Photo-resist Removal using Highly Concentrated Ozone Gas-Removal Characteristics of Various Resists-

Abstract

New processing technologies are demanded which produce hyperfine structures for electronic devices and which do not exacerbate environmental problems. We specifically examined photoresist removal technology for this study. Ozone gas of nearly 100% concentration was applied to various photoresists and ion-implanted-photoresists. Results showed that reactivity with ozone gas differs between a novolac resist, which has a benzene ring structure on a main chain, a KrF resist with this structure on a side chain, and an ArF resist which has no such structure. The activation energy of the KrF resist indicates a value close to that of the novolac resist; the value for the ArF resist was larger than these. Irrespective of the ionic species, the ion-implanted-photoresist of amount 1e16 cm -2 of the dose can be removed with 0.7 µm/min or less in the ashing of 400°C in processing temperature. Additionally, results showed that the removal speed slows in order of B, As, and P.

Effect of Temperature on Degradation of Polymers for Photoresist Using Ozone Microbubbles

“…We obtained the activation energy of about 23 kJ/mol in the removal of novolak resin with ozone microbubbles. It is reported that the activated energy for photoresist removal with ashing using oxygen plasma is 50 kJ/mol, with ashing using dry ozone is 41.5 kJ/mol, and with atomic hydrogen is 19 kJ/mol, with wet ozone is 28 kJ/mol [17][18][19][20]. In accord with these values of the activated energy, Ozone microbubbles is regarded as efficient procedure of photoresist removal.…”

Degradation of Poly(acrylic acid) in Aqueous Solution by Using O₃ Microbubble

“…Poly(methyl methacrylate), which has no C=C bond in the structure, could not be removed from Si wafer by O 3 microbubble. Reactive oxygen species are generally short lifetime, and no significant effect of microbubble on the film removal process confirmed in the previous study [16][17][18][19][20][21]. As further consideration, the degradation of polyethylene glycol (PEG) in aqueous solution by using O 3 microbubble was evaluated, and the effect of microbubbles was confirmed by decrease of the molecular weight and amount of total organic carbon (TOC) in PEG aqueous solution [22].…”

Evaluation of Decomposition Property of Photoresist by Oxygen Radicals Using Helium-Oxygen Mixtures

“…The peak at the temperature of 100-150 °C should represent the shrinkage by volatilization of the solvent. When the photoresist with surfacehardened layer is heated, the layer explodes by increasing the internal pressure induced by escaped gas from the lower layer [19]. This phenomenon is named as "popping", which is famous problem in the removal of ion-implanted photoresist.…”