RIE

Principle and app lications

The RIE process (reactive ion etching) is a dry etching process used in electronic and microelectronic manufacturing. Applications are for example fast and ultra high surface cleaning, surface activation, photo-resist stripping and semiconductor etching. 

For this process usually a planar plate reactor is used (see figure 1). After generating a gas atmosphere with a pressure of 10-2 to 10-1 mbar the gas discharge (plasma) is ignited by applying an RF voltage. Caused by the different mobility of light electrons and heavy ions in the electric field, a negative DC potential builds up at the smaller electrode (substrate carrier). This self bias potential usually is about 10 to a few hundred volts. 

The etching effect to the substrate (wafer, PCB etc.) is the sum of at least two processes, a physical and a chemical one:

1. Chemical etching / removal of the substrate surface or contami-nation by reaction with reactive gas particles generated in the plasma (plasma etching).
2. Physical etching of the surface by transfer of direct momentum of heavy ions which are accelerated in the electric field (sputter etching)

The RIE process combines the advantages of both effects - high selectivity, high etching rate and an-isotropic etching.

FEATURES

• Vacuum chamber made of stainless steel or aluminum
• Vacuum pumps for corrosive gases including oil mist filter and oil return system
• Gas inlet system with up to 4 mass flow controllers
• Tailor made gas shower for optimised distribution
• Pressure measurement with capacitive or Pirani gauge (depending on the requirements)
• Impedance matching of the RF power through matching networks with automatic tuning designed and manufactured by AURION
• Power-Split (when using more than one cathode)
• DC bias control for equal bias potential at more than one cathode
• Semiautomatic or PC control including data logging