JP2003233004A - Reflective projection optical system, exposure device, and method for manufacturing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflective projection optical system of a compact five- mirror system which is applicable to an EUV (extreme ultraviolet) lithography system and balanced between resolving power and a throughput, and to provide an exposure device and a method for manufacturing a device. <P>SOLUTION: The five mirrors which reflect light in order of a first mirror (M1), a second mirror (M2), a third mirror (M3), a fourth mirror (M4) and a fifth mirror (M5) are arranged in order from an object side to an image side so as to fundamentally form a coaxial system. A position in a height direction from the optical axis of a principal ray in each mirror is displaced in the same direction in order from the second mirror (M2) to the fifth mirror (M5). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to an exposure apparatus, and more particularly to ultraviolet rays and extreme ultraviolet rays (EUV: extr).
The present invention relates to a reflective projection optical system, an exposure apparatus, and a device manufacturing method for projecting and exposing an object to be processed such as a single crystal substrate for a semiconductor wafer and a glass substrate for a liquid crystal display (LCD) by utilizing emultraviolet light.

[0002]

2. Description of the Related Art Due to recent demands for miniaturization and thinning of electronic devices, there is an increasing demand for miniaturization of semiconductor elements mounted on the electronic devices. For example, a design rule for a mask pattern is required to form a dimensional image with a line and space (L & S) of 0.1 μm or less in a wide range, and it is expected to shift to a circuit pattern formation of 80 nm or less in the future. . L & S is an image projected on a wafer in the state where the widths of lines and spaces are the same in exposure, and is a measure showing the resolution of exposure.

A projection exposure apparatus, which is a typical exposure apparatus for semiconductor manufacturing, projects and exposes a pattern drawn on a mask or reticle (herein, these terms are used interchangeably) onto a wafer. It has a projection optical system. The resolution R (minimum dimension that can be accurately transferred) of the projection exposure apparatus is the wavelength λ of the light source and the numerical aperture (NA) of the projection optical system.
Is given by

[0004]

[Equation 1]

Therefore, the shorter the wavelength and the higher the NA, the better the resolution. In recent years, the resolution is required to have a smaller value, and increasing the NA is the limit to satisfy this requirement, and it is expected that the resolution will be improved by shortening the wavelength. Currently,
The exposure light source is a KrF excimer laser (wavelength of about 248n
m) and ArF excimer laser (wavelength about 193 nm)
It has shifted to the _{F 2} laser (wavelength: about 157 nm) from further, EUV (extreme ultravi
olet) Light is being put to practical use.

However, as the wavelength of light is shortened, the glass material through which light is transmitted is limited, so it is difficult to use many refracting elements, that is, lenses, and the projection optical system includes reflecting elements, that is, mirrors. Will be advantageous. Furthermore, when the exposure light becomes EUV light, there is no usable glass material, and it becomes impossible to include a lens in the projection optical system. Therefore, a reflective projection optical system has been proposed in which the projection optical system is composed of only a mirror (for example, a multilayer mirror).

[0007]

However, the conventional reflection type projection optical system has a problem that it is not possible to achieve a well-balanced exposure performance such as resolution and throughput, and it is not possible to provide a high quality device. More specifically, assuming that the reflectance of the multilayer film mirror is, for example, 67%, a reflection type projection optical system composed of four mirrors (hereinafter sometimes referred to as a four-mirror system). , Although a total reflectance of about 20% can be obtained,
Since the numerical aperture (NA) can be achieved only up to about 0.1, improvement in resolution cannot be expected. On the other hand, in a reflection type projection optical system composed of 6 mirrors (hereinafter sometimes referred to as a 6-mirror system), the NA can be increased to about 0.15 or more, so that the resolution can be improved. In Although,
Since the reflectivity is about 9% in total, the throughput is lowered.

For this reason, a reflection type projection optical system (hereinafter also referred to as a five-mirror system) composed of five mirrors in which the resolution and the throughput are well balanced is proposed as an intermediate number. ing. Examples of this type of five-mirror system include Japanese Patent Publication No. 2000-269132, US Pat. No. 6,072,852, and US Pat.
199,991.

