JP2001326161A - Exposure method and exposure apparatus, device manufacturing method and microdevice - Google Patents

Abstract

(57) Abstract: In an exposure method, an exposure apparatus, a device manufacturing method, and a microdevice, even when the optical characteristics of a position detecting optical system are changed, a correct focus position is made corresponding to the optical characteristics. Perform alignment measurement. SOLUTION: The optical characteristics of a position detection optical system 1 are arbitrarily changed, and an actually measured focal position is corrected in accordance with the changed optical characteristics, that is, corrected with a focus offset value corresponding to the optical characteristic setting, and further corrected. Since the surface of the substrate W is aligned with the focal position, errors due to focus shift are reduced, and accurate alignment measurement can be performed with correct focus.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a micro device such as a semiconductor device, a liquid crystal display device, an image pickup device (CCD), and a thin film magnetic head by exposing a pattern formed on a reticle as a mask to light. Exposure method and exposure apparatus used in a photolithography process for exposing a substrate on which a chemical agent has been applied, and device manufacturing methods and microdevices, particularly required for relative alignment between a reticle pattern and a substrate This relates to correction of a baseline amount, which is one operation amount.

[0002]

2. Description of the Related Art In a photolithography process for manufacturing a semiconductor device or a liquid crystal display device, a photosensitive agent is applied on a substrate surface (a semiconductor wafer surface or a liquid crystal glass substrate surface),
An exposure apparatus is used which obtains a semiconductor element or a liquid crystal display element by exposing an image of a reticle having a desired element circuit pattern formed on the substrate surface through a projection optical system. As shown in FIG. 4, the exposure apparatus includes a light source (not shown) that emits illumination light for exposure applied to a pattern formed on a reticle R, and a projection for reducing and projecting the pattern on a surface of a substrate W. An optical system PL and a wafer stage WST for moving the substrate W under the projection optical system PL are schematically configured.

Incidentally, in the photolithography process, in the above-described exposure operation, some measures are required so that a plurality of shot areas on the substrate W are aligned with the respective reticle patterns. In order to respond to this request, an alignment mark (mark) A is usually provided on the substrate W in association with each shot area, and is prepared separately from the projection optical system PL and detected by the position detection optical system Q. As a result, alignment between the reticle pattern and the shot area on the substrate W, that is, alignment is performed.

The position detecting optical system Q is an optical system of an off-axis alignment microscope having an optical axis QX parallel to the optical axis PX of the above-mentioned projection optical system PL. Illuminating optical unit Q1 for irradiating the light, and light generated by illuminating the alignment mark A is incident thereon, and an image pickup device (a so-called image sensor, such as a CCD camera or CCD)
A sensor or a MOS type sensor) comprises an imaging optical section Q2 for forming an image of the alignment mark A on the Qc, and an image processing section Q3 connected to the imaging element Qc. Here, in the imaging optical section Q2, an index plate Qk provided with an index mark is provided in the middle of the optical path,
The image of the index mark on the index plate Qk is formed on the image sensor Qc. The image processing unit Q3 detects the amount of displacement between the image of the index mark and the image of the alignment mark A formed on the image sensor Qc. An alignment controller (not shown) moves and aligns wafer stage WST based on the amount of displacement and the position of wafer stage WST detected by the laser interferometer when imaging alignment mark A.

In the above-described alignment, an operation amount generally called a baseline amount is required, and is obtained as follows. Now, wafer stage WST
The reference mark FM provided on the top is used for the position detection optical system Q.
To detect. At this time, the amount of positional deviation from the image of the index mark on the index plate Qk is detected, and the reference mark F
The position of wafer stage WST when M is detected is determined. Further, based on the position shift amount and the position of wafer stage WST, position X1 of wafer stage WST when the position shift amount becomes zero is determined. This position X1 is stored in a storage area of an alignment controller (not shown) of the exposure apparatus.

Next, the stage WST is moved so that the reference mark FM is almost immediately below the projection optical system PL, that is, at a position conjugate with the reticle mark Rm with respect to the projection optical system PL. An image of the reticle mark Rm and an image of the reference mark FM projected by the projection optical system PL are formed on an image sensor of an alignment optical system (not shown) arranged above the reticle R. Incidentally, the reticle mark Rm is a reference when performing alignment. The alignment optical system detects the amount of displacement between the two mark images. The alignment controller obtains a position X2 of the stage WST when the amount of the displacement becomes zero based on the amount of the displacement and the position of the stage WST detected by the laser interferometer. This determined position X2
Are stored in the storage area of the alignment controller. The base line amount B is obtained as the base line amount B = X2-X1, based on the positions X1 and X2 with respect to the stage obtained as described above.

