addition Professor Subramanian is working with doctoral student
Qingjun Qin on developing theoretical descriptions of various aspects
of polishing in an orbital polishing tool. A SpeedFam/IPEC 676 orbital
tool is available at Clarkson for testing predictions from these
modeling efforts. Experiments have been performed on the polishing
of blanket copper films deposited on 200 mm silicon wafers, using
an abrasive-free chemical solution for material removal. In these
experiments, the concentration of the chemical and the orbital speed
were both varied, and the variation of material removal rate was
measured as a function of radial position on the wafer in each case.
One of the objectives of the model is to predict these radial variations
of removal rate. The pad is constructed with a rectangular grid
of grooves, and the slurry is introduced from underneath the pad
through a set of 61 holes that are located at the intersections
of selected grooves. The model involves describing the flow behavior
in the groove structure of the pad, and combining this description
with a model of the relative motion of each point on the wafer relative
to the pad, along with a convective diffusion model for the transport
of the chemical species in the grooves.
Distinguished Professor Goodarz Ahmadi
and his group are developing a model (based on mechanical contact
theory) for the chemical-mechanical polishing process. The goal
of their research is to provide a fundamental understanding of the
parameters that control the effectiveness of CMP for surface planarization.
Their current work focuses on the abrasive particle, wafer, and
pad contact and the abrasive and adhesive wear mechanisms in the
chemical-mechanical polishing process. They are developing a model
for interactions of pad asperities with abrasive particles and the
wafer. Their analysis includes the influence of abrasive particle
adhesion to the surface of the wafer. Also they are looking at the
CMP process using hard and soft pads and dilute and concentrated
slurries. In addition Professor Ahmadi and his students are studying
the effect of abrasive particle shapes, slurry pH, and colloidal
forces on the removal rate.
model predictions are described in detail and compared with the
available semi-empirical correlations in the paper " A Model for
Mechanical Wear and Abrasive Particle Adhesion During the Chemical-Mechanical
Polishing Process," by G. Ahmadi and X. Xia, Journal of the Electrochemical
Society , 148 (3) G99-G109 (2001).
of the Seventh International Symposium on Chemical-Mechanical
Polishing. From left: Vice Provost/CAMP Director S.V. Babu
and Dr. Manabu Tsujimura of Ebara Corporation.
Sponsors Seventh International Symposium on Chemical-Mechanical
sponsored its seventh very successful International Symposium
on Chemical-Mechanical Polishing. The four-day symposium/workshop
held (August 11 - 14, 2002) at the Hilton Resort in Lake Placid,
New York, attracted over 100 participants from around the
world. Attendees were from the United States, Japan, and other
Countries. This meeting was co-chaired by Dr. Manabu Tsujimura
(Ebara Corporation), Dr. Dan Heenan (IBM), and Vice Provost/CAMP
Director S.V. Babu. It included presentations by industrial
and university representatives and a poster session displaying
CAMP's research activities on CMP. CAMP's Eighth International
Symposium on Chemical-Mechanical Polishing will be held at
the Hilton Resort in Lake Placid, NY (August 10-13, 2003).
- Laboratory Short Course
"Use of Surfactants in Microelectronic
Clarkson University Potsdam, New York May 5-8, 2003
Annual Technical Meeting Gideon-Putnam Hotel
& Conference Center
Saratoga Springs, New York
May 14-16, 2003
Course on Nuclear Magnetic Resonance (NMR)
Clarkson University Potsdam, New York
July 7-11, 2003
Eighth International Symposium on Chemical-Mechanical Polishing
Hilton Resort Lake Placid, New York
August 10 - 13, 2003
information about CAMP industrial short courses, please
call Professor Richard Partch at 315-268-2351 or send email
to him at firstname.lastname@example.org).
on these and other CAMP events, is available at the CAMP
website at http://www.clarkson.edu/camp.