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what is "pickup"?

sleepy_shiba

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Hi everyone,

I work in a IC design house with a lot of old Asian engineers, they always say "sub pickup", "body pickup". When I asked them what is "pickup" they just pointed at the subtract.
Is there anyone can tell me what exactly is "pickup", "sub pickup"and "body pickup"?
I couldn't find any definition on the internet.
PS: when they say "pickup" I can only think of the truck, and also the internet as well haha

BR,
Kalinda.
 

wwfeldman

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i now nothing about IC design
however, from what you wrote, i assume pickup means the stuff removed by an etch(?) step (the subtract)

hence sub pickup might be substrate stuff removed
and body pickup might be stuff removed from a feature or some part of a feature
 

timof

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Here is how I understand "pickup", in this context.

Suppose that two nodes (nets) in IC design are supposed to be completely decoupled - i.e. thay are supposed not to "see", not to "feel" each other.
I.e. when voltage or current on/in one of the net changes - this does not affect the other net.

But in reality, in physical implementation of IC, parasitic elements - parasitic resistors in the metallization, parasitic capacitances between nets, parasitics resistive and capacitive (mostly p-n junctions) elements in the substrate, parasitic inductances and inductive loops - lead to interaction between the nets.

So, when a noisy net changes its voltage or current, it affects other nets, coupled (by parasticis) to it - and their electrical conditions (voltage, current, etc.) change, in response.

This unintended coupling and electrical change, caused by other nets, is called "pickup".
 

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