Seed crystal hot-pressing bonding mechanism and seed crystal bonding method

Abstract

The invention relates to a seed crystal hot-pressing bonding mechanism, which comprises a carrying table, a pressure plate and a cooling ring, and is characterized in that the carrying table comprises a carrying table body and an ejection assembly which is movably arranged on the carrying table body and can jack up a seed crystal seat on the carrying table body and separate the seed crystal seat from the carrying table body; the pressure plate is used for being matched with the carrying table body to press the seed crystal seat between the pressure plate and the carrying table body; the cooling ring is annularly arranged on the outer side of the seed crystal seat and is communicated with a cooling gas source, and gas spraying holes are formed in the inner side of the cooling ring and are used for spraying cooling gas to cool the seed crystal seat. According to the invention, the ejection assembly is arranged on the carrying table body, so that the seed crystal seat on the carrying table body can be ejected and separated from the carrying table body, and the heat dissipation of the seed crystal seat and the carrying table body can be accelerated; meanwhile, through the design of the cooling ring, the cooling speed of the seed crystal seat and the carrying table body is further increased, rapid cooling of the seed crystal seat is achieved, the bonding quality of the seed crystal plate and the seed crystal seat is guaranteed, and meanwhile the production efficiency is higher.

Description

Technical Field

[0001] The invention belongs to the technical field of seed crystal bonding, and in particular relates to a seed crystal hot pressing bonding mechanism and a seed crystal bonding method. Background Art

[0002] Silicon carbide (SiC), as a typical representative of the third generation of semiconductor materials, has the characteristics of wide band gap, high breakdown electric field strength and high thermal conductivity. It is one of the most important third generation semiconductor materials and can meet the high requirements of substrate materials under harsh conditions such as high power, high frequency and high temperature in the fields of aerospace, photovoltaic power generation, rail power grid and new energy trams. At present, the most mature and mainstream way to grow silicon carbide single crystals is the physical vapor transport method (PVT). The main steps of this method are: loading silicon carbide powder at the bottom of a graphite crucible, and bonding silicon carbide seed crystals to the top of the crucible, heating the graphite crucible by electromagnetic induction, so that the powder raw material sublimates at high temperature, and finally growing silicon carbide single crystals at the interface of the silicon carbide seed crystals.

[0003] The bonding effect between the silicon carbide seed crystal and the seed crystal seat directly affects the continuity of crystal growth and the quality of the crystal. Photoresist, epoxy resin, phenolic resin and other polymers are usually used as interface adhesives. The adhesive is applied to the bonding surface of the seed crystal seat and the silicon carbide seed crystal, and then the two are concentrically pressed and bonded, and then hot pressed to improve the curing effect of the adhesive. After the hot pressing is completed, it is taken out after naturally cooling to room temperature. However, the hot pressing temperature of commonly used silicon carbide seed crystals is relatively high (generally 300℃~600℃), and it takes a long time for the seed crystal and the seed crystal seat to cool to room temperature, resulting in long production time and low work efficiency, which will eventually affect the production efficiency of silicon carbide single crystal materials. Summary of the invention

[0004] The object of the present invention is to provide a seed crystal hot-pressing bonding mechanism with high production efficiency.

[0005] Another object of the present invention is to provide a seed crystal bonding method with high production efficiency.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] In one aspect, the present invention provides a seed crystal hot-pressing bonding mechanism, comprising:

[0008] A carrier, the carrier is used to carry a seed crystal seat, the seed crystal seat includes a seed crystal seat body, a seed crystal sheet and an adhesive located therebetween, the carrier includes a carrier body and an ejection assembly movably disposed on the carrier body and capable of lifting the seed crystal seat on the carrier body and separating it from the carrier body;

[0009] A pressure plate, which is used to cooperate with the carrier body to press the seed crystal seat located between the two, and includes a pressure plate body arranged above the carrier body and a driving component for driving the pressure plate body to move in the up and down directions; and

[0010] A cooling ring is arranged on the outside of the seed crystal seat and is connected to a cooling gas source. A gas injection hole is provided on the inside of the cooling ring for injecting cooling gas to cool the seed crystal seat.

