JP2004266125A - Projection aligner, projection exposure method, and device manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the throughput of a work for exposing a circuit pattern while forming an unexposed part in the vicinity of the outer circumference of a circular substrate. <P>SOLUTION: A circular masking blade 3 comprises a plate having a circular opening, and shuts off a light emitted to the vicinity of the outer circumference of a substrate 1 to form an unexposed part in the vicinity of the outer circumference of the substrate 1. When one shot is finished and the substrate 1 is stepwise moved, a controller 51 drives an XY moving mechanism 31 so as to move XY positions of the circular masking blade 3 in a way of keeping a relative position between the substrate 1 and the opening of the circular masking blade 3 constant. After the substrate 1 and the circular masking blade 3 are moved, a succeeding shot is carried out and repeating the operations above exposes the entire substrate 1. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a projection exposure apparatus and a projection exposure method used for forming a circuit pattern in a device manufacturing process, and a device manufacturing method using the same.
[0002]
[Prior art]
In a process of manufacturing a semiconductor device such as an IC or an LSI or a display device such as a liquid crystal panel, a circuit pattern is formed by using a so-called photolithography technique. In the photolithography technology, a pattern formed on a reticle or a photomask (hereinafter, these are collectively referred to as a “mask”) is projected on a substrate such as a semiconductor wafer coated with a photosensitive material (resist) using a projection exposure apparatus. Transfer to the top. Then, a resist pattern is formed by a development process, and a circuit pattern is formed by dry etching using the resist pattern as a mask.
[0003]
FIG. 12 is a diagram showing a schematic configuration of a conventional step type projection exposure apparatus. The step-type projection exposure apparatus repeats step movement of a substrate and exposure in a stationary state (step-and-repeat), and repeatedly exposes a pattern of a mask on the substrate, and is generally called a stepper. In FIG. 12, an optical system, an alignment mechanism, and the like for aligning a circuit pattern already formed on the substrate with a mask pattern are omitted.
[0004]
The mask 2 is mounted on a mask stage (not shown) by a transport mechanism (not shown). The mask 2 mounted on the mask stage is accurately positioned by an alignment mechanism (not shown).
[0005]
A substrate 1 such as a semiconductor wafer is mounted on a substrate chuck 5 after being pre-aligned by a transfer mechanism (not shown). The substrate 1 mounted on the substrate chuck 5 is accurately aligned by an alignment mechanism (not shown).
[0006]
When the shutter 13 is opened for a certain period of time, the light generated by the mercury lamp 10a is collected by the elliptical mirror 11, reflected by the mirror 12, and enters the fly-eye lens 14. The light uniformized by the fly-eye lens 14 passes through the illumination σ stop 15 and is emitted from the illumination condenser lens 16 to the masking blade 4. The light that has passed through the masking blade 4 is reflected by a mirror 17 and is emitted from the illumination imaging lens 18 to the mask 2.
[0007]
Here, the masking blade surface and the mask surface are in a conjugate positional relationship via the illumination imaging lens 18, and only the region of the light that has passed through the masking blade 4 is accurately irradiated on the mask surface. The light transmitted through the mask 2 is irradiated onto the substrate 1 from the projection lens 19, whereby the pattern of the mask 2 is projected and exposed on the substrate 1.
[0008]
The shutter 13 is for controlling the amount of light emitted to the substrate 1, and the opening and closing time is controlled so that the exposure amount is constant. The illumination σ stop 15 is a stop for optimally setting the contrast of the image of the pattern of the mask 2 projected on the substrate 1, and is usually set to a partial coherency σ of about 0.6.
[0009]
The masking blade 4 is a stop for determining a projection exposure area, and is usually composed of four movable plates, and can freely set a rectangular opening. Generally, the projection exposure area of the step-type projection exposure apparatus is relatively small as compared with the area of the substrate 1, and the entire substrate 1 cannot be exposed by one exposure. Therefore, when the exposure of one projection exposure area is completed, the XYZθ stage 6 provided below the substrate chuck 5 is driven to move the XY position of the substrate 1 step by step, and then the exposure is performed again. By repeating these operations, the entire substrate 1 is exposed.
[0010]
The step-type projection exposure apparatus is an expensive apparatus, and in order to increase the processing capacity, it is necessary to increase the number of chips of a device created by one exposure (shot) and reduce the number of shots. For this reason, the shot size is generally relatively large compared to the chip size of the device.
[0011]
Japanese Patent Application Laid-Open No. 2001-297962 (Patent Document 1) discloses such a step-type projection exposure apparatus.
[Patent Document 1]
JP 2001-297962 A
[0012]
[Problems to be solved by the invention]
In order to manufacture as many devices as possible from a single substrate, device chips must be formed over as large a region of the substrate surface as possible. However, when a fine pattern is transferred to the vicinity of the outer periphery of the substrate, the flatness of the surface is not sufficient in the vicinity of the outer periphery of the substrate due to the effects of chamfering and the like, so the pattern formation becomes incomplete and the pattern peels off. Is more likely to occur. The peeled pattern becomes a foreign substance, which causes a reduction in the yield of the device.
