JPH0228990A - Semiconductor device mounting method - 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 [Industrial Application Field] The present invention relates to a semiconductor device mounting method called a pin grid array in which lead pins are arranged in a matrix on the lower surface.

[Prior Art] In recent years, with the demand for smaller and thinner electronic devices and the increase in the number of I10 terminals due to higher functionality and diversification, semiconductor devices are becoming more and more multi-terminal. Diameter 28mm
In a semiconductor device having a size of 28 mm and a thickness of 3.6 mm, the number of terminals used is 160, the width of each terminal is 300 wn, and the interval between each terminal is about 650 mm.

Then, when mounting on a wiring board, each of these minute terminals must be connected to a minute wiring pattern provided on the wiring board, so the position of each terminal in the x, y, and z directions must be controlled with strict precision. required. For this reason, in semiconductor devices in which terminals are provided on all sides of the package, the increase in the number of terminals is approaching its limit.
The number of terminals of semiconductor devices will continue to increase in the future, and is expected to reach 400 to 600 or more in the near future.

In order to cope with the increase in the number of terminals in semiconductor devices, recently, as shown in FIG. (simply referred to as semiconductor devices) have been put into practical use.

Conventionally, in this semiconductor device, as shown in FIG. 4, through-holes 5 are provided in the wiring pattern 6 of the wiring board 4 in correspondence with the lead bins 2, and positioning stoppers 3 are provided in some of the lead bins 2. Each lead bin 2 was inserted into a through hole 5, and the lead bin 2 was soldered to a wiring pattern 6 using a solder dip or the like to be attached to a wiring board 4.

Furthermore, as shown in FIG. 5, surface mounting is also possible in which the lead bin 2 of the semiconductor device 1 is mounted on the wiring pattern 6 provided on the wiring board 4 without providing a through hole in the wiring board 4, and soldered by reflow or the like. It is being done.

[Problems to be Solved by the Invention] Recently, in order to mount semiconductor devices and electronic components on wiring boards at high density, a double-sided mounting method in which these are mounted on both sides of a wiring board has been promoted. In the method,
Each lead bin 2 can only be connected to the wiring pattern 6 on one side of the wiring board 4, and if you want to connect the lead bin 2 to the wiring pattern provided on the other side, connect the wiring pattern on both sides to the conductor. This not only complicates the structure but also increases costs.

Further, in the example shown in FIG. 4, the lead bin 2 protrudes to the other surface, which becomes an obstacle when forming a wiring pattern or attaching electronic components to this surface. Furthermore, in the example shown in FIG. 5, not only is positioning the lead bin 2 troublesome, but the lead bin 2
Since the semiconductor device 1 is simply soldered, it is unstable, and there is a risk that the semiconductor device 1 may fall off during transportation or due to vibrations, shocks, etc.

The present invention has been made in order to solve the above-mentioned problems, and an object of the present invention is to realize a mounting method for a semiconductor device that can be mounted on both sides of a wiring board, and that can be easily positioned and stably mounted on the wiring board. The purpose is to

[Means for Solving the Problems] A semiconductor device mounting method according to the present invention is such that at least two of the lead bins are configured to be longer than the other lead pins, and one surface of the wiring board corresponds to the lead bins. first
At the same time, a second wiring pattern is formed on the other side corresponding to the long lead bin, and a through hole is provided in this second wiring pattern.

[Function] By inserting a long lead bin into the through hole,
Positioning is performed in the front, rear, left, and right directions, and positioning in the vertical direction is performed by bringing other glue dowels into contact with the first wiring pattern. Then each lead bin is placed in the first.
Solder to the second wiring pattern.

Embodiment of the Invention FIG. 1 is a schematic diagram of an embodiment of the invention. Note that the same or equivalent parts as in the conventional example described above are given the same reference numerals, and the explanation thereof will be omitted. In the present invention, out of a large number of lead bins 2 provided on the lower surface of the semiconductor device 1, at least two lead bins 2, for example four at the four corners or two at the diagonal corners, are provided.
A is made longer than the other glue dobbin 2. That is, if the length of the other lead bin 2 is Ω, then the length Ω of this lead bin 2a is g1~g+t+α (however, t
is the thickness of the wiring board 4, α is the protrusion length from the wiring board 4)
shall be.

