Abstract
We have investigated and report in this paper the factors influencing the deformation caused by the dependence between the absorbed X-ray energy on the resist and the shape of the absorber on the X-ray mask. Based on the measurement of errors that occurred during the transferring process between the 2-D shape of mask pattern and the resulting wall of the fabricated 3-D structure, we have developed newly useful graphical data on the absorbed X-ray energy, dosage, and shape of a microstructure. As a result, it is being reported as a method for compensation for the deformed shape after the fabrication of a quadruplets-microneedle. We have considered a number of factors affecting the deformation and finally realized that the effect of a dose–depth nonlinear curve is the most possible cause. Without the compensation of the mask design, we could observe the deformed shapes of the sloped sidewall on the exposed structures. Polymethylmethacrylate microneedle structures fabricated by X-ray lithography with an additional plane-pattern to cross-section transfers technique are directly influenced by the absorber on the X-ray mask pattern. The sidewall of the microneedle was improved by changing the mask pattern from a double right-triangular pattern to a double semi-circular pattern, modeled by comparing the results from a mask-pattern and the actual structure.
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Acknowledgments
The authors would like to thank Mr. Hiroyuki Ikeda, a technician in the SR center, Ritsumeikan University, for his technical assistance and Dr. Hiroshi Ueno for the useful data.
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Horade, M., Khumpuang, S., Fujioka, K. et al. Mask design compensation for sloped sidewall structures fabricated by X-ray lithography. Microsyst Technol 13, 215–219 (2007). https://doi.org/10.1007/s00542-006-0219-7
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DOI: https://doi.org/10.1007/s00542-006-0219-7