[0013]
As a countermeasure, in the case of a positive resist, a process of exposing the vicinity of the outer periphery of the substrate in a ring shape to remove a pattern formed near the outer periphery is performed. However, this method is not always effective for a metal-based film (deposition film) that is easily peeled. In the case of a metal-based film that is easily peeled, it is better to perform etching after leaving an unexposed resist as a protective film in the vicinity of the outer periphery of the substrate, so that pattern peeling is reduced and the yield is improved.
[0014]
For this reason, conventionally, the shape of the opening of the masking blade is changed for each shot that exposes the vicinity of the outer periphery of the substrate to form an unexposed portion near the outer periphery of the substrate. For this reason, there is a problem that it takes time to move the movable plate of the masking blade, and the throughput is reduced.
[0015]
As the number of obtained chips per board increases, the arrangement of chips on the board becomes more complicated. Further, in the step-type projection exposure apparatus, as the shot size is increased and the number of chips per shot is increased in order to increase the processing capacity, the arrangement of the chips on the substrate becomes more complicated. And, as the arrangement of the chips on the substrate becomes more complicated, the shape of the opening of the masking blade must be changed many times in order to form an unexposed portion near the outer periphery of the substrate, and the decrease in throughput is remarkable. Become.
[0016]
A negative photosensitive material such as photosensitive polyimide may cause a more serious problem. Photosensitive polyimide is often used as a protective film for a semiconductor, but is very poor in compatibility with a dicing blade when cutting a substrate because it is an organic material and has elasticity. For this reason, if the photosensitive polyimide remains on the chamfered portion near the outer periphery of the substrate due to insufficient resolution of the scribe line pattern, cutting cannot be performed well. Moreover, in the case of the negative type, it is not possible to expose and remove the vicinity of the outer periphery of the substrate in a ring shape as in the case of the positive type. Therefore, it is essential to change the shape of the opening of the masking blade to form an unexposed portion near the outer periphery of the substrate. Since the photosensitive polyimide has low sensitivity and requires a larger amount of exposure, the throughput is significantly reduced.
[0017]
SUMMARY OF THE INVENTION It is an object of the present invention to improve the throughput of an operation of exposing a circuit pattern while forming an unexposed portion near the outer periphery of a circular substrate.
[0018]
Another object of the present invention is to reduce device manufacturing costs.
[0019]
[Means for Solving the Problems]
The projection exposure apparatus of the present invention is a projection exposure apparatus that includes a projection optical system and projects a pattern of a mask onto a circular substrate, has a circular opening or a part thereof, and is irradiated near the outer periphery of the substrate. And a light blocking means for blocking light.
[0020]
Further, the projection exposure method of the present invention is a projection exposure method for projecting a mask pattern onto a circular substrate using a projection optical system, using a light shielding means having a circular opening or a part thereof, The light irradiated to the vicinity of the outer periphery of the substrate is blocked to form an unexposed portion near the outer periphery of the substrate.
[0021]
The diameter of the opening of the blocking means is a fixed value according to the diameter of the substrate and the width of the unexposed portion, and does not depend on the shot size and the number of shots. Therefore, the same blocking means can be applied to any shot size and shot number. When an unexposed portion is formed in the vicinity of the outer periphery of the substrate, it is not necessary to change the shape of the opening by moving the movable plate of the masking blade as in the related art, and the throughput is improved.
[0022]
In step-type projection exposure, when the entire substrate is exposed with a plurality of shots and the substrate is moved to the position of each shot, or when the substrate is moved to the position of a shot that exposes the vicinity of the outer periphery of the substrate, the substrate and the light shielding means are exposed. The light shielding means is moved so that the relative position with respect to the opening is kept constant. For this purpose, the projection exposure apparatus includes first moving means for moving the substrate stepwise, and second moving means for moving the light shielding means so as to keep the relative position between the substrate and the opening of the light shielding means constant. When the second moving means moves the light shielding means in synchronization with the movement of the substrate by the first moving means, the moving time is shortened, and the throughput is further improved. Alternatively, when the second moving means moves the light shielding means when moving the substrate to the position of the shot for exposing the vicinity of the outer periphery of the substrate, the movement of the blocking means can be omitted for a shot which does not reach the vicinity of the outer periphery of the substrate, and the throughput is reduced Further improve.
[0023]
In the step-and-scan projection exposure, each shot is further performed by synchronously scanning the substrate and the mask in a one-dimensional direction or a two-dimensional direction relative to the projection optical system. To move the light shielding means. For this reason, the projection exposure apparatus further includes a scanning unit that synchronously scans the substrate and the mask in one-dimensional direction or a two-dimensional synchronous scan with respect to the projection optical system; And third moving means for moving the light shielding means in synchronization with the scanning. The third moving means may also serve as the second moving means.
