may comprise silver and optionally other materials such as one or more dopants for optimizing the sputtering process, optical or other properties of the product 102, etc.

[0061] In step 204, the substrate 104 coated with the coating system 106 is subjected to a tempering process for optimizing properties of the sputtered silver-comprising layer 112. The tempering process 202 is illustrated schematically by section 126 of system 100 in FIG. 1.

[0062] According to the specific example illustrated in FIG. 1, the coated substrate 104/106 is transported along the direction indicated by arrow 108 from section 110 to section 126. Section 126 may comprise a process chamber 128 which may not necessarily provide vacuum conditions, but which conforms to safety prescriptions for laser systems.

[0063] Substrate 104 and coating system 106 are illustrated as continuously transported along sections 110 and 126, however in practical implementations the chambers 118 and 128 may each be configured for processing product 102 as a piece of coated substrate of predefined dimensions; for example, the pieces may be rectangular with side lengths of several meters. Therefore, chambers 118 and 128 may in general be implemented as separate chambers which may be spaced apart from each other, optionally with other compartments or chambers between. According to some embodiments, chamber 128 may be located near the end of a manufacturing line implementing the system 100 and may for example comprise the last compartment prior to a gate for outputting the coated substrate 104/106, i.e. product 102.

[0064] The tempering process of step 204 in section 126 may comprise irradiating the coated substrate 104/106 with laser radiation. In this respect, laser configuration 130 is provided which may comprise, amongst others, a laser 132 and irradiation arrangement 134. Specifically, laser 132 may comprises one or more pulse lasers (also termed ‘pulsed lasers’ in the field) specifically adapted for providing short pulses of pulse duration below 1 microsecond, i.e. in the range of nanoseconds. A presently preferred range is between 1 nanosecond and 50 nanoseconds, which does not exclude applications with pulses even in the range of picoseconds. Additionally or alternatively to truly pulsed lasers, short pulses may be generated from longer pulses or continuous laser radiation by the irradiation arrangement, e.g. by appropriately opening and closing an aperture.

[0065] Laser radiation 136 comprising short laser pulses is provided via irradiation arrangement 134 to coated substrate 104/106 in an incidence area 138. Irradiation arrangement 134 may comprise focusing, beam-forming and/or positioning arrangements for correspondingly modifying laser radiation 136.

[0066] The laser 132 may comprise a solid-state laser and/or a Q-switched laser. It may take the form, for example, of a disk laser or a fiber laser. As specific examples, the pulse laser 132 may comprise an neodymium-doped glass or ceramics laser (e.g., Nd:YAG), a neodymium-doped glass laser (Nd:glass) and/or an ytterbium-doped glass or ceramics laser (e.g., Yb:YAG), wherein choice of laser type may depend on the available pulse energies. Wavelengths of emitted laser radiation 136 of 1030 nanometers (nm) (Yb:YAG), 1064 nm (Nd:YAG) and/or 1070 nm (Nd:glass) have been found appropriate. Other types of laser could be used, for example, Er:YAG or Ho:YAG laser, optionally with second, third or higher order harmonic generation. Other wavelengths may be preferred depending on absorption properties in the conductive layer 112 and/or transparency properties of the other layers 114, 116. For other embodiments, optionally also a transparency of the substrate for laser radiation has to be considered if an irradiation of the conductive layer is performed via the substrate.

[0067] In step 206, the manufacturing process 200 ends, for example by providing the coated and tempered product 102 to further or other manufacturing equipment, e.g. for portioning, etc.

[0068] FIG. 3 schematically illustrates a view from above as indicated by arrow 140 in FIG. 1 onto the coated substrate 104/106. Shown by dashed lines are spots 302 wherein each spot 302 marks the impact of a pulse of laser radiation 136 onto the coated substrate 104/106 in incidence area 138. Spot 302 size may be formed by irradiation arrangement 134 on the coated substrate 104/106. It is noted that dimensions of the coated substrate 104/106 and of the spots 302/incidence area 138 may not be drawn to scale. Various non-overlapping or contacting spots 302 are shown in FIG. 3 for clarity. However, in a practical implementation various spots may contact or overlap each other to form an overall irradiated surface.

