Contactless technique for evaluating a fabrication of a wafer
First Claim
1. A method for evaluating manufacturing of a product wafer, the method comprising the steps of:
- measuring an electrical activity from multiple activated circuits located at a plurality of locations on an active area of a die of the wafer, wherein the wafer is in a partially completed state;
wherein measuring the electrical activity includes directly measuring the electrical activity using the off-wafer probe so as to associate the electrical activity as measured from each of the activated circuits with a corresponding one of the plurality of locations where that activated circuit is located;
determining performance-related information of the die or wafer by relating one or more physical or electrical characteristics of at least the portion of the wafer to data corresponding to the measured electrical activity;
wherein the step of measuring the electrical activity is performed without physically contacting the active area of the die of the wafer, and without affecting subsequent manufacturing of the wafer into final product form after measuring the electrical activity; and
wherein determining performance-related information includes (i) determining values of a performance parameter from the measured electrical activity of activated circuits at the plurality of the locations, and (ii) determining variance from the determined values of the performance parameter.
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Accused Products
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.
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Citations
57 Claims
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1. A method for evaluating manufacturing of a product wafer, the method comprising the steps of:
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measuring an electrical activity from multiple activated circuits located at a plurality of locations on an active area of a die of the wafer, wherein the wafer is in a partially completed state; wherein measuring the electrical activity includes directly measuring the electrical activity using the off-wafer probe so as to associate the electrical activity as measured from each of the activated circuits with a corresponding one of the plurality of locations where that activated circuit is located; determining performance-related information of the die or wafer by relating one or more physical or electrical characteristics of at least the portion of the wafer to data corresponding to the measured electrical activity; wherein the step of measuring the electrical activity is performed without physically contacting the active area of the die of the wafer, and without affecting subsequent manufacturing of the wafer into final product form after measuring the electrical activity; and wherein determining performance-related information includes (i) determining values of a performance parameter from the measured electrical activity of activated circuits at the plurality of the locations, and (ii) determining variance from the determined values of the performance parameter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An apparatus comprising a computer readable storage device, wherein the computer readable storage device stores instructions for evaluating manufacturing of a product wafer, wherein at least some of the instructions are executable to enable the apparatus to:
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determine, at a plurality of locations on an active area of a die in the product wafer, a value of a specified performance parameter, wherein the specified performance parameter is known to be indicative of a result of one or more fabrication steps in the fabrication; wherein the value of the specified performance parameter is determined by attributing an electrical activity directly measured from each of a plurality of activated circuits with a corresponding location of that activated circuit without physically contacting or altering the active areas of the die, so as to not affect usability of the product wafer when completed; determine a variance in the values of the specified performance parameter from the measured electrical activity at the plurality of locations; and obtain evaluation information based on the variance of the value of the performance parameter, wherein the evaluation information enables evaluation of how the one or more fabrication steps were performed.
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22. A method for evaluating the manufacturing of a product wafer, the method comprising:
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measuring, using an off-wafer probe, an electrical activity from multiple activated circuits located at a plurality of locations on an active area of a die of the product wafer, wherein the wafer is in a partially completed state; wherein measuring the electrical activity includes directly measuring the electrical activity using the off wafer probe so as to associate the electrical activity as measured from each of the activated circuits with a corresponding one of the plurality of locations where that activated circuit is located; wherein measuring the electrical activity is performed without contacting the wafer and without affecting completion of manufacturing the wafer into product form; obtaining a value of a performance parameter at the plurality of locations, the value of the performance parameter at each of the plurality of locations being based on the directly measured electrical activity of one or more activated circuits at the corresponding location of each of the one or more activated circuits; and evaluating one or more physical or electrical characteristics of at least the portion of the wafer in the partially completed state by analyzing the values of the performance parameter at the plurality of locations; wherein analyzing the values of the performance parameter includes determining variance in the values of performance parameter that are obtained from activated circuits located at different locations of the wafer that include the active area. - View Dependent Claims (23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57)
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Specification