JPH0287347A - Magneto-optical recording medium for registration of exposing device - Google Patents

Abstract

PURPOSE:To increase the reading contrast of mark images by laminating a 1st magnetic layer having a high Curie temp. and low coercive force and a 2nd magnetic layer having the relatively low Curie temp. and high coercive force with respect to the 1st magnetic layer and forming the 1st magnetic layer of a rare earth transition metal alloy. CONSTITUTION:This recording medium is formed by laminating the 1st magnetic layer 23 having the high Curie point and the low coercive force and the 2nd magnetic layer 22 having the relatively low Curie temp. and the high coercive force with respect to the 1st magnetic layer 23. The 1st magnetic layer 23 consists of the rare earth transition metal alloy contg. light rare earth elements. The light rare earths are preferably selected from Ce, Pr, Nd, and Sm. The 2nd magnetic layer 22 is preferably formed of the alloy of rare earths selected from Tb and Dy and transition metals selected form Fe and Co. Exposing with low energy is executed in this way and the sufficient reading contrast of the mark images is obtd.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention projects an image of a first object onto a second object with the first object and the second object aligned in position. A projection optical system provided at an exposure position in an exposure apparatus for transferring, particularly an exposure apparatus equipped with an alignment optical system that detects the positional relationship between a first object and a second object at a position different from the exposure position. and a magneto-optical recording medium used for monitoring the distance between optical axes of the alignment optical system.

<Prior Art> This type of exposure apparatus is mainly used for printing fine patterns and main turns of semiconductor integrated circuits.

In such a device for printing semiconductor integrated circuits, in order to form a complex semiconductor integrated circuit structure, it is usually necessary to perform multiple types of printing processes in order to manufacture one semiconductor integrated circuit. The required overlay accuracy is becoming increasingly strict as patterns become finer. For this superposition, there is an off-axis method in which the position is detected using an optical system such as a microscope installed at a fixed position from the optical axis of the projection optical system.

However, there is a problem that the distance between the optical axes of the projection optical system and the alignment microscope changes over time. Accuracy must be maintained by doing this.

For this reason, the ?J? drawn on the first object? The relative positioning of the first and second objects when exposing the second object placed on the movable stage through the projection optical system is performed on the outside of the second object on the movable stage. This is done by placing a writable and erasable magneto-optical recording medium in the area.

That is, a mechanism is disposed on the movable stage to apply a magnetic field to the magneto-optical recording medium in the same direction as the optical axis of the projection optical system, that is, in a direction perpendicular to the recording medium. When monitoring the distance between the optical axes of the projection optical system and the alignment microscope, the magnetic field applying mechanism applies a magnetic field to the magneto-optical recording medium and exposes a predetermined portion to a temperature higher than the Curie temperature. to form a mark image, move the stage a certain amount to bring the image forming part under the alignment optical system, detect the position of the image, and set a reference in the alignment optical system. Sequence control is performed to measure the deviation from the position. Further, at the end of the sequence control, a reverse magnetic field is applied to the magneto-optical recording medium to erase the mark image.

The magneto-optical recording medium used in this method is a magneto-optical recording medium made of a rare earth transition metal alloy, which is used as a high-density, large-capacity memory due to its high exposure sensitivity, repeated use, durability, and resolution. suitable. When used as a memory, Gd, Tb, Dy, Ho are used as rare earths.
Heavy rare earths such as Fe, Co, etc. are used as transition metals, and a magneto-optical recording medium made of a rare earth-transition metal alloy is formed by a combination of these metals.

<Problems to be Solved by the Invention> However, the exposure amount of the projection optical system of the exposure apparatus cannot necessarily irradiate the surface of the magneto-optical recording medium with sufficient energy.

In particular, in exposure equipment that uses an excimer laser, the reversal period is long relative to the laser beam width, that is, the laser beam exposure time is short and the non-exposure time is long, so there is no heat accumulation effect (, l
) The mark image must be formed using the energy of Mother Luz.

