WO2017086246A1

WO2017086246A1 - Imprint apparatus, and method of manufacturing article

Info

Publication number: WO2017086246A1
Application number: PCT/JP2016/083495
Authority: WO
Inventors: Setsuo Yoshida
Original assignee: Canon Kabushiki Kaisha
Priority date: 2015-11-16
Filing date: 2016-11-11
Publication date: 2017-05-26
Also published as: KR102103288B1; KR102238990B1; JP6774178B2; KR20200043512A; KR20180080308A; JP2017092396A

Abstract

An imprint apparatus that forms a pattern of an imprint material on a substrate using a mold is provided. The imprint apparatus includes a substrate holder including a plurality of chucking regions which chuck a substrate and a controller which independently controls the chucking forces of the plurality of chucking regions. The controller partially weakens the chucking forces of the plurality of chucking regions in accordance with the progression of mold separating in which the mold is separated from the imprint material.

Description

IMPRINT APPARATUS, AND METHOD OF MANUFACTURING ARTICLE

The present invention relates to an imprint apparatus and a method of manufacturing an article.

In an imprint apparatus, when mold separating of separating a mold from an imprint material that has been cured on a substrate is performed, a large separation stress is applied instantaneously on the interface (contact portion) between the mold and the cured imprint material. This stress may distort the pattern to be formed and lead to a pattern defect. In U.S. Patent Application Publication No. 2007-0114686, the mold is temporarily deformed into a convex shape toward the substrate, and the mold is gradually separated from the periphery of a pattern formation portion of the imprint material to avoid the abrupt generation of stress at the time of mold separating. Additionally, in U.S. Patent Application Publication No. 2006-0172031 and U.S. Patent Application Publication No. 2010-0102469, the chucking pressure of a chuck which is a substrate holder is weakened to cause the substrate to rise from the chuck when separating the mold at the time of mold separating. As a result, the stress generated on the interface of the mold 1 and the imprint material is reduced, and defects due to pattern distortion are reduced.

If the imprint method is to be applied to the manufacture of a semiconductor device, an image sensor, or a display panel, the throughput can be improved by imprinting a maximum area at once. In this case, the area where the mold and the imprint material are in contact with each other becomes large.

In a case in which a large area is to be imprinted at once as described above, a large area mold will be separated from the imprint material at the time of mold separating. At this time, in accordance with the related art, assume a case in which the chucking pressure of the chuck that chucks and holds a substrate is weakened at the time of mold separating and the substrate is caused to rise from the chuck. For example, when a shot region arranged on the entire surface of the substrate is to be imprinted at once, if the chucking pressure of the chuck is decreased at the time of mold separating to cause the substrate to rise from the chuck, the mold and the substrate will be deformed. In particular, when mold separating is started, first, a mold 51 and a resin 52 which is the cured imprint material start to separate from the edge of a wafer 53 as the substrate, and the mold 51 and the wafer 53 are deformed. In accordance with the progression of mold separating, the mold 51 and the resin 52 begin to separate toward the center from the edge of the wafer 53, and the mold 51 and the resin 52 are deformed as shown in Fig. 9 before the completion of the mold separating. In state 902 in Fig. 2, when the portion near the center of the wafer 53 is separated, the portion near the edge of the wafer 53 is in contact with a chuck 54 and the center portion is deformed into a convex shape toward the mold, and the mold 51 is deformed into a convex shape toward the substrate. Since the range in which the wafer 53 is caused to rise from the chuck 54 is wide, the deformation of the mold 51 and the mold 53 becomes large.

As a result, problems such as damage to the mold and substrate members and a defect of an imprint material pattern formed on a substrate occur. In addition, since the range in which the wafer 53 is caused to rise from the chuck 54 is wide, it becomes problematically easy for the wafer 53 to fall from the chuck 54.

