Etching of semiconductor structures that include titanium-based layers
US9330937B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Nov 13, 2013 |
| Grant date | May 3, 2016 |
| Priority date | — |
| Expiry date | Dec 22, 2033 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D64/691
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
Abstract
Two-step process sequences uniformly etch both tungsten-based and titanium-based structures on a substrate. A sequence of wet etches using peroxide and heated nitric acid uniformly recesses a metal stack that includes W, TiN, and TiAl. W, TiN and TiC are uniformly recessed by a peroxide etch at ˜25 C followed by an acid solution with a very small amount of added peroxide at ˜60 C. TiC is etched without etching trench oxides or other metals in a work-function metal stack by either (1) highly-dilute of ultra-dilute HF at 25-35 C, (2) dilute HCl at 25-60 C, (3) dilute NH4OH at 25-60 C, or (4) solution (2) or (3) with small amounts of peroxide. Other metals in the stack may then be plasma-etched without being blocked by TiC residues.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.