JPH01289248A - Photoelectronic replication apparatus - Google Patents

Abstract

PURPOSE:To easily check foreign matter and to execute an exposure without lowering the reliability by means of a simple constitution by a method wherein a beam-shape detection means is arranged in a replication exposure region part and a beam shape of a photo-electron is detected. CONSTITUTION:An electrode plate 42 is arranged in a replication exposure region part between a mask 34 and a wafer 31; when an electron beam 41 strikes the electrode plate 42, an electric current flows; this electric current is converted into an electric signal and A/D-converted by means of an A/D converter 43. A microcomputer 44 detects a shape of the electron mean 41 on the basis of an output from the A/D converter 43 and a shifted distance (d) of the electrode plate 42, and recognizes the existence of foreign matter 33 which has adhered to the mask 34 from a disorder of a beam pattern. By this setup, the foreign matter can be detected by means of a simple constitution and easily; the reliability of a pattern can be enhanced.

Description

[Detailed Description of the Invention] [Table of Contents] Overview Industrial Application Fields Prior Art (Figure 6.7) Problems to be Solved by the Invention Examples of Means and Actions for Solving the Problems The Invention Principles (1st Figure) First embodiment of the present invention (Figures 2 to 4) Second embodiment of the present invention
(Fig. 5) Effects of the invention [Summary] To provide a photoelectronic transfer device that can easily check for foreign substances and that can perform exposure without reducing authenticity with a simple configuration. A mask that excites and emits photoelectrons in a pattern by irradiation with light, and an exposed object to which the pattern is transferred by being irradiated with the photoelectrons emitted from the mask, and the exposed object and a photoelectronic transfer device that controls the trajectory of photoelectrons by an electromagnetic or magnetic field formed near the mask, and transfers and exposes the pattern on the mask onto the object to be exposed using photoelectrons. It is configured by providing a beam shape detection means for detecting the shape, and a foreign matter detection means for detecting foreign matter attached to the mask based on the output of the beam shape detection means.

[Industrial Application Field] The present invention relates to a photoelectronic transfer device, and more particularly to a photoelectronic transfer device that can improve the reliability of transfer.

Ultraviolet exposure methods have been used as a lithography technique for a long time.Since then, ultraviolet exposure methods have been repeatedly improved to make patterns finer.
It has been pointed out that there is a limit to miniaturization beyond the limit of about 1,000 people, and techniques such as electron beam exposure, X-ray exposure, and photoelectron transfer exposure are being considered.

Hereinafter, the electron beam exposure method, the X-ray exposure method, and the photoelectron transfer exposure method will be specifically explained.

In the electron beam exposure method, an electron beam with a dotted or rectangular cross section is deflected, irradiated onto the wafer without changing its position, and a stage is moved to draw a fine pattern on the wafer. . Therefore, the electron source,
In addition to a column system that converges, shapes, and deflects the electron beam, and a stage system that supports the wafer and changes the exposure position, a control system that controls these is required. This method can hope to improve the resolution, but because it uses so-called "-brush writing" exposure based on a huge amount of pattern data, the exposure takes time, the throughput is low, and it is not suitable for mass production. Not suitable.

The X-ray exposure method is, for example, a proximity exposure method in which a large-scale X-ray light source of 10 to 50 mm is used and X-rays having a wavelength of 1 to 10 mm are used. Therefore, in X-ray exposure, in addition to the above-mentioned light source, a combination of a mask and an aligner that supports the wafer and can align both with high precision is required. In this respect, it is similar to the conventional light exposure method, but the light source is large and expensive;
Due to the relationship between the absorption coefficient and the light source wavelength, consideration must be given to the mask constituent materials.Furthermore, due to proximity exposure, the larger the wafer diameter, the more the mask will bend and the mask and wafer will warp, resulting in mask-wafer distortion. There is a problem in that the gap between images changes, resulting in blurring. It is difficult to obtain strong X-ray intensity, and the throughput is not very good. The X-ray beam is strong and parallel. It has been proposed to use synchrotron synchrotron radiation as the light source for X-ray generation, but the equipment would be large-scale, the manufacturing and operation of the equipment would be extremely expensive, and it would be difficult to use. It cannot be said that the device is suitable for practical use.

