Provided are a Cu column, a Cu core column, a solder joint, and a through-silicon via, which have the low Vickers hardness and the small arithmetic mean roughness. For the Cu column 1 according to the present invention, its purity is equal to or higher than 99.9% and equal to or lower than 99.995%, its arithmetic mean roughness is equal to or less than 0.3 μm, and its Vickers hardness is equal to or higher than 20 HV and equal to or less than 60 HV. Since the Cu column 1 is not melted at a melting temperature in the soldering and a definite stand-off height (a space between the substrates) can be maintained, it is preferably applied to the three dimensional mounting or the pitch narrowing mounting.

A Cu core ball and a method of manufacturing such a Cu core ball. Purity of the Cu internal ball is at least 99.9% and not greater than 99.995%. A total contained amount of Pb and/or Bi in impurity contained in the Cu ball is equal to or larger than 1 ppm. Its sphericity is at least 0.95. A solder plating film coated on the Cu ball is of Sn solder or a lead free solder alloy whose primary component is Sn. In the solder plating film, a contained amount of U is not more than 5 ppb and that of Th is not more than 5 ppb. A total alpha dose of the Cu ball and the solder plating film is not more than 0./0200 cph/cm2. An arithmetic average roughness of the Cu core ball is equal to or less than 0.3 μm.

Provided are a lead-free solder alloy which consists of Sb in an amount of more than 3.0% but 10% or less by mass, and the balance including Sn, and others.

A semiconductor package of a pin-grid-array type includes a bump pad on a first substrate, a metal socket on a second substrate, a core material for reverse reflow on the bump pad, and solder paste or a solder bump forming a solder layer on the core material for reverse reflow. The solder paste or the solder bump is in contact with the bump pad. The core material for reverse reflow and the solder paste or the solder bump bonded to the core material for reverse reflow are used as a pin and detachably attached to the metal socket. 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 semiconductor package of a pin-grid-array type includes a bump pad on a first substrate, a metal socket on a second substrate, a core material for reverse reflow on the bump pad, and solder paste or a solder bump forming a solder layer on the core material for reverse reflow. The solder paste or the solder bump is in contact with the bump pad. The core material for reverse reflow and the solder paste or the solder bump bonded to the core material for reverse reflow are used as a pin and detachably attached to the metal socket. 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.

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 method for fabricating a semiconductor device with a heterogeneous solder joint includes: providing a semiconductor die; providing a coupled element; and soldering the semiconductor die to the coupled element with a first solder joint. The first solder joint includes: a solder material including a first metal composition; and a coating including a second metal composition, different from the first metal composition, the coating at least partially covering the solder material. The second metal composition has a greater stiffness and/or a higher melting point than the first metal composition.

A microelectronic device includes a die with input/output (I/O) terminals, and a dielectric layer on the die. The microelectronic device includes electrically conductive pillars which are electrically coupled to the I/O terminals, and extend through the dielectric layer to an exterior of the microelectronic device. Each pillar includes a column electrically coupled to one of the I/O terminals, and a head contacting the column at an opposite end of the column from the I/O terminal. The head extends laterally past the column in at least one lateral direction. Methods of forming the pillars and the dielectric layer are disclosed.

A microelectronic device includes a die with input/output (I/O) terminals, and a dielectric layer on the die. The microelectronic device includes electrically conductive pillars which are electrically coupled to the I/O terminals, and extend through the dielectric layer to an exterior of the microelectronic device. Each pillar includes a column electrically coupled to one of the I/O terminals, and a head contacting the column at an opposite end of the column from the I/O terminal. The head extends laterally past the column in at least one lateral direction. Methods of forming the pillars and the dielectric layer are disclosed.