Optical die-down quad flat non-leaded package
View Patent ↗An optical sensor package that includes an optical sensor die is mounted by flip chip interconnect onto a lead frame in a “die-down” orientation, that is, with the active side of the optical sensor die facing the lead frame. An opening is provided in the lead frame die paddle (pad), and light passes from outside the package through the opening in the lead frame die pad onto light collection elements on the active side of the chip.
1. A method of making a low-profile optical sensor package, comprising:
providing a leadframe having a die pad and interconnect leads electrically isolated from and surrounding the die pad, the die pad having an opening centrally located with respect to a surface area of the die pad;
mounting a semiconductor die to the die pad, the semiconductor die having an optically active surface facing the die pad and aligned to the opening;
disposing a barrier layer around the opening and connecting the semiconductor die and die pad;
disposing an encapsulant over a portion of the semiconductor die and the leadframe, wherein the barrier layer isolates the encapsulant from the optically active surface of the semiconductor die; and
mounting a light-transmitting cover across the opening in the die pad;
wherein the low-profile optical sensor package has a thickness of less than 0.7 millimeters.
2. The method of claim 1 , wherein the barrier layer includes an adhesive material.
3. The method of claim 1 , wherein the opening is circular or rectangular.
4. The method of claim 1 , wherein the optically active surface includes a charge-coupled image sensor.
5. The method of claim 1 , wherein the optically active surface includes a monochrome image sensor.
6. The method of claim 1 , wherein the light-transmitting cover reduces the intensity of light transmitted through the opening to the optically active surface of the semiconductor die.
7. The method of claim 1 , wherein the low-profile optical sensor package is a quad flat non-leaded package.
8. A method of making a semiconductor package, comprising:
providing a leadframe having a die pad and interconnect leads electrically isolated from the die pad;
mounting a semiconductor die to the die pad, the semiconductor die having an optically active surface facing the die pad and aligned to a centrally located opening in the die pad;
disposing a barrier layer around the centrally located opening and connecting the semiconductor die and die pad;
disposing an encapsulant over a portion of the semiconductor die and the leadframe, wherein the barrier layer isolates the encapsulant from the optically active surface of the semiconductor die; and
mounting a light-transmitting cover across the centrally located opening in the die pad by etching the die pad to retain the light-transmitting cover.
9. The method of claim 8 , wherein the semiconductor package has a thickness of less than 0.7 millimeters.
10. The method of claim 8 , wherein the barrier layer includes an adhesive material.
11. The method of claim 8 , wherein the centrally located opening is circular or rectangular.
12. The method of claim 8 , wherein the optically active surface includes a charge-coupled image sensor.
13. The method of claim 8 , wherein the light-transmitting cover reduces the intensity of light transmitted through the centrally located opening to the optically active surface of the semiconductor die.
14. The method of claim 8 , wherein the semiconductor package is a quad flat nonleaded package.
15. A method of making an optical semiconductor package, comprising:
providing a leadframe having a die pad and interconnect leads electrically isolated from the die pad;
mounting a semiconductor die to the die pad, the semiconductor die having an optically active surface facing the die pad and aligned to an opening in the die pad;
disposing a barrier layer around the opening and connecting the semiconductor die and die pad;
disposing an encapsulant over a portion of the semiconductor die and the leadframe, wherein the barrier layer isolates the encapsulant from the optically active surface of the semiconductor die; and
mounting a light-transmitting cover across the opening in the die pad by etching the die pad to retain the light transmitting cover.
16. The method of claim 15 , wherein the semiconductor package has a thickness of less than 0.7 millimeters.
17. The method of claim 15 , wherein the barrier layer includes an adhesive material.
18. The method of claim 15 , wherein the optically active surface includes a charge-coupled image sensor.
19. The method of claim 15 , wherein the optical semiconductor package is a quad flat nonleaded package.
20. A method of making an optical semiconductor package, comprising:
providing a leadframe having a die pad and interconnect leads electrically isolated from the die pad;
mounting a semiconductor die to the die pad, the semiconductor die having an optically active surface facing the die pad and aligned to an opening in the die pad;
disposing a barrier layer around the opening and connecting the semiconductor die and die pad; and
disposing an encapsulant over a portion of the semiconductor die and the leadframe, wherein the barrier layer isolates the encapsulant from the optically active surface of the semiconductor die.
21. The method of claim 20 , further including mounting a light-transmitting cover across the opening in the die pad.
22. The method of claim 21 , further including etching the die pad to retain the light-transmitting cover.
23. The method of claim 21 , wherein the light-transmitting cover reduces the intensity of light transmitted through the opening to the optically active surface of the semiconductor die.
24. The method of claim 20 , wherein the semiconductor package has a thickness of less than 0.7 millimeters.
25. The method of claim 20 , wherein the semiconductor package is a quad flat nonleaded package.