JP2633091B2 - Image projection method, circuit manufacturing method, and projection exposure apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image projection method and a circuit manufacturing method.
TECHNICAL FIELD The present invention relates to a new image projection method , a circuit manufacturing method, and a projection exposure apparatus suitable for forming a circuit pattern having a line width of 0.5 μm or less on a wafer. .

[0002]

2. Description of the Related Art High integration of semiconductor devices is accelerating more and more, and fine processing technology has been remarkably advanced. In particular, the optical processing technology at the center is 1MD.
The sub-micron area has been stepped on from the RAM. It is not an exaggeration to say that a typical type of optical processing apparatus is a reduction projection exposure apparatus called a stepper, and improvement in the resolution of this apparatus will play a role in the future of semiconductor devices.

Conventionally, the method used to improve the resolving power of this device has been to increase the NA of an optical system (reduction projection lens system) mainly. However, since the depth of focus of the optical system is inversely proportional to the square of NA, N
When A is increased, a problem that the depth of focus is reduced occurs. Therefore, recently, an attempt has been made to change the exposure wavelength from g-line to i-line or escimer laser light having a wavelength of 300 nm or less. This aims at the effect that the depth of focus and the resolving power of the optical system are improved in inverse proportion to the wavelength.

On the other hand, a method using a phase shift mask has emerged as a means for improving the resolving power in addition to the trend of shortening the exposure wavelength. In this method, a thin film is formed on one portion of the light transmitting portion of the mask so as to provide a phase shift of 180 degrees with respect to another portion. The resolving power RP of the stepper can be expressed by the following equation: RP = k1 .lambda. / NA. In a normal stepper, the value of the k1 factor is 0.7 to 0.8. However, the method using this phase shift mask can theoretically set the value of the k1 factor to about 0.35.

[0005]

However, many problems still remain to realize this phase shift mask. At present, the following points are at issue.

[0006] 1. Thin film formation technology for forming a phase shift film has not been established.

[0007] 2. C of circuit pattern design with phase shift film
AD development not established.

[0008] 3. Existence of a pattern to which a phase shift film cannot be provided.

4. Inspection and repair techniques for the phase shift film have not been established. As described above, there are various obstacles to actually realize the phase shift mask, and it is expected that it will take a long time to realize the phase shift mask.

[0010] Therefore, it is necessary to find a method of projecting a fine pattern image capable of obtaining a high resolving power , which is different from the phase shift mask technique having many unsolved problems.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention focuses on the fact that circuit patterns are mainly composed of vertical and horizontal patterns with the miniaturization of circuit patterns. This is a device in which an effective light source formed on a pupil plane of an image projection optical system such as a reduction projection lens system is devised. Therefore, in the case of manufacturing a semiconductor device according to the present invention, it is possible to achieve the same resolution as in the case of using a phase shift mask by improving the stepper body.

According to the image projection method of the present invention, a vertical pattern and a horizontal pattern
The image of a fine pattern with a pattern of
The projection optical system, wherein
One that extends in the vertical and horizontal directions through the center of the pupil
Intensity distribution where the light intensity of the other part is larger than that of the pair axis
Forming an effective light source on the pupil comprising:
Wherein the pair of axes are an x-axis and an y-axis of xy coordinates, and the pupil is
Is the origin of the xy coordinates, and the radius of the pupil is 1.
When the effective light source has coordinates (p,
p), (-p, p), (-p, -p), (p, -p)
It has certain four parts and the condition of 0.25 <p <0.6
It is characterized by satisfying .

Further, the circuit manufacturing method of the present invention provides a projection optical system.
The step of projecting and transferring the circuit pattern onto the substrate
A center of a pupil of the projection optical system.
Part and the center of the pupil and the length and width of the circuit pattern
Other than a pair of shafts extending in the direction of each pattern
The effective light source having an intensity distribution where the light intensity of the portion is large
Having a pattern illumination step to form on the pupil, wherein said pair of axes
The x-axis and y-axis of the xy coordinates, and the center of the pupil is
When the origin and the radius of the pupil are 1, the effective light source is
The coordinates of the respective center positions are (p, p), (-p, p), (-
p, -p) and (p, -p)
It is characterized by satisfying the condition of 0.25 <p <0.6 .

Further, the projection exposure apparatus of the present invention
A projection optical system for projecting a pattern;
And the central portion of the pupil of the projection optical system so that
From a pair of mutually orthogonal axes passing through the center of the pupil
Effective light source with an intensity distribution with high light intensity in other parts
A reticle illumination optical system for forming the pupil in the pupil,
The pair of axes are the x-axis and the y-axis of the xy coordinates, and the center of the pupil is the
When the origin of the xy coordinates and the radius of the pupil are set to 1, the effective
The coordinates of the center position of each light source are (p, p), (−p,
four parts, p), (-p, -p), (p, -p)
Satisfying the condition of 0.25 <p <0.6
Features. In the present invention, the center position is
It is the position of the center of gravity in the light intensity distribution of each part. Also book
In one embodiment of the invention, a central portion of a pupil of the projection optical system and
The light intensity at the pair of shaft portions is zero.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to facilitate understanding of the concept of the present invention, first,
The detailed pattern image formation will be described in detail.

FIG. 1 shows a state in which an image of a fine pattern 6 having a high frequency (pitch 2d is about several μm ) is projected by a projection lens system 7. The fine pattern 6 illuminated from a direction perpendicular to the surface diffracts a light beam incident thereon. The diffracted light generated at this time is a 0th-order diffracted light directed in the same direction as the traveling direction of the incident light beam, and a high-order diffracted light of, for example, ± 1 order or more directed in a direction different from the incident light beam. Of these diffracted lights, specific orders, for example, 0th and ± 1st order diffracted lights enter the pupil 1 of the projection lens system 7, are directed to the image plane of the projection lens system 7 via the pupil 1, and are minutely projected on this image plane. An image of the pattern 6 will be formed. In this type of imaging, the light component that contributes to the contrast of the image is higher-order diffracted light. For this reason, as the frequency of the fine pattern increases, higher-order diffracted light cannot be captured by the optical system, and the contrast of the image decreases. Finally, the imaging itself becomes impossible.

FIGS. 2A and 2B show a pupil 1 when the fine pattern 6 shown in FIG. 1 is formed on a conventional mask.
And the light distribution in the pupil 1 when the fine pattern 6 of FIG. 1 is formed on a phase shift mask.

In FIG. 2A, the zero-order diffracted light 3a
+ 1st-order diffracted light 3b and -1st-order diffracted light 3c are generated around the zero-order diffracted light 5a in FIG. 2B due to the effect of the phase shift film.
Only c has occurred. From the comparison between FIGS. 2A and 2B, the following two points can be mentioned as effects of the phase shift mask on the spatial frequency plane, that is, the pupil plane.

1. The frequency is 1/2 in the phase shift mask
Has been reduced to 2. No zero-order diffracted light exists in the phase shift mask.

Another point to be noted is that the distance a on the pupil plane of the ± 1st-order diffracted light in the case of the phase shift mask is different between the 0th-order light and the ± 1st-order diffracted light in the case of the conventional mask. That is, it matches the interval a. On the other hand, the light distribution at the pupil 1 is positionally identical between the conventional mask and the phase shift mask. The difference between the two is the intensity ratio of the amplitude distribution in the pupil 1. In the case of the phase shift mask shown in FIG. 2 (B), the amplitude ratio of the 0th order, + 1st order, and -1st order diffracted light is 0%. In contrast, in the case of the conventional mask shown in FIG. 2A, the amplitude ratio of the 0th-order, + 1st-order, and -1st-order diffracted lights is 1: 2 / π: 2 / π. It has become.

