JPS6057995A - Method of bonding electronic part - 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 [Field of Application of the Invention] The present invention relates to a method of bonding electronic components and substrates.

[Background of the invention]

The conventional method for joining parts is to apply solder paste to the bonding pad of the second board, bring the leads of one part into contact with the solder paste, and then reflow the solder by heating to perform the joining. This method includes the steps of applying semi-Ill V to the bonding pad, and installing the bonding pad and component leads together (see Figure 111).
(Fig. 112) and the leads and bonding pads by heating? The joining process () consists of 133 figures.

, 171 and 112 show the state in which the component 54 held by the chuck 4 is installed in accordance with the solder paste (3) applied to the bonding pad 2 of the board (1).

However, the bonding surface of the lead 6 of an electronic component usually has a ±0.2
There is a variation of about 10B. Particularly in the case of LSIs with dozens of leads, after manufacturing they are soldered onto baby boards, passed through an inspection process, and then supplied to the board assembly process. In II, after the LS1 component is removed from the baby board, it is installed on the board as shown in Figures 1 and 2. When removing, variations due to the adhesion of melted solder are added, and variations of about I: 0, 511 occur.

For this reason, simply placing the component 5 on the pad 2 of the board will result in
As shown in Fig. 4, gaps such as J, J, etc. are created,
Connection by half-11 reflow becomes impossible.

Therefore, it is easy to think of pressing the component 57 against the board, but the problems with this method are (1) It is unclear how much pressure (displacement or force) is required for all the leads to come into contact with the bonding pad. (2) If even one lead is extremely retracted or protrudes, there is a risk of damage to the leads if the component 4 is pressed against the board until all the leads, including that one, touch the bonding pad. There is.

[Purpose of the invention]

The purpose of the present invention is to eliminate lead floating caused by unevenness in the lead itself of the component or uneven thickness of solder attached to the lead when removed from the baby board, and to provide a bonding pad between the lead and the board. The aim is to ensure the connection between the parts.

[Summary of the invention]

A feature of the present invention is that variations in the joint surfaces of individual leads of a component are measured in advance, and only a correction value is calculated based on the difference between the maximum and minimum measured values.

By pressing the component against the board, all leads are surely brought into contact with the board, and in this state half [11 reflow is performed to bond the component and the board.

[Embodiments of the invention]

Embodiments according to the present invention will be explained with reference to FIGS. 1 and 5 to J and 12.

Figure 5 shows a method for measuring the position of the lead bonding surface.

The component 5 is suctioned onto the upper surface of the main body by a component suction head 7. There are TV left cameras on both sides of the component 5, and images obtained by these cameras are processed by an image processing device 9 to determine the position of each lead bonding surface.

An example of an image obtained by a TV camera is shown in Figure A'6. The x-axis and y-axis are set as shown, and the central axis of the component suction head 7 is aligned with x-0 1, 6.

Align the component suction surfaces to y...OK. Further, the component is suctioned so that the center of the component 5 coincides with the central axis of the suction head, that is, X=0. On top of that, the lead position of the i-L side of the part (obvious from the design value), xL,' (x (xL
By searching for , it is possible to easily obtain the bonding surface position yL even if the bonding surface of the lead 6 is bulged with solder 10 as shown in FIG.

The bonding surface position If of n leads obtained by this method
Maximum value ax + minimum value y among yl,..., 7n
'min, the correction value P - (ymax - yTnin
) is processed by the image processing device shown in FIG. 5 and sent to the bonding control device 11. Here, 4 is a margin that takes into account variations in the thickness of the solder paste on the bonding pad, and is 2m.
It is usually a fairly small value compared to ax Pm1n.

The joining method will be explained with reference to Figures 128 to 1r10.

First, the component 5 is placed on a predetermined bonding pad 2 on the substrate 1.
1 tor (Figure 1r8). Next, as shown in Figure 9, the head body 12 is lowered until the lower end of the suction head body 12 touches the suction plate 13.

As a result, the compression spring 14 built into the head allows
The component is lightly pressed onto the board. In this state, there is a gap J, J, between the glue board 6 and the board pad 2.
, etc. exist. In order to eliminate this gap, the suction plate 13 is forcibly lowered by the correction value p using the head body 12, thereby eliminating all gaps. In this state, half [
If the roll r1- is performed, all the leads can be reliably bonded to the substrate.

An embodiment of a component suction head is shown in Figure 11.

A shaft 15 of the suction plate 13 is engaged with the head body 12 so as to be vertically slidable. The head body 12 is provided with a detection switch 16 for detecting contact between the head body 12 and the suction plate 13.

