Methods to make diffractive optical elements
View Patent ↗A method for forming a diffractive lens includes forming an etch stop layer on a first surface of a silicon substrate, forming a diffractive optical element above the etch stop layer, forming a planarization layer covering the diffractive optical element, planarizing the planarization layer, forming a bonding layer on the planarization layer, bonding a transparent substrate on the bonding layer, and etching a second surface of the silicon substrate to the etch stop layer to remove a portion of the silicon substrate opposite the diffractive optical element, wherein the remaining portion of the silicon substrate forms a bonding ring.
1. A method for forming a diffractive lens, comprising:
forming a stack comprising above a first surface of a transparent substrate, the stack comprising at least two phase shifting layers separated by an etch stop layer, the transparent substrate being transmissive to a light wavelength selected from infrared to ultraviolet;
patterning the stack to form layers of a diffractive optical element; and
bonding a bonding ring to the first surface of the transparent substrate around the diffractive optical element.
2. The method of claim 1 , wherein the transparent substrate comprises a material selected from the group consisting of quartz, Pyrex, and sapphire.
3. The method of claim 1 , wherein said forming a stack comprises:
(1) depositing a first phase shifting layer comprising a material selected from the group consisting of amorphous silicon and silicon nitride;
(2) growing the etch stop layer comprising silicon dioxide on the first phase shifting layer; and
(3) depositing a second phase shifting layer comprising the material on the etch stop layer.
4. The method of claim 1 , further comprising forming an opaque coating on a second surface of the substrate.
5. The method of claim 4 , wherein the opaque coating comprises amorphous silicon.
6. The method of claim 1 , further comprising, prior to said forming a stack:
forming an antireflective coating on the first surface of the transparent substrate, wherein the stack is formed on the antireflective coating.
7. The method of claim 1 , further comprising, subsequent to said patterning the stack:
forming an antireflective coating over the diffractive optical element.
8. The method of claim 1 , wherein said bonding comprises forming a bond selected from the group consisting of an anodic bond, an adhesive bond, a hydrofluoric acid bond, and a glass frit bond.
9. The method of claim 1 , further comprising bonding a submount to the bonding ring to form a package.
10. A method for forming a diffractive lens, comprising:
forming stack comprising above a first surface of a transparent substrate, the stack comprising at least two phase shifting layers separated by an etch stop layer, the transparent substrate being transmissive to a light wavelength selected from infrared to ultraviolet;
patterning the stack to form layers of a diffractive optical element; and
bonding a submount to the first surface of the transparent substrate with silicone.
11. A method for forming a diffractive lens, comprising:
providing a silicon-on-insulator (SOI) substrate comprising a transparent device layer, an insulator layer below the device layer, and a handle layer below the insulator layer, the transparent device layer being transmissive to a light wavelength selected from infrared to ultraviolet;
forming a stack above the transparent device layer, the stack comprising at least two phase shifting layers separated by an etch stop layer;
patterning the stack to form layers of a diffractive optical element; and
etching the handle layer to the insulator layer to remove a portion of the handle layer opposite the diffractive optical element, wherein the remaining portion of the handle layer forms a bonding ring.
12. The method of claim 11 , further comprising:
etching the insulator layer to remove a portion of the insulator layer opposite the diffractive optical element.
13. The method of claim 12 , further comprising:
forming an antireflective coating on a second surface of the transparent device layer opposite the diffractive optical element.
14. The method of claim 11 , further comprising:
forming a bonding pad on the bonding ring.
15. The method of claim 11 , further comprising:
forming a planarization layer over the diffractive optical element; and
planarizing the planarization layer.
16. The method of claim 15 , further comprising:
forming an antireflective layer on the planarization layer.
17. A diffractive lens, comprising:
a transparent substrate being transmissive to a light wavelength selected from infrared to ultraviolet;
a diffractive optical element above a first surface of the transparent substrate, the diffractive optical element comprising at least two phase shifting layers separated by an etch stop layer; and
a bonding ring bonded to the first surface of the transparent substrate around the diffractive optical element.
18. The lens of claim 17 , wherein the transparent substrate comprises a material selected from the group consisting of quartz, Pyrex, and sapphire.
19. The lens of claim 17 , further comprising an opaque coating on a second surface of the substrate.
20. The lens of claim 19 , wherein the opaque coating comprises amorphous silicon.
21. The lens of claim 17 , further comprising:
an antireflective coating between the first surface of the transparent substrate and the diffractive optical element.
22. The lens of claim 17 , further comprising:
an antireflective coating over the diffractive optical element.
23. The lens of claim 17 , wherein the bonding ring is bonded to the transparent substrate by a bond selected from the group consisting of an anodic bond, an adhesive bond, a hydrofluoric acid bond, and a glass frit bond.
24. The lens of claim 17 , further comprising:
a submount bonded to the bonding ring to form a package.
25. A diffractive lens, comprising:
a transparent substrate being transmissive to a light wavelength selected from infrared to ultraviolet;
a diffractive optical element above a first surface of the transparent substrate, the diffractive optical element comprising at least two phase shifting layers separated by an etch stop layer; and
a submount bonded to the first surface of the transparent substrate with silicone.
26. A diffractive lens, comprising:
a silicon-on-insulator (SOI) substrate comprising a transparent device layer, an insulator layer below the device layer, and a handle layer below the insulator layer, the transparent device layer being transmissive to a light wavelength selected from infrared to ultraviolet, the handle layer being etched so the remaining portion of the handle layer forms a bonding ring;
a diffractive optical element above a first surface of the transparent device layer, the diffractive optical element comprising at least two phase shifting layers separated by an etch stop layer.
