Pattern detection for integrated circuit substrates

A method for analyzing a substrate, the method comprising the steps of:

• a) specify a subset of all test site locations on the substrate,
• b) select a desired number of candidate test site locations from within the subset of test site locations on the substrate,
• c) while selecting one of the candidate test site locations and holding all others of the candidate test site locations as fixed, determine a new location for the selected one of the candidate test site locations, which new location increases a test sensitivity to at least one predetermined pattern, as estimated by a trace of a variance-covariance matrix,
• d) repeat step c for each candidate test site location in the subset of test site locations to produce a finalized set of candidate test site locations, until a desired end point is attained,
• e) sense characteristics of the substrate at the finalized subset of test site locations, and
• f) analyze the sensed characteristics to determine whether the sensed characteristics indicate the predetermined pattern on the substrate.

A method for analyzing a substrate, the method comprising the steps of:

• a) specify a subset of all test site locations on the substrate,
• b) select a desired number of candidate test site locations from within the subset of test site locations on the substrate,
• c) while selecting one of the candidate test site locations and holding all others of the candidate test site locations as fixed, determine a new location for the selected one of the candidate test site locations, which new location increases a test sensitivity to at least one predetermined pattern, as estimated by a trace of a variance-covariance matrix,
• d) repeat step c for each candidate test site location in the subset of test site locations to produce a finalized set of candidate test site locations, until a desired end point is attained,
• e) sense characteristics of the substrate at the finalized subset of test site locations, and
• f) analyze the sensed characteristics to determine whether the sensed characteristics indicate that the predetermined pattern on the substrate has changed by at least a given amount.