Oxide adhesion characteristic of lead frame copper alloys

Author(s):  
Y. Tomioka ◽  
J. Miyake
2012 ◽  
Vol 560-561 ◽  
pp. 1048-1051 ◽  
Author(s):  
Juan Hua Su ◽  
Feng Zhang Ren ◽  
Ze Yang

The bending performance of lead frame materials is a very important in improving the quality of lead frame alloys and meeting the needs of high performance integrated circuit. The sringback amount of curvature variation of CuFeP , CuCrZrMg , CuNiSi and CuCrSnZn alloy are researched by numerical simulation. Bending model is built by 3D modeling software, and the necessary post-processing is carried out. The bending springback amount △K of the four kinds of copper alloy materials are calculated out. The results show that the sringback amount of curvature variation of four copper alloys at the same condition from large to small in turn is CuCrZrMg, CuNiSi, CuFeP, CuCrSnZn. Smaller the minimum relatively bending radius of copper alloy used in lead frame, less the springback amount and better the forming performance.


2011 ◽  
Vol 189-193 ◽  
pp. 3383-3390 ◽  
Author(s):  
Fu Xiang Huang ◽  
Ping Yin ◽  
Chun Tian Li ◽  
Ji Chao Li

The effect of chemical species of copper alloys on growth of intermetallic compounds (IMCs) at interface of solder/copper alloys for lead frame was investigated. The results have revealed that Cu is the main diffusing species during aging. After aged at 160°C for 300h, only a Cu6Sn5IMC layer is observed at SnPb/copper alloys interfaces. The growth rate of IMC on the Cu-Cr-Zr system alloys and Cu-Ni-Si alloys was much slower than that of IMC on the C19400 alloy. The Pb phase and voids were found to be inside the Cu6Sn5phase. Chromium, one of the alloying element in Cu-Cr-Zr-Zn alloys, has found to be segregated at the interface between the copper alloy/Cu6Sn5. Zn and Zr in the Cu-Cr-Zr-Zn system alloy are enriched in small amout inside the IMC. These observed results were discussed and analysed on the baisis of diffusion and growth kinetics.


Author(s):  
R. W. Fonda ◽  
D. E. Luzzi

The properties of polycrystalline materials are strongly dependant upon the strength of internal boundaries. Segregation of solute to the grain boundaries can adversely affect this strength. In copper alloys, segregation of either bismuth or antimony to the grain boundary will embrittle the alloy by facilitating intergranular fracture. Very small quantities of bismuth in copper have long been known to cause severe grain boundary embrittlement of the alloy. The effect of antimony is much less pronounced and is observed primarily at lower temperatures. Even though moderate amounts of antimony are fully soluble in copper, concentrations down to 0.14% can cause grain boundary embrittlement.


Author(s):  
W. A. Chiou ◽  
N. Kohyama ◽  
B. Little ◽  
P. Wagner ◽  
M. Meshii

The corrosion of copper and copper alloys in a marine environment is of great concern because of their widespread use in heat exchangers and steam condensers in which natural seawater is the coolant. It has become increasingly evident that microorganisms play an important role in the corrosion of a number of metals and alloys under a variety of environments. For the past 15 years the use of SEM has proven to be useful in studying biofilms and spatial relationships between bacteria and localized corrosion of metals. Little information, however, has been obtained using TEM capitalizing on its higher spacial resolution and the transmission observation of interfaces. The research presented herein is the first step of this new approach in studying the corrosion with biological influence in pure copper.Commercially produced copper (Cu, 99%) foils of approximately 120 μm thick exposed to a copper-tolerant marine bacterium, Oceanospirillum, and an abiotic culture medium were subsampled (1 cm × 1 cm) for this study along with unexposed control samples.


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