JP2000156343A - Mask for x-ray exposure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the thickness of the X-ray absorber of a mask for X-ray exposure using synchrotron radiation light as exposed light by selecting the material of the absorber so that the absorber may contribute to improvement of the accuracy of X-ray exposure. SOLUTION: A mask for X-ray exposure is provided with an X-ray mask section in which a pattern composed of an X-ray absorber 5 is formed on a membrane film 6 and a supporting body 7 which supports the mask section. Synchrotron radiation light 4 made incident to the X-ray mask section and having its maximum light intensity at a wavelength of 0.6-1 nm is used as exposed light, and the X-ray absorber 5 is formed to contain such an element that has a density/atomic weight of >=0.085 g/cm3 and an L-shell absorption edge at a wavelength of 0.75-1.6 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray exposure mask suitable for X-ray exposure used in semiconductor production and the like, a method of manufacturing the mask, an X-ray exposure method and an exposure apparatus using the mask, and furthermore, The present invention relates to a device production method and the like using the mask.

[0002]

2. Description of the Related Art In recent years, with the miniaturization of semiconductor integrated circuits,
An equal-size X-ray exposure method has been proposed in which an X-ray having a shorter wavelength is used to bring a mask and a wafer substrate close to each other and expose and transfer a mask pattern onto the wafer substrate.

As shown in FIG. 6, the X-ray exposure is performed by irradiating an X-ray 4 onto a substrate 3 through an X-ray exposure mask 1 on which a mask pattern is drawn. X
The mask pattern is transferred to the line resist 2.
The mask 1 has a membrane (supporting film) 6 of a light element such as silicon nitride, silicon carbide, silicon, or diamond having a thickness of 1 to 5 μm that easily transmits X-rays, and an X-ray absorber pattern 5 ′ for shielding X-rays. And only the X-rays 4 incident on the mask 1 that have entered the portion without the absorber penetrate the mask 1 and reach the surface of the resist 2 so that the pattern is transferred. Becomes Conventionally, heavy metals such as W, Ta, and Au have been used as X-ray absorber materials. Other X-ray absorber materials include Fe, Co,
Ni, Cu, Zn, Nb, Mo, Pd, Ag, Pt and alloys thereof have been proposed.

In the conventional examples of the X-ray absorber material used for these X-ray exposure masks, the effect only when a specific single wavelength light source is used for exposure has been examined. No consideration is given to absorption of the absorber when a light source having a relatively wide wavelength range is used, mask contrast and phase characteristics, and setting of a suitable wavelength range and intensity profile of a synchrotron light source. For example,
JP-A-5-13309 discloses that Co, Ni, Cu,
Zn and their alloys have been proposed as absorber materials for exposure to X-rays at wavelengths of 1-1.5 nm, but Co, Ni, at a specific single wavelength of 1.225 nm, which is the center of this wavelength range. It only shows the absorption of Cu and Zn and the thickness of the absorber when the mask contrast is 10, and is obtained when exposure is performed using synchrotron radiation over a wide wavelength range of 1 to 1.5 nm. No consideration is given to the optimization of the exposure wavelength at the time of actual X-ray exposure transfer using the absorption characteristics, the mask contrast, and those absorber materials.

Similarly, another known document, Japanese Patent Publication No. 7-955
No. 06 discloses Fe, Co, Ni, and Ni for shielding X-rays and easy etching by ion etching.
Cu, Zn, Nb, Mo, Pd, Ag, Ta, W, P
As shown in FIG. 7, the transmission pattern 1 of resin or silicon dioxide different from the absorber forming the absorber pattern 5 ′ on the membrane 6 using t, Au and their alloys as the absorber.
Although a mask having 0 has been proposed, no consideration is given to the setting of a suitable wavelength of a light source used for exposure and the phase shift effect.

