Heat conductive bonding material, semiconductor package, heat spreader, semiconductor chip and bonding method of bonding semiconductor chip to heat spreader

Abstract

A heat conductive bonding material 6 has a first bonding region 7 transferring heat of a semiconductor chip 1 to a heat spreader 4, and a second bonding region 8 relaxing a thermal stress generated between the semiconductor chip 1 and the heat spreader 4.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing in enlargement a bonding area between a semiconductor chip and a heat spreader of a semiconductor package according to a first embodiment;

FIG. 2 is a sectional view showing in enlargement the bonding area between the semiconductor chip and the heat spreader of the semiconductor package according to a second embodiment;

FIG. 3 is a sectional view showing in enlargement the bonding area between the semiconductor chip and the heat spreader of the semiconductor package according to a third embodiment;

FIG. 4 is a sectional view showing in enlargement the bonding area between the semiconductor chip and the heat spreader of the semiconductor package according to a fourth embodiment;

FIG. 5 is a view illustrating a semiconductor package in section according to the prior art;

FIG. 6 is a sectional view showing a state where the semiconductor package according to the prior art is heated;

FIG. 7 is a sectional view showing in enlargement the bonding area between the semiconductor chip and the heat spreader of the semiconductor package according to the prior art;

FIG. 8 is a view showing an analysis model used for analyzing in simulation a thermal stress occurred in the semiconductor package;

FIG. 9 is a table showing conditions in a simulation analysis model manufacturing step;

FIG. 10 is a table showing conditions of the respective simulation analysis models;

FIG. 11 is an equipressure contour representing a stress distribution of a tensile stress in a Z-axis direction, which occurs in a heat conductive bonding material;

FIG. 12 is a graph showing a stress distribution map that is plotted along an axis of Y═X;

FIG. 13 is a graph showing the stress distribution map that is plotted along an axis of Y=0;

FIG. 14 is a graph showing the maximum stress occurred in each analysis model; and

FIG. 15 is a table showing a result of a reliability test of an actual semiconductor package according to the first embodiment.

Claims

1. A heat conductive bonding material comprising: a first bonding region transferring heat of a semiconductor chip to a heat spreader; anda second bonding region relaxing a thermal stress generated between the semiconductor chip and the heat spreader.

2. A heat conductive bonding material according to claim 1, wherein the second bonding region is formed adjacently to a side surface of the first bonding region so as to cover the entire side surface of the first bonding region.

3. A heat conductive bonding material according to claim 1, wherein the second bonding region is formed so that its thickness in a direction perpendicular to a bonding surface between the semiconductor chip and the heat spreader is larger than that of the first bonding region.

4. A semiconductor package comprising: a semiconductor chip;a heat spreader; anda heat conductive bonding material including a first bonding region transferring heat of the semiconductor chip to the heat spreader, and a second bonding region relaxing a thermal stress generated between the semiconductor chip and the heat spreader, wherein the semiconductor chip is bonded to the heat spreader by use of the heat conductive bonding material.

5. A semiconductor package according to claim 4, further comprising a thin type circuit board that is flip-chip-packaged onto the semiconductor chip.

6. A heat spreader comprising a first bonding surface that is bonded to a first bonding region transferring heat of a semiconductor chip to the heat spreader; and a second bonding surface that is bonded to a second bonding region relaxing a thermal stress generated between the semiconductor chip and the heat spreader.

7. A heat spreader according to claim 6, wherein the second bonding surface is formed so as to embrace an outer edge of the first bonding surface.

8. A semiconductor chip comprising: a third bonding surface that is bonded to a first bonding region transferring heat of the semiconductor chip to a heat spreader; anda fourth bonding surface that is bonded to a second bonding region relaxing a thermal stress generated between the semiconductor chip and the heat spreader.

9. A semiconductor chip according to claim 8, wherein the fourth bonding surface is formed so as to embrace an outer edge of the third bonding surface.

10. A bonding method comprising: bonding a semiconductor chip to a heat spreader by use of a heat conductive bonding material including a first bonding region transferring heat of the semiconductor chip to the heat spreader, and a second bonding region relaxing a thermal stress generated between the semiconductor chip and the heat spreader.