Method and apparatus for measuring etch uniformity of a semiconductor wafer
AssigneeApplied Materials, Inc.
InventorsMelisa J. Buie, Leonid Poslavsky, Jennifer Lewis
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Abstract
A method and apparatus for performing in situ measurement of etch uniformity within a semiconductor wafer processing system. Specifically, the apparatus and concomitant method analyzes optical emission spectroscopy (OES) data produced by an OES system. The analysis computes the first derivative of the OES data as the data is acquired. When the data meets a particular trigger criterion, the value of the first derivative is correlated with a particular uniformity value. As such, the system produces a uniformity value for a semiconductor wafer using an in situ measurement technique.
Claims6
A method for measuring uniformity of a surface of a wafer as a result of an etching process comprising the steps of:
- acquiring data indicating etch progression, wherein said data represents an intensity of an emission at a monitored wavelength of light;
- defining a trigger criterion corresponding to a particular value of said data to form a trigger point;
- producing, as said data is acquired, a first derivative of said data as a first derivative value, wherein said first derivative value is produced by X 2 - X 1 Δ T
- where X1 is a data point in said data, and X2 is a data point and ΔT is a time duration elapsed between acquisition of the and data points, said trigger criterion is a peak of said first derivative;
- and
- generating, when said trigger criterion is attained by said data, a uniformity value representing the uniformity of the surface of the wafer by directly correlating said first derivative value to said uniformity value.
Dependencies are inferred from the claim text.