WHAT ARE THERMAL INTERFACE MATERIALS?

1.   Heat conduction interface material is a kind of material widely used in IC packaging and electronic heat dissipation. It is mainly used to fill the micro gap and uneven surface when the two materials contact, reduce the thermal resistance and improve the heat dissipation performance of the device.

Heat conducting interface material is a kind of polymer composite material with polymer as matrix and heat conducting powder as filler. It has good thermal and mechanical properties, and is widely used between the heat sink and the radiator in electronic components. It helps to form a good heat conduction channel to reduce the thermal resistance of heat dissipation. It is currently recognized as a good thermal solution in the industry.

2. The function of heat conduction interface material:

With the rapid development of modern electronic technology, the integration degree and assembly density of electronic components continue to improve, which not only provides a powerful use function, but also leads to the sharp increase of its working power consumption and heat generation. High temperature will have harmful effects on the stability, reliability and life of electronic components. For example, too high temperature will endanger the nodes of semiconductor, damage the interface of circuit, increase the resistance of conductor and cause mechanical stress damage. Therefore, to ensure that the heat generated by the heating electronic components can be discharged in time has become an important aspect of microelectronic product system assembly. For portable electronic products with high integration and assembly density (such as notebook computers), heat dissipation has even become the technical bottleneck of the whole product. In the field of microelectronics, a new discipline, thermal management, has been developed, which specializes in the safe heat dissipation mode, heat dissipation equipment and materials used for various electronic equipment.

Heat conducting interface materials play a very important role in thermal management, which is an important research branch of this subject.

The principle is as follows: there is a very small uneven gap between the surface of Microelectronic Materials and the radiator. If they are installed together directly, the actual contact area between them is only 10% of the area of the radiator base, and the rest are air gaps. Because the air thermal conductivity is only 0.025w / (m.k), which is a bad conductor of heat, the contact thermal resistance between the electronic components and the radiator is very large, which seriously hinders the heat conduction, resulting in the low efficiency of the radiator. Filling these gaps with thermal interface materials with high thermal conductivity, removing the air in them, and establishing an effective heat conduction channel between the electronic components and the radiator can greatly reduce the contact thermal resistance, make the radiator fully play its role, and ensure that the electronic components can work in the appropriate temperature range, and ensure the normal performance of the electronic components.

3. Introduction to common heat conduction interface materials:

With the increasing demand of microelectronics products for safe heat dissipation, heat conduction interface materials are also developing.

4. Characteristic index of heat conduction interface material:

Thermal conductivity: under the condition of stable heat transfer, two parallel planes with a distance of 1 meter and an area of 1 square meter are set inside the object perpendicular to the direction of heat conduction, and the temperature difference between these two planes is 1 degree. The heat transferred from one plane to another in one second is the thermal conductivity of the material. Its unit: W/MK.

5.  Main test equipment of heat conduction interface material:

1) The equipment used for testing is mainly thermal resistance measuring instrument and thermal conductivity measuring instrument.

2) Thermal conductivity: a physical quantity describing the thermal conductivity of a material. It is the inherent property of a single material, independent of the size and shape of the material.

3) Thermal resistance: a comprehensive parameter reflecting the ability to prevent heat transfer. In the engineering application of heat transfer, in order to meet the requirements of production process, sometimes the heat transfer is enhanced by reducing the heat resistance, and sometimes the heat transfer is inhibited by increasing the heat resistance.

6.  Application examples of heat conduction interface materials:

1) Chips (CPUs, GPUs, chipsets, etc.);

2) Electric pen and network server;

3) Mobile communication (base station, switch, etc.);

4) High power LED cooling charging post;

5) Power components without special insulation requirements;

6) conduction between semiconductor and radiator;

7) LCD and plasma TV;

8) Heat conduction of communication products;

9) On board communication electronic equipment;

 10) Set top box, handheld electronic device (micro projector).