Abstract:
A method of flip-chip mounting a circuit device (12) to a substrate (10) in a manner that avoids damage and impairment of a fragile or otherwise sensitive element (30) on the device (12) facing the substrate (10), and a circuit assembly (60) produced thereby. The assembly (60) includes a substrate (10) having at least two sets of bonding sites (16) spaced apart from each other to define an intermediate surface region (18) therebetween. The device (12) is attached to the bonding sites (16) with solder connections (56,58), with the solder connections (56,58) being present on a surface of the device (12) that faces the substrate (10) and on which the element (30) is present so that the element (30) overlies the intermediate surface region (18) of the substrate (10). An underfill material (62) is present between the device (12) and the substrate (10) and encapsulates the solder connections (56,58). The underfill material (62) is separated from the intermediate surface region (18) of the substrate (10) so that the underfill material (62) does not contact the element (30).
Abstract:
An integrated sensor (10) comprising a thermopile transducer (12) and signal processing circuitry (4) that are combined on a single semiconductor substrate (20), such that the transducer output signal is sampled in close vicinity by the processing circuitry (14). The sensor (10) comprises a frame (18) formed of a semiconductor material that is not heavily doped, and with which a diaphragm (16) is supported. The diaphragm (16) has a first surface for receiving thermal (e.g., infrared) radiation, and comprises multiple layers that include a sensing layer containing at least a pair of interlaced thermopiles (22). Each thermopile (22) comprises a sequence of thermocouples (24), each thermocouple (24) comprising dissimilar electrically-resistive materials that define hot junctions (26) located on the diaphragm (16) and cold junctions (28) located on the frame (18). The signal processing circuitry (14) is located on the frame (18) and electrically interconnected with the thermopiles (22). The thermopiles (22) are interlaced so that the output of one of the thermopiles (22) increases with increasing temperature difference between the hot and cold junctions (26,28) thereof, while the output of the second thermopile (22) decreases with increasing temperature difference between its hot and cold junctions (26,28).