According to the present invention, a light distribution similar to a phase shift mask is generated in the pupil 1 without using a phase shift film.
In the present invention, when illuminating the fine pattern 6, particularly the fine pattern having a spatial frequency of about 0.5 with a k1 factor of 0.5 as described in the section of the prior art, the 0th-order diffracted light deviates from the center of the pupil 1. A pair of axes extending through the center of the pupil in the direction of the vertical and horizontal patterns and the center of the pupil so that other higher-order diffracted light is incident on the other position deviated from the center of the pupil 1. An effective light source having a light quantity distribution in which the light intensity of the other part is higher than that of each part, preferably a pair of axes extending in the direction of the vertical and horizontal patterns passing through the center of the pupil and each part of the center of the pupil An effective light source having a light intensity of almost zero is formed.

By forming such an effective light source, for example, k1
Of the 0th-order diffracted light and 1st-order diffracted light generated when illuminating a fine pattern with a factor of about 0.5, the 0th-order diffracted light and the positive or negative 1
One of the first-order diffracted lights enters the pupil 1 and the other of the positive and negative first-order diffracted lights does not enter the pupil 1.
Can be made to have a light distribution similar to that of the phase shift mask. Therefore, the same effect as in the case of using the phase shift mask can be obtained only by devising the illumination method / illumination system for illuminating the fine pattern, and the realization is easy.

In the present invention, when illumination with a unit light beam is performed, the amplitude ratio of a pair of diffracted lights in the pupil 1 becomes 1: 2 / π, which is closer to the case where a phase shift mask is used, and is more preferable 1: 1. It does not become. However, according to the analysis of the present inventor, this difference in the amplitude ratio is caused, for example, when resolving a vertical pattern of a mask, by causing light obliquely incident on the mask (fine pattern) to fall on the vertical axis of the pupil (center of the pupil). When the mask is illuminated with a pair of light beams so as to form a pair of light patterns that are symmetrical with respect to an axis extending in the direction of the vertical pattern through the mask, and a horizontal pattern of the mask is resolved, the mask (fine pattern) A pair of light patterns is formed so that a pair of light patterns that are symmetric with respect to the horizontal axis of the pupil (the axis extending in the direction of the horizontal pattern passing through the center of the pupil and perpendicular to the vertical axis of the pupil) are formed. Illuminating the mask with light has been found to be substantially compensated. Accordingly, a pair of peaks whose light intensity distributions at the pupil of the effective light source are substantially equal to each other at a position symmetrical with respect to the pupil center along a first axis extending through the pupil center and extending in a direction substantially 45 ° with the xy axis. to have, for example, perform illumination by two of the illumination light beam. or,
The light intensity distribution at the pupil of the effective light source has a pair of portions at which the intensity is substantially equal to each other at a position symmetrical with respect to the pupil center along the first axis extending in a direction passing through the pupil center and forming substantially 45 ° with the xy axis. And a symmetrical location with respect to the pupil center along a second axis extending through the center of the pupil and in a direction substantially at 90 ° to the first axis with respect to a pair of portions on the first axis and the pupil center. Illumination is performed by, for example, four illumination light beams so as to have another pair of portions having substantially the same intensity at the same position.

As a first embodiment of the present invention, the pupil 1 shown in FIG.
3 (A) and 3 (B) show the light distribution of the 0th-order diffracted light at, that is, the distribution of the effective light source on the pupil plane.

In the figure, 1 is the pupil, x is the horizontal axis of the pupil (the axis extending in the direction of the horizontal pattern passing through the center of the pupil), and y is the vertical axis of the pupil (the vertical pattern passing through the center of the pupil). 2a, 2b, 2c, and 2d indicate portions of the effective light source.

The effective light sources of the two embodiments shown here have a distribution consisting mainly of four parts. The distribution of the individual portions (light patterns) is circular. When the radius of the pupil 1 is 1.0, the center of the pupil is the coordinate origin, and the xy axis is the orthogonal coordinate axis, in the example of FIG. Parts 2a, 2b, 2c,
The centers of 2d are (0.45,0.45), (-0.45,0.45), (-0.45,-
0.45), (0.45, -0.45), and the radius of each part is 0.2
It is. In addition, in the example of FIG.
The centers of b, 2c and 2d are (0.34, 0.34), (-0.34, 0.3
4), (-0.34, -0.34), (0.34, -0.34), the radius of each part is 0.25.

When the effective light source of the present embodiment is divided into four quadrants by the xy axes set on the pupil plane, each part 2a, 2b, 2c, 2d is formed in a corresponding quadrant. Are characterized in that they are symmetrical with each other and do not overlap with each other. In this case, the x-axis and the y-axis, which are the axes separating the quadrants, coincide with the directions of the x-axis and the y-axis used when an integrated circuit pattern is designed, for example, and the vertical and horizontal patterns of the mask extend respectively. Direction.

The shape of the effective light source in this embodiment is determined by paying attention to the directionality of the vertical and horizontal patterns of the fine pattern on which the image is projected, and includes four circular portions 2a, 2a and 2b.
The feature is that the centers of b, 2c, and 2d are exactly in the ± 45 ° directions (directions in which a pair of axes extending ± 45 ° with respect to the x-axis and the y-axis and passing through the center of the pupil 1 extend). is there. In order to generate such an effective light source, four illumination light beams are obliquely incident on a fine pattern at a same incident angle along a plane of incidence orthogonal to each other.

Also, the four portions 2a, 2b, 2 of the effective light source
It is important that the intensities of c and 2d are equal to each other. If this ratio is out of order, the circuit pattern image will be deformed, for example, when the wafer to be printed is defocused. Therefore, 4
The intensities of the illumination light beams are also set equal to each other. At this time, the intensity distribution of each of the four portions 2a, 2b, 2c, and 2d has a uniform intensity distribution showing a peak value, but has a peak only at the center. Even those having a non-uniform intensity distribution can be determined appropriately. Therefore, various forms of the four illumination light fluxes are also taken according to the form of the effective light source formed on the pupil 1. For example, in this embodiment, the four parts of the effective light source are separated from each other,
Although the light pattern is not generated in places other than the respective portions, the four portions of the effective light source may be continuous via the light pattern having relatively low intensity.

The four parts 2a, 2b, 2
The distribution (shape) of c and 2d is not limited to a circle. However,
Regarding the centers of the four parts, the positions of the centers of gravity of the intensity distributions are in ± 45 ° directions with respect to the xy axis as in the embodiment shown in FIGS. Preferably, there is.

However, when aiming for a higher resolution, that is, when arranging the optimum effective light source for constructing a system having a small value of k 1, FIG. 3 (B) to FIG. 3 (A) As can be felt when the light source is moved, each portion 2a, 2a of the effective light source in each quadrant
b, 2c, and 2d are separated from the center of the pupil 1 and, accordingly, independent portions 2a, 2b,
FIGS. 3 (A) and 3 (B), in which the diameters of 2c and 2d are small, show two possible forms of effective light sources. In an actual design, effective light sources close to these two forms are used. Will be. This is because if the position of the center of gravity of each part of the effective light source is too far away from the center of the pupil 1, adverse effects such as a decrease in the amount of light may occur due to the design of the optical system. Because it comes.

