Double-sided heat dissipation, large-current and high-surge Schottky diode, packaging structure and preparation method

Abstract

The invention relates to a double-face heat dissipation, large-current and high-surge Schottky diode and a packaging structure, and belongs to the technical field of power semiconductor device packaging, the double-face heat dissipation, large-current and high-surge Schottky diode comprises a TK3 metal ceramic tube seat and an upper electrode, the TK3 metal ceramic tube seat comprises sealing rings, a lower electrode and a ceramic frame, the upper electrode extends to the sealing rings, and the lower electrode is arranged between the sealing rings; the ceramic frame is wound on the outer side of the sealing ring, and a chip sintering area is arranged between the upper electrode and the lower electrode. The TK3 metal ceramic shell used in the invention is formed by combining molybdenum, Al2O3 ceramic, 4J42 Kovar alloy and other materials with similar linear expansion coefficients, and a step-by-step assembly and synchronous welding process is adopted; according to the double-sided heat dissipation, large-current and high-surge Schottky diode, the gold-tin solder is adopted as a welding material, stress generated in the high-temperature sintering process of different materials is reduced, secondary melting possibly occurring in the packaging and using process is effectively prevented, and the reliability of the product assembling process is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of power semiconductor device packaging, and particularly relates to a double-sided heat dissipation, large-current and high-surge Schottky diode and a packaging structure and a preparation method thereof. BACKGROUND

[0002] At present, metal ceramic packaged power devices are in great demand in the fields of national defense such as aerospace, aviation, shipbuilding and weapons, and are required to have the characteristics of integration, low resistance, low thermal resistance, good impact resistance and high reliability, thereby providing protection for improving the reliability of the whole machine. In recent years, with the continuous advancement of satellite, cargo spaceship and space station projects, the matching power supply of each system has also been put forward with higher requirements, and gradually develops towards high voltage and high power. At the same time, the development trend of various power supplies is also putting forward higher requirements for the forward current capacity of silicon Schottky diodes, which needs to be expanded to 150A or even larger on the basis of the existing tens of A.

[0003] In the metal ceramic packaged power semiconductor discrete device, the product with the largest forward current is the Schottky diode. According to the relevant data at home and abroad, the maximum forward current can reach 120A, and the product model is 120LQ100. The 120LQ100 adopts the conventional SMD-1 type metal ceramic packaging, which is limited by the packaging limited cavity structure, the number of bonding wires, the shell electrode material and the like, and cannot continue to improve the current capacity, and has already failed to meet the requirements of high-power application occasions. SUMMARY

[0004] To solve the above problems, the technical scheme adopted by the application is: A packaging structure of a double-sided heat dissipation, large-current and high-surge Schottky diode, comprising a TK3 metal ceramic tube base and an upper electrode, the TK3 metal ceramic tube base comprising a sealing ring, a lower electrode and a ceramic frame, the upper electrode extending to between the sealing rings, the ceramic frame being arranged outside the sealing ring and used for isolating the upper electrode and the lower electrode and the two sides of the sealing ring, a chip sintering area being arranged between the upper electrode and the lower electrode, and the chip sintering area being used for sintering a silicon chip.

[0005] Further, the upper electrode is provided with a lead-out end, a gold plating layer is arranged outside the lead-out end, and the material of the lead-out end is copper-invar-copper.

[0006] Further, the ceramic frame is made of insulating material, and the material of the ceramic frame is Al2O3 ceramic.

[0007] Further, a gold plating layer is arranged outside the lower electrode, and the material of the lower electrode is metal molybdenum.

[0008] Further, the material of the sealing ring is 4J42 Kovar alloy material.

[0009] Further, the upper electrode is provided with a gold plating layer outside, and the material of the upper electrode is metal molybdenum.

[0010] Further, the size of the ceramic frame is 10.92*10.92mm.

[0011] Further, the shape of the lead-out end is a right-angle Z-shaped type, one end of which is connected with the upper electrode, the width of the lead-out end is 5.08mm, and the extension length of the distal end of the lead-out end is 1.65mm.

[0012] The application further provides a double-sided heat dissipation, large-current and high-surge Schottky diode, comprising the packaging structure of the double-sided heat dissipation, large-current and high-surge Schottky diode.

