JP2006165223A - Substrate treatment method and equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a production facility having the high uniformity and reproducibility of device characteristics of a solar cell or the like, by suppressing unevenness in treatment and characteristics resulting from the deformation of a substrate shape in a treatment space. <P>SOLUTION: In the substrate treatment method where a substrate is carried into a treatment space and the surface of the substrate is treated, the deflection of the substrate carried into the treatment space is detected by a sensor 110 and controlled based on the detected deflection before the substrate is carried into the treatment space. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method and an apparatus for performing processing on a substrate, for example, a vacuum processing method and a vacuum processing method for mass-producing photovoltaic elements using amorphous silicon.

  Conventionally, a vacuum processing apparatus has been widely used for producing photoelectric conversion elements such as solar cells, and the following techniques are known as methods for producing solar cells.

  For example, in general, a plasma CVD method is widely used and practically used for manufacturing a solar cell using a non-single-crystal semiconductor film or the like. However, solar cells are basically required to have sufficiently high photoelectric conversion efficiency, excellent characteristics stability, and capable of mass production. To that end, in the production of solar cells using non-single crystal semiconductor films, etc., the electrical, optical, photoconductive or mechanical characteristics, and the fatigue characteristics in repeated use or the environmental characteristics of use are improved. In addition, it is necessary to achieve mass production with high reproducibility by high-speed film formation while achieving large area, uniform film thickness and film quality, and these are pointed out as problems to be improved in the future. .

  In the power generation method using solar cells, the unit modules are connected in series or in parallel to form a unit to obtain the desired current and voltage, and no disconnection or short circuit occurs in each module. Is required. In addition, it is important that there is no variation in output voltage or output current between modules. For this reason, it is required that the characteristic uniformity of the semiconductor layer itself, which is the largest characteristic determining element, is secured at least at the stage of manufacturing the unit module. From the viewpoint of facilitating module design and simplifying the module assembly process, the provision of a semiconductor deposited film with excellent characteristic uniformity over a large area increases the mass productivity of solar cells and increases the production cost. Is required to achieve a significant reduction in

As for the solar cell, the semiconductor layer, which is an important constituent element, has a semiconductor junction such as a so-called pn junction or pin junction. When a thin film semiconductor such as a-Si is used, glow discharge decomposition is performed by mixing silane (SiH ₄ ), which is a source gas containing an element serving as a dopant such as phosphine (PH ₃ ), diborane (B ₂ H ₆ ), or the like. Thus, it is known that a semiconductor film having a desired conductivity type can be obtained, and that the above-described semiconductor junction can be easily achieved by sequentially laminating these semiconductor films on a desired substrate. From this, for the production of a non-single-crystal semiconductor solar cell, there is a method of providing an independent film formation chamber for manufacturing each semiconductor layer and manufacturing each semiconductor layer in the film formation chamber. Proposed.

  For example, Patent Document 1 discloses a continuous plasma CVD apparatus that employs a roll-to-roll method. According to this apparatus, a plurality of glow discharge regions are provided, a flexible substrate having a sufficiently long desired width is deposited, and the substrate deposits a conductive type semiconductor layer required in each of the glow discharge regions. It is said that a device having a semiconductor junction can be continuously manufactured by continuously transporting the substrate in the longitudinal direction.

U.S. Pat. No. 4,400,409

  However, the above-described roll-to-roll method and the conventional method for forming a deposited film in a vacuum processing apparatus have the following problems.

  First, there is a problem that the substrate is bent in the deposition chamber, the flow of the film forming gas in the deposition chamber becomes non-uniform, and there is a big difference in the generation of active species that are important factors in the deposition process. It is left. In other words, it has been left as a defect for the purpose of uniform film deposition over a large area. In particular, in the case of a film with a very delicate production process such as a microcrystal, the flow rate difference of the film forming gas as described above has been a fatal problem.

  Secondly, when depositing a film with extremely severe film formation conditions (high discharge power, high dilution gas flow rate, etc.) like a microcrystal film, abnormal discharge is induced in the plasma due to deformation of the substrate shape. There was a problem of causing defective products over the entire space.

  For this reason, the method for forming a deposited film by the roll-to-roll method is particularly suitable for mass production of semiconductor devices. However, as described above, in order to popularize solar cells in large quantities, further photoelectric conversion efficiency Therefore, improvement of characteristic stability and characteristic uniformity, improvement of apparatus operation rate, and reduction of manufacturing cost are desired.

  Moreover, in order to improve photoelectric conversion efficiency and characteristic stability, the higher the photoelectric conversion efficiency for each unit module, the better, and the lower the characteristic deterioration rate, the better. Furthermore, when unit modules are connected in series or in parallel and unitized, the unit module of the minimum current or voltage characteristics of each unit module constituting the unit is rate-determined, and the unit characteristics are determined. It is very important not only to improve the average characteristic of each unit module but also to reduce the characteristic variation. Therefore, it is desired to ensure the uniformity of the characteristics of the semiconductor layer itself, which is the largest characteristic determining factor at the stage of manufacturing the unit module.

  SUMMARY OF THE INVENTION Accordingly, the present invention aims to solve the various problems associated with processing such as film formation on a substrate as described above, and to realize a method and apparatus capable of uniform substrate processing in a processing space. Is.

  As a result of intensive studies on the cause of the deflection of the substrate in the processing space, the inventors have found that the substrate (especially those having a large thermal expansion coefficient) are greatly affected by temperature changes during each processing step and the transfer step. I found out. Specifically, if the temperature change or temperature non-uniformity occurs in the substrate processing process or transport process, the thermal expansion (shrinkage) amount varies depending on the location of the substrate, and as a result, the entire substrate It has been found that deflection occurs and a conclusion is reached that the process is greatly adversely affected.

