Wan Lei, Ruiz Ricardo
Western Digital Company, WDC Research , 5601 Great Oaks Parkway , San Jose , California 95119 , United States.
ACS Appl Mater Interfaces. 2019 Jun 5;11(22):20333-20340. doi: 10.1021/acsami.9b02925. Epub 2019 May 24.
Directed self-assembly (DSA) of block copolymers (BCPs) has long been viewed as a powerful alternative to extend the resolution of optical lithography. For full-area patterning applications, despite significant progress, the two most prominent DSA methods (chemoepitaxy and graphoepitaxy) are facing a scalability challenge: the critical dimension (CD) of the guiding patterns will need to be continuously scaled down to closely match the dimension of the BCP microdomain, a task that not only contravenes some of the resolution gains achieved by density multiplication but that will also become particularly difficult below 10 nm. To avoid this conundrum, we propose here a synergistic integration of graphoepitaxy and chemoepitaxy through self-registered self-assembly (SRSA) to enable the simultaneous realization of feature density multiplication and CD shrinkage resolution gains. We report nearly perfect DSA on prepatterns with high density multiplication factors and CD of several multiples of the BCP microdomain size. A prepattern consisting of alternating stripes of a relatively thicker neutral mat and a thinner neutral brush with preferential wetting sidewalls serves as a topographic pattern to guide an ultrathin BCP blend film inside the trenches. As the oriented BCP pattern assembles, the blend film deploys a layer of chemical markers on the bottom surface through SRSA generating 1:1 chemical contrast patterns inside the trenches. After thorough removal of the blend film, the newly formed self-registered chemical patterns interpolated by the remaining neutral mat strips serve as the guiding patterns for a second chemoepitaxial DSA step to achieve full-area, defect-free DSA of thick BCP films.
嵌段共聚物（BCP）的定向自组装（DSA）长期以来一直被视为提高光学光刻分辨率的有力替代方法。对于全区域图案化应用，尽管取得了重大进展，但两种最突出的DSA方法（化学外延和图形外延）正面临可扩展性挑战：引导图案的关键尺寸（CD）需要不断缩小，以紧密匹配BCP微区的尺寸，这一任务不仅与通过密度倍增实现的一些分辨率提高相矛盾，而且在低于10纳米时也将变得特别困难。为了避免这一难题，我们在此提出通过自对准自组装（SRSA）将图形外延和化学外延进行协同整合，以同时实现特征密度倍增和CD收缩分辨率提高。我们报告了在具有高密度倍增因子和数倍于BCP微区尺寸的CD的预图案上实现了近乎完美的DSA。由相对较厚的中性垫和较薄的中性刷交替条纹组成的预图案，其侧壁具有优先润湿性，作为一种地形图案，用于引导沟槽内的超薄BCP共混膜。随着定向BCP图案的组装，共混膜通过SRSA在底表面部署一层化学标记，在沟槽内产生1:1的化学对比度图案。在彻底去除共混膜后，由剩余的中性垫条插值形成的新形成的自对准化学图案用作第二步化学外延DSA步骤的引导图案，以实现厚BCP膜的全区域、无缺陷DSA。
