CN112652567A - Method for recycling silicon carbide wafer substrate - Google Patents
Method for recycling silicon carbide wafer substrate Download PDFInfo
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- CN112652567A CN112652567A CN201910957396.1A CN201910957396A CN112652567A CN 112652567 A CN112652567 A CN 112652567A CN 201910957396 A CN201910957396 A CN 201910957396A CN 112652567 A CN112652567 A CN 112652567A
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- silicon carbide
- substrate
- recycling
- carbide substrate
- separation interface
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/67—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere
- H01L21/683—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping
- H01L21/6835—Apparatus specially adapted for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus specially adapted for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components ; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
- H01L21/6836—Wafer tapes, e.g. grinding or dicing support tapes
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
- H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
- H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
- H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
- H01L2221/68345—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support used as a support during the manufacture of self supporting substrates
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L2221/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof covered by H01L21/00
- H01L2221/67—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere
- H01L2221/683—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping
- H01L2221/68304—Apparatus for handling semiconductor or electric solid state devices during manufacture or treatment thereof; Apparatus for handling wafers during manufacture or treatment of semiconductor or electric solid state devices or components; Apparatus not specifically provided for elsewhere for supporting or gripping using temporarily an auxiliary support
- H01L2221/68381—Details of chemical or physical process used for separating the auxiliary support from a device or wafer
- H01L2221/68386—Separation by peeling
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- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Manufacturing & Machinery (AREA)
- Computer Hardware Design (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Mechanical Treatment Of Semiconductor (AREA)
Abstract
The invention discloses a method for recycling a silicon carbide wafer substrate. The recycling method comprises the following steps: providing an object comprising a silicon carbide substrate; selecting a surface at a preset depth in the silicon carbide substrate as a separation interface, wherein the separation interface divides the silicon carbide substrate into a first part and a second part in the thickness direction; and irradiating the silicon carbide substrate with laser light, and focusing the laser light on the separation interface, so that the silicon carbide at the separation interface is decomposed, and the first part and the second part of the silicon carbide substrate are separated from each other. According to the method provided by the embodiment of the invention, the silicon carbide wafer substrate is cut by adopting a laser irradiation mode, so that the silicon carbide wafer substrate is recycled, and the manufacturing cost of the silicon carbide-based chip can be greatly reduced.
Description
Technical Field
The invention relates to a method for recycling a silicon carbide wafer substrate, and belongs to the technical field of semiconductor processing.
Background
Silicon carbide-based chips are generally designed to be tens of microns to more than one hundred microns according to the requirements of electrical properties, and in the manufacturing process of silicon carbide-based wafer chips, the wafer thickness is generally greater than four hundred microns based on the requirements of manufacturability and manufacturing yield.
FIG. 1 is a schematic view of a SiC wafer prior to thinning, typically four hundred to six hundred microns thick, 11 being the wafer layer and 21 being the SiC wafer substrate prior to thinning; as shown in fig. 2, a silicon carbide wafer substrate larger than four hundred micrometers is thinned to tens of micrometers required by a chip by means of mechanical grinding, 22 is the thinned silicon carbide wafer substrate, and 31 is a mechanical grinding blade; fig. 3 is a schematic diagram of the silicon carbide wafer after back metallization, and 41 is a back metal layer.
Disclosure of Invention
The invention mainly aims to provide a method for recycling a silicon carbide wafer substrate so as to overcome the defects in the prior art.
In order to achieve the purpose, the technical scheme adopted by the invention comprises the following steps:
the embodiment of the invention provides a method for recycling a silicon carbide wafer substrate, which comprises the following steps:
providing an object comprising a silicon carbide substrate;
selecting a surface at a preset depth in the silicon carbide substrate as a separation interface, wherein the separation interface divides the silicon carbide substrate into a first part and a second part in the thickness direction;
and irradiating the silicon carbide substrate with laser light, and focusing the laser light on the separation interface, so that the silicon carbide at the separation interface is decomposed, and the first part and the second part of the silicon carbide substrate are separated from each other.
