JPH01168024A - Photoelectron transfer mask and manufacture thereof - Google Patents

Abstract

PURPOSE:To continuously discharge many photoelectrons by irradiating a light output from a general light source without using a special light source by so forming an electroconductive film covering a substrate, and a photoelectric film made of cesium antimonide as to draw a predetermined pattern on the electroconductive film. CONSTITUTION:A substrate 21 is covered with a metal film 22. Then, an Sb film 23a is so formed as to draw a predetermined pattern on the film 22. Then, the substrate 21 is heated by a heater 24 or the like, and Cs atoms 23b are deposited in vacuum while heating the substrate 21. The atoms 23b are deposited on and reacted with the film 23a to form a CsSb film 23 of a predetermined pattern. The Cs atoms 23b are deposited on and reacted with the Sb films 23a while heating the substrate 21, thereby forming a CsSb film 23 of a predetermined pattern. Thus, the film 23 having the predetermined pattern can be formed on the substrate 21.

Description

[Detailed Description of the Invention] [Summary] A reflective photoelectronic transfer mask that irradiates a photoelectric film with light from a light source directly or by reflecting it with a reflecting mirror, and emits photoelectrons from the photoelectric film, and the photoelectronic transfer mask. The purpose of this method is to continuously emit a large number of photoelectrons by irradiating light output from a commonly available light source without using a special light source. It is constructed to include a deposited electrically conductive film and a photoelectric film made of cesium antimonide formed in a predetermined pattern on the electrically conductive film.

[Industrial application field]

The present invention relates to a photoelectronic transfer mask and a method for manufacturing the same, and in particular to a reflective photoelectronic transfer mask in which light from a light source is irradiated directly or reflected by a reflecting mirror onto a photoelectric film, and photoelectrons are emitted from the photoelectric film, and the same. The present invention relates to a method of manufacturing a photoelectronic transfer mask.

[Conventional technology]

In recent years, integrated circuits have become smaller and more highly integrated, and ultra-LS
Microfabrication processes are becoming important in the production of I. 1 of this microfabrication technology (lithography technology)
One example is a technique for transferring fine patterns onto wafers and the like.

Conventionally, an ultraviolet exposure method has been widely used as a technique for transferring such fine patterns. This ultraviolet exposure method has been improved in various ways, and recently, for example, a 5:1 or 10:l
Reduction projection exposure is also performed. However, 4
Even if a fine pattern is transferred onto a wafer, etc. by reduction projection using light with a wavelength of 1,000 people, the finer the pattern, the greater the effect of blurring of the transferred image due to diffraction, interference, etc., and the resolution may be reduced to 0. It is actually extremely difficult to make the thickness .8 μm or more.

On the other hand, in recent years, techniques such as electron beam exposure, X-ray exposure, and photoelectronic image transfer have been proposed and put into practical use in order to improve resolution.

In the electron beam exposure method, a beam having a dotted or rectangular cross section is deflected, the beam is irradiated onto a wafer without changing its position, and a fine pattern is drawn on the wafer in conjunction with a stage.

However, this method requires various devices such as an electron beam generation source, a column for converging, shaping and deflecting the electron beam, a stage for supporting the wafer and changing the exposure position, and
A control system is required to control these devices. That is,
Although it is possible to achieve improved resolution with the electron beam exposure method, it is difficult to perform sequential exposure according to a large amount of data.
It requires a long exposure time and has low throughput. Therefore, there is a problem that the electron beam exposure method is not suitable for mass production.

In addition, the X-ray exposure method uses, for example, X-rays with a wavelength of 1 to 10 people output from a large-scale X-ray light source of about IOK to 50 KW.
This is a proximity exposure method that uses lines. Therefore, in the X-ray exposure method, in addition to the above-mentioned X-ray light source,
It requires an aligner device that can support the mask and wafer and align them with high precision, and is similar to conventional ultraviolet exposure methods. However, as mentioned above, the X-ray light source is large-scale and expensive, the material of the mask must be carefully selected due to the relationship between the absorption coefficient and the light source wavelength, and since the proximity exposure method is used, the wafer diameter The larger the mask and wafer warpage, the more problems arise such as blur caused by gap fluctuations between the master wafers. Although it has been proposed to use synchrotron radiation as the above-mentioned light source for generating X-rays, it is difficult to use it efficiently as the equipment is large-scale, and it cannot be said that it is suitable for mass production.

Therefore, as an exposure method that has both the high throughput of ultraviolet exposure and the high resolution of electron beam exposure, a transfer method using a same-size pattern using a photoelectronic transfer mask has been proposed. According to this photoelectronic image transfer method, similar to the ultraviolet exposure method, high-throughput exposure can be performed in which a patterned mask can be transferred all at once.

FIG. 4 is a sectional view schematically showing an example of a conventional photoelectronic transfer mask.

The photoelectronic transfer mask shown in FIG. 4 is a reflective type mask, and this conventional photoelectronic transfer mask is made of a metal (for example, gold: A (Au) film 122 is provided. This metal film 122 forms a predetermined pattern on the GaAs substrate 121. Then, the metal film 122
A Cs film 123 is deposited on the GaAs substrate 121 which has pattern defects. As a result, G a A s
A photoelectric film formed of -Cs is arranged to draw a predetermined pattern. In this way, the photoelectron transfer mask shown in FIG. 4 uses GaAs-Cs as a photoelectric film that emits photoelectrons.
is used.

In addition to the above-mentioned GaAs-Cs, for example, cesium iodide (CsI) and silver-oxygen monocesium (Ag-0-Cs) are known as photoelectric films.

[Problems that the invention attempts to solve]

As mentioned above, as the photoelectric film of the conventional photoelectronic transfer mask, GaAs-Cs, Cs 1. Ag-0-Cs etc. are used.

First, GaAs-C was used as the photoelectric film of the photoelectron transfer mask.
The problems when using s will be explained.

200aAs-Cs is mainly used for reflective masks, and the substrate is made of GaAs.
A photoelectronic transfer mask is formed by forming a Cs layer on the surface of a substrate to a thickness of several atoms.

This GaAs-Cs photoelectric film is 3.500 to 7.0
It has the advantage of being able to be excited by visible light with a wavelength of 0.000 nm, and also being able to stably and continuously emit photoelectrons in this wavelength range.

However, when GaAs-Cs is used as a photoelectric film, it is possible to stably and continuously emit a large amount of photoelectrons in the visible light wavelength region at the initial stage of light irradiation; The time it takes to do so is extremely short (
After a short period of time (for example, several minutes), the number of emitted photoelectrons will decrease dramatically. This is because other molecules are attached to the Cs atomic layer on the GaAs surface, or other molecules are substituted for Cs atoms, so the effect of promoting photoelectron emission by Cs atoms decreases, and the GaAs is excited. This is because the amount of work required to emit photoelectrons increases. and,
It is difficult to purify the GaAs surface, that is, to eliminate other molecules attached to the GaAs surface and to regenerate the Cs atomic layer.
There is a problem in that this purification work must be performed frequently.

Next, problems when using CsI as a photoelectric film of a photoelectronic transfer mask will be explained. CsI has the advantage of being relatively stable even in the atmosphere and being easy to handle. However, this Csl has a basic absorption edge at about 6 eV, and light with higher energy (for example, 2,0
Photoelectrons cannot be emitted unless excited by ultraviolet light (with a wavelength of 0.00 nm), and it is necessary to use a special light source such as a low-pressure mercury lamp to excite the photoelectric film of Csl.

By the way, since light from a low-pressure mercury lamp is absorbed in the air, the optical system must be constructed in a vacuum. Furthermore, although Csl is a vapor deposited film, pattern defects are likely to occur due to uneven vapor deposition.

Furthermore, when photoelectrons are continuously emitted by light irradiation, they deteriorate and the photoelectron emission efficiency decreases, but when the photoelectron emission efficiency decreases, the photoelectric film made of Csl is regenerated to improve the photoelectron emission efficiency. It is not easy to increase. As described above, when Csl is used as a photoelectric film, there are various problems.

The present applicant previously proposed the use of Ag-0-Cs as a photoelectric film for a photoelectronic transfer mask. This Ag
A photoelectronic transfer mask using -0-Cs as a photoelectric film has high photoelectron termination efficiency using a light source in the visible wavelength range, and can be used in both transmission and reflection types. A photoelectronic transfer mask that does not require frequent cleaning operations can be obtained.

However, it is difficult to stably manufacture a photoelectronic transfer mask using Ag-0-Cs as the photoelectric film, and the photoelectric film made of Ag-0-Cs has a short lifespan. Therefore, when Ag-0-Cs is used as the photoelectric film, there is a problem that it is difficult to stably supply a photoelectron transfer mask with high photoelectron generation efficiency.

In view of the various problems of the conventional photoelectronic transfer masks described above, the present invention forms a photoelectric film made of cesium antimonide in a predetermined pattern on an electrically conductive film adhered to a substrate surface. By doing so, the purpose is to continuously emit a large number of photoelectrons by irradiating light output from a generally available light source without using a special light source.

The present invention also provides the following methods: depositing an electrically conductive film on a substrate; forming an antimony film in a predetermined pattern on the electrically conductive film;
A photoelectronic transfer mask that allows cesium to be vapor-deposited and reacted on an antimony film with a predetermined pattern in a vacuum, thereby forming a cesium antimonide film with a predetermined pattern on an electrically conductive film and continuously emitting stable photoelectrons. The purpose is to easily manufacture.

[Means for Solving the Problems] According to the first aspect of the present invention, a substrate, an electrically conductive film deposited on the surface of the substrate, and a method for drawing a predetermined pattern on the electrically conductive film are provided. A photoelectronic transfer mask is provided, which includes a photoelectric film made of cesium antimonide formed in a photoelectronic transfer mask.

According to a second aspect of the present invention, an electrically conductive film is deposited on a substrate, an antimony film of a predetermined pattern is formed on the electrically conductive film, and the antimony film of the predetermined pattern is coated in a vacuum. A method for manufacturing a photoelectronic transfer mask is provided, which comprises depositing and reacting cesium to form a cesium antimonide film having a predetermined pattern on the electrically conductive film.

[For production]

According to the photoelectronic transfer mask of the first form of the present invention having the above-described configuration, the electrically conductive film is adhered to the substrate surface,
A photoelectric film made of cesium antimonide is formed on this electrically conductive film in a predetermined pattern.

According to the method for manufacturing a photoelectronic transfer mask according to the second aspect of the present invention, first, an electrically conductive film is deposited on a substrate;
A cesium antimonide film having a predetermined pattern is formed on the deposited electrically conductive film. Thereby, a photoelectron transfer mask that can continuously emit stable photoelectrons can be easily manufactured.

(Example) Hereinafter, an example of a photoelectronic transfer mask and a method for manufacturing the same according to the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view schematically showing an embodiment of a photoelectronic transfer mask according to the present invention.

As shown in FIG. 1, in the photoelectronic transfer mask 2, a metal film 22 is deposited on the surface of a substrate 21, and a CsSb film 23 is formed on the metal film 22 in a predetermined pattern. That is, the photoelectric film is formed as a CsSb film 23, and a predetermined pattern of this CsSb film 23 is transferred onto a sample to be exposed, such as a wafer. Here, as the material used for the substrate 21, for example, GaAs
A semiconductor, a silicon (Si) semiconductor, or the like is used, but since the conditions for this substrate 21 are mild, various materials other than semiconductors can be used.

In addition, the material used for the metal film 23 is one that is difficult to emit photoelectrons when irradiated with light, that is, has a large amount of work to become excited to emit photoelectrons, and has high heat resistance. For example, chromium (Cr), tantalum (
Metals such as Ta), tungsten (W), and platinum (pt) are preferred.

However, electrically conductive films other than metals can also be used as long as the above conditions are met.

In this way, when CsSb is used as a photoelectric film that emits photoelectrons, the photoelectric film can be excited by visible light with a wavelength of 5,500 to 7,000, for example, -M
A large number of photoelectrons can be emitted from the photoelectric film using a light source such as a halogen lamp available in the United States. That is, if CsSb is used as the photoelectric film, 5,500 ~
By irradiating the photoelectron transfer mask with light of 7,000 wavelengths, a large amount of photoelectrons can be stably and continuously emitted.

FIG. 2 is a diagram schematically showing the steps of the method for manufacturing a photoelectronic transfer mask of the present invention.

First, as shown in FIG. 2(a), a metal film 22 is deposited on a substrate 21 to a thickness of about 100 to 3,000 layers.

Here, the material used for the metal film 22 is Cr+Ta, for example, which takes a large amount of work to reach an excited state that emits photoelectrons and has high heat resistance.

Metals such as W and Pt are preferred. That is, among the conditions required for the material used as the metal film 22, the condition that the amount of work required to reach an excited state that emits photoelectrons is large is that when the photoelectron transfer mask 2 is irradiated with light, This is because only the photoelectric film 23 should emit photoelectrons, and the metal film 22 should not emit photoelectrons. Moreover, the condition that the heat resistance is high is to prevent the surface of the metal film 22 from being oxidized or the pattern formed by the metal film 22 from deforming due to heating performed in the manufacturing process.

Next, as shown in FIG. 2(b), ten to ten people apply the sb film 22a on the metal film 22 in a predetermined pattern.
It is formed to a thickness of about ,000 people.

The formation of the SB film 22a having a predetermined pattern can be performed by an etching method, a lift-off method, etc., which are used in boat fishing.

Subsequently, as shown in FIG. 2(c), the substrate 21 is heated to approximately 50° C. to 200″C using a heater 24 or the like.
Furthermore, as shown in FIG. 2(d), Cs atoms 23b are deposited in vacuum while heating the substrate 21. Then, Cs atoms 23b are deposited on the sb film 23a and reacted to form a CsSb film 23 in a predetermined pattern. Here, the substrate 21 is heated to approximately 50°C to 200″C.
This is to cause the b film 23a and the Cs atoms 23b to react quickly. In addition, the heating of the substrate 21 and the vapor deposition and reaction steps of the Cs atoms 23b in FIGS. 2(C) and 2(d) are performed by photoelectronic image transfer of the substrate 21 on which the metal film 22 is deposited and the sb film 23a having a predetermined pattern is formed. It is more practical to place it in the exposure processing chamber of the apparatus and to perform the heating, evaporation and reaction steps of the C8 atoms 23b while keeping the inside of the exposure processing chamber in a vacuum state. This is because it is preferable not to contact the CsSb film 23 with the film type 3.

Then, as shown in FIG. 2(e), while heating the substrate 21, C8 atoms 23b are deposited and reacted on the sb film 23a to form a CsSb film 23 in a predetermined pattern. Here, it is preferable that the molar composition ratio of CsSb film 23 film type 3:Sb is 3:l. This Cs:S
One guideline for when the molar composition ratio of b is about 3:1 is that the color of the CsSb film 23 changes from metallic color to yellow to transparent red. Also, CsS
The molar composition ratio of film type 3:Sb of the b film 23 does not need to be strictly 3:1, and a ratio of about 3:1 can be used satisfactorily. Furthermore, a layer of Cs atoms 23b is also formed on the surface of the metal film 22 in the areas where the CsSb film 23 is not formed. A large amount of photoelectrons are not emitted from the photoelectrons 22, and this poses no practical problem. As described above, the CsSb film 23 having a predetermined pattern can be formed on the film shape 321.

FIG. 3 is a diagram schematically showing a photoelectronic image transfer apparatus using a photoelectronic transfer mask of the present invention, where ■ is an exposure processing chamber, 2 is a photoelectronic transfer mask, 3 is a wafer (sample to be exposed), and 4 is a light source, and 5 is a reflecting mirror.

Using such an apparatus, a photoelectronic transfer mask 2 and a wafer 3 are placed facing each other in an exposure processing chamber 1 kept in a high vacuum, and light from a light source 4 is reflected by a reflecting mirror 5 to form a mask 2. irradiate the surface with light. In this apparatus, light from a light source 4 is reflected by a reflecting mirror 5 to irradiate the surface of the mask 2. However, the light source 4 is provided below the exposure processing chamber l, and the light is directly applied to the mask without using the reflecting mirror 5. It goes without saying that the surface of 2 may be irradiated. By irradiating the surface of the mask 2 with light in this way, photoelectrons 8 are generated from the surface of the mask 2 (the photoelectric film 23 made of CsSb).

