A seed crystal hot-press bonding mechanism and seed crystal bonding method

Abstract

This invention relates to a seed crystal hot-press bonding mechanism, comprising a stage, a pressure plate, and a cooling ring. The stage includes a stage body and an ejection assembly movably disposed on the stage body, capable of lifting and separating the seed crystal substrate on the stage body from the stage body. The pressure plate cooperates with the stage body to press the seed crystal substrate located between the two. The cooling ring is arranged around the outer side of the seed crystal substrate and connected to a cooling gas source, with air jets on its inner side for ejecting cooling gas to cool the seed crystal substrate. This invention, by providing an ejection assembly on the stage body, can lift and separate the seed crystal substrate from the stage body, thereby accelerating the heat dissipation of the seed crystal substrate and the stage body. Simultaneously, the design of the cooling ring further accelerates the cooling rate of the seed crystal substrate and the stage body, achieving rapid cooling of the seed crystal substrate. This ensures the bonding quality between the seed crystal and the seed crystal substrate while increasing production efficiency.

Description

Technical Field

[0001] This invention belongs to the field of seed crystal bonding technology, specifically relating to a seed crystal hot-press bonding mechanism and a seed crystal bonding method. Background Technology

[0002] Silicon carbide (SiC), a typical representative of third-generation semiconductor materials, possesses characteristics such as a wide bandgap, high breakdown electric field strength, and high thermal conductivity. It is one of the most important third-generation semiconductor materials, capable of meeting the stringent requirements of aerospace, photovoltaic power generation, rail power grids, and new energy electric vehicles for substrate materials under harsh conditions such as high power, high frequency, and high temperature. Currently, the most mature and mainstream method for growing silicon carbide single crystals is the physical vapor transport (PVT) method. The main steps of this method are: filling the bottom of a graphite crucible with silicon carbide powder, attaching a silicon carbide seed crystal to the top of the crucible, heating the graphite crucible through electromagnetic induction to cause the powder to sublimate at high temperatures, and finally growing a silicon carbide single crystal at the silicon carbide seed crystal interface.

[0003] The bonding effect between the silicon carbide seed crystal and the seed crystal base directly affects the continuity of crystal growth and crystal quality. Polymers such as photoresist, epoxy resin, and phenolic resin are typically used as interfacial adhesives. This is achieved by coating the adhesive onto the bonding surfaces of the seed crystal base and the silicon carbide seed crystal, then pressing them concentrically together, followed by hot pressing to improve the curing effect of the adhesive. After hot pressing, the crystal is removed after natural cooling to room temperature. However, the hot pressing temperature for commonly used silicon carbide seed crystals is relatively high (generally 300℃~600℃), and the seed crystal and seed crystal base require a long time to cool to room temperature, resulting in long production times, low work efficiency, and ultimately affecting the production efficiency of silicon carbide single crystal materials. Summary of the Invention

[0004] The purpose of this invention is to provide a seed crystal hot-press bonding mechanism with high production efficiency.

[0005] Another objective of this invention is to provide a seed crystal bonding method with high production efficiency.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] This invention provides a seed crystal hot-press bonding mechanism, comprising:

[0008] A stage for carrying a seed crystal slab, the seed crystal slab including a seed crystal slab body, a seed crystal wafer and an adhesive located between the two, the stage including a stage body and an ejection assembly movably disposed on the stage body and capable of lifting the seed crystal slab on the stage body and separating it from the stage body.

[0009] A pressure plate, which cooperates with the stage body to press a seed crystal seat located between the two, includes a pressure plate body disposed above the stage body and a drive assembly for driving the pressure plate body to move in a vertical direction; and...

[0010] A cooling ring is disposed around the outside of the seed crystal seat and connected to a cooling gas source. An air jet hole is provided on its inner side to spray out cooling gas to cool the seed crystal seat.

[0011] Existing hot-press bonding mechanisms cool the seed crystal substrate by natural cooling after hot pressing. Due to the large heat capacity of the stage body, the cooling rate is very slow. This invention creatively accelerates the cooling rate of the seed crystal substrate and stage body by incorporating an ejector assembly and a cooling ring on the stage body. This enables rapid cooling of the seed crystal substrate, ensuring the bonding quality of the seed crystal wafer while increasing production efficiency.

