Cross Method Research Of The Impaction On Etch Rate And No-uniformity Of SiO₂ And Photo Resist During Plasma Etching

With the development of IC technology, the integrity of IC chip is increasing and wafer size is larger. The control of plasma etching etch rate and non-uniformity is getting more and more important. The plasma etching is a complex process of ion movement in electronic-magnetic field and process of physical-chemical reaction. It's difficult to set up a simple model to calculate the etch rate and non-uniformity of the whole wafer.According to this special condition, this paper use orthogonal experimental design, arranged the test scheme scientifically, selecting gas flow, etching process pressure, rotation magnetic field intensity and RF power, following the orthogonal experimental design testing their affection on the etching rate and no-uniformity of SiO2 wafer and PR wafer during plasma etching. By analyzing the experiment results, we got the most effective factors of plasma etching. This result provides useful reference for new process development and etching tool maintenance.Orthogonal experimental results show that:Process gas flow is the most effective factors, while RF power has sensitive influence as power increased. When RF power lower than 1000W and CF4/Ar flow rate below 20%, the process mainly is physical etch, if flow rate over 20% the chemical etching increased obviously. When RF power above 1000W, it will dominative the plasma etching by physical bombardment. Magnetic has intense influence on Non-uninformative, the affection of other parameters are no-obviously. All factors impact the plasma etching by changing the plasma density and ion movement, so the Etching rate and No-uniformity has low correlation with wafer type. The selective of PR to SiO2 mainly between 0.5~0.6, all factors show low affection.