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To: pgerassi who wrote (21393)	12/3/2000 1:53:47 PM
From: muzosi	Respond to of 275872

thanks Pete; saving this post. Muzo

To: pgerassi who wrote (21393)	12/3/2000 10:38:57 PM
From: Ali Chen	Read Replies (3) \| Respond to of 275872

Pete, <If the wafer is 1mm thick and the thermal conductivity of common silicon is .8W/cmC, The wafer will cause a thermal drop of (45.7W/sqcm)(.1cm)/(.8W/cmC) or 5.7C.> <Most good heatsinks are rated ... In this case, the drop is (55W)(.35 C/W) or 19.3C.> <This places almost all of the thermal resistance in the bulk die itself. Here a 40% increase in conductivity will drop the temperatures 30%> From what you wrote one can conclude that for the more or less realistic and manufacturable conditions, the die is responsible for 25% of the total resistance. Making the die even infinitely conductive would save you those 5.7C, or only 25% of total temperature difference. How did you arrive to 30% savings is beyond my comprehension ;) :) I reiterate my opinion on Insaneonic: this is BS. The 30% number is highly misleading, to say very softly. Reminds me the RMBS. Regards, - Ali

To: pgerassi who wrote (21393)	12/4/2000 1:04:41 AM
From: Mani1	Read Replies (1) \| Respond to of 275872

Pete, I am not going to nitpick your numbers, but even if I use your 5.7 degree delta T for the wafer, that would only be only 10% of the overall resistance. If ambient is 25 C and the maximum die temp (not junction) is 95 C, then 5.7/(95-25) is only 8%. Iosonic advertises a 40% reduction in thermal conductivity which leads to a 3% reduction of the overall resistance. I think the whole model is based on very localized hot spots, here is a quote from isonics.com Q. How does a thin layer of silicon-28 with higher thermal conductivity affect the temperature in a microprocessor when the heat must diffuse through the bulk silicon wafer, which is much thicker? A. The average temperature of the chip will probably not be affected.However, the very localized temperatures at the p/n junction of a transistor can be greatly affected. It says elsewhere This area comprises only 1-2% of the area of the silicon chip and localized temperatures can exceed 150oC I suppose if you make the hot spots localized enough, you could come up with their numbers. I think Iosonic is just a company desperate for funding and is trying to get some publicity. I doubt anything will come out of it for at least 5 years. Mani