Planarization system and method

Abstract

To provide a planarization system that uses a super straight to form a layer of formable material on a substrate.SOLUTION: A super straight 18 has a first surface that contacts a formable material 34 when the super straight is stacked on a substrate 12 and a second surface opposite the first surface. A planarization system 10 has a first conductive portion at the second surface of the super straight and a second conductive portion at the side of the substrate. Both the first and second conductive portions are grounded during a separation process that separates the super straight from the formable material on the substrate.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This disclosure relates to substrate processing, and more particularly to nanoimprint lithography or surface planarization in semiconductor manufacturing. [Background technology]

[0002] Imprint and planarization techniques are useful in the manufacture of semiconductor devices. For example, the process of 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 the height variation of the substrate can increase as more layers are added. Height variations negatively affect the ability to add further layers to a multilayer substrate. Separately, the semiconductor substrate (e.g., silicon wafer) itself is not necessarily perfectly flat and may contain initial surface height variations (i.e., topography). One way to address this problem is to planarize the substrate between stacking processes. Various lithography patterning methods benefit from planar patterning. In ArF laser-based lithography, planarization improves depth of focus (DOF), critical dimension (CD), and critical dimension uniformity. In extreme ultraviolet lithography (EUV), planarization improves feature placement and DOF. In nanoimprint lithography (NIL), planarization improves feature filling and CD controllability after pattern transfer.

[0003] Planarization techniques, sometimes called inkjet-based adaptive planarization (IAP), involve dispensing a variable droplet pattern of polymerizable material between the substrate and a superstraight, where the droplet pattern changes according to the substrate topography. The superstraight is then brought into contact with the polymerizable material, and the material is polymerized on the substrate, after which the superstraight is removed. Improvements to nanoimprint lithography and planarization techniques, including IAP technology, are desired to improve wafer-wide processing, step-and-repeat processing, and semiconductor device manufacturing, for example. [Overview of the project]

[0004] A planarization or imprinting system is provided, comprising at least superstraights and a substrate with a formable material sandwiched between them. The superstraights have a first surface in contact with the formable material and a second surface opposite to the first surface. A first conductive portion is provided on the second surface of the superstraights. The substrate includes at least a second conductive portion. During a separation process to separate the superstraights from the substrate, both the first and second conductive portions are grounded. The first conductive portion may include a transparent conductive layer formed on the second surface of the superstraights before the formable material is imprinted. The first conductive portion may include a conductive layer placed on the second surface of the superstraights after the formable material has been UV exposed. The conductive layer may include a conductive superstraight chuck for holding the superstraights during the imprinting process. The first conductive portion may consist of chromium (Cr), tin nitride (TiN), or tin oxide (SnO2). The first conductive portion may be in the form of a film, sheet, or wire mesh made from, for example, stainless steel, aluminum, or other conductive material. In one embodiment, the conductive layer has a thickness of approximately 10 nm to approximately 15 nm.

[0005] The second conductive portion may include a substrate chuck made of a conductive material. The second conductive portion may also include a conductive layer formed on the substrate. The second conductive portion may also include a specially prepared conductive substrate chuck, such as one made of non-stoichiometric silicon carbide (SiC), for holding the substrate during the imprint process.

[0006] A method is provided which includes the steps of curing a moldable material sandwiched between a superstraight and a substrate, and separating the superstraight from the substrate, including the following steps: The back surface of the superstraight opposite to the surface in contact with the moldable material is grounded. The bottom surface of the substrate in contact with the substrate chuck is grounded. While both the back surface of the superstraight and the substrate are grounded, the steps of separating the superstraight from the substrate, i.e., moving the substrate away from the superstraight, are performed vertically until the electric field strength between the superstraight and the cured moldable material falls below a predetermined value. For example, to unload the substrate or the superstraight, or both, the superstraight and the substrate are moved laterally to move further away from each other. Surface discharge is performed while the superstraight is moved laterally relative to the substrate (or the substrate is moved relative to the superstraight).

