A printed electrical connection structure includes a substrate having one or more electrical connection pads and a micro-transfer printed component having one or more connection posts. Each connection post is in electrical contact with a connection pad. A resin is disposed between and in contact with the substrate and the component. The resin has a reflow temperature less than a cure temperature. The resin repeatedly flows at the reflow temperature when temperature-cycled between an operating temperature and the reflow temperature but does not flow after the resin is exposed to a cure temperature. A solder can be disposed on the connection post or the connection pad. After printing and reflow, the component can be tested and, if the component fails, another component is micro-transfer printed to the substrate, the resin is reflowed again, the other component is tested and, if it passes the test, the resin is finally cured.

A solder ball includes a silver ball structure and a shell structure. The shell structure wraps a surface of the silver ball structure, and a material of the shell structure at least includes tin. When the solder ball is bonded to other devices, the ball height of the solder ball remains constant to avoid collapse.

A solder ball includes a silver ball structure and a shell structure. The shell structure wraps a surface of the silver ball structure, and a material of the shell structure at least includes tin. When the solder ball is bonded to other devices, the ball height of the solder ball remains constant to avoid collapse.

The embodiments described above provide enlarged overlapping surface areas of bonding structures between a package and a bonding substrate. By using elongated bonding structures on either the package and/or the bonding substrate and by orienting such bonding structures, the bonding structures are designed to withstand bonding stress caused by thermal cycling to reduce cold joints.

The embodiments described above provide enlarged overlapping surface areas of bonding structures between a package and a bonding substrate. By using elongated bonding structures on either the package and/or the bonding substrate and by orienting such bonding structures, the bonding structures are designed to withstand bonding stress caused by thermal cycling to reduce cold joints.

A semiconductor package includes a first chip, an insulating protection layer, a second chip, a plurality of second conductive bumps and an underfill. The insulating protection layer is disposed on a first active surface of the first chip and includes a concave. Projections of a plurality of first inner pads and a plurality of first outer pads of the first chip projected on the insulating protection layer are located in the concave and out of the concave, respectively. The second chip is flipped on the concave and includes a plurality of second pads. Each of the first inner pads is electrically connected to the corresponding second pad through the corresponding second conductive bump. The underfill is disposed between the concave and the second chip and covers the second conductive bumps.

A semiconductor package includes a first chip, an insulating protection layer, a second chip, a plurality of second conductive bumps and an underfill. The insulating protection layer is disposed on a first active surface of the first chip and includes a concave. Projections of a plurality of first inner pads and a plurality of first outer pads of the first chip projected on the insulating protection layer are located in the concave and out of the concave, respectively. The second chip is flipped on the concave and includes a plurality of second pads. Each of the first inner pads is electrically connected to the corresponding second pad through the corresponding second conductive bump. The underfill is disposed between the concave and the second chip and covers the second conductive bumps.

A method of fabricating a connection structure is disclosed. The method includes providing a substrate that has a top surface and includes a set of pads for soldering, each of which has a pad surface exposed from the top surface of the substrate. The method also includes applying a surface treatment to a part of the top surface of the substrate close to the pads and the pad surface of each pad so as to make at least the part of the top surface and the pad surfaces of the pads rougher. The surface treatment includes sandblasting.

A method of fabricating a connection structure is disclosed. The method includes providing a substrate that has a top surface and includes a set of pads for soldering, each of which has a pad surface exposed from the top surface of the substrate. The method also includes applying a surface treatment to a part of the top surface of the substrate close to the pads and the pad surface of each pad so as to make at least the part of the top surface and the pad surfaces of the pads rougher. The surface treatment includes sandblasting.

A semiconductor device has a first conductive layer including a plurality of conductive traces. The first conductive layer is formed over a substrate. The conductive traces are formed with a narrow pitch. A first semiconductor die and second semiconductor die are disposed over the first conductive layer. A first encapsulant is deposited over the first and second semiconductor die. The substrate is removed. A second encapsulant is deposited over the first encapsulant. A build-up interconnect structure is formed over the first conductive layer and second encapsulant. The build-up interconnect structure includes a second conductive layer. A first passive device is disposed in the first encapsulant. A second passive device is disposed in the second encapsulant. A vertical interconnect unit is disposed in the second encapsulant. A third conductive layer is formed over second encapsulant and electrically connected to the build-up interconnect structure via the vertical interconnect unit.