Wafer cleaning solution and method for manufacturing the same

Abstract

The present invention provides a wafer cleaning solution and a method for producing the same. [Solution] The wafer cleaning solution comprises a nonionic surfactant, an anionic surfactant, an antibacterial agent, a pH adjuster, and water. The number-average molecular weight of the nonionic surfactant is 3,000 to 6,000. The anionic surfactant is selected from at least one of the group consisting of sodium lauryl sulfate and polyethylene glycol tridecyl ether phosphate. The acid dissociation constant (pKa) of the pH adjuster is 1.38 to 4.76. The antibacterial agent is selected from at least one of the group consisting of kathon, methylisothiazolinone, triclosan, chloroxyllenol, methacrylate oxide decylpyridinium bromide salt, and quaternary ammonium salt compounds.

Description

Technical Field

[0001] The present invention relates to a cleaning liquid and a manufacturing method therefor, and in particular to a wafer cleaning liquid and a manufacturing method therefor. Background Art

[0002] Existing wafer cleaning liquids usually have excessively high viscosity, which makes the wafer cleaning liquid easily adhere to the wafer surface. Furthermore, existing wafer cleaning liquids usually contain highly corrosive components such as hydrofluoric acid and sulfuric acid, which readily corrode metal circuits on wafers. Summary of the Invention Problems to be Solved by the Invention

[0003] The technical problem to be solved by the present invention is, in view of the deficiencies of the prior art, to provide a wafer cleaning liquid and a manufacturing method therefor that can efficiently solve the problems that the viscosity of conventional wafer cleaning liquids is excessively high and the corrosiveness thereof is excessively strong. Means for Solving the Problems

[0004] To solve the above technical problems, one of the technical means employed by the present invention is to provide a wafer cleaning solution. The wafer cleaning solution comprises a nonionic surfactant having a number average molecular weight of 3,000 to 6,000, an anionic surfactant, a pH adjuster having an acid dissociation constant (pKa) of 1.38 to 4.76, an antibacterial agent, and water, wherein the anionic surfactant is sodium lauryl sulfate and polyethylene glycol tridecyl ether phosphate. The antimicrobial agent is selected from at least one of the group consisting of phosphate, and the antimicrobial agent is selected from at least one of the group consisting of kathon, methylisothiazolinone, triclosan, chloroxyllenol, methacrylate oxide decylpyridinium bromide salt, and quaternary ammonium salt compounds. The total weight of the wafer cleaning solution is 100 wt%, the content of the nonionic surfactant is 1 wt% to 10 wt%, the content of the anionic surfactant is 1 wt% to 10 wt%, the content of the pH adjuster is 0.1 wt% to 5 wt%, the content of the antimicrobial agent is 0.1 wt% to 5 wt%, the water content is 70 wt% to 90 wt%, the viscosity of the wafer cleaning solution is 10 cps to 18 cps, and the pH value of the wafer cleaning solution is 4 to 5.

[0005] Preferably, the nonionic surfactant is polyethylene glycol.

[0006] Preferably, the pH adjusting agent is selected from at least one of the group consisting of citric acid, acetic acid, and oxalic acid.

[0007] Preferably, the wafer cleaning solution further comprises a coolant, the coolant being selected from at least one of the group consisting of ethylene glycol and diethylene glycol, and the coolant content is 5 wt% to 20 wt% with respect to the total weight of the wafer cleaning solution being 100 wt%.

[0008] Preferably, the conductivity of the wafer cleaning solution is 528 μS / cm~550 μSThe surface tension of the wafer cleaning solution is 25 dyne / cm to 30 dyne / cm.

[0009] To solve the above technical problems, another technical means employed by the present invention provides a method for manufacturing a wafer cleaning solution. The method for manufacturing a wafer cleaning solution includes: a first mixing step of obtaining a first solution by adding a nonionic surfactant and an anionic surfactant having a number average molecular weight of 3,000 to 6,000 to water and stirring continuously for 20 to 40 minutes at a first stirring speed of 60 rpm to 100 rpm; a second mixing step of obtaining a second solution by adding an antibacterial agent to the first solution and stirring continuously for 5 to 25 minutes at a second stirring speed of 40 rpm to 80 rpm; and a pH value adjustment step of obtaining a wafer cleaning solution by adding a pH adjusting agent having an acid dissociation constant (pKa) of 1.38 to 4.76 to the second solution and stirring at a third stirring speed of 30 rpm to 70 rpm, wherein the anionic surfactant is sodium lauryl sulfate and polyethylene glycol tridecyl ether phosphate. The antimicrobial agent is selected from at least one of the group consisting of acid esters, and is selected from at least one of the group consisting of kathon, methylisothiazolinone, triclosan, chloroxyllenol, methacrylate oxide decylpyridinium bromide salt, and quaternary ammonium salt compounds. The total weight of the wafer cleaning solution is 100 wt%, the content of the nonionic surfactant is 1 wt% to 10 wt%, the content of the anionic surfactant is 1 wt% to 10 wt%, the content of the pH adjuster is 0.1 wt% to 5 wt%, the content of the antimicrobial agent is 0.1 wt% to 5 wt%, the water content is 70 wt% to 90 wt%, the viscosity of the wafer cleaning solution is 10 cps to 18 cps, and the pH value of the wafer cleaning solution is 4 to 5.

