Sulfur prevention treatment method for IGBT (Insulated Gate Bipolar Translator) module

Abstract

The invention discloses an anti-sulfur treatment method for an IGBT module. The anti-sulfur treatment method comprises the following steps: step 1, carrying out nickel plating treatment on a ceramic-copper substrate; step 2, attaching a chip to the nickel-plated ceramic-copper substrate, and after bonding, coating three-proofing lacquer on the surfaces of the aluminum wire and the ceramic-copper substrate after bonding by adopting a coating process; thirdly, sulfur-proof silica gel is poured in the gel pouring procedure; and step 4, after the IGBT module is packaged, sealant is coated at the installation contact part of the outer upper cover and the shell of the IGBT module. By adopting the anti-sulfur treatment method of the IGBT module, the hydrogen sulfide gas can be effectively prevented from entering the module to be in contact with the DBC copper layer to generate copper sulfide crystals, the corrosion of the hydrogen sulfide gas to the internal structure of the module is reduced, the use performance of the module in a severe environment containing the copper sulfide gas is improved, and the service life of the IGBT module is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of IGBT module anti-sulfurization, and in particular to an IGBT module anti-sulfurization treatment method. Background Art

[0002] Based on the development experience of offshore wind power and photovoltaic power generation in recent years and some failure cases, hydrogen sulfide is a relatively common corrosive gas encountered in the service of offshore wind power and photovoltaic power generation units. After hydrogen sulfide is produced in the sea area near wind power and photovoltaic power generation units, it will enter the device through seawater evaporation, sea wave spray, etc. After entering the device, it will accumulate at the base layer because its density is greater than that of air, causing harm to personnel and equipment.

[0003] Hydrogen sulfide can penetrate the silicone gel and reach the DCB under the high temperature of normal operation of the IGBT module. Under the action of high humidity and applied voltage, H2S can react with the copper in the DCB groove to generate Cu2S crystals, causing the Cu2S crystals to grow electrically. Since Cu2S crystals are conductive, they will cause the insulation withstand voltage of the IGBT module to decrease, or even short-circuit failure. Some of the hydrogen atoms generated by the reaction will form hydrogen gas and be discharged, while the other part of the hydrogen atoms will not be discharged in time and will penetrate into the metal lattice through adsorption, diffusion and other effects inside the IGBT, causing hydrogen damage, or hydrogen embrittlement, which will also affect the service life of the IGBT module. Summary of the invention

[0004] The object of the present invention is to provide an anti-sulfur treatment method for an IGBT module in view of the deficiencies in the prior art.

[0005] To achieve the above object, the technical solution adopted by the present invention is:

[0006] Provided is an anti-sulfur treatment method for an IGBT module, comprising the following steps:

[0007] Step 1, nickel-plating the ceramic-copper substrate to form an isolation layer for isolating H2S on the surface copper layer of the ceramic-copper substrate, so as to prevent H2S corrosion;

[0008] Step 2: attach the chip to the nickel-plated ceramic-copper substrate. After bonding, use a coating process to coat the aluminum wire and the ceramic-copper substrate with conformal coating.

[0009] Step 3: Inject anti-sulfur silica gel during the glue injection process to prevent H2S gas from entering the DBC surface;

[0010] Step 4: After the IGBT module is packaged, apply sealant to the contact point between the external upper cover and the housing of the IGBT module to prevent H2S gas from entering the interior of the IGBT module.

[0011] Furthermore, in step 1, the specific steps of the nickel plating treatment are:

[0012] The surface of the ceramic-copper substrate is thoroughly cleaned, a protective film is applied to the part that does not need nickel plating, and then it is washed with dilute sulfuric acid solution and pure water in turn;

[0013] The cleaned ceramic-copper substrate is activated in a palladium chloride activation solution, rinsed with pure water, and then placed in a nickel plating solution for chemical nickel plating;

[0014] After nickel plating, wash with pure water, remove the water on the surface with an air gun, put it in an oxygen-free oven and dry it.

[0015] Furthermore, the concentration of the dilute sulfuric acid solution is 8-10wt%, and the cleaning time is 5-10min; the activation time in the palladium chloride activation solution is 4-6min; the chemical nickel plating time is 40-60min, the temperature is 100-110°C, and the solution pH value is controlled at 4.7-5.2; the temperature of the oven is set to 100-110°C, and the baking time is 30-40min.

[0016] Furthermore, in step 2, the specific coating process steps of applying the three-proof paint are: filtering the three-proof paint with a 200-300 mesh gauze and pouring it into a spray pot, adjusting the air pressure and spray shape of the spray gun, making the spray gun nozzle at a 45° angle to the surface of the ceramic-copper substrate, and moving the spray gun at a constant speed for spraying; after spraying, let it stand for 5-10 minutes, then send it to the baking oven, set the temperature to 80-85°C, and bake for 10-20 minutes.

