Lithography apparatus, and method of manufacturing article

The present invention provides a lithography apparatus that performs patterning on a substrate using an original, the apparatus including a supply device configured to supply a gas to a space between the substrate and the original, a chuck configured to hold the substrate, a movable device that holds the chuck and is movable, and a plate provided on the movable device and surrounding the chuck, wherein the chuck includes a first edge, on a side of the chuck facing the original, protruding toward the plate.

BACKGROUND OF THE INVENTION

Field of the Invention

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

Description of the Related Art

There is known an imprint apparatus as a lithography apparatus used for manufacturing semiconductor devices. The imprint apparatus is required to improve the filling property of the imprint material to a pattern formed on a mold from the viewpoints of productivity and accuracy of patterns formed on the substrate. Thus, in Japanese Patent Laid-Open No. 2013-175631, there is proposed a technique of performing an imprint process in a state in which the air in a space between the mold and the substrate (imprint material) is substituted with a gas such as helium or pentafluoropropane.

Furthermore, as disclosed in Japanese Patent No. 4961299, a protection plate (also called a flush plate) is arranged on a substrate holding unit (substrate stage) so that the upper surface of the substrate and the upper surface of the flush plate are flush and so as to surround the periphery of the substrate. The arrangement of such a protection plate in the imprint apparatus allows a mold to maintain a state facing the substrate or the protection plate even if the substrate is moved within the plane to perform an imprint process in each imprint region of the substrate. Hence, it is advantageous in maintaining a constant concentration of a gas in the space between the mold and the substrate.

However, if a gas is supplied to the substrate and the protection plate from a gas supply unit arranged in the upper side of the substrate holding unit, the gas flows to a space below a chuck via a gap between the protection plate and the chuck that holds the substrate. Therefore, it becomes difficult to maintain a constant concentration of a gas in the space between the mold and the substrate without changing the flow rate of the gas supplied from the gas supply unit. Note that the space is provided below the chuck to insert a robot hand for replacing (collecting) the chuck.

SUMMARY OF THE INVENTION

The present invention provides, for example, a lithography apparatus advantageous in adjusting of concentration of a gas in a space between an original and a substrate.

According to one aspect of the present invention, there is provided a lithography apparatus that performs patterning on a substrate using an original, the apparatus including a supply device configured to supply a gas to a space between the substrate and the original, a chuck configured to hold the substrate, a movable device that holds the chuck and is movable, and a plate provided on the movable device and surrounding the chuck, wherein the chuck includes a first edge, on a side of the chuck facing the original, protruding toward the plate.

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

DESCRIPTION OF THE EMBODIMENTS

Preferred 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.

FIG. 1is a schematic view showing the arrangement of an imprint apparatus1as an aspect of the present invention. The imprint apparatus1is a lithography apparatus that forms a pattern on a substrate by using an original. In this embodiment, the imprint apparatus1is implemented as an apparatus that performs an imprint process of molding an imprint material on a substrate by using a mold and forming a pattern on the substrate.

This embodiment assumes a photo-curing resin material as an imprint material and adopts a photo-curing method of curing the imprint material by irradiation with light (such as ultraviolet light). However, the present invention does not limit the imprint material to a resin material, and the material may be, for example, a photo-curing material including an inorganic powder or particles. Also, the curing method of the imprint material is not limited to a photo-curing method. For example, a heat-curing method of curing an imprint material by application of heat may be adopted.

The imprint apparatus includes, as shown inFIG. 1, a main body structure11, a light source12, an illumination optical system13, a mold driving unit14, a mold chuck15, a stage platen17, a substrate stage18, a substrate chuck19, a gas supply unit21, and a protection plate23. The entire imprint apparatus1is housed in a chamber (not shown), and a constant atmosphere is maintained inside the chamber. Additionally, in the following description, a direction along the optical axis of the illumination optical system13which irradiates the imprint material on the substrate with light is set as the Z-axis, and directions orthogonal to each other in a plane perpendicular to the Z-axis are set as the X-axis and the Y-axis.

