JPH10158848A - Formation of semiconductor thin film and aperture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for formation of semiconductor thin films for formation of a large quantity of photoelectromotive elements which have high photoelectric conversion efficiency, having high quality and excellent uniformity, having higher reproducibility and have decreased defects over a large area on a continuously moving beltlike member and an apparatus therefor. SOLUTION: This method for formation of the semiconductor thin films consists in passing the belt-like member through plural film forming chambers connected by gas gates 306 having gas introducing ports 310 for introducing scavenging gases to slit-like separating passages while continuously moving the belt-like member in a longitudinal direction, successively laminating the semiconductor thin films on the belt-like member 307 in the respective film forming chambers and continuously taking up the belt-like member laminated with the semiconductor thin film in a taking-up stage. In such a case, at the time of taking-up the belt-like member in the taking-up stage, the taking-up is executed by controlling the temp. of the belt-like member; for example, a steering roller for guiding the belt-like member to the belt-like member taking-up means is made controllable in its temp.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for forming a semiconductor thin film, and more particularly to a method and an apparatus for continuously producing a photovoltaic element such as a solar cell. For example, the present invention relates to a method and an apparatus for mass-producing a photovoltaic element such as a solar cell using amorphous silicon or an amorphous silicon alloy.

[0002]

2. Description of the Related Art In recent years, the problem of environmental pollution has become serious.
It does not cause problems such as radioactive contamination due to nuclear power generation and global warming due to thermal power generation.In addition, since sunlight falls all over the earth, there is little uneven distribution of energy sources, and moreover, complex Attention has been paid to clean power generation methods that can respond to future increases in power demand without causing earth destruction, such as relatively high power generation efficiency without the need for large-scale facilities. Various research and developments have been made.

By the way, in order to establish a power generation system using a solar cell to meet the power demand, the solar cell used has a sufficiently high photoelectric conversion efficiency.
It is basically required that they have excellent characteristic stability and that they can be mass-produced. As a method for continuously forming a semiconductor functional deposition film used for a photovoltaic element or the like on a substrate, independent film forming chambers for forming various semiconductor layers are provided, and each of these film forming chambers includes a gate valve. A method of forming various semiconductor layers by sequentially moving a substrate to each film forming chamber and connecting them by a load lock method via an intervening load lock method is known.

[0004] As a method for remarkably improving mass productivity,
U.S. Pat. No. 4,400,409 discloses rolls.
A continuous plasma CVD method employing a roll-to-roll method is disclosed. According to this method, a long strip-shaped member is used as a substrate, and while a conductive semiconductor layer required in a plurality of glow discharge regions is deposited and formed, the substrate is continuously transported in its longitudinal direction. It is stated that an element having a semiconductor junction can be continuously formed.

[0005]

However, it takes several hours to form a semiconductor layer on a belt-shaped substrate having a length of several hundred meters, and maintains a uniform discharge state with good reproducibility. It is necessary to form a semiconductor layer. There is a need for a method for continuously forming a high-quality and uniform semiconductor deposition film continuously and with high yield over the entire length of the long strip from the beginning to the end. In particular, when the temperature is high, it has been difficult to uniformly wind the band-shaped member around the bobbin due to the kinetic friction between the band-shaped member and various rollers. Among the kinetic frictions, slippage friction, rolling friction and the like are not constant, so that a winding deviation occurs, and a bobbin wound in a roll shape sometimes becomes a so-called bamboo shoot shape due to the winding deviation. If the belt-like member is advanced to the next step in this state, plasma leakage will occur due to contact between the belt-like member and the apparatus or discharge instability during film formation, causing variations in characteristics, resulting in a defective product. Problems such as lowering the yield.

Further, in the winding step of the band-shaped member of the semiconductor forming apparatus, the temperature at the time of winding the band-shaped member around the bobbin after the deposition of the semiconductor layer is high, and the band-shaped member is not sufficiently cooled. As described above, when the temperature of the band-shaped member is high, the substrate is stretched and contracts when cooled, so that the winding of the band-shaped substrate wound on the bobbin increases with time, and the deposited film has a stress. , And the yield and the characteristics have been lowered. When the band-shaped member is unwound or stress is applied to the semiconductor thin film, a functional element such as a photovoltaic element can be spread over a large area.
It has been difficult to achieve good uniformity, good reproducibility, good yield, and high productivity.

Therefore, the present invention solves the above-mentioned problems in the conventional art, and provides a method for forming a continuously moving belt-like member on a belt-like member.
Provided is a method and apparatus for forming a semiconductor thin film for producing a large number of photovoltaic elements having high photoelectric conversion efficiency, high quality, excellent uniformity, higher reproducibility, and less defects over a large area. It is intended to be.

[0008]

According to the method of forming a semiconductor thin film of the present invention, a scavenging gas is introduced into a slit-like separation passage while continuously moving a belt-like member in a longitudinal direction to solve the above-mentioned problems. In a plurality of film forming chambers connected by a gas gate having a gas inlet, the semiconductor thin films are sequentially stacked on the band-shaped member in each of the film forming chambers, and the band-shaped member in which the semiconductor thin films are stacked is taken up in a winding step. A method for forming a semiconductor thin film to be continuously wound, wherein the winding of the band-shaped member is controlled by controlling the temperature when winding the band-shaped member in the winding step. Further, the temperature control in the method for forming a semiconductor thin film of the present invention includes a steering roller for guiding the belt-like member to the belt-like member winding means,
It is characterized in that the temperature control is performed.

In the apparatus for forming a semiconductor thin film of the present invention, a plurality of components connected by a gas gate having a gas inlet for introducing a scavenging gas into a slit-shaped separation passage while continuously moving the belt-shaped member in the longitudinal direction. Passing through a film chamber, sequentially laminating a semiconductor thin film on the strip-shaped member in each of the film forming chambers,
An apparatus for forming a semiconductor thin film that continuously winds a band-shaped member on which the semiconductor thin film is laminated by a band-shaped member winding unit in a winding step, wherein a temperature control unit is provided immediately before the band-shaped member winding unit, It is characterized in that the belt-shaped member is controlled in temperature by control means and wound up. Further, the temperature control means in the semiconductor thin film forming apparatus of the present invention,
It is characterized by comprising a temperature control mechanism provided on the steering roller.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS By using the method and the apparatus of the present invention, a high-quality and uniform semiconductor deposition film can be continuously formed over the entire hundreds of meters of a long strip from the beginning to the end. It can be formed while maintaining an extremely high yield, and after forming a conventional semiconductor thin film, it can be wound around a bobbin at a high temperature, causing winding deviation,
Problems such as stress applied to the thin film can be eliminated. When producing a functional element such as a photovoltaic element, a multilayer thin film such as a base reflective layer, a semiconductor layer, and an anti-reflection layer is formed. When the belt-like member comes into contact with the wall surface while passing through the slit or the chamber, or the degree of winding deviation is severe, and if the clearance exceeds the clearance in such a case, the belt-like member may be caught. As a result, production planning of products is delayed, which affects overall production.

[0011] Further, when the position of the discharge region and the position of the belt-shaped member are displaced, discharge leakage or discharge instability occurs, which leads to variation in characteristics and reduction in yield. The above problem can be solved by cooling the belt-like member with a steering roller before winding the belt-like member around a bobbin, as in the present invention. In other words, when the hot strip passes through the steering roller,
It cools and cools down to a little higher than room temperature,
Sliding between the belt-shaped member and the steering roller is reduced, the deviation is small, and the film is smoothly wound within an allowable range. As a result, the functional element such as a photovoltaic element formed by multi-step semiconductor thin film deposition can be realized over a large area with good uniformity, good reproducibility, good yield, and high productivity. Things become possible.

