CN-115910896-B - Front processing method of silicon carbide wafer

CN115910896BCN 115910896 BCN115910896 BCN 115910896BCN-115910896-B

Abstract

The invention relates to the technical field of silicon carbide wafer processing, in particular to a front processing method of a silicon carbide wafer, which comprises the following steps of S11, taking a Gao Wenzai-resistant plate with air holes, attaching the back of the silicon carbide wafer with a front-end processing to a high-temperature-resistant carrier plate, then sucking air from the bottom of the high-temperature-resistant carrier plate by adopting air suction equipment, and adsorbing the silicon carbide wafer to the high-temperature-resistant carrier plate, S12, firstly carrying out carbon deposition on the front of the silicon carbide wafer, so that the outside of the silicon carbide wafer with a carbon deposition layer provides protection for the silicon carbide wafer, thereby facilitating the processing of the front of the silicon carbide wafer, not only directly etching the silicon carbide wafer, but also carrying out adsorption bearing on the silicon carbide wafer by the Gao Wenzai-resistant plate with the air holes, and not carrying out permanent bonding on the silicon carbide wafer and the Gao Wenzai-resistant plate, and reducing the difficulty of the processing technology of the front of the silicon carbide wafer.

Inventors

YAN LIWEI
LIU WENJIE
MA QING
LIN CHUNHUI

Assignees

中晟鲲鹏光电半导体有限公司
浙江同芯祺科技有限公司

Dates

Publication Date: 20260505
Application Date: 20220812

Claims (6)

1. A method for processing the front surface of a silicon carbide wafer, comprising the steps of: S11, taking a Gao Wenzai-resistant plate with air holes, attaching the back surface of a silicon carbide wafer with the front-end process to a high-temperature-resistant carrier plate, and then adopting air extraction equipment to extract air from the bottom of the high-temperature-resistant carrier plate to adsorb the silicon carbide wafer to the high-temperature-resistant carrier plate; S12, carrying out carbon deposition on the front surface of the silicon carbide wafer, forming a carbon deposition layer on the front surface of the silicon carbide wafer, stopping air extraction of air extraction equipment, removing the air extraction equipment, then coating photoresist on the part, located at the edge and outside of the silicon carbide wafer, of the surface of the carbon deposition layer, and finally etching from the surface of the carbon deposition layer to expose the front surface of the silicon carbide wafer; S13, carrying out a front process on the silicon carbide wafer in the step S12; S14, taking a glass carrier plate for the silicon carbide wafer obtained in the step S13, coating a transparent release agent on the glass carrier plate, coating a transparent adhesive on the front surface of the silicon carbide wafer, bonding the glass carrier plate on the front surface of the silicon carbide wafer, overturning the silicon carbide wafer, cutting between the Gao Wenzai resistant plate and the carbon deposition layer by using invisible laser, removing the Gao Wenzai resistant plate, and finally carrying out subsequent back surface processing of the silicon carbide wafer.
2. The method according to claim 1, wherein in the step S11, the Gao Wenzai-resistant plate is graphite or ceramic.
3. The method according to claim 1, wherein in the step S12, dry etching is used to etch the surface of the carbon deposition layer, the carbon deposition layer on the front surface of the silicon carbide wafer is etched, and the photoresist-coated portion is not etched.
4. The method according to claim 1, wherein in the step S14, when the glass carrier is bonded to the front surface of the silicon carbide wafer, a surface of the glass carrier coated with the release agent is bonded to the front surface of the silicon carbide wafer coated with the adhesive, and a bonding layer is formed between the glass carrier and the silicon carbide wafer, so that the front surface of the silicon carbide wafer is planarized, and the bonding of the glass carrier and the silicon carbide wafer is completed.
5. The method of claim 4, wherein in the step S11, the front-side process of the silicon carbide wafer includes laser stealth dicing, grinding, polishing, and epitaxy processes of the front side of the silicon carbide wafer, wherein in the step S13, the front-side process of the silicon carbide wafer includes transistor fabrication, circuit fabrication, and metal interconnect fabrication, and wherein in the step S14, the subsequent back-side process of the silicon carbide wafer includes thinning and particle implantation.
6. The front processing method of the silicon carbide wafer is characterized by further comprising the following steps: S21, taking a Gao Wenzai-resistant plate with air holes, attaching the back surfaces of a plurality of silicon carbide wafers subjected to front-end process to a high-temperature-resistant carrier plate, and exhausting air from the bottom of the high-temperature-resistant carrier plate by adopting air exhaust equipment to adsorb the plurality of silicon carbide wafers to the high-temperature-resistant carrier plate in an annular array; s22, carbon deposition is carried out on the front surfaces of the silicon carbide wafers, carbon deposition layers are formed on the front surfaces of the silicon carbide wafers, air suction of air suction equipment is stopped, the air suction equipment is removed, then photoresist is coated on the portions, located at the edges and outside of the silicon carbide wafers, of the surfaces of the carbon deposition layers, and finally etching is carried out from the surfaces of the carbon deposition layers to expose the front surfaces of the silicon carbide wafers; S23, performing a front-side process on a plurality of silicon carbide wafers; s24, taking a glass carrier plate, coating a transparent releasing agent on the glass carrier plate, coating transparent adhesive on the front surfaces of the silicon carbide wafers, bonding the glass carrier plate to the front surfaces of the silicon carbide wafers, turning over the silicon carbide wafers, and finally carrying out subsequent back surface processing of the silicon carbide wafers.

