JP2005079470A - Adjustment method of illumination optical system, method and device for exposure, device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an adjustment method or the like of an illumination optical system which reduces failure of telecentricity of the illumination optical system. <P>SOLUTION: The illumination optical system IS comprises a light source 1. Movable mirrors 2, 6, 9 which deflect incident light flux are arranged on an optical path between the light source 1 and a second fly eye lens 10. A second zoom optical system 8 is arranged between the first fly eye lens 7 and the second fly eye lens 10. Failure of illumination telecentricity of light flux directed to an irradiated surface LP or an incidence surface PL3 of the second fly eye lens 10 which is optically conjugate with the irradiated surface LP is corrected by adjusting the angle of movable mirrors 2, 6, 9 and at least one of positions of a lens 8a contained in the second zoom optical system 8 in a direction crossing an optical axis AX2. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an adjustment method of an illumination optical system that guides a light beam supplied from a light source to an irradiated surface, an exposure apparatus and method that uses an illumination optical system adjusted using the adjustment method, and a device that uses the exposure apparatus The present invention relates to a device manufacturing method for manufacturing a device.

  In a photolithography process that is usually provided as one of the manufacturing processes of a device such as a semiconductor element, a liquid crystal display element, an imaging device (CCD, etc.), a thin film magnetic head, etc., a substrate as an exposure target (a semiconductor wafer coated with a photoresist or An exposure apparatus for projecting and exposing a reduced image of a pattern formed on a mask or reticle (hereinafter collectively referred to as a mask) on a glass plate is used. In recent years, step-and-repeat reduction projection exposure apparatuses (so-called steppers) or step-and-scan exposure apparatuses are frequently used.

  In the above stepper, the substrate is placed on a substrate stage that is movable in two dimensions, and the substrate is stepped (stepped) by this substrate stage, and a reduced image of the mask pattern is applied to each shot area on the substrate. An exposure apparatus that sequentially repeats the batch exposure operation. In addition, a step-and-scan exposure apparatus uses a mask stage on which a mask is placed and a substrate stage on which a substrate is placed as a projection optical system in a state in which the mask is irradiated with slit-shaped pulse exposure light. In contrast, a part of the pattern formed on the mask is sequentially transferred to the shot area of the substrate while being synchronously scanned with each other. When the pattern transfer to one shot area is completed, the substrate is stepped to transfer the pattern to the other shot area. It is the exposure apparatus which performs.

  In order to faithfully transfer a fine pattern formed on a mask using these exposure apparatuses onto a substrate, it is necessary to eliminate unevenness in the amount of exposure light irradiated onto the substrate as much as possible. In order to eliminate this unevenness in the amount of light, it is necessary to make the illuminance distribution of the exposure light illuminated on the mask uniform. For this reason, an optical integrator such as a fly-eye lens or a rod lens that makes the illuminance distribution of the light beam supplied from the light source uniform is usually provided in the illumination optical system provided in the exposure apparatus.

In addition, if there is a collapse of telecentricity of the exposure light irradiated to the mask from the illumination optical system (that is, collapse of the illumination telecentricity), the principal ray of the exposure light is inclined with respect to the normal line of the mask and the normal line of the substrate. Therefore, the exposure light is incident on the mask and the substrate with an inclination. When exposure light is incident on the substrate in such a state, unevenness in the amount of light occurs, or a positional shift (shift) of the pattern image projected on the substrate occurs. Conventionally, the collapse of the illumination telecentric is corrected by moving an optical element such as a lens provided on the optical path between the optical integrator and the mask in the direction of the optical axis or by tilting the optical element. It was. For details of the correction method for correcting the collapse of the illumination telecentric, see, for example, Patent Documents 1 and 2 below.
JP 2001-313250 A JP 2002-015987 A

  By the way, when the illumination telecentrics are broken, as described above, unevenness in the amount of light on the substrate or displacement of the pattern image projected on the substrate occurs. With the recent miniaturization of patterns, the permissible unevenness of the amount of light on the substrate has become severe, and along with this, the collapse of the illumination telecentric allowed for the illumination optical system has also become smaller. For this reason, even if it corrected using the conventional correction method, the problem that collapse of illumination telecentric cannot be fully corrected has arisen.

  Further, in recent years, illumination conditions may be greatly changed as compared with the prior art in order to improve resolution as the pattern becomes finer. Here, the change of the illumination condition is, for example, the change of illumination NA (Numerical Aperture) and illumination shape by changing the distribution of exposure light in a plane conjugate with the pupil plane of the projection optical system in the illumination system. It is done. The illumination NA may be changed to a small σ that illuminates the mask substantially vertically to improve the resolution of the isolated pattern, for example. Also, the illumination shape may be changed to an annular illumination shape (annular illumination) for shielding zero-order light or a plurality (for example, four poles) of eccentric illumination shapes (deformed illumination). When the illumination condition is changed, the collapse of the illumination telecentric may vary depending on the illumination condition. Therefore, there has been a problem that the collapse of the illumination telecentric must be corrected according to the illumination condition.

  The present invention has been made in view of the above circumstances, an adjustment method of an illumination optical system that reduces the collapse of the telecentricity of the illumination optical system, an exposure apparatus that uses the illumination optical system adjusted using the adjustment method, and It is an object to provide a method and a device manufacturing method for manufacturing a device using the exposure apparatus.

In order to solve the above-mentioned problems, an illumination optical system adjustment method of the present invention includes a light source (1) that supplies a light beam and an optical integrator (10) on which the light beam from the light source is incident. Is a method of adjusting an illumination optical system (IS) that guides the luminous flux of light to an irradiated surface (LP), and is an optical member (2, 6, 8a, 9) disposed on an optical path between the light source and the optical integrator. ) To correct the collapse of the telecentricity of the light beam incident on the irradiated surface or its conjugate surface (LP3).
According to the present invention, the correction of the collapse of the telecentricity of the light beam incident on the irradiated surface or its conjugate surface is performed by adjusting the optical member disposed on the optical path between the light source and the optical integrator.
An exposure apparatus of the present invention is an exposure apparatus that transfers a pattern (DP) formed on a mask (R) onto a substrate (W), and is an illumination optical that is adjusted using the above-described adjustment method of the illumination optical system. It is characterized by comprising a system (40), a mask stage (41) for arranging the mask on the irradiated surface, and a substrate stage (47) for holding the substrate.
The device manufacturing method of the present invention is characterized by using the above exposure apparatus.
An exposure method of the present invention is an exposure method for transferring a pattern (DP) formed on a mask (R) onto a substrate (W), and the illumination optics adjusted using the above-described adjustment method of the illumination optical system A system (40) is used to illuminate the mask, and a pattern formed on the mask is transferred onto the substrate.

According to the present invention, the optical member disposed on the optical path between the light source and the optical integrator is adjusted to correct the collapse of the telecentricity of the light beam incident on the irradiated surface or its conjugate surface. The telecentricity collapse cannot be corrected sufficiently unlike the prior art, and there is an effect that it can be corrected appropriately according to the illumination conditions.
In addition, according to the present invention, the illumination light in which the collapse of the telecentricity is sufficiently corrected is applied to the mask, and the mask pattern is transferred to the substrate using this illumination light. As a result, a highly integrated device can be manufactured with a high yield.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an illumination optical system adjustment method, exposure apparatus and method, and device manufacturing method according to an embodiment of the present invention will be described in detail with reference to the drawings.

