Variable overlap method and device for stitching together lithographic stripes
The technology disclosed relates to variable tapers to resolve varying overlaps between adjacent strips that are lithographically printed. Technology disclosed combines an aperture taper function with the variable overlap taper function to transform data and compensate for varying overlaps. The variable taper function varies according to overlap variation, including variation resulting from workpiece distortions, rotor arm position, or which rotor arm printed the last stripe. Particular aspects of the present invention are described in the claims, specification and drawings.
1. A method of transforming pattern data used to control exposing radiation to compensate for varying overlap between adjoining printed stripes, the method including:
representing a tapered aperture by a first taper function;
representing interaction between the tapered aperture and a variable overlap between adjoining stripes by a second varying taper function that varies with the variable overlap;
wherein the second varying taper function takes into account which particular arm among a plurality of rotating arms will be used to write the transformed pattern data: and
transforming pattern data that is used to control exposure of at least one stripe, using a computer to apply a combination of the first taper function and the second varying taper function to the pattern data and outputting to memory transformed pattern data.
2. The method of claim 1 , further including retrieving data representing positions of the adjoining stripes from memory and calculating the second varying taper function from at least the positions.
3. The method of claim 1 , further including retrieving data representing overlap of the adjoining stripes from memory and calculating the second varying taper function from at least the overlap.
4. The method of claim 1 , further including retrieving data representing distortion of a workpiece for memory and calculating the second varying taper function from at least the distortion.
5. The method of claim 1 , further including retrieving data representing a position or angle of a rotating arm from memory and calculating the second varying taper function from at least the overlap.
6. The method of claim 1 , further including calculating the second varying taper function in real time as the transformed pattern data is used to control the exposure.
7. A pattern transformation device that compensates for varying overlap between adjoining printed stripes, the pattern transformation device including:
a memory;
a first filter representing a tapered aperture stored in the memory;
at least one processor coupled to said memory;
a first module running on the processor that updates a second variable overlap filter according to overlap between adjoining stripes of pattern data;
a second module running on the processor that combines the first and second filters to transform pattern data to compensate for the overlap between the adjoining stripes and output the transformed pattern data; and
a third module running on the processor that retrieves data representing a position or angle of a rotating arm, wherein the first module updates the second filter using at least the rotating arm data.
8. The device of claim 7 , further including data in the memory representing positions of the adjoining strips, wherein the first module retrieves data representing the positions and updates the second variable overlap filter using at least the positions data.
9. The device of claim 7 , further including data in the memory representing overlap of the adjoining stripes, wherein the first module retrieves data representing the overlap and updates the second variable overlap filter using at least the overlap data.
10. The device of claim 7 , further including data in the memory representing distortion of a workpiece, wherein the first module retrieves data representing the distortion of the workpiece and updates the second variable overlap filter using at least the distortion data.
11. The device of claim 7 , further including an arm used sensor coupled to the processor, wherein the first module updates the second variable overlap filter using at least arm used data from the arm used sensor.
12. The device of claim 7 , wherein the first module updates the second variable overlap filter as the second module transforms the pattern data and outputs the transformed pattern data.