nRF5340 WLCSP Soldermask Defined (SMD) Pad Footprint

[Kyle]

Hi,

Our substrate manufacturer and assembly house are both strongly recommending soldermask defined pads for the WLCSP package.  Can you please recommend a soldermask opening size and/or share the diameter of the metallization on the die's UBM layer?

Thank you,

Kyle

[Jennifer Gibbs]

Hello Kyle,

Have you reviewed the reference designs for the WLCSP CLAA and CMAA packages? 

https://nsscprodmedia.blob.core.windows.net/prod/software-and-other-downloads/reference-layouts/nrf5340/nrf5340-xxaa-reference-layout-1_2.zip

You should be able to find what you need in the CLAA and/or CMAA layout gerber files depending on the package you are using.

Thank you,

Jennifer Gibbs

[Kyle]

Hi Jennifer, thanks for the link.  I did look at the production files in the zip archive, but they are for non-soldermask-defined pads:

Do you have recommendations for soldermask-defined?

Best

Kyle