Paper
3 September 1999 Deformation and stress in PMMA during hard x-ray exposure for deep lithography
Nicolai A. Moldovan
Author Affiliations +
Proceedings Volume 3875, Materials and Device Characterization in Micromachining II; (1999) https://doi.org/10.1117/12.360466
Event: Symposium on Micromachining and Microfabrication, 1999, Santa Clara, CA, United States
Abstract
The availability of high-energy, high-flux, collimated synchrotron radiation has extended the application of deep X-ray lithography to thickness values of the PMMA resist of several millimeters. Some of the most severe limitations come from plastic deformation, stress, and cracks induced in PMMA during exposure and development. We have observed and characterized these phenomena quantitatively. Profilometry measurements revealed that the PMMA is subjected either to local shrinkage or to expansion, while compression and expansion evolve over time. Due to material loss and crosslinking, the material undergoes a shrinkage, while the radiation-induced decomposition generates gases expanding the polymer matrix. The overall dynamics of the material microrelief and stress during and after the exposure depend on the balance between compaction and outgassing. These depend in turn on the exposure conditions (spectrum, dose, dose rate, scanning, temperature), post-exposure storage conditions, PMMA material properties and thickness, and also on the size and geometry of the exposed patterns.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Nicolai A. Moldovan "Deformation and stress in PMMA during hard x-ray exposure for deep lithography", Proc. SPIE 3875, Materials and Device Characterization in Micromachining II, (3 September 1999); https://doi.org/10.1117/12.360466
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Cited by 4 scholarly publications.
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KEYWORDS
Polymethylmethacrylate

Polymers

Diffusion

Hard x-rays

X-rays

Foam

Lithography

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