As the temperature control mechanism used for the steering roller, for example, a mechanism incorporating a Peltier element, a mechanism in which a refrigerant is circulated inside the steering roller, and the like can be mentioned. In any case, a cooling mechanism for controlling the temperature of the belt-shaped member, and a structure rotatable as a roller, a structure capable of operating within an allowable range of winding deviation,
Any mechanism may be used, and specific specifications are not limited to these examples.

[0013]

EXAMPLES Hereinafter, specific examples of the apparatus and examples of the present invention will be shown, but the present invention is not limited thereto. (Example 1 of Apparatus) FIG. 1 is a conceptual schematic diagram showing an example of the internal structure of a vacuum container for winding a belt-shaped member according to the present invention. The band-shaped member 102 on which the semiconductor thin films are sequentially stacked is introduced into the vacuum container 100 through the gas gate 103, is passed through the steering roller 101, and is wound together with the interleaf 104 on the band-shaped member winding bobbin 105. FIG. 2 shows a detailed steering roller temperature control mechanism. The refrigerant is returned from the refrigerant introduction unit 202 to the steering roller 201, and the refrigerant is discharged to the refrigerant discharge unit 2
03, the inside of the steering roller 201 is temperature-controlled by a temperature control mechanism (not shown). At this time, the steering drive unit 204 rotates together with the steering roller 201, and the refrigerant introduction unit 202 and the refrigerant derivation unit 203 come into contact with the steering drive unit 204 by a vacuum seal or the like, and rotate together with the introduction and derivation fixing unit 205. It does not have a structure. By using the above mechanism, the steering roller is cooled and the temperature of the belt-shaped member is controlled.

[Embodiment 1] A continuous plasma CVD method employing a roll-to-roll method as shown in FIG. A single type photovoltaic device was manufactured.

A specific example of the production will be described below.

FIG. 3 is a simplified schematic diagram of an example of a single type photovoltaic device manufacturing apparatus using the manufacturing method of the present invention. Examples of the manufacturing apparatus include vacuum containers 301 and 305 for feeding and winding the belt-shaped member 307, a first conductive type layer forming vacuum container 302, an i-type layer forming vacuum container 303,
The second conductive type layer forming vacuum container 304 is connected to the gas gate 30.
6 are connected to each other. The method for winding the belt-like member in the vacuum vessel for winding the belt-like member was the method shown in FIG.

Using the manufacturing apparatus shown in FIG. 3, under the manufacturing conditions shown in Table 1, a first conductive type layer, an i-type layer, and a second conductive type layer are formed on the lower electrode as follows. As a result, a single type photovoltaic element was continuously manufactured. (Element-Real 1) First, a vacuum vessel 301 having a substrate sending-out mechanism is sufficiently degreased and washed, and as a lower electrode, a silver thin film of 100 nm and a ZnO thin film of 1 μm are formed by a sputtering method.
SUS430BA strip 307 (width 1)
A bobbin 317 (20 mm × 200 m × 0.13 mm in thickness) is set, and the band-shaped member 307 is passed through the gas gate 306 and each non-single-crystal-layer-forming vacuum vessel to form a band-shaped member winding mechanism. Through the vacuum container 305, and the tension was adjusted to a level where there was no slack.

Therefore, each of the vacuum vessels 301, 302, 30
3, 304 and 305 are 1 × 10 ^{−4 by} a vacuum pump (not shown).
Vacuum was drawn to Torr or less.

Next, a gate gas introducing pipe 31 is connected to the gas gate.
4, H2 was supplied as a gate gas at a flow rate of 700 sccm, and the band member 307 was heated to 350 ° C., 350 ° C., and 200 ° C. by the lamp heater 309, respectively. And
From each gas introduction pipe 310, 40 sccm of SiH4 gas and PH3 gas (2% H2) were used as the first conductivity type layer forming gas.
2 diluted product) 50 sccm, H2 gas 500 sccm,
As an i-type layer forming gas, SiH4 gas is supplied at 100 scc each.
m, H2 gas is 500 sccm each, and as a second conductivity type layer forming gas, SiH4 gas is 10 sccm, BF2 gas (2% H2 diluted product) is 100 sccm, and H2 gas is 200 sccm.
0 sccm was introduced.

