PROXIMITY DETECTOR DEVICE WITH INTERCONNECT LAYERS AND RELATED METHODS

Abstract

A proximity detector device may include a first interconnect layer including a first dielectric layer, and first electrically conductive traces carried thereby, an IC layer above the first interconnect layer and having an image sensor IC, and a light source IC laterally spaced from the image sensor IC. The proximity detector device may include a second interconnect layer above the IC layer and having a second dielectric layer, and second electrically conductive traces carried thereby. The second interconnect layer may have first and second openings therein respectively aligned with the image sensor IC and the light source IC. Each of the image sensor IC and the light source IC may be coupled to the first and second electrically conductive traces. The proximity detector device may include a lens assembly above the second interconnect layer and having first and second lenses respectively aligned with the first and second openings.

Claims

1. A device, comprising: a first interconnect layer comprising a first dielectric layer and a plurality of first electrically conductive traces; an integrated circuit (IC) layer overlying the first interconnect layer and comprising an image sensor IC and a light source IC laterally spaced from the image sensor IC; a second interconnect layer overlying the IC layer and comprising a second dielectric layer and a plurality of second electrically conductive traces, the second interconnect layer having first and second openings respectively aligned with the image sensor IC and the light source IC, the image sensor IC and the light source IC being electrically coupled to the plurality of first electrically conductive traces and the plurality of second electrically conductive traces; a transparent adhesive material, separate from the second dielectric layer, filling the first and second openings and contacting surfaces of the image sensor IC and the light source IC; a lens assembly overlying the second interconnect layer and comprising first and second lenses respectively aligned with the first and second openings, the first and second lenses being adhered to the transparent adhesive material; and a plurality of contacts coupled respectively to the plurality of first electrically conductive traces.

2. The device of claim 1, wherein the plurality of contacts comprises a plurality of ball grid array (BGA) contacts.

3. The device of claim 1, wherein a surface of the first interconnect layer directed away from the IC layer is coplanar to a surface of the plurality of first electrically conductive traces.

4. The device of claim 1, wherein the IC layer further comprises encapsulation material laterally surrounding the image sensor IC and the light source IC.

5. The device of claim 4, wherein the encapsulation material comprises a plurality electrically conductive vias each coupled between a respective aligned pair of the pluralities of first and second electrically conductive traces.

6. The device of claim 1, wherein the first and second openings have sidewalls defined by at least the second dielectric layer.

7. The device of claim 1, wherein the lens assembly further comprises a molding compound surrounding the first and second lenses, and having third and fourth openings aligned with respective ones of the first and second lenses.

8. The device of claim 1, wherein the transparent adhesive material completely fills the first and second openings.

9. The device of claim 8, wherein at least a portion of the transparent adhesive material extends into a portion of the lens assembly.

10. A device, comprising: a first interconnect layer comprising a plurality of first electrically conductive traces; a plurality of ball grid array (BGA) contacts coupled to a first surface of the plurality of first electrically conductive traces; an integrated circuit (IC) layer over a second surface of the plurality of first electrically conductive traces and comprising: an image sensor IC; a light source IC laterally spaced from the image sensor IC; and an encapsulant laterally surrounding the image sensor IC and the light source IC; a second interconnect layer over the IC layer and comprising a plurality of second electrically conductive traces, the second interconnect layer having first and second openings defined by a dielectric material of the second interconnect layer, the first and second openings being respectively aligned with the image sensor IC and the light source IC; a lens assembly above the second interconnect layer and comprising first and second lenses respectively aligned with the first and second openings; and a transparent adhesive material completely filling the first and second openings of the second interconnect layer, the transparent adhesive material having surfaces adhered to the first and second lenses, the image sensor IC, and the light source IC.

11. The device of claim 10, wherein the first lens comprises a filter lens.

12. The device of claim 10, wherein the light source IC comprises a light emitting diode.

13. The device of claim 10, further comprising a plurality of electrically conductive vias, each coupled between a respective aligned pair of the plurality of first electrically conductive traces and the plurality of second electrically conductive traces.

14. The device of claim 10, wherein the lens assembly further comprises a molding compound laterally surrounding the first and second lenses, the molding compound having first and second openings aligned with respective ones of the first and second lenses.

15. A method of forming a device, the method comprising: forming a first interconnect layer comprising a plurality of first electrically conductive traces carried thereby; forming an integrated circuit (IC) layer over the first interconnect layer and comprising: an image sensor IC; and a light source IC laterally spaced from the image sensor IC; forming a second interconnect layer over the IC layer, the second interconnect layer comprising a plurality of second electrically conductive traces and having first and second openings having sidewalls defined by dielectric material of the second interconnect layer, the first and second openings respectively aligned with the image sensor IC and the light source IC; filling the first and second openings of the second interconnect layer with a transparent adhesive material, the transparent adhesive material contacting the image sensor IC and light source IC; forming a lens assembly over the second interconnect layer and comprising first and second lenses respectively aligned with the first and second openings and adhered to the transparent adhesive material; and forming a plurality of contacts coupled respectively to the plurality of first electrically conductive traces.