27. The lens of claim 26 , further comprising:
an antireflective coating on a second surface of the transparent device layer opposite the diffractive optical element.
28. The lens of claim 26 , further comprising:
a bonding pad on the bonding ring.
29. The lens of claim 26 , further comprising:
a planarization layer over the diffractive optical element.
30. The lens of claim 29 , further comprising:
an antireflective layer over the planarization layer.
31. A method for forming a diffractive lens, comprising:
forming an etch stop layer on a first surface of a silicon substrate;
forming a diffractive optical element above the etch stop layer;
forming a planarization layer over the diffractive optical element;
planarizing the planarization layer;
bonding a transparent substrate to the planarization layer, the transparent substrate being transmissive to a light wavelength selected from infrared to ultraviolet; and
etching a second surface of the silicon substrate to the etch stop layer to remove at least a portion of the silicon substrate opposite the diffractive optical element.
32. The method of claim 31 , wherein the transparent substrate comprises a material selected from the group consisting of quartz, Pyrex, and sapphire.
33. The method of claim 31 , wherein said forming a diffractive optical element comprises:
forming a stack comprising at least two phase shifting layers separated by another etch stop layer; and
pattering the stack to form layers of the diffractive optical element.
34. The method of claim 31 , wherein said bonding a transparent substrate to the planarization layer comprises:
forming a bonding layer on the planarization layer; and
bonding the transparent substrate on the bonding layer by an anodic bond.
35. The method of claim 31 , further comprising, prior to said forming a diffractive optical element:
forming an antireflective layer on the etch stop layer, wherein the diffractive optical element is formed on the antireflective layer.
36. The method of claim 35 , further comprising:
etching the etch stop layer to remove a portion of the etch stop layer opposite the diffractive optical element.
37. The method of claim 31 , wherein the remaining portion of the silicon substrate forms a bonding ring.
38. The method of claim 37 , further comprising:
forming a bonding pad on the bonding ring.
39. The method of claim 37 , further comprising:
bonding a submount to the bonding ring to form a package.
40. The method of claim 31 , wherein said etching a second surface of the silicon substrate further comprises removing all of the silicon substrate.
41. A diffractive lens, comprising:
a transparent substrate being transmissive to a light wavelength selected from infrared to ultraviolet;
a planarization layer below the transparent substrate;
a diffractive optical element below the planarization layer; and
an etch stop layer below the diffractive optical element.
42. The diffractive lens of claim 41 , wherein the transparent substrate comprises a material selected from the group consisting of quartz, Pyrex, and sapphire.
43. The diffractive lens of claim 41 , wherein the diffractive optical element comprises at least two phase shifting layers separated by another etch stop layer.
44. The diffractive lens of claim 41 , further comprising:
a bonding layer between the transparent substrate and the planarization layer.
45. The diffractive lens of claim 41 , further comprising:
an antireflective layer between the etch stop layer and the diffractive optical element.
46. The diffractive lens of claim 41 , further comprising:
a bonding ring below the etch stop layer.
47. The diffractive lens of claim 46 , further comprising:
a bonding pad on the bonding ring.
48. The diffractive lens of claim 46 , further comprising:
a submount bonded to the bonding ring from a package.
49. A method for forming a diffractive lens, comprising:
forming a mold for a diffractive optical element on a first surface of a silicon substrate;
forming a lens layer above the mold, wherein the lens layer conforms to the mold to form the diffractive optical element, the lens layer being transmissive to a light wavelength selected from infrared to ultraviolet;
planarizing the lens layer;
bonding a transparent substrate to the lens layer; and
etching a second surface of the silicon substrate opposite of the diffractive optical element, wherein the remaining portion of the silicon substrate forms a bonding ring.
50. The method of claim 49 , further comprising, prior to said forming a lens layer above the mold:
forming an etch stop layer on the mold; and
wherein the lens layer is formed on the etch stop layer and said etching a second surface of the silicon substrate comprises etching the silicon substrate to the etch stop layer.
51. The method of claim 49 , wherein the lens layer comprises a material selected from the group consisting of silicon nitride and silicon dioxide.
52. The method of claim 49 , wherein the transparent substrate comprises a material selected from the group consisting of quartz, Pyrex, and sapphire.
53. The method of claim 49 , wherein said forming a mold comprises:
forming a stack comprising at least two lens layers separated by an etch stop layer; and
patterning the stack to form layers of the mold for the diffractive optical element.
54. The method of claim 49 , further comprising:
forming a bonding pad on the bonding ring.
55. The method of claim 49 , further comprising bonding a submount to the bonding ring to form a package.
56. A diffractive lens, comprising:
a transparent substrate being transmissive to a light wavelength selected from infrared to ultraviolet;
a diffractive optical element below the transparent substrate; and
a bonding ring below the diffractive optical element.
57. The diffractive lens of claim 56 , further comprising:
an etch stop layer between the diffractive optical element and the bond ring.
58. The diffractive lens of claim 56 , wherein the diffractive optical element comprises a material selected from the group consisting of silicon nitride and silicon dioxide.
59. The diffractive lens of claim 56 , wherein the transparent substrate comprises a material selected from the group consisting of quartz, Pyrex, and sapphire.
60. The diffractive lens of claim 56 , further comprising:
a bonding pad on the bonding ring.
61. The diffractive lens of claim 56 , further comprising:
a submount bonded to the bonding ring from a package.