Fabrication of liquid crystal-based electro-optic light modulators using surface MEMS technology for flat panel display testing

Abstract

An electro-optic modulator is a liquid crystal-based electro-optic light modulator. Liquid crystal-based electro-optic light modulators are fabricated using surface micro-electro-mechanical systems (MEMS) technology. Electro-optic light modulators are used in testing flat panel displays and the like. Utilizing surface MEMS technology for fabrication allows electro-optic modulators to be significantly thinner, enabling the use of pure liquid crystals without the need for thick containment plates.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit under 35 U.S.C. §119(e) of U.S. Provisional Application No. 63 / 406,712, filed September 14, 2022, entitled "METHOD FOR FABRICATING A LIQUID-CRYSTAL-BASED ELECTRO-OPTICAL LIGHT MODULATOR USING SURFACE MEMS TECHNIQUES FOR INSPECTION FLAT PANEL DISPLAYS," which is incorporated herein by reference in its entirety.

[0002] The present invention relates generally to electro-optics, and more particularly to liquid crystal materials used in electro-optic applications. [Background technology]

[0003] Electro-optic modulators that use liquid crystals for modulation, specifically nematic curvilinearly aligned phase (NCAP) or polymer dispersed liquid crystal (PDLC) films, are used to test thin film transistor continuity and flat panel display (FPD) interconnects during fabrication. Electro-optic modulators are mechanically fabricated using a thick stack of subcomponents: adhesives, NCAP films on Mylar™, pellicle dielectric mirrors, and hard coats. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] U.S. Patent Application Publication No. 2015 / 261024 Summary of the Invention [Problem to be solved by the invention]

[0005] Electro-optic modulators are prone to a high degree of variation and degradation in performance resulting in increased noise, reduced dynamic range, and reduced sensitivity. For example, NCAP films having thicknesses of 12 microns or 25 microns have a thickness variation of 20%. Therefore, it would be advantageous to provide devices, systems, and methods that address the above-mentioned shortcomings. [Means for solving the problem]

[0006] An electro-optical modulator is described according to one or more embodiments of the present disclosure. The electro-optical modulator includes a glass substrate. The electro-optical modulator includes a transparent electrode disposed on the glass substrate. The electro-optical modulator includes a first alignment layer disposed on the transparent electrode. The electro-optical modulator includes a liquid crystal layer disposed on the first alignment layer. The electro-optical modulator includes a second alignment layer disposed on the liquid crystal layer. The electro-optical modulator includes a polymer layer disposed on the second alignment layer. The electro-optical modulator includes a plurality of polymer studs. The plurality of polymer studs extend through at least a portion of the liquid crystal layer. The plurality of polymer studs mechanically support the polymer layer. The electro-optical modulator includes a dielectric mirror disposed on the polymer layer. The electro-optical modulator includes a hard coat layer disposed on the dielectric mirror.

[0007] In some embodiments, the liquid crystal layer has a thickness of 2 to 5 micrometers.

[0008] In some embodiments, the liquid crystal layer is neither a nematic curvilinearly aligned phase nor a polymer dispersed liquid crystal.

[0009] In some embodiments, the plurality of polymer studs extend from the polymer layer through the second alignment layer and at least a portion of the liquid crystal layer.

[0010] In some embodiments, the electro-optic modulator includes a plurality of alignment studs, the plurality of alignment studs extending from the second alignment layer to the first alignment layer, the plurality of polymer studs extending through at least a portion of the liquid crystal layer to the alignment studs, and the plurality of polymer studs disposed on the plurality of alignment studs.

[0011] In some embodiments, the electro-optic modulator includes an anti-reflective coating, and the glass substrate is disposed over the anti-reflective coating.

[0012] In some embodiments, the plurality of polymer studs extend from the second alignment layer through the liquid crystal layer to the first alignment layer, the plurality of polymer studs being separated from the polymer layer by the second alignment layer.

[0013] In some embodiments, each of the plurality of polymer studs has a width of less than 1.4 micrometers and a thickness of 2 to 5 micrometers.

[0014] In some embodiments, each of the plurality of polymeric studs has a sidewall angle of between 83 and 93 degrees.

[0015] In some embodiments, the transparent electrode comprises at least one of indium tin oxide (ITO) or silver nanowires.

[0016] In some embodiments, the first and second alignment layers each comprise at least one of silicon oxynitride or silicon dioxide.

[0017] In some embodiments, the first alignment layer and the second alignment layer each have a refractive index between 1.51 and 1.55.

[0018] In some embodiments, the polymer layer and the plurality of polymer studs each comprise a cross-linked polymer.

[0019] In some embodiments, the dielectric mirror has a reflectivity of greater than 80% for light with wavelengths between 570 and 670 nm.

[0020] In some embodiments, the dielectric mirror is a stack of alternating layers of silicon nitride and silicon dioxide.

[0021] In some embodiments, the dielectric mirror is a stack of alternating layers of zirconium oxide and silicon dioxide.

[0022] In some embodiments, the electro-optic modulator includes an epoxy seal that seals the liquid crystal layer between the first alignment layer and the second alignment layer.

[0023] An imaging system is described according to one or more embodiments of the present disclosure. The imaging system includes an illumination light source configured to generate illumination. The imaging system includes a stage for a sample. The imaging system includes a detector for generating an image of at least a portion of the sample. The imaging system includes an electro-optic modulator disposed in a path of illumination from the illumination light source and separated from the sample by an air gap. The electro-optic modulator includes a glass substrate. The electro-optic modulator includes transparent electrodes disposed on the glass substrate. The electro-optic modulator includes a first alignment layer disposed on the transparent electrodes. The electro-optic modulator includes a liquid crystal layer disposed on the first alignment layer. The electro-optic modulator includes a second alignment layer disposed on the liquid crystal layer. The electro-optic modulator includes a polymer layer disposed on the second alignment layer. The electro-optic modulator includes a plurality of polymer studs. The plurality of polymer studs extend through at least a portion of the liquid crystal layer. The plurality of polymer studs mechanically support the polymer layer. The electro-optic modulator includes a dielectric mirror disposed on the polymer layer. The electro-optic modulator includes a hard coat layer disposed on the dielectric mirror.

[0024] An electro-optical modulator is described according to one or more embodiments of the present disclosure. The electro-optical modulator includes a glass substrate. The electro-optical modulator includes a transparent electrode disposed on the glass substrate. The electro-optical modulator includes a first alignment layer disposed on the transparent electrode. The electro-optical modulator includes a liquid crystal layer disposed on the first alignment layer. The electro-optical modulator includes a second alignment layer disposed on the liquid crystal layer. The electro-optical modulator includes a plurality of alignment studs. The plurality of alignment studs extend from the second alignment layer through the liquid crystal layer to the first alignment layer. The electro-optical modulator includes a dielectric mirror disposed on the second alignment layer. The electro-optical modulator includes a plurality of dielectric studs. The plurality of dielectric studs extend from the dielectric mirror through a first portion of the liquid crystal layer to the plurality of alignment studs. The plurality of dielectric studs are disposed on the plurality of alignment studs. The electro-optical modulator includes a polymer layer disposed on the dielectric mirror. The electro-optical modulator includes a plurality of polymer studs. The plurality of polymer studs extend from the polymer layer, through the dielectric mirror, the second alignment layer, and the second portion of the liquid crystal layer, to the plurality of dielectric studs. The plurality of polymer studs are disposed on the plurality of dielectric studs.

[0025] In some embodiments, the liquid crystal layer has a thickness of 2 to 5 micrometers.

[0026] In some embodiments, the liquid crystal layer is neither a nematic curvilinearly aligned phase nor a polymer dispersed liquid crystal.

