What is ISO 21466 - CDSEM about ?
ISO 21466 specifies the structure model with related parameters, file format, and fitting procedure for characterizing critical dimension (CD) values for wafer and photomask by imaging with a critical dimension scanning electron microscope (CD-SEM) by the model-based library (MBL) method. The method is applicable to linewidth determination for specimens, such as gate on wafer, photomask, single isolated or dense line feature pattern down to the size of 10 nm. 
Who is ISO 21466 - CDSEM for ?
 ISO 21466 on method for evaluating critical dimensions by CDSEM is useful for: 
- Manufacturers of semiconductors
- Quality control laboratories
- Microbeam imaging practitioners
- Nanostructures researchers
 Why should you use ISO 21466 - CDSEM ?  
CD-SEMs (critical dimension scanning electron microscopes) is one of the main tools for CD measurement in semiconductor manufacturing processes, where secondary electrons (SEs) are the signal source for CD-SEM imaging of surface structure.
ISO 21466 employs the model-based library (MBL) method for accurate CD determination by CD-SEM. The MBL method provided in ISO 21466 is superior to simpler, unsophisticated, arbitrary methods that disregard the physics of signal generation, and report only a meagre number, potentially with unacceptably high bias. ISO 21466 provides results with less bias and better size and shape accuracy.
