JP2020003617A - Exposure equipment, exposure method and method for production of article - Google Patents

Abstract

To provide an advantageous technique for controlling a substrate posture at high accuracy in scanning exposure of the substrate.SOLUTION: Exposure equipment which performs exposure of a substrate by moving a light irradiation area on the substrate while scanning the substrate includes: a first measurement part measuring sequentially each height of plural measurement object places arranged on the substrate along a scanning direction during the scan of the substrate before each measurement object place enters the light irradiation area; a second measurement part measuring sequentially the above each height during the substrate scanning before the measurement by the first measurement part is carried out; and a control part controlling the substrate posture during the above scan. The control part specifies abnormal places among plural measurement object places on the basis of the measurement result of each object place by the second measurement part, and controls the substrate posture without using the measurement result by the first measurement part in the abnormal places.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exposure apparatus, an exposure method, and a method for manufacturing an article.

  As one of apparatuses used in a manufacturing process (lithography process) of a semiconductor device or the like, a substrate is scanned to move a light irradiation region irradiated with light from a projection optical system on a shot region of the substrate. There is an exposure apparatus that performs scanning exposure of a shot area. In such an exposure apparatus, during scanning exposure of the shot area, the height of the substrate surface is measured prior to the arrangement of the light irradiation area, and based on the measurement result, the substrate surface in the light irradiation area is adjusted by the projection optical system. The posture of the substrate is controlled so as to fall within the allowable focus range (see Patent Document 1).

  Further, in the exposure apparatus, for example, a step may be formed on the substrate due to adhesion of a foreign substance or the like. In this case, if the posture of the substrate is controlled based on the measurement result of the step, defocus occurs in a part of the substrate, and it may be difficult to form a pattern on the substrate with high accuracy. Patent Document 2 discloses that when there is measurement data exceeding a predetermined allowable value among measurement data obtained by pre-read measurement, the height of the substrate is adjusted by excluding the measurement data. .

JP-A-9-45608 JP 2003-115454 A

  In the exposure apparatus, it is desired to increase the scanning speed of the substrate in order to improve the throughput, and the period from when the pre-read measurement is performed to when the light irradiation area is arranged tends to be shorter. Therefore, as described in Patent Document 2, in the method of determining whether or not the measurement data itself can be used for adjusting the height of the substrate based on the measurement data obtained by the pre-read measurement, the determination period is short. It may be difficult to adjust the height of the substrate to follow the scanning of the substrate.

  Therefore, an object of the present invention is to provide an advantageous technique for accurately controlling the posture of a substrate in scanning exposure of the substrate.

  In order to achieve the above object, an exposure apparatus as one aspect of the present invention is an exposure apparatus that performs exposure of a substrate by moving a light irradiation area on the substrate while scanning the substrate, During the scanning, a first measurement unit that sequentially measures the height of each of the plurality of measurement target locations arranged on the substrate along the scanning direction before each measurement target location enters the light irradiation region. A second measuring unit that sequentially measures the height of each of the plurality of measurement target positions before the first measuring unit performs the measurement, during the scanning of the substrate, A control unit that controls the posture of the substrate during scanning of the substrate, based on the measurement result, wherein the control unit performs the plurality of measurement based on the measurement result of each measurement target portion by the second measurement unit. An abnormal point is identified from the measurement target points of Wherein controlling the attitude of the substrate without using the measurement result in the first measurement unit in, characterized in that.

  Further objects and other aspects of the present invention will become apparent from the preferred embodiments described below with reference to the accompanying drawings.

  According to the present invention, for example, it is possible to provide an advantageous technique for accurately controlling the posture of a substrate in scanning exposure of the substrate.

FIG. 1 is a diagram illustrating an overall configuration of an exposure apparatus according to a first embodiment. FIG. 3 is a diagram illustrating a positional relationship between a shot area, a plurality of measurement points by a focus tilt measurement unit, and a light irradiation area. FIG. 3 is a diagram illustrating a flowchart of an exposure process according to the first embodiment. FIG. 3 is a diagram showing the positional relationship between a shot area, a plurality of measurement points by a focus tilt measurement unit, and a light irradiation area over time. It is a figure for explaining processing for specifying an abnormal place. FIG. 6 is a diagram illustrating an overall configuration of an exposure apparatus according to a second embodiment.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. In each of the drawings, the same members or elements are denoted by the same reference numerals, and redundant description will be omitted. A “measurement point” used in the following embodiments is defined as an element of each of a plurality of measurement marks at a measurement location.

