Improvement of the adhesion of new memory packages by surface engineering

For the assembly of new memory modules for the PC market, investigations were carried out concerning lead free solder contacts for the BGAs and new green plastics, which cause an improvement of the adhesion during the packaging process. Since there were frequent delaminations in the packaging process with these new memory chip materials during the mold processes, solder ball attach or the SMT reflow soldering, a special plasma pre-treatment was introduced. With this plasma pre-treatment, a significant improvement of the surface energies of the involved silicon chip, BT interposer material and solder mask was obtained and thus a better adhesion of the mold compound was achieved. For proof, measurement of the contact angle and computation of the surface energy on the surfaces treated in the plasma showed this improvement, in comparison to untreated samples.