Synthesis and characterization of chiral polyacrylates and their applications as positive tone photoresists

Abstract

To estimate the effects of diastereomeric copolymers as photoresists, diastereomeric copolymers containing chiral and racemic bornyl methacrylates (BMAs) were synthesized. Both alicyclic BMAs were synthesized from (2)-borneol and (6)-borneol, and then copolymerized with t-butyl methacrylate (t-BMA), tetrahydro-pyranyl methacrylate (THPMA), and a-methacryloxy-g-butyrolactone (MABL). The glass transition temperature of the copolymers was found to increase with an increase in the content of alicyclic bornyl groups in the copolymers. To investigate the effect of both the alicyclic butyrolactone and the bornyl groups on photosensitivity, thermal property, and etching resistance, the synthesized alicyclic copolymers were used to prepare photoresists with photoacid generators. The sensitivity and the contrast of the photoresists were calculated. This investigation demonstrated that the existence of alicyclic butyrolactone and bornyl groups increases the etching resistance of photoresists. It was also found that high stereo hindered bornyl structures disturb and restrict the mobility of the polymer chain, leading to an increase in the thermal stability of the polymers. A real pattern recording of photoresists with PR3 composition was performed; an optimal sensitivity of 20 mJ/cm 2 and resolution of 1 lm of positive tone photoresists with 1 lm thickness was achieved.

25th Anniversary Article: Ordered Polymer Structures for the Engineering of Photons and Phonons

“…This latter technique allows for preprogramming of the individual domains by deliberate positioning of the embedded template, even allowing the potential for determining through simulations the optimal surrogate post arrangement to arrive at a specified target structure. 73 While two layer templated BCP from a 2D embedded template has been demonstrated ( Figure 5 a), 74 full 3D graphoepitaxy has only been demonstrated in a limited sense for BCP within ordered and disordered 75 , 76 interstitial pores. For example, lamellar BCP have been previously backfilled into colloidal or inverted colloidal structures.…”

Micro‐/Nanostructured Mechanical Metamaterials

“…These are similar to unstructured, field‐driven methods of BCP alignment, such as magnetic,239 electronic,240 mechanical,241 thermal,242–244 or directional solvent245 evaporation or crystallization246 driven alignment. Epitaxy of 3D self‐assembly is a less studied area, though it has been demonstrated for colloids within conventional lithographic233 or IL247 templates (Figure 20c) and block copolymers within ordered and disordered pores 248–250. Such structures could definitely possess interesting mechanical properties, but have yet to be analyzed with this in mind.…”