Connector formation methods and packaged semiconductor devices

A semiconductor structure comprising:

• a first conductive feature and a second conductive feature;
• an insulating material over the first conductive feature and the second conductive feature, the insulating material having a first opening extending from the first conductive feature to an upper surface of the insulating material, the first opening of the insulating material having a first width, the insulating material further having a second opening extending from the second conductive feature to the upper surface of the insulating material, the second opening of the insulating material having a second width;
• a first connector extending through the first opening to the first conductive feature, the first connector having a third width measured between first outer straight sidewalls of the first connector, the third width of the first connector being less than the first width of the first opening, bottom points of the first outer straight sidewalls of the first connector physically contacting the first conductive feature, the first connector comprising a first metal layer and a second metal layer on the first metal layer, the second metal layer being a different material from the first metal layer, wherein a top surface of the first metal layer is above a bottom surface of the first opening, a bottom surface of the second metal layer is below a top surface of the insulating material, and a top surface of the second metal layer is above the top surface of the insulating material and a third metal layer on the second metal layer, wherein the first metal layer and the second metal layer each comprise a thickness of less than 10 μm of Cu, wherein the third metal layer comprises a thickness of 3 μm to 50 μm of a lead-free solder;
• and
• a second connector extending through the second opening in the insulating material to the second conductive feature.

A semiconductor structure comprising:

• an interconnect structure comprising an insulating material and a plurality of conductive features, wherein a portion of the insulating material is in direct contact with a top surface of a top conductive feature of the plurality of conductive features;
• and
• a connector disposed on the interconnect structure, the connector directly on and extending through the portion of the insulating material that is in direct contact with the top surface of the top conductive feature, the connector comprising a first portion having a first width proximate to the interconnect structure and having a top surface that is above the portion of the insulating material that is in direct contact with the top surface of the top conductive feature, a second portion having a second width coupled to the first portion, wherein the second portion comprises an upper-most surface width substantially equal to the second width and a lower-most surface width substantially equal to the second width, wherein the second width is less than the first width, and a third portion having a third width coupled to the first portion, wherein the third portion is directly coupled to the top surface of the top conductive feature, the first portion and the third portion of the connector being provided by a first metal layer having a different composition from one or more second metal layers that provide the second portion of the connector, the first portion of the connector having a substantially flat surface at an interface of the first portion and the second portion, wherein sidewalls of the third portion directly contact sidewalls of the insulating material, wherein the third portion has a height in a range of 5 μm to 50 μm, and wherein the third width is between 5 μm to 10 μm smaller than the first width, and wherein the first width is between 2 μm to 10 μm larger than the second width.