A sintering device and a sintering method for semiconductor devices

Abstract

The present invention relates to the technical field of semiconductor device processing equipment, and particularly relates to a sintering device and a sintering method for semiconductor devices. A sintering device for semiconductor devices includes: a workbench, on which a driving structure and a heating structure are provided; a pressing structure, which is arranged on the workbench and corresponds to the driving structure. The pressing structure includes a clamping mechanism and a plurality of force applying mechanisms arranged on the clamping mechanism. The plurality of force applying mechanisms correspond to a plurality of semiconductor devices arranged on the workbench one by one. The force applying mechanism includes a pressing head and a pressure balancing component connected to the pressing head. The pressure balancing component includes a first biasing member that deforms in the force application direction when the pressing head applies force. The present invention provides a sintering device and a sintering method for semiconductor devices, which have stable pressure during operation and reduce the damage rate of semiconductor devices.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor device processing equipment, and particularly relates to a sintering device and a sintering method for semiconductor devices. Background Art

[0002] In recent years, with the rapid development of power, high-speed rail, electric vehicles, etc., the demand for high-power semiconductor devices has increased rapidly. High-power semiconductor devices have high power density and large heat generation, and they have very high requirements for heat dissipation themselves. The thermal conductivity of the welding materials used for packaging high-power semiconductor devices has a great influence on the heat dissipation ability of the devices. Therefore, ultra-high thermal conductivity welding materials have become an important direction for research and development. Nano-silver paste solder is the focus of development in the industry in recent years. Its thermal conductivity is 3-5 times that of traditional solders such as solder and SAC, and it is considered an ideal alternative.

[0003] The solder used in traditional semiconductor packaging welding does not require pressure, only heating. The equipment used for packaging welding is mainly a reflow soldering furnace, which adjusts the temperature in multiple temperature zones and controls the temperature by means of an air convection heating cycle to ensure uniform temperature within a certain heating time. Moreover, the processes and equipment used in traditional semiconductor packaging welding can only meet the process requirements under non-pressure conditions, and the equipment is huge. However, nano-silver paste requires welding by heating and pressurizing methods. In semiconductor packaging welding that requires simultaneous heating and pressurization, traditional processes and equipment cannot be realized.

[0004] For this reason, the prior art has proposed a hot press sintering machine. A servo motor installed on the top of the machine drives the reducer and the lead screw to rotate, driving the nut pair, so that the pressure sensor and the upper heating plate installed at the bottom of the guide rod move up and down under the guidance of the guide rod, and the pressure to be applied to the processed device can be set in segments according to process requirements. Although this device realizes the control of the pressure during sintering, the pressure value is not stable. Especially for semiconductor chips with a small processing area, when the pressure is unstable, the chip may be burned out or the gate may be damaged, affecting the quality of the final product. Summary of the Invention

[0005] Therefore, the technical problem to be solved by the present invention is to overcome the defect that the pressure of the hot press sintering machine in the prior art is unstable during operation and easily damages semiconductor devices, so as to provide a sintering device and a sintering method for semiconductor devices with stable pressure during operation and reduced damage rate of semiconductor devices.

[0006] To solve the above technical problem, the present invention provides a sintering device for semiconductor devices, including:

[0007] A workbench, on which a driving structure and a heating structure are provided;

[0008] The pressing structure is provided on the workbench and is correspondingly arranged with the driving structure. The pressing structure includes a clamping mechanism and a plurality of force applying mechanisms provided on the clamping mechanism. The plurality of force applying mechanisms correspond to a plurality of semiconductor devices provided on the workbench one by one. The force applying mechanism includes a pressing head and a pressure balancing component connected to the pressing head. The pressure balancing component includes a first biasing member that deforms along the force application direction when the pressing head applies force.

[0009] Optionally, the pressure balancing component further includes a first fixing member and a second fixing member provided at both ends of the first biasing member, and a first guide rod provided between the first fixing member and the second fixing member. The first biasing member is sleeved on the first guide rod.

[0010] Optionally, it further includes a second biasing member provided between the second fixing member and the pressing head.

[0011] Optionally, a first pressure sensor and a first temperature sensor are further provided between the second biasing member and the pressing head.

