Method for reducing, by a factor or 2.sup.-N, the minimum masking pitch of a photolithographic process
US5328810A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 25, 1992 |
| Grant date | Jul 12, 1994 |
| Priority date | — |
| Expiry date | Nov 25, 2012 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S148/106
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The process starts with a primary mask, which may be characterized as a pattern of parallel, photoresist strips having substantially vertical edges, each having a minimum feature width F, and being separated from neighboring strips by a minimum space width which is also approximately equal to F. From this primary mask, a set of expendable mandrel strips is created either directly or indirectly. The set of mandrel strips may be characterized as a pattern of parallel strips, each having a feature width of F/2, and with neighboring strips being spaced from one another by a space width equal to 3/2F. A conformal stringer layer is then deposited. The stringer layer material is selected such that it may be etched with a high degree of selectivity with regard to both the mandrel strips and an underlying layer which will ultimately be patterned using a resultant, reduced-pitch mask. The stringer layer is then anisotropically etched to the point where the top of each mandrel strip is exposed. The mandrel strips are then removed with an appropriate etch. A pattern of stringer strips remains which can then be used as a half-pitch mask to pattern the underlying layer. This process may also be …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.