Method and apparatus for fast automated failure classification for semiconductor wafers

• US 6,963,813 B1
• Filed: 09/13/2000
• Issued: 11/08/2005
• Est. Priority Date: 09/13/2000
• Status: Expired due to Fees

• Current Assignee: Polaris Innovations Limited (Wi-LAN Inc.)
• Original Assignee: Qimonda AG (Infineon Technologies AG)
• Inventors: Wohlfahrt, Joerg, Rathei, Dieter, Hladschik, Thomas, Oswald, Peter
• Primary Examiner(s): Barlow, John
• Assistant Examiner(s): PRETLOW, DEMETRIUS R
• Application Number:
  US09/660,703
• Time in Patent Office: 1,882 Days
• Field of Search: 702/82, 702/81, 702/84, 702/33, 702/35, 702/117, 702/118, 438/17, 438/14, 706/20, 714/799, 700/110, 700/121
• US Class Current: 702/82
• CPC Class Codes: H01L 22/20 Sequence of activities consisting of a plurality of measurements, corrections, marking or sorting steps

Abstract

A method for classifying patterns of failcodes on a semiconductor wafer, in accordance with the present invention, includes determining failcodes for chips on the wafer and checking adjacent chips for each chip on the wafer having a failcode to determine a failcode pattern having a defined number of chips.

Claims

1. A method for classifying patterns of failcodes on a semiconductor wafer, comprising the steps of:

determining failcodes for chips on the wafer;

checking adjacent chips for each chip on the wafer having a failcode to determine a failcode pattern having a defined number of chips, wherein the step of checking comprises determining once for each chip having a failcode, adjacent chips having the same failcode, tracking adjacent chips having the same failcode, and determining a pattern of chips having the same failcode upon tracking a defined number of adjacent chips having the same failcode; and

outputting the failcode pattern to analyze the wafer.

2. The method of claim 1, wherein the defined number of adjacent chips having the same failcode is determined in accordance with a cluster size, which serves as a threshold for recognition of a pattern.

3. The method of claim 2, wherein cluster size is adjustable to provide a sensitivity for pattern detection.

4. The method of claim 1, wherein the step of checking adjacent chips for each chip on the wafer includes flagging each chip as a good chip, part of a detected pattern or under investigation.

5. A method for classifying patterns of failcodes on a semiconductor wafer, comprising steps of:

providing failure information from a wafer tester;

determining failcodes for chips on the water by employing the failure information,

checking adjacent chips for each chip on the wafer to determine if the adjacent chips have a same failcode;

determining a pattern of chips having the same failcode upon tracking a defined number of chips; and

outputting the failcode pattern to analyze the wafer.

6. The method of claim 5, wherein the step of checking adjacent chips further comprises the steps of:

determining once for each chip having a failcode adjacent chips having the same failcode.

7. The method of claim 5, wherein the step of checking adjacent chips includes tracking adjacent chips having the same failcode until a determination of a pattern is made.

8. The method of claim 5, wherein the defined number of chips is determined in accordance with a cluster size, which serves as a threshold for recognition of a pattern.

9. The method of claim 8, wherein cluster size is adjustable to provide a sensitivity for pattern detection.

10. The method of claim 5, wherein the step of checking adjacent chips includes flagging each chip as a good chip, part of a detected pattern or under investigation.

11. A program storage device readable by machine, tangibly embodying a program of instructions executable by the machine to perform method steps for classifying patterns of failcodes on a semiconductor wafer, the method steps comprising:

determining failcodes for chips on the wafer;

checking adjacent chips for each chip on the wafer having a failcode to determine a failcode pattern having a defined number of chips, wherein the step of checking comprises determining once for each chip having a failcode, adjacent chips having the same failcode, tracking adjacent chips having the same failcode, and determining a pattern of chips having the same failcode upon tracking a defined number of adjacent chips having the same failcode; and

outputting the failcode pattern to analyze the wafer.

12. The program storage device of claim 11, wherein the defined number of adjacent chips having the same failcode is determined in accordance with a cluster size, which serves as a threshold for recognition of a pattern.

13. The program storage device of claim 12, wherein cluster size is adjustable to provide a sensitivity for pattern detection.

14. The program storage device of claim 11, wherein the step of checking adjacent chips for each chip on the wafer includes flagging each chip as a good chip, part of a detected pattern or under investigation.

15. A computer program product comprising a computer usable medium having a computer readable program code embodied therein for a recursive classification of semiconductor wafers, the computer readable program code in the computer program product comprising:

computer readable program code for causing a computer to determine whether a chip on the wafer has a pass or a failcode;

computer readable program code for causing the computer to determine a characteristic failcode for each chip having a failcode;

computer readable program code for causing the computer to add a first chip to a temporary array, if the first chip has a failcode,

computer readable program code for causing the computer to determine adjacent chips having the same failcode as the first chip;

computer readable program code for causing the computer to add an adjacent second chip having the same failcode to the temporary array; and

computer readable program code for causing the computer to classify the temporary array of chips having the same failcode as a pattern upon identifying at least a predefined number of chips in the temporary array.