[0012] Preferably, the ejection assembly includes a first rod, a second rod, and a counterweight. The first rod is rotatably disposed within the platform body and includes a first portion and a second portion located on both sides of the rotation axis of the first rod. One end of the second rod is connected to the first portion. The counterweight is disposed on the second portion. The sum of the torques of the counterweight and the second portion to the rotation axis of the first rod is greater than the sum of the torques of the seed crystal seat, the second rod, and the first portion to the rotation axis of the first rod, so that when no external force is applied, the first portion always has a tendency to rotate towards the seed crystal seat and drive the second rod to move upward to lift the seed crystal seat.

[0013] The present invention, through the design of the first rod, the second rod, and the counterweight, enables the automatic ejection of the seed crystal seat, with a simple structure and convenient operation.

[0014] In some embodiments, the length of the second portion is greater than the length of the first portion, and the distance from the counterweight to the rotation axis of the first rod is greater than the distance from the second rod to the rotation axis of the first rod.

[0015] In some embodiments, the platform body has a receiving groove and a limiting groove that communicates with the receiving groove and is located above the receiving groove. The first rod is disposed in the receiving groove, and the second rod is disposed in the limiting groove and can be pushed out through the limiting groove.

[0016] Furthermore, the receiving groove is provided on the outer periphery of the platform body, the second part has an area exposed outside the receiving groove, and the counterweight is provided on the exposed area of ​​the second part.

[0017] In some implementations, the second rod is rotatably and slidably connected to the first portion.

[0018] Preferably, the ejection assembly has multiple sets arranged circumferentially around the platform body.

[0019] In some embodiments, the counterweight is a ring structure, and multiple sets of the ejection components share one counterweight.

[0020] In some embodiments, the ejection assembly has 2 to 4 groups, more preferably 3 groups.

[0021] Preferably, the seed crystal hot-press bonding mechanism further includes a heating device, which is disposed on the carrier body and is used to heat the seed crystal seat.

[0022] Preferably, the jet holes have one set or multiple sets arranged in the vertical direction, and each set of jet holes includes multiple hole bodies evenly arranged along the inner circumference of the cooling ring.

[0023] Preferably, the seed wafer is a silicon carbide seed wafer.

[0024] The present invention also provides a seed crystal bonding method, based on the seed crystal hot-press bonding mechanism described above, comprising the following steps:

[0025] (1) Place the seed crystal holder on the stage body with the side of the seed crystal attached facing up;

[0026] (2) The control drive component drives the pressure plate body to move down and press against the seed crystal seat, so that the ejection component is in the non-ejection state, and the seed crystal seat is in contact with the stage body;

[0027] (3) Heat the seed crystal seat to bond the seed crystal wafer to the seed crystal seat body as a whole;

[0028] (4) After heating is completed, the control drive component drives the pressure plate body to move upward, the ejection component lifts the seed crystal seat and separates it from the stage body, and introduces cooling gas into the cooling ring to perform jet cooling on the seed crystal seat.

[0029] Due to the application of the above-mentioned technical solution, the present invention has the following advantages compared with the prior art:

[0030] This invention, by setting an ejection component on the stage body, can lift the seed crystal seat on the stage body and separate it from the stage body, thereby accelerating the heat dissipation of the seed crystal seat and the stage body; at the same time, through the design of the cooling ring, the cooling speed of the seed crystal seat and the stage body is further accelerated, ensuring the bonding quality of the seed crystal and the seed crystal seat while achieving higher production efficiency. Attached Figure Description

[0031] Figure 1 This is a schematic diagram of a seed crystal hot-press bonding mechanism provided in Embodiment 1 of the present invention, wherein the ejection component is in a non-ejection state;

[0032] Figure 2 This is another structural schematic diagram of a seed crystal hot-press bonding mechanism provided in Embodiment 1 of the present invention, wherein the ejection component is in the ejection state;

[0033] Among them, 1. Platform body; 11. Accommodating groove; 12. Limiting groove;

[0034] 2. Ejector assembly; 21. First rod; 211. First part; 212. Second part; 213. Rotating shaft; 22. Second rod; 23. Counterweight ring;

