JPH01236636A - Mounting process of electronic component - Google Patents

Abstract

PURPOSE:To simplify the mounting process by a method wherein the substrate of an electronic component and a wiring substrate are fixed with a thermoplastic resin of a melting point lower than that of solder bumps and then the electronic component and the wiring substrate are heated at a temperature higher than the melting point of the solder bumps to connect the electronic component with the wiring substrate. CONSTITUTION:A substrate 2 of an electronic component 1 and a wiring substrate 8 are fixed by a thermoplastic resin 15 in lower melting point than that of solder bumps 11a, 11b in the state where the solder bumps 11a, 11b formed on the electronic component 1 are brought into contact with the input terminals 10a, 10b of the wiring substrate 8 and then the electronic component 1 and the wiring substrate 8 are heated at the temperature higher than the melting point of the solder bumps 11a, 11b to connect the electronic component 1 with the wiring substrate 8. The softened thermoplastic resin 15 enters into the gap between the electronic component 1 and the wiring substrate 8 not to decrease said gap exceeding the required amount while the thermoplastic resin 15 sets to become a reinforcement when the heating process is terminated thus eliminating any later reinforcing process. Through these procedures, the mounting process can be simplified.

Description

Detailed Description of the Invention G(J Industrial Field of Application) The present invention is a photoelectric conversion device that converts optical signals into electrical signals and converts optical energy into electrical energy. This invention relates to a method for attaching electronic components to a bag.

(l:+) Conventional technology A film-containing electrical converter and the light! A light wire with a plurality of output terminals for deriving the photoelectric conversion output of the converter [conversion element is 1, for example, Japanese Patent Publication No. 5 B-2182
No. 7 discloses an example of application to solar cells, and
Applications to various applications have already been attempted, as an example of application to an optical sensor is described in Japanese Patent No. 31585.

When putting these photoelectric conversion elements into practical use, the surrounding [
With gc circuit? ! In addition to electrical connection, mechanical fixing is also required.

Solder on the connection terminals of electronic components such as ICs? (It is possible to increase the mounting density of electronic components, which form an electrical connection with the wiring board and thereby make an electrical connection with the wiring board, compared to the method of making electrical connections by wire bonding. In recent years, the number of fields using this mounting method has increased because it requires less time.

An example of a conventional mounting method for electronic components is shown in FIGS. 7 to 7. Figures 7 to 10 are cross-sectional views showing the mounting process in order.

In these figures, (8) is made of ceramic or glass epoxy and has arbitrary wiring t! on one surface. (9B) (
9b), (1) is an electronic component such as an optical sensor, (Ilj) (llb) is a solder bump formed on the connection terminal part of the electronic component Lυ, and ■ is the electronic component tl before the bag layer.
] Fixing jig for fixing wiring board (8)K, (21
1 is a space interposed between the electronic component (1) and the wiring board (8), and @ is a reinforcing material filled between the electronic component (1) and the wiring board (8) after mounting.

As shown in No. 7-, the solder pan 1 (1) of the electronic component 11)
11(llb) to the wiring 11Ac 91L on the board ζ8)
)C9b)O Align with the prescribed portions (10a) (10b) and fix with the fixing jig (■). At this time, 1wL child part (1
) and the board (8) by the KH fixing jig (to) K. Then, as shown in the MB diagram, the solder bumps (In) (Ill)) are heated to a temperature higher than their melting point. do. Through this heat treatment, the solder bumps (Ill) (llb) are melted, and the distance between the electronic component (1) and the board (8) is reduced due to the stress from the fixing jig (■), and the gap between the electronic component opening 1 and the board (8) is reduced.
The wiring location (10a) (Job) is solder bump C11a
) (llb) t-suke L't”!
Continue.

Thereafter, as shown in FIG. 9, I&temporary (8) is returned to room temperature, and fixing jig (3) and space fclJ are removed.

Then, in this state, the wiring (
9JL) (9b) and! Although the electrical connections are complete, the physical strength is insufficient. Therefore, as shown in FIG. 10, a thermosetting resin such as epoxy resin III or a silicon-based reinforcing material is filled between the electronic component (1) and the substrate (8).

