JP2011146460A - Method for cleaning surface of silicon wafer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for cleaning a surface of a silicon wafer by which fine particles of an organic material and metal deposited on the surface of the wafer can be removed with high precision and with small consumption of chemicals. <P>SOLUTION: An ozone gas is brought into contact with the wafer surface to form an oxide film on the wafer surface (step S1), a hydrogen fluoride gas is brought into contact with the wafer surface to remove the oxide film formed on the wafer surface (step S2), and the wafer surface is cleaned using a dicarboxylic chemical solution of oxalic acid or citric acid to prevent redeposition of fine particles and to remove metal particles (step S3). Further, the wafer surface is cleaned using ozone water to remove fine particles, and another oxide film is formed (step S4). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for cleaning a surface of a silicon wafer, and more particularly, to a method for cleaning a surface suitable for removing fine particles such as organic substances and metals adhering to the surface of a silicon wafer.

  In the manufacturing process of a silicon wafer (hereinafter also referred to as “wafer”), the wafer is cleaned before and after various manufacturing processes. For example, before the epitaxial growth treatment, in order to remove silica abrasive grains remaining in the polishing process and fine particles such as organic substances adhering from the apparatus, single wafer cleaning is repeatedly performed using ozone water and hydrofluoric acid water. Is going. In this surface cleaning method, ozone water and hydrofluoric acid water are alternately supplied to the surface of the wafer while rotating the wafer, and fine particles such as organic substances and metals adhering to the wafer surface are cleaned and removed together with a chemical solution.

  Further, an oxidizing gas was brought into contact with the wafer to form an oxide film on the wafer surface, and then the wafer was brought into contact with a mixed vapor of organic solvent vapor and water vapor to form a liquid film of the mixed vapor on the wafer. In this state, there has been proposed a method of cleaning a wafer by bringing an etching gas into contact with the wafer and etching and removing the oxide film (see, for example, Patent Document 1).

JP 2005-19787 A

  However, in the conventional surface purification method using ozone water and hydrofluoric acid water, due to the surface tension of the liquid, the chemical cannot enter the minute recesses on the wafer surface or the back side of the fine particles. The removal of adhering fine particles, particularly small-sized particles, was insufficient. In addition, a considerable amount of chemical solution is required to clean the wafer surface, resulting in a high cost.

  Further, in the method described in Patent Document 1 that uses an oxidizing gas to form an oxide film, before the step of removing the oxide film, an organic solvent vapor and water vapor are brought into contact with the wafer to form a liquid film on the wafer. Form. However, since the molecules of the etching gas do not penetrate evenly into the liquid film, the etching does not proceed uniformly in the surface, and there is a problem that the fine particles are not separated (lifted off) from the wafer efficiently.

  Accordingly, the object of the present invention made by paying attention to these points is silicon that can remove fine particles such as organic matter and metal adhering to the wafer surface with less residual fine particles with a small amount of chemical solution used. An object of the present invention is to provide a wafer surface cleaning method.

A method of cleaning the surface of a silicon wafer according to the present invention that achieves the above object,
A first surface layer reforming process in which an oxidizing gas is brought into contact with the surface of the silicon wafer, and the surface layer including the wafer surface is used as a first oxide film;
A surface layer removing step of contacting the wafer surface with an etching gas to remove the first oxide film;
A second surface layer modification treatment step of contacting a chemical solution having an oxidizing action with the wafer surface from which the first oxide film has been removed to remove fine particles remaining on the wafer surface and to form a second oxide film; It is characterized by having.

  In the silicon wafer surface purification method described above, the gas having an oxidizing action is preferably ozone gas.

  The gas having an etching action is preferably a hydrogen fluoride-containing gas. Further, the hydrogen fluoride-containing gas contains methanol, ethanol, or isopropyl alcohol vapor, or citric acid gas or oxalic acid gas, or methanol, ethanol, or isopropyl alcohol vapor. It is preferable to contain either of these, citric acid gas, or oxalic acid gas.

  Moreover, it is preferable that the chemical | medical solution with an oxidizing action is ozone water or hydrogen peroxide water.

  Furthermore, as an embodiment of the present invention, it is preferable to further include a pure water rinsing process for cleaning the silicon wafer with pure water and a drying process for drying the cleaned silicon wafer following the second surface layer reforming process. .