[0027] The many advantages of the present disclosure may be better understood by those skilled in the art by reference to the accompanying drawings. [Brief explanation of the drawings]

[0028] [Figure 1A] 1 illustrates a cross-sectional view of an electro-optic modulator according to one or more embodiments of the present disclosure. [Figure 1B] 1 illustrates a top view of a liquid crystal layer, polymer studs, alignment studs, and an epoxy seal of an electro-optic modulator in accordance with one or more embodiments of the present disclosure. [Figure 2A]1 shows a flow diagram of a method for fabricating an electro-optic modulator according to one or more embodiments of the present disclosure. [Figure 2B] 1 shows a flow diagram of a method for fabricating an electro-optic modulator according to one or more embodiments of the present disclosure. [Figure 2C] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 2D] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 2E] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 2F] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 2G] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 2H] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 2I] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 2J] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 2K] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 2L] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 2M] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 2N] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 3] 1 illustrates a cross-sectional view of an electro-optic modulator according to one or more embodiments of the present disclosure. [Figure 4A]1 shows a flow diagram of a method for fabricating an electro-optic modulator according to one or more embodiments of the present disclosure. [Figure 4B] 1 shows a flow diagram of a method for fabricating an electro-optic modulator according to one or more embodiments of the present disclosure. [Figure 4C] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 4D] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 4E] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 4F] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 4G] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 4H] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 4I] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 4J] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 4K] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 4L] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 4M] 1A-1C illustrate cross-sectional views of an electro-optic modulator during a method in accordance with one or more embodiments of the present disclosure. [Figure 5] 1 illustrates a cross-sectional view of an electro-optic modulator according to one or more embodiments of the present disclosure. [Figure 6] 1 shows a simplified diagram of an imaging system in accordance with one or more embodiments of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present disclosure has been particularly shown and described with respect to certain embodiments and specific features thereof. The embodiments described herein are to be considered illustrative and not limiting. It will be readily apparent to those skilled in the art that various changes and modifications in form and detail can be made therein without departing from the spirit and scope of the present disclosure. Reference will now be made in detail to the disclosed subject matter, which is illustrated in the accompanying drawings.

[0030] Embodiments of the present disclosure generally relate to electro-optic modulators, methods for fabricating electro-optic modulators, and imaging systems that use electro-optic modulators. The electro-optic modulators are liquid crystal-based electro-optic light modulators. The liquid crystal-based electro-optic light modulators are fabricated using surface micro-electromechanical systems (MEMS) technology. The electro-optic light modulators are used for testing flat panel displays and the like. Utilizing surface MEMS technology for fabrication allows for significantly thinner electro-optic modulators, enabling the use of pure liquid crystals without the need for thick containment plates.

[0031] U.S. Patent No. 5,432,461, entitled "Method of testing active matrix liquid crystal display substrates," U.S. Patent No. 7,817,333, entitled "Modulator with improved sensitivity and life time," filed February 6, 2007; U.S. Patent No. 8,801,964, entitled "Encapsulated polymer network liquid crystal material, device and applications," filed December 22, 2010; U.S. Patent No. 7,639,319, entitled "Polymer dispersed liquid crystal formulations for modulator fabrication," filed April 7, 2005; and U.S. Patent No. 6,151,153, entitled "Modulator transfer process and assembly," each of which is incorporated herein by reference in its entirety.

[0032] 1A-1B, an electro-optic (EO) modulator 100 according to one or more embodiments of the present disclosure will be described. Electro-optic modulator 100 may also be referred to as an electro-optic light modulator, a liquid crystal-based electro-optic light modulator, etc. Electro-optic modulator 100 is a flat panel display (FPD) spatial light modulator (SLM). Electro-optic modulator 100 is a narrow-gap device having two dielectric layers separated by a polymer stud and an integrated dielectric mirror.

[0033] The electro-optic modulator 100 can include one or more films, layers, or coatings. The one or more film layers selectively allow the transmission of light. For example, the electro-optic modulator 100 can include one or more layers, such as, but not limited to, an anti-reflective coating 102, a glass substrate 104, a transparent electrode 106, an alignment layer 108, a liquid crystal layer 110, alignment studs 112, polymer studs 114, an epoxy seal 115, an alignment layer 116, a polymer layer 118, a dielectric mirror 120, and a hard coat layer 122.

[0034] In some embodiments, the electro-optic modulator 100 includes an anti-reflective coating 102. The anti-reflective coating 102 is sometimes referred to as a dielectric anti-reflective stack.

[0035] In some embodiments, the electro-optic modulator 100 includes a glass substrate 104. The glass substrate 104 may include BK7 glass, etc. The glass substrate 104 is disposed on an anti-reflective coating 102.

[0036] In some embodiments, the electro-optic modulator 100 includes a transparent electrode 106. The transparent electrode 106 may also be referred to as a transparent conductive layer. The transparent electrode 106 is disposed on a glass substrate 104. The transparent electrode 106 may include any conductive coating that is transparent at the wavelength of interest. For example, the transparent electrode 106 may include materials such as, but not limited to, indium tin oxide (ITO), silver nanowires, conductive polythiophenes, and carbon nanotubes. The material may be applied to the glass substrate by techniques such as sputtering and masking. The transparent electrode 106 may have a thickness. For example, the transparent electrode 106 may have a thickness of 1600-1700 Å. In some embodiments, the transparent electrode 106 may have a thickness of 1600-1700 Å with a variation of less than 1.8% across the entire transparent electrode 106. The transparent electrode 106 can capacitively couple to a sample to induce a local voltage and, similarly, an electric field. The local voltage can generate an electric field.

[0037] In some embodiments, the electro-optic modulator 100 includes an alignment layer 108. The alignment layer 108 is disposed on the transparent electrode 106. The alignment layer 108 is a dielectric. The alignment layer 108 is disposed between the liquid crystal layer 110 and the transparent electrode 106. The alignment layer 108 is a dielectric and is disposed between the liquid crystal layer 110 and the transparent electrode 106 to insulate the liquid crystal layer 110 from the transparent electrode 106. The alignment layer 108 has a refractive index (n). For example, the alignment layer 108 may have a refractive index between 1.51 and 1.55. The alignment layer 108 is a dielectric and may include any material having a desired refractive index. In some embodiments, the alignment layer 108 is made of silicon oxynitride (SiO x N y ) In some embodiments, the alignment layer 108 is silicon dioxide (SiO2). The alignment layer 108 has a thickness. For example, the alignment layer 108 may have a thickness of 230 to 270 Å. The alignment layer may generally refer to a layer that assists in aligning the liquid crystal layer 110. Because the alignment layer is formed from a photoresponsive material, the alignment layer may also be referred to as a photoresponsive layer. The photoresponsive material may be photopatterned to form an alignment layer for the liquid crystal material.

[0038] In some embodiments, the alignment layer 108 is etched. One or more grooves are etched into the alignment layer 108 (not shown). The grooves may also be referred to as continuous nanotrenches, lines, etc. The grooves may be created by etching, plasma ashing, and stripping. In some embodiments, the grooves are etched to a depth. For example, the grooves may be etched to a depth of 200 Å. In some embodiments, the grooves define a checkerboard pattern in the alignment layer 108. The alignment layer 108 has a line spacing (LS). The line spacing is the distance between grooves. In some embodiments, the line spacing may be 350 nm or less. In some embodiments, the line spacing may be 120 nm or less. In some embodiments, the line spacing may be 110 nm or less. Although the electro-optic modulator 100 is described as including the alignment layer 108, this is not intended as a limitation of the present disclosure. It is contemplated that the transparent electrode 106 may have one or more grooves etched into it.

[0039] In some embodiments, electro-optic modulator 100 includes a liquid crystal layer 110. Liquid crystal layer 110 is disposed on alignment layer 108. In some embodiments, liquid crystal layer 110 is vacuum-inserted or capillary-filled between alignment layer 108 and alignment layer 116. In some embodiments, liquid crystal layer 110 is discontinuous. Alignment studs 112 and polymer studs 114 extend through liquid crystal layer 110.

[0040] The liquid crystal layer 110 is sensitive to an electric field. The optical properties of the liquid crystal layer 110 change when an electric field is applied across the liquid crystal. The intensity of light transmitted through the liquid crystal layer 110 is modulated by variations in the intensity of the electric field across the liquid crystal layer 110. Depending on the magnitude of the electric field applied to the liquid crystal layer 110, the light transmitted through the liquid crystal layer 110 can change. This electric field causes the liquid crystal layer 110 to align in the direction of the electric field.

