Fabrication of high-performance on-chip suspended spiral inductors by micromachining and electroless copper plating

Author

Jiang, H. ; Wang, Y. ; Yeh, J.-L.A. ; Tien, N.C.

Author_Institution

Sch. of Electr. Eng., Cornell Univ., Ithaca, NY, USA

Volume

1

fYear

2000

fDate

11-16 June 2000

Firstpage

279

Abstract

Polysilicon spiral inductors encapsulated with copper (Cu) were suspended over 30-/spl mu/m-deep cavities in the silicon substrate beneath. The metallization process simultaneously coated the inner surfaces of the cavities with Cu to form both good radio-frequency (RF) ground and electromagnetic shield. Quality factor (Q) up to 30 and self-resonance frequency (f/sub res/) higher than 10 GHz were achieved for a 10.4 nH inductor. Simulation showed that the Cu-lined cavities reduced the mutual inductance between two adjacent inductors by a factor of 5, compared with that without the cavities. This proves that good shielding was provided by the cavities.

Keywords

MMIC; Q-factor; UHF integrated circuits; copper; electroless deposition; electromagnetic shielding; inductors; integrated circuit metallisation; micromachining; silicon; 10 GHz; 30 micron; Cu encapsulation; Cu-Si; Cu-lined cavities; EM shield; RF ground; Si; Si substrate cavities; electroless Cu plating; electromagnetic shield; fabrication process; metallization process; micromachining; mutual inductance; onchip suspended spiral inductors; polysilicon spiral inductors; quality factor; self-resonance frequency; Copper; Electromagnetic shielding; Fabrication; Inductance; Inductors; Metallization; Q factor; Radio frequency; Silicon; Spirals;

fLanguage

English

Publisher

ieee

Conference_Titel

Microwave Symposium Digest. 2000 IEEE MTT-S International

Conference_Location

Boston, MA, USA

ISSN

0149-645X

Print_ISBN

0-7803-5687-X

Type

conf

DOI

10.1109/MWSYM.2000.860977

Filename

860977