JPH11229193A - Electrodepositon device of long-sized substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrodeposition device of a long-sized substrate by which a uniform oxide film without generating irregularity of wave-shaped and striped patterns is electrodeposited uniformly on the long-sized substrate. SOLUTION: This electrodeposition device of a long-sized substrate is provided with an electrodeposition tank for applying a current between a long-sized substrate 1001 and an electrode in an electrodeposition bath 1016 to form an oxide film on the substrate 1001, a washing means for washing the substrate 1001 passed through the tank with water and a drying means for forcedly drying the passed substrate 1001. Then, the device has a conveying speed in which a time required for a bath soln. brought out on the substrate surface from the bath 1016 to be naturally dried and to deposit the solute in a conveyor line between the tanks is shorter than a time required for the substrate to pass between the tanks by a substrate conveying means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to an electrodeposition method (electroplating method and electrolytic deposition method) on a long substrate such as a stainless steel strip.
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrodeposition apparatus for forming an oxide film by using the method, and particularly to an electrodeposition apparatus for forming a zinc oxide film uniformly on a long substrate.

[0002]

2. Description of the Related Art In recent years, in the production of photovoltaic devices,
A technique of forming an oxide on a substrate by using an electrochemical reaction of an aqueous solution instead of a vacuum process has attracted attention.
For example, Japanese Patent Application Laid-Open No. 09-092661 proposes an invention relating to "a method for manufacturing a photovoltaic element".
A "method of forming an oxide such as zinc oxide on a long substrate by an electrodeposition method and an apparatus used for the method" is disclosed.

FIG. 2 is a schematic view showing an example of an apparatus for producing an oxide by an electrodeposition method based on the publication, which is simplified to a function of merely forming a zinc oxide film by an electrodeposition method. It is.

In FIG. 2, reference numeral 2001 denotes a long substrate such as a stainless steel strip wound in a roll shape, which is called a hoop material, a roll substrate or a web. Long board 2
001 is transported to the apparatus as a cylindrical substrate wound in a coil shape on a bobbin.

In this apparatus, a coil-shaped long substrate 2001 is used.
Is placed on the substrate unwinding roller 2002, and while the unwinding sheet inserted for protecting the surface is unwound by the unwinding unwinding roller 2003, the unwound substrate is conveyed to the substrate unwinding roller 2062 and wound. .

That is, the substrate 2001 enters the electrodeposition tank 2009 via the tension detection roller 2005 and the power supply roller 2006 in the transport path. Electrodeposition tank 20
09, the substrate 2001 is supported by the support rollers 201.
3, 2014, and an oxide film is formed by an electrodeposition method.

Next, the substrate 20 having passed through the electrodeposition tank 2009
01 is introduced into the washing tank 2030 and washed. Positioning inside the washing tank 2030 is performed by the support roller 20.
31, 2066. The substrate 2001 that has passed through the washing tank 2030 is introduced into a hot-air drying furnace 2051 and dried.

The substrate 200 that has passed through the hot air drying oven 2051
1 includes a support roller 2057, a meandering correction roller 2059 that corrects the lateral displacement, and a new interleaf fed from the interleaf feed roller 2060 to protect the film-forming surface.
And transported to the next step as needed.

[0009] The tension detecting roller 2005
The dynamic winding tension of No. 1 is detected, and feedback is applied to a braking means such as a powder clutch (not shown) linked to the axis of the substrate feeding roller 2002 to keep the tension constant. Thereby, the transfer path of the substrate 2001 is designed to have a predetermined value between the support rollers.

[0010] In particular, in this apparatus, since the roller does not come into contact with the film-forming surface, if the tension is weak, the substrate 2001 may come off from the support roller, or the substrate may enter or leave the electrodeposition tank 2009 or the washing tank 2030. Inconveniences such as that the film 2001 hangs down and rubs the film-formed surface to cause damage.

An apparatus configuration in which the film formation surface does not touch has the advantage that the film formation surface is not damaged or contaminated. In particular, micron-sized unevenness such as a reflective film of a solar cell is formed on the thin film. Preferred for applications that must be formed.

The power supply roller 2006 is for applying a potential on the cathode side to the long substrate, is installed as close as possible to the electrodeposition bath, and is connected to the negative electrode side of the power supply 2008.

The electrodeposition tank 2009 holds the electrodeposition bath 2016, determines the path of the substrate 2001, installs the anode 2017 on the path, and supplies the anode 2017 with the positive electrode from the power source 2008 via the power supply bar 2015. Apply potential. Thereby, an electrochemical electrolytic deposition process in which the substrate 2001 is negative and the anode 2017 is positive in the electrodeposition bath proceeds.

When the electrodeposition bath 2016 is kept at a high temperature,
Since the generation of steam becomes considerably large, the steam discharge duct 2
Water vapor is released from 010, 2011, 2012.

In order to stir the electrodeposition bath 2016,
Air is introduced from the stirring air introduction pipe 2019, and air is bubbled from the air blowing pipe 2018 in the prayer tank 2009.

