Dave Sommervold, Chris Parker, Steve Taylor, Garry Wexler
The Bergquist Company
Prescott, WI USA
The ever expanding growth in the use of insulated metal substrates (IMS) in power electronics requires a focus on material and mechanical configuration for each application. By optimizing the material makeup and printed board format, performance and reliability expectations can be further achieved. The thermal performance and electrical isolation needs are driven by the power requirements, but considerations of temperature range, mechanical durability and format, along with the physical package surrounding the substrate must also be managed.
With a variety of material configurations and circuit format capabilities, the choices become a balancing of options to maximize performance and minimizing cost through Design For Manufacturability (DFM) in the circuit board fabrication. These challenges present the IMS printed board fabricator with material selections and fabrication processes unlike those for other printed board or ceramic applications.
IMS substrates provide many advantages in power electronics and LED designs with the variety of material selections and circuit fabrication possibilities, examples shown in figure 5. The design does need to narrow down the choices of material configurations to meet performance and price requirements. Matching thermal performance, safety agency testing needs and best fabrication method can be greatly enhanced with a strong technical relationship with the material/fabricator vendor.
With the continued increases in power density and the exploding LED lightning market, more and more designers will have to look to IMS substrates for their applications needs. However the amount of differentiation from traditional FR-4 fabrication forces the need apply design practices not previously considered.