Planarizing method, planarizing system, and method of manufacturing article

Abstract

To solve a problem that planarization performance may be affected as a baked layer shrinks relative to a cured planarization layer.SOLUTION: A planarizing method comprises the steps of: heating and bowing a superstrate held by a superstrate chuck by introducing a gas having a predetermined temperature into a chamber defined by the superstrate chuck and the superstrate; and heating and planarizing a formable material by contacting the heated bowed superstrate with the formable material, where the predetermined temperature of the gas is higher than a temperature of the formable material prior to contacting the heated bowed superstrate with the formable material.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to substrate processing, and more particularly to a superstrate chuck assembly used for planarizing surfaces in semiconductor manufacturing, and a method of manufacturing an article using the superstrate chuck assembly. [Background technology]

[0002] Planarization and imprinting techniques are useful in manufacturing semiconductor devices. For example, the process for fabricating semiconductor devices involves repeatedly adding and removing material from a substrate. This process can produce multilayer substrates with irregular height variations (i.e., topography), and as more layers are added, the height variations in the substrate can increase. The height variations adversely affect the ability to add additional layers to the multilayer substrate. Apart from that, semiconductor substrates (e.g., silicon wafers) themselves are not always perfectly flat and can contain initial surface height variations (i.e., topography). One way to address this issue is to planarize the substrate between and / or before deposition steps. Various lithographic patterning methods benefit from patterning on a flat surface. In ArFi laser-based lithography, planarization reduces the effects of depth-of-focus (DOF) limitations and improves critical dimension (CD) and critical dimension uniformity. In extreme ultraviolet lithography (EUV), planarization improves feature placement and reduces the effects of DOF limitations. In nanoimprint lithography (NIL), planarization improves feature filling and CD control after pattern transfer.

[0003] This planarization technique, sometimes called inkjet-based adaptive planarization (IAP), involves dispensing a variable droplet pattern of a polymerizable material between the substrate and the superstrate, where the droplet pattern varies depending on the substrate topography. The superstrate is then contacted with the polymerizable material, after which the material is cured (polymerized) on the substrate and the superstrate is removed.

[0004] Curing is typically performed at room temperature, e.g., 20°C. The cured layer is then baked to form a baked layer. The thickness of the baked layer is thinner than the thickness of the photocurable composition. Thickness variations reduce the planarization performance of the baked layer. The resulting surface of the baked layer may have a non-uniform topography, with some areas having locally lower heights and other areas having locally higher heights. A planarization layer with no or at least small height differences across such a surface is desired. Summary of the Invention

[0005] The planarization method includes the steps of heating and bending a superstrate held by the superstrate chuck by introducing a gas having a predetermined temperature into a space defined by the superstrate chuck and the superstrate, and heating and flattening the moldable material by contacting the heated and curved superstrate with a moldable material, wherein the predetermined temperature of the gas is higher than the temperature of the moldable material before contacting the heated and curved superstrate with the moldable material.

[0006] The planarization system includes a superstrate chuck for holding a superstrate, a space at least partially defined by the superstrate chuck, and a gas source in communication with the space for introducing a gas having a predetermined temperature into the space, the predetermined temperature of the gas being between 70°C and 120°C.

[0007] A method for manufacturing an article includes the steps of dispensing a formable material onto a substrate, heating and bending a superstrate held by a superstrate chuck by introducing a gas having a predetermined temperature into a space defined by the superstrate and the superstrate, heating and flattening the formable material by contacting the heated and curved superstrate with the formable material, thereby forming a film of the formable material between the superstrate and the substrate, hardening the film of the formable material to form a hardened layer between the plate (superstrate) and the substrate, and processing the hardened formable material to make an article, wherein the predetermined temperature of the gas is higher than the temperature of the formable material before contacting the heated and curved superstrate with the formable material.

[0008] These and other objects, features, and advantages of the present disclosure will become apparent from a reading of the following detailed description of exemplary embodiments of the present disclosure in conjunction with the accompanying drawings and the appended claims. [Brief explanation of the drawings]

[0009] In order that the features and advantages of the present disclosure may be understood in detail, a more particular description of the embodiments of the present disclosure will be made by reference to the embodiments illustrated in the accompanying drawings. It should be noted, however, that the accompanying drawings illustrate only typical embodiments of the present disclosure and therefore should not be considered as limiting the scope of the present disclosure, which may admit of other equally effective embodiments.

[0010] [Figure 1] 1 is a schematic diagram illustrating an exemplary planarization system according to one aspect of the present disclosure.

[0011] [Figure 2A] 1A-1C are schematic cross-sectional views of an exemplary planarization process according to one aspect of the present disclosure. [Figure 2B]1A-1C are schematic cross-sectional views of an exemplary planarization process according to one aspect of the present disclosure. [Figure 2C] 1A-1C are schematic cross-sectional views of an exemplary planarization process according to one aspect of the present disclosure.

[0012] [Figure 3A] FIG. 2 is a bottom view of an exemplary superstrate chuck assembly according to a first embodiment of the present disclosure.

[0013] [Figure 3B] FIG. 3B is a top view of the superstraight chuck assembly of FIG. 3A.

[0014] [Figure 3C] FIG. 3C is a cross-sectional view taken along line 3C-3C in FIG. 3B.

[0015] [Figure 3D] FIG. 3D shows an enlarged portion of FIG. 3C.

[0016] [Figure 3E] 3D is a perspective view of an enlarged portion of FIG. 3C.

[0017] [Figure 4] FIG. 3B is an exploded view of the SuperStraight chuck assembly of FIGS. 3A-3E.

[0018] [Figure 5] 1 is a flowchart of an exemplary planarization method according to one aspect of the present disclosure.

[0019] [Figure 6A] 6A-6C are a series of schematic cross-sectional views of the planarization method of FIG. 5, in accordance with an exemplary embodiment. [Figure 6B] 6A-6C are a series of schematic cross-sectional views of the planarization method of FIG. 5, in accordance with an exemplary embodiment. [Figure 6C] 6A-6C are a series of schematic cross-sectional views of the planarization method of FIG. 5, in accordance with an exemplary embodiment. [Figure 6D] 6A-6C are a series of schematic cross-sectional views of the planarization method of FIG. 5, in accordance with an exemplary embodiment. [Figure 6E] 6A-6C are a series of schematic cross-sectional views of the planarization method of FIG. 5, in accordance with an exemplary embodiment. [Figure 6F] 6A-6C are a series of schematic cross-sectional views of the planarization method of FIG. 5, in accordance with an exemplary embodiment. [Figure 6G] 6A-6C are a series of schematic cross-sectional views of the planarization method of FIG. 5, in accordance with an exemplary embodiment. [Figure 6H] 6A-6C are a series of schematic cross-sectional views of the planarization method of FIG. 5, in accordance with an exemplary embodiment. [Figure 6I] 6A-6C are a series of schematic cross-sectional views of the planarization method of FIG. 5, in accordance with an exemplary embodiment. [Figure 6J] 6A-6C are a series of schematic cross-sectional views of the planarization method of FIG. 5, in accordance with an exemplary embodiment. [Figure 6K] 6A-6C are a series of schematic cross-sectional views of the planarization method of FIG. 5, in accordance with an exemplary embodiment. [Figure 6L] 6A-6C are a series of schematic cross-sectional views of the planarization method of FIG. 5, in accordance with an exemplary embodiment.

[0020] [Figure 7] 10 is a valve and temperature timing diagram showing the temperature of various components at different moments in the planarization method relative to the initial temperature at the start of the planarization method.

[0021] While the present disclosure will now be described in detail with reference to the figures, it is done so in connection with the exemplary embodiments. It is intended that changes and modifications can be made to the described exemplary embodiments without departing from the true scope and spirit of the subject disclosure as defined by the appended claims. DETAILED DESCRIPTION OF THE INVENTION

[0022] Flattening System 1 illustrates an exemplary system for shaping a surface according to one aspect of the present disclosure. The system for shaping a surface can be, for example, a planarization system or an imprint system. The exemplary embodiment described herein is a planarization system 100. However, these concepts are also applicable to imprint systems. Thus, while terminology throughout this disclosure focuses primarily on planarization, it should be understood that the present disclosure is also applicable to corresponding terminology in the imprint context.

