Title :
Alternative lead-free solder joint integrity under room temperature mechanical load
Author :
Geng, Phil ; Aspandiar, Raiyo ; Byrne, Tony ; Pon, Florence ; Suh, Daewoong ; Mcallister, Alan ; Nazario, Arnaldo ; Paulraj, Prawin ; Armendariz, Norman ; Martin, Ted ; Worley, Tom
Author_Institution :
Intel Corp., Hillsboro, OR, USA
Abstract :
This work explored the feasibility of using alternative lead-free solder alloy with lower melting temperatures as board-level interconnects and attempted to establish preliminary baseline reliability under mechanical loads. Solder ball pull and shear tests were first performed at package level. Bend tests were performed at board level with PCB/BGA test coupons under monotonic three-point bending load. In addition to the traditional Sn-Pb solder and current lead-free Sn-Ag-Cu solder, four other lead-free solders (Sn-In, Sn-Bi, Sn-Bi-Ag and Sn-Zn-Al) were tested. For the board level test, surface finishes were immersion silver (ImAg) and organic solderability preservatives (OSP) with package level surface finish of electrolytic Ni and electrolytic Au. The test coupon with surface mounted BGAs has both via-in-pad (VIP) pads and non-VIP pads. The pull, shear and bend test results showed that Sn-In solder has the lowest performance, while Sn-Bi and Sn-Bi-Ag solder compositions showed comparable performance to Sn-Ag-Cu. The work showed that Sn-Zn-Al solder could be a potential choice for lead-free solder alternative. Bend test showed that most of the BGAs with non-VIP pads performed better than those with VIP pads.
Keywords :
aluminium alloys; ball grid arrays; bending strength; bismuth alloys; chip scale packaging; circuit reliability; copper alloys; ductility; failure analysis; indium alloys; integrated circuit interconnections; mechanical testing; printed circuit testing; reflow soldering; shear strength; silver alloys; surface finishing; surface mount technology; tin alloys; zinc alloys; 293 to 298 K; OSP; PCB/BGA test coupon; SnAgCu; SnBiAg; SnBiAg solder; SnIn; SnIn solder; SnPb solder; SnZnAl; SnZnAl solder; baseline reliability; bend test; board level interconnects; board level test; electrolytic Au; electrolytic Ni; immersion silver; lead free SnAgCu solder; lead free solder alloy; lead free solder joint integrity; mechanical load; melting temperature; monotonic three point bending load; organic solderability preservative; package level test; room temperature; shear test; solder ball pull; surface finishing; surface mounted BGA; via-in-pad; Environmentally friendly manufacturing techniques; Gold; Lead; Packaging; Performance evaluation; Silver; Soldering; Surface finishing; Temperature; Testing;
Conference_Titel :
Thermal and Thermomechanical Phenomena in Electronic Systems, 2004. ITHERM '04. The Ninth Intersociety Conference on
Print_ISBN :
0-7803-8357-5
DOI :
10.1109/ITHERM.2004.1318297
