A vacuum bonding device for SiC wafers

Abstract

The invention discloses a vacuum bonding device for SiC wafers, which solves the problem of how to automatically complete the bonding of two SiC wafers with high quality. On the bottom surface of a vacuum sealed box (4), a lower water-cooled support platform (5), a lower heat isolation plate (6), a lower electric heating plate (7), a lower graphite plate (8), a SiC wafer (9), an upper graphite plate (10), an upper electric heating plate (11), an upper heat isolation plate (12), an upper water-cooled pressure plate (13) and a pressure transmission plate (14) are arranged in sequence from bottom to top. A hemispherical groove (23) is arranged on the pressure transmission plate (14), and a hemispherical pressure head (24) with a handle is arranged in the hemispherical groove. A force transmission shaft (15) is connected to the handle arranged on the top surface of the hemispherical pressure head, and the upper end of the force transmission shaft passes through the top surface of the vacuum sealed box (4) and is connected to a cylinder (18). The invention realizes high-quality bonding of two wafers under vacuum, temperature and pressure required by the process.

Description

Technical Field

[0001] The invention relates to a bonding device, in particular to a vacuum bonding device for SiC wafers. Background Art

[0002] The vacuum bonding process of SiC wafers is as follows: after high-temperature treatment, the SiC wafers are bonded together with an adhesive. Under vacuum and in a stable temperature field, pressure is applied to bond the two SiC wafers together. This bonding technology is also called silicon-silicone bonding technology for SiC wafers. The specific process of silicon-silicone bonding is as follows: (1) The polished SiC wafers (oxidized or unoxidized) are first soaked in a chemical solution; (2) At room temperature, the adhesive is evenly applied to the polished surface of a SiC wafer; (3) The polished surface of another SiC wafer is bonded to the wafer coated with the adhesive; (4) The two preliminarily bonded SiC wafers are placed in a fixture; (5) The graphite fixture containing the bonded SiC wafers is placed in a vacuum (or nitrogen) atmosphere. (6) The upper and lower heating plate platforms are powered on for heating, so that the temperature of the graphite fixture is stabilized at 500 degrees Celsius; (6) The graphite fixture is pressurized by a press machine to maintain a certain pressure. After several hours of high-temperature pressurization treatment, the two SiC wafers are bonded together. In the above-mentioned high-temperature pressurization bonding process, there are two main factors that affect the quality of the bonding of the two SiC wafers. One is the parallelism of the upper and lower pressurization platforms of the fixture. Only with high-quality parallelism can high-quality bonding of the two SiC wafers be achieved. The second is the uniformity of the heating temperature of the upper and lower pressurization platforms of the fixture. According to the process requirements, the heating temperature of the upper and lower pressurization platforms is 500 degrees Celsius, and the temperature uniformity must reach ±3°C. How to meet the above requirements is a technical problem that needs to be solved in equipment design. Summary of the invention

[0003] The invention provides a vacuum bonding device for SiC wafers, which solves the technical problem of how to automatically complete the bonding of two SiC wafers with high quality.

[0004] The present invention solves the above technical problems through the following technical solutions:

[0005] A vacuum bonding device for SiC wafers comprises a stand, a gantry support is arranged on the left side of the stand, a controller is arranged on the right side of the stand, a vacuum sealed box is arranged on the left side of the stand under the gantry support, a lower water-cooled support platform is arranged on the bottom of the box in the vacuum sealed box, a lower heat isolation plate is arranged on the lower water-cooled support platform, a lower electric heating plate is arranged on the lower heat isolation plate, a lower graphite plate is arranged on the lower electric heating plate, a SiC wafer piece bonded together is arranged on the lower graphite plate, an upper graphite plate is arranged on the SiC wafer piece, and an upper graphite plate is arranged on the upper graphite plate. An upper electric heating plate is arranged on the upper electric heating plate, an upper heat isolation plate is arranged on the upper heat isolation plate, an upper water-cooled pressing plate is arranged on the upper top surface of the upper water-cooled pressing plate, a pressure transmission plate is arranged on the pressure transmission plate, a hemispherical groove is arranged on the pressure transmission plate, a hemispherical pressure head with a handle rod is arranged in the hemispherical groove, a force transmission shaft is connected to the handle rod arranged on the top surface of the hemispherical pressure head, the upper end of the force transmission shaft passes through the top surface of the vacuum sealed box and is connected to the force sensor, a cylinder is arranged on the top beam of the gantry bracket, and the lower end of the downwardly extending output shaft of the cylinder is connected to the upper end of the force sensor.