[Adjustment method of illumination optical system]
FIG. 1 is a diagram showing a schematic configuration of an illumination optical system in which an illumination optical system adjustment method according to an embodiment of the present invention is used. In the following description, an XYZ orthogonal coordinate system is set, and the positional relationship of each member will be described with reference to this XYZ orthogonal coordinate system. The XYZ orthogonal coordinate system is set so that the X axis and the Y axis are parallel to the irradiated surface LP, and the Z axis is set in a direction orthogonal to the irradiated surface LP. In the XYZ orthogonal coordinate system in the figure, the XY plane is actually set to a plane parallel to the horizontal plane, and the Z axis is set to the vertically upward direction.

  The illumination optical system IS of the present embodiment shown in FIG. 1 is configured to perform each of annular illumination, modified illumination, and normal illumination (normal illumination) using zero-order light. In the description, the case where the annular illumination is mainly performed will be described as an example. In FIG. 1, reference numeral 1 denotes a light source such as an ArF excimer laser light source (wavelength 193 nm), which emits a parallel light beam having a substantially rectangular cross section. In the present embodiment, it is assumed that the light source 1 emits a parallel light beam in the + Y direction as illustrated. The parallel light beam emitted from the light source 1 enters the movable mirror 2 provided in the beam matching unit (BMU), and is deflected by the movable mirror 2 in the + Z direction.

  The movable mirror 2 is configured to be capable of minute rotation around the X axis and a straight line included in the YZ plane and forming an angle of 45 degrees with respect to each of the Y axis and the Z axis. That is, the mirror surface angle with respect to the parallel light flux supplied from the light source 1 (hereinafter simply referred to as the angle of the movable mirror 2) can be slightly changed. The angle of the movable mirror 2 is adjusted by a first drive system 21 that operates based on a command from the control system 20. An angle sensor (not shown) that detects the actual angle of the movable mirror 2 is provided in the first drive system 21, and the detection result of this angle sensor is output to the control system 20.

  The light beam deflected in the + Z direction by the movable mirror 2 enters the diffractive optical element (DOE) 4 through the relay lens 3. The diffractive optical element 4 has, for example, a hexagonal shape, and element elements that diffract incident light to a desired angle are densely arranged in a plane perpendicular to the optical axis AX1 (in the XY plane). In FIG. 1, only one diffractive optical element 4 arranged on the optical path is shown, but actually, a plurality of diffractive optical elements including element elements having different outer shapes and diffraction characteristics are provided. Any one of these diffractive optical elements and the pinhole target 16 is disposed on the optical path. Note that none of these is arranged on the optical path when performing normal illumination.

  The pinhole target 16 is for forming a linear light beam, and is arranged on the optical path when correcting the telecentricity collapse of the illumination optical system IS (that is, the illumination telecentric collapse). This pinhole target 16 is formed by, for example, depositing Cr (chrome) on a transparent substrate to form a pinhole 16a, and only the light beam incident on the portion where the pinhole 16a is formed passes through the pinhole target 16. The light beam incident on the other part (the part where Cr (chromium) is deposited) is shielded. The pinhole target 16 is arranged so that the pinhole 16a is positioned on the optical axis AX1 when correcting the collapse of the illumination telecentricity. The replacement operation of the diffractive optical element 4, a plurality of diffractive optical elements (not shown), and the pinhole target 16 is performed by a second drive system 22 that operates based on a command from the control system 20.

  The light beam incident on the diffractive optical element 4 is diffracted along all directions at an equal angle with the optical axis AX1 as the center, and then enters the first zoom optical system 5. The first zoom optical system 5 is configured such that the zoom ratio can be continuously changed within a predetermined range while maintaining an afocal system (non-focus optical system). In FIG. 1, only two lenses 5 a and 5 b included in the first zoom optical system 5 are illustrated for simplification of illustration. These lenses 5a and 5b are configured to be movable along the direction of the optical axis AX1. Setting of the zoom ratio of the first zoom optical system 5 by the movement of the lenses 5a and 5b in the direction of the optical axis AX1 is performed by a third drive system 23 that operates based on a command from the control system 20. The light beam emitted from the first zoom optical system 5 enters the movable mirror 6 and is deflected in the + Y direction by the movable mirror 6.

  Similar to the movable mirror 2, the movable mirror 6 is configured to be capable of minute rotation about the X axis and about a straight line included in the YZ plane and forming an angle of 45 degrees with respect to each of the Y axis and the Z axis. ing. That is, the mirror surface angle with respect to the light beam emitted from the first zoom optical system 5 (hereinafter simply referred to as the angle of the movable mirror 6) can be slightly changed. The angle of the movable mirror 6 is adjusted by a fourth drive system 24 that operates based on a command from the control system 20. An angle sensor (not shown) that detects the actual angle of the movable mirror 6 is provided in the fourth drive system 24, and the detection result of this angle sensor is output to the control system 20.

  The light beam deflected in the + Y direction by the movable mirror 6 enters the first fly-eye lens 7. The first fly-eye lens 7 is an optical element composed of a large number of element lenses having a positive refractive power of a large number of regular hexagons arranged densely and in a plane perpendicular to the optical axis AX2 (in the ZX plane). In FIG. 1, only one first fly-eye lens 7 arranged on the optical path is shown, but in practice, a plurality of first fly-eye lenses including a plurality of element lenses having different outer shapes are provided. Any one of these first fly-eye lenses is disposed on the optical path.

  The light beam incident on the first fly-eye lens 7 is two-dimensionally divided in the ZX plane by a number of element lenses included in the first fly-eye lens 7, and one light source image is formed on the rear focal plane of each element lens. Is formed. Light beams from many light source images formed on the rear focal plane of the first fly-eye lens 7 enter the second zoom optical system 8. The second zoom optical system 8 includes a plurality of lenses, and the plurality of lenses are configured to be movable in the direction of the optical axis AX2. In the example shown in FIG. 1, the second zoom optical system 8 includes three lenses 8a to 8c, each configured to be movable in the direction of the optical axis AX2. Further, the lens 8a included in the second zoom optical system 8 is configured to be capable of minute movement in a direction (X direction or Z direction) intersecting the optical axis AX2.

  The second zoom optical system 8 is a relay optical system capable of continuously changing the focal length within a predetermined range, and includes a rear focal plane of the first fly-eye lens 7 and a second fly-eye lens 10 described later. The rear focal plane PL4 is optically almost conjugate. The focal length change and zoom ratio setting by the movement of the lenses 8a to 8c of the second zoom optical system 8 in the direction of the optical axis AX2, and the minute movement of the lens 8a in the direction intersecting the optical axis AX2 are controlled by the control system 20. This is performed by the fifth drive system 25 that operates based on this command. This fifth drive system 25 is provided with a position sensor (not shown) for detecting the positions of the lenses 8a to 8c in the optical axis AX2 direction and the position of the lens 8a in the ZX plane. Is output to the control system 20.

