System for detecting position of pattern

• US 3,898,617 A
• Filed: 02/22/1974
• Issued: 08/05/1975
• Est. Priority Date: 02/22/1973
• Status: Expired due to Term

• Current Assignee: Masakazu Ejiri, Seiji Kashioka
• Original Assignee: Masakazu Ejiri, Seiji Kashioka
• Inventors: Kashioka, Seiji, Ejiri, Masakazu
• Primary Examiner(s): Boudreau, Leo H.
• Application Number:
  US05/444,858
• Time in Patent Office: 529 Days
• Field of Search: 340/146.3H,146.3AH,146.3Q,146.3E,146.3AC
• US Class Current: 382/151
• CPC Class Codes: G06V 10/20 Image preprocessing
• CPC Class Codes: G06V 10/24 Aligning, centring, orientation detection or correction of the image
• CPC Class Codes: G06V 10/40 Extraction of image or video features
• CPC Class Codes: G06V 10/443 by matching or filtering
• CPC Class Codes: H01L 21/00 Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
• CPC Class Codes: H01L 2223/54473 for use after dicing
• CPC Class Codes: H01L 23/544 Marks applied to semiconductor devices or parts, e.g. registration marks, alignment structures, wafer maps test patterns for characterising or monitoring manufacturing processes H01L22/00
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A system for detecting the position of a pattern, wherein a specific partial pattern in a pattern of an object is previously stored as a standard pattern, two-dimensional partial patterns are sequentially set out from the pattern of the object picked up by an image pickup device, the partial patterns set out are successively compared with the standard pattern to thus detect degrees of coincidence, and coordinates of a position to be found on the pattern of the object are calculated from the coordinates of a position representing the most coincident partial pattern.

Claims

1. A system for detecting the position of a pattern comprising:

image pickup means for sequentially scanning an image of an object to produce first signals representative thereof;

memory means for storing signals representative of a twodimensional standard pattern which corresponds to a selected portion of a two-dimensional pattern of the object;

first means, responsive to said first signals, for generating second signals representative of sequential portions of a twodimensional pattern of said object as sequentially scanned by said image pickup means;

second means, responsive to the scan of said object by said image pickup means, for generating third signals representative of the respective sequential positions of said sequentially scanned two-dimensional pattern portions;

third means, coupled to said memory means and said first means, for comparing the signals stored in said memory means with said second signals, to thereby detect which of said sequentially scanned two-dimensional pattern portions has the greates degree of coincidence with said standard pattern; and

fourth means, coupled to said second and third means for calculating the coordinates of a specific position within the two-dimensional pattern of said object on the basis of the coordinates of the position of that pattern portion having the greatest degree of coincidence with said standard pattern.

2. A system according to claim 1, further including means, coupled between said image pickup means and said first means, for converting images received by said image pickup means into binary signals, whereby said third means compares each bit making up the signals stored in said first memory and said binary signals, to detect the degree of coincidence therebetween.

3. A system according to claim 2, wherein said binary signal converting means includes means for storing signals representative of a two-dimensional pattern of that frame immediately preceding the frame which is being scanned by said image pickup means, means for generating a signal representative of the average brightness of the two-dimensional pattern of the preceding frame, and means for converting image information of the frame being scanned into binary signals in dependence upon a threshold value corresponding to said average brigtness signal.

4. A system according to claim 3, wherein said means for connecting image information comprises a threshold circuit and a plurality of sequentially arranged shift registers connected thereto for generating and storing binary signals respectively corresponding to picture elements for a respective plurality of sequential horizontal scans.

5. A system according to claim 1, wherein said memory means contains a plurality of memory storage locations for storing therein at least two specific patterns within said two-dimensional pattern of said object as respective standard patterns, and wherein said third means comprises means to detect which sequentially scanned pattern portion has the greates degree of coincidence with one of said stored standard patterns, and means to detect which sequentially scanned pattern portion has the greatest degree of coincidence with another of said stored standard patterns, so that the coordinates of a specific position within said two-dimensional pattern are calculated on the basis of the coordinates of positions representing both sequentially scanned pattern portions.

