JP2002060952A - Apparatus and method for forming deposited film - Google Patents

Abstract

(57) [Summary] [PROBLEMS] Even if a leak occurs in a shut-off valve, it does not cause a deterioration in characteristics, and if a flow occurs in the shut-off valve, it can be immediately detected and repaired. The present invention provides a deposited film forming apparatus and method capable of repeatedly producing a large number of functional deposited films without reproducible yields. SOLUTION: A chamber 11 whose inside can be held in a vacuum.
2, a source gas supply pipe 121 for supplying a source gas into the chamber 112, an exhaust pipe 125 for exhausting the interior of the chamber 112, and an atmosphere for supplying a gas for returning the interior of the chamber 112 to atmospheric pressure. A plurality of shut-off valves 105 and 110 are provided in series between the chamber 112 and a gas source 101 for gas for returning the pressure in the chamber 112 to the atmospheric pressure. A pressure gauge 111 and / or an exhaust unit 118 are provided between the valves 105 and 110.

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 forming a deposited film for producing a functional deposited film such as a solar cell on a substrate. In particular, the present invention relates to an apparatus and a method for producing a deposited film suitable for mass production in which a large amount of source gas is repeatedly used for a long time.

[0002]

2. Description of the Related Art Conventionally, amorphous silicon, microcrystal silicon, and the like have been proposed and put to practical use as functional deposition films for solar cells, light receiving members for electrophotography, and the like.
Various methods for producing such a material have been proposed, but a method using plasma using electromagnetic waves such as high frequency waves and microwaves is generally used.

In such a deposited film forming apparatus, a substrate for forming a functional deposited film is installed in a chamber capable of holding a vacuum, a raw material gas is introduced, and electromagnetic wave energy is added.
The source gas is decomposed and polymerized to form a deposited film on the substrate. Then, after forming the deposited film, a non-reactive gas is introduced from a pipe for introducing a gas for returning the pressure in the chamber to the atmospheric pressure, and the substrate is taken out of the chamber after returning to the atmospheric pressure. is there.

[0004]

SUMMARY OF THE INVENTION In the above-described prior art, a desired deposited film can be formed. However, there is a problem that occurs when a large amount of raw material gas is used and the apparatus is operated continuously for the purpose of producing a solar cell made of amorphous silicon for power generation. Such a deposition film forming apparatus includes a pipe for supplying a source gas, a gas supply pipe for returning the pressure in the chamber to the atmospheric pressure, and the like. Each of the shut-off valves prevents gas from being mixed. Even if a vacuum specification is used, the tightness deteriorates and the leakage (gas leakage from upstream to downstream of the shut-off valve) occurs after many uses.

Further, in the method of decomposing silane gas or the like used for forming amorphous silicon or the like, a powdery by-product called polysilane is generated, and this powder enters the shut-off valve. May shorten the life of the device. When a deposition gas is formed by introducing a raw material gas, if the gas for returning to the atmospheric pressure enters the chamber, the characteristics of the functional deposition film being formed are deteriorated. Further, it is difficult to know whether or not gas leakage has occurred at the shut-off valve, so that the yield of the deposited film may be reduced, and the cause may be reduced to reduce the operation rate of the time-consuming device.

In particular, in a low-to-roll method apparatus for mass production, the number of chambers is large, the number of shut-off valves is increased accordingly, and the probability of gas leakage increases. In addition, it is difficult to identify the shut-off valve that has caused the outflow, and it takes time to find the cause, resulting in extremely low yield and low operation rate.

[0007] The present invention provides an apparatus and a method which are effective in solving these problems.

According to the present invention, even if a gas leak occurs in the shut-off valve, the characteristics of the formed film do not deteriorate, and even if a gas leak occurs in the shut-off valve, it can be detected immediately. It is an object of the present invention to provide a deposited film forming apparatus and a forming method which can be repeatedly repaired with good reproducibility and produce a large number of functional deposited films without lowering the yield.

