Flattening method and article manufacturing method

Abstract

To provide a technique advantageous for preventing dry contact in flattening processing.SOLUTION: A flattening method is provided for performing flattening processing of flattening a hardening material on a substrate by using super straight, repeatedly multiple times on the same surface of the substrate. The super straight is formed with a tapered surface that connects a side end surface and a flat surface forming a lower surface facing the substrate. In second flattening processing after first flattening processing, the hardening material is supplied so that an area of a hardened film formed below the tapered surface in the first flattening processing is covered by a liquid film formed in the second flattening processing.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a planarization method and a method for manufacturing an article. [Background technology]

[0002] As the demand for miniaturization of semiconductor devices increases, in addition to conventional photolithography technology, attention is being paid to microfabrication technology, in which uncured curable material on a substrate is molded and cured in a mold to form a pattern of the curable material on the substrate. This technology is called imprint technology, and it is possible to form a fine pattern on the order of several nanometers on the substrate.

[0003] One example of imprinting technology is the photocuring method. An imprinting device that uses the photocuring method forms a pattern on a substrate by using a mold to mold a photocurable material supplied to a shot area on the substrate, irradiating the material with light to harden it, and then separating the mold from the hardened material.

[0004] Furthermore, in recent years, a technique for planarizing a curable material on a substrate has been proposed (see Patent Document 1). The technique disclosed in Patent Document 1 aims to improve the accuracy of planarization by dropping a curable material based on steps on the substrate and curing the dropped curable material in a state where the flat surface of a mold is in contact with the dropped curable material.

[0005] The main items of planarization performance include flatness, film thickness, and defects, and these may become problems especially in the outer periphery of the planarization film. For example, if the amount of applied curable material is small or the applied area is narrow, the mold and the substrate may come into contact without the curable material, resulting in particles and defects, or the durability of the mold or substrate may be affected. In this way, the mold and the substrate may come into contact without the curable material. This is called dry contact. On the other hand, if the amount of applied curable material is large or the applied area is wide, the curable material may seep out from between the mold and the substrate. This seepage may reach the back side of the substrate and contaminate the device, the cured curable material may adhere to the mold during demolding and affect the planarization performance in the next and subsequent planarization processes, or the cured curable material may fall and cause defects.

[0006] As a measure to prevent such defects in the peripheral portion of the planarization film, there is a method of providing a taper on the outer periphery of the flat part of the mold (see Patent Documents 2 and 3). By providing a taper on the outer periphery of the flat part of the mold, even if the curable material seeps out from between the flat part of the mold and the substrate, the film thickness of the curable material increases at the tapered part, and the amount of spreading in the radial direction can be suppressed. On the other hand, if there is a shortage of curable material, dry contact occurs, so when a tapered mold is used, the curable material is supplied so that it seeps out from between the flat part of the mold and the substrate. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Special Publication No. 2011-529626 [Patent Document 2] JP 2020-4877 A [Patent Document 3] JP 2021-160352 A Summary of the Invention [Problem to be solved by the invention]

[0008] When planarizing a substrate with a planarization device, the desired flatness may not be obtained in one planarization due to the density and unevenness of the device pattern. In such a case, the planarization process can be performed multiple times to reduce the unevenness of the surface and improve the flatness. When the above-mentioned tapered mold is used, a raised portion formed by the taper occurs on the outer periphery of the planarization film. This raised portion exists within an area where the accuracy is not required, which is acceptable in general semiconductor processes, and is removed in a later process, so it does not pose a problem. However, when the same substrate is planarized multiple times, the raised portion generated in the previous planarization interferes with the mold during the second or subsequent planarization. Since the raised portion generated in the previous planarization has already been hardened, the interference is also a dry contact similar to the contact between the mold and the substrate without the hardening material as described above. Such dry contact may cause particles or defects, or may affect the durability of the mold or substrate.

[0009] The present invention provides an advantageous technique for preventing dry contact in planarization processes. [Means for solving the problem]

[0010] According to one aspect of the present invention, there is provided a planarization method that repeatedly performs a planarization process on the same surface of a substrate, the planarization process including a supplying step of supplying a curable material onto the substrate, a contacting step of contacting a superstrate with the curable material supplied onto the substrate to form a liquid film on the substrate, a forming step of curing the liquid film to form a cured film, and a separation step of separating the superstrate from the cured film, the planarization method being characterized in that the superstrate has a tapered surface that connects its side end surface to a flat surface that forms an underside facing the substrate, and in the supplying step in a second planarization process after a first planarization process, the curable material is supplied so that the region of the cured film formed under the tapered surface in the first planarization process is covered by the liquid film formed in the contacting step in the second planarization process. Effect of the Invention

[0011] According to the present invention, it is possible to provide an advantageous technique for preventing dry contact in a planarization process. [Brief description of the drawings]