  In addition, it is preferable to further include an organic acid rinsing step for cleaning the wafer surface using an organic acid chemical solution to remove metal particles between the surface layer removing step and the second surface layer modifying treatment step. Chemical solutions of oxalic acid, citric acid, succinic acid, ethylenediaminetetraacetic acid, tartaric acid, salicylic acid, formic acid, maleic acid, propionic acid, acetic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, benzoic acid, acrylic acid Adipic acid, malonic acid, malic acid, glycolic acid, phthalic acid, terephthalic acid or fumaric acid is preferred.

  According to the present invention, an oxidizing gas is brought into contact with the wafer surface, the surface layer including the wafer surface is used as the first oxide film, and then an etching gas is brought into contact with the wafer surface to Since the oxide film is removed, and the fine particles remaining on the wafer surface are removed and the second oxide film is formed using an oxidizing chemical solution, the wafer surface can be used with a small amount of chemicals used. Fine particles such as organic substances and metals adhering to the surface can be removed so that there are fewer residual fine particles.

It is a block diagram which shows schematic structure of the washing | cleaning apparatus used when enforcing the method which concerns on one Embodiment of this invention. It is a schematic block diagram of the washing | cleaning apparatus main body of FIG. It is a flowchart which shows the procedure at the time of implementing the method which concerns on one Embodiment of this invention. It is a figure explaining the surface purification principle of a silicon wafer.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

  First, with reference to FIG. 1 and FIG. 2, the structure of the washing | cleaning apparatus used when applying the washing | cleaning method of this invention is demonstrated. FIG. 1 is a block diagram showing a schematic configuration of a cleaning apparatus used when performing a method according to an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of the cleaning apparatus main body of FIG.

  As shown in FIG. 1, the wafer cleaning apparatus 10 includes a sealable single wafer cleaning apparatus main body 11 loaded with a polished wafer, a first gas supply pipe system 12 for supplying ozone gas, and a cleaning apparatus main body. To supply nitrogen gas or a second gas supply pipe system 13 for supplying nitrogen gas or a mixed gas of nitrogen gas and hydrogen fluoride gas and / or organic solvent vapor, and ozone water, an organic acid chemical solution, or pure water Liquid supply pipe system 14.

  The first gas supply pipe system 12 includes an ozone gas supply unit 16, a pipe 17 that connects the ozone gas supply unit 16 and the cleaning apparatus main body 11, and a flow rate regulator 18 that is disposed in the pipe 17.

  The second gas supply pipe system 13 includes a nitrogen gas supply unit 20, a hydrogen fluoride gas supply unit 21, and an organic solvent vapor supply unit 22. The nitrogen gas supply unit 20 is connected to the cleaning device main body 11 via a pipe 23, and an opening / closing valve 24 and a flow rate regulator are provided at the original parts of the pipe 23 on the nitrogen gas supply unit 20 and the cleaning device main body 11 side. 25 is arranged. Between the on-off valve 24 and the flow rate regulator 25 of the pipe 23, the other end of the pipe 26 and the pipe 27, one end of which is connected to the hydrogen fluoride gas supply unit 21 and the organic solvent vapor supply unit 22, is connected. Yes. Further, the pipe 26 and the pipe 27 are provided with an on-off valve 28 and an on-off valve 29, respectively.

  The liquid system supply pipe system 14 includes a pipe 31, an organic acid chemical liquid supply unit 32, an ozone water supply unit 33, and a pure water supply unit 34. One end of the pipe 31 communicates with a nozzle in the cleaning apparatus main body 11, and the other end portion branches into three and is connected to an organic acid chemical solution supply unit 32, an ozone water supply unit 33, and a pure water supply unit 34, respectively. Is done. Further, flow rate regulators 35, 36, and 37 are disposed at the three branches of the pipe 31, respectively.

