KR102008881B1 - Composition for cleaning of semiconductor wafer - Google Patents

Abstract

The present invention relates to a composition for cleaning semiconductor wafers, more particularly quaternary ammonium hydroxide; Anionic surfactant represented by the formula (1); And an organic acid, an inorganic acid, or a salt thereof, the present invention relates to a semiconductor wafer cleaning composition which enables manufacturing a semiconductor device having excellent device yield and device characteristics as the cleaning effect is remarkably improved.

Description

Composition for cleaning semiconductor wafers {Composition for cleaning of semiconductor wafer}

The present invention relates to a composition for semiconductor wafer cleaning.

A wafer widely used as a material for manufacturing a semiconductor device today refers to a single crystalline silicon thin film made of polycrystalline silicon as a raw material.

Such wafers include a growth process for growing polycrystalline silicon into a single crystal silicon ingot, a slicing process for cutting the grown single crystal silicon ingot into wafer form, a lapping process to uniformly flatten the thickness of the wafer, and a mechanical process. It is manufactured through an etching process to remove or alleviate damage caused by polishing, a polishing process to mirror the surface of the wafer, and a cleaning process to clean the wafer.

Wafers manufactured in this manner are referred to as polished wafers. An epitaxial wafer, on the other hand, refers to a wafer in which another single crystal film (or “epitaxial layer”) is grown on the surface of a polysid wafer, and has less surface defects than the polysid wafer, and controls the concentration or type of impurities. It is a wafer with possible properties. The epi layer has an advantage of improving the yield and device characteristics of a semiconductor device that is highly integrated due to its high purity and excellent crystal characteristics.

During the slicing process and the polishing process of the wafer manufacturing process, a plurality of silicon particles are adsorbed onto the wafer surface to cause contamination, and thus the wafer surface is cleaned with the cleaning liquid in the cleaning process.

It is known that alkaline aqueous solution is effective as a washing | cleaning liquid normally used for removal of particle contamination. Alkaline aqueous solutions, such as aqueous ammonia, potassium hydroxide, and tetramethylammonium hydroxide, are used to clean the semiconductor wafer surface. In addition, cleaning with a cleaning liquid containing ammonia, hydrogen peroxide, and water (called "SC-1 cleaning liquid" or "APM cleaning liquid") (called "SC-1 cleaning" or "APM cleaning") is also widely used. In recent years, in order to improve the performance of such an alkaline cleaning liquid, it is proposed to add various surfactants.

Among the contaminations, in particular, contamination by microparticles (particles) such as silica particles, alumina particles or organic particles lowers the yield of the device, so it is necessary to reduce as much as possible before entering the next step, thus developing a cleaner having excellent cleaning effect. This is required.

Korean Patent Publication No. 2009-77137 discloses a wafer cleaning liquid.

Korean Patent Publication No. 2009-77137

An object of the present invention is to provide a composition for wafer cleaning having an excellent cleaning effect.

Quaternary ammonium hydroxide; Phosphates represented by Formula 1; And organic acids, inorganic acids or salts thereof.

[Formula 1]

(Wherein R is a linear or branched alkyl or alkenyl group having 1 to 15 carbon atoms and x is an integer of 1 to 30).

2. according to the above 1, wherein the quaternary ammonium hydroxide is tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, cetyltrimethylammonium hydroxide and tetra At least one selected from the group consisting of ethanol ammonium hydroxide, a semiconductor wafer cleaning composition.

3. In the above 1, wherein the quaternary ammonium hydroxide is contained in 0.001 to 50% by weight of the total weight of the cleaning composition, the semiconductor wafer cleaning composition.

4. In the above 1, wherein in Formula 1 R is 6 to 12 carbon atoms, the semiconductor wafer cleaning composition.

5. according to the above 1, wherein the anionic surfactant is contained in 0.001 to 10% by weight of the total weight of the cleaning composition, the semiconductor wafer cleaning composition.

6. In the above 1, the absolute value of the zeta potential is 40mV or more, the semiconductor wafer cleaning composition.

7. In the above 1, the organic acid is formic acid, acetic acid, propionic acid, butyric acid, palmitic acid, stearic acid, oleic acid, oxalic acid, malonic acid, succinic acid, tartaric acid, maleic acid, glycolic acid, glutaric acid, adipic acid , Sulfosuccinic acid, valeric acid, caproic acid, caprylic acid, capric acid, loric acid, myristic acid, lactic acid, malic acid, citric acid, tartaric acid, benzoic acid, salicylic acid, paratoluenesulfonic acid, naphthoic acid, nicotinic acid, toluic acid, ani At least one selected from the group consisting of succinic acid, cuminic acid and phthalic acid; The inorganic acid is at least one selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and carbonic acid, a semiconductor wafer cleaning composition.

