Plasma etch is a key process in modern semiconductor manufacturing facilities as it offers process simplification and yet greater dimensional tolerances compared to wet chemical etch technology. The main challenge of operating plasma etchers is to maintain a consistent etch rate spatially and temporally for a given wafer and for successive wafers processed in the same etch tool. Etch rate measurements require expensive metrology steps and therefore in general only limited sampling is performed. Furthermore, the results of measurements are not accessible in real-time, limiting the options for run-to-run control. This paper investigates a Virtual Metrology (VM) enabled Dynamic Sampling (DS) methodology as an alternative paradigm for balancing the need to reduce costly metrology with the need to measure more frequently and in a timely fashion to enable wafer-to-wafer control. Using a Gaussian Process Regression (GPR) VM model for etch rate estimation of a plasma etch process, the proposed dynamic sampling methodology is demonstrated and evaluated for a number of different predictive dynamic sampling rules.
|Title of host publication||2013 24th International Conference on Information, Communication and Automation Technologies, ICAT 2013|
|Publication status||Published - 16 Dec 2013|
|Event||2013 XXIV International Conference on Information, Communication and Automation Technologies (ICAT) - Sarajevo, Bosnia and Herzegovina|
Duration: 30 Oct 2013 → 1 Nov 2013
|Conference||2013 XXIV International Conference on Information, Communication and Automation Technologies (ICAT)|
|Country/Territory||Bosnia and Herzegovina|
|Period||30/10/13 → 1/11/13|