In order to avoid these problems, the chucking pressure of the wafer 53 to the chuck 54 can be increased to make the area where the wafer 53 rises from the chuck 54 small. However, the effect of reducing the stress generated on the interface of the aforementioned mold and imprint material becomes small, and the effect of reducing pattern defect becomes also small.

The present invention provides, for example, a technique advantageous in preventing damage due to deformation of a mold and a substrate, preventing the substrate from falling off a substrate holder, and suppressing a pattern distortion and defect.

According to one aspect of the present invention, an imprint apparatus that forms a pattern of an imprint material on a substrate by using a mold is provided. The apparatus comprises a substrate holder which includes a plurality of chucking regions configured to chuck the substrate, and a controller configured to independently control each of chucking forces of the plurality of chucking regions. The controller partially weakens the chucking forces of the plurality of chucking regions in accordance with the progression of mold separating in which the mold is separated from the imprint material.

Further features of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).

Fig. 1 is a view showing the arrangement of an imprint apparatus according to an embodiment. Fig. 2A is a view showing the arrangement of a substrate holder according to the embodiment. Fig. 2B is a view showing the arrangement of a substrate holder according to the embodiment. Fig. 3 is a view showing the arrangement for holding and releasing the substrate by the substrate holder according to the embodiment. Fig. 4 is a view for explaining an imprint process according to the embodiment. Fig. 5 is a view for explaining an example of imprinting at once a plurality of pattern regions which are not adjacent to each other on a substrate. Fig. 6 is a view for explaining an imprint process according to an embodiment. Fig. 7 is a view showing the arrangement of a substrate holder according to the embodiment. Fig. 8 is a view showing the arrangement of a substrate holder according to an embodiment. Fig. 9 is a view for explaining an imprint process according to a related art.

Various exemplary embodiments, features, and aspects of the invention will be described in detail below with reference to the drawings. Note that the following embodiments are not intended to limit the present invention and are merely concrete examples advantageous in practicing the invention. Also, not all combinations of features to be described in the embodiments are indispensable for the means to solve the problems according to the present invention.

(First Embodiment)
Fig. 1 is a view showing the arrangement of the imprint apparatus according to this embodiment. In this embodiment, the imprint apparatus adopts a photo-curing method of curing an imprint material by ultraviolet light irradiation. However, the present invention is not limited to this and can adopt a heat-curing method of curing an imprint material by application of heat.

The imprint apparatus forms an imprint material on a substrate by using a mold on which a pattern has been formed. As shown in Fig. 1, a substrate holder 5 is arranged on a substrate stage 7, and a substrate 2 has been chucked on the substrate holder 5. For the substrate 2, although misalignment information is obtained first by observing an alignment mark on the substrate 2 by an alignment optical system (not shown), a distance from a height measurement device 15 to the upper surface of the substrate 2 is simultaneously measured by the height measurement device 15. On the other hand, a mold 1 is held by a mold holder 4, and since the relative height between the pattern surface of the mold 1 and the height measurement device 15 is measured in advance, it is possible to calculate the distance from the upper surface of the substrate 2 to the pattern surface of the mold 1. A dispenser 14 supplies a photo-curing resin as an imprint material 3 on the substrate 2. When the mold 1 is lowered by a driving device 12 and is brought into contact with the imprint material 3 supplied on the substrate 2, the imprint material 3 flows into the grooves engraved in the pattern. The mold 1 is formed from a material which is transparent to the light (ultraviolet light) that cures the imprint material. The ultraviolet light emitted from a light source 20 is reflected by a half mirror 19 and enters the imprint material 3 on the substrate 2 by passing through the mold 1. In this manner, the imprint material irradiated with ultraviolet light is cured. Subsequently, the mold 1 is raised by the driving device 12 to separate the mold 1 from the cured imprint material 3, and an inverted image of the pattern of the mold 1 is formed on the substrate by the cured imprint material. An observation optical system 18 is a scope to observe the entire shot region of the substrate 2. The observation optical system 18 is used to confirm the state of the imprint process, for example, the pressing state of the mold 1 and the filling state of the imprint material 3. A controller 50 comprehensively controls the respective units related to the imprint process.

