JP2000252201A - Surface position detecting method and apparatus, projection exposure method and apparatus using the same, and semiconductor device manufacturing method - Google Patents

Abstract

(57) Abstract: A method and apparatus for detecting a position of a surface, a method and an apparatus for projection exposure using the same, and a method for manufacturing a semiconductor device. To determine the difference between the step and the slope by recognizing the position of the step. SOLUTION: Position detection is repeated by changing a combination of groups in grouping of measurement points 1 to 9, and information on a step D on a substrate W is obtained based on position information for each group. Therefore, the combination of groups is changed. When there is no step between the measurement points in the group,
The tendency of the position information is remarkably different from the case where there is a step, and information such as the step position can be obtained. For example,
When there is no step between the measurement points in the group, the height positions of the measurement points in one group are almost the same in each group, and it can be recognized that the step is located between the groups.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for detecting a surface position used in, for example, an exposure step in semiconductor manufacturing, a projection exposure method and an apparatus using the same, and a semiconductor device manufacturing method.

[0002]

2. Description of the Related Art Conventionally, as an apparatus for detecting a surface position of an inspection object to obtain a focal position, for example, a focal position detecting apparatus used for an exposure apparatus, for example, Japanese Patent Application Laid-Open No. 58-113 is disclosed.
As disclosed in Japanese Patent Publication No. 706, a semiconductor wafer positioned at a position where a mask pattern is transferred by a projection optical system is irradiated with detection light from an oblique direction.
A so-called oblique incidence type focus position detecting device is used.

In this focus position detecting device, a surface of a semiconductor wafer is used as a surface to be inspected, and a slit-like pattern is formed on the surface to be inspected, and the longitudinal direction of the slit is a plane extending between incident light and reflected light, that is, perpendicular to the incident surface. Project in a direction that gives
The reflected light is re-imaged on a detecting means comprising a photoelectric conversion element so that an incident position of the reflected light on the detecting means can be detected.

In recent years, with the increasing integration of LSIs, exposure areas (shot areas) on a semiconductor wafer have been developed.
It is desired to transfer a fine pattern to the projection optical system, and in order to cope with this, the numerical aperture NA (Num
erical Aperture) is largely composed. However, since the depth of focus of the projection optical system is reduced by increasing the numerical aperture NA, it is desired that the exposure area be more accurately and reliably positioned at the focal position (within the depth of focus) of the projection optical system.

[0005] In addition, the size of the exposure area has been increased by the exposure apparatus, and printing has been performed to increase the exposure area of the LSI chip itself in one exposure, or a plurality of LSI chips have been exposed in one exposure. Is being burned. For this reason, it is desired to position the entire exposure region, which is increasing in size or the like, more accurately and reliably at the focal position (within the depth of focus) of the projection optical system. In response to such demands, in recent years, a multi-point focus detection device in which a plurality of measurement points are arranged in an exposure area on a wafer has been used. As a multi-point focus detecting device, for example, Japanese Patent Application Laid-Open
No. 275313 and Japanese Patent Application Laid-Open No. 2-198130.

However, in recent semiconductor device manufacturing, many complicated structures are stacked on a semiconductor wafer, and the flatness of the exposed surface on the semiconductor wafer tends to deteriorate. Therefore, for the process offset of the focal position, the optimum offset value has been calculated by actually performing test exposure and observing the exposed semiconductor wafer with an SEM or the like. Further, the leveling adjustment employs a method in which the output value of each sensor at a plurality of measurement points is adjusted to a least-squares approximation plane using a two-dimensional AF sensor.

[0007]

The above-mentioned conventional focus position detecting means does not cause a problem when the same product is mass-produced. However, obtaining the offset in this manner in each layer of the process has the disadvantage of requiring a great deal of labor and time. In the leveling operation of the two-dimensional AF sensor, as shown in FIG. 8A, the output values of the sensors at a plurality of measurement points on the semiconductor wafer W are adjusted to the least-squares approximation plane L. For this reason, on surfaces having different height positions due to the step D, the respective surface positions cannot be obtained, and the inclination and the step D cannot be distinguished. Even when there is no inclination component, as shown in FIG. There has been a problem that the peripheral portion of the shot is defocused due to the inclination.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and enables a surface position to be accurately detected and an appropriate offset or the like to be obtained even when there is a step. It is an object of the present invention to provide a surface position detecting method and apparatus capable of accurately discriminating a tilt and an inclination, a projection exposure method and apparatus using the same, and a semiconductor device manufacturing method.