[0069] If a single laser 132 is employed, irradiation arrangement 134 may arrange for a lateral displacement of incidence area 138 along directions indicated by double arrow 304 to form a sequence of spots 302 side-by-side. Due to a relative dislocation between laser source 130 and coated substrate 104/106, e.g. due to a transport of the coated substrate 104/106 into the direction indicated by arrow 108 and/or a movement of a focusing section of irradiation arrangement 134, subsequent spots may be shifted along the transversal direction 108 as indicated in FIG. 3. According to other embodiments, a laser device may not only be arranged for lateral displacement as indicated with arrow 304 in FIG. 3, but may alternatively additionally be arranged for transversal displacement.

[0070] Details of how to achieve complete coverage of the surface 306 of coated substrate 104/106 to be irradiated for tempering the silver-comprising layer 112 are known to the skilled person. For example, the pulse impact areas or spots 302 are exemplarily shown as being of rectangular or nearly quadratic shape. While various shapes can be contemplated, a rectangular or quadratic spot shape can exemplarily be employed to achieve an efficient coverage of the area 306. As specific examples, the pulse spots 302 may cover an area 308 of about 10 square millimeters, wherein sides 310 of spots 302 may have lengths of about 3 millimeters. Sizes may vary during manufacturing for example according to varying incidence angles of the radiation 136.

[0071] Each spot 302 may preferably result from one and exactly one laser pulse to ensure desired energy input on adiabatic or near-adiabatic short timescale. Per spot 302, an energy, i.e. a pulse energy per laser pulse, between 10 millijoule and 300 millijoule may be deposited. As a specific example, the pulsed radiation 136 may have a fluence of between about 5 millijoule per square millimeter and 8 millijoule per square millimeter for each of the spots 302.

[0072] FIG. 4 illustrates a time sequence 400 of laser pulses 402 of radiation 136 irradiated onto the coated substrate 104/106. A pulse duration 404 and time span 406 may not be drawn to scale.

[0073] Specifically, the sequence 400 of pulses 402 may result in the sequence of spots 302 illustrated in FIG. 3. A pulse duration 404 of the pulses may exemplarily be assumed to be 30 nanoseconds. The time 406 between successive pulses may exemplarily be assumed to be around 100 microseconds. As a result, a pulse frequency is about 10 kilohertz and a duty cycle of laser configuration 130 is about 0.0003. The duty cycle is understood herein as the ratio of a pulse duration to a time between two successive pulses. Generally, a duty cycle may be below 10%, preferably below 1%.

[0074] Pulses 402 are illustrated in FIG. 4 as having a common pulse duration 404, which may not generally or necessarily be the case. For example, pulse durations and/or spot sizes may vary according to an incidence angle of the irradiation 136. Generally, for a given type of laser a pulse duration is mostly fixed, i.e. can be varied only slightly around a fixed value, while pulse energy and/or intensity can be varied, in principle even from pulse to pulse. In practice, therefore, a desired specific energy input (i.e., per unit area) may be achieved for a given type of laser by varying a pulse energy, or may be achieved by considering a desired pulse duration (and energy) and selecting an appropriate type of laser.

[0075] The embodiments illustrated in FIGS. 1-4 may demonstrate the surprising insight that when a particularly short pulsed laser is used for depositing an energy required for tempering a silver-comprising layer (more generally, metal-comprising layer or conductive layer) of a coated substrate, it is possible to minimize negative effects of the tempering on the other coating layers. However, such insight is not dependent on the purely exemplary numerical values given above to further illustrate the invention. In fact, when representing technical configurations by sets of numerical values indicating, for example, pulse energy, pulse duration, spot size, etc., a plurality of different number sets can be contemplated, calculated and/or determined by experiments which can achieve one or more of the advantages of the invention. The choices of process parameter values depend on the specifics of the coating system including the conductive layer, the substrate and the desired tempering effect, the available laser system, etc.

[0076] As only one example, the energy to be absorbed by the conductive layer is determined by the desired tempering effects. Based on an amount of energy available per laser pulse, a spot size may then be calculated. As a further example, the pulse frequency of the laser pulses may be selected according to the properties of the employed laser, the employed irradiation arrangement, a desired relative transport velocity of laser configuration 130 vs. substrate 104, etc. Spot sizes and/or fluence may be set according to available energy per pulse and desired energy input per area of the coated substrate/conductive layer.

