Variation of thermal and mechanical properties of KMPR due to processing parameters

Abstract

We present a study of the thermal and mechanical properties of the negative photoresist KMPR and the influence of processing conditions on those properties. The process parameters chosen all relate to the cross-linking level of the photoresist: the UV exposure dose, the baking temperature and the bake length. The stability of KMPR at high temperatures was also examined. The glass transition temperature was measured using dynamic mechanical analysis, with a maximum measured value of 128 • C achieved in our tests. Relating the glass transition temperature to the cross-linking level of the material, exposure doses higher than 2 J cm −2 were shown to have a negligible effect on the cross-linking (for 80 μm thick films). Using thermogravitmetric analysis, KMPR has been shown to lose significant mass when heated above 200 • C. Young's modulus of KMPR was measured to be between 2.0 GPa for samples hard-baked at 100 • C and 2.7 GPa for samples baked at 150 and 200 • C. Creep behavior for KMPR held under strain was studied for samples prepared under a range of processing temperatures. Finally the thermally-induced cross-linking of unexposed KMPR was studied, with samples post-exposure baked at 150 • C, or 120 • C for at least an hour, cross-linking sufficiently to prevent development.

Scalable fabrication of microneedle arrays via spatially controlled UV exposure

“…Microneedles fabricated in this manner could potentially be used for two purposes: as solid microneedles and as a mold master for dissolving microneedles. KMPR is a photoresist from the SU-8-negative epoxy series (MicroChem Corp.), which exhibit biocompatibility 30 , long-term stability in vivo 31 , sufficient mechanical strength 32 , and stability at body temperature to serve as solid microneedles. Because solid KMPR microneedles are sufficiently strong and sharp to penetrate rat skin, KMPR microneedles could penetrate the skin layers and leave residual holes in the skin (Supplementary Figure S6).…”

Towards environmentally friendly processing of ionic liquid-based photoresists with a boosted lithography performance

“…Thus, the thermal stability of the polymer itself has to be considered. 39 Four copolymers with different IL contents were obtained by free radical polymerization, where the addition of ILs was 0, 50%, 65% and 85%, respectively. To investigate the effect of IL content on the thermal properties of copolymers, TGA and DSC were conducted on the copolymers, and the results are shown in Fig.…”

Configurations of triangular prism and slit electrode pairs to enhance the performance of electro-conjugate fluid micropumps

“…As for TPSEs, they are achieved by a proposed UV-LIGA technique mainly combining micromolding with negative photoresist KMPR 1035 (MicroChem Corp.) and nickel electroforming through the micromolds [25]. Thick photoresist KMPR was developed to have superior properties in easy removal, stronger adhesion to the substrate, and high etching resistance [29], so that it has been utilized as the micromolds for the electroforming [30,31]. First, titanium and gold were successively deposited on the glass wafer as the dual metallic seed layer via thermal evaporation, followed by patterning via the standard lithography.…”