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

fYear

2007

fDate

26-28 June 2007

Firstpage

1

Lastpage

7

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;

fLanguage

English

Publisher

ieee

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

Type

conf

DOI

10.1109/HDP.2007.4283564

Filename

4283564