Title :
Low Cost UBM for Lead Free Solder Bumping with C4NP
Author :
Ruhmer, Klaus ; Laine, Eric ; Hauck, Karin ; Manessis, Dionysios ; Ostmann, Andreas ; Toepper, Michael
Author_Institution :
SUSS MicroTec Inc., Waterbury
Abstract :
This paper analyzes electroless Ni/immersion Au (ENIG), with and without Pd, as an alternative UBM structure. Wafers were fabricated with these UBM structures, solder applied with C4NP, and chip level stressing performed to determine the robustness of these alternative stack-ups. Analysis of these structures following multiple reflows and thermal cycling is presented. In addition, the paper also reviews production cost analysis for various UBM stackups and solder bump processes, based on a specifically developed cost model. The ENIG UBM structures in combination with C4NP solder bumping provide a significant cost reduction over alternative structures.
Keywords :
cost reduction; gold; metallisation; nickel; soldering; solders; C4NP; NiAu; UBM stackups; chip level stressing; controlled collapse chip connection-new process; electroless nickel-immersion gold structure; lead free solder bumping process; low cost under bump metallurgy structure; multiple reflows conditions; production cost analysis; thermal cycling; wafer fabrication; Adhesives; Costs; Environmentally friendly manufacturing techniques; Gold; Intermetallic; Lead; Metallization; Nickel; Thermal stresses; Tin;
Conference_Titel :
High Density packaging and Microsystem Integration, 2007. HDP '07. International Symposium on
Conference_Location :
Shanghai
Print_ISBN :
1-4244-1253-6
Electronic_ISBN :
1-4244-1253-6
DOI :
10.1109/HDP.2007.4283564
