You'll need a REALLY LONG T-15! I found a longish
1/4 inch
hex-drive Torx bit and a slender 1/4 inch hex extender. If
you're very lucky/keen, you can get a special Mac
screwdriver with is T-15 and about two feet long!
I know - I'm hoping my extender is slender enough :)
If you're absolutely sure it's a dead chip,
the safest way
to replace it is to snip all the legs off, one by one, and
then unsolder them. Your goal is to save the (unique) PCB
and replace the (not unique) chip. PCB foil will come
unstuck if heated for a while, especially on cheaper PCBs,
such as were used in early 1980s home computers...
....and then replace it with a chip socket followed by working chip?