1. Field of the Invention
The present invention relates to an imprint material discharging device that discharges an imprint material.
2. Description of the Related Art
A so-called imprint technique, in which, in a process for manufacturing, for example, a semiconductor device, a mold having a pattern is brought into contact with an imprint material on a substrate and the shape of the mold is transferred to the imprint material to form a pattern thereon, is known. As an imprint material discharging device that discharges an imprint material onto a substrate, a discharging device using an inkjet head is described in Japanese Patent Laid-Open No. 2014-216471.
The inkjet head of the discharging device that is described in Japanese Patent Laid-Open No. 2014-216471 includes energy generating elements that generate energy for discharging the imprint material onto the substrate. In such a discharging device, when foreign substance is contained in the imprint material, a proper pattern may not be formed when the mold is brought into contact with the imprint material. Therefore, in the discharging device that is described in Japanese Patent Laid-Open No. 2014-216471, the imprint material from which the foreign substance has been removed by a filter is supplied to a container section.
According to an aspect of the present invention, an imprint material discharging device that discharges onto a substrate an imprint material on which a pattern is formed by bringing a mold into contact with the imprint material includes a container member that includes a container section that contains the imprint material; a channel that is connected to the container section; and a discharging member that includes a discharge port for discharging the imprint material, an energy generating element that generates energy for discharging the imprint material from the discharge port, and a region that is disposed between the energy generating element and the discharge port. The channel has a first opening and a second opening, the first opening supplying the imprint material contained in the container section into the channel and opening into the container section, the second opening supplying the imprint material supplied from the first opening to the container section and opening into the container section. A filter that filters the imprint material is disposed between the first opening and the second opening of the channel, and the imprint material supplied into the channel from the first opening is supplied to the container section from the second opening without passing through the region.
Further features of the present invention will become apparent from the following description of exemplary embodiments with reference to the attached drawings.
Studies conducted by the inventor et al. have revealed that discharging devices such as that described in Japanese Patent Laid-Open No. 2014-216471 have the following problems. For example, when an imprint material or an imprint material container section in which the imprint material is contained is left unattended for a long period of time, a portion of the imprint material may change with time and become gelated in the imprint material container section. In addition, the imprint material may become contaminated by foreign substance that is produced in the container section. When, in such a state, the imprint material is discharged onto a substrate, a mold with which the imprint material is brought in to contact may become damaged, and the patterning precision of the imprint material may be reduced.
According to the method that is described in Japanese Patent Laid-Open No. 2014-216471, since the imprint material passes through the filter before entering the container section, the foreign substance or the like has been removed when the imprint material enters the container section. However, as described above, it is difficult to handle foreign substance that is produced in the container section and to deal with changes in the imprint material with time.
According to the studies conducted by the inventor et al., the size of any foreign substance that is produced in the imprint material container section as mentioned above is approximately a few tens of nm, which is small. When an imprint material channel is disposed in a filter having a small opening diameter that allows such foreign substance to be removed, the channel resistance (pressure loss) in the filter may slow down the supply of the imprint material to a discharging member, or may influence the discharge of the imprint material.
Therefore, the present invention provides an imprint material discharging device that is capable of properly discharging an imprint material from a discharging member while properly removing any foreign substance that is produced in the imprint material in a container section by using a filter.
An embodiment of the present invention is hereunder described with reference to the drawings.
The imprint apparatus 100 shown in
The imprint material discharging device 10 includes an imprint material discharging member 11, a container member 12 including a container section 15 for containing the imprint material, and a pressure control member 13. A substrate 4 is provided on a stage 6. An imprint material 8 is discharged onto the substrate 4 from the discharging member 11. The mold 1 is brought into contact with the imprint material 8 that has been discharged onto the substrate. In this state, the imprint material 8 is irradiated with ultraviolet light emitted from an ultraviolet light irradiation device 7, and is cured. A fine irregular pattern or the like is formed in the mold 1. When the mold 1 is moved upward, the imprint material is in a state in which the pattern of the mold has been transferred to the imprint material. In this way, the pattern is formed on the imprint material.