The present invention has been made based on the above knowledge, and in a substrate processing method for carrying a substrate surface into a processing space and processing the substrate surface, based on the amount of deflection of the substrate carried into the processing space, The substrate is carried into the processing space after the deflection amount of the substrate is controlled.
The substrate processing method of the present invention is as follows.
"Processing of the substrate surface is a plasma CVD process",
“The treatment of the substrate surface is a method of treating the substrate by applying power to the electrode disposed opposite to the substrate, and the distance between the electrode and the substrate is in the range of 1 mm to 70 mm.”
“Processing of the substrate surface is a sputtering process”
"The means for controlling the amount of deflection of the substrate is one using a heat source",
“Detecting the amount of deflection of the substrate with a sensor, and controlling the amount of deflection of the substrate based on the detected amount of deflection”,
“Predicting the relationship between the amount of deflection of the substrate in the processing space and the processing time, and controlling the amount of deflection of the substrate based on the predicted amount of deflection of the substrate, and then loading the substrate into the processing space. "
"The substrate is a strip-shaped long substrate",
“Controlling the amount of deflection of the substrate to a range of 0.5 mm to 4.0 mm”,
Is included as a preferred embodiment thereof.

According to the present invention, in a substrate processing apparatus for processing a substrate surface by loading a substrate into the processing space, means for detecting a deflection amount of the substrate carried into the processing space, and controlling the deflection amount of the substrate. It has the means.
The substrate processing apparatus of the present invention described above,
“Having means for disposing an electrode facing the substrate in the processing space, and the distance between the electrode and the substrate is in a range of 1 mm to 70 mm.”
"The means for controlling the amount of deflection of the substrate is one using a heat source",
“Having means for storing the detected amount of deflection of the substrate”;
Is included as a preferred embodiment thereof.

According to the present invention, it is possible to suppress the deformation of the substrate shape in the processing space, and to suppress the processing unevenness / characteristic unevenness caused by the unevenness of the shape at the center and end portions of the substrate, particularly during the substrate processing step. Uniform substrate processing is possible within the processing space, and in particular, production equipment with high uniformity and reproducibility of device characteristics such as solar cells can be realized.
In addition, according to the present invention, when a microcrystal i-type semiconductor layer having a severe film forming condition is formed on a substrate in manufacturing a solar cell or the like, an abnormal discharge that causes a fatal defect to the device itself is induced. Substrate processing can be performed without the need to perform the manufacturing process, leading to an improvement in the operating rate of the apparatus and an improvement in yield, and a production facility capable of reducing production costs.

Embodiment examples of the present invention will be described below.
FIG. 1 is a schematic view showing a vacuum processing apparatus as an example of the substrate processing apparatus of the present invention. This vacuum processing apparatus (plasma CVD apparatus) 100 mainly includes an outer container 102, a processing chamber 103, a gas manifold 104, an electrode 105, an exhaust passage 107, an O-ring 108, and a heater unit 109 for controlling the deflection amount of the substrate. , Substrate displacement sensor 110, high-frequency power source 111, substrate transport unit 112, substrate holder 113 holding substrate 101, processing gas introduction valve 114, processing chamber wall heater 115, substrate heater unit 116, shutter 117, substrate The temperature control thermocouple 118, the processing chamber wall temperature control thermocouple 119, and the substrate displacement sensor transmission window 120 are configured.

  The substrate displacement sensor 110 detects the amount of deflection of the substrate 101 before being carried into the processing chamber 103. The heater unit 109 is composed of a large number of heaters arranged in a plane, and supplies power by selecting an arbitrary region based on the substrate deflection amount (deflection amount distribution) detected by the substrate displacement sensor 110. It is configured to be able to.

  When a film is formed on the substrate 101 using the vacuum processing apparatus shown in FIG. 1, the substrate is heated to, for example, near the film formation temperature in the processing chamber before the substrate 101 is transferred to the processing chamber 103. Then, the substrate displacement sensor 110 detects the deflection amount of the substrate. Then, power is supplied to an arbitrary region of the heater unit 109 based on the detection result to control the amount of deflection of the substrate, and then the substrate is introduced into the processing chamber 103 to perform film formation. Thus, by controlling the deflection amount of the substrate in advance, it is possible to suppress the deformation of the substrate shape in the processing chamber.

  In addition, when the relationship between the amount of deflection of the substrate in the processing chamber and the processing time can be predicted from the past database, the heater unit is not detected by the substrate displacement sensor 110 as described above. The amount of deflection of the substrate can be controlled by 109.

FIG. 3 is a schematic view of a continuous plasma CVD apparatus that employs a roll-to-roll method, which is another example of the substrate processing apparatus of the present invention. The continuous plasma CVD apparatus 300 includes a sending container 302 and a winding container 303 for a strip-shaped substrate 301, an n-type semiconductor layer film forming container 304, an i-type semiconductor layer film forming container 305, an H ₂ plasma processing container 306, and a p-type semiconductor layer. The apparatus includes a film forming container 307 connected via a gas gate 315. Reference numeral 308 denotes a delivery bobbin for the belt-like substrate 301, and 309 denotes a take-up bobbin for the belt-like substrate 301. The belt-like substrate 301 is conveyed in the direction of arrow B in the figure. However, the belt-like substrate 301 can be transported while being reversed. Further, a slip-up and feeding means used for protecting the surface of the belt-like substrate 301 may be disposed in the feeding container 302 and the winding container 303. As the material of the interleaf paper, a heat resistant resin such as polyimide, Teflon (registered trademark), glass wool or the like is preferably used. Reference numerals 310 and 311 denote transport rollers that also serve as tension adjustment and positioning of the belt-like substrate 301. Reference numeral 313 denotes a conductance adjusting throttle valve, and 312 denotes an exhaust pipe, which is connected to an exhaust pump (not shown).

  In each of the film forming containers 304, 305, 306, and 307, the processing chamber 321 and the heater unit are disposed to face each other with the band-shaped substrate 301 interposed therebetween. In the processing chamber 321, an electrode 318 connected to the RF power source 314 is disposed so as to face the strip substrate 301. The main flow direction of the gas in each processing chamber is indicated by an arrow A. The heater unit is provided with a number of infrared lamp heaters 319 and a lamp house 320 for efficiently concentrating radiant heat from the infrared lamp heaters on the belt-like substrate 301. Further, a thermocouple 317 for monitoring the temperature of the strip substrate 301 is provided. Reference numeral 322 denotes a processing chamber heater, and 323 denotes a gas introduction pipe.

