Investigation of electron beam lithography with the low-temperature short-interval development technology
Date Issued
2016
Date
2016
Author(s)
Chung, Cheng-Huan
Abstract
Lithography is the key technology in integrated circuits manufacturing process, and the improvement of it is the main reason that Moore''s law can keep going. The rapid development of semiconductor industry and chips can become smaller and cheaper are closely related to the progress of lithography.For a long time, optical lithography is the mainstream in semiconductor industry, it is superior to other lithography method because of its mass production with high speed and low cost. However, with chips size become smaller and smaller optical lithography has reached its limit, it is necessary to investigate a new method for lithography, E-beam (Electron Beam Lithography) and EUV (Extreme Ultraviolet Lithography) are the main research direction lithography method in the future. In this thesis, we focus on how to reduce the proximity effect in electron beam lithography. We propose three method to solve proximity effect, including changing the resist, shortening the developing time, and reducing the developing temperature. After the experiment of changing resist, we compare the pros and cons in different resist, and we choose the most suitable resist for our subsequent experiment. Then we use the electron beam system to design single spot experiment and observing the diameter broadening of spots by changing exposure dose and developing condition. Through the experiment result, we found that by combining the short time and low temperature development we can reduce the proximity effect substantially. We further use the experiment result and traditional electron scattering research to derive our model for short interval development, then we fitted our model with experiment data and found that it fitted very well and every coefficient in our model have a good physical meaning. We next use our model to write different pitch lines pattern, and succeed in making 9nm small line width and 30nm small pitch line patterns, and also proved our single spot experiment result can apply to write line patterns and have the same trend. Finally, we use reactive ion etch and evaporation to transfer our pattern to silicon substrate successfully.
Subjects
E-beam lithography
proximity effect
developing rate
electron scattering
small line width pattern
pattern transfer
Type
thesis
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