Thermal FR4 by Aismalibar, the evolution of standard FR4

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Thermal FR4 by Aismalibar is a revolutionary FR4 enriched with mineral filler, capable of dissipating the heat more efficiently that a standard FR4.

Technology is the undisputed star of our everyday life. It represents the main resource of almost every aspect of our daily routine up to the great development potential for renewable energies.

Thermal management is, therefore, extremely important to ensure the best performance and efficiency of the electronic components.

Aismalibar Insulated Metal Substrates (IMS) offer the best solutions to reduce the operational temperature of Printed Circuit Boards and their components, ensuring both quality and reliability.

Table of Contents

Thermal management, why it is important

Since technology plays an important role in every aspect of our lives, thermal management becomes key point of integrated electronic components in order to achieve higher performance and efficiency.

Electronic conductors dissipate energy in the form of heat. Also, the energy is proportional to the intensity of the current electricity that passes through the conductor.

Physicist James Prescott Joule discovered this effect back in 1840. Since then it represents the basis for the operation of many devices.

This effect has, however, significant negative implications:

  • The dissipated energy reduces the efficiency of the electronic machine (except when the generated heat is the main purpose of its operation)
  • The heat, be it wanted or not, may be the cause of malfunctions or total breakages of the very apparatus that generates it.

As consequence, it is crucial to keep the temperature rise under control in order to reduce (if not eliminate) its negative effects.

Therefore, it represents every engineer's study's objective when designing an electronic machine, be it very simple (fuse) or complex (microprocessor).

Printed circuit board, the role of the standard FR4

First of all, when it comes to Printed Circuit Board (PCB) construction, FR4 is the most used material.

The reason behind this tendency is that boards made of FR4 are strong, water resistant and provide a good insulation between copper layers that minimizes interference and supports good signal integrity.

Standard FR4 thermal conductivity

As mentioned before, FR4 represents a base for electronic components.

Its thermal conductivity, however is very low, and designers need to take different approaches in order to dissipate the heat.

For this reason, the typical approaches PCB designers use to try to resolve heat dissipation are:


  • Heat sinks
  • Fans
  • Thermal pipes etc
  • Components immersed in liquid


  • Thermal vias
  • Copper Inlay
  • Heavy copper

Beside these solutions designers are starting to look at the
PCB substrate itself

On this path, Aismalibar presents its solution: Thermal FR4.

Aismalibar IMS solution to thermal management: Thermal FR4

In order to meet the ever increasing need to dissipate heat in nowadays electronic components, Aismalibar presents Thermal FR4.

Aismalibar R&D is constantly encouraged to find innovative and efficient ways to face the challenges of thermal management.

Thus, their great commitment, together with the most updated technology of Aismalibar labs, made possible the creation of Thermal FR4. A revolutionary FR4 capable of dissipating heat more efficiently than a standard FR4.

The anatomy of Aismalibar Thermal FR4

The higher thermal conductivity of the Thermal FR4 is given by adding minerals filler to the bond sheet.
While a standard FR4 has a thermal conductivity of max 0.3 W/mk, Thermal FR4 reaches a thermal conductivity of 2.2 and 3.2 W/mk (depending on the product).

Thermal conductivity

standard FR4 thermal conductivity

max 0.3 W/mK

Standard FR4

thermal FR4 thermal conductivity

2.2 and 3.2 W/mk

Thermal FR4

Component temperature Thermal FR4

Thermal FR4 Applications

Certainly, Thermal FR4 has several applications, the most typical of them are:

· Power modulus

· Automotive powertrain

· High Power LED

· AC-DC Power converters


Moreover, Thermal FR4 finds application in the construction of Metal PCB, copper or aluminium base.

Then, another interesting application of the Thermal FR4 is to be used for full construction of multilayers or combined with traditional FR4.

This combination is excellent to reduce the thermal stress on the layers.

Benefits of Thermal FR4

Also, Thermal FR4 presents benefits both in terms of cost and efficiency.

This is because FR4 PCBs with high density of thermal vias are replaceable with standard double side PCBs constructed with Thermal FR4.

Besides, Thermal FR4 counts with:

  • Excellent performance with laser drilling
  • Anti CAF
  • Low moisture absorption
  • Reflow test: over 60 seconds at 288 ºC
  • Standard press cycle lamination
  • HDI Technology compatible


To sum up we resume the main benefits of the Thermal FR4.

Firstly, Thermal FR4 achieves a better thermal release reducing the high cost of FR4 with thermal vias.

Secondly, being Thermal FR4 very versatile it can be delivered in single or double side configurations with different dielectric and copper thicknesses.

Finally, thanks to the Thermal FR4 it is now possible to reduce the board temperature and get a better performance and longer life on the electronic design.