KR102520864B1 - Exposure apparatus, exposure method, and method of manufacturing article - Google Patents

Abstract

An advantageous technique for controlling the posture of a substrate with high precision in scanning exposure of the substrate is provided.
An exposure apparatus that exposes the substrate by moving a light irradiation area on the substrate while scanning the substrate, while scanning the substrate, measures the height of each of a plurality of measurement target points arranged on the substrate along the scanning direction, respectively. a first measuring unit that sequentially measures the height of each of the plurality of measurement target locations during scanning of the substrate; a second measurement unit configured to perform measurement, and a control unit configured to control an attitude of the substrate during scanning of the substrate based on a measurement result by the first measurement unit, wherein the control unit includes: each measurement target by the second measurement unit; Based on the measurement result of the location, an abnormal location is identified from among the plurality of measurement target locations, and the posture of the substrate is controlled without using the measurement result of the first measuring unit at the abnormal location.

Description

Exposure apparatus, exposure method, and article manufacturing method

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

As one of the devices used in a manufacturing process (lithography process) of semiconductor devices and the like, by scanning a substrate, a light irradiation area to which light from a projection optical system is irradiated is moved on a shot area of the substrate to perform scanning exposure of the shot area. There is an exposure device that does this. 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 within the light irradiation area enters the focus allowable range of the projection optical system. The attitude of the substrate is controlled (refer to Patent Document 1).

In addition, in an exposure apparatus, a level difference may occur on a board|substrate by the adhesion of a foreign material etc., for example. In this case, if the posture of the substrate is controlled based on the measurement result of the level difference, defocus may occur in a part of the substrate, making it difficult to form a pattern on the substrate with high precision. Patent Literature 2 discloses that when there is measurement data exceeding a predetermined allowable value among measurement data obtained by predictive measurement, the measurement data is excluded and the height of the substrate is adjusted.

Japanese Unexamined Patent Publication No. 9-45608 Japanese Unexamined Patent Publication No. 2003-115454

In the exposure apparatus, in order to improve the throughput, it is desired to increase the scanning speed of the substrate, and the period from the predictive measurement to the arrangement of the light irradiation area tends to be shortened. Therefore, as described in Patent Literature 2, as a method for determining whether or not the measurement data itself can be used for adjusting the height of the substrate based on the measurement data obtained as predictive measurement, the judgment period is short and the height adjustment of the substrate is performed. It may be difficult to follow the scan of the substrate.

Accordingly, an object of the present invention is to provide an advantageous technique for controlling the posture of a substrate with high precision 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 exposes a substrate by moving a light irradiation area on the substrate while scanning the substrate, and during scanning of the substrate, along the scanning direction. a first measuring unit that sequentially measures the height of each of a plurality of measurement target points arranged on the substrate before each measurement target point enters the light irradiation area; and each of the plurality of measurement target points during scanning of the substrate a second measurement unit that sequentially measures the height of the height of the substrate before measurement by the first measurement unit; wherein the control unit identifies 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 the first measurement unit at the abnormal location It is characterized in that the posture of the substrate is controlled without using the measurement result of .

Other objects or other aspects of the present invention will be clarified by preferred embodiments described below with reference to the accompanying drawings.

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

1 is a diagram showing the overall configuration of an exposure apparatus according to a first embodiment.
2 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.
3 is a diagram showing a flowchart of exposure processing in the first embodiment.
4 is a diagram showing the positional relationship of a shot area, a plurality of measurement points by a focus tilt measurement unit, and a light irradiation area over time.
5 is a diagram for explaining processing for specifying an abnormal location.
6 is a diagram showing the overall configuration of an exposure apparatus according to a second embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, with reference to an accompanying drawing, preferred embodiment of this invention is described. In each drawing, the same reference numerals are given to the same members and elements, and overlapping descriptions are omitted. In addition, "measurement point" used in the following embodiment is defined as each element of a plurality of measurement marks in a measurement location in particular.

