Vacuum hot-pressing furnace with exhaust structure for seed crystal hot-press bonding

Abstract

This invention relates to the field of hot press furnace technology, and provides a vacuum hot press furnace with an exhaust structure for hot pressing bonding of seed crystals. The furnace includes: a cabinet with support rods fixedly connected to both sides of its top end; a crossbeam fitted at the top of each support rod; a pressure block at the bottom center of each crossbeam; a base fixedly connected to the top center of the cabinet; and a hot press furnace mounted on the top of the base. Symmetrically arranged upper and lower pressure rods are also present. A hydraulic cylinder is installed inside the cabinet, with its drive end connected to the bottom end of the lower pressure rod. An upper pressure plate is fixedly connected to the bottom end of the upper pressure rod. This invention employs a dual-path synchronous exhaust structure with main and auxiliary exhaust, combined with an exhaust channel on the upper pressure plate and a radial trapezoidal exhaust groove design on the lower pressure plate. This allows for rapid removal of residual gas from the furnace cavity and the gap between the seed crystal and the crystal support bonding surface, stabilizing the vacuum level inside the furnace to ≤1×10⁻²Pa, thus preventing defects such as oxidation, porosity, and inclusions during the hot pressing process.

Description

Technical Field

[0001] This invention relates to the field of hot press furnace technology, specifically to a vacuum hot press furnace with an exhaust structure for hot pressing and bonding of seed crystals. Background Technology

[0002] Seed crystals are core components in crystal growth, semiconductor material preparation, and precision optical component processing. The quality of the hot-press bonding between the seed crystal and the crystal holder directly determines the stability of crystal growth, material yield, and device performance. Vacuum hot-press furnaces, as key equipment for achieving seed crystal hot-press bonding, must simultaneously meet requirements such as a high vacuum environment, uniform temperature field, stable pressure output, and convenient assembly and maintenance. Their structural design and performance directly affect the density, defect-free nature, and bonding strength of the bonding interface.

[0003] Currently, conventional vacuum hot press furnaces generally suffer from problems such as low exhaust efficiency, insufficient temperature control accuracy, poor pressurization stability, and inconvenient furnace assembly and disassembly. Conventional equipment mostly uses a single top evacuation method, which is difficult to quickly remove residual gas from the gap between the seed crystal and the crystal holder. This easily leads to the formation of pores and inclusions during hot pressing, and also causes material oxidation, reducing the bonding quality. The heating system is mostly unilateral or peripheral heating, resulting in poor temperature field uniformity and inability to achieve precise temperature control, which easily causes local overheating. The pressurization mechanism is prone to force offset and uneven pressure transmission, resulting in inconsistent stress on the bonding surface. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a vacuum hot press furnace with an exhaust structure for hot pressing bonding of seed crystals. This solves the problems of a single exhaust method, difficulty in quickly removing residual gas from the gap between the seed crystal and the crystal support bonding surface, easy formation of pores and inclusions during hot pressing, and material oxidation, which reduces the bonding quality.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a vacuum hot press furnace with an exhaust structure for hot pressing and bonding of seed crystals, comprising:

[0006] The cabinet has support rods fixedly connected to both sides of its top. A crossbeam is fitted onto the top of each support rod. A pressure block is located at the bottom center of the crossbeam. A base is fixedly connected to the top center of the cabinet. A hot press furnace is located at the top of the base. A top cover is connected to the top of the hot press furnace via a locking mechanism. A main exhaust flange interface is located on the outer periphery of the top of the top cover. The bottom of the outer wall of the hot press furnace is connected to the base via a plug-in assembly. A jacket is located in the middle of the hot press furnace. A heating tube is located in the middle of the jacket. A through groove is opened in the middle of the jacket.

