JP3173318B2 - Etching method and method for manufacturing semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching method, a method for manufacturing a semiconductor device, and an etching agent which can be used for the method, and more particularly, to a simple and excellent selection accuracy, damage to non-etched regions and non-etched layers. The present invention relates to an etching method capable of greatly reducing the temperature, a method of manufacturing a semiconductor device such as a photovoltaic device having excellent characteristics by using the etching method, and an etching agent usable in the method.

[0002]

2. Description of the Related Art Etching technology is widely used in the process of manufacturing semiconductor devices for various uses such as solar cells and photodiodes, which are one of photovoltaic devices.

For example, in a semiconductor element such as a diode or an IC, it is used for patterning and separating an electrode or a base material or a semiconductor layer of a metal conductive film or a transparent conductive film.

[0004] In semiconductor elements such as solar cells, they are used for patterning and separating transparent conductive films and electrode semiconductor layers. Conductive layers in integrated solar cells
It is used for separation patterning of semiconductor layers.

More specifically, for example, in an amorphous silicon solar cell, it is used for patterning and separation of a transparent conductive film provided on a light-transmitting substrate, or provided on an amorphous silicon layer. It is used for patterning separation of a transparent conductive film.

A description will be given of a schematic example of a specific manufacturing process. A transparent conductive film is formed on a light-transmitting insulating substrate, a predetermined pattern of a solar cell is formed by etching the film, and an amorphous silicon layer serving as a photoelectric conversion layer is formed on the patterned transparent conductive film. Is used for an amorphous silicon solar cell manufactured by forming a back electrode thereon.

[0007] Separately, an amorphous silicon layer is formed on a metal substrate, and then a transparent conductive film is formed. This film is patterned by etching, and a current collector such as silver is formed thereon. Used in amorphous silicon solar cells manufactured by forming grid electrodes for use.

[0008] As a method of patterning by selective etching after forming a transparent conductive film on a substrate, Japanese Patent Application Laid-Open No. 55-108779 and US Pat.
Chemical etching methods such as those disclosed in US Pat.

An example of a method for patterning a transparent conductive film will be described more specifically. First, a photoresist formed by silk screen printing, flexo printing, or another printing method on a transparent conductive film, or by spinner or printing is exposed and developed with a desired pattern to form a desired positive pattern of the resist. Next, the transparent conductive film corresponding to the negative portion of the resist pattern (the exposed portion of the transparent conductive film) is removed by etching with an etching solution such as a ferric chloride solution or a nitric acid solution which is an acidic solution. The transparent conductive film corresponding to the pattern is left. Alternatively, the negative portion of the resist pattern is processed by a dry etching method such as plasma etching to leave a transparent conductive film corresponding to the resist pattern. Then, the resist pattern (printing ink such as silk screen ink or resin, resin,
The transparent conductive film having a desired pattern shape was obtained by dissolving and / or stripping and removing the pattern of the cured product of the photoresist with a stripping agent, or by removing with a dry process (such as plasma ashing). .

However, in the conventional patterning by the etching method, there are many steps before and after the formation of a positive pattern of a resist using a photoresist or the like, exposure, development, peeling of the etching resist, post-processing and etching.

Further, since the chemical etching is performed in an etching solution, the etching accuracy may be reduced due to expansion and peeling of the resist. Strict solution temperature control is also required.

[0012] On the other hand, although dry etching can perform precision cross-field patterning, the processing speed is slow, the processing capability of the apparatus itself is low, and as a result, the manufacturing cost is high.

In some cases, a very strong oxidizing agent is required for removing the photoresist. Strong oxidants are dangerous to handle and difficult to dispose of. Although the removal of the resist by the plasma ashing method can be said to be a non-polluting resist removal method without using a solution, it cannot be used for all the resists.

On the other hand, in a solar cell formed through a step of patterning by etching a transparent conductive film, a short circuit, a shunt, or a poor appearance may occur when a patterning defect (patterning line disconnection, etc.) occurs. As a result, characteristics such as conversion efficiency may be degraded, performance may be varied, or manufacturing yield may be reduced.

[0015]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and has an improved number of processing steps, is simple, has excellent selection accuracy, and has very little etching damage. It is another object of the present invention to provide a method for manufacturing a semiconductor device having a process utilizing the method.

Further, according to the present invention, a material to be etched including a film to be etched can be stably etched, a process defect does not occur, and a low cost and efficient etching process can be performed on a film to be etched. It is an object of the present invention to provide a method and a method for manufacturing a semiconductor device having a process utilizing the method.

In addition, the present invention provides a method of manufacturing a semiconductor device having a process utilizing a method of etching a film to be etched which has a high yield and has no short circuit or shunt or poor appearance which may be caused by poor etching. The purpose is to:

It is a further object of the present invention to provide an etching agent having stable properties even when stored for a long time.

In addition, the present invention provides an etching method suitable for etching a conductive film, and further, a transparent conductive film, a method for manufacturing a semiconductor device having the etching method, and an etching agent usable for the method. It is.