[0012] [Figure 1] FIG. 2 is a diagram showing the configuration of a planarization apparatus. [Diagram 2] 1A and 1B are diagrams for explaining an outline of a flattening process; [Diagram 3] 11 is a flowchart showing a flattening process according to the embodiment. [Figure 4] 1A to 1C are diagrams illustrating dry contacts that occur when planarization processes are performed multiple times. [Diagram 5] FIG. 2 illustrates the appearance of a mold, substrate, and curable material during a planarization process. [Figure 6] FIG. 13 shows the state of the hardenable material at the spread end. [Figure 7] 1A to 1C are diagrams for explaining a planarization process performed multiple times without causing dry contact in an embodiment. [Figure 8] FIG. 2 illustrates the appearance of a mold, substrate, and curable material during a planarization process. [Figure 9] 13A and 13B are diagrams illustrating how dry contact is prevented. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, the embodiments will be described in detail with reference to the attached drawings. Note that the following embodiments do not limit the invention according to the claims. Although the embodiments describe a number of features, not all of these features are essential to the invention, and the features may be combined in any manner. Furthermore, in the attached drawings, the same reference numbers are used for the same or similar configurations, and duplicated descriptions are omitted.

[0014] First Embodiment 1 is a schematic diagram showing the configuration of a planarization apparatus 100 in an embodiment. The planarization apparatus 100 is realized as a molding apparatus that molds a curable material on a substrate 1 using a mold 11, and in this embodiment, the planarization apparatus 100 flattens the curable material on the substrate. The planarization apparatus 100 hardens the curable material on the substrate while the curable material is in contact with the mold, and forms a globally or locally flat surface of the curable material on the substrate by separating the hardened curable material from the mold.

[0015] The base material of the substrate 1 is typically a silicon wafer, but is not limited thereto. The substrate 1 may be selected from among those known as substrates for semiconductor devices, such as aluminum, titanium-tungsten alloy, aluminum-silicon alloy, aluminum-copper-silicon alloy, silicon oxide, and silicon nitride. The substrate 1 may be a substrate having an adhesion layer formed by surface treatment such as silane coupling treatment, silazane treatment, and formation of an organic thin film, thereby improving adhesion to the curable material. The substrate 1 is typically a circle having a diameter of 300 mm, but is not limited thereto.

[0016] As the mold 11, a mold made of a light-transmitting material is preferably used in consideration of the light irradiation process. Specific examples of the material constituting the mold include glass, quartz, light-transmitting resins such as PMMA (Polymethyl methacrylate) and polycarbonate resin, transparent metal deposition films, flexible films such as polydimethylsiloxane, photocured films, metal films, and the like. The mold 11 is preferably a circle with a diameter larger than 300 mm and smaller than 500 mm, but is not limited thereto. The diameter of the mold 11 may be preferably 200 to 400 mm. Furthermore, the thickness of the mold 11 is preferably not less than 0.25 mm and less than 2 mm, but is not limited to this.

[0017] In the case of an imprint apparatus, a pattern such as a circuit pattern is formed on the mold, but the mold 11 used in this planarization apparatus does not have such a pattern. The mold 11 is a mold with a flat surface. Such a mold having a flat surface used in a planarization apparatus is called a superstrate. Alternatively, such a mold is also called a pressing member, a flat plate, or the like.

[0018] As the curable material, a UV-curable liquid may be used in consideration of the light irradiation process. Typically, a monomer such as acrylate or methacrylate may be used.

[0019] In the EUV photolithography process, the depth of focus (hereinafter referred to as "DOF") of the projected image of the fine circuit pattern has become shallower in recent years as the NA has increased. In recent examples, the allowable DOF for an EUV lithography device with NA=0.33 is 300-110 nm (depending on the illumination mode). The allowable DOF for an EUV lithography device with NA=0.55 is 160-40 nm (depending on the illumination mode). However, it has been found that it is difficult to obtain sufficient surface flatness performance within such an allowable range with the conventional method of applying an SOC film using a spin coater. In particular, in the case of spin coating, a layer of uniform thickness is formed on the wafer due to the viscosity of the SOC coating agent dropped onto the substrate (wafer) and the centrifugal force caused by the spin. Therefore, when there is a long period in which the change in wiring density of the base pattern of the process wafer is 5 μm or more, the boundary where the wiring density changes will be highlighted and appear on the surface of the SOC film.

[0020] In recent years, therefore, a planarization method that applies imprint technology has been studied. In this method, a superstrate, which is a member on which no pattern is formed, is pressed against a liquid composition (curable material) supplied onto a wafer, and when the composition has spread, exposure is performed to harden the composition and separate the superstrate. The term "imprint" is often used to refer to the concept of transferring a pattern drawn on a mold by imprinting it, but in the planarization process, no pattern is drawn on the superstrate.

