what happens to the spewed stuff?........

[Eric at Svetlana Electron Devices]

>. But I also recall that there are intergrated circuits
>that have their resistors trimmed up by laser. A-D's etc. Precision
>multipliers and the like. They trim the circuit up by shaving off the
>surface with a laser before packaging the die. I guess it's much the same
>thing. Which begs the question. "What happens to all the microscopic
>material they trim off with the laser?" Perhaps it just burns away or
something.

Nope, it just spews all over the chip and stays there. This is why there are
limits to how small you can make the devices on laser-trimmed chips.
Below a certain size (I think 50 microns), the devices have a real chance
of being shorted out by the debris from the trimming.
This is also why the fuse-programmed PROM is nearly dead as a
technology--you can't make the transistors as small as on an EPROM
or flash RAM, because the fuse debris just ends up splattered all over
the chip.

(so I read somewhere years ago.....can't remember where)

Eric Barbour
Svetlana Electron Devices
Portola Valley CA USA