The stage 6 is movable along a base frame 5 while the stage 6 holds the substrate 4. A mold driving mechanism 2 that vertically drives the mold 1 is held by a structure 3. The mold driving mechanism 2 is capable of bringing the mold 1 towards the substrate 4, and bringing the mold 1 into contact with the imprint material 8. The ultraviolet light irradiation device 7 exists above the mold 1, and irradiates the imprint material 8 with ultraviolet light 9 via the mold 1. The ultraviolet light 9 may be generated from, for example, a light source such as a halogen lamp that generates an i-line and a g-line. The ultraviolet light irradiation device 7 may have a function of condensing light generated from the light source.
An imprint operation using the imprint apparatus 100 is described in detail. First, the substrate 4 is placed on the stage 6. The stage 6 moves the substrate 4 to a location that is underneath the discharging member 11 of the imprint material discharging device 10. While moving the stage 6, the imprint material 8 is discharged onto the substrate 4 from the discharging member 11.
Next, the stage 6 moves a portion of the substrate 4 onto which the imprint material 8 has been discharged to a location that is underneath the mold 1. Further, the mold driving mechanism 2 lowers the mold 1, and brings the mold 1 close to the substrate 4. In this state, an alignment scope or the like causes an alignment mark on the mold 1 and an alignment mark on the substrate to overlap, so that the position of the mold 1 and the position of the substrate 4 are aligned relative to each other.
After aligning the positions relative to each other, the mold driving mechanism 2 moves the mold 1 further downward (in the direction of the substrate 4), and causes the mold 1 to contact the imprint material 8. Thereafter, the ultraviolet light irradiation device 7 emits the ultraviolet light 9, and applies the ultraviolet light 9 transmitted through the mold 1 to the imprint material 8. As a result, a photo-curing reaction occurs in the imprint material 8, so that the imprint material 8 is cured.
Finally, the mold driving mechanism 2 separates the mold 1 from the cured imprinted material 8. By performing the above-described steps, it is possible to form a pattern on the substrate 4 (that is, a patterned imprint material). The imprint apparatus that is used in manufacturing a semiconductor may be used to form a pattern over the entire region of the substrate 4. In such a case, the imprint operation is repeated with respect to the substrate while changing the regions of the substrate on which the imprint operation is performed.
Next, the imprint material discharging device is described.
The discharging member 12 includes the container section 15 that contains the imprint material, and a filling liquid section 16 that is a space provided opposite to the container section 15 with the separation membrane 14 disposed therebetween and that is not connected to the discharging member 11. The filling liquid section 16 is filled with the filling liquid, and communicates with the pressure control member 13 via a communication portion 17. The pressure control member 13 includes, for example, a filling liquid tank, a pipe, a pressure sensor, a pump, and a valve. The pressure sensor, the pump, and the valve are used to control the pressure of the filling liquid in the filling liquid section. By controlling the pressure of the filling liquid by the pressure control member 13, it is possible to control the pressure of the imprint material in the container section 15 through the separation membrane 14. This makes it possible to stabilize the shape of a gas-liquid interface (meniscus) in the discharging member 11, and to discharge the imprint material with good reproducibility.
When the discharge of the imprint material 8 from the discharging member 11 is repeated, the imprint material in the container section 15 is consumed and is reduced in amount, so that the separation membrane 14 is deformed. As the separation membrane 14 is deformed, the filling liquid section 16 is replenished with filling liquid from the filling liquid tank by the pressure control member 13, so that the filling liquid section 16 is filled with the filling liquid.
The imprint material that is used in the imprint apparatus is required to maintain its properties until the imprint material is applied to the substrate with the amount of foreign substance (number of minute particles) and the number of metallic ions being minimized. In the present invention, until all of the imprint material is finally consumed as a result of the volume of the container section 15 being reduced due to repeated discharge of the imprint material, it is possible to store the imprint material while the imprint material is separated from the outside of the container section 15. Therefore, since the imprint material does not contact outside air and equipment such as the pressure sensor, it is possible to suppress the increase of foreign substances and metallic ions that have been initially controlled and sealed in.
In the container section 15, as the separation membrane, a bag-like flexible membrane, which is like an infusion bag, may be used. A gas-liquid interface may be formed in the container section 15. Alternatively, the container section 15 may be formed into a nonpressure type by connecting an air communication port to the container section 15. When the container section 15 is formed into a nonpressure type, in order to perform proper negative pressure control, it is desirable that the container section 15 be connected to an on-off valve or a device that controls the pressure.