A phase shift mask has been proposed as a conventional example for improving the resolution at the time of transfer of an X-ray exposure mask using these materials as an absorber. For example, as shown in US Pat. No. 4,890,309. Describes only the phase shift effect when using a specific single-wavelength light source, and obtains the phase characteristics of the absorber when using a light source with a relatively wide wavelength range such as synchrotron radiation, and at that time No consideration is given to the absorption characteristics and mask contrast, the setting of a suitable synchrotron light source wavelength range, and the absorber material suitable for that wavelength range.

[0007] Also in the exposure apparatus, in the exposure method utilizing the oscillation of synchrotron radiation or reflection by a fixed X-ray mirror, a large difference occurs in the wavelength distribution depending on the exposure position.
There is a problem that the amount of phase shift greatly varies depending on the exposure position. Therefore, there is a need to develop an X-ray exposure mask suitable for synchrotron radiation.

[0008]

The preferred wavelength range of the light source used in actual 1: 1 X-ray exposure is Fresnel diffraction, which governs the resolution of the transferred pattern, and secondary electron emission generated in the resist by X-rays. It depends on the process. In Fresnel diffraction, the narrower the gap between the mask and the wafer, the shorter the exposure wavelength, the lower the wavelength, the higher the resolution, and the higher the resolution. On the other hand, the secondary electron range uses short-wavelength X-rays for exposure. The resolution sometimes deteriorates due to the exposure by the secondary electrons. Therefore, due to the two relations between the diffraction effect and the secondary electron effect, the exposure wavelength of the X-ray used is 0.6 to
It has been shown that the wavelength range of 1 nm is excellent in resolution, and it is desirable to use X-rays of 0.6 to 1 nm in exposure.

However, in an actual exposure or a conventional X-ray exposure mask, only a suitable absorber material is mainly assumed at one specific wavelength, and the wavelength range is set to 0.1.
No studies have been made on an absorber material and an X-ray exposure mask suitable for synchrotron radiation having a wavelength of 6 to 1 nm. Since the absorption and phase characteristics of a substance greatly depend on the X-ray wavelength used, it is necessary to select a material in accordance with the wavelength used for exposure, but synchrotron radiation is a continuous spectrum with a wide wavelength range. Suitable absorber materials and mask materials differ depending on the spectral characteristics.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a synchrotron radiation light having a maximum light intensity of light incident on a mask portion at a wavelength of 0.6 to 1 nm. X-ray exposure using as an exposure light source,
An object of the present invention is to provide a mask for X-ray exposure that enables a thinner absorber by using a material having a large absorption in the exposure wavelength range and can contribute to improvement of exposure accuracy in X-ray exposure.

Another object of the present invention is to provide a phase shift amount in X-ray exposure using synchrotron radiation having a maximum light intensity of 0.6-1 nm in wavelength of light incident on a mask portion as an exposure light source. An object of the present invention is to provide a mask for X-ray exposure that enables the resolution of a transfer pattern to be improved by using a material in which X is controlled, thereby contributing to an improvement in exposure accuracy in X-ray exposure.

Another object of the present invention is to provide a method of manufacturing an X-ray exposure mask which can easily manufacture the above-described X-ray exposure mask.

Another object of the present invention is to provide a pattern exposure method, a pattern exposure apparatus, a semiconductor device production method, and the like which can perform good X-ray exposure using the above-mentioned X-ray exposure mask. It is in.

[0014]

(Structure) In order to solve the above-mentioned problem, the present invention employs the following structure.

(1-1) An X-ray exposure mask comprising: an X-ray mask having a pattern formed of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask. The synchrotron radiation having the maximum light intensity of the light incident on the X-ray mask portion at a wavelength of 0.6 to 1 nm is used as an exposure light source, and the X-ray absorber material has a density / atomic weight of 0.085 [g / cm ³ ] or more, and an element having an L-shell absorption edge at a wavelength of 0.75 to 1.6 nm, or a density / atomic weight of 0.04 [g / cm ³ ] or more, and an M-shell absorption edge having a wavelength It contains an element having a wavelength of 0.75 to 1.6 nm.