  The light beam that has passed through the second zoom optical system 8 enters the movable mirror 9 and is deflected in the −Z direction by the movable mirror 9. The movable mirror 9 is a straight line that is included around the X axis and in the YZ plane and forms an angle of 45 degrees with respect to each of the Y axis and the Z axis (this straight line is the straight line described for the movable mirrors 2 and 6). It is configured so as to be capable of micro-rotation around an angle of 90 degrees. That is, the mirror surface angle with respect to the light beam emitted from the second zoom optical system 8 (hereinafter simply referred to as the angle of the movable mirror 9) can be slightly changed. The angle of the movable mirror 9 is adjusted by a sixth drive system 26 that operates based on a command from the control system 20. Further, an angle sensor (not shown) for detecting the actual angle of the movable mirror 9 is provided in the sixth drive system 26, and the detection result of this angle sensor is output to the control system 20.

  The light beam deflected in the −Z direction by the movable mirror 9 illuminates the incident surface PL3 of the second fly-eye lens 10 as an optical integrator in a superimposed manner. Similar to the first fly-eye lens 7, the second fly-eye lens 10 is configured by arranging a large number of element lenses having positive refractive power in a plane (in the XY plane) orthogonal to the optical axis AX3. Yes. Each element lens constituting the second fly-eye lens 10 has a rectangular cross section similar to the shape of the illumination field to be formed on the irradiated surface LP.

  The light beam incident on the second fly-eye lens 10 is two-dimensionally divided in the ZX plane by a large number of element lenses, and the first fly-eye lens 7 has a rear focal plane PL4 of each element lens on which the light beams are incident. A large number of light source images corresponding to the number of element lenses are formed. In this way, on the rear focal plane PL4 of the second fly-eye lens 10, the same ring-shaped multiple light sources (secondary light sources) as the illumination field formed by the light flux incident on the second fly-eye lens 10 are formed.

  A sensor 17 is disposed on the incident surface PL3 side of the second fly-eye lens 10 so as to be able to advance and retreat with respect to the optical path. This sensor 17 includes, for example, a two-dimensional CCD, is disposed on the optical path when correcting the collapse of the illumination telecentricity, and is used to detect the incident position of the light beam on the incident surface PL3 of the second fly-eye lens 10. . The detection result of the sensor 17 is output to the control system 20. When the sensor 17 is disposed on the optical path, the above-described pinhole target 16 is also disposed on the optical path. The advance / retreat operation of the sensor 17 with respect to the optical path is performed by a seventh drive system 27 that operates based on a command from the control system 20.

  On the rear focal plane PL4 of the second fly-eye lens 10, that is, the pupil plane of the illumination optical system IS, the aperture stop plate 11 is rotatably arranged by the eighth drive system 28. FIG. 2 is a front view showing an example of the aperture stop plate 11. As shown in FIG. 2, the aperture stop plate 11 is a disc configured to be rotatable around the rotation axis O, and includes a circular aperture stop 11 a for normal illumination, an aperture stop 11 b for annular illumination, and quadrupole deformation. An aperture stop 11c for illumination (quadrupole illumination) and a small circular aperture stop 11d for a small coherence factor (σ value) are formed along the circumferential direction. 2 represents the size of the circular aperture stop 11a for normal illumination, and is shown for comparison with the size of the aperture stops 11b to 11d. In FIG. 2, only four different aperture stops are shown. For example, a plurality of aperture stops 11b having different ring zone ratios (ratio of the outer edge radius to the inner edge radius) are formed. Also good. The same applies to the aperture stop 11c. The aperture stop plate 11 may be omitted when a desired exposure light distribution is formed on the rear focal plane PL4 of the second fly-eye lens 10.

  Of the light beams emitted from the secondary light source formed on the rear focal plane PL4 of the second fly-eye lens 10, the light beam that has passed through any of the aperture stops formed on the aperture stop plate 11 is the first relay optical. The irradiated surface LP is uniformly and uniformly illuminated through the system 12, the field stop plate 13, the second relay optical system 14, and the condenser optical system 15 in this order. The field stop plate 13 defines the cross-sectional shape (cross-sectional shape in the XY plane) of the light beam applied to the irradiated surface LP, and the irradiated surface is formed by the second relay optical system 14 and the condenser optical system 15. It is optically conjugate with LP. Further, the incident surface LP3 of the second fly's eye lens 10 and the irradiated surface LP are set so as to be optically conjugate.

  The control system 20 drives the first drive system 21, the fourth drive system 24, the fifth drive system 25, and the sixth drive system 26 described above to adjust the angles of the movable mirrors 2, 6, and 9, and the second zoom. The position in the direction intersecting the optical axis AX2 of the lens 8a included in the optical system 8 is adjusted. Further, the second drive system 22, the seventh drive system 27, the eighth drive system 28, etc. are driven to arrange the diffractive optical element 4, the pinhole target 16, the first fly-eye lens 7, and the sensor 17 on the optical path. In addition, the arrangement of any one of the aperture stops 11a to 11d on the optical path is controlled. Further, the control system 20 drives the third drive system 23 and the fifth drive system 25 to set the zoom ratio of the first zoom optical system 5 and the focal length and zoom ratio of the second zoom optical system 8.

  Further, the control system 20 is provided with a storage unit 20a including a magnetic storage device such as a semiconductor memory or a hard disk. The storage unit 20a detects the detection results of the angle sensors provided in the first drive system 21, the fourth drive system 24, and the sixth drive system 26, and the detections of the position sensors provided in the fifth drive system 25. The result is stored in association with the illumination condition set in the illumination optical system IS. The control system 20 associates the illumination conditions set in the illumination optical system IS with various detection results.

  Next, a change in the cross-sectional shape of the light beam along the optical axis in the illumination optical system IS of the present embodiment will be briefly described by taking an example of performing annular illumination. FIG. 3 is a diagram illustrating an example of a change in cross-sectional shape of a light beam when performing annular illumination. In FIG. 3, the same components as those shown in FIG. 1 are denoted by the same reference numerals. Further, the optical axes AX1 to AX3 are shown in a straight line, and the movable mirrors 2, 6, and 9 are not shown. Furthermore, in the following description, the optical axes AX1 to AX3 in FIG.

  As shown in FIG. 3, it is assumed that a light beam having a uniform illuminance distribution and a circular cross section is guided to the incident surface PL1 of the diffractive optical element 4. When such a light beam enters the diffractive optical element 4, the incident light beam is two-dimensionally divided by a large number of element elements included in the diffractive optical element 4 and diffracted at a desired angle. Therefore, the light beams emitted from the respective element elements included in the diffractive optical element 4 are deflected along all directions at an equal angle with the optical axis AX (optical axis AX1) as the center, and are then applied to the first zoom optical system 5. Incident. In this way, the diffractive optical element 4 converts the incident light beam into a substantially annular light beam.

  The light beam incident on the first zoom optical system 5 forms a ring-shaped (annular) light source image on the pupil plane PL2. The light from the ring-shaped light source image is emitted from the first zoom optical system 5 as a substantially parallel light flux and enters the first fly-eye lens 7. At this time, the light beam enters the incident surface of the first fly-eye lens 7 from an oblique direction substantially symmetrically with respect to the optical axis AX (optical axis AX2). In other words, the light flux is obliquely incident along all directions at an equal angle around the optical axis AX.

