Lsi Logic Corporation

Lsi Corporation

Robert Madge

Kevin Cota

Bruce Joseph Whitefield

Emery O Sugasawara

James McNames

Manu Rehani

W Robert Daasch

Daniel R Bockelman

Robert Brady Benware

David A Abercrombie

Cary Gloor

Vijayashanker Rajagopalan

A method and system of selectively identifying at risk die based on location within the reticle. Reticle and stepping information is stored in a database. All reticle shots in a wafer and in a lot are overlaid on top of each other. The reticle and stepping information is used to calculate pass/fail or specific bin yield of reticle fields. It is determined if the yield of some reticle locations is below a statistical measure by a pre-determined threshold, and if so, all the die in that location are downgraded. The statistical value to compare against does not have to be based on the reticle alone. It can be a wafer of lot level statistic. The process can be applied at a lot or wafer level, or both.

Method to selectively identify at risk die based on location within the reticle

A method for a modified binary search includes steps of: selecting a parameter having a distribution of values, selecting a probability density function representative of the distribution of values of the selected parameter, defining a substantially equal probability weighted binary test interval from the probability density function for each of a selected number of test intervals over a selected test range, translating the weighted binary test intervals to obtain a highest resolution at a target point of the selected parameter, and skewing the translated and weighted binary test intervals by a selected scaling function to generate a modified binary test interval for each of the selected number of test intervals over the selected test range.

Modified binary search for optimizing efficiency of data collection time

A method of testing integrated circuits. Each of the integrated circuits is tested with a first test at a first level of testing at a preceding testing step in a fabrication cycle of the integrated circuits to produce first test results associated with a first characteristic of the integrated circuits. The first test results are recorded with associated integrated circuit identification information. The integrated circuits are logically subdivided into bins based at least in part on the associated integrated circuit identification information. A defectivity value is calculated for each bin of subdivided integrated circuits based at least in part on the first test results recorded with the associated integrated circuit identification information. The integrated circuits within each of the bins are tested with a second test at a second level of testing at a succeeding testing step in the fabrication cycle of the integrated circuits to produce second test results associated with a second characteristic of the integrated circuits. The second characteristic is related to the first characteristic and the second level of testing is varied from bin to bin based at least in part on the defectivity value for the bin being tested.

Adaptive defect based testing

A method of detecting spatially correlated variations that may be used for detecting statistical outliers in a production lot of integrated circuits to increase the average service life of the production lot includes measuring a selected parameter of each of a plurality of electronic circuits replicated on a common surface; calculating a difference between a value of the selected parameter at a target location and a value of the selected parameter an identical relative location with respect to the target location for each of the plurality of electronic circuits to generate a distribution of differences; calculating an absolute value of the distribution of differences; and calculating an average of the absolute value of the distribution of differences to generate a representative value for the residual for the identical relative location.

Method of detecting spatially correlated variations in a parameter of an integrated circuit die

A method of inspecting a subject integrated circuit. A set of historical integrated circuits is inspected to detect defects and produce historical data. Features of the historical integrated circuits that have an occurrence of defects that is greater than a given limit are designated as high risk features, based on the historical data. Locations of the high risk features are identified on the subject integrated circuit. The locations of the high risk features are input into an inspection tool, and the locations of the high risk features on the integrated circuit are inspected to at least one of detect defects and measure critical dimensions, and produce subject data.

Feature targeted inspection

A method for adaptively providing parametric limits to identify defective die quantizes the die into a plurality of groups according to statistical distributions, such as intrinsic speed in one embodiment. For each quantization level, an intrinsic distribution of the parameter is derived. Adaptive screening limits are then set as a function of the intrinsic distribution. Dies are then screened according to their parametric values with respect to the adaptive limits.

Adaptive off tester screening method based on intrinsic die parametric measurements

A method for testing integrated circuits, where a predetermined set of input vectors is introduced as test input into the integrated circuits. The output from the integrated circuits in response to the predetermined set of input vectors is sensed, and the output from the integrated circuits is recorded in a wafer map, referenced by position designations. The recorded output for the integrated circuits is mathematically manipulated, and the recorded output for each of the integrated circuits is individually compared to the mathematically manipulated recorded output for the integrated circuits. Graded integrated circuits that have output that differs from the mathematically manipulated recorded output for the integrated circuits by more than a given amount are identified, and a classification is recorded in the wafer map for the graded integrated circuits, referenced by the position designations for the graded integrated circuits.

Statistical decision system

A method of testing an integrated circuit. A first subset of test parameters is selected from a full set of test parameters designed to characterize given properties of the integrated circuit. A first subset of devices in the integrated circuit is tested with the first subset of test parameters, using different input levels to determine an acceptable low input level and an acceptable high input level for the first subset of test parameters on the first subset of devices. At least a second subset of devices in the integrated circuit is tested, where the second subset of devices is greater in number than the first subset of devices. The test is accomplished with at least a second subset of test parameters using the acceptable low input level and the acceptable high input level, to determine whether the integrated circuit functions properly at the acceptable low input level and the acceptable high input level. The integrated circuit is selectively binned based upon the determination of whether the integrated circuit functions properly at the acceptable low input level and the acceptable high input level.