[0009]

The present invention has the following features to attain the object mentioned above. In other words, the surface position detecting method according to claim 1 will be described with reference to FIGS. 1 to 7. The projection optical system on the substrate (W) surface to which the mask pattern is transferred via the projection optical system (PL) In the surface position detection method for detecting the position in the optical axis direction, a grouping step of dividing at least three measurement points on the substrate into at least two groups; and A detection step of detecting the position information in the optical axis direction, wherein the combination of the groups in the grouping step is changed to repeat the detection step, and the substrate is formed based on the position information for each group obtained in the detection step. A technique for obtaining information on the upper step (D) is employed.

Further, in the surface position detecting device according to the present invention, the surface for detecting the position of the projection optical system in the optical axis direction on the substrate (W) surface to which the mask pattern is transferred via the projection optical system (PL). A position detecting device configured to divide at least three measurement points on the substrate into at least two groups; and detecting position information in the optical axis direction in each group based on a measurement result of each measurement point. And a control unit (70b) for controlling the calculation unit and the detection unit. The control unit changes the combination of the groups by the calculation unit and changes the position information by the detection unit. A technique is employed in which detection is repeated and information on the step (D) on the substrate is obtained based on the position information for each group obtained by the detection unit.

In these surface position detecting methods and apparatuses,
The position detection is repeated by changing the combination of the groups in the grouping of the measurement points, and the step (D) on the substrate (W) is determined based on the position information for each group obtained by the position detection.
Since the information about the information is obtained, when the combination of the groups is changed and the grouping is performed according to the shape (arrangement) of the step, the tendency of the positional information between the groups is remarkably different. Information such as the step position can be obtained. For example, when there is no step between the measurement points in each group, the height position of the measurement points in one group is almost the same in each group, and there is a step between the groups at this time. Be recognized.

According to a fourth aspect of the present invention, there is provided a projection exposure method for projecting and exposing a pattern on a mask (R) onto a surface of a substrate (W) via a projection optical system (PL). A technology for performing the exposure by positioning the substrate with respect to the focal position of the projection optical system based on the step (D) information obtained by the surface position detection method according to any one of (1) to (3).

In the projection exposure apparatus according to the present invention,
A projection exposure apparatus that projects and exposes a pattern on a mask (R) onto a surface of a substrate (W) via a projection optical system (PL), and detects a surface position of the substrate with respect to a focal position of the projection optical system. A technology including the surface position detecting device (10) according to claim 6 is adopted. Further, in the method of manufacturing a semiconductor device according to the present invention, the method of manufacturing a semiconductor device includes a step of transferring a pattern of a mask (R) onto a substrate (W). A technique of transferring a pattern is employed.

In the projection exposure method and apparatus, and the semiconductor device manufacturing method, based on the step (D) information obtained by the above-described surface position detection method or apparatus (10),
Since the exposure is performed by positioning the substrate (W) with respect to the focal position of the projection optical system (PL), highly accurate exposure can be performed without defocusing even on the substrate surface having the step (D). .

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of a projection exposure method and apparatus using a surface position detection method and apparatus according to the present invention and a semiconductor device manufacturing method will be described below with reference to FIGS.

FIG. 1 shows a projection exposure apparatus 40 provided with an oblique incidence type multi-point focal position detection apparatus (surface position detection apparatus) 10 according to the present embodiment. The pattern of the reticle R is transferred onto the semiconductor wafer W as a mask by a scanning method. The projection exposure apparatus 40 includes an illumination system 60 including an exposure light source, a reticle stage RST holding a reticle R, a projection optical system PL, and a wafer stage W on which a semiconductor wafer W is mounted.
ST and the like.