<First embodiment>
[Configuration of exposure apparatus]
A first embodiment according to the present invention will be described. FIG. 1 is a diagram illustrating an overall configuration of an exposure apparatus 1 according to the present embodiment. In FIG. 1, an exposure apparatus 1 scans a substrate to move a light irradiation area irradiated with light from a projection optical system on a shot area of the substrate, and performs scanning exposure of the shot area. This is an AND-scan type exposure apparatus. Such an exposure apparatus 1 is also called a scanning exposure apparatus or a scanner, and is capable of transferring a circuit pattern formed on an original onto a substrate by performing scanning exposure of a shot area. In the present embodiment, the original is a reticle R made of, for example, quartz, on which a circuit pattern to be transferred to each shot area of the substrate is formed. Further, the substrate is a wafer W coated with a photoresist, and for example, a single crystal silicon substrate or the like can be used.

  The exposure apparatus 1 includes an illumination device 10, a reticle stage 25 capable of holding and moving a reticle R, a projection optical system 30, a wafer stage 45 capable of holding and moving a wafer W, and a focus tilt measuring unit 50. , An alignment detection unit 70, and a control unit 60. The control unit 60 is configured by, for example, a computer having a CPU and a memory, and is electrically connected to each unit in the apparatus, and controls the overall operation of the apparatus.

  The illumination device 10 includes a light source unit 12 and an illumination optical system 14, and illuminates a part of the reticle R on which a circuit pattern to be transferred to the wafer W is formed.

The light source unit 12 may include, for example, a KrF excimer laser that emits a laser beam having a wavelength of about 248 nm, an ArF excimer laser that emits a laser beam having a wavelength of about 193 nm, or the like. The light source unit 12 is not limited to those of the excimer laser, F ₂ laser or for emitting a laser beam having a wavelength of approximately 157 nm, and EUV (Extreme Ultra Violet) light source for emitting light below a wavelength 20nm May be included.

  The illumination optical system 14 is an optical system that illuminates the reticle R using the light beam emitted from the light source unit 12, and shapes the light beam into predetermined slit light optimal for exposure to illuminate a part of the reticle R. . The illumination optical system 14 includes a lens, a mirror, an optical integrator, a stop, and the like. For example, a condenser lens, a fly-eye lens, an aperture stop, a condenser lens, a slit, and an imaging optical system are arranged in this order. The illumination optical system 14 can be used regardless of on-axis light or off-axis light. The optical integrator includes a fly-eye lens and an integrator formed by stacking two sets of cylindrical lens array (or lenticular lens) plates, but may be replaced with an optical rod or a diffraction element.

  Reticle stage 25 may include a reticle chuck that holds reticle R, and a drive mechanism that drives reticle R together with the reticle chuck. This drive mechanism is configured by, for example, a linear motor or the like, and can drive the reticle R in the X-axis direction, the Y-axis direction, the Z-axis direction, and the rotation direction of each axis. Therefore, reticle stage 25 can drive reticle R in the Y direction, which is the scanning direction, during the scanning exposure of wafer W. The position of the reticle stage 25 can be monitored by, for example, a laser interferometer.

  The wafer stage 45 may include a wafer chuck 46 for holding the wafer W, and a driving mechanism for driving the wafer W together with the wafer chuck. The driving mechanism is configured by, for example, a linear motor or the like, and can drive the wafer W in the X-axis direction, the Y-axis direction, the Z-axis direction, and the rotation direction of each axis. Accordingly, the wafer stage 45 can drive the wafer W in the Y direction, which is the scanning direction, during the scanning exposure of the wafer W. The position of the wafer stage 45 can be monitored by, for example, a laser interferometer.

  The projection optical system 30 has a function of forming a light beam from an object plane on an image plane, and forms a partial pattern of the reticle R illuminated by the illumination optical system 14 onto the wafer W at a predetermined projection magnification. Image (projection). An area on the wafer W to which light from the projection optical system 30 is irradiated may be referred to as a “light irradiation area” below. Further, the alignment detection unit 70 detects a mark on the wafer W, and obtains an arrangement (position) of each shot area on the wafer W. In the example shown in FIG. 1, the off-axis system is configured to detect the mark on the wafer W without the intervention of the projection optical system 30, but the TTL (TTL) for detecting the mark on the wafer W via the projection optical system 30 is used. Through The Lens) method.

  In the exposure apparatus 1 configured as described above, the reticle R and the wafer W are arranged at positions substantially optically conjugate via the projection optical system 30 (the object plane and the image plane of the projection optical system 30). The control section 60 relatively synchronously scans the reticle R and the wafer W with the reticle stage 25 and the wafer stage 45 at a speed ratio corresponding to the projection magnification of the projection optical system 30, thereby changing the pattern of the reticle R to the wafer W. Can be transferred on top. Then, such scanning exposure is sequentially repeated for each of the plurality of shot areas on the wafer W while moving the wafer stage 45 stepwise, whereby the exposure processing on one wafer W can be completed.

