Semiconductor devices with embedded silicon lens

1 . A semiconductor device, comprising:

a silicon substrate having a first region and a second region;

a silicon lens formed in the first region and along a surface of the silicon substrate on a first side of the silicon substrate, wherein the silicon substrate includes a staircase profile in the first region, the staircase profile comprising at least a central portion having a first depth and a recessed portion surrounding the central portion and having a second depth less than the first depth, and wherein the staircase profile is rounded such that the rounded staircase profile defines the silicon lens;

a dielectric layer disposed in the first region and on a second side of the silicon substrate, the second side being opposite to the first side wherein the silicon lens is formed;

an electronic die disposed in the second region, on the second side of the silicon substrate, and adjacent to the dielectric layer;

a photonic die disposed in the first and second regions and on the second side of the silicon substrate, wherein the dielectric layer and the electronic die are interposed between the photonic die and the silicon substrate; and

a waveguide disposed on the second side of the silicon substrate and having a grating coupler.

2 . The semiconductor device of claim 1 , wherein the grating coupler is defined by recesses in the waveguide.

3 . The semiconductor device of claim 1 , wherein the silicon substrate and the silicon lens are integrally formed as a one-piece.

4 . The semiconductor device of claim 1 , wherein the silicon lens is configured to provide a focal point at the grating coupler.

5 . The semiconductor device of claim 1 , wherein the grating coupler is configured to allow the waveguide to receive light through the silicon lens.

6 . The semiconductor device of claim 1 , wherein the photonic die comprises a plurality of conductive features.

7 . The semiconductor device of claim 6 , wherein an optical transmission path extending from the grating coupler to the silicon lens is free from the plurality of conductive features.

8 . The semiconductor device of claim 1 , further comprising:

a plurality of conductive connectors disposed on a first side of the photonic die opposite to its second side that faces the silicon substrate; and

a package substrate coupled to the photonic die via at least the plurality of conductive connectors.

9 . The semiconductor device of claim 1 , wherein at least one of ammonia solution or nitric acid solution is applied over the surface of the silicon substrate to round the staircase profile.

10 . The semiconductor device of claim 1 , wherein the silicon lens is formed with a plano-convex profile.

11 . The semiconductor device of claim 1 , wherein the silicon lens has at least one of:

a diameter in a range of about 100 micrometers (μm) to about 200 μm,

a curve radius in a range of about 100 μm to about 500 μm,

an angle at edges of the silicon lens in a range of about 5 degrees to 15 degrees, or

a maximum thickness in a range of about 1 μm to about 50 μm.

12 . A semiconductor package, comprising:

a first substrate disposed over a package substrate;

a grating coupler disposed over the first substrate;

a plurality of first conductive features disposed in a layer over the grating coupler;

an electronic die disposed over the plurality of first conductive features and including a plurality of second conductive features;

a dielectric layer disposed over the grating coupler and adjacent to the electronic die; and

a silicon lens embedded along a first surface of a silicon substrate, wherein the silicon substrate includes a staircase profile that comprises at least a central portion having a first depth and a recessed portion surrounding the central portion and having a second depth less than the first depth, and wherein the staircase profile is rounded such that the rounded staircase profile defines the silicon lens, wherein the electronic die and the dielectric layer are formed along a second surface of the silicon substrate opposite to the first surface, and wherein the electronic die and the dielectric layer are interposed between the silicon substrate and the grating coupler.

13 . The semiconductor package of claim 12 , wherein the silicon lens is vertically aligned with the grating coupler.

14 . The semiconductor package of claim 12 , wherein the silicon lens is configured to provide a focal point at the grating coupler.

15 . The semiconductor package of claim 12 , wherein an optical transmission path extending from the grating coupler to the silicon lens is free from any of the plurality of first conductive features or the plurality of second conductive features.

16 . The semiconductor package of claim 10 , further comprising:

a plurality of first conductive connectors interposed between the first substrate and the package substrate; and

a plurality of second conductive connectors formed along a first surface of the package substrate opposite to its second surface that faces the first substrate.

17 . The semiconductor package of claim 12 , wherein the silicon lens comprises a surface having at least one region surrounding a top point, wherein the at least one region is lower than the top point of the silicon lens.

18 . The semiconductor package of claim 17 , wherein the silicon lens has at least one of:

a diameter in a range of about 100 micrometers (μm) to about 200 μm, a curve radius in a range of about 100 μm to about 500 μm, an angle at edges of the silicon lens in a range of about 5 degrees to 15 degrees, or a maximum thickness in a range of about 1 μm to about 50 μm.

19 . A semiconductor device, comprising:

a silicon substrate having a first side and a second side opposite to the first side, wherein the silicon substrate comprises a silicon lens formed along a surface of the silicon substrate and on the first side of the silicon substrate, wherein the silicon substrate includes a staircase profile that comprises at least a central portion having a first depth and a recessed portion surrounding the central portion and having a second depth less than the first depth, and wherein the staircase profile is rounded such that the rounded staircase profile defines the silicon lens;

a dielectric layer disposed on the second side of the silicon substrate;

an electronic die disposed on the second side of the silicon substrate and adjacent to the dielectric layer; and

a photonic die disposed on the dielectric layer, wherein the dielectric layer and the electronic die are interposed between the silicon substrate and the photonic die, wherein a width of the silicon substrate is greater than a width of the dielectric layer or a width of the electronic die.

20 . The semiconductor device of claim 19 , wherein:

the photonic die comprises a waveguide,

the waveguide is positioned below the dielectric layer, and

the semiconductor device further comprises a grating coupler defined by recesses in the waveguide.