Choi Woong-Kirl, Kim Seong-Hyun, Choi Seung-Geon, Lee Eun-Sang
Department of Mechanical Engineering, Inha University, Incheon 402-751, Korea.
Materials (Basel). 2018 Jan 19;11(1):160. doi: 10.3390/ma11010160.
Ultra-precision products which contain a micro-hole array have recently shown remarkable demand growth in many fields, especially in the semiconductor and display industries. Photoresist etching and electrochemical machining are widely known as precision methods for machining micro-holes with no residual stress and lower surface roughness on the fabricated products. The Invar shadow masks used for organic light-emitting diodes (OLEDs) contain numerous micro-holes and are currently machined by a photoresist etching method. However, this method has several problems, such as uncontrollable hole machining accuracy, non-etched areas, and overcutting. To solve these problems, a machining method that combines photoresist etching and electrochemical machining can be applied. In this study, negative photoresist with a quadrilateral hole array pattern was dry coated onto 30-µm-thick Invar thin film, and then exposure and development were carried out. After that, photoresist single-side wet etching and a fusion method of wet etching-electrochemical machining were used to machine micro-holes on the Invar. The hole machining geometry, surface quality, and overcutting characteristics of the methods were studied. Wet etching and electrochemical fusion machining can improve the accuracy and surface quality. The overcutting phenomenon can also be controlled by the fusion machining. Experimental results show that the proposed method is promising for the fabrication of Invar film shadow masks.
最近，包含微孔阵列的超精密产品在许多领域，尤其是半导体和显示行业，需求增长显著。光刻胶蚀刻和电化学加工作为加工微孔的精密方法广为人知，其加工出的产品无残余应力且表面粗糙度较低。用于有机发光二极管（OLED）的因瓦荫罩包含大量微孔，目前采用光刻胶蚀刻法进行加工。然而，这种方法存在一些问题，如孔加工精度不可控、存在未蚀刻区域以及过蚀刻现象。为了解决这些问题，可以应用一种将光刻胶蚀刻和电化学加工相结合的加工方法。在本研究中，将具有四边形孔阵列图案的负性光刻胶干涂覆在30μm厚的因瓦薄膜上，然后进行曝光和显影。之后，采用光刻胶单侧湿法蚀刻以及湿法蚀刻 - 电化学加工的融合方法在因瓦上加工微孔。研究了这些方法的孔加工几何形状、表面质量和过蚀刻特性。湿法蚀刻和电化学融合加工可以提高精度和表面质量。过蚀刻现象也可以通过融合加工来控制。实验结果表明，所提出的方法对于制造因瓦薄膜荫罩具有很大的前景。