[0020]

[0021]

According to the present invention, there is provided a method of manufacturing a semiconductor device, comprising the steps of: disposing a paste having fine particles made of at least one kind of polymer resin and an etching solution on a material to be etched; Heat-treating the paste on the material at a temperature not lower than 100 ° C. and not higher than the melting point of the fine particles.

The etching agent of the present invention desirably has an etching solution and at least one kind of polymer fine particles.

[0023]

(Etching) The reason why a good etching pattern can be obtained by the present invention is considered as follows.

Generally, in a method called chemical etching, an etching solution such as an acid or an alkali is used. Here, atoms on the surface of the film to be etched react with the etching solution, and the resulting reaction product is dissolved and removed.

On the other hand, for example, as a transparent conductive film used for an amorphous solar cell or the like, SnO ₂ , In ₂ O ₃ , I, which have excellent characteristics in terms of transparency to visible light and electric conductivity, are used.
For example, a TO (In ₂ O ₃ + SnO ₂ ) film is used. The method for producing these transparent conductive films includes vacuum deposition, ionization deposition, sputtering, CVD, and plasma CV.
A method D, a spray method, or the like can be used, and is appropriately selected as desired.

These transparent conductive films are formed by applying heat while being brought into contact with an etching solution such as the above-mentioned acid or alkali, ie, a concentrated sulfuric acid, a concentrated hydrochloric acid, an iron chloride solution or the like. Reacts and dissolves with the etching solution. Therefore, it is possible to etch the transparent conductive film by immersing the substrate on which the transparent conductive film is formed in an etching solution and heating the substrate.

However, in order to pattern the transparent conductive film into a desired pattern, as described above, the surface is masked corresponding to the portion where the transparent conductive film is desired to be left, and the resist pattern is not contacted with the etching solution. Formation is indispensable, and complicated patterning is performed using a photosensitive agent commonly called a photoresist.

In the present invention, instead of using an etching solution alone and bringing a transparent conductive film having a resist formed on the surface into contact with the solution, a paste kneaded with polymer fine particles is placed on the transparent conductive film. Lamination and patterning are performed simultaneously. Therefore, patterning with a mask is not required. In addition, a pre-etching step such as formation, exposure and development of a positive pattern and a post-etching step such as stripping of a mask are not required, so that the number of steps can be greatly reduced. Further, by heating to 100 ° C. or higher, the reaction between the etching solution and the transparent conductive film can be accelerated, and the etching time can be shortened. If the temperature is lower than 60 ° C., the reaction between the etching solution and the transparent conductive film is insufficient, so that the line width of the line obtained by patterning may be non-uniform or the wire may be disconnected. In addition, since the present invention does not mean that the entire substrate is immersed in the etching solution, even when etching the transparent conductive film on the multilayer, the solution affects the film below the transparent conductive film. Things can be avoided.

In the present invention, the polymer fine particles serve to increase the viscosity by kneading with the etching solution. Since the paste having the increased viscosity is not in a liquid state, it is possible to perform patterning without anyone by shortening the processing time. The paste can be easily obtained by using the fine particles of the polymer resin as the material of the fine particles.

As the polymer resin used, acrylic resin such as polymethyl methacrylate, silicone resin,
Benzoguanamine resin, fluorine resin such as ethylene tetrafluoride resin and polyvinyl fluoride, urethane resin, and polystyrene resin are preferably used. These polymer resins are further imparted with solvent resistance and acid resistance, so that the corrosion resistance is improved and a more stable paste can be obtained.

When heating at a temperature of 100 ° C. or more to accelerate the etching reaction, a molecular resin having a melting point higher than the heating temperature is preferably used so that the composition or state does not change at the heating temperature. By selecting such a polymer resin, the polymer resin does not change by heating at the time of etching, so that the polymer particles do not change or react unnecessarily during the reaction of the etchant in the paste. In addition, it is possible to avoid the adverse effects such as the fact that the paste is hardly removed by binding to the substrate.

The shape of the polymer fine particles is basically a homogeneous spherical particle, but may be of various shapes other than the above. The structure may be a mixed structure of various polymers or a laminated structure. The structure may be a composite particle structure with another material.

Further, by uniformly kneading and dispersing the polymer fine particles and the etching solution, in the portion where the paste is provided on the film to be etched such as a transparent conductive film,
The etching solution can uniformly contact and react with a film to be etched such as a transparent conductive film, and a uniform pattern can be formed. It is desirable that the particle size of the polymer fine particles used in the present invention is designed to be as small as possible to be homogeneously dispersed. Specifically, the average particle diameter is preferably 20 μm or less, more preferably 0.1 μm to 20 μm, and further preferably 0.2 μm to 10 μm.

When the printing method is used, it is preferable to improve the printability by imparting flexibility to the polymer fine particles or adding lubricating properties by adding glycerin or the like. The average particle size, the amount of glycerin added, and other thickeners that increase the viscosity of the paste, diluents that lower the viscosity of the paste, such as water, and control the corrosiveness, and the amount of the addition depend on the line width and accuracy of etching. It is preferable to appropriately select and mix them together.

