Test data analyzing system and test data analyzing program

• US 20070021855A1
• Filed: 07/11/2006
• Published: 01/25/2007
• Est. Priority Date: 07/11/2005
• Status: Active Grant

• Current Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.)
• Original Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.)
• Inventors: Ono, Makoto, Konishi, Junko
• Granted Patent: US 7,424,336 B2
• Time in Patent Office: Days
• US Class Current: 700/110
• CPC Class Codes: G05B 19/41875 characterised by quality surveillance of production
• CPC Class Codes: G05B 2219/32196 Store audit, history of inspection, control and workpiece data into database
• CPC Class Codes: G05B 2219/32206 Selection from a lot of workpieces to be inspected
• CPC Class Codes: G05B 23/024 Quantitative history assessment, e.g. mathematical relationships between available data; Functions therefor; Principal component analysis [PCA]; Partial least square [PLS]; Statistical classifiers, e.g. Bayesian networks, linear regression or correlation analysis; Neural networks
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
• CPC Class Codes: Y02P 90/80 Management or planning

Abstract

Disclosed is a test data analyzing method and system for use in estimation of a defect cause of a product, such as, an integrated circuit, a liquid crystal display, an optical transceiver, a thin film magnetic head, etc., which is fabricated through plural processes. The estimation of a defect cause is achieved by selecting a wafer number to be analyzed, reading test data, reading fabrication line data, counting frequency of machine codes by wafers, grouping test data by machine codes or frequencies, comparing test data distributions between groups by machine codes, and comparing results between machine codes.

Claims

1. A test data analyzing system for estimating a defect cause in a product that is fabricated through plural processes, the system comprising:

a fabrication line data management unit, which records information of machine code numbers specifying fabrication machines of a fabrication process the product passes through as fabrication line data for the respective products;

a test data management unit, which stores test data obtained from an inspection done on the product by an inspection machine; and

a data analysis unit, which reads a fabrication line data of each of the products, groups the products per showing frequency by machine code numbers, reads the test data corresponding to each product to prepare a test data distribution for each group, and calculates a probability distribution of the ratio of variance of the test data distribution per showing frequency by machine code numbers,

wherein, the data analysis unit displays a correlation diagram of the showing frequency and the test data as designated by a user.

2. The system of claim 1, wherein the data analysis unit calculates a significance probability P value from the probability of distribution of the ratio of variance of the test data distribution per showing frequency by the respective machine code numbers, and displays the correlation diagram of the showing frequency and the test data, on the basis of the order sorted by the significance probability P value as designated by a user.

3. The system of claim 1, wherein the data analysis unit selects, as a candidate of a fabrication machine with a defect cause, only the machine code number that has a minus coefficient of correlation in a scatter diagram with the horizontal axis representing showing frequency and the vertical axis representing test data.

4. A test data analyzing program executed to estimate a defect cause of a product that is fabricated through plural processes, the program comprising:

a fabrication line data reading process for reading fabrication line data that includes information of machine code numbers specifying fabrication machines of a fabrication process the product passes through;

a test data reading process for reading test data obtained from an inspection on the product by an inspection machine;

a process for grouping products, out of the fabrication line data, per showing frequency by machine code numbers, and for preparing a test data distribution of the respective groups;

a process for calculating a significance probability P value from a probability distribution of the ratio of variance of the test data distribution per showing frequency by the machine code numbers; and

a process for displaying a correlation diagram of the showing frequency and the test data, on the basis of the order sorted by the significance probability P value.

5. The program of claim 4, wherein the significance probability P value is calculated by selecting, as a candidate of a fabrication machine with a defect cause, only the machine code number that has a minus coefficient of correlation in a scatter diagram with the horizontal axis representing showing frequency and the vertical axis representing test data.