JP2003115437A - Aligner and exposure method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aligner and an exposure method for improving focus accuracy and throughput. SOLUTION: Marks 21 (L2), 31 (R2) for focus measurement are arranged larger than observation effective regions 20 (L1), 30 (R1) of left and right scopes for observation so that the left and right scopes for observation in the first alignment optical system can simultaneously observe the left and right marks 21 (L2), 31 (R2) for focus measurement in a stage reference planar mirror 12. While the wafer stage is being moved in the direction of the light axis of the projection optical system, reflection light from the marks 21 (L2), 31 (R2) for focus measurement is detected simultaneously by the right and left scopes for observation in the first alignment optical system, at least either the focus position of the projection optical system or the inclination of the water stage is detected based on the quantity of light and/or the change in contrast.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus and an exposure method for manufacturing devices such as semiconductor circuit elements (IC, LSI, VLSI, etc.), and more particularly to baseline measurement and focus measurement technology in a projection type exposure apparatus. It is a thing.

[0002]

2. Description of the Related Art FIG. 14 is a schematic diagram showing a projection exposure apparatus having an automatic baseline measuring function and an automatic focus measuring function in a conventional example. In the figure, the light emitted from the exposure light source 901 is guided by the switching mirror 902 to the illumination optical system 903 when the pattern on the original plate such as the reticle is transferred and exposed on the substrate such as the wafer, and the exposure light is exposed. When observed by, the light is guided to the fiber 931. The illumination optical system 903 irradiates the entire surface of the reticle.

A reticle 904 is held on a reticle stage 905. The circuit pattern on the reticle 904 is projected by the projection lens (exposure lens) 906 so that x
Wafer 90 on yz stage (wafer stage) 907
8 is reduced to 1/5, 1/4, or 1/10 to form an image, and exposure is performed. In FIG. 14, a reference plane mirror 909 is arranged at a position adjacent to the wafer 908 so that the upper surface of the wafer 908 and the mirror surface are substantially aligned with each other. The reference plane mirror 909 is provided with a stage reference mark shown in FIG.

FIG. 15 is an explanatory view of an autofocus measurement mark and a baseline measurement mark in a conventional example. FIG. 15A is a focus measurement mark that enables measurement in the X direction and the Y direction, and FIG. Is a baseline measurement mark on the reticle or the reticle reference plate, (c) is a baseline measurement mark on the reference plane mirror, (d) is an image image formed on the position sensor,
(E) and (f) respectively show the baseline measurement marks on the reference plane mirror.

The xyz stage 907 is a projection lens 90.
It is possible to move in the optical axis direction (Z) of 6 and in the plane (X, Y) orthogonal to this direction, and of course, it is possible to rotate around the optical axis.

In a so-called scanning type exposure apparatus which transfers and exposes a pattern on a reticle 904 onto a wafer 908 while synchronously scanning the reticle stage 905 and the xyz stage 907, the reticle stage 905 includes a projection lens 90.
It is also possible to rotate in the plane (X, Y) orthogonal to the optical axis direction of 6 and around the optical axis.

In the figure, elements 910 and 911 form an off-axis autofocus optical system.
Reference numeral 910 denotes a light projecting optical system (autofocus incident system), and the light flux which is non-exposure light emitted from the light projecting optical system 910 is a point on the reference plane mirror 909 (or the wafer 9
The light is focused on the upper surface 08) and reflected. The light flux reflected by the reference plane mirror 909 enters a detection optical system (autofocus light receiving system) 911.

Although omitted in FIG. 14, the detection optical system 911 is used.
A position detecting light receiving element is arranged inside, and the position detecting light receiving element and the reflection point of the light flux on the reference plane mirror 909 are arranged to be conjugate. Reference plane mirror 9
The displacement of the reduction projection lens 906 of the 09 in the optical axis direction is
It is measured as the positional deviation of the incident light beam on the position detecting light receiving element in the detection optical system 911.

The positional deviation of the reference plane mirror 909 measured by the detection optical system 911 from a predetermined reference plane is
It is transmitted to the autofocus control system 921. The autofocus control system 921 gives a command for movement in the Z direction or in the X and Y tilt directions to the drive system 922 that drives the xyz stage 907 to which the reference plane mirror 909 is fixed. In addition, when the TTL defocus position is detected by the detection optical system 930 described later, the autofocus control system 9
Reference numeral 21 drives the reference plane mirror 909 up and down in the optical axis direction (Z direction) of the projection lens 906 in the vicinity of a predetermined reference position. Further, the position control of the wafer 908 at the time of exposure is also performed by the autofocus control system 921.

Next, the components for detecting the focus state of the surface of the wafer 908 and driving the xyz stage 907 based on the signal to detect the focus position of the projection lens 906 will be described.

930 is a TTR (Through The Reticle)
Detection optical system of each of the elements 931 and 932 described later,
It has 933, 934, and 935. Fiber 931
The illumination light flux having substantially the same wavelength as the exposure light emitted from passes through the half mirror 932, and the objective lens 933 and the mirror 93
The light is focused in the vicinity of the reticle 904 via the lens 4. Reticle 9
Although not shown in the drawing, a transmission portion (window opening portion) of a predetermined size is provided on the position 04 outside the actual element region.

Although not shown in the figure, the reticle stage 905 is provided with a reticle reference plate on which marks for the purpose of reticle alignment measurement are arranged.

