Abstract This paper theoretically and experimentally studies an innovative laser lift-off (LLO) technique that utilizes a line-shaped laser to scan the interfacial polyimide (PI) film through the transparent substrate to peel off the thin-film electronics. A comprehensive illustration of the mechanism of the occurrence of wrinkles in ultrathin PI films is provided, based on which the LLO process for ultrathin flexible electronics is optimized. A mechanical model is established to describe the deformation of the laser-induced blister and validated by experimental results. The results show that the wrinkles are due to the plastic deformation inside the film, which is caused by the instantaneous pressure of gas products generated by laser ablation. By measuring the instantaneous pressure through piezoelectric sensors, the maximum allowable laser fluence without inducing plastic deformation has been found, which decreases linearly with the film thickness. Accordingly, the process window of the traditional single-pass LLO has been obtained, which confirms that the wrinkles in ultrathin PI films (

中文翻译：

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柔性电子无皱超薄聚酰亚胺薄膜激光剥离的理论与实验研究

摘要 本文从理论上和实验上研究了一种创新的激光剥离（LLO）技术，该技术利用线形激光通过透明基板扫描界面聚酰亚胺（PI）薄膜以剥离薄膜电子器件。全面阐述了超薄PI薄膜产生皱纹的机理，并在此基础上优化了超薄柔性电子器件的LLO工艺。建立了描述激光诱导泡罩变形的力学模型，并通过实验结果进行了验证。结果表明，皱纹是由于薄膜内部的塑性变形造成的，这是由激光烧蚀产生的气体产品的瞬时压力引起的。通过压电传感器测量瞬时压力，已发现不引起塑性变形的最大允许激光能量密度，其随薄膜厚度线性减小。因此，获得了传统单程LLO的工艺窗口，这证实了超薄PI薄膜中的皱纹（