A new type of microscope (DDM) has been applied to submicron process development at the Fairchild Research Center. This high resolution video microscope produces an image which is the superposition of a dielectric discontinuity (phase contrast) and an absorptive optical image. With this instrument a Sparrow's resolution of 0.08 μm has been achieved at magnifications from 1150 times to 18,000 times. VIA and contact clearing have been observed from 0.1 μm to 1.4 μm at aspect ratios of up to 3:1. CD measurements have been made on both latent images and developed images and the results used to optimize the exposure energy for an I-line stepper. The DDM has also been used to visualize defects which are not visible with conventional microscopy. Both metallic and dielectric contaminant films have been detected and a submicron dielectric sidewall has been visualized on an advanced interconnect system. Material deposited during development using the MIMMI process has been observed. A simplified phase contrast transition theory is presented and applied to the observations.