<First Embodiment>

[Configuration of Exposure Device]

A first embodiment according to the present invention will be described. 1 is a diagram showing the overall configuration of an exposure apparatus 1 of the present embodiment. In Fig. 1, an exposure apparatus 1 scans a substrate to move a light irradiation area where light from a projection optical system is irradiated onto a shot area of the substrate, and scans and exposes the shot area. It is a device. Such an exposure apparatus 1 is also called a scanning exposure apparatus or a scanner, and can transfer a circuit pattern formed on an original plate onto a substrate by performing scanning exposure of a shot region. In this embodiment, the original plate is, for example, a reticle R made of quartz, and a circuit pattern to be transferred is formed in each shot region of the substrate. In addition, the substrate is a wafer W coated with photoresist, and for example, a single crystal silicon substrate or the like can be used.

The exposure apparatus 1 includes an illumination apparatus 10, a reticle stage 25 that can hold and move a reticle R, a projection optical system 30, a wafer stage 45 that can hold and move a wafer W, It may include a focus tilt measurement unit 50, an alignment detection unit 70, and a control unit 60. The control unit 60 is constituted by, for example, a computer having a CPU or a memory, and is electrically connected to each unit in the device to collectively control the operation of the entire device.

The lighting device 10 includes a light source unit 12 and an illumination optical system 14, and illuminates a part of the reticle R on which the 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 laser light with a wavelength of about 248 nm or an ArF excimer laser that emits laser light with a wavelength of about 193 nm. In addition, the light source unit 12 is not limited to these excimer lasers, and may include an F2 laser that emits laser light with a wavelength of about 157 nm, an EUV (Extreme Ultra Violet) light source that emits light with a wavelength of 20 nm or less, and the like. do.

The illumination optical system 14 is an optical system that illuminates the reticle R using light flux emitted from the light source unit 12, and illuminates a part of the reticle R by shaping the light flux into a predetermined slit light optimal for exposure. The illumination optical system 14 includes a lens, a mirror, an optical integrator, and a diaphragm. For example, a condenser lens, a fly-eye lens, an aperture diaphragm, 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 and off-axis light. The optical integrator includes an integrator formed by overlapping a fly-eye lens or two sets of cylindrical lens array (or lenticular lens) plates, but it may be substituted with an optical rod or a diffraction element.

The reticle stage 25 may include a reticle chuck for holding the reticle R and a drive mechanism for driving the reticle R together with the reticle chuck. This driving mechanism is composed of, for example, a linear motor or the like, and can drive the reticle R in the X-axis direction, Y-axis direction, Z-axis direction, and rotational directions of each axis. Therefore, the reticle stage 25 can drive the reticle R in the Y-direction, which is the scanning direction, during scanning exposure of the wafer W. Also, 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 holding the wafer W and a driving mechanism that drives the wafer W together with the wafer chuck. This driving mechanism is constituted by, for example, a linear motor or the like, and can drive the wafer W in the X-axis direction, Y-axis direction, Z-axis direction, and rotational direction of each axis. Therefore, the wafer stage 45 can drive the wafer W in the Y-direction, which is the scanning direction, during scanning exposure of the wafer W. Also, 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 an image of the light flux from the object surface onto an image plane, and forms (projects) a pattern of a part of the reticle R illuminated by the illumination optical system 14 onto the wafer W at a predetermined projection magnification. can do. The area on the wafer W to which the light from the projection optical system 30 is irradiated is sometimes referred to as a "light irradiation area". Further, the alignment detection unit 70 detects marks on the wafer W, and obtains the arrangement (position) of each shot region on the wafer W. In the example shown in FIG. 1 , the off-axis method detects the mark on the wafer W without passing through the projection optical system 30, but TTL (Through The Lens) method may be configured.

In the exposure apparatus 1 structured as described above, the reticle R and the wafer W are disposed at optically nearly conjugate positions via the projection optical system 30 (the object plane and the image plane of the projection optical system 30), respectively. The control unit 60 relatively synchronously scans the reticle R and the wafer W by the reticle stage 25 and the wafer stage 45 at a speed ratio according to the projection magnification of the projection optical system 30, thereby converting the pattern of the reticle R to the wafer W. You can fight on top. And, by sequentially repeating such scanning exposure for each of a plurality of shot regions in the wafer W while moving the wafer stage 45 stepwise, the exposure process in one wafer W can be completed. .

[Configuration of focus tilt measurement unit]

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

FIG. 2 is a diagram showing the positional relationship between the shot area SR of the wafer W, a plurality of measurement points MP by the focus tilt measurement unit 50, and the light irradiation area ES. The measurement point MP is a position on the wafer W where dot-shaped measurement light is projected by the projector 52 and the surface height of the wafer W is measured. can move Also, arrows F and R in the figure indicate scanning directions 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 the surface height in the light irradiation area ES, a first measurement unit that measures the surface height prior to arrangement of the light irradiation area ES, and measurement by the first measurement unit. Prior to this, a second measurement unit for measuring the surface height may be included. In the example shown in FIG. 2 , the area measurement unit measures the surface height of the wafer W at measurement points MP3 to MP5 in the light irradiation area ES. The first measurement unit, also called a prediction measurement unit, measures the surface height of the wafer W at measurement points MP6 to MP8 or measurement points MP12 to MP14 separated from the light irradiation area ES by a distance Lp1. The second measurement unit, also called a prediction measurement unit, measures the surface height of the wafer W at measurement points MP9 to MP11 or measurement points MP15 to MP17 separated from the light irradiation area ES by a distance Lp2. The relationship between the distance Lp1 and the distance Lp2 is Lp1<Lp2.

Here, measurement points MP3 to MP5 may be spaced apart from each other in a direction different from the scanning direction of the wafer W (eg, a direction perpendicular to the scanning direction (X direction)). The same applies to each set of measurement points MP6 to MP8, measurement points MP9 to MP11, measurement points MP12 to MP14, and measurement points MP15 to MP17, and the measurement points are spaced apart from each other in a direction crossing the scanning direction of the wafer W. Also, MP3, MP6, MP9, MP12 and MP15 can be arranged at almost the same X coordinate position. Similarly, MP4, MP7, MP10, MP13, and MP16 may be located at substantially the same X-coordinate positions, and MP5, MP8, MP11, MP14, and MP17 may be located at substantially the same X-coordinate positions. In addition, although 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, the number of measurement points arranged in the different direction is not limited to three, but is two or more. Four or more may be sufficient.

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

[About scanning exposure]

In the exposure apparatus 1 structured as described above, while scanning the wafer W during the scanning exposure of the shot region SR, the surface height of the wafer W is measured by the focus tilt measurement unit 50 prior to the arrangement of the light irradiation region ES. (Predictive 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 a scanning exposure of the shot area SR, shortening the period from the prediction measurement to the arrangement of the light irradiation area ER reduces the influence of changes in the environment over time, such as atmospheric pressure fluctuations and temperature fluctuations, during the scanning exposure. harder to get Therefore, in the exposure apparatus 1 of the present embodiment, during the scanning exposure of the shot region SR, the measurement result at the first measurement unit (measurement points MP6 to MP8 or measurement points 12 to 14) of the focus tilt measurement unit 50 The posture of the wafer W is controlled based on .

By the way, in an exposure apparatus, a level difference may arise in the wafer W, for example, when a foreign material (particle) etc. adheres on the wafer W. In this case, if the posture of the wafer W is controlled based on the result of measuring the level difference by the focus tilt measuring unit 50, defocus is caused in a part of the wafer W, and the pattern of the reticle R is transferred onto the wafer W with high precision. It can be difficult to do. Therefore, in the exposure apparatus, it is determined whether or not the measurement result of the first measurement unit of the focus tilt measurement unit 50 can be used for posture control of the wafer W, and the measurement result determined to be unusable is not used and the posture control of the wafer W is performed. It is preferable to do

However, it is desired for the exposure apparatus to increase the scanning speed of the wafer W to improve the throughput, and from the first measurement unit of the focus tilt measurement unit 50 to perform the prediction measurement until the light irradiation area ES is arranged. The period tends to be shorter. Under such a situation, if the determination of whether or not the measurement result in the first measuring unit can be used for controlling the posture of the wafer W is made based on the measurement result in the first measuring unit, the judgment period is short and the posture of the wafer W It may become difficult to follow the control to the scanning of the wafer W.

Therefore, in the exposure apparatus 1 of the present embodiment, an abnormal location having an abnormality is specified from among a plurality of measurement target locations set on the wafer W based on the measurement result in the second measurement unit of the focus tilt measurement unit 50. Then, the posture of the wafer W when the light irradiation area ES is disposed is controlled without using the result of measurement at the abnormal location by the first measurement unit of the focus tilt measurement unit 50 . 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. In addition, "abnormality" can be defined as a locally specific value of the surface height measured by the focus tilt measuring unit 50 due to the attachment of a foreign object or the like with respect to other measurement target locations.