As an exposure method that takes advantage of both the high throughput of the transfer method and the high resolution of the electron beam exposure method, there is a transfer exposure method using photoelectrons. This exposure method involves patterning a photoelectron-emitting material and a non-emitting material on a mask.
Photoelectrons generated by shining light on the mask,
This is a method of accelerating and converging the electric, magnetic, and magnetic fields applied between the master wafers and transferring them onto the wafer.

In such photoelectronic transfer exposure methods, foreign matter adhering to the mask surface has a serious effect on the exposure results. Therefore, it is important to create an exposure device that does not allow foreign matter to adhere to the exposure mask, or to take measures to prevent foreign matter from being transferred even if it adheres, or to promptly detect and deal with foreign matter if it does adhere.

[Conventional technology]

FIGS. 6(a) and 6(b) are schematic diagrams showing the structure of an example of a conventional photoelectronic transfer device, and FIG. 7 is a diagram for explaining a conventional photoelectronic transfer exposure method.

In these figures, 1 is a focusing coil called a Helmholtz coil, 2 is an XY stage, 3 is a mask stage, 4 is an exhaust port, 5 is a flat electrode, 6 is a photoelectric mask, 7a is a wafer made of, for example, St. 7b is an electron beam sensitizer; 7 is a sample; the sample 7 consists of a wafer 7a and an electron ray sensitizer 7b, and is moved by the XY stage 2; 8 is a deflection coil.

9 is an ultraviolet lamp, 10 is a window, and the deflection coil 8 has a function of scanning an electron beam emitted from the alignment mark onto, for example, an alignment mark (not shown) on the wafer 7a. 11 is a stand, 12 is a magnetic pole, 13 is a chamber, 14 is a power source, 15 is an ultraviolet ray, 16b is an ultraviolet absorber, and the ultraviolet absorber 16b is made of Cr.

17 is a photoelectron, 18 is a mask substrate made of a transparent quartz plate, and 19 is a photoelectron emitting material, which is made of a substance that can easily excite and emit photoelectrons by ultraviolet rays 15.

Note that here, the flat plate electrode 5 is a photoelectric mask 6-unibuff a
It functions as an electrode for defining an equipotential surface formed therebetween, and also functions as a stand on which a detector (not shown) for detecting reflected electrons from the wafer 7a is mounted. FIG. 6(b) shows ultraviolet light 15 from the surface side of the photoelectric mask 6.
This is a type of device that irradiates the magnetic field, and here a parallel magnetic field is applied by the magnetic pole 12. Further, a photoelectron emitting material 19 is patterned on the photoelectric mask 6, and a backscattered electron detector (not shown) is formed on the flat plate electrode 5.

This detector detects the reflected electrons generated when the photoelectrons 17 emitted from the alignment mark on the photoelectric mask 6 hit the alignment mark on the wafer 7a.
-Align the positions of the sea urchin buffs a.

Next, photoelectron transfer exposure will be explained using FIG. 7.

As shown in FIG. 7, a photoelectric mask 6 and a sample 7 are placed facing each other in parallel at right angles to the magnetic field in a parallel magnetic field (vertical direction) generated by the converging coil 1, with the photoelectric mask 6 side being negative and the sample 7 A potential is applied so that the side is positive. The photoelectric mask 6 is made by covering a pattern to be transferred consisting of an ultraviolet absorber 16b and a film of a photoelectron emitting material 19 that emits photoelectrons when irradiated with ultraviolet rays 15.

Then, an ultraviolet lamp 9 that emits ultraviolet rays 15 is installed on the mask substrate 18, and when the ultraviolet rays 15 are irradiated onto the photoelectric mask 6, the photoelectron emitting material 19 corresponding to the areas where there is no pattern (the area where there is no ultraviolet absorber 16) is exposed to the ultraviolet rays. 15 hits, and photoelectrons 17 come out from that part as shown by arrow A. In the case of the device shown in FIG. 6(b), light is emitted only from the photoelectron emitting material 16a. The photoelectrons 17 ejected from one point on the photoelectric mask 6 are accelerated by the accelerating voltage (power supply 14
) and the parallel magnetic field created by the converging coil 1, it moves in a spiral direction toward the sample 7 and converges at a certain point. In other words, focus.

