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Research On Immersion System Environment Control And Surface Disposal

Posted on:2008-02-23Degree:MasterType:Thesis
Country:ChinaCandidate:K X JingFull Text:PDF
GTID:2121360242967690Subject:Mechanical and electrical engineering
Abstract/Summary:PDF Full Text Request
Optical lithography has been an industrial workhorse for many decades, reaching a wavelength of 193 nm, which is 45nm lithography node. Immersion lithography has recently emerged as the leading candidate for extending 193nm lithography to the 45nm lithography node and beyond. By immersing the wafer in a high index fluid, lens designs with numerical apertures (NAs) approaching the refractive index of the fluid are possible.In immersion lithography, the air gap that currently exists between the last lens element of the exposure system and the wafer is filled with a liquid that more closely matches the refractive index of the lens. There is a possibility that air bubbles, which represent a refractive index discontinuity, may be present in the liquid within the active exposure region and cause errors in imaging. One potential source of bubble generation is related to the flow of liquid over previously patterned features, or topography, during scanning or filling. With the deposition of the immersion liquid onto the wafer during the scanning process, any residual liquid left on the wafer is a potential defect mechanism. In this paper, the details of a fluid management system were built, and effects from chemical and physical characteristics of wafer surface were discussed both by experimentation and simulation.The first chapter introduced the development of the principle of optical lithography and its presents. Advantages of immersion lithography were presented with concepts and challenges. Searches on fluid management and surface treatment abroad contemporarily for immersion lithography were reviewed. At last, the significance and content of the thesis were presented.The second chapter analyzed the principle of hydrophobia and hydrophile. Then the relationship between static contact angle and imbibition was discussed. And several methods for hard coating were introduced, including advantages and theories of vacuum evaporated filming. Contact angles of coating materials were researched with their coating characteristics.The third chapter firstly summarized various contact angles, and the wafer moving velocity and gas-phase elements effects. The method of contact angle measuring was introduced, with the setup implemented in this paper. Then the measurement results were listed.The fourth chapter analyzed the bubble-trapping and bubble-lifetime during water injection. Simulation method of computational fluid dynamatics (CFD) using volume of fluid (VOF) model was presented. Two dimentional simulations were performed to investigate the effects of contact angle, injection velocity and wafer surface characteristics. At last, meniscus characteristics were discussed.In the fifth chapter, details of a fluid management system was designed and built according the requirement from immersion unit with gas-seal. The setup devices and control method were presented.The sixth chapter reached a conclusion and suggested the future research work.
Keywords/Search Tags:immersion lithography, surface treatment, contact angle, hydrophilicity, surface characteristics, FLUENT, simulation, air bubble
PDF Full Text Request
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