Pattern comparison inspection system and method employing gray level bit map

• US 6,069,971 A
• Filed: 06/02/1997
• Issued: 05/30/2000
• Est. Priority Date: 12/18/1996
• Status: Expired due to Fees

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Kanno, Makoto, Moriizumi, Koichi
• Primary Examiner(s): MEHTA, BHAVESH M
• Application Number:
  US08/866,244
• Time in Patent Office: 1,093 Days
• Field of Search: 382/144, 382/220, 382/149, 382/217, 382/209, 382/218, 382/219, 348/130, 348/125, 348/126, 348/129, 430/5, 430/30
• US Class Current: 382/144
• CPC Class Codes: G03F 1/20 Masks or mask blanks for imaging by charged particle beam [CPB] radiation, e.g. by electron beam; Preparation thereof
• CPC Class Codes: G03F 1/84 Inspecting
• CPC Class Codes: H01J 2237/3175 Lithography
• CPC Class Codes: H01J 37/3026 Patterning strategy

Abstract

A pattern comparison inspection system includes: an occupancy calculating portion for dividing pattern data into pixel regions and calculating a ratio of divided pattern data to a pixel region; a gray level bit map generating portion for generating a gray level bit map based on the ratio of the divided pattern data; and a bit map comparing portion for making a comparison between a gray level bit map for design pattern data and a gray level bit map for pattern data for an electron beam patterning system both generated by the occupancy calculating portion and the gray level bit map generating portion to determine whether the pattern data for an electron beam patterning system matches the design pattern data.

Claims

1. A pattern comparison inspection system comprising:

occupancy calculating means for dividing pattern data into pixel regions and calculating a ratio of the divided pattern data to said pixel region;

gray level bit map generating means for generating a gray level bit map based on the ratio of said divided pattern data; and

bit map comparing means for making a comparison between a gray level bit map for design pattern data and a gray level bit map for pattern data for an electron beam patterning system both generated by said occupancy calculating means and said gray level bit map generating means to determine whether said pattern data for an electron beam patterning system matches said design pattern data.

2. The pattern comparison inspection system according to claim 1, wherein said bit map comparing means calculates an absolute value of a difference between a pixel value of a gray level bit map for said design pattern data and a pixel value of a gray level bit map for said pattern data for an electron beam patterning system to identify the pixel value of the gray level bit map for said pattern data for an electron beam patterning system as non-match when said absolute value of the pixel value difference exceeds a predetermined significant difference value, as warned when said absolute value of the pixel value difference does not exceed said significant difference value and exceeds a predetermined tolerable difference value, and as match when said absolute value of the pixel value difference does not exceed said tolerable difference value.

4. The pattern comparison inspection system according to claim 1, further comprising amount-of-sizing adjusting means for adjusting a pattern difference due to uniform sizing in a gray level bit map, wherein

said bit map comparing means makes a comparison between a gray level bit map for said design pattern data and a gray level bit map for said pattern data for an electron beam patterning system adjusted by said amount-of-sizing adjusting means to determine whether said pattern data for an electron beam patterning system matches said design pattern data.

5. The pattern comparison inspection system according to claim 1, further comprising black-white inversion means for black-white inverting a gray level bit map, wherein

said bit map comparing means makes a comparison between a gray level bit map for said design pattern data and a gray level bit map for said pattern data for an electron beam patterning system black-white inverted by said black-white inversion means to determine whether said pattern data for an electron beam patterning system matches said design pattern data.

6. The pattern comparison inspection system according to claim 1, further comprising comparison and decision value calculating means for calculating a tolerable difference value and a significant difference value from a grid size, amount of sizing and pixel size of said pattern data for an electron beam patterning system, wherein

said bit map comparing means calculates an absolute value of a difference between a pixel value of a gray level bit map for said design pattern data and a pixel value of a gray level bit map for said pattern data for an electron beam patterning system to identify the pixel value of the gray level bit map for said pattern data for an electron beam patterning system as non-match when said absolute value of the pixel value difference exceeds said significant difference value, as warned when said absolute value of the pixel value difference does not exceed said significant difference value and exceeds said tolerable difference value, and as match when said absolute value of the pixel value difference does not exceed said tolerable difference value.

7. The pattern comparison inspection system according to claim 4, wherein said amount-of-sizing adjusting means detects a peripheral edge of a pattern in a gray level bit map and adjusts a pattern difference of only a pixel of the peripheral edge.

8. The pattern comparison inspection system according to claim 1, wherein said bit map comparing means identifies a pixel to be compared with as match or non-match by comparing said pixel to be compared with and eight pixels adjacent to said pixel to be compared with within a gray level bit map for said pattern data for an electron beam patterning system with said pixel to be compared with and pixels to adjacent to said pixel to be compared with within a gray level bit map for said design pattern data.

