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Recent advances in optical lithography driven by the use of mid-UV radiation (365/313 nm) require resists optimized to operate effectively at these wavelengths. New positive resist formulations have been developed to meet this need. DYNALITH resists X-1608 and X-1605 display enhanced sensitivity toward mid-UV exposure. Comparison data vs. standard and deep UV resists are presented. A variety of exposure modes, including projection and contact, have been investigated. DYNALITH Positive Resist X-1608 is based on a novolac and 2,1,4 quinone diazides which are optimized for resist performance. This new resist 11.as sensitivity which is improved over standard resists in mid-UV exposures. Sensitivity of 30-70 mJ/cm is demonstrated at 313 nm and 365 nm. X-1608 mid-UV resist demonstrates submicron imaging capability with high contrast and wide process windows. DYNALITH Positive Resist X-1605 is based on a novolac and the more standard 2,1,5 quinone diazide. This resist formulation provides an overhung or reentrant sidewall profile with the use of standard processing steps. The absence of the necessity of a chlorobenzene soak coupled with the appearance of sidewall profiles as displayed indicates the X-1605 resist to have application for metal lift off processing. The suitability of consistent resist sidewall profiles for metal lift off provides an application for X-1605 resist in GaAs lithography. A control of the degree of curvature and overhang displayed by the resist profiles relative to formulation is described. Process stability of soft bake and exposure is presented for DYNALITH X-1608 on mid-UV projection aligners. Dry etch data relating resists X-1608 and X-1605 to standard resists is presented. Statistical process control (SPC) is an important control method as production requirements shrink to the one micron regime. The use of process control (X) and range charts (R) generated for coating DYNALITH X-1608 resist is presented. SEM photos characterizing the resists and certain process latitudes are presented. Analytical techniques, such as GPC and C13 NMR, assisted the characterization of structure/performance relationships.
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