When an image of a reticle pattern is to be transferred to one shot area on the substrate W, the position detection optical system Q detects an alignment mark A attached to the shot area to determine its position. Wafer stage WST on the basis of the
To move. As a result, the image of the reticle pattern Rm and its shot area are accurately aligned. As described above, since the baseline amount B is an extremely important operation amount in the photolithography process, a strictly accurate measurement value is required. However, there are various difficult problems to be solved here.

For example, in the case of manufacturing a semiconductor device, a plurality of types of semiconductor wafers having different reflectivities are used, and the optical characteristics and thin films (WSi, SiN) of a plurality of layers laminated on the semiconductor wafer are used. , SiO
₂ etc.) are different. For this reason, in the case of illumination light having a wide wavelength band, reflected light on the wafer surface tends to cause multiple interference, and it may be difficult to obtain a sharp signal. Therefore, it is difficult to always accurately detect the position of the alignment mark using the same position detection optical system regardless of the type of the semiconductor wafer or the layer.

In order to solve this problem, a technique has been proposed in which the position detection optical system Q is improved to improve the detection accuracy of the alignment mark image. That is, the illumination optical unit Q1 and the imaging optical unit Q2 of the position detection optical system Q
In addition, an illumination wavelength switching mechanism and a phase difference plate switching mechanism capable of arbitrarily inserting / removing a wavelength selection filter q1 and a phase difference plate q2 of an illumination wavelength with respect to an optical path, respectively, are provided. This is a technique for satisfactorily detecting an image on the image sensor Qc by changing it.

In this technique, the illumination wavelength switching mechanism sets the wavelength selection filter q1 according to the material of the wafer surface, and irradiates the illumination light in a wavelength band in a region where multiple interference is unlikely to occur, thereby providing high intensity. A signal can be obtained. Further, by setting the phase difference plate q2 in accordance with the reflected light from the wafer surface by the phase difference plate switching mechanism, a phase difference is partially generated in the 0th-order light or the 1st-order light of the reflected light, and high intensity is obtained. Can be obtained.

In the position detection optical system Q as described above, the detection of the alignment mark can be achieved satisfactorily. Note that focusing is very important for such accurate position measurement, and there is a case where an autofocus sensor (not shown) is provided exclusively for the position detection optical system Q.

[0012]

SUMMARY OF THE INVENTION The above prior arts include:
The following issues remain. In the case of the above prior art, by switching the wavelength selection filter and the phase difference plate and arranging them on the optical axis, the optical characteristics of the position detection optical system are changed, and as a result, the alignment accuracy is affected. Here, the change of the optical characteristics may be caused by a shift of the focus position in the position detection optical system (the optical system of the alignment microscope). That is, the switching of the wavelength selection filter or the phase difference plate inserted into the optical system causes a shift of the focus position, causing an error in the alignment, and making it difficult to perform accurate alignment.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. Even when the optical characteristics of a position detecting optical system are changed, alignment measurement can be performed at a correct focus position corresponding to the optical characteristics. An object of the present invention is to provide an exposure method and an exposure apparatus, and a device manufacturing method and a micro device.

[0014]

The present invention has the following features to attain the object mentioned above. In other words, referring to FIG. 1, the exposure method of the present invention detects the mark (A) on the substrate (W) by the position detecting optical system (1), and based on the detection result, the substrate and the mask (R). An exposure method for exposing the pattern of the mask on the substrate by adjusting a positional relationship between the focus position and the focus of the position detection optical system based on reflection of illumination light applied to the substrate with constant optical characteristics. A focus detection step of actually measuring a position, and a position detection step of detecting a position of a mark on the substrate by the position detection optical system, wherein the position detection step arbitrarily changes optical characteristics of the position detection optical system Then, the focal position actually measured in the focus detecting step is corrected according to the changed optical characteristic, and the surface of the substrate is aligned with the corrected focal position.

