JP4170429B2 - Method for forming thin film solar cell pattern - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a patterning process for a thin film solar cell. With the spread of solar cells, there is an increasing demand for cost reduction of solar cells. For this reason, reduction of the production cost of the cell patterning which is one of the thin film solar cell production processes is important. Thin film solar cell patterning methods include laser patterning, chemical etching, and the like, all of which have high production costs.
In contrast, in the present invention, a pattern is formed by using magnetic fluid ink, and a thin film is grown, so that a series of patterns can be easily changed by changing the magnetic pattern. However, it is advantageous for reducing the production cost.
[0002]
[Prior art]
Conventionally, a silicon semiconductor has been the mainstream as a semiconductor material constituting a solar cell. However, since many silicon semiconductors in practical use are single crystals, it is difficult to increase the area. Moreover, since it is a single crystal, there are problems such as high cost, high manufacturing costs, and high power generation costs.
On the other hand, a thin film solar cell using amorphous silicon has been attracting attention as a solar cell that has a large absorption coefficient in the visible region and can reduce power generation costs. As the most practical configuration, for example, a first electrode is formed on a substrate, and then a photovoltaic generation layer is formed in the order of n layer, i layer, and p layer or in the order of p layer, i layer, and n layer. Then, the structure which provides a 2nd electrode is taken. As a substrate for these solar cells, a conductive metal material or an insulating substrate such as glass or plastic film can be used.
[0003]
FIG. 1 is a cross-sectional view showing a thin film solar cell pattern manufacturing process according to a conventional method.
First, as shown in FIG. 1A, a substrate 11 such as glass or a plastic film is prepared. Next, in order to form the first electrode on the base material, a metal thin film that becomes the metal electrode layer 12 is formed by vapor deposition, sputtering, or the like (FIG. 1B). The metal material may be any conductive material, and aluminum, copper, chromium, silver or the like is used. In order to form a metal thin film into an electrode pattern shape, a photosensitive resist material is applied on the metal thin film, and pre-baking, mask alignment, photomask exposure, and development processing are performed (FIG. 1C), and post-baking. Then, a resist film 13 is formed. Next, the metal thin film is etched through the resist film (FIG. 1D). Etching is usually chemical etching using ferric chloride or the like, but laser patterning can also be used. Thereafter, when the resist film 13 is peeled off, a metal electrode pattern is formed on the substrate (FIG. 1E).
Usually, a series of steps from application of the resist material to exposure, development, etching, and resist removal is referred to as “patterning”.
[0004]
Next, an amorphous silicon layer 14 is formed on the metal electrode layer 12 by laminating three layers in the order of p-type, i-type, and n-type or in the order of n-type, i-type, and p-type. The amorphous silicon layer is patterned by coating (FIG. 1F). After forming the transparent conductive film 15 to be the upper electrode on the silicon layer, patterning is performed again to form a transparent electrode pattern (FIG. 1G). Finally, a passivation film 16 is formed to complete a thin film solar cell pattern (FIG. 1H).
[0005]
[Problems to be solved by the invention]
As described above, in the manufacturing method by chemical etching of a thin film solar cell according to the conventional method, it is necessary to repeatedly perform “patterning”, which increases the manufacturing cost of the solar cell. The same applies to laser patterning and the like.
As a means for solving this problem, a method of forming a pattern by applying a fluorine-based organic material such as foblin oil on a substrate by a printing method or the like has been proposed by the present applicant (Japanese Patent Application No. Hei 9-187228). issue). The present invention uses a ferrofluid ink in which a ferromagnetic material is mixed with this fluorine-based organic material, particularly perfluoropolyether, to more easily form a ferrofluid ink pattern on a substrate, thereby further improving the process. It was researched to reduce costs.
[0006]
[Means for Solving the Problems]
The first of the gist of the present invention for solving the above problems is a solar cell formed by sequentially forming a first electrode thin film, an amorphous silicon thin film, and a second electrode thin film on one surface of a substrate. A cell pattern forming method comprising: forming a pattern using a magnetic fluid ink in a vacuum on a substrate and / or a thin film formed on the substrate; A method of forming a thin-film solar cell pattern, characterized in that it has at least one film forming step for forming a first or next thin-film pattern in a portion without magnetic fluid ink. Since it is this formation method, a thin film photovoltaic cell pattern can be mass-produced at low cost.
