JP2006024763A - Evaluating method for exposure apparatus, exposure system, and manufacturing method for device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an evaluating method for exposure apparatuses whereby the more quantitative evaluations than conventional ones are made possible. <P>SOLUTION: The evaluating method for exposure apparatuses has a first process (S102) for memorizing the operational sequences required when performing the exposures of patterns to partitioned regions, a second process (S103) for operating a scanning type exposure apparatus while altering the settings of the operational parameters relative to exposure operations which are included in the abovementioned operational sequences, a third process (S104) for measuring by using the measuring devices provided in the scanning type exposure apparatus with the informations relative to a first characteristic of the scanning type exposure apparatus at the every alteration of the operational parameters, when operating the scanning type exposure apparatus in the second process; and a fourth process (S105) for performing the estimating computations (simulations) of the predetermined performances of the scanning type exposure apparatus, based on the plurality of informations relative to the first characteristic which have been measured in the third process. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an exposure apparatus evaluation method, an exposure system, and a device manufacturing method.

  Conventionally, in a manufacturing process of an electronic device such as a semiconductor element or a liquid crystal display element, a circuit pattern formed on a mask (or reticle) is applied to a substrate (wafer or photo resist) coated with a resist (photosensitive agent) via a projection optical system. An exposure apparatus that transfers onto a glass plate or the like is used. As an exposure apparatus, for example, a step-and-scan type scanning exposure apparatus (so-called scanning stepper) that transfers a mask pattern to each shot area on the substrate by synchronously moving the mask and the substrate in a one-dimensional direction. There is.

As an evaluation method for an exposure apparatus, a method is used in which the line width of a pattern transferred onto a photosensitive substrate is measured with a scanning electron microscope (SEM) or the like, and the imaging performance of the projection optical system is calculated based on the measurement result. Is generally known.
In addition to this, there is a method for evaluating an exposure apparatus by actually illuminating a measurement mask with illumination light and measuring a spatial image (projected image) of a measurement pattern formed by a projection optical system without actually performing exposure. Yes (see Patent Document 1). This method has an advantage that the processing time is shortened as compared with the actual measurement method using SEM or the like.
Japanese Patent Laid-Open No. 10-209031

  In recent years, integrated circuits have been integrated at a high density, that is, circuit patterns have been miniaturized, and accordingly, further improvements in performance, yield, throughput, and the like are desired for exposure apparatuses. In particular, in order to improve performance, a more quantitative exposure apparatus evaluation method is desired.

The present invention has been made in view of the above-described circumstances, and an object thereof is to provide an exposure apparatus evaluation method capable of more quantitative evaluation.
Another object of the present invention is to provide a device manufacturing method capable of manufacturing a high-quality device.
Another object of the present invention is to provide an exposure system capable of improving exposure accuracy.

The present invention includes a mask stage (RST) on which a mask (R) is placed and moved in a two-dimensional plane, and a substrate stage (WST) on which a substrate (W) is placed and moved in a two-dimensional plane. A scanning exposure apparatus that sequentially irradiates the pattern on the mask onto a plurality of partitioned areas on the substrate by illuminating the mask with an exposure beam while moving both the stages (RST, WST) synchronously. An exposure apparatus evaluation method for evaluating performance, wherein a first step of storing an operation sequence at the time of performing exposure of the pattern on a predetermined partition region on the substrate, and the exposure of the operation sequence. A second step of operating the scanning exposure apparatus while changing the setting of operation parameters relating to the operation, and the scanning exposure when operating the scanning exposure apparatus in the second step. A third step of measuring information on the first characteristic of the device each time the operating parameter is changed using a measuring device (54W, 54R, 60a, 60b, 46) provided in the scanning exposure apparatus And a fourth step of estimating (simulating) the predetermined performance of the scanning exposure apparatus based on information on the plurality of first characteristics measured in the third step. .
In the above evaluation method, the operating parameters include, for example, the synchronous movement speed of the two stages, the length that the exposure beam is scanned on the substrate when exposing the partitioned area, and the plurality of partitioned areas. At least one of the positions on the two-dimensional plane.

  According to this evaluation method, the characteristics of the exposure apparatus are measured while changing the setting of the operation parameter, and the predetermined performance of the exposure apparatus is estimated and calculated based on the measurement result, thereby further quantifying the predetermined performance of the exposure apparatus. Evaluation is possible.

  The present invention also provides a mask stage (RST) on which a mask (R) is placed and moved in a two-dimensional plane, and a substrate stage (WST) on which a substrate (W) is placed and moved in a two-dimensional plane. A scanning exposure apparatus that sequentially irradiates the pattern on the mask onto a plurality of partitioned regions on the substrate by illuminating the mask with an exposure beam while moving both the stages (RST, WST) synchronously. An exposure apparatus evaluation method for evaluating a predetermined performance of a first step of storing an operation sequence when performing exposure of the pattern on a plurality of partitioned regions on the substrate, and based on the operation sequence A second step of operating the scanning exposure apparatus, and a first characteristic of the scanning exposure apparatus when the scanning exposure apparatus is operated for the plurality of partitioned areas in the second step. A third step of measuring information for each of the plurality of partitioned regions using a measuring device (54W, 54R, 60a, 60b, 46) provided in the scanning exposure apparatus; and the third step And a fourth step of estimating and calculating (simulating) the predetermined performance of the scanning exposure apparatus based on information on the plurality of first characteristics measured for each of the plurality of partitioned regions.

  According to this evaluation method, the characteristics of the exposure apparatus are measured for each of a plurality of divided regions, and the predetermined performance of the exposure apparatus is estimated and calculated based on the measurement result, whereby the predetermined performance of the exposure apparatus is more quantitatively determined. Evaluation is possible.

  In each of the above evaluation methods, the predetermined performance is, for example, at least one of the uniformity of the line width of the pattern image transferred onto the substrate by the exposure operation of the scanning exposure measure and the contrast of the pattern image. including.

  Further, in each of the evaluation methods, the operation sequence includes a movement sequence of the mask stage and the substrate stage in the two-dimensional plane. In the second step, both stages are performed based on the movement sequence. The measurement apparatus includes a first interferometer (54R) that measures position information of the mask stage and a second interferometer (54W) that measures position information of the substrate stage, and the third step Then, the information regarding the synchronization accuracy between the two stages as the first characteristic may be measured based on the output from the first interferometer and the output from the second interferometer.

  In each of the evaluation methods, the operation sequence includes a focus / leveling movement sequence of the substrate stage in a direction orthogonal to the two-dimensional plane. In the second step, the operation sequence is based on the focus / leveling movement sequence. The substrate stage is moved, and the measuring device includes focus leveling sensors (60a, 60b) for measuring information on the position of the substrate placed on the substrate stage in the orthogonal direction and the inclination with respect to the orthogonal direction. In the third step, information on the followability of the substrate stage with respect to a target focus / leveling position as the first characteristic may be measured based on an output from the focus / leveling sensor.

  In each evaluation method, the operation sequence includes an exposure energy amount setting sequence for exposing the substrate. In the second step, exposure to the plurality of partitioned regions is performed based on the setting sequence. An energy amount is set, and the measurement apparatus includes a photoelectric sensor (46) for measuring an actual exposure energy amount of an exposure beam emitted with the target exposure energy amount set in the second step, and the third sensor In the step, information regarding an error in an actual exposure energy amount with respect to the target exposure energy amount as the first characteristic may be measured based on an output from the photoelectric sensor.

Each of the evaluation methods further includes a fifth step of measuring in advance information relating to the second characteristic of the scanning exposure apparatus before performing the second step, and in the fourth step, More preferably, the predetermined performance is estimated by executing the estimation calculation using the information on the first characteristic obtained in the third step and the information on the second characteristic obtained in the fifth step. .
Here, the second characteristic includes, for example, energy uniformity of the exposure beam in an irradiation region where the exposure beam for exposing the substrate is irradiated onto the substrate.
The second characteristic includes, for example, an imaging characteristic of a projection optical system (PL) that projects a pattern on the mask onto the substrate.

  Each of the evaluation methods may further include a sixth step of inputting at least one of information related to a photosensitive material coating process on the substrate and information related to a developing process on the substrate, In the step, the estimation using the information on the first characteristic obtained in the third step, the information on the second characteristic obtained in the fifth step, and the information obtained in the sixth step More preferably, the predetermined performance is estimated by performing an operation.

