JPH0198237A - Method of mounting semiconductor device - Google Patents

Abstract

PURPOSE:To grow innumerable whiskers from the surface of a metallic film, and to join all electrodes completely by growing whiskers onto a substrate and thermocompression-bonding a bump formed onto a semiconductor element. CONSTITUTION:A land pattern 2 consisting of a copper foil is shaped onto the surface of a substrate 1 composed of glass epoxy, etc., and metallic films 3 composed of a metal, from which whiskers are easy to be generated, such as Sn are prepared to one parts on the land pattern 2 through a plating method. The metallic films 3 are left as they are for several hr in approximately 9.0% humidity at approximately 50 deg.C, and the whiskers 4 in several mum are grown from the surfaces of the metallic films 3. The whole surface is coated with a UV-cured resin coating 5. A semiconductor element 8 is aligned and superposed onto the resin coating 5 while a pattern surface is directed downward. Al electrodes 7 for connection to the outside are shaped onto the pattern surfaces in the semiconductor element 8, and metallic bumps 6 composed of Au, etc., for joining are formed onto the surfaces of the electrodes 7. The whiskers 4 are crushed by the bumps 6 through pressing by hold-down jigs 9 from the upper section of the semiconductor element 8, and the height of the whiskers 4 is equalized while all electrodes are connected through the whiskers.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for mounting semiconductor devices used in computers and the like.

Conventional technology In recent years, as electrical products have become lighter, thinner, and smaller, the I(J) mounted on them has changed from DIP types to flat packages, and even pair chips without packages are now being used. There is a type in which the chip electrode and the electrode on the substrate are brought into pressure contact, and the periphery thereof is coated with UV curing resin and fixed.

Problems to be Solved by the Invention However, with this method, as the number of electrodes increases and the IC chip size increases, the IC chip electrodes and substrate electrodes are no longer horizontal, creating a gap, and contact failure occurs when only pressure welding is used. There was a problem with this.

In order to solve this problem, the present invention reliably compensates for contact even if a gap occurs.

Means for Solving the Problem To achieve this objective, whiskers are grown on a substrate, the substrate is covered with a resin film, and the bumps formed on the semiconductor element are connected to the voice car by thermocompression bonding. .

In this method, even if there is a gap, the whiskers are crushed by the bumps formed on the semiconductor element, so the areas where the whiskers hit are crushed and become horizontal due to pressure contact, and contact is made between the whiskers and the whiskers.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a sectional view of a semiconductor device according to an embodiment of the present invention. In the figure, 1 is a substrate, and 2 is a substrate 1.
Land pattern formed on top, 3 is land pattern 2
The metal film provided above, 4 is a whisker, and 6 is a bump formed on the electrode 7 of the semiconductor element 8.

The manufacturing method will be described below with reference to FIGS. 2 to 6.

A land pattern 2 of copper foil is formed on the surface of a substrate 1 made of glass epoxy or the like to be mounted, and a metal film 3 of a metal that tends to generate whiskers, such as Sn, is formed on a part of the land pattern 2 using the foil method. (Figure 2).

Next, this is left for several hours at about 50'C and a humidity of about 9.0 qb, and whiskers 4 are grown by several micrometers from the surface of the metal film 3 (FIG. 3). Thereafter, the entire surface is covered with a UV-curable resin coat 6 (FIG. 4). Furthermore, the semiconductor element 8 is positioned and stacked on top of this with the pattern surface facing down. There is an Ad electrode 7 on the patterned surface of the semiconductor element 8 for external connection, and metal bumps 6 such as bumps for bonding are formed on this surface by a plating method or a transfer method. When pressure is applied from above the semiconductor element 8 with the holding jig 9 in this way, the voice car 4 is crushed by the bumps 6 and reaches a constant height, and all the electrodes are connected via the whiskers.

Next, in this state, UV light is irradiated to harden the resin.

Thereafter, a resin exterior coat 1o is applied to the entire IC chip 8 from the viewpoint of protection and reliability.

Effects of the Invention As described above, in the present invention, even if there is a gap between the electrodes, the whiskers grow in large numbers from the surface of the metal film and are pressed into contact with each other, so that all the electrodes can be completely joined. Therefore, it is more effective for large chips and I (3 chips) with many electrodes.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a semiconductor device according to an embodiment of the present invention, and FIGS. 2 to 5 are sectional views showing the same fabrication process. 1... Board, 2... Land pattern,
3... Metal film, 4... Whisker, 6
...Resin coat, 6...Bump, 7.
...Mult pole, 8...IC chip, 9.
...Press jig, 1o, old...resin exterior coat. Name of agent: Patent attorney Toshio Nakao and 1 other person 4-
1-Bo 54 Matata- 8-v Silk book series

Claims (1)

[Claims] A method for mounting a semiconductor device, which comprises growing whiskers on a substrate, covering the substrate with a resin film, and connecting bumps formed on a semiconductor element to the whiskers by thermocompression bonding.