Solid state photomultipliers array of enhanced fill factor and simplified packaging

Patent metadata

Field	Value
Publication number	US-9466631-B2
Application number	US-201514704070-A
Country	US
Kind code	B2
Filing date	May 5, 2015
Priority date	May 13, 2014
Publication date	Oct 11, 2016
Grant date	Oct 11, 2016

Abstract

A multi-pixel photomultiplier optical sensor may include an array of photomultiplier dies. Each photomultiplier die may include a front side connection pad, SPAD cells, each SPAD cell including a front side electrode, a rear side electrode, and a resistor coupled in series to the front side electrode and coupled in common with other quenching resistors to the front side connection pad. The multi-pixel photomultiplier optical sensor may include a metallization layer in contact with the rear side electrode common to SPADs of the array of photomultiplier dies and electrically conductive pads. The electrically conductive bus may be coupled to an electrically conductive pin for distributing bias current to the array of photomultiplier dies. The multi-pixel photomultiplier optical sensor may include electrically conductive bond wires coupling at least some of the electrically conductive pads to the electrically conductive bus, and distributing bias current to the array of photomultiplier dies via the electrically conductive bus.

First claim

That which is claimed is:

1. A multi-pixel photomultiplier optical sensor comprising:
a multilevel printed circuit board;
a plurality of electrically conductive traces carried by said multilevel printed circuit board;
a plurality of electrically conductive pads carried by said multilevel printed circuit board;
an electrically conductive bus carried by said multilevel printed circuit board;
a plurality of electrically conductive pins carried by said multilevel printed circuit board and comprising a first group along a perimeter of said multilevel printed circuit board, and a second group on a surface of the multilevel printed circuit board;
each electrically conductive pin from said first group being coupled via said plurality of electrically conductive traces to said electrically conductive bus;
each electrically conductive pin from said second group being coupled via said plurality of electrically conductive traces to a respective electrically conductive pad;
an array of monolithic silicon photomultiplier (SiPM) dies, each monolithic SiPM die having a front side and a rear side;
each monolithic SiPM die comprising
a front side connection pad,
a plurality of single photon avalanche diode (SPAD) cells optically isolated from one another, each SPAD cell including
a front side electrode,
a rear side electrode, and
a resistor coupled in series to said front side electrode and coupled in common with all other resistors to said front side connection pad, and

a metallization layer in contact with said rear side electrode and the respective electrically conductive pad from said plurality thereof;

said array of monolithic SiPM dies being positioned side-by-side;
said electrically conductive bus being coupled to at least one electrically conductive pin for uniformly distributing bias current to all of said array of monolithic SiPM dies; and
a plurality of electrically conductive bond wires coupling at least some of the plurality of electrically conductive pads to said electrically conductive bus, and distributing bias current to said array of monolithic SiPM dies via said electrically conductive bus.

2. The multi-pixel photomultiplier optical sensor of claim 1 wherein said front side connection pad of the array of monolithic SiPM dies extends along an edge portion of the front side; wherein said front side connection pad of the array of monolithic SiPM dies extends in at least one of a row wise and column wise direction; and wherein said plurality of electrically conductive bond wires couples said front side connection pad of the array of monolithic SiPM dies to said electrically conductive bus.

3. The multi-pixel photomultiplier optical sensor of claim 1 wherein said front side connection pad of the array of monolithic SiPM dies has a shape of a cross centered on each monolithic SiPM die; and further comprising additionally electrically conductive bond wires coupling ends of the cross to adjacent ones from adjacent monolithic SiPM dies.

4. The multi-pixel photomultiplier optical sensor of claim 1 wherein said front side connection pad comprises a plurality thereof adjacent respective corners of each monolithic SiPM die; and further comprising additionally electrically conductive bond wires coupling said some front side connection pads to adjacent ones from adjacent monolithic SiPM dies.

5. The multi-pixel photomultiplier optical sensor of claim 1 wherein said metallization layer is bonded in electrical contact with said plurality of electrically conductive pads with at least one of solder and electrically conductive structural adhesive.

6. The multi-pixel photomultiplier optical sensor of claim 1 further comprising a transparent coating embedding the array of monolithic SiPM dies, and said electrically conductive bus.

7. A multi-pixel photomultiplier optical sensor comprising:
a circuit board;
a plurality of electrically conductive traces carried by said circuit board;
a plurality of electrically conductive pads carried by said circuit board;
an electrically conductive bus carried by said circuit board;
a plurality of electrically conductive pins carried by said circuit board and comprising first and second groups;
each electrically conductive pin from said first group being coupled via said plurality of electrically conductive traces to said electrically conductive bus;
each electrically conductive pin from said second group being coupled via said plurality of electrically conductive traces to a respective electrically conductive pad;
an array of photomultiplier dies, each photomultiplier die comprising
a front side connection pad,
a plurality of single photon avalanche diode (SPAD) cells, each SPAD cell including
a front side electrode,
a rear side electrode, and
a resistor coupled in series to said front side electrode and coupled in common with other resistors to said front side connection pad, and

a metallization layer in contact with said rear side electrode and the respective electrically conductive pad from said plurality thereof;

said electrically conductive bus being coupled to at least one electrically conductive pin for distributing bias current to said array of photomultiplier dies; and
a plurality of electrically conductive bond wires coupling at least some of the plurality of electrically conductive pads to said electrically conductive bus, and distributing bias current to said array of photomultiplier dies via said electrically conductive bus.

8. The multi-pixel photomultiplier optical sensor of claim 7 wherein said front side connection pad of the array of photomultiplier dies extends along an edge portion of the front side; wherein said front side connection pad of the array of photomultiplier dies extends in at least one of a row wise and column wise direction; and wherein said plurality of electrically conductive bond wires couples said front side connection pad of the array of photomultiplier dies to said electrically conductive bus.

9. The multi-pixel photomultiplier optical sensor of claim 7 wherein said front side connection pad of the array of photomultiplier dies has a shape of a cross centered on each photomultiplier die; and further comprising additionally electrically conductive bond wires coupling ends of the cross to adjacent ones from adjacent photomultiplier dies.

10. The multi-pixel photomultiplier optical sensor of claim 7 wherein said front side connection pad comprises a plurality thereof adjacent respective corners of each photomultiplier die; and further comprising additionally electrically conductive bond wires coupling said some front side connection pads to adjacent ones from adjacent photomultiplier dies.

11. The multi-pixel photomultiplier optical sensor of claim 7 wherein said metallization layer is bonded in electrical contact with said plurality of electrically conductive pads with at least one of solder and electrically conductive structural adhesive.

12. The multi-pixel photomultiplier optical sensor of claim 7 further comprising a transparent coating embedding the array of photomultiplier dies, and said electrically conductive bus.

13. A method for making a multi-pixel photomultiplier optical sensor comprising:
forming a plurality of electrically conductive traces carried by the circuit board;
forming a plurality of electrically conductive pads carried by the circuit board;
forming an electrically conductive bus carried by the circuit board;
forming a plurality of electrically conductive pins carried by the circuit board and comprising first and second groups;
each electrically conductive pin from the first group being coupled via the plurality of electrical

Assignees

• St Microelectronics Srl

Inventors

• Fallica Pierogiorgio
• Romeo Mariofrancesco
• Lo Presti Domenico

Classifications

• H10W74/00

  Encapsulations, e.g. protective coatings · CPC title

• H10W72/5363

  the connected ends being wedge-shaped · CPC title

• H10W72/884

  Die-attach connectors and bond wires · CPC title

• H10W70/656

  Fan-in layouts · CPC title

• H10F39/811

  Interconnections · CPC title