Semiconductor device and manufacturing method of the same

1. A semiconductor device comprising:

a first clad layer;

a first optical waveguide formed on the first clad layer;

a second clad layer formed on the first optical waveguide and the first clad layer, the second clad layer having an opening overlapping an end portion of the first optical waveguide in plan view;

a second optical waveguide optically connected with the first optical waveguide and formed in the opening; and

a third clad layer burying the opening and configured to surround the second optical waveguide,

wherein the third clad layer comprises:

a first resin portion formed in the opening such that the second optical waveguide is formed on the first resin, the first resin portion being composed of a material including resin; and

a second resin portion formed on the first resin portion such that the second resin portion covers the second optical waveguide, the second resin portion composed of a material including resin, and

wherein the second optical waveguide is configured to reach an upper surface of the third clad layer from the end portion of the first optical waveguide.

2. The semiconductor device according to claim 1 , wherein the second optical waveguide comprises:

an optical coupling portion optically connected with the first optical waveguide; and

a curved portion connected with the optical coupling portion and having a curved shape.

3. The semiconductor device according to claim 2 ,

wherein the optical coupling portion of the second optical waveguide and the end portion of the first optical waveguide have an overlapping portion with each other in plan view, and

wherein the optical coupling portion is disposed along the end portion of the first optical waveguide to be parallel with the first optical waveguide.

4. The semiconductor device according to claim 2 , wherein a cross-sectional area of the curved portion located in an upper surface side of the third clad layer is greater than a cross-sectional area of the curved portion located in an end portion side of the first optical waveguide, in a cross-sectional view perpendicular to an extending direction of the second optical waveguide.

5. The semiconductor device according to claim 2 , wherein a cross-sectional area of the curved portion located in a cross-sectional view perpendicular to an extending direction of the second optical waveguide increases as closing to the upper surface of the third clad layer.

6. The semiconductor device according to claim 2 ,

wherein a cross-sectional area of the second optical waveguide in an end portion of the optical coupling portion is 1 μm 2 or more and 10 μm 2 or less in a cross-sectional view perpendicular to an extending direction of the second optical waveguide, and

wherein a cross-sectional area of the second optical waveguide in the upper surface of the third clad layer is 20 μm 2 or more and 100 μm 2 or less in the cross-sectional view perpendicular to the extending direction of the second optical waveguide.

7. The semiconductor device according to claim 1 , wherein a width of the first optical waveguide in a direction perpendicular to an extending direction of the first optical waveguide decreases as closing to an end surface of the end portion of the first optical waveguide.

8. The semiconductor device according to claim 1 , further comprising:

a fourth clad layer formed on the second clad layer and the third clad layer;

a third optical waveguide optically connected with the second optical waveguide and formed on the fourth clad layer; and

a fifth clad layer covering the third optical waveguide and formed on the second, third and fourth clad layers,

wherein the third optical waveguide is configured to reach a side surface of the fifth clad layer.

9. The semiconductor device according to claim 1 , further comprising a lens portion optically connected with the second optical waveguide and formed on the upper surface of the third clad layer.

10. The semiconductor device according to claim 1 ,

wherein the first optical waveguide is composed of material including silicon, and

wherein the second optical waveguide is composed of material including resin.

11. The semiconductor device according to claim 1 ,

wherein a refractive index of the first optical waveguide is greater than a refractive index of the first clad layer and a refractive index of the second clad layer, and

wherein a refractive index of the second optical waveguide is greater than a refractive index of the third clad layer.

12. The semiconductor device according to claim 1 , wherein a thickness of the third clad layer is greater than a thickness of the second clad layer.

13. The semiconductor device according to claim 1 ,

wherein a recess portion is formed on the first resin portion,

wherein the recess portion is apart from the first optical waveguide, and

wherein a material including resin is buried in the recess portion.

14. The semiconductor device according to claim 1 , comprising a protective film formed on the first optical waveguide and the first clad layer,

wherein the protective film is exposed in the opening.

