A method for front-side processing of silicon carbide wafers

Abstract

This invention relates to the field of silicon carbide wafer processing technology, specifically a method for processing the front side of a silicon carbide wafer. The invention includes the following steps: S11, taking a high-temperature resistant carrier plate with pores, attaching the back side of a silicon carbide wafer that has completed the front-end processing to the high-temperature resistant carrier plate, and then using an air extraction device to extract air from the bottom of the high-temperature resistant carrier plate to adsorb the silicon carbide wafer onto the high-temperature resistant carrier plate; S12, for the silicon carbide wafer obtained in step S11, firstly performing carbon deposition on the front side of the silicon carbide wafer, so that the carbon deposition layer on the outside of the silicon carbide wafer provides protection for the silicon carbide wafer, facilitating the processing of the front side of the silicon carbide wafer. This not only eliminates the need for direct etching of the silicon carbide wafer, but also eliminates the need for permanent bonding between the silicon carbide wafer and the high-temperature resistant carrier plate, making the processing of the front side of the silicon carbide wafer much easier.

Description

Technical Field

[0001] This invention relates to the field of silicon carbide wafer processing technology, specifically a method for processing the front side of a silicon carbide wafer. Background Technology

[0002] Silicon carbide wafers, also known as silicon carbide single crystal wafers, are sheet-like single crystal materials obtained by cutting, grinding, and polishing silicon carbide crystals along a specific crystallization direction.

[0003] When processing the front side of a silicon carbide wafer, in order to facilitate the processing of the silicon carbide wafer, it is necessary to perform a gentle slope treatment on the front side of the silicon carbide wafer by etching, and then permanently bond the back side of the silicon carbide wafer to a silicon substrate, such as the method for processing the front side of a compound semiconductor wafer based on a silicon substrate proposed in patent application number "202110204734.1".

[0004] However, existing silicon carbide wafer front-side processing technology has the following drawbacks:

[0005] I. Silicon carbide wafers, as a semiconductor compound, have high strength, stable properties, and are difficult to etch.

[0006] Second, the permanent bonding process for silicon carbide wafers to silicon substrates is complex and difficult. Summary of the Invention

[0007] The purpose of this invention is to provide a method for processing the front side of a silicon carbide wafer to solve the problems mentioned in the background art.

[0008] The objective of this invention can be achieved through the following technical solutions:

[0009] S11. Take a high-temperature resistant carrier plate with pores, attach a silicon carbide wafer that has completed the front-end process to the back of the high-temperature resistant carrier plate, and then use an air extraction device to extract air from the bottom of the high-temperature resistant carrier plate to adsorb the silicon carbide wafer onto the high-temperature resistant carrier plate.

[0010] S12. For the silicon carbide wafer obtained in step S11, firstly, carbon deposition is performed on the front side of the silicon carbide wafer to form a carbon deposition layer on the front side of the silicon carbide wafer. Then, the gas extraction of the gas extraction equipment is stopped and the gas extraction equipment is removed. Then, photoresist is coated on the carbon deposition layer surface located at the edge and outside of the silicon carbide wafer. Finally, the carbon deposition layer surface is etched to expose the front side of the silicon carbide wafer.

[0011] S13. Perform a front-side process on the silicon carbide wafer from step S12.

[0012] S14. Take a glass carrier plate for the silicon carbide wafer obtained in step S13, coat the glass carrier plate with a transparent release agent, coat the front side of the silicon carbide wafer with a transparent adhesive, bond the glass carrier plate to the front side of the silicon carbide wafer, then flip the silicon carbide wafer, then use stealth laser cutting to break the high temperature resistant carrier plate and carbon deposition layer, then remove the high temperature resistant carrier plate, and finally perform the subsequent back side process of the silicon carbide wafer.

[0013] Preferably, in step S11, the high-temperature resistant carrier plate material used is graphite or ceramic.

[0014] Preferably, in step S12, dry etching is used when etching the surface of the carbon deposition layer, and the carbon deposition layer on the front side of the silicon carbide wafer is etched, while the part coated with photoresist is not etched.

[0015] Preferably, in step S14, when bonding the glass carrier to the front side of the silicon carbide wafer, the side of the glass carrier coated with the release agent is attached to the front side of the silicon carbide wafer coated with the adhesive, forming a bonding layer between the glass carrier and the silicon carbide wafer, thereby flattening the front side of the silicon carbide wafer and completing the bonding of the glass carrier and the silicon carbide wafer.

