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Table of Contents
Backside analysis can include:
- Imaging transistor layout without delayering
- Imaging transistor activity using PMT, camera, etc for side channnel analysis
- Laser fault injection, bypassing security meshes and other things usually in the way
Fabs often thin wafers and perform backside analysis to get at the transistors without going through metal. [Functional IC Analysis] doesn't look like they thinned and they got pretty decent results.
Camera
mcmaster: I bought an MU800 with the intention of removing the IR filter. I also might put silicon wafer in the imaging path to filter out the visible light. Unclear if my microscope optics can pass the IR light, say, even the relay lens. But I suppose if they have an IR filter it must pass some?
Ordering some IR lasers
Sample commercial unit
With IR imaging and laser fault injection
Camera:
- uEeye Cockpit
- ueye IDS camera
- U124xSE-NIR
- Or maybe: UI24xSE-NIR
- think its standard camera they removed IR filter
Optical fault injection
Above: “FIGURE 3.1 Transmission spectrum of crystalline silicon from the visible to the near-IR.” (source)
In its simplest form, a CSP can be strobed with a camera flash
You need to excite the silicon with a photo of wavelength no more than 1.1 um (reference: “1234.5eV⋅nm/1.1eV is about 1100 nm. Putting 1100 back into the denominator yields 1.1 eV” (link))
Sergei paper references using 1065 nm laser. The paper shows using IR objectives. So maybe a broadband source would work okay too.
Solutions include:
- ChipWispherer has voltage glitching. Could probably rig something similar up for optical glitching
