KR20100062096A - Solar cell wafer detergent composition - Google Patents

Abstract

PURPOSE: A solar cell wafer detergent composition is provided to have excellent detergency for each cut wafer and to obtain superior cleaning effect by preventing the generation of wafer etching due to washed residue. CONSTITUTION: A solar cell wafer detergent composition includes one or a mixture which is selected from a group comprising glycol ether compound, alcohol compound, and a surfactant. The surface tension of the detergent composition is 20~60 dyne/cm. The glycol ether compound is the glycol ether compound or a mixture which is marked as a chemical formula 1 or a chemical formula 2. The chemical formula 1 is C_6H_5-CH_2O-(CH_2CH_2O)_m(CH_2CHCH_3O)_n-H. The chemical formula 2 is R-O-(CH_2CH_2O)_m(CH_2CHCH_3O)n-H.

Description

Solar cell wafer detergent composition

The present invention relates to a wafer cleaner composition for solar cells. More specifically, in the manufacturing process of the solar cell wafer, the ingot for manufacturing the solar cell wafer is attached to the beam, and then the cutting oil is supplied to perform the cutting process, and thereafter, the cleaning is performed while the cut wafer is attached to the beam. It is to provide a solar cell wafer cleaning composition which can improve cleaning power of each wafer that has been cut and prevent wafer etching by cleaning residues, thereby obtaining an excellent quality cleaning effect.

In the past, silicon wafers were mainly used in semiconductors, but recently, new technology developments and industrial developments have been used in various electronic devices such as solar cells and LEDs, and thus their use ranges are widening.

Wafers can be obtained by cutting silicon ingots. Ingots are obtained by growing silicon crystals, which take from a week to a month, depending on size, quality and specifications. More than about 75% of all single crystal wafers are produced by Czochralski (CZ) method, which uses pure polycrystalline silicon agglomerates. These agglomerates are placed in a quartz crucible and then impart the desired electrical properties to the silicon ingot through the addition of small amounts of Group 3 or Group 5 elements (dopants). The most commonly used dopants are boron, phosphorus, arsenic, and antimony. Depending on which dopant is used, the ingot becomes P-Type or N-Type after growth.

The polysilicon is heated and melted to about 1420 ℃ or higher, which is the melting point in the quartz crucible, and once the polysilicon and the dopant are melted to become liquid, the surface of the melt has a single crystal seed having the same crystal direction as the desired crystal direction. Touch the center part. The seed and quartz crucible are rotated in opposite directions to obtain a uniform diffusion of dopant in silicon. When the conditions for crystal growth are prepared, the seed is lifted little by little to start the growth process. The growth process goes through a speed adjustment process to obtain the desired diameter, and then proceeds at a constant pulling speed.

Once the growth process is complete and the silicon ingot is completed, the wafer is cut to obtain a wafer. In the cutting process, in order to attach the manufactured crystalline ingot to the beam, the ingot is generally attached to the beam using a plastic or curable polymer, and the cutting process is performed. After cutting the ingot, the cutting oil generated in the cutting process And a cleaning process for removing the slurry.

In the cleaning step, there are a sheet of ingots that have been cut from a beam with an ingot, that is, a step of separating and cleaning a wafer or a method of cleaning the entire ingot that has been cut. When the cleaning process is performed by separating the wafer from the beam, that is, the ingot sheet, in which the double cutting process is completed, there is a problem that the yield may be reduced due to damage or other contamination of the wafer during the intermediate handling process.

In order to solve such a problem, the process of cleaning the whole ingot which the cutting process was performed in recent years is applied a lot. However, even in this case, the gap between the wafer and the wafer is very narrow, making it difficult to clean the source of cutting oil and wafer fragments caused by the cutting process, and the wafer is etched by the cleaning agent remaining between the very narrow wafers after cleaning. There is a problem that occurs.

Therefore, the problem to be solved by the present invention is to attach the ingot for manufacturing a solar cell wafer to the beam in the manufacturing process of the solar cell wafer, and then supply the cutting oil to proceed with the cutting process, and then in the state of attaching the cut wafer to the beam When cleaning is performed, it is to provide a wafer cleaning composition for a solar cell that can improve cleaning power for each of the cut wafers and prevent wafer etching due to cleaning residues, thereby obtaining an excellent quality cleaning effect.

