Patent Application
20200307038
The present disclosure relates to a molding method, a molding apparatus, an imprint method, a method for manufacturing an article, and an article manufacturing system.
As a technique for molding a curable composition on a substrate, an imprint technique is known. A light curing method is one of imprint techniques. In the imprint method based on the light curing method, first, an uncured imprint material (occasionally referred to as “photo-curable composition” or “photo-curable resin”) is supplied onto a substrate (e.g., a wafer). Next, imprint material on the substrate and a mold are brought into contact with each other (a pressing step). Then, light (ultraviolet light) is emitted to the imprint material in the state where the imprint material and the mold are in contact with each other (a curing step), thereby curing the imprint material. After the imprint material is cured, the distance between the substrate and the mold is widened (a releasing step). Accordingly, the mold is pulled away from the cured imprint material, and a resin pattern is formed on the substrate.
In the state where the imprint material and the mold are in contact with each other, an imprint apparatus needs to adjust the position of a pattern formed in advance on the substrate (a substrate side pattern) with the position of a pattern formed in the mold (a mold pattern portion). In the position adjustment between the substrate and the mold, the substrate and the mold are moved relative to each other, whereby a force acts in a direction opposite to the relative moving direction of the substrate and the mold due to viscoelasticity of the imprint material. This force is referred to as a “shearing force”. In the position adjustment between the substrate and the mold, the shearing force may cause distortion in a plane between the substrate and the mold. The distortion in the plane between the substrate and the mold caused by the shearing force decreases the accuracy of the position adjustment between the substrate and the mold.
Japanese Patent Application Laid-Open No. 2015-29073 discusses a method for causing condensable gas to permeate an imprint material, thereby increasing the film thickness of the imprint material, reducing the shearing force of the imprint material, and improving the accuracy of position adjustment.
Meanwhile, Japanese Patent Application Laid-Open No. 2016-58735 discusses a method for emitting light to an imprint material simultaneously with or before the position adjustment between a substrate and a mold. A purpose of the method is to prevent the deterioration of the positional accuracy caused by a disturbance such as the vibration of an apparatus due to low viscoelasticity. The method increases the shearing force of the imprint material, and thereby improving the accuracy of the position adjustment.
In a case where imprint is performed in each of different areas on the substrate, the result of the imprint differs from area to area due to the occurrence of distortion or a defect only in a particular area, depending on the application state of a base layer or the state of the surface of the substrate to which the base layer is applied.
For example, in a case where the thickness of the base layer is distributed in the plane of the substrate, the distribution of the shearing force may occur in the plane of the substrate, or influence on imprint may differ if particles are stuck.
However, Japanese Patent Application Laid-Open No. 2015-29073 and 2016-58735 do not discuss a method considering an influence on imprint in different areas on a base layer.
If imprint is performed in each area in the state where the shearing force is distributed in the plane, distortion occurs in some of the areas when the position adjustment between the substrate and the mold is made. This decreases the accuracy of the position adjustment.
The present disclosure is directed to providing a molding method for achieving suitable imprint over the entire surface of a substrate.
According to an aspect of the present disclosure, a molding method for placing a curable composition on a substrate including a base layer on a surface of the substrate and obtaining a cured product molded on the substrate using a mold includes making position adjustment between the mold and the substrate in a state where the mold and the base layer of the substrate are in contact with the curable composition, measuring an in-plane distribution of a shearing force generated when the position adjustment is made, or an in-plane distribution of a film thickness of the base layer, and determining an application condition of the base layer or a detection condition for alignment detection through the base layer based on a result of at least one of the in-plane distribution of the shearing force and the in-plane distribution of the film thickness of the measuring step.
Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Desirable exemplary embodiments of the present disclosure will be described in detail below based on the attached drawings.
In the following exemplary embodiments, a detailed description is given of an imprint method and an imprint apparatus for placing on a substrate an imprint material that is a curable composition and forming a pattern of a cured product on the substrate using a mold having an uneven pattern (e.g., concave-convex pattern) on its surface. The present disclosure, however, is not limited to this, and is also applicable to, for example, a molding method and a molding apparatus for a planarization apparatus for forming a flat surface on a substrate using a flat mold.
The control unit 14 may be built into either of the apparatuses, or may be an external control unit. A configuration may be employed in which the application apparatus 13, the imprint apparatus 12, and the control unit 14 are connected to each other via the Internet.
