JP2014172965A - Detergent compositions - Google Patents

Abstract

ただし、式中Ｒ^１は炭素数１０〜１４のアルキル基もしくはアルケニル基であり、ＡＯは炭素数２〜４のオキシアルキレン基であり、ｎは平均付加モル数であり、１〜４０の数である。
【選択図】なしDisclosed is a cleaning composition that can remove impurities adhering during silicon wafer production even under simpler cleaning conditions.
A cleaning composition containing (a) an alkali agent, (b) a polyhydric alcohol, (c) a nonionic surfactant represented by the following general formula (1) and water is used.
[Chemical 1]

In the formula, R ¹ is an alkyl group or alkenyl group having 10 to 14 carbon atoms, AO is an oxyalkylene group having 2 to 4 carbon atoms, n is an average added mole number, and a number of 1 to 40 is there.
[Selection figure] None

Description

  The present invention relates to a cleaning composition mainly used for cleaning silicon wafers.

  Silicon wafers used for semiconductor applications such as solar cells are required to reduce impurities remaining on the surface as much as possible.

  For example, in a process of manufacturing a silicon wafer by slicing a silicon ingot, a slurry containing a cutting fluid (coolant), silicon powder, abrasive grains, or the like adheres to the cut material, and thus it is necessary to efficiently remove this. . In recent years, wire saw systems using fixed abrasive grains have been implemented, and there is a demand for removal of slurry adhered to fine cracks (saw marks) generated during slicing. It is also necessary that the rinse after washing is easy.

  Furthermore, in silicon wafers for solar cells, a pyramid structure called a texture structure is formed by etching on the surface of the silicon wafer in order to improve energy conversion efficiency. In particular, in single crystal silicon wafers, etching including sodium hydroxide is performed. Liquid is used. Therefore, it is necessary to sufficiently remove these etching solutions in the texture forming step.

  As a cleaning agent used for cleaning at the time of manufacturing a silicon wafer as described above, a cleaning agent containing an alkali agent, a surfactant, a chelating agent, or the like is disclosed (Patent Document 1, etc.).

  However, when the conventional cleaning agent as described above is used for cleaning at the time of manufacturing a silicon wafer, there is a problem that impurities cannot be sufficiently removed unless an operation such as ultrasonic cleaning is performed.

JP 2006-265469 A

  The present invention has been made in view of the above, and provides a cleaning composition having excellent detergency capable of removing impurities adhering during the production of a silicon wafer even under simpler washing conditions and having high rinsing properties. For the purpose.

In order to solve the above problems, the cleaning composition of the present invention has (a) an alkaline agent, (b) a polyhydric alcohol, (c) a nonionic surfactant represented by the following general formula (1), and water. It shall contain.

In the formula, R ¹ is an alkyl group or alkenyl group having 10 to 14 carbon atoms, AO is an oxyalkylene group having 2 to 4 carbon atoms, n is an average added mole number, and a number of 1 to 40 is there.

  In the cleaning composition of the present invention, the (b) polyhydric alcohol can contain 50 to 100% by weight of an oxyethylene group. (B) The polyhydric alcohol preferably has 4 to 12 hydroxyl groups in the molecule.

  The detergent composition of the present invention is a nonionic surfactant represented by (b) a polyhydric alcohol in an amount of 5 to 1000 parts by mass and (c) the general formula (1) with respect to 100 parts by mass of the alkali agent (a). It is preferable to contain 5-1000 mass parts.

  Although content of each component in a cleaning composition is not limited, For example, (a) 0.05-30 mass% of alkali agents, (b) 0.05-30 mass% of polyhydric alcohol, (c) The nonionic surfactant represented by the general formula (1) may be contained in an amount of 0.05 to 30% by mass.

  The detergent composition of the present invention may further contain (d) a solubilizer. Further, (e) a metal ion sealing agent can be further contained.

  The cleaning composition of the present invention can be suitably used for cleaning silicon wafers.

  The cleaning method of the present invention uses any of the above-described cleaning compositions of the present invention.

