Low-Temperature Oxide Wafer Bonding for 3-D Integration: Chemistry of Bulk Oxide Matters

Author

Wei Lin ; Shi, Li-Hua ; Yiping Yao ; Madan, A. ; Pinto, Tiago ; Zavolas, Nick ; Murphy, R. ; Skordas, Spyridon ; Iyer, Srikrishna

Author_Institution

Int. Bus. Machines, Albany Nanotech, Albany, NY, USA

Volume

27

Issue

3

fYear

2014

fDate

Aug. 2014

Firstpage

426

Lastpage

430

Abstract

The effect of bulk chemistry of deposited oxide materials on the eventual wafer bonding energy was fundamentally studied. Although low-temperature silicon oxide (LTO) and tetraethyl orthosilicate (TEOS) exhibited the same bulk density, and nitrogen plasma generated a higher degree of surface activation for TEOS than LTO, using LTO as the bonding oxide resulted in a much higher bonding energy than TEOS. This was attributed to the relatively high percentage of hydrogen-bonded silanol groups in LTO, which pointed to the existence of fine defect areas in LTO that would better accommodate the water molecules generated later by the interfacial condensation reactions. A pre-bonding baking step was found favorable for LTO wafer bonding.

Keywords

silicon compounds; three-dimensional integrated circuits; wafer bonding; 3D integration; LTO wafer bonding; SiO₂; TEOS; bulk chemistry effect; bulk density; bulk oxide matter chemistry; deposited oxide materials; hydrogen-bonded silanol groups; interfacial condensation reactions; low-temperature oxide wafer bonding; low-temperature silicon oxide; nitrogen plasma; pre-bonding baking step; surface activation; tetraethyl orthosilicate; wafer bonding energy; water molecules; Bonding; Plasma temperature; Silicon; Surface treatment; Three-dimensional displays; Wafer bonding; 3-D integration; wafer bonding;

fLanguage

English

Journal_Title

Semiconductor Manufacturing, IEEE Transactions on

Publisher

ieee

ISSN

0894-6507

Type

jour

DOI

10.1109/TSM.2014.2323941

Filename

6823726