JPH07221025A - Manufacture of thin film photoelectric conversion element - Google Patents

Abstract

PURPOSE:To make it possible to form a film of good quality on a flexible board having a through hole, by making both spaces into a vacuum state through an air path provided between both spaces surrounded with the flexible board and each member in a film formation chamber, and preventing raw gas remaining in the spaces. CONSTITUTION:Inside walls 61 and 71 joined with each outer wall 6 or 7 of upper and lower film formation chambers are provided opposite to each other. The inside walls 61 and 71 have round discharging openings 13 and 14 as a bypass between both film formation spaces. During the film formation, the flexible board is put between the end of the wall 6 of the upper film formation chamber and the end of the wall 7 of the lower film formation chamber. The flexible board on one side of the film formation chamber is put between edge parts of the faces of the inside walls 61 and 71 and sealed hermetically from an inside space 10 of the lower film formation chamber with a sealing material 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin film photoelectric conversion device manufacturing apparatus for forming a photoelectric conversion layer such as amorphous silicon (hereinafter abbreviated as a-Si) on a flexible substrate by a stepping roll method. ..

[0002]

2. Description of the Related Art Each layer including a photoelectric conversion layer containing a-Si as a main material is formed on a flexible substrate made of a long polymer material or a metal such as stainless steel to manufacture a thin film photoelectric conversion element. The method is superior in terms of productivity. As a method of forming a plurality of layers on a long flexible substrate, a roll-to-roll method of forming a film on a substrate moving in each film formation chamber and a film formation on a substrate stopped in the film formation chamber After that, there is a stepping roll method in which the substrate portion after the film formation is sent out of the film formation chamber. In the stepping roll method of forming a film by using the plasma CVD method, the film forming chamber is opened, the substrate is moved by one frame, the film forming chamber is sealed, the source gas is introduced, the pressure is controlled, the discharge is started, the discharge is finished, the source gas is stopped, and the gas is drawn. The operation of opening the film forming chamber is repeated. The film forming apparatus adopting the step roll method is superior to the ordinary roll-to-roll film forming in the following points.

(1) There is no interdiffusion of gas between adjacent film forming chambers. (2) The device is compact. FIG. 2 shows an example of a stepping roll type film forming apparatus, which has a structure in which a plurality of film forming chambers 21 to 24 are arranged in a common chamber 20, and each film forming chamber has an electrode containing a heater 2. It can be opened and sealed by raising and lowering 3. A flexible substrate 1 made of a polymer thin film or a metal thin film such as stainless steel is passed between a high voltage electrode 4 connected to a ground electrode 3 containing a heater 2 in each deposition chamber and a roll 25. The transfer between No. 26 and No. 26 is performed when the film formation chamber is opened, and the film formation is performed when the film formation chamber is closed.

3 (a) and 3 (b) show cross sections of the stepping roll type film forming chamber when it is opened and when it is sealed.
A box-shaped wall 6 of the upper film forming chamber and a wall 7 of the lower film forming chamber face each other on the opening side above and below the flexible substrate 1 which is intermittently conveyed. A high voltage electrode 4 is provided in the lower film forming chamber, and a ground electrode 3 is provided in the upper film forming chamber. During film formation,
As shown in (b), the wall 6 of the upper film forming chamber is lowered, and the ground electrode 3 holds the substrate 1 in contact with the sealing material 8 attached to the opening side end surface of the wall 7 of the lower film forming chamber. Thus, the wall 7 of the lower film forming chamber and the substrate 1 form an airtightly closed film forming space 10 communicating with the exhaust pipe 9, and by applying a high frequency voltage to the high voltage electrode 4, plasma is formed in the film forming space 10. And the raw material gas introduced from an introduction pipe (not shown) is decomposed to form a film on the substrate 1. In this case, the sealing material 8
Comes into contact with the surface end portion of the wall 6 of the upper film forming chamber heated by the heater 2 through a flexible substrate having a thickness of several tens to several hundreds of microns, and the temperature of the contact portion of the sealing material 8 is The temperature is almost equal to that of the wall 6 of the upper film forming chamber. The heater temperature during film formation is 2
00 to 300 ° C. On the other hand, when using fluorine rubber or the like as the sealing material 8, the sealing part should be 150 ° C to prevent degassing.
Must be kept below. Therefore, it is important to keep the surface temperature of the wall 6 of the upper film forming chamber at 150 ° C. or lower, and a distance of at least 2 mm, preferably 5 mm or more, between the ground electrode 3 and the wall 6 of the upper film forming chamber. It is necessary to provide.