Problems to be Solved by the Invention In the above-mentioned handling method using solder bumps, there are the following steps: fixing the electronic component (1) at a predetermined position on the mounting Rti and the plate (8); When KW1 child parts (υ and wiring board (
87 decreases, and does not decrease to K by more than a certain distance.

Cl11) Must have sufficient strength after installation.

is required.

For this reason, in the past, it was necessary to use appropriate fixing jigs and spacers, and it was also necessary to fill in the reinforcing material after attachment, making the process cumbersome.

B.) Means for Solving the Problems The present invention provides an electronic component in which solder bumps are formed on terminal portions provided on one surface of a board, and an electronic component having input terminals corresponding to the terminal portions. 11. This is a method for attaching electronic components to a printed wiring board.

With the solder bumps formed on the front 11i3 electronic component in contact with the input terminals of the wiring board, the board of the electronic component and the wiring board are fixed with a hot plastic resin having a melting point lower than that of the solder bumps, and then the The electronic component and the wiring board are heated to a temperature higher than the melting point of the solder bump, and the electronic component and the wiring board are heated! It is characterized by continuing.

(e) Effect When the fixed f'L9 electronic component wire board is heated.

As the thermoplastic resin softens, the solder bumps melt, reducing the distance between the electronic component and the wiring board. And softening,
The heated thermoplastic resin will infiltrate between the electronic components and the wiring board, so the distance between the electronic components and the wiring board will not be reduced more than necessary, and the thermoplastic resin will harden and become a reinforcing material when heating is finished. There is no need to perform correction #jJ in the subsequent process.

(F) Embodiment Hereinafter, an embodiment in which the present invention is applied to an optical sensor will be described with reference to FIGS.

FIG. 1 shows a state in which an electronic component according to the present invention is being installed, and (1) is a photoelectric conversion element, which is a translucent insulator such as glass. i[(23 on the single part (211), anO21
The first material (3), which is made of a translucent conductive oxide, such as TO, etc. pln junction parallel to the a-plane.

For example, a film thickness of 4°00 having a semiconductor junction such as a p-n junction
jt1 consisting of a semiconductor film (4) mainly composed of amorphous silicon of λ~xpms degree and a metal such as aluminum
A film-like optical WK converter (6) with a film thickness on the order of a chip micron to a micron, which is composed of a product of two-charged films (polar films), is provided, and the optical WK converter (6) is F is the above tR1/2nd insulating substrate (2) from the polar film (3],
] single part (2a) KW, t, 7F, extended part (3;
, t5i upper ttc42 seven punishments old 6 gold, silver IJ
Output terminal (7a) made of heat-cured conductive paste made by mixing metal powder such as epoxy or phenol into resin,
Derived from (7b). (8) is any wiring (9a)
, (9b), and the wiring board in the present invention includes a printed MA board made of ordinary glass epoxy, a flexible wiring board made of polymeric materials such as polyester and polyimide, and a lead frame, etc. including.

(10a) and (10b) are input terminals provided integrally with specific wirings (9a) and (9b) of the wiring board (8),
Output terminal (71 (7
It corresponds to b).

C1l&)(llb) is such a light 'vlt conversion element (11
The melting point of the light converting element (1) or the wiring board (8) is pre-wired on the output terminal of the
It is made of a material with a low melting point that will not cause any damage to the groove bottom element. In this example, a bismuth-based low melting point solder having a melting point of about 135° C. was used.

In addition, the above-mentioned arrangement M & board (8) arrangement M (9a) (9t))
It is made of copper plated with solder plating.

Now, the output terminal (7a) of the above-mentioned photoelectric conversion element (1)
7b] semiconductor bumps (Ill) (llb) f, a predetermined portion of the wiring on the wiring board (8), that is, the input terminal (10
a) According to (10b), fix the substrate (2) of the photoelectric conversion element (1) to the wiring board (8) using thermoplastic resin u9. Thermoplastic resin (151 is ethylene vinyl acetate polyamide with a softening point of about 95°C, polyglopylene,
Using a polyethylene-based resin, it can be discharged in liquid form from the iπ-Kyo nozzle, and applied to predetermined parts of the photoelectric conversion element (IJ's insulating board (2) and wiring board (8)). Both are fixed as shown. Fig. 2 is a plan view showing the next state after the thermoplastic resin U31t is layered in this manner.

