Book Excerpt: Thermal Management With Insulated Metal Substrates, Part 3
July 1, 2020 | Didier Mauve and Ian Mayoh, VentecEstimated reading time: 2 minutes
The following is an excerpt from Chapter 3 of "The Printed Circuit Designer's Guide to... Thermal Management With Insulated Metal Substrates," written by Ventec International Group’s Didier Mauve and Ian Mayoh. In this free eBook, the authors provide PCB designers with the essential information required to understand the thermal, electrical, and mechanical characteristics of insulated metal substrate laminates.
Chapter 3: Developments in Insulated Metal Substrate Laminates
The insulated metal substrate concept is not new. Materials were available as long ago as the mid-1960s for specific niche-market applications. However, the exponential growth in LED lighting has been the main driver for the development of improved versions in volume manufacture. Insulated metal substrate laminates are now firmly established as the preferred base material for the fabrication of printed circuits for high-brightness LED lighting and DC power conversion applications because they offer cost-effective performance with straightforward fabrication, good mechanical stability, and a range of thermal conductivities to suit particular configurations.
Although thermal PCB design technology has been predominantly single-sided, multilayered constructions are now possible through resin-coated foil and resin-coated film options. The use of thermally conductive prepregs and copper clad thin laminates manufactured with them, which can be bonded to the insulated metal substrate or co-laminated with high Tg or low Dk and Df cores and prepregs, have also made multilayered constructions possible.
The recent progress made by these thermal prepregs and thin cores allow engineers to design multilayered PCBs with integrated thin thermal layers. This opens up many possibilities, particularly when convection is not an option due to space, or real estate, and the cost of additional radiators is a concern.
Dielectric Layer
The key element of an insulated metal substrate material is the thermally conductive dielectric layer between the copper foil and the aluminum plate. This may be a woven-glass reinforced-resin composite (prepreg), as in a conventional laminate construction, or a layer of unreinforced resin. The resin itself is typically a halogen-free epoxy-laminating resin. Whereas a conventional FR-4 laminate would have very poor thermal conductivity, the thermal conductivity of the resin component is significantly improved by loading it with up to 70% of a thermally-conductive ceramic filler. The resin must also continue to serve the fundamental purpose of reliably bonding the insulated metal substrate construction together under potentially severe thermal-cycling conditions.
The thermal conductivity of glass-reinforced materials is still limited by the nature of the glass, so it is the non-reinforced dielectrics that have the lowest thermal resistance. However, they demand critical control in manufacture to maintain consistency of dielectric thickness, whereas glass fabric provides a natural mechanical spacer.
To download this free eBook, published by I-Connect007, click here.
To view the entire I-Connect007 eBook library, click here.
Suggested Items
Trouble in Your Tank: Supporting IC Substrates and Advanced Packaging, Part 5
03/19/2024 | Michael Carano -- Column: Trouble in Your TankDirect metallization systems based on conductive graphite or carbon dispersion are quickly gaining acceptance worldwide. Indeed, the environmental and productivity gains one can achieve with these processes are outstanding. In today’s highly competitive and litigious environment, direct metallization reduces costs associated with compliance, waste treatment, and legal issues related to chemical exposure. What makes these processes leaders in the direct metallization space?
AT&S Shines with Purest Copper on World Recycling Day
03/18/2024 | AT&SThe Styrian microelectronics specialist AT&S is taking World Recycling Day as an opportunity to review the progress that has been made in recent months at its sites around the world in terms of the efficient use of resources:
Matrix to Exhibit at IPC APEX EXPO 2024 in Anaheim, CA
03/05/2024 | MatrixMatrix will be exhibiting at IPC APEX EXPO 2024, to be held on April 9-12, 2024, at the Anaheim Convention Center, Anaheim, CA.
The Chemical Connection: Getting to Know Your Vendor
02/16/2024 | Don Ball -- Column: The Chemical ConnectionAfter working for a capital equipment supplier for almost 50 years, I’ve found that the most important part of getting to know your vendor is good communication among all parties. While contact between fabricators of a constantly changing product line and the designers of those products may occur daily or weekly, conversations between you and your equipment supplier may be years apart. That lengthy gap often means that previous contacts may have been promoted, retired, or moved on to other opportunities. You may have also migrated to a new supplier with whom you have little or no history. In either case, you will be interacting with someone you are unfamiliar with (as they are with you). Therefore, it is essential for both sides to communicate clearly so expectations will align.
EIPC Winter Conference 2024, Day 2: A Closer Look at Global Trends
02/14/2024 | Pete Starkey, I-Connect007The opening session of the second day’s conference proceedings focused on global PCB trends and was introduced and moderated by Dr. Michele Stampanoni, vice president of strategic sales and business development at Cicor Group in Switzerland. He opened the session with Dr. Hayao Nakahara’s knowledgeable and enlightening video presentation on the IC substrates industry.