Conductive connections, structures with such connections, and methods of manufacture
A solder connection may be surrounded by a solder locking layer ( 1210, 2210 ) and may be recessed in a hole ( 1230 ) in that layer. The recess may be obtained by evaporating a vaporizable portion ( 1250 ) of the solder connection. Other features are also provided.
1. A manufacture comprising:
a first structure comprising one or more contact pads;
one or more electrically conductive connections each of which has a bottom attached to at least one contact pad and comprises solder; and
a first layer comprising a top surface and one or more through-holes in the top surface, each through-hole's sidewall being a dielectric sidewall, each through-hole containing at least a segment of a corresponding electrically conductive connection, the segment physically contacting the through-hole's dielectric sidewall, the electrically conductive connection being recessed in the through-hole at the top of the through-hole;
wherein the first layer comprises:
a first dielectric sub-layer comprising, at each electrically conductive connection, an upward protrusion protruding above the first structure and laterally surrounding and physically contacting the electrically conductive connection; and
a second dielectric sub-layer overlaying the first dielectric sub-layer, the second dielectric sub-layer laterally surrounding each upward protrusion, the second dielectric sub-layer being a different material than the first dielectric sub-layer;
wherein each electrically conductive connection physically contacts the first dielectric sub-layer but not the second dielectric sub-layer; and
each electrically conductive connection and the first dielectric sub-layer are recessed in each through-hole.
2. The manufacture of claim 1 wherein at least one through-hole's sidewall has a concave portion at the top of the through-hole, the concave portion being a portion of a sidewall of the first dielectric sub-layer.
3. The manufacture of claim 1 wherein at least one through-hole's sidewall has a concave portion below the top of the through-hole and has a convex portion immediately above the concave portion.
4. The manufacture of claim 1 wherein in at least one plane cross-section extending along at least one through-hole, the through-hole's sidewall is a straight line on each side of the through-hole.
5. The manufacture of claim 1 wherein at least one electrically conductive connection is attached to a non-solder conductive post of a second structure, the conductive post being partially located in a top portion of the corresponding through-hole.
6. The manufacture of claim 1 wherein each electrically conductive connection consists essentially of solder.
7. The manufacture of claim 1 wherein the first sub-layer is inorganic dielectric.
8. The manufacture of claim 1 wherein the one or more electrically conductive connections are a plurality of the electrically conductive connections, wherein at least two of the electrically conductive connections have different lengths.
9. The manufacture of claim 1 wherein the one or more electrically conductive connections are a plurality of the electrically conductive connections, wherein at least two of the electrically conductive connections have different heights in a view in which the electrically conductive connections are attached to one or more contact pads located at the same height.
10. The manufacture of claim 9 wherein the height-to-pitch ratio of the at least two of the electrically conductive connections is greater than 1.5.
11. The manufacture of claim 9 wherein the height-to-pitch ratio of the at least two of the electrically conductive connections is greater than 2.