Method and apparatus for irradiating a microlithographic substrate
View Patent ↗A method and apparatus for exposing a radiation-sensitive material of a microlithographic substrate to a selected radiation. The method can include directing the radiation along a radiation path in a first direction toward a reticle, passing the radiation from the reticle and to the microlithographic substrate along the radiation path in a second direction, and moving the reticle relative to the radiation path along a reticle path generally normal to the first direction. The microlithographic substrate can move relative to the radiation path along a substrate path having a first component generally parallel to the second direction, and a second component generally perpendicular to the second direction. The microlithographic substrate can move generally parallel to and generally perpendicular to the second direction in a periodic manner while the reticle moves along the reticle path to change a relative position of a focal plane of the radiation.
1. A method for exposing a radiation-sensitive material of a microlithographic substrate to a selected radiation, the radiation-sensitive material having a layer of photoresist material with an outer surface and an inner surface, the method comprising:
directing a radiation beam along a radiation path through a reticle toward the microlithographic substrate, the beam having a beam width at the microlithographic substrate; and
forming an image on the microlithographic substrate and the layer of photoresist material with the beam while simultaneously moving the reticle along a reticle path generally normal to the radiation path and moving the microlithographic substrate relative to the radiation path along a substrate path, the substrate path having a first component generally parallel to the radiation path and a second component generally perpendicular to the radiation path, wherein the microlithographic substrate moves generally parallel to and generally perpendicular to the radiation path toward and away from the reticle in a manner correlated with the width of the beam and the motion of the reticle while the reticle moves along the reticle path, and wherein forming an image on the layer of photoresist material includes impinging a focal plane of the radiation beam passing through the reticle on the photoresist material, the focal plane being movable between a first position at or proximate to the outer surface of the photoresist material and a second position at or proximate to the inner surface of the photoresist material.
2. The method of claim 1 , further comprising impinging the focal plane of the radiation beam on one or more intermediate portions of the layer of photoresist material between the outer surface and the inner surface.
3. The method of claim 1 wherein moving the microlithographic substrate includes oscillating the microlithographic substrate in a periodic manner toward and away from the reticle along an axis generally parallel to the radiation path as the microlithographic substrate and the reticle move relative to each other.
4. The method of claim 3 wherein moving the microlithographic substrate in a periodic manner includes moving the microlithographic substrate for an integer number of periods during the time the microlithographic substrate moves transverse to the beam by a distance of one beam width or about one beam width.
5. The method of claim 1 wherein moving the microlithographic substrate includes simultaneously moving the microlithographic substrate generally parallel to and generally perpendicular to the radiation path.
6. The method of claim 1 wherein moving the microlithographic substrate includes moving the microlithographic substrate along a curved path.
7. The method of claim 1 wherein moving the microlithographic substrate includes moving the microlithographic substrate along a straight path having a first segment directed toward the reticle and a second segment directed away from the reticle.
8. The method of claim 1 wherein moving the microlithographic substrate includes moving the microlithographic substrate along a path describing a square wave.
9. The method of claim 1 wherein moving the microlithographic substrate includes moving the microlithographic substrate along a path describing a sinusoidal wave.
10. The method of claim 1 wherein moving the microlithographic substrate includes moving the microlithographic substrate along a path describing a periodic, triangular profile.
11. The method of claim 1 wherein moving the reticle includes moving the reticle in a direction opposite to the second component of motion of the microlithographic substrate.
12. The method of claim 1 wherein a reduction lens is positioned between the reticle and the microlithographic substrate, and wherein the method further comprises moving the reduction lens axially relative to the microlithographic substrate to move a focal plane of the radiation beam axially relative to the microlithographic substrate.
13. The method of claim 12 wherein moving the reduction lens axially relative to the microlithographic substrate comprises varying the axial position of the focal plane between the outer layer and the inner layer of the photoresist material.
14. The method of claim 1 , further comprising selecting the radiation beam to have a wavelength of from about 13 nanometers or less to about 365 nanometers.
15. The method of claim 1 , further comprising orienting a plane of the reticle and a plane of the microlithographic substrate approximately normal to the radiation path while simultaneously moving the reticle along the reticle path the microlithographic substrate along the substrate path.
16. A method for exposing a radiation-sensitive material of a microlithographic substrate to a selected radiation, the method comprising:
directing a radiation beam along a radiation path through an aperture in a reticle and to the microlithographic substrate, the beam having a beam width at least proximate to an intersection between the beam and the microlithographic substrate;
focusing the radiation beam toward a focal plane; and
impinging the focal plane of the radiation beam on the microlithographic substrate while simultaneously moving (a) the reticle relative to the radiation path along a reticle path generally normal to the radiation path, and (b) the microlithographic substrate relative to the radiation path and the focal plane along a substrate path, the substrate path having a first component generally parallel to the radiation path and a second component generally perpendicular to the radiation path, wherein the microlithographic substrate oscillates in a periodic manner toward and away from the reticle along an axis generally parallel to the radiation path for an integer number of periods during the time the microlithographic substrate moves transverse to the radiation beam by a distance of approximately one beam width.
17. The method of claim 16 , further comprising selecting the radiation-sensitive material to include a layer of photoresist material having a thickness, and wherein:
impinging the focal plane of the radiation beam on the microlithographic substrate comprises impinging the focal plane on one or more depth-wise layers within the thickness of the layer of photoresist material.
18. The method of claim 17 wherein the layer of photoresist material includes a first depth-wise layer and a second depth-wise layer, and wherein impinging the focal plane on one or more depth-wise layers comprises impinging the focal plane on the first layer for a first period of time and impinging the focal plane on the second layer for a second period of time different than the first period of time as the reticle and the microlithographic substrate move relative to each other.
19. The method of claim 16 wherein moving the microlithographic substrate along the substrate path includes moving the microlithographic substrate along a path describing a sinusoidal wave.