A method includes providing a first and a second joining partner each having a first main surface, wherein at least a portion of the first main surfaces of the first and joining partners each comprise a metal layer. The method further includes applying a plurality of solder preforms to the metal layer of the first main surface of at least one of the first and second joining partners, positioning the first and second joining partners so that the solder preforms contact the metal layers of the first main surfaces of the first and second joining partners, and melting the plurality of solder preforms under pressure to form a single continuous thin layer area interconnect comprising a diffusion solder bond which bonds together the metal layers of the of the first main surfaces of the first and second joining partners.

A semiconductor device has a semiconductor die having a plurality of die bump pad and substrate having a plurality of conductive trace with an interconnect site. A solder mask patch is formed interstitially between the die bump pads or interconnect sites. A conductive bump material is deposited on the interconnect sites or die bump pads. The semiconductor die is mounted to the substrate so that the conductive bump material is disposed between the die bump pads and interconnect sites. The conductive bump material is reflowed without a solder mask around the die bump pad or interconnect site to form an interconnect structure between the semiconductor die and substrate. The solder mask patch confines the conductive bump material within the die bump pad or interconnect site. The interconnect structure can include a fusible portion and non-fusible portion. An encapsulant is deposited between the semiconductor die and substrate.

Provided is a method of fabricating a semiconductor package. The method includes providing a package substrate including a pad, mounting a semiconductor chip with a solder ball on the package substrate to allow the solder ball to be disposed on the pad, filling a space between the package substrate and the semiconductor chip with a underfill resin including a reducing agent comprising a carboxyl group, and irradiating the semiconductor chip with a laser to bond the solder ball to the pad, wherein the bonding of the solder ball to the pad comprises changing a metal oxide layer formed on surfaces of the pad and the solder ball to a metal layer by heat generated by the laser.

Methods and structures of connecting at least two integrated circuits in a 3D arrangement by a zigzag conductive chain are disclosed. The zigzag conductive chain, acting as a spring or self-adaptive contact structure (SACS) in a wafer bonding process, is designed to reduce bonding interface stress, to increase bonding interface reliability, and to have an adjustable height to close undesirable opens or voids between contacts of the two integrated circuits.

Laser assisted bonding for semiconductor die interconnections is disclosed and may, for example, include forming flux on a circuit pattern on a circuit board, placing a semiconductor die on the circuit board where a bump on the semiconductor die contacts the flux, and reflowing the bump by directing a laser beam toward the semiconductor die. The laser beam may volatize the flux and make an electrical connection between the bump and the circuit pattern. A jig plate may be placed on the semiconductor die when the laser beam is directed toward the semiconductor die. Warpage may be reduced during heating or cooling of the semiconductor die by applying pressure to the jig plate. Jig bars may extend outward from the jig plate and may be in contact with the circuit board during the application of pressure to the jig plate. The jig plate may comprise one or more of: silicon, silicon carbide, and glass.

Methods and structures of connecting at least two integrated circuits in a 3D arrangement by a zigzag conductive chain are disclosed. The zigzag conductive chain, acting as a spring or self-adaptive contact structure (SACS) in a wafer bonding process, is designed to reduce bonding interface stress, to increase bonding interface reliability, and to have an adjustable height to close undesirable opens or voids between contacts of the two integrated circuits.