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Proceedings Paper

3D, high-resolution deep x-ray absorber mask
Author(s): Niculae Dumbravescu; Luminita Grigore
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Paper Abstract

Although, by using gray-tone lithography and common technologies in standard IC fabrication it's easy to obtain an arbitrarily 3-D shaping of positive thick resists, there are some limitations too. E-beam writing implies a maximum of only 200 gray-levels on the project retilce, and the limited focus depth of the projection objective gives a poor lateral resolution. That's why we applied a new approach to enhance the 3-D resolution of gray-tone lithography. By combining gray-tone lithography with binary masking technique, it was possible to obtain a high resolution (vertical and horizontal directions) into thick resist. Considering it as a primary mold, a metallic variable absorber mask for deep X-ray lithography may be processed. Previously, it's necessary to transform the resist surface into a conductive layer as follows: conditioning, nucleation and electroless plating, respectively. After that, a metallic deposit is obtained by electroplating at a desired thickness, resulting in a complementary shape of the mold resist. The original design and fabrication method for the gray-tone test reticle were supported by preliminary experiments showing the main advantage of this new technology: the 3-D structuring of thick resists in a single exposure step and also a very promising aspect ratio obtained of over 9:1.

Paper Details

Date Published: 18 August 2000
PDF: 8 pages
Proc. SPIE 4179, Micromachining Technology for Micro-Optics, (18 August 2000); doi: 10.1117/12.395694
Show Author Affiliations
Niculae Dumbravescu, National Institute for Research and Development in Microtechnologies (Romania)
Luminita Grigore, National Institute for Research and Development in Microtechnologies & Univ. of Surrey (Romania)


Published in SPIE Proceedings Vol. 4179:
Micromachining Technology for Micro-Optics
Sing H. Lee; Eric G. Johnson, Editor(s)

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