  Further, in each of the film forming containers 304, 305, 306, and 307, a substrate displacement sensor 324 and a heater unit 326 for controlling the deflection amount of the substrate are disposed on the upstream side of the processing chamber 321 with the band-shaped substrate 301 interposed therebetween. Opposed to each other. Reference numeral 325 denotes a substrate deformation monitor thermocouple.

  The substrate displacement sensor 324 detects the amount of deflection of the belt-like substrate 301 before being carried into the processing chamber 321. The heater unit 326 includes a large number of heaters arranged in a plane. The substrate displacement sensor 324 and the heater unit 326 are connected to a substrate deformation heating temperature control device (not shown). The amount of deflection of the substrate detected by the substrate displacement sensor 324 is stored in the storage means of the substrate deformation heating temperature control device, and based on this value, an arbitrary region of the heater unit 326 is selected to supply power.

  When the strip-shaped substrate 301 is processed using the continuous plasma CVD apparatus shown in FIG. 3, the deflection amount of the strip-shaped substrate 301 is detected by the substrate displacement sensor 324 on the upstream side of the processing chamber 321. And based on this detection result, electric power is supplied to the arbitrary area | region of the heater unit 326, and the deflection amount of a strip | belt-shaped board | substrate is controlled. In this way, by controlling the amount of deflection of the belt-shaped substrate in advance, the deformation of the substrate shape in the processing chamber can be suppressed, and it has high quality and excellent uniformity on the continuously moving belt-shaped substrate. A photovoltaic device with few defects can be manufactured.

  The present invention is particularly effective when a substrate is processed by applying electric power to an electrode disposed in close proximity to the substrate. In other words, the closer the distance between the electrode and the substrate, the greater the influence of the substrate deflection, and the greater the processing unevenness / characteristic unevenness. Therefore, the amount of substrate deflection can be controlled in advance to suppress the deformation of the substrate shape in the processing chamber. The effect is great. Specifically, the present invention can be particularly suitably used when the distance between the electrode and the substrate is in the range of 1 mm to 70 mm.

  Further, in the present invention, although it depends on the processing method, the distance between the electrode and the substrate, etc., it is preferable to control the deflection amount of the substrate in the range of 0.5 mm to 4.0 mm. When the amount of deflection is less than 0.5 mm, it is rare that processing unevenness / characteristic unevenness is originally a problem, and it is not impossible to control to less than 0.5 mm. It tends to increase. On the other hand, when the amount of deflection exceeds 4.0 mm, the processing unevenness and the characteristic unevenness cannot be sufficiently suppressed.

  Next, a specific configuration of a solar cell that can suitably use the present invention will be described below. FIG. 2 is a schematic diagram showing a typical configuration example of a solar cell. A solar cell 201 shown in FIG. 2 includes a conductive substrate 202, a lower electrode 203, an n-type semiconductor layer 204, an i-type semiconductor layer 205, a p-type semiconductor layer 206, a transparent electrode 207, a collecting electrode 208, and an extraction electrode 209. Therefore, it is assumed that light enters through the transparent electrode 207. Below, the component of this solar cell is demonstrated.

(substrate)
The constituent material of the substrate 202 preferably has a desired strength with little deformation and distortion at the temperature required when the semiconductor layer is manufactured. Specifically, stainless steel, aluminum and alloys thereof, iron and alloys thereof Sputtering a thin metal plate such as copper and its alloy and a composite thereof, and a metal thin film of a different material on the surface thereof, or an insulating thin film such as SiO ₂ , Si ₃ N ₂ , Al ₂ O ₃ , AlN ₃ , Surface coating treatment by vapor deposition method, plating method, etc. In addition, the surface of a heat-resistant resin sheet such as polyimide, polyamide, polyethylene terephthalate, and epoxy, or a composite of these with glass fiber, carbon fiber, boron fiber, metal fiber, etc., a simple metal or alloy, and transparent conductive oxide (TCO) etc. which performed the electroconductive process by methods, such as plating, vapor deposition, a sputtering, application | coating, are mentioned.

  In addition, the thickness when the substrate is used in the form of a strip is as thin as possible in consideration of cost, storage space, etc., as long as it is within the range where the strength maintained at the time of transport by the substrate transport means is exhibited. Is preferred. Specifically, the thickness is preferably 0.01 mm to 5 mm, more preferably 0.02 mm to 2 mm, and most preferably 0.05 mm to 1 mm. However, when using a thin plate such as a metal, the thickness is compared. Even if the thickness is reduced, a desired strength can be easily obtained.

  The width of the belt-like substrate is not particularly limited, and is determined by the size of the semiconductor layer manufacturing means or its container. Further, the length of the belt-like substrate is not particularly limited, and may be a length that can be wound up in a roll shape, which is obtained by further elongating a long one by welding or the like. May be. Further, the surface property of the conductive strip substrate may be a so-called smooth surface or a minute uneven surface. In the case of a minute uneven surface, it is spherical, conical, pyramidal, etc., and its maximum height (Rmax) is preferably 50 nm to 500 nm, so that light reflection on the surface becomes irregular reflection. The optical path length of the reflected light at the surface is increased.

(electrode)
In the solar cell, an appropriate electrode is selectively used depending on the configuration form of the device. Examples of those electrodes include a lower electrode, an upper electrode (transparent electrode), and a current collecting electrode (however, the upper electrode referred to here means one provided on the light incident side, and the lower electrode is It shall refer to that provided opposite to the upper electrode with the semiconductor layer in between.)

  As a constituent material of the lower electrode suitably used for the solar cell, metals such as Ag, Au, Pt, Ni, Cr, Al, Ti, Zn, Mo, and W or alloys thereof can be cited. The lower electrode can be formed by a film forming means such as vacuum evaporation, electron beam evaporation, or sputtering using these metals. The metal thin film formed at that time must be considered not to be a resistance component with respect to the output of the solar cell, and the sheet resistance value is preferably 50Ω or less, more preferably 10Ω or less.