[0011] The hot pressing bonding mechanisms in the prior art all achieve cooling of the seed crystal seat by natural cooling after the hot pressing is completed. Since the heat capacity of the carrier body is large, the cooling speed is very slow. The present invention creatively arranges an ejection assembly and a cooling ring on the carrier body to accelerate the cooling speed of the seed crystal seat and the carrier body, which can achieve rapid cooling of the seed crystal seat, ensure the bonding quality of the seed crystal sheet, and at the same time, have higher production efficiency.

[0012] Preferably, the ejection assembly includes a first rod, a second rod and a counterweight, the first rod being rotatably disposed in the carrier body, and including a first part and a second part located on both sides of the rotation axis of the first rod, one end of the second rod being connected to the first part, and the counterweight being disposed on the second part, the sum of the moments from the counterweight and the second part to the rotation axis of the first rod being greater than the sum of the moments from the seed crystal seat, the second rod and the first part to the rotation axis of the first rod, so that when there is no external force, the first part always has a tendency to rotate in a direction close to the seed crystal seat and drive the second rod to move upward to lift the seed crystal seat.

[0013] The present invention can realize automatic ejection of the seed crystal seat through the design of the first rod member, the second rod member and the counterweight member, and has 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 carrier body is provided with a receiving groove and a limiting groove connected to the receiving groove and located above the receiving groove, the first rod is arranged in the receiving groove, and the second rod is arranged in the limiting groove and can be ejected through the limiting groove.

[0016] Furthermore, the accommodating groove is arranged on the outer peripheral side of the carrier body, the second part has an area exposed from the accommodating groove, and the counterweight is arranged on the exposed area of ​​the second part.

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

[0018] Preferably, the ejection assembly has a plurality of groups arranged around the circumference of the carrier body.

[0019] In some embodiments, the counterweight is an annular structure, and multiple groups of ejection assemblies 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-pressing bonding mechanism further comprises a heating device, and the heating device is disposed on the stage body and is used to heat the seed crystal seat.

[0022] Preferably, the gas injection holes include one group or multiple groups arranged in the up-down direction, and each group of gas injection holes includes a plurality of 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 pressing bonding mechanism as described above, comprising the following steps:

[0025] (1) Place the seed crystal seat on the carrier body with the side bonded with the seed crystal facing upward;

[0026] (2) controlling the driving assembly to drive the pressure plate body to move downward and press against the seed crystal seat, so that the ejection assembly is in a non-ejection state, and the seed crystal seat is in contact with the carrier body;

[0027] (3) heating the seed crystal seat so that the seed crystal sheet and the seed crystal seat body are bonded together;

[0028] (4) After the heating is completed, the driving assembly is controlled to drive the pressure plate body to move upward, the ejection assembly lifts up the seed crystal seat and separates it from the carrier body, and cooling gas is introduced into the cooling ring to perform jet cooling on the seed crystal seat.

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

[0030] The present invention provides an ejection assembly on the carrier body, which can lift up the seed crystal seat on the carrier body and separate it from the carrier body, thereby accelerating the heat dissipation of the seed crystal seat and the carrier body; at the same time, through the design of the cooling ring, the cooling speed of the seed crystal seat and the carrier body is further accelerated, ensuring the bonding quality of the seed crystal and the seed crystal seat while increasing production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A schematic structural diagram of a seed crystal hot-pressing bonding mechanism provided in Example 1 of the present invention, wherein the ejection assembly is in a non-ejected state;

[0032] Figure 2 It is another structural schematic diagram of a seed crystal hot-pressing bonding mechanism provided in Example 1 of the present invention, wherein the ejection assembly is in an ejection state;

[0033] Among them, 1. stage body; 11. receiving 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 seat body; 51. Seed crystal chip. DETAILED DESCRIPTION

[0038] In the following, only some exemplary embodiments are briefly described. As those skilled in the art will appreciate, the described embodiments may be modified in various ways without departing from the spirit or scope of the embodiments of the present invention. Therefore, the drawings and descriptions are considered to be exemplary and non-restrictive in nature.