  The cleaning composition of the present invention has excellent cleaning properties and high rinsing properties capable of removing impurities adhering during silicon wafer production only by simple cleaning conditions such as immersing without operation such as ultrasonic cleaning. Become. It has high detergency that can be removed only by simple washing conditions such as soaking.

  The cleaning composition of the present invention comprises (a) an alkaline agent, (b) a polyhydric alcohol, (c) a nonionic surfactant represented by the general formula (1) and water as described above, It can be suitably used for cleaning a silicon wafer, and can also be used for cleaning after texture formation by etching. In the cleaning after the silicon wafer slicing step, the cleaning property is extremely excellent and the rinsing property is high, and when used in the cleaning after the texture formation, the wafer surface shape retention effect is high.

  (A) Alkaline agent used in the present invention is not particularly limited, and examples include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, sodium silicate, potassium silicate, phosphoric acid. Inorganic alkaline compounds such as sodium, potassium phosphate, dibasic sodium phosphate, dibasic potassium phosphate, tribasic sodium phosphate, tribasic potassium phosphate and ammonia, tetramethylammonium hydroxide, monoethanolamine, diethanolamine, Ethanolamine, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, triethylamine, methylethanolamine, dimethylethanolamine, methyldiethanolamine, ethylethanolamine, diethylethanolamine Down, ethyl diethanolamine, organic alkali compounds such as cyclohexylamine and triisopalmitate Nord amines. Of these, sodium hydroxide and potassium hydroxide are preferred because of their excellent detergency.

  The (b) polyhydric alcohol used in the present invention is a compound having two or more hydroxyl groups. In the present invention, the use of polyhydric alcohol can further improve the cleaning property and gap cleaning property of the cleaning composition, and when used for cleaning after texture formation, the wafer surface shape retention effect is also excellent. It will be.

  Examples of polyhydric alcohols include compounds having two hydroxyl groups such as ethylene glycol, propylene glycol, 1,4-butanediol, 1,5-pentanediol and 2-methyl-2,4-pentanediol, glycerin and the like. Compounds having 3 hydroxyl groups, compounds having 4 hydroxyl groups such as pentaerythritol, compounds having 5 hydroxyl groups such as glucose and fructose, compounds having 6 hydroxyl groups such as sorbitol, dipentaerythritol and galactitol, tripentaerythritol And compounds having 8 hydroxyl groups such as sucrose. Polyglycerin can also be used. Of these, a compound having 4 to 12 hydroxyl groups is preferable, and a compound having 4 to 8 hydroxyl groups is more preferable because of excellent cleaning properties, gap cleaning properties, and wafer surface shape retention effects.

  Moreover, the compound which added C2-C4 alkylene oxide to the above polyhydric alcohol can also be used. The alkylene oxide preferably contains 50% by weight or more of ethylene oxide, more preferably 80% by weight or more, further preferably 90% by weight or more, and most preferably polyethylene glycol having a content of 100% by weight. Moreover, it is preferable that the addition mole number (average addition mole number, hereafter the same) of alkylene oxide is 1-30 mol.

The (c) nonionic surfactant used in the present invention is not particularly limited, and a wide variety of compounds used in various detergent compositions can be used, but those obtained by adding an alkylene oxide to an alcohol are preferred. What is represented by the following general formula (1) is more preferable.

In the formula (1), R ¹ represents an alkyl group or alkenyl group having 10 to 14 carbon atoms, AO represents an oxyalkylene group having 2 to 4 carbon atoms, n is an average added mole number, and 1 to 40 Indicates a number.

As a specific example, when R ¹ is an alkyl group, a decyl group, an isodecyl group, an undecyl group, a dodecyl group, tridecyl group, tetradecyl group and the like, when R ¹ is an alkenyl group, decenyl group, Isodeseniru group, undecenyl Group, dodecenyl group, tridecenyl group, tetradecenyl group and the like. Examples of AO include ethylene oxide, propylene oxide, and butylene oxide. Among them, it is preferable to contain ethylene oxide, and the average added mole number of ethylene oxide is preferably 2 to 30 mol, more preferably 3 to 20 mol, and further preferably 5 to 15 mol. n is more preferably in the range of 2-20. By setting it within the above range, the rinsing property can be further improved.