16. The method of claim 15, wherein the forming of the IC layer comprises: forming an adhesive layer over a carrier; placing the image sensor IC and the light source IC over the adhesive layer; and forming encapsulation material to laterally surround the image sensor IC and the light source IC.

17. The method of claim 16, wherein the forming of the IC layer further comprises: forming a plurality electrically conductive vias in the encapsulation material, each electrically conductive via coupled between a respective aligned pair of the plurality of first electrically conductive traces and the plurality of second electrically conductive traces.

18. The method of claim 15, wherein the forming of the lens assembly further comprises: forming a molding compound to surround the first and second lenses; and forming third and fourth openings aligned with respective ones of the first and second lenses.

19. The method of claim 15, wherein the plurality of contacts comprises a plurality of ball grid array (BGA) contacts.

20. The method of claim 15, wherein the light source IC comprises a light emitting diode.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0015] For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:

[0016] FIG. 1 is a schematic cross-sectional view of a proximity detector device, according to the prior art.

[0017] FIG. 2 is a schematic cross-sectional view of a proximity detector device, according to the present disclosure.

[0018] FIG. 3 is a flowchart of a method for making the proximity detector device of FIG. 2.

[0019] FIGS. 4-13 are schematic cross-sectional views of steps for making the proximity detector device of FIG. 2.

[0020] FIGS. 14-16 are schematic cross-sectional views of steps for making another embodiment of the proximity detector, according to the present disclosure.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

[0021] The present embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which preferred embodiments of the present disclosure are shown. This present embodiments may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the present embodiments to those skilled in the art. Like numbers refer to like elements throughout, and prime notation is used to indicate similar elements in alternative embodiments.

[0022] Referring initially to FIG. 2, a proximity detector device 40 according to the present disclosure is now described. The proximity detector device 40 illustratively includes a first interconnect layer 41 comprising a first dielectric layer 45, and a plurality of first electrically conductive traces 48a-48b carried thereby. The proximity detector device 40 illustratively includes an IC layer 42 above the first interconnect layer 41 and comprising an image sensor IC 56, and a light source IC 55 laterally spaced from the image sensor IC. The light source IC 55 may comprise a light emitting diode (LED), such as an infrared LED.

[0023] The proximity detector device 40 illustratively includes a second interconnect layer 43 above the IC layer 42 and comprising a second dielectric layer 46, and a plurality of second electrically conductive traces 51a-51b carried thereby. The second interconnect layer 43 illustratively includes first openings 62a-62b and a second opening 61 therein respectively aligned with the image sensor IC 56 and the light source IC 55. Each of the image sensor IC 56 and the light source IC 55 is coupled to the pluralities of first 48a-48b and second 51a-51b electrically conductive traces.

[0024] In the illustrated embodiment, the first openings 62a-62b are illustratively aligned with the image sensor IC 56. The pair of first openings 62a-62b provides the imaging sensor IC 56 with access to the first and second lenses cavities.

[0025] The proximity detector device 40 illustratively includes a lens assembly 44 above the second interconnect layer 43. The lens assembly 44 illustratively includes first 53 and second 52 lenses respectively aligned with the first openings 62a-62b and the second opening 61.

[0026] In particular, the IC layer 42 includes encapsulation material 47 laterally surrounding the image sensor IC 56 and the light source IC 55. The encapsulation material 47 illustratively includes a plurality electrically conductive vias 50a-50b passing therethrough. Each electrically conductive via 50a-50b is coupled between a respective aligned pair of the pluralities of first 48a-48b and second 51a-51b electrically conductive traces.

[0027] The proximity detector device 40 illustratively includes transparent adhesive material 54a-54b in the first openings 62a-62b and the second opening 61 of the second interconnect layer. In the illustrated embodiment, the lens assembly 44 includes a molding compound 57 surrounding the first 53 and second 52 lenses. The lens assembly 44 illustratively includes first openings 59a-59b and a second opening 58 aligned with respective ones of the first 53 and second 52 lenses. In the illustrated embodiment, the first openings 59a-59b are aligned with the first lens 53.

[0028] Additionally, the proximity detector device illustratively includes a plurality of contacts 49a-49b (FIG. 16) coupled respectively to the plurality of first electrically conductive traces 48a-48b. For example, the plurality of contacts 49a-49b (FIG. 16) may comprise a plurality of BGA contacts. The first lens 53 may comprise a filter lens (e.g. glass filter or transparent sheet with filter coating). The first lens 53 may also comprise a focusing element in addition or alternatively.

