Method and apparatus to accurately correlate defect coordinates between photomask inspection and repair systems

• US 6,373,976 B1
• Filed: 07/24/1998
• Issued: 04/16/2002
• Est. Priority Date: 05/16/1997
• Status: Expired due to Fees

• Current Assignee: Micron Technology, Inc.
• Original Assignee: Micron Technology, Inc.
• Inventors: Yang, Baorui, Pierrat, Christophe
• Primary Examiner(s): Mancuso, Joseph
• Assistant Examiner(s): Bali, Vikkram
• Application Number:
  US09/122,252
• Time in Patent Office: 1,362 Days
• Field of Search: 382/151, 382/144, 382/155, 382/141, 382/143, 382/147, 382/146, 382/149, 348/87, 348/126, 438/16, 430/22
• US Class Current: 382/151
• CPC Class Codes: G03F 1/42 Alignment or registration features, e.g. alignment marks on the mask substrates
• CPC Class Codes: G03F 1/72 Repair or correction of mask defects
• CPC Class Codes: G03F 1/84 Inspecting
• CPC Class Codes: G03F 7/70425 Imaging strategies, e.g. for increasing throughput or resolution, printing product fields larger than the image field or compensating lithography- or non-lithography errors, e.g. proximity correction, mix-and-match, stitching or double patterning
• CPC Class Codes: G03F 7/70616 Monitoring the printed patterns
• CPC Class Codes: G03F 7/7065 Defects, e.g. optical inspection of patterned layer for defects
• CPC Class Codes: G03F 9/70 for microlithography measuring printed patterns for monitoring overlay G03F7/70633 or focus G03F7/70641; projection system adjustment G03F7/70258; position control G03F7/70775

Abstract

A method and apparatus for calibrating the coordinate systems of photomask processing machines improves processing efficiency and the quality of resulting photomasks. A test pattern is printed on an unproductive area of the photomask. The test pattern is used to calibrate the coordinate system of each processing machine on which the photomask is mounted. Using the test pattern as a common reference point enables points located using one processing machine to be quickly and accurately found on a second processing machine. The test pattern is also used as a reference for other metrology measurements.

Claims

1. An apparatus for establishing a coordinate system, comprising:

an optically readable media having at least one test pattern containing at least one reference point, including a first test pattern with a first reference point;

a first processing machine for reading the media and locating the test pattern;

a coordinate initialization process operable for initializing a default coordinate system of the first processing machine by utilizing the at least one reference point and producing therefrom an initialized default coordinate system; and

a second processing machine having a second coordinate system and operable for receiving a plurality of coordinates from the first processing machine and for initializing the second coordinate system by utilizing the at least one reference point.

2. The apparatus of claim 1, wherein the first test pattern is positioned on a non-productive area of the photomask.

3. The apparatus of claim 1, wherein the visually readable media is a photomask.

4. The apparatus of claim 1, wherein the first processing machine is a photomask inspection machine.

5. The apparatus of claim 1, wherein the first reference point is an origin point for the initialized default coordinate system.

6. The apparatus of claim 1, wherein the first reference point is a calibration point for the initialized default coordinate system.

7. The apparatus of claim 1, wherein the first reference point is a correlation point for the initialized default coordinate system.

8. The apparatus of claim 1, wherein the coordinate initialization process utilizes multiple reference points to initialize the initialized default coordinate system.

9. The apparatus of claim 1, further comprising a positioning process for identifying a location of each of a plurality of points on the media in terms of the initialized default coordinate system.

10. The apparatus of claim 9, further comprising a mass storage device for storing the locations of each of the plurality of points.

11. An apparatus for establishing a coordinate system, comprising:

an optically readable media having at least one test pattern containing at least one reference point, including a first test pattern with a first reference point;

a first processing machine for reading the media and locating the test pattern;

a first coordinate initialization process for initializing a first default coordinate system of the first processing machine by utilizing at least one reference point;

a first positioning process for identifying a location of each of a plurality of points on the media in terms of the first initialized coordinate system;

a first mass storage device for storing the locations of each of the plurality of points;

a data transfer process for transferring the locations of each of the plurality of points to a second processing machine; and

the second processing machine having a second coordinate system and operable for receiving a plurality of coordinates from the first processing machine and for initializing the second coordinate system by utilizing the at least one reference point.

12. The apparatus of claim 11, wherein the second processing machine is a photomask repair machine.

13. The apparatus of claim 11, further comprising a second mass storage device for storing the locations of each of the plurality of points transferred to the second processing machine via the data transfer means.

14. An apparatus for establishing a coordinate system, comprising:

an optically readable media having at least one test pattern containing at least one reference point, including a first test pattern with a first reference point;

a first processing machine for reading the media and locating the test pattern;

a first coordinate initialization process for initializing a first default coordinate system of the first processing machine by utilizing at least one reference point;

a first positioning process for identifying a location of each of a plurality of points on the media in terms of the first initialized coordinate system;

a first mass storage device for storing the locations of each of the plurality of points; and

a data transfer process for transferring the locations of each of the plurality of points to a second processing machine;

a second mass storage device for storing the locations of each of the plurality of points transferred to the second processing machine via the data transfer process; and

a second coordinate initialization process for initializing a second default coordinate system of the second processing machine by utilizing the at least one reference point.

15. An apparatus for establishing a coordinate system, comprising:

an optically readable media having at least one test pattern containing at least one reference point, including a first test pattern with a first reference point;

a first processing machine for reading the media and locating the test pattern;

a first coordinate initialization process for initializing a first default coordinate system of the first processing machine by utilizing at least one reference point;

a first positioning process for identifying a location of each of a plurality of points on the media in terms of the first initialized coordinate system;

a first mass storage device for storing the locations of each of the plurality of points; and

a data transfer process for transferring the locations of each of the plurality of points to a second processing machine;

a second mass storage device for storing the locations of each of the plurality of points transferred to the second processing machine via the data transfer process;

a second coordinate initialization process for initializing a second default coordinate system of the second processing machine by utilizing at least one reference point; and

a second positioning process for identifying the locations of each of the plurality of points stored in the second mass storage device.

16. An apparatus for establishing a coordinate system, comprising:

an optically readable media having at least one test pattern containing at least one reference point, including a first test pattern with a first reference point;

a first processing machine for reading the media and locating the test pattern;

a first coordinate initialization process for initializing a first default coordinate system of the first processing machine by utilizing at least one reference point;

a first positioning process for identifying a location of each of a plurality of points on the media in terms of the first initialized coordinate system;

a data transfer process for transferring the locations of each of the plurality of points to a second processing machine;

a second coordinate initialization process for initializing a second default coordinate system of the second processing machine by utilizing at least one reference point; and

a second positioning process for identifying the locations of each of the plurality of points transferred to the second processing machine via the data transfer process.

17. An apparatus for establishing a coordinate system, comprising:

a photomask having at least one test pattern containing at least one reference point, including a first test pattern with a first reference point;

a first photomask processing machine for reading the photomask and locating the test pattern;

first coordinate initialization circuitry for initializing a first default coordinate system of the first photomask processing machine to the first reference point;

first positioning circuitry for identifying a location of each of a plurality of points on the photomask in terms of the first initialized coordinate system;

a communication path for transferring the locations of each of the plurality of points to a second photomask processing machine;

second coordinate initialization circuitry for converting a second default coordinate system of the second photomask processing machine to the first initialized coordinate system; and

second positioning circuitry for identifying the locations of each of the plurality of points transferred to the second photomask processing machine via the communication path.

18. An apparatus for establishing a coordinate system, comprising:

a photomask having at least one test pattern containing at least one reference point, including a first test pattern with a first reference point;

a first photomask processing machine for reading the photomask and locating the test pattern;

first coordinate initialization circuitry for initializing a first default coordinate system of the first photomask processing machine to the first reference point;

first positioning circuitry for identifying a location of each of a plurality of points on the photomask in terms of the first initialized coordinate system;

a first mass storage device for storing the location of each of the plurality of points;

a data transfer device for transferring the locations of each of the plurality of points to a second photomask processing machine, the data transfer device including but not limited to portable magnetic media used in conjunction with mass storage devices;

a second mass storage device for storing the location of each of the plurality of points transferred via the data transfer device;

second coordinate initialization circuitry for converting a second default coordinate system of the second photomask processing machine to the first initialized coordinate system; and

second positioning circuitry for identifying the locations of each of the plurality of points transferred to the second photomask processing machine via the data transfer device.

19. An apparatus for establishing a coordinate system, comprising:

a photomask having at least one test pattern containing at least one reference point, including a first test pattern with a first reference point;

a first photomask processing machine for reading the photomask and locating the test pattern;

first positioning circuitry for identifying a location of each of a plurality of points and the first reference point on the photomask in terms of a first default coordinate system;

a communication path for transferring the locations of each of the plurality of points to a second photomask processing machine;

coordinate initialization circuitry for initializing a second default coordinate system of the second photomask processing machine to the first default coordinate system; and

second positioning circuitry for identifying the locations of each of the plurality of points transferred to the second photomask processing machine via the communication path.

20. An apparatus for establishing a coordinate system, comprising:

a photomask having at least one test pattern containing at least one reference point, including a first test pattern with a first reference point;

a first photomask processing machine for reading the photomask and locating the test pattern;

first positioning circuitry for identifying a location of each of a plurality of points and the first reference point on the photomask in terms of a first default coordinate system;

a first mass storage device for storing the location of each of the plurality of points and the first reference point;

a data transfer device for transferring the locations of each of the plurality of points to a second photomask processing machine, the data transfer device including but not limited to portable magnetic media used in conjunction with mass storage devices;

a second mass storage device for storing the location of each of the plurality of points and the first reference point transferred via the data transfer device;

coordinate initialization circuitry for initializing a second default coordinate system of the second photomask processing machine to the first default coordinate system; and

second positioning circuitry for identifying the locations of each of the plurality of points transferred to the second photomask processing machine via the data transfer device.

21. An apparatus for establishing a coordinate system, comprising:

a photomask having at least one test pattern containing at least one reference point, including a first test pattern with a first reference point at a known location;

a first photomask processing machine for reading the photomask and locating the test pattern;

first coordinate initialization circuitry for initializing a first default coordinate system of the first photomask processing machine such that the known location of the first reference point is correct;

first positioning circuitry for identifying a location of each of a plurality of points on the photomask in terms of the first initialized coordinate system;

a communication path for transferring the locations of each of the plurality of points to a second photomask processing machine;

second coordinate initialization circuitry for initializing a second default coordinate system of the second photomask processing machine such that the known location of the first reference point is correct; and

second positioning circuitry for identifying the locations of each of the plurality of points transferred to the second photomask processing machine via the communication path.

22. An apparatus for establishing a coordinate system, comprising:

a photomask having at least one test pattern containing at least one reference point, including a first test pattern with a first reference point at a known location;

a first photomask processing machine for reading the photomask and locating the test pattern;

first coordinate initialization circuitry for initializing a first default coordinate system of the first photomask processing machine such that the known location of the first reference point is correct;

first positioning circuitry for identifying a location of each of a plurality of points on the photomask in terms of the first initialized coordinate system;

a first mass storage device for storing the location of each of the plurality of points and the first reference point;

a data transfer device for transferring the locations of each of the plurality of points to a second photomask processing machine, the data transfer device including but not limited to portable magnetic media used in conjunction with mass storage devices;

a second mass storage device for storing the location of each of the plurality of points and the first reference point transferred via the data transfer device;

second coordinate initialization circuitry for initializing a second default coordinate system of the second photomask processing machine such that the known location of the first reference point is correct; and

second positioning circuitry for identifying the locations of each of the plurality of points transferred to the second photomask processing machine via the data transfer device.