Types of Thermal Interface Materials
Here are the 7 types of thermal interface materials:
Thermal interface materials (TIMs) are critical to maintaining the safety and functionality of heat-generating components within an electronic device. The thermal energy generated by the device components must be removed from the ambient environment, or else the device and its surroundings are at risk of failure. Key properties of thermal interface materials include high thermal impedance and conductivity. But since no two thermal interface materials are created equal, it’s essential to understand which materials are best for your application.
Still need help understanding thermal management? We break down the most common terms here.
Thermal Gap Fillers
Thermal gap filler gels are highly conformable, pre-cured, single-component compounds. The cross-linked gel structure provides superior long term thermal stability and reliable performance.
Gap fillers are malleable, making them ideal for applications where there are varying distances between the heat-generating device component and other sensitive materials. These interface materials are also well suited for applications with rough or uneven surfaces, ensuring that the malleable material fits into cracks and crevices to provide optimal thermal management and control. With precise pressure, gap fillers spread evenly across the surface of a device component to provide high thermal conductivity.
Ultimately, gap fillers give peace of mind to engineers who might otherwise be concerned about a device component’s proximity to heat-generating components or any hard-to-fill air gaps within the application itself.
Gap Filler Gels
Features
- Dispensable
- Fully cured
- Highly conformable at low pressures
- No refrigeration, mixing or filler settling issues in storage
- Single dispensable TIM can
- Eliminate multiple pad part
- Sizes/numbers
- Reworkable
Applications
- Automotive electronic control units (ECUs)
- Engine control
- Transmission control
- Braking/traction control
- Power conversion equipment
- Power supplies and uninterruptible power supplies
- Power semiconductors
- MOSFET arrays with common heat sinks
- Televisions and consumer electronics
Gap Filler Pads
Thermal gap-filler sheets and pads offer excellent thermal properties and highest conformability at low clamping forces.
Features
- Ultra-low deflection force
- High thermal conductivity
- High tack surface reduces contact resistance
Applications
- Telecommunications equipment
- Consumer electronics
- Automotive electronics (ECUs)
- LEDs, lighting
- Power conversion
- Power semiconductors
- Desktop computers, laptops, servers
- Handheld devices
- Memory modules
- Vibration dampening
Phase-Change Thermal Gap Filler Pads
Phase change thermal materials (PCM), as its title suggests, are capable of changing physical states – typically from solid to liquid, and vice versa. PCMs are particularly beneficial to reduce any existing thermal resistance between surfaces without losing that thermal energy completely.
As it changes from one state to another, phase change materials are able to retain and release thermal energy making it one of the most versatile materials used in thermally dynamic environments.
This unique characteristic allows for optimal energy storage efficiency, where energy can be stored within the material and utilized at a later date or in a different application. Thermal pads completely fill interfacial air gaps and voids.
Features
- Low thermal impedance
- Proven solution – years of production use in personal computer OEM applications
- Demonstrated reliability through thermal cycling and accelerated age testing
- Can be pre-applied to heat sinks
- Protective release liner prevents contamination of material prior to final component assembly
- Tabs available for easy removal of release liner (T710, T725*, T557, T777, PC07DM) * T725 is only offered with a tab
- Available in custom die-cut shapes, kiss-cut on rolls
Applications
- Microprocessors
- Graphics processors
- Chipsets
- Memory modules
- Power modules
- Power semiconductors
Features
- Offered in various forms to provide thermal, dielectric, and flame retardant properties
- Offered in custom die-cut configurations to suit a variety of applications
- Eliminates the need for mechanical attachment (i.e. screws, clips, rivets, fasteners)
- Proven reliability under various mechanical, thermal and environmental stresses
- Embossed version available
- UL recognized V-0 flammability
- No curing required, unlike epoxy or acrylic preforms or liquid systems
- Easily reworkable
Applications
- Mount heat sinks to components dissipating < ~25 W
- Attach heat sinks to PC (esp. graphics) processors
- Heat sink attachment to motor control processors
- Telecommunication infrastructure components
Cure-in-Place Potting and Underfill Materials
Cure-in-place potting and underfill materials are made of silicone elastomers. These thermal interface materials are dispensable form-in-place compounds designed for heat transfer without excessive compressive force in electronics cooling applications.
Features
- Cures in place once dispensed
- Dispensable form-in-place gap filling, potting, sealing and encapsulating
- Excellent blend of high thermal conductivity, flexibility and ease of use
- Conformable to irregular shapes without excessive force on components
- Ready-to-use cartridge system eliminates weighing, mixing and de-gassing steps
- Variety of kit sizes and configurations available to suit any application (handheld twin barrel cartridges, Semco® tubes and pneumatic applicators)
- Vibration damping
Applications
- Automotive electronic control units (ECUs)
- Engine control
- Transmission control
- Braking/traction control
- Power conversion equipment
- Power supplies and uninterruptible power supplies
- Power semiconductors
- MOSFET arrays with common heat sinks
- Televisions and consumer electronics
Thermally Conductive Electrical Insulator Pads
Features
- Excellent mechanical strength and puncture resistance
- Available with & without acrylic PSA
- UL recognized V-0 flammability rating
- Good thermal properties
- Good to excellent dielectric strength
- Available on continuous rolls for easy peel and stick application
BENEFITS
- Excellent thermal properties
- High dielectric strength
- 100% inspected for dielectric properties on every sheet
- Extremely low NASA outgassing
- Proven through decades of use in demanding military and aerospace applications
Applications
- Power conversion equipment
- Power supplies & UPS
- Power semiconductors
- Automotive electronics
- Motor and engine controllers
- Televisions and consumer electronics
Thin Heat Spreaders
Heat spreaders provide a low-cost, effective means of cooling IC devices in restricted spaces where conventional heat sinks are inappropriate.
Features
- Component junction temperature reduction of 10 to 20°C is common
- Easily added to existing designs to lower component temperatures and improve reliability
- Custom shapes available for complex designs
Applications
- Microprocessors
- Memory modules
- Laptop PCs and other high density, handheld portable electronics
- High speed disk drives
Thermal Greases
Thermal greases are just what they sound like – grease-like substances specifically designed for high thermal conductivity. This thermal interface solution is very common and accessible, making it perfect for homegrown applications or prototyping. The grease is meant to be used on flat surfaces due to its fluid state and should be used according to the desired level of resistance between surfaces.
These materials are screened, stenciled, or dispensed and require virtually no compressive force to conform. Slight pressure can be applied to ensure the grease saturates its intended surface, but in rough surfaces, the grease likely will not fill all gaps or holes.
An important consideration when using grease interface materials is that they aren’t particularly easy to clean up, as expected with most greases.
Features
- Silicone based materials conduct heat between a hot component and a heat sink or enclosure
- Fills interface variable tolerances in electronics assemblies and heat sink applications
- Dispensable, highly conformable materials require no cure cycle, mixing or refrigeration
- Thermally stable and require virtually no compressive force to deform under typical assembly pressures
- Supports high power applications requiring material with minimum bond line thickness and high conductivity
- Ideal for rework and field repair situations
Applications
- Mobile, desktop, server CPUs
- Engine and transmission control modules
- Memory modules
- Power conversion equipment
- Power supplies and UPS
- Power semiconductors
There are several suitable interface materials for any given project, but our tenured team at KRA Fabrication solves for the most efficient and lasting thermal management solutions across a variety of industries. Contact us today to get started.
For more detailed information on thermal interface materials, visit the Parker Chomerics Thermal Catalog.