JPS62285420A - Aligner - Google Patents

Abstract

PURPOSE:To project a beam of alignment light in an exposure light flux from outside or take it out therefrom, to facilitate alignment and to make an aligner small in size, by a construction wherein a spectoscopic means of reflecting a beam of exposure light and transmitting the beam of alignment light which is a non-printing light is disposed between a projection lens and a negative plate. CONSTITUTION:A pattern of a reticle 1 is projected onto the surface of a wafer 2 by means of a projection lens 3 and a dichroic film 4 of parallel-plate glass of an aligner and exposed. Exposure lights separated by this dichroic film 4 are combined in an alignment detection system constituted by first and second microscope blocks 8 and 9. In this block 9, a coma compensating plate 20, a field lens 21, a telecontric compensating lens 22, an astigmatism and coma correction lens 25, an imaging lens 27, etc. are provided. While the exposure light is reflected, an alignment light, which is a non-printing light, is transmitted and projected in an exposure light flux from outside or taken out therefrom, alignment is facilitated, and the aligner is made small in size.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an exposure apparatus used in a photolithography process in the manufacturing process of semiconductor devices such as ICs and LSIs.

A specific example is an apparatus that uses a projection optical system to project and expose a pattern on a reticle onto a semiconductor substrate (wafer), and includes alignment optics for positional alignment between the pattern on the reticle and the pattern on the semiconductor substrate. The present invention relates to an exposure apparatus in which a system and the entire apparatus including a projection optical system are matched.

[Prior Art] Many proposals have been made regarding alignment in exposure devices (so-called steppers) using reduction lenses, and these have been applied to products. The intent of these proposals and product applications is to determine how accurately the pattern on the reticle is aligned with the pattern on the wafer through a projection lens, and then exposed. ■The aim is to achieve the process more reliably and faster than ■. Furthermore, if I were to add one more condition, I would like to add one more condition: (1) The ease of use can be improved.

However, it is difficult to achieve all of these conditions to a satisfactory level, and the proposals and application examples that have been made so far usually have drawbacks in one or another of the items.

This drawback can be said to be a fateful weakness of steppers that use projection lenses, but when we analyze the problem, we come to the following reasoning. In other words, (a) Before projecting and exposing the reticle pattern onto the wafer pattern via the projection lens, in order to perform relative positioning of the projected image of the reticle pattern and the wafer pattern more accurately than r, Alignment through a projection lens is preferred. In other words, TTL alignment is desirable.

(b) In order for light carrying the positional information of the reticle or wafer mark to pass through the projection lens, it must be effective as an information medium because of the aberrations that occur there. Something becomes inevitable.

(8) As common sense, an alignment mark has a step structure with unevenness, so when light with a narrow wavelength width is applied here, the light reflected from the upper edge of the unevenness and the light reflected from the lower edge are different. cause interference. Therefore, depending on the amount of the step and the refractive index of the resist applied there, the signal light may be reduced or disappear. Therefore, in order to reliably perform one alignment under any process conditions, it is necessary to perform alignment using a plurality of alignment lights of different wavelengths.

(:) If light with the same wavelength as the exposure wavelength is used as alignment light, chromatic aberration due to the projection lens will not occur and the tickle mark and square mark can be observed simultaneously as two-dimensional images without the need for an additional optical system. Therefore, it is appropriate to use the exposure wavelength as one of the alignment wavelengths.

(e) Other alignment lights must have a wavelength different from the exposure wavelength. At this time, the chromatic aberration that occurs when non-exposure light having a wavelength different from the exposure wavelength is transmitted through the lens can be analyzed into several types of aberrations in optical theory. However, in the proposals and application examples so far, only longitudinal chromatic aberration has been corrected.

This means that only marks oriented in the sagittal direction (radial direction with respect to the lens optical axis) can be used, and therefore only the direction component orthogonal to the mark can be detected.For example, in order to align the XY directions, two A microscope containing two objective lenses is required.

(f) The disadvantages caused by restricting the position of the alignment mark with respect to the projection lens appear in various forms.