  If necessary, the detergent composition of the present invention may further contain (d) a solubilizer. When the cleaning composition of the present invention is an aqueous solution containing the above (a) to (c) at a high concentration, the dissolution of these components may be insufficient and precipitation may occur. By doing so, the solubility of each of these components can be improved, the transparency of the aqueous solution can be ensured, and the storage stability can be further improved.

  Although the (d) solubilizer used by this invention is not specifically limited, As an example, the salt of alkyl polyglucoside, an organic acid, and an organic acid is mentioned. Examples of alkyl polyglucosides include propyl polyglucoside, butyl polyglucoside, hexyl polyglucoside, octyl polyglucoside, nonyl glucoside, decyl glucoside, decyl maltoside, dodecyl maltoside, tridecyl maltoside and the like. Examples of organic acids include cumene sulfonic acid, toluene sulfonic acid, xylene sulfonic acid, naphthalene sulfonic acid, dimethylbenzene sulfonic acid, octanoic acid, 2-ethylhexanoic acid and the like. As the organic acid, metal ion salts such as sodium salt, potassium salt and lithium salt of the above organic acid are also used, and ammonia, monoethanolamine, diethanolamine, triethanolamine, methylamine, dimethylamine, trimethylamine, ethylamine, Also usable are salts of onium ions such as diethylamine, triethylamine, methylethanolamine, dimethylethanolamine, methyldiethanolamine, ethylethanolamine, diethylethanolamine, and ethyldiethanolamine.

  As the solubilizer, alkylpolyglucoside is preferable among these because the stabilizing effect of the detergent composition is high.

  In order to further improve the cleaning effect, the cleaning composition of the present invention may further contain (e) a metal ion sealing agent as necessary. The type of the metal ion sealant is not particularly limited, and compounds used in various detergent compositions can be widely used. Preferred examples include ethane-1,1-diphosphonic acid and ethane- 1,1,2-triphosphonic acid, 1-hydroxyethane-1,1-diphosphonic acid (HEDP), ethanehydroxy-1,1,2-triphosphonic acid, ethane-1,2-dicarboxy-1,2-diphosphone Acid, methanehydroxyphosphonic acid, nitrilotrimethylenephosphonic acid (NTMP), 3-carboxy-3-phosphonohexanedioic acid (PBTC), ethylenediaminetetrakismethylenephosphonic acid, L-glutamic acid diacetic acid, methylglycine diacetic acid, gluconic acid, Glycolic acid, ethylenediaminetetraacetic acid, nitrilotriacetic acid, iminodiacetic acid, hydroxyethyl ether Diamine triacetic acid, diethylenetriaminepentaacetic acid, glycol ether diaminetetraacetic acid, hydroxyethylene diamine tetramine hexaacetic acid, hydroxyethyliminodiacetic acid, triethylenetetraminehexaacetic acid, citric acid, malic acid, and salts thereof.

  In the cleaning composition of the present invention, in addition to the above-mentioned components, known additives such as antifoaming agents, preservatives, rust preventives, antioxidants, pH adjusting agents, etc. Can be blended as appropriate.

  The blending ratio of the components (a) to (c) is preferably 5 to 1000 parts by weight, more preferably 10 to 800 parts by weight, based on (a) 100 parts by weight of the alkali agent, and (b) polyhydric alcohol. 20-500 weight part is still more preferable. By making it within the above range, the cleaning property is more excellent, and when used for cleaning after texture formation, the wafer surface shape retention effect is more excellent. Moreover, 5-1000 mass parts are preferable with respect to 100 mass parts of (a) alkali agents, (c) nonionic surfactant is more preferable, 10-800 mass parts is more preferable, and 20-500 mass parts is still more preferable. By setting it within the above range, the balance between the cleaning property and the rinsing property is further improved.

