Ceramic substrates such as alumina, aluminum nitride, and beryllium oxide are highly thermally conductive materials which transfer heat away from hot spots quickly and efficiently, dissipating it over the whole surface. PCB material (FR-4) is epoxy based with poor thermal conductivity, leading to hot spots which reduce the life of most semiconductor junctions. Typical thermal conductivities of ceramics and FR-4 are:
Hybrids are microelectronic circuits comprising multiple devices, often in die form, within a hermetically sealed metal enclosure or an impervious conformal coating. All components are insulated and isolated to a high level, giving constituent parts protection from moisture ingress. Hybrid substrates have their conductive tracking and insulating layers fired at 850°C for a peak period of 10 mins., with conductive adhesive device terminations being cured at 150°C for two hours. By comparison, FR-4 PCB assemblies face a maximum temperature of approximately 80–260°C for short periods, beyond which damage to the PCB structure starts to occur.
Higher Temperature Operation
Hybrids utilize components which are capable of long term operation up to 250°C. MPT is building on its experience with hybrid technology in designing and fabricating hybrids for high-temperature operation.
Active Resistor Trimming
Resistor values can be adjusted by laser trimming during the functional operation of the circuit, allowing the dynamic tuning of circuits as an automated production process.
Maintain Electrical Characteristics in Conversion
Single-board computer assembly on MPT ceramic engineered substrate (left) and FR-4 (right). All electrical characteristics and specifications are maintained.