After passing through the window cutout or the reticle reference plate, the illumination light beam is condensed on the reference plane mirror 909 via the projection lens 906. On the reference flat mirror 909, the focus measurement mark shown in FIG. 15A is fixed. Then, the reflected light from the reference plane mirror 909 returns to the original optical path, and the projection lens 906, the window cutout portion (or reticle reference plate), and the mirror 93 are sequentially arranged.
4, reflected by the half mirror 932 through the objective lens 933, and then incident on the position sensor 935.

The focus measurement mark in FIG. 15A is composed of vertical and horizontal line-and-space having a predetermined line width. The position sensor 935 described above may be a one-dimensional array sensor or a two-dimensional sensor represented by a CCD. That is, the position sensor 935 is the same as that of FIG.
Corresponding to the focus measurement mark of 5 (a), a one-dimensional array sensor is sufficient if focus detection of only one direction pattern (vertical line or horizontal line) is sufficient, and bidirectional pattern (simultaneous vertical line and horizontal line). If the focus detection is required, a two-dimensional array sensor is used.

In the conventional example, the reference plane mirror surface 909 is used as the projection lens 90 in order to obtain the optimum focus surface.
Shaking in the direction of the optical axis of 6. At that time, the position sensor 935
Correspondingly, in the above, information in which the focus state of the focus measurement mark in FIG. 15A has changed is obtained.

Which kind of focus information is used as a signal is not particularly limited. For example, the fact that the light intensity contrast of the stage reference mark image is highest at the best focus position and lowered at the defocus position may be used, or the differential value of the light profile of the stage reference mark image (corresponding to the tilt angle). Can be evaluated. The image signal analysis circuit 940 performs these signal processes.

Next, components for performing baseline detection will be described. 930 is the TTR as described above.
It is a detection optical system, and its constituent elements are as described above. At the time of baseline detection, the illumination light flux emitted from the fiber 931 illuminates the reticle 904 shown in FIG. 15B or the baseline measurement mark on the reticle reference plate. The illumination light flux passes through the baseline measurement mark in FIG. 15B, and then is focused on the reference plane mirror 909 via the projection lens 906. Reference plane mirror 9
The baseline measurement mark of FIG. 15C is fixedly provided on 09. Then, the reflected light from the reference plane mirror 909 returns to the original optical path, and the projection lens 906, the reticle 904 or the reticle reference plate, and the mirror 93 are sequentially arranged.
4, reflected by the half mirror 932 through the objective lens 933, and then incident on the position sensor 935.

FIG. 15D is an image image formed on the position sensor 935. On the position sensor 935,
Both the baseline measurement mark on the reticle 904 or the reticle reference plate and the baseline measurement mark on the reference plane mirror 909 will be visible at the same time.

Reference numeral 950 denotes a TTL (Through The Lens) off-axis detection optical system, which includes elements 951 and 9 to be described later.
52, 953, 954. The illumination light flux having a different wavelength from the exposure light emitted from the light source 951 is reflected by the half mirror 95.
2 and the projection lens 906 through the mirror 953, and the light is focused on the reference plane mirror 909. On the reference plane mirror 909, the baseline measurement marks shown in FIGS. 15E and 15F are fixed. Then, the reflected light from the reference plane mirror 909 returns to the original optical path, is sequentially reflected by the projection lens 906, the mirror 953, and the half mirror 952 and is incident on the position sensor 954. Although not shown, similar measurement can be performed by using an off-axis detection optical system that can measure the wafer surface or the stage reference mark without passing through the projection optical system.

The baseline measuring marks in FIGS. 15E and 15F are composed of vertical and horizontal line-and-space having a predetermined line width. The baseline measurement mark corresponding to the off-axis detection optical system that does not pass the projection optical system is a multi-mark for vertical measurement and horizontal measurement.

Although not shown in FIG. 14, the TTL off-axis detection optical system 950 for baseline measurement is composed of two independent optical systems for vertical direction measurement and horizontal direction measurement. In the baseline measurement, the above-described baseline measurement mark is measured by the TTR detection optical system and the TTL detection optical system, and the deviation amount of each mark is measured to perform calibration. Further, the above-mentioned off-axis detection optical system that does not pass through the projection optical system is composed of an optical system capable of simultaneously measuring the vertical direction and the horizontal direction.

[0022]

In recent years, semiconductor devices, L
Due to the demand for finer patterns and higher integration of SI elements, VLSI elements, etc., an image forming (projecting) optical system having a high resolving power has been required in a projection exposure apparatus. Along with this, the NA of the image forming optical system has increased, and as a result, the depth of focus of the image forming optical system has become shallower. Further, in the projection exposure apparatus, since a small amount and a wide variety of products such as ASIC are becoming mainstream, improvement in throughput is required.

In the conventional autofocus measurement, since only one focus measurement mark fixed on the reference plane mirror is arranged, two TTR detections on the left and right sides are taken into consideration in consideration of the measurement time of the autofocus measurement. Of the optical systems, only one of the detection optical systems was used for measurement.

Further, in the conventional example, by using only one conventional focus measurement mark, autofocus measurement is performed by each of the two left and right TTR detection systems, and the average value is used as the result of the autofocus measurement. A method of improving the measurement accuracy has also been proposed.

However, according to this method, measurement cannot be performed unless the focus measurement mark is driven to a position corresponding to the field of view of the TTR detection optical system, so that the wafer stage must be driven wastefully, and therefore the throughput is increased. Was in decline.

