Integration of SAC and salicide processes by combining hard mask and poly definition
US6015730A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 5, 1998 |
| Grant date | Jan 18, 2000 |
| Priority date | — |
| Expiry date | Mar 5, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH10D1/692
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A process and structure are described wherein logic and memory share the same chip. Contacts to the memory circuits are made using the SAC process, thus ensuring maximum density, while contacts to the logic circuits are made using the SALICIDE process, thus ensuring high performance. The two processes have been integrated within a single chip by first depositing the various layers needed by the gate pedestals in both the logic and the memory areas and then forming the two sets of gate pedestals in separate steps. Gates located in the logic area are formed only from polysilicon while those located in the memory areas also have an overlay of tungsten silicide topped by a hard mask of silicon nitride. With the two sets of gates in place, source/drain regions are formed in the usual way. This includes growing of silicon nitride spacers on the vertical sides of the pedestals. The pedestals in the memory area are much longer than those in the logic area since they extend all the way to the top of the hard masks. The pedestals, on the memory side only, are given a protective coating of oxide (RPO). This allows the SALICIDE process to be selectively applied to only the logic side. Then, wh…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.