(1-2) The X-ray absorber material is a single element, an alloy, or a laminated film. (1-3) In the X-ray absorber material, the density / atomic weight is 0.0
85 [g / cm ³ ] or more and L-shell absorption edge at a wavelength of 0.75
Elemental elements having a wavelength of ~ 1.6 nm are Co, Ni, Cu, Z
n, Ga, and a density / atomic weight of 0.040 [g / cm]
³ ] and M-shell absorption edge at a wavelength of 0.75 to 1.6 nm
Is a lanthanoid rare earth element (La to Lu) having an atomic number of 57 to 71.

(2) The X-ray absorber material is Co, Ni, C
u, Zn, Ga, La, Ce, Pr, Nd, Pm, S
m, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb
Contains at least one element of

(3-1) An X-ray exposure mask comprising: an X-ray mask having a pattern of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask. Synchrotron radiation having a maximum light intensity of 0.6 to 1 nm of light incident on the X-ray mask portion is used as an exposure light source, and the X-ray absorber has an L-shell absorption edge or an M-shell absorption edge having a wavelength of 0. A first material made of any of the elemental elements having a wavelength of 0.5 to 1.5 nm,
It is characterized by being an alloy or a laminated film of any of the single elements having a wavelength of 0.75 nm.

(3-2) Co, Ni, C as the first material
u, Zn, Ga, any one of lanthanoid rare earth elements (La to Lu) having an atomic number of 57 to 71,
Using any element of atomic numbers 72 to 80 (Hf to Hg) as the material of

(4-1) An X-ray exposure mask comprising: an X-ray mask having a pattern formed of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask. As the X-ray absorber, all of the L-shell and M-shell absorption edges have the synchrotron radiation light as the exposure light source (as the light intensity, 1 / (1) of the light intensity at the wavelength of the maximum light intensity incident on the X-ray mask portion) (A wavelength region having an intensity of 10 or more is defined as an exposure wavelength region.) A material having an element as a main component which is equal to or shorter than the shortest wavelength of the exposure wavelength region or equal to or longer than the longest wavelength of the exposure wavelength is used.

(4-2) The absorber is a single element, Ga (31) having an atomic number of 31, or an alloy thereof, or a laminated film.

(4-3) The element used for the absorber is Co (27) -Zn (30) with atomic number 27-30 or Ga
(31), Rh (45) to Ag of atomic numbers 45 to 47
(47), La (57) -Eu of atomic numbers 57-63
(63), Os (76) -Hg of atomic numbers 76-80
(80), At (85) to Fr of atomic numbers 85 to 87
(87), Ac (89) to U (9) having atomic numbers 89 to 92.
It must be one of 2).

(5) X-ray absorber materials are Ti, V, Cr,
Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, T
c, Ru, Rh, Pd, Ag, La, Ce, Pr, N
contain at least one element of d, Pm, Sm, Eu, and Gd.

(6-1) An X-ray exposure mask comprising: an X-ray mask portion having a pattern formed of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask portion. The synchrotron radiation having the maximum light intensity wavelength of the light incident on the X-ray mask portion in the range of 0.6 to 1 nm is used as an exposure light source, and all the L-shell and M-shell absorption edges are used as the X-ray absorber. , 0.65 nm or less, or 1.02
It is characterized by using a material containing, as a main component, an element in a region of nm or more.

(6-2) The X-ray absorber is a single element, Ga (31) having an atomic number of 31, or an alloy thereof, or a laminated film.

(6-3) Elements used for the absorber include Co (27) to Zn (30) having atomic numbers 27 to 30 or Ga
(31), Rh (45) to Ag of atomic numbers 45 to 47
(47), La (57) -Eu of atomic numbers 57-63
(63), Os (76) -Hg of atomic numbers 76-80
(80), At (85) to Fr of atomic numbers 85 to 87
(87), Ac (89) to U (9) having atomic numbers 89 to 92.
It must be one of 2).