Therefore, it is preferable to increase the exposure sensitivity of the magneto-optical recording medium so that a predetermined mark image is formed with the exposure amount of the projection optical system.For this reason, it is effective to use a composition with a low Curie temperature for the magneto-optical recording medium. It is.

However, if the composition has a low Curie temperature, the magneto-optic effect related to contrast, that is, the Kerr rotation angle, becomes small, and the polarization optical system that detects the exposed mark image in the alignment optical system has sufficient contrast to read the mark image. is difficult to obtain.

Furthermore, when the above-mentioned magneto-optical recording medium is used as a memory, the wavelength of the reproduction light is usually in the infrared region of semiconductor radar (780
~830 nm), but the wavelength of the reproducing light in the alignment optical system of the exposure device is usually a wavelength in the visible range of a halo lamp, xenon lamp, etc. Since the magneto-optic effect, that is, the Kerr rotation angle, of the medium tends to decrease as the wavelength becomes shorter, there is a problem in that the reading contrast of the mark image further deteriorates during reproduction.

The present invention has been made in view of these problems, and provides a magneto-optical recording medium for aligning an exposure device, which has high exposure sensitivity, can be exposed with low energy, and can provide sufficient reading contrast for mark images. The purpose is to

Means for Solving the Problems> The above object is to provide an illumination optical system that irradiates a first object with exposure light, a movable stage, and a first object on a second object placed on the movable stage. a projection optical system (7) that projects a pattern drawn on an object; an alignment optical system (7) that detects the relative positional relationship between the first and second objects at a position distant from the optical axis of the projection optical system; A magneto-optical recording medium used as a writable/erasable recording medium in an exposure apparatus equipped with a writable/erasable recording medium disposed on the movable stage, which has a high Keeley temperature and a low temperature. A first magnetic layer having a coercive force and a second magnetic layer having a relatively low Curie temperature and a high coercive force with respect to the first magnetic layer are laminated, and the first magnetic layer contains a light rare earth element. This is achieved by providing a magneto-optical recording medium for aligning an exposure apparatus, which is characterized by being made of a rare earth transition metal alloy containing:

<Operation> Since the first magnetic layer has a high Keely temperature and a low coercive force, a magnetic field larger than the coercive force of the first magnetic layer is applied in the direction in which the magnetization of the first magnetic layer is reversed during exposure, and the magnetic field is removed from the projection optical system. When the mark light is irradiated, the temperature of the second magnetic layer rises above the Curie temperature, and the magnetization of the first magnetic layer is reversed. When the mark light irradiation is cut off, the temperature decreases, and the magnetization of the second magnetic layer is reversed to a stable direction with respect to the first magnetic layer due to exchange coupling, following the magnetization of the first magnetic layer, and a mark image is formed. Magnetic domain! recorded as a turn.

This mark image is stably held at room temperature by the larger coercive force of the second magnetic layer, even if it is a fine mark or pattern.

That is, the coercive force and the minimum magnetic domain size that can stably exist have the following relationship, and a large coercive force is required to hold a fine mark pattern.

Here, d: Magnetic domain diameter Hc: Coercive force M8 = Saturation magnetization σ: Ploch domain wall energy When detecting the position of this mark image by the alignment optical system, the illumination light is illuminated from the first magnetic layer side and mainly focuses on the first magnetic layer. The reflected light is reflected by the first magnetic layer and detected as an image by the observation optical system, but since the first magnetic layer has a high Curie temperature, the Kerr rotation angle becomes large and the reading contrast of the mark image increases.

In addition, in rare earth transition metal alloys containing light rare earth elements, the Kerr rotation angle increases as the wavelength of the reproduction light becomes shorter, so by including light rare earth elements in the first magnetic layer, it is possible to The reading contrast is further increased.

Note that when the first magnetic layer contains a light rare earth, the saturation magnetization M8 of the first magnetic layer becomes large and the first magnetic layer becomes unstable as a perpendicularly magnetized film. Since they are stacked and magnetically exchange coupled, the magnetization of the first magnetic layer is stably maintained due to the presence of the second magnetic layer.

