Mechanics of crack path selection in microtransfer printing: Challenges and opportunities for process control
Mechanics of crack path selection in microtransfer printing: Challenges and opportunities for process control
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DOI：
10.1016/j.jmps.2020.104066
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发表时间：
2020-10
影响因子：
5.3
通讯作者：
Aoyi Luo;K. Turner
中科院分区：
文献类型：
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作者：
Aoyi Luo;K. Turner
微转移印刷是一种制造技术，其依赖于两个界面之间的受控选择性分层来转移薄固体膜和芯片。这些工艺中的印模通常被设计成利用修改印模界面处的界面应力分布以实现特定粘附响应的策略，然而，印模界面处的修改的应力分布对系统中两个界面之间的裂纹路径选择的影响尚不清楚。利用力学模型研究了微转移印刷过程中印模下的应力分布对两界面间分层路径的影响。通常，改变印模/芯片界面处的应力分布也改变芯片/衬底界面处的应力分布。对于一个足够薄的芯片，没有或小的初始缺陷的接口，常见的方法调整粘附力通过减少应力奇异性附近的邮票的边缘的强度不提供一个强大的路由来控制分层path.A替代邮票的设计策略，由应力分布的奇异性顺序的指导下，提出和分析。在所提出的印模设计中，可以通过印模厚度和剪切位移的应用来控制分层路径。这项工作提供了一个基本的理解，以及指导设计成功的微转移印刷工艺的机制。
Microtransfer printing is a manufacturing technique that relies on controlled selective delamination between two interfaces to transfer thin solid films and chips. Stamps in these processes are often designed to leverage strategies that modify the interfacial stress distribution at the stamp interface to achieve a specific adhesion response, however the effect of a modified stress distribution at the stamp interface on crack path selection between the two interfaces in the system is unclear. This paper investigates how the stress distribution beneath the stamp can affect the delamination path between the two interfaces in a microtransfer printing process using mechanics modeling. In general, altering the stress distribution at the stamp/chip interface also alters the stress distribution at the chip/substrate interface. For a sufficiently thin chip with no or small initial defects at the interfaces, the common approach of tuning adhesion by reducing the strength of stress singularity near the edge of the stamp does not provide a robust route to control the delamination path. An alternative stamp design strategy, guided by the singularity order of the stress distribution, is proposed and analyzed. In the proposed stamp design, the delamination path can be controlled through the stamp thickness and the application of a shear displacement. This work provides a fundamental understanding of the mechanics of the microtransfer printing process as well as guidance for designing successful microtransfer printing processes.