Methodology for improved semiconductor process monitoring using optical emission spectroscopy
US6046796A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 22, 1998 |
| Grant date | Apr 4, 2000 |
| Priority date | — |
| Expiry date | Apr 22, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J37/32972
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In a semiconductor process which utilizes a plasma within a process tool chamber, a method of using optical emission spectroscopy (OES) to monitor a particular parameter of the process is disclosed. A first wavelength present in the plasma is determined which varies highly in intensity depending on the particular parameter by observing a statistically significant sample representing variations of the particular parameter. A second wavelength of chemical significance to the process is also determined which is relatively stable in intensity over time irrespective of variations of the particular parameter, also by observing a statistically significant sample representing variations of the particular parameter. These two wavelengths may be determined from test wafers and off-line physical measurements. Then, the intensity of the first and second wavelengths present in the plasma is measured on-line during normal processing within the process tool chamber, and the ratio between the first and second wavelength's respective intensities generates a numeric value which is correlated to the particular parameter. As an example, such a method may be used to generate a reliable alarm signal ind…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.