Further, in the conventional arrangement of the stage reference marks, when performing the autofocus measurement after the baseline measurement, the measurement is not possible unless the observation scope of the TTR detection optical system and the wafer stage are driven. Since it was possible, the throughput was lowered.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an exposure apparatus and an exposure method that improve focus accuracy and throughput.

[0028]

In order to solve the above problems, an exposure apparatus according to the present invention is a projection device for projecting and exposing a pattern of an original plate mounted on an original plate stage onto a substrate mounted on a substrate stage. An optical system and a first alignment light are applied to a first stage reference mark fixed on the original stage and / or the substrate stage, and reflected light from the first stage reference mark is passed through the projection optical system. And a first alignment optical system for detecting the first stage reference mark of each of the observation scopes in order to simultaneously observe the first stage reference mark using each of the observation scopes. It is characterized in that it is arranged larger than the mark detection range. Here, it is preferable that the first alignment light has substantially the same wavelength as the exposure illumination light, and the plurality of observation scopes of the first alignment optical system are arranged in the X direction and / or the Y direction.
It is possible to provide two left and right observation scopes that can be driven in any direction.

In the present invention, the exposure apparatus irradiates the second stage reference mark fixed on the substrate stage with the second alignment light having a wavelength different from that of the exposure illumination light, and the second stage reference mark. It is possible to further include a second alignment optical system that detects reflected light from the mark, and an observation scope of the first alignment optical system,
In order to perform mark observation simultaneously using the observation scope of the second alignment optical system, the first stage reference mark and the second stage reference mark may be arranged within the mark detection range of each observation scope. preferable. Further, the exposure apparatus simultaneously measures the first stage reference mark and the second reference mark by the first alignment optical system and the second alignment optical system, and performs a baseline measurement based on each measurement value. It is preferable to further have a measuring means.

Further, in the present invention, the first stage reference mark is a mark continuous in the X direction,
And / or it is preferable that they are arranged side by side in the Y direction.

In order to solve the above problems, the exposure method of the present invention is a projection optical system for projecting and exposing a pattern of an original plate mounted on an original plate stage onto a substrate mounted on a substrate stage, and a first optical system. The alignment light is applied to the first stage reference mark fixed on the original stage and / or the substrate stage, and the first stage reference mark is applied via the projection optical system.
A first alignment optical system that detects reflected light from a stage reference mark by a plurality of observation scopes, and simultaneously moves the substrate stage in the optical axis direction of the projection optical system while simultaneously using the first stage in each of the observation scopes. A detection step of observing or detecting the reflected light from the reference mark and detecting at least one of the focus position of the projection optical system and the inclination of the substrate stage based on the change in the light amount and / or the contrast. To do.
Here, it is preferable that the first alignment light has substantially the same wavelength as that of the illumination light for exposure, and the plurality of observation scopes of the first alignment optical system are left and right capable of being driven in the X direction and / or the Y direction. It is possible to provide as two observation scopes.

In the present invention, the second alignment light having a central wavelength different from that of the exposure illumination light is applied to the second stage reference mark fixed on the substrate stage via the projection optical system, It is possible to further include a second alignment optical system that detects reflected light from the second stage reference mark via the projection optical system, and in the detecting step, the position of the substrate stage at the time of baseline measurement is determined. The observation scope of the first alignment optical system is not moved and only the observation scope of the first alignment optical system is driven, and then the substrate stage is moved in the optical axis direction of the projection optical system at the same time with the observation scopes of the first alignment optical system. The focus position of the projection optical system and the substrate stage based on the change in the amount and / or the contrast of the reflected light from the one-stage reference mark It is preferable that detects at least one of inclination.

Further, in the present invention, the first stage reference mark is a mark continuous in the X direction,
And / or it is preferable that they are arranged side by side in the Y direction.

[0034]

Embodiments of the present invention will now be described in detail with reference to the drawings. (First Embodiment) FIG. 1 is a schematic view showing a main part of a projection exposure apparatus according to an embodiment of the present invention. In FIG.
Reference numeral 11 (A1) is a wafer chuck. A wafer, which is a photosensitive substrate, is adsorbed and held on the wafer chuck 11. Reference numeral 12 (B1) is a stage reference plane mirror.

FIG. 2 is a schematic view of a stage reference plane mirror in which an autofocus measurement mark is arranged in one embodiment of the present invention. In the present embodiment, as shown in FIG. 2, focus measurement marks are arranged on the stage reference plane mirror 12. The mark shape of the focus measurement mark is not particularly limited. The mark may be in only one direction (X direction or Y direction) or may be in two directions (X direction and Y direction).

In FIG. 2, 20 (L1) and 30 (R
1) shows the effective observation area in the left observation scope and the right observation scope of the TTR detection optical system, respectively. Here, the observation effective region is a region in which the focus measurement mark can be observed when the observation scope is driven in the X direction or the Y direction.

21 (L2) and 31 (R2) are T
The focus measurement marks corresponding to the left observation scope and the right observation scope of the TR detection optical system are shown. As can be seen from FIG. 2, the focus measurement marks are long arranged on the entire observation effective area in the X drive direction of the left and right TTR detection optical systems.

As described above, by disposing the focus measurement marks on the entire observation effective area in the X drive direction of the left and right TTR detection optical systems, the X of the left and right TTR detection optical systems can be obtained.
Even if the directional positions are driven to different positions, it is possible to observe the focus measurement marks simultaneously on the left and right by the left and right TTR detection optical systems without driving the stage reference plane mirror (wafer stage). Since the X-direction positions of the left and right TTR detection optical systems can be measured at different positions, the focus measurement can be performed in accordance with the left and right positions of the light shielding plate that can be driven vertically and horizontally. Is possible.

FIG. 3 is an enlarged view of the stage reference plane mirror in this embodiment. The focus measurement mark is
One kind of mark having a certain line width and line spacing may be used, or as shown in FIG. 3, several kinds of marks having different line widths or line intervals may be arranged in the X and Y directions.

As shown in FIG. 2, when the focus measurement marks are arranged on the stage reference plane mirror as shown in FIG.
It is a figure which shows the process flow at the time of implementing autofocus measurement with a TTR detection optical system on either side.

In step S1, the left and right TTR detection optical systems are driven to the observation position. At this time, the Y-direction coordinates of the left and right TTR detection optical systems are driven corresponding to the Y-direction arrangement of the left and right focus measurement marks arranged on the stage reference plane mirror.

At this time, the line widths and line intervals of the marks to be measured need to be driven so that the left and right focus measurement marks are the same. Left and right TTR detection optical system X
The directional coordinates may be arranged anywhere.

In FIG. 4, in step S2, the wafer stage is driven in the optical axis direction of the projection optical system. In step S3, the TTR detection optical system on the left side measures the focus measurement mark. In step S4, T on the right side
The focus detection mark is measured by the TR detection optical system. In step S5, the optimum focus plane is detected by both the left and right TTR detection optical systems. When the optimum focus planes are detected by both the left and right TTR detection optical systems in step S5 (in the case of Y), the measurement ends.
If the optimum focus surface is not detected in step S5 (in the case of N), steps S2 to S5 are repeated until the optimum focus surface is detected by both the left and right TTR detection optical systems.

In this embodiment, it is possible to detect the focus position of the projection optical system and / or the tilt of the wafer stage based on the change in the amount of reflected light from the mark and / or the contrast.

(Second Embodiment) FIG. 5 is a schematic view of a stage reference plane mirror in which an autofocus measurement mark according to the second embodiment is arranged. In this embodiment, as shown in FIG. 5, focus measurement marks are arranged on the stage reference plane mirror 12.

In FIG. 5, 20 (L1) and 30 (R
1) shows the effective observation area in the left observation scope and the right observation scope of the TTR detection optical system, respectively. In addition, 51 (L21) to 54 (L24) and 56 (R2
Reference numerals 1) to 59 (R24) denote focus measurement marks corresponding to the left observation scope and the right observation scope of the TTR detection optical system, respectively. As can be seen from FIG. 5, the focus measurement mark is located at the position corresponding to the effective observation area in the Y drive direction of the left and right TTR detection optical systems.
They are arranged side by side.

Focus measurement marks 51 (L21) to 5
4 (L24) and 56 (R21) to 59 (R24) may be one kind of mark having a certain line width and line spacing, or may be a line width or line spacing in the Y direction as shown in FIG. You may arrange several different marks.

As described above, the focus measurement marks are arranged side by side in the Y direction at the positions corresponding to the effective observation areas in the Y drive direction of the left and right TTR detection optical systems, so that the Y directions of the left and right TTR detection optical systems are arranged. Even when the position is driven to a different position, it is possible to observe the focus measurement marks simultaneously on the left and right by the left and right TTR detection optical systems without driving the stage reference plane mirror (wafer stage).

FIG. 4 shows a processing flow for performing autofocus measurement by the left and right TTR detection optical systems when the focus measurement marks are arranged on the stage reference plane mirror.
Is the same as the processing flow of.

In step S1, the left and right TTR detection optical systems are driven to the observation position. At this time, the Y-direction coordinates of the left and right TTR detection optical systems are set on the stage reference plane mirror in Y
It is driven to a position corresponding to the left and right focus measurement marks arranged side by side. It is also possible to obtain the tilt in the Y direction by driving the left and right TTR detection optical systems to positions separated in the Y direction and measuring.

At this time, it is necessary to drive the marks to be measured so that the line widths and line intervals of the marks are the same for the left and right focus measurement marks. Further, the coordinates of the left and right TTR detection optical systems in the X direction may be driven anywhere. Furthermore, the operation from step S2 to step S5 is as described above.

(Third Embodiment) FIG. 6 is a schematic view of a stage reference plane mirror in which a baseline measurement mark is arranged in the third embodiment. In this embodiment, as shown in FIG. 6, a baseline measurement mark is arranged on the stage reference plane mirror.

In FIG. 6, 20 (L1) and 30 (R
1), 20 '(L1) and 30' (R1) are TT respectively
The observation effective area in the left observation scope and the right observation scope of the R detection optical system is shown. In addition, 61 (L3
1) and 62 (R31), 61 '(L31) and 62' (R
31) shows the baseline measurement marks corresponding to the left observation scope and the right observation scope of the TTR detection optical system, respectively.

In the figure, 61 (L31) and 62 (R3) are attached to the observation scopes of the left and right TTR detection optical systems.
Only 1), 61 '(L31) and 62' (R31) have the baseline measurement marks, but match the baseline measurement mark on the reticle or the baseline measurement mark on the reticle reference plate. Thus, a plurality of marks may be arranged.

Reference numeral 65 (T1) indicates an effective observation area in the observation scope of the TTL detection optical system. Reference numerals 66 (Tx1) and 67 (Ty1) denote the X-direction measurement mark and the Y-direction measurement mark of the TTL detection optical system, respectively.

61 (L31), 62 (R31), 66 (Tx
1), and 67 (Ty1), or 61 '(L31), 6
2 ′ (R31), 66 (Tx1), and 67 (Ty1) are the observation scopes and TT on the left and right of the TTR detection optical system, respectively.
It is an observation scope in the X and Y directions of the L detection optical system, and is arranged so that it can be observed all at the same time without driving the wafer stage.

(Fourth Embodiment) FIG. 7 is a schematic view of a stage reference plane mirror in which a baseline measurement mark and an autofocus measurement mark are arranged in the fourth embodiment. In this embodiment, as shown in FIG. 7, a baseline measurement mark and a focus measurement mark are arranged on the stage reference plane mirror.

In FIG. 7, 20 (L1) and 30 (R
1), 20 '(L1) and 30' (R1) are TT respectively
The observation effective area in the left observation scope and the right observation scope of the R detection optical system is shown. In addition, 51 (L2
1) and 56 (R21), 51 '(L21) and 56' (R
Reference numerals 21) respectively show focus measurement marks corresponding to the left observation scope and the right observation scope of the TTR detection optical system. In addition, 61 (L31) and 62
Reference numerals (R31), 61 '(L31) and 62' (R31) indicate baseline measurement marks corresponding to the left observation scope and the right observation scope of the TTR detection optical system, respectively.

In the figure, reference numeral 65 (T1) indicates an effective observation area in the observation scope of the TTL detection optical system.
Reference numerals 66 (Tx1) and 67 (Ty1) denote the X-direction measurement mark and the Y-direction measurement mark of the TTL detection optical system.

FIG. 8 shows a processing flow when the autofocus measurement is executed after the baseline measurement is completed in this embodiment.

In FIG. 8, first, baseline measurement and baseline correction are performed. In step S11, the left and right TTR detection optical systems are driven to the observation position. Next, in step S12, the baseline measurement mark (wafer stage) is driven to a position where the marks can be observed by each observation scope of the TTR detection optical system and the TTL detection optical system.

Thereafter, in step S13, the left and right TTs are
The R detection optical system and the TTL detection optical systems in the X and Y directions simultaneously measure the marks observed by each observation scope. For the next measurement, in step S14, the baseline measurement mark (wafer stage) is driven in XY for the purpose of reducing the quantization error to shift the mark.

In step S15, the amount of deviation between the marks on the reticle or reticle reference plate and the mark on the stage reference plane mirror measured by the left and right TTR detection optical systems in step S13 and the TTL detection optical system in the X and Y directions are measured. The amount of mark deviation in the XY directions is calculated.

In step S16, it is determined whether or not the baseline measurement is completed. If the measurement is not completed (in the case of N), step S1 is executed until the baseline measurement is completed.
The processing from 3 to step S15 is repeated. After all the measurements are completed (Y in step S16), in step S17,
Perform baseline correction. Following the end of the baseline correction, autofocus measurement is performed.

In step S18, the position of the stage reference plane mirror (wafer stage) at the end of the baseline measurement is not moved, and the left and right TTR detection optical systems are driven to positions where the focus measurement marks can be observed. Next, in step S19, the stage reference plane mirror (wafer stage) is driven in the optical axis Z direction. When the focus measurement mark and the baseline measurement mark measured by the TTR detection optical system are the same mark, step S18 is omitted.

In step S20, after the driving of the wafer stage is completed, the left and right TTR detection optical systems simultaneously measure the focus measurement marks. In step S21, it is checked whether the optimum focus planes have been detected by both the left and right TTR detection optical systems (Y / N). In the case of N in step S21, the processes of steps S19 to S21 are repeated until the optimum focus planes are detected by both the left and right TTR detection optical systems. If Y in step S21, step S2
Measurement ends at 2.

As described above, in FIG.
Although the auto focus measurement is performed using the TR detection optical system, the focus measurement may be performed using one of the left and right TTR detection optical systems as in the past.

Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and improvements and changes can be made without departing from the scope of the claims. . For example, although the TTL detection optical system is the detection optical system in the X and Y directions in the third and fourth embodiments, the TTL detection optical system is a scope capable of detecting marks in a two-dimensional direction such as CCD. May be replaced with
Further, instead of the TTL detection optical system, an Off-Axis detection optical system that does not use a projection optical system may be used.

(Embodiment of Semiconductor Production System) Next, a device such as a semiconductor (I
An example of a production system of a semiconductor chip such as C or LSI, a liquid crystal panel, a CCD, a thin film magnetic head, a micromachine, etc.) will be described. This is to carry out maintenance services such as troubleshooting of a manufacturing apparatus installed in a semiconductor manufacturing factory, periodic maintenance, or software provision using a computer network or the like outside the manufacturing factory.

FIG. 9 shows the whole system cut out from a certain angle. In the figure, 101 is a business office of a vendor (apparatus supplier) that provides a semiconductor device manufacturing apparatus. As an example of a manufacturing apparatus, a semiconductor manufacturing apparatus for various processes used in a semiconductor manufacturing factory, for example,
Pre-process equipment (lithography equipment such as exposure equipment, resist processing equipment, etching equipment, heat treatment equipment, film forming equipment,
Flattening equipment, etc.) and post-process equipment (assembling equipment, inspection equipment, etc.) are assumed. In the business office 101, a host management system 10 that provides a maintenance database for manufacturing equipment is provided.
8, a plurality of operation terminal computers 110, and a local area network (LAN) 109 that connects these to construct an intranet or the like. Host management system 1
08 is provided with a gateway for connecting the LAN 109 to the Internet 105, which is an external network of the office, and a security function for restricting access from the outside.

