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71.
Investigation of growth behavior of Al-Cu intermetallic compounds in Cu wire bonding 总被引:1,自引:0,他引:1
In this work, we investigate the intermetallic compound formation in Cu wire bonded device. Voids near the Cu side at the bond interface are clearly seen. Nevertheless, these voids do not seem to interfere with the function of the unit. High temperature storage test (HTST) results show that there are Al2Cu and AlCu in the damaged unit while Al2Cu and Al4Cu9 appear in the good unit. The results clearly show that the Al layer is exhausted in the damaged unit while those with Al4Cu9 on the Cu side pass HTST with unconsumed Al. Theoretical calculations indicate that AlCu and Al4Cu9 are energetically more favorable than Al2Cu, which is consistent with the reported IMC forming sequence. Formation energy of AlCu is compatible but slightly lower to that of Al4Cu9, suggesting AlCu tends to be the most stable phase among all. The reason why the Al layer is completely consumed in one case and some Al layer remains in the other is due to the fact that the formation of AlCu requires more than twice the amount of Al than Al4Cu9 for the same amount of Cu consumed. The complete consumption of Al is proposed as the reason responsible for the failure of the damaged unit. 相似文献
72.
W. T. Lee S. X. Ding D. K. Sun C. I. Hsiao C. P. Chang L. Chang P. W. Kao 《Metallurgical and Materials Transactions A》2011,42(9):2909-2916
Ultrafine-grained (UFG) Mg-3Al-1Zn (AZ31) alloys with gain sizes ranging from 0.46 to 3.22 μm were prepared by equal channel angular pressing (ECAP) and annealing. The deformation structure of UFG AZ31 alloy resulting from uniaxial compression was studied by optical and electron microscopy. The deformation was noted to proceed with the development of shear bands (SBs), which has not been reported in an UFG hcp metal. Characterization of these SBs was performed, and comparison with the SBs formed in UFG bcc and fcc metals was given. { 10[`1]2} { 10bar{1}2} tension twins inside SBs were found in all specimens compressed, irrespective of the grain size. Discussion on the limiting grain size of twinning in the UFG AZ31 alloy is also given. 相似文献
73.
Planar Heterojunction Perovskite Solar Cells Incorporating Metal–Organic Framework Nanocrystals 下载免费PDF全文
74.
HM, an HMG1-like mitochondrial DNA-binding protein, is required for maintenance of the yeast mitochondrial genome when cells are grown in glucose. To better understand the role of HM in mitochondria, we have isolated several multicopy suppressors of the temperature-sensitive defect associated with an abf2 null mutation (lacking HM protein). One of these suppressors, SHM1, has been characterized at the molecular level and is described herein. SHM1 encodes a protein (SHM1p) that shares sequence similarity to a family of mitochondrial carrier proteins. On glycerol medium, where mitochondrial function is required for growth, shm1 deletion mutants are able to grow, whereas shm1 abf2 double mutants are severely inhibited. These results suggest that SHM1p plays an accessory role to HM in the mitochondrion. The GenBank Accession Number for the SHM1 sequence is U08352. 相似文献
75.
76.
Liao Shih-Wei Kuang Shao-Yun Kao Chia-Lung Tu Chia-Heng 《Journal of Signal Processing Systems》2019,91(3-4):219-233
Journal of Signal Processing Systems - New programming models have been developed to embrace contemporary heterogeneous machines, each of which may contain several types of processors, e.g., CPUs,... 相似文献
77.
LE Shields SB Uhrich CA Komarniski MH Wener TC Winter 《Canadian Metallurgical Quarterly》1996,15(11):735-739
The purpose of this retrospective study was to evaluate the utility of routine measurement of amniotic fluid alpha-fetoprotein levels at the time of second trimester genetic amniocentesis (mean gestational age, 17.3 weeks +/- 2.5 weeks standard deviation; median, 16.8 weeks; range, 15 to 22 weeks). During the study period 7174 patients underwent second trimester genetic amniocentesis. Outcome data were available in all cases. In 79 (1.1%) cases the amniotic fluid alpha-fetoprotein level was > or = 2.0 multiples of the median. Thirty-three of the 79 (42%) patients had normal ultrasonograms, and in 31 of 33 (94%) the amniotic fluid alpha-fetoprotein level was between 2.0 and 3.0 multiples of the median. Forty-six of the 79 (58%) patients had abnormal ultrasonographic findings, and of these, 82% were neural tube defects, abdominal wall defects, or cystic hygromas. Acetylcholinesterase was positive in 37 cases, all of which had abnormal ultrasonographic findings. None of the fetuses with negative findings on sonographic screening had detectable abnormalities at birth. In this study, with over 7000 patients, amniotic fluid alpha-fetoprotein and acetylcholinesterase levels did not increase the detection of fetal abnormalities. On the basis of these results, routine measurement of amniotic fluid alpha-fetoprotein level at the time of routine genetic amniocentesis (15 to 22 weeks) does not appear justified. 相似文献
78.
79.
Staphylococcus aureus is a pathogen important in causing human infections and intoxication. A sensitive fiber-optic that produces evanescent waves was developed for the detection of protein A, a product secreted only by S. aureus. In the immunosensor, a 40-mV argon-ion laser that generated laser light at 488 nm was used together with plastic optical fiber and antibodies to protein A were physically adsorbed onto the fiber. The principle of the detection involved a sandwich immunoassay with fluorescein isothiocyanate conjugated with anti-(protein A) immunoglobulin G to produce signals of the antigen-antibody reaction. The detection limit was 1 ng of protein A per milliliter. The fiber-optic immunosensor could be used for rapid and specific detection of S. aureus in clinical specimens and foods. 相似文献
80.