[0009]

According to the present invention, there is provided an apparatus for forming a deposited film, comprising: a chamber capable of holding a vacuum inside; a source gas supply pipe for supplying a source gas into the chamber;
An exhaust system pipe for exhausting the inside of the chamber, and a gas supply pipe for opening the atmosphere to supply a gas for returning the pressure in the chamber to the atmospheric pressure,

[0010] A plurality of shut-off valves are provided in series between a gas source for returning the pressure in the chamber to the atmospheric pressure and the chamber,

A pressure gauge and / or an exhaust means are provided between the plurality of shut-off valves.

According to the method of forming a deposited film of the present invention, a raw material gas is supplied into a chamber to form a deposited film on a substrate, and then a gas for opening to the atmosphere is introduced into the chamber to return the inside of the chamber to the atmosphere. In the method, a plurality of shut-off valves are provided in series between the gas source for returning the pressure in the chamber to atmospheric pressure and the chamber, and the plurality of shut-off valves are supplied while the source gas is supplied into the chamber. The film is deposited by closing the valve.

[0013]

According to the present invention, by adopting the above-described configuration of the deposited film forming apparatus, even if gas leakage occurs at the shut-off valve, the characteristics do not deteriorate and gas leakage at the shut-off valve is prevented. If it occurs, it can be immediately detected and repaired. As a result, without lowering the yield
It has become possible to produce a large number of functionally deposited films with good reproducibility.

[0014]

(Embodiment 1) An embodiment of the present invention will be specifically described with reference to FIG.

In FIG. 1, reference numeral 101 denotes a non-reactive gas for returning the pressure in the chamber 112 to the atmospheric pressure (for convenience, referred to as an "atmosphere-opening gas". (It is not necessarily released to the atmosphere.)

The non-reactive gas is supplied from the gas source 101 to the chamber 1 by a gas supply pipe 122 for opening to the atmosphere.
12 is supplied. Two shut-off valves 105 and 110 are provided on the gas supply pipe 122 for opening to the atmosphere.
A pressure gauge 111 is provided between the two shut-off valves 105 and 110. Also, if necessary, 105 and 11
It is also possible to provide an exhaust means capable of exhausting the space between the two shut-off valves 0 independently of the chamber via an exhaust shut-off valve 117 in a pipe between the shut-off valves 105 and 110.

First, the procedure for forming a deposited film using this apparatus will be specifically described. The vacuum pump 115 is started, and the exhaust shutoff valve 114 is opened. Subsequently, the automatic pressure control shutoff valve 113 is gradually opened to evacuate the chamber 112. After confirming that a sufficient vacuum state has been achieved by the pressure gauge 116, the shut-off valve 110 is opened and the shut-off valves 105 and 110
A vacuum is drawn between After confirming that the pressure is sufficiently reduced by the pressure gauge 111, the shut-off valve 110 is closed. At the same time, the value of the pressure gauge 111 is recorded.

Subsequently, after the inside of the chamber 112 is heated to a desired temperature by a heater (not shown), the source gas supply valve 109 is opened, and the secondary shutoff valve 108 and the primary shutoff valve 10 are further opened.
6 are sequentially opened, and several kinds of source gases are supplied to the source gas source 102.
To 104 through the source gas supply pipe 121 to the chamber 112.

The raw material gas is adjusted to a desired amount by the flow meter 107. Further, the automatic pressure control shut-off valve 113 is linked with a vacuum gauge 116 for measuring the pressure in the chamber, and is controlled so as to have a desired pressure.

After the pressure becomes constant, a plasma (not shown) is generated to form a deposited film on the substrate. At this time, the opening of the automatic pressure control shut-off valve 113 connected to the exhaust pipe 125 is controlled in conjunction with the pressure gauge 116 so that the pressure in the chamber does not fluctuate due to by-products accumulated in the exhaust pipe. .

