KR100909240B1 - Tantalum Capacitor Manufacturing Method - Google Patents

Abstract

The present invention relates to a method of manufacturing a tantalum capacitor to prevent a liquid current defect by going through the reprocessing process.

Tantalum capacitor manufacturing method according to the present invention, a) forming a dielectric layer on the surface of the plurality of pellets to which the anode wire is coupled; b) undergoing a pyrolysis process to form a first cathode layer on the dielectric layers of the plurality of pellet surfaces; c) removing the first cathode layer on the surface of the anode wire by performing a laser trimming process; d) oxidizing the surface of the anode wire from which the first cathode layer is removed by performing a reprocessing process; And e) forming a second cathode layer on the first cathode layer of the plurality of pellet surfaces, thereby oxidizing the surface of the anode wire exposed to the outside, thereby preventing a defect due to liquid current. have.

Description

Manufacturing Method of Tantalum Capacitor

The present invention relates to a tantalum capacitor manufacturing method, more specifically, a liquid current generated by the conduction of the anode wire and the cathode layer by oxidizing the surface of the anode wire exposed to the outside after the laser trimming process. The present invention relates to a tantalum capacitor manufacturing method for preventing defects.

In general, electrolytic capacitors are electronic components used for the purpose of blocking DC current and passing alternating current in addition to a function of accumulating electricity, and the most representative of these electrolytic capacitors is a tantalum capacitor.

Such tantalum capacitors are used in general industrial equipment as well as in application circuits having a low range of rated voltage. In particular, tantalum capacitors are widely used for noise reduction in circuits sensitive to frequency characteristics or in portable communication devices.

Hereinafter, a tantalum production method according to the related art will be briefly described with reference to related drawings.

FIG. 1 is a flowchart sequentially illustrating a method of manufacturing a tantalum capacitor incorporating Teflon, and FIG. 2 is a cross-sectional view of a tantalum capacitor manufactured by the method of FIG. 1.

First and as shown in FIGS. 1 and 2, in the conventional method of manufacturing a tantalum capacitor in which a Teflon 130 is coupled, the anode wire 120 is coupled to each of a plurality of pellets 110 (S10). At this time, the anode wire 120 is a long rod-shaped in the longitudinal direction and one end is fixed to the interior of the pellet (110).

After inserting and coupling the positive electrode 120 to each of the plurality of pellets 110, the Teflon 130 is coupled to the coupling surfaces of the plurality of pellets 110 and the positive electrode 120, respectively (S20). . In this case, the Teflon 130 may be formed in a ring shape in which the central portion thereof is perforated or formed on the bonding surface using a resin.

After coupling the Teflon 130, the other end of the anode wire 120, that is, the opposite side end combined with the pellet 110, is coupled to the plate 100. Then, the dielectric layer 140 is formed on the surface of the plurality of pellets 110 (S30). The dielectric layer 140 is also formed on the surface of the plurality of pellets 110 and a part of the surface of the anode wire 120 connected to the pellets 110.

Next, a pyrolysis process is performed to form a first cathode layer 150 on the surfaces of the plurality of pellets 110 in which the dielectric layer 140 is formed (S40). After completion of the pyrolysis process, a coating process is performed on the first cathode layer 150 to form a second cathode layer 160 (S50).

However, as described above, the tantalum capacitor to which the Teflon 130 is coupled has a limit in miniaturizing the penetration diameter of the Teflon 130 penetrated and coupled to the anode wire 120 as the size of the capacitor gradually decreases. The thickness of the Teflon 130 has a problem of limiting the size of the tantalum capacitor.

In order to solve this problem, a research on a method for manufacturing a tantalum capacitor by removing the Teflon 130 has been conducted, and thus a method of manufacturing a tantalum capacitor will be described with reference to FIGS. 3 and 4 to 6.

FIG. 3 is a flowchart sequentially illustrating a method of manufacturing a tantalum capacitor without using Teflon, and FIGS. 4 to 6 are process cross-sectional views of the tantalum capacitor manufactured by the method of FIG. 3.

As in the method of manufacturing a tantalum capacitor using the Teflon 130, after the anode wire 220 is bonded to the plurality of pellets 210, the dielectric layer 230 is formed on the surface of the plurality of pellets 210 to which the anode wire 220 is coupled. (S110).