[0021] As shown in Fig. 1, the flattening apparatus 100 includes a substrate chuck 2, a substrate stage 3, a surface plate 4, a support 5, a top plate 6, a guide bar plate 7, a guide bar 8, a mold driving unit 9, a support 10, a mold chuck 12, a head 13, and an alignment shelf 14. The flattening apparatus 100 also includes a droplet supply unit 20, an off-axis alignment (OA) scope 21, a substrate transport unit 22, an alignment scope 23, a light source 24, a stage driving unit 31, a mold transport unit 32, a cleaning unit 33, and a control unit 40. The substrate chuck 2 and the substrate stage 3 constitute a substrate holding unit that holds the substrate 1, and the mold chuck 12 and the head 13 constitute a mold holding unit that holds the mold 11. Here, an XYZ coordinate system is defined such that the horizontal plane is the XY plane and the vertical direction is the Z-axis direction.

[0022] The substrate 1 is carried in from the outside of the planarization apparatus 100, for example, from a storage box in which the substrate is stored, by a substrate transport unit 22 including a transport hand and the like, and is held by the substrate chuck 2. The substrate stage 3 is supported by a base plate 4, and is driven in the X-axis direction and the Y-axis direction in order to position the substrate 1 held by the substrate chuck 2 at a predetermined position. The stage driving unit 31 includes, for example, a linear motor or an air cylinder, and drives (moves) the substrate stage 3 at least in the X-axis direction and the Y-axis direction, but may also have a function of driving the substrate stage 3 in two or more axial directions (for example, six axial directions). The stage driving unit 31 also includes a rotation mechanism, and drives (rotates) the chuck 2 or the substrate stage 3 to rotate around an axis parallel to the Z-axis direction.

[0023] The mold 11 is carried in from the outside of the flattening apparatus 100, for example, from a storage box in which the mold is stored, by a mold carrying unit 32 including a carrying hand and the like, and is held by the mold chuck 12. The mold 11 has, for example, a circular or rectangular outer shape, and includes a flat surface 11a on the lower surface. The flat surface 11a has a rigidity such that it contacts the curable material on the substrate and follows the surface shape of the substrate 1. The flat surface 11a has the same size as the substrate 1, or a size larger than the substrate 1. The mold chuck 12 is supported by the head 13, and has a function of correcting the rotation of the mold 11 around the Z axis, etc. Each of the mold chuck 12 and the head 13 includes an opening that passes light (ultraviolet light) irradiated from the light source 24 through a collimator lens. In addition, a load cell is arranged in the mold chuck 12 or the head 13 to measure the pressing force (impression force) of the mold 11 against the curable material on the substrate.

[0024] A support 5 that supports a top plate 6 is arranged on the surface plate 4. A guide bar 8 penetrates the top plate 6, with one end fixed to a guide bar plate 7 and the other end fixed to a head 13. The mold driving unit 9 is a mechanism that drives the head 13 in the Z-axis direction via the guide bar 8 to bring the mold 11 held by the mold chuck 12 into contact with the hardenable material on the substrate or to separate it from the hardenable material on the substrate. The mold driving unit 9 also has a function of driving (moving) the head 13 in the X-axis and Y-axis directions, and a function of rotating the mold chuck 12 or the head 13 around an axis parallel to the Z-axis direction.

[0025] The alignment shelf 14 is suspended from the top plate 6 via the support columns 10. A guide bar 8 passes through the alignment shelf 14. In addition, a height measurement system (not shown) is disposed on the alignment shelf 14 for measuring the height (flatness) of the substrate 1 held by the chuck 2, for example, by using an oblique incidence image shift method.

[0026] The OA scope 21 is supported by the alignment shelf 14. The OA scope 21 is used for an alignment process that detects alignment marks provided in a plurality of partial regions of the substrate 1 and determines the positions of each of the plurality of partial regions. The alignment scope 23 includes an optical system and an imaging system for observing a reference mark provided on the substrate stage 3 and an alignment mark provided on the mold 11. However, if an alignment mark is not provided on the mold 11, the alignment scope 23 may not be necessary. The alignment scope 23 is used for alignment that measures the relative positions of a reference mark provided on the substrate stage 3 and an alignment mark provided on the mold 11 and corrects the positional deviation. The positional relationship between the mold 11 and the substrate stage 3 is obtained by the alignment scope 23, and the positional relationship between the substrate stage 3 and the substrate 1 is obtained by the OA scope 21, whereby the relative alignment between the mold 11 and the substrate 1 can be performed.

[0027] The droplet supply unit 20 is composed of a dispenser including an outlet (nozzle) for discharging uncured (liquid) curable material onto the substrate 1, and drops and arranges (supplies) droplets of the curable material onto the substrate. The droplet supply unit 20 employs, for example, a piezo jet system or a micro solenoid system, and can supply droplets of the curable material onto the substrate in minute volumes. The number of outlets in the droplet supply unit 20 is not limited, and may be one (single nozzle) or more than 100. That is, a linear nozzle array may be used, or a combination of multiple linear nozzle arrays may be used.