[0041] In some embodiments, the liquid crystal layer 110 is a pure liquid crystal. The pure liquid crystal is a nematic liquid crystal. The liquid crystal layer 110 is homogeneously aligned in the absence of an electric field. The liquid crystal layer 110 is homogeneously aligned by the alignment layers 108 and 116 in the absence of an electric field. The liquid crystal layer 110 is not a polymer / liquid crystal blend layer. For example, the liquid crystal layer 110 is not a nematic curvilinearly aligned phase (NCAP) or polymer dispersed liquid crystal (PDLC). In this case, the liquid crystal in the liquid crystal layer 110 is not encapsulated as droplets in a polymer. The liquid crystal layer 110 has a thickness. For example, the liquid crystal layer 110 has a thickness of 2 to 5 micrometers (um). The liquid crystal layer 110 is significantly thinner than a polymer / liquid crystal blend NCAP or PDLC material. By utilizing a pure liquid crystal rather than an NCAP or PDLC, modulator sensitivity and defect detectability should be significantly improved. Thus, electro-optic modulator 100 provides greater sensitivity and throughput in detecting defects during flat panel display manufacturing.

[0042] In some embodiments, the electro-optic modulator 100 includes alignment studs 112. The alignment studs 112 are disposed above or below the alignment layer 108. The alignment studs 112 separate the polymer studs 114 and the liquid crystal layer 110. In some embodiments, the alignment studs 112 are used as a mold to create the polymer studs 114. The alignment studs 112 extend from the alignment layer 108 to the alignment layer 116. The alignment studs 112 may have a thickness. For example, the alignment studs 112 may have a thickness of 0.3 um + / - 0.012 um. The alignment studs 112 define one or more openings between the alignment studs 112. The liquid crystal layer 110 is applied to the electro-optic modulator 100 through the openings. In some embodiments, the openings are sealed with an adhesive. For example, the openings may be sealed with a UV-curable adhesive, an epoxy resin, or the like.

[0043] In some embodiments, the electro-optic modulator 100 includes polymer studs 114. The polymer studs 114 may include a corrosion-resistant material. The polymer studs 114 are made of a cross-linkable photoresponsive polymer. For example, the polymer studs 114 may include, but are not limited to, polyimide (PI).

[0044] The polymer studs 114 provide mechanical support to the polymer layer 118. For example, the polymer studs 114 support the weight of the polymer layer 118 against the alignment layer 108. In some embodiments, the polymer studs 114 support the weight of the polymer layer 118 against the alignment layer 108 via the alignment studs 112. The polymer studs 114 extend through at least a portion of the liquid crystal layer 110. In some embodiments, the polymer studs 114 extend from the polymer layer 118. The polymer studs 114 extend from the polymer layer 118 through at least a portion of the alignment layer 116 and the liquid crystal layer 110. In some embodiments, the polymer studs 114 extend through at least a portion of the liquid crystal layer 110 to the alignment studs 112. In some embodiments, the polymer studs 114 are disposed on the alignment studs 112.

[0045] The polymer studs 114 may have a width. The width of the polymer studs 114 may be based on the width of the support structure 211 minus twice the thickness of the alignment studs 112 (e.g., on both sides of the polymer studs 114). The polymer studs 114 have a width less than 1.4 um. In some embodiments, the polymer studs 114 have a width between 0.776 and 0.824 um. The electro-optic modulator 100 has a pitch between the polymer studs 114. The pitch defines the distance between the center of one stud 114 and the center of an adjacent stud 114. In some embodiments, the electro-optic modulator 100 has a pitch between the polymer studs 114 of 10 to 20 um. In some embodiments, the polymer studs 114 have a thickness. For example, the polymer studs 114 may have a thickness between 2 and 5 um. In some embodiments, the polymer studs 114 have a sidewall angle. The sidewall angle of the polymer studs 114 may be between 83 and 93 degrees. The 90 degree sidewall angle is perpendicular to the alignment layer 108. The polymer studs 114 may be considered to include a concave shape and / or utilize breadloafing.

[0046] In some embodiments, the electro-optic modulator 100 includes an epoxy seal 115. The epoxy seal 115 may also be referred to as an adhesive seal. The epoxy seal 115 seals the liquid crystal layer 110 between the alignment layer 108 and the alignment layer 116. The epoxy seal 115 is disposed around the edges of the liquid crystal layer 110. The epoxy seal 115 seals the liquid crystal layer 110 and prevents the liquid crystal material from leaking out. The epoxy seal 115 is disposed in the openings defined between the polymer studs 114.

[0047] In some embodiments, the electro-optic modulator 100 includes an alignment layer 116. The alignment layer 116 is disposed above or below the liquid crystal layer 110. The alignment layer 116 is a dielectric material. The alignment layer 116 has a refractive index (n). For example, the alignment layer 116 may have a refractive index between 1.51 and 1.55. The alignment layer 116 is a dielectric material and may include any material having a desired refractive index. In some embodiments, the alignment layer 116 is made of silicon oxynitride (SiO x N y ). In some embodiments, the alignment layer 116 is silicon dioxide (SiO2). The alignment layer 116 has a thickness. For example, the alignment layer 116 may have a thickness of 2880 to 3120 Å. As another example, the alignment layer 116 may have a thickness of 285 to 315 Å.

[0048] In some embodiments, the electro-optic modulator 100 includes a polymer layer 118. The polymer layer 118 may also be referred to as a polymer layer, a polymer film, or the like. The polymer layer 118 is disposed on the alignment layer 116. The alignment layer 108 and the alignment layer 116 are located between the polymer layer 118 and the glass substrate 104. The polymer layer 118 may include a corrosion-resistant material. The polymer layer 118 is made of a cross-linkable photoresponsive polymer. For example, but not limited to, the polymer layer 118 may include polyimide (PI). The polyimide is highly cross-linked to withstand corrosive environments. The polymer layer 118 has a thickness. For example, the polymer layer 118 has a thickness of 4 to 6 μm. Thus, the polymer layer 118 and the polymer studs 114 each include a cross-linked polymer such as polyimide.

[0049] In some embodiments, the electro-optic modulator 100 includes a dielectric mirror 120. The dielectric mirror 120 may also be referred to as a pellicle dielectric mirror, a quarter-wave mirror, or the like. The dielectric mirror 120 is disposed or coated on a polymer layer 118. In some embodiments, the dielectric mirror 120 is bonded to the polymer layer 118 by a carbonyl bond. The dielectric mirror 120 has a reflectivity for light of a desired wavelength. For example, the dielectric mirror 120 has a reflectivity of greater than 80% for light with a wavelength of 570 to 670 nm. The dielectric mirror 120 may have a certain thickness. For example, the thickness of the dielectric mirror 120 is approximately 1 μm. For example, the dielectric mirror 120 may have a thickness of 0.9 μm to 1.1 μm.

[0050] The dielectric mirror is a multilayer dielectric mirror. The multilayer dielectric mirror includes a first material and a second material. The dielectric mirror 120 may start with a first material layer and end with a second material layer. In this regard, the dielectric mirror 120 may be coated with a first material layer, a second material layer, ... a first material layer, and so on. The dielectric mirror 120 may include any number of first and second material layers. For example, the dielectric mirror 120 may include six first material layers and five second material layers, for a total of 11 layers. The first and second material layers have respective thicknesses. The thicknesses depend on the refractive index of the dielectric mirror 120. In some embodiments, the first material layer has a thickness of 790 Å + / - 10%. In some embodiments, the second material layer has a thickness of 1070 Å + / - 10%. The first and second materials may include any suitable materials. For example, the dielectric mirror is made of silicon nitride (SiN x) / silicon dioxide (SiO2) multilayer dielectric mirror. Silicon nitride may be the first material and silicon dioxide may be the second material. As another example, dielectric mirror 120 may be a zirconium dioxide (ZrO2) / silicon dioxide (SiO2) multilayer dielectric mirror. Zirconium dioxide may be the first material and silicon dioxide may be the second material. As another example, dielectric mirror 120 may be hafnium oxide (HfO2) and the second material may be silicon oxide. In some embodiments, the first material may be any element from Group 4B of the periodic table.

[0051] In some embodiments, the dielectric mirror 120 includes a pellicle, which may be disposed adjacent to the polymer layer 118.

[0052] In some embodiments, the electro-optic modulator 100 includes a hard coat layer 122. The hard coat layer 122 is disposed on the dielectric mirror 120. The hard coat layer 122 protects the dielectric mirror 120. The hard coat layer 122 is a photosensitive hard coat. In some embodiments, the hard coat layer 122 includes an organic hard coating. The hard coat layer 122 may include hard coat components described in U.S. Pat. No. 7,099,067. The hard coat layer 122 has a thickness. For example, the hard coat layer 122 has a thickness of 2.37 to 5 μm. The hard coat layer 122 has a hardness. In some embodiments, the hard coat layer 122 has a hardness greater than that of a 5H pencil. The hard coat layer 122 may include a primary hard coating and a thinner slip agent layer.

