Abstract: This invention provides a solution to increase the yield strength and fatigue strength of miniaturized springs, which can be fabricated in arrays with ultra-small pitches. It also discloses a solution to minimize adhesion of the contact pad materials to the spring tips upon repeated contacts without affecting the reliability of the miniaturized springs. In addition, the invention also presents a method to fabricate the springs that allow passage of relatively higher current without significantly degrading their lifetime.

Abstract: This invention provides a solution to increase the yield strength and fatigue strength of miniaturized springs, which can be fabricated in arrays with ultra-small pitches. It also discloses a solution to minimize adhesion of the contact pad materials to the spring tips upon repeated contacts without affecting the reliability of the miniaturized springs. In addition, the invention also presents a method to fabricate the springs that allow passage of relatively higher current without significantly degrading their lifetime.

Abstract: The method of the invention involves depositing a plurality of thin layers of film, each layer having a thickness ranging from about 500Å to about 2000Å. Low Pressure Chemical Vapor Deposition or other techniques known in the art maybe used to deposit each thin layer of film. The film is polysilicon or silicon-germanium, where the germanium content ranges from about 4% by weight to about 20% by weight germanium. A Rapid Thermal Anneal (“RTA”) is performed on a deposited thin film layer to relieve residual film stress in at least that film layer. The use of RTA rather than furnace annealing permits much shorter annealing times. Optionally, but advantageously, hydrogen may be present during RTA to permit the use of lower processing temperatures, typically about 20% lower relative to a customary anneal. A series of film deposition/rapid thermal anneal cycles is used to produce the desired, nominal total thickness polysilicon film.