According to the study of the present inventor in consideration of this point, referring to the pupil 1 and the coordinates shown in FIG. 3, a pair of portions 2a and 2c separated from each other in the first and third quadrants.
Is circular, the radius is q, and the coordinates of the center position (centroid position) of the first portion 2a and the second portion 2c are respectively (p,
When p) and (-p, -p), it was found that the following conditions should be satisfied.

0.25 <p <0.6 0.15 <q <0.3 Also , regarding the size and position of each part in the other second and fourth quadrants, the first and third quadrants are also used. Each part 2a, 2c of
Is determined by the symmetry for. That is, the second and fourth elephants
The shape of each part 2a, 2c is circular, and the radius is q
And the coordinates of each center position (center of gravity position) are (−p,
p) and (p, -p), it is better to satisfy the above conditions.
Will be. In addition, as shown in FIG.
This is when the diameter is set to 1. Further, even when each part of the effective light source is not circular, for example, triangular or quadrangular, it is preferable that the effective light source be within the range of the conditions shown here. At this time, q uses the radius of a circle circumscribing each part. The embodiment shown in FIGS. 3A and 3B has a value near the center in this condition. The values of p and q differ depending on how much fine line pattern projection is required for the optical system (illumination system / projection system) to be used.

In the stepper used so far, the peak of the effective light source exists at the center (x, y) of the pupil 1 (x, y) = (0, 0). The coherence factor-σ
A value of 0.3 or 0.5 means that there are dense effective light source distributions with a radius of 0.3 and 0.5, respectively, with the center of the pupil 1 as the center. According to the analysis of the present inventor, when an effective light source located at a position close to the pupil center, for example, when the σ value is in a range of 0.1 or less, when a defocus occurs,
It is effective to keep the contrast high mainly at a coarse line width and a line width at which the aforementioned k1 factor is 1 or more.
This defocus effect quickly worsens as the k1 factor approaches 0.5. And the k1 factor
Exceeds 0.5, in extreme cases the contrast of the image is totally lost. Currently required is k1
This is an improvement in the defocusing performance when the factor is 0.6 or less. When the k1 factor is around this, the presence of the effective light source near the center of the pupil has an adverse effect on the image formation.

On the other hand, the effective light source shown in the first embodiment has a small value of the k1 factor, and is effective in maintaining a high contrast at the time of defocus when forming an image near the k1 factor of 0.5. . The example of FIG. 3A is more outward than the example of FIG.
Since b, 2c, and 2d exist, the high-frequency characteristics are superior to those in FIG. 3 (B). Incidentally, the defocus characteristic at a portion of the effective light source away from the center of the pupil has a characteristic that the depth of focus keeps a substantially constant level up to about 1 by the k1 factor.

FIG. 4 shows the relationship between the resolving power and the depth of focus when the embodiment of FIG. 3B is applied to an i-line stepper having a projection lens system of NA 0.5, which satisfies 70% of the contrast of an optical image. The defocus in the range is an example calculated as within the depth of focus (allowable value). In the figure, a curve A shows the relationship between the resolution and the depth of focus in the conventional method (σ = 0.5) for a normal reticle, and the relationship between the resolution and the depth of focus when the curve B is shown in FIG. 3 (B). If the limit of the practically acceptable depth of focus of the stepper is set to 1.5 μm, the limit of the resolution in the conventional method is 0.52 μm, whereas in the case of FIG. The resolution has been improved. This is an improvement of about 30%, which is very large in this field. Effectively, a resolution of about 0.45 with a k1 factor can be easily achieved.

The difference between the present invention and the ring illumination method in which an effective light source is not formed at the pupil center is that the pupil 1 has an x-axis and a y-axis corresponding to the vertical and horizontal patterns of the fine pattern. Is that there is no effective light source peak. This means that by placing the peaks of the effective light source on the x and y axes,
This is because the contrast of the image largely drops, and a large depth of focus cannot be obtained. Accordingly, with respect to image projection of a fine pattern mainly composed of vertical and horizontal patterns, the present invention has achieved to obtain an image with improved image quality as compared with the ring illumination method.

In addition, the light amount (light intensity) of each main portion of the effective light source of the present invention is set to be uniform or non-uniform as in a Gaussian distribution.

FIGS. 5A, 5B and 5C are views showing a second embodiment of the present invention, in which fine patterns are formed by the method of the present invention.
1 shows a projection exposure apparatus for semiconductor manufacturing that projects an image of a semiconductor device.

In the figure, reference numeral 11 denotes an ultra-high pressure mercury lamp whose light emitting portion is set at the first focal point of an elliptical mirror, 12 denotes an elliptical mirror, 14, 21, 25 and 27 denote bending mirrors, and 15 denotes an exposure amount. Control shutter, 105 is a field lens,
16 is an interference filter for wavelength selection, 17 is a cross ND filter, 18 is a diaphragm member having a predetermined aperture, 19
Is an optical integrator whose light incident surface is set at the second focal point of the elliptical mirror 12, 20, 22 are each lens of the first imaging lens system (20, 22), and 23 is a half mirror. , 24 are masking blades having rectangular openings for regulating the illumination area on the reticle, 26 and 28 are each lens of the second imaging lens system (26, 28), and 30 is a minimum line width of about 2
a reticle on which an integrated circuit pattern composed mainly of vertical and horizontal patterns of about um is formed; 31 is a reduction projection lens system for reducing and projecting the circuit pattern of the reticle 30 to 1/5;
2 is a wafer coated with a resist, and 33 is a wafer-3
2, an XY stage for holding the wafer chuck 33; 35, a glass plate on which a light-shielding film having an opening 35a is formed in the center; and 36, an opening on the upper surface. Reference numeral 37 denotes a photoelectric converter provided in the case 36; 38, a mirror which forms a part of a laser interferometer (not shown) for measuring the amount of movement of the stage 34;
Numeral 0 is placed at a position optically equivalent to the light receiving surface of the blade 24, and the light beams emitted from the respective lenses of the integrator 19 overlap with each other, similarly to the blade 24.
A light-shielding plate having a predetermined opening, 41 is a condenser lens for condensing light from the opening of the light-shielding plate 40, and 42 is a four-divided detector.

The characteristic structure of this device is a filter 17 and a throttle member 18 placed in front of an integrator 19. As shown in FIG. 5 (B), the aperture member 18 is provided with a ring-shaped opening that blocks light near the optical axis of the apparatus, and adjusts the size and shape of the effective light source on the pupil plane of the projection lens system 31. The center of this aperture coincides with the optical axis of the device. As shown in FIG. 5 (C), the filter 17 has four ND filters arranged so as to form a cross as a whole. The intensity of light incident on four places of the ring-shaped opening is attenuated by 10 to 100%. Anyway, these four places are the projection lens system 3
A location corresponding to a portion of the pupil plane including four points on the xy axis corresponding to the vertical and horizontal patterns of the reticle 30;
The filter 17 reduces the light intensity of the effective light source on the xy axis of the pupil plane of the projection lens system 31.

