Method of isotropically dry etching a polysilicon containing runner with pulsed power
US5160408A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 27, 1990 |
| Grant date | Nov 3, 1992 |
| Priority date | — |
| Expiry date | Apr 27, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/32137
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
Disclosed is a method of isotropically dry etching a current conducting runner comprising polysilicon material which is formed on a silicon substrate wafer containing integrated semiconductor circuits. The method employs a parallel plate reactor which is controllable to provide intermittent pulses of power over the parallel plates. Gases are injected to within the reactor to provide a reactive gas mixture at a preselected pressure. Preselected intermittent pulses of power are applied to ionize the reactive gas mixture into a plasma state. Such intermittent pulses are defined by an RFon period, an RFoff period, and an RFrepeat period. The ratio of RFon:RFrepeat is preferably from about 0.35 to 0.60. The wafer is subjected to the intermittent pulses and reactive gas mixture at the preselected pressure for a preselected amount of time to selectively isotropically etch the current conducting runner. The invention has specific application to isotropically dry etching a WSi.sub.x /polysilicon sandwich structure. With such a structure, the preferred reactive gas mixture is SF.sub.6, Cl.sub.2, O.sub.2, and an inert carrier gas in approximate respective volume ratios of 10.0.+-.5%:2.0.+-.5%…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.