After the dielectric layer 230 is formed on the surfaces of the plurality of pellets 210, a pyrolysis process is performed to form a first cathode layer 240 on the dielectric layer 230 (S120). In this case, the pyrolysis process for forming the first cathode layer 240 proceeds only to the plurality of pellets 210, and the first cathode layer 240 is further formed without being formed only up to the plurality of pellets 210. As shown in FIG. 4, the surface of one end of the anode wire 220 is formed.

Then, a laser trimming process is performed to remove the first cathode layer 240 formed on the anode wire 220, and as shown in FIG. 5, only the 'L' region is removed (S130). ). At this time, the reason for leaving the first cathode layer 240 adjacent to the pellet 210 without removing all of the first cathode layer 240 formed on the surface of the anode wire 220 is vibration generated during the laser trimming process. Since the damage may occur in the bonding region of the pellet 210 and the anode wire 220 by overheating, the first cathode layer 240 of the bonding region of the pellet 210 and the anode wire 220 is not removed. .

After completing the laser trimming process, as shown in FIG. 6, a coating process is performed to form a second cathode layer 260 on the first cathode layer 240 formed on the plurality of pellets 210. do.

However, the manufacturing method of the tantalum capacitor according to the prior art as described above has the following problems.

The tantalum capacitor manufactured by the conventional tantalum capacitor manufacturing method not using the Teflon 130 is subjected to a laser trimming process to remove the 'L' region of the first cathode layer 240 by removing the first cathode layer. Although only 240 is to be removed, as shown in FIG. 6, the dielectric layer 230 formed under the first cathode layer 240 is removed together with the first cathode layer 240.

As described above, when the dielectric layer 230 is removed together with the first cathode layer 240 during the laser trimming process, the first cathode is formed by the second cathode layer 250 formed in the coating process as shown in FIG. The layer 240 is brought into contact with the anode wire 220. As a result, the manganese dioxide MnO ₂ of the first cathode layer 240 and the tantalum Ta of the anode wire 220 are bonded to each other. As a result of short circuiting, leakage current (leakage current) failure occurs.

If a liquid current defect occurs, even though the current must not flow to the capacitor's inherent charging capacity, there is a problem that the reliability of the tantalum capacitor is deteriorated as a malfunction occurs due to the current flowing due to the liquid current defect. .

The present invention has been made to solve the above problems, and after the laser trimming process proceeds to the reprocessing process to oxidize the surface of the anode wire exposed to the outside by the liquid current generated by the conduction of the anode wire and the cathode layer (Leakage) It is an object of the present invention to provide a tantalum capacitor manufacturing method for preventing defects.

Tantalum capacitor manufacturing method according to the present invention for achieving the above object comprises the steps of: a) forming a dielectric layer on the surface of a plurality of pellets coupled to the anode wire; b) undergoing a pyrolysis process to form a first cathode layer on the dielectric layers of the plurality of pellet surfaces; c) removing the first cathode layer on the surface of the anode wire by performing a laser trimming process; d) oxidizing the surface of the anode wire from which the first cathode layer is removed by performing a reprocessing process; And e) forming a second cathode layer on the first cathode layer of the plurality of pellet surfaces, thereby oxidizing the surface of the anode wire exposed to the outside, thereby preventing a defect due to liquid current. have.

In this case, the dielectric layer formed in step a) is characterized in that the Ta ₂ O ₅ layer, the first cathode layer formed in the step b) is characterized in that the MnO ₂ layer.

In the step c), the first cathode layer on the surface of the anode wire adjacent to the plurality of pellets is not removed during the laser trimming process, and the anode wire is formed of tantalum.

And, the chemical conversion solution used in the regeneration process in step d) is characterized in that using a solution capable of oxidizing the positive electrode, any one selected from ammonium nitrate, phosphoric acid or ammonium tartrate as the chemical solution It characterized in that to use.

In addition, the reoxidation process oxidizes the surface exposed to the outside of the anode wire by dipping a plurality of pellets in the chemical solution, supplying positive power to the plurality of positive electrode wires, and supplying negative power to the chemical solution. It is characterized by.

