JPH07263322A - Stepper using extreme ultraviolet rays - Google Patents

Abstract

PURPOSE:To provide a stepper which uses extreme ultraviolet rays and is not deteriorated in exposure accuracy, exposure throughput, and working efficiency. CONSTITUTION:Differential exhaust mechanisms 1 and thin film windows 2 are respectively provided between a space in which a lighting optical system 4 using extreme ultraviolet rays for exposure is positioned and another space in which a mask 5 on which an exposure mask is drawn is provided, between a space in which image forming optical systems 6a and 6b which form the images of the exposure pattern by reduction-projecting the pattern are arranged and the space in which the mask is provided, and between a space in which a wafer 7 having a surface on which the image of the pattern is formed by reduction projection and the space in which the optical systems 6a and 6b are arranged so as to separate the spaces from each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to lithography technology and
In the field of micromechanics, the present invention relates to an extreme ultraviolet reduction projection exposure apparatus used for pattern formation in the manufacture of ULSI such as semiconductor elements and quantum effect elements, or in the manufacture of parts for micro robots.

[0002]

2. Description of the Related Art In an exposure technique for forming a pattern by exposing a vacuum ultraviolet ray such as a laser plasma, a solid-state laser, an SR light source, or an extreme ultraviolet ray such as an X-ray, the transfer performance is influenced by the accuracy of a mask. In view of the drawbacks of the method, adoption of a reduction projection exposure method in which an enlarged mask pattern is reduced and transferred to a sample such as a wafer has been studied.

[0003]

In such an extreme ultraviolet reduction projection exposure method (EUVL), the exposure wavelength is 4.4-1.
Since it is in the region of 00 nm, light is significantly attenuated by the atmosphere and He on the optical path, and as shown in FIG. 3, the illumination optical system 4, the mask 5, the imaging optical systems 6a and 6b, the sample 7 such as a wafer, etc. It is necessary to maintain a high vacuum in the chamber 3 for the exposure configuration including.

When heat is generated in the mask 5 and the sample 7 by the irradiation of the extreme ultraviolet rays having such a high energy level, there is no escape area for the heat because it is in a high vacuum, the temperature of these is increased, and the exposure accuracy is improved. Will be reduced.

Further, when the mask 5 and the sample 7 are replaced, the mask 5 and the sample 7 are once opened to the atmospheric pressure and then replaced, so that it is necessary to evacuate to a high vacuum region again after the work is completed, which lowers the work efficiency. . Further, the resist or the like applied to the pattern image forming surface of the sample 7 is decomposed by the irradiation of each exposure described above, and the decomposed products reach and adhere to the image forming optical systems 6a and 6b, so that the optical system is contaminated. As a result of the decrease in reflectance and the decrease in illuminance, the exposure throughput decreases.

[0006] Usually, exposure of a wafer is performed by exposing a part of the wafer in a certain area called an exposure field, moving the wafer to a predetermined position, exposing another area, and repeating the movement of the wafer again in sequence. To expose. However, since the imaging optical system is gradually contaminated and the illuminance decreases, it becomes difficult to give the same exposure amount to the resist for each exposure field within the wafer surface or for each wafer.

When SR light is used as a light source, SR
There is a problem that the position of the light emitting point changes with time, the SR light does not reach a predetermined position of the optical system downstream from the light emitting point, and the exposure illuminance varies.

On the other hand, in the reduction projection exposure method, the imaging optical system 6
Since a reflection optical system is used for a and 6b, it is necessary to perform highly accurate synchronous scanning of the mask 5 and the sample 7 with respect to the annular illumination area by the synchronous scanning mechanism 8 in order to widen the exposure area. However, the above-mentioned synchronous scanning in a high vacuum is extremely difficult, and the exposure accuracy is further deteriorated.

The present invention was conceived in view of the above problems of the prior art, and proposes a structure of an extreme ultraviolet reduction projection exposure apparatus which does not deteriorate the exposure accuracy, exposure throughput, and work efficiency. To do.

[0010]

Therefore, the construction of the extreme ultraviolet reduction projection exposure apparatus of the present invention is as shown in FIG.
An imaging optical system for forming an image while reducing and projecting the exposure pattern between the space in which the illumination optical system 4 using extreme ultraviolet rays is arranged for each exposure and the space in which the mask 5 on which the exposure pattern is drawn is arranged. A differential is provided between the space in which 6a and 6b are arranged and the mask arrangement space, and between the space in which the sample 7 having the image plane of the above pattern by reduced projection is arranged and the image formation optical system arrangement space. At least one of the exhaust mechanism 1 and the thin film window 2 is provided, and the space between these spaces is separated as a basic feature.

In addition to the above configuration, a configuration is further proposed in which a synchronous scanning mechanism 8 for performing highly accurate synchronous scanning of the mask 5 and the sample 7 with respect to the annular illumination area in order to widen the exposure area is also proposed.

