Nurul Razliana Abdul Razak
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Preferred name
Nurul Razliana Abdul Razak
Official Name
Nurul Razliana, Abdul Razak
Alternative Name
Razak, N. R.Abdul
Razak, N. R.A.
Abdul Razak, N. R
Razak, Nurul Razliana Abdul
Main Affiliation
Scopus Author ID
56353055800

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Effects of Surface Finish on Sn-3.0Ag-0.5Cu Solder Joint Microstructure and Strength

2021-03-01 , Siti Farahnabilah Muhd Amli , Mohd Arif Anuar Mohd Salleh , Mohd Izrul Izwan Ramli , Nurul Razliana Abdul Razak , Yasuda H. , Chaiprapa J. , Nogita K.

The effects of copper organic solderability preservative (Cu-OSP) and electroless nickel immersion gold (ENIG) surface finish reflowed on Sn-3.0Ag-0.5Cu (SAC305) solder have been investigated in detail. Besides conventional cross-sectional microstructure observation, advanced characterization techniques such as synchrotron radiography imaging and synchrotron micro-x-ray fluorescence (µ-XRF) were utilized to elucidate the microstructural evolution in the solder joints during soldering. Additionally, high-speed shear testing was performed to understand the influence of the surface finish on the solder joint strength. The results indicated that the presence of nickel (Ni) from the ENIG surface finish decreased the growth rate but increased the amount of small Cu6Sn5 primary intermetallics, resulting in a slight reduction of the average interfacial intermetallic compound (IMC) thickness in the SAC305/ENIG solder joints. Due to the refined control of the solder joint microstructure, the average high-speed shear strength was higher for as-reflowed SAC305/ENIG versus SAC305/Cu-OSP solder joints. These results indicate a significant influence of the surface finish on SAC305 solder joint microstructure and strength and could provide a basis to improve solder joint strength.

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Controlling porosity during transient liquid phase bonding for high-temperature soldering processes

2023-01-01 , Nurul Razliana Abdul Razak , Tan X.F. , McDonald S.D. , Bermingham M.J. , Venezuela J. , Nishimura T. , Nogita K.

Exploiting the growth rate dependency of intermetallic compounds (IMCs) on the substrate composition, the possibility of controlling porosity during transient liquid phase (TLP) bonding via a composition gradient is investigated. A Cu substrate with a variable Ni concentration was prepared through selective electroplating and subsequent heat treatment. When this substrate reacted with a molten Sn-rich alloy, there was a non-uniform growth of the Cu6Sn5 IMC. It is proposed that by tailoring the direction of the composition gradient in the substrate, the IMC growth rate can be controlled in such a way as to progressively move the solid-liquid front to redistribute any porosity away from the central region of the joint and thereby improve reliability.

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Microstructure, thermal behavior and joint strength of Sn-0.7Cu-1.5Bi/electroless nickel immersion gold (ENIG)

2021-01-01 , Teoh Ai Ling , Mohd Arif Anuar Mohd Salleh , Dewi Suriyani Che Halin , Foo Kai Loong , Nurul Razliana Abdul Razak , Yasuda H. , Nogita K.

This paper details an investigation into the microstructure, thermal behaviors and joint strength of Sn-0.7Cu-1.5Bi solder alloy on electroless nickel immersion gold (ENIG) surface finish. Besides conventional techniques, the real-time synchrotron imaging was used to analyze the microstructure evolution in Sn-0.7Cu-1.5Bi/ENIG. This research investigated the growth behavior of the primary (Cu,Ni)6Sn5intermetallic compounds (IMCs) in the solder joint with the Bi alloying. The elemental distribution analysis showed the Ni diffused from the ENIG surface finish and dissolved into the bulk solder during solidification and that the size of the primary (Cu,Ni)6Sn5IMCs decreased due to the addition of 1.5 wt% Bi. The average kinetic growth rate of the primary (Cu,Ni)6Sn5IMCs in Sn-0.7Cu-1.5Bi/ENIG was lower than that of the Sn-0.7Cu/ENIG. The thermal analysis revealed that the pasty range slightly increased and the undercooling degree decreased due to the addition of 1.5 wt% Bi for free-standing solder and soldering on ENIG surface finish. The shear strength of the Sn-0.7Cu-1.5Bi/ENIG was determined using a high-speed bond tester, and it increased by ~12% at bulk solder fracture of ~15% within the solder joint interfacial fracture due to the addition of 1.5 wt% Bi into the Sn-0.7Cu. These occurrences can be attributed to the solid solution strengthening effect at the bulk solder and the formation of finer interfacial (Cu,Ni)6Sn5IMCs within the solder joints. The results indicated that the microstructural changes, especially the size reduction of IMCs, in Sn-0.7Cu-1.5Bi/ENIG impacted the joint strength.

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