The main body structure11has a highly rigid structure. The light source12, an illumination optical system13, the mold driving unit14, and the stage platen17are installed in the main body structure11. The light source12includes a halogen lamp that generates ultraviolet light. The illumination optical system13which includes a lens, an aperture, and a shutter irradiates the imprint material supplied on substrate with light to cure the imprint material.

The mold driving unit14holds a mold16via the mold chuck15and can be driven in the Z, ωX, and ωY directions. Sensors (not shown) which measure the positions of the mold driving unit14in the Z, ωX, and ωY directions are provided in the imprint apparatus1. The position of mold driving unit14is controlled based on the measurement results of the sensors.

The mold16is an original which includes a three-dimensional pattern on the surface that faces a substrate20and is formed from a light passing material to cure the imprint material on the substrate. The mold16is loaded from outside the imprint apparatus1by a mold conveying system and is held by the mold chuck15.

The substrate stage18is placed (mounted) on the stage platen17. The substrate stage18holds the substrate chuck19that chucks and holds the substrate20and can be driven in the X, Y, and θz directions. In this embodiment, the substrate stage18is a movable device movable while holding (chucking) the substrate chuck19. Sensors (not shown) which measure the positions of the substrate stage18in the X, Y, and θz directions are provided in the imprint apparatus1. The position of substrate stage18is controlled based on the measurement results of the sensors.

The substrate20is a substrate to which the pattern of the mold16is transferred and includes, for example, a single crystal silicon substrate or an SOI (Silicon on Insulator) substrate. The imprint material is supplied (applied) on the substrate20from a supply unit including a dispenser. The substrate20is loaded from outside the imprint apparatus1by a substrate conveying system and is held by the substrate chuck19.

The gas supply unit21is arranged around the mold16, supplies a gas22to an imprint space SP between the mold16and the substrate20(protection plate23), and substitutes (fills) the air in the imprint space SP with the gas22. The gas22includes a permeable gas having a dissolving or diffusing property with respect to at least one of the mold16, the substrate20, and the imprint material or a condensable gas having a property of being condensed and liquefied by pressure application when molding the imprint material. The gas22includes, for example, helium or pentafluoropropane. By substituting the air in the imprint space SP with the gas22, the filling property of the imprint material to the pattern of the mold16when molding the imprint material on the substrate by the mold16can be improved.

The protection plate23is provided on the substrate stage18and surrounds the substrate chuck19. The protection plate23is formed so that its surface (the surface on the side of the original) is almost flush with the surface of the substrate20held by the substrate chuck19. When an imprint process is performed on a shot region (partial field) which includes an edge portion of the substrate20, the gas22is supplied in a state in which the gas supply unit21faces the substrate20and the protection plate23. Since the volume change of the imprint space SP where the gas22is to be supplied can be minimized by arranging the protection plate23, the change in the concentration of the gas in the imprint space can be suppressed. Hence, the filling property of the imprint material to the pattern of the mold16can be ensured.

In addition, in the imprint apparatus1, a sensor (not shown) which measures the Z-direction position of the substrate20held by the substrate chuck19is installed in the main body structure11. Furthermore, a sensor (not shown) which measures the Z-direction position of the mold16held by the mold chuck15is installed in the substrate stage18.

FIG. 2Ais a top view of the substrate chuck19.FIG. 2Bshows a cross section of the substrate chuck19taken in a direction (Z direction) perpendicular to the surface of the substrate20, that is, a cross-sectional view of the substrate chuck19taken along α-α shown inFIG. 2A. As described above, the substrate chuck19is placed on the substrate stage18and is, for example, held by the substrate stage18by being chucked by a vacuum pressure. The protection plate23is arranged outside the substrate chuck19.