  Although not shown in the drawing between the lower electrode 203 and the n-type semiconductor layer 204 (or p-type semiconductor layer), a buffer layer for preventing a short circuit such as ZnO or buffering the electrode metal may be provided. Good. The effect of the buffer layer is not only to prevent the metal element constituting the lower electrode 203 from diffusing into the n-type semiconductor layer (or p-type semiconductor layer), but also to provide a slight resistance value so that the semiconductor layer Between the lower electrode 203 and the upper (transparent) electrode 207 provided across the electrode, preventing a short-circuit caused by a defect such as a pinhole, and generating multiple interference due to a thin film and allowing incident light to enter the solar cell And the like.

  Suitable materials for constituting the buffer layer include magnesium fluoride-based materials, indium, tin, cadmium, zinc, antimony, silicon, chromium, silver, copper, aluminum oxides, nitrides and carbides, or these The material chosen from the mixture of these is mentioned. In particular, magnesium fluoride and zinc oxide are preferable because they are easy to form and have an appropriate resistance value and light transmittance as a buffer layer.

The transparent electrode 207 preferably has a light transmittance of 70% or more and more preferably 80% or more in order to efficiently absorb light from the sun, a white fluorescent lamp, or the like into the semiconductor layer. Examples of materials having such characteristics include metal oxides such as SnO ₂ , In ₂ O ₃ , ZnO, CdO, Cd ₂ SnO ₄ , ITO (In ₂ O ₃ + SnO ₂ ), and metals such as Au, Al, and Cu. And a thin metal film formed in a semi-transparent form. The transparent electrode is laminated on the p-type semiconductor layer 206 (or n-type semiconductor layer) in the solar cell having the configuration as shown in FIG. As these manufacturing methods, a resistance heating vapor deposition method, a sputtering method, a spray method, or the like can be used, and is appropriately selected as desired.

  The collecting electrode 208 is provided on the transparent electrode 207 for the purpose of reducing the sheet resistance value of the transparent electrode 207. In the solar cell having the configuration as shown in FIG. 2, since the transparent electrode is formed after the semiconductor layer is formed, the substrate temperature at the time of forming the transparent electrode cannot be increased so much, and the sheet resistance value of the transparent electrode In particular, it is preferable to form the current collecting electrode 208 because the current collector electrode 208 must be relatively high.

  As a constituent material of the current collecting electrode, simple metals such as Ag, Cr, Ni, Al, Au, Ti, Pt, Cu, Mo, and W, alloys thereof, or carbon can be cited. In addition, the advantages of these metals or carbon (low resistance, low diffusion to the semiconductor layer, robustness, easy electrode formation by printing, etc.) can be used in combination. Further, in order to ensure a sufficient amount of light incident on the semiconductor layer, the shape is uniformly spread with respect to the light receiving surface of the solar cell, and the area is preferably 15% or less, more preferably with respect to the light receiving area. Is preferably 10% or less. Further, the sheet resistance value is preferably 50Ω or less, more preferably 10Ω.

(Semiconductor layer)
As a semiconductor material constituting an i-type semiconductor layer suitably used in a solar cell, a-Si: H, a-Si: F, a-Si: H: F, a-SiC: H, a-SiC: F, a-SiC: H: F, a-SiGe: H, a-SiGe: F, a-SiGe: H: F, polycrystalline Si: H, polycrystalline Si: F, polycrystalline Si: H: F And so-called group IV and group IV alloy semiconductor materials. The amount of hydrogen atoms contained in the i-type semiconductor layer is preferably 20 atomic percent or less, more preferably 10 atomic percent or less.

  The semiconductor material constituting the p-type or n-type semiconductor layer suitably used in the solar cell can be obtained by doping the semiconductor material constituting the i-type semiconductor layer with a valence electron controlling agent. It is preferable to include a crystal layer in the semiconductor material constituting the type semiconductor layer because the utilization factor of light and the carrier density can be increased. Further, the hydrogen concentration contained in the p-type or n-type semiconductor layer is preferably 5 atomic% or less, and more preferably 1 atomic% or less.

The semiconductor layer forming source gas used when forming these semiconductor layers is a simple substance of the constituent elements of the various semiconductor layers described above, a hydride, a halide, an organometallic compound, etc. Those that can be introduced are preferably used. Of course, these source gases can be used not only in one kind but also in a mixture of two or more kinds. These source gases may be introduced in a mixture with a rare gas such as He, Ne, Ar, Kr, Xe, or Rn and a diluent gas such as H ₂ , HF, or HCl.

  Specific examples of the present invention will be described below, but the present invention is not limited to these examples.

[Example 1]
An amorphous silicon semiconductor film was formed on a 30 cm square glass substrate using the vacuum processing apparatus shown in FIG.

  Regarding the substrate, in order to improve the operation rate of the apparatus, preheating was performed in advance before the processing chamber was carried in. As the heating method, electric power was supplied to the heater unit 109 while confirming the amount of deflection of the substrate by the substrate displacement sensor 110, and the temperature was adjusted to 200 ° C., which is the optimum temperature for film deposition in the processing chamber. At that time, since the amount of deflection of the substrate at the central portion of the substrate was 2 mm, power was supplied only to the outer peripheral portion of the heater unit 109 so that only the peripheral portion of the substrate was 220 ° C. As a result, the amount of deflection of the substrate was 1 mm or less.

Thereafter, the substrate was introduced into the processing chamber 103, and SiH ₄ and H ₂ were used as the deposition film forming source gas. The pressure was set to 200 Pa, and high frequency power was applied to the electrode 105 from a high frequency power source (27 MHz) 111 to cause discharge. After the discharge was stabilized, the shutter 117 was opened, and an amorphous silicon film was deposited to 2 μm on the 30 cm square glass substrate. After deposition, the shutter 117 was closed and the substrate was replaced. The deposition film formation time required per trial was 90 minutes.

