Research Triangle Institute

Daniel S Stevenson

Robert O Conn

David F Myers

Low temperature bond balls connect two structures having disparate coefficients of linear thermal expansion. An integrated circuit is made to heat the device such that the low temperature bond balls melt. After melting, the bond balls solidify, and the device is operated with the bond balls solidified. In one example, one of the two structures is a semiconductor substrate, and the other structure is a printed circuit board. The integrated circuit is a die mounted to the semiconductor substrate. The bond balls include at least five percent indium, and the integrated circuit is an FPGA loaded with a bit stream. The bit stream configures the FPGA such that the FPGA has increased power dissipation, which melts the balls. After the melting, a second bit stream is loaded into the FPGA and the FPGA is operated in a normal user-mode using the second bit stream.

In system reflow of low temperature eutectic bond balls

A TSV structure suitable for high speed signal transmission includes a metal strip portion that extends through a long and small diameter hole in a substrate. In one example, the metal strip portion is formed by laser ablating away portions of a metal sheath that lines a cylindrical sidewall of the hole, thereby leaving a longitudinal section of metal that is the metal strip portion. A second metal strip portion, that extends in a direction perpendicular to the hole axis, is contiguous with the metal strip portion that extends through the hole such that the two metal strip portions together form a single metal strip. Throughout its length, the single metal strip has a uniform width and thickness and therefore can have a controlled and uniform impedance. In some embodiments, multiple metal strips pass through the same TSV hole. In some embodiments, the structure is a coaxial TSV.

Growing community of inventors

Chapel Hill, NC, United States of America

Daniel S Stevenson