Method for building interconnect structures by injection molded solder and structures built

Patent 5775569 Issued on July 7, 1998. Estimated Expiration Date:

October 31, 2016. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

Methods and apparatus for soldering without using flux
Patent #: 5193738
Issued on: 03/16/1993
Inventor: Hayes

Apparatus and method for injection molding solder and applications thereof
Patent #: 5244143
Issued on: 09/14/1993
Inventor: Ference, et al.

Surface mount solder assembly of leadless integrated circuit packages to substrates Patent #: 5346118
Issued on: 09/13/1994
Inventor: Degani, et al.

Inventors

Assignee

IBM Corporation

Application

No. 741453 filed on 10/31/1996

US Classes:

228/254, Adherent solid layer or coating (e.g., pretinned)228/56.3, SOLDER FORM257/E21.508, Forming solder bumps (EPO)438/613, Bump electrode438/614Plural conductive layers

Examiners

Primary: Heinrich, Samuel M.

Attorney, Agent or Firm

Tung & Associates

International Class

H05K 003/34

Abstract

A method for forming solder bumps on an electronic structure including the steps of first providing a mold made by a sheet of a mold material having a thickness greater than that of the solder bumps to be formed, the mold material has sufficient optical transparency so as to allow the inspection of a solder material subsequently filled into the mold cavities that are formed in the mold material, and a coefficient of thermal expansion that is substantially similar to the substrate which the mold will be mated to, forming a multiplicity of mold cavities in the sheet of mold material, filling the multiplicity of mold cavities with a solder material, cooling the mold to a temperature that is sufficient to solidify the solder material in the multiplicity of mold cavities, positioning the mold intimately with the electronic structure such that the cavities facing the structure, and heating the mold and the structure together to a temperature sufficiently high such that the solder material transfers onto the electronic structure.