A diamond splicing method applicable to multi-size wafer bonding

Abstract

The present invention belongs to the technical field of semiconductor materials and devices, and relates to a diamond splicing method applicable to multi-size wafer bonding, the method comprising the following steps: S1: selecting a temporary substrate greater than or equal to the size of the wafer to be bonded as a carrier; S2: selecting small-sized diamonds of the same thickness, splicing and arranging them, and then temporarily bonding them with the temporary substrate described in step S1; S3: bonding the temporary substrate of the spliced ​​and arranged diamonds described in S2 to the wafer to be bonded described in S1; S4: debonding the diamond semiconductor wafer described in S3 from the temporary substrate, and finally obtaining a diamond-based semiconductor wafer. The present invention solves the problem that the existing diamond size is small and difficult to match with the semiconductor process. The method can select diamonds of different sizes for splicing according to the semiconductor wafer process, and the spliced ​​diamond substrate is used in the semiconductor industry as a large-area heat sink material in a bonding manner, solving the problem of high cost of large-area single diamonds.

Description

Technical Field

[0001] The invention belongs to the technical field of semiconductor materials and devices, and relates to a diamond splicing method applicable to multi-size wafer bonding. Background Art

[0002] As electronic devices are developing towards smaller size, higher output power and higher frequency, heat dissipation issues are becoming more and more prominent. For example, the theoretical output power of GaN power devices is above 40W / mm, but due to the self-heating effect of the device, the power density of GaN-HEMT devices is only 3 to 5W / mm at this stage. Heat dissipation issues have become a key bottleneck hindering the development and application of electronic devices. Diamond has the highest thermal conductivity in nature, and its thermal conductivity can reach 2000W·m -1 ·K -1 At the same time, diamond has the characteristics of low thermal expansion coefficient, high mechanical strength, corrosion resistance, and radiation resistance. Using diamond as an electronic thermal management material can significantly improve the performance and stability of the device, while reducing the packaging volume and achieving space optimization, which has a far-reaching impact on the further development of existing power devices.

[0003] However, the current diamond size is small and cannot fit into the current mainstream SiC and GaN wafer 4-6 inch production lines, thus limiting its large-scale application in high-voltage and high-power thermal management applications in the semiconductor field. At the same time, the cost of diamond manufacturing increases significantly as the size increases.

[0004] In summary, developing a method to combine small-sized, low-cost diamond materials with large-sized semiconductor wafers has become the key to promoting the widespread application of diamond as a semiconductor heat dissipation material. Summary of the invention

[0005] The purpose of the present invention is to provide a diamond splicing method that can be applied to multi-size wafer bonding, so as to solve the technical problem in the prior art that diamond is difficult to match with existing semiconductor production lines due to its small size and high manufacturing cost.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A diamond splicing method applicable to multi-size wafer bonding includes the following four steps:

[0008] S1: Select a temporary substrate that is larger than or equal to the size of the wafer to be bonded as a carrier;

[0009] S2: Select small-sized diamonds of the same thickness, arrange them together, and temporarily bond them to the temporary substrate described in step S1;

[0010] S3: Bonding the temporary substrate with diamonds arranged in S2 to the wafer to be bonded in S1 to obtain a diamond semiconductor wafer with a temporary substrate;

[0011] S4: Debonding the diamond semiconductor wafer described in S3 from a temporary substrate to finally obtain a diamond-based semiconductor wafer that can be used in semiconductor manufacturing processes.

[0012] As a preferred technical solution, the wafer to be bonded in step S1 is a Si wafer, a SiC wafer or a GaN wafer, with a size ranging from 4 to 12 inches.

[0013] As a preferred technical solution, the temporary substrate in step S1 is a silicon substrate, a glass substrate or a sapphire substrate, with a size ranging from 4 to 13 inches.

[0014] As a preferred technical solution, the side length or diameter of the diamond in step S2 is one or more sizes ranging from 3 to 50 mm, the type is single crystal diamond or polycrystalline diamond, the shape is rectangular, circular, trapezoidal, parallelogram or a combination thereof, and the thermal conductivity is 800-2000 W / m·K.

[0015] As a preferred technical solution, the temporary bonding method in step S2 is liquid temporary bonding and solid temporary bonding.

[0016] As a preferred technical solution, the diamond splicing spacing in step S2 is 1-70 μm.

[0017] As a preferred solution, the bonding method in step S3 is one of silicon melt bonding, room temperature bonding in a vacuum environment, and room temperature bonding in an atmospheric environment.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention discloses a diamond splicing method that can be applied to bonding of multi-sized wafers in semiconductor processes. A spliced ​​diamond wafer is prepared by a temporary bonding method, and then bonded with a semiconductor wafer and the temporary substrate is debonded to obtain a diamond-based semiconductor wafer. The problem that the existing diamond is small in size, difficult to match with semiconductor processes, and cannot be mass-produced is solved. This method can select diamonds of different sizes for splicing according to the semiconductor wafer process. The spliced ​​diamond substrate is used in the semiconductor industry as a large-area heat sink material in a bonding manner, solving the problem of high cost of large-area single-piece diamond. In addition, the diamond splicing spacing can reserve loss space for wafer cutting, reduce wafer dicing costs, and improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0021] Figure 1 This is a schematic diagram of a diamond splicing method for bonding multi-sized wafers according to an embodiment of the present invention;

[0022] Figure 2 A schematic diagram of the structure of a diamond-based semiconductor wafer that can be used in semiconductor manufacturing processes and is prepared according to an embodiment of the present invention.

[0023] Among them, 1-quasi-bonding wafer; 2-diamond; 3-temporary substrate. DETAILED DESCRIPTION

[0024] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0025] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0026] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0027] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0028] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0029] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0030] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0031] Embodiment 1: 1) For a 4-inch Si wafer 1 to be bonded, a 4-inch sapphire temporary substrate 2 is selected as a carrier;

[0032] 2) Select several single crystal diamonds 3 of the same thickness, with a thermal conductivity of 1800 W / m·K and a size of 10×10 mm square;

[0033] 3) A 4-inch sapphire substrate 2 is used to arrange and temporarily bond several single crystal diamonds 3 of the same thickness. The temporary bonding method is a liquid method, and the arrangement joint seam is 50 μm (if the thickness of the single crystal diamond is inconsistent after temporary bonding, a flattening treatment can be performed to ensure that the thickness of the single crystal diamond is consistent.);

[0034] 4) Using the diamond surface of the 4-inch sapphire substrate 2 to bond with the 4-inch Si wafer 1 to be bonded, the bonding method is room temperature bonding in an atmospheric environment;

[0035] 5) The 4-inch sapphire substrate 2 is removed through a debonding process to complete the production of a 4-inch diamond-based silicon wafer that can be used in semiconductor manufacturing processes.

[0036] Embodiment 2: 1) For a 4-inch SiC wafer 1 to be bonded, a 5-inch sapphire temporary substrate 2 is selected as a carrier;

[0037] 2) Select several single crystal diamonds 3 with the same thickness, thermal conductivity of 1800 W / m·K and size of 20×20 mm square;

[0038] 3) Use a 5-inch sapphire substrate 2 and several single crystal diamonds 3 of the same thickness to arrange and temporarily bond them. The temporary bonding method is a liquid method, and the arrangement joint seam is 60μm (if the thickness of the single crystal diamond is inconsistent after temporary bonding, flattening treatment can be performed to ensure the consistency of the thickness of the single crystal diamond.);

[0039] 4) Using the diamond surface of the 5-inch sapphire substrate 2 to bond with the 4-inch SiC wafer 1 to be bonded, the bonding method is room temperature bonding in an atmospheric environment;

[0040] 5) The 5-inch sapphire substrate 2 is removed through a debonding process to complete the production of a 5-inch diamond-based SiC wafer that can be used in semiconductor manufacturing processes.

[0041] Embodiment 3: 1) For the 8-inch Si wafer 1 to be bonded, a 9-inch glass temporary substrate 2 is selected as a carrier;

[0042] 2) Select several polycrystalline diamonds 3 with the same thickness, thermal conductivity of 1200 W / m·K and size of 50×50 mm square;

[0043] 3) A 9-inch glass substrate 2 is used to arrange and temporarily bond several polycrystalline diamonds 3 of the same thickness. The temporary bonding method is a liquid method, and the arrangement joint seam is 60 μm (if the thickness of the single crystal diamond is inconsistent after temporary bonding, a flattening treatment can be performed to ensure that the thickness of the single crystal diamond is consistent.);

[0044] 4) Using the diamond surface of the 9-inch glass substrate 2 to bond with the 8-inch Si wafer 1 to be bonded, the bonding method is silicon melt bonding;

[0045] 5) The 9-inch glass substrate 2 is removed through a debonding process to complete the production of an 8-inch diamond-based Si wafer that can be used in semiconductor manufacturing processes.

