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. 23, 2002
Filed:
Jul. 19, 2000
Robert Edward Silhavy, Redondo Beach, CA (US);
The Boeing Company, Seattle, WA (US);
Abstract
A chip bonding location of a microelectronic chip is joined to a substrate bonding location of a substrate using a metallic solder in the absence of a flux. Surface contamination and oxide are first removed from the chip bonding location and from the substrate bonding location. The joining is accomplished by positioning the microelectronic chip and the substrate in a facing contact with the chip bonding location and the substrate bonding location in registry in a contact region. A heating element is disposed adjacent to and below the chip bonding location and the substrate bonding location to form an assembly. There is no flux present in the assembly in the contact region. The assembly is placed into an oven having a non-oxidizing environment. The chip bonding location and the substrate bonding location are joined by heating the assembly to a preheating temperature of less than a melting temperature of the solder, and thereafter reflowing the solder by locally heating the contact region to a reflow temperature of greater than the melting temperature of the solder using the heating element, permitting the solder in the contact region to melt for a reflow period of time above the melting temperature of the solder, and then cooling the contact region to a temperature below the melting temperature of the solder. The solder is melted for a short period of time, preferably about 30-100 seconds.