On the other hand, 102 to 104 are semiconductor manufacturers (semiconductor device manufacturers) as users of the manufacturing apparatus.
Manufacturing plant. The manufacturing factories 102 to 104 may be factories belonging to different makers or may be factories belonging to the same maker (for example, a pre-process factory, a post-process factory, etc.). In each of the factories 102 to 104, a plurality of manufacturing apparatuses 106, a local area network (LAN) 111 that connects them to construct an intranet, and a host as a monitoring apparatus that monitors the operating status of each manufacturing apparatus 106 are provided. A management system 107 is provided. The host management system 107 provided in each factory 102 to 104 includes a gateway for connecting the LAN 111 in each factory to the Internet 105 which is an external network of the factory. As a result, the host management system 108 on the vendor 101 side can be accessed from the LAN 111 of each factory via the Internet 105, and only the limited user is permitted to access by the security function of the host management system 108. Specifically, via the Internet 105,
The factory side notifies the vendor side of status information indicating the operating status of each manufacturing apparatus 106 (for example, a symptom of the manufacturing apparatus in which a trouble has occurred), and the response information corresponding to the notification (for example, an instruction for a troubleshooting method is given. Information to
It is possible to receive maintenance information such as countermeasure software and data), the latest software, and help information from the vendor side. A communication protocol (TCP / IP) generally used on the Internet is used for data communication between the factories 102 to 104 and the vendor 101 and data communication on the LAN 111 in each factory. In addition,
Instead of using the Internet as an external network outside the factory, it is also possible to use a leased line network (ISDN or the like) having high security without being accessed by a third party. Further, the host management system is not limited to one provided by a vendor, and a user may construct a database and place it on an external network to permit access from a plurality of factories of the user to the database.

Now, FIG. 10 is a conceptual diagram showing the entire system of this embodiment cut out from an angle different from that shown in FIG. In the above example, a plurality of user factories each provided with a manufacturing apparatus are connected to a management system of a vendor of the manufacturing apparatus via an external network, and production management of each factory or at least one unit is performed via the external network. Was used for data communication of information on the manufacturing equipment. On the other hand, in this example,
A factory equipped with manufacturing apparatuses of a plurality of vendors and a management system of a vendor of each of the plurality of manufacturing apparatuses are connected by an external network outside the factory to perform data communication of maintenance information of each manufacturing apparatus. In the figure, reference numeral 201 denotes a manufacturing plant of a manufacturing device user (semiconductor device manufacturing maker), and a manufacturing device for performing various processes on the manufacturing line of the factory, here an exposure device 202 and a resist processing device 20 as examples
3. The film forming processing device 204 is installed. Note that FIG.
In FIG. 0, only one manufacturing plant 201 is drawn, but in reality, a plurality of factories are similarly networked. Each device in the factory is connected by a LAN 206 to form an intranet or the like, and the host management system 205 manages the operation of the manufacturing line. On the other hand, the exposure apparatus manufacturer 210,
Resist processing equipment manufacturer 220, film deposition equipment manufacturer 230
Etc., each business office of the vendor (equipment supplier) is provided with host management systems 211, 221, 231 for performing remote maintenance of the supplied equipment, respectively. These are maintenance databases and gateways of external networks as described above. Equipped with. The host management system 205 that manages each device in the user's manufacturing factory and the vendor management systems 211, 221, and 231 of each device are connected by the external network 200 such as the Internet or a dedicated line network. In this system, if a trouble occurs in any of the series of manufacturing equipment on the manufacturing line, the operation of the manufacturing line is suspended, but the vendor of the equipment in trouble receives remote maintenance via the Internet 200. This enables quick response and minimizes production line downtime.

Each manufacturing apparatus installed in the semiconductor manufacturing factory has a display, a network interface, and a computer for executing the network access software and the apparatus operating software stored in the storage device. The storage device is a built-in memory, a hard disk, a network file server, or the like. The network access software includes a dedicated or general-purpose web browser and provides a user interface with a screen as shown in FIG. 11 on the display. The operator who manages the manufacturing apparatus in each factory refers to the screen and the manufacturing apparatus model (401), serial number (402), trouble subject (403), date of occurrence (404), urgency (40).
5), symptom (406), coping method (407), progress (40)
8) Input information such as the above into the input items on the screen. The input information is transmitted to the maintenance database via the Internet, and the appropriate maintenance information as a result is returned from the maintenance database and presented on the display. Further, the user interface provided by the web browser is further provided with a hyperlink function (410, 411, 4) as shown in the figure.
12) is realized, the operator can access more detailed information of each item, pull out the latest version of software to be used for the manufacturing equipment from the software library provided by the vendor, and use it as a guide for the factory operator. Help information) can be retrieved. Here, the maintenance information provided by the maintenance database includes the information about the present invention described above, and the software library also provides the latest software for implementing the present invention.

