JPH09307128A - Manufacturing equipment and method of thin film photoelectric transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To form a photoelectric conversion layer having high quality multilayered structure with height productivity by forming each thin film on a belt type flexible substrate wound up from one roll to the other roll. SOLUTION: In a stepping roll system which stops a substrate and form a film, an intermediate storing mechanism capable of storing substrates 1 for one frame, such as movable roll mechanism, is installed between a plurality of reaction chambers for film formation. The movable roll mechanism consists of, e.g. two carrying rolls 4 and a movable roll 5. Thereby the opening time of each reaction chamber can be shifted and mutual diffusion of reaction gas can be restrained, so that the conventional evacuation time for preventing mutual diffusion is made unnecessary. As a result, the tact time can be reduced by 17-20%. In a roll to roll film forming system which continuously forms a film while moving a substrate, mutual diffusion of reaction gas between reaction chambers is restrained and film quality is improved, by installing a valve mechanism 55 with a roll between the reaction chambers in which mechanism a movable roll mechanism 54 and gate valves 20 are combined.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for manufacturing a thin film photoelectric conversion element such as a solar cell using a flexible substrate.

[0002]

2. Description of the Related Art In recent years, a thin film photoelectric conversion element using an a-Si material such as amorphous silicon (hereinafter referred to as a-Si) or an a-Si alloy has been attracting attention as a photoelectric conversion element. In a typical solar cell as a thin-film photoelectric conversion element, cost reduction due to mass production is a major issue, and it is desired to greatly improve the production amount per unit time. Normally, the production volume of an a-Si solar cell is limited by the deposition apparatus for an a-Si film, but when a substrate with high rigidity such as glass is used, the substrate is placed in a tray with a relatively large heat capacity. It is necessary to mount it and form a film with a load lock type device. 1) Attaching and detaching the substrate to the tray, 2) Heating the substrate and tray, and 3) Mass production due to the reciprocation of the atmosphere and vacuum in the load lock chamber. It is difficult to significantly improve sex. Therefore, two types of film forming apparatuses using a flexible plastic film or stainless steel film as a substrate have been proposed.

One is, for example, K. Suzuki et al., "Technica
l Digest of the International PVSEC-1 ”(1984) p.
191 or by SROvshinsky on “Technical Di
gestof the International PVSEC-1 ”(1984) p.577
As described in, a flexible substrate is rolled into a roll-in chamber, a strip-shaped plurality of thin film photoelectric conversion elements are continuously formed through a plurality of reaction chambers, and the roll-out is rolled into the roll-out chamber. A "roll-to-roll" type film forming apparatus has been developed.

First, as an example of a thin film photoelectric conversion element having the simplest structure, FIG. 12 shows a single pin junction type a-Si.
The cross section of the solar cell is shown. In this solar cell, a metal film 21 is deposited on a resin film substrate 1 and then an a-Si n film is formed.
A layer 22, an i layer 23, and a p layer 24 are formed, and ITO (indium tin oxide) is formed thereon as a transparent conductive film 25.

FIG. 10 is a cross-sectional view of a roll-to-roll type film forming apparatus for forming a single pin junction type a-Si solar cell having the cross section shown in FIG. On the surface of the strip-shaped flexible substrate 1 which is unwound from the delivery roll 2 of the feed chamber 26 and continuously wound onto the take-up roll 3 of the take-up chamber 27 by passing over the transport roll 4, One reaction chamber 11, second reaction chamber 12, third reaction chamber 13
RF electrode 51 to which a high frequency is applied when sequentially passing through
The reaction gas is decomposed by the plasma generated between the electrode and the ground electrode 52 having the heater 6 to form an a-Si layer. For example, in the first reaction chamber 11, silane (SiH ₄ )
The n layer 22 is formed by using a gas as a main gas, a hydrogen (H ₂ ) gas as a diluent gas, and a phosphine (PH ₃ ) gas as a doping gas.
In the second reaction chamber 12, SiH ₄ is the main gas and H ₂ is the diluent gas for the i-layer 23. In the third reaction chamber 13, SiH ₄ is the main gas, H ₂ is the diluent gas, and diborane (B ₂ H ₆ ) gas is used. The p layer 24 is formed by continuous discharge using a doping gas, methane (CH ₄ ) or carbon dioxide gas (CO ₂ ) as a bandgap adjusting element. In this apparatus, the substrate 1 is sent at a constant speed, and film formation is performed during its movement. Sending room 2
The vacuum pump 7 is connected to each of the reaction chambers 11, 12, 13 and the winding chamber 27.

A gap 83 for passing the substrate 1 is provided on the wall separating the reaction chambers, but the gap 83 is narrowed as much as possible in order to suppress the mutual diffusion of the source gases as much as possible, and further the vacuum is provided. An intermediate chamber 10 having a pump 7 is provided. As another manufacturing device, Y. Ichikawa et al., “IEEE 1st World Conference on Photovoltaic En
A “stepping roll” type film deposition apparatus has been developed, which is described in “ergy Conversion” (1994) p.441 and alternately repeats stepwise substrate transport and film deposition.

FIG. 11 is a sectional view of a stepping roll type film forming apparatus for forming a single pin junction type a-Si solar cell as shown in FIG. 12, for example. There are four reaction chambers 11, 12, 13, 14 in a large vacuum common chamber 9 equipped with a vacuum pump 7, and each reaction chamber has
The RF electrode 51 and the ground electrode 52 having the heater 6 for heating the substrate face each other.

