A low temperature vacuum thin film deposition process extensively use in the semiconductor industry due to its ability to apply coatings on surfaces that would not be able to withstand the temperatures of more conventional CVD processes is implemented in TNL-PECVD Simulator.
Major difference between conventional CVD and PECVD processes is that CVD applies heat to the substrate to be coated and chemical kinetics in gas and surface phase reactions drive by temperature. Whereas, PECVD process is usually performed in pressures 0.1 Torr, allowing for relatively low substrate temperatures of room temperature to 350°C. By utilizing plasma to drive chemical reactions kinetics and responsible for stronger bonding.
A single-wafer parallel electrode
PECVD process with showerhead architecture
Characterization of the physico-chemical phenomena including glow discharge chemistry,
Material to be coated amorphous silicon, SiO2, Si3N4 and SiC
Impact of RF powers on plasma density in an Ar/O2 mixture
Plasma use as a continuum medium,
Physical properties of the gases are constant,
Negligible volume change of the reacting gases,
Azimuthal reactor geometry,
The steps details of PECVD processes
Gas stream is fed through the showerhead by a consisting of Precursors and inert gases.
Flow rate & composition of influent gas stream is treated uniform throughout the showerhead.
An RF (radio frequency) power source generate the plasma
Transportion via convection & diffusion to the surface of the wafer.
Steady-state electron density profile due to diffusion-controlled discharge
Electron density depends on plasma volume, radius of the reactor and the effective electric field
Reactions that take place on the bulk plasma
Diffusion coefficients of the radicals and precursors based on Lennard-Jones potential
Point defects, e.g. vacancies, interstitial extraction
| Reactions |
Rate Constant(k) |
Units |
|
|---|---|---|---|
| SiH4 + e- ↔ SiH2 + 2H + e- | 1.8E-11 | s-1cm3 | SiH4 + e- ↔ SiH3 + H + e- | 1.59E-11 | s-1cm3 | SiH4 + H ↔ SiH3 + H2 + e- | 1.325E12 | s-1mol-1cm3 | SiH3 + SiH3 ↔ SiH4 + SiH2 | 9.033E13 | s-1mol-1cm3 | SiH4 + SiH2 ↔ Si2H6 | 2.83E13 | s-1mol-1cm3 |
The coupled algorithms of the gas- & surface phase plasma enhaced reactions kinetics with kMC method
is use to optimize the PECVD processes and calibrate against the experimental findings.
To reduce the film thickness nonuniformity
TNL-PECVD simulator can be used to develop a closed loop operation strategy to improve thinfilms
quality and to reduce the batch-to-batch variability.
Dependence of chemical kinetics on RF voltages can be optimized
Reduction in manpower consumption and growth process cost.
Help to expedite the development to production time associated with new growth process
More details