Method and apparatus for detecting shorts in a multi-layer electronic package
First Claim
1. A method for locating shorts in multi-layer electronic packages during manufacture, comprising steps of:
- fitting a multi-layer package in a fixture, after forming a thin film layer of metalization on a top surface of the package;
detecting a short in the top surface of the package;
injecting a first test signal into a set of pins on a bottom surface of the package;
detecting a magnetic field produced by a short on the top surface when said first test signal is applied to said set of pins, the short being at least one of a short between planes of the package and an I/O-to-plane short of the package;
determining an approximate two-dimensional location of the short on the top surface based on a location of said magnetic field as detected in said detecting step; and
inspecting the top surface at the approximate location of the short to determine a location of the short within said approximate location.
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Accused Products
Abstract
A method and apparatus for locating shorts in multi-layer electronic packages during manufacture allows repair of the shorts and improved yields of the packages. A multi-layer package is fitted in a fixture after forming a thin film layer of metalization, and test is performed to detect shorts in the package. If a short is detected, a low current, high frequency signal is injected in pins on a bottom surface of the package. An approximate two dimensional location of the short is sensed by detecting an electromagnetic force induced by a magnetic field inductively coupled to a sensor proximate to the short on a top surface of the multi-layer package. The approximate location of the short is then inspected to precisely locate the short.
51 Citations
31 Claims
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1. A method for locating shorts in multi-layer electronic packages during manufacture, comprising steps of:
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fitting a multi-layer package in a fixture, after forming a thin film layer of metalization on a top surface of the package; detecting a short in the top surface of the package; injecting a first test signal into a set of pins on a bottom surface of the package; detecting a magnetic field produced by a short on the top surface when said first test signal is applied to said set of pins, the short being at least one of a short between planes of the package and an I/O-to-plane short of the package; determining an approximate two-dimensional location of the short on the top surface based on a location of said magnetic field as detected in said detecting step; and inspecting the top surface at the approximate location of the short to determine a location of the short within said approximate location. - View Dependent Claims (13, 14, 15, 16, 17)
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2. The method recited in claim I wherein the step of detecting said magnetic field comprises steps of moving an iron core inductor across the top surface of the multi-layer package, and detecting induced in the iron core inductor by said magnetic field, and
wherein said method further comprises a step of providing an output signal indicative of the approximate location of the short.
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18. An apparatus for locating shorts in multi-layer electronic packages during manufacture comprising:
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a fixture for receiving a multi-layer package after a thin film layer of metalization had been formed on a top surface of the package; a set of pins on a bottom surface of the package; a reference signal generating circuit which applies a first test signal to said set of pins; and a sensor movable in a plane parallel to the top surface of the package for detecting a magnetic field produced by a short on the top surface when said first test signal is applied to said set of pins, the short being at least one of a short between planes of the package and an I/O-to-plane short of the package; wherein a location of said magnetic field relative to the top surface corresponds to an approximate two-dimensional location of the short. - View Dependent Claims (19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31)
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Specification