A fluxless bonding process is provided. An array of micro solder bumps of a first semiconductor structure is aligned to an array of bonding pads of a second semiconductor structure under an applied bonding force. An environment is provided to prevent oxides from forming on the solder bump structures and bonding pads during the bonding process. A scrubbing process is performed at a given scrubbing frequency and amplitude to scrub the micro solder bumps against the bonding pads in a direction perpendicular to the bonding. Heat is applied to at least the first semiconductor structure to melt and bond the micro solder bumps to the bonding pads. The first semiconductor structure is cooled down to solidify the molten solder. Coplanarity is maintained between the bonding surfaces of the semiconductor structures within a given tolerance during the scrubbing and cooling steps until solidification of the micro solder bumps.

A fluxless bonding process is provided. An array of micro solder bumps of a first semiconductor structure is aligned to an array of bonding pads of a second semiconductor structure under an applied bonding force. An environment is provided to prevent oxides from forming on the solder bump structures and bonding pads during the bonding process. A scrubbing process is performed at a given scrubbing frequency and amplitude to scrub the micro solder bumps against the bonding pads in a direction perpendicular to the bonding. Heat is applied to at least the first semiconductor structure to melt and bond the micro solder bumps to the bonding pads. The first semiconductor structure is cooled down to solidify the molten solder. Coplanarity is maintained between the bonding surfaces of the semiconductor structures within a given tolerance during the scrubbing and cooling steps until solidification of the micro solder bumps.

A semiconductor device has an interposer mounted over a carrier. The interposer includes TSV formed either prior to or after mounting to the carrier. An opening is formed in the interposer. The interposer can have two-level stepped portions with a first vertical conduction path through a first stepped portion and second vertical conduction path through a second stepped portion. A first and second semiconductor die are mounted over the interposer. The second die is disposed within the opening of the interposer. A discrete semiconductor component can be mounted over the interposer. A conductive via can be formed through the second die or encapsulant. An encapsulant is deposited over the first and second die and interposer. A portion of the interposer can be removed to that the encapsulant forms around a side of the semiconductor device. An interconnect structure is formed over the interposer and second die.

The present disclosure relates to a flip-chip package with a hollow-cavity and reinforced interconnects, and a process for making the same. The disclosed flip-chip package includes a substrate, a reinforcement layer over an upper surface of the substrate, a flip-chip die attached to the upper surface of the substrate by interconnects through the reinforcement layer, an air cavity formed between the substrate and the flip-chip die, and a protective layer encapsulating the flip-chip die and defining a perimeter of the air cavity. Herein, a first portion of each interconnect is encapsulated by the reinforcement layer and a second portion of each interconnect is exposed to the air cavity. The reinforcement layer provides reinforcement to each interconnect.

The present disclosure relates to a flip-chip package with a hollow-cavity and reinforced interconnects, and a process for making the same. The disclosed flip-chip package includes a substrate, a reinforcement layer over an upper surface of the substrate, a flip-chip die attached to the upper surface of the substrate by interconnects through the reinforcement layer, an air cavity formed between the substrate and the flip-chip die, and a protective layer encapsulating the flip-chip die and defining a perimeter of the air cavity. Herein, a first portion of each interconnect is encapsulated by the reinforcement layer and a second portion of each interconnect is exposed to the air cavity. The reinforcement layer provides reinforcement to each interconnect.

A fluxless bonding process is provided. An array of micro solder bumps of a first semiconductor structure is aligned to an array of bonding pads of a second semiconductor structure under an applied bonding force. An environment is provided to prevent oxides from forming on the solder bump structures and bonding pads during the bonding process. A scrubbing process is performed at a given scrubbing frequency and amplitude to scrub the micro solder bumps against the bonding pads in a direction perpendicular to the bonding. Heat is applied to at least the first semiconductor structure to melt and bond the micro solder bumps to the bonding pads. The first semiconductor structure is cooled down to solidify the molten solder. Coplanarity is maintained between the bonding surfaces of the semiconductor structures within a given tolerance during the scrubbing and cooling steps until solidification of the micro solder bumps.

A fluxless bonding process is provided. An array of micro solder bumps of a first semiconductor structure is aligned to an array of bonding pads of a second semiconductor structure under an applied bonding force. An environment is provided to prevent oxides from forming on the solder bump structures and bonding pads during the bonding process. A scrubbing process is performed at a given scrubbing frequency and amplitude to scrub the micro solder bumps against the bonding pads in a direction perpendicular to the bonding. Heat is applied to at least the first semiconductor structure to melt and bond the micro solder bumps to the bonding pads. The first semiconductor structure is cooled down to solidify the molten solder. Coplanarity is maintained between the bonding surfaces of the semiconductor structures within a given tolerance during the scrubbing and cooling steps until solidification of the micro solder bumps.

Methods and systems for low-force, low-temperature thermocompression bonding. The present application teaches new methods and structures for three-dimensional integrated circuits, in which cold thermocompression bonding is used to provide reliable bonding. To achieve this, reduction and passivation steps are preferably both used to reduce native oxide on the contact metals and to prevent reformation of native oxide, preferably using atmospheric plasma treatments. Preferably the physical compression height of the elements is set to be only enough to reliably achieve at least some compression of each bonding element pair, compensating for any lack of flatness. Preferably the thermocompression bonding is performed well below the melting point. This not only avoids the deformation of lower levels which is induced by reflow techniques, but also provides a steep relation of force versus z-axis travel, so that a drastically-increasing resistance to compression helps to regulate the degree of thermocompression.

Methods and systems for low-force, low-temperature thermocompression bonding. The present application teaches new methods and structures for three-dimensional integrated circuits, in which cold thermocompression bonding is used to provide reliable bonding. To achieve this, reduction and passivation steps are preferably both used to reduce native oxide on the contact metals and to prevent reformation of native oxide, preferably using atmospheric plasma treatments. Preferably the physical compression height of the elements is set to be only enough to reliably achieve at least some compression of each bonding element pair, compensating for any lack of flatness. Preferably the thermocompression bonding is performed well below the melting point. This not only avoids the deformation of lower levels which is induced by reflow techniques, but also provides a steep relation of force versus z-axis travel, so that a drastically-increasing resistance to compression helps to regulate the degree of thermocompression.

Methods and systems for low-force, low-temperature thermocompression bonding. The present application teaches new methods and structures for three-dimensional integrated circuits, in which cold thermocompression bonding is used to provide reliable bonding. To achieve this, reduction and passivation steps are preferably both used to reduce native oxide on the contact metals and to prevent reformation of native oxide, preferably using atmospheric plasma treatments. Preferably the physical compression height of the elements is set to be only enough to reliably achieve at least some compression of each bonding element pair, compensating for any lack of flatness. Preferably the thermocompression bonding is performed well below the melting point. This not only avoids the deformation of lower levels which is induced by reflow techniques, but also provides a steep relation of force versus z-axis travel, so that a drastically-increasing resistance to compression helps to regulate the degree of thermocompression.