[0013] The application further provides a preparation method of the double-sided heat dissipation, large-current and high-surge Schottky diode, comprising the following steps: Step S1, chip making, adopting a conventional epitaxial plane Schottky process, using platinum-nickel alloy as a barrier metal for an N-type epitaxial wafer, and using a titanium-nickel-silver composite metal evaporation diffusion protection ring structure for the front surface / back surface of the chip, wherein the outermost layer is silver, used for providing a wire bonding or welding, the middle layer is nickel, used for establishing a barrier layer, and the innermost layer is titanium, used for constructing an adhesion layer; Step S2, chip assembly, placing the preheated TK3 metal ceramic tube seat in the heating area of the atmosphere protection eutectic die bonder, placing the second gold-tin alloy soldering sheet with the same size as the silicon chip in the chip sintering area, placing the Schottky diode silicon chip in the area where the second gold-tin alloy soldering sheet is melted, and simultaneously applying a certain pressure to fully remove the bubbles that may be generated after the second gold-tin alloy soldering sheet is melted, transferring the TK3 metal ceramic tube seat to the nitrogen-protected cooling area, and completing cooling; Step S3, sintering inspection, internally checking the assembled chip of step S2, if the inspection requirement is met, the next step is continued, and if the inspection requirement is not met, the product that does not meet the inspection requirement is removed; Step S4, chip sealing, placing the first gold-tin alloy soldering sheet with the same size as the upper electrode in the center position of the front surface of the silicon chip that has been sintered with the TK3 metal ceramic tube seat, placing the upper electrode of the pre-prepared gold-tin solder in the opening area of the TK3 metal ceramic tube seat, and transferring the assembled whole to the atmosphere protection sintering furnace for sealing.

[0014] Compared with the prior art, the present application has the following beneficial effects: 1. The present application provides a double-sided heat dissipation, large current, high surge Schottky diode and packaging structure and preparation method, the TK3 metal ceramic shell used in the present application is composed of materials with similar linear expansion coefficients such as molybdenum, Al2O3 ceramic and 4J42 Kovar alloy, and a step-by-step assembly and synchronous welding process is adopted; the double-sided heat dissipation, large current, high surge Schottky diode of the present application uses gold-tin solder as the welding material, which reduces the stress generated by different materials during high-temperature sintering, effectively prevents possible secondary melting during packaging and use, and improves the reliability of the assembly process of such products.

[0015] 2. The present application provides a double-sided heat dissipation, large current, high surge Schottky diode and packaging structure and preparation method, the TK3 metal ceramic shell used in the present application is composed of materials with similar linear expansion coefficients such as molybdenum, Al2O3 ceramic and 4J42 Kovar alloy, and a step-by-step assembly and synchronous welding process is adopted; the double-sided heat dissipation, large current, high surge Schottky diode of the present application uses gold-tin solder as the welding material, which reduces the stress generated by different materials during high-temperature sintering, effectively prevents possible secondary melting during packaging and use, and improves the reliability of the assembly process of such products.

[0016] 3. The present application provides a double-sided heat dissipation, large current, high surge Schottky diode and packaging structure and preparation method, the TK3 metal ceramic shell used in the present application is composed of materials with similar linear expansion coefficients such as molybdenum, Al2O3 ceramic and 4J42 Kovar alloy, and a step-by-step assembly and synchronous welding process is adopted; the double-sided heat dissipation, large current, high surge Schottky diode of the present application uses gold-tin solder as the welding material, which reduces the stress generated by different materials during high-temperature sintering, effectively prevents possible secondary melting during packaging and use, and improves the reliability of the assembly process of such products.

[0017] 4. The present application provides a double-sided heat dissipation, large current, high surge Schottky diode and packaging structure and preparation method, the TK3 metal ceramic shell used in the present application is composed of materials with similar linear expansion coefficients such as molybdenum, Al2O3 ceramic and 4J42 Kovar alloy, and a step-by-step assembly and synchronous welding process is adopted; the double-sided heat dissipation, large current, high surge Schottky diode of the present application uses gold-tin solder as the welding material, which reduces the stress generated by different materials during high-temperature sintering, effectively prevents possible secondary melting during packaging and use, and improves the reliability of the assembly process of such products. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a schematic diagram of the packaging structure of the device of the present application; Figure 2 It is a front view of the packaging structure of the device of the present application; Figure 3 It is a top view of the upper electrode of the device of the present application; Figure 4 It is a front view of the upper electrode of the device of the present application; Figure 5 It is the assembly structure of the double-sided heat dissipation, large current, high surge diode used in the device of the present application.

[0019] In the figure: 1, lead-out end; 2, upper electrode, 3, sealing ring, 4, lower electrode, 5, ceramic frame, 6, first gold-tin alloy solder piece, 7, silicon chip, 8, second gold-tin alloy solder piece, 9, TK3 metal ceramic tube seat. DETAILED DESCRIPTION

[0020] The present invention is further described in detail below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] like Figures 1 to 5 As shown, the present invention provides a packaging structure for a Schottky diode with double-sided heat dissipation, high current, and high surge, comprising a TK3 metal-ceramic tube base 9 and an upper electrode 2. The TK3 metal-ceramic tube base 9 includes a sealing ring 3, a lower electrode 4, and a ceramic frame 5. The upper electrode 2 extends between the sealing rings 3. The ceramic frame 5 is wound around the outside of the sealing rings 3 to isolate the upper electrode 2 from the lower electrode 4 and both sides of the sealing ring 3. A chip sintering area is provided between the upper and lower electrodes 2 and 4, and is used to sinter and place a silicon chip. The TK3 metal-ceramic housing used in the present invention is composed of a combination of materials with similar linear expansion coefficients, such as molybdenum, Al2O3 ceramic, and 4J42 Kovar alloy, and is assembled and soldered in a step-by-step process. The double-sided heat dissipation, high current, and high surge Schottky diode of the present invention uses gold-tin solder as the soldering material, reducing the stress generated by the different materials during the high-temperature sintering process, effectively preventing secondary melting that may occur during packaging and use, and improving the reliability of the assembly process for such products. The front and back sides of the chip are directly metallurgically bonded to the upper and lower electrodes via gold-tin solder, effectively improving the device's heat dissipation and overcurrent capabilities. The TK3 metal-ceramic packaged Schottky diode provided by this invention boasts a forward current of up to 200A, a surge current withstand of 2000A (tp = 8.3ms), and a junction-to-case thermal resistance of less than 0.3°C / W.

[0022] In this invention, the stem sintering area (lower electrode) and upper electrode 2 are both made of molybdenum, achieving excellent thermal matching with the silicon chip 7. The sealing ring 3 is made of 4J42 Kovar alloy, and the insulating ceramic frame 5 is made of Al2O3 ceramic, ensuring excellent thermal matching between the various housing components. A molybdenum spacer of approximately 0.25 mm is added to the upper electrode 2 to ensure the overall height after packaging. The inner and outer surfaces of the housing (except for the ceramic portion) are gold-plated to facilitate device packaging and subsequent device soldering. To facilitate user-side soldering, the upper electrode can be equipped with gold-plated copper-invar terminals. The upper electrode 2 can be configured with or without terminals.

[0023] The upper electrode 2 is provided with a lead-out end 1, in order to facilitate the user to paste and use the TK3 profile product, the lead-out end of copper-invar-copper material is welded on the front surface of the upper electrode 2, in order to facilitate the device welding, the outermost layer of the lead-out end is provided with a gold plating layer. In order to facilitate the packaging of the device, the gold-tin soldering sheet is prepared around the upper electrode. In order to realize the good welding of the chip and the upper and lower electrodes, the gold-tin alloy containing sheet is selected as the sintering solder. The upper electrode 2 is prepared with the same gold-tin soldering material as the chip sintering, so that the chip solder does not appear secondary melting during the sealing process, and the position of the chip is ensured not to change.

[0024] In order to realize the isolation of the upper and lower electrodes and the upper and lower sealing rings, the ceramic frame 5 is made of insulating material, and Al2O3 black ceramic is used as the insulating material.

[0025] The outer side of the lower electrode 4 is provided with a gold plating layer, in order to ensure good heat conduction and thermal matching type, the material of the lower electrode 4 is selected as metal molybdenum, and the outermost layer of the metal molybdenum is provided with a gold plating layer for facilitating chip welding.

[0026] In order to realize the air-tight structure of the TK3 shell, the material of the sealing ring 3 adopts 4J42 Kovar alloy, and the thermal expansion coefficient is close to that of molybdenum.

[0027] In order to ensure good heat conduction and thermal matching type, the material of the upper electrode 2 is selected as metal molybdenum, and the outermost layer of the metal molybdenum is provided with a gold plating layer for facilitating chip welding.

[0028] The size of the ceramic frame 5 is 10.92*10.92mm.

[0029] The shape of the lead-out end 1 is a right-angle Z-shaped type, one end of which is connected with the upper electrode 2, the width size of the lead-out end 1 is 5.08mm, and the extension length of the distal end of the lead-out end 1 is 1.65mm.

