Imec Vzw

Anne Jourdain

Eric Beyne

Gaspard Hiblot

Anabela Veloso

Douglas Charles La Tulipe

Nouredine Rassoul

A method producing a nano-sized interconnect structure that electrically connects the front side of a semiconductor substrate to the back side of the substrate is provided. In one aspect, the method produces a semiconductor component such as an integrated circuit chip that includes active devices formed on the front side of the substrate, and an interconnect network such as a power delivery network on the back side of the substrate. The substrate includes a lower semiconductor layer, an intermediate layer, and an upper layer. A trench is formed through the upper layer, the material of the intermediate layer is etched from inside the trench to form a cavity at the foot of the trench, and the trench and the cavity are filled with an electrically conductive material to form a buried rail with a wide contact pad at the foot of the rail, that is, wider than the width of the rail and extending between the front and back surfaces of the intermediate layer. A nanoTSV connection is processed from the back of the substrate, the nanoTSV contacting the contact pad, to thereby form the interconnect structure.

Interconnect structure of a semiconductor component and methods for producing the structure

A method of producing an IC chip is provided. In one aspect, deep trenches are formed in a semiconductor layer that forms the top layer of a device wafer, the trenches going through the complete thickness of the layer. The trenches are filled with a sacrificial material, that is etched back and covered with a capping layer, thereby forming sacrificial buried rails. After processing active devices on the front surface of the semiconductor layer, including connections to the sacrificial rails, the device wafer is bonded face down to a carrier wafer, and thinned from the back side, until the sacrificial rails are exposed. The sacrificial material and the capping layer are removed and replaced by a conductive material, thereby forming the actual buried power rails. A back side power delivery network supplies power through the buried rails to the active devices of the IC. Using a sacrificial material for the buried rails can enable a wider choice of materials for these buried rails.

Method of producing an integrated circuit chip including a back-side power delivery network

A method for producing an integrated circuit (IC) chip on a semiconductor device wafer is disclosed. In one aspect, the IC chip includes buried interconnect rails in the front end of line and a power delivery network (PDN) on the back side of the chip. The PDN is connected to the front side by micro-sized through semiconductor via (TSV) connections through the thinned semiconductor wafer. The production of the TSVs is integrated in the process flow for fabricating the interconnect rails, with the TSVs being produced in a self-aligned manner relative to the interconnect rails. After bonding the device wafer to a landing wafer, the semiconductor layer onto which the active devices of the chip have been produced is thinned from the back side, and the TSVs are exposed. The self-aligned manner of producing the TSVs enables scaling down the process towards smaller dimensions without losing accurate positioning of the TSVs.

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Grez Doiceau, Belgium

Anne Jourdain