[Configuration of focus tilt measurement unit]
Next, the configuration of the focus tilt measuring unit 50 will be described. The focus tilt measurement unit 50 includes a light projector 52 that projects measurement light onto the wafer W, and a light receiver 54 that receives measurement light reflected by the wafer W, and scans the surface of the wafer W during scanning of the wafer W. The height (surface position in the Z-axis direction) is sequentially measured. The light projector 52 projects the dot-shaped or slit-shaped measurement light (measurement mark) onto the wafer W at a high incident angle. In the present embodiment, an example in which dot-shaped measurement light is projected on the wafer W will be described. The light projector 52 has a photoelectric conversion element such as a CMOS sensor, for example, and forms an image of the measurement light reflected by the wafer W on the photoelectric conversion element, and projects the measurement light based on a signal from the photoelectric conversion element. Find the surface height of the illuminated location.

  FIG. 2 is a diagram illustrating a positional relationship between the shot region SR of the wafer W, a plurality of measurement points MP by the focus tilt measurement unit 50, and the light irradiation region ES. The measurement point MP is a position on the wafer W at which the surface height of the wafer W is measured by emitting the dot-shaped measurement light by the light projector 52, and according to the scanning of the wafer W, the light irradiation area ES Together with the wafer W. Arrows F and R in the figure indicate the scanning direction of the wafer W, and can be switched for each shot region SR.

  The focus tilt measurement unit 50 of the present embodiment includes an area measurement unit that measures a surface height in the light irradiation area ES, a first measurement unit that measures the surface height prior to the arrangement of the light irradiation area ES, A second measurement unit that measures the surface height prior to measurement by the first measurement unit. In the example illustrated in FIG. 2, the area measurement unit measures the surface height of the wafer W at the measurement points MP3 to MP5 in the light irradiation area ES. The first measurement unit is also referred to as a so-called pre-read measurement unit, and measures the surface height of the wafer W at the measurement points MP6 to MP8 or the measurement points MP12 to MP14 separated from the light irradiation area ES by a distance Lp1. The second measurement unit is also called a prefetch measurement unit, and measures the surface height of the wafer W at the measurement points MP9 to MP11 or the measurement points MP15 to MP17 separated from the light irradiation area ES by the distance Lp2. The relationship between the distance Lp1 and the distance Lp2 is Lp1 <Lp2.

  Here, the measurement points MP3 to MP5 may be arranged apart from each other in a direction different from the scanning direction of the wafer W (for example, a direction (X direction) perpendicular to the scanning direction). The same applies to each set of the measurement points MP6 to MP8, the measurement points MP9 to MP11, the measurement points MP12 to MP14, and the measurement points MP15 to MP17, and the measurement points are arranged apart from each other in a direction intersecting the scanning direction of the wafer W. Is done. Further, MP3, MP6, MP9, MP12 and MP15 can be arranged at substantially the same X coordinate position. Similarly, MP4, MP7, MP10, MP13 and MP16 can be arranged at substantially the same X coordinate position, and MP5, MP8, MP11, MP14 and MP17 can be arranged at substantially the same X coordinate position. Further, FIG. 2 shows an example in which three measurement points are arranged in a direction (X direction) different from the scanning direction of the wafer W, but the number of measurement points arranged in the different directions is limited to three. Instead, two or four or more may be used.

  In the focus tilt measurement unit 50 configured as described above, the measurement timing at each of the measurement points MP3 to MP17 can be controlled by the control unit 60. For example, based on the distance between the light irradiation area ES and each of the measurement points MP3 to MP17, the scanning direction and the scanning speed of the wafer stage 45, the control unit 60 determines the measurement points MP3 to MP17 of the focus tilt measurement unit 50. Controls measurement timing. Accordingly, the height of the same measurement target portion (the same XY coordinate position) on the wafer W while scanning the wafer W in the Y direction by each of the plurality of measurement points MP arranged at substantially the same X coordinate. Can be measured.

[About scanning exposure]
In the exposure apparatus 1 configured as described above, the surface tilt of the wafer W is measured by the focus tilt measurement unit 50 prior to the arrangement of the light irradiation area ES while scanning the wafer W during the scanning exposure of the shot area SR. (A prefetch measurement is performed). Then, based on the measurement result, the attitude of the wafer W is controlled (adjusted) so that the surface of the wafer W in the light irradiation area ES falls within the allowable focus range of the projection optical system 30. In such scanning exposure of the shot region SR, it is better to shorten the period from when the pre-read measurement is performed to when the light irradiation region ER is arranged, because environmental time-dependent changes such as atmospheric pressure fluctuation and temperature fluctuation during the scanning exposure are reduced. Less likely to be affected. Therefore, in the exposure apparatus 1 of the present embodiment, at the time of scanning exposure of the shot area SR, based on the measurement result of the first measuring unit (the measuring points MP6 to MP8 or the measuring points 12 to 14) of the focus tilt measuring unit 50. Thus, the attitude of the wafer W is controlled.

