Silver plating on top of a computer processor

[jungle]

ok this is a pretty novel idea that im sure no one has done before. well if you have then it would be great if you could tell me how it went. anyway a little background on the project.

computer cooling is essential when trying to overclock (run the computer faster than stock speed) and can be an interesting hobby. years ago, supercomputers were cooled by water. more recently, the average joe has started using water to cool the processor, northbridge, southbridge, hard drive, video card, or any combination of these. the conventional way to water cool is to make a copper waterblock, mount it on top of the processor and run water through it. silver is a better conductor of heat then copper, but the amount one would need is nearly cost prohibitive. another idea was running water directly over the top of the processor, but the cpu die, the part that generates heat, soaks up water over time and shorts out. lately people have been trying to make the baseplate of copper waterblocks thinner so that there will be less thermal resistance. hope you are still with me.

my idea is to silver plate (remember silver is better than copper at conducting heat) the die of a processor. the die has a non-conductive coating that would have to be sprayed with silvaspray. so i have some questions for the more experienced and knowledgable.

I am looking to get the thinnest layer of silver possible, any tips?
also, the top of the die appears to be perfectly smooth. if i spray it with silvaspray and am not worried about appearance of the finish, would it be necessary to do all the buffing and cleaning that is "99% of the process?" i worry that very much of that would damage the processor. im already dunking it in acid as it is lol.

final question, there is a sealant that is used to seal porous substrates. now how porous are we talking here? the top of a processor has no visible pits. however, it does apparently soak up water. do i need to seal it, or is porous more of a sponge-like reference?

thanks for the help. jungle

[dadkar2]

semicoductor plating?

I personally wouldn't mess with highly acidic or basic chemicals anywhere near a processor chip. When these diffuse their way to the silicon device substrate they will undoubtedly destroy the silicon lifetime or gate oxide purity and your device will be finished. Heat will accelerate the diffusion. Stick with copper and buy some of today's extremely good thermal glues designed for this application. They are great gap fillers anyhow which will go much further towards enhancing the thermal conductivity than the silver. The Silvaspray is probably a poor thermal conductor anyhow since it is silver particles suspended in paint, which is a poor thermal conductor.

Ken

[jungle]

i knew people would advise me not to try it. but a friend of mine already has, and we're working together on it. he tried it with a dead processor and plated over a metal heatspreader, but the difference wouldnt be that great. i realize that silvaspray would be a poor conductor of heat, and that is pretty much the only thing that would make it not work. however, the coating of paint will be minimal. the description said that you could coat it as thin as 16 microns or so. with that thin of a layer, i doubt that the insulation properties will come into play much. as for the thermal paste, its conductivity is nothing compared to silver. it does, however, have a much better conductivity than non-moving air. consequently, its purpose is to fill gaps between the heatsink and die to replace the air. but anyone who knows about cooling will tell you to use as little paste as possible to make the connection because temps will rise as amount of paste increases. i would be covering the parts that i don't want to plate with beeswax, which is recommended to prevent plating and acid contact. besides that masked part, the actual plating area should be in contact for only a short time because the silver will begin to deposit on its surface. plus, it has the layer of silvaspray to sheild it. i dont believe the acid will be a problem.

[fractal]

The question has been raised on several overclocking forums and the general concensus is that it won't help much. But, if you really want to try .. I would make sure I lapped both the heat sink and the processor. The process of lapping is well documented on all the overclocking sites. It looks to me like the plug'n'plate product would be ideal for depositing a thin layer of silver on the heat spreader without having to dunk the entire processor in plating solution. My guess would be that the heat spreader is grounded so you could jury rig a socket with a wire connected to the ground pin(s) to connect the aligator clip. Otherwise just have your friend hold the clip in contact with one part of the spreader while you plate another part.
You might also want to plate the heat sink to avoid any issues with dissimilar materials.

One of my projects has been to either silver plate or gold plate my heat sinks. Not so much because I think they will dissipate the heat better as much as I think it would look cool.

[dadkar2]

Silver plated micro

I agree...it doesn't seem likely to help much if at all. The likely benefit vs. the risk seems too out of balance to be worth trying. But, fractal's point is well taken. Lapping is key.

My understanding is you're working on the backside silicon of the processor device. I may be mistaken in my understanding. But if you are, I wouldn't allow any ionic material (like plating solution!) in contact with it. Heavy metals diffused into silicon will destroy a device! Painting it with silvaspray will more than likely result in an uneven surface, and remember--paint is an insulator, even with conductive particles suspended in it.

Remember that no matter how well you lap the surfaces, a gap filler would still be advised. It would also be helpful to polish both surfaces to as high a shine as possible, as long as this step does not destroy the overall flatness of the surface.

Ken

[jungle]

the main point you are missing is this: there is a big difference between what im trying to do and plating a heatspreader. the heat spreader (not present on amd cpus in the first place) would be removed if it were there or if the plating were attempted on a p4. take this pic as a reference.



the black rectangle in the center is the die, the target of plating. The area around it is the substrate (same term as in plating but not the same thing) of the processor. i am attempting to spray the top with as even and thin a coating of silvaspray as possible, then plate as thin a layer of silver as possible on top of that. the reason, theoretically, that this would do better than using a heatsink atop the normal ihs (integrated heatsink), assuming that it is present in the first place, is the mounting method. the heatsink is interfaced to the die using a type of thermal glue. this glue, however, does not have anywhere near the heat conductivity of silver, copper, or pretty much any metal for that matter. this is the reason that it is used in such small quantities, to fill the gaps sufficiently to eliminate the air bubbles (the glue is much better at conducting heat than the air), but at the same time have the thinnest layer of the glue possible to decrease the thermal resistance before the minimal resistance of the heatsink.

keep in mind I AM NOT USING A HEATSINK. the thin layer of silver will act as a heatsink, and water as the coolant. THERE WILL BE NO THERMAL PASTE because there is no need for it. since i am not joining anything but the plated silver layer and the processor, the need for thermal paste is nullified, which will improve temps. Thermal paste is used, as mentioned, to eliminate gaps filled with non-moving air between the heatsink and the source of the heat, the die. By using a very thin layer of silver that is electroplated directly onto the die itself, aside from the thinnest possible layer of silvaspray, the gap problem is eliminated, thereby eliminating the need for the paste AND the extra thermal resistance.