Optics: measuring and testing – Inspection of flaws or impurities – Surface condition
Reexamination Certificate
2002-08-23
2004-08-10
Stafila, Michael P. (Department: 2877)
Optics: measuring and testing
Inspection of flaws or impurities
Surface condition
C250S492200, C250S492220
Reexamination Certificate
active
06774990
ABSTRACT:
BACKGROUND
Inspection of patterns on both semiconductor wafers and masks used in lithographic processing is extremely important to ensure successful device fabrication. Even minute irregularities in a pattern can result in a nonfunctioning device.
Optical inspection is commonly used for inspection of masks and semiconductor wafers. Optical inspection systems focus ultraviolet (UV) or deep ultraviolet (DUV) light onto the pattern surface and collect the transmitted or reflected light signals to form an image of the pattern. Shorter wavelength light sources allow resolution of smaller feature sizes than longer wavelength light sources. However, light sources of wavelengths below 200 nm that also provide the necessary power and repetition rate for use in an inspection system are not readily available. Therefore, the minimum resolvable feature size of such systems typically is limited to approximately 100 nm for defects. Some optical inspection using high numerical aperture (NA) optics and/or improved inspection algorithms.
Scanning electron beam inspection is another inspection technology. Scanning electron beam inspection systems focus electron beams from an electron gun and scan the beams across the surface of a pattern. An image is formed by collecting secondary electrons emitted from the surface. The use of reflected electrons (rather than photons) allows electron beam inspection systems to resolve significantly smaller pattern feature sizes than are resolved by optical inspection systems. For example, some scanning electron inspection systems resolve minimum pattern feature sizes on the order of 50 nm for primary features and defects. However, electron beam inspection systems generally are much slower than optical systems and, as a result, electron beam inspection typically is used in wafer sampling rather than in the 100% wafer inspection needed during wafer processing.
REFERENCES:
patent: 4626101 (1986-12-01), Ogawa et al.
patent: 4694170 (1987-09-01), Slodzian et al.
patent: 4843329 (1989-06-01), Beha et al.
patent: 5118952 (1992-06-01), Sakamoto et al.
patent: 5122737 (1992-06-01), Clauberg
patent: 5150043 (1992-09-01), Flesner
patent: 6048745 (2000-04-01), Landers et al.
patent: 6172363 (2001-01-01), Shinada et al.
patent: 6215128 (2001-04-01), Mankos et al.
patent: 6291833 (2001-09-01), Landers et al.
R.H. Watts et al., “Measuring ultrashort laser pulses in the time-frequency domain using frequency-resolved optical gating”, Review of Scientific Instruments, vol. 68, No. 9, (1997) pp. 3464-3476.
David E. Seeger, “Electron-Beam, X-Ray, EUV, and Ion-Beam Submicrometer Lithographies for Manufacturing VI”, Int'l. Society for Optical Engineering, SPIE vol. 2723, 11-13 Mar. 1996, pp. 211-220.
Liang Ted
Stivers Alan R.
Tejnil Edita
Fish & Richardson P.C.
Intel Corporation
Nguyen Sang H.
Stafila Michael P.
LandOfFree
Method to inspect patterns with high resolution photoemission does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method to inspect patterns with high resolution photoemission, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method to inspect patterns with high resolution photoemission will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3282001