Silicon carbide wafer with bevel and slicing method thereof

Abstract

The present application relates to the technical field of silicon carbide wafer, in particular to a silicon carbide wafer with a guide angle and a slicing method thereof, the present application comprises a silicon carbide wafer, a guide angle for assisting the positioning of surface processing of the silicon carbide wafer is arranged on the silicon carbide wafer, through the guide angle arranged on the silicon carbide wafer, the relative positions of different components needed to be made on the silicon carbide wafer can be accurately mastered in the subsequent processing process of the silicon carbide wafer, and the relative positions of different components cannot be accurately made on the silicon carbide wafer due to the circular silicon carbide wafer, only the corresponding silicon carbide wafer of the guide angle part is cut off in processing, the loss is smaller, more transistors can be made on the silicon carbide wafer, and the coating on the edge of the silicon carbide wafer is more uniform.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicon carbide wafers, in particular to a silicon carbide wafer with a guide angle and a slicing method thereof. BACKGROUND

[0002] A silicon carbide wafer, also known as a silicon carbide single crystal wafer, is a sheet-shaped single crystal material obtained by cutting, grinding and polishing a silicon carbide crystal in a specific crystal direction.

[0003] In the prior art, most silicon carbide wafers are circular. In order to facilitate the subsequent positioning and processing of the silicon carbide wafer, a positioning edge is usually provided on the outer side of the silicon carbide wafer, such as the silicon carbide wafer disclosed in patent application No. 202122627593.2.

[0004] Since the positioning edge on the outer side of the silicon carbide wafer is usually a horizontal cut, it will cause excessive loss during cutting. The horizontal cut will excessively reduce the area of the surface of the silicon carbide wafer, which will not only result in the inability to make more transistors on the silicon carbide wafer during subsequent transistor production, but also make it difficult to uniformly and fully coat the edge of the silicon carbide wafer during edge spin coating. SUMMARY

[0005] The present application aims to provide a silicon carbide wafer with a guide angle and a slicing method thereof to solve the problems raised in the background art.

[0006] The object of the present application can be achieved by the following technical solutions:

[0007] A silicon carbide wafer with a guide angle, comprising a silicon carbide wafer, a guide angle is formed on the surface of the silicon carbide wafer to assist in positioning the surface of the silicon carbide wafer during processing.

[0008] A slicing method for a silicon carbide wafer with a guide angle, comprising the following steps:

[0009] S1. Take a silicon carbide ingot that has undergone the first half of the process, and use a laser stealth cutting method to cut the silicon carbide ingot to form cracks in the horizontal and vertical directions on the silicon carbide ingot, so that the silicon carbide ingot forms a silicon carbide thick slice and a silicon carbide thin slice with a guide angle, and finally bond a glass carrier plate above the silicon carbide thin slice;

[0010] S2, heating the silicon carbide thick slice from the bottom of the silicon carbide thick slice, after heating, turning the silicon carbide wafer and the silicon carbide thick slice, turning the glass carrier plate into the carrier film frame, rapid cooling from the bottom of the glass carrier plate, after cooling, turning the silicon carbide wafer and the silicon carbide thick slice again, using the suction cup to adsorb the glass carrier plate from above, moving the glass carrier plate upward, peeling the silicon carbide wafer from the silicon carbide thick slice, and forming a silicon carbide crystal column above the silicon carbide thick slice;

[0011] S3, in step S2, the glass carrier plate is debonded, and the glass carrier plate is removed from the silicon carbide wafer;

[0012] S4, in step S3, the silicon carbide thick slice is used as a new silicon carbide crystal ingot, and the above steps S1-S3 are repeated until the silicon carbide thick slice is only thick enough to separate two silicon carbide wafers, and a plurality of silicon carbide wafers with an angle are separated, and the cross section of all separated silicon carbide wafers is polished;

[0013] S5, in step S4, the silicon carbide thick slice is cut by femtosecond laser, the silicon carbide crystal column above the silicon carbide thick slice is cut off, the cross section of the silicon carbide thick slice is polished, the silicon carbide crystal ingot is cut by laser stealth cutting method, cracks are formed in the horizontal and vertical directions of the silicon carbide crystal ingot, two silicon carbide wafers with an angle are formed on the silicon carbide thick slice, and the glass carrier plate is bonded to the surface of the two silicon carbide wafers;

[0014] S6, in step S5, after heating and rapid cooling, the upper glass carrier plate is adsorbed by the suction cup, the two silicon carbide wafers are separated, the glass carrier plate is debonded, and the silicon carbide wafer is polished to obtain two silicon carbide wafers with an angle.

