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backside:start [2018/02/20 21:24] – created mcmaster | backside:start [2018/02/20 21:54] – mcmaster | ||
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Fabs often thin wafers and perform backside analysis to get at the transistors without going through metal. | Fabs often thin wafers and perform backside analysis to get at the transistors without going through metal. | ||
- | Sample preparation example: | + | [[http:// |
====== Camera ====== | ====== Camera ====== | ||
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+ | 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? | ||
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+ | Ordering some IR lasers | ||
===== Sample commercial unit ===== | ===== Sample commercial unit ===== | ||
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====== Optical fault injection ====== | ====== Optical fault injection ====== | ||
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+ | 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 | ||
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+ | Above: " | ||
In its simplest form, a CSP can be strobed with a camera flash | In its simplest form, a CSP can be strobed with a camera flash | ||
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You need to excite the silicon with a photo of wavelength no more than 1.1 um (reference: " | You need to excite the silicon with a photo of wavelength no more than 1.1 um (reference: " | ||
- | [[Sergei paper|https:// | + | [[https:// |
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+ | {{: | ||
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+ | Above: silicon transmission marked with bandgap and for 980 nm laser (commonly available) | ||
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+ | Possible sources: | ||
+ | * Photo flash, such as with mask | ||
+ | * 980 nm laser will have high attenuation (roughly 2% transmittance), | ||
+ | * Specifically? | ||
+ | * 1065 nm (ie 1064 nm from Nd:YAG) and such is probably ideal | ||
+ | * Must Nd:YAG are flashlamp pumped | ||
+ | * Depending on glitch target might want either flashlamp or diode pumped | ||
[[https:// | [[https:// | ||
- | Solutions | + | Commercial solutions |
* [[http:// | * [[http:// | ||
* [[https:// | * [[https:// | ||
- | * ChipWispherer | + | * ChipWhispherer |