The strip-shaped flexible substrate 1 which has been wound around the delivery roll 2 is wound up on the winding roll 3 through the reaction rolls and the reaction chambers. The heater 6 is movable,
When the heater 6 moves upward in the drawing to open the reaction chamber, the substrate 1 can be transported, and when the heater 6 moves downward in the drawing and closes, the sealing material on the reaction chamber wall 8 is used. In the completely sealed state, an a-Si thin film is formed by plasma CVD. In the first reaction chamber 11, the n layer 22 of FIG.
However, the i layer 23 is formed in the second and third reaction chambers 12 and 13, and the p layer 24 is formed in the fourth reaction chamber 14. In this apparatus, film formation is performed with the flexible substrate 1 stopped. When the voltage application to the RF electrode 51 of each reaction chamber is stopped and the film formation is completed, each reaction chamber is evacuated and the ground electrode 52 and the sealing material of the reaction chamber wall 8 are separated from the substrate 1 One frame length is conveyed to the next position for forming the a-Si layer.
The unit length of the substrate used in one film formation, that is, the substrate transport pitch is one frame length. Usually, the film is not formed on the entire surface of the substrate without any gap, and one frame length is longer than the part where the film is formed in the reaction chamber. And in that case,
Separate film-formed portions are formed on the substrate, and non-film-formed portions remain between the film-formed portions. After that, heater closing → gas introduction → pressure control → discharge (film formation) → vacuum exhaust → heater open → one frame length conveyance is repeated as a sequence.

Since the grounded electrode 52 and the reaction chamber wall 8 provided with the sealing material on both sides are brought into close contact with the stopped substrate 1, the airtightness of the reaction chambers 31, 32 and 33 is maintained, so that the pressure in the reaction chamber is The film forming conditions can be controlled independently by a vacuum pump (not shown) connected to each. Further, by lowering the pressure of the common chamber 9 which is independently evacuated by the vacuum pump 7 from that of the reaction chambers 11, 12, 13, and 14, the reaction gas of the other reaction chambers or the atmospheric air enters each reaction chamber. Since this is prevented, it is possible to stack the multilayer films stepwise without mutual diffusion of gases.

In FIG. 11, there are two reaction chambers, i.e., the second and third reaction chambers 12 and 13, for forming the i-layer.
This is for forming the layer 22. The number of reaction chambers for the p, i, and n layers depends on the size of each process time,
The optimum value is set so that the takt time is short and the device cost is low. Further, when this method is adopted, there is an advantage that it is possible to form films having extremely different film forming conditions with the same apparatus. The ITO (indium.
It is desirable that the tin oxide) be continuously formed in the same device from the viewpoint of reducing the cost of the device and suppressing the leak caused by the pinhole after the a-Si film formation. However, since ITO is usually formed by sputtering, the type of discharge gas and the pressure during film formation are extremely different from the case of a-Si film formation, and in the roll-to-roll system in which the reaction chambers are connected through a narrow gap. Continuous formation was difficult. On the other hand, when the stepping roll method is adopted, each reaction chamber is completely partitioned during film formation, so that ITO can be formed in the same apparatus.

[0011]

In the case of the roll-to-roll type film forming apparatus, since the film is continuously formed in each reaction chamber, the wasteful time in the process is zero. However, the reaction chambers are connected by a narrow gap for passing the substrate, and it is difficult to completely suppress the mutual diffusion of the source gases. Therefore, a small amount of dopant may diffuse into the i-layer, which may deteriorate the characteristics of the solar cell. Furthermore, as described above, it is difficult to consistently form the same device up to steps such as ITO where the conditions such as the degree of vacuum greatly differ.

On the other hand, in the case of the stepping roll type film forming apparatus, since the reaction chamber is completely partitioned during film formation, mutual diffusion of gases is completely suppressed, and a highly efficient solar cell can be manufactured. It is also easy to consistently form ITO up to the same device. However, there is a dead time of 1 minute 30 seconds for each step (30 seconds for transportation, 30 seconds for gas introduction and pressure control, 30 seconds for vacuum evacuation), and the takt time is about 5 minutes or less. In the case of mass production by mass production, this dead time leads to a reduction in production capacity.

In view of the above problems, it is an object of the present invention to produce a thin film photoelectric conversion element capable of suppressing the mutual diffusion of source gases between reaction chambers, forming each layer under optimum conditions, and reducing the dead time. An object is to provide an apparatus and a manufacturing method.

[0014]

In order to solve the above-mentioned problems, the present invention provides a photoelectric conversion layer by stepwise laminating a plurality of thin films having different properties on a strip-shaped flexible substrate. In a stepping roll type manufacturing apparatus of a thin film photovoltaic element for forming a film, a substrate having a length that is an integral multiple of a unit length (one frame length) of the substrate used at one time during film formation is accumulated between reaction chambers. It shall have a possible intermediate storage mechanism.

As the intermediate accumulating mechanism, it is assumed that the substrate is deformed by a solid or gas pressing object in a direction substantially at right angles to the feeding direction for accumulating. If the intermediate storage mechanism is provided in this way, the opening time of the reaction chamber can be shifted due to the storage of the substrate. It is also possible to use a drive roll mechanism that accumulates the substrate by the difference in the rotation amount of the two feed rolls.

In particular, if a movable roll mechanism having a roll at the tip of the pressed object or a drive roll mechanism is used, the friction between the substrate and the roll can be suppressed. Further, if the substrate is deformed by a gas pressing object, or the substrate is deformed by gripping the substrate from the back surface with an electrostatic adsorption portion, contact between the substrate surface and other objects can be avoided.

