Smart Packaging - Microscopic Temperature and Moisture Sensors Embedded in a Flip-Chip Package

The interest in very-large-scale integration technology combined with market pressure to reduce materials and process costs introduce new packaging yield and reliability challenges. The use of organic substrates in flip-chip packages, rather than ceramics, led to thermal and moisture related issues. The organic laminate coefficient of thermal expansion substantially differs from the chip one, potentially leading to interfacial delamination and interconnect rupture. Moreover, organic substrates are permeable to water, potentially leading to electrochemical migration, corrosion of alloys, delamination and short-circuits. Thus temperature and moisture variation can have baneful consequences on flip-chip packages. Here, the internal module temperature and moisture quantities of a flip-chip package are measured using microscopic embedded carbon nanotube-based sensors. Those sensors are fabricated near interconnects and are positioned to provide spatial and real-time mapping of moisture and temperature in the package, for a better interconnect reliability study or package aging monitoring.