(7-1) An X-ray exposure mask comprising: an X-ray mask having a pattern of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask. As the X-ray absorber, all of the L-shell and M-shell absorption edges have an exposure wavelength range of synchrotron radiation as an exposure light source (light at a wavelength of maximum light intensity incident on the X-ray exposure mask as light intensity). The wavelength region having an intensity of 1/10 or more of the intensity is defined as an exposure wavelength region or less, or at least one of the longest wavelengths of the exposure wavelength, and any one absorption edge is from the shortest wavelength of the exposure wavelength region. 0.4n from the shortest wavelength
the first material in the wavelength range up to
The shell and M-shell absorption edges are regions that are shorter than or equal to the shortest wavelength of the exposure wavelength range of the synchrotron radiation light as the exposure light source or longer than the longest wavelength of the exposure wavelength, and one of the absorption edges is the longest wavelength of the exposure wavelength range. And a second material in a wavelength range from 0.6 to 0.6 nm longer than the longest wavelength.

(8-1) An X-ray exposure mask comprising: an X-ray mask portion having a pattern formed of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask portion. The exposure wavelength range (the wavelength range having an intensity of 1/10 or more of the light intensity at the wavelength of the maximum light intensity incident on the X-ray exposure mask as the light intensity) is 0.65.
The synchrotron radiation having a wavelength between 1.0 nm and 1.02 nm is used as an exposure light source, and as the X-ray absorber, all L-shell and M-shell absorption edges are shorter than the shortest wavelength or longer than the longest wavelength of the exposure wavelength range. A first material in a region, and any one absorption edge is in a wavelength range from the shortest wavelength of the exposure wavelength range to a wavelength shorter by 0.4 nm than the shortest wavelength,
All of the L-shell and M-shell absorption edges are in the region not longer than the shortest wavelength or longer than the longest wavelength of the exposure wavelength, and any one absorption edge has a length of 0.6 to more than the longest wavelength in the exposure wavelength range.
It is characterized by using an alloy or a stacked film in which a second material having a wavelength range up to nm longer is combined.

(8-2) As the first material, atomic numbers 41 to 41
52 Nb (41) to Te (52) and atomic number 76 to
Any of Os (76) to U (92) of No. 92 is used, and Co (2) of atomic numbers 22 to 31 is used as the second material.
2) to Zn (30) and La (5) having atomic numbers 57 to 62;
7) Use any of elements Eu to (63).

(8-3) The second material is an alloy with the first material including Ga (gallium) having an atomic number of 31 or a laminated film.

(9-1) An X-ray exposure mask comprising: an X-ray mask portion having a pattern formed of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask portion. It is characterized by having a transmission film pattern different from the X-ray absorber pattern on the membrane film.

(9-2) The difference between the phase of the exposure light passing through the X-ray absorber and the phase of the exposure light passing through the transmission film is controlled by the film thickness of the X-ray absorber and the transmission film.

(9-3) An element having a phase characteristic for canceling phase dispersion generated in the exposure wavelength region of the X-ray absorber material is selected as a material of the transmission film.

(9-4) As for the permeable film material, all the absorption edges are in the exposure wavelength range (from the maximum light intensity to the light intensity
Element or compound consisting of an element whose wavelength is less than or equal to or shorter than the shortest wavelength in the wavelength range having an intensity of up to / 10, or an element having an absorption edge near the shortest wavelength (within 0.1 nm from the shortest wavelength). , Using a laminated film.

(9-5) As the X-ray absorber material, all the absorption edges have an exposure wavelength range (light intensity of 1/1 of the light intensity at the wavelength of the maximum light intensity incident on the X-ray exposure mask).
The wavelength region having an intensity of 0 or more is defined as an exposure wavelength region), a single element, a compound, or a laminated film composed of an element at or below the shortest wavelength, at or above the longest wavelength, or near the longest wavelength (within 0.1 nm from the longest wavelength). Use.