[0006] A water-cooling sealing sleeve is arranged in the through hole of the force transmission shaft on the top surface of the vacuum sealed box, and the force transmission shaft is arranged in the water-cooling sealing sleeve; a lower water-cooling chamber is arranged in the lower water-cooling support platform, and a lower water-cooling chamber water inlet and a lower water-cooling chamber water outlet are respectively arranged on the lower bottom surface of the lower water-cooling support platform, and a lower water-cooling chamber water outlet pipe is connected to the lower water-cooling chamber water outlet, the lower water-cooling chamber water outlet pipe is arranged in the lower water-cooling chamber, and the upper port of the lower water-cooling chamber water outlet pipe is arranged at the top end of the lower water-cooling chamber; An upper water cooling chamber is arranged in the pressing plate, the water inlet of the upper water cooling chamber is arranged at the lower end of the upper water cooling chamber, and the water outlet of the upper water cooling chamber is arranged at the upper end of the upper water cooling chamber; the structure of the lower electric heating plate is the same as that of the upper electric heating plate, and an inner electric heating resistance belt, a middle electric heating resistance belt and an outer electric heating resistance belt are arranged on the lower electric heating plate respectively, and the three resistance belts are evenly arranged on the lower electric heating plate, and they are all Cr20Ni30 thin sheet resistance belts with a width of 6 mm and a thickness of 0.03 mm.

[0007] A water-cooled sealing sleeve cooling water chamber is arranged in the sealing base of the water-cooled sealing sleeve. Between the sealing base and the force transmission shaft, O-rings, O-ring pressure rings, shaft seals and pressure plates are arranged in sequence from bottom to top. The pressure plate is fixedly connected to the sealing base.

[0008] The present invention realizes high-quality bonding of two wafers under vacuum, temperature and specific pressure required by the process, has high bonding quality, and is easy to operate and maintain the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a schematic diagram of the structure of the present invention;

[0010] Figure 2 It is a schematic diagram of the furnace structure of the present invention;

[0011] Figure 3 It is a schematic structural diagram of the water-cooling sealing sleeve 16 of the present invention;

[0012] Figure 4 It is a schematic structural diagram of the lower electric heating plate 7 of the present invention. DETAILED DESCRIPTION

[0013] The present invention is described in detail below in conjunction with the accompanying drawings:

[0014] A vacuum bonding device for SiC wafers, comprising a stand 1, a gantry support 3 is arranged on the left side of the stand 1, a controller 2 is arranged on the right side of the stand 1, a vacuum sealed box 4 is arranged on the left side of the stand 1 under the gantry support 3, a lower water-cooled support platform 5 is arranged on the bottom of the vacuum sealed box 4, a lower heat isolation plate 6 is arranged on the lower water-cooled support platform 5, a lower electric heating plate 7 is arranged on the lower heat isolation plate 6, a lower graphite plate 8 is arranged on the lower electric heating plate 7, a SiC wafer 9 bonded together is arranged on the lower graphite plate 8, an upper graphite plate 10 is arranged on the SiC wafer 9, an upper electric heating plate 11 is arranged on the upper graphite plate 10, an upper heat isolation plate 12 is arranged on the upper electric heating plate 11, and a lower heat isolation plate 12 is arranged on the upper heat isolation plate 12. An upper water-cooled pressing plate 13 is provided, a pressure transmission plate 14 is provided on the upper top surface of the upper water-cooled pressing plate 13, a hemispherical groove 23 is provided on the pressure transmission plate 14, a hemispherical pressure head 24 with a handle rod is provided in the hemispherical groove 23, a force transmission shaft 15 is connected to the handle rod provided on the top surface of the hemispherical pressure head 24, the upper end of the force transmission shaft 15 passes through the top surface of the vacuum sealed box 4 and is connected to the force sensor 17, a cylinder 18 is provided on the top beam of the gantry bracket 3, the lower end of the downwardly extending output shaft of the cylinder 18 is connected to the upper end of the force sensor 17, a multi-layer graphite plate can be provided between the lower electric heating plate 7 and the upper electric heating plate 11, and two pre-bonded wafers can be provided between two adjacent graphite plates, so as to achieve the purpose of bonding multiple groups of wafers in sequence.

[0015] A water-cooling sealing sleeve 16 is arranged in the through hole of the force transmission shaft 15 on the top surface of the vacuum sealed box 4, and the force transmission shaft 15 is arranged in the water-cooling sealing sleeve 16; a lower water-cooling chamber 19 is arranged in the lower water-cooling support platform 5, and a lower water-cooling chamber water inlet 20 and a lower water-cooling chamber water outlet 21 are respectively arranged on the lower bottom surface of the lower water-cooling support platform 5, and a lower water-cooling chamber water outlet pipe 22 is connected to the lower water-cooling chamber water outlet 21, and the lower water-cooling chamber water outlet pipe 22 is arranged in the lower water-cooling chamber 19, and the upper port of the lower water-cooling chamber water outlet pipe 22 is arranged at the top of the lower water-cooling chamber 19, so that the lower water-cooling chamber 19 is always filled with cooling water; an upper water-cooling chamber 25 is arranged in the upper water-cooling press plate 13, and the upper water-cooling chamber 25 The water inlet is arranged at the lower end of the upper water cooling chamber 25, and the water outlet 26 of the upper water cooling chamber 25 is arranged at the upper end of the upper water cooling chamber 25, so that the upper water cooling chamber 25 is always filled with cooling water; the structure of the lower electric heating plate 7 is the same as that of the upper electric heating plate 11, and an inner electric heating resistance belt 33, a middle electric heating resistance belt 34 and an outer electric heating resistance belt 35 are arranged on the lower electric heating plate 7 respectively, and the three resistance belts are evenly arranged on the lower electric heating plate 7, and they are all Cr20Ni30 thin sheet resistance belts with a width of 6 mm and a thickness of 0.03 mm. The arrangement of the three resistance belts can be adjusted according to the temperature field generated on the lower electric heating plate 7 to achieve a temperature difference on the plate within 3 degrees Celsius.