Feed forward testing

A method for identifying an integrated circuit having a latent defect. Test data corresponding to a set of integrated circuits is obtained, where the set of integrated circuits was processed on a single substrate. A subject integrated circuit is selected for analysis from within the set. A subset of integrated circuits is identified from within the set, where the subset includes integrated circuits that were located in close proximity on the substrate to the subject integrated circuit. The test data for the subset is analyzed to determine a defect parameter for the subset. The defect parameter for the subset is compared to a threshold. The subject integrated circuit is classified as having a latent defect when the defect parameter for the subset violates the threshold, and the subject integrated circuit is classified as not having a latent defect when the defect parameter for the subset does not violate the threshold.

Latent defect classification system

An apparatus for constructing a number of integrated circuits from a single substrate is provided by the present invention. A number of integrated circuits are constructed on the single substrate. The individual integrated circuits are then separated by cutting the substrate with a dicing saw. A vacuum chuck is used to grasp the individual integrated circuits while a back grinding process is performed on the individual circuits to polish the circuits to a predetermined thickness. The integrated circuits are then placed into integrated circuit packages. By performing the back grinding process after the substrate has been divided into the separate individual circuits, the present invention eliminates the need to back grind portions of the substrate that are not further used, and tends to eliminate handling of the fragile thinned substrate.

Die attach back grinding

A method of tracking information associated with an integrated circuit on a substrate after it has been diced. A set of parameters is collected during a first testing process. A first signature is determined for the integrated circuit, based on the set of parameters collected during the first testing process. The first signature and other information are associated with the integrated circuit. The integrated circuit is diced. The set of parameters is collected anew during a second testing process. A second signature is determined for the integrated circuit, based on the data set of parameters collected anew during the second testing process. The second signature is compared to multiple first signatures to locate the first signature that substantially matches the second signature. The other information associated with the first signature is associated with the diced integrated circuit.

Parametric device signature

A method for testing integrated circuits having associated position designations, where a predetermined set of input vectors is introduced as test input into the integrated circuits. The output from the integrated circuits in response to the predetermined set of input vectors is sensed, and the output from the integrated circuits is recorded in a wafer map, referenced by the position designations. The output from at least a subset of the integrated circuits is selected and mathematically manipulated to produce a reference value. The output for each of the integrated circuits in the selected subset is individually compared to the reference value, and graded integrated circuits within the selected subset that have output that differs from the reference value by more than a given amount are identified. A classification is assigned to the graded integrated circuits and recorded in the wafer map, referenced by the position designations for the graded integrated circuits.

Test limits based on position

A method of testing an integrated circuit. The thermal energy of the integrated circuit to adjusted to a first temperature, and a first set of electrical characteristics of the integrated circuit are sensed at the first temperature. The first set of electrical characteristics are recorded in association with an identifier for the integrated circuit. The thermal energy of the integrated circuit is adjusted to a second temperature, and a second set of electrical characteristics of the integrated circuit are sensed at the second temperature. The electrical characteristics of the second set correspond to the electrical characteristics of the first set. The second set of electrical characteristics are also recorded in association with the identifier for the integrated circuit. Ratios are created between the corresponding recorded electrical characteristics of the first set and the recorded electrical characteristics of the second set for the integrated circuit, as determined by the identifier for the integrated circuit. A first categorization is applied to the integrated circuit if the ratios are within a first limit range, and a second categorization is applied to the integrated circuit if the ratios are not within the first limit range.

Ratio testing

A method for testing a series of functional blocks within an integrated circuit. Each of the functional blocks in the series is tested to determine a minimum parameter value and a maximum parameter value associated with each of the functional blocks. A minimum parameter delta value is calculated for each of the functional blocks in the series. The minimum parameter delta value is the minimum parameter value associated with a given one of the functional blocks subtracted from the minimum parameter value for a functional block immediately following the given one of the functional blocks in the series. A maximum parameter delta value is also calculated for each of the functional blocks in the series. The maximum parameter delta value is the maximum parameter value associated with the given one of the functional blocks subtracted from the maximum parameter value for the functional block immediately following the given one of the functional blocks in the series. The minimum parameter delta value is compared to a minimum parameter delta value tolerance limit and the maximum parameter delta value is compared to a maximum parameter delta value tolerance limit. The integrated circuit is selectively binned based at least in part on whether the minimum parameter delta value or the maximum parameter delta value violates the delta value tolerance limits.

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Portland, OR, United States of America

Robert Madge