JP6250022B2 - Imprint apparatus, article manufacturing method, and imprint method - Google Patents

Description

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

  The demand for miniaturization of semiconductor devices has advanced, and microfabrication technology for forming an uncured resin on a substrate with a mold and forming a resin pattern on the substrate has attracted attention. Such a technique is also called an imprint technique, and can form a fine structure on the order of nanometers on a substrate. For example, in an imprint apparatus that employs a photocuring method as a resin curing method, an ultraviolet curable resin (imprint material) is applied to a shot area (imprint area) on a substrate, and the resin (uncured resin) is applied. ) With a mold. Then, after the resin is cured by irradiating with ultraviolet rays, the mold is peeled off (released) to form a resin pattern on the substrate.

  In the imprint apparatus, since the atmosphere in the apparatus is generally air, when the mold and the resin are pressed against each other, the air stays between them, and bubbles may be mixed into the resin as residual gas. In such a case, there is a possibility that a defect is generated in the pattern transferred onto the substrate and an accurate pattern cannot be formed on the substrate. On the other hand, it is conceivable to wait until the residual gas dissolves, diffuses or permeates in the resin or mold and disappears, but the imprint process takes a long time.

  Therefore, an imprint apparatus has been proposed in which a permeable gas is used in an imprint atmosphere and the permeable gas remaining in a resin or a mold is dissolved or diffused to quickly reduce the residual gas (see Patent Document 1). ). In addition, an imprint apparatus has also been proposed that uses a condensable gas that condenses due to an increase in pressure when the mold and the resin are pressed against the imprint atmosphere (see Patent Document 2). The condensable gas is liquefied when it remains, and its volume is reduced to one hundredth compared to when it is gas, so that the influence of the residual gas on pattern formation can be suppressed. In addition, when condensable gas is used, the viscosity of the resin decreases due to absorption of the liquefied condensable gas into the resin, so the spreading speed of the resin on the substrate increases, and the pattern can be obtained in a shorter time. Can be formed.

  On the other hand, when a permeable gas or a condensable gas enters an optical path such as an interferometer that measures the position of the substrate stage, the interferometer cannot accurately measure the position of the substrate stage. Therefore, use a mixed gas of permeable gas and condensable gas in the imprint atmosphere to reduce the measurement error of the interferometer (so that the refractive index is the same as the refractive index of the atmosphere). A technique for adjusting the mixing ratio of gas and condensable gas has also been proposed (see Patent Document 3).

US Pat. No. 7,090,716 Japanese Patent No. 3700001 JP 2012-164785 A

  However, in pattern formation by an impregnation process in a condensable gas atmosphere, the liquefied condensable gas absorbed by the resin is released to the outside after mold release, which may degrade the shape of the pattern formed on the substrate. There is sex. For example, the roughness of the surface of the pattern increases, the density of the resin decreases, the line width of the pattern decreases, and the cross-sectional shape of the pattern tends to deteriorate. Such a tendency is stronger as the concentration of the condensable gas is higher. On the other hand, the higher the concentration of the condensable gas, the shorter the pattern formation time. Thus, there is a trade-off between accurate pattern formation and improvement in throughput (productivity).

  An object of the present invention is to provide an imprint apparatus that is advantageous in achieving both accurate pattern formation and throughput.

In order to achieve the above object, an imprint apparatus according to one aspect of the present invention is an imprint apparatus that forms a pattern on the substrate by performing a mold on an imprint material on the substrate, and is used for the mold. Information on the characteristics of the pattern formed on the substrate, which differs depending on the supply section for supplying a condensable gas that can be liquefied by the pressing mold into the space between the mold and the substrate, and the line width of the pattern to be formed based on the relationship between the concentration of the condensable gas in the space between, and having a control unit for controlling the concentration of the condensable gas, the space supplied Ri by the said supply unit .

  Further objects and other aspects of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  According to the present invention, for example, it is possible to provide an imprint apparatus that is advantageous for achieving both accurate pattern formation and throughput.

It is the schematic which shows the structure of the imprint apparatus as 1 side surface of this invention. It is a figure which shows the relationship between the density | concentration of the condensable gas in the mixed gas of permeable gas and condensable gas, and the shrinkage | contraction rate of a pattern.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. In addition, in each figure, the same reference number is attached | subjected about the same member and the overlapping description is abbreviate | omitted.