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

In the shot region SR, as shown in FIG. 4(a) , a plurality of measurement target location TPs whose surface heights are to be measured by the focus tilt measurement unit 50 are set (arranged). Measurement target locations TP11 to TP13 are measurement target locations where the surface height is first measured by the focus tilt measurement unit 50 when the wafer W is scanned in the direction of arrow F in the drawing. Measurement target points TP11 to TP13 may be arranged apart from each other along a direction different from the scanning direction so as to correspond to positions of a plurality (three) measurement points MP arranged along a direction different from the scanning direction (X-axis direction). . Further, the measurement target locations TP21 to TP23 may be set to be measured next to the measurement target locations TP11 to TP13, and the measurement target locations TP31 to TP33 may be set to be measured next to the measurement target locations TP21 to TP23.

Here, in the present embodiment, in the scanning direction F of the wafer W, the distance between the first measurement unit (measurement points MP6 to MP8) and the second measurement unit (measurement point MP9 to MP11) is the measurement target location TP11 to TP13 and the measurement target location TP31 to TP33. In addition, in this embodiment, in order to make the explanation easy to understand, an example of measuring the surface height at measurement target points TP11 to TP33 is described, and in FIG. 4, measurement target points other than measurement target points TP11 to TP33 are shown was omitted. However, in reality, 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 processing similar to that of the measurement target locations TP11 to TP33 is repeated. can

In S11, the controller 60 starts scanning 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, while scanning the wafer W, the control unit 60 causes the second measurement unit to measure the surface heights of the measurement target locations TP11 to TP13 at the timing when the second measurement unit is disposed at the measurement target locations TP11 to TP13 (FIG. 4 of (b)). Further, while continuing to scan the wafer W, the control unit 60 causes the second measurement unit to measure the surface heights of the measurement target locations TP21 to TP23 at the timing when the second measurement unit is disposed at the measurement target locations TP21 to TP23 (FIG. 4 of (c)). Similarly, while continuing to scan the wafer W, the control unit 60 causes the second measurement unit to measure the surface heights 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.

In S13, the control unit 60 specifies an abnormal location having an abnormality based on the measurement results in the second measurement unit (measurement points MP9 to MP11). In the example shown in Fig. 4, the control unit 60 specifies an abnormal location from among measurement target locations TP11 to TP33. For example, the control unit 60 obtains the correlation of measurement results in a plurality of measurement target locations (for example, TP11, TP21, and TP31) arranged along the scanning direction, so that the correlation exceeds the allowable range, A measurement target location that exists can be specified as an abnormal location. As the correlation, the control unit 60 may obtain a difference in measurement results between a plurality of measurement target points arranged along the scanning direction, or may obtain a ratio of measurement results between the plurality of measurement target points. Further, the permissible range is set based on depth of focus (DOF), pattern line width, exposure lighting mode, and the like, and may be set by the user through a user interface, for example.

5 is a diagram for explaining specific processing for specifying an abnormal location among a plurality of measurement target locations. Here, an example in which a difference in measurement results between measurement target points TP11, TP21, and TP31 arranged along the scanning direction is obtained as a correlation, and an abnormal point is specified from the difference will be described. The top view of FIG. 5 shows the surface heights measured at measurement target locations TP11, TP21, and TP31, and the bottom view of FIG. 5 shows the difference between measurement target locations TP11, TP21, and TP31. In the drawing, ΔZ12 is the difference in surface height between measurement target locations TP11 and TP21, ΔZ23 is the difference in surface height between measurement target locations TP21 and TP31, and ΔZ31 is the surface between measurement target locations TP31 and TP11 Each represents a difference in height.

As shown in Fig. 5 (a), 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 location. On the other hand, as shown in (b) of FIG. 5 , 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. (specific) can. Further, as shown in (c) of FIG. 5 , 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 processing is also performed for a set of measurement target locations TP12, TP22, and TP32 and a set of measurement target locations TP13, TP23, and TP33, so that the abnormal location can be specified for each set. Here, in the example shown in FIG. 4 , it is assumed that the measurement target location TP11 indicated by a ▲ mark is specified 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, while scanning the wafer W, 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 disposed at the measurement target locations TP11 to TP13 (FIG. 4 of (d)). Similarly, while continuing to scan the wafer W, the control unit 60 causes the first measurement unit to measure the surface heights 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 (FIG. 4 of (e)).