When the atmospheric pressure changes, the attenuation rate of each exposure in the optical path in the atmosphere changes, so that the intensity of each exposure reaching the sample surface changes. Therefore, as shown in FIG. 2, the pressure sensors 13a and 13b are provided in the mask disposition space and / or the sample disposition space, and the pressure sensor 13a,
By controlling the 13b and the synchronous scanning mechanism 8 in cooperation with each other, the moving speed of the mask 5 and the sample 7 is changed according to the fluctuation of the atmospheric pressure to reach the entire surface of one sample or the irradiation surface between two or more samples. The intensity of each exposure to be performed is always controlled to be the same, and with such a configuration, the exposure amount can be controlled with higher accuracy.

On the other hand, in addition to the above configuration, as shown in FIG. 2, the beam monitor 11a (11b, 11c,
11d is also the same), and the beam monitor 1
By controlling the 1a and the illumination optical system 4a and / or 4b in cooperation with each other, it is possible to follow the temporal change of the position of the SR light emitting point, and the exposure illuminance can be stabilized.

Further, as shown in the figure, at least a pair of beam monitors 11b, 11c, 11 are provided in front of and behind the thin film window 21.
By providing d, it is possible to confirm the stain or damage of the thin film window 21 by examining the change over time of the light intensity difference before and after the thin film window 21, and it is possible to accurately know the replacement time of the thin film window 21.

In addition, when the windowed gate valve 10 is provided before and after the thin film window 21, the front and rear gate valves 10 are closed when the thin film window 21 is replaced, so that only the space near the thin film window 21 is at atmospheric pressure. Will be able to.

With respect to these configurations, the mask placement space and the sample placement space may be set as the same space, and the illumination light system placement space and the imaging optical system placement space may be set as the same space. May be assembled.

[0017]

In these configurations, between the illumination optical system arrangement space and the mask arrangement space, between the image forming optical system arrangement space and the mask arrangement space, and between the sample arrangement space and the image forming optical system arrangement space. At the same time, an atmosphere or atmosphere pressure separating mechanism constituted by the differential evacuation mechanism 1 and the thin film window 2 is introduced. Therefore, the illumination optical system arrangement space and the imaging optical system arrangement space are kept in a high vacuum by the exhaust systems 9a and 9b, while the mask arrangement space and the sample arrangement space can be adjusted to atmospheric pressure or reduced pressure atmosphere. It is possible to illuminate the mask 5 and expose the sample 7 in such an atmosphere.

In the above construction, the illumination optical system 4 is constructed so that the transmission / reflection used when exposing to vacuum ultraviolet rays or extreme ultraviolet rays such as X-rays obtained from laser plasma, solid-state laser, SR light source, or the like. It is composed of an optical system such as a mold, and includes, for example, a two-surface aspherical reflection optical system in which a convex surface and a concave surface are combined. As the structure of the mask 5, a structure corresponding to each of the above exposures is used. For example, if each exposure has a wavelength of 5 nm, chromium (Cr) and carbon (C) are respectively 1.2 nm and 1. 2 on the SiC substrate. A mask pattern is used in which a multilayer film having a thickness of 2 nm and several tens of layers alternately stacked is formed and the multilayer film is processed by dry etching to form a mask pattern. The image forming optical systems 6a and 6b are configured as a reflection optical system having a small attenuation factor for each exposure (for example, for 5 nm exposures, Cr of 1.2 nm and C of 1.2 nm are alternately formed in hundreds and tenths. A multilayer film in which each layer is laminated is used for vapor deposition) is used, and the mask pattern can be reduced and projected by a combination of a convex surface configuration and a concave surface configuration. As the structure of the sample 7, a structure such as a semiconductor wafer is used, and a resist [eg, AZ-PN100 for SR light (manufactured by Hoechst Co.) for SR light] or the like is coated on the image forming surface side thereof. There is. A known differential pumping structure can be used for the differential pumping mechanism 1. For example, a plurality of narrow spaces are provided in the optical path direction, and a rotary pump or a turbo molecule is connected to these spaces by slits or tubes on the other side. A configuration in which a vacuum pump such as a pump, a cryopump, and an ion pump is installed can be used. The structure of the thin film window 2 is made of a material capable of transmitting exposure light and having a transmission attenuation factor as low as possible (for example, a diamond thin film or a laminated film of diamond and amorphous carbon when the exposure wavelength is 5 nm), and is sufficiently exposed on the optical path. When the area is set to the extent possible, it is preferable that the area be as thin as possible to withstand the differential pressure between the two surfaces.

