28nm Planar Flow

The NiPt Salicide Metal Strip is positioned immediately after the first rapid thermal anneal (RTP1) to establish electrical isolation between the gate, source, and drain regions [P1][T1][T2]. During the upstream RTP1, a solid-state reaction is driven selectively at the interfaces where the deposited NiPt alloy directly contacts the exposed silicon substrate [T2][P4]. The metal deposited over dielectric spacers and isolation oxides remains unreacted due to the lack of a silicon source to initiate…

• [High] Spacer Bridging and Gate-to-S/D Electrical Shorts: Insufficient dissolution and removal of the unreacted NiPt alloy, particularly the noble Pt-rich residues on the vertical sidewalls of the dielectric spacers, leaves conductive metallic remnants [P1][P3]. During the subsequent high-temperature RTP2, these residual metal atoms undergo further solid-state diffusion and react with adjacent silicon regions, creating a continuous, low-resistance metallic bridge that electrically shorts t…