[0005]

At the time of film formation shown in FIG. 3B, an internal space 11 surrounded by the upper film forming chamber wall 6 and the substrate 1 is formed. However, as described in Japanese Patent Application No. 347394 and other specifications related to the applicant's application, the transparent electrode layer of the thin film photoelectric conversion element formed on one surface of the substrate and the other surface are formed on the transparent electrode layer. A structure has been developed in which the formed metal electrode layer is connected via a conductor passing through a through hole formed in the substrate to shorten the current flow distance in the transparent electrode layer having a high sheet resistance. In addition, a marker hole for alignment may be formed on the substrate. When the thin film of such a photoelectric conversion element is formed by the apparatus shown in FIG. 3, the substrate 1 is formed through the through holes which are already dispersed and formed in the substrate 1.
The spaces 10 and 11 on both sides of are communicated with each other. This causes the following problems. (1) The source gas invades and collects in the internal space 11 of the upper film forming chamber through the through hole. This accumulated gas or space 1
When 1 is not hermetically sealed, the gas mixed with the atmosphere is inversely diffused into the film formation space 10 and adversely affects the film formation. (2) When forming two or more kinds of films in one film forming chamber,
After forming the first layer, the second layer is formed before the gas accumulated in the space 11 is completely drawn. Therefore, when the first layer is a p-type or n-type doped film, the impurities are mixed into the second layer, and the film having different characteristics such as conductivity and optical gap from the film to be originally obtained. Will be created.

An object of the present invention is to solve the above problems and provide an apparatus for manufacturing a thin film photoelectric conversion element capable of forming a high quality film with good controllability on a flexible substrate having a through hole. It is in.

[0007]

In order to achieve the above-mentioned object, the present invention provides a flexible substrate to be transferred on the opening side of two portions each having a box-shaped wall of a film forming chamber. The substrate is sandwiched between the opening side end faces of the wall bodies of both parts of the film forming chamber, and the film forming space surrounded by one part of the film forming chamber and the substrate is evacuated from the exhaust port communicating with the space. West,
In the thin film photoelectric conversion element manufacturing apparatus for applying a voltage between the electrode in the space and the other part of the film forming chamber and the electrode in the space surrounded by the substrate, each part of the film forming chamber And a ventilation path communicating with both spaces surrounded by the substrate. The ventilation path is a flexible pipe, or it is opened facing the portion provided on the opening side of the wall of both portions of the film forming chamber where the flexible substrate does not pass, and is formed during film formation. It is effective to have an opening that is airtightly isolated and communicates with the outside of the membrane chamber.

[0008]

By connecting the space formed by the film forming chamber and the substrate during the film formation through the ventilation passage, both spaces are evacuated and the source gas is not accumulated.

[0009]

EXAMPLE FIGS. 1 (a) and 1 (b) are cross-sectional views of a film forming chamber according to an embodiment of the present invention when the film forming chamber is opened and closed, and FIGS.
The same parts as those in FIG. Figure 1
At the time of sealing the film forming chamber shown in (b), the space 10 on the high voltage electrode 4 side and the space 11 on the ground electrode side with the flexible substrate 1 sandwiched therebetween are connected by a flexible pipe 12. It is desirable that the material of the piping is one that is less outgassed and has excellent heat resistance, and a stainless steel tube, polytetrafluoroethylene tube, or the like is suitable. The length of the pipe needs to be designed in consideration of the lifting stroke of the wall 6 of the upper film forming chamber so as not to hinder the opening and closing of the film forming chamber.

Using this device, the flexible substrate 1
Using a child film, film / metal electrode / (n-i-
p)-(nip) / two-layer tandem separator with transparent electrode structure
The case of forming a stepping roll film is described below.
It The photoelectric conversion layer of the tandem cell is, as shown in FIG.
p layer 31, p / i interface layer (buffer layer) 32, i layer 3
3, n layer 34, p layer 35, p / i interface layer 36, i layer 3
7 and n layers 38, each layer is made of p and p / i
The surface layer is a-SiO, the i layer is a-Si, and the n layer is μc (fine
Crystal) -Si. These films use SiH as the main gas._Four, Rare
Release gas H₂And when forming a-SiO, CO₂The oxygen source
And B is used for forming the p-layer and the n-layer, respectively.₂H ₆and
PH₃Is used as a doping gas. Also typical
The thickness of each layer is p layers 31, 35, p / i interface layer 32,
36, n layers 34 and 38 are the top cell and the bottom cell.
Are 10 nm, 10 nm, and 20 nm, respectively.
The film thickness of the i-layers 33 and 37 of the
They are 80 nm and 400 nm, respectively. Solar cell with this structure
As shown in FIG.
For example, in order to form a film with a roll type apparatus, for example, the first film forming chamber 21
At the n layer 38, the second film forming chamber 22 at the i layer 37, the third film forming chamber 2
3 in the p / i interface layer 36, the p layer 35, and in the fourth film formation chamber 24
Layer 34, i layer 33, p / i interface layer 32, and p layer 31 are formed
It is possible to do it. In the case of this example, the fourth film forming chamber 24
Therefore, mixing of the residual gas into the i-layer after forming the n-layer causes the problem 2 described above.
Become. Flexible pipe 12 used as a bypass line
This problem can be cleared if the inner diameter of
It has been confirmed that it is possible. However, when forming a film
The problem 1 mentioned above is to introduce and exhaust the source gas without stagnation.
It is necessary to solve the problem, and for this purpose, the pipe inner diameter is 20 nm.
It is desirable to make it φ or more.