In step S1, before the imprint apparatus 12 performs imprint, a method for manufacturing an article according to the present exemplary embodiment applies a base layer 1 to a place on a substrate 9 onto which a pattern is to be transferred, using the application apparatus 13 as the preprocessing apparatus.
As the application apparatus 13, an application apparatus termed a coater/developer is used as an example. For applying the base layer 1, a spin coating process and a baking process are used. As the material of the base layer 1, for example, spin-on carbon (SOC) is used. As illustrated in
The substrate 9 on which the base layer 1 has been applied by the application apparatus 13 is conveyed to the imprint apparatus 12 illustrated in
In the present exemplary embodiment, a photo-curable composition is used as the imprint material 8.
An imprint head (not illustrated) holds the mold 6 with a vacuum suction force or an electrostatic force. The imprint head is configured to drive the mold 6 in the Z-axis direction. In step S2, when bringing the pattern portion 7 and the imprint material 8 into contact with each other, the imprint head lowers and presses the mold 6 in the −Z-direction.
In step S3, the shearing force of the imprint material 8 is measured, in the state where the mold 6 is lowered and pressed in the −Z-direction.
A wafer stage 4 illustrated in
While the wafer stage 4 moves in the horizontal direction, the distance between the surface of the substrate 9 and the mold 6 is maintained at 1 mm or less. With such a narrow gap, it is possible to quickly perform the operation of bringing the mold 6 and the imprint material 8 into contact with each other and the operation of pulling the mold 6 and the imprint material 8 away from each other in the imprint process.
In the state where the mold 6 is pressed (i.e., the state where the imprint material 8 is in contact with the substrate 9 and the mold 6), the substrate 9 and the mold 6 are moved relative to each other in the X-direction or the Y-direction, whereby a force acts in a direction opposite to the relative moving direction of the substrate 9 and the mold 6 due to the viscoelasticity of the imprint material 8. This force is referred to as a “shearing force”.
When the mold 6 is fixed, and the wafer stage 4 is positioned in the XY-plane, the driving force of the wafer stage 4 increases to balance the shearing force generated in the direction opposite to the relative moving direction.
In step S3, the driving force of the wafer stage 4 is detected, thereby measuring the shearing force generated in the imprint material 8 when the mold 6 and the wafer stage 4 move relative to each other.
The measured value of the shearing force is obtained in each of a plurality of imprint shot areas on the substrate 9. Consequently, it becomes possible to obtain the in-plane distribution of the shearing force on the substrate 9, i.e., the base layer 1.
In step S4, the measurement result of the shearing force measured in step S3 is fed back to the preprocessing apparatus (not illustrated). Based on information regarding the fed back shearing force, the control unit 14 determines the application condition of the base layer 1 (an application condition determination step), and changes the application condition in the application apparatus 13.
The present inventors have focused on the issue that a difference occurs in the distribution of the shearing force on the surface of the substrate 9, whereby distortion or a positional shift occurs in a cured pattern to be formed.
After diligent consideration of this issue, the present inventors have newly found out that the shearing force acting on the imprint material 8 when position adjustment is made depends on the state of the base layer 1, specifically, the film thickness of the base layer 1. The present disclosure has been made based on this.
That is, the present disclosure is based on new knowledge that if the film thickness of the base layer 1 applied to the same substrate or a plurality of substrates created under the same condition is made larger, the shearing force acting on the imprint material 8 when position adjustment is made can be made smaller.
To reduce the difference in the in-plane distribution of the shearing force, steps S1 to S4 are repeated until the shearing force in each imprint shot area in the plane falls within an acceptable range. Alternatively, after steps S1 to S4 are repeated as many times as determined in advance, the processing may proceed to step S5.
If the shearing force in one or more imprint shots falls within the acceptable range in a certain substrate 9, the application condition of the preprocessing apparatus (not illustrated) may be fixed, and another substrate 9 may be imprinted.
Alternatively, after the imprint process is performed on as many substrates 9 as determined in advance, steps S1 to S4 can be performed again. For example, every time the imprint process is performed on 25 substrates 9, steps S1 to S4 can be performed again. Thus, the imprint process can be advanced while confirming that the substrates 9 do not vary due to individual differences between substrates 9, or are not influenced by preprocessing.