[0053] 2A-2N, a method 200 according to one or more embodiments of the present disclosure will be described. This method may also be referred to as a fabrication method for manufacturing an electro-optic modulator. The embodiments and enabling techniques described herein above in the context of electro-optic modulator 100 should be construed as extending to this method. However, it is further noted that this method is not limited to the configuration of this electro-optic modulator. Method 200 is an integrated fabrication technique that uses silicon (Si) or silicon germanium (SiGe) as a sacrificial layer and release material on a glass substrate.

[0054] In step 202, a glass substrate 104 is provided. The glass substrate 104 is placed on an anti-reflective coating 102.

[0055] In step 204, a transparent electrode 106 is deposited on the glass substrate 104 by sputter deposition.

[0056] In step 206, the alignment layer 108 is deposited on the transparent electrode 106. The alignment layer 108 is deposited by chemical vapor deposition (CVD) on the transparent electrode 106. The alignment layer 108 is deposited on the transparent electrode 106 by, for example, plasma-enhanced chemical vapor deposition (PECVD).

[0057] This step may also include patterning one or more grooves in the alignment layer 108. The one or more grooves are patterned by etching, plasma ashing, and stripping. For example, the one or more grooves may be patterned by a 248 nm phase shift mask (PSM), 193 nm photolithography, etc.

[0058] In step 208, a sacrificial layer 209 is deposited. The sacrificial layer 209 includes a sacrificial layer 209a deposited on the alignment layer 108. The sacrificial layer 209 includes a sacrificial layer 209b deposited under the antireflective coating 102. The sacrificial layer 209 is deposited by CVD. For example, the sacrificial layer 209 is deposited by PECVD, low-pressure chemical vapor deposition (LPCVD), atmospheric pressure chemical vapor deposition (APCVD), etc. The sacrificial layer 209 may include amorphous silicon (a-Si), polycrystalline silicon (poly-Si), polycrystalline silicon germanium (poly-SiGe), etc. In some embodiments, the sacrificial layer 209a on the alignment layer 108 is a-Si deposited by PECVD. In some embodiments, the sacrificial layer 209b under the antireflective coating 102 is poly-Si or poly-SiGe deposited by one of LPCVD, PECVD, or APCVD. It is believed that deposition of poly-Si and / or poly-SiGe by LPCVD may distort the glass substrate 104, so PECVD or APCVD may be preferable.

[0059] This process may include patterning one or more grooves (not shown) in a sacrificial layer 209a disposed on the alignment layer 108. The one or more grooves are patterned by etching, plasma ashing, and stripping. For example, the one or more grooves may be patterned by 193 nm photolithography or the like. The one or more grooves have a line spacing of 120 nm or less. The grooves form nanotrenches in the a-Si.

[0060] In step 210, support structures 211 are patterned in a sacrificial layer 209a disposed on the alignment layer 108. The support structures 211 are patterned by photolithography, plasma etching, and lift-off. Overetching from the sacrificial layer 209a into the alignment layer 108 is permitted. The support structures 211 provide support for forming the alignment studs 112 and polymer studs 114. The support structures 211 have a pitch, width, height, and sidewall angle. For example, the support structures 211 have a pitch between adjacent support structures 211 of 10 to 20 μm. As another example, the support structures 211 have a width of 1.4 μm. As another example, the support structures 211 have a thickness of 2 to 5 μm. As another example, the support structures 211 have a sidewall angle of 83 to 93 degrees.

[0061] In step 212, alignment studs 112 and alignment layer 116 are deposited on sacrificial layer 209a disposed on alignment layer 108. For example, alignment studs 112 are deposited within support structure 211. Alignment studs 112 and alignment layer 116 are deposited by chemical vapor deposition (CVD). For example, alignment studs 112 and alignment layer 116 are deposited by plasma-enhanced chemical vapor deposition (PECVD). Alignment studs 112 and alignment layer 116 may have a certain stress. For example, alignment studs 112 and alignment layer 116 may have a tensile stress of 50 to 150 MPa.

[0062] In step 214, the polymer studs 114 and polymer layer 118 are spun and cured. For example, the polymer studs 114 are spun into the support structure on the alignment studs 112. As another example, the polymer layer 118 is spun onto the alignment layer 116. The polymer studs 114 and polymer layer 118 may be crosslinked by exposure to light. The polymer studs 114 and polymer layer 118 may also be applied by a developer. The developer may remove the uncrosslinked portions of the polymer studs 114 and polymer layer 118. The polymer studs 114 and polymer layer 118 are cured at a temperature. The polymer studs 114 and polymer layer 118 are cured at an elevated temperature to reduce shrinkage of the polymer studs 114. Shrinkage of the polymer studs 114 is undesirable because the shrinkage may cause the polymer studs 114 to separate from the alignment studs 112. In some embodiments, the polymer studs 114 and polymer layer 118 are cured at a temperature between 350 and 400°C. In some embodiments, the polymer studs 114 and polymer layer 118 are spun as a liquid polyimide and then hardened during curing.

[0063] In step 216, a dielectric mirror 120 is deposited on the polymer layer 118. The dielectric mirror 120 is deposited on the polymer layer 118 by PECVD or sputter deposition. In some embodiments, the dielectric mirror 120 is SiN x and SiO2. In some embodiments, a dielectric mirror 120 is deposited on the polymer layer 118 by forming alternating layers of ZrO2 and SiO2. The dielectric mirror 120 may have a certain stress. For example, the dielectric mirror 120 may have a tensile stress of 50-150 MPa. In some embodiments, the polymer layer 118 is pretreated with a CF4 / O2 etch to form carbonyl bonds on the polymer layer 118 to improve adhesion of the dielectric mirror 120 to the polymer layer 118.

[0064] In step 218, the active area 219 is patterned from the electro-optic modulator 100. The active area 219 is patterned using a photoresist (PR) strip. The photoresist (PR) strip conforms to the polymer layer 118. The active area 219 may also be referred to as the modulation definition. In some embodiments, the active area 219 is patterned based on the critical dimension (CD) of the array being tested. The active area 219 is patterned through the dielectric mirror 120, the polymer layer 118, the alignment layer 116, the sacrificial layer, and the alignment layer 108. In some embodiments, the active area 219 is patterned down to the transparent electrode 106. In some embodiments, the active area 219 is patterned into the transparent electrode 106. For example, the active area 219 may be patterned up to 500 Å into the transparent electrode 106.

[0065] In step 220, a hard coat layer 122 is deposited on the dielectric mirror 120. In some embodiments, the hard coat layer 122 is spun onto the dielectric mirror 120 and cured. To prevent cracking of the dielectric mirror 120, the hard coat layer 122 may be cured using a low temperature (LT) cure.

[0066] In step 222, the sacrificial layer is removed. The sacrificial layer can be removed by taping, cutting, tape-off, backside etching, and peeling. In some embodiments, the polymer layer 118 is strongly anchored at the edges to tension the polymer layer 118 against tensile stress. Once the sacrificial layer is removed, the electro-optic modulator 100 defines a cavity between the alignment layer 108 and the alignment layer 116. The electro-optic modulator 100 may also define one or more openings. The cavity can be accessed through the one or more openings. The one or more openings are defined at the edges of the active area.

[0067] In step 224, a liquid crystal layer 110 is applied between alignment layer 108 and alignment layer 116. The liquid crystal layer 110 is applied through one or more openings. In some embodiments, the liquid crystal layer 110 is applied by vacuum insertion or capillary action. For example, the liquid crystal layer 110 may be applied throughout the cavity by capillary action. Adding the liquid crystal layer 110 throughout the cavity by capillary action is different from the lamination method used for fabricating NCAP and PDLC modulators. This step may further include sealing the one or more openings with an epoxy seal 115.

[0068] 3, an electro-optic modulator 300 according to one or more embodiments of the present disclosure will be described. The description of electro-optic modulator 100 with respect to electro-optic modulator 300 is incorporated herein by reference in its entirety.

