Device and method for inspecting photomasks and products fabricated using the same

• US 7,424,145 B2
• Filed: 06/27/2003
• Issued: 09/09/2008
• Est. Priority Date: 07/09/2002
• Status: Expired due to Fees

• Current Assignee: Fujitsu Microelectronics Limited (Fujitsu Limited)
• Original Assignee: Fujitsu Limited
• Inventors: Horie, Tsutomu, Ohta, Kazutoshi
• Primary Examiner(s): Mehta; Bhavesh
• Assistant Examiner(s): Akhavannik; Hadi
• Application Number:
  US10/607,039
• Publication Number:
  US 20040008880A1
• Time in Patent Office: 1,901 Days
• Field of Search: 382/144, 382/141, 382/147, 716/5
• US Class Current: 382/147
• CPC Class Codes: G01N 21/95607 using a comparative method
• CPC Class Codes: G03F 1/84 Inspecting
• CPC Class Codes: G06T 2207/30148 Semiconductor; IC; Wafer
• CPC Class Codes: G06T 7/0006 using a design-rule based approach

Abstract

An inspection device for photomasks and products fabricated using the same, capable of reducing the time from inspection to repair. A reference data generator generates reference data that is based on design data and includes sensitivity class codes that differentiate designated pattern functions such as signal lines and power supply lines by means of inspection sensitivity. Then an inspection sensitivity setter allocates the desired inspection sensitivity for each sensitivity class code. An image acquiring unit photographs a subject of inspection (e.g., photomask or wafer), and a comparator detects a defect by comparing the photographed image with the reference data. When a defect is found, a reference data extractor extracts the region of the reference data that corresponds to the defect location. A defect registration determinator refers to the sensitivity class codes for the region and determines whether to register the defect. This reduces the number of defects that are registered.

Claims

1. An inspection device that identifies defects on a subject of inspection including photomasks or products fabricated using photomasks, comprising:

a reference data generator that generates reference data that is based on design data and includes sensitivity class codes that are used to differentiate designated pattern functions by inspection sensitivity;

an inspection sensitivity setter that allocates desired inspection sensitivities for said sensitivity class codes;

an image acquiring unit that detects an image of the subject of the inspection and generates data to be inspected;

a comparator that compares said data to be inspected with said reference data and detects a defect;

a reference data extractor that extracts a region of said reference data that corresponds to where said detected defect exists;

a defect registration determinator that refers to said sensitivity class codes in said region and determines whether to register said defect; and

a defect memory that records said defect for which registration has been determined,

the defect registration determinator further;

determines the detected defect is a non-registration defect if the detected defect is smaller than the inspection sensitivities allocated to the sensitivity class codes, and

creates a defect determination range by shifting outwardly an outline of a region associated with each of said pattern functions, and based on overlap of said defect and said defect determination range, determines whether to register said defect.

2. The inspection device according to claim 1, wherein said sensitivity class codes are expressed as at least one of a numeral, symbol, and letter.

3. The inspection device according to claim 1, said defect registration determinator further detects which of said pattern functions said defect is associated with based on said overlap, and based on said inspection sensitivity that has been allocated to said detected pattern function, determines whether to register said defect.

4. The inspection device according to claim 1, wherein said sensitivity class codes are set for regions other than those associated with said pattern functions.

9. The device according to claim 1, wherein the pattern functions are selected from power supply lines, clock signal lines, address signal lines, data input-output signal lines and control signal lines.

5. An inspection method to identify defects on a subject of inspection including photomasks or products fabricated using photomasks, comprising:

generating reference data that is based on design data and includes sensitivity class codes that are used to differentiate designated pattern functions by inspection sensitivity;

allocating desired inspection sensitivities for said sensitivity class codes;

detecting an image of the subject of the inspection and generating data to be inspected;

comparing said data to be inspected with said reference data and detecting a defect;

extracting a region of said reference data that corresponds to where said detected defect exists;

determining whether to register said defect, by referencing the sensitivity class codes of the pattern functions in the extracted region; and

recording said defect for which registration has been determined,

the determining further comprising;

determining the detected defect to be a non-registration defect if the detected defect is smaller than the inspection sensitivities allocated to the sensitivity class codes,

creating a defect determination range by shifting outwardly an outline of a region associated with each of said pattern functions, and

based on overlap of said defect and said defect determination range, determining whether to register said defect.

6. The inspection method according to claim 5, wherein said sensitivity class codes are expressed as at least one of a numeral, symbol, and letter.

7. The inspection method according to claim 5, said determining further comprising:

based on said overlap, detecting which of said pattern functions said defect is associated with; and

based on said inspection sensitivity that has been allocated to said detected pattern function, determining whether to register said defect.

8. The inspection method according to claim 5, wherein said generating sets sensitivity class codes also for regions other than those associated with said pattern functions.

10. The method according to claim 5, wherein the pattern functions are selected from power supply lines, clock signal lines, address signal lines, data input-output signal lines and control signal lines.

11. An inspection method to identify defects, comprising:

generating sensitivity class codes to differentiate designated pattern functions by inspection sensitivity;

allocating desired inspection sensitivities for said sensitivity class codes;

comparing data to be inspected with reference data and detecting a defect; and

determining comprising;

whether to register said defect by referencing the sensitivity class codes of the pattern functions,

determining detected defect to be a non-registration defect if the detected defect is smaller than the inspection sensitivities allocated to the sensitivity class codes,

creating a defect determination range by shifting outwardly an outline of a region associated with each of said pattern functions, and

based on overlap of said defect and said defect determination range, determining whether to register said defect.