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Title:	An investigation on mechanical properties of tin-silver copper and tin-silver lead-free solder sphere used in FCPBGA electronic packages
Authors:	Wong Tzu Ling (P40763)
Supervisor:	Nowshad Amin, Assoc. Prof. Dr.
Keywords:	Flip chip technology Copper Electronic packaging Universiti Kebangsaan Malaysia -- Dissertations Dissertations, Academic -- Malaysia
Issue Date:	2-Aug-2012
Description:	In the recent years, lead-free solder material has been increasingly applied to the green semiconductor products for RoHS compliance. Among the mass production lead-free solders, the Tin-Silver-Copper (SnAgCu) family solder materials have been widely used as solder ball alloy for Ball Grid Array products. In manufacturing, Sn4.0Ag0.5Cu family which includes Sn3.8Ag0.7Cu solder ball alloy is the conventional solder material commonly used for Ni/Au pad finishing, including electrolytic or Electroless Nickel Immersion Gold (ENIG). For Flip Chip Plastic Ball Grid Array (FCPBGA), due to the black pad issue inherent in ENIG pads, recent industry trend has changed from ENIG pad finishing to solder-on-pad (SOP) pad finishing, thus improving board level reliability. A typical SOP solder is Sn3.0Ag0.5Cu. However, SOP has posted a challenge in ball attachment process due to higher oxide level on SOP pads. In this study, the mechanical properties and performance of Sn3.5Ag and Sn3.8Ag0.7Cu (SAC387) solder ball on 31x31 FCPBGA with solder on pad (SOP) was investigated. Sn3.5Ag solder was investigated to replace the Sn3.8Ag0.7Cu solder as it is able to resolve the wrinkled surface and ball dropped issue after assembly. Cold ball pull (CBP) and nanoindentation analysis were used to evaluate the solder joint strength under two different conditions, namely after assembly (T0) and after Moisture Sensitivity Level 3/260°C test (MSL3). In addition, tray drop test and packing drop test were conducted to assess solder joint integrity due to handling and impact force. Cross sectioning was also performed under all conditions for intermatellic compound (IMC) measurement and microstructure study. The result shows that Sn3.5Ag solder sphere has demonstrated good CBP and drop test result compared to Sn3.8Ag0.7Cu solder sphere. Furthermore, Sn3.8Ag0.7Cu exhibits higher hardness and IMC thickness after MSL3. Thus Sn3.5Ag is to be recommended for the replacement of conventional solders present used in electronic manufacturing industry.,Master of Science,Certification of Master's / Doctoral Thesis" is not available"
Pages:	85
Call Number:	TK7870.16.W643 2012 3 tesis
Publisher:	UKM, Bangi
Appears in Collections:	Faculty of Engineering and Built Environment / Fakulti Kejuruteraan dan Alam Bina

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