Knife edge set of mask aligner, large-view-field mask aligner, and exposure method
View Patent ↗A shutter blade assembly for a photolithography machine, a large-field of view (FoV) photolithography machine and an exposure method are disclosed. A scanning-directional shutter blade subassembly is moved once during each illuminance test and then moved above alignment marks after the test. During exposure, the scanning-directional shutter blade subassembly moves with a mask stage in the same direction and at the same speed so that it stays stationary relative to the alignment marks on a photomask ( 4 ). In case of full-FoV exposure, it is not necessary for a non-scanning-directional shutter blade subassembly to be moved, while in case of partial-FoV exposure, it is moved into the partial exposure FoV and defines there a window for obtaining a light spot with a desired shape by modulating illumination light. After that, with the non-scanning-directional shutter blade subassembly being maintained stationary, the exposure FoV can be shifted from the current exposed region to a new region to be exposed simply by moving the mask and wafer stages. This process can be repeated until all the regions to be exposed have been exposed. Since the need for multiple shutter blade assemblies is dispensed with, structural simplification can be achieved, the requirements for control accuracy can be lowered.
1. A shutter blade assembly for a photolithography machine, the shutter blade assembly being disposed within the photolithography machine, the photolithography machine being configured to perform an exposure during which a mask stage and a wafer stage move in a same direction that is defined as a scanning direction, with a direction horizontally orthogonal to the scanning direction being defined as a non-scanning direction,
wherein the shutter blade assembly comprises:
a scanning-directional shutter blade subassembly movable in the scanning direction, the scanning-directional shutter blade subassembly being configured to shade alignment marks on a photomask carried by the mask stage; and
a non-scanning-directional shutter blade subassembly movable in the non-scanning direction,
wherein a light spot of an illumination light provided by an illumination device of the photolithography machine is used for the exposure after having been trimmed by a window defined by the non-scanning-directional shutter blade subassembly,
wherein during the exposure, the scanning-directional shutter blade subassembly stays stationary relative to the alignment marks on the photomask, and the non-scanning-directional shutter blade subassembly stays stationary relative to the illumination device; and
wherein the scanning-directional shutter blade subassembly comprises a front shutter blade and a rear shutter blade extending longitudinally parallel to each other, wherein each of the front and rear shutter blades is a metal sheet extending longitudinally parallel to the non-scanning direction, and wherein the rear shutter blade has a slit extending longitudinally parallel to the non-scanning direction formed therein.
2. A large-field of view (FoV) photolithography machine for exposing multiple regions to be exposed, comprising, disposed sequentially from the top downward:
an illumination device for providing an illumination light;
a mask stage for carrying a photomask; and
a wafer stage for carrying a substrate to be scan-exposed, wherein during exposure, the wafer stage and the mask stage move in a same direction and at a same speed, the direction being defined as a scanning direction, with a direction horizontally orthogonal to the scanning direction being defined as a non-scanning direction,
the large-FoV photolithography machine further comprising:
a scanning-directional shutter blade subassembly movable in the scanning direction, the scanning-directional shutter blade subassembly being configured to shade alignment marks on the photomask; and
a non-scanning-directional shutter blade subassembly movable in the non-scanning direction,
wherein a light spot of the illumination light provided by an illumination device of the photolithography machine is used for the exposure after having been trimmed by a window defined by the non-scanning-directional shutter blade subassembly,
wherein the exposure of each of the multiple regions to be exposed is performed by keeping the scanning-directional shutter blade subassembly stationary relative to the alignment marks on the photomask and keeping the non-scanning-directional shutter blade subassembly stationary relative to the illumination device, wherein the exposure of the multiple regions to be exposed can be completed by driving the mask stage and the wafer stage to successively move the multiple regions to be exposed into an illumination FoV of the illumination device; and
wherein the scanning-directional shutter blade subassembly comprises a front shutter blade and a rear shutter blade extending longitudinally parallel to each other, wherein each of the front and rear shutter blades is a metal sheet extending longitudinally parallel to the non-scanning direction, and wherein the rear shutter blade has a slit extending longitudinally parallel to the non-scanning direction formed therein.
3. The large-FoV photolithography machine of claim 2 , wherein the scanning-directional shutter blade subassembly is disposed on a coarse-motion stage for the mask stage and is situated higher than the photomask, the scanning-directional shutter blade moving with the coarse-motion stage for the mask stage during the exposure.
4. The large-FoV photolithography machine of claim 2 , wherein a sensor is disposed under the mask stage and configured to sense the illumination light that has passed through the slit.
5. The large-FoV photolithography machine of claim 2 , wherein the scanning-directional shutter blade subassembly further comprises a first movement guide and a first driving member, the first movement guide extending longitudinally along the scanning direction, the first driving member being configured to drive the front and rear shutter blades to move along the first movement guide.
6. The large-FoV photolithography machine of claim 5 , wherein two first movement guides that are parallel to each other are provided, and wherein two ends of each of the front and rear shutter blades are moveable along the two first movement guides.
7. The large-FoV photolithography machine of claim 6 , wherein the first driving member comprises linear motors disposed at the two ends of each of the front and rear shutter blades.