[0007]
The second of the gist of the present invention for solving the above-mentioned problems is that a patterning magnetic substrate on which a pattern is magnetically recorded is arranged on the side opposite to the thin film forming surface of the base material, thereby forming the thin film forming surface of the base material. The method of forming a thin-film solar battery cell pattern is characterized in that a magnetic fluid ink pattern is formed on the side according to the magnetic pattern of the magnetic substrate. Since it is this formation method, a thin film photovoltaic cell pattern can be mass-produced at low cost.
[0008]
The third of the gist of the present invention for solving the above problems is to form a thin film pattern by selectively growing the thin film in a portion without the magnetic fluid ink, so that the first electrode thin film, the amorphous silicon thin film, And a method of forming a thin-film solar battery cell pattern, wherein the film-forming step of the second electrode thin film is continuously performed in a vacuum. Since it is this formation method, a thin film photovoltaic cell pattern can be mass-produced at low cost.
[0009]
The fourth of the gist of the present invention for solving the above-mentioned problem is that after growing the thin film on the entire surface including the portion without the magnetic fluid ink, the unnecessary portion of the thin film is washed with the magnetic fluid ink and selectively removed. The method for forming a thin-film solar battery cell pattern is characterized by forming a thin-film pattern. Since it is this formation method, a thin film photovoltaic cell pattern can be mass-produced at low cost.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
A pattern can be formed by applying a fluorine-based organic material having a low vapor pressure and high heat resistance, for example, foblin oil or the like on a substrate in a vacuum by a printing method or the like.
Fobrin oil is a chemical belonging to perfluoropolyether developed by Audimont (USA: AUSIMINT), and is a chemically stable and inert fully fluorinated oil, that is, liquid fluororesin. . Originally, it is a chemical used in lubricants, sealants and the like.
FIG. 5 shows the chemical structure of foblin oil. FIG. 5A shows a type having a side chain, which is synthesized from hexafluoropropylene (CF ₂ = CF-CF ₃ ) and oxygen. FIG. 5B shows a straight-chain type, which is synthesized from tetrafluoroethylene (CF ₂ = CF ₂ ) and oxygen.
The pattern formation of the fomblin oil can be performed in the air, but it is preferably performed in a vacuum in order to avoid adverse effects such as moisture.
[0011]
After forming a pattern with a fluorine-based organic material, a vacuum thin film is deposited on the pattern using a CVD method, a sputtering method, a vapor deposition method, or the like. Here, the vacuum thin film refers to various thin films such as a metal thin film, an amorphous silicon layer, and a transparent conductive film formed under reduced pressure as described above. In this way, the fluorine organic material is used as a mask (that is, a mask provided on the lower side of the pattern forming material) so that a thin film is selectively deposited avoiding the fluorine organic material portion or on the substrate and the fluorine organic material. A thin film is deposited on the entire surface. In the latter case, the applied fluorinated organic material and the thin film deposited thereon are then selectively removed by dissolving or wiping with a highly fluorinated organic solvent. By these methods, it is possible to form a thin film pattern that requires relatively little accuracy (for example, a line and space of 200 μm or less required for a solar cell), and thereby a thin film solar cell pattern can be formed by a conventional chemical etching method. It becomes possible to form without using.
As such a fluorine-based organic material, a fluorine-based material capable of forming a stable thin film on a substrate, not limited to foblin oil, for example, a stable material such as “KRYTOX 1525” manufactured by DuPont is used. You can also
[0012]
Embodiments of the present invention will be described below.
The present invention is characterized in that a ferromagnetic material is dispersed in a fluorine-based organic material and used as a magnetic fluid ink. When ultrafine particles of a ferromagnetic material are made solvophilic by surface treatment and dispersed in a liquid, a stable colloidal solution in which particles do not aggregate or settle even under a magnetic field or gravitational field can be obtained. This colloidal solution exhibits a unique behavior of being sensitive to a magnetic field as a magnetic liquid. In the present invention, in order to take advantage of the characteristics of such a magnetic fluid, an ultrafine ferromagnetic material is dispersed in a fluorine-based organic material, in particular, the above-mentioned von Buyan oil, to make an ink.
