Browsing by Author "Hsiao, H. Y."

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Effect of Al-Trace Width on the Electromigration Failure Time of Flip-Chip Solder Joints
(2010-10-01)
Liang, S. W.
;
Hsiao, H. Y.
;
Chen, Chih
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The effect of Al-trace width on electromigration (EM) in flip-chip solder joints was investigated experimentally. EM tests were performed on eutectic Sn-Ag solders with 40-mu m- and 100-mu m-wide Al traces. Under the same stressing conditions (0.5 A at 165 degrees C), the failure time was 44.1 h for solder joints with 40-mu m-wide traces and 250.1 h for solder joints with 100-mu m-wide traces. The Al-trace width influenced both the current crowding and the Joule heating effects. Thus, both effects are responsible for the significant difference in failure time. Finite-element analysis was used to examine the current crowding effect in solder bumps with Al traces of the two different widths. The results showed that the current crowding effect was slightly higher in joints with 40-mu m-wide traces. In addition, the temperature coefficient was used to measure the real temperatures in the solder bumps during EM. The results indicated that the width of the Al traces had a substantial influence on the Joule heating effect. The measured temperature in the solder bump was 218.2 degrees C and 172.2 degrees C for the bump with 40-mu m- and 100-mu m-wide Al traces, respectively. This difference in the Joule heating effect plays a crucial role in causing the difference in the failure time of solder joints with the two different widths.
Effect of Al-Trace Width on the Electromigration Failure Time of Flip-Chip Solder Joints
(2010-10-01)
Liang, S. W.
;
Hsiao, H. Y.
;
Chen, Chih
;
材料科學與工程學系
;
Department of Materials Science and Engineering
The effect of Al-trace width on electromigration (EM) in flip-chip solder joints was investigated experimentally. EM tests were performed on eutectic Sn-Ag solders with 40-mu m- and 100-mu m-wide Al traces. Under the same stressing conditions (0.5 A at 165 degrees C), the failure time was 44.1 h for solder joints with 40-mu m-wide traces and 250.1 h for solder joints with 100-mu m-wide traces. The Al-trace width influenced both the current crowding and the Joule heating effects. Thus, both effects are responsible for the significant difference in failure time. Finite-element analysis was used to examine the current crowding effect in solder bumps with Al traces of the two different widths. The results showed that the current crowding effect was slightly higher in joints with 40-mu m-wide traces. In addition, the temperature coefficient was used to measure the real temperatures in the solder bumps during EM. The results indicated that the width of the Al traces had a substantial influence on the Joule heating effect. The measured temperature in the solder bump was 218.2 degrees C and 172.2 degrees C for the bump with 40-mu m- and 100-mu m-wide Al traces, respectively. This difference in the Joule heating effect plays a crucial role in causing the difference in the failure time of solder joints with the two different widths.
Temperature dependent responsivity of quantum dot infrared photodetectors
(2007-04-01)
Wang, S. Y.
;
Lo, M. C.
;
Hsiao, H. Y.
;
Ling, H. S.
;
Lee, C. P.
Temperature dependent behavior of the responsivity of InAs/GaAs quantum dot infrared photoderectors was investigated with detailed measurement of the current gain. The current gain varied about two orders of magnitude with 100 K temperature change. Meanwhile, the change in quantum efficiency is within a factor of 10. The dramatic change of the current gain is explained by the repulsive coulomb potential of the extra carriers in the QDs. With the measured current gain, the extra carrier number in QDs was calculated. More than one electron per QD could be captured as the dark current increases at 150 K. The extra electrons in the QDs elevated the Fermi level and changed the quantum efficiency of the QDIPs. The temperature dependence of the responsivity was qualitatively explained with the extra electrons. (c) 2006 Elsevier B.V. All rights reserved.
The effect of a concentration gradient on interfacial reactions in microburaps of Ni/SnAg/Cu during liquid-state soldering
(2012-05-01)
Huang, Y. S.
;
Hsiao, H. Y.
;
Chen, Chih
;
Tu, K. N.
;
材料科學與工程學系
We report new findings in Ni/SnAg solder/Cu microbumps having a reduced solder thickness in the range of 40-10 mu m; the growth rate of the intermetallic compounds depends strongly on the solder thickness. In the Ni/40 mu m solder/Cu samples., the compound which grew on the Ni side grew slightly faster than that on the Cu side. However, the growth reverses as the solder thickness decreases below 20 pm due to the change in Cu and Ni concentration gradients in the solder. (C) 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.