Seed crystal bonding method

Abstract

The invention discloses a seed crystal bonding method, and relates to the technical field of silicon carbide crystal growth. The seed crystal bonding method comprises the following steps: coating a bonding agent on the surface of one side of a seed crystal to form a glue layer; a seed crystal support, a seed crystal and an upper pressing block are sequentially stacked on a heating table, and the glue layer is located between the seed crystal support and the seed crystal; controlling the heating table to start, and raising the heating temperature to a first preset value at a first temperature rise rate; downward preset pressure is applied to the upper pressing block, and the heating temperature of the heating table is controlled to rise to a second preset value from the first preset value at a second temperature rise rate; and controlling the heating table to maintain the heating temperature of the second preset value for a preset duration. According to the seed crystal bonding method provided by the invention, the adhesive can be uniformly dispersed between the seed crystal and the seed crystal support before curing, so that a better bonding effect is obtained.

Description

Technical Field

[0001] This invention relates to the field of silicon carbide crystal growth technology, and more specifically, to a seed crystal bonding method. Background Technology

[0002] In the silicon carbide crystal growth process, an adhesive is typically used to bond the seed crystal to the seed crystal holder. Specifically, the adhesive is first applied to the surface of the seed crystal, then the side of the seed crystal coated with adhesive is placed on the seed crystal holder, and solidification is carried out directly under high temperature and pressure.

[0003] Because most adhesives on the market have high viscosity and poor fluidity, they will directly undergo cross-linking reaction and solidify under high temperature and high pressure. This will result in uneven distribution of the adhesive between the seed crystal and the seed crystal holder, and gaps in the solidified layer, ultimately leading to poor bonding effect of the seed crystal. Summary of the Invention

[0004] The purpose of this invention is to provide a seed crystal bonding method that enables the adhesive to be evenly distributed between the seed crystal and the seed crystal holder before curing, thereby achieving a better bonding effect.

[0005] An embodiment of the present invention provides a technical solution: A seed crystal bonding method, comprising: An adhesive is applied to one side of the seed crystal to form a glue layer; The seed crystal holder, the seed crystal, and the upper pressure block are stacked sequentially on the heating platform, with the adhesive layer positioned between the seed crystal holder and the seed crystal. The heating platform is controlled to start, and the heating temperature is raised to a first preset value at a first temperature rise rate; A downward preset pressure is applied to the upper pressure block, and the heating temperature of the heating table is controlled to increase from the first preset value to the second preset value at a second temperature rise rate; The heating platform is controlled to maintain the heating temperature at the second preset value for a preset duration.

[0006] In an optional embodiment, the first temperature rise rate is 0.5°C / min.

[0007] In an optional implementation, the first preset value is between 65°C and 75°C.

[0008] In an optional implementation, the preset pressure is 400 kgf.

[0009] In an optional embodiment, the second temperature rise rate is 2°C / min.

[0010] In an optional implementation, the second preset value is between 425°C and 435°C.

[0011] In an optional implementation, the preset duration is 60 minutes.

[0012] In an optional embodiment, the weight of the upper pressure block is between 1.5 kg and 2 kg.

[0013] Compared to existing technologies, the seed crystal bonding method provided by this invention involves coating the seed crystal with adhesive and placing it on the surface of the seed crystal holder. The heating stage first heats the adhesive at a gradually increasing temperature. As the temperature rises, the adhesive softens, its viscosity decreases, and it flows under the relatively small gravity of the upper pressure block, freely distributing itself throughout the area between the seed crystal and the seed crystal holder, thus expelling air bubbles between them. Then, a larger preset pressure is applied to the upper pressure block, combined with the heating stage reaching a higher temperature, causing the adhesive to undergo a cross-linking reaction and solidify, forming a tight adhesive layer. Therefore, the beneficial effects of the seed crystal bonding method provided by this invention include: enabling the adhesive to be uniformly distributed between the seed crystal and the seed crystal holder before solidification, resulting in better bonding performance. Attached Figure Description

[0014] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as limiting the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0015] Figure 1 A flowchart illustrating the seed crystal bonding method provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure in which the heating platform, seed crystal holder, seed crystal, and upper pressure block are stacked in sequence.