The solvent used in the magnetic fluid ink in the present invention is an organic fluorine compound, and in particular, fomblin oil, which is a linear perfluoropolyether, has excellent characteristics, and it is a raw liquid that is not diluted with other solvents. It is preferable to use it.
[0013]
Examples of the ferromagnetic substance include ferromagnetic iron oxide (magnetite) powder, magnetic oxides such as manganese ferrite and cobalt ferrite, magnetic metal such as iron and cobalt, and powders such as iron nitride, but are easy to manufacture. From this, magnetite powder is preferable. The particle diameter of the magnetic particles is preferably from 200 nm to 5 nm, particularly preferably from 100 nm to 10 nm. If it is less than 3 nm, the particles may not exhibit magnetism.
[0014]
FIG. 2 is a cross-sectional view illustrating a method for forming a thin-film solar cell pattern according to the present invention. As shown in FIG. 2, the present invention employs a mask film forming method in which a ferrofluid ink pattern is disposed on a substrate at a place where a thin film is not desired to be deposited or a place where the thin film is removed, and then the thin film is grown. Yes.
First, as shown in FIG. 2A, magnetic fluid ink made of a fluorine-based organic material is arranged in a pattern on a substrate 21 such as glass or plastic. The arrangement of the magnetic fluid ink pattern is controlled by a magnetic substrate 20 for patterning disposed on the side opposite to the thin film forming surface of the base material 21 and the magnetic lines of force of the magnetic pattern 20a of the magnetic substrate 20 for patterning. FIG. 2A shows a situation in which a magnetic fluid ink pattern 22a for forming a metal thin layer to be the first electrode is formed on the base material 21.
In the case of magnetic fluids made of fluorine-based organic materials, especially perfluoropolyether, the vapor pressure is very low, so there is no curing due to drying or aggregation of magnetic particles, and it is stable. The same magnetic fluid ink can be used repeatedly.
[0015]
Thereafter, a thin metal layer 23 serving as a first electrode is formed on the entire surface of the base material 21 by selective growth by vapor deposition, CVD, or sputtering (FIG. 2B).
In general, when a fluorine-based organic material is used, a thin film is deposited on the entire substrate including the magnetic fluid ink by sputtering, but no thin film is deposited on the magnetic fluid ink by the CVD method or the vapor deposition method. Therefore, when a thin film is deposited on the entire surface of the substrate by sputtering, it is necessary to selectively remove the thin film portion deposited on the magnetic fluid ink portion together with the magnetic fluid ink to form a pattern. On the other hand, in the case of the CVD method or the vapor deposition method, a thin film is selectively formed avoiding the magnetic fluid ink portion. Therefore, if the magnetic fluid ink is moved, a thin film pattern is formed. Therefore, no special operation such as etching is required. In the case of the present invention, it is preferable to perform selective growth from the viewpoint of repeated use of magnetic fluid, but pattern formation can be facilitated even in the case of selective removal. FIG. 2 illustrates the case of selective growth.
[0016]
When the magnetic fluid ink on the substrate is selectively removed, the fluorine-based organic can be removed by means such as ultrasonic cleaning performed by immersing the base material in a highly fluorinated organic solvent, or dissolution or wiping by applying an organic solvent. Remove material. At this time, a crack portion is generated in the thin film caused by vibration by ultrasonic waves or pressure by wiping, and thereby the organic solvent enters the thin film from the crack portion and removes the fluorine-based organic material. As the highly fluorinated organic solvent, a low molecular product of a fluorine-based organic material can be used.
After cleaning, only the portion directly deposited on the base material of the thin metal layer deposited on the entire surface of the substrate remains in a pattern to form an electrode pattern. Fobrin oil as a fluorinated organic material is soluble in highly fluorinated organic solvents, such as Freon 113, perfluorooctane, and low molecular weight products of Fobrin oil ("Galden" manufactured by AUDIMONT). It is almost incompatible with other water, organic solvents, and fats.
