LED芯片衬底材料近极限光滑表面高效平坦化原理与方法

At present, with the rapid development in the light emitting diode (LED) manufacturing technology, Higher requirements for the surface smoothness, finish and material removal rate of LED chips substrate, such as the sapphire (Al2O3), silicon carbide (SiC) have been put forward to enhance the LED luminous efficiency and reduce the cost, in which the demand for the surface finish approach to their limit value. This naturally poses a great challenge to the surface planarization for the difficult machining substrate materials. To attain the LED chips substrate with highly effective removal and close-to-smooth-limited surface without damage, this project puts forward a new thought that combine contact catalysis principle and minimum nanoabrasives in the planarization, study the contact catalysis behavior 、material removal mechanism and planarization principal among the polishing pad 、abrasive grains with catalytic activation and wafer surface, and realize the rapid removal and high effective planarization of difficult-to-machine substrate materials. At the same time, through the exploration of the minimum nanoparticles behavior、the rule of material removal mechanism evolution and atom level removal mechanism in the planarization, realized close-to-smooth-limited surface manufacturing, and finally provided an new principle, technique and theoretical support for the production of advanced electronic products, such as future LED chips ,etc.

目前，发光二极管（LED）制造技术快速发展，为了提高LED发光效率，降低成本，对蓝宝石（Al2O3）、碳化硅（SiC）等LED芯片衬底材料表面平整度、光洁度以及材料去除速率等提出了更高的要求，其中对表面光洁度的要求更是接近了物理极限值，对难加工衬底材料表面平坦化提出挑战。为实现LED芯片衬底材料高效去除和近极限光滑无损伤表面的制造，我们提出在平坦化中引入接触催化原理与极小纳米抛光粒子相结合的思路，通过探索平坦化中具有催化作用的抛光垫、抛光粒子与晶片表面材料的接触催化行为、材料去除机制与平坦化原理，以实现难加工材料快速去除和高效平坦化；同时，通过探索平坦化中极小纳米粒子行为、粒子粒度变化过程中材料去除机制的演变规律、平坦化过程中原子级去除机制，以实现近极限光滑表面制造，为未来LED芯片等先进电子产品的纳米制造提供新的原理、技术与理论支持。

针对LED 芯片衬底材料高效去除和近极限光滑无损伤表面制造, 项目组在平坦化中引入催化原理与极小纳米抛光粒子相结合, 以实现难加工材料高效超精平坦化。通过分析LED芯片衬底材料物化特性，研制出新型催化剂和催化固结型抛光垫,均有效提高了蓝宝石晶片平坦化效率。通过研究平坦化中新型催化剂、抛光磨粒与晶片表面材料的作用规律,探索出新型催化剂在蓝宝石平坦化中的作用机制。同时，项目组在平坦化体系中引入紫外光催化作用，开发出适用于CMP的紫外装置，通过改性N型半导体催化颗粒（氧化钛），抑制光生载流子的复合，提高界面电子转移速率常数，提高CMP过程中紫外催化效率，使平坦化效率提高3.88倍。项目组自主研发出极小纳米颗粒, 并运用于衬底平坦化，获得原子级超精表面，通过系统研究颗粒粒径与平坦化性能的关系，揭示了纳米颗粒与材料表面的作用规律。融合催化和极小纳米颗粒在平坦化中的运用，探索出原子级光滑表面高效平坦化方法，研究结果达到了预期目标。