The MultiMEMS MPW Process

The MultiMEMS MPW Process is chosen to be a flexible manufacturing process useful for prototyping or small volume production. It is based on Infineon Technologies SensoNor’s key and well-established technologies of:

Precise control of membrane and/or mass thickness by use of electrochemical etch-stop technique;
Epitaxial layer for monocrystalline thin membranes and beams;
Release etching of masses and moving structures by reactive ion etching (RIE);
Patented sealed and/or vented cavities^[1] by means of:
- Glass micromachining and
- Triple-stack glass-silicon-glass wafer bonding;
Patented buried conductor crossings of bonded areas^[1];
Piezoresistive detection by means of:
- Long-term stable buried piezoresistors and/or
- Sensitive surface piezoresistors;
Thermal excitation and thermo-pneumatic actuation.

In one single device, it is possible to realise membranes with two different thickness values. The thinner membranes can be perforated by a dry etching step, thus enabling the production of beams, cantilevers, flexures or other moving structures, possibly in combination with mass elements or other rigid parts.

The wealth of possibilities offered by the MultiMEMS MPW process is illustrated in the cross-sectional view below. Typical examples are shown throughout the Applications pages.

Cross-Sectional View:

MultiMEMS die [Hide] [Show]

The process includes triple-stack anodic bonding of silicon with top and bottom glass wafers, thereby offering the possibility of protecting the structures in a hermetic seal. Both the top and bottom glass wafers are offered with cavities and/or with through-holes.

References

1. "Sealed Cavity Arrangement", U.S. Patent 5,591,679 (1997), European Patent EP 0742581 B1 (2002).