[0028] The cleaning unit 33 cleans the mold 11 while the mold chuck 12 holds the mold 11. The cleaning unit 33 removes the mold 11, particularly the curable material adhering to the flat surface portion 11a, by separating the mold 11 from the cured curable material on the substrate. The cleaning unit 33 may, for example, wipe off the curable material adhering to the mold 11, or may remove the curable material adhering to the mold 11 by using UV irradiation, wet cleaning, plasma cleaning, or the like.

[0029] The control unit 40 includes a processing unit such as a CPU or other processor, an FPGA, and a storage unit such as a memory, and controls the entire planarization apparatus 100. The control unit 40 functions as a processing unit that performs planarization processing by comprehensively controlling each unit of the planarization apparatus 100.

[0030] Here, the flattening process refers to a process of flattening the hardenable material by bringing the flat portion 11a of the mold 11 into contact with the hardenable material on the substrate and making the flat portion 11a conform to the surface shape of the substrate 1. The flattening process is generally performed on a lot-by-lot basis, that is, for each of a plurality of substrates included in the same lot.

[0031] Next, an overview of the planarization process will be described with reference to Figures 2(a) to 2(c). In this embodiment, a process for planarizing the hardenable material IM by bringing the hardenable material IM on the entire surface of the substrate 1 into contact with the mold 11 will be described, but the hardenable material IM on a partial region of the substrate may also be planarized by bringing the hardenable material IM into contact with the mold.

[0032] First, as shown in FIG. 2(a), a plurality of droplets of the curable material IM are dropped from the droplet supply unit 20 onto the substrate 1 on which a base pattern is formed (supply step). FIG. 2(a) shows a state before the curable material IM is supplied onto the substrate and the mold 11 is brought into contact with the substrate. Next, as shown in FIG. 2(b), the curable material IM on the substrate is brought into contact with the flat surface portion 11a of the mold 11 to form a liquid film on the substrate (contact step). FIG. 2(b) shows a state in which the flat surface portion 11a of the mold 11 is entirely in contact with the curable material IM on the substrate, and the flat surface portion 11a of the mold 11 follows the surface shape of the substrate 1. Then, in the state shown in FIG. 2(b), the light source 24 irradiates the curable material IM on the substrate through the mold 11 with light to cure the curable material IM and form a cured film (curing step). Next, as shown in FIG. 2(c), the mold 11 is separated from the cured film on the substrate (separation step). This makes it possible to form a planarizing layer of the curable material IM with a uniform thickness over the entire surface of the substrate 1. Fig. 2(c) shows a state in which the planarizing layer of the curable material IM has been formed on the substrate.

[0033] When performing such a planarization process, problems such as defects may occur due to dry contact or seepage of the mold 11 and the substrate 1 caused by an excess or deficiency of the applied curable material IM. In this embodiment, in order to solve this problem, a taper is provided on the outer periphery of the flat part of the mold 11. That is, the mold 11 is formed with a tapered surface that connects the side end surface and the flat surface that forms the lower surface facing the substrate 1. The control unit 40 controls the amount of the curable material IM seeping out from between the flat part of the mold 11 and the substrate 1. Even if the curable material IM seeps out from between the flat surface of the mold 11 and the substrate 1, the film thickness of the curable material IM increases under the tapered surface, suppressing the amount of spread in the radial direction. This makes it possible to prevent the curable material IM from adhering to the end of the mold 11 and the end of the substrate 1.

[0034] However, depending on the density and unevenness of the device pattern, the desired flatness may not be obtained by one planarization. In such a case, the planarization process may be repeated several times on the same surface of the substrate to reduce the unevenness of the surface and improve the flatness. When the tapered mold 11 is used, a raised portion formed by the taper occurs on the outer periphery of the planarization film. This raised portion exists within an area where the accuracy is not required, which is acceptable in a general semiconductor process, and is removed in a later process, so it does not cause a problem. However, when the same substrate is planarized several times, the raised portion generated in the previous planarization may interfere with the mold 11 during the second or subsequent planarization. Since the raised portion generated in the previous planarization has already been hardened, the interference is also a dry contact similar to the contact between the mold 11 and the substrate 1 without the hardening material interposed therebetween, as described above. Such dry contact may cause particles or defects, or may affect the durability of the mold 11 or the substrate 1.

[0035] Therefore, in this embodiment, in the supplying step in the second planarization process after the first planarization process, the curable material is supplied so that the region of the cured film formed under the tapered surface in the first planarization process is covered by the liquid film formed in the contacting step in the second planarization process. In one example, the application range of the curable material IM in the next planarization process (second planarization process) is set to be larger than the previous one, relative to the spreading region of the curable material IM formed in the previous planarization process (first planarization process). That is, the supply range of the curable material in the supplying step in the second planarization process is set to be wider than the cured film formed in the first planarization process. As a result, the entire surface of the film formed in the previous planarization process is covered with the curable material IM, and dry contact can be prevented. Hereinafter, the planarization process in this embodiment will be described in detail with reference to FIG. 3, FIG. 4, and FIG. 5.

[0036] FIG. 3 is a flowchart showing an example of the flattening process in this embodiment.