  Further, the present invention is a device manufacturing method, the step of optimizing exposure conditions set in the scanning exposure apparatus so that the predetermined performance is the best based on the evaluation result by the evaluation method, And transferring the device pattern formed on the mask onto the substrate using the optimized exposure apparatus.

  The present invention also provides a mask stage (RST) on which a mask (R) is placed and moved in a two-dimensional plane, and a substrate stage (WST) on which a substrate (W) is placed and moved in a two-dimensional plane. A scanning exposure apparatus that sequentially irradiates the pattern on the mask onto a plurality of partitioned regions on the substrate by illuminating the mask with an exposure beam while moving both the stages (RST, WST) synchronously. An exposure system for estimating a predetermined performance of the storage device (11C) for storing an operation sequence for performing exposure of the pattern on a predetermined partition region on the substrate; A control device (50) for operating the scanning exposure apparatus while changing the setting of operation parameters relating to the exposure operation; and the scanning exposure apparatus is operating under the control of the control device. Sometimes, each time the operating parameter is changed, a measuring device (54W, 54R, 60a, 60b, 46) that measures information about the first characteristic of the scanning exposure apparatus, and a plurality of measurements measured by the measuring device And an arithmetic unit (11) for estimating and calculating the predetermined performance of the scanning exposure apparatus based on the information on the first characteristic.

  The present invention also provides a mask stage (RST) on which a mask (R) is placed and moved in a two-dimensional plane, and a substrate stage (WST) on which a substrate (W) is placed and moved in a two-dimensional plane. A scanning exposure apparatus that sequentially irradiates the pattern on the mask onto a plurality of partitioned regions on the substrate by illuminating the mask with an exposure beam while moving both the stages (RST, WST) synchronously. An exposure system that estimates a predetermined performance of the storage device (11C) that stores an operation sequence when the pattern is exposed to a plurality of partitioned areas on the substrate, and the storage device (11C) based on the operation sequence Information on the first characteristic of the scanning exposure apparatus when the scanning exposure apparatus is operated under the control of the control apparatus (50) for operating the scanning exposure apparatus and the control apparatus Based on the measurement device (54W, 54R, 60a, 60b, 46) for measuring each of the plurality of partitioned areas, and information on the plurality of first characteristics measured for each of the plurality of partitioned areas by the measuring device, And an arithmetic unit (11) for estimating and calculating the predetermined performance of the scanning exposure apparatus.

According to the exposure apparatus evaluation method of the present invention, it is possible to more accurately evaluate the predetermined performance of the exposure apparatus by quantitative evaluation.
In addition, according to the device manufacturing method of the present invention, the performance of the exposure apparatus is more quantitatively evaluated, so that a high-quality device can be manufactured based on this.
Further, according to the exposure system of the present invention, the predetermined performance of the exposure apparatus is more quantitatively evaluated, so that the exposure accuracy can be improved based on the predetermined performance.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 schematically shows a configuration of an exposure system 100 including a reduction projection type projection exposure apparatus 10 for manufacturing a semiconductor device and a management apparatus 11 for managing the same. The exposure apparatus 10 of this example uses a step-and-scan method (by moving the mask and the photosensitive substrate synchronously in opposite directions while projecting a slit-like pattern, by forming a pattern formed on the reticle R as a mask. This is a scanning exposure apparatus (scanning stepper) that projects a mask pattern onto a shot area (partition area) of a wafer W as a photosensitive substrate through a projection optical system PL).

  The exposure apparatus 10 freely moves in an XY plane while holding an illumination system including a light source 14 and an illumination optical system 12, a reticle stage RST that holds a reticle R as a mask, a projection optical system PL, and a wafer W as a substrate. A wafer stage WST as a possible substrate stage and a control system for controlling these are provided. Although not shown in the drawings, the components other than the light source and the control system in the above components are actually environments (not shown) in which environmental conditions such as internal temperature and pressure are maintained with high accuracy. It is housed in a control chamber (environmental chamber).

  Here, as the light source 14, for example, an excimer laser light source that outputs KrF excimer laser light (wavelength 248 nm) or ArF excimer laser light (wavelength 193 nm) is used. This light source 14 is actually installed in a service room or the like having a low degree of cleanness other than the clean room in which the environment control chamber is installed, and illumination light inside the environment control chamber is transmitted via a light transmission optical system (not shown). It is connected to the system 12. The light source 14 is controlled to turn on / off the laser emission, the center wavelength, the spectral half width, the repetition frequency, and the like by a main controller 50 including a workstation (or a microcomputer).

  The illumination optical system 12 includes a beam shaping optical system 18, a fly-eye lens 22 as an optical integrator (homogenizer), an illumination system aperture stop plate 24, relay optical systems 28A and 28B, a fixed reticle blind 30A, a movable reticle blind 30B, a mirror. M, a condenser lens 32, and the like. Note that a rod-type (internal reflection type) integrator or the like may be used as the optical integrator.

  In the beam shaping optical system 18, in order to shape the cross-sectional shape of the laser beam LB pulsed by the light source 14 so as to efficiently enter the fly-eye lens 22 provided behind the optical path of the laser beam LB. For example, a cylinder lens and a beam expander (both not shown) are included.

  The fly-eye lens 22 is disposed on the optical path of the laser beam LB emitted from the beam shaping optical system 18, and is a surface light source composed of a number of point light sources (light source images) for illuminating the reticle R with a uniform illuminance distribution. That is, a secondary light source is formed. In this specification, the laser beam emitted from the secondary light source is also referred to as “illumination light IL”.

  An illumination system aperture stop plate 24 made of a disk-shaped member is disposed in the vicinity of the exit-side focal plane of the fly-eye lens 22. In this illumination system aperture stop plate 24, an aperture stop made of, for example, a normal circular aperture, an aperture stop for annular illumination, an aperture stop for a modified light source method, and the like are arranged at equal angular intervals. The illumination system aperture stop plate 24 is rotated by a drive device 40 such as a motor controlled by the main control device 50, whereby any aperture stop is selectively placed on the optical path of the illumination light IL. Set to

  A beam splitter 26 having a low reflectance and a high transmittance is disposed on the optical path of the illumination light IL emitted from the illumination system aperture stop plate 24, and further, relays are provided on the rear optical path with reticle blinds 30A and 30B interposed therebetween. Optical systems (28A, 28B) are arranged.

  The fixed reticle blind 30A is disposed on a surface slightly defocused from the conjugate surface with respect to the pattern surface of the reticle R, and a rectangular opening that defines the illumination area IAR on the reticle R is formed. Further, a movable reticle blind 30B having an opening having a variable position and width in the direction corresponding to the scanning direction (X-axis direction here) and the non-scanning direction (Y-axis direction) in the vicinity of the fixed reticle blind 30A. Is arranged, and the exposure area IAR is further restricted via the movable reticle blind 30B at the start and end of the scanning exposure, thereby preventing unnecessary exposure. In the present embodiment, the movable reticle blind 30 </ b> B is also used for setting an illumination area in a later-described aerial image measurement.

  On the other hand, on the optical path of the illumination light IL reflected by the beam splitter 26 in the illumination optical system 12, the condenser lens 44 and the sensitivity in the far ultraviolet region are high, and it is high in order to detect the pulse emission of the light source 14. An integrator sensor 46 composed of a light receiving element such as a PIN photodiode having a response frequency is disposed.

  The operation of the illumination system configured in this way will be briefly described. The laser beam pulsed from the light source 14 enters the beam shaping optical system 18 and efficiently enters the rear fly-eye lens 22 here. After the cross-sectional shape is shaped as described above, the light enters the fly-eye lens 22. Thereby, a secondary light source is formed on the exit-side focal plane of the fly-eye lens 22 (the pupil plane of the illumination optical system 12). The illumination light IL emitted from the secondary light source passes through one of the aperture stops on the illumination system aperture stop plate 24 and then reaches the beam splitter 26 having a high transmittance and a low reflectivity. The illumination light IL transmitted through the beam splitter 26 passes through the first relay lens 28A, passes through the rectangular opening of the fixed reticle blind 30A and the movable reticle blind 30B, passes through the second relay lens 28B, and is reflected by the mirror M. After the optical path is bent vertically downward, the illumination area IAR on the reticle R held on the reticle stage RST is illuminated with a uniform illuminance distribution through the condenser lens 32.

