What is claimed is:
1. A polarization separation device comprising:
a diffractive optical element layer formed out of an optically substantially isotropic transparent sheet and having a diffraction grating surface; and
an optically anisotropic layer formed out of an optically anisotropic birefringent material and disposed contiguously with the diffraction grating surface,
wherein the diffractive optical element layer is 0.1 to 1 mm thick.
2. A polarization separation device as claimed in claim 1,
wherein the diffractive optical element layer is made of a thermoplastic resin.
3. A polarization separation device as claimed in claim 1,
wherein the diffraction grating surface has a blazed grating, and fulfills conditional formulae (1), (2), and (3) or (4) below:
1.5<H<6(1) 0.1<n<0.3(2) npno(3) npne(4)
where
H represents a diffraction grating height (m);
n represents whichever refractive index difference npno or npne is greater;
np represents a refractive index of the diffractive optical element layer;
no represents a refractive index for ordinary light of the optically anisotropic layer; and
ne represents a refractive index for extraordinary light of the optically anisotropic layer.
4. A polarization separation device as claimed in claim 1, further comprising:
a transparent substrate disposed contiguously with the optically anisotropic layer in such a way that the optically anisotropic layer is sandwiched between the transparent substrate and the diffractive optical element layer,
wherein the optically anisotropic layer is made of nematic or smectic liquid crystal, and
wherein, on a surface of the transparent substrate that faces the optically anisotropic layer, an orientation film is provided that has been subjected to a rubbing process so that molecules of the liquid crystal are oriented homogeneously along grooves of the diffraction grating surface.
5. A polarization separation device as claimed in claim 4,
wherein the transparent substrate and the diffractive optical element layer have substantially equal linear expansion coefficients.
6. A polarization separation device comprising:
a first transparent flat plate;
a second transparent flat plate;
a diffractive optical element disposed between the first and second transparent flat plates and formed as a thin sheet or film of an optically substantially isotropic transparent resin; and
liquid crystal sealed in between the first and second transparent flat plates,
wherein the diffractive optical element has a flat surface on a side thereof facing the first transparent flat plate and has a blazed diffraction grating surface on a side thereof facing the second transparent flat plate,
wherein, with the first and second transparent flat plates firmly fitted together with sealant, the liquid crystal is sealed in between the first and second transparent flat plates so as to be contiguous with the diffraction grating surface, and
wherein a surface of the second transparent flat plate that faces the diffractive optical element has been subjected to an orientation process.
7. A polarization separation device as claimed in claim 6,
wherein the diffractive optical element is, at the flat surface thereof, bonded to the first transparent flat plate.
8. A polarization separation device as claimed in claim 6,
wherein the diffractive optical element and the first and second transparent flat plates are firmly fitted together with the sealant.
9. A polarization separation device as claimed in claim 6,
wherein the diffractive optical element is made of a thermoplastic resin.
10. A polarization separation device as claimed in claim 6,
wherein, on a surface of the first or second transparent flat plate that faces away from the diffractive optical element, a first lens array having a plurality of lens cells with which to separate incident light is formed as part of an integrator.
11. A polarization separation device comprising:
a first transparent flat plate;
a second transparent flat plate;
a diffractive optical element disposed between the first and second transparent flat plates and formed as a thin sheet or film of an optically substantially isotropic transparent resin; and
liquid crystal sealed in between the first and second transparent flat plates,
wherein the diffractive optical element has blazed diffraction grating surfaces on both sides thereof facing the first and second transparent flat plates,
wherein, with the first and second transparent flat plates firmly fitted together with sealant, the liquid crystal is sealed in between the first and second transparent flat plates so as to be contiguous with the diffraction grating surface, and
wherein surfaces of the first and second transparent flat plates that face the diffractive optical element have been subjected to an orientation process.
12. A polarization separation device as claimed in claim 11,
wherein the diffractive optical element and the first and second transparent flat plates are firmly fitted together with the sealant.
13. A polarization separation device as claimed in claim 11,
wherein the diffractive optical element is made of a thermoplastic resin.
14. A polarization separation device as claimed in claim 11,
wherein, on a surface of the first or second transparent flat plate that faces away from the diffractive optical element, a first lens array having a plurality of lens cells with which to separate incident light is formed as part of an integrator.