The substrate chuck19is formed from ceramics such as silicon carbide or alumina. As shown inFIG. 2B, a concave portion (recess)191for placing (holding) the substrate20is formed on the surface on the side of the mold16of the substrate chuck19. For example, the substrate chuck19chucks and holds the substrate20placed in the concave portion191by a vacuum pressure. Concave portions (recesses)193for placing magnetic members192are also formed on the surface on the side of the mold16of the substrate chuck19. In this embodiment, the concave portions193are formed at three locations at equal angles on the peripheral portion of the surface on the side of the mold16of the substrate chuck19. The magnetic member192is placed in each of the concave portions193, and the magnetic member192is fastened to the concave portion193(substrate chuck19) via a corresponding fastening member194such as a bolt. In a state in which the substrate20is placed on the concave portion191, the surface of the substrate20, the surface on the side of the mold16of the substrate chuck19, the surface on the side of the mold16of the magnetic member192placed in each concave portion193, and the surface of the protection plate23are flush (form a single plane).

The substrate chuck19also includes, as shown inFIG. 2B, a first edge portion195protruding toward the protection plate23in the portion on the side of the mold16. InFIG. 2B, a portion including the first edge portion of the substrate chuck19and the first edge portion195are formed from a single member. The first edge portion195functions as the protection plate23. On the other hand, the protection plate23includes a second edge portion231protruding toward the substrate chuck19in its portion on the side of the substrate stage18. In this embodiment, the substrate chuck19is held by the substrate stage18so that the first edge portion195and the second edge portion231face each other in a direction perpendicular to the surface on which the substrate chuck19holds the substrate20. Note that there is a very small gap between the first edge portion195and the second edge portion231in the Z direction.

The outer diameter (external diameter) of the side surface of the substrate chuck19differs between its upper portion (on the side of the mold16) and lower portion (on the side of the substrate stage18) in a cross section taken in a direction perpendicular to the holding surface in which the substrate chuck19holds the substrate20. More specifically, the substrate chuck19is designed so that a dimension a of the outer diameter of the first edge portion195is larger than a dimension b of the outer diameter of a portion196on the side of the substrate stage18(a>b). The inner diameter of the side surface of the protection plate23differs between its upper portion and lower portion in a cross section taken in a direction perpendicular to the holding surface on which the substrate chuck19holds the substrate20. More specifically, the protection plate23is designed so that a dimension A of the inner diameter of a portion232on the side of the mold16is larger than a dimension B of the inner diameter of the second edge portion231(A>B). Furthermore, the substrate chuck19and the protection plate23are designed so that the dimension a of the outer diameter of the first edge portion195is larger than the dimension B of the inner diameter of the second edge portion231(a>B) in a cross section taken in a direction perpendicular to the holding surface on which the substrate chuck19holds the substrate20.

A channel (flow path) CH for the gas22supplied from the gas supply unit21to the imprint space SP is formed between the substrate chuck19and the protection plate23by such an arrangement. The conductance of a portion, of the channel CH, where the first edge portion195and the second edge portion231face each other is smaller than the conductance of the remaining portion. More specifically, a bent portion CHa which decreases the conductance of one portion of the channel CH compared to the other portion of the channel CH is formed on the one portion of the channel CH by the first edge portion195and the second edge portion231, thereby preventing the channel CH from becoming straight. As a result, when the gas22supplied to the imprint space SP flows out, that is, leaks to a space (not shown) below the substrate chuck19via the channel CH, the leak amount can be suppressed.

Additionally, in this embodiment, the substrate chuck19is designed so that the dimension b of the outer diameter of the portion196is larger than the outer diameter of a region of the holding surface for holding the substrate20in a cross section taken in a direction perpendicular to the holding surface on which the substrate chuck19holds the substrate20. Note that the region of the holding surface for holding the substrate20corresponds to the inner diameter of the concave portion191inFIG. 2B. Hence, it is possible to suppress the reduction in the flatness of the substrate20held by the substrate chuck19.

Another example of the arrangement of the substrate chuck19will be described with reference toFIG. 3.FIG. 3is a cross-sectional view of the substrate chuck19shown inFIG. 2Ataken along a line α-α′. InFIG. 3, the first edge portion195and a portion excluding the first edge portion195of the substrate chuck19are formed from separate members, and the first edge portion195is implemented as a ring plate198. The ring plate198is arranged outside a placement surface for placing the substrate20, that is, it is arranged so as to surround the placement surface and fastened to the substrate chuck19via a fastening member199such as a bolt. The ring plate198functions as the protection plate23. The substrate chuck19is held by the substrate stage18so that the ring plate198and a second edge portion231′ overlap. Note that there is a very small gap between the ring plate198and the second edge portion231′ in the Z direction.

Concave portions (recesses)198afor placing the magnetic members192are formed in the surface on the side of the mold16of the ring plate198. The concave portions198aare formed in three locations at equal angles on the ring plate198. The magnetic member192is placed in each of the concave portions198a, and the magnetic member192is fastened to the substrate chuck19via the fastening member194such as a bolt. In a state in which the substrate20is placed on the placement surface, the surface of the substrate20, the surface on the side of the mold16of the ring plate198, the surface on the side of the mold16of the magnetic member192placed in each concave portion198a, and the surface of the protection plate23are flush (form a single plane).

The outer diameter of the side surface of the substrate chuck19differs between its upper portion and lower portion in a cross section taken in a direction perpendicular to the holding surface on which the substrate chuck19holds the substrate20. More specifically, the substrate chuck19is designed so that a dimension d of the outer diameter of the ring plate198is larger than a dimension e of the outer diameter of a portion196′ on the side of the substrate stage18(d>e). The inner diameter of the side surface of the protection plate23differs between its upper portion and lower portion in a cross section taken in a direction perpendicular to the holding surface on which the substrate chuck19holds the substrate20. More specifically, the protection plate23is designed so that a dimension D of the inner diameter of a portion232′ on the side of the mold16is larger than a dimension E of the inner diameter of the second edge portion231′ (D>E). Furthermore, the substrate chuck19and the protection plate23are designed so that the dimension d of the outer diameter of the ring plate198is larger than the dimension E of the inner diameter of the second edge portion231′ (d>E) in a cross section taken in a direction perpendicular to the holding surface on which the substrate chuck19holds the substrate20.

Since this kind of arrangement eliminates the need to form the concave portion191for the placement of the substrate20on the substrate chuck19, it is comparatively easy to form a placement surface for placing the substrate20on the substrate chuck19. Note that the substrate chuck19, the magnetic members192, and the ring plate198may be formed by a single member made from a ferromagnetic material.

Here, an arrangement for the substrate stage18to chuck the substrate chuck19and an arrangement for the substrate chuck19to chuck the substrate20will be described with reference toFIG. 4. Although a description will be made using the example of the arrangement of the substrate chuck19shown inFIG. 3, the same also applies to the arrangement of the substrate chuck19shown inFIG. 2B. A plurality of support pins41for supporting the substrate20and a sealing bank42that surrounds the plurality of support pins41are arranged on the surface on the side of the mold16of the substrate chuck19. Also, an exhaust hole44connected to an exhaust line43is formed on the surface on the side of the mold16of the substrate chuck19. In a state in which the substrate20is supported by the plurality of support pins41and the sealing bank42, the substrate chuck19can chuck the substrate20by exhausting air from a sealing space between the substrate20and the surface on the side of the mold16of the substrate chuck19via the exhaust line43.

A plurality of support pins45and a sealing bank46that surrounds the plurality of support pins45are arranged on the surface on the side of the substrate stage18of the substrate chuck19. The substrate stage18supports the substrate chuck19via the plurality of support pins45and the sealing bank46. On the other hand, an exhaust hole48connected to an exhaust line47is formed on the substrate stage18. Note that a sealing bank49is arranged around the exhaust line43. In a state in which the substrate chuck19is supported by the plurality of support pins45and the sealing banks46and49, air is exhausted from a sealed space between the substrate stage18and the surface on the side of the substrate stage18of the substrate chuck19via the exhaust line47. This allows the substrate stage18to chuck the substrate chuck19. Accordingly, the substrate chuck19is released from the substrate stage18when the chucking by the substrate stage18is stopped.