A known method is used to form the paste in a desired pattern on a film to be etched such as a transparent conductive film. That is, since it has a certain degree of viscosity, screen printing is possible, and pattern formation can be performed using a plate on which desired patterning has been formed. Further, a simple pattern can be formed by using a coating method or a dotting method. Further, the paste may be applied by a dispenser.

The thickness of the paste is appropriately determined depending on the material, thickness and range of a film to be etched such as a transparent conductive film to be removed by etching.
It is preferably at least m and less than 2 mm. In most cases, when the thickness is 10 μm or more, the etchant in the paste reacts sufficiently with the film to be etched such as a transparent conductive film, and a pattern can be formed without an unetched portion. When the thickness is less than 2 mm, the paste is dripped in a lateral direction. Does not occur, and a pattern having a uniform line width can be formed.

After laminating the pastes, they are heated under a desired condition using a warm air oven or an IR (infrared) oven. It is effective to heat at a high temperature in order to accelerate the etching reaction, and it is desirable to set the temperature to 100 ° C. or higher. Further, by heating to 100 ° C. or higher to accelerate the reaction, dripping of the paste can be prevented, and more favorable patterning can be performed. After the heating is completed, the paste is washed off with water or a solvent and removed. A higher than the heating temperature of the melting point of the polymer microparticle material used, particulate matter is thermally stable even at the time of heating, it without reacting with fine particles, easily since no forms an wear substrate by melting Is removed.

Next, a photovoltaic device 200 which is one of the semiconductor devices manufactured by using the etching method of the present invention.
Will be described with reference to FIG. In the figure, 201 is a supporting substrate, 202 is a lower electrode, 203, 204, and 205 are semiconductor layers respectively, 206 is a transparent conductive film as an upper electrode, 207 is a portion obtained by removing the transparent conductive film by etching, and 208 Represents a grid electrode.

A lower electrode 202 is formed on a supporting substrate 201, and a non-single-crystal semiconductor layer 203, 204, 20 having an amorphous, polycrystalline or microcrystalline structure is formed on the lower electrode 202.
5 are sequentially stacked. This non-single-crystal semiconductor layer 203,
Those having silicon atoms 204 and 205 are preferably used. Specifically, a semiconductor layer having an amorphous silicon-based semiconductor is preferable. Non-single-crystal semiconductor layers 203 and 2
04 and 205 are generally n-type (p-type), i-type and p-type (n
Type). The semiconductor layer 204 may be further divided into multilayer regions. For example, the semiconductor layer 204 may be divided into three regions, and a non-single-crystal silicon semiconductor region may be provided above and below, and a non-single-crystal silicon germanium semiconductor region may be provided therebetween.

In addition to the so-called single cell type having one set of nip type (or pin type) as shown in FIG. 1, a so-called tandem cell type having two sets or a so-called triple cell type having three sets (FIG. 2) ) Or more.

In FIG. 1, a transparent conductive film 206 as an upper electrode is formed on a semiconductor layer 205, and is patterned into a desired pattern to form an upper electrode. A grid electrode is formed on the transparent conductive film 206 as needed.

Although it is necessary to increase the area to obtain more power by using a solar cell, the conversion efficiency tends to decrease as the area increases. This is a transparent conductive film 2
The main cause is power loss due to the resistor No. 06. Therefore, the effective area of the solar cell is determined from the relationship with the current collection efficiency of the grid electrode 208.
By performing the patterning accurately, the effective area of the solar cell is increased, and the output is improved.

If the patterning line 207 is not formed as desired at the time of patterning, a leak current is generated from a shunt portion outside the effective area, causing a reduction in efficiency. Therefore, it is necessary that the transparent conductive film be completely removed during the etching.

[0045]

Next, another embodiment of a solar cell (of a photovoltaic element) to which the present invention can be suitably applied will be described with reference to the drawings.

FIGS. 2 and 3 schematically show preferred examples of the structure of a solar cell to which the present invention can be applied.

The photovoltaic element shown in FIG. 1 is an example of an amorphous silicon solar cell having a single cell structure in which light enters from the side opposite to the substrate, for example, as shown in FIG. Alternatively, an amorphous silicon solar cell having a triple structure may be used.

FIG. 3 is a view of the solar cell of FIGS. 1 and 2 viewed from the light incident side. In FIG. 3, the size of the substrate 201, the lower electrode 202 provided thereon, and the semiconductor layers 203, 204, 205 (or the semiconductor layers 203, 20)
4,205,213,214,215,223,22
4, 225), and the case where the outer periphery of the transparent conductive film 206 is matched.

Further, although not shown, it goes without saying that the structure using the concept of the present invention can be applied to an amorphous silicon solar cell deposited on a transparent insulating substrate.

