Reticle particle calibration standards

Methods and apparatus are described for reticle particle calibration standards. A method includes making a reticle particle calibration standard including depositing a solution that includes a plurality of particles onto a first plate; drying the solution to evaporate a solvent; bonding the plurality of particles to the first plate; coupling a second plate to the first plate, the plurality of particles located between the first plate and the second plate, wherein the plurality of particles include a plurality of traceable standard particles of substantially known shape and size. An apparatus includes a reticle particle calibration standard including a first plate; a second plate coupled to the first plate, wherein the second plate is substantially parallel to and coincident with the first plate; and a plurality of traceable standard particles of substantially known shape and size i) located between the first plate and the second plate and ii) bonded to at least one plate selected from the group consisting of the first plate and the second plate. A method includes using a reticle particle calibration standard to qualify a metrology instrument or monitor performance of the metrology instrument including: scanning the reticle particle calibration standard using the metrology instrument; compiling a raw data map of the reticle particle calibration standard; comparing the raw data map to a calibration data map associated with the reticle particle calibration standard.