Mentor Graphics Corporation

Lsi Logic Corporation

Lsi Corporation

Robert Brady Benware

Wu-Tung Cheng

Manish Sharma

Huaxing Tang

Xiaoxin Fan

Yu Jane Huang

Mark A Kassab

Jonathan James Muirhead

Avijit Dutta

Christopher W Schuermyer

Chen-Yi Chang

Robert Madge

Thai Minh Nguyen

Steven L Haehn

Cam Luong Lu

Robert Randal Klingenberg

Ritesh P Turakhia

Cary Gloor

Aspects of the invention relate to yield analysis techniques for generating root cause candidates for yield analysis. With various implementations of the invention, points of interest are first identified in a layout design. Next, regions of interest are determined for the identified points of interest. Next, one or more properties are extracted from the regions of interest. Based at least on the one or more properties, diagnosis reports of failing devices fabricated according to the layout design are analyzed to identify probable root causes.

Generating root cause candidates for yield analysis

Various aspects of the disclosed technology relate to circuit defect diagnosis based on sink cell fault models. Defect candidates are determined based on path-tracing from failing bits into the circuit design. Based on the defect candidates and one or more conventional fault models, failing test pattern simulations are performed to determine initial defect suspects. Initial defective sink cell suspects are then determined by comparing driving strengths for fan-out cells of the initial defect suspects with driving strengths for corresponding driver cells. Defective sink cell suspects may be identified in the initial defective sink cell suspects based on fault effect propagations and passing test pattern simulations.

Circuit defect diagnosis based on sink cell fault models

Yield excursions in the manufacturing process today require an expensive, long and tedious physical failure analysis process to identify the root cause. Techniques are disclosed herein for efficiently identifying the root-cause of a manufacturing yield excursion by analyzing fail data collected from the production test environment. In particular, statistical hypothesis testing is used in a novel way to analyze logic diagnosis data along with information on physical features in the design layout and reliably identify the cause of the yield excursion.

Identifying the defective layer of a yield excursion through the statistical analysis of scan diagnosis results

Aspects of the invention relate to techniques for fault diagnosis based on dynamic circuit design partitioning. According to various implementations of the invention, a sub-circuit is extracted from a circuit design based on failure information of one or more integrated circuit devices. The extraction process may comprise combining fan-in cones of failing observation points included in the failure information. The extraction process may further comprise adding fan-in cones of one or more passing observation points to the combined fan-in cones of the failing observation points. Clock information of test patterns and/or layout information of the circuit design may be extracted and used in the sub-circuit extraction process. The extracted sub-circuit may then be used for diagnosing the one or more integrated circuit devices.

Dynamic design partitioning for diagnosis

Aspects of the disclosed technology relate to techniques for determining canonical forms of layout patterns. Coordinates of vertices of geometric elements in a window of a layout design are first transformed into new coordinates of the vertices, wherein the coordinates of vertices do not comprise clipped coordinates and the transforming comprises: performing a translation on the coordinates of vertices based on differences between maximum and minimum X/Y coordinate values of the vertices. Based on sums of X/Y coordinate values of the new coordinates of the vertices, a canonical form of the geometric elements is determined. The canonical form coordinates of the vertices may then be determined and sorted. The sorted canonical form coordinates may be employed for pattern matching.

Canonical forms of layout patterns

Aspects of the invention relate to techniques for chain fault diagnosis based on dynamic circuit design partitioning. Fan-out cones for scan cells of one or more faulty scan chains of a circuit design are determined and combined to derive a forward-tracing cone. Fan-in cones for scan cells of the one or more faulty scan chains and for failing observation points of the circuit design are determined and combined to derive a backward-tracing cone. By determining intersection of the forward-tracing cone and the backward-tracing cone, a chain diagnosis sub-circuit for the test failure file is generated. Using the process, a plurality of chain diagnosis sub-circuits may be generated for a plurality of test failure files. Scan chain fault diagnosis may then be performed on the plurality of chain diagnosis sub-circuits with a plurality of computers.

