A method for preparing a high-power device packaging material and applications thereof

Abstract

This invention relates to the field of semiconductor packaging technology, specifically to a method for preparing and applying packaging materials for high-power devices. By utilizing packaging materials with paramagnetic materials (iron oxide, cobalt powder, and nickel powder), the field strength and withstand voltage are optimized, and heat dissipation is improved. Simultaneously, a conductive layer (conductive graphite paper) is added to absorb electromagnetic waves, reducing stray inductance and improving device reliability. Furthermore, before potting the packaging material, a ceramic layer is magnetically sputtered to enhance the lattice order, increase the resistivity of the power device during operation, and further improve the device's withstand voltage and reliability.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging technology, specifically to a method for preparing and applying packaging materials for high-power devices. Background Technology

[0002] As the power of high-power devices gradually increases, the heat generation and electric field strength of these devices also increase accordingly. Consequently, the requirements for the temperature resistance and insulation performance of encapsulation silicone gels are becoming increasingly stringent. Currently used silicone gels are no longer sufficient to meet the application requirements of new electronic components. For example, in the rapidly developing high-power SiC-type IGBT (Insulated Gate Bipolar Transistor) devices and high-power IGBT modules, the encapsulation resin is easily ionized under continuous high voltage output, leading to short circuits and arcing between the device chips, resulting in breakdown and burnout. Therefore, in high-voltage encapsulation processes, the insulation and voltage withstand performance of the encapsulation material are subject to higher requirements, and currently commonly used encapsulation materials such as silicone gel and epoxy resin are no longer adequate for high-voltage applications. Summary of the Invention

[0003] The technical problem of this invention is that conventional packaging materials can no longer meet the requirements of high-voltage applications, and there is an urgent need for a new type of packaging material with high voltage resistance.

[0004] The basic solution provided by this invention is a method for preparing packaging materials for high-power devices, comprising the following steps:

[0005] S101: Mix 10-20 parts by weight of 100nm silicon dioxide with 1-5 parts by weight of 30-50nm iron powder and 1-5 parts by weight of 200-500nm ceramic powder, and grind using a ball mill for 5-30 minutes.

[0006] S102: Add sodium silicate solution to the ground powder until a flowable slurry is formed, and grind it with a ball mill for 10-30 minutes.

[0007] S103: Add 5-20 parts by weight of sodium silicate solution during the grinding process to make the viscosity of the encapsulation material 5000-6000 cP.

[0008] The principle and advantages of this invention are as follows: This solution adds iron powder (Fe3O4, cobalt powder or nickel powder) to the packaging material. It utilizes the characteristic that the magnetic soft magnetic material will generate eddy currents in the magnetic field generated by the current. The eddy current induces a magnetic field opposite to the direction of the external magnetic field to reduce the strength of the external magnetic field. This not only optimizes the field strength and withstand voltage, but also improves the heat dissipation capacity of the packaging material.

[0009] The application of a high-power device packaging material includes the following steps:

[0010] S201: Place the high-power semiconductor module in a Plasma cleaner for 5-10 minutes to remove residues or other impurities generated during the soldering of the surface chips;

[0011] S202: Inject any of the above-mentioned high-power device packaging materials into a high-power semiconductor module, and vacuum degas it for 10-30 minutes under a pressure of 0.08-0.1MPa;

[0012] S203: After degassing, vacuum at 30-50℃ and cure at 0.08-0.1MPa pressure for 30-60 minutes;

[0013] S204: After curing, vacuum is applied at 50-90℃ and curing continues for 30-60 minutes under a pressure of 0.08-0.1MPa. Then, the film is removed to complete the encapsulation of high-power semiconductor devices.

[0014] Furthermore, in step S202, conductive graphite paper is also placed in the high-power semiconductor module.

[0015] Beneficial effects: By absorbing electromagnetic waves through the conductive layer (conductive graphite paper), the stray inductance of the device is reduced, and the reliability of the device is improved.