  This trial was repeated 100 times in succession, and arbitrarily extracted five samples were divided into two on the gas introduction side and the exhaust port side, and the film thickness was examined. Moreover, Cr / Ag was vapor-deposited in the shape of a comb with a film thickness of 0.05 μm and 1 μm, respectively, as the upper electrode, and the photoconductivity and dark conductivity were examined as basic characteristics of the semiconductor layer. As a result, in each survey item, the maximum difference between the sample at the edge of the substrate and the sample at the center of the substrate was within 2.5%, and was within 3% between samples.

[Comparative Example 1]
For comparison, a comparative experiment was performed in the same manner as in Example 1 except that the preheating temperature was 200 ° C. and the substrate was carried into the processing chamber while the deflection amount at the center of the substrate was 2 mm. As a result of examining the same investigation items as in Example 1, the maximum difference between the sample at the substrate end and the sample at the center of the substrate was 11%, and 5% between the samples.

[Example 2]
Using the continuous plasma CVD apparatus shown in FIG. 3, solar cells as shown in FIG. 2 were continuously produced. Hereinafter, it demonstrates according to a procedure.

The substrate delivery chamber 302 is sufficiently degreased and cleaned, and as a lower electrode, a SUS430BA strip-shaped substrate 301 (width 300 mm × length 900 m × thickness 0) is deposited by sputtering as an Al thin film with a thickness of 100 nm and a ZnO thin film 1 μm. .2 mm) wound bobbin 308 is set, and the belt-like substrate 301 is formed into an n-type semiconductor layer deposition container 304, an i-type semiconductor layer deposition container 305, an H ₂ plasma processing container 306, a p-type semiconductor layer formation. The film container 307 was passed through the gas gate 315 to the substrate take-up chamber 303, and the tension was adjusted to such an extent that there was no slack.

Each container 302, 303, 304, 305, 306, 307 was evacuated to 1.33 × 10 ⁻¹ Pa or less by a vacuum pump (not shown).

(Heat treatment before film formation)
As a gate gas, H ₂ is supplied to the gas gate 315 through the gate gas introduction pipe 316 at 500 atm · cc / min, and He is supplied to the film forming containers 302, 303, 304, 305, 306, 307 from the gas introduction pipe (not shown) at 500 atm · cc, respectively. / Min, the opening of the throttle valve 313 is adjusted so that the internal pressure of each film formation container becomes 133 Pa, and each film formation container is evacuated by a vacuum pump (not shown) through the exhaust pipe 312. Thereafter, the band-shaped substrate 301 and the wall surface of the processing chamber 321 were heated to 400 ° C. by the infrared lamp heater 319 and the processing chamber heater 322, and left in this state for 4 hours.

  Then, each container 302,303,304,305,306,307 was evacuated with the vacuum pump (not shown) to 1.33 Pa or less.

(Gate gas introduction during film formation)
H ₂ is introduced into each gas gate 315 as a gate gas from the gate gas introduction pipe 316 by 1000 atm · cc / min.

(Preparation of n-type semiconductor layer deposition)
A substrate deformation heating temperature control device (not shown) is set so that the temperature indication value of the substrate deformation monitor thermocouple 325 is 250 ° C., and the belt-shaped substrate 301 is heated by the heater unit 326. A temperature control device (not shown) is set so that the temperature indication value of the thermocouple 317 is 270 ° C., and the strip substrate 301 is heated by the infrared lamp heater 319. SiH ₄ gas is introduced at 50 atm · cc / min, PH ₃ / H ₂ (1%) gas at 300 atm · cc / min, and H ₂ gas is introduced at 1200 atm · cc / min from the gas introduction pipe 323. The opening degree of the throttle valve 313 was adjusted so that the pressure in the processing chamber 321 of the n-type semiconductor layer deposition container 304 was 100 Pa, and the exhaust was exhausted through an exhaust pipe 312 by a vacuum pump (not shown). The output value of the RF power source 314 is set to 100 W, and discharge is generated in the processing chamber 321 through the electrode 318.

(Preparation for i-type semiconductor layer deposition)
Similarly to the preparation for forming the n-type semiconductor layer, the temperature is set so that the belt-like substrate temperature becomes 360 ° C. From the gas introduction pipe 323, SiH ₄ gas is introduced at 500 atm · cc / min, GeF ₄ gas is introduced at 500 atm · cc / min, and H ₂ gas is introduced at 8000 atm · cc / min. The opening of the throttle valve 313 was adjusted so that the pressure in the processing chamber 321 of the i-type semiconductor layer deposition container 305 was 300 Pa, and the exhaust was exhausted through an exhaust pipe 312 with a vacuum pump (not shown). The output value of the RF power source 314 is set to 5000 W, and discharge is generated in the processing chamber 321 through the electrode 318.

(Preparation for p-type semiconductor layer deposition)
Similar to the preparation for the n-type semiconductor layer film formation and the i-type semiconductor layer film formation, the band-shaped substrate temperature is set to 250 ° C. SiH ₄ gas is introduced at 10 atm · cc / min, B ₂ H ₆ / H ₂ (1% diluted) gas is introduced at 1000 atm · cc / min, and H ₂ gas is introduced at 6000 atm · cc / min from the gas introduction pipe 323. The opening of the throttle valve 313 was adjusted so that the pressure in the processing chamber 321 of the p-type semiconductor layer deposition container 307 was 50 Pa, and the exhaust was exhausted through an exhaust pipe 312 with a vacuum pump (not shown). The output value of the RF power source 314 is set to 3000 W, and discharge is generated in the processing chamber 321 through the electrode 318.

(Preparation for H ₂ plasma treatment)
A substrate deformation heating temperature control device (not shown) is set so that the temperature indication value of the substrate deformation monitor thermocouple 325 becomes 120 ° C., and the belt-shaped substrate 301 is heated by the heater unit 326. A temperature control device (not shown) is set so that the temperature indication value of the thermocouple 317 is 120 ° C., and the strip substrate 301 is heated by the infrared lamp heater 319. H ₂ gas is introduced at 1000 atm · cc / min from the gas introduction pipe 323. The opening degree of the throttle valve 313 was adjusted so that the pressure in the processing chamber 321 of the H ₂ plasma processing container 306 was 665 Pa, and the exhaust gas was exhausted through an exhaust pipe 312 by a vacuum pump (not shown). The output value of the RF power source 314 is set to 3000 W, and discharge is caused in the processing chamber 321 through the electrode 318.