The illumination system 60 includes an exposure light source and an illumination optical system (neither is shown). The illumination optical system includes a collimator lens, an illuminance uniforming optical system including an optical integrator such as a fly-eye lens or a rod-type integrator, a relay lens, a variable ND filter, a reticle blind, a relay lens, and the like. Is illuminated by the illumination light IL with uniform illuminance. Here, each of the driving units in the illumination system, that is, the variable ND filter, the reticle blind, and the like are controlled by the illumination control device 62 in accordance with an instruction from the main control device 70.

The reticle stage RST is arranged on a reticle base plate 64, and has a reticle R on its upper surface.
Is fixed, for example, by vacuum suction. Here, the reticle stage RST is positioned in a plane perpendicular to the optical axis of the illumination optical system (in the XY plane) for positioning the reticle R by a reticle stage driving unit (not shown) composed of a magnetic levitation type two-dimensional linear actuator. , And can be driven at a designated scanning speed in a predetermined scanning direction.

The position of reticle stage RST is always detected by reticle laser interferometer 66 with a resolution of, for example, about 0.5 to 1 nm. The position information of the reticle stage RST from the interferometer 66 is sent to the stage control device 69 and to the main control device 70 via the stage control device 69. The reticle stage RST is driven via a reticle stage driving unit (not shown) based on the position information.

The projection optical system PL is arranged below the reticle stage RST, and the direction of the optical axis AX is set to the Z-axis direction. Here, a predetermined projection magnification which is telecentric on both sides, for example, 1/5 (or 1 /). The reduction optical system having 4) is used. Therefore, when the illumination area IAR of the reticle R is illuminated by the illumination light IL from the illumination system 60, the illumination light IL passing through the reticle R causes
Through the projection optical system PL, a reduced image of the circuit pattern of the reticle R in the illumination area IAR is formed in the exposure area IA on the semiconductor wafer W whose surface is coated with a resist.

The wafer stage WST is arranged on a wafer base plate 67 arranged below the projection optical system PL, and a wafer holder 6 is mounted on the wafer stage WST.
8 are placed. The semiconductor wafer W is vacuum-sucked on the wafer holder 68 via a vacuum chuck (not shown). The wafer holder 68 is configured to be tiltable in an arbitrary direction with respect to the best image forming plane of the projection optical system PL and to be finely movable in the optical axis AX direction (Z direction) of the projection optical system PL by a driving unit (not shown). ing. The wafer holder 68 is also capable of rotating about the Z axis.

Here, wafer stage WST is driven in the two-dimensional directions of the X-axis and the Y-axis by wafer driving device 72 comprising a magnetic levitation type two-dimensional linear actuator. That is, the wafer stage WST moves not only in the scanning direction but also in a non-scanning direction perpendicular to the scanning direction so that a plurality of shot areas on the semiconductor wafer W can be positioned in the exposure area IA conjugate to the illumination area IAR. Step-and-repeat of an operation of scanning (scanning) exposure of each shot area on the semiconductor wafer W and an operation of moving to a scanning start position for exposure of the next shot. Perform a scan operation.

The position of wafer stage WST is always detected by wafer laser interferometer 74 with a resolution of, for example, about 0.5 to 1 nm. The measured value of the interferometer 74 is
Stage control device 69 and main control device 70 via this
The stage controller 69 drives the wafer stage WST via the wafer driving device 72 based on the position information of the wafer stage WST in response to an instruction from the main controller 70. On wafer stage WST, a reference plate FP on which a reference mark for baseline measurement and other reference marks are formed is arranged.

The operations of the illumination system 60, the reticle stage RST, the wafer stage WST and the like during scanning exposure are managed by the main controller 70 via the illumination controller 62, the stage controller 69 and the like. Further, in the projection exposure apparatus 40, an off-axis type alignment microscope ALG for detecting the position of an alignment mark (wafer mark) attached to each shot area on the semiconductor wafer W is provided on a side surface of the projection optical system PL. The measurement result of the alignment microscope ALG is provided to the main controller 7.
0 is supplied.