Next, a semiconductor device manufacturing process using the above-described production system will be described. 12
Shows a flow of the whole manufacturing process of the semiconductor device. In step 1 (circuit design), the circuit of the semiconductor device is designed. In step 2 (mask manufacturing), a mask having the designed circuit pattern is manufactured. On the other hand, in step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by the lithography technique using the mask and the wafer prepared above. The next step 5 (assembly) is called a post-process, which is a process of forming a semiconductor chip using the wafer manufactured in step 4, and an assembly process (dicing,
Assembling process such as bonding) and packaging process (chip encapsulation). In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test. A semiconductor device is completed through these processes and shipped (step 7). The front-end process and the back-end process are performed in separate dedicated factories, and maintenance is performed for each of these factories by the remote maintenance system described above. Also, between the front-end factory and the back-end factory,
Information and the like for production management and equipment maintenance are data-communicated via the Internet or a leased line network.

FIG. 13 shows a detailed flow of the wafer process. In step 11 (oxidation), the surface of the wafer is oxidized. In step 12 (CVD), an insulating film is formed on the wafer surface. In step 13 (electrode formation), electrodes are formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted in the wafer. In step 15 (resist processing), a photosensitive agent is applied to the wafer.
In step 16 (exposure), the circuit pattern of the mask is printed and exposed on the wafer by the exposure apparatus described above. In step 17 (development), the exposed wafer is developed. In step 18 (etching), parts other than the developed resist image are removed. In step 19 (resist stripping), the resist that is no longer needed after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer. Since the manufacturing equipment used in each process is maintained by the remote maintenance system described above, troubles can be prevented in advance, and even if troubles occur, quick recovery is possible, and Productivity can be improved.

[0076]

As described above, according to the present invention,
The following effects are achieved. (1) In autofocus measurement, the measurement accuracy is improved by obtaining the average of the measurement values of the left and right TTR detection optical systems. (2) In autofocus measurement, the throughput can be improved because the left and right TTR detection optical systems can simultaneously perform measurement without XY driving the wafer stage. (3) In the baseline measurement, since the mark measurement can be performed simultaneously by the left and right TTR detection optical systems and the X and Y TTL detection optical systems, the throughput is improved. (4) Since the autofocus measurement can be performed with the wafer stage position unchanged after the baseline measurement is completed, the throughput is improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a main part of a projection exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of a stage reference plane mirror on which an autofocus measurement mark is arranged according to an embodiment of the present invention.

FIG. 3 is an enlarged view of a stage reference plane mirror according to an embodiment of the present invention.

FIG. 4 is a diagram showing a processing flow when autofocus measurement is performed by the left and right TTR detection optical systems when focus measurement marks are arranged on a stage reference plane mirror in one embodiment of the present invention.

FIG. 5 is a schematic view of a stage reference plane mirror on which an autofocus measurement mark according to the second embodiment is arranged.

FIG. 6 is a schematic view of a stage reference plane mirror on which a baseline measurement mark is arranged in the third embodiment.

FIG. 7 is a schematic view of a stage reference plane mirror on which a baseline measurement mark and an autofocus measurement mark are arranged in the fourth embodiment.

FIG. 8 is a diagram showing a processing flow when autofocus measurement is executed after completion of baseline measurement in an embodiment of the present invention.

FIG. 9 is a conceptual view of a semiconductor device production system including an exposure apparatus according to an embodiment of the present invention as viewed from an angle.

FIG. 10 is a conceptual view of a semiconductor device production system including an exposure apparatus according to an embodiment of the present invention as viewed from another angle.

FIG. 11 is a diagram showing a specific example of a user interface in a semiconductor device production system including an exposure apparatus according to an embodiment of the present invention.

FIG. 12 is a diagram illustrating a flow of a device manufacturing process by the exposure apparatus according to the embodiment of the present invention.

FIG. 13 is a diagram illustrating a wafer process performed by the exposure apparatus according to the embodiment of the present invention.

FIG. 14 is a schematic diagram showing a projection exposure apparatus having an automatic baseline measurement function and an automatic focus measurement function in a conventional example.

FIG. 15 is an explanatory diagram of an autofocus measurement mark and a baseline measurement mark in a conventional example,
(A) is a focus measurement mark that enables measurement in the X and Y directions, (b) is a baseline measurement mark on the reticle or reticle reference plate, and (c) is a baseline measurement on a reference plane mirror. Mark, (d)
Is an image formed on the position sensor, (e),
(F) shows the baseline measurement marks on the reference plane mirror.

[Explanation of symbols]

11: Wafer chuck, 12: Stage reference plane mirror, 20, 20 ': Observation effective area 21, 51, 52, 53, 54 of the observation scope on the left side of the TTR detection optical system.
51 ': Focus measurement mark corresponding to the left observation scope of the TTR detection optical system, 30, 30': Observation effective area of the right observation scope of the TTR detection optical system, 31, 5
6, 57, 58, 59, 56 ': focus measurement marks corresponding to the observation scope on the right side of the TTR detection optical system, 6
1, 61 ': baseline measurement mark corresponding to the observation scope on the left side of the TTR detection optical system, 62, 62': T
Baseline measurement mark corresponding to the observation scope on the right side of the TR detection optical system, 65: effective observation area in the observation scope of the TTL detection optical system, 66: X of the TTL detection optical system
Direction measurement mark, 67: Y direction measurement mark of TTL detection optical system, 901: exposure light source, 902: switching mirror, 903: illumination optical system, 904: reticle, 905:
Reticle stage, 906: Projection lens, 907: xy
z stage, 908: wafer, 909: reference plane mirror, 910: autofocus entrance system, 911: autofocus exit system, 921: autofocus control system,
922: drive system, 930: TTR detection optical system, 93
1: fiber, 932, 952: half mirror, 93
3: objective lens, 934, 953: mirror, 935, 9
54: Position sensor, 940: Image signal analysis circuit, 95
0: TTL off-axis detection optical system, 951: light source.

