Abstract: A method and system for performing reflectance measurements of a sample using radiation having UV frequency components (preferably in a broad UV band) and visible frequency components (preferably in a broad band). Preferably, two detectors simultaneously receive a sample beam reflected from the sample surface. One detector generates a signal indicative of the sample beam components in the UV band and the other detector generates a signal indicative of the sample beam components in the visible band. By processing these two signals, the invention enables accurate measurement of the thickness of a very thin film on the sample. Preferably, the system determines a single effective wavelength for the UV radiation incident on the first detector and a single effective wavelength for the visible radiation incident on the second detector. Embodiments of the system can also measure reflectance spectra and refractive indices, and can determine lithographic exposure times.

Abstract: A method and apparatus for imaging a substrate (such as silicon or silicon dioxide) beneath and between a dense array of strips (such as photoresist strips composed of dielectric or other material) using a polarizing optical microscope. In preferred embodiments, the apparatus of the invention includes a polarizer for polarizing optical illuminating radiation, an analyzer for receiving polarized radiation reflected from the sample, and a variable retarder whose retardation characteristic can be controlled to enhance the light signal transmitted through the analyzer from the substrate in a region of interest of the sample. The variable retarder can be a fixedly mounted retarder whose birefringence is variable in response to a control signal, or a rotatably mounted retarder plate having fixed birefringence which is mechanically rotatable to control the orientation of its optical axis.

Abstract: The resistivity of the surface of a semiconductor wafer is measured at different temperatures to determine the resistivity as a function of temperature. The temperature of the semiconductor wafer is varied by a heater in thermal contact with the semiconductor wafer, and the temperature is measured by a temperature sensor in thermal contact with the semiconductor. The heater is controlled by a control unit which adjusts the amount of heat provided by the heater, thereby controlling the temperature at which a measurement from a four-point resistivity probe is taken.

Abstract: A data analysis computer system stores measurement data obtained from a multiplicity of distinct predefined processes. The system can store definitions for many data analysis charts, each of which depicts stored measurement data for a specified process. Further, chart groups can be defined. Each chart group comprises a set of data analysis charts that grouped together for convenient access. Charts are displayed by either (1) selecting a defined chart, or (2) by selecting a chart group and then selecting one or more charts from the selected group for, and then simultaneously displaying the selected data analysis charts. A data display gallery feature divides the computer system's display into a two dimensional array of cells, and assigns cell definitions to at least a subset of the cells. Each cell definition consists of either a set of measurement data which can be displayed as a unit, or a mathematical combination of a plurality of specified sets of measurement data.

Abstract: An improved real-time confocal scanning microscope, and an improved perforated disk for use in such microscope. A preferred embodiment of the inventive microscope includes a polarizing beamsplitting cube and a rotatable Nipkow disk perforted with a hexagonal hole pattern. The disk is preferably mounted so that the scan lines produced as the disk rotates will cross both the sample feature to be imaged and the sensor array in the system's video camera at an angle substantially equal to 45 degrees. This disk orientation ensures that brightness variations caused by a non-uniform scan will not affect the measurements. Rotation of the disk is preferably synchronized with the camera frame rate to prevent any scan errors from causing random (frame to frame) variations in the camera output. The polarizing beamsplitting cube consists of two triangular prisms connected (i.e., cemented) together by a dielectric film.

Abstract: A system and method for computer control of machine processes. The system and method provide a set of predefined data management or data analysis tasks which an operator of the system can use when using the system to run a selected process.Measurement data structures for storing data measured during the running of processes, and related data, for a multiplicity of processes are defined and stored. Data is added to these data structures each time a process is run, and this data is automatically accessed when the operator requests data analysis on the data collected during previous uses of a selected process.Access to measurement data for detailed data management tasks is provided graphically through the use of trend charts and statistical quality control charts. These charts depict trends in the measurement data for selected processes. By pointing at any data point in the chart, the user can access the corresponding record of data for detailed data analysis or for use in a data management task.

Abstract: A method of selecting items from a hierarchy of items and then performing a selected task on the selected set of items. An engineering set up control program includes a procedure for denoting processes, groups of processes, and subgroups of processes which are available for use by operators of the system. The processes, groups and subgroups are visually presented in a three level menu. Subgroups and groups of processes can be selected using the three level menu, and then operated on as a group.

Abstract: An autofocusing system for a microscope is disclosed. An autofocus target is placed between a colliminating lens and a relay lens of the microscope. The autofocus target contains a pattern of dark areas which are projected onto a specimen and reflected into a CCD camera array. The focus of the microscope is adjusted such that the variation in intensity of light through the pattern is maximized.