At this time, the reprocessing process is characterized in that proceeding at a temperature in the range of 15 ℃ to 80 ℃.

In the tantalum capacitor manufacturing method according to the present invention, after the laser trimming process for removing the first cathode layer formed on the surface of the anode wire proceeds to the reprocessing process to form a dielectric layer by oxidizing the surface of the anode wire exposed to the outside Therefore, there is an effect that can prevent the leakage current (leakage current) caused by the conduction of the anode wire and the first cathode layer.

In addition, the tantalum capacitor formed by the tantalum capacitor manufacturing method according to the present invention can be miniaturized without using Teflon, and has an effect of improving reliability by preventing a liquid current defect.

Details of the tantalum capacitor manufacturing method and the effect thereof according to the present invention will be clearly understood by the following detailed description with reference to the drawings showing preferred embodiments of the present invention.

Example

Hereinafter, a method for manufacturing a tantalum capacitor according to the present invention will be described in detail with reference to the accompanying drawings.

7 is a flowchart sequentially illustrating a method of manufacturing a tantalum capacitor according to the present invention, and FIGS. 8 to 12 are process cross-sectional views illustrating a method of manufacturing a tantalum capacitor according to the present invention.

First, in the method of manufacturing a tantalum capacitor according to the present invention, as illustrated in FIGS. 7 and 8, the anode wire 420 is inserted into one end of each of the plurality of pellets 410 by a predetermined depth to be coupled thereto. In this case, each of the plurality of pellets 410 is formed through a molding and sintering process using tantalum powder (not shown), and the anode wire 420 also forms the pellets 410. It is formed into a rod shape using powder.

After bonding the anode wire 420 to each of the plurality of pellets 410, the other end of the anode wire 420 is bonded to a plate 400 made of a conductive material. The reason why the anode wire 420 is bonded to the plate 400 is that the dielectric layer 430 and the first and second cathode layers are formed on the surfaces of the plurality of pellets 410 and the anode wire 420 during the process described below. When forming the 440 and 450, each of the pellets 410 may be formed on the plurality of pellets 410 without separately forming the dielectric layer 430 and the first and second cathode layers 440 and 450. In order to simultaneously form layers, the anode wires 420 connected to the plurality of pellets 410 are bonded to the plate 400. Accordingly, there is an advantage in that the process for forming the dielectric layer 430 and the first and second cathode layers 440 and 450 can be shortened.

Then, a chemical conversion process is performed to form the dielectric layer 430 on the surface of the plurality of pellets 410 to which the anode wires 420 are coupled (S310). The dielectric layer 430 is formed to insulate the pellet 410 from the first cathode layer 440, and the chemical conversion process is performed by the anode wire 420 having the dielectric layer 430 coupled to the pellet 410. Form up to 1/3 or 1/2 point.

The reason why the dielectric layer 430 is formed to a part of the anode wire 420 coupled to the pellet 410 is that the first and second cathodes are formed when the first and second cathode layers 440 and 450 described later are formed. The layers 440 and 450 are not formed only on the pellet 410, but are formed up to a part of the anode wire 420 so that the anode wire 420 is brought into contact with the first and second cathode layers 440 and 450. The dielectric layer 430 is formed on a part of the surface of the anode wire 420 that is coupled to one end surface of the pellet 410 in order to prevent the occurrence of short. In addition, the dielectric layer 430 formed by the chemical conversion process is preferably formed of a Ta ₂ O ₅ layer.

After forming the dielectric layers 430 on the surfaces of the plurality of pellets 410 and the anode wires 420 through the chemical conversion process, a pyrolysis process is performed to form the dielectric layers 430 on the surfaces of the plurality of pellets 410. ) To form a first cathode layer 440 (S320). At this time, the first cathode layer 440 formed by the pyrolysis process is characterized in that the manganese dioxide (MnO ₂ ), the pyrolysis process proceeds so that the first cathode layer 440 is formed to the surface of the pellet 410 do.

At this time, when the pyrolysis process is stopped when the first cathode layer 440 is formed to the surface of the pellet 410, the first cathode layer 440 is not formed only up to the surface of the pellet 410, but the anode wire 420. It is formed up to a part of the surface of the dielectric layer 430 formed on). In this way, a laser trimming process is performed to remove the first cathode layer 440 formed on the surface of the dielectric layer 430 on the anode wire 420.

