A method includes forming a metal bump on a top surface of a first package component, forming a solder region on a top surface of the metal bump, forming a protection layer extending on a sidewall of the metal bump, reflowing the solder region to bond the first package component to a second package component, and dispensing an underfill between the first package component and the second package component. The underfill is in contact with the protection layer.

Provided is a semiconductor package including a first bump pad on a first substrate, a second bump pad on a second substrate, a core material for reverse reflow between the first bump pad and the second bump pad, and a solder member forming a solder layer on the core material for reverse reflow. The solder member is in contact with the first bump pad and the second bump pad. Each of a first diameter of the first bump pad and a second diameter of the second bump pad is at least about 1.1 times greater than a third diameter of the core material for reverse reflow. The core material for reverse reflow includes a core, a first metal layer directly coated on the core, and a second metal layer directly coated on the first metal layer.

Provided is a semiconductor package including a first bump pad on a first substrate, a second bump pad on a second substrate, a core material for reverse reflow between the first bump pad and the second bump pad, and a solder member forming a solder layer on the core material for reverse reflow. The solder member is in contact with the first bump pad and the second bump pad. Each of a first diameter of the first bump pad and a second diameter of the second bump pad is at least about 1.1 times greater than a third diameter of the core material for reverse reflow. The core material for reverse reflow includes a core, a first metal layer directly coated on the core, and a second metal layer directly coated on the first metal layer.

A three dimensional multi-die package includes a first die and second die. The first die includes a contact attached to solder. The second die is thinned by adhesively attaching a handler to a top side of the second die and thinning a bottom side of the second die. The second die includes a multilayer contact of layered metallurgy that inhibits transfer of adhesive thereto. The layered metallurgy includes at least one layer that is wettable to the solder. The multilayer contact may include a Nickel layer, a Copper layer upon the Nickel layer, and a Nickel-Iron layer upon the Copper layer. The multilayer contact may also include a Nickel layer, a Copper-Tin layer upon the Nickel layer, and a Tin layer upon the Copper-Tin layer.

A three dimensional multi-die package includes a first die and second die. The first die includes a contact attached to solder. The second die is thinned by adhesively attaching a handler to a top side of the second die and thinning a bottom side of the second die. The second die includes a multilayer contact of layered metallurgy that inhibits transfer of adhesive thereto. The layered metallurgy includes at least one layer that is wettable to the solder. The multilayer contact may include a Nickel layer, a Copper layer upon the Nickel layer, and a Nickel-Iron layer upon the Copper layer. The multilayer contact may also include a Nickel layer, a Copper-Tin layer upon the Nickel layer, and a Tin layer upon the Copper-Tin layer.

A semiconductor device has a conductive via in a first surface of a substrate. A first interconnect structure is formed over the first surface of the substrate. A first bump is formed over the first interconnect structure. The first bump is formed over or offset from the conductive via. An encapsulant is deposited over the first bump and first interconnect structure. A portion of the encapsulant is removed to expose the first bump. A portion of a second surface of the substrate is removed to expose the conductive via. The encapsulant provides structural support and eliminates the need for a separate carrier wafer when thinning the substrate. A second interconnect structure is formed over the second surface of the substrate. A second bump is formed over the first bump. A plurality of semiconductor devices can be stacked and electrically connected through the conductive via.

A semiconductor device has a conductive via in a first surface of a substrate. A first interconnect structure is formed over the first surface of the substrate. A first bump is formed over the first interconnect structure. The first bump is formed over or offset from the conductive via. An encapsulant is deposited over the first bump and first interconnect structure. A portion of the encapsulant is removed to expose the first bump. A portion of a second surface of the substrate is removed to expose the conductive via. The encapsulant provides structural support and eliminates the need for a separate carrier wafer when thinning the substrate. A second interconnect structure is formed over the second surface of the substrate. A second bump is formed over the first bump. A plurality of semiconductor devices can be stacked and electrically connected through the conductive via.

A semiconductor device has a substrate. A plurality of conductive vias is formed through the substrate. A conductive layer is formed over the substrate. An insulating layer is formed over conductive layer. A portion of the substrate is removed to expose the conductive vias. A plurality of vertical interconnect structures is formed over the substrate. A first semiconductor die is disposed over the substrate. A height of the vertical interconnect structures is less than a height of the first semiconductor die. An encapsulant is deposited over the first semiconductor die and the vertical interconnect structures. A first portion of the encapsulant is removed from over the first semiconductor die while leaving a second portion of the encapsulant over the vertical interconnect structures. The second portion of the encapsulant is removed to expose the vertical interconnect structures. A second semiconductor die is disposed over the first semiconductor die.

A semiconductor device has a substrate. A plurality of conductive vias is formed through the substrate. A conductive layer is formed over the substrate. An insulating layer is formed over conductive layer. A portion of the substrate is removed to expose the conductive vias. A plurality of vertical interconnect structures is formed over the substrate. A first semiconductor die is disposed over the substrate. A height of the vertical interconnect structures is less than a height of the first semiconductor die. An encapsulant is deposited over the first semiconductor die and the vertical interconnect structures. A first portion of the encapsulant is removed from over the first semiconductor die while leaving a second portion of the encapsulant over the vertical interconnect structures. The second portion of the encapsulant is removed to expose the vertical interconnect structures. A second semiconductor die is disposed over the first semiconductor die.

A tin plating solution and a method for fabricating a semiconductor device are provided. The tin plating solution comprises tin ions supplied from a soluble tin electrode, an aliphatic sulfonic acid having a carbon number of 1 to 10, an anti-oxidant, a wetting agent, and a grain refiner that is an aromatic carbonyl compound.