1 February 1979 Development of a Two-Step E-Beam Lithography Process For Submicron Surface Acoustic Wave (SAW) Device Fabrication
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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.
D. B. MacDonald, D. B. MacDonald, C. F. Shaffer, C. F. Shaffer, T. G. Blocker III, T. G. Blocker III, R. C. Vail, R. C. Vail, } "Development of a Two-Step E-Beam Lithography Process For Submicron Surface Acoustic Wave (SAW) Device Fabrication," Optical Engineering 18(1), 180153 (1 February 1979). https://doi.org/10.1117/12.7972319 . Submission:


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