Wafer-level AuSn and CuSn bonding for MEMS encapsulation

Author

Suni, T. ; Xu, Hao ; Vuorinen, V. ; Heikkinen, H. ; Vahanen, S. ; Jaakkola, Anttoni ; Monnoyer, P. ; Paulasto-Krockel, M.

Author_Institution

VTT Tech. Res. Centre of Finland, Espoo, Finland

fYear

2013

fDate

9-12 Sept. 2013

Firstpage

1

Lastpage

5

Abstract

In this work we have studied AuSn and CuSn Solid-Liquid Interdiffusion (SLID) bonding that can be used for wafer-level encapsulation. SLID bonding of these metal structures takes place at temperatures around 300°C but show higher re-melting temperatures because of the solid-liquid intermetallic phase transformation. 6" silicon wafers were bonded with 60 μm wide, electroplated, AuSn and CuSn seal ring structures. Wafer bonding temperature was varied between 300°C and 450°C, the used bonding force was 3.5 kN under the ambient pressure less than 1×10^-3 mbar. The bonding quality was evaluated with different seal ring metal structures and bonding parameters.

Keywords

bonding processes; copper alloys; diffusion; electroplating; encapsulation; gold alloys; melting; micromechanical devices; seals (stoppers); tin alloys; wafer level packaging; AuSn; MEMS encapsulation; SLID; bonding quality; electroplating; seal ring metal structures; size 60 mum; solid-liquid interdiffusion bonding; solid-liquid intermetallic phase transformation; temperature 300 degC to 450 degC; wafer level bonding; Bonding; Chemistry; Copper; Gold; Scanning electron microscopy; Seals; Tin; MEMS encapsulation; SLID bonding; Wafer level packaging; copper-tin bonding; gold-tin bonding;

fLanguage

English

Publisher

ieee

Conference_Titel

Microelectronics Packaging Conference (EMPC) , 2013 European

Conference_Location

Grenoble

Type

conf

Filename

6698598