  Incidentally, in the exposure apparatus, for example, a step may be generated on the wafer W due to foreign matter (particles) adhering to the wafer W. In this case, when the attitude of the wafer W is controlled based on the result of the measurement of the step by the focus tilt measurement unit 50, defocus occurs in a part of the wafer W, and the pattern of the reticle R is transferred onto the wafer W with high accuracy. That can be difficult. Therefore, the exposure apparatus determines whether or not the measurement result of the first measurement unit of the focus tilt measurement unit 50 can be used for controlling the attitude of the wafer W, and uses the wafer W without using the measurement result determined to be unusable. It is preferable to perform the posture control described above.

  However, it is desired that the exposure apparatus increase the scanning speed of the wafer W to improve the throughput, and the light irradiation area ES is not changed after the pre-read measurement is performed by the first measurement unit of the focus tilt measurement unit 50. There is a tendency for the period until it is arranged to be shorter. In such a situation, if it is determined whether or not the measurement result of the first measurement unit can be used for controlling the attitude of the wafer W based on the measurement result of the first measurement unit, a determination period And the attitude control of the wafer W may be difficult to follow the scanning of the wafer W.

  Therefore, in the exposure apparatus 1 of the present embodiment, based on the measurement result by the second measurement unit of the focus tilt measurement unit 50, an abnormal location having an abnormality is selected from a plurality of measurement target locations set on the wafer W. Identify. Then, the attitude of the wafer W when the light irradiation area ES is arranged is controlled without using the measurement result of the first measurement unit of the focus tilt measurement unit 50 at the abnormal location. Here, the “posture of the wafer W” can be defined as including both the inclination of the wafer W and the height (position in the Z direction) of the wafer W. Further, “abnormality” can be defined as a surface height measured by the focus tilt measurement unit 50 that is locally peculiar to another measurement target portion due to, for example, adhesion of a foreign substance.

  Next, an exposure process in the exposure apparatus 1 of the present embodiment will be described with reference to FIGS. The exposure process is a process of measuring the surface height of the measurement target portion in the shot region SR while scanning the wafer W and exposing the wafer W. FIG. 3 is a diagram showing a flowchart of the exposure processing of the present embodiment. FIG. 4 is a diagram showing the positional relationship between the shot region SR of the wafer W, the plurality of measurement points MP by the focus tilt measurement unit 50, and the light irradiation region ES over time.

  As shown in FIG. 4A, a plurality of measurement target locations TP whose surface heights are to be measured by the focus tilt measurement unit 50 are set (arranged) in the shot area SR. The measurement target locations TP11 to TP13 are measurement target locations where the surface height is measured first by the focus tilt measurement unit 50 when the wafer W is scanned in the direction of arrow F in the drawing. The measurement target locations TP11 to TP13 are arranged along a direction different from the scanning direction so as to correspond to positions of a plurality of (three) measurement points MP arranged along a direction (X-axis direction) different from the scanning direction. They can be spaced apart. The measurement target locations TP21 to TP23 are set so as to be measured next to the measurement target locations TP11 to TP13, and the measurement target locations TP31 to TP33 are set to be measured next to the measurement target locations TP21 to TP23. sell.

  Here, in the present embodiment, in the scanning direction F of the wafer W, the interval between the first measurement unit (measurement points MP6 to MP8) and the second measurement unit (measurement points MP9 to MP11) is determined by the measurement target locations TP11 to TP13. And the distance between the measurement target portions TP31 to TP33. Further, in the present embodiment, an example in which the surface height is measured at the measurement target locations TP11 to TP33 will be described in order to make the description easy to understand, and FIG. 4 illustrates the measurement target locations other than the measurement target locations TP11 to TP33. Omitted. However, in practice, a plurality of rows of measurement target locations arranged at predetermined intervals in the scanning direction are set over the entire range of the shot region SR, and the same processing as the processing at the measurement target locations TP11 to TP33 is performed. Can be repeated.

