High Contrast Inverse Polarizer

1 . An embedded, inverse wire-grid polarizer (WGP) comprising ribs located over a surface of a transparent substrate, gaps between the ribs, and a fill-layer substantially filling the gaps, wherein:

a. the ribs are elongated and formed into an array;

b. at a wavelength of light incident upon the WGP, E 195 transmission>E ⊥ transmission, where:

i. E ∥ is a polarization of the light with an electric field oscillation parallel to a length of the ribs; and

ii. E ⊥ is a polarization of the light with an electric field oscillation perpendicular to a length of the ribs; and

c. the fill-layer has an index of refraction greater than 1.4 at the wavelength of the light.

2 . The embedded, inverse WGP of claim 1 , wherein P*(n-0.2)<λ<P*(n+0.2), where:

a. λ is the wavelength of the light;

b. P is a pitch of the ribs; and

c. n is the index of refraction of the fill-layer.

3 . The embedded, inverse WGP of claim 1 , wherein the fill-layer substantially fills the gaps and extends from the gaps over the ribs such that the fill-layer in each gap extends continuously over adjacent ribs to the fill-layer in each adjacent gap.

4 . The embedded, inverse WGP of claim 3 , wherein the fill-layer extends over the ribs for a thickness of between 50 and 100 nanometers.

5 . The embedded, inverse WGP of claim 1 , wherein, at the wavelength of the light, the E ∥ transmission divided by the E 195 transmission is at least 1000.

6 . The embedded, inverse WGP of claim 1 , wherein:

a. the wavelength of the light is less than 400 nanometers; and

b. the E ∥ transmission divided by the E ⊥ transmission is at least 300.

7 . The embedded, inverse WGP of claim 6 , wherein:

a. the wavelength of the light is less than 400 nanometers; and

b. a pitch of the ribs is greater than 140 nanometers.

8 . The embedded, inverse WGP of claim 6 , wherein a width of the ribs divided by a pitch of the ribs is between 0.45 and 0.65.

9 . The embedded, inverse WGP of claim 1 , wherein:

a. a width of the ribs divided by a pitch of the ribs is less than 0.7;

b. the wavelength of the light is less than 400 nanometers;

c. for a wavelength range of light of at least 30 nanometers, that includes the wavelength of the light, E ∥ transmission is greater than 80%; and

d. the E ∥ transmission divided by the E 195 transmission is at least 10.

10 . The embedded, inverse WGP of claim 1 , wherein the wavelength of the light divided by a pitch of the ribs is less than 2.

11 . The embedded, inverse WGP of claim 1 , wherein the index of refraction of the fill-layer is greater than 1.5.

12 . The embedded, inverse WGP of claim 1 , wherein the fill-layer is transparent.

13 . The embedded, inverse WGP of claim 1 , wherein:

a. a difference between a lower-rib-width and an upper-rib-width is greater than 20 nanometers, where:

i. lower-rib-width means a maximum width of the ribs in a lower-half of the rib closer to the substrate; and

ii. upper-rib-width means a maximum width of the ribs in an upper-half of the rib farther from the substrate; and

b. for a wavelength range of light of at least 20 nanometers in the ultraviolet spectrum, the E ∥ transmission divided by the E ⊥ transmission is at least 300.

14 . The embedded, inverse WGP of claim 1 , wherein:

a. a cross-sectional-profile of the ribs includes a rounded shape; and

b. for a wavelength of light in the ultraviolet spectrum, the E ∥ transmission divided by the E ⊥ transmission is at least 300.

15 . The embedded, inverse WGP of claim 1 , wherein the WGP forms part of an integrated circuit (IC) inspection tool, the IC inspection tool comprising:

a. an ultraviolet light source;

b. a stage for holding an IC wafer;

c. the ultraviolet light source located to emit an incident ultraviolet light-beam onto the IC wafer;

d. a detector located to receive an output light-beam from the IC wafer;

e. an electronic circuit configured to receive and analyze a signal from the detector, the signal based on the output light-beam received by the detector; and

f. the WGP located in a path of the incident light-beam, a path of the output light-beam, or both.

16 . The embedded, inverse WGP of claim 1 , wherein the WGP forms part of a flat panel display (FPD) manufacturing tool, the FPD manufacturing tool comprising:

a. a light source capable of emitting ultraviolet light;

b. a stage for holding an FPD; and

c. the WGP, located between the light source and the stage, and configured to polarize the ultraviolet light with E ∥ transmission>E 195 transmission.

17 . A method of polarizing light, the method comprising:

a. providing an inverse wire-grid polarizer (WGP) comprising an array of elongated ribs located over a surface of a transparent substrate, gaps between at least a portion of the ribs, and a fill-layer filling the gaps between the adjacent ribs; and

b. transmitting more E ∥ through the WGP than E ⊥ , where:

i. E ∥ is a polarization of the light with an electric field oscillation parallel to a length of the ribs; and

ii. E 195 is a polarization of the light with an electric field oscillation perpendicular to a length of the ribs.

18 . The method of claim 17 , wherein, at a wavelength in the ultraviolet spectrum, the E ∥ transmission divided by the E ⊥ transmission is at least 300.

19 . A method of designing an embedded, inverse wire-grid polarizer (WGP), the method comprising:

a. calculating a pitch of an array of ribs of the WGP for E ∥ transmission>E 195 transmission at a desired wavelength, where:

i. E ∥ is a polarization of the light with an electric field oscillation parallel to a length of the ribs; and

ii. E ⊥ is a polarization of the light with an electric field oscillation perpendicular to a length of the ribs; and

b. calculating an index of refraction of a fill-layer, located over the array of ribs and substantially filling gaps between the ribs, for E ∥ transmission>E ⊥ transmission at the desired wavelength.

20 . The method of claim 19 , further comprising selecting at least two of the following to increase E ∥ transmission divided by E ⊥ transmission at the desired wavelength: rib material, rib thickness, rib shape, rib width divided by rib pitch, substrate material, and thickness of the fill-layer over the array of ribs.