Thermal conductivity measurements of thin-film resist

Abstract

In electron-beam and photolithography, local heating can change the resist sensitivity and lead to variations in significant critical dimension. Existing models suffer from the lack of experimental data for the thermal properties of the polymer resist films. We present the measurements of both out-of-plane and in-plane thermal conductivity of thin resist films following different exposure conditions. An optical thermoreflectance technique was used to characterize out-of-plane thermal conductivity; the out-of-plane thermal conductivity of exposed SPR™-700 resist increases as a function of exposure dose. We also designed and fabricated a free-standing micro-electrode structure for measuring the in-plane thermal conductivity and results for poly͑methylmethacrylate͒ films were obtained, indicating that, unlike polyimide films, there is no appreciable anisotropic behavior.

Exploration of thermolithography for micro- and nanomanufacturing

“…Measurements performed at temperatures up to 125°C do not reveal any significant temperature dependence. The present thermal conductivity is much larger than the effective thermal conductivity reported previously 12 for another commercially available photoresist ͑Shipley SPR-700͒ based on a similar novolac resin. We believe that the discrepancy is due to the significant thermal boundary resistance between the metal heater and photoresist layer of the previous study, which was not corrected for.…”

Thermo reflectance bolometry

“…[17][18][19] Here a small energy fraction reflected from the supporting glass substrate back into the metal film was neglected as it constitutes ϳ5% of the total transmitted energy. 7 It is seen in Fig. 3 that the response of the bolometer is flat in the range of low electron energies defined by the thickness of the metal film.…”

“…7 The only application of this property in the gas discharge physics was done for the estimation of electrode temperature evolution during starting up of high-pressure arc lamps. 8 However, as far as we know it has never been used for bolometry.…”

Contact Thermal Lithography

“…[14] In the latter case, however, thermal conductivity was shown to be roughly 2/3 the bulk value. To complicate matters further, thermal conductivity is a function of both temperature and the degree of crosslinking in the polymer.…”