[0019]

EXAMPLE An example of the present invention will be described below. Figure 1
FIG. 3 is an apparatus schematic diagram showing the configuration of an embodiment according to the fifth invention of the present application which is an exposure apparatus for SR light reduction projection, 3 is a chamber in which the configuration of the present exposure apparatus is installed, 4 is an illumination optical system for SR light, Reference numeral 5 is an exposure mask for SR light, 6a and 6b are image forming optical systems for SR light reduction projection, 7 is a sample wafer whose resist is coated on the image forming surface, 8 is a synchronous scanning mechanism for the mask 5 and the wafer 7, and 9a. 9 and 9b respectively show the exhaust system.

In the present embodiment, between the illumination optical system arrangement space and the mask arrangement space, between the mask arrangement space and the image forming optical system arrangement space, and between the image forming optical system arrangement space and the wafer arrangement space. Each of them is provided with an atmosphere or atmosphere pressure separating mechanism constituted by the differential evacuation mechanism 1 and the thin film window 2.

In the construction of the differential evacuation mechanism 1, narrow spaces of three stages # 1 to # 3 and # 4 to # 6 are provided in the optical path direction, and the arc-shaped slits and the slits open to those spaces are formed. Connected with the subsequent pipe, vibration isolation equipment (not shown) on the other side
A rotary pump and a turbo molecular pump having the above are installed, and the rotary pump and the turbo molecular pump are provided between the illumination optical system arrangement space and the mask arrangement space and between the mask arrangement space and the imaging optical system arrangement space. Differential pumping mechanism 1 has one configuration #
It is also combined with 1 to # 3.

The structure of the thin film window 2 is composed of a laminated film of diamond and amorphous carbon, which is a material capable of transmitting light in the vicinity of 5 nm of SR light and having a transmission attenuation factor as low as possible, so that sufficient exposure is possible on the optical path. Even if the area is set to a certain level, a differential pressure is hardly applied due to the differential pumping on one side thereof, so that both §1 to §3 can be extremely thin as 100 nm.

The illumination optical system 4 is fixed from the back surface to a reflector holder (not shown) having a coolant channel. In addition, the structure consists of a mirror-finished quartz reflector,
SR light radiated from an R ring (not shown) is reflected by its mirror surface at an oblique incident angle of 4 degrees, transmitted through the thin film window 2 of §1, and the radiated light is transmitted through the differential exhaust mechanism of # 1 to # 3. The mask 5 is irradiated through the space 1. The exhaust system 9a is provided near the exit of the illumination optical system arrangement space to maintain a high vacuum that is substantially the same as the vacuum region of the SR ring.

The mask 5 is made of chromium (C
r) and carbon (C) each having a thickness of 1.2 nm and 1.2 nm are alternately laminated to form a multilayer film, and a multilayer film is processed by dry etching to form a mask pattern. There is. The mask arrangement space is filled with a He gas atmosphere and is controlled so that the atmospheric pressure is always 1 atm. The gap between the surface provided with the mask pattern and the wall surface of the # 1 differential evacuation mechanism 1 is 1 mm.

Similar to the illumination optical system 4, the image forming optical systems 6a and 6b are fixed from the back side to a reflector holder (not shown) having a coolant channel, and here, the convex surface configuration (6a) and the concave surface are provided. With the combination of the configuration (6b), reduction projection of the mask pattern can be performed. Similar to the mask 5, the imaging optical system 6 has a multilayer film in which 150 layers of Cr and C are alternately laminated, the thickness of which is adjusted so that the soft X-ray having a wavelength of 5 nm is efficiently reflected in the vicinity of direct incidence. Is vapor-deposited. The above-mentioned exhaust system 9b is provided in this image-forming optical system arrangement space, and the degree of vacuum of 10 ^-8 Torr is assisted by the configuration of the atmospheric pressure separation mechanism by the configuration of the differential exhaust mechanism 1 and the thin film window 2. Is kept at.

As the wafer 7, a silicon wafer is used, and a resist of AZ-PN 100 (manufactured by Hoechst) that is sensitive to SR light that is reduced and projected and enters is formed on the image plane side. It is spin-coated. This wafer arrangement space is also filled with a He gas atmosphere, and is similarly controlled so as to always have a pressure of 1 atmosphere. The gap between the surface on the resist application side and the wall surface of the # 6 differential evacuation mechanism 1 is 1 mm.

The synchronous scanning mechanism 8 has a mask driving device 8a and a wafer driving device 8b for performing highly accurate synchronous scanning of the mask 5 and the wafer 7 with respect to the annular illumination area in order to widen the exposure area, and also has a control system 8c. The mask 5 and the wafer 7 are moved in the same direction by the device configuration, but the mask 5 is reduced by the reduced projection by the imaging optical systems 6a and 6b.
The moving amount of the wafer 7 becomes smaller than the moving amount of. That is, the mask and the wafer move at a speed ratio according to the reduction rate.

In the configuration of this embodiment, the SR light incident from the illumination optical system 4 passes through the thin film window 2 of §1 and
The pattern forming surface of the mask 5 is irradiated through the openings provided on the wall surfaces of the differential evacuation mechanisms 1 of Nos. 3 to # 1, respectively. Then, the radiated light reflected in a state in which the contrast is different according to the mask pattern further passes through the opening of the wall surface of the differential evacuation mechanism 1 of # 1 to # 3, and the thin film window 2 of §2.
To reach the imaging optical system 6a. The radiated light is reflected by the convex reflecting mirror surface and reaches the concave reflecting mirror surface of the imaging optical system 6b on the opposite side, and during that time, the mask pattern is reduced and projected and is reflected from the concave reflecting mirror surface. After that, the radiated light passes through the thin film window 2 of §3, passes through the wall surface opening of the differential evacuation mechanism 1 of # 6 to # 4, is irradiated on the resist coating surface of the wafer 7, and the mask pattern is formed. Form an image. The exposures that reach the wafer 7 by this irradiation are X-rays having a wavelength near 5 nm. Further, during the above irradiation, the synchronous scanning mechanism 8 synchronously scans the mask 5 and the wafer 7 as described above, and moves them so as to widen the exposure amount region.

In each space of the differential evacuation mechanism 1 described above, # 1 and # 4 are 10 Torr and # 2 due to the respective differential evacuation.
And # 5 are 0.01 Torr, # 3 and # 6 are 10 ^-5 Torr
The degree of vacuum is controlled to r, and the action and the exhaust system 9b make the image forming optical system arrangement space 1 as described above.
The degree of vacuum is adjusted to 0 ^-8 Torr.

Since the arrangement space of the mask 5 and the wafer 7 is filled with the He atmosphere and controlled to 1 atm, the operation and effect peculiar to the structure of the present embodiment are controlled by the temperature of the mask 5 and the wafer 7. Higher exposure accuracy can be realized without raising, and the mask 5 by the synchronous scanning mechanism 8 can be realized.
Also, the synchronous scanning of the wafer 7 can be performed with high accuracy. Further, the attenuation of each exposure of 5 nm due to the 1 mm optical path length in the He atmosphere and the atmospheric pressure of 1 atm in the mask arrangement space and the wafer arrangement space was as small as less than 10%. Furthermore, §1 to §3
The thickness of each thin-film window 2 is almost 100 nm as described above because the differential pressure of the differential evacuation mechanism 1 of # 1 to # 6 causes almost no differential pressure, and the attenuation of each exposure is further reduced. The exposure throughput can be increased because the exposure intensity can be reduced and the exposure intensity can be increased as a result. In addition, since the vacuum degree of the image forming optical system arrangement space is maintained on the order of 10 ⁻⁸ Torr and is separated from the mask arrangement space and the wafer arrangement space by the thin film windows 2 of # 2 and # 3, the resist or the like is disassembled. There is no contamination of the optical system by objects.

Next, another embodiment of the present invention will be described.
FIG. 2 is a schematic view of an apparatus showing an embodiment configuration according to the sixth to ninth inventions of the present application which is an exposure apparatus for SR light reduction projection.
Is a chamber in which the configuration of the exposure apparatus is installed, 4a, 4b
Is an illumination optical system for SR light, 5 is an exposure mask, 6a and 6b
Is an image-forming optical system for reduction projection, 7 is a wafer as a sample whose resist is coated on the image-forming surface, 8 is a synchronous scanning mechanism for the mask 5 and the wafer 7, 9a and 9b are exhaust systems, and 10 is a gate valve with a window ( 2 shows the valve closed), 11a, 11b, 11c and 11d are beam monitors, 12 is a coordinated control system for setting the illumination optical system 4b at a predetermined position and angle, 13a and 13b. Is a pressure sensor, and 22 is a thin film filter.

In the present embodiment, between the illumination optical system arrangement space and the mask arrangement space, between the mask arrangement space and the image forming optical system arrangement space, and between the image forming optical system arrangement space and the wafer arrangement space. Each of them is provided with an atmosphere or atmosphere pressure separating mechanism constituted by the differential evacuation mechanism 1 and the thin film window 21.

In the structure of the differential evacuation mechanism 1, narrow spaces of three stages # 1 to # 3 and # 4 to # 6 are provided in the optical path direction, and the arc-shaped slits and the slits open to those spaces are formed. Connected with the subsequent pipe, vibration isolation equipment (not shown) on the other side
A rotary pump and a turbo molecular pump having the above are installed, and the rotary pump and the turbo molecular pump are provided between the illumination optical system arrangement space and the mask arrangement space and between the mask arrangement space and the imaging optical system arrangement space. Differential pumping mechanism 1 has one configuration #
It is also combined with 1 to # 3.

The structure of the thin film window 21 is made of a silicon nitride (SiN) film which is a material capable of transmitting SR light and having a transmission attenuation factor as low as possible, and has a sufficient area on the optical path for exposure. However, since differential pressure is hardly applied due to differential evacuation on one side of these, §11 is ~
Both 13 and 100 nm can be made extremely thin. The thin film filter 22 is a laminated film of a silicon nitride film having a thickness of 100 nm and a beryllium (Be) film having a thickness of 500 nm, and can be moved away from the optical axis. The beryllium (Be) film blocks visible light and ultraviolet components of SR light. The thin film filter 22 may be provided in a plurality of places of the exposure apparatus as needed.

The illumination optical systems 4a and 4b are fixed from the back side to a reflector holder (not shown) having a coolant channel, and here a platinum (Pt) reflector mirror-polished is shown. . The illumination optical system 4b sends SR light to a predetermined position of the illumination optical system 4a by reflecting the SR light emitted from the SR ring (not shown) by oblique incidence and reflecting it on its mirror surface.
A beam monitor 11a capable of detecting the position and energy intensity of SR light is installed in front of and behind the illumination optical system 4b.
The beam monitor 11a can be retracted from the optical axis. The illumination optical system 4b receives platinum light according to the position detected by the beam monitor 11a so that the SR light can be sent to a predetermined position of the illumination optical system 4a even if the emission position of the SR light changes. A linkage control system 12 is provided so that the reflecting mirror is at a predetermined position and angle. Usually, before the mask pattern is printed on the wafer as the sample coated with the resist, that is, before the exposure, the beam monitor 11
The position of the SR light is confirmed with a, and the illumination optical system 4b is adjusted so that the SR light comes to a predetermined position. Then, the beam monitor 11a is retracted from the optical axis to perform the exposure, and the beam monitor 11a is re-exposed between the exposures, for example, at the wafer exchange time.
Confirm the position of the SR light with a. By repeating these operations, it is possible to follow changes in the emission point of SR light.

The beam monitor may be installed not only before and after the illumination optical system 4b but also near the SR light emitting point, near the mask surface, near the wafer surface, and before and after the thin film window 22. For example, the beam monitors 11b, 11c, 1 are provided before and after the thin film window 22.
By providing 1d and checking the change over time in the light intensity difference before and after the thin film window, the thin film window can be confirmed for dirt and damage, and the replacement time of the thin film window can be accurately known.

The illuminating optical system 4a is composed of a mirrored quartz mirror in the drawing, and the illuminating optical system 4a reflects the SR light reflected from the illuminating optical system 4b on its mirror surface at an oblique incident angle of 4 degrees. At least, the thin film window 21 of §11 is transmitted, and the thin film 22 filter and the emitted light are passed through the spaces of the differential evacuation mechanism 1 of # 1 to # 3 to irradiate the mask 5. The exhaust system 9a is provided near the exit of the illumination optical system arrangement space to maintain a high vacuum similar to the vacuum region of the SR ring.

Gate valve 1 with windows before and after the thin film window 21
0 is placed. The window of the gate valve 10 with a window is a 5 mm thick quartz plate. Although the gate valve 10 with a window is shown in a closed state in FIG. 2, it is used in an open state during exposure. If the windowed gate valve 10 is arranged in front of and behind the thin film window 21, only the space near the thin film window 21 can be brought to atmospheric pressure when the thin film window 21 is replaced. Further, when the thin film window 21 is replaced, it is necessary to adjust the thin film window 21 and the illumination optical system 4b so that the SR light passes through a predetermined position of the thin film window 21. Since the gate valve 10 is provided, the optical axis is aligned using the visible light region of the SR light when the valve 10 is closed, and the thin film is formed so that the SR light passes through the predetermined position of the thin film window 21. The window 21 and the illumination optical system 4b can be adjusted.

The mask 5 is made of molybdenum (M
o) and silicon (Si) each having a thickness of 2.7 nm and a thickness of 4 nm, and a multilayer film in which 60 layers are alternately laminated is formed, and a 100 nm-thick gold (Au) absorber having a predetermined structure is formed on the uppermost layer thereof. The pattern is arranged. A pressure sensor 13a is installed in this mask arrangement space, filled with a He gas atmosphere, and is controlled so that the pressure is always 100 Torr. The gap between the surface provided with the mask pattern and the wall surface of the differential evacuation mechanism 1 of # 1 is 0.5 m.
m.

Like the mask 5, the imaging optical systems 6a and 6b have a wavelength of 13 nm which gives the maximum reflectance in the vicinity of direct incidence.
The thickness of each layer is adjusted so that soft X-rays in the vicinity can be adjusted.
A reflective optical system having a multilayer film formed by alternately depositing 60 layers of o and Si is used, and the illumination optical systems 4a and 4 are used.
As in the case of b, the back surface is fixed to a reflector holder (not shown) having a coolant channel, and in this embodiment, the projection of the mask pattern is reduced by the combination of the convex surface configuration (6a) and the concave surface configuration (6b). You can do it. The above-mentioned exhaust system 9b is provided in this image-forming optical system arrangement space, and the vacuum degree of 10 ^-8 Torr is also aided by the configuration of the atmospheric pressure separation mechanism by the configuration of the differential exhaust mechanism 1 and the thin film window 21. Is kept at.

As the wafer 7, a silicon wafer is used, and a resist of SAL601 (manufactured by Shipley Co., Ltd.), which is sensitive to SR light which is reduced and projected and enters, is spin-coated on the image plane side. ing. The pressure sensor 13a is also installed in this wafer arrangement space,
The gas atmosphere is filled, and similarly, it is always 100 Tor
The pressure is controlled to be r. The gap between the surface on the resist coating side and the wall surface of the # 6 differential evacuation mechanism 1 is 0.5 mm.

The synchronous scanning mechanism 8 has a control system 8c in addition to a mask driving device 8a and a wafer driving device 8b for performing highly accurate synchronous scanning of the mask 5 and the wafer 7 with respect to the annular illumination area in order to widen the exposure area. The mask 5 and the wafer 7 are moved in the same direction by the device configuration, but the mask 5 is reduced by the reduced projection by the imaging optical systems 6a and 6b.
The moving amount of the wafer 7 becomes smaller than the moving amount of. That is, the mask and the wafer move at a speed ratio according to the reduction rate.

The intensity of each exposure reaching the wafer surface depends on the moving speed of the wafer. The atmospheric pressures in the mask arrangement space and the wafer arrangement space are monitored by pressure sensors 13a and 13b. When the atmospheric pressure changes, the attenuation rate of each exposure at an optical path length of 0.5 mm in the He atmosphere changes, so that the intensity of each exposure reaching the wafer surface changes. The pressure sensors 13a and 13b are linked to the synchronous scanning control system 8c, and the moving speeds of the mask driving device 8a and the wafer driving device 8b are changed according to the fluctuation of the atmospheric pressure, so that a plurality of wafers and one of them can be moved. The intensity of each exposure that reaches the wafer surface between a plurality of chips formed on the wafer is controlled to be always the same. Further, the synchronous scanning control system 8c and the beam monitor 11 can be linked to change the moving speed of the mask and the wafer according to the intensity of each exposure. Here, the position of the beam monitor 11 is preferably as close to the wafer as possible.

In the structure of this embodiment, the SR light incident from the illumination optical system 4 passes through the thin film window 21 of §11 and is provided on the wall surfaces of the differential evacuation mechanism 1 of # 3 to # 1 respectively. The light passes through the opening, passes through the thin film filter 21, and is irradiated onto the pattern formation surface of the mask 5. Then, the radiated light reflected in a state in which the contrast differs according to the mask pattern is further used in the differential evacuation mechanism 1 of # 1 to # 3.
Through the opening of the wall surface of the above, and through the thin film window 21 of §12 to reach the image forming optical system 6a. The radiated light is reflected by the convex reflecting mirror surface and reaches the concave reflecting mirror surface of the imaging optical system 6b on the opposite side, and during that time, the mask pattern is reduced and projected and is reflected from the concave reflecting mirror surface. After that, the radiated light passes through the thin film window 21 of §13, passes through the wall surface opening of the differential evacuation mechanism 1 of # 6 to # 4, is irradiated on the resist coating surface of the wafer 7, and the mask pattern is formed. Form an image. The exposures reaching the wafer 7 by this irradiation are X-rays having a wavelength of around 13 nm. Further, during the above irradiation, the synchronous scanning mechanism 8 synchronously scans the mask 5 and the wafer 7 as described above, and moves them so as to widen the exposure amount region.

In each space of the differential evacuation mechanism 1 described above, due to the respective differential evacuation, # 1 and # 4 are 1 Torr, # 2 and # 5 are 0.01 Torr, and # 3 and # 6 are 10 ^−5. Torr
Is controlled so that the degree of vacuum becomes equal to 10 ° C., and the space for forming the imaging optical system is adjusted to 10 by the action and the exhaust system 9b.
Adjusted to ^-8 Torr vacuum.

