JPH0658885B2 - Amorphous silicon film manufacturing equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to an amorphous silicon film (hereinafter referred to as an amorphous silicon film) formed by a can-type plasma CVD method while transferring a flexible substrate by a roll-to-roll method in which a flexible substrate is unwound from a roll and wound into a low. The present invention relates to an a-Si film manufacturing apparatus for continuously forming an "a-Si film"), which is suitable for manufacturing amorphous solar cells and the like.

[Prior Art] A plurality of different conductivity type a-Si films used in a photovoltaic device such as a solar cell and a photodetector are formed into a flexible sheet (for example,
As an apparatus for continuously forming on a polymer film, a metal thin film, a ceramic thin film, etc., JP-A-58-216475 and JP-A-59-34668 disclose flexible films such as a polymer film. A roll-to-roll method in which the substrate is unwound from the roll and wound on the roll, and a-Si film is continuously formed while being transferred on the parallel plate electrode in the film formation area or on the can electrode with the can as one electrode. An apparatus for producing an a-Si film is disclosed. Especially in the latter can method, since the substrate is closely attached to the can and transferred by its rotation, scratches are generated due to the slip of the substrate and the scratches are transferred to the a-Si film surface after the roll is formed. It is desired to put it into practical use in that a good quality a-Si film can be obtained without problems such as damage to the film.

By the way, plasma CVD using a polymer film substrate
In the production of an a-Si film by the method described above, it is desirable that the temperature of the polymer film substrate be as high as possible during formation of the a-Si film for reasons of increasing the deposition rate and improving the film quality.

On the other hand, in order to prevent wrinkles and meandering during stable film transportation, it is necessary to apply a tension above a certain limit to the polymer film substrate.

However, these two requirements are conflicting,
Since the elastic modulus of the polymer film decreases extremely with increasing temperature, if a large tension is applied when depositing the a-Si film in order to ensure stable running, the polymer film will experience a tensile stress above the allowable limit. However, there is a problem that the polymer film is effectively deformed and vertical wrinkles are generated, and stable long-term continuous film formation is difficult.

[Object of the Invention] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an apparatus for manufacturing an a-Si film by a can-type plasma CVD method that enables stable continuous film formation for a long period of time.

[Structure and Action of the Invention] The above-mentioned object is achieved by the present invention described below. That is, the present invention uses a plasma CVD method including a can that is one of the electrodes and an arc-shaped electrode that faces the can.
-Has a plurality of sets of film forming regions of the Si film, forms a film while unwinding the flexible substrate from the roll and supporting it on the can for transfer.
In the apparatus for manufacturing an a-Si film wound on a roll, a tension control means for independently controlling the tension of the substrate between the roll and the can and between the cans is provided. -Si film manufacturing equipment.

As described above, in the present invention, the tensions of the substrates between all the cans and between the cans and the rolls are controlled independently of each other, so that the tension can be set appropriately for each part of the substrate.
Therefore, stable film formation can be realized over a long period of time as a whole.

From the above-mentioned point, the present invention can be applied particularly advantageously to a polymer film in which a flexible substrate has poor heat resistance, but it is clear from the gist of the present invention that it can be applied to all flexible substrates that can be roll-formed, such as metal and ceramics. Is. Also, when a polyethylene terephthalate film is used, which is particularly inferior in heat resistance to a polymer film but has excellent mechanical properties such as dimensional stability and surface properties, the effect is remarkable, including improvement in quality of a-Si film. is there.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a front view showing an internal structure of an a-Si film manufacturing apparatus for manufacturing a solar cell in one embodiment of the present invention.

In the figure, 1 is an unwinding roll, 2 is a substrate made of a polymer film fed from the unwinding roll, 3a, 3b, 4
a, 4b, 5a, and 5b are p-, i-, and n-conduction type a-S, respectively.
A can forming an electrode pair for plasma CVD forming an i film and an arc-shaped electrode facing the can. 6 is an unwinding roll for winding the polymer film 2 having a plurality of a-Si films formed thereon. Chamber 11, first reaction chamber 12, second reaction chamber 13, third
The reaction chamber 14 and the winding chamber 15 are provided with buffer chambers 16a, 16b, 16c,
The basic configuration that enables continuous three-layer film formation by connecting with 16d is
This is the same as that disclosed in the above-mentioned JP-A-58-216475 and JP-A-59-34668, and the illustration and description of the other exhaust system, gas supply system, etc. are omitted.