(9-6) As the synchrotron radiation, an exposure wavelength range (a wavelength range having an intensity of 1/10 or more of the light intensity at the wavelength of the maximum light intensity incident on the X-ray mask portion as the light intensity) Range) from 0.65 nm to 1.02
When an exposure light source having a distance between nm is used, Be, B, C, N, O, F, N
a, Si, P, S, Cl, K, Ca, Sc, Ti, V,
Use at least one of Cr, Rb, Sr, Y, Zr, Nb, Mo, I, and Ra.

(9-7) As synchrotron radiation, an exposure wavelength range (a wavelength range having an intensity of 1/10 or more of the light intensity at the wavelength of the maximum light intensity incident on the X-ray mask portion as the light intensity) Range) from 0.65 nm to 1.02
When using an exposure light source having a wavelength of between 500 nm, Co, Ni, Cu, Zn, G
a, Rh, Pd, Ag, La, Ce, Pr, Nd, S
Use at least one of m, Eu, Gd, Tb, Dy, Ho, Pt, and Au, or an alloy thereof.

(9-8) As the synchrotron radiation light, the maximum light intensity of the light incident on the X-ray mask portion is set to a wavelength of 0.7 to 1.
When synchrotron radiation having a wavelength of 2 nm is used, Si, Si ₃ N ₄ , SiC, SiO
_{2. Use} SrO.

(9-9) As the synchrotron radiation light, the maximum light intensity of the light incident on the X-ray mask portion is set to a wavelength of 0.3 to 0.5.
When synchrotron radiation having a wavelength of 7 nm is used, diamond, CaO, Sc ₂ O ₃ , T
Use iO ₂ .

(9-10) As synchrotron radiation, X
The maximum light intensity of light incident on the line mask portion is set to a wavelength of 0.6 to 1
When synchrotron radiation having a wavelength of nm is used, SiO ₂ , SrO, SiC, or Si is used as a material for the transmission film.

(9-11) The same substance as the membrane material is used as the permeable membrane material.

(10-1) An X-ray exposure mask comprising: an X-ray mask portion having a pattern formed of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask portion. When the wavelength region having an intensity of 1/10 or more of the light intensity at the wavelength of the maximum light intensity of the light incident on the X-ray mask portion is the exposure wavelength region, as the X-ray absorber material,
A phase shifter having a maximum and a minimum phase shift amount within a range of ± 10% of an average phase shift amount within the exposure wavelength range is used.

(11-1) In the method of manufacturing an X-ray exposure mask for manufacturing an X-ray exposure mask according to the above (9), a transparent film which has been processed beforehand when forming the absorber. The method includes a step of depositing an absorber on a pattern by a sputtering method or a chemical vapor deposition method, and a heating step performed subsequently.

(11-2) The melting point of the X-ray absorber is 1500 ° C. or less, and the melting point of the permeable film is 1500 ° C. or more.

(11-3) Co, N as an X-ray absorber material
i, Cu, Zn, Ga, Ag, Cd, La, Ce, P
r, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Au
And their alloys.

(12-1) In the method for manufacturing an X-ray exposure mask for manufacturing an X-ray exposure mask according to the above (9), when the transmission film is formed, the absorber processed in advance is used. The method includes a step of depositing a permeable film on a pattern by a sputtering method or a chemical vapor deposition method, and a heating step subsequently performed.

(12-2) The melting point of the absorber is 1500 ° C. or more, and the melting point of the permeable membrane is 1000 ° C. or less.

(13-1) In the method of manufacturing a mask for X-ray exposure, a step of forming a first layer made of a material different from the X-ray absorber on the X-ray transparent thin film, Forming a pattern, forming an X-ray absorber layer on the X-ray transparent thin film and the first layer, and forming a second layer on the X-ray absorber layer to form a surface. The method includes a step of planarizing and a step of simultaneously processing the X-ray absorber layer and the second layer.

