ATOMIC LAYER DEPOSITION APPARATUS AND ATOMIC LAYER DEPOSITION METHOD

Abstract

An atomic layer deposition apparatus for forming an atomic layer on a flexible substrate, the apparatus including an unwinding chamber having an unwinding roll for unwinding the flexible substrate, a winding chamber having a winding roll for winding the flexible substrate on which the atomic layer is formed, a plurality of reaction chambers provided between the unwinding chamber and the winding chamber so that the flexible substrate can pass therethrough, a first supply part for storing a gas containing a first precursor, a first supply pipe connected to the first supply part, a second supply part for storing a purge gas, a second supply pipe connected to the second supply part, a third supply part for storing a gas containing a second precursor, a third supply pipe connected to the third supply part, and an exhaust pipe connected to the plurality of reaction chambers.

Claims

1. A spatial atomic layer deposition method comprising: moving a flexible substrate through a plurality of reaction chambers, wherein the plurality of reaction chambers comprises a first reaction chamber and a second reaction chamber, wherein the method further comprises performing atomic layer deposition comprising performing a first atomic layer deposition cycle on the flexible substrate in the first reaction chamber and then performing a second atomic layer deposition cycle on the flexible substrate in the second reaction chamber, the first atomic layer deposition cycle comprises exposing the substrate to a first exposure amount of a first atomic layer deposition precursor and the second atomic layer deposition cycle comprises exposing the substrate to a second exposure amount of the first atomic layer deposition precursor, the first exposure amount of the first atomic layer deposition precursor is greater than the second exposure amount of the first atomic layer deposition precursor.

2. The method of claim 1, wherein the substrate is a flexible PET substrate.

3. The method of claim 2, wherein the first atomic layer deposition precursor comprises trimethylaluminum.

4. The method of claim 1, wherein a speed of the moving of the flexible substrate is constant in each of the plurality of the reaction chambers is constant and a residence time of the flexible substrate in each of the plurality of the reaction chambers.

5. The method of claim 4, wherein the plurality of reaction chambers further comprises a third reaction chamber and said performing atomic layer deposition further comprises performing a third atomic layer deposition cycle on the flexible substrate in the third reaction chamber, wherein the third atomic layer deposition cycle comprises exposing the substrate to a third exposure amount of the first atomic layer deposition precursor, the third exposure amount of the first atomic layer deposition precursor is less than the second exposure amount of the first atomic layer deposition precursor.

6. The method of claim 5, wherein the plurality of reaction chambers further comprises one or more fourth reaction chamber and said performing atomic layer deposition further comprises performing a fourth atomic layer deposition cycle on the flexible substrate in the one or more fourth reaction chamber, wherein the fourth atomic layer deposition cycle comprises exposing the substrate to a fourth exposure amount of the first atomic layer deposition precursor in each of the one or more fourth reaction chamber, the fourth exposure amount of the first atomic layer deposition precursor is less than the third exposure amount of the first atomic layer deposition precursor.

7. The method of claim 3, wherein the plurality of reaction chambers further comprises a fifth reaction chamber adjacent to the first reaction chamber, wherein the trimethylaluminum physically adsorbed on the substrate in the first atomic layer deposition cycle in the first reaction chamber is removed from the substrate by a purge gas in the fifth reaction chamber.

8. The method of claim 3, wherein the plurality of reaction chambers further comprises a sixth reaction chamber after the first reaction chamber but before the second reaction chamber along the movement of the substrate, wherein the performing atomic layer deposition further comprises exposing the flexible substrate to plasma in the sixth reaction chamber so that a first atomic layer is formed from the trimethylaluminum chemically adsorbed on the substrate in the first atomic layer deposition cycle.

9. The method of claim 8, wherein the plurality of reaction chambers further comprises a seventh reaction chamber after the second reaction chamber in the direction of the substrate movement, wherein the performing atomic layer deposition further comprises exposing the flexible substrate to plasma in the seventh reaction chamber so that a second atomic layer is formed from the trimethylaluminum chemically adsorbed on the substrate in the second atomic layer deposition cycle.

10. The method of claim 3, wherein the plurality of reaction chambers further comprises a third reaction chamber after the second reaction chamber in the direction of the substrate movement, wherein the performing atomic layer deposition further comprises exposing the substrate to a second precursor gas in the third reaction chamber.

