The PELCO® Tripod Polisher™ 590 was designed by researchers at the IBM East Fishkill Laboratory* to accurately prepare TEM and SEM samples of pre-specified, micron-sized regions. For TEM samples, this technique has been used successfully to limit ion milling times to less than 15 minutes and, in some cases, has eliminated the need for ion milling. Although this technique was designed for preparing semiconductor cross-sections, it has been used to prepare both plan-view and cross-section samples from such diverse materials as ceramics, composites, metals, and geological samples.
Features & Benefits
- Precise cross-sectioning at the TEM level
- Repeatable and rapid production of TEM samples
- Reduces ion milling time to minutes as opposed
to hours
- Produces large thin areas over the entire
specimen
Operation - Standard Technique
The PELCO® Tripod Polisher™ 590 can be used to prepare a sample for both SEM and TEM cross-sectional analysis. To accomplish this, the sample is mounted on the face of a special SEM stub which is clamped into the slotted L-bracket of the PELCO® Tripod Polisher™ 590. Initial grinding is done on a 15μm metal bonded diamond disc. Further lapping and polishing continues with a succession of diamond films ranging in size from 30μm to 0.5μm. The final polish is done with a colloidal silica suspension. As lapping progresses, the two rear micrometers are used to adjust the plane of polish. With periodic examinations in an inverted microscope, the plane of polish is adjusted until it is parallel to the plane of interest. At this point the SEM stub may be moved to an ion mill for a quick milling to remove fine scratches, polishing debris and to give the surface topography prior to SEM analysis. The SEM stub can be mounted directly in the SEM for analysis. When analysis is complete, a TEM sample of the same area is made. The sample is removed from the SEM stub and attached to a single aperture TEM grid. The slotted L-bracket is removed and the TEM grid is attached to the round sample mount which is affixed to the center of the polisher. The sample is now mechanically thinned using Diamond Lapping Film. During this process the sample is periodically examined in an inverted microscope and the micrometers are adjusted to maintain the correct plane of polish. The sample is final polished using a polishing disc and colloidal silica to 1μm or less and then ion milled for up to 15 minutes.
Operation - Wedge Technique
Wedge polishing technique can be used either in conjunction with ion milling (common for cross-sections) or electropolishing, or in some cases where preferential thinning, amorphization, and topography that can occur in ion-milled samples is unacceptable, mechanically polish the sample to electron transparency. With this technique the SEM stub is replaced, in the slotted L-bracket, with a Pyrex® insert. The sample is mounted on the bottom of the insert and the two rear micrometers are adjusted and the micrometer nearest the sample is retracted to produce a wedge shape as material is removed from the sample. The typical wedge angle is 1.5-2 degrees. The sample, with the features of interest at the apex of the wedge, is thinned until the area of interest is 3-5um thick if final polishing by other methods or ~1μm thick if mechanically finishing, on a succession of diamond lapping films. The sample is then final polished, either mechanically on a final polishing cloth such as our MultiTex Cloth (#816-12) with a colloidal silica suspension, or glued to a single aperture TEM grid and removed from the Pyrex® insert for final polishing by other methods. |