I thought the hole was to be through the circuit board, not the chip itself.? The substrate is silicon which is rather hard.? It has a Mohs hardness of about 7.? Titanium is less hard at 5 to 6 as a comparison.? Tungsten carbide 9.? The silicon wafer is also much harder than regular glass.

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You probably not only need something like a diamond drill as mentioned, but perhaps even a means to cool it.

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One other thing.? The silicon wafer at the beginning of the semiconductor manufacturing process is about 1 mm thick.? Many wafers, after the devices have been deposited on them, go through a "backgrinding" process to remove much of the silicon wafer to make it thinner.? Then it is sliced up into individual chips and then packaged.? Thinning helps with heat distribution.? (I know this stuff because I was involved in designing semiconducting manufacturing equipment).? Therefore, the substrate might actually be quite thin.

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Charles E. "Chuck" Kinzer

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