  In S11, the control unit 60 starts scanning drive of the wafer W to perform scanning exposure of the shot region SR. In S12, the control unit 60 starts measuring the surface height of the measurement target location by the second measurement unit (measurement points MP9 to MP11). For example, the control unit 60 causes the second measurement unit to measure the surface height of the measurement target locations TP11 to TP13 at the timing when the second measurement unit is arranged at the measurement target locations TP11 to TP13 while scanning the wafer W. (FIG. 4 (b)). Further, the control unit 60 measures the surface heights of the measurement target locations TP21 to TP23 in the second measurement unit at the timing when the second measurement unit is arranged at the measurement target locations TP21 to TP23 while continuously scanning the wafer W. (FIG. 4C). Similarly, while continuously scanning the wafer W, the control unit 60 causes the second measurement unit to change the surface height of the measurement target locations TP31 to TP33 at the timing when the second measurement unit is disposed at the measurement target locations TP31 to TP33. Let me measure.

  In S13, the control unit 60 specifies an abnormal part having an abnormality based on the measurement results of the second measurement units (measurement points MP9 to MP11). In the example illustrated in FIG. 4, the control unit 60 specifies an abnormal location from the measurement target locations TP11 to TP33. For example, the control unit 60 obtains the correlation of the measurement results at a plurality of measurement target locations (for example, TP11, TP21, TP31) arranged along the scanning direction, and the correlation exceeds the allowable range. The measurement target location can be specified as an abnormal location. The control unit 60 may calculate, as the correlation, a difference between the measurement results between the plurality of measurement target locations arranged along the scanning direction, or may calculate the ratio of the measurement results between the plurality of measurement target locations. You may ask. In addition, the allowable range is set based on the depth of focus (DOF), the pattern line width, the exposure illumination mode, and the like, and may be set by a user via a user interface, for example.

  FIG. 5 is a diagram illustrating a specific process for identifying an abnormal location from a plurality of measurement target locations. Here, an example will be described in which a difference between the measurement results between the measurement target portions TP11, TP21, and TP31 arranged along the scanning direction is obtained as a correlation, and an abnormal portion is identified from the difference. The upper diagram of FIG. 5 shows the surface height measured at each of the measurement target portions TP11, TP21, and TP31, and the lower diagram of FIG. 5 shows the difference between the measurement target portions TP11, TP21, and TP31. . In the figure, ΔZ12 is the difference in surface height between the measurement target locations TP11 and TP21, ΔZ23 is the difference in surface height between the measurement target locations TP21 and TP31, and ΔZ31 is the difference between the measurement target location TP31. The difference of the surface height from TP11 is shown.

  As shown in FIG. 5A, when the measurement results of the surface heights at the measurement target locations TP11, TP21, and TP31 are almost the same, and ΔZ12, ΔZ23, and ΔZ31 do not exceed the allowable range ZA, respectively, The control unit 60 can determine that there is no abnormal point. On the other hand, as shown in FIG. 5B, when ΔZ23 does not exceed the allowable range ZA, but ΔZ12 and Δ31 exceed the allowable range ZA, the control unit 60 determines that the measurement target location TP11 is an abnormal location. Can be determined (specified). Further, as shown in FIG. 5C, when ΔZ31 does not exceed the allowable range ZA, but ΔZ12 and ΔZ23 exceed the allowable range ZA, the control unit 60 determines that the measurement target location TP21 is an abnormal location. Can be determined (specified). The same process is performed on the set of the measurement target locations TP12, TP22, and TP32 and the set of the measurement target locations TP13, TP23, and TP33, and the abnormal location can be specified for each set. Here, in the example illustrated in FIG. 4, it is assumed that the measurement target location TP <b> 11 indicated by the triangle is identified as an abnormal location by performing the above-described processing.

  In S14, the control unit 60 starts measuring the surface height of the measurement target location by the first measurement unit (measurement points MP6 to MP8). For example, the control unit 60 causes the first measurement unit to measure the surface heights of the measurement target locations TP11 to TP13 at the timing when the first measurement unit is arranged at the measurement target locations TP11 to TP13 while scanning the wafer W. (FIG. 4D). Similarly, while continuously scanning the wafer W, the control unit 60 causes the first measurement unit to change the surface height of the measurement target locations TP21 to TP23 at the timing when the first measurement unit is disposed at the measurement target locations TP21 to TP23. The measurement is performed (FIG. 4E).

  In S15, the control unit 60 determines whether each measurement target location enters (is placed) the light irradiation area ES based on the measurement result of the surface height of the measurement target location by the first measurement units (MP6 to MP8). The target attitude of the wafer W is determined (calculated). At this time, the control unit 60 can determine the target attitude of the wafer W such that the surface of the wafer W in the light irradiation area ES falls within the allowable focus range of the projection optical system 30. In addition, when the abnormal location specified in S13 is included in the measurement target location, the control unit 60 sets the target attitude of the wafer W without using the measurement result of the abnormal location by the first measurement unit. Ask.