[0046] Embodiment 4: 1) For a 3-inch GaN wafer 1 to be bonded, a 3-inch glass temporary substrate 2 is selected as a carrier;

[0047] 2) Select several polycrystalline diamonds 3 with the same thickness, thermal conductivity of 1400 W / m·K and size of 7×7 mm square;

[0048] 3) A 3-inch glass substrate 2 is used to arrange and temporarily bond several polycrystalline diamonds 3 of the same thickness. The temporary bonding method is liquid temporary bonding, and the arrangement joint seam is 20 μm (if the thickness of the single crystal diamond is inconsistent after temporary bonding, a flattening treatment can be performed to ensure the consistency of the thickness of the single crystal diamond.);

[0049] 4) Using the diamond surface of the 3-inch glass substrate 2 to bond with the 3-inch GaN wafer 1 to be bonded, the bonding method is room temperature bonding in a vacuum environment;

[0050] 5) The 3-inch glass substrate 2 is removed through a debonding process to complete the production of a 3-inch diamond-based GaN wafer that can be used in semiconductor manufacturing processes.

[0051] Embodiment 5: 1) For a 6-inch SiC wafer 1 to be bonded, a 7-inch silicon substrate 2 is selected as a carrier;

[0052] 2) Select several single crystal diamonds 3 with the same thickness, thermal conductivity of 1900 W / m·K and size of 30×30 mm square;

[0053] 3) Use a 7-inch silicon substrate 2 and several single crystal diamonds 3 of the same thickness to arrange and temporarily bond them. The temporary bonding method is solid-state temporary bonding, and the arrangement joint seam is 50μm (if the thickness of the single crystal diamond is inconsistent after temporary bonding, it can be flattened to ensure the consistency of the thickness of the single crystal diamond.);

[0054] 4) Using the diamond surface of the 7-inch silicon substrate 2 to bond with the 6-inch SiC wafer 1 to be bonded, the bonding method is room temperature bonding in a vacuum environment;

[0055] 5) The 7-inch silicon substrate 2 is removed through a debonding process to complete the production of a 6-inch diamond-based SiC wafer that can be used in semiconductor manufacturing processes.

[0056] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A diamond splicing method applicable to multi-size wafer bonding, characterized in that: It includes the following four steps: S1: Selecting a temporary substrate with a size greater than or equal to that of a wafer to be bonded as a carrier; the wafer to be bonded is a Si wafer, a SiC wafer or a GaN wafer, with a size range of 4-12 inches; S2: Select small-sized diamonds of the same thickness, splice and arrange them, and then temporarily bond them to the temporary substrate described in step S1; the diamond splicing spacing is 1-70 μm; S3: Bonding the temporary substrate with diamonds arranged in S2 with the wafer to be bonded in S1 to obtain a diamond semiconductor wafer with a temporary substrate; S4: Debonding the diamond semiconductor wafer described in S3 from a temporary substrate to finally obtain a diamond-based semiconductor wafer that can be used in semiconductor manufacturing processes.

2. The method according to claim 1, characterized in that: The temporary substrate in step S1 is a silicon substrate, a glass substrate or a sapphire substrate, and has a size ranging from 4 to 13 inches.

3. The method according to claim 1, characterized in that: The diamond in step S2 has a side length or diameter ranging from 3 to 50 mm, is a single crystal diamond or a polycrystalline diamond, has a shape of rectangle, circle, trapezoid, parallelogram or a combination thereof, and has a thermal conductivity of 800 to 2000 W / m·K.

4. The method according to claim 1, characterized in that: The temporary bonding method in step S2 is liquid temporary bonding and solid temporary bonding.

5. The method according to claim 1, characterized in that: The bonding method in step S3 is one of silicon melt bonding, room temperature bonding in a vacuum environment, and room temperature bonding in an atmospheric environment.

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