As shown inFIG. 5, the imprint apparatus1includes a conveying unit50that holds the surface on the side of the mold16of the substrate chuck19and conveys the substrate chuck19to, for example, replace the substrate chuck19. The conveying unit50includes a movable plate52movable in the X and Z directions, an X driving unit53, and a Z driving unit54. The movable plate52is driven in the X and Y directions by the X driving unit53and the Z driving unit54, respectively. Electromagnets51serving as holding units that generate holding power with respect to the surface on the side of the mold16of the substrate chuck19are arranged in the movable plate52. In this embodiment, three electromagnets51are arranged so as to simultaneously face the magnetic members192placed in the concave portions193of the substrate chuck19, respectively. Each electromagnet51generates electromagnetic power between itself and the magnetic member192. As a result, the conveying unit50can hold the substrate chuck19by a magnetic force via the magnetic member192.

A procedure of conveying the substrate chuck19from the substrate stage18will be described. First, the movable plate52which has been retreated during the imprint process is moved in the X direction, and the movable plate52is positioned so that the electromagnets51will face the magnetic members192. Next, the movable plate52is lowered in the Z direction, and the electromagnets51and the magnetic members192are brought into contact with each other. Electromagnetic power is generated between each electromagnet51and the corresponding magnetic member192by supplying a current to the electromagnet51. When the electromagnets51and the magnetic members192chuck each other (that is, when the substrate chuck19is held), chucking of the substrate chuck19by the substrate stage18is stopped. Subsequently, the movable plate52is moved upward in the X direction, the substrate chuck19is lifted from the substrate stage18, and the movable plate52is moved in the X direction to convey the substrate chuck19to outside of the imprint apparatus1.

In this manner, the conveying unit50approaches the substrate chuck19from above and generates power to hold the substrate chuck19from above. This kind of arrangement eliminates the need to provide a space below the substrate chuck19to insert a robot hand to convey the substrate chuck19. As a result, when the gas22supplied to the imprint space SP flows out, that is, leaks to the space (not shown) below the substrate chuck19, the leak amount can be suppressed.

In this manner, according to the imprint apparatus1of this embodiment, the leak amount of the gas22supplied to the imprint space to the space below the substrate chuck19can be suppressed. Therefore, the imprint apparatus1can maintain a constant gas concentration in the imprint space without changing the flow rate of the gas22supplied from the gas supply unit21.

Note that it is preferable to minimize the gap (channel CH) between the substrate chuck19and the protection plate23as much as possible to minimize the leak amount of the gas22supplied to the imprint space SP. In the same manner, it is preferable to minimize the gap between the magnetic members192and the concave portions193or the ring plate198as much as possible.

The substrate chuck19and the ring plate198(substrate20) are described as having a circular shape in this embodiment. However, the present invention is not limited to this, and their shapes may appropriately be changed in accordance with the shape of the substrate20. For example, the shape of the substrate chuck19and the ring plate198may be a polygon.

A method of manufacturing an article according to an embodiment of the present invention is, for example, suitable for manufacturing an article such as a semiconductor device or liquid crystal display element. The manufacturing method includes a step of forming a pattern on a substrate (a wafer, a glass plate, a film-like substrate, or the like) using the imprint apparatus1and a step of processing the substrate on which the pattern has been formed. The step of processing the substrate can include a step of removing a residual layer of the pattern. Additionally, other known steps such as a step of etching the substrate by using the pattern as a mask can be included. The method of manufacturing an article according to the embodiment is superior to a conventional method in at least one of the performance, quality, productivity, and production cost of the article.

The present invention does not limit the lithography apparatus to the imprint apparatus and is also applicable to the lithography apparatuses such as an exposure apparatus. Note that the exposure apparatus is a lithography apparatus that uses beams such as light and charged particles to expose the substrate via a reticle or a mask and a projection optical system. In this case, the space between the substrate and the mask serving as the original includes the space between the substrate and the final surface on the side of the substrate of the projection optical system.

This application claims the benefit of Japanese Patent Application No. 2016-028298 filed on Feb. 17, 2016, which is hereby incorporated by reference herein in its entirety.