Low Temperature Oxide Passivation for Via-last/backside process

Plasma Enhanced Chemical Vapour Deposition (PECVD) is a widely used passivation process to obtain quality thin films at substrate temperature typically ranging from $150^{\circ} \mathrm{C}$ to $400^{\circ} \mathrm{C}$. PECVD passivation was developed with a low process temperature $\lt 120^{\circ} \mathrm{C}$ for temporary bonded wafers, for Via-last/backside process. Thermoplastic adhesives are used to bonded substrates to the carriers; for thinned wafers processing. Bonding adhesives are very sensitive to process temperature due to their thermoplastic behaviour, becoming more fluidic with increasing temperature. The reducing in adhesive viscosity can results in voids and delamination in the adhesive interface causing process failures. This paper discusses the application of a low temperature application of PECVD oxide liner for through silicon via (TSV) process. The low temperature TSV liner coverage and electrical performance were characterized.