3D structure of an old IC using NA 0.75 versus NA 0.42

[rjlittlefield]

The subject here is a computer chip of unknown origin. It was given to me by a friend who decapsulated it, thought it was interesting, and gave it to me to photograph with my rig. The chip is apparently quite old, given the large size of both the chip and the elements on it.

The aluminum line widths here are about 5 microns wide, while the total depth of surface topology is about 2.5 microns. The chip as a whole is about 8000 microns long, so if you look at the whole chip it just looks like a flat surface with a pattern printed on it. But, if you zoom in to a small enough field using optics with enough depth resolution, there is some interesting 3D structure in the form of aluminum traces crisscrossing each other and building up thickness. That's what we're looking at here.

First, a rocking animation for those who can't see stereo.



Then a static crossed-eye stereo pair. This and the animation above were shot at about 23X, using a nominal 20X NA 0.75 objective. For me this does a good job of representing the 3D structure.



Following is much less successful stereo pair of the same place on the same subject, shot at about 21X using a nominal 20X NA 0.42 objective. For me the 3D structure of this one is definite but pretty murky.



The two source frames below show the reason for the difference in success of the 3D views. Compared to NA 0.42 on the right, NA 0.75 on the left has about 1.8 times better lateral resolution and over 3 times higher depth resolution. (Depth resolution goes as the square of the NA.) That improved depth resolution in the source images translates directly to improved clarity on the 3D rendering.

Warning: the following is NOT a stereo pair!





The whole frame can be explored in stereo using the Zerene viewer, HERE.

Shot with Canon R7 camera using (1) Nikon Plan Apo 20X NA 0.75 on Raynox DCR-150 with extra 4 cm of extension to compensate for no cover glass, and (2) Mitutoyo M Plan Apo 20X NA 0.42, both using epi-brightfield illumination with continuous LED. Step sizes of 0.25 µm for NA 0.75 and 1 µm for NA 0.42.

--Rik

[Sym P. le]

Fascinating! You display the capabilities of the objectives very well.

As an anecdotal aside, a few months ago, a friend asked me to show him some of my macro lenses and I quickly obliged. I showed him my Plan Apo, but not attached to any setup, just hand held so he could see his finger print and a business card. It's difficult to tell if normies are impressed or not. Long story short, you've now given me plenty of examples to show others what this objective can do (and in my own interest, how it performs relative to the Mitty). Unfortunately I have to tell my friends "This is what Rik can do with this objective!"

Cheers.

[Lou Jost]

It's difficult to tell if normies are impressed or not.

This made my day.