[0017]
Next, the magnetic fluid ink 22b made of a fluorine-based organic material is again arranged in a pattern by the patterning magnetic substrate 20 in a portion other than the electrode pattern, where the amorphous silicon layer is not formed or where the thin film is selectively removed. To do. The change to the magnetic pattern 20b may be performed by rewriting the magnetic recording on the patterning magnetic substrate, or by preparing the patterning magnetic substrate 20 on which a plurality of different magnetic patterns are formed in advance and replacing the substrate. Good. In FIG. 2, the left-pointing arrow means that the patterning magnetic substrate is replaced.
[0018]
Three layers (n-type layer, i-type layer, and p-type layer) of amorphous silicon layer 24 are sequentially deposited on the base material, that is, on the exposed portion of the electrode pattern and base material by CVD or the like (FIG. 2C )). Since the three amorphous silicon layers only have to have substantially the same shape, they can be deposited by one arrangement of the magnetic fluid pattern 22b. In the case of the CVD method, selective growth is performed in which an amorphous silicon layer is not formed on the magnetic fluid pattern. In FIG. 2C, the amorphous silicon layer 24 is illustrated as a single layer, but actually, the three layers are laminated.
[0019]
Various methods are known for the formation of an amorphous silicon layer. The most frequently used method is to introduce a silane gas (SiH ₄ ) into a vacuum furnace, apply an electric field, and perform plasma discharge to form an amorphous silicon thin film on the substrate. It is a method of forming. At this time, when no impurity is added to the silane gas, the i-type layer can form a p-type layer when diborane (B ₂ H ₆ ) is added as an impurity, and an n-type layer when phosphine (PH ₃ ) is added. . That is, the junction of the n · i · p layer can be formed by switching the gas. As described above, the n, i, and p types can be formed by one reaction layer only by switching the gas, but can also be continuously formed by a line that is performed in a reaction chamber in which each layer is separated. In this case, there is an effect that the residual impurities are less adversely affected. As a result, the amorphous silicon layer deposited on the portion other than the magnetic fluid pattern 22b made of the fluorine-based organic material remains in a pattern to form an amorphous silicon layer 24 (FIG. 2C).
[0020]
Subsequently, in order to form the second electrode pattern with a transparent conductive film, the magnetic fluid ink pattern 22c is again patterned on the part where the electrode pattern is not formed or the part where it is selectively removed using the patterning magnetic substrate 20. Arrange in a shape. The portion where the magnetic fluid ink is disposed forms an insulating portion between the second electrode patterns. After the transparent conductive film 25 is formed on the entire surface of the amorphous silicon layer and the exposed portion of the base material, the portion where the magnetic fluid ink is disposed (FIG. 2D), in the case of selective growth, In the case of selective removal, the transparent conductive film on the magnetic fluid ink is removed by removing the magnetic fluid ink by means such as ultrasonic cleaning immersed in a highly fluorinated organic solvent, dissolution by application, wiping, etc. A second electrode pattern made of the transparent conductive film 25 is formed on the substrate (FIG. 2E).
Materials used for the transparent conductive film include In ₂ O ₃ , SnO ₂ , In ₂ O ₂ —SnO ₂ (ITO), and TiO ₂ , and these can be used for sputtering, electron beam evaporation, resistance heating evaporation, ion plating, etc. Can be formed.
[0021]
Finally, a passivation film 26 is formed on the entire surface by a vacuum film formation method using CVD or the like, thereby completing a thin film solar battery cell pattern (FIG. 2F). As the passivation film material, Si ₃ N ₄ , SiO ₂ or the like is preferably used, but it may be a coating film of a polymer resin such as a transparent fluororesin paint or a fluoride polymer having excellent weather resistance.
[0022]
Various materials other than glass can be used as the base material 21 of the thin film solar cell. For example, a resin film such as polyimide, polyester, polyethylene terephthalate, epoxy, polyacrylate, polyarylate may be used. Further, a conductive material can also be used as the first electrode. In this case, stainless steel, aluminum, copper, titanium, galvanized steel sheet, carbon sheet, etc. can be used.
