International Business Machines Corporation

Robert W Sweetser

Donald M Kenney

William J Cote

Michael A Leach

Michael L Kerbaugh

Donald G Chesebro

Jeffrey A Robinson

A conformal organic layer is used to define spacers on the sidewalls of an organic mandrel. The organic layer (e.g., parylene) can be deposited at low temperatures, and as such is compatible with temperature-sensitive mandrel materials that reflow at high deposition temperatures. The conformal organic material can be dry etched as the same rate as the organic mandrels, while being resistant to wet strip solvents that remove the organic mandrels. This series of etch characteristics make the organic mandrel-organic spacer combination compatible with a host of masking applications.

Process for defining organic sidewall structures

A method of enhancing first order alignment marks formed in the respective layers of a processed semiconductor wafer in which critical masking steps are carried out. After a given mark is formed, it is tested for visual contrast. If the contrast is insufficient to provide adequate alignment, a block mask is formed on the critical mask. The block mask exposes all of the alignment target areas and protects the product regions of the wafer, and the critical mask only exposes the mark to be enhanced. The mark is then etched for a time period which is a function of the measured visual contrast. This method of selectively enhancing selected ones of the first order alignment marks greatly enhances the utility of such marks, increasing the accuracy of critical masking steps.

Visibility enhancement of first order alignment marks

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Essex Junction, VT, United States of America

Robert W Sweetser