  On the other hand, the illumination light IL reflected by the beam splitter 26 is received by the integrator sensor 46 via the condenser lens 44, and the photoelectric conversion signal of the integrator sensor 46 passes through a peak hold circuit and an A / D converter (not shown). It is supplied to the main controller 50 through the signal processing device 80 having the same.

  On reticle stage RST, reticle R is fixed by, for example, vacuum suction (or electrostatic suction). Here, the reticle stage RST is two-dimensionally (in the X-axis direction and orthogonal to the X-axis direction) in an XY plane perpendicular to the optical axis AX of the projection optical system PL described later by a reticle stage drive system 56R including a linear motor or the like. It can be finely driven in the Y-axis direction and the rotation direction (θz direction) about the Z-axis orthogonal to the XY plane, and can move on the reticle base RBS at a scanning speed specified in the Y-axis direction. The reticle stage RST has a movement stroke in the Y-axis direction that allows the entire surface of the reticle R to cross at least the optical axis AX of the projection optical system PL.

  A movable mirror 52R that reflects a laser beam from a reticle laser interferometer (hereinafter referred to as a “reticle stage interferometer”) 54R is fixed on the reticle stage RST. The position of the reticle stage RST in the XY plane is fixed to the reticle stage RST. The stage interferometer 54R always detects with a resolution of about 0.5 to 1 nm, for example. Here, actually, on the reticle stage RST, a moving mirror having a reflecting surface orthogonal to the scanning direction (Y-axis direction) at the time of scanning exposure and a movement having a reflecting surface orthogonal to the non-scanning direction (X-axis direction). The reticle stage interferometer 54R is provided with at least two axes in the Y-axis direction and at least one axis in the X-axis direction. In FIG. 1, these are typically the movable mirror 52R and the reticle stage interferometer 54R. Is shown as

  Position information of reticle stage RST from reticle stage interferometer 54R is sent to stage controller 70 as a table control system and main controller 50 via this. The stage control device 70 controls the movement of the reticle stage RST via the reticle stage drive system 56R in accordance with an instruction from the main control device 50.

  The projection optical system PL is disposed below the reticle stage RST in FIG. 1, and the direction of the optical axis AX is the Z-axis direction. Here, the projection optical system PL is a double-sided telecentric reduction system, and is predetermined along the optical axis AX direction. A refractive optical system comprising a plurality of lens elements arranged at intervals is used. The projection magnification of the projection optical system PL is, for example, 1/4 or 1/5. For this reason, when the slit illumination area IAR on the reticle R is illuminated by the illumination light IL from the illumination optical system 12, the slit illumination is passed through the projection optical system PL by the illumination light IL that has passed through the reticle R. A reduced image (partial inverted image) of the circuit pattern of the reticle R in the area IAR is formed in an exposure area IA conjugate with the illumination area IAR on the wafer W whose surface is coated with a photoresist.

  Among the plurality of lens elements constituting the projection optical system PL, some of the plurality of lens elements are minutely driven by a drive element (not shown) (for example, a piezo element) in the optical axis AX direction and the tilt direction with respect to the XY plane. It is configured to be possible. The drive voltage of each drive element (drive amount of the drive element) is controlled by the imaging characteristic correction controller 78 in accordance with a command from the main controller 50, and thereby the imaging characteristic of the projection optical system PL, for example, the image plane Curves, distortion, magnification, etc. are corrected. That is, in the present embodiment, an imaging characteristic correction device is configured by the driving element that drives the above-described drivable lens element and the imaging characteristic correction controller 78 that controls the driving amount.

  Wafer stage WST includes XY stage 42 and Z tilt stage 38 as a substrate table mounted on XY stage 42.

  The XY stage 42 is levitated and supported above the upper surface of the wafer base 16 by an air bearing (not shown) through a clearance of about several μm, for example, and is scanned in the scanning direction by a linear motor (not shown) constituting the wafer stage drive system 56W. Are configured to be capable of two-dimensional drive in the Y-axis direction (left-right direction in the drawing in FIG. 1) and the X-axis direction (direction orthogonal to the drawing in FIG. 1) perpendicular thereto. A Z tilt stage 38 is mounted on the XY stage 42, and the wafer holder 25 is mounted on the Z tilt stage 38. The wafer W is held by the wafer holder 25 by vacuum suction or the like.

  As shown in FIG. 2, the Z tilt stage 38 has three points on the XY stage 42 by three Z position driving units 27A, 27B, and 27C (however, the Z position driving unit 27C on the back side of the paper is not shown). It is supported. These Z position driving units 27A to 27C have three actuators (for example, a voice coil motor) that independently drive the respective support points on the lower surface of the Z tilt stage 38 in the optical axis direction (Z direction) of the projection optical system PL. 21A, 21B, 21C (however, the actuator 21C at the back of the paper surface in FIG. 2 is not shown), and Z by the actuators 21A, 21B, 21C at the respective support points by the Z position driving units 27A, 27B, 27C of the Z tilt stage It includes encoders 23A to 23C (however, the encoder 23C on the back side in FIG. 2 is not shown) as sensors for detecting an axial driving amount (displacement from the reference position). Here, as the encoders 23 </ b> A to 23 </ b> C, for example, optical or electrostatic linear encoders are used. In the present embodiment, the actuator 21A, 21B, 21C causes the Z tilt stage 38 to be tilted with respect to the optical axis AX direction (Z-axis direction) and the plane (XY plane) orthogonal to the optical axis, that is, the rotational direction around the X axis. The driving device is configured to drive in the θx direction that is and the θy direction that is the rotation direction around the Y axis. Further, the driving amount (displacement amount from the reference point) of each supporting point by the Z position driving units 27A, 27B, and 27C of the Z tilt stage 38 measured by the encoders 23A to 23C is determined by the stage controller 70 and This is supplied to the main controller 50, and the main controller 50 calculates the position and leveling amount (θx rotation amount, θy rotation amount) of the Z tilt stage 38 in the Z-axis direction. In FIG. 1, a linear motor or the like that drives the XY stage 42 and Z position driving units 27A to 27C (actuators 21A to 21C and encoders 23A to 23C) are shown as a wafer stage driving system 56W.

  The wafer holder 25 is placed on the Z tilt stage 38, and the wafer W is held by the wafer holder 25 by vacuum suction (or electrostatic suction).

  On the Z tilt stage 38, a movable mirror 52W that reflects a laser beam from a wafer laser interferometer (hereinafter referred to as “wafer stage interferometer”) 54W is fixed. The position in the XY plane of the Z tilt stage 38 (wafer stage WST) is always detected with a resolution of about 0.5 to 1 nm, for example.

  Here, actually, on the Z tilt stage 38, a movable mirror having a reflecting surface orthogonal to the Y-axis direction that is the scanning direction at the time of scanning exposure and a reflecting surface orthogonal to the X-axis direction that is the non-scanning direction are provided. Corresponding to this, a plurality of wafer stage interferometers are also provided in the X-axis direction and Y-axis direction, respectively, and the four-degree-of-freedom direction of the Z tilt stage 38 (X-axis direction, Y-axis direction, The positions in the [theta] x direction and [theta] y direction) can be measured, but in FIG. 1, these are typically shown as a movable mirror 52W and a wafer stage interferometer 54W. Position information (or speed information) of wafer stage WST is supplied to stage controller 70 and main controller 50 via this. Stage controller 70 controls the position of wafer stage WST in the XY plane via wafer stage drive system 56W in accordance with an instruction from main controller 50.

  Further, inside the Z tilt stage 38, a part of the optical system constituting the aerial image measuring device 59 used for measuring the optical characteristics of the projection optical system PL is arranged.

  Here, the configuration of the aerial image measurement device 59 will be described in detail. As shown in FIG. 3, the aerial image measuring device 59 includes a stage-side component provided on the Z tilt stage 38, that is, a slit plate 90 as a pattern forming member, a relay optical system including lenses 84 and 86, an optical path, and the like. A bending mirror 88, a light transmission lens 87, and a component outside the stage provided outside the wafer stage WST, that is, a mirror 96, a light receiving lens 89, an optical sensor 95 as a photoelectric conversion element, and the like are provided.

