Silicon wafer cleaning etching solution and application thereof in inhibiting surface oxidation of silicon wafer

Abstract

The invention relates to the technical field of electronic chemicals, and particularly discloses a silicon wafer cleaning etching solution and application thereof in inhibiting surface oxidation of a silicon wafer, the etching solution comprises the following components in percentage by mass: 0-10% of hydrofluoric acid, 0-30% of ammonium fluoride, 0.001-1% of an additive and the balance of water; the additive is a compound containing olefin and amide. According to the invention, hydrofluoric acid and ammonium fluoride form a cleaning system, meanwhile, a compound containing olefin and amide is introduced as an additive, and free radical groups on the surface of the silicon wafer are modified, so that natural oxidation of the surface of the cleaned silicon wafer can be effectively inhibited, and the stability and precision of a subsequent manufacturing process are ensured.

Description

Technical Field

[0001] The invention relates to the technical field of electronic chemicals, and in particular to a silicon wafer cleaning etching solution and application thereof in inhibiting silicon wafer surface oxidation. Background Art

[0002] Functional electronic chemicals refer to special chemicals supporting the electronics industry, which are commonly used in the cleaning and etching processes during the manufacturing process of integrated circuit structures. Chemicals for wet cleaning and etching have high quality requirements, strong functionality and high product precision.

[0003] With the rapid development of integrated circuits, the manufacturing precision requirements for the GATE area of ​​IGBT and MOSFET processes are getting higher and higher. With the increase in manufacturing line width, the natural oxide layer has a significant impact on the electrical signal conduction of the chip. It is becoming more and more important to avoid the natural oxidation of silicon wafers, which is a critical link for the reliability of microelectronic integrated circuits. Summary of the invention

[0004] The invention provides a silicon wafer cleaning etching solution and application thereof in inhibiting silicon wafer surface oxidation. The etching solution is used for cleaning the surface oxide layer of base silicon in semiconductor manufacturing and can effectively inhibit the natural oxidation of the silicon wafer surface after cleaning.

[0005] The technical solution of the present invention is to provide a silicon wafer cleaning etching solution, which contains 0.1-10% hydrofluoric acid, 1-30% ammonium fluoride and 0.001-0.5% additives in terms of mass percentage, and the rest is water; the additive is a compound containing olefins and amides.

[0006] Optionally, the hydrofluoric acid content is 0.1-5% by mass.

[0007] Optionally, the hydrofluoric acid is electronic grade with a mass concentration of 48-50%.

[0008] Optionally, the ammonium fluoride content is 1-20% by mass.

[0009] Optionally, the ammonium fluoride is electronic grade with a mass concentration of 48-50%.

[0010] Optionally, the compound containing olefin and amide is any one or a combination of butenamide, octenamide, dodecenamide, undec-10-enamide, and arachidonic acid amide.

[0011] Optionally, the additive is added in an amount of 0.05-0.2%.

[0012] Optionally, the water is ultrapure water with a resistivity of ≥18 megohms at 25°C.

[0013] The invention also relates to the application of the silicon wafer cleaning etching solution in inhibiting the natural oxidation of the surface of the silicon wafer after cleaning.

[0014] The present invention has the following beneficial effects: The cleaning system is composed of hydrofluoric acid and ammonium fluoride, wherein the hydrofluoric acid is used to clean the oxide layer film; the ammonium fluoride is used to provide a fluorine ion-stabilized etching solution for cleaning, which can effectively remove impurities and the oxide layer on the surface of the silicon wafer; and at the same time, compounds containing olefins and amides are introduced into the cleaning etching solution as additives, which can effectively inhibit the natural oxidation of the surface of the silicon wafer after cleaning by modifying the free radicals on the surface of the silicon wafer, thereby ensuring the stability and accuracy of the subsequent manufacturing process. DETAILED DESCRIPTION

[0015] The experimental methods in the following examples are conventional methods unless otherwise specified. The raw materials, reagents, etc. used in the following examples are commercially available products unless otherwise specified.

[0016] The invention provides a silicon wafer cleaning etching solution, which contains, by mass percentage, 0.1-10% of hydrofluoric acid, 1-30% of ammonium fluoride and 0.001-0.5% of an additive, and the remainder is water; the additive is a compound containing olefins and amides.

[0017] The hydrofluoric acid is electronic grade with a mass concentration of 48-50%; the etching solution preferably contains 0.1-5% hydrofluoric acid. The ammonium fluoride is electronic grade with a mass concentration of 48-50%. The etching solution preferably contains 1-20% ammonium fluoride. Specifically, the compound containing olefins and amides is preferably any one or a combination of butyleneamide, octenylamide, dodecenylamide, undecyl-10-enylamide, and arachidonic acid amide, and the added amount is preferably 0.05-0.2%.

[0018] The water is ultrapure water, and the resistivity at 25°C is ≥18 megohms.

[0019] The present invention is described in detail below in conjunction with specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and a specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0020] Example 1 The composition of the silicon wafer cleaning etching solution is: 0.5wt% hydrofluoric acid, 5wt% ammonium fluoride, 0.1wt% octenylamide, and the balance is water.