15. An illumination optical system comprising:
a light source for emitting illumination light;
an integrator rod for making spatial energy distribution of the illumination light emitted from the light source uniform;
a polarization separation device as claimed in claim 6 for separating the illumination light that has exited from the integrator rod into two linearly polarized light components having mutually perpendicular polarization planes;
a relay lens for relaying the two linearly polarized light components separated by the polarization separation device; and
polarization plane rotating means for rotating the polarization plane of one of the two linearly polarized light components through about 90 in vicinity of an aperture stop position of the relay lens, or in vicinity of a position conjugate therewith, so as to make polarization of light that exits from the relay lens uniform.
16. An illumination optical system as claimed in claim 15,
wherein the diffraction grating surface fulfills conditional formulae (1), (2), and (3) or (4) below:
1.5<H<6(1) 0.1<n<0.3(2) npno(3) npne(4)
where
H represents a diffraction grating height (m);
n represents whichever refractive index difference npno or npne is greater;
np represents a refractive index of the diffractive optical element;
no represents a refractive index for ordinary light of the liquid crystal; and
ne represents a refractive index for extraordinary light of the liquid crystal.
17. An illumination optical system as claimed in claim 15, wherein the diffraction grating surface fulfills conditional formula (5) below:
5<D<15(5)
where
D represents a diffraction grating pitch (m).
18. An illumination optical system as claimed in claim 15, further comprising:
a UVIR cut filter disposed between the light source and the polarization separation device.
19. An illumination optical system as claimed in claim 15,
wherein the polarization plane rotating means is a half-wave plate.
20. An illumination optical system comprising:
a light source for emitting illumination light;
an integrator rod for making spatial energy distribution of the illumination light emitted from the light source uniform;
a polarization separation device as claimed in claim 11 for separating the illumination light that has exited from the integrator rod into two linearly polarized light components having mutually perpendicular polarization planes;
a relay lens for relaying the two linearly polarized light components separated by the polarization separation device; and
polarization plane rotating means for rotating the polarization plane of one of the two linearly polarized light components through about 90 in vicinity of an aperture stop position of the relay lens, or in vicinity of a position conjugate therewith, so as to make polarization of light that exits from the relay lens uniform.
21. An illumination optical system as claimed in claim 20,
wherein the diffraction grating surface fulfills conditional formulae (1), (2), and (3) or (4) below:
1.5<H<6(1) 0.1<n<0.3(2) npno(3) npne(4)
where
H represents a diffraction grating height (m);
n represents whichever refractive index difference npno or npne is greater;
np represents a refractive index of the diffractive optical element;
no represents a refractive index for ordinary light of the liquid crystal; and
ne represents a refractive index for extraordinary light of the liquid crystal.
22. An illumination optical system as claimed in claim 20, wherein the diffraction grating surface fulfills conditional formula (5) below:
5<D<15(5)
where
D represents a diffraction grating pitch (m).
23. An illumination optical system as claimed in claim 20, further comprising:
a UVIR cut filter disposed between the light source and the polarization separation device.
24. An illumination optical system as claimed in claim 20,
wherein the polarization plane rotating means is a half-wave plate.
25. An illumination optical system comprising:
a light source for emitting illumination light;
a first lens array and a second lens array for making spatial energy distribution of the illumination light emitted from the light source uniform;
a polarization separation device as claimed in claim 6 for separating the illumination light into two linearly polarized light components having mutually perpendicular polarization planes in vicinity of the first lens array; and
polarization plane rotating means for rotating the polarization plane of one of the two linearly polarized light components through about 90 in vicinity of the second lens array, or in vicinity of a position conjugate therewith, so as to make polarization of light that exits from the second lens array uniform.
26. An illumination optical system as claimed in claim 25,
wherein the diffraction grating surface fulfills conditional formulae (1), (2), and (3) or (4) below:
1.5<H<6(1) 0.1<n<0.3(2) npno(3) npne(4)
where
H represents a diffraction grating height (m);
n represents whichever refractive index difference npno or npne is greater;
np represents a refractive index of the diffractive optical element;
no represents a refractive index for ordinary light of the liquid crystal; and
ne represents a refractive index for extraordinary light of the liquid crystal.
