JP2013118280A - Measuring method, imprint device, and method of manufacturing article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique advantageous in measuring the thickness of a recessed part of a rugged pattern formed by an imprint device.SOLUTION: There is provided the measuring method of measuring the thickness of the recessed part of the rugged pattern by using correspondence information showing correspondence between characteristics of reflected light obtained from the rugged pattern by making light incident on a rugged pattern of resist formed on a substrate by the imprint device and a plurality of shapes of the rugged pattern, the measuring method including a first step of measuring the thickness of a projection part of the rugged pattern by a scanning probe microscope, and a second step of finding the thickness of the recessed part by using a result of measurement of characteristics of the reflected light from the rugged pattern by an optical measuring instrument and limited correspondence information, the correspondence information being limited to correspondence information corresponding to the thickness measured in the first step.

Description

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

  The imprint technique is expected as a technique for forming a fine pattern because it does not require a large-scale apparatus such as a vacuum process and can mass-produce semiconductor devices at low cost. In the imprint technology, a resin (imprint material) on a substrate such as a silicon wafer or a glass plate is in contact with a mold (mold) on which a fine pattern is formed, and the resin is cured to form a pattern on the substrate. It is a technology to transcribe.

  One of the differences between the imprint technique and conventional optical lithography is that a thin resin layer (called “residual film”) remains on the bottom of the pattern after the pattern is transferred. Therefore, in the semiconductor process, a step of removing the remaining film by etching is necessary. When removing the remaining film, etching is performed not only in the vertical direction (direction in which the remaining film is removed) but also in the horizontal direction. Therefore, when the remaining film thickness varies, the resist pattern shape (dimensions) such as the line width, side wall angle, and height of the pattern also varies. Since the resist pattern functions as an etching mask, when the dimension of the resist pattern changes from a desired dimension, the final device pattern dimension also changes, and as a result, the characteristics of the semiconductor device may vary and cause malfunction. Therefore, in an imprint apparatus using an imprint technique, it is essential to measure the remaining film thickness with high accuracy. It is important to determine (optimize) the process conditions (processing conditions) of the imprint apparatus based on the measurement result of the remaining film thickness, and to control (manage) the remaining film thickness.

  As a technique for measuring the remaining film thickness, there is a method in which a substrate on which a resist pattern is formed is cut and a cross section thereof is observed with a scanning electron microscope (SEM: Scanning Electron Microscope). However, the cross-sectional observation by the SEM requires cutting the substrate (that is, destructive measurement), and thus the substrate used for measurement cannot be reused.

  There is also proposed a scatterometry method for irradiating a measurement object with light and analyzing the intensity ratio and phase difference between S-polarized light and P-polarized light in the reflected light to obtain the shape of the measurement object (Patent Literature). 1). The scatterometry method is highly accurate and non-destructive (non-contact) in the shape of a resist pattern, as compared with SEM that includes effects such as pattern width (Line Width Roughness) and reduction (Shrink). It can be measured.

Japanese translation of PCT publication No. 2004-510152

  However, when the scatterometry method is applied to the measurement of the remaining film thickness, it is difficult to measure the resist pattern height (HT: Height) and the remaining resist film thickness (RLT: Residual Layer Thickness) separately. It is.

  FIG. 10A is a diagram showing a resist pattern formed by an imprint process, in which 1001 is a substrate, 1002 is an adhesion layer, 1003 is a remaining resist film, and 1004 is a resist pattern (resist protrusion). is there. Here, a case where the height (HT) of the resist pattern 1004 is changed and a case where the remaining film thickness (RLT) of the remaining film 1003 is changed are considered. In this case, since the optical constants (refractive index n, absorption coefficient k) of the materials constituting the resist pattern 1004 and the remaining film 1003 are the same, the result of measuring the resist pattern 1004 by the scatterometry method is as follows. There is no significant difference between them. Therefore, it is difficult to distinguish whether the HT has changed or the RLT has changed from the measurement result by the scatterometry method.

  The problem will be further described using the results of simulation with a vector diffraction model optical simulator (RCWA: Rigorous Coupled Wave Analysis) by changing RLT and HT among the resist pattern shapes. FIG. 10B shows the S-polarized spectral reflection intensity when the RLT is changed by 0.2 nm from the design value, and the S-polarized spectral reflection intensity when the HT is changed by 0.3 nm from the design value. FIG. FIG. 10C is a diagram showing a difference from the design value of the spectral reflection intensity shown in FIG. Referring to FIG. 10B and FIG. 10C, the change in the spectral reflection intensity due to the change in RLT and the change in the spectral reflection intensity due to the change in HT show the same tendency, which is 0.5 μm or more. It can be said that there is no difference between the two in the wavelength band. Thus, if there are a plurality of solution candidates for one spectral reflection intensity, the solution cannot be uniquely determined.