In order to solve the above problems, the cleaning composition used in the cleaning process of the wafer cut in the wafer manufacturing process for solar cells according to the present invention is any one selected from the group consisting of a glycol ether compound, an alcohol compound and a surfactant or two kinds thereof. It contains a mixture of the above, the surface tension of the cleaning composition is characterized in that 20 to 60 dyne / cm. The wafer cleaning composition of the present invention has a specific range of surface tension, and thus has an excellent cleaning effect against fine gaps between the wafers attached to the beam after cutting, and effectively removes cleaning components in the washing process after the cleaning is completed. Surface etching can be prevented.

Specific examples of the glycol ether compound included in the wafer cleaner composition for a solar cell of the present invention may include, but are not limited to, a glycol ether compound represented by Formula 1 or Formula 2, or a mixture thereof:

C ₆ H ₅ -CH ₂ O- (CH ₂ CH ₂ O) _m (CH ₂ CHCH ₃ O) _n -H

RO- (CH ₂ CH ₂ O) _m (CH ₂ CHCH ₃ O) _n -H

In Formula 1 and Formula 2, m is an integer of 0 to 20, n is an integer of 0 to 20, R is alkyl of 1 to 16 carbon atoms. The content of the glycol ether compound may be 5 to 80% by weight based on the total weight of the composition, but is not limited thereto.

In addition, the wafer cleaner composition of the present invention may include an alcohol compound, in which case the content may be 1 to 80% by weight based on the total weight of the composition, but is not limited thereto.

In addition, the wafer cleaner composition of the present invention may include 0.1 to 50% by weight of surfactant based on the total weight of the cleaner composition.

In addition, the wafer cleaner composition of the present invention may also be selected from the group consisting of organic acids, inorganic acids or mixtures thereof to improve cleaning power; Or organic bases, inorganic bases or mixtures thereof. In this case, each content may be 0.1 to 50% by weight relative to the total weight of the composition, but is not limited thereto.

In the wafer cleaner composition according to the present invention, the solar cell wafer manufacturing ingot is attached to a beam in a manufacturing process of a solar cell wafer, and then a cutting process is performed. The cleaning power is excellent for each of the prepared wafers, and an excellent quality cleaning effect can be provided by preventing wafer etching by cleaning residues.

Hereinafter, the present invention will be described in detail. The terms or words used in this specification and claims are not to be construed as limiting in their usual or dictionary meanings, and the inventors may appropriately define the concept of terms in order to best explain their invention in the best way possible. It should be interpreted as meaning and concept corresponding to the technical idea of the present invention based on the principle that the present invention.

The wafer cleaner composition of the present invention not only includes any one or a mixture of two or more thereof selected from the group consisting of glycol ether compounds, alcohol compounds and surfactants, but also exhibits excellent cleaning power and cleaning effects and is effective for removing effective cleaning components. As described above, the surface tension is characterized in that 20 ~ 60 dyne / cm. If the surface tension is more than 60 dyne / cm, there is a problem that it is difficult to achieve a sufficient cleaning effect because it is not easy to penetrate the narrow gap between wafers. In addition, when a detergent having a surface tension of more than 60 dyne / cm is present between the wafer and the wafer during washing after washing, the adhesive force between the wafers increases, so that washing is not easy, and thus, the wafer may be etched by the remaining cleaner. . If the surface tension is less than 20 dyne / cm there is no problem of cleaning power and etching, but there are disadvantages economically unreasonable to implement.

In the solar cell wafer cleaner composition of the present invention, the glycol ether compound represented by Chemical Formula 1 or Chemical Formula 2 is a water-soluble solvent, and the surface tension of the cleaning composition is used to clean the wafer, which is a sheet of an ingot attached to a beam. By lowering the cleaning power of the contaminated cutting oil or slurry in all processes to improve the rinsing power by the water in the washing process to prevent etching by the cleaning agent.