11. The method of claim 10, wherein the second precursor gas comprises TiCl.sub.4.

12. A spatial atomic layer deposition method comprising moving a flexible substrate through a plurality of reaction chambers, wherein the plurality of reaction chambers comprises a first reaction chamber and a second reaction chamber, wherein the method further comprises performing atomic layer deposition comprising performing a first atomic layer deposition cycle on the flexible substrate in the first reaction chamber and then performing a second atomic layer deposition cycle on the flexible substrate in the second reaction chamber, the first atomic layer deposition cycle comprises exposing the substrate to a first atomic layer deposition precursor and the second atomic layer deposition cycle comprises exposing the substrate to a second atomic layer deposition precursor.

13. The method of claim 12, wherein the substrate is a flexible PET substrate.

14. The method of claim 13, wherein the first atomic layer deposition precursor comprises trimethylaluminum.

15. The method of claim 14, wherein the second precursor gas comprises TiCl.sub.4.

16. The method of claim 14, wherein the second precursor gas comprises tris(dimethylamino)silane.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] FIG. 1 A schematic diagram showing the internal structure of an atomic layer deposition apparatus according to a first embodiment of the present invention.

[0032] FIG. 2 A schematic diagram showing the internal structure of the atomic layer deposition apparatus according to the first embodiment of the present invention viewed from a direction different from that of FIG. 1.

[0033] FIG. 3 A functional block diagram of the atomic layer deposition apparatus according to the first embodiment of the present invention.

[0034] FIG. 4 A diagram which illustrates an example of the gas conditions in the respective reaction chambers.

[0035] FIG. 5 A diagram which illustrates an example of the gas conditions in the respective reaction chambers.

[0036] FIG. 6 A schematic diagram showing the internal structure of an atomic layer deposition apparatus according to a second embodiment of the present invention.

[0037] FIG. 7 A schematic diagram showing the internal structure of a modified example of the atomic layer deposition apparatus according to the second embodiment of the present invention.

[0038] FIG. 8 A table showing an example of setting of the reaction chambers in the atomic layer deposition apparatus according to the first and second embodiments of the present invention.

[0039] FIG. 9 A table showing another example of setting of the reaction chambers.

[0040] FIG. 10 A table showing another example of setting of the reaction chambers.

[0041] FIG. 11 A table showing another example of setting of the reaction chambers.

[0042] FIG. 12 A schematic diagram showing the inside of reaction chambers in a modified example of the atomic layer deposition apparatus according to the first and second embodiments of the present invention.

[0043] FIG. 13 A schematic diagram showing the inside of reaction chambers in another modified example.

[0044] FIG. 14 A schematic diagram showing the internal structure of a modified example of the atomic layer deposition apparatus according to the first and second embodiments of the present invention.

DESCRIPTION OF REPRESENTATIVE EMBODIMENTS

[0045] However, it will be understood that the present invention is not limited to these embodiments. These embodiments are intended to be representative of the present invention.

[0046] With reference to FIGS. 1 to 5, a first embodiment of the present invention will be described. FIG. 1 is a schematic diagram showing the internal structure of an atomic layer deposition apparatus 1 according to the present embodiment viewed from a lateral side. The atomic layer deposition apparatus 1 forms a thin film by depositing an atomic layer by SALD on the surface of a flexible substrate 2 using a roll-to-roll (RTR) technique.

[0047] The atomic layer deposition apparatus 1 includes an unwinding chamber 10, a winding chamber 30, and a plurality of reaction chambers 20. The flexible substrate 2 is fed out from the unwinding chamber 10. The flexible substrate 2 on which an atomic layer is deposited is wound in the winding chamber 30. The plurality of reaction chambers 20 is arranged between the unwinding chamber 10 and the winding chamber 30.

[0048] The unwinding chamber 10 includes an unwinding roll (unwinding member) 11. The unwinding roll 11 feeds out the flexible substrate 2. The flexible substrate 2, which is a target for formation of an atomic layer, is wound in a roll shape around the unwinding roll 11. As the unwinding roll 11 rotates, the flexible substrate 2 is fed out to the reaction chamber 20.

[0049] The winding chamber 30 includes a winding roll (winding member) 31. The winding roll 31 winds the flexible substrate 2 on which the atomic layer is deposited. As the winding roll 31 rotates, the flexible substrate 2 coming out from the reaction chamber 20 is wound by the winding roll 31.

[0050] The unwinding roll 11 and the winding roll 31 are driven to rotate synchronously so that slack, etc., do not occur in the flexible substrate 2. A driving source for driving rotation (not shown) may be provided in one of the unwinding roll 11 and the winding roll 31, or may be provided in both of them.

[0051] The reaction chambers 20 are provided in plural numbers so that the steps in one cycle of ALD can be performed by SALD. In the present embodiment, as shown in FIG. 1, nine reaction chambers in total, including a first reaction chamber 20A to a ninth reaction chamber 20I, are arranged in the transport direction of the flexible substrate 2.

[0052] FIG. 2 is a schematic diagram showing the internal structure of the atomic layer deposition apparatus 1 viewed from above. As shown in FIG. 2, three supply pipes, i.e., a first supply pipe 21, a second supply pipe 22, and a third supply pipe 23, are connected to each of the reaction chambers 20A to 20I. The first supply pipes 21 connected to the respective reaction chambers are joined in one on the upstream side, and are connected to a first supply part 26. The first supply part 26 stores a gas containing a first precursor (hereinafter also referred to as “first precursor gas”). The second supply pipes 22 connected to the respective reaction chambers are joined in one on the upstream side, and are connected to a second supply part 27. The second supply part 27 stores a purge gas. The third supply pipes 23 connected to the respective reaction chambers are joined in one on the upstream side, and are connected to a third supply part 28. The third supply part 28 stores a gas containing a second precursor (hereinafter also referred to as “second precursor gas”).

[0053] Each first supply pipe 21 connected to each reaction chamber has a valve 31a and a mass flow meter 32a. Each valve 31a can be switched between open and closed states. Each mass flow meter 32a is provided between each valve 31a and each reaction chamber. Similarly, each second supply pipe 22 connected to each reaction chamber has a valve 31b and a mass flow meter 32b. Further, each third supply pipe 23 connected to each reaction chamber has a valve 31c and a mass flow meter 32c.

[0054] In each of the reaction chambers 20A to 20I, an exhaust pipe 24 is connected to a side surface opposite to the side surface to which the supply pipes are connected. The exhaust pipes 24 connected to the respective reaction chambers are joined in one on the downstream side, and are connected to an exhaust pump 25.

[0055] Each exhaust pipe 24 connected to each reaction chamber has a valve 36 and a variable conductance valve 37. Each valve 36 can be switched between open and closed states. Each variable conductance valve 37 is provided between each valve 36 and each reaction chamber.

[0056] FIG. 3 is a functional block diagram of the atomic layer deposition apparatus 1. The atomic layer deposition apparatus 1 includes a control unit 40 and an interface unit 45. The control unit 40 controls the entire apparatus. The interface unit 45 is connected to the control unit 40.

[0057] The control unit 40 is connected to the valves 31a to 31c, the mass flow meters 32a to 32c, the valve 36, and the variable conductance valve 37, which are disposed in each of the reaction chambers 20A to 20I. The control unit 40 is configured to be able to independently control the opening and closing of each valve, and the opening degree thereof.

[0058] Moreover, a heater 38 is attached to each of the reaction chambers 20A to 20I. Each heater 38 is connected to the control unit 40. Accordingly, the control unit 40 is configured to be able to independently control the internal temperature of each reaction chamber. Further, the pump 25 for the exhaust pipes is also connected to the control unit 40.

[0059] The operation of the atomic layer deposition apparatus 1 of the present embodiment during use, which is configured as described above, will now be explained.

[0060] As a preparation process, a roll of the flexible substrate 2 is attached to the unwinding roll 11, and one end of the roll is made to advance into the reaction chamber 20A and sequentially pass through the reaction chambers 20A to 20I. Then, the one end coming out from the reaction chamber 20I is attached to the winding roll 31.

[0061] The material of the flexible substrate 2 is suitably determined depending on the laminate to be produced, and examples thereof include polyethylene terephthalate (PET) and the like.

[0062] Next, the precursor gases and the purge gas used in each of the supply parts 26 to 28 are prepared. For example, when atomic layer deposition of aluminum oxide is performed, for example, trimethylaluminum (TMA) and nitrogen can be used as the first precursor and the purge gas, respectively, and H.sub.2O can be used as the second precursor gas. When TMA and H.sub.2O are used as the precursors, sufficient gas pressure can be generally obtained in the supply parts even at room temperature.

[0063] Next, a user sets the atomic layer deposition apparatus 1 using the interface unit 45 to input, into the control unit 40, the types of precursor gas and purge gas used, the temperature of each reaction chamber, the type of gas introduced, the gas conditions such as partial pressure and flow rate, the transport speed of the flexible substrate 2, and the like. This setting input may be omitted when the type, conditions, etc., of the precursor gas and the purge gas used are already provided to the control unit 40 because, for example, they are fixed or the same as those in the previous operation.