  For example, it is assumed that a target attitude of the wafer W when the measurement target locations TP11 to TP13 enter the light irradiation area ES is determined. In this case, in S13, the measurement target location TP11 is specified as an abnormal location. Therefore, the control unit 60 obtains the target posture of the wafer W based on the measurement results of the measurement target locations TP12 to TP13 by the first measurement unit without using the measurement result of the measurement target location TP11 by the first measurement unit. At this time, the control unit 60 calculates the target attitude of the wafer W based on the average value of the measurement results of the first measurement unit and the second measurement unit for each of the measurement target locations TP12 to TP13. You may. In this case, the target attitude of the wafer W can be more accurately obtained by the averaging effect.

  Here, when obtaining the target posture of the wafer W in S15, the control unit 60 may use the surface height of the abnormal location estimated from the measurement target location different from the abnormal location. For example, the control unit 60 determines the abnormal location (TP11) based on the measurement target locations (TP21, TP31) other than the abnormal location among the plurality of measurement target locations (TP11, TP21, TP31) arranged along the scanning direction. E) Estimate the surface height. Specifically, the average value of the surface heights measured by the second measurement unit for the measurement target locations TP21 and TP31 can be estimated as the surface height of the abnormal location TP11. Thereby, the control unit 60 obtains the target attitude of the wafer W based on the estimated value of the surface height of the abnormal location TP11 and the actual measurement of the surface height of the measurement target locations TP12 to TP13 by the first measurement unit. be able to.

  When obtaining the target posture of the wafer W in S15, the control unit 60 may use the surface height of the abnormal portion estimated from another wafer (second substrate) that has already been exposed. For example, the control unit estimates the surface height of the abnormal location based on the measurement result of the first measurement unit at the measurement location having the same substrate position as the abnormal location (TP11) among the other substrates. At this time, the surface height measured by the first measurement unit for the measurement target location of the other wafer having the same substrate position as the abnormal location may be estimated as the surface height of the abnormal location TP11. Thereby, the control unit 60 obtains the target attitude of the wafer W based on the estimated value of the surface height of the abnormal location TP11 and the actual measurement of the surface height of the measurement target locations TP12 to TP13 by the first measurement unit. be able to.

  In S16, the control unit 60 starts irradiating the light irradiation area ES with light, and starts scanning exposure of the shot area SR. At this time, the control unit 60 performs the scanning exposure of the shot region SR while controlling the attitude of the wafer W based on the target attitude determined in S15. For example, the control unit 60 controls the attitude of the wafer W so that the target attitude determined in S15 is at the timing when the measurement target locations TP11 to TP13 enter the light irradiation area ES. At this time, the control unit 60 may cause the area measuring units (MP3 to MP5) to measure the surface heights of the measurement target locations TP11 to TP13. The measurement of the surface height by the area measuring unit is performed for the purpose of confirming whether or not the surface of the wafer W in the light irradiation area ES is within the focus allowable range of the projection optical system 30. Not used for control.

  In S17, the control unit 60 determines whether to end the scanning exposure of the shot region SR. The control unit 60 performs the measurement by the above-described second measurement unit, the measurement by the first measurement unit, and the light irradiation area for each of the plurality of measurement target locations arranged along the scanning direction of the wafer W. Is repeated. Then, it is determined that the scanning exposure of the shot region SR ends when the light irradiation region ES exits the shot region SR.

  As described above, the exposure apparatus 1 of the present embodiment specifies an abnormal location based on the measurement result of the second measurement unit, and determines the attitude of the wafer W when the light irradiation area ES is arranged by the first measurement. The control is performed without using the measurement result at the abnormal part by the unit. Accordingly, even if the scanning speed of the wafer W tends to increase, the determination as to whether or not the measurement result of the first measurement unit can be used for controlling the attitude of the wafer W is made until the light irradiation area ES is arranged. Therefore, the attitude control of the wafer W can be accurately performed.

  Here, in the present embodiment, an example in which the same measurement target portion on the wafer W is measured twice while scanning the wafer W by the first measurement unit and the second measurement unit of the focus tilt measurement unit 50 will be described. did. However, the present invention is not limited to this. For example, the same measurement target portion on the wafer W may be measured twice (a plurality of times) by the first measurement unit (or the second measurement unit). In this case, first, for each of the plurality of measurement target locations on the wafer W, the first measurement by the first measurement unit is performed while scanning the wafer W, and an abnormal location is specified based on the measurement result. Thereafter, for each of the plurality of measurement target locations on the wafer W, a second height measurement is performed by the first measurement unit while scanning the wafer W, and while controlling the attitude of the wafer W based on the measurement result, The scanning exposure of W is performed. In this scanning exposure, the attitude of the wafer W is controlled without using the measurement result of the abnormal part in the second measurement result by the first measurement unit.

