JPH01289247A - Electronic replication aligner and exposure - Google Patents

Abstract

PURPOSE:To easily check foreign matter and to execute an exposure without lowering the reliability by a method wherein a pattern formation material of a mask is filled into a mask substrate and a photoelectron-emitting material is applied to the mask substrate. CONSTITUTION:A metal 33 is patterned on a transparent substrate 32. Then, an oxide film 34 is grown and applied in such a way that the metal pattern 33 is nearly hidden as a whole; a photoelectron-emitting material 35 is applied to the oxide film 34. Accordingly, an uneven part by the pattern 33 is not formed on a mask 31; foreign matter can be detected easily. By this setup, the foreign matter which adheres during an operation of the mask 31 can be discovered easily and, the reliability of the pattern 33 can be enhanced.

Description

[Detailed Description of the Invention] [Table of Contents] 1. Existing Industrial Fields of Application Prior Art (Figure 3.4) Problems to be Solved by the Invention Examples of Means and Actions for Solving the Problems One Implementation of the Present Invention Example (Figure 1.2) Effects of the invention [Summary] Regarding a photoelectronic transfer device and an exposure method, an electronic transfer device that can easily check for foreign substances and that can perform exposure without reducing reliability with a simple configuration. The object of the present invention is to provide a transfer exposure apparatus and an exposure method, which include a mask in which a pattern to be transferred is formed by a pattern forming material, and receives light from the back side to excite and emit photoelectrons corresponding to the transferred pattern from a photoelectron emitting material; an exposed object to which a pattern is transferred by being irradiated with photoelectrons emitted from the mask; the trajectory of the photoelectrons is controlled by electromagnetic and magnetic fields formed near the exposed object and the mask; In a photoelectronic transfer device that transfers and exposes a pattern on the mask using photoelectrons, the mask is configured such that a pattern forming material is embedded in a mask substrate, and a photoelectron emitting material and a photoelectron emitting material are coated on the mask substrate.

[Industrial application field]

The present invention relates to a photoelectronic transfer exposure apparatus and an exposure method,
Specifically, the present invention relates to a photoelectronic transfer device and an exposure method that can improve the accuracy of transfer by improving the mask structure.

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, 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 resolution, but because the exposure tip is so-called "-brush writing" based on a huge amount of pattern data, it takes time to expose, the throughput is low, and it is not suitable for mass production. Not suitable.

Further, the X-ray exposure method is a proximity exposure method in which a large-scale X-ray light source of 10 to 50 KH is used, and X-rays having a wavelength of 1 to 10 people are used. Therefore, in X-ray exposure, in addition to the light source described above, a combination with an aligner that supports the mask and the wafer and can align them with high precision is required. In this respect, it is similar to the conventional light exposure method, but the light source is large-scale and expensive, the mask constituent material must be considered due to the relationship between the absorption coefficient and the light source wavelength, and furthermore, due to proximity exposure, the wafer The larger the diameter, the more the mask bends and the mask and wafer warp, resulting in a gap change between the mask and the wafer, resulting in blurring. It is difficult to obtain strong X-ray intensity, and the throughput is not very good. It has been proposed to use synchrotron synchrotron radiation, which has high intensity and parallel X-ray beams, as the above-mentioned light source for generating X-rays. It takes time to manufacture and operate, and is difficult to use, so it cannot be said that it is suitable for practical exposure equipment.

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,
Accelerated by the electric and magnetic fields applied between the master wafers,
This is a method of converging and transferring onto a 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. 3(a) and 3(b) are schematic diagrams showing the structure of an example of a conventional photoelectronic transfer bag, and FIG. 4 is a diagram for explaining a conventional photoelectronic transfer exposure method.

In these figures, ■ 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 Si, for example, 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 directs the electron beam emitted from the alignment mark onto a wafer 7
It has a function of scanning over the alignment mark (not shown) on a. 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. 3(b) shows a type of device that irradiates ultraviolet rays 15 from the surface side of a photoelectric mask, in which a parallel magnetic field is applied by magnetic poles 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 between Unibuff a.

Next, photoelectron transfer exposure will be explained using FIG. 4.

As shown in FIG. 4, 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 (in the vertical direction) generated by the converging coil 1, with the photoelectric mask 6 side being negative and the sample 7 side facing each other at right angles to the magnetic field. 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 that hits areas without a pattern (areas where there is no ultraviolet absorber 16) is exposed to ultraviolet rays. 15 hits, and photoelectrons 17 come out from that part as shown by arrow A. The photoelectron 17 that jumped out from a point on the photoelectric mask 6 is
Due to the accelerating voltage applied thereto (given by the power supply 14) and the parallel magnetic field created by the converging coil 1, it moves in the direction of the sample 7 in a spiral pattern, and converges at a certain point again. 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 irradiant ( Hereinafter referred to as resist) is deposited.