[0015] Preferably, in the step S1, the front half of the silicon carbide crystal ingot includes a plurality of uniform silicon carbide crystal ingots cut by laser cutting method.

[0016] Preferably, in the step S1 and the step S5, the bonding method of the glass carrier plate is to coat a release layer on the surface of the glass carrier plate, coat an adhesive on the surface of the silicon carbide wafer, and bond the glass carrier plate with the adhesive on the silicon carbide wafer to form a bonding layer between the glass carrier plate and the silicon carbide wafer, and complete the bonding of the glass carrier plate.

[0017] Preferably, in the step S1 and the step S2, the glass carrier plate used has an angle to enable the glass carrier plate to be fully bonded to the silicon carbide thick slice when the silicon carbide thick slice has a silicon carbide crystal column.

[0018] Preferably, after the glass carrier plate is debonded from the silicon carbide flake in the step S4 and the step S6, the silicon carbide flake is cleaned to remove the residual bonding layer.

[0019] Preferably, after the heating and cold cutting of the silicon carbide wafer are completed in the step S2 and the step S6, the silicon carbide flake is broken at the crack of the silicon carbide flake to facilitate the peeling of the silicon carbide flake from the silicon carbide thick piece.

[0020] Preferably, the heating of the silicon carbide wafer adopts the heat medium contact heating, and the cooling of the silicon carbide wafer adopts the cold medium contact cooling.

[0021] Advantages of the present application:

[0022] By the guide angle arranged on the silicon carbide wafer, the relative positions of different components to be made on the silicon carbide wafer can be accurately grasped in the subsequent processing process of the silicon carbide wafer, so that the relative positions of different components to be made on the silicon carbide wafer cannot be accurately grasped due to the circular silicon carbide wafer, the loss is smaller when only the silicon carbide wafer corresponding to the guide angle part is cut off, more transistors can be made on the silicon carbide wafer, and the coating on the edge of the silicon carbide wafer is more uniform. BRIEF DESCRIPTION OF DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, for those skilled in the art, other drawings can also be obtained without creative labor based on these drawings;

[0024] Figure 1 is a schematic diagram of the overall structure of embodiment 1 of the present application;

[0025] Figure 2 is Figure 1 is a top view of the silicon carbide wafer during coating in embodiment 1;

[0026] Figure 3 is a top view of the silicon carbide wafer in the prior art;

[0027] Figure 4 is Figure 3 is a top view of the silicon carbide wafer during coating in embodiment 2;

[0028] Figure 5 is a process flow chart of step S1 in embodiment 2 of the present application;

[0029] Figure 6 is a process flow chart of step S2 in embodiment 2 of the present application;

[0030] Figure 7 is the process flow chart of step S3 in embodiment 2 of the present application;

[0031] Figure 8 is the process flow chart of step S4 in embodiment 2 of the present application;

[0032] Figure 9 is the process flow chart of step S5 in embodiment 2 of the present application;

[0033] Figure 10 is the process flow chart of step S6 in embodiment 2 of the present application;

[0034] Figure 11 is Figure 6 Structural diagram of the middle silicon carbide flake and silicon carbide thick flake part. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0036] Embodiment 1

[0037] A silicon carbide wafer with a guide angle comprises a silicon carbide wafer, and a guide angle is arranged on the silicon carbide wafer to assist positioning of surface processing of the silicon carbide wafer.

[0038] Compared with the related art, the silicon carbide wafer with a guide angle and the slicing method thereof provided by the present application have the following beneficial effects:

[0039] By arranging the guide angle on the silicon carbide wafer, the relative positions of different components to be made on the silicon carbide wafer can be accurately grasped in subsequent processing of the silicon carbide wafer, so that the different components cannot be accurately made on the silicon carbide wafer due to the circular silicon carbide wafer. Only the silicon carbide wafer corresponding to the guide angle part is cut off during processing, and the loss is smaller. More transistors can be made on the silicon carbide wafer, and the coating on the edge of the silicon carbide wafer is more uniform.