  FIG. 1 is a schematic diagram showing a configuration of an imprint apparatus 1 as one aspect of the present invention. The imprint apparatus 1 is used for manufacturing a device such as a semiconductor device, and an imprint material (resin) on a substrate is molded with a mold and cured to form a pattern (resin pattern) on the substrate. An apparatus that performs imprint processing. Here, the imprint apparatus 1 employs a photocuring method as a resin curing method. The imprint apparatus 1 includes an illumination system 2, a mold holding unit 3, a substrate stage 4, a resin supply unit 5, a gas supply unit 6, a control unit 7, and a measurement unit 15. Further, as shown in FIG. 1, the direction parallel to the optical axis of the illumination system 2 that irradiates the resin on the substrate with ultraviolet rays is defined as the Z axis, and the directions perpendicular to each other in a plane perpendicular to the Z axis are defined as the X axis. And Y axis.

  The illumination system 2 irradiates the mold 8 with ultraviolet rays during the implementation process. The illumination system 2 includes an optical element for adjusting the ultraviolet light emitted from the light source to light suitable for imprinting. The mold 8 is a mold in which a predetermined pattern (for example, a concavo-convex pattern corresponding to a pattern to be formed on the substrate 10) is three-dimensionally formed on the surface facing the substrate 10. The mold 8 is made of a material (such as quartz) that can transmit ultraviolet rays. Further, an alignment mark detection system (not shown) is arranged adjacent to the illumination system 2 or included in the illumination system 2, and the alignment mark formed on the substrate 10 in the previous process and the alignment mark of the mold 8 are arranged. Align with.

  The mold holding unit 3 holds the mold 8 by a vacuum suction force or an electrostatic force. The mold holding unit 3 includes a mold chuck 9 and a mold moving mechanism (not shown) that moves the mold 8 in the Z-axis direction. The mold moving mechanism realizes a pressing operation for pressing the mold 8 against uncured resin on the substrate 10 and a releasing operation for pulling the mold 8 away from the cured resin on the substrate 10. Thus, in this embodiment, the pressing operation and the releasing operation in the imprint apparatus 1 are realized by moving the mold 8 in the Z-axis direction. However, the pressing operation and the releasing operation may be realized by moving the substrate 10 (substrate stage 4) in the Z-axis direction, or the pressing operation is performed by moving both the mold 8 and the substrate 10 in the Z-axis direction. In addition, the releasing operation may be realized.

  The substrate stage 4 includes, for example, a substrate chuck 11 that holds the substrate 10 by vacuum suction and is movable in the XY plane. The substrate 10 is a substrate made of single crystal silicon, for example. A resin molded by the mold 8 is applied (supplied) to the surface of the substrate 10. The substrate stage 4 is provided with a plurality of reference mirrors (reflection surfaces) 13 for controlling the positions of six degrees of freedom (X, Y, Z, ωx, ωy, ωz). The imprint apparatus 1 includes a plurality of laser interferometers 14 that measure the position of the substrate stage 4 by irradiating each of the reference mirrors 13 with light. The laser interferometer 14 measures the position of the substrate stage 4 in real time, and the control unit 7 performs positioning control of the substrate 10 (substrate stage 4) based on the measurement value of the laser interferometer 14.

  The resin supply unit 5 supplies uncured resin 12 on the substrate 10. The resin 12 is an ultraviolet curable resin having a property of being cured by receiving ultraviolet light, and is appropriately selected according to a semiconductor device manufacturing process and the like.

  The gas supply unit 6 is permeable to the pressing position, that is, the space between the resin on the substrate 10 and the mold 8 during the pressing operation of pressing the mold 8 against the uncured resin on the substrate 10. A mixed gas in which a gas and a condensable gas are mixed is supplied. The gas supply unit 6 is a permeable gas having a property of dissolving or diffusing with respect to at least one of the mold 8, the resin 12, and the substrate 10. In this embodiment, the gas supply unit 6 permeates the mold 8 during the molding of the resin 12 by the mold 8. A permeable gas supply unit 20 that supplies a permeable gas that can be used is included. The gas supply unit 6 includes a condensable gas supply unit 21 that supplies a condensable gas having a property of condensing and liquefying when pressure is applied when the resin 12 is molded (pressure increase).

  The permeable gas supply unit 20 supplies a gas such as helium or hydrogen as the permeable gas. However, when flammable hydrogen is used as the permeable gas, it is necessary to separately install an explosion-proof system inside the imprint apparatus 1 so as to be careful of fire.