[0016] Furthermore, in S201, the high-power semiconductor module has a ceramic layer plated on the power chip, the bonding wire, and the DBC board on the side where the power chip and the bonding wire are soldered.

[0017] Furthermore, the high-power semiconductor module undergoes ceramic layer deposition using a magnetic sputtering process, including the following steps:

[0018] A. Place the high-power semiconductor module in a Plasma cleaner for 5-10 minutes to remove surface DBC, chips, and residues or other impurities generated during bonding wire surface soldering.

[0019] B. Place the high-power semiconductor module into the magnetic sputtering coating vacuum chamber, and sequentially turn on the mechanical pump and molecular pump to evacuate the chamber to 1×10⁻⁶. -3 After Pa, heat the DBC plate to 80-100℃;

[0020] C. After the temperature stabilizes, introduce inert gas into the vacuum chamber, set the flow rate of the inert gas, and adjust the gas pressure in the vacuum chamber to 4-6 Pa.

[0021] D. Turn on the intermediate frequency power supply, using 5-10W cm -2 Sputtering at low power removes impurities from the target surface;

[0022] E. Once the glow discharge has stabilized, introduce oxygen and increase the sputtering power to 12-15 W / cm². -2 The baffle on the target is opened to perform sputtering and form the ceramic layer.

[0023] Beneficial effects: By depositing a ceramic layer through magnetic sputtering, the orderliness of the crystal lattice arrangement is improved, the resistivity of the power device during operation is increased, and the withstand voltage and reliability of the device are further improved. Attached Figure Description

[0024] Figure 1 This is a flowchart illustrating the steps of a method for preparing a high-power device packaging material according to Embodiment 1 of the present invention.

[0025] Figure 2 This is a schematic diagram of the materials in Embodiment 1 of the method for preparing a high-power device packaging material according to the present invention.

[0026] Figure 3 This is a flowchart illustrating the steps of a third application embodiment of the high-power device packaging material of the present invention.

[0027] Figure 4 This is a schematic diagram of the packaging of a high-power device packaging material according to the present invention, in a third embodiment. Detailed Implementation

[0028] The following detailed description illustrates the specific implementation methods:

[0029] The specific implementation process is as follows:

[0030] Example 1

[0031] Example 1 is basically as shown in the attached document. Figure 1 As shown, a method for preparing a high-power device packaging material includes the following steps:

[0032] S101: Mix 10 parts by weight of 100nm silicon dioxide with 1 part by weight of 30nm iron powder and 1 part by weight of 200nm ceramic powder, and grind using a ball mill for 5 minutes.

[0033] S102: Add 10 parts by weight of sodium silicate solution to the ground powder until a flowable slurry is formed, and grind it for 10 minutes using a ball mill.

[0034] S103: During the grinding process, add 5 parts by weight of sodium silicate solution to bring the viscosity of the encapsulation material to 5000 cP, obtaining the desired result. Figure 2 The packaging material shown.

[0035] Specifically, in this embodiment, the sodium silicate solution concentration is 100 g / L, and the iron powder in S101 is one or more of iron(III) oxide, cobalt powder, or nickel powder; iron(III) oxide is used in this embodiment. The ceramic powder is one or more of alumina, aluminum nitride, and silicon carbide; silicon carbide is used in this embodiment.

[0036] This solution incorporates iron powder (Fe3O4, cobalt powder, or nickel powder) into the packaging material. Utilizing the characteristic of magnetic soft magnetic materials generating eddy currents in a magnetic field produced by an electric current, this eddy current induces a magnetic field opposite to the external magnetic field, reducing its strength. This not only optimizes the field strength and withstand voltage but also improves the heat dissipation of the packaging material. Furthermore, the alkaline substances in the packaging material react with silicon dioxide, binding the ceramic powder particles together. Further mixing with iron powder optimizes the field strength, increases heat dissipation channels, and enhances the device's withstand voltage, while also improving the overall heat dissipation capacity.