In the field of inkjet recording devices, in order to stabilize the shape of the meniscus at the discharge port of the discharging member, the discharging member is designed such that the interior of the discharging member is maintained at a negative pressure in a certain range. For example, a method for generating negative pressure by utilizing capillary force in the interior of a porous material that is provided in the container section to retain a liquid is known. Other methods include a method for generating negative pressure in the container section by combining a mechanical element, such as a spring, and a balloon-like membrane, and a method for controlling negative pressure by utilizing a control valve and air pressure. Even in the present invention, the negative pressure in the container section may be controlled by such methods.
The imprint material discharging device according to the present invention has a structure in which a channel connected to the container section is provided outside the container member, and in which a filter is disposed in the channel.
When the pump 22 is driven, the imprint material contained in the container section 15 is supplied (sucked) from the first opening 20. After the imprint material supplied from the first opening 20 has passed through and has been filtered by the filter 23 in the channel, the imprint material flows back into the container section 15 through the second opening 21. Then, the imprint material is supplied again from the first opening 20. That is, the imprint material in the container section 15 is circulated and filtered in the filter 23.
In this way, in the present invention, the filter 23 is disposed in the channel that communicates with the container section of the container member instead at a location between the discharging member and the container section of the container member. The imprint material supplied from the first opening 20 of the channel is supplied from the second opening 21 without passing through the region 33 between the discharge port and each energy generating element of the discharging member 11. The channel of the channel formation member 28 is provided at a portion that differs from the region 33 between the discharge port and each energy generating element. By virtue of such a structure, the ink print material is properly supplied to the discharging member 11, and is properly discharged from the discharge port 32 of the discharging member 11. An example of a structure in which the imprint material is circulated and filtered without passing through the region 33 consists in not disposing the region 33 on a straight line that connects the first opening 20 and the second opening 21 to each other.
An imprint material discharging device shown in
In the present invention, it is desirable not to provide the filter between the container section 15 of the container member and the discharging member 11. Even if the filter is provided, the filter is required not to largely influence the supply of imprint material to the discharging member 11. The filter is at least required to be a filter having a channel resistance (pressure loss) that is less than that of the filter 23 in the channel, that is, is required to be a filter having an average aperture that is larger than that of the filter 23 in the channel.
The imprint material discharging device may be in the form of a cartridge that is removable from the imprint apparatus. For example, it is possible to set a state in which imprint can be immediately performed by mounting the imprint material discharging device having the form of a cartridge on the imprint apparatus and replacing the imprint material discharging device having the form of a cartridge after the imprint material in the container section 15 has been completely consumed. It is possible to integrate the pump 22 and the filter 23 with the imprint material discharging device as a cartridge, and replace them at the same time when replacing the imprint material discharging device. Such methods allow the imprint material discharging device to be replaced while minimizing the possibility of foreign substances mixing in the imprint material discharging device. Of the imprint material discharging device, only the container section 15 may be replaceable. That is, with the container section 15 being separable from the pump 22 and the filter 23, it is possible to replace only the container section 15. Since, for example, the pump 22 and the filter 23 are not replaced, this method is desirable from the viewpoint of costs.
The channel formation member 28 shown in
A material having high viscosity may be selected as the imprint material that is used in imprint techniques. In particular, if the discharging device has the form of a cartridge, it is desirable that the pump be small. Therefore, it is desirable that a structure be designed for efficiently filtering the imprint material by the filter 23. Consequently, openings of the channel are provided at the positions shown in
If a material (liquid) having high viscosity has, in particular, low inertial force when it flows, the material flows in a state in which its laminar flow is maintained without being agitated. Therefore, as in the flow denoted by arrows in
The first opening 20 and the second opening 21 may be disposed as shown in
By, as shown in
In order to increase the efficiency with which the imprint material is replaced, as mentioned up until now, it is desirable to circulate and discharge the imprint material. More specifically, as shown in
In order to discharge the imprint material described above, for example, as shown in
Instead of discharging the imprint material in the container section 15 by the pressure control member 13, as shown in
Instead of discharging the imprint material by the pressure controlling member 13 or the suction controlling member 34, it is possible to discharge the imprint material from the discharge port 32 by using the energy generating elements 29 of the discharging member 11. That is, by generating energy from the energy generating elements 29, it is possible to discharge the imprint material in the region 33 and replace the imprint material in the region 33 and the container section 15.