In S15, the control unit 60 determines, based on the result of measuring the surface height of the measurement target location by the first measurement units MP6 to MP8, the wafer W when each measurement target location enters (places) the light irradiation area ES. Determine (calculate) the target posture of At this time, the control unit 60 may determine the target posture 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 obtains the target posture of the wafer W without using the measurement result of the abnormal location by the first measurement unit.

For example, it is assumed that the target posture of the wafer W when the measurement target locations TP11 to TP13 enter the light irradiation area ES is obtained. In this case, in S13, the measurement target location TP11 is identified as an abnormal location. Therefore, the control unit 60 does not use the measurement results of the measurement target location TP11 by the first measurement unit, but based on the measurement results of the measurement target locations TP12 to TP13 by the first measurement unit, the target posture of the wafer W is obtained. At this time, the control unit 60 may obtain the target posture of the wafer W based on the average of the measurement results in the first measurement unit and the measurement results in the second measurement unit for each of the measurement target points TP12 to TP13. In this case, the target posture of the wafer W can be obtained with higher precision due to the averaging effect.

Here, when the controller 60 obtains the target posture of the wafer W in S15, it may use the surface height of the abnormal location estimated from a measurement target location different from the abnormal location. For example, the controller 60 determines the abnormal location TP11 based on the measurement target locations TP21 and TP31 other than the abnormal location among the plurality of measurement target locations TP11, TP21, and TP31 arranged along the scanning direction. Estimate the surface height of 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. Accordingly, the control unit 60 can obtain the target posture of the wafer W based on the estimated value of the surface height of the abnormal location TP11 and the measured value of the surface height of the measurement target locations TP12 to TP13 by the first measurement unit.

Further, when the controller 60 obtains the target posture of the wafer W in S15, it may use the surface height of the abnormal portion estimated from another wafer (second substrate) that has already been exposed. For example, the controller estimates the surface height of the abnormal location based on the measurement result by the first measurement unit in 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 measuring 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. Accordingly, the control unit 60 can obtain the target posture of the wafer W based on the estimated value of the surface height of the abnormal location TP11 and the measured value of the surface height of the measurement target locations TP12 to TP13 by the first measurement unit.

In S16, the controller 60 starts irradiation of light to the light irradiation area ES, and starts scanning exposure of the shot area SR. At this time, the controller 60 performs scanning exposure of the shot region SR while controlling the posture of the wafer W based on the target posture determined in S15. For example, the control unit 60 controls the posture of the wafer W so that it becomes the target posture determined in S15 at the timing when the measurement target points TP11 to TP13 enter the light irradiation area ES. In addition, at this time, the control unit 60 may have the area measurement units MP3 to MP5 measure the surface heights of the measurement target locations TP11 to TP13. The measurement of the surface height by this area measurement unit is performed for the purpose of confirming whether the surface of the wafer W in the light irradiation area ES is within the allowable focus range of the projection optical system 30, and is not used for posture control of the wafer W. don't

In S17, the controller 60 determines whether to end the scanning exposure of the shot region SR. The control unit 60 repeatedly performs the above-described measurement in the second measurement unit, measurement in the first measurement unit, and exposure in the light irradiation area for each of a plurality of measurement target locations arranged along the scanning direction of the wafer W. . Further, it is determined that scanning exposure of the shot region SR is to be ended when the light irradiation region ES passes through the shot region SR.

As described above, the exposure apparatus 1 of the present embodiment identifies an abnormal location based on the measurement result in the second measurement unit, and determines the posture of the wafer W when the light irradiation area ES is arranged in the first measurement unit. control without using the measurement result at the abnormal location. As a result, even if the scanning speed of the wafer W tends to be increased, it is possible to determine whether or not the measurement result in the first measuring unit can be used for posture control of the wafer W until the light irradiation area ES is disposed, and the wafer W posture control can be performed with high precision.

