Abstract: A laser beam is used to probe an integrated circuit device under test. A single laser provides a single laser pulse which is divided into two pulses, both of which are incident upon the device under test. After the two pulses interact with the device under test, the two pulses are separated and detected by two photo detectors. The electrical signals output by the photo detectors are then subtracted, which cancels out any common mode noise induced on both pulses including noise due to mechanical vibration of the device under test and also any noise from the laser. The difference signal can be used to reproduce a time varying signal in the device under test.

Abstract: Methods of inspecting a microstructure comprise: applying charged particles to the wafer to negatively charge up the wafer over a region having contact or via holes, scanning a charged-particle beam over the region while detecting secondary particles so as to produce a detector signal, determining from the detector signal an apparent dimension of a contact hole, and comparing the apparent dimension of the contact hole with reference information to identify a defect. The reference information can be a conventional voltage-contrast image or can be design data indicating expected physical size of the contact hole and expected electrical connectivity of material within or beneath the contact hole. The wafer can be charged up by directing a flood of electrons toward a surface of the wafer and/or by controlling potential of an energy filter so as to direct secondary electrons back to the wafer while directing a charged-particle beam at the wafer.

Abstract: Methods are provided for exposing a selected feature of an IC device, such as a selected conductor, from the back side of the substrate without disturbing adjacent features of the device, such as active regions. One such method comprises: (a) determining a region of the IC device in which the selected feature is located; (b) acquiring from the back side of the substrate an IR optical microscope image of the region; (c) aligning the IR optical microscope image with a coordinate system of a milling system; and (d) using structures visible in the IR optical microscope image as a guide, operating the milling system to expose the selected feature from the back side of the IC device without disturbing adjacent features.

Abstract: The shape of a sample is determined with a scanning electron microscope ("SEM") by using electron emission from a surface to measure its slope. A surface of a sample is placed in the SEM's electron beam for several known angles, and respective measurements of the electron emission are obtained. A relationship between surface angle and electron emission is derived for the sample from the measurements. Then, as the electron beam is scanned along the surface to measure electron emission, this derived relationship is used to obtain the slope at each scanning point.

Abstract: In a tester for testing circuits, apparatus and methods for acquiring waveform data from a circuit under test. While a test program is being run by the tester, waveform acquisition strobe events are generated for application to a terminal of a circuit under test. A measurement circuit receives the waveform acquisition strobe events and applies each strobe event to the terminal of the circuit and generates result signals representing the result of applying the strobe events to the terminal. A capture memory receives and stores result signals generated by the measurement circuit.

Abstract: A method for detecting electrical defects in a semiconductor wafer, includes the steps of: a) applying charge to the wafer such that electrically isolated structures are raised to a voltage relative to electrically grounded structures; b) obtaining voltage contrast data for at least a portion of the wafer containing such structures using an electron beam; and c) analyzing the voltage contrast data to detect structures at voltages different from predetermined voltages for such structures. Voltage contrast data can take one of a number of forms. In a simple form, data for a number of positions on a line scan of an electron beam can be taken and displayed or stored as a series of voltage levels and scan positions. Alternatively, the data from a series of scans can be displayed as a voltage contrast image.

Abstract: Apparatus and method for measuring the time interval between a first event and a second event in a tester system. First and second time measurement circuits independently receive respective first and second events. The time measurement circuits each includes a coarse counter clocked by the master clock. The first coarse counter is activated by an initial event, and the first coarse counter stops counting upon activation of the first event. The second coarse counter is also activated by the initial event, and the second coarse counter stops counting upon activation of the second event. A first fine counter clocked by the master clock produces a count value representing the time interval between the first event and a first leading edge of the master clock. A second fine counter clocked by the master clock produces a count value representing the time interval between the second event and a second leading edge of the master clock.

Abstract: This invention pertains to the embedding of a information storage device within, or attached to, the carriers used to transport work in progress from step to step in the semiconductor manufacturing process. The carrier can be a tray having sites for several semiconductor dies, tubes for carrying several dies together, lead frames, wafer cassettes or individual die sockets. The information storage device can be formed integrally with the carrier or formed separately and attached or secured to the carrier.

Abstract: A system for transactional taxation includes a secure stored data device, such as a smart card, having means for storing purchaser-specific data, an interface device for communicating with the secure stored data device and means for determining a tax rate on a purchase using the purchaser-specific data.

Abstract: A system for tracking continuing education includes a secure stored data device, such as a smart card, storing practitioner-specific data, and a read/write device for communicating with the secure stored data device and for writing course attendance information for the practitioner to the secure stored data device. A professional education server initiates the secure stored data device and the read/write device, accepts data from the secure stored data device and the read/write device, verifies compliance with education requirements and verifies consistency in the data sets.

