Study and Improvement on Tungsten Plug Corrosion in CMP Process for PCRAM

Author

Ying Li ; Zhitang Song ; Bo Liu ; Guanping Wu ; Songlin Feng

Author_Institution

State Key Lab. of Functional Mater. for Inf., Shanghai Inst. of Micro-Syst. & Inf. Technol., Shanghai, China

Volume

27

Issue

1

fYear

2014

fDate

Feb. 2014

Firstpage

38

Lastpage

42

Abstract

To reduce the reset current for developing reliable high density phase change random access memory (PCRAM), small bottom electrode contact (BEC) size formation is a critical process. One of the failure mode for the process is the corrosion of tungsten plug, which is caused by tungsten chemical mechanical planarization (CMP) process. In this paper, this CMP process was analyzed. The tungsten polishing step process was characterized by the coefficient j and it shows good performance in tungsten polishing process. The alkali and acidic buff slurry effect on tungsten plug performance were studied. The result shows that the recess free tungsten plug had been fabricated with acidic buff slurry. The electric results confirm that it can fulfill the set operation of PCRAM cells.

Keywords

chemical mechanical polishing; electrochemical electrodes; failure analysis; phase change memories; planarisation; slurries; tungsten; BEC; CMP process; PCRAM; W; acidic buff slurry effect; alkali buff slurry effect; bottom electrode contact; chemical mechanical planarization; failure mode; phase change random access memory; size formation; tungsten plug corrosion; tungsten polishing step process; Corrosion; Films; Phase change random access memory; Plugs; Resistance; Slurries; Tungsten; Chemical corrosion; chemical mechanical planarization; phase change memory; tungsten polishing;

fLanguage

English

Journal_Title

Semiconductor Manufacturing, IEEE Transactions on

Publisher

ieee

ISSN

0894-6507

Type

jour

DOI

10.1109/TSM.2013.2295163

Filename

6689345