JPH05246780A - Production of resin-impregnated chip-type electronics parts - Google Patents

Abstract

PURPOSE:To eliminate appearance defects due to resin and to sufficiently hold the amt. of the impregnated resin by successively impregnating by using resin solns. whose concn is stepwise decreased in the process of resin-impregnating a chip-type electronic parts body. CONSTITUTION:A chip-type electronic parts body (e.g. laminated capacitor body) is put into a resin soln. The resin soln. is prepared by mixing a silicon resin (e.g. polymethylsiloxane) and toluene with 3:7 weight ratio. The container of the resin soln. is housed in a sealing chamber which can be evacuated. Then the sealing chamber is evacuated to -600 to -700mmHg reduced pressure and held for about one minute to perform first impregnation. Then the inner pressure of the sealing chamber is made to normal pressure and the raw body in the soln. is taken out. Next, the raw body is put in a resin soln. of silicon resin and toluene with 1:9 weight ratio and treated for second impregnation in the same way as in the first stage. Then third impregnation is performed with a resin soln. having silicon resin to toluene ratio of 1:19. After impregnation, the raw body is taken out from the soln., naturally dried at room temp., and then cured at about 150 deg.C for about 2 hours.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing resin-impregnated chip-shaped electronic parts such as ceramic capacitors.

[0002]

2. Description of the Related Art Chip-shaped electronic parts such as multilayer ceramic capacitors and chip-shaped resistors are often produced as electronic parts to be mounted on a printed circuit board. A monolithic ceramic capacitor is formed by forming internal electrode coatings on each of a plurality of green sheets of ceramic material made of metal oxide such that the ends of the respective green sheets are alternately drawn out in opposite directions. The green sheet on which is formed is laminated and fired to form a capacitor body,
The terminal electrodes are formed on both ends thereof. The chip resistor is a resistor body obtained by forming a resistor film such as a metal film on a ceramic body and forming a protective coating film on the surface thereof, and forming terminal electrodes at both ends of the resistor body. ..

Not only these monolithic ceramic capacitors and chip resistors but also other chip-shaped electronic components, such as a capacitor element body before forming a terminal electrode, and an electronic component element body such as a ceramic material, are ceramic green. When the sheet is made of a fired body, the binder is removed by heating in the manufacturing process, so that the binder remains. Since the porous electronic component element body having a relatively large number of removed portions has low moisture resistance, it may be impregnated with a resin in order to improve the moisture resistance. As the impregnation method, the electronic component element body is put into a resin solution having a constant concentration in which a resin is dissolved in a solvent, and the whole is depressurized. This removes air from the pores in the electronic component body,
After that, the resin solution enters.

[0004]

However, when the electronic component element body is impregnated with resin, dried, and then heat-cured, a resin that cannot completely penetrate into the electronic component element body is formed on the surface thereof. It may adhere. Even if a chip-shaped electronic component of a product is manufactured by using the electronic component base body having a large amount of the adhered amount, the appearance becomes defective, so that the yield of the product is reduced. In order to reduce this appearance defect, the electronic component body can be washed with a solvent without being dried after being impregnated with a resin, but a part of the resin impregnated inside dissolves in the solvent, The original purpose, moisture resistance, cannot be obtained.

An object of the present invention is to provide a method for manufacturing a chip-shaped electronic component in which the resin is sufficiently impregnated and the surface is free of the resin.

[0007]

In order to solve the above problems, the present invention provides a method for manufacturing a chip-shaped electronic component, which comprises a step of impregnating a resin into a chip-shaped electronic component body made of a fired body of a ceramic material. The step of impregnating a chip-shaped electronic component body with a resin provides a method for manufacturing a resin-impregnated chip-shaped electronic component that sequentially uses a plurality of resin solutions in which the resin concentration is gradually reduced.

[0008]

[Function] Since the chip-shaped electronic component element body is impregnated with resin by sequentially using a plurality of resin solutions in which the resin concentration is gradually decreased, if the concentration of the resin solution finally used is lowered,
Even if the resin solution adheres to the surface of the chip-shaped electronic component element body by the first impregnation, this is washed away, and the amount of resin finally adhered decreases, so that the appearance does not deteriorate. Further, since the resin impregnated inside the chip-shaped electronic component body has a lower solubility in the resin solution than in the solvent, the amount of the impregnated resin can be sufficient.