[0009] Published Patent No. 2000, 269132,
NA 0.15, reduction ratio 1/4, slit width 1.7m
Examples of m and 2 mm are disclosed. However, in this embodiment, in particular, the light flux region of the third mirror is largely deviated from the optical axis and is spatially positioned above the object (reticle) of the exposure apparatus, so that the size of the entire exposure apparatus is large. It is not preferable because it leads to

US Pat. No. 6,072,852 describes NA
An example of 0.18, reduction ratio 1/4, and slit width 1.5 mm is disclosed. However, in the optical system of the design example of this publication, the object plane (mask) and the image plane (wafer) are at the same position in the optical axis direction. Therefore, since the mask stage and the wafer stage mechanically interfere with each other, it is difficult to realize the device.

US Pat. No. 6,199,991 discloses NA
An example of 0.20, a reduction ratio of 1/4, a slit width of 1.5 mm and 1 mm is disclosed. However, the optical system of the design example of this publication is disclosed in Published Patent No. 2000, No. 26913.
Similar to No. 2, in particular, since the light flux region of the third mirror is largely deviated from the optical axis and spatially positioned above the object (reticle) of the exposure apparatus, the size of the entire exposure apparatus is increased. It leads to and is not preferable.

Therefore, the present invention is applicable to an EUV lithography system, and provides a compact five-mirror type reflective projection optical system, an exposure apparatus, and a device manufacturing method in which resolution and throughput are balanced. Purpose.

[0013]

To achieve the above object, a reflection type projection optical system according to one aspect of the present invention comprises a first mirror (M1) and a second mirror (M1) in order from the object side to the image side.
The mirror (M2), the third mirror (M3), the fourth mirror (M4), and the fifth mirror (M5) in this order form five coaxial mirrors that basically form a coaxial system. The positions of the principal rays in the height direction from the optical axis in each mirror are sequentially displaced in the same direction from the second mirror (M2) to the fifth mirror (M5). Characterize. According to such a reflection type projection optical system, an image can be formed on the third mirror to the fifth mirror after the second mirror without increasing the distance from the optical axis AX of the optical system of the effective ray bundle. Therefore, the compactness of the optical system and the reduction of aberrations on each surface of the mirror can be satisfied at the same time.

In the reflective projection optical system described above, the position of the object plane in the optical axis direction is spatially defined by the first mirror (M).
1) and the third mirror (M3). Thereby, for example, only the first mirror is provided above the reticle (mask) which is the object plane of the exposure apparatus, which leads to downsizing of the exposure apparatus. The aperture stop is spatially arranged on the optical axis between the object plane and the first mirror (M1). This prevents the effective ray bundle on the mirror surface of the first mirror from being largely deviated from the optical axis. Therefore, for example, the spatial size of the first mirror above the reticle of the exposure apparatus can be set near the optical axis. Can be made smaller. An intermediate image is formed between the third mirror (M3) and the fourth mirror (M4). As a result, an intermediate image is formed by the three mirrors from the first mirror to the third mirror, and the intermediate image is reproduced on the image plane by the two mirrors of the fourth mirror and the fifth mirror. By adopting a configuration for forming an image, good aberration correction, particularly good asymmetric aberration correction can be realized. The first mirror (M1) has a concave shape, the second mirror (M2) has a concave shape, the third mirror (M3) has a convex shape, and the fourth mirror (M4) has a convex shape. 5
The mirror (M5) has a concave shape.
Thereby, good aberration correction can be realized.
At least one of the five mirrors is preferably an aspherical mirror. Further, the five mirrors are multilayer mirrors that reflect EUV light,
Light having a wavelength of m or less can be efficiently reflected.

An exposure apparatus as another aspect of the present invention is a reflection type projection optical system described above, a stage for holding a mask so as to position a mask pattern on the object plane, and a photosensitive layer on the image plane. A stage for holding the substrate for positioning, an illuminating device for illuminating the mask with arc-shaped EUV light corresponding to the arc-shaped visual field of the reflective projection optical system, and a state for illuminating the mask with the EUV light. And means for scanning each of the stages in synchronization.
According to such an exposure apparatus, the reflection type projection optical system described above is provided as a part of the components, and the NA and the slit width are increased to balance the resolution and the throughput, while holding the stage holding the mask and the substrate. It is possible to prevent mechanical interference with the rotating stage.

A device manufacturing method as still another aspect of the present invention includes the steps of exposing the object to be processed using the above-mentioned exposure apparatus, and performing a predetermined process on the exposed object to be processed. . The claims of the device manufacturing method having the same operation as the above-described operation of the exposure apparatus extend to the devices themselves which are intermediate and final products.
Further, such devices include, for example, semiconductor chips such as LSI and VSLI, CCDs, LCDs, magnetic sensors, thin film magnetic heads, and the like.

A further object or other feature of the present invention is that
It will be apparent from the preferred embodiments described below with reference to the accompanying drawings.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION A reflective projection optical system 100 and an exposure apparatus 200 according to one aspect of the present invention will be described below with reference to the accompanying drawings. However, the present invention is not limited to these examples, and each constituent element may be substituted instead as long as the object of the present invention is achieved. Here, FIG. 1 is a schematic cross-sectional view showing an exemplary form of a reflective projection optical system 100 as one aspect of the present invention and an optical path thereof. FIG. 2 is a schematic cross-sectional view showing the optical path of the principal ray for one image height in the reflective projection optical system 100 shown in FIG.

Referring to FIG. 1, a reflective projection optical system 100 of the present invention reduces a pattern on an object plane MS (eg, mask surface) onto an image plane W (eg, a surface of an object to be processed such as a substrate). An optical system for projection, which includes five mirrors M1 to M
5, the first mirror M1, the second mirror M2, the third mirror M3, the fourth mirror M4, and the fifth mirror M5 are arranged in the order in which light is reflected from the object plane MS, as shown in FIG. It is arranged.

The reflection type projection optical system 100 basically has
This is a coaxial optical system that is axially symmetric about one optical axis, and aberrations are corrected on a ring-shaped image plane centered on the optical axis. However,
In terms of aberration correction or aberration adjustment, the mirrors M1 to M5 of the reflection type projection optical system 100 do not need to be arranged so as to be completely coaxial, and some decentering may be performed to improve aberration. .

Further, the reflection type projection optical system 100, as shown in FIG. 2, has a direction of height from the optical axis of the principal ray (arrow y in the figure).
Direction) from the second mirror M2 to the fifth mirror M2.
Up to 5, the structure is sequentially displaced in the same direction. That is, in the reflective projection optical system 100, the principal ray position P1 on the second mirror M2, the principal ray position P2 on the third mirror M3, the principal ray position P3 on the fourth mirror M4,
The first to fifth mirrors M1 to M5 are arranged such that the principal ray position P4 of the fifth mirror M5 is displaced in the + y direction in the figure. In other words, the angle between the incident light flux and the reflected light ray (the direction in which the reflected light ray advances with respect to the incident light ray) on each surface from the second mirror M2 to the fifth mirror M5 is the same direction. . As a result, an image can be formed on each of the third to fifth mirrors M3 to M5 after the second mirror M2 without increasing the distance of the effective ray bundle from the optical axis AX of the optical system. The compactness of the optical system and the reduction of aberrations on each surface of the mirror can be satisfied at the same time.

Further, the reflection type projection optical system 10 of the present embodiment.
At 0, the position of the object plane MS in the optical axis direction is set to the first spatial position.
It is preferable to arrange it between the first mirror M1 and the third mirror M3. As a result, the first mirror M is located above the reticle or mask (which is used interchangeably in this application) which is the object plane MS of the exposure apparatus 200 described later.
Only 1 is left, which leads to downsizing of the exposure apparatus 200.

Even if the reticle (mask) is composed of either a reflective mask or a transmissive mask, an optical system for illuminating the mask and an alignment optical system for aligning the mask and the wafer are arranged. The degree of freedom of the exposure apparatus 200 is increased, and the exposure apparatus 200 can be made more compact.
This is advantageous for high resolution.

In addition to this, in the reflective projection optical system 100 of this embodiment, it is preferable that the aperture stop STO is spatially arranged on the optical axis between the object plane MS and the first mirror M1. . As a result, the effective light flux on the mirror surface of the first mirror M1 will not be largely deviated from the optical axis AX, so that the spatial size of the first mirror M1 above the reticle of the exposure apparatus 200 can be set to the optical axis. It can be reduced near AX, and the above-mentioned effects can be expected.

The diameter of the aperture stop STO may be fixed or variable. In the case of being variable, the NA of the optical system can be changed by changing the diameter of the aperture stop STO. By making the aperture stop STO variable, advantages such as obtaining a deep depth of focus can be obtained, which can further stabilize the image.

Furthermore, the reflection type projection optical system 10 of the present embodiment.
At 0, it is preferable to form an intermediate image between the third mirror M3 and the fourth mirror M4. That is, the first mirror M
An intermediate image is formed by the three mirrors from the first to the third mirror M3, and the intermediate image is re-formed on the image plane W by the two mirrors of the fourth mirror M4 and the fifth mirror M5. By adopting the configuration described above, it is possible to realize excellent aberration correction, particularly, excellent asymmetric aberration correction.

Further, it is more preferable that the second mirror M2 is spatially arranged between the fourth mirror M4 and the fifth mirror M5, and the second mirror M for forming the above-mentioned intermediate image.
The 2nd and 3rd mirror M3 can be arrange | positioned reasonably, and the aberration correction in the 2nd mirror M2 and the 3rd mirror M3 can be made more effective.

Further, the reflection type projection optical system 10 of the present embodiment.
In the case of 0, it is preferable that the first mirror is a concave mirror, the second mirror M2 is a concave mirror, the third mirror M3 is a convex mirror, the fourth mirror M4 is a convex mirror, and the fifth mirror M5 is a concave mirror. preferable.

In the present embodiment, each of the first to fifth mirrors M1 to M5 is composed of a concave mirror or a convex mirror, and the reflecting surface of at least one mirror has an aspherical shape, as described above. There is. From the viewpoint of aberration correction,
It is desirable that the reflecting surfaces of as many mirrors as possible have an aspherical shape, and the first mirror M1 to the fifth mirror M5.
It is most desirable to make all of the reflecting surfaces of aspherical.

In each of the first to fifth mirrors M1 to M5, the shape of the aspherical surface is represented by the general aspherical expression shown in Expression 2.

[0031]

[Equation 2]

In Expression 2, Z is the coordinate in the optical axis direction, and c
Is the curvature (the reciprocal of the radius of curvature r), h is the height from the optical axis, k
Is the conic coefficient, A, B, C, D, E, F, G, H, J, ...
.. are 4th, 6th, 8th, 10th, 12th, and 14th
Next, 16th, 18th, 20th, ... Aspherical coefficients.

Further, since the distance from the optical axis AX of the effective ray bundle on each mirror surface can be reduced by adopting the above-mentioned mirror structure, even when aberration is corrected by using each mirror surface as an aspherical surface. The amount of the aspherical surface (difference from the best fit spherical surface) can be reduced to the order of μm, which is advantageous because the accuracy can be easily obtained even in the aspherical surface processing. This also reduces the sensitivity such as eccentricity at the time of assembly and adjustment, and is advantageous for manufacturing a high-resolution exposure apparatus.

The five first mirrors M1 to M5 have a sum of Petzval terms near zero in order to flatten the image plane W of the optical system (that is, on the correction of the field curvature). , Preferably zero. That is, the sum of the refracting powers of the respective surfaces of the mirror is set to near zero. In other words, if the radii of curvature of the respective mirrors are r _{M1 to} r _M5 (the subscripts correspond to the reference numbers of the mirrors), the first mirror M1
The fifth to fifth mirrors M5 satisfy Expression 3 or Expression 4.

[0035]

[Equation 3]

[0036]

[Equation 4]

Further, a multi-layer film for reflecting EUV light is provided on the surfaces of the first to fifth mirrors M1 to M5, and the multi-layer film has a function of strengthening light.
The multilayer film applicable to the first mirror M1 to the fifth mirror M5 of the present embodiment is, for example, a Mo / Si multilayer in which molybdenum (Mo) layers and silicon (Si) layers are alternately laminated on the reflection surface of the mirror. Film or Mo layer and beryllium (Be)
A Mo / Be multilayer film in which layers are alternately laminated on the reflecting surface of the mirror can be considered. When the wavelength range around 13.4 nm is used, the mirror made of Mo / Si multilayer film has a thickness of 67.5.
% Reflectance can be obtained, and the wavelength is 11.3 nm.
When using a wavelength range in the vicinity, a mirror composed of a Mo / Be multilayer film can obtain a reflectance of 70.2%. However, the multilayer film of the present invention is not limited to the above-mentioned materials, and does not prevent the use of the multilayer film having the same action and effect as this.

A mask on which a pattern is drawn is arranged on the object surface MS. As this mask, in addition to a reflective mask provided with a multilayer film that reflects EUV light, a transmissive mask (for example, die-cutting) is used. A mask) can also be used.

[0039]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A reflective projection optical system 100 will be described below with reference to FIG. In FIG. 1, MS is a mask placed at the object plane position, W is a wafer placed at the image plane position,
STO indicates an aperture stop, and AX indicates an optical axis. In the reflection-type projection optical system 100, EU with a wavelength around 13.4 nm
The mask MS is illuminated by an illumination system (not shown) that emits V light, and the reflected light from the mask MS is sequentially reflected by the first mirror M1 (concave mirror), the second mirror M2 (concave mirror), and the third mirror M2.
Reflected by the mirror M3 (convex mirror), the fourth mirror M4 (convex mirror), and the fifth mirror M5 (concave mirror), and a reduced image of the mask pattern is formed on the wafer W arranged at the image plane position. . Further, the reflective projection optical system 100 is configured such that the position of the chief ray in the height direction from the optical axis is displaced in the same direction in order from the second mirror M2 to the fifth mirror M5.

The reflection type projection optical system 100 has a wavelength λ = 1.
3.4 nm, NA 0.16, reduction ratio ⅕, object height = 75 to 85 mm, image height = 15 to 17 mm, 2 mm
It is an arcuate image plane of width.

Table 1 shows the numerical values (radius of curvature, surface spacing, aspherical coefficient, etc.) of the optical system of the example.

[0042]

[Table 1]

Aberrations which do not include manufacturing errors (calculated at several image height points) in the embodiment are as follows: wavefront aberration = 0.040λrms, distortion = 5.8 nm (P
V) and diffraction at a wavelength of 13.4 nm
It is a limited optical system.

As described above, the present invention is a five-mirror system, but is compact, and achieves a high NA equivalent to that of the conventional six-mirror system, a relatively large slit width, and a low aberration to achieve a high resolution. This is a reflective optical system that can balance throughput.

An exposure apparatus 200 to which the reflective projection optical system 100 is applied will be described below with reference to FIG. Here, FIG. 3 is a schematic configuration diagram showing an exposure apparatus 200 having the reflective projection optical system 100. The exposure apparatus 200 is
EUV light (for example, a wavelength of 13.4) is used as illumination light for exposure.
nm) is used to perform step-and-scan exposure.

Referring to FIG. 3, the exposure apparatus 200 includes an illuminating device 210, a mask MS, a mask stage 220 on which the mask MS is mounted, a reflective projection optical system 100, and
The plate W and the wafer stage 2 on which the plate W is mounted
30 and a control unit 240. The control unit 240 is controllably connected to the illumination device 210, the mask stage 220, and the wafer stage 230.

Although not shown in FIG. 3, since EUV light has a low transmittance to the atmosphere, at least the optical path through which EUV light passes is preferably a vacuum atmosphere. In FIG. 3, X, Y, and Z represent a three-dimensional space, and the normal direction of the XY plane is the Z direction.

The illumination device 210 includes the reflection type projection optical system 10.
An illumination device that illuminates the mask MS with arc-shaped EUV light (for example, a wavelength of 13.4 nm) corresponding to an arc-shaped visual field of 0, and includes a light source (not shown) and an illumination optical system.

The mask MS is a reflective or transmissive mask on which the circuit pattern (or image) to be transferred is formed.
Is formed, and is supported and driven by the mask stage 220. The reflected or diffracted light emitted from the mask MS is reflected by the reflective projection optical system 100 and reduced and projected on the plate W.

The mask stage 220 supports the mask MS and is connected to a moving mechanism (not shown). The mask stage 220 can apply any structure known in the art. The moving mechanism (not shown) is composed of a linear motor or the like, and can move the mask MS by driving the mask stage 220 at least in the Y direction while being controlled by the control unit 240. Exposure apparatus 200
Scans the mask MS and the plate W in synchronization with each other by the control unit 240.

The reflection type projection optical system 100 includes a first mirror M1, a second mirror M2, a third mirror M3, a fourth mirror M4 and a fifth mirror M5 in the order of reflecting light from the mask MS. And the position of the chief ray in the height direction from the optical axis is sequentially displaced in the same direction from the second mirror M2 to the fifth mirror M5. Note that the reflection-type projection optical system 100 can be applied in any of the forms described above, and detailed description thereof will be omitted. Further, although the reflective projection optical system 100 shown in FIG. 1 is used in FIG. 3, such a configuration is an example, and the present invention is not limited to this.

The plate W is a wafer in this embodiment, but it includes a wide range of objects to be processed (objects to be exposed) such as a liquid crystal substrate. Photoresist is applied to the plate W. The photoresist coating process includes a pretreatment, an adhesion improver coating treatment, a photoresist coating treatment, and a prebake treatment. The pretreatment includes washing, drying and the like. The adhesion improving agent coating treatment is a surface modification treatment (that is, hydrophobic treatment by applying a surfactant) for enhancing the adhesion between the photoresist and the base, and HMDS (Hexamety).
coating or steaming an organic film such as l-disilazane). Prebaking, which is a baking (baking) step, is softer than that after development, and removes the solvent.

The wafer stage 230 supports the plate W. The wafer stage 230 uses, for example, a linear motor to move the plate W in the XYZ directions. The mask MS and the plate W are controlled by the controller 240 and are synchronously scanned. The positions of the mask stage 220 and the wafer stage 230 are monitored by, for example, a laser interferometer, and both are driven at a constant speed ratio.

The control unit 240 has a CPU and a memory (not shown) and controls the operation of the exposure apparatus 200. Control unit 2
40 is electrically connected to the illumination device 210, the mask stage 220 (that is, a moving mechanism (not shown) of the mask stage 220), and the wafer stage 230 (that is, a moving mechanism (not shown) of the wafer stage 230). The control unit 240 determines that the distance between the mask MS and the plate W is, for example,
The mask stage 220 should be about 400 mm or more.
And, to control the wafer stage 230, both stages are separated by a sufficient distance that does not cause mechanical interference.

In the exposure, the EUV light emitted from the illumination device 210 illuminates the mask MS. The EUV light reflected by the mask MS and reflecting the circuit pattern is imaged on the surface of the plate W by the reflective projection optical system 100. In this embodiment, the image plane is an arcuate (ring-shaped) image plane, and the entire surface of the mask MS is exposed by scanning the mask MS and the plate W at the speed ratio of the reduction magnification ratio.

Next, an embodiment of a device manufacturing method using the exposure apparatus 200 will be described with reference to FIGS. 4 and 5. FIG. 4 is a flow chart for explaining the manufacture of devices (semiconductor chips such as IC and LSI, LCDs, CCDs, etc.). Here, manufacturing of a semiconductor chip will be described as an example. In step 1 (circuit design), the device circuit is designed. In step 2 (mask manufacturing), a mask having the designed circuit pattern is manufactured. In step 3 (wafer manufacturing), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by a lithography technique using the mask and the wafer. Step 5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer created in Step 4, and an assembly process (dicing, bonding),
It includes steps such as packaging (chip encapsulation). In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device created in step 5 are performed. Through these steps, the semiconductor device is completed and shipped (step 7).

FIG. 5 is a detailed flowchart of the wafer process in Step 4. In step 11 (oxidation), the surface of the wafer is oxidized. Step 12 (CV
In D), an insulating film is formed on the surface of the wafer. In step 13 (electrode formation), electrodes are formed on the wafer by vapor deposition or the like. In step 14 (ion implantation),
Implant ions into the wafer. In step 15 (resist processing), a photosensitive agent is applied to the wafer. Step 16
In (exposure), the circuit pattern of the mask is exposed on the wafer by the exposure apparatus 200. In step 17 (development), the exposed wafer is developed. In step 18 (etching), parts other than the developed resist image are removed. In step 19 (resist peeling), the unnecessary resist after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer. According to such a device manufacturing method, it is possible to manufacture a higher quality device than ever before. As described above, the device manufacturing method using the exposure apparatus 200 and the resultant device also constitute one aspect of the present invention.

This embodiment is basically an optical system consisting of five mirrors. However, in order to arrange the object plane outside the optical system, the first mirror M1 and the object plane (mask surface) MS are arranged. An additional plane mirror may be placed between the two. Also,
It is also possible to further improve the performance of the optical system by giving such a flat mirror a curvature or making it an aspherical surface.

The magnification of the reflective projection optical system 100 is paraxially 1/5, but the magnification in the aberration correction region is 1
It is a value slightly deviated from / 5 times. However, by slightly shifting the paraxial magnification from ⅕, it is possible to easily achieve complete ⅕ magnification in the aberration correction region.

Further, the present invention is not limited to these embodiments, and it is possible to further improve the performance within the scope of the present invention. For example, the present invention can be applied to a reflection type optical system for ultraviolet rays other than EUV light such as i-line and excimer laser, and can also be applied to an exposure apparatus for scanning and exposing a large screen.

As described above, the present invention is a reflective optical system that can realize a large object height and image height, and can achieve diffraction-limited performance at the EUV wavelength. As a result, it is understood that even when the reflective projection optical system 100 of the present invention is applied to an EUV lithography system, mechanical interference between both stages (mask stage and wafer stage) can be prevented. It

[0062]

According to the present invention, it is possible to realize a compact reflecting optical system of five mirrors having a relatively large NA and a slit width and a small aberration, which can be used for EUV exposure, and a pattern having a fine line width. Exposure becomes possible. Also,
Since the reflection type projection optical system of the present invention can realize various object heights and image heights, it is possible to prevent interference between the mask stage and the wafer stage and provide a high quality device with good exposure performance such as throughput. can do.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing an exemplary form of a reflective projection optical system and an optical path thereof as one aspect of the present invention.

2 is a schematic sectional view showing an optical path of a chief ray with respect to one image height in the reflection type projection optical system shown in FIG.

FIG. 3 is a schematic configuration diagram showing an exposure apparatus having the reflective projection optical system shown in FIG.

FIG. 4 is a flowchart for explaining the manufacture of devices (semiconductor chips such as IC and LSI, LCDs, CCDs, etc.).

5 is a detailed flowchart of the wafer process in Step 4 shown in FIG.

[Explanation of symbols]

100 Reflective projection optical system 200 exposure equipment 210 Lighting device 220 mask stage 230 wafer stage 240 control unit M1 First mirror (concave mirror) M2 second mirror (concave mirror) M3 Third mirror (convex mirror) M4 4th mirror (convex mirror) M5 Fifth mirror (concave mirror) MS mask (object plane) W wafer (image plane) STO aperture stop Optical axis of AX optical system

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Claims (10)

[Claims] 1. A first mirror (M1), a second mirror (M2), a third mirror (M3), a fourth mirror (M4), and a fifth mirror (in order from the object side to the image side). M
Five mirrors that reflect light in the order of 5) are arranged so as to basically form a coaxial system, and the position of each principal ray of the principal ray in the height direction from the optical axis is defined as the second mirror. A reflective projection optical system characterized in that (M2) to the fifth mirror (M5) are sequentially displaced in the same direction. 2. The position of the object plane in the optical axis direction is spatially defined by the first mirror (M1) and the third mirror (M3).
The reflection type projection optical system according to claim 1, wherein 3. A reflection type projection optical system according to claim 2, wherein an aperture stop is spatially arranged on the optical axis between the object plane and the first mirror (M1). 4. The reflection type projection optical system according to claim 1, wherein an intermediate image is formed in the middle of the third mirror (M3) and the fourth mirror (M4). 5. The first mirror (M1) has a concave shape,
The second mirror (M2) is concave, the third mirror (M3) is convex, the fourth mirror (M4) is convex, and the fifth mirror (M5) is concave. The reflection type projection optical system according to claim 1. 6. The reflection type projection optical system according to claim 1, wherein at least one of the five mirrors is an aspherical mirror. 7. The EUV (extr)
The reflection type projection optical system according to claim 1, wherein the reflection type projection optical system is a multilayer film mirror that reflects an emultraviolet light. 8. The wavelength of the light is EUV of 20 nm or less.
The reflection type projection optical system according to claim 1, which is light. 9. The reflective projection optical system according to claim 1, a stage for holding the mask so as to position a pattern of the mask on the object plane, and a photosensitized on the image plane. A stage for holding a substrate to position a layer, an illuminating device for illuminating the mask with arc-shaped EUV light corresponding to the arc-shaped field of view of the reflective projection optical system, and a state for illuminating the mask with the EUV light And an exposure apparatus having means for synchronously scanning the respective stages. 10. A device manufacturing method, comprising: exposing an object to be processed using the exposure apparatus according to claim 9; and performing a predetermined process on the exposed object to be processed.