In-line detection and assessment of net charge in PECVD silicon dioxide (oxide) layers
US5963783A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 8, 1998 |
| Grant date | Oct 5, 1999 |
| Priority date | — |
| Expiry date | Jun 8, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/14
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The present method provides for the detection and assessment of the net charge in a PECVD oxide layer deposited on a surface of a semiconductor substrate. Electrical potential differences across PECVD oxide layers on as-produced semiconductor substrates are measured. Resultant PECVD oxide charge derivative values are plotted on an control chart and compared to calculated control parameters. All measurement techniques are non-contact and non-destructive, allowing them to be performed on as-processed semiconductor substrates at any time during or following a wafer fabrication process. In a first embodiment, a contact potential difference V.sub.CPD between a vibrating electrode and the semiconductor substrate is measured while the semiconductor substrate beneath the vibrating electrode is subjected to a constant beam of high intensity illumination. The resultant value of V.sub.CPD is equal to the electrical potential difference across the PECVD oxide layer V.sub.OX (plus a constant). In a second embodiment, the semiconductor substrate is not illuminated curing the measurement of V.sub.CPD. A conventional SPV apparatus is used to measure the surface barrier potential V.sub.SP of the se…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.