[0007] A method is provided for reducing the electrostatic field during the separation process of separating a superstraight from a substrate. A first capacitor is introduced between the back surface of the superstraight and ground, where the back surface is the surface opposite to the surface in contact with the moldable material sandwiched between the superstraight and the substrate. A second capacitor is introduced between the substrate and ground. Both the second capacitor and a third capacitor formed between the superstraight and the moldable material during the separation process are connected to ground to form a closed-loop current including the first capacitor, the third capacitor, and the second capacitor connected in series. The method may further include separating the superstraight vertically from the substrate and moving the superstraight laterally relative to the substrate (or moving the substrate laterally relative to the superstraight) until the superstraight and the substrate are completely separated and the electric field between the superstraight and the substrate is reduced to a predetermined value. Before moving the superstraight laterally relative to the substrate, a surface discharge treatment may be performed. The first capacitor can be introduced by providing a conductive layer on the back surface of the superstraight and providing an electrical connection between the conductive layer and ground. Before performing the imprint process, a conductive layer may be formed on the back surface of the superstraight using a transparent material. After UV irradiation, a conductive layer may be formed on the back surface of the superstraight. During the separation process, a first capacitor may be introduced by providing a conductive superstraight chuck for holding the superstraight and an electrical connection between the conductive superstraight chuck and ground. A second capacitor may be introduced by providing a substrate made of a conductive material and an electrical connection between the substrate and ground. During the separation process, a first capacitor may be introduced by providing a conductive substrate chuck for holding the superstraight and an electrical connection between the conductive substrate chuck and ground.

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

[0009] To gain a more detailed understanding of the features and advantages of the present invention, a more specific description of the embodiments of the present invention can be obtained by referring to the embodiments shown in the accompanying drawings. However, it should be noted that the accompanying drawings only show typical embodiments of the present invention and should not be regarded as limiting the scope of the present invention. The present invention can recognize other equally effective embodiments.

[0010] [Figure 1] A diagram showing a planarization and / or imprint system.

[0011] [Figure 2A] A diagram showing a planarization and / or imprint process. [Figure 2B] A diagram showing a planarization and / or imprint process. [Figure 2C] A diagram showing a planarization and / or imprint process.

[0012] [Figure 3A] A diagram showing a supersubstrate and a substrate of an imprint system during an initial separation process. [Figure 3B] A diagram showing a supersubstrate and a substrate of an imprint system during an initial separation process. [Figure 3C] A diagram showing a supersubstrate and a substrate of an imprint system during an initial separation process.

[0013] [Figure 4] A diagram showing a supersubstrate and a substrate of an imprint system during a lateral separation process of an imprint process.

[0014] [Figure 5] A diagram showing conductive structures formed on both a superstrate and a substrate according to one embodiment.

[0015] [Figure 6A] A diagram showing the initial vertical separation between a substrate and a superstrate without grounding. [Figure 6B] A diagram showing the initial separation process between a substrate and a superstrate with grounding.

[0016] [Figure 7A] A diagram showing various stages of the lateral separation of a superstrate with respect to a substrate. [Figure 7B] A diagram showing various stages of the electric field distribution.

[0017] [Figure 8] A diagram showing the charge distribution when the substrate is conductive but includes insulating films on both sides of the substrate.

[0018] [Figure 9] A diagram showing the removal of surface charges by a grounded ion discharge source.

[0019] [Figure 10] A diagram showing an equivalent electrical capacitor corresponding to a sandwich structure of a superstrate, a formable material, and a substrate.

[0020] [Figure 11] A diagram showing an equivalent electrical circuit of the structure as shown in Figure 6B.

[0021] [Figure 12A] A diagram showing the results of partial and complete lateral separation of a superstrate and a substrate as shown in Figures 7A and 7B. <统一格式,将 替换为 , [Figure 12B] 替换为 [Figure 12B] , 替换为 , 替换为 ,

[0022] 替换为

[0022] ,以下是修改后的内容> [Figure 12B] A diagram showing the results of partial and complete lateral separation of a superstrate and a substrate as shown in Figures 7A and 7B.

[0022] [Figure 13] A graph of electric field strength as a function of the vertical distance to different layers.

[0023] [Figure 14] A graph of the electric field strength as a function of the vertical distance when the substrate and substrate chuck are considered to be conductive.

[0024] [Figure 15] This diagram illustrates a method for minimizing the electric field between the Superstraight and the substrate that occurs due to separation after the curing process.

[0025] Throughout the drawings, unless otherwise noted, the same reference numerals and letters are used to indicate similar features, elements, components, or parts of the illustrated embodiments. Furthermore, this disclosure is described in detail with reference to the drawings, but in relation to exemplary embodiments. It is intended that changes and modifications may be made to the exemplary embodiments described without departing from the true scope and spirit of the disclosure of subject matter as defined by the appended claims. [Modes for carrying out the invention]

[0026] Flattening system Figure 1 shows a nanoimprint and / or planarization system 10 in which an embodiment may be realized. System 10 may be used to planarize a substrate 12 or to form a relief pattern on the substrate 12. The substrate 12 may be coupled to a substrate chuck 14. As shown in the figure, the substrate chuck 14 is a vacuum chuck. However, the substrate chuck 14 may be any chuck, including but not limited to vacuum, pin type, groove type, electrostatic type, electromagnetic type, etc.

[0027] The substrate 12 and substrate chuck 14 may be further supported by a positioning stage 16. The stage 16 can provide translational and / or rotational motion along one or more of the x, y, z, θ, and φ axes. The stage 16, substrate 12, and substrate chuck 14 may be placed on a surface plate (not shown).

[0028] A superstraight 18, used to planarize the substrate, is positioned at a distance from the substrate 12. The superstraight is a flat, planar member. In an alternative embodiment, the superstraight 18 is a template 18. The template 18 includes a body having a first face and a second face, one of which has a mesa (also called a mold) extending toward the substrate 12. The mesa may have a molding surface 22 thereon. Alternatively, the template 18 may be formed without a mesa.

[0029] The template 18, i.e., the superstraight 18, and / or mold, may 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 / or similar materials. As shown in the illustration, the molded surface 22 may be planar or may include features defined by a plurality of spaced recesses and / or protrusions, but embodiments of the present invention are not limited to such configurations. The molded surface 22 can define any original pattern formed based on a pattern formed on the substrate 12. The molded surface 22 may be blank, i.e., without pattern features, in which case a flat surface can be formed on the substrate 12. In an alternative embodiment, when the molded surface 22 is the same area size as the substrate, layers can be formed over the entire substrate (e.g., full substrate treatment). In an alternative embodiment, when the molded surface 22 is smaller than the substrate, one layer can be formed on a portion of the substrate at a time, and this is repeated over the entire substrate (e.g., step-and-repeat treatment).

[0030] The superstraight 18 (template 18) can be coupled to a superstraight chuck 28 (template chuck 28). The superstraight chuck 28 can be configured as vacuum, pin type, groove type, electrostatic type, electromagnetic type, and / or other similar chuck types, but is not limited to these. Furthermore, the superstraight chuck 28 can be coupled to a head 30. The head 30 can be movably coupled to a bridge 36 such that the superstraight chuck 28, the head 30, and the template 18 are movable at least in the z-axis direction.

[0031] System 10 may further comprise a fluid dispensing system 32. The fluid dispensing system 32 may be used to deposit a moldable material 34 (e.g., a polymerizable material) onto the substrate 12. The moldable material 34 may be placed on the substrate 12 using techniques such as droplet dispensing, spin coating, immersion coating, chemical vapor deposition (CVD), physical vapor deposition (PVD), thin-film deposition, thick-film deposition, and / or similar. Depending on design considerations, the moldable material 34 may be placed on the substrate 12 before and / or after a desired volume is defined between the superstraight 18 (mold) and the substrate 12.

[0032] The fluid dispensing system 32 can use different technologies to dispense the moldable material 34. If the moldable material 34 is sprayable, it can be dispensed using an inkjet-type dispenser. For example, thermal inkjet, micro-electromechanical system (MEMS) based inkjet, valve jet, and piezoelectric inkjet are common technologies for dispensing sprayable liquids.

[0033] System 10 may further include a radiation source 38 that guides chemical energy along the path 42. The head 30 and stage 16 may be configured to position the template 18 and substrate 12 in overlap with the path 42. Similarly, the camera 58 may be positioned in overlap with the path 42. System 10 may be coordinated by a processor 54 that communicates with the stage 16, head 30, fluid dispensing system 32, radiation source 38, and / or camera 58, and operate according to a computer-readable program stored in memory 56.

[0034] The head 30, the stage 16, or both, vary the distance between the superstraight 18 (mold) and the substrate 12 to define a desired volume between them to be filled with the moldable material 34. For example, the head 30 may apply force to the template 18 so that the superstraight 18 is in contact with the moldable material 34. After the desired volume is filled with the moldable material 34, the radiation source 38 generates chemical energy (e.g., ultraviolet light) to solidify and / or crosslink the moldable material 34 to conform to the shape of the surface 44 of the substrate 12 and the surface 22 of the template 18, defining a layer formed on the substrate 12. Flattening process

