Etching rate analysis

The chemical etch rate of a material by an etchant depends on the solution temperature, surface area (him morphology), residual him stress, him microstructure, stoichiometry, and the soluhon strength. It also dq)cnds on how fast the etch products arc removed from the surface and from the vicinity of the surface (i.e. agitahon). Gradahon of him properties through the thickness can also affect the etch rate. Chemical etch rates are primarily used as comparahve tests. Figure 11.7 shows a typical etch rate analysis and Table 3.11 Usts chemical etchants for a number of materials many more are to be found in the literature. 

Figure 11.7 Typical Etch Rate Analysis (Etch Rate of Si3N4 vs. Bias During Deposition)...

This leads to an efficient and non-destructive in situ etch rate measurement technique which does not require any prior knowledge of film properties. The analysis can also be used to semi-quantitatively gauge the degree of "roughening" imparted to a polymer film surface during RIE processing. 

An analysis (55) of the loading effect, which has been extended (59) to include multiple etchant loading and other etchant loss processes, indicates that the etch rate (R) for N wafers each of area A is given by... 

Most isotropic etchants exhibit a loading effect, wherein a measurable depletion of the active etchant results from consumption in the etch process. In these cases, the overall etch rate depends upon the area of film to be etched. Under extreme circumstances, with carbon-based etch gases, etchant depletion can be so severe that polymer deposition occurs instead of etching. An analysis (85) of the loading effect, which has been extended (86) to include multiple etchant loading and other etchant loss processes, indicates that the etch rate (R) for N wafers each of area A is given by... 

Batterman (31) has attempted to explain the appearance of facets on hillocks in terms of only the measured orientation dependence of the etch rate. Using this, he concluded that the 322 planes are stable hillock facets on germanium etched with an HF + H2O2 + mixture. Irving (32) in a further analysis... 

Optimum design method for this material is presented, which is based on theoretical analysis for copolymer sensitivity and on dry etch rate dependence on polymer structure obtained by a series of experiments. A resist with high sensitivity (DUl H C /cm ), high resolution (<0.5 m) and high dry erch resistance was obtained. 

Example 4 selectivity and uniformity of etching rates at a chemical vapor deposition unit that produces silicon wafers Example 5 analysis of the operation of an activated sludge wastewater treatment unit or of an entire pulp plant... 

Analysis of structure of plasma treated membrane. To analyze the chemical structures of the membrane surface treated by plasma. X-ray photoelectron spectroscopy (XPS) was used. XPS spectra were measured with a Shimadzu electron spectrometer 750 employing MgKa excitation radiation. The Au4f core level at 84 eV was used for energy calibration. The structure of the inside of treated membranes was also analyzed by X S after etching the membrane surface with Ar. The etching rate was about 50 A/min. 

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