  An object of the present invention is to provide a technique advantageous for measuring the thickness of a concave portion of a concavo-convex pattern formed by an imprint apparatus.

  In order to achieve the above object, a measurement method according to one aspect of the present invention is characterized in that light is incident on a concavo-convex pattern of a resist formed on a substrate by an imprint apparatus and the characteristics of reflected light obtained from the concavo-convex pattern And measuring the thickness of the concave portion of the concave / convex pattern using correspondence information indicating the correspondence between each of the plurality of shapes of the concave / convex pattern and scanning the thickness of the convex portion of the concave / convex pattern. The first step of measuring with a probe microscope and the correspondence information are limited to correspondence information corresponding to the thickness measured in the first step, and the characteristic of the reflected light from the concavo-convex pattern is measured by the optical measurement device. And a second step of determining the thickness of the recess using the result of the measurement in step (b) and the limited correspondence information.

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

  ADVANTAGE OF THE INVENTION According to this invention, the technique advantageous to the measurement of the thickness of the recessed part of the uneven | corrugated pattern formed by the imprint apparatus can be provided, for example.

It is the schematic which shows the structure of the measuring apparatus used for measurement of a residual film thickness (RLT). It is a flowchart for demonstrating the measuring method as 1 side surface of this invention. It is sectional drawing which shows the uneven | corrugated pattern of the resist formed on the board | substrate. It is sectional drawing which shows the uneven | corrugated pattern of the resist formed on the board | substrate. It is sectional drawing which shows the uneven | corrugated pattern of the resist formed on the board | substrate. It is a flowchart for demonstrating the measuring method as 1 side surface of this invention. It is a figure for demonstrating the several shot area | region arrange | positioned on a board | substrate. It is the schematic which shows the structure of the imprint apparatus as 1 side surface of this invention. 3 is a flowchart for explaining the operation of the imprint apparatus shown in FIG. 1. It is a figure for demonstrating the subject at the time of applying a scatterometry method to the measurement of a residual film thickness (RLT).

  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.

<First Embodiment>
A measurement method as one aspect of the present invention will be described. Such a measuring method is a method of measuring a residual film thickness (RLT) which is a thickness of a concave portion of a concavo-convex pattern of a resist formed on a substrate by an imprint apparatus using an optical measuring device.

  With reference to FIG. 1, the optical measuring device 100 used for measurement of RLT is demonstrated. The optical measurement device 100 is a measurement device that measures the shape (cross-sectional shape) of a concavo-convex pattern, which is an object to be measured, using a scatterometry method. The shape of the concavo-convex pattern is defined by RLT, the height (HT) of the resist pattern that is the thickness of the convex portion, the pattern line width (CD: Critical Dimension), the side wall angle (SWA: Side Wall Angle), and the like.

  The scatterometry method is roughly classified into the following two methods. In the first method, broadband light including light of a plurality of wavelengths is incident on a concavo-convex pattern at a constant incident angle (obliquely incident), and reflected light from the concavo-convex pattern (for example, characteristics (for example, Strength)). The second method is a method in which light having a single wavelength is incident on the concavo-convex pattern at a plurality of incident angles, and the reflected light (characteristics) from the concavo-convex pattern is measured for each of the plurality of incident angles. Here, the case where the first method is used as the scatterometry method will be described, but the second method can also be used.

  As shown in FIG. 1, the light La emitted from the light source 102 passes through a rotatable polarizer 104, the polarization plane (S-polarized light, P-polarized light) is adjusted, and is incident on the concavo-convex pattern (periodic pattern) PT. The light Lb reflected by the concavo-convex pattern PT passes through the rotatable analyzer 106 and the plane of polarization is adjusted. The light Lc that has passed through the analyzer 106 is spatially wavelength-separated by the spectroscopic optical system 108 according to the wavelength. The spatially wavelength-separated light Ld is detected by the detection unit 110 in which photoelectric conversion elements are arranged in an array, and the information is sent to the computer 112. The calculator 112 calculates an intensity ratio and a phase difference between S-polarized light and P-polarized light for each wavelength based on information from the detection unit 110. Then, the computer 112 compares the calculation result (measurement result) with the library information to obtain the shape of the concavo-convex pattern PT, and the result is output from the computer 112 as the shape of the concavo-convex pattern PT.

  FIG. 2 is a flowchart for explaining a measurement method according to one aspect of the present invention. FIG. 3 is a cross-sectional view showing a concavo-convex pattern 35 of a resist formed on the substrate 31. The concavo-convex pattern 35 includes a residual film (concave portion) 33 and a resist pattern (convex portion) 34, and is formed on the adhesion layer 32 laminated on the substrate 31 by an imprint apparatus.

