Imprint apparatus, control method, and method for manufacturing article

An imprint apparatus for forming a pattern in an imprint material on a substrate using an original as a mold, comprises an ultraviolet light generation device which irradiates with ultraviolet light which is curing light for curing the imprint material, and a control unit which controls a light amount of the ultraviolet light which is curing light. The control unit configured to perform a control of the light amount of the ultraviolet light acquires data of a defect distribution of the pattern formed on the substrate by the mold, and performs the control of the light amount of the ultraviolet light in a plurality of shot areas on the substrate based on the acquired data of the defect distribution.

BACKGROUND OF THE INVENTION

Field of the Invention

The present invention relates to an imprint apparatus, a control method, and a method for manufacturing an article.

Description of the Related Art

In an imprint technology for manufacturing a semiconductor device or the like, a pattern is formed by contacting a patterned mask onto a silicon substrate to which an imprint material is applied and curing the imprint material using ultraviolet light or heat. In the imprint technology, helium which can be transmitted through the mask and the imprint material is filled into a sealing space to prevent an air reservoir from remaining between the mask and the imprint material, in bringing the mask and the imprint material on the silicon substrate into contact. If a concentration of helium is insufficient, oxygen remains in the sealing space and curing the imprint material is inhibited, and thereby pattern defects occur. Occurrence of the pattern defects due to this curing inhibition may be reduced by increasing an irradiation amount of curing light.

As a technology to give a distribution in a light amount of curing light in an imprint area to reduce pattern defects, Japanese Patent Laid-Open No. 2011-181548 discloses a method of reducing a mold release force by decreasing the light amount of curing light in a center portion in which pattern defects are likely to occur in mold releasing. In Japanese Patent Laid-Open No. 2011-181548, a light amount is adjusted by using a photomask which has a transmittance distribution to decrease the light amount of curing light in the center portion. Japanese Patent Laid-Open No. 2014-120604 discloses a method of reducing the mold release force by weakening the light amount of curing light in an outer peripheral area of a pattern. In Japanese Patent Laid-Open No. 2014-120604, the light amount of curing light is adjusted with a combination of switching of a filter with a transmittance distribution and light-shielding shutter switching time by a light-shielding plate.

However, Japanese Patent Laid-Open No. 2011-181548 and Japanese Patent Laid-Open No. 2014-120604 disclose a technology for reducing pattern defects caused by an adhesion force generated in releasing a mold from a cured imprint material, and the technology cannot be applied to pattern defects caused by curing inhibition due to oxygen that occurs at low concentration of helium. For the pattern defects caused by curing inhibition due to oxygen, it is necessary to irradiate with a light amount of curing light according to a helium concentration distribution or a helium flow rate.

SUMMARY OF THE INVENTION

The present invention provides, for example, an imprint apparatus which is capable of reducing pattern defects formed on a substrate.

According to one aspect of the present invention, an imprint apparatus for forming a pattern of an imprint material on a substrate using a mold is provided that comprises a light source configured to irradiate with curing light for curing the imprint material, and a control unit configured to acquire data of a defect distribution of the pattern formed on the substrate by the mold, and to perform a control of a light amount of the curing light for curing the imprint material in a plurality of shot areas on the substrate based on the acquired data of the defect distribution.

DESCRIPTION OF THE EMBODIMENTS

First Embodiment

An outline of an imprint apparatus according to one embodiment of the present invention will be described with reference toFIG. 1.FIG. 1shows an example of an apparatus configuration of the imprint apparatus. An imprint apparatus100of the present embodiment is configured to form a pattern in a plurality of shot areas on a substrate by repeating an imprint cycle. Here, one imprint cycle is a cycle of forming a pattern in one shot area of the substrate by curing the imprint material, in a state in which an original (mold) contacts with an uncured resin (imprint material).