  The light beam incident on the first fly-eye lens 7 is two-dimensionally divided by a number of element lenses included in the first fly-eye lens 7, and one ring-shaped light source image is formed on the rear focal plane of each element lens. It is formed. Light beams from a large number of ring-shaped light source images formed on the rear focal plane of the first fly-eye lens 7 illuminate the second fly-eye lens 10 in a superimposed manner after passing through the second zoom optical system 8. Therefore, a regular hexagonal illumination field similar to the cross-sectional shape of each element lens of the first fly-eye lens 7 is equidistant from the optical axis AX (optical axis AX3) on the incident surface PL3 of the second fly-eye lens 10. An infinite number of illumination fields arranged at positions, that is, an annular illumination field centered on the optical axis AX is formed.

  The light beam incident on the second fly-eye lens 10 is two-dimensionally divided by a large number of element lenses, and a large number of element lenses of the first fly-eye lens 7 are formed on the rear focal plane of each element lens on which the light beam is incident. Are respectively formed. In this way, on the rear focal plane PL4 of the second fly-eye lens 10, the same ring-shaped multiple light sources (secondary light sources) as the illumination field formed by the light flux incident on the second fly-eye lens 10 are formed. The luminous flux emitted from each of the annular secondary light sources is irradiated through the first relay optical system 12, the field stop plate 13, the second relay optical system 14, and the condenser optical system 15 shown in FIG. The LP is uniformly illuminated in a superimposed manner.

  Next, a method for adjusting the illumination optical system IS in the above configuration will be described. FIG. 4 is a flowchart showing a method for adjusting an illumination optical system according to an embodiment of the present invention. The adjustment of the illumination optical system IS according to the flowchart shown in FIG. 4 is a final adjustment process in which the optical performance of the illumination optical system IS is driven after the illumination optical system IS including the optical members shown in FIG. Or it is performed at the time of maintenance of irregular illumination optical system IS. The adjustment method shown in FIG. 4 is a method for correcting the collapse of the illumination telecentric of the illumination optical system IS by adjusting the angles of the movable mirrors 2, 6, and 9.

  When adjusting the illumination optical system IS, the control system 20 first drives the second drive system 22 to place the pinhole target 16 on the optical path. At this time, when the diffractive optical element 4 is disposed on the optical path, the diffractive optical element 4 on the optical path is retracted from the optical path, and the pinhole target is arranged so that the pinhole 16a is disposed on the optical axis AX1. 16 is arranged on the optical path. The control system 20 drives the seventh drive system 27 to place the sensor 17 on the optical path. Thereby, the sensor 17 is arrange | positioned at the entrance plane PL3 side of the 2nd fly eye lens 10 (step S11).

  When the arrangement of the pinhole target 16 and the sensor 17 is completed, the control system 20 first outputs a control signal to the first drive system 21 to adjust the angle of the movable mirror 2 to a predetermined angle (step S12). When the adjustment of the angle of the movable mirror 2 is completed, the control system 20 outputs a control signal to the light source 1 to emit a light beam. The light beam emitted from the light source 1 is deflected in the + Z direction by the movable mirror 2, passes through the relay lens optical system 3, and then enters the pinhole target 16 disposed on the optical path. When a light beam enters the pinhole target 16, a linear light beam is formed from the light beam that has passed through the pinhole 16a.

  This linear light beam is deflected in the + Y direction by the movable mirror 6 via the first zoom optical system 5 and then enters the movable mirror 9 via the first fly-eye lens 7 and the second zoom optical system 8 in this order. To do. The light beam incident on the movable mirror 9 is deflected in the −Z direction and then incident on the sensor 17 disposed on the incident surface PL3 side of the second fly-eye lens 10. The sensor 17 detects the incident position (incident position in the XY plane) of this light beam and outputs the detection result to the control system 20.

  In a state where the detection result from the sensor 17 is input, the control system 20 outputs a control signal to the third drive system 23 to vary the zoom ratio of the first zoom optical system 5 within a variable range. (Step S13). That is, the control system 20 varies the zoom ratio of the first zoom optical system 5 from the minimum zoom ratio to the maximum zoom ratio. While changing the zoom ratio of the first zoom optical system 5, the control system 20 constantly monitors the detection result output from the sensor 17.

  The control system 20 determines whether or not the incident position of the light beam on the sensor 17 has changed in accordance with the change in the zoom ratio of the first zoom optical system 5 (step S14). If the result is “YES”), the process returns to step S12, the angle of the movable mirror 2 is adjusted again, and the magnification of the first zoom optical system 5 is changed again in the same manner, so that the incident position of the light flux on the sensor 17 is changed. Determine whether it has changed. If the incident position of the light beam on the sensor 17 does not change even if the zoom ratio of the first zoom optical system 5 is changed over the entire variable range, or if the change is smaller than a predetermined allowable amount, step The determination result in S14 is “NO”. As a result of the above processing, the optical axis between the movable mirror 2 and the movable mirror 6 is in a state substantially coincident with the optical axis AX1.

  Next, the control system 20 outputs a control signal to the fourth drive system 24 to adjust the angle of the movable mirror 6 to a predetermined angle (step S15), and the detection result from the sensor 17 is input. Thus, a control signal is output to the fifth drive system 25, and the zoom ratio of the second zoom optical system 8 is varied within a variable range (step S16). That is, the control system 20 varies the zoom ratio of the second zoom optical system 8 from the minimum zoom ratio to the maximum zoom ratio. While the zoom ratio of the second zoom optical system 8 is varied, the control system 20 constantly monitors the detection result output from the sensor 17.

  The control system 20 determines whether or not the incident position of the light beam on the sensor 17 has changed in accordance with the change in the zoom ratio of the second zoom optical system 8 (step S17). If the result is “YES”), the process returns to step S15, the angle of the movable mirror 6 is adjusted again, and then the magnification of the second zoom optical system 8 is changed again in the same manner, so that the incident position of the light flux on the sensor 17 is changed. Determine whether it has changed. If the incident position of the light beam on the sensor 17 does not change even if the zoom ratio of the second zoom optical system 8 is changed over the entire variable range, or if the change is smaller than a predetermined allowable amount, step S17. The determination result is “NO”. As a result of the above processing, the optical axis between the movable mirror 6 and the movable mirror 9 is substantially coincident with the optical axis AX2.

  When the above processing is completed, the control system 20 outputs a control signal to the sixth drive system 26 to adjust the angle of the movable mirror 9 so that the linear light beam enters the center position of the second fly-eye lens 10. To. By performing the above processing, the position at which the light beam enters the sensor 17 even when the variable magnification of at least one of the first zoom optical system 5 and the second zoom optical system 8 is varied, that is, the second fly-eye lens 10 The incident position of the light beam on the incident surface PL3 does not change. Thereby, the collapse of the illumination telecentric is corrected.

