HP-71b CMT-64E Eprom - Whats under the black goop ?

[coitboy2000]

I have a few of these Eproms and decided to open one up to have a look. Sylvain has been kind enough to re-program some for me in the past. I was wondering what lies beneath the black dob of goop ? I guess an integrated circuit to account for the lack of 32 pins (13 only on module, 32 on PLCC32 eprom) ? I am going to try and program the eprom as a bit of a learning exercise with an Arduino Mega. Just curious whats underneath and how you might remove the black material.

Cheers

Richard