  As shown in FIG. 2, the cleaning processing chamber 40 in the cleaning apparatus main body 11 has a stage 42 for loading a wafer 41. The stage 42 includes a wafer support portion 43 that supports the wafer 41 at its end surface, and a shaft 44 that extends downward from the lower center of the stage. The shaft 44 is connected to a rotary motor (not shown), and the stage 42 can be rotated at an arbitrary speed by rotational driving of the motor. In addition, the piping 17 communicates with the cleaning processing chamber 40 through the flow rate regulator 18, ozone gas is supplied from the first gas supply pipe system 12, the piping 23 communicates with the flow rate regulator 25, and the second Nitrogen gas, hydrogen fluoride gas, and organic solvent vapor are supplied from the gas supply pipe system 12. Further, a tip of a nozzle 45 connected to the pipe 31 is provided above the wafer 41 in the cleaning processing chamber 40, and ozone water and organic are supplied from the liquid system supply pipe system 14 via the flow rate regulator 35, 36 or 37. An acid chemical solution or pure water is supplied to the upper surface of the wafer. Further, an exhaust pipe 47 for exhausting exhaust gas through an on-off valve 46 and a waste liquid pipe 49 for exhausting waste liquid through an on-off valve 48 communicate with the lower part of the cleaning processing chamber 40.

  Next, the wafer surface cleaning method according to the present invention will be described with reference to FIGS. 3 and 4 in addition to FIGS. FIG. 3 is a flowchart showing a procedure for carrying out the wafer surface purification method according to the present embodiment. FIG. 4 is a diagram for explaining the principle of cleaning the surface of a silicon wafer according to the method of the present invention. FIGS. 4A to 4D are vertical sectional views of a part of the silicon wafer at a predetermined stage of the cleaning process. FIG.

  The silicon wafer surface cleaning method of the present embodiment is performed according to the following procedure. First, the silicon wafer 41 to be cleaned is loaded on the stage 42 in the chamber of the wafer cleaning apparatus 10. Next, the flow rate regulator 18 is operated to introduce ozone gas, which is an oxidizing gas, into the cleaning apparatus body 11 from the ozone gas supply unit 16 through the pipe 17, and this is brought into contact with the surface of the wafer 41. A first surface layer reforming process for forming an oxide film (first oxide film) on the surface layer including the wafer surface is performed (step S1).

  As shown in FIG. 4A, after the first surface layer reforming process, the surface layer including the surface of the silicon wafer 41 to which the fine particles 52 are fixed becomes the oxide film 53 which is the first oxide film. . As the ozone gas 54, which is a gas, circulates below the fine particles 52, an oxide film is also formed below the fine particles 52.

The concentration when ozone gas is used as the gas having an oxidizing action is preferably 50 to 300 g / m ³ . When the concentration of ozone gas is lower than 50 g / m ^3, an oxide film having a sufficient thickness is not formed on the wafer surface, and when it is higher than 300 g / m ³ , the surface state may be deteriorated. Moreover, the time for supplying ozone gas to the wafer cleaning apparatus is preferably 5 seconds or more. If the gas supply time is shorter than 5 seconds, an oxide film having a sufficient thickness may not be formed on the wafer surface. Here, it is desirable to form an oxide film of 10 mm or more from the viewpoint of securing the separation distance between the fine particles and the wafer in the next etching process.

  Next, the ozone gas is cleaned through the exhaust pipe 47 by operating the on-off valve 24 and the flow rate regulator 25 to introduce nitrogen gas into the cleaning processing chamber 40 from the nitrogen gas supply unit 20 through the pipe 23. The gas is discharged from the processing chamber 40. Thereafter, a hydrogen fluoride-containing gas, which is an etching gas, is introduced from the hydrogen fluoride gas supply unit 21 through the pipes 26 and 23 into the cleaning processing chamber 40 and is brought into contact with the surface of the silicon wafer 41. A surface layer removing step is performed to remove the oxide film on the wafer by etching (step S2). As a result, the fine particles 52 are separated (lifted off) from the silicon wafer 41 as shown in FIG.

  An anhydrous hydrogen fluoride gas is preferably used as the gas having an etching action. Hydrogen fluoride gas is mixed with nitrogen gas and supplied, and the gas concentration is preferably 1000 to 400,000 ppm. When the gas concentration of the hydrogen fluoride gas is lower than 1000 ppm, the oxide film on the wafer surface is not easily etched, and when it is higher than 400000 ppm, the corrosivity becomes high. The ppm at this time represents a volume ratio, and 10000 ppm is 1 vol%. Further, the time for supplying the hydrogen fluoride gas to the wafer cleaning apparatus is preferably 10 seconds or more. If the gas supply time is shorter than 10 seconds, it is difficult to sufficiently remove the oxide film on the wafer surface by etching.