[0016] A water-cooled sealing sleeve cooling water chamber 28 is arranged in the sealing base 27 of the water-cooled sealing sleeve 16. Between the sealing base 27 and the force transmission shaft 15, an O-ring 30, an O-ring pressure ring 32, a shaft seal 31 and a pressure plate 29 are arranged in sequence from bottom to top. The pressure plate 29 is fixedly connected to the sealing base 27, so as to achieve reliable sealing of the vacuum sealing box 4.

[0017] The present invention controls the pressurization system, the vacuum pumping system, the electric heating system and the cooling system respectively through the controller 2 to complete the bonding of the wafers; after the door of the vacuum sealed box 4 is closed, the vacuum sealed box 4 is evacuated to the process requirement value, and then the upper and lower heating work platforms are controlled by the controller 2 to be powered on and heated according to a specific heating process curve to stabilize the graphite plate at the temperature required by the process, and then the pressurization system is controlled by the controller 2 to pressurize according to a specific pressurization process curve to bond qualified SiC wafer products.

Claims

1. A vacuum bonding device for SiC wafers, comprising a stand (1), a gantry support (3) being arranged on the left side of the stand (1), and a controller (2) being arranged on the right side of the stand (1), characterized in that: A vacuum sealed box (4) is arranged on the left table surface of the stand (1) under the gantry support (3); a lower water-cooled support platform (5) is arranged on the bottom surface of the vacuum sealed box (4); a lower heat isolation plate (6) is arranged on the lower water-cooled support platform (5); a lower electric heating plate (7) is arranged on the lower heat isolation plate (6); a lower graphite plate (8) is arranged on the lower electric heating plate (7); a SiC wafer (9) bonded together is arranged on the lower graphite plate (8); an upper graphite plate (10) is arranged on the SiC wafer (9); an upper electric heating plate (11) is arranged on the upper graphite plate (10); an upper heat isolation plate ( 12), an upper water-cooled pressure plate (13) is arranged on the upper heat isolation plate (12), a pressure transmission plate (14) is arranged on the upper top surface of the upper water-cooled pressure plate (13), a hemispherical groove (23) is arranged on the pressure transmission plate (14), a hemispherical pressure head (24) with a handle is arranged in the hemispherical groove (23), a force transmission shaft (15) is connected to the handle arranged on the top surface of the hemispherical pressure head (24), the upper end of the force transmission shaft (15) passes through the top surface of the vacuum sealed box (4) and is connected to the force sensor (17), a cylinder (18) is arranged on the top beam of the gantry bracket (3), and the lower end of the output shaft of the cylinder (18) extending downward is connected to the force sensor The upper ends of the devices (17) are connected together; a water-cooling sealing sleeve (16) is arranged in the through hole of the force transmission shaft (15) on the top surface of the vacuum sealed box (4), and the force transmission shaft (15) is arranged in the water-cooling sealing sleeve (16); a lower water cooling chamber (19) is arranged in the lower water cooling support platform (5), a lower water cooling chamber water inlet (20) and a lower water cooling chamber water outlet (21) are respectively arranged on the lower bottom surface of the lower water cooling support platform (5), a lower water cooling chamber water outlet pipe (22) is connected to the lower water cooling chamber water outlet (21), the lower water cooling chamber water outlet pipe (22) is arranged in the lower water cooling chamber (19), and an upper end of the lower water cooling chamber water outlet pipe (22) is arranged in the lower water cooling chamber (19) ) at the top of the upper water-cooling press plate (13); an upper water-cooling chamber (25) is arranged in the upper water-cooling press plate (13); a water inlet of the upper water-cooling chamber (25) is arranged at the lower end of the upper water-cooling chamber (25); a water outlet (26) of the upper water-cooling chamber (25) is arranged at the upper end of the upper water-cooling chamber (25); the structure of the lower electric heating plate (7) is the same as that of the upper electric heating plate (11); an inner electric heating resistance belt (33), a middle electric heating resistance belt (34) and an outer electric heating resistance belt (35) are arranged on the lower electric heating plate (7), and the three resistance belts are evenly spaced on the lower electric heating plate (7), and they are all Cr20Ni30 thin sheet resistance belts with a width of 6 mm and a thickness of 0.03 mm.

2. A vacuum bonding device for SiC wafers according to claim 1, characterized in that: A water-cooled sealing sleeve cooling water chamber (28) is arranged in the sealing base (27) of the water-cooled sealing sleeve (16); an O-ring (30), an O-ring pressure ring (32), a shaft seal (31) and a pressure plate (29) are arranged in sequence from bottom to top between the sealing base (27) and the force transmission shaft (15); the pressure plate (29) and the sealing base (27) are fixedly connected together.

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