Precise SEM Cross Section Polishing via Argon Beam Milling

Abstract

SEM observation of a specimen cross section can provide important information for research and development as well as failure analysis. In most cases, surface observation alone cannot provide information concerning the cross sectional structure of granular materials, layered materials, fibrous materials, and powders. Preparing highly-polished cross sections of these materials is both a science and an art.Typically, a cross section is prepared using mechanical means like conventional mechanical polishing methods or a microtome. The sample is first embedded in a holder or device, and then polished to achieve a flat cross section. In some cases, a staining procedure is used to highlight a specific component of the sample. Such methods can be lengthy procedures that require a great deal of skill, and can introduce artifacts into soft materials, deform the material around voids, or compress layers of soft and hard materials in composite samples. Mechanical polishing can miss fine details such as the presence of hairline cracks, and present a challenge to water-soluble phases.In other cases, a Focused Ion Beam (FIB) System is used when precise positioning of the cross section is required, such as in the case 2. Gold wirebond cross section prepared using the CP. The inset shows magnified view of grain structure and voids.of stacks of thin films or micro area specimen preparation. However, the size of the resulting cross section is limited, and the heavy gallium ions in the beam can damage the sample surface.A new precision argon ion beam cross section polisher simplifies the preparation of samples and makes it possible to prepare truly representative cross sections of samples free of artifacts and distortion. Use of the broad argon ion beam eliminates the problems associated with conventional polishing and allows for larger specimens to be prepared with precision. (1,2) The JEOL Cross Section Polisher (CP) consists of a specimen chamber with a turbo pump vacuum system, an optical microscope for specimen positioning, and controls for the vacuum system and stationary ion beam (Fig. 1). The specimen stage in the chamber features a holder and masking plate.To produce a cross section using the CP, the specimen is placed in the holder, and the region of the sample to be cross sectioned is selected under the optical microscope. The masking plate is placed across the selected region. After evacuating the specimen chamber, • miOROJCOPY TODflY May 2006COMPO 5.0kV X7.0003. Toner particles cross section prepared using the CP.

Permeability anisotropy and resistivity anisotropy of mechanically compressed mudrocks

“…This process results in a flat surface with only minor topographic variations. Because this method is not a mechanical polishing process, it does not have the disadvantages of incorporating abrasives into the final surface and does not alter materials that are sensitive to heat (Erdman et al, 2006).…”

Separating macrostresses from microstresses in Al2O3–15vol%SiC particulate reinforced composites

“…Ion beam milling provides an opportunity to produce surfaces that are nearly free of artifacts and distortions produced by conventional cutting and grinding processes [11]. Therefore, ion beam milling may be a method to minimize residual surface stresses without annealing.…”

Imaging pore space in tight gas sandstone reservoir: insights from broad ion beam cross-sectioning

“…However, this technique induces potentially more damage to the surface since it uses mainly Gallium source ( [7]) and typical areas produced by FIB (about µm 2 ) are much smaller than those prepared by BIB (about mm 2 ). Thus, the combination of Ar-BIB and SEM facilities provides an efficient method to get a direct access to porosity and allowing its detailed understanding.…”

“…Firstly, air-dried core samples were sub-sampled by slow cutting with a miniature diamond saw using air as cooling medium.. A flat surface of these samples of about 1cm 3 was cross-sectioned perpendicular to the diamond-cut surface, using a stand-alone argon beam machine (cross-section polisher JEOL SM-09010, [7]) to produce high quality polished cross-sections of about 2 mm 2 . We used 6 kV voltage achieving currents of about 150-200 nA.…”