Products and Services
Products and Services > Submount
Products and Services > Submount

Fionix provides silicon, ceramic, and glass submounts for optical components, RF devices, MEMS components, and sensors. Aluminum nitride (AlN) and aluminum oxide (alumina, Al2O3) are the most widely used ceramic materials for submount applications due to its excellent low-loss dielectric properties from DC to GHz frequencies. AlN has higher thermal conductivity than alumina so preferred to heat generating devices. Normal medium resistivity silicon wafers have very high dielectric loss compared to AlN and Alumina, but high resistivity silicon (HRS) can provide low dielectric losses comparable order to ceramic substrates. Silicon substrates have many advantages such as mature technology platform, low substrate pricing up to 8 inch, mechanical robustness, and easy post processing such as thinning, lappping/polishing, and dicing. Glass substrates also can be used for submounts requiring low dielectric loss and low parasitic capacitance. Advantage of glass substrate is its transparency enabling inspection from bottom surface. Fionix also provides carrier and cap wafers for wafer bonding and/or diced individual component sealing.

Substrate materials:    
- Silicon    
- Alumina(Al2O3) and aluminum nitride(AlN)    
- Quartz and Fused silica

- Wire bonding pads    
- Solder bumps ; Au-Sn, UBM, solder dam    
- Passivation ; silicon oxide, silicon nitride, polymer    
- Transmission lines ; CPW

- Submounts for laser diodes and photodiodes    
- Optical subassembly, TOSA, ROSA    
- RF, MEMS, Sensor

Capping wafer for hermetic metal sealing of active devices with through cap vias