[0017] Furthermore, the thickness of the conformal coating is 30-40 microns.

[0018] Furthermore, in step three, the mass ratio of the silica gel base material to the anti-sulfur agent in the anti-sulfur silica gel is 100:(5-8).

[0019] Furthermore, in step three, the mass of the anti-sulfur silica gel used in one IGBT module is 28-35g.

[0020] Furthermore, in step 4, the weight of the sealant used is 5-10g.

[0021] Furthermore, in step 4, after applying the sealant, the IGBT module is placed in a high-temperature oxygen-free oven, and the temperature is set to 120-125° C. for 2-2.5 hours.

[0022] The present invention adopts the above technical solution, and has the following technical effects compared with the prior art:

[0023] The anti-sulfur treatment method of the IGBT module of the present invention can effectively prevent hydrogen sulfide gas from entering the interior of the module and contacting the DBC copper layer to generate copper sulfide crystals, reduce the corrosion of the internal structure of the module by hydrogen sulfide gas, improve the performance of the module in a harsh environment containing copper sulfide gas, and extend the service life of the IGBT module. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a schematic diagram of an IGBT module after adopting the anti-sulfur treatment method of the present invention.

[0025] Figure 2 It is a schematic diagram of an IGBT module (the contact point between the external upper cover and the housing installation) after the anti-sulfur treatment method of the present invention is adopted. DETAILED DESCRIPTION

[0026] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments, but is not intended to be limiting of the present invention. It should be noted that the embodiments and features in the embodiments of the present invention may be combined with each other without conflict.

[0027] refer to Figure 1-2 This embodiment provides an anti-sulfur treatment method for an IGBT module, comprising the following steps:

[0028] Step 1, nickel-plating the ceramic-copper substrate 1 to form an isolation layer for isolating H2S on the surface copper layer of the ceramic-copper substrate, so as to prevent H2S corrosion;

[0029] Step 2: attach the chip to the nickel-plated ceramic-copper substrate 1. After bonding, use a coating process to coat the aluminum wire and the ceramic-copper substrate with conformal coating to form a conformal coating 2 with a thickness of 30-40 microns.

[0030] Step 3: In the glue pouring process, anti-sulfur silica gel 3 is poured to prevent H2S gas from entering the DBC surface;

[0031] Step 4: After the IGBT module is packaged, a sealant 4 is applied to the contact point between the external upper cover and the housing of the IGBT module to prevent H2S gas from entering the interior of the IGBT module.

[0032] The specific steps of nickel plating are:

[0033] The surface of the ceramic-copper substrate is thoroughly cleaned, a protective film is applied to the part that does not need nickel plating, and then it is washed with dilute sulfuric acid solution and pure water in turn;

[0034] The cleaned ceramic-copper substrate is activated in a palladium chloride activation solution, rinsed with pure water, and then placed in a nickel plating solution for chemical nickel plating;

[0035] After nickel plating, wash with pure water, remove the water on the surface with an air gun, put it in an oxygen-free oven and dry it.

[0036] By adopting the above process, an isolation layer is provided between the copper layer on the surface of the DBC and the H2S-containing gas, thereby preventing corrosion from the hydrogen sulfide gas.

[0037] In a preferred embodiment, the concentration of the dilute sulfuric acid solution is 8-10wt%, more preferably 8wt%; the cleaning time is 5-10min, more preferably 5min; the activation time in the palladium chloride activation solution is 4-6min, more preferably 4min; the chemical nickel plating time is 40-60min (more preferably 40min), the temperature is 100-110°C (more preferably 100°C), the solution is tablet, and the pH value is controlled at 4.7-5.2; the temperature of the oven is set to 100-110°C (more preferably 100°C), and the baking time is 30-40min (more preferably 30min).

[0038] The specific coating process steps for applying the three-proof paint are: filtering the three-proof paint with a 200-300 mesh (more preferably 200 mesh) gauze and pouring it into a spray pot, adjusting the air pressure and spray shape of the spray gun, and making the spray gun nozzle 45° away from the surface of the ceramic-copper substrate, and moving the spray gun at a constant speed for spraying; after spraying, let it stand for 5-10 minutes (more preferably 5 minutes), and then send it to the baking oven, set the temperature to 80-85°C (more preferably 80°C), and bake for 10-20 minutes (more preferably 10 minutes).

[0039] Through the above coating process, a 30-40 micron thick conformal coating is formed on the surface of the aluminum wire and the ceramic-copper substrate after bonding, forming an insulating protective layer to further prevent H2S gas from contacting the DBC surface.

