I have these ceramic CPU with non gold cap, is there any other pm in these metal caps, or just remove them..
PaulView attachment 63846
Yes these have gold bondwires, hard to see at the pictureView attachment 63972
I completely forgot about this... You are right. Worth to check. Dip-tin covered lids could be previously plated as well. I experienced this a lot in the past when working with old "eastern block" "dip-tinned" metal-cap DIP ceramic IC´s. Even the top of the lid was "silver" in colour, it contained nice gold underneath.FYI, I found the below which is part of an old post by GSP. Although he was talking about ceramic DIP packages with gold plated caps, the materials used would be the same for a PGA package. The only question is whether a different braze might have been used for attaching non-gold plated caps?
GSP:
“On a sealed package, like that one, about 60%, or maybe more, of the value is in the 2 different gold brazes, neither of which looks much like gold. The 80%Au/20Sn, under the lid, is a pasty dark gray color, especially when heated in air, and the 96Au/4Si braze is a very light yellow color. Don't figure you have all the gold unless the chip is free to slide around. This only occurs after all the gold braze under the chip has been dissolved with aqua regia.”
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