Dry Etching / DRIE Bosch

Using state-of-the-art equipment and the expert knowledge of DRIE of silicon using the BOSCH process and the DRIE of glass as well as the standard RIE (reactive ionic etching) of non conductors such as silicon oxides and silicon nitrides, Micronit GmbH fabricates your customised microfluidic or MEMS product individually.

Deep Reactive Ion Etching

DRIE is the abbreviation of "deep reactive ion etching".

DRIE etching stands for the removal of material, typically the transfer of a lithographically created mask pattern in a deep layer. This is the result of the bombardment of the material with ions, which removes part of the source material. In contrast to many chemicals used in wet etching, the dry etching process etches typically directionally or anisotropically. Here the addition of different gazes determines the angle and the side profile of the structure.

DRIE of Silicon

High aspect ratios can be realised using the DRIE process. The nearly vertical side walls are a process related advantage of the BOSCH process.

The silicon structures can be etched very deep using the BOSCH process. Thanks to the high aspect ratio the structures or devices can be packed in high density on the silicon wafer.

To achieve the high aspect ratios, the BOSCH process alternates in short seconds between the etch gas SF6 and the passivation gas C4F8. The etched vertical side wall is immediately passivated and protected in the following etching step. This sequence of etchings and passivation is repeated until the chosen etching depth has been reached or until the structure goes completely through the wafer.

Technical Details

Technical Details

  • Aspect ratio 1:50
  • High etch rates
  • High accuracy
  • Through wafer etching
  • Multiple depths
  • Stopping on silicon oxide or -nitride membranes
  • Sidewall inclination (profile) control
  • Aligned front and back side etching

Applications

Applications

  • MEMS (accelerometers, micro motors, etc.), MOEMS
  • Comb structures for acceleration sensors
  • Cavities for pressure sensors
  • Springs for vibration sensors
  • Holes for sieves of silicon, oxide or nitride
  • Masters for nanoimprint or PDMS casting
  • Microfluidic channels and ports
  • MOEMS (optical switches, mirrors, etc.)
  • Connections (through holes) of electrical through wafer interconnects and glass structures
  • BioMEMS devices like mambranes and needles

DRIE of Glass

The dry etching of glass (DRIE) is a special feature and offers an alternative to the dry etching of silicon. Not only the pure quartz glass can be dry etched using this technology, but also less costly glass such as BF33® or D263®. With this unique technique Micronit GmbH is able to create deep, high density and high aspect ratio structures in glass substrates.

The glass wafer of Borofloat (BF33®) can be bonded anodically to silicon. Hereby high complex and highly integrated technologies for multidisciplinary applications can be fabricated.

Technical Details

Technical Details

  • Depths up to 80 µm
  • Positive taper
  • Multiple depths on a single wafer
  • Control of the profile of side walls
  • High tolerance of micro channels and wave guides
  • Aligned front and back side etching

Applications

Applications

  • Bio-MEMS structures
  • Lenses
  • Microfluidic channels
  • Lab-on-a-Chip
  • Wave guides, MOMS
  • Special MEMS devices
  • Cavities for glass and packages

If you have any questions or requests, please call +49 (0) 231 88 68 077