[0035] Planarization and nanoimprinting processes include steps schematically shown in Figures 2A-2C. Figures 2A-2C illustrate the steps performed in a planarization system or nanoimprinting system 10 configured to perform planarization or nanoimprinting. As shown in Figure 2A, moldable material 34 in droplet form is dispensed onto a substrate 12. As previously mentioned, the substrate surface is known based on previous processing operations. Alternatively, the substrate surface has some topography, which can be measured using a surface topography device, AFM, SEM, or optical surface profiler based on optical interference effects such as the Zygo NewView 8200. The local volume density of the deposited moldable material 34 varies depending on the substrate topography and / or template topography. The superstraight 18 is then positioned to contact the moldable material 34. As used herein, the template and superstraight are used interchangeably to describe an object having a molded surface 22 that is brought into contact with the moldable material 34 to control the shape of the moldable material 34. When used herein, the template chuck 28 and the superstraight chuck 28 are interchangeable for holding the template 18 or the superstraight 18.

[0036] Figure 2B shows the post-contact process after the superstraight 18 has made full contact with the moldable material 34, but before the polymerization process begins. The superstraight 18 is equivalent to the template 18 in Figure 1 and may be substantially featureless (may include alignment or identification features) and substantially the same size and shape as the substrate (characteristic dimensions of the superstraight 18, such as the average diameter, may be at least 3% of the characteristic dimensions of the substrate 12). In an alternative embodiment, the superstraight 18 is the template 18, which is smaller than the substrate and may have a feature-bearing molding surface 22 used to form features in the cured layer 34''. When the superstraight 18 comes into contact with the moldable material 34, the droplets fuse to form a moldable material film 34' that fills the space between the superstraight 18 and the substrate 12. Preferably, the filling process is carried out in a consistent manner so as not to trap air bubbles between the superstraight 18 and the substrate 12, minimizing unfilled defects. Polymerization of the moldable material 34 The processing or curing may be initiated by chemical radiation (e.g., UV radiation). For example, the radiation source 38 in Figure 1 may provide chemical radiation to cure, solidify, and / or crosslink the moldable material film 34' and define the cured planarized layer 34'' or the cured layer 34'' containing the features on the substrate 12. Alternatively, curing of the moldable material film 34' may be initiated by using heat, pressure, chemical reactions, other types of radiation, or any combination thereof. After curing, once the cured layer (planarized layer) 34'' is formed, the superstraight 18 may be separated from it. Figure 2C shows the cured (planarized) layer 34'' on the substrate 12 after separation of the superstraight 18. Separation process

[0037] After curing, the Superstraight 18 (or template 18) and the planarization layer 34 (or cured layer 34) are separated from each other. As is well understood, when two different materials are in contact and then separated from each other, electric charge can be generated. For example, this occurs when a film of the first material is formed on the surface of the second material. Each of the first and second materials acquires a net charge of the same magnitude with opposite signs to each other. Charge separation can also be observed due to the triboelectric effect caused by friction between the two materials. Charge separation occurs due to the difference in the work functions of the two different materials. Charge separation can also occur for two surfaces of the same material having different work functions in regions with different physical or chemical conditions, such as mechanical stress or dopant concentration. Figure 3A shows the Superstraight 18 in contact with the moldable material 34, and the Superstraight 18 and the cured layer 34" are formed from different materials. As shown in Figure 3B, charge separation also occurs when the two materials, namely the Superstraight 18 and the cured layer 34", are in static contact. In this embodiment, only one contact between 18 and 34 is considered. The sign of the charge depends on the material of the contact surface. In one embodiment, charge 51 is positive and charge 52 is negative, while the superstraight 18 and hardened layer 34" are formed of a glass material, and are formed of a polymerization material, such as a photoresist, planarizing material, nanoimprint material, or other resist. In some situations, depending on the material of the superstraight 18 and hardened layer 34", charge 51 may be negative and charge 52 may be positive. Since charges 51 and 52 have the same magnitude (absolute value), the electric fields generated by the positive charge 51 and the negative charge 52 cancel each other out so that a zero electric field is produced outside the contact. This is similar to a charged planar capacitor where the electric field outside the capacitor is zero.