  With reference to Fig.2 (a), the whole process of the measuring method as 1 aspect of this invention is demonstrated. In S1 (first step), the height HT of the resist pattern 34 of the concavo-convex pattern 35 formed on the substrate 31 is measured with a scanning probe microscope (SPM: Scanning Probe Microscope). Specifically, as shown in FIG. 3, by scanning the probe Pr of the SPM along the scanning path Sc, that is, the direction perpendicular to the longitudinal direction (Y-axis direction) of the resist pattern 34 (X-axis direction). Then, the height HT of the resist pattern 34 is measured. The SPM includes an atomic force microscope (AFM), a scanning tunneling microscope (Scanning Tunneling Microscope), and the like.

  In S2 (third step), a library (library information) for measuring the remaining film thickness RLT by the optical measuring device 100 is created using the height HT of the resist pattern 34 measured in S1. Specifically, among the parameters that define the shape of the concavo-convex pattern 35, the value of the parameter representing the height HT of the resist pattern 34 is fixed (limited) with the value of the height HT of the resist pattern 34 measured in S1. Next, a plurality of shapes of the concavo-convex pattern 35 are set by changing values of parameters (for example, other dimensions such as RLT, CD, and SWA) excluding the height HT of the resist pattern 34, and the concavo-convex corresponding to each shape The intensity of the reflected light from the pattern 35 is calculated by simulation. Then, information (correspondence information) indicating the correspondence between the intensity of the reflected light from the concave / convex pattern 35 when the light is incident on the concave / convex pattern 35 and the shape of the concave / convex pattern 35 is generated for each shape of the concave / convex pattern 35. To create a library containing such information. For the simulation, for example, RCWA (Rigorous Coupled Wave Analysis) that solves the eigenvalue equation by expressing the electric field in the structure having periodicity by Fourier transform may be used.

  In S3 (second step), the remaining film thickness RLT of the remaining film 33 of the uneven pattern 35 formed on the substrate 31 is determined. First, the uneven pattern 35 formed on the substrate 31 is measured by the optical measuring device 100. As described above, in the optical measurement device 100, the light from the light source 102 is incident on the concave / convex pattern 35, and the reflected light from the concave / convex pattern 35 is detected by the detection unit 110. Then, the information that most closely matches the intensity of the reflected light detected by the detection unit 110 (measurement result measured by the optical measurement device 100) is identified from the library created in S2, and the shape corresponding to the information is defined in the uneven pattern 35. By determining the shape, the remaining film thickness RLT of the remaining film 33 is determined.

  Thus, the height HT of the resist pattern 34 is measured by SPM, and the measurement result is reflected in the library (that is, the library is created by fixing the height HT measured by SPM). In the optical measurement device 100 (scatterometry method), it is difficult to distinguish from the measurement result whether the HT has changed or the RLT has changed. Therefore, by measuring (determining) HT with SPM, the measurement result of the optical measurement apparatus 100 reflects only RLT (change). Thereby, the measuring method of this embodiment can measure the residual film thickness RLT of the residual film 33 of the concavo-convex pattern 35 of the resist formed by the imprint apparatus with high accuracy.

  Details of library creation (S2) will be described with reference to FIG. In S <b> 21, the shape of the uneven pattern 35 formed on the substrate 31 by the imprint apparatus is defined on the computer 112. Here, a concavo-convex pattern 35 including a resist pattern 34 having a height HT measured in S1 is defined.

  In S22, the optical constant to be input to the simulator is determined on the computer 112. Here, the optical constant includes a refractive index, an absorption coefficient, and the like of a material (imprint material) constituting the uneven pattern 35. In the present embodiment, the incident angle of light incident on the concave / convex pattern 35 is fixed, and reflected light from the concave / convex pattern 35 is detected for each wavelength while changing the wavelength of the light. Therefore, the optical constant is determined for each wavelength of the material constituting the uneven pattern 35.

  In S23, the optical system conditions of the optical measuring device 100 to be input to the simulator are determined on the computer 112. Here, the optical system conditions of the optical measurement device 100 include the incident angle, wavelength, and polarization direction of light incident on the concavo-convex pattern 35, the polarization direction of reflected light from the concavo-convex pattern 35, and the like.

  In S24, the simulator 112 calculates the intensity of the reflected light from the concavo-convex pattern 35 based on the shape of the concavo-convex pattern 35 defined in S21 or S27, the optical constant determined in S22, and the optical system condition determined in S12. Calculate with

  In S25, information indicating the correspondence between the intensity of the reflected light from the uneven pattern 35 calculated in S24 and the shape of the uneven pattern 35 defined in S21 or S27 is stored in the library. The library is a database in which information (intensity and phase) of the shape of the concavo-convex pattern that is the object to be measured and the reflected light from the concavo-convex pattern (shape) is associated and stored.

  In S <b> 26, it is determined whether information indicating the correspondence relationship between the intensity of the reflected light from the concavo-convex pattern 35 and the shape of the concavo-convex pattern 35 is stored for all the shapes of the concavo-convex pattern 35. Here, all the shapes of the concavo-convex pattern 35 mean all the shapes of the concavo-convex pattern 35 formed by the imprint apparatus (that is, within an assumed range). When the information is stored for all the shapes of the uneven pattern 35, the process is terminated. On the other hand, if the information is not stored for all the shapes of the concavo-convex pattern 35, the process proceeds to S27.

  In S27, the shape of the concavo-convex pattern 35 that does not store the information indicating the correspondence between the intensity of the reflected light from the concavo-convex pattern 35 and the shape of the concavo-convex pattern 35 is defined on the computer 112 as the shape of the new concavo-convex pattern 35. To do. Thereby, the intensity of the reflected light from the new uneven pattern 35 is calculated (S24), and information indicating the correspondence between the intensity of the reflected light and the shape of the new uneven pattern 35 is stored (S25). However, when defining the shape of the new concavo-convex pattern 35, the height HT of the resist pattern 34 is fixed to the SPM measurement result in S1, and the residual film thickness RLT, the line width CD of the pattern, the side wall angle Note that SWA is changed. In this way, the intensity of the reflected light from the concavo-convex pattern 35 with respect to each of a plurality of combinations of the thickness (HT) of the convex portion of the concavo-convex pattern 35 and other dimension values that define the shape of the concavo-convex pattern 35. Can be obtained by simulation.

<Second Embodiment>
In the first embodiment, in S1, the SPM probe Pr is scanned along the scanning path Sc, that is, in a direction (X-axis direction) perpendicular to the longitudinal direction (Y-axis direction) of the resist pattern 34. A height HT of 34 is measured (see FIG. 3). In other words, the height HT of the resist pattern 34 having a clearance necessary for measurement by SPM in the periphery thereof is measured. However, there may be a case where the line width interval of the resist pattern 34 is finer than the SPM probe Pr (its diameter). In such a case, since the probe Pr of SPM cannot be inserted between (inside) the resist pattern 34, it is impossible to scan the probe Pr along the scanning path Sc.

  Therefore, in the present embodiment, when the height HT of the resist pattern 34 is measured, the probe Pr is located at the boundary between the pattern region where the resist pattern 34 is formed and the non-pattern region where the resist pattern 34 is not formed. Scan.

  FIG. 4 is a cross-sectional view showing the concavo-convex pattern 35 of the resist formed on the substrate 31. The concavo-convex pattern 35 has a pattern region α in which a resist pattern 34 is formed (that is, convex portions are periodically formed) and a resist pattern 34 is not formed (that is, only a concave portion is formed). ) Non-pattern region β.

  Referring to FIG. 4, when the SPM probe Pr cannot be inserted between the resist patterns 34, the height HT of the resist pattern 34 cannot be measured as described above. Therefore, as shown in FIG. 4, the scanning path Sc of the SMP probe Pr is set at the boundary between the pattern region α and the non-pattern region β. Specifically, the scanning path Sc is set so that the resist pattern 34 ′ closest to the non-pattern area β among the resist patterns 34 formed in the pattern area α adjacent to the non-pattern area β is scanned by the probe Pr. To do. Accordingly, the height HT of the resist pattern 34 ′ can be measured by scanning the probe Pr of SPM along the scanning path Sc. Therefore, it is possible to create a library for measuring the remaining film thickness RLT by the optical measurement apparatus 100 using the height HT of the resist pattern 34 '(S2).

<Third Embodiment>
In the second embodiment, when the SPM probe Pr cannot be inserted between the resist patterns 34, the resist pattern 34 ′ closest to the non-pattern region β among the resist patterns 34 formed in the pattern region α. Is measured. However, when the uneven pattern 35 formed on the substrate 31 does not include the non-pattern region β, the height HT of the resist pattern 34 ′ cannot be measured.

  Therefore, in this embodiment, when measuring the height HT of the resist pattern 34, the resist pattern 34 formed in a part of the pattern region is removed to form a removal region, and the pattern region and the removal region The probe Pr is scanned in the vicinity of the boundary. In other words, a clearance necessary for measurement by SPM is formed in the resist pattern 34.

