Patent US6268093B1 successfully refreshed from Google Patents.
US6268093B1
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US
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Method for reticle inspection using aerial imaging
Assignee: Applied Materials Inc
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Filing: 1999-10-13
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Granted: 2001-07-31
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Expires: 2019-10-13
Abstract
Abstract A reticle inspection system for inspecting reticles can be used as an incoming inspection tool, and as a periodic and pre-exposure inspection tool. Mask shops can use it as an inspection tool compatible to their customers, and as a printable error detection tool. The inventive system detects two kinds of defects: (1) line width errors in the printed image; (2) surface defects. The line width errors are detected on the die area. The detection is performed by acquiring the image of the reticle under the same optical conditions as the exposure conditions, (i.e. wavelength, numerical aperture, sigma, and illumination aperture type) and by comparing multiple dies to find errors in the line width. Surface defects are detected all over the reticle. The detection of surface defects is performed by acquiring transmission and dark-field reflection images of the reticle and using the combined information to detect particles, and other surface defects.
Inventors
- 👤 Boaz Kenan
- 👤 Yair Eran
- 👤 Avner Karpol
- 👤 Emanuel Elyasaf
- 👤 Ehud Tirosh
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 08:58
CPC Classifications
G; G03; G03F; G03F7/00; G03F7/70; G03F7/70058; G03F7/70091; G03F7/701; G03F1/00; G03F1/68; G03F1/82; G03F1/84; G03F7/70125; G03F7/70483; G03F7/70605; G03F7/70616; G03F7/70633
Claims Analysis
Total Claims: 35
Claim 1
Independent Claim
134 words
A method for inspecting a multiple die reticle that is used with an optical exposure system under a set of exposure conditions, said multiple die reticle including at least a first die and a second die, said method comprising: acquiring a plurality of aerial images of said reticle using a transmitted light, said plurality of aerial images being acquired within a process window of said exposure system and using said set of exposure conditions; said plurality of aerial images including a first plurality of aerial images of said first die and a second plurality of aerial images of said second die; and comparing said first plurality of aerial images of said first die and said second plurality of aerial images of said second die to detect variations in line width in said first die.
Claim 2
Independent Claim
134 words
A method for inspecting a multiple die reticle that is used with an optical exposure system under a set of exposure conditions, said multiple die reticle including at least a first die and a second die, said method comprising: acquiring a plurality of aerial images of said reticle using a transmitted light, said plurality of aerial images being acquired within a process window of said exposure system and using said set of exposure conditions; said plurality of aerial images including a first plurality of aerial images of said first die and a second plurality of aerial images of said second die; and comparing said first plurality of aerial images of said first die and said second plurality of aerial images of said second die to detect variations in line width in said first die.
Claim 3
Dependent Claim
35 words
The method of claim 1 , wherein prior to said comparison step, said aerial images of said first and said second dies are transformed to simulate a behavior of a exposure system and the photoresist.
Claim 4
Dependent Claim
32 words
The method of claim 1 , wherein said acquired aerial images of said reticle are magnified in relation to corresponding images created on photoresist by said optical exposure system using said reticle.
Claim 5
Dependent Claim
44 words
The method of claim 1 , wherein each of said first plurality of aerial images of said first die corresponds to a different focal condition; and each of said second plurality of aerial images of said second die corresponds to a different focal condition.
Claim 6
Dependent Claim
32 words
The method of claim 4 , wherein different focal conditions represented in said first and second pluralities of aerial images expands the focus dimension of the process window of the exposure system.
Claim 7
Dependent Claim
30 words
The method of claim 1 , wherein there are three aerial images in said first plurality of aerial images, and three aerial images in said second plurality of aerial images.
Claim 8
Dependent Claim
72 words
The method of claim 1 , wherein: a first aerial image of said first plurality of aerial images of said first die is in focus; a second aerial image of said first plurality of aerial images of said first die is out of focus in a positive direction; and a third aerial image of said first plurality of aerial images of said first die is out of focus in a negative direction.
Claim 9
Dependent Claim
72 words
The method of claim 7 , wherein: a first aerial image of said second plurality of aerial images of said second die is in focus; a second aerial image of said second plurality of aerial images of said second die is out of focus in a positive direction; and a third aerial image of said second plurality of aerial images of said second die is out of focus in a negative direction.
Claim 10
Dependent Claim
41 words
The method of claim 1 , further comprising: acquiring an image of said reticle using a reflected light; and using said acquired image of said reticle and said plurality of aerial images of said reticle to detect defects in said reticle.
Claim 11
Dependent Claim
22 words
The method of claim 9 , wherein said reflected light is produced by illuminating said reticle using a dark field illumination system.
Claim 12
Dependent Claim
17 words
The method of claim 1 , further comprising displaying results of said comparison in a graphic form.