[0007] The cabinet contains symmetrically arranged upper and lower pressure rods. A hydraulic cylinder is installed inside the cabinet. The drive end of the hydraulic cylinder is connected to the bottom end of the lower pressure rod. An upper pressure plate is fixedly connected to the bottom end of the upper pressure rod. Multiple exhaust channels are opened on the upper pressure plate. A lower pressure plate is fixedly connected to the top end of the lower pressure rod. Both the upper and lower pressure plates have latex pressure heads on their working surfaces. Multiple exhaust grooves are opened above the lower pressure plate, and the exhaust grooves are evenly distributed radially from the center of the lower pressure plate to the edge. Multiple auxiliary air extraction ports are opened on the outer periphery of the bottom end of the lower pressure plate, and the auxiliary air extraction ports are connected to the exhaust grooves.

[0008] Preferably, the plug-in assembly includes multiple slots located at the top of the base, a collar is threadedly connected to the bottom of the outer wall of the hot press furnace, a sliding groove is provided at the bottom of the outer wall of the hot press furnace and the sliding groove is located below the thread, a movable ring is slidably connected in the sliding groove, the movable ring is sleeved on the outer wall of the hot press furnace, and multiple plug blocks are fixedly connected to the outer periphery of the bottom of the hot press furnace.

[0009] Preferably, the top end of the upper pressure rod penetrates through the top cover, and the top end of the top cover is provided with a top block, the bottom end of the top block being in contact with the top end of the upper pressure rod.

[0010] Preferably, the exhaust groove has a trapezoidal cross-section that is wider at the bottom and narrower at the top, and the edges of the exhaust groove are all rounded with a radius of R0.1 to R0.2 mm. The bottom of the exhaust groove is provided with an inverted conical transition section, and the cone angle of the inverted conical transition section is 30° to 60°.

[0011] Preferably, it also includes a vacuum exhaust system, which includes: a main exhaust pipeline, an auxiliary exhaust pipeline, and a vacuum unit. One end of the main exhaust pipeline is connected to the main exhaust flange interface at the top of the top cover, and the other end of the main exhaust pipeline is connected to the vacuum unit. One end of the auxiliary exhaust pipeline is connected to the auxiliary exhaust interface at the bottom of the lower pressure plate, and the other end of the auxiliary exhaust pipeline is connected to the main exhaust pipeline. Both the main exhaust flange interface and the auxiliary exhaust interface are KF / ISO hot press furnace standard interfaces.

[0012] Preferably, it also includes a heating temperature control system, which includes: a graphite heating element embedded in the upper and lower pressure plates, a platinum-rhodium thermocouple, and a PID hot press furnace temperature controller. The platinum-rhodium thermocouple is respectively disposed on the working surface side of the upper and lower pressure plates, and the PID hot press furnace temperature controller is electrically connected to the graphite heating element and the platinum-rhodium thermocouple.

[0013] A method of using a vacuum hot press furnace with an exhaust structure for hot pressing bonding of seed crystals includes the following steps:

[0014] Step 1: Place the hot press furnace in the middle of the base and fix it in the middle of the base using the plug-in assembly;

[0015] Step 2: Release the clips, remove the top cover and upper pressure rod, and then place the seed crystal into the middle of the jacket;

[0016] Step 3: Install the pressure rod and top cover in sequence and lock the buckle. Then install the crossbeam to the top of the support rod, so that the pressure block in the middle of the bottom end of the crossbeam abuts against the top block.

[0017] Step 4: Start the vacuum exhaust system to extract air from the cabinet, and at the same time open the auxiliary exhaust port to quickly extract the gas from the cabinet.

[0018] Step 5: Start the heating temperature control system. The PID temperature controller controls the graphite heating element embedded in the upper and lower pressure plates, as well as the heating tube, to be powered on and generate heat.

[0019] Preferably, in step one, after placing the hot press furnace in the middle of the base, the moving ring is pulled down so that the insert block is inserted into the slot, then the moving ring is rotated, and then the collar is rotated down and tightened.