  More specifically, as shown in FIG. 3, the slit plate 90 is viewed from above in a state where the opening is closed against the protruding portion 58 provided on the upper surface of one end of the wafer stage WST. It is inserted. In this slit plate 90, a reflection film 83 also serving as a light shielding film is formed on the upper surface of a light receiving glass 82 having a rectangular shape in plan view, and a slit-shaped opening pattern (a predetermined width 2D) as a measurement pattern is formed on a part of the reflection film 83. (Hereinafter referred to as “slit”) 94 is formed by patterning.

  As the material of the light receiving glass 82, here, KrF excimer laser light, synthetic quartz, fluorite, or the like having good transparency of ArF excimer laser light is used.

  In the Z tilt stage 38 below the slit 94, a relay optical system (comprising lenses 84, 86) is interposed via a mirror 88 that horizontally folds the optical path of an illumination light beam (image light beam) incident vertically downward through the slit 94. 84, 86), and the illumination light beam relayed by the relay optical system (84, 86) for a predetermined optical path length on the side wall on the + Y side of wafer stage WST behind the optical path of this relay optical system (84, 86). A light transmission lens 87 for transmitting the light to the outside of wafer stage WST is fixed.

  A mirror 96 having a predetermined length in the X-axis direction is provided obliquely at an inclination angle of 45 ° on the optical path of the illumination light beam sent out of wafer stage WST by light transmission lens 87. By this mirror 96, the optical path of the illumination light beam sent to the outside of wafer stage WST is bent 90 ° vertically upward. A light receiving lens 89 having a diameter larger than that of the light transmitting lens 87 is disposed on the bent optical path. An optical sensor 95 is disposed above the light receiving lens 89. The light receiving lens 89 and the optical sensor 95 are housed in a case 92 while maintaining a predetermined positional relationship, and the case 92 is located near the upper end portion of a support column 97 that is implanted on the upper surface of the base 16 via an attachment member 93. It is fixed.

  As the optical sensor 95, a photoelectric conversion element (light receiving element) capable of accurately detecting weak light, for example, a photomultiplier tube (PMT, photomultiplier tube) or the like is used. The photoelectric conversion signal P from the optical sensor 95 is sent to the main control device 50 via the signal processing device 80 of FIG. The signal processing device 80 can be configured to include, for example, an amplifier, a sample holder, an A / D converter (usually having a resolution of 16 bits).

  Although the slit 94 is formed in the reflective film 83 as described above, the following description will be made assuming that the slit 94 is formed in the slit plate 90 for convenience.

  According to the aerial image measurement device 59 configured as described above, projection optics is used when measuring a projection image (aerial image) of a measurement mark formed on the reticle R through the projection optical system PL, which will be described later. When the slit plate 90 constituting the aerial image measuring device 59 is illuminated by the illumination light IL transmitted through the system PL, the illumination light IL transmitted through the slit 94 on the slit plate 90 is converted into the lens 84, the mirror 88, and the lens 86. Then, it is led out of wafer stage WST via light transmission lens 87. Then, the light guided to the outside of the wafer stage WST is bent vertically upward by the mirror 96 and received by the optical sensor 95 through the light receiving lens 89, and the light received from the optical sensor 95 according to the amount of light received. A photoelectric conversion signal (light quantity signal) P is output to the main control device 50 via the signal processing device 80.

  In the case of this embodiment, the measurement of the projected image (aerial image) of the measurement mark is performed by the slit scan method, and in this case, the light transmitting lens 87 moves relative to the light receiving lens 89 and the optical sensor 95. become. Therefore, in the aerial image measuring device 59, the size of each lens and the mirror 96 is set so that all the light passing through the light transmitting lens 87 that moves within a predetermined range is incident on the light receiving lens 89.

  As described above, in the aerial image measurement device 59, the slit plate 90, the lenses 84 and 86, the mirror 88, and the light transmission lens 87 constitute a light derivation unit that derives light through the slit 94 to the outside of the wafer stage WST. The light receiving lens 89 and the optical sensor 95 constitute a light receiving unit that receives light led out of the wafer stage WST. In this case, the light derivation unit and the light receiving unit are mechanically separated. Then, only when the aerial image is measured, the light derivation unit and the light receiving unit are optically connected via the mirror 96.

  That is, in the aerial image measurement device 59, since the optical sensor 95 is provided at a predetermined position outside the wafer stage WST, the measurement accuracy of the wafer stage interferometer 54W caused by the heat generation of the optical sensor 95 can be adversely affected. I try to suppress it in range. Further, since the outside and inside of wafer stage WST are not connected by a light guide or the like, the driving accuracy of wafer stage WST is adversely affected as in the case where the outside and inside of wafer stage WST are connected by a light guide. There is nothing.

  Of course, when the influence of heat or the like can be ignored or eliminated, the optical sensor 95 may be provided inside the wafer stage WST. An aerial image measurement method and an optical property measurement method performed using the aerial image measurement device 59 will be described in detail later.

  Returning to FIG. 1, an off-axis alignment system ALG as a mark detection system for detecting an alignment mark (positioning mark) on the wafer W is provided on the side surface of the projection optical system PL. In this embodiment, as this alignment system ALG, an image processing type alignment sensor, a so-called FIA (Field Image Alignment) system is used. The detection signal of the alignment system ALG is supplied to the main controller 50.

  Further, as shown in FIG. 1, the exposure apparatus 10 of the present embodiment has a light source whose on / off is controlled by the main controller 50, and has a large number of pinholes or holes toward the image plane of the projection optical system PL. From an irradiation system 60 a that irradiates an image forming light beam for forming an image of the slit from an oblique direction with respect to the optical axis AX, and a light receiving system 60 b that receives a reflected light beam on the surface of the wafer W of the image forming light beam. An oblique incident light type multi-point focal position detection system is provided. The detailed configuration of the multipoint focal position detection system similar to the focal position detection system (60a, 60b) of the present embodiment is disclosed in, for example, Japanese Patent Laid-Open No. 6-283403.

  The main controller 50 sets the wafer stage drive system 56W so that the focus shift becomes zero based on a defocus signal (defocus signal) from the light receiving system 60b, for example, an S curve signal, at the time of scanning exposure described later. The Z tilt stage 38 is moved in the Z-axis direction and the tilt (that is, the rotation in the θx and θy directions) is controlled two-dimensionally, that is, the multipoint focal position detection system (60a, 60b) is used to perform Z By controlling the movement of the tilt stage 38, autofocusing that substantially matches the imaging surface of the projection optical system PL and the surface of the wafer W within the irradiation region of the illumination light IL (image formation relationship with the illumination region IAR). (Auto focus) and auto leveling (focus leveling) are executed.

  An environmental sensor 81 for detecting atmospheric pressure fluctuations and temperature fluctuations is provided in the vicinity of the projection optical system PL in the environmental control chamber (not shown). The measurement result by the environment sensor 81 is supplied to the main controller 50.

  Next, the operation of the exposure process in the exposure apparatus 10 of the present embodiment configured as described above will be briefly described.

  First, reticle R is transported by a reticle transport system (not shown), and is sucked and held on reticle stage RST at the loading position. Next, under the instruction of the main controller 50, the positions of the wafer stage WST and the reticle stage RST are controlled by the stage controller 70, and the main controller 50 projects a reticle alignment mark (not shown) formed on the reticle R. An image (aerial image) is measured using the aerial image measuring device 59 as described later, and the projection position of the reticle pattern image is obtained. That is, reticle alignment is performed.

  Next, in accordance with an instruction from main controller 50, stage controller 70 moves wafer stage WST so that slit plate 90 constituting aerial image measuring device 59 is positioned directly below alignment system ALG, and alignment is performed. A slit 94 serving as a position reference for the aerial image measurement device 59 is detected by the system ALG. In main controller 50, based on the detection signal of alignment system ALG, the measurement value of wafer stage interferometer 54W at that time, and the projection position of reticle pattern image obtained earlier, the projection position of pattern image of reticle R A relative position with respect to the alignment system ALG, that is, a baseline amount of the alignment system ALG is obtained.

  When such baseline measurement is completed, the main controller 50 performs wafer alignment such as EGA (Enhanced Global Alignment), which is disclosed in detail in, for example, Japanese Patent Laid-Open No. 61-44429 and the like on the wafer W. The positions of all shot areas are obtained. In this wafer alignment, a wafer alignment mark of a predetermined sample shot out of a plurality of shot areas on the wafer W is measured using the alignment system ALG.

