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Using Capacitance Measurements to Localize the Position of Opens in Serpentine Metal Lines

IP.com Disclosure Number: IPCOM000034675D
Original Publication Date: 1989-Apr-01
Included in the Prior Art Database: 2005-Jan-27
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Kasper, M: AUTHOR [+3]

Abstract

A widely applied method of checking the process performance of semiconductor chip production uses serpentine metal lines. For yield analysis, resistance measurements of opens and shorts between the serpentine parts are sufficient. However, for analyzing the cause of a fault, its position has to be known. For this purpose, the capacitance of the serpentine is measured with respect to an insulated conductive sublayer. The values thus obtained are a direct measure of the position of the open. As the capacitance may be measured from either side of the serpentine, one or two opens are accurately localized. More than two opens (which are rather unlikely to occur in products) are detected as two opens.

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Using Capacitance Measurements to Localize the Position of Opens in Serpentine Metal Lines

A widely applied method of checking the process performance of semiconductor chip production uses serpentine metal lines. For yield analysis, resistance measurements of opens and shorts between the serpentine parts are sufficient. However, for analyzing the cause of a fault, its position has to be known. For this purpose, the capacitance of the serpentine is measured with respect to an insulated conductive sublayer. The values thus obtained are a direct measure of the position of the open. As the capacitance may be measured from either side of the serpentine, one or two opens are accurately localized. More than two opens (which are rather unlikely to occur in products) are detected as two opens. Upon completion of capacitance measurement, the distance to the open is calculated in numbers of serpentine lines and the cause of failure inspected by microscope. The described method of localizing opens by capacitance measurements can be applied if the measured capacitance is a well-defined function of the distance between the contacted tab and the open. A serpentine metal line in a test structure, which is separated from another electrode (substrate or another serpentine) by an insulating material, can be modelled as a ladder of RC elements. For convenience, each ladder element is represented by one straight line of the serpentine. If the number of ladder elements is repeatedly i...