The reticle 30 is held on a reticle stage (not shown). The projection lens system 31 is designed for the light of the i-line (wavelength 365 nm) selected by the filter 16. Further, the first and second imaging lens systems (20, 22, 26, 28) are provided with an integrator-19.
The light exit surface of the reticle 30 and the pupil surface of the projection lens system 31 are set to be conjugate to each other. The second imaging lens system (26, 28) Are set to be conjugate with each other.
The blade 24 is an integrated circuit pattern on the reticle 30.
Normally, four light-shielding plates each having a knife-edge-shaped tip that are independently movable so as to be able to adjust the size of the opening according to the size of the opening are used to control the entire device (not shown). The position of each light shielding plate is controlled by a command from the computer, and the size of the opening is optimized for the reticle 30 to be used.

Half mirror 23 is an integrator 19
The light reflected by the mirror 23 is incident on the lens 41 through the opening of the light shielding plate 40, and is condensed on the four-divided detector 42 by the lens 41. . The light receiving surface of the four-divided detector 42 is set so as to be optically equivalent to the pupil surface of the projection lens system 31, and projects a ring-shaped effective light source formed by the diaphragm member 18 on this light receiving surface. The four-divided detector 42 outputs a signal corresponding to the intensity of light reaching each light receiving surface for each individual detector, and opens and closes the shutter 15 by adding each output signal from the four-divided detector 42. An integrated signal for control is obtained.

The members 35 to 37 on the XY stage 34 are
The XY stage 34 is a measurement unit for checking the performance of the illumination system above the reticle 30. The XY stage 34 moves to a predetermined position when checking the illumination system, and holds the measurement unit directly below the projection lens system 31. come. In this measurement unit,
Light exiting the illumination system and reaching the image plane of the projection lens system 31 is guided to the photoelectric converter 37 through the opening 35a of the glass plate 35 and the opening of the case 36. The light receiving surface of the opening 35a is located at the image plane position of the projection lens system 31, and if necessary, a focus detection system (not shown) (a well-known sensor for detecting the height of the surface of the wafer 32) and the XY stage 34 The height of the opening 35 in the optical axis direction of the device is adjusted by using the measurement unit drive system built in the device. The glass plate 35 is attached to the case 36, and the case 36 has an opening in the center as described above. Here, the opening of the case 36 is the opening of the glass plate 35. The measuring unit is assembled so as to be shifted from the unit by a predetermined amount. The position where the opening of the case 36 is placed is a place where the NA on the image plane side of the projection lens system 31 is large and is sufficiently far from the image plane. Therefore, the light distribution on the pupil plane of the projection lens system 31 appears on the light receiving surface of the opening of the case 36 as it is. In this embodiment, this measuring unit is not used. Therefore, a description of how to use this measurement unit will be given in a later embodiment.

In this embodiment, due to the action of the filter 17 and the aperture member 18, the pupil plane of the projection lens system 31 has a ring shape as a whole and is on the xy axis corresponding to the vertical and horizontal pattern directions of the reticle 30. While forming an effective light source in which the intensity of the portion including the four points is lower than that of the other portions, the illumination system (11, 1
2, 14, 15, 105, 16, 17, 18, 19, 2,
0, 21, 22, 23, 24, 25, 26, 27, 2
8), the circuit pattern of the reticle 30 is illuminated with uniform illuminance, the circuit pattern image is projected on the wafer 32 by the projection lens system 31, and the circuit pattern image is formed on the resist of the wafer 32. Is being transcribed. The effect of such projection exposure is as described above with reference to FIGS. 3 and 4, and the resist on the wafer 32 is stably applied with i-line.
A clear fine pattern of 0.4 μm can be recorded.

Although the filter 17 and the aperture member 18 are located before the integrator 19, the filter 17 and the aperture member 18 may be located immediately after the integrator 19. In addition, a diaphragm member 18 shown in FIG. 6B used in a third embodiment to be described later may be used instead of the system including the filter 17 and the diaphragm member 18. 6 (A) and 6 (B) are views showing a third embodiment of the present invention, and show another example of a projection exposure apparatus for manufacturing a semiconductor which projects a fine pattern image by the method of the present invention. .

In the figure, the same members as those shown in FIG. 5 or members having the same functions are given the same numbers as those given in FIG. Therefore, comparing the apparatus of FIG. 5 with the apparatus of the present embodiment, the difference between the apparatus of FIG. 5 and the apparatus of FIG. 5 is that, as shown in FIG.
Cross ND, the point where the opening of
Instead of the filters, four independent filters 17a, 17b, 17c, 1
7d, and a quadrangular pyramid prism 13 is inserted between the mirrors 12 and 14.

In this embodiment, the four-divided detector-4
The output from 2 is used for purposes other than the opening / closing control of the shutter 15, and the measurement unit (35-37) is also used.

Hereinafter, the operation and effect of this embodiment will be described with emphasis on differences from the above embodiment.

A quadrangular pyramid prism 13, a filter 17a,
When the integrator 19 is illuminated with the light from the mercury lamp 11 without the 17b, 17c, 17d and the stop member 18, the integrator 19 resembles a Gaussian distribution having a high peak at the center on the light exit surface of the integrator 19. This results in a secondary light source having a distributed light quantity. Since the light exit plane of the integrator 19 is conjugate with the pupil plane of the projection lens system 31, an effective light source having a peak of the light amount distribution at the pupil center is formed on this pupil plane. As described above, the effective light source used in the present invention has a light amount distribution that does not show a peak at the center of the pupil.
It is necessary to block light incident near the center of the integrator 19 as in the above embodiment. However, if the aperture member 18 is simply placed in front of the integrator 19, most of the light from the mercury lamp 11 is cut off, resulting in a large light loss. Therefore, in this embodiment, the quadrangular pyramid prism 13 is inserted immediately after the elliptical mirror 12 to control the illuminance distribution on the optical integrator 19.

The light emitting part of the mercury lamp 11 has an elliptical mirror-1.
2, the light emitted from the mercury lamp 11 and reflected by the elliptical mirror 12 is converted by the quadrangular pyramid prism 13 into four light beams deflected in different directions. . These four light beams are reflected by the mirror 14 and reach the position of the shutter 15. If the shutter 15 is open, the light enters the filter 16 as it is, and the projection lens system 31 that projects the image of the reticle 30 onto the resist (photosensitive layer) on the wafer 32 by the filter 16 has the best performance. Is selected from the emission spectrum of the mercury lamp 11 so that

After passing through the field lens 105, the four light beams from the filter 16 are passed through the field lens 105, respectively, and then the filters 17a, 17b, 17c,
17d. These four filters make the light amounts of the four light beams substantially equal to each other, whereby the light exit surface of the integrator 19 and the projection lens system 31 are formed.
Is a correction member for correcting the symmetry of the amount of light between the four portions of the effective light source formed on the pupil plane of FIG. When adjusting the light attenuation function of each filter, several types of N
A D filter may be prepared and adjusted by switching the ND filter. Alternatively, each filter may be constituted by an interference filter, and the interference filter may be tilted by utilizing the narrow band characteristic of the interference filter. It may be adjusted depending on the situation.