Reference numerals 7a, 7b, 7c and 7d in the figure are tension detectors for detecting the tension of the substrate 2, using commercially available tension detectors, between the unwinding roll 1 and the can 3a, between the can 3a and the can 4a, It is provided between the cans 4a and 5a, between the cans 5a and the winding roll 6, that is, between all the cans and rolls, and between the cans. In the figure, 8a, 8b, 8c, and 8d are control devices for the tension control means, which are commercially available control devices and are used for tension detectors 7a, 7b, 7c,
Based on the detection signals from 7d, the unwinding roll 1, the cans 3a, 4a, and the winding roll 6 corresponding to each are adjusted,
The tension of the substrate 2 is controlled to the respective set values of the control devices 8a, 8b, 8c, 8d.

8e in the figure is a speed control device for controlling the rotation speed of the can 5a to be constant, and a commercially available control device is used.

Reference numerals 9a, 9b, 9c, and 9d in the drawing are guide rolls, which are known dancer rolls so as to be able to absorb a sudden change in tension, but they may be simple guide rolls.

In the a-Si film manufacturing apparatus described above, the rotation of the can 5a serving as a pacemaker is made constant by the speed control device 8e so that the speed of the polymer film 2 becomes constant, and the tension control devices 8c and 8d respectively make To maintain the set tension,
By adjusting the rotational speeds of the drive systems of 4a and 6, and also the tension control devices of 8a and 8b, by adjusting the rotational speeds of 1 and 3a respectively, 3a, 3b, 4a, 4b, 5a, When the polymer film 2 continuously passes between the electrode pairs of 5b, there is no wrinkle or meandering, and the polymer film 2 adheres to the heating cans 3a, 4a, 5a, so that stable and high performance p, i , N a-Si films are laminated on the polymer film 2.

Since a plasma CVD film typified by an a-Si film has a low film processing speed, even if a tension control means is provided as described above, the time constant is slow, and rapid tension fluctuation cannot sufficiently control tension. There are cases.

In such a case, it is also possible to absorb the sudden minute tension fluctuations applied by the dancer rolls 9a, 9b, 9c, 9d and deal with such minute tension fluctuations.

In addition, in this example, a continuous film formation of three layers of p, i, and n for manufacturing a solar cell is shown, but the layer structure is arbitrary and the same a-
It goes without saying that it can be applied to the case where the Si film is divided into a plurality of layers to be manufactured.

[Advantages of the Invention] As described above, in the present invention, in the multilayer film forming CVD apparatus provided with the roll can, the tension detector for detecting the tension of the film is provided between the cans so that the tension between the cans is constant. By making it adjustable so that wrinkles and meandering do not occur in the polymer film, and the lower limit tension required for the polymer film to be uniformly heated by the heating can is exceeded,
Moreover, in the proper tension range in which the polymer film during film formation or transportation does not cause plastic deformation due to tension and does not exceed the upper limit tension,
Since the tension of the polymer film before and after each film forming constitution is controlled, the performance of the formed amorphous silicon multilayer film is remarkably improved.

Furthermore, since the tension of each part is controlled, when changing the transport film speed, other can rotation speeds follow only by changing the can rotation speed that serves as a pacemaker.
In addition, when changing the tension at one location, the effect of the tension and rotation speed fluctuation on each part due to changing the tension at one location can be automatically corrected simply by resetting the tension at the desired location. It greatly contributes to process stabilization.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an internal configuration of an a-Si film manufacturing apparatus according to an embodiment of the present invention. 1: unwind roll, 2: substrate 3a, 4a, 5a: can, 6: take-up roll 7a, 7b, 7c, 7d: tension detector 8a, 8b, 8c, 8d: tension control device

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-60-72278 (JP, A) JP-A-57-162423 (JP, A) JP-A-61-163272 (JP, A)

Claims (5)

[Claims] 1. A flexible substrate is unrolled from a roll having a plurality of film forming regions of an amorphous silicon film formed by a plasma CVD method because it becomes a can that serves as one electrode and an arc-shaped electrode facing the can. In an apparatus for producing an amorphous silicon film, which is supported on the can and formed while being transferred, and wound on a roll, tensions of the substrate between the roll and the can and between the cans are independently controlled. An apparatus for producing an amorphous silicon film, which is provided with a tension control means. 2. The apparatus for producing an amorphous silicon film according to claim 1, wherein each of the film forming regions is a film forming region of a different type of amorphous silicon film. 3. The tension control means detects a tension of a substrate provided between the can and the roll and between the cans, and a tension detector for receiving a signal from the tension detector. The apparatus for producing an amorphous silicon film according to claim 1 or 2, further comprising: a control device that controls the tension to a set value by changing the rotation speed of a front or rear can or a roll. 4. The apparatus for producing an amorphous silicon film according to claim 3, wherein one of the can and the roll is controlled at a constant speed, and the rest is controlled at a constant tension by the tension control means. 5. The apparatus for producing an amorphous silicon film according to claim 1, 2, 3, or 4, wherein the substrate is a polymer film.