Flip-Chip interconnections using lead-free solders
Patent 6224690 Issued on May 1, 2001. Estimated Expiration Date: 
March 12, 2016. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
March 12, 2016. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesTin base lead-free solder composition containing bismuth, silver and antimony Process of making pad structure for solder ball limiting metallurgy having reduced edge stress High temperature, lead-free, tin based solder composition Method for making direct chip attach circuit card Patent #: 5634268 Inventors
ApplicationNo. 614984 filed on 03/12/1996US Classes:148/400, STOCK257/738, Ball shaped257/751, At least one layer forms a diffusion barrier257/753, With adhesion promoting means (e.g., layer of material) to promote adhesion of contact to an insulating layer257/766, At least one layer containing chromium or nickel257/E23.021Bump or ball contacts (EPO)ExaminersPrimary: Ip, SikyinAttorney, Agent or FirmForeign Patent References
International ClassC22C 007/00AbstractAn interconnection structure suitable for the connection of microelectronic circuit chips to packages is provided by this invention. In particular, the invention pertains to the area-array or flip-chip technology often called C4 (controlled collapse chip connection). The structure comprises an adhesion/barrier layer deposited on a passivated substrate (e.g., a silicon wafer), optionally an additional adhesion layer, a solderable layer of a metal selected from the group consisting of Ni, Co, Fe, NiFe, NiCo, CoFe and NiCoFe on the adhesion/barrier layer, and a lead-free solder ball comprising tin as the predominate component and one or more alloying elements selected from Bi, Ag, and Sb, and further optionally including one or more elements selected from the group consisting of Zn, In, Ni, Co and Cu.Other References
Field of SearchIron or manganese containingAntimony, or bismuth containing TIN BASE Ball shaped At least one layer forms a diffusion barrier With adhesion promoting means (e.g., layer of material) to promote adhesion of contact to an insulating layer At least one layer containing chromium or nickel Solder composition Flip chip Layered contact, lead or bond Semiconductor component Next to Co-, Fe-, or Ni-base component STOCK | |