[0020] Preferably, after installing the crossbeam to the top of the support rod in step three, the crossbeam is fixed to the top of the support rod by a threaded sleeve, and the threaded sleeve in the middle of the top of the crossbeam is rotated so that the pressure block abuts against the top block.

[0021] Preferably, after starting the heating and temperature control system in step five, the pressurization mechanism is started simultaneously, controlling the hydraulic cylinder to drive the lower pressure rod to push the lower pressure plate upward, so that the adhesive initially wets the bonding surface between the seed crystal and the crystal support at high temperature.

[0022] Working principle: During operation, first align the bottom insert block of the hot press furnace with the base slot, slide down the moving ring to complete the insertion, and tighten the collar to secure it firmly. After placing the seed crystal coated with adhesive and the crystal holder coaxially into the center of the furnace body jacket, install the upper pressure rod, lock the top cover and crossbeam in sequence, so that the crossbeam pressure block and the top block of the upper pressure rod are in tight contact. Then, start the vacuum exhaust system, extract the gas from the entire furnace cavity through the main exhaust pipe of the main exhaust flange interface of the top cover, and at the same time open the auxiliary exhaust interface at the bottom of the lower pressure plate, using the lower pressure plate to radiate gas from the center to the edge. The furnace features evenly distributed exhaust grooves with a trapezoidal cross-section (wider at the bottom and narrower at the top) and a 30°–60° inverted conical transition section with rounded corners of R0.1–R0.2mm. These, combined with the equal-diameter exhaust channels of the upper pressure plate, simultaneously and dual-path exhaust cleans the furnace of air and residual gas between the seed crystal and the crystal support interface, rapidly reducing the furnace vacuum to ≤1×10⁻²Pa and preventing oxidation and porosity issues. Next, the heating and temperature control system is activated, relying on the graphite heating elements (resistance wire heating) embedded in the upper and lower pressure plates and the heating tubes within the jacket for bidirectional heating. Uniform heating is achieved through real-time temperature data acquisition by platinum-rhodium thermocouples attached to the working surface of the pressure plate, which is then transmitted to a PID temperature controller. This enables high-precision temperature control of ±1℃, while maintaining a very low temperature gradient across the entire heating area. This ensures a stable temperature field without localized overheating, preventing variations in adhesive thickness, adhesive spots, or curing degree. Simultaneously, a hydraulic cylinder inside the cabinet drives a lower pressure rod to push the lower pressure plate upwards. The upper pressure rod cannot move upwards due to contact between the top block and the crossbeam pressure block, thus creating a stable and uniform pressure between the latex flexible pressure heads of the upper and lower pressure plates. The force is evenly transmitted to the bonding surface between the seed crystal and the crystal holder, allowing the adhesive to fully wet the bonding surface under high temperature, high vacuum, high pressure, and precise temperature control and uniform pressing environment. This ensures the consistency of the adhesive layer formation and fundamentally avoids serious consequences such as seed crystal ablation, hexagonal voids, or even phase transformation caused by poor back-side thermal conductivity during subsequent crystal growth. Ultimately, a defect-free and high-strength hot-press bonding between the seed crystal and the crystal holder is achieved. The entire process is structurally stable, with efficient venting, precise temperature control and pressurization, significantly improving the yield and quality of seed crystal hot-press bonding.

[0023] This invention provides a vacuum hot press furnace with an exhaust structure for hot pressing and bonding of seed crystals. It has the following beneficial effects:

[0024] 1. This invention adopts a dual-path synchronous exhaust structure with main and auxiliary exhaust, combined with the exhaust channel of the upper pressure plate and the radial trapezoidal exhaust groove of the lower pressure plate. It can quickly remove residual gas inside the furnace cavity and the gap between the seed crystal and the crystal support, and stabilize the vacuum degree in the furnace to ≤1×10⁻²Pa. This avoids defects such as oxidation, porosity and inclusions during hot pressing from the root. The exhaust groove of the lower pressure plate adopts a trapezoidal cross section with a wider bottom and a narrower top, a 30°~60° inverted conical transition section and a rounded corner of R0.1~R0.2mm. This ensures smooth exhaust without dead corners and does not damage the surface of the seed crystal. At the same time, it reduces airflow resistance and stress concentration, greatly improves the density and integrity of the hot pressing joint of the seed crystal, and effectively improves the product qualification rate and long-term reliability.