Further, the exposure apparatus of the present invention detects the mark (A) on the substrate (W) by the position detecting optical system (1),
An exposure apparatus for adjusting a positional relationship between a substrate and a mask (R) based on a result of the detection, and exposing the pattern of the mask to the substrate, wherein the position detection optical system is configured to apply a predetermined optical property to the substrate. A focus detection mechanism (2) for actually measuring a focus position based on the reflection of the illuminated illumination light; and a position detection mechanism (3) for detecting a position of a mark on the substrate. An optical property changing mechanism (8, 12) for arbitrarily changing the optical property of the position detecting optical system; and correcting the focus position actually measured in the focus detecting step according to the changed optical property. A focus adjusting mechanism (4) for positioning the surface of the substrate.

In these exposure methods and exposure apparatuses, the optical characteristics of the position detecting optical system (1) are arbitrarily changed, and the actually measured focal position is corrected according to the changed optical characteristics, that is, the focus corresponding to the optical characteristic setting. Since the correction is performed with the offset value and the surface of the substrate (W) is aligned with the corrected focus position, an error due to a focus shift is reduced, and accurate alignment measurement can be performed with correct focus.

The device manufacturing method of the present invention is a device manufacturing method manufactured through a transfer step of transferring a pattern of a mask (R) onto a substrate (W). Performing a process. In addition, the micro device of the present invention is a mask (R)
A micro device manufactured through a transfer step of transferring the pattern to a substrate (W), wherein the transfer step is performed by the exposure apparatus of the present invention.

In these device manufacturing methods and microdevices, since the transfer step is performed by the above-described exposure method or the above-described exposure apparatus, exposure can be performed by accurate alignment measurement even when optical characteristics are switched, and a highly accurate device can be obtained. Is obtained.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an exposure method and an exposure apparatus, a device manufacturing method, and a micro device according to the present invention will be described with reference to FIGS.

FIG. 1 is a view schematically showing the overall configuration of an exposure apparatus according to the present embodiment. The exposure apparatus includes an off-axis position detecting optical system 1. The position detection optical system 1 includes a focus detection mechanism 2 that measures a focus position based on the reflection of illumination light applied to the substrate W with constant optical characteristics, and a position that detects the position of an alignment mark A on the substrate W. And a detection mechanism 3. Further, the exposure apparatus of the present embodiment controls the entire exposure apparatus and corrects the focal position actually measured by the focus detection mechanism 2 according to the optical characteristic (illumination wavelength / phase difference plate) to be changed. A main controller (focus adjustment mechanism) 4 for aligning the surface of the substrate W with the focus position thus set.

The position detecting mechanism 3 includes an illumination optical unit 5 and
It is schematically configured by an imaging optical unit 6 and an image processing unit 7. The illumination optical unit 5 includes an illumination light source 5a for illumination light, a condenser lens (not shown), an illumination field stop (not shown), and a wavelength switching mechanism (optical) for switching the wavelength of the illumination light to be irradiated on the substrate W. Characteristic changing mechanism) 8, a relay lens 9, an illuminating light beam restricting member (not shown) for restricting the passage of the light beam emitted from the illuminating light source 5a, and illuminating the alignment mark A or the like on the substrate W with an annular zone. Splitter 10
And an objective lens 11.

As the illumination light source 5a, one that emits a broadband illumination light beam (broadband light) such as a halogen lamp is used. In the illumination optical section 5, the light beam from the illumination light source 5a is irradiated onto the substrate W via the above-described members arranged along the traveling direction of the light. The wavelength switching mechanism 8 includes three types of wavelength selection filters 8a, 8b, 8
c, and these wavelength selection filters 8a, 8
b and 8c can be arbitrarily arranged on the optical axis of the illumination light beam and can be switched. Wavelength selection filters 8a, 8b, 8c
Are, for example, 530-620 nm band, 620-710 nm
Band or a band-pass filter that selectively transmits wavelengths in the 710 to 800 nm band.

Next, the image forming optical section 6 will be described. The configuration is described in the order in which the reflected light from the surface of the substrate W progresses. First, the objective lens 11 and the beam splitters 10 and 21 described above are placed. A phase switching mechanism (optical characteristic changing mechanism) 12 for switching the phase, a relay lens 13, other optical members and the like (a beam splitter, an index plate, an image forming beam limiting aperture, etc., not shown), and an image sensor 14 are arranged.

