Abstract The reported laser welding of dissimilar materials (metal and plastic) mostly focuses on the optimization of parameters and process, the process is complex and the cost is high. Liquid crystal polymer (LCP) has attracted much attention due to its excellent electrical properties. With the rapid development of information technology, 5G high-frequency communication is gradually emerging. At the same time, there are many problems to be solved, such as the serious skin effect caused by the large copper foil surface roughness and large energy consumption. Therefore, it is urgent to solve this problem for the development of communication technology. Nowadays, the manufacturing process of a two-layer flexible copper clad laminate is not only complex, but also high production cost. In order to try a new manufacturing method and balance the copper foil surface roughness and the bonding strength between the copper foil and LCP, this study proposes a laser integrated manufacturing method for two-layer flexible copper clad laminates, including LCP laser etching, copper foil laser etching and laser welding. We fabricated regular microstructures on the copper foil surface by laser etching, used ultraviolet laser to irradiate the LCP surface, the copper foil and LCP were welded together by laser conduction welding. The surface roughness of the sample was measured by atomic force microscope, the surface morphology was observed by optical microscope, and the bonding strength and peel strength between the etched copper foil and LCP were tested by micro-tensile test. The welding sample bonding strength obtained by this way can reach the ultimate tensile strength of the copper foil, and the peel strength can reach 682.78 N/m, which is close to the reported peel strength obtained by other methods. High-resolution field emission scanning electron microscope and X-ray photoelectron spectrometer were used to reveal the bonding mechanism of the samples. The integrated method is easier to realize automation for the actual production process. Therefore, we have verified that the two-layer flexible copper clad laminate with high bonding strength and peel strength can be prepared by laser processing.

中文翻译：

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铜箔与液晶聚合物的激光蚀刻与焊接直接粘合

摘要 已报道的异种材料（金属和塑料）激光焊接多侧重于参数和工艺的优化，工艺复杂，成本高。液晶聚合物（LCP）因其优异的电性能而备受关注。随着信息技术的飞速发展，5G高频通信逐渐兴起。同时，还有很多问题需要解决，比如铜箔表面粗糙度大、能耗大导致的趋肤效应严重。因此，通信技术的发展迫切需要解决这个问题。如今，两层柔性覆铜板的制造工艺不仅复杂，而且生产成本高。为了尝试一种新的制造方法，平衡铜箔表面粗糙度和铜箔与LCP的结合强度，本研究提出了一种两层柔性覆铜板的激光集成制造方法，包括LCP激光蚀刻、铜箔激光蚀刻和激光焊接。我们通过激光蚀刻在铜箔表面制作规则的微结构，用紫外激光照射LCP表面，通过激光传导焊接将铜箔和LCP焊接在一起。采用原子力显微镜测量样品表面粗糙度，光学显微镜观察表面形貌，微拉伸试验测试蚀刻后的铜箔与LCP的结合强度和剥离强度。通过这种方式获得的焊接试样结合强度可以达到铜箔的极限抗拉强度，剥离强度可以达到682.78 N/m，与其他方法获得的报道剥离强度接近。高分辨率场发射扫描电子显微镜和X射线光电子能谱仪被用来揭示样品的结合机制。集成方式更容易实现实际生产过程的自动化。因此，我们验证了通过激光加工可以制备出具有高结合强度和剥离强度的两层柔性覆铜板。高分辨率场发射扫描电子显微镜和X射线光电子能谱仪被用来揭示样品的结合机制。集成方式更容易实现实际生产过程的自动化。因此，我们验证了通过激光加工可以制备出具有高结合强度和剥离强度的两层柔性覆铜板。高分辨率场发射扫描电子显微镜和X射线光电子能谱仪被用来揭示样品的结合机制。集成方式更容易实现实际生产过程的自动化。因此，我们验证了通过激光加工可以制备出具有高结合强度和剥离强度的两层柔性覆铜板。