<Example> First, an example of an exposure apparatus to which a magneto-optical recording medium according to the present invention is applied will be described with reference to FIG. In the figure, light emitted from an illumination optical system 1 illuminates a reticle 2, and the pattern is transferred onto a wafer 4 by a projection optical system 3. The wafer 4 is fixed on a movable stage 5 placed on a surface plate 10.

The movable stage 5 can be moved in X and Y by a drive system (not shown), and the amount of movement is X.
and Y directions are monitored with l/-day length measuring instruments. In FIG. 4, the laser length measuring device 8 for the X direction appears, but the laser length measuring device for the Y direction does not appear. The height of the optical axis of this laser length measuring device 8 is set at the same height as the surface of the wafer 4 in order to eliminate Atsube's error.

Furthermore, a magneto-optical recording medium 6 is arranged outside the wafer 4 on the movable stage 5, and the height of its surface is made to match the height of the wafer 4. Further, if necessary, an adjustment mechanism is provided to match the height of the surface of the magneto-optical recording medium 6 and the height of the wafer 4. An electromagnet 7 is embedded below this magneto-optical recording medium 6, and serves as a trap so that a magnetic field can be applied in any direction above or below the optical axis direction of the projection optical system 3.

Reference numeral 9 denotes an optical system for positioning, which includes a land 14 that emits light of a wavelength that is not substantially sensitive to the resist, a beam splitter 15 for dividing the optical path, an objective lens 16, a television camera 17 for observation, and the like. The image taken by the television camera 17 is sent to the water combiator shown below, where it is processed and the position is detected.

Further, 11 is an optical system for irradiating the alignment mark 18 on the reticle, which takes out a part of the exposure light from the illumination optical system 1.
It has the function of irradiating the slit 12 and forming an image of the slit 12 on two surfaces of the reticle. The light from the illumination optical system 1 to the mark irradiation optical system 11 is guided to the shutter 1.
It is turned on/off by 3.

FIG. 5 shows an explanatory diagram of the state near the magneto-optical recording medium 6 in the conventional case, and shows a method for monitoring the distance between the optical axes of the projection optical system 3 and the alignment optical system 9 in the apparatus shown in FIG. Explain.

a) Referring to FIG. 5(, ), first, the movable stage is positioned so that the medium 6, which has been magnetized downward in advance, is directly below the projection optical system 3 and the positioning mark 18 on the reticle is imaged. Bring 5. Next, the shutter 13 is opened and the positioning mark 18 is exposed to the mark irradiation optical system 11, so that an image of the mark 18 is formed on the medium 6. At this time, if an upward magnetic field is applied, for example, by the electromagnet 7, only the portion of the medium 6 that is hit by the light absorbs the light, and the resulting heat reaches the Curie point, reversing the direction of magnetization. As a result, a portion with reversed magnetization is created in the shape of the alignment mark 18. When the exposure of the mark 18 is completed, the shutter 13 is closed.

b) Referring to FIG. 5(b), move the movable stage 5 by a vector b that is approximately the same as the vector from the exposure position of the mark 18 by the projection optical system 3 to the optical axis of the alignment optical system 9. so that the medium 6 is almost directly below the objective lens 16 of the alignment optical system. During this time, X, Y
The movement -1i1b is accurately measured by the laser sub-length device 8. Therefore, we observe the alignment marks made with the above-mentioned Stella 7"m) and detect the mark positions based on the difference in polarization state caused by the difference in the direction of magnetization. In this way, the position of the mark is measured with a laser length measuring device. The distance between the optical axes of the projection optical system 3 and the positioning optical system 9 or the deviation a from the predetermined value can be accurately determined based on the amount of movement of the stage and the detected mark position.

