International Business Machines Corporation

Lawrence Andrew Kropp

John C Forster

David Stanasolovich

Jyothi Singh

Tina J Cotler

Marc Jay Weiss

Dennis Sek-On Yee

A homogeneous marker is formed, possibly by the adsorption of trace amounts of an ambient material such as carbon monoxide gas, at a surface of a deposited material when the plasma in momentarily interrupted during plasma enhanced chemical vapor deposition or other deposition processes involving the presence of a plasma. When the deposited material is etched, the resulting crystal dislocations or adsorbed gas is detected as a marker by optical emission spectroscopy techniques. The accuracy of an end point determination of the etching process can be increased by providing a sequence of such markers within the bulk or volume of the deposited material. The markers, being merely an interface such as a slight crystal dislocation in otherwise homogeneous material, do not affect the electrical, chemical or optical properties of the remainder of the predetermined deposited material and thus the homogeneity of the deposited material is not significantly affected.

Precise endpoint detection for etching processes

A non-intrusive means and method are disclosed for monitoring the interelectrode gap in a reaction chamber containing a pair of variably spaced, nominally parallel reaction-sustaining electrodes. An example is given in which the chamber is a plasma enhanced chemical vapor deposition chamber. The electrodes are treated as a parallel plate capacitor in order to measure the gap therebetween as well as the parallelism of the electrodes without requiring that the chamber be opened. A calibration curve is prepared by ascertaining known values of gaps by use of spacer gauges and then measuring and storing the corresponding values of the gaps and the capacitances. Once the calibration curve is established and stored, the spacing between the electrodes can be checked from time to time, as needed, without opening the chamber. It is only necessary to measure the capacitance existing and then refer the measured value to the stored values to read out the corresponding gap value. By making several capacitance measurements, a new curve can be made from time to time which can be compared as to slope with the stored calibration curve to check the parallelism of the electrodes.

Reaction chamber interelectrode gap monitoring by capacitance measurement

Growing community of inventors

Pleasant Valley, NY, United States of America

Lawrence Andrew Kropp