PLASMA – GLOW DISCHARGE

It’s usually the first process phase that is applied and it’s commonly called “phase of substrate cleaning”.
It’s activated after the equipment has reached a vacuum value among 6x10-2 and 8x10-2 mbar. The function of glow discharge is to activate the substrate surface in order to obtain the best metal adhesion. Substrates made with different kind of material usually require different process parameters.

The glow discharge phase is a plasma that is a partially or totally ionized gas, unstable by nature.
The plasma nature changes, depending on the gas or the mixture gas injected (oxygen, Argon, etc..), the pressure located in the process chamber and the electric field that supports it.
A combination between these three elements generates a substrate with a superficial tension and then with different chemical
and electrostatic combinations.

The glow discharge cathode is located in the centre of the process chamber.
The substrates are placed around the cathode and they are made to rotate (rotation and translation) during treatment phase.
After this, is generated a electric discharge that support the Plasma and that ionizes the gas and then activates the substrates surface.