Plasma etching characterization

Figure 3-8 Raman microprobe spectrum of fluorinated hydrocarbon contaminant on silicon wafer that had been polished and plasma-etched (lower) and Raman spectrum of polytetrafluoro-ethylene (upper). Laser, 135 mW at 514.5 nm. Slits, 300 jon. Time, 0.5 s per data point. (Reproduced with permission from Adar, F., in Microelectronics Processing Inorganic Materials Characterization (L. A. Casper, ed.), ACS Symposium Series Vol. 295, pp. 230-239. American Chemical Society, Washington, D.C., 1986. Copyright 1986 American Chemical Society.)...

Figure 8 shows a plot of thickness of PBS removed versus time in both the CF4/O2 and CF4/He/02 plasmas for samples priorly exposed to an oxygen plasma (lOOW, 0.5 Torr, 3 minutes 16X). The etching curves in the fluorocarbon plasma are characterized by two distinct regions. Initially, the etch rate of PBS is quite high being comparable to that of samples not subjected to pretreatment in O2 plasma (cf. Figure 1). The etch rate then quickly diminishes to a low constant value of 12 2A/min (for CF4/He/02 and 29 5A/min in CF4/O2. When the linear removal rate, obtained from a least-squares plot of the thickness removed versus plasma exposure time, is plotted as an Arrhenius expression at different temperatures (Figure 9), an activation energy of zero is obtained.

The effect of pH on patterned TEOS oxide wafers was also investigated using the MIT CMP Characterization Mask Set pitch mask [1]. The pitch mask is a 6 x 6 array of various equal width lines and spaces. The lines and spaces have widths ranging from 2 pm to 1000 pm. The 12 mm pitch pattern was first created in photoresist across the entire wafer. The expiosed oxide was plasma etched to a depth of about 7000 A below the surface. This created an array of 36 sub-arrays with equal width lines and spaces so that half the area was lines and the other half spaces. The wafers were pwlished with silica slurry at 3 different pH values. The oxide thickness at the plateau area (starting surface of the oxide) for 10 sub-patterns of line widths 40,60,80,100,125, 150, 180, 200,250, and 500 pm were measured before and after CMP. The measurements were made in each sub-array in increasing order of line/space width. Five dies were measured along the diameter of the wafer. 

Yuan LY, Chen CS, Shyu SS, Lai JY, Plasma surface treatments on carbon fibres. 1. Morphology and surface analysis of plasma etched fibres. Composites Sci Technol, 45(1), 1-7, 1992. Commercon P, Wightman JP, Surface characterization of plasma treated carbon fibres and adhesion to a thermoplastic pol5mer, J Adhesion, 38(1-2), 55-78, 1992. 

Phenolic polymers in many respects are ideal for microlithographic resists as they provide predictable, well-controlled dissolution behavior, excellent adhesion properties, and acceptable plasma etch resistance. But the strong absorption of phenolic polymers at 193 nm (illustrated in Fig. 8) precludes their use at that wavelength, and 193-nm resist efforts can be characterized as the pursuit of new transparent polymer systems that combine these three functional attributes as effectively as do their phenolic counterparts. 

A Systematic Study and Characterization of Advanced Corrosion Resistance Materials and Their Applications for Plasma Etching Processes in Semiconductor Silicon Wafer Fabrication... 

The revolutionary chamber materials study under high density plasma has opened a new scientific field in the characterization of materials. Meeting the comprehensive requirements of plasma etching tools in semiconductor wafer fabrication with the technology node shrinkage is not an easy task. The efforts and methodology developed through these studies have built up the foimdation in the advanced materials characterization, development and application. 

Khulbe KC, Matsuura T. Characterization of PPO membranes by oxygen plasma etching, gas separation and atomic force microscopy. J. Memb. Sci. 2000 171 273-284... 

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