| Summary: | 碩士 === 國立成功大學 === 工程科學系專班 === 98 === GaAs semiconductor is an important component in wireless and optical fiber communications. Over 60% of GaAs’s IC chips are used in mobile power amplifiers worldwide. Hence GaAs plays an important role in mobile power amplifier components. This research uses negative PR resists for the pHEMT gate photolithography process development to make the process stable and to increase the yield.
From the photolithography process principle, as negative PR resist exposure energy gets smaller, the thickness of PR becomes smaller after developing (i.e. larger PR resist thickness loss);gate ADM CD also gets larger. Besides, by changing the exposure map,the exposure throughput is increased and the locally defocusing issue of the wafer edge ugly dies is reduced. In addition, by changing the process step after exposure bake, the Gate ADM CD is greatly influenced. This study found the characteristics difference of negative PR resists affected by the process steps. By following the rules obtained for the development of new gate process, the process development speed can be reduced and the process stability can be improved.
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