Also, on one side of the wiring board 4, wiring patterns 6 are formed corresponding to the short lead bins 2, and wiring patterns 6a are formed on the other side at positions corresponding to the long lead bins 2a. A through hole 5 is provided in 6a.

According to the present invention configured as described above, in order to mount the semiconductor device 1 on the wiring board 4, after applying (printing) solder cream or the like on the surface of each wiring pattern 6.6a, the long lead bin 2a is inserted into the through hole 5. Insert the semiconductor device 1 into
is mounted on the wiring board 4. At this time, the short lead bin 2 comes into contact with the wiring pattern 6 and is positioned in the vertical direction, and the long lead bin 2 inserted into the through hole 5
Front, rear, left and right positioning is performed by a. Then,
For example, if reflow is performed using a reflow machine, the short lead pins 2 will be attached to the wiring pattern 6 on one side of the wiring board 4, and the longer lead bins 2a will be attached to the wiring pattern 6 on the other side.
a, and the semiconductor device 1 is mounted at the correct position on the wiring board 4.

In this case, the long lead pins 2a are connected to a wiring pattern 6a on which the integrated circuit of the semiconductor device 1 is provided on the other surface of the wiring board 4.
The long lead pin 2a has a positioning function as well as a connection function, so when designing integrated circuits, packages, and wiring boards, it is necessary to consider the position of the long lead pin 2a so as to satisfy these functions.

FIG. 2 is a schematic diagram of another embodiment of the present invention. In this embodiment, the long lead pin 2b is formed thicker than the other short lead pins 2 to increase the rigidity, and the effect is as shown in FIG. 1. This is the same as in the embodiment.

In the above description, the case where two or four long lead pins are provided is shown, but the number may be two or more, and the number can be increased or decreased as appropriate depending on the design of the integrated circuit. If only one lead pin is needed to connect to the wiring pattern on the other side, one or more dummy bins dedicated to positioning may be separately provided.

[Effects of the Invention] As is clear from the above description, the present invention has a structure in which some of the lead pins of a semiconductor device are longer than other lead pins, and a wiring pattern is formed on one surface of the wiring board corresponding to the short lead pins. At the same time, a wiring pattern is formed on the other surface corresponding to the long lead pins, a through hole is provided in this wiring pattern, the long lead pin is inserted using the through hole as a guide, and the semiconductor device is mounted on the wiring board. As a result, the integrated circuit of the semiconductor device can be directly connected to the wiring patterns provided on both sides of the wiring board, making it possible to perform high-density mounting by double-sided mounting.

In addition, the semiconductor device is mounted on the wiring board using long lead pins and through holes as guides, which not only makes positioning easier, but also allows for stable mounting because it is soldered to both sides of the semiconductor board using long and short lead pins.
Implementation has a great effect, as there is no risk of it falling off.

[Brief explanation of the drawing]

Figures 1 and 2 are schematic diagrams of embodiments of the present invention, and Figure 3 (a
), (b) are bottom and side views schematically showing an example of a pin grid array type semiconductor device, and Figures 4 and 5 show mounting of a conventional pin grid array type semiconductor device on a wiring board. FIG. 2 is a cross-sectional view schematically showing an example. Semiconductor device, 2: lead pin, 2a, 2b: long lead pin, 4: wiring board, 5 varnished through hole, 6.6a:
wiring pattern. Figure 1 Figure 2

Claims (1)

[Claims] In a device in which a semiconductor device having a large number of lead pins arranged on a lower surface is mounted on a wiring board, at least two of the lead pins are configured to be longer than other lead pins, and a semiconductor device is mounted on one surface of the wiring board. A first wiring pattern is formed corresponding to the other lead pin, and a second wiring pattern is formed on the other surface corresponding to the long lead pin, and a through hole is provided in the second wiring pattern. A semiconductor device mounting method characterized by: