Combined Fatigue Test for C4 Solder Joints
Original Publication Date: 1985-Oct-01
Included in the Prior Art Database: 2005-Feb-19
A critical consideration in the structural performance of controlled collapse chip connection (C4) solder joints is their resistance to thermal cyclic loading projected over the life of a module. The loading is due to thermal mismatch between the chip and substrate bridged by the C4 joint. This load results in shear stress on the C4s, and is proportional to the distance of the particular C4 to the "neutral point" located in the middle of the chip. This test for C4 solder joints combines mechanical loading in shear and normal loading to establish the cyclic fatigue strength of the C4 joints. A rigid block 11 is attached to the chip 12, and the substrate 13 is mounted along an incline defined by the angle b. The displacement load is achieved by vertical stroking.