The reticle base plate 64, the wafer base plate 67, the projection optical system P
Main components such as L are held by the same main body frame, and the main body frame is horizontally held via an anti-vibration pad (not shown).

In the projection exposure apparatus 40, an irradiation optical system AF1 for supplying an image forming light beam (detection beam FB) for forming a plurality of slit images or pinhole images obliquely with respect to the optical axis AX direction, An oblique incidence type multi-point focal position detecting device (focal position detecting sensor, detecting unit) 10 including a light receiving optical system AF2 for receiving the respective reflected light beams of the image forming light beam on the surface of the semiconductor wafer W via slits.
Are fixed to a holding member (not shown) that supports the projection optical system PL. The position information on the wafer from the multipoint focus position detection device 10 is sent to the stage control device 69 via the main control device 70. The stage controller 69 drives the wafer holder 68 in the Z direction and the tilt direction based on the position information.

The multi-point focal position detecting device 10 is used to measure the height position or defocus of the semiconductor wafer W in the optical axis direction of the projection optical system PL at a plurality of locations within the projection field of view of the projection optical system PL. Measurement points are provided, and the focal position is detected based on these measurement points. In the irradiation optical system AF1 of the multipoint focal position detecting device 10, the resist applied on the semiconductor wafer W is irradiated on the slit plate 11 with a non-photosensitive detection beam FB as shown in FIG. The light that has passed through the slit of the slit plate 11 irradiates the semiconductor wafer W obliquely via the lens system 12, the mirror 13, the aperture 14, the projection objective lens 15, and the mirror 16. At this time, if the surface of the semiconductor wafer W is on the best image forming plane, an image of the slit of the slit plate 11 is formed on the surface of the semiconductor wafer W by the lens system 12 and the objective lens 15. The angle between the optical axis of the objective lens 15 and the surface of the semiconductor wafer is set to about 5 to 12.

Light beams of a plurality of slit images reflected by the semiconductor wafer W are received through a mirror 17, a light receiving objective lens 18, a lens system 19, a vibration mirror 20, and a parallel flat plate (plane parallel) 21 in the light receiving optical system AF2. Is re-imaged on the slit plate 22. The vibrating mirror 20 is
The slit image formed on the light receiving slit plate 22 is slightly vibrated in a direction perpendicular to the longitudinal direction. The parallel flat plate 21 shifts the relative relationship between the slit on the slit plate 22 and the center of vibration of the reflected slit image from the semiconductor wafer W in a direction orthogonal to the slit longitudinal direction. The oscillating mirror 20 is connected to an oscillator (OS
C) Mirror drive unit 24 driven by a drive signal from 23
Vibrated by

As described above, when the slit image vibrates on the light receiving slit plate 22, the light beam transmitted through the slit of the slit plate 22 is received by the sensor 25. The sensor 25 includes a plurality of light receiving elements (photoelectric conversion elements) provided corresponding to a plurality of slits on the slit plate 22. That is, a plurality of slits and light receiving elements are formed corresponding to a plurality of measurement points on the semiconductor wafer W. Note that a silicon photodiode or a phototransistor is used as the light receiving element.

The selector circuit 26 in FIG. 2 selects a signal (focus signal) relating to the height position from the sensor 25 composed of a plurality of light receiving elements, and inputs the signal to the synchronous detection circuit (PSD) 27. An AC signal having the same transfer as the drive signal from the oscillator 23 is input to the synchronous detection circuit 27, and synchronous rectification is performed based on the transfer of the AC signal.

The synchronous detection circuit 27 includes a selector circuit 26
And a plurality of detection circuits for individually and synchronously detecting the output signals at the measurement points selected from among the sensors 25, and the respective detection outputs are output to the main controller 70. The detection output signal is called a so-called S-curve signal, and becomes zero level when the center of the slit of the light receiving slit plate 22 coincides with the center of vibration of the reflected slit image from the semiconductor wafer W,
When the semiconductor wafer W is displaced upward from that state, the level becomes a positive level, and when the semiconductor wafer W is displaced downward, the level becomes a negative level. Therefore, the height position of the semiconductor wafer W where the detection output signal becomes zero level is detected as the focal point.