Claim 13
Dependent Claim
28 words
The method of claim 1 , further comprising using results of said comparison to produce a map of said variations in said line width of said first die.
Claim 14
Dependent Claim
17 words
The method of claim 1 , wherein said transmitted light is provided using a pulsating light source.
Claim 15
Dependent Claim
15 words
The method of claim 13 , wherein said pulsating light source is a pulsating laser.
Claim 16
Dependent Claim
17 words
The method of claim 9 , wherein said reflected light is provided using a pulsating light source.
Claim 17
Dependent Claim
15 words
The method of claim 15 , wherein said pulsating light source is a pulsating laser.
Claim 18
Dependent Claim
29 words
The method of claim 1 , wherein said acquiring said plurality of aerial images comprises placing said reticle on a stage and moving said stage in a continuous manner.
Claim 19
Dependent Claim
29 words
The method of claim 13 , wherein said acquiring said plurality of aerial images comprises placing said reticle on a stage and moving said stage in a continuous manner.
Claim 20
Dependent Claim
29 words
The method of claim 15 , wherein said acquiring said plurality of aerial images comprises placing said reticle on a stage and moving said stage in a continuous manner.
Claim 21
Independent Claim
91 words
A method for inspecting a reticle that is used with an optical exposure system under a set of exposure conditions, said method comprising: acquiring a plurality of aerial images of said reticle using a transmitted light, said plurality of aerial images being acquired within a process window of said exposure system and using said set of exposure conditions; acquiring an image of said reticle using a reflected light; and using said acquired image of said reticle and said plurality of aerial images of said reticle to detect defects in said reticle.
Claim 22
Independent Claim
91 words
A method for inspecting a reticle that is used with an optical exposure system under a set of exposure conditions, said method comprising: acquiring a plurality of aerial images of said reticle using a transmitted light, said plurality of aerial images being acquired within a process window of said exposure system and using said set of exposure conditions; acquiring an image of said reticle using a reflected light; and using said acquired image of said reticle and said plurality of aerial images of said reticle to detect defects in said reticle.
Claim 23
Dependent Claim
31 words
The method of claim 20 , wherein said acquired images of said reticle are magnified in relation to corresponding images created on photoresist by said optical exposure system using said reticle.
Claim 24
Dependent Claim
23 words
The method of claim 20 , wherein each of said plurality of aerial images of said reticle corresponds to a different focal condition.
Claim 25
Dependent Claim
20 words
The method of claim 20 , wherein said transmitted and said reflected light are provided using a pulsating light source.
Claim 26
Dependent Claim
15 words
The method of claim 23 , wherein said pulsating light source is a pulsating laser.
Claim 27
Dependent Claim
29 words
The method of claim 20 , wherein said acquiring said plurality of aerial images comprises placing said reticle on a stage and moving said stage in a continuous manner.
Claim 28
Dependent Claim
29 words
The method of claim 23 , wherein said acquiring said plurality of aerial images comprises placing said reticle on a stage and moving said stage in a continuous manner.
Claim 29
Independent Claim
75 words
A method for determining a process window for exposure of a multiple die reticle by an optical exposure system, said reticle to be exposed by said optical exposure system under a set of exposure conditions, said method comprising steps of: acquiring a plurality of aerial images of said reticle using a transmitted light under said set of exposure conditions; and using said acquired aerial images to determine said process window of said optical exposure system.
Claim 30
Independent Claim
75 words
A method for determining a process window for exposure of a multiple die reticle by an optical exposure system, said reticle to be exposed by said optical exposure system under a set of exposure conditions, said method comprising steps of: acquiring a plurality of aerial images of said reticle using a transmitted light under said set of exposure conditions; and using said acquired aerial images to determine said process window of said optical exposure system.
Claim 31
Dependent Claim
63 words
The method of claim 27 , wherein: a first image of said plurality of aerial images of said reticle is in focus; a second image of said plurality of aerial images of said reticle is out of focus in a positive direction; and a third image of said plurality of aerial images of said reticle is out of focus in a negative direction.
Claim 32
Dependent Claim
28 words
The method of claim 27 , wherein said plurality of aerial images of said reticle and said image of said reticle are acquired using a pulsating light source.
Claim 33
Dependent Claim
15 words
The method of claim 29 , wherein said pulsating light source is a pulsating laser.
Claim 34
Dependent Claim
29 words
The method of claim 27 , wherein said acquiring said plurality of aerial images comprises placing said reticle on a stage and moving said stage in a continuous manner.
Claim 35
Dependent Claim
29 words
The method of claim 29 , wherein said acquiring said plurality of aerial images comprises placing said reticle on a stage and moving said stage in a continuous manner.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 2004-07-30 | 2005-01-29 | 2005-07-31 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2008-07-30 | 2009-01-29 | 2009-07-31 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2012-07-30 | 2013-01-29 | 2013-07-31 | $7700.00 | Window Closed / Lapsed |