Alignment systems and methods for lithographic systems
An alignment system for a lithographic apparatus has a source of alignment radiation; a detection system that has a first detector channel and a second detector channel; and a position determining unit in communication with the detection system. The position determining unit is constructed to process information from said first and second detector channels in a combination to determine a position of an alignment mark on a work piece, the combination taking into account a manufacturing process of the work piece. A lithographic apparatus has the above mentioned alignment system. Methods of alignment and manufacturing devices with a lithographic apparatus use the above alignment system and lithographic apparatus, respectively.
1. A method of automatic process control for the manufacture of microdevices, comprising: receiving data from an alignment mark detection system having a plurality of detector channels; determining an updated processing strategy based on said received data from said alignment mark detection system; and altering a processing step based on said updated processing strategy, wherein said plurality of detector channels of said alignment mark detection system provide a corresponding plurality of signals substantially simultaneously during detection of an alignment mark.
2. A method of automatic process control according to claim 1 , wherein said data from said alignment mark detection system is obtained from a scan of a multitarget alignment mark.
3. A method of automatic process control according to claim 2 , wherein said multitarget alignment mark comprises at least two targets separately detectable by said alignment mark detection system to provide detection signals in corresponding at least two detector channels of said plurality of detector channels.
4. A method of automatic process control according to claim 3 , wherein said at least two targets are each diffraction-order-enhancing gratings that enhance different diffraction orders, the corresponding at least two detector channels being diffraction-order channels.
5. A method of automatic process control according to claim 2 , wherein at least one of said at least two targets of said multitarget alignment mark is a process target that changes a signal characteristic in a substantially predictable manner during steps of processing said microdevice.
6. A method of automatic process control according to claim 5 , wherein said process target is a diffraction grating having a substructure of cross trenches filled with tungsten.
7. A method of automatic process control according to claim 3 , wherein at least one of said at least two targets of said multitarget alignment mark is a diffraction grating formed over a layer of material opaque to alignment radiation directed thereon, said layer of opaque material acting to tune an effective depth of said diffraction grating.
8. A method of automatic process control according to claim 2 , wherein said multitarget alignment mark comprises at least four targets formed along a scribe line of a semiconductor wafer.
9. A method of automatic process control according to claim 1 , wherein said alignment mark detection system is an off-axial alignment system of a lithographic exposure apparatus.
10. A method of automatic process control according to claim 9 , further comprising: receiving data from an off-line metrology tool; and determining said updated processing strategy based on said received data from said alignment mark detection system and said data from said off-line metrology tool.
11. A method of automatic process control according to claim 1 , wherein at least two channels of said plurality of detector channels correspond to detection at different wavelengths.
12. An automatic process control system for the manufacture of microdevices, comprising: a data processing unity adapted to receive data from an alignment mark detection system having a plurality of detector channels, wherein said data processing unit determines an updated processing strategy based on data received from said alignment mark detection system and outputs a signal to alter a processing step based on said updated processing strategy, and wherein said plurality of detector channels of said alignment mark detection system provide a corresponding plurality of signals substantially simultaneously during detection of an alignment mark.
13. An automatic process control system according to claim 12 , wherein said data from said alignment mark detection system is obtained during a scan of a multitarget alignment mark.
14. An automatic process control system according to claim 13 , wherein said multitarget alignment mark comprises at least two targets separately detectable by said alignment mark detection system to provide detection signals in corresponding at least two detector channels of said plurality of detector channels.
15. An automatic process control system according to claim 14 , wherein said at least two targets are each diffraction-order-enhancing gratings that enhance different diffraction orders, the corresponding at least two detector channels being diffraction-order channels.
16. An automatic process control system according to claim 14 , wherein at least one of said at least two targets of said multitarget alignment mark is a process target that changes a signal characteristic in a substantially predictable manner during steps of processing said microdevice.
17. An automatic process control system according to claim 16 , wherein said process target is a diffraction grating having a substructure of cross trenches filled with tungsten.
18. An automatic process control system according to claim 14 , wherein at least one of said at least two targets of said multitarget alignment mark is a diffraction grating formed over a layer of material opaque to alignment radiation directed thereon, said layer of opaque material acting to tune an effective depth of said diffraction grating.
19. An automatic process control system according to claim 13 , wherein said multitarget alignment mark comprises at least four targets formed along a scribe line of a semiconductor wafer.
20. An automatic process control system according to claim 12 , wherein said alignment mark detection system is an off-axial alignment system of a lithographic exposure apparatus.
21. An automatic process control system according to claim 20 , wherein said data processing unit is further adapted to receive data from an off-line metrology tool, and said data processing unit determines said updated processing strategy based on data received from said alignment mark detection system and said off-line metrology tool and outputs said signal to alter said processing step based on said updated processing strategy.
22. An automatic process control system according to claim 12 , wherein at least two channels of said plurality of detector channels correspond to detection at different wavelengths.
23. A method of automatic equipment control for the manufacture of microdevices, comprising: receiving data from an alignment mark detection system having a plurality of detector channels; determining an updated processing strategy based on said received data from said alignment mark detection system; and altering a processing step based on said updated processing strategy, wherein said plurality of detector channels of said alignment mark detection system provide a corresponding plurality of signals substantially simultaneously during detection of an alignment mark.
24. A method of automatic equipment control according to claim 23 , wherein said data from said alignment mark detection system is obtained during a scan of a multitarget alignment mark.
25. A method of automatic equipment control according to claim 24 , wherein said multitarget alignment mark comprises at least two targets separately detectable by said alignment mark detection system to provide detection signals in corresponding at least two detector channels of said plurality of detector channels.
26. A method of automatic equipment control according to claim 25 , wherein said at least two targets are each diffraction-order-enhancing gratings that enhance different diffraction orders, the corresponding at least two detector channels being diffraction-order channels.
27. A method of automatic equipment control according to claim 26 , wherein at least one of said at least two targets of said multitarget alignment mark is a process target that changes a signal characteristic in a substantially predictable manner during steps of processing said microdevice.
28. A method of automatic equipment control according to claim 27 , wherein said process target is a diffraction grating having a substructure of cross trenches filled with tungsten.
29. A method of automatic equipment control according to claim 25 , wherein at least one of said at least two targets of said multitarget alignment mark is a diffraction grating formed over a layer of material opaque to alignment radiation directed thereon, said layer of opaque material acting to tune an effective depth of said diffraction grating.
30. A method of automatic equipment control according to claim 24 , wherein said multitarget alignment mark comprises at least four targets formed along a scribe line of a semiconductor wafer.
31. A method of automatic equipment control according to claim 23 , wherein said alignment mark detection system is an off-axial alignment system of a lithographic exposure apparatus.
32. A method of automatic equipment control according to claim 23 , wherein at least two channels of said plurality of detector channels correspond to detection at different wavelengths.