Here, in the apparatus shown above, the photoelectric mask and the sample face each other as electrodes, a high voltage for accelerating electrons is usually applied to the photoelectric mask, and an electron beam sensitizer (hereinafter referred to as , resist) is deposited. During transfer and exposure, electrical discharge occurs between the photoelectric mask and the sample, often causing the resist to fly up and become dust.

Therefore, as a means to solve the above-mentioned discharge problem, the applicant of the present invention has previously proposed a first photoelectronic transfer device as shown in FIGS. 8(a) and 8(b). Showa 63
(See patent application filed March 31, 2013).

In these figures, the same reference numerals as in FIGS. 6 and 7 indicate the same or corresponding parts. 14a is a power source, 21 is an electrode plate, and 22 is, for example, a width d2 of about 1 mm and a length of 3 cm.
It is a slit-shaped opening that is more than a certain size.

Note that here, the acceleration voltage for accelerating the photoelectrons 17 is applied to the photoelectric mask 6 and the electrode plate 2 having a slit-shaped opening 22.
1, and no voltage is applied between the electrode 21 and the wafer 7a, and the same potential is maintained between the electrode 21 and the wafer 7a.

Next, the principle of operation will be briefly explained.

The ultraviolet light 15 from the ultraviolet lamp 9 is formed into an elongated beam (its width d1 is smaller than the width d of the slit-like opening 22, dl<d2), reaches the photoelectric mask 6, and excites photoelectrons 17. ,discharge.

The photoelectrons 17 are accelerated by an accelerating voltage applied between the photoelectric mask 6 and the electrode plate 21, and only the photoelectrons 17 that have passed through the slit-shaped opening 22 proceed toward the wafer 7a, thereby transferring the mask pattern onto the wafer 7a. do. photoelectric mask 6,
By moving both wafers a in parallel and in the same direction, the pattern placed on the photoelectric mask 6 can be transferred onto the wafer 7a at a ratio of 1:1.

In this device, the photoelectrons 17 are shielded by the electrode plate 21 except for at least the slit-shaped opening 22, so there is almost no discharge to the sample 7, especially the wafer 7a, and there is almost no possibility of damage.

There is an advantage.

Separately, there is also a second device that uses multiple masks with the same transfer pattern and performs overlapping exposure to ensure reliability of the exposed pattern even if foreign matter such as dust adheres to it. We are developing.

[Problems to be Solved by the Invention] However, it has been found that improvement is desirable in the following points even in the first and second devices according to the above-mentioned prior application.

That is, the first device has a drawback in that when foreign matter adheres, its shadow is transferred. Furthermore, the second device has the disadvantage that it is vulnerable to the generation of dust due to discharge. On the other hand, if both the first and second devices are combined, there will be no problem with foreign objects (but the system will be complicated and the movement will be unnatural, which will place a heavy burden on the person designing the device, so this is not the best option). I can not say.

Furthermore, as another system, we have developed a device that irradiates a photoelectric mask with light and magnifies the image using a magnetic field and observes it with a COD or TV camera, but in that case, the system would also be large-scale. It ends up.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a photoelectronic transfer device that can easily check for foreign substances and can perform exposure with a simple configuration without reducing reliability.

[Means to solve the problem]

In order to achieve the above object, the photoelectronic transfer device according to the present invention includes a mask that excites and emits photoelectrons in a pattern by irradiation with light, and an exposed object to which a pattern is transferred by being irradiated with photoelectrons emitted from the mask. In a photoelectronic transfer device that controls the trajectory of photoelectrons by electromagnetic and magnetic fields formed near the object to be exposed and the mask, and transfers and exposes the pattern on the mask to the object to be exposed by photoelectrons. A beam shape detection means is provided in the region and detects the beam shape of photoelectrons, and a foreign matter detection means is provided to detect foreign matter attached to the mask based on the output of the beam shape detection means.

