A multi-chip unit suitable for chip-level packaging may include multiple IC chips that are interconnected through a metal redistribution structure, and that are directly bonded to an integrated heat spreader. Bonding of the integrated heat spreader to the multiple IC chips may be direct so that no thermal interface material (TIM) is needed, resulting in a reduced bond line thickness (BLT) and lower thermal resistance. The integrated heat spreader may further serve as a structural member of the multi-chip unit, allowing a second side of the redistribution structure to be further interconnected to a host by solder interconnects. The redistribution structure may be fabricated on a sacrificial interposer that may facilitate planarizing IC chips of differing thickness prior to bonding the heat spreader. The sacrificial interposer may be removed to expose the RDL for further interconnection to a substrate without the use of through-substrate vias.

A multi-chip unit suitable for chip-level packaging may include multiple IC chips that are interconnected through a metal redistribution structure, and that are directly bonded to an integrated heat spreader. Bonding of the integrated heat spreader to the multiple IC chips may be direct so that no thermal interface material (TIM) is needed, resulting in a reduced bond line thickness (BLT) and lower thermal resistance. The integrated heat spreader may further serve as a structural member of the multi-chip unit, allowing a second side of the redistribution structure to be further interconnected to a host by solder interconnects. The redistribution structure may be fabricated on a sacrificial interposer that may facilitate planarizing IC chips of differing thickness prior to bonding the heat spreader. The sacrificial interposer may be removed to expose the RDL for further interconnection to a substrate without the use of through-substrate vias.

A semiconductor package includes a first connection structure, a first semiconductor chip on an upper surface of the first connection structure, a first molding layer on the upper surface of the first connection structure and surrounding the first semiconductor chip, a first bond pad on the first semiconductor chip, a first bond insulation layer on the first semiconductor chip and the first molding layer and surrounding the first bond pad, a second bond pad directly contacting the first bond pad, a second bond insulation layer surrounding the second bond pad; and a second semiconductor chip on the second bond pad and the second bond insulation layer.

A semiconductor package includes a first connection structure, a first semiconductor chip on an upper surface of the first connection structure, a first molding layer on the upper surface of the first connection structure and surrounding the first semiconductor chip, a first bond pad on the first semiconductor chip, a first bond insulation layer on the first semiconductor chip and the first molding layer and surrounding the first bond pad, a second bond pad directly contacting the first bond pad, a second bond insulation layer surrounding the second bond pad; and a second semiconductor chip on the second bond pad and the second bond insulation layer.

This method for producing a structure wherein base materials are bonded by atomic diffusion comprises: a step for applying a liquid resin on the base material; a step for smoothing the surface of the liquid resin by surface tension; a step for forming a resin layer by curing; a step for forming a metal thin film on the resin layer; a step for forming a metal thin film on the base material; and a step for bringing the metal thin film of the base material and the metal thin film of the base material into close contact with each other, thereby bonding the metal thin film of the resin layer and the metal thin film of the base material with each other by atomic diffusion.

This method for producing a structure wherein base materials are bonded by atomic diffusion comprises: a step for applying a liquid resin on the base material; a step for smoothing the surface of the liquid resin by surface tension; a step for forming a resin layer by curing; a step for forming a metal thin film on the resin layer; a step for forming a metal thin film on the base material; and a step for bringing the metal thin film of the base material and the metal thin film of the base material into close contact with each other, thereby bonding the metal thin film of the resin layer and the metal thin film of the base material with each other by atomic diffusion.

A semiconductor package includes: a first structure having a first insulating layer disposed on one surface, and first electrode pads and first dummy pads penetrating through the first insulating layer, a second structure having a second insulating layer having the other surface bonded to the one surface and the first insulating layer and disposed on the other surface, and second electrode pads and second dummy pads that penetrate through the second insulating layer, the second electrode pads being bonded to the first electrode pads, respectively, and the second dummy pads being bonded to the first dummy pads, respectively. In the semiconductor chip, ratios of surface areas per unit area of the first and second dummy pads to the first and second insulating layers on the one surface and the other surface gradually decrease toward sides of the first and second structures.

A semiconductor package includes: a first structure having a first insulating layer disposed on one surface, and first electrode pads and first dummy pads penetrating through the first insulating layer, a second structure having a second insulating layer having the other surface bonded to the one surface and the first insulating layer and disposed on the other surface, and second electrode pads and second dummy pads that penetrate through the second insulating layer, the second electrode pads being bonded to the first electrode pads, respectively, and the second dummy pads being bonded to the first dummy pads, respectively. In the semiconductor chip, ratios of surface areas per unit area of the first and second dummy pads to the first and second insulating layers on the one surface and the other surface gradually decrease toward sides of the first and second structures.

A method of removing a substrate, comprising: forming a growth restrict mask with a plurality of striped opening areas directly or indirectly upon a GaN-based substrate; and growing a plurality of semiconductor layers upon the GaN-based substrate using the growth restrict mask, such that the growth extends in a direction parallel to the striped opening areas of the growth restrict mask, and growth is stopped before the semiconductor layers coalesce, thereby resulting in island-like semiconductor layers. A device is processed for each of the island-like semiconductor layers. Etching is performed until at least a part of the growth restrict mask is exposed. The devices are then bonded to a support substrate. The GaN-based substrate is removed from the devices by a wet etching technique that at least partially dissolves the growth restrict mask. The GaN substrate that is removed then can be recycled.

A method of removing a substrate, comprising: forming a growth restrict mask with a plurality of striped opening areas directly or indirectly upon a GaN-based substrate; and growing a plurality of semiconductor layers upon the GaN-based substrate using the growth restrict mask, such that the growth extends in a direction parallel to the striped opening areas of the growth restrict mask, and growth is stopped before the semiconductor layers coalesce, thereby resulting in island-like semiconductor layers. A device is processed for each of the island-like semiconductor layers. Etching is performed until at least a part of the growth restrict mask is exposed. The devices are then bonded to a support substrate. The GaN-based substrate is removed from the devices by a wet etching technique that at least partially dissolves the growth restrict mask. The GaN substrate that is removed then can be recycled.