[0009]

EXAMPLES Next, examples of the present invention will be described. Example 1 A ceramic slurry composed of a ceramic material such as a metal oxide and a binder was mixed with polyethylene terephthalate (P
A plurality of ceramic green sheets are prepared by a method of coating on a flat surface such as an ET film), and an electrode material paste made of Pd powder, a binder, etc. is applied to this to form a large number of internal electrode coating films at regular intervals. . Then, the green sheets on which the internal electrode coating films are formed are sequentially stacked so that the ceramic green sheets are sandwiched between the internal electrode coating films, and then the stacked internal electrodes are cut. At this time, only one end of the coating film of the internal electrode is alternately led out to the opposite end face. The individual rectangular parallelepiped laminate thus obtained is fired to obtain a length of 1.6 mm and a width of 0.8 m.
A multilayer capacitor element body as a chip-shaped electronic component element body of m was prepared and used as a test piece.

This test piece was put into a resin solution in which a silicon resin (polymethylsiloxane) and toluene were mixed at a weight ratio of 3: 7, and the container was placed in a depressurizable closed container (for example, a vacuum defoamer). , -600 to -700 mmHg, the first impregnation is performed by holding the pressure reduction degree for about 1 minute. Then, the pressure inside the closed container was returned to normal pressure, the test piece in the solution was taken out, and the silicone resin and toluene were mixed in a weight ratio of 1:
It is added to the resin solution mixed in 9, and the second impregnation is performed in the same manner as described above. Similarly, the third impregnation is performed using a resin solution in which the above silicon resin and toluene are mixed at a weight ratio of 1:19. The test piece impregnated for the third time is taken out of the solution and left to stand at room temperature for 1 hour to be naturally dried. Then, the resin is cured in a dryer at 150 ° C. for 2 hours.

Example 2 In Example 1, a test piece was prepared by carrying out the second impregnation, followed by natural drying and curing at 150 ° C. for 2 hours.

Each of the test pieces of Examples 1 and 2 was 1000
The number of pieces (minimum number required to obtain a defective rate of less than 1%) was prepared, the number of pieces judged to have a defective appearance due to the resin adhering to the surface was counted, and the percentage of the defective appearance (%) to the whole was examined. Shown in 1. Further, for each test piece, an electrode material paste containing Ag-Pd (7: 3) and a binder was attached to both ends of each test piece by a dipping method, dried, and baked to produce a chip-shaped multilayer capacitor in which a terminal electrode was formed. ,
Table 1 shows the results obtained by examining whether or not the quality factor Q is deteriorated (moisture resistance). The test was conducted at 60 ° C for 9
The test was carried out for a sample kept at 5% relative humidity for 500 hours.

Comparative Example 1 In Example 1, a test piece was prepared by performing the first impregnation, followed by natural drying, and curing at 150 ° C. for 2 hours. The results of examining the moisture resistance are shown in Table 1. Comparative Example 2 In Example 1, after the first impregnation, the test piece taken out from the resin solution was washed with toluene for 30 seconds using an ultrasonic cleaner, and dried in the same manner as in Example 1. Table 1 shows the results of examining the defective appearance rate and the moisture resistance of the cured test pieces in the same manner as in Example 1. Comparative Example 3 Example 1 except that the resin solution used when performing the third impregnation of Example 1 was used for each of the three times of Example 1.
Table 2 shows the results of examining the moisture resistance of the test piece impregnated three times in the same manner as in. Comparative Example 4 Table 2 shows the results of examining the moisture resistance of the initial test piece of Example 1 (before impregnation).

[0014]

According to the present invention, since the chip-shaped electronic component element body is impregnated by successively using a plurality of resin solutions in which the resin concentration gradually decreases, even if the resin adheres to the surface of the element-shaped electronic component element, the resin solution becomes thinner. Even if there is little resin left after being washed with the resin solution, the appearance is not bad, and the resin impregnated at the beginning is less likely to dissolve into the resin solution than a simple solvent. Can also hold well.

[Table 1]

Claims (1)

[Claims] 1. In a method for manufacturing a chip-shaped electronic component having a step of impregnating a chip-shaped electronic component element body made of a fired body of a ceramic material with resin, the step of impregnating the chip-shaped electronic component element body with resin A method of manufacturing a resin-impregnated chip-shaped electronic component, which sequentially uses a plurality of resin solutions whose levels are gradually reduced.