[0064] When the setting is completed, the control unit 40 first activates the pump 25 to evacuate each reaction chamber, thereby forming a vacuum state. Subsequently, the heaters 38 are suitably operated to adjust the temperature condition of each of the reaction chambers 20A to 20I within the predetermined range. Known feedback control, etc., may be used for the temperature control.

[0065] The temperature of each reaction chamber is selected in consideration of the heat resistance of the flexible substrate 2, the reactivity of the precursors, the heat resistance (thermal decomposition temperature) of the precursors, and the like. For example, when the material of the flexible substrate 2 is PET, the heat-resistant temperature is 120° C. or less; thus, the temperature of each reaction chamber is set to around 100° C. Even when the temperature of each reaction chamber is 100° C., the reaction of ALD using TMA and H.sub.2O proceeds.

[0066] Subsequently, the control unit 40 controls the opening and closing of the valves and variable conductance valves connected to the respective reaction chambers, and adjusts the internal state of each reaction chamber based on the setting.

[0067] When the first precursor gas or the second precursor gas is supplied to a reaction chamber, the control unit 40 opens, for example, the corresponding valve 31a or 31c. In this state, while referring to the value of the corresponding mass flow meter 32a or 32c, the exhaust rate is adjusted by controlling the valve 36 and the variable conductance valve 37 of the corresponding exhaust pipe 24. The inside of the reaction chamber is thereby filled with the desired precursor gas, and the gas conditions of the precursor gas are adjusted within the set range.

[0068] When the purge gas is supplied to a reaction chamber, the control unit 40 opens, for example, the corresponding valves 31b and 36. In this state, while referring to the value of the corresponding mass flow meter 32b, the exhaust rate is adjusted by controlling the variable conductance valve 37 of the corresponding exhaust pipe 24, whereby the inside of the reaction chamber is filled with the purge gas, and the gas conditions of the purge gas are adjusted within the set range.

[0069] Due to the control of the control unit 40 described above, each of the reaction chambers 20A to 20I is adjusted to optimal exposure conditions in the assigned step of ALD. In this state, the flexible substrate 2 is transported from the unwinding chamber 10 to the winding chamber 30 at the predetermined desired rate. Each step of SALD is thereby performed on the flexible substrate 2. Consequently, an atomic layer made of a desired material is deposited on the flexible substrate 2. After the atomic layer deposition is completed, the flexible substrate 2 is sequentially wound by the winding roll 31.

[0070] In the atomic layer deposition apparatus 1 according to the present embodiment, each of the plurality of reaction chambers 20A to 20I includes the first supply pipe 21, the second supply pipe 22, and the third supply pipe 23. This makes it possible to use each reaction chamber as a reaction space of the first precursor or the second precursor, and to use each reaction chamber as a space for purging. Accordingly, the atomic layer deposition apparatus 1 can suitably correspond to combinations of various precursors and cycle configurations; thus, a highly versatile apparatus can be formed.

[0071] Further, the supply pipes 21 to 23 provided in each reaction chamber are provided with, respectively, the valves 31a to 31c and the mass flow meters 32a to 32c. Moreover, each exhaust pipe 24 is provided with the valve 36 and the variable conductance valve 37. The control unit 40 is thereby configured to be able to independently set the gas conditions in each reaction chamber. As a result, for example, the reaction chambers to which the same gas is introduced can be adjusted to different gas conditions by changing the partial pressure, flow rate, etc., depending on, for example, the number of cycles that have been performed. Consequently, the exposure conditions of each step in SALD can be easily controlled, and film formation by ALD can be preferably performed.

[0072] Furthermore, the atomic layer deposition apparatus 1 is advantageous in that the time to perform each step can be easily adjusted.

[0073] In the example shown in FIG. 4, the purge gas is supplied to the reaction chambers 20A, 20C, 20E, 20G, and 20I, the first precursor gas is supplied to the reaction chambers 20B and 20F, and the second precursor gas is supplied to the reaction chambers 20D and 20H. This results in a configuration in which two cycles of ALD are performed by one transport operation. In FIG. 4, the gases supplied to the reaction chambers are expressed as patterns.