[0035] 3. Cooling ring; 31. Hole body;

[0036] 4. Pressure plate body;

[0037] 5. Seed crystal base body; 51. Seed crystal wafer. Detailed Implementation

[0038] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the embodiments of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0039] In the description of the embodiments of the present invention, it should be understood that the terms "upper," "lower," etc., indicate the orientation or positional relationship as described above. Figure 1 The orientations are defined as shown, such as the orientation of the pressure plate body 4 being "upper" and the orientation of the platform body 1 being "lower". The above description of orientation terms is only for the convenience of describing the embodiments of the present invention and simplifying the description, and is not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the embodiments of the present invention.

[0040] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0041] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0042] The following disclosure provides many different implementations or examples for carrying out different structures of the embodiments of the present invention. To simplify the disclosure of the embodiments of the present invention, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the embodiments of the present invention. Furthermore, reference numerals and / or reference letters may be repeated in different examples of the embodiments of the present invention; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed.

[0043] After the silicon carbide seed wafer and seed substrate are bonded together with an adhesive, a certain pressure needs to be applied to the bonded seed wafer in a hot press furnace, while it is simultaneously heated and cured using a heated stage. After naturally cooling to room temperature, it is removed. However, the hot pressing temperature is generally between 300℃ and 600℃, and the seed wafer and seed substrate require a long time to cool to room temperature, resulting in a long bonding production time and making it inconvenient for industrial production. Simply introducing cooling gas or coolant into the hot press furnace can accelerate the cooling rate of the seed wafer and seed substrate to some extent, but due to the large heat capacity of the heated stage, the center of the seed wafer and seed substrate cools slowly while the edges cool quickly. This leads to localized stress concentration at the bonding point, resulting in poor bonding quality and affecting subsequent crystal growth. The inventors have creatively incorporated an ejector assembly 2 and a cooling ring 3 above the stage. The ejector assembly 2 lifts the seed wafer-bonded substrate after heat curing and separates it from the stage, while the cooling ring 3 sprays cooling gas to lower the temperature. This avoids thermal stress concentration caused by the difference in thermal expansion coefficients between the stage and the seed wafer during cooling, resulting in more uniform temperature changes between the seed wafer and the stage. Furthermore, it reduces thermal stress generation, ensuring the bonding quality of the seed wafer while accelerating the heating rate of the seed wafer and improving the production efficiency of seed wafer bonding. The embodiments of the invention are described in detail below with reference to the accompanying drawings.

[0044] Unless otherwise specified, the seed crystal holder described herein includes the seed crystal holder body 5, the seed crystal wafer 51, and the adhesive located between the two (not shown in the figure; the adhesive is a conventional adhesive in the art and is not specifically limited).

[0045] Example 1

[0046] A seed crystal hot-press bonding mechanism, such as Figure 1 and Figure 2 As shown, it includes a stage, a pressure plate, and a cooling ring 3.

[0047] The stage includes a stage body 1 and an ejection assembly 2. The stage body 1 is used to support the seed crystal holder, which includes a seed crystal holder body 5, a seed crystal wafer 51, and an adhesive located between the two. The seed crystal wafer 51 includes, but is not limited to, a silicon carbide seed crystal wafer. The ejection assembly 2 is movably disposed on the stage body 1 and can lift the seed crystal holder on the stage body 1 and separate it from the stage body 1. The ejection assembly 2 has multiple sets evenly distributed along the circumference of the stage body 1. In this embodiment, the ejection assembly 2 has 3 sets, and one set will be described in detail below.

[0048] The ejection assembly 2 includes a first rod 21, a second rod 22, and a counterweight. The first rod 21 is rotatably mounted inside the platform body 1 via a pivot 213. It includes a first part 211 located inside the pivot axis of the pivot 213 of the first rod 21 and a second part 212 located outside the pivot axis. One end of the second rod 22 is rotatably and slidably connected to the first part 211. The counterweight is mounted on the second part 212. The counterweight can be a counterweight block that corresponds one-to-one with the second part 212, or it can be a ring-shaped counterweight ring 23 shared by multiple second parts 212. In this embodiment, the counterweight is a counterweight ring 23, which provides more uniform force application and is easy to replace.