Here, in the present embodiment, an example in which the same measurement target location 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, it is not limited thereto, and for example, the same measurement target location on the wafer W may be measured twice (plural times) by the first measurement unit (or the second measurement unit). In this case, first, a first height measurement is performed by the first measurement unit while scanning the wafer W for each of a plurality of measurement target locations on the wafer W, and an abnormal location is specified based on the measurement result. After that, for each of a plurality of measurement target locations on the wafer W, the second height measurement by the first measurement unit is performed while scanning the wafer W, and the posture of the wafer W is controlled based on the measurement result. W scanning exposure is performed. In this scanning exposure, the posture of the wafer W is controlled without using the measurement result of the abnormal part among the second measurement results by the first measurement unit.

<Second Embodiment>

A second embodiment according to the present invention will be described. 6 is a diagram showing the overall configuration of exposure apparatus 1' of the present embodiment. Compared to the exposure apparatus 1 shown in FIG. 1 , the exposure apparatus 1' of the present embodiment provides information when scanning exposure is performed for each of a plurality of shot regions SR (hereinafter referred to as "wafer information"). A storage unit 80 (storage medium such as a memory) for storing each wafer W is further provided. Wafer information includes, for example, information such as measurement results from the focus tilt measurement unit 50 (first measurement unit, second measurement unit), the position of a specific measurement target location as an abnormal location, and an estimated value of the surface height applied to the abnormal location. can do. 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 individually stored. In addition, since the structure other than the storage part 80 in exposure apparatus 1' of this embodiment is the same as that of exposure apparatus 1 shown in FIG. 1, description regarding the said structure is abbreviate|omitted here.

For a plurality of wafers W managed in the same lot, exposure processing is performed under the same conditions of arrangement of shot regions, semiconductor process, exposure control, and the like. Therefore, the height information of the measurement target location having the same position (substrate position) in the same wafer tends to be the same between the wafer W previously subjected to exposure processing and the wafer W subjected to subsequent exposure processing. For example, in the wafer W3, "anomaly" tends to occur in a measurement target location having the same substrate position as the specified measurement target location and the abnormal location in the wafer W2 previously subjected to the exposure process. Therefore, in the present embodiment, the abnormal location in the wafer W3 undergoing the exposure process is determined by the measurement result of the second measuring unit in the wafer W3 and the second measurement result in the wafer W to which the exposure process has already been performed. It is specified by comparing measurement results in the measuring unit. The wafer W to be compared is preferably from the same lot.

Next, exposure processing in the exposure apparatus 1' of the present embodiment will be described. The exposure processing of the present embodiment basically follows the contents described with reference to Figs. 3 and 4 in the first embodiment, but the step of specifying the abnormal location in S13 of the flowchart shown in Fig. 3 is the first embodiment. It is different from the exposure treatment of In addition, here, the exposure processing has already been completed for the wafer W1 and the wafer W2 (that is, the wafer information of the wafer W1 and the wafer W2 is stored in the storage unit 80), and the exposure processing of the shot area SR of the wafer W3 An example of doing this 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 each measurement target location TP in the wafer information of the wafer W2 Compare the surface heights of The comparison can be made between the measurement target location TPs having the same substrate position in the wafer W3 currently undergoing exposure processing and the wafer W2 already undergoing exposure processing. As a result, the controller 60 determines, based on the comparison result, a wafer W3 corresponding to the measurement target location TP on the wafer W2 identified as the abnormal location and for which the difference in surface height between the wafer W3 and the wafer W2 is equal to or less than the threshold value. The above measurement target location TP can be specified as an abnormal location. The threshold may be set by a user through a user interface, for example.

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

Here, in the above example, the abnormal location of the wafer W3 is specified using the wafer information of the wafer W2, but it is not limited thereto, and the abnormal location of the wafer W3 may be specified using the wafer information of the wafer W1. That is, the abnormal location of the wafer W3 may be specified using the wafer information of the wafer on which the exposure process has already been performed. In addition, when specifying the abnormal location of the wafer W3, an average value of wafer information (eg, surface height of each measurement target location) in the wafer W1 and the wafer W2 may be used. In this case, it is possible to reduce the influence of individual differences between wafers and increase the accuracy of identifying an abnormal location.

As described above, in the present embodiment, an abnormal location on the wafer currently undergoing exposure processing is identified by comparing it with wafer information obtained for the wafer W on which exposure processing has already been performed. Even with such a process, as in the first embodiment, the attitude of the wafer W can be controlled with high precision.