[0012] Optionally, the pressing structure further includes a sample stage correspondingly arranged with the clamping mechanism. Through holes are provided on the sample stage.

[0013] Optionally, an adsorption layer is further provided in the sample stage. The adsorption layer is arranged in communication with the through holes of the sample stage.

[0014] Optionally, a second pressure sensor and a second temperature sensor are further provided in the sample stage.

[0015] Optionally, the pressing structure further includes a bracket. The sample stage is provided on the bracket. The clamping mechanism is slidably connected to the bracket through a second guide rod provided on the bracket.

[0016] Optionally, the heating structure includes a first heating structure and a second heating structure respectively provided on opposite sides of the pressing structure.

[0017] A sintering method for semiconductor devices is also provided, including the following steps:

[0018] Place a plurality of semiconductor devices on the workbench at intervals. The driving structure drives the clamping mechanism and the plurality of force applying mechanisms to move towards the semiconductor devices, so as to apply a pressing force to the semiconductor devices through the first biasing member. The temperature during pressing is 250 - 300 °C, and the pressing time is 5 - 20 min.

[0019] The technical solution of the present invention has the following advantages:

[0020] 1. The sintering equipment for semiconductor devices provided by the present invention places multiple semiconductor devices at predetermined positions on a workbench in sequence. A driving structure drives a clamping mechanism to move towards the semiconductor devices, so as to drive multiple force-applying mechanisms to apply a pressing force to the corresponding semiconductor devices. During the pressing process, due to the setting of a first biasing member connected to the pressing head, the first biasing member deforms during the pressing process, making the pressing force exerted by the pressing head on the semiconductor devices always in dynamic balance, that is, the pressure received at each place is equal in magnitude, thereby reducing the damage of the semiconductor devices caused by uneven force and improving the product quality; and the multiple force-applying mechanisms are arranged in one-to-one correspondence with the multiple semiconductor devices, applying pressure individually, and the pressure is more stable.

[0021] 2. In the sintering equipment for semiconductor devices provided by the present invention, the setting of the first guide rod between the first fixing member and the second fixing member provides guidance for the movement of the first biasing member, preventing the first biasing member from having too large a displacement after being stressed, resulting in uneven pressing force on the semiconductor devices.

[0022] 3. In the sintering equipment for semiconductor devices provided by the present invention, the setting of the second biasing member between the second fixing member and the pressing head further improves the force uniformity of the semiconductor devices and ensures the product quality.

[0023] 4. In the sintering equipment for semiconductor devices provided by the present invention, the setting of the through holes and the adsorption layer on the sample table can better fix the semiconductor devices, preventing them from shifting during the sintering process and affecting the force uniformity. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the drawings required for use in the description of the specific embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0025] Figure 1 is a schematic diagram of the sintering equipment for semiconductor devices provided by the present invention;

[0026] Figure 2 is Figure 1 the front view after removing the cover and the cooling box;

[0027] Figure 3 is Figure 2 the schematic diagram of the pressing structure in

[0028] Figure 4 the schematic diagram of the clamping mechanism and the force-applying mechanism;

[0029] Figure 5Schematic diagram of the pressure equalizing component;

[0030] Figure 6 Schematic diagram of the sample stage;

[0031] Figure 7 For Figure 6 Top view of;

[0032] Figure 8 Schematic diagram of the adsorption layer.

[0033] Explanation of reference numerals:

[0034] 1. Semiconductor device; 2. Workbench; 3. Cover body; 4. Human-machine operation interface; 5. Vacuum pump interface; 6. High-purity nitrogen interface; 7. Formic acid interface; 8. Vacuum interface; 9. Cooling box; 10. Servo motor; 11. Reducer; 12. Lead screw; 13. First heating structure; 14. Nut pair; 15. Guide rod; 16. Mounting rack; 17. Second heating structure; 18. Clamping mechanism; 19. Base; 20. Top plate; 21. Second guide rod; 22. Pressure equalizing component; 23. Second biasing member; 24. First pressure sensor; 25. First temperature sensor; 26. Pressure head; 27. First biasing member; 28. First fixing member; 29. Second fixing member; 30. First guide rod; 31. Sample stage; 32. Adsorption layer; 33. Second temperature sensor; 34. Second pressure sensor. Detailed implementation manners

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments of the present invention belong to the scope of protection of the present invention.