After the formation of the deposited film is completed and the discharge and the heater are stopped, the secondary shutoff valve 108 and the primary shutoff valve 106 are closed to stop the supply of the source gas. Then, the automatic pressure control shutoff valve 113 is fully opened to exhaust the residual gas remaining in the chamber.

Thereafter, the shut-off valve 110 is opened and the shut-off valve 105 is opened.
Once the space between the valve and the shut-off valve 110 is evacuated once,
0 is closed, and then the shut-off valve 105 is opened and gas for returning the chamber to the atmosphere is filled up to the shut-off valve 110. Thereafter, a gas having no reactivity is introduced into the chamber by opening and closing the shutoff valve 110. After sufficient replacement with this gas, the shut-off valve 114 is subsequently closed, and the non-reactive gas 101 is introduced into the chamber 112 to bring the pressure in the chamber 112 to atmospheric pressure. After the atmospheric pressure is reached, the door provided in the chamber (not shown) is opened, that is, the deposited film is taken out by opening to the atmosphere.

The deposited film is formed by the above procedure.

In addition to the above, during the formation of the deposited film, the exhaust shutoff valve 117 is opened with the shutoff valves 105 and 110 closed, and the shutoff valve 1 is opened by the exhaust means (vacuum pump) 118.
It is also possible to evacuate between 05 and 110. Thus, the pipe 122 independent of the exhaust means of the chamber
Exhaust means for the shut-off valves 105 and 1
By evacuating the space between 10 and 10, the effect of the present invention becomes more remarkable. In addition, it is possible to prevent gas leakage even if there is no pressure gauge by exhausting in this way.

Further, in FIG. 1, two pipes, a pipe for introducing a raw material gas into the chamber and a pipe for introducing a non-reactive gas for returning the pressure in the chamber to the atmospheric pressure, are separately provided. However, in order to simplify the configuration of the apparatus, these two pipes are connected via a shut-off valve before connecting to the chamber, and the pipe to the chamber is reduced to one. good.

In the present invention, any source gas may be used for forming the deposited film. For example, when an amorphous silicon film or a microcrystalline silicon film is deposited, silane (SiH ₄ ) and disilane (Si ₂ H ₆ ) are used. ,
Silicon tetrafluoride (SiF ₄ ), disilicon hexafluoride (Si ₂ F ₆ ), or the like is used as a source gas, and nitrogen (N ₂ ), ammonia (NH ₃ ), or the like is used to change the band gap width. Elements containing atoms, oxygen (O ₂ ), carbon monoxide (C
O), carbon dioxide (CO ₂ ), methane (CH ₄ ), germanium (GeH ₄ ), etc., or diborane (B ₂ H ₆ ), boron fluoride (BF ₃ ), phosphine (PH ₃ ) etc. may be simultaneously introduced into the chamber.

As the non-reactive gas used to return the pressure in the chamber to the atmospheric pressure in the present invention, a non-toxic gas that is not reactive with the raw material gas and air and has low toxicity is used. Specifically, dry nitrogen, helium, and argon are preferable, and if the source gas does not react with air, dry air is preferable.

The exhaust pump used in the present invention is preferably a dry pump or a rotary pump. It is also important to introduce a gas slowly and exhaust slowly so that the generated polysilane and the like are not easily diffused from the chamber to the shutoff valve further upstream. Here, slow introduction and slow exhaust mean that by opening and closing the valve slowly, care is taken not to suddenly move a large amount of gas, so that dust etc. existing in the pipes and chambers are not blown away. It is to be.

The shut-off valve used in the present invention is of a vacuum specification and is preferably one that can withstand repeated use. In addition, in the case of a deposition film forming device that easily produces powdery by-products such as polysilane, it is effective to put a filter on the chamber side of the shut-off valve so that powdery substances do not enter the shut-off valve. It is.