(i) For example, in a case where alignment marks can only exist on the XY coordinate axes with the lens optical axis as the origin, if it becomes necessary to update the alignment marks on the wafer side, the projection lens On the other hand, the only option is to shift and set the actual element pattern part. However, in this case, a portion of the actual element pattern portion is shifted out of the effective screen of the projection lens, so that the effective screen of the projection lens is substantially damaged.

(ii) In order to avoid the above situation, there is a method of quantitatively shifting the position where the actual element pattern portion overlaps and the position where the alignment mark overlaps in the relationship between the reticle and the square. However, in this case, it is necessary to move the wafer or reticle by a certain amount of 8wJ after alignment and before exposure, and this 9-shift time impairs rspeedj, and the movement accuracy reduces raccuracy1. be damaged.

(g) On the other hand, when using a non-exposure wavelength as alignment light, the light emitted from a single point on the wafer side (image surface side) usually forms an image farther away than the reticle pattern surface (object surface) due to axial chromatic aberration. do. If this light is to be captured at the position where it passes through the reticle, the reticle will need a large window to allow this light beam to pass through.

In order to avoid this, it is necessary to extract the light carrying the signal to the sea urchin to the outside of the exposure light beam between the reticle and the lens. However, in order to extract this signal, a mirror or an equivalent optical member is required in the exposure beam, and if this mirror is fixed, it will impair the effective field of the lens. Furthermore, if this mirror is withdrawn from the exposure light beam every time exposure is performed, the position reproducibility of this mirror will impair alignment accuracy.

(H) As described in (G) above, several methods have been proposed in which the extracted light is taken into a microscope containing an objective lens, and this is converted into an electrical signal to perform alignment.

As an example, there is an example in which a temporary reference is provided in the microscope and the relative position of the wafer mark is aligned with this reference. In this case, inclusions will be present in the alignment of the reticle and wafer, which is a wooden objective, and this will be a factor that impairs r accuracy 1.

[Problems to be Solved by the Invention] A first object of the present invention is to provide a reduction projection exposure apparatus that
The object of the present invention is to solve the various drawbacks and problems mentioned above and to provide an improved alignment method and alignment device.

A second object of the present invention is to provide an exposure apparatus with higher precision and multifunctionality in order to meet the more advanced demands of miniaturization, higher integration, and higher speed of semiconductor devices.

Possible situations and requirements for providing an exposure apparatus with higher precision and multifunctionality as described above will be described below.

Dynamic RAM (DRAM)
), IM bit DRAMs are currently entering mass production, and are designed using approximately 1 μm design rules. In the future, 4M bit DRAM and 16M
When it comes to bit DRAM, the design rule is 0.
From 7 μm to 0.5 μm, we are entering the so-called submicron process era. Exposure equipment is first required to have high resolving power, and for this purpose the exposure wavelength has changed from the current g-line to 1-line, and furthermore to 308 nm and 24 nm of excimer laser.
The wavelength will continue to be shortened to 9 nm.

Using a single wavelength of exposure light has an advantageous effect on resolving power and depth of focus, but when designing a projection lens, there is an emphasis on resolving power (
In other words, it is inevitable that the NA will increase. As a result, the depth of focus will be at a level of around ±1 μm in practical resolution.

It is known that the focus position changes with temperature and atmospheric pressure, but it also changes with exposure light irradiation. TTL focusing is effective in maintaining stable resolution accuracy in such situations. The method of capturing a TTL focus signal is similar to that of capturing an AA (auto alignment) signal.

Furthermore, when looking into the depth issue, warping of the surface of the sea urchin becomes a problem, and in this case, TTL focus at three points within the exposure screen and a tilt mechanism on the wafer side are required.

On the other hand, the apparatus is required to improve the overlay accuracy as well as improve the resolution. It is said that the required overlay accuracy is about 1/3 to 115 times the device design rule. Overlay accuracy depends on factors such as magnification,
Can be separated into distortion and alignment accuracy. The alignment is in the 'direction parallel to the image plane
It is assumed that the reticle projected image and the pattern on the wafer are aligned relative to each other in the Yθ direction so that they completely overlap, but if there is relative magnification distortion between the reticle projected image and the wafer pattern, this Alignment cannot help.