  Next, when the belt-like substrate 301 is conveyed at a speed of 2000 mm / min in the direction of arrow B in the figure, the maximum deflection amount at the farthest processing chamber is obtained by the substrate displacement sensor 324 of the n-type semiconductor layer deposition container 304. Since about 1 to 3 mm was monitored at the center of the substrate, the heater unit 326 was controlled in power so that the amount of deflection in the vicinity of the processing chamber was 0.5 mm or less, and the band-shaped substrate 301 was processed for forming an n-type semiconductor layer. It was made possible to carry it into the room continuously. The display value of the substrate deformation monitor thermocouple 325 monitored at that time was in the range of 230 to 300 ° C.

  Similarly, since the maximum deflection amount at the farthest processing chamber is monitored by the substrate displacement sensor 324 of the i-type semiconductor layer deposition container 305 at about 2 to 5 mm at the center of the substrate, the deflection amount near the processing chamber is 1 The electric power of the heater unit 326 was controlled so that the thickness was 0.0 mm or less so that the belt-like substrate 301 could be continuously carried into the i-type semiconductor layer deposition processing chamber. The display value of the substrate deformation monitor thermocouple 325 monitored at that time was in the range of 300 to 400 ° C.

  Similarly, since the maximum deflection amount at the farthest processing chamber is monitored by the substrate displacement sensor 324 of the p-type semiconductor layer deposition container 307 at about 2 to 4 mm at the center of the substrate, the deflection amount near the processing chamber is 2 The electric power of the heater unit 326 was controlled so that the thickness was 0.0 mm or less, so that the belt-like substrate 301 could be continuously carried into the p-type semiconductor layer deposition processing chamber. The display value of the substrate deformation monitor thermocouple 325 monitored at that time was in the range of 100 to 200 ° C.

Similarly, since the maximum deflection amount at the farthest processing chamber is monitored by the substrate displacement sensor 324 of the H ₂ plasma processing container 306 about 1 to 4 mm at the center of the substrate, the deflection at the closest proximity to the processing chamber is 3.0 mm. The power of the heater unit 326 was controlled so as to be as follows so that the belt-like substrate 301 could be continuously carried into the H ₂ plasma processing chamber. The display value of the substrate deformation monitor thermocouple 325 monitored at that time was in the range of 100 to 130 ° C.

In accordance with the above, an n-type semiconductor layer film formation process, an i-type semiconductor layer film formation process, an H ₂ plasma process, and a p-type semiconductor layer film formation process were successively performed. These processing conditions are summarized in Table 1.

After one roll of the strip substrate was transported, all plasma, all gas supply, all lamp heater energization, and transport of the strip substrate were stopped. Next, after purging each film forming gas line with He gas, N ₂ gas for film forming container leakage is introduced into each processing container (the introduction member is not shown), and each processing container is sufficiently cooled at 1000 Pa. Then, it was returned to atmospheric pressure, and the belt-like substrate wound around the winding bobbin was taken out.

Next, ITO (In ₂ O ₃ + SnO ₂ ) is deposited as a transparent electrode by 150 nm on the p-type semiconductor layer of the band-shaped substrate by vacuum deposition, and Al is further deposited as a collecting electrode by 3 μm by vacuum deposition. A solar cell (sample No. 2) shown in FIG.

[Comparative Example 2]
In this example, Example 2 is performed except that the substrate is heated to the same temperature as the substrate processing temperature in the conventional processing chamber immediately before being carried into the processing chamber without correcting the deflection of the substrate in each processing container. In the same manner as above, a solar cell (Comparative Sample No. 2) was produced on a roll substrate of 1 roll.

  Within one roll, sample no. 2, comparative sample No. Samples were cut out every 100 m in each of No. 2 and Sample No. 2-1, 2-2, 2-3, 2-4, 2-5, 2-6, 2-7, and 2-8. 2-1, 2-2, 2-3, 2-4, 2-5, 2-6, 2-7 and 2-8.

First, for each of the solar cell obtained in Example 2 (Sample No. 2) and the solar cell obtained in Comparative Example 2 (Comparative Sample No. 2), photoelectric conversion efficiency η = {maximum generated power per unit area (MW / cm ² ) / incident light intensity per unit area (mW / cm ² )} was evaluated.

Sample No. 2 of Example 2 2 and Comparative Sample No. 2 of Comparative Example 2 2 is placed under AM-1.5 (100 mW / cm ² ) light irradiation, DC voltage is applied to the extraction electrode 209 in FIG. 2, current-voltage characteristics are measured, open voltage, fill factor and photoelectric When the conversion efficiency η was evaluated, the sample No. 2-1 and comparative sample No. 2-1, Comparative Sample No. Sample no. The solar cell of 2-1 was excellent in that the open circuit voltage value was 1.09 times, the fill factor value was 1.15 times, and the photoelectric conversion efficiency η averaged 1.22 times. Sample No. The average value of the characteristic values of 2-2 to 7 and the comparative sample No. When the average values of the characteristic values of 2-2 to 7 were compared, Sample No. The 2-2-7 solar cells were superior in that the open circuit voltage value was 1.11 times, the fill factor value was 1.20 times, and the photoelectric conversion efficiency η averaged 1.23 times. In addition, the comparative sample No. In 2-8, the characteristics as a cell were hardly exhibited.

  Moreover, each of the solar cell (sample No. 2-1) produced in Example 2 and the solar cell (comparative sample No. 2-1) produced in Comparative Example 2 is a protective film made of polyvinylidene fluoride (VDF). After vacuum sealing and placing in actual use conditions (installed outdoors, 50 ohm fixed resistor connected to both electrodes) for 1 year, photoelectric conversion efficiency was evaluated again, deterioration rate due to light irradiation (deterioration) Obtained by dividing the value of the photoelectric conversion efficiency impaired by the initial photoelectric conversion efficiency). As a result, the deterioration rate of the solar cell (sample No. 2-1) in which the semiconductor layer is formed according to the present invention is relative to the deterioration rate of the solar cell (comparative sample No. 2-1) in which the semiconductor layer is formed by the conventional method. The ratio was as low as 15%.