(Substrate) The substrate 201 is a member for mechanically supporting the semiconductor layers 203, 204, and 205 in the case of a thin-film solar cell such as amorphous silicon, and is used as an electrode in some cases. The substrate 201 includes semiconductor layers 203 and 20
4,205 is required to have heat resistance to withstand the heating temperature at the time of forming the film, and may be a conductive material or an electrically insulating material.
Cr, Al, Mo, Au, Nb, Ta, V, Ti, P
Metals such as t, Pb, and Ti or alloys thereof, for example, thin plates such as brass and stainless steel and composites thereof, carbon sheets, galvanized steel plates, and the like. Examples of the electrically insulating material include polyester, polyethylene, polycarbonate, and the like. Cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, epoxy or other heat-resistant synthetic resin film or sheet or a composite of these with glass fiber, carbon fiber, boron fiber, metal fiber, etc. And metal thin films of different materials and / or SiO ₂ , Si ₃ N ₄ ,
Examples thereof include those obtained by subjecting an insulating thin film such as Al ₂ O ₃ or AlN to a surface coating treatment by a sputtering method, a vapor deposition method, a plating method, or the like, glass, ceramics, and the like, or a laminated structure thereof.

(Lower electrode) The lower electrode 202 is one electrode for extracting electric power generated in the semiconductor layers 203, 204, and 205, and has a work function that makes ohmic contact with the semiconductor layer 203. Is required. The material is A
1, Ag, Pt, Au, Ni, Ti, Mo, W, Fe,
V, Cr, Cu, stainless steel, brass, nichrome Sn
A so-called simple metal or alloy such as O ₂ , In ₂ O ₃ , ZnO, and ITO, and a transparent conductive oxide (TCO) are used.

The surface of the lower electrode 202 is preferably smooth. However, in the case of causing irregular reflection of light, irregularities may be formed and textured as necessary. When the substrate 201 is a conductive material that makes ohmic contact with the semiconductor layer 203, the lower electrode 202 is not necessarily provided. The lower electrode is plated, evaporated,
It can be formed by a method such as sputtering.

(Semiconductor Layer) As described above, a non-single-crystal material containing an amorphous material, a polycrystalline material, a microcrystalline material, or a mixture thereof can be used for the semiconductor layer.

As described above, as the non-single-crystal semiconductor layer, an amorphous silicon-based semiconductor can be preferably used. Among them, a-Si: H: , A-Si: F, a-S
i: H: F, a-SiGe: H, a-SiGe: F, a
-SiGe: H: F, a-SiC: H, a-SiC :,
So-called group IV and group IV alloy-based amorphous semiconductors such as SiC: H: F are suitable materials.

P-type or n-type semiconductor layers 203 and 2 provided on both sides of i-type semiconductor layer 204.
The semiconductor material constituting 05 is obtained by doping a valence electron controlling agent into the semiconductor material constituting the above-described i-type conductivity type layer.

Specifically, examples of the valence electron controlling agent for obtaining a p-type semiconductor include an element of Group III of the periodic table, and a compound containing this element is used as a raw material. Group III elements include B, Al, Ga, In
And B is particularly preferred.
Examples of a valence electron controlling agent for obtaining an n-type semiconductor include an element of Group V of the periodic table, and a compound containing this element is used as a raw material. Group V elements include:
P, N, As, and Sb are included, and P and As are particularly preferable elements.

As a method of forming the amorphous silicon semiconductor layer, a vapor deposition method, a sputtering method, an RF plasma CV
D method, microwave plasma CVD method, VHF wave plasma CVD method, ECR method, thermal CVD method, LPCV method, optical CV
Known methods such as Method D can be used as desired. As a method adopted industrially, an RF plasma CVD method in which a raw material gas is decomposed by RF plasma and deposited on a substrate is preferably used. Further, in the RF plasma CVD method, the decomposition efficiency of the raw material gas is as low as about 10%, and the deposition rate is 1Å / sec to 10Å / sec.
The problem is that it is as slow as c, but microwave plasma CVD and VHF wave plasma CVD have attracted attention as a film formation method that can improve this point.

As a reaction apparatus for performing the above film formation,
Known devices such as a batch type device and a continuous film forming device can be used as desired. The semiconductor device of the present invention, particularly a solar cell, can also be used in a so-called tandem cell or triple cell in which two or more semiconductor junctions are stacked for the purpose of improving spectral sensitivity and voltage.

(Upper Electrode) As a material usable for the upper electrode, a material usable for the lower electrode can be basically applied. Whether a light-transmitting electrode or a light-blocking electrode is used is appropriately determined depending on whether light is incident on the element from the upper electrode side or the substrate side.

As the upper electrode, a resistance heating evaporation method, an electron beam heating evaporation method, a sputtering method, a spray method, or the like can be used, and is appropriately selected as desired.

Of course, a method and a forming temperature that do not adversely affect the previously formed semiconductor layer and lower electrode are employed.

FIG. 7 is a schematic cross-sectional view for explaining an example of the layer structure of another semiconductor device as a solar cell (light-activated semiconductor device).