Specifically, representative examples of the glycol ether compound represented by Formula 1 or Formula 2 include mono ethylene glycol monobenzyl ether, diethylene glycol mono benzyl ether, triethylene glycol mono benzyl ether, tetraethylene glycol mono benzyl ether, penta ethylene glycol Monobenzyl ether, diethylene glycol monomethyl ether, triethylene glycol monomethyl ether, tetraethylene glycol monomethyl ether, diethylene glycol monoethyl ether, triethylene glycol monoethyl ether, tetraethylene glycol monoethyl ether, diethylene glycol mono Propyl ether, triethylene glycol mono propyl ether, tetra ethylene glycol mono propyl ether, diethylene glycol mono butyl ether, triethylene glycol mono butyl ether, tetra ethylene glycol mono Butyl ether, propylene glycol mono methyl ether, propylene glycol mono butyl ether, dipropylene glycol mono butyl ether, dipropylene glycol mono methyl ether or tripropylene glycol mono methyl ether, and the like, each of which may be used alone or in combination of two or more thereof. Can be.

The glycol ether compound according to the present invention may be included in an amount of 5 to 80% by weight based on the total weight of the wafer cleaner composition for solar cells. If the content is less than 5% by weight, there is a problem that the effect of lowering the surface tension is insufficient, which may cause deterioration of cleaning power and etching, and when the content is more than 80% by weight, there is no further performance improvement effect, which is economically disadvantageous.

In the solar cell wafer cleaning composition of the present invention, the alcohol compound functions to lower the surface tension. The alcohol compound may use conventional monohydric, dihydric, polyhydric alcohols, which are more suitable in terms of workability and effectiveness. Therefore, in the present invention, the alcohol compound may be, for example, monohydric alcohol, preferably dihydric alcohol, and more preferably trihydric alcohol.

As a more specific example, ethanol, methanol, propanol, butanol, isopropanol, ethylene glycol, diethylene glycol, propylene glycol, glycerin, sorbitol, polyethylene glycol, etc. may be used alone or in combination of two or more, but is not limited thereto. . The alcohol compound according to the present invention may be included in an amount of 1 to 80% by weight based on the total weight of the solar cell wafer cleaner. If the content is less than 1% by weight, the effect of lowering the surface tension is insignificant, and if it is more than 80% by weight, there is no further performance improvement effect, which is economically disadvantageous.

The wafer cleaner composition for solar cells of the present invention includes a surfactant for improving cleaning power and improving rinsing power in a washing process by lowering the surface tension of the cleaning agent. The surfactant used in the present invention may be used without limitation to general surfactants, for example, anionic surfactants, cationic surfactants, nonionic surfactants, amphoteric surfactants, etc., each alone or two or more kinds. It may be used in combination, but is not limited thereto.

The surfactant may be included in an amount of 0.1 to 50% by weight based on the total weight of the solar cell wafer cleaner composition. If the content is less than 0.1% by weight, there is no effect of preventing etching through the improvement of the cleaning power and the rinsing power in the washing process, and if the content is more than 50% by weight, there is no further performance improvement effect, which is economically disadvantageous.

Optionally, the wafer cleaner composition for solar cells of the present invention may further include an organic acid, an inorganic acid or a mixture thereof to more effectively perform the cleaning of the inorganic particles generated during the cutting of the ingot.

The organic acid and / or inorganic acid may be used without limitation to conventional organic acid and / or inorganic acid. Preferably, a weak acid with less off-flavor in terms of off-flavor and workability can be used. Specifically, citric acid, gluconic acid, propanoic acid, malonic acid, phthalic acid, carboxylic acid, carbonic acid, hydrofluoric acid, hypophosphoric acid and the like may be used alone or in combination of two or more, but is not limited thereto.

Organic acid, inorganic acid or a mixture thereof according to the present invention may be included in an amount of 0.1 to 50% by weight based on the total weight of the detergent composition, more preferably 0.5 to 40% by weight. If it is less than 0.1% by weight does not exert an effect on improving the cleaning power, if it exceeds 50% by weight there is no further performance improvement effect is economically disadvantageous.

Optionally, the wafer cleaner composition for solar cells of the present invention may further include an organic base, an inorganic base or a mixture thereof to more effectively perform the cleaning of the inorganic particles generated during the cutting of the ingot.

The organic base and / or inorganic base may be used without limitation to conventional organic base and / or inorganic base. Specifically, as the inorganic base, potassium hydroxide, sodium hydroxide, sodium silicate, potassium phosphate, sodium phosphate, potassium carbonate, sodium carbonate, sodium gluconate, ethylenediaminetetraacetic acid, etc. may be used alone or in combination of two or more thereof. ; As the organic base, monoethanolamine, diethanolamine, triethanolamine, morpholine, tetramethylammonium hydroxide, tetraethylammonium hydroxide, or the like may be used alone or in combination of two or more thereof.

