Macromolecular Science and Engineering, ‡Department of Materials Science and Engineering, and ⊥Chemical Engineering, University of Michigan , Ann Arbor, Michigan 48109, United States.
ACS Appl Mater Interfaces. 2012 Jul 25;4(7):3465-70. doi: 10.1021/am3005303. Epub 2012 Jul 3.
As the desired feature size of mold-assisted lithography decreases rapidly efficient demolding process becomes more challenging due to strong adhesion between polymeric resists and fine-featured molds. We synthesized new macromolecular additives and investigated the effects of surface energy and contraction of resist materials on demolding propensity by monitoring the adhesion force between the resist and the applied mold. The resist's surface energy was controlled, as inferred from water contact angle measurements, by chemically modifying its hydroxyl functionality. The resist's degree of volume shrinkage during the photocuring procedure was also controlled by mixing in a newly developed chemical that has a multiple radical chain transfer capability. The adhesion force was proportionally reduced as the surface energy of the resist materials decreased and as the volume shrinkage was reduced. When the volume shrinkage control was applied in conjunction with the low surface energy resist material (LS-30UV), we obtained an optimized condition requiring a minimum force for releasing the mold from the cured resist layer.
随着模具辅助光刻所需特征尺寸的迅速减小，由于聚合物抗蚀剂与精细模具之间的强附着力，有效的脱模过程变得更加具有挑战性。我们合成了新的高分子添加剂，并通过监测抗蚀剂与施加的模具之间的粘附力，研究了表面能和抗蚀剂材料收缩对脱模倾向的影响。通过化学修饰其羟基官能团，从水接触角测量推断出控制抗蚀剂的表面能。通过混合新开发的具有多重自由基链转移能力的化学物质，还控制了抗蚀剂在光固化过程中的体积收缩程度。随着抗蚀剂材料表面能的降低和体积收缩的减少，粘附力成比例降低。当体积收缩控制与低表面能抗蚀剂材料（LS-30UV）一起使用时，我们获得了优化的条件，需要最小的力将模具从固化的抗蚀剂层中释放出来。
