Glop Top Question

[Tormenter]

What are under these glop top's on like mario NES boards? Can they be easily removed?

[lidnariq]

A bare silicon die. Wire bonding from the PCB to that die. Not much else.

In NES cartridges, the epoxy blobs are usually ROMs, with the same wire bond order as the legs would have had.

[tokumaru]

The same thing you'd find inside a regular DIP chip, but without any packaging. You cant remove the black stuff without destroying what's under it, AFAIK.

[mikejmoffitt]

The same thing you'd find inside a regular DIP chip, but without any packaging. You cant remove the black stuff without destroying what's under it, AFAIK.

I think it can be done with some harsh chemical work, but I don't think most people have that sort of material lying about.

[Memblers]

Yeah, when I worked at a chemical plant, I've blended some nasty mixtures used for this purpose. With stuff like methylene chloride and glacial acetic acid, don't even think about using that stuff without full respiratory, face, and skin protection. It's like vinegar from hell.

[Bregalad]

By the way the real name of this technology is "Chip on board", not "Glop Top" and it's extremely widely used in mass-produced consummer electronics, not just NES cartridges.

After too many units of a boards are produced, it's a waste of time and space to package all those chips when you could simply tie the chip to the board directly.

[loopy]

How Chip-On-Boards are Made

[Pokun]

Interesting! Thanks for the link.

[DNSDies]

Age can make those epoxy blobs very brittle.

I had a copy of Super Momotaro Densetu for PC Engine, and cannibalized the case to make a nice case for my TG16 Everdrive, so I thought I'd take off the protective plastic on the Hu-Card and take a look at the chips under it.

The act of bending the hu-card caused the epoxy blobs to literally disintegrate from the chip, leaving the bare silicon and wire bonding relatively unharmed.

It was pretty cool.