Commissariat &#xc0; L'&#xc9;nergie Atomique Et Aux &#xc9;nergies Alternatives

Paul Gondcharton

Bruno Imbert

Lamine Benaissa

Hubert Moriceau

Chiara Sabbione

Guillaume Rodriguez

Anne-Marie Charvet

A method includes steps a) providing the first structure successively including a first substrate, a first layer made from a metal base and a first metal-based metal oxide, b) providing the second structure successively including a second substrate, a second layer made from a second material and a second metal-based metal oxide, the first and second metal oxides presenting a standard free enthalpy of formation &#x394;G&#xb0;, the second material being chosen so that it has an oxide presenting a standard free enthalpy of formation strictly less than &#x394;G&#xb0;, c) bonding the first structure and second structure by direct adhesion, d) activating diffusion of the oxygen atoms of the first and second metal oxides to the second layer so as to form the oxide of the second material.

Method for adhering a first structure and a second structure

A method for manufacturing a heterostructure, including: contacting a first substrate having a first coefficient of thermal expansion and a second substrate having a different second coefficient of thermal expansion; annealing an assembly formed by contacting the first substrate and the second substrate; after annealing, returning the assembly to room temperature; providing, before the contacting, at least one intermediate layer at a surface of at least one of the first and second substrates, the at least one intermediate layer being made of a material which is ductile during the annealing and returning to room temperature; performing the contacting with the at least one intermediate layer sandwiched between the first and the second substrates; upon returning to room temperature, applying an outer pressure to the assembly to maintain it compressed.

Method for assembling two substrates of different natures via a ductile intermediate layer

A method for assembling a first substrate and a second substrate by metal-metal direct bonding, includes providing a first layer of a metal at the surface of the first substrate and a second layer of the metal at the surface of the second substrate, the first and second metal layers having a tensile stress (&#x3c3;) between 30% and 100% of the tensile yield strength (&#x3c3;) of the metal; assembling the first and second substrates at a bonding interface by directly contacting the first and second tensile stressed metal layers; and subjecting the assembly of the first and second substrates to a stabilization annealing at a temperature lower than or equal to a temperature threshold beyond which the first and second tensile stressed metal layers are plastically compressively deformed.

Metal-metal direct bonding method

A bonding between a first substrate and a second substrate, the method includes the steps of: a) providing the first substrate and the second substrate, b) forming a first bonding layer having tungsten oxide on the first substrate and a second bonding layer having tungsten oxide on the second substrate, at least one of the first bonding layer and of the second bonding layer including a third element M so as to form an MWxOy-type alloy, the atomic content of M in the composition of the alloy being between 0.5 and 20% and preferably between 1 and 10%, c) carrying out a direct bonding between the first bonding layer and the second bonding layer, and d) performing a heat treatment at a temperature greater than 250&#xb0; C.

Direct bonding method

A method for assembling a first substrate and a second substrate via metal adhesion layers, the method including: depositing, on a surface of each of the first and second substrates, a metal layer with a thickness controlled to limit surface roughness of each of the deposited metal layers to below a roughness threshold; exposing the metal layers deposited on the surface of the first and second substrates to air; directly adhering the first and second substrates by placing the deposited metal adhesion layers in contact, the surface roughness of the contacted layers being that obtained at an end of the depositing. The adhesion can be carried out in the air, at atmospheric pressure and at room temperature, without applying pressure to the assembly of the first and second substrates resulting from directly contacting the deposited metal adhesion layers.

Method for direct adhesion via low-roughness metal layers

A process for obtaining a bonding surface for direct bonding includes: a) providing a substrate based on a sintered metal having a base surface with an RMS roughness lower than 6 nanometers and a PV roughness lower than 100 nanometers; b) bombarding the base surface with ionic species; c) depositing a metal layer on the base surface; and d) carrying out a mechanical and/or chemical polish of an exposed surface of the metal layer. A structure including a substrate based on a sintered metal the base surface of which is at least partially formed from a metal including ionic species implanted by bombardment of the base surface, and a metal layer of identical chemical composition to that of the metal base substrate and including a bonding surface with an RMS roughness lower than 0.6 nanometers and a PV roughness lower than 10 nanometers is also provided.

Method for obtaining a bonding surface for direct bonding

A method for producing a structure by direct bonding of two elements, the method including: production of the elements to be assembled and assembly of the elements. The production of the elements to be assembled includes: deposition on a substrate of a TiN layer by physical vapor deposition, and deposition of a copper layer on the TiN layer. The assembly of the elements includes: polishing the surfaces of the copper layers intended to come into contact so that they have a roughness of less than 1 nm RMS and hydrophilic properties, bringing the surfaces into contact, and storing the structure at atmospheric pressure and at ambient temperature.

Process for producing a structure by assembling at least two elements by direct adhesive bonding

A method for manufacturing a structure implementing temporary bonding a substrate to be handled with a handle substrate, including: providing the substrate to be handled covered with a first metal layer, the first layer having a first grain size; providing the handle substrate covered with a second metal layer, the second layer having same composition as the first metal layer and a second grain size different from the first grain size; assembling the substrate to be handled and the handle substrate by thermocompression assisted direct bonding on the first and second metal layers; possibly treating the substrate to be handled assembled to the handle substrate; disassembling the assembly of the substrate to be handled and the handle substrate to form the structure, including an embrittlement thermal annealing of the assembly resulting in the handle substrate being detached.

Process for manufacturing a semiconductor structure with temporary bonding via metal layers

A method includes a) Providing a first substrate covered by a metal layer and a second substrate covered by a metal layer, b) Bringing into direct contact the metal layers so as to form a bonding interface having metal material bridges separated by cavities which are fluidly connected to each other, d) Immersing the bonding interface in an oxidizing fluid so as to form a metal oxide which fills at least in part the cavities and metal/metal oxide/metal contact areas. A structure is also provided having a first substrate, a first metal layer, a second metal layer forming a bonding layer with the first metal layer, and a second substrate, the bonding interface having: metal material bridges separated by cavities, a metal oxide partially filling the cavities, and metal/metal oxide/metal contact areas.

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Grenoble, France

Paul Gondcharton