27. An illumination optical system as claimed in claim 25,
wherein the diffraction grating surface fulfills conditional formula (5) below:
5<D<15(5)
where
D represents a diffraction grating pitch (m).
28. An illumination optical system as claimed in claim 25, further comprising:
a UVIR cut filter disposed between the light source and the polarization separation device.
29. An illumination optical system as claimed in claim 25,
wherein the polarization plane rotating means is a half-wave plate.
30. An illumination optical system comprising:
a light source for emitting illumination light;
a first lens array and a second lens array for making spatial energy distribution of the illumination light emitted from the light source uniform;
a polarization separation device as claimed in claim 11 for separating the illumination light into two linearly polarized light components having mutually perpendicular polarization planes in vicinity of the first lens array; and
polarization plane rotating means for rotating the polarization plane of one of the two linearly polarized light components through about 90 in vicinity of the second lens array, or in vicinity of a position conjugate therewith, so as to make polarization of light that exits from the second lens array uniform.
31. An illumination optical system as claimed in claim 30, wherein the diffraction grating surface fulfills conditional formulae (1), (2), and (3) or (4) below:
1.5<H<6(1) 0.1<n<0.3(2) npno(3) npne(4)
where
H represents a diffraction grating height (m);
n represents whichever refractive index difference npno or npne is greater;
np represents a refractive index of the diffractive optical element;
no represents a refractive index for ordinary light of the liquid crystal; and
ne represents a refractive index for extraordinary light of the liquid crystal.
32. An illumination optical system as claimed in claim 30,
wherein the diffraction grating surface fulfills conditional formula (5) below:
5<D<15(5)
where
D represents a diffraction grating pitch (m).
33. An illumination optical system as claimed in claim 30, further comprising:
a UVIR cut filter disposed between the light source and the polarization separation device.
34. An illumination optical system as claimed in claim 30,
wherein the polarization plane rotating means is a half-wave plate.
35. A blazed grating device comprising:
a plate-shaped transparent substrate having a blazed grating formed on a surface thereof; and
a separation coating formed on the blazed grating of the transparent substrate so as to reflect or transmit incident light according to properties of the incident light.
36. A blazed grating device as claimed in claim 35, further comprising:
a plate-shaped transparent member kept in intimate contact with the blazed grating of the transparent substrate with the separation coating sandwiched in between.
37. A blazed grating device as claimed in claim 36, further comprising:
a blazed grating formed on a surface of the transparent member that faces away from the transparent substrate;
a separation coating formed on the blazed grating of the transparent member so as to reflect or transmit incident light according to properties of the incident light; and
a plate-shaped transparent member kept in intimate contact with the blazed grating of the transparent member with the separation coating sandwiched in between.
38. A blazed grating device as claimed in claim 35,
wherein the separation coating reflects or transmits the incident light according to how the incident light is polarized.
39. A blazed grating device as claimed in claim 35,
wherein the separation coating reflects or transmits the incident light according to a wavelength of the incident light.
40. A blazed grating device as claimed in claim 35,
wherein the separation coating reflects or transmits the incident light according to an angle of incidence of the incident light.
41. A diffraction grating device comprising:
a plate-shaped transparent substrate having a diffraction grating formed on a surface thereof;
a separation coating formed on the diffraction grating of the transparent substrate so as to reflect or transmit incident light according to how the incident light is polarized; and
a plate-shaped transparent member kept in intimate contact with the diffraction grating of the transparent substrate with the separation coating sandwiched in between.
42. A diffraction grating device as claimed in claim 41,
wherein light reflected from the separation coating is totally reflected inside the transparent substrate and is thereby directed to an end surface of the transparent substrate.
43. An illumination optical system comprising:
a diffraction grating device comprising:
a plate-shaped transparent substrate having a diffraction grating formed on a surface thereof, and
a separation coating formed on the diffraction grating of the transparent substrate so as to reflect or transmit incident light according to properties of the incident light,
wherein the illumination optical system uses the diffraction grating device both to direct light to an object to be illuminated so a s to illuminate the object and to direct light reflected from the object out of the illumination optical system by letting this light pass through the diffraction grating.
44. An illumination optical system as claimed in claim 43,
wherein the diffraction grating device further comprises:
a plate-shaped transparent member kept in intimate contact with the diffraction grating of the transparent substrate with the separation coating sandwiched in between.
