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Automatic Batch End-Point Detector for Dry Processing

IP.com Disclosure Number: IPCOM000044156D
Original Publication Date: 1984-Nov-01
Included in the Prior Art Database: 2005-Feb-05
Document File: 2 page(s) / 50K

Publishing Venue

IBM

Related People

Bergendahl, AS: AUTHOR [+4]

Abstract

The following techniques employ emission spectroscopy for automatic batch end-point detection for thin films: 1. The algorithm used to generate the curve in Fig. 1 must be one where it has empirically been found that the end point is at the inflection point 11 and not at the stabilization point 12. Three examples of algorithms that generate the required curves are (where I = relative intensity or area of peak): A. IPK1 - IPK2 monitored vs. time. IPK1 is defined as a peak that is sensitive to the etch while IPK2 is not. B. IPK1 - Io monitored vs. time. IPK1 is defined as a peak that is sensitive to the etch. Io is the most immediate previous sample of IPK1 . C. (IPK1 - IPK2)n monitored vs. time. IPK1 is defined as a peak that increases/decreases with etching while IPK2 is a peak that decreases/increases with etching.

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Automatic Batch End-Point Detector for Dry Processing

The following techniques employ emission spectroscopy for automatic batch end-point detection for thin films: 1. The algorithm used to generate the curve in Fig. 1 must be one where it has empirically been found that the end point is at the inflection point 11 and not at the stabilization point 12. Three examples of algorithms that generate the required curves are (where I = relative intensity or area of peak): A. IPK1 - IPK2 monitored vs. time. IPK1 is defined as a peak that is sensitive to the etch while IPK2 is not. B. IPK1 - Io monitored vs. time. IPK1 is defined as a peak that is sensitive to the etch. Io is the most immediate previous sample of IPK1 . C. (IPK1 - IPK2)n monitored vs. time. IPK1 is defined as a peak that increases/decreases with etching while IPK2 is a peak that decreases/increases with etching. The quantity IPK1 - IPK2 is raised to the exponential power of n > 3. 2. A microprocessor in situ determines the first derivative (WI/Wt) of the end point of the curve in Fig. 1. This is illustrated in Fig.
2. It is required that the first derivative (WI/Wt) take place while the scanning process takes place. Since the end point of the algorithms used has been determined to be at the inflection point 11, the first derivative would indicate the end point when WI1 ' Wt1 is less than WIa ' Wt2 or where there is a downward slope. Then, the microprocessor very quickly deactivates the etch tool without an...