Backside warpage control structure and fabrication method

摘要

Through vias extend through a substrate between a frontside surface and a backside surface, the through vias comprising active surface ends at the frontside surface. A frontside redistribution structure is coupled to the active surface ends, the frontside redistribution structure exerting force on the frontside surface, e.g., due to a difference in the thermal coefficient of expansion (TCE) between the frontside redistribution structure and the substrate. To prevent warpage of the substrate, a backside warpage control structure is coupled to the backside surface of the substrate. The backside warpage control structure exerts an equal but opposite force to the force exerted by the frontside redistribution structure thus avoiding warpage of the substrate.

主权项

1. A structure comprising:
a substrate comprising:
a frontside surface;a backside surface; a through via extending through the substrate between the frontside surface and the backside surface, the through via comprising an active surface end at the frontside surface; a frontside redistribution structure coupled to the active surface end, the frontside redistribution structure exerting force on the frontside surface; a backside passivation layer coupled to the backside surface; a seed layer coupled to the backside passivation layer; a backside terminal layer plated directly on the seed layer; and a backside warpage control structure consisting of an electrically conductive layer plated on the seed layer, the backside warpage control structure exerting an opposing force to counter the force exerted by the frontside redistribution structure where a thickness of the plated backside terminal layer is different from a thickness of the plated electrically conductive layer.