FIG. 3 shows a shot area S of a semiconductor wafer W.
FIG. 3 illustrates measurement points 1 to 9 distributed on A, and each of these measurement points is a slit image of light transmitted through the slit plate 22. It is known that in the shot area SA, the amount of change in the state of irregularities (process structure) increases each time a device manufacturing process is performed.
The region A1 and the region A2 in FIG. 5 indicate regions having different process structures. At the boundary between the regions A1 and A2 having different process structures, a step D
Has occurred.

The main control unit 70 is connected to the measurement points 1 to
9 that divides 9 into two groups
And a control unit 70b for controlling the arithmetic unit 70a and the multi-point focal position detecting device 10.

Next, a focus position detecting method and a projection exposure method according to the present embodiment will be described.

[Positioning Step] First, the main controller 70 controls the wafer stage WS via the wafer driving device 72.
T is driven to position the shot area SA in which the displacement in the optical axis direction is to be detected at a predetermined position that falls within the projection area (exposure area IA) of the projection optical system PL. After the positioning is completed, the height position in the optical axis direction at each of the measurement points 1 to 9 is measured by the multipoint focal position detection device 10 controlled by the control unit 70b of the main control device 70. Here, FIGS. 4 and 5
As shown in (1), the positions of the measurement points 1 to 9 are arranged apart from each other on the diagonal line of the rectangular shot area SA. Note that the measurement points may be set in another arrangement, but it is not preferable to arrange the measurement points in a lattice shape parallel to the rectangular shot area SA because it may involve a scribe line.

[Grouping Step] Next, the main control unit 7
0, the multi-point focal position detecting device 10
Are divided into groups of measurement points 1 to 9. This grouping divides at least three measurement points on the semiconductor wafer W into at least two groups. In the present embodiment, as shown in FIGS.
The upper step D is one, and the nine measurement points are divided into two groups accordingly.

As for the combination of groups in the grouping step, assuming that two groups are G1 and G2, Table 1
As shown in the figure, when there are measurement points 1 to 9, there are 9 groups of one measurement point and another measurement point, and 36 groups of two measurement points and other measurement points. There are 84 ways to group one measurement point and another measurement point, and 126 ways to group four measurement points and another measurement point.
It is possible.

[0038]

[Table 1]

[First Detection Step] Then, the controller 70b
The height position in the optical axis direction is detected for each measurement point of one of the two groups by the multi-point focal position detection device 10 controlled by. [Adjustment process] Further, the main controller 70 drives the wafer stage WST via the wafer drive device 72, and in one group, the surface position of the semiconductor wafer W is determined based on the inspection result in the first detection process. Adjustment, ie AF /
Performs AL (autofocus / autoleveling).
Thus, the influence of the tilt component is removed separately from the step in the shot area.

[Second Detection Step] After the adjustment step, the height position in the optical axis direction at each of the measurement points of the two groups is detected by the multi-point focal position detection device 10, and the output value is determined by the main control device 70. To enter. Then, the control unit 70b of the main control device 70 determines whether or not the detection values at the measurement points of each group are substantially at the same position in the group. The combination of the groups in the grouping process is changed by the calculation unit 70a of the main control device 70, and the first detection process and the adjustment process are repeatedly performed.

In this embodiment, the control unit 70b controls the arithmetic unit 70a and the multipoint focal position detecting device 10 until the measurement points in the group are at substantially the same height position, as shown in Table 1. The combination is sequentially changed from the grouping of one measurement point and another measurement point, but may be repeated in another combination order. For example, a specific combination may be performed in consideration of the past detection tendency, step information, and the like.

Further, based on the detection results obtained by grouping one measurement point and another measurement point, the grouping of two or three measurement points and other measurement points is narrowed down to some groups. You may. In these cases, it is possible to reduce the time required to find an appropriate group as compared to a case where groups are simply combined in numerical order of measurement points. In addition,
At least three measurement points are required, and the greater the number, the higher the detection accuracy, but the longer the processing time. Therefore, an appropriate number is determined in consideration of these.