  Next, main controller 50 monitors position information sent from laser interferometers 54W and 54R via stage controller 70 based on the position information and baseline amount of each shot area on wafer W obtained above. At the same time, the stage controller 70 is instructed. Then, stage control device 70 positions wafer stage WST at the scanning start position of the first shot area, positions reticle stage RST at the scanning start position, and both stages RST for exposure of the first shot area. , WST starts moving (scanning).

  In stage controller 70, when both stages RST and WST reach their target scanning speeds, the pattern area of reticle R begins to be illuminated by illumination light IL, and scanning exposure is started.

  In the stage controller 70, the moving speed Vr of the reticle stage RST in the Y-axis direction and the moving speed Vw of the wafer stage WST in the X-axis direction have a speed ratio corresponding to the projection magnification of the projection optical system PL, particularly during the above-described scanning exposure. The reticle stage RST and wafer stage WST are synchronously controlled so as to be maintained.

  Then, different areas of the pattern area of the reticle R are sequentially illuminated with ultraviolet pulse light, and the illumination of the entire pattern area is completed, whereby the scanning exposure of the first shot area on the wafer W is completed. Thereby, the circuit pattern of the reticle R is reduced and transferred to the first shot area via the projection optical system PL.

  When the scanning exposure of the first shot area is thus completed, under the instruction of the main controller 50, the stage controller 70 performs a stepping operation between shots to move the wafer stage WST to the scanning start position of the second shot area. Then, scanning exposure of the second shot area is performed in the same manner as described above. Thereafter, the same operation is performed after the third shot area.

  In this manner, the stepping operation between shots and the scanning exposure operation of shots are repeated, and the pattern of the reticle R is transferred to all shot regions on the wafer W by the step-and-scan method.

Next, aerial image measurement using the aerial image measurement device 59 will be described.
FIG. 3 shows a state in which the aerial image of the measurement mark PMy formed on the reticle R is being measured using the aerial image measurement device 59. As the reticle R, a dedicated one for aerial image measurement or a device reticle used for manufacturing a device with a dedicated measurement mark is used. Instead of these reticles, a fixed mark plate (also called reticle fiducial mark plate) made of the same glass material as the reticle is provided on the reticle stage RST, and a measurement mark (measurement mark) is formed on this mark plate. You may use what you did.

  The reticle R is composed of a line-and-space (L / S) mark in which a ratio (duty ratio) of the width of the line portion and the width of the space portion having a periodicity in the Y-axis direction is 1: 1 at a predetermined location. It is assumed that the measurement mark PMy and the measurement mark PMx composed of L / S marks having a periodicity ratio of 1: 1 in the X-axis direction are formed close to each other. These measurement marks PMy and PMx are composed of line patterns having the same line width. Further, as shown in FIG. 4A, the slit plate 90 constituting the aerial image measuring device 59 includes a slit 94y having a predetermined width 2D extending in the Y-axis direction and a slit having a predetermined width 2D extending in the X-axis direction. 94x is formed in a positional relationship as shown in the figure.

  For example, in measuring the aerial image of the measurement mark PMy, the main reticle 50 drives the movable reticle blind 30B shown in FIG. 1 via a blind drive device (not shown), and the illumination area of the illumination light IL is changed to the measurement mark PM. It is limited to a predetermined area including the portion (see FIG. 3). In this state, when light emission of the light source 14 is started by the main controller 50 and the illumination light IL is irradiated onto the measurement mark PMy, the light diffracted and scattered by the measurement mark PMy (illumination light IL) is caused by the projection optical system PL. Refracted and a spatial image (projected image) of the measurement mark PMy is formed on the image plane of the projection optical system PL. At this time, as shown in FIG. 4A, wafer stage WST is at a position where a spatial image PMy ′ of measurement mark PMy is formed on the + Y side (or −Y side) of slit 94y on slit plate 90. It is assumed that it is set.

  Under the instruction of main controller 50, when stage controller 70 drives wafer stage WST in the + Y direction as indicated by arrow Fy in FIG. 4A, slit 94y is aerial image PMy ′. Are scanned in the Y-axis direction. During this scanning, light (illumination light IL) passing through the slit 94y is received by the optical sensor 95 via the light receiving optical system in the wafer stage WST, the reflection mirror 96 outside the wafer stage WST, and the light receiving lens 89, and the photoelectric The converted signal P is supplied to the signal processing device 80 shown in FIG. In the signal processing device 80, the photoelectric conversion signal is subjected to predetermined processing, and a light intensity signal corresponding to the aerial image PMy ′ is supplied to the main control device 50. At this time, the signal processing device 80 normalizes the signal from the optical sensor 95 with the signal from the integrator sensor 46 shown in FIG. 1 in order to suppress the influence of the variation in the emission intensity of the illumination light IL from the light source 14. The received signal is supplied to the main controller 50.

  FIG. 4B shows an example of a photoelectric conversion signal (light intensity signal) P obtained at the time of the aerial image measurement.

  When measuring the aerial image of the measurement mark PMx, the wafer stage WST is set to a position where the aerial image of the measurement mark PMx is formed on the + X side (or −X side) of the slit 94x on the slit plate 90. The photoelectric conversion signal (light intensity signal) corresponding to the aerial image of the measurement mark PMx can be obtained by performing measurement by the slit scan method similar to the above.

  Now, in actual exposure processing using the exposure apparatus 10, evaluation of predetermined performance of the exposure apparatus 10 is appropriately performed in order to optimize exposure conditions set in the exposure apparatus 10. This evaluation is performed mainly under the management of the management apparatus 11 prior to the exposure process or by temporarily suspending the exposure process. The management device 11 includes an input device 11A for inputting and outputting information, storage devices 11B and 11C for storing predetermined information, an arithmetic circuit (not shown), and the like.

  Hereinafter, as a method for evaluating the exposure apparatus 10, a method for evaluating the uniformity of the line width of a pattern image transferred onto the wafer W by the exposure apparatus 10 will be described with reference to the flowchart of FIG. This will be described in detail with reference to FIG.

(Input process information)
First, prior to the evaluation, information (process data) relating to the processing process is input to the management apparatus 11 (step 100). As process information, information (for example, resist material coefficient (fixed value for each resist)) on the wafer W used in the exposure apparatus 10, information on development processing after exposure (for example, developer material) Coefficient (fixed value for each developing solution), processing temperature, etc.) and parameters related to other processing processes. The process information is input via the input device 11A (for example, a keyboard, a communication device, etc.) by supplying information from an operator or a higher-level management device that comprehensively manages the entire processing line.

(Measurement of prior information)
Next, of the characteristics of the exposure apparatus 10, the optical characteristics of the exposure apparatus 10 are measured, and the measurement results are stored in the storage device 11B provided in the management apparatus 11 (step 101). Specifically, the energy uniformity (illuminance uniformity) of the illumination light IL (exposure beam) in the exposure area IA (irradiation area), and the imaging performance of the projection optical system PL (for example, field curvature, surface inclination, Measurement of imaging characteristics in the Z direction such as depth of focus) is performed.

  Here, the illuminance uniformity can be obtained, for example, by installing an illuminometer (detector or the like) on wafer stage WST and measuring the amount of illumination light IL at a plurality of locations in exposure area IA. The imaging performance of the projection optical system PL (for example, imaging characteristics in the Z direction (the optical axis direction of the projection optical system) such as the curvature of field, the tilt of the image plane, and the depth of focus) of the projection optical system PL is a predetermined value. It can be obtained using a measurement mask in which evaluation marks are formed at a plurality of positions. For example, an aerial image measuring device is used to change the pattern line width of an evaluation mark (aerial image) projected via the projection optical system PL while gradually changing the Z-direction position (focus position) of the wafer stage (Z tilt stage 38). The image forming characteristic in the Z direction of the projection optical system can be obtained by measuring using 59 and obtaining the Z direction position of the wafer stage when the mark is detected in the just focus state.

