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System and Method for Inspecting Electrical Circuit Patterns for Deformations

IP.com Disclosure Number: IPCOM000011998D
Publication Date: 2003-Apr-01

Publishing Venue

The IP.com Prior Art Database

Related People

Nissim SAVAREIGO: INVENTOR [+2]

Abstract

A system and method for inspecting electrical circuits which, in response to analyzing an image of a portion of an electrical circuit, provide an inspection output indicating a shape change or shape deformation in the portion.

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[339.1.5.02]

SYSTEM AND METHOD FOR INSPECTING ELECTRICAL
CIRCUIT PATTERNS FOR DEFORMATIONS

FIELD OF THE INVENTION

[0001] The present invention relates to systems and methods
useful for inspecting electrical circuit patterns for defects,
and more particularly to systems and methods employed in the
automated optical inspection of electrical circuits.

BACKGROUND OF THE INVENTION

[0002] Electrical circuits, such as printed circuit boards,
typically include one or more substrate layers, each layer
containing a portion of an electrical circuit. Conventional
methodologies for applying electrical circuit portions to a
substrate employ photolithography.

[0003] Printed circuit board substrate layers typically are
inspected during manufacture using automated optical inspection
devices. Automated optical inspection is used to ensure, inter
alia
that all parts of the electrical circuit are present, that
all parts of the electrical circuit are located acceptably close
to a desired location, and that undesired formations are not
present.

1

[0004] During the fabrication of a portion of an electrical
circuit on a substrate layer, for example by way of
photolithography, a substrate layer on which an electrical
circuit portion is deposited may stretch thereby changing or
deforming the shape of the electrical circuit portion.
Additionally, process equipment used to form the portion of an
electrical circuit, such as equipment employed in the
photolithography process, may not be fully aligned. Any
misalignment in the process equipment, including for example
optical alignment or adjustment of chemical processes, may also
result in a change or deformation in the shape of the portion of

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an electrical circuit. Stretching, shape change or deformation
can negatively affect the electrical circuit manufacture
process.

SUMMARY OF INVENTION

[0005] The present invention seeks to provide systems and
methods for inspecting electrical circuits which, in response to
analyzing an image of a portion of an electrical circuit,
provide an inspection output indicating a stretching or shape
deformation of a portion of an electrical circuit pattern.

[0006] One general aspect of the invention relates to systems
and methods that are operative to determine an actual location
of at least some parts of an electrical circuit being inspected
relative to a desired location of those parts. Such a
determination may be, for example, part of an inspection output
which indicates an actual difference in location for selected
parts, for example conductor pads, of the electrical circuit
portion. Alternatively the determination may be part of an
inspection output that provides a generalized indication of
differences in location, based on, for example, a statistical or
other suitable analysis, at selected regions in an electrical
circuit portion. In accordance with an embodiment of the
invention, the output indicates a stretching or shape
deformation in the portion of an electri...