Based on the measured values, using the optical system 9, the alignment mark of a predetermined shot of the wafer is brought under the optical system 9, and the position of the alignment mark of the wafer with respect to the optical system 9 and the stage coordinates at that time are measured. In this case, the wafer alignment mark and the measured value of the optical system 9 in several shots may be measured using the Gui-no-9i-die method, in which each shot is measured and all the chicts on the wafer 4 are aligned. Exposure can be performed by selecting global positioning in which the stage is moved to the position of the reference grid calculated from the coordinates of the stage.

C) Referring to FIG. 5(,), when the movable stage 5 is applied with a strong downward magnetic field by the electromagnet 7 at an arbitrary position,
The entire surface of the medium 6 is magnetized downward, the marks are erased, and the medium 6 can be reused.

An example of the above sequence is shown in detail in the flowchart of FIG.

The magneto-optical recording medium according to the present invention has a high Chierly temperature (TH
) and a low coercive force (Ht, ) and a first magnetic layer made of a rare earth transition metal alloy containing a light rare earth; and a rare earth transition metal alloy having a low Keeley temperature (TL ) and a high coercive force (HH). It has a structure in which a second magnetic layer is laminated.

A typical composition of the first magnetic layer according to one embodiment can be expressed by the following formula.

HRxLR, (F・tz”z)1−x−yHowever, 0≦X
≦0.45, 0y<0.50, O<zku1. L
R is a light rare earth element with magnetic properties such as Ce and Pr.

It is preferable to choose between Nd and Sm. I(R is a heavy rare earth metal, preferably selected from one or a combination of Gd, Tb, Dy, Ha, etc.).

By including a heavy rare earth in addition to the light rare earth, the increase in saturation magnetization M due to the inclusion of the light rare earth can be suppressed, and the stability of the first magnetic layer as a perpendicularly magnetized film can be increased.

In order to improve the reproduction contrast, it is preferable to use a dxLRy (F e 11Coz) 1-
x-yHowever, O(x<0.45, o(y<o, s 0
, 0.10<z<0.85. In this composition formula, by adding the heavy rare earth element Gd, the saturation magnetization M
, it becomes stable as a perpendicular magnetization film by lowering it to an appropriate value, but to increase the stability further, Gd, Tb, Dy, Ho
etc. replacement.

It is better to use a combination.

The second magnetic layer is preferably an alloy of a rare earth selected from Tb and DY and a transition metal selected from Fs and Co. For example, TbFs, TbFeCo, D
yF@Co.

TbDyFe and the like are preferred. Tb and D7 are perpendicular magnetic anisotropy.

Since the coercive force is large, it becomes stable as a perpendicularly magnetized film and can hold fine mark patterns.

Usually, the Ti of the first magnetic layer is 300°C or higher, and the H is 1k.
oe or less, the TL of the second magnetic layer is room temperature to 250°C.

HH is preferably within a range of about 1 koe or more.

1st. The thinner the second magnetic layer is, the better in order to reduce the heat capacity and lower the exposure energy. A certain degree of thickness is required for the magnetic layer.

When the first magnetic layer is a magnetic layer made of a rare earth transition metal alloy as in the above example, the thickness is preferably about 100× to 500×. The second magnetic layer has the function of stably holding the recorded mark image due to its high coercive force,
In order to ensure that the effect of stably holding the mark image is not insufficient, it is preferable that the second magnetic layer also has a thickness of about 1001 to 500×.

1 and 2 are side views showing an example of the configuration of a magneto-optical recording medium according to the present invention.

The magneto-optical recording medium 30 shown in FIG. 1 includes a second magnetic layer 23 formed on a substrate 21, a first magnetic layer 22 laminated thereon, and a protective layer 24 formed thereon. It is something. The exposure beam or reproduction light 26 is irradiated from the protective layer 26 side.

The magneto-optical recording medium 40 shown in FIG. 2 has a substrate 21' made of a transparent material, an anti-reflection film 25 formed on the lower side thereof, and
A first magnetic layer 22 and a second magnetic layer 23 are laminated on the lower side thereof, and a protective layer 24 is formed on the lower side thereof.

The exposure beam or reproduction light 26 is applied to the substrate 21 from the substrate 21' side.
′ is transmitted through the irradiation.

