Why inductors must be in upper metal layer in a LNA desing?

[adamantiumxx]

I have a lot of dudes about LNA design, but among lots of them is Why INductors must be placed Over the last metal layer in a LNA Design?

there are lots of models of iductors but always find that inductors are in last metal layer in each paper thet i read.

thanks.

 

[JoannesPaulus]

the top layers are thicker, i.e. have lower resistance, and therefore better Q.

 

[deepak242003]

moreover,they are most apart from substrate.. means less noise coupling......