Abstract: A mechanism is provided for simultaneous optical proximity correction (OPC) and decomposition for double exposure lithography. The mechanism begins with two masks that are equal to each other and to the target. The mechanism simultaneously optimizes both masks to obtain a wafer image that both matches the target and is robust to process variations. The mechanism develops a lithographic cost function that optimizes for contour fidelity as well as robustness to variation. The mechanism minimizes the cost function using gradient descent. The gradient descent works on analytically evaluating the derivative of the cost function with respect to mask movement for both masks. It then moves the masks by a fraction of the derivative.

Abstract: A contour of a mask design for an integrated circuit is modified to compensate for systematic variations arising from non-optical effects such as stress, well proximity, rapid thermal anneal, or spacer thickness. Electrical characteristics of a simulated integrated circuit chip fabricated using the mask design are extracted and compared to design specifications, and one or more edges of the contour are adjusted to reduce the systematic variation until the electrical characteristic is within specification. The particular electrical characteristic preferably depends on which layer is to be fabricated from the mask: on-current for a polysilicon; resistance for contact; resistance and capacitance for metal; current for active; and resistance for vias. For systematic threshold voltage variation, the contour is adjusted to match a gate length which corresponds to an on-current value according to pre-calculated curves for contour current and gate length at a nominal threshold voltage of the chip.

Abstract: Disclosed is a computer implemented method and computer program product to determine metal oxide semiconductor (MOS) gate functional limitations. A simulator obtains a plurality of slices of a MOS gate, the slices each comprising at least one parameter, the parameter comprising a slice gate width and a slice gate length. The simulator determines a current for each slice based on a slice gate length of the slice to form a length-based current for each slice. The simulator determines a length-based current for the MOS gate by summing the length-based current for each slice. The simulator calculates a stress profile for each slice. The simulator determines a slice carrier mobility for each slice based on the stress profile of each slice. The simulator determines a carrier mobility-based current for each slice, based on each slice carrier mobility. The simulator determines a carrier mobility for the MOS gate based on the carrier mobility-based current for each slice.

Abstract: A mechanism is provided for harmonic mean optical proximity correction (HMOPC). A lithographic simulator in a HMOPC mechanism generates an image of a mask shape based on a target shape on a wafer thereby forming one or more lithographic contours. A cost function evaluator module determines a geometric cost function associated with the one or more lithographic contours. An edge movement module minimizes the geometric cost function thereby forming a minimized geometric cost function. The edge movement module determines a set of edge movements for each slice in a set of slices associated with the one or more lithographic contours using the minimized geometric cost function. The edge movement module moves the edges of the mask shape using the set of edge movements for each slice in the set of slices. The HMOPC mechanism then produces a clean mask shape using the set of edge movements.

Abstract: A method, computer program product, and data processing system for performing an improved optical proximity correction are disclosed, which better respect the electrical properties of the device being manufactured. A preferred embodiment of the present invention performs OPC by first dividing the perimeter of a mask region into a plurality of segments, then grouping the segments into at least two distinct groups, wherein segments in the first of these groups are adjusted in position so as to minimize edge placement error (EPE) when the photolithography using the mask is simulated. Segments in the second group are adjusted in position so as to minimize cumulative error in a dimension spanning the region, wherein the span of such dimension extends from segments in the first group to segments in the second group. Correction so obtained by this process more readily preserves the intended electrical behavior of the original device design.

Abstract: A mechanism is provided for electrical yield enhancement retargeting of photolithographic layouts. Optical proximity correction is performed on a set of target patterns in order to produce a set of optical proximity correction mask shapes. A set of lithographic contours is generated for each of the set of optical proximity correction mask shapes. A determination is made of electrical yield sensitivities for at least one shape in a set of shapes in the set of target patterns. A determination is also made as to an amount and a direction of retargeting for each of the at least one shape in the set of shapes based on the electrical yield sensitivity of the shape. A new set of target patterns with retargeted edges is generated for each shape in the at least one shape based on the amount and the direction of retargeting.

