Commissariat a L'energie Atomique Et Aux Energies Alternatives

Stmicroelectronics (Crolles 2) Sas

Viorel Balan

Maurice Rivoire

A structure includes a substrate having an upper surface provided with recesses and coated with a continuous barrier layer topped with a continuous copper layer filling at least the recesses. The structure is planarized by a chemical-mechanical polishing of the copper, such a polishing being selective with respect to the barrier layer so that copper remains in the recesses and is coplanar with the upper surface of the substrate. Two such structures are then direct bonded to each other (copper to copper) with opposite areas having a same topology.

Plurality of substrates bonded by direct bonding of copper recesses

A structure includes a substrate having an upper surface provided with recesses and coated with a continuous barrier layer topped with a continuous copper layer filling at least the recesses. The structure is planarized by: a) chemical-mechanical polishing of the copper, such a polishing being selective with respect to the barrier layer so that copper remains in the recesses and is set back with respect to the upper surface of the substrate; b) depositing on the exposed surface of the structure a material covering at least the copper at the level of the recesses; and c) chemical-mechanical planarizing of the structure to expose the substrate with the copper remaining buried under the material. Two such structures are then direct bonded to each other with opposite areas of material having a same topology.

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La Buisse, France

Viorel Balan