Distortion as a random component or a nonlinear component with respect to the absolute lattice requires efforts to bring it closer to the absolute lattice as a design and manufacturing technique of the projection lens.

On the other hand, it is known that the magnification, which is an expansion/contraction component proportional to the distance from the optical axis of the projection lens, changes depending on atmospheric pressure, and also changes depending on temperature and exposure. Furthermore, on the wafer side, expansion and contraction of the pattern occurs due to heating processes and the like.

Therefore, in an era when overlay accuracy of 0.1 μm or less is required, devices will be required to have a function of detecting and correcting magnification in real time.

Considering the above situation, the exposure equipment that supports the sub-micron process era not only improves alignment accuracy, but also detects error factors on both the process side and the equipment side for focus, one-sided blur, and magnification. However, a correction function is required.

[Means and effects for solving the problem] In the first invention, the exposure light is substantially reflected and alignment light, which is non-printing light, is provided between the projection lens of the exposure device and the original plate such as a reticle. By arranging a substantially transparent spectroscopic means, alignment light is input from the outside into the exposure light beam, and
Furthermore, it is possible to take out the light outside the exposure light beam.

Further, in the second invention, a spectroscopic means is disposed between the projection lens of the exposure device and the original plate such as a reticle, which substantially reflects the exposure light and substantially transmits the alignment light, which is non-printing light. Up to this point, the present invention is the same as the first invention, but it further includes a first optical system and a second optical system that can simultaneously observe the alignment marks on the original plate side and the alignment marks on the photosensitive substrate side. This makes it possible to detect deviations in the standard due to changes in process conditions over time.

The third invention includes an optical system that is a TTL focus detection system, making it possible to obtain uniform and good resolution performance over the entire exposure screen.

[Embodiment] FIG. 1 shows a conceptual diagram of an alignment detection system, an alignment drive system, and a magnification correction drive system in an exposure apparatus according to an embodiment of the present invention. 3A shows a side view, and FIG. 1B shows a plan view of the reticle portion.

In the figure, a projection lens 3 and a dichroic mirror 4 are arranged to project and expose the pattern of a reticle 1 onto the surface of a wafer 2. The projection lens 3 is telecentric on the wafer 2 side, and has a single telecentric system. The dichroic mirror 4 on the parallel flat glass 5 is set at an angle of 45 degrees with respect to the projection optical axis, and the projection optical axis is bent by 90 degrees at the dichroic mirror 4 section. Exposure light is reflected by this dichroic mirror 4 in a direction of 90°, and light having a wavelength for alignment and autofocus is transmitted through the dichroic mirror 4.

The reticle 1 is suctioned and fixed to the reticle holding plate 6. The wafer 2 is held on two movable stages 7. Exposure is performed by illuminating the reticle 1 with an illumination optical system (not shown) located on the right side of the reticle 1 in the figure.

The alignment detection system can be divided into two blocks: the first microscope 8 and the auxiliary optical system 9. In FIG. 1, the optical system is shown expanded on one plane for ease of understanding. Furthermore, in reality, the optical system shown in FIG. 1(a) is assumed to have two groups of identical optical systems arranged in the depth direction of the drawing. Furthermore, for ease of understanding, the coordinate system is such that the projection optical axis is the Z axis, and the X and Y axes are set on a plane orthogonal thereto, as shown in FIG. 1(b).

Configuration of First Microscope> The first microscope 8 uses two alignment lights. The first light source is a HeNe laser (wavelength 633n
m) 30, and the second light source is one in which light at the exposure wavelength is guided by a light guide 10 from an exposure illumination optical system (not shown). These 2f! For similar types of light, beam splitter 1
1, the HeNe light is transmitted, and the light at the exposure wavelength is reflected and reaches the illumination lens 12. The light transmitted through the illumination lens 12 is bent by the beam splitter 13 and then passes through the objective lens 14.
Then, the pattern surface 16 of the reticle 1 is irradiated.