[0030] The application also provides a double-sided heat dissipation, large current and high surge Schottky diode, which comprises a packaging structure of a double-sided heat dissipation, large current and high surge Schottky diode; the packaging structure is provided with a first gold-tin alloy soldering sheet 6 and a second gold-tin alloy soldering sheet 8 on the inner side, the upper end of the first gold-tin alloy soldering sheet 6 is connected with the upper electrode 2, the lower end of the second gold-tin alloy soldering sheet 8 is connected with the lower electrode 4, and the silicon chip 7 is arranged between the lower end of the first gold-tin alloy soldering sheet 6 and the upper end of the second gold-tin alloy soldering sheet 8. In the application, the TK3 metal ceramic tube seat packaging profile is adopted, on the one hand, good heat conduction can be realized through the shell structure, and on the other hand, the device double-sided heat dissipation can be realized from the packaging angle, so that the heat dissipation capacity of the TK3 profile is greatly improved, and the development and production of the product with a current of more than 150A are facilitated.

[0031] The application further provides a preparation method of the double-sided heat dissipation, large-current and high-surge Schottky diode. Step S1, chip making, a conventional epitaxial planar Schottky process is adopted, a platinum-nickel alloy is used as the barrier metal of the N-type epitaxial wafer, a diffusion protection ring structure of evaporated titanium-nickel-silver composite metal is used on the front surface / back surface of the chip, wherein the outermost layer is silver, used for providing wire bonding or soldering, the middle layer is nickel, used for establishing a barrier layer, and the innermost layer is titanium, used for constructing an adhesion layer; Step S2, chip assembly, the preheated TK3 metal ceramic tube base 9 is placed in the heating area of the atmosphere protection eutectic die bonder, the second gold-tin alloy soldering sheet 8 with the same size as the silicon chip 7 is placed in the chip sintering area, then the Schottky diode silicon chip 7 is placed in the melting area of the second gold-tin alloy soldering sheet 8, and a certain pressure is applied at the same time, so as to fully remove the bubbles possibly generated after the second gold-tin alloy soldering sheet 8 is melted, the TK3 metal ceramic tube base 9 is integrally transferred to the nitrogen protection cooling area, and the cooling is completed; Step S3, sintering inspection, the assembled chip in step S2 is subjected to internal state inspection, if the inspection requirement is met, the next step is continued, and if the inspection requirement is not met, the product not meeting the inspection requirement is removed; Step S4, chip sealing, the first gold-tin alloy soldering sheet 6 with the same size as the upper electrode 2 is placed at the center position of the front surface of the silicon chip 7 which has been sintered with the TK3 metal ceramic tube base 9, the upper electrode 2 of the pre-prepared gold-tin solder is placed in the opening area of the TK3 metal ceramic tube base 9, and the whole assembly is transferred to the atmosphere protection sintering furnace for sealing. In order to prevent the diode chip from being displaced during the sealing process, the chip assembly and device sealing distribution scheme is adopted: since the TK3 metal ceramic tube base 9 is integrally gold-plated, the proportion of gold and tin will change after the gold-tin soldering sheet is sintered, and the original melting point will change, so that the chip will not be displaced during the second sintering (sealing) process. The chip bonding solder, the chip and the upper electrode 2 bonding solder, and the upper electrode 2 and the TK3 metal ceramic tube base 9 sealing pre-prepared solder are all gold-tin alloys: the TK3 metal ceramic tube base 9 is provided with a gold-plated layer on the inner and outer surfaces, after the gold-tin solder is used to sinter the chip, the proportion of gold and tin in the gold-tin solder changes, and when the upper electrode is sintered and sealed again, the chip will not be displaced due to the melting of the solder, and meanwhile, the user end will not cause the secondary melting of the solder in the device during the device assembly.

[0032] The double-sided heat dissipation, large-current, high-surge Schottky diode packaged by TK3 metal ceramic and the manufacturing method thereof can better meet the miniaturization, light weight, integration development and power trend of high-end weapon equipment systems in the fields of aerospace, aviation, weapons and ships, and can realize the localization of large-current silicon Schottky diode devices, so as to improve the localization rate of the whole machine components and avoid the adverse effects of the import device embargo on the progress of the whole machine.

[0033] Of course, the above-mentioned embodiments are not a limitation of the present application, and the present application is not limited to the above examples. Changes, modifications, additions or substitutions made by those skilled in the art within the scope of the present application should also be within the scope of the present application.

