Claims Analysis
Total Claims: 15
Claim 1
Independent Claim
100 words
An optical system for making thickness measurements of a subarea of a patterned wafer, said system comprising: light producing means for providing light to illuminate the patterned wafer; low resolution imaging means for imaging the wafer at a first predetermined resolution to create a low resolution image of the wafer at a focal plane; high resolution imaging means for imaging a subarea of the wafer at a relatively high predetermined resolution to create a high resolution image of the subarea and; processor means for determining the thickness of the subarea using data derived from the high and low resolution images.
Claim 2
Dependent Claim
100 words
An optical system for making thickness measurements of a subarea of a patterned wafer, said system comprising: light producing means for providing light to illuminate the patterned wafer; low resolution imaging means for imaging the wafer at a first predetermined resolution to create a low resolution image of the wafer at a focal plane; high resolution imaging means for imaging a subarea of the wafer at a relatively high predetermined resolution to create a high resolution image of the subarea and; processor means for determining the thickness of the subarea using data derived from the high and low resolution images.
Claim 3
Dependent Claim
22 words
The optical system of claim 1 further comprising a cofocal optical system for focussing the high resolution image at the focal plane.
Claim 4
Dependent Claim
40 words
The optical system of claim 2 wherein the high resolution imaging means is selected from the firoup consisting of a sparse array of lenses and a scanning lens that is adapted to focus an image onto an image producing means.
Claim 5
Dependent Claim
28 words
The optical system of claim 3 wherein the image producing means comprises a camera and a zoom lens that is adapted to focus an image onto the camera.
Claim 6
Dependent Claim
262 words
An optical system that is adapted to make film thickness measurements of a patterned wafer, said system comprising: a high intensity spectrally filtered light source; a fiber optic bundle optically coupled to the light source for transmitting light provided thereby; a lens group optically coupled to the fiber optic bundle for receiving the light transmitted thereby; a collimating lens optically coupled to the lens group for collimating the light transmitted thereby; a diffuser optically coupled to the collimating lens for causing the light to scatter therefrom to provide a diffused light source; a beamsplitter optically coupled to the diffuser for reflecting light onto the patterned wafer; a CCD array; a zoom lens for imaging light reflected from the wafer at a first predetermined low resolution onto the CCD to provide a low resolution wafer image in an object plane; a moveable cofocal optical system disposed between the wafer and the zoom lens for imaging a small area of the wafer at a second predetermined resolution that is higher than the resolution of the zoom lens to provide a high resolution image in the same object plane as the wafer image; and a processor coupled to the CCD array that comprises a library containing reflectance values that correspond to different values of film thickness that are recalculated at different wavelengths, and wherein the processor comprises means for determining a reflectance of the wafer using the high and low resolution images, and means for comparing the computed reflectance to the precalculated values to determine the thickness of the film of the wafer corresponding thereto.
Claim 7
Dependent Claim
262 words
An optical system that is adapted to make film thickness measurements of a patterned wafer, said system comprising: a high intensity spectrally filtered light source; a fiber optic bundle optically coupled to the light source for transmitting light provided thereby; a lens group optically coupled to the fiber optic bundle for receiving the light transmitted thereby; a collimating lens optically coupled to the lens group for collimating the light transmitted thereby; a diffuser optically coupled to the collimating lens for causing the light to scatter therefrom to provide a diffused light source; a beamsplitter optically coupled to the diffuser for reflecting light onto the patterned wafer; a CCD array; a zoom lens for imaging light reflected from the wafer at a first predetermined low resolution onto the CCD to provide a low resolution wafer image in an object plane; a moveable cofocal optical system disposed between the wafer and the zoom lens for imaging a small area of the wafer at a second predetermined resolution that is higher than the resolution of the zoom lens to provide a high resolution image in the same object plane as the wafer image; and a processor coupled to the CCD array that comprises a library containing reflectance values that correspond to different values of film thickness that are recalculated at different wavelengths, and wherein the processor comprises means for determining a reflectance of the wafer using the high and low resolution images, and means for comparing the computed reflectance to the precalculated values to determine the thickness of the film of the wafer corresponding thereto.
Claim 8
Dependent Claim
18 words
The optical system of claim 5 wherein the high intensity spectrally filtered light sottree comprises a halogen lamp.
Claim 9
Dependent Claim
18 words
The optical system of claim 5 wherein the lens group comprises a concave lens and a convex lens.
Claim 10
Dependent Claim
23 words
The optical system of claim 7 wherein the high intensity spectrally filtered light source comprises a motor drive coupled to a filter wheel.
Claim 11
Dependent Claim
20 words
The optical system of claim 8 wherein the filter wheel is disposed between the concave lens and the convex lens.
Claim 12
Dependent Claim
31 words
The optical system of claim 8 wherein the motor drive and filter wheel is adapted to insert one of a plurality of filters between the concave lens and the convex lens.
Claim 13
Dependent Claim
12 words
The optical system of claim 5 wherein the collimating lens comprises plastic.
Claim 14
Dependent Claim
14 words
The optical system of claim 5 wherein the diffuser comprises a ground glass plate.
Claim 15
Dependent Claim
27 words
The optical system of claim 5 wherein the processor is adapted to determine the thickness of the film of the wafer using a least squares fitting technique.