Abstract: A method and apparatus for moving an article relative to and between a pair of distance sensing probes of a thickness measuring apparatus which are spaced apart a known distance D is described. In the method, the article is moved relative to and between the pair of probes in at least one direction in a plane normal to a common measurement axis Ac between the probes. A distance a along the common measurement axis Ac between the first probe and a point on the surface of the article nearest to the first probe of the pair that intersects the common measurement axis Ac is measured. A similar distance b between the second probe and the article is measured.

Abstract: A layer thickness determination system (10) is employed for detecting a thickness of at least one layer (12a) disposed over a surface of a wafer (13) having one or more first regions characterized by circuit and other features, and one or more second regions characterized by an absence of circuit and other features. The system includes an optical system (14) having an optical axis (14a) for collecting light reflecting from the at least one layer and the surface of the wafer. The system further includes a camera (16) coupled to the optical system for obtaining an image from the collected light; a first light source (22) for illuminating the layer with light that is directed along the optical axis and within the cone of acceptance angles; and at least one second light source (18) for illuminating the layer with light that is directed off the optical axis and outside of the cone of acceptance angles.

Abstract: Systems for making thickness measurements in a thin film structure using an incoherently or coherently coupled structured surface. A system is used to measure the thickness of a thin film layer of a thin film structure in which polished and structured surfaces are coherently coupled together. Visible light used to measure the thickness of thin bonded wafers that have a ground upper surface, or infrared light is used to measure the thickness of thick silicon wafers where one surface is ground, and the other is polished. Other systems use a structured surface that is incoherently coupled to a thin film structure in order to illuminate the thin film structure at many angles. The systems produce interference fringes that are detected and recorded, and multispectral pattern matching is used in a computer to compute film thickness based on scattering characteristics included in a library f stored interference patterns.

Abstract: An optical system for providing low and high resolution images of a patterned wafer to provide for film thickness measurements thereof. The optical system comprises a spectrally filtered light source for providing light to illuminate the wafer. A low resolution imaging system is provided for imaging the wafer at a relatively low resolution. A high resolution imaging system is provided for imaging a subarea of the wafer at a relatively high resolution to create an enlarged image in the same object plane as the wafer. An image producing system is provided for producing a visual image of the wafer derived from the low and high resolution images. The high resolution imaging system uses subaperture optical elements, comprising either a small scanning lens or a sparse array of lenses, to image small areas of the wafer at higher resolution, and the subaperture optical elements create an enlarged image in the same object plane as the actual wafer.

Abstract: A measurement instrument which detects the thickness of the outer layer of a wafer 24, includes a filtered white light source forming an aperture image. The white light source includes a halogen lamp 10, a condensing lens 12, a circular aperture 14, a collimator lens 16, a narrow band filter wheel 18, and a second collimator lens 20. A monochromatic beam generated by this filtered white light source illuminates the entire surface of the wafer 24 with collimated light that has passed through a third collimator lens 22. The light reflected off the wafer 24 returns through the third collimator lens 22 and forms an aperture image upon an optical device which redirects this image to a charge coupled device (CCD) camera 30. The image is converted to a map of measured reflectance data by a digitizing circuit 34 and a computer 36. This map of measured reflectance data is then self-normalized and compared to reference reflectance data to generate a map of the outer layer thickness profile of the wafer 24.

Abstract: A measurement instrument which detects the thickness of the outer layer of a wafer 24, includes a filtered white light source forming an aperture image. The white light source includes a halogen lamp 10, a condensing lens 12, a circular aperture 14, a collimator lens 16, a narrow band filter wheel 18, and a second collimator lens 20. A monochromatic beam generated by this filtered white light source illuminates the entire surface of the wafer 24 with collimated light that has passed through a third collimator lens 22. The light reflected off the wafer 24 returns through the third collimator lens 22 and forms an aperture image upon an optical device which redirects this image to a charge coupled device (CCD) camera 30. The image is converted to a map of measured reflectance data by a digitizing circuit 34 and a computer 36. This map of measured reflectance data is then compared to reference reflectance data to generate a map of the outer layer thickness profile of the wafer 24.

Abstract: An apparatus (1) that measures the thickness of a thin film layer of a wafer (24), includes a filtered white light source that forms a monochromatic light beam. The white light source includes a halogen lamp (10), a condensing lens (12), a circular aperture (14), a collimator lens (16), a narrow band filter wheel (18), and a second collimator lens (20). The monochromatic light beam generated by this filtered white light source illuminates an entire surface of the wafer (24). Prior to illumination, the wafer (24) is deformed into a reflective condenser. Thus, the monochromatic light beam that illuminates the wafer (24) is reflected off the wafer (24) and collected by an optical scheme that redirects the beam to a detector array (31) of a charge coupled device (CCD) camera (30).

Abstract: An apparatus (1) that measures the thickness of a thin film layer of a wafer (24), includes an extended light source that forms a diffuse polychromatic light beam. The extended light source includes a halogen lamp (10), a fiber optic light guide (12), a ground glass screen (19), and a condenser lens (16). The diffuse polychromatic light beam generated by this extended light source illuminates an entire surface of the wafer (24). The diffuse polychromatic light beam is reflected off the wafer (24) and passed through a spatial filter (26, 28) and a spectral filter (37, 38) so as to form a monochromatic light beam that is projected onto a detector array (31) of a charge coupled device (CCD) camera (30). The monochromatic light beam displays an interference fringe pattern image on the CCD camera detector array (31) which is the result of coherent interactions in the diffuse polychromatic light beam as it is reflected within the wafer structure (24).