Mask inspecting method and mask detector

• US 5,481,624 A
• Filed: 04/13/1993
• Issued: 01/02/1996
• Est. Priority Date: 04/27/1992
• Status: Expired due to Term

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Kamon, Kazuya
• Primary Examiner(s): NOT, DEFINED
• Assistant Examiner(s): Chang, Jon
• Application Number:
  US08/045,471
• Time in Patent Office: 994 Days
• Field of Search: 382/8, 382/144, 358/101, 356/237, 356/394, 348/87, 355/53, 250/492.2
• US Class Current: 382/144
• CPC Class Codes: G03F 1/26 Phase shift masks [PSM]; PSM blanks; Preparation thereof
• CPC Class Codes: G03F 1/84 Inspecting
• CPC Class Codes: G03F 7/70283 Mask effects on the imaging process
• CPC Class Codes: G03F 7/70433 Layout for increasing efficiency or for compensating imaging errors, e.g. layout of exposure fields for reducing focus errors; Use of mask features for increasing efficiency or for compensating imaging errors
• CPC Class Codes: H01J 2237/2817 Pattern inspection

Abstract

A mask inspecting method for inspecting defects of a phase-shifting mask comprises the steps of converting pattern data of a designed circuit pattern to pattern data for a phase-shifting mask, manufacturing a phase-shifting mask as a function of the pattern data for a phase-shifting mask, detecting the phase-shifting mask using the same optical conditions as that of the exposure step in the process of manufacturing a semiconductor device which makes use of the phase shift method to obtain image data thereof and checking the image data with the pattern data of the designed circuit pattern. In the method, image data of the pattern data identical to a pattern transferred onto a semiconductor substrate can be obtained, so that it is possible to check the above pattern data with the pattern data of the circuit pattern. Thus, the inspection of the phase-shifting mask can be accomplished.

Claims

1. A method of inspecting a phase-shifting mask used in an exposure step of a process of manufacturing a semiconductor device, comprising the steps of:

(a) producing first pattern data as a function of a given circuit pattern;

(b) converting said first pattern data into second pattern data used for manufacturing a phase-shifting mask;

(c) manufacturing said phase-shifting mask as a function of said second pattern data;

(d) detecting a pattern of said phase-shifting mask using optical conditions related with those of said exposure step which makes use of a phase shift method to obtain image data; and

(e) checking said image data with said first pattern data;

wherein said step of detecting a pattern of said phase-shifting mask is performed using a mask detector and comprises;

projecting single-wavelength light using a light source;

introducing said light from said light source onto a mask surface of said phase-shifting mask using a first optical system;

forming an optical image of said light which passes through said phase-shifting mask using a second optical system;

imaging said optical image of said phase-shifting mask to obtain image data using an imaging means; and

setting said mask detector to satisfy the following relations,

space="preserve" listing-type="equation">λ

1=λ

space="preserve" listing-type="equation">σ

1=σ

space="preserve" listing-type="equation">m1·

A1=m·

A

space="preserve" listing-type="equation">m1>

m

where A1 and m1 represent a numerical aperture and a magnification of said mask detector, λ

1 and σ

1 represent a wavelength and a coherence of said light projected from said light source respectively, while A and m represent a numerical aperture and a magnification of said exposure device used in a process of manufacturing a semiconductor device, λ and

σ

represent a wavelength and a coherence of light used therein;

said method further comprising inspecting with an enlarged pattern based on

space="preserve" listing-type="equation">R1=(m1/m)·

R;

where R1 and R represent minimum resolving powers of said mask detector and said exposure device used in a process of manufacturing a semiconductor device, respectively.

2. A method of inspecting a mask of claim 1, wherein said first pattern data are produced by using CAD.

3. A method of inspecting a mask of claim 1, wherein said method further comprises the steps of:

imaging said pattern of said phase-shifting mask by an imaging means which does not produce a phase shift to obtain image data; and

checking said image data with said second pattern data.

4. A mask detector having a minimum resolving power R1, comprising:

a light source for projecting single-wavelength light;

a first optical system for introducing said light projected from said light source onto a mask surface of a phase-shifting mask;

a second optical system for forming an optical image of said light which passes through said phase-shifting mask; and

an imaging means for imaging said optical image of said phase-shifting mask to obtain image data; and

wherein

said mask detector is set to satisfy the following relations,

space="preserve" listing-type="equation">λ

1=λ

space="preserve" listing-type="equation">σ

1=σ

space="preserve" listing-type="equation">m1·

A1=m·

A

space="preserve" listing-type="equation">m1>

m

where A1 and m1 represent a numerical aperture and a magnification of said mask detector, λ

1 and δ

1 represent a wavelength and a coherence of said light projected from said light source respectively, while A and m represent a numerical aperture and a magnification of an exposure device having a minimum resolving power R and used in a process of manufacturing a semiconductor device using said phase-shifting mask, λ and

δ

represent a wavelength and coherence of light used therein; and

R1=(m1/m)·

R.

5. A method of inspecting a phase-shifting mask used in an exposure step of a process of manufacturing a semiconductor device, comprising the steps of:

(a) producing first pattern data as a function of a given circuit pattern;

(b) converting said first pattern data into second pattern data used for manufacturing a phase-shifting mask;

(c) manufacturing said phase-shifting mask as a function of said second pattern data;

(d) exposing said phase-shifting mask using optical conditions related to those of said exposure step which makes use of a phase shift method to obtain a pattern for inspection;

(e) imaging said pattern for inspection to obtain image data; and

(f) checking said image data with said first pattern data;

wherein said step of transferring said phase-shifting mask is performed using a mask exposure device and comprises;

projecting single-wavelength light using a light source;

introducing said light from said light source onto a mask surface of said phase-shifting mask using a first optical system;

condensing light which passes through said phase-shifting mask onto a resist surface of said masking material using a second optical system; and

setting said mask exposure device to satisfy the following relations,

space="preserve" listing-type="equation">λ

2=λ

space="preserve" listing-type="equation">σ

2=σ

space="preserve" listing-type="equation">m2·

A2=m·

A

space="preserve" listing-type="equation">m2>

m

where A2 and m2 represent a numerical aperture and a magnification of said mask exposure device, λ

2 and σ

2 represent a wavelength and a coherence of said light projected from said light source respectively, while A and m represent a numerical aperture and a magnification of said exposure device used in a process of manufacturing a semiconductor device, λ and

σ

represent a wavelength and a coherence of light used therein; and

said method further comprises inspecting with an enlarged pattern based on

space="preserve" listing-type="equation">R2=(m2/m)·

R;

where R2 and R represent minimum resolving powers of said mask exposure device and said exposure device used in a process of manufacturing a semiconductor device, respectively.

6. A method of inspecting a mask of claim 5, wherein said first pattern data are produced by using CAD.

7. A method of inspecting a mask of claim 5, wherein said method further comprises the steps of:

imaging said pattern of said phase-shifting mask by an imaging means which does not produce a phase shift to obtain image data; and

checking said image data with said second pattern data.