ask a question about top metal

in layout , a small ring using top metal connects signal line ,why?

sorry,I don't know how to show my picture here. I show it :
# represent top metal


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You can easy to change signal routing by FIB when IC debug.

for trim

Can you show it to us,that may be helpful.

Regards

flyankh

Muldersun has right. Is for laser trimming on chip. In this way you can modify series resistance, for a better matching of the two signal paths.

Thank you . But it appears not only in analog layout but in digital layout as well. and it's not only a small ring but also a block metal (size 5um*5um) connecting signal lines.

O.K. I've got it !!
The are "touch-points" for microprobing de-passified parts.

Thank you. I don't find probe windows (pad layer) at the top of metal. and in the digital layout ,there are 118 blocks of metal (area 5um*5um). I'm not sure that the metal is for microprobe.
* represent top metal

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