Help: on chip inductor layout?

inductor layout

Hi,

Is anyone here have any experience on on-chip layout? Please help me out ...

1. Does the inductor layout need substrate contact which ties to ground? Why and Why not?

2. Does the inductor need n-well under it?

3. Does the PGS (Patternedound Shield) need to be tied to ground pad through metals, or just tie it to the substrate?

4. Please refer to the attached pix. It's from an JSSC paper of Hung-Wei Chiu's, publised this year. I'm wondering what's those stuff indicated by(1) and (2)? (the white block under the inductors and capacitors -- (1), and those rectangle shape black blocks--(2))

Thank you.

Ruri

yeah it need substarte contacts near it , to minimize the substarte coupling from the inductor , usually adding many substate contacts

about the n well , it is better to use a low high resitive well or low doped well
this will decrease the substare loss , and the well act as a reverse biased juction which will decrease the substarte coupling

about the PGS , i donot know u can tie it to ground with metal


which this help

khouly

Hi,

Substrate contact reduces usually the Eddy Current within the substrate with low resistivity and increases the quality factor of the inductor. However there are some important layout considerations when placing the substrate contacts. For example, the substrate contact should not form a closed loop around the inductor, otherwise your inductor will be asymmetric (S11 != S22).

Your PGS should be connected to the ground to isolate your inductor from the substrate.

The area under the inductor is white, because he has just eliminated the dummy generation, I think (but I'm not sure). In this way, you don't have dummy metal structures or p-wells under your inductor, that may degrade your quality factor.

please refer to papers from Burghartz or Tiebout, they are the best.

good luck

Hi, thanks for your reply.

Based on those materials I've read these two days, I found that it might be better with the substrate contact around the inductors, and the PGS do need to be tied to ground.

Thanks.

Ruri