  The condensable gas supply unit 21 supplies HFC (hydrofluorocarbon) typified by, for example, HFC-245fa (1, 1, 1, 3, 3 pentafluoropropane, CHF2CH2CF3) as the condensable gas. Further, the condensable gas supply unit 21 may supply HFE (hydrofluoroether) typified by HFE-245mc (CF3CF2OCH3) as the condensable gas.

  The gas supply unit 6 includes a gas mixing unit 22 that mixes the permeable gas and the condensable gas supplied from the permeable gas supply unit 20 and the condensable gas supply unit 21, respectively. The gas supply unit 6 includes a gas supply control unit 25 that controls the supply amounts of the permeable gas and the condensable gas supplied to the gas mixing unit 22 by the first valve 23 and the second valve 24, respectively. The gas supply control unit 25 mixes each gas at a predetermined component ratio in the gas mixing unit 22, and adjusts the supply amount of the mixed gas by the third valve 26, via the gas supply nozzle 27, and the substrate 10. Control to supply to the space between the resin and the mold 8 is performed. The gas supply control unit 25 may be installed alone in the apparatus and connected to the control unit 7 via a line, or may be configured integrally with the control unit 7.

  The control unit 7 includes a CPU, a memory, and the like, and controls the entire imprint apparatus 1 (operation). The control unit 7 includes a pressing operation and a releasing operation, and controls an imprint process for forming a pattern on the substrate 10. In addition, the control unit 7 controls the gas supply unit 6 so that the mixing ratio of the permeable gas and the condensable gas in the mixed gas is changed. For example, the control unit 7 determines the mixing ratio of the permeable gas and the condensable gas in the mixed gas supplied by the gas supply unit 6 when performing the imprint process. The control unit 7 may be configured integrally with other parts of the imprint apparatus 1, or may be configured separately (at a place) from other parts of the imprint apparatus 1.

  The measurement unit 15 measures a pattern formed by molding and curing the resin 12 with the mold 8 and acquires information on the characteristics (dimensions and shape) of the pattern. The information related to the pattern features includes at least one of the line width, shrinkage rate, cross-sectional shape, height, and surface roughness of the pattern. The measurement unit 15 may be included in the illumination system 2 or may be configured with an off-axis alignment detection system. The measurement unit 15 may acquire information on the features of the pattern by detecting an image of the pattern formed on the substrate 10, or may detect the pattern by detecting the intensity of scattered light incident on the pattern. You may acquire the information regarding the characteristic of. The measurement unit 15 may be installed outside the imprint apparatus 1 as a scanning electron microscope (SEM) or an atomic force microscope (AFM).

  An imprint process in the imprint apparatus 1 will be described. The imprint process is performed by the control unit 7 controlling the respective units of the imprint apparatus 1 in an integrated manner. First, the substrate 10 transported by the substrate transport system is held on the substrate stage 4, and the substrate stage 4 is moved to the supply position of the resin supply unit 5. Then, the resin supply unit 5 supplies the resin 12 to a predetermined shot area (imprint area) of the substrate 10. Next, the substrate stage 4 is moved so that the shot region on the substrate 10 to which the resin 12 is supplied is positioned immediately below the mold 8. Next, alignment of the mold 8 and the substrate 10 (on the upper shot region) and magnification correction of the mold 8 by the magnification correction mechanism are performed, and the mold 8 is moved by the mold moving mechanism to form the resin 12 on the substrate 10. Press the mold 8. By pressing the mold 8 against the resin 12 on the substrate 10, the resin 12 fills the pattern (concave portion) of the mold 8. In this state, the illumination system 2 irradiates ultraviolet rays from the back surface (upper surface) of the mold 8, and the resin 12 is cured by the ultraviolet rays transmitted through the mold 8. Then, after the resin 12 is cured, the mold 8 is moved by the mold moving mechanism to separate the mold 8 from the cured resin 12 on the substrate 10. As a result, a pattern of the resin 12 having a three-dimensional shape corresponding to the pattern of the mold 8 is formed in the shot region on the substrate 10.