Conversely, the light reflected by the reticle 1 or the wafer 2 passes through the objective lens 14, passes through the beam splitter 13, and forms an image on the image sensor 15. Here, it goes without saying that the objective lens 14 has aberrations corrected for two wavelengths: exposure light and HeNe light (833 nm). In addition, it has an aperture that can cover changes in the incident angle due to changes in the image height of the exposure light.

By moving the entire microscope, the first microscope 8
Reticle set marks a17, 17' shown in figure (b)
, the reticle-side alignment marks 18° and 18', and most of the exposed area 19 are configured to be observable.

Purpose and configuration of the auxiliary optical system> The purpose of the auxiliary optical system 9 is to guide the HeNe laser beam projected by the first microscope 8 and transmitted through the reticle side alignment mark 18, 18' to the alignment mark portion MW on the wafer 2 side. Conversely, the HeNe light reflected by the MW is focused on the reticle pattern surface 16 of the reticle-side alignment mark portion 18, 18' by correcting the aberrations generated by the projection lens 3 and the parallel plane glass 5.

The configuration will be described below while tracing the light reflected from the alignment mark portion MW on the wafer. The light reflected from the alignment mark portion MW passes through the projection lens 3 and reaches the dichroic mirror 4. If a mirror that also reflects the alignment light is placed in place of the dichroic film, this light will pass through the reticle pattern surface 16 due to the axial chromatic aberration caused by the projection lens 3 and will form an image at a point P located at a distance A from there. do. For example, the value of the distance 111i A is several tens of liters when HeNe light (wavelength 633 nm) is passed through an i-line lens. If you try to do so, the reticle pattern section 1
6 requires a large window, but the existence of such a window is practically unacceptable.

This is the reason why the signal light of the wafer 2 is temporarily taken out of the exposure light beam between the reticle 1 and the projection lens 3. Now, the light that has passed through the dichroic mirror 4 and the parallel plane glass 5 has the coma aberration caused by passing through the parallel plane glass 5 returned to normal light by the coma correction plate 20, and the field lens 21 converts the principal ray due to the image height. The inclination is adjusted in a uniform direction, and the subsequent telecentricity correction lens 22 corrects out-of-focus due to image height. The corrected light is sent to mirrors 23, 24. Ayucoma correction optical system 25. Mirror 26. After passing through the imaging lens 27 and mirrors 28 and 29, the alignment mark 1 on the reticle side
8, 18'.

The function of the ascoma correction optical system 25 is explained in detail in the specification of the application titled "Observation device 1 (inventor: Akiyoshi Suzuki)" filed on May 30, 1986 by the present applicant. There is.

The imaging lens 27 is used to re-image the light that has been imaged in the air onto the reticle-side alignment mark portion 18, 18'. Further, the field lens 21 is arranged at a position such that the magnification of the alignment light on the imaging plane is equal to the magnification of the exposure light. The auxiliary optical system 9 is configured to be able to observe a limited range of the image plane side region corresponding to the exposure possible region 19 by moving the optical components.

When the observation range moves along the X-axis, only the entire auxiliary optical system 9 except the field lens 21 and the telecentricity correction lens 22 needs to move. When moving the observation position in the Y-axis direction, the mirrors 24 and 28 and the ascoma correction optical system 25 are integrally moved by ΔY/2 in the same direction for the 9-axis amount ΔY of the coma correction plate 20 and mirror 23, and the optical path is changed. It is necessary to correct the length. When moving the observation position, the optical components are moved 8 times, but if the coma correction plate 20 and mirrors 28 and 29 have an area that covers the observation range, it is necessary to move the optical components 8 times while keeping them fixed. There isn't.

Next, the functions when using these detection optical systems will be explained along with the procedure for actually using the apparatus.

◎ [Reticle Set-1] When a new reticle is set in the exposure device, it is necessary to set the reticle in accordance with the standards of the device. To do this, first move the entire first microscope 8 or a part of the optical part including the objective lens 14 to mark the reticle set mark a.
17. Move to a position where 17' can be observed. There is a reticle reference mark (not shown) fixed to the apparatus side in close proximity to the reticle pattern surface 16 of the reticle set mark a, 17, 17', and alignment is performed using both marks. The light used at this time is HeN even if it is exposure light.
Either e-light may be used, or both may be used.

