Below are the questions asked during the presentation, along with their respective answers.
Q: With regards to keeping the thickness of the interface to a minimum, is there any benefit in using a 2-part compound versus a thermal pad?
A: The benefit of using a 2-part compound such as PS-1931 is that bondlines are minimized and whet-out is nearly perfect due to the liquid nature of the product at time of use. The 2-part product will flow onto the surface, filling in surface imperfections which reduces thermal resistance, and can be compressed with very little pressure during assembly. The minimum bond line for a 2-part thermal compound is ~50um which is 5 times thinner than the thinnest thermal pad. In other words a 50um 2 part compound will create only 20% of the temperature rise of a 0.25mm thermal pad of the same conductivity.
Q: When will increasing the conductivity of my thermal interface add no more benefit in terms of keeping my component cool?
A: We saw that a 5W heat source would create a 8C temperature rise across a 1W/mK thermal pad and that we could reduce that temperature rise to 2C by using a 4W/mK thermal pad instead. We could further double the conductivity to 8W/mK and reduce the temperature rise by another 1C and double the conductivity again and reduce the temperature rise by another 0.5C. The bottom line is the returns are diminishing as the temperature gets closer to zero and will actually never reach zero. So the question is how much is too much?
Q: Should we account for pump out and volatility of the TIM material in design?
A:Oil bleed and outgassing will occur – but in very small amounts only. Our thermal interface materials have very low outgassing (<0.1% VOC at 120C), so change in volume should be negligible.
Q: How de we calculate R surface?
A: The R surface is measured using a hot plate / cold plate setup where the power going across the interface is known and the temperatures (hot and cold) are also known. The thermal resistance of the interface is plotted as a straight line against the thickness and the thickness t=0 is the R surface.
Q: What are some key applications that may experience growing demands for thermal management solutions in the near future?
A: The emergence of battery-powered vehicles is driving large demand for thermal interface materials. Aside from EV battery applications, other automotive areas such as infotainment, lighting and connectivity options within the various modules of the vehicle will require some type of thermal management. In addition to automotive, the market for consumer electronic and lighting will continue to grow demand for these materials in the coming years.
Q: Are any of the TIMs outgas at operational temperatures? I am concerned about optical products.
A: Our TIMs are measured for outgassing at 120C. At this temperature, we expect <0.1% total weight loss due to outgassing.
Q: How the wettability can affect the TIM performance?
A: Better whetting will produce a more intimate contact of the surfaces, mitigating the formation of bubbles or other forms of resistance at the interface. This whet-out will provide a more efficient thermal path, hence lowering the temperature rise across the interface.
Q: How do you test these materials for reliability?
A: Reliability is tested by simulating point of use testing. This simulation in the laboratory setting will submit the product to worse-case conditions and measure performance of the material across multiple lots and statistically analyze the data to determine if any change which could lead to a module failure is likely to occur.
Q: What type of filllers re used for PS-1545?
A: Alumina particles are being used.