However, during transfer, exposure, and light, there are many cases in which electrical discharge occurs between the photoelectric mask and the sample, causing the resist to fly up and become dust. Therefore, in order to prevent the negative effects of dust, for example, a predetermined electrode plate having the same potential as the sample and having a line-shaped opening is installed between the photoelectric mask and the sample, and a first electrode plate is installed to prevent the above-mentioned discharge. We are proposing a device.

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.

[Problem 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 a foreign object lands on the surface, 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, the problem of foreign objects will be eliminated, but the system will be complicated and the movements will be unnatural, which will place a heavy burden on the person designing the device, which is not the best option. .

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 CCD or television camera, but in that case, the system is also large-scale. It ends up.

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

[Means for Solving the Problems] In order to achieve the above object, the electronic transfer exposure apparatus according to the present invention has the following features:
A pattern to be transferred is formed by a pattern forming material, a mask receives light from the back side to excite and emit photoelectrons corresponding to the transfer pattern from the photoelectron emission material, and the pattern is transferred by being irradiated with photoelectrons emitted from the mask. photoelectronic transfer, in which the trajectory of photoelectrons is controlled by an electromagnetic or magnetic field formed near the exposed object and the mask, and the pattern on the mask is transferred onto the exposed object using photoelectrons; In the apparatus, the mask has a structure in which a pattern forming material is embedded in a mask substrate, and a photoelectron emitting material and a photoelectron emitting material are deposited on the mask substrate.

Further, in the method for manufacturing a mask provided to the electronic transfer exposure apparatus, quartz is used as the mask substrate, metal is used as the pattern forming material, and after patterning the quartz substrate with the metal, silicon oxide is applied to the transfer pattern forming area. A mask is manufactured by embedding the metal on a quartz substrate by growing .

On the other hand, in an exposure method using an electronic transfer exposure device, at the stage where the pattern forming material is embedded in the mask substrate, the mask substrate is set in the transfer device, and then the mask is irradiated with light to improve the mask surface. inspecting the mask surface for foreign matter adhesion by observing the reflected light, and then depositing the photoelectron emitting material on the mask substrate and performing transfer and exposure;
In another exposure method, after a photoelectron emitting material is deposited on the mask substrate, the mask is set in a transfer device, the mask is irradiated with light, and the reflected light rays on the mask surface are observed to detect foreign particles on the mask surface. An adhesion test is performed, and then transfer and exposure are performed.

[Effect]

In the present invention, the patterning material of the mask is embedded in the mask substrate, and the photoelectron emitting material is deposited on the mask substrate.

Therefore, unevenness caused by the pattern on the mask is eliminated, and foreign matter can be easily detected.

In the actual exposure process, after the mask substrate is inserted into the exposure equipment, the mask surface is inspected for foreign matter adhesion, and then a photoelectron emitting material is coated and exposed, or photoelectrons are emitted onto the mask substrate. After the material is deposited and set, a foreign matter adhesion test is performed, and then exposure is performed.

Therefore, it is possible to perform inspection during exposure, and it is also easy to deal with the occurrence of foreign matter.

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

FIG. 1 is a diagram showing an embodiment of an electronic transfer exposure apparatus and an exposure method according to the present invention, and particularly shows the structure of a photoelectric mask. In the figure, 31 is a photoelectric mask (hereinafter simply referred to as a mask). The mask 31 is first made as shown in FIG.
As shown in a), a transparent substrate 32 is patterned with a metal 33.

As the substrate 32, for example, quartz or soda glass is used. Further, the metal 33 corresponds to a pattern forming material, and chromium (Cr) is used. The thickness of metal 33 is 500-20
About 00λ is preferable. If the thickness is thinner than this, there is a risk that light will leak when irradiated with light, and if it is too thick, the thickness will form a shadow, making it difficult to obtain pattern accuracy.

Through the above steps, an original plate of the mask 31 has been created. Next, an oxide film 34 made of Sin is grown on the original plate. The oxide film 34 is formed by spin-coating a liquid glass material, for example, and sintering it. Note that the invention is not limited to this, and growth may be performed by a sputtering method using silicon oxide as a target, or by a CVD method if there is no risk of the metal pattern sagging due to heating. You can. These oxide films 34 are made thick enough to cover the entire metal pattern, that is, to cover the metal pattern 33 by about 50 to 500 degrees.

This is because if this thickness is too thick, a correct pattern may not be projected onto the photoelectron emitting material (35, which will be described later) to be deposited thereon. This is due to the fact that the irradiating light is not completely parallel light.

If it is difficult to precisely control the thickness, for example, the oxide film 34 may be formed thickly and then polished to make it flat.

Next, as shown in FIG. 1(b), a photoelectron emitting material 35 is deposited on the oxide film 34 to complete the mask 31.

As the photoelectron emitting material 35, platinum (Pt), S(A)
g), oxidized igon (Ago), etc. are preferable.

Further, the best thickness of the photoelectron emitting material 35 is about 50 people. Note that the photoelectron emitting material 35 may be deposited outside the exposure device, but considering the adhesion of foreign matter such as dust, it is better to deposit the photoelectron emitting material 35 inside the exposure device. The application is already a known technique.