Further, partition valves may be arranged on both sides of the storage mechanism to provide an intermediate chamber. If there is an intermediate chamber that is partitioned by a partition valve, invasion of reaction gas between the reaction chambers can be suppressed. In the stepping roll method of manufacturing the thin film photoelectric conversion element using the manufacturing apparatus as described above, the opening times of the plurality of reaction chambers are shifted.

In particular, it is preferable to shift the opening timing of the partition valves on both sides of the intermediate chamber. By doing so, mutual diffusion of gas between the reaction chambers can be suppressed. Further, in a roll-to-roll manufacturing apparatus for a thin film photoelectric conversion element, a plurality of thin films having different properties are continuously stacked on a strip-shaped flexible substrate while transporting the substrate to form a photoelectric conversion layer. It has a valve and an intermediate storage mechanism arranged in front of and behind it.

By doing so, the substrate can be accumulated and discharged by the intermediate accumulation mechanism, so that the opening time of the partition valve can be shortened. As the intermediate storage mechanism, the substrate is deformed by a solid or gas pressing object in a direction substantially perpendicular to the feed direction to perform storage. A feed roll mechanism that accumulates the substrate by the difference in the amount of rotation of the two feed rolls, a movable roll mechanism that has a roll at the tip of the pressed object, a gas pressing object, or a backside gripping mechanism for the substrate that has a suction part, etc. Is similar to the above case.

In particular, if a roll-equipped valve mechanism having an intermediate chamber partitioned by two partition valves and comprising at least three movable roll mechanisms arranged before and after the two partition valves is provided, the opening of the valve mechanism is possible. Stagger the timing. If an exhaust device for evacuating the intermediate chamber partitioned by the two partition valves is provided, the diffusion of the reaction gas can be suppressed.

In the roll-to-roll manufacturing method of the thin film photoelectric conversion element using the manufacturing apparatus as described above, it is assumed that there is a time during which part of the substrate remains stationary during film formation. In particular, in the case where there are two partition valves, it is preferable to shift the opening timing of those partition valves. By doing so, the partition valve can be closed at the portion of the substrate that is stationary during film formation, and the opening time can be shortened to suppress mutual diffusion of gases.

Further, in a thin-film photovoltaic device manufacturing apparatus in which a plurality of thin films having different properties are laminated on a strip-shaped flexible substrate to form a photoelectric conversion layer, a roll-to-roll system of continuous film formation is used. A reaction chamber and a stepping-roll system reaction chamber for forming a film stepwise on a stationary substrate are provided, and an intermediate storage mechanism is provided between them.

In particular, it is preferable to have a partition valve between the reaction chamber of the stepping roll system and the movable roll mechanism. By doing so, the movable roll mechanism accumulates the substrate,
Since it can be released, the substrate can be continuously transported between the two types of film forming apparatuses. If there is a partition valve between the reaction chamber of the stepping roll system and the movable roll mechanism, mutual diffusion of gases can be suppressed by closing the partition valve.

As a method of manufacturing a thin film photoelectric conversion element using the above manufacturing apparatus, some films are continuously formed by a roll-to-roll method while the substrate is being conveyed, and other films are stepping rolls. In this method, the substrate is stationary and the film is formed stepwise.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS To solve the above-mentioned problems, the present invention provides:
A method of providing an intermediate storage mechanism for the flexible substrate in the film forming apparatus was devised. As a concrete means, a movable roll or the like was incorporated, and the flexible substrate was accumulated by the operation thereof. Embodiments of the present invention will be described below with reference to the drawings in which the same parts as those in FIGS. [Embodiment 1] FIG. 1 is a sectional view of a stepping roll system film forming apparatus of a first embodiment of the present invention for forming a single pin junction type a-Si solar cell as shown in FIG. 12, for example. is there.

There are a first block 31, a second block 32 and a third block 33 which are large vacuum chambers each equipped with a vacuum pump 7. In the first block 31, the delivery roll 2 of the flexible substrate 1 and the first reaction chamber 11 are arranged in the second block 3
The second and third reaction chambers 12 and 13 are accommodated in the second block 2, and the fourth reaction chamber 14 and the winding roll 3 are respectively accommodated in the third block 33. An intermediate chamber 10 partitioned by a partition valve 20 is provided between the blocks, and the transport roll 4 as an intermediate storage mechanism and the flexible substrate 1 are provided in the intermediate chamber 10.
There is provided a movable roll mechanism including a movable roll 5 on the opposite side of the transport roll 4 with the sheet sandwiched therebetween.

An RF electrode 51 connected to a high frequency power source (not shown) and a ground electrode 52 having a heater 6 for heating the substrate face each reaction chamber, and a vacuum pump 7 is provided. The heater 6 is movable, and when the heater 6 rises to open the reaction chamber, the substrate can be transported, and when the heater 6 descends and closes, it is completely sealed by the sealing material on the reaction chamber wall 8. In this state, the a-Si thin film is formed by plasma CVD as in the example of FIG.

Next, the carrying operation of the stepping roll type film forming apparatus of the first embodiment of the present invention shown in FIG. 1 will be described with reference to FIG.
A description will be given below according to the explanatory diagrams of (a) to (g). Here, the n layer is formed in the first reaction chamber 11 and the second and third reaction chambers 1 are formed.
It is assumed that the i layer is deposited at 2 and 13. First reaction chamber 11
Then, from a gas supply device (not shown), SiH ₄ , H ₂ , P
H ₃ is always kept flowing as the source gas of SiH ₄ and H ₂ in the reaction chambers ₃ and ₄ , respectively, and film formation and substrate transfer are performed by repeating the following operations.

