| 主权项 |
1. An optical measurement system for measuring high aspect ratio through silicon structures, each high aspect ratio through silicon structure defining a top surface and a bottom surface, with the structures having a variety of sizes etched on an etched side of silicon wafers, said system comprising:
A) a light source and optical components providing a measurement beam which is nearly collimated and which is adjustable to provide a spot size of the same order of magnitude as the size of the high aspect ratio silicon structure, B) an XYZ stage and a system controller adapted to direct illumination from the light source toward the etched side of the wafer so as to illuminate with a beam spot the top and bottom of individual high aspect ratio through silicon structures, C) a camera for imaging the high aspect ratio through silicon structures, D) a spectrometer for determining depths of individual high aspect ratio silicon structures based on interference between light reflected from the top surface and the bottom surface of the through individual high aspect ratio through silicon structures, E) a beam splitter adapted to direct a portion of the light reflected from the wafer to the camera for imaging purposes and light reflected from the top and bottom surfaces of the high aspect ratio through silicon structure to the spectrometer, and F) a computer processor for determining depth of the individual high aspect ratio through silicon structures from optical information produced by said camera and said spectrometer, and G) a grating and a linear CCD array: wherein the spot size is approximated by the following expression:
Spot Size(y)=(F1/F2)*(Sy)Spot Size(x)=(F1/F2)*(Px) where F1 is the focal length of the objective, F2 is the focal length of the spectrometer lens, Sy is the size of the slit opening, and Px is the size of the pinhole diameter. |