[0024]
In the scanning projection exposure, exposure of the entire substrate is performed by synchronously scanning the substrate and the mask in a two-dimensional direction relative to the projection optical system, and the light shielding means is moved in synchronization with the scanning of the substrate. Therefore, the projection exposure apparatus includes a scanning unit that synchronously scans the substrate and the mask in a two-dimensional direction relative to the projection optical system, and a unit that moves the light shielding unit in synchronization with the scanning of the substrate by the scanning unit. Is provided.
[0025]
In step-and-scan projection exposure or scan projection exposure, a projection optical system including a concave mirror and a combination lens including a concave lens made of a single optical glass and an achromatic convex lens made up of three kinds of lenses made of different optical glasses When a 1: 1 erect image of the pattern of the mask is projected onto the substrate by using the above, projection exposure with high illuminance and high contrast can be performed. Further, the cost of the projection optical system is greatly reduced, and the cost of the apparatus is reduced.
[0026]
The device manufacturing method of the present invention includes a step of forming a circuit pattern using the above-described projection exposure method. According to the above-mentioned projection exposure method, the throughput of the operation of exposing the circuit pattern while forming the unexposed portion near the outer periphery of the substrate is improved, so that the manufacturing cost of the device is reduced.
[0027]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a diagram showing a schematic configuration of a projection exposure apparatus according to an embodiment of the present invention. This embodiment shows an example of a step type projection exposure apparatus. The projection exposure apparatus includes a mask 2, a circular masking blade 3, a substrate chuck 5, an XYZθ stage 6, a mercury lamp 10a, an elliptical mirror 11, mirrors 12, 17, a shutter 13, a fly-eye lens 14, an illumination σ diaphragm 15, an illumination condenser lens. 16, the illumination imaging lens 18, the projection lens 19, the XY moving mechanism 31, and the control device 51. In FIG. 1, an optical system, an alignment mechanism, and the like for aligning a circuit pattern already formed on a substrate with a mask pattern are omitted.
[0028]
The mask 2 is mounted on a mask stage (not shown) by a transport mechanism (not shown). The mask 2 mounted on the mask stage is accurately positioned by an alignment mechanism (not shown).
[0029]
A substrate 1 such as a semiconductor wafer is mounted on a substrate chuck 5 after being pre-aligned by a transfer mechanism (not shown). The substrate 1 mounted on the substrate chuck 5 is accurately aligned by an alignment mechanism (not shown).
[0030]
When the shutter 13 is opened for a certain period of time, the light generated by the mercury lamp 10a is collected by the elliptical mirror 11, reflected by the mirror 12, and enters the fly-eye lens 14. The light uniformized by the fly-eye lens 14 passes through the illumination σ stop 15 and is emitted from the illumination condenser lens 16 to the circular masking blade 3. The light that has passed through the circular masking blade 3 is reflected by a mirror 17 and is emitted from the illumination imaging lens 18 to the mask 2.
[0031]
Here, the circular masking blade surface and the mask surface are in a conjugate positional relationship via the illumination imaging lens 18, and only the region of light that has passed through the circular masking blade 3 is accurately irradiated on the mask surface. The light transmitted through the mask 2 is irradiated onto the substrate 1 from the projection lens 19, whereby the pattern of the mask 2 is projected and exposed on the substrate 1.
[0032]
The shutter 13 is for controlling the amount of light emitted to the substrate 1, and the opening and closing time is controlled so that the exposure amount is constant. The illumination σ stop 15 is a stop for optimally setting the contrast of the image of the pattern of the mask 2 projected on the substrate 1, and is usually set to a partial coherency σ of about 0.6.
[0033]
The circular masking blade 3 is a stop for forming an unexposed portion in the vicinity of the outer periphery of the substrate 1, and is constituted by a plate having a circular opening. The circular masking blade 3 is attached to the XY moving mechanism 31, and is movable in the XY directions.
[0034]
When one shot is completed, the control device 51 drives the XYZθ stage 6 to move the XY position of the substrate 1 stepwise. Further, the control device 51 drives the XY moving mechanism 31 to move the XY position of the circular masking blade 3 so that the relative position between the substrate 1 and the opening of the circular masking blade 3 is kept constant. The movement of the circular masking blade 3 may be performed after the movement of the substrate 1, or may be performed in synchronization with the movement of the substrate 1. When the circular masking blade 3 is moved in synchronization with the movement of the substrate 1, the movement time is shortened, and the throughput can be further improved. After the movement of the substrate 1 and the circular masking blade 3, the next shot is performed, and by repeating these operations, the entire substrate 1 is exposed.
