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 Title: |
US5388517:
Method and apparatus for automatic alignment of objects and register mark for use therewith
[ Derwent Title ]
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| Country: |
US United States of America
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| Inventor: |
Levien, Raphael L.; McDowell, VA 24458
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| Assignee: |
None
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| Published / Filed: |
1995-02-14
/ 1993-09-20
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| Application Number: |
US1993000123871
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| IPC Code: |
Advanced:
B41F 33/14;
G03F 7/20;
G03F 9/00;
H01L 21/027;
H01L 21/30;
Core:
more...
IPC-7:
B41F 13/12;
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| ECLA Code: |
G03F7/20T22; G03F9/00; G03F9/00T;
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| U.S. Class: |
Current:
101/485;
101/211;
Original:
101/485;
101/211;
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| Field of Search: |
101/181,248,485,486,211,170,171,481
250/491.1,398,492.2
358/454
356/363,401,374
226/002,3,27,28,24
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| Priority Number: |
| 1993-09-20 |
US1993000123871 |
| 1991-09-24 |
US1991000764647 |
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| Abstract: |
A register mark and a system for bringing a pair of register marks into alignment is disclosed. A first register mark comprises a plurality of dots of a first frequency, and a second register mark comprises a plurality of dots of a second, generally higher frequency. When the first and second register marks are overlaid, an interference pattern resulting from the difference in frequency is observed. The first and second register marks are in alignment when the interference pattern produces a maximum bright spot in the center of the register mark. A small relative movement of the first and second register marks results in a larger relative movement of center of the bright spot. The position of the bright spot indicates which direction and how much to move the second register mark in order to achieve image registration. In an alternate embodiment of the present invention, the frequency of dots in each register mark is warped with distance from the center of the mark. The frequency of the dots of the second register mark is also warped with distance from the center, but overall has a generally higher frequency of dots as compared to the first register mark. The interference pattern resulting from an overlay of the latter two register marks results in a bright spot which occurs unambiguously when the two register marks are in alignment. At misalignments of more than one dot width, the bright spot breaks up so that the overlaid register marks may serve as quick visual check of proper alignment.
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| Attorney, Agent or Firm: |
Jacobson, Allan ;
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| Primary / Asst. Examiners: |
Fisher, J. Reed;
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| Maintenance Status: |
E2 Expired Check current status
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| INPADOC Legal Status: |
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Family Legal Status Report
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| Parent Case: |
This is a continuation of application Ser. No. 764,647, filed Sep. 24, 1991, now abandoned.
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| Designated Country: |
DE FR GB
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| Family: |
Show 9 known family members
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First Claim:
Show all 48 claims |
What is claimed is:
1. A method for aligning first and second objects, wherein said first and second objects are coupled to respective first and second register marks, said first register mark including a first plurality of dots at a first frequency and said second register mark including a second plurality of dots at a second frequency, said method comprising:
- providing said first register mark including a first plurality of dots at a first frequency arranged in a two dimensional array wherein the frequency of dots in said first register mark is maximum at the center and decreases with radial distance in substantially all directions from the center of said first register mark; and
- providing said second register mark including a second plurality of dots at a second frequency arranged in two dimensional array wherein the frequency of dots in said second register mark is maximum at the center and decreases with radial distance in substantially all directions from the center of said second register mark, said frequency of dots in said second register mark being greater than said frequency of said dots in said first register mark at corresponding points of said first and second register marks respectively;
- positioning at least one of said first and second objects so that said second register mark is disposed in overlaid relation to said first register mark, thereby producing a bright spot providing a peak indication having a maximum point substantially common to said first and second overlaid register marks indicative of the registration of said first and second register marks;
- detecting the position of said bright spot providing a peak indication as said maximum point derived from a set of data points; and
- moving said one of said first and second objects to reposition said bright spot providing a peak indication towards the center of said one of said first and second register marks.
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| Background / Summary: |
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| Drawing Descriptions: |
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| Description: |
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| Forward References: |
Show 23 U.S. patent(s) that reference this one
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