  Through the above processing, the illumination telecentric of the illumination optical system IS is adjusted. When the adjustment is completed, the control system 20 indicates the angles of the movable mirrors 2, 6, 9 detected by the angle sensors provided in the first drive system 21, the fourth drive system 24, and the sixth drive system 26. Is stored in the memory 20a. In the above description, the case where the movable mirrors 2, 6, 9 are adjusted to correct the collapse of the illumination telecentric has been described, but instead of these adjustments, the lens 8 a ( It is also possible to correct the collapse of the illumination telecentric by adjusting the position in the direction intersecting the optical axis AX2 (one or a plurality of sheets). Further, in addition to the adjustment of the movable mirrors 2, 6 and 9, the lens 8 a may be adjusted to correct the collapse of the illumination telecentricity. When the adjustment of the lens 8a is performed, information indicating the position of the lens 8a that has been adjusted in the ZX plane is stored in the memory 20a.

  For example, when the illumination condition of the illumination optical system IS is changed by exchanging the first fly-eye lens 7 disposed on the optical path, the illumination telecentric may be slightly broken. For this reason, it is preferable that the process shown in FIG. 4 is performed for each illumination condition in advance, and the optimum angles of the movable mirrors 2, 6, 9 and the position of the lens 8a for each illumination condition are stored in the memory 20a. Then, when actually irradiating the irradiated surface LP, information corresponding to the illumination condition set in the illumination optical system IS is read, and the angles of the movable mirrors 2, 6, 9 and the ZX of the lens 8a are read based on this information. It is desirable to adjust the position in the plane. Thereby, the collapse of the telecentricity of the illumination optical system IS can be appropriately corrected according to the illumination conditions.

  The adjustment method of the illumination optical system according to the embodiment of the present invention has been described above. However, the adjustment method described above is not limited to the illumination optical system IS having the configuration shown in FIG. can do. Hereinafter, two examples of the illumination optical system to which the adjustment method of the present invention can be applied will be described.

  FIG. 5 is a diagram showing a first configuration example of an illumination optical system to which the adjustment method of the present invention can be applied. The overall configuration of the illumination optical system shown in FIG. 5 is substantially the same as the configuration of the illumination optical system IS shown in FIG. 1, but includes a fly-eye lens 30 instead of the diffractive optical element 4 in FIG. The difference is that a diffractive optical element 31 is provided instead of the first fly-eye lens 7 in FIG. In FIG. 5, a portion having a configuration different from that of the illumination optical system IS shown in FIG. 1 is extracted and illustrated, and like FIG. 3, the same optical member as shown in FIG. The same reference numerals are attached, and the optical axes AX1 to AX3 are aligned to form the optical axis AX, and the movable mirrors 2, 6, and 9 are not shown.

  The fly-eye lens 30 has the same configuration as that of the first fly-eye lens 7 in FIG. 1, and has a number of regular hexagonal positive arrays that are densely arranged in a plane perpendicular to the optical axis AX (optical axis AX1). It is an optical element composed of a microlens having refractive power. Although only one fly-eye lens 30 is shown in FIG. 5, a plurality of fly-eye lenses each having a plurality of element lenses having different outer shapes are actually provided. Any one of the pinhole targets 16 inside is arranged on the optical path. Note that none of these is arranged on the optical path when performing normal illumination.

  Further, the diffractive optical element 31 is the same as the diffractive optical element 4 in FIG. 1, and has, for example, a hexagonal shape, and an element element that diffracts incident light to a desired angle is perpendicular to the optical axis AX2. In a dense plane (in the XY plane). In FIG. 5, only one diffractive optical element 31 arranged on the optical path is shown, but actually, a plurality of diffractive optical elements including element elements having different outer shapes and diffraction characteristics are provided. Any one of these diffractive optical elements is disposed on the optical path.

  Next, a change in the cross-sectional shape of the light beam along the optical axis in the illumination optical system shown in FIG. 5 will be briefly described by taking an example of performing annular illumination. The light beam incident on the incident surface of the fly-eye lens 30 is two-dimensionally divided in the XY plane by a plurality of element lenses included in the fly-eye lens 30, and one light source image is formed on the rear focal plane of each element lens. Is formed. Light beams from a large number of light source images formed on the rear focal plane of the fly-eye lens 30 are incident on the first zoom optical system 5 as divergent light beams each having a regular hexagonal cross section.

  The light beam that has passed through the first zoom optical system 5 enters the diffractive optical element 31. At this time, the divergent light beam from each light source image formed on the rear focal plane of the fly-eye lens 30 converges on the diffractive surface of the diffractive optical element 31 while maintaining a regular hexagonal cross section, for example. The first zoom optical system 5 optically conjugates the rear focal plane of the fly-eye lens 30 and the diffractive surface of the diffractive optical element 31, and focuses the light on one point on the diffractive optical element 31. The numerical aperture of the light beam changes depending on the magnification of the first zoom optical system.

  The light beam that has passed through the diffractive optical element 31 forms a ring-shaped illumination field on the rear focal plane of the second zoom optical system 8 and thus on the incident surface LP3 of the second fly-eye lens 10. The outer diameter of the annular illumination field changes depending on the focal length of the second zoom optical system 8. As described above, the second zoom optical system 8 substantially has a Fourier transform relationship between the diffractive optical element 31 and the incident surface of the second fly-eye lens 10. The light beam incident on the second fly-eye lens 10 is two-dimensionally divided by a number of element lenses, and is formed by the light beam incident on the fly-eye lens 10 on the rear focal plane LP4 of each element lens on which the light beam is incident. An annular secondary light source is formed which is the same as the illumination field. The luminous flux from the annular secondary light source formed on the rear focal plane LP4 of the fly-eye lens 10 is a first relay optical system 12, a field stop plate 13, a second relay optical system 14 and a condenser shown in FIG. The illuminated surface LP is uniformly and uniformly illuminated through the optical system 15 in order.

  The illumination optical system shown in FIGS. 1 and 5 described above includes one diffractive optical element and one fly-eye lens on the optical path from the light source 1 to the second fly-eye lens 10. That is, the illumination optical system IS shown in FIG. 1 includes the diffractive optical element 4 and the first fly-eye lens 7, and the illumination optical system shown in FIG. 5 includes the fly-eye lens 30 and the diffractive optical element 31. . The second configuration example of the illumination optical system described below is a configuration in which any one of these is omitted. That is, in the illumination optical system IS shown in FIG. 1, the first fly-eye lens 7 is omitted, and in the illumination optical system shown in FIG. 5, the fly-eye lens 31 is omitted. The illumination optical system having such a configuration can also correct the collapse of the illumination telecentricity using an adjustment method similar to the adjustment method described with reference to FIG.

  The adjustment method of the illumination optical system according to the embodiment of the present invention has been described above. However, the adjustment method of the present invention is not limited to the above embodiment, and can be freely changed within the scope of the present invention. For example, in the above-described embodiment, when correcting the collapse of the illumination telecentricity, the sensor 17 is disposed on the incident surface PL3 of the first fly-eye lens 10 that is a conjugate surface of the irradiated surface LP to detect a change in the position of the incident light beam. However, the sensor 17 may be disposed on the irradiated surface (an object surface or an image surface of the projection optical system PL described later) LP to detect a change in the position of the incident light beam.

  In addition, a pinhole is disposed on the object plane side of the projection optical system PL, particularly a position slightly deviated from the object plane (for example, the upper surface of the reticle), and a sensor is disposed on the image plane to detect a change in the position of the incident light beam. It may be. Further, a pinhole is arranged on the image plane of the projection optical system PL, and light passing through the pinhole is passed through the objective optical system to an image pickup element arranged at a position conjugate with the pupil plane of the projection optical system PL. You may make it guide to an imaging surface and may detect the position change of incident light beam. Further, the illumination telecentric may be detected and adjusted by a detection (measurement) system of a method disclosed in JP-A-2002-14005.