Each of the vacuum vessels 301, 302, 303, 30
4 and 305, the pressure in each pressure gauge 316 is 1.0 Torr, 1.5 Torr, 1.8 Torr, respectively.
It was adjusted by a conductance valve (not shown) so that the pressure became 1.6 Torr and 1.0 Torr. Thereafter, 500 W is applied to each cathode electrode 312 to form the first conductivity type layer.
200 W for forming the i-type layer and 70 W for forming the second conductivity type layer
0 W was supplied.

Next, the belt-shaped member 307 was transported in the direction of the arrow in the figure, and a first conductive type layer, an i-type layer, and a second conductive type layer were sequentially laminated on the band-shaped member. Next, on the second conductivity type layer, ITO (In2O3 + SnO2) was vapor-deposited to a thickness of 80 nm as a transparent electrode by vacuum vapor deposition.
Al was vapor-deposited at 2 μm by vacuum vapor deposition to prepare a photovoltaic element. (Element-Actual 1) Table 1 shows the conditions for forming the photovoltaic element described above. Also,
FIG. 4 shows a conceptual diagram of the element.

[0022]

[Table 1] (Comparative Example 1) A single photovoltaic device was manufactured in the same procedure as in Example 1 except that the method of winding the belt member and the method of changing the steering roller in the vacuum chamber for winding the belt member were changed to the method shown in FIG. An element was manufactured. (Element-Ratio 1) Example 1 (Element-Real 1) and Comparative Example 1 (Element-Ratio 1)
The uniformity of the characteristics and the yield of the photovoltaic element prepared in the above were evaluated. The characteristic uniformity was determined in Example 1 (element-actual 1),
The photovoltaic element on the belt-shaped member prepared in Comparative Example 1 (element-ratio 1) was cut out at an area of 5 cm square every 10 m, and the AM
It was installed under -1.5 (100 mW / cm ² ) light irradiation, and the photoelectric conversion efficiency was measured to evaluate the variation in the photoelectric conversion efficiency. Table 2 shows the results of the characteristic evaluation in which the reciprocal of the magnitude of the variation was determined based on the photovoltaic element of Comparative Example 1 (element-ratio 1).

The yield was determined by cutting out the photovoltaic elements on the belt-shaped member prepared in Example 1 (element-actual 1) and Comparative Example 1 (element-ratio 1) in an area of 5 cm square every 10 m. The shunt resistance in the dark state was measured, and those having a resistance value of 1 × 10 ³ ohm · cm ² or more were counted as non-defective products, and the ratio of all the products was expressed as a percentage and evaluated. Table 2 shows the results of the yields of the photovoltaic elements of Example 1 (element-actual 1) and Comparative Example 1 (element-ratio 1) thus determined.

[0024]

[Table 2] As shown in Table 2, the photovoltaic element of Example 1 (element-actual 1) was different from the photovoltaic element of comparative example 1 (element-ratio 1) in both of the property uniformity and the yield. Is also excellent, the photovoltaic element produced by the production method of the present invention,
It was found to have excellent properties, demonstrating the effect of the present invention.

Example 2 A procedure similar to that of Example 1 was adopted, except that the method of feeding the band member and the method of winding the interleaf in the vacuum container for feeding the band member were changed to the method shown in FIG. A single type photovoltaic element was manufactured. (Element-Actual 2) In the same procedure as in Example 1, evaluation of the uniformity of characteristics and the yield of the photovoltaic element was performed. Example 2 (element-actual 2)
Table 3 shows the results of comparison of the uniformity of the characteristics and the yield of the photovoltaic element in Comparative Example 1 with reference to Comparative Example 1 (element-ratio 1).

