Carbon nanotube array as high impedance interconnects for sensing device integration

In next generation sensing architectures, compact systems that could enhance manoeuvrability and at the same time diversify sensing capability is similarly carried out through pitch size reduction to incorporate more pixels per unit area. This is because integration of these sensors to its Si read-out circuits has to be technologically compatible for proper signal digitization. In the case of metal interconnects, further down-scaling could lead to higher failure rate, mismatch in coefficient of thermal expansion. In this study, optical interconnects between the sensors and Si read-out circuits using vertically aligned carbon nanotubes arrays in place of indium bump arrays were investigated. Due to the low thermal budget of the sensing device and read-out circuits, vertically aligned carbon nanotube arrays were fabricated at low temperatures. Its material characteristics would be shown. The high dense carbon nanotubes were vertically bonded like in a flip-chip bonding process. Carbon nanotubes from the top chip were inserted between adjacent tubes of the bottom chip. As a result of the close proximity of individual tubes, such arrays could adhere the sensor to the read-out circuits due to stiction at the microscopic scale. This 'velcro' effect could be achieved due to its dense but fin-like structure. Individual bundles of interconnected carbon nanotubes could be equivalent to one pixel. Electro-optical measurements showing its feasibility of using it as optical interconnects for high impedance devices would be evaluated.