To replenish the electrodeposition tank 2009 with a high-temperature bath solution, an electrodeposition circulation tank 2025 is provided, in which a heater 20 is provided.
The bath is heated by installing 24, and the bath solution is supplied from the bath circulation pump 2023 to the electrodeposition tank via the electrodeposition bath solution supply pipe 2020. The bath solution overflowing from the electrodeposition tank 2009 or the bath liquid to be partially positively returned is returned to the electrodeposition circulation tank 2025 via a return path (not shown) and heated again.

When the discharge rate of the pump is constant, the amount of bath supply from the electrodeposition circulation tank 2025 to the electrodeposition tank 2009 can be controlled by the valves 2021 and 2022. That is, when increasing the supply amount, the valve 2021
Are opened and the valve 2022 is closed more. When the supply amount is reduced, the reverse operation is performed. The level of the retained water in the electrodeposition bath 2016 is adjusted by adjusting the supply amount and the return amount (not shown).

The electrodeposition circulation tank 2025 has a circulation pump 20
A filter circulating system including a filter 27 and a filter is provided to remove particles in the electrodeposition circulating tank 2025. Electrodeposition circulation tank 2025 and electrodeposition tank 2009
When the supply / return of the bath liquid between these steps is sufficiently large, a sufficient particle removing effect can be obtained by providing a filter only in the electrodeposition circulation tank 2025 in this manner.

In the present apparatus, a vapor discharge duct 2026 is also provided in the electrodeposition circulation tank 2025, so that the vapor is discharged. In addition, since the heater 2024 is installed in the electrodeposition circulation tank 2025 and serves as a heating source, the generation of steam is remarkable, and it is not preferable that the generated steam is released carelessly or dewed. The case is extremely effective.

The electrodeposition preparatory tank 2029 is provided to prevent the heated bath liquid from flowing into the existing waste liquid system at a stretch to damage the processing apparatus, and once the electrodeposition bath 2016 in the electrodeposition tank 2009 is used. This is for keeping the work and emptying the electrodeposition tank 2009 to improve the work efficiency.

The substrate 200 which has been electrodeposited in the electrodeposition tank 2009
1 then enters a washing tank 2030 and is washed with water. In the washing tank 2009, the substrate 2001 is
1 and the supporting roller 2066, and sequentially pass through the first washing tank 2032, the second washing tank 2033, and the third washing tank 2034.

The washing circulation tanks 2047 to 2049 are provided respectively.
And water circulation pumps 2044 to 2046, and two valves, that is, valve 2038 and valve 2041, or valve 2039 and valve 2042, or valve 2
040 and the valve 2043 determine the amount of water to be supplied to the washing tank 2009, and the supply pipe 2035 or the supply pipe 203
6, or through the supply pipe 2037, the washing tank 2032
Cleaning water is supplied into 2034.

The control method of the supply amount by the two valves is the same as the control in the electrodeposition tank 2009. In addition, electrodeposition tank 200
As in the case of No. 9, return water (not shown) that collects overflow or actively returns a part is supplied to each of the washing circulation tanks 2047.
It is also possible to return to ２０４2049.

Normally, in a three-stage washing system as shown in FIG. 2, an upstream washing tank in the substrate transport direction and a downstream washing tank, that is, a first washing tank 2032 to a third washing tank 20 are used.
Towards 34, the purity of the wash water has increased. This means that the cleanliness of the substrate 2001 increases as the substrate 2001 is conveyed and the process approaches the end.

This means that the washing water is supplied to the third washing circulation tank 20.
First, the washing water overflowing in the third washing circulation tank 2049 is supplemented to the second washing circulation tank 2048, and the washing water overflowing in the second line-of-sight circulation tank 2048 is further washed with the first washing circulation tank 2047. By replenishing the water, the amount of water used can be significantly reduced.

The substrate 2001 having been rinsed is placed in a rinse tank 2.
030 is drained by an air knife 2065 provided in a part of 030, and subsequently conveyed to a hot air drying furnace 2051.
Here, drying is performed with convective air at a temperature sufficient to dry the water sufficiently. The convection air supplies hot air generated in the hot air generating furnace 2055 by removing dust through a filter 2054 and blowing out the hot air from a hot air blowing pipe 2052.

The overflowing air is collected again from the hot air collection pipe 2053, mixed with the outside air from the outside air introduction pipe 2056, and sent to the hot air generation furnace.

The transport path of the substrate 2001 in the hot air drying oven is positioned by the support roller 2066 and the support roller 2057.

The meandering correction roller 2059 is connected to the substrate 200
1 to correct the widthwise deviation of the substrate winding roller 20
The sensor is controlled by rotating the meandering correction roller 2059 around an arm (not shown) as a fulcrum. Normally, the deviation detected by the sensor is also the meandering correction roller 2.
The working amount of 059 is also extremely small so as not to exceed 1 mm.

When winding up the substrate 2001, a new slip sheet is supplied from a slip sheet feeding roller 2060 to protect the surface film.