Since the arrangement space of the mask 5 and the wafer 7 is filled with the He atmosphere and is controlled to 100 Torr, the peculiar function and effect of the structure of this embodiment are as follows.
The temperature rise of the mask 5 and the wafer 7 does not occur, and high exposure accuracy can be realized, and the synchronous scanning of the mask 5 and the wafer 7 by the synchronous scanning mechanism 8 can be performed with high accuracy. In addition, H in the mask arrangement space and the wafer arrangement space
e At the atmospheric pressure of 100 Torr, the attenuation of each exposure of 13 nm in the optical path length of 0.5 mm was as small as less than 20%.
Furthermore, the thickness of each thin film window 21 of §11 to §13 is the same as that of # 1
Since the differential evacuation of the differential evacuation mechanism # 1 to # 6 causes almost no differential pressure, the thickness can be extremely thin as 100 nm as described above, the attenuation of each exposure can be further reduced, and as a result, the exposure intensity is increased. Exposure throughput can be earned. In addition, the degree of vacuum in the arrangement space of the imaging optical system is 10 ^-8 To
Since it is kept on the rr stand and is separated from the mask arrangement space and the wafer arrangement space by the thin film windows 21 of # 2 and # 3,
There is no contamination of the optical system due to decomposed products such as resist. Further, since the position of the SR light is confirmed by the beam monitor 11a and the illumination optical system 4b is adjusted so that the SR light comes to a predetermined position, the SR to the downstream optical system due to the change of the position of the SR light emitting point is transmitted. The position of the light does not change and the illuminance does not change. Beam monitors 11b, 11c, and 11d are provided in front of and behind the thin film window 21 to check the change over time in the light intensity difference before and after the thin film window. I can know. Since the windowed gate valve 10 is arranged in front of and behind the thin film window 21, only the space near the thin film window 21 can be made atmospheric pressure when the thin film window 21 is replaced. When the thin film window 21 is replaced, the SR 10 is closed with the valve 10 in order to adjust the thin film window 21 and the illumination optical system 4b so that the SR light passes through a predetermined position of the thin film window 21.
The optical axis is set using the visible light region of the light, and the thin film window 21 and the illumination optical system 4b can be adjusted so that the SR light passes through the predetermined position of the thin film window 21. Also, pressure sensors 13a, 1
By providing 3b in cooperation with the synchronous scanning control system 8c, the moving speeds of the mask driving device 8a and the wafer driving device 8b are changed according to the fluctuation of the atmospheric pressure to reach the wafer surface for each wafer and each exposure field. The intensity of each exposure can be controlled to be always the same.

In the two embodiments, SR light was used as the light source, but it goes without saying that the same effect can be obtained even when laser plasma or solid-state laser is used as the light source.

[0048]

According to the extreme ultraviolet reduction projection exposure apparatus of the present invention, the exposure accuracy and the exposure throughput are improved, and the exposure work efficiency is not lowered due to the replacement of the mask, the sample and the thin film window. It will be.

[Brief description of drawings]

FIG. 1 is an apparatus schematic diagram showing an embodiment configuration according to a fifth invention of the present application, which is an exposure apparatus for SR light reduction projection.

FIG. 2 is an apparatus schematic diagram showing an embodiment configuration according to the sixth to ninth inventions of the present application, which is an exposure apparatus for SR light reduction projection.

FIG. 3 is a schematic diagram showing a configuration of a conventional extreme ultraviolet reduction projection exposure apparatus.

[Explanation of symbols]

 1 Differential Evacuation Mechanism 2, 21 Thin Film Window 3 Chamber 4 Illumination Optical System 5 Mask 6a, 6b Imaging Optical System 7 Wafer 8 Synchronous Scanning Mechanism 9a, 9b Exhaust System 10 Gate Valve with Window 11a, 11b Beam Monitor 11c, 11d 〃 12 Coordinated control system 13a, 13b Pressure sensor 22 Thin film filter

[Procedure amendment]

[Submission date] January 17, 1995

[Procedure Amendment 1]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 2

[Correction method] Change

[Correction content]

[Fig. 2]

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

[Figure 3]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI technical display location G03F 7/20 521 H01L 21/30 529

Claims (12)