[0026]

[Table 3] As shown in Table 3, the photovoltaic element of Example 2 (Element-Real 2) was different from the photovoltaic element of Comparative Example 1 (Element-Comparative 1) in both the uniformity of the characteristics and the yield. Is also excellent, the photovoltaic element produced by the production method of the present invention,
It was found to have excellent properties, demonstrating the effect of the present invention.

[0027]

According to the present invention, as described above, the belt-shaped member is wound by controlling the temperature when the belt-shaped member is wound in the winding step, and in particular, by using a temperature-controllable steering roller. It is possible to reduce the slip between the steering roller and the strip, and over a large area on the continuously moving strip,
It has high photoelectric conversion efficiency, high quality, excellent uniformity, high reproducibility, and a large number of semiconductor thin films of photovoltaic elements with few defects with high yield.

[Brief description of the drawings]

FIG. 1 is a conceptual schematic diagram showing an example of a belt-shaped member winding device of the present invention.

FIG. 2 is a conceptual schematic diagram illustrating an example of a belt-shaped member winding device of the present invention.

FIG. 3 is a conceptual diagram showing an example of a continuous photovoltaic element manufacturing apparatus.

FIG. 4 is a conceptual schematic diagram of a single type photovoltaic element.

FIG. 5 is a conceptual schematic diagram showing an example of a conventional belt-shaped member winding device.

FIG. 6 is a conceptual schematic diagram showing another example of the belt-shaped member winding device of the present invention.

[Explanation of symbols]

 301, 302, 303, 304, 305: Vacuum container 306: Gas gate 307: Strip member 309: Lamp heater 310: Gas introduction tube 311: Exhaust tube 312: Cathode electrode 314: Gate gas introduction tube 315: Exhaust tube 316: Vacuum gauge 317 : Strip-shaped member feeding bobbin 318: Strip-shaped member winding bobbin 320: Steering roller 321: Eye paper winding bobbin 322: Eye paper feeding bobbin 401: SUS substrate 402: Ag thin film 403: ZnO thin film 404: First conductivity type layer 405: i-type layer 406: second conductivity type layer 407: ITO 408: current collecting electrode 501: steering roller 502: strip member 503: bobbin

Claims (4)

[Claims] The present invention is characterized in that, while continuously moving a strip-shaped member in a longitudinal direction, the strip-shaped member is passed through a plurality of film forming chambers connected by a gas gate having a gas inlet for introducing a scavenging gas into a slit-shaped separation passage. A method for forming a semiconductor thin film in which a semiconductor thin film is sequentially laminated on the belt-shaped member in a film forming chamber, and the belt-shaped member on which the semiconductor thin film is laminated is continuously wound in a winding step. A method for forming a semiconductor thin film, comprising: controlling the temperature of the belt-shaped member when winding the film. 2. The method according to claim 1, wherein the temperature control is performed by controlling a temperature of a steering roller for guiding the belt-like member to the belt-like member winding means. 3. While continuously moving the strip-shaped member in the longitudinal direction, the strip-shaped member is passed through a plurality of film forming chambers connected by a gas gate having a gas inlet for introducing a scavenging gas into a slit-shaped separation passage. A semiconductor thin film forming apparatus for sequentially laminating a semiconductor thin film on the band-shaped member in a film forming chamber and continuously winding the band-shaped member laminated with the semiconductor thin film by a band-shaped member winding means in a winding step. An apparatus for forming a semiconductor thin film, wherein a temperature control means is provided immediately before a belt-like member winding means, and the temperature of the belt-like member is controlled and wound by the temperature control means. 4. The semiconductor thin film forming apparatus according to claim 3, wherein said temperature control means is constituted by a temperature control mechanism provided on a steering roller.