  From the above, it was found that the solar cell produced according to the present invention has dramatically improved photoelectric conversion efficiency and greatly improved reliability under actual use conditions.

Example 3
In this example, in place of the example 2 provided with one set of pin junctions on the surface of the lower electrode, three sets of pin junctions were stacked and used. Thus, when three sets of pin junctions are stacked, it is called a triple solar cell. Here, the other points where the H ₂ plasma treatment is not performed on the light incident side pin junction are the same as those in the second embodiment.

In the case of manufacturing the triple solar cell, a new n-type semiconductor layer deposition container, i, is newly provided between the p-type semiconductor layer deposition container 307 and the winding container 303 of the continuous plasma CVD apparatus shown in FIG. Type semiconductor layer film formation container, H ₂ plasma processing container, p type semiconductor layer film formation container, n type semiconductor layer film formation container, i type semiconductor layer film formation container, p type semiconductor layer film formation container via each gas gate Connected and expanded.

  The first and second pin junctions are a-SiGe: H, and the third pin junction is a-Si: H to form an i-type semiconductor layer. These processing conditions are summarized in Table 2. The stacking order is the order from the upper column to the lower column in Table 2.

Then, using the continuous modularization apparatus (not shown), the produced solar cell was processed into a large number of solar cell modules having a size of 36 cm × 22 cm. When the characteristics of the processed solar cell module were evaluated using pseudo-sunlight with an energy density of 100 mW / cm ² at AM 1.5, a photoelectric conversion efficiency of 13.5% or more was obtained, and each solar cell module The variation in the characteristics was within 5%. In addition, two of the processed solar cell modules were extracted and subjected to repeated bending tests for 300 times. As a result, the characteristics did not deteriorate even after the test, and no phenomenon such as peeling of the deposited film was observed. It was. Furthermore, even after irradiating pseudo-sunlight having an energy density of 100 mW / cm ² with the above AM1.5 for 1000 hours, the photoelectric conversion efficiency was within 7.5% of the initial value. By connecting this solar cell module, a power supply system with an output of 3.5 kW could be configured.

Example 4
In this example, ZnO for the reflection enhancement layer was formed on a 50 cm square SUS substrate by sputtering using the vacuum processing apparatus of the present invention shown in FIG. Note that Ar was used as the sputtering gas, and a ZnO target was used as the target.

  4 mainly includes an outer container 402, a processing chamber 403, a gas manifold 404, a target 405, an exhaust passage 407, an O-ring 408, a heater unit 409 for controlling the amount of deflection of the substrate, and a substrate. Displacement sensor 410, DC power supply 411, substrate transport unit 412, substrate holder 413 for holding substrate 401, processing gas introduction valve 414, magnet 415, substrate heating heater unit 416, shutter 417, substrate temperature control thermocouple 418, It comprises a processing chamber wall temperature control thermocouple 419 and a substrate displacement sensor transmission window 420.

  The substrate displacement sensor 410 detects the amount of deflection of the substrate 401 before being carried into the processing chamber 403. The heater unit 409 includes a large number of heaters arranged in a plane, and supplies power by selecting an arbitrary region based on the substrate deflection amount (deflection amount distribution) detected by the substrate displacement sensor 410. It is configured to be able to.

  First, with respect to the substrate, in order to improve the operation rate of the apparatus, preheating was performed in advance before carrying in the processing chamber. As for the heating method, electric power was supplied to the heater unit 409 while confirming the deflection amount of the substrate by the substrate displacement sensor 410, and the temperature was adjusted to 150 ° C. which is the optimum temperature for film deposition in the processing chamber. At that time, since the deflection amount of the substrate at the central portion of the substrate was 5 mm, electric power was supplied only to the outer peripheral portion of the heater unit 409 so that only the peripheral portion of the substrate was 180 ° C. As a result, the amount of deflection of the substrate was 3 mm or less.

  After that, the substrate was introduced into the processing chamber 403, the pressure was set to 10 Pa, and DC power was applied from the DC power source 411 to the ZnO target 405 as an electrode to cause discharge. After the discharge was stabilized, the shutter 417 was opened, and a ZnO film was deposited on the 50 cm square SUS substrate by 2.5 μm. After deposition, the shutter 417 was closed and the substrate was replaced. The film deposition time required per trial was 30 minutes.

  This trial was repeated 300 times, and 20 samples extracted arbitrarily were divided into 9 pieces at the center and end of the substrate, respectively, and the basic characteristics of the film thickness and the reflection increasing film layer were reflectivity and sheet. The resistance was examined. As a result, in each investigation item, the maximum difference from the samples on the center and end sides of the substrate was within 3%, and was within 1% between samples.

[Comparative Example 3]
For comparison, a ZnO film is deposited on the SUS substrate in the same manner as in Example 4 except that the preheating temperature is 150 ° C. and the substrate is carried into the processing chamber while the deflection at the center of the substrate is 5 mm. A comparative experiment was conducted. As a result of examining the same investigation items as in Example 4, the maximum difference between the sample at the substrate end and the sample at the center of the substrate was 12%, and 4% between samples.

Example 5
A microcrystal silicon semiconductor film was formed on a 50 cm square SUS substrate using the vacuum processing apparatus shown in FIG.

  Regarding the substrate, in order to improve the operation rate of the apparatus, preheating was performed in advance before the processing chamber was carried in. As the heating method, electric power was supplied to the heater unit 109 while confirming the amount of deflection of the substrate by the substrate displacement sensor 110, and the temperature was adjusted to 300 ° C., which is the optimum temperature for film deposition in the processing chamber. At that time, since the deflection amount of the substrate at the central portion of the substrate was 6 mm, electric power was supplied only to the outer peripheral portion of the heater unit 109 so that only the peripheral portion of the substrate was 250 ° C. As a result, the amount of deflection of the substrate was 4 mm or less.

