Diffusion behavior and reliability in bonds between Au-Ag alloy and aluminum

Tomohiro Uno, Kohei Tatsumi

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The replacement of conventional pure Au bonding wires by highly-alloyed Au-Ag ones in LSI semiconductors can reduce significantly material cost. However, Au-Ag wires have not yet been used due to a failure problem at the bonding points between the Au-Ag balls and Al thin film pads. Therefore, to apply Au-Ag wires to LSI products, the improvement of the thermal reliability at the bonding points between Au-Ag/Al is very important. The thermal reliability of the Au-Ag/Al bonds depends on the Ag concentration (CAg) in Au wires. A certain range of CAg showing good bond reliability was found. Ball bonds of Au-14 at%Ag produced a significant degradation after annealing. On the contrary, bonds of Au-24 at%Ag provided as good a reliability as the commercial pure Au wire after annealing at 473 K for 1000 hr. Thus, the optimization of the Ag concentration in the Au-Ag alloy wires was significantly effective in improving the bond reliability. Diffusion behavior at the bond interface of the Au-Ag/Al was different from that of pure Au/Al. It was characteristic that AuAl2 grew predominantly in the interface of the Au-Ag/Al. The formation of intermetallic compounds varies with CAg. The dependence of the intermetallic compounds (Au5Al2, AuAl2, Ag2Al) on the Ag concentration dominated the bond reliability.

Original languageEnglish
Pages (from-to)1545-1554
Number of pages10
JournalNippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals
Volume63
Issue number12
Publication statusPublished - 1999 Dec
Externally publishedYes

Fingerprint

Aluminum
wire
Wire
aluminum
large scale integration
Intermetallics
intermetallics
balls
Annealing
annealing
Semiconductor materials
degradation
costs
Degradation
Thin films
optimization
products
thin films
Costs

ASJC Scopus subject areas

  • Metals and Alloys

Cite this

Diffusion behavior and reliability in bonds between Au-Ag alloy and aluminum. / Uno, Tomohiro; Tatsumi, Kohei.

In: Nippon Kinzoku Gakkaishi/Journal of the Japan Institute of Metals, Vol. 63, No. 12, 12.1999, p. 1545-1554.

Research output: Contribution to journalArticle

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