大尺寸超薄柔性显示衬底Roll-to-Roll高效超精密平坦化机理与关键技术研究

According to the requirements for flexible display substrate on the machining accuracy, the surface quality and the machining efficiency in manufacturing the microelectronics and optoelectronics products, the new high efficiency technology of ultra-precision chemical machanical planarization (CMP) large-size and ultra-thin stainless steel flexible display substrates used Roll-to-Roll method with more than one polishing platen (or roller) under a single installation has been put forward based on these problems of puckering, the low machining efficiency, the high cost and the difficult controlling of the material removal uniformity. This method can match with the subsequent Roll-to-Roll manufacture procedure of electronic device completely. According to the physical properties, chemical properties, and the mechanical properties of stainless steel flexible display substrates, the kinematic properties, the micro-mechanical behavior, the physical and chemical effects, hydrodynamic effects and mechanical friction will be studied. The material removal mechanism, the surface deformation law and surface damage mechanism will be analyzed and the technology of controlling the surface damage and obtaining the high quality surface will be put forward under the field of mechanical and chemical energy in Roll-to-Roll CMP process of the large-size and ultra-thin stainless steel flexible display substrates. The Roll-to-Roll CMP machine, high efficiency Roll-to-Roll CMP slurry, appropriate Roll-to-Roll CMP pad, the equipment of measuring the fluid pressure and temperature and other key technology will be studied and manufactured. The machining process with high precision and damage free will be studied in Roll-to-Roll CMP the large-size and ultra-thin stainless steel flexible display substrates.

本项目根据微电子和光电子产品制造对大尺寸超薄柔性显示衬底的加工精度、加工表面质量和加工效率的要求，针对目前加工中所存在的起皱、加工效率低、加工成本高、材料去除均匀度难以控制等问题，实现与后续电子器件制程无缝对接，提出大尺寸超薄不锈钢柔性显示衬底卷对卷（Roll-to-Roll）连续高效无应力超精密化学机械平坦化新方法；根据超薄不锈钢柔性衬底的物理、化学及机械特性，研究Roll-to-Roll化学机械平坦化中运动学特性、微观力学行为、物理化学效应、流体动压效应及机械摩擦特性，分析不锈钢柔性显示衬底表面材料去除机理、表面变形规律以及表面损伤的产生机理，研究适用于大尺寸超薄柔性显示衬底的Roll-to-Roll连续高效无应力化学机械平坦化加工专用装置、专用高效抛光液、适用抛光垫、界面温度检测装置等，研究大尺寸超薄不锈钢柔性显示衬底Roll-to-Roll超精密高效化学机械平坦化加工工艺。

柔性显示已成为下一代显示技术的研究热点，不锈钢材料将成为柔性大尺寸显示器衬底的主要材料之一。目前对于不锈钢的超精密加工都是单张式的加工方式，加工中存在起皱、加工效率低、加工成本高、材料去除均匀度难以控制等问题，且无法实现与后续电子器件制程无缝对接。本项目根据柔性显示产品制造对衬底的加工质量要求，结合304不锈钢材料的物理机械及化学性能，研制了三种304不锈钢Roll-to-Roll化学机械抛光液、研磨膏与Roll-to-Roll固结磨料抛光辊，研制的抛光液可用于粗抛、半精抛和精抛工序，抛光后的表面粗糙度可达1nm以下。研究了化学机械抛光304不锈钢的化学作用机理，为优化304不锈钢化学机械抛光液、优化抛光工艺提供了理论支持。研究了Roll-to-Roll化学机械抛光机系统的运动学、静力学及动力学特性，为优化抛光机的结构提供参考。研究了化学机械抛光过程变量与超光滑表面质量的关系，探索了大面积不锈钢柔性衬底表面粗糙度及平面度评价方法，提出了基于正交设计思想的检测点优化方案及应用最小二乘原理计算平面度的措施，节省了测量时间。研究了不锈钢亚表面的损伤及表面残余应力分布，得出了固结磨料研磨后表面形成残余压应力，为后续化学机械抛光工艺制订提供参考；设计了Roll-to-Roll连续高效化学机械抛光机，试制了一台Roll-to-Roll连续高效化学机械抛光实验样机，为研究连续高效化学机械抛光机理、工艺提供支持；设计了基于无线信号传输的Roll-to-Roll化学机械抛光界面流体压力及温度在线检测装置，可实现抛光界面的流体压力及温度的时时在线监测；建立了Roll-to-Roll化学机械抛光区域的接触应力模型及摩擦力分布模型，可为研究材料去除机理提供参考；设计了Roll-to-Roll连续高效化学机械抛光界面摩擦特性检测装置，优化了不锈钢化学机械抛光工艺参数，加工出的304不锈钢表面粗糙度达0.7nm，完全满足柔性显示衬底制造技术对衬底表面质量的要求。上述研究结果对于丰富超精密加工理论、提高我国超精密加工水平、促进我国微电子和光电子高新技术产业发展，具有重要的科学意义和应用价值。