[0077] It is noted that according to preferred embodiments it is intended that any point of the coated substrate surface to be irradiated should be covered by one laser pulse spot only, which presumably is advantageous to achieve the adiabatic or near-adiabatic effects discussed further above. The energy to be irradiated and absorbed by the silver-comprising layer should preferably be irradiated to the incidence area/spot in a time short enough to achieve the adiabatic effect, i.e. the desired energy input should be irradiated in a short pulse in contrast to a conventional continuous emission or longer pulse of presumably lower irradiation intensity. On the other hand, the pulses do not need to be shorter as required for avoiding undesirable deteriorations of other coating layers.

[0078] FIGS. 5A to 5D illustrate examples of coated substrates including coating systems which can be manufactured by a system such as, for example, system 100 of FIG. 1 and according to a process such as, for example, process 200 of FIG. 2. A silver-comprising layer is again considered as example for a conductive layer in a coated (glass) substrate. For each of the exemplary embodiments the tempering of the one or more silver-comprising layers may be performed after the respective coating system has been deposited on the substrate. It is to be noted that relative layer thicknesses as illustrated in FIGS. 5A-5D are not drawn to scale.

[0079] FIG. 5A illustrates a coated substrate 500 comprising a substrate 502 and coating system, stack, or layer composition 504. As illustrated, substrate 502 may comprise glass. The layer composition 504 includes multiple coating layers comprising a single silver layer 506 embedded within various other layers including dielectric layers. Substrate 502 and coating system 504 may be intended for a low-E product.

[0080] As illustrated in FIG. 5A, the coated substrate 500 comprises the following layers: Glass/barrier layer/BiO.sub.x and/or Si.sub.3N.sub.4/Ag/NiCr/BiO.sub.x. The barrier layer may, for example, comprise SiO.sub.x. Instead of NiCr, other absorber materials such as Ni alloys may be employed.

[0081] Surprisingly it has been found that when employing a short pulsed laser with pulses shorter than 1 microsecond for tempering the silver layer 506, one or more of the effects of the invention as discussed above can be achieved. In particular, a desired annealing of the silver layer 506 can be performed while minimizing negative effects on the other layers of coating system 504.

[0082] FIG. 5B illustrates a coated substrate 520 comprising a glass substrate 522 and coating system 524. The coating system 524 comprises multiple coating layers comprising a single silver layer 526 embedded within various other layers. The coated substrate 520 represents another example of a low-E product.

[0083] As illustrated in FIG. 5B, the coated substrate 520 comprises the following layers: Glass/optionally SiO.sub.x and/or Si.sub.3N.sub.4/TiO.sub.x/ZnO.sub.x/Ag/ZnO.sub.x/TiO.sub.x/ZnSnO.sub.x/optionally Si.sub.3N.sub.4 and/or SiO.sub.x. Instead of ZnSnO.sub.x, TiN could be used. The TiO.sub.x layers can have, for example, a thickness of about 20 nm-50 nm. The silver layer 526 may have a thickness of 1 nm-20 nm, preferred 4 nm-18 nm, more preferred 6 nm-17 nm. The precise value may be dependent on the intended ‘low-E’ emissivity properties, for a value of ∈=1.1 a preferred silver layer thickness may be between 10 nm-13 nm. A thickness of the optional barrier layers comprising SiO.sub.x and/or Si.sub.3N.sub.4 can be selected below 10 nm.

[0084] Surprisingly it has been found that when employing a short pulsed laser with pulses shorter than 1 microsecond for tempering the silver layer 526, one or more of the effects of the invention as discussed above can be achieved. In particular, a desired annealing of the silver layer 526 can be performed while minimizing negative effects on the other layers of coating system 524.

[0085] FIG. 5C illustrates a coated substrate 540 comprising a glass substrate 542 and coating system 544. The coating system 544 comprises multiple coating layers comprising two silver layers 546, 548 embedded within various other layers. The coated substrate 540 is an example of a double-low-E or low-E.sup.2 product which can also be seen as having solar absorbing properties.

