Metal Pad Structure Over TSV to Reduce Shorting of Upper Metal Layer

摘要

Various embodiments of mechanisms for forming a slotted metal pad over a TSV in substrate are provided. The dielectric structures in the slotted metal pad reduce dishing effect during planarization of the slotted metal pad. As a result, the risk of having metal stringers in upper metal level(s) caused by the dishing effect is greatly reduced.

主权项

1. A method of forming interconnect structures over a through substrate via (TSV) on a substrate, comprising:
providing the substrate with the TSV; forming a dielectric layer over the TSV; forming openings in the dielectric layer, wherein the openings are connected, wherein there are dielectric structures of the dielectric layer amongst openings; depositing a diffusion barrier layer to line the openings; depositing a conductive layer to gap-fill the openings; and planarizing the conductive layer and the diffusion barrier layer to remove the conductive layer and the diffusion barrier layer outside the openings to form a slotted metal pad, wherein the planarization operation does not cause significant dishing effect near a center of the slotted metal pad.