The stopper 2007 and the stopper 2058
Work simultaneously to stop the substrate 2001 while the transfer tension is applied. This improves workability at the time of replacement of the board 2001 or maintenance of the apparatus.

The use of the electrodeposition apparatus shown in FIG. 2 has the following advantages.

First, unlike a vacuum apparatus such as a sputtering apparatus, film formation is extremely simple. There is no need for expensive vacuum pumps, and there is no need to worry about the power supply for using plasma or the design around the electrodes.

Second, running costs are low in most cases. This is a sputtering device, which requires manpower and equipment to produce the target, which is expensive,
This is because the target utilization efficiency is about 20% or less. Therefore, when the throughput of the apparatus is increased or the film thickness is large, the work of replacing the target occupies a considerable weight.

In addition to sputtering, CVD and vacuum evaporation are also superior in terms of equipment and running cost.

In many cases, the film is composed of polycrystalline fine particles, and exhibits conductive and optical properties comparable to those produced by a vacuum method. It is also possible to use a sol-gel method, a coating method using an organic substance, and a spray pyrolysis method. It has an advantage over law.

Further, even when an oxide is formed, the above holds true, the waste liquid can be easily treated, the influence on the environment is small, and the cost for preventing environmental pollution is low.

[0038]

However, when a film is formed by the above-mentioned electrodeposition apparatus, the following disadvantages have been found.

That is, although the electrodeposition in the electrodeposition bath 2009 is performed very successfully, the solute concentration of the electrodeposition bath 2016 is high and the bath temperature is high. As a result, unevenness of a wavy stripe pattern is generated on the film-formed surface after drying. For example, in order to form a solar cell, the unevenness of the wavy stripe pattern does not disappear even when a semiconductor electromotive layer mainly composed of amorphous silicon and a transparent conductive layer such as ITO are formed by a CVD method. Has a problem that it becomes clearer and remains as unevenness of characteristics.

According to the present invention, a uniform oxide film free from unevenness of wavy stripes can be uniformly deposited on a long substrate, and an oxide film suitable for a reflective layer of a solar cell is formed. It is an object of the present invention to provide an apparatus for electrodeposition of a long substrate that can be used.

[0041]

In order to achieve the above object, the present invention provides an electrodeposition bath for forming an oxide film on a substrate by energizing a long substrate and an electrode in an electrodeposition bath. A long substrate electrodeposition apparatus, comprising: a washing means for washing the substrate passed through the electrodeposition bath, and a drying means for forcibly drying the substrate passed through the water washing means, wherein the transport means for the long substrate is provided. Has a transfer speed that passes between the tanks in a shorter time than the time required for the bath liquid taken out from the electrodeposition bath to the substrate surface to naturally dry and precipitate solute on the transfer path between the tanks. . If a long substrate is conveyed at such a conveying speed, the bath liquid taken out of the electrodeposition tank to the substrate surface is conveyed to a washing tank or the like before the natural drying, so that no solute is deposited and a wavy stripe pattern is formed. Does not occur.

In order to uniformly form an oxide film, the electrodeposition bath preferably contains a saccharide.

The temperature of the electrodeposition bath is preferably 60 ° C. or higher so that no metal is deposited in the electrodeposition bath.

In particular, when the temperature of the electrodeposition bath is 80 ° C. or higher, a film can be stably formed by an electrodeposition process requiring a high temperature such as zinc oxide.

Further, since a plurality of electrodeposition tanks are provided in the substrate transfer path, even if the transfer speed of the substrate is increased, it is easy to deposit zinc oxide having a sufficiently large thickness. It can be carried out.

At least in the transport path on the outlet side of the electrodeposition tank, there is provided a liquid spraying means for spraying the liquid onto the substrate passing through the electrodeposition tank and preventing the bath liquid taken out on the surface from drying. As a result, the solute in the bath solution taken out of the electrodeposition tank can be effectively diluted or discharged.

As the dispersion, water, the same bath as the preceding electrodeposition bath, or a mixture of the same and water is suitable.

A plurality of washing tanks are provided as washing means,
If the temperature of the washing water is high enough to make the substrate surface easy to dry in the transport path, humidifying means for providing moisture to the substrate surface is provided between the washing tanks. By this humidifying means, since the occurrence of uneven wavy stripes on the film formation surface is prevented, even when the electrodeposition bath contains saccharides such as sucrose,
The washing effect can be enhanced by keeping the temperature of the washing water high.

By using a roller in contact with the surface of the substrate as the transfer means, the transfer direction of the substrate need not necessarily be limited to a horizontal direction, and the degree of freedom in designing the entire electrodeposition apparatus is greatly improved.

When the substrate is made of a ferromagnetic material, by using a magnet roller in contact with the upper surface of the substrate as a transporting means, it is possible to avoid vertical movement at the overflow portion and to prevent the occurrence of unevenness due to overflow or droplets. be able to.

