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Optical Engineering

Development of a Two-Step E-Beam Lithography Process For Submicron Surface Acoustic Wave (SAW) Device Fabrication
Author(s): D. B. MacDonald; C. F. Shaffer; T. G. Blocker III; R. C. Vail
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Paper Abstract

A two-step fabrication process was developed which has produced previously unobtainable high frequency surface acoustic wave (SAW) devices. In addition, the design-to-test cycle time has been shortened significantly to allow an effective interactive design procedure. The SAW structure places some of the most stringent precision requirements on current electron-beam lithography, since finger placement errors are directly related to phase errors in the electrical performance of bandpass or pulse compression filters. A form of double precision is implemented in the interface software to enable successful patterning of the monotonic variation in line width from less than 0.4 pm to more than 0.9 pm required for a 1 to 2 GHz pulse compressor. Compensation for proximity effects due to the electron beam profile was also implemented. Alignment accuracy within a field is controlled to within ±250 A and field placement is accomplished via a laser interferometer controlled stage. Several alternative processes, including direct slice writing, reverse liftoff, and x-ray lithography are compared. Once the E-beam master is generated, large area contact replication is achieved using a modified conformable mask printer. This process has extended the range of SAW device performance beyond 2 GHz in a fundamental mode which, represents a significant advancement in microfabrication. Three-day turnaround from design to packaged devices was demonstrated using this technique.

Paper Details

Date Published: 1 February 1979
PDF: 6 pages
Opt. Eng. 18(1) 180153 doi: 10.1117/12.7972319
Published in: Optical Engineering Volume 18, Issue 1
Show Author Affiliations
D. B. MacDonald, Texas Instruments (United States)
C. F. Shaffer, Texas Instruments (United States)
T. G. Blocker III, Texas Instruments (United States)
R. C. Vail, Texas Instruments (United States)

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