CAREER: Materials and Processes for Microlithography, Patterning and Surface Modification (Nanoscale)

Georgia Tech Research Corporation, Atlanta GA

Investigators

Abstract

ABSTRACT CTS-9985196 Clifford L. Henderson Georgia Institute of Technology Microlithography, the process used to print circuit elements in Microelectronic devices, is the key technology driver for the semiconductor industry. Current microlithographic technologies are reaching the limits of their resolution (-180 ran) and new materials and processes must be developed to enable continued progress in the industry. Failure to develop more advanced, higher resolution patterning processes would result in a devastating of semiconductor devices. A two pronged approach to solving this problem will be followed by providing a progression of materials processes that can be pattern features down below 100 nm in size. The first part of the project deals with research directed at improving current photoresist (the photosensitive polymeric materials) materials to provide higher resolutions. One of the fundamental problems with developing better photoresists and processes based on current materials is the difficulty associated with measuring the physical properties of the photoresist that govern its lithographic performance, i.e. concentration of acid generated due to exposure and diffusivity of this acid in the polymer matrix. Without this knowledge, it is difficult to rationally design improved materials and processes. This work will develop a new, revolutionary technique based on measuring the capacitance of polymer coated interdigitated electrode (IDE) capacitors which can be used for quantifying the extremely small acid concentrations and diffusion of this acid within the photoresist film. This technique will be calibrated against other acid measurement techniques including microtitration methods. The effect of photoresist composition and processing on the accuracy and sensitivity of this technique will be evaluated. The methods and technology developed in this work will be transferred to industry through operations with industry, including a collaboration with SEMATECH (an R&D consortium for the industry). This technique will make it possible for the first time using non-invasive, nondestructive techniques to extract the physical parameters required to develop predictive models for the performance of photoresists. These models can then be used to guide the rational design of improved photoresist materials and processes that will be capable of resoining features as small as 130 nm. The extension of current lithographic photoresist materials and processes is not sufficient to achieve resolutions below approximately 130 nm. To achieve these resolutions it will be necessary to change from current optical exposure systems (193 nm and 248 nm light) to so-called "Next Generation Lithography" tools (157 nm or 13 nm light). This conversion represents a substantial challenge since the current photoresist materials used at higher wavelengths will not function due to their strong absorbance at these vacuum-UV wavelengths. Thus, new photoresist materials and processes must be developed, The goal of the second part of the proposed research is to develop a novel surface imaging photoresist material based on the polymerization of aromatic monomers at solid surfaces using surfacebound photosensitive radical initiators. These materials will enable pattern generation down to molecular length scales. This project will demonstrate the use of such methods to pattern sub-100 nm features and develop a fundamental understanding of the mechanisms and system parameters that control the performance of these materials. The deposition of covalently linked polymer thin films on surfaces allows for the control of the complete physiochemical nature of surfaces over molecular length scales. Thus, in addition to semiconductor applications, these materials have a number of uses in bioengineening, integrated optics, and other areas that will be explored. Four main educational innovations will be pursued: (1) development of new classes, (2) modification of existing courses to include non-traditional interdisciplinary Problems, (3) implementation of internet based teaching and teaching evaluation tools, (4) creation of a diverse, interdisciplinary research experience for students. Some of the specific goals of these activities are to: (1) present students with opportunites to learn about frontier fields for chemical engineers including microelectronics, (2) engage the active participation of the semiconductor industry in teaching activities, (3) demonstrate the application of fundamental engineering principles in the analysis of non-traditional problems, and (4) strengthen interest and involvement of under-represented groups in microelectronics.