Ball grid array (BGA) package on-line non-contact inspection method and system
First Claim
1. A system for the on-line inspection of the surface of objects including ball grid arrays, comprising:
- a grating, disposed near the object, for forming a shadow moiré
fringe pattern;
means for imaging the object;
means for generating light from at least three light sources disposed along a line at predetermined angles θ
1, θ
2, θ
3, which are defined by the locations of each of the light sources, the object and the means for imaging the object, wherein the illumination from the light sources is caused to individually flash in turn and is directed through the grating and onto the surface of the object; and
means for processing the images of the object to determine a measurement related to the surface of the object.
1 Assignment
0 Petitions
Accused Products
Abstract
A method and apparatus is disclosed for non-contact, on-line inspection of objects including a ball grid array package by means of a shadow moiré technique combined with a novel flash phase-shifting method. The grid pitch size, ball height, ball diameter, missing ball, coplananity can be determined or measured within several seconds. The apparatus includes a camera for viewing the object, a plurality of light sources arranged in a line for illuminating the object to be inspected, a frame grabber for capturing images of the object, an I/O adapter card for controlling the light sources and a personal computer for data processing. The individual components are integrated into system which provides a three dimensional map which is obtained quantitatively using a novel algorithm. The system can provide coplananity data, as well as data relating to grid pitch, ball height, ball diameter, and missing ball information.
45 Citations
14 Claims
-
1. A system for the on-line inspection of the surface of objects including ball grid arrays, comprising:
-
a grating, disposed near the object, for forming a shadow moiré
fringe pattern;
means for imaging the object;
means for generating light from at least three light sources disposed along a line at predetermined angles θ
1, θ
2, θ
3, which are defined by the locations of each of the light sources, the object and the means for imaging the object, wherein the illumination from the light sources is caused to individually flash in turn and is directed through the grating and onto the surface of the object; and
means for processing the images of the object to determine a measurement related to the surface of the object. - View Dependent Claims (2, 3, 4, 5, 6, 7)
-
-
8. A method for the on-line inspection of the surface of objects including ball grid arrays, comprising the steps of:
-
generating light from at least three light sources disposed along a line at predetermined angles θ
1, θ
2, θ
3, which are defined by the locations of each of the light sources, the object and means for imaging the object, wherein the illumination from the light sources is caused to individually flash in turn and is directed onto the surface of the object;
forming a fringe pattern;
imaging the fringe pattern when the object is illuminated by the light sources; and
processing the images to determine a measurement related to the surface of the object. - View Dependent Claims (9, 10, 11, 12, 13, 14)
-
Specification
-
- Resources
-
Current AssigneeNanyang Technological University
-
Original AssigneeNanyang Technological University
-
InventorsHua, Fan, Ngoi, Bryan Kok Ann
-
Primary Examiner(s)Allen, Stephone B.
-
Assistant Examiner(s)SPEARS, ERIC J
-
Application NumberUS09/452,160Time in Patent Office1,182 DaysField of Search250/559.34, 250/237.G, 250/559.45, 250/559.46, 356/237.4, 356/237.2, 356/237.5, 356/605, 356/618, 356/616, 382/145, 382/147, 382/148, 382/149, 382/150US Class Current250/559.34CPC Class CodesG01N 21/8806 Specially adapted optical a...
