Tateoki Miyauchi

Laser Diffusion Connection Technology for VLSI Programming

Summary A laser diffusion technology to connect poly-silicon conductors for programming VLSI memories is developed. It is based on the fact that a Nitrogen laser pumped dye laser of 510 nm wavelength irradiated on an intrinsic poly-silicon film in a VLSI, having 10 10 2 resistivity, decreases the film resistivity to 10 3 Ω. The mechanism of resistivity reduction is due to the laser heat diffusion of impurity into the intrinsic poly-silicon film. It is also clarified that the passivation film thick-ness on the intrinsic poly-silicon film changes laser reflectivity from zero to over 50%, affecting the condition of the process. The practical processing condition of laser diffusion connection for VLSI programming to enhance chip yield without damage is obtained.

Laser microformation of thin film on glass substrate for repair of transparent defects on high-density masks

Summary A new technique is developed for repairing transparent defects on high density masks for VLSI. A thin Ag-Ta organometallic film is first spin-coated onto a photomask and baked. Then an Ar laser microspot is applied to a small area on this film. After rinsing the mask with a solvent, an opaque layer remains at the laser-irradiated spot and the rest of the organometallic material is washed away. The opaque film formed locally by laser irradiation is dense enough to prevent light transmission and durable enough to withstand repeated washing with strong alkali and acid solutions.