Automatic X-ray determination of solder joint and view Delta Z values from a laser mapped reference surface for circuit board inspection using X-ray laminography
AssigneeAgilent Technologies, Inc.
InventorPaul A. Roder
Life of this patent
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Abstract
An improved circuit board inspection system incorporates self learning techniques for accurate determination of Z-axis elevations of electrical connections. A Delta Z, referenced to a laser range finder generated surface map of the circuit board, is automatically determined from a series of cross sectional images of the electrical connections for each electrical connection on the circuit board. The Delta Z values for each electrical connection are stored in a data base from which customized Delta Z values for specifically defined board views may be calculated.
Claims8
A device for inspecting electrical connections on a circuit board comprising:
- a processor which controls the acquisition of a cross-sectional image of a cutting plane of the electrical connection at an image plane and analyzes said cross-sectional image, said processor configured to implement the following:
- a Z-axis controller for varying a Delta Z value, i.e., the Z-axis distance between the image plane and a reference Z-axis position, and acquiring a plurality of Delta Z images of the electrical connection at a plurality of said Delta Z values;
- an image gradient section which calculates and stores a plurality of gradients for each of said plurality of Delta Z images;
- a variance calculator section which determines a variance of said plurality of gradients for each of said plurality of Delta Z images;
- and
- a comparator which compares said variances of said gradients for each of said plurality of Delta Z images.
Dependencies are inferred from the claim text.