[0040] Embodiment 2

[0041] A slicing method of a silicon carbide wafer with a guide angle comprises the following steps:

[0042] S1, take a piece of silicon carbide ingot after the first half of the process, using laser stealth cutting method for cutting silicon carbide ingot, in the horizontal direction and vertical direction on the silicon carbide ingot form crack, so that the silicon carbide ingot formed silicon carbide thick piece and with the guide angle of silicon carbide thin piece, finally in the silicon carbide thin piece above bonding a glass carrier plate;

[0043] S2, to the silicon carbide thick piece obtained in step S1, from the bottom of the silicon carbide thick piece heating, after heating turn over the silicon carbide thin piece and silicon carbide thick piece, the glass carrier plate is turned to the bearing film frame, from the bottom of the glass carrier plate rapid cooling, after cooling, again turn over the silicon carbide thin piece and silicon carbide thick piece, again using suction cup from the glass carrier plate above the glass carrier plate is adsorbed, drive glass carrier disc to move up, the silicon carbide thin piece from the silicon carbide thick piece peeling, in the silicon carbide thick piece above form a silicon carbide crystal column;

[0044] S3, to the silicon carbide thick piece obtained in step S2, the glass carrier plate is unbound, the glass carrier plate is removed from the silicon carbide thin piece;

[0045] S4, to the silicon carbide thick piece obtained in step S3, as a new silicon carbide ingot is used, repeat the above steps S1-S3, until the silicon carbide thick piece remaining only can separate out two silicon carbide thin piece thickness, separate out a plurality of with the guide angle of silicon carbide thin piece, again to all the separated out silicon carbide thin piece section is polished;

[0046] S5, to the silicon carbide thick piece obtained in step S4, using femtosecond laser cutting, cut off the silicon carbide thick piece above the silicon carbide crystal column, again to the silicon carbide thick piece section is polished, using laser stealth cutting method for cutting silicon carbide ingot, in the horizontal direction and vertical direction on the silicon carbide ingot form crack, so that the silicon carbide thick piece above form two with the guide angle of silicon carbide thin piece and silicon carbide crystal column, again in the two silicon carbide thin piece surface bonding glass carrier plate;

[0047] S6, to the two silicon carbide thin piece obtained in step S5, after heating and rapid cooling, finally using suction cup to the glass carrier plate above is adsorbed, to the two silicon carbide thin piece is separated, after the glass carrier plate unbound, the silicon carbide thin piece is polished, get two with the guide angle of silicon carbide thin piece.

[0048] The glass carrier plate bonded with the silicon carbide thin piece and the silicon carbide thick piece has a guide angle corresponding to the guide angle on the silicon carbide wafer. When the glass carrier plate is bonded, the guide angle on the glass carrier plate is arranged above the guide angle on the silicon carbide wafer.

[0049] In the step S1, the first half of the process of the silicon carbide ingot includes cutting the silicon carbide crystal column into multiple uniform silicon carbide ingots using laser cutting method.

[0050] In the step S1 and the step S5, the bonding method of the glass carrier plate is that a release layer is coated on the surface of the glass carrier plate, an adhesive is coated on the surface of the silicon carbide sheet, the glass carrier plate is bonded to the silicon carbide sheet by the adhesive, and a bonding layer is formed between the glass carrier plate and the silicon carbide sheet, so that the bonding of the glass carrier plate is completed.

[0051] In the step S1 and the step S2, the glass carrier plate has a guide angle, so that the glass carrier plate can be fully bonded to the silicon carbide sheet when the silicon carbide sheet has a silicon carbide crystal column.

[0052] The guide angle on the glass carrier plate is consistent with the crystal column on the silicon carbide sheet, and the silicon carbide crystal column is bonded to the inner wall of the guide angle on the glass carrier plate when the glass carrier plate is bonded to the silicon carbide sheet.

[0053] In the step S4 and the step S6, after the glass carrier plate is unbonded from the silicon carbide sheet, the silicon carbide sheet is cleaned to remove the residual bonding layer.

[0054] In the step S2 and the step S6, after the heating and cold cutting of the silicon carbide wafer are completed, the silicon carbide sheet and the silicon carbide sheet are cracked to facilitate the peeling of the silicon carbide sheet from the silicon carbide sheet.

[0055] The invisible laser cutting is that the laser is focused inside the workpiece to form a modified layer, and the modified layer is cracked after heating and cooling to separate the silicon carbide sheet and the silicon carbide sheet.

[0056] In the step S2 and the step S6, the heating of the silicon carbide wafer is performed by using a heat medium to contact heat, and the cooling of the silicon carbide wafer is performed by using a cooling medium to contact cooling.

[0057] The heating and cooling are performed by the heat medium and the cooling medium to contact, instead of directly heating the silicon carbide wafer, so that the silicon carbide wafer is protected.

[0058] Compared with the related art, the silicon carbide wafer with a guide angle and the slicing method thereof provided by the application have the following beneficial effects:

[0059] By using the invisible laser cutting, not only the loss caused by the cutting can be reduced, but also the invisible laser cutting can form cracks in the horizontal direction and the vertical direction of the silicon carbide ingot when the single silicon carbide sheet is cut each time, so that the silicon carbide sheet with a guide angle can be directly separated, and the silicon carbide sheet does not need to be processed separately, the processing steps of the silicon carbide wafer are simplified, and the processing cost is reduced.

