Conductive connections, structures with such connections, and methods of manufacture
In some embodiments, to increase the height-to-pitch ratio of a solder connection that connects different structures with one or more solder balls, only a portion of a solder ball's surface is melted when the connection is formed on one structure and/or when the connection is being attached to another structure. In some embodiments, non-solder balls are joined by an intermediate solder ball ( 140 i ). A solder connection may be surrounded by a solder locking layer ( 1210 ) and may be recessed in a hole ( 1230 ) in that layer. Other features are also provided.
1. A method for attaching a first conductive component to a second conductive component, the method comprising:
(1) melting a first portion of a surface of the first conductive component without melting a second portion of the surface of the first conductive component even though the second portion's melting temperature is no higher than the first portion's melting temperature, wherein the second portion is continuous with the first portion;
(2) bringing the melted first portion into physical contact with the second conductive component and cooling the first portion to form a conductive attachment between the first and second conductive components;
wherein the second portion is not melted in operations (1) and (2); and
wherein the first conductive component comprises a core having a higher melting temperature than the first portion of the surface of the first conductive component.
2. The method of claim 1 wherein in operation (2), the melted first portion is brought into physical contact with the second conductive component when the second conductive component is unmelted.
3. The method of claim 1 wherein a maximum pre-melted dimension of the first portion does not exceed 700 μm.
4. The method of claim 1 wherein the first portion is melted to a depth not exceeding 500 μm.
5. The method of claim 1 wherein the pre-melted volume of a melted portion of the first conductive component does not exceed 50% of the first conductive component.
6. The method of claim 1 wherein the second conductive component is a contact pad of a semiconductor integrated circuit or of a substrate attachable to a semiconductor integrated circuit, or the second conductive component is a connection component that has been attached to such contact pad before operation (1).
7. The method of claim 1 wherein the melting is performed by a beam of electromagnetic radiation.
8. A method for fabricating an electrical connection, the method comprising:
providing a first structure which comprises a first contact pad;
forming a first portion of the electrical connection on the first contact pad, the first portion comprising a first component comprising a first surface;
providing a second component of the electrical connection, the second component comprising a second surface comprising solder;
providing a third component of the electrical connection, the third component comprising a third surface;
attaching the second component to the first and third surfaces, wherein said attaching comprises melting the solder to obtain melted solder in physical contact with the first and third surfaces, and re-solidifying the solder to attach the solder to the first and third surfaces, wherein at least one of the first and third surfaces has an unmelted area which is not melted in said attaching even though a melting temperature of the unmelted area is not higher than a highest temperature of the solder in said attaching.
9. The method of claim 8 wherein the first and third surfaces are not melted in said attaching.
10. The method of claim 8 wherein at least one of the first and third surfaces has the same melting temperature as the solder.
11. The method of claim 8 wherein the third component is a solder ball which has the same melting temperature as the second component's solder but which is not melted in said attaching.
12. The method of claim 8 wherein the first structure comprises at least one of a semiconductor integrated circuit or a substrate attachable to a semiconductor integrated circuit.
13. The method of claim 8 wherein the melting is performed by a beam of electromagnetic radiation.
14. The method of claim 8 wherein the solder surrounds a core that does not melt in said attaching.
15. The method of claim 8 wherein the melting is performed only once during said attaching.
16. The method of claim 1 wherein the first conductive component does not physically contact the second conductive component during operation (1).
17. The method of claim 1 wherein the entire surface of the first component is the same material.
18. The method of claim 7 wherein the beam of electromagnetic radiation arrives at the first portion without first passing through the second portion.
19. The method of claim 7 wherein the beam of electromagnetic radiation arrives at the first portion without first passing through the first conductive component.
20. The method of claim 8 wherein the unmelted area physically contacts the melted solder in said attaching.