Activated formic acid gas protection device special for copper sintering of power device

Abstract

The utility model provides a special activated formic acid gas protection device for copper sintering of a power device, which comprises an upper cover assembly and a base assembly, the upper cover assembly and the base assembly are enclosed to form a sintering chamber, the upper cover assembly comprises an upper cover and a first sealing ring, and the base assembly comprises a base and a second sealing ring; a first sealing ring positioning groove and a second sealing ring positioning groove are formed in the end faces of the opposite sides of the upper cover and the base respectively, the first sealing ring and the second sealing ring are arranged in the first sealing ring positioning groove and the second sealing ring positioning groove respectively, and a first flange is arranged on the side wall of the first sealing ring positioning groove. A second flange is arranged on the side wall of the second sealing ring positioning groove; after the upper cover assembly and the base assembly are closed in a covering mode, the first flange is embedded into the second sealing ring positioning groove and abuts against the second sealing ring in a sealed mode, the second flange is embedded into the first sealing ring positioning groove and abuts against the first sealing ring in a sealed mode, and by means of the interlocking sealing scheme, the sealing performance of the device can be improved, and environmental pollution caused by waste gas leakage is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of copper sintering and packaging equipment for power semiconductor devices, in particular to an activated formic acid gas protection device dedicated for copper sintering of power devices. Background Art

[0002] With the increasing demand for miniaturization, integration, and energy efficiency in power devices, third-generation wide-bandgap semiconductors, represented by silicon carbide (SiC) and gallium nitride (GaN), have seen significant development and application. Third-generation wide-bandgap semiconductors have higher operating junction temperatures, maintaining excellent performance above 350°C. However, as power device performance improves, their packaging technology faces unprecedented challenges. Traditional Sn-based brazing processes, such as those used in soldering, are unable to meet the stringent heat dissipation, electrical conductivity, and mechanical performance requirements of power devices under the complex operating conditions of low-temperature packaging and high-temperature operation. Therefore, the industry urgently needs to develop new packaging technologies to meet the demands of the next generation of semiconductor devices.

[0003] In this context, new packaging methods represented by sintered silver / sintered copper processes have emerged and gradually become the mainstream technology for power device packaging. In particular, the copper sintering process, with its excellent economy and high sintering strength, is generally considered to be an important direction for future product development and application. However, in actual process applications, sintered copper technology also faces some problems, the most critical of which is the anti-oxidation treatment of devices during the sintering process. Generally, activated formic acid gas is introduced into the sintering chamber for anti-oxidation treatment to ensure sintering quality and device performance. Although existing protection measures can alleviate the oxidation problem to a certain extent, if the formic acid waste gas in the sintering chamber leaks during the sintering process or the formic acid waste gas is not thoroughly treated, it will cause environmental pollution and harm to personnel health.

[0004] Therefore, developing a new type of protection device that can effectively prevent the oxidation of copper during the sintering process of power devices and safely and efficiently treat the formic acid waste gas generated during the sintering process has become a technical problem that needs to be solved urgently. Utility Model Content

[0005] The utility model provides a special activated formic acid gas protection device for copper sintering of power devices, which is used to solve the problems of environmental pollution and damage to personnel health caused by leakage of formic acid waste gas or incomplete treatment of formic acid waste gas during the sintering process of power devices.

[0006] The utility model provides a special activated formic acid gas protection device for copper sintering of power devices, comprising:

[0007] An upper cover assembly, comprising an upper cover and a first sealing ring;

[0008] A base assembly is arranged opposite to the upper cover assembly, and includes a base and a second sealing ring. The upper cover assembly and the base assembly together form a sintering chamber;

[0009] A first sealing ring positioning groove and a second sealing ring positioning groove are respectively provided on end surfaces on opposite sides of the upper cover and the base; a first flange protruding toward one side of the sintering chamber is formed on a side wall of the first sealing ring positioning groove close to the sintering chamber; a second flange protruding away from the sintering chamber is formed on a side wall of the second sealing ring positioning groove away from the sintering chamber;

[0010] The first sealing ring is arranged in the first sealing ring positioning groove, and the second sealing ring is arranged in the second sealing ring positioning groove. When the upper cover assembly and the base assembly are in the covered state, the first flange is embedded in the second sealing ring positioning groove and is in sealing contact with the second sealing ring, and the second flange is embedded in the first sealing ring positioning groove and is in sealing contact with the first sealing ring.

