IC Fabrication Using Electron-Beam Technology.

The object of this program was to develop a manufacturing capability for standard bipolar circuits of conventional design using existing e-beam direct writing equipment. In particular, a pilot-line demonstration of significant yields of conventional 4-5-micrometer design rule integrated circuits which were fully tested to military specifications for performance, quality and reliability was of paramount importance. Achievement of this objective then establishes a baseline for direct e-beam writing in production and provides a significant stepping stone for implementation of e-beam technology in VLSI circuit fabrication. The vehicle used for this demonstration was a standard TTL 256-bit bipolar RAM SN74S201A using a single-level metal, junction isolated, Schottky clamped bipolar process. Emphasis was placed on utilizing a new class of high-speed electron resist TI-309 and TI-313 in combination with selective plasma etching techniques in order to establish economical next generation VLSI processes. A vector scan, laser controlled e-beam direct writing system developed with fully automatic slice alignment was used for patterning of these devices. To determine that e-beam direct writing yields devices with no degradation in performance of reliability, optically patterned split lot controls were fabricated in parallel and used for comparative testing. This program has established an e-beam lithography baseline process utilizing high-speed electron resists and plasma etching techniques for fabrication of bipolar microcircuits.