Thermal Interface Material (TIM)

Thermal Interface Material TIM

Combine a range of ASYMTEK products to create batch or large-volume TIM dispensing solutions for semiconductor packaging, PCBA, and precision assembly dispense applications.

Overview

Heat presents a significant challenge for electronics packaging and can, in part, limit further miniaturization. 

Thermal interface material (TIM) improves heat transfer between two surfaces to manage that limitation. This article discusses the types of TIMs, their use, and the benefits of dispensable TIM. 

Where is TIM Used?

TIM 1 is dispensed between a flip-chip integrated circuit (IC) and a heat-spreading lid. TIM 2 is dispensed between a finished package, component, or module and a heat spreader in the form of a case, metal housing, or heatsink. And TIM 1.5 refers to materials dispensed between an IC without a lid and a heatsink.

TIM 1, TIM 2, and TIM 1.5 examples:
TIM Types.jpg

Dispensable TIM Materials

Thermal Grease
Thermal greases are silicone-based materials containing thermally conductive fillers. They do not require curing, are reworkable, and conform well to surfaces, offering excellent thermal performance and heat dissipation for high-watt devices.

Thermal Adhesive
Thermal adhesives are available in one or two-component fluid formulations with performance similar to thermal grease but with the added benefit of adhesion. They are easy to dispense, reworkable, and provide structural support.

Thermal Gap Filler (Gel, Paste, Compound)
Thermal gap filler is also available in one or two-component fluid formulations. This paste-like material offers performance similar to thermal grease, without the risk of material pump out, and is suitable for achieving greater bond line thicknesses (BLT). Two-component thermal gap filler is ideal for low-stress applications. This material is reworkable, with the two-component formulation offering less workability. 

Thermal gap fillers are highly viscous, abrasive, stringy, and challenging to dispense. If you’re setting up a large-volume thermal gap filler dispensing application, we can help you identify the right equipment and the ideal application approach to address these challenges. 

Liquid Metal
Liquid metal offers high electrical conductivity. This TIM has been available for a long time, with interest in its use rising in recent years. It is less sensitive to BLT but can be complex to dispense.

Solder
Although it's not commonly thought of as a TIM, solder is used, for example, in high-powered LED die-attach applications.


Non-Dispensable TIM Materials

Phase Change Material
When heated up, phase change materials transition from a solid to a semi-solid state. These wax-like materials conform well to surfaces, do not require curing, and are commonly applied through a printing process. The sticky nature of these materials makes them challenging to rework. 

Thermal Tape
Thermal tapes are filled with pressure-sensitive adhesive (PSA). These tapes are primarily used for adhesive properties when thermal performance is secondary. Thermal tape requires consistently flat surfaces and is difficult to rework.

Thermal Pads
Pre-formed silicone pads with conductive fillers are applied to fill gaps between packages, components, and modules. The pads are reworkable and sensitive to applied pressure, improving performance when higher pressure is applied. 

Dispensable TIM vs. Thermal Pads

Compared to solid, stamped thermal pads for dissipating heat, thermally conductive fluids are ideal for filling gaps of various sizes, forming complex dispense patterns, and achieving thinner bond lines. Thin bond lines reduce the distance heat must travel to escape the heat source, minimizing thermal resistance. In general, dispensable thermal interface materials:

  • Offer higher thermal conductivity when compared to solid thermal pad materials.
  • Conform well to substrates, filling the tiniest air gaps to improve heat transfer.
  • Reduce the risk of defects by minimizing assembly stress on sensitive electrical components.
  • Reduce or eliminate storage and manual assembly costs.


Recommended Products