Patent Application
20190285982
The present invention relates to a mold used for an imprint process, an imprint apparatus for forming a pattern on an imprint material onto a substrate using a mold, and a method of manufacturing an article.
An imprint apparatus for forming a pattern on an imprint material onto a substrate by using a mold on which a concave-convex pattern is formed has attracted attention as one type of mass-production lithography apparatus for semiconductor devices and the like. The imprint apparatus can form a pattern on an imprint material onto a substrate by curing the imprint material while the imprint material on the substrate is in contact with a mold and separating the mold from the cured imprint material. The process of forming a pattern on an imprint material onto a substrate by using a mold in this manner is generally called an imprint process.
In the imprint apparatus, in a contact process of bringing an imprint material on a substrate into contact with a mold, a pattern concave portion of the mold may not be fully filled with the imprint material to leave air bubbles between the mold and the imprint material. In this case, a pattern transfer failure (defect) onto the substrate can occur in a portion in which air bubbles are left. For this reason, in a contact process, the space between the mold and the substrate is preferably filled with a gas (to be sometimes referred to as a “filling promotion gas” hereinafter) for promoting the filling of the concave-convex pattern of the mold with the imprint material.
Japanese Patent No. 5828626 has proposed a technique of supplying a filling promotion gas to a moving path for the movement of a substrate from below a dispenser for dispensing an imprint material onto a substrate to below the mold. This moves a filling promotion gas to below the mold together with the substrate and makes the filling promotion gas efficiently flow into a narrow space between the mold and the substrate. Japanese Patent No. 5745532 has proposed a technique of forming a through hole in a mold and supplying a filling promotion gas into the space between the mold and a substrate via the through hole.
Some imprint apparatus uses a method of improving throughput by supplying an imprint material to each of a plurality of shot regions on a substrate and then performing an imprint process for each of the plurality of shot regions to which the imprint material has been supplied. In such a method, as disclosed in Japanese Patent No. 5828626, no filling promotion gas can be supplied to a moving path at the time of movement of a substrate from below a dispenser to below a mold, and it can be difficult to efficiently supply a filling promotion gas to the space between the mold and the substrate. In addition, in providing a through hole in a mold as disclosed in Japanese Patent No. 5745532, it is difficult to clean the through hole as well as performing a polishing process inside the through hole. As a consequence, foreign substances (particle) can be easily generated from the through hole.
The present invention provides a technique advantageous in reducing transfer failures of patterns onto substrates.
According to one aspect of the present invention, there is provided a mold having a concave-convex pattern, the pattern being transferred onto an imprint material on a substrate by an imprint apparatus, the mold comprising: a first surface having a pattern portion on which the pattern; and a second surface located on an opposite side to the first surface, wherein a concave portion that does not penetrate to the second surface is provided in the first surface so as to be spaced apart from the pattern portion.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Exemplary embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the same reference numerals denote the same members throughout the drawings, and a repetitive description thereof will not be given. Assume that in the following description, two different (orthogonal) directions in a plane parallel to a surface of a substrate are defined as an X direction and a Y direction, respectively, and a direction perpendicular to the surface of the substrate is defined as a Z direction.
<First Embodiment>
An imprint apparatus 100 according to the first embodiment of the present invention will be described. The imprint apparatus is an apparatus for forming a pattern of a curable material onto which a concave-convex pattern on a mold is transferred by bringing an imprint material supplied onto a substrate into contact with the mold and applying energy for curing the imprint material. The imprint apparatus 100 is used to manufacture a semiconductor device and the like and performs an imprint process of transferring a concave-convex pattern onto an imprint material R supplied onto a shot region of a substrate W by using a mold M, on which the pattern is formed. For example, the imprint apparatus 100 cures the imprint material R while the mold M on which the pattern is formed is in contact with the imprint material R on the substrate. The imprint apparatus 100 can then form a pattern on the imprint material R by increasing the spacing between the mold M and the substrate W and separating (releasing) the mold M from the cured imprint material R.