8. The large-FoV photolithography machine of claim 6 , wherein decoupling devices are arranged in connections between the two ends of each of the front and rear shutter blades and the first movement guides.
9. The large-FoV photolithography machine of claim 8 , wherein the decoupling devices are cross roller rings.
10. The large-FoV photolithography machine of claim 6 , wherein blade locking devices are provided at connections between the two ends of each of the front and rear shutter blades and the first movement guides.
11. The large-FoV photolithography machine of claim 10 , wherein the blade locking devices are guide dampers configured to immobilize the front and rear shutter blades on the first movement guides.
12. The large-FoV photolithography machine of claim 6 , wherein the first movement guides are provided with respective orientation measuring devices.
13. The large-FoV photolithography machine of claim 12 , wherein the orientation measuring devices are grating scales.
14. The large-FoV photolithography machine of claim 2 , further comprising an objective lens assembly disposed between the mask stage and the substrate, the objective lens assembly comprising several objective lenses arranged in an array.
15. The large-FoV photolithography machine of claim 14 , wherein the non-scanning-directional shutter blade subassembly is disposed between the objective lens assembly and the substrate.
16. The large-FoV photolithography machine of claim 2 , wherein the non-scanning-directional shutter blade subassembly comprises four shutter blades arranged in two rows and two columns.
17. The large-FoV photolithography machine of claim 16 , wherein the shutter blades are rectangular.
18. The large-FoV photolithography machine of claim 16 , wherein the non-scanning-directional shutter blade subassembly further comprises a second movement guide and a second driving member, each extending longitudinally in the non-scanning direction, the second driving member being configured to drive the four shutter blades to move along the second movement guide so as to accomplish FoV adjustment.
19. The large-FoV photolithography machine of claim 18 , wherein two second movement guides opposing each other are provided, with each of the second movement guides supporting two of the shutter blades, the two of the shutter blades being movable along a corresponding one of the two second movement guides.
20. The large-FoV photolithography machine of claim 18 , wherein the second driving member comprises a lead screw extending parallel to the second movement guide and a rotating motor that is coupled to the lead screw, each of the shutter blades of the non-scanning-directional shutter blade subassembly is driven by the rotating motor cooperating with the lead screw.
21. An exposure method using a large-FoV photolithography machine comprising, disposed sequentially from the top downward: an illumination device for providing an illumination light a mask stage for carrying a photomask; and a wafer stage for carrying a substrate to be scan-exposed, wherein during exposure, the wafer stage and the mask stage move in a same direction and at a same speed, the direction being defined as a scanning direction, with a direction horizontally orthogonal to the scanning direction being defined as a non-scanning direction, the large-FoV photolithography machine further comprising: a scanning-directional shutter blade subassembly movable in the scanning direction, the scanning-directional shutter blade subassembly being configured to shade alignment marks on the photomask; and a non-scanning-directional shutter blade subassembly movable in the non-scanning direction, wherein a light spot of the illumination light provided by an illumination device of the photolithography machine is used for the exposure after having been trimmed by a window defined by the non-scanning-directional shutter blade subassembly, wherein the exposure of each of the multiple regions to be exposed is performed by keeping the scanning-directional shutter blade subassembly stationary relative to the alignment marks on the photomask and keeping the non-scanning-directional shutter blade subassembly stationary relative to the illumination device, wherein the exposure of the multiple regions to be exposed can be completed by driving the mask stage and the wafer stage to successively move the multiple regions to be exposed into an illumination FoV of the illumination device, the exposure method of claim 2 , comprising the steps of:
1) prior to exposure, performing an illuminance test for a region to be exposed by moving the scanning-directional shutter blade subassembly over the region to be exposed in the scanning direction;
2) moving the non-scanning-directional shutter blade subassembly over the region to be exposed and defining, by the non-scanning-directional shutter blade subassembly, a window for trimming an illumination light;
3) moving the mask stage and the wafer stage in a same direction and moving the scanning-directional shutter blade subassembly with the mask stage so that the scanning-directional shutter blade subassembly is stationary relative to alignment marks on the photomask and the non-scanning-directional shutter blade subassembly is stationary relative to the illumination device, thereby exposing the region to be exposed; and
4) moving a new region to be exposed into an illumination FoV of the illumination device by moving the mask stage and the wafer stage and repeating step 1) to step 3) to expose the new region to be exposed,
wherein in step 2), the illuminance test for the region to be exposed performed by moving the scanning-directional shutter blade subassembly over the region to be exposed in the scanning direction comprises: fixing the front shutter blade above the alignment areas, while moving the rear shutter blade in the scanning direction and receiving, by a sensor disposed under the mask stage, the illumination light that has successively passed through a slit in the rear shutter blade and the mask stage; and deriving illuminance data for the region to be exposed from the received illumination light.
22. The exposure method of claim 21 , wherein the photomask comprises two alignment areas distributed in symmetry and several pattern areas arranged in an array, the two alignment areas distributed at respective ends of the photomask, each of the pattern areas corresponding to a region to be exposure.
23. The exposure method of claim 22 , wherein the scanning-directional shutter blade subassembly comprises a front shutter blade and a rear shutter blade, and wherein during exposure, the front and rear shutter blades are positioned above the respective alignment areas to block the illumination light away from the alignment areas.