A method of forming bump protective collars is disclosed. A wafer has an active surface with a plurality of bonding pads and a passivation layer. A plurality of reflowed bumps are formed over the bonding pads. A photoresist is coated on the active surface. Using the reflowed bumps as a photo mask, the photoresist is exposed and developed. After removing the photoresist, a plurality of bump protective collars are formed on the passivation layer and around the reflowed bumps for improving the reliability of the reflowed bumps.