Claims

1. A package structure for a Schottky diode with double-sided heat dissipation, high current, and high surge, characterized by: include: A TK3 metal ceramic tube base (9) and an upper electrode (2), wherein the TK3 metal ceramic tube base (9) comprises a sealing ring (3), a lower electrode (4) and a ceramic frame (5), wherein the upper electrode (2) extends between the sealing rings (3), and the ceramic frame (5) is wound around the outside of the sealing ring (3) and is used to isolate the upper electrode (2) from the lower electrode (4) and both sides of the sealing ring (3), and a chip sintering area is provided between the upper electrode (2) and the lower electrode (4), and the chip sintering area is used to sinter and place a silicon chip.

2. The packaging structure of a Schottky diode with double-sided heat dissipation, high current, and high surge according to claim 1, characterized in that: The upper electrode (2) is provided with a lead-out terminal (1), the outer side of the lead-out terminal (1) is provided with a gold-plated layer, and the material of the lead-out terminal (1) is copper-invar-copper.

3. The packaging structure of a Schottky diode with double-sided heat dissipation, high current, and high surge according to claim 1, characterized in that: The ceramic frame (5) is an insulating material, and the material of the ceramic frame (5) is Al2O3 ceramic.

4. The packaging structure of a Schottky diode with double-sided heat dissipation, high current, and high surge according to claim 1, characterized in that: A gold-plated layer is provided on the outer side of the lower electrode (4), and the material of the lower electrode (4) is metallic molybdenum.

5. The packaging structure of a Schottky diode with double-sided heat dissipation, high current, and high surge according to claim 1, characterized in that: The sealing ring (3) is made of 4J42 Kovar alloy material.

6. The packaging structure of a Schottky diode with double-sided heat dissipation, high current, and high surge according to claim 1, characterized in that: A gold-plated layer is provided on the outer side of the upper electrode (2), and the material of the upper electrode (2) is metallic molybdenum.

7. The packaging structure of a Schottky diode with double-sided heat dissipation, high current, and high surge according to claim 3, characterized in that: The size of the ceramic frame (5) is 10.92×10.92 mm.

8. The packaging structure of a Schottky diode with double-sided heat dissipation, high current, and high surge according to claim 2, characterized in that: The lead-out end (1) is in a right-angled Z-shape, one end of which is connected to the upper electrode (2). The width of the lead-out end (1) is 5.08 mm, and the distal extension length of the lead-out end (1) is 1.65 mm.

9. A Schottky diode with double-sided heat dissipation, high current, and high surge, characterized by: include: A packaging structure for a Schottky diode with double-sided heat dissipation, high current, and high surge as described in any one of claims 1 to 8; a first gold-tin alloy solder piece (6) and a second gold-tin alloy solder piece (8) are provided on the inner side of the packaging structure, the upper end of the first gold-tin alloy solder piece (6) is connected to the upper electrode (2), the lower end of the second gold-tin alloy solder piece (8) is connected to the lower electrode (4), and a silicon chip (7) is provided between the lower end of the first gold-tin alloy solder piece (6) and the upper end of the second gold-tin alloy solder piece (8).

10. A method for preparing a Schottky diode with double-sided heat dissipation, high current, and high surge, characterized by: The following steps are involved: Step S1: Chip fabrication using a conventional epitaxial planar Schottky process. N-type epitaxial wafers use platinum-nickel alloy as the barrier metal. The front and back sides of the chip use a diffusion guard ring structure of evaporated titanium-nickel-silver composite metal. The outermost layer is silver for wire bonding or welding, the middle layer is nickel for establishing a barrier layer, and the innermost layer is titanium for component adhesion. Step S2, chip assembly, placing the preheated TK3 metal ceramic tube seat (9) in the heating zone of the atmosphere protected eutectic bonding machine, placing the second gold-tin alloy solder sheet (8) of the same size as the silicon chip (7) in the chip sintering zone, and then placing the Schottky diode silicon chip (7) in the area where the second gold-tin alloy solder sheet (8) is melted, while applying a certain pressure to fully eliminate bubbles that may be generated after the second gold-tin alloy solder sheet (8) is melted, and the TK3 metal ceramic tube seat (9) is transferred as a whole to the cooling zone protected by nitrogen to complete cooling; Step S3, sintering inspection, performs internal inspection on the assembled chip in step S2. If it meets the inspection requirements, proceed to the next step; if it does not meet the inspection requirements, the product that does not meet the inspection requirements is rejected; Step S4, chip sealing, placing a first gold-tin alloy solder sheet (6) of the same size as the upper electrode (2) on the front center of the silicon chip (7) that has been sintered with the TK3 metal ceramic tube base (9), placing the upper electrode (2) made of prefabricated gold-tin solder in the opening area of ​​the TK3 metal ceramic tube base (9), and transferring the assembled whole to an atmosphere-protected sintering furnace for sealing.

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