(A) Film formation is performed in all reaction chambers.
The substrate 1 is stationary, and each reaction chamber contains several hundred P of reaction gas.
The pressure is a. First block 31, in the second block are evacuated in large-capacity vacuum pump, 10 ^-3
The pressure is Pa. The partition valves 20a and 20b on both sides of the intermediate chamber 10 are both open, and the intermediate chamber is also in a high vacuum state. The movable roll 5 is separated from the substrate 1.

(B) The application of high frequency to the RF electrode 51 in the first reaction chamber 11 is stopped to stop the film formation. After closing the partition valve 20b on the right side, the heater 6 of the first reaction chamber 11 is raised to open the reaction chamber. At this time, the substrate 1 in the first block 31 also slightly rises and separates from the sealing material of the reaction chamber wall 8. Since SiH ₄ , H ₂ , and PH ₃ are kept flowing, the vacuum degree in the first block 31 is lowered, but not so much. Film formation may be continued in the second and third reaction chambers 12 and 13.

(C) The substrate 1 is fed from the delivery roll 2, the movable roll 5 is lowered, and the substrate 1 having a length of one frame is stored in the intermediate chamber 10. (D) The heater 6 of the first reaction chamber 11 is lowered to close the reaction chamber, the pressure is controlled, and then the discharge is started. The partition valve 20b on the right side of the intermediate chamber 10 is opened after the first block 31 becomes high vacuum.

(E) RF in the second and third reaction chambers 12 and 13
The application of high frequency to the electrode 51 is stopped and the film formation is stopped. After closing the partition valve 20a on the left side, the heaters 6 of the second and third reaction chambers 12 and 13 are raised to open the reaction chambers. At this time, the substrate 1 in the second block 32 also slightly rises and separates from the sealing material of the reaction chamber wall 8. Since SiH ₄ and H ₂ continue to flow, the degree of vacuum in the second block 32 decreases, but not so much. The first reaction chamber 11 may continue film formation.

(F) While raising the movable roll 5, the substrate 1 is fed for one frame length. (G) After lowering the heaters 6 of the second and third reaction chambers 12 and 13 to close the reaction chambers and adjusting the pressure, film formation is started. The partition valve 20a on the left side of the intermediate chamber 10 is the second block 32.
Open after the high vacuum. 2 illustrates the left half portion of the film forming apparatus of FIG. 1, the operation of the right half portion is the same and can be easily understood.

In the film forming apparatus as shown in FIG. 1, by providing a mechanism capable of accumulating the substrate 1 for one frame length by using the movable roll 5, it becomes possible to shift the opening times of the reaction chambers from each other. . Conventionally, since the reaction chambers are opened simultaneously, it is necessary to draw a vacuum in the common chamber once to avoid mutual diffusion of gases between the reaction chambers, but since the reaction chambers are opened at different timings, The reaction gas can be left flowing, eliminating the need to evacuate the common chamber.

Since the grounded electrode 52 and the reaction chamber wall 8 provided with the sealing material 81 on both sides are brought into close contact with the stopped substrate 1, the airtightness of each reaction chamber 11, 12, 13, 14 is maintained, so that the reaction chambers are kept. Can be independently controlled by an exhaust system 7 (not shown) connected to each of them, each film forming condition can be independently controlled, and each block 31, 32 exhausted independently by the exhaust system 15 can be controlled. , 33 to lower pressure than the reaction chambers, the reaction chambers 11, 12, 1
It is the same as in the conventional case that the reaction gas or the atmosphere in the other reaction chambers is prevented from entering the chambers 3 and 14.

Further, the intermediate chamber 1 equipped with a partition valve 20
If 0 is provided, the blocks are separated from each other, so that the isolation between the reaction chambers is enhanced, and the invasion of the reaction gas or the atmosphere in the other reaction chambers that affect each other is prevented. In the case of the conventional stepping roll type film forming apparatus shown in FIG. 11, there was a total of about 1 minute and 30 seconds per step (conveying 30 seconds, gas introduction and pressure control 30 seconds, vacuum evacuation 30 seconds). On the other hand, in this embodiment, the dead time is 4
It is shortened to about 5 seconds (conveyance 30 seconds, pressure control 15 seconds). The vacuum pump in the block during substrate transfer is normally full open, but the pressure may be controlled so that the pressure in the reaction chamber becomes the film formation pressure. In this case, the time required for pressure control after sealing the reaction chamber becomes 0, so that the dead time is only 30 seconds required for transportation.

Here, the film forming sequence and the tact time in the case of manufacturing the pin single junction type a-Si solar cell having the structure shown in FIG. 12 by using the stepping roll type film forming apparatus of FIG. 1 will be considered. First reaction chamber 11
And the n layer 22 is the i layer 23 in the second and third reaction chambers 12 and 13.
, And the p-layer 24 is formed in the fourth reaction chamber 14. The thickness of each layer of the a-Si solar cell to be manufactured is 15 for the n layer 22.
nm, the i layer 23 is 300 nm, and the p layer 24 is 12 nm. The deposition rate of each layer is 5 nm / min, 50 nm
/ Min, and 4 nm / min. In this case, the pure film formation time (discharge time) in the first reaction chamber 11 and the fourth reaction chamber 14 is 3 minutes. If the i layer 23 is formed in the second and third reaction chambers by 150 nm each, the pure film formation time is similarly 3 minutes. Based on the concept of the film forming method described above, the film forming sequence in Table 1 can be considered as an example.
According to this sequence, the takt time is 3 minutes and 45 seconds, the dead time is only 45 seconds required for the conveyance and the pressure control, and the ratio of the dead time to the entire takt time is 20%. Since the dead time of the conventional stepping roll device is about 1 minute 30 seconds, and the ratio of the total tact time is 33%, it can be seen that the ratio of the dead time is significantly reduced by the present invention.