Further, since the oxide formed in the electrodeposition bath is zinc oxide, the solvent of the bath solution is water, and the solute precipitated by drying is zinc nitrate, extremely stable zinc oxide is obtained. Can be formed by electrodeposition.

Next, the structure and operation of the present invention will be further described, together with the circumstances that led to the present invention. That is, the present inventors studied the unevenness of the wavy stripe pattern by the following experiment.

FIG. 1 is an enlarged schematic view showing the vicinity of the connection between the electrodeposition tank and the washing tank. In FIG. 1, the electrodeposition bath 1016
Is held by the electrodeposition tank wall 1067, but there is an opening for partially passing the substrate 1001.
1 is conveyed to the outside of the folding tank 2009 from this opening. Naturally, a part of the bath liquid overflows from this opening.
3, which is collected and collected by the electro-circulation tank 20.
Return to 25.

Since the upper surface of the substrate 1001 (the surface on which the film is not formed) is not greatly affected even if it is rubbed,
5, the substrate 1001 is positioned by the support roller 1014 so as to be aligned with the blade.

Further, an overflow cover 1068 is provided in order to suppress the liquid splash from overflowing.

The entrance to the washing tank 2030 is connected to the electric folding tank 200
It has a symmetrical structure with the outlet 9 and the function is also symmetrical. That is, the washing tank 2030 has a configuration symmetrical to the electric folding tank 2009, and includes the washing tank wall 1070, the overflow cover 1069, the liquid draining blade 1066, and the support roller 1031.

Although a considerable amount of overflows 1063 and 1064 can be seen from the electrodeposition tank 2009 and the washing tank 2030, the bath circulation pump 2023 and the water circulation pump 2044-
If the circulation amount of 2046 is sufficiently large with a capacity of 100 to 200 l / min, the liquid level of the electrodeposition bath and water is adjusted to the substrate 1.
It is easy to keep it a few cm above 001.

In the apparatus used for the experiment, the electrodeposition tank wall 10
The distance between 67 and overflow cover 1068 is 150m
m, the distance between the overflow cover 1068 and the overflow cover 1069 is 200 mm, and the overflow cover 1
The distance between 069 and the washing tank wall 1070 was 150 mm.

The temperature of the electrodeposition bath 1016 is 80 ° C.
2 is 25 ° C., and the transfer speed of the substrate 1001 is 2000
cm / min. The electrodeposition bath 1016 was a bath containing zinc nitrate, and zinc oxide was electrodeposited using zinc as an anode.

The substrate 1001 is made of a stainless steel substrate (SUS
430), the thickness of the zinc oxide film formed on the entire electrodeposition tank was about 1 μm.

At this time, it was confirmed at the substrate take-up roller portion that an extremely large amount of unevenness of the wavy stripe pattern was generated on the zinc oxide film surface. This unevenness was determined to be very slight in the zinc oxide film itself.
After about 1 micron of amorphous silicon was formed by the D method, extremely clear unevenness was observed, and the closed-circuit current characteristics (Jsc) of the solar cell utilizing the unevenness changed according to the unevenness.

When observing the unevenness of the wavy stripe pattern in detail, the stripe is opaque white, and draws an arc with a radius of curvature of several mm to several cm mainly in a direction opposite to the transport direction, and has a width of several tenths of mm. And the border is clear on the side of the stripe transport direction, whereas the border on the side opposite to the stripe transport direction gradually disappears.

When the location where unevenness of the wavy stripe pattern was generated was specified by stopping the substrate transport during the film formation, the location where the overflow cover 1068 was exited and reached the overflow 1064, particularly immediately before the overflow 1064, often occurred. It became clear that. Here, no electrochemical reaction such as electrodeposition was performed.

When the number of overflows 1064 was increased, the occurrence position was shifted to the upstream side in the transport direction. In addition, electrodeposition bath 1
When the bath solution was taken out from step 016, the substrate on which the film was formed was coated with the bath solution, and the substrate after film formation was washed with pure water in another washing tank, and no unevenness was observed.

A bath solution was dropped on the surface of the film on which the zinc oxide film was uniformly formed, and after the solution was dried somewhat, the solution was washed with pure water in another washing tank. The dripping mark of the liquid was formed white with a distinct circular arc.

On the other hand, when pure water was dropped on the film-forming surface on which the film of zinc oxide was formed uniformly and the liquid droplets were dried, no liquid marks were particularly generated.

Even if the unevenness of the wavy stripe pattern appearing on the film-forming surface of the long substrate and the trace of dripping of the bath liquid are both formed once and then washed with pure water in another washing tank, it is easy to obtain the same. The marks could not be erased.

The bath liquid taken out on the film forming surface of the long substrate is
The tendency is remarkable when the drying speed is faster than when the bath liquid is taken out to a stainless steel substrate on which zinc oxide is not formed, and when the temperature of the substrate is increased by being immersed in a high-temperature bath. Was.

Further, the concentration of zinc nitrate in the bath was 0.01 M /
When it was 1, no unevenness of the wavy stripe pattern occurred without changing the substrate transfer speed.

