JPH0468596A - Method of mounting electronic parts - Google Patents

Abstract

PURPOSE:To mount it on the surface without shorting the electrodes of chip parts mutually by temporarily fixing the electrode of a chip part once on the prepreg tape which is impregnated, between conductive resin adhesives, with insulating resin, and then placing them on the land of a circuit board, and heating and hardening the conductive resin adhesive so as to bond them together conductively. CONSTITUTION:This describes the case of mounting a chip capacitor on a circuit board. First, the chip capacitor 1 is placed on a pregpreg tape 2. Next, both ends are turned up to fit the side faces of both electrodes 1a of the chip capacitor 1, and by stickiness of the conductive resin adhesive 2b, it is stuck. Next, it is placed on the land 3a of the circuit board 3, and is temporarily fixed. Next, a prepreg tape 2 is heated, and hardened in the condition that the conductive resin adhesive 2b oozes out of the prepreg tape 2 a little and forms a resin fillet 2b-1, thus the chip capacitor 1 is fixed regularly to the circuit board 3.

Description

[Detailed Description of the Invention] [Summary] This invention relates to a method for mounting electronic components, and in particular to a method for surface mounting chip components on a circuit board. Once the electrodes of the chip component are placed on a prepreg tube formed by impregnating a cloth or non-woven fabric with a conductive resin adhesive having adhesiveness corresponding to the electrodes of the chip component, and impregnating an insulating resin between the conductive resin adhesives, After being temporarily fixed, the circuit board is placed on the land of the circuit board, and the conductive resin adhesive is heated and cured to conductively bond the circuit board.

[Industrial application field]

The present invention relates to a method for mounting electronic components, and more particularly to a method for surface mounting chip components on a circuit board.

When surface mounting chip components (micro components) on a circuit board, conductive resin adhesive is used as a bonding material instead of solder cream to avoid cleaning after soldering, but short circuits between electrodes due to protrusion occur. There is a need for a mounting method that eliminates short-circuit defects.

[Prior Art] Conventionally, as shown in the exploded perspective view of FIG.
Dispenser (
Apply an appropriate amount of conductive resin adhesive 12 such as silver-epoxy resin using a method (as shown in the figure), place a chip component 11 such as a chip capacitor thereon, and press the picture electrode 11a onto it.
The conductive resin adhesive 12 is heat-cured and mounted.

[Problem to be solved by the invention] However, according to the above-mentioned mounting method, the seventh
As shown in the side cross-sectional view showing a short-circuited state in the figure, there was a problem in that the conductive resin adhesive that overflowed when the chip component was pressed caused a short circuit between the electrodes of the chip component. Therefore, there is a method of placing the chip capacitor on the land first and then applying conductive resin adhesive on both sides of the electrode with a dispenser and bonding it. However, this method does not adhere sufficiently to the bottom of the chip capacitor, so the bonding area There is a problem that the adhesive strength is not sufficient.

In view of the above-mentioned problems, an object of the present invention is to provide a method for mounting an electronic component that can be surface-mounted without shorting between the electrodes of a chip component.

[Means for Solving the Problems] In order to achieve the above object, in the electronic component mounting method of the present invention, the woven fabric or nonwoven fabric has adhesiveness corresponding to the electrodes of the chip component! I After temporarily fixing the electrodes of the chip components onto a prepreg tape impregnated with a conductive resin adhesive and with an insulating resin impregnated between the conductive resin adhesives, the electrodes of the chip components are placed on the lands of the circuit board and the The conductive resin adhesive is heated and cured to form a conductive bond.

[Function] Since an electrically insulating band is formed in the central part of the prepreg tape using an insulating resin, it acts as a separating wall between the conductive resin adhesives and can prevent short circuits.

〔Example〕

The gist of the present invention will be explained in detail below based on embodiments shown in the drawings.

As shown in the side sectional view of FIG. 1, a chip component 1, for example a chip capacitor, is mounted by adhesively mounting it on a land 3a of a circuit board 3 using a prepreg tape 2. As shown in the perspective view of FIG. 2, this prepreg chive 2 consists of a nonwoven fabric 2a (or woven fabric) made of glass fiber, polyester fiber, or polyamide fiber, and each end is made of silver or copper having adhesive properties corresponding to the electrodes of the chip component. , is impregnated with a conductive resin adhesive 2b such as an epoxy resin containing a highly conductive metal powder such as aluminum or carbon powder, and an insulating resin 2c such as an epoxy resin is applied between the double-door conductive resin adhesive 2b.
impregnated and produced.

