System and method for in-situ monitor and control of film thickness and trench depth
US7049156B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Mar 19, 2003 |
| Grant date | May 23, 2006 |
| Priority date | — |
| Expiry date | Jun 15, 2024 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L22/12
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention is directed to a system, method and software program product for calculating metrological data (e.g. layer thicknesses and depths of recesses and trenches) on a surface or structure, such as a semiconductor wafer. The present method does not require knowledge of the reflectivity or transmissivity of the surface or structure, but only a quantity related to the reflectivity or transmissivity linear transformation needs to be known. Initially, a simplified optical model for the process is constructed using as many parameters as necessary for calculating the surface reflectivity of the discrete regions on the wafer. Reflectivity data are collected from the surface of a wafer using, for instance, in-situ monitoring, and nominal reflectivity is determined from the ratio of the current spectrum to a reference spectrum. The reference spectrum is taken from a reference wafer consisting entirely of a material in which the reflection properties are well characterized. Both the observed and calculated data are transformed such that their vertical extents and spectrally averaged values coincide. By transforming both the observed data and calculated model such that their ve…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.