[0069] The electro-optic modulator 300 can include one or more films, layers, or coatings. The one or more film layers selectively allow light transmission. For example, the electro-optic modulator 300 can include one or more layers, such as, but not limited to, a glass substrate 104, a transparent electrode 106, an alignment layer 108, a liquid crystal layer 110, a polymer stud 114, an epoxy seal 115, an alignment layer 116, a polymer layer 118, a dielectric mirror 120, and a hard coat layer 122. The descriptions of the glass substrate 104, the transparent electrode 106, the alignment layer 108, the liquid crystal layer 110, the polymer stud 114, the epoxy seal 115, the alignment layer 116, the polymer layer 118, the dielectric mirror 120, and the hard coat layer 122 of the electro-optic modulator 100 are incorporated herein by reference in their entirety with respect to the electro-optic modulator 300. Electro-optic modulator 300 differs from electro-optic modulator 100 in that electro-optic modulator 100 includes alignment studs 112, while electro-optic modulator 300 does not include alignment studs 112. Electro-optic modulator 300 also differs from electro-optic modulator 100 in that the polymer studs 114 of electro-optic modulator 100 extend from, and are not separated from, polymer layer 118, while the polymer studs 114 of electro-optic modulator 300 are separated from polymer layer 118 by alignment layer 116.

[0070] In some embodiments, the polymer studs 114 extend from the alignment layer 116. The polymer studs 114 are separated from the polymer layer 118 by the alignment layer 116. As such, the polymer studs 114 may or may not extend from the polymer layer 118. The polymer studs 114 extend from the alignment layer 116 to the alignment layer 108. The polymer studs 114 are disposed on the alignment layer 108. The polymer studs 114 mechanically support the polymer layer 118 by supporting the weight of the polymer layer 118 against the alignment layer 108 via the alignment layer 116 and the polymer studs 114. In this example, the electro-optic modulator 300 does not have alignment studs 112. In some embodiments, the polymer studs 114 extend entirely through the liquid crystal layer 110. For example, the polymer studs 114 extend through the liquid crystal layer 110 to the alignment layer 108.

[0071] 4A-4M, a method 400 according to one or more embodiments of the present disclosure will be described. This method may also be referred to as a fabrication method for manufacturing an electro-optic modulator. The embodiments and enabling techniques described herein above in the context of electro-optic modulator 100, method 200, and electro-optic modulator 300 should be construed as extending to this method. However, it is further noted that this method is not limited to the configurations of electro-optic modulator 100, method 200, and electro-optic modulator 300. Method 400 is a two-part fabrication technique using a delaminated Si substrate and flip-bonding of a polymer to a glass substrate.

[0072] In step 402, silicon nitride (SiN x ) layer is deposited on a Si substrate 403. x The layer is deposited by CVD, e.g., SiN by LPCVD. x 106 layers are deposited. SiN x The layer has a thickness, e.g., SiN x The layer thickness is 1100 Å.

[0073] In step 404, the dielectric mirror 120 is formed of SiNx The dielectric mirror 120 is deposited by PECVD or sputter deposition. x The layer serves as the first layer of the dielectric mirror 120. The dielectric mirror 120 is made of SiN x The dielectric mirror 120 may have a certain stress. For example, the dielectric mirror 120 may have a tensile stress of 50 to 150 MPa.

[0074] In step 406, a polymer layer 118 is spun and cured. The polymer layer 118 is spun and cured onto the dielectric mirror 120. The polymer layer 118 is cured at a temperature. The polymer layer 118 is cured at a high temperature to reduce stress in the dielectric mirror 120 due to shrinkage of the polymer layer 118. In some embodiments, the polymer layer 118 is cured at a temperature between 350 and 400°C. In some embodiments, the polymer layer 118 is spun as a liquid polyimide and then hardened during curing. The polymer layer 118 may be spun to a thickness of 3.8 to 4.2 um.

[0075] In step 408, an alignment layer 116 is deposited on the polymer layer 118. The alignment layer 116 is deposited by CVD. For example, the alignment layer 116 is deposited by PECVD. In some embodiments, the alignment layer 116 is deposited to a thickness. For example, the alignment layer 116 is deposited to a thickness of 285 to 315 Å.

[0076] This process may also include patterning one or more grooves in the alignment layer 116. The one or more grooves are patterned by etching, plasma ashing, and stripping. In some embodiments, the grooves are etched to a depth. For example, the grooves may be etched to a depth of 250 Å. In some embodiments, the grooves define a checkerboard pattern in the alignment layer 116. The alignment layer 116 has a line spacing (LS). The line spacing is the distance between the grooves. In some embodiments, the line spacing may be 300 nm or less. In some embodiments, the line spacing may be 110 nm or less.

[0077] In step 410, polymer studs 114 are deposited on the alignment layer 116. In some embodiments, the polymer studs 114 may be deposited using two masks. In some embodiments, the polymer studs 114 may be deposited using alignment with one mask. In some embodiments, the polymer studs 114 are post-treated with O2 / CF4 to form carbonyl bonds between the polymer studs 114 and the alignment layer 116 to improve adhesion of the polymer studs 114 to the alignment layer 116.

[0078] In step 412, the transparent electrode 106 is deposited by sputter deposition on the glass substrate 104, without the anti-reflective coating 102 in place at this time.

[0079] In step 414, the alignment layer 108 is deposited on the transparent electrode 106. The alignment layer 108 is deposited on the transparent electrode 106 by chemical vapor deposition (CVD). The alignment layer 108 is deposited on the transparent electrode 106 by, for example, plasma-enhanced chemical vapor deposition (PECVD). The alignment layer 108 may require a deep ultraviolet (DUV) polarizer mask to align with the desired periodicity.

[0080] The steps of depositing the transparent electrode 106 on the glass substrate 104 and depositing the alignment layer 108 are carried out by depositing silicon nitride (SiNx ) layer, depositing the dielectric mirror 120, spinning and curing the polymer layer 118, and depositing the alignment layer 116 on the polymer layer 118.

[0081] In step 416, the alignment layer 108 is bonded onto the polymer studs 114. The glass substrate 104, transparent electrode 106, and alignment layer 108 are inverted and positioned on top of the polymer studs 114. The alignment layer 108 is bonded onto the polymer studs 114 by vacuum pressing. The alignment layer 108 is pressed at the glass transition temperature of the polymer studs 114. For example, the polymer studs 114 may have a glass transition temperature of 150-200°C.

[0082] In step 418, the Si substrate is peeled from the dielectric mirror 120. The Si substrate is peeled from the dielectric mirror 120 by etching the Si substrate. For example, the Si substrate may be etched with potassium hydroxide (KOH). The edges of the polymer layer 118 may be clamped together. In some embodiments, the polymer layer 118 requires patterning and a protective layer on the edges, depending on the clamping and etching solution.

[0083] In step 420, a hard coat layer 122 is deposited on the dielectric mirror 120. In some embodiments, the hard coat layer 122 is spun onto the dielectric mirror 120 and cured. To prevent cracking of the dielectric mirror 120, the hard coat layer 122 may be cured using a low temperature (LT) cure.

[0084] In step 422, a liquid crystal layer 110 is applied between the alignment layer 108 and the alignment layer 116. The liquid crystal layer 110 is applied through one or more openings. In some embodiments, the liquid crystal layer 110 is applied by vacuum insertion or capillary insertion. For example, the liquid crystal layer 110 may be applied through the cavity by capillary action. Applying the liquid crystal layer 110 through the cavity by capillary action is different from the lamination method used for fabricating NCAP or PDLC modulators and prevents future damage to the LC sensor when the top Mylar is removed during the assembly process. This step may further include sealing the one or more openings with an epoxy seal 115. In some embodiments, there may be no upstream contour etching and edge cutting / sealing may be required.

[0085] 5, an electro-optic modulator 500 according to one or more embodiments of the present disclosure will be described. The descriptions of electro-optic modulator 100 and electro-optic modulator 300 are incorporated herein by reference in their entirety with respect to electro-optic modulator 500.

[0086] The electro-optic modulator 100 can include one or more films, layers, or coatings. The one or more film layers selectively allow light transmission. For example, the electro-optic modulator 100 can include one or more layers, such as, but not limited to, an anti-reflective coating 102, a glass substrate 104, a transparent electrode 106, an alignment layer 108, a liquid crystal layer 110, alignment studs 112, polymer studs 114, an epoxy seal 115, an alignment layer 116, a polymer layer 118, a dielectric mirror 120, and a hard coat layer 122. The descriptions of the anti-reflective coating 102, the glass substrate 104, the transparent electrode 106, the alignment layer 108, the liquid crystal layer 110, alignment studs 112, polymer studs 114, an epoxy seal 115, an alignment layer 116, a polymer layer 118, a dielectric mirror 120, and a hard coat layer 122 of the electro-optic modulator 100, with respect to the electro-optic modulator 500, are incorporated herein by reference in their entireties. The electro-optic modulator 500 also includes a dielectric stud 502 .