  In the above embodiment, the light beam supplied from the light source 1 is deflected three times using the movable mirrors 2, 6, and 9 to irradiate the irradiated surface LP, but the light beam from the light source 1 is deflected. The number of times is appropriately increased or decreased according to the device configuration and installation conditions of the illumination optical system. For example, a reflection mirror may be provided on the optical path from the light source 1 to the movable mirror 2 to increase the number of deflections, and the movable mirror 6 may be omitted to reduce the number of deflections. Even if the number of times of deflection is increased or decreased, the collapse of the illumination telecentricity can be corrected using the adjustment method of the present invention described above. In the above embodiment, the movable mirrors 2, 6, and 9 are used as the deflecting members. However, the present invention is not limited to these mirrors, and a prism such as a right-angle prism can also be used.

  Furthermore, in the above embodiment, the pinhole target 16 and the sensor 17 are arranged on the optical path when correcting the collapse of the illumination telecentricity. However, it is not always necessary to use these when correcting the illumination telecentricity. Instead of using these, for example, a part of the light beam via the second zoom optical system 8 or a part of the light beam deflected by the movable mirror 9 is branched, and the branched light beam is reduced and led to an imaging device such as a CCD. You may make it detect the change of the imaging position of the reduction image of the light beam with respect to the imaging surface of an image sensor. However, the imaging surface of the image sensor needs to be conjugate with the illuminated surface LP, and depending on the amount of incident light flux to the image sensor, a light reducing member such as an ND filter that reduces the incident light flux to the image sensor is required. become. Further, instead of the pinhole 16a, a diffractive optical element (DOE) capable of forming an ultrafine light beam may be used.

[Exposure apparatus and exposure method]
Next, an exposure apparatus and an exposure method according to an embodiment of the present invention will be described in detail. FIG. 6 is a view showing the schematic arrangement of an exposure apparatus according to an embodiment of the present invention. The exposure apparatus shown in FIG. 6 is a so-called step-and-scan exposure apparatus that sequentially transfers an image of a pattern formed on the reticle R onto the wafer W while moving the reticle R and the wafer W synchronously.

In FIG. 6, reference numeral 40 denotes an ultrahigh pressure mercury lamp that emits g-line (wavelength 436 nm), i-line (wavelength 365 nm), or KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), or F ₂ laser ( The illumination optical system includes a light source having a wavelength of 157 nm, etc., emits illumination light IL shaped into a predetermined shape while making the light intensity distribution of light emitted from these light sources uniform. The illumination optical system 40 is, for example, the illumination optical system IS shown in FIG. 1, and is adjusted at the time of manufacture or regularly or irregularly using the adjustment method described above. The control system 20 and the storage unit 20a in FIG. 1 are provided in the main control system 45 in FIG. 6, and under the control of the main control system 45, setting of illumination conditions for the illumination optical system IS and illumination Telecentric adjustments are made.

  Reference numeral 41 denotes a reticle stage on which a reticle R as a mask is placed, which can be finely moved in the direction of the optical axis AX of the projection optical system PL, and can be two-dimensionally moved and finely rotated in a plane perpendicular to the optical axis AX. Configured. A movable mirror 42 is attached to one end of the reticle stage 41, and a laser interferometer 44 is disposed at a position facing the mirror surface of the movable mirror 42. A fixed mirror 43 is attached to the illumination optical system 40 described above. The fixed mirror 43 may be attached to the projection optical system PL. The laser interferometer 44 irradiates the movable mirror 42 and the fixed mirror 43 with laser light, detects the interference light obtained by causing each reflected light to interfere, and measures the position of the reticle stage 41 in the XY plane.

  Although the illustration is simplified in FIG. 6, the movable mirror 42 includes a movable mirror having a mirror surface perpendicular to the X axis and a movable mirror having a mirror surface perpendicular to the Y axis. The laser interferometer 44 includes two Y-axis laser interferometers that irradiate the moving mirror 42 with a laser beam along the Y-axis and an X-axis laser that irradiates the moving mirror 42 with a laser beam along the X-axis. The X and Y coordinates of the reticle stage 41 are measured by one laser interferometer for the Y axis and one laser interferometer for the X axis. Further, the rotation angle of the reticle stage 41 is measured by the difference between the measurement values of the two Y-axis laser interferometers. Information on the X coordinate, Y coordinate, and rotation angle of the reticle stage 41 detected by the laser interferometer 44 is supplied to the main control system 45. The main control system 45 outputs a control signal to the drive system 46 while monitoring the supplied stage position information, and controls the positioning operation of the reticle stage 41.

  The reticle R placed on the reticle stage 41 has a device pattern DP such as a semiconductor element or a liquid crystal display element formed of chromium or the like on the surface of a transparent glass substrate. The reticle stage 41 arranges the surface on which the device pattern DP is formed on the irradiated surface LP shown in FIG. When the reticle R is illuminated by the illumination light IL emitted from the illumination optical system 40, an image of the device pattern DP formed on the reticle R is projected onto the wafer W via the projection optical system PL. The wafer W is placed on the wafer stage 47. Note that the surface (pattern surface) on which the device pattern DP of the reticle R is formed and the surface of the wafer W are optically conjugate with respect to the projection optical system PL.

  The wafer stage 47 is an XY stage that moves the wafer W in the XY plane, a Z stage that moves the wafer W in the Z-axis direction, a stage that rotates the wafer W in the XY plane, and an angle with respect to the Z-axis to change the XY. The stage is configured to adjust the inclination of the wafer W with respect to the plane. A movable mirror 48 having a length longer than the movable range of the wafer stage 47 is attached to one end of the upper surface of the wafer stage 47, and a laser interferometer 50 is disposed at a position facing the mirror surface of the movable mirror 48. Further, a fixed mirror 49 is attached to the projection optical system PL described above. The laser interferometer 50 irradiates the movable mirror 48 and the fixed mirror 49 with laser light, detects the interference light obtained by causing the reflected lights to interfere, and measures the position of the wafer stage 47 in the XY plane. .

  Although the illustration is simplified in FIG. 6, the movable mirror 48 includes a movable mirror having a mirror surface perpendicular to the X axis and a movable mirror having a mirror surface perpendicular to the Y axis. The laser interferometer 50 includes two Y-axis laser interferometers that irradiate the moving mirror 48 with a laser beam along the Y-axis and an X-axis that irradiates the movable mirror 48 with a laser beam along the X-axis. The X and Y coordinates of the wafer stage 47 are measured by one laser interferometer for the Y axis and one laser interferometer for the X axis. Further, the rotation angle of the wafer stage 47 is measured by the difference between the measurement values of the two Y-axis laser interferometers. Information on the X coordinate, Y coordinate, and rotation angle of the wafer stage 47 measured by the laser interferometer 50 is supplied to the main control system 45. The main control system 45 outputs a control signal to the drive system 51 while monitoring the supplied stage position information, and controls the positioning operation of the wafer stage 47.