As shown in FIG. 7, it has a structure including a photovoltaic device 400 to be manufactured, a substrate 401, a first electrode 402, a semiconductor 404, and a second electrode 406. FIG. 7 also shows the first groove 403 etched, the second groove 405 etched in the semiconductor layer, and the groove 407 etched in the second electrode layer.

This structure is formed as follows. First, a first electrode layer is deposited on a substrate 401, and the first electrode layer is patterned by etching to form a first groove 403 and a first electrode 402. A semiconductor layer is deposited on the first electrode 402 and the substrate 401, and the semiconductor layers are separated by a second groove 405 formed by etching the semiconductor layer to form a semiconductor 404.

Subsequently, a second electrode layer was deposited on the semiconductor and the first electrode, and the second electrode layer was formed by etching the second electrode layer to form the second electrode 406. Separated by groove 407.

The above-mentioned grooves are formed by removing the respective electrode layers or the semiconductor layers using the etching paste of the present invention.

The solar cell shown in FIG. 7 is obtained by the above-described steps. The solar cells are arranged side by side in the horizontal direction, and a plurality of semiconductors are connected in series.

[0068]

Next, an etching method using a paste obtained by kneading a polymer fine particle and an etching solution according to the present invention will be described in detail with reference to the drawings as necessary.

(Test Example 1) FIGS. 1 and 2 are schematic cross-sectional views for explaining patterning in this embodiment.

First, an SnO ₂ film 102 was formed on a glass substrate 101 of 11 cm × 11 cm square by a spray method. Note that the film formation temperature was 450 ° C. and the film thickness was 450 nm.

Next, an etching paste was prepared as follows. First, 57 g of ferric chloride (hexahydrate) having water of crystallization was melted by heating in a hot water bath at 80 ° C. and used as an etching solution, and 40 g of acrylic resin fine particles (acrylic beads) having a particle diameter of 5 μm were added thereto. And 18 g of glycerin were kneaded to prepare a paste. Next, a line having a line width of 1 mm was printed on a screen printing machine (not shown).
The paste 103 was printed at a thickness of 30 μm in a pattern of cm × 10 cm square (FIG. 4), and heated in an infrared oven (not shown) at 170 ° C. for 5 minutes. Thereafter, the substrate was taken out of the oven and cooled, and then the substrate was washed with pure water to remove a paste. This was kept in the oven at 80 ° C. for 3 minutes and dried to obtain a pattern 104 of 10 cm × 10 cm square (FIG. 5). A total of 100 substrates having the same patterning were produced, and the etching was evaluated.

As described above, when the actual line of the patterned substrate was observed and the line width was measured, a uniform patterning line having an average line width of 1.0 mm ± 0.1 mm was obtained. Been formed.

Test Example 2 Transparent polymer particles were prepared in the same manner as in Test Example 1 except that silicone resin fine particles (silicone beads, melting point: 300 ° C.) having a particle size of 10 μm were used as the polymer fine particles and the paste was mixed as follows. The conductive film was patterned, and the line was observed and the line width was measured in the same manner as in Test Example 1. As a result, there was no uneven etching, and a uniform patterning line having an average line width of 1.0 mm ± 0.1 mm was obtained. Had been.

Iron chloride (hexahydrate) 58.8 g Silicone beads 40.0 g Glycerin 18.0 g

Test Example 3 Test Example 1 was repeated except that polymer fine particles were mixed with silicone resin fine particles having a particle size of 5 μm (melting point: 300 ° C.) and acrylic resin fine particles having a particle size of 8 μm (melting point: 250 ° C.) by 50%. The transparent conductive film was patterned in the same manner as described above, and the same observation and line width measurement as in Test Example 1 were performed.
A uniform patterning line of 0 mm ± 0.1 mm was obtained.

Test Example 4 An ITO film (film formation temperature: 450 ° C., film thickness: 500 μm) was formed on the same glass substrate as in Test Example 1 by a sputtering method, and etching and patterning were performed in the same manner as in Test Example 1. Was. Thereafter, the same observation and line width measurement as in Test Example 1 were performed. As a result, there was no etching unevenness and the average line width was 1.0 mm ± 0.1 mm, and a uniform line could be patterned.

Test Example 5 A patterning temperature of 60 ° C.
Except that the temperature was set to 0 ° C., 200 ° C., and 300 ° C., 50 substrates were patterned in the same manner as in Test Example 1. Observation and line width measurement of the manufactured substrate were performed in the same manner as in Test Example 1. Table 1 shows the results.

[0078]

[Table 1]

As shown in Table 1, it is found that the patterning accuracy changes by adjusting the heating temperature even when the same etching paste is used. In particular, the lower the heating temperature, the more the line width becomes non-uniform, but this can be solved by making the etching time appropriate. For example, when the heating temperature is 100 ° C., the line width is 1.0 mm ± without unevenness in the etching for 10 minutes.
It can be 0.1 mm. In other words, by setting an appropriate heating temperature, high-precision patterning without a defective etching portion can be performed in a short time.

