Applications
Electron microscopy - SEM, in both SE and BSE mode, SEM/FIB and TEM (with special version)
Scanning Microscopies and Profilometry - STM, AFM, the pattern height is 100nm
Optical Microscopy - transmitted, reflected, bright/dark field, differential contrast and confocal
Chemical mapping - EDS, WDS, XRF, XPS, Auger and others. The pattern is fabricated using 100nm CrO2 and Cr on quartz
Particle Size Counting - series of circles, squares & rectangles for calibration confirmation
Pattern Design
The MRS-4 is fabricated using the high accuracy direct write electron beam manufacturing equipment. The pattern is anti-reflective chromium (30nm Cr2O over 70nm Cr) on quartz. Imaging in both secondary and back scattered mode is very high. The pattern is coated with a proprietary conductive material which allows for SEM imaging at any accelerating voltage.

Geometric design
The MRS-4 has groups of nested squares with pitches of 1/2µm, 1µm, 2µm, 50µm and 500µm. The largest pattern has an overall dimension of 8mm square with lines and spaces of 250µm. This can be used to check magnifications between 10 - 100x. The 50µm pitch patterns are useful from 100 - 1000x magnifications. The 2, 1 and 1/2µm pitch patterns allow calibrations up to 200,000x. Incorporated into the standard are X & Y rulers with 6mm length with 1µm increments.

Dimensions
The overall size is approx. 9mm x 9mm x 2.3mm thick. The MRS-4 can be provided in an aluminum retainer with a size of 25mm diameter and 3mm thickness to protect the standard.


Optional Protective Retainer 614-5 and Optional Pin Stub Mounting 614-62 Optical Microscope Adapter OM/R 614-6

This is the most popular retainer and is usable for SEM and transmitted light applications. A special version of the MRS-4 is available for TEM which has a 3mm diameter and a 500µm thickness.

Accuracy
Measurements by the NPL in the UK (counterpart of NIST) have demonstrated that the accuracy of the 500µm was ±0.25µm, and ± 0.1µm for the 50µm and 2µm patterns. The 1µm and 1/2µm patterns have an accuracy of ±0.04µm.

Certification report
The certification is done following ISO guidelines. Each MRS-4 has a unique serial number engraved on the standard. Certification includes the serial number, certification date, operator, instrumentation used, actual pattern measurements and measure of accuracy. The recertification due date is also given.

NIST = National Institute of Standards and Technology, USA

NPL = National Physical Laboratories, UK (counterpart of NIST)