  When performing the imprint process of this embodiment, the gas supply unit 6 supplies a mixed gas in which a permeable gas and a condensable gas are mixed into the space between the resin 12 on the substrate 10 and the mold 8. Is done. At this time, the control unit 7, for example, based on the information on the characteristics of the pattern acquired by the measurement unit 15 (hereinafter referred to as “pattern shape evaluation value”), the permeable gas and the condensable gas in the mixed gas, Determine the optimal mixing ratio. Therefore, a mixed gas having a mixing ratio determined by the control unit 7 is supplied to the space between the resin 12 on the substrate 10 and the mold 8 via the gas supply unit 6. For example, the pattern shape evaluation value needs to be acquired in advance by the measurement unit 15 before a pattern formed in the previous shot area is formed in the next shot area. The optimum mixing ratio in the mixed gas is based on a table or an expression representing the relationship between the pattern shape evaluation value and the mixing ratio (for example, the concentration of condensable gas), and the accuracy of the pattern formed on the substrate 10 is acceptable. What is necessary is just to determine so that it may be settled in the range. It should be noted that information such as a table or a formula representing the relationship between the pattern shape evaluation value and the mixture ratio is stored in advance in a memory of the control unit 7 or the like. In addition, pattern shape evaluation values and mixture ratios in a plurality of shot areas in which a pattern is formed before the shot area in which the pattern is formed are stored and estimated based on an average value or a statistical method The optimum mixing ratio may be determined by calculating the value. In addition, the estimated value with higher accuracy is calculated by using the pattern shape evaluation value of the pattern formed not only on the shot area on the same substrate but also on the shot areas on the multiple substrates that have already undergone imprint processing. can do. Also, a test substrate is prepared instead of the substrate 10, the resin 12 is supplied onto the test substrate, the resin 12 on the test substrate is molded by the mold 8 and cured to form a pattern, and the pattern is formed. The pattern shape evaluation value may be acquired by measurement by the measurement unit 15.

  2 (a) and 2 (b) show the results of experimentally determining the relationship between the concentration of the condensable gas in the mixed gas of the permeable gas (helium gas) and the condensable gas and the pattern shrinkage rate. FIG. FIG. 2A shows the relationship between the concentration of the condensable gas and the pattern shrinkage rate for each of the two types of resins A and B. FIG. FIG. 2B shows the relationship between the concentration of the condensable gas and the shrinkage ratio of the pattern for each of different line widths (100 nm and 20 nm) in the same resin. Referring to FIGS. 2A and 2B, as the concentration of the condensable gas in the mixed gas increases, the contraction rate of the pattern increases proportionally. However, the difference in the type of resin and the line width of the pattern It can be seen that the relationship between the concentration of the condensable gas and the shrinkage rate of the pattern is different due to the difference. Therefore, for each type of resin 12 or for each line width of the pattern to be formed on the substrate 10, information such as a table or a formula representing the relationship between the concentration of the condensable gas and the pattern shrinkage rate is stored. Good. Then, the control unit 7 uses, for example, a table or formula as shown in FIG. 2A or 2B, for example, a contraction rate of a pattern formed on the substrate 10 (a contraction rate with respect to the pattern of the mold 8). Is determined to be within an allowable range. As a result, the accuracy of the pattern formed on the substrate 10 can be within an allowable range. Moreover, the control part 7 is good to determine the mixing ratio in a mixed gas so that the density | concentration of the condensable gas in a mixed gas may become the maximum. Thereby, since the amount of the liquefied condensable gas absorbed by the resin 12 (that is, the decrease in the clay of the resin 12) can be maximized, the spreading speed of the resin 12 on the substrate 10 is increased, A pattern can be formed in a shorter time.

  As described above, the imprint apparatus 1 according to this embodiment determines accurate pattern formation and throughput by determining the mixture ratio in the mixed gas based on the pattern shape evaluation value of the pattern formed on the substrate 10 or the test substrate. Can be made compatible.

  Further, instead of the actually formed pattern, permeation in the mixed gas supplied by the gas supply unit 6 based on at least one of the type of resin supplied on the substrate and the characteristics of the pattern to be formed on the substrate. The mixing ratio of the reactive gas and the condensable gas may be determined. Information on the type of resin supplied on the substrate and information on the characteristics of the pattern to be formed on the substrate are included in the recipe for imprint processing. Therefore, a table representing the relationship between the concentration of the condensable gas in the mixed gas and the contraction rate of the pattern for each type of resin (FIG. 2A), or a table for each type of pattern features (FIG. 2 ( b)) is stored. Then, if the mixing ratio is determined using the relationship corresponding to the type of the resin 12 supplied on the substrate of the table or the relationship corresponding to the type of feature of the pattern to be formed on the substrate of the table. Good. Further, a table representing the relationship between the concentration of the condensable gas in the mixed gas and the shrinkage rate of the pattern for each combination of the resin type and the pattern feature type may be stored. Then, the mixing ratio may be determined using a relationship corresponding to the combination of the type of the resin 12 supplied on the substrate of the table and the type of feature of the pattern to be formed on the substrate. At this time, as described above, by determining the mixing ratio so that the concentration of the condensable gas is maximized within a range in which the shrinkage rate of the pattern formed on the substrate is allowed, accurate pattern formation and throughput can be improved. It is possible to achieve both improvement. When determining the mixing ratio in the mixed gas based on the information on the type of resin supplied on the substrate or the information on the type of pattern feature to be formed on the substrate, the imprint apparatus 1 uses the measuring unit 15. There is no need to have. For example, a pattern shape evaluation value obtained by measuring a pattern with an external measuring device such as SEM or AFM can be used.