[0023]
In the above processes, all are performed by a pattern forming method in which magnetic fluid ink made of a fluorine-based organic material is disposed, but other pattern forming methods can be used in combination. For example, the pattern formation of the first electrode pattern and the amorphous silicon layer is performed by the pattern formation method of the present invention using magnetic fluid ink, and the formation of the second electrode pattern is performed by a sputtering method or a vapor deposition method using a resist mask. For example. In particular, the vapor deposition method is easy to use together because the film forming pressure is lower than that of the CVD method. It is also free to combine selective growth and film formation by selective removal.
[0024]
FIG. 3 is a cross-sectional view showing a thin-film solar battery cell pattern formed by the forming method of the present invention. The structure or performance of the thin film solar cell according to the forming method of the present invention is not different from that according to the conventional chemical etching pattern forming method. The one shown is a p-i-n type in which two unit cell patterns are joined in series and receive sunlight (arrows) from the transparent conductive film 25 side. A voltage can be obtained. Moreover, it can also be set as a thing of a large current by connecting the unit cell pattern in parallel. Further, the formation order of the amorphous silicon layer 24 can be changed to provide an n.i.p type solar cell. Although the current obtained by such a solar cell is a direct current, it can be converted by an inverter into a household AC power source.
[0025]
FIG. 4 is a diagram showing an amorphous silicon layer. This portion is a photovoltaic layer, and an n-type amorphous silicon layer 24n, an i-type amorphous silicon layer 24i, and a p-type amorphous silicon layer 24p are stacked from the substrate side. Sunlight passes through the transparent conductive film and photons are absorbed to form a pair of electrons and holes. However, since the electric field existing inside the silicon substrate moves electrons to n-type and holes to p-type, n Current flows from the mold to the p-type. This current is taken out and used.
[0026]
【Example】
An embodiment of the present invention will be described below with reference to FIG.
(1) <Preparation of magnetic fluid ink>
A magnetic fluid ink was prepared by dispersing 100 g of iron oxide (magnetite powder) having a particle diameter of 20 nm in a stock solution of linear perfluoropolyether [average molecular weight 7250] (“foblinyr 1800” manufactured by Augmont). At this time, 10 g of sodium oleate was added as an additive to improve dispersibility, and the mixture was stirred for 3 hours with red devil.
The obtained magnetic fluid ink had a kinematic viscosity at 20 ° C. of 500 cps, and showed a characteristic of flowing sharply with respect to the magnetic field lines.
[0027]
(2) <Preparation of patterning magnetic substrate>
Magnetic recording was performed on a magnetic tape for audio having a width of 10 cm (“MA (metal tape)” manufactured by TDK Corporation) with a magnetic head. As for the magnetic substrate 20 for patterning, magnetic output is obtained in the region where the respective thin film patterns are not formed for the three types of the lower electrode pattern 20a, the amorphous silicon layer pattern 20b, and the upper transparent electrode pattern 20c on the solar cell substrate side. Formed and prepared.
When the output of this patterning magnetic substrate was measured through a glass substrate having a thickness of 1.1 mm, an output of 80 Gauss was obtained at the magnetic recording portion.
[0028]
(3) <Formation of first electrode pattern>
A clean transparent glass substrate (Corning “# 1737”) thickness: 1.1 mm, size 10 cm □ was prepared, and the magnetic fluid ink 22 prepared in the above (1) was applied onto the substrate 21 using a roll coater. And applied. The coating amount is such that the magnetic fluid ink film 22a having a thickness of about 100 μm is formed in the area of the average value [about 10 cm ² ] of the area of the lower electrode pattern, the amorphous silicon layer pattern, and the thin film pattern non-formation area of the upper electrode pattern. In such a manner, a pre-calculated amount [about 0.1 cm ³ ] was applied.
Next, when the patterning magnetic substrate 20 for the first electrode pattern prepared in (2) was brought into close contact with the back surface of the transparent glass substrate 21, the magnetic fluid ink flowed according to the magnetic pattern to form a pattern.