[0011] According to the activated formic acid gas protection device for copper sintering of power devices provided by the present invention, the first sealing ring positioning groove is recessed along the height direction of the upper cover, and the height of the side wall of the first sealing ring positioning groove close to the sintering chamber is greater than the height of the side wall away from the sintering chamber;

[0012] The second sealing ring positioning groove is recessed along the height direction of the base, and the height of the side wall of the second sealing ring positioning groove close to the sintering chamber is smaller than the height of the side wall away from the sintering chamber.

[0013] According to the activated formic acid gas protection device for copper sintering of power devices provided by the present invention, the side wall height of the first sealing ring positioning groove close to the sintering chamber is equal to the side wall height of the second sealing ring positioning groove away from the sintering chamber.

[0014] According to the activated formic acid gas protection device specially used for copper sintering of power devices provided by the utility model, when the upper cover assembly and the base assembly are in the covered state, the end face of the upper cover corresponding to the first sealing ring positioning groove away from the sintering chamber is tightly fitted with the end face of the base corresponding to the second sealing ring positioning groove away from the sintering chamber.

[0015] According to the activated formic acid gas protection device dedicated to copper sintering of power devices provided by the utility model, the first sealing ring and the second sealing ring are both rubber sealing rings.

[0016] According to the activated formic acid gas protection device for copper sintering of power devices provided by the present invention, the upper cover assembly further includes a pressure applying and heating mechanism and a third sealing ring. A through hole is provided on the top of the upper cover, and the pressure applying and heating mechanism is passed through the through hole on the upper cover.

[0017] Wherein, a third sealing ring positioning groove is provided on the inner wall of the through hole, and the third sealing ring is arranged in the third sealing ring positioning groove and is in sealing contact with the side wall of the pressure applying and heating mechanism.

[0018] According to the activated formic acid gas protection device dedicated to copper sintering of power devices provided by the utility model, the third sealing ring is a rubber sealing ring.

[0019] According to the activated formic acid gas protection device for copper sintering of power devices provided by the utility model, the pressure applying and heating mechanism includes a pressure applying mechanism and a first sintering heating mechanism, and the first sintering heating mechanism is arranged at one end of the pressure applying mechanism close to the base;

[0020] A second sintering heating mechanism corresponding to the first sintering heating mechanism is provided in the base. The first sintering heating mechanism and the second sintering heating mechanism are used to heat the power device from the top and bottom of the power device respectively.

[0021] According to the activated formic acid gas protection device for copper sintering of power devices provided by the present invention, a gas inlet is provided on the side wall of the upper cover, and the gas inlet is connected to an external formic acid activated gas device for introducing activated formic acid gas into the sintering chamber;

[0022] A negative pressure vacuum port and a waste gas exhaust port are provided on the side wall of the base. The negative pressure vacuum port is connected to an external vacuum pump and is used to evacuate the sintering chamber to form a negative pressure; the waste gas exhaust port is connected to an external formic acid waste gas exhaust system and is used to exhaust the formic acid waste gas in the sintering chamber.

[0023] According to the activated formic acid gas protection device dedicated to copper sintering of power devices provided by the utility model, the cross-sectional shapes of the first flange and the second flange are both semicircular.

