A method includes aligning a first electrical connector of a first package component to a second electrical connector of a second package component. With the first electrical connector aligned to the second electrical connector, a metal layer is plated on the first and the second electrical connectors. The metal layer bonds the first electrical connector to the second electrical connector.

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 m, 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 microelectronic device has a pillar connected to an external terminal by an intermetallic joint. Either the pillar or the external terminal, or both, include copper in direct contact with the intermetallic joint. The intermetallic joint includes at least 90 weight percent of at least one copper-tin intermetallic compound. The intermetallic joint is free of voids having a combined volume greater than 10 percent of a volume of the intermetallic joint; and free of a void having a volume greater than 5 percent of the volume of the intermetallic joint. The microelectronic device may be formed using solder which includes at least 93 weight percent tin, 0.5 weight percent to 5.0 weight percent silver, and 0.4 weight percent to 1.0 weight percent copper, to form a solder joint between the pillar and the external terminal, followed by thermal aging to convert the solder joint to the intermetallic joint.

A microelectronic device has a pillar connected to an external terminal by an intermetallic joint. Either the pillar or the external terminal, or both, include copper in direct contact with the intermetallic joint. The intermetallic joint includes at least 90 weight percent of at least one copper-tin intermetallic compound. The intermetallic joint is free of voids having a combined volume greater than 10 percent of a volume of the intermetallic joint; and free of a void having a volume greater than 5 percent of the volume of the intermetallic joint. The microelectronic device may be formed using solder which includes at least 93 weight percent tin, 0.5 weight percent to 5.0 weight percent silver, and 0.4 weight percent to 1.0 weight percent copper, to form a solder joint between the pillar and the external terminal, followed by thermal aging to convert the solder joint to the intermetallic joint.

A microelectronic device has a bump bond structure including an electrically conductive pillar with an expanded head, and solder on the expanded head. The electrically conductive pillar includes a column extending from an I/O pad to the expanded head. The expanded head extends laterally past the column on at least one side of the electrically conductive pillar. In one aspect, the expanded head may have a rounded side profile with a radius approximately equal to a thickness of the expanded head, and a flat top surface. In another aspect, the expanded head may extend past the column by different lateral distances in different lateral directions. In a further aspect, the expanded head may have two connection areas for making electrical connections to two separate nodes. Methods for forming the microelectronic device are disclosed.

A microelectronic device has a bump bond structure including an electrically conductive pillar with an expanded head, and solder on the expanded head. The electrically conductive pillar includes a column extending from an I/O pad to the expanded head. The expanded head extends laterally past the column on at least one side of the electrically conductive pillar. In one aspect, the expanded head may have a rounded side profile with a radius approximately equal to a thickness of the expanded head, and a flat top surface. In another aspect, the expanded head may extend past the column by different lateral distances in different lateral directions. In a further aspect, the expanded head may have two connection areas for making electrical connections to two separate nodes. Methods for forming the microelectronic device are disclosed.

The Cu core ball contains a Cu ball and one or more metal layer for covering a surface of the Cu ball, each layer including one or more element selected from Ni, Co, Fe and Pd. The Cu ball contains at least one element selected from Fe, Ag, and Ni in a total amount of 5.0 or more to 50.0 ppm by mass or lower, S in an amount of 0 ppm by mass or more to 1.0 ppm by mass or lower, P in an amount of 0 ppm by mass or more to less than 3.0 ppm by mass, and remainder of Cu and inevitable impurities. The Cu ball contains purity which is 99.995% by mass or higher and 99.9995% or lower, sphericity which is 0.95 or higher and a diameter of 1 m or more to 1000 m or lower.

A microelectronic device has a bump bond structure including an electrically conductive pillar with an expanded head, and solder on the expanded head. The electrically conductive pillar includes a column extending from an I/O pad to the expanded head. The expanded head extends laterally past the column on at least one side of the electrically conductive pillar. In one aspect, the expanded head may have a rounded side profile with a radius approximately equal to a thickness of the expanded head, and a flat top surface. In another aspect, the expanded head may extend past the column by different lateral distances in different lateral directions. In a further aspect, the expanded head may have two connection areas for making electrical connections to two separate nodes. Methods for forming the microelectronic device are disclosed.

A microelectronic device has a bump bond structure including an electrically conductive pillar with an expanded head, and solder on the expanded head. The electrically conductive pillar includes a column extending from an I/O pad to the expanded head. The expanded head extends laterally past the column on at least one side of the electrically conductive pillar. In one aspect, the expanded head may have a rounded side profile with a radius approximately equal to a thickness of the expanded head, and a flat top surface. In another aspect, the expanded head may extend past the column by different lateral distances in different lateral directions. In a further aspect, the expanded head may have two connection areas for making electrical connections to two separate nodes. Methods for forming the microelectronic device are disclosed.

A microelectronic device has a pillar connected to an external terminal by an intermetallic joint. Either the pillar or the external terminal, or both, include copper in direct contact with the intermetallic joint. The intermetallic joint includes at least 90 weight percent of at least one copper-tin intermetallic compound. The intermetallic joint is free of voids having a combined volume greater than 10 percent of a volume of the intermetallic joint; and free of a void having a volume greater than 5 percent of the volume of the intermetallic joint. The microelectronic device may be formed using solder which includes at least 93 weight percent tin, 0.5 weight percent to 5.0 weight percent silver, and 0.4 weight percent to 1.0 weight percent copper, to form a solder joint between the pillar and the external terminal, followed by thermal aging to convert the solder joint to the intermetallic joint.