[0016] Preferably, in step S11, the first half of the silicon carbide wafer process includes laser stealth cutting, grinding, polishing and epitaxial processes on the front side of the silicon carbide wafer; in step S13, the front side process of the silicon carbide wafer includes transistor fabrication, circuit fabrication and metal connector fabrication; in step S14, the subsequent back side process of the silicon carbide wafer includes thinning and particle implantation.

[0017] A method for processing the front side of a silicon carbide wafer further includes the following steps:

[0018] S21. Take a high-temperature resistant carrier plate with pores, attach multiple silicon carbide wafers that have completed the front-end process to the back of the high-temperature resistant carrier plate, and then use an air extraction device to extract air from the bottom of the high-temperature resistant carrier plate to adsorb multiple silicon carbide wafers in a ring array onto the high-temperature resistant carrier plate.

[0019] S22. Carbon deposition is performed on the front side of multiple silicon carbide wafers to form a carbon deposition layer on the front side of multiple silicon carbide wafers. The gas extraction equipment is stopped and removed. Then, photoresist is applied to the carbon deposition layer on the edges and outer parts of multiple silicon carbide wafers. Finally, the carbon deposition layer is etched to expose the front side of multiple silicon carbide wafers.

[0020] S23. Perform front-side processing on multiple silicon carbide wafers;

[0021] S24. Take a glass substrate, coat it with a transparent release agent, coat the front side of multiple silicon carbide wafers with a transparent adhesive, bond the glass substrate to the front side of multiple silicon carbide wafers, then flip the silicon carbide wafers, and finally perform the subsequent back side process of silicon carbide wafers.

[0022] The beneficial effects of this invention are:

[0023] By etching the carbon deposition layer deposited on the silicon carbide wafer and the carbon deposition layer on top of the silicon carbide wafer, photoresist can provide protection for the deposited area on the outside of the silicon carbide wafer, ensuring that the etching position does not deviate. This allows the carbon deposition layer on the outside of the silicon carbide wafer to protect the silicon carbide wafer and expose the top of the silicon carbide wafer, making it easier to process the front side of the silicon carbide wafer. Not only is it not necessary to directly etch the silicon carbide wafer, but the silicon carbide wafer is also adsorbed and supported by a high-temperature resistant carrier with pores, which facilitates high-temperature processes on the front side of the silicon carbide wafer. There is no need to permanently bond the silicon carbide wafer and the high-temperature resistant carrier, making the processing of the front side of the silicon carbide wafer much easier. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is a flowchart illustrating step S11 in Embodiment 1 of the present invention;

[0026] Figure 2 This is a flowchart illustrating step S12 in Embodiment 1 of the present invention;

[0027] Figure 3 This is a flowchart illustrating step S13 in Embodiment 1 of the present invention;

[0028] Figure 4 This is a flowchart illustrating step S14 in Embodiment 1 of the present invention;

[0029] Figure 5 yes Figure 1 Top view of a medium-temperature resistant carrier plate;

[0030] Figure 6 This is a flowchart illustrating step S21 in Embodiment 1 of the present invention;

[0031] Figure 7 This is a flowchart illustrating step S22 in Embodiment 1 of the present invention;

[0032] Figure 8This is a flowchart illustrating step S23 in Embodiment 1 of the present invention;

[0033] Figure 9 This is a flowchart illustrating step S24 in Embodiment 1 of the present invention;

[0034] Figure 10 yes Figure 6 Top view of a medium-temperature resistant carrier plate.

[0035] The attached figures are labeled as follows:

[0036] 1. Silicon carbide wafer, 2. High-temperature resistant substrate, 3. Pores, 4. Vacuuming equipment, 5. Carbon deposition layer, 6. Photoresist, 7. Glass substrate, 8. Bonding layer. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1

[0039] A method for processing the front side of a silicon carbide wafer includes the following steps:

[0040] S11. Take a high-temperature resistant carrier plate with pores, attach a silicon carbide wafer that has completed the front-end process to the back of the high-temperature resistant carrier plate, and then use an air extraction device to extract air from the bottom of the high-temperature resistant carrier plate to adsorb the silicon carbide wafer onto the high-temperature resistant carrier plate.

[0041] S12. For the silicon carbide wafer obtained in step S11, firstly, carbon deposition is performed on the front side of the silicon carbide wafer to form a carbon deposition layer on the front side of the silicon carbide wafer. Then, the gas extraction of the gas extraction equipment is stopped and the gas extraction equipment is removed. Then, photoresist is coated on the carbon deposition layer surface located at the edge and outside of the silicon carbide wafer. Finally, the carbon deposition layer surface is etched to expose the front side of the silicon carbide wafer.

[0042] S13. Perform a front-side process on the silicon carbide wafer from step S12.

