JP2012019111A - Measurement method, imprint apparatus, and manufacturing method of product - Google Patents

Abstract

To provide a highly accurate measurement technique for the thickness of a concave portion of a concave-convex pattern formed by an imprint apparatus.
A method for determining the thickness of a concave / convex pattern concave portion of a resist using a spectroscopic ellipsometry method, wherein the measurement accuracy with respect to the difference between the thickness of the convex portion of the concave / convex pattern and the thickness of the concave portion is obtained. The first step of measuring the intensity of the reflected light in the first polarization state for a plurality of wavelengths with a large difference in measurement accuracy with respect to the thickness of the recess, and the thickness of the recess based on the measurement results in the first step In the first step, the third step of measuring the intensity of the reflected light in the second polarization state with excellent measurement accuracy with respect to the thickness of the recess, and the measurement in the third step Based on the result, the fourth step for obtaining the plurality of thicknesses of the recesses with the third accuracy, the thickness obtained in the second step from the plurality of thicknesses obtained in the fourth step, and the first accuracy And select a thickness that is within the range of thicknesses Including a fifth step of obtaining a thickness of said recess.
[Selection] Figure 1

Description

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

  The imprint technology enables mass production at low cost without requiring a large-scale apparatus such as a vacuum process. Therefore, it is expected to be applied as a technique for forming a fine pattern with high precision in place of conventional photolithography in next-generation semiconductor processes. According to the technology strategy roadmap formulated by the Ministry of Economy, Trade and Industry, 2013 (32 nm technology node) is listed as the target year for applying imprint technology to semiconductor processes. Application of imprint technology to semiconductor processes is positioned as one of the specific industrial needs in the next-generation semiconductor industry.

  In general, in the imprint technique, after the mold is released, the concave portion of the concave / convex pattern remains as an ultrathin residual film having a thickness of about several tens of nanometers other than the resist cured portion (fine pattern forming portion). A process for removing the residual film is required. Since the resist hardened portion functions as an etching mask, if the remaining film varies, the pattern size after etching varies, and as a result, the characteristics of the semiconductor device vary, causing defects. In order to solve such problems and apply the imprint technology to the semiconductor process with high reliability, it is necessary to establish a technology for accurately controlling the remaining film thickness of about several tens of nanometers generated during imprinting. is there. For that purpose, highly accurate measurement of the residual film thickness of the resist is indispensable. Patent Document 1 describes measuring the remaining film thickness and pattern dimensions, but does not disclose a specific method for measuring the remaining film thickness. In semiconductor manufacturing, oxide films, nitride films, and metal films are used as semiconductor device structures, and there are many methods for measuring the film thickness. In particular, measurement methods using ellipsometry are widely used. .

JP 2010-030153 A

  When measuring the cross-sectional shape of the concavo-convex pattern using the ellipsometry method to measure the residual film thickness formed by imprinting, the height of the concavo-convex pattern and the residual film thickness of the resist can be measured separately. The problem of difficulty arises. Specifically, the problem will be described with reference to FIG. FIG. 4A is a diagram illustrating a concavo-convex pattern formed by the imprint process. 4B and 4C are diagrams in which only the resist portion is extracted. When the total height h of the resist portion is the same, if the residual film thickness (Residual Layer Thickness: RLT) changes from FIG. 4B to FIG. 4C, the pattern height (Hight: HT) also changes accordingly. To do. The pattern portion and the remaining film portion of the resist portion are the same resist resin. Therefore, their optical constants (refractive index n, absorption coefficient k) are the same, and it is assumed that the output (spectral characteristics) obtained by measuring the resist patterns of FIGS. 4B and 4C by the ellipsometry method is not significantly different. Therefore, it is difficult to distinguish whether the remaining film thickness has changed or the pattern height has changed from the result of the spectral characteristics.

  This will be further described using the results of simulation with an optical simulator (for example, RCWA) of a vector diffraction model in which the remaining film thickness (RLT) and the pattern height (HT) are variously changed in the cross-sectional shape of the pattern. FIG. 5A shows the result of spectral characteristics when RLT and HT are variously changed when the measurement condition is 0 degree polarization. FIG. 5B shows the relationship between the difference from the nominal intensity value and the wavelength, and changes due to HT and changes due to RLT are mixed. In the region indicated by the region A having a wavelength region from 0.5 μm to a high wavelength region, there are a plurality of combinations of RLT and HT that indicate the same spectral characteristic output (intensity difference). FIG. 5C is a schematic diagram of FIG. 5B when the horizontal axis is RLT and HT is a parameter. In the examples of FIGS. 5B and 5C, when the combination of RLT and HT is (RLT1, HT1), (RLT2, HT2), (RLT3, HT3), the same intensity difference is shown in region A. Therefore, the RLT cannot be specified from the spectral characteristic output. Patent Document 1 does not disclose a specific method for measuring the remaining film thickness, and does not point out a problem that the pattern height and the resist remaining film thickness cannot be separated.

  The present invention has been made in view of the above circumstances, and exemplifies the provision of a measurement technique that is advantageous in terms of accuracy in measuring the thickness (remaining film thickness) of the concave portion of the concave-convex pattern formed by the imprint apparatus. Objective purpose.

  In the present invention, light of a plurality of wavelengths is obliquely incident on a resist concavo-convex pattern formed on a substrate by an imprint apparatus with a constant incident angle, and the intensity of reflected light from the concavo-convex pattern is measured for each of the plurality of wavelengths. And measuring the thickness of the concave portion of the concave / convex pattern from information indicating the relationship between the intensity measured for each of the plurality of wavelengths and the shape of the concave / convex pattern and the measurement result, The convexity of the concavo-convex pattern measured using the reflected light of the first polarization state, with the measurement accuracy relating to the thickness of the concave portion measured using the reflected light of the first polarization state from the pattern as the first accuracy The measurement accuracy related to the difference between the thickness of the concave portion and the thickness of the concave portion is the second accuracy, and the concave portion measured using the reflected light in the second polarization state from the concave-convex pattern The measurement accuracy related to the thickness is the third accuracy, and the measurement accuracy related to the difference between the thickness of the convex portion of the concave / convex pattern and the thickness of the concave portion measured using the reflected light in the second polarization state is the fourth accuracy The first accuracy is superior to the second accuracy but inferior to the third accuracy, and the difference between the first accuracy and the second accuracy is the third accuracy and the fourth accuracy. The first polarization state and the second polarization state are set to be greater than the difference between the first polarization state and the first step of measuring the intensity of the reflected light in the first polarization state for each of the plurality of wavelengths; and the first step A second step of obtaining the thickness of the concave portion with the first accuracy based on the measurement result in the first step and the information; and a third step of measuring the intensity of the reflected light in the second polarization state for each of the plurality of wavelengths. Step, the result of measurement in the third step and the step A fourth step of obtaining a plurality of thicknesses of the recesses with the third accuracy based on the information, a thickness obtained in the second step from a plurality of thicknesses obtained in the fourth step, and the And a fifth step of obtaining a thickness of the recess by selecting a thickness within a range of thicknesses determined from the first accuracy.

  ADVANTAGE OF THE INVENTION According to this invention, the measurement technique advantageous in the point of the precision which measures the thickness (remaining film thickness) of the recessed part of the uneven | corrugated pattern formed, for example by the imprint apparatus can be provided.

The flowchart which shows the measuring method of 1st Embodiment. Configuration diagram of imprint device Control block diagram of imprint device The figure which shows the cross-sectional shape of the uneven | corrugated pattern formed with an imprint apparatus The figure which shows the spectral characteristic by the reflected light of 0 degree polarization Diagram showing the optical system of the measuring instrument The figure which shows the measuring method of the cross-sectional shape of an uneven | corrugated pattern Diagram showing the accuracy of RLT and HT The figure which shows the spectral characteristic by the reflected light of 45 degree polarization Diagram showing how to measure the remaining film thickness The figure which shows the shot layout of 3rd Embodiment It is a flowchart which shows 3rd Embodiment.

[First Embodiment]
A measurement method according to the first embodiment will be described. FIG. 2 is a diagram illustrating an example of the configuration of the imprint apparatus, and FIG. 3 is a diagram illustrating an example of a control block of the imprint apparatus. 2 and 3, the substrate (wafer) 1 is held by a wafer chuck 2. The fine movement stage 3 has a function of correcting the rotation of the wafer 1 around the z axis, adjusting the z position of the wafer 1, and correcting the tilt of the wafer 1, and is disposed on the XY stage 4. The fine movement stage 3 and the XY stage 4 are collectively referred to as a wafer stage. An XY stage 4 is placed on a base surface plate 5, and a reference mirror (not shown) that reflects light from a laser interferometer to measure the position of the fine movement stage 3 in the x and y directions on the fine movement stage 3. Is attached.

  A mold (mold) 10 on which a concave / convex pattern to be transferred to the wafer 1 is formed is fixed to a mold chuck 11 by a mechanical holding mechanism (not shown). The mold chuck 11 is placed on the mold chuck stage 12 by a mechanical holding mechanism (not shown). The mold chuck 11, the mechanical holding mechanism (not shown), and the mold chuck stage 12 constitute a support that supports the mold (mold 10). The mold chuck stage 12 has a function of correcting the rotation of the mold 10 (mold chuck 11) about the z axis and correcting the tilt of the mold 10. The mold chuck stage 12 has a mirror reflection surface (not shown) that reflects light from the laser interferometer in order to measure the position of the mold 10 in the x and y directions. The mold chuck 11 and the mold chuck stage 12 each have an opening (not shown) through which the UV light irradiated from the UV light source 16 through the collimator lens passes to the mold 10. One end of the guide bar plate 13 is fixed to the mold chuck stage 12 and the other end of the guide bar 14 penetrating the top plate 9 is fixed. The mold raising / lowering linear actuator 15 is composed of an air cylinder or a linear motor, and drives the guide bar 14 in the z direction to press the mold 10 held by the mold chuck 11 against or away from the wafer 1. The guide bar 14 penetrates the alignment shelf 18 suspended from the top plate 9 by the support column 19.

  A TTM (through-the-mold) alignment scope 20 for die-by-die alignment has an optical system and an imaging system for observing alignment marks provided on the wafer 1 and the mold 10. The TTM alignment scope 20 measures the positional deviation between the wafer 1 and the mold 10 in the x and y directions. The alignment shelf 18 is provided with a height measuring instrument (not shown) for measuring the height (flatness) of the wafer 1 on the wafer chuck 2 by using, for example, an oblique incident image shift method. The dispenser head (resist supply mechanism) 30 includes a resin dropping nozzle that drops liquid photo-curing resin (resist) on the surface of the wafer 1. The CPU (control unit) 40 controls the above-described actuators and sensors to cause the imprint apparatus 100 to perform a predetermined operation. The imprint apparatus 100 includes a memory 50. The imprint apparatus is connected to the measuring instrument 300 and the control apparatus 400 via the communication unit 500. The control device 400 is connected to the imprint apparatus 100 and the measuring instrument 300 via the communication unit 500, controls the entire semiconductor process, and feedback-controls information on the remaining film thickness from the measuring instrument 300 to the imprint apparatus 100. . A feedback control method will be described in an embodiment described later.

  The measuring instrument 300 has a thickness (remaining film thickness: RLT) of the concave / convex pattern of the resist formed on the wafer 1 and a difference thickness (pattern height: HT) between the thickness of the convex and the concave. ). The measuring device 300 is a device that measures a cross-sectional shape using an ellipsometry method, and is commercially available from a measuring device manufacturer as a device that measures CD (Critical Dimension, that is, the line width of an uneven pattern) using light. The measuring instrument 300 can measure not only the CD measurement but also the remaining film thickness (RLT), the height of the concavo-convex pattern (HT), the side wall angle (Side wall angle), and the like. In the present embodiment, the measurement device 300 is used to inspect the concavo-convex pattern of the resist formed on the wafer 1 to measure RLT and HT. The measuring instrument 300 will be described with reference to FIGS. FIG. 6 shows an example of an optical system of a measuring instrument 300 that measures the cross-sectional shape of the concavo-convex pattern using the ellipsometry method. The ellipsometry method includes a method of spectrally detecting the wavelength of reflected light when obliquely incident broadband light containing multiple wavelengths of light with a constant incident angle, and a single wavelength of light having multiple incident angles. There is a method of spectrally detecting the wavelength of reflected light when obliquely incident. In the present embodiment, the former method is used, but the latter method can also be used. Such a method of spectrally detecting the wavelength of the reflected light is called a spectroscopic ellipsometry method. The light 4 a emitted from the light source 41 passes through a rotatable polarizer 42, so that the polarization plane (S-polarized light, P-polarized light) is adjusted and the phase is adjusted, and the light 4 a is incident on the uneven pattern 43. The light 4b reflected by the concave / convex pattern 43 is spatially wavelength-separated by the spectroscopic optical system 44 according to the wavelength. The separated light 4c is detected by the photodetector 45 in which photoelectric elements are arranged in an array, and the intensity ratio and phase difference of S-polarized light and P-polarized light for each wavelength are detected, and the information is sent to the computer 46. The computer 46 compares the information from the light detector 45 with library information described later to calculate the cross-sectional shape of the concave / convex pattern 43, and the calculation result is output from the computer 46 as the cross-sectional shape of the concave / convex pattern 43 as a measurement object. Is done. In the spectroscopic ellipsometry method, even if the resist film thickness and the resist pattern shape are different, the same intensity ratio / phase difference state may occur depending on the incident conditions of incident light (incident angle, wavelength of incident light, etc.). Therefore, measurement accuracy is also improved by detecting a change in reflected light under a plurality of incident conditions (irradiation with a plurality of incident angles or irradiation with incident light with a plurality of wavelengths).

  Next, a method for measuring the cross-sectional shape of the concavo-convex pattern 43 as a measurement object will be described with reference to FIG. First, as a preparatory stage before measurement, the assumed cross-sectional shape of the concavo-convex pattern 43 is defined on the computer 46 using an optical simulator of a vector diffraction model. The vector diffraction model is, for example, RCWA (Rigorous Coupled Wave Analysis), which is a model that solves an eigenvalue equation by representing an electric field in a periodic structure by Fourier transform. The calculator 46 obtains the state of the reflected light from each cross-sectional shape defined next by simulation calculation and holds the state value as a library. That is, the calculator 46 acquires the optical constants (refractive index n, absorption coefficient k, thickness d of each substance) of the substances constituting the concave / convex pattern 43 in step 1, and in step 2, the incident condition (wavelength λ or The light beam is incident on the concave / convex pattern 43 by changing the incident angle θ). Next, the computer 46 assumes various cross-sectional shapes of the concavo-convex pattern 43 in step 3, and information (intensity ratio change and level) obtained from reflected light when incident light is incident on the concavo-convex pattern 43 in step 4. Change in phase difference) is calculated. The computer 46 performs this series of calculations on various defined different cross-sectional shapes, and stores the obtained calculation results and the corresponding cross-sectional shapes in association with each other as a library. Here, the library refers to data associated with the cross-sectional shape or optical constant of the concave-convex pattern 43 corresponding to the light flux state obtained by simulation calculation based on optical constants and concave-convex patterns having various cross-sectional shapes, or Refers to the database. This stored library is information calculated by simulation showing the relationship between the variation in the intensity of reflected light with respect to the change in wavelength or incident angle and the shape of the concavo-convex pattern 43.

  The optical constants of the concavo-convex pattern used in step 1 differ depending on whether the incident angle θ or the incident light wavelength λ is used as the incident condition parameter. When the incident angle θ is changed using a single wavelength and measurement is performed using reflected light obtained for each incident angle θ, an optical constant for the single wavelength used for measurement is input to the computer 46. On the other hand, when the incident angle θ is fixed and the wavelength λ of the incident light is changed and the reflected light obtained for each wavelength λ is measured, the optical constant for each wavelength used for the measurement needs to be input to the computer 46. There is. Next, in step 5, using the measuring instrument 300, the incident light 4a is actually incident on the concave / convex pattern 43 as a measurement object, and in step 6, information on the reflected light 4b obtained (change in intensity ratio, level). Change in phase difference) is detected by the photodetector 45. In step 7, the computer 46 compares the information on the actual reflected light 4b from the library by comparing the light flux information of the library stored in the storage device with the information on the actual reflected light 4b obtained from the detected value. Is extracted. In step 8, the computer 46 determines the cross-sectional shape of the concave / convex pattern 43 associated with the light flux information among the cross-sectional shapes defined on the computer 46 as the actual cross-sectional shape of the concave / convex pattern 43. In the present embodiment, the measuring instrument 300 uses a spectroscopic ellipsometry method that changes the wavelength as an incident condition, and information of reflected light obtained for each wavelength λ is referred to as spectral characteristics.

  Next, a method for measuring the remaining film thickness of the resist will be described with reference to FIG. In step S100, the calculator 46 of the measuring instrument 300 obtains the measurement accuracy of the remaining film thickness RLT and the measurement accuracy of the pattern height HT while changing the polarization state of the incident light with respect to the uneven pattern 43 that is the measurement object. Here, the measurement accuracy will be described. The minimum CD resolution that can be measured by the measuring instrument 300 used in current optical lithography is ΔCD = 0.2 nm. First, an evaluation criterion as expressed by Formula 1, that is, a value S (= Σ) obtained by integrating the absolute value of the difference between the wavelengths of the two spectral characteristics I1 and I2 having a CD value difference of 0.2 nm in the wavelength region. | I2 (λ) −I1 (λ) |) is defined. Next, when the RLT is changed instead of the CD, an RLT difference (ΔRLT) that takes the same value as S is calculated in a plurality of polarization states. On the other hand, when only HT is changed, a difference in HT (ΔHT) that takes the same value as S is calculated in a plurality of polarization states. In the present specification, ΔRLT and ΔHT are defined as measurement accuracy in the polarization state. An example of the result of calculating the measurement accuracy is shown in FIG.

  The measurement by the measuring instrument 300 will be described with reference to FIG. The polarizer (polarizer) 42 converts the light from the light source 41 into linearly polarized light, and causes the converted linearly polarized light to enter the concavo-convex pattern 43. In addition, an analyzer (not shown) is present in front of the spectroscopic optical system 44, and transmits only a polarized light component having a predetermined polarization direction out of elliptically polarized light reflected by the uneven pattern 43. The predetermined polarization directions are, for example, 0 degree, 45 degrees, 90 degrees, and 135 degrees. The photodetector 45 receives the polarization component of a predetermined polarization direction transmitted by the analyzer. In FIG. 8, for example, 0 degree polarization means that the polarization direction of reflected light is 0 degree.

The inventor of the present application has found that there is a difference between the measurement accuracy of HT and the measurement accuracy of RLT depending on the measurement conditions. For example, when the four polarization states shown in FIG. 8 are compared, the following can be understood.
(1) In any polarization state, ΔRLT is smaller than ΔHT, that is, the measurement accuracy of RLT (remaining film thickness) is superior to the measurement accuracy of HT (pattern height).
(2) In the polarization state of 45 degrees, the difference between ΔHT and ΔRLT, that is, the difference between the measurement accuracy of RLT (remaining film thickness) and the measurement accuracy of HT (pattern height) is the largest.
(3) In the polarization state of 0 degree, ΔRLT is the smallest, that is, the measurement accuracy of RLT (remaining film thickness) is the best.

  The step of setting the first polarization state and the second polarization state for measuring RLT based on the difference between the measurement accuracy of HT and the measurement accuracy of RLT is S110. In S110, the computer 46 sets the first polarization state and the second polarization state in which the measurement accuracy of RLT (residual film thickness) and the measurement accuracy of HT (pattern height) satisfy the following conditions. In the first polarization state, RLT measurement accuracy (first accuracy) is superior to HT measurement accuracy (second accuracy), and RLT measurement accuracy (first accuracy) and HT measurement accuracy (second accuracy) Is a polarization state satisfying ΔRLT << ΔHT. In such a polarization state, since the measurement accuracy of HT is greatly inferior to the measurement accuracy of RLT, the same spectral characteristics are exhibited as long as the RLT value is the same even if the HT value is different. Therefore, RLT can be obtained from the measurement result in the first polarization state. In the second polarization state, the RLT measurement accuracy (third accuracy) is superior to the RLT measurement accuracy (first accuracy) in the first polarization state, but the RLT measurement accuracy (third accuracy) and the HT measurement accuracy. This is a polarization state in which the difference from (fourth accuracy) is smaller than the first polarization state. Since the difference between RLT and HT measurement accuracy is small in the second polarization state, the contribution of RLT and the contribution of HT cannot always be separated. Therefore, the RLT value cannot necessarily be uniquely determined from the measurement result of the second polarization state. However, the RLT value obtained from the measurement result in the second polarization state is selected from the RLT values obtained from the measurement result in the first polarization state, thereby obtaining a more accurate RLT value. I can do it. In the present embodiment, the 45-degree polarization state with the largest difference between ΔHT and ΔRLT corresponds to the first polarization state, and the 0-degree polarization state with the smallest ΔRLT corresponds to the second polarization state. The method for obtaining the two polarization states in step S110 has been described above.

  In S120, the intensity of the reflected light is measured by the measuring instrument 300 for each of the plurality of wavelengths of the reflected light using the reflected light in the first polarization state (first step). In S130, the computer 46 narrows down the RLT with the first accuracy based on the measurement result of S120 and the library information (second step). In the present embodiment, the first polarization state is a case of 45 degree polarization, and since HT is much less sensitive than the RLT in the 45 degree polarization state, it is possible to limit the RLT. explain. FIG. 9 shows the result of spectral characteristics simulated by a vector diffraction model optical simulator (for example, RCWA) in the case of 45 degree polarized light which is the first polarization state. In FIG. 8, in the case of 45 degree polarization, the difference between the RLT measurement accuracy (ΔRLT45) 0.35 and the HT measurement accuracy (ΔHT45) 1.9 is the largest. Using ΔRLT45 and ΔHT45 having the largest difference in measurement accuracy, the RLT value is changed to −2ΔRLT45, −ΔRLT45, 0, + ΔRLT45, and + 2ΔRLT45 in the order from FIG. 9A to FIG. 9E in terms of the difference from the nominal value. The calculation result of the intensity difference of the spectral characteristics is shown. The five graphs shown in each of FIGS. 9A to 9E show that when the RLT value is the same, the HT value is changed from the nominal value to −2ΔHT45, −ΔHT45, 0, + ΔHT45, and + 2ΔHT45. The calculation result is shown. Referring to FIG. 9, it can be seen that the change in HT is insensitive to the change in RLT in the wavelength range from 0.4 μm to a high wavelength range. Regardless of the value of HT, the value of RLT can be narrowed down to the vicinity of a certain RLT. Thus, it was found that using the measurement result of 45-degree polarized light may limit RLT without being affected by HT. As described above, the RLT value is narrowed down using the reflected light in the first polarization state.

  In S140, the intensity of each of the plurality of wavelengths of the reflected light is measured by the measuring instrument 300 using the reflected light in the second polarization state (third step). In S150, the computer 46 calculates the RLT with the third accuracy based on the measurement result in S140 and the library information. Referring to FIG. 8, the RLT measurement accuracy (ΔRLT0) in the case of 0-degree polarization in the second polarization state is 0.14 nm, which is the measurement accuracy in the case of 45-degree polarization in the first polarization state ( ΔRLT45) Excellent compared to 0.35 nm. FIG. 10A is a schematic diagram in which the horizontal axis is RLT and HT is a parameter with respect to the spectral characteristic result of 45 degree polarized light which is the first polarization state of FIG. Further, FIG. 10B is a schematic diagram in which the horizontal axis is RLT and HT is a parameter with respect to the spectral characteristic result measured with 0-degree polarized light that is the second polarization state. For the purpose of measuring RLT with high accuracy, it is desirable to use the measurement result of the polarization state with better measurement accuracy than RLT. In the present embodiment, as shown in FIG. 10A, the RLT value range is narrowed down to the region c from the measurement result of the first polarization state (45-degree polarization). However, since the measurement accuracy of 45-degree polarized RLT is 0.35 nm, RLT cannot be measured with higher accuracy.

  In device manufacturing, the measurement accuracy of RLT (residual film thickness) is required to be suppressed to 0.2 nm or less, and the required accuracy is not satisfied only from the measurement result of 45-degree polarized light that is the first polarization state. Therefore, in the present embodiment, measurement is performed using the reflected light in the second polarization state (0 degree polarization) in Step 140, and three RLT value candidates (in FIG. 10B) whose intensity difference shown in FIG. The RLT in the region c is selected from the three white circles of (5), and the RLT is determined (fifth step). That is, the RLT can be measured with high accuracy by using the measurement result of the second polarization state (0 degree polarization) with better measurement accuracy.

[Second Embodiment]
In the first embodiment, the RLT measurement of the resist is described as being performed inside the measuring instrument 300. However, the RLT measurement of the resist is not limited to being performed by the computer 46 inside the measuring instrument 300. For example, the control device 400 outside the measuring instrument 300 in FIG. 2 performs RLT measurement by exchanging necessary data from the measuring instrument 300 via the communication unit 500 and executing a predetermined program. May be.

[Third Embodiment]
The third embodiment is characterized in that the variation between shot areas in a wafer is calculated for each lot regarding the RLT of a resist. Specifically, the measuring instrument 300 measures the pattern shape in 16 shot areas as shown in FIG. 11, the computer 46 determines the RLT of the 16 shot area, and the variation of RLT in the 16 shot area is 3σ or the like. Evaluate with. It is possible to determine whether the RLT of the lot is stable based on variations in RLT. Further, the third embodiment is characterized in that the imprint apparatus 100 is controlled based on the variation of RLT.

  FIG. 12 is a diagram showing a flow when RLT measurement is performed for each lot. In S200, the wafer of the first lot is introduced into the imprint apparatus 100, and in S210, all wafers (for example, 25 sheets) in the lot are imprinted using the imprint apparatus 100. The imprint process includes alignment, resist coating, imprinting, curing, and releasing of each wafer. These processing elements included in the imprint process are performed by corresponding actuators. For example, the actuator for resist application is the dispenser head 30. In S230, the computer 46 inside the measuring instrument 300 measures RLT in a plurality of shot areas for a specific number of wafers in the lot. In S240, the computer 46 calculates and evaluates the variation between RLT shot areas (sixth step). If the variation exceeds a predetermined threshold value in S250, the recipe for the actuator of the imprint apparatus 100 is determined in S260. Change the condition (operating condition). In the third embodiment, the supply amount of resist (ultraviolet curable resin) is changed as a recipe to be changed. For a shot region having a large RLT, the CPU 40 (control unit) changes so as to reduce the resist supply amount. Conversely, for shot areas with a small RLT, the CPU 40 changes so as to increase the resist supply amount and adjusts so that variations between RLT shot areas are reduced. The control device 400 determines whether all lots have been completed in S270, and if not completed, introduces the next lot in S280 and performs imprint processing according to the recipe changed in S260.

  Note that the function of the control device 400 may be included in the imprint apparatus 100 (for example, the CPU 40), or may include the imprint apparatus 100, the control apparatus 400, and the communication unit 500 as an imprint apparatus. Further, the example in which the RLT variation among a plurality of shot regions is obtained and the imprint processing conditions (actuator operating conditions) are set so as to reduce the variation has been described above. However, the present invention is not limited to this, and RLT variation between a plurality of locations (plural regions) in a shot region may be obtained, and imprint processing conditions may be set so as to reduce the variation.

[Fourth Embodiment]
In the third embodiment, in S260, the resist supply amount in the imprint apparatus 100 is changed based on variations between RLT shot areas. In the fourth embodiment, the CPU 40 (control unit) controls the gap between the wafer 1 and the mold 10 based on variations between RLT shot areas. For example, the CPU 40 (control unit) may control the pressing force or pressing amount of the mold 10. Specifically, in S260, the CPU 40 (control unit) issues a control command to increase the pressing amount of the mold lifting / lowering actuator 15 with respect to the shot region having a large RLT. On the other hand, when the RLT is small, the CPU 40 (control unit) issues a control command to reduce the pressing amount of the mold lifting / lowering actuator 15 and adjusts so that variations in RLT are reduced. For the adjustment of RLT, the drive amount of Z of the actuator of fine movement stage 3 may be controlled or both may be controlled instead of controlling actuator 15 for raising / lowering mold.

[Fifth Embodiment]
So far, it has been described that the change in RLT and HT is equivalent in the resist pattern shape, and that HT is not limited and only RLT is limited in the first polarization state. However, HT can be said to be a value determined to some extent by the height (depth) of the template (mold) due to the nature of the imprint process, and it can be said that the value does not vary so much. Therefore, HT can be limited to some extent assuming that the variation of HT is in the vicinity of a value determined by the height of the template. That is, for example, in FIG. 5C, since the number of pattern height candidates can be limited to three or less, the RLT range can also be limited. Therefore, the RLT is measured with high accuracy within a more limited range. be able to.

[Product Manufacturing Method]
A method of manufacturing a device (semiconductor integrated circuit element, liquid crystal display element, etc.) as an article includes a step of transferring (forming) a pattern onto a substrate (substrate, glass plate, film substrate, etc.) using the above-described imprint apparatus. Including. Further, the method may include a step of etching the substrate to which the pattern has been transferred. When manufacturing other articles such as patterned media (recording media) and optical elements, other processing steps for processing the substrate to which the pattern has been transferred may be included instead of the etching step.

Claims (7)

A plurality of wavelengths of light are obliquely incident on the resist concavo-convex pattern formed on the substrate by the imprint apparatus with a constant incident angle, and the intensity of the reflected light from the concavo-convex pattern is measured for each of the plurality of wavelengths. A measurement method for measuring the thickness of the concave portion of the concave-convex pattern from information indicating the relationship between the intensity measured for each of the wavelengths and the shape of the concave-convex pattern and the measurement result,
The measurement accuracy related to the thickness of the concave portion measured using the reflected light in the first polarization state from the concave / convex pattern is defined as the first accuracy, and the concave / convex pattern measured using the reflected light in the first polarization state. The measurement accuracy regarding the thickness of the difference between the thickness of the convex portion and the thickness of the concave portion is the second accuracy, and the measurement accuracy regarding the thickness of the concave portion measured using the reflected light in the second polarization state from the concave / convex pattern Is the third accuracy, and the measurement accuracy related to the difference between the thickness of the convex portion and the thickness of the concave portion measured using the reflected light in the second polarization state is the fourth accuracy, The first accuracy is superior to the second accuracy but inferior to the third accuracy, and the difference between the first accuracy and the second accuracy is greater than the difference between the third accuracy and the fourth accuracy. Thus, the first polarization state and the second polarization state State is set,
A first step of measuring the intensity of reflected light in the first polarization state for each of the plurality of wavelengths;
A second step of obtaining the thickness of the concave portion with the first accuracy based on the measurement result in the first step and the information;
A third step of measuring the intensity of reflected light in the second polarization state for each of the plurality of wavelengths;
A fourth step of obtaining a plurality of thicknesses of the concave portion with the third accuracy based on the measurement result in the third step and the information;
A thickness within a range defined by the thickness obtained in the second step and the first accuracy is selected from the plurality of thicknesses obtained in the fourth step, and the concave portion is selected. A fifth step of obtaining a thickness;
A measuring method characterized by comprising.   The measurement method according to claim 1, wherein the information is calculated by simulation for each of a plurality of polarization states. A single wavelength of light is obliquely incident on the resist concavo-convex pattern formed on the substrate by the imprint apparatus with a plurality of incident angles, and the intensity of reflected light from the concavo-convex pattern is measured for each of the plurality of incident angles, A measurement method for measuring the thickness of the concave portion of the concave / convex pattern from information indicating the relationship between the intensity of the reflected light measured for each of a plurality of incident angles and the shape of the concave / convex pattern and the measurement result,
The measurement accuracy related to the thickness of the concave portion measured using the reflected light in the first polarization state from the concave / convex pattern is defined as the first accuracy, and the concave / convex pattern measured using the reflected light in the first polarization state. The measurement accuracy regarding the thickness of the difference between the thickness of the convex portion and the thickness of the concave portion is the second accuracy, and the measurement accuracy regarding the thickness of the concave portion measured using the reflected light in the second polarization state from the concave / convex pattern Is the third accuracy, and the measurement accuracy related to the difference between the thickness of the convex portion and the thickness of the concave portion measured using the reflected light in the second polarization state is the fourth accuracy, The first accuracy is superior to the second accuracy but inferior to the third accuracy, and the difference between the first accuracy and the second accuracy is greater than the difference between the third accuracy and the fourth accuracy. Thus, the first polarization state and the second polarization state State is set,
A first step of measuring the intensity of reflected light in the first polarization state for each of the plurality of incident angles;
A second step of obtaining the thickness of the concave portion with the first accuracy based on the measurement result in the first step and the information;
A third step of measuring the intensity of the reflected light in the second polarization state for each of the plurality of incident angles;
A fourth step of obtaining a plurality of thicknesses of the concave portion with the third accuracy based on the measurement result in the third step and the information;
A thickness within a range defined by the thickness obtained in the second step and the first accuracy is selected from the plurality of thicknesses obtained in the fourth step, and the concave portion is selected. A fifth step of obtaining a thickness;
A measuring method characterized by comprising.   The measurement method according to claim 3, wherein the information is calculated by simulation for each of a plurality of polarization states. The first to fifth steps are performed for each of the plurality of regions of the substrate,
5. The measurement method according to claim 1, further comprising a sixth step of obtaining a variation in thickness of the plurality of concave portions obtained for each of the plurality of regions. An imprint apparatus for performing an imprint process for forming a concavo-convex pattern of a resist on a substrate,
An actuator for performing an operation related to the imprint process;
Based on the variation obtained by the measurement method according to claim 5, a control unit that controls an operating condition of the actuator so that the variation is reduced;
An imprint apparatus comprising: Forming a resist uneven pattern on a substrate using the imprint apparatus according to claim 6;
Processing the substrate on which the pattern is formed in the step;
A method for producing an article comprising:

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