Abstract: A mechanism is provided for simultaneous photolithographic mask and target optimization (SMATO). A lithographic simulator generates an image of a mask shape on a wafer thereby forming one or more lithographic contours. A mask and target movement module analytically evaluates a direction for mask and target movement thereby forming a plurality of pairs of mask and target movements. The mask and target movement module identifies a best pair of mask and target movements from the plurality of mask and target movements that minimizes a weighted cost function. A shape adjustment module adjusts at least one of a target shape or the mask shape based on the best pair of mask and target movements.

Abstract: A test system and computer program for measuring threshold voltage variation using a device array provides accurate threshold voltage distribution values for process verification and improvement. The test system and computer program control a characterization array circuit that imposes a fixed drain-source voltage and a constant channel current at individual devices within the array. Another circuit senses the source voltage of the individual device within the array. The statistical distribution of the threshold voltage is determined directly from the source voltage distribution by offsetting each source voltage by a value determined by completely characterizing one or more devices within the array. The resulting methodology avoids the necessity of otherwise characterizing each device within the array, thus reducing measurement time dramatically.

Abstract: A method and test circuit provide measurements to aid in the understanding of time-varying threshold voltage changes such as negative bias temperature instability and positive bias temperature instability. In order to provide accurate measurements during an early stage in the threshold variation, a current generating circuit is integrated on a substrate with the device under test, which may be a device selected from among an array of devices. The current generating circuit may be a current mirror that responds to an externally-supplied current provided by a test system. A voltage source circuit may be included to hold the drain-source voltage of the transistor constant, although not required. A stress is applied prior to the measurement phase, which may include a controllable relaxation period after the stress is removed.

Abstract: A parallel array architecture for constant current electro-migration stress testing is provided. The parallel array architecture comprises a device under test (DUT) array having a plurality of DUTs coupled in parallel and a plurality of localized heating elements associated with respective ones of the DUTs in the DUT array. The architecture further comprises DUT selection logic that isolates individual DUTs within the array. Moreover, the architecture comprises current source logic that provides a reference current and controls the current through the DUTs in the DUT array such that each DUT in the DUT array has substantially a same current density, and current source enable logic for selectively enabling portions for the current source logic. Electro-migration stress testing is performed on the DUTs of the DUT array using the heating elements, the DUT selection logic, current source logic, and current source enable logic.

Abstract: Mechanism are provided for model-based retargeting of photolithographic layouts. An optical proximity correction is performed on a set of target patterns for a predetermined number of iterations until a counter value exceeds a maximum predetermined number of iterations in order to produce a set of optical proximity correction mask shapes. A set of lithographic contours is generated for each of the set of optical proximity correction mask shapes in response to the counter value exceeding the maximum predetermined number of iterations. A normalized image log slope (NILS) extraction is performed on the set of target shapes and use the set of lithographic contours to produce NILS values. The set of target patterns is modified based on the NILS values in response to the NILS values failing to be within a predetermined limit. The steps are repeated until the NILS values are within the predetermined limit.

Abstract: A configurable PSRO measurement circuit is used to measure the frequency dependent capacitance of a target through silicon via (TSV) or other conductive structure. Measurements of the target structure are aided by using adjustable resistors and a de-embedding structure to measure the effects of parasitic capacitance, CPAR. Current is measured to both the device under test (DUT) and the de-embedding structure. From these measurements, the frequency dependent capacitance of the DUT is calculated.

Abstract: System and method for obtaining statistics in a fast and simplified manner at the wafer level while using wafer-level test equipment. The system and method performs a parallel stress of all of the DUTs on a given chip to keep the stress time short, and then allows each DUT on that chip to be tested individually while keeping the other DUTs on that chip under stress to avoid any relaxation. In one application, the obtained statistics enable analysis of Negative Temperature Bias Instability (NTBI) phenomena of transistor devices. Although obtaining statistics may be more crucial for NBTI because of its known behavior as the device narrows, the structure and methodology, with minor appropriate adjustments, could be used for stressing multiple DUTs for many technology reliability mechanisms.

Abstract: A unified test structure having a large number of electronic devices under test is used to characterize both capacitance-voltage parameters (C-V) and current-voltage parameters (I-V) of the devices. The devices are arranged in an array of columns and rows, and selected by control logic which gates input/output pins that act variously as current sources, sinks, clamps, measurement ports and sense lines. The capacitance-voltage parameter is measured by taking baseline and excited current measurements for different excitation voltage frequencies, calculating current differences between the baseline and excited current measurements, and generating a linear relationship between the current differences and the different frequencies. The capacitance is then derived by dividing a slope of a line representing the linear relationship by the excitation voltage. Different electronic devices may be so tested, including transistors and interconnect structures.