[0039] In the description of the embodiments of the present invention, it should be understood that the terms "upper", "lower", etc. indicate positions or location relationships based on Figure 1 The orientation is defined by the orientation shown, such as the orientation of the platen body 4 is "up", and the orientation of the carrier body 1 is "down". The above-mentioned orientation words are only used to facilitate the description of the embodiments of the present invention and simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the embodiments of the present invention.

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

[0041] In the embodiments of the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0042] The disclosure below provides many different embodiments or examples to implement different structures of the embodiments of the present invention. In order to simplify the disclosure of the embodiments of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the embodiments of the present invention. In addition, the embodiments of the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplification and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed.

[0043] After the silicon carbide seed wafer and the seed crystal seat are bonded by an adhesive, a certain pressure needs to be applied to the bonded seed wafer in a hot press furnace, and at the same time, it needs to be heated and cured by a heating platform, and then taken out after naturally cooling to room temperature. However, the hot pressing temperature is generally between 300°C and 600°C, and it takes a long time for the seed wafer and the seed crystal seat to cool to room temperature, resulting in a long production time for the bonding of the seed wafer and the seed crystal seat, which is not convenient for industrial production. Only by passing cooling gas or coolant into the hot press furnace can the cooling rate of the seed wafer and the seed crystal seat be accelerated to a certain extent, but due to the large heat capacity of the heating platform, the center of the seed wafer and the seed crystal seat will cool down slowly and the edge will cool down quickly, resulting in local stress concentration at the bonding point between the seed wafer and the seed crystal seat, poor bonding quality, and affecting the subsequent crystal growth. The inventor creatively arranges an ejection assembly 2 on the carrier and a cooling ring 3 above the carrier, and lifts up the seed crystal seat bonded with the seed crystal sheet after heating and curing and separates it from the carrier through the ejection assembly 2, and cools it by ejecting cooling gas through the cooling ring 3, so as to avoid the concentration of thermal stress caused by the difference in thermal expansion coefficient between the carrier and the seed crystal seat during the cooling process, and the temperature change of the seed crystal seat and the carrier is more uniform, and the generation of thermal stress can be further reduced. While ensuring the bonding quality of the seed crystal seat, the heating rate of the seed crystal seat is accelerated, and the production efficiency of the seed crystal sheet bonding is improved. The embodiments of the present invention are described in detail below in conjunction with the accompanying drawings.

[0044] If not otherwise specified, the seed crystal seat described herein includes a seed crystal seat body 5, a seed crystal sheet 51, and an adhesive therebetween (not shown in the figures, the adhesive is a conventional adhesive in the art and is not specifically limited).

[0045] Example 1

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

[0047] The carrier includes a carrier body 1 and an ejector assembly 2. The carrier body 1 is used to carry a seed crystal seat, which includes a seed crystal seat body 5, a seed crystal chip 51 and an adhesive located therebetween, and the seed crystal chip 51 includes but is not limited to a silicon carbide seed crystal chip. The ejector assembly 2 is movably disposed on the carrier body 1, and can lift up the seed crystal seat on the carrier body 1 and separate it from the carrier body 1. The ejector assembly 2 has multiple groups evenly distributed along the circumference of the carrier body 1. In this embodiment, the ejector assembly 2 has three groups, and one of the groups is taken as an example for detailed discussion below.

