Freescale Semiconductor

About: Freescale Semiconductor is a based out in . It is known for research contribution in the topics: Layer (electronics) & Signal. The organization has 7673 authors who have published 10781 publications receiving 149123 citations. The organization is also known as: Freescale Semiconductor, Inc..

Failure Modes of Flip Chip Solder Joints Under High Electric Current Density

Abstract: The failure modes of flip chip solder joints under high electrical current density are studied experimentally. Three different failure modes are reported. Only one of the failure modes is caused by the combined effect of electromigration and thermomigration, where void nucleation and growth contribute to the ultimate failure of the module. The Ni under bump metallization–solder joint interface is found to be the favorite site for void nucleation and growth. The effect of pre-existing voids on the failure mechanism of a solder joint is also investigated

Advanced communication controller unit and method for recording protocol events

Abstract: An advanced communication controller unit for a distributed communication system having a plurality of communication controller units, at least one being an advanced communication controller unit, each coupled to a communication medium and adapted to communicate using a communication is presented. The advanced communication controller unit comprises a protocol event recording circuit having a monitoring input connected to at least one protocol event data transmission path of the advanced communication controller unit and a debug output connected to a memory device; and adapted to filter protocol event data received from the monitoring input depending on at least one configuration parameter and to provide filtered protocol event data to the debug output. A method for recording protocol events using a protocol event recording circuit in an advanced communication controller unit and a vehicle comprising at least one advanced communication controller unit are also disclosed.

Electromigration statistics and damage evolution for Pb-free solder joints with Cu and Ni UBM in plastic flip-chip packages

Abstract: A series of electromigration (EM) tests were performed as a function of temperature and current density to investigate lifetime statistics and damage evolution for Pb-free solder joints with Cu and Ni under-bump-metallizations (UBMs). The EM lifetime was found to depend on the failure criterion used, so the results were compared based on the first resistance jump and conventional open-failure criterion. Solder joints with Cu UBM had a longer lifetime than Ni UBM based on the open-failure criterion, but the lifetime with Ni UBM became comparable when the first resistance jump criterion was applied. To determine the temperature in solder joints, the Joule heating effect was investigated with experiments and finite element analysis. The temperature of solder joints was determined to be approximately 15°C higher than that at the Si die surface when 1 A of current was applied. With the appropriate temperature correction, the activation energies and the current density exponents were found to be Q = 1.11 eV, n = 3.75 and Q = 0.86 eV, n = 2.1 based on the open-failure criterion for solder joints with Cu and Ni UBM, respectively. Based on the first resistance jump criterion, Q = 1.05 eV, n = 1.45 for Cu UBM and Q = 0.94 eV, n = 2.2 for Ni UBM, respectively. For solder joints with Cu UBM, voids were formed initially at the Cu6Sn5/solder interface while the final open failure occurred at the Cu3Sn/Cu6Sn5 interface. For Ni UBM, voids were formed initially at the Ni3Sn4/solder interface leading to failure at the same interface. The formation of intermetallic compounds (IMCs) was enhanced under current stressing, which followed linear growth kinetics with time. The IMC growth was accompanied by volume shrinkage, which accelerated damage evolution under EM.

Pilot signal in an FDMA communication system

Abstract: Methods (500, 800) and corresponding systems (100, 200, 300, 400, 900) for generating a pilot symbol (330) include providing an M-point parallel transform sequence that is a discrete Fourier transform of a CAZAC sequence (312, 504-508). The M-point parallel transform sequence (312) is distributed (316, 510) to a set of M subcarriers among N subcarriers to form an N-point frequency-domain sequence (318) wherein the M subcarriers are evenly spaced apart. An N-point inverse fast Fourier transform (320, 512) is performed to convert the N-point frequency-domain sequence to an N-point time-domain sequence (322). The N-point time-domain sequence is converted (324, 514) to a serial sequence (326), and a cyclic prefix is added (328, 516) to the serial sequence to form a pilot symbol (330).

Monolithic microwave integrated circuits

Abstract: Low Q associated with passive components of monolithic integrated circuits (ICs) when operated at microwave frequencies can be avoided or mitigated using high resistivity (e.g., ≧100 Ohm-cm) semiconductor substrates and lower resistance inductors for the IC. This eliminates significant in-substrate electromagnetic coupling losses from planar inductors and interconnections overlying the substrate. The active transistor(s) are formed in the substrate proximate the front face. Planar capacitors are also formed over the front face of the substrate. Various terminals of the transistor(s), capacitor(s) and inductor(s) are coupled to a ground plane on the rear face of the substrate using through-substrate-vias to minimize parasitic resistance. Parasitic resistance associated with the planar inductors and heavy current carrying conductors is minimized by placing them on the outer surface of the IC where they can be made substantially thicker and of lower resistance. The result is a monolithic microwave IC previously unobtainable.