[0087] Electro-optic modulator 500 is similar to electro-optic modulator 100, except that electro-optic modulator 500 has a dielectric mirror 120 between alignment layer 116 and polymer layer 118. Dielectric mirror 120 is disposed on alignment layer 116. Polymer layer 118 is disposed on dielectric mirror 120.

[0088] Alignment studs 112 extend from alignment layer 116 through liquid crystal layer 110 to alignment layer 108. Alignment studs 112 are used as a mold to create dielectric studs 502.

[0089] The electro-optic modulator 500 includes a dielectric stud 502. The dielectric stud 502 extends from the dielectric mirror 120. The dielectric stud 502 extends from the dielectric mirror 120 through a first portion of the liquid crystal layer 110. The dielectric stud 502 extends through a first portion from the dielectric mirror 120 to the alignment stud 112. The dielectric stud 502 is disposed on the alignment stud 112. The alignment stud 112 separates the dielectric stud 502 from the liquid crystal layer 110. The alignment stud 112 also separates the dielectric stud 502 from the alignment layer 108. The dielectric stud 502 is used as a mold to create a polymer stud 114.

[0090] The electro-optic modulator 500 includes a polymer stud 114. The polymer stud 114 extends from a polymer layer 118. The polymer stud 114 extends from the polymer layer 118 through the dielectric mirror 120 and the alignment layer 116. The polymer stud 114 extends from the polymer layer 118 through the dielectric mirror 120 and the alignment layer 116, through a second portion of the liquid crystal layer 110, and to a dielectric stud 502. The second portion of the liquid crystal layer 110 is smaller than the first portion of the liquid crystal layer 110. In this case, the dielectric stud 502 extends further into the liquid crystal layer 110 than the polymer stud 114. The polymer stud 114 is disposed on the dielectric stud 502. The dielectric stud 502 separates the alignment stud 112 and the polymer stud 114.

[0091] The electro-optic modulator 500 can be fabricated by a process similar to method 200. While method 200 has been described as including spinning and curing the polymer studs 114 and polymer layer 118, followed by depositing the dielectric mirror 120, this is not intended as a limitation of the present disclosure. In some embodiments, the dielectric mirror 120 can be deposited before spinning and curing the polymer studs 114 and polymer layer 118. The dielectric mirror 120 can then include the dielectric studs 502 disposed within a support structure above the alignment studs 112. The polymer layer 118 can then be deposited on the dielectric mirror 120, and the polymer studs 114 can then be deposited within a support structure above the dielectric studs 502. This process can be considered a mirror-first process, as opposed to a polymer-layer-first process. In some embodiments, the mirror-first process can use a photosensitive polymer layer 118.

[0092] 6 is a conceptual diagram illustrating an imaging system 600 in accordance with one or more embodiments of the present disclosure. For purposes of this disclosure, the term "imaging system" is interchangeable with the term "imaging tool." The imaging system 600 may also be referred to as an automated optical inspection (AOI) system, a voltage imaging optical system (VIOS), an array checker, etc.

[0093] The imaging system 600 can generally include any type of suitable imaging tool, such as, but not limited to, voltage imaging. Voltage imaging can be used to detect and measure defects in flat panel thin film transistor (TFT) arrays. The performance of the TFT array is simulated as if assembled into TFT cells, and the characteristics of the TFT array are then measured by indirectly measuring the actual voltage distribution on the panel using an electro-optic modulator (100, 300, 500), or so-called voltage imaging. Voltage imaging can be performed by the imaging system 600. The imaging system 600 can include one or more components for inspecting such TFT arrays or other samples.

[0094] The electro-optic modulator (100, 300, 500) can be advantageous for some imaging tasks, such as modulating the light source of an imaging system 600 to aid in the detection of one or more defects in a sample 611, such as, but not limited to, a thin film transistor (TFT) array, a liquid crystal display (LCD) panel, or an OLED panel. The TFT array may be formed on a substrate, such as a thin, transparent plate of glass. The TFT array may include one or more printed layers. The printed layers can be formed on the substrate through several procedures, such as, but not limited to, one or more material deposition steps, one or more lithography steps, and one or more etching steps. Fabrication may be performed in stages, with materials (e.g., indium tin oxide (ITO)) deposited on previous layers or on a glass substrate according to a process pattern. During fabrication, the printed layers are manufactured within selected tolerances to properly construct the final device. The printed layers may exhibit defects outside the selected tolerances. The characteristics of the TFT array can be measured by the imaging system 600 to detect defects.

[0095] In an embodiment, the imaging system 600 includes an illumination source 606 for generating illumination 608. The illumination 608 may include one or more selected wavelengths of light, including, but not limited to, vacuum ultraviolet (VUV), deep ultraviolet (DUV), ultraviolet (UV), visible light, or infrared (IR). The illumination source 606 may further generate illumination 608 including any range of selected wavelengths. In an embodiment, the illumination source 606 may include a spectrally tunable illumination source to generate illumination 608 having a tunable spectrum.

[0096] In an embodiment, illumination source 606 directs illumination 608 toward sample 611 via illumination path 609. Illumination path 609 may include one or more lenses 612 or additional illumination optics 614 suitable for modifying and / or adjusting the illumination 608. For example, the one or more illumination optics 614 may include, but are not limited to, one or more polarizers, one or more filters, one or more beam splitters, one or more diffusers, one or more homogenizers, one or more apodizers, one or more shapers, one or more shutters (e.g., mechanical shutters, electro-optic shutters, acousto-optic shutters, etc.), one or more aperture stops, and / or one or more field stops.

[0097] In an embodiment, the imaging system 600 includes an electro-optic modulator 100. The electro-optic modulator (100, 300, 500) is positioned in the path of illumination 608 from an illumination source 606. The electro-optic modulator (100, 300, 500) can modulate one or more properties of the illumination 608. During operation, light is transmitted through a portion of the electro-optic modulator (100, 300, 500), and defects can be detected by observing changes in the reflected or transmitted light. The electro-optic modulator (100, 300, 500) is separated from the sample 611 by an air gap. The electro-optic modulator (100, 300, 500) can be positioned a selected few microns (e.g., 5-75 microns) above the surface of a sample 611 (e.g., a TFT array), and a voltage bias is applied between transparent electrodes of a layer of indium tin oxide (hereinafter "ITO") on the surface of the electro-optic modulator (100, 300, 500). The electro-optic modulator (100, 300, 500) then capacitively couples to the sample 611, and as a result, the electric field associated with the sample 611 is sensed by one or more layers (e.g., layers containing liquid crystals) of the electro-optic modulator (100, 300, 500). The intensity of incident light transmitted through the liquid crystals of the electro-optic modulator is varied (i.e., modulated) based on the electric field strength sensed by the liquid crystals. For example, in areas where normal pixels are located, a local voltage potential is applied (e.g., capacitive coupling between the sample 611 and the electro-optical modulator (100, 300, 500)), causing one or more membranes of the electro-optical modulator 100 to become locally translucent. In the locally translucent areas, light from the light source 606 can pass through the electro-optical modulator (100, 300, 500), reflect off the sample 611, and pass to the collection path 622 (e.g., for capture by the detector 604). As another example, in areas where no voltage potential is applied (e.g., no capacitive coupling), one or more membranes of the electro-optical modulator (100, 300, 500) remain locally opaque. When the electro-optical modulator (100, 300, 500) is locally opaque, light from the light source 606 is scattered or otherwise prevented from passing to the sample 611. In this manner, a transmission-voltage (TV) curve can be determined by applying a voltage.The characteristic switching voltage of the electro-optic modulator 100 may correspond to the voltage across the electro-optic modulator (100, 300, 500) at which light transmission through the electro-optic modulator (100, 300, 500) has the greatest sensitivity to changes in voltage. For example, the switching voltage may correspond to the electric field strength at which a given percentage of the liquid crystal molecules substantially align with the electric field to allow light transmission.

[0098] In an embodiment, sample 611 includes a thin film transistor (TFT) array. For example, sample 611 may include pixel elements disposed between inactive areas. Sample stage 618 may include any device suitable for positioning sample 611 within imaging system 600.

