Reticle transmittance measurement method, projection exposure method using the same, and projection exposure device
When a reticle is first used, the reticle is loaded in a projection exposure device and measured by either oblique measurement or random measurement, thereby avoiding the fear of uneven sampling and determining the reticle transmittance of the entire reticle as the parent population, without increasing the sampling count. The same effect can be obtained by making the measurement spot size, which is fixed in general, variable and by changing the angle of incidence in relation to the measurement spot size.
1. A reticle transmittance measurement method for a projection exposure device configured to project a pattern of a reticle onto a wafer to obtain a given pattern on the wafer,
the reticle transmittance measurement method comprising:
determining sampling pitches in an X-direction and a Y-direction to have a random value within a predetermined range instead of having a fixed value, to thereby set the sampling pitches so as to match with a different pattern of a reticle pattern that has a same repetition pitch, and not to match with a same pattern of the reticle pattern that has the same repetition pitch.
2. A projection exposure method, comprising performing exposure load correction based on a reticle transmittance that is determined by the reticle transmittance measurement method of claim 1 .
3. A projection exposure method according to claim 2 , wherein the exposure load correction comprises at least one of focus correction, lens distortion correction, or magnification correct.
4. A projection exposure device configured to measure a reticle transmittance using sampling and to project a pattern of a reticle onto a wafer to obtain a given pattern on the wafer,
wherein, in the sampling, sampling pitches in an X-direction and a Y-direction have a random value within a predetermined range instead of having a fixed value, to thereby set the sampling pitches so as not to match with a reticle pattern that has a repetition pitch but to have a reticle pattern that has different pitches.