Organic base, inorganic base or a mixture thereof according to the present invention may be included in an amount of 0.1 to 50% by weight relative to the total weight of the solar cell wafer cleaning composition, more preferably 0.5 to 40% by weight. If it is less than 0.1% by weight does not exert an effect on improving the cleaning power, if it exceeds 50% by weight there is no further performance improvement effect and economically disadvantageous.

In addition, in the wafer cleaner composition of the present invention, a residual amount of water may be included as an additional solvent.

Hereinafter, the present invention will be described in detail with reference to Examples. However, embodiments according to the present invention can be modified in many different forms, the scope of the present invention should not be construed as limited to the embodiments described below. The embodiments of the present invention are provided to more completely explain the present invention to those skilled in the art.

Examples 1-7 and Comparative Examples 1-3

The components of each content shown in Table 1 below were stirred at room temperature until they became a transparent liquid to prepare a wafer cleaner composition.

Glycol ether compounds Alcohol Surfactants mountain base water Diethylene glycol monobutyl ether Triethylene glycol monopropyl ether Polyethylene glycol Alkyl polyglucoside (C12 ~ 14) Sodium Lauryl Ethylene Sulfate Gluconic Acid Potassium hydroxide Tetramethylammonium hydroxide Example One 30 - - - - - 5 - 65 2 - 40 - - - - - 5 55 3 - - 40 - - 10 - - 50 4 - - - 10 - - - 5 85 5 10 - - - 5 - - - 85 6 10 - - 5 - - 2 - 83 7 10 - - 5 - 2 - - 83 Comparative example One - - - - - - 10 - 90 2 - - - - - 10 - - 90 3 2 - - - - - - 10 88

Test Example

In the solar cell wafer cleaning process, the cleaning agent is used at a concentration of 1 to 5% by weight, and the cleaning process is performed by spraying, ultrasonic or simple deposition at a temperature of 25 to 60 degrees. In the present invention, the wafer cleaner compositions prepared in Examples 1 to 7 and Comparative Examples 1 to 3 are diluted to 5% by weight in water to bring the temperature to 40 ° C., and the wafer is immersed in this solution for 10 minutes to irradiate with ultrasonic waves. Was carried out. After cleaning, the wafer was rinsed with distilled water at room temperature and then dried to evaluate the cleaning power of the wafer and to examine whether the wafer was etched after cleaning. In addition, the surface tension of the 5% by weight dilution solution of the wafer cleaner compositions prepared in Examples 1 to 7 and Comparative Examples 1 to 3 was measured, and the results are shown in Table 2 below.

Surface tension

The 2% dilution solution of the composition was measured using a surface tension meter (Model: Tensiometer K100, manufacturer: KRUSS).

2. Cleaning power

Contaminated specimens were prepared by applying a cutting oil and a mixture of inorganic contaminants (polishing agent and wafer chips) generated after cutting the wafer and drying at 80 ° C. for 5 hours. The contaminated specimens were fixed by arranging 10 sheets vertically at 0.2 mm intervals, and then immersed in the composition, sonicated at 40 ° C for 10 minutes, rinsed three times with water, and the degree of contaminants remaining on the wafer surface was expressed as follows.

◎: Pollutant remains within 5% of total area

○: Pollutant remains within 5-15% of total area

△: pollutant remains within 15-25% of the total area

×: Pollutant remains more than 25% of total area

3. Etching

After cleaning, the presence or absence of etching on the wafer surface was visually determined.

Surface tension (dyne / cm) Cleaning power Etching Example One 52 ◎ none 2 58 ◎ none 3 58 ○ none 4 28 ◎ none 5 28 ○ none 6 27 ◎ none 7 29 ◎ none Comparative example One 72 × Occur 2 72 × none 3 70 △ Occur

As shown in Table 2, the wafer cleaner compositions of Examples 1 to 7 according to the present invention have a low surface tension of 60 dyne / cm or less of the wafer compared to Comparative Examples 1 to 3, and have excellent cleaning power and concern of etching. You can see that there is no. In Comparative Examples 1 and 3, the wafer is etched, and in Comparative Example 2, there is no wafer etching, but the cleaning power is very low.