The laser trimming process removes the first cathode layer 440 formed in the region “D”. In this case, the reason for leaving the first cathode layer 440 adjacent to the pellet 410 without removing all of the first cathode layer 440 formed on the anode wire 420 may occur during the laser trimming process. A portion of the first cathode layer 440 adjacent to the pellet 410 is left to prevent vibration and heat from being transferred to the pellet 410.

Particularly, when the first cathode layer 440 is removed by the laser trimming process, only the first cathode layer 440 is not removed. As shown in FIG. 9, the first cathode layer of the region “D” is shown. The dielectric layer 430 formed therein is also removed along with the first cathode layer 440. When the dielectric layer 430 is removed as described above, the first cathode layer 440 and the anode wire 420 come into contact with each other by the second cathode layer 450 when the second cathode layer 450 is to be described later.

In this case, since the first cathode layer 440 is made of manganese dioxide (MnO ₂ ), when the first cathode layer 440 is combined with the anode wire 420 made of tantalum, a short occurs in the bonded region, thereby generating a liquid current. Can be.

In order to prevent this, the tantalum capacitor according to the present invention performs a reformation process for oxidizing the exposed surface of the anode wire 420 after the laser trimming process (S340).

As shown in FIG. 10, the plurality of pellets 410 in the chemical solution S may be formed by adjoining the plate 400 in which the plurality of pellets 410 are coupled to the container 402. Deeping. In this case, the plurality of pellets 410 and the exposed surfaces of the anode wire 420 are dipped in the recyclable solution S, and the plate 400 connected to the plurality of anode wires 420 is positive (+). After supplying power and supplying negative (-) power to the chemical solution (S) through the conductor 401, the process of regenerating is maintained by maintaining a constant temperature.

In particular, the chemical conversion solution may be a solution capable of oxidizing the positive electrode wire 420. The chemical conversion solution may be any one selected from ammonium nitrate, phosphoric acid, or ammonium tartrate.

In addition, the reprocessing process proceeds at a temperature in the range of 15 ° C to 80 ° C, the reason for proceeding the regeneration process in the range of 15 ° C to 80 ° C, when the process progress temperature is 15 ° C or less the chemical solution (S) Since the activation of ions is low, it is difficult for the oxidation process to proceed on the surface of the anode wire 420. When the process progress temperature is 80 ° C or higher, the activation of the chemical solution (S) ions is too high, so that the oxidation of the user desired thickness is progressed. Therefore, it is preferable to proceed with the recyclability process at a temperature in the range of 15 ° C to 80 ° C.

In this case, the time for performing the reprocessing process is determined according to the progress temperature and the oxidation thickness of the reprocessing process. For example, if the surface of the anode wire 420 is oxidized at a desired thickness for 30 minutes at 20 ° C, it is preferable to oxidize the surface of the anode wire 420 by proceeding at 50 ° C for 20 minutes.

As shown in FIG. 11, the anode wire 420 is oxidized in the “D” region and the coating process is performed on the plurality of pellets 410, as shown in FIG. 11. As described above, a second cathode layer 450 is formed on the first cathode layer 440 (S350).

At this time, the second negative electrode layer 450 is formed of two layers. First, a carbon layer is formed, and then the carbon layer is preferably coated with silver (Ag). The first and second cathode layers 440 and 450 thus formed become cathodes (-) and the anode wires 420 become anodes (+) to complete a tantalum capacitor.

The improvement of the poor liquid current of the tantalum capacitor formed by the capacitor manufacturing method according to the present invention will be described with reference to the following [Table 1] and FIG.

13 is a defective current rate of the tantalum capacitor which is supplied with power and the regeneration process is carried out in a 25 ° C. chemical solution, and T is a value of the tantalum capacitor that is refired in a 25 ° C. chemical solution without power. The liquid current defective rate is H, and H represents the liquid current defective rate of the tantalum capacitor which has been reprocessed in a 70 ° C. chemical solution without supplying power.

As shown in [Table 1] and FIG. 13, when power is supplied from the chemical solution at 25 ° C. to proceed with the regeneration process, 39.0 is less than 52.5% of the liquid current defective rate when the regeneration process is not performed. % Defective rate is 13/6%.

On the other hand, if the regeneration process is performed without supplying power in the same chemical solution at 25 ° C., only 5.0% of the liquid current defect rate without the regeneration process is improved, and the chemical solution at 70 ° C. If the reprocessing process is performed without supplying power to the system, only 1.7% improvement is achieved over the liquid current defective rate when the reprocessing process is not performed.

Accordingly, it can be seen that when the temperature of the chemical solution is maintained at 15 ° C. to 80 ° C. and the power is supplied, the defect rate caused by the liquid current of 39.0% can be reduced.

As described above, the tantalum capacitor formed by the tantalum capacitor manufacturing method according to the present invention undergoes a reprocessing process for oxidizing the exposed surface of the anode wire 420 after the laser trimming process. Preventing conduction of the layer 440 has the advantage of preventing the generation of liquid current.

In addition, by preventing the generation of the liquid current generated in the anode wire 420 and the first cathode layer 440, the defect of the tantalum capacitor according to the present invention can be reduced, thereby improving reliability. .

Preferred embodiments of the present invention described above are disclosed for the purpose of illustration, and various substitutions, modifications, and changes within the scope without departing from the spirit of the present invention for those skilled in the art to which the present invention pertains. It will be possible, and such substitutions, changes and the like should be regarded as belonging to the following claims.

1 is a flow chart sequentially showing a manufacturing method of a conventional tantalum capacitor coupled to Teflon.

2 is a cross-sectional view of a tantalum capacitor manufactured by the manufacturing method of FIG.

Figure 3 is a flow chart sequentially showing a manufacturing method of a conventional tantalum capacitor without using Teflon.

4 to 6 are cross-sectional views of tantalum capacitors manufactured by the manufacturing method of FIG. 3.

7 is a flowchart sequentially showing a method of manufacturing a tantalum capacitor according to the present invention.

8 to 12 is a cross-sectional view showing a method of manufacturing a tantalum capacitor according to the present invention.

Figure 13 is a graph showing the liquid phase defect ratio according to the reprocessing process.

<Description of Symbols for Major Parts of Drawings>

400: plate 401: conductor

402 container 410 pellet

420: anode wire 430: dielectric layer

440: first cathode layer 450: second cathode layer

S: chemical solution

Claims (9)

a) forming a dielectric layer on a plurality of pellet surfaces to which the anode wires are coupled; b) undergoing a pyrolysis process to form a first cathode layer on the dielectric layers of the plurality of pellet surfaces; c) removing the first cathode layer on the surface of the anode wire by performing a laser trimming process; d) oxidizing the surface of the anode wire from which the first cathode layer is removed by performing a reprocessing process using a chemical solution capable of oxidizing the anode wire; And e) forming a second cathode layer on the first cathode layer of the plurality of pellet surfaces; Tantalum capacitor manufacturing method comprising a. The method of claim 1, Method of manufacturing a tantalum capacitor, characterized in that the dielectric layer formed in step a) is a Ta ₂ O ₅ layer. The method of claim 1, Tantalum capacitor manufacturing method, characterized in that the first cathode layer formed in step b) is a MnO ₂ layer. The method of claim 1, And c) removing the first cathode layer on the surface of the anode wire adjacent to the plurality of pellets during the laser trimming process in step c). The method of claim 1, The anode wire is a tantalum capacitor manufacturing method characterized in that formed of tantalum (tantalum). delete The method of claim 1, Tantalum capacitor manufacturing method characterized in that using any one selected from ammonium nitrate, phosphoric acid or ammonium tartrate as the chemical solution. The method of claim 1, In the reoxidation process, after dipping a plurality of pellets in the chemical solution, a positive power is supplied to a plurality of positive electrode wires and a negative power is supplied to the chemical solution to oxidize a surface exposed to the outside of the positive electrode wire. Tantalum capacitor manufacturing method characterized in that. The method of claim 1, The reprocessing process is a tantalum capacitor manufacturing method, characterized in that proceeding at a temperature in the range of 15 ℃ to 80 ℃.

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