PACKAGING STRUCTURES AND PACKAGING METHODS FOR ULTRASOUND-ON-CHIP DEVICES
A method of forming a multiple layer, hybrid interposer structure includes forming a plurality of first openings through a substrate, the substrate comprising a heat spreading material; forming a first metal material within the plurality of first openings and on top and bottom surfaces of the substrate; patterning the first metal material; forming a dielectric layer over the patterned first metal material; forming a plurality of second openings within the dielectric layer to expose portions of the patterned first metal material on the top and bottom surfaces of the substrate; filling the plurality of second openings with a second metal material, in contact with the exposed portions of the patterned first metal material; forming a third metal material on the top and bottom surfaces of the substrate, the third metal material in contact with the second metal material and the dielectric layer; and patterning the third metal material.
1 . A method of forming a multiple layer, hybrid interposer structure, the method comprising:
forming a plurality of first openings through a substrate, the substrate comprising a heat spreading material;
forming a first metal material within the plurality of first openings and on top and bottom surfaces of the substrate;
patterning the first metal material on the top and bottom surfaces of the substrate;
forming a dielectric layer over the patterned first metal material on the top and bottom surfaces of the substrate;
forming a plurality of second openings within the dielectric layer to expose portions of the patterned first metal material on the top and bottom surfaces of the substrate;
filling the plurality of second openings with a second metal material, in contact with the exposed portions of the patterned first metal material;
forming a third metal material on the top and bottom surfaces of the substrate, the third metal material in contact with the second metal material and the dielectric layer; and
patterning the third metal material.
2 . The method of claim 1 , wherein the substrate comprises a ceramic material.
3 . The method of claim 2 , wherein the ceramic material comprises aluminum nitride (AlN).
4 . The method of claim 1 , wherein filling the plurality of second openings with the second metal material comprises:
depositing the second metal material in the plurality of second openings and over the dielectric layer; and
performing chemical mechanical planarization (CMP) of the second metal material down to the dielectric layer.
5 . A method of forming a packaging structure for an ultrasonic transducer device, the method comprising:
attaching a multiple layer, flex substrate to a carrier wafer;
bonding a first side of an ultrasound-on-chip device to the flex substrate;
bonding a second side of the ultrasound-on-chip device to a first side of a hybrid substrate that provides both heat spreading and signal distribution; and
removing the carrier wafer.
6 . The method of claim 5 , further comprising applying an underfill material around the ultrasound-on-chip device, between the multiple layer, flex substrate and the hybrid substrate.
7 . The method of claim 5 , wherein the hybrid substrate comprises a ceramic material having vias formed therein.
8 . The method of claim 7 , further comprising bonding a second side of the hybrid substrate to a printed circuit board (PCB).