[0038] Charges generated and accumulated on two surfaces of different materials can partially withstand the rapid separation of these two materials. The motion of the charges depends strongly on the properties of the materials and the dynamics of the separation. During separation, most of the charge dissipates through discharge processes, including surface conductance along the separation interface and electrostatic discharge through a gap filled with air or gas. The final level of charge value is formed by the lowest ionization threshold of the air or gas filling the space. The charge can be reduced to a level that cannot be easily dissipated through known mechanisms. The remaining charge forms a high electric field that can attract dust particles, which may include different materials such as organic, dielectric, semiconductor, conductive, oxide, metallic, or other particles. These particles steadily accumulate over time on the imprint and planarization tool surfaces. Laminar airflow inside the imprint and planarization tools can keep the particles low. However, the electric field can cause particles to move, jump, or be attracted to the charged working surfaces of the superstraight and substrate.

[0039] Figure 3C illustrates the separation performed by moving the superstraight 18 away from the substrate 12, or by moving the substrate 12 away from the superstraight 18. This separation creates an electric field in the gap between the superstraight 18 and the molding material layer 34 (substrate 12) due to charges 51 and 52. TIFF2023177248000002.tif77 may occur. Due to this separation, static charge may be generated at the contact surface between the superstraight 18 and the molding material film 34''. When the spatial separation is slight, an electric field may be generated. TIFF2023177248000003.tif66 is contained within the gap between the superstraight 18 and the moldable material 34. The superstraight 18 and the moldable material 34 behave similarly to an ideal flat capacitor, where the electric field exists only in the gap between the electrodes. Since the electric field is zero or near zero near the tip, particles outside the gap are not attracted.

[0040] As spatial separation increases, uncanceled charges can generate a macroscopic electric field outside the superstraight 18 and the moldable material 34 at a distance corresponding to the separation gap. For example, as shown in Figure 4, further separation between the superstraight 18 and the substrate 12 along the transverse direction can result in an electric field caused by charges 51A and 52A. TIFF2023177248000004.tif639 is generated. As shown in Figure 3C, the charges do not cancel each other out as in the case of a flat capacitor, but rather generate a macroscopic electric field. Experiments have shown that the electric field can easily reach 1 × 10⁻⁶. 6 It was found to exceed V / m. The dielectric strength of dry air is approximately 1.5 × 10⁻⁶. 6 V / m~approx. 3×10 6 The dielectric strength is V / m. The dielectric strength defines the electric field threshold at which plasma discharge begins. Discharge in air or other gases is possible during the separation of the superstraight and the substrate, including initial vertical separation followed by further lateral separation. If the electric field value is below the dielectric strength, the charge is stable. A stable charge, an uncanceled electric field, can cause problems with particle control within the imprint apparatus 10. Most dust particles are charged by frictional charging. Due to the electric field, charged particles can move to the charged superstraight and substrate, directly attracting or repelling them. In addition, pondermotive forces can push charged particles from high-electric-field areas to low-electric-field areas, thereby stirring the particles in the air.

[0041] To address the problem of moving charged particles being attracted to the charged surfaces of the superstraight and substrate, a conductive surface may be positioned or formed near the separation surfaces of the superstraight and substrate. Figure 5 shows an embodiment in which a conductive structure is incorporated near the superstraight and substrate. As shown, a conductive layer 53 is positioned on the upper part of the superstraight 18, opposite to the molded surface 22, and a conductive substrate chuck 14 is used to support the substrate 12. The conductive layer 53 may include a conductive film formed on the back surface of the superstraight 18. For example, the conductive film may be a metal film (chromium, Cr), or a conductive film of titanium nitride (TiN) or tin oxide (SnO) formed by vapor deposition or chemical vapor deposition, a metal plate, a metal mesh, or other structure. The thickness of the conductive layer 53 may be in the range of 10 nm to 15 nm. The conductive layer 53 may be temporarily or permanently positioned on the back surface of the superstraight 18 and removed during UV irradiation. The conductive layer 53 may be formed from a transparent conductive material and may be temporarily or permanently positioned on the back surface of the superstraight 18. Furthermore, the conductive substrate chuck 14 may be in the form of an intermediate conductive layer 64 that can be formed between the substrate 12 and the substrate chuck 14.

[0042] In Figure 6A, initial separation occurs along the vertical direction between the superstraight 18 on the substrate 12 and the hardened layer 34'', and as shown, charges 51 and 52 are generated, creating an electric field between the superstraight 18 and the hardened layer 34''. TIFF2023177248000005.tif54 exists. As shown in Figure 6A, the conductive structures may each be connected to ground via electrical paths 61 and 62. Each of the electrical paths 61 and 62 may include switches S1 and S2 for opening and closing the connection between the conductive structures 53 and 64 and ground, respectively. Alternatively, the electrical connection between ground and the conductive structures 53 and 64 may be permanent without using switches S1 and S2. Before grounding the conductive structures 53 and 64, for example, before closing switches S1 and S2, an electric field is established between the superstraight 18 and the moldable material 34. The file TIFF2023177248000006.tif54 is created.

