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

• US 8,138,027 B2
• Filed: 03/07/2008
• Issued: 03/20/2012
• Est. Priority Date: 03/07/2008
• Status: Active Grant

• Current Assignee: Stats Chippac Pte. Ltd. (JCET Group Co., Ltd.)
• Original Assignee: Stats Chippac Limited
• Inventors: Camacho, Zigmund R., Bathan, Henry D., Tay, Lionel Chien Hui, Trasporto, Arnel Senosa
• Primary Examiner(s): Richards, N Drew
• Assistant Examiner(s): SINGAL, ANKUSH K
• Application Number:
  US12/044,688
• Publication Number:
  US 20090224386A1
• Time in Patent Office: 1,474 Days
• Field of Search: 438/127
• US Class Current: 438/127
• CPC Class Codes: H01L 21/563 Encapsulation of active face of flip-chip device, e.g. underfilling or underencapsulation of flip-chip, encapsulation preform on chip or mounting substrate
• CPC Class Codes: H01L 2224/05571 the external layer being disposed in a recess of the surface
• CPC Class Codes: H01L 2224/05573 Single external layer
• CPC Class Codes: H01L 2224/05599 Material
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/16245 the item being metallic
• CPC Class Codes: H01L 2224/32245 the item being metallic
• CPC Class Codes: H01L 2224/48091 Arched
• CPC Class Codes: H01L 2224/48247 connecting the wire to a bond pad of the item
• CPC Class Codes: H01L 2224/73203 Bump and layer connectors
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 23/3121 a substrate forming part of the encapsulation
• CPC Class Codes: H01L 24/32 of an individual layer connector
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/00012 Relevant to the scope of the group, the symbol of which is combined with the symbol of this group
• CPC Class Codes: H01L 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/01029 Copper [Cu]
• CPC Class Codes: H01L 2924/01078 Platinum [Pt]
• CPC Class Codes: H01L 2924/01079 Gold [Au]
• CPC Class Codes: H01L 2924/14 : Integrated circuits
• CPC Class Codes: H01L 2924/15151 : the die mounting substrate comprising an aperture, e.g. for underfilling, outgassing, window type wire connections
• CPC Class Codes: H01L 2924/181 : Encapsulation
• CPC Class Codes: H01L 31/0203 : Containers; Encapsulations , e.g. encapsulation of photodiodesfor photovoltaic devices H01L31/048; for organic photosensitive devices H10K30/80

Abstract

A semiconductor device is made by providing a semiconductor die having an optically active area, providing a leadframe or pre-molded laminated substrate having a plurality of contact pads and a light transmitting material disposed between the contact pads, attaching the semiconductor die to the leadframe so that the optically active area is aligned with the light transmitting material to provide a light transmission path to the optically active area, and disposing an underfill material between the semiconductor die and leadframe. The light transmitting material includes an elevated area to prevent the underfill material from blocking the light transmission path. The elevated area includes a dam surrounding the light transmission path, an adhesive ring, or the light transmission path itself can be the elevated area. An adhesive ring can be disposed on the dam. A filler material can be disposed between the light transmitting material and contact pads.

Claims

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.