In a substrate1, an element pattern corresponding to a pattern of an original is formed on a surface layer by transferring the pattern of the original thereto. A substrate fine movement stage2is a stage in which the substrate1can be driven in an XY direction and a rotation direction in an XY plane in little amounts (about 1 mm in the XY direction, about a few degrees in the rotation direction in the XY plane). A substrate rough movement stage3is a substrate stage in which the substrate1can be moved in large amounts in the XY direction, and can move an imprint area from a carry-in/carry-out position of the substrate1toward an entire surface of the substrate in directions orthogonal to each other.

A base frame4of an imprint apparatus holds and positions the substrate fine movement stage2and the substrate rough movement stage3. An original5has a convex-concave pattern engraved on a surface thereof and the engraved pattern is transferred to the substrate1by interposing an imprint material between the original5and the substrate1and transferring the original to the substrate. A driving device5awhich performs a vertical drive of the original performs an operation of bringing the original5an uncured resin on the substrate1into contact. An ultraviolet light generation device6irradiates the uncured resin with ultraviolet light6athrough the original5to cure the resin. In addition, the ultraviolet light generation device6includes, for example, a point light source such as a halogen lamp or a mercury lamp for generating i-rays or g-rays, and has functions of collecting and shaping light generated by the point light source.

A dispenser7can apply a predetermined amount of uncured resin onto the substrate1by discharging fine liquid droplets of uncured resin. A tank8for storing the uncured resin supplies the uncured resin to the dispenser7through a pipe9. A movable device10is a movable unit which moves the dispenser7between a discharge position and a retracted position (maintenance position), and is positioned at a discharge position during a normal discharge operation. During maintenance of the dispenser7, the movable device is moved to the retracted position (maintenance position) and cleaning and replacement of the dispenser7is performed.

An alignment scope11is a microscope which aligns pattern positions of the original5and the substrate1after discharging and applying the uncured resin onto the substrate1using the dispenser7. A mutual alignment is performed by measuring a state in which an alignment mark provided on the original5and an alignment mark on the substrate1are superimposed, using the microscope. A helium nozzle12is a nozzle for blowing helium gas which is a gas for facilitating filling of the imprint material and for preventing curing inhibition by oxygen. In particular, it is not limited to helium gas, and may be a gas having a function similar to helium gas. The tank13is a tank for storing helium gas and supplies helium gas to a nozzle portion through a pipe. A plate14is for supporting and fixing the original5through the helium nozzle12.

A flow of a series of imprinting operations will be described usingFIGS. 2A to 2D and 3A to 3C.FIGS. 2A to 2DandFIGS. 3A to 3Care for explaining an imprint sequence. In a process ofFIG. 2A, the substrate1is mounted on the substrate fine movement stage2and the substrate rough movement stage3. In a process ofFIG. 2B, the substrate1starts to move under the dispenser7for discharging an uncured resin, by using the substrate fine movement stage2and the substrate rough movement stage3. Next, as the process proceeds to that ofFIG. 2C, the dispenser7completes an application of a predetermined amount of uncured resin on to the substrate. Thereafter, as the substrate fine movement stage2and the substrate rough movement stage3return under the original5, helium gas is blown onto the substrate1by using the helium nozzle12and a space for contacting (a space between the mold and the substrate) is filled with helium gas. Then, the process proceeds to that ofFIG. 2D, the alignment scope11superimposes the alignment mark of the original5and the alignment mark on the substrate1by driving the substrate fine movement stage2, and performs relative position adjustment of the substrate1and the original5.

Next, in a process A ofFIG. 3A, the original5is lowered toward the substrate1by using the driving device5a, and a pattern on the original5is brought the uncured resin into contact and transferred to the uncured resin. Then, in the process ofFIG. 3B, the ultraviolet light6ais irradiated from the ultraviolet light generation device6, is transmitted through the original5, and finally irradiates an uncured resin (resist). At this stage, the uncured resin is cured. In a next process ofFIG. 3C, the original5is peeled off and allowed to retreat (released) upward, and thereby a patterned resin layer is formed on the substrate1to end the imprinting operation. By undergoing the above processes, an imprint apparatus for replicating and imprinting the pattern of the original on the substrate performs the imprinting operations.

