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

• US 20070031993A1
• Filed: 10/09/2006
• Published: 02/08/2007
• Est. Priority Date: 05/17/2002
• Status: Abandoned Application

• Current Assignee: Electro Scientific Industries Incorporated (MKS Instruments Incorporated)
• Original Assignee: GSI Lumonics Corporation (Novanta Inc.)
• Inventors: Woelki, Michael, Nemets, Chris, Pukmel, Michael
• Application Number:
  US11/544,898
• Publication Number:
  US 20070031993A1
• Time in Patent Office: Days
• US Class Current: 438/110
• 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 2924/00 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 precision laser based method of marking semiconductor wafers, packages, substrates or similar workpieces is provided. The workpieces have articles which may include die, chip scale packages, circuit patterns and the like. The marking occurs in a workpiece marking system and within a designated region relative to an article position. The method includes determining at least one location from which reference data is to be obtained using (a) information from which a location of an article is defined, and (b) a vision model of at least a portion of at least one article. Reference data is obtained to locate a feature on a first side of (a second) workpiece using at least one signal from a first sensor. The method further includes positioning a marking field relative to the workpiece so as to position a laser beam at a marking location on a second side of the workpiece. The positioning is based on the feature location. A predetermined pattern is marked on the second side of the workpiece using a laser marking output beam. The workpiece is a semiconductor wafer, and the step of determining includes: measuring at least one feature in an image obtained from a first wafer portion; relating the measured feature to a wafer map; and storing the data for use when marking of wafers substantially identical to the first wafer.

Claims

1-15. -15. (canceled)

16. In a laser based system for laser marking of substrates such as semiconductor wafers or similar substrates with a laser marking beam, the substrates having a repetitive pattern of articles arranged in rows and columns, each of the articles having a feature detectable with an imaging subsystem, the system having a laser marking head, the imaging subsystem for imaging and measurement, a motion subsystem having a stage for positioning at least the substrate relative to the imaging subsystem, and a user interface connected at least to the imaging subsystem and motion subsystem, wherein laser marks are to be placed at predetermined locations relative to the articles, a method of laser marking with beam position control using predetermined pattern features, the method comprising:

providing, through the user interface, an input so as to cause a portion of the pattern to be identified for automatic feature detection and measurement with a machine vision algorithm;

positioning a first substrate relative to the imaging subsystem automatically to traverse the pattern along at least one of a row or column of the pattern so as to acquire image data at a first set of feature locations;

measuring a dimension using at least one detectable feature of a plurality of articles, the algorithm, and the image data;

storing dimensional data based on the measurement;

determining at least three feature locations of a second set of feature locations relative to the pattern using the dimensional data, the feature locations of the second set suitably defining a relationship between a pattern coordinate system and a stage coordinate system;

removing the first substrate;

positioning a second substrate to be marked relative to the imaging subsystem;

locating the at least three corresponding feature locations of the second set of feature locations in image data obtained from the corresponding pattern on the second substrate;

relating coordinates of the pattern on the first substrate to the corresponding pattern on the second substrate; and

positioning the substrate relative to the marking beam based on at least the three feature locations of the second set to mark the substrate.

17. The method of claim 16 wherein a first estimate of the dimension is obtained by semiautomatic relative positioning of the substrate and the imaging subsystem over a substantially small area of the pattern and further comprising:

identifying a feature in a displayed image; and

communicating the image location of the feature using the user interface.

18. The method of claim 17 wherein the substrate is a semiconductor wafer, the articles are die, and a feature is a corner of the die.

19. The method of claim 18 wherein the dimensional measurement is the average die pitch measured over a substantial number of die along at least one of a row and column.

20. The method of claim 19 wherein the average die pitch is related with a wafer map.

21. The method of claim 16 wherein the pattern coordinate system has an origin defined relative to a boundary of the pattern.

22. The method of claim 16 wherein the step of determining includes searching for pattern locations, and wherein searching is carried out controlling the stage based on pattern system coordinates.

23. The method of claim 16 wherein the step of providing further includes generating a vision model using an image of a portion of the pattern.

24. A system for carrying out the method of claim 16.