[0025] 2. This invention features an embedded graphite heating element in the upper and lower pressure plates, which, together with the jacket heating tube, provides uniform heating. A platinum-rhodium thermocouple collects the working surface temperature in real time, ensuring a stable temperature field without localized overheating. This meets the precise temperature requirements of seed crystal hot pressing. The hydraulic pressurization mechanism works in conjunction with the crossbeam limiting structure to achieve vertical pressure and uniform force distribution, ensuring stable pressure transmission and consistent force on the joint surface. It is also equipped with a plug-in assembly. Through the cooperation of plug blocks, slots, moving rings, and collars, the hot press furnace and base can be quickly positioned, plugged in, and locked. This facilitates easy assembly and disassembly, precise positioning, shortens furnace loading and debugging time, and improves equipment efficiency. Attached Figure Description

[0026] Figure 1 is a perspective view of the present invention;

[0027] Figure 2 is a schematic diagram of the base of the present invention;

[0028] Figure 3 is a schematic diagram of the upper pressure rod of the present invention;

[0029] Figure 4 is Figure 3 Magnification at point A in the middle;

[0030] Figure 5 is a schematic diagram of the present invention.

[0032] The components are as follows: 1. Cabinet; 2. Support rod; 3. Crossbeam; 4. Hot press furnace; 5. Base; 6. Top cover; 7. Thread; 8. Slide groove; 9. Slot; 10. Insert block; 11. Moving ring; 12. Collar; 13. Jacket; 14. Upper pressure rod; 15. Top block; 16. Lower pressure rod; 17. Heating tube; 18. Upper pressure plate; 19. Lower pressure plate; 20. Through groove; 21. Exhaust groove; 22. Exhaust channel. Detailed Implementation

[0033] 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 embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0034] Example:

[0035] As one aspect of the present invention, please refer to the appendix. Figure 1 -Appendix Figure 4 This invention provides a vacuum hot press furnace with an exhaust structure for hot pressing and bonding of seed crystals, comprising:

[0036] Cabinet 1 has support rods 2 fixedly connected to both sides of its top. Threaded sleeves are connected to the top of each support rod 2 via threaded grooves. After installing the crossbeam 3 onto the top of the support rod 2, the threaded sleeves are screwed onto the top of the support rod 2, thus fixing the crossbeam 3 to the support rod 2. The crossbeam 3 is fitted onto the top of the support rod 2. A pressure block is located at the center of the bottom end of the crossbeam 3. The pressure block is also connected to the crossbeam 3 via a threaded sleeve, which is located at the top of the crossbeam 3. Rotating the threaded sleeve controls the pressure block. The lifting mechanism is as follows: a base 5 is fixedly connected to the top center of the cabinet 1; a hot press furnace 4 is mounted on the top of the base 5; a top cover 6 is connected to the top of the hot press furnace 4 via a latch; the top cover 6 can be removed from the top of the hot press furnace 4 by unlocking the latch; a main exhaust flange interface is provided on the outer periphery of the top of the top cover 6; air is extracted from the hot press furnace 1 through the main exhaust flange interface on the top of the top cover 6; simultaneously, the auxiliary exhaust interface on the side periphery of the lower pressure plate 19 is opened, and auxiliary exhaust is started simultaneously to quickly extract the atmospheric air from the furnace chamber to the process air. The required initial vacuum degree is ≤1×10⁻²Pa. Multiple slots 9 are provided at the top of the base 5 for inserting plugs 10. A collar 12 is connected to the bottom of the outer wall of the hot press furnace 4 via a thread 7. A groove 8 is provided at the bottom of the outer wall of the hot press furnace 4, located below the thread 7. A movable ring 11 is slidably connected within the groove 8. The movable ring 11 can slide within the groove 8. When the movable ring 11 is moved to the bottom of the groove 8, rotating the movable ring 11 allows the plug 10 to be inserted. Inside the slot 9, rotate the collar 12 and tighten it, so that the collar 12 can limit the moving ring 11 and prevent the moving ring 11 from moving in the slide groove 8. The moving ring 11 is sleeved on the outer wall of the hot press furnace 4. Multiple inserts 10 are fixedly connected to the bottom outer periphery of the hot press furnace 4. A jacket 13 is provided in the middle of the hot press furnace 4. A heating tube 17 is provided in the middle of the jacket 13. A through groove 20 is opened in the middle of the jacket 13. By providing the through groove 20, the heat of the heating tube 17 can be directed to the central area.

