Stylus profilers

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... 

Thickness Measurement. The thickness of poly(I) at different coverages was obtained using a Tencor alpha-step 100 surface profile measuring system. Electrodes used were glass slides coated with Pt by electron beam evaporation. In order to produce a "step" across which the stylus of the surface profiler was drawn, Apiezon N grease was applied to part of the electrode surface and was removed with CH2CI2 after derivatization with poly(I). 

An excellent way to create standards is ion implantation of the elements of interest into the matrix. This works exceptionally well for semiconductors since one can usually start with high-purity single-crystal materials that represent the matrix of interest. Also the use of Eq. (4.8) is well suited for this purpose since ion implanters usually quote doses in atoms per square centimeter. However, Eq. (4.5) serves just as well by converting the matrix concentration to atoms per cubic centimeter. In this procedure, the implant profile is sputtered through, the implant element secondary ions and the matrix element secondary ions are each summed, and the depth of the sputter profile is determined, usually by using a stylus profilome-ter. The sensitivity factor is then calculated from... 

Surface Analysis. The resist etching process was studied by measuring changes in the resist thickness versus etching time using a mechanical stylus surface profiler (Alpha-Step 200, Tencor Instruments, Inc.). 

Samples returned to the laboratory after exposure are measured by micrometer prior to laser-moire evaluation micrometer measurements are reproducible only to within 13 micrometers because surface roughness produces an unusually high sensitivity of measurements to placement of the micrometer. Following laser-moire measurements, the samples have in some instances been checked by an electronic dial gage profiling technique. Because there is risk of damage to samples by the stylus of the gage, its use is minimized thus, the statistics are fewer than desired and far less comprehensive than those of the completely nondestructive laser-moire method. Samples are returned to test sites for continued exposure after measurements. 

ISO 3274 1996 Geometrical Product Specifications (GPS) — Surface texture Profile method — Nominal characteristics of contact stylus instruments. 

DIN EN ISO 3274 1998-04 (1998) Geometrical product specification (GPS). Surface texture Profile method Nominal characteristics of contact (stylus) instruments. 

Figure 12-5 is schematic real surface profiles do not have the regular periodicity shown there, nor is the position of the reference line automatically determined. The CLA or the RMS surface roughness is a statistically calculated quantity, to obtain which raw data must be suitably processed. Figure 12-6 shows schematically (with a surface profile of unrealistic ruggedness for convenience in illustrating the point) the kind of problem encountered with a stylus probe instrument. 

The reference line xx is established by the skid as it slides along supported by the crests of the peaks meanwhile the profile of the surface is generated by the vertical excursions of the stylus, yy, in conjunction with the horizontal movement in the x-direction. To convert these raw data into a statistical average with a symmetrically distributed deviation, the reference line xx must be translated so that the area bounded by the profile curve over the length L is equally distributed on both sides of the line, as in Fig. 12-5. Statistical treatments of surface profile data are discussed at length in Sections 12.3 and 12.4. 

For the measurement of machined surfaces, mostly two-dimensionally working tactile stylus instruments are applied. At this a stylus tip (as a rule made of diamond) is moved along the surface, and its displacement against a reference plane is measured. The obtained profile finally is treated mathematically. On mild surfaces, the stylus tip may leave marks, which is a disadvantage of tactile measuring methods. 

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