Profilometers

Another application of laser-based profilometry is the inspection of rocket and missile components. The U.S. Air Force has funded work to develop a non-contact laser-based profilometer for the inside surface of solid rocket motors. Over time, these devices are subject to slumping and cracking, which could potentially render the rocket motor ineffective and hazardous. When fully implemented, this system will provide a meaningful screening method for evaluating the condition of aging rocket motors. 

The three-dimensional, quantitative nature of STM and SFM data permit in-depth statistical analysis of the surface that can include contributions from features 10 nm across or smaller. By contrast, optical and stylus profilometers average over areas a few hundred A across at best, and more typically a pm. Vertical resolution for SFM / STM is sub-A, better than that of other profilometers. STM and SFM are excellent high-resolution profilometers. 

STM and SFM are free from many of the artifacts that afflict other kinds of profilometers. Optical profilometers can experience complicated phase shifts when materials with different optical properties are encountered. The SFM is sensitive to topography oidy, independent of the optical properties of the surface. (STM may be sensitive to the optical properties of the material inasmuch as optical properties are related to electronic structure.) The tips of traditional stylus profilometers exert forces that can damage the surfaces of soft materials, whereas the force on SFM tips is many orders of magnitude lower. SFM can image even the tracks left by other stylus profilometers. 

The three-dimensional, digital nature of SFM and STM data makes the instruments excellent high-resolution profilometers. Like traditional stylus or optical profilometers, scanning probe microscopes provide reliable height information. However, traditional profilometers scan in one dimension only and cannot match SPM s height and lateral resolution. 

Every material sputters at a characteristic rate, which can lead to significant amb ity in the presentation of depth profile measurements by sputtering. Before an accurate profile can be provided, the relative sputtering rates of the components of a material must be independently known and included, even though the total depth of the profile is normally determined (e.g., by stylus profilometer). To first order, SNMS offers a solution to this amb ity, since a measure of the total number of atoms being sputtered from the surface is provided by summing all RSF- and... 

The significance of instrument band width and modulation transfer function was discussed in connection with Equation (3) to characterize the roughness of nominally smooth surfaces. The mechanical (stylus) profilometer has a nonlinear response, and, strictly speaking, has no modulation transfer function because of this. The smallest spatial wavelength which the instrument can resolve, 4nin> given in terms of the stylus radius rand the amplitude aoi the structure as... 

R, D. Jacobson, S. R. Wilson, G. A. Al-Jumaily, J. R, McNeil, and J. M. Bennett. Microstructure Characterization by Angle-Resolved Scatter and Comparison to Measurements Made by Other Techniques. To be published in AppL Opt. This work discusses the band width and modulation transfer function of the scatterometer, stylus profilometer, optical pro-filometer, and total integrated scattering systems, and gives results of mea suring several surhices using all techniques. 

S. R, Wilson, G. A. Al-Jumaily, and J. R. McNeil. Nonlinear Characteristics of a Stylus Profilometer. Opt. Eng. 26,953, 1987. This describes modeling stylus profilometer response characteristics and explains their shortcomings. 

Profilpriifer, m. profilometer. projektieren, v.t. project plan, design purpose. 

In this section, two t5q)ical engineering surfaces, a ground surface and a shaved surface, are employed for the comparison. The original roughness data were measured with an optical profilometer, but the roughness amplitude has been rescaled for the convenience of computation. In simulations, a relatively small load of 50 N is applied to guarantee that asperities will not be completely flattened while other operation conditions are listed in Table 4. 

A Dektak siuface profilometer was used to measure the etch rates. The profiles of the etched films were observed by field emission scanning electron microscopy (FESEM). In addition, x-ray photoelectron spectroscopy PCPS) was utilized to examine the existence of possible etch products or redeposited materials, and to elucidate the etch mechanism of Co2MnSi magnetic films in a CVOa/Ar plasma. 

Surface roughness was measured according to ANSI standard 1346.1-(1978) using a Tencor Instruments Alpha-Step 200 stylus profilometer located at the National Nanofabrication Facility of Cornell. Five surface roughness measurements were made for each sample and their average values recorded. Details of the experimental apparatus set-up and its operation are given elsewhere (Dems, B. C. et. al. Inti. Polvm. Proc.. in press.). 

Surface Roughness measured with Tencor Instruments Alpha-Step 200 stylus profilometer per ANSI Standard 1346.1-(1978)... 

We first experimented with the Quartz Crystal Microbalance (QCM) in order to measure the ablation rate in 1987 (12). The only technique used before was the stylus profilometer which revealed enough accuracy for etch rate of the order of 0.1 pm, but was unable to probe the region of the ablation threshold where the etch rate is expressed in a few A/pulse. Polymer surfaces are easily damaged by the probe tip and the meaning of these measurements are often questionable. Scanning electron microscopy (21) and more recently interferometry (22) were also used. The principle of the QCM was demonstrated in 1957 by Sauerbrey (22) and the technique was developed in thin film chemistiy. analytical and physical chemistry (24). The equipment used in this work is described in previous publications (25). When connected to an appropriate oscillating circuit, the basic vibration frequency (FQ) of the crystal is 5 MHz. When a film covers one of the electrodes, a negative shift <5F, proportional to its mass, is induced ... 

Davis et al. reported the successful etching of PTFE using single-photon energies in the quartz UV (308 nm and a pulse duration of 25 ns) by sensitizing the fluoropolymer with polyimide. 72 The number of pulses varied depending on fluence and material composition in order to achieve ablated features whose depths were reproducible as measured by a stylus-type profilometer. The pulse repetition rate was on the order of about 200 Hz. In that study, dopant levels... 

In this application, the process analyzer is used in the vis-NIR spectral region to measure the clear top layer on a co-extruded polymer film. The bottom layer is pigmented to an opaque white color and its thickness cannot be determined by this method. Prior to the installation of the fiber-optic spectroscopy system, film samples were measured manually in the laboratory by a subtractive scheme. First, the total thickness of a sample was measured on a manual profilometer. The top layer of the polymer was removed with methylene chloride. The sample was then repositioned on the profilometer as closely as possible to the originally measured spot and the thickness of the second white layer was determined. The thickness of the top layer was then determined by difference. 

It is clear that a very important measurement both from a technological and mechanistic point of view is the rate at which a surface is etched or the rate at which a polymer film is deposited in a plasma. Essentially all studies of etching or polymerizing plasmas include etching or polymerization rate measurements. Many of these measurements have required that the substrate be removed from the plasma system Often the substrates are carefully weighed before and after exposure to the plasma and often a profilometer is used to measure the step height... 

B. Dimensional Stability Boroscope Miniaturized T.V. Microscope Radiation Reflectance or Diffraction Photocell (visible) X-ray diffraction U.V. reflectance spectroscope y-Ray back-scatter Scintillation read out Infrared reflectance Radiation emission Infrared scan Profilometer... 

Fig. 31. Effect of surface texture. Roughness values were determined with a diamond-tipped profilometer. The data are from Fig. 30 (C4).

X-Ray diffraction was performed on a M03X-HF22 diffractometer (MAC Science) using Mn filtered Fe Ka radiation. The thickness of the films was determined with a surface profilometer (Kosaka Laboratory Co., SE 1700). Absorption spectra of the films were recorded on a Shimadzu UV-3100PC spectrophotometer. Nitrogen adsorption isotherm was obtained on a BELSORP TCV (BEL Japan Inc.) system. 

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