The pressure gauge used in the present invention only has to be a vacuum gauge, and it is preferable that the pressure gauge can measure several atmospheric pressures accurately from a vacuum state. Further, in the case of automatically operating by a program, a pressure gauge (a pressure gauge with an alarm contact) having a function of issuing an alarm when a certain pressure is reached is more preferable.

(Embodiment 2) FIG. 2 shows another embodiment. The deposited film forming apparatus of this example includes a plurality of chambers 202 and 20.
This is a solar cell mass-production apparatus having the reference numerals 3 and 204, and is an apparatus for repeatedly producing an amorphous silicon solar cell having a three-layer configuration of nip / nip / nip by a roll-to-roll method.

Reference numeral 206 denotes a gas source for returning the pressure in the chamber to the atmospheric pressure, and a main air supply gas supply pipe 215 is connected to the gas source 206 via a shut-off valve 210. Further, from the main gas supply pipe 215 for opening to the atmosphere, each of the chambers 202, 203, 204
The branching officers are branched toward, and each branch pipe is provided with a shutoff valve 20.
7 are connected to the chambers 202, 203, and 204.

Further, a pressure gauge 211 is provided at a position downstream of the shutoff valve 210 of the main gas supply pipe for opening to the atmosphere.

In this embodiment, the manual shutoff valves 212 and 21 are provided at appropriate positions on the main gas supply pipe 215 for opening to the atmosphere.
3 is provided.

Further, the primary shutoff valve and the second shutoff valve, which are features of the present invention, are provided.
Regarding the arrangement of the next shut-off valve, in the case of this embodiment in which the chamber branches into many chambers as shown in FIG. 2, it is also effective to insert some manual valves in the middle of the branch pipe. This manual valve is normally left open, and is used to identify which of the shut-off valves is leaking gas after confirming that one of the shut-off valves has gas leak by the method of the present invention. . The block is divided into several blocks by a manual valve, and a shut-off valve in which gas leakage occurs can be narrowed down depending on which manual valve opens and closes and the pressure changes when the manual valve is opened and closed.

[0036]

EXAMPLES Examples and comparative examples for demonstrating the effects of the present invention will be shown below.

(Comparative Example) An amorphous silicon solar cell having a three-layer structure of nip / nip / nip was repeatedly produced using the conventional solar cell mass production apparatus shown in FIG.
A method for forming a deposited film will be described with reference to the drawings.

First, all the chambers are opened to the atmosphere,
The inside of each chamber is cleaned, and a roll-shaped substrate (a substrate wound on a roll is set in the substrate unwinding chamber 301. Then, a plurality of deposition film forming chambers 302 to 30 are formed.
The belt-shaped substrate 308 from which the roll-shaped substrate is drawn out to the substrate take-up chamber 305 through the slit 309 and the slit-shaped space 309 is set. Thereafter, the doors of all chambers are closed, and the inside of all chambers is evacuated by a rotary pump (not shown). After the chamber is heated by a heater (not shown) provided in each chamber and sufficiently baked out, a suitable flow rate of a raw material gas is supplied into each chamber from a raw gas supply pipe (not shown). Electric power for generating plasma suitable for the inside was supplied, and an amorphous silicon solar cell having a three-layer structure was formed on a roll-shaped substrate moving at a constant speed. After all the belt-shaped substrates were wound into the substrate winding chamber 305, the power supply for plasma generation in each chamber was stopped, the raw material gas was supplied, and the heater for heating each chamber was stopped. After sufficiently cooling the chamber, dry nitrogen is supplied from the gas source 306 as a non-reactive gas from the gas source 306, and by opening and closing the shutoff valve 307, the residual gas accumulated in each chamber and each exhaust pipe is pushed out. The shut-off valve of the exhaust pipe for exhausting the inside was closed, and a non-reactive gas was supplied into the chamber to return the pressure in the chamber to the atmospheric pressure. After returning to the atmospheric pressure, the roll winding chamber 306 was opened, and the roll substrate on which the film deposition was completed was taken out.