  In addition, the drying effect can be enhanced by adding methanol, ethanol, or isopropyl alcohol vapor to the hydrogen fluoride gas. The hydrogen fluoride-containing gas contains citric acid gas or oxalic acid gas. By doing so, the potential of the fine particles 52 is stabilized, and the removal effect of the fine particles 52 can be enhanced. These organic solvent gases are supplied from the organic solvent vapor supply unit 22 to the cleaning processing chamber 40 via the pipes 27 and 23.

  Further, in the hydrogen fluoride gas atmosphere introduced in step 2, while rotating the stage 42 loaded with the silicon wafer 41, the organic acid chemical solution supply unit 32 passes the pipe 31 and the nozzle 45 to the silicon wafer 41. A wafer surface rinsing process is performed by supplying an organic acid chemical (step S3). This prevents re-adhesion of the fine particles and removes the metal particles.

  Organic acid chemicals include oxalic acid, citric acid, succinic acid, ethylenediaminetetraacetic acid, tartaric acid, salicylic acid, formic acid, maleic acid, propionic acid, acetic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, benzoic acid It is preferable to use acrylic acid, adipic acid, malonic acid, malic acid, glycolic acid, phthalic acid, terephthalic acid or fumaric acid. In particular, from the viewpoint of improving the removal effect of the metal particles on the wafer surface, it is desirable to use a non-ionic dicarboxylic acid having a potential, and it is preferable to use oxalic acid or citric acid.

  The rinsing process on the wafer surface using a chemical solution of an organic acid can be omitted. Even without this step, the fine particles from the silicon wafer 41 can be removed by the next second surface layer reforming step. By adding the organic acid rinsing step, it becomes possible to more effectively enhance the removal action of the metal fine particles from the wafer surface due to the chelating effect of the organic acid.

  Next, nitrogen gas is introduced into the cleaning processing chamber 40 from the nitrogen gas supply unit 20 through the pipe 23, and the hydrogen fluoride-containing gas is discharged from the cleaning processing chamber 40 through the exhaust pipe 47. Thereafter, while rotating the stage 42 loaded with the silicon wafer 41, the second surface layer that supplies ozone water, which is a chemical solution having an oxidizing action, from the ozone water supply unit 33 to the silicon wafer 41 through the pipe 31 and the nozzle 45. A reforming process is performed (step S4).

  As shown in FIG. 4C, the surface of the wafer was cleaned by supplying ozone water 56 onto the wafer 41, and the fine particles 52 remaining on the silicon wafer 41 after Step 3 or Step 3 was omitted. In this case, the fine particles 52 separated from the silicon wafer 41 in step S2 are removed from the surface of the silicon wafer 41, and a second oxide film is formed on the surface layer portion of the silicon wafer 41 as shown in FIG. An oxide film 57 is formed.

  When the concentration of ozone water is lower than 0.5 ppm, the ozone aqueous solution used as a chemical solution having an oxidizing action is difficult to remove fine particles sufficiently, and the solubility limit of ozone in pure water is about 25 ppm. It is desirable that the water concentration is 0.5 to 25 ppm. The ppm at this time represents a weight ratio, and 10000 ppm is 1 wt%.

  Further, after the second surface layer reforming process, pure water is supplied onto the silicon wafer 41 from the pure water supply unit 34 via the pipe 31 and the nozzle 45 while rotating the silicon wafer 41 in the cleaning processing chamber 40. Then, a rinsing process for cleaning the wafer surface is performed (step S5). Thereafter, a drying process for drying the wafer is performed by increasing the rotational speed of the silicon wafer 41, shaking off pure water by centrifugal force, and heating the temperature in the cleaning chamber 40 (step S6). In addition, the rinse process of step S5 can be omitted.

  As described above, according to the present embodiment, the surface layer including the wafer surface is oxidized with ozone gas having an oxidizing action, and the oxide film is etched with a hydrogen fluoride-containing gas having an etching action, whereby a liquid is obtained. In this case, it becomes possible to form and remove minute recesses on the wafer surface and the back side of the fine particles, which are difficult to reach, and to effectively separate the fine particles adhering to the wafer from the wafer surface. Furthermore, the protective film can be formed on the wafer surface by simultaneously removing the fine particles separated from the wafer surface and making the wafer surface hydrophilic using ozone water having an oxidizing action. With this technique, it is possible to efficiently remove small-sized fine particles that were difficult to remove with the conventional technique, and it is possible to provide a wafer with less residual fine particles and higher surface quality.

