Processing method for improving stability of tantalum capacitor

Abstract

The invention discloses a treatment method for improving the stability of a tantalum capacitor, and the method comprises the following steps: mixing electronic glue with a diluent, and obtaining an impregnant; the tantalum core is immersed in the impregnant for immersion treatment; and carrying out drying treatment on the impregnated tantalum core. The electronic glue used in the invention has the characteristics of good adhesive property, good mechanical property, high curing speed, good weather resistance, good environmental protection performance and the like. The electronic glue layer mainly plays a moisture-proof role, and the situation that the epoxy resin packaging chip tantalum capacitor absorbs moisture to cause electrical performance parameter change and cannot meet the line design requirement in use when being in a high-temperature and high-humidity environment is avoided.

Description

Technical Field

[0001] The present invention belongs to the technical field of electronic components, and in particular relates to a processing method for improving the stability of tantalum capacitors. Background Art

[0002] Molded encapsulated tantalum chip capacitors, due to their excellent performance, are widely used in military communications, aerospace, aviation, industrial control, film and television equipment, communication instrumentation, and other fields. However, in high-temperature and high-humidity environments, capacitor performance often deteriorates, primarily manifesting as reduced electrical performance and increased leakage current, which seriously affects the capacitor's reliability and service life. Therefore, it is necessary to optimize capacitor production processes and improve capacitor stability.

[0003] Patent application CN100565727C discloses a capacitor impregnant with an additive. By adding an alicyclic epoxy resin to existing capacitor impregnants of benzyltoluene or diarylethane, the additive increases the capacitor's operating field strength from 50 kV / mm to 56 kV / mm, saves 20% of material, and reduces the capacitor's volume by 25%. However, the technical problem of extending the life of capacitors in humid environments is not addressed. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a processing method for improving the stability of tantalum capacitors.

[0005] The present invention is achieved through the following technical solutions.

[0006] The present invention provides a treatment method for improving the stability of tantalum capacitors, which includes an electronic glue impregnation process performed after a carbon layer impregnation process and before a silver paste impregnation process in the production process of tantalum capacitors.

[0007] Preferably, the electronic adhesive dipping process comprises the following steps:

[0008] S1: mixing electronic glue and diluent to obtain an impregnating agent;

[0009] S2: Immersing the tantalum core in an impregnating agent for impregnation treatment;

[0010] S3: The tantalum core after impregnation is dried.

[0011] Preferably, the electronic adhesive includes one or more of organic resin, organic silicone, vulcanized silicone rubber, and epoxy adhesive.

[0012] Preferably, the diluent includes one or more of toluene, silicone oil, mineral oil, and chlorinated paraffin.

[0013] Preferably, the immersion treatment includes a first immersion treatment and a second immersion treatment in sequence, and the number of treatments of the first immersion treatment and the second immersion treatment is ≧1.

[0014] Preferably, the volume ratio of the electronic glue to the diluent in the first dipping treatment is 1:0.5-10.

[0015] Preferably, the volume ratio of the electronic glue to the diluent in the second dipping treatment is 1:0.5-7.

[0016] Preferably, in the first and second impregnation treatments, the impregnation and extraction speeds of the tantalum core are controlled to be 1 mm / 1s to 5s to ensure the penetration and filling amount of the electronic glue.

[0017] Preferably, the drying step includes: dipping the excess electronic glue on the bottom of the tantalum core after the immersion treatment with capacitor paper, placing it at room temperature for 30 minutes to 120 minutes, and then placing it in a drying oven at a constant temperature of 150°C to 250°C for 20 minutes to 150 minutes for drying.

[0018] The beneficial effects of the present invention are:

[0019] The electronic adhesive used in the present invention has excellent bonding and mechanical properties, fast curing, good weather resistance, and environmental performance. The electronic adhesive layer primarily serves as a moisture barrier, preventing the epoxy resin-encapsulated tantalum chip capacitors from absorbing moisture in high-temperature, high-humidity environments, which could cause changes in their electrical performance parameters and render them inoperable in circuit design requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of the structure of a capacitor tantalum core produced using the method of the present invention;

[0021] In the figure: 1 is the anode tantalum block, 2 is the tantalum wire, 3 is the dielectric oxide film layer, 4 is the manganese dioxide layer, 5 is the graphite layer, 6 is the first electronic glue layer, 7 is the silver paste layer, and 8 is the second electronic glue layer. DETAILED DESCRIPTION

[0022] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0023] Example 1:

[0024] A treatment method for improving the stability of tantalum capacitors includes an electronic glue impregnation process performed after a carbon layer impregnation process and before a silver paste impregnation process in the production process of tantalum capacitors.

