Method and system for analyzing bitmap test data

• US 20040083407A1
• Filed: 10/25/2002
• Published: 04/29/2004
• Est. Priority Date: 10/25/2002
• Status: Active Grant

• Current Assignee: Onto Innovation Inc.
• Original Assignee: Inspex Inc. (Hamamatsu Photonics KK)
• Inventors: Song, Xin, Hitelman, Stewart, Hsu, Chin-Jung
• Granted Patent: US 6,842,866 B2
• Time in Patent Office: Days
• US Class Current: 714/27
• CPC Class Codes: G06T 7/0004 Industrial image inspection

Abstract

A system for analyzing bitmap test data includes a fault shape analyzer which continuously and automatically receives bitmap test data. In use, the user creates at least one failure pattern analysis order to be performed by the fault shape analyzer, the order specifying a particular failure pattern to be identified. Based on the order, the fault shape analyzer creates a bitmap display of a user-specified sector using selected bitmap test data. The fault shape analyzer identifies the user-specified failure pattern in the bitmap display by multiplying, at various locations, the bitmap display in the frequency domain and the failure pattern in the frequency domain. A comparison between the product of the multiplication process and the failure pattern is performed to locate failure patterns in the bitmap display. Failure patterns identified from the comparison process are saved as defect files which, in turn, are stored in a failure pattern classification database.

Claims

1. A method for analyzing bitmap test data, said method comprising the steps of:

(a) establishing a first failure pattern analysis order to be performed, the first failure pattern analysis order specifying a particular failure pattern to be identified, the failure pattern having at least one base fault shape,

(b) converting said bitmap test data into a bitmap display based on the first failure pattern analysis order, and

(c) identifying in the frequency domain the failure pattern of the first failure pattern analysis order in said bitmap display.

2. The method of claim 1 wherein said failure pattern analysis order specifies the particular sector within said bitmap display for which said identification step is to be performed.

3. The method of claim 1 further comprising the step of establishing a second failure pattern analysis order to be performed, the second failure pattern analysis order specifying a particular failure pattern to be identified

4. The method of claim 3 wherein said first and second failure pattern analysis orders are ranked in terms of priority, the failure pattern analysis order of higher priority being performed before the failure pattern analysis order of lower priority.

5. The method of claim 1 further comprising the step of, upon completion of said identification step, storing failure patterns identified in said bitmap display in a defect file.

6. The method of claim 1 wherein, if the failure pattern specified in said first failure pattern analysis order is deterministic, said identification step comprises the step of:

(a) representing the sector of the bitmap display specified in the first failure pattern analysis order as a bitmap matrix in the spatial domain,

(b) converting said bitmap matrix from the spatial domain to the frequency domain,

(c) representing the failure pattern specified in the first failure pattern analysis order as a pattern mask in the spatial domain,

(d) converting said pattern mask from the spatial domain to the frequency domain,

(e) multiplying together the bitmap matrix in the frequency domain and the pattern mask in the frequency domain to yield a multiplication matrix in the frequency domain,

(f) converting said multiplication matrix in the frequency domain to the spatial domain, and

(g) calculating whether said multiplication matrix in the spatial domain directly matches the pattern mask in the spatial domain.

7. The method of claim 6 wherein said step of converting said bitmap matrix from the spatial domain to the frequency domain is accomplished by performing a Fourier Transform on said bitmap matrix in the spatial domain to yield the bitmap matrix in the frequency domain.

8. The method of claim 6 wherein said step of converting said pattern mask from the spatial domain to the frequency domain is accomplished by performing a Fourier Transform on said pattern mask in the spatial domain to yield the pattern mask in the frequency domain.

9. The method of claim 6 wherein said step of converting said multiplication matrix from the frequency domain to the spatial domain is accomplished by performing an inverse Fourier Transform on said multiplication matrix in the frequency domain to yield the multiplication matrix in the spatial domain.

10. The method of claim 6 wherein said calculation step is accomplished using the following equation:

11. The method of claim 10 wherein, if in said calculation step the equation is satisfied for location (M,N), a defect with pattern and location information will be generated and will be saved to a defect file.

12. The method of claim 1 wherein, if the failure pattern specified in said first failure pattern analysis order is non-deterministic, said identification step comprises the step of:

(a) representing the sector of the bitmap display specified in the first failure pattern analysis order as a bitmap matrix in the spatial domain,

(b) converting said bitmap matrix from the spatial domain to the frequency domain,

(c) representing the failure pattern specified in the first failure pattern analysis order as a pattern mask in the spatial domain,

(d) converting said pattern mask from the spatial domain to the frequency domain,

(e) multiplying together the bitmap matrix in the frequency domain and the pattern mask in the frequency domain to yield a multiplication matrix in the frequency domain,

(f) converting said multiplication matrix in the frequency domain to the spatial domain, and

(g) calculating whether said multiplication matrix in the spatial domain falls within the range of the pattern mask in the spatial domain as defined in the first failure pattern analysis order.

13. The method of claim 12 wherein said step of converting said bitmap matrix from the spatial domain to the frequency domain is accomplished by performing a Fourier Transform on said bitmap matrix in the spatial domain to yield the bitmap matrix in the frequency domain.

14. The method of claim 12 wherein said step of converting said pattern mask from the spatial domain to the frequency domain is accomplished by performing a Fourier Transform on said pattern mask in the spatial domain to yield the pattern mask in the frequency domain.

15. The method of claim 12 wherein said step of converting said multiplication matrix from the frequency domain to the spatial domain is accomplished by performing an inverse Fourier Transform on said multiplication matrix in the frequency domain to yield the multiplication matrix in the spatial domain.

16. The method of claim 12 wherein said calculation step is accomplished using the following equation:

17. The method of claim 16 wherein, if in said calculation step said multiplication matrix in the spatial domain directly matches the pattern mask in the spatial domain, the multiplication matrix in the spatial domain is saved as a defect file.

18. The method of claim 1 wherein, if the failure pattern specified in said first failure pattern analysis order is decoupled, said identification step comprises the step of:

(a) identifying in the frequency domain each base fault shape of the failure pattern in the bitmap display, and

(b) searching for all possible combinations of the base fault shapes of the failure pattern which were identified in the frequency domain in the bitmap display.

19. The method of claim 18 wherein, for each base fault shape in the decoupled failure pattern definition which is deterministic, said identification step comprises the step of:

(a) representing the sector of the bitmap display specified in the first failure pattern analysis order as a bitmap matrix in the spatial domain,

(b) converting said bitmap matrix from the spatial domain to the frequency domain,

(c) representing said failure pattern as a pattern mask in the spatial domain,

(d) converting said pattern mask from the spatial domain to the frequency domain,

(e) multiplying together the bitmap matrix in the frequency domain and the pattern mask in the frequency domain to yield a multiplication matrix in the frequency domain,

(f) converting said multiplication matrix in the frequency domain to the spatial domain, and

(g) calculating whether said multiplication matrix in the spatial domain directly matches said pattern mask in the spatial domain.

20. The method of claim 18 wherein, for each base fault shape in the decoupled failure pattern definition which is non-deterministic, said identification step comprises the step of:

(a) representing the sector of the bitmap display specified in the first failure pattern analysis order as a bitmap matrix in the spatial domain,

(b) converting said bitmap matrix from the spatial domain to the frequency domain,

(c) representing said failure pattern as a pattern mask in the spatial domain,

(d) converting said pattern mask from the spatial domain to the frequency domain,

(e) multiplying together the bitmap matrix in the frequency domain and the pattern mask in the frequency domain to yield a multiplication matrix in the frequency domain,

(f) converting said multiplication matrix in the frequency domain to the spatial domain, and

(g) calculating whether said multiplication matrix in the spatial domain falls within the range of said pattern mask in the spatial domain as defined in the first failure pattern analysis order.