Scanning Deposition Method for Large-Area Diamond Film Synthesis Using Multiple Microwave Plasma Sources.

The demand for synthetic diamonds and research on their use in next-generation semiconductor devices have recently increased. Microwave plasma chemical vapor deposition (MPCVD) is considered one of the most promising techniques for the mass production of large-sized and high-quality single-, micro- and nanocrystalline diamond films. Although the low-pressure resonant cavity MPCVD method can synthesize high-quality diamonds, improvements are needed in terms of the resulting area. In this study, a large-area diamond synthesis method was developed by arranging several point plasma sources capable of processing a small area and scanning a wafer. A unit combination of three plasma sources afforded a diamond film thickness uniformity of ±6.25% at a wafer width of 70 mm with a power of 700 W for each plasma source. Even distribution of the diamond grains in a size range of 0.1-1 µm on the thin-film surface was verified using field-emission scanning electron microscopy. Therefore, the proposed novel diamond synthesis method can be theoretically expanded to achieve large-area films.

Compact water-cooled surface wave plasma source for remote plasma cleaning.

This paper describes the design and operation of a compact surface wave plasma source for remote plasma processing [i.e., plasma enhanced chemical vapor deposition chamber cleaning, dry etching (SiO2, Si3N4, and silicon), photoresist stripping (SU-8), and decapsulation of microchips]. In order to get higher radical generation and increased industrial throughput, the source is designed to generate plasma at a high flowrate. The source is designed to be compact so that it can be more beneficial in the case of positioning multiple sources on a large processing chamber for faster radical cleaning with better uniformity. The source can operate from low to high flowrates (i.e., 100 SCCM H2 or 10 slm NF3) and provide high decomposition rates for NF3. The etching rate for SiO2 (higher than 450 nm/min) is achieved with 2.5 kW microwave power and 3-5 slm. The key advantages of the source are compactness, higher microwave coupling due to indirect water-cooling, and thereby high operating flow and decomposition rates.

Honeycomblike large area LaB6 plasma source for Multi-Purpose Plasma facility.

A Multi-Purpose Plasma (MP(2)) facility has been renovated from Hanbit mirror device [Kwon et al., Nucl. Fusion 43, 686 (2003)] by adopting the same philosophy of diversified plasma simulator (DiPS) [Chung et al., Contrib. Plasma Phys. 46, 354 (2006)] by installing two plasma sources: LaB(6) (dc) and helicon (rf) plasma sources; and making three distinct simulators: divertor plasma simulator, space propulsion simulator, and astrophysics simulator. During the first renovation stage, a honeycomblike large area LaB(6) (HLA-LaB(6)) cathode was developed for the divertor plasma simulator to improve the resistance against the thermal shock fragility for large and high density plasma generation. A HLA-LaB(6) cathode is composed of the one inner cathode with 4 in. diameter and the six outer cathodes with 2 in. diameter along with separate graphite heaters. The first plasma is generated with Ar gas and its properties are measured by the electric probes with various discharge currents and magnetic field configurations. Plasma density at the middle of central cell reaches up to 2.6 x 10(12) cm(-3), while the electron temperature remains around 3-3.5 eV at the low discharge current of less than 45 A, and the magnetic field intensity of 870 G. Unique features of electric property of heaters, plasma density profiles, is explained comparing with those of single LaB(6) cathode with 4 in. diameter in DiPS.