[0024] The above technical solution of the utility model has the following beneficial effects:

[0025] The utility model discloses a special activated formic acid gas protection device for copper sintering of power devices. The device comprises a first sealing ring positioning groove and a second sealing ring positioning groove respectively provided on the end surfaces on opposite sides of the upper cover and the base, the first sealing ring and the second sealing ring being respectively placed in the first sealing ring positioning groove and the second sealing ring positioning groove, and a first flange protruding toward the side of the sintering chamber is formed on the side wall of the first sealing ring positioning groove close to the sintering chamber, and a second flange protruding away from the side of the sintering chamber is formed on the side wall of the second sealing ring positioning groove away from the sintering chamber. When the upper cover assembly and the base assembly are covered, the first flange can be embedded in the second sealing ring positioning groove and sealed against the second sealing ring, and the second flange can be embedded in the first sealing ring positioning groove and sealed against the first sealing ring. This interlocking sealing form can effectively improve the sealing performance of the device, solve the problems of environmental pollution caused by leakage of formic acid waste gas during the sintering process of the power device or incomplete treatment of formic acid waste gas, and damage to personnel health, and ensure the stability of the gas pressure inside the chamber during the copper sintering process of the power device, thereby saving the amount of activated formic acid gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0027] Figure 1 This is a schematic diagram of the assembly of a dedicated activated formic acid gas protection device for copper sintering of power devices provided by an embodiment of the present invention;

[0028] Figure 2 for Figure 1 Schematic diagram of the explosion of the activated formic acid gas protection device shown in;

[0029] Figure 3 This is a cross-sectional view of a dedicated activated formic acid gas protection device for copper sintering of power devices provided by an embodiment of the present invention;

[0030] Figure 4 This is a second cross-sectional view of the activated formic acid gas protection device for copper sintering of power devices provided by an embodiment of the present invention;

[0031] Figure 5 The present invention provides a process flow chart for performing a copper sintering process using the activated formic acid gas protection device specifically designed for copper sintering of power devices provided by an embodiment of the present invention.

[0032] Reference numerals:

[0033] 1. Upper cover; 2. First sealing ring; 3. Base; 4. Second sealing ring; 5. Pressure applying and heating mechanism; 6. Third sealing ring; 101. First sealing ring positioning groove; 102. First flange; 103. Gas inlet; 104. Third sealing ring positioning groove; 301. Second sealing ring positioning groove; 302. Second flange; 303. Negative pressure vacuum port; 304. Waste gas outlet; 305. Second sintering and heating mechanism; 501. Pressure applying mechanism; 502. First sintering and heating mechanism. DETAILED DESCRIPTION

[0034] To make the purpose, technical solutions, and advantages of the present invention more clear, the following will be combined with the accompanying drawings to clearly and completely describe the technical solutions of the present invention. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0035] See also Figure 1 and Figure 2 The present invention provides a dedicated activated formic acid gas protection device for copper sintering of power devices. The device comprises an upper cover assembly and a base assembly positioned relative to each other, forming a sintering chamber in which the power device can be placed for copper sintering.

[0036] Among them, the upper cover assembly includes an upper cover 1 and a first sealing ring 2, and the base assembly includes a base 3 and a second sealing ring 4. The upper cover 1 and the base 3 are both hollow structures, and the upper cover 1 and the base 3 are covered to form a sintering chamber.

[0037] A first sealing ring positioning groove 101 and a second sealing ring positioning groove 301 are respectively provided on the end surfaces on opposite sides of the upper cover 1 and the base 3. The first sealing ring positioning groove 101 is recessed along the height direction of the upper cover 1 and surrounds the lower end surface of the upper cover 1. The second sealing ring positioning groove 301 is recessed along the height direction of the base 3 and surrounds the upper end surface of the base 3. A first flange 102 protruding toward the sintering chamber is formed on the sidewall of the first sealing ring positioning groove 101 near the sintering chamber, and a second flange 302 protruding away from the sintering chamber is formed on the sidewall of the second sealing ring positioning groove 301 away from the sintering chamber.

[0038] The first sealing ring 2 is arranged in the first sealing ring positioning groove 101, and the second sealing ring 4 is arranged in the second sealing ring positioning groove 301. When the upper cover assembly and the base assembly are in the covered state, the first flange 102 is embedded in the second sealing ring positioning groove 301 and is sealed against the second sealing ring 4, and the second flange 302 is embedded in the first sealing ring positioning groove 101 and is sealed against the first sealing ring 2.

