| 摘要 |
PURPOSE:To match the thermal expansion coefficient of a semiconductor device with the thermal expansion coefficient of a substrate and avoid breakdown of CCB junctions by a method wherein a board made of, for instance, alumina which has a thermal expansion coefficient different from that of the device is applied to the surface of the semiconductor device opposite to the surface on which junction terminals are formed. CONSTITUTION:If the thickness of a semiconductor device 1, the thermal expansion coefficient of a thermal expansion control board 3 and the thickness of the board 3 are denoted by t1, alpha2 and t2 respectively, the total thermal expansion coefficient as the result of them can be expressed by an equation 1. Therefore, the thermal expansion control board 3 is so provided as to make this value alpha closer to the thermal expansion coefficient of a substrate. By laminating the thermal expansion control board 3 on the surface of the semiconductor device 1 opposite to the surface on which junction terminals 2 are formed, the total thermal expansion coefficient can be varied and the material and the thickness of the thermal expansion control board 3 are selected based upon the equation 1. With this constitution, when the semiconductor device 1 is jointed with the substrate 15, the difference in thermal expansion coefficient between the substrate 15 and the device 1 can be reduced so that the breakdown of the bump electrodes 2 can be avoided. |