[0023] The planarization system 100 is used to planarize a film on a substrate 102. In the case of an imprint system, the imprint system is used to form a pattern on a film on the substrate. The substrate 102 may be coupled to a substrate chuck 104. The substrate chuck 104 may be, but is not limited to, a vacuum chuck, a pin-type chuck, a groove-type chuck, an electrostatic chuck, an electromagnetic chuck, or the like.

[0024] The substrate 102 and the substrate chuck 104 may be further supported by a substrate positioning stage 106. The substrate positioning stage 106 may provide translational and / or rotational motion along one or more of the x-axis, y-axis, z-axis, θ-axis, ψ-axis, and φ-axis. The substrate positioning stage 106, the substrate 102, and the substrate chuck 104 may also be positioned on a surface plate (not shown). The substrate positioning stage may be part of a positioning system. The substrate positioning stage 106 may include a passive cooling system and / or an active cooling system.

[0025] Disposed away from the substrate 102 is a superstrate 108 (also referred to herein as a plate) having a working surface 112 facing the substrate 102. The superstrate 108 can be formed from materials including, but not limited to, fused silica, quartz, silicon, organic polymers, siloxane polymers, borosilicate glass, fluorocarbon polymers, metals, hardened sapphire, and the like. In one embodiment, the superstrate readily transmits UV light. The working surface 112 is generally the same area size as or slightly smaller than the surface of the superstrate 108. The working surface 112 can include one or more layers of material that differ from the bulk material of the superstrate 108. The one or more layers can have gas transport, surface release, and surface topography properties that enable the planarization system 100 to form a planarized layer with nanometer-scale surface variations. Examples of such superstrates are described in U.S. Patent Application Publication Nos. 2019-0227437, 2020-0286740, and 2023-0167017, each of which is incorporated herein by reference in its entirety.

[0026] The superstrate 108 may be coupled to or held by a superstrate chuck assembly 118 (also referred to herein as a superstrate chuck assembly), which will be described in more detail below. The superstrate chuck assembly 118 may be coupled to a planarization head 120, which is part of a positioning system. In the context of an imprint system, the planarization head may be referred to as an imprint head. The planarization head 120 may be movably coupled to the bridge. The planarization head 120 may include one or more actuators, such as a voice coil motor, a piezoelectric motor, a linear motor, or a nut and screw motor, configured to move the superstrate chuck assembly 118 relative to the substrate 102 in at least the z-axis direction, and potentially in other directions (e.g., the x-axis, y-axis, θ-axis, ψ-axis, and φ-axis).

[0027] The planarization system 100 may further include a fluid dispenser 122. The fluid dispenser 122 may also be movably coupled to the bridge. In one embodiment, the fluid dispenser 122 and the planarization head 120 share one or more of the positioning components. In an alternative embodiment, the fluid dispenser 122 and the planarization head move independently of one another. The fluid dispenser 122 is used to deposit droplets of a liquid formable material 124 (e.g., a photocurable polymerizable material) onto the substrate 102, with the volume of the deposited material varying across an area of ​​the substrate 102 based at least in part on its topographical profile. Different fluid dispensers 122 may use different techniques to dispense the formable material 124. If the formable material 124 is jettable, an inkjet-type dispenser may be used to dispense the formable material. For example, thermal inkjet, microelectromechanical system (MEMS)-based inkjet, valve jet, and piezoelectric inkjet are common techniques for dispensing jettable liquids.

[0028] The planarization system 100 may further include a curing system including a radiation source 126 that directs chemical energy, such as UV radiation, along an exposure path 128. The planarization head 120 and substrate positioning stage 106 may be configured to position the superstrate 108 and substrate 102 in alignment with the exposure path 128. The radiation source 126 directs chemical energy along the exposure path 128 after the superstrate 108 contacts the moldable material 124. FIG. 1 illustrates the exposure path 128 when the superstrate 108 is not in contact with the moldable material 124. This is done for illustrative purposes so that the relative positions of the individual components can be easily identified. Those skilled in the art will understand that the exposure path 128 does not substantially change once the superstrate 108 contacts the moldable material 124.

[0029] Planarization system 100 may further include a camera 136 positioned to view the expansion of moldable material 124 as superstrate 108 contacts it during the planarization process. FIG. 1 illustrates the optical axis 138 of the image field of the field camera. As shown in FIG. 1, planarization system 100 may include one or more optical components (e.g., a dichroic mirror, a beam combiner, a prism, a lens, a mirror, etc.) that combine actinic radiation with light detected by camera 136. Camera 136 may include one or more of a CCD, a sensor array, a line camera, and a photodetector configured to collect light of wavelengths that exhibit contrast between the area under superstrate 108 and the moldable material 124 and the area under superstrate 108 but that are not in contact with moldable material 124. Camera 136 may be configured to provide an image of the expansion of moldable material 124 under superstrate 108 and / or the separation of superstrate 108 from planarization layer 146. The camera 136 may also be configured to measure the interference fringes that change as the moldable material 124 spreads across the gap between the working surface 112 and the substrate surface. The camera 136 may also be configured to measure the interference fringes due to reflections from the working surface 112 and the substrate surface.

[0030] The planarization system 100 may be coordinated, controlled, and / or directed by one or more processors 140 (controllers) that communicate with one or more components and / or subsystems, such as the substrate chuck 104, the substrate positioning stage 106, the superstrate chuck assembly 118, the planarization head 120, the fluid dispenser 122, the radiation source 126, and / or the camera 136. The processor 140 may operate based on instructions in a computer-readable program stored in a non-transitory computer memory 142. The processor 140 may be or include one or more of a CPU, an MPU, a GPU, an ASIC, an FPGA, a DSP, and a general-purpose computer. The processor 140 may be a dedicated controller or a general-purpose computing device adapted to be a controller. Examples of non-transitory computer-readable memory include, but are not limited to, RAM, ROM, CD, DVD, Blu-Ray, hard drives, network attached storage (NAS), intranet-connected non-transitory computer-readable storage devices, and internet-connected non-transitory computer-readable storage devices, etc. All of the method steps described herein may be performed by processor 140.

[0031] During operation, either the planarizing head 120, the substrate positioning stage 106, or both vary the distance between the superstrate 108 and the substrate 102 to define a desired volume (a bounded physical area in three dimensions) to be filled with the moldable material 124. For example, the planarizing head 120 can be moved toward the substrate and apply a force to the superstrate 108 to cause the superstrate to contact and spread the droplet of moldable material 124, as described in further detail herein.

[0032] Planarization Process The planarization process includes the steps shown generally in Figures 2A-2C. As shown in Figure 2A, formable material 124 is dispensed onto substrate 102 in the form of droplets. As previously mentioned, the substrate surface has some topography, which is known based on previous process operations or can be measured using a surface profilometer, AFM, SEM, or an optical surface profiler based on optical interference effects, such as the Zygo NewView 8200. The local volume density of the deposited formable material 124 varies depending on the substrate topography. Superstrate 108 is then placed in contact with formable material 124.

[0033] FIG. 2B illustrates a post-contact step after the superstrate 108 has fully contacted the moldable material 124 but before the polymerization process begins. As the superstrate 108 contacts the moldable material 124, the droplets coalesce to form a moldable material film 144 that fills the space between the superstrate 108 and the substrate 102. Preferably, the filling process is uniform and avoids trapping air bubbles between the superstrate 108 and the substrate 102 to minimize unfilled defects. The polymerization process, or hardening, of the moldable material 124 can be initiated by actinic radiation (e.g., UV radiation). For example, the radiation source 126 in FIG. 1 can provide actinic radiation that hardens, solidifies, and / or crosslinks the moldable material film 144, defining a hardened planarization layer 146 on the substrate 102. Alternatively, hardening of the moldable material film 144 can be initiated using heat, pressure, a chemical reaction, other types of radiation, or any combination thereof. After curing, a planarization layer 146 is formed, and the superstrate 108 can be separated therefrom. Figure 2C shows the cured planarization layer 146 on the substrate 102 after separation of the superstrate 108. The substrate 102 and planarization layer 146 can then be subjected to additional known steps and processes for device (article) fabrication, including, for example, baking, patterning, curing, oxidation, layer formation, deposition, doping, planarization, etching, formable material removal, dicing, bonding, and packaging. The substrate can be processed to fabricate multiple articles (devices).

