Packaging for fingerprint sensors and methods of manufacture
A fingerprint sensor package, including a sensing side for sensing fingerprint information and a separate connection side for electrically connecting the fingerprint sensor package to a host device, is disclosed. The fingerprint sensor package can also include a sensor integrated circuit facing the sensing side and substantially surrounded by a fill material. The fill material includes vias at peripheral locations around the sensor integrated circuit. The fingerprint sensor package can further include a redistribution layer on the sensing side which redistributes connections of the sensor integrated circuit to the vias. The connections can further be directed through the vias to a ball grid array on the connection side. Some aspects also include electrostatic discharge traces positioned at least partially around a perimeter of the connection side. Methods of manufacturing are also disclosed.
1. A method of fabricating a biometric object sensor wafer level fan out package, the method comprising:
forming a sensor control integrated circuit;
forming a molded fill material to at least partially encapsulate the sensor control integrated circuit;
forming a sensing side redistribution layer, wherein the sensing side redistribution layer is disposed on a sensing side of the package, and wherein the sensing side redistribution layer comprises at least one passivation layer and a metal layer, wherein the metal layer of the sensing side redistribution layer further comprises metal redistribution traces and a metal sensor array in the sensing side redistribution layer, the metal sensor array further including a plurality of capacitively coupled drivers and pick-ups configured to detect ridges and valleys of a fingerprint;
forming a connection side redistribution layer, wherein the connection side redistribution layer is on an opposite side of the package relative to the sensing side;
forming at least one ball grid array electrical connector mounted on the connection side of the package; and
forming a protective coating on the sensing side of the package disposed on the sensing side redistribution layer.
2. The method of claim 1 , wherein the molded fill material completely encapsulates the integrated circuit.
3. The method of claim 1 , further comprising:
connecting the at least one ball grid array electrical connector to the sensing side of the package through a through mold via.
4. The method of claim 1 , wherein the connection side of the package comprises a printed circuit board disposed between the at least one ball grid array electrical connector and the sensor control integrated circuit.
5. The method of claim 1 wherein the molded fill material is formed in an opening in a printed circuit board containing the sensor control integrated circuit.
6. The method of claim 1 , wherein the package is a fingerprint sensor package.
7. The method of claim 1 , further comprising:
forming an interposer board, wherein the interposer board is disposed between the sensing side redistribution layer and the connection side redistribution layer.
8. The method of claim 1 , wherein the connection side redistribution layer comprising a multilayer printed circuit board.
9. The method of claim 1 , wherein the at least one passivation layer comprises a first passivation layer disposed between the sensor control integrated circuit and the metal layer.
10. The method of claim 9 , wherein the at least one passivation layer further comprises a second passivation layer, wherein the metal layer is disposed between the first passivation layer and the second passivation layer.
11. The method of claim 1 , further comprising:
forming a secondary integrated circuit, wherein the secondary integrated circuit is disposed within the molded fill material along with the sensor control integrated circuit.
12. The method of claim 11 , wherein the secondary integrated circuit includes a light emitting diode.