Heating at a temperature equal to or lower than the melting point of the particles can prevent the paste from remaining on the substrate after the substrate is washed.
It can be seen that better patterning can be performed in appearance.

Test Example 6 Next, the particle size of the polymer fine particles was adjusted to 0.01 μm and 0.1 μm.
In the same manner as in Test Example 1 except that m, 20 μm, and 30 μm were used, 50 patterned substrates were produced. Observation and line width measurement of the manufactured substrate were performed in the same manner as in Test Example 1. Table 2 shows the results.

[0082]

[Table 2]

As shown in Table 2, it is understood that the patterning accuracy changes even when the same etching solution and glycerin as an additive are used by adjusting the particle diameter of the polymer fine particles.

From the results of the present embodiment, it is particularly clear that the line width is 1.0.
When a pattern of mm is formed, the etching solution is uniformly mixed with the particles by setting the particle diameter of the polymer particles to 0.1 μm to 20 μm, and dripping does not occur. It can be seen that the patterning can be effectively supported and good patterning can be performed.

Of course, in consideration of the screen and the patterning line width, good etching can be performed even with a polymer particle having a particle diameter of 0.01 μm or 30 μm.

(Comparative Example 1) A transparent conductive film was patterned in the same manner as in Test Example 1 except that a protein fine particle having a particle size of 10 μm was used instead of the polymer fine particles, and then the same as in Test Example 1. Observations were made.

As a result, a residue of the etching paste was observed on the substrate after cleaning the substrate. Line width is 0.1mm ~
It was nonuniform with 2.0 mm.

Test Example 7 As an example of the present invention, a method of manufacturing an amorphous solar cell 200 (FIG. 1) having a pin-junction type and including an etching patterning step according to the present invention will be described.

First, a sufficiently degreased and cleaned SUS substrate S
US430BA substrate 201 was placed in a DC sputtering apparatus (not shown), and Ag was deposited to a thickness of 4000 mm, and then ZnO was deposited to a thickness of 4000 mm on the Ag to form lower electrode 202. The substrate is taken out of the DC sputtering apparatus, and R (not shown) is used.
F plasma CVD film forming apparatus, n layer 203, i layer 2
04 and a p-layer 205 were deposited in this order. After that, the substrate is taken out from the RF plasma CVD film forming apparatus,
An ITO film is formed as a transparent conductive film 206 having a function also as an anti-reflection effect (film formation temperature: 450 ° C., film thickness: 700 ° C.), and the substrate is taken out from the vapor deposition device. Was.

Next, a paste was prepared in the same manner as in Test Example 1, and a line having a line width of 1 mm as shown in FIG.
Infrared oven 170 (not shown) printed on corner pattern
Heated at ° C. for 5 minutes. After removing the substrate from the oven and cooling, the substrate is washed with pure water to remove the paste,
A 10 cm × 10 cm square pattern 207 was obtained. This was kept in the oven at 80 ° C. for 3 minutes and dried. Further, a grid electrode 208 for current collection was formed by screen printing of a silver paste.

As described above, 100 patterned amorphous solar cells were manufactured, and their initial characteristics were measured as follows.

First, voltage-current characteristics in a dark state were measured.
When the shunt resistance was determined from the inclination near the origin, it was 120.2 kΩcm ² on average.

Next, a pseudo solar light source (SP) having a light amount of 100 mWcm ^{2 in} the sunlight spectrum of AM1.5 global
The solar cell characteristics were measured using IRE (manufactured by IRE), and the conversion efficiency was determined. The result was 7.5% on average.

When the same observation as in Test Example 1 was performed, the transparent conductive film 206 formed of an ITO film was free from defective unetched portions and uneven etching, had a uniform line width, and was patterned very well. I was

As described above, the solar cell manufactured by using the etching of the present invention exhibited good characteristics without unnecessary short circuit, shunt, and disconnection.

(Test Example 8) A transparent conductive film was patterned in the same manner as in Test Example 7 except that the polymer fine particles were made of polyethylene resin fine particles having a particle diameter of 8 µm, thereby producing 100 amorphous solar cells. did.
Next, when the initial characteristics were measured in the same procedure as in Test Example 7, the shunt resistance was 115.5 kΩcm ^{2 on} average, and the conversion efficiency was 7.5% on average.

When the same observation as in Test Example 1 was made, it was found that the transparent conductive film had no defective unetched portions or uneven etching, and was patterned with a uniform line width.

As described above, the solar cell of this example also exhibited good characteristics without unnecessary short circuits, shunts, and disconnections.

Test Example 9 An amorphous solar cell was manufactured in the following manner in substantially the same manner as in Test Example 7, except that the configuration of the solar cell was a triple cell type and a microwave CVD method was used to form a semiconductor layer. 300 were produced. First, a lower electrode 202 made of Ag and ZnO is formed on a SUS substrate 201, and then placed in a microwave plasma CVD film forming apparatus (not shown), and an n-layer 203, an i-layer 204, and a p-layer 205 are formed in this order. Was formed. next,
Similarly, a middle layer is formed in the order of the n-layer 213, the i-layer 214, and the p-layer 215, followed by the n-layer 223, the i-layer 224, and the p-layer 2.
A top layer was sequentially formed in the order of 25, and a semiconductor layer was deposited. Next, an ITO film was formed as a transparent conductive film 206 having a function also as an anti-reflection effect as in Test Example 7, and patterning was performed by etching.
00 were produced.