[0039] The utility model provides a first flange 102 protruding toward the side of the sintering chamber on the side wall of the first sealing ring positioning groove 101 close to the sintering chamber, and provides a second flange 302 protruding away from the side of the sintering chamber on the side wall of the second sealing ring positioning groove 301 away from the sintering chamber, and places the first sealing ring 2 and the second sealing ring 4 in the first sealing ring positioning groove 101 and the second sealing ring positioning groove 301 respectively. When the upper cover assembly and the base assembly are covered, the first flange 102 can be embedded in the second sealing ring positioning groove 301, and the first flange 102 compresses the second sealing ring 4 to form a compression fit with the second sealing ring 4 to achieve the effect of sealing the sintering chamber; at the same time, the second flange 302 can be embedded in the first sealing ring positioning groove 101, and the second flange 302 compresses the first sealing ring 2 to form a compression fit with the first sealing ring 2 to achieve the effect of sealing the sintering chamber. In this way, an interlocking sealing structure can be formed between the upper cover assembly and the base assembly, effectively improving the sealing performance of the device, solving the problem of environmental pollution caused by leakage of formic acid waste gas during the sintering process of power devices or incomplete treatment of formic acid waste gas, as well as damage to personnel health, and ensuring the stability of the gas pressure inside the chamber during the copper sintering process of power devices, saving the amount of activated formic acid gas.

[0040] The cross-sectional shapes of the first flange 102 and the second flange 302 are both semicircular, but are not limited thereto. Any shape is acceptable as long as it facilitates compression of the first sealing ring 2 and the second sealing ring 4 and provides good sealing performance.

[0041] See also Figure 3 The side wall of the upper cover 1 is provided with a gas inlet 103, which is connected to an external formic acid activation gas device and is used to introduce activated formic acid gas into the sintering chamber. The side wall of the base 3 is provided with a negative pressure vacuum port 303 and an exhaust gas outlet 304. The negative pressure vacuum port 303 is connected to an external vacuum pump to remove air from the sintering chamber before the device copper is sintered, thereby creating a negative pressure in the sintering chamber. The exhaust gas outlet 304 is connected to an external formic acid exhaust system to exhaust the formic acid exhaust gas in the sintering chamber after the device copper is sintered to prevent environmental pollution.

[0042] Please continue reading Figure 1 and Figure 2The side wall height of the first sealing ring positioning groove 101 on the side close to the sintering chamber is greater than the side wall height away from the sintering chamber, and the first flange 102 is formed at the end of the side wall of the first sealing ring positioning groove 101 on the side close to the sintering chamber; and the side wall height of the second sealing ring positioning groove 301 on the side close to the sintering chamber is less than the side wall height away from the sintering chamber, and the second flange 302 is formed at the end of the side wall of the second sealing ring positioning groove 301 on the side away from the sintering chamber. This design method facilitates the first flange 102 to be embedded in the second sealing ring positioning groove 301, and the second flange 302 to be embedded in the first sealing ring positioning groove 101 after the upper cover assembly and the base assembly are closed.

[0043] Furthermore, the side wall height of the first sealing ring positioning groove 101 close to the sintering chamber side is equal to the side wall height of the second sealing ring positioning groove 301 away from the sintering chamber side. This can ensure that after the upper cover assembly and the base assembly are covered, the first flange 102 can effectively compress and fit with the second sealing ring 4 to form a first sealing structure, and the second flange 302 can effectively compress and fit with the first sealing ring 2 to form a second sealing structure.

[0044] When the upper cover assembly and the base assembly are closed, the end surface of the upper cover 1 corresponding to the first sealing ring positioning groove 101, which is away from the sintering chamber, and the end surface of the base 3 corresponding to the second sealing ring positioning groove 301, which is away from the sintering chamber, are in close contact. In this way, on the basis of the double seal formed by the first and second sealing structures, the tight fit between the outer peripheries of the upper cover 1 and the base 3 further enhances the sealing performance of the device.

