Abstract: A method is disclosed for fabricating patterned conductive lines which are self-aligned with underlying contacts windows. A layer of a photosensitive material such photoresist is formed over a dielectric layer. The photoresist layer is processed to have fully developed areas corresponding to contact windows, partially developed areas corresponding to the patterned conductive lines and undeveloped areas which correspond to field areas where the entire dielectric layer is maintained. The dielectric layer is preferably a compound dielectric layer to reduce interlevel shorts. Through the use of selective etch steps, the compound dielectric layers aid in the formation of the patterned conductive line and contact window structure. A series of reactive ion etch (RIE) steps are performed. The first RIE step, highly selective to dielectric material as compared to photoresist, etches the fully developed areas at least partially through the dielectric thickness.

Abstract: The process is based upon applying a layer of release agent which is a solution of a polysulfone constituent and a dye, applied to the surface of a polysilicon layer. Thereafter, the photoresist layer can be applied on top of the release agent layer. Then, the photoresist can be optically exposed and developed and its alignment measured. If the alignment of the resultant photoresist structures is found to be incorrect, rework can be easily accomplished by dissolving the release agent in a suitable solvent. This allows the existing photoresist structures to be removed. Then the rework cycle can continue by applying a new layer of the release agent and dye solution and followed by a new photoresist layer. If the original photoresist layer or the reworked photoresist layer is found to have been properly aligned, then the normal processing steps can continue. The process also provides for an improved control over back reflected and diffracted light during the optical exposure step.