[0043] S14. Take a glass carrier plate for the silicon carbide wafer obtained in step S13, coat the glass carrier plate with a transparent release agent, coat the front side of the silicon carbide wafer with a transparent adhesive, bond the glass carrier plate to the front side of the silicon carbide wafer, then flip the silicon carbide wafer, then use stealth laser cutting to break the high temperature resistant carrier plate and carbon deposition layer, then remove the high temperature resistant carrier plate, and finally perform the subsequent back side process of the silicon carbide wafer.

[0044] like Figure 2 By coating photoresist on the carbon deposition layer surface at the edge and outer part of the silicon carbide wafer, after the carbon deposition layer is etched, the unetched carbon deposition layer will cover the outer surface of the silicon carbide wafer and the top edge of the silicon carbide wafer, thus sealing the edge of the silicon carbide wafer and positioning the silicon carbide wafer on the high temperature resistant carrier.

[0045] In step S11, the high-temperature resistant carrier plate material used is graphite or ceramic.

[0046] Graphite has a melting point of 3652℃-3697℃, while ceramics have a melting point above 2000℃, which can provide a good support for silicon carbide wafers during high-temperature processes.

[0047] In step S12, dry etching is used to etch the carbon deposition layer surface, etching the carbon deposition layer on the front side of the silicon carbide wafer, and the part coated with photoresist will not be etched.

[0048] In step S14, when bonding the glass carrier to the front side of the silicon carbide wafer, the side of the glass carrier coated with the release agent is attached to the front side of the silicon carbide wafer coated with the adhesive, forming a bonding layer between the glass carrier and the silicon carbide wafer, thereby flattening the front side of the silicon carbide wafer and completing the bonding between the glass carrier and the silicon carbide wafer.

[0049] The release agent coated on the glass substrate and the adhesive coated between the silicon carbide wafer are both transparent, making the bonding layer formed by the release agent and the adhesive also transparent. The bonding layer formed by the release agent and the adhesive has the following functions:

[0050] 1. Bonding silicon carbide wafers and glass substrates;

[0051] Second, planarize the front side of the silicon carbide wafer after the first half of the process is completed.

[0052] Third, it facilitates the use of lasers to break the carbon deposition layer through the bonding layer in subsequent processes, thereby removing the carbon deposition from the edge sealing of the silicon carbide wafer.

[0053] In step S11, the first half of the silicon carbide wafer process includes laser stealth cutting, grinding, polishing and epitaxial processes on the front side of the silicon carbide wafer; in step S13, the front side process of the silicon carbide wafer includes transistor fabrication, circuit fabrication and metal interconnect fabrication; in step S14, the subsequent back side process of the silicon carbide wafer includes thinning and particle implantation.

[0054] Compared with related technologies, the front-side processing method for silicon carbide wafers provided by this invention has the following beneficial effects:

[0055] By etching the carbon deposition layer deposited on the silicon carbide wafer and the carbon deposition layer on top of the silicon carbide wafer, photoresist can provide protection for the deposited area on the outside of the silicon carbide wafer, ensuring that the etching position does not deviate. This allows the carbon deposition layer on the outside of the silicon carbide wafer to protect the silicon carbide wafer and expose the top of the silicon carbide wafer, making it easier to process the front side of the silicon carbide wafer. Not only is it not necessary to directly etch the silicon carbide wafer, but the silicon carbide wafer is also adsorbed and supported by a high-temperature resistant carrier with pores, which facilitates high-temperature processes on the front side of the silicon carbide wafer. There is no need to permanently bond the silicon carbide wafer and the high-temperature resistant carrier, making the processing of the front side of the silicon carbide wafer much easier.

[0056] Example 2

[0057] A method for processing the front side of a silicon carbide wafer further includes the following steps:

[0058] S21. Take a high-temperature resistant carrier plate with pores, attach multiple silicon carbide wafers that have completed the front-end process to the back of the high-temperature resistant carrier plate, and then use an air extraction device to extract air from the bottom of the high-temperature resistant carrier plate to adsorb multiple silicon carbide wafers in a ring array onto the high-temperature resistant carrier plate.

[0059] S22. Carbon deposition is performed on the front side of multiple silicon carbide wafers to form a carbon deposition layer on the front side of multiple silicon carbide wafers. The gas extraction equipment is stopped and removed. Then, photoresist is applied to the carbon deposition layer on the edges and outer parts of multiple silicon carbide wafers. Finally, the carbon deposition layer is etched to expose the front side of multiple silicon carbide wafers.