[0043] Figure 6B shows the action of closing switches S1 and S2 to ground the conductive structures 53 and 64. In this case as well, the wires 53 and 64 can be connected without using switches S1 and S2 by using other electrical paths such as conductors. Grounding the conductive structure 53 causes charge 55 to appear on the back surface of the superstraight 18, and grounding the conductive structure 64 causes charge 60 to appear on the surface of the substrate chuck 14 due to charge redistribution. The substrate 12 can be considered as a non-conductive dielectric or a semi-conductive silicon wafer. The addition of charge creates an electric field. In addition to TIFF2023177248000007.tif66, the electric field in Super Straight 18. TIFF2023177248000008.tif66 and the electric field on substrate 12. The file TIFF2023177248000009.tif66 is generated.

[0044] Figures 7A-7B show various stages of lateral separation of the superstraight 18 relative to the substrate 12. As shown in Figure 7A, in the intermediate stage, an electric field is present in the overlapping region of charges 51 and 52. TIFF2023177248000010.tif66 exists, and outside the overlapping region, the electric field is zero or near zero. Figure 7B shows the positions of the superstraight 18 and substrate 12 when lateral separation is complete and charges 51 and 52 no longer overlap each other. The electric field between charges 51 and 52 is zero or near zero because there is no overlap between these charges. Charge 51 and charge 55 of the opposite sign in the superstraight 18 cancel each other out, and the electric field in the superstraight 18 is zero or nearly zero. Similarly, since the electric field in the substrate 12 is zero or nearly zero, charges 52 and 60 can cancel each other out.

[0045] In the embodiment shown in Figure 7B, a non-conductive substrate 12 is used for simplification. In actual applications, the substrate 12 may be conductive due to different levels of doping. However, the substrate 12 often contains an insulating film such as native silicon oxide (SiO2). Figure 8 shows the electric field distribution when the substrate 12 is conductive, but the surface of the substrate 12 contains an insulating film similar to SiO2. As shown, charges 57 and 67 are formed inside the conductive substrate 12. The addition of an additional layer of charge (double charge layer) does not modify the general method described with reference to Figures 7A and 7B.

[0046] In Figure 9, electrically grounded ion discharge power sources 63 and 64, such as an alpha-ionizer, X-ray or other ionization bar, may be positioned near the surfaces of the substrate 12 and the superstraight 18 to remove surface charges 51 and 52 after lateral separation is complete.

[0047] Figure 10 shows the electrically equivalent capacitor scheme corresponding to the sandwich structure of the superstraight 18, molding material 34”, and substrate 12”. Q i , C i , and V i Q is the initial charge, initial capacitance, and initial voltage at the time of initial separation between the Super Straight 18 and the molding material 34'', respectively. i The system remains stable even after initial separation and plasma discharge. Figure 11 shows the equivalent circuit of the structure shown in Figure 6B. As shown, a closed loop of the electrical circuit is formed by grounding the conductive structures 53 and 54. The electrical circuit includes capacitors C0, C1 and C2 connected in series. Initial charge Q i This is redistributed across three capacitors C0, C1, and C2. Since capacitors C1 and C2 are charged with the same current, the following equation holds: TIFF2023177248000011.tif1785 On the other hand, the voltage across the capacitor has the following relationship: V0 + V1 = V2(2). For example, the definition of the capacitor formula for each combination of charge, voltage, and capacitance can be used. Q0 = C0V0(3). Equation (2) can be rewritten as follows. Based on the above equation, the following relationship is obtained. TIFF2023177248000013.tif5987

[0048] As shown in Figure 3C, a typical value of the electric field measured by an electrostatic voltmeter after initial separation is about 10 6 V / m. This value is close to the discharge value in dry air of 1.5×10 6 V / m to 3×10 6 V / m. A higher electric field causes a discharge in air or gas until the value of the electric field is below the value required for self-sustaining plasma discharge. The initial separation distance between the super straight and the substrate in a typical imprint / flattening tool can be about 10 μm. Here, consider a substrate (wafer) and a super straight with a diameter of 300 mm. The substrate and the super straight are not connected to the ground. From the electric field strength, that is, E i = 10 6 V / m and the distance d = 10 μm, the initial voltage V i can be estimated. Thereby, the following initial voltage is obtained. V i = E i d i = 10 V Using the planar capacitor approximation of a 300 μm circular electrode with a 10 μm interval, the following equation is obtained. C i = 6.25×10 -8 F The initial charge Q i can be obtained using the following equation similar to Equation (3). Q i = 6.25×10 -7 C