Next, in the exposure apparatus shown in FIG. 4, which is an example of an exposure apparatus,
For example, the operation when the magneto-optical recording medium 30 or 40 having the configuration example shown in FIG. 1 or 2 is applied will be described.

FIG. 3 is an explanatory diagram when a magneto-optical recording medium 30 or 40 is used in place of the magneto-optical recording medium 6 of FIG. 5. Note that in this figure, the substrates 21, 21', the protective layer 241, the antireflection film 25, etc. are omitted for simplicity. In addition, the same figure (
, ) is stable when the magnetization directions of the first magnetic layer 23 and the second magnetic layer 22 are antiparallel, and FIG. Indicates a stable case.

First, before exposing a mark image to a magneto-optical recording medium, a strong downward magnetic field is generated by the electromagnet 7 to magnetize the entire magneto-optical recording medium in the same direction (see (a) and (b) in the same figure).
, (b) (b)). Note that if the magnetization directions of the first layer 23 and the second layer 22 are antiparallel and stable (see (b) in the same figure), the entire magneto-optical recording medium is heated by a predetermined means to cool the first magnetic layer. Raise it to around the Curie temperature TH of 23,
In this state, a strong downward magnetic field is applied. Then, the first magnetic layer 23 is magnetized downward. Next, when the heating is stopped and the temperature of the recording medium falls, and the temperature of the second magnetic layer 23 falls below the Chierly temperature TL, the second magnetic layer 22 changes to the first magnetic layer 2.
3, it is magnetized in a stable direction, ie upward.

Next, when moving the magneto-optical recording medium 30, 40 under the projection optical system 3 to expose a mark image, the electromagnet 7 causes a coercive force larger than that of the first magnetic layer 23 to be applied to the second magnetic layer 23.
Apply a magnetic field smaller than the coercive force of (Figure 3(, )(
a), (b) (a)). Then, when mark light is irradiated from the projection optical system, the portion irradiated with the mark light rises above the Chierly temperature (TL) of the second magnetic layer 22, and the second magnetic layer 22 changes from a ferromagnetic material to a paramagnetic material. As a result, the first magnetic layer 23 in the portion irradiated with the mark light is no longer influenced by the second magnetic layer 22, and the magnetization direction is reversed, appearing in the magnetization direction of the electromagnet 7. When the irradiation of the mark light is cut off, the temperature of the second magnetic layer 22 decreases.
However, following the magnetization direction of the first magnetic layer 23, the magnetization is reversed to a stable direction with respect to the first magnetic layer 23 due to exchange coupling. When the magnetization direction of the first magnetic layer 23 and the second magnetic layer 22 is antiparallel, it is stable (FIG. 3(,)H)), the magnetization direction is downward, and the magnetization direction of the first magnetic layer 23 and the second magnetic layer 22 is downward. If it is stable when the direction is parallel (see (b) and (a) in the same figure), the direction is upward. The magnetization of the first magnetic layer 23 is reversed, and the second magnetic layer 2
The mark image is recorded as a magnetic domain pattern by generating the magnetization of No. 2 inverted in a stable direction with respect to the first magnetic layer 23. Note that since the second magnetic layer 22 has a large coercive force, even fine mark patterns can be stably held.

When detecting the position of the mark image on the magneto-optical recording medium 30, 40 according to this embodiment, the alignment optical system 9 is used as in the conventional case.
The illumination light 14 is moved under the first magnetic layer 23.
Light up from the side. Then, the illumination light is mainly reflected off the first magnetic layer 23 side, and the mark image is detected by passing this reflected light through an analyzer such as a polarizing plate and observing the contrast between brightness and darkness. Since the magnetization direction of the part where the mark image is recorded and the other parts are opposite, the direction of the polarization plane of the reflected light is different from the direction of the polarization plane of the incident light, causing magneto-optical effect (Kerr effect). mainly the first magnetic layer 23 in the opposite direction.
The mark image can be detected by rotating the mark by a Kerr rotation angle of , and passing the reflected light through an analyzer such as a polarizing plate. Since the first magnetic layer 23 has a high Chierly temperature, the magneto-optic effect, that is, the Kerr rotation angle, increases and the mark reading contrast increases.Furthermore, since the first magnetic layer 23 contains light rare earth elements, the halogen used as the reproduction light The longer a wavelength in the visible range of a lamp, xenon lamp, etc., ie, the wavelength shorter than the wavelength in the infrared range of a semiconductor radar, is used, the larger the Kerr rotation angle becomes, and the reading contrast of the mark further increases.

