JP2001230192A - Projection aligner and method of manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a scanning projection aligner which can obtain a pattern of high resolution by correcting the scale factor and/or distortion of a projection optical system, and a manufacturing method of a device which uses the projection aligner. SOLUTION: In a projection aligner, a pattern on a mask illuminated by a slit-shaped exposure light is projected on a photosensitive substrate with a projection optical system and scanned in a scanning direction. The projection optical system is provided with a member having a surface form of rotation asymmetry which contributes to the scale factor and/or distortion of the projection optical system regarding a direction perpendicular to the scanning direction, and a means for moving the member during scanning.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection exposure apparatus and a method of manufacturing a device, for example, manufacturing a semiconductor device such as an IC or LSI, an imaging device such as a CCD, a display device such as a liquid crystal panel, or a device such as a magnetic head. Is preferred when a pattern on a mask is scanned and exposed on a photosensitive substrate in a photolithography process for the purpose. In particular, in a state where the pattern of the slit region in the transfer pattern of the mask is projected on the substrate, the mask and the substrate are synchronously scanned with respect to the projection optical system to perform exposure.
This is suitable for application to a scanning exposure type projection exposure apparatus such as a scanning method.

[0002]

2. Description of the Related Art Conventionally, when a device such as a semiconductor device or a liquid crystal panel is manufactured using a photolithography technique, a pattern on a reticle surface is projected onto a wafer or a wafer coated with a photoresist or the like via a projection exposure system. 2. Description of the Related Art A projection exposure apparatus (stepper) that performs batch exposure transfer onto a photosensitive substrate such as a glass plate is used. On the other hand, in recent years, the miniaturization of semiconductor technology has been particularly advanced.
The resolution from 25 μm to finer patterns is the subject of discussion. Further, in order to cope with an increase in the size of a semiconductor chip pattern, it is required to transfer a reticle pattern having a larger area to each shot area on a wafer. However, it has become difficult to design and manufacture a projection optical system that suppresses various aberrations such as distortion and field curvature to a predetermined allowable value or less that can meet the demand for miniaturization over the entire effective exposure field.

For this reason, recently, a reticle and a wafer are projected on a wafer through a projection optical system with a pattern in a slit-like illumination area such as a rectangle or an arc on the reticle, and the projection magnification of the projection optical system is changed. Various types of scanning exposure type projection exposure apparatuses, such as a step-and-scan method, for sequentially exposing a reticle pattern to each shot area on a wafer while synchronously scanning in accordance with the above-mentioned method, have been proposed. This scanning exposure type projection exposure apparatus can make maximum use of the diameter of the effective exposure area of the projection optical system, and the length of the transfer pattern in the scanning direction can be longer than the diameter of the effective exposure area. Is characterized in that a pattern of a large-area reticle can be transferred onto a wafer with a small aberration.

One of the important items for obtaining a highly integrated pattern by the projection exposure technique is to always maintain the same optical performance. The projection exposure apparatus has a problem in that various aberrations fluctuate due to environmental changes such as atmospheric pressure and the exposure lens itself absorbing exposure light. In the LSI fabrication process, a mask pattern is superimposed on one wafer for exposure. At this time, 1/5 of the resolution line width required at the time of exposure is used.
A new pattern must be superposed and exposed on a pattern already formed on the wafer by the previous process with an accuracy of about 1/10. Therefore, for example, it is particularly important that the exposure magnification and the distortion performance of each exposure apparatus are stable.

In terms of exposure magnification and distortion, it is desirable that not only the performance be stable but also that it be possible to positively correct it. To create one LSI,
A lithography process such as exposure, development, and etching is repeated several tens of times. Therefore, in order to improve the productivity, it is general to arrange a plurality of exposure apparatuses on one production line, and superimpose and expose a pattern on one wafer by using the plurality of exposure apparatuses sequentially. It is. Although the exposure magnification of the exposure apparatus is adjusted to be within a certain standard, it is necessary to adjust the exposure magnification to match the exposure apparatus in the same line in order to ensure higher overlay accuracy. Furthermore, L
This is because, as the SI manufacturing process progresses, the wafer itself expands and contracts due to the influence of heat and the like during the process, and the exposure magnification to be adjusted may fluctuate.