  Moreover, the blending ratio when (d) the solubilizer is used is preferably 5 to 1000 parts by mass, more preferably 10 to 800 parts by mass, and more preferably 20 to 500 parts by mass with respect to 100 parts by mass of the (a) alkali agent. Further preferred. Furthermore, (c) 5-1000 mass parts is preferable with respect to 100 mass parts of nonionic surfactant, 10-800 mass parts is more preferable, and 50-500 mass parts is still more preferable. By setting it within the above range, it is possible to prepare an aqueous solution containing the cleaning composition at a high concentration, and it is excellent in storage stability and is more easily diluted with water at the time of use. Moreover, the rinsing property is more excellent.

  The cleaning composition of the present invention comprises the components (a) to (c) described above, the component (d) and / or the component (e) used as necessary, and the remaining water. Accordingly, it can be used in a wide range of concentrations. Therefore, although the compounding amount (concentration) of each of the components (a) to (e) in the cleaning composition cannot be uniformly shown, an example is shown below.

  The blending amount of the alkali agent (a) is preferably 0.05 to 30% by mass, more preferably 0.1 to 25% by mass, and further preferably 0.2 to 20% by mass. By setting it within the above range, the cleaning property becomes more excellent.

  The blending amount of the (b) polyhydric alcohol is preferably 0.05 to 30% by mass, more preferably 0.1 to 25% by weight, and still more preferably 0.1 to 20% by weight. By setting it within the above range, the cleaning properties are more excellent. Further, in the cleaning after the texture formation, the wafer surface shape retention effect is more excellent.

  0.05-30 mass% is preferable, as for the compounding quantity of the said (c) nonionic surfactant, 0.1-25 mass% is more preferable, and 0.1-20 mass% is still more preferable. By setting it within the above range, the balance between the cleaning property and the rinsing property becomes more excellent.

  0.05-40 mass% is preferable, as for the compounding quantity in the case of using the said (d) solubilizer, 0.1-30 mass% is more preferable, 0.2-20 mass% is still more preferable. By setting it within the above range, dilution with water becomes easier and rinsing properties are more excellent.

  0.01-20 mass% is preferable, as for the compounding quantity in the case of using the said (e) metal ion sealing agent, 0.05-15 mass% is more preferable, 0.1-10 mass% is further more preferable. By setting it within the above range, the amount of metal remaining on the surface of the silicon wafer can be further reduced, and the rinsing property is further improved.

  As described above, the cleaning composition of the present invention can be suitably used for general cleaning of silicon wafers, that is, for both rough cleaning and finishing cleaning after the silicon wafer slicing step, and cleaning after texture formation by etching. However, it can also be used for various other objects to be cleaned as necessary.

  When a silicon wafer is cleaned using the cleaning composition of the present invention, the above-mentioned examples shown as examples of the blending amount (concentration) can be used as they are, and this is diluted with water as a stock solution. You can also When diluting the above compounded amount with water, it is preferable to dilute to 100 times or less (however, based on volume, the same applies hereinafter). When the dilution ratio exceeds 100 times, the detergency deteriorates.

  The cleaning method is not particularly limited, and a conventionally known cleaning method can be appropriately used. Examples include immersion cleaning, ultrasonic cleaning, brush cleaning, scrub cleaning, jet cleaning, spray cleaning, hand cleaning, and combinations thereof. However, since the cleaning composition of the present invention has a high cleaning effect, a sufficient cleaning effect can be obtained even by simple means such as immersion.

  After washing, depending on the purpose of use, it can be dried as it is, or it can be rinsed with water and dried.

  Next, although this invention is demonstrated based on an Example and a comparative example, this invention is not limited to these Examples. In the following description, “part” or “%” is based on mass unless otherwise specified.

  Each cleaning composition was prepared by mixing the raw materials described in Tables 1 to 3 in the blending amounts shown in these tables, and the following evaluation was performed. Details of the raw materials are as follows. The results are shown in Tables 1-3.