[0037] Based on the preparation method of the high-power device packaging material in the above embodiments, and compared with the conventional packaging material silicon gel in the prior art, the results are shown in Table 1-1:

[0038] Table 1-1 Comparison of Packaging Material Performance

[0039]

[0040] As can be seen from the comparative data in Table 1-1, the encapsulation material provided in this embodiment has higher insulation strength and volume resistivity than the conventional encapsulation material silicone gel in the prior art. It can effectively improve the dielectric strength and volume resistivity of power devices, and significantly improve the withstand voltage and performance of the devices.

[0041] Example 2

[0042] Example 2 is a method for preparing a high-power device packaging material, including the following steps:

[0043] S101: Mix 20 parts by weight of 100nm silicon dioxide with 5 parts by weight of 50nm iron powder and 5 parts by weight of 500nm ceramic powder, and grind using a ball mill for 30 minutes.

[0044] S102: Add 50 parts by weight of sodium silicate solution to the ground powder until a flowable slurry is formed, and grind it using a ball mill for 30 minutes.

[0045] S103: During the grinding process, 20 parts by weight of sodium silicate solution are added to make the viscosity of the encapsulation material 6000 cP, thereby obtaining the encapsulation material.

[0046] Specifically, in this embodiment, the sodium silicate solution concentration is 100 g / L, and the iron powder in S101 is one or more of iron(III) oxide, cobalt powder, or nickel powder; in this embodiment, cobalt powder is used. The ceramic powder is one or more of alumina, aluminum nitride, and silicon carbide; in this embodiment, aluminum nitride is used.

[0047] This solution incorporates iron powder (Fe3O4, cobalt powder, or nickel powder) into the packaging material. Utilizing the characteristic of magnetic soft magnetic materials generating eddy currents in a magnetic field produced by an electric current, this eddy current induces a magnetic field opposite to the external magnetic field, reducing its strength. This not only optimizes the field strength and withstand voltage but also improves the heat dissipation of the packaging material. Furthermore, the alkaline substances in the packaging material react with silicon dioxide, binding the ceramic powder particles together. Further mixing with iron powder optimizes the field strength, increases heat dissipation channels, and enhances the device's withstand voltage, while also improving the overall heat dissipation capacity.

[0048] Based on the preparation method of the high-power device packaging material in this embodiment, and compared with the conventional packaging material silicon gel in the prior art, the results are shown in Table 1-2:

[0049] Table 1-2 Comparison of Packaging Material Performance Table 2

[0050]

[0051] As can be seen from the comparative data in Table 1-2, the encapsulation material provided in this embodiment has higher insulation strength and volume resistivity than the conventional encapsulation material silicone gel in the prior art. It can effectively improve the dielectric strength and volume resistivity of power devices, and significantly improve the withstand voltage and performance of the devices.

[0052] Example 3

[0053] Example 3 is basically as shown in the appendix. Figure 3 As shown, the application of a high-power device packaging material includes the following steps:

[0054] S201: Place the high-power semiconductor module in a Plasma cleaner for 5 minutes to remove residues or other impurities generated during the soldering of the surface chips;

[0055] S202: Inject any of the above-mentioned high-power device packaging materials into a high-power semiconductor module and degas it under vacuum for 10 minutes at a pressure of 0.08 MPa;

[0056] S203: After degassing, vacuum at 30℃ and cure at 0.08MPa pressure for 30 minutes;

[0057] S204: After curing, vacuum is applied at 50°C and curing continues for 30 minutes under a pressure of 0.08MPa. Then, the film is removed to complete the encapsulation of the high-power semiconductor device.

[0058] Specifically, such as Figure 4 As shown, before the encapsulation material is injected into the high-power semiconductor module, there is also conductive graphite paper in the high-power semiconductor module. The conductive layer (conductive graphite paper) absorbs electromagnetic waves, reduces the stray inductance of the device, and improves the reliability of the device.

[0059] In addition, in this embodiment, before S201, the high-power semiconductor module undergoes ceramic layer deposition on the power chip, bonding wires, and the DBC board on the side where the power chip and bonding wires are soldered using a magnetic sputtering process, including the following steps:

[0060] A. Place the high-power semiconductor module in a Plasma cleaner for 5 minutes to remove surface DBC, chips, and residues or other impurities generated during bonding wire surface soldering.