[0037] In S1, the control unit 40 controls the mold transport unit 32 to transport the mold 11 into the apparatus and mount it on the mold chuck 12. As a result, the mold 11 is held by the mold chuck 12. In S2, the control unit controls the substrate transport unit 22 to transport the substrate 1 into the apparatus and mount it on the substrate chuck 2. As a result, the substrate 1 is held by the substrate chuck 2.

[0038] In S3, the control unit 40 performs measurement of the substrate 1 in order to determine the placement position of the curable material IM on the substrate 1. The measurement of the substrate 1 may include measurement of the boundary position or outer dimensions of the flat surface of the substrate 1, and measurement of the curved surface portion extending from the flat surface to the end surface. The measurement of the substrate 1 may further include measurement of at least one of an alignment mark or a characteristic pattern as the position of the device pattern provided on the substrate 1. By grasping the positional relationship between the shape of the substrate 1 and the pattern, the placement position of the curable material IM on the substrate can be determined. For example, as shown in FIG. 5(a), consider a state in which the center of the device pattern 210 expressed by a lattice pattern is eccentric with respect to the center of the outer shape of the substrate 1. In this case, when the curable material IM is dropped so as to cover only the device pattern 210 and contact control is performed so that the centers of the mold 11 and the substrate 1 are aligned, the curable material IM spreads eccentrically from the center of the mold 11 and the substrate 1. This can cause dry contact in areas with little curable material IM, and if a large amount of curable material IM is applied or if the application area is large, the curable material IM can seep out from between the mold 11 and the substrate 1 and adhere to the edges of the substrate 1 or the mold 11.

[0039] To prevent this, in S4, the control unit 40 determines a droplet arrangement pattern that does not cause dry contact and seepage based on the results of the measurement of the substrate 1 in S3. Specifically, the control unit 40 determines the droplet arrangement pattern so as to cover the device pattern 210 and the precision assurance range 200 shown by the dot pattern in Fig. 5(b), taking into account the amount of spread of the curable material IM due to contact with the mold 11.

[0040] In S5, the control unit 40 applies (supplies) the curable material IM on the substrate 1 according to the determined droplet arrangement pattern. Fig. 4(a) shows a state in which the curable material IM has been supplied on the substrate 1 in this manner.

[0041] The droplet arrangement pattern data for dropping the curable material IM on the substrate 1 may be created by the control unit 40 or an external computer (information processing device). When the external computer creates the droplet arrangement pattern data, the control unit 40 acquires the droplet arrangement pattern data from the external computer. In the following, the droplet arrangement pattern is created by the control unit 40. The control unit 40 creates a first droplet arrangement pattern data for dropping the curable material by the droplet supply unit 20 in the region D1 of the substrate 1 shown in FIG. 4(a). The first droplet arrangement pattern can be determined based on the density (roughness), pitch, width, etc. of the pattern of the region and the final thickness of the planarization layer when the curable material IM is planarized by the mold 11.

[0042] In S6, the control unit 40 aligns the centers of the substrate 1 and the mold 11, as shown in Fig. 5(c), and brings the mold 11 into contact with the curable material IM. Fig. 4(b) shows the state in which the mold 11 and the curable material IM are in contact. Fig. 5(c) shows an example in which the diameter of the mold 11 is larger than the diameter of the substrate 1, and therefore the end face 120 of the mold 11 is farther from the center than the end face of the substrate 1. However, the diameters of the two may be equal, or the relationship of size may be reversed.

[0043] When the mold 11 comes into contact with the curable material IM, the curable material IM spreads to a spread end 300, which is the end of the spread region represented by the hatched pattern in Fig. 5(d). At this time, the spread end 300 spreads outward beyond the taper start portion 110 of the mold 11. Also, as shown in Fig. 4(b), a spread region D2, which is the region of the spread curable material IM, is larger than the application range D1.

[0044] 6 shows the state in which the curable material IM has spread outward from the taper start portion 110 of the mold 11. By providing a taper on the outer periphery of the flat surface of the mold 11, the radial spread of the curable material IM that protrudes from between the flat surface of the mold 11 and the substrate 1 is converted into a direction in which the thickness increases from t1 to t2. This makes it easy to suppress the radial spread of the curable material IM, and prevents the curable material IM from adhering to the end face e1 of the substrate 1 and the end face e2 of the mold 11.

[0045] In S7, the control unit 40 uses the light source 24 to cure the curable material IM. Alternatively, if the curable material IM is a thermosetting material, heat is applied to cure the curable material IM. Thereafter, in S8, the control unit 40 controls the head 13 to perform demolding. Figure 4(c) shows the state after demolding.

