Application Highlight: DOWSIL TC-5960 Reduces Risks of Thermal Runaway

By Embedded Computing Design Staff

October 16, 2024

Silicon manufacturing is ramping up faster all over the world, and with the growing desire for ever-more sophisticated (and power-thirsty) AI processing capability, that’s not likely to slow down any time soon.

Along with that growth comes the expansion of all the various supply-side industrial enablement products and solutions, and one of the most important families of product in that space is made up of those items that make the extremely sensitive chips operate more smoothly and reliably.

One key, but oft-overlooked, member of that group is the thermally conductive lubrication compound that must be designed to provide high thermal conductivity, and low pump-out and high-temperature stability, among other benefits.

Efficient thermal transfer is critical for the cooling of electronic modules, and good pump-out resistance is also important, especially in bare die application. Of course, in both operation and manufacture, chips are vulnerable to overheating so that temperature stability is especially mission critical.

Application Use Case

There are many thermal transfer methods used to cool electronic modules by moving heat away from the chips and out into the environment. Some of these are:

Convection: Here, heat is transferred from the surface of the device to a coolant. Convection can be natural, forced, or mixed.
Thermal Vias: These are holes drilled into thermal dissipation pads to channel heat away from components.
Air Cooling: This is the most common method for cooling electronic equipment, where heat is dissipated directly into the air, often via a heat sink.
Liquid Cooling: A cool liquid is circulated to transfer the heat to air in a heat exchanger. Often used for high intensity computing systems.
Embedded Heat Pipe (EHP) and Pulsating Heat Pipe (PHP): Advanced heat spreaders that can improve thermal conductance and reduce maximum chip temperatures.

All these strategies are designed to avoid the dreaded thermal runaway. This occurs when heat generation in an electronic device gets ahead of the cooling capacity and so temperatures keep rising until the device shuts down or it is destroyed or damaged. If you’ve ever had your legs burned by an old laptop, you’ll be familiar with the problem.

With the drive toward smaller and more compact device designs, more heat often is generated in devices. Moreover, thermal management of PCB system assemblies is a primary concern for design engineers. The cooler that a device can operate, the more efficiently and reliably it can operate over its lifetime.

Thermally conductive compound plays an important role in this cooling process by acting as a thermal “bridge” that removes heat from a device and transfers it away via a heat transfer media such as a heat sink. Such a compound should have low thermal resistance, high thermal conductivity, and thin Bond Line Thicknesses (BLTs) which can help to improve the transfer of heat away from the device. Thermal compound in particular can have advantages over other Thermal Interface Materials (TIMs) because it can prevent pump-out, is easier to apply to heat sinks via screen printing, and is simpler to re-work.

Let’s take a look at one of these solutions.

DOWSIL TC-5960

DOWSIL TC-5960 thermally conductive compound is a grease-like material that has been designed with a massive load of thermally conductive fillers in a silicone matrix. This design is intended to promote high thermal conductivity, low pump-out and high-temperature stability, the company said.

The compound is designed to maintain a positive heat sink seal to improve heat transfer from an electrical device or PCB system assembly to a heat sink or chassis especially for consumer devices. It provides efficient thermal transfer for the cooling of electronic modules, and is also rated for good pump-out resistance, especially in bare die application, Dow said.

The DOWSIL thermally conductive compound is a solvent-free formulation so the material remains stable after the container is opened, and so the viscosity of the material will not change over time. It can be applied in a variety of ways, including screen printing, stencil printing, and dispensing. Thanks to its stable viscosity, it’s easier to screen print consistently.

Other Features & Benefits:

Excellent pump-out resistance for bare die application
High thixotropy
One part material – no cure required
Solvent free formulation – provides material stability
Easy application – screen and stencil printable
High thermal conductivity
Low thermal resistance
Achieves thin Bond Line Thickness (BLT) Composition
Thermally conductive fillers
Siloxane polymer matrix

A heat sink or other thermal mitigation technique can often get the job done, but when the risk of thermal runaway can mean lost revenues, equipment, and time to the tune of thousands and millions of dollars, the added protection of a thermally conductive compound like DOWSIL TC-5960 can be a clear benefit.