(13-2) After the step of forming the X-ray absorber layer on the first layer and before the step of forming the second layer, the X-ray absorber layer is heated to form the first layer. Aggregate embedding in the pattern recess.

(13-3) The step of forming a desired pattern on the first layer includes a step of applying a resist, wherein the second layer is formed by spin coating. And that the coating properties of the second layer are equal.

(13-4) The second layer is a resist, and the application of the resist is performed using the same apparatus as the application of the resist included in the step of forming a desired pattern on the first layer. thing.

(13-5) Instead of forming the second layer and simultaneously etching the layer and the X-ray absorber layer, the X-ray absorber layer is etched or etched as a step of simultaneously processing the X-ray absorber layer. There is a method of polishing.

(13-6) The apparatus used for polishing the X-ray absorber layer fills the polished surface side of the mask with a fluid,
A mechanism for controlling the pressure of the fluid must be provided.

(13-7) The apparatus used for polishing the X-ray absorber layer includes a pedestal for fixing the mask, and a sensor for monitoring the distance between the pedestal and the X-ray transparent thin film of the mask.

(14-1) An X-ray exposure mask according to any one of (1) to (10), and a synchrotron radiation having a maximum light intensity at a wavelength of 0.6 to 1 nm is applied to the mask. A pattern exposure apparatus comprising: an X-ray source for irradiation; and means for projecting and exposing X-rays transmitted through a mask onto a wafer.

(15-1) The mask for X-ray exposure according to any one of (1) to (10) is used, and the maximum light intensity of light incident on the X-ray mask portion is set to a wavelength of 0.6 to 1 nm. A pattern formed on a mask by exposure-transfer onto a wafer using the synchrotron radiation light of the above as an exposure light source.

(16-1) A device production method characterized by producing a semiconductor device using the X-ray exposure mask according to any one of the above (1) to (10).

(Operation) In the present invention, the following two problems are solved. The first problem is that a material capable of obtaining a high mask contrast and having a high absorption for synchrotron radiation having a maximum light intensity wavelength in the exposure wavelength range of 0.6 to 1 nm, which is excellent in resolution, is used for the X-ray absorber. To realize a suitable X-ray exposure mask. A conventional X-ray exposure mask using an absorber material has a problem that it is difficult to form a fine pattern because the absorber must have a large film thickness in order to obtain high mask contrast. Therefore, a material that absorbs much of the synchrotron radiation used for actual exposure and that can provide high mask contrast is required.

The second problem is that the difference | φ ₁ −φ ₂ | between the shift amounts of the phases φ ₁ and φ ₂ of the X-rays that have passed through the X-ray absorber and the mask substrate indicates that the exposure is excellent in resolution. Wavelength 0.6 ~
A suitable X-ray exposure mask and phase shift mask are realized by using, as the absorber, a material that does not exhibit wavelength dependence for 1 nm and has the same shift amount and high mask contrast. At this time, in the exposure method in which the synchrotron radiation light is reflected by the X-ray mirror,
Even if there is a large difference in the wavelength distribution depending on the exposure position, if the phase shift does not show wavelength dependence, uneven exposure and deterioration in resolution can be suppressed.

FIG. 8 of the conventional example (US Pat. No. 4,890,309)
Phase shift mask that inverts the phase of the absorber
, The X-rays transmitted through the absorber 5 ′ and the mask substrate
Each phase φ₁And φ_TwoAbsorber so that is shifted by π
Thickness d_aIs determined. For example, at a wavelength of 0.8 nm
X-ray pattern of absorber made of W (tungsten)
When exposing, if the thickness is 0.5 μm, | φ₁ −φ_Two|
= Π, the purpose can be achieved, but the sink has a wide wavelength range
When performing exposure using rotron radiation, the thickness of the absorber
The phase shift and absorption due to d change with wavelength.
You. Here, the pattern of the absorber made of W having a thickness of 0.5 μm was used.
Synchrotron with a wavelength range of 0.6 to 1 nm
When assuming exposure by synchrotron radiation, the amount of phase shift is set to 0.1.
38π <| φ ₁−φ_Two| <1.32π, a single wavelength
Just taking into account the phase and absorption characteristics of
The desired phase shift effect cannot be obtained.