Abstract: A system for testing an automotive engine management system (EMS), comprises (a) means for generating a series of EMS input signals which are equivalent to input signals generated by an automobile; (b) means for applying the EMS input signals to the EMS in a manner which simulates that of the inputs from an automobile; (c) a series of loads connected to outputs from the EMS, the loads being equivalent to the loads imposed by systems within an automobile under the control of the EMS; (d) sensors for measuring the EMS outputs; and (e) means for coordinating, in real time, application of the EMS inputs and measurement of the EMS outputs.

Abstract: A algorithmic pattern generator (APG) in a memory tester having a programmable first ALU generating an first value on a first output data path; a programmable Z ALU generating a Z value on an Z output data path; and a programmable second ALU having terminals to receive the Z value from the Z ALU and a circuit to insert bits of the received Z value into low order bits of a second value before outputting the second value on a second output data path. In embodiments, the first value and the second value are generated to define a location in an array of memory cells of a memory under test; and the second value contains low order bits corresponding to address bits that are incremented internally by the memory under test in a burst mode of operation.

Abstract: A method of processing a semiconductor device comprises: applying a focused ion beam to a structure of a semiconductor device to be processed; producing a live detector signal by detecting secondary electrons emitted as the focused ion beam is applied to the structure; comparing the live detector signal with a reference trace having a region indicative of an expected material boundary and a stop marker within said region; and terminating or altering a FIB operation when the live detector signal exhibits a characteristic corresponding to said region of the reference trace.

Abstract: Apparatus and methods providing pattern chaining and looping in a circuit tester. The tester has a pattern data memory for storing multiple patterns and for storing a pattern chaining definition. Each pattern has pattern data for one or more test vectors. The pattern chaining definition specifies (i) a sequential order for the patterns and (ii) a location in the pattern data memory of each of the patterns. When the tester executes a functional test, the pattern chaining definition is read from the pattern data memory and used to locate each of the patterns, and the pattern data of each pattern is read to provide a test vector for each test period of the functional test. In another aspect, both a pattern program including one or more test vectors and a loop definition are stored in the pattern data memory. The pattern program defines an ordering for the test vectors, and the loop definition specifies a loop of test vectors.

Abstract: Sampling a waveform in an IC device to which a repeating test pattern is applied, includes the steps of: a) defining a portion of the test signal containing a feature of interest; b) applying a sampling signal to an AFM device adjacent a surface of the IC device at a predetermined point during the portion for a series of consecutive repetitions of the test signal pattern, the sampling signal having substantially shorter duration than the feature of interest; c) measuring deflection of a cantilever in the AFM device on application of the sampling signal; and d) determining the voltage at the predetermined point from the measured deflection of the cantilever. The steps can be applied at several points in the portion of interest and the measurements integrated and displayed.

Abstract: The head of a pick and place system for removing IC parts from a tray and inserting them into a burn-in board (BIB) includes one or more sensors which detect light reflected from a part picked up from a tray and outputs a signal which can be analyzed to determine if the part is improperly seated in the head (misprecised) or improperly inserted into the socket of a BIB (misinserted).

Abstract: An optical system for a particle beam device such as an electron microscope, e-beam device or FIB device, including a particle beam column having an optical axis along which a beam of particles is projected and an apertured plate positioned in the column having an aperture which is coaxial with the optical axis, the plate being moveable in a direction which is parallel to the optical axis.

Abstract: A method simulating the filtering of a current pulse in a series of pulses. The method includes receiving a series of n+1 consecutive pulse addresses, including a pulse address for the current pulse as the last in the series of n+1, each pulse address being in a range of m values; storing the n pulses addresses prior to the current pulse address; building a composite address from the current pulse address and the prior n pulse addresses and applying the composite address to read a pulse shape from a memory of at least m.sup.n+1 pulse shapes. Also, apparatus issuing high speed pulses of programmable length.

Abstract: A system for testing circuits includes a tester having a pattern memory for storing test vectors; an object database to store a persistent vector pattern object including a pattern of test vectors; and an object-oriented database management server process. The server process is a computer program configured to run on a server processor in communication with the object database. The server process and the tester operate together to obtain the vector pattern object from the object database and to load the pattern of test vectors from the object into the pattern memory. The tester can have a processor to run a database client process. The vector pattern object can include member functions to modify the vector pattern.

Abstract: A probe beam is used to sample the waveform on an IC device under test (DUT) during each cycle of a test pattern applied to the DUT. A reference laser beam is also used to sample the DUT. For each cycle of the test pattern, the reference and probe beams sample the DUT at the same physical location, but at displaced times with respect to each other. Each reference measurement is made at a fixed time relative to the test pattern while the probe measurements are scanned through the test-pattern time portion of interest, in the manner normal to equivalent time sampling, to reconstruct the waveform. For each test cycle, the ratio of these two measurements is taken. The fluctuations of these ratios due to noise is greatly reduced as compared to fluctuations of the probe measurements taken alone. Thus, a smaller number of averages is required to reconstruct the waveform.