A structure includes a metal feature, and a passivation layer having a portion overlapping the metal feature. The passivation layer includes a non-low-k dielectric material. A polymer layer is over the passivation layer. A Post-Passivation Interconnect (PPI) extends into the polymer layer to electrically couple to the metal feature. A guard ring includes a second PPI, wherein the guard ring is electrically grounded. The second PPI substantially encircles the first PPI.