Method and system for machine vision-based feature detection and mark verification in a workpiece or wafer marking system

• US RE41,924 E1
• Filed: 11/30/2007
• Issued: 11/16/2010
• Est. Priority Date: 05/17/2002
• Status: Expired due to Term

• Current Assignee: Electro Scientific Industries Incorporated (MKS Instruments Incorporated)
• Original Assignee: GSI Group Corporation (Novanta Inc.)
• Inventors: Woelki, Michael, Engineer, Amit V., Nemets, Christian
• Primary Examiner(s): LE, QUE TAN
• Application Number:
  US11/948,425
• Time in Patent Office: 1,082 Days
• Field of Search: 250/559.4, 250/559.3, 250/559.44, 250/548, 250/208.1, 356399-402, 355/53, 355/55
• US Class Current: 250/559.4
• CPC Class Codes: B23K 2101/007 Marks, e.g. trade marks
• CPC Class Codes: B23K 2101/40 Semiconductor devices
• CPC Class Codes: B23K 2103/50 Inorganic material, e.g. metals, not provided for in B23K2103/02 – B23K2103/26
• CPC Class Codes: B23K 26/04 Automatically aligning, aiming or focusing the laser beam, e.g. using the back-scattered light
• CPC Class Codes: B23K 26/042 Automatically aligning the laser beam
• CPC Class Codes: B23K 26/043 along the beam path, i.e. alignment of laser beam axis relative to laser beam apparatus
• CPC Class Codes: B23K 26/0853 Devices involving movement of the workpiece in at least in two axial directions, e.g. in a plane
• CPC Class Codes: B23K 26/361 for deburring or mechanical trimming B23K26/351 takes precedence
• CPC Class Codes: B23K 26/40 taking account of the properties of the material involved
• CPC Class Codes: B23K 26/705 Beam measuring device
• CPC Class Codes: G06K 1/126 by photographic or thermographic registration recording apparatus for measuring instruments G01D15/00
• CPC Class Codes: H01C 17/242 by laser trimming by laser in general B23K26/351
• CPC Class Codes: H01L 21/67282 Marking devices
• CPC Class Codes: H01L 21/681 using optical controlling means
• CPC Class Codes: H01L 2223/5442 comprising non digital, non alphanumeric information, e.g. symbols
• CPC Class Codes: H01L 2223/54453 for use prior to dicing
• CPC Class Codes: H01L 2223/54473 for use after dicing
• CPC Class Codes: H01L 2223/5448 Located on chip prior to dicing and remaining on chip 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 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A system and method for inspecting machine readable marks on one side of a wafer without requiring transmission of radiant energy from another side of the wafer and through the wafer. The wafer has articles which may include die, chip scale packages, circuit patterns and the like. The marking occurs in a wafer marking system and within a designated region relative to an article position. The articles have a pattern on a first side. The method includes the steps of imaging a first side of the wafer, imaging a second side of the wafer, establishing correspondence between a portion of first side image and a portion of a second side image, and superimposing image data from the first and second sides to determine at least the position of a mark relative to an article.

Claims

1. A method for inspecting machine readable marks on one side of a wafer without requiring transmission of radiant energy from another side of the wafer and through the wafer, the wafer having articles which may include die, chip scale packages, circuit patterns and the like, the marking occuring in a wafer marking system and within a designated region relative to an article position, the articles having a pattern on a first side, the method comprising:

imaging a first side of the wafer;

imaging a second side of the wafer;

establishing correspondence between a portion of first side image and a portion of a second side image; and

superimposing image data from the first and second sides to determine at least the position of a mark relative to an article.

2. The method of claim 1 further comprising substantially matching images obtained from the first and second sides so that the superimposed image portions correspond, wherein the step of substantially matching is carried out using a calibration target and a matching algorithm.

3. The method of claim 2 wherein the superimposed data is used to determine the position of a mark relative to the article.

4. A system for inspecting machine readable marks on one side of a wafer without requiring transmission of radiant energy from another side of the wafer and through the wafer, the wafer having articles which may include die, chip scale packages, circuit patterns and the like, the marking occurring in a wafer marking system and within a designated region relative to an article position, the articles having a pattern on a first side, the system comprising:

means for imaging the first side of the wafer to obtain an image;

means for imaging a mark on the second side of the wafer to obtain an image;

means for establishing correspondence between a portion of a first side image and a portion of a second side image; and

means for superimposing image data from the first and second sides to determine at least the position of the mark relative to an article.

5. The system as claimed in claim 4 wherein the means for establishing correspondence includes a calibration target and an algorithm.