JP2014220290A - Device manufacturing method, evaluation method, and evaluation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To evaluate the working conditions of a pattern formed on a substrate efficiently by the working under some working conditions.SOLUTION: A device manufacturing method forms a pattern on the surface of a wafer (step 140) via a working step including the exposure step in an exposure device and a development step in a coater/developer, receives the light emitted from the surface of a wafer by illuminating the surface thereof (step 144), calculates the exposure conditions of the pattern on the basis of the received light (steps 148, 152), and determines the quality of exposure conditions of the pattern by comparing the exposure conditions of the pattern thus calculated with a non-defective product range map defining the quality of the exposure conditions of the pattern in the exposure step (step 154).

Description

  The present invention relates to a device manufacturing method including a step of forming a pattern on the surface of a substrate, and an evaluation technique for determining whether processing conditions or exposure conditions of the pattern formed on the surface of the substrate are good.

  In an exposure apparatus such as a scanning stepper or a stepper used in a lithography process for manufacturing a device (semiconductor device or the like), an exposure amount (so-called dose), a focus position (a substrate to be exposed with respect to an image plane of a projection optical system) A plurality of exposure conditions such as the exposure defocus amount) and the exposure wavelength must be managed with high accuracy. For this purpose, it is necessary to inspect the actual exposure conditions of the exposure apparatus with high accuracy by exposing the substrate with an exposure apparatus and using a pattern or the like formed on the exposed substrate.

  For example, as a conventional inspection method for the focus position of an exposure apparatus, a pattern for evaluation of a reticle is illuminated with illumination light whose chief ray is inclined, and an image of the pattern is displayed on a plurality of substrates while changing the height of the substrate on a stage. There is known a method of sequentially exposing each shot, measuring a lateral shift amount of a resist pattern obtained by development after exposure, and inspecting a focus position at the time of exposure of each shot from the measurement result (for example, Patent Documents) 1).

US Patent Application Publication No. 2002/0100012

In the conventional focus position inspection method, exposure and development processes are required for inspection, and thus the measurement time is long.
Further, in the conventional inspection method for the focus position, it is necessary to expose a dedicated evaluation pattern, and it is difficult to evaluate when an actual device pattern is exposed.
The aspect of the present invention has been made in view of such problems, and efficiently evaluates the processing conditions of a pattern formed on a substrate by processing under predetermined processing conditions (for example, exposure conditions). For the purpose.

  According to the first aspect of the present invention, the pattern is formed on the surface of the substrate through the processing step by the processing apparatus, the surface of the substrate is illuminated, and the light emitted from the surface of the substrate is received and received. Based on the light, the processing conditions of the pattern are calculated, the calculated processing conditions of the pattern are compared with data defining the quality of the processing conditions of the pattern in the processing step, and the quality of the processing conditions of the pattern is determined. A device manufacturing method is provided that includes determining.

  In addition, according to the second aspect, through the exposure process by the exposure apparatus, the surface of the substrate on which the pattern to be inspected is formed is illuminated, and the light emitted from the surface of the substrate is received and received. Based on the light, the exposure condition of the pattern is calculated, and the calculated exposure condition of the pattern is compared with data defining the quality of the exposure condition of the pattern in the exposure process, and the exposure condition of the pattern is determined An evaluation method is provided that includes determining.

  Further, according to the third aspect, the illumination unit that illuminates the surface of the substrate having a pattern formed on the surface through the processing step by the processing apparatus, and the detection unit that detects light emitted from the surface of the substrate, The processing condition of the pattern is calculated based on the light detected by the detection unit, the calculated processing condition is compared with the data defining the quality of the pattern processing condition in the processing step, and the processing condition of the pattern An evaluation device is provided that includes a calculation unit that determines whether the quality is good or bad.

  According to the aspect of the present invention, the processing condition or exposure condition of the pattern formed on the substrate by processing or exposure under a certain processing condition or exposure condition can be efficiently evaluated.

(A) is a figure which shows the whole structure of the evaluation apparatus which concerns on embodiment, (b) is a block diagram which shows a device manufacturing system. (A) is a figure which shows the evaluation apparatus by which the polarizing filter was inserted on the optical path, (b) is a top view which shows an example of the surface pattern of a semiconductor wafer, (c) is a top view which shows an example of a condition wafer is there. (A) is an enlarged perspective view showing the concavo-convex structure of the repeating pattern, and (b) is a diagram showing the relationship between the incident surface of the linearly polarized light and the periodic direction (or repeating direction) of the repeating pattern. It is a flowchart which shows an example of the method (evaluation condition extraction) which defines evaluation conditions. (A) is a plan view showing an example of a wafer, (b) is an enlarged view showing one shot, and (c) is an enlarged view showing an example of an arrangement of a plurality of setting areas in the shot. It is a figure which shows the image of the wafer imaged on the several diffraction conditions. (A) is a figure which shows several focus change curves, (b) is a figure which shows several dose change curves. (A) And (b) is a figure which shows the focus change curve and dose change curve which were measured on two diffraction conditions, respectively. (A) is a figure which shows the residual of a focus position, (b) is a figure which shows the difference of exposure amount. (A) And (b) is a figure which shows the dose change curve and focus change curve which were measured on two diffraction conditions, respectively. (A) is a figure which shows an example of distribution of the exposure amount of a wafer surface, (b) is a figure which shows an example of distribution of the focus value of a wafer surface. It is a flowchart which shows an example of the preparation method (condition setting) of a good quality range map. It is a figure which shows the 1st process window. It is a figure which shows the 2nd process window. The figure which shows a 3rd process window, (b) is an enlarged view which shows an example of the pattern of a 3rd evaluation point. (A) is a figure which shows an example of the non-defective range map of 1st Embodiment, (b) is a figure which shows an example of the non-defective range map of 2nd Embodiment. It is a flowchart which shows an example of the evaluation method of the exposure condition of a pattern. (A) is an enlarged cross-sectional view showing the main part of the wafer, (b) is an enlarged cross-sectional view showing the main part of the wafer in the post-process, (c) is an enlarged cross-sectional view showing the wafer in the post-process, and (d) is FIG. 4 is an enlarged cross-sectional view showing a part of a pattern formed on a wafer, (e) is a diagram showing two spacer change curves and their residuals, and (f) is a diagram showing two etching change curves and their differences. It is a flowchart which shows an example of evaluation condition extraction of 2nd Embodiment. It is a flowchart which shows an example of the evaluation method of the process conditions of the pattern in 2nd Embodiment. (A) is a figure which shows the structure of the evaluation apparatus of 3rd Embodiment, (b) is a figure which shows the exposure apparatus with which the evaluation apparatus is mounted | worn. It is a flowchart which shows an example of evaluation condition extraction of 3rd Embodiment. It is a flowchart which shows an example of the evaluation method of the exposure condition of the pattern in 3rd Embodiment. It is a flowchart which shows a semiconductor device manufacturing method.

[First Embodiment]
Hereinafter, a preferred first embodiment of the present invention will be described with reference to FIGS. FIG. 1A shows an evaluation apparatus 1 according to this embodiment, and FIG. 1B shows a device manufacturing system DMS according to this embodiment. 1B, a device manufacturing system DMS includes a thin film forming apparatus 700 that forms a thin film on a surface (hereinafter also referred to as a wafer surface) of a semiconductor wafer (hereinafter referred to as a wafer), and a resist (that is, a photosensitive film). Coater / developer 200 for applying and developing a conductive material), an exposure apparatus 100 for exposing a circuit pattern such as a semiconductor device on the wafer surface coated with a resist, and a pattern (structure) formed on the wafer surface after exposure and development ) Is used to evaluate the processing conditions (for example, the exposure conditions in the exposure apparatus 100) of this pattern. As the exposure apparatus 100, for example, an immersion scanning stepper (scanning projection exposure apparatus) disclosed in, for example, US Patent Application Publication No. 2007/242247 is used. Further, the device manufacturing system DMS includes an etching apparatus 300 for processing a developed wafer, a scanning electron microscope (SEM) 400 for inspecting a shape such as a line width and a height of a pattern formed on the wafer surface, A transfer system 500 for transferring wafers between apparatuses, and a host computer 600 for mediating control information between these apparatuses and determining the quality of processing conditions are provided.

  In FIG. 1A, the evaluation apparatus 1 includes a stage 5 that supports a substantially disk-shaped wafer 10, and the wafer 10 that is transported by the transport system 500 in FIG. It is placed and fixed, for example, by vacuum suction. Hereinafter, in a plane (that is, a horizontal plane) parallel to the upper surface of the stage 5 that is not inclined, the X axis is taken in a direction parallel to the plane of FIG. 1A and is perpendicular to the plane of FIG. A description will be given by taking the Y axis in the direction and the Z axis in the direction perpendicular to the plane including the X axis and the Y axis. 2B and 2C, which will be described later, in a plane parallel to the surface of the wafer 10 or the like, two orthogonal axes are taken as an X axis and a Y axis, and the plane includes these X axis and Y axis. The vertical axis is the Z axis. In FIG. 1A, the stage 5 has a first drive unit (not shown) that controls a rotation angle φ1 with a normal CA at the center of the upper surface of the stage 5 as a rotation axis, and the center of the upper surface of the stage 5, for example. As shown, the tilt angle that is the tilt angle of the stage 5 with the axis TA (hereinafter referred to as the tilt axis TA) perpendicular to the paper surface of FIG. 1A (parallel to the Y axis of FIG. 1A) as the rotation axis. It is supported by a base member (not shown) via a second drive unit (not shown) that controls φ2. The tilt angle φ2 is also the tilt angle of the wafer surface of the wafer 10. In the present embodiment, the normal of the wafer surface is parallel to the normal CA of the stage 5, and therefore the normal of the wafer surface is also referred to as the normal CA.

  The evaluation apparatus 1 further emits the illumination system 20 that irradiates the illumination light ILI as parallel light onto the surface of the wafer 10 held on the stage 5 (that is, the wafer surface), and the wafer surface that is irradiated with the illumination light ILI. A light receiving system 30 that collects light (regularly reflected light, diffracted light, etc.), an imaging device 35 that receives light collected by the light receiving system 30 and detects an image on the wafer surface, and an output from the imaging device 35. And an arithmetic unit 50 for processing an image signal and the like. The imaging device 35 includes an imaging lens 35a that forms an image on the wafer surface, and a two-dimensional imaging device 35b such as a CCD or a CMOS, and the imaging device 35b collectively captures an image of the entire surface of the wafer 10. To output an image signal. Based on the image signal of the wafer 10 input from the imaging device 35, the arithmetic unit 50 is a digital image of the wafer 10 (for example, signal intensity for each pixel, signal intensity obtained by averaging pixel signals for each shot, or pixel An image processing unit 40 that generates information on the signal intensity averaged for each region smaller than the shot), and arithmetic units 60a, 60b, and 60c that process the image information output from the image processing unit 40. The inspection unit 60, the control unit 80 that controls the operation of the image processing unit 40 and the inspection unit 60, the storage unit 85 that stores information about the image, and the like, and the evaluation result of the obtained processing conditions is output to the host computer 600. And a signal output unit 90. Note that the evaluation apparatus 1 sends the evaluation result of the processing conditions (exposure conditions) obtained to a control unit (not shown) such as the exposure apparatus 100 or the etching apparatus 300 via the host computer 600 or without the host computer 600. It may be output. The calculation unit 50 may be configured as a computer as a whole, and the inspection unit 60, the control unit 80, and the like may be functions on the software of the computer.

  In the evaluation apparatus 1, the illumination system 20 includes an illumination unit 21 that emits illumination light, and an illumination-side concave mirror 25 that reflects illumination light emitted from the illumination unit 21 toward the wafer surface as parallel light. The illumination unit 21 selects light of a predetermined wavelength (for example, different wavelengths λ1, λ2, λ3, etc.) from the light source unit 22 such as a metal halide lamp or a mercury lamp and light from the light source unit 22 according to a command from the control unit 80 The light control unit 23 adjusts the intensity, and the light guide fiber 24 that outputs the light selected by the light control unit 23 and adjusted in intensity from a predetermined emission surface to the illumination-side concave mirror 25. As an example, the wavelength λ1 is 248 nm, λ2 is 265 nm, and λ3 is 313 nm. In this case, since the exit surface of the light guide fiber 24 is disposed on the focal plane of the illumination-side concave mirror 25, the illumination light ILI reflected by the illumination-side concave mirror 25 is irradiated as a parallel light beam onto the wafer surface. The incident angle θ1 of the illumination light with respect to the wafer 10 can be adjusted by controlling the tilt angle φ2 of the stage 5 according to a command from the control unit 80. Here, the incident angle θ1 of the illumination light to the wafer 10 is an angle formed between the principal ray of the light reflected from the illumination-side concave mirror 25 and the normal line CA of the wafer surface.

  A polarizing filter 26 (hereinafter referred to as an illumination-side polarizing filter 26) is provided between the light guide fiber 24 and the illumination-side concave mirror 25 so that it can be inserted into and removed from the optical path of the light emitted from the light-guide fiber 24. ing. As an example, the illumination-side polarizing filter 26 is inserted into and removed from the optical path by a driving unit (not shown) such as a motor based on a command from the control unit 80. As shown in FIG. 1A, when the illumination side polarizing filter 26 is removed from the optical path of the light emitted from the light guide fiber 24, an inspection using the diffracted light ILD from the wafer 10 (hereinafter referred to as a diffraction inspection). Is performed). On the other hand, as shown in FIG. 2A, in the state where the illumination side polarizing filter 26 is inserted in the optical path, an inspection using polarized light (change in the polarization state due to structural birefringence in the present embodiment) (hereinafter referred to as polarization). Called inspection). Such a polarization inspection is also called a PER inspection in the sense of an inspection using a polarization extinction ratio (PER). The illumination-side polarizing filter 26 is, for example, a polarizing plate (linear polarizing plate) having a transmission axis. As shown in FIG. 2A, the surface on which light emitted from the exit surface of the light guide fiber 24 is incident ( (Hereinafter referred to as the incident surface) 26a. The illumination side polarizing filter 26 is rotatable about an axis passing through the center of the incident surface 26a and orthogonal to the incident surface 26a. As an example, the illumination-side polarizing filter 26 is rotated by a driving unit (not shown) such as a motor based on a command from the control unit 80.

  The light receiving system 30 has a light receiving side concave mirror 31 disposed so as to face the stage 5, and parallel light emitted from the wafer surface is condensed on the image pickup device 35 by the light receiving side concave mirror 31, and the image pickup element 35 b of the image pickup device 35 is collected. An image of the wafer 10 is formed on the imaging surface. Further, a polarizing filter 32 (hereinafter referred to as a light receiving side polarizing filter 32) is provided between the light receiving side concave mirror 31 and the imaging device 35 so as to be able to be inserted into and removed from the optical path of the light reflected by the light receiving side concave mirror 31. ing. As an example, the light receiving side polarizing filter 32 is inserted into and removed from the optical path by a driving unit (not shown) such as a motor based on a command from the control unit 80. As shown in FIG. 1A, the diffraction inspection is performed with the light-receiving side polarizing filter 32 taken out from the optical path. On the other hand, as shown in FIG. 2A, the polarization inspection is performed with the light-receiving side polarizing filter 32 inserted in the optical path. Similarly to the illumination side polarizing filter 26, the light receiving side polarizing filter 32 is, for example, a polarizing plate (linear polarizing plate) having a transmission axis, and is reflected by the light receiving side concave mirror 31, as shown in FIG. It has a surface on which light is incident (hereinafter referred to as an incident surface) 32a. The light-receiving side polarizing filter 32 can also rotate about an axis passing through the center of the incident surface 32a and orthogonal to the incident surface 32a. That is, the direction of the transmission axis of the light receiving side polarizing filter 32 can be set to an arbitrary direction. As an example, the light-receiving side polarizing filter 32 is rotated by a driving unit (not shown) such as a motor based on a command from the control unit 80. In the polarization inspection, the polarization direction of the light-receiving side polarizing filter 32 (that is, the direction of the transmission axis of the light-receiving side polarizing filter 32) is usually the polarization direction of the illumination-side polarizing filter 26 (that is, the direction of the transmission axis of the illumination-side polarizing filter 26). ) Is set to a crossed Nicols state orthogonal to.

  In accordance with an instruction from the control unit 80, the inspection unit 60, in this embodiment, the exposure unit 60 exposes the wafer 10 by processing a digital image of the wafer surface supplied from the image processing unit 40 as will be described later. 100 exposure amounts (so-called dose), focus position, exposure wavelength (center wavelength and / or half-value width), and a plurality of temperatures such as the temperature of the liquid between the projection optical system and the wafer when the exposure is performed by the immersion method. A predetermined exposure condition among the exposure conditions is evaluated. The evaluation result of the exposure condition is supplied to a control unit (not shown) in the exposure apparatus 100 as necessary, and the exposure apparatus 100 corrects the exposure condition (for example, correction of offset or variation) according to the evaluation result. It can be performed.

  A predetermined pattern is projected and exposed on the wafer 10 via the reticle by the exposure apparatus 100 through the reticle by the exposure apparatus 100. After development by the coater / developer 200, the wafer 10 is placed on the stage 5 of the evaluation apparatus 1 by the transport system 500. Be transported. At this time, the wafer 10 is subjected to a pattern formed on the wafer surface by an alignment mechanism (not shown), a mark (for example, a search alignment mark) formed on the wafer surface, or an outer edge portion (for example, a notch) of the wafer 10 during the transfer. Or an orientation flat) and the like are conveyed on the stage 5 in an aligned state. As shown in FIG. 2B, exposure target regions 11 having a reticle pattern as a unit are formed at predetermined intervals on the wafer surface by exposure by the exposure apparatus 100. Hereinafter, the region 11 to be exposed is referred to as a shot 11. For example, the plurality of shots 11 are arranged at predetermined intervals in two orthogonal directions (for example, the X direction and the Y direction). Some shots have only one reticle pattern exposed, while others have a plurality of reticle patterns connected and exposed. As an example, each shot 11 is repeatedly formed with a line pattern having a longitudinal direction in the Y-axis direction as a circuit pattern of the semiconductor device along the X-axis direction. Here, the line-shaped pattern repeatedly formed along the X-axis direction is referred to as a repeated pattern 12. The repeated pattern is not limited to a line pattern, and may be a hole pattern or the like. 2 may be a pattern made of a dielectric material such as a resist pattern or a pattern made of a metal. In addition, there may be a plurality of regions (so-called chips) that eventually become a single device after the exposure process in a shot, or a single shot may become a single chip. is there. Although one shot 11 often includes a plurality of chip areas, FIG. 2B shows that one chip area is included in one shot for easy understanding.

  In order to perform the diffraction inspection of the wafer surface using the evaluation apparatus 1 configured as described above, the control unit 80 reads recipe information (for example, inspection conditions and procedures) stored in the storage unit 85, and Perform the process. First, as shown in FIG. 1A, the illumination side polarizing filter 26 and the light receiving side polarizing filter 32 are taken out from the optical path, and the wafer 10 is transferred onto the stage 5 by the transfer system 500. Note that the wafer 10 is placed at a predetermined position on the stage 5 in a predetermined direction based on position information of the wafer 10 obtained by an alignment mechanism (not shown) during the conveyance.

  Next, the incident surface of the illumination light ILI on the wafer surface (that is, the XZ plane in FIG. 1A) coincides with the repeating direction of the repeated pattern 12 in each shot 11 (see FIG. 2B). In other words, the rotation angle φ1 of the stage 5 is adjusted so that the rotation angle φ1 of the stage 5 is perpendicular to the longitudinal direction of the line. Further, the pitch of the repeating pattern 12 is P, the wavelength of the illumination light ILI incident on the wafer 10 is λ, the incident angle of the illumination light ILI (the angle formed by the principal ray of the illumination light ILI and the normal CA of the wafer surface) is θ1, When the diffraction angle of the n-th order (n is an integer other than 0) diffracted light ILD emitted from the wafer surface (the angle formed by the diffracted light ILD and the normal CA of the wafer surface) is θ2, the following equation ( The tilt angle φ2 of the stage 5 is adjusted so as to satisfy 1).

P = n × λ / {sin (θ1) −sin (θ2)} (1)
Next, emission of illumination light ILI having a predetermined selected wavelength from the illumination unit 21 is started. As a result, the illumination light ILI emitted from the light guide fiber 24 is reflected by the illumination-side concave mirror 25 and is irradiated onto the wafer surface as parallel light. The diffracted light ILD diffracted on the wafer surface is condensed on the image pickup device 35 by the light receiving side concave mirror 31, and an image (diffraction image) of the entire surface of the wafer 10 is formed on the image pickup surface of the image pickup device 35. The imaging device 35 outputs an image signal of the image to the image processing unit 40, and the image processing unit 40 generates a digital image of the wafer surface and outputs information on the image to the inspection unit 60. In this case, by satisfying the condition of Expression (1), an image of the wafer surface by the diffracted light ILD is formed on the imaging surface.

  Then, the wavelength λ of the illumination light ILI and the tilt angle φ2 of the stage 5 (incident angle θ1 or rotation angle) when the level of the individual image signals of the digital image obtained from the image on the wafer is equal to or higher than a certain intensity on average. A combination of the folding angles θ2) is called one diffraction condition. A plurality of diffraction conditions are included in the recipe information. In practice, the tilt angle φ2 of the stage 5 may be adjusted so that the signal intensity based on the image of the corresponding part of the obtained digital image is equal to or higher than the predetermined signal intensity on average. Such a method of adjusting the tilt angle φ2 can also be called a diffraction condition search. In addition, the diffraction condition search may be performed by changing other arbitrary conditions that can be adjusted in the evaluation apparatus 1. In addition to the wavelength λ and the tilt φ 2, the rotation angle φ 1 of the stage 5 (that is, the wafer orientation) is determined. You may adjust it.

  Next, in the present embodiment, an example of a method for detecting light from the pattern on the wafer surface using the evaluation apparatus 1 and evaluating the exposure conditions of the exposure apparatus 100 used when forming the pattern will be described. . Further, since it is necessary to obtain evaluation conditions in advance for the evaluation, an example of a method for obtaining the evaluation conditions (hereinafter also referred to as evaluation condition determination) will be described with reference to the flowchart of FIG. Here, as an example, a wafer surface diffraction inspection is performed using the evaluation apparatus 1. Assume that the exposure amount and the focus position are evaluated among a plurality of exposure conditions of the exposure apparatus 100.

  First, in order to determine the evaluation conditions, in step 102 (preparation of a conditionally adjusted wafer) in FIG. 4, as shown in FIG. 5A, as an example, a scribe line region SL (chip in the dicing process in the device manufacturing process) A wafer 10a in which N shots SAn (n = 1 to N) (N is an integer of, for example, several tens to hundreds) is arranged across a region that is a boundary when separating them from each other is prepared. Then, the coater / developer 200 transports the resist-coated wafer 10a to the exposure apparatus 100 shown in FIG. 1B, and the exposure apparatus 100 shots the wafer 10a in the scanning direction at the time of, for example, scanning exposure (FIG. 2C). The exposure amount gradually changes between shots arranged in the longitudinal direction, in other words, the direction along the Y axis), and in the non-scanning direction orthogonal to the scanning direction (in the short side direction of the shot in FIG. 2C). Yes, in other words, a reticle for a device (not shown) that actually becomes a product in each shot SAn while changing the exposure conditions so that the focus position gradually changes between shots arranged in the direction along the X-axis). The pattern is sequentially exposed. That is, a shot SAn on which the same reticle pattern is exposed is formed on the wafer 10a. Thereafter, the exposed wafer 10a is developed by the coater / developer 200, and a wafer (hereinafter referred to as a conditioned wafer) in which a repeated pattern 12 (here, a resist pattern) is formed on each shot SAn under different exposure conditions. 10a) is created.

As shown in FIG. 2 (c), the conditioned wafer 10a is a so-called FEM wafer (Focus Exposure Matrix) in which an exposure amount and a focus position are shaken in a matrix to be exposed and developed to form a repeated pattern 12 on each shot 11. Wafer).
In the following, it is assumed that a defocus amount with respect to the optimum focus position (herein referred to as a focus value) is used as the focus position. With respect to the focus position, for example, the focus value is set in five steps of −60 nm, −30 nm, 0 nm, +30 nm, and +60 nm in increments of 30 nm. The focus value numbers 1 to 5 on the horizontal axis in FIG. 7A described later correspond to the five focus values (-60 to +60 nm). Note that the focus value can be set in a plurality of stages in increments of 50 nm, for example, and the focus value can be set in 17 stages of −200 nm to +200 nm in increments of 25 nm, for example.

  As an example, the exposure amount is 9 steps in increments of 1.5 mJ (10.0 mJ, 11.5 mJ, 13.0 mJ, 14.5 mJ, 16.0 mJ, 17.5 mJ, 19.0 mJ, 20.5 mJ, 22 .0mJ). Numbers 1 to 9 on the horizontal axis in FIG. 7B described later correspond to the nine levels of exposure (10.0 to 22.0 mJ). The optimum exposure amount required for the exposure of the pattern for an actual semiconductor device is about 5 mJ to 40 mJ depending on the pattern, and the exposure amount is about 0.5 mJ to 2.0 mJ with the optimum exposure amount of the pattern as a center. It is desirable to change at intervals.

  When the conditioned wafer 10a is created, the conditioned wafer 10a is transferred onto the stage 5 of the evaluation apparatus 1 in FIG. Then, the control unit 80 reads out a plurality of diffraction conditions from the recipe information in the storage unit 85. As a plurality of diffraction conditions, for example, the wavelength λ of the illumination light ILI is any one of the above λ1, λ2, and λ3 (for example, λ1 is 248 nm, λ2 is 265 nm, and λ3 is 313 nm), and the tilt angle φ2 of the stage 5 is Assume 15 (= 3 × 5) conditions that are any one of the five angles D1 to D5 that satisfy Expression (1). Here, a diffraction condition in which the wavelength λ is λn (n = 1 to 3) and the tilt angle φ2 is Dm (m = 1 to 5) is represented by (n−Dm) in FIGS. 7A and 7B. .

  The diffraction conditions are sequentially set to the conditions of n = 1 of the 15 conditions, m = 1 to 5, n = 2, m = 1 to 5, n = 3, and m = 1 to 5. Under the diffraction conditions, the illumination light ILI is irradiated onto the surface of the conditionally adjusted wafer 10a, and the imaging device 35 picks up an image of the diffracted light of the conditionally adjusted wafer 10a and outputs an image signal to the image processing unit 40 (step). 104). At this time, the diffraction condition may be obtained using a diffraction condition search. FIG. 6 shows an example of the signal intensity distribution of images A1 to A15 of the conditioned wafer 10a imaged under the 15 diffraction conditions ε (n−Dm).

  Next, based on the image signal of the conditioned wafer 10a input from the imaging device 35, the image processing unit 40 outputs a digital image of the entire surface of the conditioned wafer 10a with respect to each of a plurality of (here, 15) diffraction conditions. Generate. Then, with respect to the plurality of diffraction conditions, image sensors corresponding to the entire shot SAn (see FIG. 5B) excluding the scribe line area SL of the conditionally adjusted wafer 10a using the corresponding digital images. A signal intensity (hereinafter, shot average intensity) obtained by averaging the signal intensities of the pixels 35b is calculated, and the calculation result is output to the inspection unit 60 (step 106). The reason why the shot average intensity is calculated in this way is to suppress the influence of the aberration of the projection optical system of the exposure apparatus 100 and the like.

  And the 1st calculating part 60a of the test | inspection part 60 is exposure in exposure conditions from the shot average intensity | strength of each shot formed in the condition shaking wafer 10a obtained regarding each of the several diffraction conditions (epsilon) (n-Dm). The change characteristic of the average intensity when the amount is the same and the focus value changes in five steps is extracted as a focus change curve and stored in the storage unit 85 (step 108). FIG. 7A shows a plurality of (here, 15) focus change curves obtained under the diffraction condition ε (n−Dm) when the exposure amount is the optimum amount. 7A and 7B, the vertical axis represents the relative value of the shot average intensity, and the horizontal axis of FIG. 7A represents the first to fifth focus values (-100 to +100 nm).

  Further, the first calculation unit 60a changes the exposure amount in nine steps with the same focus value in the exposure condition from all shot average intensities obtained for each of the plurality of diffraction conditions ε (n−Dm). The change characteristic of the average signal strength at the time is extracted as a dose change curve and stored in the storage unit 85 (step 110). FIG. 7B shows a plurality of dose change curves obtained under the diffraction condition ε (n−Dm) when the focus value is 0 (that is, the optimum focus position). The horizontal axis of FIG.7 (b) is the exposure amount (10.0-22.0mJ) of a 1st step-a 9th step.

  After that, the first calculation unit 60a has the same tendency of the focus change curve from the plurality of diffraction conditions (for example, when the focus value increases, the shot average intensity corresponding to both diffraction conditions changes almost the same). The dose variation curve has a tendency to be reversed (for example, when the exposure amount increases, the shot average intensity corresponding to one diffraction condition increases and the shot average intensity corresponding to the other diffraction condition decreases). A first set of first and second diffraction conditions having a characteristic) is selected, and the two selected diffraction conditions are stored in the storage unit 85 (step 112). In the present embodiment, (1-D2) of (n = 1, m = 2) and (3-D3) of (n = 3, m = 3) are selected as such first and second diffraction conditions. To do. FIG. 8A shows two focus change curves B2 obtained under diffraction conditions ε (1-D2) and (3-D3) among the 15 focus change curves shown in FIG. FIG. 8B shows two dose changes obtained under the diffraction conditions ε (1-D2) and (3-D3) among the 15 change curves in FIG. 7B. Curves C2 and C13 are shown. It can be seen that the focus change curves B2 and B13 change with the same tendency, and the dose change curves C2 and C13 change with the opposite tendency.

  Then, the first calculation unit 60a gains the focus change curve B2 obtained under the first diffraction condition ε (1-D2) with a gain a (that is, a value by which the shot average intensity corresponding to each focus value is multiplied) and an offset. Focus obtained with curve B2A (see FIG. 9A) corrected with b (that is, a value added to the shot average intensity corresponding to each focus value) and the second diffraction condition ε (3-D3) The gain a and the offset b are determined so that the change curve B13 coincides, that is, the difference ΔB between the corrected curve B2A and the focus change curve B13 (hereinafter referred to as focus residual ΔB) is minimized. These gain a and offset b are stored in the storage unit 85 (step 114). Note that the vertical axis on the right side of FIG. 9A is the value of the focus residual ΔB. In this case, as an example, the values when the focus values of the focus change curves B2 and B13 are Fi (i = 1 to 5) are LB2 (Fi) and LB13 (Fi), and The gain a and the offset b may be determined so that the error that is the sum of squares of the differences is minimized. In the case of FIG. 8A, since the value of the curve B2 is larger than that of the curve B13, the gain a is smaller than 1. Integration in equation (2) is performed for focus values Fi (i = 1-5).

Error = Σ {LB13 (Fi) − (a · LB2 (Fi) + b)} ² (2)
The gain a and the offset b may be determined and stored for each reticle pattern to be exposed.
Next, the first calculation unit 60a corrects the dose change curve C2 obtained under the first diffraction condition ε (1-D2) in FIG. 9B with the gain a and the offset b calculated in step 114. A difference value (hereinafter referred to as a dose difference value) between the curve C2A (see FIG. 19B) and the dose change curve C13 obtained under the second diffraction condition ε (3-D3) is a function of the exposure amount. The represented curve (hereinafter referred to as a reference dose curve) SD1 is calculated, and the calculated reference dose curve SD1 of FIG. 9B is stored in the storage unit 85 (step 116). In addition, the vertical axis | shaft of the right side of FIG.9 (b) is a dose difference value.

  Next, the second calculation unit 60b of the inspection unit 60 has a tendency that the dose change curve has the same tendency (for example, when the exposure amount increases, the shot average intensities corresponding to both diffraction conditions are almost equal to each other from the plurality of diffraction conditions. (Same changing characteristics) and the tendency of the focus change curve to be reversed (for example, when the focus value increases, the shot average intensity corresponding to one diffraction condition and the shot average intensity corresponding to the other diffraction condition) The second set of first and second diffraction conditions having the characteristic that changes in a reciprocal manner is selected, and the two selected diffraction conditions are stored in the storage unit 85 (step 118). As such first and second diffraction conditions, (1-D3) of (n = 1, m = 3) and (1-D4) of (n = 1, m = 4) are selected. Images of the wafer 10a obtained under the two selected diffraction conditions are images A3 and A4 in FIG.

  FIG. 10A shows two dose change curves C2 obtained under the diffraction conditions ε (1-D3) and (1-D4) among the 15 dose change curves shown in FIG. 7B. FIG. 10 (b) shows two focus changes obtained under the diffraction conditions ε (1-D3) and (1-D4) among the 15 change curves in FIG. 7 (a). Curves B3 and B4 are shown. It can be seen that the dose change curves C2 and C4 change with the same tendency, and the focus change curves B3 and B4 change with the opposite tendency. In the range where the focus value is small, the absolute value of the negative slope of the focus change curve B3 is larger than the absolute value of the negative slope of the focus change curve B4. It becomes smaller than the slope of the curve B4, and the curves B3 and B4 can be regarded as changing in the opposite tendency.

  Then, the second calculation unit 60b gains the dose change curve C3 obtained under the first diffraction condition ε (1-D3) with a gain a (that is, a value by which the shot average intensity corresponding to each exposure amount is multiplied) and an offset. A curve (not shown) corrected with b (that is, a value added to the shot average intensity corresponding to each exposure amount) and a dose change curve C4 obtained under the second diffraction condition ε (1-D4) The gain a and the offset b are determined so as to match, that is, the sum of squares of the residual ΔC (hereinafter referred to as the dose residual ΔC) between the corrected curve and the dose change curve C4 is minimized. The gain a and the offset b are stored in the storage unit 85 (step 120). In addition, the vertical axis | shaft of the right side of Fig.10 (a) is the value of dose residual (DELTA) C.

  Next, the second calculation unit 60b corrects the focus change curve B3 obtained under the first diffraction condition ε (1-D3) in FIG. 10B with the gain a and the offset b calculated in Step 120. A curve (hereinafter referred to as a focus value function) representing a difference value (hereinafter referred to as a focus difference value) between a curve (not shown) and the focus change curve B4 obtained under the second diffraction condition ε (1-D4). (Referred to as a reference focus curve) SF1 is calculated, and the calculated reference focus curve SF1 is stored in the storage unit 85 (step 122). The vertical axis on the right side of FIG. 10B is the focus difference value. With the above operation, the determination of the evaluation conditions for obtaining the first set of two diffraction conditions and the second set of two diffraction conditions, which are the evaluation conditions used when evaluating the exposure conditions of the exposure apparatus 100, is completed. .

  Next, when the exposure condition is evaluated by the evaluation apparatus 1 for a wafer on which a pattern is formed by exposure by the exposure apparatus 100 in an actual device manufacturing process, the evaluated exposure amount is used as a criterion for pass / fail judgment. In addition, a map (hereinafter referred to as a non-defective product range map) indicating what range the focus position is in the pattern (wafer) is required. Therefore, an example of a method for creating the non-defective range map (hereinafter referred to as “conditioning”) will be described with reference to the flowchart of FIG. Usually, the non-defective range map is created by a manufacturer that designs a device or a manufacturer that manufactures a device (hereinafter collectively referred to as a device manufacturer). This condition setting operation is controlled by the host computer 600. Here, the pattern (or wafer) formed on the wafer surface through exposure is a non-defective product, for example, a product manufactured using the pattern (or wafer). For example, when the pattern is a resist pattern, the pattern is used as a mask. It shows that a product (for example, a semiconductor device) manufactured through a device manufacturing process including a wafer etching process operates normally without causing malfunction. In addition, even if a defective pattern is once formed on the wafer surface, a good pattern can be formed if a pattern re-correction process such as rework or repair is performed later. It may indicate that it is possible.

  First, in step 124 of FIG. 12, as in step 102 of FIG. 4, exposure is performed by oscillating the exposure amount and focus position in a matrix in the exposure apparatus 100, and development is performed by the coater / developer 200. A conditioned wafer 10a, which is a so-called FEM wafer in which a pattern 12 is repeatedly formed on the shot 11, is created. As the conditionally adjusted wafer 10a, the conditionally adjusted wafer 10a itself used for determining the evaluation conditions in FIG. 4 may be used. Thereafter, the conditioned wafer 10a is transferred to the etching apparatus 300, and the conditioned wafer 10a is etched by using the repetitive pattern 12 as a mask in the etching apparatus 300 to remove the resist (step 126). As a result, as shown in FIG. 3C, a concave / convex repeated pattern 12E in which convex portions 2AE and concave portions 2BE are arranged at a pitch P in the X direction is formed on each shot 11 of the conditioned wafer 10a. In the present embodiment, the pattern formed on the conditioned wafer 10a is an actual device pattern. Therefore, each shot SAn of the conditioned wafer 10a shown in FIG. In addition, various uneven patterns having a more complicated shape (see, for example, FIG. 13B) are also formed.

  Conditioned wafer 10a on which repetitive patterns 12E and the like are formed by etching in etching apparatus 300 is transferred to a scanning electron microscope (hereinafter referred to as SEM) 400. The SEM 400 first measures, for example, the line width of the repetitive pattern 12E in each shot SAn of the conditioned wafer 10a (for example, the width in the X direction of the convex portion 2AE, the width in the X direction of the concave portion 2BE, etc.) Data (hereinafter referred to as a dimension map) recorded by associating the SAn with the measurement value of the line width of the repetitive pattern 12E inside the shot is created, and information on the created dimension map is output to the host computer 600 ( Step 128). The repeated pattern 12E whose line width is measured is a pattern formed in a predetermined evaluation area MAE in the shot SAn in FIG. In addition, as the measurement value of the line width of the repeated pattern 12E, an average value of the line width measurement values of the repeated pattern 12E in a plurality of evaluation regions in the shot SAn may be used, or the repeated pattern 12E for each evaluation region. You may use the line width measured about several parts in. In this embodiment, as an example, as shown in FIG. 16, a dimension map WM1 in which the line width (nm) of the repeated pattern 12E measured in each shot SAn is recorded is obtained.

  Furthermore, the SEM 400 displays, for example, a first evaluation target pattern (not shown) formed in a first evaluation area (hereinafter referred to as an evaluation point) MA1 having a certain size in each shot SAn in FIG. (Step 130). As an example, the SEM 400 compares the shape of the first evaluation target pattern obtained by observation with the shape of the reference pattern stored in advance in the host computer 600 for each shot SAn (n = 1 to N). Thus, the quality of the shape of the first evaluation target pattern is determined. Then, a first evaluation point map EM1 (see FIG. 13) is created as data indicating whether the shape of the first evaluation target pattern in each shot SAn is good or defective. In the first evaluation point map EM1, the first evaluation target pattern in the shot SAn in the non-defective product region GSA1 to which the double diagonal lines are given is good, and the first evaluation target pattern of the good product region GSA1 is formed. The exposure amount and the focus value for forming a pattern having a good exposure amount and focus value. The first evaluation point map EM1 is output to the host computer 600. At this time, if the shape of the first evaluation target pattern is good, a product (for example, a semiconductor device) manufactured through a subsequent manufacturing process operates normally. Here, since the shape of the first evaluation target pattern depends on the exposure amount and the focus value, the range of the exposure amount and the focus value in which a finally manufactured product (for example, a semiconductor device) operates normally. Is determined as the non-defective region GSA1.

  Note that the evaluation point maps in FIG. 13A and FIG. 14, FIG. 15, and FIG. 16A described below (that is, a diagram showing a non-defective area among a plurality of shots SAn) are gradually exposed in the vertical direction. Changes, and the focus position gradually changes in the horizontal direction. In addition, in the evaluation point maps EM2 and EM3 shown in FIGS. 14A and 15A, the evaluation target pattern in the shot SAn in the non-defective product regions GSA2 and GSA3 that are double-hatched is good.

  Thereafter, it is determined whether or not the next evaluation point pattern is to be inspected (step 132). When the next evaluation point pattern is to be inspected, in step 133 the parameter k indicating the order of evaluation points (the current value is Add 1 to 1) and return to step 130. Then, the SEM 400 inspects a second evaluation target pattern (not shown) formed in the second evaluation point MA2 in each shot SAn. Then, a second evaluation point map EM2 (see FIG. 14) is created as data indicating whether the shape of the second evaluation target pattern in each shot SAn is good or bad, and the created map is output to the host computer 600. Is done. As an example, the process returns from step 132 to step 130 via step 133, and the SEM 400 inspects a third evaluation target pattern (not shown) formed in the third evaluation point MA3 in each shot SAn. I do. Then, a third evaluation point map EM3 (see FIG. 15) is created as data indicating whether the shape of the third evaluation target pattern MA3P in each shot SAn is good or bad, and the created map is sent to the host computer 600. Is output.

In step 132, when the inspection of all the evaluation point patterns to be inspected is completed, the operation proceeds to step 134.
In step 134, the host computer 600 calculates a logical product of the non-defective product areas GSA1, GSA2, and GSA3 in the three evaluation point maps EM1, EM2, and EM3. That is, as shown in FIG. 16 (a), the non-defective product region GSA with double diagonal lines in which the shots SAn in which all the patterns of the three evaluation point maps EM1, EM2, and EM3 are determined to be good are arranged. A non-defective product range map PW1 is created as data indicating. Further, in the host computer 600, the line width recorded in the dimension map WM1 within the non-defective region GSA is determined from an appropriate value (for example, a line width for a device finally manufactured through a manufacturing process to operate normally). By excluding the off-shots, the range of shots in which the line width of the pattern and the pattern of the three evaluation points MA1 to MA3 are finally good, that is, the range of shots in which the exposure amount and the focus value are appropriate (for convenience) Similarly, a map (also referred to as a non-defective product range map PW1 for convenience) is obtained.

The non-defective product range map PW1 represents the range of the exposure amount and the focus position where the repeated pattern of unevenness finally formed by the etching device 300 becomes favorable when the exposure amount and the focus position change in the exposure apparatus 100. . Therefore, the non-defective product range map PW1 is a so-called process indicating a two-dimensional range (good product range GSA) of the exposure amount and the focus position in the exposure apparatus 100 for improving the uneven pattern finally formed after etching. It is a window. In other words, the non-defective product range map PW1 is an exposure in which a product (for example, a semiconductor device or the like) finally manufactured through a predetermined manufacturing process using a repetitive pattern of unevenness formed by the etching apparatus 300 operates normally. This is data indicating the allowable range of the amount and the focus position. The non-defective product range map PW1 is registered in the database in the host computer 600 as one piece of identification data (that is, ID data) of the exposure apparatus 100 (step 136). This completes the condition setting.
Next, a first set of two diffraction conditions ε (1−1) obtained by the evaluation apparatus 1 by the above-described evaluation condition determination for a wafer on which a pattern is formed by exposure by the exposure apparatus 100 in an actual device manufacturing process. D2) and (3-D3), and a second set of two diffraction conditions ε (1-D3) and (1-D4) are used for diffraction inspection, and the non-defective product obtained from the inspection results and the above conditions An example of an operation for comparing the range map PW1 (that is, the process window) and determining the quality of the pattern formed on the wafer surface will be described with reference to the flowchart of FIG.

  First, in step 140 of FIG. 17, a wafer 10 having the same shot arrangement as that of FIG. 5A and serving as an actual product (for example, a semiconductor device) coated with a resist is transferred to the exposure apparatus 100 of FIG. The exposure apparatus 100 exposes a pattern of an actual product reticle (not shown) to each shot SAn (n = 1 to N) of the wafer 10 and develops the exposed wafer 10. The exposure conditions at this time are the optimum exposure amount (so-called best dose) determined according to the reticle for all shots, and the focus position is the optimum focus position (so-called best focus position). ).

  However, in practice, for example, for each shot SAn of the wafer 10 (for each shot SAn) due to the influence of slight illuminance unevenness in the non-scanning direction in the non-scanning direction, stage vibration, and the like in the slit-shaped illumination area during scanning exposure in the exposure apparatus 100. Since there is a possibility that the exposure amount and the focus position vary for each repeated pattern), the exposure amount and the focus position are evaluated. The wafer 10 after exposure and development is loaded onto the stage 5 of the evaluation apparatus 1 in FIG. 1A via an alignment mechanism (not shown) (step 142). Then, the control unit 80 reads out the first set of first and second diffraction conditions ε (1-D2) and (3-D3) determined by the above-described condition determination from the recipe information in the storage unit 85. The diffraction conditions are sequentially set to the first and second diffraction conditions, and the illumination light ILI is irradiated onto the surface of the wafer 10 under each diffraction condition. An image of the wafer surface based on the above is taken and an image signal is output to the image processing unit 40. Further, the control unit 80 reads out the second set of first and second diffraction conditions ε (1-D3) and (1-D4) determined by the above-described condition determination from the recipe information in the storage unit 85. The diffraction conditions are sequentially set to the first and second diffraction conditions, and the illumination light ILI is irradiated onto the surface of the wafer 10 under each diffraction condition. An image of the wafer surface based on the above is taken and an image signal is output to the image processing unit 40 (step 144).

  Next, the image processing unit 40 generates a digital image of the entire surface of the wafer 10 for each of the first set of first and second diffraction conditions based on the image signal of the wafer 10 input from the imaging device 35. . Then, with respect to the first and second diffraction conditions, the average signal intensity (average luminance) in all shots SAn of the wafer 10 is calculated using the corresponding digital images, and the calculation result is output to the inspection unit 60. To do. Here, let L1n and L2n be the average signal intensities obtained for the nth shot SAn under the first and second diffraction conditions (n = 1 to N), respectively. These average signal intensities include two values, a focus change curve and a dose change curve, respectively.

  Then, the third calculation unit 60c in the inspection unit 60 calculates the average signal intensity L1n obtained under the first diffraction condition ε (1-D2) for each shot SAn of the wafer 10 in the above step 114. The signal intensity difference Δn is calculated by subtracting the average signal intensity L2n obtained under the second diffraction condition ε (3-D3) from the signal intensity L1n ′ corrected with the obtained coefficient (gain a and offset b). The calculation result is stored in the storage unit 85 (step 146). From this difference Δn, components corresponding to the corrected focus change curves B2A and B13 in FIG. 9A are substantially removed, and the difference between the corrected dose change curves C2A and C13 in FIG. 9B is obtained. Only the corresponding component is almost left.

  Therefore, the third calculation unit 60c applies the signal intensity difference Δn to the reference dose curve SD1 of FIG. 9B stored in step 116 for every shot SAn of the wafer 10, The exposure amount Dn is calculated, and the calculation result is stored in the storage unit 85 (step 148). The component resulting from the focus position is removed from the exposure amount Dn calculated or estimated in this way.

  Further, the third calculation unit 60c in the inspection unit 60 is imaged under the second set of two diffraction conditions ε (1-D3) and (1-D4) for every shot SAn of the wafer 10. A difference in signal intensity obtained from the image of the wafer 10 (a difference between values corrected using the coefficients (gain a ′ and offset b ′) stored in step 120) Δn ′ is calculated (step 150). Then, the third calculation unit 60c of the inspection unit 60 calculates the difference Δn ′ of the signal intensity with respect to the reference focus curve SF1 of FIG. 10B stored in the above step 122 for every shot SAn of the wafer 10. By applying, the focus value Fn is calculated, and the calculation result is stored in the storage unit 85 (step 152). From the focus value Fn calculated or estimated in this way, a component due to the exposure amount is removed.

  In the next step 154, as an example, the control unit 80 of the evaluation apparatus 1 sends the exposure amount Dn and focus value Fn data (for each shot SAn of the wafer 10) to the host computer 600 via the signal output unit 90 ( That is, the evaluation data is output. In response to this, the host computer 600 uses the evaluation data sent from the evaluation apparatus 1 and the non-defective product range map PW1 (ie, process window) of FIG. 16 registered as the ID data of the exposure apparatus 100 in step 136. In comparison, it is determined whether or not the exposure amount and the focus value of each shot SAn of the wafer 10 enter the non-defective region GSA.

  For example, when the wafer 10 includes a shot SAn in which the exposure amount and the focus value do not enter the non-defective region GSA, the host computer 600 determines that the evaluated wafer 10 is out of the non-defective range. When it is determined that the wafer 10 is within the non-defective range (step 156), the operation proceeds to step 164, and the wafer 10 proceeds to the next process (for example, etching in the etching apparatus 300).

  On the other hand, when it is determined in step 156 that the wafer 10 is out of the non-defective range, the host computer 600 proceeds to step 158 as an example, and determines whether or not to inspect the wafer 10 with the SEM 400. As an example, when the ratio of the shot SAn in which the exposure amount and the focus value in the wafer 10 do not enter the non-defective region GSA is small, or when the deviation of the exposure amount and the focus value of the shot SAn made out of the non-defective product from the non-defective region GSA is small. Then, the wafer 10 is sent to the SEM 400 to inspect whether the line width and the evaluation target pattern are within the allowable range (step 160). If the wafer 10 is a good product as a result of the inspection (step 162), the process proceeds to step 164 (next process).

  If it is determined in step 158 that inspection by the SEM 400 is not performed, and if the wafer 10 is determined to be out of the non-defective range by the re-inspection by the SEM 400 in step 160 (step 162), the operation proceeds to step 166. As an example, the wafer 10 is reused (ie, reworked) after the resist is removed. In step 166, instead of reworking or in conjunction with reworking, an alarm may be issued from the host computer 600 to the control unit (not shown) of the exposure apparatus 100 that a wafer outside the non-defective range has occurred. In response to this, the exposure apparatus 100 corrects the width distribution in the scanning direction of the illumination area during scanning exposure, for example. This reduces errors in the exposure amount and the focus position (that is, errors from the optimal exposure amount and the optimal focus position) during subsequent exposure.

  Further, as an example, the evaluation of the pattern exposure conditions by the evaluation apparatus 1 in FIG. 17 is executed for all wafers that have been exposed by the exposure apparatus 100 and have been developed by the coater / developer 200. Also in this case, since the evaluation in the evaluation apparatus 1 is completed in a very short time, the throughput (productivity) of the device manufacturing process does not decrease. Further, by determining whether or not the wafer is within the non-defective range by comparing the exposure condition evaluation results and the non-defective range map PW1 for all the wafers, if the wafer is out of the non-defective range, Since it is possible to prevent the process from proceeding to the next process, the generation of defective products in the next process can be reduced, and as a result, the throughput can be improved.

  On the other hand, since the measurement time is long in the SEM 400, when the wafer pattern is inspected (evaluated) using the SEM 400, for example, the wafer pattern sampled at a predetermined ratio from the wafer that has been exposed and developed is used. It becomes the inspection object. For this reason, when there is a wafer that is out of the non-defective range among the wafers that have not been inspected, defective products are generated in the next process. Therefore, according to the evaluation method using the evaluation apparatus 1 of the present embodiment, it is possible to perform a complete inspection without reducing the throughput of the manufacturing process, and it is possible to reduce the occurrence of defective products in the next process. When the exposure condition is out of the allowable range, the exposure condition can be quickly improved by performing feedback to the exposure apparatus 100.

  As described above, the device manufacturing method of the present embodiment forms the repeated pattern 12 on the surface of the wafer 10 through a processing process including a lithography process including exposure in the exposure apparatus 100 and development in the coater / developer 200 (step) 140) Illuminate the surface of the wafer 10, receive the diffracted light emitted from the surface of the wafer 10 (step 144), and calculate the exposure conditions (exposure amount and focus position) of the repetitive pattern 12 based on the received light. (Steps 148 and 152), the calculated exposure condition of the repetitive pattern 12 is compared with a non-defective range map PW1 (process window) as data defining the quality of the exposure condition of the pattern in the exposure process. The quality of the exposure condition is determined (step 154).

  The evaluation method using the evaluation apparatus 1 of the present embodiment illuminates the surface of the wafer 10 on which the repeated pattern 12 to be inspected is formed on the surface through the exposure process by the exposure apparatus 100 and the development process by the coater / developer 200. Then, the light emitted from the surface of the wafer 10 is received (step 144), and the exposure condition of the repeated pattern 12 is calculated based on the received light (steps 148 and 152). Then, the quality of the exposure condition of the repetitive pattern 12 is determined by comparing with a good product range map that defines the quality of the exposure condition in the exposure process for forming the repetitive pattern 12 (step 154).

  According to this embodiment, by using the wafer 10 having the concave and convex repetitive pattern 12 provided by exposure under a plurality of exposure conditions as a plurality of processing conditions, the exposure amount among the plurality of exposure conditions In addition, the focus position can be evaluated with high accuracy while other influences are suppressed. In addition, there is no need to use a separate measurement pattern, and the exposure conditions can be evaluated by detecting light from the wafer on which the actual device pattern is formed. And can be evaluated with high accuracy.

  In the above-described embodiment, the host computer 600 (calculation unit) compares the evaluation result of the exposure amount and the focus position by the evaluation apparatus 1 on the wafer 10 in step 154 with the non-defective range map PW1. On the other hand, the inspection unit 60 of the calculation unit 50 of the evaluation apparatus 1 may perform comparison between the evaluation result of the exposure amount and the focus position regarding the wafer 10 and the non-defective product range map PW1. In this case, the non-defective product range map PW1 is supplied from the host computer 600 to the inspection unit 60 via the control unit 80 of the evaluation apparatus 1.

  As described above, when the evaluation apparatus 1 determines whether or not the wafer 10 is in the non-defective range, the evaluation apparatus 1 is subjected to processing steps including exposure by the exposure apparatus 100 and development by the coater / developer 200, so that the repeated pattern 12 is formed on the surface. An illumination system 20 that illuminates the surface of the formed wafer 10, a light receiving system 30 that detects light emitted from the surface of the wafer 10 and captures an image of the surface, an imaging unit 35 (detection unit), and an imaging unit The exposure condition (exposure amount and focus position) of the repetitive pattern 12 is calculated based on the image (detected light) imaged in 35, and the non-defective range that defines the calculated exposure condition and the quality of the exposure condition in the exposure process And a calculation unit 50 that compares the map PW1 and determines whether the exposure condition of the repeated pattern 12 is good or bad. The exposure condition determination result is supplied from the evaluation apparatus 1 to the exposure apparatus 100, and the exposure apparatus 100 corrects the exposure condition.

According to this evaluation apparatus 1, it is possible to efficiently and highly accurately evaluate exposure conditions relating to a pattern to be actually exposed.
Further, as in the present embodiment, when determining the quality of the wafer by comparing the evaluation result of the exposure amount and the focus position regarding the wafer with the two-dimensional good product range map PW1 (process window), the exposure amount and the focus position are determined. Compared with the case of determining pass / fail individually, the ratio of determining a defective product although it is a non-defective product is reduced, so that the throughput of device manufacturing can be further increased.
Conventionally, it has been assumed that a non-defective range map uniquely created by each evaluation apparatus is compared with the exposure conditions calculated by the evaluation apparatus. However, according to the present embodiment, it is possible to compare the non-defective range map (process window, that is, the reference for the non-defective range) created by the device manufacturer with the exposure condition calculated by the evaluation apparatus. As a result, it is possible to solve problems that have been missed conventionally and problems that have not been evaluated as defective if a process window is used.

  Note that the host computer 600 in this embodiment compares the evaluation result of the wafer exposure conditions (exposure amount and focus position) with the non-defective range map PW1, and when the exposure conditions are outside the non-defective range, the information is displayed. The exposure apparatus 100 is supplied as an example. However, the present invention is not limited to this method. For example, when the ratio of shot SAn in which the evaluated exposure amount and focus value do not enter the non-defective region GSA exceeds a predetermined ratio, A shot SAn that does not enter the non-defective area GSA may be notified to the exposure apparatus 100 as an evaluation result. Further, the host computer 600 informs the exposure apparatus 100 of deviation information from the optimum value of the average value of the exposure amount and deviation from the optimum value of the average value of the focus position with respect to the wafer determined to be out of the non-defective range, for example. You may supply. In this case, the exposure apparatus 100 can individually correct the exposure amount and / or the focus position according to the deviation.

  In the above-described embodiment, a calculation is performed to suppress the influence of one exposure condition on the average luminance obtained from the wafer image obtained under two diffraction conditions. In addition to this, for example, a calculation for suppressing the influence of one exposure condition is performed on three or more brightnesses obtained from an image of a wafer obtained under three or more diffraction conditions. The other exposure condition may be obtained.

  In the above embodiment, the first and second diffraction conditions are selected from the plurality of diffraction conditions. For example, the first and second diffraction conditions in which the focus change curve has the same tendency and the dose change curve has the opposite tendency are selected. And the selection of the second diffraction condition is easy. In addition to this, from a plurality of diffraction conditions, a difference (or a sum of squares of differences) with respect to a change in exposure amount rather than a difference (or a sum of squares of differences) of detection results under these conditions, for example. The first and second diffraction conditions may be selected so that becomes larger.

Further, in the above-described embodiment, the exposure amount and the focus position are evaluated as the exposure conditions. As the exposure conditions, the exposure light wavelength, the illumination conditions (for example, the coherence factor (σ value), the projection optical system, and the like in the exposure apparatus 100 are evaluated. The diffraction inspection of the above embodiment may be used to evaluate the numerical aperture of PL or the temperature of the liquid during immersion exposure.
In the present embodiment, in order to evaluate the two exposure conditions (exposure amount and focus position) as processing conditions independently from each other by the evaluation apparatus 1, for example, the first and second exposure conditions are respectively compared with the two exposure conditions. The diffraction conditions are obtained, and the measurement values obtained under these diffraction conditions are calculated. However, a method for evaluating two exposure conditions (or three or more exposure conditions) by the evaluation apparatus 1 is arbitrary. For example, as the first diffraction condition, the diffraction value in which the measured value changes substantially monotonously with respect to the change in the first exposure condition, and the measured value remains substantially constant with respect to the change in the second exposure condition. As the second diffraction condition, the measured value changes substantially monotonously with respect to the change in the second exposure condition, and the measured value remains substantially constant with respect to the change in the first exposure condition. A certain diffraction condition may be selected. In this case, since the first and second exposure conditions can be evaluated independently of each other only by taking an image of the wafer surface under two diffraction conditions, the inspection can be performed more efficiently.

  The evaluation apparatus 1 of the present embodiment is also regarded as an inspection apparatus that determines the exposure condition (processing condition) of the repeated pattern 12 (first pattern) exposed (processed) by the first exposure apparatus 100 (processing apparatus). be able to. This inspection apparatus includes a stage 5 that can hold a wafer 10 on which a repeated pattern 12 is formed, an illumination system 20 that illuminates the surface of the wafer 10 held on the stage 5 with illumination light ILI (detection light), An imaging device 35 and an image processing unit 40 (detection unit) that receive light emitted from the surface of the wafer 10 and detect a condition (amount of diffracted light) that defines the state of the light, and a repetitive pattern under known exposure conditions Based on the condition that defines the state of light detected by the detection unit with respect to the conditioned wafer 10a on which the wafer 12 is formed, exposure is performed from the condition that defines the state of light detected by the detection unit with respect to the wafer 10 to be inspected. And an arithmetic unit 50 for obtaining the exposure conditions of the apparatus 100.

  Then, a repetitive pattern 12E obtained by further processing the conditioned wafer 10a on which the repetitive pattern 12 is formed under known exposure conditions by the exposure apparatus 100 (first processing apparatus) by the etching apparatus 300 (second processing apparatus). Based on the inspection result of (second pattern), the exposure condition of the exposure apparatus 100 determined by the calculation unit 50 for the wafer 10 to be inspected is determined. According to the evaluation apparatus 1 as the inspection apparatus, since the quality of the exposure conditions in the exposure apparatus 100 can be determined based on the quality determination result of the repeated pattern 12E formed in the subsequent process, the wafer exposed by the exposure apparatus 100 Ten pass / fail judgments can be made in accordance with the post-process, and generation of defective products in the post-process can be suppressed.

In the present embodiment, the following modifications are possible.
First, the illumination side polarization filter 26 is arranged on the optical path so that the illumination light ILI becomes S-polarized light (linearly polarized light in a direction perpendicular to the incident surface) with respect to the wafer surface even during the diffraction inspection of the evaluation apparatus 1. It is also possible to do. In diffraction inspection using S-polarized light, the state of the uppermost layer can be detected without being affected by the underlayer of the wafer 10 (that is, the layer below the uppermost layer among a plurality of types of layers formed on the wafer 10).

  Usually, a reticle for an actual device is formed with a plurality of patterns having the same or orthogonal periodic directions at a plurality of pitches, and each shot SAn of the wafer 10 has a different pitch in addition to the repeating pattern 12 of the pitch P. This pattern is also formed. Furthermore, for example, when there is a pattern block in which a repetitive pattern of pitch P is arranged at a larger pitch P1 (> P), the same diffracted light as that generated from the pattern of pitch P1 is generated from this pattern block. It is also possible to perform a diffraction inspection on the assumption that there is a pattern with a pitch P1 substantially.

  In the above embodiment, the number of condition wafers 10a is one. However, when the number of shots with different combinations of exposure conditions obtained by multiplying the number of steps of the focus value by the number of steps of the exposure amount is larger than the number of shots on the entire surface of the conditionally adjusted wafer 10a, the conditionally adjusted wafer 10a is Multiple sheets may be created.

  Conversely, for example, when the number of shots SAn arranged in the scanning direction is larger than the number of steps of change in the focus value and / or when the number of arrangements in the non-scanning direction is larger than the number of steps of the exposure amount change, scanning is performed. Only a part of the shots arranged in the direction and / or the non-scanning direction may be exposed. However, in this case, even if a plurality of shots exposed by changing the focus value and the exposure amount are provided in the scanning direction or the non-scanning direction, the measurement values obtained for the shots having the same focus value and exposure amount may be averaged. Good. Further, for example, the influence of unevenness in resist coating between the center and the periphery of the wafer and the influence of the difference in the scanning direction of the wafer (+ Y direction or −Y direction in FIG. 2C) during scanning exposure are reduced. Therefore, a plurality of shots having different focus values and exposure amounts may be arranged at random.

  Further, in step 106, in order to further suppress the influence of the aberration of the projection optical system of the exposure apparatus 100, for example, the pixel of the image sensor 35b corresponding to the partial area CAn in the center of the shot SAn in FIG. An average signal intensity obtained by averaging the signal intensities of the signal may be calculated.

  However, the influence of the aberration of the projection optical system (error distribution given to the digital image) can be obtained in advance, and the influence of the aberration can be corrected at the stage of the digital image. In this case, instead of the shot average intensity, the average signal intensity is calculated for each setting area 16 (see FIG. 5C) such as a rectangle (I is an integer of several tens) in the shot SAn. For example, the subsequent processing may be performed using the signal intensity of the pixel of the image sensor 35b corresponding to the setting area 16 at the same position in the shot SAn. The arrangement of the setting areas 16 is, for example, 6 rows in the scanning direction and 5 columns in the non-scanning direction, but the size and arrangement are arbitrary.

In the above-described embodiment, the exposure conditions are evaluated using the curve information stored in the storage unit 95 as the dose change curve and the focus change curve. Instead of using the curve information as described above, the exposure condition may be evaluated using information such as a table corresponding to the dose change curve and the focus change curve.
In step 120 of the above embodiment, the curve obtained by correcting the focus change curve B12 obtained under the second diffraction condition ε (3-D3) with the gain a ′ and the offset b ′, and the first diffraction condition ε The gain a ′ and the offset b ′ may be determined so that the focus change curve B2 obtained in (1-D2) matches. Further, even if the curve B2A and the focus change curve B13 are approximated by a high-order polynomial (for example, a fourth-order polynomial) regarding the focus value Fi, the values of a and b are determined so that the square sum of these differences is minimized. Good. Alternatively, only the gain a or the offset b may be used to correct one focus change curve, and the value of a or b may be determined so that the corrected curve matches the other focus change curve as much as possible. . Further, for example, for each focus value Fi, the coefficient cfi to be multiplied by one focus change curve may be determined independently so that the corrected difference becomes zero.
Further, the reference dose curve SD1 may be approximated by a linear expression or a high-order polynomial relating to the exposure amount. Similarly, the reference focus curve SF1 may be approximated by a linear expression or a high-order polynomial regarding the focus value.

In step 128 of the above-described embodiment, the dimension map WM1 of FIG. 16A may be created using the evaluation result regarding the resist pattern instead of the pattern after etching.
In addition, the inspection of the evaluation area MAE in each shot SAn and the patterns in the evaluation points MA1 to MA3 by the SEM 400 in steps 128 and 130 may be sequentially performed for each shot. Further, the number of evaluation points MA1 to MA3 to be inspected is arbitrary, and there may be one evaluation point.

Further, in the above embodiment, in step 134, the non-defective product range is obtained from the dimension map WM1 indicating the line width of the pattern in the shot SAn and the three maps indicating the shot range in which the pattern of the evaluation points MA1 to MA3 is good. A map PW1 is created. In addition to this, the non-defective product range map PW1 may be created from only the dimension map WM1 without using three maps indicating shot ranges in which the patterns of the evaluation points MA1 to MA3 are good. In this case, in step 128, the SEM 400 measures the line width of the pattern in the evaluation region in each shot SAn of the wafer 10, and the dimension map WM1 is a map in which the average value of the line widths of the measurement results is assigned to each shot SAn. In step 134, a non-defective product range map PW1 is created as a non-defective product when the difference between the line width and the appropriate value (appropriate value of the line width) is smaller than an arbitrary threshold value. By creating the non-defective product range map PW1 from the dimension map WM1, the pattern shape evaluation (steps 130 to 133) of the evaluation points MA1 to MA3 can be omitted, so that simple conditions can be determined. In the creation of the dimension map WM1, it is preferable that the evaluation area for measuring the line width is a plurality of different areas in each shot SAn in terms of improving the reliability of the non-defective range map PW1.
Further, the non-defective range map PW1 may be created based on the result of the pattern shape evaluation of the evaluation points MA1 to MA3 without using the dimension map WM1. In this case, since the measurement of the line width of the pattern in the evaluation area MAE in the shot SAn and the creation of the dimension map WM1 (step 128) can be omitted, simple conditions can be determined.

The good product range map PW1 can also be created by a control unit (not shown) of the SEM 400. Further, the information on the non-defective range map PW1 may be transmitted from the host computer 600 to a control unit (not shown) of the exposure apparatus 100 and recorded in a storage device in the control unit.
In the above-described embodiment, the average signal intensity within the shot of all shots of the wafer 10 is calculated, and it is determined whether the shot is within the non-defective range. However, as another method, in steps 146 and 150, the average signal intensity is obtained for each of the I setting areas 16 (see FIG. 5C) in all shots SAn of the wafer 10, and in step 154, the shots SAn are obtained. You may evaluate whether it is in a non-defective range for every setting area 16 in it.

  In this case, FIG. 11A shows an example of the result obtained by converting the exposure amount Dni (the exposure amount of the i-th setting region 16) calculated for all the setting regions 16 of the wafer 10 into luminance in step 148. . Further, FIG. 11B shows an example of the result obtained by converting the focus value Fni calculated for all the setting areas 16 of the wafer 10 (the focus value of the i-th setting area 16) into luminance in step 152.

  In step 128 and step 130 of the above embodiment, the line width of the repetitive pattern and the shape of the pattern to be evaluated are evaluated by the SEM 400, but not limited to the SEM, a scatterometer, an atomic force microscope, etc. Existing measuring devices may be used.

In the above embodiment, the diffraction inspection is performed. In the above embodiment, it is also possible to perform the polarization inspection using polarized light (change in the polarization state due to structural birefringence in the repetitive pattern).
In the above embodiment, when the evaluation apparatus 1 performs only the diffraction inspection, the illumination-side polarizing filter 26 and the light-receiving-side polarizing filter 32 and a mechanism (drive) that inserts and removes them into the optical path of the illumination light or diffracted light. Part etc.) can be omitted.

[Second Embodiment]
A second embodiment will be described with reference to FIGS. Also in this embodiment, the device manufacturing system DMS in FIG. 1B is used, and the evaluation apparatus 1 in FIG. 1A is used to evaluate the processing conditions. In the present embodiment, the processing conditions of a wafer on which a repetitive pattern with a fine pitch is formed by a so-called spacer double patterning method (or sidewall double patterning method) are evaluated.

  Furthermore, in this embodiment, as will be described later, a polarization inspection (PER inspection) is performed as an example. Here, the case where the polarization inspection of the repetitive pattern 12 on the wafer surface in FIG. In this case, the repetitive pattern 12 on the wafer surface of FIG. 2B is along the arrangement direction (here, the X direction) in which the plurality of line portions 2A are short directions, as shown in FIG. It is assumed that the resist patterns (line patterns) are arranged at a constant pitch (period) P with the space portion 2B interposed therebetween. The arrangement direction (X direction) of the line portions 2A is also referred to as a periodic direction (or a repeating direction) of the repeating pattern 12.

Here, the design value of the line width D _A of the line portion 2A in the repetitive pattern 12 is set to ½ of the pitch P. Appropriate exposure conditions (i.e., exposure dose and focus position) if the repetitive pattern 12 is formed by, together with the line width D _B of the line width D _A and the space portion 2B of the line portion 2A are equal, side walls of the line portion 2A The part 2Aa is formed substantially perpendicular to the surface of the wafer 10, and the volume ratio of the line part 2A and the space part 2B is about 1: 1. Further, the shape of the XZ cross section of the line portion 2A at that time is a square or a rectangle. On the other hand, if the focus position in the exposure apparatus 100 when forming the repeated pattern 12 deviates from the proper focus position, the pitch P does not change, but the side wall portion 2Aa of the line portion 2A is in relation to the surface of the wafer 10. The shape of the XZ cross section of the line portion 2A is not a right angle but a trapezoid. Therefore, the volume ratio of the side wall portion linewidth D _A of 2Aa line portion 2A and the space portion 2B, D _B is becomes different from a design value, the line portion 2A and the space portion 2B of the line portion 2A approximately 1: deviates from 1 . On the other hand, when the exposure amount in the exposure apparatus 100 is changed, the pitch P and the line width D _A changes, the volume ratio of the line portion 2A and the space portion 2B is substantially 1: deviates from 1.

  In the polarization inspection, the change in the polarization state of the reflected light accompanying the change in the volume ratio between the line portion 2A and the space portion 2B in the repetitive pattern 12 (that is, the polarization of the reflected light due to the structural birefringence in the repetitive pattern 12). The change (state change) is used to inspect the state (good or bad) of the repeated pattern 12. In order to simplify the description, the ideal volume ratio (design value) is 1: 1. The change in the volume ratio is caused by a shift of the focus position from the appropriate value, and appears for each shot 11 of the wafer 10 and for each of a plurality of regions in the shot 11. The volume ratio can also be referred to as the area ratio of the cross-sectional shape.

  In order to perform the polarization inspection of the wafer surface using the evaluation apparatus 1 of the present embodiment, the control unit 80 reads recipe information (inspection conditions, procedures, etc.) stored in the storage unit 85 and performs the following processing. First, as shown in FIG. 2A, the illumination side polarizing filter 26 and the light receiving side polarizing filter 32 are inserted on the optical path. Then, the wafer 10 is transferred onto the stage 5 by the transfer system 500 of FIG. Note that the wafer 10 is placed at a predetermined position on the stage 5 in a predetermined direction based on position information of the wafer 10 obtained by an alignment mechanism (not shown) during the conveyance. When performing the polarization inspection, the tilt angle of the stage 5 is set so that the regular reflection light ILR from the wafer 10 can be received by the light receiving system 30, that is, the incident angle of the incident illumination light ILI (in FIG. 2A, the angle). The reflection angle (light receiving angle) of the light received by the light receiving system 30 with respect to the wafer surface is set to be equal to θ3). The reflection angle is an angle formed by the principal ray of the reflected light and the normal line CA of the wafer surface. Further, the rotation angle φ1 of the stage 5 is such that the periodic direction of the repetitive pattern 12 on the wafer surface is illumination light on the wafer surface as shown in FIG. 3B (in FIG. 3B, P-polarized linearly polarized light). It is set to incline at 45 degrees with respect to the vibration direction (L). This is because the signal intensity of the reflected light from the repeated pattern 12 is maximized.

  The illumination side polarizing filter 26 is disposed between the light guide fiber 24 and the illumination side concave mirror 25, and its transmission axis is set in a predetermined direction (direction). A polarized component (linearly polarized light) is extracted (transmitted) from the light. In the present embodiment, as an example, light emitted from the light guide fiber 24 becomes P-polarized linearly polarized light L (see FIG. 3B) via the illumination-side polarizing filter 26 and the illumination-side concave mirror 25, and the wafer surface. Is irradiated.

  At this time, since the illumination light ILI incident on the wafer surface (here, linearly polarized light L) is P-polarized light, as shown in FIG. When the angle is set to 45 degrees with respect to the traveling direction of the light L on the wafer surface, the angle formed by the vibration direction of the light L on the wafer surface and the periodic direction of the repeated pattern 12 is also set to 45 degrees. In other words, the linearly polarized light L is incident so as to obliquely cross the repetitive pattern 12 in a state where the vibration direction of the light L on the wafer surface is inclined 45 degrees with respect to the periodic direction of the repetitive pattern 12.

  The parallel specular light ILR reflected by the wafer surface is collected by the light receiving concave mirror 31 of the light receiving system 30 and reaches the image pickup surface of the image pickup device 35 via the light receiving side polarizing filter 32. At this time, the polarization state of the specularly reflected light ILR (here, linearly polarized light L) is changed to, for example, elliptically polarized light due to structural birefringence in the repeated pattern 12. The direction of the transmission axis of the light receiving side polarizing filter 32 is set so as to be orthogonal to the transmission axis of the illumination side polarizing filter 26 described above (in a crossed Nicols state). Therefore, the light receiving side polarization filter 32 extracts a polarized component having a vibration direction substantially perpendicular to the light L from the regular reflected light from the wafer 10 (repeated pattern 12) and guides it to the imaging device 35. As a result, on the image pickup surface of the image pickup device 35, the wafer surface is formed of a polarization component (the S polarization component if the light L is P-polarized light) whose oscillation direction is substantially perpendicular to the light L in the regular reflection light from the wafer 10. Is formed. If the minor axis direction of the elliptically polarized light is not orthogonal to the polarization direction of the light L, the transmission axis of the light receiving side polarizing filter 32 may be aligned with the minor axis direction of the elliptically polarized light. This may improve the detection sensitivity (the ratio of the change in the detection signal to the change in the exposure condition).

  Then, the imaging device 35 outputs an image signal of the image on the wafer surface to the image processing unit 40, and the image processing unit 40 generates a digital image of the wafer surface and outputs information on the image to the inspection unit 60. The inspection unit 60 evaluates the exposure conditions and the like in the exposure apparatus used when forming the repetitive pattern 12 of the wafer 10 using the image information. It is also possible to shift the polarization direction of the illumination light ILI incident on the wafer surface by rotating the illumination-side polarization filter 26 from the P-polarized light. However, even in this case, the polarization direction of the light receiving side polarizing filter 32 is set in a crossed Nicols state with respect to the illumination side polarizing filter 26. When such a digital image is generated, a combination of the wavelength λ of the illumination light ILI and the angle of the illumination side polarization filter 26 is referred to as one polarization condition. For example, it is possible to provide a mechanism for changing the incident angle θ3 (that is, the reflection angle θ3) of the illumination light ILI. When the incident angle is changed in this way, the incident angle is also included in one polarization condition. . A plurality of polarization conditions are included in the recipe information.

  Next, the spacer double patterning method will be described. In the spacer double patterning method, first, as shown in FIG. 18A, a resist is applied by a coater / developer 200 on the surface of, for example, the hard mask layer 17 of a wafer (wafer 10d), and a pattern is formed by an exposure apparatus 100. By the above exposure and development by the coater / developer 200, a repeated pattern 12 in which the line portions 2A of a plurality of resist patterns are arranged at a pitch P is formed. As an example, it is assumed that the pitch P is close to the resolution limit of the exposure apparatus 100. Thereafter, as shown in FIG. 18B, the line width of the line portion 2A is halved (half the width of the line portion 2A) by using etching (so-called slimming) by the etching apparatus 300. The thin film forming apparatus 700 deposits the spacer layer 18 so as to cover the line portion 12A. Thereafter, the spacer layer 18 of the wafer 10d is etched by a predetermined thickness by the etching apparatus 300, and then only the line portion 12A is removed by the etching apparatus 300, thereby making the hard mask layer 17 as shown in FIG. A repetitive pattern in which a plurality of spacer portions 18A having a line width of approximately P / 4 are arranged at a pitch P / 2 is formed thereon. Thereafter, by etching the hard mask layer 17 using the plurality of spacer portions 18A as a mask, as shown in FIG. 18D, the hard mask portions 17A having a line width of approximately P / 4 are arranged at a pitch P / 2. A repeated pattern 17B is formed. Thereafter, as an example, the repetitive pattern 17B is used as a mask to etch the device layer 10da of the wafer 10d, thereby forming a repetitive pattern having a pitch that is approximately ½ of the resolution limit of the exposure apparatus 100. Furthermore, it is also possible to form a repeated pattern with a pitch of P / 4 by repeating the above steps.

  For example, when performing a diffraction inspection using the evaluation apparatus 1, the pitch of the repeated pattern must be 1/2 or more of the wavelength λ of the illumination light ILI of the evaluation apparatus 1 in order for diffraction to occur. Therefore, when light having a wavelength of 248 nm is used as illumination light, the diffracted light ILD is not generated in the repetitive pattern 12 having a pitch P of 124 nm or less. For this reason, when the pitch P is close to the resolution limit of the exposure apparatus 100 as in the case of FIG. 18A, diffraction inspection becomes increasingly difficult. Further, as in the case of FIG. 18D, regarding the repetitive pattern 17B having a pitch of P / 2 (and further P / 4), only the regular reflection light ILR is generated, so that the diffraction inspection is difficult. However, when there is a pattern block in which the repeated patterns 17B are arranged at a larger pitch, diffraction inspection can be performed by detecting diffracted light from the pattern block.

  In the present embodiment, as shown in FIG. 18D, in order to evaluate the processing conditions of the repeated pattern 17B by detecting the light from the wafer 10d in which the repeated pattern 17B that does not generate diffracted light is formed in each shot. Then, the polarization inspection of the wafer surface is performed by the evaluation apparatus 1. Hereinafter, with reference to the flowchart of FIG. 19, description will be given regarding the determination of an evaluation condition for selecting a plurality of polarization conditions to be used when performing the polarization inspection, and with reference to the flowchart of FIG. 20, the selected polarization condition is used. A method for evaluating the processing conditions of the device manufacturing system DMS by performing polarization inspection will be described. 19 and 20, the steps corresponding to those in FIGS. 4 and 17 are denoted by the same or similar reference numerals, and the description thereof is omitted or simplified.

  Here, since the polarization inspection is performed on the surface of the wafer 10d on which the repeated pattern 17B having the pitch P / 2 is formed using the evaluation apparatus 1, as shown in FIG. The tilt angle φ2 of the stage 5 on which the polarizing filter 26 and the light receiving side polarizing filter 32 are inserted and the wafer 10d is placed receives the specularly reflected light ILR from the wafer 10d irradiated with the illumination light ILI from the illumination system 20. It is set so that light can be received by the system 30. Further, the rotation angle φ1 of the stage 5 is set so that the periodic direction of the repeated pattern 17B and the incident direction of the illumination light ILI intersect, for example, at 45 degrees. As a plurality of polarization conditions, for example, the wavelength λa of the illumination light ILI (any one of the above-described λ1 to λ3) and the angle θb (for example, rotation angle 36 degrees × b (b = 0) of the illumination-side polarization filter 26 are used. 15 polarization conditions η (λa, θb) (a = 1 to 3, b = 0 to 4) that are combinations with (4) to 4)) are assumed. However, when the angle of the illumination side polarizing filter 26 is switched, the angle of the light receiving side polarizing filter 32 is also switched so as to maintain a crossed Nicols state with respect to the illumination side polarizing filter 26. Furthermore, in the present embodiment, as processing conditions for the repeated pattern 17B by the device manufacturing system DMS, the spacer layer 18 deposition time ts (thin film deposition amount in the thin film forming apparatus 700) and the spacer layer 18 etching time in FIG. te (etching amount in the etching apparatus 300) is assumed, and the etching time te (hereinafter referred to as etching amount te) is evaluated while suppressing the influence of the deposition time ts (hereinafter referred to as spacer deposition amount ts). Shall.

  In order to determine the evaluation conditions, first, in step 102A of FIG. 19, the spacer double patterning process of FIGS. 18A to 18D is performed using five types of spacer deposition amounts ts (ts3 to ts7) and five types. The process is executed by 25 (= 5 × 5) processes in which the etching amounts te (te3 to te7) are combined, and the repeated pattern 17B is formed on each shot of 25 conditionally adjusted wafers (not shown). It is assumed that the deposition amount ts5 is the best deposition time (appropriate deposition amount) and the etching amount te5 is the best etching time (appropriate etching amount). In this case, the etching amounts te3 and te4 are insufficiently etched, and the etching amounts te6 and te7 are excessively etched.

  A plurality of (25 in this case) created conditionally adjusted wafers are sequentially transferred onto the stage 5 of the evaluation apparatus 1 in FIG. Then, in each of the plurality of conditionally adjusted wafers, the surface of the conditionally adjusted wafer is irradiated with the illumination light ILI under the plurality of (here, 15) polarization conditions η (λa, θb). An image of regular reflection light ILR from the condition-controlled wafer is picked up and an image signal is output to the image processing unit 40 (step 104A). Here, since 15 images are captured for each of the 25 conditionally adjusted wafers, a total of 375 (= 25 × 15) digital images are obtained in the image processing unit 40.

Further, the image processing unit 40 averages the signal intensity (average luminance) obtained by averaging the signal intensities of all the pixels in all the shots of the condition-controlled wafer using the corresponding digital images with respect to the plurality of polarization conditions. And the calculation result is output to the inspection unit 60 (step 106A).
Then, the first calculation unit 60a in the inspection unit 60 has the same etching amount te in the processing conditions from the average signal intensity of all the conditionally adjusted wafers obtained for each of the plurality of polarization conditions η (λa, θb). Then, the change characteristic of the average signal intensity when the spacer deposition amount ts changes in five stages is extracted as a spacer change curve (not shown) and stored in the storage unit 85 (step 108A). In addition, the first calculation unit 60a changes the etching amount in five steps from the average signal intensity obtained for each of the plurality of polarization conditions η (λa, θb) with the same spacer deposition amount in the processing conditions. The change characteristic of the average signal intensity at this time is extracted as an etching change curve (not shown) and stored in the storage unit 85 (step 110A).

  After that, the first calculation unit 60a has the same tendency that the spacer change curves tend to be the same (for example, when the spacer deposition amount ts increases, from the plurality of polarization conditions η (λa, θb)). And the etching change curve has a tendency to be reversed (for example, the characteristic that one average signal intensity substantially increases and the other average signal intensity decreases substantially when the etching amount te increases). The first and second polarization conditions of the set are selected, and the two selected polarization conditions are stored in the storage unit 85 (step 112A). FIG. 18 (e) shows two change curves Bk1 and Bk2 obtained under the first and second polarization conditions among the 15 spacer change curves. FIG. 18 (f) shows 15 change curves. Among the etching change curves, two change curves Ck1 and Ck2 obtained under the first and second polarization conditions are shown. The change curves Bk1 and Bk2 change with the same tendency, and the change curves Ck1 and Ck2 change with the opposite tendency.

  Then, the first calculation unit 60a includes a change curve (not shown) obtained by correcting the spacer change curve Bk1 obtained under the first polarization condition with the gain a (proportional coefficient or magnification) and the offset b, and the second polarization condition. The gain a and the offset b are determined such that the difference ΔBk between the corrected curve and the curve Bk2 is minimized by the method of least squares so that the spacer change curve Bk2 obtained in step S1 matches with the spacer change curve Bk2. And the offset b are stored in the storage unit 85 (step 114A). In addition, the vertical axis | shaft of the right side of FIG.18 (e) is the value of difference (DELTA) Bk.

  Next, the first calculation unit 60a includes a curve (not shown) obtained by correcting the etching change curve Ck1 obtained under the first polarization condition in FIG. 18F with the gain a and the offset b calculated in Step 114B. A curve (hereinafter referred to as a reference etching curve) SE1 in which a difference from the etching change curve Ck2 obtained under the second polarization condition is expressed as a function of the etching amount te is calculated, and the calculated reference etching curve SE1 is stored. This is stored in the unit 85 (step 116A). In addition, the vertical axis | shaft of the right side of FIG.18 (f) is the value of the reference | standard etching curve SE1.

  Further, the first calculation unit 60a has the same tendency of the etching change curve from the plurality of polarization conditions η (λa, θb) (for example, when the spacer deposition amount ts increases, both average signal intensities appear to be substantially the same. And a spacer change curve having a reverse tendency (for example, a characteristic in which one average signal intensity substantially increases and the other average signal intensity substantially decreases when the etching amount te increases). The first and second polarization conditions of the set are selected, and the two selected polarization conditions are stored in the storage unit 85 (step 118A).

  Then, the first calculation unit 60a uses the change curve obtained by correcting the etching change curve (not shown) obtained under the second set of first polarization conditions with the gain a ′ and the offset b ′, and the second polarization condition. The gain a ′ and the offset b ′ are determined so that the obtained etching change curve (not shown) matches, and the gain a ′ and the offset b ′ are stored in the storage unit 85 (step 120A). Next, the first calculator 60a corrects the spacer change curve (not shown) obtained under the second set of first polarization conditions with the gain a ′ and the offset b ′ calculated in step 120A, and A curve (hereinafter referred to as a reference spacer curve) SS1 in which the difference from the spacer change curve (not shown) obtained under the second polarization condition is expressed as a function of the spacer deposition amount ts is calculated (see FIG. 18E). ), The calculated reference spacer curve SS1 is stored in the storage unit 85 (step 122A). In addition, the vertical axis | shaft of the right side of FIG.18 (e) is also the value of reference | standard spacer curve SS1. With the above operation, the determination of the conditions for obtaining the first and second sets of polarization conditions, which are the evaluation conditions used when evaluating the processing conditions, is completed.

  Next, in the operation corresponding to the condition determination of FIG. 12 in the present embodiment, the above-described spacer double patterning process is performed in the step corresponding to step 124 of FIG. Each shot of 25 conditionally adjusted wafers (not shown) is executed by 25 (= 5 × 5) processes in which the amount ts (ts3 to ts7) and the five etching amounts te (te3 to te7) are combined. The repeating pattern 17B is formed respectively.

  In a step corresponding to step 128, the line width of the repetitive pattern 17B in the evaluation region in each shot of each wafer is measured by the SEM 400. As an example, the average value of the measured values of each shot is calculated as the line width of the wafer. As a measurement value, a dimension map (not shown) similar to the dimension map WM1 in FIG. In the dimension map in this case, as shown in FIG. 16B, for example, the horizontal direction is the etching amount te for each wafer, the vertical direction is the spacer deposition amount ts for each wafer, and the position of the nth wafer Wn. The measured value of the line width relating to the wafer is recorded in Further, in a step corresponding to step 130, the SEM 400 determines pass / fail of an evaluation target pattern (not shown) of the kth (k = 1, 2,...) Evaluation point in each shot of each wafer, and the kth evaluation. Create a point map. With respect to the evaluation point map EM1 in FIG. 13A, the k-th evaluation point map has a good evaluation target pattern in which the horizontal direction is the etching amount te for each wafer and the vertical direction is the spacer deposition amount ts for each wafer ( This shows the range of wafers that passed. Information of these dimension maps and k-th evaluation point map is output to the host computer 600 as an example.

  Thereafter, in a step corresponding to step 134, the host computer 600 takes the logical product of the non-defective areas of the plurality of kth evaluation point maps and further restricts the non-defective areas based on the dimension map. A non-defective range map PW2 shown in (b) is created. The non-defective product range map PW2 represents a two-dimensional range (non-defective product range) of the etching amount te and the spacer deposition amount ts when a wafer in which the formed pattern is good (passed) is processed. Therefore, the non-defective range map PW2 can also be regarded as a process window relating to the etching amount and the spacer deposition amount.

Thereafter, in the step corresponding to step 136, the created non-defective range map PW2 is registered in the database in the host computer 600 as ID data for identifying the etching apparatus 300 and the thin film forming apparatus 700, and the condition setting ends.
Next, by performing polarization inspection on the wafer 10d on which the repeated pattern 17B is formed by the device manufacturing system DMS in the actual device manufacturing process, the evaluation apparatus 1 performs polarization inspection, so that the spacer deposition amount and etching amount in the processing conditions are as follows. Evaluate like this. First, in step 140A of FIG. 20, the device manufacturing system DMS performs the spacer double patterning process described with reference to FIGS. 18A to 18D, thereby forming the repeated pattern 17B for each shot. The finished wafer 10d is manufactured. The processing conditions at this time are the best deposition time (appropriate amount) for the spacer deposition amount (deposition time ts) and the best etching amount (appropriate amount) for the etching amount (etching time te) in all shots. is there. However, in reality, the spacer deposition amount may vary due to uneven film thickness in the thin film forming apparatus 700, and the etching amount may vary due to etching unevenness in the etching apparatus 300.

The manufactured wafer 10d is loaded on the stage 5 of the evaluation apparatus 1 shown in FIG. 2A via an alignment mechanism (not shown) (step 142A). Then, the evaluation apparatus 1 captures an image of the wafer 10d and outputs an image signal to the image processing unit 40 under the first set and the second set of polarization conditions determined by the above evaluation condition determination ( Step 144A).
Next, the image processing unit 40 generates a digital image of the entire surface of the wafer 10d for each of the first set and the second set of polarization conditions. Then, the image processing unit 40 calculates the average signal intensity (average luminance) for every shot of the wafer 10d using the corresponding digital images with respect to the first set of first and second polarization conditions, The calculation result is output to the inspection unit 60. And the 3rd calculating part 60c in the test | inspection part 60 calculates the average signal intensity | strength obtained on the 1st polarization condition for every shot SAn (n = 1-N) of the wafer 10d by said step 114A. The average signal intensity obtained under the second polarization condition is subtracted from the signal intensity corrected with the obtained coefficients (gain a and offset b) to calculate an average signal intensity difference Δn, and the calculation result is stored in the storage unit 85. Store (step 146A). Thereafter, the third calculation unit 60c applies the difference Δn in the average signal intensity to the reference etching curve SE1 in FIG. 18 (f) stored in step 116A for every shot SAn of the wafer 10d. The etching amount En is calculated, and the calculation result is stored in the storage unit 85 (step 148A).

  Further, the image processing unit 40 calculates an average signal intensity (average luminance) for every shot of the wafer 10d using the corresponding digital images with respect to the second set of first and second polarization conditions, The calculation result is output to the inspection unit 60. Then, the third calculation unit 60c in the inspection unit 60 calculates the average luminance obtained under the first polarization condition for each shot SAn of the wafer 10d (the gain a ′ and the gain a ′). A difference Δn ′ of the average signal intensity is calculated by subtracting the average signal intensity obtained under the second polarization condition from the signal intensity corrected by the offset b ′), and the calculation result is stored in the storage unit 85 (step 150A). ). Thereafter, the third calculation unit 60c applies the difference Δn ′ in the average signal intensity to the reference spacer curve SS1 in FIG. 18E stored in step 122A for each shot SAn of the wafer 10d. The spacer deposition amount Sn to be calculated is calculated, and the calculation result is stored in the storage unit 85 (step 152A).

  In the next step 154A, as an example, the control unit 80 of the evaluation apparatus 1 sends data of the etching amount En and the spacer deposition amount Sn obtained for each shot of the wafer 10d to the host computer 600 via the signal output unit 90 ( (Evaluation data) is output. In response to this, the host computer 600 compares the evaluation data sent from the evaluation device 1 with the non-defective product range map PW2 (process window) (see FIG. 16B) registered as described above. Then, it is determined whether the etching amount En and the spacer deposition amount Sn of each shot of the wafer 10 enter the non-defective region.

  For example, when there is a shot in which the etching amount En and the spacer deposition amount Sn do not enter the non-defective region on the wafer 10d, or the ratio of the shot in which the etching amount En and the spacer deposition amount Sn does not enter the non-defective region exceeds a predetermined ratio. In this case, the host computer 600 determines that the evaluated wafer 10d is out of the non-defective range. When it is determined that the wafer 10d is within the non-defective range (step 156A), the operation proceeds to step 164A, and the wafer 10d proceeds to the next process (for example, the upper layer circuit pattern forming process).

  On the other hand, when it is determined that the wafer 10d is out of the non-defective range, the host computer 600 proceeds to step 158A as an example, and determines whether the wafer 10d is re-inspected by the SEM 400. When reinspecting, the wafer 10d is sent to the SEM 400 to reinspect whether the line width and the evaluation target pattern are within the allowable range (step 160A). If the wafer 10d is a non-defective product as a result of the re-inspection (step 162A), the process proceeds to step 164A (next process).

  If it is determined in step 158A that re-inspection by the SEM 400 is not performed, and if re-inspection by the SEM 400 in step 160A determines that the wafer 10d is out of the non-defective range (step 162A), the operation proceeds to step 166A. As an example, the host computer 600 issues an alarm to the controller (not shown) of the thin film forming apparatus 700 and the controller (not shown) of the etching apparatus 300 that a wafer outside the non-defective range has occurred. Accordingly, as an example, the thin film forming apparatus 700 corrects the spacer deposition amount (deposition time), and the etching apparatus 300 corrects the etching amount (etching time). As a result, during the subsequent execution of step 140A (spacer double patterning process), etching unevenness, spacer deposition unevenness, etc. are reduced, and the repeated pattern 17B can be manufactured with high accuracy.

  According to this embodiment, by performing polarization inspection under two sets of polarization conditions using the wafer 10d on which the repetitive pattern 17B for an actual device is formed, the etching apparatus 300 used when forming the pattern is used. It is possible to evaluate the etching amount and the spacer deposition amount in the thin film forming apparatus 700 with high accuracy by removing the influence of each other. Then, since this evaluation result is compared with the non-defective product range map PW2 to determine whether or not the processing conditions (etching amount and spacer deposition amount) of the wafer 10d are good, are the processing conditions of the wafer 10d good (passed)? Whether or not can be determined efficiently and with high accuracy. Then, by feeding back the determination result to the etching apparatus 300 and the thin film forming apparatus 700, generation of defective products in the subsequent processes can be suppressed.

  As described above, the device manufacturing method of the present embodiment forms the repeated pattern 17B on the surface of the wafer 10d through processing steps including thin film formation (spacer layer deposition) in the thin film forming apparatus 700 and etching in the etching apparatus 300. (Step 140A), illuminates the surface of the wafer 10d, receives the diffracted light emitted from the surface of the wafer 10d (Step 144A), and based on the received light, processing conditions (etching amount and spacer deposition) of the repeated pattern 17B Amount) (steps 148A and 152A), and the calculated processing condition of the repeated pattern 17B is compared with a non-defective product range map PW2 (process window) as data defining the quality of the pattern processing condition in the processing step. It is determined whether the processing conditions of the repeated pattern 17B are good or bad It is (step 154A).

  According to this embodiment, by using the wafer 10d having the concave and convex repeated pattern 17B provided by processing under a plurality of processing conditions, the etching amount and the spacer deposition amount among the plurality of processing conditions are set to each other. It can be evaluated with high accuracy while other influences are suppressed. In addition, there is no need to use a separate measurement pattern, and the processing conditions can be evaluated by detecting light from the wafer on which the actual device pattern is formed. And can be evaluated with high accuracy.

In the second embodiment, the following modifications are possible.
First, as processing conditions in the double patterning process, in addition to the deposition amount and etching amount of the spacer layer, the thickness (deposition amount) of the hard mask layer 17 and the etching amount when forming the line portion 12A ( The amount of slimming) may be inspected. Further, as processing conditions in the double patterning process, for example, an exposure amount and a focus position at the time of exposure in the exposure apparatus 100 can be considered.

  Also in the second embodiment described above, a method for evaluating two processing conditions (or three or more processing conditions) by the evaluation apparatus 1 is arbitrary. For example, for the first polarization condition, a condition is selected in which the measured value changes substantially monotonously with respect to the change in the first processing condition, and the measured value remains substantially constant with respect to the change in the second processing condition. As the second polarization condition, the measurement value changes substantially monotonously with respect to the change in the second processing condition, and the measurement value remains substantially constant with respect to the change in the first processing condition. And the image of the wafer may be taken under these two polarization conditions.

Further, in the second embodiment, in the evaluation condition for the polarization inspection (see FIG. 19), the wavelength λ of the illumination light ILI and the angle θ of the illumination side polarization filter 26 are set to the polarization condition η (λa, θb). As described above, the first polarization condition and the second polarization condition are selected by changing them, but it is not necessary to change the wavelength λ and the angle θ of the illumination side polarization filter 26. For example, in FIG. 2A, the angle of the light-receiving side polarizing filter 32 may be changed. Further, although the transmission axis of the illumination side polarizing filter 26 and the transmission axis of the light receiving side polarizing filter 32 are orthogonal to each other, both the transmission axes may not be orthogonal.

  In the second embodiment, in the polarization inspection, the angle formed by the periodic direction of the repeated pattern on the wafer surface with respect to the vibration direction of the linearly polarized illumination light on the wafer surface is set to 45 degrees. However, the detection sensitivity is obtained by setting the angle formed by the periodic direction of the repetitive pattern on the wafer surface to the vibration direction of the linearly polarized illumination light on the wafer surface to another angle such as 22.5 degrees or 67.5 degrees. When the (ratio of change in detection signal to change in exposure condition) increases, the angle may be changed. Note that the angle formed by the periodic direction of the repetitive pattern and the vibration direction of the illumination light is not limited to these and can be set to an arbitrary angle.

Further, in step 106A, in order to reduce the influence of the aberration of the projection optical system at the time of exposure, an average signal intensity (average luminance) obtained by averaging the signal intensities of the pixels in the central portion in all shots of the wafer is calculated. The calculation result may be output to the inspection unit 60.
In step 122A, the reference etching curve SE1 and the reference spacer curve SS1 may be approximated by a linear expression or a high-order polynomial for the etching amount te and the spacer deposition amount ts, respectively.

  In the second embodiment, the shape of the repeated pattern 17B is measured by the SEM 400, and the non-defective range map PW2 is created based on the measurement result. On the other hand, for example, the same process as in FIGS. 18B to 18D is further repeated for the repeated pattern 17B to form a repeated pattern having a pitch P / 4 that is 1/2 of the pitch P / 2 of the repeated pattern 17B. When forming, the shape of the repetitive pattern with the pitch P / 4 may be measured by the SEM 400, and the non-defective range map PW2 may be created based on the measurement result.

  In step 166A, even if the wafer 10d is out of the non-defective range, for example, when the average value of the spacer deposition amount is close to the optimum value and only the etching amount is deviated from the optimum value, the host computer 600 May issue an alarm only to the etching apparatus 300, and the etching apparatus 300 may correct the etching amount. On the contrary, when the average value of the etching amount is close to the optimum value and only the spacer deposition amount is deviated from the optimum value, the host computer 600 issues an alarm only to the thin film forming apparatus 700, and the thin film The forming apparatus 700 may correct the spacer deposition amount.

In the second embodiment, the processing conditions are evaluated using the information on the curves stored in the storage unit 95 as the etching change curve and the spacer change curve. Instead of using the curve information as described above, the processing conditions may be evaluated using information such as a table corresponding to the etching change curve and the spacer change curve, for example.
Further, the inspection of the evaluation area in each shot SAn and the pattern in the evaluation point by the SEM 400 may be sequentially performed for each shot. Further, the number of evaluation points to be inspected is arbitrary, and there may be one evaluation point. Further, the line width may be inspected without inspecting the evaluation point pattern.

  In the second embodiment, a dimension map (not shown) showing the line width of the pattern in the wafer Wn and a plurality of maps (not shown) showing shot ranges where the evaluation point pattern is good are shown. The non-defective range map PW2 is created. In addition to this, the SEM 400 measures the line width of the pattern in the evaluation region in each shot SAn of the wafer 10d, and a dimension map (not shown) is a map in which the average value of the line width of the measurement result is assigned to each wafer Wn. ) And the non-defective range map PW2 may be created from only the dimension map. In this case, it is desirable that the evaluation area for measuring the line width is a plurality of different areas in each shot SAn in terms of improving the reliability of the non-defective product range map PW2. Further, the non-defective range map PW2 may be created based on the result of the shape evaluation of the evaluation point pattern without using the dimension map.

The good product range map PW2 can also be created by a control unit (not shown) of the SEM 400. Further, the information of the non-defective range map PW2 may be transmitted from the host computer 600 to a control unit (not shown) of the exposure apparatus 100 and recorded in a storage device in the control unit.
In the above-described embodiment, the average signal intensity within the shot of all shots of the wafer 10d is calculated, and it is determined whether the shot is within the non-defective range. However, as another method, in steps 146A and 150A, the average signal strength is obtained for each of the I setting regions 16 (see FIG. 5C) in all shots SAn of the wafer 10d, and in step 154A, the shots SAn are obtained. You may evaluate whether it is in a non-defective range for every setting area 16 in it.
Moreover, although the polarization inspection is performed in the second embodiment, the diffraction inspection can also be performed in the second embodiment.
In the second embodiment, when the evaluation apparatus 1 performs only the polarization inspection, the illumination side polarization filter 26 and the light reception side polarization filter 32 are left installed in the optical path of illumination light or reflected light. May be. In this case, a mechanism (such as a drive unit) for inserting and removing the illumination side polarizing filter 26 and the light receiving side polarizing filter 32 in the optical path can be omitted.

  In the second embodiment, linearly polarized light obtained by converting light from the light source unit 22 into linearly polarized light by the illumination-side polarization filter 26 is illuminated to the wafer, but the light that illuminates the wafer is linearly polarized light. There is no need (see FIG. 2A). For example, the wafer may be illuminated with circularly polarized light. In this case, for example, by providing a half-wave plate in addition to the illumination-side polarizing filter 26, the light from the light source unit 22 is converted into circularly-polarized light by the illumination-side polarizing filter 26 and the half-wave plate, and the wafer. Illuminate to. Further, the wafer may be illuminated with elliptically polarized light other than circularly polarized light. A known configuration other than the above can be applied to the configuration for converting the light from the light source unit 22 into linearly polarized light or elliptically polarized light (elliptical polarized light including circularly polarized light). In addition to the light source that emits non-polarized light, such as a metal halide lamp or a mercury lamp, a light source that emits linearly polarized light or elliptically polarized light can also be used as the light source unit 22. In this case, the illumination side polarizing filter 26 can be omitted.

[Third Embodiment]
A third embodiment will be described with reference to FIGS. In FIGS. 21A and 21B, parts corresponding to those in FIG. 1A are denoted by the same reference numerals, and detailed description thereof is omitted. FIG. 21B shows an exposure apparatus 100A according to this embodiment. In FIG. 21B, an exposure apparatus 100A holds an illumination system ILS that illuminates the reticle R with exposure light and the reticle R as disclosed in, for example, US Patent Application Publication No. 2007/242247. A reticle stage RST that moves, a projection optical system PL that exposes the pattern of the reticle R onto the surface of the wafer 10, a wafer stage WST that holds and moves the wafer 10, and a drive mechanism (not shown) for the stages RST and WST And a local liquid immersion mechanism (not shown) for supplying a liquid between the projection optical system PL and the wafer 10 for liquid immersion exposure, and a main controller CONT for controlling the operation of the entire apparatus. Further, the exposure apparatus 100A of the present embodiment detects on-body evaluation of the pattern processing conditions (exposure conditions) by detecting regular reflection light or diffracted light from the pattern of the wafer 10 and performing diffraction inspection or polarization inspection. A device 1A is provided. As an example, the exposure apparatus 100A is incorporated in a device manufacturing system DMS instead of the exposure apparatus 100 and the evaluation apparatus 1 shown in FIG.

  FIG. 21A shows an evaluation apparatus 1A according to this embodiment. In FIG. 21A, the evaluation apparatus 1A holds a wafer 10 and moves it in at least a two-dimensional direction (a direction along the X axis and the Y axis orthogonal to each other), and a drive unit for the stage 5A 48, an illumination system 20A that illuminates a partial area (test area) of the surface (wafer surface) of the wafer 10 supported by the stage 5A with the illumination light ILI, and a wafer surface that has been irradiated with the illumination light ILI. A light receiving system 30A that receives the reflected light ILR (or diffracted light) and forms an image of the region under test, a CCD or CMOS type two-dimensional image sensor 47 that detects the image, and an output from the image sensor 47 And an arithmetic unit 50A that performs processing for processing the image signal to be processed. Based on the image signal of the wafer 10 input from the image sensor 47, the arithmetic unit 50A calculates the digital image of the wafer 10 (the signal intensity for each pixel, the signal intensity averaged for each shot, or the average for each area smaller than the shot. Image processing unit 40A for generating information on the signal strength and the like, an inspection unit 60A including a plurality of arithmetic units for processing image information output from the image processing unit 40A, and the image processing unit 40A and the inspection unit 60A. A control unit 80A for controlling the operation of the image forming apparatus, a storage unit 85A for storing information relating to the image, etc., and a signal output for outputting the evaluation result of the obtained processing conditions (ie, exposure conditions) to the main control unit CONT of the exposure apparatus 100A 90A. Note that the evaluation apparatus 1A may output the obtained processing condition evaluation results to the host computer 600 in FIG. In this embodiment, stage 5A is also used as wafer stage WST. In FIG. 21A, the Z axis is taken perpendicular to the plane including the X axis and the Y axis.

  The illumination system 20A includes an illumination unit 21 that emits illumination light, a light guide fiber 24 that guides illumination light emitted from the illumination unit 21, and an illumination lens that converts the illumination light emitted from the light guide fiber 24 into a parallel light flux. 42A, an illumination-side polarizing filter 26A for converting the illumination light into linearly polarized light, and a plane PA1 substantially conjugate with the pupil plane of the light receiving system 30A (a plane conjugate with the exit pupil of the objective lens 42B), and an opening 43Aa. The provided illumination-side aperture stop 43A, a drive unit 44A for moving the aperture stop 43A two-dimensionally in a plane perpendicular to the optical axis AXI of the illumination system 20A (in the YZ plane of FIG. 21A), and A beam splitter 45 that directs a part of the illumination light that has passed through the opening 43Aa toward the wafer 10, and an objective lens 42B that condenses the illumination light reflected by the beam splitter 45 in a region to be examined. To. It is also possible to omit the illumination side polarizing filter 26A and to change the beam splitter 45 to the polarizing beam splitter 45A. Further, when the diffraction inspection is performed by the evaluation apparatus 1A, the illumination side polarizing filter 26A is removed from the illumination optical path. For this reason, the drive part (not shown) for moving the illumination side polarizing filter 26A is provided.

  The light receiving system 30A is on a plane PA2 that is substantially conjugate with the objective lens 42B that receives the reflected light from the region to be examined of the wafer 10, the beam splitter 45, and the pupil plane of the light receiving system 30A (the exit pupil of the objective lens 42B). The light receiving side aperture stop 43B which is disposed and provided with the opening 43Ba, and the light receiving side aperture stop 43B are two-dimensionally in a plane perpendicular to the optical axis AXD of the light receiving system 30A (in the XY plane of FIG. 21A). The driving unit 44B to be moved, the light receiving side polarizing filter 32A disposed in the optical path of the light that has passed through the opening 43Ba, the driving unit 46 that rotates the light receiving side polarizing filter 32A, and the reflected light that has passed through the light receiving side polarizing filter 32A And an imaging lens 42 </ b> C that collects ILR (or diffracted light) and forms an image of the test region of the wafer 10 on the light receiving surface of the image sensor 47. As an example, the transmission axis of the illumination-side polarizing filter 26A is set so that the illumination light ILI is P-polarized with respect to the incident surface of the illumination light ILI incident on the wafer 10.

  When performing polarization inspection, the opening 43Ba of the light receiving side aperture stop 43B is symmetric with respect to the optical axis along the opening 43Aa of the illumination side aperture stop 43A so that the specularly reflected light ILR from the wafer 10 is received by the light receiving system 30A. (The position where the light reflected from the test region of the wafer 10 is transmitted by the illumination light from the illumination unit 21 that has passed through the opening 43Aa of the illumination-side aperture stop 43A). The light-receiving side polarizing filter 32A is installed on the illumination optical path. On the other hand, when performing a diffraction inspection, the opening 43Ba of the light-receiving side aperture stop 43B can receive the diffracted light of the detection target emitted from the surface (wafer surface) of the wafer 10 at a predetermined emission angle (diffraction angle). Set to Furthermore, the light-receiving side polarizing filter 32A is removed from the illumination optical path. For this reason, the drive unit 46 also has a mechanism for moving the light-receiving side polarizing filter 32A.

  The light receiving side polarizing filter 32A has a surface (hereinafter referred to as an incident surface) 32Aa on which a light ray enters. The driving unit 46 rotates the light-receiving side polarizing filter 32A around the axis (optical axis AXD) passing through the center of the incident surface 32Aa and parallel to the Z axis during the polarization inspection. Furthermore, the illumination-side polarizing filter 26A has a surface (hereinafter referred to as an incident surface) 26Aa on which light is incident. The evaluation apparatus 1A includes a drive unit (not shown) that rotates the illumination-side polarization filter 26A about an axis (optical axis AXI) that passes through the center of the incident surface 26Aa and is parallel to the X axis during the polarization inspection.

  Next, a case where the polarization inspection of the repeated pattern 12 of the wafer 10 is performed by the evaluation apparatus 1A will be described. In this case, the control unit 80A reads recipe information (inspection conditions, procedures, etc.) stored in the storage unit 85A, and performs the following processing. First, as shown in FIG. 21A, the illumination side polarizing filter 26A and the light receiving side polarizing filter 32A are inserted on the illumination optical path. Then, the wafer 10 is transferred onto the stage 5A via the alignment mechanism by a wafer loader system (not shown). Further, when performing the polarization inspection, as described above, the position of the opening 43Ba of the light receiving system aperture stop 43B is set to the opening of the illumination system aperture stop 43A so that the regular reflection light ILR from the wafer 10 can be received by the imaging lens 42C. It is set to be symmetric with respect to the position of 43Aa and the optical axis AXD. Further, the rotation angle of the stage 5A (or the rotation angle of the wafer 10 adjusted by the wafer loader system) is such that the periodic direction of the repetitive pattern 12 on the wafer surface is the illumination light on the wafer surface (see FIG. 3B). It is set to be inclined at 45 degrees with respect to the vibration direction of P-polarized linearly polarized light L in FIG. This is because the signal intensity of the reflected light from the repeated pattern 12 is maximized.

  The illumination side polarizing filter 26A is disposed between the light guide fiber 24 and the illumination system aperture stop 43A, and its transmission axis is set to a predetermined direction (direction), and from the illumination unit 21 according to the transmission axis. The polarization component (linearly polarized light) is extracted (transmitted) from the light. In the present embodiment, as an example, the light emitted from the light guide fiber 24 passes through the illumination-side polarizing filter 26A, the illumination system aperture stop 43A, the beam splitter 45, and the objective lens 42B. b)) and the wafer surface is irradiated.

  The specularly reflected light ILR of the parallel light reflected by the wafer surface enters the image sensor 47 via the objective lens 42B, the beam splitter 45, the light receiving system aperture stop 43B, and the imaging lens 42C of the light receiving system 30A. At this time, the direction of the transmission axis of the light receiving side polarizing filter 32A is set to be orthogonal to the transmission axis of the illumination side polarizing filter 26A described above (in a crossed Nicols state). Therefore, the polarization component having a vibration direction substantially perpendicular to the incident light is extracted from the specularly reflected light from the wafer 10 (repeated pattern 12) by the light receiving side polarizing filter 32A and guided to the image sensor 47. As a result, the imaging surface of the imaging device 47 has a wafer surface with a polarized light component whose vibration direction is substantially perpendicular to the incident light of the regular reflected light from the wafer 10 (S-polarized component if the light L is P-polarized light). Is formed.

  The image sensor 47 outputs an image signal of the image on the wafer surface to the image processing unit 40A, and the image processing unit 40A generates a digital image of the wafer surface and outputs information on the image to the inspection unit 60A. The inspection unit 60A evaluates the exposure conditions and the like in the exposure apparatus used when forming the repetitive pattern 12 of the wafer 10 using the image information. When a digital image is generated in such a manner, a combination of the wavelength λ of the illumination light ILI and the angle of the illumination side polarization filter 26A is referred to as one polarization condition.

  In the present embodiment, as an example, when the pitch of the repetitive pattern 12 is small and no diffracted light is generated, the light from the wafer 10 on which the repetitive pattern 12 is formed in each shot is detected, and the processing conditions for the repetitive pattern 12 are detected. In order to evaluate the above, a polarization inspection (PER inspection) of the wafer surface is performed by the evaluation apparatus 1A. Hereinafter, with reference to the flowchart of FIG. 22, description will be given on the evaluation condition selection for selecting a plurality of polarization conditions to be used when performing the polarization inspection, and with reference to the flowchart of FIG. 23, the selected polarization conditions are used. A method for evaluating the exposure conditions of the exposure apparatus 100A by performing polarization inspection will be described. 22 and 23, steps corresponding to those in FIGS. 19 and 20 are denoted by the same or similar reference numerals, and description thereof is omitted or simplified.

  Here, since the polarization inspection of the surface of the wafer 10 on which the repeated pattern 12 is formed is performed using the evaluation apparatus 1A, as shown in FIG. 21A, the illumination-side polarization filter 26A and the light receiving light are disposed in the optical path of the evaluation apparatus 1A. The side polarizing filter 32A is inserted, and the position of the opening 43Ba of the light receiving system aperture stop 43B is set so that the regular reflected light ILR from the wafer 10 irradiated with the illumination light ILI from the illumination system 20A can be received by the light receiving system 30A. Is done. The rotation angle of the stage 5A is set so that the periodic direction of the repeated pattern 12 and the incident direction of the illumination light ILI intersect, for example, at 45 degrees. As a plurality of polarization conditions, for example, the wavelength λa of the illumination light ILI (any one of the above λ1 to λ3) and the angle θb of the illumination side polarization filter 26A (for example, a rotation angle of 36 degrees × b (b = 0) 15 polarization conditions η (λa, θb) (a = 1 to 3, b = 0 to 4) that are combinations with (4) to 4)) are assumed. However, when the angle of the illumination side polarizing filter 26A is switched, the angle of the light receiving side polarizing filter 32A is also switched so as to maintain a crossed Nicols state with respect to the illumination side polarizing filter 26A. Furthermore, in this embodiment, it is assumed that the exposure amount and the focus position are evaluated among a plurality of exposure conditions of the exposure apparatus 100A.

  First, in order to determine the evaluation conditions, in step 102B of FIG. 22, exposure is performed by shifting the exposure amount (exposure amount or exposure energy) and the focus position in a matrix in the exposure apparatus 100A as shown in FIG. 2C. Then, development is performed to create a conditioned wafer 10a in which a pattern 12 is repeatedly formed on each shot 11 (SAn). Then, the illumination light ILI is irradiated onto the surface of the conditionally adjusted wafer 10a under the above-described (here, 15) polarization conditions η (λa, θb), and the imaging device 47 causes the specularly reflected light from the conditionally adjusted wafer. An image of a part of the wafer surface is captured by the ILR, and an image signal is output to the image processing unit 40A (step 104B). If an image of the entire surface of the wafer 10a is not obtained (step 170), the stage 5A is moved in the X direction and / or Y direction in step 172 to illuminate an area on the wafer surface that has not yet been imaged. It moves to the illumination area of the light ILI, returns to step 104B, and repeats steps 172 and 104B until an image of the entire surface of the wafer is obtained.

  After the image of the entire surface of the wafer is obtained, the image processing unit 40A uses the corresponding digital image for each of the plurality of polarization conditions to calculate the signal intensity of all the pixels in all the shots of the conditioned wafer. The averaged average signal intensity (average luminance) is calculated, and the calculation result is output to the inspection unit 60A (step 106B). Then, the first calculation unit in the inspection unit 60A has the same exposure amount and the focus value (from the average signal intensity of each shot of the conditionally adjusted wafer 10 obtained for each of the plurality of polarization conditions η (λa, θb). The change characteristic of the average signal intensity when the shift amount from the optimum value of the focus position changes in five steps is extracted as a focus change curve (not shown) and stored in the storage unit 85A (step 108B). In addition, the first calculation unit calculates an average signal when the focus value is the same and the exposure amount changes in, for example, nine levels, from all the average signal intensities obtained for each of the plurality of polarization conditions η (λa, θb). The intensity change characteristic is extracted as a dose change curve (not shown) and stored in the storage unit 85A (step 110B).

  Thereafter, the first calculation unit, from the plurality of polarization conditions η (λa, θb), has a first set of first and second sets in which the focus change curve has the same tendency and the dose change curve has the opposite tendency. The two polarization conditions are stored in the storage unit 85A (step 112B). The first calculation unit obtains the change curve (not shown) obtained by correcting the focus change curve obtained under the first polarization condition with the gain a (proportional coefficient or magnification) and the offset b, and the second polarization condition. The gain a and the offset b are determined so that the obtained focus change curve matches, and the gain a and the offset b are stored in the storage unit 85A (step 114B).

  Next, the first calculation unit 60a corrects the dose change curve obtained under the first polarization condition with the gain a and the offset b calculated in step 114B, and the dose obtained under the second polarization condition. A curve (hereinafter referred to as a reference dose curve) (not shown) representing the difference from the change curve as a function of the exposure dose is calculated, and the calculated reference dose curve is stored in the storage unit 85A (step 116B).

Further, the first calculation unit of the inspection unit 60A has a second set of second sets in which the dose change curve has the same tendency and the focus change curve has the opposite tendency from the plurality of polarization conditions η (λa, θb). The first and second polarization conditions are selected, and the two selected polarization conditions are stored in the storage unit 85A (step 118A).
Then, the first calculation unit obtains the dose change curve (not shown) obtained under the second set of first polarization conditions with the gain a ′ and the offset b ′ and the second polarization condition. The gain a ′ and the offset b ′ are determined so that the dose change curve (not shown) matches, and the gain a ′ and the offset b ′ are stored in the storage unit 85A (step 120B). Next, the first arithmetic unit corrects the focus change curve (not shown) obtained under the second set of first polarization conditions with the gain a ′ and the offset b ′ calculated in step 120B, A curve representing the difference from the focus change curve (not shown) obtained under the polarization condition (2) as a function of the focus value (hereinafter referred to as a reference focus curve) (not shown) is calculated, and the calculated reference focus curve Is stored in the storage unit 85A (step 122B). With the above operation, the determination of the conditions for obtaining the first and second sets of polarization conditions, which are the evaluation conditions used when evaluating the exposure conditions, is completed.

  Next, the repetitive pattern 12 formed on the conditioned wafer 10a in the present embodiment is a pattern (however, the pitch is small) that is the object of evaluation in the first embodiment. For this reason, the non-defective product range map PW1 of FIG. 16A created by the same method as the condition determination of FIG. 12 of the first embodiment is used as a non-defective range map as a reference for comparison with the evaluation result by the evaluation apparatus 1A. it can. The created non-defective range map PW1 is registered in the database in the host computer 600 as ID data for identifying the exposure apparatus 100A, and the condition setting ends.

  Next, in the actual device manufacturing process, the wafer 10 on which the repeated pattern 12 is formed by the device manufacturing system DMS (exposure apparatus 100A and coater / developer 200) is subjected to polarization inspection by the evaluation apparatus 1A, thereby exposing the wafer 10. The exposure amount and focus position in the exposure conditions of the apparatus 100A are evaluated as follows. First, in step 140B of FIG. 23, the wafer 10 for actual exposure having the same shot arrangement as that of FIG. 5A and coated with a resist is transferred to the exposure apparatus 100A of FIG. 21B. The pattern of the reticle R for an actual device is exposed to each shot SAn (n = 1 to N) of the wafer 10, and the exposed wafer 10 is developed. The exposure conditions at this time are the optimum exposure amount (best dose) determined in accordance with the reticle for the exposure amount in all shots, and the best focus position for the focus position. However, in actuality, the exposure amount and the focus position for each shot SAn of the wafer 10 due to, for example, slight illuminance unevenness in the non-scanning direction and vibration of the stage in the slit-like illumination area at the time of scanning exposure in the exposure apparatus 100A. Therefore, the exposure amount and the focus position are evaluated. The wafer 10 after exposure and development is loaded onto the stage 5 (wafer stage WST) of the evaluation apparatus 1A of FIG. 21A via an alignment mechanism (not shown) (step 142B).

  Then, in the evaluation apparatus 1A, a part of the wafer 10d is captured under the first and second polarization conditions determined by the above-described evaluation condition determination, and an image signal is sent to the image processing unit 40A. Output (step 144B). If an image of the entire surface of the wafer 10 is not obtained (step 170A), the stage 5A is moved in the X direction and / or Y direction in step 172A to illuminate an area on the wafer surface that has not yet been imaged. Moving to the illumination area of the light ILI, the process returns to step 144B, and steps 172A and 144B are repeated until an image of the entire surface of the wafer is obtained. It should be noted that the operations of steps 144B and 172A may be performed so as to repeat the imaging of the wafer surface image and the movement of the stage 5A (step movement) until an image of the entire surface of the wafer is obtained, for example, under each polarization condition. Good.

  After the image of the entire surface of the wafer is obtained, the image processing unit 40A generates a digital image of the entire surface of the wafer 10 for each of the first set and the second set of polarization conditions. Then, the image processing unit 40A uses the corresponding digital images with respect to the first and second polarization conditions of the first set, and calculates an average signal for every shot SAn of the wafer 10 (see FIG. 5A). The intensity (average luminance) is calculated, and the calculation result is output to the inspection unit 60A. Then, the third calculation unit in the inspection unit 60A uses the coefficient (gain a and offset) calculated in step 114B above for the average signal intensity obtained under the first polarization condition for every shot SAn of the wafer 10. The average signal intensity obtained under the second polarization condition is subtracted from the brightness corrected in b) to calculate an average signal intensity difference Δn, and the calculation result is stored in the storage unit 85A (step 146B). Thereafter, the third calculation unit calculates the corresponding exposure amount Dn by applying the difference Δn in the average signal intensity to the reference dose curve stored in step 116B for every shot SAn of the wafer 10 and calculating the corresponding exposure amount Dn. The result is stored in the storage unit 85A (step 148B).

  Furthermore, the image processing unit 40A calculates an average signal intensity (average luminance) for every shot of the wafer 10 using the corresponding digital images with respect to the second set of first and second polarization conditions, The calculation result is output to the inspection unit 60A. The third arithmetic unit in the inspection unit 60A then calculates the average signal intensity obtained under the first polarization condition for each shot SAn of the wafer 10 (the gain a ′ and the gain a ′ and the coefficient calculated in step 120B). An average signal difference Δn ′ is calculated by subtracting the average signal intensity obtained under the second polarization condition from the luminance corrected by the offset b ′), and the calculation result is stored in the storage unit 85A (step 150B). Thereafter, the third calculation unit calculates the corresponding focus value Fn by applying the difference Δn ′ in the average signal intensity to the reference focus curve stored in step 122B for every shot SAn of the wafer 10, and The calculation result is stored in the storage unit 85A (step 152B).

  In the next step 154B, as an example, the control unit 80A of the evaluation apparatus 1A outputs the exposure amount Dn and the focus value Fn data (evaluation data) obtained for each shot of the wafer 10 to the host computer 600. In response to this, the host computer 600 compares the evaluation data sent from the evaluation apparatus 1A with the non-defective product range map PW1 (process window) of FIG. 16 registered as the ID data of the exposure apparatus 100A, and the wafer is compared. It is determined whether the exposure amount and the focus value of each of the ten shots enter the non-defective region GSA.

  For example, when there is a shot in which the exposure amount and the focus value do not enter the non-defective area GSA on the wafer 10 or when the ratio of the shot in which the exposure amount and the focus value do not enter the non-defective area GSA exceeds a predetermined ratio ( Step 156B), the host computer 600 determines that the evaluated wafer 10 is out of the non-defective range. When it is determined that the wafer 10 is within the non-defective range, the operation proceeds to step 164B, and the wafer 10 proceeds to the next process (such as etching in the etching apparatus 300).

  On the other hand, when it is determined that the wafer 10 is out of the non-defective range, the host computer 600 proceeds to step 158B as an example, and determines whether the wafer 10 is to be re-inspected by the SEM 400. When re-inspection is performed, the wafer 10 is sent to the SEM 400 to re-inspect whether the line width and the evaluation target pattern are within the allowable range (step 160B). If the wafer 10 is a non-defective product as a result of the re-inspection (step 162B), the process proceeds to step 164B (next process).

  If it is determined in step 158B that re-inspection by the SEM 400 is not performed, and if re-inspection by the SEM 400 in step 160B determines that the wafer 10 is out of the non-defective range, the operation proceeds to step 166B, and an example The wafer 10 is reused (reworked) after resist stripping. In step 166B, instead of reworking or together with reworking, an alarm may be issued from the host computer 600 to the control unit (not shown) of the exposure apparatus 100A that a wafer outside the non-defective range has occurred. In response to this, the exposure apparatus 100A corrects the width distribution in the scanning direction of the illumination area during scanning exposure, for example. This reduces errors in the exposure amount and the focus position during subsequent exposure. Note that the determination in step 154B may be performed by the calculation unit 50A in the evaluation apparatus 1A.

  As described above, the device manufacturing method of the present embodiment forms the repeated pattern 12 on the surface of the wafer 10 through a processing step including a lithography step including exposure in the exposure apparatus 100A and development in the coater / developer 200 (step). 140B), the surface of the wafer 10 is illuminated, the diffracted light emitted from the surface of the wafer 10 is received (step 144B), and the exposure conditions (exposure amount and focus position) of the repetitive pattern 12 are calculated based on the received light. (Steps 148B and 152B), the calculated exposure condition of the repetitive pattern 12 is compared with the non-defective product range map PW1 (process window) as data defining the quality of the exposure condition of the pattern in the exposure process. Whether the exposure conditions are good or not is determined (step 154B). .

  The evaluation method using the evaluation apparatus 1A of the present embodiment illuminates the surface of the wafer 10 on which the repeated pattern 12 to be inspected is formed on the surface through the exposure process by the exposure apparatus 100A and the development process by the coater / developer 200. Then, the light emitted from the surface of the wafer 10 is received (step 144B), the exposure condition of the repeated pattern 12 is calculated based on the received light (steps 148B and 152B), and the calculated exposure condition of the repeated pattern 12 Then, the quality of the exposure condition of the repeated pattern 12 is judged by comparing with a good product range map that defines the quality of the exposure condition in the exposure process for forming the repeated pattern 12 (step 154B).

  According to this embodiment, by using the wafer 10 having the concave and convex repetitive pattern 12 provided by exposure under a plurality of exposure conditions as a plurality of processing conditions, the exposure amount among the plurality of exposure conditions In addition, the focus position can be evaluated with high accuracy while other influences are suppressed. In addition, there is no need to use a separate measurement pattern, and the exposure conditions can be evaluated by detecting light from the wafer on which the actual device pattern is formed. And can be evaluated with high accuracy.

  Conventionally, it has been assumed that a non-defective range map uniquely created by each evaluation apparatus is compared with the exposure conditions calculated by the evaluation apparatus. However, according to the present embodiment, it is possible to compare the non-defective range map (process window, that is, the reference for the non-defective range) created by the device manufacturer with the exposure condition calculated by the evaluation apparatus. As a result, it is possible to solve problems that have been missed conventionally and problems that have not been evaluated as defective if a process window is used.

In the third embodiment, the following modifications are possible.
First, also in the third embodiment, a method for evaluating two exposure conditions (or three or more exposure conditions) by the evaluation apparatus 1A is arbitrary.
Further, in the third embodiment, the exposure amount and the focus position are inspected as the exposure conditions. As the exposure conditions, the exposure light wavelength, the illumination conditions (for example, the coherence factor (σ value)) in the exposure apparatus 100A, The inspection of the above embodiment may be used to inspect the numerical aperture of the projection optical system PL or the temperature of the liquid during immersion exposure.

In the evaluation apparatus 1A, a variable shutter mechanism including a liquid crystal display element can be used instead of the aperture plates 43A and 43B.
Further, the angle formed by the periodic direction of the repeated pattern 12 on the wafer surface and the vibration direction of the linearly polarized illumination light on the wafer surface is set to 22.5 degrees or 67.5 degrees, thereby detecting sensitivity (with respect to changes in exposure conditions). When the detection signal change ratio) increases, the angle may be changed from 45 degrees. The angle is not limited to these and can be set to an arbitrary angle.

When the specularly reflected light from the wafer 10 is elliptically polarized light and the minor axis direction of the elliptically polarized light is not orthogonal to the polarization direction of the incident light, the transmission axis of the light receiving side polarizing filter 32A is set to the short axis of the elliptically polarized light. You may make it match | combine with an axial direction. This may improve the detection sensitivity (the ratio of the change in the detection signal to the change in the exposure condition).
It is also possible to shift the polarization direction of the illumination light ILI incident on the wafer surface by rotating the illumination-side polarizing filter 26A from the P-polarized light. However, even in this case, the polarization direction of the light receiving side polarizing filter 32A is set in a crossed Nicols state with respect to the illumination side polarizing filter 26A.

Further, by controlling the position of the opening 43Aa of the illumination system aperture stop 43A (and the position of the opening 43Ba of the light receiving system aperture stop 43B), it is possible to change the incident angle of the illumination light ILI with respect to the wafer surface. Thus, when changing the incident angle, the incident angle is also included in one polarization condition.
In addition, the operations in steps 104B and 172 are performed so as to repeat the imaging of the wafer surface image and the movement (step movement) of the stage 5A until an image of the entire surface of the wafer surface is obtained, for example, under the first polarization condition. Hereinafter, the imaging of the wafer surface and the movement of the stage 5A may be repeated under the second polarization condition or the like.

  In step 106B, in order to reduce the influence of the aberration of the projection optical system at the time of exposure, the average signal intensity (average luminance) obtained by averaging the signal intensities of the pixels in the central region of all shots of the conditioned wafer. ) And the calculation result may be output to the inspection unit 60A. However, the influence of the aberration of the projection optical system (error distribution given to the digital image) can be obtained in advance, and the influence of the aberration can be corrected at the stage of the digital image.

Further, the non-defective product range map PW1 may be stored in the storage unit 85A of the evaluation apparatus 1A instead of the host computer.
Further, the reference dose curve SD1 may be approximated by a linear expression or a high-order polynomial regarding the exposure amount. Similarly, the reference focus curve SF1 may be approximated by a linear expression or a high-order polynomial regarding the focus value.

In the determination of the conditions of the third embodiment, the dimension map WM1 of FIG. 16A may be created using the evaluation result regarding the resist pattern instead of the pattern after etching.
Further, the inspection of the evaluation area MAE in each shot SAn and the patterns in the evaluation points MA1 to MA3 by the SEM 400 may be sequentially performed for each shot. Further, the number of evaluation points MA1 to MA3 to be inspected is arbitrary, and there may be one evaluation point. Further, the line width may be inspected without inspecting the evaluation point pattern.

  In the third embodiment, in the condition determining step, the size map WM1 indicating the line width of the pattern in the shot SAn and the three maps indicating the range of shots in which the patterns of the evaluation points MA1 to MA3 are good. Thus, a non-defective range map PW1 is created. In addition to this, the line width of the pattern in the evaluation region in each shot SAn of the wafer 10 is measured by the SEM 400, and a dimension map WM1 which is a map in which the average value of the line width of the measurement result is assigned to each shot SAn is created. Then, the non-defective product range map PW1 may be created from the dimension map WM1. In this case, it is desirable that the evaluation area for measuring the line width is a plurality of different areas in each shot SAn in terms of improving the reliability of the non-defective range map PW1. Further, the non-defective range map PW1 may be created based on the result of the pattern shape evaluation of the evaluation points MA1 to MA3 without using the dimension map WM1.

The good product range map PW1 can also be created by a control unit (not shown) of the SEM 400. Further, the information on the non-defective range map PW1 may be transmitted from the host computer 600 to a control unit (not shown) of the exposure apparatus 100 and recorded in a storage device in the control unit.
In the third embodiment, the in-shot average signal intensity of all shots of the wafer 10 is calculated, and it is determined whether each shot is within the non-defective range. However, as another method, in steps 146B and 150B, an average signal intensity is obtained for each of the I setting areas 16 (see FIG. 5C) in all shots SAn of the wafer 10, and in step 154B, the shots SAn. You may evaluate whether it is in a non-defective range for every setting area 16 in it.

In the third embodiment, the polarization inspection is performed using the evaluation apparatus 1A. However, the wafer surface diffraction inspection (the inspection performed by detecting the diffracted light ILD from the wafer 10) is performed using the evaluation apparatus 1A. ) May be performed.
In order to perform diffraction inspection of the wafer surface using the evaluation apparatus 1A, the control unit 80A reads recipe information (inspection conditions, procedures, etc.) stored in the storage unit 85A and performs the following processing. First, the illumination side polarizing filter 26 and the light receiving side polarizing filter 32 in FIG. 21A are taken out from the optical path, and the wafer 10 is transferred onto the stage 5A via the alignment mechanism by a wafer loader system (not shown).

  Next, the direction of the incident surface of the illumination light ILI on the wafer surface (illumination direction) and the periodic direction (or repetition direction) of the repeated pattern 12 in each shot SAn (see FIG. 5A) match. The rotation angle of the stage 5A (wafer 10) (rotation angle around an axis parallel to the Z axis) is adjusted. Further, the pitch of the repetitive pattern 12 is P, the wavelength of the illumination light ILI incident on the wafer 10 is λ, the incident angle of the illumination light ILI is θ1, and the nth order of the detection target emitted from the wafer surface (n is an integer other than 0) When the diffraction angle of the diffracted light ILD is θ2, the position of the opening 43Ba of the light receiving system aperture stop 43B is adjusted so as to satisfy the above formula (1).

  Next, emission of illumination light ILI having a predetermined selected wavelength from the illumination unit 21 is started. Thereby, the illumination light ILI emitted from the light guide fiber 24 is irradiated onto the wafer surface via the illumination lens 42A, the aperture 43Aa of the illumination system aperture stop 43A, the beam splitter 45, and the objective lens 42B. The diffracted light diffracted on the wafer surface is incident on the image sensor 47 via the objective lens 42B of the light receiving system 30A, the beam splitter 45, the opening 43Ba of the light receiving system aperture stop 43B, and the imaging lens 42C. A partial image (diffraction image) of the wafer 10 is formed on the surface. The image sensor 47 outputs an image signal of the image to the image processing unit 40A, and the image processing unit 40A generates a digital image of a part of the wafer surface and outputs information on the image to the inspection unit 60A.

Then, the wavelength λ of the illumination light ILI when the level of each image signal of the digital image obtained from the image on the wafer surface (the luminance of the image of the corresponding portion) is equal to or greater than an intensity (luminance) on average. A combination of the positions (diffraction angles) of the openings 43Ba of the light receiving system aperture stop 43B is referred to as one diffraction condition. A plurality of diffraction conditions are included in the recipe information. By selecting the optimum diffraction condition from the plurality of diffraction conditions, the exposure condition of the wafer 10 can be evaluated in the same manner as in the polarization inspection.
In the third embodiment, when the evaluation apparatus 1A performs only the diffraction inspection, the illumination side polarization filter 26A and the light reception side polarization filter 32A, and these are inserted into and removed from the optical paths of the illumination light and the diffraction light. The mechanism (such as the drive unit 46) can be omitted.
Furthermore, when the evaluation apparatus 1A performs only the polarization inspection, the illumination side polarization filter 26A and the light reception side polarization filter 32A may be left installed in the optical paths of the illumination light and the reflected light, respectively. In this case, a mechanism for inserting and removing the illumination side polarization filter 26A and the light reception side polarization filter 32A in the optical paths of the illumination light and the diffracted light can be omitted.

  As in the first embodiment described above, in this embodiment, the wafer may be illuminated with circularly polarized light or may be illuminated with elliptically polarized light other than circularly polarized light. A light source that emits linearly polarized light or elliptically polarized light can also be used.

  In each of the above-described embodiments, the exposure apparatuses 100 and 100A are scanning steppers using the immersion exposure method. However, the above-described implementation is also performed when an exposure apparatus such as a dry scanning stepper or a stepper is used as the exposure apparatus. The same effect can be obtained by applying the form. Furthermore, the above-described embodiment is also used when the exposure apparatus uses an EUV exposure apparatus that uses EUV light (Extreme Ultraviolet Light) having a wavelength of 100 nm or less as exposure light, or an electron beam exposure apparatus that uses an electron beam as an exposure beam. Is applicable.

  Further, as shown in FIG. 24, a semiconductor device (not shown) includes a design process (step 221) for performing function / performance design of the device, and a mask manufacturing process (for manufacturing a mask (reticle) based on this design process). Step 222), a substrate manufacturing process (Step 223) for manufacturing a wafer substrate from a silicon material or the like, a substrate processing process (Step 224) for forming a pattern on the wafer by the device manufacturing system DMS or a pattern forming method using the same. It is manufactured through an assembly process (step 225) including a dicing process for assembling a device, a bonding process, a packaging process, and the like, and an inspection process (step 226) for inspecting the device. In the substrate processing step (step 224), a resist is applied to the wafer by the device manufacturing system DMS, an exposure step in which the reticle pattern is exposed to the wafer by the exposure apparatuses 100 and 100A in the device manufacturing system DMS, and the wafer is developed. A lithography process including a developing process and an evaluation process for evaluating exposure conditions and the like using light from the wafer are performed by the evaluation apparatuses 1 and 1A.

In such a semiconductor device manufacturing method, the exposure conditions and the like are evaluated using the evaluation apparatus 1 and 1A described above, and the semiconductor finally manufactured by correcting the exposure conditions and the like based on the evaluation results, for example. Yield can be improved.
In the device manufacturing method of the present embodiment, the method of manufacturing a semiconductor device has been particularly described. However, the device manufacturing method of the present embodiment can be applied to a semiconductor material such as a liquid crystal panel or a magnetic disk in addition to a device using a semiconductor material. The present invention can also be applied to the manufacture of devices using other materials.

  Note that the requirements of the above-described embodiments can be combined as appropriate. Some components may not be used. In addition, as long as it is permitted by law, the disclosure of all published publications and US patents related to the inspection devices and inspection methods cited in the above embodiments and modifications are incorporated herein by reference.

  DESCRIPTION OF SYMBOLS 1 ... Evaluation apparatus, 5 ... Stage, 10 ... Wafer, 10a ... Conditional wafer, 20 ... Illumination system, 30 ... Light receiving system, 35 ... Imaging part, 40 ... Image processing part, 50 ... Calculation part, 60 ... Inspection part, 85 ... Storage unit, 100 ... Exposure apparatus, DMS ... Device manufacturing system

Claims (20)

Through the processing process by the processing equipment, form a pattern on the surface of the substrate,
Illuminating the surface of the substrate;
Receiving light emitted from the surface of the substrate;
Based on the received light, calculate the processing conditions of the pattern,
Compare the calculated processing conditions of the pattern with the data defining the quality of the processing conditions of the pattern in the processing step,
A device manufacturing method including determining whether the processing conditions of the pattern are good or bad. The processing apparatus includes an exposure apparatus,
The processing step includes an exposure step by an exposure apparatus,
The device manufacturing method according to claim 1, wherein the processing condition includes an exposure condition that is at least one of an exposure amount and a focus of exposure by an exposure apparatus.   The device manufacturing method according to claim 2, wherein the data defining the quality of the exposure condition includes a process window that defines a range of exposure amount and focus quality of exposure by an exposure apparatus. The processing apparatus includes an etching apparatus,
The processing step includes an etching step by an etching apparatus,
The device manufacturing method according to claim 1, wherein the processing conditions include etching conditions by an etching apparatus.   5. The method according to claim 1, further comprising notifying at least one of a processing device and an arithmetic device capable of communicating with the plurality of processing devices, the result of determining whether the processing conditions of the pattern are good or bad. Device manufacturing method.   The device manufacturing method according to claim 5, wherein the apparatus condition of the processing apparatus is adjusted based on the result of determining the quality of the notified processing condition.   The method includes notifying a processing device and an arithmetic device capable of communicating with a plurality of processing devices of a deviation amount between the calculated processing conditions of the pattern and an optimum condition among data defining the quality of the processing conditions. The device manufacturing method as described in any one of 1-6.   The device manufacturing method according to claim 1, further comprising: determining whether the pattern processing conditions are good and issuing a warning based on the result.   9. The method according to claim 1, further comprising: issuing a warning when the calculated processing condition of the pattern is included in a range of defective products of the processing condition in data defining the quality of the processing condition. Device manufacturing method. Illuminating the surface of the substrate with polarized light;
Receiving polarized light emitted from the surface of the substrate;
The device manufacturing method as described in any one of Claims 1-9 which calculates the process conditions of the said pattern based on the intensity | strength of the received polarized light. Receiving diffracted light emitted from the surface of the substrate;
The device manufacturing method according to any one of claims 1 to 10, wherein a processing condition of the pattern is calculated based on the intensity of received diffracted light. Illuminates the entire surface of the substrate in a lump,
Based on the light emitted from the surface of the substrate, capture an image of the entire surface of the substrate,
The device manufacturing method according to claim 1, wherein a processing condition of the pattern is calculated based on a signal intensity of an image of the entire surface of the substrate acquired by imaging. Illuminating a portion of the surface of the substrate;
Based on the light emitted from the surface of the substrate, capture an image of a portion of the surface of the substrate,
The region for illuminating the substrate and the substrate are relatively moved so that light for illuminating a part of the surface of the substrate is sequentially irradiated on the entire surface of the substrate.
The device manufacturing method according to claim 1, wherein a processing condition for the pattern is calculated based on a signal intensity of an image of the surface of the substrate acquired by imaging. Through the exposure process by the exposure apparatus, the surface of the substrate on which the pattern to be inspected is formed is illuminated,
Receiving light emitted from the surface of the substrate;
Based on the received light, calculate the exposure condition of the pattern,
Compare the calculated exposure condition of the pattern with data defining the quality of the exposure condition of the pattern in the exposure step,
An evaluation method comprising determining whether the exposure condition of the pattern is good or bad.   The evaluation method according to claim 14, wherein the exposure condition is an exposure amount and a focus of exposure by an exposure apparatus.   16. The evaluation method according to claim 14, wherein the data defining the quality of the exposure condition includes a process window that defines a range of exposure amount and focus quality of exposure by an exposure apparatus. An illumination unit that illuminates the surface of the substrate having a pattern formed on the surface through a processing step by the processing apparatus;
A detection unit for detecting light emitted from the surface of the substrate;
The processing conditions of the pattern are calculated based on the light detected by the detection unit, the calculated processing conditions are compared with data defining the quality of the processing conditions of the pattern in the processing step, and the processing conditions of the pattern An arithmetic unit for determining pass / fail;
An evaluation apparatus comprising: The processing apparatus includes an exposure apparatus,
The processing step includes an exposure step by an exposure apparatus,
The evaluation apparatus according to claim 17, wherein the processing condition includes an exposure condition that is at least one of an exposure amount and a focus of exposure by an exposure apparatus.   18. The evaluation apparatus according to claim 17, wherein the data defining the quality of the processing conditions includes a process window that defines a range of exposure amount and focus quality of exposure by an exposure apparatus. The processing apparatus includes an etching apparatus,
The processing step includes an etching step by an etching apparatus,
The evaluation apparatus according to claim 17, wherein the processing condition includes an etching condition by an etching apparatus.

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