[0037] The upper pressure rod 14 and lower pressure rod 16 are symmetrically arranged. A hydraulic cylinder is installed inside the cabinet 1. The driving end of the hydraulic cylinder is connected to the bottom end of the lower pressure rod 16. The hydraulic cylinder can push the lower pressure rod 16 upward, thereby moving the lower pressure plate 19 to cooperate with the upper pressure plate 18 and apply pressure to the seed crystal. The bottom end of the upper pressure rod 14 is fixedly connected to the upper pressure plate 18. The upper pressure plate 18 has multiple exhaust channels 22. The upper and lower ends of the exhaust channels 22 respectively penetrate the top surface and the working surface of the upper pressure plate 18. The exhaust channel 22 is a through hole of equal diameter, with a diameter of 2-5 mm, and its lower end is flush with the working surface of the upper pressure plate 18. The top end of the lower pressure rod 16 is fixedly connected to the lower pressure plate 19. Both the upper pressure plate 18 and the lower pressure plate 19 are provided with latex pressure heads on their working surfaces. Multiple exhaust grooves 21 are opened on the upper part of the lower pressure plate 19, and the exhaust grooves 21 are evenly distributed radially from the center of the lower pressure plate 19 to the edge. Multiple auxiliary air extraction ports are opened on the outer periphery of the bottom end of the lower pressure plate 19, and the auxiliary air extraction ports are connected to the exhaust grooves 21.

[0038] The top of the upper pressure rod 14 penetrates through the top cover 6, and a top block 15 is provided at the top of the top cover 6. The bottom end of the top block 15 contacts the top of the upper pressure rod 14. When the hydraulic cylinder pushes the lower pressure rod 16 upward, it can move the lower pressure plate 19 and make contact with the upper pressure plate 18. Then it pushes the upper pressure rod 14 to move, and the top of the upper pressure rod 14 contacts the pressure block, thereby preventing the upper pressure rod 14 from moving. This allows the latex flexible pressure heads of the upper pressure plate 18 and the lower pressure plate 19 to apply pressure to the seed crystal. The cross-section of the venting groove 21 is a trapezoid with a wider bottom and a narrower top. The edges of the venting groove 21 are all rounded with a radius of R0.1 to R0.2 mm. The bottom of the venting groove 21 is provided with an inverted conical transition section with a cone angle of 30° to 60°.

[0039] It also includes a vacuum exhaust system, which includes a main exhaust pipeline, an auxiliary exhaust pipeline, and a vacuum unit. One end of the main exhaust pipeline is connected to the main exhaust flange interface on the top of the top cover 6, and the other end of the main exhaust pipeline is connected to the vacuum unit. One end of the auxiliary exhaust pipeline is connected to the auxiliary exhaust interface at the bottom of the lower pressure plate 19, and the other end of the auxiliary exhaust pipeline is connected to the main exhaust pipeline. Both the main exhaust flange interface and the auxiliary exhaust interface are KF / ISO hot press furnace standard interfaces.

