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1770994 
Journal Article 
Process development of high-k metal gate aluminum CMP at 28 nm technology node 
Hsien, YH; Hsu, HK; Tsai, TC; Lin, W; Huang, RP; Chen, CH; Yang, CL; Wu, JY 
2012 
1 
Microelectronic Engineering
ISSN: 0167-9317 
92 
19-23 
WOS:000303084700005 
The replacement metal gate (RMG) height range and
defectivity (fall on particle, Al residue, corrosion and micro-scratch) performance controls are
very challenging for high-k metal gate (HKMG) RMG chemical mechanical polishing (CMP) processes.
In this study, a robust aluminum metal CMP (Al-CMP) process development was investigated to meet
the criteria of RMG at 28 nm technology node. The Al metal gate height loss post-Al-CMP was found
to increase with increasing the total area and pattern density of metal gates. Adding at least
one extra ghost metal gate dummy structure on both sides of each metal gate and optimizing the
metal gate dummy structure can effectively eliminate the metal gate height loss. Furthermore,
implementing a real-time profile control (RTPC) end-point detecting system with lower down force
polishing condition can further reduce the Al metal gate height loss and range levels. The
defectivity issues of the microscratches and fall on particles can be fixed by using a soft pad
with chemical wafer buff process on the final Al-CMP polishing step. (C) 2011 Elsevier B.V. All
rights reserved. 
RMG; HKMG; Al-CMP; Metal gate height loss; RTPC; Defect improve