Advanced Micro Devices Corporation

Georg Sulzer

Hartmut Ruelke

Christof Streck

Martin Mazur

Carsten Hartig

Frank Heinlein

By using conventional spacer and etch techniques, microstructure elements, such as lines and contact openings of integrated circuits, may be formed with dimensions that are mainly determined by the layer thickness of the spacer layer. In a sacrificial layer, an opening is formed by means of standard lithography and etch techniques and, subsequently, a spacer layer is conformally deposited, wherein a thickness of the spacer layer at the sidewalls of the opening substantially determines the effective width of the microstructure element to be formed. By using standard 193 nm lithography and etch processes, gate electrodes of 50 nm and beyond can be obtained without significant changes in standard process recipes.

Method of defining the dimensions of circuit elements by using spacer deposition techniques

A low-k dielectric layer stack is provided including a silicon based dielectric material with a low permittivity, wherein an intermediate silicon oxide based etch indicator layer is arranged at a depth that represents the depth of a trench to be formed in the dielectric layer stack. A thickness of the etch indicator layer is sufficiently small to not unduly compromise the overall permittivity of the dielectric layer stack. On the other hand, the etch indicator layer provides a prominent optical emission spectrum to reliably determine the time point when the etch process has reached the etch indicator layer. Thus, the depth of trenches in highly sophisticated low-k dielectric layer stacks may reliably be adjusted to minimize resistance variations of the metal lines.

Low-k dielectric layer stack including an etch indicator layer for use in the dual damascene technique

For determining the quality of an opening formed in a dielectric material layer, a voltage contrast inspection tool is used to produce a voltage contrast image of a test pattern formed in the dielectric material layer. The voltage contrast values of openings may be compared to a reference contrast value or to different openings so as to decide whether or not the opening has a required depth.

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Dresden, Germany

Georg Sulzer