Raytek Gmbh

Applied Process Technology, Inc.

James T Christol

Herbert L Berman

John S Burchard

Michael R Jacobs

Hand-held instrument for measuring the temperature of a target without contact with the target. The instrument utilizes a microprocessor and a digital display to calculate and indicate different temperature functions. Compensation is included for the effects of emissivity and ambient temperature changes which otherwise could result in inaccurate readings. Temperature trend direction liquid crystal arrow(s) actuated by the microprocessor are included in the display.

Hand-held digital temperature measuring instrument

A method for detecting the end point of etching wafers and the like by reflective means. Typically, a detected reflectance signal will have a threshold level representing a lack of substantial etching, a dip in the threshold level representing the commencement of etching and an inflection level representing a maximum rate of light amplitude change. The present method involves subtracting the inflection level from the threshold level and taking a predetermined fraction of the resultant level to define a second threshold level further in the etch cycle which anticipates the end of the cycle. By observational experience, the predetermined fraction can be determined. As soon as the second threshold level is reached, brakes are applied to the etching process so that etching will cease shortly after the predetermined level has been identified. In this manner, the actual end of etching will coincide with the attainment of a desired etching condition, such as removal of a layer of undesired metalization, without significant overshoot.

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Cupertino, CA, United States of America

James T Christol