WO2014104194A1 - 検査装置、検査方法、露光システム及び露光方法、並びにデバイス製造方法 - Google Patents
検査装置、検査方法、露光システム及び露光方法、並びにデバイス製造方法 Download PDFInfo
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- WO2014104194A1 WO2014104194A1 PCT/JP2013/084890 JP2013084890W WO2014104194A1 WO 2014104194 A1 WO2014104194 A1 WO 2014104194A1 JP 2013084890 W JP2013084890 W JP 2013084890W WO 2014104194 A1 WO2014104194 A1 WO 2014104194A1
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/0002—Inspection of images, e.g. flaw detection
- G06T7/0004—Industrial image inspection
- G06T7/0008—Industrial image inspection checking presence/absence
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N21/956—Inspecting patterns on the surface of objects
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
- G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
- G03F7/70605—Workpiece metrology
- G03F7/70616—Monitoring the printed patterns
- G03F7/70625—Dimensions, e.g. line width, critical dimension [CD], profile, sidewall angle or edge roughness
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- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
- G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
- G03F7/70605—Workpiece metrology
- G03F7/70616—Monitoring the printed patterns
- G03F7/70641—Focus
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T7/00—Image analysis
- G06T7/0002—Inspection of images, e.g. flaw detection
- G06T7/0004—Industrial image inspection
- G06T7/001—Industrial image inspection using an image reference approach
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
- G06V10/00—Arrangements for image or video recognition or understanding
- G06V10/94—Hardware or software architectures specially adapted for image or video understanding
- G06V10/955—Hardware or software architectures specially adapted for image or video understanding using specific electronic processors
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/10—Image acquisition modality
- G06T2207/10004—Still image; Photographic image
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/10—Image acquisition modality
- G06T2207/10141—Special mode during image acquisition
- G06T2207/10152—Varying illumination
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06T—IMAGE DATA PROCESSING OR GENERATION, IN GENERAL
- G06T2207/00—Indexing scheme for image analysis or image enhancement
- G06T2207/30—Subject of image; Context of image processing
- G06T2207/30108—Industrial image inspection
- G06T2207/30148—Semiconductor; IC; Wafer
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L22/00—Testing or measuring during manufacture or treatment; Reliability measurements, i.e. testing of parts without further processing to modify the parts as such; Structural arrangements therefor
- H01L22/10—Measuring as part of the manufacturing process
- H01L22/12—Measuring as part of the manufacturing process for structural parameters, e.g. thickness, line width, refractive index, temperature, warp, bond strength, defects, optical inspection, electrical measurement of structural dimensions, metallurgic measurement of diffusions
Definitions
- the present invention relates to an inspection technique for determining a processing condition of a pattern formed on a substrate, an exposure technique using the inspection technique, and a device manufacturing technique using the exposure technique.
- 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 amount
- a focus position an object to be exposed to an image plane of a projection optical system
- It is necessary to manage a plurality of exposure conditions such as a substrate defocus amount) and an exposure wavelength with high accuracy. For this purpose, it is necessary to determine the actual exposure conditions of the exposure apparatus with high accuracy by using the exposure apparatus to expose the substrate and using a pattern or the like formed on the exposed substrate.
- 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.
- a method of sequentially exposing each shot, measuring a lateral shift amount of a resist pattern obtained by development after exposure, and determining a focus position at the time of exposure of each shot from the measurement result for example, Patent Literature 1.
- the measurement result includes some influences such as variations in exposure amount.
- An aspect of the present invention has been made in view of such problems, and uses a substrate having a pattern provided by processing under a plurality of processing conditions (for example, exposure conditions), and the plurality of processing. It aims at determining each processing condition of conditions with high precision.
- a plurality of processing conditions for example, exposure conditions
- a stage capable of holding the substrate on which the pattern is formed, and an illumination unit that illuminates the surface of the substrate with polarized light
- a detector that receives light emitted from the surface of the substrate and detects a condition that defines a polarization state of the light; and the polarization of the light emitted from the substrate on which a pattern is formed under the known processing conditions.
- a storage unit for storing an apparatus condition for determining the processing condition of the inspection target pattern formed on the surface of the inspection target substrate based on the condition defining the state;
- An inspection unit that determines the processing condition of the inspection target pattern based on a condition that defines the polarization state of light emitted from the surface of the inspection target substrate under the apparatus condition;
- An inspection apparatus is provided.
- the exposure unit having a projection optical system that exposes the pattern on the surface of the substrate, the inspection apparatus of the first aspect, and the processing conditions determined by the inspection apparatus
- An exposure system includes a control unit that corrects processing conditions in the exposure unit.
- the inspection method for determining the processing condition of the pattern to be inspected based on the condition that defines the polarization state of the light emitted from the substrate on which the pattern is formed under the known processing condition.
- the pattern is exposed on the surface of the substrate, the processing condition of the substrate is determined using the inspection method of the third aspect, and the processing condition determined by the inspection method Accordingly, an exposure method for correcting the processing conditions during exposure of the substrate is provided.
- it is a device manufacturing method which has the process process which provides a pattern on the surface of a board
- each processing condition of the plurality of processing conditions can be evaluated with high accuracy.
- (A) is a figure which shows the whole structure of the inspection apparatus which concerns on embodiment, (b) is a top view which shows a wafer, (c) is a top view which shows a conditionally adjusted wafer.
- (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.
- (A) is a figure which shows an example of the relationship between exposure amount and the change of a polarization state
- (b) is a figure which shows an example of the relationship between a focus position and the change of a polarization state.
- (A) is a plan view showing an example of a shot arrangement of the conditioned wafer 10
- (b) is an enlarged view showing one shot
- (c) is an enlarged view showing an example of an arrangement of a plurality of setting areas in the shot. is there.
- (A) is a figure which shows an example of the change of the signal intensity distribution corresponding to the Stokes parameter S2 when the incident angle is changed
- (b) is the change of the luminance distribution corresponding to the Stokes parameter S3 when the incident angle is changed. It is a figure which shows an example.
- FIG. (A) And (b) is a figure which shows an example of the change of the sensitivity with respect to the change of the exposure amount and focus position of Stokes parameters S1-S3 when an incident angle is changed, respectively.
- (A), (b), and (c) show an example of a change in sensitivity with respect to a change in exposure amount and focus position of Stokes parameters S1, S2, and S3, respectively, when the angle of the polarization direction of incident light is changed.
- FIG. (A) and (b) are diagrams showing examples of the relationship between the Stokes parameter S2, the exposure amount and the focus value, respectively.
- (C) and (d) are examples of the relationship between the Stokes parameter S3, the exposure amount and the focus value, respectively.
- FIG. 13 (b) is an enlarged sectional view showing a part of a pattern formed on the wafer, and (e) shows an example of a change in the Stokes parameters S2 and S3 with respect to the deposition amount of the spacer layer.
- 4F is a diagram showing an example of changes in the Stokes parameters S2 and S3 with respect to the etching amount. It is a flowchart which shows an example of the method (condition extraction) which calculates
- (A) is a figure which shows the inspection apparatus of 3rd Embodiment
- (b) is a schematic block diagram which shows exposure apparatus.
- FIG. 1A shows an inspection apparatus 1 according to this embodiment.
- an inspection apparatus 1 includes a stage 5 that supports a substantially disc-shaped semiconductor wafer (hereinafter simply referred to as a wafer) 10, and a wafer 10 conveyed by a conveyance system (not shown) It is mounted on the upper surface (mounting surface) of the stage 5 and fixed and held, for example, by vacuum suction.
- the X axis is taken in a direction parallel to the paper surface of FIG.
- the Y axis is taken in a direction perpendicular to the paper surface of FIG.
- the Z axis is taken in the direction perpendicular to the plane including the X axis and the Y axis.
- FIGS. 1B and 1C to 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.
- the stage 5 has a first drive unit (not shown) that controls a rotation angle ⁇ 1 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.
- a tilt angle ⁇ 2 tilt of the surface of the wafer 10
- TA tilt axis
- It is supported by a base member (not shown) via a second drive unit (not shown) that controls the angle.
- the inspection apparatus 1 further includes an illumination system 20 that irradiates illumination light ILI as parallel light onto the surface of the wafer 10 (hereinafter referred to as a wafer surface) supported by the stage 5 and having a predetermined repetitive pattern formed on the surface.
- a light receiving system 30 that collects light (regular reflection light, diffracted light, etc.) emitted from the wafer surface upon irradiation with the illumination light ILI and an image on the wafer surface that receives light collected by the light receiving system 30
- Imaging device 35 an image processing unit 40 that obtains a condition for defining a polarization state by processing an image signal output from the imaging device 35, and exposure condition (processing) of the pattern on the wafer surface using the information on the condition
- a calculation unit 50 that performs a determination of (condition).
- 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.
- a two-dimensional imaging device 35b such as a CCD or a CMOS
- the image processing unit 40 Based on the image signal of the wafer 10 input from the imaging device 35, the image processing unit 40 performs digital image of the wafer 10 (signal intensity for each pixel, signal intensity averaged for each shot, or for each area smaller than the shot. (Averaged signal intensity and the like) information is generated, and Stokes parameters described later as conditions for defining the polarization state obtained based on this information are output to the arithmetic unit 50.
- the conditions for defining the state of polarization include, for example, a first prescribed condition and a second prescribed condition.
- the first prescribed condition is a Stokes parameter S2 described later
- the second prescribed condition is a Stokes parameter S3 described later.
- the image processing unit 40 is configured to simply output digital image information (information on signal intensity distribution for each pixel, etc.) to the calculation unit 50.
- the calculation unit 50 includes an inspection unit 60 including calculation units 60a, 60b, and 60c that processes information such as Stokes parameters, a control unit 80 that controls operations of the image processing unit 40 and the inspection unit 60, and an image. And a signal output unit 90 that outputs an inspection result (described later) of the obtained exposure conditions to a control unit (not shown) of the exposure apparatus 100.
- the illumination system 20 includes an illumination unit 21 that emits illumination light, and an illumination-side concave mirror 25 that reflects the illumination light emitted from the illumination unit 21 toward the wafer surface as parallel light.
- the illumination unit 21 emits light having a predetermined wavelength (for example, different wavelengths ⁇ 1, ⁇ 2, ⁇ 3, etc.) out of light from the light source unit 22 according to a command from the control unit 80 and a light source unit 22 such as a metal halide lamp or a mercury lamp.
- a dimming unit 23 that selects and adjusts the intensity
- a light guide fiber 24 that emits light selected by the dimming unit 23 and adjusted in intensity from a predetermined emission surface to the illumination-side concave mirror 25, and
- a polarizer 26 that converts the illumination light emitted from the exit surface into linearly polarized light.
- the polarizer 26 is, for example, a polarizing plate having a transmission axis, and passes through the center of the incident surface 26a on which illumination light emitted from the exit surface of the light guide fiber 24 enters, and an axis orthogonal to the incident surface 26a is used as a rotation axis. It can be rotated.
- the direction of the transmission axis of the polarizer 26 can be set to an arbitrary direction, and the polarization direction of the linearly polarized light incident on the wafer surface via the polarizer 26 (that is, the vibration direction of the linearly polarized light) can be arbitrarily set. Can be in the direction.
- the rotation angle of the polarizer 26 (that is, the direction of the transmission axis of the polarizer 26) is controlled by a drive unit (not shown) based on a command from the control unit 80.
- the wavelength ⁇ 1 is 248 nm
- ⁇ 2 is 265 nm
- ⁇ 3 is 313 nm.
- 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 ⁇ 1 of the illumination light with respect to the wafer 10 can be adjusted by controlling the position of the exit portion of the light guide fiber 24 and the position and angle of the illumination-side concave mirror 25 via a drive mechanism (not shown) according to a command from the control unit 80. It is.
- the position and angle of the illumination-side concave mirror 25 are controlled by tilting the illumination-side concave mirror 25 about the tilt axis TA of the stage 5, and the incident angle ⁇ 1 of illumination light incident on the wafer surface is adjusted.
- the tilt angle ⁇ 2 of the stage 5 is controlled so that specularly reflected light (light having an emission angle ⁇ 1 from the wafer surface) ILR from the surface of the wafer 10 enters the light receiving system 30.
- the incident angle ⁇ 1 of the illumination light with respect to the wafer surface is an angle formed between the normal line CA of the stage 5 and the principal ray incident on the wafer surface
- the emission angle ⁇ 2 from the wafer 10 is the normal line CA of the stage 5 and the wafer. The angle formed with the chief ray emitted from the surface.
- inspection using linearly polarized light is performed.
- the inspection using the diffracted light other than the specularly reflected light from the wafer 10 can also be performed with the polarizer 26 removed from the optical path or with the polarizer 26 on the optical path.
- the light receiving system 30 includes a light receiving side concave mirror 31 disposed facing the stage 5, a quarter wavelength plate 33 disposed on the optical path of light reflected by the light receiving side concave mirror 31, and a quarter wavelength plate 33.
- the image pickup surface of the image pickup device 35b of the image pickup device 35 is disposed on the focal plane of the light-receiving-side concave mirror 31. Therefore, the parallel light emitted from the wafer surface is condensed by the light receiving side concave mirror 31 and the imaging lens 35a of the imaging device 35, and an image of the wafer 10 is formed on the imaging surface of the imaging element 35b.
- the analyzer 32 is also a polarizing plate having a transmission axis like the polarizer 26, for example, and passes through the center of the incident surface 32a on which the light reflected by the light-receiving side concave mirror 31 is incident and has an axis orthogonal to the incident surface 32a. It can be rotated as a rotation axis. That is, the direction of the transmission axis of the analyzer 32 can be set to an arbitrary direction, and the vibration direction of the linearly polarized light converted by the analyzer 32 can be set to an arbitrary direction.
- the rotation angle of the analyzer 32 (the direction of the transmission axis of the polarizing plate) is controlled by a drive unit (not shown) based on a command from the control unit 80.
- the transmission axis of the analyzer 32 can be set in a direction (crossed Nicols) orthogonal to the transmission axis of the polarizer 26.
- the quarter-wave plate 33 is rotatable about an axis that passes through the center of the incident surface 33a on which the light reflected by the light-receiving side concave mirror 31 is incident and is orthogonal to the incident surface 33a.
- the rotation angle of the quarter-wave plate 33 can be controlled within a range of 360 ° by a drive unit (not shown) based on a command from the control unit 80.
- a Stokes parameter which is a condition for defining the polarization state of reflected light from the wafer 10 as described later, is set for each pixel, for example. Can be requested.
- the wafer 10 is exposed and exposed by a predetermined pattern to the uppermost resist (for example, photosensitive resin) by the exposure apparatus 100 through a reticle, developed by a coater / developer (not shown), and then inspected. Is conveyed onto the stage 5.
- a repetitive pattern 12 (see FIG. 1B) is formed on the upper surface of the wafer 10 transferred onto the stage 5 through exposure and development processes by an exposure apparatus 100 and a coater / developer (not shown). .
- the wafer 10 is aligned on the basis of a pattern in the shot of the wafer 10, a mark on the wafer surface (for example, a search alignment mark), or an outer edge (notch, orientation flat, etc.) by an alignment mechanism (not shown) during the transfer.
- a plurality of shots (shot areas) 11 are arranged on the wafer surface in two directions (X direction and Y direction) orthogonal to each other, and each shot 11 Inside, a repetitive pattern 12 of irregularities such as a line pattern or a hole pattern is formed as a circuit pattern of a semiconductor device.
- the two axes orthogonal to each other are the X axis and the Y axis, and the axis is perpendicular to the plane including the X axis and the Y axis. Is the Z axis.
- the repeating pattern 12 may be a pattern made of a dielectric material such as a resist pattern, or may be a pattern made of a metal. Although one shot 11 often includes a plurality of chip areas, FIG. 1B shows that one chip area is included in one shot for easy understanding.
- the inspection unit 60 processes an image on the wafer surface as will be described later in response to a command from the control unit 80, and exposes the wafer 10 to an exposure amount (so-called dose amount) and a focus position (projection optics in the exposure device).
- a predetermined exposure condition among a plurality of exposure conditions such as the temperature of the liquid between the projection optical system and the wafer in the case of exposing by the immersion method.
- the determination result of the exposure condition is supplied to a control unit (not shown) in the exposure apparatus 100, and the exposure apparatus 100 can correct the exposure condition (for example, correction of offset, variation, etc.) according to the inspection result. it can.
- the exposure condition is an example of a processing condition for a repetitive pattern formed on the wafer.
- the exposure condition includes a first exposure condition as a first processing condition and a second exposure as a second processing condition. Includes conditions.
- the first exposure condition is an exposure amount
- the second exposure condition is a focus position.
- the repetitive pattern 12 on the wafer surface in FIG. 1B is along the arrangement direction (here, the X direction) in which the plurality of line portions 2A are short directions, as shown in FIG. 2A.
- the resist patterns for example, line patterns
- 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.
- the design value of the line width D A of the line portion 2A in the repetitive pattern 12 is set to 1 ⁇ 2 of the pitch P.
- Appropriate exposure conditions i.e., exposure dose and focus position
- 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.
- the shape of the XZ section of the line portion 2A at that time is a square or a rectangle.
- 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 .
- 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.
- the inspection of the present embodiment is performed by changing the polarization state of reflected light from the wafer surface in accordance with the change in the volume ratio between the line portion 2A and the space portion 2B in the repetitive pattern 12 (so-called repetitive pattern on the wafer surface).
- 12 is used to inspect the state (e.g. quality) of the repeated pattern 12 using the change in the polarization state of reflected light due to structural birefringence in FIG.
- 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.
- control unit 80 reads recipe information (inspection conditions, procedures, etc.) stored in the storage unit 85 and performs the following processing.
- recipe information inspection conditions, procedures, etc.
- Stokes parameters S0, S1, S2, and S3 defined by the following equations (Equations 1 to 4) of light regularly reflected on the wafer surface are measured as conditions for defining the polarization state. .
- the axes perpendicular to each other in the plane perpendicular to the optical axis of the light are the x-axis and y-axis, and the intensity of the linearly polarized light component (transversely polarized light) in the x direction is Ix, and the linearly polarized light component (vertically polarized light) in the y direction.
- the intensity of (polarized light) is Imx
- the intensity of the clockwise circular polarization component is Ir
- the intensity of the counterclockwise circular polarization component is Il.
- the Stokes parameter S0 is standardized to be 1.
- the values of the other parameters S1 to S3 are in the range of ⁇ 1 to +1.
- the Stokes parameters (S0, S1, S2, S3) are, for example, (1, 0, -1, 0) for perfect 135 ° polarization and (1, 0, 0, 1) for perfect clockwise circular polarization. Become.
- the wafer 10 on which the repetitive pattern 12 to be inspected is formed is placed at a predetermined position on the stage 5 in a predetermined direction.
- the tilt angle of the stage 5 is such that the regular reflection light ILR from the wafer 10 can be received by the light receiving system 30, that is, the light received by the light receiving system 30 with respect to the incident angle ⁇ 1 of the incident illumination light ILI is reflected on the wafer surface.
- the angles (light reception angle or emission angle) are set to be equal.
- the angle of the polarizer 26 is set so that the illumination light ILI incident on the wafer surface becomes P-polarized light linearly polarized in a direction parallel to the incident surface.
- the rotation angle of the stage 5 is such that the periodic direction of the repetitive pattern 12 on the wafer surface is the illumination light on the wafer surface as shown in FIG. 2B (in FIG. It is set to be inclined at 45 ° with respect to the vibration direction of light L). This is to maximize the signal intensity of the reflected light from the repeated pattern 12.
- the detection sensitivity that is, the change of the detection signal or the parameter with respect to the change of the exposure condition
- the angle may be changed.
- the angle is not limited to these and can be set to an arbitrary angle.
- the periodic direction of the repeated pattern 12 is the incident surface of the light L (that is, the traveling direction of the light L on the wafer surface) as shown in FIG. ) Is set to 45 °
- the angle formed by the vibration direction of the light L on the wafer surface and the periodic direction of the repetitive pattern 12 is also set to 45 °.
- 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 by 45 ° with respect to the periodic direction of the repetitive pattern 12.
- the regular reflected light ILR of the parallel light reflected by the wafer surface is collected by the light receiving side concave mirror 31 of the light receiving system 30 and reaches the image pickup surface of the image pickup device 35 via the quarter wavelength plate 33 and the analyzer 32.
- the polarization state of the specularly reflected light ILR changes to, for example, elliptically polarized light with respect to the linearly polarized light of the incident light.
- the direction of the transmission axis of the analyzer 32 is set so as to be orthogonal to the transmission axis of the polarizer 26 (in a crossed Nicols state).
- the analyzer 32 extracts a polarization component whose vibration direction is substantially perpendicular to the light L and guides it to the imaging device 35.
- an image of the wafer surface is formed on the imaging surface of the imaging device 35 by the polarization component extracted by the analyzer 32. It is also possible to take an image of the wafer surface by shifting the angle of the analyzer 32 by a predetermined angle from the crossed Nicols state.
- the Stokes parameters S0 to S3 indicating the polarization state of the reflected light from the wafer surface are obtained by the rotational phase shifter method.
- the image is picked up by the image pickup device 35b, and the obtained image signal is supplied to the image processing unit 40.
- Information about the rotation angle of the quarter-wave plate 33 is also supplied to the image processing unit 40.
- the image processing unit 40 can obtain the Stokes parameters S0 to S3.
- the rotational phase shifter method is described in, for example, Non-Patent Document 1 as “Method Using Rotating ⁇ / 4 Plate”. Moreover, since the detailed calculation method of Stokes parameter is described also in patent document 2 by this applicant, the calculation method is abbreviate
- the image processing unit 40 outputs the obtained Stokes parameter information for each pixel of the imaging device 35 to the inspection unit 60.
- the inspection unit 60 uses the information to determine an exposure condition or the like in the exposure apparatus 100 used when the repetitive pattern 12 of the wafer 10 is formed.
- the incident angle ⁇ 1 of the illumination light ILI to the wafer surface in the inspection apparatus 1 (or the emission angle ⁇ 2 of the light emitted from the wafer surface), the illumination light ILI wavelength ⁇ ( ⁇ 1 to ⁇ 3, etc.), rotation angle of analyzer 32 (ie, direction of transmission axis of analyzer 32), rotation angle of polarizer 26 (ie, direction of transmission axis of polarizer 26), stage A combination of 5 rotation angles (that is, the orientation of the wafer 10) is called one apparatus condition.
- the apparatus conditions can also be called inspection conditions.
- the apparatus condition can also be called the polarization condition.
- a plurality of apparatus conditions are included in the recipe information of the inspection apparatus 1 stored in the storage unit 85.
- an apparatus condition suitable for determining the exposure condition of the pattern formed on the wafer is selected from the plurality of apparatus conditions.
- the wavelength ⁇ of the illumination light ILI, the incident angle ⁇ 1 of the illumination light ILI with respect to the wafer surface, and the rotation angle of the polarizer 26 are examples of illumination conditions included in the apparatus conditions of the inspection apparatus 1, and light emitted from the wafer surface
- the tilt angle ⁇ 2 (that is, the tilt angle of the wafer surface) is an example of the stage attitude condition included in the apparatus conditions of the inspection apparatus 1.
- the exposure condition of the inspection object of the exposure apparatus 100 be the exposure amount and the focus position.
- the exposure amount during exposure of the pattern formed on the wafer surface is lower than the appropriate amount from the exposure amount D1 (under dose) to the optimum exposure amount D5 (best).
- the pattern pitch and line width change due to the exposure dose D8 (overdose) higher than the appropriate amount after the dose Dbe qualitatively, as shown in FIG.
- the polarization state of the reflected light from both the direction of the major axis of the elliptically polarized light (that is, the inclination of the major axis of the elliptically polarized light) and the ellipticity (that is, the ratio between the length of the minor axis of the elliptically polarized light and the length of the major axis) Changes. Further, since the major axis direction of elliptically polarized light corresponds to the Stokes parameter S2 and the ellipticity corresponds to the Stokes parameters S1 and S3, the Stokes parameters S1, S2, and S3 of the reflected light change when the exposure amount changes.
- the focus position at the time of exposure of the pattern passes through the optimum focus position F4 (best focus Zbe) from the focus position F1 (under focus) lower than the range of the appropriate position,
- the cross-sectional shape of the pattern is between a rectangle (or square) and a trapezoid.
- the polarization state of the reflected light from the wafer surface has a tendency that the major axis direction of the elliptically polarized light is substantially the same and only the ellipticity changes. There is. For this reason, when the focus position changes, the Stokes parameters S1 and S3 of the reflected light tend to change relatively large and the Stokes parameter S2 does not change much. By utilizing the fact that the Stokes parameters that change depending on the exposure conditions differ in this way, it becomes possible to evaluate individual exposure conditions from the measured values of the Stokes parameters.
- the inspection apparatus 1 is used to detect light from a repetitive pattern on the wafer surface, and exposure conditions (here, exposure amount and focus position) of the exposure apparatus 100 used to form the pattern. ) Will be described with reference to the flowchart of FIG. Further, since it is necessary to obtain an apparatus condition (inspection condition) in advance for the determination, an example of a method for obtaining the apparatus condition (hereinafter referred to as “conditioning”) will be described with reference to the flowchart of FIG. These operations are controlled by the control unit 80.
- a wafer 10a shown in FIG. 1C is prepared in step 102 of FIG.
- a scribe line region SL region serving as a boundary when the chips are separated in the device dicing process
- the resist-coated wafer 10a is transported to the exposure apparatus 100 in FIG. 1A, and the exposure apparatus 100 scans the wafer 10a in the scanning direction during, for example, scanning exposure (the longitudinal direction of the shot in FIG. 1C).
- the exposure amount gradually changes between shots arranged in the direction along the Y axis, and is in the non-scanning direction orthogonal to the scanning direction (the short side direction of the shot in FIG. 1C).
- the pattern of the reticle (not shown) for the device that is actually the same product is exposed to each shot SAn while changing the exposure conditions so that the focus position gradually changes between shots arranged in the direction along the axis). To do. Thereafter, by developing the exposed wafer 10a, a wafer 10a (hereinafter referred to as a conditional wafer) 10a in which the pattern 12 is repeatedly formed on each shot SAn under different exposure conditions is created.
- a defocus amount (referred to as a focus value here) with respect to the optimum focus position Zbe is used as the focus position.
- the focus value is set in seven steps from ⁇ 60 nm to 0 nm to +60 nm in increments of 20 nm. Numbers 1 to 7 on the horizontal axis in FIG. 10B, which will be described later, correspond to the seven stages of focus values ( ⁇ 60 to +60 nm).
- a range of an appropriate focus value including an optimum focus position Zbe (focus value is 0) (for example, a focus value at which a device after manufacture does not cause a malfunction) is represented as an appropriate range 50F.
- the focus value can be set in a plurality of stages in increments of 30 nm or 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.
- the exposure dose is 9 steps (10.0 mJ, 11.5 mJ, 13.0 mJ, 14.5 mJ, 16.0 mJ, 17.5 mJ, 19) in 1.5 mJ increments centering on the optimum exposure dose Dbe. .0mJ, 20.5mJ, 22.0mJ).
- the exposure amount is set to 7 levels, and the numbers 1 to 7 of the exposure amount on the horizontal axis in FIG. Yes.
- a range of an appropriate exposure amount including an optimal exposure amount Dbe (for example, an exposure amount at which a manufactured device does not cause a malfunction) is represented as an appropriate range 50D.
- the condition-sharing wafer 10a of the present embodiment is a so-called FEM wafer (Focus Exposure Matrix wafer) that is exposed and developed by shaking the exposure amount and the focus position in a matrix. If the number of shots with different combinations of exposure conditions obtained by the product of the number of focus value steps and the number of exposure dose steps is greater than the number of shots on the entire surface of the conditionally adjusted wafer 10a, the conditionally adjusted wafer 10a is selected. Multiple sheets may be created.
- FEM wafer Focus Exposure Matrix wafer
- a plurality of shots having the same value and exposure amount may be formed, and the measurement values obtained for the shots having the same focus value and exposure amount may be averaged.
- the influence of uneven 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. 2B) during scanning exposure are reduced. Therefore, a plurality of shots having different focus values and exposure amounts may be arranged at random.
- the control unit 80 reads out a plurality of device conditions from the recipe information in the storage unit 85.
- the wavelength ⁇ of the illumination light ILI is any one of the above ⁇ 1, ⁇ 2, and ⁇ 3
- the incident angle ⁇ 1 of the illumination light ILI is any one of 15 °, 30 °, 45 °, and 60 °.
- a condition is assumed in which the rotation angle of the polarizer 26 is set to a plurality of angles at intervals of, for example, about 5 ° with the crossed Nicols state as the center.
- the incident angle ⁇ 1 is actually about 5 ° so as to be any of 15 °, 20 °, 25 °, 30 °, 35 °, 40 °, 45 °, 50 °, 55 °, 60 °, for example.
- An interval may be set.
- the wavelength of the illumination light ILI is set to ⁇ 1 (step 104), the incident angle ⁇ 1 is set to ⁇ 1 (in addition, the tilt angle of the stage 5 is set, and the light receiving angle of the light receiving system 30 is set. (Step 106), the rotation angle of the polarizer 26 is set to ⁇ 1 (Step 108), and the rotation angle of the quarter-wave plate 33 is set to an initial value (Step 110). Then, under this apparatus condition, the illumination light ILI is irradiated on the surface of the conditioned wafer 10a, and the imaging device 35 captures an image of the conditioned wafer 10a and outputs an image signal to the image processing unit 40 (step). 112).
- step 114 it is determined whether or not the quarter wavelength plate 33 is set to all angles. If not set to all angles, the quarter wavelength plate 33 is set to, for example, about 1.41.
- the angle is rotated by 60 ° (that is, an angle obtained by dividing the rotatable angle range 360 ° of the quarter-wave plate 33 by 256) (step 116), and the process returns to step 112 to capture an image of the conditioned wafer 10a.
- step 112 By repeating step 112 until the angle of the quarter-wave plate 33 is rotated by 360 ° in step 114, images of 256 wafers are picked up corresponding to different rotation angles of the quarter-wave plate 33.
- step 118 the image processing unit 40 performs pixel-by-pixel detection on the image sensor 35b from the obtained digital images of 256 (or at least four) wafers by the above-described rotational phase shift method.
- Stokes parameters S0 to S3 are obtained (step 118).
- the Stokes parameters S0 to S3 are output to the first calculation unit 60a of the inspection unit 60.
- the first calculation unit 60a obtains an average value of each Stokes parameter for each shot (hereinafter referred to as a shot average value) as an example. 2 is output to the calculation unit 60b and the storage unit 85.
- FIG. a images AS21, AS22, AS23, and AS24.
- the incident angle is 45 ° (image A23)
- the change in the signal intensity of the Stokes parameter S2 is large.
- FIG. ) Images AS31, AS32, AS33, and AS34.
- the change in Stokes parameter S3 signal intensity is relatively large when the incident angle is 15 ° (image AS31).
- the sensitivity (hereinafter referred to as dose sensitivity) and the focus position, which are absolute values of the ratio of the change in the measured value of the Stokes parameter to the change in the exposure amount Sensitivity (hereinafter referred to as focus sensitivity), which is the absolute value of the ratio of the change in the measured value of the Stokes parameter to the change in the value, was obtained.
- the apparatus conditions for maximizing the dose sensitivity differed for each of the parameters S1 to S3
- the apparatus conditions for maximizing the focus sensitivity varied for each of the parameters S1 to S3.
- FIG. 8A shows the dose sensitivities of the Stokes parameters S1, S2, and S3 obtained from the measurement results obtained by changing the incident angle ⁇ 1 from 15 ° to 60 ° at intervals of 5 °.
- (A) shows the focus sensitivity of the Stokes parameters S1, S2, and S3 obtained from the measurement results obtained by changing the incident angle ⁇ 1 in the same manner.
- FIGS. 8A shows the dose sensitivities of the Stokes parameters S1, S2, and S3 obtained from the measurement results obtained by changing the incident angle ⁇ 1 from 15 ° to 60 ° at intervals of 5 °.
- the incident angles ⁇ 1 (incident angles) at which the dose sensitivities of the parameters S1, S2, and S3 are maximum are 35 °, 45 °, and 40 °, respectively, and the parameters S1, S2 , S3, the incident angles ⁇ 1 that maximize the focus sensitivity are 15 °, 25 °, and 15 °, respectively.
- FIG. 9A shows the focus sensitivity.
- dose sensitivity and focus sensitivity of Stokes parameters S2 and S3 obtained under the same conditions are shown in FIGS. 9B and 9C, respectively.
- the polarization angles when the dose sensitivity and the focus sensitivity of the parameter S1 are maximized are 10 ° and 0 °, respectively.
- the angles when the dose sensitivity and the focus sensitivity of the parameter S2 are maximum are 60 ° and 90 °, respectively.
- the angles at which the focus sensitivity is maximized are 0 ° and 80 °, respectively.
- the apparatus conditions at which the dose sensitivity is maximized are different among the parameters S1 to S3, and the apparatus conditions at which the focus sensitivity is maximized are also different from each other.
- the Stokes parameters S1, S2, and S3 of the reflected light change when the exposure amount changes, and when the focus position changes, the Stokes parameters S1 and S3 of the reflected light relatively change.
- the Stokes parameter S2 does not change so much.
- the exposure amount is determined using the Stokes parameter S2 and / or S3, and the focus position is determined using the Stokes parameter S3.
- the second computing unit 60b has a high dose sensitivity for the Stokes parameters S2 and S3 and a low focus sensitivity for the Stokes parameters S2 and S3.
- a condition (hereinafter referred to as a first apparatus condition) is determined (step 132). Then, the first apparatus condition and the values of the Stokes parameters S2 and S3 corresponding to each exposure amount obtained under the apparatus condition are stored in the storage unit 85 as a table (hereinafter referred to as a template).
- the second computing unit 60b determines a device condition (hereinafter referred to as a second device condition) in which the focus sensitivity of the Stokes parameter S3 is high and the dose sensitivity of the Stokes parameter S3 is low. Then, the second device condition and the value of the Stokes parameter S3 corresponding to each focus value obtained under this device condition are stored in the storage unit 85 as a table (hereinafter referred to as a template) (step 134).
- a second device condition a device condition in which the focus sensitivity of the Stokes parameter S3 is high and the dose sensitivity of the Stokes parameter S3 is low.
- the shot average values of the Stokes parameter S2 with respect to changes in the exposure amount measured under certain apparatus conditions A, B, and C are curves BS21, BS22, and BS23 in FIG.
- the shot average values of the Stokes parameter S2 with respect to changes in the focus value measured under the apparatus conditions A, B, and C are the curves CS21, CS22, and CS23 of FIG. 10B, respectively.
- the shot average values of the Stokes parameter S3 with respect to the change in exposure amount measured under certain apparatus conditions A, B, and C are the curves BS31, BS32, and BS33 in FIG. 10C, respectively.
- the shot average values of the Stokes parameter S3 with respect to the change in the focus value measured under A, B, and C are the curves CS31, CS32, and CS33 in FIG.
- the Stokes parameters S2 and S3 are standardized values, and the curve BS21 and the like are data shown for convenience of explanation.
- the first device condition in which the dose sensitivity of the Stokes parameter S2 is high and the focus sensitivity is low is the device condition A corresponding to the curve BS21 in FIG. 10A and the curve CS21 in FIG.
- the first device condition in which the dose sensitivity of the Stokes parameter S3 is high and the focus sensitivity is low is a device condition B corresponding to the curve BS32 in FIG. 10C and the curve CS32 in FIG.
- the second device condition in which the focus sensitivity of the Stokes parameter S3 is high and the dose sensitivity is low is the device condition A corresponding to the curve CS31 in FIG. 10 (d) and the curve BS31 in FIG. 10 (c).
- the device conditions include the first device condition (device conditions A and B) and the second device condition (device condition B) different from the first device condition.
- the first apparatus condition can be regarded as a first inspection condition
- the second apparatus condition can be regarded as a second inspection condition.
- the condition determination for obtaining the first and second apparatus conditions used when determining the wafer exposure conditions is completed.
- the reflection from the wafer surface using the two apparatus conditions obtained by the above-described condition determination by the inspection apparatus 1 By measuring the Stokes parameter of light, the exposure amount and the focus position in the exposure conditions of the exposure apparatus 100 are determined as follows.
- the inspection operation shown in the flowchart of FIG. 5 can also be called a dose and focus monitor.
- the exposure apparatus 100 is transported to the exposure apparatus 100, and each shot SAn of the wafer 10 is transferred by the exposure apparatus 100.
- the exposure conditions at this time are an appropriate exposure amount determined in accordance with the reticle for the exposure amount in all shots, and an appropriate focus position for the focus position.
- the shot of the wafer 10 is caused by the influence of slight illuminance unevenness in the slit-like illumination area, for example, in the non-scanning direction and stage vibration (including vibration due to disturbance) in the exposure apparatus 100, for example.
- Variations in exposure amount and focus position, etc. occur for each SAn (repetitive pattern for each shot SAn), and variations in exposure amount, focus position, etc. occur for each of the plurality of setting areas 16 in each shot SAn.
- an unintended exposure change for example, a change from an appropriate exposure amount
- an unintended focus position change for example, a change from an appropriate focus value
- step 150 of FIG. 5 the exposed and developed wafer 10 is loaded onto the stage 5 of the inspection apparatus 1 of FIG. 1A via an alignment mechanism (not shown). And the control part 80 reads the 1st and 2nd apparatus conditions determined by said condition determination from the recipe information of the memory
- the apparatus condition is set to the first apparatus condition (in this case, the apparatus condition A for the Stokes parameter S2) of which the dose sensitivity of the Stokes parameters S2 and S3 is high (step 152), and the quarter wavelength plate 33 is rotated.
- the corner is set to an initial value (step 110A).
- step 112A it is determined whether or not the quarter-wave plate 33 is set to all angles (step 114A). If the quarter-wave plate 33 is not set to all angles, the quarter-wave plate 33 is set to about 1.41 °, for example.
- the angle is rotated by (an angle obtained by dividing the rotation angle range 360 ° by 256) (step 116A), and the process proceeds to step 112A to capture an image of the wafer 10.
- steps 112A By repeating step 112A until the angle of the quarter-wave plate 33 is rotated by 360 ° in step 114A, images of 256 wafer surfaces corresponding to different rotation angles of the quarter-wave plate 33 are taken. .
- step 118A the image processing unit 40 obtains Stokes parameters S2 and S3 for each pixel of the imaging device 35 from the obtained digital images of 256 wafers by the above-described rotational phase shift method.
- the Stokes parameter is output to the first calculation unit 60a of the inspection unit 60.
- the first calculation unit 60a obtains, as an example, the shot average value of the Stokes parameter and outputs the shot average value to the third calculation unit 60c and the storage unit 85.
- the device condition B since the first device condition for the Stokes parameter S3 is the device condition B, the device condition B is set here. Thereafter, Steps 110A to 118A are repeated, and the Stokes parameter (S3 in this case) is obtained and stored for each pixel under the apparatus condition B.
- the second apparatus condition in which the focus sensitivity of the Stokes parameter S3 is high is the same as the apparatus condition A here, the Stokes parameter S3 obtained when the apparatus condition A is set is the second apparatus condition. Used as the obtained Stokes parameter.
- steps 110A to 118A are executed with another device condition set as the second device condition. Then, when the determination under the first and second device conditions is completed in step 154, the operation shifts to step 158.
- the third calculation unit 60c of the inspection unit 60 stores the Stokes parameters S2 and S3 (S2x and S3x) for each pixel obtained under the first apparatus condition in step 132 described above.
- Exposure amounts Dx1 and Dx2 are obtained in light of the templates TD1 and TD2. Actually, the exposure amounts Dx1 and Dx2 are almost the same value.
- the average value of the exposure doses Dx1 and Dx2 may be used as the exposure dose measurement value Dx.
- the distribution of the difference (error) from the optimum exposure amount Dbe of the measured value Dx is supplied to the control unit 80 and further displayed on a display device (not shown).
- the third calculation unit 60c compares the value of the Stokes parameter S3 for each pixel obtained under the second apparatus condition (referred to as S3y) with the template TF1 stored in step 134, and the focus value Fy. Ask for.
- the distribution of the difference (error) of the measured value Fy from the optimum focus position Zbe is supplied to the control unit 80 and further displayed on a display device (not shown).
- the signal output unit 90 controls the exposure unit 100 control unit (not shown) to expose the exposure amount error distribution (unevenness of exposure amount) and focus position error distribution over the entire surface of the wafer 10 ( Information on the distribution of the defocus amount is provided (step 162).
- a control unit (not shown) of the exposure apparatus 100 for example, when the dose unevenness and / or defocus amount distribution exceeds a predetermined allowable range, exposure of the exposure amount and / or focus position is performed.
- correction of the distribution of the width in the scanning direction of the illumination area during scanning exposure is performed.
- the error of the exposure amount distribution and the defocus amount are reduced during the subsequent exposure.
- the exposure apparatus 100 exposes the wafer under the corrected exposure conditions.
- the wafer 10 on which a pattern for a device that is actually a product is formed is used when forming the pattern by performing the determination using the Stokes parameters under two apparatus conditions. It is possible to estimate or determine the exposure amount and the focus position in the exposure condition of the exposure apparatus 100 with high accuracy by removing the influence of each other.
- the inspection apparatus 1 and the inspection method according to the present embodiment set the exposure conditions of the concave / convex repeated pattern 12 provided on the wafer 10 by exposure under a plurality of exposure conditions including the exposure amount and the focus position. An apparatus and method for determination.
- the inspection apparatus 1 includes a stage 5 that can hold the wafer 10 on which the pattern 12 is formed, an illumination system 20 that illuminates the surface of the wafer 10 with linearly polarized illumination light ILI (polarized light), and the wafer 10. Formed on the surface of the wafer 10 to be inspected, and an imaging device 35 and an image processing unit 40 that receive light emitted from the surface of the light and detect Stokes parameters S1 to S3 (conditions for defining the polarization state) of the light.
- ILI linearly polarized illumination light
- a calculation unit that determines the apparatus conditions of the inspection apparatus 1 for determining the exposure conditions of the pattern 12 to be inspected based on the Stokes parameters of the light emitted from the conditionally adjusted wafer 10a on which the pattern 12 is formed under the known exposure conditions 50, and a pattern 1 based on Stokes parameters of light emitted from the surface of the wafer 10 under the apparatus conditions obtained by the calculation unit 50 And to determine the exposure conditions.
- the inspection method of the present embodiment includes steps 112 and 112A for illuminating the surface of the wafer 10 on which the pattern 12 is formed with polarized light and receiving light emitted from the surface of the wafer 10, and Stokes of this light.
- Steps 118 and 118A for detecting parameters and apparatus conditions (inspection conditions) for determining the exposure conditions of the pattern 12 to be inspected formed on the surface of the wafer 10 to be inspected are as follows. Steps 132 and 134 obtained based on the Stokes parameters of the light emitted from the formed conditional wafer 10a, and the exposure of the pattern 12 based on the Stokes parameters of the light emitted from the surface of the wafer 10 under the obtained apparatus conditions. And 158 and 160 for determining the conditions.
- the exposure amount among the plurality of exposure conditions And the focus position can be estimated or determined with high accuracy while the influence of other exposure conditions is suppressed.
- the first and second apparatus conditions used during the inspection of the exposure conditions are patterns that are formed by combining the known first and second exposure conditions (exposure amount and focus position).
- the Stokes parameters S2 and S3 of the light emitted from the conditioned wafer 10a are changed so that the change of the first and second exposure conditions (sensitivity) is larger than that of the other exposure condition. is there. Therefore, the first and second exposure conditions can be determined while suppressing the influence of other exposure conditions.
- the exposure system of the present embodiment includes an exposure apparatus 100 (exposure unit) having a projection optical system that exposes a pattern on the surface of a wafer, and the inspection apparatus 1 of the present embodiment.
- the exposure conditions in the exposure apparatus 100 are corrected according to the first and second exposure conditions determined by 50.
- the first and second exposure conditions of the wafer are determined using the inspection method of the present embodiment (steps 150 to 160), and the first and second estimations estimated by the inspection method are performed.
- the exposure conditions at the time of wafer exposure are corrected in accordance with the exposure conditions 2 (step 162).
- the exposure conditions by the exposure apparatus 100 are corrected according to the first and second exposure conditions estimated by the inspection apparatus 1 or the inspection method using the inspection apparatus 1 and are actually used for device manufacture.
- the exposure condition in the exposure apparatus 100 can be set to a target state efficiently and with high accuracy.
- the first and second apparatus conditions are obtained corresponding to the exposure amount and the focus position. For example, an apparatus condition with high sensitivity is obtained independently for the under dose and the over dose, and the under focus is obtained. In addition, it is also possible to obtain device conditions with high sensitivity independently with respect to overfocus.
- the linearly polarized light obtained by converting the light from the light source unit 22 into linearly polarized light by the polarizer 26 is illuminated on the wafer, but the light that illuminates the wafer may not be linearly polarized light (see FIG. 1 (a)).
- the wafer may be illuminated with circularly polarized light.
- the light from the light source unit 22 is converted into circularly-polarized light by the polarizer 26 and the half-wave plate to illuminate the wafer.
- 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).
- 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.
- the polarizer 26 can be omitted.
- the quarter wavelength plate 33 is disposed on the optical path of the light reflected by the light receiving side concave mirror 31 of the light receiving system 30, but is not limited to this arrangement.
- the quarter wavelength plate 33 may be disposed in the illumination system 20.
- the light from the light guide fiber 24 may be disposed on the optical path of the light that has passed through the polarizer 26. In this case, it is arranged on the optical path between the polarizer 26 and the illumination-side concave mirror 25.
- the exposure conditions of the exposure apparatus 100 are evaluated based on the Stokes parameters calculated from the regular reflection light from the surface of the wafer 10 received by the light receiving system 30.
- the exposure condition may not be regular reflection light.
- diffracted light from the surface of the wafer 10 may be received by the light receiving system 30 and the exposure conditions may be evaluated based on the calculated Stokes parameters.
- the control unit 80 controls the light receiving system 30 so that the light receiving system 30 receives the diffracted light from the surface of the wafer 10 based on known diffraction conditions.
- the plurality of apparatus conditions in this embodiment are conditions including the wavelength ⁇ of the illumination light ILI, the incident angle ⁇ 1 of the illumination light ILI (the exit angle ⁇ 2 of the reflected light), and the rotation angle of the polarizer 26. At least one of ⁇ , the incident angle ⁇ 1, and the rotation angle of the polarizer 26 may be used. Moreover, it is not limited to these conditions.
- the apparatus condition may be any other condition that can be adjusted in the inspection apparatus 1.
- the rotation angle of the analyzer 32 (the azimuth of the transmission axis), the rotation angle of the stage 5 (the azimuth of the wafer 10), and the like may be set as the apparatus conditions.
- the signal output unit 90 may not output the obtained exposure condition determination result to the exposure apparatus 100.
- the signal output unit 90 may output the determination result of the exposure condition to a host computer (not shown) that comprehensively controls the operations of a plurality of exposure apparatuses and the like.
- a host computer not shown
- information on the exposure amount error distribution (uneven amount unevenness) and the focus position error distribution (defocus amount distribution) on the entire surface of the wafer 10 is sent from the signal output unit 90 to the host computer ( (Not shown).
- the host computer (not shown) issues a command for correcting the exposure condition (at least one of the exposure amount and the focus position) to the exposure apparatus 100 or a plurality of exposure apparatuses including the exposure apparatus 100. May be issued.
- the signal output unit 90 may provide a warning to the exposure apparatus 100 or the host computer that the exposure condition is not appropriate based on the obtained determination result of the exposure condition.
- the quarter wavelength plate 33 is rotated by about 1.41 ° (angle obtained by dividing the rotatable angle range 360 ° of the quarter wavelength plate 33 by 256) by the rotational phase shifter method.
- the Stokes parameters are obtained by capturing images of 256 wafers 10, but the angle of the quarter wavelength plate 33 is set to 256 different angles and images of 256 wafers 10 are not captured. Also good. Since there are four unknowns regarding the Stokes parameters (S0 to S3), the angle of the quarter wavelength plate 33 may be set to four different angles, and at least four images of the wafer 10d may be taken.
- the Stokes parameters S0 to S3 are output to the first calculation unit 60a of the inspection unit 60, and the first calculation unit 60a calculates the average value (shot average value) of the Stokes parameters S0 to S3 for each shot. ) Is required, but it may not be the average value for each shot.
- the average value of the Stokes parameters may be obtained for each setting area 16 in the shot. The reason why the shot average value 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.
- a value obtained by averaging the Stokes parameters of the corresponding pixels in the partial area CAn at the center of the shot SAn in FIG. 6B may be calculated. Further, an average value for each pixel corresponding to a plurality of shots may be calculated.
- the average value is calculated for each setting region 16 (see FIG. 6C) such as a rectangle of I (I is an integer of several tens) within the shot SAn.
- the subsequent processing may be performed using the average value of 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.
- the apparatus condition (apparatus condition A) where the dose sensitivity of the Stokes parameter S2 is high and the focus sensitivity is low
- the apparatus condition (apparatus condition) where the dose sensitivity of the Stokes parameter S3 is high and the focus sensitivity is low
- (B) is determined (the first apparatus condition is determined)
- the Stokes parameters S2 and S3 may be calculated by a desired calculation expression so that the difference between the dose sensitivity and the focus sensitivity of the target Stokes parameter becomes larger (the second apparatus condition is also calculated by the same expression). May be calculated).
- arithmetic expressions can be used as the arithmetic expressions of the Stokes parameters S2 and S3.
- the arithmetic expressions such as “S2 + S3” (sum) and “S2 2 + S3 2 ” (square sum) may be used.
- the templates TD1, TD2, and TF1 obtained using the conditionally adjusted wafer 10a on which the repeated pattern is formed by the exposure apparatus 100 are used, and the exposure apparatus 100 used for the condition setting is used.
- the exposure conditions have been obtained, the exposure conditions (exposure amount and focus position) of a machine different from the exposure apparatus 100 may be obtained using the templates TD1, TD2, and TF1.
- the Stokes parameters S0 to S3 are calculated in the condition determination of the present embodiment. However, since the Stokes parameter S0 represents the total intensity of the luminous flux, only the Stokes parameters S1 to S3 are determined in order to determine the exposure conditions. You may ask for it. Further, the Stokes parameter is obtained for each pixel of the image sensor 35b, but may be obtained for each of a plurality of pixels. For example, the Stokes parameter may be obtained every 2 ⁇ 2 pixels. In this embodiment, the Stokes parameters S1, S2, and S3 of the reflected light change when the exposure amount changes, and when the focus position changes, the Stokes parameters S1 and S3 of the reflected light change relatively greatly, and the Stokes parameters change. The parameter S2 does not change much (see FIGS. 3A and 3B). For this reason, since it is possible to determine the conditions of the exposure amount and the focus position independently from only the Stokes parameters S2 and S3, it is only necessary to obtain the Stokes parameters S2 and S3.
- an FEM wafer is used as the conditioned wafer 10a.
- all the shots formed on the wafer are formed under appropriate exposure conditions (hereinafter referred to as good products). (Referred to as a wafer).
- the shot average value of the Stokes parameters of the non-defective wafer is calculated in step 118 of FIG.
- a difference between shot average values of shots having the same position on the wafer between the shot on the FEM wafer and the shot on the non-defective wafer is calculated.
- the first apparatus condition with high dose sensitivity and low focus sensitivity and the focus sensitivity are high, A second apparatus condition with low dose sensitivity is determined. Note that it is not necessary to calculate the difference between shot average values, and a ratio or the like may be calculated.
- the Stokes parameters S2 and S3 are used for the evaluation of the exposure amount, and the Stokes parameter S3 is used for the evaluation of the focus position in order to obtain the exposure conditions of the pattern for the device that is actually a product.
- the type of Stokes parameter to be used is not limited to this.
- the Stokes parameters S1 and S2 may be used for the evaluation of the exposure amount
- the Stokes parameters S1 and S3 may be used for the evaluation of the focus position.
- the Stokes parameter S1 changes in response to changes in both the exposure amount and the focus position. Therefore, the determination of the exposure amount is at least selected from the Stokes parameters S1 (or S1, S2, S3).
- the focus position may be determined using the Stokes parameter S1 (or at least one parameter selected from S1 and S3).
- the change in the elliptically polarized light from the wafer surface with respect to each change in the exposure amount and the focus position does not change as shown in FIG. 3, the change in the Stokes parameter with respect to the change in the exposure amount, and the change in the focus position
- the type of the Stokes parameter may be selected as appropriate so that the first device condition and the second device condition are obtained based on the change of the Stokes parameter with respect to the change.
- the template stored in the storage unit 85 in step 132 and step 134 is a table of arbitrary Stokes parameter values corresponding to arbitrary exposure conditions, but the template is a table.
- a curve or an approximate expression obtained by mathematically fitting an arbitrary function of an arbitrary Stokes parameter value for an arbitrary exposure condition may be used.
- curves BS21 and BS32 indicating changes in Stokes parameters S2 and S3 with respect to the exposure amount obtained under the first apparatus condition (here, apparatus conditions A and B) are represented as template TD1.
- TD2 or approximate expressions of the curves BS21, BS32 may be used as the templates TD1, TD2.
- the curve CS32 obtained under the second apparatus condition here, apparatus condition A
- the template TF1 the approximate expression of the curve CS32 may be used as the template TF1.
- an appropriate range EG an exposure amount range EB1 exceeding the appropriate range, and an exposure amount range EB2 lower than the appropriate range are set.
- this two-dimensional distribution may be used as a template for quality determination.
- the values of the parameters S2 and S3 may be represented by (S2, S3), and the non-defective product range EG may be approximately inside a circle having the following center coordinates (sa, sb) and radius sr.
- the exposure amount of the pixel is within the appropriate range, the appropriate range above the appropriate range, or the appropriate range from the Stokes parameters S2 and S3 (S2x, S3x). It may be determined whether the exposure amount falls within the range, and information on the determination result may be supplied to the control unit 80.
- the difference from the appropriate exposure amount Dbe of the measurement value Dx and the difference from the proper focus position Zbe of the measurement value Fy may not be calculated.
- various calculation methods such as the measurement value Dx and the measurement value Fy calculated in Step 158 and Step 160, the ratio of the measurement value Dx to the appropriate exposure amount Dbe, and the ratio of the measurement value Fy to the appropriate focus position Zbe are used. It may be used. Further, the determination result of these exposure conditions may not be displayed on a display device (not shown).
- the exposure amount and the focus position are determined as the exposure conditions.
- the exposure conditions the exposure light wavelength, the illumination conditions (for example, the coherence factor ( ⁇ value), the projection optical system in the exposure apparatus 100 are determined.
- the determination of the above embodiment may be used to determine the numerical aperture of PL or the temperature of the liquid during immersion exposure.
- the inspection apparatus 1 in FIG. 1A is used to determine the processing conditions of a device manufacturing system (not shown).
- the processing conditions of a wafer on which a repetitive pattern with a fine pitch is formed is determined by a so-called spacer double patterning method (or sidewall double patterning method).
- the device manufacturing system in this embodiment includes an exposure apparatus 100, a thin film forming apparatus (not shown), and an etching apparatus (not shown).
- a plurality of resists are applied to the surface of, for example, the hard mask layer 17 of the wafer 10d by applying resist, exposing the pattern with the exposure apparatus 100, and developing.
- a repetitive pattern 12 in which the line portions 2A of the pattern are arranged at a pitch P is formed.
- the pitch P is close to the resolution limit of the exposure apparatus 100.
- the line portion 2A is halved by using etching (so-called slimming) by an etching apparatus (not shown).
- the spacer layer 18 is deposited so as to cover the line portion 12A with a thin film forming apparatus (not shown).
- the spacer layer 18 of the wafer 10d is etched by a predetermined thickness by an etching apparatus (not shown), and then only the line portion 12A is removed by the etching apparatus, 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.
- 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.
- 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 1 ⁇ 2 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.
- the pitch of the repeated pattern must be equal to or greater than 1 ⁇ 2 of the wavelength ⁇ of the illumination light ILI of the inspection 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. 13A, the diffraction inspection becomes increasingly difficult. Further, as in the case of FIG. 13D, with respect to 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.
- the processing conditions of the repeated pattern 17B can be determined with high accuracy.
- the processing conditions of the repeated pattern 17B in the operation of selecting a plurality of apparatus conditions used when determining the processing conditions from the Stokes parameters of the reflected light from the pattern 17B of the wafer 10d (conditioning), it is repeated by a device manufacturing system (not shown).
- processing conditions for the pattern 17B an etching amount te of the spacer layer 18 and a deposition amount ts (thin film deposition amount) of the spacer layer 18 in FIG. 13B are assumed.
- the Stokes parameters used for evaluating the deposition amount ts and the etching amount te of the spacer layer 18 are S2 and S3 as in the first embodiment. Note that the use of the Stokes parameters S2 and S3 for the evaluation of the deposition amount ts and the etching amount te of the spacer layer 18 is merely an example. In this embodiment, the deposition amount ts and the etching amount te of the spacer layer 18 are evaluated.
- the type of the Stokes parameter to be used is selected in consideration of the magnitude of the change in each Stokes parameter S0 to S3 with respect to the change in the deposition amount ts and the magnitude of the change in each Stokes parameter S0 to S3 with respect to the change in the etching amount te. May be. That is, a Stokes parameter having a large change with respect to the change in the deposition amount ts and a small change with respect to the change in the etching amount te is selected from S0 to S3, and the change with respect to the change in the etching amount te is large. A Stokes parameter with a small value may be selected from S0 to S3.
- a conditioned wafer is created in step 102A of FIG.
- 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 inspection apparatus 1 in FIG. Then, the operations of Steps 102A to 130A are executed in each of the plurality of conditionally adjusted wafers.
- each conditionally adjusted wafer (not shown) is transferred onto the stage 5 of the inspection apparatus 1.
- the control unit 80 reads out a plurality of device conditions from the recipe information in the storage unit 85.
- the wavelength of the illumination light ILI is set to ⁇ 1 (step 104A), the incident angle ⁇ 1 is set to ⁇ 1 (step 106A), and the rotation angle of the polarizer 26 is set to ⁇ 1 (step 108A).
- the rotation angle of the quarter wavelength plate 33 is set to an initial value (step 110B). Then, under this apparatus condition, the illumination light ILI is irradiated onto the surface of the conditionally adjusted wafer, and the imaging device 35 picks up an image of the conditionally adjusted wafer and outputs an image signal to the image processing unit 40 (step 112B). . Next, it is determined whether or not the quarter wavelength plate 33 is set to all angles (step 114B).
- the quarter wavelength plate 33 is set to, for example, about 1.41.
- the angle is rotated by ° (an angle obtained by dividing the rotatable angle range 360 ° of the quarter-wave plate 33 by 256) (step 116B), and the process returns to step 112B to capture an image of the conditionally adjusted wafer.
- step 112B By repeating step 112B until the angle of the quarter wavelength plate 33 is rotated by 360 ° in step 114B, images of 256 wafers are picked up corresponding to different rotation angles of the quarter wavelength plate 33.
- the operation shifts from step 114B to step 118B, and the image processing unit 40 performs Stokes parameters S0 to S3 for each pixel of the image sensor 35b from the obtained digital images of 256 wafers by the above-described rotational phase shift method.
- the Stokes parameters S0 to S3 are output to the first calculation unit 60a of the inspection unit 60.
- the first calculation unit 60a obtains an average value of the Stokes parameters for each wafer (hereinafter referred to as a wafer average value) as an example. 2 is output to the calculation unit 60b and the storage unit 85.
- the reason why the wafer average value is obtained in this way is that the processing conditions (here, the deposition amount of the spacer layer and the etching amount of the spacer layer) are the same in each conditionally adjusted wafer of this embodiment.
- the Stokes parameters of pixels corresponding to all shots SAn (see FIG. 6B) excluding the scribe line area SL of the conditionally adjusted wafer may be calculated, and the calculation result may be averaged within the wafer.
- the second arithmetic unit 60b of the inspection unit 60 uses the Stokes against the change in the deposition amount ts of the spacer layer.
- the template determined as the first apparatus condition is stored in the storage unit 85 as a table in which the value of the Stokes parameter S2 with respect to the change in the deposition amount ts of the spacer layer obtained under the first apparatus condition is tabulated (step 132A). Further, in the second arithmetic unit 60b, an apparatus condition in which the etching sensitivity of the Stokes parameter S3 is high and the deposition amount sensitivity is low is determined as the second apparatus condition, and the change in the etching amount te obtained under the second apparatus condition is determined. A template in which the value of the Stokes parameter S3 is tabulated is stored in the storage unit 85 (step 134A).
- the change of the Stokes parameter S2 (wafer average value) measured under a certain apparatus condition D with respect to the spacer layer deposition amount ts is a curve BS24 of FIG. 13E, and the change with respect to the etching amount te. Is a curve CS24 in FIG.
- the change of the Stokes parameter S3 measured under a certain apparatus condition E with respect to the deposition amount ts of the spacer layer is the curve BS34 of FIG. 13E
- the change with respect to the etching amount te is the curve of FIG. 13F.
- the Stokes parameters S2 and S3 are standardized values, and the curve BS24 and the like are data shown for convenience of explanation.
- the apparatus conditions of the inspection apparatus 1 are curves (changes in Stokes parameters with respect to changes in processing conditions) of only two types (apparatus conditions D and apparatus conditions E) from the apparatus condition ⁇ .
- the apparatus condition D is the first apparatus condition in which the deposition amount sensitivity of the Stokes parameter S2 is high and the etching sensitivity is low.
- the apparatus condition E is a second apparatus condition in which the deposition amount sensitivity of the Stokes parameter S3 is high and the etching sensitivity is low. Accordingly, data obtained by tabulating values indicating the change in the Stokes parameter S2 with respect to the deposition amount ts of the spacer layer obtained under the first apparatus condition (here, apparatus condition D) is used as a first template for the deposition amount of the spacer layer. It is stored in the storage unit 85.
- the condition determination for obtaining the first and second apparatus conditions used when determining the processing conditions of the wafer pattern 17B is completed.
- the Stokes parameter is measured by the inspection apparatus 1 for the wafer 10d on which the repeated pattern 17B is formed in the actual device manufacturing process, and the spacer layer deposition amount ts and the spacer layer etching amount te in the processing conditions are measured. Determine. Therefore, in step 150A of FIG. 15, the manufactured wafer 10d is loaded onto the stage 5 of the inspection apparatus 1 of FIG. 1A via an alignment mechanism (not shown). And the control part 80 reads the 1st and 2nd apparatus conditions determined by said condition determination from the recipe information of the memory
- the apparatus condition is set to the first apparatus condition (apparatus condition D) in which the Stokes parameter S2 is highly sensitive to changes in the amount of deposited spacer layers (step 152A), and the rotation angle of the quarter-wave plate 33 is set to the initial value. (Step 110C). Then, the illumination light ILI is irradiated onto the wafer surface, and the imaging device 35 outputs an image signal of the wafer surface to the image processing unit 40 (step 112C). Next, until it is determined in step 114C that the angle of the quarter-wave plate 33 is rotated by 360 °, the quarter-wave plate 33 is rotated by, for example, 360 ° / 256 (step 116C), and an image of the wafer 10d is captured. By repeating the operation of (step 112C), 256 images of the wafer surface are captured corresponding to different rotation angles of the quarter-wave plate 33.
- step 118C the image processing unit 40 obtains the Stokes parameter S2 for each pixel of the image pickup device 35 from the obtained digital images of 256 wafers by the above-described rotational phase shift method.
- This Stokes parameter is output to the first calculation unit 60a of the inspection unit 60, and an average value (shot average value) of the Stokes parameters for each shot is obtained by the first calculation unit 60a and stored in the third calculation unit 60c and the storage unit 85. Is output.
- the operation shifts from step 154A to step 156A to set the device condition to the second device condition (device condition E) and then step. Return to 110C.
- Steps 110C to 118C are repeated, and the shot average value of the Stokes parameter S3 is obtained and stored under the second apparatus condition. Thereafter, the operation proceeds to step 158A.
- the third calculation unit 60c of the inspection unit 60 stores the first Stokes parameter S2 value (referred to as S2Ax) for each pixel obtained in the first apparatus condition stored in step 132A described above.
- the deposition amount tsx of the spacer layer is obtained in light of the template.
- the distribution of the difference (error) from the optimum value of the deposited amount of the spacer layer of the measured value tsx is supplied to the control unit 80 and further displayed on a display device (not shown) as necessary.
- step 160A the third calculation unit 60c compares the value of the Stokes parameter S3 for each pixel obtained under the second apparatus condition (referred to as S3Ay) with the second template stored in step 134A, The etching amount tey is obtained.
- the distribution of the difference (error) from the optimum value of the etching amount of the measured value tey is supplied to the control unit 80 and further displayed on a display device (not shown) as necessary.
- step 158A and step 160A of the present embodiment the difference from the optimum values of the measurement values tsx and tey may not be calculated.
- the ratio of the measured values tsx and tey calculated in step 158A and step 160A to the optimum value may be obtained.
- an error distribution (spacer layer deposition amount) of the spacer layer deposition amount on the entire surface of the wafer is transferred from the signal output unit 90 to a control unit (not shown) such as a host computer of the device manufacturing system under the control of the control unit 80.
- a control unit such as a host computer of the device manufacturing system under the control of the control unit 80.
- the error distribution of the etching amount of the spacer are provided (step 162A).
- the control unit (not shown) of the device manufacturing system for example, when the uneven deposition amount of the spacer layer exceeds a predetermined appropriate range, the spacer layer is deposited on the thin film forming apparatus (not shown). Send control information to correct the amount of unevenness.
- control unit When the unevenness of the etching amount exceeds a predetermined appropriate range, the control unit sends control information to the etching apparatus (not shown) so as to correct the unevenness of the etching amount.
- the control unit sends control information to the etching apparatus (not shown) so as to correct the unevenness of the etching amount.
- the information on the unevenness of the etching amount on the entire surface of the wafer 10 and the unevenness of the deposition amount of the spacer layer is not a signal output unit 90 but a control unit (not shown) of the device manufacturing system, and a thin film forming apparatus (not shown). And may be directly supplied to an individual control unit of an etching apparatus (not shown). Further, it may be supplied to a host computer (not shown) of the device manufacturing system.
- the etching amount in the etching apparatus used at the time of formation can be determined with high accuracy by removing the influence of the deposition amount of the spacer. Furthermore, the amount of spacer deposition in the thin film forming apparatus can be determined or estimated with high accuracy by removing the influence of the etching amount.
- the inspection apparatus 1 and the inspection method of this embodiment repeat the unevenness provided on the wafer 10d by processing under a plurality of processing conditions including the deposition amount of the spacer layer and the etching amount of the spacer layer.
- This is an apparatus and method for determining the processing conditions of the pattern 17B.
- the inspection apparatus 1 includes a stage 5 that can hold the wafer 10d on which the pattern 17B is formed, an illumination system 20 that illuminates the surface of the wafer 10d with linearly polarized illumination light ILI (polarized light), and the wafer 10.
- ILI linearly polarized illumination light
- the calculation unit 50 obtains the apparatus conditions of the inspection apparatus 1 for determining the processing conditions of the pattern 17B to be inspected based on the Stokes parameters of the light emitted from the conditionally adjusted wafer on which the pattern 17B is formed under the known processing conditions. Based on Stokes parameters of light emitted from the surface of the wafer 10d under the apparatus conditions obtained by the calculation unit 50. It is determined the processing conditions of over emissions 17B.
- steps 112B and 112C for illuminating the surface of the wafer 10d on which the pattern 17B is formed with polarized light and receiving light emitted from the surface of the wafer 10d, and Stokes of this light Steps 118B and 118C for detecting parameters, and apparatus conditions (inspection conditions) for determining the processing conditions of the inspection target pattern 17B formed on the surface of the inspection target wafer 10d are as follows.
- the processing conditions of the pattern 17B based on the steps 132A and 134A obtained based on the Stokes parameters of the light emitted from the formed conditionally adjusted wafer and the Stokes parameters of the light emitted from the surface of the wafer 10d under the obtained apparatus conditions.
- Steps 158A and 160A are determined.
- the spacer layer deposition amount and the spacer layer among the plurality of processing conditions can be estimated or determined with high accuracy while the influence of other processing conditions is suppressed. Also, it is not necessary to use a separate pattern for evaluation, and the processing conditions can be determined by detecting light from the wafer on which the device pattern that will be the product is actually formed. Conditions can be determined efficiently and with high accuracy.
- the wafer may be illuminated with circularly polarized light as in the first embodiment described above.
- the light from the light source unit 22 is converted into circularly-polarized light by the polarizer 26 and the half-wave plate to illuminate the wafer.
- 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).
- a light source that emits linearly polarized light or elliptically polarized light can be used as the light source unit 22 .
- the diffracted light from the surface of the wafer 10 may be received by the light receiving system 30, and the exposure conditions may be evaluated based on the calculated Stokes parameters.
- the control unit 80 controls the light receiving system 30 so that the light receiving system 30 receives the diffracted light from the surface of the wafer 10 based on known diffraction conditions.
- the plurality of apparatus conditions in the present embodiment include the rotation angle of the analyzer 32 (the direction of the transmission axis of the analyzer 32), the rotation angle of the stage 5 (the direction of the wafer), and the like. Can be included.
- the angle of the quarter-wave plate 33 is set to at least four different angles, and at least 4 An image of the single wafer 10d may be taken.
- the template stored in the storage unit 85 in step 132A and step 134A in this embodiment is data in which the values of arbitrary Stokes parameters corresponding to arbitrary processing conditions are tabulated, but the template is limited to a table. It will never be.
- a curve obtained by mathematically fitting a change in an arbitrary Stokes parameter with respect to an arbitrary processing condition using an arbitrary function see, for example, FIGS. 13E and 13F) or an approximate expression may be used.
- the apparatus condition (apparatus condition D) is determined based on one type of Stokes parameter S2 as the first apparatus condition.
- Stokes parameters S2 and S3 are used.
- the apparatus conditions may be determined based on a plurality of types of Stokes parameters.
- the plurality of types of Stokes parameters are calculated by a desired calculation formula so that the difference between the etching sensitivity and the deposition amount sensitivity of the target types of Stokes parameters becomes larger (the same calculation is performed for the second apparatus condition as well). You may calculate with a formula).
- arithmetic expressions such as a sum and a sum of squares can be used as the arithmetic expressions of the plurality of types of Stokes parameters.
- the exposure conditions are evaluated under the apparatus conditions of the inspection apparatus 1 obtained using a desired arithmetic expression, so that the accuracy is higher than the method of obtaining the apparatus conditions corresponding to one type of Stokes parameter. It becomes possible to evaluate the processing conditions.
- At least one arbitrary parameter selected from the Stokes parameters S1, S2, and S3 can be used.
- the processing conditions in the present embodiment can include conditions that may be changed as processing conditions in the etching apparatus and the thin film forming apparatus in addition to the etching amount and the spacer deposition amount.
- the deposition amount of the hard mask layer 17 or the etching amount (slimming amount) when forming the line portion 12A may be used.
- the processing conditions of the etching apparatus may be etching time and temperature in the etching apparatus, and the processing conditions of the thin film forming apparatus may be the deposition time and temperature of the thin film in the thin film forming apparatus.
- the processing conditions are not limited to the etching apparatus and the thin film forming apparatus, and may be, for example, processing conditions in a coater / developer that forms a resist on a wafer and develops the resist after exposure by an exposure apparatus.
- the processing conditions of the coater / developer may be the baking temperature and time of the resist applied to the wafer, the developing time of the resist after exposure, and the liquid temperature of the developer.
- step 158A and step 160A of the present embodiment the difference from the appropriate value of the deposition amount of the measured value tsx and the difference from the appropriate value of the etching amount of the measured value tey may not be calculated.
- various calculation methods such as the measurement value tsx and the measurement value tey calculated in step 158A and step 160A, the ratio of the measurement value Dx to the deposition amount of the appropriate spacer layer, and the ratio of the measurement value Fy to the appropriate etching amount May be used.
- the determination result of these exposure conditions may not be displayed on a display device (not shown).
- FIG. 16B shows an exposure apparatus 100A according to this embodiment.
- an exposure apparatus 100A holds an illumination system ILS that illuminates the reticle R with exposure light, as disclosed in, for example, US Patent Application Publication No. 2007/242247, and the reticle R.
- the exposure apparatus 100A of the present embodiment includes an on-body inspection apparatus 1A that measures the Stokes parameters of the reflected light from the pattern of the wafer 10 and determines the exposure condition of the pattern.
- FIG. 16A shows an inspection apparatus 1A according to this embodiment.
- an inspection apparatus 1A includes a stage 5A that holds the wafer 10 and moves 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 portion (test area) of the surface (ie, the wafer surface) of the wafer 10 supported by the stage 5A with the illumination light ILI, and the wafer that has been irradiated with the illumination light ILI.
- a light receiving system 30A that receives the reflected light ILR from the surface and forms an image of the region under test, a two-dimensional image sensor 47 that detects the image, and an image signal output from the image sensor 47
- An image processing unit 40A that obtains a condition that defines the state of polarization, an arithmetic unit 50A that determines exposure conditions (processing conditions) of the pattern on the wafer surface using information on the conditions, and controls the operation of the entire apparatus.
- control And includes a 80A, the.
- stage 5A is also used as wafer stage WST.
- 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, a polarizer 26A for making the illumination light linearly polarized light, and an aperture 43Aa are provided on 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).
- 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. 16A).
- Imaging lens 4 It It has a C, and.
- the transmission axis of the polarizer 26 ⁇ / b> A 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.
- the opening 43Ba of the light receiving side aperture stop 43B is symmetric with respect to the optical axis with respect to the opening 43Aa of the illumination side aperture stop 43A so that the regular reflection light ILR from the wafer 10 is received by the light receiving system 30A.
- the illumination light from the illumination unit 21 that has passed through the aperture 43Aa of the stop 43A is installed at a position where the light reflected from the test region of the wafer 10 is transmitted.
- a variable shutter mechanism made of a liquid crystal display element may be used instead of the aperture plates 43A and 43B.
- the drive unit 46 passes through the center of the incident surface 33Aa through which light enters the quarter-wave plate 33A and is parallel to the Z-axis (that is, the optical axis AXD) as a rotation axis.
- the analyzer 32A is rotated individually.
- the inspection apparatus 1A includes a drive unit (not shown) that rotates the polarizer 26A around the axis parallel to the X axis (that is, the optical axis AXI) passing through the center of the incident surface 26Aa where the light beam enters the polarizer 26A.
- the direction of the transmission axis of the analyzer 32A can be set in a direction orthogonal to the direction of the transmission axis of the polarizer 26A (ie, crossed Nicols).
- the rotation angle of the quarter-wave plate 33A can be controlled within a range of 360 ° by the drive unit 46 based on a command from the control unit 80A.
- Conditions for defining the polarization state of the reflected light from the wafer 10 as in the first embodiment by processing a plurality of images of the test region of the wafer 10 obtained while rotating the quarter-wave plate 33A.
- the Stokes parameter can be obtained for each pixel, for example.
- the wavelength of the illumination light ILI is switched by the illumination unit 21, the incident angle (reflection angle) of the illumination light ILI with respect to the wafer 10 is switched by driving the aperture plates 43A and 43B, and the rotation angle of the polarizer 26A
- the apparatus condition when measuring the Stokes parameter, measuring the distribution of the Stokes parameter in the test area on the surface of the wafer 10 and moving another test area of the wafer 10 to the illumination area of the illumination light ILI by the stage 5A.
- the Stokes parameter of the reflected light from the pattern on the entire surface of the wafer 10 is measured, and the exposure condition at the time of forming the pattern can be determined from the measurement result.
- the light from the repetitive pattern on the wafer surface is detected using the inspection apparatus 1A, and the exposure conditions (here, the exposure amount and the focus position) of the exposure apparatus 100A used when forming the pattern are detected.
- the exposure conditions here, the exposure amount and the focus position
- An example of a method for determining the above will be described with reference to the flowchart of FIG.
- An example of a method for obtaining the apparatus conditions (inspection conditions) in advance for the determination will be described with reference to the flowchart of FIG.
- These operations are controlled by the control unit 80A.
- steps corresponding to the steps in FIGS. 4 and 5 are denoted by similar reference numerals, and description thereof is omitted or simplified.
- a condition-adjusted wafer 10a made of a so-called FEM wafer is developed by exposing and developing the exposure amount and the focus position in a matrix. Is created.
- the control unit 80A reads a plurality of apparatus conditions from the recipe information in the storage unit 85A.
- the wavelength ⁇ of the illumination light ILI is any one of the above ⁇ 1, ⁇ 2, and ⁇ 3, and the incident angle of the illumination light ILI to the wafer (the emission angle of the reflected light from the wafer) is 15 °. 30 °, 45 °, and 60 °, and the rotation angle of the polarizer 26A is assumed to be set to a plurality of angles at intervals of about 5 °, for example, with the crossed Nicol state as the center.
- the device condition can also be expressed by the condition ⁇ (nmj).
- the wavelength of the illumination light ILI is set to ⁇ 1 (step 104B), the position of the opening 43Aa of the illumination system aperture stop 43A is adjusted, and the incident angle of the illumination light ILI is set to ⁇ 1 (also together)
- the position of the aperture 43Ba of the light receiving system aperture stop 43B is adjusted to set the light receiving angle of the light receiving system 30A (step 106B)
- the rotation angle of the polarizer 26A is set to ⁇ 1 (step 108B), and 1 ⁇ 4.
- the rotation angle of the wave plate 33A (phase plate) is set to an initial value (step 110D).
- the illumination light ILI is irradiated onto the surface of the conditionally adjusted wafer 10a, and the image sensor 47 picks up an image of the conditionally adjusted wafer 10a and outputs an image signal to the image processing unit 40A (step). 112D).
- it is determined whether or not an image of the entire surface of the wafer 10a has been captured (step 166). If there is a part that has not been captured, the stage 5A is driven in the X direction and / Y direction in step 168 to After moving the surface of the surface of the surface that has not been imaged to the illumination area (observation area) of the illumination light ILI, the process returns to step 112D to capture an image of the wafer 10a.
- steps 168 and 112D are repeated until an image of the entire surface of the wafer 10a is captured. After the image of the entire surface of the wafer 10a is captured, the operation proceeds to step 114D, and it is determined whether or not the quarter wavelength plate 33A is set to all angles.
- the quarter-wave plate 33A is rotated by, for example, 360 ° / 256 (step 116D), and the process returns to step 112D to return the conditionally adjusted wafer.
- the image of 10a is taken.
- steps 112D, 166, and 168 until the angle of the quarter-wave plate 33A is rotated by 360 ° in step 114D, the entire surface of 256 wafers corresponding to different rotation angles of the quarter-wave plate 33A is obtained. An image is taken.
- step 114D the operation proceeds from step 114D to step 118D, and the image processing unit 40A performs Stokes parameters S0 to S3 for each pixel of the image sensor 47 from the obtained digital images of 256 wafers by the above-described rotational phase shift method.
- the Stokes parameters S0 to S3 are output to the first calculation unit of the inspection unit 60A, and the first calculation unit obtains, as an example, an average value for each shot of the Stokes parameter (that is, shot average value). Output to the storage unit 85A.
- the aperture 43Aa of the illumination system aperture stop 43A is moved, the incident angle is set to ⁇ 2 (step 126B), and the process returns to step 108B.
- the Stokes parameters for each pixel of the image on the wafer surface are calculated by the rotational phase shifter method (steps 108B to 120B).
- the process proceeds from step 124B to step 128B to determine whether or not the wavelengths ⁇ of the illumination light ILI are set to all wavelengths. If it is determined that all the wavelengths are not set, the illumination unit 21 changes the wavelength ⁇ to ⁇ 2 (step 130B), and the process returns to step 106B.
- the Stokes parameters S1, S2, and S3 of the reflected light change when the exposure amount changes, and when the focus position changes, the Stokes parameters S1 and S3 of the reflected light are compared.
- the Stokes parameter S2 does not change much.
- the exposure amount is determined using the Stokes parameter S2 and / or S3, and the focus position is determined using the Stokes parameter S3.
- the second arithmetic unit of the inspection unit 60A is the first apparatus with high dose sensitivity and low focus sensitivity of the Stokes parameters S2 and S3.
- the conditions are determined, and data obtained by tabulating the first apparatus conditions and the values of the Stokes parameters S2 and S3 corresponding to the exposure amounts obtained under the apparatus conditions are stored in the storage unit 85 as a template (step) 132B).
- the second calculation unit determines a second device condition in which the focus sensitivity of the Stokes parameter S3 is high and the dose sensitivity is low, and the second device condition and each focus value obtained under the device condition are determined.
- Data that tabulates the value of the corresponding Stokes parameter S3 is stored in the storage unit 85 as a template (step 134B).
- the first device condition in which the dose sensitivity of the Stokes parameter S2 is high and the focus sensitivity is low is the device condition A corresponding to the curve BS21 in FIG. 10A and the curve CS21 in FIG. is there.
- the first device condition in which the dose sensitivity of the Stokes parameter S3 is high and the focus sensitivity is low is a device condition B corresponding to the curve BS32 in FIG. 10C and the curve CS32 in FIG.
- the second device condition in which the focus sensitivity of the Stokes parameter S3 is high and the dose sensitivity is low is a device condition A corresponding to the curve CS31 in FIG. 10D and the curve BS31 in FIG.
- the data obtained by tabulating the value of the Stokes parameter S2 corresponding to each exposure amount obtained under the first apparatus condition is a curve indicating the change in the Stokes parameter S2 with respect to the template TD1.
- a table based on BS21) is stored in the storage unit 85A.
- data obtained by tabulating the value of the Stokes parameter S3 corresponding to each exposure amount obtained under the first apparatus condition is stored in the storage unit 85A as the template TD2.
- data obtained by tabulating the value of the Stokes parameter S3 corresponding to each focus value obtained under the second apparatus condition is stored in the storage unit 85A as the template TF1.
- the apparatus condition (inspection condition) the first apparatus condition (apparatus conditions A and B) and the second apparatus condition (apparatus condition B) different from the first apparatus condition are included. include.
- the condition determination for obtaining the first and second apparatus conditions used when determining the wafer exposure conditions is completed.
- the reflection from the wafer surface is performed using the two apparatus conditions obtained by the above-described condition determination by the inspection apparatus 1A.
- the exposure amount and the focus position in the exposure conditions of the exposure apparatus 100A are determined as follows. As shown in FIG. 18, first, a wafer 10 that has the same shot arrangement as that in FIG. 6A and is an actual product coated with a resist is transferred to the exposure apparatus 100A, and each shot of the wafer 10 is shot by the exposure apparatus 100A.
- the exposure conditions at this time are the optimum exposure amount determined in accordance with the reticle with respect to the exposure amount in all shots, and the optimum focus position with respect to the focus position.
- step 150B of FIG. 18 the exposed and developed wafer 10 is loaded onto stage 5A (here, wafer stage WST) of inspection apparatus 1A of FIG. 16 via an alignment mechanism (not shown).
- the control unit 80A reads the first and second device conditions determined by the above-described condition determination from the recipe information in the storage unit 85A.
- the apparatus condition is set to the first apparatus condition (in this case, the apparatus condition A for the Stokes parameter S2) in which the dose sensitivity of the Stokes parameters S2 and S3 is high (step 152B), and the rotation of the quarter wavelength plate 33A is performed.
- the corner is set to an initial value (step 110E).
- the illumination light ILI is irradiated onto the wafer surface, and the image sensor 47 outputs an image signal of the wafer surface to the image processing unit 40A (step 112E).
- step 166A it is determined whether or not an image of the entire surface of the wafer 10 has been captured. If there is a portion that has not been captured, the stage 5A is driven in the X direction and / Y direction in step 168A, After moving the part of the surface not imaged to the illumination area (observation area) of the illumination light ILI, the process returns to step 112E and an image of the wafer 10 is imaged. Steps 168A and 112E are repeated until an image of the entire surface of the wafer 10 is captured. After the image of the entire surface of the wafer 10 is captured, the operation proceeds to step 114E, and it is determined whether or not the quarter wavelength plate 33A is set to all angles.
- step 116E the quarter-wave plate 33A is rotated by, for example, 360 ° / 256 (step 116E), and the process proceeds to step 112E, where the image of the wafer 10 is obtained. Take an image.
- steps 112E, 166A, and 168A the entire surface of 256 wafer surfaces corresponding to different rotation angles of the quarter-wave plate 33A. are captured.
- step 118E the image processing unit 40A obtains Stokes parameters S2 and S3 for each pixel of the image sensor 47 from the obtained digital images of 256 wafers by the above-described rotational phase shift method.
- This Stokes parameter is output to the first calculation unit of the inspection unit 60A, and the first calculation unit obtains an average value (that is, shot average value) of the Stokes parameter for each shot and stores it in the third calculation unit and the storage unit 85A. Output.
- it is determined whether or not the determination is made for all the apparatus conditions (step 154B). If not all the apparatus conditions for inspection are set, another apparatus condition is set in step 156B, and then the process proceeds to step 110E. Transition.
- the device condition B since the first device condition for the Stokes parameter S3 is the device condition B, the device condition B is set here. Thereafter, steps 110E to 118E are repeated, and the shot average value of the Stokes parameter (S3 in this case) is obtained and stored under the apparatus condition B. Since the second apparatus condition is the same as the apparatus condition A here, the Stokes parameter S3 obtained when the apparatus condition A is set is used as the Stokes parameter obtained under the second apparatus condition. Normally, there is a possibility that steps 110E to 118E are executed in a state where another device condition is set as the second device condition. When the determination under the first and second device conditions is completed in step 154B, the operation proceeds to step 158B.
- the third calculation unit of the inspection unit 60A stores the values of the Stokes parameters S2 and S3 for each pixel (referred to as S2x and S3x) obtained in the first apparatus condition in step 132B described above.
- Exposure amounts Dx1 and Dx2 are obtained in light of templates TD1 and TD2. Actually, the exposure amounts Dx1 and Dx2 are almost the same value.
- the average value of the exposure doses Dx1 and Dx2 may be used as the exposure dose measurement value Dx.
- the distribution of the difference (error) from the optimum exposure amount Dbe of the measured value Dx is supplied to the control unit 80A and further displayed on a display device (not shown) as necessary.
- the third calculation unit of the inspection unit 60A stores the value of the Stokes parameter S3 for each pixel (referred to as S3y) obtained in the second apparatus condition in step 134B of FIG. 11B.
- the focus value Fy is obtained in light of the template TF1.
- the distribution of the difference (error) of the measured value Fy from the optimum focus position Zbe is supplied to the control unit 80A and further displayed on a display device (not shown) as necessary.
- the exposure amount error distribution (exposure amount unevenness) and the focus position error distribution (delay amount) of the entire surface of the wafer 10 Information on the distribution of the focus amount is provided (step 162B).
- the exposure condition of the exposure amount and / or the focus position is determined. In order to correct this, for example, correction of the width distribution in the scanning direction of the illumination area at the time of scanning exposure is performed. As a result, the error of the exposure amount distribution and the defocus amount are reduced during the subsequent exposure.
- the exposure apparatus 100A exposes the wafer under the corrected exposure conditions.
- the inspection apparatus 1 ⁇ / b> A and the inspection method according to the present embodiment set the exposure conditions of the concave / convex repeated pattern 12 provided on the wafer 10 by exposure under a plurality of exposure conditions including the exposure amount and the focus position. An apparatus and method for determination.
- the inspection apparatus 1A includes a stage 5A that can hold the wafer 10 on which the pattern 12 is formed, an illumination system 20A that illuminates the surface of the wafer 10 with linearly polarized illumination light ILI (polarized light), and the wafer 10. Formed on the surface of the wafer 10 to be inspected, and the imaging device 47 and the image processing unit 40A that receive the light emitted from the surface of the light and detect the Stokes parameters S1 to S3 (conditions for defining the polarization state) of the light.
- ILI linearly polarized illumination light
- a calculation unit 50A that determines an apparatus condition of the inspection apparatus 1A for determining the exposure condition of the pattern to be inspected based on a Stokes parameter of light emitted from the conditionally adjusted wafer 10a on which the pattern is formed under a known exposure condition; Based on the Stokes parameters of the light emitted from the surface of the wafer 10 under the apparatus conditions determined by the calculation unit 50A. It is determined the turn of the exposure conditions.
- the inspection method of this embodiment includes steps 112D and 112E for illuminating the surface of the wafer 10 on which the pattern 12 is formed with polarized light and receiving light emitted from the surface of the wafer 10, and Stokes of this light.
- Steps 118D and 118E for detecting parameters, and apparatus conditions (inspection conditions) for determining the exposure conditions of the pattern 12 to be inspected formed on the surface of the wafer 10 to be inspected are as follows. Steps 132B and 134B obtained based on the Stokes parameters of the light emitted from the formed conditional wafer 10a and the exposure of the pattern 12 based on the Stokes parameters of the light emitted from the surface of the wafer 10 under the obtained apparatus conditions. Steps 158B and 160B for determining conditions are included.
- the exposure amount among the plurality of exposure conditions And the focus position can be estimated or determined with high accuracy while the influence of other exposure conditions is suppressed.
- the first and second apparatus conditions used during the inspection of the exposure conditions are patterns that are formed by combining the known first and second exposure conditions (exposure amount and focus position).
- the Stokes parameters S2 and S3 of the light emitted from the conditioned wafer 10a are changed so that the change of the first and second exposure conditions (sensitivity) is larger than that of the other exposure condition. is there. Therefore, the first and second exposure conditions can be determined while suppressing the influence of other exposure conditions.
- the exposure system of the present embodiment includes an exposure apparatus 100A (exposure unit) having a projection optical system that exposes a pattern on the surface of the wafer, and the inspection apparatus 1A of the present embodiment, and an arithmetic unit of the inspection apparatus 1A.
- the exposure conditions in the exposure apparatus 100A are corrected according to the first and second exposure conditions determined by 50A.
- the first and second exposure conditions of the wafer are determined using the inspection method of the present embodiment (steps 150B to 160B), and the first and first estimations estimated by the inspection method are performed.
- the exposure conditions at the time of wafer exposure are corrected in accordance with the exposure conditions of No. 2 (step 162B).
- the exposure conditions by the exposure apparatus 100A are corrected according to the first and second exposure conditions estimated by the inspection apparatus 1A or the inspection method using the inspection apparatus 1A.
- the exposure condition in the exposure apparatus 100A can be set to a target state efficiently and with high accuracy.
- the exposure apparatus 100A shown in FIG. 16B includes an on-body inspection apparatus 1A, and the stage of the inspection apparatus 1A is also used as the wafer stage WST in this embodiment.
- the exposure apparatus 100A and the inspection apparatus 1A may be separate.
- the inspection apparatus 1 ⁇ / b> A includes a stage 5 ⁇ / b> A that holds the wafer 10.
- the stage 5A is rotatable about a normal line at the center of the upper surface of the stage 5A (a line parallel to the Z axis in FIG. 16A and passing through the center of the upper surface of the stage 5A), and is two-dimensional. It can move in the direction (the direction along the X axis and the Y axis orthogonal to each other). Further, the stage 5A is rotated and moved in a two-dimensional direction by the drive unit 48 provided in the inspection apparatus 1A.
- the wafer may be illuminated with circularly polarized light or elliptically polarized light other than circularly polarized light, as in the first embodiment described above.
- a light source that emits linearly polarized light or elliptically polarized light can also be used.
- diffracted light from the surface of the wafer 10 may be received by the light receiving system 30A, and the exposure conditions may be evaluated based on the calculated Stokes parameters.
- the control unit 80A controls the light receiving system 30A so that the light receiving system 30A receives diffracted light from the surface of the wafer 10 based on known diffraction conditions.
- the quarter wavelength plate 33A is disposed on the optical path of the light receiving system 30A, but is not limited to this arrangement.
- the quarter wavelength plate 33A may be disposed on the optical path of the illumination system 20A.
- the light from the light guide fiber 24A may be disposed on the optical path of the light that has passed through the polarizer 26A.
- the plurality of apparatus conditions in this embodiment include the rotation angle of the analyzer 32A (the direction of the transmission axis of the analyzer 32A), the rotation angle of the stage 5A (the direction of the wafer), and the like. Can be included.
- the templates TD1, TD2, and TF1 obtained using the conditionally adjusted wafer 10a on which the repeated pattern is formed by the exposure apparatus 100A are used in the condition setting in FIG. 17 of the present embodiment. Then, the exposure conditions (exposure amount and focus position) of the exposure apparatus 100A used for condition determination were obtained, but using the templates TD1, TD2, and TF1, the exposure conditions of the machine different from the exposure apparatus 100A were obtained. Also good.
- the Stokes parameters S1 and S2 may be used for the evaluation of the exposure amount
- the Stokes parameters S1 and S3 may be used for the evaluation of the focus position, respectively, as in the first embodiment described above.
- the determination of the exposure amount is at least selected from the Stokes parameters S1 (or S1, S2, S3).
- the focus position may be determined using the Stokes parameter S1 (or at least one parameter selected from S1 and S3).
- the change in the Stokes parameter with respect to the change in the exposure amount, and the focus position may be selected as appropriate so that the first device condition and the second device condition can be obtained based on the change in the Stokes parameter with respect to the change in.
- the angle of the quarter-wave plate 33A is set to at least four different angles. At least four wafer images may be taken.
- the template stored in the storage unit 85 in step 132A and step 134A in this embodiment is data in which the values of arbitrary Stokes parameters corresponding to arbitrary processing conditions are tabulated, but the template is limited to a table. It will never be.
- a curve obtained by mathematically fitting a change in an arbitrary Stokes parameter with respect to an arbitrary processing condition using an arbitrary function see, for example, FIGS. 13E and 13F) or an approximate expression may be used.
- the signal output unit 90A sends the exposure condition inspection result to a host computer (not shown) that comprehensively controls the operations of a plurality of exposure apparatuses and the like. It may be output.
- a host computer not shown
- information on the exposure amount error distribution (exposure amount unevenness) and focus position error distribution (defocus amount distribution) on the entire surface of the wafer 10 is sent from the signal output unit 90A to the host computer (Not shown).
- the host computer (not shown) issues an instruction for correcting the exposure condition (at least one of the exposure amount and the focus position) to the exposure apparatus 100A or a plurality of exposure apparatuses including the exposure apparatus 100A. May be issued.
- the template stored in the storage unit 85A in step 132B and step 134B of the present embodiment is, for example, an arbitrary Stokes parameter value for an arbitrary exposure condition using an arbitrary function.
- a curve or an approximate expression obtained by mathematical fitting may be used.
- curves BS21 and BS32 indicating changes in Stokes parameters S2 and S3 with respect to the exposure amount obtained under the first apparatus condition (here, apparatus conditions A and B) are represented as template TD1.
- TD2 or approximate expressions of the curves BS21, BS32 may be used as the templates TD1, TD2.
- the curve CS32 obtained under the second apparatus condition here, apparatus condition A
- the template TF1 the approximate expression of the curve CS32 may be used as the template TF1.
- step 158B and step 160B of the present embodiment for example, the measurement value Dx and measurement value Fy calculated in step 158B and step 160B and the measurement for the optimum exposure amount Dbe are performed.
- Various calculation methods such as the ratio of the value Dx and the ratio of the measured value Fy to the optimum focus position Zbe may be used. Further, the inspection results of these exposure conditions may not be displayed on a display device (not shown).
- the Stokes parameters S2 and S3 are calculated by a desired calculation formula so that the difference between the focus sensitivity and the dose sensitivity of the target Stokes parameter becomes larger. May be.
- Various arithmetic expressions can be used as the arithmetic expressions of the Stokes parameters S2 and S3.
- the arithmetic expressions such as “S2 + S3” (sum) and “S2 2 + S3 2 ” (square sum) may be used.
- the Stokes parameters S0 to S3 are calculated. Since the Stokes parameter S0 represents the total intensity of the light beam, only the Stokes parameters S1 to S3 are used to determine the exposure conditions. You may ask for it.
- the Stokes parameters S1, S2, and S3 of the reflected light change when the exposure amount changes, and when the focus position changes, the Stokes parameters S1 and S3 of the reflected light change relatively greatly, and the Stokes parameters change.
- the parameter S2 does not change much (see FIGS. 3A and 3B). For this reason, since it is possible to determine the conditions of the exposure amount and the focus position independently from only the Stokes parameters S2 and S3, it is only necessary to obtain the Stokes parameters S2 and S3.
- Stokes parameters of pixels corresponding to all shots SAn are calculated. Then, the calculation results may be averaged.
- the reason for calculating the shot average value is to suppress the influence of the aberration of the projection optical system PL of the exposure apparatus 100A.
- a value obtained by averaging the Stokes parameters of the corresponding pixels in the partial area CAn at the center of the shot SAn in FIG. 6B may be calculated.
- the exposure amount and the focus position are determined as the exposure conditions.
- the exposure conditions the exposure light wavelength, the illumination conditions (for example, the coherence factor ( ⁇ value), the projection optical system in the exposure apparatus 100A).
- the determination of the above embodiment may be used to determine the numerical aperture of PL or the temperature of the liquid during immersion exposure.
- the conditions that define the polarization state are represented by Stokes parameters.
- the conditions that define the state of polarization may be expressed by a Jones vector (Jones Vector) composed of two rows of complex column vectors for expressing the polarization characteristics of the optical system in the so-called Jones notation.
- the Jones notation is, for example, as described in Non-Patent Document 2, a Jones matrix (Jones Matrix) composed of a 2 ⁇ 2 complex matrix (polarization matrix) for representing the polarization characteristics of the optical system, It is described by the Jones vector for representing the polarization state converted by the optical system.
- a condition that defines the state of polarization may be expressed using both the Stokes parameter and the Jones vector. Furthermore, the conditions that define the state of polarization can be expressed by a so-called Mueller matrix.
- the exposure apparatuses 100 and 100A are scanning steppers using an immersion exposure method. However, the above-described embodiment is also applicable 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. 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.
- EUV light Extreme Ultraviolet Light
- a semiconductor device includes a design process (step 221) for designing the function and performance of the device, and a mask manufacturing process (mask) for manufacturing a mask (reticle) based on the design process (step 221).
- 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.
- a lithography process including a step of applying a resist to the wafer, an exposure step of exposing the reticle pattern onto the wafer by the exposure apparatuses 100 and 100A, and a developing step of developing the wafer, and an inspection apparatus
- An inspection process for inspecting the exposure conditions and the like using the light from the wafer is executed by 1 and 1A.
- the exposure conditions and the like are inspected using the above-described inspection apparatuses 1 and 1A, and for example, by correcting the exposure conditions and the like based on the inspection results, Yield can be improved.
- the device manufacturing method of the present embodiment the method of manufacturing a semiconductor device has been particularly described.
- 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.
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Abstract
Description
また、従来のフォーカス位置の検査方法では、専用の評価用のパターンを露光する必要があり、実デバイス用のパターンを露光する場合の評価が困難であった。
前記装置条件で前記検査対象基板の表面から射出した光の前記偏光状態を規定する条件に基づいて、前記検査対象パターンの前記加工条件を判定する検査部と、
を備える検査装置が提供される。
また、第3の態様によれば、検査対象のパターンの加工条件を判定する検査方法において、既知の前記加工条件でパターンが形成された基板から射出した光の偏光の状態を規定する条件に基づく検査条件で、前記検査対象のパターンが形成された検査対象基板の表面に偏光光を照明することと、
前記検査条件で前記検査対象基板の表面から射出した光を受光し、該光の前記偏光の状態を規定する条件を検出することと、
検出した前記偏光の状態を規定する条件に基づいて、前記検査対象のパターンの前記加工条件を判定することと、を含む検査方法が提供される。
また、第5の態様によれば、基板の表面にパターンを設ける加工工程を有するデバイス製造方法であって、その加工工程で第4の態様の露光方法を用いるデバイス製造方法が提供される。
以下、本発明の好ましい第1の実施形態につき図1(a)~図11(b)を参照して説明する。図1(a)は本実施形態に係る検査装置1を示す。図1(a)において、検査装置1は、略円板形の半導体ウェハ(以下、単にウェハという。)10を支持するステージ5を備え、不図示の搬送系によって搬送されてくるウェハ10は、ステージ5の上面(載置面)に載置され、例えば真空吸着によって固定保持される。以下、傾斜していない状態のステージ5の上面に平行な面において、図1(a)の紙面に平行な方向にX軸を取り、図1(a)の紙面に垂直な方向にY軸を取り、X軸及びY軸を含む面に垂直な方向にZ軸を取って説明する。なお、後述の図1(b)、(c)では、ウェハ10等の表面に平行な面において、直交する2つの軸をX軸及びY軸として、これらのX軸及びY軸を含む面に垂直な軸をZ軸としている。図1(a)において、ステージ5は、ステージ5の上面の中心における法線CAを回転軸とする回転角度φ1を制御する第1駆動部(不図示)と、例えばステージ5の上面の中心を通り、図1(a)の紙面に垂直な(図1(a)のY軸と平行な)軸TA(チルト軸)を回転軸とする傾斜角であるチルト角φ2(ウェハ10の表面のチルト角)を制御する第2駆動部(不図示)とを介してベース部材(不図示)に支持されている。
画像処理部40では、求めた撮像装置35の画素毎のストークスパラメータの情報を検査部60に出力する。検査部60はその情報を用いてウェハ10の繰り返しパターン12を形成する際に使用された露光装置100における露光条件等を判定する。そのようにウェハ面の画像の画素毎のストークスパラメータを求めたときの、検査装置1におけるウェハ面に対する照明光ILIの入射角θ1(もしくは、ウェハ面からの射出光の射出角θ2)、照明光ILIの波長λ(λ1~λ3等)、検光子32の回転角度(すなわち、検光子32の透過軸の方位)、偏光子26の回転角度(すなわち、偏光子26の透過軸の方位)、ステージ5の回転角度(すなわち、ウェハ10の方位)等の組み合わせを一つの装置条件と呼ぶ。装置条件は検査条件と呼ぶこともできる。そのように偏光状態の変化に基づいた検査を行う場合、その装置条件は偏光条件と呼ぶこともできる。そして、複数の装置条件が上記の記憶部85に記憶された検査装置1のレシピ情報に含まれている。本実施形態では、その複数の装置条件からウェハに形成されたパターンの露光条件を判定するのに適した装置条件を選択する。なお、照明光ILIの波長λ、ウェハ面に対する照明光ILIの入射角θ1、及び偏光子26の回転角度が検査装置1の装置条件に含まれる照明条件の一例であり、ウェハ面からの射出光の射出角(すなわち、受光系30による受光角)及び検光子32の回転角度が検査装置1の装置条件に含まれる検出部の検出条件の一例であり、ステージ5の回転角度、及びステージ5のチルト角φ2(すなわち、ウェハ面のチルト角)が検査装置1の装置条件に含まれるステージの姿勢条件の一例である。
次に、実際のデバイス製造工程において露光装置100による露光によって繰り返しパターンが形成されたウェハに対して、検査装置1によって上記の条件出しで求められた2つの装置条件を用いてウェハ面からの反射光のストークスパラメータを計測することによって、露光装置100の露光条件中の露光量及びフォーカス位置を以下のように判定する。この図5のフローチャートに示す検査動作はドーズ及びフォーカスモニターと呼ぶこともできる。まず、図6(a)と同じショット配列を持ち、レジストを塗布した実際の製品(例えば、半導体デバイス)となるウェハ10を露光装置100に搬送し、露光装置100によって、ウェハ10の各ショットSAn(n=1~N)に実際の製品用のレチクル(不図示)のパターンを露光し、露光後のウェハ10を現像する。この際の露光条件は、全部のショットにおいて、露光量に関してはそのレチクルに応じて定められている適正な露光量であり、フォーカス位置に関しては適正なフォーカス位置である。
上述のように、本実施形態の検査装置1及び検査方法は、露光量及びフォーカス位置を含む複数の露光条件のもとでの露光によりウェハ10に設けられた凹凸の繰り返しパターン12の露光条件を判定する装置及び方法である。そして、検査装置1は、パターン12が表面に形成されたウェハ10を保持可能なステージ5と、ウェハ10の表面を直線偏光の照明光ILI(偏光光)で照明する照明系20と、ウェハ10の表面から射出した光を受光し、該光のストークスパラメータS1~S3(偏光の状態を規定する条件)を検出する撮像装置35及び画像処理部40と、検査対象のウェハ10の表面に形成された検査対象のパターン12の露光条件を判定するための検査装置1の装置条件を、既知の露光条件でパターン12が形成された条件振りウェハ10aから射出した光のストークスパラメータに基づいて求める演算部50と、を備え、演算部50によって求められた装置条件でウェハ10の表面から射出した光のストークスパラメータに基づいて、パターン12の露光条件を判定している。
また、本実施形態の露光方法は、本実施形態の検査方法を用いてウェハの第1及び第2の露光条件を判定し(ステップ150~160)、その検査方法によって推定される第1及び第2の露光条件に応じてウェハの露光時の露光条件を補正している(ステップ162)。
また、上記の実施形態では、露光量及びフォーカス位置に対応して第1及び第2の装置条件を求めているが、例えばアンダードーズ及びオーバードーズに関して独立に感度の高い装置条件を求め、アンダーフォーカス及びオーバーフォーカスに関して独立に感度の高い装置条件を求めてもよい。
この場合、図5のステップ162において、ウェハ10の全面の露光量の誤差分布(露光量むら)及びフォーカス位置の誤差分布(デフォーカス量の分布)の情報は、信号出力部90からホストコンピュータ(不図示)に提供されてもよい。そして、ホストコンピュータ(不図示)は提供された情報に基づいて、露光装置100もしくは露光装置100を含む複数の露光装置へ露光条件(露光量とフォーカス位置の少なくとも一方)を補正するための指令を出してもよい。また、例えば、信号出力部90は、得られた露光条件の判定結果に基づいて、露光条件が適正ではない旨の警告を露光装置100やホストコンピュータに提供してもよい。
第2の実施形態につき図13(a)~図15を参照して説明する。本実施形態においては、不図示のデバイス製造システムの加工条件を判定するために図1(a)の検査装置1を使用する。また、本実施形態では、いわゆるスペーサ・ダブルパターニング法(又はサイドウォール・ダブルパターニング法)で微細なピッチの繰り返しパターンが形成されたウェハの加工条件を判定する。なお、本実施形態における、デバイス製造システムは、露光装置100、不図示の薄膜形成装置、及び不図示のエッチング装置を含む。
本実施形態において、ウェハ10dのパターン17Bからの反射光のストークスパラメータから加工条件を判定するときに使用する複数の装置条件を選択する動作(条件出し)では、デバイス製造システム(不図示)による繰り返しパターン17Bの加工条件として、図13(b)のスペーサ層18のエッチング量te及びスペーサ層18の堆積量ts(薄膜堆積量)を想定する。
作成された複数(ここでは25枚)の条件振りウェハは順次、図1(a)の検査装置1のステージ5上に搬送される。そして、複数の条件振りウェハのそれぞれにおいて、ステップ102A~130Aの動作が実行される。
次に、実際のデバイス製造工程において繰り返しパターン17Bが形成されたウェハ10dに対して、検査装置1によってストークスパラメータを計測して、加工条件中のスペーサ層の堆積量ts及びスペーサ層のエッチング量teを判定する。このため、図15のステップ150Aにおいて、製造されたウェハ10dは、不図示のアライメント機構を介して図1(a)の検査装置1のステージ5上にロードされる。そして、制御部80は記憶部85のレシピ情報から上記の条件出しで決定された第1及び第2の装置条件を読み出す。そして、装置条件をスペーサ層の堆積量の変化に対するストークスパラメータS2の感度が高い第1の装置条件(装置条件D)に設定し(ステップ152A)、1/4波長板33の回転角を初期値に設定する(ステップ110C)。そして、照明光ILIをウェハ面に照射し、撮像装置35がウェハ面の画像信号を画像処理部40に出力する(ステップ112C)。次にステップ114Cで1/4波長板33の角度が360°回転されたと判定されるまで、1/4波長板33を例えば360°/256だけ回転し(ステップ116C)、ウェハ10dの像を撮像する(ステップ112C)という動作を繰り返すことで、1/4波長板33の異なる回転角に対応して256枚のウェハ面の像が撮像される。
この実施形態によれば、実際に製品となるデバイス用の繰り返しパターン17Bが形成されたウェハ10dを用いて2つの装置条件のもとで反射光の偏光状態の検査を行うことによって、そのパターンの形成時に使用されたエッチング装置におけるエッチング量をスペーサの堆積量の影響を除去して高精度に判定できる。さらに、薄膜形成装置におけるスペーサの堆積量をエッチング量の影響を除去して高精度に判定又は推定できる。
第3の実施形態につき図16(a)~図18を参照して説明する。図16(a)、(b)において、図1(a)に対応する部分には同一の符号を付してその詳細な説明を省略する。図16(b)は本実施形態に係る露光装置100Aを示す。図16(b)において、露光装置100Aは、例えば米国特許出願公開第2007/242247号明細書に開示されているように、レチクルRを露光光で照明する照明系ILSと、レチクルRを保持して移動するレチクルステージRSTと、レチクルRのパターンをウェハ10の表面に露光する投影光学系PLと、ウェハ10を保持して移動するウェハステージWSTと、ステージRST,WSTの駆動機構(不図示)と、液浸露光のために投影光学系PLとウェハ10との間に液体を供給する局所液浸機構(不図示)と、装置全体の動作を制御する主制御装置CONTとを備えている。さらに、本実施形態の露光装置100Aは、ウェハ10のパターンからの反射光のストークスパラメータを計測してそのパターンの露光条件を判定するオンボディの検査装置1Aを備えている。
次に、実際のデバイス製造工程において露光装置100による露光によって繰り返しパターンが形成されたウェハに対して、検査装置1Aによって上記の条件出しで求められた2つの装置条件を用いてウェハ面からの反射光のストークスパラメータを計測することによって、露光装置100Aの露光条件中の露光量及びフォーカス位置を以下のように判定する。図18に示すように、まず、図6(a)と同じショット配列を持ち、レジストを塗布した実際の製品となるウェハ10を露光装置100Aに搬送し、露光装置100Aによって、ウェハ10の各ショットSAn(n=1~N)に実際の製品用のレチクル(不図示)のパターンを露光し、露光後のウェハ10を現像する。この際の露光条件は、全部のショットにおいて、露光量に関してはそのレチクルに応じて定められている最適な露光量であり、フォーカス位置に関しては最適なフォーカス位置である。
上述のように、本実施形態の検査装置1A及び検査方法は、露光量及びフォーカス位置を含む複数の露光条件のもとでの露光によりウェハ10に設けられた凹凸の繰り返しパターン12の露光条件を判定する装置及び方法である。そして、検査装置1Aは、パターン12が表面に形成されたウェハ10を保持可能なステージ5Aと、ウェハ10の表面を直線偏光の照明光ILI(偏光光)で照明する照明系20Aと、ウェハ10の表面から射出した光を受光し、該光のストークスパラメータS1~S3(偏光の状態を規定する条件)を検出する撮像素子47及び画像処理部40Aと、検査対象のウェハ10の表面に形成された検査対象のパターンの露光条件を判定するための検査装置1Aの装置条件を、既知の露光条件でパターンが形成された条件振りウェハ10aから射出した光のストークスパラメータに基づいて求める演算部50Aと、を備え、演算部50Aによって求められた装置条件でウェハ10の表面から射出した光のストークスパラメータに基づいて、そのパターンの露光条件を判定している。
また、本実施形態の露光方法は、本実施形態の検査方法を用いてウェハの第1及び第2の露光条件を判定し(ステップ150B~160B)、その検査方法によって推定される第1及び第2の露光条件に応じてウェハの露光時の露光条件を補正している(ステップ162B)。
また、上述の実施形態において、露光装置100,100Aは液浸露光法を用いるスキャニングステッパーとしたが、露光装置としてドライ型のスキャニングステッパー又はステッパー等の露光装置を使用する場合にも上述の実施形態を適用して同様の効果が得られる。さらに、露光装置として、露光光として波長が100nm以下のEUV光(Extreme Ultraviolet Light)を使用するEUV露光装置、又は露光ビームとして電子ビームを用いる電子ビーム露光装置を使用する場合にも上述の実施形態が適用できる。
なお、本実施形態のデバイス製造方法では、特に半導体デバイスの製造方法について説明したが、本実施形態のデバイス製造方法は、半導体材料を使用したデバイスの他、例えば液晶パネルや磁気ディスクなどの半導体材料以外の材料を使用したデバイスの製造にも適用することができる。
Claims (36)
- パターンの加工条件を判定する検査装置において、
パターンが表面に形成された基板を保持可能なステージと、
前記基板の表面を偏光光で照明する照明部と、
前記基板の表面から射出した光を受光し、該光の偏光の状態を規定する条件を検出する検出部と、
既知の前記加工条件でパターンが形成された基板から射出した光の前記偏光の状態を規定する条件に基づく、検査対象基板の表面に形成された検査対象パターンの前記加工条件を判定するための装置条件を記憶する記憶部と、
前記装置条件で前記検査対象基板の表面から射出した光の前記偏光状態を規定する条件に基づいて、前記検査対象パターンの前記加工条件を判定する検査部と、を備える検査装置。 - 前記偏光の状態を規定する条件は第1規定条件及び第2規定条件を含み、
前記装置条件は、前記第1規定条件に基づく第1装置条件と、前記第2規定条件に基づく第2装置条件を含む、請求項1に記載の検査装置。 - 前記加工条件は、第1加工条件と第2加工条件を含み、
前記検査部は、前記第1装置条件で前記検査対象基板の表面から射出した光の前記第1規定条件に基づいて、前記検査対象パターンの前記第1加工条件を判定し、前記第2装置条件で前記検査対象基板の表面から射出した光の前記第2規定条件に基づいて、前記検査対象パターンの前記第2加工条件を判定する、請求項2に記載の検査装置。 - 前記偏光の状態を規定する条件は第1規定条件及び第2規定条件を含み、
前記装置条件は、既知の前記加工条件でパターンが形成された基板から射出した光の前記第1規定条件と前記第2規定条件を用いた演算式で算出された結果に基づく条件であって、
前記検査部は、検出した前記第1規定条件と前記第2規定条件を用いて前記演算式で算出された結果に基づいて、前記検査対象パターンの前記加工条件を判定することを含む請求項1に記載の検査装置。 - 前記加工条件は第1加工条件及び第2加工条件を含み、
前記装置条件は、既知の前記第1加工条件及び既知の前記第2加工条件を組み合わせた加工条件でパターンが形成された基板から射出した光の前記偏光の状態を規定する条件の変化が、前記第1加工条件及び前記第2加工条件の変化に対して他方の加工条件が変化した場合より大きくなる条件である請求項1~4のいずれか一項に記載の検査装置。 - 前記検査部は、既知の前記加工条件でパターンが表面に形成された基板を偏光光で照明して、前記基板の表面から射出した光から検出した該光の偏光の状態を規定する条件に基づいて、前記検査条件を求める請求項1~4のいずれか一項に記載の検査装置。
- 前記検出部は、前記光の偏光の状態を規定する条件としてストークスパラメータ及びジョーンズベクトルの少なくとも一方を検出する請求項1~6のいずれか一項に記載の検査装置。
- 前記装置条件は、前記照明部の照明条件と、前記検出部の検出条件と、前記ステージの姿勢条件との少なくとも1つの条件を含む請求項1~7のいずれか一項に記載の検査装置。
- 前記照明条件は、前記基板の表面に入射する偏光光の入射角と、前記基板の表面に入射する偏光光の波長と、前記基板の表面に入射する偏光光の偏光方向との少なくとも1つの条件を含む請求項8に記載の検査装置。
- 前記検出条件は、前記検出部で受光する前記基板の表面から射出した光の受光角と、前記検出部で受光する前記基板の表面から射出した光の偏光方向との少なくとも1つの条件を含む請求項8に記載の検査装置。
- 前記姿勢条件は、前記ステージに保持された基板に形成されたパターンの繰り返し方向の方位と、前記ステージの傾斜角度との少なくとも1つの条件を含む請求項8に記載の検査装置。
- 前記照明部は、前記基板の表面に直線偏光光を照射する請求項1~11のいずれか一項に記載の検査装置。
- 前記検出部は、前記基板の表面から正反射した光を受光し、該光の前記偏光の状態を規定する条件を検出する請求項1~12のいずれか一項に記載の検査装置。
- 前記検査対象基板の表面に形成された前記検査対象のパターンは、露光装置による露光を含むリソグラフィ工程を経て形成され、
前記検査装置が判定する前記加工条件は、前記露光装置における露光の露光量及びフォーカス状態の少なくとも一方を含む請求項1~13のいずれか一項に記載の検査装置。 - 前記照明部は、前記基板の表面の全面を前記偏光光で一括して照明し、
前記検出部は、前記基板の表面の全面の像を撮像する撮像素子を有する請求項1~14のいずれか一項に記載の検査装置。 - 前記照明部は、前記基板の表面の一部を前記偏光光で照明し、
前記検出部は、前記基板の表面の一部の像を撮像する撮像素子を有し、
前記ステージは、前記照明部からの前記偏光光が前記基板の表面の全面に順次照射されるように、前記基板を移動可能である請求項1~14のいずれか一項に記載の検査装置。 - 前記検査部は、前記検査対象基板の表面に形成された検査対象のパターンの前記加工条件に起因する形状を判定するための該検査装置の装置条件を、既知の前記加工条件でパターンが形成された基板から射出した光の前記偏光の状態を規定する条件に基づいて求め、
前記装置条件で前記検査対象基板の表面から射出した光の前記偏光の状態を規定する条件に基づいて、前記検査対象パターンの前記加工条件に起因する形状を判定する請求項1~16のいずれか一項に記載の検査装置。 - 基板の表面にパターンを露光する投影光学系を有する露光部と、
請求項1~17のいずれか一項に記載の検査装置と、
前記検査装置によって判定された前記加工条件に応じて前記露光部における加工条件を補正する制御部と、を備える露光システム。 - 検査対象のパターンの加工条件を判定する検査方法において、
既知の前記加工条件でパターンが形成された基板から射出した光の偏光の状態を規定する条件に基づく検査条件で、前記検査対象のパターンが形成された検査対象基板の表面に偏光光を照明することと、
前記検査条件で前記検査対象基板の表面から射出した光を受光し、該光の前記偏光の状態を規定する条件を検出することと、
検出した前記偏光の状態を規定する条件に基づいて、前記検査対象のパターンの前記加工条件を判定することと、を含む検査方法。 - 前記偏光の状態を規定する条件は第1規定条件及び第2規定条件を含み、
前記検査条件は、前記第1規定条件に基づく第1検査条件と、前記第2規定条件に基づく第2検査条件を含む請求項19に記載の検査方法。 - 前記加工条件は、第1加工条件と第2加工条件を含み、
前記判定することは、前記第1検査条件で前記検査対象基板の表面から射出した光の前記第1規定条件に基づいて、前記検査対象のパターンの前記第1加工条件を判定し、前記第2検査条件で前記検査対象基板の表面から射出した光の前記第2規定条件に基づいて、前記検査対象のパターンの前記第2加工条件を判定する、請求項20に記載の検査方法。 - 前記偏光の状態を規定する条件は第1規定条件及び第2規定条件を含み、
前記検査条件は、既知の前記加工条件でパターンが形成された基板から射出した光の前記第1規定条件と前記第2規定条件を用いて演算式で算出された結果に基づく条件であって、
前記判定することは、検出した前記第1規定条件と前記第2規定条件を用いて前記演算式で算出された結果に基づいて、前記検査対象のパターンの前記加工条件を判定することを含む請求項19に記載の検査方法。 - 前記加工条件は、第1加工条件と第2加工条件を含み、
前記検査条件は、既知の前記第1加工条件及び既知の前記第2加工条件を組み合わせた加工条件でパターンが形成された基板から射出した光の前記偏光の状態を規定する条件の変化が、それぞれ前記第1加工条件及び前記第2加工条件の変化に対して他方の加工条件が変化した場合より大きくなる条件である請求項19~22のいずれか一項に記載の検査方法。 - 既知の前記加工条件でパターンが表面に形成された基板を偏光光で照明して、前記基板の表面から射出した光から検出した該光の偏光の状態を規定する条件に基づいて、前記検査条件を求めること、
を含む請求項19~23のいずれか一項に記載の検査方法。 - 前記光の偏光の状態を規定する条件を検出することは、前記光のストークスパラメータ、及びジョーンズベクトルの少なくとも一方を検出することを含む請求項19~24のいずれか一項に記載の検査方法。
- 前記検査条件は、前記基板の表面を前記偏光光で照明するときの照明条件と、前記光の偏光の状態を規定する条件を検出するときの検出条件と、前記偏光光で照明される基板の姿勢条件との少なくとも1つの条件を含む請求項19~25のいずれか一項に記載の検査方法。
- 前記照明条件は、前記基板の表面に入射する偏光光の入射角と、前記基板の表面に入射する偏光光の波長と、前記基板の表面に入射する偏光光の偏光方向との少なくとも1つの条件を含む請求項26に記載の検査方法。
- 前記検出条件は、前記基板の表面から射出した光を検出するときの該光の受光角と、前記基板の表面から射出した光を検出するときの該光の偏光方向との少なくとも1つの条件を含む請求項26に記載の検査方法。
- 前記姿勢条件は、前記偏光光で照明される基板に形成されたパターンの繰り返し方向の方位と、前記基板の傾斜角度との少なくとも1つの条件を含む請求項26に記載の検査方法。
- 前記基板の表面を偏光光で照明することは、前記基板の表面に直線偏光光を照射することである請求項19~29のいずれか一項に記載の検査方法。
- 前記光の偏光の状態を規定する条件を検出することは、前記基板の表面から正反射した光を受光し、該光の前記偏光の状態を規定する条件を検出することを含む請求項19~30のいずれか一項に記載の検査方法。
- 前記検査対象基板の表面に形成された前記検査対象のパターンは、露光装置による露光を含むリソグラフィ工程を経て形成され、
前記加工条件を判定するときの加工条件は、前記露光装置における露光量及びフォーカス状態の少なくとも一方を含む請求項19~31のいずれか一項に記載の検査方法。 - 前記パターンが表面に形成された前記基板の表面を前記偏光光で照明するときに、前記基板の表面の全面を照明し、
前記基板の表面から射出した光を受光するときに、前記基板の表面の全面の像を撮像する請求項19~32のいずれか一項に記載の検査方法。 - 前記パターンが表面に形成された前記基板の表面を前記偏光光で照明するときに、前記基板の表面の一部を照明し、
前記基板の表面から射出した光を受光するときに、前記基板の表面の一部の像を撮像し、
前記偏光光が前記基板の表面の全面に順次照射されるように、前記基板を移動することを含む請求項19~32のいずれか一項に記載の検査方法。 - 基板の表面にパターンを露光し、
請求項19~34のいずれか一項に記載の検査方法を用いて前記パターンの前記加工条件を判定し、
前記検査方法によって判定される前記加工条件に応じて前記基板の露光時の加工条件を補正する露光方法。 - 基板の表面にパターンを設けるリソグラフィ工程を有するデバイス製造方法であって、
前記リソグラフィ工程で請求項35に記載の露光方法を用いるデバイス製造方法。
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WO2016104342A1 (ja) * | 2014-12-26 | 2016-06-30 | 株式会社 日立ハイテクノロジーズ | 露光条件評価装置 |
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---|---|---|---|---|
JP6190168B2 (ja) * | 2013-06-04 | 2017-08-30 | キヤノン株式会社 | 合焦方法、合焦装置、露光方法、およびデバイス製造方法 |
US10732510B2 (en) * | 2015-09-30 | 2020-08-04 | Nikon Corporation | Exposure apparatus and exposure method, and flat panel display manufacturing method |
CN106925534B (zh) * | 2015-12-29 | 2019-03-12 | 合肥美亚光电技术股份有限公司 | 物料的检测装置及色选机 |
US11029253B2 (en) * | 2017-03-30 | 2021-06-08 | Applied Materials Israel Ltd. | Computerized method for configuring an inspection system, computer program product and an inspection system |
KR20230090854A (ko) * | 2021-12-15 | 2023-06-22 | 삼성전자주식회사 | 3차원 영상을 이용한 웨이퍼 검사 장치 및 이를 이용한 웨이퍼 검사 방법 |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010096596A (ja) * | 2008-10-15 | 2010-04-30 | Nikon Corp | 評価装置 |
WO2010052934A1 (ja) * | 2008-11-10 | 2010-05-14 | 株式会社ニコン | 評価装置および評価方法 |
JP2011099822A (ja) * | 2009-11-09 | 2011-05-19 | Nikon Corp | 表面検査方法および表面検査装置 |
JP2013108779A (ja) * | 2011-11-18 | 2013-06-06 | Nikon Corp | 表面検査装置、表面検査方法、および露光システム |
Family Cites Families (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101451963B (zh) * | 2006-08-01 | 2013-02-20 | 以色列商·应用材料以色列公司 | 用于缺陷检测的方法和系统 |
JP2009097988A (ja) * | 2007-10-17 | 2009-05-07 | Nikon Corp | 表面検査装置 |
JP2012018003A (ja) * | 2010-07-06 | 2012-01-26 | Nikon Corp | 表面検査方法および表面検査装置 |
-
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Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2010096596A (ja) * | 2008-10-15 | 2010-04-30 | Nikon Corp | 評価装置 |
WO2010052934A1 (ja) * | 2008-11-10 | 2010-05-14 | 株式会社ニコン | 評価装置および評価方法 |
JP2011099822A (ja) * | 2009-11-09 | 2011-05-19 | Nikon Corp | 表面検査方法および表面検査装置 |
JP2013108779A (ja) * | 2011-11-18 | 2013-06-06 | Nikon Corp | 表面検査装置、表面検査方法、および露光システム |
Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2016104342A1 (ja) * | 2014-12-26 | 2016-06-30 | 株式会社 日立ハイテクノロジーズ | 露光条件評価装置 |
KR20170088911A (ko) * | 2014-12-26 | 2017-08-02 | 가부시키가이샤 히다치 하이테크놀로지즈 | 노광 조건 평가 장치 |
KR101992550B1 (ko) * | 2014-12-26 | 2019-06-24 | 가부시키가이샤 히다치 하이테크놀로지즈 | 노광 조건 평가 장치 |
US10558127B2 (en) | 2014-12-26 | 2020-02-11 | Hitachi High-Technologies Corporation | Exposure condition evaluation device |
WO2021106244A1 (ja) * | 2019-11-27 | 2021-06-03 | シンクロア株式会社 | 光学ユニット |
JPWO2021106244A1 (ja) * | 2019-11-27 | 2021-12-02 | シンクロア株式会社 | 光学ユニット |
JP7152075B2 (ja) | 2019-11-27 | 2022-10-12 | シンクロア株式会社 | 光学ユニット |
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