[0034] An exemplary superstraight chuck assembly 118 according to a first embodiment is shown in Figures 3A-4. Figure 3A shows a bottom view of the superstraight chuck assembly 118. Figure 3B shows a top view of the superstraight chuck assembly 118. Figure 3C shows a cross section taken along line 3C-3C in Figure 3B. Figure 3D shows an enlarged portion 3D of Figure 3C. Figure 3E shows a perspective view of the enlarged portion 3D of Figure 3C.

[0035] 3A-3E, the superstrate chuck assembly 118 can include a superstrate holding member 130, preferably having a ring shape. The superstrate holding member 130 can include a flexible portion 134. As described in U.S. Patent No. 11,728,203, issued August 15, 2023, which is incorporated herein by reference in its entirety, the size of the flexible portion 134 of the superstrate holding member 130 can be varied during the planarization process.

[0036] The superstrate retaining member 130 may further include a cavity 148 (FIGS. 3D and 3E) configured to retain a portion of the superstrate 108 in the flexible portion 134 of the superstrate retaining member 130. The cavity 148 may be an annular cavity concentrically surrounding the central opening 132. The cavity 148 may be disposed adjacent to the inner edge 133 of the superstrate retaining member 130. The cavity 148 may be formed as a recess in the flexible portion 134.

[0037] The superstrate chuck assembly 118 may further include an optically transparent member 150 covering the central opening 132 of the superstrate holding member 130. In an exemplary embodiment, the optically transparent member 150 is preferably transparent to UV light and has high UV light transmittance. That is, the material composition of the optically transparent member 150 may be selected so that the UV light used to cure the moldable material passes through the optically transparent member 150. In an embodiment, if the optically transparent member 150 transmits UV light, the optically transparent member may be made of a material that transmits more than 80% of light having a wavelength between 310 and 700 nm (i.e., UV light and visible light), such as sapphire or fused silica. In another exemplary embodiment, the optically transparent member does not need to be transparent to UV light. If the optically transparent member does not need to be transparent to UV light, the optically transparent member may be made of a material that transmits more than 80% of light having a wavelength between 400 and 700 nm (i.e., visible light), such as glass or borosilicate. That is, if there is no need to transmit UV light, the optically transparent member 150 still needs to transmit visible light. The optically transparent member 150 can be made of a material that transmits more than 50% of the wavelengths of light used by the camera 136 to monitor the shape of the superstrate 108 while it is held by the superstrate chuck assembly 118 during the planarization method.

[0038] 3C, 3D, 3E, and 6A-6G, the superstraight chuck assembly 118 may include a chamber 152 (space) defined by the superstraight holding member 130, the superstraight 108, and the optically transparent member 150. More specifically, the bottom surface of the optically transparent member 150, the top surface and outer edge of the superstraight 108, and the top surface of the superstraight holding member 130 are spaced apart to define the chamber 152. The chamber 152 may be further defined by an inner wall of a rigid member 188, which will be described below. As can be seen from FIGS. 3C, 3D, and 3E, the superstraight chuck assembly 118 may further include a fluid path 154 communicating with the chamber 152 to pressurize the chamber 152 and provide heat to the superstraight 108. As used herein, pressurization includes both positive and negative pressure.

[0039] The fluid pathway 154 can also be used to vent the chamber 152 to the atmosphere. The fluid pathway 154 can include components that both allow the chamber 152 to be selectively pressurized positively or negatively. In the illustrated example, the fluid pathway 154 includes a first port 156 connectable to the gas source 114. The gas in the gas source 114 can be heated using a heater 116. The heater heats the gas to a predetermined temperature, as described in more detail below. The gas in the gas source 114 can be clean, dry air, nitrogen, helium, neon, argon, or a mixture thereof. The heater 116 can be a gas line heater, a gas heater tank, an electric heating element, a fabric-type heater, or other system for heating gas. The introduction of gas from the gas source 114 into the chamber 152 can be controlled by a gas supply valve 174, which pressurizes the chamber 152 when the superstrate 108 is held by the superstrate chuck assembly 118 and is controlled by the processor 140. Since the gas introduced into the chamber 152 has already been heated to a predetermined temperature via the heater 116, the introduction of the gas into the chamber 152 also heats the superstrate 108.

[0040] The first port 156 may be connected to the pressurized / gas source 114, for example, via a gas supply line 166. The first port 156 is in communication with the gas supply line 166 and includes a first passage 158 in communication with a second passage 160. A first end 162 of the second passage 160 connects to the first passage 158, and a second end 164 of the second passage 160 connects to the chamber 152. Thus, when the first port 156 is connected to the pressurized / gas source 114, a positive pressure may be applied to pressurize the chamber 152 via the first fluid path 154. Furthermore, because the gas in the gas source 114 is heated to a predetermined temperature, the gas used to pressurize the chamber 152 also heats the superstrate 108. One or more additional fluid paths having the same structure as the fluid path 154 described above may also be implemented. For example, as best seen in FIG. 3C , an additional fluid path 155 having the same structure as the fluid path 154 may be positioned diametrically opposite the fluid path 154. Additional fluid path 155 may function to provide an outlet flow path for gas supplied by gas source 114 and may include a gas outlet valve 176 controlled by processor 140. That is, when gas outlet valve 176 is open, gas may enter chamber 152 and then flow out additional fluid path 155. Thus, fluid path 154 may be referred to as a first fluid path or an inlet fluid path, while additional fluid path 155 may be referred to as a second fluid path or an outlet fluid path. When only one fluid path 154 is present, it is both an inlet and an outlet fluid path.

[0041] The superstrate may be retained by the flexible portion 134 by reducing the pressure within the cavity 148. One method for reducing the pressure within the cavity 148 is to apply a vacuum to the cavity 148. To provide a vacuum to the cavity 148 of the superstrate retaining member 130, the superstrate chuck assembly 118 may further include a vacuum path in communication with the cavity 148. If a pressure differential already exists within the assembly relative to the atmosphere surrounding the assembly, the vacuum path may be used as a method for reducing the pressure within the cavity 148 without being coupled to a vacuum. The vacuum path may include components that allow the cavity 148 to apply a vacuum to the superstrate 108. The vacuum path includes a second port 168 connectable to a vacuum source (not shown) and a routing tube 170 connecting the second port 168 to the cavity 148. The second port 168 may be connected to the vacuum source, for example, via a vacuum supply tube (not shown). The routing tube 170 may be a flexible tube having a first end 180 connected to the second port 168 and a second end 182 connected to a fitting 184, such as a pneumatic fitting. The fitting 184 also connects to a through-hole formed through the flexible portion 134 of the superstrate retention member 130 and leading to the cavity 148. That is, the fitting 184 is connected to both the routing tube 170 and the through-hole, thereby directing vacuum suction downward into the cavity 148 through the through-hole. Thus, when the second port 168 is connected to a vacuum source, a vacuum may be applied to the cavity 148 to provide a suction force that can couple the region of the superstrate 108 below the cavity 148 with the flexible portion 134. Further details for applying a vacuum to the cavity 148 are described in U.S. Pat. No. 11,728,203.