It is possible to set various discharge timings in accordance with the discharge states. The imprint material may be discharged at the same time that the imprint material is circulated and filtered, or the imprint material may be circulated and filtered and discharged after the imprint material has been circulated and filtered for a specified period of time. Alternatively, the imprint material may be circulated and filtered after previously discharging the amount of imprint material required to replace the imprint material that exists in the region 33.
When bubbles exist in a liquid discharge port, since the bubbles may cause the imprint material to be unstably discharged, a removing operation may be performed for removing the bubbles in the discharge port. In order to use the imprint material with good efficiency, the imprint material may be circulated and filtered during the removing operation for removing the bubbles. This makes it possible to efficiently replace the imprint material at the region 33 with the filtered imprint material that has been filtered, and to stably discharge imprint material having a small amount of foreign substance and a small number of metallic ions to the substrate.
Air may exist in the container section 15. For example, as shown in
Due to buoyancy, the air (bubbles) in the imprint material moves towards the top surface, that is, upward in the gravitational direction in the container section 15. Therefore, as shown in
As in the trap space 26, an air-liquid interface exists in the container section 15. When the air-liquid interface exists close to the second opening 21, the imprint material may bubble or air may mix in the imprint material. Therefore, it is desirable that the second opening 21 open at a location below the top surface of the container section 15 in the gravitational direction and below the air-liquid interface in the gravitational direction to supply the imprint material to the container section 15. Therefore, the second opening 21 may have a protruding shape that protrudes from the top surface of the container section 15, or a tube may be connected to the second opening 21 to guide an end of the tube to a location below the air-liquid interface.
A channel may be formed through the discharging member 11. Such a structure is shown in
In the form shown in
An example in which the imprint material supplied into the channel from the first opening 20 is supplied to the container section from the second opening 21 through the region 33 is shown in
Next, a method for initially filling the container section 15 of the imprint material discharging device with the imprint material is described. As shown in
The container section may be filled with the imprint material not only at the initial stage but also during use of the imprint apparatus. For example, while filling the container section 15 with the imprint material from the filling port 27, the imprint apparatus may be used.
From the viewpoint of the structure of the filter 23, air tends to remain in the interior of the filter 23. By filling the filter 23 with the imprint material upward in the gravitational direction, it is possible to reduce the amount of air that remains therein. For example, as shown in
When the filter 23 is a filter having an average aperture that is too large, it becomes difficult to sufficiently remove foreign substance in the imprint material. Therefore, the filter 23 is, desirably, a filter having an average aperture that is less than or equal to 10 nm, and, more desirably, a filter having an average aperture that is less than or equal to 5 nm. In contrast, when the filter 23 is a filter having an average aperture that is too small, it becomes difficult to circulate the imprint material in the channel due to pressure loss at the filter. Therefore, it is desirable that the filter 23 be a filter having an average aperture that is greater than or equal to 2 nm.
When the amount of foreign substance that exists in the imprint material is large, the filter may be clogged for a short period of time. Therefore, it is also desirable for the filter 23 to have a multiple filter structure in which, as a pre-filter, a filter that removes a large foreign substance is disposed on the upstream side in the direction of circulation, and a filter that removes a small foreign substance on the downstream side in the direction of circulation. The filter that removes a large foreign substance is, for example, a filter having an average aperture in the range of 50 nm to 200 nm. The filter that removes a small foreign substance is, for example, a filter having an average aperture in the range of 2 nm to 10 nm.
It is desirable that the filter 23 be of a membrane type or a hollow fiber membrane type. Such filters each include a plurality of fine holes in a membrane by which foreign substances are filtered and do not allow foreign substances having sizes that are greater than or equal to the aperture to pass therethrough. Examples of materials of which the filter is made include polyethylene, fluororesin, and nylon. The amount of metal that exists in the imprint material is required to be very small. Therefore, it is desirable to use a filter that absorbs the metal and that performs ion exchange. It is desirable that a plurality of such filters be disposed in series or in parallel.
As the pump 22, for example, a diaphragm pump, a syringe pump, a tube pump, or a gear pump may be used. It is desirable that the feeding flow rate of the pump 22 be less than or equal to 100 mL/min. When the flow rate is increased, the channel resistance (pressure loss) for passing the imprint material through the filter is increased. Therefore, the pump needs to be a high-output pump. Therefore, by using a pump having a feeding flow rate that is less than or equal to 20 mL/min, it is possible to reduce the size of the pump.