[0010] Preferably, the nonionic surfactant is polyethylene glycol.

[0011] Preferably, the pH adjusting agent is selected from at least one of the group consisting of citric acid, acetic acid, and oxalic acid.

[0012] Preferably, in the first mixing step, a coolant is further added, the coolant being selected from at least one of the group consisting of ethylene glycol and diethylene glycol, and the coolant content is 5 wt% to 20 wt% with respect to the total weight of the wafer cleaning solution being 100 wt%.

[0013] Preferably, the conductivity of the wafer cleaning solution is 528 μS / cm~550 μS The surface tension of the wafer cleaning solution is 25 dyne / cm to 30 dyne / cm. [Effects of the Invention]

[0014] One of the advantageous effects of the present invention is that the wafer cleaning solution and its manufacturing method according to the present invention can efficiently solve problems such as the excessive viscosity and corrosiveness of conventional wafer cleaning solutions, due to technical features such as "the anionic surfactant is selected from at least one of the group consisting of sodium lauryl sulfate and polyethylene glycol tridecyl ether phosphate" and "the acid dissociation constant (pKa) of the pH adjuster is 1.38 to 4.76". [Brief explanation of the drawing]

[0015] [Fig. 1] This is a flowchart of a method for manufacturing a wafer cleaning solution according to an embodiment of the present invention. [Modes for carrying out the invention]

[0016] To further understand the features and technical details of this invention, please refer to the following detailed description of the invention and the accompanying drawings. However, the accompanying drawings provided are for reference and illustrative purposes only and do not limit the scope of the claims of this invention.

[0017] The following describes how the "wafer cleaning solution and method for manufacturing the same" according to the present invention can be implemented by specific embodiments, and those skilled in the art will be able to understand the advantages and effects of the present invention based on the contents disclosed herein. The present invention can be implemented or applied by other different specific embodiments, and various modifications and changes can be made to each detail herein, based on different viewpoints and applications, as long as they do not deviate from the concept of the present invention. It should be noted in advance that the accompanying drawings of the present invention are for simple schematic explanation and are not drawn to actual size. The technical content of the present invention will be described in more detail below based on embodiments, but the scope of protection of the present invention is not limited by the contents disclosed.

[0018] It should be understood that while this specification may use terms such as “first,” “second,” and “third” to describe various elements or signals, these elements or signals are not limited by these terms. These terms are primarily used to distinguish one element from another, or one signal from another. Furthermore, the term “or” as used herein may, depending on the context, include any one or more of the items listed in relation to the subject.

[0019] [Wafer cleaning solution] In embodiments of the present invention, a wafer cleaning solution is disclosed. The wafer cleaning solution comprises a nonionic surfactant, an anionic surfactant, a pH adjuster, an antimicrobial agent, and water. Naturally, the wafer cleaning solution may contain other components as needed, but the present invention is not limited thereto. The wafer cleaning solution is used to clean a cut wafer and remove impurities generated by the wafer cutting, but the present invention is not limited thereto.

[0020] The viscosity of said wafer cleaning solution is 10 cps to 18 cps, and the pH value of said wafer cleaning solution is 4 to 5. Preferably, the viscosity of said wafer cleaning solution is 15 cps to 16 cps, and the pH value of said wafer cleaning solution is 4.2 to 4.6. The viscosity and pH value of said wafer cleaning solution may, for example, be measured at normal temperature (such as 25°C).

[0021] Based on 100 wt% of the total weight of said wafer cleaning solution, the content of said nonionic surfactant is 1 wt% to 10 wt%, the content of said anionic surfactant is 1 wt% to 10 wt%, the content of said pH adjuster is 0.1 wt% to 5 wt%, the content of said antibacterial agent is 0.1 wt% to 5 wt%, and the content of water is 70 wt% to 90 wt%.

