Wafer sheet assembly with high mechanical strength

Abstract

The utility model belongs to the technical field of semiconductors, and discloses a wafer sheet assembly with high mechanical strength, which comprises a sheet wafer, a compression ring and a support disc, and the sheet wafer is clamped between the compression ring and the support disc. The sheet wafer is circular; the outer diameter of the circular ring is larger than the diameter of the slice wafer, and the inner diameter of the circular ring is smaller than the diameter of the slice wafer. The supporting disc is a disc, the outer diameter of the supporting disc is larger than the diameter of the slice wafer, the middle of the supporting disc is sunken, and the edge of the supporting disc is provided with a boss making contact with the slice wafer. The wafer supporting ring is simple in structure and easy to realize, and the mechanical strength of the wafer can be effectively improved by additionally arranging the supporting ring on the periphery of the wafer, so that the smooth proceeding of the wafer process is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of semiconductors, and in particular to a wafer sheet component with high mechanical strength. Background Art

[0002] Power electronic devices, also known as power devices, are mainly used in power conversion applications that handle high voltage and high current, and have high requirements for the energy conversion efficiency of the devices. For power devices, the thinner the device, the lower the on-resistance and the lower the power consumption. As a third-generation semiconductor material, silicon carbide (SiC) material has the characteristics of wide bandgap, high electron mobility, high saturation breakdown electric field strength, and high thermal conductivity, making it an ideal material for preparing power electronic devices.

[0003] In the current silicon carbide device preparation process, it is usually necessary to thin the silicon carbide wafer from 350μm to 150μm, or even to 100μm. However, the mechanical strength of the silicon carbide wafer drops sharply after thinning, and it is easy to break in subsequent processes (such as ohmic metal and welding metal deposition, laser annealing, and wafer-level testing), causing unnecessary losses. At the same time, due to the large warping of the thin film, the automatic conveyor cannot accurately grasp the wafer in the process after thinning, and manual operation is required, resulting in excessive labor costs and low efficiency. The impact of these two problems is becoming larger and more obvious as the wafer size increases.

[0004] The above two problems have also appeared in the process of silicon material devices, but they are well solved by the Taiko process. The Taiko process is a local thinning method invented by Disco. It only thins the inner area of ​​the wafer surface, leaving a width of about 3mm at the edge without thinning, forming a support ring, thereby ensuring that the mechanical strength of the entire wafer is sufficient to support subsequent process steps, while also controlling the warpage within a very small range. However, this method is only suitable for materials with low hardness, and the Mohs hardness of silicon carbide material is as high as 9.5, which consumes a large amount of grinding wheels and is also very brittle. It is impossible to use local thinning to leave the periphery, and the entire surface can only be thinned.

[0005] In view of the problem that the mechanical strength of thin wafers on the market is generally low, the prior art has proposed many improvements, such as the patent with publication number CN111415898A, which provides a wafer assembly and a method for manufacturing the same, wherein the wafer assembly includes: a wafer; a support ring, which is attached to the back edge area of ​​the wafer. This patent attaches a support ring to the back of the wafer so that the thickness of the wafer assembly corresponding to the edge area of ​​the wafer is greater than the thickness corresponding to the center area of ​​the wafer, thereby enabling detection of test points on the front and back of the wafer. However, in this patent, there is no structural coating relationship between the support ring and the wafer, and an adhesive must be used for fixing. This method has the problem of difficult dissociation. At the same time, the semiconductor process has high requirements for the cleanliness and purity of the material, and the adhesive, a multi-component compound (mixture), will cause impurity contamination and has certain limitations. Therefore, there is an urgent need in the art to improve the assembly of thin wafers to overcome the problem of the generally low mechanical strength of existing thin wafers. Summary of the invention

[0006] The utility model aims to propose a method for strengthening the mechanical strength of a thin silicon carbide wafer. The method has a simple structure and is easy to implement. By adding a support ring around the thin wafer, the mechanical strength of the wafer can be effectively improved to ensure the smooth progress of the thin wafer process.

[0007] The technical solution adopted to achieve the purpose of this utility model is:

[0008] A wafer thin film assembly with high mechanical strength comprises a thin film wafer, a pressure ring and a support plate, wherein the thin film wafer is sandwiched between the pressure ring and the support plate; the thin film wafer is circular in shape; the pressure ring is a circular ring, the outer diameter of the circular ring is larger than the diameter of the thin film wafer and the inner diameter is smaller than the diameter of the thin film wafer; the support plate is a circular plate, the outer diameter of the support plate is larger than the diameter of the thin film wafer, the middle of the support plate is concave, and the edge has a boss in contact with the thin film wafer.

[0009] Furthermore, the pressure ring is fixedly connected to the edge of the support plate.

[0010] Furthermore, the pressure ring and the support plate are fixed to each other by means of screws, bayonet or magnetic attraction, so that the pressure ring, the support plate and the thin wafer form a whole.

[0011] Furthermore, the boss on the support plate that contacts the thin wafer is a double-table structure, and a table close to the middle recess contacts the thin wafer.

