Localization of defects of a metallic layer of a semiconductor circuit
First Claim
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1. A method for detecting defects in an opaque layer of a semiconductor wafer, comprising:
- projecting a directed light source beam onto a surface of the semiconductor wafer;
reverse biasing a PN junction located in the semiconductor wafer proximate to the opaque layer wherein at least one transparent layer is interposed between the opaque layer and the PN junction; and
detecting a current flow in the PN junction.
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Abstract
A method for locating possible defects on an opaque layer deposited on a production wafer of a semiconductor circuit, consisting in locally radiating an upper surface of the wafer by means of a laser, and detecting the occurrence of a current in a diode constituted by a PN junction placed under the opaque layer to be examined.
24 Citations
19 Claims
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1. A method for detecting defects in an opaque layer of a semiconductor wafer, comprising:
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projecting a directed light source beam onto a surface of the semiconductor wafer; reverse biasing a PN junction located in the semiconductor wafer proximate to the opaque layer wherein at least one transparent layer is interposed between the opaque layer and the PN junction; and detecting a current flow in the PN junction. - View Dependent Claims (2, 3, 4)
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5. A method for detecting defects in an opaque layer of a semiconductor wafer, comprising:
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projecting a directed light source beam onto a surface of the semiconductor wafer; reverse biasing a PN junction proximate to the opaque layer wherein at least one transparent layer is interposed between the directed light source beam and the opaque layer, the opaque layer being located between the directed light source beam and the PN junction; and detecting a current flow in the PN junction. - View Dependent Claims (6, 7, 8, 9, 10)
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11. A method for detecting defects in an opaque layer of a semiconductor wafer, comprising:
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projecting a directed light source beam toward the semiconductor wafer; reverse biasing a PN junction proximate to the opaque layer; passing the directed light source beam through a transparent layer interposed between the opaque layer and the PN junction; and detecting a current flow in the PN junction. - View Dependent Claims (12, 13, 14)
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15. A method for detecting defects in an opaque portion of a semiconductor wafer, comprising:
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reverse biasing a PN junction proximate to the opaque portion; directing a light source beam toward the opaque portion; positioning at least one of the light source beam and the opaque portion relative to the other of the light source beam and the opaque portion to block at least a portion of the light beam from passing to the PN junction; moving at least one of the light source beam and the opaque portion relative to the other of the light source beam and the opaque portion to allow the light source beam to pass through a defect area of the opaque portion to the PN junction; and monitoring the PN junction to detect a current flow at the PN junction. - View Dependent Claims (16, 17, 18, 19)
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Specification