[0038]

[Table 1]

Here, the transportation marked with * means from the opening of the heater 6 to the closing thereof. It is also possible to omit the partition valves 20 on both sides of the movable roll 5.
However, when the number of blocks is plural, the substrate 1 standing by on the movable roll 5 is exposed to an undesired gas, so that the characteristics may deteriorate when the solar cell is used.

The axes of the sending roll 2, the winding roll 3, and the transport roll 4, the RF electrode 51, and the ground electrode 52
If each surface is made vertical, it is possible to prevent the dust falling from the ceiling or wall surface of each reaction chamber 11 to 14 from adhering to the substrate or the film surface thereon. If the substrate 1 is arranged so as to face both sides of the RF electrode 51, two rolls can be formed simultaneously.
By doing so, the utilization efficiency of the raw material gas is high, and the productivity is further improved. Further, the RF electrode 51 and the ground electrode 52 can be reversed.

It goes without saying that the substrate 1 may be a stainless steel film. [Embodiment 2] FIG. 3 shows an example of a roll-to-roll type film forming apparatus according to a second embodiment of the present invention for producing a single pin junction type a-Si solar cell as shown in FIG. It is sectional drawing of a part.

There is a first reaction chamber 11 and a second reaction chamber 12 each equipped with a vacuum pump 7. In the first reaction chamber 11, there are the feed roll 2 of the flexible substrate 1, the ground electrode 52 and the RF electrode 51 having the heater 6, and the second reaction chamber 12 also has the ground electrode 52 having the heater 6. There is an RF electrode 51. An intermediate chamber 10 that can be partitioned by partition valves 20a and 20b between the first reaction chamber 11 and the second reaction chamber 12
There is. A movable roll mechanism 54 including the movable roll 5 and the transport roll 4 is provided on both sides of the partition valves 20a and 20b. A combination of the partition valve 20 and the movable roll mechanism will be referred to as a roll valve 55.

On the right side of the second reaction chamber 12, there is another reaction chamber (not shown) sandwiching a valve with a roll, and on the right side there is a take-up roll. Each reaction chamber is connected to a high frequency power source (not shown). The RF electrode 51 and the ground electrode 52 provided with the heater 6 for heating the substrate face each other, and the a-Si thin film is formed by plasma CVD, as in the example of FIG. A vacuum pump 7 is provided.

First, the valve 55 with a roll used in the roll-to-roll type film forming apparatus of the second embodiment of the present invention shown in FIG. 3 will be described below with reference to the operation explanatory diagrams of FIGS. 4 (a) to 4 (c). To do. This rolled valve 55 is the substrate 1
It is composed of a partition valve 20 for sandwiching and sealing it, two movable rolls 5 and four ordinary transport rolls 4.

During idling, the two movable rolls 5 do not move vertically, and the substrate 1 is conveyed at a speed V through the open partition valve 20a [FIG. 4 (a)]. When forming a film in the first reaction chamber 11, the partition valve 20a is closed. The substrate 1 is stopped by the partition valve 20a,
Since it is sent from the left side, the movable roll 5a on the left side of the partition valve 20a descends and accumulates the substrate 1. On the other hand, the movable roll 5b on the right side of the partition valve 20a rises and releases the accumulated substrate 1 [FIG. 4 (b)]. At this time, the left and right substrates 1 while maintaining the tension at a certain value.
Are moved at speed V. The discharge speed is the feed speed V of the substrate 1.
With this, the substrate 1 will not be loosened or torn off.

As a method of moving the movable rolls on both sides, the speed V /
There are two methods, a method of moving the substrate 1 at a speed of 2 and a method of moving the substrate 1 at a speed V from the outside to passively move the substrate 1 so as to keep the tension constant, but either method may be used. Partition valve 2
0a left movable roll 5a descends and accumulates a certain amount, then the partition valve 20a is opened, the left movable roll 5a is raised, the right movable roll 5b is lowered, and the substrate 1 is placed on the right side of the partition valve 20a. Move the accumulated amount of [Fig. 4
(C)]. When the gate valve is opened, the two movable rolls are moved at an appropriate speed and stopped when they return to the idling position. At this time, the moving speed of the substrate 1 can be made faster than the sending speed V from the sending roll 2.
Then, the time for opening the partition valve 20 can be shortened by the earlier amount. For example, if you make it 3 times faster, the opening time will be 1/3.

By using this valve mechanism, it is possible to intermittently partition the reaction chambers on both sides while keeping the substrate feeding speed on both sides constant. Returning again to the film forming apparatus of the second embodiment of FIG. 3, the manufacturing method thereof will be described. Since this film forming apparatus is basically a roll-to-roll type film forming apparatus, the feeding speed of the substrate from the feeding roll 2 is constant, and the feeding of the substrate does not stop unlike the stepping roll method. The film formation in each reaction chamber is also continuously performed. N layer in the first reaction chamber 11, second, third reaction chamber 12,
At 13, the i-layer is to be deposited. In the first reaction chamber 11, SiH ₄ , H ₂ and PH _{3 are} supplied from a gas supply device (not shown).
In the second reaction 2 chamber 12, SiH ₄ and H ₂ are continuously supplied as source gases. However, by using the valve with roll, when the partition valve 20 is closed, the substrate 1 is stopped at that portion, and the partition valve 20 is opened for a short time to rapidly feed the substrate 1. However, as described above, since the opening time of the partition valve 20 can be shortened, the mutual diffusion of the reaction gases in the reaction chambers 11 and 12 can be suppressed accordingly.

