Chamber-Clean after Dielectrics Deposition – A case for isotropic microwave plasma
As deposition is one of the pillars of semiconductor production, it depends on a controlled, repeatable and clean environment. One challenge of the deposition process is, that deposition does not only occur on the substrate but also on the chamber walls. This is a permanent threat of particles and contamination. Hence, the complete and repeatable cleaning of the process-chamber is key for layer quality as critical dimensions keep challenging physical limits.
Microwave plasma is the perfect solution for removing such thick coating off the chamber walls. The advantage of microwave (MW) plasma over RF-plasma makes the difference – chamber walls can be cleaned even without direct expose to the plasma source due to its unique property of microwave.
Microwave Plasma – Isotropic and fast clean
When it comes to chamber clean, RF-plasma is not ideal due to its anisotropic properties. As ion bombardment is inherent to RF-plasma, it required direct exposure of the parts to be cleaned. In reality, parts of the chamber walls are hidden to the plasma source which causes incomplete clean and subsequent flaking, particles and low yield. Microwave assisted plasma clean is the solution to this problem. The generated radicals reach hidden and protected areas of the chambers which are invisible to the RF-source.
Muegge remote microwave-plasma addresses these issues
Wide process range
The Muegge remote plasma clean is available for all materials which do not require corrosive chemistry, e.g.:
Advantages of microwave assisted plasma process
Semiconductor manufacturing requires repeatable process conditions and clean process chambers. Microwave-plasma allows to clean fast without eroding sensitive components in the chamber (i.e. electrostatic chuck).
It provides the capability for complete removal of dielectrics and organic layers at high speed (>200 µm/h) and high selectivity with no altering of chamber surfaces. The radicals generated produce chemical reactions at the surface, leading to pure chemical etching at high rates with extremely low thermal load.
Microwave assisted plasma is highly environmentally compliant due to nearly complete dissociation of process gases like CF4.