Methods of curing an imprint material include a thermal cycle method using heat and a photo-curing method using light. This embodiment will exemplify a case using the photo-curing method. The photo-curing method is a method of curing an imprint material by supplying an uncured ultraviolet curable resin as the imprint material onto a substrate and irradiating the imprint material with light (ultraviolet light) while a mold 1 is in contact with the imprint material.
As the imprint material, a curable composition (to be also referred to as a resin in an uncured state) to be cured by energy for curing is used. As the energy for curing, an electromagnetic wave, heat, or the like is used. The electromagnetic wave is, for example, light such as infrared rays, visible light, or UV rays whose wavelength is selected from the range of 10 nm to 1 mm.
The curable composition is a composition cured by light irradiation or heating. A photo-curable composition cured by light contains at least a polymerizable compound and a photopolymerization initiator, and may contain a nonpolymerizable compound or a solvent as needed. The nonpolymerizable compound is at least one material selected from the group consisting of a sensitizer, a hydrogen donor, an internal mold release agent, a surfactant, an antioxidant, and a polymer component.
The imprint material is applied in a film shape onto the substrate by a spin coater or a slit coater. Alternatively, the imprint material may be applied, onto the substrate, in a droplet shape or in an island or film shape formed by connecting a plurality of droplets using a liquid injection head. The viscosity (viscosity at 25° C.) of the imprint material is, for example, 1 mPa.s to 100 mPa.s.
[Apparatus Arrangement]
The arrangement of the imprint apparatus 100 according to the first embodiment will be described next with reference to
The substrate stage 11 includes, for example, a substrate holding unit 11a and a substrate driving unit 11b, and is configured to be movable while holding the substrate W. The substrate holding unit 11a holds the substrate W with, for example, a vacuum suction force or electrostatic force. The substrate driving unit 11b mechanically holds the substrate holding unit 11a and drives the substrate holding unit 11a (substrate W) in the X and Y directions. In addition, the substrate driving unit 11b may be configured to change the position of the substrate W in the Z direction, the tilt of the substrate W relative to the X-Y plane, and the rotation of the X-Y plane.
In this case, glass, ceramic, a metal, a semiconductor, a resin, or the like may be used for the substrate W, and a member made of a material different from that of the substrate may be formed on its surface, as needed. Specific examples of the substrate W include a silicon wafer, compound semiconductor wafer, and quartz glass. An adhesive layer may be provided before the addition of an imprint material to improve the adhesiveness between the imprint material and the substrate, as needed.
The imprint head 12 can include a mold holding unit 12a that holds the mold M with, for example, a vacuum suction force or electrostatic force and a mold driving unit 12b configured to change the position and tilt of the mold holding unit 12a (mold 1) in the Z direction. In addition, the mold driving unit 12b may be configured to adjust the positions of the mold M in the X and Y directions.
The arrangement of the mold M held by the imprint head 12 will be described below.
The first surface 31 is provided with a pattern portion 31a having a concave-convex pattern to be transferred as a device pattern onto an imprint material on a substrate. The pattern portion 31a is formed from, for example, a stepped portion (that is, a mesa shape) with a size of above several 10 μm, which protrudes from the first surface 31 toward the substrate. Although the size of the pattern portion 31a differs depending on a device pattern to be transferred onto a substrate, the size is generally set to 33 mm×26 mm.
The second surface 32 includes a held portion 32a that comes into contact with the holding surface of the mold holding unit 12a and is held by the mold holding unit 12a and a cavity 32b (second concave portion) provided on the opposite side to the pattern portion 31a of the first surface 31 and its surroundings. The cavity 32b is provided to easily deform the first surface 31 into a convex shape such that the central portion of the pattern portion 31a protrudes toward the substrate W when, for example, the mold M comes into contact with the imprint material R on the substrate. The cavity 32b becomes an almost sealed space when being held by the mold holding unit 12a, and communicates with the deformation unit 13 (to be described later) via a pipe 13a.
