Method of measuring numerical aperture of exposure machine, control wafer, photomask, and method of monitoring numerical aperture of exposure machine
AssigneeMaxchip Electronics Corp.
InventorsChien-Min Wu, Chien-Chih Chen
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Abstract
A method of measuring a numerical aperture of an exposure machine is described. A control wafer having vernier marks thereon and an aberration mask having pinholes therein are provided, wherein each pinhole corresponds to a vernier mark in position. A lithography process using the exposure machine and the aberration mask is performed to the control wafer, so as to form over each vernier mark a photoresist pattern having the same shape of the illumination pattern of the light source of the exposure machine. The numerical aperture of the exposure machine is then derived from a graduation of the vernier mark corresponding to an outer edge of the photoresist pattern.
Claims9
A method of measuring a numerical aperture (NA) of an exposure machine, wherein a light source of the exposure machine has an illumination pattern, the method comprising:
- providing a control wafer having a plurality of vernier marks thereon;
- providing an aberration mask having a plurality of pinholes therein, wherein each pinhole corresponds to a vernier mark in position;
- performing a lithography process using the exposure machine and the aberration mask to the control wafer, so as to form a photoresist pattern having the same shape of the illumination pattern over each vernier mark;
- and
- deriving the NA of the exposure machine from a graduation of the vernier mark corresponding to an outer edge of the photoresist pattern.
A method of monitoring a numerical aperture (NA) of an exposure machine, wherein a light source of the exposure machine has an illumination pattern, the method comprising:
- providing a control wafer having a plurality of vernier marks thereon;
- providing an aberration mask having a plurality of pinholes therein, wherein each pinhole corresponds to a vernier mark in position;
- setting the exposure machine according to a required NA;
- performing a lithography process using the exposure machine and the aberration mask to the control wafer, so as to form a photoresist pattern having the same shape of the illumination pattern over each vernier mark;
- deriving a real NA of the exposure machine from a graduation of the vernier mark corresponding to an outer edge of the photoresist pattern;
- comparing the real NA with the required NA and adjusting the exposure machine according to a result of the comparison;
- and
- establishing an NA database of exposure machine.
Dependencies are inferred from the claim text.