Photo Process for Defining Two Mask Levels in One Step
Original Publication Date: 1988-Oct-01
Included in the Prior Art Database: 2005-Feb-15
A method of making masks for partial exposure of photoresist which is dependent upon varying light intensity and a method of exposure which is dependent upon a light wavelength bandpass filter is reported. Current techniques used to pattern photoresist use one mask process, i.e, resist apply, exposure, develop and etch, for each mask level. Mask alignment is critical in order to maintain registration when multiple masking steps are required. Any self-alignment techniques that can be employed to pattern materials will translate into tighter ground rules and improvements in design densities. Two methods are described for printing two or more mask levels with one exposure step. A profile of the stepped resist structure produced in a single or multiple resist system utilizing either technique is shown in Fig. 1.