As a result, the characteristic deterioration of the solar cell due to the diffusion of the reaction gas, unlike the conventional roll-to-roll type film forming apparatus, is eliminated. In the example of the film-forming apparatus for manufacturing the a-Si solar cell of FIG. 3, 0.1 to 1 m of the resin film substrate 1 with the metal film is fed from the delivery roll 2.
It is assumed that the n-layer is produced in the first reaction chamber 11 and the i-layer is produced in the second reaction chamber 12 at a rate of / min. Two reaction chambers 1
Two partition valves 20a and 20b are provided between 1 and 12.
There is an intermediate chamber 10 which is partitioned by and has a vacuum pump 7. The two partition valves 20a and 20b operate in the sequence shown in Table 2.

[0049]

[Table 2]

As shown in FIG. 3, if there is an intermediate chamber 10 which can be partitioned by the partition valves 20a and 20b between the two reaction chambers 11 and 12, it is possible to prevent the two partition valves from opening simultaneously. It can be operated by a series of operations. If sufficient evacuation is performed while the two valves are closed at the same time, mutual diffusion of gas between the two reaction chambers 11 and 12 can be completely suppressed. That is, the greatest problem of the roll-to-roll film forming apparatus, gas mutual diffusion, can be overcome.

Since the stroke of the movable roll 5 is determined by the following equation, it is necessary to pay attention when designing the device. Stroke = Time when partition valve is closed × Film transport speed / 2 When the valve mechanisms 55 with rolls are provided on both sides of the intermediate chamber 10, the number of movable roll mechanisms 54 in the intermediate chamber 10 can be one. [Embodiment 3] FIG. 5 shows a partial sectional view of a manufacturing apparatus according to a third embodiment of the present invention. This is the a-Si layer 22, 2 of FIG.
This is a roll-to-roll type film forming apparatus for consistently and continuously forming films 3 and 24 and the transparent electrode 25. a-Si
Each layer has a first, second, and third reaction chamber 1 on a flexible substrate 1.
Nos. 1, 12, and 13 are omitted because the film is formed by a roll-to-roll film forming method by a normal plasma CVD method.

The fourth reaction chamber 14 is a sputtering chamber for forming a transparent electrode, 18 is an ITO target, and 19 is an anode. The intermediate chamber 10 was provided at the boundary between the third reaction chamber 13 and the fourth reaction chamber 14, and the valve mechanism 55 with rolls having the partition valves 20c and 20d was arranged. 6 is a heater. While each a-Si layer is formed by plasma CVD in the range of 10 to 100 Pa using SiH ₄ gas as a main gas H ₂ as a diluent gas, the transparent electrode is made of ITO (indium tin oxide) as a raw material and an argon gas (Ar). ) Is used as a sputtering gas at a pressure of 0.1 to 1 Pa by sputtering. Therefore, the process gas and the pressure are extremely different in both reaction chambers, and the conventional roll-to-roll method cannot form a film.

In this embodiment, the third reaction chamber 13 for plasma CVD for forming an a-Si layer and the fourth reaction chamber 14 for ITO sputtering are partitioned by two sets of valve mechanisms 55 with rolls. There is. Two partition valves 20c, 20
By shifting the opening time of d, the fourth reaction chamber 14 can be kept at a high degree of vacuum. As a result, it became possible to form the ITO film by a roll-to-roll method. In addition, ITO
May be formed by vapor deposition, and a valve mechanism with a roll may be applied to all the intermediate chambers. [Embodiment 4] FIG. 6 shows a partial sectional view of a manufacturing apparatus according to a fourth embodiment of the present invention. This is, for example, a of the solar cell of FIG.
A film forming apparatus in which a roll-to-roll method and a stepping roll method for forming a Si layer are mixed.

There are a first reaction chamber 11 equipped with a vacuum pump 7, a first block chamber 31 accommodating the second and third reaction chambers 12 and 13, and a fourth reaction chamber 14. Each reaction chamber has a ground electrode 52 equipped with a heater 6 and an RF electrode 51 for film formation by the plasma CVD method, but in the first reaction chamber 11 and the fourth reaction chamber 14, a roll-to-roll method, that is, a substrate is used. While moving 1, the film formation is performed in the second and third reaction chambers 12 and 13 by the stepping roll method, that is, with the substrate 1 stopped.

Between the first reaction chamber 11 and the first block 31 and between the first block 31 and the fourth reaction chamber 14,
The partition valve 20 and a valve mechanism 55 with a roll having a movable roll mechanism 54 on both sides thereof are arranged. Partition valve 2 between the first reaction chamber 11 and the first block 31
0a and the movable rolls 5a and 5b on both sides thereof are operated as follows. The film formation in the first reaction chamber 11 is continuously performed. When the partition valve 20a is closed, the movable roll 5a is lowered to accumulate the substrate 1. When the accumulated amount reaches one frame length, the partition valve 20a is opened, the movable roll 5a is raised and the movable roll 5b is lowered, and the accumulated amount of the substrate 1 is transferred to the right side of the partition valve 20a. Partition valve 20
After closing a, the heater 6 in the second and third reaction chambers 12 and 13 is closed.
And raise the substrate 1. After one frame has been sent, the heater 6 is lowered to adjust the pressure, and the second and third reaction chambers 12 and 13 are
Then, the film formation is started.

