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Backside analysis can include:
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.
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
With IR imaging and laser fault injection
Camera:
Basic idea: change how the circuit switches current in order to introduce a glitch. For a combinitorial circuit you probably want a CW laser to keep the glitch active. If its a CPU, you probably want a pulsed laser to trigger the glitch for a short period of time
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.
Above: silicon transmission marked with bandgap and for 980 nm laser (commonly available)
Possible sources:
Commercial solutions include: