Method of fabricating a Si3N4/polycide structure using a dielectric sacrificial layer as a mask
US6342452B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 2000 |
| Grant date | Jan 29, 2002 |
| Priority date | — |
| Expiry date | May 18, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/32137
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
According to the disclosed method, there is provided a structure consisting of a silicon substrate coated with a bottom thin SiO2 layer, a doped polysilicon layer, a refractory metal layer and a top Si3N4 capping layer. Said refractory metal and doped polysilicon layers will form a polycide layer under subsequent thermal treatments. First, a sacrificial layer of a dielectric material such as oxynitride is deposited onto the structure. Oxynitride is impervious to UV radiation and has excellent conformal properties. Then, a layer of a photoresist material is deposited onto the structure and patterned to form a mask. Now the dielectric and top Si3N4 layers are anisotropically etched using the photoresist mask. The mask is stripped and the refractory metal and doped polysilicon layers are anisotropically dry etched down to the SiO2 layer using the patterned dielectric layer as an in-situ hard mask. A conformal layer of Si3N4 is deposited onto the structure, then anisotropically dry etched until the thin SiO2 layer is exposed to form the Si3N4 spacers. Diffusion regions are formed in the substrate by ion implantation. A layer of BPSG is deposited onto the structure and planarized. Conta…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.