Micromachined branch line coupler in CMOS technology

Author

Ozgur, M. ; Kozat, U.C. ; Zaghloul, M.E. ; Gaitan, M.

Author_Institution

Dept. of Electr. Eng. & Comput. Sci., George Washington Univ., Washington, DC, USA

Volume

1

fYear

2000

fDate

11-16 June 2000

Firstpage

291

Abstract

An internally ground-equalized coplanar branch line coupler (BLC) is fabricated by post-processing 2poly/2metal analog CMOS chips. First level metallization is used to equalize the ground planes, hence to suppress the unwanted coupled-slot-line mode propagation. This addition necessitates additional compensation of signal lines to improve the return losses. Fabricated CMOS chips are post-processed with a two-step procedure. First, a thick polyimide film is screen-printed on the devices as a stress-compensation. Then, the silicon substrate is selectively removed underneath the devices. The measured responses show very good agreement with simulations. Fabricated devises exhibit return losses less than 10 dB and maximum of 1 dB amplitude difference in the frequency range of 25-30 GHz.

Keywords

CMOS integrated circuits; coplanar waveguide components; field effect MMIC; integrated circuit metallisation; losses; waveguide couplers; 25 to 30 GHz; CMOS technology; coupled-slot-line mode propagation; first level metallization; internally ground-equalized coplanar branch line coupler; micromachined branch line coupler; polyimide film; return losses; screen-printing; stress-compensation; two-step procedure; CMOS technology; Coplanar waveguides; Educational institutions; Fabrication; Frequency; Impedance; Integrated circuit interconnections; Metallization; Polyimides; Silicon;

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.2000.860983

Filename

860983