[0035]
FIG. 2 is a side view showing the positional relationship between the substrate and the opening of the circular masking blade. FIG. 2 shows an example in which the imaging magnification of the projection optical system and the illumination optical system is the same magnification. FIG. 2A shows the case where the central portion of the substrate 1 is exposed, and the optical axis coincides with the center of the substrate 1. On the other hand, FIG. 2B shows a case where the vicinity of the outer periphery of the substrate 1 is exposed, and the optical axis is shifted from the center of the substrate 1.
[0036]
When the projection optical system and the illumination optical system form an equal-size erect image, the coordinates of the center of the substrate 1 are (Xw, Yw) and the coordinates of the center of the opening of the circular masking blade 3 are (Xm, Ym). The control device 51 performs, in each shot,
Xm = Xw
Ym = Yw
The XY positions of the substrate 1 and the circular masking blade 3 are controlled so that
[0037]
When the image is inverted or the magnification is changed by the projection optical system or the illumination optical system, the controller 51 inverts the sign in the above equation or multiplies the magnification so that the center of the opening of the circular masking blade 3 Control is performed to match the center.
[0038]
2A and 2B, a region where light has passed through the circular masking blade 3 and the mask 2 is a projection exposure region on the substrate 1. On the other hand, in FIG. 2B, a region where light is blocked by the circular masking blade 3 is an unexposed portion on the substrate 1.
[0039]
FIG. 3 is a top view showing the positional relationship between the substrate and the opening of the circular masking blade. FIG. 3 shows, as an example, a case where the imaging magnification of the projection optical system and the illumination optical system is the same, and exposure of the entire substrate and formation of an unexposed portion near the outer periphery are performed in nine shots.
[0040]
The center of the shot moves nine points by the step movement of the substrate. In each shot, the center of the opening of the circular masking blade 3 coincides with the center of the substrate 1. The diameter of the opening of the circular masking blade 3 is slightly smaller than the diameter of the outer periphery of the substrate 1. On the surface of the substrate 1, light passes through the inside of the opening position of the circular masking blade 3 to form a projection exposure area, and the outside blocks light to block unexposed portions.
[0041]
The diameter of the opening of the circular masking blade 3 is a value obtained by subtracting twice the width of the unexposed portion from the diameter of the substrate 1 and is a fixed value. The diameter of the opening of the circular masking blade 3 does not depend on the shot size and the number of shots. Thus, the same circular masking blade can be applied to any shot size and number of shots.
[0042]
FIG. 3 shows a case where exposure of the entire substrate and formation of an unexposed portion near the outer periphery are performed by nine shots. The circular masking blade 3 may be moved only when the substrate is moved, and the movement of the circular masking blade 3 may be omitted for a shot that does not reach near the outer periphery of the substrate. Thereby, the throughput can be further improved.
[0043]
The projection optical lens usually includes a plurality of lens groups. In order to increase the processing capacity by increasing the shot size of the step-type projection exposure apparatus, a projection lens having a high precision and a wide projection exposure area is required. It is very difficult to make. Therefore, a scanning projection exposure apparatus that uses a projection lens in a small projection exposure area and synchronously scans a substrate and a mask relative to the projection lens is known. However, in a scanning projection exposure apparatus, if the range of the scanning exposure is too wide, a very large mask is required, and the cost of the mask increases. To balance these, there is a step-and-scan projection exposure apparatus in which a mechanism for stepping a substrate is added to a scanning projection exposure apparatus.
[0044]
FIG. 4 is a diagram showing a schematic configuration of a projection exposure apparatus according to another embodiment of the present invention. This embodiment shows an example of a step-and-scan projection exposure apparatus that performs one-dimensional scanning exposure. The projection exposure apparatus includes a mask 2, a circular masking blade 3, a substrate chuck 5, an XYZθ stage 6, a laser light source 10b, mirrors 12, 17, a shutter 13, a fly-eye lens 14, an illumination σ diaphragm 15, an illumination condenser lens 16, It includes an image lens 18, a projection lens 19, a scanning mechanism 22, a scanning / XY moving mechanism 32, and a control device 52. In FIG. 4, an optical system, an alignment mechanism, and the like for aligning a circuit pattern already formed on the substrate with a mask pattern are omitted. The same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
[0045]
In the step-and-scan projection exposure apparatus shown in FIG. 4, a laser light source 10b such as an excimer laser is used as a light source for exposure. The scan mechanism 22 is attached to the mask stage on which the mask 2 is mounted. Further, a scan / XY moving mechanism 32 is attached to the circular masking blade 3.
[0046]
At the time of scanning exposure in each shot, the control device 52 drives the XYZθ stage 6 and the scanning mechanism 22 to move the substrate 1 and the mask 2 relative to the projection lens 19 in the Y direction (or X direction). Scan synchronously. At this time, the control device 52 drives the scan / XY moving mechanism 32 to scan the circular masking blade 3 in synchronization with the substrate 1 to keep the relative position between the substrate 1 and the opening of the circular masking blade 3 constant. I do.