  In other words, it is possible to remove particles more effectively by synthesizing the separation of fine particles from the wafer by the formation of an oxide film using gas and the etching using gas, and the cleaning of the wafer by an oxidizing chemical solution. ing.

  Further, by reducing the number of steps using liquid, the amount of chemical solution and pure water used can be reduced, and the cost related to the cleaning step can be reduced. Furthermore, by cleaning the wafer surface with a chemical solution of an organic acid between the surface layer removal step and the second surface layer modification treatment step, the metal fine particles can be more effectively removed.

  It should be noted that the present invention is not limited to the above embodiment, and many changes or modifications are possible. For example, in the above description, wafer cleaning is performed using a single wafer cleaning apparatus, but the present invention is not limited to this, and can be applied to a batch cleaning apparatus. In addition, although ozone gas is used as the gas having an oxidizing action, the gas is not limited thereto, and the gas having an etching action is a hydrogen fluoride-containing gas, but is not limited thereto. Furthermore, although ozone water is used as the chemical solution having an oxidizing action, it is not limited to this, and hydrogen peroxide water or the like can also be used.

  Hereinafter, the result of verifying the effect of the method according to the present invention by comparing the cleaning result of the wafer to which the silicon wafer surface cleaning method according to the present invention is applied with the cleaning result of the silicon wafer based on the conventional method will be shown.

Example 1
In the first embodiment, the processing conditions of the steps S1, S2, and S4 are set as follows, and the steps S1, S2, S4-S6 are executed without performing step S3 to clean the surface of a wafer having a diameter of 300 mm. went.
Step 1: First surface layer reforming process Gas used: Ozone gas Wafer temperature: 25 ° C
Ozone gas concentration: 200 g / m ³
Gas supply time: 30 seconds Step 2: Surface layer removal process Gas used: Hydrogen fluoride gas Wafer temperature: 25 ° C
Concentration of hydrogen fluoride gas: 10000 ppm (1 vol%) (remainder N ₂ )
Gas supply time: 15 seconds Step 4: Second surface layer modification treatment process Chemical solution used: Ozone water Wafer temperature: 25 ° C
Concentration of ozone water: 10ppm (0.001wt%)
Liquid supply time: 30 seconds

(Example 2)
The surface layer of the wafer was purified under the condition that the hydrogen fluoride gas in the surface layer removing step of Step 2 of Example 1 was replaced with anhydrous hydrogen fluoride gas. The concentration of anhydrous hydrogen fluoride gas was 1 vol%. Other conditions were the same as in Example 1.

(Example 3)
The surface of the wafer was cleaned by replacing the hydrogen fluoride gas in the surface layer removing step of Step 2 of Example 1 with a mixed gas of hydrogen fluoride gas and isopropyl alcohol vapor. The concentration of the mixed gas at this time was 15000 ppm. Other conditions were the same as in Example 1.

Example 4
As a chemical solution having an oxidizing action in Step 4 of Example 1, the wafer surface was cleaned using hydrogen peroxide water instead of ozone water. The concentration of the hydrogen peroxide solution at this time was 3 wt%. Other conditions were the same as in Example 1.

(Example 5)
The wafer surface was cleaned by adding the organic acid rinsing process of Step 3 between Step 2 and Step 4 of Example 1. Other conditions were the same as in Example 1. As the organic acid chemical used, oxalic acid having a concentration of 0.05 wt% was used.

(Comparative Example 1)
Ozone water and hydrofluoric acid water were alternately supplied to the wafer surface to remove fine particles on the wafer surface. At this time, treatment was performed by alternately supplying each chemical solution three times for 10 seconds using ozone water having a concentration of 10 ppm (0.001 wt%) and hydrofluoric acid water having a concentration of 3 wt%.

(Comparative Example 2)
According to Cited Document 1, an oxidizing gas and a wafer are brought into contact with each other to form an oxide film on the wafer surface. Thereafter, the wafer is brought into contact with a mixed vapor of organic solvent vapor and water vapor, and a mixed vapor liquid is formed on the wafer. With the film formed, an etching gas was brought into contact with the wafer to etch and remove the oxide film. At this time, an oxide film is first formed on the wafer surface by treatment with ozone gas having a concentration of 100 g / m ³ for 10 seconds, and then a mixed gas of water vapor having a concentration of 50 vol% and vapor of isopropyl alcohol having a concentration of 20 vol% is used. A liquid film was formed on the surface by contact with the wafer for 2 seconds, and then treated with hydrogen fluoride gas having a concentration of 20 vol% for 10 seconds to etch and remove the oxide film.