Further, the method for recycling the silicon carbide wafer substrate comprises the following steps: and moving at least one laser irradiation device along a preset track, so that the laser emitted by the at least one laser irradiation device is sequentially focused at different selected positions on the separation interface, and the silicon carbide at the different selected positions is decomposed, and finally the first part and the second part of the silicon carbide substrate are completely separated.
Further, the laser irradiation device is moved in a stepwise manner.
In some more specific embodiments, the object is a silicon carbide wafer, and the silicon carbide substrate comprises a 4H-SIC substrate, a 6H-SiC substrate, or a semi-insulating SiC substrate.
In some specific embodiments, the object includes a silicon carbide substrate and a functional device bonded to the silicon carbide substrate, where the functional device includes a functional device capable of being bonded to the silicon carbide substrate, and details thereof are not repeated here.
In some more specific embodiments, the object includes a silicon carbide substrate and a semiconductor structure formed on the silicon carbide substrate, and the semiconductor structure includes a structure capable of being bonded to the silicon carbide substrate, which is not described herein again.
In some more specific embodiments, the method for recycling a silicon carbide wafer substrate includes:
providing a silicon carbide-based chip and at least one laser irradiation device, wherein the silicon carbide-based chip comprises a silicon carbide substrate and a semiconductor structure formed on the front surface of the silicon carbide substrate;
irradiating the back surface of the silicon carbide substrate by using the at least one laser irradiation device, and focusing laser emitted by the laser irradiation device on a separation interface at a preset depth in the silicon carbide substrate so as to decompose silicon carbide at the separation interface;
irradiating the whole silicon carbide substrate in a stepping laser irradiation mode, and further separating the silicon carbide substrate into a first part and a second part in the thickness direction, wherein the back surface and the front surface of the silicon carbide substrate are arranged in a back-to-back mode.
Further, the laser is focused laser, and the wavelength of the laser is 800-1500 nm.
Further, the distance between the separation interface and the front surface of the silicon carbide substrate is 20-200 μm, and the distance between the separation interface and the back surface of the silicon carbide substrate is typically 200-600 μm.
Further, the separation interface includes a mixture layer mainly composed of polycrystalline silicon formed by decomposition of silicon carbide and carbon.
In some more specific embodiments, the first portion and the second portion of the silicon carbide substrate surface that are separately formed are each formed with the mixture layer.
Compared with the prior art, the method provided by the embodiment of the invention has the advantages that the silicon carbide wafer substrate is cut by adopting a laser irradiation mode, so that the silicon carbide wafer substrate is recycled, and the manufacturing cost of the silicon carbide-based chip can be greatly reduced.
Drawings
FIG. 1 is a schematic structural diagram of a silicon carbide-based chip wafer before thinning is completed;
FIG. 2 is a schematic diagram of a prior art thinning process for a SiC wafer substrate by mechanical grinding;
FIG. 3 is a schematic diagram of a prior art structure after backside metallization of a SiC wafer;
FIG. 4 is a schematic diagram of a method for recycling a SiC wafer substrate in accordance with an exemplary embodiment of the present invention;
FIG. 5 is a schematic structural diagram of a silicon carbide-based chip cut and separated by the method provided by the embodiment of the invention;
fig. 6 is a schematic structural diagram of a silicon carbide-based chip formed after separation by the method according to the embodiment of the present invention, and the silicon carbide-based chip is subjected to back grinding and back metallization to form a complete silicon carbide-based chip;
fig. 7 is a view of a silicon carbide substrate recovered by a method provided by an embodiment of the present invention.
Detailed Description
In view of the deficiencies in the prior art, the inventors of the present invention have made extensive studies and extensive practices to provide technical solutions of the present invention. The technical solution, its implementation and principles, etc. will be further explained as follows.
The silicon carbide is an important material of a third-generation semiconductor, the semiconductor-grade silicon carbide single crystal needs to be manufactured at 2700 ℃, the requirement on the defect density is very high, and the manufacturing cost of the silicon carbide single crystal substrate is very high.
Please refer to fig. 1, which is a schematic structural diagram of a silicon carbide based chip before a silicon carbide based chip wafer is thinned, wherein the thickness of the silicon carbide based chip is usually four hundred to six hundred micrometers, 11 in the diagram is a silicon carbide based chip layer, and 21 is a silicon carbide substrate before thinning.