[0040] It also includes a heating and temperature control system, which includes: a graphite heating element embedded in the upper pressure plate 18 and the lower pressure plate 19, a platinum-rhodium thermocouple, and a PID hot press furnace temperature controller. The graphite heating element is embedded and encapsulated inside the upper pressure plate 18 and the lower pressure plate 19, and is evenly distributed below the working surface of the pressure plate. It is used to uniformly heat the seed crystal, crystal support, and bonding layer in both directions. The graphite heating element, together with the PID temperature controller, achieves high-precision control of the heating temperature and controls the heating temperature gradient of the entire area within an extremely low range. The platinum-rhodium thermocouple is respectively set on the working surface side of the upper pressure plate 18 and the lower pressure plate 19 to directly collect the real temperature of the working surface in real time and transmit the temperature signal to the PID temperature controller in real time. The PID hot press furnace temperature controller is electrically connected to the graphite heating element and the platinum-rhodium thermocouple. It can set the heating rate, control the constant temperature accuracy, alarm the over-temperature and store the process curve. The temperature control accuracy reaches ±1℃, ensuring a stable temperature field and no local overheating during the hot pressing bonding process of the seed crystal. The temperature gradient in the whole area is extremely low, avoiding differences in adhesive layer thickness, adhesive spots or curing degree, and preventing problems such as seed crystal ablation, hexagonal voids or even phase transformation during the subsequent crystal growth process.

[0041] As another aspect of the present invention, please refer to the appendix. Figure 1 -Appendix Figure 5 A method of using a vacuum hot press furnace with an exhaust structure for hot pressing bonding of seed crystals includes the following steps:

[0042] Step 1: Install the hot press furnace 4. Place the hot press furnace 4 in the middle of the base 5 and fix the hot press furnace 4 in the middle of the base 5 through the plug-in assembly. Pull the moving ring 11 down so that the plug block 10 is inserted into the slot 9. Then rotate the moving ring 11 and rotate the collar 12 down and tighten it to ensure that the equipment is stable, without shaking or deviation during the pressurization and heating process.

[0043] Step 2: Place the seed crystal, release the buckle, remove the top cover 6 and the upper pressure rod 14, then place the seed crystal into the middle of the jacket 13, and accurately place the seed crystal coated with adhesive and the crystal support assembly into the middle of the jacket 13, so that the seed crystal, adhesive layer and crystal support are coaxially aligned and aligned with the center positions of the upper pressure plate 18 and the lower pressure plate 19, to ensure uniform pressure and unobstructed exhaust path.

[0044] Step 3: Seal. Install the pressure rod 14 and the top cover 6 in sequence and lock the buckle. Then install the crossbeam 3 to the top of the support rod 2, so that the pressure block at the bottom center of the crossbeam 3 abuts against the top block 15. Fix the crossbeam 3 to the top of the support rod 2 with the threaded sleeve, and rotate the threaded sleeve at the top center of the crossbeam 3 so that the pressure block abuts against the top block 15.

[0045] Step 4: Start the vacuum exhaust system to evacuate the air inside cabinet 1. At the same time, open the auxiliary exhaust port. By operating the main exhaust and auxiliary exhaust simultaneously, quickly extract all the air in the furnace and the gas in the gap between the seed crystal and the crystal support interface, so that the furnace reaches the vacuum level required by the process and eliminates the hidden dangers of oxidation and porosity.

[0046] Step 5: Activate the heating and temperature control system. The graphite heating element embedded in the upper pressure plate 18 and lower pressure plate 19, as well as the heating tube 17, are powered on and heated through the PID temperature controller. The heating temperature is precisely controlled and the temperature gradient of the entire area is kept within an extremely low range to ensure uniform curing of the adhesive layer. Simultaneously, the pressurization mechanism is activated, and the hydraulic cylinder drives the lower pressure rod 16 to push the lower pressure plate 19 upward. The pressure is evenly transmitted to the bonding surface between the seed crystal and the crystal support through the latex flexible pressure head, so that the adhesive initially wets the bonding surface between the seed crystal and the crystal support at high temperature. Under the dual effects of precise temperature control and uniform pressure, the consistency of adhesive layer formation is ensured, fundamentally avoiding serious consequences such as seed crystal ablation, hexagonal voids, or even phase transformation caused by poor thermal conductivity during subsequent crystal growth.