From these investigation facts, it can be seen that "unevenness of the wavy stripe pattern is caused by the fact that the solute taken out of the bath solution is repelled in the course of drying on the film-formed surface of the substrate, and the boundary of the bath solution is wavy. Dried as it is, or swept with overflowing pure water and then turned out at a clear boundary. "

Thus, when the transport speed of the long substrate was increased by a factor of three, unevenness of the wavy stripe pattern hardly occurred.

Separately, pure water overflows 1068
In the vicinity of the exit, pure water was guided by a hose having a closed end and a perforated hole, and water was sprayed on the substrate film formation surface. Unevenness of the wavy striped pattern on zinc oxide was not observed at the substrate winding roller 2062. Even when amorphous silicon was formed by a CVD method to produce a solar cell, no unevenness was observed and uniform characteristics were exhibited.

In this case, when the amount of water sprinkled was small and the drying proceeded quickly, the unevenness of the wavy striped pattern included many arcs in the other direction, which was the opposite effect.

Further, the same result was obtained by using water 1032 in the first washing tank 2032 containing a small amount of the bath, instead of pure water. This is especially true for the first washing tank 203
It shows that water from 2 can be used before being discarded as wastewater.

[0075]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the electrodeposition apparatus of the present invention will be described below, but the present invention is not limited to these embodiments.

The main components of the electrodeposition apparatus of this embodiment have basically the same configuration as the electrodeposition apparatus shown in FIG. 2, but in order to solve the problems in the apparatus. Various improvements have been made. Therefore, for convenience, FIG.
The description is given with the same reference numerals.

That is, the electrodeposition apparatus of the present embodiment is an apparatus for continuously depositing a uniform oxide on the long substrate 2001, and the long substrate 2001 and the anode 2017 are deposited in the electrodeposition bath 2016. An electrodeposition tank 2009 for energizing to form an oxide film on the substrate 2001, and a washing means such as a washing tank 2030 for washing the substrate 2001 having passed through the electrodeposition tank 2009;
A drying unit such as a hot-air drying furnace 2051 for forcibly drying the substrate 2001 that has passed through the water washing unit 2030 is provided. The transfer speed of the transfer unit is optimized, and a liquid spray unit is newly provided. Hereinafter, each component will be described in detail.

[Substrate] The substrate 2001 used in the present invention
Is electrically conductive on the film forming surface, and the electrodeposition bath 20
As long as it is not eroded by 16, a metal such as stainless steel (SUS), Al, Cu, Fe, or an alloy thereof is used. Further, a PET film with a metal coating can be used.

Among these, stainless steel is excellent as a long substrate for performing an element forming process in a later step.

The substrate surface may be smooth or rough. In the case of a submicron or more rough surface, even if a film having good wettability is formed, the electrodeposition tank 2009 and the washing tank 203 are used.
Dry unevenness easily occurs between 0 and 0, and the present invention is effective.

Further, another conductive material may be formed on the substrate 2001, and it is selected according to the purpose of the electro-deflection.

[Electrodeposition tank] As the electrodeposition tank used in the present invention, stainless steel (SUS), F
e, Al, Cu, Cr, brass and the like can be used because they are excellent in heat resistance and workability, and stainless steel is preferable in consideration of corrosion resistance. As the stainless steel, any of ferritic, martensitic, and austenitic stainless steels can be used.

When heat retention is required, a double structure can be used, and the space between the tank walls can be complemented with a heat insulating material. Examples of the heat insulating material include air, oil and fat, glass wool, urethane resin and the like in consideration of temperature and simplicity.

[Electrodeposition bath] As the electrodeposition bath 2016 accommodated in the electrodeposition bath 2009, a well-known bath for metal plating and a bath mainly composed of zinc nitrate for forming a zinc oxide film are used. It is possible. Sugars such as sucrose and dextrin can also be added to increase the uniformity of the film.

In particular, in order to form a zinc oxide film having irregularities on the order of the wavelength of light effective as a light trapping / reflecting layer of a solar cell, the concentration of zinc nitrate is preferably 0.1 M / l or more. In order to obtain a zinc oxide film oriented in the c-axis, it is generally preferred to be 0.05 M / l or less, though it depends on the substrate.

In any case, the added saccharide is preferably 3 g / l or more for sucrose and 0.01 g / l or more for dextrin. In these cases, the temperature of the bath is preferably set to 60 ° C. or higher because no metal is deposited. In particular, when the temperature is 80 ° C. or higher,
This is preferable because the uniformity of the film is improved. Therefore, at these temperatures, the effects of the present invention become more remarkable.

When depositing indium oxide, it is preferable that indium nitrate is made 0.0001 M / l or more and saccharides are contained in the same degree. However, the bath temperature is preferably lower than 60 ° C.

In the case where these oxides are formed to form irregularities, spontaneous drying occurs particularly between the electrodeposition tank 2009 and the washing tank 2030 and unevenness easily occurs. It is.