[0047]
When one shot is completed, the control device 52 drives the XYZθ stage 6 to move the XY position of the substrate 1 stepwise. Further, the control device 52 drives the scan / XY moving mechanism 32 to move the XY position of the circular masking blade 3 so that the relative position between the substrate 1 and the opening of the circular masking blade 3 is kept constant. The movement of the circular masking blade 3 may be performed after the movement of the substrate 1, or may be performed in synchronization with the movement of the substrate 1. When the circular masking blade 3 is moved in synchronization with the movement of the substrate 1, the movement time is shortened, and the throughput can be further improved. After the movement of the substrate 1 and the circular masking blade 3, the next shot is performed, and by repeating these operations, the entire substrate 1 is exposed.
[0048]
In the embodiment shown in FIG. 4, scanning of the circular masking blade 3 during scanning exposure and movement of the circular masking blade 3 accompanying the step movement of the substrate 1 are performed by the scan / XY moving mechanism 32. However, these may be performed by providing separate mechanisms.
[0049]
According to the embodiment shown in FIG. 4, by performing the scanning exposure in the one-dimensional direction, it is possible to expose a wide range using a projection lens in a small projection exposure area.
[0050]
FIG. 5 is a diagram showing a schematic configuration of a projection exposure apparatus according to still another embodiment of the present invention. This embodiment shows an example of a step-and-scan projection exposure apparatus that performs two-dimensional scanning exposure. The projection exposure apparatus includes a mask 2, a circular masking blade 3, a substrate chuck 5, an XYZθ stage 6, a mercury lamp 10a, an elliptical mirror 11, mirrors 12, 17, a shutter 13, a fly-eye lens 14, an illumination σ diaphragm 15, an illumination condenser lens. 16, an illumination imaging lens 18, a projection lens 19, XY moving mechanisms 23 and 33, a projection optical system 40, and a control device 53. In FIG. 5, an optical system, an alignment mechanism, and the like for aligning the circuit pattern already formed on the substrate with the pattern of the mask are omitted. The same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.
[0051]
In the step-and-scan projection exposure apparatus shown in FIG. 5, a projection optical system 40 described later is used. An XY moving mechanism 23 is attached to the mask stage on which the mask 2 is mounted. An XY moving mechanism 33 is attached to the circular masking blade 3.
[0052]
In each shot, at the time of scanning exposure, the control device 53 drives the XYZθ stage 6 and the XY moving mechanism 23 to move the substrate 1 and the mask 2 relative to the projection optical system 40 in the X direction and the Y direction. Scan synchronously. At this time, the control device 53 drives the XY moving mechanism 33 to scan the circular masking blade 3 in synchronization with the substrate 1 and keeps the relative position between the substrate 1 and the opening of the circular masking blade 3 constant.
[0053]
FIG. 6 is a diagram showing a schematic configuration of a projection optical system according to an embodiment of the present invention. The wavelengths of the light of the mercury lamp 10a that contribute to the exposure are three wavelengths: g-line (436 nm), h-line (404 nm), and i-line (365 nm). Therefore, in the present embodiment, in order to obtain higher illuminance, a projection optical system of a 1 × erect image that can use three wavelengths of g-line, h-line, and i-line is used.
[0054]
The projection optical system 40 includes triangular mirrors 41a and 41b, combination lenses 42a and 42b, NA stops 43a and 43b, concave mirrors 44a and 44b, and an exposure area stop 46. The combination lenses 42a and 42b are mounted in lens barrels 48a and 48b, respectively, and concave mirrors 44a and 44b are mounted on tips of movable parts of the lens barrels 48a and 48b, respectively. The lens barrels 48a and 48b are supported by a support block 47.
[0055]
The basic characteristics of the projection optical system 40 according to the present embodiment are determined by the processing accuracy of the combination lenses 42a and 42b and the concave mirrors 44a and 44b and the relative positions. Therefore, optical precision adjustment is performed for each of the lens barrels 48a and 48b. FIG. 7 is a diagram showing a relative position of the projection optical system of FIG. In the present embodiment, for example, G = 49.5 mm, H = 75 mm, and L = 450 mm.
[0056]
6 and 7, light incident from the mask surface is reflected by the triangular mirror 41a, and reaches the concave mirror 44a through the combination lens 42a and the NA diaphragm 43a. The illumination light reflected by the concave mirror 44a reaches the triangular mirror 41a through the NA diaphragm 43a and the combination lens 42a. The illumination light reflected by the triangular mirror 41a forms an image on the first image plane. The concave mirror 44a is arranged on the first pupil plane, and the mask plane and the first imaging plane are arranged symmetrically with respect to the first pupil plane.