The diaphragm member 18 includes filters 17a and 17
b, 17c, and 17d. The diaphragm member 18 has four circular openings as shown in FIG. 6 (B), and each of the four circular openings is provided with a filter.
The four light beams from 17a, 17b, 17c, and 17d correspond one-to-one. Then, the integrator 19 is illuminated with light from the four apertures of the aperture member 18, and the light exit surface of the integrator 19 and the pupil surface of the projection lens system 31 correspond to the aperture of the aperture member 18. The effective light source shown in FIG. 3A is formed.

Normally, the aperture shape of the aperture member 18 is set to a shape corresponding to the outer shape of each minute lens constituting the integrator 19. Therefore, when the cross section of each microlens is hexagonal, the aperture shape is also formed along the hexagon of the microlens.

The light from the integrator 19 is directed to the blade 24 via the lens 20, the mirror 21, the lens 22, and the half mirror 23. At this time, as described above, the light beams from each lens of the integrator 19 overlap each other on the blade 24, and the blade 24 is illuminated with uniform illuminance. Half mirror 23 is an Integra
A part of the light beam from each lens of the lens 19 is reflected, and the light shielding plate 40 is illuminated by the reflected light. The light from the opening of the light shielding plate 40 is divided into four parts by a lens 41.
The light is focused on 42.

The light passing through the opening of the blade 24 is directed to the reticle 30 by the mirror 25, the lens 26, the mirror 27 and the lens 28. Since the opening of the blade 24 and the circuit pattern of the reticle 30 are conjugate to each other, the light beams from the lenses of the integrator 19 also overlap on the reticle 30, illuminating the reticle 30 with uniform illuminance. I do. Then, an image of the circuit pattern of the reticle 30 is projected by the projection lens system 31.

Each detector of the quadrant detector 42
Correspond to each of the four parts of the effective light source which are separated from each other as shown in FIG. 3 (A), and the light amount of each part can be detected independently. As described above, the shutter 15 can be opened and closed by adding the outputs of the respective detectors. On the other hand, by comparing the outputs of the detectors with each other, it is checked whether or not the proportions of the light amounts of the individual portions of the effective light source are unbalanced. At this time, performing the calibration between the detectors of the four-divided detector 42 leads to increasing the reliability at the time of checking. This calibration will be described later.

The shape of the effective light source formed on the pupil plane of the device corresponds to the shape of the integrator 19. Since the integrator 19 itself is a collection of minute lenses, the light amount distribution of the effective light source is discrete when viewed in detail, corresponding to the shape of each minute lens. For example, the light amount distribution shown in FIG. 3A is realized.

In this embodiment, the light amount monitors (23, 40 to
42) and the measurement unit (35 to 37) is used to check the light amount distribution of the effective light source. For this purpose, the XY stage 34 is moved to bring the measurement units (35 to 37) directly below the projection lens system 31. In this measurement unit, the light that exits the illumination system and reaches the image plane of the projection lens system 31 is guided to the photoelectric converter 37 through the opening 35a of the glass plate 35 and the opening of the case 36. The light receiving surface of the opening 35a is set at the image plane position of the projection lens system 31. Glass plate 3
5 is attached to a case 36, and the case 36 has an opening at the center as described above. Here, the opening of the case 36 is shifted from the opening of the glass plate 35 by a predetermined amount. , Measuring unit. When illumination is performed by the illumination system of the present embodiment, four portions of the effective light source shown in FIG. The shape and size of the opening of the case 36 can be changed in the same manner as the opening of the blade 24. By changing the size of the opening using a drive system (not shown), the four portions of the effective light source can be individually formed. To detect
Four parts of the effective light source can be detected at once.
On the other hand, the photoelectric converter 37 has a light receiving portion having an area capable of receiving all light beams passing through the opening 35a of the glass plate 35. If the response area of the electric system deteriorates due to the area of the light receiving section of the photoelectric converter 37 becoming too large, the glass plate 3
A condensing lens is inserted between the photoelectric conversion device 5 and the photoelectric converter 37, and the light beam from the opening 35a of the glass plate 35 is condensed by the lens to reduce the area of the light receiving portion of the photoelectric converter 37 to improve the response characteristics. be able to. In addition, by moving the XY stage 34 along the image plane while the opening of the case 36 is set so that the four portions of the effective light source can be detected at one time, the uniformity of the image plane illuminance is improved. You can also measure.

The result of measuring the light amount (intensity) of each part of the effective light source by moving the opening of the case 36 is shown in FIG.
A comparison with the output of the corresponding detector of the split detector 42 is made. That is, since the photoelectric converter 37 on the XY stage 34 side is used as a reference detector and the output of the four-divided detector 42 can be calibrated, the change over time of the effective light source can be monitored in a stable state. I can go. Then, the imbalance of the light amounts between the respective portions of the effective light source is detected by the four-division detector 42 or the photoelectric converter 37, and based on the result, the filters 17a, 17b, 17c, and 17d determine the respective portions of the effective light source. The adjustment is performed so that the light amount is matched.

In this embodiment, the diaphragm member 1 shown in FIG.
Due to the operation of 8, the light amount distribution on the xy axis and the pupil center (optical axis) corresponding to the vertical and horizontal patterns of the reticle 30 shown in FIG. Bee
The illumination system (11, 1) is formed while forming an effective light source having no
2, 13, 14, 15, 16, 17, 18, 19, 2,
0, 21, 22, 23, 24, 25, 26, 27, 2
8), the circuit pattern of the reticle 30 is illuminated with uniform illuminance, the circuit pattern image is projected on the wafer 32 by the projection lens system 31, and the circuit pattern image is formed on the resist of the wafer 32. Is being transcribed. The effect of such projection exposure is as described above with reference to FIGS. 3 and 4, and the resist on the wafer 32 is stably applied with i-line.
A sharp fine pattern of 0.4 μm can be recorded with a large depth of focus.

FIG. 7 is a view showing a fourth embodiment of the present invention, and is a partial schematic view showing an improved example of the projection exposure apparatus for manufacturing a semiconductor shown in FIG. Accordingly, in FIG. 7, the same members as those in the embodiment of FIG. 6 are given the same numbers as those in FIG.

In the figure, 11 is an extra-high pressure mercury lamp, and 12 is an elliptical mirror. Here, the light emitted from the elliptical mirror 12 is beamed.
It is divided by a group of splitters (51, 53). Third
In order to form an effective light source having four parts shown in FIG. 3A, the light emitted from the elliptical mirror 12 is sequentially divided by a first beam splitter 51 and a second beam splitter 53. I have. 52 is a bending mirror for the optical path. The second beam splitter 53 is disposed obliquely over both optical paths of the two light beams split by the first beam splitter 51, and each of the two light beams travels along the paper surface. The light is split and a part of each light beam is bent in a direction perpendicular to the plane of the drawing. The other part of each light beam travels along the paper as shown. Also, the second
A mirror optical system is provided in the optical path of the part of the light beam from the beam splitter 53 to reflect the part of the light beam and direct it to another light path parallel to the optical path of the other part. Thus, the optical paths divided into four by the beam splitter group (51, 53) and the mirror 52 and the mirror optical system (not shown) are as follows.
The light exit surface of the integrator 19 is coupled to form a secondary light source having a light distribution as shown in FIG. Thus, an effective light source shown in FIG. 3A is formed on the pupil plane of the projection lens system 31.