Then, each chamber was cleaned, a new belt-like substrate was set, and film deposition was continued under the same conditions. The rolled substrate taken out was subjected to the next step of forming a transparent conductive film, and evaluated as a solar cell. Evaluation is 1
With respect to a roll (one of the belt-shaped substrates wound in a roll), ten points are selected at equal intervals in the length direction of the belt-shaped substrate, the conversion efficiency is measured, and the average of the ten points is used as the initial conversion efficiency of the roll. did. Thus, the production of the amorphous silicon solar cell was continued for three months.

FIG. 4 shows the evaluated solar cell characteristics as relative values of the initial conversion efficiency for each roll (160 rolls are defined as 1). As shown in FIG. 4, it can be seen that a decrease in efficiency starts to be seen from about 187 rolls, and a characteristic decrease becomes significant from about 200 rolls. After making 212 rolls, the apparatus was stopped for investigating the cause, and various investigations for investigating the cause were performed. As a result of the investigation for about two weeks, it was found that a gas leak occurred in one of the shut-off valves 307 in the apparatus shown in FIG. Then, the shut-off valve was replaced, the film was deposited, and the characteristics were evaluated. As a result, a good initial conversion efficiency was obtained.

Example 1 An amorphous silicon film was deposited on a SUS substrate by supplying 150 sccm of silane gas and 1000 sccm of hydrogen gas using the apparatus shown in FIG. A deposited film was repeatedly formed by the procedure shown in the above embodiment. In addition, the exhaust by the exhaust means 118 was also performed. After 300 repetitions, the pressure gauge 211 between the shut-off valves turned from 0 mTorr to 10
rr. After the film formation, the shut-off valve was removed from the pipe, and the inspection revealed that gas leakage had occurred. When the electrical characteristics were examined using an amorphous silicon film formed at the time of gas leakage as a single film, a good film was obtained.

Example 2 A solar cell was repeatedly produced by the apparatus for producing an amorphous silicon solar cell by the roll-to-roll method shown in FIG. The preparation procedure is the same as that of the comparative example. However, two manual valves 212 and 213 are provided in a gas-reactive gas pipe for returning the pressure in the chamber to the atmospheric pressure, which is a feature of the present invention, and the pipe can be divided into three blocks. . The pressure gauge 210 was set so that an alarm contact was set at 10 Torr, and an alarm was issued when the pressure exceeded 10 Torr during 15 hours during film deposition. Using this apparatus, a solar cell was repeatedly produced, and the solar cell characteristics were evaluated in the same manner as in the comparative example. The result is shown in FIG. 2 in the figure
No problem before 00 roll, so omit 2
The values from 00 roll to 260 roll are shown. Good initial conversion efficiencies were obtained. An alarm was issued because the pressure gauge 211 exceeded 10 Torr when a 227 roll deposited film was formed. After the formation of the deposited film of 227 rolls was completed, a specific operation of the shut-off valve leaking gas was performed. First, the manual shutoff valve 210 was closed to make a vacuum between the shutoff valves 210 and 207. Next, the manual shutoff valve 213 was closed and left for several hours. When the pressure gauge 211 was monitored, the pressure increased to about 10 Torr. Next, with the manual shut-off valve 212 closed, the pressure gauge 2
Monitoring of 11 showed no increase in pressure this time. From the above, it was found that gas leakage occurred in any of the three manual valves 207 in the pipe between the manual shutoff valves 212 and 213. When the three shut-off valves were removed and investigated, it was found that one of the 207s had a gas leak, so the shut-off valves were replaced. As described above, the replacement work of the shutoff valve was performed. The characteristics of the solar cell produced at that time were also good.

[0043]

According to the present invention, by using the above-described apparatus for forming a deposited film, even if an outflow occurs in the shut-off valve, the characteristics are not deteriorated even if the outflow occurs. When a flow occurs, it can be detected immediately and repaired, and as a result, a large number of functional deposited films can be repeatedly produced with good reproducibility without lowering the yield.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of a deposited film forming apparatus according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram of a deposited film forming apparatus according to another embodiment of the present invention.