FIG. 4is for explaining an order of imprint on a wafer. Each of rectangles on the wafer ofFIG. 4shows one shot area. The imprinting operations are performed sequentially from an upper left shot area41in an X direction on the substrate1shown inFIG. 4. If the imprinting operation on a line is completed, the line to be imprinted is shifted one down in a Y direction and the imprinting operations are performed sequentially from a left end of the line in the X direction. That is, the imprinting operations are performed in an order of continuous shot numbers41,42,43,44,45,46,47,48, and49inFIG. 4.

FIG. 5shows a configuration of the imprint apparatus to which the configuration of a first embodiment is added. In the imprint apparatus of the first embodiment, a shutter (light-shielding plate)15, a shutter driving mechanism15a, and a calculator16are added. If the shutter15is disposed in an optical path of the ultraviolet light generation device6, the shutter15shields ultraviolet light. If the shutter15is not disposed in the optical path of the ultraviolet light generation device6, the imprint material is exposed by transmission of ultraviolet light. The shutter driving mechanism15ais connected to the shutter15and the calculator (computer)16. The calculator16is configured to calculate, for example, open/close times (opening and closing (shielding) times) of the shutter for each shot. The calculator16is configured to acquire data of a defect amount (defect distribution) at each imprint position on the substrate1, and calculate and determine a light amount of curing light necessary for curing the imprint material based on the acquired data of the defect distribution. Then, the calculator is configured to calculate the open/close times of the shutter according to each imprint position based on the determined light amount. The shutter driving mechanism15aperforms opening and closing of the shutter according to the open/close times of the shutter sent from the calculator16. Accordingly, the calculator16functions as a control unit for controlling an exposure amount of the ultraviolet light6aand controls an exposure amount for each shot area on the substrate1.

FIG. 6is for explaining a defect distribution of the pattern formed on the substrate of the first embodiment. An example of a defect amount distribution at an imprint position on the substrate1is indicated with a density of a gray color. The defect distribution of the pattern is a result of an inspection obtained by inspecting an imprinted wafer with an inspection device. At a position close to an end portion of the substrate1such as an area17a, a concentration of helium is low and pattern defects due to non-curing caused by an effect of curing inhibition by oxygen are likely to occur. Even in an area17bwhich is a position close to an outer periphery, the helium concentration is low and defects are likely to occur next to the area17a. At a position close to a center position such as an area17c, the concentration of helium is sufficient and defects are less likely to occur. In this manner, the helium concentration distribution depends on a position on the wafer, and thus the defect distribution of the pattern also depends on a position on the wafer.

In an area which is close to the end portion of the substrate1such as the area17aand in which the concentration of helium is low and pattern defects due to non-curing caused by the effect of curing inhibition by oxygen are likely to occur, it is necessary to increase the light amount (exposure amount) of curing light. On the other hand, in an area which is close to a center position of the substrate1such as the area17cand in which the concentration of helium is sufficient and defects are less likely to occur, it is not necessary to increase the exposure amount. The exposure amount can be realized by adjusting a light amount of the ultraviolet light generation device6which is a light source or by adjusting an exposure time, that is, an opening time of the shutter.

As described above, the imprint apparatus of the first embodiment can calculate the exposure amount and the opening time of the shutter according to the defect distribution of the pattern on the substrate1, perform exposure in accordance with the imprint position by driving the shutter based on the result of the calculation, and reduce the pattern defects.

