Fabrication of support structures to prevent SU-8 stiction in high aspect ratio structures

Abstract

We have previously demonstrated that it is possible to fabricate densely-packed high aspect ratio structures in SU-8 by means of a top-plate support member which stiffens the overall structure and prevents pattern collapse. In this work we have computed the tensile stresses induced in the top-plate structures due to the capillary forces that arise between the columns due to the surface tension of the drying liquid. We have further studied the dynamic behavior of the structure after an instantaneous force. Based on these results, we have shown that the predicted optimal thickness of the top-plate structure is sufficient to maintain structural integrity.

Sidewall slopes and roughness of SU-8 HARMST

“…In this work (Vora et al 2005c(Vora et al , 2007c we calibrated the dissolution rate, R(E), of SU-8 resist as a function of X-ray exposure dose or the cross-link density. Since SU-8 is a chemically amplified negative resist, it exhibits a ''notch'' in the dissolution behavior like all other resists within this category and hence, the dissolution rate can be predicted by the enhanced notch model (Robertson et al 2001).…”

Design and fabrication of an ac-electro-osmosis micropump with 3D high-aspect-ratio electrodes using only SU-8

“…In order to work out this problem, a dry release process can be used [28][29][30]. However, it requires a special setup; therefore a wet release similar to [31] was applied.…”

Two‐ and Three‐Dimensional Micro‐ and Sub‐Micrometer Periodic Structures Using Two‐Beam Laser Interference Lithography

“…In this case, because the periodic structured is cross-linked at the intercepting nodes due to the double exposure process, independently of spatial period, layer thickness or wall width, the structure is stable enough to resist the attractive capillary forces during the rinse and drying steps. [22] Moreover, no line defects appear on the structure since a two-beam configuration is used.…”