JP2001267207A - Electron beam exposure mask, its manufacturing method, and electron beam exposure system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the productivity of an electron beam exposure mask and, at the same time, to reduce the manufacturing cost and maintenance cost of the mask. SOLUTION: The electron beam exposure mask is provided with a mask body 2 having a through port 2a for leading an electron beam to a substrate to be irradiated with the beam and a thin film 3 for forming pattern hole which is laminated upon the electron beam emitting side of the body 2 through a thin protective film 4 and has through holes 3a for forming electron beam passing holes communicating with the through port 2a. The mask is also provided with a thin conductive film 5 for suppressing charge up laminated upon the portion of the thin film 3 corresponding to an area to be irradiated with the electron beam including the internal surfaces of the through holes 3a and, at the same time, a thin dielectric film 6 is laminated upon the thin film 5 so as to cover the film 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an electron beam exposure mask used for performing electron beam exposure in a semiconductor manufacturing process, a method for manufacturing the same, and an electron beam exposure apparatus.

[0002]

2. Description of the Related Art In recent years, research and development of circuit pattern fine processing technology such as lithography have been rapidly progressing with the increase in density and integration of semiconductor integrated circuits.
Conventionally, this type of lithography technique has been adopted for an electron beam exposure mask as shown in FIG. The electron beam exposure mask will be described with reference to FIG.

The mask body 42 has through holes 42a for forming electron beam transmitting holes which are opened on both front and back surfaces, and is entirely formed of a silicon (Si) substrate. On the electron beam irradiation side of the mask body 42, a pattern hole forming thin film 43 having a through hole 43a for forming an electron beam transmitting hole communicating with the through hole 42a is laminated. A conductive thin film 44 for suppressing charge-up is laminated on the electron beam irradiation side of the mask body 42 and the pattern hole forming thin film 43 so as to cover the electron beam irradiation region.

The pattern hole forming thin film 43 is formed entirely of silicon (Si) and has a thickness of about 10 μm.
The size is set to m to 20 μm. Conductive thin film 44
Is formed entirely of a heavy metal such as tungsten (W) or gold (Au).

[0005] Manufacturing of the electron beam exposure mask having the above structure is performed as follows. First, a pattern hole forming thin film 43 is laminated on the surface of the mask body (Si substrate) 42.

Next, the pattern hole forming thin film 43 and the Si substrate 42 are subjected to an etching process using a dry etching method or a crystal orientation-dependent wet etching method, so that the electron beam transmitting pattern holes 43a and the through holes 42a are respectively formed. To form Then, a conductive thin film 44 is laminated on the surface (electron beam irradiation area) of the pattern hole forming thin film 43 by a vacuum evaporation method or a sputtering method. Thus, an electron beam exposure mask can be manufactured.

Exposure using an electron beam exposure mask of this kind is performed in a vacuum chamber. At this time, residual gas (resist on a substrate to be transferred and gas scattered from a lens barrel wall) in the vacuum chamber is reduced by an electron beam. Carbonized by irradiation,
Contaminants mainly composed of carbon are generated.

[0008]

In the conventional electron beam exposure mask, the outermost layer of the mask body 42 is a conductive thin film 44 having a large surface energy. Carbide) adhered at the time of exposure, and easily deteriorated the shape of the exposed pattern. As a result, there is a problem that the mask life is reduced and the mask must be replaced frequently, which not only reduces the productivity but also increases the manufacturing cost and the maintenance cost.

Note that Japanese Patent Application Laid-Open No. 5-36591 discloses "X
Although the prior art is disclosed as a "method of manufacturing a line mask", it discloses "forming a high-precision X-ray absorber thin film pattern", but "increases productivity and reduces manufacturing costs." There is no disclosure of means for solving the conventional problem of "reducing cost."

The present invention has been made in view of such circumstances, and focuses on the fact that carbide is unlikely to adhere to a dielectric having a small surface energy. The extremely simple structure of stacking body thin films can extend the life of the mask, thereby improving productivity,
An object of the present invention is to provide an electron beam exposure mask capable of reducing the manufacturing cost, a method of manufacturing the same, and an electron beam exposure apparatus.

[0011]

In order to achieve the above object, an electron beam exposure mask according to claim 1 of the present invention comprises:
A mask body having an opening for forming an electron beam inlet, and a pattern hole having a through hole for forming an electron beam transmission hole which is laminated on the electron beam irradiation side of the mask body via a protective thin film and communicates with the opening. A thin film for forming a patterned hole, a conductive thin film for suppressing charge-up is laminated on a portion corresponding to an electron beam irradiation area including an inner surface of a through hole in the thin film for forming a pattern hole, and a dielectric film covering the conductive thin film is provided. It has a configuration in which body thin films are laminated. Therefore, the outermost layer of the mask becomes a dielectric thin film, thereby preventing carbides generated during exposure from adhering to the outermost layer of the mask. The charge-up due to electron beam irradiation can be prevented by removing a part of the dielectric thin film on the outer periphery of the mask body to expose the lower conductive thin film and grounding the exposed portion.

According to a second aspect of the present invention, in the electron beam exposure mask of the first aspect, the dielectric thin film is made of silicon carbide,
The structure is made of any one of diamond and graphite. Therefore, the mask outermost layer is a dielectric thin film made of any one of silicon carbide, diamond, and graphite, and adhesion of carbide generated at the time of exposure to the mask outermost layer is reduced.

According to a third aspect of the present invention (a method of manufacturing an electron beam exposure mask), a thin film for forming a pattern hole having a through-hole for forming an electron beam transmission hole is preliminarily provided on an anti-irradiation side of the electron beam via an etching protection thin film. A part of the protective thin film is removed from the laminated mask body to form an opening for forming an electron beam introduction port communicating with the through hole, and then corresponds to an electron beam irradiation area including the inner surface of the opening. In this method, a conductive thin film for suppressing charge-up is laminated on a portion, and then a dielectric thin film covering the conductive thin film is laminated on the mask body. Accordingly, the mask outermost layer becomes a dielectric thin film, and a mask is obtained that prevents carbides generated during exposure from adhering to the mask outermost layer.

According to a fourth aspect of the present invention, in the method of manufacturing an electron beam exposure mask according to the third aspect, before laminating the pattern hole forming thin film, a protective thin film is laminated on the side of the mask body opposite to the electron beam irradiation. There is a way. Therefore, the protective thin film on the side opposite to the electron beam irradiation serves as a mask when forming an opening in the mask body.

The invention according to claim 5 is the invention according to claim 3 or 4.
In the method for manufacturing an electron beam exposure mask described above, a conductive thin film is laminated on the electron beam non-irradiation side of the mask body. Accordingly, a dielectric thin film as an outermost layer of the mask is laminated on the side opposite to the electron beam irradiation side of the mask body, and a mask is obtained which prevents carbides generated during exposure from adhering to the outermost layer of the mask.

According to a sixth aspect of the present invention, there is provided an electron beam exposure apparatus including the electron beam exposure mask according to the first or second aspect. Therefore, the outermost layer of the electron beam exposure mask becomes a dielectric thin film, and the adhesion of carbide generated at the time of exposure to the outermost layer of the mask is prevented.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described.
This will be described with reference to the drawings. FIG. 1 is a sectional view showing an electron beam exposure mask according to the first embodiment of the present invention. In the figure, an electron beam exposure mask for fine pattern high-precision drawing and high-precision reduction transfer indicated by reference numeral 1 is a mask body 2
It has.

The mask body 2 has a through-hole 2a as an opening for forming an electron beam introduction port which is opened on both front and back sides (in the direction of electron beam irradiation), and is entirely formed of a silicon (Si) substrate or the like. On the electron beam irradiation side of the mask body 2, a pattern hole forming thin film 3 having an electron beam transmission forming through hole 3a communicating with the through hole 2a is laminated via a protective thin film (etching protective film) 4. .

The mask body 2 is located in a region corresponding to an electron beam irradiation region including the inner surface of the through hole 3a and a region other than the electron beam irradiation region (electron beam non-irradiation region). A conductive thin film 5 for suppressing charge-up is laminated so as to cover the conductive film. Further, a dielectric thin film 6 is laminated on the mask body 2 so as to cover the conductive thin film 5 as an outermost layer of the mask.

The pattern hole forming thin film 3 is entirely formed of silicon (Si) and has a thickness of about 10 μm.
The size is set to の 20 μm. The protective thin film 4 is entirely composed of silicon dioxide (SiO ₂ ), silicon nitride (Si ₃ N ₄ ),
It is formed of silicon carbide (SiC) or diamond or the like, and has a thickness of about 0.1 μm to 1 μm.

The conductive thin film 5 is entirely formed of gold, platinum, tungsten, tantalum, molybdenum or an alloy of these metals, and has a thickness of about 0.5 μm to 1 μm.
m is set. The dielectric thin film 6 is formed of any one of silicon carbide, diamond, and graphite whose surface energy is smaller than the surface energy of the conductive thin film 5 and has a thickness of about 0.1 μm.
The size is set to 1 μm.

The surface energy of the graphite in the (100) plane is about 1/173 that of tungsten.
(DH Bukley, Surface)
effect in adhesion, furict
ion, wear and lubrication
h, Elsevier, p. 245, 1981).

Next, a method of manufacturing an electron beam exposure mask will be described with reference to FIGS. FIG.
(A)-(f) is sectional drawing shown in order to demonstrate the manufacturing method of the electron beam exposure mask which concerns on 1st embodiment of this invention. The manufacture of the electron beam exposure mask in the present embodiment includes “lamination of a protective thin film”, “lamination of a thin film for forming a pattern hole”, “formation of a through hole for forming an electron beam transmission hole”, and “an opening for forming an electron beam introduction port”. Part (through hole) formation, lamination of conductive thin film, and lamination of dielectric thin film.

[Lamination of Protective Thin Film] First, silicon dioxide (SiO ₂ ) is placed on both front and back surfaces of the mask body (silicon substrate) 2.
The protective thin film 4 composed of the above is laminated. At this time, the protective thin film 4
Is set to a size of about 0.1 μm to 1 μm.
Next, as shown in FIG. 3A, an etching process is performed on the protective thin film 4 on the back surface side (the side opposite to the electron beam irradiation) of the silicon substrate 2 by using an ultraviolet exposure technique and a dry etching technique, as shown in FIG. By performing this, the pattern opening 4a is formed.

[Lamination of Electron Beam Non-Transparent Thin Film] First, as shown in FIG. 1B, the pattern hole forming thin film 3 made of silicon (Si) or the like is It is laminated on the irradiation area side. At this time, the substrate temperature was set to about 600 ° C. and the reaction gas was monosilane gas (N ₂ as a carrier gas) (however, the film formation conditions were the structure of the reaction chamber, the substrate heating method, and the reaction gas). It varies slightly depending on the supply method and the like.
A compressive stress of Pa or less is applied. The thickness of the pattern hole forming thin film 3 is set to a size of about 10 μm to 20 μm.

Thereafter, the mask body 2 on which the pattern hole forming thin film 3 is laminated is placed in a nitrogen atmosphere at 650 ° C. to 700 ° C.
The pattern hole forming thin film 3 is made to have a polycrystalline structure by performing an annealing treatment at the substrate temperature described above, and a tensile stress of 0 Pa to several MPa is applied to the pattern hole forming thin film 3 at the same time. The lamination of the pattern hole forming thin film 3 on the protective thin film 4 is as follows.
In addition to the low pressure CVD method, it can be performed by bonding by an anodic bonding method.

[Formation of Through Hole for Forming Electron Beam Transmission Hole]
First, a desired resist pattern R is formed on the electron beam irradiation side of the pattern hole forming thin film 3 as shown by a two-dot chain line in FIG. Next, the resist pattern R is used as a protective film (mask), and the thin film 3 for forming a pattern hole is subjected to dry etching to form a through hole 3a for forming an electron beam transmitting hole as shown in FIG. After that, the resist pattern R is removed.

[Formation of an opening for forming an electron beam inlet]
For example, using a heated potassium hydroxide (KOH) aqueous solution and using the protective thin film 4 on the electron beam irradiation side as a mask as shown in FIG.
Until the surface is exposed, the mask body 2 is subjected to an etching process to form the through-hole 2a. At this time, tapered surfaces 2a ₁ with opening diameter that increases toward the electron beam emission side of the electron beam incident side in the through hole 2a is formed.

[Lamination of Conductive Thin Film] First, as shown in FIG. 3E, using, for example, hydrofluoric acid, the externally exposed portion of the protective thin film 4 on the side opposite to the electron beam and the protective film 4 on the side of the electron beam. The protective film 4 (the protective thin film on the electron beam irradiation side is an externally exposed portion) is removed by performing a wet etching process. Next, a metal material such as gold (Au) or platinum is applied to a portion corresponding to the electron beam irradiation region and a region other than the electron beam irradiation region (an electron beam non-irradiation region including the electron beam non-irradiation region) by the rf sputtering method. The conductive thin film 5 is laminated. At this time, the thickness of the conductive thin film 5 is set to a size of about 0.5 μm to 1 μm. Note that the conductive thin film 5 may be laminated only in the electron beam irradiation area.

"Lamination of dielectric thin film"
Sputtering method, plasma CVD method or ECR-
Using a CVD method or the like, a dielectric thin film 6 such as silicon carbide, graphite, or diamond is laminated on the mask main body 2 so as to cover the conductive thin film 5 as shown by a two-dot chain line in FIG. At this time, if a part of the conductive thin film 5 is covered with a jig or the like and the jig or the like is removed after laminating the film, the conductive thin film 5 can be grounded when the mask 1 is used. The thickness of the dielectric thin film 6 is set to a size of about 0.1 μm. In this way, it is possible to obtain the mask 1 that prevents the contaminant (carbide) generated at the time of exposure from adhering to the mask outermost layer (electron beam irradiation region).

The electron beam exposure mask manufactured by such a method is applied to an electron beam exposure apparatus as shown in FIG. About this electron beam exposure device,
This will be described with reference to FIG. FIG. 3 is a cross-sectional view schematically showing an electron beam exposure apparatus according to the first embodiment of the present invention. In FIG. 3, the same reference numerals as in FIG. 1 denote the masks, and a detailed description thereof will be omitted. In the figure, an electron beam exposure apparatus indicated by reference numeral 21 includes a stage 22, a beam deflector 23,
It comprises a deflecting lens 24, a mask 1 and an electron gun 25, and is arranged in a vacuum chamber (not shown).

The stage 22 comprises a sample stage for positioning the substrate 26 to be transferred, and is arranged below the electron gun 25. The beam deflector 23 includes a first beam deflector 23 a to a third beam deflector 23 arranged in parallel in the vertical direction.
c, and is disposed between the electron gun 25 and the stage 22.

The deflection lens 24 comprises a first deflection lens 24a to a third deflection lens 24c which are arranged in the vertical direction.
It is arranged between the first beam deflector 23a and the third beam deflector 23c. That is, the first deflection lens 24a
Is disposed between the first beam deflector 23a and the second beam deflector 23b, and the second deflection lens 24b and the third deflection lens 24c are disposed between the second beam deflector 23b and the third beam deflector 23c. Are located in

The mask 1 is disposed between the second deflecting lens 24b and the third deflecting lens 24c with the mask body 2 and the pattern hole forming thin film 3 as lower and upper portions, respectively. The electron gun 22 is composed of an electron beam irradiation device that irradiates the transfer substrate 26 on the stage 22 with the electron beam EB, and is disposed above the first beam deflector 23a.

Exposure by the electron beam exposure apparatus configured as described above is performed as follows. That is, the electron beam EB emitted from the electron gun 25 is deflected by the beam deflector 23 and the deflecting lens 24, and is transmitted through the pattern hole of the mask 1 (the pattern hole 6 a for transmitting the electron beam of the dielectric thin film 6). Exposure is performed by irradiating the upper transfer substrate 26 (photosensitive resist) at a predetermined reduction magnification.

[0036]

As described above, according to the present invention, since the dielectric thin film covering the conductive thin film is laminated on the mask body, the outermost layer of the mask becomes a thin film layer having a small surface energy, which is generated at the time of exposure. It is possible to prevent carbides from adhering to the electron beam irradiation area. Therefore, since the occurrence of deterioration of the exposure pattern shape can be suppressed, the life of the mask can be reliably increased, the productivity can be improved, and the manufacturing cost and maintenance cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an electron beam exposure mask according to a first embodiment of the present invention.

FIGS. 2A and 2F are cross-sectional views illustrating a method for manufacturing an electron beam exposure mask according to the first embodiment of the present invention.

FIG. 3 is a cross-sectional view schematically showing an electron beam exposure apparatus according to the first embodiment of the present invention.

FIG. 4 is a cross-sectional view showing a conventional electron beam exposure mask.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 electron beam exposure mask 2 mask body (silicon substrate) 2 a through hole for forming electron beam inlet 3 thin film for forming pattern hole 3 a through hole for forming electron beam transmission hole 4 protective thin film 5 conductive thin film 6 dielectric thin film 6 a Pattern hole for electron beam transmission 6b Electron beam inlet

Claims (6)

[Claims] 1. A mask body having an opening for forming an electron beam introduction port, and an electron beam transmitting hole formed on the electron beam irradiation side of the mask body via a protective thin film and communicating with the opening. A thin film for forming a pattern hole having a through hole, a conductive thin film for suppressing charge-up is laminated on a portion corresponding to an electron beam irradiation area including an inner surface of the through hole in the thin film for forming a pattern hole, An electron beam exposure mask, wherein a dielectric thin film covering a conductive thin film is laminated. 2. The electron beam exposure mask according to claim 1, wherein said dielectric thin film is formed of any one of silicon carbide, diamond and graphite. 3. A mask body in which a pattern hole forming thin film having a through hole for forming an electron beam transmitting hole is preliminarily laminated on the electron beam irradiation side via a protective thin film to remove a part of the protective thin film. Forming an opening for forming an electron beam introduction port communicating with the through hole, and then laminating a conductive thin film for suppressing charge-up on a portion corresponding to an electron beam irradiation region including an inner surface of the opening. A method for manufacturing an electron beam exposure mask, comprising laminating a dielectric thin film covering the conductive thin film on the mask body. 4. The method of manufacturing an electron beam exposure mask according to claim 3, wherein a protective thin film is laminated on the electron beam non-irradiation side of the mask body before laminating the pattern hole forming thin film. 5. The method according to claim 3, wherein the conductive thin film is laminated on the side of the mask body opposite to the electron beam irradiation.
Or the method for manufacturing an electron beam exposure mask according to 4. 6. An electron beam exposure apparatus comprising the electron beam exposure mask according to claim 1.