How does the Diener Tetra 45 work?
In the CCP etch system, parallel plate electrodes are excited by a continuous radio frequency (RF, 13.56 MHz) power supply. This creates an alternating electric field perpendicular to the electrodes. This electric field accelerates apart from electrons, also the ions that have been generated, towards the electrodes, which makes plasma formation (dissociation and ionization) and ion acceleration (sheath potential) directly coupled. Increasing the power not only increases the plasma density, but also the self-bias voltage and thus the ions’ energy. As a result, plasma density and ion energy are coupled and cannot be changed independently. In CCP, the ion energy can reach several hundred eV. The operating gas pressure of the system is between 0.01 – 0.6 mbar. In the range 0,01 – 0,03 mbar reactive ion etching (RIE) of Si or SiO2 by SF6 or mixtures SF6/O2 and CF4/O2 can be achieved. Etching of Si3N4 by CHF3/O2 mixtures can be achieved. In the same pressure range Ar processing can also take place. In the range of 0,2 – 0,6 mbar the etching of Si3N4 is possible by using CF4.
Gasses that can be used with the Diener Tetra 45 plasma etcher:
Recommended gasses are: H2, He, N2, O2, Ar, Air, CF3, CF4, CHF3, NF3, SF6 and mixtures of CF4/H2.
Most Flourine containing gasses can potentially be used.
Additional requirements must be discussed with the manufacturer.
Chamber cleaning is recommended to be carried out once a month using a mixture of CF4/O2 (10%/90%) for a few hours at low power (3-50%) and at 0.2-0.3 mbar pressure.
Gasses that are prohibited to us with the Diener Tetra 45 plasma etcher:
Gasses containing chlorine, bromine or iodine are strictly prohibited due to the risk of degradation of the valves in the vacuum pumps.
Al is usually etched by gasses containing Chlorine and thus materials containing Al cannot be processed by this system.