5 (a) and 5 (b) are cross-sectional views of the film forming chamber of another embodiment of the present invention when the film forming chamber is opened and sealed, and FIG. 6 is a plan view of the seal part of the film forming chamber. In this case, the inner walls 61 and 7 connected to the outer walls 6 and 7 of the upper film forming chamber and the lower film forming chamber, respectively.
1 are provided so as to face each other, and circular vent holes 13 and 14 are opened as a bypass of both film forming spaces as shown in FIG. The flexible substrate 1 is formed as shown in FIG.
As shown in (b), it is sandwiched between the end of the wall 6 of the upper film forming chamber and the end of the wall 7 of the lower film forming chamber, and at one side of the film forming chamber, the edge of the surface of the inner walls 61, 71. It is sandwiched and is kept airtight by the sealing material 8 with the internal space 10 of the lower film forming chamber.
On the other hand, a ring-shaped sealing material 81 is provided around the vent holes 13 and 14.
Is attached to maintain the airtightness with respect to the space outside the film formation chamber inside the vent holes 13 and 14. In the case of the embodiment shown in FIG. 1, a space for installing the flexible pipe 12 is required, but in the case of the present embodiment, this space is unnecessary, and it is considered to be advantageous for downsizing. In addition, as in the embodiment shown in FIG.
Although the above-mentioned problem 2 can be solved by the above, it is desirable to set it to 20 nmφ or more in order to clear the problem 1.

[0012]

According to the present invention, when a film is formed by the stepping roll method, by providing a ventilation path connecting both spaces formed on both sides of the flexible substrate, the gas in the space where the exhaust port is not provided is provided. It is possible to prevent the accumulation of. This makes it possible to realize a clean film formation in which fresh source gas is constantly supplied. Further, even if a plurality of types of semiconductor layers are formed in the same film forming chamber, it is possible to realize film formation without the influence of residual gas. Therefore, the present invention enables high-throughput and clean film formation by making use of the original characteristics of the stepping roll type apparatus, and enables mass production of low-cost and high-performance thin film photoelectric conversion elements.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an apparatus for manufacturing a thin film photoelectric conversion element according to an embodiment of the present invention, in which (a) is a film forming chamber opened and (b) is a film forming chamber sealed.

FIG. 2 is a sectional view of a stepping roll film forming apparatus.

FIG. 3 shows a conventional thin-film photoelectric conversion element manufacturing apparatus,
(a) is a cross-sectional view when the film forming chamber is opened, and (b) is a sectional view when the film forming chamber is sealed.

FIG. 4 is a cross-sectional view showing the structure of a photoelectric conversion layer of a thin film photoelectric conversion element manufactured by the device of the present invention.

FIG. 5 shows a thin-film photoelectric conversion element manufacturing apparatus according to another embodiment of the present invention, in which (a) is a cross-sectional view when the film formation chamber is open and (b) is a film formation chamber closed.

6 is a plan view of a lower film forming chamber of the apparatus shown in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Flexible substrate 2 Heater 3 Grounding electrode 4 High voltage electrode 6 Upper film forming chamber wall 7 Lower film forming chamber wall 8, 81 Sealing material 9 Exhaust port 10 Lower film forming chamber inner space 12 Flexible piping 13, 14 Ventilation Mouth 61, 71 Inner wall

Claims (3)

[Claims] 1. A flexible substrate being conveyed is stopped between the opening sides of two portions of the film forming chamber, each of which has a box-shaped wall, and the substrate is placed between the walls of both portions of the film forming chamber. A film forming space surrounded by one part of the film forming chamber and the substrate sandwiched between the end faces on the opening side is evacuated from an exhaust port communicating with the space, and the electrode in the space and the other part of the film forming chamber and the substrate are evacuated. In a case where a film is formed by applying a voltage to an electrode in a space surrounded by, a vent passage communicating with both parts surrounded by the film forming chamber and the substrate is provided. Device for manufacturing thin film photoelectric conversion element. 2. The apparatus for manufacturing a thin film photoelectric conversion element according to claim 1, wherein the ventilation passage is a flexible pipe. 3. A ventilation passage is opened facing the portion provided on the opening side of the wall of both portions of the film forming chamber where the flexible substrate does not pass, and is airtight from the outside of the film forming chamber during film formation. The thin film photoelectric conversion element manufacturing apparatus according to claim 1, wherein the manufacturing apparatus comprises an opening part which is isolated from and communicates with.