Subsequently, the substrate (8) on which the optical Vt conversion element 11) is fixed is heated. In the case of the aforementioned solder bump (111 (llb)) and thermal ffi resin A9, good layer deposition can be achieved by using vapor phase soldering (hereinafter referred to as VPS 1) at about 155°C. When the wiring board (8) on which the photoelectric conversion element (1) is fixed is inserted into the saturated vapor phase obtained by heating the inert organic solvent in a wood and bringing the liquid to a boil, the vapor flows onto the board. This latent heat causes the temperature of the substrate to rise rapidly and uniformly in the total vapor temperature range, and the half H1 and thermoplastic resins are melted.

FIG. 5 shows the next state in which the solder bump (lla) (11b) and the thermoplastic resin ttS are melted by heating.

Due to the difference in their melting points and softening points, we first choose thermoplastic resins (
151 softening occurs prior to melting of the solder bump (lla) (lit). Softened thermoplastic resin (151
enters between the photoelectric conversion element (1) and the wiring board (8), and a stress is generated that tends to pull the photoelectric conversion element (1) together with the substrate (2) toward the wiring board (8).

As mentioned above, heating by V P, S K causes a rapid temperature rise, so the solder bump (111 (1 lb)
1111) (llb) melted and the input terminals (10a) (10b) and the melted solder bumps (Ill
You will have an emotional connection with (llfi).

As shown in FIGS. 5 and 6, the softened thermoplastic resin uS melts, surrounds the solder bumps (Ill) (ilb), and further penetrates into the interior. The distance between the optical Ti conversion element (1) and the substrate (8) is not reduced more than necessary because of the presence of the thermoplastic resin σ9 in between, and the distance between the solder bumps (Ill) (llb) and the entire island of the plastic resin tlS Since the solder bumps (Ill) (Ilb) are surrounded by the solder bumps (Ill) (Ilb), there is no need to worry about them spreading and causing a short circuit between the adjacent ff1T wiring (9a) (9t)) or the solder bumps (Ill) (llb).

When the temperature is returned to normal in this state, solder bumps (Ill) (1l
b) Photoelectric conversion element (11 and arrangement, 11 (8) is electric C
The n% island is cured into a plastic resin RI9, and becomes a reinforcing material that increases the physical strength of the connection between the photoelectric conversion element (II) and the wiring board (8).

(G) As described in detail, according to the present invention, there is no need for special jigs or benches, and there is no need to form reinforcing materials as a post-process, which simplifies the installation process. At the same time, the parts can be reliably attached to the wiring board.

[Brief explanation of the drawing]

Figures 1 to 6 show an embodiment of the invention,
FIG. 1 is a perspective view showing a state in the middle of installation. FIG. 2 is a plan view showing a state in which an electronic component and a wiring board are fixed with thermoplastic resin, FIG. 3 is a plan view showing a state in which an electronic component is attached to a wiring board according to the present invention, and FIGS. 6 is a sectional view corresponding to the section taken along the line X--X in FIG. 1 for sequentially explaining the mounting process. 7 to 10 are cross-sectional views for sequentially explaining the conventional mounting process. l... Photoelectric conversion element (electronic component), 2... Insulating substrate, 8... Distribution, 11 board%9a, 9b-wiring, 10jL
, 10b'...input terminal, lla, llb...solder bump.

Claims (1)

[Claims] (1) Mounting of an electronic component, in which an electronic component having solder bumps formed on a terminal section provided on one main surface of the board is attached to a wiring board with wiring provided with an input terminal corresponding to the terminal section. The method includes fixing the electronic component substrate and the wiring board with a thermoplastic resin having a melting point lower than that of the solder bumps, with the solder bumps formed on the electronic component in contact with the input terminals of the wiring board. After that, the electronic component and the wiring board are heated to a temperature higher than the melting point of the solder bump to connect the electronic component and the wiring board.