Multi stack optical elements using temporary and permanent bonding
Systems and methods herein are related to the formation of optical devices including stacked optical element layers using silicon wafers, glass, or devices as substrates. The optical elements discussed herein can be fabricated on temporary or permanent substrates. In some examples, the optical devices are fabricated to include transparent substrates or devices including charge-coupled devices (CCD), or complementary metal-oxide semiconductor (CMOS) image sensors, light-emitting diodes (LED), a micro-LED (uLED) display, organic light-emitting diode (OLED) or vertical-cavity surface-emitting laser (VCSELs). The optical elements can have interlayers formed in between optical element layers, where the interlayers can range in thickness from 1 nm to 3 mm.
1. A method of forming an optical device, comprising:
(a) forming a pattern in a target layer on a first substrate, wherein the pattern comprises a plurality of islands separated by a plurality of trenches;
(b) forming a fill layer on top of the patterned target layer and in the plurality of trenches formed in the patterned target layer to form a first optical element layer; and
(c) forming an optical element layer stack on the first optical element layer by repeating (a) and (b) for a plurality of iterations.
2. The method of claim 1 , further comprising (d), subsequent to (c), bonding a second substrate to the optical element layer stack opposite the first substrate.
3. The method of claim 2 , further comprising (e), removing, subsequent to (d), the first substrate.
4. The method of claim 1 , wherein the fill layer includes an interlayer, wherein the interlayer extends from a top surface of the target layer for a thickness of about 50 nm to about 50 microns.
5. The method of claim 1 , wherein the first substrate comprises a CCD, a CMOS sensor, a VCSEL, or an LED.
6. The method of claim 1 , further comprising:
(f) subsequent to (a), forming an optical element layer on top of the target layer and in the plurality of trenches of the patterned target layer;
(g) removing a portion of the optical element layer, wherein removing the portion creates a co-planar surface of the optical element layer and a top surface of the target layer;
(h) subsequent to (g), forming a second fill layer on top of the optical element layer and the target layer to form a first optical element layer, wherein a the second fill layer includes an interlayer extending beyond a top surface of the optical element layer for a distance from 0.5 microns to 50 microns; and
(i) repeating (a)-(h) to form a plurality of optical element layers on the first optical element layer.
7. The method of claim 6 , wherein the optical element layer comprises a-Si, SiN, TiO 2 , or GaP.
8. A method of fabricating optical devices, comprising:
forming a first pattern in a first target layer, the first target layer being formed on a first substrate;
forming a second pattern in a second target layer formed on a second substrate;
bonding the first pattern to a first side of a third substrate, the third substrate being formed from a transparent material and being from about 10 μm thick to 3 mm thick;
bonding the second pattern to a second side of the third substrate;
de-bonding the first substrate from the first pattern; and
de-bonding the second substrate from the second pattern.
9. The method of claim 8 , wherein the first pattern is formed using nanoimprint lithography (NIL) and etching.
10. The method of claim 8 , wherein the first pattern is formed using optical lithography and etching.
11. The method of claim 8 , wherein forming the first pattern comprises directly imprinting the first target layer using a first pattern master.
12. The method of claim 8 , further comprising filling at least one of the first pattern or the second pattern with a low-index material.
13. The method of claim 8 , further comprising:
forming a third pattern in a third target material on a fourth substrate.
14. The method of claim 13 , further comprising:
bonding a first side of a fifth substrate to the second pattern, the fifth substrate being from about 10 μm thick to about 3 mm thick and formed from a transparent material; and
bonding the third pattern to a second side of the fifth substrate.
15. The method of claim 8 , wherein each of forming the first pattern and forming the second pattern comprises optical lithography or nanoimprint lithography.
16. A method of forming an optical device, comprising:
forming a first pattern by imprinting a first target layer in a first location using a first pattern master, the first target layer being formed on a first side of a transparent substrate, wherein the transparent substrate is from about 10 μm thick to about 3 mm thick; and
forming a second pattern by imprinting a second pattern in a second location on a second target layer formed on a second side of the transparent substrate using a second pattern master, wherein forming the second pattern in the second location comprises determining the second location relative to the first pattern and aligning the second pattern master in the second location.
17. The method of claim 16 , wherein the first pattern master is formed from silicon.
18. The method of claim 16 , further comprising, subsequent to forming the first pattern, filling the first pattern with a low-index material.
19. The method of claim 16 , wherein the first master pattern includes a first pattern and the second pattern master includes a second pattern, the first pattern being different from the second pattern.
20. The method of claim 16 , wherein the transparent substrate is formed from glass, polymer, or diamond.