[0057]
An exposure area stop 46 is provided on the first image plane, and the illumination light passing through the exposure area stop 46 is reflected by the triangular mirror 41b, reaches the concave mirror 44b through the combination lens 42b and the NA stop 43b. I do. The illumination light reflected by the concave mirror 44b reaches the triangular mirror 41b through the NA diaphragm 43b and the combination lens 42b. The illumination light reflected by the triangular mirror 41b forms an image on the second image plane. The concave mirror 44b is arranged on the second pupil plane, and the substrate surface is arranged on the second imaging plane. The first image plane and the substrate surface (second image plane) are arranged symmetrically with respect to the second pupil plane.
[0058]
When a concave mirror is used instead of a lens in the projection optical system, chromatic aberration due to a difference in wavelength of illumination light does not occur. Therefore, projection exposure using more wavelengths becomes possible. However, the concave mirror has a spherical aberration, and as it is, a focus position error occurs in the radius method of the spot of the illumination light and in the circumferential direction. Therefore, in the present embodiment, the focal position error is corrected by the combination lens. Each of the combination lenses 42a and 42b includes a concave lens made of a single optical glass and a convex lens. The convex lens is an achromatic lens composed of three types of lenses made of different optical glasses.
[0059]
The combination lenses 42a and 42b are movable in the optical axis direction within the lens barrels 48a and 48b, and the focus position and the projection magnification are adjusted by adjusting the distance between the lenses constituting the combination lenses 42a and 42b. can do. When adjusted to the design position in the above-described example, the magnification is completely 1 at the best focus, and asymmetric aberrations such as coma become zero.
[0060]
FIG. 8 is a diagram showing a projection exposure area of the projection optical system of FIG. Since the projection optical system 40 uses a concave mirror, the area where projection exposure is possible is semicircular. In the semicircle, the range of the predetermined distance E from the center line of the circle is excluded from the projection exposure possible area because the shadow of the boundary line between the triangular mirrors 41a and 41b is formed. The exposure area stop 46 sets a trapezoidal projection exposure area as shown in FIG. In the present embodiment, for example, A = 39 mm, B = 43 mm, C = 47 mm, D = 9.5 mm, E = 4.5 mm, and R = 24 mm (diameter 48 mm). The exposure area stop 46 is provided on the first image plane and is movable in the XY directions. By moving the exposure area stop 46 in the X and Y directions, the position of the projection exposure area can be adjusted.
[0061]
According to the projection optical system shown in FIG. 6, by using a projection optical system including a concave mirror and a combination lens, the number of required lenses is reduced, and light absorption and reflection by the lenses are reduced. In addition, chromatic aberration is corrected by the achromatic convex lens, and projection exposure using more wavelengths becomes possible. Therefore, projection exposure with high illuminance and high contrast can be performed. Further, the cost of the projection optical system can be greatly reduced, and the cost of the apparatus can be reduced.
[0062]
Note that the projection optical system shown in FIG. 6 adjusts the size of the projection exposure area and the shot size to perform the one-dimensional scanning exposure shown in FIG. Can also be applied.
[0063]
FIG. 9 is a view for explaining the scanning exposure operation of the projection exposure apparatus of FIG. In FIG. 5, when the substrate 1 and the mask 2 are synchronously scanned in the Y direction relative to the projection optical system 40, the projection exposure area of the projection optical system 40 moves relatively on the substrate 1 in the Y direction. Perform exposure. In the example of FIG. 9, in the first scan, a complete exposure range where exposure is completed, a semi-exposure range where exposure is performed intermediately, and an unexposed range where exposure is not performed are obtained. In FIG. 8, a portion of the projection exposure region scanned by the region of width A is a complete exposure range of the first scan, and a portion of the projection exposure region scanned by the remaining region is a half exposure range of the first scan. .
[0064]
Next, the substrate 1 and the mask 2 are moved in the X direction. The moving distance is the same as the dimension B shown in FIG. Then, the substrate 1 and the mask 2 are synchronously scanned in the Y direction relative to the projection optical system 40, and a second scan is performed. The half-exposure range of the first scan is overlaid by the second scan, so that it is finally completely exposed. In this manner, the range of one shot is uniformly exposed by a plurality of scans.
[0065]
In FIG. 5, when one shot is completed, the control device 53 drives the XYZθ stage 6 to move the XY position of the substrate 1 stepwise. Further, the control device 53 drives the XY moving mechanism 33 to move the XY position of the circular masking blade 3 so that the relative position between the substrate 1 and the opening of the circular masking blade 3 is kept constant. The movement of the circular masking blade 3 may be performed after the movement of the substrate 1, or may be performed in synchronization with the movement of the substrate 1. When the circular masking blade 3 is moved in synchronization with the movement of the substrate 1, the movement time is shortened, and the throughput can be further improved. After the movement of the substrate 1 and the circular masking blade 3, the next shot is performed, and by repeating these operations, the entire substrate 1 is exposed.