<Second embodiment>
A second embodiment according to the present invention will be described. FIG. 6 is a diagram showing an overall configuration of an exposure apparatus 1 'of the present embodiment. The exposure apparatus 1 'of the present embodiment is different from the exposure apparatus 1 shown in FIG. 1 in that information when scanning exposure is performed for each of the plurality of shot regions SR (hereinafter, may be referred to as "wafer information"). (Storage medium such as a memory) for storing the same for each wafer W is further provided. The wafer information includes, for example, the measurement results of the focus tilt measurement unit 50 (first measurement unit and second measurement unit), the position of the measurement target location specified as the abnormal location, and the estimation of the surface height applied to the abnormal location. It may include information such as values. In the example shown in FIG. 6, wafer information sequentially acquired for each wafer W, such as wafer W1, wafer W2, wafer W3, wafer W4,..., Can be stored individually. Note that the configuration of the exposure apparatus 1 'of this embodiment other than the storage unit 80 is the same as that of the exposure apparatus 1 shown in FIG. 1, and a description thereof will be omitted here.

  For a plurality of wafers W managed in the same lot, exposure processing is performed under the same conditions such as arrangement of shot areas, semiconductor processes, exposure control, and the like. Therefore, the height information of the measurement target portion having the same position (substrate position) in the wafer W has the same tendency between the wafer W on which the exposure processing has been performed up to the previous time and the wafer W on which the exposure processing is to be performed. For example, in the wafer W3, “abnormality” tends to occur at a measurement target location having the same substrate position as the measurement target location specified as an abnormal location on the wafer W2 that has been subjected to the exposure processing before that. Therefore, in the present embodiment, the abnormal location on the wafer W3 that is performing the exposure processing is determined by the measurement result of the second measurement unit on the wafer W3 and the abnormal location on the wafer W3 that has already been subjected to the exposure processing. It is specified by comparing with the measurement result. The wafers W to be compared are preferably in the same lot.

  Next, the exposure processing in the exposure apparatus 1 'of the present embodiment will be described. The exposure processing of this embodiment basically inherits the contents described with reference to FIGS. 3 and 4 in the first embodiment, but the step of identifying an abnormal part in S13 of the flowchart shown in FIG. This is different from the exposure processing of the first embodiment. Also, here, the exposure processing has already been completed for the wafers W1 and W2 (that is, the wafer information of the wafers W1 and W2 has been stored in the storage unit 80), and the exposure of the shot region SR of the wafer W3 has been completed. An example of performing the processing will be described.

  In S13 of the present embodiment, the control unit 60 determines the surface height of each measurement target location TP measured by the second measurement unit in the shot region SR of the wafer W3, and the surface height of each measurement target location TP in the wafer information of the wafer W2. Compare with height. The comparison can be performed between measurement target locations TP having the same substrate position in the wafer W3 that is currently subjected to the exposure processing and the wafer W2 that has already been subjected to the exposure processing. Thereby, the control unit 60 determines that the difference between the surface heights of the wafer W3 and the wafer W2 is equal to or less than the threshold value, corresponding to the measurement target location TP on the wafer W2 specified as the abnormal location based on the comparison result. The measurement target location TP on the wafer W3 can be specified as an abnormal location. The threshold can be set by a user via a user interface, for example.

  The control unit 60 compares the correlation of the measurement results of the second measurement unit at a plurality of measurement target locations (for example, TP11, TP21, TP31) arranged along the scanning direction between the wafer W3 and the wafer W2. You may compare. The control unit 60 may use, as the correlation, a difference between the measurement results between a plurality of measurement target locations arranged along the scanning direction, or a ratio of the measurement result between the plurality of measurement target locations. May be used. Also in this case, the control unit 60 corresponds to the measurement target location TP on the wafer W2 specified as the abnormal location based on the comparison result, and determines that the difference between the correlation between the wafer W3 and the wafer W2 is equal to or less than the threshold. The measurement target location TP on the wafer W3 can be specified as an abnormal location.

  Here, in the above example, the abnormal part of the wafer W3 is specified using the wafer information of the wafer W2, but the present invention is not limited thereto, and the abnormal part of the wafer W3 may be specified using the wafer information of the wafer W1. That is, the abnormal part of the wafer 3 may be specified using the wafer information of the wafer that has already been exposed. Further, when specifying an abnormal portion of the wafer W3, an average value of wafer information (for example, surface height of each measurement target portion) between the wafer W1 and the wafer W2 may be used. In this case, the influence of individual differences between wafers can be reduced, and the accuracy of specifying an abnormal portion can be increased.

  As described above, in the present embodiment, the abnormal portion on the wafer currently being subjected to the exposure processing is specified by comparing it with the wafer information acquired for the wafer W that has already been subjected to the exposure processing. With such a process, the attitude control of the wafer W can be performed with high accuracy, as in the first embodiment.

