Bell Telephone Laboratories

Theodore A Shankoff

Dawon Kahng

The problem of reliably adhering resists to underlying surfaces made of, for example, phosphorus-doped silicon dioxide or silicon nitride is a particularly difficult one. In practice, the use of standard adhesion promoters such as HMDS provides only marginal relief. By baking a relatively thin layer of resist on the underlying layer, a tenacious bond between the thin layer and the underlying surface is achieved. Subsequently, a relatively thick layer of resist is applied and patterned in a standard way. An excellent bond between the thick and thin resist layers results. Subsequent processing of the patterned thick layer leaves the two noted bonded interfaces virtually intact.

Resist adhesion in integrated circuit processing

In the fabrication of semiconductor integrated circuits which include recessed oxide isolation regions (29), formation of the undesired 'bird's head' and 'bird's beak' is avoided by reducing the rate of oxide growth from the sidewalls of isotropically etched recesses (22) while oxide is being grown from the bottoms of the recess regions. A silicon nitride mask (24) formed selectively on each of the sidewalls which has previously been coated with a thin silicon dioxide layer (23) reduces the rate of oxide growth therefrom, so that the oxidized recess regions have substantially planar surfaces after termination of the oxide growth.

Growing community of inventors

Mendham, NJ, United States of America

Theodore A Shankoff