Calibration methods and devices useful in semiconductor photolithography

A method for calibrating a photolithography system, the method comprising:

• producing a light from an illumination source;
• producing a static refraction from the light, the static refraction being non-shifting with respect to a defocus shift of the illumination source;
• producing a dynamic refraction from the light, the dynamic refraction being able to shift in response to the defocus shift of the illumination source;
• and
• exposing a photoresist on a microelectronic substrate to the static and dynamic refraction in a single exposure.

A photolithography system, comprising:

• an illumination source configured to produce a generally coherent light with a single frequency (λ);
• a substrate support facing the illumination source, the substrate support being configured to support a microelectronic substrate;
• a reticle between the illumination source and the substrate support, the reticle having a first grating pattern and a second grating pattern adjacent to the first grating pattern;
• an objective lens between the substrate support and the reticle, and
• wherein the first grating pattern has a first pitch (P1) generally equal to a value calculated as follows:
• P
• 1
• =
• λ
• 2
• 
• 
• NA
• source
• where (NAsource) is a numerical aperture of the illumination source;
• and
• wherein the second grating pattern has a second pitch (P2) different than the first pitch (P1).