[0036] In addition, the technical features involved in different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0037] As Figures 1 to 8 shown, a specific implementation manner of a sintering device for semiconductor devices, the semiconductor device 1 is a high-power press-pack IGBT module with nano-silver paste sintered on its surface, the thickness of the nano-silver paste is 0.5 - 1 μm, and it includes a workbench 2 and a driving structure, a heating structure and a pressing structure provided on the workbench 2.

[0038] A cover 3 is provided on the workbench 2, and a man-machine operation interface 4 is provided on the cover 3. The cover 3 can form a sealed space with the workbench 2, and a vacuum pump interface 5, a high-purity nitrogen interface 6, a formic acid interface 7, and a vacuum interface 8 are reserved at corresponding positions of the cover 3 to meet the requirements of the sintering process. A driving structure, a heating structure, and a pressing structure are placed inside the sealed space. In addition, a cooling box 9 can be provided on one side of the cover 3 to enable the equipment to have a cooling function and increase production capacity.

[0039] The driving structure includes a servo motor 10, a speed reducer 11, a lead screw 12, and a first heating structure 13 arranged in sequence. The lead screw 12 is connected to the speed reducer 11 through a nut pair 14. The driving structure is slidably connected to a mounting frame 16 provided on the workbench 2 through a guide rod 15. A second heating structure 17 corresponding to the first heating structure 13 is provided in the center of the mounting frame 16. Both the first heating structure 13 and the second heating structure 17 are heating plates.

[0040] The pressing structure is arranged between the first heating structure 13 and the second heating structure 17 of the workbench 2 and is correspondingly arranged with the driving structure. The pressing structure includes a bracket, a clamping mechanism 18 provided on the bracket, and a plurality of force applying mechanisms provided on the clamping mechanism 18. The bracket includes a base 19, a top plate 20 arranged oppositely, and a second guide rod 21 for connecting the base 19 and the top plate 20. The clamping mechanism 18 is fixed on the top plate 20.

[0041] The plurality of force applying mechanisms correspond to a plurality of semiconductor devices 1 provided on the workbench 2. The force applying mechanism includes a pressure equalizing component 22, a second biasing member 23, a first pressure sensor 24, a first temperature sensor 25, and a pressing head 26 arranged in sequence from top to bottom. The pressure equalizing component includes a first biasing member 27 that deforms along the force application direction when the pressing head 26 applies force, first fixing members 28 and second fixing members 29 provided at both ends of the first biasing member 27, and a first guide rod 30 provided between the first fixing member 28 and the second fixing member 29. The first biasing member 27 is sleeved on the first guide rod 30. Both ends of the first guide rod 30 are fixedly connected to the centers of the first fixing member 28 and the second fixing member 29. The first biasing member 27 is a disc spring and has a large contact area with the first fixing member 28 and the second fixing member 29. The second biasing member 23 is an elastic body such as a rubber block. The pressing head 26 is made of a rigid material and can be customized according to sample requirements, and the spacing is adjusted according to the sample spacing.

[0042] A sample stage 31 corresponding to the clamping mechanism 18 is provided on the base 19 of the bracket. The sample stage 31 is a Teflon film, and through holes are provided on the sample stage 31, and the size of the through holes matches the sample. An adsorption layer 32, a second temperature sensor 33, and a second pressure sensor 34 are sequentially arranged below the sample stage 31. The adsorption layer 32 has a porous structure, and the adsorption layer 32 is communicated with the through holes of the sample stage 31.

[0043] A sintering method for semiconductor devices, comprising the following steps:

[0044] Place multiple semiconductor devices on the sample stage at intervals, evacuate the sample stage through a vacuum pump connected to the through holes of the sample stage to adsorb the semiconductor devices on the sample stage, and introduce nitrogen and formic acid through the high-purity nitrogen interface and the formic acid interface. The servo motor drives the lead screw to rotate through a speed reducer, and under the action of the guide rod, the first heating plate installed at the bottom end of the guide rod moves towards the second heating plate. When the first heating plate contacts the top plate of the bracket, the top plate drives the clamping mechanism and multiple force-applying mechanisms to move towards the semiconductor devices along the second guide rod until the indenter contacts the semiconductor devices and continues to move downward. During the downward movement, the first biasing member and the second biasing member adjust the pressing force applied to the semiconductor devices through deformation, so that the pressing force received by each semiconductor device is equal in magnitude and evenly distributed. First, control the pre-sintering temperature to be 130 - 170 °C and the time to be 50 - 100 s, and then control the temperature during pressing to be 250 - 300 °C and the pressing time to be 5 - 20 min. During the pre-sintering and pressing processes, the pressing force and temperature changes are monitored in real time through the first pressure sensor, the second pressure sensor, the first temperature sensor, and the second temperature sensor, and relevant adjustments are made in a timely manner to ensure that the semiconductor devices are evenly stressed and heated throughout the processing process.

[0045] As an alternative implementation, both ends of the first biasing member are respectively fixed to the clamping mechanism and the indenter.

[0046] As an alternative implementation, the first biasing member and the second biasing member can also be compression springs.

[0047] As an alternative implementation, the sintering material can be a metal, such as gold, silver, etc., and can also be a nanomaterial, a nano / micron composite material, etc. It can be in a film structure or a paste structure, and can be single-sided sintering or double-sided sintering, and can be one-time sintering or two-time sintering.

[0048] Obviously, the above embodiments are merely examples given for clear illustration and are not limitations on the implementation manners. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A sintering device for semiconductor devices, characterized in that, Including: A workbench (2), on which a driving structure and a heating structure are provided; A pressing structure, which is arranged on the workbench (2) and corresponds to the driving structure. The pressing structure includes a clamping mechanism (18) and a plurality of force applying mechanisms arranged on the clamping mechanism (18). The plurality of force applying mechanisms correspond to a plurality of semiconductor devices (1) arranged on the workbench (2) one by one. The force applying mechanism includes a pressing head (26) and a pressure balancing component connected to the pressing head (26). The pressure balancing component includes a first biasing member (27) that deforms along the force application direction when the pressing head (26) applies force; The pressure balancing component further includes a first fixing member (28) and a second fixing member (29) arranged at both ends of the first biasing member (27), and a first guide rod (30) arranged between the first fixing member (28) and the second fixing member (29). The first biasing member (27) is sleeved on the first guide rod (30); It further includes a second biasing member (23) arranged between the second fixing member (29) and the pressing head (26); A first pressure sensor (24) and a first temperature sensor (25) are further arranged between the second biasing member (23) and the pressing head (26); The pressing structure further includes a sample stage (31) corresponding to the clamping mechanism (18). The sample stage (31) is provided with a through hole; a second pressure sensor (34) and a second temperature sensor (33) are further arranged in the sample stage (31). The first biasing member is a disc spring, and the second biasing member is a rubber block.

2. The sintering device for semiconductor devices according to claim 1, characterized in that, An adsorption layer (32) is further arranged in the sample stage (31), and the adsorption layer (32) is arranged in communication with the through hole of the sample stage (31).

3. The sintering device for semiconductor devices according to claim 1, characterized in that, The pressing structure further includes a bracket. The sample stage (31) is arranged on the bracket, and the clamping mechanism (18) is slidably connected to the bracket through a second guide rod (21) arranged on the bracket.

4. The sintering device for semiconductor devices according to any one of claims 1 - 3, characterized in that, The heating structure includes a first heating structure (13) and a second heating structure (17) respectively arranged on opposite sides of the pressing structure.

5. A sintering method for semiconductor devices, characterized in that, Sintering is carried out by using the sintering equipment according to any one of claims 1-4, including the following steps: Placing a plurality of semiconductor devices (1) on the workbench (2) at intervals, and the driving structure drives the clamping mechanism (18) and a plurality of force applying mechanisms to move towards the semiconductor devices (1) to apply a pressing force to the semiconductor devices (1) through the first biasing member (27). The temperature during pressing is 250-300 °C, and the pressing time is 5-20 min.

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