45. An illumination optical system as claimed in claim 43,
wherein the separation coating reflects or transmits the incident light according to an angle of incidence of the incident light.
46. An illumination optical system as claimed in claim 43,
wherein the separation coating is a chiral nematic liquid crystal layer that reflects one and transmits another of two circularly polarized light components having different rotation directions.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method for planarizing a surface of a photoresist layer on a substrate of a wafer, comprising:
positioning over a starting surface of the photoresist layer a gray-scale mask having a pattern that correlates with a gradient height profile of unevenness present on the starting surface;
patterning the photoresist layer by using the gray-scale mask to produce the pattern of the gray-scale mask in the photoresist layer which, in effect, produces a patterned profile of evenness in the photoresist layer underlying the gradient height profile of unevenness;
and developing the patterned photoresist layer such that a three-dimensional portion thereof corresponding to the gradient height profile of unevenness located above the patterned profile of evenness is removed which, in effect, leaves behind a resulting surface of the photoresist layer made substantially more even and thus substantially in a planarized condition, said patterning further including overexposing a marginal edge portion of the photoresist layer to create a negative step into the resulting surface and an outer edge on the photoresist layer extending around the wafer.
2. The method of claim 1 wherein said patterning produces the patterned profile of evenness in the photoresist layer by exposing the photoresist layer with a predetermined light that is modulated in intensity as it passes through the pattern of the gray-scale mask.
3. The method of claim 2 wherein said exposing the photoresist layer with the predetermined light renders it susceptible to the subsequent developing thereof by the predetermined light penetrating the photoresist layer to variable depths in the photoresist layer correlated with the modulated intensity of the light, from the starting surface thereon, as defined by the gradient height profile of unevenness correlated with the pattern of the gray-scale mask, to the patterned profile of evenness produced in the photoresist layer by the modulated intensity of the light passing through the gray-scale mask.
4. The method of claim 1 wherein said patterning includes transmitting predetermined light through the pattern of the gray-scale mask to thereby control the intensity of the light penetrating the photoresist layer and thereby the variable depths in the photoresist layer.
5. The method of claim 4 wherein said patterning further includes controlling the duration of time that the light is transmitted through the pattern of the gray-scale mask.
6. A method for removing a peripheral edge bead on a surface of a photoresist layer on a substrate of a wafer, comprising:
positioning over a starting surface of the photoresist layer having the peripheral edge bead present thereon a gray-scale mask having a profile that correlates with a gradient height profile of unevenness on the starting surface due to the presence of the peripheral edge bead thereon;
patterning the photoresist layer by using the gray-scale mask to produce the pattern of the gray-scale mask in the photoresist layer which, in effect, produces a patterned profile of evenness in the photoresist layer underlying the gradient height profile of unevenness;
and developing the patterned photoresist layer such that the peripheral edge bead corresponding to the gradient height profile of unevenness located above the patterned profile of evenness is removed which, in effect, leaves behind a resulting surface on the photoresist layer substantially without the presence of the peripheral edge bead thereon and thereby made substantially more even and thus substantially in a planarized condition. said patterning further including overexposing a marginal edge portion of the photoresist layer to create a negative step into the resulting surface and an outer edge on the photoresist layer extending around the wafer.
7. The method of claim 6 wherein said patterning produces the patterned profile of evenness in the photoresist layer by exposing the photoresist layer with a predetermined light that is modulated in intensity as it passes through the gray-scale mask.
8. The method of claim 7 wherein said exposing the photoresist layer with the predetermined light renders it susceptible to the subsequent developing thereof due to the predetermined light penetrating the photoresist layer to variable depths in the photoresist layer from the starting surface thereon, as defined by the gradient height profile of unevenness correlated with the pattern of the gray-scale mask and thereby, to the patterned profile of evenness produced in the photoresist layer by the gray-scale mask.
9. The method of claim 8 wherein said patterning also includes transmitting the predetermined light through the pattern of the gray-scale mask to thereby control the intensity of the predetermined light penetrating the photoresist layer and thereby the variable depths in the photoresist layer.
10. The method of claim 9 wherein said patterning further includes controlling the duration of time that the predetermined light is transmitted through the pattern of the gray-scale mask.