Joule heating induced thermomigration failure in un-powered microbumps due to thermal crosstalk in 2.5D IC technology

Journal Article · Sun Aug 21 00:00:00 EDT 2016 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.4961219· OSTI ID:22598867

Li, Menglu; Kim, Dong Wook; Gu, Sam ^[1]; Parkinson, Dilworth Y.; Barnard, Harold ^[2]

---

1. Qualcomm, San Diego, California 92121 (United States)
2. Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States)

Thermal-crosstalk induced thermomigration failure in un-powered microbumps has been found in 2.5D integrated circuit (IC) circuit. In 2.5D IC, a Si interposer was used between a polymer substrate and a device chip which has transistors. The interposer has no transistors. If transistors are added to the interposer chip, it becomes 3D IC. In our test structure, there are two Si chips placed horizontally on a Si interposer. The vertical connections between the interposer and the Si chips are through microbumps. We powered one daisy chain of the microbumps under one Si chip; however, the un-powered microbumps in the neighboring chip are failed with big holes in the solder layer. We find that Joule heating from the powered microbumps is transferred horizontally to the bottom of the neighboring un-powered microbumps, and creates a large temperature gradient, in the order of 1000 °C/cm, through the un-powered microbumps in the neighboring chip, so the latter failed by thermomigration. In addition, we used synchrotron radiation tomography to compare three sets of microbumps in the test structure: microbumps under electromigration, microbumps under thermomigration, and microbumps under a constant temperature thermal annealing. The results show that the microbumps under thermomigration have the largest damage. Furthermore, simulation of temperature distribution in the test structure supports the finding of thermomigration.

• OSTI ID: 22598867
• Journal Information: Journal of Applied Physics, Vol. 120, Issue 7; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
ANNEALING
COMPARATIVE EVALUATIONS
COMPUTERIZED SIMULATION
DAMAGE
ELECTROPHORESIS
FAILURES
INTEGRATED CIRCUITS
JOULE HEATING
LAYERS
POLYMERS
SILICON
SUBSTRATES
SYNCHROTRON RADIATION
SYNCHROTRONS
TEMPERATURE DISTRIBUTION
TEMPERATURE GRADIENTS
TOMOGRAPHY
TRANSISTORS