[0049] Furthermore, the sum of the torques of all the counterweights on the stage body 1 and the rotation axes of all the second parts 212 to the rotating shaft 213 is greater than the sum of the torques of the seed crystal seat and the rotation axes of all the second rods 22 and the first parts 211 to the rotating shaft 213 on the stage body 1. This ensures that, without external force, the first part 211 always tends to rotate towards the seed crystal seat and drive the second rods 22 upward, thereby lifting the seed crystal seat. Through the design of the first rod 21, the second rod 22, and the counterweights, automatic ejection of the seed crystal seat can be achieved, resulting in a simple structure and convenient operation. Preferably, the length of the second part 212 is greater than the length of the first part 211, and the distance from the counterweights to the rotation axes of the rotating shaft 213 is greater than the distance from the second rods 22 to the rotation axes of the rotating shaft 213, making it easier to eject the seed crystal seat.

[0050] To facilitate the installation of the ejector assembly 2, the platform body 1 has a receiving groove 11 and a limiting groove 12 extending vertically and communicating with the receiving groove 11 and located above the receiving groove 11. A first rod 21 is rotatably disposed within the receiving groove 11, and its second portion 212 has an area exposed outside the receiving groove 11. A counterweight is preferably disposed on the exposed area of ​​the second portion 212, facilitating the replacement of different types of counterweights according to the weight of the seed crystal, thereby achieving automatic ejection of seed crystals of different types and weights. The limiting groove 12 has multiple corresponding second rods 22, and the second rods 22 are movably disposed within the limiting groove 12 and can be ejected through the limiting groove 12. In this embodiment, a heating device (not shown in the figure) is also provided inside the platform body 1 to heat the platform body 1, thereby heating the seed crystal on it. In other embodiments, the heating device may also be disposed on the pressure plate body 4. The heating device is based on existing technology, such as induction coils, and is not specifically limited.

[0051] The cooling ring 3 is disposed around the outer side of the seed crystal seat, preferably directly opposite the seed crystal seat in the ejected state. The cooling ring 3 is connected to a cooling gas source (usually an inert gas, such as nitrogen or argon), and has air jet holes on its inner side for spraying cooling gas to cool the seed crystal seat. The air jet holes are in one set or multiple sets arranged in the vertical direction, and each set of air jet holes includes multiple hole bodies 31 evenly arranged along the inner circumference of the cooling ring 3.

[0052] The pressure plate is used to cooperate with the stage body 1 to press the seed crystal seat located between the two. It includes a pressure plate body 4 disposed above the stage body 1 in a vertical direction and a driving assembly for driving the pressure plate body 4 to slide. The structure of the pressure plate can refer to the prior art, and this application does not make specific limitations.

[0053] The working principle of the above-mentioned seed crystal hot-press bonding mechanism is as follows:

[0054] (1) Place the seed crystal holder with the seed crystal 51 attached onto the stage body 1, with the side with the seed crystal 51 attached facing upwards.

[0055] (2) The control drive component drives the pressure plate body 4 to move down and press against the seed crystal seat, so that the ejection component 2 is in the non-ejection state (e.g., Figure 1 As shown), the seed crystal base is attached to the stage body 1;

[0056] (3) The seed crystal seat is heated and selectively pressurized to bond the seed crystal 51 to the seed crystal seat body 5 as a whole.

[0057] (4) After heating is completed, the control drive assembly drives the pressure plate body 4 to move upward. Under the gravity of the counterweight, the second part 212 of the first rod 21 rotates downward, causing the first part 211 to rotate upward, thereby driving the second rod 22 to move upward. The end of the second rod 22 away from the first part 211 passes through the limiting groove 12 and lifts the seed crystal seat upward, separating it from the stage body 1. Then, cooling gas is introduced into the cooling ring 3 to perform jet cooling on the seed crystal seat.

[0058] Verification has shown that the above-mentioned seed crystal hot-press bonding mechanism and seed crystal bonding method can guarantee bonding quality and improve bonding efficiency by several times or even tens of times, making it suitable for industrial production.