In step S5, the position adjustment between the mold 6 and the substrate 9 is made (a position adjustment step). As illustrated in
The position adjustment between the mold 6 and the substrate 9 is made by moving the wafer stage 4 in the XY-plane. As a result, it is also possible to perform the shearing force measurement in step S3. The shearing force measurement in step S3 may be performed simultaneously with the position adjustment step in step S5.
In step S6, the pattern formed in the imprint material 8 by the mold 6 is cured. The imprint head (not illustrated) emits, to the imprint material 8, light having a wavelength that cures the imprint material 8, thereby curing the imprint material 8. The light having the wavelength that cures the imprint material 8 may be an electromagnetic wave that cures the imprint material 8, such as ultraviolet light.
To pull the mold 6 away from the cured imprint material 8, the mold 6 is lifted in the +Z-direction, and the substrate 9 is carried out of the imprint apparatus 12.
In the imprint method as described above, the measurement result of the shearing force is fed back to the preprocessing apparatus, whereby it is possible to improve the accuracy of the position adjustment between the substrate 9 and the mold 6.
Next, an imprint method according to a second exemplary embodiment is described with reference to
In
As a measurement method performed by the measurement unit, optical measurement is desirable to prevent the contamination of the substrate 9. For example, spectroscopic ellipsometry is used. The base layer 1 may be a multilayer. In a case of a multilayer, the in-plane distribution of the film thickness of each layer is obtained as a measured value.
In step S8, the measured value of the in-plane distribution of the film thickness of the base layer 1 is fed back to the preprocessing apparatus (not illustrated). Based on information regarding the fed back in-plane distribution of the film thickness of the base layer 1, the preprocessing apparatus (not illustrated) determines the application condition of the base layer 1 and changes the current application condition to the determined application condition.
As described above, it has been found out that the shearing force acting on the imprint material 8 depends on the film thickness of the base layer 1. That is, if the film thickness of the base layer 1 is made larger, the shearing force acting on the imprint material 8 becomes smaller. In response, based on information regarding the distribution of the film thickness of the base layer 1, the application condition is determined such that the film thickness of the base layer 1 becomes uniform, and the current application condition is changed to the determined application condition, whereby it is possible to reduce the deviation of the difference in height in the distribution of the shearing force.
That is, the application condition of the base layer 1 can be set to an application condition having the distribution of the film thickness obtained by changing the film thickness of the base layer 1 such that the difference in height in the distribution of the shearing force between a plurality of areas on the substrate 9 becomes small.
Particularly, the application condition may be determined such that the film thickness of the base layer 1 increases in response to an increase in the shearing force generated in the peripheral direction from the center of the substrate 9.
There is also a case where a pattern is formed on the substrate 9 before the imprint apparatus 12 performs the imprint process. In such a case, even if the distribution of the film thickness of the base layer 1 is uniform on the substrate 9, the shearing force may be ununiformly distributed on the substrate 9.
It is considered that this distribution of the shearing force is caused by the unevenness of the pattern formed in advance.
In response, an optimal application condition may be determined based on information regarding both the distribution of the shearing force of the substrate 9 fed back to the preprocessing apparatus (not illustrated) in step S4 and the distribution of the film thickness of the base layer 1 fed back in step S8. In this case, priority may be given to the distribution of the shearing force, and the distribution of the film thickness of the base layer 1 may be positively provided.
In the imprint method as described above, it becomes possible to improve the accuracy of the position adjustment between the substrate 9 and the mold 6, by feeding back the measured value of the in-plane distribution of the film thickness of the base layer 1 to the preprocessing apparatus (not illustrated).
Next, an imprint method according to a third exemplary embodiment is described with reference to
In
The position adjustment of the mold 6 and the substrate 9 is performed by an alignment detection unit 40 detecting the mold alignment mark 3 and the substrate alignment mark 2. The alignment detection unit 40 includes a light emission device that illuminates the mold alignment mark 3 and the substrate alignment mark 2, and a detection unit that detects light reflected and scattered by both alignment marks.
If the film thickness of the base layer 1 becomes large, the light reflected and scattered by the mold alignment mark 3 and the substrate alignment mark 2 is absorbed by the base layer 1, and the detection intensity of the light being detected by the alignment detection unit 40 becomes weak. This results in decreasing the accuracy of the position adjustment. In response, the wavelength and the amount (the intensity) of the light to be emitted from the alignment detection unit 40 is optimized according to the film thickness of the base layer 1, based on information regarding the in-plane distribution of the film thickness of the base layer 1 fed forward in step S9.
