Via-Shape-Control for Copper Dual-Damascene Interconnects With Low-k Organic Film

Author

Kinoshita, Keizo ; Tada, Munehiro ; Hiroi, Masayuki ; Shiba, Kazutoshi ; Onodera, Takahiro ; Tagami, Masayoshi ; Saitoh, Shinobu ; Hayashi, Yoshihiro ; Usami, Tatsuya ; Kikkawa, Takamaro

Author_Institution

Syst. Devices Res. Labs., NEC Corp., Kanagawa

Volume

21

Issue

2

fYear

2008

fDate

5/1/2008 12:00:00 AM

Firstpage

256

Lastpage

262

Abstract

Copper dual-damascene (DD) interconnects are fabricated with low-k organic film (SiLKtrade) without any etch-stop layers by use of dual hard mask (dHM) process combined with sidewall-hardening etching step. It is a key point to reduce shoulder loss during trench etching at connecting regions of vias and trenches, so that hardening of the via-sidewall by fluorocarbon plasma during via etching is implemented. Careful designs of dual hard mask structures and their patterning sequence are carried out for the process without etch-stop layer under the trench. The two-layered interconnect with low-k structure has achieved low via-resistance of 0.65 Omega at 0.28 mumOslash with keeping large tolerance of misalignment up to 0.1 mum.

Keywords

copper; etching; hardening; integrated circuit interconnections; integrated circuit metallisation; low-k dielectric thin films; masks; organic compounds; Cu; copper dual-damascene interconnects; dual hard mask process; fluorocarbon plasma; low-k organic film; patterning; sidewall-hardening etching step; tolerance; trench etching; Copper; Delay; Dielectric materials; Etching; Inorganic materials; Large scale integration; Organic materials; Plasma applications; Plasma sources; Ultra large scale integration; Dual damascene; etching; low-k; shoulder loss;

fLanguage

English

Journal_Title

Semiconductor Manufacturing, IEEE Transactions on

Publisher

ieee

ISSN

0894-6507

Type

jour

DOI

10.1109/TSM.2008.2000268

Filename

4512070