Method for forming copper pad redistribution and device formed
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorTze Liang Lee
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Abstract
A method for forming copper pad redistribution on a flip chip and structures formed by the method are disclosed. The method is compatible with a copper dual damascene process such that, after a substrate surface is planarized by chemical mechanical polishing, a single photomask can be used to pattern a plurality of redistribution pads, redistribution vias and redistribution lines. After the openings are filled with copper by an electroplating or an electroless plating technique, the top of the structure is again chemical mechanical polished to produce a planarized surface and resulting redistribution pads and redistribution lines. A sealing layer such as silicon nitride may be coated on the final structure as a moisture barrier.
Claims12
A method for forming copper pad redistribution comprising the steps of:
- providing a pre-processed semiconductor substrate having a first plurality of copper bond pads in a top surface,
- planarizing said semiconductor substrate by chemical mechanical polishing,
- forming a passivation layer on said planarized top surface of the semiconductor substrate,
- patterning and etching said passivation layer openings for a first plurality of redistribution vias, a first plurality of redistribution pads and a second plurality of redistribution lines connecting said first plurality of redistribution vias and said first plurality of redistribution pads by a dry etching method wherein sidewall passivation forms in openings of said plurality of redistribution lines stopping said etching in said passivation layer while opening for said first plurality of redistribution vias are etched through in said passivation layer to expose surfaces of said first plurality of copper bond pads,
- depositing copper into said openings for said first plurality of redistribution vias, said first plurality of redistribution pads and said second plurality of redistribution lines, and
- planarizing said semiconductor substrate forming said first plurality of redistribution vias and said second plurality of redistribution lines.
Dependencies are inferred from the claim text.