8. according to the above 1, wherein the organic acid, inorganic acid or salt thereof is contained in 0.01 to 10% by weight of the total weight of the cleaning composition, the semiconductor wafer cleaning composition.

9. The cleaning method of a semiconductor wafer for cleaning the semiconductor wafer with the cleaning composition of any one of the above 1 to 8.

The cleaning composition of the present invention has a remarkably improved cleaning power against contaminants adhering to the semiconductor wafer surface. As a result, the wafer surface is highly cleaned, allowing the manufacture of a semiconductor device having excellent device yield and device characteristics.

The present invention is quaternary ammonium hydroxide; Anionic surfactant represented by the formula (1); And an organic acid, an inorganic acid, or a salt thereof, the present invention relates to a semiconductor wafer cleaning composition which enables manufacturing a semiconductor device having excellent device yield and device characteristics as the cleaning effect is remarkably improved.

Hereinafter, the present invention will be described in detail.

The composition for cleaning semiconductor wafers of the present invention comprises quaternary ammonium hydroxide.

Quaternary ammonium hydroxides release hydroxide ions, clean the wafer surface and penetrate into the contaminants to promote dissolution of the contaminants.

The quaternary ammonium hydroxide is not particularly limited, and for example, tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, cetyltrimethylammonium hydroxide, tetra Ethanol ammonium hydroxide and the like, and preferably tetramethylammonium hydroxide. These can be used individually or in mixture of 2 or more types.

The quaternary ammonium hydroxide according to the present invention is not particularly limited in its content within the range capable of performing its function, for example, may be included in 0.001 to 50% by weight of the total weight of the cleaning composition. If the content of the quaternary ammonium hydroxide is less than 0.001% by weight, the removal power of the contaminants may not be sufficient, and if the content of the quaternary ammonium hydroxide is more than 50% by weight, damage to the wafer surface may occur. In such aspect, it may be included preferably 0.1 to 20% by weight.

The composition for semiconductor wafer cleaning of the present invention contains an anionic surfactant.

Anionic surfactants according to the invention are represented by the following general formula (1):

[Formula 1]

(Wherein R is a linear or branched alkyl or alkenyl group having 1 to 15 carbon atoms and x is an integer of 1 to 30).

In Formula 1, the oxygen of the hydrophilic portion is hydrogen-bonded with the water molecule, and the hydrophobic portion penetrates between the water molecules to weaken the attraction between the water molecules to reduce the surface tension to serve as a surfactant.

Typically, the hydrophilic portion of the surfactant binds to the contaminant and is removed from the wafer by wrapping it in a hydrophobic portion. Since the anionic surfactant represented by Formula 1 has an alkylphenyl group in the hydrophobic portion, the hydrophobicity is enhanced to contaminants on the wafer. It is possible to increase the removal power of, thereby significantly improving the cleaning power.

When the carbon number of R in the formula (1) is within the above range, it is possible to maximize the effect of improving the cleaning power by strengthening hydrophobicity without inhibiting the binding of the hydrophilic portion with contaminants. In such aspect, it may preferably be 6 to 12 carbon atoms.

In addition, the contaminants on the wafer surface usually have a negative electric charge, because the anionic surfactant according to the present invention exhibits a large amount of negative charges in the composition including a phosphate group, so the repulsive force acts between the contaminants, It further improves cleaning power by allowing contaminants to escape better from the wafer.

The degree of repulsive force can be known by measuring the zeta potential. The cleaning liquid composition of the present invention may have an absolute value of zeta potential of 40 mV or more.

When the colloidal particles in the electrolyte solution are charged, some of the fine particles having charge and counter ions are adsorbed to the interface where the particles come into contact with each other to form a fixed layer, and others diffuse into the solution to form a double layer outside the fixed layer. The potential difference generated between the electric double layers is a zeta potential, and when the absolute value of the zeta potential increases, the repulsive force between particles becomes stronger.

Since the cleaning liquid composition of the present invention has a zeta potential value in the above range, the repulsive force between contaminants acts greatly, and thus the cleaning power is remarkably improved since the contaminants can be easily released from the wafer.

In addition, the anionic surfactant according to the present invention having the above structure has the advantage of generating a solid salt by reaction with other compositions in the cleaning composition and fear of causing odor.

