Claims
- 1. A system for detecting particles on a substrate-supporting chuck comprising:
- an inspection subsystem for analyzing a surface of a chuck to determine if any particles are thereon, said inspection subsystem including
- a laser for projecting a laser beam on the surface of the chuck, and
- a light detector for receiving and detecting scattered light from the laser beam after reflecting off a particle on the surface of the chuck;
- a moveable table for holding the chuck to be inspected and for moving the chuck during inspection; and
- a control unit coupled to the inspection subsystem and moveable table, the control unit for moving the moveable table to allow the inspection subsystem to inspect the surface of the chuck and to produce an indication signal if a particle is detected on the surface of the chuck.
- 2. A system for detecting particles on a substrate-supporting chuck comprising:
- an inspection subsystem for analyzing a surface of a chuck to determine if any particles are thereon, said inspection subsystem including
- a camera;
- a video-to-digital converter coupled to the camera for digitizing a first captured image to produce a first digital signal of the first captured image;
- a moveable table for holding the chuck to be inspected and for moving the chuck during inspection, and
- a control unit coupled to the inspection subsystem and moveable table, the control unit for moving the moveable table to allow the inspection subsystem to inspect the surface of the chuck and to produce an indication signal if a particle is detected on the surface of the chuck.
- 3. The system of claim 2, wherein the control unit comprises a microprocessor operable to perform the following steps:
- comparing the first digital signal of the first captured image to a second digital signal of a second captured image to identify differences; and
- sounding an alarm if differences between the first digital signal and the second digital signal are greater than a predetermined threshold.
- 4. The system of claim 2, wherein the control unit comprises:
- (1) a display, and
- (2) a microprocessor operable to perform the following steps:
- (i) compare the first digital signal of the first captured image to a second digital signal of a clean chuck to identify differences; and
- (ii) provide an indication if differences between the first digital signal and the second digital signal are greater than a predetermined threshold.
- 5. The system of claim 1 further comprising:
- a precision driving device coupled to the moveable table for precisely moving the moveable table; and
- an electronics subsystem coupled to the control unit for executing commands from the control unit.
- 6. A method for detecting a particle on a substrate-supporting chuck of photolithography equipment, the method comprising the steps of:
- providing an inspection subsystem;
- using a moveable table associated with a stepper to move a substrate-supporting chuck, relative to the inspection subsystem; and
- using the inspection subsystem and moveable table to inspect a surface of the substrate-supporting chuck to locate any particles thereon including the steps of:
- projecting a laser beam onto a surface of a substrate-supporting chuck;
- locating a light detector at a predetermined location to capture and detect scattered light from the laser beam after it reflects off a particle on the surface of the chucks;
- moving the moveable table to cause the laser beam to pass over substantially all of the surface of the chuck; and
- indicating the presence of a particle if any instances are observed where the light detector receives the scattered light.
- 7. The method of claim 6, wherein the step of using the inspection subsystem and moveable table to inspect a surface of the substrate-support chuck for particles comprises the step of:
- recording the location of any particles indicated in said step of indicating the presence of a particle.
- 8. A method for detecting a particle on a substrate-supporting chuck of photolithography equipment, the method comprising the steps of:
- providing an inspection subsystem; and
- using a moveable table associated with a stepper to move a substrate-supporting chuck, relative to the inspection subsystem; and
- using the inspection subsystem and moveable table to inspect a surface of the substrate-supporting chuck to locate any particles thereon, wherein said step of using the inspection subsystem and moveable table to inspect a surface of the substrate-support chuck for particles comprises the steps of:
- capturing a video image of the surface of the chuck;
- converting the video image to a first digital signal;
- comparing the first digital signal with a template digital signal of a clean chuck; and
- indicating any differences between the first digital signal and the template digital signal.
- 9. The method of claim 8, wherein the step of using the inspection subsystem and moveable table to inspect a surface of the substrate-support chuck for particles further comprises the step of:
- recording the location of any differences indicated in said step of indicating any differences greater than a predetermined threshold between the first digital signal and the template digital signal.
- 10. A method of manufacturing a system for detecting particles on a substrate-supporting chuck of photolithography equipment comprising the steps of:
- forming an inspection subsystem for analyzing a surface of a chuck to determine if any particles are thereon, said step including
- forming a laser-scatter subsystem having a laser for projecting a laser beam on the surface of the chuck, and
- forming a light detector for receiving and detecting scattered light if a particle is encountered by the laser beam;
- forming a moveable table for holding the chuck to be inspected and for moving the chuck; and
- coupling a control unit to the inspection subsystem and moveable table for moving the moveable table to allow the inspection subsystem to inspect the surface of the chuck and to produce a warning signal if a particle is detected on the surface of the chuck.
- 11. A method of manufacturing a system for detecting particles on a substrate-supporting chuck of photolithography equipment comprising the steps of:
- forming an inspection subsystem for analyzing a surface of a chuck to determine if any particles are thereon, wherein the step of forming the inspection subsystem comprises the step of forming a video-based inspection subsystem having a camera and a video-to-digital converter coupled to the camera for digitizing a first captured image to produce a first digital signal of the first captured image;
- forming a moveable table for holding the chuck to be inspected and for moving the chuck; and
- coupling a control unit to the inspection subsystem and moveable table for moving the moveable table to allow the inspection subsystem to inspect the surface of the chuck and to produce a warning signal if a particle is detected on the surface of the chuck.
- 12. The method of claim 11, wherein the step of forming the inspection subsystem further comprises the step of:
- programming the control unit to perform the following steps:
- comparing the first digital signal of the first captured image to a second digital signal to identify differences, and
- providing an indication signal if differences between the first digital signal and the second digital signal are greater than a predetermined threshold.
- 13. The method of claim 10 further comprising the steps of:
- coupling a precision driving device to the moveable table for precisely moving the moveable table; and
- forming an electronics subsystem coupled to the control unit for executing commands from the control unit.
- 14. The system of claim 1, wherein:
- said laser is disposed to project said laser beam to the surface of said chuck at a predetermined angle;
- wherein said system further comprises a beam stop disposed relative to said predetermined angle in the path of said laser beam as directly reflected off the surface of said chuck; and
- said light detector is disposed relative to said predetermined angle off the path of said laser beam as directly reflected off the surface of said chuck.
- 15. The method of claim 6, wherein:
- said step of projecting the laser beam onto the surface of the substrate-supporting chuck projects the laser beam at a predetermined angle;
- said method further comprises the step of disposing a beam stop relative to said predetermined angle in the path of said laser beam as directly reflected off the surface of the substrate-supporting chuck; and
- said step of locating the light detector to capture and detect scattered light from the laser beam after it reflects off a particle on the surface of the chucks disposes said light detector relative to said predetermined angle off the path of said laser beam as directly reflected off the surface of the substrate-supporting chuck.
- 16. The method of claim 10, wherein:
- said step of forming a laser-scattering subsystem projecting the laser beam onto the surface of the chuck projects the laser beam at a predetermined angle;
- said method further comprises the step of
- disposing a beam stop relative to said predetermined angle in the path of said laser beam as directly reflected off the surface of the chuck; and
- disposing said light detector relative to said predetermined angle off the path of said laser beam as directly reflected off the surface of the chuck.
Parent Case Info
This application claims priority under 35 USC 119(e) (1) of provisional application number 60/033,110, filed Dec. 17, 1996.
US Referenced Citations (6)