[0012] The beneficial effect of the utility model is that the utility model can effectively improve the mechanical strength of the wafer by adding a pressure ring around the thin wafer and a support plate at the bottom, thereby ensuring the smooth progress of the thin wafer process. In addition, the utility model strengthens the mechanical strength through a simple mechanical structure, does not require adhesives, does not have impurity pollution, and has the characteristics of high mechanical strength and easy removal, and has a wide range of applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0014] Figure 1 It is a schematic diagram of the position relationship of parts in the component structure of the utility model.

[0015] Figure 2 It is a schematic diagram of a cross-sectional structure in an embodiment of the utility model.

[0016] Figure 3 It is a schematic diagram of a cross-sectional structure in another embodiment of the utility model.

[0017] In the figure: 1. Thin wafer; 2. Pressure ring; 3. Support plate; 4. Screw; 5. Boss. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0019] like Figures 1 to 3 As shown, a wafer thin plate assembly with high mechanical strength includes a thin plate wafer 1, a pressure ring 2 and a support plate 3, and the thin plate wafer 1 is sandwiched between the pressure ring 2 and the support plate 3. In the utility model, the materials of the pressure ring 2 and the support plate 3 are metal, semiconductor, plastic or ceramic, etc., which can play a supporting role and will not affect the wafer.

[0020] like Figures 1 to 3 As shown, the shape of the thin wafer 1 is circular; the shape of the pressure ring 2 is a circular ring, the outer diameter of the circular ring is larger than the diameter of the thin wafer 1 and the inner diameter is smaller than the diameter of the thin wafer 1; the support plate 3 is a circular plate, the outer diameter of the support plate 3 is larger than the diameter of the thin wafer 1, and the middle of the support plate 3 is concave, and the edge has a boss 5 that contacts the thin wafer 1. The above structure can make the pressure ring 2 and the support plate 3 only contact the edge of the thin wafer 1 to prevent it from affecting other structures on the wafer. The concave middle position of the support plate 3 can make the middle position of the side of the thin wafer 1 that contacts the support plate 3 suspended in the air, avoiding the middle of the support plate 3 from contacting the thin wafer 1 and causing scratches on the thin wafer 1.

[0021] In one embodiment of the present invention, the boss 5 is a single-table structure, specifically as follows Figure 2 In another embodiment of the present invention, the boss 5 on the support plate 3 that contacts the thin wafer 1 is a double-table structure, and one of the tables near the middle depression contacts the thin wafer 1. Figure 3 The double-table structure can form a wafer-carrying step on a table near the middle depression. When the thin wafer 1 is placed on the wafer-carrying step, another step can be provided around the thin wafer 1 to prevent the thin wafer 1 from sliding in the tray, thereby ensuring the stability of the structure.

[0022] like Figures 2 to 3 As shown, the pressure ring 2 and the support plate 3 are fixed to each other by screws 4, bayonet or magnetic attraction, so that the pressure ring 2, the support plate 3 and the thin wafer 1 form a whole. In the utility model, the position where the pressure ring 2 and the support plate 3 are in contact and fixed connection is located at the periphery of the thin wafer 1 and does not contact the thin wafer 1.

[0023] The method of the utility model is simple and easy to implement. By adding a pressure ring 2 around the thin wafer 1 and a support plate 3 at the bottom, the mechanical strength of the wafer can be effectively improved to ensure the smooth progress of the thin wafer 1 process. In addition, the utility model strengthens the mechanical strength through a simple mechanical structure, does not require adhesives, does not have impurity pollution, and has the characteristics of high mechanical strength and easy removal, and has a wide range of applications.

[0024] The specific implementation methods described above further illustrate the purpose, technical solutions and beneficial effects of the utility model in detail. It should be understood that the above description is only a specific implementation method of the utility model and is not intended to limit the utility model. Any modifications, equivalent substitutions and improvements made within the scope of the utility model should be included in the protection scope of the utility model.

Claims

1. A wafer thin film assembly with high mechanical strength, It is characterized in that The invention comprises a thin wafer (1), a pressure ring (2) and a support plate (3), wherein the thin wafer (1) is sandwiched between the pressure ring (2) and the support plate (3); the thin wafer (1) is circular in shape; the pressure ring (2) is an annular shape, the outer diameter of the annular shape is greater than the diameter of the thin wafer (1) and the inner diameter is less than the diameter of the thin wafer (1); the support plate (3) is a disc, the outer diameter of the support plate (3) is greater than the diameter of the thin wafer (1), the middle of the support plate (3) is concave, and the edge is provided with a boss (5) in contact with the thin wafer (1).

2. The wafer thin film assembly with high mechanical strength according to claim 1, It is characterized in that The pressure ring (2) and the edge of the support plate (3) are fixedly connected.

3. The wafer thin film assembly with high mechanical strength according to claim 1 or 2, It is characterized in that The pressure ring (2) and the support plate (3) are fixed to each other by means of screws (4), bayonet or magnetic attraction, so that the pressure ring (2), the support plate (3) and the thin wafer (1) form a whole.

4. The wafer thin film assembly with high mechanical strength according to claim 1 or 2, It is characterized in that The boss (5) on the support plate (3) that contacts the thin wafer (1) is a double-table structure, and a table near the middle recess contacts the thin wafer (1).

5. The wafer thin film assembly with high mechanical strength according to claim 3, It is characterized in that The boss (5) on the support plate (3) that contacts the thin wafer (1) is a double-table structure, and a table near the middle recess contacts the thin wafer (1).

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