Description

Front processing method of silicon carbide wafer Technical Field The invention relates to the technical field of silicon carbide wafer processing, in particular to a front processing method of a silicon carbide wafer. Background Silicon carbide wafers, also known as silicon carbide single crystal wafers, are single crystal materials in the form of pieces obtained by cutting, grinding, and polishing silicon carbide crystals in a particular crystallographic direction. In order to facilitate the processing of the front surface of the silicon carbide wafer, the front surface of the silicon carbide wafer needs to be subjected to gentle slope treatment by etching, and then the back surface of the silicon carbide wafer is permanently bonded to a silicon-carrying substrate, as a method for processing the front surface of a compound semiconductor wafer based on the silicon-carrying substrate is proposed in patent application No. 202110204734.1. However, the existing front side processing technology of the silicon carbide wafer has the following defects: 1. the silicon carbide wafer is used as a semiconductor compound, and has high strength, stable property and high etching difficulty; 2. When the silicon carbide wafer is permanently bonded to the silicon-carrying substrate, the process of permanent bonding is complex and difficult. Disclosure of Invention The present invention is directed to a front side processing method of a silicon carbide wafer, so as to solve the problems set forth in the background art. The aim of the invention can be achieved by the following technical scheme: S11, taking a Gao Wenzai-resistant plate with air holes, attaching the back of a silicon carbide wafer with the front-end process to a high-temperature-resistant carrier plate, and then adopting air extraction equipment to extract air from the bottom of the high-temperature-resistant carrier plate to adsorb the silicon carbide wafer to the high-temperature-resistant carrier plate; s12, carrying out carbon deposition on the front surface of the silicon carbide wafer, forming a carbon deposition layer on the front surface of the silicon carbide wafer, stopping air extraction of air extraction equipment, removing the air extraction equipment, then coating photoresist on the part, located at the edge and outside of the silicon carbide wafer, of the surface of the carbon deposition layer, and finally etching from the surface of the carbon deposition layer to expose the front surface of the silicon carbide wafer; S13, carrying out a front process on the silicon carbide wafer in the step S12; S14, taking a glass carrier plate for the silicon carbide wafer obtained in the step S13, coating a transparent release agent on the glass carrier plate, coating a transparent adhesive on the front surface of the silicon carbide wafer, bonding the glass carrier plate on the front surface of the silicon carbide wafer, overturning the silicon carbide wafer, cutting between the Gao Wenzai resistant plate and the carbon deposition layer by using invisible laser, removing the Gao Wenzai resistant plate, and finally carrying out the subsequent back surface processing of the silicon carbide wafer. Preferably, in the step S11, the Gao Wenzai-resistant plate is made of graphite or ceramic. Preferably, in the step S12, dry etching is used to etch the surface of the carbon deposition layer, so that the carbon deposition layer on the front surface of the silicon carbide wafer is etched, and the portion coated with the photoresist is not etched. Preferably, in the step S14, when the glass carrier is bonded to the front surface of the silicon carbide wafer, one surface of the glass carrier coated with the release agent is bonded to the front surface of the silicon carbide wafer coated with the adhesive, and a bonding layer is formed between the glass carrier and the silicon carbide wafer to planarize the front surface of the silicon carbide wafer, thereby completing the bonding of the glass carrier and the silicon carbide wafer. Preferably, in the step S11, the front half process of the silicon carbide wafer comprises laser invisible cutting, grinding, polishing and epitaxy processes of the front surface of the silicon carbide wafer, in the step S13, the front surface process of the silicon carbide wafer comprises transistor manufacture, circuit manufacture and metal connecting piece manufacture, and in the step S14, the subsequent back surface process of the silicon carbide wafer comprises thinning and particle implantation. The front processing method of the silicon carbide wafer further comprises the following steps: S21, taking a Gao Wenzai-resistant plate with air holes, attaching the back surfaces of a plurality of silicon carbide wafers subjected to front-end process to a high-temperature-resistant carrier plate, and exhausting air from the bottom of the high-temperature-resistant carrier plate by adopting air exhaust equipment to adsorb the plurality of silicon