In the two divided optical paths in the paper,
The relay lenses 61a and 61b are placed, respectively, and the light traveling in each optical path is converged on the integrator 19 by the action of the relay lenses 61a and 61b. As a result of the insertion of the first beam splitter, since the optical path lengths of the two optical paths are different from each other, the configurations and the focal lengths of the relay lenses 61a and 61b are slightly different from each other. The same applies to a pair of relay lenses (not shown) placed in a pair of optical paths not in the plane of the drawing.

Reference numeral 63 denotes a beam splitter group (51, 5).
Shutters that can control opening and closing of each of the four light beams obtained in 3), 16a and 16b are wavelength selection filters placed on two divided light paths in the drawing, and the other two light paths outside the drawing. Are also provided with similar filters. These filters are the filter-1 of the above embodiment.
As in 6, i-line is extracted from the light from the mercury lamp 11. 1
Reference numerals 7a and 17b denote filters for adjusting the amounts of light of the respective portions of the effective light source, which are placed in two divided optical paths in the plane of the paper. The same applies to each of the other two optical paths outside the plane of the paper. A filter is placed. And these filters-
Functions of the filters 17a, 17b, 17
It has the same functions as c and 17d.

In this embodiment, since the optical path leading to the integrator is spatially divided into four, the integrator is divided into four.
It consisted of a set of small integrators. Because of the degree of overlap of the optical paths, here the integrator-1
Only 9a and 19b are shown. Since the configuration after the integrator is the same as that of the above-described embodiment, further description is omitted.

FIG. 8 is a view showing a fifth embodiment of the present invention, and is a partial view showing still another example of a projection exposure apparatus for manufacturing a semiconductor for projecting a fine pattern image by the method of the present invention. It is a schematic diagram.

The apparatus of this embodiment projects a circuit pattern image while moving the position of the effective light source over time to form an effective light source as shown in FIG. 3A on the pupil plane. Expose. In FIG. 8, the same members as those in the above embodiments are given the same numbers as those in the above embodiments. Therefore, in the figure, reference numeral 11 denotes an ultra-high pressure mercury lamp, 12 an elliptical mirror, 14
Denotes a bending mirror, 15 denotes a shutter, 16 denotes an interference filter for wavelength selection, 19 denotes an optical integrator, and a system (not shown) after a projection lens system 31 is the same as that of each of the above embodiments. is there.

The characteristic structure of this embodiment is the
That is, a parallel flat plate 71 that moves with time is placed behind the tar 19. The parallel flat plate 71 is disposed obliquely with respect to the optical axis of the illumination optical system, and plays a role of shifting the optical axis by swinging so as to change the inclination angle with respect to the optical axis as shown in the figure. Therefore, when the integrator 19 is observed from the reticle 30 side through the parallel plate 71, it appears that the integrator 19 moves up and down or left and right with the swing of the parallel plate 71. Here, since the parallel flat plate 71 supports the parallel flat plate so as to be capable of rotating around the optical axis, the parallel flat plate 71 is rotated at a predetermined angle with respect to the optical axis to thereby rotate the projection lens system. In the 31 pupil planes, a single effective light source can be arranged at any position on the circumference of a certain radius away from the optical axis (pupil center). At the time of actual exposure, when the single effective light source comes to a predetermined position by moving the parallel flat plate 71, the attitude of the parallel flat plate 71 is fixed, and exposure is performed for a predetermined time. This operation is performed four times so that a single effective light source is formed in each of the four portions of the effective light source shown in FIG. 3A, thereby completing the exposure of one shot.

In this embodiment, the mercury lamp 11 is used as the light source. However, when the light source emits a pulse light like an excimer laser, the movement of the parallel flat plate 71 is set as a continuous movement. Exposure control may be performed such that the light source emits light when the parallel plate 71 reaches a predetermined position. At this time, an excimer laser is used as a light source, and the period of rotation of the parallel plate 71 around the optical axis is adjusted by the excimer laser.
It is convenient to match with the light emission repetition period. For example, assuming that the laser emits light at 200 Hz, efficient exposure can be performed by controlling the rotation speed of the parallel plate 71 so that the effective light source moves to the next quadrant each time light emission is performed. Can be.

In the case where a method in which a single effective light source moves in time as described above is employed, the effective light source portions formed in several parts on the pupil are made of light energy from the same light source.
It is easy to always set the intensities of the effective light source sections separated on the pupil plane to be always the same. It is for this reason that the filter 17 for correcting the effective light source light amount as in the above embodiments is not provided in this embodiment.

The light passing through the parallel flat plate 71 uniformly illuminates the reticle 30 via the lens 72, the half mirror 73, and the lens 74. In this embodiment, a blade 78 different from the blade 24 of each embodiment is arranged near the reticle 30 because there is no first imaging optical system set in each embodiment. The blade 78 has the same configuration and function as the blade 24, and the size of the opening is variable according to the size of the circuit pattern formed on the reticle 30.

The mirror 73 reflects most of the incident light while transmitting a part of the incident light to guide the light to a light amount monitor for controlling the exposure amount. 75 is a condenser lens, and 76 is a pinhole plate at a position optically equivalent to the reticle 30. Light from the mirror 73 is condensed on the pinhole plate 76 by the lens 75 and passes through the pinhole of the pinhole plate 76. The light thus detected is received by the photodetector 77, and a signal corresponding to the intensity of the incident light is output from the photodetector 77. A computer (not shown) of the apparatus controls opening and closing of the shutter 15 based on this signal. In this embodiment, since it is not necessary to monitor the light amount ratio of each portion between the effective light sources, the photodetector 77 does not need to be a four-divided detector.

In this embodiment, the reticle 3 is formed while forming an effective light source shown in FIG.
The circuit pattern of No. 0 is illuminated with uniform illuminance, the circuit pattern image is projected on the wafer by the projection lens system 31, and the circuit pattern image is transferred to the resist on the wafer. The effect of such projection exposure is as described above, and a stable and clear 0.4 μm
m fine patterns can be recorded.

FIG. 9 is a view showing a sixth embodiment of the present invention, and is a partial view showing still another example of a projection exposure apparatus for manufacturing a semiconductor for projecting a fine pattern image by the method of the present invention. It is a schematic diagram.

In this embodiment, a KrF excimer laser 81 (center wavelength: 248.4 nm, bandwidth: 0.0) was used as a light source.
3 to 0.005 nm). The excimer laser 81 emits pulses, so that exposure control is performed by driving the laser itself without providing a shutter, and that the laser itself has a filter and emits laser light. Since the bandwidth is narrowed, the feature is that no interference filter for wavelength selection is provided. Beam splitter group (51, 53), mirror-5
2. The functions of the filter 17 and the integrator 19 are as follows.
This is the same as the embodiment shown in FIG. Also, Integra
6A is the same as that shown in FIG. 6A, except that the projection lens system (not shown) comprises a lens assembly designed for a wavelength of 248.4 nm and containing only synthetic quartz as a main component. I have.

In the case of the excimer laser 81, since the coherency of the laser light is high, it is necessary to suppress the generation of the speckle pattern. For this reason, in this embodiment, the incoherent unit 82 is placed after the light is split by the beam splitter groups 51 to 53. Various methods have been disclosed in the past for the method of removing speckles in an illumination optical system using an excimer laser. However, the production of an effective light source according to the present invention is not essentially contradictory thereto, and various known methods are known. Various methods can be applied. Therefore, the details of the unit 82 will not be described here.