The phase switching mechanism 12 has two types of phase difference plates 12a and 12b.
a and 12b are arbitrarily arranged on the optical axis of the reflected light and can be switched. The phase difference plates 12a and 12b cooperate with the above-mentioned illumination light beam restricting member to increase the accuracy of detecting particularly low-level alignment marks. The phase difference plates 12a and 12b are provided on a surface having an optical Fourier transform relationship with respect to the substrate W (hereinafter, referred to as an imaging pupil surface). Therefore, the phase difference plates 12a, 12b
The illumination light flux limiting member and the illumination light flux limiting member are conjugate to each other (image relationship).

As an example of the phase difference plates 12a and 12b,
As shown in FIGS. 2A and 2B, a ring-shaped portion having a multilayer structure in which a metal thin film q23 and a dielectric film q24 are stacked on a plane formed by a transparent body (glass plate such as quartz) q22. q25 is formed. The annular shape portion q25 is formed at a position conjugate with the annular opening of the illumination light flux limiting member. Therefore, the phase difference plate 12
“a” has a function of shifting the phase of the 0th-order diffracted light emitted from the substrate W by the function of the annular shape portion q25. Specifically, the transmitted light is reduced by the metal thin film q23, and the phase of the transmitted light is shifted by the dielectric film q24. This allows
The light from the substrate W causes a phase difference between the light passing through the orbicular shape portion q25 and the light passing through the other region in the phase difference plate 12a. Such a configuration is similar to a phase difference filter in a conventionally well-known phase contrast microscope. By providing this in the image forming optical system 5, the image forming characteristics of the alignment mark A can be changed and detected. Accuracy can be improved. The layer thickness of the dielectric film q24 is appropriately determined by its refractive index n and the wavelength λ of the light source.

The image pickup device 14 is provided for receiving reflected light from the substrate W passing through the above-mentioned image forming optical unit 6, recognizing (image forming) these as images, and converting them into electric signals. . Usually, a CCD camera, an area image sensor, or the like is used.

Next, the image processing section 7 will be described. The image processing unit 7 processes an electric signal generated by the image pickup device 14 and generates a control signal for moving the wafer stage WST to realize alignment. The image processing unit 7 includes an amplifier 15, an A / D converter 16, an alignment controller 17, and a baseline memory 18.
It is composed of Among these, the alignment controller 17 and the baseline memory 18 function as a baseline correction device that substantially corrects the baseline.

The amplifier 15 is provided to amplify an electric signal based on the image recognized by the image pickup device 14, that is, an alignment mark detection signal at a desired amplification factor. The amplification factor at this time is basically arbitrary, and the state of the electric signal of the captured image (amplitude, S / N ratio, etc.)
Thus, it is possible to appropriately change the amplification factor.

The A / D converter 16 is provided for converting the amplified electric signal from an analog signal to a digital signal. Alignment controller 17
Is provided for performing arithmetic processing on the digital signal sent from the A / D converter 16. The alignment controller 17 performs alignment based on the detected position. The baseline memory 18 is a memory for storing a baseline correction value generated by a change in the optical characteristics of the position detection optical system 1 or a change in the electric circuit characteristics. The baseline memory 18 is also an area for storing a baseline amount measured by the position detection optical system 1 that has not been changed by the optical characteristic changing device or the electric circuit characteristic changing device.

In this embodiment, a projection optical system PL, a wafer stage WST, and the like are provided. These are the same as those described in the section of the prior art. As shown in FIG. 1, a reticle R supported by a reticle stage (not shown) is arranged on the object plane side of the projection optical system PL, and its pattern surface is exposed to illumination light for exposure (exposure beam) by an illumination optical system (not shown). ). The projection optical system PL has a plurality of refractive optical elements arranged along the optical axis, and projects an image of the pattern of the reticle R on the substrate W in a reduced size.

Above reticle R, reference plate P arranged on wafer stage WST by irradiation of exposure illumination light
Light generated from a reference mark (called a fiducial mark) on T and passing through the projection optical system PL and light generated from the reticle mark are received by an image sensor (CCD) via an objective optical system, An alignment optical system (not shown) for detecting the amount of displacement between the images of the two marks is arranged. This alignment optical system is used at the time of baseline measurement, and the measurement operation is the same as that described with reference to FIG.