[Effect]

In the present invention, a beam shape detection means is disposed in the transfer exposure area, and the beam shape of photoelectrons is detected. At this time, if foreign matter adheres to the mask, the emitted beam in a certain range from that part will be distorted, and the transferred pattern will also become blurred.

Therefore, by observing the shape, particularly the sharpness, of the emitted beam with the foreign object detection means, the presence of foreign objects can be easily and clearly identified with a simple configuration.

〔Example〕

Hereinafter, the present invention will be explained based on the drawings.

The present invention will first be described in detail with reference to FIG.

There are broadly two types of pattern defects on a photoelectric mask (hereinafter simply referred to as a mask). Defects are caused by buttering errors or foreign matter adhering to the mask during buttering, and defects are caused by foreign matter adhering to the mask surface after the mask is completed. For example, in Figure 1 (a
), when the shadow 33x of the foreign object 33 is projected onto a certain part of the exposed portion 32 of the wafer 31, if it is the foreign object 33 during buttering as in the former case, the first
As shown in Figure (b), the mask 34 is patterned together with a pattern forming material 36 made of metal that is patterned onto the substrate 35, and then the photoelectron emitting material 37 is deposited thereon. After 31 exposures,
As shown in FIG. 1(c), the shadow 33x of the foreign object 33 appears as it is in a clear pattern.

On the other hand, in the latter case where the substrate 35 is attached on top of the photoelectron emitting material 37 as shown in FIG. 1(d), the portion of the photoelectron emitting material 37 is hidden by the substrate 35, and Since the electric field in the vicinity of the substrate 35 is disturbed, the transferred pattern becomes thick (distorted) so as to surround the shadow 35χ of the foreign object 33, as shown in FIG. 1(e). Since this appears as a fluctuation in the electron orbit, it is possible to observe the presence or absence of foreign matter by measuring the electron profile in that part of the orbit.

The present invention is based on the above principle, and a first embodiment thereof will now be described with reference to FIGS. 2 to 4. In Gorera's episode,
The same reference numerals as those shown in FIG. 1 indicate the same or corresponding parts. An electrode plate (beam shape detection means) 42 is disposed in the transfer exposure area between the mask 34 and the wafer 31 (meaning the area where the electron beam 41 in the figure exists). It has a structure that allows it to move in the left and right direction (direction across the cross section of the electron beam 41). In this case, assuming that the center of the wafer 31 is 0, the electrode plate 42 can be moved until the distance j4d from the center 0 reaches a predetermined value from zero. Note that the number of electrode plates 42 affects the resolution of the electron beam 41, so it is better to have a larger number.For example, it is preferable to provide a plurality of electrode plates 42 independently and measure them using the Knifezi method. Further, the electrode plate 42 is arranged at a photoelectron focusing position determined by transfer conditions such as the applied electric field, magnetic field, and the distance between the mask 34 and the wafer 31.

When the electron beam 41 hits the electrode plate 42, a current flows, and this current is converted into a voltage signal by an A/D converter 43, A/D converted, and inputted to a microcomputer 44 including a CPU. microcomputer 4
4 detects the shape of the electron beam 41 based on the output from the A/D converter 43 and the moving distance d of the electrode plate 42, and detects the foreign matter 33 attached to the mask 34 from the disturbance of the beam pattern.
identify the existence of The A/D converter 43 and the microcomputer 44 constitute foreign object detection means 45. Note that 46 is an XY stage.

Next, the operation will be explained. First, the disturbance of the electron beam 41 due to the adhesion of the foreign matter 33 will be explained based on FIG. 2.3.

FIG. 2 shows a case where no foreign matter 33 is attached to the mask 34. In photoelectron transfer, the emitted electrons are transferred to the mask 3.
Since the electron beam 41 spreads to about 100 μm between the wafer 4 and the wafer 31, the disturbance of the electron beam 41 caused by the adhesion of foreign 1yJ33 is measured at the portion where the photoelectrons are focused, using the so-called Knifezi method.

