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I was looking for IC packages where I can mount a small wafer (3mmx3mm) wire bond to the leads of the package and conduct operation at 500C. I have contacted couple of companies which do ceramic IC packages but they only guarantee operation till 250C. Would these ceramic packages hold till 500C? Also, is there any conductive thermal paste to mount the wafer which can sustain 500C? Any help would be very useful!

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    \$\begingroup\$ What kind of semiconductor are you using that can survive such temperatures? \$\endgroup\$ – pericynthion Sep 19 at 22:12
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    \$\begingroup\$ Do you actually have a wafer that can function at 500C? \$\endgroup\$ – DKNguyen Sep 19 at 22:14
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    \$\begingroup\$ I am researching in diamond \$\endgroup\$ – Harshad Surdi Sep 19 at 23:05
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    \$\begingroup\$ @HarshadSurdi I don't think diamond is on the market yet. I've seen some research about it but I don't think you'll find anyone with diamond ICs. There are diamond compounds for thermal pasting for heat syncing. Gallium nitride might also be something you should check out. \$\endgroup\$ – KingDuken Sep 19 at 23:24
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    \$\begingroup\$ You have some thoughtful comments and answers. I worked on something we designed to operate using standard commercially available parts, running them at 180 C (above their specs.) The useful running time we promised was on the order of hours, not weeks or months. So one big question I have for you is, "What duration of operation do you need?" The lack of any discussion of this seems to be a glaring hole in your question to me. \$\endgroup\$ – jonk Sep 20 at 6:37
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An IC usually consists of these things:

  • Epoxy to encapsulate the IC
  • Pins
  • Wire bonding (usually gold)
  • Chip or Die
  • Solder

I would think that the concern would be with each of the materials of the package. I know that most solders start to lose their structural stability at 250C. I know that IC epoxies don't survive much after 250C either from personal experience. The wire bonds would also need to support high temperatures. All of these components need to support operation higher than 250C.

I would think that the solder would be the most limiting factor, and solders with higher melting points can be found up to 450C, after that its a different process called hard soldering or brazing.

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    \$\begingroup\$ You forgot to add the important issue of heat expansion. If the coefficient of expansion is not matched it doesn't really matter if the materials survive the temperature change (e.g., don't melt) these can still crack, deform, or detach due to a mismatch on their expansion rates. \$\endgroup\$ – Edgar Brown Sep 19 at 22:46
  • \$\begingroup\$ Any idea what company sells these high melting point solders? \$\endgroup\$ – Harshad Surdi Sep 19 at 23:08
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Semiconductors become conductors above a temperature related to the band-gap. A few materials, such as pure carbon (e.g., diamond) and silicon carbide (SiC), have been used to make experimental or custom designed devices such as low power IC's and high power IC's that operate at 500°C.

As far as thermal transmission and insulation, diamond is ne plusa ultra. Since gallium wets diamond, you could make a Ga/C/Ga sandwich to conduct heat and insulate electrically. The diamond probably would be less expensive than the special-purpose IC!

Though you might be able to order (and afford!) such a device, might it be possible to move signal processing to a cooler location? Admittedly, in borehole logging and spacecraft to land on Venus, this might not be a choice, but look for a more practical alternative.

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