Preparation and characterization of molecular photoresists: Crosslinkable positive and water developable negative tones

The development of a water-developable negative photoresist from β-CD using an acid-catalyzed chemical amplification method is investigated here. Tertiary butoxyl protected β-cyclodextrin (t-BOC-CD) is also synthesized and used to prepare a positive photoresist. Glutaraldehyde is added as a crosslinking agent for both positive and negative photoresists. Deprotection of t-BOC-CD is accelerated by a photo-induced acid. In the presence of glutaraldehyde and acid, both the deprotected t-BOC-CD and β-cyclodextrin are crosslinked. The introduction of a t-butoxyl group into the β-CD molecule and the addition of glutaraldehyde into the β-CD molecules are both found to decrease the crystallinity of the molecules, improving the resist film properties. The etching resistance of both positive and negative photoresist films is improved by the crosslinking method.