[0060] S23. Perform front-side processing on multiple silicon carbide wafers;

[0061] S24. Take a glass substrate, coat it with a transparent release agent, coat the front side of multiple silicon carbide wafers with a transparent adhesive, bond the glass substrate to the front side of multiple silicon carbide wafers, then flip the silicon carbide wafers, and finally perform the subsequent back side process of silicon carbide wafers.

[0062] Compared with related technologies, the front-side processing method for silicon carbide wafers provided by this invention has the following beneficial effects:

[0063] By adsorbing multiple silicon carbide wafers onto a high-temperature resistant carrier plate, the front-side processing of multiple silicon carbide wafers can be completed simultaneously, thus improving processing speed.

[0064] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed invention.

Claims

1. A method for processing the front side of a silicon carbide wafer, characterized in that, Includes the following steps: S11. Take a high-temperature resistant carrier plate with pores, attach a silicon carbide wafer that has completed the front-end process to the back of the high-temperature resistant carrier plate, and then use an air extraction device to extract air from the bottom of the high-temperature resistant carrier plate to adsorb the silicon carbide wafer onto the high-temperature resistant carrier plate. S12. For the silicon carbide wafer obtained in step S11, firstly, carbon deposition is performed on the front side of the silicon carbide wafer to form a carbon deposition layer on the front side of the silicon carbide wafer. Then, the gas extraction of the gas extraction equipment is stopped and the gas extraction equipment is removed. Then, photoresist is coated on the carbon deposition layer surface located at the edge and outside of the silicon carbide wafer. Finally, the carbon deposition layer surface is etched to expose the front side of the silicon carbide wafer. S13. Perform a front-side process on the silicon carbide wafer from step S12. S14. Take a glass carrier plate for the silicon carbide wafer obtained in step S13, coat the glass carrier plate with a transparent release agent, coat the front side of the silicon carbide wafer with a transparent adhesive, bond the glass carrier plate to the front side of the silicon carbide wafer, then flip the silicon carbide wafer, then use stealth laser cutting to break the high temperature resistant carrier plate and carbon deposition layer, then remove the high temperature resistant carrier plate, and finally perform the subsequent back side process of the silicon carbide wafer.

2. The method for processing the front side of a silicon carbide wafer according to claim 1, characterized in that, In step S11, the high-temperature resistant carrier plate material used is graphite or ceramic.

3. The method for processing the front side of a silicon carbide wafer according to claim 1, characterized in that, In step S12, dry etching is used to etch the carbon deposition layer surface, etching the carbon deposition layer on the front side of the silicon carbide wafer, and the part coated with photoresist will not be etched.

4. The method for processing the front side of a silicon carbide wafer according to claim 1, characterized in that, In step S14, when bonding the glass carrier to the front side of the silicon carbide wafer, the side of the glass carrier coated with the release agent is attached to the front side of the silicon carbide wafer coated with the adhesive, forming a bonding layer between the glass carrier and the silicon carbide wafer, thereby flattening the front side of the silicon carbide wafer and completing the bonding between the glass carrier and the silicon carbide wafer.

5. The method for processing the front side of a silicon carbide wafer according to claim 4, characterized in that, In step S11, the first half of the silicon carbide wafer process includes laser stealth cutting, grinding, polishing and epitaxial processes on the front side of the silicon carbide wafer; in step S13, the front side process of the silicon carbide wafer includes transistor fabrication, circuit fabrication and metal interconnect fabrication; in step S14, the subsequent back side process of the silicon carbide wafer includes thinning and particle implantation.

6. A method for processing the front side of a silicon carbide wafer, characterized in that, It also includes the following steps: S21. Take a high-temperature resistant carrier plate with pores, attach multiple silicon carbide wafers that have completed the front-end process to the back of the high-temperature resistant carrier plate, and then use an air extraction device to extract air from the bottom of the high-temperature resistant carrier plate to adsorb multiple silicon carbide wafers in a ring array onto the high-temperature resistant carrier plate. S22. Carbon deposition is performed on the front side of multiple silicon carbide wafers to form a carbon deposition layer on the front side of multiple silicon carbide wafers. The gas extraction equipment is stopped and removed. Then, photoresist is applied to the carbon deposition layer on the edges and outer parts of multiple silicon carbide wafers. Finally, the carbon deposition layer is etched to expose the front side of multiple silicon carbide wafers. S23. Perform front-side processing on multiple silicon carbide wafers; S24. Take a glass substrate, coat it with a transparent release agent, coat the front side of multiple silicon carbide wafers with a transparent adhesive, bond the glass substrate to the front side of multiple silicon carbide wafers, then flip the silicon carbide wafers, and finally perform the subsequent back side process of silicon carbide wafers.

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