Next, when the initial characteristics were measured in the same procedure as in Test Example 7, the average shunt resistance was 123.0 kΩcm.
^2. Conversion efficiency was 10.4% on average. Test Example 1
When the same observation was made, patterning with a uniform line width was performed without defective unetched portions or uneven etching.

As described above, the triple-cell type solar cell of this example was also good, with no short-circuit, no shunt failure and no disconnection, like the single-cell type solar cell.

(Test Example 10) The heating temperature during the etching treatment was set to 60 ° C, 100 ° C,
Except for 0 ° C. and 300 ° C., 50 single-cell solar cells were produced in the same manner as in Test Example 7, and the initial characteristics were measured and the patterning portion was observed in the same manner as in Test Example 7. Table 3 shows the results.

[0103]

[Table 3]

As shown in Table 3, by adjusting the heating temperature, the characteristics of the completed solar cell change even when the same processing is performed using the same etching paste. In particular, those having a low heating temperature have low values of both the shunt resistance and the conversion efficiency.

Further, the treatment can be carried out in a shorter time by heating to a higher temperature, but it has been found that it is more preferable that the temperature is lower than the melting point of the particles because no paste residue is generated.

Comparative Example 2 After forming a transparent conductive film through the same steps as in Test Example 7, a photosensitive resin resist was applied on the transparent conductive film and dried. Next, in order to form the same pattern as in Test Example 7, a mask was overlaid on the photosensitive resin, and the photosensitive resin was irradiated with ultraviolet light through the mask (exposure). Subsequently, after removing the mask, the photosensitive resin was developed to form a desired resist pattern.

The solar cell substrate on which the resist pattern was formed was immersed in an iron chloride solution for 30 minutes to etch the transparent conductive film, and then sufficiently washed with pure water. After washing, the resist pattern was removed using alcohol, washed again with pure water, and dried.

Subsequently, a collecting electrode was formed on the transparent conductive film in the same manner as in Test Example 7 to complete a single-cell solar cell.

When the initial characteristics of the completed solar cell were measured in the same manner as in Test Example 7, the shunt resistance was 10 kΩcm ^2.
Are 10%, and the conversion efficiency is 5.3 ± 1.8%
And the variation was large. When a patterning line was observed with a microscope although a shunt was generated, the patterning line was in an insufficiently etched state.

This defect is considered to be due to insufficient removal of the unnecessary photosensitive resin during patterning of the photosensitive resin. Some of the low conversion efficiencies have a high series resistance, which is considered to be due to peeling of a part of the semiconductor layer during the liquid treatment.

(Test Example 11) In order to confirm the long-term stability of the etching, the same method as in Test Example 1 was automated, printed 1000 times with a 10-second tact, and patterned in the same manner as in Test Example 1. Thereafter, the same observation and line width measurement as in Test Example 1 were performed on the substrate on which the transparent conductive film was patterned at the 10000th time. As a result, a good pattern was obtained as in Test Example 1.

(Test Example 12) In order to confirm the long-term stability of the etching, after the paste was prepared, and after storing for 60 days, patterning was performed in the same manner as in Test Example 1. When the same observation and measurement of the line width as in Test Example 1 were performed, a good pattern was obtained as in Test Example 1.

Test Example 13 Amorphous solar cell (40) having one pin structure
0) was manufactured using the above-described steps including the patterning step of the present invention.

First, a stainless steel substrate 40 having an SiC layer deposited by DC sputtering as an insulator
1 was prepared, and the substrate was placed in a DC sputtering apparatus (not shown). An aluminum film was deposited on the SiC layer, and a first electrode was formed using an etching paste.

The etching paste was prepared in the same manner as in Test Example 1 except that an etching paste of a mixed solution of phosphoric acid, nitric acid and acetic acid was used. The etching paste was applied on the first electrode layer using a screen printer (not shown) to form a fine pattern.

Next, baking (heat treatment), washing, and drying were performed as described in Test Example 7. Next, a semiconductor layer having an n-type layer, an i-type layer, and a p-type layer in this order was deposited on the first electrode and the substrate as in Test Example 7.

An etching paste having a mixed solution of hydrofluoric acid, nitric acid and acetic acid was printed on the semiconductor layer by a screen printer (not shown) in order to form a fine pattern (groove 405).

Next, after forming the semiconductor, ITO was deposited on the semiconductor and the first electrode to form a second electrode.

Next, an etching paste was prepared in the same manner as in Test Example 1, and was subjected to I-screen printing using a screen printing machine (not shown).
Coated on TO. The groove 407 was formed by patterning using the etching paste.

The initial characteristics of 100 solar cells (series-connected monolithic type) manufactured as described above were measured in the same manner as in Test Example 7.

As a result, the average value of the shunt resistance was 12
At 1.5 kΩcm ² , the average value of the conversion efficiency was 7.8%.

The quality of the etching was visually determined. As a result, no residue could be found in the region to be etched. Further, the etching uniformity was excellent, and the obtained pattern had a uniform line width.

As described above, the solar cell manufactured by using the etching technique of the present invention exhibited excellent characteristics without electrical short circuit and shunt defect. Also, no disconnection of the formed line occurred.

The present invention is not limited to the above-described embodiment, but can be appropriately modified and combined within the scope of the present invention.

The semiconductor element includes a photovoltaic element such as a solar cell, a phototransistor having a transparent conductive film, a photodiode, a photosensor such as a CCD, and the like. An element such as a liquid crystal device having a transparent conductive film deposited on a substrate is also included.

[0126]

As described above, according to the present invention,
It is possible to provide an etching method which requires a small number of processing steps, is simple and has excellent selection accuracy, and a method for manufacturing a semiconductor element having steps utilizing the method.

Further, according to the present invention, the transparent conductive film can be stably etched, the process defect does not occur, and the transparent conductive film can be efficiently etched at low cost. And a method for manufacturing a semiconductor device having a process utilizing the method.

In addition, according to the present invention, there is provided a method of manufacturing a semiconductor device having a process utilizing a method of etching a transparent conductive film which has a high yield and has no short circuit, shunt or poor appearance which may be caused by defective etching. Can be provided.

Further, according to the present invention, it is possible to provide an etching agent having stable characteristics even when stored for a long time.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view illustrating an example of a layer configuration of a solar cell.

FIG. 2 is a schematic cross-sectional view illustrating an example of a layer configuration of a solar cell.

FIG. 3 is a schematic plan view for explaining an example of a top configuration of a solar cell.

FIG. 4 is a schematic cross-sectional view of an object to be processed for explaining an example of an etching process.

FIG. 5 is a schematic cross-sectional view of an object to be processed for explaining an example of an etching process.

FIG. 6 is a schematic plan view of the object shown in FIG.

FIG. 7 is a schematic sectional view of a solar cell (photovoltaic element) serialized using the present invention.

[Explanation of symbols]

 101 glass substrate, 102, 106 transparent conductive film, 103 paste, 104, 207 patterning line, 200, 300 photovoltaic element main body, 201 SUS substrate, 202 lower electrode, 203, 213, 223 n layer, 204, 214 , 224 i-layer, 205, 215, 225 p-layer, 208 grid electrode, 400 photovoltaic device, 401 substrate, 402 first electrode, 403 first groove etched first electrode layer, 404 semiconductor, 405 A second groove obtained by etching the semiconductor layer; 406 a second electrode; and 407 a groove obtained by etching the second electrode layer.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Satoshi Niikura Canon Inc. 3- 30-2 Shimomaruko, Ota-ku, Tokyo (56) References JP-A 1-147078 (JP, A) JP-A 57 -89482 (JP, A) JP-A-2-42766 (JP, A) JP-B-46-37401 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/306, 21/308 C23F 1/00-3/06 H05K 3/06

Claims (13)

(57) [Claims] A step of disposing a paste having fine particles of at least one kind of polymer resin and an etching solution on a material to be etched; A step of performing a heat treatment at a temperature equal to or lower than the melting point. Wherein said polymer resin is an acrylic resin, the manufacture of semiconductor devices according to claim 1 comprising the silicone resin, benzoguanamine resin, fluorine resin, urethane resin, at least one resin selected from the group consisting of polystyrene resin Method. 3. The method according to claim 7, wherein the fine particles have an average particle diameter of 20 μm or less. Wherein said paste comprises printing method, a method of manufacturing a semiconductor device according to claim 1 which is arranged by either coating or dotting method. 5. A method of manufacturing a semiconductor device according to claim 1 wherein the semiconductor device having a non-single-crystal semiconductor layer. 6. The method according to claim 5 , wherein the non-single-crystal semiconductor layer includes an amorphous semiconductor material containing silicon atoms. Wherein said semiconductor element is a photovoltaic element, a photosensor, a method of manufacturing a semiconductor device according to claim 1 which is one selected from the liquid crystal device. 8. The method according to claim 1, wherein the material to be etched is a transparent conductive film. 9. The method according to claim 1 material to be the etching is a metal. 10. The paste material has a size of 10 μm or more and 2 mm or more.
The method for manufacturing a semiconductor device according to claim 1 , wherein the semiconductor device is arranged to have a thickness of less than. 11. The method according to claim 1 having the paste was further glycerine. 12. The method of claim 1, having the semiconductor element is a p-type semiconductor layer, an i-type semiconductor layer and n-type semiconductor layer in this order
3. The method for manufacturing a semiconductor device according to item 1. 13. The method according to claim 1 comprising the step of washing away the paste was after the thermal treatment process.