Full Content is available to subscribers

Subscribe/Learn More  >

Development of LIGA-Like Process With Positive Photoresist and SU-8

[+] Author Affiliations
Yongsu Lee, Jinha Kim, Seungsub Lee

Korea Advanced Institute of Science and Technology, Daejon, Republic of Korea

Seokwoo Lee

Stanford University, Stanford, CA

Paper No. IMECE2010-38379, pp. 155-160; 6 pages
  • ASME 2010 International Mechanical Engineering Congress and Exposition
  • Volume 10: Micro and Nano Systems
  • Vancouver, British Columbia, Canada, November 12–18, 2010
  • Conference Sponsors: ASME
  • ISBN: 978-0-7918-4447-2
  • Copyright © 2010 by ASME


LIGA-Like techniques allows the fabrication of structures with high aspect ratio. SU-8 is a well-known thick photoresist used in this process. However, the remainder of highly cross-linked epoxy after photolithography process is difficult to remove without damage or alteration to electroplated metal due to the high aspect ratio of the structure. Different from SU-8, positive photoresist is easily removed, yet has limitation of fabricating structures with high aspect ratio. In this paper, we present novel LIGA-Like process with positive photoresist to improve above mentioned difficulties. In order to increase a height of positive photoresist, we have introduced SU-8 into the system. SU-8 is used for cast to control the thickness of positive photoresist, and AZ9260 (positive photoresis) is used for electroplating mold. In this suggested process, Donut-shaped SU-8 cast is patterned on the border of substrate to control and increase total height of positive photoresist. AZ9260, a kind of positive photoresist, fills the center of vacant area, and the thickness of the AZ9260 is controlled by height of SU-8 cast during the process of slow spin coating. After spin coating, the system is exposed to natural atmospheric condition for hours to improve surface planarization. The soft baking is carried out in two steps. The purpose of first prebaking is to evaporate large amount of solvent, and second prebaking is to enhance aspect ratios of photoresist. In the process of prebaking, the AZ9260 coated wafer is covered with chalet due to the fast dry process causes wrinkle and bubble on the surface. Through extensive experiments, we have established the condition of spin coating, exposure doses, prebaking and development process in each structure of 150, 200 and 240 μm thickness. Different from the case of SU-8, AZ9260 mold can be effectively removed after electroplating treatment. Finally, we obtain metal structures of 150, 200, 240μm heights corresponding to the mold height (AZ9260). It is shown that SU-8 can be successfully replaced by positive photoresist in LIGA-Like process. Therefore, the suggested fabrication method can be applied to materialize the positive photoresist structures with high aspect ratio in UV lithography process.

Copyright © 2010 by ASME
Topics: Photoresists



Interactive Graphics


Country-Specific Mortality and Growth Failure in Infancy and Yound Children and Association With Material Stature

Use interactive graphics and maps to view and sort country-specific infant and early dhildhood mortality and growth failure data and their association with maternal

Citing articles are presented as examples only. In non-demo SCM6 implementation, integration with CrossRef’s "Cited By" API will populate this tab (http://www.crossref.org/citedby.html).

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In