Electromigration failure mechanisms for SnAg3.5 solder bumps on Ti/Cr-Cu/Cu and Ni(P)/Au metallization pads

Journal Article · Fri Oct 15 00:00:00 EDT 2004 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.1788837· OSTI ID:20662119

Shao, T L; Chen, Y H; Chiu, S H; Chih, Chen ^[1]

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1. Department of Material Science and Engineering, National Chiao Tung University, Hsin-chu 300, Taiwan (China)

The electromigration behavior of SnAg3.5 solder bumps is investigated under the current densities of 1x10{sup 4} A/cm{sup 2} and 5x10{sup 3} A/cm{sup 2} at 150 deg. C. Different failure modes were observed for the two stressing conditions. When stressed at 1x10{sup 4} A/cm{sup 2}, damage occurred in both the anode/chip side and the cathode/chip side. However, failure happened only in the cathode/chip side under the stressing of 5x10{sup 3}A/cm{sup 2}. A three-dimensional simulation of the current-density distribution was performed to provide a better understanding of the current-crowding behavior in the solder bump. The current-crowding effect was found to account for the failure in the cathode/chip side. In addition, both the temperature increase and the thermal gradients were measured during the two stressing conditions. The measured temperature increase due to Joule heating was as high as 54.5 deg. C, and the thermal gradient reached 365 deg. C/cm when stressed by 1x10{sup 4}A/cm{sup 2}. This induced thermal gradient may cause atoms to migrate from the chip side to the substrate side, contributing to the failure in the anode/chip side. Moreover, the formation of intermetallic compounds in the anode/chip side may also be responsible for the failure in the anode/chip side.

• OSTI ID: 20662119
• Journal Information: Journal of Applied Physics, Vol. 96, Issue 8; Other Information: DOI: 10.1063/1.1788837; (c) 2004 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
ANODES
CATHODES
CHROMIUM
COPPER
CURRENT DENSITY
ELECTROPHORESIS
FAILURES
GOLD
INTEGRATED CIRCUITS
INTERMETALLIC COMPOUNDS
JOULE HEATING
MORPHOLOGY
NICKEL
SILVER ALLOYS
SIMULATION
SUBSTRATES
TEMPERATURE GRADIENTS
THREE-DIMENSIONAL CALCULATIONS
TIN ALLOYS
TITANIUM