Etching

DRIE etching

Deep Reactive Ion Etching (DRIE or plasma etching) is a unique technique to create deep, high density and high aspect ratio structures in glass (fused silica) and silicon substrates. Micronit is one of the few companies able to use the DRIE method in glass substrates.

Etching with steep side walls (anisotropic etching) as well as with rounded walls (isotropic etching) in substrates is possible, with depths varying between 1 µm cavities and complete wafer-through holes.

Capabilities of Micronit in DRIE etching are as follows (based on a silicon substrate):

Aspect ratio 1:15;
Wafer-through etching;
Variable inclination of the channel walls;
DRIE on SOI wafers

Wet etching

Micronit applies wet etching (HF etching) techniques to create channel structures in glass and silicon. HF is a hydrofluoric acid, commonly used for cleaning metal and etching glass. For the HF etching technique we use masks which make the absolute positioning of the structures accurate within one micrometer. By using a mask, the amount of channels, reservoirs, mixing and reaction chambers is irrelevant for the costs of the process.

Abrasive Jet Machining (powder blasting)

Abrasive Jet Machining (AJM) or powder blasting, is a technique in which a particle jet is directed towards a target for mechanical material removal. Powder blasting is a flexible, cost-effective and accurate technique to create fluidic channels and interconnections. With an accuracy of within 2 µm and a feature size accuracy of around 25µm. The exact layout of the holes and channels can be very flexible.

Shaped wells can be round, rectangular or triangular. The sides of the wells will not be completely vertical, but sloped at an angle of 70 degrees (tolerance depending on specifications). Furthermore, the average roughness of the channels will be between 0.8 and 2.5 µm, also depending on the chosen process.

After the powder blasting process, the substrate can be bonded to another glass or silicon substrate. As the surface of the powder blasted substrate remains undamaged.

Abrasive-jet-machining-holes-channels.jpg Powder-blasting-holes-channels.jpg