Investigating the effect of chip component misalignment on its solder joint mechanical strength

In this paper an improved method is presented to determine the shear strength of misaligned chip components´ solder joints. To calculate the stress inside a solder joint in the case of shear loading, the applied force should be measured and the amount of joined surface (wetted area of the component metallization) should be calculated. Using the method we suggest, first we measured the exact position of the chip component after soldering. After, to determine the accurate value of the joined surface, a 3D profile calculation was carried out taking into consideration the exact position of chip components after soldering. The calculation of the profile was based on the principle of minimum energy. Then, the next stage was to determine the maximum force experimentally that the solder joint was able to withstand before failure in shear. Finite element modeling (FEM) was carried out to determine the stress in the solder joints at that maximum force. Our experiments and FEM investigations proved that the shear strength of misaligned components´ solder joints depends on the degree of component misalignment after reflow soldering.