Patent ID: 7655384

Claim:
A method for determining a spherical aberration associated with a photoresist material, comprising: irradiating the photoresist material with a light having a spherical aberration of zero at a first focal distance in the photoresist material; measuring the spherical aberration of the light in the photoresist material at the first focal distance; irradiating the photoresist material with the light having a spherical aberration of zero at least at one alternative focal distance; measuring the spherical aberration of the light in the photoresist material at the at least at one alternative focal distance; and determining the spherical aberration associated with the photoresist material based at least partially on the measured spherical aberration of the light in the photoresist material at the first focal distance and the measured spherical aberration of the light in the photoresist material at the at least one alternative focal distance.