(A) Alkaline agent (a-1) Sodium hydroxide (a-2) Potassium hydroxide (b) Polyhydric alcohol (b-1) Polyethylene glycol (Mole number of ethylene oxide added: 5)
(B-2) Polyethylene glycol (Mole number of ethylene oxide added: 10)
(B-3) Polyethylene glycol (Mole number of ethylene oxide added: 15)
(B-4) Sorbitol (b-5) Sucrose (c) Nonionic surfactant (c-1) Compound obtained by adding 7 mol of ethylene oxide to isodecyl alcohol (c-2) Ethylene oxide 12 to isodecyl alcohol Compound in which 2 moles of propylene oxide are randomly added (c-3) Compound in which 8 moles of ethylene oxide and 2 moles of propylene oxide are randomly added to dodecyl alcohol (c-4) Compound in which 8 moles of ethylene oxide are added to tridecyl alcohol (D) Solubilizer (d-1) Butyl polyglucoside (d-2) Sodium paratoluenesulfonate (e) Metal ion sequestering agent (e-1) Sodium gluconate (e-2) Sodium ethylenediaminetetraacetate

(1) Evaluation in silicon wafer manufacturing process (cleanability)
A mixture of wire saw oil (manufactured by Palace Chemical Co., Ltd., PS-DWS-8) and silicon powder (average particle diameter of 1 μm) at a mass ratio of 90:10 was used as a model of the object to be cleaned. One single-crystal silicon wafer (size: 156 mm × 156 mm) sliced by the fixed abrasive method was completely immersed in the model liquid of the object to be cleaned, and the pulled up was used as a test piece.

  A 10-fold diluted product of each cleaning composition in Tables 1 to 3 was prepared, adjusted to 60 ° C., immersed in the test piece for 10 minutes, and further immersed in ion-exchanged water at 40 ° C. for 10 minutes. Then, after immersing a test piece in 25 degreeC ion-exchange water for 10 minutes, it dried for 20 minutes with an 80 degreeC dryer.

The removal area ratio (%) of the object to be cleaned on the wafer surface was determined, and the average value was defined as the cleaning property (%). In the determination, a grid-like frame (10 × 10 squares) having the same size as the wafer was created, and this was applied to the cleaned wafer and the squares were counted to obtain the area. Moreover, this detergency was evaluated according to the following criteria. The results are shown in Tables 1-3.
○: Good (cleanability of 98% or more)
Δ: Partially remaining cleaning (cleanability 90% or more and less than 98%)
×: Defect (less than 90% cleanability)

(Gap cleaning)
A mixture of wire saw oil (manufactured by Palace Chemical Co., Ltd., PS-DWS-8) and silicon powder (average particle diameter of 1 μm) at a mass ratio of 90:10 was used as a model of the object to be cleaned. This was set between two single crystal silicon wafers (size: 156 mm × 156 mm) sliced by the fixed abrasive method. At this time, the interval between the wafers was fixed at 150 μm to obtain a test piece.

  Prepare a 20-fold diluted product of each of the cleaning agents in Tables 1-3, adjust the temperature to 50 ° C., immerse the test piece for 10 minutes, and further immerse the test piece in 25 ° C. ion-exchanged water for 10 minutes. .

After the treatment, two wafers were opened, the removal area ratio (%) of the object to be cleaned on the wafer surface was determined, and the average value was defined as the cleaning property (%). In the determination, a grid-like frame (10 × 10 squares) having the same size as the wafer was created and applied to the wafer after cleaning to obtain a removal area. Moreover, the cleaning property was evaluated according to the following criteria based on the removal area ratio. The results are shown in Tables 1-3.
○: Good (detergency 80% or more)
Δ: Partially remaining cleaning (detergency: 50% to less than 80%)
X: Defect (cleanability less than 50%)

(2) Evaluation in the texture forming step A single crystal silicon wafer (size: 156 mm × 156 mm) is immersed for 20 minutes in an etching solution adjusted to 80 ° C. by adding 5 mass% of isopropyl alcohol to a 5 mass% sodium hydroxide aqueous solution. Furthermore, a texture was formed on the surface of the silicon wafer by washing with ion-exchanged water. This was completely immersed in aqua regia (nitric acid: hydrochloric acid = 1: 3), and then rinsed with ion-exchanged water to remove metal ions and organic residues, thereby producing a silicon wafer test piece.

