Patent ID: 7105398

Claim:
A method for determining encroachment of an insulator structure in a semiconductor device, the structure having thick and thin regions, including a transition region formed therebetween, said method comprising: a) obtaining a line width roughness (LWR) measurement at at least one location along each thick, thin and transition regions; b) determining a threshold LWR measurement value based on said LWR measurements; c) defining a region of interest (ROI) and obtaining a further LWR measurement in said ROI; d) comparing said LWR measurement in said ROI against said threshold LWR measurement value; and, e) providing a notification that either encroachment of said structure is present when said LWR measurement in said ROI is below said threshold LWR measurement value, or that no encroachment of said structure is present when said LWR measurement in said ROI is above said threshold LWR measurement value.