On the image plane side of the projection optical system PL, there is arranged a wafer stage WST which holds the substrate W and is two-dimensionally movable in a plane orthogonal to the optical axis of the projection optical system PL. It is always measured by a laser interferometer (not shown). Note that, in the field of view of the projection optical system PL, that is, in the irradiation area of the illumination light for exposure, the substrate W has its exposed surface (eg, surface).
The wafer is held by the wafer stage WST so as to be arranged on a second surface (image surface) orthogonal to the optical axis.

On wafer stage WST, reference plate P on which reference marks used for baseline measurement or the like are formed.
T is provided. The reference mark includes two sets of line and space patterns each having periodicity in the X and Y directions. The output signal of the laser interferometer is input to alignment controller 17 and main controller 4 respectively.

The alignment controller 17 detects the position (coordinate value) of the alignment mark A or the reference mark on the substrate W as described above, and the main controller 4 determines the position based on the detected position and the output of the laser interferometer. Then, the drive of the wafer stage WST is controlled via the stage drive system SM, and the alignment of the shot area on the substrate W with the pattern image of the reticle R is executed.

The focus detecting mechanism 2 includes an autofocus light source 19 for emitting broadband illumination light such as a halogen lamp, beam splitters 20 and 21, a relay lens 22, an autofocus sensor 23, slits S1 and S2, It has. In the focus detection mechanism 2, light from the auto-focus light source 19 is
1. The substrate W is irradiated via the beam splitter 20, the relay lens 22, the beam splitters 21 and 10, and the objective lens 11, and the reflected light thereof is reflected by the objective lens 11, the beam splitters 10, 21, the relay lens 22, and the beam splitter 20. Is incident on the auto focus sensor 23 through the slit S2. The slit S <b> 1 is for irradiating the light from the autofocus light source 19 to a location slightly distant from the position detection area of the position detection mechanism 3. The slit S2 is provided with an illumination light source 5a for position detection.
This is for shielding the reflected light of the illumination light from the substrate from the substrate, passing the reflected light of the light from the autofocus light source 19 for focus detection from the substrate, and guiding it to the sensor 23.
Main controller 4 also receives a signal from autofocus sensor 23 and controls stage drive system SM to adjust the vertical position of wafer stage WST.

In the exposure apparatus of the present embodiment, in order to perform focusing in the imaging optical unit 6 of the position detecting optical system 1, first, before actually performing focusing and alignment on the substrate W, a shipping stage, etc. To measure the focus offset. That is, under the condition of observing the reference mark on the reference wafer or the reference plate PT on the wafer stage WST, the illumination wavelength to be switched (the wavelength selection filters 8a, 8b, 8c) and the phase difference plates 12a, 12a,
The best focus point is measured in advance for each 2b, and the wavelength selection filters 8a, 8b, 8c and the retarder 12a,
The focus difference (focus offset value) between the case where 12b is not used and the case of each switching state is stored in a memory in main controller 4.

Thereafter, when focusing is actually performed on the substrate W, the focus measurement is performed with light having a wavelength as wide as possible without switching the wavelength and the phase difference by the broadband illumination light beam from the light source 19 for autofocus. Do. At this time, the main controller 4 adds a pre-stored focus offset value corresponding to the setting of the illumination wavelength and the phase difference switching used to the measurement value actually measured by the autofocus sensor 23, The result is used as a vertical movement control target value of wafer stage WST to control stage drive system SM. Thus, the position detection optical system 1
After the focal position is accurately adjusted according to the optical characteristics of the above, alignment is performed.

That is, in the present embodiment, the illumination wavelength (the wavelength selection filters 8a, 8a) used for the actual alignment is used.
b, 8c) and the focus offset values corresponding to the phase difference plates 12a, 12b to perform focus adjustment so that even if the illumination wavelength or the phase difference plate is arbitrarily switched, the alignment mark A can be accurately detected. The position measurement can be performed, and the substrate W can be positioned.

The present invention includes the following embodiments. (1) The exposure apparatus of the present embodiment can be applied to a scanning type exposure apparatus that exposes a mask pattern by synchronously moving a mask and a substrate. (2) The exposure apparatus of the present embodiment can be applied to a step-and-repeat type exposure apparatus that exposes a mask pattern while keeping the mask and the substrate stationary and sequentially moves the substrate in steps. it can.

