JPS61208893A - Soldering - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a soldering method.

[Technical Background of the Invention and Problems Therewith] As a method for soldering electronic components with leads, for example, in a predetermined position on a four-way flat package ICt-printed circuit board, a method for soldering the electronic component with a lead in a predetermined position on a conventional Ct-printed circuit board is used. There is a method of performing 970-soldering by irradiating the IJ-board with a laser beam.

However, when a four-way flat package is mounted using this method, electrical connection failures occur frequently and the yield is low.

A detailed investigation of this poor connection revealed that it had deformed into a printed circuit, and due to this deformation, gaps were created between the solder joints in some places, causing electrical connection defects in these gaps. I understand that.

This phenomenon manifests itself prominently in automation. In order to improve productivity, self-propelled products are required to become faster and faster, and there is a problem that the higher the speed, the more the above-mentioned defects occur.

[Purpose of the invention]

The present invention has been made in view of the above points, and it is an object of the present invention to provide a soldering method that enables highly reliable soldering in automation and improves yield through high-speed mounting.

[Summary of the invention]

That is, when transferring a plurality of electronic components with leads and automatically soldering the lead portions, a step of temporarily fixing the electronic components by spot heating at least one lead after transferring the electronic components to a soldering position. and a step of sequentially spot-heating and scanningly soldering the soldered portions of the temporarily fixed electronic component leads.

[Embodiments of the invention]

Next, we will show a drawing showing an example of soldering a leaded electronic component, for example, a four-way flat package (1) having a large number of leads on four sides, to the soldering position of a printed wiring board (2). Refer to and explain. A four-way flat bag (1) shown in the first section is installed in a stocker (not shown) configured to be stored in each compartment according to a predetermined order. A mounting head (
3) is held and transported. That is, it is vacuum chucked by a collet (4) provided on the head (3), transported to a positioning position (not shown), and placed on a positioning table. At this positioning position, for example, the four sides of the package portion (5) of the flat package (1) are narrowly attached and positioned. For example, patent application 5% -/7.
The technology of No. 33'B is fine. Of course, other positioning means may be used.For example, Japanese Patent Application Sho S'j-15875
After positioning, the center part (6) of the package (5) is again chucked by the collet (4), and the bonding is carried out from the magazine (not shown). Place the printed circuit board (2) at the soldering position which has been transported to the soldering position. At the same time or after this placement, the above collet (4)
According to the state of the Baquième chuck, the flat package (1) is pressed with a moderate pressure, and a part of the flat package (1) is glued (for example, one lead (7) on each of the two opposing sides). Soldering position (8)
(9)? Heat and solder in spots. That is, it is temporarily attached. This means may, for example, be irradiated and soldered in a sequential manner. This is a collet (
4) It is soldered in a fixed state. After the solder hardens in this soldering process, the suction of the collet (4) is stopped and the collet (4) is transferred to the stocker position. At the same time as the collet (4) is transferred, the laser optical system α
Or move the housing υ and the printed circuit board (2) relatively,
Figure 1 shows the lead (7) of the four-way flat package (1). (1
) and conductive pattern (1) on IJ flow solder. This laser beam αa is irradiated onto the entire laser soldered portion by raising the mounting head (3) in a larger area than the spot at the time of temporary fixing.

This scanning soldering is done by collet (
4) Because the temporary fixing is carried out in a firmly fixed state, electrical connection defects caused by scanning soldering can be significantly reduced.

This scanning soldering was explained as an example in which it was performed using only one laser optical system as shown in the opening of Figure 1, but by powering up the laser source (not shown) and simultaneously using the laser optical system (IIQD). In this case, the scanning becomes L-shaped and has the effect of completing soldering in half the time.The laser optical system α (eαυ is the laser source, e.g., the YAG laser output light is guided through the optical fiber ttS. What is necessary is to configure the laser terminal to focus the light on the soldering part through a focusing lens.

It is sufficient that the laser optical system αIαυ is moved relative to the printed circuit board (2), but only the laser optical system (II (11)) may be moved.At this time, the laser optical system is attached to the side wall of the mounting head (3). It is sufficient to provide a moving guide of H(lυ) and control this guide to move intermittently.

The timing and programs for each process of the mounting head (3), cholera (4), and printed circuit board (2) are all created in advance, input into a computer, and controlled centrally by the computer.

Furthermore, in the above embodiments, spot heating was performed using a gold laser beam, but any means that can selectively adjust the temperature required for soldering may be used.9 For example, infrared spot irradiation or high frequency heating may be used. Anything is fine.

Furthermore, in the above embodiment, the scanning soldering after temporary fixing was performed from the temporary fixing position and the proportionality was explained. However, it is also possible to start the scanning soldering from the lead (7) other than the temporary fixing position. . For example, scanning soldering can be performed from the other two sides where there is no temporary fixing.This means that if you start scanning soldering from the temporary fixing position, it may come off and float when soldering at the temporary fixing position. It is from.

In this way, temporary fixing is performed only for a small number of sills, and the rest is cholera.

〔Effect of the invention〕

As explained above, the method of the present invention has the effect of automatically performing high-precision soldering at high speed.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of an embodiment of the method of the present invention. DESCRIPTION OF SYMBOLS 1... 4-way flat package, 2... Printed circuit board, 3... Mounting head, 7... Lead, 10.1
1... Laser optical system, 8, 9... Temporary fixing laser beam,
14...Scanning laser light, 12...Conductive pattern. Agent: Patent Attorney Kensuke Norichika (and 1 other person) No. (A) (C)

Claims (3)

[Claims] (1) When transferring a plurality of electronic components with leads and automatically soldering the leads, after transferring the electronic components to the soldering position, at least one lead is heated in a spot to temporarily fix the electronic components. 1. A soldering method comprising: a step of sequentially spot-heating and scanningly soldering the soldered portions of the temporarily fastened electronic component leads. (2) The soldering method according to claim 1, wherein the leaded electronic component is an integrated circuit element having a large number of leads on two or four opposing sides. (3) The process of scanningly soldering after temporary fixing involves transporting the electronic component to the soldering position using a collet, fixing it with the collet, irradiating it with a laser beam, temporarily fixing it, and then releasing the collet. 2. The soldering method according to claim 1, wherein the soldering is carried out by scanningly irradiating a spot laser beam.