6. A system according to claim 5, wherein said fourth means includes means for comparing the degrees of coincidence between the pattern portions having the highest degrees of coincidence and for detecting the coordinates of a representative position of that pattern portion which has the maximum degree of coincidence, so that the coordinates of said specific position within said two-dimensional pattern are calculated on the basis of the detected coordinates of said representative position.

7. A system according to claim 5, further comprising respective switching means, coupled to said memory means and said third means, for commutating the respective comparisons between said standard patterns and said sequentially scanned pattern portions for the respective sequential scanning periods or scanning areas of said object by said image pickup means.

8. A system according to clAim 5, wherein said fourth means includes means for effecting an angular correction for said two-dimensional pattern in accordance with the coordinate of the representative positions of a scanned pattern portion having a high degree of coincidence.

9. A system according to claim 1, further comprising object marking means including a half-mirror and a first shutter disposed between said image pickup means and said object, a light source for illuminating said object through said half-mirror and said first shutter, a reference plate having a prescribed mark formed thereon on which light from said light source impinges through said half-mirror, and a second shutter disposed between said half-mirror and said reference plate, so that the pattern of said object and the prescribed mark on said reference plate can be selectively received by said image pickup means.

10. A system according to claim 1, wherein said object is a semiconductor element.

11. A system according to claim 1, wherein said object has a concentrically shaped pattern formed thereon for selective detection thereof.

12. A system according to claim 1, wherein said image pickup means includes a plurality of image pickup devices and means coupled between said image pickup devices and said first means for selectively switching the first signals provided by said pickup devices to said first means.

13. A system according to claim 4, wherein said third means comprises a plurality of '"'"''"'"''"'"''"'"'EXCLUSIVE OR'"'"''"'"''"'"''"'"' logic circuits coupled to the respective bit positions of said shift registers and to the memory bit positions of said first memory means, for respectively determining bit-coincidence between the respective bit positions being compared, a summing circuit for providing an output signal representative of the sum of the outputs of said '"'"''"'"''"'"''"'"'EXCLUSIVE OR'"'"''"'"''"'"''"'"' circuits and means for comparing the output of said summing circuit with a signal representative of the degree of coincidence of a previously scanned pattern portion with a standard pattern, and for generating an output signal only when said degree of coincidence representative signal exceeds a threshold value.

14. A system according to claim 13, further including means coupled between said second means and said fourth means, and responsive to the output signal generated by the comparing means of said third means, for gating said third signals to said fourth means.

15. In a system for assembling a plurality of articles, especially semiconductor elements, including automatic machines for effecting selective bonding of the articles, an improved sub-system for detecting the position of a pattern correponding to a respective one of said articles to be assembled, said improved sub-system comprising:

a plurality of image pickup devices each of which is disposed to sequentially scan an image of an article to produce first signals representative of a pattern defined by said article;

memory means for storing signals respresentative of a two-dimensional standard pattern which corresponds to a selected portion of a two-dimensional pattern of the object;

first means, responsive to said first signals, for generating second signals representative of sequential portions of a two-dimensional pattern of said article as sequentially scanned by said image pickup device;

second means, responsive to the scan of said article by said image pickup device, for generating third signals representative of the respective sequential positions of said sequentially scanned two-dimensional pattern portions;

third means, coupled to said memory means and said first means, for comparing the signals stored in said memory means with said second signals, to thereby detect which of said sequentially scanned two-dimensional pattern portions has the greates degree of coincidence with said standard pattern;

fourth means, coupled to said second and third means, for calculating the coordinates of a specific position within the two-dimensionAl pattern of said article on the basis of the coordinates of the position of that pattern portion having the greatest degree of coincidence with said standard pattern;

fifth means, coupled between each image pickup device and said first means, for selectively switching the outputs of the respective ones of said image pickup devices to said first means, for selective coordinate position calculation of each respective article; and

sixth means, coupled between said fourth means and said automatic bonding machines, for positioning the respective ones of said bonding machines relative to the respective ones of said articles in accordance with the coordinate calculation outputs of said fourth means.