[0025] The electronic glue impregnation process comprises the following steps:

[0026] S1: mixing electronic glue and diluent to obtain an impregnating agent;

[0027] S2: Immersing the tantalum core in an impregnating agent for impregnation treatment;

[0028] S3: The tantalum core after impregnation is dried.

[0029] The electronic glue is an organic resin.

[0030] The diluent is the original Dow Corning OS-20 silicone oil diluent.

[0031] The dipping treatment includes a first dipping treatment and a second dipping treatment in sequence, and the first dipping treatment and the second dipping treatment are performed once.

[0032] The volume ratio of the electronic glue to the diluent in the first dipping treatment is 1:0.5.

[0033] The volume ratio of the electronic glue and the diluent in the second dipping treatment is 1:2.

[0034] In the first and second dipping treatments, the electronic glue is dipped in slowly and extracted slowly, and the entire tantalum core is submerged in the electronic glue liquid. However, the tantalum core cannot be turned over to avoid contamination of the colloid by the gasket or tantalum wire set on the upper end face of the tantalum core. The dipping and extraction speeds of the tantalum core are controlled at 1mm / 1s to ensure the penetration and filling amount of the electronic glue.

[0035] The drying treatment step includes: using capacitor paper to dip the excess electronic glue on the bottom of the tantalum core after the immersion treatment, placing it at room temperature for 30 minutes, placing it in a drying oven at room temperature, setting the temperature of the drying oven at 150°C, turning on the power of the drying oven after the temperature is set, and keeping the temperature constant for 20 minutes after the temperature slowly rises to the set temperature.

[0036] Example 2:

[0037] A treatment method for improving the stability of tantalum capacitors includes an electronic glue impregnation process performed after a carbon layer impregnation process and before a silver paste impregnation process in the production process of tantalum capacitors.

[0038] The electronic glue impregnation process comprises the following steps:

[0039] S1: mixing electronic glue and diluent to obtain an impregnating agent;

[0040] S2: Immersing the tantalum core in an impregnating agent for impregnation treatment;

[0041] S3: The tantalum core after impregnation is dried.

[0042] The electronic adhesive is vulcanized silicone rubber.

[0043] The diluent is chlorinated paraffin.

[0044] The dipping treatment includes a first dipping treatment and a second dipping treatment in sequence, and the first dipping treatment and the second dipping treatment are performed once.

[0045] The volume ratio of the electronic glue to the diluent in the first dipping treatment is 1:10.

[0046] The volume ratio of the electronic glue to the diluent in the second dipping treatment is 1:7.

[0047] In the first and second dipping treatments, the electronic glue is dipped in slowly and extracted slowly, and the entire tantalum core is submerged in the electronic glue liquid. However, the tantalum core cannot be turned over to avoid contamination of the colloid by the gasket or tantalum wire set on the upper end face of the tantalum core. The dipping and extraction speeds of the tantalum core are controlled at 1mm / 5s to ensure the penetration and filling amount of the electronic glue.

[0048] The drying treatment step includes: dipping the excess electronic glue on the bottom of the tantalum core after the immersion treatment with capacitor paper, placing it at room temperature for 120 minutes, placing it in a drying oven at room temperature, setting the temperature of the drying oven at 250°C, turning on the power of the drying oven after the temperature is set, and keeping the temperature constant for 150 minutes after the temperature slowly rises to the set temperature.

[0049] Example 3:

[0050] A treatment method for improving the stability of tantalum capacitors includes an electronic glue impregnation process performed after a carbon layer impregnation process and before a silver paste impregnation process in the production process of tantalum capacitors.

[0051] The electronic glue impregnation process comprises the following steps:

[0052] S1: mixing electronic glue and diluent to obtain an impregnating agent;

[0053] S2: Immersing the tantalum core in an impregnating agent for impregnation treatment;

[0054] S3: The tantalum core after impregnation is dried.

[0055] The electronic glue is epoxy glue.

[0056] The diluent is toluene.

[0057] The dipping treatment includes a first dipping treatment and a second dipping treatment in sequence, and the first dipping treatment and the second dipping treatment are performed once.

[0058] The volume ratio of the electronic glue to the diluent in the first dipping treatment is 1:6.

[0059] The volume ratio of the electronic glue to the diluent in the second dipping treatment is 1:4.

[0060] In the first and second dipping treatments, the electronic glue is dipped in slowly and extracted slowly, and the entire tantalum core is submerged in the electronic glue liquid. However, the tantalum core cannot be turned over to avoid contamination of the colloid by the gasket or tantalum wire set on the upper end face of the tantalum core. The dipping and extraction speeds of the tantalum core are controlled at 1mm / 2s to ensure the penetration and filling amount of the electronic glue.

[0061] The drying treatment step includes: using capacitor paper to dip the excess electronic glue on the bottom of the tantalum core after the immersion treatment, placing it at room temperature for 80 minutes, placing it in a drying oven at room temperature, setting the temperature of the drying oven to 200°C, turning on the power of the drying oven after the temperature is set, and keeping the temperature constant for 90 minutes after the temperature slowly rises to the set temperature.

[0062] Storage of the impregnating agent: Collect and store in a sealed container in a cool, dry, well-ventilated area, away from direct sunlight and moisture, and away from sources of fire and high temperatures. The storage period is 10 to 180 days.

[0063] The production process of molded packaged tantalum chip capacitors includes:

[0064] A: Tantalum powder and tantalum wire are pressed into a rectangular tantalum block with a certain strength;

[0065] B: Sinter the tantalum block at different temperatures according to the specific volume of the tantalum powder;

[0066] C: forming a tantalum pentoxide dielectric film on the inner and outer surfaces of the porous tantalum block by an electrochemical method to obtain a dielectric oxide film layer 3;

[0067] D: The surface of the tantalum pentoxide dielectric film is immersed in manganese nitrate solutions of different specific gravities and then subjected to high-temperature thermal decomposition to generate manganese dioxide, thereby obtaining a manganese dioxide layer 4;

[0068] E: Impregnating a graphite auxiliary material on the surface of the tantalum block covered with manganese dioxide to obtain a graphite layer 5;

[0069] F: performing a first electronic adhesive impregnation process, impregnating the surface of the graphite layer with electronic adhesive to obtain a first electronic adhesive layer 6;

[0070] G: Impregnate silver paste on the surface of the electronic adhesive, silver paste layer 7;

[0071] H: A second layer of electronic glue is applied to the surface of the silver paste to obtain a second electronic glue layer 8, which completes the extraction of electrical performance parameters of the tantalum core and moisture-proof protection;

[0072] I: After the tantalum core is cut into tantalum wire according to the process, it is bonded to the designed position of the lead frame with bonding silver paste. After high-temperature curing and tantalum wire welding, it is molded and encapsulated with epoxy resin molding material.

[0073] Except for step F, the remaining steps are prior art and will not be described again here.

[0074] The tantalum cores processed in Examples 1 to 3 were used to produce CAK45H type molded packaged chip tantalum capacitors. Figure 1 As shown, it includes a tantalum block 1 and a tantalum wire 2. One end of the tantalum wire 2 is extended into the tantalum block 1 for connection. The outer wall of the tantalum block 1 is sequentially provided with a dielectric oxide film layer 3, a manganese dioxide layer 4, a graphite layer 5, a first electronic glue layer 6, a silver paste layer 7, and a second electronic glue layer 8 from the inside to the outside.

[0075] Comparative Example 1

[0076] The manufacturing process of molded packaged chip tantalum capacitors produced by existing technology includes:

[0077] A: Tantalum powder and tantalum wire are pressed into a rectangular tantalum block with a certain strength;

[0078] B: Sinter the tantalum block at different temperatures according to the specific volume of the tantalum powder;

[0079] C: Forming a tantalum pentoxide dielectric film on the inner and outer surfaces of the porous tantalum block by electrochemical methods to obtain a dielectric oxide film layer;

[0080] D: The surface of the tantalum pentoxide dielectric film is immersed in manganese nitrate solutions of different specific gravities and then subjected to high-temperature thermal decomposition to generate manganese dioxide to obtain a manganese dioxide layer;

[0081] E: Impregnating a graphite auxiliary material on the surface of the tantalum block covered with manganese dioxide to obtain a graphite layer;

[0082] F: Impregnate silver paste on the surface of electronic glue to form a silver paste layer;

[0083] G: Complete the electrical performance parameter drawing and moisture-proof protection of the tantalum core;

[0084] H: After the tantalum core is cut into tantalum wire according to the process, it is bonded to the designed position of the lead frame with bonding silver paste. After high-temperature curing and tantalum wire welding, it is molded and encapsulated with epoxy resin molding material.

[0085] In order to facilitate understanding by those skilled in the art, the present invention will be further described below with reference to the following examples. The examples are merely illustrative of the invention and are not intended to limit the present invention. Any steps not specifically described in the examples are prior art and will not be described in detail herein.

[0086] Example 3 was used as the optimal embodiment. A CAK45M-V-6.3V1000F capacitor that had been film-finished and impregnated with graphite was extracted and processed using the method of Example 3. The process flow of bonding, molding, end treatment, rib cutting, aging, aging, high and low temperature screening, measurement, and shaping was then completed according to the process flow. The capacitors were then compared with capacitors of the same model produced using the prior art technology of Comparative Example 1. Except for whether the electronic adhesive impregnation step was performed after the graphite and silver paste, the remaining processes, materials, and equipment were the same. The qualified yields of the two groups of capacitors were calculated, as shown in Table 1. Ten units were randomly sampled from the two groups, numbered accordingly, and placed in the same box for storage at 85°C, 85% RH, and 96 hours. After the storage period, the two groups of products were placed at room temperature for 4 hours, and their electrical performance parameters were tested, as shown in Tables 2 and 3.

[0087] Table 16.3V1000uF-V finished product qualification rate comparison

[0088] Group Finished product qualification rate (%) Comparative Example 1 91.65 Example 3 92.18

[0089] Table 2 Comparison of electrical performance parameters before and after storage of 6.3V1000μF-V produced in Example 3

[0090]

[0091]

[0092] Table 3 Comparison of electrical performance parameters before and after storage of 6.3V1000μF-V produced in comparative example 1

[0093]

[0094]

[0095] A CAK45M-V-100V 10μF capacitor that had been film-finished and impregnated with graphite was extracted and processed using the method of Example 3. The process flow, including bonding, molding, end treatment, rib cutting, aging, aging, high and low temperature screening, measurement, and shaping, was then completed according to the process flow. The capacitors were then compared with capacitors of the same model produced using the prior art technology of Comparative Example 1. Except for the electronic adhesive impregnation step after the graphite and silver paste, the remaining processes, materials, and equipment were identical. The qualified yields of the two groups of capacitors were calculated and shown in Table 4. Ten units were randomly sampled from each group, numbered accordingly, and placed in the same box for storage at 85°C, 85% RH, and 96 hours. After the storage period, the two groups of products were placed at room temperature for 4 hours, and their electrical performance parameters were tested. See Tables 5 and 6.

[0096] Table 4 Comparison of qualified rate of 100V10uF-V finished products

[0097] Group Finished product qualification rate (%) Comparative Example 1 76.28 Example 3 76.84

[0098] Table 5 Comparison of electrical performance parameters before and after storage of 100V10μF-V produced in Example 3

[0099]

[0100]

[0101] Table 6 Comparison of electrical performance parameters before and after storage of 100V10μF-V in Comparative Example 1

[0102]

[0103]

[0104] As can be seen from Tables 1 to 6, the qualified rate of capacitors produced using the process of the present invention is improved, no short circuit occurs during detection, and the overall performance is improved.

Claims

1. A method for improving the stability of tantalum capacitors, characterized by: It includes the impregnation electronic glue process after the impregnation carbon layer process, before the impregnation silver paste process, and after the impregnation silver paste process in the production process of tantalum capacitors.

2. The method for improving the stability of a tantalum capacitor according to claim 1, wherein: The electronic glue impregnation process comprises the following steps: S1: mixing electronic glue and diluent to obtain an impregnating agent; S2: Immersing the tantalum core in an impregnating agent for impregnation treatment; S3: The tantalum core after impregnation is dried.

3. The method for improving the stability of a tantalum capacitor according to claim 2, wherein: The electronic adhesive includes one or more of organic resin, organic silica gel, vulcanized silicone rubber, and epoxy adhesive.

4. The method for improving the stability of a tantalum capacitor according to claim 2, wherein: The diluent includes one or more of toluene, silicone oil, mineral oil, and chlorinated paraffin.

5. The method for improving the stability of a tantalum capacitor according to claim 2, wherein: The immersion treatment includes a first immersion treatment and a second immersion treatment in sequence, and the number of treatments of the first immersion treatment and the second immersion treatment is ≧1.

6. The method for improving the stability of a tantalum capacitor according to claim 5, wherein: The volume ratio of the electronic glue to the diluent in the first dipping treatment is 1:0.5-10.

7. The method for improving the stability of a tantalum capacitor according to claim 5, wherein: The volume ratio of the electronic glue to the diluent in the second dipping treatment is 1:0.5-7.

8. The method for improving the stability of a tantalum capacitor according to claim 5, wherein: In the first and second impregnation treatments, the impregnation and extraction speeds of the tantalum core are controlled to be 1 mm / 1s to 5s to ensure the penetration and filling amount of the electronic glue.

9. The method for improving the stability of a tantalum capacitor according to claim 1, wherein: The drying step includes: dipping the excess electronic glue on the bottom of the tantalum core after the immersion treatment with capacitor paper, placing it at room temperature for 30 minutes to 120 minutes, and then placing it in a drying oven at a constant temperature of 150° C. to 250° C. for 20 minutes to 150 minutes for drying.

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