The head body 12 is moved by a belt 18 by a servo motor 17.
．． 19. Pulley 20.21.22.23. Paul Nut 24. and a ball screw 25 attached to the head body.
It is driven up and down through the This vertical movement amount can be arbitrarily set by the welding apparatus control section 11 controlling the servo motor with the encoder 26.

With the configuration of this component suction head, (rehead main body 12
(2) After the detection switch 16 is tapped, the head body is lowered until it contacts the suction plate 13.
:P only head body 12? It becomes possible to lower it further.

An example of the overall configuration of the device including lead detection and bonding is shown in Fang 12.
As shown in the figure. The device supplies a camera 81 for detecting the lead of the component suction unit 31, which is slidably attached to the guide rail 3o.) 32. Board 1
(-X-Y table 3 that can be positioned horizontally)
3. Laser oscillator 34 for performing solder reflow. Laser irradiation section 35° laser lead fiber 36. It consists of a laser emitting unit drive arm 37.

A component suction unit 31 located at a suction position A suctions the electronic components sent through the chute.

The configuration of the component suction unit 31 is 1.3t' 2 in Figure 11.
It is shown surrounded by a dotted chain line. The leads of the suctioned parts are detected by 22 111v cameras 8, and the image processing device 9
Calculate the correction amount. The component suction unit 31 moves to the joint skin 1) in a state in which the component is suctioned. At this time, 1
If there is a part in the book with an extremely poor lead position, it is discarded on the reject table 38. Hold substrate 11. According to the instruction 1/I" from the uppermost welding device control unit 11 of the X/-Y table 33, the location to be welded is directly below the
Move as you come. The component suction unit 51 performs the operations shown in Figures 8 to 10, and picks up the component 4PjVC until all the leads are in close contact with the bonding butts.

Press.

In this state, solder reflow 1-1 parts are joined.

In this embodiment, a solder paste flow means and a 1° laser are used.

L/ -f Unit C, laser emission &? 534 (Y
A (i-laser or CO, laser) and a laser irradiation unit drive system 39. The laser irradiation section 35 is located at the point where the leads are purchased, and irradiates the laser pulses from the laser oscillator 54 or ") onto one lead on each side of the component (total of two leads) to reflow the solder. Laser irradiation section 357, 7.

The drive system 39 is moved l: and the laser is irradiated onto the leads repeatedly to complete the connection of all the leads of the component. Thereafter, the component suction unit releases the force pressing the component.

Although this embodiment shows an IJA case in which the present invention is applied to an automation device, the embodiment is not limited to this.

For example, lead recognition may be performed using a mechanical probe, microscope, etc., and component suction may be performed using a mechanical chuck. Alternatively, the components may be aligned on the board manually. Furthermore, in the case of a component having leads on four sides, it is also possible to provide four TV cameras.

〔Effect of the invention〕

According to the present invention, it is possible to eliminate variations in the lead joint surfaces of electronic components, and furthermore, to reduce variations in the lead bonding surface of electronic components, and also to improve
Joining? Even if there is variation in the thickness of the solder remaining on the bonding surface of the lead due to removal, all leads can be reliably contacted with the bonding band on the board based on the variation data.8.

Since the process can be carried out with a high degree of reliability, bonding of electronic components using the half-mII flow can be performed with high reliability.

[Brief explanation of drawings]

Figures 1 to 3 are sketch diagrams showing the conventional bonding process of electronic components, Figure 4 is a front view showing the gap between the lead and the pad,
Is figure 5 the lead position measurement method? Side views 1 and 1-6 are front views of the parts. Figure 7 is a detailed view of the lead part.
Figures 8 to 10 are diagrams showing the method of joining parts according to the embodiment of the present invention, Figure 11 is a front view of the parts suction unit, and Figures 1 and 12 are sketches of the embodiment of the present invention. 2)
. 1... Board, 2... Ponding pad, 6...
Solder paste, 4... Chuck, 5... Electronic cuff ((
Product, 6... Lead, 7... Component suction head 58...
-TV nonomera, 9...image processing device, 11...bonding device 6 control section, 12...suction head main body, 30...
・Guide rail, 31...Component suction unit, 32・
・・Shoot, daytime...

Claims (1)

[Claims] In the method of bonding electronic components to a board, the positions of the bottom surfaces of multiple leads of the electronic component are measured, the difference between the maximum and minimum values of this position data is used as a correction value, and the electronic component is placed in a predetermined position on the board. After placing it in position, press it against the electronic component ball/board by the above correction value, and then press the F and L of all leads.
- A method for joining an electronic component, which comprises joining an electronic component and a board by reflowing the solder 1 while bringing the solder paste surfaces into close contact with each other.