Research on the Mechanism of Multilayer Reactive Ion Etching

Dry etching has now become one of the key processes of high ratio of depth to width microstructure and fine patterning. This paper presents a new dry etching technology - multilayer reactive ion etching technology (MRIE). By taking full advantage of the spatial layout of the chamber, arranging multi-layer electrodes and transporting the discharged gas by a layered air supply device, the function of simultaneous etching in every reaction chamber (layer) is realized. This method can significantly enhance the productivity. Taking the photoresist etching by MRIE as an example, the law and mechanism influencing the etching rate and uniformity were analyzed for different conditions. The result shows that when plate distance is 50/55/60 mm (from bottom to top), and vacuum degree, ratio of O₂ to Ar, RF source power, and continuous etching time are respectively 40 Pa, 1/2, 600 W, and 20 min, the optimal process is achieved. The average etching rate and uniformity are 143.93 Å/min and 9.8%, respectively.