[0099] In an embodiment, the detector 604 is configured to capture radiation emitted from the sample 611 (e.g., sample light 620) and through a collection path 622. For example, the collection path 622 may, but is not required to, include an electro-optic modulator (100, 300, 500), a collection lens (e.g., an objective lens), or one or more additional collection path lenses 624. The detector 604 can then receive radiation reflected or scattered from the sample 611 (e.g., by specular reflection, diffuse reflection, etc.) or generated by the sample 611 (e.g., luminescence associated with absorption of the illumination 608, etc.).

[0100] System 600 may include, but is not limited to, a controller 603. Controller 603 may include one or more processors and memory, and may include or be coupled to a user interface 610.

[0101] The collection path 622 may further include any number of collection optics 626 for directing and / or modifying the illumination collected by the electro-optic modulator (100, 300, 500), including, but not limited to, one or more collection path lenses 624, one or more filters, one or more polarizers, or one or more blocks. Additionally, the collection path 622 may include a field stop to control the spatial extent of the sample imaged onto the detector 604 or an aperture stop to control the angular extent of illumination from the sample used to generate the image on the detector 604. In another embodiment, the collection path 622 includes an aperture stop positioned in a plane conjugate to the back focal plane of the optics to provide telecentric imaging of the sample. In an embodiment, the imaging system 600 includes a beam splitter 628 oriented such that the electro-optic modulator 100 can simultaneously direct illumination 608 to the sample 611 and collect radiation emitted from the sample 611.

[0102] Detector 604 may include any type of optical detector suitable for measuring illumination received from sample 611. For example, detector 604 may include, but is not limited to, a CCD detector, a TDI detector, a photomultiplier tube (PMT), an avalanche photodiode (APD), a complementary metal-oxide semiconductor (CMOS) sensor, etc. In another embodiment, detector 604 may include a spectroscopic detector suitable for identifying wavelengths of light emitted from sample 611.

[0103] In an embodiment, controller 603 is communicatively coupled to detector 604. Controller 603 may include one or more processors configured to perform any of a variety of processing steps. In an embodiment, controller 603 is configured to generate and provide one or more control signals configured to perform one or more adjustments to one or more processing tools based on image signals 613 from detector 604.

[0104] The one or more processors of controller 603 may include any processor or processing element known in the art. For purposes of this disclosure, the term “processor” or “processing element” may be broadly defined to encompass any device having one or more processing elements or logic elements (e.g., one or more microprocessor devices, one or more application-specific integrated circuit (ASIC) devices, one or more field-programmable gate arrays (FPGAs), or one or more digital signal processors (DSPs)). In this sense, one or more processors may include any device configured to execute algorithms and / or instructions (e.g., program instructions stored in memory). In one embodiment, the one or more processors may be embodied as a desktop computer, a mainframe computer system, a workstation, an image computer, a parallel processor, a network computer, or any other computer system configured to execute programs configured to operate as described throughout this disclosure or in conjunction with imaging system 600. Additionally, various subsystems of system 600 may include processors or logic elements suitable for performing at least some of the processes described in this disclosure. Therefore, the above description should not be construed as a limitation on embodiments of the present disclosure, but merely as an example. Furthermore, the processes described throughout this disclosure may be performed by a single controller, or alternatively, by multiple controllers. Furthermore, controller 603 may include one or more controllers housed within a common housing or multiple housings. In this manner, any controller or combination of controllers may be packaged separately as a module suitable for integration into imaging system 600. Furthermore, controller 603 may analyze data received from detector 604 and provide the data to additional components within or external to imaging system 600.

[0105] The memory medium may include any storage medium known in the art suitable for storing program instructions executable by the associated processor(s). For example, the memory medium may include a non-transitory memory medium. As another example, the memory medium may include, but is not limited to, read-only memory (ROM), random access memory (RAM), magnetic or optical memory devices (e.g., disks), magnetic tape, solid-state drives, etc. It is further noted that the memory medium may be housed in a common controller housing with the processor(s). In one embodiment, the memory medium may be located remotely relative to the physical location of the processor(s) and controller(s). For example, the processor(s) of the controller 603 may access a remote memory (e.g., a server) accessible via a network (e.g., the Internet, an intranet, etc.).

[0106] In an embodiment, user interface 610 is communicatively coupled to controller 603. In an embodiment, user interface 610 may include, but is not limited to, one or more desktops, laptops, tablets, etc. In an embodiment, user interface 610 includes a display used to display system 600 data to a user. The display of user interface 610 may include any display known in the art. For example, the display may include, but is not limited to, a liquid crystal display (LCD), an organic light emitting diode (OLED)-based display, or a CRT display. Those skilled in the art will recognize that any display device that can be integrated with user interface 610 is suitable for practice in the present disclosure. In an embodiment, a user can input selections and / or commands in response to data displayed to the user via a user input device of user interface 610.

[0107] Referring again to Figures 1A-6 generally, the electro-optic modulators (100, 300, 500) are believed to offer several advantages over NCAP-based EO modulators. The electro-optic modulators (100, 300, 500) improve the noise, dynamic range, and defect sensitivity of the modulator product, as well as lower the threshold electric field for defect detection during flat panel manufacturing. The electro-optic modulators (100, 300, 500) achieve a desired level of flatness. The electro-optic modulators (100, 300, 500) reduce part-to-part variations due to mechanical manufacturing procedures. The electro-optic modulators (100, 300, 500) have improved defect detection sensitivity and a reduced threshold electric field, which are necessary for defect metrology during the manufacturing of flat panel displays.

[0108] In some embodiments, the electro-optic modulator (100, 300, 500) can have an area. For example, the electro-optic modulator (100, 300, 500) can have an area of ​​130 mm x 130 mm to an area of ​​1 cm x 1 cm.

[0109] As used throughout this disclosure, the term "sample" generally refers to a substrate formed of a semiconductor or non-semiconductor material (e.g., thin film glass, etc.). For example, the semiconductor or non-semiconductor material may include, but is not limited to, single-crystal silicon, gallium arsenide, indium phosphide, or a glass material. A sample may include one or more layers. For example, such layers may include, but are not limited to, resist (including photoresist), dielectric materials, conductive materials, and semiconductor materials. Many different types of such layers are known in the art, and the term sample, as used herein, is intended to encompass samples on which all types of such layers may be formed. The one or more layers formed on a sample may be patterned or unpatterned. For example, a sample may include multiple dies, each having repeatable patterned features. The formation and processing of such layers of material can ultimately result in a completed device. Many different types of devices may be formed on a sample, and the term sample, as used herein, is intended to encompass samples on which any type of device known in the art is fabricated. Furthermore, for the purposes of this disclosure, the terms sample and wafer should be considered interchangeable. Further, for the purposes of this disclosure, the terms patterning device, mask, and reticle should be considered interchangeable.

[0110] It is further contemplated that each of the above method embodiments may include any other step(s) of any other method described herein. Additionally, each of the above method embodiments may be performed by any of the systems described herein. In some embodiments, the method utilizes surface microelectromechanical systems ("surface MEMS") fabrication techniques available at silicon foundries to fabricate electro-optic modulator 100.

[0111] Those skilled in the art will recognize that the operations of components, devices, purposes, and the accompanying explanations described herein are used as examples to clarify the concepts, and that various configurational variations are contemplated. Thus, as used herein, the specific examples described and the accompanying explanations are intended to be representative of their more general types. In general, the use of any specific example is intended to be representative of that type, and the absence of specific components, operations, devices, and purposes should not be considered limiting.

[0112] As used herein, directional terms such as "top," "bottom," "over," "under," "upper," "upward," "lower," "down," and "downward" are intended to define relative positions for purposes of illustration and are not intended to specify an absolute frame of reference. Various modifications to the described embodiments will be apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments.

[0113] With respect to the use of any substantially plural and / or singular terms herein, those skilled in the art will be able to convert from the plural to the singular and / or from the singular to the plural as appropriate to the context and / or application. The various singular / plural permutations are not expressly set forth herein for the sake of clarity.

