Dry Etch

RIE of

• Oxides
• Metals
• Silicon

RIE of Membranes

• TiAl

DRIE of silicon

• Aspect ratio up to 40
• Side wall angle 90° ± 1°

Silicon deep etching (Bosch process) is one of the core competencies in our clean room at Fraunhofer IPMS. This highly precise and repeatable etching process enables the fabrication of deep, anisotropic structures in silicon substrates, which are essential for a variety of applications in micro- and nanotechnology.

Our state-of-the-art equipment and experienced team ensure that the most complex designs are realized with the highest accuracy and consistency.

Process

• Metal etch (Al / Al alloys)
• Dielectrics & poly etch (SiO2, Si3N4,
• PolySi, a-Si)
• Deep silicon etch (aspect ratio up to 30)

Etching mechanisms

• 4 steps: generation, adsorption, reaction, desorption
• Etching rate, selectivity, anisotropy
• Reactions:
  • Plasma: CF₄ + e^- → CF3+ + F* + 2e^-
  • Si surface: Si + 4F → SiF₄
  • SiO₂ surface: SiO₂ + 4F → SiF4 + O₂

Equipment

Tokyo Electron and Applied Materials Mainframes for 12” Wafer (BEOL and FEOL)

• ICP and CCP reactors with RF pulsing options
• Gas pulsing and ALE processing
• High temperature etching (up to 250 °C)
• Highly flexible process gas selection
• Optional 8“ wafer processing
• In-situ plasma analytics (QMS, SEERS, HROES)