Magnetic Shielding and Packaging of STT MRAM

A magnetic shield was developed for the standard BGA MRAM DDRS chip to increase the magnetic interference tolerance from 100}}oe to more than 500 oetextbf{{. This enabled the low power and fast speed MRAM devices to operate in more rugged conditions. The shield used a soft ferromagnetic material to provide the passive shielding. In addition, the magnetic shield was a substrate level designed and it did not increase the package size significantly. This was expected to have a lower cost than the device level shielding which required to develop ferromagnetic material physical vapour deposition (spin coating, sputtering and plating) in the foundry.