Abstract: A test circuit for fast determination of device capacitance variation statistics provides a mechanism for determining process variation and parameter statistics using low computing power and readily available test equipment. A test array having individually selectable devices is stimulated under computer control to select each of the devices sequentially. A test output from the array provides a current or voltage that dependent on a particular device parameter. The sequential selection of the devices produces a voltage or current waveform, characteristics of which are measured using a digital multi-meter that is interfaced to the computer. The rms value of the current or voltage at the test output is an indication of the standard deviation of the parameter variation and the DC value of the current or voltage is an indication of the mean value of the parameter.

Abstract: According to a method of simulation data processing, a difference is determined between a simulated value of a characteristic for a simulated integrated circuit device and a corresponding empirical value of the characteristic for a fabricated integrated circuit device. A data structure containing a simulation model of the fabricated integrated circuit device is accessed, where the data structure includes a plurality of entries each accessed via a unique index and an index used to access the data structure is offset in accordance with the difference between the simulated value and the empirical value. Operation of the simulated integrated circuit device is then simulated utilizing a value obtained from one of the plurality of entries of the data structure. Results of the simulation are stored in a data storage medium.

Abstract: In accordance with one embodiment, a plurality of empirical measurements of a fabricated integrated circuit including a fabricated transistor having multiple terminals is received. The plurality of empirical measurements each include an empirical terminal current set and an empirical terminal voltage set for the terminals of the fabricated transistor. A mathematical simulation model of a simulated transistor is also received. Utilizing the mathematical simulation model, an intermediate data set is calculated by determining, for each of a plurality of different terminal voltage sets, a simulated terminal current set and a simulated terminal charge set. A modeling tool processes the intermediate data set to obtain a time domain simulation model of the fabricated transistor that, for each of the plurality of empirical measurements, provides a simulated terminal charge set. The time domain simulation model is stored in a computer-readable data storage medium.

Abstract: Disclosed is a computer implemented method and computer program product to determine metal oxide semiconductor (MOS) gate functional limitations. A simulator obtains a plurality of slices of a MOS gate, the slices each comprising at least one parameter, the parameter comprising a slice gate width and a slice gate length. The simulator determines a current for each slice based on a slice gate length of the slice to form a length-based current for each slice. The simulator determines a length-based current for the MOS gate by summing the length-based current for each slice. The simulator calculates a stress profile for each slice. The simulator determines a slice carrier mobility for each slice based on the stress profile of each slice. The simulator determines a carrier mobility-based current for each slice, based on each slice carrier mobility. The simulator determines a carrier mobility for the MOS gate based on the carrier mobility-based current for each slice.

Abstract: A unified test structure having a large number of electronic devices under test is used to characterize both capacitance-voltage parameters (C-V) and current-voltage parameters (I-V) of the devices. The devices are arranged in an array of columns and rows, and selected by control logic which gates input/output pins that act variously as current sources, sinks, clamps, measurement ports and sense lines. The capacitance-voltage parameter is measured by taking baseline and excited current measurements for different excitation voltage frequencies, calculating current differences between the baseline and excited current measurements, and generating a linear relationship between the current differences and the different frequencies. The capacitance is then derived by dividing a slope of a line representing the linear relationship by the excitation voltage. Different electronic devices may be so tested, including transistors and interconnect structures.

Abstract: A unified test structure having a large number of electronic devices under test is used to characterize both capacitance-voltage parameters (C-V) and current-voltage parameters (I-V) of the devices. The devices are arranged in an array of columns and rows, and selected by control logic which gates input/output pins that act variously as current sources, sinks, clamps, measurement ports and sense lines. The capacitance-voltage parameter is measured by taking baseline and excited current measurements for different excitation voltage frequencies, calculating current differences between the baseline and excited current measurements, and generating a linear relationship between the current differences and the different frequencies. The capacitance is then derived by dividing a slope of a line representing the linear relationship by the excitation voltage. Different electronic devices may be so tested, including transistors and interconnect structures.