[Claims] 1. A method for forming an image while reducing and projecting the exposure pattern between a space in which an illumination optical system using extreme ultraviolet rays is arranged for each exposure and a space in which a mask on which an exposure pattern is drawn is arranged. Differential evacuation is provided between the space in which the image optical system is arranged and the mask arrangement space, and between the space in which the sample having the image plane of the pattern formed by reduced projection is arranged and the image formation optical system arrangement space. An extreme ultraviolet reduction projection exposure apparatus characterized in that at least one of a mechanism and a thin film window is provided to separate these spaces. 2. The exposure pattern is imaged while being reduced and projected between a space in which an illumination optical system that uses extreme ultraviolet rays is arranged for each exposure and a space in which a mask on which an exposure pattern is drawn is arranged. Differential evacuation is provided between the space in which the image optical system is arranged and the mask arrangement space, and between the space in which the sample having the image plane of the pattern formed by reduced projection is arranged and the image formation optical system arrangement space. At least one of a mechanism or a thin film window is provided to separate these spaces, a beam monitor is further provided in the optical path, and the beam monitor and the illumination optical system are linked and controlled. Reduction projection exposure apparatus. 3. A method for forming an image while reducing the projection of the exposure pattern between a space in which an illumination optical system that uses extreme ultraviolet rays for each exposure is arranged and a space in which a mask on which an exposure pattern is drawn is arranged. At least a thin film window is provided between the space in which the image optical system is arranged and the mask arrangement space, and between the space in which the sample having the image plane of the pattern by reduced projection is arranged and the image formation optical system arrangement space. Is provided to separate these spaces from each other, and at least a pair of beam monitors are provided in front of and behind the thin film window. 4. A method for forming an image while reducing and projecting the exposure pattern between a space in which an illumination optical system using extreme ultraviolet rays is arranged for each exposure and a space in which a mask on which an exposure pattern is drawn is arranged. At least a thin film window is provided between the space in which the image optical system is arranged and the mask arrangement space, and between the space in which the sample having the image plane of the pattern by reduced projection is arranged and the image formation optical system arrangement space. Is provided to separate these spaces from each other, and a gate valve with a window is provided in front of and behind the thin film window. 5. A method for forming an image while reducing and projecting the exposure pattern between a space in which an illumination optical system using extreme ultraviolet rays is arranged for each exposure and a space in which a mask on which an exposure pattern is drawn is arranged. Differential evacuation is provided between the space in which the image optical system is arranged and the mask arrangement space, and between the space in which the sample having the image plane of the pattern formed by reduced projection is arranged and the image formation optical system arrangement space. At least one of a mechanism or a thin film window is provided to separate these spaces, and at the same time, a mask for the annular illumination area and a synchronous scanning mechanism of the sample are provided for expanding the exposure area. Extreme UV reduction projection exposure system. 6. A method for forming an image while reducing and projecting the exposure pattern between a space in which an illumination optical system that uses extreme ultraviolet rays is arranged for each exposure and a space in which a mask on which an exposure pattern is drawn is arranged. Differential evacuation is provided between the space in which the image optical system is arranged and the mask arrangement space, and between the space in which the sample having the image plane of the pattern formed by reduced projection is arranged and the image formation optical system arrangement space. At least one of a mechanism or a thin film window is provided to separate these spaces, and a mask for the annular illumination area and a synchronous scanning mechanism of the sample are provided for expanding the exposure area, and the mask arrangement space and / or An extreme ultraviolet reduction projection exposure apparatus, wherein a pressure sensor is provided in a sample placement space, and the pressure sensor and the synchronous scanning mechanism are linked and controlled. 7. A method for forming an image while reducing and projecting the exposure pattern between a space in which an illumination optical system using extreme ultraviolet rays is arranged for each exposure and a space in which a mask on which an exposure pattern is drawn is arranged. Differential evacuation is provided between the space in which the image optical system is arranged and the mask arrangement space, and between the space in which the sample having the image plane of the pattern formed by reduced projection is arranged and the image formation optical system arrangement space. At least one of a mechanism or a thin film window is provided to separate these spaces, and a mask for the annular illumination area and a synchronous scanning mechanism for the sample are provided to expand the exposure area, and a beam monitor is provided in the middle of the optical path. And an extreme ultraviolet reduction projection exposure apparatus, wherein the beam monitor and the illumination optical system are linked and controlled. 8. A method for forming an image while reducing and projecting the exposure pattern between a space in which an illumination optical system using extreme ultraviolet rays is arranged for each exposure and a space in which a mask on which an exposure pattern is drawn is arranged. At least a thin film window is provided between the space in which the image optical system is arranged and the mask arrangement space, and between the space in which the sample having the image plane of the pattern by reduced projection is arranged and the image formation optical system arrangement space. Is provided to separate these spaces from each other and to provide a mask for the annular illumination area and a synchronous scanning mechanism of the sample in order to widen the exposure area, and at least a pair of beam monitors are provided before and after the thin film window. Extreme UV reduction projection exposure system. 9. A method for forming an image while reducing and projecting the exposure pattern between a space in which an illumination optical system, which uses extreme ultraviolet rays for each exposure, is arranged and a space in which a mask on which an exposure pattern is drawn is arranged. At least a thin film window is provided between the space in which the image optical system is arranged and the mask arrangement space, and between the space in which the sample having the image plane of the pattern by reduced projection is arranged and the image formation optical system arrangement space. Is provided to separate these spaces and to expand the exposure area, a mask for the annular illumination area and a synchronous scanning mechanism of the sample are provided, and a gate valve with a window is provided before and after the thin film window. Characteristic extreme ultraviolet reduction projection exposure equipment. 10. The extreme ultraviolet reduction projection exposure apparatus according to claim 1, wherein the mask disposition space and the sample disposition space are the same space.
The extreme ultraviolet reduction projection exposure apparatus according to any one of items 1 to 9. 11. The extreme ultraviolet reduction projection exposure apparatus according to claim 1, wherein the illumination optical system arrangement space and the image forming optical system arrangement space are the same space. The extreme ultraviolet reduction projection exposure apparatus according to any one of items 1 to 10. 12. The extreme ultraviolet reduction projection exposure apparatus according to claim 1, wherein the mask arrangement space and / or
Alternatively, the extreme ultraviolet reduction projection exposure apparatus according to any one of claims 1 to 11, wherein the sample placement space is set to an atmospheric pressure or a reduced pressure atmosphere.