Now, part B in FIG. 2(a) is shown as in FIG. 2(b), and no foreign matter 33 is attached to the lower surface of the mask 34. Therefore, the electric field is not disturbed (the equipotential lines are not disturbed), and the emitted beam (electron beam 41) from the microscopic photoelectron emitting portion on the mask 34 heads toward the wafer 31 in a normal pattern.

Therefore, the electron beam 41 detected by the electrode plate 42
The relationship between the distance d and the distance d is shown in FIG. 2(C).

On the other hand, FIG. 3 shows a case where a foreign object 33 adheres to the mask 34, and due to the appearance of the foreign object 33, FIG.
), the pattern of equipotential lines is disturbed and the electron beam 41 spreads laterally compared to the normal state. Therefore, the relationship between the distance d and the distance d of the electron beam 41 detected by the electrode plate 42 is as shown in FIG.
1 spreads in the horizontal direction until it reaches a distance (the normal spread is a distance a). For example, when a foreign matter 33 of about 100 mL adheres to the mask 34, the blurring range is about 2 to 5 μm, although it depends on the size, height, and material of the foreign matter 33.

Next, changes in the signal pattern based on differences in the locations where the foreign matter 33 is attached will be explained. The foreign matter 33 is an electron beam 4 that crosses the electrode plate 42 every certain fixed exposure time or certain number of exposures.
1 is measured, and the presence or absence of adhesion is determined from changes in the signal pattern based on the measurement results. Further, since the inspection cannot be carried out at once, for example, the inspection is carried out by emitting photoelectrons from a certain line of the mask 34, and then the entire mask 34 is sequentially scanned with these photoelectrons to carry out the entire inspection.

As a preferable example, a light source for positioning or the like may be used to scan and continuously inspect minute areas one by one, and this improves detection accuracy. this is,
This is because the illuminance of the light increases, making it easier to detect the signal. Moreover, as a more preferable example, if the second harmonic of an Ar laser is used as the light source, the photoelectron emission ability will be increased, so that the inspection ability can be further improved.

As shown in FIG. 4(a), if a foreign object 33 is attached to the pattern forming material 36 made of Cr, no signal can be detected even if it is scanned, but the foreign object 33 may affect the patterning of the transfer. Since it does not affect the image, there is no problem (this part appears black). On the other hand, if a foreign object 33 is attached to the photoelectron emitting material 37 as shown in FIG. 4(b), the image should originally appear white, but the signal level of the portion where the foreign object 33 is attached becomes low. In this case, since the manner of decrease is broad, the foreign object 33 and the pattern can be identified by looking at the slope of decrease. Further, as shown in FIG.
When the foreign matter 33 is placed on the foreign object 33, the signal decreases clearly at the pattern portion (the bulging portion of the pattern) and broadly at the portion where the foreign matter 33 is attached. Therefore, the foreign matter 33 can be inspected while accurately distinguishing between the bulge in the pattern and the foreign matter 33.

The above-described inspection for adhesion of foreign matter 33 is automatically performed within the exposure apparatus, and masks 34 determined to be defective as a result are taken out of the apparatus and cleaned. In this embodiment, the disturbance of photoelectrons can be detected by deflection by an electric field or a magnetic field onto the electrode plate 42 to be detected, so the inspection time for inspection of foreign matter adhesion is sufficiently fast, and the hour wheel configuration makes it easy to detect foreign matter. can be performed, and the reliability of transcription can be improved.

Next, FIG. 5 is a diagram showing a second embodiment of the present invention, and this second embodiment is an example in which the present invention is applied to the first apparatus according to the earlier application mentioned above. For convenience of explanation, the same components as those shown in FIG. 8 are given the same numbers and their explanations will be omitted. In FIG. 5, a small second electrode is placed on the electrode plate 21.
An electrode plate (beam shape detection means) 51 is placed thereon, and the second electrode plate 51 is structured to be movable on the electrode plate 21 in the horizontal direction in the figure. In addition, the electrode plate 21 and the power source 1
A current measuring device 52 is inserted between the second
The electron beam crossing the electrode plate 51 can be detected as a current value by a current measuring device 52. The current measuring device 52 is connected to the A/D converter 43, and the subsequent configuration is the same as that of the first embodiment.