[0040] Anti-sulfur silica gel is a special silica gel material with excellent resistance to sulfide corrosion. It can maintain stable physical and chemical properties in an environment containing sulfides. It is widely used in the petroleum, chemical, electric power and other industries, especially in contact with sulfides such as hydrogen sulfide. The ratio of anti-sulfur silica gel should be determined according to the specific application requirements and raw material properties. Generally speaking, the amount of anti-sulfur agent added should be within a certain range. Too much or too little may affect the anti-sulfur effect. During the mixing process, the process conditions, including temperature and stirring speed, should be strictly controlled to ensure uniform mixing and stable performance.

[0041] The scenario containing hydrogen sulfide applicable to the method of the present invention is: temperature 85°C, humidity 85%, H2S concentration 25ppm. For this application scenario, the ratio of anti-sulfur silica gel used in the method of the present invention is silica gel base material: anti-sulfur agent = 100:5 (mass ratio). During the proportioning process, the silica gel base material is first added to the agitator, the temperature is maintained at 25°C, and then the anti-sulfur agent is added according to the proportion, and fully stirred at a stirring speed of 40 rpm until mixed evenly. After testing, the anti-sulfur silica gel has long-term stability in an environment of temperature 85°C, humidity 85%, and H2S concentration 25ppm. The mass of anti-sulfur silica gel used in an IGBT module in this embodiment is 28-35g (preferably 28g).

[0042] In the method of the present invention, the weight of the sealant used is 5-10g (preferably 5g). After applying the sealant, the IGBT module is placed in a high-temperature oxygen-free oven, set at 120-125°C (preferably 120°C) for 2-2.5h (preferably 2h). The better the sealing performance of the sealant, the better the anti-sulfur effect.

[0043] The above description is only a preferred embodiment of the present invention, and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of the specification and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for anti-sulfurization of an IGBT module, characterized in that: The steps include: Step 1, nickel-plating the ceramic-copper substrate to form an isolation layer for isolating H2S on the surface copper layer of the ceramic-copper substrate, so as to prevent H2S corrosion; Step 2: attach the chip to the nickel-plated ceramic-copper substrate. After bonding, use a coating process to coat the aluminum wire and the ceramic-copper substrate with conformal coating. Step 3: Inject anti-sulfur silica gel during the glue injection process to prevent H2S gas from entering the DBC surface; Step 4: After the IGBT module is packaged, apply sealant to the contact point between the external upper cover and the housing of the IGBT module to prevent H2S gas from entering the interior of the IGBT module.

2. The anti-sulfur treatment method for an IGBT module according to claim 1, characterized in that: In step 1, the specific steps of the nickel plating process are: The surface of the ceramic-copper substrate is thoroughly cleaned, a protective film is applied to the part that does not need nickel plating, and then it is washed with dilute sulfuric acid solution and pure water in turn; The cleaned ceramic-copper substrate is activated in a palladium chloride activation solution, rinsed with pure water, and then placed in a nickel plating solution for chemical nickel plating; After nickel plating, wash with pure water, remove the water on the surface with an air gun, put it in an oxygen-free oven and dry it.

3. The anti-sulfur treatment method for an IGBT module according to claim 2, characterized in that: The concentration of the dilute sulfuric acid solution is 8-10wt%, and the cleaning time is 5-10min; the activation time in the palladium chloride activation solution is 4-6min; the chemical nickel plating time is 40-60min, the temperature is 100-110°C, and the solution pH value is controlled at 4.7-5.2; the temperature of the oven is set to 100-110°C, and the baking time is 30-40min.

4. The anti-sulfur treatment method for an IGBT module according to claim 1, characterized in that: In step 2, the specific coating process steps of applying the three-proof paint are: filter the three-proof paint with a 200-300 mesh gauze and pour it into a spray pot, adjust the air pressure and spray shape of the spray gun, and make the spray gun nozzle at a 45° angle to the surface of the ceramic-copper substrate, and move the spray gun at a constant speed for spraying; after spraying, let it stand for 5-10 minutes, then send it to the baking oven, set the temperature to 80-85°C, and bake for 10-20 minutes.

5. The anti-sulfur treatment method for an IGBT module according to claim 4, characterized in that: The thickness of the conformal coating is 30-40 microns.

6. The anti-sulfur treatment method for an IGBT module according to claim 1, characterized in that: In step three, the mass ratio of the silica gel base material to the anti-sulfur agent in the anti-sulfur silica gel is 100:(5-8).

7. The anti-sulfur treatment method for an IGBT module according to claim 1, characterized in that: In step 3, the mass of anti-sulfur silica gel used in one IGBT module is 28-35g.

8. The anti-sulfur treatment method for an IGBT module according to claim 1, characterized in that: In step 4, the weight of the sealant used is 5-10g.

9. The anti-sulfur treatment method for an IGBT module according to claim 1, characterized in that: In step 4, after applying the sealant, place the IGBT module in a high-temperature oxygen-free oven, set the temperature to 120-125°C, and the time to 2-2.5 hours.

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