(3) The exposure apparatus of this embodiment can be applied to a proximity exposure apparatus that exposes a mask pattern by bringing a mask and a substrate into close contact without using a projection optical system. (4) The application of the exposure apparatus is not limited to an exposure apparatus for manufacturing a semiconductor, and for example, manufactures an exposure apparatus for a liquid crystal that exposes a liquid crystal display element pattern to a square glass plate, and a thin film magnetic head. Widely applicable to an exposure apparatus.

(5) 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 (1
93nm), F2 laser (157nm), X
A charged particle beam such as a beam or an electron beam can be used. For example, when an electron beam is used, thermionic emission type lanthanum hexaborite (LaB6), tantalum (T
a) can be used. Further, when an electron beam is used, a structure using a mask may be used, or a pattern may be formed directly on a substrate without using a mask.

(6) The magnification of the projection optical system may be not only a reduction system but also any one of an equal magnification system and an enlargement system. (7) As a projection optical system, when far ultraviolet rays such as an excimer laser are used, a material that transmits the far ultraviolet rays such as quartz or fluorite is used as a glass material. If the reticle is of a reflection type, an electron optical system including an electron lens and a deflector may be used as the optical system. It goes without saying that the optical path through which the electron beam passes is in a vacuum state.

(8) When a linear motor is used for the wafer stage or the reticle stage, either an air levitation type using an air bearing or a magnetic levitation type using Lorentz force or reactance force may be used. Also,
The stage may be a type that moves along a guide or a guideless type that does not have a guide.

(9) A planar motor is used as a stage driving device.
When using a magnet, one of the magnet unit and the armature unit may be connected to the stage, and the other of the magnet unit and the armature unit may be provided on the moving surface side (base) of the stage. (10) The reaction force generated by the movement of the wafer stage may be mechanically released to the floor (ground) using a frame member, as described in JP-A-8-166475. The present invention is also applicable to an exposure apparatus having such a structure.

(11) The reaction force generated by the movement of the reticle stage may be mechanically released to the floor (ground) by using a frame member, as described in JP-A-8-330224. The present invention is also applicable to an exposure apparatus having such a structure.

(12) As described above, the exposure apparatus according to the embodiment of the present invention converts various subsystems including the components described in the claims of the present application into predetermined mechanical accuracy, electrical accuracy, and optical accuracy. Manufactured by assembling to maintain accuracy. Before and after this assembly, adjustments to achieve optical accuracy for various optical systems, adjustments to achieve mechanical accuracy for various mechanical systems, and various electric systems to ensure these various accuracy Are adjusted to achieve electrical accuracy. The process of assembling the exposure apparatus from various subsystems includes mechanical connections, wiring connections of electric circuits, and piping connections of pneumatic circuits among the various subsystems. It goes without saying that there is an assembling process for each subsystem before the assembling process from these various subsystems to the exposure apparatus. When the process of assembling the various subsystems into the exposure apparatus is completed, comprehensive adjustment is performed, and various precisions of the entire exposure apparatus are secured.
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.

(13) As shown in FIG. 3, in the semiconductor device, step 20 for designing the function and performance of the device is performed.
1. Step 202 of manufacturing a mask (reticle) based on this design step; Step 203 of manufacturing a wafer from a silicon material; Wafer processing step 204 of exposing a reticle pattern to the wafer by the exposure apparatus of the above-described embodiment; Assembly step (including dicing process, bonding process, package process) 2
05, manufactured through the inspection step 206 and the like.

[0048]

According to the present invention, the following effects can be obtained.
In the exposure method and the exposure apparatus of the present invention, the optical characteristics of the position detection optical system are arbitrarily changed, the measured focal position is corrected according to the changed optical characteristics, and the substrate surface is aligned with the corrected focal position. Therefore, errors due to focus shift are reduced, accurate alignment measurement can be performed with correct focus, and more accurate exposure can be realized.

Further, in the exposure method of the present invention, in the position detecting step, the focal position measured by the position detecting optical system of the optical characteristic to be changed in advance and the focal position measured by the position detecting optical system of the optical characteristic to be changed are set in advance. Is measured, and the correction is performed based on the difference, so that it is not necessary to measure the difference in the focal position every time the optical characteristics are switched, and the throughput of the switching operation can be improved.

Further, in the exposure method and the exposure apparatus according to the present invention, as the optical characteristics, the wavelength of the illumination light applied to the substrate is changed and switched, so that the illumination used for the alignment in accordance with the material of the substrate surface. The focus offset value can be set according to the wavelength.