[0059] The present invention has been described in detail above, with the aim of enabling those skilled in the art to understand and implement the invention. However, this description should not be construed as limiting the scope of protection of the invention. All equivalent changes or modifications made in accordance with the spirit and essence of the invention should be included within the scope of protection of the invention.

Claims

1. A seed crystal hot-pressing bonding mechanism, characterized in that, include: A stage for carrying a seed crystal base, the seed crystal base including a seed crystal base body (5), a seed crystal wafer (51) and an adhesive located between the two, the stage including a stage body (1) and an ejection assembly (2) movably disposed on the stage body (1) and capable of lifting the seed crystal base on the stage body (1) and separating it from the stage body (1). A pressure plate, which is used to cooperate with the stage body (1) to press the seed crystal seat located between the two, includes a pressure plate body (4) disposed above the stage body (1) and a drive assembly for driving the pressure plate body (4) to move in the vertical direction; and, A cooling ring (3) is disposed around the outside of the seed crystal seat and connected to a cooling gas source. An air jet hole is provided on its inner side for spraying cooling gas to cool the seed crystal seat. The ejection assembly (2) includes a first rod (21), a second rod (22), and a counterweight. The first rod (21) is rotatably disposed within the platform body (1) and includes a first part (211) and a second part (212) located on both sides of the rotation axis of the first rod (21). One end of the second rod (22) is connected to the first part (211). The counterweight is disposed on the second part (212). The sum of the torques of the counterweight and the second part (212) to the rotation axis of the first rod (21) is greater than the sum of the torques of the seed crystal seat, the second rod (22), and the first part (211) to the rotation axis of the first rod (21). This ensures that, without external force, the first part (211) always tends to rotate toward the seed crystal seat and drive the second rod (22) to move upward to lift the seed crystal seat.

2. The seed crystal hot-press bonding mechanism according to claim 1, characterized in that, The length of the second part (212) is greater than the length of the first part (211), and the distance from the counterweight to the rotation axis of the first rod (21) is greater than the distance from the second rod (22) to the rotation axis of the first rod (21).

3. The seed crystal hot-press bonding mechanism according to claim 1, characterized in that, The platform body (1) has a receiving groove (11) and a limiting groove (12) connected to the receiving groove (11) and located above the receiving groove (11). The first rod (21) is located in the receiving groove (11), and the second rod (22) is located in the limiting groove (12) and can be pushed out through the limiting groove (12).

4. The seed crystal hot-press bonding mechanism according to claim 3, characterized in that, The receiving groove (11) is provided on the outer periphery of the platform body (1), the second part (212) has an area exposed outside the receiving groove (11), and the counterweight is provided on the exposed area of ​​the second part (212).

5. The seed crystal hot-press bonding mechanism according to claim 1, characterized in that, The second rod (22) is rotatably and slidably connected to the first part (211).

6. The seed crystal hot-press bonding mechanism according to claim 1, characterized in that, The ejection assembly (2) has multiple sets arranged circumferentially around the platform body (1).

7. The seed crystal hot-press bonding mechanism according to claim 1, characterized in that, The seed crystal hot pressing bonding mechanism also includes a heating device, which is disposed on the platform body (1) and is used to heat the seed crystal seat.

8. The seed crystal hot-press bonding mechanism according to claim 1, characterized in that, The jet holes have one set or multiple sets arranged in the up-down direction, and each set of jet holes includes multiple hole bodies (31) evenly arranged along the inner circumference of the cooling ring (3).

9. A seed crystal bonding method, characterized in that, The seed crystal hot-press bonding mechanism based on any one of claims 1 to 8 includes the following steps: (1) Place the seed crystal holder on the stage body (1) with the side of the seed crystal (51) attached facing upwards; (2) The control drive component drives the pressure plate body (4) to move down and press against the seed crystal seat, so that the ejection component (2) is in the non-ejection state, and the seed crystal seat is in contact with the stage body (1); (3) Heat the seed crystal seat to bond the seed crystal wafer (51) to the seed crystal seat body (5) as a whole; (4) After heating is completed, the control drive component drives the pressure plate body (4) to move upward, the ejection component (2) lifts the seed crystal seat and separates it from the stage body (1), and introduces cooling gas into the cooling ring (3) to perform jet cooling on the seed crystal seat.

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