◎ [Reticle Set-2] Reticle setting can also be performed with respect to the stage-side reference plate 31 attached to the wafer stage 7. In the case of ;, first, the stage 7 is moved so that the center of the reference plate 31 is on the optical axis of the projection lens 3. On the other hand, the first microscope 8 has a reticle set mark b 32.32
' moves to a position where it can be observed. Two reticle alignment marks 35.35' are arranged on the reference plate 31 as shown in FIG.
=S/lens reduction magnification.

By using the exposure light illumination and detection system of the first microscope 8, the reticle set mark 32 and the reticle alignment mark 35 are
The XYθ alignment of the reticle 1 can be performed while simultaneously observing the left and right marks of the marks 32' and 35'. Further, at this time, the magnification β of the lens can be detected from the runout values of the two detection systems. Note that the correction of the magnification β will be described later.

◎ [Exposure light, on-axis alignment] First microscope 8
When using as an alignment system using only exposure light, use the on-axis (ON AXrS) without the auxiliary optical system 9.
) Can be used as a microscope. In this case, the first microscope 8 moves to a position where the reticle-side alignment mark 33° 33' arranged in the scribe area 34 around the actual element pattern area 36 of the reticle 1 can be observed. .33'
It is possible to simultaneously observe the wafer-side alignment mark (not shown) and perform alignment in the XYθ directions and the magnification β. In this case, it is necessary to retreat the first microscope 8 from the exposure light beam during exposure.

Here, alignment marks used for each alignment will be explained. In the present invention, it is not necessary to specify the alignment mark, but one such as shown in FIG. 1(d) is used as an example. Even in the case of having various alignment modes like this example, it is desirable for the mark shape to be common from the viewpoint of usability, so in this example, the number (17, 17')
18' ) (32,32' ) (33,33'
) is the mark on the reticle side as shown in Figure 1 (
It is formed like the reticle mark 37 in d). However, in order for the operator or the device to identify which mark is currently being observed, the reticle-side identification mark 38
It is preferable that the marks be different for each of the marks. Also, regarding the alignment mark on the wafer side and the reticle alignment mark 35.35',
It is formed like a wafer mark 39 in FIG. 3(d). Similarly, the wafer side mark also includes an identification mark 40.

◎ [Offset correction for the 633 nm wavelength alignment photodetection system] Since the 633 nm wavelength alignment system uses the auxiliary optical system 9, the read value will have an offset error from the true value if the optical system is set only. When the optical system settings are changed, these offsets must be read and corrected. In this example, the first
Utilizing the fact that detection by the exposure light alignment system of the microscope 8 does not generate a system offset, offset correction of the wavelength 633 nm alignment detection system is performed using this as a reference. This procedure is as follows.

■ Place the first microscope 8 on the reticle side alignment mark 33.
．． 33' is moved to a position where it can be observed, and the reticle alignment mark 35, 35' on the stage-side reference plate 31 is aligned by the alignment system using the exposure light wavelength.

■ Place the first microscope 8 on the reticle side alignment mark 18.
．． Return to the 18' side and read the offset value of the 833 nm wavelength alignment system.

With the above operations, offset reading (correction) is completed.

◎ [Explanation of alignment using light with wavelength 633r+m and control system] FIG. 1(a) shows the state of alignment using light with wavelength 633 nm (He Ne laser). Due to the action of the optical system described above, the imaging element 15 of the first microscope 8
The images of the wafer-side alignment mark MW and the reticle-side alignment mark 18, 18' are simultaneously projected and formed, and the image pickup signal is led to the control circuit 41 for subsequent image processing and error calculation. The signals obtained from the left and right marks are respectively decomposed into two-dimensional directions, including the aforementioned offset value (ΔX - ΔYL) (ΔXR, ΔY
R) and is further output as a drive direction and drive amount.