  As described above, according to the imprint apparatus 1 of the present embodiment, an optimal mixed gas mixture ratio that does not deteriorate the shape of the pattern formed on the substrate 10 regardless of the type of the resin 12 or the type of pattern features. Can be determined. Therefore, the imprint apparatus 1 can provide an article such as a high-quality semiconductor device with high throughput and high economic efficiency while achieving both accurate pattern formation and throughput. A method for manufacturing a device (semiconductor device, magnetic storage medium, liquid crystal display element, etc.) as an article will be described. Such a manufacturing method includes a step of forming a pattern on a substrate (wafer, glass plate, film-like substrate, etc.) using the imprint apparatus 1. The manufacturing method further includes a step of processing the substrate on which the pattern is formed. The processing step may include a step of removing the remaining film of the pattern. Further, it may include other known steps such as a step of etching the substrate using the pattern as a mask. The method for manufacturing an article in the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article as compared with the conventional method.

  As mentioned above, although preferable embodiment of this invention was described, it cannot be overemphasized that this invention is not limited to these embodiment, A various deformation | transformation and change are possible within the range of the summary.

1: Imprinting device 6: Gas supply unit 7: Control unit 8: Mold 10: Substrate 21: Condensable gas supply unit

Claims (7)

An imprint apparatus for forming a pattern on the substrate by performing a mold on an imprint material on the substrate,
A supply unit for supplying a condensable gas that can be liquefied by the mold into a space between the mold used for the mold and the substrate;
Varies by the line width of the pattern to be formed, based on the relationship between the concentration of the condensable gas in information and the spatial characteristics of the pattern formed on the substrate, is supplied Ri by the said supply unit A control unit for controlling the concentration of the condensable gas in the space ;
An imprint apparatus comprising: An imprint apparatus for forming a pattern on the substrate by performing a mold on an imprint material on the substrate,
A supply unit for supplying a condensable gas that can be liquefied by the mold into a space between the mold used for the mold and the substrate;
Information on the characteristics of the pattern formed on the substrate and the concentration of the condensable gas in the space , which differs depending on the combination between the type of the imprint material and the type of line width of the pattern to be formed based on the relationship, of the condensable gas supplied Ri by the supply unit, and a control unit for controlling the concentration in the space,
An imprint apparatus comprising: The condensable gas, pentafluoropropane, imprint apparatus according to claim 1 or 2, characterized in that it comprises at least one of a hydrofluorocarbon and a hydrofluoroether. 4. The device according to claim 1, wherein the feature of the pattern formed on the substrate includes at least one of shrinkage rate, cross-sectional shape, height, and surface roughness. The imprint apparatus described in 1. Forming a pattern on a substrate using the imprint apparatus according to any one of claims 1 to 4 ,
Processing the substrate on which the pattern is formed in the step;
Have a method for producing an article, characterized in that the production of articles from processed the substrate. An imprint method for forming a pattern on the substrate by performing a mold on an imprint material on the substrate,
Supplying the condensable gas that can be liquefied by the mold into the space between the mold used for the mold and the substrate, and performing the mold;
Varies by the line width of the pattern to form the shape, based on the relationship between the concentration of the condensable gas in information and the spatial characteristics of the pattern formed on the substrate, of the condensable gas supplied, Controlling the concentration in the space ;
An imprint method characterized by the above. An imprint method for forming a pattern on the substrate by performing a mold on an imprint material on the substrate,
Supplying the condensable gas that can be liquefied by the mold into the space between the mold used for the mold and the substrate, and performing the mold;
And the concentration of the condensable gases varies depending on the combination, characterized information of the pattern to be formed on the substrate in the space between the kinds of line width of the pattern type and to be formed before Symbol imprint material Based on the relationship , the concentration of the condensable gas to be supplied is controlled in the space .
An imprint method characterized by the above.

Images