[0022] The number average molecular weight of said nonionic surfactant is 3,000 to 6,000. It should be explained that if the number average molecular weight of said nonionic surfactant is too low, the chain length of the nonionic surfactant will be too short, making it impossible to effectively cover impurities on the wafer. On the other hand, if the number average molecular weight of said nonionic surfactant is too high, the viscosity of said wafer cleaning solution will be too high, and it will easily adhere to the surface of the wafer. Preferably, the number average molecular weight of said nonionic surfactant is 3,000 to 5,000. More preferably, the number average molecular weight of said nonionic surfactant is about 4,000. In this embodiment, said nonionic surfactant is polyethylene glycol, but the present invention is not limited thereto.

[0023] Said anionic surfactant is used for adjusting properties of said wafer cleaning solution (such as surface tension, viscosity and electrical conductivity, etc.). Said anionic surfactant is selected from at least one of the group consisting of sodium lauryl sulfate and polyethylene glycol tridecyl ether phosphate. The number average molecular weight of polyethylene glycol tridecyl ether phosphate may be 300 to 700, but the present invention is not limited thereto.

[0024] The pH adjusting agent is an organic weak acid, and the acid dissociation constant (pKa) of said pH adjusting agent is 1.38 to 4.76. The acid dissociation constant of said pH adjusting agent may be measured at normal temperature (such as 25°C). In this embodiment, said pH adjusting agent is selected from at least one member selected from the group consisting of citric acid, acetic acid and oxalic acid, but the present invention is not limited thereto. With said pH adjusting agent, the pH value of said wafer cleaning solution is 4 to 5, whereby said wafer cleaning solution is less likely to corrode metal circuits on the wafer.

[0025] Said antibacterial agent is selected from at least one member selected from the group consisting of Kathon, methylisothiazolinone, triclosan, chloroxylenol, methacryloyloxydodecylpyridinium bromide, and quaternary ammonium salt compounds. Said antibacterial agent can exert an antibacterial effect even in a weakly acidic environment.

[0026] Said wafer cleaning solution may further comprise a cooling agent, and said cooling agent is selected from at least one member selected from the group consisting of ethylene glycol and diethylene glycol. Based on 100 wt% of the total weight of said wafer cleaning solution, the content of said cooling agent is 5 wt% to 20 wt%.

[0027] The electrical conductivity of said wafer cleaning solution may be 528 μS / cm to 550 μS / cm, the surface tension of said wafer cleaning solution may be 25 dyne / cm to 30 dyne / cm, and the specific gravity of said wafer cleaning solution may be 1.01 to 1.02, but the present invention is not limited thereto. The electrical conductivity and surface tension of said wafer cleaning solution may be measured at normal temperature (such as 25°C). If the electrical conductivity of said wafer cleaning solution is too high, a short circuit may occur in the metal circuit of the wafer. If the surface tension of the wafer cleaning solution is too high, the wafer cleaning solution is likely to remain on the wafer surface.

[0028] [Method for manufacturing wafer cleaning solution] The present invention further provides a method for manufacturing a wafer cleaning solution. The wafer cleaning solution described above is obtained by performing the wafer cleaning solution manufacturing method described above, but the present invention is not limited thereto. The wafer cleaning solution manufacturing method includes a first mixing step S110, a second mixing step S120, and a pH value adjustment step S130. Naturally, the wafer cleaning solution manufacturing method may include other steps as needed, but the present invention is not limited thereto.

[0029] In the first mixing step S110, a nonionic surfactant and an anionic surfactant having a number average molecular weight of 3,000 to 6,000 are added to water, and the mixture is stirred continuously for 20 to 40 minutes at a first stirring speed of 60 rpm to 100 rpm to obtain a first solution. The anionic surfactant is selected from at least one of the group consisting of sodium lauryl sulfate and polyethylene glycol tridecyl ether phosphate. The nonionic surfactant may be polyethylene glycol, for example, but the present invention is not limited thereto.

[0030] In the second mixing step S120, an antimicrobial agent is added to the first solution and the mixture is stirred continuously for 5 to 25 minutes at a second stirring speed of 40 rpm to 80 rpm to obtain a second solution. The antimicrobial agent is selected from at least one of the group consisting of kathon, methylisothiazolinone, triclosan, chloroxyllenol, methacrylate oxide decylpyridinium bromide salt, and quaternary ammonium salt compounds.