  A 10-fold diluted product of each cleaning agent in Tables 1 to 3 was prepared, adjusted to 60 ° C., immersed in the test piece for 10 minutes, and further immersed in ion-exchanged water at 40 ° C. for 10 minutes. Thereafter, the test piece was immersed in 25 ° C. ion-exchanged water for 10 minutes, and then dried for 20 minutes in an 80 ° C. dryer to prepare a test piece. Using the obtained test piece, the rinsability and the wafer surface shape were evaluated as follows.

(Rinse)
Organic components (cleaner residue) on the wafer surface are analyzed by wafer thermal desorption-gas chromatography-mass spectrometry (Shimadzu Corporation, GCMS-QP2010 Plus), and the organic components remaining on one side of the wafer (per 243 cm ² ). Was calculated in terms of hexadecane and evaluated according to the following criteria. The results are shown in Tables 1-3.
○: Good (less than 1.00 μg)
Δ: Some detergent remaining (1.00 μg or more and less than 10.0 μg)
X: Defect (10.0 μg or more)

(Wafer surface shape)
The texture shape of the wafer surface was observed using a scanning electron microscope (JEOL Ltd., JSM-6380LV). The evaluation was performed according to the following criteria in comparison with the test piece before cleaning at a total of nine locations including the four corners of the wafer, the center point of the wafer, and the midpoint of each side of the wafer. The results are shown in Tables 1-3.
○: Texture structure is maintained ×: Texture size change or disappearance

(Surface reflectance)
The reflectance of the test piece at a wavelength of 600 nm was measured using an ultraviolet / visible spectrophotometer (Hitachi High-Technologies Corporation, U-3900H). The results are shown in Tables 1-3. The reflectance of the test piece is 12%, and the reflectance increases as the texture shape of the wafer surface changes.

  From the results shown in Tables 1 to 3, according to the cleaning composition of the present invention, as a synergistic effect by the combined use of the components (a) to (c), the cleaning effect in cleaning silicon wafers is remarkably excellent, and rinsing is performed. It is also found that the wafer surface shape retention effect is high when used for cleaning after texture formation.

Claims (8)

A cleaning composition comprising (a) an alkali agent, (b) a polyhydric alcohol, (c) a nonionic surfactant represented by the following general formula (1), and water.

In the formula, R ¹ is an alkyl group or alkenyl group having 10 to 14 carbon atoms, AO is an oxyalkylene group having 2 to 4 carbon atoms, n is an average added mole number, and a number of 1 to 40 is there.   The cleaning composition according to claim 1, wherein the (b) polyhydric alcohol contains 50 to 100% by weight of an oxyethylene group.   The cleaning composition according to claim 1, wherein the (b) polyhydric alcohol has 4 to 12 hydroxyl groups in the molecule.   5 to 1000 parts by mass of the (b) polyhydric alcohol and 5 to 1000 parts by mass of the nonionic surfactant represented by the general formula (1) with respect to 100 parts by mass of the (a) alkali agent. The cleaning composition according to any one of claims 1 to 3, wherein:   (A) 0.05-30 mass% of the alkali agent, (b) 0.05-30 mass% of the polyhydric alcohol, and (c) the nonionic surfactant represented by the general formula (1) It contains 0.05-30 mass%, The cleaning composition of any one of Claims 1-3 characterized by the above-mentioned.   (D) The detergent composition according to any one of claims 1 to 5, further comprising a solubilizer.   The cleaning composition according to any one of claims 1 to 6, wherein the cleaning composition is used for cleaning a silicon wafer.   A cleaning method for a silicon wafer, wherein the cleaning composition according to claim 1 is used.