Abstract: A metrology/inspection system moves the imaging and/or measuring equipment of the system relative to a wafer. Accordingly, measurement or inspection of the wafer does not require that the wafer be mounted on a precision stage. This allows the wafer to be at rest on any structure native in a processing apparatus when the system measures or inspects the wafer. Accordingly, measurement does not require removing the wafer from the processing apparatus and does not delay processing since the wafer can be measured, for example, during a required cool down period of device fabrication process. Alignment of an optical system includes pre-alignment base on edge detection using the optical system and more precise alignment using image recognition. An R-? stage can position the optical system at inspection areas on the wafer. Image rotation can provide a fixed orientation for all images at the various inspection areas and can maintain the fixed orientation when moving from one inspection area to the next.

Abstract: A metrology system includes a positioning system that produces linear and rotational motion between an imaging system and the wafer. The imaging system produces signals representing the image of the wafer in the field of view of the imaging system. A control system receives and processes the image signals, and generates corrected signals that compensate for rotational movement between the imaging system and the wafer. In response to the corrected signals, a monitor displays an image with the orientation of features on the wafer within the field of view unaffected by the rotational movement.

Abstract: An actuated edge grip chuck includes tabs with raised portions that press against the side of a substrate as opposed clamping on the top or bottom surfaces. The edge grip chuck includes a solid-state actuator to move a moveable tab into an open position. The solid-state actuator may be, e.g., a piezoelectric actuator or a shape memory alloy. The tab may be biased into the closed position such that when a substrate is held by the edge by the moveable tab and one or more fixed tabs. If desired, more than one moveable tab may be used.

Abstract: An encoder includes a layer on the scale that has a thickness that varies as a function of position along the length of the scale. The position of the sensor head with respect to the scale may be determined by measuring the thickness of the layer or index of refraction, e.g., using a reflectometer, and converting the thickness to the lateral position. In one embodiment, the thickness of the layer is used to provide a rough position of the sensor head with respect to the scale and an alignment target that includes periodic patterns on both the sensor head and scale is used to provide a refined position.

Abstract: A polar coordinate stage that may be used in a chamber includes a rotating chuck that moves in a linear direction and has the motors that drive the motion of the chuck outside the chamber. The stage can include a linkage of arms to support and drive the linear motion of the chuck. The chuck is coupled to a horizontal rail such that rotational motion of a first arm is translated into precise linear motion of the chuck along the horizontal rail through a second arm. In addition, a system of pulleys within the arms translates rotational (or linear) motion through the arms and rotates the chuck. Vertical motion may be provided by an actuator between the second arm and the chuck or by a motor under the stage. Because of the compact nature of the stage, it can be easily placed within a chamber.

Abstract: A stage used, e.g., in semiconductor fabrication, includes a two substrate buffer station and a movable chuck. The buffer station, in one embodiment is fixed, i.e., non-movable relative to the stage. In another embodiment, the support elements of the buffer station may move in unison vertically or horizontally. In another embodiment, a pair of the support elements horizontally moves toward another pair of support elements to reduce the necessary horizontal motion of the chuck. For example, an unprocessed substrate is loaded onto the top supporting elements of the buffer station, while processed substrates are unloaded from the bottom supporting element of the buffer station. The movable chuck is used to remove the unprocessed substrates from the buffer station and to place the processed substrates on the buffer station.

Abstract: A prealigner includes a light source and light detector that detects the position of the periphery of a substrate as a rotary chuck rotates the substrate. The prealigner includes a processor that receives and records the peripheral position of the substrate relative to the angular position of the substrate. The prealigner determines the center of the substrate by fitting a curve to the recorded data set, after eliminating any spikes in the data, e.g., caused by the notch or parts of the chuck. The center may then be easily and accurately determined using the amplitude and phase of the fitted curve. The position of the notch is determined by fitting a curve to the data set for the notch and determining the derivative of the curve. The mid-point of the notch and the offset error of the apex of the notch from the mid-point are calculated based on the derivative.

Abstract: A compact stage includes a rotary driver and a vertical linear driver that are in the same horizontal plane, which advantageously reduces the height of the device. The stage may include a rotating shaft to which a chuck is mounted. A rotary drive, which may be an annular rotary drive, is coupled to and rotates the rotating shaft. A linear drive is also coupled to the rotating shaft and in one embodiment extends through the center of the annular rotary drive. The linear drive moves the rotating shaft along a vertical axis. The linear drive may be, e.g., a voice coil motor that uses a spring to bias the rotating shaft along the vertical axis.

Abstract: A method for controlling a polar coordinate stage moves an object relative to an imaging system. While moving the object, the image of the object is rotated to compensate for rotation of the object. Accordingly, the orientations of features in the image are preserved, and removal of apparent rotation in the image reduces confusion an operator experiences while directing movement of the object. The angular velocity of the motion of the object is controlled so that image shift speed is independent of the radial position of the point being viewed. Use of a polar stage, reduces the required foot print for a stage and facilitates prealignment. In particular, an edge detector measures the position of the edge of the object while the polar coordinate stage rotates the object. A prealignment process determines the position and orientation of the object from the measured edge positions.

Abstract: A highly compact reflectometer system (10) for obtaining reflectance data and images from a sample (18). The reflectometer includes a light source (20) for generating a beam (Bi), a beam splitter (44) for transmitting a portion of the beam toward the sample, a lens (52) for focusing the transmitted light onto the sample, a video camera (104) for viewing a field of view (56) created by the light focused on the sample, and a spectrometer (86) for detecting and analyzing the spectrum of the light reflected from the sample. The reflectometer preferably includes a number of fold mirrors (FM1-FM6) which make the reflectometer highly compact.