[0074] In the state shown in FIG. 4, for example, when the gas supplied to the reaction chamber 20A is changed to the first precursor gas, the configuration of the reaction chambers is as shown in FIG. 5. In the configuration shown in FIG. 5, two cycles are performed by one transport operation, as in FIG. 4; however, the reaction step of the first precursor in the first cycle is carried out for a time twice as long as that of the configuration of FIG. 4. Thus, the atomic layer deposition apparatus 1 allows, not only the gas conditions to vary for each reaction chamber, but also the exposure time of each step to be easily controlled.

[0075] Next, with reference to FIGS. 6 and 7, the second embodiment of the present invention will be described. The atomic layer deposition apparatus according to the present embodiment differs from the atomic layer deposition apparatus 1 of the first embodiment in the arrangement of a plurality of reaction chambers. In the following explanation, the same reference signs are assigned to structures common in those already explained above, and the duplicated description is omitted.

[0076] FIG. 6 is a schematic diagram showing the internal structure of an atomic layer deposition apparatus 101 according to the present embodiment viewed from a lateral side. In the atomic layer deposition apparatus 101 according to the present embodiment, a plurality of reaction chambers is repeatedly arranged in the vertical direction, as shown in FIG. 6. More specifically, a flexible substrate 2 unwound from an unwinding roll 11 first enters a reaction chamber a1 provided on the upper side of the apparatus. The direction of the flexible substrate 2 entering the reaction chamber a1 is changed by a guide roller 102, and the flexible substrate 2 is moved to a reaction chamber a2 located below the reaction chamber a1. Thereafter, the flexible substrate 2 enters a reaction chamber a3 located below the reaction chamber a2, its direction is changed by a guide roller 102 in the reaction chamber a3, and the flexible substrate 2 heads toward an upper reaction chamber a4.

[0077] Thus, the flexible substrate 2 is moved toward the winding chamber 30 passing through the reaction chambers, while being repeatedly transported upward and downward by the guide rollers 102. In order to minimize the influence on the formed atomic layer, each guide roller 102 is placed so as to be in contact with only both ends of the flexible substrate 2 in the width direction, which is perpendicular to the transport direction.

[0078] Although not shown in FIG. 6 for simplicity reasons, all the reaction chambers, including the reaction chamber a1 that communicates with the unwinding chamber 10 to the reaction chamber a27 that communicates with the winding chamber 30, each include three supply pipes 21 to 23 each provided with a valve and a mass flow meter, and an exhaust pipe 24 provided with a valve and a variable conductance valve. Further, although not shown, the atomic layer deposition apparatus 101 includes a control unit 40 and an interface unit 45 as with the first embodiment.

[0079] In the atomic layer deposition apparatus 101 according to the present embodiment, the exposure conditions of each step in SALD can also be easily adjusted, as in the atomic layer deposition apparatus 1 according to the first embodiment.

[0080] Moreover, because each of the plurality of reaction chambers includes the guide roller 102, even when the reaction chambers are arranged in a zigzag order in the vertical direction, SALD can be carried out while preferably allowing the flexible substrate 2 to pass through the reaction chambers by appropriately changing the transport direction of the flexible substrate 2. Furthermore, an increase in the size of the apparatus can be prevented.

[0081] In the present embodiment, reaction chambers positioned in the upstream and downstream sides of one reaction chamber are positioned above or below. Accordingly, it is highly possible that a gas supplied to a certain reaction chamber enter other communicating reaction chambers due to the difference in specific gravity, etc. In order to appropriately prevent this possibility, the control unit 40 may be set so that the internal pressure of the reaction chamber to which the purge gas is supplied is higher than the internal pressure of the reaction chambers to which the first precursor gas and the second precursor gas are supplied. Alternatively, the communication passages of the reaction chambers may be provided with flap-like entrance prevention parts for preventing the movement of gas between the reaction chambers. Furthermore, the internal pressure control mentioned above and the entrance prevention parts may be used in combination.

[0082] Such gas entrance preventive measures may also be carried out in the first embodiment in which the flexible substrate is transported horizontally.

[0083] Moreover, as in the modified example shown in FIG. 7, three or more reaction chambers may be arranged in the vertical direction to form a structure including more reaction chambers a1 to a57. In FIG. 7, five reaction chambers are arranged in the vertical direction; however, the number of reaction chambers arranged in the vertical direction may be, for example, two, four, or other even number.

[0084] The following explains, using a plurality of examples, an embodiment of SALD using the atomic layer deposition apparatus according to the above embodiment of the present invention, and setting of each reaction chamber for performing the SALD.

