Semiconductor device manufacturing: process – Coating with electrically or thermally conductive material – To form ohmic contact to semiconductive material
Reexamination Certificate
1998-02-25
2001-08-07
Whitehead, Jr., Carl (Department: 2822)
Semiconductor device manufacturing: process
Coating with electrically or thermally conductive material
To form ohmic contact to semiconductive material
C438S597000, C438S615000
Reexamination Certificate
active
06271111
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to a high density pluggable connector array and process thereof. More particularly, the invention encompasses a structure comprising high density pluggable connector arrays. A process for making such types of high density pluggable connector arrays is also disclosed.
BACKGROUND OF THE INVENTION
Semiconductor devices are becoming smaller and more dense with the evolution of new technology. In order to remain competitive chip manufacturers are therefore constantly challenged to improve their products. Significant improvements, such as, reducing process variability, have being made. However, process improvements alone are not sufficient. The inventors have therefore invented a new high density pluggable connector array and a process, and are thus making a contribution to this growing and challenging field.
The prior art has also tried to contribute to this emerging field, for example, U.S. Pat. No. 4,693,770 (Hatada), discloses a method of bonding semiconductor devices together. A metal bump is formed on a substrate, which is transferred and joined onto the electrode of a first semiconductor device, and this first semiconductor device is joined to a second semiconductor device by pressing and heating such that the electrode of the second device and the transferred metal bump are in electrical and physical contact.
U.S. Pat. No. 5,134,460 (Brady), discloses an aluminum bump, a reworkable bump, and titanium nitride structure for tab bonding. On a semiconductor substrate, having a passivation layer, a bump is over an adhesion layer. The bump, made from aluminum, has a coating of a first metallic layer, such as, for example, Ti or Cr, a second metallic layer, such as, for example, Co or Ni, and a metallic layer, such as, for example, Au. The substrate with the bump is subsequently joined to a copper body.
However, the inventors of this invention have discovered a new way of providing a high density pluggable connector array, with the benefit of providing an exposed electrical connection that is resilient to the environment and that has a strong electrical bond to the ceramic or organic substrate.
PURPOSES AND SUMMARY OF THE INVENTION
The invention is a novel method and structure for high density pluggable connector array.
Therefore, one purpose of this invention is to provide an apparatus and a method that will provide a high density pluggable connector array.
Another purpose of this invention is to provide for an electrical interconnection on a ceramic or organic substrate that has a very strong bond and is very economical to manufacture.
Still another purpose of this invention is to have a connector array with a multi-level of metal protection to the electrical interconnect.
Yet another purpose of this invention is to allow the use of low melting solders to join the connecting features, while providing highly reliable gold surface for making electrical contact.
Therefore, in one aspect this invention comprises a high density connector array comprising a substrate having at least one reflowed solder connection connecting an interconnect element to a pad on said substrate, wherein said interconnect element has at least one layer of gold completely enveloping at least one layer of nickel and wherein said layer of nickel completely envelopes a core, and thereby provides said high density connector array.
In another aspect this invention comprises a multi-layered, interconnect structure comprising at least one layer of copper completely enveloping at least one layer of gold, wherein said layer of gold completely envelopes at least one layer of nickel, and wherein said layer of nickel completely envelopes a core, and thereby providing said multi-layered interconnect structure.
In yet another aspect this invention comprises a multi-layered interconnect structure comprising at least one layer of copper completely enveloping at least one layer of cobalt, wherein said layer of cobalt completely envelopes at least one layer of gold, wherein said layer of gold completely envelopes at least one layer of nickel, and wherein said layer of nickel completely envelopes a core, and thereby providing said multi-layered interconnect structure.
In still another aspect this invention comprises a process for forming a multi-layered interconnect structure comprising the steps of:
(a) depositing at least one layer of nickel on a core and completely enveloping said core,
(b) depositing at least one layer of gold over said layer of nickel and completely enveloping said layer of nickel,
(c) depositing at least one layer of copper over said layer of gold and completely enveloping said layer of gold, and thereby providing said multi-layered interconnect structure.
In still yet another aspect this invention comprises a process of making high density connector array comprising the steps of:
(a) placing at least one multi-layered interconnect structure on a boat having at least one means to accommodate at least a portion of said interconnect structure,
(b) forming a sub-assembly by placing said multi-layered interconnect in said boat in intimate contact with a solder connection on a semiconductor substrate,
(c) subjecting said solder connection to reflow conditions such that said solder reflows and joins said multi-layered interconnect structure, and thereby forms said high density connector array.
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Farooq Shaji
Kaja Suryanarayana
Wang Li
Abate Joseph P.
Ahsan Aziz M.
International Business Machines - Corporation
Jr. Carl Whitehead
Vockrodt Jeff
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