Referring to fig. 4-7, a method for recycling a sic wafer substrate according to an embodiment of the present invention includes:
1) providing a silicon carbide-based chip and a laser 61 as shown in fig. 1, the silicon carbide-based chip including a silicon carbide substrate 21 and a silicon carbide-based chip layer 11 formed on the front surface of the silicon carbide substrate 21;
2) selecting one surface at a preset depth in the silicon carbide substrate 21 as a separation interface, irradiating the back surface of the silicon carbide substrate 21 by using a laser 61, and focusing a focused laser beam 71 emitted by the laser at the separation interface so as to decompose the silicon carbide at the selected position of the separation interface into a mixture of polysilicon and carbon;
3) irradiating the entire silicon carbide substrate 21 by stepping laser irradiation to decompose silicon carbide at a plurality of selected positions of the separation interface, thereby forming a separation layer 52(53) at the separation interface in the silicon carbide wafer substrate 21, the separation layer including a mixture layer of polycrystalline silicon and carbon formed by decomposing silicon carbide, the separation layer separating the silicon carbide substrate 21 in the thickness direction thereof into a first silicon carbide substrate 23 and a second silicon carbide substrate 24, wherein the first silicon carbide substrate 23 is provided with a silicon carbide-based chip layer 11, and the separation layer 52 and the separation layer 53 are formed on the separation surfaces of the first silicon carbide substrate 23 and the second silicon carbide substrate 24, respectively;
4) grinding and thinning the first silicon carbide substrate 23, and arranging a metal layer 42 on the first silicon carbide substrate 23 to finish the manufacturing of the silicon carbide-based chip, wherein the silicon carbide-based chip layer 11 and the metal layer 42 are respectively arranged on the front surface and the back surface of the silicon carbide-based chip layer 11 in a back-to-back manner;
5) the surface of the formed second silicon carbide substrate 24 is polished and subjected to a cross-sectional treatment to remove the separation layer 53, thereby completing the recovery of the silicon carbide substrate, and the recovered silicon carbide substrate 26 can be used for the production of silicon carbide-based chips as shown in fig. 7.
Wherein, the wavelength of the focused laser beam 71 emitted by the laser is 800-1500nm, and the irradiation mode can be single irradiation of a plurality of lasers or multiple irradiation of one or a plurality of lasers in a stepping mode; the separation interface is at a distance of 20 to 200 μm from the silicon carbide-based chip layer 11.
Specifically, the separation interface may be a surface parallel to the front surface or the back surface of the silicon carbide substrate 21.
According to the method provided by the embodiment of the invention, the silicon carbide wafer substrate is cut by adopting a laser irradiation mode, so that the silicon carbide wafer substrate is recycled, and the manufacturing cost of the silicon carbide-based chip can be greatly reduced.
It should be understood that the above-mentioned embodiments are merely illustrative of the technical concepts and features of the present invention, which are intended to enable those skilled in the art to understand the contents of the present invention and implement the present invention, and therefore, the protection scope of the present invention is not limited thereby. All equivalent changes and modifications made according to the spirit of the present invention should be covered within the protection scope of the present invention.
Claims (10)
1. A method for recycling a silicon carbide wafer substrate is characterized by comprising the following steps:
providing an object comprising a silicon carbide substrate;
selecting a surface at a preset depth in the silicon carbide substrate as a separation interface, wherein the separation interface divides the silicon carbide substrate into a first part and a second part in the thickness direction;
and irradiating the silicon carbide substrate with laser light, and focusing the laser light on the separation interface, so that the silicon carbide at the separation interface is decomposed, and the first part and the second part of the silicon carbide substrate are separated from each other.
2. The method of recycling a silicon carbide wafer substrate according to claim 1, comprising: and moving at least one laser irradiation device along a preset track, so that the laser emitted by the at least one laser irradiation device is sequentially focused at different selected positions on the separation interface, and the silicon carbide at the different selected positions is decomposed, and finally the first part and the second part of the silicon carbide substrate are completely separated.