Next, we will show the results of experiments conducted on a magneto-optical recording medium according to the present invention which was actually manufactured and suitable for use in an exposure apparatus.

The exposure device shown in FIG. 4 was used.

◎Specific Example 1 A magneto-optical recording medium having the structure shown in FIG. 1 was used. A St wafer is used as the substrate 21, on which TbFa is deposited at 300X as the second layer 23, and on top of which the first layer 2 is deposited.
2, NdGdFeCo was formed at 300X, and SIN was formed at 250X as the protective film 24 thereon.

The second layer 23 was formed by simultaneous sputtering of a Tb target and a Fe target to have a composition of Tb0.25''0.77 (atomic weight, the same hereinafter).

The first layer 22 has targets of Ndo, 6Gdo, 4,
Using a target of F @ o , 7 COo , s, the composition was Gd 0.08"0.12"0.56" 0.24. This medium K, exposure energy 0.5 mJ/
The alignment mark was exposed to 20 pulses of light using a KrF excimer laser with a wavelength of 248 nm and a wavelength of 248 nm. A magnetic field of 2000 a was applied upward (on the optical axis, in the direction of the light source). Thereafter, using a polarized light microscope as an alignment optical system, a contrast of 0.45 was obtained for the alignment mark under xenon lamp illumination.

As Comparative Example 1, GdO, 18"0.57"0.25 was used as the second layer.

A magneto-optical recording medium having a similar structure with TbFe as the first layer, and a GdO recording medium instead of a two-layer structure as Comparative Example 2.
, 08NdO, 12"0.56" 0.24 single layer media were prepared.

The results are as shown in Table 1, and a comparison between Example 1 and Comparative Example 1 shows that by including the light rare earth Nd in the first layer 22, the contrast during reproduction increases. In the case where only layer 1 of GdNdFeCo was used as a single layer as a recording sickle layer (Comparative Example 2), alignment marks could not be recorded.

Composition Example I GdNdFeCo,'rbFe Comparative Example I
GdFeCo,,'rbFe Comparative Example 2 GdNdF
eC.

Table 1 Contrast Required exposure ρ-10, 45 0.5 mJ/cm20.4
0.5 mυ can 2 Unable to record ◎Specific Examples 2 to 7 A magneto-optical recording medium having the structure shown in FIG. 2 was prepared. Polished quartz glass was used as the substrate 21', At203 was provided at 300X as the anti-reflection film 25 on it, and the first layer 22/second layer 23 having the compositions shown in Table 1 below were each coated at 300X. Formed. Furthermore, a 300X SIN layer was formed as a protective layer 24 thereon. The first layer 22 and the second layer 23 were created by simultaneous sputtering. Using these recording media, alignment mark exposure and xenon lamp exposure were performed under the same conditions as in Specific Example 1 (however, the exposure energy in each specific example was as shown in Table 1). When regenerated, the conotrast shown in Table 2 was obtained. Note that both exposure and reproduction were performed through the quartz glass from the quartz glass side.

◎Specific Examples 8 to 14 Magneto-optical recording media having the structure shown in FIG. 1 were prepared in the same manner as in Specific Example 1, and the materials of each layer were determined.

The thickness, forming method, etc. were also the same as in the first specific example.

The compositions of the first layer 22 and the second layer 23 were as shown in Table 3. Using these recording media, alignment marks were exposed and xenon lamps were used under the same conditions as in Specific Example 1 (however, the exposure energy in each specific example was as shown in Table 3). When I played the 3rd
The contrast shown in the table was obtained.

