Migration issues in sintered-silver die attaches operating at high temperature

• Assessment of the silver migration issue for high temperature die attaches.
• A mitigation solution is proposed (fluorinated parylenes).
• Lifetime with parylene exceeds 1000 h at 275 °C.

Silver sintering is a promising alternative to high melting point (HMP) solders which contain lead. Indeed, it offers better thermal and electrical properties and can operate at higher temperature. However, silver tends to migrate in presence of electric field, oxygen (or moisture) and high temperature, causing short circuits. In this paper, we assess the extent of this issue, and we evaluate the protective effect of a thin layer of parylene. It is shown that silver migration occurs rapidly (tens to hundreds of hours at 300 °C), but that parylene offers a good mitigation of this issue.