[0049] As shown in Figure 6B, consider the situation where the conductive surface is grounded. Using equations (1) to (8), when the gap is 10 μm, Q0 = 6.11 × 10 -7 C, Q1 = Q2 = 1.38 × 10 -8 C, V0 = 9.8V, V1 = 4.3V, V2 = 5.5V. The same values ​​are obtained if the conductive surface is grounded before the initial separation between the superstraight and the substrate having an primordial charge. The charge is generated by the physical contact of different materials. Therefore, switches S1 and S2 can always be closed, leaving the conductive surface grounded. Alternatively, the conductive surface may always be grounded by simply connecting it to ground with a conductive wire. For a typical superstraight with a thickness of 700 μm, a diameter of 300 mm, and a dielectric constant of glass of 3.6, C1 = 3.2 × 10⁻⁶ -9 F can be calculated. Similarly, for a typical substrate with a thickness of 750 μm, a diameter of 300 mm, and a dielectric constant of approximately 3, C2 is approximately 2.51 × 10⁻¹⁰. -9 It is F.

[0050] Figures 12A and 12B show the result of complete lateral separation of the superstraight and the substrate, as shown in Figure 7B. In Figure 12A, as the spatial distance between the superstraight and the substrate increases, the distance between capacitors increases until capacitor C0 disappears, and the capacitance C0 decreases. When C0 = 0, equation (6) becomes as follows. Equation (7) of TIFF2023177248000014.tif1485 is transformed as follows: In accordance with TIFF2023177248000015.tif1174, Q i = 6.25 × 10 -7 C, C1 = 3.2 × 10 -9 F, V1 = 195 V, V2 = 250 V. Calculating the electric field within C1 and C2, E1 = 2.79 × 10⁻⁶ 5 V / m, E2 = 3.33 × 10 5The values ​​are V / m. All electric field values ​​are far from the dielectric breakdown of silicon and glass and are considered safe. The separation of the conductive structure from the grounded superstraight and the moldable material / substrate results in an initial low level of electric field and the absence of a significant electric field after separation. Figure 13 shows the electric field strength E0 in the space between the superstraight and the substrate, the electric field strength E1 inside the superstraight, and the electric field strength E2 in the space between the top surface of the substrate and the substrate chuck, as a function of vertical spacing. The substrate is assumed to be semi-insulating silicon (Si), i.e., a non-conductive structure. When the vertical spacing reaches 700 μm, the electric field strength E1 decreases to 200,000 V / m.

[0051] Figure 14 shows the electric field strength E0 in the space between the superstraight and the substrate, the electric field strength E1 inside the superstraight, and the electric field strength E2 in the space between the top surface of the substrate and the substrate chuck. The substrate and substrate chuck are assumed to be conductive. The substrate chuck has a 5% pin area with a pin height of 0.1 μm. When the vertical spacing reaches 700 μm, E1 decreases to 200,000 V / m.

[0052] Figure 15 is a flowchart of the separation process between the Superstraight and the substrate after the curing process. In step S1, the conductive structure is placed on the back surface of the Superstraight and the substrate. In step S2, the conductive structure is grounded. In step S3, the Superstraight and the substrate are separated vertically until the electric field between them falls below a predetermined value. In step S4, further separation between the Superstraight and the substrate is performed laterally. Next, in step S5, the surface charge is removed.

[0053] By considering this description, further modifications and alternative embodiments of various aspects will become apparent to those skilled in the art. Therefore, this specification should be construed as illustrative only. It should be understood that the forms shown and described herein should be construed as examples of embodiments. Elements and materials may be substituted with those illustrated and described herein, parts and processes may be reversed, and certain features may be used independently, all of which will become apparent to those skilled in the art after enjoying the benefits of this specification.

Claims

1. A planarization system for forming a layer of formable material on a substrate using a superstraight, wherein the superstraight has a first surface that contacts the formable material when the superstraight is laminated on the substrate, and a second surface opposite to the first surface, and the planarization system is The first conductive portion on the second surface of the superstraight, The second conductive portion on the substrate side, It has, A planarization system characterized in that, during a separation process for separating the superstraight from the moldable material on the substrate, both the first conductive portion and the second conductive portion are grounded.