[0060] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited to the above-mentioned embodiments, and the above-mentioned embodiments and descriptions in the specification are only to illustrate the principles of the present application. Without departing from the spirit and scope of the present application, various changes and improvements can be made to the present application, and these changes and improvements all fall within the scope of the claimed present application.

Claims

1. A slicing method of a silicon carbide wafer with a guide angle, comprising a silicon carbide wafer, characterized by, The silicon carbide wafer is provided with a guide angle for assisting the positioning of surface processing of the silicon carbide wafer; The method comprises the following steps: S1, taking a piece of silicon carbide ingot after the first half of the process, using laser stealth cutting method to cut the silicon carbide ingot, forming cracks in the horizontal direction and vertical direction on the silicon carbide ingot, so that the silicon carbide ingot forms a silicon carbide thick piece and a silicon carbide thin piece with a guide angle, and finally bonding a glass carrier plate above the silicon carbide thin piece; S2, heating the silicon carbide thick piece obtained in step S1 from the bottom of the silicon carbide thick piece, after heating, turn over the silicon carbide thin piece and the silicon carbide thick piece, turn over the glass carrier plate into the bearing film frame, cool quickly from the bottom of the glass carrier plate, after cooling, turn over the silicon carbide thin piece and the silicon carbide thick piece again, use the suction cup to adsorb the glass carrier plate from above, move the glass carrier plate upwards, separate the silicon carbide thin piece from the silicon carbide thick piece, and form a silicon carbide crystal column above the silicon carbide thick piece; S3, debonding the glass carrier plate from the silicon carbide thin piece obtained in step S2; S4, using the silicon carbide thick piece obtained in step S3 as a new silicon carbide ingot, repeating the above steps S1-S3 until the silicon carbide thick piece is only thick enough to separate two silicon carbide thin pieces, separating multiple silicon carbide thin pieces with guide angles, and polishing the cross sections of all separated silicon carbide thin pieces; S5, using femtosecond laser cutting to cut off the silicon carbide crystal column above the silicon carbide thick piece obtained in step S4, polishing the cross section of the silicon carbide thick piece, using laser stealth cutting method to cut the silicon carbide ingot, forming cracks in the horizontal direction and vertical direction on the silicon carbide ingot, so that two silicon carbide thin pieces with guide angles and a silicon carbide crystal column are formed on the silicon carbide thick piece, and bonding glass carrier plates on the surfaces of the two silicon carbide thin pieces; S6, after heating and rapid cooling of the two silicon carbide thin pieces obtained in step S5, finally using a suction cup to adsorb the upper glass carrier plate, separating the two silicon carbide thin pieces, debonding the glass carrier plate, and polishing the silicon carbide thin pieces to obtain two silicon carbide thin pieces with guide angles; In the step S1, the first half of the process of the silicon carbide ingot includes cutting the silicon carbide crystal column into multiple uniform silicon carbide ingots using laser cutting method; In the step S1 and step S5, the bonding method of the glass carrier plate is to coat a release layer on the surface of the glass carrier plate, coat an adhesive on the surface of the silicon carbide thin piece, and bond the glass carrier plate coated with the adhesive to the silicon carbide thin piece, so as to form a bonding layer between the glass carrier plate and the silicon carbide thin piece, and complete the bonding of the glass carrier plate.

2. The method of slicing a silicon carbide wafer with a chamfered corner as defined in claim 1, wherein, In the step S1 and step S2, the glass carrier plate used has a guide angle, so that when the silicon carbide thick piece has a silicon carbide crystal column, the glass carrier plate can be fully bonded to the silicon carbide thick piece.

3. The method of slicing a silicon carbide wafer with a bevel according to claim 2, wherein, In the step S4 and step S6, after debonding the glass carrier plate from the silicon carbide thin piece, the silicon carbide thin piece is cleaned to remove the residual bonding layer.

4. The method of slicing a silicon carbide wafer with a chamfered corner as defined in claim 3, wherein, In the step S2 and the step S6, after the heating and cold cutting of the silicon carbide wafer is completed, the crack at the silicon carbide thick slice and the silicon carbide thin slice is broken, so as to peel the silicon carbide thin slice from the silicon carbide thick slice.

5. The method of slicing a silicon carbide wafer with a chamfered corner as defined in claim 4, wherein, In the step S2 and the step S6, the heating of the silicon carbide wafer adopts the heat medium contact heating, and the cooling of the silicon carbide wafer adopts the cold medium contact cooling.

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