8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 








 

 

 

 

 

 

 


 

N
E
W
S
L
E
T
T
E
R


 

Modeling the Effect of Bumpy Abrasive Particles on Chemical-Mechanical Polishing

Clarkson Distinguished Professor Goodarz Ahmadi and his group are modeling the effect of bumpy abrasive particles on the chemical-mechanical polishing process. In this study, the effect of course surface roughness of abrasive particles on the removal rate in CMP is being analyzed. For this work, the mechanical contact theory is being used to determine the relationship between the polishing rate and the properties of the pad, the wafer and the abrasive particle. Particular attention is given to the case that the abrasives are compact bumpy particles and the pad is soft. Results show that the polishing rate depends on the size of the abrasive particle bumps.  

CAMP'S SEVENTH CMP SYMPOSIUM

The penetration depth of bumpy particles is larger than that of spherical particles of the same diameter. However, the removal rate by the abrasive wear mechanism for bumpy particles is less than that for the corresponding smooth spherical particles. For more information, see the following reference: Mazaheri, Ali R. and Ahmadi, Goodarz, "Modeling the Effect of Bumpy Abrasive Particles on Chemical-Mechanical Polishing," Journal of the Electrochemical Society, 149, G370 (2002).

Modeling the Effect of Colloidal Forces on Chemical-Mechanical Polishing

Clarkson Distinguished Professor Goodarz Ahmadi and his group are preparing a model for the effect of colloidal forces on CMP. It is well known that the variation of slurry pH could significantly affect the chemical-mechanical polishing process. In this study, a particle-scale mechanical model for the surface removal rate (that includes the double layer forces of abrasives and the wafer surface) is being developed. Results show that the van der Waals force and the electrical double layer attraction and repulsion play a major role in the chemical-mechanical polishing process. Furthermore, the magnitudes and signs of the zeta potential of the surface and the abrasives significantly affect the removal rates. The results show that the removal rate increases sharply in cases where the zeta potentials of the surface and abrasive have an opposite sign. On the other hand, the removal rate decreases when the zeta potentials have the same sign. The removal rates for the polishing of tantalum with silica and alumina abrasives were compared with the available data and qualitative agreements were observed.

. CAMP'S SEVENTH CMP SYMPOSIUM

The CAMP newsletter is published four times per year by the Center for Advanced Materials Processing, a NYSTAR-designated Center for Advanced Technology located at Clarkson University.
Editor: Dana M. Barry.
Equal Opportunity Policy. Clarkson University does not discriminate on the basis of race, gender, color, creed, religion, national origin, age, disability, sexual orientation, veteran or marital status in provision of educational opportunity or employment opportunities and benefits.

Center for Advanced Materials Processing
Clarkson University
Box 5665 Potsdam,
New York 13699-5665

S.V. Babu, Director & Vice Provost (babu@clarkson.edu)
Edward P. McNamara, Deputy Director
 (mcnamara@clarkson.edu)

Phone: 315-268-2336, FAX: 315-268-7615, e-mail: leila@clarkson.edu
web site: http://www.clarkson.edu/camp

----------------------------------------------------------------------------------------------------------------------

TOP

PREVIOUS PAGE
INDEX PAGE

Page
8
----------------------------------------------------------------------------------------------------------------------

Webmaster: Urmi Roy (Rini)
e-mail: urmi@clarkson.edu