[0066]
In the embodiment shown in FIG. 5, the scanning of the circular masking blade 3 during the scanning exposure and the movement of the circular masking blade 3 accompanying the step movement of the substrate 1 are performed by the XY moving mechanism 33. However, these may be performed by providing separate mechanisms.
[0067]
According to the embodiment shown in FIG. 5, by performing the scanning exposure in the two-dimensional direction, it is possible to expose a wide range using the projection optical system of a smaller projection exposure area.
[0068]
The embodiment shown in FIG. 5 is an example of a step-and-scan type projection exposure apparatus. However, when the mask 2 is enlarged using the same projection optical system 40, the entire substrate 1 is exposed by one shot. It becomes a scanning type projection exposure apparatus. In this case, it is not necessary to move the substrate 1 stepwise by the XYZθ stage 6, and it is not necessary to move the circular masking blade 3 by the XY moving mechanism 33 accordingly. Others are the same as those of the projection exposure apparatus shown in FIG. Further, when a plurality of projection optical systems 40 are provided, the entire exposure time is shortened, and the throughput can be further improved.
[0069]
In the embodiment described above, the circular masking blade 3 is a plate having a circular opening. However, according to the present invention, the blocking unit that blocks light emitted to the vicinity of the outer periphery of the substrate is provided with a center around the circular opening. May be partly divided into n parts along. In this case, a θ movement mechanism is added to each of the XY movement mechanism 31 in FIG. 1, the scan / XY movement mechanism 32 in FIG. 4, and the XY movement mechanism 33 in FIG. By rotating the blocking means in this manner, the same operation as the circular masking blade 3 can be performed.
[0070]
FIG. 10 is a flowchart showing an outline of the device manufacturing process. The device manufacturing process is roughly divided into the following six processes.
(1) Design process (Step 110)
The work of designing a device, including the steps of logic design, circuit design, layout design, and test design.
(2) Mask manufacturing process (Step 120)
The operation of manufacturing a mask includes processes such as mask blank manufacturing, pattern formation, correction, and inspection.
(3) Substrate manufacturing process (Step 130)
An operation of manufacturing a substrate such as a semiconductor wafer, which includes processes such as single crystal manufacturing, cutting, and polishing.
(4) Substrate processing step (pre-process) (step 140)
An operation of forming a chip on a substrate, including processes such as cleaning, oxidation, thin film formation, ion implantation, and pattern formation.
(5) Assembly process (post-process) (step 150)
The process of converting a chip on a substrate into a device, including processes such as dicing, bonding, packaging, finishing, and marking.
(6) Inspection process (Step 160)
In product inspection, product inspection, reliability test, etc. are performed.
[0071]
FIG. 11 is a flowchart when a pattern is formed in the substrate processing step. First, a resist is applied to the substrate surface (Step 210). Next, the pattern of the mask is exposed onto the substrate using the projection exposure apparatus of the present invention (step 220). Subsequently, a resist pattern is formed by a development process (Step 230). Subsequently, a circuit pattern is formed by etching using the resist pattern as a mask (step 240). Finally, the resist is peeled off and removed (step 250). By repeating these processes, a complicated circuit pattern is formed on the substrate.
[0072]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the throughput of the operation | work which exposes a circuit pattern while forming an unexposed part near the outer periphery of a circular board | substrate can be improved. By forming an unexposed portion near the outer periphery of the substrate, peeling of the circuit pattern can be prevented, and the yield of the device is improved.
[0073]
In addition, according to the device manufacturing method of the present invention, the throughput of the operation of forming a circuit pattern is improved, so that the device manufacturing cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing a schematic configuration of a projection exposure apparatus according to an embodiment of the present invention.
FIG. 2 is a side view showing a positional relationship between a substrate and an opening of a circular masking blade.
FIG. 3 is a top view showing a positional relationship between a substrate and an opening of a circular masking blade.
FIG. 4 is a diagram showing a schematic configuration of a projection exposure apparatus according to another embodiment of the present invention.
FIG. 5 is a diagram showing a schematic configuration of a projection exposure apparatus according to still another embodiment of the present invention.
FIG. 6 is a diagram showing a schematic configuration of a projection optical system according to an embodiment of the present invention.
7 is a diagram showing a relative position of the projection optical system of FIG.
8 is a diagram showing a projection exposure area of the projection optical system of FIG.
FIG. 9 is a diagram illustrating a scanning exposure operation of the projection exposure apparatus of FIG.
FIG. 10 is a flowchart showing an outline of a device manufacturing process.
FIG. 11 is a flowchart when a pattern is formed in a substrate processing step.
FIG. 12 is a view showing a schematic configuration of a conventional step type projection exposure apparatus.
