Abstract: Devices and techniques including process steps make use of recesses in conductive interconnect structures to form reliable low temperature metallic bonds. A fill layer is deposited into the recesses prior to bonding. First conductive interconnect structures are bonded at ambient temperatures to second metallic interconnect structures using direct bonding techniques, with the fill layers in the recesses in one or both of the first and second interconnect structures.

Abstract: Direct-bonded LED arrays and applications are provided. An example process fabricates a LED structure that includes coplanar electrical contacts for p-type and n-type semiconductors of the LED structure on a flat bonding interface surface of the LED structure. The coplanar electrical contacts of the flat bonding interface surface are direct-bonded to electrical contacts of a driver circuit for the LED structure. In a wafer-level process, micro-LED structures are fabricated on a first wafer, including coplanar electrical contacts for p-type and n-type semiconductors of the LED structures on the flat bonding interface surfaces of the wafer. At least the coplanar electrical contacts of the flat bonding interface are direct-bonded to electrical contacts of CMOS driver circuits on a second wafer.

Abstract: A bonding method can include activating a first bonding layer of a first element for direct bonding to a second bonding layer of a second element. The bonding method can include, after the activating, providing a protective layer over the activated first bonding layer of the first element.

Abstract: A bonding method can include polishing a first bonding layer of a first element for direct bonding, the first bonding layer comprises a first conductive pad and a first non-conductive bonding region. After the polishing, a last chemical treatment can be performed on the polished first bonding layer. After performing the last chemical treatment, the first bonding layer of the first element can be directly bonded to a second bonding layer of a second element without an intervening adhesive, including directly bonding the first conductive pad to a second conductive pad of the second bonding layer and directly bonding the first non-conductive bonding region to a second nonconductive bonding region of the second bonding layer. No treatment or rinse is performed on the first bonding layer between performing the last chemical treatment and directly bonding.

Abstract: Dies and/or wafers including conductive features at the bonding surfaces are stacked and direct hybrid bonded at a reduced temperature. The surface mobility and diffusion rates of the materials of the conductive features are manipulated by adjusting one or more of the metallographic texture or orientation at the surface of the conductive features and the concentration of impurities within the materials.

Abstract: A method for forming an interconnect structure in an element is disclosed. The method can include patterning a cavity in a non-conductive material. The method can include exposing a surface of the cavity in the non-conductive material to a surface nitriding treatment. The method can include depositing a conductive material directly onto the treated surface after the exposing.

Abstract: Structures and techniques provide bond enhancement in microelectronics by trapping contaminants and byproducts during bonding processes, and arresting cracks. Example bonding surfaces are provided with recesses, sinks, traps, or cavities to capture small particles and gaseous byproducts of bonding that would otherwise create detrimental voids between microscale surfaces being joined, and to arrest cracks. Such random voids would compromise bond integrity and electrical conductivity of interconnects being bonded. In example systems, a predesigned recess space or predesigned pattern of recesses placed in the bonding interface captures particles and gases, reducing the formation of random voids, thereby improving and protecting the bond as it forms. The recess space or pattern of recesses may be placed where particles collect on the bonding surface, through example methods of determining where mobilized particles move during bond wave propagation.

Abstract: Direct bonded stack structures for increased reliability and improved yields in microelectronics are provided. Structural features and stack configurations are provided for memory modules and 3DICs to reduce defects in vertically stacked dies. Example processes alleviate warpage stresses between a thicker top die and direct bonded dies beneath it, for example. An etched surface on the top die may relieve warpage stresses. An example stack may include a compliant layer between dies. Another stack configuration replaces the top die with a layer of molding material to circumvent warpage stresses. An array of cavities on a bonding surface can alleviate stress forces. One or more stress balancing layers may also be created on a side of the top die or between other dies to alleviate or counter warpage. Rounding of edges can prevent stresses and pressure forces from being destructively transmitted through die and substrate layers. These measures may be applied together or in combinations in a single package.

Abstract: A microelectronic assembly includes a first substrate having a surface and a first conductive element and a second substrate having a surface and a second conductive element. The assembly further includes an electrically conductive alloy mass joined to the first and second conductive elements. First and second materials of the alloy mass each have a melting point lower than a melting point of the alloy. A concentration of the first material varies in concentration from a relatively higher amount at a location disposed toward the first conductive element to a relatively lower amount toward the second conductive element, and a concentration of the second material varies in concentration from a relatively higher amount at a location disposed toward the second conductive element to a relatively lower amount toward the first conductive element.