[0031] In the pH value adjustment step S130, a pH adjusting agent is added to the second solution and stirred at a third stirring speed of 30 rpm to 70 rpm to obtain a wafer cleaning solution. The pH adjusting agent is an organic weak acid, and the acid dissociation constant (pKa) of the pH adjusting agent is 1.38 to 4.76. Preferably, the pH adjusting agent is selected from at least one of the group consisting of citric acid, acetic acid, and oxalic acid.

[0032] Assuming the total weight of the wafer cleaning solution is 100 wt%, the content of the nonionic surfactant is 1 wt% to 10 wt%, the content of the anionic surfactant is 1 wt% to 10 wt%, the content of the pH adjuster is 0.1 wt% to 5 wt%, the content of the antibacterial agent is 0.1 wt% to 5 wt%, and the water content is 70 wt% to 90 wt%.

[0033] In the first mixing step S110, a coolant may be further added, and the coolant is selected from at least one of the group consisting of ethylene glycol and diethylene glycol. The coolant can reduce the thermal energy generated in the first mixing step S110. The coolant content is 5 wt% to 20 wt% when the total weight of the wafer cleaning solution is 100 wt%. In addition, a corrosion inhibitor may be further added in the first mixing step S110, and the corrosion inhibitor may be, for example, benzotriazole, but the present invention is not limited thereto. The corrosion inhibitor content is 0.1 wt% to 5 wt% when the total weight of the wafer cleaning solution is 100 wt%.

[0034] The viscosity of the wafer cleaning solution is 10 cps to 18 cps, and the pH value of the wafer cleaning solution is 4 to 5. Preferably, the conductivity of the wafer cleaning solution is 528. μS / cm~550 μS The surface tension of the wafer cleaning solution is 25 dyne / cm to 30 dyne / cm.

[0035] [Measurement of experimental data] The composition, pH value, viscosity, conductivity, surface tension, solid content, and specific gravity of each component of the wafer cleaning solution in Examples 1-3 and Comparative Examples 1-12 are shown in Table 1 below. The measurement method will be explained below.

[0036] pH value: Measured using a pH meter at a temperature of 25°C.

[0037] Conductivity: Measured using a conductivity meter at a temperature of 25°C.

[0038] Surface tension: Measured using the Wilhelmy plate method (plate method) with a surface tensimeter.

[0039] Solids content: Drying method was used. Solids content (%) = (Mass of solids / Total mass) × 100%.

[0040] Specific gravity: Measured using a hydrometer at a temperature of 25 degrees Celsius.

[0041] [Table 1] TIFF0007918297000001.tif157144

[0042] [Table 2] JPEG0007918297000002.jpg201163

[0043] [Table 3] TIFF0007918297000003.tif140144

[0044] [Table 4] TIFF0007918297000004.tif145144

[0045] [Review of measurement results] In Comparative Example 1, the wafer cleaning solution lacked a pH adjuster, resulting in an excessively high pH value. The wafer cleaning solutions in Comparative Examples 2-5 contained polyvinylpyrrolidone (PVP K30) but not polyethylene glycol. Furthermore, because they contained alkyl polyoxyethylene ether, cellulose, polyoxyethylene polyoxypropylene monobutyl ether, or lauryl polyoxyethylene ether, the pH or conductivity of the wafer cleaning solutions was excessively high. In Comparative Examples 6-8, the number-average molecular weight of polyethylene glycol was too low, while in Comparative Examples 7-9, the molecular weight of the cationic surfactants (also called cationic surfactants) (i.e., hexadecyltrimethylammonium chloride and octadecyltrimethylammonium chloride) was too high, resulting in excessively high viscosity and low conductivity of the wafer cleaning solutions in Comparative Examples 6-9. The wafer cleaning solutions in Comparative Examples 10-12 contained strong inorganic acids, resulting in excessively low pH values.

[0046] [Advantageous effects of the embodiment] One of the advantageous effects of the present invention is that the wafer cleaning solution and its manufacturing method according to the present invention can efficiently solve problems such as the excessive viscosity and corrosiveness of conventional wafer cleaning solutions, due to technical features such as "the anionic surfactant is selected from at least one of the group consisting of sodium lauryl sulfate and polyethylene glycol tridecyl ether phosphate" and "the acid dissociation constant (pKa) of the pH adjuster is 1.38 to 4.76".