[0048] The ejection assembly 2 includes a first rod 21, a second rod 22 and a counterweight. The first rod 21 is rotatably disposed in the carrier body 1 through a rotating shaft 213, and includes a first portion 211 located on the inner side of the rotation axis centerline of the rotating shaft 213 of the first rod 21 and a second portion 212 located on the outer side of the rotation axis centerline; one end of the second rod 22 is rotatably and slidably connected to the first portion 211; the counterweight is disposed on the second portion 212, and the counterweight can be a counterweight block disposed one-to-one with the second portion 212, or it can be an annular counterweight ring 23 shared by multiple second portions 212. In this embodiment, the counterweight is a counterweight ring 23, which has more uniform force and is easy to replace.

[0049] Further, the sum of the moments of all the counterweights and all the second parts 212 on the carrier body 1 to the rotation axis of the rotating shaft 213 is greater than the sum of the moments of the seed crystal seat and all the second rods 22 on the carrier body 1 and all the first parts 211 to the rotation axis of the rotating shaft 213, so that when there is no external force, the first part 211 always has a tendency to rotate in the direction close to the seed crystal seat and drive the second rod 22 to move upward, thereby lifting the seed crystal seat. Through the design of the first rod 21, the second rod 22 and the counterweight, the automatic ejection of the seed crystal seat can be achieved, the structure is simple, and the operation is convenient. Preferably, 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 rotating shaft 213 is greater than the distance from the second rod 22 to the rotation axis of the rotating shaft 213, so that the seed crystal seat is easier to be ejected.

[0050] In order to cooperate with the installation of the ejection assembly 2, the peripheral side of the carrier body 1 is provided with a receiving groove 11 and a limiting groove 12 extending in the up-down direction and connected to the receiving groove 11 and located above the receiving groove 11. The first rod 21 is rotatably arranged in the receiving groove 11, and the second part 212 thereon has an area exposed to the receiving groove 11, and the counterweight is preferably arranged on the exposed area of ​​the second part 212, so as to facilitate the replacement of counterweights of different models according to the weight of the seed crystal seat, so as to realize the automatic ejection of seed crystal seats of different models and weights. The limiting groove 12 has a plurality of second rods 22 arranged one by one, and the second rod 22 is movably arranged in 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 arranged in the carrier body 1, which is used to heat the carrier body 1 to heat the seed crystal seat thereon. In some other embodiments, the heating device can also be arranged on the platen body 4. The heating device refers to the existing technology, such as an induction coil, etc., and is not specifically limited.

[0051] The cooling ring 3 is arranged on the outside of the seed crystal seat, preferably facing 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, argon, etc.), and has a jet hole on its inner side for ejecting cooling gas to cool the seed crystal seat. The jet holes are provided in one group or multiple groups arranged in the up-down direction, and each group of 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 between the two, and includes a pressure plate body 4 slidably arranged above the stage body 1 in the up-down direction and a driving component 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 any specific restrictions.

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

[0054] (1) Place the seed crystal seat with the seed crystal 51 bonded thereto on the stage body 1, with the side with the seed crystal 51 bonded thereto facing upwards;

[0055] (2) Control the driving assembly to drive the pressure plate body 4 to move downward and press against the seed crystal seat, so that the ejection assembly 2 is in a non-ejection state (such as Figure 1 As shown), the seed crystal seat is fitted with the carrier body 1;

[0056] (3) heating and selectively pressurizing the seed crystal seat to bond the seed crystal sheet 51 to the seed crystal seat body 5;

[0057] (4) After the heating is completed, the control driving assembly drives the pressure plate body 4 to move upward. Under the action of 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 carrier body 1, and then cooling gas is introduced into the cooling ring 3 to perform jet cooling on the seed crystal seat.

[0058] It has been proven that the use of the above-mentioned seed crystal hot pressing bonding mechanism and seed crystal bonding method can ensure the bonding quality, while improving the bonding efficiency by several times or even dozens of times, and is suitable for industrial production.