The deformation unit 13 adjusts the internal pressure of the cavity 32b by controlling the supply of compressed air into the cavity 32b of the mold M held by the imprint head 12, and deforms the first surface 31 of the mold M into a convex shape. The deformation unit 13 can reduce air bubbles left between the mold M and the imprint material R by controlling the deformation of the first surface 31 so as to gradually increase the contact area between the mold M and the imprint material R on the substrate in a process of bringing the mold M into contact with the imprint material R.
The curing unit 14 irradiates a substrate W with light (for example, ultraviolet light) for curing the imprint material R via the mold M in a process of curing the imprint material R on the substrate. In this embodiment, light emitted from the curing unit 14 is reflected by a beam splitter 19 (for example, a dichroic mirror) and irradiates the substrate W via a relay optical system 20 and the mold M. The dispenser 15 dispenses (applies) the imprint material R onto the substrate. As described above, the imprint apparatus 100 according to this embodiment can dispense an ultraviolet curable resin having a property of being cured by irradiation with ultraviolet light as the imprint material R from the dispenser 15 onto the substrate.
The image capturing unit 16 captures an image of the pattern portion 31a of the mold M via the beam splitter 19 and the relay optical system 20. For example, the image capturing unit 16 captures an image of the pattern portion 31a at each of a plurality of timings while the contact area between the mold M and the imprint material R is increased. Each image obtained by the image capturing unit 16 in this manner has interference fringes caused by contact between the mold M and the substrate W, and hence it is possible to observe, based on each image, the manner of how the contact area between the pattern portion 31a and the imprint material R increases. In addition, the imprint apparatus 100 may be provided with, for example, a detector (alignment scope) that detects alignment marks on the mold M and the substrate W to align the mold M and the substrate W
The supply unit 17 supplies a gas (filling promotion gas) for promoting the filling of the concave-convex pattern of the mold M with the imprint material R to between the mold M and the substrate W. The supply unit 17 has a blowing-out port 17a (supply port or nozzle) for blowing out a filling promotion gas from a side of the mold M to between the mold M and the substrate W, and supplies a filling promotion gas via the blowing-out port 17a. The blowing-out port 17a can be arranged near, for example, the mold M held by the imprint head 12. In the case shown in
In this case, examples of a filling promotion gas that can be used include a gas having a small molecular weight and high permeability with respect to the mold M, such as helium gas, and a condensable gas that liquefies when the mold M comes into contact with the imprint material R on the substrate, such as PFP (pentafluoropropane) gas. As shown in
[Imprint Process]
An imprint process performed by the imprint apparatus 100 according to this embodiment will be described next. The imprint apparatus 100 according to the embodiment can be configured to sequentially dispense the imprint material R from the dispenser 15 to each of a plurality of shot regions on the substrate W and then sequentially perform an imprint process for each of the plurality of shot regions.
In step S11, as shown in
In step S15, the control unit 18 drives the substrate stage 11 to arrange a shot region subjected to an imprint process (to be referred to as a target region hereinafter) of a plurality of shot regions on the substrate W to below the pattern portion 31a of the mold M. In step S16, the control unit 18 controls the deformation unit 13 to deform the mold M (first surface 31 and pattern portion 31a) into a convex shape. In step S17, as shown in
In step S18, the control unit 18 controls the supply unit 17 to stop supplying the filling promotion gas, and leaves the mold M and the imprint material R in a contact state for a predetermined time. The predetermined time is the time (filling time) for filling the concave-convex pattern (concave portions) of the pattern portion 31a with the imprint material R, and can be set in advance. In step S19, the control unit 18 controls the curing unit 14 to irradiate the imprint material R with light while the mold M is in contact with the imprint material R, thereby curing the imprint material R (curing step). In step S20, the control unit 18 controls the imprint head 12 to increase the spacing between the mold M and the substrate W, and separates the cured imprint material R from the mold M (releasing step), as shown in
In step S21, the control unit 18 determines whether an imprint process has been performed for all the plurality of shot regions on the substrate W. If there is no shot region (unprocessed shot region) for which an imprint process has not been performed, the processing is terminated. In contrast, if there is any unprocessed shot region, the process advances to step S22. In step S22, the control unit 18 controls the supply unit 17 to supply a filling promotion gas to between the mold M and the substrate W. The process then returns to step S15 to set the unprocessed shot region as a target shot region and perform an imprint process, as shown in
In this case, in the flowchart shown in
[Arrangement of Mold]
As described above, the imprint apparatus 100 according to this embodiment is configured to continuously dispense the imprint material R onto each of a plurality of shot regions on the substrate W and then continuously perform an imprint process for each of the plurality of shot regions. Such a method is advantageous in improving throughput. However, because a filling promotion gas is supplied while the substrate W is arranged below the mold M, it can be difficult to efficiently make the filling promotion gas flow into the narrow space S between the pattern portion 31a of the mold M and the substrate W. In addition, when the mold M is brought into contact with the imprint material R, the spacing between the mold M and the substrate W decreases, and the filling promotion gas leaks from between the mold M and the substrate W. For this reason, as an imprint process is repeated, the concentration of the filling promotion gas in the space S can decrease at the time of an imprint process.
