skip to main content

Title: Characterization of micro-contact resistance between a gold nanocrystalline line and a tungsten electrode probe in interconnect fatigue testing

An electromechanically-coupled micro-contact resistance measurement system is built to mimic the contact process during fatigue testing of nanoscale-thickness interconnects using multiple probe methods. The design combines an optical microscope, high-resolution electronic balance, and micromanipulator-controlled electric probe, and is coupled with electrical measurements to investigate microscale contact physics. Experimental measurements are performed to characterize the contact resistance response of the gold nanocrystalline pad of a 35-nm-thick interconnect under mechanical force applied by a tungsten electrode probe. Location of a stable region for the contact resistance and the critical contact force provides better understanding of micro-contact behavior relative to the effects of the contact force and the nature of the contact surface. Increasing contact temperature leads to reduced contact resistance, softens the pad material, and modifies the contact surface. The stability of both contact resistance and interconnect resistance is studied under increasing contact force. Major fluctuations emerge when the contact force is less than the critical contact force, which shows that temporal contact resistance will affect interconnect resistance measurement accuracy, even when using the four-wire method. This performance is demonstrated experimentally by heating the Au line locally with a laser beam. Finally, the contact resistances are calculated using the LET (Li–Etsion–Talke) modelmore » together with combined Holm and Sharvin theory under various contact forces. Good agreement between the results is obtained. This research provides a way to measure change in interconnect line resistance directly under a stable contact resistance regime with a two-wire method that will greatly reduce the experimental costs.« less
Authors:
;  [1] ;  [1] ;  [2]
  1. Department of Engineering Mechanics, AML, Tsinghua University, Beijing 100084 (China)
  2. (China)
Publication Date:
OSTI Identifier:
22305906
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 10; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 77 NANOSCIENCE AND NANOTECHNOLOGY; ACCURACY; CRYSTALS; ELECTRIC CONDUCTIVITY; ELECTRIC CONTACTS; ELECTRIC PROBES; ELECTRODES; GOLD; HEATING; LASER RADIATION; NANOSTRUCTURES; OPTICAL MICROSCOPES; PHOTON BEAMS; RESOLUTION; SURFACES; THICKNESS