Cationic electron‐beam curing of a high‐functionality epoxy: effect of post‐curing on glass transition and conversion

Abstract

This paper reports on the cationic electron‐beam curing of a high‐functionality SU8 epoxy resin, which is extensively used as a UV‐curing negative photoresist for micro‐electronics machine systems (MEMS) applications. Results show that elevated post‐curing treatment significantly increased both the conversion and the glass transition. The degree of conversion and the glass transition temperature were measured by using Fourier‐transform infrared (FTIR) spectroscopy and modulated differential scanning calorimetry (MDSC®), respectively. The glass transition temperature (Tg), which has been observed to be dependent on the degree of conversion, reaches a maximum of 162 °C at 50 Mrad and post‐curing at 90 °C. The degradation pattern of the cured resin does not show much variation for exposure at 5 Mrad, but does show significant variation for 50 Mrad exposure at various post‐curing temperatures. A degree of conversion of more than 0.8 was achieved at a dosage of 30 Mrad with post curing at 80 °C, for the epoxy resin with an average functionality of 8 a feature simply not achievable when using UV‐curing. Copyright © 2004 Society of Chemical Industry

Comparison of Conventional and Variable Frequency Microwave Curing of SU8 Photoresist: Effects on the Dielectric, Thermal, and Morphological Properties

“…Feng and Farris [28] found that the Tg is approximately identical to the baking temperature when the processing temperature is less than 220°C and increasing in deviation at higher temperature ranges to a maximum Tg of 238°C at a baking temperature of 300°C, which corroborates with the finding of LaBianca [29]. The Tg of post cured SU8 films has been reported to be always higher than the PEB curing temperature of about 40-70°C [30].…”

“…It can be observed that the Tg is always higher than the PEB temperatures by about 80°C for the HP and HY processed samples and approximately 100°C for the VFM samples. Similar findings have been made by Rath et al [30] who reported Tg of about 40-70°C above the PEB temperature. The Tg values predicted by the Di Benedetto equation seem to be reasonable, although maybe higher than those found in literature.…”

“…(2) [32]. (2) where  is the degree of polymer conversion or degree of cure, Tgo and Tg  are the Tg values at zero and 100% conversion respectively and λ is an adjustable structure dependent parameter which was found to be ~0.88 by Rath et al [2004] for SU8. Using this modified Di Benedetto equation and the results of the degree of cure obtained from the DSC studies, the glass transition temperature for the cured SU8 films were calculated and shown in Fig.…”

Three-Dimensionally-Patterned Submicrometer-Scale Hydrogel/Air Networks That Offer a New Platform for Biomedical Applications

“…This approach is superior to radical polymerization, in which the fast diffusion of radicals and the accompanied refractive index change during polymerization result in less control over microstructure formation. 32,33 Poly(HEMA) is a widely used hydrogel that swells in aqueous solution and has been used in many biomedical applications, such as tissue implant, drug delivery, and contact-lens applications. 34 In this negativetone resist system, the structure can be written by lightinduced cross-linking of the hydroxyl groups of poly(HEMA) via a cross-linker (TMMGU, tetramethoxymethyl glycoluril) which in turn is activated by a photoacid generator.…”

UV curing of a liquid based bismaleimide-containing polymer system

“…The use of radiation curing has been shown to give faster cure rates. This includes the use of microwave curing [19][20][21], UV [22][23] and ebeam [24][25][26] for curing of thin film thermosetting polymers have been shown to give practical and effective advantages [19][20][21]. N-acryloylmorpholine shows a capability to dissolve traditional BMI with high concentration.…”