[Explanation of symbols]
1 ... substrate
2 ... Mask
3 ... Circular masking blade
5 ... substrate chuck
6 XYZθ stage
10a: Mercury lamp
10b ... Laser light source
11 ... elliptical mirror
12, 17… Mirror
13 ... Shutter
14 ... Fly eye lens
15 ... Lighting σ stop
16 Lighting condenser lens
18. Illumination imaging lens
19 ... Projection lens
22 ... Scan mechanism
23, 31, 33 ... XY moving mechanism
32 ... Scan / XY movement mechanism
40 Projection optical system
41a, 41b ... triangular mirror
42a, 42b ... combination lens
43a, 43b ... NA aperture
44a, 44b ... concave mirror
46 ... Exposure area stop
51, 52, 53 ... control device

Claims (18)

A projection exposure apparatus that includes a projection optical system and projects a mask pattern onto a circular substrate,
A projection exposure apparatus comprising: a circular opening or a part thereof; and a blocking unit that blocks light emitted to the vicinity of the outer periphery of the substrate. First moving means for step-moving the substrate;
2. The projection light apparatus according to claim 1, further comprising: a second moving unit that moves the light shielding unit so as to keep a relative position between the substrate and the opening of the light shielding unit constant. 3. The projection exposure apparatus according to claim 2, wherein the second moving unit moves the light blocking unit in synchronization with the movement of the substrate by the first moving unit. The second moving unit is configured to maintain a relative position between the substrate and the opening of the light shielding unit constant when the first moving unit moves the substrate to a shot position for exposing the periphery of the substrate. 3. The projection exposure apparatus according to claim 2, wherein the light shielding means is moved. Scanning means for synchronously scanning the substrate and the mask in a one-dimensional direction relative to the projection optical system;
3. The projection exposure apparatus according to claim 2, further comprising a third moving unit that moves the light shielding unit in synchronization with the scanning of the substrate by the scanning unit. The projection exposure apparatus according to claim 5, wherein the third moving unit also serves as the second moving unit. Scanning means for synchronously scanning the substrate and the mask in a two-dimensional direction relative to the projection optical system;
3. The projection exposure apparatus according to claim 2, further comprising a third moving unit that moves the light shielding unit in synchronization with the scanning of the substrate by the scanning unit. 8. The projection exposure apparatus according to claim 7, wherein the third moving unit also serves as the second moving unit. Scanning means for synchronously scanning the substrate and the mask in a two-dimensional direction relative to the projection optical system;
2. The projection exposure apparatus according to claim 1, further comprising: a unit that moves the light shielding unit in synchronization with scanning of the substrate by the scanning unit. The projection optical system includes a concave mirror, a combined lens including a concave lens made of a single optical glass, and an achromatic convex lens made up of three types of lenses made of different optical glasses, and a 1: 1 erect image of a mask pattern is formed on a substrate. 10. The projection exposure apparatus according to claim 5, wherein the projection is performed upward. A projection exposure method for projecting a mask pattern onto a circular substrate using a projection optical system,
A projection exposure method, comprising using a light-shielding means having a circular opening or a part thereof to block light emitted to the vicinity of the outer periphery of a substrate and forming an unexposed portion near the outer periphery of the substrate. Expose the entire substrate with multiple shots,
12. The projection light method according to claim 11, wherein when the substrate is moved to the position of each shot, the light shielding means is moved so as to keep the relative position between the substrate and the opening of the light shielding means constant. Expose the entire substrate with multiple shots,
12. The projection according to claim 11, wherein when the substrate is moved to a shot position for exposing the vicinity of the outer periphery of the substrate, the light shielding means is moved so as to keep a relative position between the substrate and the opening of the light shielding means constant. Exposure method. Each shot is performed by synchronously scanning the substrate and the mask in a one-dimensional direction relative to the projection optical system,
14. The projection exposure method according to claim 12, wherein the light shielding unit is moved in synchronization with scanning of the substrate. Each shot is performed by synchronously scanning the substrate and the mask in the two-dimensional direction relative to the projection optical system,
14. The projection exposure method according to claim 12, wherein the light shielding unit is moved in synchronization with scanning of the substrate. Exposure of the entire substrate is performed by synchronously scanning the substrate and the mask in a two-dimensional direction relative to the projection optical system,
The projection exposure method according to claim 11, wherein the light shielding means is moved in synchronization with the scanning of the substrate. Using a projection optical system including a concave mirror and a combination lens including a concave lens made of a single optical glass and an achromatic convex lens made up of three kinds of lenses made of different optical glasses, an equal-size erect image of the pattern of the mask is formed. 17. The projection exposure method according to claim 14, wherein the projection is performed on a substrate. A device manufacturing method, comprising a step of forming a circuit pattern using the projection exposure method according to any one of claims 11 to 17.

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