The absorption of the light by the base layer 1 has wavelength dependence. Thus, the detection intensity of the light by the alignment detection unit 40 can be improved by selecting a wavelength that is less absorbed. If the intensity of the light to be emitted to the alignment marks is increased, the intensity of the light to be reflected and scattered by the alignment marks increases. Thus, the detection accuracy of the light by the alignment detection unit 40 is improved. The position adjustment between the substrate 9 and the mold 6 can be made with more accuracy by selecting the wavelength and the light intensity of alignment light based on information regarding the in-plane distribution of the film thickness of the base layer 1.
As described above, in the imprint method, the measured value of the in-plane distribution of the film thickness of the base layer 1 is measured, and based on the measurement result, a detection condition for subsequent alignment detection through the base layer 1 is determined. That is, the accuracy of the position adjustment between the substrate 9 and the mold 6 can be improved, by feeding forward the measurement result to the imprint apparatus 12.
Next, an imprint method according to a fourth exemplary embodiment is described with reference to
As illustrated in
A particle detection unit 50 includes an emission mechanism that emits light to particles, and a detection mechanism that detects the light reflected and scattered by the particles. The particle detection apparatus 53 includes a substrate stage (not illustrated). The particle detection apparatus 53 rotates the substrate 9 and performs XY scan on the substrate 9, and thereby can measure the distribution of particles on the base layer 1.
In step S2, the imprint apparatus 12 brings the mold 6 and the substrate 9 into contact with each other with the imprint material 8 between the mold 6 and the substrate 9. As illustrated in
In
The acceptable particle size depends on the film thickness of the base layer 1. In general, the base layer 1 is composed of a softer material than that of the mold 6. For example, quartz is used as the mold 6, and an organic substance, such as SOC, is used as the base layer 1. Even if particles are attached to the base layer 1, the base layer 1 functions as a cushion to prevent the mold 6 from being destroyed. If the film thickness of the base layer 1 becomes smaller, the function as a cushion becomes weaker. Thus, the base layer 1 can only prevent smaller particles from destroying the mold 6. The particle detection sensitivity of the particle detection apparatus 53 is increased so that particles of smaller sizes can be detected, whereby it is possible to prevent the mold 6 from being destroyed by particles. Meanwhile, the increase in the particle detection sensitivity also increases noise level. This causes a detection error. In response, based on the in-plane distribution of the film thickness of the base layer 1, the value of the acceptable particle size in the particle detection apparatus 53 is increased or decreased. In an area where the film thickness of the base layer 1 is large, particles of larger sizes are detected. In an area where the film thickness of the base layer 1 is small, particles of smaller sizes are detected. This can reduce noise level while preventing the mold 6 from being destroyed by particles.
In the imprint method as described above, the measured value of the in-plane distribution of the film thickness of the base layer 1 is measured, and based on the measurement result, a detection condition for particle detection through the base layer 1 is determined. That is, it becomes possible to prevent the mold 6 from being destroyed by particles and to improve the accuracy of the position adjustment between the substrate 9 and the mold 6, by feeding back the measurement result to the particle detection apparatus 53.
Next, a description is given of a method for manufacturing an article (e.g., a semiconductor integrated circuit (IC) element, a liquid crystal display element, and microelectromechanical systems (MEMS)) using the imprint apparatus. The article is manufactured using the mold by performing the step of imprinting a substrate (e.g., a wafer, and a glass substrate) to which a photosensitizing agent is applied, the step of exposing the substrate, the step of developing the substrate (the photosensitizing agent), and the step of processing the developed substrate in other known steps. The processing in the other known steps includes etching, imprint material removal, dicing, bonding, and packaging. According to this article manufacturing method, a higher-grade article can be manufactured than that manufactured by a conventional method.
While desirable exemplary embodiments of the present disclosure have been described above, the present disclosure is not limited to these exemplary embodiments, but can be modified and changed in various manners within the scope of the present disclosure.
According to the present disclosure, it is possible to provide a molding method having an advantage in the position adjustment between a substrate and a mold in a plurality of different areas on the substrate.
While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the disclosure 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. 2019-059215, filed Mar. 26, 2019, which is hereby incorporated by reference herein in its entirety.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-059215 | Mar 2019 | JP | national |