The above described driving device 12 is a mechanism that moves the mold 1 upward/downward with respect to the substrate 2. However, it is sufficient to use a mechanism that can relatively change the spacing between the mold 1 and the substrate 2. For example, it may be a mechanism that moves the mold 1 upward/downward with respect to the substrate 2 or it may include a mechanism that moves the mold 1 and the substrate 2 upward/downward independently.

The substrate holder 5 holds the substrate 2 by, for example, a vacuum chuck. Fig. 2A is a view showing the substrate holder 5 viewed from the side of the mold 1. As shown in Fig. 2A, in the substrate holder 5, a plurality of chucking regions 5a to 5i (partial holding region) are formed concentrically on the surface that contacts the lower surface of the substrate 2. Fig. 3 shows a sectional view taken along a line A - A’ in Fig. 2A. Each of the plurality of chucking regions 5a to 5i is connected to a corresponding air pressure adjustment mechanism (illustration of the connection arrangement of the chucking regions 5c to 5i has been omitted in Fig. 3). Here, the chucking region 5a will be described as a representative example. A pipe 31 is connected to the chucking region 5a. The pipe 31 is bifurcated midway by a flow path switching valve 32. One side is connected to a vacuum pump (not shown) via a regulator 33, and the other side is connected to a compressor (not shown) via a regulator 34.

When vacuum chucking the substrate 2, the controller 50 switches the flow path switching valve 32 to the side of the vacuum pump. As a result, the air in the chucking region 5a is sucked into the vacuum pump via the pipe 31, the flow path switching valve 32, and the regulator 33, and the pressure inside the chucking region 5a is changed to a negative pressure to chuck the substrate 2. At this time, the regulator 33 can control the chucking force (the substrate drawing force and the substrate holding force of the substrate holder 5) under the control of the controller 50.

When the chucking and holding of the substrate 2 is to be canceled, the controller 50 switches the flow path switching valve 32 to the side of the compressor. As a result, the air from the compressor is supplied to the chucking region 5a via the regulator 34, the flow path switching valve 32, and the pipe 31, and the pressure inside the chucking region 5a is changed to a positive pressure to release the substrate 2 from the substrate holder 5.

The other chucking regions 5b to 5i each have the same arrangement as that of the chucking region 5a, and a description thereof will be omitted. In this manner, the substrate holder 5 according to this embodiment has an arrangement in which the chucking force of each of the plurality of the chucking regions 5a to 5i can be independently controlled.

An imprint process according to this embodiment will be described next with reference to Fig. 4. This embodiment assumes a case in which a shot region pattern corresponding to the entire surface of the substrate 2 is formed on the mold 1 and imprinting is performed at once on the entire surface of the substrate 2. This embodiment can form an imprint material pattern on the substrate 2 by a single imprint process. In addition, in this embodiment, a sealed space A is formed between the upper portion of the mold 1 and the mold holder 4, and the air pressure inside the sealed space A can be adjusted by a pressure adjuster 6 under the control of the controller 50. A state 401 in Fig. 4 represents the initial state before the start of the imprint process. At this time the sealed space A is set to the state of atmospheric pressure.

When the pattern portion of the mold 1 is brought into contact with the imprint material 3 coated on the substrate 2, the pressure adjuster 6 applies pressure in the sealed space A to deform the mold 1 into a convex shape toward the substrate 2. This state is shown as a state 402 in Fig. 4. Subsequently, the mold 1 is brought closer to the substrate 2 by the driving device 12, and as the pattern portion of the mold 1 is brought into contact with the imprint material 3 on the substrate 2, the pressure in the sealed space A is lowered accordingly, and the mold is changed back to a flat surface. This state is shown as a state 403 in Fig. 4. As a result, the gas between the mold 1 and the imprint material 3 is sequentially pushed outside, and mixing of air bubbles between the mold 1 and the imprint material 3 is prevented.