<Embodiment of Article Manufacturing Method>
The method for manufacturing an article according to the embodiment of the present invention is suitable for manufacturing an article such as a micro device such as a semiconductor device or an element having a fine structure. The method for manufacturing an article according to the present embodiment includes a step of forming a latent image pattern on a photosensitive agent applied to a substrate using the above-described exposure apparatus (a step of exposing the substrate), and a step of forming a latent image pattern in this step. Developing (working) the removed substrate. Further, such a manufacturing method includes other well-known steps (oxidation, film formation, vapor deposition, doping, planarization, etching, resist peeling, dicing, bonding, packaging, and the like). The method for manufacturing an article according to the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article as compared with the conventional method.

  The preferred embodiments of the present invention have been described above. However, it is needless to say that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the gist.

1: exposure apparatus, 10: illumination apparatus, 25: reticle stage, 30: projection optical system, 45: wafer stage, 50: focus tilt measuring unit, 60: control unit

Claims (11)

An exposure apparatus that exposes the substrate by moving a light irradiation area on the substrate while scanning the substrate,
During the scanning of the substrate, a first measurement for sequentially measuring the height of each of a plurality of measurement target locations arranged on the substrate along a scanning direction before each measurement target location enters the light irradiation area. Department and
During the scanning of the substrate, a second measurement unit that sequentially measures the height of each of the plurality of measurement target locations before the measurement by the first measurement unit is performed,
A control unit that controls a posture of the substrate during scanning of the substrate, based on a measurement result of the first measurement unit;
Including
The control unit specifies an abnormal location from among the plurality of measurement target locations based on a measurement result of each measurement target location by the second measurement unit, and measures a measurement result of the first measurement unit at the abnormal location. An exposure apparatus configured to control the attitude of the substrate without using the light source.   2. The exposure apparatus according to claim 1, wherein the control unit specifies the abnormal location based on a correlation between measurement results of the plurality of measurement target locations by the second measurement unit. 3.   3. The exposure apparatus according to claim 2, wherein the control unit obtains, as the correlation, a difference between measurement results of the plurality of measurement target locations at the second measurement unit. 4.   3. The exposure apparatus according to claim 2, wherein the control unit obtains, as the correlation, a ratio of a measurement result obtained by the second measurement unit at the plurality of measurement target locations.   The control unit specifies the abnormal location based on a comparison between the measurement result of the second measurement unit on the substrate and the measurement result of the second measurement unit on the substrate that has already been exposed. The exposure apparatus according to claim 1, wherein:   The control unit estimates the height of the abnormal location based on the measurement result of the second measuring unit for a location different from the abnormal location among the plurality of measurement target locations, and estimates the estimated abnormal location. The exposure apparatus according to claim 1, wherein an attitude of the substrate is controlled based on a height.   The control unit estimates the average value of the measurement results of the second measurement unit for a location different from the abnormal location among the plurality of measurement target locations, as the height of the abnormal location, The exposure apparatus according to claim 6, wherein   The control unit estimates the height of the abnormal portion based on the measurement result of the first measurement unit for a portion having the same substrate position as the abnormal portion in the substrate that has already been exposed, and estimates the height. The exposure apparatus according to claim 1, wherein an attitude of the substrate is controlled based on a height of the abnormal portion. An exposure apparatus that performs scanning exposure of a substrate,
A measurement unit that measures the height of each of the plurality of measurement target locations arranged on the substrate twice,
A control unit that controls the posture of the substrate based on a second measurement result by the measurement unit;
Including
The measurement unit specifies an abnormal location from among the plurality of measurement target locations based on a first measurement result by the measurement unit, and determines a measurement result of the abnormal location in a second measurement result by the measurement unit. An exposure apparatus configured to control the attitude of the substrate without using the light source. Exposing a substrate using the exposure apparatus according to any one of claims 1 to 9,
Developing the substrate that has been exposed in the step,
An article manufacturing method, comprising manufacturing an article from the developed substrate. An exposure method for exposing the substrate by moving the light irradiation area on the substrate while scanning the substrate,
During the scanning of the substrate, a first step of sequentially measuring the height of each of a plurality of measurement target locations arranged on the substrate along a scanning direction,
A second step of sequentially measuring the height of each of the plurality of measurement target locations during the scanning of the substrate after the measurement in the first step;
A third step of controlling the posture of the substrate in the light irradiation area based on the measurement result in the second step;
Including
In the third step, an abnormal point is specified from the plurality of measurement target points based on the measurement result of each measurement target point in the first step, and the measurement result in the second step at the abnormal point is determined. Controlling the attitude of the substrate without using the method.

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