Therefore, according to the present invention, in the X-ray exposure mask having the membrane 6 and the X-ray absorber pattern 5 as shown in FIG. 1, the membrane 6 forms the pattern 5 by the X-ray absorber. The line absorber is Co, N
i, Cu, Zn, Ga, L of the lanthanoid rare earth element
a, Ce, Pr, Nd, Pm, Sm, Eu, Gd, T
Simple elements of b, Dy, Ho, Er, Tm, Yb, Lu and alloys thereof, and Cr, Mn, Fe, Hf, Ta,
An alloy of any one of W, Re, Os, Ir, Pt, Au, and Hg and any one of lanthanoid rare earth elements (La to Lu) is used. The X-ray 4 has a maximum light intensity of light incident on the X-ray exposure mask of a wavelength of 0.6 to
Synchrotron radiation having a wavelength of 1 nm is used.

In addition to the X-ray exposure mask having the above structure, in the present invention, the X-ray absorber pattern 10 and a transparent film pattern different from the absorber are formed on the membrane 6 shown in FIGS.
An X-ray exposure mask having a mask characteristic of (8, 8 ′, 8 ″) is used. At this time, as the X-ray absorber material,
All of the absorption edges are in the region of the shortest wavelength or less or the longest wavelength or more in the exposure wavelength range (wavelength range having an intensity of 1/10 or more of the maximum light intensity incident on the X-ray exposure mask as light intensity). It is characterized by using a single element, a compound, or a laminated film composed of a certain element, and as a permeable film material, an element whose all absorption edges are in a region shorter than the shortest wavelength of the exposure wavelength region or longer than the longest wavelength. Alternatively, a single element, a compound, or a stacked film including an element having an absorption edge near the shortest wavelength (within 0.1 nm from the shortest wavelength) is used. At this time, a substance made of an element having a phase characteristic suitable for canceling the phase dispersion of the absorber in the exposure wavelength region is selected as the permeable film material.

As described above, in the present invention, the diffraction effect and the secondary electron effect are most suppressed by selecting the material of the absorber as in claims 1 and 2, and a high-resolution transfer pattern can be obtained. Using X-rays in the wavelength range of ~ 1 nm for exposure,
When pattern transfer is performed, it is possible to use a thinned absorber that can be easily microprocessed.

Further, by selecting the material of the absorber as in claims 3 to 8, the respective phases φ ₁ and φ ₂ of the X-ray transmitted through the absorber and the mask portion (or transmitted through the absorber and the transmission film). The difference | φ ₁ −φ ₂ | (or | φ _a −φ _t |) of the shift amount of each phase φ _a and φ _t ) of the obtained X-ray becomes substantially constant over the exposure wavelength band, and the synchrotron radiation X-ray transfer having a suitable phase shift effect on light can be performed to improve pattern resolution. In particular, in exposure using synchrotron radiation having an exposure wavelength of 0.6 to 1 nm, which has excellent resolution, a significant improvement in pattern resolution can be expected.

[0065]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments.

(First Embodiment) As shown in FIG.
The X-ray exposure mask 1 has a configuration in which an X-ray absorber pattern 5 is formed on a membrane 6 as an X-ray transmitting thin film, and the periphery of the membrane 6 is supported by a support 7. The basic configuration of the mask is the same as that of the conventional mask, but in the present embodiment, as will be described later, the constituent materials, particularly the absorber material, are significantly different from those of the conventional mask.

