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Extramural Research

Dry Lithography: Environmentally Responsible Processes for High Resolution Pattern Transfer and Elimination of Image Collapse using Positive Tone Resists

EPA Grant Number: R829586
Title: Dry Lithography: Environmentally Responsible Processes for High Resolution Pattern Transfer and Elimination of Image Collapse using Positive Tone Resists
Investigators: DeSimone, Joseph M.
Institution: University of North Carolina at Chapel Hill
EPA Project Officer: Richards, April
Project Period: November 1, 2001 through November 1, 2004
Project Amount: $347,898
RFA: Technology for a Sustainable Environment (2001)
Research Category: Nanotechnology , Pollution Prevention/Sustainable Development


With the award of the NSF Science and Technology Center for Environmentally Responsible Processes and Solvents in 1999 (http://www.nsfstc.unc.edu Exit EPA icon) and prior partnerships formed with industrial members of the Kenan Center for the Utilization of Carbon Dioxide (CO2) in Manufacturing (http://www2.ncsu.edu:8010/champagne/ Exit EPA icon), research endeavors by Joseph DeSimone, the principal investigator of this proposal, have made significant headway in replacing hazardous solvents and water with environmentally responsible CO2. In particular, this research has helped establish the scientific and engineering principles necessary for the commercialization of CO2 in the manufacture of TeflonTM as well as professional garment care (dry cleaning). It now seems feasible to drive this proposal and extend the benefits of CO2-based processes to the microelectronics industry, taking advantage of the low surface tension and viscosity of CO2 for applying and removing extremely thin films.

The focus of this proposed research is to utilize liquid and supercritical carbon dioxide to integrate the film deposition and removal processes in positive tone lithography with the chemistry to totally eliminate the use of solvents and water. This integrated approach based on CO2 will convert lithography from an inherently "wet" process to a "dry" process. Such a dry process would also eliminate image collapse, enable the "solvent free" coating of large area wafers, eliminate ion contamination associated with water usage during development, and ultimately allow lithographic processes to be designed for the first time into cluster tool approaches.


The research includes environmentally friendly synthesis of advanced photoresists, the in situ and ex situ characterization of the photoresist film formation process, the physical and chemical characterization of the resists relative to processing in CO2, and the physical and chemical characterization of the resists relative to resist performance. Emphasis is on 193 and 157 nm resists.

Expected Results:

Much of what is learned about environmentally friendly synthesis, pattern development avoiding collapse, and in situ and ex situ process characterization will be useable for associated patterning technologies while substantially and specifically advancing the practice of 157 nm lithography. The team of researchers for this proposal is a multi-institutional, multi-disciplinary team of scientists and engineers that are qualified to provide sufficient process information to the microelectronics and photonics industry for the rapid implementation of the CO2 based process for advanced technologies.

Publications and Presentations:

Publications have been submitted on this project: View all 22 publications for this project

Supplemental Keywords:

photoacid generators, fluoropolymers, spin coating., RFA, Scientific Discipline, Sustainable Industry/Business, Chemical Engineering, cleaner production/pollution prevention, Environmental Chemistry, Sustainable Environment, Technology for Sustainable Environment, Economics and Business, Environmental Engineering, supercritical carbon dioxide (SCCO2) technology, in-process waste minimization, cleaner production, clean technologies, green design, high resolution pattern transfer, environmentally benign solvents, alternative materials, supercritical carbon dioxide, alternative solvents, engineering, solvent substitute, microelectronics, environmentally benign alternative, dry lithography, pollution prevention, green chemistry

Progress and Final Reports:
2002 Progress Report
2003 Progress Report
Final Report

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.

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