Integrated Process Equipment Corporation

Paul J Clapis

Sherman K Poultney

George J Gardopee

Joseph P Prusak

Keith E Daniell

A method for co-registering a semiconductor wafer (14) undergoing work in one or more blind process modules (10), (12) requires a means (16), (18) for consistently and repeatably registering the semiconductor wafer (14) to each process module (10), (12). Given this consistent and repeatable singular wafer registration means (16), (18), the location of the coordinate axes of each process module (10), (12) is determined with respect to the position of the semiconductor wafer (14) that is registered therein. The present invention method provides three approaches for determining the location of these axes: (1) an absolute location of the axes, (2) a relative location of the axes using one blind process module (10) to measure the position of a pattern etched into the semiconductor wafer (14) with another blind process module (12), and (3) a relative location of the axes using one blind process module (10) to measure surface or layer thickness characteristics in the semiconductor wafer (14) as modified by wafer processing. Regardless of which approach is followed, the determination of the location of the coordinate axes in each process module (10), (12) is an effective co-registration of the semiconductor wafer (14).

Method for co-registering semiconductor wafers undergoing work in one or

The thicknesses of a first layer and of a second layer on a semiconductor wafer can be measured together by assuming that the second layer has a substantially uniform thickness. The thicknesses are measured by measuring reflectivity as a function of wavelength at a plurality of points on the wafer to provide a plurality of signatures, comparing each signature with signatures from libraries of theoretical signatures by calculating an error value associated with each signature; and determining the minimum error value. Each library is based upon a unique assumed thickness of the second layer. Thus, the thickness of the second layer is determined by identifying the library associated with the minimum error value.

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Sandy Hook, CT, United States of America

Paul J Clapis