[0046] As described above, when planarizing a substrate with a planarization device, the desired flatness may not be obtained in one planarization due to the density and unevenness of the device pattern. In such a case, the planarization process is performed multiple times to reduce the unevenness of the surface and improve the flatness. Therefore, in S9, the control unit 40 judges whether or not to repeat the planarization. The simplest example is to set the number of times N to repeat the planarization in advance. In this case, in S9, it is judged whether or not the current number of repetitions has reached N times. Alternatively, the flatness of the surface of the substrate 1 may be measured, and it may be judged whether or not the flatness obtained by the measurement is within an allowable range. If it is judged in S9 that the planarization is to be repeated, the process returns to S3. If it is judged in S9 that it is not necessary to repeat the planarization, the process ends.

[0047] In the following, a case where S3 and subsequent steps are performed again will be described. In S3, the control unit 40 performs measurement of the substrate 1 to determine the arrangement position of the curable material IM on the substrate 1. Next, in S4, the control unit 40 determines a droplet arrangement pattern based on the result of the measurement of the substrate 1 in S3, and in S5, applies (supplies) the curable material IM onto the substrate 1 according to the determined droplet arrangement pattern. Here, the application area on the substrate 1 is the area D3 as shown in FIG. 4(d), and the area D3 is assumed to be the same size as the previous application area D1. In this case, the area D3 is smaller than the spread area D2 shown in FIG. 4(c). Next, the control unit 40 aligns the substrate 1 and the mold 11 based on the measurement result of the substrate 1 in S3. However, due to factors such as measurement control error, the result does not completely match the result of the previous alignment of the substrate 1 and the mold 11, and an alignment error R may occur as shown in FIG. 4(e). In S6, the curable material IM comes into contact with the mold 11 in a state where an alignment error R occurs. Fig. 4(f) shows the state when the contact occurs. At this time, there is a possibility that the protruding portion t of the hardenable material IM in the outer peripheral tapered portion formed in the previous flattening process will come into dry contact with the mold 11. This means that the protruding portion t will interfere with the mold 11 before the hardenable material IM spreads in the radial direction due to the contact.

[0048] An example of this measure will be described with reference to Fig. 7. Fig. 7 is a diagram for explaining multiple flattening processes in this embodiment that do not cause dry contact. Here, Fig. 7(a) to (c) show the first flattening process, which is the same as Fig. 4(a) to (c).

[0049] After the initial planarization process S1 to S8 is performed and the operations shown in Fig. 7(a) to (c) are completed, a second planarization process is performed through S9. As the second planarization process, in S3, the control unit performs measurement of the substrate 1 to determine the arrangement position of the curable material IM on the substrate 1. This measurement of the substrate 1 may include measurement of the boundary position or outer dimensions of the flat surface of the substrate 1, and measurement of the curved surface portion extending from the flat surface to the end surface. Alternatively, the spread region D2 of the curable material IM formed by the previous planarization may be measured. In other words, the second planarization process may include a step of measuring the outer peripheral edge of the cured film formed by the first planarization process.

[0050] Next, in S4, the control unit 40 determines a droplet arrangement pattern based on the result of the measurement of the substrate 1 in S3. That is, the second planarization process may include a step of determining a supply range and a supply amount of the curable material in the supply step in the second planarization process based on the outer circumferential edge measured in S3. This step may be performed by an external computer or by the control unit 40. In addition, information on the spread region D2 of the curable material IM formed by the previous planarization may be obtained as a result of the measurement in S3 as described above, or may be obtained by other experiments or analyses.

[0051] Next, the control unit 40 performs alignment of the substrate 1 and the mold 11 based on the measurement result of the substrate in S3. In this alignment, the centers of the two may be aligned, or the centers of the spread region D2 of the curable material IM formed by the previous flattening and the mold 11 may be aligned.

[0052] In S5 of this embodiment, as shown in FIG. 7(d), the curable material IM is applied in a radial direction equal to or larger than the spread region D2 formed in the previous flattening process. That is, the curable material IM is applied so as to cover the raised portion. In another embodiment, the curable material IM may be applied inside the spread region D2 formed in the previous flattening process, as long as the curable material IM spreads at the time of contact so as to cover the raised portion. That is, the supply range of the curable material in the supply step in the second flattening process may be inside the outer circumferential edge of the cured film formed in the first flattening process. However, in that case, in the contact step in the second flattening process, the liquid film is spread so as to go over the outer circumferential edge of the cured film. In one example, the supply range of the curable material in the supply step in the second flattening process can be specified to be greater than −0.5 mm with respect to the outer circumferential edge of the cured film formed in the first flattening process. In this way, the curable material IM is applied so as not to make dry contact between the mold 11 and the raised portion.