[0045] See also Figures 1-4 The upper cover assembly also includes a pressure-applying and heating mechanism 5 and a third sealing ring 6. The top of the upper cover 1 is provided with a through-hole, through which the pressure-applying and heating mechanism 5 is installed. The pressure-applying and heating mechanism 5 is configured to move along the centerline of the upper cover 1 to compress and heat the power devices. A third sealing ring positioning groove 104 is provided on the inner wall of the through-hole. The third sealing ring 6 is positioned within this groove and sealably abuts against the sidewall of the pressure-applying and heating mechanism 5, thereby sealing the top of the upper cover 1.

[0046] Furthermore, the pressure-applying and heating mechanism 5 includes a pressure-applying mechanism 501 and a first sintering heating mechanism 502. The first sintering heating mechanism 502 is disposed at one end of the pressure-applying mechanism 501 near the base 3. A second sintering heating mechanism 305 is disposed within the base 3, corresponding to the first sintering heating mechanism 502. The first sintering heating mechanism 502 and the second sintering heating mechanism 305 are used to heat the power device from the top and bottom, respectively.

[0047] The pressure applying mechanism 501 can provide a pressure of 0~30MPa with a pressure control accuracy of ±0.1MPa. The first sintering heating mechanism 502 and the second sintering heating mechanism 305 can both achieve precise temperature control heating of 0~350℃ with a temperature control accuracy of ±0.1℃.

[0048] Among them, the first sealing ring 2, the second sealing ring 4 and the third sealing ring 6 are all high-temperature resistant rubber sealing rings. Of course, they can also be made of other materials as long as they can achieve compression deformation and sealing effects.

[0049] See also Figure 5 The specific working process of the activated formic acid gas protection device for copper sintering of power devices provided by the utility model is as follows:

[0050] Step S1, placing the power device to be copper sintered in a sintering chamber, applying pressure to the upper cover assembly and operating the heating mechanism to press and position the power device to be copper sintered;

[0051] Step S2, closing the mold of the upper cover assembly and the base assembly;

[0052] Step S3: The negative pressure vacuum pump starts to operate to vacuum the sintering chamber;

[0053] When the gas pressure in the sintering chamber is less than or equal to 100 ppm, the negative pressure vacuum port of the sintering chamber is closed.

[0054] Step S4: After the sintering chamber is vacuumed, activated formic acid gas is continuously introduced from the gas inlet;

[0055] The activated formic acid gas is continuously introduced into the sintering chamber to maintain the pressure at 0.1 MPa ~ 0.6 MPa, the flow rate of the activated formic acid gas is 0.1 L / min ~ 5.0 L / min, and the pressure control accuracy is maintained at ±0.01 MPa.

[0056] Step S5, completing the preheating, sintering and cooling processes on the copper sintered power device in an activated formic acid gas protective atmosphere;

[0057] The specific sintering process parameters are as follows: sintering temperature is 230°C-280°C, sintering pressure is 10 MPa-30 MPa, and sintering time is 3 min-10 min.

[0058] Step S6, the formic acid waste gas in the sintering chamber is discharged from the waste gas outlet, and the formic acid waste gas is purified;

[0059] Among them, when the internal gas pressure of the sintering chamber is ≤100ppm, the exhaust outlet is closed, and the formic acid exhaust gas exhaust treatment is completed.

[0060] Step S7: the sintering chamber cover assembly and the base assembly are opened, pressure is applied, and the heating mechanism is reset to obtain a copper sintered power device product.

[0061] Among them, throughout the entire process, the unique airtight design of the formic acid gas protection device can effectively prevent the leakage of formic acid waste gas during the sintering process or the environmental pollution caused by incomplete treatment of formic acid waste gas, as well as the harm to personnel health. In addition, the device can ensure the stability of the gas pressure inside the chamber during the copper sintering process of power devices, saving the amount of activated formic acid gas.