3. The method of recycling a silicon carbide wafer substrate according to claim 1, characterized in that: the laser irradiation device moves in a stepwise manner.
4. The method of recycling a silicon carbide wafer substrate according to claim 1, characterized in that: the object is a silicon carbide wafer, and the silicon carbide substrate comprises a 4H-SIC substrate, a 6H-SiC substrate or a semi-insulating SiC substrate.
5. The method of recycling a silicon carbide wafer substrate according to claim 1, characterized in that: the object includes a silicon carbide substrate and a functional device bonded to the silicon carbide substrate.
6. The method of recycling a silicon carbide wafer substrate according to claim 1, characterized in that: the object includes a silicon carbide substrate and a semiconductor structure formed on the silicon carbide substrate.
7. The method of recycling a silicon carbide wafer substrate according to claim 1, comprising:
providing a silicon carbide-based chip and at least one laser irradiation device, wherein the silicon carbide-based chip comprises a silicon carbide substrate and a semiconductor structure formed on the front surface of the silicon carbide substrate;
irradiating the back surface of the silicon carbide substrate by using the at least one laser irradiation device, and focusing laser emitted by the laser irradiation device on a separation interface at a preset depth in the silicon carbide substrate so as to decompose silicon carbide at the separation interface;
irradiating the whole silicon carbide substrate in a stepping laser irradiation mode, and further separating the silicon carbide substrate into a first part and a second part in the thickness direction, wherein the back surface and the front surface of the silicon carbide substrate are arranged in a back-to-back mode.
8. The method of recycling a silicon carbide wafer substrate according to claim 1 or 7, characterized in that: the laser is focused laser, and the wavelength of the laser is 800-1500 nm.
9. The method of recycling a silicon carbide wafer substrate according to claim 7, wherein: the distance between the separation interface and the front surface of the silicon carbide substrate is 20-200 μm.
10. The method of recycling a silicon carbide wafer substrate according to claim 1 or 7, characterized in that: the separation interface includes a mixture layer mainly composed of polycrystalline silicon formed by decomposition of silicon carbide and carbon.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201910957396.1A CN112652567A (en) | 2019-10-10 | 2019-10-10 | Method for recycling silicon carbide wafer substrate |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201910957396.1A CN112652567A (en) | 2019-10-10 | 2019-10-10 | Method for recycling silicon carbide wafer substrate |
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| CN112652567A true CN112652567A (en) | 2021-04-13 |
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| CN201910957396.1A Pending CN112652567A (en) | 2019-10-10 | 2019-10-10 | Method for recycling silicon carbide wafer substrate |
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113690183A (en) * | 2021-07-06 | 2021-11-23 | 华为数字能源技术有限公司 | Wafer thinning method |
| WO2023015611A1 (en) * | 2021-08-10 | 2023-02-16 | 苏州龙驰半导体科技有限公司 | Composite structure of semiconductor wafer, and semiconductor wafer and preparation method therefor and application thereof |
| CN116092931A (en) * | 2023-02-21 | 2023-05-09 | 浙江萃锦半导体有限公司 | Laser thinning silicon carbide wafer back surface process |
-
2019
- 2019-10-10 CN CN201910957396.1A patent/CN112652567A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113690183A (en) * | 2021-07-06 | 2021-11-23 | 华为数字能源技术有限公司 | Wafer thinning method |
| WO2023015611A1 (en) * | 2021-08-10 | 2023-02-16 | 苏州龙驰半导体科技有限公司 | Composite structure of semiconductor wafer, and semiconductor wafer and preparation method therefor and application thereof |
| CN116092931A (en) * | 2023-02-21 | 2023-05-09 | 浙江萃锦半导体有限公司 | Laser thinning silicon carbide wafer back surface process |
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Effective date of registration: 20220414 Address after: 215009 room 131, building 46, No. 52, Torch Road, high tech Zone, Suzhou, Jiangsu Province Applicant after: Suzhou Longchi Semiconductor Technology Co.,Ltd. Address before: Room b0604, 388 Ruoshui Road, Suzhou Industrial Park, 215000 Applicant before: SUZHOU HUATAI ELECTRONIC TECHNOLOGY Co.,Ltd. |