Claims (13)

In the cleaning composition used for the cleaning process of the wafer cut | disconnected in the solar cell wafer manufacturing process, The detergent composition comprises any one or a mixture of two or more thereof selected from the group consisting of glycol ether compounds, alcohol compounds and surfactants, the surface tension of the detergent composition is characterized in that 20 ~ 60 dyne / cm Battery wafer cleaner composition. The method of claim 1, The glycol ether compound is a wafer cleaning composition for a solar cell, characterized in that the glycol ether compound represented by Formula 1 or Formula 2 or a mixture thereof: [Formula 1] C ₆ H ₅ -CH ₂ O- (CH ₂ CH ₂ O) _m (CH ₂ CHCH ₃ O) _n -H [Formula 2] RO- (CH ₂ CH ₂ O) _m (CH ₂ CHCH ₃ O) _n -H In Formula 1 and Formula 2, m is an integer of 0 to 20, n is an integer of 0 to 20, R is alkyl of 1 to 16 carbon atoms. The method of claim 1, The glycol ether compounds include mono ethylene glycol monobenzyl ether, diethylene glycol mono benzyl ether, triethylene glycol mono benzyl ether, tetraethylene glycol mono benzyl ether, pentaethylene glycol mono benzyl ether, diethylene glycol mono methyl ether, triethylene glycol Mono methyl ether, tetra ethylene glycol mono methyl ether, diethylene glycol mono ethyl ether, triethylene glycol mono ethyl ether, tetra ethylene glycol mono ethyl ether, diethylene glycol mono propyl ether, triethylene glycol mono propyl ether, tetra ethylene glycol mono Propyl ether, diethylene glycol monobutyl ether, triethylene glycol monobutyl ether, tetraethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol Monobutyl ether, dipropylene glycol monobutyl ether, dipropylene glycol monomethyl ether and tripropylene glycol monomethyl any one ether selected from the group consisting of or a solar cell wafer detergent composition, characterized in that these two or more kinds thereof. The method of claim 1, The glycol ether compound is a solar cell wafer cleaning composition, characterized in that contained in an amount of 5 to 80% by weight relative to the total weight of the cleaning composition. The method of claim 1, The alcohol compound is any one selected from the group consisting of ethanol, methanol, protanol, butanol, isopropanol, ethylene glycol, diethylene glycol, propylene glycol, glycerin, sorbitol and polyethylene glycol, or a mixture of two or more thereof. Solar cell wafer cleaning composition. The method of claim 1, The alcohol compound is a solar cell wafer cleaning composition, characterized in that contained in an amount of 1 to 80% by weight relative to the total weight of the cleaning composition. The method of claim 1, The surfactant is a solar cell wafer cleaning composition, characterized in that contained in an amount of 0.1 to 50% by weight relative to the total weight of the cleaning composition. The method of claim 1, The solar cell wafer cleaning composition further comprises an organic acid, an inorganic acid or a mixture thereof. The method of claim 8, The organic acid, inorganic acid or a mixture thereof is any one selected from the group consisting of citric acid, propanoic acid, malonic acid, phthalic acid, carboxylic acid, carbonic acid, hydrofluoric acid and hypophosphoric acid, or a mixture of two or more thereof. A solar cell wafer cleaning composition. 10. The method according to claim 8 or 9, The organic acid, inorganic acid or a mixture thereof is a wafer cleaner composition for a solar cell, characterized in that contained in an amount of 0.1 to 50% by weight relative to the total weight of the detergent composition. The method of claim 1, The wafer cleaner composition is a solar cell wafer cleaner composition, characterized in that it further comprises an organic base, an inorganic base or a mixture thereof. The method of claim 11, The organic base, inorganic base or mixtures thereof include potassium hydroxide, sodium hydroxide, sodium silicate, potassium phosphate, sodium phosphate, potassium carbonate, sodium carbonate, sodium gluconate, ethylenediaminetetraacetic acid, monoethanolamine, diethanolamine, triethanolamine, A morpholine, tetramethylammonium hydroxide and tetraethylammonium hydroxide, any one or a mixture of two or more thereof selected from the group consisting of a solar cell wafer cleaning composition. 13. The method according to claim 11 or 12, The organic base, inorganic base or a mixture thereof is a wafer cleaner composition for a solar cell, characterized in that contained in an amount of 0.1 to 50% by weight relative to the total weight of the cleaning composition.