Extended under-bump metal layer for blocking alpha particles in a semiconductor device
AssigneeXilinx, Inc.
InventorMichael J. Hart
Life of this patent
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Abstract
An integrated circuit (IC) has an under-bump metal (UBM) pad disposed between a solder bump and a semiconductor portion of the IC. A UBM layer is disposed between the solder bump and the semiconductor portion and includes the UBM pad and a UBM field. The UBM pad has a contact perimeter formed with the solder bump. The UBM pad extends beyond the contact perimeter a sufficient distance to block alpha particles emitted from the surface of the solder bump from causing an upset event in the semiconductor portion. The UBM field is separated from each UBM pad by a gap extending from the UBM pad to the UBM field so as to electrically isolate the UBM field from the UBM pad.
Claims12
An integrated circuit (IC), comprising:
- a plurality of solder bumps, each solder bump having a surface;
- a semiconductor portion;
- a UBM layer disposed between the solder bumps and the semiconductor portion and including a plurality of under-bump metal (UBM) pads and a UBM field;
- wherein each UBM pad is disposed between a respective one of the solder bumps and the semiconductor portion, and the UBM pad has a contact perimeter formed with the respective solder bump,
- wherein each UBM pad extends over a passivation layer, over a protective layer, and beyond the contact perimeter a sufficient distance to block alpha particles emitted from the surface of the solder bump from causing an upset event in the semiconductor portion;
- and
- wherein the UBM field is separated from each UBM pad by a gap extending from the UBM pad to the UBM field so as to electrically isolate the UBM field from the UBM pad;
- and
- a solder mask layer on each UBM pad that defines a contact aperture having the contact perimeter.
Dependencies are inferred from the claim text.