System and method for photomask particle detection

1. A method of fabricating a semiconductor device, the method comprising:

performing a photolithography process, wherein the performing the photolithography process includes:

using a photomask to pattern a radiation beam;

exposing a target substrate to the patterned radiation beam; and

during the exposing the target substrate, monitoring for particles on the photomask by sending a light beam from a light source to a detector and detecting a change in intensity of the light beam using the detector.

2. The method of claim 1 , wherein the detecting the change in intensity of the light beam is performed on the light beam traversing a region adjacent the photomask surface.

3. The method of claim 1 , wherein the monitoring for particles includes

sending an intensity of the light beam detected at the detector to a processor to perform the detecting the change in intensity.

4. The method of claim 3 , further comprising:

determining a size of a particle using the sent intensity of the light beam.

5. The method of claim 2 , further comprising:

determining a position of a particle on the photomask using the change in intensity of the light beam.

6. The method of claim 1 , further comprising:

providing a particle monitor including the light source and the detector of at least one dark field detector and at least one bright field detector.

7. The method of claim 1 , wherein the exposing the target surface includes using a radiation beam having a wavelength in an extreme ultraviolet (EUV) range.

8. A method of fabricating a semiconductor device, comprising:

providing a photomask having patterned surface and defined by a first, second, third and fourth edges;

positioning a light source adjacent the first edge of the photomask and adjacent and spaced a distance from the patterned surface of the photomask;

positioning an optical detector adjacent the second edge of the photomask;

sending a light beam from the light source to the optical detector; and

using the optical detector to determine an energy loss of the light beam between the light source and the optical detector.

9. The method of claim 8 , wherein the second edge is an opposing edge of the photomask to the first edge.

10. The method of claim 8 , wherein the light beam extends over the first, second, third and fourth edges.

11. The method of claim 8 , further comprising:

providing a radiation beam to the patterned surface of the photomask;

reflecting the radiation beam from the patterned surface; and

using the reflected beam to pattern a photosensitive layer disposed on a semiconductor substrate.

12. The method of claim 11 , wherein the providing the radiation beam and the sending the light beam are concurrent.

13. The method of claim 8 , further comprising:

using a second optical detector to determine an occurrence of energy from a reflection of the light beam off a particle disposed between the light source and the optical detector.

14. The method of claim 8 , further comprising:

using the determined energy loss to identify a particle disposed on or adjacent the patterned surface of the photomask; and

using the determined energy loss to determine at least one of the particle's size, the particle's shape, and the particle's position.

15. A method of fabricating a semiconductor device, comprising:

providing a photomask having patterned surface and defined by a first, second, third and fourth edges;

positioning a light source adjacent the first edge of the photomask and adjacent and spaced a distance from the patterned surface of the photomask;

positioning a monitor system adjacent the second edge of the photomask;

sending a light beam from the light source to the monitor system; and

using the monitor system to determine if a particle exists on the photomask by determining a change in intensity of the light beam.

16. The method of claim 15 , wherein using the monitor system includes identifying an interference of the light beam to determine if a particle exists on the photomask.

17. The method of claim 15 , wherein using the monitor system uses dynamic light scatter technology to detect particles.

18. The method of claim 15 , wherein using the monitor system includes identifying an energy loss or gain of the light beam to determine if a particle exists on the photomask.

19. The method of claim 18 , wherein the monitor system uses an optical sensor.