TIN AS A DIFFUSION BARRIER IN THE TI-PT-AU BEAM-LEAD METAL SYSTEM

The Ti-Pt-Au beam-lead metallization system has demonstrated good reliability for connections on integrated circuits. In certain otherwise desirable process sequences, however, interdiffusion of these metal films (e.g. titanium and platinum) can result in the formation of unetchable intermetallic compounds that may impair device performance. The incorporation of a thin (approximately 150 Å) titanium nitride (TiN) layer between the titanium and platinum films inhibits the formation of Ti-Pt intermetallic compounds and allows these process sequences to be used to full advantage. The properties of TiN are discussed. Electron microprobe and secondary ion mass spectrometry analyses were used to measure the effectiveness of TiN as a diffusion barrier. © 1979.