15. A manufacturing method of a semiconductor device comprising:

(a) preparing a substrate comprising a first clad layer, a first optical waveguide formed on the first clad layer, and a second clad layer formed on the first clad layer such that the second clad layer covers the first optical waveguide;

(b) forming an opening in the second clad layer, the opening overlapping an end portion of the first optical waveguide in plan view;

(c) supplying a first curable resin in the opening;

(d) pressing the first curable resin with a first pressing member to mold the first curable resin so as to be thicker as getting away from the end portion of the first optical waveguide;

(e) hardening the first curable resin by heat or light while the first curable resin is pressed with the first pressing member to form a first resin portion of a third clad layer;

(f) supplying a second curable resin on the first resin portion of the third clad layer;

(g) pressing the second curable resin with a second pressing member to adjust a thickness of the second curable resin so as to along a surface of the first resin portion of the third clad layer;

(h) hardening the second curable resin by heat or light while the second curable resin is pressed with the second pressing member;

(i) patterning the second curable resin hardened to form a second optical waveguide,

(j) supplying the opening with a third curable resin on the second optical waveguide and the first resin portion of the third clad layer in;

(k) pressing the third curable resin with a third pressing member to expose an end portion of the second optical waveguide from an upper surface of the third curable resin; and

(l) hardening the third curable resin by heat or light form a second resin portion of the third clad layer,

wherein the semiconductor device comprising:

the first clad layer;

the first optical waveguide formed on the first clad layer;

the second clad layer formed on the first optical waveguide and the first clad layer, the second clad layer having the opening overlapping the end portion of the first optical waveguide in plan view;

the second optical waveguide optically connected with the first optical waveguide and formed in the opening; and

the third clad layer burying the opening and configured to surround the second optical waveguide,

wherein the second optical waveguide is configured to reach an upper surface of the third clad layer from the end portion of the first optical waveguide, and

wherein the third clad layer comprises:

the first resin portion formed in the opening such that the second optical waveguide is formed on the first resin and composed of material including resin, and

the second resin portion formed on the first resin portion such that the second resin portion covers the second optical waveguide, the second resin portion composed of material including resin.

16. The manufacturing method of the semiconductor device according to claim 15 , wherein the first curable resin is molded so as to recess a surface of the first curable resin toward a first clad layer side.

17. The manufacturing method of the semiconductor device according to claim 15 , wherein the first curable resin is pressed so as to expose an upper surface of the end portion of the first optical waveguide in pressing the first curable resin.

18. The manufacturing method of the semiconductor device according to claim 15 , wherein the thickness of the second curable resin is adjusted so as to be smaller than the thickness of the second curable resin located in an upper portion of the opening in pressing the second curable resin.

19. The manufacturing method of the semiconductor device according to claim 15 , wherein the second optical waveguide is patterned such that a cross-sectional area of the second optical waveguide in a cross-sectional view perpendicular to an extending direction of the second optical waveguide increases as closing from one end portion of the second optical waveguide to the other end portion of the second optical waveguide in patterning the second curable resin hardened.

20. The manufacturing method of the semiconductor device according to claim 15 , further comprising:

(m) supplying a fourth curable resin on the and third clad layers;

(n) pressing the fourth curable resin with a fourth pressing member to expose the second optical waveguide;

(o) hardening the fourth curable resin by heat or light while the fourth curable resin is pressed with the fourth pressing member to form a fourth clad layer;

(p) supplying a fifth curable resin on the fourth clad layer;

(q) pressing the fifth curable resin with a fifth pressing member to adjust a thickness of the fifth curable resin so as to along a surface of the fourth clad layer;

(r) hardening the fifth curable resin by heat or light while the fifth curable resin is pressed with the fifth pressing member; and

(s) patterning the fifth curable resin hardened to form a third optical waveguide.

21. The manufacturing method of the semiconductor device according to claim 15 , further comprising:

(t) supplying a sixth curable resin in the opening, on the other end portion of the second optical waveguide and on the third clad layer;

(u) pressing the sixth curable resin with a sixth pressing member to mold the sixth curable resin located on the other end portion of the second optical waveguide into a lens shape; and

(v) hardening the sixth curable resin by heat or light while the sixth curable resin is pressed with the sixth pressing member.