Contactless technique for evaluating a fabrication of a wafer
First Claim
1. A method for evaluating fabrication of at least a portion of a wafer, the method comprising:
- (a) independently detecting and activating a plurality of test structures distributed at a plurality of locations on the portion of the wafer;
the plurality of test structures being formed during a first fabrication process to establish electrical connectivity for a first set of elements which include the plurality of test structures, each test structure being activated and then detected without electrical or physical connectivity to any circuit elements that are part of a design of the product wafer;
wherein independent detecting and activating is performed immediately after the first fabrication process;
(b) programmatically correlating, with use of one or more computers, an output of one or more of the plurality of test structures to a specified performance parameter that is indicative of an attribute that results from performance of at least one or more fabrication processes for the wafer.
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Abstract
The fabrication of the wafer may be analyzed starting from when the wafer is in a partially fabricated state. The value of a specified performance parameter may be determined at a plurality of locations on an active area of a die of the wafer. The specified performance parameter is known to be indicative of a particular fabrication process in the fabrication. Evaluation information may then be obtained based on a variance of the value of the performance parameter at the plurality of locations. This may be done without affecting a usability of a chip that is created from the die. The evaluation information may be used to evaluate how one or more processes that include the particular fabrication process that was indicated by the performance parameter value was performed.
180 Citations
22 Claims
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1. A method for evaluating fabrication of at least a portion of a wafer, the method comprising:
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(a) independently detecting and activating a plurality of test structures distributed at a plurality of locations on the portion of the wafer;
the plurality of test structures being formed during a first fabrication process to establish electrical connectivity for a first set of elements which include the plurality of test structures, each test structure being activated and then detected without electrical or physical connectivity to any circuit elements that are part of a design of the product wafer;wherein independent detecting and activating is performed immediately after the first fabrication process; (b) programmatically correlating, with use of one or more computers, an output of one or more of the plurality of test structures to a specified performance parameter that is indicative of an attribute that results from performance of at least one or more fabrication processes for the wafer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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Specification