2. The planarization system according to claim 1, characterized in that the first conductive portion includes a transparent conductive layer formed on the second surface of the superstraight before the moldable material is subjected to an imprinting process.

3. The planarization system according to claim 1, characterized in that the first conductive portion includes a conductive layer disposed on the second surface of the superstraight after the moldable material has been subjected to UV exposure.

4. The planarization system according to claim 1, characterized in that the first conductive portion includes a conductive superstraight chuck for holding the superstraight during the imprint process.

5. The first conductive portion is made of chromium (Cr), tin nitride (TiN), or tin oxide (SnO 2 The planarization system according to claim 1, characterized by comprising ).

6. The planarization system according to claim 1, characterized in that the first conductive portion includes a conductive layer in the form of a film, sheet, or wire mesh.

7. The planarization system according to claim 6, characterized in that the conductive layer has a thickness of about 10 nm to about 15 nm.

8. The planarization system according to claim 1, characterized in that the second conductive portion includes a substrate chuck made of a conductive material.

9. The planarization system according to claim 8, characterized in that the conductive material contains silicon carbide (SiC).

10. The planarization system according to claim 1, characterized in that the second conductive portion includes a conductive layer formed on the substrate.

11. The planarization system according to claim 1, characterized in that the second conductive portion includes a conductive substrate chuck for holding the substrate during the imprint process.

12. A process for curing the moldable material sandwiched between the Super Straight and the substrate, The process includes separating the superstraight from the substrate, The separation step is, A step of grounding the back surface of the super straight opposite to the surface that comes into contact with the moldable material, The steps include grounding the aforementioned substrate, While both the back surface of the superstraight and the substrate are in contact with the ground, the superstraight is moved vertically from the substrate until the electric field strength between the superstraight and the cured moldable material falls below a predetermined value. A step of further moving the superstraight from the substrate in the lateral direction, The process involves performing a surface discharge while the super straight is being moved in the lateral direction, A method characterized by having the following:

13. A method for reducing the electrostatic field during the separation process of separating a superstraight from a substrate, A first capacitor is introduced between the back surface of the superstraight and ground, where the back surface is the surface opposite to the surface that contacts the moldable material sandwiched between the superstraight and the substrate. A second capacitor is introduced between the substrate and the ground. The ground is connected to both the second capacitor and the third capacitor formed between the superstraight and the moldable material during the separation process, thereby forming a closed-loop current loop including the first capacitor, the third capacitor and the second capacitor connected in series. A method characterized by having the following:

14. In the separation process, the superstraight is separated vertically from the substrate until the superstraight and the substrate are completely separated and the electric field between the superstraight and the substrate is reduced to a predetermined value. The superstraight is moved laterally relative to the substrate. The method according to 13, further comprising the characteristic of having the above.

15. The method according to 14, further comprising performing a surface discharge treatment before moving the superstraight in the lateral direction relative to the substrate.

16. The method according to 14, characterized in that a conductive layer is provided on the back surface of the superstraight, and an electrical connection is made between the conductive layer and the ground, thereby introducing the first capacitor.

17. The method according to 16, further comprising forming the conductive layer with a transparent material on the back surface of the superstraight before performing the imprinting process.

18. The method according to 16, further comprising forming the conductive layer on the back surface of the superstraight after UV irradiation.

19. The method according to 13, characterized in that the first capacitor is introduced by providing a conductive superstraight chuck for holding the superstraight during the separation process, and an electrical connection between the conductive superstraight chuck and the ground.

20. The method according to 13, characterized in that the substrate is made of a conductive material, and the second capacitor is introduced by providing an electrical connection between the substrate and the ground.

21. The method according to 13, characterized in that a conductive layer is provided on the substrate and an electrical connection is made between the conductive layer and the ground to introduce the second capacitor.

22. The method according to 13, characterized in that the second capacitor is introduced by providing a conductive substrate chuck for holding the substrate during the separation process and an electrical connection between the conductive substrate chuck and the ground.

23. A system for forming a layer of moldable material on a substrate, A super straight chuck having a super straight chuck surface, A substrate chuck having a substrate chuck surface, The first conductive portion on the surface of the super straight chuck, The second conductive portion on the surface of the substrate chuck, It has, A system characterized in that both the first conductive portion and the second conductive portion are grounded during a separation process in which the super straight chuck and the substrate chuck move away from each other.

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