The mold M according to this embodiment has a concave portion 31b provided in a peripheral portion (surrounding portion) of the pattern portion 31a on the first surface 31 so as not to penetrate to second surface 32. As described above, providing the concave portion 31b in the first surface 31 makes it possible to make a filling promotion gas existing in the space S between the pattern portion 31a and the substrate W flow into the concave portion 31b and temporarily retain the gas when the mold M comes into contact with the imprint material R. In addition, when the spacing between the mold M and the substrate W is increased to separate the mold M from the cured imprint material R, the filling promotion gas in the concave portion 31b can be made to flow into the space S. Using the mold M having the concave portion 31b provided in the first surface 31 in this manner can reduce a reduction in the concentration of the filling promotion gas in the space S at the time of an imprint process.
In this case, the volume of the concave portion 31b provided in the first surface 31 of the mold M is preferably larger than the maximum volume of the space S formed between the pattern portion 31a and the substrate W in an imprint process. Configuring the mold M in this manner can make all the filling promotion gas in the space S flow into the concave portion 31b. This can further efficiently reduce a reduction in the concentration of the filling promotion gas.
An example of the arrangement of the mold M having the concave portion 31b provided in the first surface 31 will be described below with reference to
The mold M shown in
The mold M shown in
As described above, the mold M according to this embodiment has the concave portion 31b provided in a portion of the first surface 31 which is located around the pattern portion 31a. Performing an imprint process by using the mold M having the concave portion 31b provided in the first surface 31 in this manner makes it possible to temporarily retain, in the concave portion 31b, the filling promotion gas in the space S between the pattern portion 31a of the mold M and the substrate W at the time of a contact step. Even if, therefore, an imprint process is to be continuously performed for a plurality of shot regions on the substrate W, it is possible to reduce a reduction in the concentration of the filling promotion gas in the space S.
<Second Embodiment>
The second embodiment according to the present invention will be described. In a method of continuously dispensing an imprint material R for each of a plurality of shot regions on a substrate W, blowing out a filling promotion gas from a blowing-out port 17a can cause volatilization, shape change, positional shift, and the like of the imprint material R on other shot regions. A mold M is preferably configured such that a filling promotion gas blown out from the blowing-out port 17a can efficiently flow between a mold M and the substrate W. The mold M according to the second embodiment has a flow channel 31c provided in a first surface 31 so as to make a concave portion 31b of the first surface 31 communicate with a side surface 33 of the mold M.
The flow channel 31c is, for example, a groove provided in the first surface 31 so as to connect the concave portion 31b of the first surface 31 to the side surface 33 of the mold M. The flow channel 31c is provided in the first surface 31 to facilitate supplying the gas blown out from the blowing-out port 17a into the concave portion 31b via the flow channel 31c when a mold holding unit 12a holds the mold M. That is, the flow channel 31c can be provided at a position of the side surface 33 of the mold M which faces the blowing-out port 17a. In the mold M configured in this manner, the blowing-out port 17a may be configured to blow out a filling promotion gas toward the side surface 33 of the mold M instead of being configured to blow out a filling promotion gas to between the mold M and the substrate W. In this case, the number of flow channels 31c is not limited to one, and flow channels 31c may be provided in two or more side surfaces 33 of the mold M.