9. The pattern comparison inspection system according to claim 1, further comprising amount-of-sizing adjusting means for adjusting a pattern difference based on an amount of sizing provided to a gray level bit map for each pattern, wherein

said bit map comparing means makes a comparison between a gray level bit map for said design pattern data and a gray level bit map for said pattern data for an electron beam patterning system adjusted by said amount-of-sizing adjusting means to determine whether said pattern data for an electron beam patterning system matches said design pattern data.

10. The pattern comparison inspection system according to claim 1, further comprising decision result information process means for generating a confirming pattern for distinguishing a pixel identified as non-match from a pixel identified as match.

11. The pattern comparison inspection system according to claim 1, wherein said bit map comparing means detects a peripheral edge of a pattern of pattern data for an electron beam patterning system including a pattern adjacent to a predetermined comparison region at an outside thereof, generates a gray level bit map having pattern sizing adjusted for only a pixel of the peripheral edge and makes a comparison between said gray level bit map for said design pattern data and said adjusted bit map only within said comparison region to determine whether said pattern data for an electron beam patterning system matches said design pattern data.

3. A pattern comparison inspection system comprising:

occupancy calculating means for dividing pattern data into pixel regions and calculating a ratio of the divided pattern data to said pixel region;

gray level bit map generating means for generating a gray level bit map based on the ratio of said divided pattern data; and

multi-exposure detect means for detecting as multi-exposure a pixel region having a ratio of divided pattern data to the pixel region equal to or larger than a predetermined value within a gray level bit map for pattern data for an electron beam patterning system generated by said occupancy calculating means and said gray level bit map generating means.

12. A method of comparing and inspecting a pattern, comprising the steps of:

dividing design pattern data into pixel regions and calculating a ratio of the divided design pattern data to said pixel region;

generating a gray level bit map based on the ratio of said divided design pattern data;

dividing pattern data for an electron beam patterning system into said pixel regions and calculating a ratio of said divided pattern data for an electron beam patterning system to said pixel region;

generating a gray level bit map based on the ratio of said divided pattern data for an electron beam patterning system; and

making a comparison between a gray level bit map for said design pattern data and a gray level bit map for said pattern data for an electron beam patterning system to determine whether said pattern data for an electron beam patterning system matches said design pattern data.

13. A method of comparing and inspecting a pattern, comprising the steps of:

dividing pattern data for an electron beam patterning system into pixel regions and calculating a ratio of said divided pattern data for an electron beam patterning system to said pixel region;

generating a gray level bit map based on the ratio of said divided pattern data for an electron beam patterning system; and

detecting as multi-exposure a pixel region having a ratio of divided pattern data for an electron beam patterning system equal to or more than a predetermined value in a gray level bit map for said pattern data for an electron beam patterning system.

14. A medium having a pattern comparison inspection program recorded thereon, comprising the steps of:

dividing design pattern data into pixel regions and calculating a ratio of the divided design pattern data to said pixel region;

generating a gray level bit map based on the ratio of said divided design pattern data;

dividing pattern data for an electron beam patterning system into said pixel regions and calculating a ratio of the divided pattern data for an electron beam patterning system to said pixel region;

generating a gray level bit map based on the ratio of said divided pattern data for an electron beam patterning system; and

making a comparison between a gray level bit map for said design pattern data and a gray level bit map for said pattern data for an electron beam patterning system to determine whether said pattern data for an electron beam patterning system matches said design pattern data.

15. A medium having a pattern comparison inspection program recorded thereon, comprising the steps of:

dividing pattern data for an electron beam patterning system into pixel regions and calculating a ratio of the divided pattern data for an electron beam patterning system to said pixel region;

generating a gray level bit map based on the ratio of said divided pattern data for an electron beam patterning system; and

detecting as multi-exposure a pixel region having a ratio of divided pattern data for an electron beam patterning system to the pixel region equal to or more than a predetermined value in a gray level bit map for said pattern data for an electron beam patterning system.

16. A pattern comparison inspection system comprising:

an occupancy calculating portion that divides pattern data into pixel regions and calculates a ratio of the divided pattern data to said pixel region;

a gray level bit map generating portion that generates a gray level bit map based on the ratio of said divided pattern data; and

a bit map comparing portion that makes a comparison between a gray level bit map for design pattern data and a gray level bit map for pattern data for an electron beam patterning system both generated by said occupancy calculating portion and said gray level bit map generating portion to determine whether said pattern data for an electron beam patterning system matches said design pattern data.

17. A pattern comparison inspection system comprising:

an occupancy calculating portion that divides pattern data into pixel regions and calculates a ratio of the divided pattern data to said pixel region;

a gray level bit map generating portion that generates a gray level bit map based on the ratio of said divided pattern data; and

a multi-exposure detecting portion that detects a multi-exposure pixel region having a ratio of divided pattern data to the pixel region equal to or larger than a predetermined value within a gray level bit map for pattern data for an electron beam patterning system generated by said occupancy calculating portion and said gray level bit map generating portion.