The drive amount signals in the XYθ directions are sent from the control circuit 41 to the stage 7 to control the stage 7. These detection system and drive system operate in a closed loop, and the amount of error is finally brought within tolerance.

On the other hand, the magnification error amount Δβ is sent to the magnification correction optical system 42. A detailed explanation of the correction is given in Japanese Patent Application No. 174209/1988 entitled "Optical Magnification Correction Apparatus".

By the above operations, after the alignment in the XYθβ directions is completed, immediate exposure can be started. Since the objective mirror 29 is outside the exposure light beam, there is no need to move it away.
The alignment position can be continued to be monitored even during exposure.

The advantages of the alignment system explained above can be summarized as follows.

■ By using multicolor alignment light and various alignment modes, it is possible to compensate for detection defects and precision defects caused by the process, and to achieve stable and highly accurate alignment even when process conditions change.

- Even in non-exposure wavelength alignment, offset correction can be automatically performed on the equipment side due to the existence of exposure wavelength alignment. Furthermore, in alignment using HeNe light, the projected images of the reticle mark and wafer mark can be observed simultaneously, so there is no need to worry about deviations in the reference due to changes over time.

■ Since aberrations are completely corrected for each alignment wavelength, two eyes can be used for any alignment.
Direction detection is possible. Therefore, X
It is possible to detect in the Yθ direction and the magnification β direction, and perfect overlay can be achieved by driving the stage in XYθ.

■ Even if the alignment mark position is on the actual device pattern,
After alignment, there is no relative shift between the reticle and the wafer during exposure, so cycle time can be shortened and accuracy can be improved.

Next, focus detection and driving will be explained.

FIG. 2 shows a conceptual diagram of a TTL focus detection system and a drive system that are provided separately from the alignment detection system described above. Figure 2 (a) is a side view, (b) is a plan view of the reticle part,
(C) is an enlarged view of the portion where the reflected light from the cube is divided into three parts.

The existence of the parallel plate glass 5 and the dichroic mirror 4 provided in the exposure light beam makes it possible to extract the signal light of TTL focus. A focus detection optical system 10 is used to detect the tilt component between the surface of the exposed portion of the wafer 2 and the image plane.
Although three sets of 0 are arranged, only one set is shown in the figure for the sake of simplification. As shown in FIG. 2(b), its arrangement corresponds to the position on the recital side, and the exposure area 1
They are placed equally along the outer periphery of 9 at positions a, b, and c. Here, only the detection signal processing system of section a will be described.

Light with a wavelength of 633 nm emitted from the HeNe laser 01 passes through the illumination lens 102 and enters the half prism 10.
3, the telecentricity correction plate 22, field lens 21, aberration correction plate 107, parallel plate glass 5,
The light is focused on the surface of the wafer 2 via the dichroic mirror 4, the projection lens 3, and the magnification correction optical system 42. The light reflected from the surface of wafer 2 follows the opposite route and reaches half prism 1.
03 and reaches a multi-stage half mirror 104. Figure 2 (C) shows a portion 10 that divides the reflected light from the wafer into three parts.
9 is an enlarged view of FIG. The multi-stage half mirror 104 converts the incident light into three lights! The light is divided into 1IIIR, J, and F, and works to equally distribute the amount of light from each. Multi-stage half mirror 1
After 04, a pinhole plate 105 having a pinhole window centered on each of the optical axes of R, J, and F is inserted, followed by a photoelectric conversion element 106R for each pinhole.

106J and 106F are arranged. Pinhole plate 105
The light that comes out from the lens image plane is light! MJ's pinhole (
J), so that on the optical axis R, the image is formed after the pinhole (R), and on the optical axis F, the image is formed in front of the pinhole CF).

With such a configuration, the photoelectric conversion elements 106R and 106
By comparing the outputs of F, it is possible to determine the direction of deviation of the wafer surface with respect to the image plane, and from the balance between the photoelectric conversion elements 106R and 106F or the maximum output of 106J, it is possible to know whether the image plane and the surface of the sea urchin are matched. The signal photoelectrically converted by the photoelectric conversion element 106 passes through the control circuit 108 and is sent to a, b.
, the tilt correction of the stage 7 is performed at points corresponding to points c.

