Dipartimento Interateneo Di Fisica, Politecnico & Università Degli Studi di Bari, Bari, Italy.
Institute for Photonics and Nanotechnologies (IFN), National Research Council, Bari, Italy.
Sci Rep. 2023 Mar 28;13(1):5062. doi: 10.1038/s41598-023-31969-y.
Many devices and objects, from microelectronics to microfluidics, consist of parts made from dissimilar materials, such as different polymers, metals or semiconductors. Techniques for joining such hybrid micro-devices, generally, are based on gluing or thermal processes, which all present some drawbacks. For example, these methods are unable to control the size and shape of the bonded area, and present risks of deterioration and contamination of the substrates. Ultrashort laser bonding is a non-contact and flexible technique to precisely join similar and dissimilar materials, used both for joining polymers, and polymers to metallic substrates, but not yet for joining polymers to silicon. We report on direct transmission femtosecond laser bonding of poly(methyl methacrylate) (PMMA) and silicon. The laser process was performed by focusing ultrashort laser pulses at high repetition rate at the interface between the two materials through the PMMA upper layer. The PMMA-Si bond strength was evaluated as a function of different laser processing parameters. A simple, analytical, model was set up and used to determine the temperature of the PMMA during the bonding process. As a proof of concept, the femtosecond-laser bonding of a simple hybrid PMMA-Si microfluidic device has been successfully demonstrated through dynamic leakage tests.
许多设备和物体，从微电子到微流控，都由不同材料制成的部件组成，如不同的聚合物、金属或半导体。一般来说，连接这种混合微器件的技术基于胶合或热工艺，但这些方法都存在一些缺点。例如，这些方法无法控制键合区域的大小和形状，并且存在衬底恶化和污染的风险。飞秒激光键合是一种非接触式、灵活的技术，可以精确地连接相似和不同的材料，既可以用于连接聚合物，也可以用于连接聚合物和金属基底，但还不能用于连接聚合物和硅。我们报告了通过聚甲基丙烯酸甲酯 (PMMA) 和硅的直接透射飞秒激光键合。激光工艺是通过在上层 PMMA 中聚焦高重复率的超短激光脉冲在两种材料的界面处进行的。评估了不同激光处理参数对 PMMA-Si 键合强度的影响。建立了一个简单的分析模型，用于确定键合过程中 PMMA 的温度。作为概念验证，通过动态泄漏测试成功地演示了简单的混合 PMMA-Si 微流控器件的飞秒激光键合。
