International Business Machines Corporation

Bernard Auda

Roland Chanclou

An apparatus (20) for monitoring the trench formation process in a silicon wafer on a full in-situ and on-line basis. The apparatus includes two spectrometers (30A, 30B) for viewing the plasma used in the trench etching process at zero and normal angles of incidence with respect to the plane of the wafer, respectively. Both spectrometers are tuned to detect the radiation associated with a selected specie present in the plasma. Based on information contained in the output signals of the spectrometers, the depth D of the trench and the thickness Th and rate of deposition of the redeposited SiO.sub.2 layer are computed in real time. When the computed depth D matches a final depth of parameter, the trench formation process is terminated.

Method and apparatus for in-situ and on-line monitoring of trench

A follow-up system for monitoring the etching process in RIE equipment. A spectrometer is used in an interferometric mode for accurate thickness measuring to produce high-resolution and reproducible patterns in a layer of etchable material formed on a substrate.

Follow-up system for etch process monitoring

In a dry etching equipment, a variable gas mixture composition provides etch and ash simultaneously. For example, when a SiO.sub.2 /phospho silicate glass composite insulating layer with a respective thickness of about 300 and 600 nm masked by a patterned photoresist layer is to be etched, a CHF.sub.3 /O.sub.2 gas mixture may be used with the following steps:

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Linas/Montlhery, France

Bernard Auda