Mesa isolation Refill Process for Silicon on Insulator Technology Using Flowage Oxides as the Refill Material
US5882981A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 29, 1997 |
| Grant date | Mar 16, 1999 |
| Priority date | — |
| Expiry date | Jul 29, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S148/044
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
After formation of a sandwich over a substrate of a layer of silicon dioxide (3) followed by a layer of silicon (1) having a pad oxide (7) thereon and a patterned silicon nitride layer (9) over the pad oxide, the unmasked portion of the pad oxide and silicon are removed to provide mesas of silicon with silicon nitride thereover and possibly removal of some of the buried oxide layer. A flowable insulator (15), preferably silsesquioxane (H.sub.x SiO.sub.1.5, where x.ltoreq.1, depending upon the level of polymerization) in a contaminant-free, high purity solvent which is later removed during an annealing step, is placed over the exposed surface such that it fills the voids between the mesas of silicon with silicon nitride thereon and extends over the nitride. The flowable insulator, due to its flowability, provides a generally planar surface. The flowable insulator is etched back and a cap oxide (17) is optionally deposited over the etched back insulator layer. The cap oxide layer (if used), some insulator and nitride are then etched away, leaving the pad oxide over the silicon. The processing is then completed by removing the pad oxide, growing a gate oxide and then forming the gate …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.