[0053] FIG. 8(a) shows the spread end 300 of the hardenable material IM formed in the previous planarization process. FIG. 8(b) shows the state in which the hardenable material IM is applied to the application range 220 beyond the spread end 300 of the hardenable material IM formed in the previous planarization process. The state shown in FIG. 8(b) is a state in which the hardenable material IM covers the spread region D2 shown in FIG. 7(b) formed in the previous planarization process. In this case, as shown in FIG. 9(a), the raised portion t2 on the outer periphery of the spread region D2 formed by the tapered portion of the mold 11 in the previous planarization process is also covered by the hardenable material IM. Furthermore, depending on the application conditions and the application position accuracy, the hardenable material IM may be applied outside the spread region D2 formed in the previous planarization process. If the hardenable material IM is applied outside the spread region D2, the hardenable material IM may adhere to the end face e1 of the substrate 1, or may adhere outside the substrate 1. In addition, if the curable material IM is applied outside the spread region D2, the curable material IM that protrudes outside the spread region D2 may not be exposed to the curing light and may not be cured. Alternatively, if the curable material IM is a thermosetting material, if the curable material IM is applied outside the spread region D2, the heat that should be applied to the curable material IM that protrudes outside the spread region D2 may not reach the curable material IM that protrudes outside the spread region D2 and may not be cured. However, even if these phenomena occur, they may be acceptable if they do not lead to problems such as contamination of the equipment or materials.

[0054] Next, the control unit 40 aligns the substrate 1 and the mold 11 based on the measurement result of the substrate 1 in S3. However, due to factors such as measurement control error, the alignment result of the substrate 1 and the mold 11 will not completely match the alignment result of the substrate 1 and the mold 11 performed previously, and an alignment error R may occur as shown in FIG. 7(e). In S6, in a state in which an alignment error R occurs, the centers of the substrate 1 and the mold 11 are aligned, and the hardenable material IM and the mold 11 come into contact with each other. FIG. 7(f) shows the state at the time of contact. At this time, as shown in FIG. 9(b), the raised portion t2 of the hardenable material IM at the outer peripheral tapered portion formed by the previous flattening is covered by the hardenable material IM, so that dry contact between the substrate 1 and the raised portion t2 is prevented.

[0055] Next, the hardenable material IM spreads due to the contact of the mold 11, and spreads to the spread end 310, which is the end of the spread region represented by the hatched pattern in FIG. 8(d). At this time, the spread end 310 spreads outward from the taper start part 110 of the mold 11. Also, as shown in FIG. 7(g), the mold 11 is contacted in a positionally shifted state with respect to the substrate 1, resulting in a difference in the spread state between the left and right sides. In this case, on the left side of FIG. 7(g), as shown in FIG. 9(c), the radial spread of the hardenable material IM protruding from between the flat part of the mold 11 and the planarized film formed in the previous planarization process is converted to an increasing direction from film thickness t3 to film thickness t4. This makes it easy to suppress the radial spread of the hardenable material IM, and prevents the hardenable material IM from adhering to the end face e1 of the substrate 1 and the end face e2 of the mold 11. Also, on the right side of FIG. 7(g), as shown in FIG. 9(c), the radial spread of the curable material IM protruding from between the flat portion of the mold 11 and the planarized film formed in the previous planarization process is converted to a direction in which the thickness increases from t5 to t6. This makes it easy to suppress the radial spread of the curable material IM, and prevents the curable material IM from adhering to the end face e1 of the substrate 1 and the end face e2 of the mold 11. To obtain such an effect, as an example, it is preferable that the tapered surface has a taper angle of 0.1 to 20 degrees with respect to the flat surface. Also, the area of ​​the tapered surface can be 1 / 15 or less of the area of ​​the flat surface. Also, it is preferable that the length of the tapered surface in the radial direction of the superstrate is at least 0.2 mm.

[0056] Depending on the amount of the curable material IM applied, the thickness of the curable material IM that protrudes due to contact may not necessarily increase. Also, the curable material IM that does not come into contact with the mold 11 in the contact step is cured as is, but this is not a problem as long as it does not affect the quality or process.

[0057] According to the embodiment described above, it is possible to prevent dry contact even when the planarization process is performed multiple times. It is also possible to prevent the hardening material IM from seeping out from between the mold 11 and the substrate 1 and adhering to the edge of the substrate or the mold due to factors such as a large amount of hardening material IM applied or a large application area.

[0058] <Embodiment of the article manufacturing method> Next, a method for manufacturing an article (such as a semiconductor IC element, a liquid crystal display element, a color filter, or a MEMS) using the above-mentioned planarization device will be described. The manufacturing method includes a step of planarizing a composition disposed on a substrate (such as a wafer or a glass substrate) using a film-forming device as the above-mentioned planarization device, and a step of curing the composition. This results in a planarization film being formed on the substrate. Then, the substrate on which the planarization film has been formed is subjected to a process such as forming a pattern using a lithography device, and the processed substrate is processed in other well-known processing steps to manufacture an article. The other well-known steps include patterning exposure and the associated pre-processing, etching, resist peeling, dicing, bonding, packaging, and the like. This manufacturing method makes it possible to manufacture an article of higher quality than before.