[0047] The information disclosed above represents only preferred and implementable embodiments of the present invention, and the claims of the present invention are not limited thereto. Therefore, any equivalent technical modifications made using the description and drawings of the present invention are all included within the scope of the claims of the present invention. [Explanation of symbols]

[0048] S110...First mixing process S120...Second mixing process S130... pH value adjustment process

Claims

1. A wafer cleaning solution comprising a nonionic surfactant having a number average molecular weight of 3,000 to 5,000, an anionic surfactant, a pH adjuster having an acid dissociation constant (pKa) of 1.38 to 4.76 at 25°C, an antibacterial agent, and water, The anionic surfactant is selected from at least one of the group consisting of sodium lauryl sulfate and polyethylene glycol tridecyl ether phosphate. The antibacterial agent is selected from at least one of the group consisting of kathon, methylisothiazolinone, triclosan, chloroxyllenol, methacrylate oxide dodecylpyridinium bromide salt, and quaternary ammonium salt compounds. Assuming the total weight of the wafer cleaning solution is 100 wt%, the content of the nonionic surfactant is 1 wt% to 10 wt%, the content of the anionic surfactant is 1 wt% to 10 wt%, the content of the pH adjuster is 0.1 wt% to 5 wt%, the content of the antibacterial agent is 0.1 wt% to 5 wt%, and the water content is 70 wt% to 90 wt%. A wafer cleaning solution characterized in that the viscosity of the wafer cleaning solution at 25°C is 10 cps to 18 cps, and the pH value of the wafer cleaning solution at 25°C is 4 to 5.

2. The wafer cleaning solution according to claim 1, wherein the nonionic surfactant is polyethylene glycol.

3. The wafer cleaning solution according to claim 1, wherein the pH adjusting agent is selected from at least one of the group consisting of citric acid, acetic acid, and oxalic acid.

4. The wafer cleaning solution according to claim 1, further comprising a coolant, the coolant being selected from at least one of the group consisting of ethylene glycol and diethylene glycol, and with a total weight of 100 wt% of the wafer cleaning solution, the content of the coolant being 5 wt% to 20 wt%.

5. The wafer cleaning solution according to claim 1, wherein the conductivity of the wafer cleaning solution at 25°C is 528 μS / cm to 550 μS / cm, and the surface tension of the wafer cleaning solution at 25°C is 25 dyne / cm to 30 dyne / cm.

6. A first mixing step involves adding a nonionic surfactant and an anionic surfactant having a number-average molecular weight of 3,000 to 5,000 to water and stirring continuously at a first stirring speed of 60 rpm to 100 rpm for 20 to 40 minutes to obtain a first solution. A second mixing step is performed, in which an antibacterial agent is added to the first solution and the mixture is continuously stirred at a second stirring speed of 40 rpm to 80 rpm for 5 to 25 minutes to obtain a second solution. The method includes a pH adjustment step, in which a pH adjusting agent having an acid dissociation constant (pKa) of 1.38 to 4.76 at 25°C is added to the second solution, and the solution is stirred at a third stirring speed of 30 rpm to 70 rpm to obtain a wafer cleaning solution. The anionic surfactant is selected from at least one of the group consisting of sodium lauryl sulfate and polyethylene glycol tridecyl ether phosphate. The antibacterial agent is selected from at least one of the group consisting of kathon, methylisothiazolinone, triclosan, chloroxyllenol, methacrylate oxide dodecylpyridinium bromide salt, and quaternary ammonium salt compounds. Assuming the total weight of the wafer cleaning solution is 100 wt%, the content of the nonionic surfactant is 1 wt% to 10 wt%, the content of the anionic surfactant is 1 wt% to 10 wt%, the content of the pH adjuster is 0.1 wt% to 5 wt%, the content of the antibacterial agent is 0.1 wt% to 5 wt%, and the water content is 70 wt% to 90 wt%. A method for manufacturing a wafer cleaning solution, characterized in that the viscosity of the wafer cleaning solution at 25°C is 10 cps to 18 cps, and the pH value of the wafer cleaning solution at 25°C is 4 to 5.

7. The method for producing a wafer cleaning solution according to claim 6, wherein the nonionic surfactant is polyethylene glycol.

8. The method for producing a wafer cleaning solution according to claim 6, wherein the pH adjusting agent is selected from at least one of the group consisting of citric acid, acetic acid, and oxalic acid.

9. In the first mixing step described above, a coolant is further added, The method for producing a wafer cleaning solution according to claim 6, wherein the coolant is selected from at least one of the group consisting of ethylene glycol and diethylene glycol, and the content of the coolant is 5 wt% to 20 wt% when the total weight of the wafer cleaning solution is 100 wt%.

10. The method for manufacturing a wafer cleaning solution according to claim 6, wherein the conductivity of the wafer cleaning solution at 25°C is 528 μS / cm to 550 μS / cm, and the surface tension of the wafer cleaning solution at 25°C is 25 dyne / cm to 30 dyne / cm.

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