To get the die off the flip chip carrier I use heat and scraping. Then I use a razor blade to scrape off most of the metal layers (which obscure the functional blocks), then a cheap Chinese inspection microscope ($100) attached to a DSLR with a 3D printed adapter (a DSLR with a lens attached backwards also works in a pinch). Then take a bunch of individual photos and stitch them with Hugin.

Results: https://marcan.st/transf/latte_stitched.jpg

Edit: sorry, the link was previously the (lower res!) Chipworks shot I'd annotated previously. I got confused. Replaced with mine. It's less clean but higher resolution than what they released.

At the highest zoom I could get I could just about make out individual bits in the eFuse array. This is a Wii U GPU (Latte).

https://marcan.st/transf/latte_otp_slr.jpg

No chemicals needed. I'm probably one of very few people crazy enough to do this mechanically, but it clearly works!

Here's a single shot done with a reversed cheap kit Canon lens of a PS3 GPU (RSX), again with the scraping method.

https://marcan.st/transf/rsx.jpg

I do happen to have access to a SEM too, and obviously that gets a lot more fun. Here's the same eFuse area (again this is still the mechanically deprocessed chip!):

https://marcan.st/transf/sem/latte/20161210_201044.png

I think the mechanical delayering usually gets me to M1 or so, though it's not completely consistent depending on the specific process. Some chips work better than others.