The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 16, 1991
Filed:
Sep. 08, 1989
Phillip J Spletter, Cedar Park, TX (US);
Colin A MacKay, Austin, TX (US);
Microelectronics and Computer Technology Corporation, Austin, TX (US);
Abstract
A method is disclosed for laser bonding two highly reflective electrical members. The first electrical member is coated with a material that is well absorbent of laser energy at the laser beam wavelength, has a lower melting point than either the first or second electrical members, and has a low solubility in a solid alloy of the electrical members. The laser characteristics are selected so that as bonding occurs an alloy of the electrical members solidifies and a solidification front drives the molten coating and molten compounds containing the coating away from the bond interface towards the exterior periphery of the bond, and substantially all of the solidified bond interface consists of an alloy of the first and second members. The coating can also aid in wetting the bond interface. In one example a copper electrical member coated with tin is bonded to a gold electrical member using a pulsed YAG laser with a beam diameter of 0.002 inches, a wavelength of 1.064 microns, an energy output of 1/4 to 1/2 joule, and a pulse time of 1 millisecond. Substantially all of the resulting bond interface consists of a copper/gold alloy without any tin intermetallics.