Electromigration characteristics of tungsten plug vias under pulse and bidirectional current stressing

Author

Tao, Jiang ; Young, K.K. ; Pico, Carey A. ; Cheung, Nathan W. ; Hu, Chenming

Author_Institution

Dept. of Electr. Eng. & Comput. Sci., California Univ., Berkeley, CA, USA

Volume

12

Issue

12

fYear

1991

Firstpage

646

Lastpage

648

Abstract

Using Kelvin test structures, electromigration performances of selective CVD tungsten filled vias under DC, pulsed DC, and AC current signals have been studied. The metallization consists of Al-Cu/TiW multilevel metals. The via electromigration lifetime exhibits a current polarity dependence. The via AC lifetimes are found to be much longer (more than 1000*) than DC lifetimes under the same peak stressing current density. The via lifetimes under pulsed DC stress of 50% duty factor are twice the DC lifetimes at low-frequency regions (<200 Hz) and 4-5 times the DC lifetimes at high-frequency regions (>10 kHz). The results are in agreement with the vacancy relation model.<>

Keywords

CVD coatings; VLSI; electromigration; materials testing; metallisation; reliability; tungsten; AC lifetimes; AlCu-TiW metallisation; DC lifetimes; Kelvin test structures; W filled vias; W plug vias; bidirectional current stressing; current polarity dependence; electromigration characteristics; electromigration lifetime; electromigration performances; electromigration resistance; pulse current stressing; pulsed DC stress; selective CVD; stressing current density; vacancy relation model; via lifetimes; Aluminum; Circuit testing; Electromigration; Electrons; Integrated circuit interconnections; Kelvin; Metallization; Plugs; Sputter etching; Tungsten;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/55.116942

Filename

116942