In the above configuration, the photoelectrons emitted from the photoelectric mask 6 are once focused on the aperture 22, and then move onto the wafer 7a while performing a circular motion between the aperture 22, to which a magnetic field is applied but not an electric field, and the unihaf a. to refocus. If there is a foreign object, the photoelectrons in that area will not be able to be focused on the linear aperture 22, so this disturbance in focusing can be automatically corrected by moving the second electrode plate 51 as in the first embodiment. can be detected. As a result, the same effects as in the first embodiment can be obtained.

Here, the arrangement position of the second electrode plate 51 is not limited to the upper surface of the electrode plate 21, but may be placed below the opening 22. In such a case, there is no particular need to vary the electric field or magnetic field.

Note that in each of the above embodiments, an electrode plate serving as a beam shape detection means is disposed between the mask and the wafer, but the present invention is not limited to this. Any part where photoelectrons are focused may be used.
For example, it may be placed below the XY stage and the disturbance of the electron beam may be observed from there.

In addition, the beam shape detection means is not an electrode plate, but, for example, a PI
N photodiodes may also be used.

Furthermore, in each of the above embodiments, disturbances in the electron beam are detected by moving the beam shape detection means, but on the contrary, the beam shape detection means is fixed and the electric and magnetic fields are changed to detect the electron beam. Disturbances in the beam may also be detected.

〔effect〕

According to the present invention, it is possible to easily detect foreign substances adhering to a mask in an exposure apparatus using a clockwise configuration, it is easy to manage the mask during exposure, and the reliability of the pattern after exposure is improved. be able to.

As a result, the quality of the patterned product can be improved.

[Brief explanation of the drawing]

FIG. 1 is a diagram for explaining the present invention in detail, FIGS. 2 to 4 are diagrams showing a first embodiment of the photoelectronic transfer device according to the present invention, and FIG. 2 shows a case in which the foreign matter does not adhere. 3 is a diagram showing the case where the foreign matter adheres, FIG. 4 is a diagram for explaining the disturbance of the signal pattern due to another aspect of the foreign matter, and FIG. 5 is a photoelectronic transfer device according to the present invention. 6 is a schematic diagram showing the structure of an example of a conventional photoelectronic transfer device, FIG. 7 is a diagram illustrating a conventional photoelectronic transfer exposure method, and FIG. 8 is a diagram illustrating a conventional photoelectronic transfer exposure method. 1 is a schematic configuration diagram showing a first photoelectronic transfer device according to the present application. 31...Wafer, 32...Exposed portion, 33...Foreign matter, 34...Mask, 35...Group (reverse, 36. ... Pattern forming material, 37 ... Photoelectron emission material, 41 ... Electron beam, 42 ... Electrode plate (beam shape detection means), 45
... Foreign object detection means, 51 ... Second electrode (beam shape detection means),
52... Current measuring device. 36: Pattern-forming material Figure 3 λ Gobo Shokue Reijou Sun Moon Fang 1 lol'i 已 f Daiji's fT Σ kudzu month lead diagram Figure 4 Stay 4 Sun Moon Fang 2 Ga, δE M+"J l ice 7 figure 5 Taro body wash 1J's Suf whisper → p Yun 1 yen ward tt ton Hanbo W
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Claims (1)

[Scope of Claims] A mask that excites and emits photoelectrons in a pattern by irradiation with light, and an exposed object to which the pattern is transferred by being irradiated with the photoelectrons emitted from the mask, the exposed object In a photoelectronic transfer device that controls the trajectory of photoelectrons by an electromagnetic or magnetic field formed near an object and the mask, and transfers and exposes a pattern on the mask to the object to be exposed using photoelectrons, A photoelectronic transfer apparatus comprising: a beam shape detection means for detecting a beam shape; and a foreign matter detection means for detecting foreign matter attached to the mask based on the output of the beam shape detection means.