[0047] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A vacuum hot press furnace with exhaust structure for seed crystal hot press bonding, characterized by, include: Cabinet (1), with support rods (2) fixedly connected to both sides of the top of the cabinet (1), a crossbeam (3) sleeved on the top of the support rod (2), a pressure block set in the middle of the bottom end of the crossbeam (3), a base (5) fixedly connected to the middle of the top of the cabinet (1), a hot press furnace (4) set on the top of the base (5), a top cover (6) connected to the top of the hot press furnace (4) by a locking buckle, a main exhaust flange interface set on the outer periphery of the top of the top cover (6), the bottom end of the outer wall of the hot press furnace (4) connected to the base (5) by a plug-in assembly, a jacket (13) set in the middle of the hot press furnace (4), a heating pipe (17) set in the middle of the jacket (13), and a through groove (20) opened in the middle of the jacket (13). The upper pressure rod (14) and lower pressure rod (16) are symmetrically arranged. A hydraulic cylinder is provided inside the cabinet (1). The driving end of the hydraulic cylinder is connected to the bottom end of the lower pressure rod (16). An upper pressure plate (18) is fixedly connected to the bottom end of the upper pressure rod (14). Multiple exhaust channels (22) are opened on the upper pressure plate (18). A lower pressure plate (19) is fixedly connected to the top end of the lower pressure rod (16). Latex flexible pressure heads are provided on the working surfaces of the upper pressure plate (18) and the lower pressure plate (19). Multiple exhaust grooves (21) are opened above the lower pressure plate (19). The exhaust grooves (21) are radially distributed from the center of the lower pressure plate (19) to the edge. Multiple auxiliary air extraction ports are opened on the outer periphery of the bottom end of the lower pressure plate (19). The auxiliary air extraction ports are connected to the exhaust grooves (21).

2. The vacuum hot press furnace with exhaust structure for seed crystal hot pressing bonding according to claim 1, characterized in that, The plug-in assembly includes multiple slots (9) located at the top of the base (5). The bottom of the outer wall of the hot press furnace (4) is connected to a collar (12) by a thread (7). The bottom of the outer wall of the hot press furnace (4) is provided with a sliding groove (8), and the sliding groove (8) is located below the thread (7). A movable ring (11) is slidably connected in the sliding groove (8). The movable ring (11) is sleeved on the outer wall of the hot press furnace (4). Multiple plug blocks (10) are fixedly connected to the outer periphery of the bottom of the hot press furnace (4).

3. The vacuum hot press furnace with exhaust structure for seed crystal hot pressing bonding according to claim 1, characterized in that, The top end of the upper pressure rod (14) penetrates the top cover (6), and the top end of the top cover (6) is provided with a top block (15), the bottom end of the top block (15) is in contact with the top end of the upper pressure rod (14).

4. A vacuum hot press furnace with an exhaust structure for hot pressing and bonding of seed crystals according to claim 1, characterized in that, The exhaust groove (21) has a cross-section that is wider at the bottom and narrower at the top. The groove edges of the exhaust groove (21) are all rounded with a radius of R0.1 to R0.2 mm. The bottom of the exhaust groove (21) is provided with an inverted conical transition section with a cone angle of 30° to 60°.