When a plurality of baths are required, or when the amount of film formation in one bath is not sufficiently large, a plurality of electrodeposition tanks are used. In the latter case, the same electrodeposition tank can be continuously arranged. In these cases, the same concept as entering the washing tank 2030 can be applied, and the speed of the substrate is not dried, or the water or the bath liquid itself is sprayed to prevent drying. Thereby, the present invention is applied.

[Washing Means] As the washing means used in the present invention, a shower for washing may be used in addition to a method in which the substrate 2001 is passed through water contained in a washing tank 2030 as shown in FIG. Even in the latter case, it is difficult to effectively remove the drying unevenness once formed only by washing with water.

In the case where the electrodeposition bath 2016 contains sucrose or the like whose solubility increases as the temperature rises,
Keeping the temperature of the washing water high may also enhance the washing effect, but in that case, the humidifying means of the present invention is applied between the washing tanks as needed.

[Drying means] In the drying means used in the present invention, after sufficiently removing water-soluble solutes, draining with an air knife as shown in FIG. 2 is extremely effective. Warm air is enough. When a vacuum device is used in a later step, an infrared heater or the like can be used to remove adsorbed water.

[Transporting Means] In the substrate transferring means used in the present invention, 0.5 mm per 1 cm of the width of the substrate is used so that vertical vibration of the substrate does not occur and step-like unevenness occurs between the tanks.
Preferably, a tension of at least kg is applied.

In particular, the vertical movement at the overflow portion is as follows.
Since unevenness due to overflow or droplets is likely to occur, it is preferable to secure a transport path using the support roller as a magnetic roller (in the case of a ferromagnetic substrate).

In the present invention, the conveying speed of the conveying means is
It is preferable to set the speed at which the bath liquid taken out from the electrodeposition bath 2016 to the substrate surface passes between the tanks in a shorter time than the time required for the bath liquid to naturally dry and precipitate solute in the transport path between the tanks. . When the long substrate 2001 is transported at such a transport speed, the bath solution taken out from the electrodeposition tank 2016 to the substrate surface is transported to the washing tank 2030 or the like until the bath liquid is naturally dried. No precipitation occurs and no wavy striped pattern unevenness occurs.

Although FIGS. 1 and 2 show horizontal transfer of a substrate due to overflow, the present invention can be similarly applied to oblique transfer of a substrate using a folding roller between tanks.

[Spraying means] As the sprinkling means used in the present invention, in addition to the hose having a closed end and a fine hole used in the examination experiment, a nozzle, a shower, and the like are used. Sprinkles are
It is preferable that droplets are continuously applied to the film-forming surface of the substrate, rather than sprayed in the form of mist. This is to generate a sufficient liquid flow to effectively dilute or discharge the solute in the taken-out bath liquid.

As the liquid to be sprayed, in addition to pure water, the same bath as the preceding electrodeposition bath or a mixture of the same and water is used.

[0099]

EXAMPLES Examples based on the present invention will be described below, but the present invention is not limited to these examples.

Example 1 In the electrophoresis apparatus shown in FIG. 2, a shower nozzle was arranged between an electrodeposition tank 2009 and a washing tank 2030, and pure water was sprayed at a flow rate of 300 ml / min. Pure water whose surface had been tanned was disposed of as it was because the concentration of solute in the bath solution was high.

The substrate 2001 used was a 2D-processed stainless steel substrate (SUS430) having a thickness of 0.12 mm, and formed by sputtering thin aluminum of 1000 mm and smooth zinc oxide of 2000 mm as an underlayer. .

The reason why aluminum is formed is to secure the reflectance when the photovoltaic element is formed.

The reason why the smooth zinc oxide is formed is to improve the adhesion and to control the particle size in the electrodeposition step, that is, the size of the unevenness, to the order of the wavelength of light. The reason for forming the irregularities controlled to about the wavelength of light is to obtain a solar cell having an excellent closed-circuit current (Jsc) by using the electrodeposited film according to the present invention as a reflective layer and making effective use of reflected light. .

The support roller 1014 and the support roller 1031 in FIG. 1 use a magnet roller having a surface magnetic flux density of 1100 gauss to lift the substrate upward so that the substrate is fed at a predetermined position. Note that the stainless steel substrate 2001 used in this example is a SUS430 ferrite-based material and therefore has magnetism.

The feed speed of the substrate is set to 500 mm / min, and the support roller 1014 and the support roller 1031 are driven by the transfer of the substrate to prevent the non-deposited surface of the substrate from being damaged.

The transport tension was 2.5 cm per 1 cm width of the substrate.
kg. There was almost no vibration or displacement of the substrate during the transfer, and the substrate surface was held extremely close to flat.

Ultra-pure water is used for washing, and as shown in FIG. 2, a third washing circulation tank 2049 to a first washing circulation tank 2047.
Inflow was made to occur in order. At this time, the concentration of zinc ions due to the introduction of the bath liquid from the electrodeposition bath in the first washing circulation tank 2047 was 66 ppm, indicating a sufficient washing effect.