[0061] B. Place the high-power semiconductor module into the magnetic sputtering coating vacuum chamber, and sequentially turn on the mechanical pump and molecular pump to evacuate the chamber to 1×10⁻⁶. -3 After Pa, heat the DBC plate to 80℃;

[0062] C. After the temperature stabilizes, introduce inert argon gas into the vacuum chamber, set the inert gas flow rate, and adjust the pressure in the vacuum chamber to 4 Pa.

[0063] D. Turn on the intermediate frequency power supply and use 5W cm -2 Low-power sputtering is used to remove impurities from the surface of the alumina target.

[0064] E. Once the glow discharge has stabilized, introduce oxygen and increase the sputtering power to 12W cm⁻¹. -2 The baffle on the alumina target is opened to perform sputtering and form the ceramic layer.

[0065] Based on the preparation method and application of the high-power device packaging material in the above embodiments, and comparing the results with those of the conventional packaging material silicon gel after encapsulation, the results are shown in Table 3-1:

[0066] Table 3-1 Comparison of Packaging Material Performance

[0067]

[0068] As can be seen from the comparative data in Table 1-1, the encapsulation material provided in this application, compared with the conventional encapsulation material silicon gel in the prior art, can effectively improve the dielectric strength and volume resistivity of power devices, and significantly improve the device's withstand voltage and performance.

[0069] Example 4

[0070] Example 4 illustrates the application of a high-power device packaging material, including the following steps:

[0071] S201: Place the high-power semiconductor module in a Plasma cleaner for 10 minutes to remove residues or other impurities generated during the soldering of the surface chips;

[0072] S202: Inject any of the above-mentioned high-power device packaging materials into a high-power semiconductor module and vacuum degas it for 30 minutes under a pressure of 0.1 MPa;

[0073] S203: After degassing, vacuum at 50℃ and cure at 0.1MPa pressure for 60min;

[0074] S204: After curing, vacuum is applied at 90°C and curing continues for 60 minutes under 0.1MPa pressure. Then, the film is removed to complete the encapsulation of the high-power semiconductor device.

[0075] Specifically, before the packaging material is injected into the high-power semiconductor module, there is also conductive graphite paper in the high-power semiconductor module. The conductive layer (conductive graphite paper) absorbs electromagnetic waves, reduces stray inductance of the device, and improves the reliability of the device.

[0076] In addition, in this embodiment, before S201, the high-power semiconductor module undergoes ceramic layer deposition on the power chip, bonding wires, and the DBC board on the side where the power chip and bonding wires are soldered using a magnetic sputtering process, including the following steps:

[0077] A. Place the high-power semiconductor module in a Plasma cleaner for 10 minutes to remove surface DBC, chips, and residues or other impurities generated during bonding wire surface soldering.

[0078] B. Place the high-power semiconductor module into the magnetic sputtering coating vacuum chamber, and sequentially turn on the mechanical pump and molecular pump to evacuate the chamber to 1×10⁻⁶. -3 After Pa, heat the DBC plate to 100℃;

[0079] C. After the temperature stabilizes, introduce inert argon gas into the vacuum chamber, set the inert gas flow rate, and adjust the pressure in the vacuum chamber to 6 Pa.

[0080] D. Turn on the intermediate frequency power supply and use 10W cm -2 Low-power sputtering is used to remove impurities from the surface of the alumina target.

[0081] E. Once the glow discharge has stabilized, introduce oxygen and increase the sputtering power to 15W cm⁻¹.-2 The baffle on the alumina target is opened to perform sputtering and form the ceramic layer.

[0082] By forming a ceramic layer through magnetic sputtering on the copper layer of the power chip, the power chip, and the bonding lines, the orderliness of the crystal arrangement is improved, the resistivity of the power device during operation is increased, and the withstand voltage and reliability of the device are further improved.

