We recently encountered a soldering issue with a DDR memory BGA (Ball Grid Array). The problem identified was HIP (Head-In-Pillow) — two balls with non-wetting under the BGA package were affected. To investigate, we sent someone to the field to assess the customer’s operation, discovering that the product failed to power on. Interestingly, applying finger pressure to the DDR memory component would successfully power it on.
Why did this occur? The production line claimed the products underwent a 12-hour power-on Burn/In (B/I) process at 40°C but didn’t screen out the defect. So, why did we still observe this type of BGA soldering defect in the field?