[0029]
After the magnetic fluid ink pattern is formed, the base material 21 is introduced into the sputtering apparatus with the magnetic substrate for patterning in close contact, and a film is formed using Cr as a target (FIG. 2B). Then, a Cr thin film 23 was selectively grown.
The sputtering conditions are as follows.
(Sputtering conditions)
Target: Cr (Purity: 99.99%)
Deposition temperature: 350 ° C
Deposition pressure: 5 mTorr
DC power: 2.5kW
Ar flow rate: 100scm
Deposition rate: 20cm / sec
Film thickness: 50nm
[0030]
(4) <Amorphous silicon layer formation>
When the patterning magnetic substrate 20 arranged on the back surface of the cell base material is switched to the amorphous silicon layer pattern 20b, the magnetic fluid ink 22 is dragged along with the movement of the magnetic pattern to form a new pattern 22b.
The same magnetic fluid ink pattern was used, and three amorphous silicon layers 24 were selectively deposited on portions other than the magnetic fluid ink pattern.
[0031]
Subsequently, the base material was introduced into a vacuum reactor, and an amorphous silicon layer 24 was formed by a CVD method (FIG. 2C). In this step, after (1) an n-type amorphous silicon layer [a-Si: H (n) layer] is first formed from the substrate side, (2) a non-doped i-type amorphous silicon layer [a-Si: H (i) layer] was formed, and finally, (3) a p-type amorphous silicon layer [a-Si: H (p) layer] was formed.
For the n-type of (1), an offline silicon wafer is crushed and 3% by weight of phosphorus (P) is used. For the p-type of (3), the silicon wafer is also crushed, What doped 10 weight% of boron (B) was used.
[0032]
Each film forming condition is as follows.
(1) (P-doped a-Si: H (n layer) film forming conditions)
Deposition temperature: 300 ° C
a-Si: H / H ₂ / PH ₃ flow rate = 10/30/10 sccm
Deposition pressure: 50 mTorr
RF power: 50W
Deposition rate: 10cm / sec
Film thickness: 500mm
(2) (a-Si: H (i layer) film forming conditions)
Deposition temperature: 300 ° C
a-Si: H / H ₂ flow rate = 10/50 sccm
Deposition pressure: 50 mTorr
RF power: 50W
Deposition rate: 10cm / sec
Film thickness: 3000mm
(3) (B ₂ H ₆ doped a-Si: H (p layer) film forming conditions)
Deposition temperature: 300 ° C
a-Si: H / H ₂ flow rate / B ₂ H ₆ = 10/30/5 sccm
Deposition pressure: 50 mTorr
RF power: 50W
Deposition rate: 10cm / sec
Film thickness: 300mm
[0033]
(5) <Transparent electrode pattern formation>
When the patterning magnetic substrate 20 disposed on the back surface of the cell base material is switched to the transparent electrode pattern 20c, the magnetic fluid ink 22 is dragged along with the movement of the magnetic pattern to form a new magnetic fluid ink pattern 22c. .
[0034]
A transparent conductive layer 25 made of ITO was formed on the portion other than the magnetic fluid ink pattern 22c (including the exposed portion of the base material) by the reactive sputtering method under the following conditions (FIG. 2D).
(Sputtering conditions)
Target: In ₂ O ₃ —SnO ₂ sintered target (SnO ₂ : 10 wt%)
Deposition temperature: 250 ° C
Deposition pressure: 5 mTorr
DC power: 2.0kW
Ar / O ₂ flow rate: 100/3 sccm
Deposition rate: 10cm / sec
Film thickness: 1000mm
[0035]
The base material after film formation was dipped in a foblin remover (Audimont “Galden”) and washed with an ultrasonic cleaner (output 100 W, 39 KHz, 3 minutes) to be applied onto the base material. The magnetic fluid ink 22c was dissolved and removed, and only the transparent conductive film layer formed on the base glass and the amorphous silicon layer remained to form the upper electrode (FIG. 2E). In addition, since the transparent conductive film 25 and the first electrode 23 are connected at a portion indicated by “=” in FIG. 2G, a single cell is formed in a continuous cell joined in series. Become.