[0042] One or more additional vacuum paths having the same structure as the vacuum paths discussed above can be implemented, with each vacuum path communicating with the same cavity 148 and / or with a corresponding additional cavity (not shown) formed in the superstrate retention member 130. The additional cavities may be concentrically disposed around the cavity 148. That is, the additional cavities may also be concentrically disposed around the central opening 132, but may be disposed at a greater radial distance from the inner edge 133 than the illustrated cavity 148. In one embodiment, the inner diameter of the superstrate retention member 130 may be smaller, and / or the cavity 148 may have an additional land 226. For example, an additional vacuum path having the same structure as the vacuum path discussed above may be disposed diametrically opposite the aforementioned vacuum path. The additional cavities or vacuum cavities may be used to help separate the superstrate from the stiffening layer as part of a planarization process, which will be described in more detail below. In another embodiment, additional cavities or vacuum cavities allow the same superstrate chuck assembly 118 to be used for different size superstrates.

[0043] In another embodiment, the cavity 148 and vacuum path can be replaced with another mechanism for coupling the superstrate retention member 130 to the superstrate. For example, an electrode that applies an electrostatic force may be included instead of the cavity / vacuum configuration. Another option is a mechanical latch, where a mechanical structure on the underside of the superstrate retention member 130 is mateable (good, tight, and / or suitable) with the superstrate.

[0044] The superstrate chuck assembly 118 may further include a rigid member 188. The rigid member 188 does not need to be made of a transparent material that allows UV light to pass through. That is, the rigid member 188 may be composed of a material that is opaque to UV light. The rigid member 188 may be composed of a plastic (e.g., acrylic), glass (e.g., fused silica, borosilicate), metal (e.g., aluminum, stainless steel), or ceramic (e.g., zirconia, sapphire, alumina). In an exemplary embodiment, the rigid member 188 may be composed of the same material as the superstrate holding member 130.

[0045] FIG. 4 illustrates an exploded view in which the rigid member 188 is shown separated from the superstrate retention member 130 and the optically transparent member 150. As best seen in FIG. 4, the rigid member 188 may include a generally circular body 190 defining an open central region 192. The outer periphery of the rigid member 188 may be uniform. The inner periphery of the rigid member 188 may have a step 194 that provides a receiving surface 196 for receiving the optically transparent member 150. That is, as best seen in FIGS. 3D and 3E, the optically transparent member 150 may be positioned on the receiving surface 196 of the step 194, thereby covering the central region 192. The optically transparent member 150 may be secured onto the receiving surface 196, for example, by an adhesive. In this manner, when the optically transparent member 150 is placed / fixed on the receiving surface 196, the chamber 152 is defined by the lower surface of the optically transparent member, the inner surface of the rigid member 188 (more specifically, the inner surface of the step 194), the upper surface of the superstrate retaining member 130, and the superstrate 108.

[0046] The superstrate retaining member 130 may be coupled to the underside of the rigid member 188 using coupling members (not shown), such as screws, nuts / bolts, adhesive, or the like. The coupling members may be positioned adjacent the outer edge 191 of the rigid member 188 and adjacent the outer edge 131 of the superstrate retaining member 130. If the coupling members are screws, the coupling members preferably pass through the superstrate retaining member 130 adjacent the outer edge 131 and into the rigid member 188 adjacent the outer edge 191, for example, through a plurality of receiving holes 189 (FIGS. 3E, 4). If the coupling members are adhesive, the coupling members are preferably located between the superstrate retaining member 130 adjacent the outer edge 131 and the rigid member 188 adjacent the outer edge 191. In this manner, the upper surface of the superstrate retaining member 130 is fixed in contact with the outer edge 131 and the lower surface of the circular body 190 of the rigid member 188 adjacent the outer edge 191. The additional surface area of ​​the superstrate retaining member 130 can be selectively bonded to the rigid member 188 as part of the planarization process. Methods for selectively bonding the additional surface area of ​​the superstrate retaining member 130 to the rigid member 188 are described in more detail below.

[0047] As shown in FIGS. 3C, 3D, and 3E, all or a portion of the fluid path 154 and / or the additional fluid path 155 described above may be contained within the rigid member 188. Similarly, all or a portion of the vacuum path and / or the additional vacuum path communicating with the cavity 148 may be included within the rigid member 188. More specifically, a portion of the first port 156, a portion of the first passage 158, the second passage 160, the first end 162, and the second end 164 of the fluid path 154 may be contained within the rigid member 188. A portion of the second port 168 of the vacuum path may be contained within the rigid member 188, among other paths not shown. However, as best shown in FIGS. 3C and 4, the routing tube 170 may be external to the rigid member 188. Thus, in addition to supporting the optically transparent member 150 and the superstrate retention member 130, the rigid member 188 may also provide paths / structures for the fluid and vacuum paths. In an alternative embodiment, the routing tube 170 is not present and the vacuum passes through a port in the rigid member 188, through a channel from the non-flexible portion of the superstrate retaining member 130 to the flexible portion 134 of the superstrate retaining member 130, and to the cavity 148.

[0048] The superstrate chuck assembly 118 may further include an additional vacuum passage that allows the superstrate holding member 130 to be selectively secured to the lower surface of the rigid member 188. While the vacuum passages described above communicate with the cavity 148 of the superstrate holding member 130, an additional vacuum passage that allows the superstrate holding member 130 to be selectively secured to the lower surface of the rigid member 188 is an annular cavity within the rigid member 188 that opens onto the lower surface of the rigid member 188. Details of these additional vacuum passages are described in U.S. Pat. No. 11,728,203. The additional vacuum passages may include components that together apply a vacuum suction force to the upper surface of the superstrate holding member 130 to further secure the superstrate holding member 130 to the lower surface of the rigid member 188. The additional vacuum passage may include a port 204 that is connectable to a vacuum source (not shown). The port 204 of the vacuum passage 200 may be connected to the vacuum source via, for example, a vacuum tube (not shown). The port 204 of the vacuum path communicates with the annular cavity 212, which has an open end facing downward toward the superstrate retention member 130. Therefore, when the port 204 of the vacuum path is connected to a vacuum source and the upper surface of the superstrate retention member 130 is in contact with the lower surface of the rigid member 188, a vacuum can be applied to the annular cavity 212 to secure the superstrate retention member 130 to the rigid member 188. Additional vacuum paths communicate with additional annular cavities 222 and 224, each having an open end facing downward toward the superstrate retention member 130. The additional annular cavities may be radially spaced apart. Thus, a vacuum can be selectively applied to the annular cavities 212, 222, and 224. Details of selectively applying a vacuum to the annular cavities are described in U.S. Pat. No. 11,728,203.

[0049] While the exemplary embodiment of the superstrate chuck assembly 118 includes the rigid member 188 as a structural element separate from the superstrate retaining member 130, in another exemplary embodiment, the rigid member may be a single piece of structure including a portion shaped like the flexible portion of the superstrate retaining member and a portion shaped like the rigid member. In other words, in such an embodiment, there is no separate rigid member; instead, there is a single continuous structure having thick portions resembling the rigid member and thin portions resembling the flexible portion. In such an embodiment, because there is no separate rigid member ring and superstrate retaining member, there is no need for an annular cavity, or for ports and cavities providing a vacuum path to the annular cavity. Rather, in this embodiment, there will only be fluid path(s) and possibly vacuum path(s) (i.e., equivalent to fluid path 154) leading to chamber 152, and possibly a vacuum path (i.e., equivalent to the vacuum path communicating with cavity 148) leading to the flexible portion of the member.

[0050] The operation of the superstraight chuck assembly 118 as part of a planarization process will now be described with reference to FIGS. 5-6L. FIG. 5 shows a flow chart of a planarization method 500. FIGS. 6A-6L show cross-sectional schematic diagrams of a planarization method 500 using the superstraight chuck assembly 118. For simplicity, the schematic diagrams of FIGS. 6A-6L omit cavities 212, 222, and 224, among others. FIGS. 7(a) and (b) are timing diagrams of valve states. FIGS. 7(c)-(h) are timing diagrams showing the temperatures of each component of the planarization system 100 at different times during the planarization method 500.

[0051] The method begins at step S502, in which a substrate 102 having a droplet of moldable material 124 dispensed thereon is positioned beneath a superstrate 108 coupled with a superstrate holding member 130 of a superstrate chuck assembly 118. Thus, prior to performing step S502, a droplet of moldable material is dispensed onto the substrate in the manner described above. This moment is illustrated in FIG. 6A, which shows a schematic cross-section of a substrate 102 having dispensed moldable material 124 disposed beneath a superstrate 108 held by a superstrate chuck assembly 118.