[0029] Another aspect is directed to a method of making a proximity detector device 40. The method may comprise forming a first interconnect layer 41 comprising a first dielectric layer 45, and a plurality of first electrically conductive traces 48a-48b carried thereby. The method may include forming an IC layer 42 above the first interconnect layer 41 and comprising an image sensor IC 56, and a light source IC 55 laterally spaced from the image sensor IC. The method may include forming a second interconnect layer 43 above the IC layer 42 and comprising a second dielectric layer 46, and a plurality of second electrically conductive traces 51-51b carried thereby. The second interconnect layer may have first openings 62a-62b and a second 61 opening therein respectively aligned with the image sensor IC 56 and the light source IC 55, each of the image sensor IC and the light source IC being coupled to the pluralities of first 48a-48b and second 51-51b electrically conductive traces. The method may also include forming a lens assembly 44 above the second interconnect layer 43 and comprising first 53 and second 52 lenses respectively aligned with the first openings 62a-62b and the second opening 61.

[0030] Referring now additionally to FIGS. 3-16, a flowchart 70 illustrates a method for making the semiconductor device 20 (Block 71). In the illustrated embodiments, a wafer level processing technique for making a pair of identical proximity detector devices 40 is shown, but it should be appreciated that typical processes would include the manufacture of a large number of proximity detector devices (sometimes including varying embodiments in a single manufacturing process, i.e. the illustrated adjacent proximity detectors need not be identical). The method includes forming a carrier layer 90, and an adhesive layer 91 on the carrier layer (FIG. 4 and Block 73). The method includes positioning image sensor ICs 56 and light source ICs 55 on the adhesive layer 91 (FIG. 5 and Block 74). At this point, any other desired surface mount devices (e.g. capacitors) may also be positioned. The method includes forming an encapsulation material 47 on the image sensor ICs 56 and light source ICs 55 to define an IC layer 42 (FIG. 6 and Block 75).

[0031] The method includes flipping the IC layer 42 on the carrier layer 90 by heating the adhesive layer 91 to detach the IC layer and reapplying the IC layer to the adhesive layer on an opposite face thereof (FIG. 7 and Block 77). The method also includes forming a second interconnect layer 43 and a plurality of second electrically conductive traces 51a-51b carried thereby (FIG. 8 and Block 78).

[0032] The method includes forming a transparent adhesive material 54a-54b in first openings 62a-62b and the second opening 61 of the second interconnect layer 43. The method also includes positioning first 53 and second 52 lenses on the transparent adhesive material 54a-54b (FIG. 9 and Block 79).

[0033] The method includes forming molding compound 57 on the first 53 and second 52 lenses to define a lens assembly 44 (FIG. 10 and Block 80). In some embodiments, the forming of the molding compound 57 may be film assisted. The method includes flipping the IC 42 and second interconnect layers 43, and lens assembly 44 on the carrier layer 90 (FIG. 1i and Block 81) (again using a heating step to deactivate the adhesive layer 91). The method includes grinding a portion of the backside of the IC layer 42 (FIG. 12 and Block 82).

[0034] The method includes forming a first interconnect layer 41 comprising a first dielectric layer 45, and a plurality of first electrically conductive traces 48a-48b carried thereby (FIG. 13 and Block 84). In this embodiment, the plurality of first electrically conductive traces 48a-48b defines LGA contacts. The method also includes a singulation step (FIG. 15) (Blocks 84-86).

[0035] Advantageously, the proximity detector device 40 may be manufactured using robust wafer level processing techniques. Additionally, the proximity detector device 40 may be made in large quantities. Moreover, the structure is mechanically robust since the first 53 and second 52 lenses are tightly integrated with the lens assembly molding compound 57. Also, the lens assembly 44 is tightly integrated with the first 41, second 43 interconnect layers and the IC layer 43, also adding mechanical rigidity. The packaging of the proximity detector device 40 is thinner than typical approaches, thereby permitting easier integration into mobile devices. Moreover, the proximity detector device 40 provides for good co-planarity for the image sensor and light source ICs 55-56, thereby reducing the computational load of proximity detection calculations (i.e. from having adjacent source and receiver positions).

[0036] Referring now additionally to FIGS. 14-16, steps from another embodiment of the method for making the proximity detector device 40 is now described. In this embodiment of the method for making the proximity detector device 40, those steps and elements already discussed above with respect to FIGS. 2-13 are given prime notation and most require no further discussion herein. This embodiment differs from the previous embodiment in that this method illustratively includes forming a plurality of ball grid array contacts 49a-49b on the plurality of first electrically conductive traces 48a-48b (FIG. 14 and Block 85). The method illustratively includes a singulation step using a dicing blade 97 (FIGS. 15-16).

[0037] Many modifications and other embodiments of the present disclosure will come to the mind of one skilled in the art having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is understood that the present disclosure is not to be limited to the specific embodiments disclosed, and that modifications and embodiments are intended to be included within the scope of the appended claims.

[0038] While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.