The operation of the valve mechanism with roll 55 between the first block 31 and the fourth reaction chamber 14 is also proceeded in the same manner.
A smooth transition can be made from the stepping roll film formation method to the roll-to-roll film formation method. In this way, even a film forming apparatus in which the roll-to-roll method and the stepping roll method are mixed can smoothly perform film formation, and a film formation layer making use of the characteristics of each method can be obtained. Moreover, the partition valve 2
By shifting the opening time of 0 and the opening time of the second and third reaction chambers 12 and 13 from each other, mutual diffusion of gas between the reaction chambers can be suppressed.

The partition valves 2 are provided at both ends of the first block 31.
If 0b is provided and the opening time with respect to the partition valve 20a is shifted, the isolation between the reaction chambers can be further enhanced, and the film chamber for film formation can be enhanced. Although only the reaction chamber for forming the a-Si layer is shown in the figure, an ITO sputtering chamber may be provided.

In the above embodiments, the movable roll mechanism is used as the intermediate accumulating mechanism, but other mechanisms are possible. 7A and 7B show a drive roll mechanism 56 using two sets of drive rolls 16. The substrate 1 is accumulated and discharged by changing the rotation amounts of the two sets of drive rolls 16. If the first drive roll 16a is rotated and the second drive roll 16b is stopped or rotated less than the first drive roll 16a, the substrate 1 is accumulated between them, and conversely, the first drive roll 16a is stopped, The discharge is performed by rotating the second drive roll 16b.

Holding between the drive rolls 16a and 16b and the substrate 1 is performed by friction [FIG. 7 (a)], or the protrusions of the drive rolls 16a and 16b are inserted into the hole rows provided at the ends of the substrate 1. Perform [FIG. 7 (b)]. These methods are for substrate 1
It is possible to send out positively. FIG. 8 is another example of the intermediate storage mechanism. Instead of pushing the substrate with the movable roll, the nozzle 28 at the upper part of the drawing ejects an inert gas for a short time to deform the substrate 1 for storage. It is a thing. If necessary, a stopper 29 may be provided below. In the method of deforming the substrate with the movable roll, the roll comes into contact with both sides of the substrate, and although the friction of the roll causes little friction, the surface of the substrate may be scratched. With the pressing method, the surface of the substrate 1 can be deformed without contact.

FIG. 9 is an example of yet another intermediate storage mechanism. Instead of pushing the substrate with a movable roll, there is an electrostatic attraction plate 17 at the bottom of the drawing, which is brought into contact with the back surface of the substrate 1 to attract the substrate and then moved obliquely downward for accumulation. As the electrostatic attraction plate 17, an alumina plate having electrodes embedded therein is known. Also in this case, the substrate can be deformed without coming into contact with the surface of the substrate 1.

[0061]

As described above, according to the present invention, the intermediate storage mechanism such as the movable roll mechanism can store or release the margin of the flexible substrate to provide the portion where the substrate is stationary. . In the stepping roll type film forming apparatus, by providing the intermediate storage mechanism and shifting the opening timing of the plurality of reaction chambers, the dead time for not forming the film can be reduced to about half as compared with the conventional apparatus. This effect remarkably appears especially when the takt time becomes short, and the productivity can be greatly improved.

On the other hand, it becomes possible to suppress mutual diffusion of gases, which has been impossible in the conventional roll-to-roll type film forming apparatus. As a result, the characteristics of the solar cell can be improved, and even the transparent electrode can be formed consistently. Furthermore, both types can be used together. That is, the present invention enables mass production of high-performance solar cells with a high yield.

[Brief description of drawings]

FIG. 1 is a sectional view of a film forming apparatus according to a first embodiment of the present invention.

2 (a) to (g) are explanatory views of a transport operation of the film forming apparatus of FIG.

FIG. 3 is a sectional view of a film forming apparatus according to a second embodiment of the present invention.

4 (a) to (c) are explanatory views of the operation of the valve mechanism with a roll.

FIG. 5 is a sectional view of a film forming apparatus according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a film forming apparatus according to a fourth embodiment of the present invention.

7A and 7B are views showing an example of another intermediate storage mechanism.

FIG. 8 is a diagram showing an example of yet another intermediate storage mechanism.

FIG. 9 is a diagram showing an example of yet another intermediate storage mechanism.

FIG. 10 is a sectional view of a conventional roll-to-roll film forming apparatus.

FIG. 11 is a sectional view of a conventional stepping roll film forming apparatus.

FIG. 12: Structural diagram of single pin junction type a-Si solar cell

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flexible substrate 2 Delivery roll 3 Winding roll 4 Conveying roll 5, 5a, 5b Movable roll 6 Heater 7 Vacuum pump 8 Reaction chamber wall 9 Common chamber 10 Intermediate chamber 11 First reaction chamber 12 Second reaction chamber 13 Third Reaction chamber 14 Fourth reaction chamber 15 Plasma 16, 16a, 16b Driving roll 18 Target 19 Anode 20, 20a, 20b Partition valve 21 Metal film 22 n layer 23 i layer 24 p layer 25 Transparent electrode 26 Sending chamber 27 Winding chamber 28 Nozzle 29 Stopper 30 Electrostatic attraction plate 31 First block 32 Second block 33 Third block 38 Block wall 51 RF electrode 52 Ground electrode 54 Movable roll mechanism 55 Valve mechanism with roll 56 Drive roll mechanism

