Cleaning, etching and oxidation are the most frequently used processes in the semiconductor industry. Optimization of these processes and contamination control affect both manufacturing yield and performance of devices. Typically the contamination effect of these processes is monitored either by measuring bulk carrier lifetime or surface charge.

Bulk carrier lifetime (or carrier diffusion length) is one of the most sensitive methods of monitoring effect of contamination. It requires driving contaminants deposited on the surface into the bulk, and therefore requires a high temperature process following cleaning/etching procedure.
 
Surface charge can be measured directly after cleaning and etching processes, but the sensitivity of the standard measurement methods is limited to charges not exceeding surface inversion charge. Since common cleaning procedures, such as SC-1 for n-type Si or HF for p-type Si, typically produce a surface charge exceeding the inversion limit (which is further distorted by the molecular charge left by cleaning procedure), previous attempts of in-line contamination monitoring were unsuccessful. DSPC© uniquely solves this problem by measuring not only the surface charge, but also the surface carrier capture velocity and surface state density.

DSPC© offers monitoring bulk contamination effect of cleaning, etching and oxidation processes by measuring bulk carrier lifetime without additional surface conditioning. Surface contamination and damage is monitored by measuring the surface charge and the surface carrier capture velocity and/or surface state density. Measurement of these parameters offers unique solution to the in-line contamination monitoring not available with other techniques.