System for measuring and detecting printed circuit wiring defects
First Claim
1. A non-contact system for detecting printed circuit wiring defects and for measuring circuit feature height relative to a substrate comprising:
- (a) a laser for illuminating said substrate and circuit features thereon;
(b) a charge coupled device (CCD) having a plurality of elements disposed therein for receiving laser energy reflected from a predetermined area on said substrate and circuit features thereon and wherein said plurality of CCD elements are individually and simultaneously activated, said CCD being disposed proximate said substrate and circuit features thereon and operatively related thereto, said CCD being capable of;
(i) substantially instantaneously receiving laser energy reflected from said substrate and cirucit features thereon; and
(ii) generating a signal in response thereto, said signal varying with the intensity of said reflected laser energy; and
(c) automatic analyzing means operatively connected to said CCD for correlating said signal received therefrom to a measurement representative of height of said cirucit features on said substrate and relative thereto, said analyzing means being adapted to analyze laser energy received by each of said plurality of CCD elements for a predetermined number of cycles so that non-linearities on said substrate and circuit features thereon are detected.
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Accused Products
Abstract
A non-contact system for detecting printed circuit wiring defects and for measuring circuit feature height relative to a substrate. The system has an energy source for illuminating the substrate and circuit features and a scanner for both instantaneously receiving energy reflected from the substrate and circuit features and for generating a signal in response to the reflected energy, which signal is adapted to vary with the intensity of the reflected energy. An analyzer is connected to the scanner for correlating the generated signal to a measurement representative of the height of the circuit features relative to the substrate. Variations and non-uniformity of the substrate surface due to bending, warpage or other causes can be accounted for so as to provide an accurate measurement of the height of a circuit feature relative to the substrate surface on which it is mounted.
95 Citations
19 Claims
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1. A non-contact system for detecting printed circuit wiring defects and for measuring circuit feature height relative to a substrate comprising:
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(a) a laser for illuminating said substrate and circuit features thereon; (b) a charge coupled device (CCD) having a plurality of elements disposed therein for receiving laser energy reflected from a predetermined area on said substrate and circuit features thereon and wherein said plurality of CCD elements are individually and simultaneously activated, said CCD being disposed proximate said substrate and circuit features thereon and operatively related thereto, said CCD being capable of; (i) substantially instantaneously receiving laser energy reflected from said substrate and cirucit features thereon; and (ii) generating a signal in response thereto, said signal varying with the intensity of said reflected laser energy; and (c) automatic analyzing means operatively connected to said CCD for correlating said signal received therefrom to a measurement representative of height of said cirucit features on said substrate and relative thereto, said analyzing means being adapted to analyze laser energy received by each of said plurality of CCD elements for a predetermined number of cycles so that non-linearities on said substrate and circuit features thereon are detected. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A non-contact system for detecting printed circuit wiring defects and for measuring circuit feature height relative to a substrate comprising:
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(a) a radiant energy source for illuminating said substrate and circuit features thereon; (b) scanning means disposed proximate said substrate and circuit features thereon and operatively related thereto, said scanning means being capable of; (i) substantially instantaneously receiving radiant energy reflected from said substrate and circuit features thereon; and (ii) generating a signal in response thereto, said signal varying with the intensity of said reflected energy; and (c) automatic analyzing means operatively connected to said scanning means for correlating said signal received therefrom to a measurement representative of height of said circuit features on said substrate and relative thereto, wherein said analyzing means is adapted to detect three categories of reflected radiant energy intensity, said categories being bounded and defined by two threshold levels and wherein one of said threshold levels separates the intensity of background radiant energy from the intensity of radiant energy reflected from said substrate. - View Dependent Claims (11)
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12. A method for detecting printed circuit wiring defects and measuring the height of the upper surface of a circuit feature relative to a substrate having a base and an upper surface, the steps comprising:
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(a) projecting radiant energy onto said substrate and circuit feature thereon; (b) providing a scanning means for receiving reflected radiant energy; (c) moving the radiant energy relative to said substrate such that said radiant energy is in focus at an initial focal plane below the base of said substrate and substantially parallel thereto, relative to said scanning means; (d) generating a signal in response to said reflected radiant energy, said signal being adapted to vary with the intensity thereof; (e) correlating said signal to a reference level of intensity representative of reflectivity; (f) moving said radiant energy relative to said substrate such that said radiant energy is in focus at a plane above said initial focal plane and substantially parallel thereto; (g) repeating steps (d) through (f) until the focused plane is above the level of the upper surface of said circuit feature; and (h) correlating said signals generated in step (e) to measurements representative of the height of said circuit features and printed circuit wiring defects. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification