Bonding interface materials evolution of intermediate In/Ag layers for low temperature fluxless solder based MEMS wafer level packaging

Author

Lee, Chengkuo ; Yu, Daquan ; Yu, Aibin ; Yan, Liling ; Wang, Haitao ; Lau, John H.

Author_Institution

Dept. of Electr. & Comput. Eng., Nat. Univ. of Singapore, Singapore

fYear

2008

fDate

22-24 Oct. 2008

Firstpage

216

Lastpage

219

Abstract

In this paper, we proposed new intermediate bonding layers (IBLs) of Ag-rich composition in In-Ag solder systems in contrast to previous studies mainly based on eutectic composition. The intermetallic compounds (IMCs) at the bonding interface were investigated with respect to the bonding condition, post-bonding room temperature storage and post-bonding heat treatment. The IMCs of Ag₂In and Ag₉In₄ with high temperature resist to post-bonding process are derived under process condition of wafer bonding at 180degC, 40 mins and subsequent 120degC~130degC annealing for 24 hours. Based on our results, we can design proper packaging process flow so as to get reliable wafer level packaged MEMS devices.

Keywords

annealing; circuit reliability; heat treatment; indium alloys; micromechanical devices; silver alloys; solders; wafer bonding; wafer level packaging; Ag₂In; Ag₉In₄; MEMS wafer level packaging; annealing; bonding interface materials; eutectic composition; fluxless solder; intermediate bonding layers; intermetallic compounds; post-bonding heat treatment; post-bonding room temperature storage; temperature 180 degC; temperature 293 K to 298 K; time 24 h; time 40 min; wafer bonding; Annealing; Heat treatment; Intermetallic; Micromechanical devices; Packaging; Process design; Resists; Temperature; Wafer bonding; Wafer scale integration;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronic Materials and Packaging, 2008. EMAP 2008. International Conference on

Conference_Location

Taipei

Print_ISBN

978-1-4244-3620-0

Electronic_ISBN

978-1-4244-3621-7

Type

conf

DOI

10.1109/EMAP.2008.4784267

Filename

4784267