| |
Chemically reacting plasma discharges are an indispensable part of modern
integrated circuit fabrication technology. Working with Kinema
Research and Software , Fluent now provides a tool for modeling plasma
processes in the semiconductor industry. The new software links FLUENT
to Kinema's PLASMATOR ® software and addresses key applications including
plasma-enhanced chemical vapor deposition (PECVD), dielectric and metal
etching, ion implantation, and reactor cleaning. Models for inductively
(ICP) and capacitively (CCP) coupled plasma discharges are included. The
new product gives FLUENT users access to Kinema's unique comprehensive
plasma chemistry database - including collision cross-sections, attachment,
recombination, ionization, and dissociation reactions - by including chemistry
models for key applications.
Electron density, electron temperature, and oxide deposition
rate in a GEC reference cell
Oxygen dissociation distribution in a standard GEC reactor
Inductively coupled plasma sources have the desirable feature of being
able to separately control the flux and energy of the ions incident onto
the wafer. The plasma is generated by a coil (cylindrical or planar) driven
at radio frequencies typically around 13.56 MHz. PLASMATOR is designed
to solve time-dependent fluid equations for electrons and ions self- consistently,
with Poisson's equation for the electric potential. It also computes RF
inductive heating effects from a time- averaged solution of Maxwell's
equations. Comprehensive 3D simulations are often impractical due to the
complicated nature of plasma chemistry, which frequently involves tens
of products and hundreds of reactions. The computations are simplified
by initially exploring the plasma discharge with 2D simulations in PLASMATOR,
which includes an extensive reaction set.
Atomic argon ionization distribution in the GEC reactor
Asymmetrical distribution of silane dissociation (SiH
3 ) in the GEC cell
The results are then used in FLUENT to create a representative reaction
set, which includes only the dominant product ions and neutrals. The representative
reaction set retains sufficient complexity to reproduce the important
behavior of the plasma but is simple enough to allow detailed 3D simulations
of the process reactor. This methodology couples the disparate time scales
of plasma and neutral transport, and allows a fairly complex plasma chemistry
(among electrons, ions, and neutrals) to be included in the simulation.
In addition, the simulations are fast enough to allow design iterations
in an industrial time frame.
"We are very pleased to see Fluent and Kinema joining forces. The coupling
of these two products is important because it combines the CFD expertise
of FLUENT with the comprehensive plasma physics models of PLASMATOR,"
says Larry Gochberg, Manager of Computational Modeling and Reliability
at Novellus Systems, Inc., San Jose, CA. "The integration of these two
tools will aid in improving the accuracy and efficiency of our plasma
CVD modeling work," Gochberg concludes.
The joint FLUENT/PLASMATOR product was showcased at SEMICON West 2000
in July and was released in late 2000.
|
|
|