  When the image of the device pattern DP formed on the reticle R is transferred onto the wafer W, first, the main control system 45 measures the accurate position information of the reticle R using a reticle alignment system (not shown) and also performs wafer alignment. After measuring the accurate position information of the wafer W using the system, the relative positions of the reticle R and the wafer W are adjusted based on these measurement results and the measurement results of the laser interferometer 44 and the laser interferometer 50. . Next, a control signal is output to the drive system 46 and the drive system 51 to start movement of the reticle R and the wafer W, and the reticle R is irradiated with slit-shaped illumination light IL. Thereafter, while the detection results of the laser interferometer 44 and the laser interferometer 50 are monitored, the reticle R and the wafer W are moved synchronously to sequentially transfer the device pattern DP onto the wafer W.

[Device manufacturing method]
Next, an embodiment of a device manufacturing method using the exposure apparatus and the exposure method according to the embodiment of the present invention in the lithography process will be described. FIG. 7 is a flowchart showing a manufacturing example of a device (a semiconductor chip such as an IC or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc.). As shown in FIG. 7, first, in step S20 (design step), device function / performance design (for example, circuit design of a semiconductor device) is performed, and a pattern design for realizing the function is performed. Subsequently, in step S21 (mask manufacturing step), a mask (reticle) on which the designed circuit pattern is formed is manufactured. On the other hand, in step S22 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

  Next, in step S23 (wafer processing step), using the mask and wafer prepared in step S20 to step S22, an actual circuit or the like is formed on the wafer by lithography or the like, as will be described later. Next, in step S24 (device assembly step), device assembly is performed using the wafer processed in step S23. Step S24 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary. Finally, in step S25 (inspection step), inspections such as an operation confirmation test and a durability test of the device manufactured in step S24 are performed. After these steps, the device is completed and shipped.

  FIG. 8 is a diagram showing an example of a detailed flow of step S23 of FIG. 7 in the case of a semiconductor device. In FIG. 8, in step S31 (oxidation step), the surface of the wafer is oxidized. In step S32 (CVD step), an insulating film is formed on the wafer surface. In step S33 (electrode formation step), an electrode is formed on the wafer by vapor deposition. In step S34 (ion implantation step), ions are implanted into the wafer. Each of the above steps S31 to S34 constitutes a pretreatment process at each stage of the wafer processing, and is selected and executed according to a necessary process at each stage.

  At each stage of the wafer process, when the above-described pre-processing step is completed, the post-processing step is executed as follows. In this post-processing process, first, in step S35 (resist formation step), a photosensitive agent is applied to the wafer. Subsequently, in step S36 (exposure step), the circuit pattern of the mask is transferred to the wafer by the lithography system (exposure apparatus) and the exposure method described above. Next, in step S37 (developing step), the exposed wafer is developed, and in step S38 (etching step), the exposed members other than the portion where the resist remains are removed by etching. In step S39 (resist removal step), the resist that has become unnecessary after the etching is removed. By repeatedly performing these pre-processing steps and post-processing steps, multiple circuit patterns are formed on the wafer.

  If the device manufacturing method of the present embodiment described above is used, in the exposure step (step S36), the wafer W is exposed with the illumination light IL having a constant illuminance distribution and corrected illumination telecentricity, and variation in the accumulated exposure amount. Therefore, a fine pattern formed on the reticle R can be accurately transferred onto the wafer W. As a result, a highly integrated device having a minimum line width of about 0.1 μm can be obtained with a high yield. Can be produced.

As mentioned above, although embodiment of this invention was described, this invention is not restrict | limited to the said embodiment, It can change freely within the scope of the present invention. For example, in the above-described embodiment, the step-and-scan type exposure apparatus has been described as an example, but the present invention is also applicable to a step-and-repeat type exposure apparatus. The light source included in the illumination optical system 40 of the exposure apparatus of the present embodiment is not limited to an ultrahigh pressure mercury lamp, a KrF excimer laser, an ArF excimer laser, or an F ₂ laser, but also a charged particle beam such as an X-ray or an electron beam. Can be used. For example, when an electron beam is used, thermionic emission type lanthanum hexabolite (LaB ₆ ) or tantalum (Ta) can be used as the electron gun.

  Furthermore, a single wavelength laser beam in the infrared region or visible region oscillated from a DFB semiconductor laser or fiber laser as a light source is amplified by, for example, a fiber amplifier doped with erbium (or both erbium and yttrium), and nonlinear optics You may use the harmonic which wavelength-converted into the ultraviolet light using the crystal | crystallization. For example, if the oscillation wavelength of a single wavelength laser is in the range of 1.51 to 1.59 μm, the generated wavelength is in the range of 189 to 199 nm, the eighth harmonic, or the generated wavelength is in the range of 151 to 159 nm. A 10th harmonic is output.

In particular, when the oscillation wavelength is in the range of 1.544 to 1.553 μm, the 8th harmonic in the range of 193 to 194 nm, that is, ultraviolet light having substantially the same wavelength as the ArF excimer laser light is obtained. When the oscillation wavelength is in the range of 1.57 to 1.58 μm, the 10th harmonic wave in the range of 157 to 158 nm, that is, ultraviolet light having substantially the same wavelength as the F ₂ laser light is obtained. Further, if the oscillation wavelength is in the range of 1.03 to 1.12 μm, the seventh harmonic whose output wavelength is in the range of 147 to 160 nm is output, and in particular, the oscillation wavelength is in the range of 1.099 to 1.106 μm. If it is inside, the 7th harmonic in the range of 157 to 158 μm, that is, ultraviolet light having substantially the same wavelength as the F ₂ laser light is obtained. In this case, for example, an yttrium-doped fiber laser can be used as the single wavelength oscillation laser.

Further, the relay lens 3, the diffractive optical grating 4, the first zoom optical system 5, the first fly eye lens 7, the second zoom optical system 8, the second fly eye lens 10, and the first relay provided in the illumination optical system described above. As optical elements provided in the optical system 12, the second relay optical system 14, the condenser optical system 15, and the projection optical system PL, fluorite (calcium fluoride: CaF ₂ ) according to the wavelength of the illumination light IL, Magnesium fluoride (MgF ₂ ), lithium fluoride (LiF), barium fluoride (BaF ₂ ), strontium fluoride (SrF ₂ ), LiCAF (corkyrite: LiCaAlF ₆ ), LiSAF (LiSrAlF ₆ ), LiMgAlF ₆ , LiBeAlF _{6 , KMgF 3, KCaF 3, KSrF} 3 fluoride crystal or mixed crystal thereof, such as, the fluorine Ya It is selected from an optical material which transmits vacuum ultraviolet light quartz glass or the like material doped with the arsenide. The quartz glass doped with a predetermined substance has a reduced transmittance when the wavelength of the exposure light is shorter than about 150 nm. Therefore, when vacuum ultraviolet light having a wavelength of about 150 nm or less is used as the illumination light IL, an optical element is used. As optical materials, fluorite (calcium fluoride), magnesium fluoride, lithium fluoride, barium fluoride, strontium fluoride, LiCAF (corkylite), LiSAF (LiSrAlF ₆ ), LiMgAlF ₆ , LiBeAlF ₆ , KMgF ₃ , Fluoride crystals such as KCaF ₃ and KSrF ₃ or mixed crystals thereof are used.