Claims (30)

[Claims] 1. A stepping roll type manufacturing apparatus for a thin film photovoltaic element, in which a plurality of thin films having different properties are stacked stepwise on a strip-shaped flexible substrate while the substrate is stationary to form a photoelectric conversion layer. In the above, the intermediate storage mechanism is provided between the reaction chambers and capable of storing a substrate having a length that is an integral multiple of the unit length (referred to as one frame length) of the substrate used for one film formation. Manufacturing equipment for thin film photoelectric conversion elements. 2. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 1, wherein the substrate has an intermediate accumulating mechanism for accumulating the substrate by deforming the substrate in a direction substantially perpendicular to the feeding direction of the substrate. 3. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 2, wherein the substrate is deformed by a solid pressing object. 4. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 3, further comprising a movable roll mechanism having a roll at the tip of the pressed object. 5. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 2, wherein the substrate is deformed by a gas pressing member. 6. The thin-film photoelectric conversion element manufacturing apparatus according to claim 2, further comprising a drive roll mechanism for accumulating the substrate by a difference in rotation amount between the two drive rolls. 7. A substrate is held from the back surface by holding an electrostatic attraction portion,
The apparatus for manufacturing a thin film photoelectric conversion element according to claim 2, wherein the substrate is deformed. 8. A partition valve is disposed on each side of the intermediate storage mechanism to provide an intermediate chamber.
An apparatus for manufacturing a thin film photoelectric conversion element according to any one of 1. 9. The method of manufacturing a thin film photoelectric conversion element using the manufacturing apparatus according to claim 1, wherein the opening times of the plurality of reaction chambers are shifted. 10. The method for manufacturing a thin film photoelectric conversion element using a manufacturing apparatus according to claim 8, wherein the opening times of the plurality of reaction chambers are shifted and the opening times of the partition valves on both sides of the intermediate chamber are shifted. . 11. A roll-to-roll manufacturing apparatus for a thin film photoelectric conversion element, wherein a plurality of thin films having different properties are continuously laminated on a strip-shaped flexible substrate while the substrate is being conveyed to form a photoelectric conversion layer. And a movable roll mechanism characterized by having a partition valve and an intermediate accumulating mechanism capable of accumulating substrates arranged before and after the dividing valve. 12. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 11, wherein the substrate has an intermediate accumulating mechanism that deforms in a direction substantially perpendicular to the substrate feeding direction to accumulate the substrate. 13. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 12, wherein the substrate is deformed by a solid pressing object. 14. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 13, further comprising a movable roll mechanism having a roll at the tip of the pressed object. 15. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 12, wherein the substrate is deformed by a gas pressing member. 16. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 12, further comprising a drive roll mechanism for accumulating a substrate by a difference in rotation amount between two drive rolls. 17. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 12, wherein the substrate is deformed by holding the substrate from the back surface by holding the electrostatic attraction portion. 18. A roll-equipped valve mechanism having an intermediate chamber partitioned by two partition valves and comprising at least three movable roll mechanisms arranged in front of and behind the two partition valves. The manufacturing apparatus of the thin film photoelectric conversion element as described in any one of 11 to 17. 19. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 18, further comprising an exhaust device for evacuating an intermediate chamber partitioned by two partition valves. 20. A roll-to-roll method for manufacturing a thin film photovoltaic element using the manufacturing apparatus according to claim 11, wherein a part of the substrate is stationary during film formation. And a method for manufacturing a thin film photoelectric conversion element. 21. A roll-to-roll method for manufacturing a thin film photovoltaic element using the manufacturing apparatus according to claim 18 or 19, wherein there is a time during which part of the substrate remains stationary during film formation. A method for manufacturing a thin film photoelectric conversion element, characterized in that the opening times of two partition valves are shifted. 22. In a thin-film photovoltaic device manufacturing apparatus in which a plurality of thin films having different properties are laminated on a strip-shaped flexible substrate to form a photoelectric conversion layer, a roll-to-roll system of continuous film formation is used. It is equipped with a reaction chamber and a stepping roll type reaction chamber for forming a film stepwise while the substrate is stationary.
Between these reaction chambers, there is an intermediate storage mechanism capable of storing a substrate having a length that is an integral multiple of the unit length (referred to as one frame length) of the substrate used in one step film formation of the stepping roll method. An apparatus for manufacturing a thin film photoelectric conversion element, characterized in that 23. An apparatus for manufacturing a thin film photoelectric conversion element according to claim 22, wherein the substrate has an intermediate accumulating mechanism for deforming the substrate in a direction substantially perpendicular to the feeding direction of the substrate to accumulate the substrate. 24. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 23, wherein the substrate is deformed by a solid pressing object. 25. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 24, further comprising a movable roll mechanism having a roll at the tip of the pressed object. 26. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 23, wherein the substrate is deformed by a gas pressing member. 27. An apparatus for manufacturing a thin film photoelectric conversion element according to claim 23, further comprising a drive roll mechanism for accumulating the substrate by a difference in rotation amount between the two drive rolls. 28. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 23, which has an electrostatic attraction portion and holds the substrate from the back side to deform the substrate. 29. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 22, further comprising a partition valve between the stepping roll type reaction chamber and the movable roll mechanism. 30. A method of manufacturing a thin film photoelectric conversion element using the manufacturing apparatus according to claim 22, wherein a part of the film is continuously formed by transporting the substrate by a roll-to-roll method. Then, the other film is formed stepwise by the stepping roll method while the substrate is stationary, and the method for manufacturing a thin film photoelectric conversion element.