Synthesis Of Ultra High Molecular Weight Polymethyl Methacrylate And Application In Electron Beam Photoresust

Electron beam lithography(EBL)is an extremely important technology in the manufacture of high-performance electronic devices and mask production in the semiconductor industry.It is different from other lithography technologies.It can directly write without a mask.Resist is an indispensable part of electron beam lithography technology,and polymethyl methacrylate(PMMA)has become a the most commonly used and extremely high-resolution e-beam resist,and its resolution and etch resistance can be improved by increasing the molecular weight of polymethyl methacrylate(PMMA).In this paper,ultra-high molecular weight polymethyl methacrylate was prepared by suspension polymerization,and the effect of post-treatment on its purity was studied.It was further formulated into an electron beam resist,and its use in spin coating,exposure,development,etching,etc.was studied.performance in craftsmanship.The specific research contents are as follows:Firstly,ultra-high molecular weight polymethyl methacrylate was prepared by suspension polymerization.Different monomer/water ratios,types and amounts of initiators,monomer dripping methods,polymerization temperature,dispersant dosage,stirring speed,The effects of reaction time and other factors on the molecular weight,polydispersity coefficient,glass transition temperature and other properties of the prepared PMMA were studied,and the molecular weight regulation rules and methods were obtained.The polymethyl methacrylate with weight average molecular weight(MW)in the range of 4-198×10~4 Da and dispersibility coefficient(PDI)in the range of 1.7-4.5 was prepared.Its molecular weight and distribution satisfy the requirements of being used as electron beam photoresist.requirements.Secondly,the prepared high-molecular-weight PMMA was subjected to post-treatment by water washing,acid washing,alcohol washing,reprecipitation,drying,etc.,and the effect of the post-treatment process on the residual single,gold impurities and moisture content in PMMA was studied,so as to achieve Purity requirements for e-beam photoresists.Finally,the super purified were molecular weight is about 73×10~4 Da PMMA dissolved in ethyl lactate,made the electron beam resist,and spin in the ultra clean room,before baking,exposure,development and hard baked,etching process,such as the preparation of PMMA by electron beam resist from adhesion,resolution,contrast and sensitivity evaluation,It is found that the self-made PMMA photoresist is very close to the foreign pm MA-950K electron beam photoresist with AR-P 672 in resolution,sensitivity and contrast,and it is expected to realize the localization of PMMA-950K photoresist.