Abstract: A semiconductor wafer handling apparatus for automated movement of semiconductor wafers between wafer cassette trays and wafer test systems is provided. The apparatus includes a platform for carrying at least one semiconductor wafer cassette tray, a wafer alignment device carried by the platform for aligning a semiconductor wafer in a predetermined test position and a wafer transfer device associated with the platform and the wafer alignment device for transferring the wafer between the cassette tray, the alignment device and the test system. The wafer transfer device is operational in the same plane relative to the platform and capable of extending, retracting and rotating in the plane.

Abstract: A system and method for computer control of machine processes. The operator of the system selects and specifies process control parameters through the use of a three level dynamic menu. The first level of the menu is used to select a group of process parameters. The second and third menus together have the visual appearance of a set of index cards, the second menu forming tabs on the index cards, and the third menu comprising the set of process parameters listed on each index card. Each process parameter has a preassigned entry status: operator unalterable, operator alterable, forced operator entry, or single time forced entry (value must be entered only once when the process is run several times). The selected process cannot be run until values have been entered for all parameters having an entry status of forced operator entry or single time forced entry. Edit field parameters limit the operator's options to a predefined set of parameter values.

Abstract: A process control interface includes a multi-level dynamic menu for selecting processes from a set of processes that are organized into groups and subgroups. An engineering set up control program enables an engineer to denote which of these groups, subgroups and processes are available for selection by an operator using the process control interface. Only those groups, subgroups and processes which are available for selection are displayed in the dynamic menu. The set of processes defined by the engineering set up control program can be stored on individual operator-related disks so that each operator has access to a distinct set of available processes. Process subgroups and groups can be duplicated by the engineering setup control program to facilitate the setting up of new control processes.

Abstract: A method of controlling a process using a programmed digital computer with a set of process control programs. An operator control program allows the user to select and run a specified process and to collect measurement data while the selected process is run. A data analysis program enables interactive computer controlled data analysis, including displaying a trand chart depicting a sequence of data points, each data point representing at least a portion of the measurement data collected and stored while running a selected process. A selectably positionable pointer is displayed on the trend chart for pointing at an individual data point so that the user can select and perform a predefined task on the measurement data stored in the data structure corresponding to the data point being pointed at by said selectably positionable pointer.

Abstract: A system for ascertaining the thickness of thin films, especially on semiconductor substrates, comprising a light source, a randomized bifurcated fiber optic bundle, a pentamirror, a rapid scanning monochromator with a rotating grating, a photodetector, and A/D converter, an interface and a data reduction computer. The randomized bifurcated fiber optic bundle via the pentamirror directs light to and receives reflected light from a surface of the thin film, the reflected light passes through the bifurcated bundle to the monochromator and to the photodetector whose output is read by the A/D converter. A timing control circuit is provided which has an input from an encoder coupled to the motor rotating the grating and clock and trigger outputs coupled to the A/D converter so that the A/D converter consistently samples the analog signal representative of the same portions of the reflected visible spectra returned from the thin film under test.

Abstract: An automatic system for performing sheet resistivity testing on surface layers of semiconductor wafers, including a wafer handling stage having a platform for carrying a semiconductor wafer, and an arrangement for mounting the platform for rotation about a central axis and for translation of the platform orthogonal to a major surface thereof. A platform drive translates the platform between a wafer test position and a wafer load position, and a stage drive rotates the platform to accurately located angular test positions. A probe handling arrangement includes a carriage for carrying a test probe parallel to the major surface of a wafer on the platform and a carriage drive translates the carriage between a parked position in which a test prove thereon is positioned adjacent and clear of the platform and accurately located test positions along a radius of the platform. The carriage carries a resistivity test probe which includes test probe element for contacting the surface of a semiconductor wafer.

Abstract: An automatic sheet resistance mapping system for semiconductor wafers which has the capability of taking high accuracy, multiple test readings in both contour scan and diameter scan modes. A rotatable wafer stage carries a semiconductor wafer thereon with the center of the wafer positioned substantially at the axis of rotation of the wafer stage. A probe head assembly, including a linear array of at least four equally spaced probe tips projecting from one surface of the assembly is mounted facing the wafer stage on an arrangement for moving the probe tips alternately into and out of contact with the surface of a wafer carried thereon. Positioning arrangements are provided for rotating the wafer stage to accurately registered angular test positions and for producing translation between the wafer stage and the probe head assembly to position the array of probe tips at accurately registered radial test positions relative to the center of the wafer.

Abstract: A system and method for computer control of machine processes, including a dynamic menu feature used in the selection of processes and the definition and selection of operating parameters used by a process control program to direct the performance of the process by the machine.Data structures for a multiplicity of processes are defined and stored. Values stored in the data structures indicate which processes are available for use and the process control program associated with each process. Furthermore, for each parameter of each process a data structure contains an indicia of whether the parameter is a forced entry parameter (which must be given a value before the process is run), a may change parameter (with a default value that may be changed when the process is run), or a locked parameter which has a fixed value.