Northrop Grumman Systems Corporation

Salim Akbany

Dean Tran

Ronald A DePace

William L Jones

Maurice Lowery

Roosevelt Johnson

Leon M Singleton, Jr

A chip or die attachment process and related apparatus, in which a desired quantity of solder (or) is dispensed onto each, in turn, of a number of desired locations on a substrate (or), and then an integrated-circuit chip () is precisely positioned at each location immediately after the solder is dispensed at that location. Hot gas heaters are used both to heat the solder (or) as it is dispensed onto the substrate (or), and to heat the integrated-circuit chip () and to reflow the solder beneath the chip. In one form of the invention, the solder is dispensed from a wire spool () and melted in position on the substrate (). Alternatively, the solder is dispensed as a drop () from a liquid solder reservoir ().

Thermal solder writing eutectic bonding process and apparatus

A relatively simple and inexpensive process for plating precious alloyed metals, such as AuSn, AuSnIn, AgSn, AuIn and AgIn. Anodes are formed from each of the metal components in the alloy and disposed in a conducting solution. The mass of each metal components is determined by Faraday's law. The target is also disposed in the conducting solution. Plating current is independently applied to each anode. The plating is conducted under an ultraviolet light sources to optimize the process. The plating alloys can be used for various purposes including attaching a semiconductor die to a substrate. Since the process does not involve exposure of the semiconductor die to a relatively high temperature for a relatively long time, the process does not pose a risk of contamination of the semiconductor by the adhesive or wax used to hold the die in place on the carrier during processing. Moreover, unlike earlier known processes which utilize epoxy, the precious alloyed metals do not wet the entire die but only the metal contact areas, thus avoiding potential short circuit to the die.

Precious alloyed metal solder plating process

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Diamond Bar, CA, United States of America

Salim Akbany