Embedded TiNxOy thin-film resistors in a build-up CSP for 10 Gbpsoptical transmitter and receiver modules

摘要

Integral passive components provide efficient circuitminiaturization while maintaining high performance and reducing assemblycosts. The development of practical integral passive components,however, requires advances in the areas of materials, low-costprocesses, and structural design. We have developed new TiNxOy thin-filmresistors, as well as a termination resistor-embedded CSP, and a processfor fabricating integral passive components. Our TiNxOy films exhibit asheet resistivity in the range of 30-5 k 22/square. To keep costs low,we have made the fabrication process compatible with that for MCM-D/L.Resistors as small as 25 μm square have been successfully producedwith this process. The Chip Scale Package (CSP) with embedded resistorshas been designed for 10 Gbps optical transmitter and receiver modules.A fabricated version shows excellent return loss for its terminationresistor, less than -20 dB in the frequency range of 50 MHz -14 GHz, andits resistors performed high reliability in constant voltage stresstests, with less than 5% change in resistance at 800 mW/mm2over 1000 hours