Setting Example 1

[0085] Setting Example 1 is an example of forming an atomic layer made of aluminum oxide on a flexible PET substrate by plasma ALD using the atomic layer deposition apparatus 101.

[0086] In Setting Example 1, TMA, nitrogen, and oxygen are used as a first precursor, a purge gas, and a second precursor, respectively.

[0087] Among a plurality of reaction chambers a1 to a27, TMA is introduced into each of the reaction chambers a1, a5, a9, a13, a17, a21, and a25. Oxygen is introduced into each of the reaction chambers a3, a7, all, a15, a19, a23, and a27. Plasma electrodes, not shown, are previously disposed in the reaction chambers into which oxygen is introduced, and oxygen plasma is generated before the start of SALD. The plasma electrodes may be previously disposed in all of the reaction chambers, and only the plasma electrodes in the reaction chambers to which oxygen is supplied may be energized.

[0088] Nitrogen is introduced into each of the rest reaction chambers a2, a4, a6, a8, a10, a12, a14, a16, a18, a20, a22, a24, and a26.

[0089] When the flexible substrate 2 is fed out from the winding chamber in this state, TMA is first chemically adsorbed on the surface of the flexible substrate 2 in the reaction chamber a1. Subsequently, in the reaction chamber a2, TMA physically adsorbed on the flexible substrate 2 is removed from the flexible substrate 2 by nitrogen, which is the purge gas. Further, in the reaction chamber a3, TMA chemically adsorbed on the flexible substrate 2 is exposed to oxygen plasma, and an atomic layer of aluminum oxide is formed by deposition. When excess oxygen is removed in the reaction chamber a4, one cycle of SALD is completed. Then, the same process is repeated, and seven cycles of SALD are carried out on the flexible substrate 2 before the flexible substrate 2 reaches the winding chamber 30.

[0090] FIG. 8 is a table showing an example in which the gas conditions of the first precursor gas are changed for each reaction chamber in Setting Example 1. In the example shown in FIG. 8, the partial pressure of TMA is set to be the highest in the reaction chamber a1 of the first cycle, and the partial pressure is set to gradually decrease in the second and subsequent cycles. Since the transport distance (e.g., 0.3 meter (m)) and transport speed (e.g., 36 m/s) of the flexible substrate 2 are constant in each reaction chamber, the residence time of the flexible substrate 2 in each reaction chamber is the same. Therefore, the exposure amount (Langmuir (L)) represented by the product of partial pressure and residence time is set to be the highest in the reaction chamber a1, to decrease as the cycles progress, and to be constant in the fourth and subsequent cycles.

[0091] The atomic layer deposition apparatus according to the present embodiment can also easily perform such control.

[0092] (Setting Example 2)

[0093] Setting Example 2 is an example of changing the time required for each step in some of the reaction chambers to which the first precursor is supplied. The first precursor and the purge gas are the same as those of Setting Example 1, and H.sub.2O is used as the second precursor gas.

[0094] FIG. 9 is a table showing an example of setting of each reaction chamber in Setting Example 2. In the example shown in FIG. 9, a first precursor gas containing TMA as the first precursor is supplied to nine reaction chambers, i.e., the reaction chambers a1 to a9, which are connected to the unwinding chamber 10. Accordingly, the time of the chemical adsorption step of the first precursor in the first cycle is 0.5×9=4.5 seconds. The chemical adsorption steps in the second and subsequent cycles are performed using one reaction chamber under conditions in which the partial pressure is lower than that of the first cycle.

[0095] In the examples shown in FIGS. 8 and 9, the exposure amount of TMA in the first cycle is set to be larger than those in the second and subsequent cycles, thereby increasing the amount of TMA infiltrating into the flexible substrate 2, and also increasing the amount of TMA adsorbed thereon. As a result, TMA is reliably adsorbed to saturation on the surface of the flexible substrate, and a fine layer can be formed in the interface between the substrate and the atomic layer.

[0096] (Setting Example 3)

[0097] Setting Example 3 is an example of forming an atomic layer made of mixed oxide on a flexible PET substrate using the atomic layer deposition apparatus 101. In this example, two types of first precursors, i.e., TMA and titanium chloride (IV, TiCl.sub.4), are used. A mixed gas (Na+CO.sub.2) of nitrogen and carbon dioxide is used as the purge gas, and oxygen is used as the second precursor. That is, in this example, the purge gas contains the second precursor, and the second precursor is in a state made reactive by production of plasma.