Abstract: Representative implementations of techniques and devices provide seals for sealing the joints of bonded microelectronic devices as well as bonded and sealed microelectronic assemblies. Seals are disposed at joined surfaces of stacked dies and wafers to seal the joined surfaces. The seals may be disposed at an exterior periphery of the bonded microelectronic devices or disposed within the periphery using the various techniques.

Abstract: Dies and/or wafers including conductive features at the bonding surfaces are stacked and direct hybrid bonded at a reduced temperature. The surface mobility and diffusion rates of the materials of the conductive features are manipulated by adjusting one or more of the metallographic texture or orientation at the surface of the conductive features and the concentration of impurities within the materials.

Abstract: Devices and techniques including process steps make use of recesses in conductive interconnect structures to form reliable low temperature metallic bonds. A fill layer is deposited into the recesses prior to bonding. First conductive interconnect structures are bonded at ambient temperatures to second conductive interconnect structures using direct bonding techniques, with the fill layers in the recesses in one or both of the first and second interconnect structures.

Abstract: Dies and/or wafers are stacked and bonded in various arrangements including stacks, and may be covered with a molding to facilitate handling, packaging, and the like. In various examples, the molding may cover more or less of a stack, to facilitate connectivity with the devices of the stack, to enhance thermal management, and so forth.

Abstract: Representative techniques and devices, including process steps may be employed to mitigate undesired dishing in conductive interconnect structures and erosion of dielectric bonding surfaces. For example, an embedded layer may be added to the dished or eroded surface to eliminate unwanted dishing or voids and to form a planar bonding surface. Additional techniques and devices, including process steps may be employed to form desired openings in conductive interconnect structures, where the openings can have a predetermined or desired volume relative to the volume of conductive material of the interconnect structures. Each of these techniques, devices, and processes can provide for the use of larger diameter, larger volume, or mixed-sized conductive interconnect structures at the bonding surface of bonded dies and wafers.

Abstract: Layer structures for making direct metal-to-metal bonds at low temperatures and shorter annealing durations in microelectronics are provided. Example bonding interface structures enable direct metal-to-metal bonding of interconnects at low annealing temperatures of 150° C. or below, and at a lower energy budget. The example structures provide a precise metal recess distance for conductive pads and vias being bonded that can be achieved in high volume manufacturing. The example structures provide a vertical stack of conductive layers under the bonding interface, with geometries and thermal expansion features designed to vertically expand the stack at lower temperatures over the precise recess distance to make the direct metal-to-metal bonds. Further enhancements, such as surface nanotexture and copper crystal plane selection, can further actuate the direct metal-to-metal bonding at lowered annealing temperatures and shorter annealing durations.

Abstract: A method for forming an interconnect structure in an element is disclosed. The method can include patterning a cavity in a non-conductive material. The method can include exposing a surface of the cavity in the non-conductive material to a surface nitriding treatment. The method can include depositing a conductive material directly onto the treated surface after the exposing.

Abstract: Representative techniques provide process steps for forming a microelectronic assembly, including preparing microelectronic components such as dies, wafers, substrates, and the like, for bonding. One or more surfaces of the microelectronic components are formed and prepared as bonding surfaces. The microelectronic components are stacked and bonded without adhesive at the prepared bonding surfaces.

Abstract: Techniques are employed to mitigate the anchoring effects of cavity sidewall adhesion on an embedded conductive interconnect structure, and to allow a lower annealing temperature to be used to join opposing conductive interconnect structures. A vertical gap may be disposed between the conductive material of an embedded interconnect structure and the sidewall of the cavity to laterally unpin the conductive structure and allow uniaxial expansion of the conductive material. Additionally or alternatively, one or more vertical gaps may be disposed within the bonding layer, near the embedded interconnect structure to laterally unpin the conductive structure and allow uniaxial expansion of the conductive material.

Abstract: A first conductive material having a first hardness is disposed within a recess or opening of a microelectronic component, in a first preselected pattern, and forms a first portion of an interconnect structure. A second conductive material having a second hardness different from the first hardness is disposed within the recess or opening in a second preselected pattern and forms a second portion of the interconnect structure.

Abstract: Representative techniques and devices, including process steps may be employed to mitigate undesired dishing in conductive interconnect structures and erosion of dielectric bonding surfaces. For example, an embedded layer may be added to the dished or eroded surface to eliminate unwanted dishing or voids and to form a planar bonding surface. Additional techniques and devices, including process steps may be employed to form desired openings in conductive interconnect structures, where the openings can have a predetermined or desired volume relative to the volume of conductive material of the interconnect structures. Each of these techniques, devices, and processes can provide for the use of larger diameter, larger volume, or mixed-sized conductive interconnect structures at the bonding surface of bonded dies and wafers.