The drying was controlled so that the atmosphere temperature of the hot air drying furnace 2051 was 80 ° C. 7 kW hot air generator 2
Using 055, the air temperature immediately after exiting from the hot-air blowing pipe 2052 was 150 ° C.

The electrodeposition bath 2016 contains zinc nitrate at 0.2 M /
1 and dextrin dissolved at a rate of 0.7 g / l were used overnight. The bath temperature was 85 ° C., and the flow rate of the air used for air stirring was 20 m ³ / hr.

A 4N zinc plate was used for the anode 2017, and 2 mA /
flowing cm ² of current density electrodeposition析電flow zinc oxide 1.2
It was formed with a thickness of microns. Zinc oxide was an aggregate of polycrystals, and it was confirmed from a scanning electron microscope (SEM) image that each of the polycrystals had a size of about 1 micron.

Using this film as a reflection layer, a CV for a long substrate is used.
A so-called triple cell was formed by a D film forming apparatus by combining three elements of a pin composed of a-SiGe (a- means amorphous) and a-Si, and used as a photovoltaic layer of a solar cell. On this semiconductor layer, ITO was formed at 700 ° by sputtering to form an upper electrode.

The solar cell was subjected to IV measurement under simulated sunlight to examine its characteristics.

I when the droplet shower was not operated
The V characteristics varied according to the unevenness of the wavy stripe pattern that was visually observed. Particularly the white boundary, the series resistance in comparison with the normal value 24 ohms / cm ^2, were greatly varied with ^{90Ω / cm 2 ~200Ω / cm 2} . For this reason, there was also a problem in characteristics such as a warp in the IV curve. 6.6 mA / c for Jsc
m ² or less.

On the other hand, when the droplet shower was operated, no unevenness could be visually confirmed, and the series resistance was in the range of 23 Ω / cm ^{2 to} 28 Ω / cm ^2.
Each V curve showed a good shape. Jsc is 7.
And 0mA / cm ² ~7.3mA / cm ² was in the good range. Thus, the effect of the present invention was extremely large.

Example 2 Another electrodeposition tank was added to the electrodeposition apparatus shown in FIG. The additional electrodeposition tank was configured in exactly the same transfer method, that is, horizontal transfer, between the electrodeposition tank 2009 and the washing tank 2030 in FIG. The concentration and temperature of the electrodeposition bath used in the additional electrodeposition bath and the original electrodeposition bath 2009 were the same.

The same means for spraying pure water as in Example 1 is provided between the added electrodeposition tank and the washing tank 2030, and between the original electrodeposition tank 2009 and the added electrodeposition tank. Also provided the same spraying means, but here, the bath used in the electrodeposition bath was sprayed.

In Example 2, as in Example 1, no unevenness of the wavy stripe pattern occurred. According to the present embodiment, not only the unevenness of the wavy stripe pattern on the film-forming surface can be drastically reduced as in the first embodiment, but also the addition of an electrodeposition tank makes it possible to reduce the thickness of zinc oxide to a sufficiently large thickness. Electrodeposition could be easily performed.

Example 3 An additional electrodeposition tank was provided in the same manner as in Example 2, and the transfer of the long substrate 2001 between the original electrodeposition tank 2009 and the added electrodeposition tank was performed by changing the surface of the substrate. This was done via abutting rollers.

The roller used was a PFA wound on a stainless steel structure.
A bath solution was simultaneously sprinkled on the roller and the substrate deposition surface.

In Example 3, as in the case of Examples 1 and 2, no unevenness of the wavy stripe pattern occurred. According to the present embodiment, since it is not always necessary to limit the transport direction of the substrate to a horizontal direction, the degree of freedom in the design of the entire electrodeposition apparatus is greatly improved, and an excellent reflective layer for a solar cell is extremely inexpensively and stably provided. Can be provided.

[0121]

As described above, according to the present invention,
Until the bath liquid taken out from the electrodeposition tank to the substrate surface is conveyed to the washing tank before it dries naturally, solutes do not precipitate and uniform oxidation without wavy stripe pattern unevenness on long substrates The film can be uniformly deposited, and is suitable for a reflective layer of a solar cell.

By maintaining the temperature of the electrodeposition bath at 60 ° C. or higher, more preferably at 80 ° C. or higher, stable electrodeposition can be performed in an electrodeposition process requiring a high temperature such as zinc oxide.

By providing a plurality of electrodeposition tanks, even if the transport speed of the substrate is increased, it is possible to easily deposit zinc oxide having a sufficiently large thickness.

Since a spraying means for preventing the bath liquid taken out of the electrodeposition bath to the substrate surface from drying is provided,
The solute in the bath liquid taken out of the electrodeposition tank can be effectively diluted or discharged.