[0098] FIG. 10 is a table showing an example of setting of each reaction chamber in Setting Example 3. In the example shown in FIG. 10, the flexible substrate 2 is first repeatedly moved in the reaction chambers of the first precursor and the purge reaction chambers to promote the infiltration and adsorption of TMA (reaction chambers a1 to a10). Thereafter, the flexible substrate 2 is sequentially moved to the reaction chamber of the first precursor gas (TMA), the reaction chamber of the purge gas, the reaction chamber of the first precursor gas (titanium(IV) chloride), and the reaction chamber of the purge gas. Plasma (N.sub.2+CO.sub.2 plasma) is generated in some of the reaction chambers of the purge gas, thereby performing an oxidation reaction of the first precursor while purging (reaction chambers all to a27). The step of purging and oxidation by N.sub.2+CO.sub.2 plasma can be carried out by increasing the size of the reaction chamber rather than the diffusion length of active species (atomic oxygen etc.) from the plasma electrode.

[0099] Due to the above setting, an atomic layer made of mixed oxide of aluminum oxide and titanium oxide can be deposited and formed on the flexible substrate 2.

[0100] (Setting Example 4)

[0101] Setting Example 4 is an example of changing one of the first precursors used in Setting Example 3. In this example, tris(dimethylamino)silane (3DMAS) is used in place of titanium(IV) chloride.

[0102] FIG. 11 is a table showing an example of setting of each reaction chamber in Setting Example 4. In the example shown in FIG. 11, a cycle is performed while sequentially moving the flexible substrate 2 through the first precursor gas (TMA), the purge gas (N.sub.2+CO.sub.2), purge and oxidation (N.sub.2+CO.sub.2 plasma), the purge gas, the first precursor gas (3DMAS), the purge gas (N.sub.2+CO.sub.2), purge and oxidation (N.sub.2+CO.sub.2 plasma), and the purge gas. Here, two continuous reaction chambers are assigned in the 3DMAS adsorption step.

[0103] The exposure amount of 3DMAS required for saturated adsorption is generally larger than that of TMA; that is, 3DMAS requires a longer time for saturated adsorption at the same precursor partial pressure. Because more reaction chambers are assigned to 3DMAS than TMA, as in the example of FIG. 11, SALD using 3DMAS can be carried out without reducing the transport speed of the flexible substrate. In this example, aluminum oxide can be deposited for four cycles and silicon oxide can be deposited for three cycles, using the atomic layer deposition apparatus 101. When an apparatus including a larger number of reaction chambers, as shown in FIG. 7, is used, the number of cycles can be suitably increased.

[0104] In Setting Example 4, the oxidation reaction can also be promoted by assigning a plurality of reaction chambers to the step of purging and oxidation of 3DMAS.

[0105] Two types of first precursors are used in Setting Examples 3 and 4. Thus, when atomic layer deposition of ternary metal oxide is performed by the atomic layer deposition apparatus of the present invention using two types of first precursors (e.g., a first precursor A and a first precursor B), a fourth supply part and a fourth supply pipe may be provided so that, for example, the first precursor A is stored in the first supply part, and the first precursor B is stored in the fourth supply part. When ALD of a ternary metal oxide is performed, setting may be made so that the purge gas does not contain the second precursor.

[0106] The embodiments and setting examples of the present invention are explained above; however, the technical scope of the present invention is not limited to the above embodiments, and it is possible to change the combination of the components, add various modifications to each component, or delete the components, within a range that does not depart from the gist of the present invention.

[0107] For example, the above embodiments explain examples in which three supply pipes are provided in all the reaction chambers; however, not all of the plurality of reaction chambers have to include the all supply pipes. In one example, the reaction chamber adjacent to the unwinding chamber may not include the third supply pipe for supplying the second precursor gas. Further, two or more supply pipes may be connected to only some of the plurality of reaction chambers, although the degree of freedom of setting is reduced.

[0108] Moreover, the supply pipes of the plurality of reaction chambers are not necessarily connected to a single supply part. Therefore, each supply pipe may receive gas supply from a different supply part.

[0109] Moreover, the exhaust pipes are not necessarily provided in all of the reaction chambers, and may be provided only in some reaction chambers. However, in the case of a structure in which a plurality of reaction chambers shares one exhaust pipe, setting is preferably made so as to avoid the possibility that a plurality of precursors is present in the same reaction chamber due to the flow of the gas following discharge.

