Initial results for dose-to-clear reduction using the integrated circuit manufacturing with plasma activated chemical treatment (IMPACT) tool

Williams, Christian Donald

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https://hdl.handle.net/2142/121280 Copy

Description

Title

Initial results for dose-to-clear reduction using the integrated circuit manufacturing with plasma activated chemical treatment (IMPACT) tool

Author(s)

Williams, Christian Donald

Issue Date

2023-07-21

Director of Research (if dissertation) or Advisor (if thesis)

• Ruzic, David N
• Sankaran, R. Mohan

Committee Member(s)

Uddin, Rizwan

Department of Study

Nuclear, Plasma, & Rad Engr

Discipline

Nuclear, Plasma, Radiolgc Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(s)

• atmospheric plasma
• semiconductor

Abstract

Lithographic processes have come a long way over the past couple of decades in an effort to keep up with Moore's law. Despite the many advances that have been made when it comes to the lithography aspect,(sources, optics, etc.) of semiconductor manufacturing, there are still many issues that must be addressed when it comes to the chemicals that are used in this field. This work investigated the viability of an atmospheric plasma jet (in both dielectric barrier discharge and direct-current discharge configurations) as a means to reduce the dose of light necessary to activate the chemically-amplified photoresist such that it is more easily removable through the application of a development solution. Preliminary density-functional theory (DFT) models indicated that there is a weakening of the bonds in a simple pentane structure if there is a negatively charged species that is injected near a polymer structure. Solvated electrons were thought to be the key to inducing this sort of behavior. Preliminary data showed promising results, however the change observed in the dose of light necessary to remove the photoresist were difficult to replicate. While the initial set of results was not able to be replicated, a systematic approach was developed to control and account for as many variables as possible, which will serve as the foundation for future work in the same area of research. Verification that any potential effects that were due only to the plasma and not the gas flow were performed using a rheometer, to ensure that the viscosity was not somehow altered and would therefore lead to a reduction in the film thickness. While slight differences were seen in the viscosity between the gas flow control samples and the treated/reference samples, there was no noticeable effect on the size of the transferred pattern. The side lengths of the hexagons present were measured using a $3$D optical profilometer and then the area of the hexagon was calculated using these measurements, initially using a vacuum ultra-violet (VUV) light source as a stand-in for an extreme ultra-violet (EUV) light source while the tool was being assembled and tested. Once the EUV source was constructed, additional experiments were conducted using it as the lightography source. Because the mask that was used in the initial experiments was no longer usable due to the necessity of a zirconium EUV filter, the measurement technique to compare the treated and non-treated samples was altered such that the amount of photoresist removal was quantified through cross-sectional scanning electron microscope (SEM) images of the coated silicon wafer in conjunction with image measurement software. Future work is proposed for the improvement of the EUV source, as well as other applications in the field of semiconductor manufacturing where the IMPACT tool may have some promise.

Graduation Semester

2023-08

Type of Resource

Thesis

Copyright and License Information

© 2023 CHRISTIAN DONALD WILLIAMS

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