DE-112024002244-T5 - METHOD FOR CLEANING A SEMICONDUCTOR WAFER

Abstract

A method for cleaning a semiconductor wafer is provided that is capable of reducing adhering particles on the surface of the semiconductor wafer. The method of this disclosure comprises, while the semiconductor wafer is being rotated: a first cleaning process for cleaning the semiconductor wafer; a first drying process for drying the semiconductor wafer after the first cleaning process; a second cleaning process for cleaning the semiconductor wafer after the first drying process; and a second drying process for drying the semiconductor wafer after the second cleaning process, wherein the second cleaning process comprises, in the following sequence: a pure water supply process for supplying pure water to the surface of the semiconductor wafer after the first drying process; a second initial ozone cleaning process for supplying an ozone solution to the surface of the semiconductor wafer to perform a cleaning; and a second alternating cleaning process that alternately employs: a second hydrofluoric acid cleaning process for cleaning the surface of the semiconductor wafer with an aqueous solution of hydrofluoric acid; and a second ozone cleaning process to clean the surface with an ozone solution, following the second hydrofluoric acid cleaning process.

Inventors

• Momoka YAMANAKA

Assignees

• SUMCO CORPORATION

Dates

Publication Date

20260513

Application Date

20240111

Priority Date

20230524

Claims (5)

1. A method for cleaning a semiconductor wafer, comprising, while the semiconductor wafer is being rotated: a first cleaning process for cleaning the semiconductor wafer; a first drying process for drying the semiconductor wafer after the first cleaning process; a second cleaning process for cleaning the semiconductor wafer after the first drying process; and a second drying process for drying the semiconductor wafer after the second cleaning process, wherein the first cleaning process comprises, in the following sequence: a first initial ozone cleaning process for supplying an ozone solution to a surface of the semiconductor wafer to perform cleaning; and a first alternating cleaning process, which alternately uses: a first hydrofluoric acid cleaning process for cleaning the surface of the semiconductor wafer with an aqueous solution of hydrofluoric acid; and a first ozone cleaning process for cleaning the surface with an ozone solution, following the first hydrofluoric acid cleaning process, and whereby the second cleaning process comprises, in the following sequence: a purified water supply process for supplying purified water to the surface of the semiconductor wafer after the first drying process; a second initial ozone cleaning process for supplying an ozone solution to the surface of the semiconductor wafer to perform a cleaning; and a second alternating cleaning process, which alternately uses: a second hydrofluoric acid cleaning process for cleaning the surface of the semiconductor wafer with an aqueous solution of hydrofluoric acid; and a second ozone cleaning process for cleaning the surface with an ozone solution, following the second hydrofluoric acid cleaning process.
2. Method for cleaning a semiconductor wafer after Claim 1 , wherein the number of additional cycles of the alternating cleaning process performed in the first cleaning process is not less than one and not more than four.
3. Method for cleaning a semiconductor wafer after Claim 1 or 2 , wherein the number of additional cycles of the alternating cleaning process performed in the first cleaning process is not less than one and not more than two.
4. Method for cleaning a semiconductor wafer after Claim 1 or 3 , where the number of additional cycles performed by the alternating cleaning process in the second cleaning process is one.
5. Method for cleaning a semiconductor wafer after one of the Claims 1 until 4 , wherein the rotational speed of the semiconductor wafer in the pure water feeding process is not less than 25 rpm and not more than 100 rpm.

Description

TECHNICAL AREA The present disclosure relates to a method for cleaning a semiconductor wafer. BACKGROUND Traditionally, semiconductor wafers, such as silicon wafers, have been used as substrates for semiconductor devices. A semiconductor wafer is obtained by subjecting a single-crystal ingot, grown using the Czochralski (CZ) method or similar techniques, to wafer processing. During this processing, particles, such as polishing powder, adhere to the surface of the semiconductor wafer, and therefore a cleaning process is performed on the semiconductor wafer after processing to remove such particles. It is known that in the cleaning process of a semiconductor wafer, particles adhering to the surface of the wafer can be efficiently cleaned and removed by cleaning the wafer surface using various cleaning solutions. For example, patent document 1 discloses a method in which ozone cleaning is carried out by supplying an ozone solution to the surface of the semiconductor wafer, followed by hydrofluoric acid cleaning by supplying hydrofluoric acid to the wafer surface, and then drying of the semiconductor wafer. QUOTE LIST Patent literature PTL 1: JP H8-181137 A Summary (Technical problem) However, in substrates cleaned by such a cleaning process, adhering particles, such as polishing powder, which could not be completely removed during the cleaning process, may remain on the surface of the dried substrate, resulting in insufficient cleaning. The present disclosure aims to provide a method for cleaning a semiconductor wafer that can further reduce the number of residual particles on the surface of the semiconductor wafer. (Solution to the problem) To solve the aforementioned problem, the inventors of the present disclosure have conducted intensive studies. When a semiconductor wafer is cleaned using a conventional cleaning method, adhering particles remain on the surface of the substrate after drying. As a result, when the surface of the cleaned semiconductor wafer is inspected using a surface inspection device (e.g., Surfscan SP5 or later models manufactured by KLA Corporation), a large number of light spot defects (LPDs), which are presumed to be caused by adhering particles, are detected. Accordingly, the inventors have carried out a detailed investigation of various methods for cleaning semiconductor wafers and have examined the relationship between such methods and the number of LPDs detected on the surface of the cleaned semiconductor wafer. As a result, they found that to efficiently remove adhering particles from the semiconductor wafer, it is effective to temporarily pause the cleaning process during several cleaning treatments using cleaning solutions, perform a drying process on the semiconductor wafer, then add purified water, and then resume the cleaning process. This sequence was found to significantly reduce the number of LPDs caused by adhering particles. The core of the present disclosure, completed based on the foregoing results, is as follows. (1) Method for cleaning a semiconductor wafer, comprising while the semiconductor wafer is being rotated: a first cleaning process to clean the semiconductor wafer; a first drying process to dry the semiconductor wafer after the first cleaning process; a second cleaning process to clean the semiconductor wafer after the first drying process; and a second drying process to dry the semiconductor wafer after the second cleaning process, the first cleaning process comprises the following sequence: an initial ozone cleaning process for supplying an ozone solution to a surface of the semiconductor wafer to perform cleaning; and a first alternating cleaning process that alternately uses: a first hydrofluoric acid cleaning process to clean the surface of the semiconductor wafer with an aqueous solution of hydrofluoric acid; and a first ozone cleaning process to clean the surface with an ozone solution, following the first hydrofluoric acid cleaning process, and the second cleaning process comprises the following sequence: a pure water supply process for supplying pure water to the surface of the semiconductor wafer after the first drying process; a second initial ozone cleaning process for supplying an ozone solution to the surface of the semiconductor wafer to perform cleaning; and a second alternating cleaning process that alternately uses: a second hydrofluoric acid cleaning process to clean the surface of the semiconductor wafer with an aqueous solution of hydrofluoric acid; and a second ozone cleaning process to clean the surface with an ozone solution, following the second hydrofluoric acid cleaning process. (2) Method for cleaning a semiconductor wafer according to (1), wherein the number of additional passes of the alternating cleaning process in the first cleaning process is not less than one and not more than four. (3) Method for cleaning a semiconductor wafer according to (1) or (2), wherein the number of additional passes of the alternating cleaning proc