As is clear from the specific examples 2 to 7 and 8 to 14, the magneto-optical recording medium according to the present invention can improve the contrast during reproduction.

Note that in the configuration example shown in Figure 1, a protective layer is provided, and in the configuration example shown in Figure 2, a protective layer 8 is provided with an anti-reflection film, but by providing other reflective films, heat insulating films, etc., durability, storage stability, and recyclability can be improved. Performance such as contrast and exposure sensitivity can be improved.

An example of an exposure apparatus to which the magneto-optical recording medium according to the present invention shown in FIG. If this is done, the mark can be erased by applying a magnetic field of approximately the same strength as the magnetic field applied during mark exposure. Alternatively, the exposure apparatus may use a permanent magnet that can be turned upside down without using the electromagnet 7. Furthermore, positioning mark 1 on the reticle
The irradiation of 8 is not based on the mark irradiation optical system 11 shown in FIG.
The illumination optical system 1 may be used directly. Yet again. mark 1
As the light source 8 for irradiation, the exposure light may not be taken out from the illumination optical system 1, and another light source having substantially the same wavelength may be used. As described above, various types of exposure apparatuses can be considered to be applied to the present invention.

<Effects of the Invention> The magneto-optical storage medium for aligning an exposure apparatus according to the present invention has a first magnetic layer having a high Curie temperature and a low coercive force, and a Curie temperature relatively low with respect to the first magnetic layer. Since the first magnetic layer is made of a rare earth transition metal alloy containing a light rare earth element, the mark image can be exposed with low energy and the mark image can be Reading contrast can be increased.

[Brief explanation of drawings]

1 and 2 are side views showing a configuration example of a magneto-optical recording medium according to the present invention, and FIG. 3 is an exposure apparatus shown in FIG. FIG. 4 is an explanatory diagram of an example of an exposure apparatus to which the magneto-optical recording medium according to the present invention is applied;
FIG. 5 is an explanatory diagram of the operating state when a conventional magneto-optical recording medium is used, and FIG. 6 is a flowchart showing an example of the sequence of the exposure apparatus of FIG. 4. l: illumination optical system, 2 reticle (first object), 3: projection optical system, 4: wafer (second object), 5: movable stage, 6: magneto-optical recording medium, 7: electromagnet, 8: laser Length measuring device, 9: Optical system for alignment, 11: Optical system for mark irradiation, 21, 21: Substrate, 22: Second magnetic layer, 23: First magnetic layer, 24: Protective layer. Agent: Patent Attorney Minoru Yamashita In the case of eating 9 feet of chicks (A) Fig.

Claims (4)

[Claims] (1) An illumination optical system that irradiates a first object with exposure light, a movable stage, and a projection that projects a pattern drawn on the first object onto a second object placed on the movable stage. an optical system, an alignment optical system that detects the relative positional relationship between the first and second objects at a position distant from the optical axis of the projection optical system, and a writing/erasing system arranged on the movable stage. A magneto-optical recording medium is used as the writable/erasable recording medium in an exposure apparatus equipped with a recording medium, the magneto-optical recording medium having a first magnetic layer having a high Curie temperature and a low coercive force; A second magnetic layer having a relatively low Curie temperature and high coercive force is laminated thereon, and the first magnetic layer is made of a rare earth transition metal alloy containing a light rare earth element. Magneto-optical recording medium for device alignment. (2) The magneto-optical recording medium for exposure apparatus alignment according to claim 1, wherein the light rare earth element is selected from Ce, Pr, Nd, and Sm. (3) The magneto-optical recording medium for aligning an exposure apparatus according to claim 1 or 2, wherein the first magnetic layer also contains a heavy rare earth element. (4) The second magnetic layer is made of a rare earth element selected from Tb and Dy and a transition metal element selected from Fe and Co. 3. The magneto-optical recording medium for exposure apparatus alignment according to 3.