As described above, when the height positions of the measurement points are all substantially the same in the group, the influence of the tilt component is removed, and the semiconductor wafer W is orthogonal to the optical axis direction.
Meaning that the surface is leveled, conversely, if at least one of the height positions of the measurement points is clearly different in the group, the surface of the semiconductor wafer W is inclined and the leveling is normal. Means not done.

For example, the step D on the surface of the semiconductor wafer W is
In the case where the semiconductor wafer W is formed as shown in FIG. 4 and the grouping is not appropriate, as shown in FIG. 6A, the semiconductor wafer W is inclined after the adjustment step. On the other hand, when AF / AL is performed based on the position information in the optical axis direction of the measurement points 7, 9 and the grouping of the two measurement points 7, 9 and the other seven measurement points, FIG.
As shown in (b) of FIG.
Are almost the same height position. At this time, measurement points 7, 9
It can be identified that the step D is located between the two points and the other measurement points.

As another example, when the step D on the surface of the semiconductor wafer W is formed as shown in FIG.
When the grouping is not appropriate, as shown in FIG. 7A, the semiconductor wafer W is inclined after the adjustment. On the other hand, it was driven down to the grouping of one measurement point 9 and the other eight measurement points, and AF / AL was performed based on the position information in the optical axis direction of other measurement points other than the measurement point 9. At this time, as shown in FIG. 7B, the adjustment is properly performed, and the height positions of the measurement points other than the measurement point 9 are substantially the same. At this time, it can be identified that the step D is located between one of the measurement points 9 and another measurement point.

Therefore, by repeating the grouping until a state in which the height positions of the measurement points are substantially the same in each group, as shown in FIGS. 4 and 5, a step D is formed between the groups. Can be identified. In addition to detecting the step by determining whether or not the height positions of the measurement points are substantially the same in each group, the difference between the average values of the height positions between the groups is the maximum value. , Or when the height d of the step D is known in advance, the same detection can be performed even if it is determined that the difference between the average values is substantially the same as the step height d.

After the appropriate AF / AL is performed as described above and the height position and the step position (step information) in the optical axis direction at each of the measurement points 1 to 9 are detected, the information and the step height are obtained. Based on this, the exposure is performed by setting the offset of the focal position at each of the measurement points 1 to 9 and positioning the semiconductor wafer W with respect to the focal position. By performing these steps for one or more shots in the semiconductor wafer W, if the wafer or this wafer is the first wafer in the lot, it is possible to know the tendency of the step shape in the shot area in the lot, Measurement accuracy and exposure accuracy can be improved.

In the case of a semiconductor wafer having no step, there is no difference in the result even if the combination of grouping is changed as described above. In this case, exposure may be performed without giving an offset.

If the tilt component in the shot area has been removed in advance, the above-described adjustment step is not always necessary. It is conceivable that the removal of the tilt component is further provided with, for example, a collimator type leveling detection system, and the tilt is controlled thereby.

The present invention also includes the following embodiments. (1) In the above embodiment, for the semiconductor wafer W having one step D, the measurement point is divided into two groups and the focus position and the step information are detected, but the semiconductor wafer W having two or more steps is detected. The detection can be performed similarly. In this case, the group may be divided into three or more groups and the detection may be performed in the same manner as described above. Alternatively, after detecting the position of a specific step among the two or more steps, other groups may be detected based on the detection result. The detection may be performed stepwise so as to detect the step position.

(2) The application of the exposure apparatus is not limited to an exposure apparatus for manufacturing semiconductors. For example, an exposure apparatus for a liquid crystal for exposing a liquid crystal display element pattern to a square glass plate, a thin film magnetic head Can also be widely applied to an exposure apparatus for manufacturing a semiconductor device.

(3) The light source of the exposure apparatus of this embodiment is g
Line (436 nm), i-line (365 nm), KrF excimer laser (248 nm), ArF excimer laser (19
3 nm) and F2 laser (157 nm), as well as charged particle beams such as X-rays and electron beams. For example, when using an electron beam, thermionic emission type lanthanum hexaborite (LaB6), tantalum (T
a) can be used. (4) The magnification of the projection optical system is not limited to a reduction system, but may be any of an equal magnification and an enlargement system.

