Electromigration test structures for void localization

A method for localizing electromigration-induced voids in an electromigration (EM) test structure, the method comprising.

• connecting one or more first force probes to a first force pad of an EM test element;
• connecting a first sense probe to a first sense pad of the EM test element, wherein the EM test element forms a conductive pathway between the first force pad and the first sense pad;
• connecting one or more second force probes to a second force pad of a stress line, wherein:
• a via is in contact with a surface of the EM test element and a surface of a first end portion of the stress line such that the via electrically connects the EM test element to the stress line;
• and
• a second end portion of the stress line includes the second force pad such that the second force pad defines, at least in part, a conductive pathway between the first force pad and the second force pad;
• connecting a second sense probe to a second sense pad of the stress line that is included in the second end portion of the stress line, the second sense pad defining, at least in part, a conductive pathway between the first sense pad and the second sense pad;
• and
• connecting a third force probe to a third sense pad of the stress line that is included in the first end portion of the stress line, the third sense pad defining, at least in part, a conductive pathway between the first sense pad and the third sense pad.

A computer system for localizing electromigration-induced voids in an electromigration (EM) test structure, the computer system comprising:

• one or more computer processors;
• one or more computer readable storage media;
• program instructions stored on the one or more computer readable storage media for execution by at least one of the one or more processors, the program instructions comprising:
• program instructions to send an electrical current between one or more first force probes and one or more second force probes, wherein:
• the one or more first force probes are connected to a first force pad of an EM test element;
• the one or more second force probes are connected to a second force pad of a stress line;
• a via is in contact with a surface of the EM test element and a surface of a first end portion of the stress line such that the via electrically connects the EM test element to the stress line;
• and
• a second end portion of the stress line includes the second force pad such that the second force pad defines, at least in part, a conductive pathway between the first force pad and the second force pad;
• program instructions to measure electrical resistance between a first sense probe and a second sense probe using a four-terminal sensing technique, wherein:
• the first sense probe is connected to a first sense pad of the EM test element, the EM test element forming a conductive pathway between the first force pad and the first sense pad;
• and
• the second sense probe is connected to a second sense pad that is included in the second end portion of the stress line, the second sense pad defining, at least in part, a conductive pathway between the first sense pad and the second sense pad;
• and
• program instructions to measure electrical resistance between the first sense probe and a third sense probe using a four-terminal sensing technique in response to determining that electrical resistance between the first sense probe and the second sense probe has increased, wherein the third sense probe is connected to a third sense pad of the stress line that is included in the first end portion of the stress line, the third sense pad defining, at least in part, a conductive pathway between the first sense pad and the third sense pad.