Reliability of Differently Shaped Solder Joints in Chip Resistor Under Drop Impact

This paper presents a comparative study that demonstrates the influence of solder joint shapes on the drop test performance of chip resistors. A 77 by 77 mm
²
test board that accommodates a total of 128 R1005 chip resistors (1.0 × 0.5 mm), which are mounted symmetrically is used. The chip resistors are assembled with four distinct shapes – concave, straight, tiny convex, and convex – using SAC305 (Sn3.0Ag0.5Cu) solder. Different shapes are achieved by controlling the size of the apertures in the stencil. The test condition follows the JEDEC standard condition B, with an impact of 1500g for a duration of 0.5 ms. The results indicate that the concave shape, which has the least volume of solder paste, exhibits the highest reliability, while the convex shape, with the largest solder volume, has the worst drop impact performance. Hence, it can see concluded that the solder shape has a significant impact of the drop test performance in chip resistors.