For example, when a chip capacitor is mounted on a circuit board using this prepreg tape, Figures 3(a) to (
This will be explained using the side sectional view of d).

In FIG. 3(a), a chip capacitor 1 is placed on a prepreg tape 2.

In FIG. 3(b), both ends of the prepreg tape 2 are bent and wrapped around the side surfaces of the picture electrode 1a of the chip capacitor 1, and adhered by the adhesiveness of the conductive resin adhesive 2b.

In FIG. 3(C), it is the land 3a of the circuit board 3.
Place it on top and temporarily fix it.

In FIG. 3(d), the prepreg tape 2 is heated,
A small amount of the conductive resin adhesive 2b is removed from the prepreg tape 2.
2b-1 is cured to the formed state, and the chip capacitor 1 is formally fixed to the circuit board 3.

In this way, since the conductive resin adhesive impregnated into the prepreg tape has adhesive properties, once it is attached to the chip component, it can be temporarily fixed to the runt of the circuit board without shifting. In addition, the central part of the prepreg tape is blocked by forming an insulating band with insulating resin impregnated into the nonwoven fabric itself.
Since the electrodes are bonded by a slightly small amount of the conductive resin adhesive seeping out, short circuits between the electrodes due to the conductive resin adhesive will not occur.

Next, other embodiments mass-produced in large numbers will be described using perspective views and side views of FIGS. 4(a) to 4(C).

As shown in FIG. 4(a), the prepreg tape 2, that is, 2-
1 is formed into a long tape in multiple pieces, and as shown in No. 4M(b), it is cut with a cutter (path shown) to a predetermined length according to the chip capacitor 1 to be connected.

Then, chip capacitors 1 are placed one by one on the cut prepreg chip 21a.

Next, as shown in FIG. 4(C), to wrap the U-shaped cross section, push it into the groove 48 of the tool 4 using the presser bar 5.
Both ends of the small piece of prepreg tape 2-1a are bent and wrapped around the side surface of the picture electrode 1a, and attached using the adhesiveness of the conductive resin adhesive 2b. The following steps are the same as those shown in Figure 3 (C1 and below) to formally fix the microcapacitor to the circuit board.

As shown in FIG. 4, by making the prepreg chive into a long tape, it is possible to cut a large number of pieces and achieve mass production.

The amount of conductive resin adhesive seeping out from the prepreg tube is controlled by the amount of conductive resin adhesive impregnated into the prepreg tape at the time of tape production. As shown in the side sectional view of FIG. 5, conductive resin adhesive 2b-2 can be additionally applied to both sides of the electrode 1a using a dispenser (path shown) to strengthen the adhesion.

〔Effect of the invention〕

As described in detail above, according to the present invention, it is possible to prevent short circuits between the electrodes of chip components, and there is no misalignment of the chip component with respect to the land, and the adhesive strength can be strengthened as necessary, so that the connection can be improved. It has extremely useful effects in industry, such as improving reliability and increasing productivity by using multiple tapes.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing the mounting state of one embodiment of the present invention, FIG. 2 is a perspective view of the prepreg tape used in FIG. 1, and FIGS. 3(a) to (d) are 4(a) to 4(C) are perspective views and side views of other embodiments according to the present invention; FIG. 5 is a side sectional view showing the mounting method in the order of steps; FIG. Side sectional view, No. 6
The figure is an exploded perspective view according to the prior art, and FIG. 7 is a side sectional view showing the short-circuited state of FIG. 6. In the figure, l is a chip component (chip capacitor), 1a is an electrode, 2 is a prepreg tape, 2a is a nonwoven fabric (woven fabric), 2b is a conductive resin adhesive, 2c is an insulating resin, 3 is a circuit board, 3a is a Each land is shown. Agent Patent Attorney Sada Igata −! -r. and I-7 Pa.X? 4J] = (↓ Prepreg Chive 2 Daiku Daiku

Claims (1)

[Claims] A conductive resin adhesive (with adhesiveness corresponding to the electrodes (1a) of the chip component (1)) is applied to the woven or nonwoven fabric (2a).
The electrode (1a) of the chip component (1) was temporarily fixed onto a prepreg tape (2) impregnated with the conductive resin adhesive (2b) and an insulating resin (2c) between the conductive resin adhesive (2b). A method of mounting an electronic component, characterized in that the circuit board (3) is then placed on the land (3a) and the conductive resin adhesive (2b) is heated and cured to conductively bond it.