When a plurality of washing tanks are provided as the washing means, the humidifying means for providing moisture to the substrate surface is provided between the washing tanks, so that the unevenness of the wavy stripe pattern on the film-forming surface is provided. Is prevented, and even when the electrodeposition bath contains saccharides such as sucrose, the temperature of the washing water can be kept high to enhance the washing effect.

Further, by using a roller in contact with the substrate surface as the transfer means, it is not always necessary to limit the transfer direction of the substrate to a horizontal direction, and the degree of freedom in designing the entire electrodeposition apparatus is greatly improved.

The oxide formed in the electrodeposition bath is zinc oxide, the solvent of the bath solution is water, and the solute precipitated by drying is zinc nitrate. Thus, a reflective layer having a sufficient light confinement effect can be obtained, and a photovoltaic device having excellent characteristics can be manufactured.

[Brief description of the drawings]

FIG. 1 is an enlarged schematic view showing the vicinity of a connection between an electrodeposition tank and a washing tank in the electrodeposition apparatus of the present invention.

FIG. 2 is a schematic diagram showing an example of a device to which the present invention can be applied.

[Explanation of symbols]

1001 Substrate 1014, 1031 Supporting roller 1016 Electrodeposition bath 1063, 1064 Overflow 1065, 1066 Drainage blade 1067 Electrodeposition tank wall 1068, 1068 Overflow cover 1070 Rinse tank wall 1031 Supporting roller 2001 Long substrate 2002 Substrate feeding roller 2003 Roller 2005 Tension detection roller 2006 Power supply roller 2007, 2058 Stopper 2008 Power supply 2009 Electrodeposition tank 2062 Substrate winding roller 2010-2012 Steam discharge duct 2013, 2014, 2031, 2057, 2066
Support roller 2015 Power supply bar 2016 Electrodeposition bath 2017 Anode 2018 Air blowing pipe 2019 Stirred air introduction pipe 2020 Electrodeposition bath liquid supply pipe 2021, 2022, 2038-2043 Valve 2023 Bath circulation pump 2024 Heater 2025 Electrodeposition circulation tank 2026 Steam Discharge duct 2027 Circulation pump 2029 Electro-Financing tank 2030 Rinse tank 2032 First rinse tank 2033 Second rinse tank 2034 Third rinse tank 2035-2037 Supply pipe 2044-2046 Water circulation pump 2047-2049 Rinse tank 2051 Hot air drying oven 2052 Hot air blowing pipe 2053 Hot air collecting pipe 2054 Filter 2055 Hot air generating furnace 2056 Outside air introduction pipe 2059 Meandering correction roller 2060 Interleaf paper feeding roller 2066 Air knife

(72) Inventor Yusuke Miyamoto 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (11)

[Claims] 1. An electrodeposition tank for applying an electric current to a long substrate and an electrode in an electrodeposition bath to form an oxide film on the substrate, a washing means for washing the substrate passing through the electrodeposition tank with water, And a drying means for forcibly drying the substrate that has passed through the means, wherein the transport means for the long substrate comprises a bath liquid taken out of the electrodeposition bath to the substrate surface and transported between the tanks. An apparatus for electrodeposition of a long substrate, wherein the apparatus has a transport speed that passes between tanks in a shorter time than the time required for air-drying naturally to precipitate a solute. 2. The electrodeposition apparatus according to claim 1, wherein the electrodeposition bath contains a saccharide. 3. The electrodeposition apparatus for a long substrate according to claim 1, wherein the temperature of the electrodeposition bath is 60 ° C. or higher. 4. The apparatus according to claim 1, wherein the temperature of the electrodeposition bath is 80 ° C. or higher. 5. The apparatus for depositing long substrates according to claim 1, wherein a plurality of electrodeposition tanks are provided in the substrate transport path. 6. A spraying means is provided at least on a transport path on the outlet side of the electrodeposition tank for spraying liquid on a substrate passing through the electrodeposition tank and preventing drying of a bath liquid taken out on the surface thereof. The electro-finish apparatus for a long substrate according to any one of claims 1 to 5, wherein: 7. The electrodeposition apparatus for a long substrate according to claim 6, wherein water, water, the same bath as the preceding electrodeposition bath, or a mixture of water and water is used as the liquid. 8. When a plurality of rinsing tanks are provided as rinsing means, and the temperature of the rinsing water is high enough to easily dry the substrate surface in the transport path, the rinsing means is used to apply moisture to the substrate surface between the rinsing tanks. The electrodeposition apparatus for a long substrate according to any one of claims 1 to 7, further comprising a humidifier. 9. The apparatus according to claim 1, wherein a roller in contact with the surface of the substrate is used as the transport means. 10. The electrodeposition of a long substrate according to claim 1, wherein when the substrate is a ferromagnetic material, a magnet roller in contact with the upper surface of the substrate is used as the transport means. apparatus. 11. The method according to claim 1, wherein the oxide formed in the electrodeposition bath is zinc oxide, the solvent of the bath solution is water, and the solute precipitated by drying is zinc nitrate. ~ 1
0. An electrodeposition apparatus for a long substrate according to any one of the items [1] to [3].