  FIG. 5 is a cross-sectional view showing the concavo-convex pattern 35 of the resist formed on the substrate 31. The uneven pattern 35 includes only the pattern region α where the resist pattern 34 is formed, and does not include the non-pattern region β where the resist pattern 34 is not formed.

  Referring to FIG. 5A, when the uneven pattern 35 does not include the non-pattern region β and the SPM probe Pr cannot be inserted between the resist patterns 34, as described above, the resist pattern 34 The height HT cannot be measured. Therefore, as shown in FIG. 5B, the resist pattern 34 ″ formed in a part of the pattern region α, the remaining film 33 and the adhesion layer 32 thereunder are removed (that is, the substrate 31). To form a removal region γ. However, instead of exposing the substrate 31, the adhesion layer 32 may be exposed by removing the resist pattern 34 ″ and the remaining film 33 below the resist pattern 34 ″.

  When removing the resist pattern 34 ″, the remaining film 33, and the adhesion layer 32, a microfabrication apparatus having a generation source for generating a focused ion beam (FIB), an electron beam, a laser, or the like is used. Is possible. Further, when removing the resist pattern 34 ″, the residual film 33, and the adhesion layer 32, it is necessary to stop processing (removal) on the substrate surface, and therefore, the difference in etching selectivity between the adhesion layer 32 and the substrate 31. Is better. The determination of whether or not the resist pattern 34 ″, the remaining film 33, and the adhesion layer 32 have been removed can be inferred from, for example, processing time and etching selectivity. Specifically, a correlation between the processing time and the etching selection ratio is obtained for the material constituting each of the concave / convex pattern 35 and the adhesion layer 32, and based on the correlation, a resist pattern 34 '' and a remaining film 33 are obtained. Whether or not the adhesion layer 32 has been removed is determined.

  By forming the removal region γ, as shown in FIG. 5C, it is possible to set the scanning path Sc of the SMP probe Pr in the vicinity of the boundary between the pattern region α and the removal region γ. Specifically, the scanning path Sc is set so that the resist pattern 34 ′ closest to the removal region γ is scanned by the probe Pr among the resist patterns 34 formed in the pattern region α adjacent to the removal region γ. Accordingly, the height HT of the resist pattern 34 ′ can be measured by scanning the probe Pr of SPM along the scanning path Sc. Therefore, it is possible to create a library for measuring the remaining film thickness RLT by the optical measurement apparatus 100 using the height HT of the resist pattern 34 '(S2).

<Fourth Embodiment>
In the first to third embodiments, the resist pattern height HT is measured by SPM, and the measurement result is reflected in the library, whereby the resist pattern height HT is measured with high accuracy. Realized. In the first to third embodiments, it is assumed that the height HT of the resist pattern in the concavo-convex pattern formed in each shot region on the substrate does not vary. However, the resist pattern height HT may vary between shot regions. In such a case, the resist pattern height HT in each shot area cannot be measured with high accuracy simply by measuring the resist pattern height HT in one shot area and reflecting the measurement result in the library. . Although it is conceivable to measure the height HT of the resist pattern in each shot area and create a library in which the measurement result is reflected for each shot area, enormous time is required to create the library.

  Therefore, in the present embodiment, the measurement result of SMP in each shot region is handled from a library including a plurality of information indicating the relationship between the intensity of reflected light from the concavo-convex pattern 35 and each of the plurality of shapes of the concavo-convex pattern 35. Select information. Here, the plurality of shapes of the concavo-convex pattern 35 refers to changing the value of a parameter representing the height HT of the resist pattern 34 within an assumed range, and the remaining film thickness RLT, the line width CD of the pattern, and the sidewall angle SWA. This is a shape defined by changing a parameter representing.

  With reference to Fig.6 (a), the measuring method in this embodiment is demonstrated. Here, it is assumed that a library including a plurality of pieces of information indicating the relationship between the intensity of reflected light from the concavo-convex pattern 35 and each of the plurality of shapes of the concavo-convex pattern 35 is created in advance.

  The measurement method shown in FIG. 6A is effective when the resist pattern height HT varies between shot regions on the substrate as described above. Therefore, before performing the measurement method shown in FIG. 6A, it is preferable to determine whether or not the resist pattern height HT varies between shot regions on the substrate. For example, as shown in FIG. 7, considering a case where a plurality of shot areas are arranged on the substrate, the resist pattern height HT in each of the plurality of shot areas is measured by SPM. Then, by evaluating the measurement result of SPM with 3σ or the like, it is determined whether or not the height HT of the resist pattern varies between shot regions. Here, if the resist pattern height HT does not vary between shot regions, a library is created using the average resist pattern height HT in each shot region as a representative value of the resist pattern height HT. The remaining film thickness RLT may be measured. When determining whether or not the resist pattern height HT varies between shot areas on the substrate, it is not necessary to measure the resist pattern height HT in all shot areas on the substrate. For example, the resist pattern height HT in specific shot areas S1 to S16 among a plurality of shot areas on the substrate is measured, and whether or not the resist pattern height HT varies between shot areas is determined from the measurement result. May be.

  In S61, the height HT of the resist pattern 34 of the concavo-convex pattern 35 formed in the target shot region on the substrate is measured by SPM. In S62, the remaining film thickness RLT of the remaining film 33 of the concavo-convex pattern 35 formed in the target shot region on the substrate is determined. Specifically, first, information having a value of the height HT of the resist pattern 34 measured in S61 is selected from a plurality of pieces of information included in the library. In other words, information indicating the relationship between the shape of the concavo-convex pattern 35 defined by the resist pattern 34 having the height HT measured in S61 and the intensity of reflected light from the concavo-convex pattern 35 is selected. Next, the unevenness pattern 35 formed in the target shot area on the substrate is measured by the optical measuring device 100. As described above, in the optical measurement device 100, the light from the light source 102 is incident on the concave / convex pattern 35, and the reflected light from the concave / convex pattern 35 is detected by the detection unit 110. Then, information that most closely matches the intensity of the reflected light detected by the detection unit 110 (measurement result measured by the optical measurement device 100) is identified from the selected information described above, and the shape corresponding to the information is determined by the uneven pattern 35. By determining the shape, the remaining film thickness RLT of the remaining film 33 is determined.

  In S63, it is determined whether or not all shot areas on the substrate are set as target shot areas. If all the shot areas on the substrate are not the target shot areas, the process proceeds to S61, and the height HT of the resist pattern 34 is measured using the next shot area as the target shot area. On the other hand, when all the shot areas on the substrate are set as the target shot areas, the process ends.

  As described above, in this embodiment, the height HT of the resist pattern 34 in each shot area is measured by SPM, and information corresponding to the measurement result is selected from the library for each shot area. As a result, the measurement method of this embodiment allows the remaining film thickness RLT of the remaining film 33 of the uneven pattern 35 formed in each shot region even if the height HT of the resist pattern varies between shot regions on the substrate. Can be measured with high accuracy.

  FIG. 6A illustrates a case where a library including a plurality of pieces of information indicating the correspondence between the intensity of reflected light from the concavo-convex pattern 35 and each of the plurality of shapes of the concavo-convex pattern 35 is created in advance. . However, as shown in FIG. 6B, before the height HT of the resist pattern 34 of the uneven pattern 35 formed in the target shot region on the substrate is measured by SPM (S61), S60 (third step) In this case, a library may be created. Specifically, first, the height HT of the resist pattern 34 of the concavo-convex pattern 35 formed in one shot area among a plurality of shot areas on the substrate is measured by SPM (measurement step). Next, among parameters defining the shape of the concave / convex pattern 35, a parameter value indicating the height HT of the resist pattern 34 includes a predetermined SPM measurement result (actually measured height HT value of the resist pattern 34). Change the value within the range (within the expected range). At this time, a plurality of shapes of the concavo-convex pattern 35 are set by changing values of parameters other than the height HT of the resist pattern 34 (for example, other dimensions such as RLT, CD, and SWA). And the intensity | strength of the reflected light from the uneven | corrugated pattern 35 corresponding to each shape is calculated by simulation. Then, information indicating the correspondence between the intensity of the reflected light from the concave / convex pattern 35 when the light is incident on the concave / convex pattern 35 and the shape of the concave / convex pattern 35 is generated for each shape of the concave / convex pattern 35. Create a library that contains it.

<Fifth Embodiment>
In the fifth embodiment, an imprint apparatus as one aspect of the present invention will be described. FIG. 8 is a schematic diagram illustrating the configuration of the imprint apparatus 1. Referring to FIG. 8, a substrate (wafer) 11 is held by a chuck 12. The fine movement stage 13 has a function of correcting the rotation of the substrate 11 around the Z axis, a function of correcting the position of the substrate 11 in the Z axis direction, and a function of correcting the tilt of the substrate 11. The fine movement stage 13 is disposed on an XY stage 14 for positioning the substrate 11 at predetermined positions in the X-axis direction and the Y-axis direction. The fine movement stage 13 is mounted with a chuck 12 and a reference mirror (not shown) that reflects light from a laser interferometer that measures the position of the fine movement stage 13 in the X-axis direction and the Y-axis direction. Yes. The XY stage 14 is placed on the base surface plate 15. The fine movement stage 13 and the XY stage 14 constitute a substrate stage in this embodiment.

  A mold 16 on which a pattern to be transferred to the substrate 11 is formed is fixed to a mold chuck 17. The mold chuck 17 is placed on a mold stage 18 having a function of correcting the inclination of the mold 16 around the Z axis. The positions of the mold chuck 17 in the X-axis direction and the Y-axis direction are measured by a laser interferometer supported on the alignment shelf 19.

  Each of the mold chuck 17 and the mold stage 18 has an opening (not shown) that allows ultraviolet light irradiated from the ultraviolet light source 20 through the collimator lens to pass through the mold 16. Further, a load cell (not shown) having a function of detecting the pressing force (imprinting force) of the mold 16 is disposed on the mold chuck 17 (or the mold stage 18).

  One end of the guide bar plate 21 is fixed to the mold stage 18 and the other end of the guide bar 23 penetrating the top plate 22 is fixed. The mold raising / lowering linear actuator 24 is composed of an air cylinder or a linear motor, and drives the guide bar 23 in the Z-axis direction to press the mold 16 held by the mold chuck 17 against the substrate 11 or to separate it from the substrate 11. To do. The alignment shelf 19 is suspended from the top plate 22 via a support column 25. A guide bar 23 passes through the alignment shelf 19.

  The die-by-die alignment TTM (through-the-mold) alignment scope 26 includes an optical system and an imaging system for observing alignment marks provided on the substrate 11 and the mold 16. The TTM alignment scope 26 measures the positional deviation between the substrate 11 and the mold 16 in the X-axis direction and the Y-axis direction. Further, the alignment shelf 19 is provided with a height measurement system (not shown) for measuring the height (flatness) of the substrate 11 held on the chuck 12 by using, for example, an oblique incident image shift method. ing. The dispenser head 27 includes a nozzle that drops liquid photocurable resin (imprint material) onto the surface of the substrate 11 and has a function of supplying (applying) the resin to the substrate 11.

  The control unit 28 includes a CPU, a memory, and the like, and controls the entire imprint apparatus 1 (operation). For example, the control unit 28 feedback-controls the imprint processing unit (processing conditions thereof) based on the measurement result of the optical measurement device 100 (remaining film thickness (RLT) of the remaining film of the uneven pattern). Specifically, based on the measurement result of the optical measurement device 100, the control unit 28 controls the processing conditions of the imprint process so that the remaining film thickness of the remaining film of the uneven pattern becomes the target thickness. Here, the imprint processing unit is a generic name including each unit of the imprint apparatus 1. The imprint processing unit forms a concavo-convex pattern on the substrate 11 by forming the resin on the substrate 11 using the mold 16 and curing the resin, and then releasing (releasing) the mold 16 from the cured resin. I do.

  The optical measurement device 100 has a configuration as shown in FIG. 1 and measures the remaining film thickness (RLT) of the remaining film of the concavo-convex pattern formed on the substrate 11. In the present embodiment, the optical measuring device 100 includes a scanning probe microscope (SPM) that measures the height (HT) of the resist pattern of the concavo-convex pattern. However, the optical measurement device 100 and the scanning probe microscope may be provided separately.

  Hereinafter, the operation of the imprint apparatus 1 will be described with reference to FIG. Here, operations including optimization of processing conditions for imprint processing performed prior to mass production of semiconductor devices will be described. Further, the volume and distribution density of the resin supplied to the substrate 11 by the dispenser head 27 (that is, the supply amount of the resin supplied to the substrate 11) are set as processing conditions.

  In S <b> 200, substrates (for example, 25 substrates) included in one lot are carried into the imprint apparatus 1. In S210, an imprint process is performed on each of the substrates carried into the imprint apparatus 1 (that is, all the substrates in the lot) (a concavo-convex pattern is formed on the substrate). The imprint process includes an alignment process for each substrate, a resin supply process, a mold imprint process, a resin curing process, and a mold release process.

  In S220, a specific number of substrates (a plurality of substrates) are selected from the substrates subjected to the imprint process (substrates in the lot), and the remaining film thickness (RLT) of the uneven pattern formed on the substrates is selected. ). The RLT measurement is performed by the optical measurement device 100 as described in the above-described embodiment. However, since the concavo-convex pattern is formed in each of a plurality of shot regions (see FIG. 7) on the substrate, the optical measurement device 100 measures the RLT of the concavo-convex pattern formed in each shot region.

  In S230, based on the measurement result in S220, RLT variation (such as 3σ) between shot areas is calculated. In S240, it is determined whether the RLT variation between shot areas exceeds a threshold value. If the RLT variation between shot areas exceeds the threshold, the process proceeds to S250. On the other hand, if the variation in RLT between shot areas does not exceed the threshold, the process proceeds to S260.

  In S250, the processing conditions for the imprint process are optimized. Specifically, the amount of resin supplied to the substrate so that the variation in RLT between shot regions does not exceed the threshold value, that is, the RLT of the concavo-convex pattern formed in each shot region has a target thickness. Is optimized (determined). For example, for a shot region with a thick RLT, the amount of resin supplied is reduced, and for a shot region with a thin RLT, the amount of resin supplied is increased to reduce variations in RLT between shot regions. As described above, the reason why the amount of resin supplied to the substrate can be optimized is that the optical measurement apparatus 100 measures the RLT with high accuracy by measuring the height (HT) of the resist pattern by SPM. Because it can.

  In S260, it is determined whether imprint processing has been performed for all lots. If the imprint process has not been performed for all the lots, the process proceeds to S200, and the substrate included in the next lot is carried into the imprint apparatus 1. On the other hand, when the imprint process has been performed for all the lots, the operation is terminated.

  As described above, in this embodiment, the supply amount (processing conditions) of the resin supplied to the substrate can be controlled to an optimum state, and variations in RLT in each shot region of the substrate can be reduced.

  In this embodiment, the amount of resin supplied to the substrate is the processing condition. However, the pressure that causes the mold 16 to act on the resin may be the processing condition. The pressure at which the mold 16 acts on the resin can be adjusted using the mold lifting linear actuator 24 or the substrate stage. For example, for a shot region with a thick RLT, the mold pressure is increased, and for a shot region with a thin RLT, the mold pressure is decreased to reduce variations in RLT between shot regions. It is also possible to control both the amount of resin supplied to the substrate and the pressing force when pressing the mold.

  A method of manufacturing a device (semiconductor integrated circuit element, liquid crystal display element, etc.) as an article includes a step of forming a pattern on a substrate (wafer, glass plate, film substrate, etc.) using the imprint apparatus 1 described above. Further, the manufacturing method includes a step of etching the substrate on which the pattern is formed. When manufacturing other articles such as patterned media (recording media) and optical elements, the manufacturing method includes other processing for processing the substrate on which the pattern is formed instead of etching. The method for manufacturing an article according to 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.

Claims (9)

Correspondence information indicating the correspondence between the characteristics of reflected light obtained from the concavo-convex pattern by making light incident on the concavo-convex pattern of the resist formed on the substrate by the imprint apparatus and each of the plurality of shapes of the concavo-convex pattern A measuring method for measuring the thickness of the concave portion of the concave-convex pattern using
A first step of measuring the thickness of the convex portion of the concave-convex pattern with a scanning probe microscope;
The correspondence information is limited to the correspondence information corresponding to the thickness measured in the first step, the result of measuring the characteristic of the reflected light from the uneven pattern with an optical measurement device, and the limitation. A second step of determining the thickness of the recess using the corresponding relationship information,
A measurement method characterized by comprising: A third step of generating the correspondence information;
In the third step, the characteristics of the reflected light obtained from the concavo-convex pattern can be simulated for each of a plurality of combinations of the thickness of the convex portion of the concavo-convex pattern and values of other dimensions that define the shape of the concavo-convex pattern. The measuring method according to claim 1, further comprising a step of obtaining.   The measurement method according to claim 2, wherein the third step limits the thickness of the convex portion in the plurality of combinations to the thickness of the convex portion measured in the first step.   The measurement method according to claim 1, wherein the second step selects correspondence information corresponding to the thickness measured in the first step from correspondence information including the correspondence information.   The said 1st step measures the thickness of the convex part which has the clearance required for the measurement by the said scanning probe microscope in the circumference | surroundings with the said scanning probe microscope, The any one of Claim 1 thru | or 4 characterized by the above-mentioned. Measurement method according to item.   The measurement method according to claim 5, further comprising a step of forming the clearance with respect to the uneven pattern. An imprint processing unit for performing an imprint process for forming an uneven pattern on the substrate by molding an imprint material on the substrate with a mold;
A control unit that controls processing conditions of the imprint processing so that the thickness of the concave portion of the concave-convex pattern measured by the measurement method according to any one of claims 1 to 6 becomes a target thickness; ,
An imprint apparatus comprising:   The imprint according to claim 7, wherein the processing condition includes a condition related to at least one of supply of an imprint material onto the substrate and pressure applied to the imprint material by the mold. apparatus. Forming a pattern on a substrate using the imprint apparatus according to claim 7 or 8, and
Processing the substrate on which the pattern is formed in the step;
A method for producing an article comprising:

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