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The effect of under-bump-metallization (UBM) on electromigration was investigated at temperatures ranging from 135 o C to 165 o C. The UBM structures were examined: 5-µm-Cu/3-µm-Ni and 5 µm Cu. Experimental results show that the solder joint with the Cu/Ni UBM has a longer electromigration lifetime than the solder joint with the Cu UBM. Three important(More)
Solder joints with Cu columns appear to be one of the best structures to resist electromigration. Three-dimensional thermoelectrical analysis was employed to simulate the current density and temperature distributions for eutectic SnPb solder bumps with 0.5, 5, 25, 50, and 100 lm Cu under bump metalli-zation (UBM). It was found that the hot spots and current(More)
Highly oriented [111] Cu grains with densely packed nanotwins have been fabricated by direct-current electroplating with a high stirring rate. The [111]-oriented and nanotwinned Cu (nt-Cu) allow for the unidirectional growth of Cu(6)Sn(5) intermetallics in the microbumps of three-dimensional integrated-circuit packaging; a uniform microstructure in a large(More)
Three dimensional thermo-electrical analysis was employed to simulate the current density and temperature distributions for eutectic SnAg solder bumps with shrinkage bump sizes. It was found that the current crowding effects in the solder were reduced significantly for smaller solder joints. Hot-spot temperatures and thermal gradient were increased upon(More)
  • Chih Chen
  • 2006
With the portable devices becoming smaller and more compact in size, flip-chip technology has been adopted for fine-pitch packaging in microelectronics industry. Area array of tiny solder joints can be fabricated on Si chips to achieve high-density packaging. In addition, as the required performance continues to increase, the input/output (I/O) pin count of(More)
As microelectronic industry develops 3D IC on the basis of through-Si-vias (TSV) technology, the processing and reliability of microbumps, which are used to interconnect the stacking chips, is being actively investigated. Due to the reduction in size of microbumps, the diameter is about one order of magnitude smaller than that of flip chip solder joints,(More)
Articles you may be interested in Influence of Cu column under-bump-metallizations on current crowding and Joule heating effects of electromigration in flip-chip solder joints Effect of void propagation on bump resistance due to electromigration in flip-chip solder joints using Kelvin structure Appl. Investigation of void nucleation and propagation during(More)
Direct Cu-to-Cu bonding was achieved at temperatures of 150-250 °C using a compressive stress of 100 psi (0.69 MPa) held for 10-60 min at 10(-3) torr. The key controlling parameter for direct bonding is rapid surface diffusion on (111) surface of Cu. Instead of using (111) oriented single crystal of Cu, oriented (111) texture of extremely high degree,(More)
We investigate the growth of Cu films on two different Cu seed layers: one with regular <111>-oriented grains and the other with very strong <111>-preferred orientation. It is found that densely-packed nanotwinned Cu (nt-Cu) can be grown by pulsed electroplating on the strong <111>-oriented Cu seed layer without a randomly-oriented transition layer between(More)
The heterojunction effects of TiO2 nanotubes on photoconductive characteristics were investigated. For ITO/TiO2/Si diodes, the photocurrent is controlled either by the TiO2/Si heterojunction (p-n junction) or the ITO-TiO2 heterojunction (Schottky contact). In the short circuit (approximately 0 V) condition, the TiO2-Si heterojunction dominates the(More)