6533b7cffe1ef96bd12599c6

RESEARCH PRODUCT

Fast and blister-free irradiation conditions for cross-linking of PMMA induced by 2MeV protons

Kanda SingkaratS. SingkaratHarry J. WhitlowNirut PussadeeNitipon PuttaraksaSomrit UnaiMichael W. Rhodes

subject

Ability to workMaterials scienceta114BlistersPhotoresistCondensed Matter PhysicsAtomic and Molecular Physics and OpticsSoft lithographySurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsIonResistmedicineIrradiationElectrical and Electronic Engineeringmedicine.symptomComposite materialThin film

description

For soft lithography, the conventional negative tone resists, such as SU-8, that are used to create the mold have a number of drawbacks. PMMA, which is normally used as a positive tone resist, can be used as a negative resist by using high-fluence irradiation conditions. In this report, we outline optimization of the irradiation conditions for PMMA thin films using 2MeV H^+ ions to exploit their ability to work as a negative tone resist at ion fluences above 1.0x10^1^5ionscm^-^2. The main aim was to induce cross-linking while maintaining the exposed regions free of blisters and maintaining short irradiation times. We found that by using a two-step process with a low-flux irradiation, followed by a high-flux irradiation, the exposure time could be shortened by ~50%. We also found that ion fluences greater than 5.0x10^1^5ionscm^-^2 minimized the distortion in stitched regions.

yearjournalcountryeditionlanguage
2013-02-01Microelectronic Engineering
https://doi.org/10.1016/j.mee.2012.05.010