<Embodiment of the manufacturing method of an article>

The method for manufacturing an article according to an 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 microstructure, for example. The method for manufacturing an article of the present embodiment includes a step of forming a latent image pattern on a photosensitive agent applied to a substrate using the exposure device (step of exposing the substrate), and developing (processing) the substrate on which the latent image pattern is formed in this step. ), including the process of In addition, such a manufacturing method includes other known processes (oxidation, film formation, vapor deposition, doping, planarization, etching, resist removal, dicing, bonding, packaging, etc.). Compared with conventional methods, the method for manufacturing an article of the present embodiment is advantageous in at least one of performance, quality, productivity, and production cost of the article.

As mentioned above, although the preferable embodiment of this invention was described, this invention is not limited to these embodiment, of course, various deformation|transformation and change are possible within the scope of the summary.

1: exposure device
10: lighting device
25: reticle stage
30: projection optical system
45: wafer stage
50: focus tilt measurement unit
60: control unit

Claims (11)

An exposure apparatus that exposes a substrate by moving a light irradiation area on the substrate while scanning the substrate,
a first measurement unit that sequentially measures heights of a plurality of measurement target locations arranged on the substrate along the scanning direction during scanning of the substrate 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 points during scanning of the substrate before measurements are performed at the first measuring unit;
a control unit for controlling an attitude of the substrate during scanning of the substrate based on a measurement result by the first measurement unit;
The control unit identifies an abnormal location from among the plurality of measurement target locations based on the measurement results of each measurement target location by the second measurement unit, and uses the measurement result by the first measurement unit at the abnormal location. An exposure apparatus characterized in that the posture of the substrate is controlled without According to claim 1,
The exposure apparatus, characterized in that the control unit specifies the abnormal location based on a correlation of measurement results of the second measurement unit in the plurality of measurement target locations. According to claim 2,
An exposure apparatus characterized in that a difference between measurement results at the second measurement unit for two arbitrary locations selected from among the plurality of measurement target locations is obtained as the correlation. According to claim 2,
The exposure apparatus, characterized in that the control unit obtains, as the correlation, a ratio of a measurement result at the second measurement unit to two arbitrary locations selected from among the plurality of measurement target locations. According to claim 1,
The controller identifies the abnormal location based on a comparison between a measurement result of the second measurement unit on the substrate and a measurement result of the second measurement unit on a substrate that has already been exposed. , exposure device. According to claim 1,
The control unit estimates the height of the abnormal location based on the measurement result of the second measurement unit for the remaining locations other than the abnormal location among the plurality of measurement target locations, and based on the estimated height of the abnormal location, An exposure apparatus characterized by controlling the posture of the substrate. According to claim 6,
The exposure apparatus, characterized in that the controller estimates an average value of measurement results by the second measurement unit for the remaining locations excluding the abnormal location among the plurality of measurement target locations as the height of the abnormal location. According to claim 1,
The controller estimates the height of the abnormal location based on the measurement result of the first measuring unit for a portion having the same substrate position as the abnormal location among the substrates that have already been exposed, and estimates the height of the abnormal location. An exposure apparatus characterized in that the attitude of the substrate is controlled based on the An exposure apparatus that performs scanning exposure of a substrate,
a measurement unit that measures each height of a plurality of measurement target points arranged on the substrate twice;
A control unit for controlling the posture of the substrate based on a second measurement result by the measurement unit;
The measurement unit identifies an abnormal location from among the plurality of measurement target locations based on the first measurement result by the measurement unit, and does not use the measurement result of the abnormal location among the second measurement results by the measurement unit. An exposure apparatus characterized by controlling the posture of the substrate. A step of exposing a substrate using the exposure apparatus according to any one of claims 1 to 9;
a step of developing the substrate exposed in the step;
A method of manufacturing an article, characterized in that an article is manufactured from the developed substrate. An exposure method in which a substrate is exposed by moving a light irradiation area on the substrate while scanning the substrate;
A first step of sequentially measuring the height of each of a plurality of measurement target points arranged on the substrate along the scanning direction during scanning of the substrate;
a second step of sequentially measuring the height of each of the plurality of measurement target points during 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 region based on the measurement result in the second step;
In the third step, based on the measurement result of each measurement target point in the first step, an abnormal location is identified from among the plurality of measurement target locations, and the measurement result in the second step at the abnormal location is determined. An exposure method characterized in that the posture of the substrate is controlled without using.

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