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May 23rd, 2022, 3:46pm
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Does metal (copper, aluminum) shielding really help inductors in ICs? (Read 137 times)
vlsi_design
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Does metal (copper, aluminum) shielding really help inductors in ICs?
Mar 31st, 2022, 11:29am
 
In ICs, the inductors can magnetically couple to the the substrate and cause eddy current to flow which causes power loss (emf^2/Rsub). To minimize this people put metal (copper, aluminum) shielding below the inductor to prevent magnetic lines of from from reaching substrate. Now the catch is both copper and aluminum have mu_r =1 i.e. they will pass all magnetic lines of force to the substrate. How can they help in shielding magnetic coupling? If iron were used then it might make sense but ICs do not use iron usually. Therefore, what is the mechanism?
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Frank Wiedmann
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Re: Does metal (copper, aluminum) shielding really help inductors in ICs?
Reply #1 - Apr 1st, 2022, 2:26am
 
I suggest that you take a look at https://www.sonnetsoftware.com/support/downloads/publications/EffPatGndShieldMod... and https://www.sonnetsoftware.com/support/downloads/publications/SiRFIC_Inductor_Si... (as well as https://www.youtube.com/watch?v=gDNp_TZQXcE if you like to get this narrated). This topic was also discussed in the article series "Patterned Ground Shields For Silicon RFICs" accessible from https://www.rfglobalnet.com/author/james-c-rautio.
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