[0016] Icons: 100-Heating platform; 200-Seed crystal holder; 300-Glue layer; 400-Seed crystal; 500-Upper pressure block. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0019] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0020] In the description of this invention, it should be understood that the terms "upper," "lower," "inner," "outer," "left," "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product of this invention is in use, or the orientation or positional relationship commonly understood by those skilled in the art. They are only used to facilitate the description of this invention and to simplify the description, and are 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. Therefore, they should not be construed as limitations on this invention.

[0021] Furthermore, the terms "first," "second," etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0022] In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, terms such as "set" and "connection" should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0024] Example Please see Figure 1 , Figure 1 The diagram shown is a flowchart of the seed crystal bonding method provided in this embodiment. This seed crystal bonding method is used to bond the seed crystal 400 to the seed crystal holder 200, and may specifically include the following steps: Step S101: Apply adhesive to one side surface of the seed crystal 400 to form an adhesive layer 300.

[0025] Specifically, adhesives can be applied using methods such as dot coating, scraping, screen printing, or spin coating.

[0026] Furthermore, the seed crystal bonding method may also include: In step S102, the seed crystal holder 200, the seed crystal 400 and the upper pressure block 500 are stacked sequentially on the heating table 100, and the adhesive layer 300 is positioned between the seed crystal holder 200 and the seed crystal 400.

[0027] Please refer to the following: Figure 2 , Figure 2 The diagram shows a structure in which the heating platform 100, seed crystal holder 200, seed crystal 400 and upper pressure block 500 are stacked in sequence.

[0028] First, place the seed crystal holder 200 on the heating platform 100, then place the side of the seed crystal 400 with the adhesive layer 300 on the seed crystal holder 200, and then place the upper pressure block 500 on the side of the seed crystal 400 away from the seed crystal holder 200.

[0029] It is understandable that the heating stage 100 can heat the overall structure composed of the seed crystal holder 200, the adhesive layer 300, the seed crystal 400 and the upper pressure block 500. The upper pressure block 500 is used to apply downward pressure to the seed crystal 400, thereby indirectly pressing the adhesive layer 300.

[0030] Please continue reading. Figure 1 Furthermore, the seed crystal bonding method may also include: Step S103: Control the heating stage 100 to start and raise the heating temperature to the first preset value at the first temperature rise rate.

[0031] It is understandable that the heating temperature of the heating stage 100 refers to the temperature at which the heating stage 100 heats the overall structure composed of the seed crystal holder 200, the adhesive layer 300, the seed crystal 400, and the upper pressure block 500. After the heating stage 100 is started, its heating temperature starts from zero and gradually increases at the first temperature rise rate.

[0032] The first temperature rise rate is 0.5℃ / min, and the first preset value is between 65℃ and 75℃, specifically 65℃, 66℃, 67℃, 68℃, 69℃, 70℃, 71℃, 72℃, 73℃, 74℃, or 75℃, etc. Preferably, the first preset value in this embodiment is 70℃.

[0033] After the heating stage 100 is started, its heating temperature starts from zero and rises to 70°C after 140 minutes. During this process, the adhesive gradually softens, its viscosity decreases, and it flows freely under the natural gravity of the upper pressure block 500, thus being evenly distributed in various areas between the seed crystal 400 and the seed crystal holder 200.

[0034] It should be noted that if the weight of the upper pressure block 500 is too small, the pressure applied to the seed crystal 400 will be too small, the flow driving force of the adhesive will be insufficient, and it will be unable to overcome the viscous resistance, resulting in insufficient flow of the adhesive and poor uniformity of distribution.

[0035] If the weight of the upper pressure block 500 is too large, the pressure applied to the seed crystal 400 will be too great, the adhesive will not be able to flow freely, and the flow speed will be too fast, which will trap air and form bubbles, resulting in poor uniformity of distribution.

