# US 8,788,237 B2 · Methods and apparatus for hybrid outlier detection

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- Number: US 8,788,237 B2
- Document ID: US8788237B2
- Status: Granted
- Kind: B2
- Application number: 13/853,686
- Filed: 2013-03-29
- Published: 2013-08-29
- Granted: 2014-07-22
- Earliest claimed: 2002-05-24
- Assignees: Test Acuity Solutions, Inc.
- Applicants: Test Acuity Solutions
- Inventors: Emilio Miguelanez; Greg LaBonte
- Web page: https://patentgrep.com/patent/US8788237B2

## CPC

- G06F 17/18: for evaluating statistical data {, e.g. average values, frequency distributions, probability functions, regression analysis (forecasting specially adapted for a specific administrative, business or logistic context G06Q10/04)}
- G01R 31/2836: {Fault-finding or characterising (G01R31/2822 - G01R31/2831 take precedence)}
- G01R 31/2894: {Aspects of quality control [QC] (G01R31/31718 takes precedence; program control for QC G05B19/41875)}
- G01R 31/31718: {Logistic aspects, e.g. binning, selection, sorting of devices under test, tester/handler interaction networks, Test management software, e.g. software for test statistics or test evaluation, yield analysis (mechanical aspects G01R31/2808, G01R31/2851)}
- G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N)
- G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12)

## Abstract

Methods and apparatus for data analysis according to various aspects of the present invention are configured to identify statistical outliers in test data for components, including hybrid outliers representing outliers within subsets of larger data populations. A method and apparatus according to various aspects of the present invention may operate in conjunction with a test system having a tester, such as automatic test equipment (ATE) for testing semiconductors.

## Claims

### Claim 1

A test data analysis system for analyzing test data for multiple components fabricated on a wafer, comprising:
a memory configured to store the test data; and
a computer having access to the memory capable of retrieving the test data from the memory, and comprising a hybrid outlier system capable of, for each of a plurality of test data for each of a plurality of components:
selecting a central component from the plurality of components;
selecting a plurality of local components in a local area near the central component;
determining a derived value of the test data for the plurality of local components;
comparing the test data for the central component to the derived value for the plurality of local components; and
identifying whether the test data for the central component represents a hybrid outlier according to the comparison of the test data for the central component to the derived value for the plurality of local components.

### Claim 2 (depends on 1)

A test data analysis system according to claim 1, wherein the hybrid outlier system is configured to normalize the test data for the central component and the local components.

### Claim 3 (depends on 2)

A test data analysis system according to claim 2, wherein the hybrid outlier system is configured to compare the test data for the central component to the derived value for the plurality of test components by comparing the normalized test data for the central component to the derived value for the plurality of test components.

### Claim 4 (depends on 2)

A test data analysis system according to claim 2, wherein the test data comprises test data generated using multi-site testing, and wherein the hybrid outlier system is configured to normalize the test data for the central component and the local components to counter an inconsistency induced by the multi-site testing.

### Claim 5 (depends on 1)

A test data analysis system according to claim 1, wherein the computer comprises an outlier identification system communicatively linked with the hybrid outlier system, and wherein the outlier identification system is configured to remove a global outlier from the test data before the hybrid outlier system identifies whether the test data for the central component represents the hybrid outlier.

### Claim 6 (depends on 1)

A test data analysis system according to claim 1, wherein the derived value comprises an average value for the plurality of local components.

### Claim 7 (depends on 1)

A test data analysis system according to claim 1, wherein the hybrid outlier system is configured to select the plurality of local components according to a pattern, and wherein the hybrid outlier system is configured to automatically increase a size of the pattern until a minimum number of local components satisfying a selected criterion are within the pattern.

### Claim 8

A computer-implemented method for analyzing test data, stored in a memory accessible by a computer, for multiple components fabricated on a wafer, comprising:
selecting, by the computer, a central component from the multiple components;
selecting, by the computer, a plurality of local components in a local area near the central component;
retrieving, by the computer, the test data for the selected components from the memory;
determining, by the computer, a derived value of the test data for the plurality of local components;
comparing, by the computer, the test data for the central component to the derived value for the plurality of local components; and
identifying, by the computer, whether the test data for the central component represents a hybrid outlier according to the comparison of the test data for the central component to the derived value for the plurality of local components.

### Claim 9 (depends on 8)

A computer-implemented method for analyzing test data according to claim 8, further comprising normalizing, by the computer, the test data for the central component and the local components on the wafer.

### Claim 10 (depends on 9)

A computer-implemented method for analyzing test data according to claim 9, wherein comparing the test data for the central component to the derived value for the plurality of test components comprises comparing the normalized test data for the central component to the derived value for the plurality of test components.

### Claim 11 (depends on 9)

A computer-implemented method for analyzing test data according to claim 9, wherein: the test data comprises test data generated using multi-site testing; and normalizing the test data for the central component and the local components comprises normalizing the test data to counter an inconsistency induced by the multi-site testing.

### Claim 12 (depends on 8)

A computer-implemented method for analyzing test data according to claim 8, wherein the derived value comprises an average value for the plurality of local components.

### Claim 13 (depends on 8)

A computer-implemented method for analyzing test data according to claim 8, further comprising removing, by the computer, a global outlier from the test data before identifying whether the test data for the central component represents the hybrid outlier.

### Claim 14 (depends on 8)

A computer-implemented method for analyzing test data according to claim 8, wherein selecting the plurality of local components comprises selecting the plurality of local components according to a pattern, and further comprising automatically increasing a size of the pattern, by the computer, until a minimum number of local components satisfying a selected criterion are within the pattern.

### Claim 15

A non-transitory computer-readable medium containing computer instructions stored therein for causing a computer processor to perform analysis on test data, stored in a memory accessible by the computer, for components on a wafer, wherein the instructions cause the computer to:
select, a central component;
select a plurality of local components in a local area near the central component;
retrieve the test data for the selected components from the memory;
determine a derived value of the test data for the plurality of local components;
compare the test data for the central component to the derived value for the plurality of local components; and
identify whether the test data for the central component represents a hybrid outlier according to the comparison of the test data for the central component to the derived value for the plurality of local components.

### Claim 16 (depends on 15)

A non-transitory computer-readable medium according to claim 15, wherein the instructions further cause the computer to normalize the test data for the central component and the local components on the wafer.

### Claim 17 (depends on 16)

A non-transitory computer-readable medium according to claim 16, wherein the instructions further cause the computer to compare the test data for the central component to the derived value for the plurality of test components by comparing the normalized test data for the central component to the derived value for the plurality of test components.

### Claim 18 (depends on 16)

A non-transitory computer-readable medium according to claim 16, wherein the test data comprises test data generated using multi-site testing, and wherein the instructions further cause the computer to normalize the test data for the central component and the local components to counter an inconsistency induced by the multi-site testing.

### Claim 19 (depends on 15)

A non-transitory computer-readable medium according to claim 15, wherein the derived value comprises an average value for the plurality of local components.

### Claim 20 (depends on 15)

A non-transitory computer-readable medium according to claim 15, wherein the instructions further cause the computer to remove a global outlier from the test data before identifying whether the test data for the central component represents the hybrid outlier.

### Claim 21 (depends on 15)

A non-transitory computer-readable medium according to claim 15, wherein the plurality of local components are selected according to a pattern, and wherein the instructions cause the computer to automatically increase a size of the pattern until a minimum number of local components satisfying a selected criterion are within the pattern.