Then, the photoelectron 8 is applied to the surface of the sample to be exposed such as the wafer 3.
is irradiated, and the photoelectron image is transferred onto a wafer 3 or the like. At this time, for example, a high voltage of about -80 KV is applied to the mask 2 side, and a uniform magnetic field is applied with the mask 2 side and the wafer 3 side serving as N poles 6 and S poles 7, respectively. It is designed to assist the emission of photoelectrons 8 output from the mask 2 and to accurately converge the photoelectrons 8 emitted from the mask 2 onto the surface of the wafer 3.

According to the above-described photoelectronic transfer mask and its manufacturing method, the number of manufacturing steps can be reduced (about 1/2) and the material cost can be reduced (about 1/2) compared to when using a GaAs semiconductor.
115) and an increase in the duration of photoelectron emission stability (approximately 10 times). Also, Ag-
Even when compared to the case of using 0-Cs, advantages such as an increase in the amount of photoelectron emission (approximately 10 times) and an increase in the duration of the stability of photoelectron emission (approximately 5 times) are recognized.

[Effects of the Invention] As detailed above, the photoelectric transfer mask according to the present invention applies a photoelectric film made of cesium antimonide so as to draw a predetermined pattern on an electrically conductive film deposited on a substrate surface. By forming such a structure, it is possible to continuously emit a large number of photoelectrons by irradiating light output from a commonly available light source without using a special light source.

In addition, the photoelectronic transfer mask of the present invention includes an electrically conductive film deposited on a substrate, an antimony film of a predetermined pattern formed on the electrically conductive film, and cesium deposited on the antimony film of the predetermined pattern in a vacuum. and react, whereby a cesium antimonide film having a predetermined pattern is formed on the electrically conductive film, and a photoelectron transfer mask capable of continuously emitting stable photoelectrons can be easily manufactured.

[BRIEF DESCRIPTION OF THE DRAWINGS] FIG. 1 is a cross-sectional view schematically showing an embodiment of a photoelectron transfer mask according to the present invention, and FIG. 3 is a diagram schematically showing a photoelectronic image transfer device to which the photoelectronic transfer mask of the present invention is applied, and FIG. 4 is a sectional view schematically showing an example of a conventional photoelectronic transfer mask. . (Explanation of symbols) 1... Exposure processing chamber, 2... Photoelectronic transfer mask, 3... Wafer, 4... Light source, 5... Reflector, 6... N pole, 7...・・S pole,
8... Photoelectron, 21... Substrate, 22...
- Metal film, 23...CsSb film.

Claims (1)

[Claims] 1. A substrate (21), an electrically conductive film (22) deposited on the surface of the substrate (21), and a predetermined pattern formed on the electrically conductive film (22). A photoelectric transfer mask comprising: a photoelectric film (23) made of cesium antimonide (CsSb); 2. The cesium antimonide forming the photoelectric film has a cesium (Cs):antimony (Sb) molar composition ratio of 3.
:1. The mask according to claim 1. 3. The mask according to claim 1, wherein the substrate is formed of a semiconductor material. 4. The mask according to claim 1, wherein the electrically conductive film is formed of a metal film. 5. Depositing an electrically conductive film on a substrate, forming an antimony film with a predetermined pattern on the electrically conductive film, and depositing and reacting cesium on the antimony film with the predetermined pattern in a vacuum to form a predetermined pattern. A method for manufacturing a photoelectronic transfer mask, comprising forming a cesium antimonide film on the electrically conductive film. 6. The method according to claim 5, wherein the substrate is heated to 50°C to 200°C when cesium is deposited and reacted on the antimony film in vacuum. 7. The method according to claim 5, wherein when cesium is deposited and reacted on the antimony film in vacuum, the molar composition ratio of cesium:antimony is 3:1.