Second Embodiment

FIG. 7shows an example of a configuration of an imprint apparatus of a second embodiment. The imprint apparatus of the present embodiment further comprises a filter18having a transmittance distribution and a filter driving mechanism18ain addition to the shutter15and the calculator16of Embodiment 1. The filter18is configured by a plurality of filters with different transmittance distributions. The calculator16is connected also to the filter driving mechanism18a. The calculator16selects a filter in addition to the open/close times of the shutter in accordance with the amount of necessary curing light calculated based on the acquired data of the defect distribution on the substrate1and also issues a command for filter switching (putting the filter in/out an optical path). The filter driving mechanism18areceives the command for filter switching from the calculator16and can perform filter switching to a filter selected among the plurality of filters with different transmittance distributions.

FIG. 8is for explaining a defect distribution on the substrate of the second embodiment. An example of a defects amount distribution at an imprint position on the substrate1is indicated with a density of a gray color. As shown inFIG. 8, there are different helium concentration distributions even in an imprint area of the same one shot, and thereby there are different defect distributions. If an upper right area is taken as an example, in a position such as an area19aclose to an end portion even in the same imprint area, a concentration of helium is low, defects due to insufficient curing caused by the effect of curing inhibition by oxygen are likely to occur, and a defect density is high. On the other hand, even in the same imprint area, an area19bis positioned closer to a center side than the area19a. However, since the area19bis close to an outer periphery, a concentration of helium is low next to the area19aand defects are likely to occur, but a defect density is lower than that of the area19a. In addition, if immediate left imprint area is taken as an example, since an area19cis close to the outer periphery, a concentration of helium is the same as that of the area19band defects are likely to occur, but a defect density is lower than that of the area19a. At a position close to the center position such as an area19d, a concentration of helium is sufficient and defects are less likely to occur. As described above, there are different helium concentration distributions even in the same imprint area, and thereby there are different defect distributions. On the other hand, like an area19e, there are also areas in which a uniform concentration of helium is maintained and the pattern defect density is same, in the same imprint area. If there is a defect distribution vertically or horizontally in the same imprint area, it is possible to have an exposure amount distribution by putting (switching) a filter with a transmittance distribution in an optical path in the same arrangement. If there is a uniform defect distribution in the same imprint area, there is no filter or there may be switching to a filter with a uniform transmittance distribution.

In this manner, the imprint apparatus of the embodiment in which the filter switching mechanism as a unit configured to have the exposure amount distribution in the imprint area of the same one shot is added can further reduce the pattern defects.

Third Embodiment

FIG. 9shows a configuration example of an imprint apparatus of a third embodiment. The imprint apparatus of the present embodiment comprises a light source lamp20and a lamp position driving mechanism20aas a mechanism for driving a position of a lamp, in addition to the shutter15and the calculator16of the first embodiment. The lamp position driving mechanism20ais connected to the light source lamp20. The lamp position driving mechanism20ais connected to the calculator16, and is a driving unit for driving the light source lamp20based on a lamp position command from the calculator16. The calculator16is a control unit for controlling an exposure amount of the ultraviolet light6a, and controls the lamp position driving mechanism20ain addition to the shutter driving mechanism15a. Therefore, with respect to defect distributions in top, bottom, left, and right as shown inFIG. 8of the second embodiment acquired by the calculator16, it is possible to irradiate with curing light having an exposure amount distribution corresponding to defect distributions by controlling a position of the light source lamp20. It is possible to cause the exposure amount distribution without loss of exposure energy compared to a filter. The filter switching mechanism and the lamp position driving mechanism may be configured to be combined.

As described above, the imprint apparatus of the third embodiment in which the lamp position driving mechanism as a unit configured to have an exposure amount distribution in an imprint area of the same one shot is added, can reduce pattern defects without loss of exposure energy.

Fourth Embodiment

FIG. 10shows an example of a configuration of an imprint apparatus of a fourth embodiment. The imprint apparatus of the present embodiment is configured to use an LED element as a light source of the ultraviolet light generation device6. An LED element group21is disposed inside the ultraviolet light generation device6includes and the LED element group21is connected to an LED power control device21a. The LED power control device21ais connected to the calculator16and is capable of individually changing a power to each of the LED elements based on an exposure amount distribution or an LED power amount distribution calculated based on a defect distribution by the calculator16. The LED element is, for example, an ultraviolet LED.

