Method for forming local interconnects using selective anisotropy
US4957590A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 5, 1989 |
| Grant date | Sep 18, 1990 |
| Priority date | — |
| Expiry date | Sep 5, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L2924/0002
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method for etching titanium nitride local interconnects is disclosed. A layer of titaniun nitride is either formed as a by-product of the formation of titanium silicide by direct reaction or by deposition. The location of the interconnects is defined by patterning photoresist at the desired locations. A plasma etch using a chlorine-bearing agent such as CCl.sub.4 as the etchant etches the titanium nitride anisotropically at those locations covered by photoresist, and isotropically elsewhere, so that filaments of the titanium nitride are removed without undercutting the photoresist mask. The etch is selective relative to the underlying material, such as a refractory metal silicide, refractory metals, or silicon, due to the passivation of the underlying material by the carbon atoms of the CCl.sub.4. The selectivity, together with the selective anisotropy, even allows significant overetch of the material to remove the filaments without undercutting the masked interconnect material.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.