Dynamic design partitioning for scan chain diagnosis

Disclosed are representative embodiments of methods, apparatus, and systems for partitioning-based Test Access Mechanisms (TAM). Test response data are captured by scan cells of a plurality scan chains in a circuit under test and are compared with test response data expected for a good CUT to generate check values. Based on the check values, partition pass/fail signals are generated by partitioning scheme generators. Each of the partitioning scheme generators is configured to generate one of the partition pass/fail signals for one of partitioning schemes. A partitioning scheme divides the scan cells into a set of non-overlapping partitions. Based on the partition pass/fail signals, a failure diagnosis process may be performed.

Test access mechanism for diagnosis based on partitioning scan chains

Aspects of the invention relate to yield analysis techniques for generating root cause distribution information. Suspect information for a plurality of failing dies is first generated using a layout-aware diagnosis method. Based on the suspect information, potential root causes for the plurality of failing dies, and suspect feature weights and total feature weights for each of the potential root causes may then be determined. Next, the probability information of observing a particular suspect that is related to a particular root cause may be extracted. Finally, an expectation-maximization analysis may be conducted for generating the root cause distribution information based on the probability information and the suspect information. Heuristic information may be used to prevent the analysis from over-fitting.

Root cause distribution determination based on layout aware scan diagnosis results

Aspects of the invention relate to techniques for fault diagnosis based on circuit design partitioning. According to various implementations of the invention, a circuit design of a failing die is first partitioned into a plurality of sub-circuits. The sub-circuits may be formed based on fan-in cones of observation points. Shared gate ratios may be used as a metric for adding fan-in cones of observation points into a sub-circuit. Based on test patterns and the sub-circuits, sub-circuit test patterns are determined. Fault diagnosis is then performed on the sub-circuits. The sub-circuit fault diagnosis comprises extracting sub-circuit failure information from the failure information for the failing die. The sub-circuit fault diagnosis may employ fault-free values for boundary gates in the sub-circuits.

Fault diagnosis based on design partitioning

Test access mechanism for diagnosis based on partitioining scan chains

A method and computer program for detecting and locating defects in integrated circuit die from stimulation of statistical outlier signatures includes receiving as input a test value of an electrical parameter measured for each of a plurality of identically designed electrical circuits, identifying one of the identically designed electrical circuits as an outlier for which the test value of the electrical parameter varies from a mean test value of the electrical parameter for the plurality of identically designed electrical circuits by at least a selected difference, monitoring the test value while subjecting a location on the outlier to a stimulus to detect a change in the test value as a function of the location, and generating as output the location for which the change in the test value is detected to identify a defect in the outlier.

Method and apparatus for detecting defects in integrated circuit die from stimulation of statistical outlier signatures

A methodology for generating scan based transition patterns (i.e., ATPG pattern generation for transition delay faults ('TDF')) wherein when either a slow-to-rise (STR) or a slow-to-fall (STF) transition fault is detected, that specific fault is removed from a fault universe as well as its companion TDF, wherein the companion fault is a fault on the same node as the detected fault but has the opposite transition. In other words, if a slow-to-rise (STR) transition fault is detected, the slow-to-rise (STR) transition fault is removed from the fault universe as well as its corresponding slow-to-fall (STF) transition fault (and vise versa). By removing companion faults as well as those which are specifically detected, pattern generation run time is reduced as well as the total pattern count for the final delay test pattern.

Method of generating test patterns to efficiently screen inline resistance delay defects in complex asics

A methodology for generating scan based transition patterns (i.e., ATPG pattern generation for transition delay faults ('TDF')) wherein when either a slow-to-rise (STR) or a slow-to-fall (STE) transition fault is detected, that specific fault is removed from a fault universe as well as its companion TDF, wherein the companion fault is a fault on the same node as the detected fault but has the opposite transition. In other words, if a slow-to-rise (STR) transition fault is detected, the slow-to-rise (STR) transition fault is removed from the fault universe as well as its corresponding slow-to-fall (STF) transition fault (and vise versa). By removing companion faults as well as those which are specifically detected, pattern generation run time is reduced as well as the total pattern count for the final delay test pattern.

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Clackamas, OR, United States of America

Robert Brady Benware