Yoo Hyeonggeun, Shin Hyunkwon, Sim Boyeon, Kim Sangtae, Lee Myeongkyu
Department of Materials Science and Engineering, Yonsei University, Seoul 120-749, Korea.
Nanotechnology. 2009 Jun 17;20(24):245301. doi: 10.1088/0957-4484/20/24/245301. Epub 2009 May 26.
Thin film patterning by the conventional lithographic technique requires a number of steps including the deposition, development, and removal of the photoresist layer. Here we demonstrate that metal thin films evaporated on glass can be directly patterned by a spatially modulated pulsed Nd-YAG laser beam (wavelength = 1064 nm, pulse width = 6 ns) incident from the backside of the substrate. This method utilizes a pulsed laser-induced thermo-elastic force exerted on the film which plays a role in detaching it from the substrate. High-fidelity patterns at the micrometer scale have been fabricated over a few square centimeters by a single pulse with pulse energy of 850 mJ. This is attributed to the fact that deposited metal films are polycrystalline with nano-sized grains, and thus localized etching of the material is possible with shearing along the weakly bonded grain boundary regions. We have also developed a nano-block model to simulate the laser-direct patterning of nanocrystalline thin films. Experimental results could be well described with this simulation model. The patterning process presented here provides a simple photoresist-free route to fabricate metal thin film patterns on transparent substrates.
通过传统光刻技术进行薄膜图案化需要多个步骤，包括光刻胶层的沉积、显影和去除。在此，我们证明了在玻璃上蒸发的金属薄膜可以通过从基板背面入射的空间调制脉冲Nd-YAG激光束（波长 = 1064 nm，脉冲宽度 = 6 ns）直接进行图案化。该方法利用了施加在薄膜上的脉冲激光诱导热弹力，其作用是使薄膜与基板分离。通过单个脉冲，以850 mJ的脉冲能量在几平方厘米的面积上制备了微米级的高保真图案。这归因于沉积的金属薄膜是具有纳米尺寸晶粒的多晶，因此可以沿着弱结合的晶界区域进行剪切，从而实现材料的局部蚀刻。我们还开发了一个纳米块模型来模拟纳米晶薄膜的激光直接图案化。实验结果可以用这个模拟模型很好地描述。这里介绍的图案化过程提供了一种简单的无光刻胶方法，用于在透明基板上制造金属薄膜图案。
