Biased and serrated extension tube for ion implanter electron shower
US5903009A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 8, 1997 |
| Grant date | May 11, 1999 |
| Priority date | — |
| Expiry date | Sep 8, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J2237/0041
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A plasma-enhanced electron shower (62) for an ion implantation system (10) is provided, including an extension tube (66) having a replaceable graphite inner liner (88). The inner liner is biased to a low negative potential (-6 V) to prevent low energy secondary electrons generated by the electron shower target from being shunted away from the wafer, keeping them available for wafer charge neutralization. The electrically biased inner surface is provided with serrations (126) comprising alternating wafer-facing surfaces (128) and target-facing surfaces (130). During operation of the electron shower (62), photoresist or other material which may sputter back from the wafer collects on the wafer-facing surfaces (128), rendering them non-conductive, while the target-facing surfaces (130) remain clean and therefore conductive. The conductive target-facing surfaces provide a shunt (low resistance) path to electrical ground for high energy electrons generated in the electron shower.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.