Dry etching procedure
AssigneeAmerican Telephone and Telegraph Company, AT&T Bell Laboratories
InventorRonald J. Schutz
Life of this patent
Estimating the term…
Abstract
The presence of material deposited on the sidewall during device fabrication utilizing plasma-effected etching of semiconductor materials has significant consequences in the properties of these devices. It has been found that such depositions lead to a sidewall slope that, among other things, in turn produces linewidth loss. Additionally, the presence of a sloped masking material, e.g., a photoresist or sidewall deposit, produces further undesirable results.
Claims12
A process for fabricating a device comprising the steps of forming a resist mask on a substrate, etching said substrate to form a plurality of etch pits defining a plurality of features that are designed to have a desired linewidth by inducing reaction of said substrate with energetic species, and completing said device, wherein redeposition of material on the sidewalls of said etch pit occurs during said etching and wherein said process includes a step comprising locally compensating for the effect of said redeposition on the conformation of said sidewall by providing a processing environment for at least one of said features that differs from at least one of said features to aid in maintaining said linewidth.
A process for fabricating a device comprising the steps of forming a resist mask on a substrate, etching said substrate to form a plurality of etch pits defining a plurality of features by inducing reaction of said substrate with energetic species, and completing said device, wherein redeposition of material on the sidewalls of said etch pit occurs during said etching and wherein said process includes a step comprising contacting, when said redeposited material presents a barrier to isotropic etching in said substrate, said etchant species with said resist mask so that the angle formed between a) a tangent to said resist mask at the point said resist mask intersects the substrate and b) a perpendicular to said substrate at said point is less than arctan (.sub.y.sup.x), where x is the horizontal rate of said redeposition at said point and y is the etch rate of said substrate whereby the linewidth defined by said mask is essentially maintained.
A process for fabricating a device comprising the steps of forming a resist mask on a substrate, etching said substrate to form a plurality of etch pits defining a plurality of features by inducing reaction of said substrate with energetic species, and completing said device, wherein redeposition of material on the sidewalls of said etch pit occurs during said etching and wherein said process includes a step comprising limiting, when said redeposited material presents a barrier to isotropic etching in said substrate, the contact angle between the momentum direction of said etchant species and a tangent to said redeposited material at all points on said resistant redeposited material serving to mask said sidewalls so that said contact angle is less than arctan (.sub.z.sup.x), where z is the etch rate of said resistant redeposited material in a direction parallel to said etchant species momentum direction and where x is the horizontal rate of deposition at said point whereby anisotropy is maintained without an excessive decrease in etch rate.
Dependencies are inferred from the claim text.