Intel Corporation (Santa Clara, CA) in U.S. Patent 7,615,476 discloses electromigration-resistant and compliant wire interconnects, nano-sized solder compositions, and methods of assembling soldered packages. Inventor Fay Hua (Fremont, CA) developed nano-sized metal particle composites that includes a first metal that has a particle size of about 2 to 50 nanometers. A wire interconnect is in contact with a reflowed nanosolder and has the same metal or alloy composition as the reflowed nanosolder. A microelectronic package is also disclosed that uses the reflowed nanosolder composition. A method of assembling a microelectronic package includes preparing a wire interconnect template. A computing system includes a nanosolder composition coupled to a wire interconnect. A process comprising: forming a nano-particle solder paste on a substrate; contacting the nano-particle solder paste with a wire interconnect; and reflowing the nano-particle solder paste to form a solder bump in a wire interconnect article. the nano-particle solder paste is carried out with a metal particle selected from silver, copper, gold, a gold tin alloy, Au80Sn20, tin, tin-silver, and combinations of the metals.
An integrated circuit (IC) die is often fabricated into a processor for various tasks. IC operation invariably leads to heat generation and thermal expansion stresses in a die package. High melting point solder, although they withstand the high operating temperatures caused by the densely packed circuitry in a die, requires high processing temperature, which can cause high thermal-mechanical stress due to coefficient of thermal expansion (CTE) mismatch between semiconductive die and organic substrate. But for low melting solder, the electro-migration is much more easily to happen. Additionally, corrosion can occur between the two disparate metals of the solder bump and the bond pad.
Intel's reflowed nanosolder compositions can be applied to devices and apparatuses other than a traditional computer. For example, a die can be packaged with a reflowed nanosolder compositions, and placed in a portable device such as a wireless communicator or a hand-held device such as a personal data assistant and the like. Another example is a die that can be packaged with a reflowed nanosolder compositions and placed in a vehicle such as an automobile, a locomotive, a watercraft, an aircraft, or a spacecraft.