JPS60123093A - Method of attaching semiconductor device - 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 (a) Technical Field of the Invention The present invention relates to a method for mounting a chip carrier with increased reliability.

(b) Technology background In order to realize higher speed and larger capacity computers, IC,
Semiconductor devices (hereinafter referred to as chips) such as LSIs have become larger and devices with 200 to 300 terminals are being put into practical use.
be.

Conventionally, a chip is fixed to a ceramic wiring board with a recess for chip mounting using various bonding methods, and then the wiring terminals (buds) of the chip and the wiring terminals provided around the four chip mounting parts of the wiring board are bonded. (Pads) are connected to each other by a method such as wire bonding to make a circuit connection, and in order to provide weather resistance and mechanical reliability, the semiconductor device is packaged and shipped as a semiconductor device.

The present invention relates to a method of mounting a multi-terminal semiconductor device on a printed wiring board with high reliability, which has been put into practical use recently.

(c) Conventional technology and problems A semiconductor device in which a chip is mounted on a ceramic substrate with printed wiring is called a chip carrier.
The terminal structure of this chip carrier includes one using a bottle and one using a bump.

In other words, those that use a bottle have a structure in which an IJ sock-like metal bottle protrudes from one side of the chip carrier, and this bottle is inserted into a through hole in a printed wiring board and soldered using a method such as flow soldering. Many conventional chip carriers are of this type. However, a large number of 200 to 300 terminals are
] This method is difficult due to space constraints for the purpose of forming them at a high density at intervals of about 7.

On the other hand, there is a face-down bonding method in which connecting bumps are formed in a matrix shape instead of pins and are directly connected to a printed wiring board.

Although this method is suitable for forming high-density terminals, the thermal expansion coefficient of the alumina substrate normally used as a chip carrier is significantly different from that of a printed wiring board made of synthetic resin such as epoxy or polyimide. Therefore, if a thermal cycle test is performed after connection, there is a problem that thermal stress will occur and the solder at the connection part will break.

(d) Purpose of the Invention The purpose of the present invention is to propose a mounting method capable of absorbing stress caused by differences in expansion coefficients when connecting a chip carrier having a high density and a large number of connection terminals to a printed wiring board. do.

(e) Structure of the Invention The purpose of the present invention is to mount a semiconductor chip with a large number of terminals on the four central parts of the back surface of the board, and connect it to the conductor pattern of the printed wiring board through a plurality of pandas provided around the back surface of the board. A buffer plate is provided between the chip carrier to be connected and the printed wiring board, in which metal wires are embedded and protruded from the upper and lower surfaces in accordance with the bump arrangement positions of the chip carrier, and the protruding conductive wires of the buffer plate are interposed between the chip carrier and the printed wiring board. This can be achieved by making a circuit connection with a printed wiring board.

(f) Embodiments of the Invention The present invention utilizes the elasticity of thin lead wires to absorb stress caused by differences in expansion coefficients.

FIG. 1 shows a plan view (5) and a side view of a buffer plate according to the invention in the simplest case.

In other words, a synthetic resin plate 1 with the same dimensions as the chip carrier is made of a comparative material such as steel (Cu) and has a diameter of 0.1~
A bottle 2 of 0.2 [ii] is vertically embedded and molded so that a part of it protrudes from the synthetic resin plate 1. Tebi/2
By applying solder coating to the buffer plate 3 according to the present invention, the buffer plate 3 according to the present invention is completed.

FIG. 2 shows the procedure for mounting the chip carrier 4 on the printed wiring board 5 using the buffer plate 3.

The chip carrier 4 shown in this embodiment is an IC.

A chip 7 such as an LSI is bonded to a recess provided on the back surface of the board, and connected by wire bonding to a pad part of a printed wiring board that is circuit-connected to the panpro.

Conventionally, the bumps 6 of the chip carrier 4 and the connection pads 8 of the printed wiring board 5 were properly aligned and bonded by direct soldering, but in the processing method according to the present invention, A buffer plate 3 is placed on top of the printed wiring board 5, and a chip carrier 4 on which a semiconductor chip 7 is mounted is placed on the printed wiring board 5 through a through hole, a bottle 2, and a conductor 2.
After positioning is performed so that the and bumps 6 are correctly opposed to each other, heating is performed by applying hot air from the side to melt the contact portions and integrate them.

When such a mounting method is adopted, since the conductive wire 2 protruding from the buffer plate 3 absorbs strain, no damage due to thermal fatigue occurs even after repeated thermal cycles, and highly reliable mounting can be achieved.

Example: Bottles made of pure copper wire with a diameter of 0.2.hi:l were embedded in an epoxy resin plate with an area of 20 mm square and a thickness of 1 mm at a pitch of 0.5 mm, and placed vertically. 0.2(
gm) were molded so that they protruded, and this was immersed in a solder bath to cover the protruding parts of the bottle with solder to create a buffer plate.Next, this buffer plate was interposed between the chip carrier and the printed wiring board. Although the solder was fused using hot air, the chip carrier mounted in this way is stable and does not suffer from disconnection even when subjected to thermal cycles.

(Mean Effect of the Invention) The present invention has improved the mounting method due to the increase in speed and capacity of semiconductor devices, and chip carriers with a large number of bumps have come to be used. Therefore, poor connection with the printed wiring board is more likely to occur.

The present invention was made with the aim of eliminating the occurrence of defects in the cage, and by implementing the present invention, it becomes possible to prevent the occurrence of defects.

[Brief explanation of the drawing]

FIG. 1 shows a plan view (A) and a side view (A) of a buffer plate according to the present invention.
B), and Figure 2 is a side view explaining how to use the buffer board, where the figure shows the chip carrier, (B) shows the buffer board, and (0 shows the printed wiring board. In the figure, 1 shows the synthetic resin board, 2 shows the buffer board. is a pin, 3 is a buffer plate, 4 is a chip carrier, 5 is a printed circuit board, 6 is a bump, 7 is a chip,
8 is a connection pad.

Claims (1)

[Claims] A chip carrier and a front-packed printed wiring board on which a semiconductor chip with a number of terminals is mounted in a central recess on the back side of the board and connected to a conductive pattern of a printed wiring board through a plurality of bumps provided around the back side of the board. A buffer plate with embedded metal wires protruding from the upper and lower surfaces in accordance with the placement position of the chip carrier's bang is provided between the chip carrier and the circuit connection between the chip carrier and the printed wiring board by interposing the practical conducting wire of the buffer plate. A method for mounting a semiconductor device, characterized in that: