WO2014051121A1 - Light-exposure method and device, and device production method - Google Patents

Abstract

A light-exposure method in which a wafer in a vacuum environment is exposed to light using exposure light comprising extreme ultraviolet (EUV) light is provided with: a step in which exposure light is used to subject a wafer to scanning light exposure via a projection optical system and one portion of a pattern of a reticle supported on a reticle stage; a step in which a pattern surface of the reticle is irradiated, at a position separated in the scanning direction from an exposure-light-irradiated area of the reticle, with an electron beam; and a step in which detection results of secondary electrons generated from the pattern surface are used to examine the pattern surface. As a result, the imprinting, on a material body, of foreign matter deposition on a mask can be inhibited in cases when exposure light such as EUV light is used.

Description

Exposure method and apparatus, and device manufacturing method

The present invention relates to an exposure technique for exposing an object through a projection system using an energy beam in a vacuum environment, and a device manufacturing technique using this exposure technique.

An exposure apparatus that uses extreme ultraviolet light (hereinafter referred to as EUV light) having a wavelength of about 100 nm or less as exposure light in a photolithography process for manufacturing various electronic devices (microdevices) such as semiconductor devices. , EUV exposure apparatus) is being used. Since EUV light is absorbed by a normal optical material and gas, the reticle as a mask and the main optical member provided in the EUV exposure apparatus are substantially reflecting members, and the exposure main body is accommodated in a vacuum chamber.

Further, in an exposure apparatus (light exposure machine) that uses exposure light having a conventional wavelength of about 193 nm or more, dust or the like adheres to the pattern surface of the reticle, and an image of the dust or the like is prevented from being transferred to an exposure target. Therefore, the pattern surface of the reticle during conveyance and exposure is covered with a thin protective film (so-called pellicle) stretched through a rectangular frame-shaped member. However, since EUV light is absorbed by the protective film, in the EUV exposure apparatus, no protective film is provided on the pattern surface of the reticle being conveyed and exposed. In the EUV exposure apparatus, the reticle is individually accommodated in the reticle cassette during the period in which it is transported between the reticle cassette and the exposure main body, and is taken out from the reticle cassette immediately before being loaded onto the exposure main body. (For example, refer to Patent Document 1).

International Publication No. 2006/051896 Pamphlet

In the EUV exposure apparatus, since no protective film is provided on the pattern surface of the reticle being exposed, for example, foreign matter is attached to the pattern surface of the reticle loaded on the reticle stage or is held on the reticle stage. If foreign matter adheres to the pattern surface of the reticle during exposure, the image of these foreign matter may be transferred to the exposure target.
In the present invention, in view of such circumstances, when an object is exposed through an optical member such as EUV light and exposure light that is easily absorbed by gas and the mask, the foreign matter attached to the pattern surface of the mask The object is to make it possible to suppress transfer to an object.

According to a first aspect of the present invention, in an exposure method of illuminating a pattern of a mask with an energy beam in a vacuum environment and exposing an object with the energy beam through the pattern and a projection system, the mask stage is used with the energy beam. The mask is moved by moving the mask stage in the scanning direction and the object is moved in the corresponding direction while exposing the object through a part of the mask pattern held on the projection surface and the projection system. Performed in synchronization, irradiating the pattern surface of the mask with the first electron beam from the first electron beam source at the first position, and irradiating the first electron beam from the pattern surface of the mask An exposure method including: detecting a first generated energy to be detected and inspecting the pattern surface of the mask using the detection result. It is.

According to the second aspect, in the exposure method of illuminating a mask pattern with an energy beam in a vacuum environment and exposing an object with the energy beam through the pattern and the projection system, the mask is arranged to be movable in the scanning direction. Holding the first mask and the second mask at positions separated in the scanning direction of the mask stage, and exposing the object with the energy beam through a part of the pattern of the second mask and the projection system The movement of the second mask by the movement of the mask stage in the scanning direction and the movement of the object in the corresponding direction are performed synchronously, and the mask stage is used to expose the object by the mask stage. When the second mask is moving in the scanning direction, the pattern surface of the first mask held on the mask stage at the first position First irradiation energy generated by irradiation of the first electron beam from the first electron beam source and irradiation of the first electron beam from the pattern surface of the first mask is detected, and the first generated energy is detected using the detection result. Performing an inspection of the pattern surface of one mask.

According to the third aspect, in the exposure apparatus that illuminates the pattern of the mask with the energy beam in a vacuum environment and exposes the object with the energy beam through the pattern and the projection system, the mask is held and the scanning direction A mask stage movably disposed on the mask stage, a part of the mask pattern held on the mask stage with the energy beam, and the scanning direction of the mask stage while exposing the object through the projection system A control unit that synchronizes the movement of the mask and the movement of the object in the corresponding direction by moving to the first position, and the first electrons that irradiate the pattern surface of the mask at the first position with the first electron beam. A beam detector and a first detector for detecting first generated energy generated by irradiation of the first electron beam from the pattern surface of the mask , An inspection unit for inspecting the pattern surface of the mask by using a detection result of the first detector, the exposure apparatus comprising a are provided.

According to the fourth aspect, in the exposure apparatus that illuminates the pattern of the mask with the energy beam in a vacuum environment and exposes the object with the energy beam through the pattern and the projection system, the first mask and the second mask Of the second mask held on the mask stage with the energy beam to expose the object, and a mask stage arranged to be movable in the scanning direction while being held away from the scanning direction. The movement of the second mask by the movement of the mask stage in the scanning direction and the movement of the object in the corresponding direction are performed in synchronism while exposing the object through a part of the projection system and the projection system. When the second mask is moved in the scanning direction by the mask stage in order to expose the object with the control unit, at the first position. A first electron beam source for irradiating a pattern surface of the first mask held on the mask stage with a first electron beam, and a first generation generated by irradiation of the first electron beam from the pattern surface of the first mask An exposure apparatus is provided that includes a first detection unit that detects energy, and an inspection unit that inspects the pattern surface of the first mask using a detection result of the first detection unit.

Further, according to the fifth aspect, the pattern of the photosensitive layer is formed on the substrate using the exposure method of the first or second aspect or the exposure apparatus of the third or fourth aspect, and the pattern is Processing the formed substrate. A device manufacturing method is provided.

According to the aspect of the present invention, when the energy beam is exposure light that is easily absorbed by an optical member and gas, such as EUV light, the pattern surface of the mask is exposed when the object is exposed through the energy beam and the mask. It is possible to suppress the transfer of foreign matter adhering to the object.

1 is a cross-sectional view showing a schematic configuration of an exposure apparatus according to a first embodiment of the present invention. (A) is an enlarged perspective view showing a foreign object detection device in FIG. 1, and (B) is an enlarged perspective view showing another configuration example of the detection device. (A) is a plan view showing a relative movement mechanism between the detection device and the reticle, and (B), (C), (D), and (E) show the detection region and the reticle from the state of FIG. It is a top view which shows the state which gradually moves relatively. It is a flowchart which shows the exposure method which concerns on 1st Embodiment. (A) is a diagram showing a detection device of a first modification, (B) is an enlarged cross-sectional view showing an electron optical system unit in FIG. 5 (A), and (C) is a relative view of the detection device in FIG. FIG. 4D is a plan view showing a relative movement trajectory of a detection point of the detection device. (A) is a plan view showing the arrangement of the two detection devices of the second modification, and (B) and (C) are relative movements of the first and second detection devices and the reticle of FIG. 6 (A), respectively. (D) is a diagram showing a region inspected by two detection devices in the pattern region of the reticle. (A) is a plan view showing a reticle stage system and a foreign matter detection apparatus according to the second embodiment, and (B) is a diagram showing a state in which a second reticle is inspected during exposure of the first reticle. (A) is a figure which shows the state which starts the exposure of a 2nd reticle in 2nd Embodiment, (B) is a figure which shows the state which test | inspects a 1st reticle. It is a flowchart which shows the exposure method which concerns on 2nd Embodiment. It is a flowchart which shows an example of the manufacturing process of an electronic device.

[First Embodiment]
A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a cross-sectional view schematically showing a configuration of a main part of the exposure apparatus EX according to the present embodiment. The exposure apparatus EX uses, as exposure light (exposure illumination light or exposure beam) EL, EUV exposure that uses EUV light (Extreme Ultraviolet Light) of, for example, 11 nm or 13 nm within a wavelength range of about 100 nm or less and about 3 to 50 nm. Device. In FIG. 1, an exposure apparatus EX includes a laser plasma light source 10 that generates a pulse of exposure light EL, and an illumination optical system ILS that illuminates an illumination area 27R on a pattern surface Ra (here, the lower surface) of a reticle R (mask) with the exposure light EL. A reticle stage RST that moves while holding the reticle R, and an image of a pattern in the illumination area 27R of the reticle R are projected onto the surface of a semiconductor wafer (hereinafter simply referred to as a wafer) W coated with a resist (photosensitive material). Projection optical system PO. Further, the exposure apparatus EX includes a detection device 52, which will be described later, capable of detecting the foreign matter on the pattern surface Ra by irradiating the electron beam EB1 to the pattern surface Ra, a foreign matter processing unit 36, which will be described later, that processes the detected foreign matter, and the wafer W. And a main control unit 31 including a computer for comprehensively controlling the operation of the entire apparatus.

In this embodiment, since EUV light is used as the exposure light EL, the illumination optical system ILS and the projection optical system PO are composed of reflective optical members such as a plurality of mirrors except for a specific filter or the like (not shown). The reticle R is also a reflection type. The reflective optical member is obtained by, for example, processing the surface of a member made of low thermal expansion glass (or quartz or high heat-resistant metal) into a predetermined curved surface or plane with high accuracy, and then, for example, molybdenum (Mo) on the surface. A reflective film is formed by forming a multilayer film (reflecting film of EUV light) with silicon (Si). The multilayer film may be another multilayer film in which a substance such as ruthenium (Ru) or rhodium (Rh) and a substance such as Si, beryllium (Be), or carbon tetraboride (B ₄ C) are combined. . The reticle R is formed, for example, by forming a multilayer film on the surface of a low-thermal-expansion glass substrate to form a reflective surface (reflective film), and then in a rectangular or square pattern area PA on the reflective surface, tantalum (Ta), nickel ( A transfer pattern is formed by an absorption layer made of a material that absorbs EUV light such as Ni) or chromium (Cr).

In order to prevent absorption of EUV light by gas, the exposure main body including the laser plasma light source 10, the reticle stage RST, the projection optical system PO, and the wafer stage WST of the exposure apparatus EX has a box-shaped vacuum chamber 1 as a whole. A large vacuum pump 32 for evacuating the space inside the vacuum chamber 1 is provided. Further, a sub chamber may be provided in the vacuum chamber 1 in order to further increase the degree of vacuum on the optical path of the exposure light EL. As an example, the pressure in the vacuum chamber 1 is about 10 ⁻⁵ Pa, and the pressure in the sub chamber (not shown) that accommodates the projection optical system PO in the vacuum chamber 1 is about 10 ⁻⁵ to 10 ⁻⁶ Pa. Since the inside of the vacuum chamber 1 is in such a high vacuum, the electron beam can reach the vacuum chamber 1 without a considerable distance being attenuated.

In addition, a robot chamber 2 provided with, for example, an articulated transfer robot 4 for delivering a reticle used for exposure is connected to the vacuum chamber 1 via a transfer port 1a opened and closed by a shutter 3, for example. ing. A reticle storage chamber (not shown) in which a reticle library for storing a plurality of reticles is installed is connected to the robot chamber 2 via a load lock chamber (not shown). The robot chamber 2 has a vacuum environment as in the vacuum chamber 1, the reticle storage chamber has an atmospheric pressure environment, and the load lock chamber switches between the atmospheric pressure environment and the vacuum environment. As an example, the reticle used for the exposure is accommodated and transported from the reticle library to the robot chamber 2 in a small airtight box-shaped reticle pod and taken out from the reticle pod in the robot chamber 2. The reticle is loaded onto the reticle stage RST in the vacuum chamber 1 by the transfer robot 4.

Hereinafter, in FIG. 1, the Z axis is taken in the normal direction of the surface (bottom surface of the vacuum chamber 1) on which the wafer stage WST is placed, and a plane perpendicular to the Z axis (in this embodiment, a plane substantially parallel to the horizontal plane). In the following description, the X axis is perpendicular to the paper surface of FIG. 1 and the Y axis is parallel to the paper surface of FIG. In the present embodiment, the illumination area 27R of the exposure light EL with respect to the reticle R has an arc shape elongated in the X direction (non-scanning direction) as shown in FIG. 3A, and the reticle R and the wafer during normal exposure. W is scanned in synchronism with the projection optical system PO in the Y direction (scanning direction).

First, the laser plasma light source 10 includes a high-power laser light source (not shown), a condensing lens 12 that condenses laser light supplied from the laser light source through the window member 15 of the vacuum chamber 1, and a tin ( This is a droplet target type light source including a nozzle 14 for ejecting a target droplet (Sn) or the like and a condensing mirror 13 having a spheroidal reflecting surface. For example, the exposure light EL pulse-emitted from the laser plasma light source 10 at a frequency of several kHz is condensed on the second focal point of the condenser mirror 13. The exposure light EL condensed at the second focal point becomes a substantially parallel light beam via a concave mirror (collimator optical system) 21, and a first fly-eye optical system 22 and a second fly-eye optical system 23 each composed of a plurality of mirrors. Reflected sequentially by the (optical integrator).

In FIG. 1, the illumination condition is set to normal illumination or a ring on a surface (a pupil plane of the illumination optical system ILS) where a surface light source is substantially formed in the vicinity of the reflection surface of the second fly's eye optical system 23 or a position in the vicinity thereof. A variable aperture stop (not shown) for switching to band illumination, dipole illumination, quadrupole illumination or the like is disposed. The exposure light EL reflected by the second fly's eye optical system 23 is averaged from below the arcuate illumination area 27R of the pattern surface Ra of the reticle R via a condenser optical system composed of a curved mirror 24 and a concave mirror 25. Illumination with a uniform illumination distribution at a small incident angle. The illumination optical system ILS includes the concave mirror 21, the fly-eye optical systems 22, 23, the curved mirror 24, and the concave mirror 25. The illumination optical system ILS is not limited to the configuration shown in FIG. 1, and various other configurations are possible.

In addition, in order to substantially define the shape of the illumination area 27R, a blind that shields the outer edge (−Y direction) of the exposure light EL incident on the illumination area 27R and the exposure light reflected by the illumination area 27R. A reticle blind (variable field stop) 26 is provided that includes a blind that blocks the outer edge of the EL (+ Y direction) and a pair of blinds (not shown) that define the position and width of the illumination area 27R in the X direction. It has been. The opening / closing operation of reticle blind 26 in the Y direction at the time of scanning exposure is controlled by stage control unit 33 under the control of main controller 31.

Next, the reticle R is sucked and held on the bottom surface (lower surface) of the reticle stage RST via an electrostatic chuck RH as a reticle holder, and the reticle stage RST is a reticle base RB disposed on the ceiling portion in the vacuum chamber 1. Are held at a predetermined gap along a guide surface (lower surface) parallel to the XY plane by a drive system composed of, for example, a magnetically levitated two-dimensional linear actuator. The pattern surface Ra of the reticle R is connected to a grounding part (not shown) of the reticle stage RST by a conduction mechanism 50, and this grounding part is outside the vacuum chamber 1 via a flexible signal line (not shown), for example. Is grounded. Since the pattern surface Ra of the reticle R is grounded in this way, charge accumulation on the pattern surface Ra is prevented even when the pattern surface Ra is irradiated with the electron beam EB1 as described later. When the pattern surface Ra is irradiated with the electron beam EB1, the pattern surface Ra can be regarded as an anode.

The position of the reticle stage RST in the X and Y directions, the tilt angle around the Z axis (θz direction), and the like are measured by a laser interferometer (not shown), and the reticle stage RST at a plurality of positions of the reticle stage RST (reticle R). The Z position is measured, for example, by an oblique incidence type autofocus sensor (not shown) that irradiates the pattern surface Ra obliquely through the opening of the reticle blind 26. The stage control unit 33 controls the above drive system based on the measurement values of the laser interferometer and autofocus sensor and the control information from the main control device 31 to place the reticle stage RST on the guide surface of the reticle base RB. Along with driving in a predetermined movable range along the Y direction, it is possible to drive within a certain range in the X direction and the θz direction. A partition (not shown) may be provided in the vacuum chamber 1 so as to cover the reticle stage RST. The defocus amount of the projected image accompanying the change in the Z position of the reticle R may be corrected by controlling the Z position of the wafer W on the wafer stage WST side, for example.

The exposure light EL reflected by the illumination area 27R of the reticle R is directed to the projection optical system PO that forms a reduced image of the pattern on the object surface (first surface) on the image surface (second surface). As an example, the projection optical system PO is configured by holding six mirrors M1 to M6 with a lens barrel (not shown), non-telecentric on the object plane (pattern surface Ra) side, and an image plane (the surface of the wafer W). ) Side is a substantially telecentric reflective optical system, and the projection magnification β is a reduction magnification such as 1/4. As described above, since the projection optical system PO is non-telecentric on the object plane side, the detection device 52 can be easily installed above the projection optical system PO (a portion facing the reticle stage RST) close to the illumination area 27R. It is. The exposure light EL reflected by the illumination area 27R of the reticle R passes through the projection optical system PO to an exposure area 27W (an area optically conjugate with the illumination area 27R) of one shot area (die) of the wafer W. A reduced image of a part of the pattern in the pattern area PA of the reticle R is formed.

In the projection optical system PO, the exposure light EL from the reticle R is reflected upward (+ Z direction) by the first mirror M1, subsequently reflected downward by the second mirror M2, and then the third mirror M3. And reflected downward by the fourth mirror M4. Next, the exposure light EL reflected upward by the fifth mirror M5 is reflected downward by the sixth mirror M6 to form a partial image of the pattern of the reticle R on the surface of the wafer W. As an example, the projection optical system PO is a coaxial optical system in which the optical axes of the mirrors M1 to M6 overlap with the optical axis AX in common, and an aperture stop (not shown) in the vicinity of the pupil plane near the reflection surface of the mirror M2 or in the vicinity thereof. ) Is arranged. Note that the projection optical system PO does not have to be a coaxial optical system, and its configuration is arbitrary.

The wafer W is attracted and held on the wafer stage WST via an electrostatic chuck (not shown). Wafer stage WST is arranged on a guide surface arranged along the XY plane. Wafer stage WST is driven by stage control unit 33 via a drive system (not shown) composed of, for example, a magnetically levitated two-dimensional linear actuator, based on the measurement value of a laser interferometer (not shown) and control information of main controller 31. Then, it is driven in a predetermined movable range in the X direction and the Y direction, and is driven in the θz direction or the like as necessary. Wafer stage WST is also provided with a Z leveling stage (not shown) for correcting the Z position and the like of wafer W as required.

The wafer stage WST that moves the wafer W is arranged inside the partition 7 so that the gas generated from the resist on the wafer W does not adversely affect the mirrors M1 to M6 of the projection optical system PL during exposure. An opening that allows the exposure light EL to pass therethrough is formed in the partition 7, and the space in the partition 7 is evacuated by another vacuum pump (not shown). Further, the exposure apparatus EX includes a reticle and wafer alignment system (not shown) for detecting the positions of the alignment marks on the reticle R and the wafer W, respectively.

As a basic operation at the time of wafer W exposure, one shot area of the wafer W is moved to the scanning start position by the movement (step movement) of the wafer stage WST in the X and Y directions. Then, the exposure light EL is irradiated from the illumination optical system ILS to the illumination area 27R, and the exposure area 27W of the shot area of the wafer W is exposed with an image of the pattern in the illumination area 27R of the reticle R by the projection optical system PO. The stage controller 33 drives the reticle stage RST and wafer stage WST synchronously, and moves the reticle R and wafer W synchronously with respect to the projection optical system PO in the Y direction at a speed ratio corresponding to the projection magnification. An image of the pattern of the reticle R is scanned and exposed on the shot area. Then, by repeating the step movement and the scanning exposure by the step-and-scan method, the image of the pattern in the pattern area PA of the reticle R is sequentially exposed to the plurality of shot areas of the wafer W.

Next, the foreign substance detection device 52 and the foreign substance processing unit 36 of this embodiment will be described in detail. When the exposure light EL is EUV light as in the present embodiment, the EUV light is also absorbed by a protective film (pellicle) provided to protect the reticle pattern surface in a conventional optical exposure machine. Therefore, in the present embodiment, a protective film that covers the pattern surface Ra of the reticle R is not provided. As a result, for example, there is a possibility that foreign matters such as fine dust adhere to the pattern surface Ra of the reticle R conveyed from the robot chamber 2 into the vacuum chamber 1. Further, in the process of exposing the pattern image of the reticle R to, for example, one lot of wafers, there is a possibility that minute foreign matters generated from, for example, the laser plasma light source 10 or the resist on the wafer adhere to the pattern surface Ra.

If there is a protective film on the pattern surface of the reticle with a predetermined interval, even if a minute foreign matter adheres to the protective film, the image is defocused on the surface (wafer surface) of the wafer W, which is a substantial problem. It will not be. However, the image of the foreign matter directly attached to the pattern area on the pattern surface is transferred to the wafer surface as it is. For this reason, if a foreign substance of a size that affects the transferred pattern adheres to the pattern area of the reticle where no protective film is provided, the foreign substance from the reticle is removed or the reticle is It is preferable to perform cleaning (not shown) or replace the reticle.

When the minimum line width of the circuit pattern exposed on the wafer W by the exposure apparatus EX of the present embodiment is set to 20 nm, for example, it is preferable to exclude foreign matters that become an image having a size up to, for example, about a fraction of the minimum line width. . As an example, if the projection magnification β of the projection optical system PO is 1/4 and the minimum width of the image of the foreign matter to be detected on the wafer surface is 1/4 of 20 nm, the foreign matter to be detected on the pattern surface Ra of the reticle R The minimum width dmin is 20 nm as follows.

dmin = 20 × (1/4) × (1 / β) = 20 (nm) (1)
In an ordinary optical microscope using, for example, visible light as detection light, the resolution is coarser than about 100 nm in terms of line width, and thus such an optical microscope cannot be used for detecting foreign matter on a reticle used in an EUV exposure apparatus. Therefore, in the present embodiment, in order to detect the foreign matter on the reticle R for the EUV exposure apparatus, the detection device 52 that uses the electron beam EB1 as the detection beam is used. The detection device 52 is located immediately below the region in the vacuum chamber 1 where the reticle R moves, for example, at a position away from the reticle blind 26 (illumination region 27R) in the scanning direction (Y direction), and as much as possible in the illumination region 27R. Is located at a position P1 close to. In the present embodiment, the position P1 is located in the + Y direction away from the illumination area 27R, but the detection device 52 is arranged at a position P2 that is substantially symmetrical to the illumination area 27R in the −Y direction. May be. In the following, a case where foreign matter is detected in the pattern area PA of the pattern surface Ra of the reticle R will be described. However, foreign matter detection can be performed in a region other than the pattern area PA in the same manner.
Up to this point, the case where foreign matter has adhered to the pattern surface of the reticle has been described, but another problem arises when foreign matter adheres to the back surface on the opposite side of the reticle pattern surface. When the reticle is held by the electrostatic chuck with foreign matter attached to the back surface of the reticle, the foreign matter is sandwiched between the reticle and the electrostatic chuck. Since the rigidity of the electrostatic chuck is higher than the rigidity of the reticle, the reticle is deformed by the sandwiched foreign matter, and the pattern surface of the reticle locally protrudes. Since the projection system of an EUV exposure apparatus using a reflective reticle is non-telecentric on the object side (reticle side), if the height of the pattern surface changes locally, a local shift of the pattern occurs on the image side. . In order to cope with this problem, the exposure apparatus EX of the present embodiment includes a detection device 252 and a foreign matter processing unit 236 for inspecting the back surface of the reticle and removing foreign matter.

As shown in FIG. 2A, the detection device 52 includes an electron gun 52a that generates an electron beam EB1, and converts the generated electron beam EB1 into a parallel beam to be measured (here, a pattern area PA of the reticle R). For example, a focusing system 52b that irradiates a rectangular detection region 53 elongated in the X direction, an imaging system 52c that focuses the secondary electrons SB1 generated from the detection region 53 to form a magnified image, and 2 that captures the magnified image. It has a two-dimensional image sensor 52d. Thus, the detection device 52 is a projection projection type electron microscope type foreign object detection device. The distribution of detection signals of secondary electrons generated in the detection region 53 can be measured from the detection signals of the image sensor 52d.

FIGS. 3A to 3E are plan views of the reticle R and the detection device 52 of FIG. 1 viewed from the reticle base RB side, respectively. Note that reticle stage RST, electrostatic chuck RH, and reticle R are represented by a two-dot chain line. As shown in FIG. 3A, a moving device 54 for moving the detection device 52 in the X direction (non-scanning direction) with respect to the reticle stage RST (reticle R) is provided. As an example, the moving device 54 includes a guide portion 54c parallel to the X axis, holding portions 54a and 54b that hold both ends of the guide portion 54c, and a slide portion that drives the detection device 52 in the X direction along the guide portion 54c. 54d. The slide portion 54d incorporates an encoder and a drive motor for measuring the position in the X direction with respect to the guide portion 54c, and the main control device 31 drives the drive motor based on the measured value of the encoder, whereby the detection device 52 is moved. It can move in the X direction. The reticle R is movable relative to the detection device 52 in the scanning direction SD (Y direction) by the reticle stage RST. By combining the movement of the detection device 52 in the X direction and the movement of the reticle stage RST in the Y direction, at least a part of the pattern area PA of the reticle R is detected by the detection device 52 during scanning exposure using the reticle R. The detection area 53 can be scanned.

1 is also supplied with information on the position in the X direction of the detection device 52 moved by the movement device 54. The calculation unit in the signal processing unit 34 uses secondary electron detection signals (imaging signals) supplied from the detection device 52, information on the coordinates of the reticle stage RST, and information on the position of the detection device 52 in the X direction. The distribution of secondary electron detection signals (secondary electron image) in the pattern area PA of the reticle R can be obtained. As an example, information on the distribution of detection signals of secondary electrons (hereinafter referred to as a reference pattern) generated from a pattern in the pattern area PA of the reticle R without foreign matter is stored in advance in a storage unit in the signal processing unit 34. Is remembered. The determination unit in the signal processing unit 34 compares the distribution of detection signals of secondary electrons in the pattern area PA of the reticle R with the reference pattern to determine the distribution and size of foreign matter in the pattern area PA. .

Instead of the detection device 52, a scanning electron microscope (SEM) type foreign material detection device 52A may be used as shown in FIG.
In FIG. 2B, a detection device 52A includes an electron gun 52Aa that generates an electron beam EB1, a focusing system 52Ab that focuses the generated electron beam EB1 on a test surface (pattern area PA), and a focused electron beam EB1. A scanning system 52Ac that scans two-dimensionally at high speed within a small detection area 53A of the test surface, such as a square, and a detection unit 52Ad that detects secondary electrons SB1 generated from the test surface by irradiation with the electron beam EB1. Have. By processing the detection signal of the detection unit 52d by a signal processing unit similar to the signal processing unit 34 of FIG. 1, the distribution of secondary electron detection signals (secondary electron image) generated in the detection region 53A can be detected. .

In FIG. 1, as an example, the foreign substance processing unit 36 is disposed at a position close to the detection device 52 in the + Y direction opposite to the illumination area 27R. For example, the foreign material processing unit 36 irradiates the foreign material on the pattern surface Ra of the reticle R detected by the detection device 52 with a pulse laser beam such as a YAG laser to remove the foreign material. A moving device (not shown) for moving the foreign substance processing unit 36 in the X direction is also provided, similar to the moving device 54 for the detecting device 52. The control unit 35 controlled by the main control device 31 drives the moving device to control the position of the foreign material processing unit 36 in the X direction and controls the laser irradiation of the foreign material processing unit 36. In addition, as the foreign material processing unit 36, for example, a device that removes foreign material using a micro tweezer mechanism that can be manufactured by, for example, MEMS (Microelectromechanical Systems) technology, or foreign material is removed by electrostatic adsorption. For example, a device that removes foreign matter by blowing gas or fine particles onto the reticle can be used.

Next, an example of an exposure method including the foreign matter detection operation of the reticle R by the exposure apparatus EX of the present embodiment will be described with reference to the flowchart of FIG. This operation is controlled by the main controller 31. First, in step 102 in FIG. 4, the reticle stage RST in a state in which no reticle is loaded is moved to the reticle loading position A2 (holding position) in front of the transport port 1a in the + Y direction within the movable range. In the present embodiment, the loading position A2 is also the reticle unloading position, but the position A2 and the unloading position may be different. The loading position A2 includes a position near a certain target position.

In parallel with this operation, the reticle R taken out from the reticle pod (not shown) in the robot chamber 2 is held at the position A1 at the upper end of the transfer robot 4. Then, the transfer robot 4 moves the reticle R directly below the electrostatic chuck RH of the reticle stage RST through the transfer port 1a, holds the reticle R by the electrostatic chuck RH, and grounds the pattern surface Ra of the reticle R by the conduction mechanism 50. To do. Then, the reticle stage RST is driven to move a part of the pattern area PA of the reticle R to the illumination area 27R, thereby aligning the reticle R. Thereafter, as shown in FIG. 3B, the reticle R is moved so that the pattern area PA of the reticle R comes to the exposure start position (first scan start position) in the + Y direction, for example, in the illumination area 27R. (Step 104). At this stage, the exposure light EL is not irradiated. The reticle blind 26 is closed in the Y direction.
Here, as an example, the detection device 252 installed at a position P3 in the middle of moving the reticle R from the robot chamber 2 to the electrostatic chuck RH using the transfer robot 4 is inspected for the presence of foreign matter on the back surface of the reticle R. . Similarly to the one shown in FIG. 3, the detection device 252 can move in a direction orthogonal to the reticle conveyance direction, and can inspect the entire back surface of the reticle R. If a foreign object is found, the foreign object processing unit 236 removes the foreign object. Thereafter, the portion where the foreign matter is attached may be inspected again to confirm that the foreign matter has been removed. If foreign matter that cannot be removed remains, main controller 31 makes an operator call as an example, and informs the operator of the size and position information of foreign matter from which reticle R has not been removed. The reticle with foreign matter is taken out and cleaned or replaced with another reticle. In FIG. 1, the detection device 252 and the foreign substance processing unit 236 are installed in the robot chamber 2, but one or both of them may be installed in the vacuum chamber 1. Further, since the size of the foreign matter allowed on the back surface of the reticle R is larger than the size of the foreign matter allowed on the surface (pattern surface) of the reticle R (for example, a diameter of 10 microns or less), an electron beam is applied to the detection device 252. In addition to the apparatus used, an apparatus that detects light scattering, an optical microscope apparatus, an apparatus that detects light interference, and the like can also be used.

Then, the unexposed wafer W coated with the first resist of one lot is loaded onto the wafer stage WST, and the wafer W is aligned (step 106). In parallel with this operation, the moving device 54 moves the position of the detection region 53 of the detection device 52 in the X direction to the position of the end portion of the pattern region PA in the + X direction. The width of the detection region 53 in the X direction (non-scanning direction) is defined as d. Then, irradiation of the electron beam EB1 from the detection device 52 to the detection region 53 is started, and detection of the secondary electrons SB1 generated from the pattern in the detection region 53 (capturing a secondary electron image of the detection region 53) is started. (Step 108). The detection signal (imaging signal) of the secondary electrons SB1 is sequentially stored in the storage device of the signal processing unit 34 together with information on the relative position between the detection area 53 and the pattern area PA. In such a state where the detection of the foreign matter is continued, the irradiation of the exposure light EL is started from the illumination optical system ILS (step 110), and the scanning direction (here, −−) indicated by the arrow A4 of the reticle stage RST (reticle R). The movement in the Y direction is started (step 112). At this time, the detection area 53 moves relative to the pattern area PA in the + Y direction indicated by the arrow A5 (see FIG. 3B).

Thereafter, reticle blind 26 is opened in the Y direction (step 114), and wafer stage WST is driven in a corresponding direction in synchronization with reticle stage RST, whereby a pattern image in pattern area PA of reticle R is imaged on wafer W. One shot area is scanned and exposed (step 116). Then, the reticle blind 26 is closed (step 118), and the reticle stage RST is stopped (step 120). Thereafter, it is determined whether or not the next shot area of the wafer W is to be exposed (step 122). When the next shot area is to be exposed, the process proceeds to step 124 with the foreign object detection being continued, and FIG. C), the moving device 54 moves the detection device 52 (detection region 53) in the −X direction by the width d of the detection region 53. At this time, step movement of the wafer W in the X direction and / or Y direction is performed on the wafer stage WST side.

Thereafter, the operation returns to step 112, and reticle stage RST (reticle R) starts to move in the + Y direction indicated by arrow A6. In steps 114 to 120, pattern area PA of reticle R is placed on the next shot area of wafer W. An image of the pattern is scanned and exposed. At this time, the detection area 53 moves relative to the pattern area PA in the −Y direction indicated by the arrow A7 (see FIG. 3C). Thereafter, every time the next shot area of the wafer W is exposed, the detection of the foreign matter is continued, and step 124 (movement of the detection area 53 in the X direction) and steps 112 to 120 (reticle R in the Y direction) are performed. (Movement) is repeated.

In this case, even when the reticle stage RST is temporarily stopped (at the turning point of the reciprocating movement) in order to reverse the scanning direction of the reticle stage RST, the foreign object detection by the detection device 52 is continued. However, as shown in FIG. 3C, even when the foreign substance detection by the detection device 52 is paused during the period in which the reticle stage RST is substantially paused and the detection area 53 is out of the pattern area PA. Good. When the exposure of the wafer W is completed in step 122, the process proceeds to step 126, where the irradiation of the exposure light EL from the illumination optical system ILS is stopped, and the electron beam EB1 from the detection device 52 to the detection region 53 is stopped. Is stopped and foreign object detection is stopped (step 128).

In the present embodiment, the position of the detection region 53 is shifted in the Y direction with respect to the illumination region 27R. For this reason, as shown by a relative locus 56A in FIG. 3D, at the time of the scanning exposure of the wafer W so far, a portion of the pattern area PA of the reticle R, for example, about 2/3 in the + Y direction (hereinafter, referred to as the following) The detection area 53 is relatively moved (scanned) in PA2. For example, when the entire area of the inspected area PA2 of the reticle R by the detection area 53 is not completed during the exposure of one wafer, the inspection area 53 has been inspected during the exposure of a plurality of wafers. The scanning of the entire area PA2 may be completed.

On the other hand, no matter how many wafers are exposed, the detection area 53 does not reach the remaining 1/3 of the pattern area PA of the reticle R (hereinafter referred to as an undetected area) PA1. Therefore, in this state, foreign object detection is not performed in the undetected area PA1. Therefore, the operations of Steps 132 to 146 are executed substantially in parallel with the subsequent operation of Step 130. That is, in step 130, the exposed wafer W is unloaded, and thereafter the operation proceeds to step 150.

On the other hand, in step 132, as shown in FIG. 3E, the reticle stage RST is driven in the + Y direction, the moving device 54 moves the detection device 52 in the + X direction, and the end of the undetected area PA1 of the reticle R is detected. The detection area 53 is set in the part. Then, irradiation of the electron beam EB1 from the detection device 52 to the detection region 53 is started, and detection of a detection signal (imaging signal) of the secondary electrons SB1 generated from the pattern in the detection region 53 is started. In this state, the reticle stage RST is moved in the Y direction so that the detection area 53 crosses the undetected area PA1 in the Y direction, and the detection device 52 is moved in the X direction by the width d, As shown by a typical locus 56B, the detection area 53 is relatively moved over the entire surface of the undetected area PA1. Thereafter, foreign object detection by the detection device 52 is stopped.

If the entire detection area PA1 cannot be scanned with the detection area 53 during the time from the wafer unloading to the next wafer loading, the time from the wafer unloading to the next wafer loading a plurality of times. The entire detection area PA1 may be scanned with the detection area 53. After the entire surface of the undetected area PA1 is scanned, the calculation unit in the signal processing unit 34 detects the secondary electron SB1 stored in the storage unit in the signal processing unit 34, the detection region 53, and the reticle R. The distribution of detection signals of secondary electrons on the entire surface of the pattern area PA (the undetected area PA1 and the inspected area PA2) is obtained using information on the relative position with respect to the pattern area PA.

Next, the determination unit in the signal processing unit 34 compares the distribution of the detection signals of the secondary electrons with the reference pattern stored in advance, and as an example, the difference between the distribution of the detection signal and the reference pattern is determined in advance. A size and a position of a portion larger than a predetermined noise level are obtained (step 134). Further, as an example, the determination unit regards a portion having a difference larger than the noise level as having a size equal to or larger than the minimum width dmin as a foreign matter, and if there is this foreign matter, the pattern area PA Identify the position within. When there is no foreign object, information indicating that there is no foreign object is supplied to the main controller 31, and when there is a foreign object, information on the size and position of the foreign object is supplied to the main controller 31 (step 136). ). As another method for determining whether or not there is a foreign object, the difference value is, for example, experimental among the distribution of the difference between the detection signal of the detected secondary electrons and the reference pattern stored in advance. A portion exceeding the reference value defined in the above may be regarded as a foreign object.

If no foreign matter is detected in the pattern area PA of the reticle R, the operation proceeds to step 150. On the other hand, if a foreign object is detected in the pattern area PA of the reticle R in step 136, the operation proceeds to step 138, and the main controller 31 provides information on the size and position of the foreign object supplied from the signal processing unit 34. Is stored in an internal storage device. In the present embodiment, the main controller 31 further causes the foreign matter processing unit 36 to process the foreign matter (step 140). That is, by driving the moving device (not shown) of the reticle stage RST and the foreign substance processing unit 36, a portion where the foreign substance in the pattern area PA of the reticle R is detected in the irradiation region of the pulse laser beam of the foreign substance processing unit 36. It moves, and the part is irradiated with pulsed laser light from the foreign substance processing unit 36. This foreign substance processing operation is executed for all detected foreign substances. After that, the position where the foreign matter removal processing is performed in the pattern area PA is sequentially moved to the detection area 53 of the detection device 52, and foreign matter is detected again (step 142). Then, it is determined whether or not the portion of the foreign matter determined to have foreign matter in step 136 has been removed (step 144). If the foreign matter has been removed, the process proceeds to step 150.

On the other hand, if the foreign matter has not been removed in step 144, the main controller 31 makes an operator call as an example, and informs the operator of the size and position information of the foreign matter from which the reticle R has not been removed. Thereafter, for example, the reticle R is returned to the reticle storage chamber (not shown) and the like, and the reticle R is cleaned. The reticle R after the cleaning is loaded onto the reticle stage RST, and foreign matter inspection and exposure after step 104 are performed. As another method, the reticle R determined to have foreign matter remaining is replaced with another reticle having the same pattern, and foreign matter inspection and exposure after step 104 are performed on the replaced reticle. May be.

In step 150, if the next wafer is to be exposed, the process proceeds to step 106, where the foreign substance detection of the reticle R and the wafer exposure are executed in parallel. Even when foreign matter is detected on the reticle R after the exposure of the next wafer is completed, foreign matter processing in steps 138 to 146 is performed.
According to this exposure method, in parallel with the exposure of the wafer and the replacement of the wafer, the detection device 52 is used to inspect (determine) whether there is a foreign substance in the pattern area PA of the reticle R. If there is a foreign matter, the foreign matter processing is performed. If the foreign matter has not been removed, the exposure using the reticle R is stopped, so that the foreign matter is applied to the pattern surface Ra of the reticle R during the exposure process. It is possible to prevent unnecessary patterns from being exposed to the subsequent wafers when the wafer adheres. Accordingly, it is possible to improve the yield of semiconductor devices and the like that are finally manufactured, and to reduce the ratio of performing the subsequent processes on wafers on which unnecessary patterns are exposed.

As described above, the exposure apparatus EX of the present embodiment is an exposure apparatus that exposes the wafer W through the pattern of the reticle R and the projection optical system PO with exposure light EL (energy beam) made of EUV light in a vacuum environment. The exposure apparatus EX holds the reticle R and is arranged so as to be movable in the scanning direction (Y direction), a part of the pattern of the reticle R held on the reticle stage RST by the exposure light EL, and A stage control unit 33 that performs the movement of the reticle R by the movement of the reticle stage RST in the scanning direction and the movement of the wafer W in a corresponding direction while exposing the wafer W via the projection optical system PO; The secondary gun SB1 (first generated energy) generated from the electron gun 52a that irradiates the electron beam EB1 to the pattern surface Ra of the reticle R and the pattern surface Ra at a position P1 that is separated from the illumination region 27R with respect to the reticle R in the scanning direction. ) And the presence or absence of foreign matter on the pattern surface Ra using the detection result of the detection device 52. / Or signal processing unit 34 for inspecting the distribution or the like of foreign matter (the inspecting section), and a.

In addition, the exposure method using the exposure apparatus EX is such that the wafer W is exposed through a part of the pattern of the reticle R held on the reticle stage RST by the exposure light EL and the projection optical system PO, and the scanning direction of the reticle stage RST ( Step 116 in which the movement of the reticle R by the movement in the Y direction) and the movement of the wafer W in the corresponding direction are performed synchronously, and the pattern of the reticle R at a position P1 away from the illumination area 27R in the scanning direction. A step 108 of irradiating the surface Ra with the electron beam EB1 from the detection device 52; and a step of detecting the secondary electrons SB1 generated from the pattern surface Ra and inspecting the presence or absence of foreign matter on the pattern surface Ra using this detection result. 134, 136.

According to the present embodiment, when the wafer W is exposed through the reticle R without a protective film using an optical member such as EUV light and the exposure light EL that is easily absorbed by gas, it can be transmitted in a vacuum environment. The foreign matter adhering to the pattern surface of the reticle R is detected by using the electron beam EB1 that has the same resolution as EUV light. Accordingly, when using a reticle R without a protective film, for example, when foreign matter is detected on the pattern surface of the reticle R during exposure, by removing the foreign matter, cleaning the reticle R, or replacing the reticle R, etc. It is possible to prevent unnecessary patterns from being exposed on the wafer exposed thereafter.

Further, in the present embodiment, when a foreign object is detected in the pattern area PA of the reticle R, the foreign object removal unit 36 performs the removal process of the foreign object. Therefore, when the foreign object is removed, the reticle R is removed. Can be used for exposure. When foreign matter is detected in the pattern area PA, the reticle R may be cleaned or replaced with another reticle without performing on-body foreign matter processing. In this case, it is not necessary to provide the foreign substance processing unit 36.

In the present embodiment, the secondary generated from the electron gun 52a that irradiates the pattern surface Ra of the reticle R with the electron beam EB1 and the pattern surface Ra at a position P1 that is away from the illumination region 27R with respect to the reticle R in the scanning direction. Electron SB1 (first generated energy) is detected. In addition, the position P1 may be set inside the illumination area 27R (including the boundary portion of the illumination area 27R). In this case, for example, foreign matter adhering to the pattern surface of the reticle during exposure can be detected.
In the present embodiment, for example, foreign matter inspection of the reticle R held on the reticle stage RST may be performed during the maintenance of the exposure apparatus.
In this embodiment, the foreign matter detection of the reticle R is always performed during the exposure of each wafer. For example, after the exposure of a predetermined plurality of wafers, the foreign matter detection of the reticle R is performed during the exposure of the next wafer. May be performed.

Further, in the present embodiment, since the undetected area PA1 remains in the pattern area PA of the reticle R during the scanning exposure of the wafer W, foreign matter detection in the undetected area PA1 is performed during the unloading (or replacement) of the wafer. Is going. Thereby, foreign matter detection can be performed on the entire surface of the pattern area PA. For example, if the distance in the Y direction between the illumination area 27R and the detection area 53 can be reduced and no undetected area PA1 remains during scanning exposure of the wafer W, step 132 (foreign matter in the undetected area PA1) Detection) can be omitted.

In the present embodiment, a plurality of detection devices 52 (or 52A) are arranged in the X direction (non-scanning direction), and foreign matter inspection of the reticle R is performed in parallel using the plurality of detection devices 52 (or 52A). You may make it perform. Thereby, the foreign substance inspection time can be shortened.
Next, a first modification of the above embodiment will be described with reference to FIGS. 5A, 5C, and 5D, portions corresponding to those in FIGS. 3A to 3E are denoted by the same reference numerals, and detailed description thereof is omitted.

FIG. 5A shows a detection device 52B that performs foreign object inspection on the pattern surface of the reticle R in this first modification, and a moving device 54A that moves the detection device 52B in the X direction (non-scanning direction) with respect to the reticle R. Indicates. In FIG. 5A, the detection device 52B has a flat substrate 59 and a plurality of detection units 58 fixed on the surface of the substrate 59 facing the pattern surface Ra of the reticle R at a period p1 in the X direction. . The plurality of detection units 58 are arranged so as to be able to cover substantially the entire X-direction width of the pattern area PA of the reticle R.

As shown in the enlarged view of FIG. 5B, the detection unit 58 includes an emitter 58b that generates an electron beam EB1, and a test surface (here, a reticle) that acts as an anode of the electron beam EB1 emitted from the emitter 58b. A plurality of stages of ring-shaped gate electrodes 58c focused on the detection points 58a in the R pattern area PA), and a ring-shaped detection electrode 58d for detecting the secondary electrons SB1 generated from the detection points 58a. In addition, a power supply unit 58e for applying a voltage to the gate electrodes 58c in a plurality of stages and an amplification unit 58f for amplifying the current of the detection electrode 58d for each detection unit 58 are provided, and the detection signal obtained by the amplification unit 58f is signal processed. Part (not shown). The height of the detection unit 58 can be made smaller than about 1 mm, for example, and the working distance (WD) from the detection unit 58 to the test surface can be made smaller than about 1 mm, for example. Such a detection device 52B having a configuration in which a plurality of small electron microscopes are arranged in parallel can be manufactured using, for example, the MEMS technology.

5A, the moving device 54A includes a guide portion 54Aa parallel to the X axis and a movable range 60A having a width p1 or more in the X direction along the guide portion 54Aa (FIG. 5C). The slide portion 54 </ b> Ab is driven inside. An encoder is incorporated in the slide portion 54Ab.
When detecting the foreign matter in the pattern area PA of the reticle R during exposure using the detection device 52B and the movement device 54A of this modification, as shown in FIG. The corresponding detection point 58a is irradiated with the electron beam EB1, and the secondary electron SB1 from the detection point 58a is detected. In this state, the reticle stage RST scans the reticle R with respect to the illumination area 27R in the −Y direction indicated by the arrow A4, and as shown in FIG. 5D, the moving device 54A has a width of about the detection point 58a. The operation of moving the detection device 52B in the X direction by Δp (a width considerably smaller than the arrangement pitch p1) and the operation of scanning the reticle R in the + Y direction indicated by the arrow A6 with respect to the illumination region 27R are repeated.

By this operation, as indicated by the relative movement trajectory 56C of the plurality of detection points 58a, an area (inspected area) of about 2/3 of the pattern area PA of the reticle R is efficiently detected by the plurality of detection points 58a. Can be scanned. In this case, when the amount of movement of the detection device 52B in the X direction reaches the arrangement pitch p1, the detection of foreign matter on the entire surface of the inspected region is completed. Further, for example, during the wafer exchange, the undetected area of the pattern area PA is scanned with the plurality of detection points 58a, and the detection signals obtained on the entire surface of the pattern area PA are processed, thereby generating secondary electrons generated from the pattern area PA. It is possible to obtain a distribution of detection signals and to perform a foreign substance inspection. Also in this modification, if the interval in the Y direction between the illumination area 27R and the detection point 58a is narrowed and no undetected area remains, the foreign substance inspection during wafer replacement can be omitted.

Next, in the above-described embodiment, the foreign object detection device 52 (or 52A, 52B) is arranged in the direction of one edge portion with respect to the illumination region 27R. On the other hand, as shown in the second modification of FIGS. 6A to 6D, the first detection device 52 is arranged at the first position P1 in the + Y direction with respect to the illumination area 27R, and illumination is performed. The second detection device 52C may be disposed at a second position P2 that is substantially symmetrical to the position P1 in the Y direction with respect to the region 27R. Similarly to the detection device 52, the detection device 52C irradiates the detection region 53C elongated in the X direction with the electron beam EB2, and captures an image of the secondary electron SB2 (second generated energy) generated from the detection region 53C. Is a foreign matter detection device. Detection signals of secondary electrons of the detection devices 52 and 52C are supplied to a signal processing device (not shown). Similarly to the moving device 54 that moves the detection device 52 in the X direction, a moving device 54C that moves the detection device 52C in the X direction is provided. Further, for example, the foreign substance processing unit 36 is arranged close to the detection device 52, but the foreign substance processing unit 36 may be arranged close to the detection device 52C.

In this modification, in order to detect foreign matter in the pattern area PA of the reticle R during exposure, the reticle R is scanned in the −Y direction indicated by the arrow A4 with respect to the illumination area 27R as shown in FIG. 6B. In the first half, the + Y direction portion of the pattern area PA is scanned with the detection area 53 of the first detection device 52. In the latter half of the scanning, the −Y-direction portion of the pattern area PA is scanned with the detection area 53C of the second detection device 52C, and the detection devices 52 and 52C are moved to the width of the detection region 53 by the moving devices 54 and 54C. Move in the -X direction by the minute.

Thereafter, as shown in FIG. 6C, in the first half of scanning the reticle R in the + Y direction indicated by the arrow A6 with respect to the illumination area 27R, the −Y direction portion of the pattern area PA is scanned in the detection area 53C. In the latter half of the scanning, the + Y direction portion of the pattern area PA is scanned with the detection area 53. By repeating such an operation, the inspected area PA2 of about 2/3 in the + Y direction of the pattern area PA of the reticle R becomes the detection area 53 as shown by a relative locus 56A in FIG. Scanned. In parallel with this, as shown by the relative trajectory 56D in the pattern area PA at the position P3, the inspected area PA3 of about 2/3 in the −Y direction of the pattern area PA is scanned in the detection area 53C. The A region including the two inspected regions PA2 and PA3 covers the entire surface of the pattern region PA. Therefore, by detecting the detection signals obtained from the two detection devices 52 and 52C during the scanning exposure, it is possible to efficiently detect the foreign matter on the entire surface of the pattern area PA of the reticle R.

Note that the detection devices 52A and 52B described above can also be used as the detection devices 52 and 52C.
In the above-described embodiment and its modifications, secondary electrons generated from the pattern surface of the reticle R are detected, but the detection target is arbitrary. For example, when an electron beam is irradiated onto the pattern surface of the reticle R, reflected electrons, scattered electrons, X-rays (for example, characteristic X-rays) generated from the pattern surface, fluorescence, etc. (including light in a wavelength region other than X-rays) ) And the presence / absence of a foreign substance, the composition and / or size of the foreign substance, etc. may be inspected from this detection signal.

Further, instead of the foreign substance detection device 52, etc., an energy dispersive X-ray spectrometry (EDS or EDX) is performed from an X-ray generated from the test surface by irradiating the test surface with an electron beam. It is also possible to use an inspection apparatus that inspects and analyzes the composition of particles on the surface to be detected.
Further, instead of using the foreign substance detection device 52, etc., the composition of the particles on the test surface is determined using wavelength dispersive X-ray spectrometry (WDS or WDX) from X-rays generated from the test surface. An inspection device for inspection / analysis may be used.

In the above embodiment, when a foreign object is detected on the reticle R in steps 134 and 136, the foreign object is processed in steps 140 to 146. As another method, when a foreign object is detected on the reticle R, the position (or further the size) of the foreign object in the pattern area PA is simply stored in the storage unit in the signal processing unit 34 in step 138. You may keep it. In this case, for example, after the exposure of one or a plurality of predetermined wafers, the foreign matter inspection of the reticle R is performed again, and when the foreign matter is detected again at the previously detected position, the exposure operation is stopped and the reticle is stopped. R may be cleaned or replaced.

[Second Embodiment]
A second embodiment will be described with reference to FIGS. This embodiment differs from the first embodiment in that a reticle stage in which two reticles are arranged in a so-called tandem is used. Hereinafter, in FIGS. 7A to 8B, portions corresponding to FIGS. 3A to 3E and FIG. 6A are denoted by the same or similar reference numerals, and detailed description thereof will be given. Simplify or omit.

FIG. 7A shows a reticle stage and a foreign matter detection device of an exposure apparatus EXA that uses the EUV light of this embodiment as exposure light. The exposure apparatus EXA includes a reticle base RBA that is elongated in the Y direction (scanning direction) and is disposed on the ceiling of a vacuum chamber (not shown) similar to the vacuum chamber 1 of FIG. FIGS. 7A to 8B are plan views of the reticle stage and the like viewed from the reticle base RBA side. Note that the reticle base RBA, the reticle stage, and the like are represented by two-dot chain lines.

7A, the exposure apparatus EXA is supported on the guide surface (lower surface) of the reticle base RBA at a predetermined interval by a magnetic levitation actuator, for example, and is about twice as large as the reticle stage RST in FIG. 1 in the Y direction. And a reticle stage RSTA that is approximately twice as long in the Y direction as the reticle stage RST. The reticle stage RSTA can be driven to a certain extent in the X direction and the θz direction with respect to the reticle base RBA. The first and second reticles RA and RB are adsorbed and held adjacent to the lower surface of the reticle stage RSTA in the Y direction via electrostatic chucks RHA and RHB, respectively. The reticle stage RSTA is provided with a conduction mechanism (not shown) for grounding the reticles RA and RB. As an example, the patterns (represented by symbols A and B) formed in the pattern areas PAA and PAB of the reticles RA and RB are different from each other.

The exposure apparatus EXA includes an illumination optical system (not shown) that illuminates the illumination area 27R with exposure light made of EUV light, as with the illumination optical system ILS in FIG. In the present embodiment, the X-direction center of the illumination area 27R and the X-direction centers of the reticles RA and RB held by the reticle stage RSTA are substantially the same.
The exposure apparatus EXA is disposed at positions P4 and P5 that are substantially symmetrical in the + Y direction and the −Y direction with respect to the illumination area 27R, and performs detection of foreign matter by irradiating the detection areas 53 and 53C on the test surface with an electron beam. The first and second detection devices 52 and 52C and the first and second moving devices 54D and 54E that move the detection devices 52 and 52C in the X direction are provided. The other configuration of the exposure apparatus EXA is the same as that of the exposure apparatus EX of the first embodiment in FIG. 1, and an image of the pattern in the illumination area 27R by the projection optical system PO (not shown) is displayed on the wafer stage WST (not shown). The wafer W (not shown) held by (1) is subjected to scanning exposure.

An example of an exposure method including the foreign matter detection operation of the reticles RA and RB by the exposure apparatus EXA of the present embodiment will be described with reference to the flowchart of FIG. As an example, a case will be described in which a reticle RA and RB pattern image is double exposed on a wafer. First, in step 160 of FIG. 9, the reticle stage RSTA is moved to a loading position (not shown) at the end in the + Y direction within a movable range in the Y direction, for example, and electrostatic chucks RHA and RHB are carried out by a transfer robot (not shown). The reticles RA and RB are loaded via. Thereafter, alignment of reticles RA and RB is performed. When double exposure is performed in the order of the reticle RA and RB patterns on each shot area of a wafer (not shown), the reticle stage RSTA is driven in the −Y direction as shown in FIG. The pattern area PAA of the first reticle RA is moved to the exposure start position on the −Y direction side with respect to the area 27R (step 162). In this state, the detection area 53 of the detection device 52 is located on the + Y direction side with respect to the pattern area PAB of the second reticle RB.

Thereafter, the wafer exposure operation using the reticle RA in steps 164 and 166 and the foreign matter detection operation for the reticle RB in steps 168 to 174 are performed in parallel. That is, in step 164, an unexposed wafer (not shown) coated with a resist is loaded on a wafer stage (not shown), and in step 166, exposure light is irradiated to the illumination area 27R, and the reticle stage RSTA is driven. Then, the reticle RA is alternately moved in the + Y direction shown in FIG. 7A and the −Y direction shown in FIG. 7B with respect to the illumination area 27R, so that the shot area to be exposed on the wafer passes through the wafer stage. By moving in synchronization with the corresponding directions, the pattern image of the reticle RA is scanned and exposed on each shot area of the wafer.

On the other hand, in step 168, each time the detection area 53 scans the pattern area PAB of the reticle RB once in the Y direction while irradiating the detection area 53 with the electron beam from the detection device 52 and detecting secondary electrons, the movement is performed. The operation of moving the detection device 52 in the X direction by the width of the detection region 53 in the X direction is repeated by the device 54D. As a result, as shown by the relative movement locus 56E in FIG. 7B, the entire surface of the pattern area PAB of the reticle RB is scanned by the detection area 53, and foreign matter detection is performed on the entire surface of the pattern area PAB. it can. In subsequent steps 170 and 172, the presence / absence of foreign matters in the pattern area PAB, the distribution of foreign matters, and the like are determined in the same manner as in steps 134 and 136 in FIG. If there is a foreign substance, in step 174, the same foreign substance processing (foreign substance removal, cleaning, replacement, etc.) as in steps 138 to 146 in FIG. 4 is performed.

If no foreign matter is detected in the pattern area PAB of the reticle RB, the operation proceeds to step 176, and as shown in FIG. 8A, the pattern area PAB of the reticle RB is illuminated by driving the reticle stage RSTA. It moves to the exposure start position before 27R. Then, in step 178, the illumination area 27R is irradiated with exposure light, the reticle stage RSTA is driven, and the reticle RB with respect to the illumination area 27R is shown in the + Y direction shown in FIG. 8A and in FIG. 8B. By moving alternately in the −Y direction and moving the shot area to be exposed on the wafer in synchronization with the corresponding direction via the wafer stage, a pattern image of the reticle RB is duplicated in each shot area of the wafer. Exposed. The exposed wafer is unloaded and proceeds to the next process such as development (step 180), and the operation proceeds to step 190.

Also, the operations of steps 182 to 188 are executed in parallel with steps 178 and 180. In step 178, each time the detection area 53C scans the pattern area PAA of the reticle RA once in the Y direction while irradiating the detection area 53C with an electron beam from the detection apparatus 52C and detecting secondary electrons, the movement apparatus 54E. The operation of moving the detection device 52C in the X direction by the width in the X direction of the detection region 53C is repeated. As a result, as shown by the relative movement locus 56F in FIG. 8B, the entire surface of the pattern area PAA of the reticle RA is scanned with the detection area 53C, and foreign matter detection is performed on the entire surface of the pattern area PAA. it can. In subsequent steps 184 to 188, as in steps 170 to 174, the presence / absence of foreign matter in the pattern area PAA, the distribution of foreign matter, and the like are determined. If there is a foreign matter, foreign matter processing is performed. If there is no foreign matter in the pattern area PAA of the reticle RA, the process proceeds to step 190, where the next wafer is exposed (the same operation as in steps 162 to 188).

According to the exposure method of this embodiment, in the exposure apparatus EXA that uses the reticle stage RSTA in which the reticles RA and RB are arranged in tandem, the pattern image of one reticle RA (or RB) is exposed on the wafer. The foreign matter inspection is performed on the pattern area of the other waiting reticle RB (or RA). Therefore, for example, when a foreign substance is detected in the pattern area PAB of the reticle RB, it is possible to prevent unnecessary patterns from being exposed on the wafer by removing the foreign substance, cleaning, or replacing the reticle RB. Further, for example, when foreign matter is detected in the pattern area PAA of the reticle RA during exposure using the reticle RB, unnecessary patterns on the subsequent wafer are removed by removing the foreign matter, cleaning, or replacing the reticle RA. Exposure can be prevented, and the yield of semiconductor devices and the like finally manufactured can be maintained high.

In the present embodiment, double exposure is performed on the wafer using the first and second reticles RA and RB. However, it is not always necessary to perform double exposure. For example, exposure may be performed on different layers of the wafer using reticles RA and RB.
Also in this embodiment, any detection device such as the detection device 52A in FIG. 2B or the detection device 52B in FIG. 5A can be used as the detection devices 52 and 52C.
Also in the present embodiment, the position where the foreign matter is detected on the pattern surface of the reticle R may be set in the illumination area 27R of the exposure light (EUV light). In this case, for example, foreign matter adhering to the pattern surface of the reticle during exposure can be detected.

The present invention can also be applied to an exposure apparatus using a so-called twin reticle stage.
Further, when an electronic device (microdevice) such as a semiconductor device is manufactured using the exposure apparatus EX, EXA or the exposure method of the above embodiment, the electronic device has a function / performance of the device as shown in FIG. Step 221 for performing design, Step 222 for manufacturing a mask (reticle) based on this design step, Step 223 for manufacturing a substrate (wafer) as a base material of the device, and a mask by the exposure apparatus or exposure method of the above-described embodiment. The process of exposing the pattern to the substrate, the process of developing the exposed substrate, the substrate processing step 224 including the heating (curing) and etching process of the developed substrate, the device assembly step (dicing process, bonding process, packaging process, etc.) As well as the inspection step 226. It is manufactured through the.

In other words, the device manufacturing method uses the exposure apparatus or the exposure method according to the above-described embodiment to expose a substrate (wafer W) through a mask pattern and to process the exposed substrate. Step (ie, developing the resist on the substrate and forming a mask layer corresponding to the mask pattern on the surface of the substrate, and processing the surface of the substrate via the mask layer (heating, etching, etc.) Processing step).

According to this device manufacturing method, it is possible to suppress the exposure of the image of the foreign substance on the reticle onto the wafer W, so that the pattern of the reticle can be exposed with high accuracy, and the yield of the manufactured electronic device can be improved.
Further, the present invention is not limited to the application to the manufacturing process of a semiconductor device. For example, a manufacturing process such as a liquid crystal display element and a plasma display, an imaging element (CMOS type, CCD, etc.), a micromachine, a MEMS ( (Microelectromechanical systems), thin film magnetic heads, and various devices (electronic devices) such as DNA chips can be widely applied.

In the above-described embodiment, X-rays (EUV light) generated by a laser plasma light source are used as exposure light. However, as exposure light, for example, an X-ray composed of a discharge plasma light source or synchrotron radiation (Synchrotron Radiation) is used. Lines can also be used.
In the above-described embodiment, the case where EUV light is used as exposure light and an all-reflection projection optical system including only six mirrors is used has been described as an example. For example, an exposure apparatus equipped with a projection optical system composed of only four mirrors, as well as a VUV light source having a wavelength of 100 to 160 nm, for example, an Ar ₂ laser (wavelength 126 nm) as a light source, and having four to eight mirrors or the like. The present invention can also be applied to an exposure apparatus equipped with a projection optical system.

The present invention can also be applied to a case where a foreign substance inspection of a mask is performed in a scanning exposure type electron beam exposure apparatus using a mask.
In addition, this invention is not limited to the above-mentioned embodiment, A various structure can be taken in the range which does not deviate from the summary of this invention.

EX, EXA ... exposure apparatus, ILS ... illumination optical system, RST, RSTA ... reticle stage, R, RA, RB ... reticle, PA, PAA, PAB ... pattern area, PO ... projection optical system, W ... wafer, 1 ... vacuum Chamber 10, laser plasma light source 27 R illuminating area 31 master control device 34 signal processing unit 36 foreign material processing unit 52, 52 A, 52 B foreign material detection device 54 54 A moving device

Claims (41)

1. In an exposure method of illuminating a pattern of a mask with an energy beam in a vacuum environment and exposing an object with the energy beam through the pattern and a projection system,
   While exposing the object through a part of the mask pattern held on the mask stage by the energy beam and the projection system, the movement of the mask corresponding to the movement of the mask stage in the scanning direction corresponds to the object. Synchronize the movement in the direction,
   Irradiating a pattern surface of the mask with a first electron beam from a first electron beam source at a first position;
   An exposure method comprising: detecting a first generated energy generated by irradiation of the first electron beam from a pattern surface of the mask; and inspecting the pattern surface of the mask using the detection result.
2. 2. The exposure method according to claim 1, wherein the first position is set inside an illumination area of the energy beam with respect to the mask.
3. 2. The exposure method according to claim 1, wherein the first position is located away from the illumination region of the energy beam with respect to the mask in the scanning direction.
4. 4. The exposure method according to claim 1, wherein the inspection of the pattern surface includes an inspection of a foreign matter adhering to the pattern surface.
5. 5. The exposure method according to claim 1, wherein the first electron beam is irradiated onto the pattern surface while the mask is held on the mask stage.
6. When the pattern area of the mask passes through the illumination area in the scanning direction, the mask stage moves in the opposite direction; and
   Moving the first electron beam source in a direction intersecting the scanning direction by the width of the irradiation region of the first electron beam;
   The exposure method according to any one of claims 1 to 5, comprising:
7. Irradiating a pattern surface of the first mask with a second electron beam from a second electron beam source at a second position different from the first position in the scanning direction with respect to the illumination region;
   Detecting second generated energy generated by irradiation of the second electron beam from the pattern surface, and inspecting the pattern surface of the mask using the detection result;
   The exposure method according to any one of claims 1 to 6, comprising:
8. The projection system is non-telecentric on the object plane side;
   The exposure method according to claim 7, wherein the first position or the second position is located above the projection system.
9. When there is a remaining area in the pattern area of the mask that is not irradiated with the first electron beam within a period in which the mask is moved in the scanning direction by the mask stage to expose the object,
   During the exchange of the object, the mask stage is moved in the scanning direction toward the first position, and the remaining area of the mask is irradiated with the first electron beam to inspect the remaining area. The exposure method according to any one of claims 1 to 8, comprising:
10. 10. The exposure method according to claim 1, further comprising removing the foreign matter when the foreign matter is detected by inspection of the pattern surface of the mask.
11. Irradiating the back surface of the pattern surface of the mask with an electron beam;
    Detecting the generated energy generated by irradiation of the electron beam from the back surface of the mask, and inspecting the back surface of the mask using the detection result;
    The exposure method according to any one of claims 1 to 10, comprising:
12. 12. The exposure method according to claim 11, wherein the inspection of the back surface of the mask is performed before the mask is placed on the mask stage.
13. In an exposure method of illuminating a pattern of a mask with an energy beam in a vacuum environment and exposing an object with the energy beam through the pattern and a projection system,
    A first mask and a second mask are held at positions separated in the scanning direction of a mask stage arranged to be movable in the scanning direction, and the energy beam passes through a part of the pattern of the second mask and the projection system. Performing the movement of the second mask by the movement of the mask stage in the scanning direction and the movement of the object in a corresponding direction while exposing the object
    In order to expose the object, when the second mask is moved in the scanning direction by the mask stage, a first position is applied to a pattern surface of the first mask held on the mask stage. Irradiating a first electron beam from one electron beam source;
    Detecting a first generated energy generated by irradiation of the first electron beam from a pattern surface of the first mask, and inspecting the pattern surface of the first mask using the detection result;
    An exposure method comprising:
14. 14. The exposure method according to claim 13, wherein the first position is set inside an illumination area of the energy beam with respect to the mask.
15. 14. The exposure method according to claim 13, wherein the first position is located away from the illumination region of the energy beam with respect to the mask in the scanning direction.
16. When the pattern area of the second mask passes through the illumination area in the scanning direction and the direction of movement of the mask stage is reversed in the reverse direction,
    The exposure method according to any one of claims 13 to 15, further comprising: moving the first electron beam source in a direction intersecting the scanning direction by a width of an irradiation region of the first electron beam.
17. While the object is exposed to the energy beam through a part of the pattern of the first mask and the projection system, the movement of the first mask by the movement of the mask stage in the scanning direction corresponds to the object. Synchronize the movement in the direction,
    In order to expose the object, when the first mask is moved in the scanning direction by the mask stage, a second position that is substantially symmetric with respect to the first position in the scanning direction with respect to the illumination area. Irradiating a pattern surface of the second mask held on the mask stage with a second electron beam from a second electron beam source;
    Detecting second generated energy generated by irradiation of the second electron beam from the pattern surface of the second mask, and inspecting the pattern surface of the second mask using the detection result;
    The exposure method according to any one of claims 13 to 16, further comprising:
18. The exposure method according to any one of claims 13 to 17, further comprising removing the foreign matter when the foreign matter is detected by inspection of the pattern surface of the first mask.
19. The exposure method according to any one of claims 1 to 18, wherein the energy beam is EUV light.
20. The exposure method according to any one of claims 1 to 19, wherein the first generated energy includes at least one of an electron beam and an X-ray.
21. In an exposure apparatus that illuminates a pattern of a mask with an energy beam in a vacuum environment and exposes an object with the energy beam through the pattern and a projection system,
    A mask stage arranged to be movable in the scanning direction while holding the mask;
    Movement of the mask and the object by moving the mask stage in the scanning direction while exposing the object through a part of the pattern of the mask held on the mask stage by the energy beam and the projection system A control unit that synchronizes movement in the corresponding direction of
    A first electron beam source that irradiates a pattern surface of the mask with a first electron beam at a first position;
    A first detector for detecting first generated energy generated by irradiation of the first electron beam from the pattern surface of the mask;
    An inspection unit that inspects the pattern surface of the mask using a detection result of the first detection unit;
    An exposure apparatus comprising:
22. The exposure apparatus according to claim 21, wherein the first position is set inside an illumination area of the energy beam with respect to the mask.
23. The exposure apparatus according to claim 21, wherein the first position is located in a position away from the illumination region of the energy beam with respect to the mask in the scanning direction.
24. The exposure apparatus according to any one of claims 21 to 23, wherein the inspection unit inspects foreign matter adhering to the pattern surface of the mask.
25. The exposure apparatus according to any one of claims 21 to 24, wherein the first electron beam source irradiates the pattern surface with the first electron beam in a state where the mask is held on the mask stage.
26. When the pattern area of the mask passes through the illumination area in the scanning direction and the control unit turns the moving direction of the mask stage in the reverse direction, the first electron beam source is moved to the first electron beam. The exposure apparatus according to any one of claims 21 to 25, further comprising a moving device that moves in a direction intersecting the scanning direction by a width of an irradiation region.
27. A second electron beam source that irradiates a pattern surface of the mask with a second electron beam at a second position that is substantially symmetrical to the first position in the scanning direction with respect to the illumination region;
    A second detector for detecting second generated energy generated by irradiation of the second electron beam from the pattern surface,
    The exposure apparatus according to any one of claims 21 to 26, wherein the inspection unit inspects the pattern surface of the mask using detection results of the first detection unit and the second detection unit.
28. The projection system is non-telecentric on the object plane side;
    28. The exposure apparatus according to claim 27, wherein the first position or the second position is located above the projection system.
29. The exposure apparatus according to any one of claims 21 to 28, further comprising a foreign matter processing device that removes the foreign matter when the foreign matter is detected by inspection of the pattern surface of the mask.
30. An electron beam source for the back surface that irradiates the back surface of the pattern surface of the mask with an electron beam;
    A back surface inspection unit that detects energy generated by irradiation of the electron beam from the back surface of the mask, and inspects the back surface of the mask using the detection result;
    The exposure apparatus according to any one of claims 21 to 29, comprising:
31. 31. The exposure apparatus according to claim 30, wherein the back surface inspection of the mask by the back surface electron beam source and the back surface inspection unit is performed before the mask is placed on the mask stage.
32. In an exposure apparatus that illuminates a pattern of a mask with an energy beam in a vacuum environment and exposes an object with the energy beam through the pattern and a projection system,
    A mask stage arranged to be movable in the scanning direction while holding the first mask and the second mask at positions separated in the scanning direction;
    In order to expose the object, a part of the pattern of the second mask held on the mask stage by the energy beam and the object are exposed through the projection system, and in the scanning direction of the mask stage. A control unit that synchronizes the movement of the second mask and the movement of the object in a corresponding direction by movement of
    In order to expose the object, when the second mask is moved in the scanning direction by the mask stage, the first mask is held on the pattern surface of the first mask held on the mask stage at the first position. A first electron beam source that emits one electron beam;
    A first detector for detecting a first generated energy generated by irradiation of the first electron beam from a pattern surface of the first mask;
    An inspection unit that inspects the pattern surface of the first mask using a detection result of the first detection unit;
    Exposure apparatus.
33. The exposure apparatus according to claim 32, wherein the first position is set inside an illumination area of the energy beam with respect to the mask.
34. 33. The exposure apparatus according to claim 32, wherein the first position is located away from the illumination region of the energy beam with respect to the mask in the scanning direction.
35. When the pattern area of the second mask passes through the illumination area in the scanning direction and the controller turns the moving direction of the mask stage in the reverse direction, the first electron beam source is moved to the first electron. The exposure apparatus according to any one of claims 32 to 34, further comprising a moving device that moves in a direction intersecting the scanning direction by a width of a beam irradiation region.
36. A second electron beam source that irradiates a pattern surface of the second mask with a second electron beam at a second position that is substantially symmetrical to the first position in the scanning direction with respect to the illumination region;
    A second detection unit for detecting second generated energy generated by irradiation of the second electron beam from the pattern surface of the second mask,
    The exposure apparatus according to any one of claims 32 to 35, wherein the inspection unit inspects the pattern surface of the second mask using a detection result of the second detection unit.
37. The exposure apparatus according to any one of claims 32 to 36, further comprising a foreign matter processing device that removes the foreign matter when the foreign matter is detected by inspection of the pattern surface of the first mask.
38. The exposure apparatus according to any one of claims 21 to 37, wherein the energy beam is EUV light.
39. The exposure apparatus according to any one of claims 21 to 38, wherein the first generated energy includes at least one of an electron beam and an X-ray.
40. Forming a pattern of a photosensitive layer on a substrate using the exposure method according to any one of claims 1 to 20,
    Processing the substrate on which the pattern is formed;
    A device manufacturing method including:
41. Forming a pattern of a photosensitive layer on a substrate using the exposure apparatus according to any one of claims 21 to 39;
    Processing the substrate on which the pattern is formed;
    A device manufacturing method including:

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