A heating method includes an oxide film forming step and a heating step. The thickness of an oxide film is set in a first range that includes a first maximal thickness and a second maximal thickness and that is smaller than a second minimal thickness in the relationship with the laser absorption having a periodic profile. The first maximal thickness corresponds to a first maximal value a of the laser absorption. The second maximal thickness corresponds to a second maximal value of the laser absorption. The second minimal thickness corresponds to a second minimal value of the laser absorption, namely the minimal value of the laser absorption that appears between the second maximal value and a third maximal value, or the maximal value of the laser absorption that appears subsequent to the second maximal value.

An interposer may comprise a metal layer above a substrate. A dam or a plurality of dams may be formed above the metal layer. A dam surrounds an area of a size larger than a size of a die which may be connected to a contact pad above the metal layer within the area. A dam may comprise a conductive material, or a non-conductive material, or both. An underfill may be formed under the die, above the metal layer, and contained within the area surrounded by the dam, so that no underfill may overflow outside the area surrounded by the dam. Additional package may be placed above the die connected to the interposer to form a package-on-package structure.

In an aspect, an integrated circuit (IC) package includes a base structure, an IC component disposed on the base structure, a plurality of interposer connection structures disposed on the base structure, and an interposer structure disposed over the IC component and the plurality of interposer connection structures. The plurality of interposer connection structures is configured to connect the base structure and the interposer structure. Each interposer connection structure of the plurality of interposer connection structures includes a bond ball portion that is connected to the base structure, and a bond wire portion that is coupled to the bond ball portion and extends toward the interposer structure. A width of the bond ball portion is greater than a width of the bond wire portion.

A semiconductor package is fabricated by attaching a first component to a second component. The first component is assembled by forming a first redistribution structure over a substrate. A through via is then formed over the first redistribution structure, and a die is attached to the first redistribution structure active-side down. The second component includes a second redistribution structure, which is then attached to the through via. A molding compound is deposited between the first redistribution structure and the second redistribution structure and further around the sides of the second component.

An interposer may comprise a metal layer above a substrate. A dam or a plurality of dams may be formed above the metal layer. A dam surrounds an area of a size larger than a size of a die which may be connected to a contact pad above the metal layer within the area. A dam may comprise a conductive material, or a non-conductive material, or both. An underfill may be formed under the die, above the metal layer, and contained within the area surrounded by the dam, so that no underfill may overflow outside the area surrounded by the dam. Additional package may be placed above the die connected to the interposer to form a package-on-package structure.

A semiconductor package is fabricated by attaching a first component to a second component. The first component is assembled by forming a first redistribution structure over a substrate. A through via is then formed over the first redistribution structure, and a die is attached to the first redistribution structure active-side down. The second component includes a second redistribution structure, which is then attached to the through via. A molding compound is deposited between the first redistribution structure and the second redistribution structure and further around the sides of the second component.