Thin Film Fracture and Decohesion in Micro- and Nano-Patterned Devices

提案ID：0408487 PI：Sottos，Nancy Organization：伊利诺伊大学厄巴纳-香槟分校标题：微纳图案化器件中的薄膜断裂和脱粘本研究主要关注通过软光刻方法制造的微纳图案化薄膜器件中的独特断裂和脱粘问题。软光刻包括一组技术，例如微接触印刷（m-CP）和纳米转移印刷（n-TP），其使用柔性弹性体印模在基底表面上形成自组装单层（SAM）的图案。SAM然后可以用作用于选择性蚀刻的抗蚀剂或用于选择性沉积的模板以形成最终的薄膜器件。这些加性图案化方法用于创建复杂的2-D和3-D结构，其特征尺寸范围从数百微米到数十纳米，适用于电子、传感器和MEMS中的广泛应用。提出了一种实验和计算相结合的方法来研究表面化学、界面断裂能、加工引起的残余应力和图案化薄膜中的裂纹之间的关系。本提案中描述的研究将产生几种新的实验和计算工具，图案化的膜难以通过常规的粘附性测试来表征。薄膜的粘合强度将在全范围的混合模式的动态加载条件下，使用激光诱导脉冲加载技术的特点。激光脉冲吸收产生高振幅、短持续时间的应力波脉冲以加载膜和衬底之间的界面。将开发动态边缘脱层试验以获得界面的起始和扩展断裂韧性。有意义的断裂参数的链接实现与适当的分析和数值工具的帮助下，以支持实验。将联合收割机谱方法与内聚体积有限方法相结合的强大数值方案将被开发以精确地提取界面断裂韧度。根据当前研究开发的实验和计算工具将提供对图案化薄膜断裂的定量理解，可以指导新油墨、转移化学品和用于软光刻制造的下一代器件的印模的设计和开发。本计画整合薄膜制程、实验力学及数值断裂分析等研究活动，为伊利诺伊大学的两名研究生的教育和培训提供了良好的环境。此外，这些学生将成为贝克曼高级科学与技术研究所跨学科研究小组的一部分，这将促进与化学，化学工程和材料科学的其他学生和教师进行更广泛的互动。一个额外的REU补充将被要求支持两个本科研究人员在实验和计算方面的项目工作。将努力从任职人数不足的群体中征聘研究生担任这些职位。PI参加了一些推广活动，以增加人才库，招募和留住本科和研究生阶段代表性不足的学生。

Proposal ID: 0408487PI: Sottos, NancyOrganization: University of Illinois at Urbana-ChampaignTitle: Thin film fracture and decohesion in micro- and nano-patterned devicesThis research focuses on the unique fracture and decohesion problems associated with micro-and nano-patterned thin film devices fabricated via soft lithographic methods. Soft lithography encompasses a group of techniques, such as microcontact printing (m-CP) and nanotransfer printing (n-TP) that use a flexible elastomeric stamp to form patterns of self-assembled monolayers (SAMs) on the surfaces of substrates. The SAMs can then serve as resists for selective etching or templates for selective deposition to form the final thin film device. These additive methods of patterning are used to create complex 2-D and 3-D structures with feature sizes ranging from hundreds of microns to tens of nanometers for a broad set of applications in electronics, sensors and MEMS. A collaborative experimental and computational approach is proposed to investigate the relationships between surface chemistry, interfacial fracture energy, processing induced residual stress, and cracking in patterned thin films.Intellectual Merit: The research described in this proposal will result in several new experimental and computational tools to quantify the interfacial fracture energy in ultra-thin, patterned films that are difficult to characterize by conventional adhesion tests. Thin film adhesive strength will be characterized under a full range of mixed-mode dynamic loading conditions using a laser induced pulsed loading technique. Laser pulse absorption generates high amplitude, short duration stress wave pulses to load the interface between a film and a substrate. A dynamic edge delamination test will be developed to obtain the initiation and propagation fracture toughness of the interface. The link to meaningful fracture parameters is achieved with the aid of appropriate analytical and numerical tools to support the experiments. Powerful numerical schemes that combine spectral methods with cohesive volumetric finite methods will be developed to accurately extract interfacial fracture toughness. The experimental and computational tools developed under the current research will provide a quantitative understanding of patterned film fracture that can guide the design and development of new inks, transfer chemistries, and stamps for the next generation of devices fabricated by soft lithography.Broader Impact: This project integrates research activities involving thin film processing, experimental mechanics and numerical fracture analysis, providing an excellent setting for the education and training of two graduate students at the University of Illinois. Moreover, these students will be part of an interdisciplinary research group at the Beckman Institute for Advanced Science and Technology that will facilitate broader interactions with other students and faculty from Chemistry, Chemical Engineering, and Materials Science. An additional REU supplement will be requested to support two undergraduate researchers to work on both experimental and computational aspects of the project. Efforts will be made to recruit graduate students from underrepresented groups for these positions. The PIs participate in a number of outreach activities to increase the pool, recruit and retain underrepresented students at the undergraduate and graduate levels.