The content of the anionic surfactant according to the present invention is not particularly limited within the range capable of performing its function, for example, may be included in 0.001 to 10% by weight of the total weight of the cleaning composition. If the content of the anionic surfactant is less than 0.001% by weight, the effect of removing pollutants may be insignificant, and if it is more than 10% by weight, the critical micelle concentration may be greater than or not dissolved in water. The effect of improving the material removal power may be insignificant, and due to the generation of a large amount of hydrogen ions, it may be out of the proper pH range. In such aspect, it may be preferably included in 0.01 to 5% by weight.

The semiconductor wafer cleaning composition of the present invention contains an organic acid, an inorganic acid or a salt thereof.

Organic acids, inorganic acids or salts thereof are arranged between contaminants to cause electrical repulsion to improve the dispersibility of the contaminants. This improves the cleaning power. It also acts as a pH adjuster to maintain the proper pH.

The organic acid is not particularly limited, and for example, formic acid, acetic acid, propionic acid, butyric acid, palmitic acid, stearic acid, oleic acid, oxalic acid, malonic acid, succinic acid, tartaric acid, maleic acid, glycolic acid, glutaric acid, adipic acid Aliphatic organic acids such as sulfosuccinic acid, valeric acid, caproic acid, caprylic acid, capric acid, loric acid, myristic acid, lactic acid, malic acid, citric acid and tartaric acid; And aromatic organic acids such as benzoic acid, salicylic acid, paratoluenesulfonic acid, naphthoic acid, nicotinic acid, toluic acid, aniseic acid, cuminic acid and phthalic acid. These can be used individually or in mixture of 2 or more types.

The inorganic acid is not particularly limited, and examples thereof include hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid, and carbonic acid.

A salt is not specifically limited, For example, potassium salt, sodium salt, ammonium salt, calcium salt, magnesium salt, etc. are mentioned.

The content of the organic acid, the inorganic acid or salts thereof is not particularly limited, and may be included, for example, in an amount of 0.01 to 10% by weight of the total weight of the cleaning composition. When the content of the organic acid, inorganic acid or salts thereof is less than 0.01% by weight, the effect of improving dispersibility due to the formation of electrical repulsive force may be insignificant. In addition, in the case of more than 10% by weight, it may exceed the appropriate pH range and the solubility is also lowered, so the effect of improving the cleaning power may be insignificant.

In the cleaning composition of the present invention, after appropriately adopting the above components according to specific needs, water is added to adjust the overall composition so that the remaining amount of the entire composition is occupied by water. Preferably the components are adjusted to have the aforementioned content ranges.

Although the kind of water is not specifically limited, It is preferable that it is deionized distilled water.

The present invention also provides a cleaning method for cleaning a semiconductor wafer with the cleaning composition.

The cleaning method of the present invention is carried out by a method of directly bringing a cleaning composition into contact with a wafer. The method for contacting the cleaning composition to the wafer includes a dip type in which a cleaning composition is filled in a cleaning tank to immerse the wafer, a spin type in which the wafer is rotated at a high speed while flowing the cleaning composition onto the wafer, and a cleaning composition in the wafer. A spray type etc. which spray and wash are mentioned. As an apparatus for performing such a washing | cleaning, there exist a batch type | mold washing | cleaning apparatus which wash | cleans a plurality of wafers accommodated in a cassette simultaneously, the sheet type washing | cleaning apparatus which mounts and wash | cleans one wafer to a holder. The washing method of the present invention can be applied to any of the above methods. The cleaning method of the present invention is preferable because the problem is solved when applied to a single sheet type washing apparatus in which the cleaning time is shortened and the amount of the composition used for cleaning is a problem. In addition, even in a batch type washing apparatus, since high particle removal effect can be acquired, it is preferable.

The washing may be carried out at room temperature, but may be carried out by heating for the purpose of improving the washing effect. Usually, it may be carried out in the range of 20 to 90 ° C, preferably in the range of 40 to 80 ° C.

In the case of batch cleaning, the cleaning time may be generally performed for 30 seconds to 30 minutes, preferably 1 to 15 minutes, and for single sheet cleaning, usually 1 second to 5 minutes, preferably 15 seconds to 1 minute. If the cleaning time is too short, the cleaning effect will not be sufficient. If the cleaning time is too long, throughput will not only decrease, but improvement of the effect suitable for extending the cleaning time cannot be expected.

In addition, at the time of washing | cleaning, you may use together with the washing | cleaning method by a physical force, for example, mechanical cleaning, such as scrap cleaning using a cleaning brush, or ultrasonic cleaning. In particular, the use of ultrasonic irradiation or brush scrap is preferable because the removal of particle contamination is further improved, and the cleaning time can be shortened. In particular, when the wafer is irradiated with an ultrasonic wave of frequency 0.5 MegaHeltz or more, the removal property of particles having a 0.1 μm level is remarkably improved by synergy with the surfactant.