The mask 31 created in this way is used for exposure according to the following procedure.

In the case of the mask 31 to which the photoelectron emitting material 35 is not attached, foreign matter detection is performed by irradiating the mask 31 with light after being installed in the exposure apparatus. This method is illustrated in FIG. It is a well-known technique to irradiate the light 36 obliquely from the mask 31 to help detect foreign matter. This is done automatically within the exposure device.

A detector 37 is installed on the opposite side to which the light 36 is irradiated. Detection is performed by analyzing this detection signal.

Here, the mask 31 determined to be defective is taken out of the apparatus and cleaned again. Even in this case, since a glass-like protective film (ie, oxide film 34) is provided on the mask pattern, there is an advantage that there is no need to worry about the pattern metal. As a result of the inspection, the mask 31 determined to be good is then coated with a photoelectron emitting material 35 and subjected to exposure.

On the other hand, the mask 31 can be used in the same way even if the mask 31 is already coated with the photoelectron emitting material 35 when installed in the exposure apparatus. This corresponds to the photoemissive material 3 deposited on top.
This is because the light 36 is thin, about 50 to 100 people, and about 50% of the light 36 is reflected. Here too, only those with good results are used.

Next, the effect on the prior application example will be considered. First, mask 3
1 has the structure shown in FIG. 1, unevenness caused by the pattern on the mask 31 is eliminated. Therefore, it is possible to easily detect foreign substances like a conventional ultraviolet mask. Moreover, the inspection can also be automatically performed within the exposure apparatus. Furthermore, by having an inspection means in the exposure apparatus, inspection can be performed during exposure, and it becomes easy to deal with the occurrence of foreign matter. In addition, since the pattern is protected, the photoelectron emitting material 35
Peeling and removal of foreign matter can also be performed without worrying about pattern defects.

That is, it is possible to easily check for foreign substances with a simple configuration, and the reliability of exposure can be improved.

In addition, in the apparatus related to the prior application, a mask having a structure in which multiple patterns are formed on one mask was also proposed, but when the present invention is used for this mask, each exposed pattern area can be inspected one by one. This has the advantage that it is not necessary to perform composite exposure. This is because in this case, only good exposure pattern areas can be used. Also, as the exposure continues,
Occasionally, foreign matter may adhere within the exposure apparatus. In preparation for this case, if the pattern is inspected again during the idle time of the apparatus after exposing several sheets, it is possible to carry out exposure with higher reliability than before.

〔effect〕

According to the present invention, it is possible to flatten the surface of a mask used for exposure, and it is possible to easily detect foreign substances attached to the mask when operating it with a simple configuration. As a result, it is possible to expose with a good mask,
Pattern reliability can be improved.

[Brief explanation of the drawing]

1(a) and 1(b) are cross-sectional views showing the structure of a mask showing one embodiment of an electronic transfer exposure apparatus according to the present invention; FIG. 2 is a diagram illustrating inspection of the mask of the above-mentioned embodiment; FIG. 3 is a schematic diagram showing the structure of an example of a conventional photoelectronic transfer device, and FIG. 4 is a diagram illustrating a conventional photoelectronic transfer exposure method.・31...Mask, 32...Substrate, 33...Metal (pattern forming material), 34...
... Oxide film, 35 ... Photoelectron emission material, 36 ... Light, 37 ... Detector.

Claims (4)

[Claims] (1) A pattern to be transferred is formed by a pattern forming material, and a mask receives light from the back side to excite and emit photoelectrons corresponding to the transferred pattern from the photoelectron emitting material; and a mask that receives the photoelectrons emitted from the mask. and an exposed object to which a pattern is transferred by using photoelectrons, the trajectory of photoelectrons is controlled by electromagnetic and magnetic fields formed near the exposed object and the mask, and the pattern on the mask is transferred to the exposed object by photoelectrons. An electronic transfer exposure apparatus characterized in that the mask has a structure in which a pattern forming material is embedded in a mask substrate and a photoelectron emission material is deposited on the mask substrate. (2) Using quartz as the mask substrate and metal as the pattern forming material, after patterning the metal on the quartz substrate, silicon oxide is grown in the transfer pattern forming area to embed the metal on the quartz substrate. 2. A method of manufacturing a mask for use in an electronic transfer exposure apparatus according to claim 1. (3) At the stage where the pattern forming material is embedded in the mask substrate, the mask substrate is set in a transfer device, and then the mask is irradiated with light and the reflected light on the mask surface is observed to identify foreign substances on the mask surface. 2. The exposure method using an electronic transfer exposure apparatus according to claim 1, wherein an adhesion test is performed, and then the photoelectron emitting material is deposited on a mask substrate, transferred, and exposed. (4) After depositing the photoelectron emitting material on the mask substrate, set the mask in a transfer device, irradiate the mask with light, and observe the reflected light on the mask surface to inspect the adhesion of foreign matter on the mask surface. 2. An exposure method using an electronic transfer exposure apparatus according to claim 1, further comprising performing transfer and exposure.