International Business Machines Corporation

Linda M Ephrath

Gary S Selwyn

Victor J Silvestri

Denny D Tang

Geraldine C Schwartz

Reid S Bennett

Laser induced fluorescence is utilized to detect and control the reactive ion etch-through of a given layer in a wafer by detecting a large change in the concentration of a selected minor species from the wafer in the etching plasma. This selected minor species must be present in a significantly different concentration in the etched given layer compared to adjacent layers in the wafer in order to provide a proper endpoint detection. In one embodiment, when the large change in the selected minor species concentration is detected, then the RF electrodes for the reactor are automatically de-energized.

Trench etch endpoint detection by LIF

Isolation regions in a semiconductor substrate are formed by covering at least one of the surfaces within a trench within the substrate with non-nucleating material, providing a layer of nucleating material on at least one surface of the non-nucleating material and then filling the trench with polycrystalline silicon or epitaxial silicon or both.

Method of filling trenches with silicon and structures

Reactive Ion Etching (RIE) apparatus which provides for uniform etching of substrates regardless of their position on a cathode is disclosed. The RIE apparatus utilizes a perforated anode. These perforations are interlaced, intersected or partially blocked with various configurations of conductive elements. Concentric circle, starburst, spiral arm and spiral configurations may be interlaced with the perforations in the anode to obtain uniform etching of substrates regardless of their radial position on the cathode. With all these configurations, the common factor is that the interlaced configurations intersect more perforations near the center of the anode or catcher plate than are intersected at greater radial distances.

Reactive ion etching apparatus with interlaced perforated anode

A silicon oxide, nitride, and/or oxynitride surface on a substrate is selectively etched at a rate greater than that of the substrate by a reactive ion etching employing a gaseous mixture containing a fluorocarbon and a second gas capable of supplying hydrogen.

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Danbury, CT, United States of America

Linda M Ephrath