In view of these facts, there have been proposed several inventions of a projection exposure apparatus in which magnification and distortion can be adjusted. Examples of the method include a method in which a part of a lens constituting a projection optical system proposed by the present applicant in Japanese Patent Application No. 10-201117 is made movable in the optical axis direction. 23902
There is one proposed in Japanese Patent Publication No. 3 and the like in which a part of the space of the projection optical system is variable in atmospheric pressure.

[0007]

A projection method such as a method of moving a lens in a direction of an optical axis as a mechanism for correcting magnification and distortion of a projection optical system and a method of changing a pressure in a specific space have been proposed. If an attempt is made to correct the magnification or distortion by changing a specific parameter inside the optical system, other aberrations, for example, other aberrations such as spherical aberration and coma also change. In order to stably correct these aberrations in order to stabilize various aberrations, it becomes necessary to configure many mechanisms in the projection optical system.

SUMMARY OF THE INVENTION An object of the present invention is to provide a scanning projection exposure apparatus and a method for manufacturing a device, in which optical characteristics such as apparatus magnification and / or distortion can be easily adjusted.

[0009]

According to a first aspect of the present invention, there is provided a projection exposure apparatus for projecting a pattern on a mask illuminated by slit exposure light onto a photosensitive substrate by a projection optical system and scanning in a scanning direction. In the apparatus, the projection optical system includes a member having a rotationally asymmetric surface shape that contributes to a magnification or / and a distortion of the projection optical system in a direction orthogonal to a scanning direction, and means for moving the member during the scanning. It is characterized by having.

A second aspect of the present invention is characterized in that, in the first aspect of the present invention, the member is located closest to the mask or the photosensitive substrate.

According to a third aspect of the present invention, in the first aspect of the present invention, the member rotates around the optical axis of the projection optical system during the scanning.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the member is translated in parallel to a scanning direction during the scanning.

According to a fifth aspect of the present invention, there is provided a projection exposure apparatus, wherein a pattern of a mask illuminated by slit-shaped light is projected onto a photosensitive member by a projection optical system, and the mask and the photosensitive member are irradiated with the slit-shaped light. In a projection exposure apparatus that scans in a scanning direction corresponding to a short direction, the projection optical system has an optical element having a plurality of cross-sections including an optical axis, curved surfaces different from each other, and rotatable about the optical axis. It is characterized by having.

According to a sixth aspect of the present invention, in the fifth aspect of the present invention, the curved surface is defined as X and Y in two orthogonal directions, and a is a coefficient. F (X) = aX ² f (Y) = − aY It is characterized by having the shape shown by ² .

According to a seventh aspect of the present invention, in the fifth aspect of the present invention, f (X) = aX ⁴ f (Y) = − aY, where X and Y represent two orthogonal directions of the curved surface and a is a coefficient. It is characterized by having the shape shown by ⁴ .

According to an eighth aspect of the present invention, in the invention of the fifth aspect, when the curved surface has two orthogonal directions, X and Y, and a and b are coefficients, f (X) = aX ² + bX ⁴ f (Y ) = − AY ² −bY ⁴ .

In a ninth aspect of the present invention, in accordance with the fifth aspect of the present invention, there is provided an optical element having a plurality of cross sections orthogonal to the scanning direction having curved surfaces different from each other and movable in the scanning direction. I have.

[0018] In the invention the present invention of claim 9 according to claim 10, wherein the curved surface is the two directions perpendicular to X, and Y, when the coefficient a, F (X, Y) = in a · Y · X ² It is characterized by having the shape shown.

In the projection exposure apparatus according to the present invention, the pattern of the mask illuminated by the slit-shaped light is projected onto a photosensitive member by a projection optical system, and the mask and the photosensitive member are separated by the slit-shaped light. In an exposure apparatus that scans in a scanning direction corresponding to a short direction, the projection optical system includes an optical element that has a curved surface having a plurality of cross-sectional shapes orthogonal to the scanning direction and has different curved surfaces and is movable in the scanning direction. It is characterized by having.

[0020] The invention of claim 12 is the invention of claim 11, wherein the curved surface, the two directions perpendicular to X, and Y, when the coefficient a, F (X, Y) = a · Y · X 2 It is characterized by having the shape shown by.

According to a thirteenth aspect of the present invention, in any one of the fifth to twelfth aspects, the shapes of the plurality of cross sections supply different focal lengths.

According to a fourteenth aspect of the present invention, in any one of the fifth to twelfth aspects, the shapes of the plurality of cross sections have different curvatures from each other.

According to a fifteenth aspect of the present invention, in any one of the fifth to twelfth aspects, the shapes of the plurality of cross sections are different from each other.

A sixteenth aspect of the present invention is characterized in that, in the invention of any one of the fifth to twelfth aspects, the shapes of the plurality of cross sections supply magnifications different from each other.

A seventeenth aspect of the present invention is characterized in that, in the invention of any one of the fifth to twelfth aspects, the shapes of the plurality of cross sections cause different distortions.

According to an eighteenth aspect of the present invention, in the invention according to any one of the fifth to twelfth aspects, the projection optical system includes a lens system and the optical element, and the optical element is an object side or an image side of the lens system. It is characterized by having.

In a nineteenth aspect of the present invention, in any one of the fifth to twelfth aspects, the rotational position of the optical element or the position in the scanning direction is adjusted before the scanning.

According to a twentieth aspect of the present invention, in any one of the fifth to twelfth aspects, the rotational position of the optical element or the position in the scanning direction is changed during the scanning.

According to a twenty-first aspect of the present invention, a step of exposing a wafer to a reticle pattern using the apparatus according to any one of the first to twentieth aspects and then a step of developing the exposed wafer are performed. It is characterized by including.

[0030]

Embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic view of a main part of a projection exposure apparatus according to a first embodiment of the present invention. In the present embodiment, an example is shown in which a scan-type projection exposure apparatus for manufacturing a semiconductor device corrects a projection magnification by rotating an optical member (optical characteristic correction member) around an optical axis according to scanning exposure. I have.

In FIG. 1, reference numeral 4 denotes an exposure illumination system which illuminates (with a slit opening) a reticle (mask) 1 as a first object. The exposure illumination system 4 is a light source for emitting one of an ArF excimer laser (wavelength 193 nm), a KrF excimer laser (wavelength 248 nm), a g-ray (wavelength 436 nm) and an i-ray (wavelength 265 nm), and a known optical system. System.

1 is a reticle (mask) as a first object
It is. Reference numeral 2 denotes a projection optical system such as a refraction type or a catadioptric type, and a wafer 3 (a photosensitive substrate to be exposed) which uses a circuit pattern of the reticle 1 illuminated by the exposure illumination system 4 with the light flux of the slit opening as a second object. Is projected on.

The projection optical system 2 is telecentric on both the entrance side (mask side) and the exit side (photosensitive substrate side) in order to suppress positional errors in the optical axis direction of the mask and the photosensitive substrate and fluctuations in magnification due to environmental changes. The optical system is configured. T1 is an optical unit having a function of controlling the projection magnification of the projection optical system 2, and is made of a material that transmits exposure light such as quartz or fluorite, and has an optical member (optical characteristics (A correction member) 11 and a rotation drive mechanism (drive control means) 12 thereof. The projection optical system 2 is designed so that aberration is corrected while the optical member 11 is in the optical path.

Reference numeral 5 denotes a wafer holder, and the wafer 3
Holding. Reference numeral 6 denotes a wafer stage together with a reticle stage (not shown) on which the reticle 1 is mounted.
Scanning exposure is performed by moving the projection optical system 2 at a speed ratio corresponding to the imaging magnification in synchronization with a direction orthogonal to the optical axis of the projection optical system 2 (the short axis direction of the slit opening).

Numeral 7 denotes an interference mirror for monitoring the position of the wafer stage 6 with an interferometer (not shown). The wafer 3 is positioned at a predetermined position by a wafer stage drive control system (not shown) using the interferometer mirror 7 and signals obtained from the interferometer, and scanning projection exposure is performed in that state.

The scanning projection exposure apparatus of the present embodiment is different from a normal scanning projection exposure apparatus in that an optical means T1 and a drive control means 12 are provided, and the other components are basically the same. Is the same.

In this embodiment, the optical means T1 is used for adjusting (correcting) the projection magnification (magnification) of the projection optical system 2.

In the scanning projection exposure apparatus of this embodiment, scanning exposure is performed by scanning the exposure area of the slit opening in the short axis direction of the slit opening. At this time, the magnification or distortion in the scanning direction (the short axis direction of the slit) is controlled by drive control of the mask and the wafer.

On the other hand, an optical member 11 having a surface shape that is rotationally asymmetric with respect to the major axis of the slit opening for scanning exposure, that is, a direction perpendicular to the scanning direction or distortion is disposed in the optical path, and this optical member 11 is subjected to scanning exposure. Is controlled by changing according to

Next, a description will be given using specific numerical values.

It is necessary for the projection optical system to be able to substantially correct the magnification or distortion in the long axis direction of the slit opening. For example, when the size of the exposure slit opening is set to 25 × 5 mm and a magnification change of 1 ppm is desired to occur, the positional shift amount of the optical member in the long axis direction of the slit opening occurs at a maximum of 12.5 nm, which is the distortion amount as it is. Becomes

On the other hand, the positional deviation amount of the slit opening of the optical member on the slit in the short axis direction is 2.5 nm at the maximum. However, when scanning exposure is performed, this does not cause distortion.
When the value is large, it causes a slight decrease in contrast. The effect of this decrease in contrast occurs when the amount of positional shift on the slit opening is 20 to 30 nm or more, and a magnification change of about several ppm does not affect the imaging performance.

Therefore, the optical member having the rotationally asymmetric surface shape as described above is rotated, or a displacement such as translation is given in the scanning direction, so that the sectional shape of the optical member in the major axis direction of the slit opening is continuously changed. Thus, the magnification or distortion in the long axis direction of the slit opening is continuously changed.

Since the surface of the optical member is processed, the light beam passing through the optical member is deflected by the refraction according to the sectional shape. Thereby, the imaging position of a predetermined point on the object plane is deviated in the direction perpendicular to the optical axis on the image plane, and the magnification and distortion components of the projection optical system are corrected to a shape corresponding to the cross-sectional shape. I have.

The shape of the distortion to be corrected depends on the surface shape of the optical member. The distortion shape on the image plane is a shape obtained by differentiating the surface shape of the optical member. For example, when it is desired to correct the magnification component, the surface variation f
The relationship between (x) and the position x may be processed so that f (x) = ax ² . This is essentially R
The surface may have a (spherical) shape.

Further, since the optical member is disposed between the mask and the projection optical system, preferably near the mask, the surface shape processing of the optical member and the rotation and translation of the optical member are performed by means other than magnification and distortion. Since the aberration is hardly affected, it is possible to correct the target magnification and / or distortion independently of other aberrations.

Hereinafter, a specific magnification correction method using the optical member 11 in this embodiment will be described.

The optical member 11 is expressed by f (y) = − ay ² on a surface closer to the reticle 1 based on a parallel flat plate made of a material that transmits exposure light as shown in FIG. 2, for example. The required surface shape is formed by processing the shape (aspherical surface processing).

In the first embodiment shown in FIG. 1, the optical member 11 is disposed in the optical path between the projection optical system 2 and the reticle 1 (in this embodiment, the optical member 11 is located at another position (for example, the pupil plane of the projection optical system 2). Alternatively, it may be arranged between the projection optical system 2 and the wafer 3).

Since this position is a position through which a light beam having a relatively small numerical aperture (NA) passes, when considering the deviation of the image forming position of the light beam due to the positional shift of the optical member 11, the optical member 1 is used.
1 of the light flux deflected by the surface shape f (y)
Typically, the deviation of the chief ray may be considered.

FIG. 3 is an explanatory view of the principle when light rays are deflected by the optical member 11.

The relationship between the positional deviation amount dist in the direction perpendicular to the optical axis of the optical member 11 shown in FIG. 3 and the angle change amount θ of the normal to the principal ray on the surface of the optical member 11 is dist = β · _LR (n− 1) · θ Here, _LR is the distance from the reticle 1 to the surface 11a of the optical member 11, β is the lateral magnification of the projection optical system 2, and n is the refractive index of the material of the optical member 11. Here, since θ is small, if the surface shape of the optical member 11 is f (y), θ ≒ tan θ = f (y) / dy. From this equation, the surface shape f (y) and the deviation amount dist are obtained.
The relationship f (y) = - (∫ (dist) dy) / (L R β (n-
1)), and the surface shape of the optical member 11 is differentiated to be a displacement (distortion) shape on the image plane. Therefore,
The surface shape of the optical member 11 required for generating the magnification component is a quadratic function expressed by f (y) = ay ² (Equation 1).

In order to make the magnification variable, means for changing the value of the coefficient a in the above equation is required. In the present embodiment, the coefficient a is varied by the following method.

As shown in FIG. 2, the shape of the surface 11a of the optical member 11 is such that the coefficient a in the above equation is different in two orthogonal directions. Normally, it is preferable that the sign of the coefficient a is changed in two orthogonal directions. In this case, the cross-sectional shape when two directions are x and y is expressed as f (x) = ax ² (Equation 2a) f (y) = − ay ² (Equation 2b) it can.

However, since the difference between the processing surface 11a and the reference surface is small, R is substantially the same in size but different in sign.
What is necessary is just to form the toric surface which has (spherical surface).

When the optical member 11 whose surface is processed as described above is cut along several planes passing through the center 11b, FIG.
(A), (b), and (c), the cross-sectional shape from which curvature differs is obtained.

When this is plotted as a function of the angle φ, a continuously variable curvature from + R0 to −R0 as shown in FIG. 5 can be obtained. Therefore, the rotation drive mechanism 1 shown in FIG.
By rotating the optical member 11 about the optical axis 2a (center 11b) by using 2, the magnification in the major axis direction of the slit opening in the scanning projection exposure apparatus can be changed, and an arbitrary angle is set. Thus, a desired magnification is obtained.

In FIG. 2, the optical member 11 has a rectangular shape so that the sectional shape can be easily understood. However, in practice, a circular flat plate may be processed.

As an example, in the case of a scan type projection exposure apparatus using a KrF excimer laser as a light source at a reduction ratio of 1/4 of the projection optical system, the size of the slit opening for scanning exposure is set to 25 × on the wafer. ± 5pp as 5mm
When configuring a correction mechanism having a magnification correction range of m, if the optical member 11 is formed of quartz and the distance between the reticle 1 and the optical member 11 is 10 mm, the amount of displacement from the reference plane is 52 mm from the center. Maximum displacement is about ± 0.3
A μm toroidal surface may be formed.

In this example, the slit area of the scanning exposure has a width of 5 mm in the scanning direction, but the positional deviation in the scanning direction within the slit has a maximum variation of 12.5 nm, which is substantially equal to the scanning exposure. It does not affect the baking performance at the time.

Although only one surface of the optical member 11 is toroidally processed in this embodiment, both surfaces may be processed.
In the present embodiment, the optical member 11 is surface-processed on the basis of the plane-parallel plate; However, considering processing accuracy and holding accuracy, it is most preferable to process only one surface of the parallel flat plate.

Next, a second embodiment of the present invention will be described.

In the second embodiment of the present invention, third-order distortion is corrected. FIG. 6 is a schematic diagram showing Embodiment 2 of the present invention. In the present embodiment, a distortion correcting optical unit T2 (21, 12) is applied instead of the magnification correcting optical unit T1 of the first embodiment, and the other configuration is the same as that of the first embodiment. Reference numeral 21 denotes a surface-processed optical member, and reference numeral 12 denotes a rotation mechanism that rotationally displaces the optical member 21.

FIG. 7 shows an example of the shape of the optical member 21 used in this embodiment.

In the case where the symmetric third-order distortion is corrected by the optical unit T2, the surface shape of the optical member 21 is f (x) when the absolute value is the same in two orthogonal directions and the sign is inverted. = ax ⁴ ··· (wherein 3a) f (y) = - ay 4 ··· ( wherein 3b) ^{or, f (x) = ax 2} + bx 4 ··· ( wherein 4a) f (y) = - ay ^2- by ⁴ (Equation 4b)

In the case of the shape of (Equation 3), the projection magnification correcting means (not shown in FIG. 6) (including the first embodiment of the present invention)
By combining the above, the first-order (magnification) component and the third-order component of the distortion can be corrected almost independently.

In the case of taking the shape of (Equation 4), the optical member 2
It is suitable for use in cases where it is desired to minimize the processing amount of 1 or when the minimum square magnification is not changed when correcting distortion according to the present invention.

In order to simultaneously control the magnification component in addition to the distortion, one surface of the optical member 21 is subjected to the surface processing of (Expression 3) or (Expression 4), and the other surface or a new surface is processed. The surface of the optical member may be subjected to shape processing such as (Equation 2) for controlling the magnification component.

Next, a third embodiment of the present invention will be described.

In the present embodiment, parallel displacement in the direction perpendicular to the optical axis is performed as displacement means of the optical member. FIG. 8 is a schematic diagram showing Embodiment 3 of the present invention. In the present embodiment, instead of the optical means T1 for magnification correction by rotation of the first embodiment, an optical means T3 for magnification correction by translation in the scanning direction.
The other configuration is the same as that of the first embodiment. In the optical means T3, reference numeral 31 denotes an optical member, and reference numeral 13 denotes a drive unit that drives the optical member 31 in parallel with the scanning direction of the slit opening for exposure on a plane perpendicular to the optical axis.

The optical member applied here has a cross-sectional shape in the x direction that changes continuously depending on the position of the y coordinate as shown in FIGS. 9 and 10. When this is expressed by a mathematical formula, F (x, y) = a · y · x ² (Equation 5)

Here, the x direction is taken as the major axis direction of the exposure slit A, and the optical member 31 is translated in the y direction with respect to the slit A by the driving mechanism 13 shown in FIG. The cross-sectional shape with respect to the long axis (in the longitudinal direction) can be changed.

When forming a correction mechanism having a correction range of ± 5 ppm in the case of a 25 × 5 mm slit as in the first embodiment, the optical member 31 is formed of quartz and the reticle 1
When the distance between the optical member 31 and the optical member 31 is 10 mm, the maximum displacement from the reference plane is also ± 0.3 μm.

Short axis of exposure slit, ie width 5 in scanning direction
Even at both ends of mm, there is a difference in x cross-sectional shape. When this difference is large, the contrast is reduced when scanning exposure is performed. However, the length of the optical member in the y direction is set to 200 m.
Assuming m, the maximum value of dx (variation in the x direction) in the slit is 12.5 nm, and this value does not substantially affect the imaging performance during scanning exposure.