  Note that a method for measuring the imaging performance of the projection optical system PL using this aerial image measuring device 59 is disclosed in Japanese Patent Application Laid-Open Nos. 2002-198299, 2002-203762, and 2002-203763. This is described in detail in Japanese Unexamined Patent Publication No. 2002-324752. Instead of aerial image measurement, an evaluation mark may be exposed on a photosensitive substrate (wafer), and the pattern line width of the mark may be measured by an actual measurement method such as a scanning electron microscope (SEM) or an OCD method.

(Memory of operation sequence)
Next, the management apparatus 11 determines an operation sequence of the exposure apparatus 10 during a self-measuring operation described later (step 102). That is, the storage device 11C provided in the management apparatus 11 stores a plurality of types of operation sequences of the exposure apparatus 10, and the management apparatus 11 selects one of them as an operation sequence to be executed next. The selection of the operation sequence is performed based on, for example, an instruction from an operator or a higher-level management device that comprehensively manages the entire processing line.

  Here, the operation sequence includes a movement (scanning) sequence of the reticle stage RST and the wafer stage WST in the X and Y planes, a movement sequence of the Z tilt stage 38 related to autofocus and autoleveling (focus / leveling movement sequence). ), A setting sequence of the energy amount (exposure energy amount) of the laser beam LB from the light source 14, and the like.

  Of these, the movement sequence of reticle stage RST and wafer stage WST includes operation parameters such as the synchronous movement speed (scan speed), scan length (scan length), and exposure position of each stage RST and WST during the scanning exposure operation. Including. Here, the scanning length is a length by which the illumination light IL (exposure beam) is scanned on the wafer W when exposing each shot area, and the exposure position is the X, Y of the plurality of shot areas. This is a position in the plane and defines a shot area to be exposed. The exposure energy amount setting sequence determines a target value of the exposure energy amount for each shot area, and includes operation parameters such as on / off of laser light emission, center wavelength, spectrum half width, and repetition frequency.

(Exposure device operation)
Next, the management apparatus 11 operates the exposure apparatus 10 based on the operation sequence (step 103). The operation of exposure apparatus 10 at this time is performed in a state where wafer W (test wafer or process wafer for actual processing) is actually placed on wafer stage WST. At this time, the management apparatus 11 appropriately changes the synchronous movement speed, the scanning length, and the exposure position, which are the operation parameters in the movement sequence of the reticle stage RST and the wafer stage WST in the operation sequence of the exposure apparatus 10.

  For example, the management apparatus 11 causes the exposure apparatus 10 to perform a scanning exposure operation on all shot areas on the wafer W while maintaining a constant synchronous moving speed and scanning length, or synchronous moving speed and scanning length. The scanning exposure operation is performed with respect to one or a plurality of shot areas while changing at least one of them.

(Self-measurement operation)
The management apparatus 11 operates the exposure apparatus 10 while operating the predetermined performance of the exposure apparatus 10, specifically, (a) stage synchronization accuracy, (b) focus leveling followability, (c) exposure control accuracy, Information relating to the above is measured using a predetermined measuring apparatus provided in the exposure apparatus 10 (step 104). This self-measuring operation is performed every time the above-described operation parameters (synchronous movement speed, scanning length, exposure position) are changed. That is, the management apparatus 11 sequentially loads a plurality of operation parameters to the exposure apparatus 10 and receives data related to the above (a) to (c) from the exposure apparatus 10 every time the operation parameters are changed.

  Here, the stage synchronization accuracy is information relating to the accuracy of the synchronous movement (synchronous scanning) between the reticle R (reticle stage RST) and the wafer W (wafer stage WST) during the scanning exposure operation. Is obtained from detection signals and the like output from reticle stage interferometer 54R and wafer stage interferometer 54W. Specifically, the management apparatus 11 follows the reticle stage RST with respect to the wafer stage WST during scanning exposure from the position information of each stage RST and WST measured via the reticle stage interferometer 54R and the wafer stage interferometer 54W. Data on errors (X, Y) is collected, and moving average values (Xmean, Ymean) and moving standard deviation values (Xmsd, Ymsd, MSD: Moving Standard Deviation) are calculated as stage synchronization accuracy from this data.

  The focus leveling followability is information related to the attitude control (focusing control) of the wafer W during scanning exposure, and the detection signal of the focus position detection system (60a, 60b) when exposing each shot area on the wafer W. It is requested from. Specifically, the management device 11 detects position information (high in the optical axis direction) of each shot area on the wafer W (Z tilt stage 38) measured through the focus position detection system (60a, 60b) during scanning exposure. (Z), tilt about the X axis (roll θx), and tilt about the Y axis (pitch θy)) are collected, and the tracking error of wafer stage WST with respect to the target focus / leveling position as the focus leveling tracking capability (Z, θx, θy) is obtained. Note that the data collection of the stage synchronization accuracy and the measurement method of the focus leveling followability are described in detail in Japanese Unexamined Patent Application Publication No. 2003-100599.

  The exposure control accuracy is information relating to the exposure energy amount at the time of scanning exposure, and is obtained from the detection signal of the integrator sensor 46 when exposing each shot area on the wafer W. Specifically, the exposure apparatus 10 measures the energy amount (exposure energy amount) of the illumination light IL via the integrator sensor 46 at regular time intervals, and the management apparatus 11 determines the exposure control accuracy from the measurement data. As described above, an error of the actual exposure energy amount with respect to the target exposure energy amount when each shot area is exposed is obtained.

(Estimation calculation)
Then, when information related to the stage synchronization accuracy, focus leveling followability, exposure control accuracy is self-measured, the management device 11 includes the self-measurement information, process information and pre-information input or measured in advance. Based on the above, the line width uniformity (including the contrast of the pattern image) of the pattern image transferred onto the wafer W by the operation of the exposure apparatus 10 is estimated (simulated) (step 105).

Here, stage synchronization accuracy: MS, focus leveling followability: FO, exposure control accuracy: IA, illumination uniformity: IU, imaging optical system imaging characteristics: AB, resist performance: RE, developer material coefficient: DE When the other process parameter is OT, the line width uniformity: ΔCD is expressed by the following equation (1) (Function: function). Other process parameters (OT) include, for example, exposure wavelength, projection lens numerical aperture (NA), illumination σ, illumination conditions, evaluation mark pattern type (binary / halftone / Levenson, etc.), Evaluation mark line width, manufacturing variation of evaluation mark, target line width, pattern pitch, manufacturing variation of evaluation mark, and the like.
ΔCD = Function (MS, FO, IA, IU, AB, RE, DE, OT) (1)

  That is, a table (accumulated data) is created by previously obtaining the relationship between each information of MS to OT and line width uniformity, and the information MS to OT obtained at the time of actual evaluation is collated with the accumulated data. By doing so, the line width uniformity ΔCD can be estimated. In this example, each information of IU, AB, RE, DE, and OT is obtained before the self-measurement operation, and the management apparatus 11 creates a function by collating these pieces of information with the accumulated data. Based on the above, each information measured by MS, FO, and IA is added to the calculation (simulation based on convolution). Note that convolution refers to each function (f (x): Aerial image, g (x): synchronization accuracy,...)), Fourier transform of each function, product of each function is calculated, and inverse Fourier transform is performed on the product. To do. And the estimation calculation at this time is performed for every operation parameter set at the time of self-measurement. Note that the measurement of the line width of the pattern image at the time of creating the accumulated data may be performed using the aerial image measurement device 59 or may be performed by an actual measurement method such as a scanning electron microscope (SEM) or an OCD method.

FIG. 6 is a diagram schematically showing the evaluation method of this example described above.
As shown in FIG. 6, in the evaluation method of this example described above, the predetermined performance of the exposure apparatus 10, specifically, while the exposure apparatus 10 is operated (step-and-scan) in the same manner as the actual scanning exposure operation described above. Includes information relating to (a) stage synchronization accuracy, (b) focus leveling followability, and (c) exposure control accuracy, by using a predetermined measuring device (wafer stage interferometer 54W, Self-measurement is performed by reticle stage interferometer 54R, focus position detection systems 60a and 60b, integrator sensor 46), and the like. Prior to the self-measurement, information (prior measurement data) regarding (d) illumination uniformity and (e) imaging characteristics of the projection optical system PL is measured. Then, in addition to the pre-measurement data of (d) and (e), (f) based on the process information, the above information (a) to (c) is added in calculation, and the wafer W is processed by the exposure apparatus 10. The line width uniformity (and the contrast of the pattern image) transferred onto the pattern image is estimated and calculated.