(5) When far ultraviolet rays such as an excimer laser are used as the projection optical system, a material that transmits the far ultraviolet rays such as quartz or fluorite is used as the glass material.
When a line is used, a catadioptric or refraction type optical system is used (use a reticle of a reflection type). When an electron beam is used, an electron optical system including an electron lens and a deflector is used as the optical system. You can use it. It goes without saying that the optical path through which the electron beam passes is in a vacuum state.

(6) When a linear motor (see US Pat. No. 5,623,853 or US Pat. No. 5,528,118) is used for a wafer stage or a reticle stage, an air levitation type using an air bearing and a magnetic levitation type using Lorentz force or reactance force are used. Either may be used. Also, the stage
A type that moves along a guide or a guideless type that does not have a guide may be used.

(7) The reaction force generated by the movement of the wafer stage is (as described in US Pat. No. 5,528,118)
You may mechanically escape to the floor (ground) using a frame member. (8) The reaction force generated by the movement of the reticle stage is
A frame member may be used to mechanically escape to the floor (as described in US S / N 416558).

(9) An illumination optical system and a projection optical system composed of a plurality of lenses are incorporated in the exposure apparatus main body to perform optical adjustment, and a reticle stage or a wafer stage composed of many mechanical parts is mounted on the exposure apparatus main body. Connect wiring and piping, and make comprehensive adjustments (electrical adjustment, operation check, etc.)
By doing so, the exposure apparatus of the present embodiment can be manufactured. It is desirable that the manufacture of the exposure apparatus be performed in a clean room in which the temperature, cleanliness, and the like are controlled.

(10) For a semiconductor device, a step of designing the function and performance of the device, a step of manufacturing a reticle based on the design step, a step of manufacturing a wafer from a silicon material, and a reticle by the exposure apparatus of the above-described embodiment. The device is manufactured through a step of exposing the pattern to a wafer, a device assembling step (including a dicing step, a bonding step, and a package step), an inspection step, and the like.

[0058]

According to the present invention, the following effects can be obtained. (1) According to the surface position detecting method according to the first aspect and the surface position detecting device according to the sixth aspect, the position detection is repeated by changing the combination of the groups in the grouping of the measurement points, and the position detection is obtained. Since information on steps on the substrate is obtained based on the position information for each group, when there is no step between the measurement points in the group, the tendency of the position information is significantly different compared to when there is a step. As a result, information such as the step position can be obtained, and accurate autofocus and auto-leveling can be performed by accurately recognizing the step position and distinguishing between the step and the tilt component.

(2) According to the surface position detecting method of the second aspect, the detecting step includes a first detecting step of detecting a position in the optical axis direction of each measurement point of one of the groups; An adjustment step of adjusting the surface position of the substrate based on the inspection result in the first detection step; and a second detection step of detecting the position of the measurement point of each group in the optical axis direction after the adjustment step, Since the information regarding the step is detected based on the combination of the groups when the measurement points of each group obtained in the second detection step are substantially at the same position in the group, information such as the step position after appropriate leveling is obtained. Can be accurately detected.

(3) According to the surface position detection method of the third aspect, the positions in the optical axis direction at at least three measurement points are detected by the focal position detection sensor for detecting the focal position of the projection optical system. The surface position at the point can be detected as information on the focal position.

(4) According to the projection exposure method according to the fourth aspect, the projection exposure apparatus according to the seventh aspect, and the semiconductor device manufacturing method according to the eighth aspect, the level difference obtained by the above-described surface position detection method or apparatus. Based on the information, the substrate is positioned with respect to the focal position of the projection optical system and exposure is performed.
High-precision exposure can be performed without defocusing even on a substrate surface having a step, and the yield in the exposure step can be improved.

(5) According to the projection exposure method of the fifth aspect, the focal position of the projection optical system at each measurement point is offset based on the detected step information, so that the optimum process offset is automatically obtained. This eliminates the need for performing test exposure in advance and observing with a SEM or the like, thereby reducing labor and time.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram illustrating an embodiment of a projection exposure apparatus including a surface position detection device according to the present invention.

