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 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.

An electroplating method that is a conventional method has had a problem that it is difficult to manufacture fine pillars without being affected by an undercut. Furthermore, an electroless plating method has had a problem that it is difficult to manufacture pillars having the same shape without any void. The inventors have performed intensive investigations to solve the above problems and, as a result, have found that fine conductive pillars with a high aspect ratio can be readily manufactured on a substrate having an electrode section in such a manner that after a conductive paste containing metal micro-particles is applied in a reduced pressure state, the conductive paste is exposed to standard pressure. The present invention has a particular effect on the manufacture of a metal pillar that is a terminal for flip-chip mounting.

An electroplating method that is a conventional method has had a problem that it is difficult to manufacture fine pillars without being affected by an undercut. Furthermore, an electroless plating method has had a problem that it is difficult to manufacture pillars having the same shape without any void. The inventors have performed intensive investigations to solve the above problems and, as a result, have found that fine conductive pillars with a high aspect ratio can be readily manufactured on a substrate having an electrode section in such a manner that after a conductive paste containing metal micro-particles is applied in a reduced pressure state, the conductive paste is exposed to standard pressure. The present invention has a particular effect on the manufacture of a metal pillar that is a terminal for flip-chip mounting.

The known electrolytic plating method is disadvantageous in that it is difficult to form thin pillars without being influenced by undercuts. The electroless plating method is disadvantageous in that it is difficult to form pillars in the same shape without voids. As a solution to these, the electrically conductive paste according to the present invention for forming pillars is used to make pillars by filling. This helps prevent undercuts, and it is also intended to provide metal pillars in the same shape with good reproducibility. The inventors found that an electrically conductive paste that is very small fine metal particles and contains a particular percentage of fine metal particles is extraordinarily advantageous in forming pillars.

The known electrolytic plating method is disadvantageous in that it is difficult to form thin pillars without being influenced by undercuts. The electroless plating method is disadvantageous in that it is difficult to form pillars in the same shape without voids. As a solution to these, the electrically conductive paste according to the present invention for forming pillars is used to make pillars by filling. This helps prevent undercuts, and it is also intended to provide metal pillars in the same shape with good reproducibility. The inventors found that an electrically conductive paste that is very small fine metal particles and contains a particular percentage of fine metal particles is extraordinarily advantageous in forming pillars.