[0021] Example 2 The composition of the silicon wafer cleaning etching solution is: 1wt% hydrofluoric acid, 5wt% ammonium fluoride, 0.1wt% octenylamide, and the balance is water.

[0022] Example 3 The composition of the silicon wafer cleaning etching solution is: 0.5wt% hydrofluoric acid, 10wt% ammonium fluoride, 0.1wt% octenylamide, and the balance is water.

[0023] Example 4 The composition of the silicon wafer cleaning etching solution is: 0.5wt% hydrofluoric acid, 5wt% ammonium fluoride, 0.05wt% dodecenamide, and the balance is water.

[0024] Example 5 The composition of the silicon wafer cleaning etching solution is: 0.5wt% hydrofluoric acid, 5wt% ammonium fluoride, 0.2wt% crotonamide, and the balance is water.

[0025] Example 6 The composition of the silicon wafer cleaning etching solution is: 0.5wt% hydrofluoric acid, 5wt% ammonium fluoride, 0.1wt% arachidonic acid amide, and the balance is water.

[0026] Comparative Example 7 The composition of the silicon wafer cleaning etching solution is: 0.5wt% hydrofluoric acid, 5wt% ammonium fluoride, 1wt% arachidonic acid amide, and the balance is water.

[0027] Comparative Example 8 The composition of the silicon wafer cleaning etching solution is: 15wt% hydrofluoric acid, 5wt% ammonium fluoride, 0.1wt% crotonamide, and the balance is water.

[0028] Comparative Example 9 The composition of the silicon wafer cleaning etching solution is: 0.5wt% hydrofluoric acid, 35wt% ammonium fluoride, 0.1wt% octenylamide, and the balance is water.

[0029] Comparative Example 10 The composition of the silicon wafer cleaning etching solution is: 0.5wt% hydrofluoric acid, 5wt% ammonium fluoride, 0.1wt% butene, and the balance is water.

[0030] Comparative Example 11 The composition of the silicon wafer cleaning and etching solution is: 0.5wt% hydrofluoric acid, 5wt% ammonium fluoride, and the balance is water.

[0031] The above embodiments and comparative examples were used for silicon wafer cleaning tests. A 5*5 cm Si wafer was immersed in 500 ml of cleaning and etching solution for 30 minutes, then taken out for water washing and nitrogen drying. After being placed in a natural environment for 2 hours, the thickness of the natural oxide layer on its surface was measured by an ellipsometer. The specific results are shown in Table 1.

[0032] Table 1 Table 1. Thickness of natural oxide layer on the surface of silicon wafer after cleaning

[0033] It can be seen from Table 1 that after the etching solution in Examples 1-6 cleans the silicon wafer, the initial surface oxide layer thickness is 0.01 nm, and the thickness change of the natural oxide layer after being placed for 2 hours does not exceed 0.15 nm; although the natural oxide layer changes very little in Comparative Example 7, the additive is completely dissolved, the solution is turbid, and the cleaning process of the silicon wafer surface is uneven, and there is a problem of uneven surface natural oxide layer; in Comparative Example 8, the etching solution is highly acidic, providing more hydrogen ions to form free radicals on the surface of the silicon wafer, which makes it easier to form natural oxidation later; in Comparative Example 9, because the solution is too alkaline, it corrodes silicon, the surface roughness increases, and the surface oxidation is promoted; in Comparative Example 10, the additive lacks an amide group and fails to inhibit the natural oxidation of the silicon wafer surface; in Comparative Example 11, there is no additive, and the degree of oxidation on the silicon wafer surface after cleaning is the most serious.

[0034] The above embodiments describe the preferred implementation of the present invention, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A silicon wafer cleaning and etching solution, characterized in that: The etching solution contains, by mass percentage, 0.1-10% hydrofluoric acid, 1-30% ammonium fluoride and 0.001-0.5% additives, and the remainder is water; the additives are compounds containing olefins and amides.

2. The etching solution according to claim 1, characterized in that: Calculated by mass percentage, the hydrofluoric acid content is 0.1~5%.

3. The etching solution according to claim 2, characterized in that: The hydrofluoric acid is electronic grade, and the mass concentration is 48-50%.

4. The etching solution according to claim 1, characterized in that: Calculated by mass percentage, the ammonium fluoride content is 1-20%.

5. The etching solution according to claim 4, characterized in that: The ammonium fluoride is electronic grade and has a mass concentration of 48-50%.

6. The etching solution according to any one of claims 1 to 5, characterized in that: The compound containing olefin and amide is any one of butenamide, octenamide, dodecenamide, undec-10-enamide and arachidonic acid amide or a combination of several thereof.

7. The etching solution according to claim 6, characterized in that: The additive is added in an amount of 0.05-0.2%.

8. The etching solution according to claim 1, characterized in that: The water is ultrapure water, and the resistivity at 25° C. is ≥18 megohms.

9. Use of the silicon wafer cleaning etching solution according to any one of claims 1 to 8 in inhibiting natural oxidation of the surface of a silicon wafer after cleaning.

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