As described above, the mold M according to this embodiment is provided with the flow channel 31c to make the concave portion 31b of the first surface 31 communicate with the side surface 33 of the mold M. This makes it possible to reduce a reduction in the concentration of a filling promotion gas at the time of an imprint process and efficiently supply the filling promotion gas to the concave portion 31b of the first surface 31 as in the first embodiment. In addition, when a plurality of blowing-out ports 17a are provided, blowing out a filling promotion gas from only the blowing-out port 17a, of the blowing-out ports 17a, which faces the flow channel 31c can reduce the influence on the imprint material R on other shot regions.
<Third Embodiment>
The third embodiment of the present invention will be described. When a target shot region subjected to an imprint process is located on a peripheral edge portion of a substrate W, a mold M sometimes partly protrudes from the substrate W in the X and Y directions.
As shown in
<Embodiment of Method of Manufacturing Article>
A method of manufacturing an article according to an embodiment of the present invention is suitable for manufacturing an article, for example, a microdevice such as a semiconductor device or an element having a microstructure. The method of manufacturing the article according to this embodiment includes a step of forming a pattern on an imprint material supplied (dispensed) onto a substrate using the above-described imprint apparatus (imprint method), and a step of processing the substrate on which the pattern is formed in the preceding step. This manufacturing method further includes other known steps (oxidation, deposition, vapor deposition, doping, planarization, etching, resist separation, dicing, bonding, packaging, and the like). The method of manufacturing the article according to this embodiment is advantageous in at least one of the performance, the quality, the productivity, and the production cost of the article, as compared to a conventional method.
The pattern of a cured product formed using the imprint apparatus is used permanently for at least some of various kinds of articles or temporarily when manufacturing various kinds of articles. The articles are an electric circuit element, an optical element, a MEMS, a recording element, a sensor, a mold, and the like. Examples of the electric circuit element are volatile and nonvolatile semiconductor memories such as a DRAM, a SRAM, a flash memory, and a MRAM and semiconductor elements such as an LSI, a CCD, an image sensor, and an FPGA. Examples of the mold are molds for imprint.
The pattern of the cured product is directly used as the constituent member of at least some of the above-described articles or used temporarily as a resist mask. After etching or ion implantation is performed in the substrate processing step, the resist mask is removed.
A detailed method of manufacturing an article will be described next. As shown in
As shown in
As shown in
As shown in
<Other Embodiments>
Embodiment(s) of the present invention can also be realized by a computer of a system or apparatus that reads out and executes computer executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be referred to more fully as a ‘non-transitory computer-readable storage medium’) to perform the functions of one or more of the above-described embodiment(s) and/or that includes one or more circuits (e.g., application specific integrated circuit (ASIC)) for performing the functions of one or more of the above-described embodiment(s), and by a method performed by the computer of the system or apparatus by, for example, reading out and executing the computer executable instructions from the storage medium to perform the functions of one or more of the above-described embodiment(s) and/or controlling the one or more circuits to perform the functions of one or more of the above-described embodiment(s). The computer may comprise one or more processors (e.g., central processing unit (CPU), micro processing unit (MPU)) and may include a network of separate computers or separate processors to read out and execute the computer executable instructions. The computer executable instructions may be provided to the computer, for example, from a network or the storage medium. The storage medium may include, for example, one or more of a hard disk, a random-access memory (RAM), a read only memory (ROM), a storage of distributed computing systems, an optical disk (such as a compact disc (CD), digital versatile disc (DVD), or Blu-ray Disc (BD)™), a flash memory device, a memory card, and the like.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims the benefit of Japanese Patent Application No. 2018-045925 filed on Mar. 13, 2018, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2018-045925 | Mar 2018 | JP | national |