[0083] Based on the preparation method and application of the high-power device packaging material in the above embodiments, and comparing the results with those of the conventional packaging material silicon gel after encapsulation, the results are shown in Table 4-1:

[0084] Table 4-1 Comparison of Packaging Material Performance Table 4

[0085]

[0086] As can be seen from the comparative data in Table 1-1, the encapsulation material provided in this application, compared with the conventional encapsulation material silicon gel in the prior art, can effectively improve the dielectric strength and volume resistivity of power devices, and significantly improve the device's withstand voltage and performance.

[0087] The above are merely embodiments of the present invention. Commonly known structures and characteristics are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for preparing a high-power device packaging material, characterized in that, Including the following steps: S101: Mix 10-20 parts by weight of 100nm silicon dioxide with 1-5 parts by weight of 30-50nm iron powder and 1-5 parts by weight of 200-500nm ceramic powder, and grind using a ball mill for 5-30 minutes. S102: Add sodium silicate solution to the ground powder until a flowable slurry is formed, and grind it with a ball mill for 10-30 minutes. S103: Add 5-20 parts by weight of sodium silicate solution during the grinding process to make the viscosity of the encapsulation material 5000-6000 cP; In S101, the iron powder is one or more of iron(II,III) oxide, cobalt powder, or nickel powder.

2. The method for preparing a high-power device packaging material according to claim 1, characterized in that: In S101, the ceramic powder is one or more of alumina, aluminum nitride, and silicon carbide.

3. The method for preparing a high-power device packaging material according to claim 1, characterized in that: In step S102, the added sodium silicate solution is in the form of 10-50 parts by mass.

4. The method for preparing a high-power device packaging material according to claim 1, characterized in that: The concentration of the sodium silicate solution is 100 g / L.

5. An application of a high-power device packaging material, characterized in that, Including the following steps: S201: Place the high-power semiconductor module in a Plasma cleaner for 5-10 minutes to remove residues or other impurities generated during the soldering of the surface chips; S202: Inject any one of the high-power device packaging materials of claims 1-4 into a high-power semiconductor module, and vacuum degas it for 10-30 minutes under a pressure of 0.08-0.1MPa; S203: After degassing, vacuum at 30-50℃ and cure at 0.08-0.1MPa pressure for 30-60 minutes; S204: After curing, vacuum is applied at 50-90℃ and curing continues for 30-60 minutes under a pressure of 0.08-0.1MPa. Then, the film is removed to complete the encapsulation of high-power semiconductor devices.

6. The application of the high-power device packaging material according to claim 5, characterized in that: In step S202, conductive graphite paper is also placed in the high-power semiconductor module.

7. The application of a high-power device packaging material according to claim 5, characterized in that: In S201, the high-power semiconductor module has a ceramic layer plated on the power chip, bonding wire, and the DBC board on the side where the power chip and bonding wire are soldered.

8. The application of a high-power device packaging material according to claim 7, characterized in that: High-power semiconductor modules undergo ceramic layer deposition using a magnetic sputtering process, including the following steps: A. Place the high-power semiconductor module in a Plasma cleaner for 5-10 minutes to remove surface DBC, chips, and residues or other impurities generated during bonding wire surface soldering. B. Place the high-power semiconductor module into the magnetic sputtering coating vacuum chamber, and sequentially turn on the mechanical pump and molecular pump to evacuate the chamber until... After Pa, heat the DBC plate to 80-100℃; C. After the temperature stabilizes, introduce inert gas into the vacuum chamber, set the flow rate of the inert gas, and adjust the gas pressure in the vacuum chamber to 4-6 Pa. D. Turn on the intermediate frequency power supply and use 5-10 Sputtering at low power removes impurities from the target surface; E. Once the glow discharge has stabilized, introduce oxygen and increase the sputtering power to 12-15. The baffle on the target is opened to perform sputtering and form the ceramic layer.

9. The application of a high-power device packaging material according to claim 8, characterized in that: In step C, argon is used as the inert gas.

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