Claims (16)

[Claims] 1. A projection optical system for projecting and exposing a pattern of an original placed on an original stage onto a substrate placed on a substrate stage, and a first alignment light on the original stage and / or the substrate stage. A first alignment optical system that irradiates a first stage reference mark fixed to the first stage reference mark and detects reflected light from the first stage reference mark through the projection optical system by a plurality of observation scopes. An exposure apparatus, wherein the first stage reference mark is arranged larger than a mark detection range of each of the observation scopes so that the first stage reference marks can be observed simultaneously using the observation scopes. 2. The exposure apparatus irradiates a second stage reference mark fixed on the substrate stage with a second alignment light having a wavelength different from that of the exposure illumination light, and outputs the second alignment reference mark from the second stage reference mark. A second alignment optical system for detecting reflected light is further provided, and the first stage is used for simultaneously performing mark observation using the observation scope of the first alignment optical system and the observation scope of the second alignment optical system. The exposure apparatus according to claim 1, wherein the reference mark and the second stage reference mark are arranged within a mark detection range of each of the observation scopes. 3. The exposure apparatus simultaneously measures the first stage reference mark and the second reference mark by the first alignment optical system and the second alignment optical system, and a baseline based on each measurement value. The exposure apparatus according to claim 2, further comprising a measuring unit that performs measurement. 4. The first stage reference mark is a mark continuous in the X direction.
The exposure apparatus according to any one of 1. 5. The first stage reference marks are arranged side by side in the Y direction.
The exposure apparatus according to any one of 1. 6. The exposure apparatus according to claim 1, further comprising a display, a network interface, and a computer that executes network software, and the exposure apparatus maintenance information is stored in a computer network. An exposure apparatus that enables data communication via the. 7. The network software is connected to an external network of a factory in which the exposure apparatus is installed and provides a user interface on the display for accessing a maintenance database provided by a vendor or a user of the exposure apparatus. 7. The exposure apparatus according to claim 6, which makes it possible to obtain information from the database via the external network. 8. A projection optical system for projecting and exposing a pattern of an original placed on an original stage onto a substrate placed on a substrate stage, and a first alignment light on the original stage and / or the substrate stage. A first alignment optical system for irradiating a first stage reference mark fixed to the first stage and detecting reflected light from the first stage reference mark through the projection optical system with a plurality of observation scopes. Simultaneously observing the reflected light from the first stage reference mark with each of the observation scopes while moving the stage in the optical axis direction of the projection optical system, and based on the change in the light quantity and / or contrast of the projection optical system, An exposure method comprising a detection step of detecting at least one of a focus position and an inclination of the substrate stage. 9. A second alignment light having a wavelength different from that of the illumination light for exposure is irradiated onto a second stage reference mark fixed on the substrate stage via the projection optical system, and then via the projection optical system. Further comprising a second alignment optical system for detecting the reflected light from the second stage reference mark, and in the detecting step, the position of the substrate stage during the baseline measurement is not moved, and the observation of the first alignment optical system is performed. Only the scopes are driven, and then the substrate stage is moved in the optical axis direction of the projection optical system, while the observation scopes of the first alignment optical system simultaneously perform the first observation.
The at least one of the focus position of the projection optical system and the inclination of the substrate stage is detected based on a change in the amount of reflected light from the stage reference mark and / or a change in contrast. Exposure method. 10. The exposure method according to claim 8, wherein the first stage reference mark is a mark continuous in the X direction. 11. The exposure method according to claim 8, wherein the first stage reference marks are arranged side by side in the Y direction. 12. A step of installing a manufacturing apparatus group for various processes including the exposure apparatus according to claim 1 in a semiconductor manufacturing factory, and a plurality of processes using the manufacturing apparatus group. And a step of manufacturing a semiconductor device. 13. Data communication of information relating to at least one of the manufacturing apparatus group between the step of connecting the manufacturing apparatus group by a local area network, and between the local area network and an external network outside the semiconductor manufacturing factory. The method for manufacturing a semiconductor device according to claim 12, further comprising: 14. A database provided by a vendor or a user of the exposure apparatus is accessed through the external network to obtain maintenance information of the manufacturing apparatus by data communication, or a semiconductor manufacturing factory different from the semiconductor manufacturing factory. 14. The semiconductor device manufacturing method according to claim 13, wherein production control is performed by performing data communication with the device via the external network. 15. A group of manufacturing apparatuses for various processes including the exposure apparatus according to claim 1, a local area network connecting the group of manufacturing apparatuses, and a local area network to outside the factory. A semiconductor manufacturing factory, which has a gateway that enables access to the external network, and enables data communication of information regarding at least one of the manufacturing apparatus groups. 16. The method according to claim 1, which is installed in a semiconductor manufacturing factory.
A method for maintaining an exposure apparatus according to any one of claims 1 to 7, wherein the vendor or user of the exposure apparatus provides a maintenance database connected to an external network of the semiconductor manufacturing factory, and the semiconductor manufacturing factory. A step of permitting access to the maintenance database from the inside via the external network; and a step of transmitting the maintenance information accumulated in the maintenance database to the semiconductor manufacturing factory side via the external network. Maintenance method for exposure equipment.