  The present invention is not limited to an exposure apparatus used for manufacturing a semiconductor element, but also used for manufacturing a display including a liquid crystal display element (LCD) or the like, and an exposure apparatus for transferring a device pattern onto a glass plate, a thin film magnetic head The present invention can also be applied to an exposure apparatus that is used for manufacturing and transfers a device pattern onto a ceramic wafer, and an exposure apparatus that is used to manufacture an image sensor such as a CCD. Furthermore, in an exposure apparatus that transfers a circuit pattern onto a glass substrate or a silicon wafer in order to manufacture a reticle or mask used in an optical exposure apparatus, EUV exposure apparatus, X-ray exposure apparatus, electron beam exposure apparatus, or the like. The present invention can also be applied. Here, in an exposure apparatus using DUV (far ultraviolet) light, VUV (vacuum ultraviolet) light, or the like, a transmission type reticle is generally used. As a reticle substrate, quartz glass, fluorine-doped quartz glass, fluorite, Magnesium fluoride or quartz is used. Further, in a proximity type X-ray exposure apparatus or an electron beam exposure apparatus, a transmission mask (stencil mask, membrane mask) is used, and a silicon wafer or the like is used as a mask substrate.

  Moreover, in order to manufacture reticles or masks used not only in devices such as semiconductor elements but also in light exposure apparatuses, EUV exposure apparatuses, X-ray exposure apparatuses, electron beam exposure apparatuses, etc., from mother reticles to glass substrates and silicon The present invention can also be applied to an exposure apparatus that transfers a circuit pattern to a wafer or the like. Here, in an exposure apparatus using DUV (deep ultraviolet), VUV (vacuum ultraviolet) light, or the like, a transmission type reticle is generally used. As a reticle substrate, quartz glass, fluorine-doped quartz glass, fluorite, Magnesium fluoride or quartz is used. In proximity type X-ray exposure apparatuses, electron beam exposure apparatuses, and the like, a transmissive mask (stencil mask, membrane mask) is used, and a silicon wafer or the like is used as a mask substrate. Such an exposure apparatus is disclosed in WO99 / 34255, WO99 / 50712, WO99 / 66370, JP-A-11-194479, JP-A2000-12453, JP-A-2000-29202, and the like. .

It is a figure which shows the outline of a structure of the illumination optical system by which the adjustment method of the illumination optical system by one Embodiment of this invention is used. 3 is a front view showing an example of an aperture stop plate 11. FIG. It is a figure which shows an example of the change of the cross-sectional shape of the light beam in the case of performing annular illumination. It is a flowchart which shows the adjustment method of the illumination optical system by one Embodiment of this invention. It is a figure which shows the 1st structural example of the illumination optical system which can apply the adjustment method of this invention. It is a figure which shows schematic structure of the exposure apparatus by one Embodiment of this invention. It is a flowchart which shows an example of the manufacturing process of a device. It is a figure which shows an example of the detailed flow of step S23 of FIG. 7 in the case of a semiconductor device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Light source 2 Movable mirror 4 Diffractive optical element 5 1st zoom optical system 6 Movable mirror 7 1st fly eye lens 8 3rd zoom optical system 8a Lens 9 Movable mirror 10 2nd fly eye lens 30 Fly eye lens 31 Diffractive optical element 40 Illumination optical system 41 Reticle stage 47 Wafer stage DP Device pattern IS Illumination optical system LP Irradiated surface LP3 Incident surface R Reticle W Wafer

Claims (14)

A method for adjusting an illumination optical system, comprising: a light source that supplies a light beam; and an optical integrator on which the light beam from the light source is incident, and guides the light beam from the optical integrator to an irradiated surface,
A correction step of correcting a collapse of telecentricity of a light beam incident on the irradiated surface or its conjugate surface by adjusting an optical member disposed on an optical path between the light source and the optical integrator. A method for adjusting the illumination optical system. The optical member includes a deflecting member that deflects a light beam from the light source,
2. The illumination optical system according to claim 1, wherein the correcting step corrects a collapse of telecentricity of a light beam incident on the irradiated surface or a conjugate surface thereof by adjusting a deflection angle of the deflecting member. Adjustment method. A variable magnification optical system is disposed between the optical integrator and the deflecting member,
The method for adjusting an illumination optical system according to claim 2, wherein a fly-eye lens or a diffractive optical element is disposed between the deflecting member and the variable power optical system.   The deflection member adjusts a deflection angle so that an incident position of a light beam with respect to the irradiated surface or a conjugate surface thereof does not change even when a zoom ratio of the zoom optical system is changed. Item 4. A method for adjusting an illumination optical system according to Item 3. The optical member includes a refractive member that refracts a light beam from the light source,
In the correcting step, the position of the refractive member in the direction intersecting the optical axis of the light beam is adjusted to correct the collapse of the telecentricity of the light beam incident on the irradiated surface or its conjugate surface. The method of adjusting an illumination optical system according to claim 1.   6. The method for adjusting an illumination optical system according to claim 5, wherein a fly-eye lens or a diffractive optical element is disposed on the light source side of the refractive member.   2. The correction step includes adjusting the optical member based on a detection result obtained by detecting an incident position of the light beam with respect to the irradiated surface or a conjugate surface thereof with a detection device. The adjustment method of the illumination optical system as described in any one of Claims 6. A variable magnification optical system is disposed between the optical member and the light source,
The adjustment of the illumination optical system according to any one of claims 1 to 7, wherein a fly-eye lens or a diffractive optical element is disposed between the light source and the zoom optical system. Method.   Another deflection member disposed between the light source and the fly-eye lens or diffractive optical element is also used to correct the collapse of the telecentricity of the light beam incident on the irradiated surface or its conjugate surface. The method for adjusting an illumination optical system according to claim 8.   The another deflecting member deflects so that the incident position of the light beam on the irradiated surface or its conjugate surface does not change even if the zooming ratio of the zooming optical system between the optical member and the light source is changed. The method for adjusting an illumination optical system according to claim 9, wherein the angle is adjusted. In the correction step, for each illumination condition set by the illumination condition setting means, an adjustment amount for obtaining an adjustment amount of the optical element capable of correcting the collapse of the telecentricity of the light beam incident on the irradiated surface or its conjugate surface A calculation process;
An adjustment step of adjusting the optical element based on the adjustment amount obtained in the adjustment amount calculation step according to the illumination condition set by the illumination condition setting means. Item 11. A method for adjusting an illumination optical system according to any one of Items 10 to 10. An exposure apparatus for transferring a pattern formed on a mask onto a substrate,
An illumination optical system adjusted by using the illumination optical system adjustment method according to any one of claims 1 to 11,
A mask stage for disposing the mask on the irradiated surface;
An exposure apparatus comprising: a substrate stage that holds the substrate.   13. A device manufacturing method using the exposure apparatus according to claim 12. An exposure method for transferring a pattern formed on a mask onto a substrate,
The illumination optical system adjusted using the illumination optical system adjustment method according to any one of claims 1 to 11, illuminates the mask, and a pattern formed on the mask is formed on the substrate. An exposure method characterized by transferring to a substrate.

Images