  As described above, in the evaluation method of this example, simple and quantitative evaluation can be performed on the line width uniformity of the exposure apparatus 10 by an estimation calculation taking various information into account.

  In particular, in the evaluation method of this example, when self-measuring the information of (a) to (c) above, operation parameters (synchronous movement speed, scanning length, shot area) related to the scanning exposure operation are appropriately changed, Since the line width uniformity is calculated for each operation parameter, the exposure apparatus 10 can be more quantitatively evaluated.

  For example, the scanning exposure operation on the entire surface of the wafer W is evaluated by self-measuring the information (a) to (c) when the exposure operation is performed on all shot areas on the wafer W. Can do. The results of such evaluation are preferably used for comprehensive evaluation of the exposure apparatus 10.

  In addition, while changing the synchronous movement speed (scan speed) and the scan length (scan length), the information of the above (a) to (c) is self-measured and evaluated, so that the operation parameter and the line width are obtained. More information about the relationship with uniformity can be obtained. As a result, more preferable exposure conditions can be set for the scanning exposure operation of the exposure apparatus 10 based on the evaluation result.

  When the exposure apparatus 10 described above is evaluated, calibration is performed on the self-measuring measurement apparatus (wafer stage interferometer 54W, reticle stage interferometer 54R, focus position detection systems 60a and 60b, integrator sensor 46). It is preferable to leave. Among the measurement devices, the calibration of the focus position detection systems 60 a and 60 b and the integrator sensor 46 can be performed using an aerial image measurement method using the aerial image measurement device 59. Techniques relating to calibration using the aerial image measurement method are described in detail in Japanese Patent Application Laid-Open Nos. 2002-198299, 2002-203762, 2002-203763, and the like. Further, information used in the evaluation method may be measured using this calibration process.

  In the above-described embodiment, the case where the present invention is applied to an exposure apparatus for manufacturing a semiconductor has been described. However, the present invention is not limited to this, and for example, exposure for liquid crystal that transfers a liquid crystal display element pattern onto a square glass plate. The present invention can be widely applied to an apparatus, an exposure apparatus for manufacturing a thin film magnetic head, an image sensor, a micromachine, a DNA chip, a reticle, a mask, and the like.

In the above-described embodiment, the case where KrF excimer laser light (248 nm), ArF excimer laser light (193 nm), or the like is used as the illumination light for exposure has been described. However, the present invention is not limited to this. 365 nm), F ₂ laser light (157 nm), copper vapor laser, harmonics of YAG laser, and the like can be used as illumination light for exposure.

  In the above embodiment, the case where the reduction system is used as the projection optical system has been described. However, the present invention is not limited to this, and an equal magnification or enlargement system may be used as the projection optical system. Any of the reflection systems may be used.

  An illumination optical system and projection optical system composed of multiple lenses are incorporated into the exposure apparatus body for optical adjustment, and a reticle stage and wafer stage consisting of numerous mechanical parts are attached to the exposure apparatus body to connect wiring and piping. Furthermore, the exposure apparatus of the present embodiment can be manufactured by further comprehensive adjustment (electrical adjustment, operation check, etc.). The exposure apparatus is preferably manufactured in a clean room where the temperature, cleanliness, etc. are controlled.

  Next, an embodiment of a device manufacturing method using the above-described exposure apparatus in a lithography process will be described.

  FIG. 7 shows a flowchart of 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 201 (design step), device function / performance design (for example, circuit design of a semiconductor device) is performed, and pattern design for realizing the function is performed. Subsequently, in step 202 (mask manufacturing step), a mask on which the designed circuit pattern is formed is manufactured. On the other hand, in step 203 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

  Next, in step 204 (wafer processing step), using the mask and wafer prepared in steps 201 to 203, an actual circuit or the like is formed on the wafer by lithography or the like as will be described later. Next, in step 205 (device assembly step), device assembly is performed using the wafer processed in step 204. Step 205 includes processes such as a dicing process, a bonding process, and a packaging process (chip encapsulation) as necessary.

  Finally, in step 206 (inspection step), inspections such as an operation confirmation test and durability test of the device created in step 205 are performed. After these steps, the device is completed and shipped.

  FIG. 8 shows a detailed flow example of step 204 in the semiconductor device. In FIG. 8, in step 211 (oxidation step), the surface of the wafer is oxidized. In step 212 (CVD step), an insulating film is formed on the wafer surface. In step 213 (electrode formation step), an electrode is formed on the wafer by vapor deposition. In step 214 (ion implantation step), ions are implanted into the wafer. Each of the above-described steps 211 to 214 constitutes a pre-processing 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 pre-process is completed, the post-process is executed as follows. In this post-processing process, first, in step 215 (resist formation step), a photosensitive agent is applied to the wafer. Subsequently, in step 216 (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 218 (etching step), the exposed member in a portion other than the portion where the resist remains is removed by etching. In step 219 (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 this embodiment described above is used, the exposure apparatus of the above embodiment is used in the exposure step (step 216). Therefore, the reticle pattern can be accurately placed on the wafer under optimized exposure conditions. Can be transferred. As a result, it becomes possible to improve the productivity (including yield) of highly integrated devices.

  As described above, the preferred embodiments according to the present invention have been described with reference to the accompanying drawings, but the present invention is not limited to the examples. It is obvious for those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims. It is understood that it belongs to.

It is a figure which shows schematic structure of the exposure system which concerns on one Embodiment of this invention. FIG. 2 is an enlarged view of the vicinity of the wafer stage of FIG. It is a figure which shows the internal structure of the aerial image measuring device of FIG. FIG. 4A is a diagram showing a state in which the aerial image PMy ′ is formed on the slit plate during the aerial image measurement, and FIG. 4B is a photoelectric conversion signal obtained during the aerial image measurement. It is a diagram which shows an example of (light intensity signal). It is a flowchart which shows the procedure of the evaluation method of the exposure apparatus by a management apparatus. It is a figure which shows typically the evaluation method of FIG. It is a flowchart for demonstrating embodiment of the device manufacturing method which concerns on this invention. It is a flowchart figure which shows the manufacturing method of a semiconductor element.

Explanation of symbols

  R ... reticle (mask), RST ... reticle stage (mask stage), W ... wafer (substrate), WST ... wafer stage (substrate stage), 10 ... exposure device, 11 ... management device (arithmetic device), 11A ... input device , 11B, 11C ... storage device, 46 ... integrator sensor (photoelectric sensor), 50 ... control device, 54W ... wafer stage interferometer (second interferometer), 54R ... reticle stage interferometer (first interferometer), 60a, 60b: Focus position detection system (focus / leveling sensor), 100: Exposure system.

Claims (22)