The semiconductor wafer which can be cleaned using the cleaning method of the present invention is not particularly limited and may be used for a semiconductor wafer commonly used in the art, for example, a wafer of a one-element semiconductor such as silicon, germanium, or gallium- Wafers of compound semiconductors, such as phosphorus, gallium arsenide, and indium phosphorus, etc. are mentioned.

Hereinafter, preferred examples are provided to help understanding of the present invention. However, these examples are only for exemplifying the present invention, and do not limit the appended claims, but are within the scope and spirit of the present invention. It will be apparent to those skilled in the art that various changes and modifications can be made to the present invention, and such modifications and changes belong to the appended claims.

Example  And Comparative example

To prepare a semiconductor wafer cleaning composition having the composition and content of Table 1.

division Quaternary Ammonium Hydroxide (A) Anionic Surfactant (B) Organic, inorganic or salts (C) Deionized water
(D) ingredient Parts by weight ingredient Parts by weight ingredient Parts by weight Parts by weight Example 1 A-1 1.5 B-1 0.2 C-1 0.1 98.2 Example 2 A-1 1.5 B-2 0.2 C-1 0.1 98.2 Example 3 A-1 1.5 B-3 0.2 C-1 0.1 98.2 Example 4 A-1 1.5 B-4 0.2 C-1 0.1 98.2 Example 5 A-1 1.5 B-5 0.2 C-1 0.1 98.2 Example 6 A-1 1.5 B-6 0.2 C-1 0.1 98.2 Example 7 A-1 1.5 B-7 0.2 C-1 0.1 98.2 Example 8 A-2 1.5 B-1 0.2 C-2 0.1 98.2 Example 9 A-2 1.5 B-2 0.2 C-3 0.1 98.2 Example 10 A-1 1.5 B-1 5 C-1 0.1 98.2 Example 11 A-1 1.5 B-1 10 C-1 0.1 98.2 Example 12 A-1 1.5 B-1 0.2 C-4 0.1 98.2 Example 13 A-1 1.5 B-2 0.2 C-5 0.1 98.2 Example 14 A-1 1.5 B-1 11 C-1 0.1 98.2 Comparative Example 1 A-1 1.5 B-8 0.2 C-1 0.1 98.2 Comparative Example 2 A-1 1.5 B-9 0.2 C-1 0.1 98.2 Comparative Example 3 A-1 1.5 B-10 0.2 C-1 0.1 98.2 Comparative Example 4 A-1 1.5 B-11 0.2 C-1 0.1 98.2 A-1: Tetramethylammonium Hydroxide
A-2: tetrabutylammonium hydroxide
B-1: C _n H _{2n +} 1-(Phenyl) -O- (EO) _x- (Phosphate) (2H) (n = 6, x = 10, EO = oxyethylene group)
B-2: C _n H _{2n +} 1-(Phenyl) -O- (EO) _x- (Phosphate) (2H) (n = 9, x = 10, EO = oxyethylene group)
B-3: C _n H _{2n +} 1-(Phenyl) -O- (EO) _x- (Phosphate) (2H) (n = 10, x = 10, EO = oxyethylene group)
B-4: C _n H _{2n +} 1-(Phenyl) -O- (EO) _x- (Phosphate) (2H) (n = 12, x = 10, EO = oxyethylene group)
B-5: C _n H _{2n +} 1-(Phenyl) -O- (EO) _x- (Phosphate) (2H) (n = 1, x = 10, EO = oxyethylene group)
B-6: C _n H _{2n +} 1-(Phenyl) -O- (EO) _x- (Phosphate) (2H) (n = 3, x = 10, EO = oxyethylene group)
B-7: C _n H _{2n +} 1-(Phenyl) -O- (EO) _x- (Phosphate) (2H) (n = 15, x = 10, EO = oxyethylene group)
B-8: EO / PO block copolymer
(50% ethylene oxide, weight average molecular weight 2,500, PO = oxypropylene group)
B-9: C _n H _{2n +1} -O- (EO) _x (PO) _y -H (n = 9, x = 10, y = 10)
B-10: C _n H _{2n +1} -O- (EO) _x -H (n = 9, x = 10)
B-11: C _n H _{2n +1} -O- (EO) _x- (Phosphate) (2H) (n = 9, x = 10)
C-1: citric acid
C-2: glutaric acid
C-3: oxalic acid
C-4: phosphoric acid,
C-5: ammonium citrate

Experimental Example

(1) zeta potential measurement

10 mL of the cleaning solution compositions of Examples and Comparative Examples were placed in Quarz Cells, and zeta potentials were measured using a Zeta Potentiometer (ELS-Z, Otsuka Electronics Co., Ltd.). The above procedure was repeated 10 times, and the average value thereof is shown in Table 2 below.