In this embodiment, the illustrated optical system (17, 1
9, 51, 52, 53, and 82), while illuminating the circuit pattern of the reticle with uniform illuminance while forming an effective light source shown in FIG. Then, the circuit pattern image is projected onto the wafer by the projection lens system, and the circuit pattern image is transferred to the resist on the wafer. The effect of such projection exposure is as described above, and a clear and fine pattern of 0.3 to 0.4 μm can be stably recorded on the resist on the wafer.

FIG. 10 is a view showing a seventh embodiment of the present invention, and is a partial schematic view showing an apparatus improved from the sixth embodiment shown in FIG.

In this embodiment, the laser from the laser 81 is used.
The light is separated into four light beams by a reflection type quadrangular pyramid prism. In the apparatus shown in FIG. 6, a light beam is separated by using a transmission type four-sided pyramid prism 13, but the same can be performed by a reflection type. Of course, the configuration of the present invention can be realized by using an ultra-high pressure mercury lamp as a light source, but here, an example using a KrF excimer laser as a light source is shown. The laser light emitted from the laser 81 is enlarged and converted to an appropriate beam size by the afocal converter 91, and then enters the quadrangular pyramid prism 92. The arrangement of the four-sided pyramid prism is set so that the four reflecting surfaces are oriented in a direction in which an effective light source as shown in FIG. 3B can be formed at the pupil position of the projection lens system (not shown). Numeral 93 denotes a mirror for bending the light divided / reflected on each reflecting surface of the quadrangular pyramid prism 92.
The subsequent configuration is the same as that of the device shown in FIG.
The system after 19 is the same as that of FIG. 6 (A). However, the projection lens system (not shown) is composed of a lens assembly mainly composed of synthetic quartz, which is designed for a wavelength of 248.4 nm.

Also in this embodiment, the illustrated optical system (17, 1
9, 91, 92, 93, 82), while forming an effective light source shown in FIG. 3A on the pupil plane of the projection lens system (not shown), illuminates the circuit pattern of the reticle with uniform illuminance. Then, the circuit pattern image is projected onto the wafer by the projection lens system, and the circuit pattern image is transferred to the resist on the wafer. The effect of such projection exposure is as described above, and a clear and fine pattern of 0.3 to 0.4 μm can be stably recorded on the resist on the wafer.

FIG. 11 is a view showing an eighth embodiment of the present invention, and is a partial view showing still another example of a projection exposure apparatus for manufacturing a semiconductor for projecting a fine pattern image by the method of the present invention. It is a schematic diagram.

In this embodiment, an illumination system using the fiber bundle 101 is shown. The light incident surface of the fiber bundle 101 is arranged at a position where the light of the ultra-high pressure mercury lamp 11 is condensed by the elliptical mirror 12, the light beam is led through each fiber, and the light incident surface of the integrator 19. Is led to. The end of the fiber bundle 101 on the side opposite to the ultrahigh pressure mercury lamp 11, that is, the light emitting surface, is branched into four bundles, each of which corresponds to each part of the effective light source in FIG. 3 (A). At the outlet of each fiber bundle, a filter 17 for adjusting the light amount of each part of the effective light source is arranged. The optical system after this is the eighth
The configuration of the embodiment shown in FIG. However, in order to measure the balance of the light amount (four portions of the secondary light source and the four portions of the effective light source) of the light from each fiber bundle, the four-divided detector 102 is used for the photodetector of the light amount monitor. Is used. 4-split detector-10
Each of the two detectors has four integrators
It corresponds to the exit of Tar-19.

In this embodiment, the reticle 3 is formed while forming an effective light source shown in FIG.
The circuit pattern of No. 0 is illuminated with uniform illuminance, the circuit pattern image is projected on the wafer by the projection lens system 31, and the circuit pattern image is transferred to the resist on the wafer. The effect of such projection exposure is as described above, and a stable and clear 0.4 μm
m fine patterns can be recorded.

FIG. 12 is a view showing a ninth embodiment of the present invention, and is a partial view showing still another example of a projection exposure apparatus for manufacturing a semiconductor for projecting a fine pattern image by the method of the present invention. It is a schematic diagram.

In this embodiment, an illumination system is constituted by using a plurality of light sources. Here, an ultra-high pressure mercury lamp 11 is used as a light source.
Although a and 11b are used, it is also possible to use an excimer laser as a light source and build a laser optical system, that is, an optical system for a beam that is parallel and has a small divergence angle.

In this embodiment, although not shown because of overlap, four ultra-high pressure mercury lamps are placed, and light beams from each of the four ultra-high pressure mercury lamps enter the concave lens 103 and are integrated by the concave lens 103. Then, the light reaches an integrator 19 via a wavelength selection interference filter 16 and four filters 17 for adjusting the light amount of each portion of the effective light source. The configuration of the optical system after the integrator 19 is 11th.
The effective light source shown in FIG. 3A is formed on the pupil plane of the projection lens system 31 in the same manner as in the apparatus shown in FIG. Therefore, also in this embodiment, the circuit pattern image is projected on the wafer by the projection lens system 31.
The circuit pattern image is transferred to the resist on the wafer by projecting the image onto the resist. The effect of such projection exposure is as described above.
A clear 0.4 μm fine pattern can be recorded.

In the projection exposure apparatus for semiconductor manufacturing described above, the arrangement of the effective light source on the pupil plane is fixed. However, as described in the first part of the embodiment, the parameter p indicating the center position of each part of the effective light source and the parameter q indicating its radius or the radius of a circle circumscribing the parameter p, The optimum value of the shape of each portion of the light source differs depending on the type of circuit pattern to be subjected to projection exposure. So, for example,
Parameters representing the shape of the effective light source in the apparatus of each embodiment
It is advisable to construct a system that makes p and q variable. For example, the one using the inner drawing member 18 of each embodiment is different from the one using the drawing member 18.
It is assumed that an aperture having a variable aperture shape is used, or a plurality of diaphragms having different aperture shapes are prepared.

Although the apparatus described above is an apparatus for manufacturing a semiconductor, the present invention is not limited to the case of projecting an integrated circuit pattern image. That is, the present invention is applied to various cases in which an image of an article having a fine pattern mainly composed of vertical and horizontal patterns is projected by an optical system.

Although the apparatus described above uses a lens system as an optical system for image projection, the present invention is also applicable to a case where a mirror system is used.

Although the apparatus described above uses i-line laser light having a wavelength of 248.4 nm as light used for image projection, the present invention is applicable regardless of the type of wavelength. . Therefore, the present invention can be applied to, for example, a projection exposure apparatus for semiconductor manufacturing using g-line (436 nm) as an exposure wavelength.

[0092]

As described above, according to the present invention, by forming a predetermined effective light source on the pupil of the image projection optical system, an image of a minute pattern having a very high spatial frequency can be formed by a simple method.
Thus, there is an effect that projection can be performed.

[Brief description of the drawings]

[1] Description view showing a projection principle of micropattern image
You.

FIG. 2 is a diagram showing a light distribution on a pupil , (A) is a diagram showing a light distribution on a pupil when a conventional mask is used, and (B) is a diagram on a pupil when a phase shift mask is used. Figure der showing a light distribution in the
You.

In view of a first embodiment of the present invention; FIG, (A) is an explanatory view showing an example of the effective light source on the pupil of the first embodiment of the present invention, (B) the first of the present invention It is explanatory drawing which shows another example of the effective light source on the pupil of an Example .