[0052] Prior to performing step S502, the superstraight chuck assembly 118 is prepared by applying a vacuum to the cavity 148 of the superstraight holding member 130, contacting the cavity 148 with the upper surface of the superstraight 108, thereby coupling the superstraight 108 to the superstraight holding member 130. If there are multiple vacuum cavities (e.g., two) within the flexible portion 134 of the superstraight holding member 130, in one embodiment, less than all of the vacuum cavities (e.g., only one) have a vacuum applied during step S502. For example, in one embodiment, only the cavity radially outermost relative to the central opening 132 has a vacuum applied. However, in another embodiment, all of the vacuum cavities (e.g., two) may have a vacuum applied during step S502.

[0053] As shown in FIG. 6A , when the substrate 102 is placed under the superstrate 108, the chamber 152 may not yet be pressurized with a positive pressure or have heated gas flowing into it. In one embodiment, the gas supply valve 174 between the heater 116 and the chamber 152 may be closed (as indicated by the black triangle) and the gas outlet valve 176 may be open (as indicated by the white triangle). In another embodiment, to improve throughput, the chamber 152 may be preemptively pressurized with a positive pressure by introducing heated gas into the chamber 152 before the substrate 102 is placed under the superstrate 108 (this may require opening the gas supply valve 174 and, in some cases, the gas outlet valve 176). At the moment shown in FIG. 6A , the pressure P in the chamber is preferably equal to ambient pressure, e.g., atmospheric pressure, but may be positively or negatively pressurized, as controlled by the gas supply valve 174 and the gas outlet valve 176. The instant shown in Figure 6A serves as the starting point, or zero point, with respect to time on the timing diagrams of Figures 7(a)-(h). Each timing diagram shown in Figures 7(a)-7(h) illustrates the valve state and temperature of a different aspect of planarization system 100 over the same period of time. That is, the same point on the x-axis across all timing diagrams illustrates the corresponding temperature of each component at that same instant. As shown in Figure 6A, there is no heated gas flowing into or out of chamber 152 yet.

[0054] 7(a) is a valve state diagram of the gas supply valve 174, showing the open / closed state of the gas supply valve 174. FIG. 7(b) is a valve state diagram of the gas outlet valve 176, showing the open / closed state of the gas outlet valve 176. FIG. 7(c) is a valve state diagram of the gas outlet valve 176, showing the open / closed state of the gas outlet valve 176. C 7(d) is a timing diagram of the temperature of the superstrate 108. The temperatures discussed herein with respect to the temperature of the gas are the average temperature over the volume of the gas in the space between the superstrate chuck assembly 118 and the superstrate 108. S1 is a timing diagram of the superstrate temperature T discussed herein with respect to the temperature of the superstrate 108. S is the average temperature of the superstrate 108. FIG. 7(e) shows the temperature T F 7(f) is a timing diagram showing the temperature of the substrate 102. The temperatures discussed herein with respect to the temperature of the moldable material 124 and the moldable material film 144 are average temperatures over the volume of the moldable material. SUB 7(g) shows the temperature T of the substrate chuck 104. The temperatures discussed herein with respect to the temperature of the substrate 102 are average temperatures over the volume of the substrate. CHUCK 7(h) is a timing diagram of the temperature T STAGE 1 is a timing diagram of the substrate positioning stage 106. The temperatures discussed herein with respect to the temperature of the substrate positioning stage 106 are the highest measured temperatures at a particular time, measured across the entire volume of the substrate positioning stage 106. In other words, different portions of the substrate positioning stage 106 may have different temperatures at a particular time. Temperature T STAGE is the temperature at the point where the measured temperature is the highest.

[0055] At the instant shown in FIG. 6A, the chamber temperature T C , superstrate temperature T S , moldable material temperature T F , substrate temperature T SUB , substrate chuck temperature T CHUCK , and the substrate positioning stage temperature T STAGE are all approximately equal to their local ambient temperatures. Figures 7(c)-(h) reflect that each of these elements begins at a similar starting temperature prior to the introduction of the heated gas.

[0056] The method then proceeds to step S504, where the superstrate 108 is heated and curved by introducing a heated gas having a predetermined temperature into a chamber defined by the superstrate chuck assembly and the superstrate (i.e., into chamber 152). Step S504 may include several substeps. FIG. 6B shows a schematic cross-sectional view of the superstrate chuck assembly in a first substep when heated gas 172 is introduced into chamber 152. As shown in FIG. 6B, during this step, heated gas 172 may be controlled to flow from gas source 114 through open gas supply valve 174 and inlet fluid path 154 into chamber 152 and out through outlet fluid path 155 and open gas outlet valve 174. The heated gas in gas source 114 is maintained at a predetermined temperature using heater 116. The heated gas is introduced into chamber 152 at a specific pressure. As the gas exits the chamber 152 through the outlet passage 155, the heated gas may heat the superstrate at this point, but will not significantly increase the pressure within the chamber and cause the superstrate 108 to bend. The heated gas may be introduced at a flow rate of less than 10 liters per minute (LPM). That is, as shown in FIG. 6B, the pressure within the chamber 152 remains low enough that the superstrate 108 does not substantially bend. The flow of the heated gas through the outlet passage 155 may be controlled by the gas outlet valve 176 within the outlet passage 155. The chamber temperature T C almost immediately rises to the temperature of the heated gas supplied to chamber 152.

[0057] FIG. 6C shows a schematic cross-sectional view of the superstrate chuck assembly 118 after the moment shown in FIG. 6B during the second substep, when sufficient pressure has built up in the chamber 152 to bend the superstrate 108. At the moment shown in FIG. 6C, heated gas 172 continues to be introduced into the chamber 152 to compensate for any leakage. At the same time, the flow of heated gas 172 is prevented from flowing through the chamber 152 via the outlet passage 155. The flow can be prevented by closing the gas outlet valve 176 in the outlet passage 155. As the heated gas continues to flow into the chamber 152, the pressure in the chamber 152 continues to increase. The increased pressure in the chamber 152 causes the superstrate 108 to bend. At the same time, the superstrate 108 may move downward toward the moldable material 124 on the substrate 102, and / or the substrate 102 carrying the moldable material 124 may rise toward the superstrate 108. During this time, the superstrate 108 continues to bend further as pressure continues to build within the chamber 152 and the superstrate 108, and continues to be heated by the heated gas.

[0058] The timing diagrams of Figures 7(c)-(h) show the temperature changes that occur between the moment shown in Figure 6B, when the heated gas is first introduced, and the moment shown in Figure 6C, when the superstrate 108 is heated and bent.

[0059] As shown in FIG. 7(c), the heated gas is introduced into the chamber 152 and heated to a constant temperature T C The gas temperature T C The temperature T of the superstrate 108 can be 70°C to 120°C. S begins to rise upon introduction of the heated gas and continues to rise until the moment shown in FIG. 6C is reached. In an exemplary embodiment, the superstrate temperature T S The temperature T S The temperature rises from 0°C to 47°C from the moment of Figure 6B to the moment of Figure 6C, and the superstrate temperature TS can be between 23°C and 70°C at the moment of Figure 6C.

[0060] As shown in Figure 7(e) to (h), the moldable material temperature T F , substrate temperature T SUB , substrate chuck temperature T CHUCK , and the substrate positioning stage temperature T STAGE is the superstrate temperature T S begins to rise due to convection and then begins to rise slightly because front surface 108b becomes hotter and as front surface 108b approaches moldable material 124, heat begins to transfer to moldable material 124, but relatively slowly until contact is initiated.