5. A vacuum hot press furnace with an exhaust structure for hot pressing and bonding of seed crystals according to claim 1, characterized in that, It also includes a vacuum exhaust system, which includes a main exhaust pipeline, an auxiliary exhaust pipeline and a vacuum unit. One end of the main exhaust pipeline is connected to the main exhaust flange interface at the top of the top cover (6), and the other end of the main exhaust pipeline is connected to the vacuum unit. One end of the auxiliary exhaust pipeline is connected to the auxiliary exhaust interface at the bottom of the lower pressure plate (19), and the other end of the auxiliary exhaust pipeline is connected to the main exhaust pipeline. Both the main exhaust flange interface and the auxiliary exhaust interface are KF / ISO hot press furnace standard interfaces.

6. A vacuum hot press furnace with an exhaust structure for hot pressing and bonding of seed crystals according to claim 1, characterized in that, It also includes a heating temperature control system, which includes: a graphite heating element, a platinum-rhodium thermocouple, and a PID hot press furnace temperature controller embedded in the upper pressure plate (18) and the lower pressure plate (19). The platinum-rhodium thermocouple is respectively located on the working surface side of the upper pressure plate (18) and the lower pressure plate (19). The PID hot press furnace temperature controller is electrically connected to the graphite heating element and the platinum-rhodium thermocouple. This heating temperature control system can achieve high-precision control of heating temperature and control the heating temperature gradient of the entire area within an extremely low range to avoid differences in adhesive layer thickness, adhesive spots, or curing degree.

7. A method of using a vacuum hot press furnace with an exhaust structure for hot pressing and bonding of seed crystals, comprising using the vacuum hot press furnace with an exhaust structure for hot pressing and bonding of seed crystals as described in any one of claims 1-7, characterized in that, Includes the following steps: Step 1: Place the hot press (4) in the middle of the base (5) and fix the hot press (4) in the middle of the base (5) by means of the plug-in assembly; Step 2: Release the buckle, remove the top cover (6) and the upper pressure rod (14), and then put the seed crystal into the middle of the jacket (13); Step 3: Install the upper pressure rod (14) and the top cover (6) in sequence and lock the buckle. Then install the crossbeam (3) to the top of the support rod (2) and make the pressure block at the bottom center of the crossbeam (3) abut against the top block (15). Step 4: Start the vacuum exhaust system to extract air from the cabinet (1), and at the same time open the auxiliary exhaust port to quickly extract the gas from the cabinet (1); Step 5: Start the heating temperature control system. The graphite heating element embedded in the upper pressure plate (18) and lower pressure plate (19) and the heating tube (17) are powered on and heated by the PID temperature controller to accurately control the heating temperature and the temperature gradient of the whole area, so as to ensure the uniformity of the adhesive layer curing.

8. The method of using a vacuum hot press furnace with an exhaust structure for seed crystal hot pressing according to claim 7, characterized in that, After placing the hot press furnace (4) in the middle of the base (5) in step one, pull the moving ring (11) down and insert the insert block (10) into the slot (9), then rotate the moving ring (11), and then rotate the collar (12) down and tighten it.

9. The method of using a vacuum hot press furnace with an exhaust structure for seed crystal hot pressing according to claim 7, characterized in that, In step three, after the crossbeam (3) is installed on the top of the support rod (2), the crossbeam (3) is fixed to the top of the support rod (2) by the threaded sleeve, and the threaded sleeve in the middle of the top of the crossbeam (3) is rotated so that the pressure block and the top block (15) abut against each other.

10. A method of using a vacuum hot press furnace with an exhaust structure for seed crystal hot pressing according to claim 7, characterized in that, In step five, after starting the heating and temperature control system, the pressurization mechanism is started simultaneously. The hydraulic cylinder drives the lower pressure rod (16) to push the lower pressure plate (19) upward. The pressure is uniformly transmitted to the joint surface between the seed crystal and the crystal support through the latex flexible pressure head, so that the adhesive initially wets the joint surface between the seed crystal and the crystal support at high temperature. Under the dual effect of precise temperature control and uniform pressure, the consistency of the adhesive layer is ensured, and problems such as seed crystal ablation, hexagonal voids or even phase transformation caused by poor thermal conductivity are avoided in the subsequent crystal growth process.

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