In the first to third embodiments, the optical means for correction is provided between the mask and the projection optical system. However, the same effect can be obtained even if the optical means is provided between the projection optical system and the photosensitive substrate. .

Next, a method of manufacturing a semiconductor device using the above-described projection exposure apparatus will be described.

FIG. 11 is a flowchart for manufacturing a semiconductor device (a semiconductor chip such as an IC or LSI, or a liquid crystal panel or a CCD).

Step 1 (circuit design) in this embodiment
Now, we will design the circuit of the semiconductor device. Step 2 is a process for making a mask on the basis of the circuit pattern design.

On the other hand, in step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4
The (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by lithography using the prepared mask and wafer.

The next step 5 (assembly) is called a post-process, and is a step of forming a semiconductor chip using the wafer produced in step 4, and includes an assembly step (dicing and bonding) and a packaging step (chip encapsulation). And the like.

In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, a semiconductor device is completed and shipped (step 7).

FIG. 12 is a detailed flowchart of the wafer process in step 4 described above. First, step 11
In (oxidation), the surface of the wafer is oxidized. Step 12
In (CVD), an insulating film is formed on the wafer surface.

In step 13 (electrode formation), electrodes are formed on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. Step 15
In (resist processing), a photosensitive agent is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus to print and expose the circuit pattern of the mask onto the wafer.

In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist are removed. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

By using the manufacturing method of this embodiment, a highly integrated semiconductor device can be easily manufactured.

According to each of the embodiments described above, a scanning projection exposure apparatus and a device manufacturing method capable of favorably correcting magnification and / or distortion in a projection optical system independently of other aberrations are provided. Can be achieved.

In addition, according to the present invention, the optical member having a rotationally asymmetric cross-sectional shape can be rotated or translated in the scanning direction, and by controlling the amount of displacement, the magnification and / or the magnification of the scanning projection exposure apparatus can be improved. , Distortion can be corrected independently of other aberrations, and high-precision projection exposure can always be performed.

Further, since only a correction mechanism composed of one correction member is added to the projection optical system, there is an advantage that restrictions on design and manufacturing of the projection optical system, which tend to be complicated, can be eased.

[0089]

According to the present invention, it is possible to achieve a scanning type projection exposure apparatus and a method of manufacturing a device in which optical characteristics such as magnification and / or distortion can be easily adjusted.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a first embodiment of the present invention.

FIG. 2 is an external view exemplifying an optical characteristic correction member used in the first embodiment of the present invention.

FIG. 3 is an explanatory view showing a basic principle that light beams can be deflected by the optical member of FIG. 2;

FIG. 4 is a view showing a cross-sectional shape of the optical member of FIG. 2;

FIG. 5 is a diagram showing a change in a cross-sectional shape in an exposure slit direction when the optical member of FIG. 2 is rotated.

FIG. 6 is a schematic view showing a second embodiment of the present invention.

FIG. 7 is an exemplary external view of an optical characteristic correction member used in a second embodiment of the present invention.

FIG. 8 is a schematic view showing a third embodiment of the present invention.

FIG. 9 is an external view exemplifying an optical characteristic correction member used in Embodiment 3 of the present invention.

FIG. 10 is a view showing a cross-sectional shape of the optical member of FIG. 9;

FIG. 11 is a flowchart of a device manufacturing method according to the present invention.

FIG. 12 is a flowchart of a device manufacturing method according to the present invention.