[0061] FIG. 6D is a schematic cross-sectional view of the superstrate chuck assembly 118 in the third substep when sufficient pressure has further accumulated in the chamber 152 to further bend the superstrate 108, as compared to the moment shown in FIG. 6C. That is, the pressure in the chamber 152 at the moment shown in FIG. 6D is greater than the pressure in the chamber 152 at the moment shown in FIG. 6C. Furthermore, the superstrate 108 is significantly more bent at the moment shown in FIG. 6D than at the moment shown in FIG. 6C. The pressure in the chamber 152 at the moment shown in FIG. 6D is greater than the pressure in the chamber 152 at the moment shown in FIG. 6C. At the moment shown in FIG. 6D, heated gas continues to be introduced into the chamber 152. At the same time, the flow of heated gas is still prevented from exiting the chamber 152 through the outlet passage 155 by the closed gas outlet valve 176. As the heated gas continues to flow into the chamber 152, the pressure in the chamber 152 continues to increase. The increased pressure in the chamber 152 causes the superstrate 108 to further bend. At the moment shown in Figure 6D, the superstrate 108 moves downward toward the moldable material 124 on the substrate 102, and / or the substrate 102 carrying the moldable material 124 is raised toward the superstrate 108 so that the superstrate 108 nearly contacts the moldable material. During this time, the pressure continues to build in the chamber 152, and as the heated gas continues to heat the superstrate 108, the superstrate 108 continues to bend further. That is, as shown in Figures 7(d)-(h), the temperatures of all of the above-mentioned components continue to increase, but only slightly.

[0062] The method then proceeds to step S506, where the moldable material 124 is heated and flattened by contact with the heated, curved superstrate 108. Step S506 is illustrated in FIGS. 6E-6G. FIG. 6E shows a schematic cross-sectional view of the superstrate chuck assembly 118 at the moment when the heated, curved superstrate 108 contacts the moldable material 124 and begins to form the moldable material film 144. As shown in FIG. 6E, the chamber 152 remains pressurized with the heated gas 172 previously introduced into the chamber 152. A vacuum continues to be applied to the cavity 148. In one embodiment, the pressure P within the chamber 152 increases as the superstrate 108 conforms to the moldable material 124 to maintain the desired curvature. Applicant has determined that as the mismatch area of ​​the superstrate decreases, more pressure is often required to maintain a particular superstrate curvature. As the contact area of ​​the superstrate increases during step S506, the contact region of the superstrate begins to conform to the shape of the substrate below the contact region, while the portion of the superstrate outside the contact region is a non-conforming region where curvature must be controlled. Maintaining this curvature is important to minimize gas entrapment, which can lead to unfilled defects. In one embodiment, the curvature just beyond the conforming portion of the superstrate (the contact region) is controlled. In other words, the curvature of the superstrate in an annular region just outside the contact region is controlled. In one embodiment, the desired superstrate curvature profile in this annular region is controlled while the moldable material spreads below the contact region. This may require maintaining and / or increasing the pressure P in step S506. In one embodiment, after the moldable material 124 stops spreading, the superstrate 108 is “flat” (conforming to the shape of the substrate 102).

[0063] When the heated, curved superstrate 108 contacts the moldable material, in addition to flattening to form the moldable material film 144, heat is further transferred from the superstrate 108 to the moldable material film 144. That is, because the superstrate 108 has been heated via the heated gas 172 introduced into the chamber 152, and because the moldable material 124 is at a lower temperature prior to step S506, upon contact between the superstrate 108 and the moldable material 124, at the moment shown in FIG. 6E, the moldable material 124 continues to heat as it is simultaneously flattened into the moldable material film 144. More specifically, the front (bottom) surface 108b of the superstrate 108 continues to transfer heat to the moldable material 124, among other components. After the moment shown in FIG. 6E, the chamber temperature T C and superstrate temperature T S decreases as heat is transferred from the superstrate 108 to the moldable material 124 and the material below.

[0064] FIG. 6F shows a schematic cross-sectional view of the superstrate chuck assembly 618 continuing to move downward toward the substrate 102 to further form the moldable material film 144. During this time, the heated and curved superstrate 108 continues to heat and flatten the moldable material 124 into the moldable material film 144. As seen in FIG. 6F, as the superstrate 108 continues to press downward, the moldable material film 144 of the moldable material 124 spreads further along the surface of the substrate 102 toward the outer edge. The positive pressure P is further increased or maintained to maintain the desired curvature of the region of the substrate that generally conforms to the moldable material. As the superstrate 108 continues to press downward toward the substrate 102, the superstrate 108 continues to curve to maintain the desired curvature of the region of the substrate that generally conforms to the moldable material. Thus, the superstrate 108 in FIG. 6F has less arc than in FIG. 6E, so that the region of the superstrate 108 that generally conforms to the moldable material maintains the desired curvature. Simultaneously, the flexible portion 134 also begins to flatten. Vacuum suction is still applied to cavity 148 in Figure 6F.

[0065] Further contact of the heated and curved superstrate 108 with the moldable material 124, in addition to further flattening into the moldable material film 144, also transfers heat from the superstrate 108 to the moldable material film 144 and the other components described above.

[0066] In an exemplary embodiment, the moldable material temperature T F , substrate temperature T SUB , substrate chuck temperature T CHUCK , and the substrate positioning stage temperature T STAGE As the temperature continues to increase from the moment in FIG. 6E to the moment in FIG. 6F, the chamber temperature T C and superstrate temperature T S continues to decline.

[0067] FIG. 6G shows a schematic cross-sectional view of the superstrate chuck assembly 118 at the point where the superstrate 108 is fully pressed against the moldable material 124 and the moldable material film 144 is fully formed. As shown in FIG. 6G, the superstrate 108 has been pressed until it is flat again. That is, the superstrate 108 no longer has an arc or is substantially devoid of an arc. Similarly, the flexible portion 134 of the superstrate holding member 130 is flat or is substantially devoid of a curve. As shown in FIG. 6G, the flow of heated gas from the gas source to the chamber 152 has been terminated. Vacuum suction is still applied to the cavity 148. Once the superstrate 108 is fully in contact with the moldable material film 144, the moldable material 124 is fully flattened onto the moldable material film 144, and the moldable material film 144 is fully heated.

[0068] In an exemplary embodiment, the moldable material temperature T F , substrate temperature T SUB , substrate chuck temperature T CHUCK , and the substrate positioning stage temperature T STAGE As the temperature continues to increase from the moment of FIG. 6F to the moment of FIG. 6G, the chamber temperature T C and superstrate temperature TS continues to decrease. As the contact area between the superstrate and the moldable material increases, the thermal conductivity and transfer of heat from the superstrate to the rest of the system also increases.

[0069] The predetermined temperature of the gas may be selected to increase the temperature of the moldable material by 5°C to 50°C from the start of the planarization process (i.e., before the moment of FIG. 6A) to the start of curing in step S508. The predetermined temperature of the gas may be selected to increase the temperature of the moldable material at the start of curing by 25°C to 80°C. As noted above, the predetermined temperature of the gas may be between 70°C and 120°C. The predetermined temperature of the gas may be 10 to 250% higher than the temperature of the moldable material before the superstrate is contacted with the moldable material.

[0070] The method then proceeds to step S508, where the formable material film 144 located between the superstrate 108 and the substrate 102 is cured. FIG. 6H shows a schematic cross-sectional view of the superstrate chuck assembly 118 when the superstrate 108 is initially released from the superstrate holding member 130. To release the superstrate 108, the vacuum applied to the cavity 148 is terminated. More specifically, because the superstrate 108 is in contact with the formable material film 144, cessation of the vacuum to the cavity 148 releases the multi-layer structure including the superstrate 108, the formable material film 144, and the substrate 102. The gas supply valve 174 may be opened at this point while the multi-layer structure (superstrate 108 / formable material film 144 / substrate 102) is beneath the superstrate chuck assembly 118. The multi-layer structure is supported by the substrate chuck 104. As shown in FIG. 6H, when the superstrate 108 / formable material film 144 / substrate 102 are released, the outlet channel 155 can be opened to allow the heated gas 172 to exit the chamber 152 through the outlet channel 155. Simultaneously, as also shown in FIG. 6H, because the superstrate 108 is no longer held by the superstrate holding member 130, the heated gas 172 also escapes through the opening between the superstrate holding member 130 and the superstrate 108. The multilayer structure (superstrate 108 / formable material film 144 / substrate 102) can be held under the superstrate chuck assembly 118 for a static spreading period lasting between 0.01 and 360 seconds. During the static spreading period, the multilayer structure (superstrate 108 / formable material film 144 / substrate 102) can be heated by hot gas supplied by the gas supply valve 174.