Further, in the exposure method and the exposure apparatus according to the present invention, by changing / switching the phase of the illuminating light irradiated and reflected on the substrate as the optical characteristic, the position according to the reflected light from the substrate is changed. When using a retardation plate,
The focus offset value can be set.

According to the device manufacturing method and the micro device of the present invention, since the transfer step is performed by the above-described exposure method or the above-described exposure apparatus, exposure can be performed by accurate alignment measurement even when optical characteristics are switched, and high accuracy can be obtained. An accurate device can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic overall configuration diagram showing an exposure apparatus in an embodiment of an exposure method and an exposure apparatus, a device manufacturing method, and a microdevice according to the present invention.

FIG. 2 is a front view and a cross-sectional view showing a retardation plate used in an embodiment of an exposure method and an exposure apparatus, a device manufacturing method, and a micro device according to the present invention.

FIG. 3 is a flowchart illustrating an example of a semiconductor device manufacturing process.

FIG. 4 shows a conventional example of an exposure method and an exposure apparatus, and a device manufacturing method and a micro device according to the present invention.
FIG. 1 is a schematic overall configuration diagram showing an exposure apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 position detection optical system 2 focus detection mechanism 3 position detection mechanism 4 main controller (focus adjustment mechanism) 8 wavelength switching mechanism (optical property changing mechanism) 8 a, 8 b, 8 c wavelength selection filter 12 phase switching mechanism (optical property changing mechanism) 12a, 12b Phase difference plate A Alignment mark PL Projection optical system R Reticle (mask) W Wafer (substrate)

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) H01L 21/30 526A

Claims (9)

[Claims] 1. An exposure method for detecting a mark on a substrate by a position detection optical system, adjusting a positional relationship between the substrate and a mask based on a result of the detection, and exposing the mask pattern on the substrate. A focus detection step of actually measuring a focus position of the position detection optical system based on reflection of illumination light applied to the substrate with a fixed optical characteristic; and detecting a position of a mark on the substrate with the position detection optical system. A position detection step, wherein the position detection step arbitrarily changes the optical characteristics of the position detection optical system, and corrects the focal position actually measured in the focus detection step according to the changed optical characteristics. An exposure method comprising: aligning a surface of the substrate with a focused focal position. 2. The method according to claim 1, wherein the step of detecting a difference between a focal position of the position detecting optical system measured in advance with the constant optical characteristic and a focal position of the position detecting optical system measured with the changed optical characteristic. 2. The exposure method according to claim 1, wherein measurement is performed, and the correction is performed based on the difference between the focal positions. 3. The exposure method according to claim 1, wherein the optical characteristic to be changed is at least a wavelength of illumination light irradiated on the substrate. 4. The exposure method according to claim 1, wherein the optical characteristic to be changed is at least a phase of illumination light irradiated on the substrate and reflected. 5. A method of manufacturing a device, which is manufactured through a transfer step of transferring a pattern of a mask onto a substrate, wherein the transfer step is performed by the exposure method according to claim 1. Manufacturing method of the device. 6. An exposure apparatus for detecting a mark on a substrate by a position detection optical system, adjusting a positional relationship between the substrate and the mask based on a result of the detection, and exposing the pattern of the mask on the substrate. The position detection optical system, a focus detection mechanism that actually measures the focus position based on the reflection of the illumination light that irradiates the substrate with certain optical characteristics, and a position detection mechanism that detects the position of the mark on the substrate The position detecting mechanism comprises: an optical property changing mechanism for arbitrarily changing the optical property of the position detecting optical system; and correcting the focus position actually measured by the focus detecting mechanism in accordance with the changing optical property. An exposure apparatus, comprising: a focus adjustment mechanism that aligns the surface of the substrate with a focused focus position. 7. The exposure apparatus according to claim 6, wherein the optical characteristic changing mechanism has a wavelength switching mechanism for switching a wavelength of illumination light irradiated on the substrate as the optical characteristic. 8. The exposure apparatus according to claim 6, wherein the optical characteristic changing mechanism has a phase switching mechanism that switches a phase of illumination light irradiated on the substrate and reflected as the optical characteristic. . 9. A microdevice manufactured through a transfer step of transferring a pattern of a mask onto a substrate, wherein the transfer step is performed by the exposure apparatus according to claim 6. Description: And a microdevice.