FIG. 2 is a main part configuration diagram showing one embodiment of a projection exposure apparatus provided with a surface position detecting device according to the present invention.

FIG. 3 is a plan view showing measurement points in a shot area in an embodiment of the projection exposure apparatus including the surface position detecting device according to the present invention.

FIG. 4 is a plan view showing a step position and a measurement point in a shot area in an embodiment of the projection exposure apparatus including the surface position detecting device according to the present invention.

FIG. 5 is a plan view showing a step position and a measurement point in a shot area in an embodiment of the projection exposure apparatus including the surface position detecting device according to the present invention.

FIG. 6 is a view showing an embodiment of a projection exposure apparatus including a surface position detecting apparatus according to the present invention, in which an improper grouping is performed in the shot area in FIG. FIG.

FIG. 7 is a view showing an embodiment of a projection exposure apparatus including a surface position detecting device according to the present invention, in which an improper grouping is performed in the shot area in FIG. FIG.

FIG. 8 is an explanatory diagram showing a position state when leveling adjustment is performed in a conventional example of a projection exposure apparatus including a surface position detection device according to the present invention.

[Explanation of symbols]

1 to 9 measurement points 10 multi-point focal position detection device (focal position detection sensor, detection unit) 40 projection exposure device 70 main control device 70a calculation unit 70b control unit 72 wafer driving device AF1 irradiation optical system AF2 light receiving optical system AX optical axis D Step PL Projection optical system R Reticle W Semiconductor wafer

Claims (8)

[Claims] 1. A surface position detecting method for detecting a position in a direction of an optical axis of a projection optical system on a substrate surface onto which a mask pattern is transferred via a projection optical system, wherein at least three measurement points on the substrate are at least two measurement points. A grouping step of dividing into two groups, and a detection step of detecting the position information in the optical axis direction in each group based on a measurement result of each measurement point, wherein a combination of the groups in the grouping step is changed. A surface position detection method, wherein the detection step is repeated, and information on a step on the substrate is obtained based on the position information for each group obtained in the detection step. 2. The detecting step includes: a first detecting step of detecting a position in the optical axis direction of each measurement point of one of the groups, based on an inspection result in the first detecting step. An adjusting step of adjusting the surface position of the substrate, and a second detecting step of detecting a position of the measurement point of each group in the optical axis direction after the adjusting step. 2. The surface position detecting method according to claim 1, wherein the information about the step is detected based on a combination of the groups when the measured points of the groups are substantially at the same position in the group. 3. The surface position according to claim 1, wherein a position in the optical axis direction at the at least three measurement points is detected by a focal position detection sensor that detects a focal position of the projection optical system. Detection method. 4. A projection exposure method for projecting and exposing a pattern on a mask onto a substrate surface via a projection optical system, wherein the step is obtained by the surface position detection method according to claim 1. A projection exposure method, wherein the exposure is performed by positioning the substrate with respect to a focal position of the projection optical system based on information. 5. The projection exposure method according to claim 4, wherein a focal position of the projection optical system at each of the measurement points is offset based on the detected step information. 6. A surface position detecting device for detecting a position in a direction of an optical axis of a projection optical system on a substrate surface to which a mask pattern is transferred via a projection optical system, wherein at least three measurement points on the substrate are at least two points. A calculation unit that divides the calculation unit into two groups, a detection unit that detects the position information in the optical axis direction in each group based on the measurement result of each measurement point, and a control unit that controls the calculation unit and the detection unit. The control unit repeats the detection of the position information by the detection unit by changing the combination of groups by the calculation unit,
A surface position detection device, wherein information on a step on the substrate is obtained based on position information for each group obtained by the detection unit. 7. A projection exposure apparatus for projecting and exposing a pattern on a mask onto a substrate surface via a projection optical system, and detecting a surface position of the substrate with respect to a focal position of the projection optical system. A projection exposure apparatus, comprising: a surface position detecting device. 8. A method for manufacturing a semiconductor device having a step of transferring a pattern of a mask onto a substrate, wherein the pattern is transferred using the projection exposure apparatus according to claim 7.