FIG. 3 shows a conventional roll-to-roll deposition film forming apparatus.

FIG. 4 is a graph showing characteristics when film deposition is repeated by a conventional method.

FIG. 5 is a graph showing characteristics when film deposition is repeated by a method according to an example of the present invention.

[Explanation of symbols]

101 Non-reactive gas source (gas source for opening to the atmosphere) 102 to 104 Source gas 105, 110 Shut-off valve 106 Primary shut-off valve 107 Flow meter 108 Secondary shut-off valve 109 Source gas supply valve 111, 116 Pressure gauge 112 Chamber 113 Automatic pressure control shut-off valve 114, 117 Exhaust shut-off valve 115, 118 Vacuum pump 121 Source gas supply pipe 122 Gas supply pipe for opening to atmosphere 125 Exhaust system pipe 201, 301 Substrate unwinding chamber 202, 302 n-layer forming chamber 203, 303 i Layer forming chamber 204, 304 P layer forming chamber 205, 305 Substrate winding chamber 206, 306 Non-reactive gas 207 Secondary shutoff valve 215 Gas supply pipe for opening to the atmosphere 216 Branch pipe 307 Shutoff valve 207 ', 307' Leakage The generated shut-off valve 208 308 rolled substrate 309 slit-like gap 210 primary shut-off valve 211 pressure gauge 212 manual shut-off valve 213 manually shut-off valve

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Hiroshi Izawa 3-30-2 Shimomaruko, Ota-ku, Tokyo F-term in Canon Inc. (reference) 4G075 AA24 BC04 CA47 CA63 CA65 DA01 EB01 EC25 4K030 AA04 AA06 AA10 AA13 AA14 AA17 AA18 BA29 BA30 BB04 CA17 EA03 EA11 GA14 KA08 KA39 KA41 KA49 LA16 5F045 AB04 AC01 AC02 AC12 AC15 AC16 AC17 AC19 BB08 BB15 CA13 DP22 EF18 5F051 AA05 BA14 CA16 CA22 DA04 DA17

Claims (9)

[Claims] A chamber capable of holding a vacuum inside;
A source gas supply pipe for supplying a source gas into the chamber, an exhaust pipe for exhausting the inside of the chamber, and an atmospheric gas supply for supplying a gas for returning the pressure in the chamber to atmospheric pressure A plurality of shut-off valves are provided in series between the gas source for returning the pressure in the chamber to atmospheric pressure and the chamber, and a pressure gauge and a pressure gauge are provided between the plurality of shut-off valves. And / or an apparatus for forming a deposited film, wherein an exhaust means is provided. 2. An apparatus according to claim 1, wherein said exhaust means is independent of an exhaust means for exhausting the inside of the chamber. 3. The apparatus according to claim 1, wherein the chamber includes a plurality of chambers. 4. The deposition film forming apparatus according to claim 3, wherein the gas supply pipe for opening to the atmosphere is branched toward a plurality of chambers, and a manual valve is provided in the middle of the branched pipe. 5. The apparatus according to claim 1, wherein the apparatus is programmed to automatically perform film deposition. 6. The deposited film forming apparatus according to claim 5, wherein the pressure gauge is a pressure gauge with an alarm contact. 7. A method for forming a deposited film on a substrate by supplying a source gas into a chamber and introducing a gas for opening to the atmosphere into the chamber to return the inside of the chamber to atmospheric pressure. A plurality of shut-off valves are provided in series between the gas source for returning the pressure to the atmospheric pressure and the chamber, and while supplying the source gas into the chamber, the shut-off valves are closed to deposit the film. A film deposition method. 8. The method according to claim 7, wherein the pressure is reduced between the plurality of shut-off valves to deposit the film. 9. The method according to claim 7, wherein the non-reactive gas is filled between the plurality of shut-off valves to perform film deposition.