A mask stage for placing a mask and moving in a two-dimensional plane and a substrate stage for placing a substrate and moving in a two-dimensional plane are provided, and the mask is moved with an exposure beam while both stages are moved synchronously. An exposure apparatus evaluation method for illuminating and evaluating a predetermined performance of a scanning exposure apparatus that sequentially exposes a pattern on the mask on a plurality of partitioned regions on the substrate,
A first step of storing an operation sequence when performing exposure of the pattern on a predetermined partition region on the substrate;
A second step of operating the scanning exposure apparatus while changing the setting of operation parameters related to the exposure operation in the operation sequence;
When operating the scanning exposure apparatus in the second step, information on the first characteristic of the scanning exposure apparatus is obtained using a measuring device provided in the scanning exposure apparatus, A third step of measuring each time it is changed;
And a fourth step of estimating (simulating) the predetermined performance of the scanning exposure apparatus based on information on the plurality of first characteristics measured in the third step. Evaluation method.   The operating parameters include a synchronous movement speed of the two stages, a length of scanning of the exposure beam on the substrate when exposing the partition area, and positions of the plurality of partition areas on the two-dimensional plane. The evaluation method according to claim 1, comprising at least one of the following. A mask stage for placing a mask and moving in a two-dimensional plane and a substrate stage for placing a substrate and moving in a two-dimensional plane are provided, and the mask is moved with an exposure beam while both stages are moved synchronously. An exposure apparatus evaluation method for illuminating and evaluating a predetermined performance of a scanning exposure apparatus that sequentially exposes a pattern on the mask on a plurality of partitioned regions on the substrate,
A first step of storing an operation sequence when performing exposure of the pattern on a plurality of partitioned regions on the substrate;
A second step of operating the scanning exposure apparatus based on the operation sequence;
A measurement provided in the scanning exposure apparatus for information related to the first characteristic of the scanning exposure apparatus when the scanning exposure apparatus is operated for the plurality of partitioned areas in the second step. A third step of measuring for each of the plurality of partitioned areas using an apparatus;
And a fourth step of estimating (simulating) the predetermined performance of the scanning exposure apparatus based on information on the plurality of first characteristics measured for each of the plurality of partitioned regions in the third step. An evaluation method of an exposure apparatus characterized by the above.   The predetermined performance includes at least one of a uniformity of a line width of a pattern image transferred onto the substrate by an exposure operation of the scanning exposure measure and a contrast of the pattern image. The evaluation method as described in any one of 1-3. The operation sequence includes a movement sequence of the mask stage and the substrate stage in the two-dimensional plane,
In the second step, both stages are moved based on the movement sequence,
The measurement apparatus includes a first interferometer that measures position information of the mask stage, and a second interferometer that measures position information of the substrate stage,
In the third step, information on the synchronization accuracy between the two stages as the first characteristic is measured based on an output from the first interferometer and an output from the second interferometer. The evaluation method according to any one of claims 1 to 4. The operation sequence includes a focus / leveling movement sequence of the substrate stage in a direction orthogonal to the two-dimensional plane,
In the second step, the substrate stage is moved based on the focus / leveling movement sequence,
The measurement apparatus includes a focus / leveling sensor that measures information on the position of the substrate placed on the substrate stage in the orthogonal direction and the tilt with respect to the orthogonal direction,
2. In the third step, information on the followability of the substrate stage as the first characteristic with respect to a target focus / leveling position is measured based on an output from the focus / leveling sensor. The evaluation method as described in any one of -5. The operation sequence includes a setting sequence of an exposure energy amount when exposing the substrate,
In the second step, an exposure energy amount for the plurality of partitioned areas is set based on the setting sequence,
The measuring device includes a photoelectric sensor that measures an actual exposure energy amount of an exposure beam emitted with a target exposure energy amount set in the second step,
In the third step, information relating to an error of an actual exposure energy amount with respect to the target exposure energy amount as the first characteristic is measured based on an output from the photoelectric sensor. The evaluation method as described in any one of 6. Before performing the second step, further includes a fifth step of measuring in advance information relating to the second characteristic of the scanning exposure apparatus;
In the fourth step, the predetermined calculation is performed by executing the estimation calculation using the information on the first characteristic obtained in the third step and the information on the second characteristic obtained in the fifth step. The evaluation method according to claim 1, wherein the performance is estimated.   9. The evaluation method according to claim 8, wherein the second characteristic includes energy uniformity of the exposure beam in an irradiation region where the exposure beam for exposing the substrate is irradiated onto the substrate.   The evaluation method according to claim 8 or 9, wherein the second characteristic includes an imaging characteristic of a projection optical system that projects a pattern on the mask onto the substrate. A sixth step of inputting information on at least one of information on a photosensitive material coating process on the substrate and information on a development process on the substrate;
In the fourth step, the information on the first characteristic obtained in the third step, the information on the second characteristic obtained in the fifth step, and the information obtained in the sixth step are used. The evaluation method according to claim 1, wherein the predetermined performance is estimated by executing the estimation calculation. A step of optimizing exposure conditions set in the scanning exposure apparatus so that the predetermined performance is best based on the evaluation result by the evaluation method according to any one of claims 1 to 11,
Transferring the device pattern formed on the mask onto the substrate using the optimized exposure apparatus. A mask stage for placing a mask and moving in a two-dimensional plane and a substrate stage for placing a substrate and moving in a two-dimensional plane are provided, and the mask is moved with an exposure beam while both stages are moved synchronously. An exposure system for illuminating and estimating a predetermined performance of a scanning exposure apparatus that sequentially exposes a pattern on the mask on a plurality of partitioned regions on the substrate,
A storage device for storing an operation sequence when the pattern is exposed to a predetermined partition area on the substrate;
A control device for operating the scanning exposure apparatus while changing the setting of operation parameters related to the exposure operation in the operation sequence;
A measuring device for measuring information on the first characteristic of the scanning exposure apparatus each time the operating parameter is changed when the scanning exposure apparatus is operating under the control of the control device;
An exposure system comprising: an arithmetic unit that estimates and calculates the predetermined performance of the scanning exposure apparatus based on information on the plurality of first characteristics measured by the measurement apparatus.   The operating parameters include a synchronous movement speed of the two stages, a length of scanning of the exposure beam on the substrate when exposing the partition area, and positions of the plurality of partition areas on the two-dimensional plane. 14. The exposure system according to claim 13, comprising at least one of the following. A mask stage for placing a mask and moving in a two-dimensional plane and a substrate stage for placing a substrate and moving in a two-dimensional plane are provided, and the mask is moved with an exposure beam while both stages are moved synchronously. An exposure system for illuminating and estimating a predetermined performance of a scanning exposure apparatus that sequentially exposes a pattern on the mask on a plurality of partitioned regions on the substrate,
A storage device for storing an operation sequence when the pattern is exposed to a plurality of partitioned regions on the substrate;
A control device for operating the scanning exposure apparatus based on the operation sequence;
A measuring device that measures information about the first characteristic of the scanning exposure apparatus for each of the plurality of partitioned areas when the scanning exposure apparatus is operated under the control of the control device;
An arithmetic unit that estimates and calculates the predetermined performance of the scanning exposure apparatus based on information about the plurality of first characteristics measured for each of the plurality of partitioned regions by the measurement apparatus. Exposure system.   16. The predetermined performance includes at least one of a uniformity of a line width of a pattern image transferred onto the substrate by the scanning exposure apparatus and a contrast of the pattern image. The exposure system according to any one of the above. The operation sequence includes a movement sequence of the mask stage and the substrate stage in the two-dimensional plane,
The control device moves the both stages based on the movement sequence,
The measurement apparatus includes a first interferometer that measures position information of the mask stage, and a second interferometer that measures position information of the substrate stage, and synchronization between the two stages as the first characteristic. The exposure system according to any one of claims 13 to 16, wherein information on accuracy is measured based on an output from the first interferometer and an output from the second interferometer. The operation sequence includes a focus / leveling movement sequence of the substrate stage in a direction orthogonal to the two-dimensional plane,
The control apparatus moves the substrate stage based on the focus / leveling movement sequence,
The measurement apparatus includes a focus / leveling sensor that measures information on a position of the substrate placed on the substrate stage in the orthogonal direction and an inclination with respect to the orthogonal direction, and the substrate stage as the first characteristic The exposure system according to any one of claims 13 to 17, wherein information relating to the followability to the target focus / leveling position is measured based on an output from the focus / leveling sensor. The operation sequence includes a setting sequence of an exposure energy amount when exposing the substrate,
The control device sets an exposure energy amount for the plurality of partitioned regions based on the setting sequence,
The measuring device includes a photoelectric sensor for measuring an actual exposure energy amount of an exposure beam emitted with a target exposure energy amount set by the control device, and the target exposure energy amount as the first characteristic 19. The exposure system according to claim 13, wherein information relating to an error in an actual exposure energy amount with respect to is measured based on an output from the photoelectric sensor. A second storage device that is provided separately from the measurement device and stores information related to a second characteristic of the exposure apparatus different from the first characteristic;
The said arithmetic unit estimates the said predetermined performance by performing the said estimation calculation using the information regarding the said 1st characteristic, and the information regarding the said 2nd characteristic, The any one of Claims 13-19 characterized by the above-mentioned. The exposure system according to one item.   The information on the second characteristic is information on energy uniformity of the exposure beam in an irradiation region where the exposure beam for exposing the substrate is irradiated onto the substrate, and a pattern on the mask is projected onto the substrate. 21. The exposure system according to claim 20, comprising at least one of information relating to imaging characteristics of the projection optical system. An input device that inputs information on at least one of information on a coating process of a photosensitive material on the substrate and information on a development process on the substrate;
The arithmetic device estimates the predetermined performance by executing the estimation operation using information related to the first characteristic, information related to the second characteristic, and information input to the input device. The exposure system according to any one of claims 13 to 21.

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