These series of operations are performed in a closed loop as TTL focusing through the projection lens, so it can sufficiently track not only image plane movement due to atmospheric pressure and outside temperature, but also rapid focus changes caused by exposure light absorption by the lens, etc. It is possible to maintain stable focus at all times.

Furthermore, by employing three-point detection and a tilt mechanism, it is possible to align the surface of the camera with the image plane, making it possible to obtain uniform and good resolution performance over the entire exposure screen.

Furthermore, when exposing repeatedly by relying on the stage 7 and the laser interferometer 130, such as first mask exposure or global alignment exposure, there is a problem that each shot tilt usually causes an alignment error. ) As shown in the stage configuration, a reference plane mirror 13 is mounted on the tilt stage.
This problem can be avoided by setting it to 1.

The alignment optical system and the focus optical system shown in FIG. 1(a) and FIG. 2(a) can be arranged coexisting without interference.

Note that in the above embodiments, it is not necessary to specify the wavelength of the exposure light; for example, the alignment system and focus detection for a projection lens that uses i-line (wavelength 365 nm), excimer laser, etc. Systems can also be constructed in a similar manner.

In the case of an excimer projection lens, the glass materials that can be used for the lens are controlled to two types, so it is difficult to achieve achromatization due to the lens design, and the difference between the exposure wavelength and the alignment wavelength becomes large. Upper chromatic aberration increases. At this time, in the conventional configurations shown in FIGS. 3 and 4, a large take-out mirror 200 or chromatic aberration correction lens 201 is required, and the exposed area becomes vignetted (hatched portion in the figure).
It is unacceptably narrowed because of this. Therefore, in an excimer exposure apparatus, a single-mirror type that covers the entire exposure light beam as in the present invention becomes necessary.

It is also possible to use the alignment detection system shown in FIG. 1 as a focus detection system. In this case, since the detection system for each of the exposure light and the light with a wavelength of 633 nm captures the alignment mark on the image plane with a COD or an image pickup tube, the optimal imaging point can be detected as the contrast of the image.

Furthermore, it is also possible to use these together with the focus-only detection system shown in FIG.

In particular, in order to use the optical system shown in Figure 1 as an alignment system, it is assumed that there is a mark on the wafer side, so in the case of exposure of the first mask, a dedicated focus system as shown in Figure 2 is essential. It is.

[Effects of the Invention] As explained above, according to the present invention, all directions (X, Y, Z,
θ2. Detection system and correction (θ1, θ7 and magnification)
Accordingly, it is possible to realize an exposure apparatus that has a drive system and has an excellent processing speed.

Furthermore, the exposure apparatus according to the present invention can respond to process changes and eliminate errors in the wafer and patterns created thereon.
It is a stable and redundant device that can self-correct even the changes that occur over time, and can always provide stable performance.

[Brief explanation of the drawing]

FIG. 1 is an overall view of an alignment detection system and drive system of an exposure apparatus according to an embodiment of the present invention, and FIG. 2 is an overall view of a focus detection system and drive system of an exposure apparatus according to an embodiment of the present invention. Figure 3.4 is an explanatory diagram of the prior art. 1 reticle, 2. wafer, 3: projection lens, 4: dichroic film, 5: parallel plane glass, 14: objective lens, 20, 107: coma correction plate, 21; field lens, 22: telecentric power correction lens, 25: As-coma correction optical system, 27: Imaging lens, 42: Magnification correction optical system. Patent Applicant Canon Co., Ltd. Agent Patent Attorney Tatsuo Ito Agent Patent Attorney Tetsuya Ito Figure 4

Claims (1)