[0071] As shown in FIG. 7(c), as soon as heated gas is no longer introduced into chamber 152 (i.e., at the moment shown in FIG. 6E), the temperature T Sbegins to decrease. That is, after reaching the peak temperature, the heated gas is no longer introduced and the heat in the system begins to dissipate. Dissipation is small before contact but increases as the contact area between the superstrate and the moldable material increases. As shown in Figures 7(d)-(h), other components also experience temperature changes after the heated gas is no longer introduced. During differential heating, heat is transferred from the hotter areas of the system to cool parts of the system, depending on the thermal conductivity of the system. However, components farther from the heat source take longer to begin dissipating heat and change temperature.

[0072] At the moment shown in Figure 6H, the superstrate 108 / formable material film 144 / substrate 102 are released from the superstrate retention member 130, and the heated gas previously heating the superstrate 108 exits the chamber 152, whereupon the temperature of all components begins to rise as the heated gas is reintroduced by the gas supply valve 174. This continued increase in temperature is shown in Figures 7(c)-(h). As shown in Figures 7(d)-7(h), the temperature of each component continues to rise from the moment shown in Figure 6H until, at the moment shown in Figure 6I (curing), the temperature of the formable material reaches the target curing temperature T F (hardening begins).

[0073] Importantly, the maximum temperature of the substrate positioning stage 106 is limited to an upper limit of 27° C. (T STAGE, UL ) and the temperature of the substrate positioning stage remains below the temperature range (ΔT STAGE ) can be within a range of about 5°C. That is, the maximum temperature T shown in Figure 7(h) occurring between the moment of Figure 6G and the moment of Figure 6H STAGE is below 27°C when the ambient temperature is 23°C. Staying below this temperature prevents variations in planarization performance. Other approaches to heating the moldable material, such as heating the substrate with a heated substrate chuck, can increase the stage temperature by more than 5°C.

[0074] After the superstrate 108 is released from the superstrate holding member 130, following a static spread period, the superstrate 108 / formable material film 144 / substrate 102 / substrate chuck 104 may be moved to another location via the substrate positioning stage 106 for curing using a curing system (step S508). As shown in FIG. 6I, once the superstrate 108 / formable material film 144 / substrate 102 / substrate chuck 104 combination is in another location, a curing process may be performed. Curing may be performed by exposing the formable material film 144 to actinic radiation (e.g., UV light) that passes through the superstrate 108. However, because the superstrate 108 / formable material film 144 / substrate 102 / substrate chuck 104 combination is in a different location and is no longer coupled to the superstrate chuck assembly 118, the UV light does not need to pass through the optically transparent member 150 or the superstrate holding member 130. In this embodiment, the optically transparent member 150 may be made of a material that transmits more than 80% of light having a wavelength of 400-700 nm (i.e., visible light, not UV light) if the light does not pass through the optically transparent member, such as glass or borosilicate, but does not need to be made of a material that transmits UV light. After curing is complete, the superstrate 108 / planarization layer 146 / substrate 102 / substrate chuck 104 combination can be placed back under the superstrate chuck assembly 618. The UV irradiation hardens the moldable material film 144, thereby forming the planarization layer 146.

[0075] As mentioned above, FIGS. 7(c)-7(h) show the temperature of each component changing throughout the planarization process until the moment of curing shown in FIG. 6I. Importantly, ideally, the temperature of the formable material film 144 reaches a predetermined temperature at the start of curing. The predetermined temperature for curing the formable material is a temperature that avoids the above-mentioned problem; that is, when the temperature of the formable material is at a predetermined temperature at the time of curing determined based on the bake temperature, uneven topography on the surface of the baked layer is avoided or minimized. The predetermined temperature of the formable material at the start of curing can be 25°C-80°C, 40°C-70°C, or 50°C-60°C, depending on the formable material and the bake temperature during step S512. The predetermined temperature of the heated gas is selected by considering the time and dissipation of heat generated between the time the formable material is released from the chuck assembly (together with the substrate and superstrate) and the moment the formable material is cured. In other words, the predetermined temperature of the heated gas is selected so that the temperature of the moldable material temporarily rises to a higher temperature and then naturally decreases over the course of curing until it finally reaches the ideal curing temperature. The duration for which the gas supply valve 174 is open is also selected based on the heat dissipation of components in the system, experimentation, heat transport calculations, and / or simulation. This ideal curing temperature may be 217-304% higher than the baseline temperature of the moldable material before any heating (e.g., 23°C). The predetermined temperature of the gas may be selected to increase the temperature change of the moldable material 124 by 10%-250% from before contacting the superstrate (i.e., before the moment of FIG. 6E) to when it is cured (i.e., the moment of FIG. 6I). The predetermined temperature of the gas may be selected to increase the temperature change of the moldable material by 25°C-80°C from before contacting the superstrate to when it is cured. The predetermined temperature of the gas may be selected to increase the temperature of the moldable material during curing by 50°C-60°C.

[0076] In another embodiment, the curing process may be performed without moving the superstrate 108 / planarizing layer 146 / substrate 102 / substrate chuck 104 combination to another location after the superstrate 108 / planarizing layer 146 / substrate 102 / substrate chuck 104 combination is released from the superstrate holding member. That is, curing may occur with the superstrate 108 / planarizing layer 146 / substrate 102 / substrate chuck 104 combination in the same location as the superstrate chuck assembly 118, but at a distance below the superstrate chuck assembly 118. In this case, the radiation source 126 may, for example, emit actinic radiation (e.g., UV radiation) that is directed through the superstrate 108 through optically transparent members 150, each of which allows UV radiation to pass through. In one embodiment, the superstrate holding member 130 may be transparent to UV radiation. In embodiments in which UV radiation passes through the light-transmitting member, the light-transmitting member 150 may be constructed from a material that transmits more than 80% of light having wavelengths between 310 and 700 nm (i.e., UV light and visible light), such as sapphire or fused silica.

[0077] If curing occurs in-place with the chuck assembly, the temperatures of the top side of the superstrate, the bottom side of the substrate, the formable material, etc. during curing will be the same as those provided above when curing occurs in a separate cure location. However, because the formable material has less time to dissipate heat after being planarized into the formable material film 144, the temperature of the heated gas may be lower than when curing occurs in-place. For example, the heated gas may have a 5% lower temperature when curing occurs in-place compared to when curing occurs in a separate location.

[0078] The method then proceeds to step S510, where the superstrate 108 is separated from the planarization layer 146. FIG. 6J shows a schematic cross-section of the superstrate chuck assembly 118 over the superstrate 108 / planarization layer 146 / substrate 102 combination at the moment when the separation initiator 110 is extended upward to initiate separation between the superstrate 108 and the planarization layer 146. The substrate chuck 104 may include the separation initiator 110. In one embodiment, the separation initiator 110 may be a push pin. The separation initiator 110 may reside in a passage extending through the substrate chuck 104. The separation initiator 110 is configured to move upward. The separation initiator 110 may extend through a hole or notch in the substrate 102 and contact the underside of the superstrate 108. 6J, the separation initiator 110 can contact the underside of the superstrate 108 at the outer edge of the superstrate 108. The application of an upward force by the separation initiator to the underside of the superstrate 108 causes a small portion of the superstrate 108 to separate from the planarization layer 146. This initial separation at the outer edge also marks the start of separation between the superstrate 108 and the planarization layer 146.