  In each of the above Examples and Comparative Examples, the organic fine particles of 50 nm or more remaining on the wafer surface and the density of copper atoms were measured. The measurement results are summarized in Table 1.

  As shown in Table 1, in Example 1-5, an excellent fine particle removal effect was obtained compared to Comparative Examples 1 and 2. Furthermore, in Example 5 including the organic acid rinsing step, an excellent metal fine particle removing effect was obtained as compared with Example 1.

  According to the present invention, an oxidizing gas is brought into contact with the wafer surface, the surface layer including the wafer surface is used as the first oxide film, and then an etching gas is brought into contact with the wafer surface to Since the oxide film is removed, and the fine particles remaining on the wafer surface are removed and the second oxide film is formed using an oxidizing chemical solution, the wafer surface can be used with a small amount of chemicals used. Fine particles such as organic substances and metals adhering to the surface can be removed so that there are fewer residual fine particles.

DESCRIPTION OF SYMBOLS 10 Wafer cleaning apparatus 11 Cleaning apparatus main body 12 1st gas supply pipe system 13 2nd gas supply pipe system 14 Liquid system supply pipe system 16 Ozone gas supply part 17 Piping 18 Flow controller 20 Nitrogen gas supply part 21 Hydrogen fluoride gas supply part DESCRIPTION OF SYMBOLS 22 Organic solvent vapor | steam supply part 23 Piping 24 Open / close valve 25 Flow controller 26, 27 Pipe 28, 29 Open / close valve 31 Pipe 32 Organic acid chemical supply part 33 Ozone water supply part 34 Pure water supply part 35, 36, 37 Flow controller 40 Cleaning Processing Chamber 41 Silicon Wafer 42 Stage 43 Wafer Support 44 Shaft 45 Nozzle 46 On-off Valve 47 Exhaust Line 48 On-Off Valve 49 Waste Liquid Line 52 Fine Particle 53 Oxide Film 54 Ozone Gas 55 Hydrogen Fluoride Gas 56 Ozone Water 57 Oxide Film

Claims (9)

A first surface layer reforming process in which an oxidizing gas is brought into contact with the surface of the silicon wafer, and the surface layer including the wafer surface is used as a first oxide film;
A surface layer removing step of contacting the wafer surface with an etching gas to remove the first oxide film;
A second surface layer modification treatment step of contacting a chemical solution having an oxidizing action with the wafer surface from which the first oxide film has been removed to remove fine particles remaining on the wafer surface and to form a second oxide film; A method for cleaning a surface of a silicon wafer, comprising:   The silicon wafer surface purification method according to claim 1, wherein the oxidizing gas is ozone gas.   The method for cleaning the surface of a silicon wafer according to claim 1 or 2, wherein the gas having an etching action is a gas containing hydrogen fluoride.   The method of claim 3, wherein the hydrogen fluoride-containing gas further contains methanol, ethanol, or isopropyl alcohol vapor.   5. The method for cleaning a surface of a silicon wafer according to claim 3, wherein the hydrogen fluoride-containing gas further contains citric acid gas or oxalic acid gas.   6. The method for cleaning a surface of a silicon wafer according to claim 1, wherein the chemical liquid having an oxidizing action is ozone water or hydrogen peroxide water.   7. The method according to claim 1, further comprising a pure water rinsing step of cleaning the silicon wafer with pure water and a drying step of drying the cleaned silicon wafer following the second surface layer modification treatment step. The method for cleaning the surface of a silicon wafer according to any one of the above.   The method further comprises an organic acid rinsing step of cleaning the wafer surface using an organic acid chemical solution to remove metal particles between the surface layer removal step and the second surface layer modification treatment step. The surface purification method of the silicon wafer of any one of Claims 1-7.   The organic acid chemical solution is oxalic acid, citric acid, succinic acid, ethylenediaminetetraacetic acid, tartaric acid, salicylic acid, formic acid, maleic acid, propionic acid, acetic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, benzoic acid 9. The method of cleaning a surface of a silicon wafer according to claim 8, wherein the surface purification method is acrylic acid, adipic acid, malonic acid, malic acid, glycolic acid, phthalic acid, terephthalic acid or fumaric acid.

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