Browse Prior Art Database

Metal Electromigration Sensor

IP.com Disclosure Number: IPCOM000047055D
Original Publication Date: 1983-Sep-01
Included in the Prior Art Database: 2005-Feb-07
Document File: 2 page(s) / 28K

Publishing Venue

IBM

Related People

Hsieh, CM: AUTHOR [+2]

Abstract

A method is provided for detecting and measuring the electromigration of metal lines. This method is sensitive, accurate, rapid and convenient, and operates such that application of an accelerated high current density and high temperature may not be required. Conventional methods to test the electromigration of metal stripe in integrated circuits is typically effected by applying high current density and high temperature to the metal line and measuring the line resistance. If the electromigration is severe, the metal line becomes highly resistive or an open circuit. However, if the metal migration is moderate, the metal mass will migrate at a very slow rate. The metal line resistance may not have noticeable change, and it may be difficult to evaluate the result.

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Metal Electromigration Sensor

A method is provided for detecting and measuring the electromigration of metal lines. This method is sensitive, accurate, rapid and convenient, and operates such that application of an accelerated high current density and high temperature may not be required. Conventional methods to test the electromigration of metal stripe in integrated circuits is typically effected by applying high current density and high temperature to the metal line and measuring the line resistance. If the electromigration is severe, the metal line becomes highly resistive or an open circuit. However, if the metal migration is moderate, the metal mass will migrate at a very slow rate. The metal line resistance may not have noticeable change, and it may be difficult to evaluate the result. It is known that mechanical stress on a device will cause variation in energy band structure and change minority carrier density on p-n junctions. The current-voltage characteristics of diodes or transistors vary as a function of the stress levels applied to the cathode or emitter. The proposed structure is shown in Figs. 1A and 1B. As shown in Fig. 1A, the metal line 1, which is under study for electromigration, lays over emitter contact 2 of sense transistor 3. Electrical current flows from pad 4 to pad 5 for stress testing. The metal line on the right-hand side of the emitter contact is designed to have a narrow section 6 such that it will be the highest current density an...