JPH09260431A - Connection structure of flip chip mounting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To relax the originating stress generated in the connection portion of a semiconductor chip with a board from the difference between the thermal expansion coefficients of the chip and board. SOLUTION: After Au ball bumps 3 of 25μm in ball portion height and 20μm in protrusion height are formed on electrode pads 6 of a semiconductor chip 2, Ag silicon pastes 4 are stuck on the top surfaces of the Au ball bumps 3 by a transcription method. Then, after the ball bumps 3 formed on the electrodes 6 of the semiconductor chip 2 are aligned with mounting pads 5 of a board 1 to mount the chip 2 on the board 1, the Ag silicon pastes 4 are heated and hardened to join the pads 5 to the bumps 3. Subsequently, after a liquid epoxy resin 7 is made to flow in the clearance between the semiconductor chip 2 and the board 1 by utilizing capillary phenomenon, the liquid epoxy resin 7 is heated and hardened to seal the clearance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flip-chip mounted connection structure.

[0002]

2. Description of the Related Art Conventionally, as shown in, for example, Japanese Patent Laid-Open No. 53-21771, in a structure in which a flip chip is mounted on a substrate, an epoxy resin, a silicon resin, a photo-curable resin is provided between the chip and the substrate. It is known that the thermal fatigue resistance due to the difference in thermal expansion between the chip and the substrate can be improved by filling with a resin material such as. In order to fill the narrow gap between the chip and the substrate with the resin, it is necessary to sufficiently reduce the viscosity of the resin, and as a result, other material characteristics such as thermal expansion coefficient and elastic modulus are restricted. In addition, the resin thickness between the chip and the substrate may vary due to the influence of the height variation of the bumps formed on the chip, and the resin thickness also varies around the chip. There was a problem that the resin was broken or peeled off from the substrate due to the difference in thermal expansion. As a technique for solving this problem, for example, there is a method shown in FIGS.

In the conventional flip chip connection method shown in FIGS. 2A to 2E, a solid and plate-shaped thermosetting resin 24 is provided between the flip chip 25 and the substrate 21 on which the flip chip 25 is mounted. And flip chip 2
5, the bump 26 of No. 5 and the solder 23 on the land (bad) of the substrate 21 face each other, and a heat treatment for a short time is performed at a temperature equal to or higher than the melting point of the solder.
Process of reflowing solder in a rigid state, and thermosetting resin 2
4, the heat treatment is carried out at a temperature not lower than the curable temperature and lower than the melting point of the solder to soften the thermosetting resin 24, and subsequently to cure the thermosetting resin 24. (For example, see Japanese Patent Laid-Open No. 2-96343) FIG. 3 is a sectional view showing a second conventional example. In the semiconductor chip mounting method shown in FIG. 3, bumps 36 are formed on the connection electrodes 35 of the semiconductor chip 33, a conductive resin layer 39 having elasticity in a cured state is provided on the bumps 36, and the bumps 36 are cured. The semiconductor chip 33 is bonded onto the substrate 31 by making the surface of the electrode 35 and the surface of the substrate 31 on the electrode pattern 32 side face each other and filling the adhesive resin 37 between the two opposing faces. (For example, JP-A-2-10394
No. 4)

The conventional flip-chip mounting connection structure described above has a drawback that cracks are generated when stress is applied to the connection portion due to the difference in thermal expansion coefficient between the substrate and the semiconductor chip.

[0004]

According to the flip-chip mounting connection structure of the present invention, the bumps formed on the electrode pads of the semiconductor chip and the mounting pads of the substrate are connected by a conductive resin having elasticity, and then the semiconductor chip is mounted. The liquid epoxy resin is poured into the gap left between the substrate and the substrate by utilizing the capillary phenomenon, and the liquid epoxy resin is heated and cured to seal the liquid epoxy resin.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 is a sectional view showing an embodiment of the present invention. The semiconductor chip 2 has an aluminum electrode pad 6,
The ball pump 3 is formed on the electrode pad 6. There is an Ag silicon resin 4 between the ball pump 3 and the mounting pad 5, and both are electrically connected.

The formation of this structure is performed as follows. The height of the ball portion is 25 μm on the electrode pad 6 of the semiconductor chip 2,
After forming the Au ball pump 3 having a protrusion height of 20 μm,
The Ag silicon paste 4 is attached to the upper surface of the Au ball pump 3 by a transfer method. Next, the mounting pad 5 and the ball pump 3 formed on the electrode pad 6 of the semiconductor chip 2 are aligned and mounted, and then the Ag silicon paste 4 is heat-cured and bonded. Next, the liquid epoxy resin 7 is poured into the gap between the semiconductor chip 2 and the substrate 1 by utilizing a capillary phenomenon, and then the liquid epoxy resin 7 is heat-cured and sealed.

[0008]

According to the flip-chip mounting connection structure of the present invention, since the ball bump and the mounting pad of the substrate are bonded with a resin having elasticity, it is based on the difference in the coefficient of thermal expansion between the semiconductor chip and the substrate. Since the stress generated in the connection portion can be relaxed, there is an effect that connection failure can be prevented.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

2A to 2E are cross-sectional views showing a first conventional example.

FIG. 3 is a sectional view showing a second conventional example.

[Explanation of symbols]

 1 substrate 2 semiconductor chip 3 ball bump 4 Ag silicon resin 5 mounting pad 6 electrode pad 7 epoxy resin

Claims (3)

[Claims] 1. A flip-chip mounting connection structure characterized in that a bump formed on an electrode pad of a semiconductor chip and a mounting pad on a substrate are connected by a conductive resin having elasticity. 2. A bump formed on an electrode pad of a semiconductor chip and a mounting pad on a substrate are connected by a conductive resin having elasticity, and then a liquid epoxy resin is filled in a gap left between the semiconductor chip and the substrate. A connection structure for flip-chip mounting, characterized in that the liquid epoxy resin is poured in by utilizing a capillary phenomenon, and the liquid epoxy resin is heat-cured and sealed. 3. The flip-chip mounted connection structure according to claim 2, wherein the conductive resin is Ag silicon paste.