Lithography machine and scanning and exposing method thereof
The present disclosure provides a lithography machine and a scanning and exposing method thereof. According to the scanning and exposing method, the scanning and exposing process for a whole wafer includes two alternately circulated motions: a scanning and exposing motion and a stepping motion; and the scanning and exposing motion is a sinusoidal motion rather than a rapid-acceleration uniform-speed rapid-deceleration scanning and exposing motion in the conventional techniques. During the scanning of a single exposure shot, it may begin to scan the exposure shot once a wafer stage and a reticle stage begin to accelerate from zero speed. And the scanning and exposing may not end until the speeds of the wafer stage and the reticle decrease to zero. Therefore, the effective time of the scanning and exposing in the scanning and exposing motion is greatly increased and the production efficiency of the wafer is improved.
1. A scanning and exposing method for a lithography machine containing a wafer stage carrying a wafer to be exposed and a reticle stage carrying a reticle mask, a region on the wafer to be exposed being divided into two or more exposure shots, the method comprising:
stepping the wafer stage to a first exposure shot;
moving the wafer stage and the reticle stage synchronously in opposite directions respectively for scanning and exposing the first exposure shot, wherein:
during the scanning and exposing of the first exposure shot, the speed curves of the wafer stage and the reticle stage are sinusoidal curves, and magnitudes of the speeds of the wafer stage and the reticle stage gradually increase from zero to maximum values and then decrease to zero respectively,
the ratio of the magnitude of the speed of the wafer stage to the magnitude of the speed of the reticle stage is equal to a ratio of a size of a pattern finally is formed on the wafer to a size of a pattern of the reticle mask, and
during the scanning and exposing of the first exposure shot, a light intensity, of a light source for exposing, and the magnitudes of the speeds of the wafer stage and the reticle stage change synchronously, and a variation curve of magnitude of the light intensity versus time is a sinusoidal curve.
2. The scanning and exposing method according to claim 1 , wherein the wafer stage is stepped to a second exposure shot after the first exposure shot is scanned and exposed, and the wafer stage and the reticle stage move synchronously in different directions respectively, to scan and expose the second exposure shot.
3. The scanning and exposing method according to claim 1 , wherein the wafer stage and the reticle stage are driven by a long-range motion motor into which a cosine signal is input, during the scanning and exposing of the first exposure shot, so that the speed curves of the wafer stage and the reticle stage are sinusoidal curves.
4. The scanning and exposing method according to claim 3 , wherein the positions of the wafer stage and the reticle stage are detected by an interferometer or a scale in real-time, during the scanning and exposing of the exposure shot, so as to obtain actually output displacements and speeds of the reticle stage and the wafer stage, and the wafer stage and the reticle stage are driven by a short-range motion motor according to actually output displacements and speeds of the reticle stage and the wafer stage, so as to correct the speeds and displacements of the wafer stage and the reticle stage in real-time.
5. The scanning and exposing method according to claim 1 , wherein the lithography machine is an immersion lithography machine.
6. A lithography machine, comprising:
a light source configured to provide a light beam having a light intensity, a variation curve of magnitude of the light intensity versus time being a sinusoidal curve;
an optical system;
a reticle stage configured to carry a reticle mask;
an object lens system configured to project the light beam onto a wafer coated with photoresist, the object lens system comprising more than one lens;
a wafer stage configured to carry the wafer; and
a signal generator configured to ensure that the reticle stage and the wafer stage move synchronously in opposite directions at a speed whose speed curve is a sinusoidal curve, wherein the light intensity and magnitudes of the speeds of the wafer stage and the reticle stage change synchronously.
7. The lithography machine according to claim 6 , wherein the lithography machine further comprises a liquid immersion control device which is configured to fill the space between a last lens of the object lens system and the wafer with liquid.
8. The lithography machine according to claim 6 , wherein the lithography machine further comprises a long-range motion motor connected with the signal generator, the long-range motion motor is connected to the reticle stage and the wafer stage respectively and is configured to drive the reticle stage and the wafer stage, so that the speed curves of the wafer stage and the reticle stage are sinusoidal curves.
9. The lithography machine according to claim 8 , wherein the lithography machine further comprises an interferometer or a scale and a short-range motion motor, the interferometer or the scale is configured to detect the positions of the wafer stage and the reticle stage in real time, and the short-range motion motor is connected to the wafer stage and the reticle stage and is configured to drive the reticle stage and the wafer stage, so as to correct speeds and displacements of the wafer stage and the reticle stage in real-time.