An Electrodeless High Density Plasma Source for Large Area Thin Film Processing

摘要

High density plasma sources, such as inductively coupled plasma (ICP), helicon, electron cyclotron resonance (ECR), and microwave, have been successfully used to increase etch and deposition rates for a variety of processes in the semiconductor manufacturing market. However, scaling these high density sources to large areas has proven difficult—particularly where there is a need for very uniform processing. Plasma sources in use for large-area coating, cleaning or etching continue to be the same DC or low-frequency magnetron or capacitively-coupled systems which have been used for the past two decades. In this work, we present an electrodeless high density plasma source which is suitable for large area processing. The source uses an induction-coupled power delivery method to generate plasma within a long rectangular cavity. It is theoretically scalable to nearly any industrially relevant size. Results on a 13.56 MHz, 1.2 Meter long prototype are presented for Argon and Oxygen chemistries. 950 mm long processing regions with less than 4% non-uniformity were obtained for both gases. In 1 mTorr of pure Argon, the average charge density in the uniform region was 5 x 10~(11) cm~(-3); for pure Oxygen at 1 mTorr, an average charge density of 1.5 x 10~(10) cm~(-3) was obtained while maintaining the same uniform region. This source will increase the processing rate for a variety of industrial applications, including LCD manufacturing, architectural glass cleaning and coating, cleaning and deposition on large-area polymer films and large-scale solar cell production.