Metrology package for electron beam exposure tool evaluation: Application to EBES4

Throughout the stages of electron beam (e‐beam) exposure tool development and application, the machine performance needs to be accurately characterized. A series of tests have been developed and implemented to diagnose and optimize the AT&T in‐house EBES4 system for both mask making and direct wafer writing. The techniques employed for these tests will be described, and the evaluation results and how they lend themselves to machine diagnostics will be illustrated for EBES4.The tests consist of a complement of optical inspection, scanning electron microscopy (SEM) imaging, MARKET analysis, and electrical probe metrology. Optical and SEM techniques served to examine the machine writing characteristics and exposure pattern quality. Partially developed images in positive resists accentuated errors due to improper exposure. Electrical probe metrology was used to quantify and optimize machine accuracy. Compared to conventional optical and SEM measurement techniques, electrical metrology offers the advantages of...