[Explanation of symbols]

 Reference Signs List 1 mask (reticle) 2 projection optical system 3 photosensitive substrate (wafer) 4 illumination optical system 5 photosensitive substrate holder 6 wafer stage 7 interference mirror T1, T2, T3 optical means 11, 21, 31 optical member

Claims (21)

[Claims] 1. A projection exposure apparatus for projecting a pattern on a mask illuminated by slit exposure light onto a photosensitive substrate by a projection optical system and scanning in a scanning direction, wherein the projection optical system is related to a direction orthogonal to the scanning direction. A projection exposure apparatus, comprising: a member having a rotationally asymmetric surface shape that contributes to magnification and / or distortion of the projection optical system, and a unit that moves the member during the scanning. 2. The projection exposure apparatus according to claim 1, wherein said member is located closest to said mask or said photosensitive substrate. 3. The projection exposure apparatus according to claim 1, wherein said member rotates around an optical axis of said projection optical system during said scanning. 4. The projection exposure apparatus according to claim 1, wherein the member translates in parallel with a scanning direction during the scanning. 5. A pattern of a mask illuminated by slit-like light is projected onto a photosensitive member by a projection optical system, and the mask and the photosensitive member are moved in a scanning direction corresponding to a short direction of the slit-like light. In a projection exposure apparatus that performs scanning, the projection optical system includes an optical element that has a curved surface having a plurality of different cross-sections including an optical axis and is rotatable about the optical axis. apparatus. 6. The curved surface has a shape represented by f (X) = aX ² f (Y) = − aY ² where X and Y are orthogonal directions and a is a coefficient. A projection exposure apparatus according to claim 5. 7. The curved surface has a shape represented by f (X) = aX ⁴ f (Y) = − aY ⁴ where a is a coefficient and X and Y are two directions orthogonal to each other. A projection exposure apparatus according to claim 5. 8. The curved surface has a shape represented by f (X) = aX ² + bX ⁴ f (Y) = − aY ² −bY ⁴ where X and Y are orthogonal directions and a and b are coefficients. 6. The projection exposure apparatus according to claim 5, comprising: 9. The projection exposure apparatus according to claim 5, further comprising an optical element having a plurality of cross-sections orthogonal to the scanning direction and having curved surfaces different from each other and movable in the scanning direction. Wherein said curved surface is the two directions perpendicular X, and Y, when the coefficient a, claims, characterized in that it has a shape shown by F (X, Y) = a · Y · X 2 10. The projection exposure apparatus according to 9. 11. A pattern of a mask illuminated by slit-shaped light is projected onto a photosensitive member by a projection optical system, and the mask and the photosensitive member are moved in a scanning direction corresponding to a short direction of the slit-shaped light. In a scanning exposure apparatus, the projection optical system has an optical element having a curved surface having a plurality of cross-sections orthogonal to the scanning direction and different shapes from each other and movable in the scanning direction. . 12. The curved surface has two orthogonal directions, X and Y.
And then, when the coefficient a, F (X, Y) = projection exposure apparatus according to claim 11, characterized in that it has a shape shown by a · Y · X ^2. 13. The projection exposure apparatus according to claim 5, wherein the shapes of the plurality of cross sections supply different focal lengths. 14. The method according to claim 5, wherein the shapes of the plurality of cross sections have different curvatures from each other.
3. The projection exposure apparatus according to claim 2. 15. The projection exposure apparatus according to claim 5, wherein the plurality of cross sections have different aspherical shapes. 16. The method according to claim 5, wherein the shapes of the plurality of cross sections supply magnifications different from each other.
13. The projection exposure apparatus according to claim 12. 17. The apparatus according to claim 5, wherein the shapes of the plurality of cross sections cause different distortions.
13. The projection exposure apparatus according to any one of claims 12 to 12. 18. The projection optical system according to claim 5, wherein the projection optical system includes a lens system and the optical element, and the optical element is located on an object side or an image side of the lens system. Projection exposure equipment. 19. The projection exposure apparatus according to claim 5, wherein a rotation position of the optical element or a position in the scanning direction is adjusted before the scanning. 20. The projection exposure apparatus according to claim 5, wherein a rotation position of the optical element or a position in the scanning direction is changed during the scanning. 21. A device according to claim 1, comprising the steps of: exposing a wafer with a pattern of a reticle using the apparatus according to claim 1; and developing the exposed wafer. Production method.