FIG. 11is for explaining the LED element group21that is a light source element unit of the imprint apparatus of the fourth embodiment.FIG. 11shows the LED element group21viewed in a −Z direction. The LED element group21has a plurality of LED elements, andFIG. 11shows a arrangement of the LED elements on a plane in a direction perpendicular to an irradiation direction of light of the LED element group21. An LED element21bis disposed in an area corresponding to an irradiation area on the substrate1and a configuration of optical elements in an optical path. According to an exposure amount or optical characteristics of one LED element, a density or the number of elements is determined. Moreover, in this embodiment, each LED element is covered with a hemispherical dome lens, but the LED element may be exposed corresponding to an imaging condition of a light source. It is possible to individually control the exposure amount of the LED element21bby the LED power control device21a.

FIG. 12is for explaining a defect distribution on the substrate of Embodiment 4. An example of a defect amount distribution at an imprint position on the substrate1is indicated by a density of a gray color. A concentration of helium is low at a position close to the end portion of the substrate1such as an area22a, and here defects due to a curing shortage caused by the effect of curing inhibition by oxygen is most likely to occur. The area22bis positioned inside of the area22a, and here defects are next most likely to occur. At a position close to a center position, such as an area22c, there are few defects and it is not necessary to increase the exposure amount. In such a defect distribution, there are both a fine area distribution and a fine defect concentration distribution in an imprint area of the same one shot. Therefore, it is necessary to have a fine exposure amount distribution in the same imprint area. By individually controlling an exposure amount of the LED element21bof the LED element group21, it is possible to perform a control on the light amount of curing light and to realize a desired fine exposure amount distribution without using a shutter mechanism, a filter switching mechanism, a lamp position driving mechanism, or the like.

Furthermore, the configuration of the fourth embodiment can also be applied to a case in which an imprint area for performing an imprint at one time is increased by disposing the increased number of LED element groups as shown inFIG. 13.FIG. 13is a diagram in which four of the LED element groups21shown inFIG. 11are aligned. For example, for a configuration in which the imprint area is quadrupled, it is possible to obtain the same effect by aligning the four LED element groups21corresponding the quadrupled imprint area, and individually performing a power control on the LED elements21b. The LED element groups21may be aligned as many as a number corresponding to a size of an imprint area for performing an imprint at one time. Note that a light source may be a LED element group, and a configuration in which the shutter mechanism, the filter switching mechanism, and the lamp position driving mechanism are combined may be provided.

In this manner, the imprint apparatus of the fourth embodiment comprising the LED element group which is the light source as a unit configured to have the exposure amount distribution in the imprint area can generate a the fine exposure amount distribution and further reduce the pattern defects by individually controlling the power of each LED element.

These embodiments are applicable to an imprint method and an imprint apparatus. Specifically, these embodiments are applicable to an imprint method and an imprint apparatus for accurately positioning (alignment) an original such as a template or a reticle and a substrate such as a semiconductor wafer, and transferring a pattern of the original to the substrate.

Embodiment of Article Manufacturing Method

A method for manufacturing a device (semiconductor integrated circuit element, liquid display element, or the like) as an article may include a step of forming a pattern on a substrate (wafer, glass plate, film-like substrate, or the like) using the imprint apparatus described above. Furthermore, the manufacturing method may include a step of etching the substrate on which a pattern has been formed. When other articles such as a patterned medium (storage medium), an optical element, or the like are manufactured, the manufacturing method may include another step of treating (processing) the substrate on which a pattern has been formed instead of the etching step. The article manufacturing method of the present embodiment has an advantage, as compared with a conventional method, in at least one of performance, quality, productivity and production cost of an article.

This application claims the benefit of Japanese Patent Application No. 2016-017114, filed Feb. 1, 2016, which is hereby incorporated by reference wherein in its entirety.