论文标题
选择性金属薄膜从易感聚合物底物使用脉冲飞秒激光从易感聚合物底物消融的方法论
Methodology of selective metallic thin film ablation from susceptible polymer substrate using pulsed femtosecond laser
论文作者
论文摘要
电子设备是在允许新应用领域的柔性基材上逐步制造的。使用超短脉冲激光辐照消融提供了无掩模且非常灵活的结构过程。通常，将功能性薄膜涂层的某些区域局部拆除以产生所需的设备结构。微激光模式质量不仅受梁特性（梁曲线，通量）的影响，而且还受脉冲重叠，扫描重复以及许多其他因素（例如底物和涂料材料）的影响。这使得过程参数优化成为具有挑战性的任务。在本文中，我们提出了一种系统的方法，可以有效地找到对激光诱导的薄膜在易感聚合物底物上消融的合适参数。例如，我们在通过PI-2611前体的自旋涂层（@ 2000 $ rpm $> ca. 8 $μm$，HD Microsystems）制造的聚酰亚胺膜上使用厚度为100 $ nm $的溅射NICR涂层。使用具有1030 $ nm $的红外波长和212 $ fs $的FS-LASER进行辐照。每脉冲的能量在0,29 $μj$至4,83 $μj$的范围内，得出的通量值在70 $ MJ/cm^2 $和1,11 $ J/cm^2 $之间。发现100 $ nm $ nicr层的消融阈值通量为$ ϕ_ {th} $（$ n_p $：1）= 0,50 $ j/cm^2 $，并且评估孵化因子为$ξ$ = 0,53。必须在散装材料表面的材料消融与薄膜的选择性去除之间进行明确的区别。在第二种情况下，例如剥落在实践中发生并影响消融特征。然后，我们研究了薄膜去除的不同品种，包括点，线和面积。该方法是使用实际示例提出的，但可以应用于多种薄膜系统的选择性消融。
Electronic devices are progressively fabricated on flexible substrates allowing new fields of applications. A maskless and very flexible structuring process is offered by ablation using ultra-short pulse laser irradiation. Usually, certain areas of a functional thin film coating are locally removed to yield the needed device structures. Micro laser patterning quality is not only influenced by the beam properties (beam profile, fluence) but also by pulse overlap, scan repetitions and many other factors such as substrate and coating material. This makes process parameter optimization a challenging task. In this paper, we present a systematic approach to efficiently find suitable parameters for laser-induced ablation of thin films on susceptible polymer substrates. As an example, we use a sputtered NiCr coating with a thickness of 100 $nm$ on a polyimide film made by spin coating of PI-2611 precursor (@ 2000 $rpm$ > ca. 8 $μm$, HD microsystems). Irradiation is conducted using a fs-laser with infrared wavelength of 1030 $nm$ and a pulse length of 212 $fs$. The energy per pulse is varied in the range of 0,29 $μJ$ to 4,83 $μJ$, yielding fluence values between 70 $mJ/cm^2$ and 1,11 $J/cm^2$. Ablation threshold fluence for a 100 $nm$ layer of NiCr was found to be $ϕ_{th}$ ($N_P$:1)=0,50 $J/cm^2$ and the incubation factor was evaluated to be $ξ$=0,53. A clear distinction must be made between the material ablation at the surface of a bulk material and the selective removal of a thin film. In the second case effects such as flaking occur in practice and influence the ablation characteristic. We then investigate different varieties of thin film removal including dot-, line- and areal-ablation. The methodology is presented using a practical example, but can be applied to selective ablation of a wide range of thin film systems.
