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 manufacturing method comprising:
obtaining a first structure comprising:
one or more first components each of which comprises solder and a material sublimatable or vaporizable when the solder is melted; and
a first layer comprising a top surface and one or more holes in the top surface, each hole containing at least a segment of a corresponding first component;
heating each first component to sublimate or vaporize at least part of each sublimatable or vaporizable material and provide an electrically conductive connection at a location of each first component;
wherein in the heating operation at least part of each first component recedes down from the top surface to provide or increase a recess in each hole at the top surface.
2. The method of claim 1 wherein each hole is a through-hole.
3. The method of claim 1 wherein each hole's sidewall is a dielectric sidewall.
4. The method of claim 1 wherein the first layer is dielectric.
5. The method of claim 1 wherein the first layer is formed by molding.
6. The method of claim 1 further comprising:
obtaining a second structure with one or more protruding conductive posts; and
inserting each conductive post into a corresponding recess provided or increased in the heating operation, and forming a solder bond in each recess between the corresponding conductive post and the corresponding electrically conductive connection.
7. The method of claim 1 wherein before the heating operation, at least a segment of each first component either:
comprises a solder core coated with the sublimatable or vaporizable material; or
consists of the sublimatable or vaporizable material.
8. The method of claim 7 wherein in obtaining the first structure, the one or more first components are formed before the first layer.
9. The method of claim 1 wherein in obtaining the first structure, the one or more first components are formed after the first layer, and forming the one or more first components comprises depositing the solder and the sublimatable or vaporizable material into each hole.
10. The method of claim 9 wherein depositing the solder and the sublimatable or vaporizable material into each hole comprises:
(a) depositing a portion of the solder and a portion of the sublimatable or vaporizable material into each hole; then
(b) heating the solder and the sublimatable or vaporizable material in each hole to sublimate or vaporize at least some of the sublimatable or vaporizable material in each hole and to cause the remaining solder to recede down and provide or increase a recess in each hole; and then
(c) depositing additional solder and additional sublimatable or vaporizable material into at least one hole.
11. The method of claim 10 wherein the operation (c) comprises repeating the operations (a) and (b) one or more times.
12. The method of claim 10 wherein in the operation (c), the additional solder and the additional sublimatable or vaporizable material are deposited into less than all holes.
13. The method of claim 12 wherein the method results in recesses of different depths in at least two different holes.
14. The method of claim 10 wherein:
operation (a) comprises depositing, into each hole, a first material comprising said portion of the solder;
operation (c) comprises depositing, into at least one hole, a second material comprising said additional solder; and
the first material has a different composition than the second material.
15. The method of claim 14 wherein at at least one temperature at which both the first and second materials are not solid, the first material is less viscous than the second material.
16. The method of claim 14 wherein at at least one temperature, the second material is less oxidizable than the first material.
17. The method of claim 14 wherein the second material provides a better barrier to contamination or corrosion than the first material.
18. The method of claim 14 wherein the second material has at least one element of a group consisting of copper, silver, gold, and nickel, and the first material does not have said element or has a lower concentration of said element than the first material.
19. The method of claim 14 wherein the first material has a smaller percentage of the sublimatable or vaporizable material than does the second material.
20. The method of claim 1 wherein the first structure comprises an integrated circuit.
21. The method of claim 1 wherein in a top view, at least a segment of each electrically conductive connection is completely laterally surrounded by the first layer.
22. The method of claim 1 wherein at the solder's melting temperature, the sublimatable or vaporizable material has a lower density than the solder.