[0062] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A special activated formic acid gas protection device for copper sintering of power devices, characterized in that: include: An upper cover assembly, comprising an upper cover and a first sealing ring; A base assembly is arranged opposite to the upper cover assembly, and includes a base and a second sealing ring. The upper cover assembly and the base assembly together form a sintering chamber; A first sealing ring positioning groove and a second sealing ring positioning groove are respectively provided on end surfaces on opposite sides of the upper cover and the base; a first flange protruding toward one side of the sintering chamber is formed on a side wall of the first sealing ring positioning groove close to the sintering chamber; a second flange protruding away from the sintering chamber is formed on a side wall of the second sealing ring positioning groove away from the sintering chamber; The first sealing ring is arranged in the first sealing ring positioning groove, and the second sealing ring is arranged in the second sealing ring positioning groove. When the upper cover assembly and the base assembly are in the covered state, the first flange is embedded in the second sealing ring positioning groove and is in sealing contact with the second sealing ring, and the second flange is embedded in the first sealing ring positioning groove and is in sealing contact with the first sealing ring.

2. The activated formic acid gas protection device for copper sintering of power devices according to claim 1, characterized in that: The first sealing ring positioning groove is recessed along the height direction of the upper cover, and the height of the side wall of the first sealing ring positioning groove close to the sintering chamber is greater than the height of the side wall away from the sintering chamber; The second sealing ring positioning groove is recessed along the height direction of the base, and the height of the side wall of the second sealing ring positioning groove close to the sintering chamber is smaller than the height of the side wall away from the sintering chamber.

3. The activated formic acid gas protection device for copper sintering of power devices according to claim 2, characterized in that: The height of the side wall of the first sealing ring positioning groove close to the sintering chamber is equal to the height of the side wall of the second sealing ring positioning groove away from the sintering chamber.

4. The activated formic acid gas protection device for copper sintering of power devices according to any one of claims 1 to 3, characterized in that: When the upper cover assembly and the base assembly are in the covered state, the end surface of the upper cover corresponding to the first sealing ring positioning groove away from the sintering chamber is tightly fitted with the end surface of the base corresponding to the second sealing ring positioning groove away from the sintering chamber.

5. The activated formic acid gas protection device for copper sintering of power devices according to claim 1, characterized in that: The first sealing ring and the second sealing ring are both rubber sealing rings.

6. The activated formic acid gas protection device for copper sintering of power devices according to claim 1, characterized in that: The upper cover assembly further includes a pressure applying and heating mechanism and a third sealing ring. A through hole is provided on the top of the upper cover, and the pressure applying and heating mechanism is passed through the through hole on the upper cover. Wherein, a third sealing ring positioning groove is provided on the inner wall of the through hole, and the third sealing ring is arranged in the third sealing ring positioning groove and is in sealing contact with the side wall of the pressure applying and heating mechanism.

7. The activated formic acid gas protection device for copper sintering of power devices according to claim 6, characterized in that: The third sealing ring is a rubber sealing ring.

8. The activated formic acid gas protection device for copper sintering of power devices according to claim 6, characterized in that: The pressure applying and heating mechanism includes a pressure applying mechanism and a first sintering heating mechanism, wherein the first sintering heating mechanism is arranged at one end of the pressure applying mechanism close to the base; A second sintering heating mechanism corresponding to the first sintering heating mechanism is provided in the base. The first sintering heating mechanism and the second sintering heating mechanism are used to heat the power device from the top and bottom of the power device respectively.

9. The activated formic acid gas protection device for copper sintering of power devices according to claim 1, characterized in that: A gas inlet is provided on the side wall of the upper cover, and the gas inlet is connected to an external formic acid activation gas device for introducing activated formic acid gas into the sintering chamber; A negative pressure vacuum port and a waste gas exhaust port are provided on the side wall of the base. The negative pressure vacuum port is connected to an external vacuum pump and is used to evacuate the sintering chamber to form a negative pressure; the waste gas exhaust port is connected to an external formic acid waste gas exhaust system and is used to exhaust the formic acid waste gas in the sintering chamber.

10. The activated formic acid gas protection device for copper sintering of power devices according to claim 1, characterized in that: The cross-sectional shapes of the first flange and the second flange are both semicircular.

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