[0114] The subject matter described herein may illustrate various components contained within or related to other components. It should be understood that such depicted configurations are merely exemplary, and that in fact, many other configurations that achieve the same functionality may be implemented. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively “associated” such that the desired functionality is achieved. Thus, any two components herein that are combined to achieve a particular function can be considered “associated” with each other such that the desired functionality is achieved, regardless of configuration or intermediate components. Similarly, any two components so associated can also be considered “connected” or “coupled” to each other to achieve the desired functionality, and any two components that can be so associated can also be considered “combinable” with each other to achieve the desired functionality. Specific examples of combinable components include, but are not limited to, physically intermixable and / or physically interacting components and / or wirelessly interactable and / or wirelessly interacting components and / or logically interacting and / or logically interacting components.

[0115] It should further be understood that the present invention is defined by the appended claims. In general, it will be understood by those skilled in the art that the words used herein, and particularly in the appended claims (e.g., the body of the appended claims), are generally intended as "open" words (e.g., the word "including" should be interpreted as "including but not limited to," the word "having" should be interpreted as "having at least," the word "including" should be interpreted as "including but not limited to," etc.). Where a claim set forth with a specific number of preambles is intended, such intention will be explicitly set forth in the claim; in the absence of such a preamble, it will be further understood by those skilled in the art that no such intention exists. For example, to aid in understanding, the following appended claims may include the use of the preamble phrases "at least one" and "one or more" to preamble the claim set forth. However, the use of such phrases should not be construed as meaning that the preface of a claim recitation with the indefinite article "a" or "an" limits any particular claim that includes such a prefaced claim recitation to an invention that includes only one of such recitations, even if the same claim includes the prefaced phrase "one or more" or "at least one" and an indefinite article such as "a" or "an" (e.g., "a" and / or "an" should typically be interpreted to mean "at least one" or "one or more"). The same applies to the use of definite articles used to preface claim recitations. Moreover, even if a particular number of prefaced claim recitations is explicitly recited, those skilled in the art will recognize that such recitations typically mean at least the recited number (e.g., the recitation "two recitations" by itself, without any other modifiers, typically means at least two recitations, or more than two recitations).Furthermore, when formulas similar to "at least one of A, B, and C, etc." are used, generally such configurations are intended in the sense that one of ordinary skill in the art would understand the formula (e.g., "a system having at least one of A, B, and C" includes, but is not limited to, systems having A only, B only, C only, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). When formulas similar to "at least one of A, B, or C, etc." are used, generally such configurations are intended in the sense that one of ordinary skill in the art would understand the formula (e.g., "a system having at least one of A, B, or C" includes, but is not limited to, systems having A only, B only, C only, A and B together, A and C together, B and C together, and / or A, B, and C together, etc.). It will be further understood by those skilled in the art that any substantially disjunctive words and / or phrases presenting two or more alternative terms, whether in the specification, claims, or drawings, should be understood to contemplate the possibility of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" would be understood to include the possibilities of "A" or "B" or "A and B."

[0116] It is believed that the present disclosure and many of its attendant advantages will be understood from the foregoing description, and it will be apparent that various changes in form, construction and arrangement of elements can be made without departing from the disclosed subject matter and without sacrificing all of the advantages of that subject matter. The described embodiments are merely illustrative, and it is intended that the following claims encompass all such modifications. It is further understood that the invention is defined by the appended claims.

Claims

1. 1. An electro-optic modulator comprising: Glass substrate, a transparent electrode disposed on the glass substrate; a first alignment layer disposed on the transparent electrode; a liquid crystal layer disposed on the first alignment layer; a second alignment layer disposed on the liquid crystal layer; a polymer layer disposed on the second alignment layer; a plurality of polymer studs, the plurality of polymer studs extending through at least a portion of the liquid crystal layer, the plurality of polymer studs providing mechanical support to the polymer layer; a dielectric mirror disposed on the polymer layer; and a hard coat layer disposed on the dielectric mirror; 1. An electro-optic modulator comprising:

2. 10. The electro-optic modulator of claim 1, wherein the liquid crystal layer has a thickness of 2 to 5 micrometers.

3. 10. The electro-optic modulator of claim 1, wherein the liquid crystal layer is neither a nematic curvilinearly aligned liquid crystal nor a polymer dispersed liquid crystal.

4. The electro-optic modulator of claim 1 , wherein the plurality of polymer studs extend from the polymer layer through the second alignment layer and at least the portion of the liquid crystal layer.

5. 5. The electro-optic modulator of claim 4, comprising a plurality of alignment studs, the plurality of alignment studs extending from the second alignment layer to the first alignment layer, the plurality of polymer studs extending through at least the portion of the liquid crystal layer to the alignment studs, and the plurality of polymer studs disposed on the plurality of alignment studs.

6. The electro-optic modulator of claim 5 including an anti-reflective coating, the glass substrate being disposed on the anti-reflective coating.

7. 2. The electro-optic modulator of claim 1, wherein the plurality of polymer studs extend from the second alignment layer through the liquid crystal layer to the first alignment layer, the plurality of polymer studs being separated from the polymer layer by the second alignment layer.

8. 10. The electro-optic modulator of claim 1, wherein each of the plurality of polymer studs has a width of less than 1.4 micrometers and a thickness of 2 to 5 micrometers.

9. 9. The electro-optic modulator of claim 8, wherein each of the plurality of polymer studs has a sidewall angle of between 83 and 93 degrees.

10. The electro-optic modulator of claim 1 , wherein the transparent electrode comprises at least one of indium tin oxide (ITO) or silver nanowires.

11. 10. The electro-optic modulator of claim 1, wherein the first alignment layer and the second alignment layer each comprise at least one of silicon oxynitride or silicon dioxide.

12. 2. The electro-optic modulator of claim 1, wherein the first alignment layer and the second alignment layer each have a refractive index between 1.51 and 1.

55.

13. The electro-optic modulator of claim 1 , wherein the polymer layer and the plurality of polymer studs each comprise a cross-linked polymer.

14. 2. The electro-optic modulator of claim 1, wherein the dielectric mirror has a reflectivity of more than 80% for light with a wavelength of 570 to 670 nm.

15. 10. The electro-optic modulator of claim 1, wherein the dielectric mirror is a stack of alternating layers of silicon nitride and silicon dioxide.

16. 10. The electro-optic modulator of claim 1, wherein the dielectric mirror is a stack of alternating layers of zirconium oxide and silicon dioxide.

17. 10. The electro-optic modulator of claim 1, including an epoxy seal, said epoxy seal sealing said liquid crystal layer between said first alignment layer and said second alignment layer.

18. 1. An imaging system, comprising: an illumination source configured to generate illumination; Sample stage, a detector for generating an image of at least a portion of the sample; and an electro-optic modulator disposed in a path of the illumination from the illumination source and separated from the sample by an air gap, the electro-optic modulator comprising: Glass substrate, a transparent electrode disposed on the glass substrate; a first alignment layer disposed on the transparent electrode; a liquid crystal layer disposed on the first alignment layer; a second alignment layer disposed on the liquid crystal layer; a polymer layer disposed on the second alignment layer; a plurality of polymer studs, the plurality of polymer studs extending through at least a portion of the liquid crystal layer, the plurality of polymer studs providing mechanical support to the polymer layer; a dielectric mirror disposed on the polymer layer; and a hard coat layer disposed on the dielectric mirror; Imaging system.

19. 1. An electro-optic modulator comprising: Glass substrate, a transparent electrode disposed on the glass substrate; a first alignment layer disposed on the transparent electrode; a liquid crystal layer disposed on the first alignment layer; a second alignment layer disposed on the liquid crystal layer; a plurality of alignment studs, the plurality of alignment studs extending from the second alignment layer through the liquid crystal layer to the first alignment layer; a dielectric mirror disposed on the second alignment layer; a plurality of dielectric studs, the plurality of dielectric studs extending from the dielectric mirror through a first portion of the liquid crystal layer to the plurality of alignment studs, the plurality of dielectric studs being disposed on the plurality of alignment studs; a polymer layer disposed on the dielectric mirror; and a plurality of polymer studs, the plurality of polymer studs extending from the polymer layer through the dielectric mirror, the second alignment layer and a second portion of the liquid crystal layer to the plurality of dielectric studs, the plurality of polymer studs being disposed on the plurality of dielectric studs; 1. An electro-optic modulator comprising:

20. 20. The electro-optic modulator of claim 19, wherein the liquid crystal layer has a thickness of 2 to 5 micrometers.

21. 20. The electro-optic modulator of claim 19, wherein the liquid crystal layer is neither a nematic curvilinearly aligned liquid crystal nor a polymer dispersed liquid crystal.

Images