Next, after curing the imprint material 3 by irradiating the imprint material 3 on the substrate 2 with the ultraviolet light from the light source 20, mold separating of separating the mold 1 from the cured imprint material 3 is performed by the driving device 12. If the mold 1 is separated linearly in a direction (z direction) perpendicular to the extending direction of the substrate 2, the mold 1 receives a pulling force toward the substrate 2 and is deformed into a bowl shape as shown in the state 403 in Fig. 4. As a result, the mold 1 and the imprint material 3 start to separate from the outermost periphery of the substrate 2 and continue to separate toward the center of the substrate 2 as the distance between the mold 1 and the substrate 2 increases. At this time, the exact positions (separation positions) where the mold 1 and the imprint material 3 are trying to separate from each other are concentric to the periphery of the substrate 2. When the chucking forces of the chucking regions of the substrate holder 5 which are immediately below the separation positions are lower than those of the other chucking force regions, the portions of the substrate 2 near the separation positions rise from the substrate holder 5 as shown in a state 404 in Fig. 4. As a result, stress generated on the interface of the mold 1 and the imprint material 3 is reduced, and defects due to pattern distortion can be reduced.

As the mold separating proceeds, the separation positions move from the periphery to the center of the substrate 2. When a pattern is formed on the entire surface of the substrate by a single imprint operation in this manner, the separation positions change from the periphery to the center of the substrate 2 in accordance with the mold separating. Hence, in this embodiment, in accordance with the progression of the mold separating, each chucking force is weakened by sequentially adjusting the regulator 33 of each chucking region from the peripheral-side chucking region toward the chucking region in the center. For example, the regulator 33 of a chucking region immediately below each separation position is adjusted. After each chucking force is temporarily weakened, the chucking force is returned to its original force after an assumed separation completion time at each separation position has elapsed. As a result, only portions of the substrate 2 near the separation positions rise from the substrate holder 5, and the problem in which the substrate 2 falls from the substrate holder 5 hardly occurs. In addition, since deformation of the mold 1 and the substrate 2 also becomes small, the possibility that each member will be damaged due to deformation can be reduced.

According to the above-described embodiment, in a case in which the entire surface of the substrate is imprinted at once, pattern defects can be reduced without damage due to deformation of the mold and the substrate and the occurrence of the substrate falling from the substrate holder.

Note that the above-described embodiment assumes a case in which the entire surface of the substrate 2 is imprinted at once. However, the present invention is also applicable to a case in which the substrate is divided into partial regions and imprinted for each partial region. For example, as shown in Fig. 2B, a plurality of chucking regions which are concentrically divided and formed may be provided in each of the plurality of partial regions, and the chucking pressure of each region may be controlled at the time of mold separating in the same manner as that described above. As a result, partial control of chucking force in each partial region becomes possible for a case in which imprinting is performed for each partial region of the substrate.

Additionally, in the above-described embodiment, the plurality of chucking regions of the substrate holder have been concentrically divided and formed. However, it is sufficient as long as the regions are divided so that the exterior shape sequentially includes the interior shape, and it need not be a circle but may be another shape such as an oval or a polygon.

There also exists a method in which the throughput is improved by forming a plurality of patterns that are not adjacent to each other on the mold 1 and performing the imprint process at once on the plurality of patterns. Fig. 5 is a top view of the substrate 2 in this case. As shown in Fig. 5, the imprint process is performed at once on a plurality of pattern regions 2a that are not adjacent to each other. Here, if the distance between the pattern regions 2a is increased, the same problem as that when a large area is imprinted at once can occur. However, according to this embodiment, in the same manner as the above-described example, pattern defects can be reduced without damage due to deformation of the mold and the substrate and the occurrence of the substrate falling from the substrate chuck.

