1,720,972 research outputs found
Correlation between chemical reaction and brittle fracture found in electroless Ni(P)/immersion gold-solder interconnection
No full textOccurrence of brittle interfacial fracture at an electroless Ni(P)/immersion gold-solder joint has long been a serious problem not yet fully understood. In our previous report on the electroless Ni(P) [J. Mater. Res. 19, 2428 (2004)], it was shown that crystallization of the Ni(P) film and growth of the Ni3SnP layer were accelerated after the intermetallic compound (IMC) spalling, and accurate failure locus of the brittle fracture due to so-called "IMC spalling induced microstructure degradation of the Ni(P) film" is presented for the first time in this communication. For Sn-3.0Ag-0.5Cu solder joints, (Ni,Cu)(3)Sn-4 and/or (Cu,Ni)(6)Sn-5 ternary IMCs formed at the interface, and neither spalling nor interfacial fracture was observed. For Sn-3.5Ag joints, Ni3Sn4 compound formed, and the brittle fracture occurred through the Ni3SnP layer in the solder pads where Ni3Sn4 had spalled. Since the Ni3SnP layer is getting thicker during or after Ni3Sn4 spalling, control of IMC spalling is crucial to ensure the reliability of Ni(P)/solder system
화학증착법으로 제조한 다이아몬드막의 고유응력에 대한 탄성/크리프 해석(An Elastic/Plastic Analysis of The Intrinsic Stresses in CVD Diamond Films)
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Study of the reaction mechanism between electroless Ni-P and Sn and its effect on the crystallization of Ni-P
No full textThe reaction mechanism between electroless Ni-P and Sn was investigated to understand the effects of Sn on solder reaction-assisted crystallization at low temperatures as well as self-crystallization of Ni-P at high temperatures. Ni3Sn4 starts to form in a solid-state reaction well before Sn melts. Heat of reaction for Ni3Sn4 was measured during the Ni-P and Sn reaction (241.2 J/g). It was found that the solder reaction not only promotes crystallization at low temperatures by forming Ni3P in the P-rich layer but also facilitates self-crystallization of Ni-P by reducing the transformation temperature and heat of crystallization. The presence of Sn reduces the self-crystallization temperature of Ni-P by about 10degreesC. The heat of crystallization also decreases with an increased Sn thickness
Delaying coherence requests to enhance the performance of strict consistency models
No full textAdvances in ILP techniques enable strict consistency models to relax memory order through speculative execution of memory operations. However, ordering constraints still hinder the performance because speculatively executed operations cannot be committed out of program order for the possibility of mis-speculation. In this paper, we propose a new technique which allows memory operations to be non-speculatively committed out of order without violating consistency constraints. Consistency constraints are guaranteed through delaying the coherence requests. The proposed technique also improves the performance of spin lock primitives such as TTS lock or MCS lock. Through delaying early acquire requests, the lock transfer time can be improved when there is high contention for a lock
Spalling of intermetallic compounds during the reaction between lead-free solders and electroless Ni-P metallization
No full textIntermetallic compound (IMC) spalling front electroless Ni-P film was investigated with lead-free solders in terms of solder-deposition methods (electroplating, solder paste, and thin foil), P content in the Ni-P film (4.6, 9, and 13 wt% P), and solder thickness (120 versus .200 mum). The reaction of Ni-P with Sn3.5Ag paste easily led to IMC spalling after 2-min reflow at 250 degreesC while IMCs adhered to the Ni-P layer after 10-min reflow with electroplated Sn or Sn3.5Ag. It has been shown that not only the solder composition but also the deposition method is important for IMC spalling from the NI-P layer. The spalling increased with P content as well as with solder volume. Ni3Sn4 intermetallics formed as a needle-shaped morphology at an early stage and changed into a chunk-shape. Needle-shaped compounds exhibited a higher propensity for spalling than chunk-shaped compounds because many channels among the needle-shaped IMCs facilitated Sn penetration. A reaction between the penetrated Sn and the Ni3P layer formed a Ni3SnP layer and Ni3Sn4 IMCs spalled off the Ni3SnP surface. Dewetting of solder from the Ni3SnP layer, however, did not occur even after spalling of most IMCs
Effects of phosphorus content on the reaction of electroless Ni-P with Sn and crystallization of Ni-P
No full textThe reaction between electroless Ni-P and Sn and the crystallization behavior of Ni-P were investigated to better understand the effect of P content on the Ni-P layer. Electroless Ni-P specimens with three different P contents, 4.6 wt.%, 9 wt.%, and 13 wt.%, were used to study the effect of the P content and the microstructure of Ni-P on the subsequent crystallization and intermetallic compound (IMC) formation during the reaction between Ni-P and electroplated Sn. Ni3Sn4 was the major phase formed in all samples heated up to 300degreesC, which totally transformed into Ni3Sn2 when samples were heated up to 450degreesC and the Sn layer was 0.5-mum thick. The IMC formed on the nanocrystalline Ni-P showed stronger texture compared to that formed on the amorphous Ni-P Both the IMC thickness and density decreased with P content in the Ni-P layer, and Ni3Sn4 morphologies varied with P content. Dissolution of Ni into Sn increased with P content, which made IMC size in the bulk Sn increase with P content
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