[0059] The disclosure of the present specification includes at least the following technical ideas. (Item 1) a step of providing a curable material on a substrate; a contacting step of contacting a superstrate with the curable material dispensed on the substrate to form a liquid film on the substrate; a forming step of hardening the liquid film to form a hardened film; separating the superstrate from the cured film; A planarization method for repeatedly performing a planarization process including the steps of: The superstrate has a tapered surface connecting a side end surface and a flat surface forming a lower surface facing the substrate, In the supplying step in the second planarization process after the first planarization process, the curable material is supplied so that the region of the cured film formed under the tapered surface in the first planarization process is covered by the liquid film formed in the contacting step in the second planarization process. A planarization method comprising: (Item 2) 2. The planarization method according to item 1, wherein a supply range of the curable material in the supply step in the second planarization treatment is wider than the cured film formed in the first planarization treatment. (Item 3) The planarization method according to item 1, characterized in that the supply range of the curable material in the supply step in the second planarization process is inside the outer peripheral edge of the cured film formed in the first planarization process, but in the contact step in the second planarization process, the liquid film spreads so as to go over the outer peripheral edge of the cured film. (Item 4) 2. The planarization method according to item 1, wherein a supply range of the curable material in the supply step in the second planarization treatment is greater than −0.5 mm from an outer peripheral edge of the cured film formed in the first planarization treatment. (Item 5) The second planarization process includes: measuring an outer circumferential edge of the cured film formed in the first planarization treatment; determining a supply range and a supply amount of the curable material in the supply step of the second flattening treatment based on the measured outer circumferential edge; 5. The planarization method according to any one of items 1 to 4, comprising: (Item 6) 6. The planarization method according to any one of items 1 to 5, wherein the planarization process further comprises a step of aligning the substrate and the superstrate before or during the contacting step. (Item 7) 7. The flattening method according to any one of items 1 to 6, wherein the diameter of the superstrate is 200 to 400 mm. (Item 8) 8. The planarization method according to item 7, wherein the tapered surface has a taper angle of 0.1 to 20 degrees with respect to the flat surface. (Item 9) 9. The planarization method according to item 8, wherein an area of ​​the tapered surface is 1 / 15 or less of an area of ​​the flat surface. (Item 10) 10. The planarization method of item 9, wherein the length of the tapered surface in the radial direction of the superstrate is at least 0.2 mm. (Item 11) Forming a film of a curable material on a substrate according to the planarization method of any one of items 1 to 10; a step of processing the substrate on which the film is formed in the step; and manufacturing an article from the processed substrate.

[0060] The invention is not limited to the above-described embodiments, and various modifications and variations are possible without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0061] 2: substrate chuck, 3: substrate stage, 9: mold drive unit, 12: mold chuck, 13: head, 20: droplet supply unit, 22: substrate transport unit, 24: light source, 31: stage drive unit, 40: control unit, 100: flattening device

Claims

1. a step of providing a curable material on a substrate; a contacting step of contacting a superstrate with the curable material dispensed on the substrate to form a liquid film on the substrate; a forming step of hardening the liquid film to form a hardened film; separating the superstrate from the cured film; A planarization method for repeatedly performing a planarization process including the steps of: The superstrate has a tapered surface connecting a side end surface and a flat surface forming a lower surface facing the substrate, In the supplying step in the second planarization process after the first planarization process, the curable material is supplied so that the region of the cured film formed under the tapered surface in the first planarization process is covered with the liquid film formed in the contacting step in the second planarization process. A planarization method comprising:

2. 2. The planarization method according to claim 1, wherein a supply range of the curable material in the supplying step in the second planarization treatment is wider than the cured film formed in the first planarization treatment.

3. The planarization method of claim 1, characterized in that the supply range of the curable material in the supply process in the second planarization process is inside the outer peripheral edge of the cured film formed in the first planarization process, but in the contact process in the second planarization process, the liquid film spreads so as to overcome the outer peripheral edge of the cured film.

4. 2. The planarization method according to claim 1, wherein a supply range of the curable material in the supply step in the second planarization treatment is greater than −0.5 mm from an outer peripheral edge of the cured film formed in the first planarization treatment.

5. The second planarization process includes: measuring an outer circumferential edge of the cured film formed in the first planarization treatment; determining a supply range and a supply amount of the curable material in the supply step of the second flattening process based on the measured outer circumferential edge; The method of claim 1 , further comprising:

6. 2. The method of claim 1, wherein the planarization process further comprises aligning the substrate and the superstrate before or during the contacting step.

7. 2. The method of claim 1, wherein the diameter of the superstrate is 200-400 mm.

8. 8. The planarization method according to claim 7, wherein the tapered surface has a taper angle of 0.1 to 20 degrees with respect to the flat surface.

9. 9. The planarization method according to claim 8, wherein an area of ​​the tapered surface is 1 / 15 or less of an area of ​​the flat surface.

10. 10. The method of claim 9, wherein the length of the tapered surface in a radial direction of the superstrate is at least 0.2 mm.

11. forming a film of a curable material on a substrate according to the planarization method of any one of claims 1 to 10; a step of processing the substrate on which the film is formed in the step; and manufacturing an article from the processed substrate.

Images