Note that although the embodiment has an arrangement in which the substrate holder 5 holds the substrate 2 by vacuum chuck, it may also have an arrangement in which the substrate 2 is held by another method such as electrostatic chuck.

(Second Embodiment)
An imprint process according to the second embodiment will be described next. Components that have been described in the first embodiment are given common reference numerals, and a description thereof will be omitted.

Fig. 7 is a view showing a substrate holder 5 viewed from the side of a mold 1. As shown in Fig. 7, a plurality of chucking regions divided by a plurality of lines parallel to the center line of a substrate 2 have been formed on the surface contacting the substrate 2. This substrate holder 5 can independently control each of the chucking forces of the plurality of the chucking regions by the same arrangement as that shown in Fig. 3.

In this embodiment, steps from when the mold is brought into contact with the imprint material 3 on the substrate 2 until the subsequent curing of imprint material 3 are the same as those in the first embodiment. Subsequently, at the time of mold separating, the mold 1 is separated from only one edge of the substrate 2 by a driving device 12 as shown in a state 601 in Fig. 6. As a result, the mold 1 and the imprint material 3 start separating from one edge of the substrate 2. Furthermore, as the distance between the mold 1 and the substrate 2 is increased, the mold 1 and the imprint material 3 continue to separate toward the other edge from the one edge where the separation started. At this time, the separation positions of the mold 1 and the imprint material 3 are parallel to the center line of the substrate 2 having a circular shape. When the chucking force of the chucking region of the substrate holder 5 which is immediately below the separation position is lower than those of the other chucking force regions, the portion of the substrate 2 near the separation position rise from the substrate holder 5 as shown in a state 602 in Fig. 6. As a result, stress generated on the interface of the mold 1 and the imprint material 3 is reduced, and defects due to pattern distortion can be reduced in the same manner as the first embodiment. In addition, the effect of preventing damage due to deformation of the mold and the substrate and the occurrence of the substrate falling from the substrate holder is the same as the first embodiment.

(Third Embodiment)
Fig. 8 is a view showing a substrate holder 5 viewed from the side of a mold 1 according to the third embodiment. Other arrangements of an imprint apparatus according to this embodiment are the same as those in the above-described first and second embodiments. As shown in Fig. 8, a plurality of chucking regions divided to be in a lattice form have been formed on the surface that contacts the substrate 2. Note that the division shape of the plurality of chucking regions is not limited to be in a lattice form and may be any shape. This substrate holder 5 can independently control each of the chucking forces of the plurality of the chucking regions by the same arrangement as that shown in Fig. 3.

In this embodiment, mold separating is performed after the mold 1 is brought into contact with an imprint material 3 on the substrate 2 and the imprint material 3 is cured. At this time, the mold 1, in the same manner as in the first embodiment, starts to separate from the imprint material 3 on the substrate 2 from the outermost periphery of the substrate 2, and as the mold separating proceeds, the separation positions form an annular shape and move from the periphery toward the center of the substrate 2. In synchronization with this operation, the chucking forces of the respective chucking regions forming the annular shape immediately below the separation positions of the substrate holder 5 are weakened as shown in the hatched line portion chucking regions in Fig. 8. As a result, only the portions of the substrate 2 near the separation positions rise from the substrate holder 5. As described above, in the same manner as the first embodiment, the effect of reducing defects due to pattern distortion can be achieved, and the damage due to deformation of the mold and substrate and the problem of the substrate falling from the chuck can be suppressed.

In addition, according to this embodiment, when the mold separating of separating only one edge of the mold 1 or the substrate 2 is performed in the same manner as the second embodiment, the separation positions of the mold 1 and the imprint material 3 are parallel to the center line of the substrate 2. At this time, the same effect as that in the second embodiment is obtained by weakening the chucking forces of the linear chucking regions of the substrate holder 5 that are located immediately below the separation positions.

