Above is the picture of a Surface Topography Reference, model STR10.   The image above shows a top-down view of one of the grid clusters taken with an optical microscope. 3D AFM MEASUREMENTS THAT STAND OUT The Surface Topography Standard (STR) is designed as an auxiliary aid for sophisticated imaging tool monitoring include Atomic Force Microscopes (AFM) measurement. The Surface Topography Reference's versatile design incorporates features defined in all three spatial directions, allowing correct imaging and the monitoring of the instrument's linearity and long term stability. The Surface Topography Reference It also offers valuable information about the piezoelectric functions, sample alignment as well as stylus integrity and condition. Surface Topography References (STR) Product Description The Surface Topography Reference consists of an 8 mm x 8 mm silicon die with a precisely fabricated silicon dioxide pitch cluster. The cluster area is located in the center of the die and contains a grid pattern with a 3 µm pitch in a 1.2 mm x 1.2 mm measurement area (STR3), or 10 µm pitch in a 4 mm x 4 mm measurement area (STR10). The grid pattern consists of an array of alternating bars and spaces with extremely uniform pitch in both the x and y directions. The entire surface topography of the die is coated with a very uniform (nominally 40 nm) layer of platinum, making it versatile for both conductive and non conductive probing techniques. Surface Topography References (STR) Product Specifications Dimensions 8 mm x 8 mm silicon die Materials Silicon Dioxide on Silicon coated with Platinum (except 180 nm models) Nominal Pitch Values (X and Y) 3 µm, 10 µm Nominal Height values (Z) 18 nm, 44 nm, 100 nm, 180 nm Traceability Reference only (not traceable)