[0059] The above detailed description of the present invention is intended to enable persons familiar with the art to understand the contents of the present invention and implement them. It does not limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims

1. A seed crystal hot pressing bonding mechanism, characterized in that: include: A carrier, the carrier being used to carry a seed crystal seat, the seed crystal seat comprising a seed crystal seat body (5), a seed crystal sheet (51) and an adhesive located therebetween, the carrier comprising a carrier body (1) and an ejection assembly (2) movably disposed on the carrier body (1) and capable of lifting the seed crystal seat on the carrier body (1) and separating it from the carrier body (1); A pressure plate, the pressure plate is used to cooperate with the carrier body (1) to press the seed crystal seat located between the two, and comprises a pressure plate body (4) arranged above the carrier body (1) and a driving component used to drive the pressure plate body (4) to move in the up and down direction; and A cooling ring (3) is arranged on the outside of the seed crystal seat and is connected to a cooling gas source, and has an injection hole on its inside for ejecting cooling gas to cool the seed crystal seat.

2. The seed crystal hot-pressing bonding mechanism according to claim 1, characterized in that: The ejection assembly (2) comprises a first rod (21), a second rod (22) and a counterweight. The first rod (21) is rotatably arranged in the carrier body (1) and comprises 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 arranged on the second part (212). The total moment of the counterweight and the second part (212) to the rotation axis of the first rod (21) is greater than the total moment of the seed crystal seat, the second rod (22) and the first part (211) to the rotation axis of the first rod (21), so that when no external force is applied, the first part (211) always has a tendency to rotate in a direction close to the seed crystal seat and drive the second rod (22) to move upward to lift the seed crystal seat.

3. The seed crystal hot-pressing bonding mechanism according to claim 2, 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).

4. The seed crystal hot-pressing bonding mechanism according to claim 2, characterized in that: The carrier body (1) is provided with a receiving groove (11) and a limiting groove (12) which is connected with the receiving groove (11) and is located above the receiving groove (11); the first rod (21) is arranged in the receiving groove (11); the second rod (22) is arranged in the limiting groove (12) and can be ejected through the limiting groove (12).

5. The seed crystal hot-pressing bonding mechanism according to claim 4, characterized in that: The accommodating groove (11) is arranged on the outer peripheral side of the carrier body (1), the second part (212) has an area exposed from the accommodating groove (11), and the counterweight is arranged on the exposed area of ​​the second part (212).

6. The seed crystal hot-pressing bonding mechanism according to claim 2, characterized in that: The second rod (22) is rotatably and slidably connected to the first part (211).

7. The seed crystal hot-pressing bonding mechanism according to claim 1, characterized in that: The ejection assembly (2) comprises a plurality of groups arranged around the circumference of the carrier body (1).

8. The seed crystal hot-pressing bonding mechanism according to claim 1, characterized in that: The seed crystal hot-pressing bonding mechanism further comprises a heating device, which is arranged on the carrier body (1) and is used to heat the seed crystal seat.

9. The seed crystal hot-pressing bonding mechanism according to claim 1, characterized in that: The jet holes have one group or multiple groups arranged in the up-down direction, and each group of jet holes includes a plurality of hole bodies (31) evenly arranged along the inner circumference of the cooling ring (3).

10. A seed crystal bonding method, characterized in that: The seed crystal hot pressing bonding mechanism according to any one of claims 1 to 9 comprises the following steps: (1) placing the seed crystal seat on the carrier body (1) with the side bonded with the seed crystal sheet (51) facing upwards; (2) controlling the driving assembly to drive the pressure plate body (4) to move downward and press against the seed crystal seat, so that the ejection assembly (2) is in a non-ejection state, and the seed crystal seat is in contact with the carrier body (1); (3) heating the seed crystal seat so that the seed crystal sheet (51) and the seed crystal seat body (5) are bonded together; (4) After heating is completed, the control driving component drives the pressure plate body (4) to move upward, the ejection component (2) lifts up the seed crystal seat and separates it from the carrier body (1), and cooling gas is introduced into the cooling ring (3) to perform jet cooling on the seed crystal seat.

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