Optical semiconductor device having pre-molded leadframe with window and method therefor

1. A method of making a semiconductor device, comprising:

providing an optical semiconductor die having an optically active area that generates electrical signals in response to the optically active area reacting to light;

providing a leadframe having a dam bar and a plurality of contact pads formed as fingers that extend away from the dam bar;

disposing a light transmitting material around the fingers and between the dam bar, the light transmitting material including an elevated area vertically offset with respect to the leadframe;

attaching the optical semiconductor die to the leadframe so that the optically active area of the optical semiconductor die is aligned with the light transmitting material to provide a light transmission path to the optically active area; and

disposing an underfill material around the light transmission path and between the optical semiconductor die and leadframe such that the underfill material contacts a sidewall of the elevated area.

2. The method of claim 1 , wherein the elevated area includes a dam surrounding the light transmission path.

3. The method of claim 1 , further including:

forming a plurality of vias in the optical semiconductor die; and

electrically connecting the plurality of vias to the leadframe.

4. The method of claim 1 , wherein the light transmitting material is formed as a convex lens.

5. The method of claim 1 , further including a filler material disposed between the light transmitting material and plurality of contact pads.

6. The method of claim 1 , further including a clear underfill material disposed between the light transmitting material and optically active area of the optical semiconductor die.

7. The method of claim 2 , further including forming a notch in the light transmitting material.

8. A method of making a semiconductor device, comprising:

providing an optical semiconductor die that generates electrical signals in response to light;

providing a leadframe having a light transmitting window, a plurality of contact pads formed as fingers around the light transmitting window, and an elevated area vertically offset with respect to the fingers;

attaching the optical semiconductor die to the leadframe so that the light transmitting window is aligned to an optically active area of the optical semiconductor die; and

disposing an underfill material between the optical semiconductor die and leadframe such that the underfill material contacts a sidewall of the elevated area.

9. The method of claim 8 , wherein the elevated area includes a dam surrounding the light transmitting window.

10. The method of claim 8 , further including:

forming a plurality of vias in the optical semiconductor die; and

electrically connecting the plurality of vias to the leadframe.

11. The method of claim 8 , further including forming a notch in the light transmitting window.

12. The method of claim 8 , wherein the light transmitting window is formed as a convex lens.

13. The method of claim 8 , wherein the elevated area includes a light transmitting material or an opaque filler material.

14. A method of making a semiconductor package, comprising:

providing an optical semiconductor die that generates electrical signals in response to light;

providing a substrate having a plurality of contact pads;

disposing a light transmitting material between the plurality of contact pads and the substrate, the light transmitting material including an elevated area vertically offset with respect to the substrate; and

attaching the optical semiconductor die to the substrate so that the light transmitting material is aligned to an optically active area of the optical semiconductor die.

15. The method of claim 14 , further including disposing an underfill material between the optical semiconductor die and substrate such that the underfill material contacts a sidewall of the elevated area to prevent the underfill material from blocking a light transmission path through the light transmitting material.

16. The method of claim 14 , wherein the substrate is a leadframe or pre-molded laminate substrate.

17. The method of claim 14 , wherein the light transmitting material is formed as a convex lens.

18. The method of claim 15 , wherein the elevated area is a dam surrounding the light transmission path.

19. A method of making a semiconductor package, comprising:

providing an optical semiconductor die;

providing a substrate having a plurality of contact pads;

disposing a light transmitting material between and substantially coplanar with the plurality of contact pads and the substrate;

attaching the optical semiconductor die to the substrate so that the light transmitting material is aligned to an optically active area of the optical semiconductor die;

forming a plurality of vias in the optical semiconductor die; and

electrically connecting the plurality of vias to the substrate.

20. A semiconductor package, comprising:

an optical semiconductor die; and

a substrate having a plurality of contact pads and a light transmitting material disposed between the contact pads such that a portion of the light transmitting material is vertically offset with respect to the contact pads, wherein the optical semiconductor die is attached to the substrate so that the light transmitting material is aligned to an optically active area of the optical semiconductor die.

21. The semiconductor package of claim 20 , further including an underfill material disposed between the optical semiconductor die and substrate, the vertically offset portion of the light transmitting material including an elevated area that prevents the underfill material from blocking a light transmission path through the light transmitting material.

22. The semiconductor package of claim 20 , further including:

a plurality of vias formed in the optical semiconductor die; and

a plurality of bond wires electrically connecting the plurality of vias to the substrate.

23. The semiconductor package of claim 20 , wherein the substrate is a leadframe or pre-molded laminate substrate.

24. The semiconductor package of claim 20 , further including a notch disposed in the light transmitting material.

25. The semiconductor package of claim 21 , wherein the elevated area includes a dam surrounding the light transmitting material.

26. A method of making a semiconductor device, comprising:

providing an optical semiconductor die that generates electrical signals in response to light;

providing a leadframe having a plurality of contact pads and an elevated area disposed around a light transmitting window;

attaching the optical semiconductor die to the plurality of contact pads so that the light transmitting window is aligned to an optically active area of the optical semiconductor die; and

disposing an underfill material between the optical semiconductor die and leadframe such that the underfill material contacts a sidewall of the elevated area.

27. The method of claim 26 , wherein the elevated area includes a light transmitting material or an opaque filler material.

28. The method of claim 26 , wherein the elevated area includes a dam surrounding the light transmitting window.

29. The method of claim 26 , wherein disposing the underfill material includes disposing a clear underfill material between the light transmitting window and the optical semiconductor die.

30. The method of claim 26 , further including forming a notch in the light transmitting window.

31. The method of claim 26 , wherein the light transmitting window is formed as a convex lens.