[0079] With separation initiated, the superstrate 108 can then be recoupled with the superstrate holding member 130. FIG. 6K shows a schematic cross-sectional view of the superstrate chuck assembly 118 and the superstrate 108 / planarization layer 146 / substrate 102 combination at the moment when the superstrate 108 is recoupled with the superstrate holding member 130. As shown in FIG. 6K, a vacuum is again applied to the cavity 148, and the top surface of the superstrate 108 is coupled to the superstrate holding member 130. After the superstrate 108 is again coupled with the superstrate holding member 130, the separation can be propagated until complete separation of the superstrate 108 forming the planarization layer 146 is achieved. The separation can be propagated by lifting and / or rotating the superstrate chuck assembly 118 until complete separation is achieved. Detailed methods for separating the superstrate 108 from the planarization layer 146 are described in U.S. Patent Application Publication No. 2023 / 0095200, published March 30, 2023, which is incorporated herein by reference in its entirety. During this period, the gas outlet valve 176 may be open and the gas supply valve 174 may be closed.

[0080] FIG. 6L illustrates the moment immediately after the separation of step S510 is complete and the superstrate 108 is peeled off the planarization layer 146. After separation is complete, the superstrate chuck assembly 118 holds the superstrate 108, and the substrate 102 holds the planarization layer 146, as shown in FIG. 6L. The planarization method 500 can then begin again for another substrate by returning to the orientation shown in FIG. 6A. As described above, the planarization method 500 can be repeated many times, on the order of tens of thousands of times. When it is desirable to remove the superstrate 108 from the superstrate chuck assembly 118 (e.g., after a predetermined number of planarization processes are completed or if some other indicator suggests that the superstrate should be replaced), the vacuum applied to the vacuum cavity 148 can be released.

[0081] After the superstrate 108 is removed from the cured planarization layer, the substrate 102 with the cured planarization layer is removed from the substrate chuck 104. The substrate with the cured planarization layer may then be baked during a bake step S512. The bake step S512 may be performed in a bake module that is part of the planarization system 100 or in a separate bake tool. The bake step S512 is performed at a bake temperature and a bake soak time. The bake temperature in step S512 may be selected based on subsequent processing steps. The bake step S512 tends to increase the degree of polymerization of the cured planarization layer. The bake step S512 may also affect planarization performance as the baked layer shrinks relative to the cured planarization layer. Applicant has discovered that selecting the temperature at which curing begins based on the bake temperature can improve planarization performance after baking. Applicant has found it useful to store a cure temperature-bake temperature lookup table that contains the relationship between the cure temperature of the formable material at the start of curing and the bake temperature. This lookup table can be generated based on experimental performance in which various films are formed and baked at different temperatures. This lookup table can then be used to select the gas temperature of the heated gas supplied by heater 116. Processor 140 can receive the planned bake temperature and send instructions to heater 116 based on the cure temperature-bake temperature lookup table.

[0082] The embodiments described herein can be used to maintain closer to 0% thickness variation between the baked and pre-cured layers, or between the baked and cured layers, of a photocurable composition when compared to photocuring at ambient temperatures compared to photocuring at temperatures higher than ambient. A moderate photocuring temperature can allow 0% thickness variation to be achieved compared to photocuring at temperatures that are too low or too high. Better dimensional stability helps make the process more robust and repeatable from substrate to substrate and from production lot to production lot. The inventors have found that for each material, there is a photocuring thickness variation that depends on the photocuring temperature and a bake thickness variation that depends on the bake temperature. The inventors have found that it is possible to select one of the photocuring thickness variation and the bake thickness variation to be positive and the other negative, thereby providing an optimal thickness variation as close to zero as possible.

[0083] Further modifications and alternative embodiments of various aspects will be apparent to those skilled in the art upon consideration of this description. Accordingly, this description is to be construed as illustrative only. It is understood that the forms shown and described herein are to be construed as example embodiments. Elements and materials may be substituted for those illustrated and described herein, parts and processes may be reversed, and certain features may be utilized independently, all of which will be apparent to those skilled in the art after having the benefit of this description.

Claims

1. heating and bending the superstrate held by the superstrate chuck by introducing a gas having a predetermined temperature into a space defined by the superstrate chuck and the superstrate; heating and flattening the moldable material by contacting the heated and curved superstrate with the moldable material; the predetermined temperature of the gas is greater than the temperature of the moldable material prior to contacting the heated and curved superstrate with the moldable material; A planarization method comprising:

2. 2. The method of claim 1, wherein the predetermined temperature of the gas is selected such that the temperature change of the moldable material from before contacting the superstrate to the onset of curing is between 10 and 250%.

3. 2. The method of claim 1, wherein the predetermined temperature of the gas is selected such that the change in temperature of the moldable material from before contacting the superstrate to the onset of curing is between 2°C and 60°C.

4. 2. The method of claim 1, wherein the predetermined temperature of the gas is selected so that the temperature of the moldable material at the start of curing is between 25°C and 80°C.

5. 2. The planarization method according to claim 1, wherein the predetermined temperature of the gas is between 70°C and 120°C.

6. said heating of said superstrate includes heating a back surface of said superstrate; heat from the back surface of the superstrate is transferred to the front surface of the superstrate; the front surface of the superstrate faces the moldable material; 2. The planarization method according to claim 1.

7. 7. The method of claim 6, wherein the predetermined temperature of the gas is selected such that the temperature of the superstrate is between 50°C and 70°C when the superstrate contacts the moldable material.

8. releasing the superstrate from the superstrate chuck; further heating the superstrate with the gas or a second gas having a second predetermined temperature while the moldable material spreads between the superstrate and the substrate; and curing the moldable material; the predetermined temperature of the gas or the second predetermined temperature of the second gas is selected such that the temperature of the moldable material is between 25°C and 80°C at the start of curing; 2. The planarization method according to claim 1.

9. 2. The planarization method of claim 1, wherein the step of bending the superstrate by introducing a gas into the space includes pressurizing the space with the heated gas.

10. 10. The method of claim 9, wherein the pressure in the space increases as the superstrate is heated.

11. 10. The planarization method of claim 9, wherein pressurizing the space with the gas includes preventing the gas from exiting the space after being introduced into the space.

12. 10. The method of claim 1, wherein prior to bending the superstrate, the superstrate is first heated by introducing the gas into the space while maintaining a pressure in the space that is insufficient to cause the superstrate to bend.

13. 13. The planarization method of claim 12, wherein the pressure in the space is maintained by simultaneously introducing the gas into the space and evacuating the gas from the space.

14. 14. The planarization method of claim 13, wherein the gas is introduced into the space through an inlet port and the gas is exhausted from the space through an outlet port.

15. 2. The method of claim 1, wherein the introduction of the gas into the space is terminated before releasing the superstrate from the superstrate chuck.

16. 16. The planarization method of claim 15, wherein the gas is released from the space when the superstrate is released from the superstrate chuck.

17. 2. The planarization method of claim 1, wherein the gas is selected from the group consisting of clean dry air, nitrogen, helium, neon, and argon.

18. the moldable material is on a substrate carried by a stage; the stage reaches a maximum temperature during the planarization method; the stage has a minimum temperature during the planarization method; the difference between the maximum temperature and the minimum temperature is less than 5°C; 2. The planarization method according to claim 1.

19. a super straight chuck for holding the super straight; a space at least partially defined by the superstrate chuck; a gas source communicating with the space and configured to introduce gas having a predetermined temperature into the space; The predetermined temperature of the gas is 70°C to 120°C. A planarization system comprising:

20. 1. A method of manufacturing an article, comprising: Dispensing a formable material onto a substrate; heating and bending the superstrate held by the superstrate chuck by introducing a gas having a predetermined temperature into a space defined by the superstrate chuck and the superstrate; heating and flattening the moldable material by contacting the heated and curved superstrate with the moldable material, thereby forming a film of the moldable material between the superstrate and the substrate; curing the film of the moldable material to form a hardened layer between the superstrate and the substrate; separating the superstrate from the stiffening layer to form a planarization layer; baking the planarization layer on the substrate to form a baked planarization layer; and processing the baked planarization layer on the substrate to produce an article; the predetermined temperature of the gas is greater than the temperature of the moldable material prior to contacting the heated and curved superstrate with the moldable material; A method for manufacturing an article.

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