Furthermore, in this embodiment, the combination of regions in which the chucking forces of the substrate holder 5 are to be weakened can be arbitrarily changed. Hence, the embodiment is advantageous in that the same substrate holder can cope with a case in which the entire surface of the substrate is to be imprinted at once and a case in which a partial region of the substrate is to be imprinted.

If the shape of the chucking regions of the substrate holder 5 is not similar to the shape of the pattern region of the mold 1, the distribution of mold separating forces can be nonuniform and the mold separating speed can be uneven. Hence, mold separating is performed by controlling the driving device 12 so as to keep the mold 1 and the substrate 2 parallel to each other. In addition, when separating the mold, along with the gradual decrease in the area of the pattern region of the mold 1 which is in contact with the imprint material, the mold separating speed can be controlled to be constant rather than the driving device 12 controlling the mold separating by a constant force. Defects that may occur at the time of mold separating can be suppressed by performing such control.

(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 transferring the pattern of an original onto a substrate using the above-described lithography apparatus (an exposure apparatus, an imprint apparatus, a drawing apparatus, or the like), and a step of processing the substrate onto which the pattern has been transferred in the preceding step. This manufacturing method further includes other known steps (oxidation, deposition, vapor deposition, doping, planarization, etching, resist removal, 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.

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. 2015-224226, filed November 16, 2015, which is hereby incorporated by reference wherein in its entirety.

Claims

An imprint apparatus that forms a pattern of an imprint material on a substrate by using a mold, comprising:
a substrate holder which includes a plurality of chucking regions configured to chuck the substrate; and
a controller configured to independently control each of chucking forces of the plurality of chucking regions,
wherein the controller is configured to partially weaken the chucking forces of the plurality of chucking regions in accordance with the progression of mold separating in which the mold is separated from the imprint material.
The apparatus according to claim 1, wherein the controller is configured to partially weaken the chucking forces of the plurality of chucking regions in synchronization with the movement of position where the mold is separated from the imprint material at the time of mold separating.
The apparatus according to claim 2, wherein the controller is configured to set, out of the plurality of chucking regions, a lower chucking force of a chucking region immediately below the position where the mold is separated from the imprint material than those of the other chucking regions at the time of mold separating.
The apparatus according to any one of claims 1 to 3, wherein a pattern corresponding to the entire surface of the substrate is formed on the mold, and the pattern of the imprint material is formed at once on the entire surface of the substrate.
The apparatus according to claim 4, wherein the plurality of chucking regions are concentrically divided, and
the controller is configured to sequentially weaken the chucking forces, out of the plurality of chucking regions concentrically formed, from a chucking region on a peripheral side toward the center of the chucking region, as the mold is separated from the outside of the substrate toward the center.
The apparatus according to claim 4, wherein the plurality of chucking regions are divided by a plurality of lines parallel to a center line of the substrate having a circular shape, and
the controller is configured to sequentially weaken a chucking force, out of the plurality of chucking regions, from a chucking region on one edge toward another edge, as the mold is separated from the one edge of the substrate toward the other edge.
The apparatus according to any one of claims 1 to 3, wherein the substrate holder includes, for the plurality of partial regions, the plurality of chucking regions that have been concentrically divided.
The apparatus according to claim 7, a plurality of patterns which are not adjacent to each other are formed on the mold, and the pattern of the imprint material is formed at once on regions corresponding to the plurality of regions on the substrate.
The apparatus according to any one of claims 1 to 3, wherein the plurality of chucking regions are divided in a lattice form.
A method of manufacturing an article, comprising:
forming a pattern of an imprint material on a substrate using an imprint apparatus; and
processing the substrate on which the pattern has been formed by the forming,
wherein the imprint apparatus forms the pattern of an imprint material on a substrate by using a mold and includes
a substrate holder which includes a plurality of chucking regions configured to chuck the substrate; and
a controller configured to independently control each of chucking forces of the plurality of chucking regions, and
wherein the controller partially weakens the chucking forces of the plurality of chucking regions in accordance with the progression of mold separating in which the mold is separated from the imprint material.