Improve the Shielding Effectiveness of a BGA Package by Using VSS Ring Structure

I/O pin counts have been able to increase significantly thanks to ball grid array (BGA) packages. This I/O pin counts increase brings challenges to break out signals and ensure sufficient shielding effectiveness (SE). Shielding can is often used to enhance the SE of the package but in many devices, conformal sputtering shielding is a better option. This paper presents a method to improve the SE by adding a VSS ground ring structure to the sputtering coat. The simulated results show the proposed structure provides 20 dB more SE compare to the structure without a VSS ground ring.