[0036]
<6><Formation of Passivation Film>
Finally, an SN _X film was formed as a passivation film 26 by a vacuum film forming method using CVD, thereby completing a thin film solar cell (FIG. 2F). Since the passivation film 26 is formed on the entire surface, the magnetic fluid ink 22 was not used. The film forming conditions are as follows.
(SN _X film formation conditions)
Deposition temperature: 250 ° C
a-Si: H / N ₂ flow rate / NH ₃ = 30/500/50 sccm
Deposition pressure: 30 mTorr
RF power: 250W
Deposition rate: 25kg / sec
Film thickness: 500mm
[0037]
When the thin film solar cell produced above was irradiated with AM-1 (a standard light source reproducing the solar radiation spectrum on the equator), the solar cell conversion efficiency in the initial stage was about 8%.
[0038]
【The invention's effect】
Since the method for forming a thin-film solar battery pattern of the present invention uses magnetic fluid ink, it is possible to easily form a thin film by repeatedly using several types of mask patterns. In particular, when a thin film is selectively grown while avoiding the magnetic fluid portion, the cell pattern can be formed because the magnetic fluid pattern formation and thin film pattern formation operations can be repeated in the same or continuous vacuum apparatus. This can be done efficiently, and the capital investment, production cost, and yield can be improved, and the cost of solar cells can be reduced.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a thin film solar cell pattern manufacturing process according to a conventional method.
FIG. 2 is a cross-sectional view illustrating a method for forming a thin-film photovoltaic cell pattern according to the present invention.
FIG. 3 is a cross-sectional view showing a thin-film photovoltaic cell pattern formed by the forming method of the present invention.
FIG. 4 is a diagram showing an amorphous silicon layer.
FIG. 5 shows the chemical structure of foblin oil.
[Explanation of symbols]
11, 21 Base material 12, 23 Metal electrode layer 13 Resist film 14, 24 Amorphous silicon layer 15, 25 Transparent conductive film 16, 26 Passivation film 20 Magnetic substrate for patterning 20a, 20b, 20c Magnetic pattern 22 Magnetic fluid ink 22a, 22b 22c Magnetic fluid ink pattern

Claims (8)

A method for forming a solar cell pattern, in which a first electrode thin film, an amorphous silicon thin film, and a second electrode thin film are sequentially formed on one surface of a substrate,
After forming a pattern using a ferrofluid ink in a vacuum on a substrate and / or a thin film formed on the substrate, the first or A method for forming a thin-film photovoltaic cell pattern, comprising at least one film-forming step for forming the next thin-film pattern . On the opposite side with a thin film forming surface of the substrate, by disposing the magnetic substrate patterning magnetically pattern is recorded, the film forming surface of the substrate, the magnetic fluid according to the magnetic pattern of the magnetic substrate 2. The method for forming a thin-film solar cell pattern according to claim 1 , wherein an ink pattern is formed . By selectively growing the thin film on the part without the magnetic fluid ink, by forming the thin film pattern,
3. The thin film solar cell pattern according to claim 1, wherein the first electrode thin film, the amorphous silicon thin film, and the second electrode thin film are continuously formed in a vacuum. Forming method. After a thin film is grown on the entire surface including even part without magnetic fluid ink, by selectively removing the unnecessary portion of the thin film was washed with magnetic fluid ink, according to claim 1, characterized in that to form a thin film pattern And a method for forming a thin-film photovoltaic cell pattern according to claim 2 .   5. The method for forming a thin-film solar cell pattern according to claim 1, wherein the magnetic fluid ink is obtained by dispersing ferromagnetic fine particles in a fluorine-based organic material.   6. The method for forming a thin-film solar cell pattern according to claim 5, wherein the fluorine-based organic material is a side chain type or a linear type perfluoropolyether. 3. The thin film solar cell according to claim 2, wherein the pattern of the magnetic fluid ink is changed by changing the magnetic recording contents of the patterning magnetic substrate or by replacing the magnetic recording contents with a different patterning magnetic substrate. Pattern formation method. 5. The method for forming a thin-film solar cell pattern according to claim 4, wherein the cleaning is performed using a low-molecular high-fluorination organic solvent.

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