Thereafter, the substrate was introduced into the processing chamber 103, and the distance between the electrode 105 and the substrate was set to 5 mm. SiH ₄ and H ₂ were used as the deposition film forming source gas. The pressure was set to 300 Pa, and high frequency power 8000 W was applied to the electrode 105 from the high frequency power source (80 MHz) 111 to cause discharge. After the discharge was stabilized, the shutter 117 was opened, and 2 μm of a microcrystal silicon film was deposited on the 50 cm square SUS substrate. After deposition, the shutter 117 was closed and the substrate was replaced. The deposited film formation time required per trial was 200 minutes.

  This trial was repeated 100 times in succession, and the five samples arbitrarily extracted were divided into a total of three, two on the processing gas introduction side and one on the center side, and the film thickness was examined. Moreover, Cr / Ag was vapor-deposited in the shape of a comb with a film thickness of 0.05 μm and 1 μm, respectively, as the upper electrode, and the photoconductivity and dark conductivity were examined as basic characteristics of the semiconductor layer. As a result, in each survey item, the maximum difference between the sample on the processing gas inlet side and the sample on the central side was within 3%, and was within 4% among samples with different trial numbers. .

It is a schematic diagram for demonstrating the plasma CVD apparatus which is an example of the substrate processing apparatus of this invention. It is a schematic diagram which shows one structural example of the solar cell which can use this invention suitably. It is a schematic diagram for demonstrating the continuous plasma CVD apparatus which is an example of the substrate processing apparatus of this invention. It is a schematic diagram of the reflection increasing film manufacturing apparatus which concerns on Example 4 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Vacuum processing apparatus 101 Substrate 102 External container 103 Processing chamber 104 Gas manifold 105 Electrode 106 Gas introduction port 107 Exhaust flow path 108 O-ring 109 Heater unit 110 for controlling the deflection amount of a substrate 110 Substrate displacement sensor 111 High frequency power supply 112 Substrate conveyance Unit 113 Substrate holder 114 Processing gas introduction valve 115 Heater for processing chamber wall 116 Heating unit for substrate 117 Shutter 118 Thermocouple for controlling substrate temperature 119 Thermocouple for controlling temperature of processing chamber 120 Transmission window 201 Solar cell 202 Conductivity Substrate 203 Lower electrode 204 n-type semiconductor layer 205 i-type semiconductor layer 206 p-type semiconductor layer 207 Transparent electrode 208 Current collecting electrode 209 Extraction electrode 300 Continuous plasma CVD apparatus 301 Strip substrate 302 Delivery container 303 Winding Container 304 n-type semiconductor layer deposition container 305 i-type semiconductor layer deposition container 306 H ₂ plasma processing container 307 p-type semiconductor layer deposition container 308 delivery bobbin 309 take-up bobbin 310, 311 transport roller 312 exhaust pipe 313 Throttle valve 314 High frequency power supply 315 Gas gate 316 Gate gas introduction tube 317 Thermocouple 318 Electrode 319 Infrared lamp heater 320 Lamp house 321 Processing chamber 322 Processing chamber heater 323 Gas introduction tube 324 Substrate displacement sensor 325 Substrate deformation monitor thermocouple 326 Heater unit 400 Vacuum processing apparatus 401 Substrate 402 External container 403 Processing chamber 404 Gas manifold 405 Electrode (target)
406 Gas introduction port 407 Exhaust flow path 408 O-ring 409 Heater unit 410 for controlling substrate deflection amount Substrate displacement sensor 411 DC power supply 412 Substrate transport unit 413 Substrate holder 414 Processing gas introduction valve 415 Magnet 416 Heater for substrate heating 417 Shutter 418 Thermocouple 419 for substrate temperature control Thermocouple 420 for process chamber wall temperature control Transmission window

Claims (13)

  In a substrate processing method for processing a substrate surface by loading a substrate into the processing space, the substrate is placed in the processing space after controlling the amount of bending of the substrate based on the amount of bending of the substrate carried into the processing space. A substrate processing method comprising carrying-in.   The substrate processing method according to claim 1, wherein the substrate surface is processed by a plasma CVD method.   The substrate surface treatment is a method of treating a substrate by applying electric power to an electrode disposed opposite to the substrate, wherein a distance between the electrode and the substrate is in a range of 1 mm to 70 mm. The substrate processing method of Claim 1 or 2.   2. The substrate processing method according to claim 1, wherein the substrate surface is processed by a sputtering method.   5. The substrate processing method according to claim 1, wherein the means for controlling the amount of deflection of the substrate uses a heat source.   6. The substrate processing method according to claim 1, wherein a deflection amount of the substrate is detected by a sensor, and the deflection amount of the substrate is controlled based on the detected deflection amount.   Predicting the relationship between the amount of deflection of the substrate in the processing space and the processing time, controlling the amount of deflection of the substrate based on the predicted amount of deflection of the substrate, and then loading the substrate into the processing space. The substrate processing method according to claim 1, wherein:   The vacuum processing method according to claim 1, wherein the substrate is a strip-like long substrate.   9. The vacuum processing method according to claim 1, wherein a deflection amount of the substrate is controlled in a range of 0.5 mm to 4.0 mm.   In a substrate processing apparatus that carries a substrate into a processing space and processes the substrate surface, the substrate processing apparatus has means for detecting the amount of deflection of the substrate carried into the processing space, and means for controlling the amount of deflection of the substrate. A substrate processing apparatus.   11. The substrate processing apparatus according to claim 10, further comprising means for disposing an electrode facing the substrate in the processing space, wherein a distance between the electrode and the substrate is in a range of 1 mm to 70 mm. .   12. The substrate processing apparatus according to claim 10, wherein the means for controlling the deflection amount of the substrate uses a heat source.   13. The substrate processing apparatus according to claim 10, further comprising means for storing the detected deflection amount of the substrate.

Images