When pressure variations (pulsations) of the imprint material are large due to the driving of the pump, the imprint material tends to leak from the discharging member. Therefore, it is desirable to suppress the pressure variations to an amount that does not allow a meniscus at the discharge port to be broken. For example, it is desirable that the pump be driven such that the pressure variations are within ±300 Pa.
In order to operate the pump 22, the imprint material discharging device includes a controller. Since control is performed such that a certain flow rate is maintained to feed a liquid, when the filter 23 is clogged and the channel resistance is increased, driving voltage is increased. Therefore, when, at the controller, the driving voltage of the pump is monitored at all times, and the driving voltage exceeds a certain value, a warning that urges a user to replace the filter can be issued to the imprint apparatus. When the filter 23 is integrated into the imprint material discharging device having the form of a cartridge, the user can immediately use the imprint apparatus by replacing the imprint material discharging device. In order to detect any abnormality in the pump 22 and the filter 23, a sensor that monitors the states thereof may be provided, or, for example, a pressure sensor or a flow rate sensor may be formed in a pipe.
The imprint material discharging device is required to discharge very precise amounts of imprint material onto very precise landing locations on the substrate. Therefore, the shape of the meniscus at the discharge port of the discharging member needs to be stably maintained. In the imprint material discharging device, the pressure of the imprint material may vary as a result of the driving of the pump 22. Therefore, it is desirable that the driving of the pump 22 be stopped while the imprint material is being discharged from the imprint material discharging device.
In the imprint step, a pattern is formed on each region on the substrate while the discharge of the imprint material onto the substrate, the contacting of the mold from the imprint material, exposure, and the separation of the mold are repeated. Therefore, it is desirable that the imprint material be circulated and filtered at the container section 15 at a timing other than when the imprint material is being discharged onto the substrate. The timing at which the imprint material is circulated and filtered may be a timing at which the substrate or a lot is replaced.
The imprint material may be circulated and filtered when the amount of foreign substances, such as particles and gels, is increased in the container section 15. Therefore, the imprint material may be circulated and filtered when the apparatus is not operating. It is possible to stop the pump 22 when the imprint step is being executed, and circulate and filter the imprint material during maintenance of the apparatus or during a period of time in which a substrate on which an imprint operation is to be performed does not exist. It is possible to provide the imprint apparatus or the discharging device with a timer function, and circulate and filter the imprint material when a certain time has elapsed. It is also possible to control the pump 22 on the basis of a programmed instruction from the imprint apparatus or the discharging device, or perform a method in which the pump 22 is driven by a user.
When the imprint material is circulated and filtered by causing the moving mechanism 30 to move the container member 12 to the location where maintenance is performed, even if the imprint material has leaked from the discharging member 11 due to large pressure variations, the imprint material can be received by the receiving pan 31. This is effective, for example, when one wants to return the process to the imprint step by quickly ending the circulation and filtering of the imprint material as a result of increasing the circulation and filtering flow rate by increasing the output of the pump 22.
The timing at which the imprint material is circulated and filtered may be determined in accordance with, for example, the time that has elapsed from the start of use of the imprint material discharging device of the imprint apparatus, the amount of use of the imprint material, the time that has elapsed from the previous circulation and filtering of the imprint material, and the storage environment history of the imprint material discharging device. Since the degree of gelation depends upon the environment and the type of imprint material, the degree of gelation may be determined on the basis of the type of imprint material.
When the remaining amount of imprint material decreases, the amount of imprint material that is circulated and filtered may be reduced, or conditions, such as the circulation and filtering timing and the flow rate, may be changed in accordance with the remaining amount of imprint material in the container section.
The pump 22 may be intermittently operated. When the pump 22 is controlled and driven at all times at a low flow rate, it is possible to suppress pressure variations. When a diaphragm pump is used as the pump 22, it is possible to, by reducing the vibration width of the diaphragm, suppress pressure variations and circulate and filter the imprint material at all times.
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. 2015-076992, filed Apr. 3, 2015, and Japanese Patent Application No. 2016-002753, filed Jan. 8, 2016, which are hereby incorporated by reference herein in their entirety.
Number | Date | Country | Kind |
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2015-076992 | Apr 2015 | JP | national |
2016-002753 | Jan 2016 | JP | national |