(2) evaluation of cleaning power

Initial weights of 6-inch P-type silicon wafers were measured. After the CMP slurry (Colloidal Silica Particles, diameter 0.03 ~ 0.1㎛) coated on the wafer for 10 seconds at 1,500rpm using a coater (manufacturer: DNS model name: SK-200W) and baked for 10 minutes at 80 ℃ The weight was measured.

Thereafter, the wafers were immersed in the cleaning compositions of Examples and Comparative Examples for 5 minutes, and then washed, and then washed with deionized water for 5 seconds and dried at room temperature. After measuring the weight of the dried wafer, the removal rate (cleaning force) of the CMP slurry of the cleaning composition was determined according to Equation 1 below.

[Equation 1]

% Removal = (Weight of slurry after slurry coating-Weight of cleaned wafer) / (Weight of wafer after slurry coating-Weight of wafer before slurry coating)

The results are shown in Table 2 below.

division Zeta potential (mV) Removal rate
(Washing power,%) division Zeta potential (mV) Removal rate
(Washing power,%) Example 1 -48.44 99 Example 10 -46.98 97 Example 2 -49.16 100 Example 11 -46.28 96 Example 3 -47.89 98 Example 12 -45.24 96 Example 4 -48.14 98 Example 13 -44.28 96 Example 5 -43.89 96 Example 14 -38.14 93 Example 6 -46.09 97 Comparative Example 1 -30.96 90 Example 7 -43.69 96 Comparative Example 2 -28.37 89 Example 8 -46.03 96 Comparative Example 3 -27.41 85 Example 9 -46.39 97 Comparative Example 4 -34.79 90

Referring to Table 2, the cleaning compositions of Examples 1 to 13, the absolute value of the zeta potential is all 40mV or more, the repulsion between the contaminants is very high, it can be seen that exhibits a very good cleaning power of 96% or more.

Example 14, which includes an anionic surfactant in an excess amount beyond the preferred range, had a slightly lower effect than other examples, but still showed excellent performance.

However, in the cleaning compositions of Comparative Examples 1 to 4, the absolute value of the zeta potential dropped to less than 35, so that the repulsive force between contaminants was low, and the cleaning power was lowered to confirm that many CMP slurries remained.

Claims (9)

Quaternary ammonium hydroxides;
Anionic surfactant represented by the formula (1); And
Organic acids, inorganic acids or salts thereof;
A composition for cleaning a semiconductor wafer, wherein the absolute value of the zeta potential is 40 mV or more:
[Formula 1]

(Wherein R is a linear or branched alkyl or alkenyl group having 1 to 15 carbon atoms,
x is an integer from 1 to 30.
The method of claim 1, wherein the quaternary ammonium hydroxide is tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide, cetyltrimethylammonium hydroxide and tetraethanolammonium At least one selected from the group consisting of hydroxide, a semiconductor wafer cleaning composition.
The semiconductor wafer cleaning composition according to claim 1, wherein the quaternary ammonium hydroxide is contained in an amount of 0.001 to 50% by weight based on the total weight of the cleaning composition.
The composition according to claim 1, wherein in Formula 1, R has 6 to 12 carbon atoms.
The semiconductor wafer cleaning composition of claim 1, wherein the anionic surfactant is present in an amount of 0.001 to 10% by weight based on the total weight of the cleaning composition.
delete The method of claim 1, wherein the organic acid is formic acid, acetic acid, propionic acid, butyric acid, palmitic acid, stearic acid, oleic acid, oxalic acid, malonic acid, succinic acid, tartaric acid, maleic acid, glycolic acid, glutaric acid, adipic acid, sulfo Succinic acid, valeric acid, caproic acid, caprylic acid, capric acid, loric acid, myristic acid, lactic acid, malic acid, citric acid, tartaric acid, benzoic acid, salicylic acid, paratoluenesulfonic acid, naphthoic acid, nicotinic acid, toluic acid, aniseic acid, At least one selected from the group consisting of cuminic acid and phthalic acid; The inorganic acid is at least one selected from the group consisting of hydrochloric acid, sulfuric acid, nitric acid, phosphoric acid and carbonic acid, a semiconductor wafer cleaning composition.
The semiconductor wafer cleaning composition of claim 1, wherein the organic acid, the inorganic acid, or a salt thereof is included in an amount of 0.01 to 10 wt% based on the total weight of the cleaning composition.
The cleaning method of a semiconductor wafer which wash | cleans a semiconductor wafer with the cleaning composition of Claim 1.