FIG. 4 is a diagram showing frequency characteristics of a projection system forming the effective light source of FIG. 3A and a conventional projection system .

[5] a diagram showing a second embodiment of the present invention, (A) a schematic view of a projection exposure apparatus according to the second embodiment of the present invention, (B) a stop used in the second embodiment of the present invention Front view of member , (C)
FIG. 8 is an explanatory diagram of a cross filter used in a second embodiment of the present invention .

A diagram showing a third embodiment of the invention; FIG, (A) a schematic view of a projection exposure apparatus according to the third embodiment of the present invention, (B) a stop used in the third embodiment of the present invention It is a front view of a member .

FIG. 7 is a partial schematic view of a projection exposure apparatus showing a fourth embodiment of the present invention .

FIG. 8 is a partial schematic view of a projection exposure apparatus showing a fifth embodiment of the present invention .

FIG. 9 is a partial schematic view of a projection exposure apparatus showing a sixth embodiment of the present invention .

FIG. 10 is a partial schematic view of a projection exposure apparatus showing a seventh embodiment of the present invention .

FIG. 11 is a partial schematic view of a projection exposure apparatus showing an eighth embodiment of the present invention .

FIG. 12 is a partial schematic view of a projection exposure apparatus showing a ninth embodiment of the present invention .

[Explanation of symbols]

 Reference Signs List 1 pupil of projection optical system 2a effective light source 2b effective light source 2c effective light source 2d effective light source x axis along direction in which horizontal pattern extends y axis along direction in which vertical pattern extends

Continuation of the front page (56) References JP-A-3-27516 (JP, A) JP-A-61-91662 (JP, A) JP-A-61-44150 (JP, A) JP-A-1-257327 (JP) JP-A-59-160134 (JP, A) JP-A-60-230629 (JP, A) JP-A-61-169815 (JP, A) DIGEST OF PAPERS 1991 4TH MICRO PROCESS SS CONFERENCE, PP. 70-71 SPIE VOL. 1674 OPTIC AL / LASER MICROLITH OGRAPHY V (1992) PP. 741-752

Claims (22)

(57) [Claims] 1. A fine pattern having a vertical pattern and a horizontal pattern.
In the method of projecting the image of the pattern by the projection optical system
The center of the pupil of the projection optical system and the center of the pupil.
Other than a pair of shafts extending in the vertical and horizontal directions
In front of an effective light source with a large intensity distribution
Forming a pattern illumination stage on the pupil, wherein said pair of axes
Are the x and y axes of the xy coordinates, and the center of the pupil is the xy coordinates
When the origin and the radius of the pupil are 1, the effective light source is
The coordinates of each center position are (p, p), (-p, p),
It has four parts, (-p, -p) and (p, -p).
And an image projection method characterized by satisfying a condition of 0.25 <p <0.6 . 2. The center position corresponds to the light intensity distribution of each part.
2. The image projection method according to claim 1, wherein the position of the center of gravity is a center of gravity . 3. The effective light when the radius of the pupil is set to 1.
The shape of each of the four parts of the source is a circle of radius q,
Wherein 0.15 <q <0.3 is satisfied.
1. An image projection method. 4. The effective light when a radius of the pupil is set to 1.
The shape of each of the four parts of the source is a circumscribed circle of radius q
Non-circular and, 0.15 <image projection method of claim 1, characterized in that satisfy q <0.3 kick. 5. A central portion of a pupil of the projection optical system and the pupil.
A pair of shaft portions extending in the vertical and horizontal directions through the center of
2. The image projection method according to claim 1 , wherein the light intensity of the image is zero . 6. The image projection method according to claim 1, wherein said fine pattern is a circuit pattern . 7. The semiconductor device according to claim 1, wherein the fine pattern is a semiconductor integrated circuit.
2. The image projection method according to claim 1, wherein the method is a turn. 8. Light for illuminating said fine pattern is i-line, g
2. The image projection method according to claim 1, wherein the light is a line or light from an excimer laser . 9. A circuit pattern projected onto a substrate by a projection optical system.
A method of manufacturing a circuit having a step of transferring by shading.
Passing through the center of the pupil of the projection optical system and the center of the pupil
Extending in the direction of each of the vertical and horizontal circuit patterns
Intensity distribution where the light intensity of the other part is larger than that of the pair axis
Forming an effective light source on the pupil comprising:
Wherein the pair of axes are an x-axis and an y-axis of xy coordinates, and the pupil is
Is the origin of the xy coordinates, and the radius of the pupil is 1.
When the effective light source has coordinates (p,
p), (-p, p), (-p, -p), (p, -p)
It has certain four parts and the condition of 0.25 <p <0.6
A circuit manufacturing method characterized by satisfying the following . 10. The center position corresponds to the light intensity of each part.
9. The position of the center of gravity of the cloth.
Circuit manufacturing method. 11. When the radius of the pupil is 1, the effective value is
The shape of each of the four parts of the light source is a circle of radius q,
Wherein 0.15 <q <0.3 is satisfied.
8. The circuit manufacturing method according to 8. 12. When the radius of the pupil is 1, the effective
The shape of each of the four parts of the light source is a circumscribed circle of radius q
Non-circular and, 0.15 <image projection method of claim 9, wherein the this <br /> satisfying q <0.3 draw. 13. A central part and a front part of a pupil of the projection optical system.
A pair of axes extending in the vertical and horizontal directions through the center of the pupil
The light intensity of the portion is zero.
Circuit manufacturing method. 14. The light illuminating the circuit pattern is i
G-line or light from an excimer laser.
10. The circuit manufacturing method according to claim 9, wherein: 15. A projection light for projecting a reticle pattern.
The academic system and the pattern are set so as to have a predetermined relationship with the pattern.
The center part of the pupil of the shadow optics and each other passing through the center of the pupil
The light intensity of the other part is higher than that of the pair of orthogonal axes
Reticle forming an effective light source having a strong intensity distribution on the pupil
An illumination optical system, wherein the pair of axes is an x-axis of xy coordinates.
And the y axis, the center of the pupil is the origin of the xy coordinates,
When the radius is set to 1, the effective light source is positioned at each center position.
Coordinates are (p, p), (-p, p), (-p, -p),
(P, -p) with 0.25 <p <
0.6, which satisfies the condition of 0.6.
Place. 16. The center position corresponds to the light intensity of each part.
16. The position of the center of gravity of the cloth.
Projection exposure equipment. 17. When the radius of the pupil is 1, the effective value is
The shape of each of the four parts of the light source is a circle of radius q,
Wherein 0.15 <q <0.3 is satisfied.
15 projection exposure apparatuses. 18. The light illuminating the circuit pattern is i
G-line or light from an excimer laser.
16. The projection exposure apparatus according to claim 15, wherein: 19. The illumination optical system changes the value of p.
18. The method according to claim 15, further comprising changing means.
Projection exposure equipment. 20. The illumination optical system according to claim 1, wherein each of the p and q
2. The method according to claim 1, further comprising changing means for changing the value.
7. Projection exposure apparatus. 21. An aperture having a variable aperture shape.
21. The projection dew according to claim 19 or 20, wherein
Light device. 22. A plurality of changing means having different opening shapes.
21. The diaphragm according to claim 19, wherein
Projection exposure equipment.