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 fingerprint sensor package comprising:
a sensor die having a die top side, a die bottom side, and die lateral sides, wherein the sensor die comprises sensing electronics;
a sensing area on the die top side;
a top side trace, at least a portion of which is directly above the sensor die;
a bottom side trace, at least a portion of which is directly below the sensor die;
a conductive via that electrically connects the top side trace and the bottom side trace; an encapsulant that covers at least the die lateral sides;
and a protective layer that covers the sensing area;
wherein the protective layer is separated from the die top side by at least one intervening layer; wherein a lateral side of the protective layer, a lateral side of the at least one intervening layer, and a lateral side of the encapsulant are coplanar.
2. The fingerprint sensor package of claim 1 , wherein the protective layer covers the entire die top side.
3. The fingerprint sensor package of claim 2 , wherein the protective layer covers an entire top side of the encapsulant.
4. The fingerprint sensor package of claim 1 , wherein:
the protective layer comprises a plurality of lateral sides; and
the encapsulant comprises a plurality of lateral sides, each of which is coplanar with a respective one of the lateral sides of the protective layer.
5. The fingerprint sensor package of claim 1 , wherein the protective layer is less than 25 microns thick.
6. A fingerprint sensor package comprising:
a sensor die having a die top side, a die bottom side, and die lateral sides, w herein the sensor die comprises sensing electronics;
a sensing area on the die top side;
a top side trace, at least a portion of which is directly above the sensor die;
a bottom side trace, at least a portion of which is directly below the sensor die;
a conductive via that electrically connects the top side trace and the bottom side trace;
and an encapsulant that covers at least a portion of the die bottom side and covers at least a portion of each of the die lateral sides;
a connection point directly below the sensor die; and a conductive ball attached to the connection point,
Wherein an upper end of the conductive ball is higher than a lowest surface of the encapsulant, and a lower end of the conductive ball is lower than the lowest surface of the encapsulant.
7. The fingerprint sensor package of claim 6 , wherein the encapsulant covers the entire die bottom side.
8. The fingerprint sensor package of claim 6 , wherein a lowest surface of the encapsulant is at least as low as a lowest surface of the bottom side trace.
9. The fingerprint sensor package of claim 6 , wherein a top side of the encapsulant is substantially coplanar with the die top side.