[Scope of Claims] 1. An exposure apparatus that aligns an original plate and a photosensitive substrate and then projects a pattern drawn on the original plate onto the photosensitive substrate using a projection lens, the exposure apparatus comprising: the projection lens and the original plate; The exposure light flux is reflected and guided to the photosensitive substrate, and the light input from the outside with a wavelength different from the exposure wavelength is transmitted and introduced into the exposure light flux. An exposure apparatus characterized by comprising a spectroscopic means configured to extract light from an exposure light beam. 2. The exposure apparatus according to claim 1, wherein the spectroscopic means is a mirror film of a dichroic mirror. 3. The exposure apparatus according to claim 1 or 2, wherein the original plate is a reticle and the photosensitive substrate is a semiconductor wafer. 4. An exposure device that aligns an original plate and a photosensitive substrate, and then projects a pattern drawn on the original plate onto the photosensitive substrate using a projection lens, the exposure device having an exposure light beam between the projection lens and the original plate. The exposure light flux is reflected and guided to the photosensitive substrate, and the alignment light input from the outside with a wavelength different from the exposure wavelength is transmitted and introduced into the exposure light flux, and the introduced light is introduced into the exposure light flux. alignment light is input to the spectroscopic means, reflected at a predetermined position on the photosensitive substrate, transmitted through a projection lens, and extracted out of the exposure beam by the spectrometer. a first optical system arranged to form an image at a position; and a second optical system located on the opposite side of the original plate from the projection lens and arranged so that the image formation and the pattern on the original plate can be observed simultaneously. An exposure apparatus comprising: an optical system. 5. The exposure apparatus according to claim 4, wherein the spectroscopic means is a mirror film of a dichroic mirror. 6. The first optical system includes an optical system for correcting coma aberration caused by the alignment light having a predetermined non-exposure wavelength passing through the projection lens and the spectroscopic means, and an image plane according to the image height. A field lens corrects the incident angle of the chief ray incident on the lens so that it is in one direction, an optical system corrects the deviation in telecentricity caused by the field lens, and an optical system corrects the astigmatism and coma aberration at the observation position. an as-coma correcting optical system consisting of a plurality of parallel plane glasses placed at an angle with respect to the axis; and an optical system for compensating for axial chromatic aberration and focusing the image on the photosensitive substrate onto the pattern surface of the original plate. An exposure apparatus according to claim 4 or 5, comprising: 7. The exposure apparatus according to claim 4, 5 or 6, wherein the second optical system has aberrations corrected for two wavelengths: an exposure wavelength and a non-exposure wavelength of the alignment light. 8. The exposure apparatus according to claim 4, 5, 6 or 7, wherein the original plate is a reticle and the photosensitive substrate is a semiconductor wafer. 9. The second optical system has an image sensor that receives a projected image on the photosensitive substrate, and can detect coincidence between the image plane of the projection lens and the surface of the photosensitive substrate based on an electric signal obtained from the image sensor. Claim 4, 5, 6, 7 or 8
Exposure device described in Section 2. 10. The second optical system has a photoelectric conversion element, a control circuit that processes a signal obtained from the photoelectric conversion element, and a magnification correction that varies the projection magnification of the projection lens based on the signal from the control circuit. 10. An exposure apparatus according to claim 4, wherein the projection magnification of the projection lens is corrected by an optical system. 11. Claims 4, 5, 6, 7, 8, wherein the original plate is a reticle and the photosensitive substrate is a semiconductor wafer.
The exposure apparatus according to item 9 or 10. 12. An exposure device for aligning an original plate and a photosensitive substrate and then projecting a pattern drawn on the original plate onto the photosensitive substrate using a projection lens, wherein an exposure light beam is provided between the projection lens and the original plate. The exposure light beam is reflected and guided to the photosensitive substrate, and the alignment light input from the outside with a wavelength different from the exposure wavelength is transmitted and introduced into the exposure light beam, and the introduced light is converted into the exposure light beam. A spectroscopic means is taken out from inside, and an alignment light is inputted into the spectroscopic means, reflected at a predetermined position on the photosensitive substrate, transmitted through a projection lens, and further taken out to the outside of the exposure beam by the spectroscopic means. 1. An exposure apparatus comprising: an optical system configured to detect a positional deviation between an image plane formed by a projection lens of a pattern and a surface of a photosensitive substrate. 13. The exposure apparatus according to claim 12, wherein the spectroscopic means is a mirror film of a dichroic mirror.