Someone was recently selling an early MOS 6502 CPU on Ebay (date code 0277) in a ceramic package that had a couple of holes in it. You can see them clearly (under the tape, which presumably was not applied by MOS) in this image:

MOS 6502 package with holes

Another chip I've seen with the same holes is the early '70s 40-pin communications chip used on the I/O board and in the communications interface of the MCM/70 (an 8008-based computer) seen here.

SMC COM 2601

Why were these holes there, and how were they used?

(Side note: it's been pointed out that the auction description is probably not correct about this being used in any original Apple 1s.)

  • 4
    The question may not directly apply to any specific chip like the 6502, it may apply only to the package itself. The ceramic packages are usually bought from a company that manufactures them, and the silicon die that is put inside it can be anything. The holes might be for alignment, such as assisting in the manufacture of the ceramic package itself, or aligning the package in a machine that places the silicon chips in it, or bonds the wires, or seals the package with the top cover.
    – Justme
    Mar 10 '20 at 10:52
  • The actual chip is under the square bit with the lettering on it - that is the metal lid that is soldered on to the ceramic package. The stuff on either side is just filler to make the DIP package (and lead fan out) mechanically stable. The hole/slot, as noted above, are for aligning and manufacturing ease.
    – Jon Custer
    Mar 10 '20 at 12:57
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    I can't believe someone paid $800 for that thing!
    – jwh20
    Mar 10 '20 at 13:11
  • 1
    I don't have a source for this hunch, but those holes look a lot like anti-vibration mounts.
    – scruss
    Mar 11 '20 at 0:05
  • 1
    It's an unusual package for sure, but it was used for the AY-5-1012 too, at about the same time. Most packages have the leads brazed to the side, maybe this was more robust or easier to manufacture. As for the holes, since it was common to socket large IC's like this, maybe they were used to secure the package in the socket. Mar 18 '20 at 1:43

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