Semiconductor RF Applications

The technology used in semiconductor manufacture within the HDP - CVD environment works mainly because of RF (Radio Frequency) in as chamber with gas, creating a plasma whereby deposition is done on silicon wafers to grow the transistor

Magnetron Plasma

Small electrons, travelling in a straight-line path, have low probability of impacting with a gas particle, so ion density is relatively low.
Adding magnetic fields, forces the electrons into a helical cloud, increasing the likelihood of an ionizing collision by a factor of 10.

High Density Plasma (HDP)

Conventional plasmas are of the "low density" variety.
About one charged particle created for every million neutral particles.
Modern IC process requirements have led to the development of “high-density” plasmas.
An order of magnitude greater density of charged particles.Capable of operating at much lower pressures.This technology enables highly directional processes.
HDP CVD systems are used to fill deep trenches.
HDP etch systems are used to create very high aspect ratio contacts.

Two significant high density plasma sources:
Electron Cyclotron Resonance (ECR)
Inductively Coupled Plasma (ICP)

Electron Cyclotron Resonance (ECR)

Couples Together: an electric field operating at microwave frequency a steady-state magnetic field
This creates a resonance condition that causes the electrons to become highly energized.
A greater ionization rate is the result.

Used for anisotropic etching of sub 0.25m features.

Capacitively Coupled Plasma (CCP)

All plasmas discussed up to this point have been "capacitive coupled" variety.
Capacitively coupled plasmas (CCP) use RF power applied to parallel-mounted electrodes to create an RF electric field inside the chamber.

Inductively Coupled Plasma (ICP)

Electrons are mobilized by a magnetic field; they move at right angles to the direction of the magnetic field.
An ICP reactor makes use of RF Power applied to a coil of wire wrapped around the outside of a plasma chamber.
The coil (or inductor) creates a magnetic field inside the chamber, which induces the motion of electrons inside the chamber.

Inductively (or Transformer) Coupled Plasma (ICP)

ICP reactors are capable of achieving very efficient power coupling with plasma densities even greater than ECR reactors.
ICP sources are usually used in combination with a lower-power CCP source.
The ICP source generates the desired free radicals and ions upstream of the wafer.
The CCP source controls the flow of the ions to the wafer at a desired rate and energy.

Downstream Plasma Processing

High Density Plasmas create a greater density of active species, but also have greater ion damage to the wafer.
With downstream processing, the plasma is created in an area of the chamber that is removed from the surface of the wafer.
Then the fluid flow of the gasses in the chamber (as determined by the vacuum system) carries the ions and radicals to the wafer surface.