[0110] Furthermore, at least one of the plurality of reaction chambers may be configured to be detachable and attachable to thereby obtain a structure in which SALD can be carried out with minimum required reaction chambers depending on the specific contents, such as cycles and steps. Conversely, additional reaction chamber units that are configured to be detachable and attachable may be provided to obtain a structure that can accommodate an increase in the number of steps or cycles.

[0111] For example, in order to form an atomic layer having a thickness of about 10 to 20 nanometers (nm) by ALD, it is generally necessary to perform 100 or more cycles of ALD. Thus, when it is necessary to significantly increase the number of steps or cycles, the unwinding chamber and the winding chamber may be configured to be detachable and attachable, so that the atomic layer deposition apparatuses described above may be connected to each other. In the case of such a structure, when the unwinding chamber and the winding chamber are configured to also include a plurality of supply pipes, the exposure conditions can be set more easily.

[0112] As briefly mentioned in the above setting examples, plasma electrodes may be provided in some or all of the plurality of reaction chambers. When plasma active species are used as the second precursor, a plasma electrode 60 is disposed on only one side in the thickness direction of the flexible substrate 2, namely one surface side of the substrate, as shown in FIG. 12. Plasma active species 60a can thereby be concentrated on one surface side of the flexible substrate 2, and atomic layer deposition can be performed on only one side of the flexible substrate 2. When atomic layer deposition is performed on both surfaces of the flexible substrate 2, the plasma electrodes 60 may be disposed on both sides in the thickness direction of the flexible substrate 2, namely both surface sides of the substrate, as shown in FIG. 13,

[0113] When SALD is performed only by a structure in which the purge gas contains an element that functions as the second precursor, and plasma active species are used as the second precursor, the atomic layer deposition apparatus of the present invention may have a structure not including a third supply part and a third supply pipe.

[0114] Moreover, as in the modified example shown in FIG. 14, the atomic layer deposition apparatus may also be configured to include a plurality of reaction chambers 20 each provided with a guide roller 102, and a single purge chamber 103 connected to a second supply pipe and an exhaust pipe (not shown) and arranged to communicate with the plurality of reaction chambers 20. This structure can be used without any problem, for example, when the setting of gas conditions for purging is the same, although cycle forms that can correspond to this structure are slightly reduced; and the structure of the apparatus can be simplified.

[0115] In this modified example, only the first supply pipe and the third supply pipe may be connected to the plurality of reaction chambers 20, and the purge space may not be used.

[0116] Moreover, when a guide roller is provided in each reaction chamber, the guide roller may be movably placed in the reaction chamber. In this case, it is possible to finely regulate the transport distance in each reaction chamber, and it is also possible to make more detailed settings than the setting by assignment of reaction chambers.

[0117] In addition to the above, the unwinding chamber may be configured to enable plasma treatment by glow discharge. Moreover, the winding chamber may be configured in such a manner that other layers, such as an overcoat layer, can be formed on the formed atomic layer.

[0118] In place of the formation of an overcoat layer, etc., the winding chamber may be configured in such a manner that the substrate is wound around the winding roll after a protective film (inserting paper) is placed on the substrate surface, in order to protect the formed atomic layer thin film.

[0119] Furthermore, in the atomic layer deposition apparatus of the present invention, SALD can also be repeatedly performed by configuring the unwinding roll and the winding roll to be reversely rotatable. More specifically, after completion of the delivery from the unwinding roll, resetting is made in such a manner that the settings of the reaction chambers are arranged in the same manner from the winding chamber side. After completion of resetting the exposure conditions, the same SALD can be performed again by moving the flexible substrate from the winding chamber to the unwinding chamber. Here, when each reaction chamber is previously set so that the order from the unwinding chamber side and the order from the winding chamber side are the same, the step of resetting the exposure conditions is not necessary, and SALD can be continuously carried out more efficiently.

REFERENCE SIGNS LIST

[0120] 1, 101 . . . Atomic layer deposition apparatus; 2 . . . Flexible substrate; 10 . . . Unwinding chamber; 20, 20A, 20B, 20C, 20D, 20E, 20F, 20G, 20H, 20I . . . Reaction chamber; 21 . . . First supply pipe; 22 . . . Second supply pipe; 23 . . . Third supply pipe; 24 . . . Exhaust pipe; 26 . . . First supply part; 27 . . . Second supply part; 28 . . . Third supply part; 30 . . . Winding chamber; 60 . . . Plasma electrode; 102 . . . Guide roller; 103 . . . Purge chamber; a1, a2, a3, a4, a27, a57 . . . Reaction chamber.