• This etched patterned polysilicon wafer is designed to make it easier to calibrate automated metrology tools. It also doubles up as a monitor wafer for metrology performance evaluation and tracking.
  
  
• MetroCal is available in 200 mm and 300 mm wafer sizes.
  
  
• Each field on a MetroCal wafer has a thousand different features for one-dimensional and two-dimensional calibrations.
  
  
• Stage Mapping - Since their introduction in 2003, MetroCal wafers have been adopted by several equipment manufacturers as the XY stage mapping artifact of choice. Stage movement accuracy of 1 micron or better is achievable for metrology tool stages. Information about MetroCal specifications for stage mapping is provided on a separate page.
  
  
• NIST Certification - MetroCal patterns include two long gratings for length scale calibration in X and Y directions. The length scales (grating pitches) of these two features on one field of one particular wafer were certified by the National Institute of Standards and Technology (NIST) using the large scale interferometer. The uncertainties in certification of average pitch over the length of these gratings were extremely tight, about 5 parts per million for deviation of average length scale from the ideal.
  
  
• Traceability - The length scales of the same two gratings in any field on all other wafers are traceable to those of the certified pair of gratings within the uncertainties derived from tolerances in the manufacturing process (provided, of course, that the particular instance of each feature is defect free).
  
  
• Design of MetroCal emphasizes calibration of CD-SEM systems in semiconductor manufacturing. MetroCal provides a comprehensive set of targets organized on a single substrate for calibration of SEM tools. Targets are designed for calibration of SEM and optical image scale at several magnifications, stage map (XY), wafer center, optical microscope center to SEM center offset, SEM and optical image skew and aspect ratio, zoom center, scan shift and other system calibrations required for automated, recipe-driven operation in manufacturing facilities.
  
  
• Multiple system matching is the main benefits of consistent calibration from tool to tool. Matching includes recipe sharing and transportability among tools (i.e. a single recipe or database that runs on all tools) and metrology results matching.
  
  
• MetroCal is processed in a state-of-the-art semiconductor fabrication facility. Compared to the calibration artifacts mounted on stages of individual systems, MetroCal offers the advantage of being transportable from tool to tool for improved multiple system matching. In addition, MetroCal resembles product wafers more closely than artifacts that are either mounted on stages or glued in a pocket wafer configuration.
  
  
• MetroCal can also be used for monitoring CD metrology tool performance. All small measurement targets have fiducials nearby for use as pattern recognition templates in automated recipes. The wafer is exposed with deep UV resist process with minimum guaranteed feature size of 260 nm pitch (1:1 nominal Line:Space) for 200 mm wafers and 240 nm pitch for 300 mm wafers. Patterns on MetroCal include smaller isolated lines and spaces down to about 100 nm lines on 200 mm wafers and 80 nm lines on 300 mm wafers. Etched features have nearly vertical sidewalls resulting in small apparent beam width (ABW) in top-down SEM images.
  
  
• MetroCal wafer is compatible with wet and dry cleaning procedures used at gate level in semiconductor manufacturing.
  
  

For more information, check out MetroCal Brochure, a list of MetroCal™ applications and capabilities, or
Download its pdf file (172kB).

Documents are available for download as pdf (Portable Document Format) files. To view these files, you will need Adobe™ Acrobat™ Reader which is downloadable from Adobe web