We have measured the absolute fluorine atom concentrations in electron cyc!o!ron resonance (ECR! and reactive ion etching !ME) plasmas by optimizing the actinometry technique. The major difference between this work and conventional actinometry is that the Ar concentration measurements were pelformed by a residual gas analyser (RGA). The emission intensities of F (7037 A) and Ar (7504 A) were simultaneously measured by an optical multichannel analyser (OM) and the Ar concentration by a RGA. The F atom concentration at the wafer stage in the CF4 ECR plasma was measured to be (0.4 to 4)x1Ol2 ~m -~, the microwave power from 500 to 900 W, pressure from 0.5 (3.7 sccm) to 3.5 mTorr (58 sccm), and a fixed RF bias voltage of -50 V. The F atom concentration of the CF, ECR plasma was four times larger in the source region than in the downstream region. The F atom concentration of the CF4 RIE plasma for pressures from 13 to 62 mTorr was measured as (0.8 to 4 . 2 ) ~l O ' ~ ~m -~, for a CF4 flow rate of 20 sccm, and power inputs from 250 to 1500 W. The F atom concentration was larger in the RIE etcher than in the ECR etcher, but the F atom production efficiency was eight times larger in the ECR etcher than in the RE etcher for the same power level. In spite of the possibility of a factor two discrepancy in the measurements from absolute values because of the uncertainty in the absolute values of the cross sections, this technique provides a relatively simple and consistent reproducible measurement of F atom concentration to compare operation of the two types of etchers, which is reproducible to 110%.We further explored the actinometry for vacuum ultraviolet (vuv) emission region by using F (955 A) and Ar (1048 A). A similar trend of F atom concentration was found as for the visible actinometry, but the absolute value of fluorine atom concentration was typically 15% larger for the vuv actinometry.
A symmetric rate model for plasma etching and plasma deposition in fluorocarbon plasmas is proposed. When there is no deposition, the symmetric rate model gives a plasma etch rate. When there is no etching, the model gives a plasma deposition rate. Electron cyclotron resonance and reactive ion etcher etch rates of SiO 2 in CF 4 plasma are found to be consistent with the model. © 1996 American Institute of Physics. ͓S0003-6951͑96͒02212-3͔Plasma etching is an important technology in the fabrication of very large scale integrated circuits.1 With the feature size smaller than 0.5 m, the empirical approach for the optimization of plasma etching is getting more and more difficult, and basic understanding of plasma etching is becoming crucial for process control. In the etching of SiO 2 with fluorocarbon plasmas, both etching and deposition occur simultaneously 2 and both processes need to be understood.Many rate models have been proposed for plasma etching ͑see Refs. 3-8 and references therein͒. Among these models, Zawaideh and Kim 7 proposed a model to include both linear effects of chemical and physical etching, and the nonlinear effect of ''enhanced'' chemical and physical etching. Hoffmann and Heinrich 8 simplified the model proposed by Zawaideh and Kim to describe reactive ion etching ͑RIE͒ of polysilicon with SF 6 plasma. Gottscho, Jurgensen, and Vitkavage 10 proposed an ion-neutral synergy model based on the mass transport model proposed by Mayer and Barker. 3,5 In this letter, a symmetric rate model for plasma etching and deposition is developed.In both plasma etching and deposition, energetic ions, etching species, and deposition species have been shown to be important. [9][10][11][12][13][14] showed that plasma etching and deposition rates of plasma perfluoropolymer thin films have a similar dependence on ion energy. Ding et al. 10 found in an electron cyclotron resonance ͑ECR͒ etcher that the etch rates of SiO 2 with CF 4 /O 2 /Ar plasmas only depend on ion energy flux and F-atom density. They quantified the boundary between the ion energy flux limited regime and the F-atom flux limited regime. Mutsukura et al.11 studied the deposition of hydrogenated hard-carbon films in a CH 4 rf discharge plasma. They found at high pressure that the film deposition rate was predominantly dependent on the ion energy flux. They also found at very low pressure that the film deposition rates were almost the same for different rf power at each pressure condition. Similar trends have also been found by the other groups. 12-14Based on the experimental results and the models mentioned earlier, we assume that the ion enhanced chemical etch rate and the ion enhanced chemical deposition rate are proportional to the ion energy flux multiplied by the surface coverage of the etching or deposition species. This assumption means the etch rate and deposition rate are symmetric. If the products of the reaction are volatile, then the process results in net etching. If the products of the reaction are involatile, then the process results in...
Abstract:The cutting properties of tools can be greatly improved by AlCrSiN coatings. The AlCrSiN coatings with nitrogen content in the range of 28.2-56.3 at. % were prepared by varying the N 2 /Ar flow ratio from 1/4 to 1/1. The influence of N 2 /Ar flow ratio on composition, microstructure, and mechanical properties, as well as the tribological properties, of the coatings was investigated. With increasing N content, the coating microstructure gradually evolved from single fcc-(Cr,Al)N (200) phase to the mixture of fcc-(Cr,Al)N and hcp-(Cr,Al)N phase, which corresponds to an increased crystallinity within the coatings. The coating presents the highest hardness and best wear resistance for an N 2 /Ar flow ratio of 1/1, but the film adhesive strength and inner stress decreased obviously with increasing N 2 /Ar flow ratio, which was attributed to the rapid reduction of particle kinetic energy induced by the obstruction of neutral nitride particles between target and substrates. The highest H 3 /E* 2 value exhibited the lowest wear rate, at 0.81 × 10 −14 m 3 /(N·m), indicating that it had the best resistance to plastic deformation. The main wear mechanisms of the as-deposited coatings were abrasive wear and adhesive wear. The increasing crystallinity of the interior coatings resulted in higher hardness and better tribological behavior with an increase in N 2 /Ar flow ratio.
Multilayered hard coatings with a CrN matrix and an Al2O3, TiO2, or nanolaminate-Al2O3/TiO2 sealing layer were designed by a hybrid deposition process combined with physical vapor deposition (PVD) and atomic layer deposition (ALD). The strategy was to utilize ALD thin films as pinhole-free barriers to seal the intrinsic defects to protect the CrN matrix. The influences of the different sealing layers added in the coatings on the microstructure, surface roughness, and corrosion behaviors were investigated. The results indicated that the sealing layer added by ALD significantly decreased the average grain size and improved the corrosion resistance of the CrN coatings. The insertion of the nanolaminate-Al2O3/TiO2 sealing layers resulted in a further increase in corrosion resistance, which was attributed to the synergistic effect of Al2O3 and TiO2, both acting as excellent passivation barriers to the diffusion of corrosive substances.
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