[0036] Therefore, as a preferred embodiment, the weight of the upper pressure block 500 is between 1.5kg and 2kg, specifically 1.5kg, 1.6kg, 1.7kg, 1.8kg, 1.9kg or 2kg.

[0037] Furthermore, the seed crystal bonding method may also include: Step S104: Apply a downward preset pressure to the upper pressure block 500 and control the heating temperature of the heating stage 100 to rise from a first preset value to a second preset value at a second temperature rise rate.

[0038] After 140 minutes of slow heating, the softened adhesive has been evenly distributed in various areas between the seed crystal 400 and the seed crystal holder 200, and it can now begin to cure.

[0039] In this embodiment, the preset pressure is 400 kgf and the second temperature rise rate is 2 °C / min to achieve rapid heating.

[0040] The second preset value is between 425℃ and 435℃, specifically 425℃, 426℃, 427℃, 428℃, 429℃, 430℃, 431℃, 432℃, 433℃, 434℃, or 435℃, etc. As a preferred embodiment, the second preset value is 430℃.

[0041] Specifically, a downward pressure of 400 kgf is applied to the upper pressure block 500, and the heating temperature of the heating table 100 is controlled to rise from 70°C to 430°C after 180 minutes.

[0042] Furthermore, the seed crystal bonding method may also include: Step S105: Control the heating stage 100 to maintain the heating temperature at the second preset value for a preset duration.

[0043] In this embodiment, the preset time is 60 minutes. After the temperature of the heating stage 100 rises to 430°C, the temperature is stopped and maintained for 60 minutes to ensure that curing is complete.

[0044] In summary, the seed crystal bonding method provided in this embodiment first raises the heating temperature from zero to 70°C at a temperature rise rate of 0.5°C / min before curing, so that the adhesive gradually softens and the viscosity is reduced. Combined with the self-weight of the upper pressure block 500.5kg to 2kg, pressure is applied to the seed crystal 400, so that the softened adhesive flows freely between the seed crystal 400 and the seed crystal holder 200, achieving uniform distribution.

[0045] After the adhesive has softened and spread, a downward pressure of 400 kgf is applied to the upper pressure block 500, and the heating table 100 is raised to a heating temperature of 430°C and maintained for 60 minutes, so that the adhesive undergoes a full cross-linking reaction and solidifies to form a tight adhesive layer.

[0046] Therefore, the seed crystal bonding method provided by the present invention can make the adhesive evenly distributed between the seed crystal 400 and the seed crystal holder 200 before curing, thereby obtaining a better bonding effect.

[0047] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A seed bonding method, characterized by, include: An adhesive is applied to one side of the seed crystal (400) to form an adhesive layer (300). The seed crystal holder (200), the seed crystal (400) and the upper pressure block (500) are stacked sequentially on the heating table (100), and the adhesive layer (300) is placed between the seed crystal holder (200) and the seed crystal (400); The heating stage (100) is started and the heating temperature is raised to a first preset value at a first temperature rise rate; A downward preset pressure is applied to the upper pressure block (500), and the heating temperature of the heating stage (100) is controlled to increase from the first preset value to the second preset value at a second temperature rise rate; The heating stage (100) is controlled to maintain the heating temperature at the second preset value for a preset duration.

2. The seed bonding method according to claim 1, wherein The first temperature rise rate is 0.5℃ / min.

3. The seed bonding method according to claim 1, wherein The first preset value is between 65°C and 75°C.

4. The seed bonding method according to claim 1, wherein The preset pressure is 400 kgf.

5. The seed bonding method according to claim 1, wherein The second temperature rise rate is 2℃ / min.

6. The seed crystal bonding method according to claim 1, characterized in that, The second preset value is between 425°C and 435°C.

7. The seed crystal bonding method according to claim 1, characterized in that, The preset duration is 60 minutes.

8. The seed crystal bonding method according to claim 1, characterized in that, The weight of the upper pressure block (500) is between 1.5 kg and 2 kg.

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