[0086] As illustrated in FIG. 5C, the coated substrate 540 comprises the following layers: Glass/TiO.sub.x/ZnO.sub.x/Ag/ZnO.sub.x/ZnSnO.sub.x/ZnO.sub.x/Ag/ZnO.sub.x/TiO.sub.x/ZnSnO.sub.x. Instead of ZnSnO.sub.x, TiN could be used. The upper ZnSnO.sub.x layer could be covered or replaced by SiO.sub.x or Si.sub.3N.sub.4 or TZO (tin-doped zinc oxide) as illustrated with the configuration of FIG. 5B. The ZnO.sub.x layers can for example have a thickness between 1 nm and 10 nm. The silver layers 546, 548 can each have a thickness between 1 nm and 20 nm, preferred between 5 nm and 16 nm. According to a specific configuration, the thickness of silver layer 546 may be around 8 nm, while the thickness of silver layer 548 may be less, and may be around 1 nm to below 8 nm.

[0087] Surprisingly it has been found that when employing a short pulsed laser with pulses shorter than 1 microsecond for simultaneously tempering the silver layers 546 and 548, one or more of the effects of the invention as discussed above can be achieved. In particular, a desired annealing of the silver layers 546 and 548 can be performed while minimizing negative effects on the other layers of coating system 544.

[0088] FIG. 5D illustrates in part a coated substrate 560 comprising a glass substrate 562 and coating system 564. The coating system 564 comprises multiple coating layers comprising a silver layer 566 embedded within various other layers. The coated substrate 560 is an example of a low-E product provided with an additional absorber layer 568.

[0089] As illustrated in FIG. 5D, the coated substrate 560 comprises the following layers: Glass/SiO.sub.x (and/or Si.sub.3N.sub.4)/NiCr/SiO.sub.x/TiO.sub.x/Ag/ . . . , wherein the layers above the silver layer 566 can be selected, for example, similar to the layers covering silver layer 526 in FIG. 5B. Ignoring the barrier layers SiO.sub.x, the absorber layer 568 can be positioned near to the glass substrate 562, as illustrated in FIG. 5D, and/or an absorber layer can be located at another position in a coating system. Instead of NiCr, other absorber materials may be used for the absorber layer 568, e.g. Cr, CrN, TiN, TiC (or absorbing oxides or suboxides of any one or more of these metals), and/or another Ni alloy may be employed.

[0090] Surprisingly it has been found that when employing a short pulsed laser with pulses shorter than 1 microsecond for tempering the silver layer 566, one or more of the effects of the invention as discussed above can be achieved.

[0091] According to one embodiment, the coating system 544 of FIG. 5C may be added with an absorber layer such as absorber layer 568 shown in FIG. 5D to arrive at a low-E.sup.2 product with distinct solar absorbing properties.

[0092] A coating system such as system 524 of FIG. 5B may be deposited two times on a substrate to arrive at a double silver, low-E.sup.2 product similar to system 544 of FIG. 5C. According to other embodiments, a coating system such as system 524 of FIG. 5B may be deposited three times to arrive at a triple silver product. Some of these embodiments may comprise additionally an absorber layer such as absorber layer 568 shown in FIG. 5D to arrive at a combined triple silver and absorber product.

[0093] According to modifications of the various above embodiments, there may be a seed layer positioned below each of one or more of the silver-comprising layers for facilitating growth of the corresponding silver-comprising layer. Additional layers may be provided, for example one or more top layers, and/or titanium-containing layers.

[0094] Any of the layers described herein may comprise multiple sublayers. For example, one dielectric layer may comprise several sublayers, e.g. a combination of two sublayers TiO.sub.2/SiO.sub.2.

[0095] According to various embodiments, a coating layer may implement more than one function. For example, a layer comprising Si.sub.3N.sub.4 can function as a barrier layer and at the same time as a dielectric layer with medium refractive properties.

[0096] While many of the embodiments described herein relate to products intended for some degree of transparency, the invention is equally applicable to the manufacture of mirrors and other kind of reflecting structures which may include one or more silver-comprising layers.

[0097] While the invention has been described in relation to its preferred embodiments, it is to be understood that this description is intended non-limiting and for illustrative purposes only. In particular, various combinations of features wherein the features have been described separately hereinbefore are apparent as advantageous or appropriate to the skilled artisan.