Dielectric Etch

Dry dielectric etch process consists of selectively removing insulating materials such as oxides on the wafer, forming the insulating structures that protect conducting parts.

As critical dimensions are continuously shrinking, high uniformity and selectivity are needed to meet required electrical performance on such tiny structures: this is achieved by Plasma or Reactive Ions etching process.

Application requirements

  • Vacuum performance stability over time for optimized yield
  • Condensable management by high temperature operation
  • High process lifetime at low operating costs: Low power consumption, low repair cost
  • High capacity & high flow magnetically levitated turbopumps
  • Small footprint dry pumps

How does it work?
Etching gas, commonly Fluorine based, are injected in the reactor. Plasma generates radicals which react on the wafer surface by creating a volatile by-product. Thanks to device patterning obtained by lithography and through control of plasma reaction and temperature, the material is selectively etched from the surface at the desired rate.

Vacuum requirements
Dry dielectric etch processes operate at low pressure, in the range of 10-2 to 10-3 mbar.
In order to maintain a low vacuum, turbopumps are mounted directly on the chamber reactor, backed by primary dry pumps installed in the basement. As gas flows are continuously increasing, required turbopumps pumping capacity vary from 1,600 to 4,000 l/sec on the newest generation reactors. Dry pumps typically require pumping speeds from 600 to 1,200 m3/h.

By-products to be evacuated are condensable, high temperature operation is therefore critical for extended lifetime.

Product portfolio
Pfeiffer Vacuum provides a full range of turbopumps and primary dry pumps designed to handle these challenges. Our magnetically levitated turbopumps ATH M series provide vibration free high vacuum and high temperature / high flow operation. ATH M series are qualified at the major OEMs on the most advanced dielectric etch chambers. Our A4H dry pumps feature sophisticated thermal management to prevent deposition, for long lifetime & low operating costs.

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