As the X-rays 4, synchrotron radiation was used. The synchrotron radiation light includes ring-stored electron energy of 600 MeV, deflection magnetic field of 3 T, maximum storage current of 500 mA, maximum exposure area of 30 mm square, and maximum exposure intensity of 5 mm.
Those having 0 mW / cm ² and a beam parallelism of ² mrad or less were used. As a window for extracting the emitted light, a beryllium (Be) window having an average film thickness of 25 μm, a silicon nitride (Si ₃ N ₄ ) window having an average film thickness of 1.5 μm, and a diamond window having an average film thickness of 1.0 μm were used. An incident-type platinum (Pt) mirror was used for the light and the oscillating mirror. At this time, synchrotron radiation light having a wavelength range of 0.62 to 1.02 nm is obtained, and a 1.0 μm-thick membrane material, silicon nitride (Si ₃ N ₄ ) film, silicon carbide (SiC) film The intensity distribution of the radiated light after transmission of each of the diamond film and the silicon (Si) film is as shown in FIG. 5, which is an exposure light source suitable for improving the pattern accuracy of the object to be exposed. here,
As a resist material, a novolak resin-based chemically amplified negative resist (thickness d _R = 0.3 μm) was used.

The membrane 6 has a thickness of 1 μm or 2 μm.
m silicon nitride (Si ₃ N ₄ ) film, silicon carbide (SiC)
A film, a diamond film, a silicon (Si) film, or an X-ray exposure mask having the structure shown in FIG. 1 in which the absorber da has _a thickness da of 0.4 μm was used under the above exposure conditions. The results of mask contrast of various materials that are sometimes obtained are shown in the following (Table 1).

[0069]

[Table 1]

As apparent from Table 1, Gd,
Tb, Sm, Ho, Ir, Pt, Dy, and Os are simple elements that have higher absorption and higher mask contrast than conventional materials of Au, W, and Ta, and have a wavelength range of 0.6 to 1 nm.
It is found that the material is a suitable absorber material for X-ray exposure using synchrotron radiation. In addition, Tm, E
When r, Pm, Cu, Nd, and Ni are used, a higher mask contrast is obtained than Ta, which indicates that these are suitable absorber materials.

In this embodiment, the wavelength range is 0.6 to 1n.
Absorber materials of simple elements that have high absorption and high mask contrast in X-ray exposure using synchrotron radiation of m are divided into the following three groups based on the relationship between the atomic number density and the position of the absorption edge wavelength. Revealed that

1) Atomic numbers 27 to 31 → Co (27) to Ga (31) 2) Atomic numbers 57 to 71 → La (57) to Lu (71) 3) Atomic numbers 72 to 80 → Hf (72) to Below Hg (80), the elemental elements in these groups have a wavelength range of 0.6 to 1
The reason why the absorption is large and the high mask contrast is obtained in the X-ray exposure using the synchrotron radiation of nm is described.

The complex refractive index of the substance in the soft X-ray region and
The absorption and extinction coefficients are expressed by the following equations (1) to (4).
Is the atomic number density N as shown in equation (4)._aAnd atomic scattering factors
Child f _TwoIs proportional to the product of
The size is also the atomic number density N_aAnd the atomic scattering factor f_TwoDepends on
You.

[0074] n-ik = 1-δ- iβ = 1- (N a r e λ 2 / 2π) (f 1 + if 2) ... (1) δ = N a r e λ 2 f 1 / 2π ... (2 _{) k = = β = N a} r e λ 2 f 2 / 2π ... (3) α = 4πk / λ 2N a r e λf 2 ... (4) where, N _a: atomic number density r _e: classical electron radius (2.81794 × 10 ^-15 [m]) λ: X-ray wavelength f ₁ , f ₂ : Real part and imaginary part of atomic scattering factor n: Refractive index α: (Line) absorption coefficient [cm ^-1 ] k: Extinction Is the coefficient.

[0075] atom number density N _a is the density / atomic weight (D /
M), and D / M is 0.085 g / c as a single element.
The high-density elements of m ³ ] or more are the following elements.

A) Atomic numbers 22 to 31 (Ti-Ga) (4.54-
8.93 g / cm ³ ) D / M = 0.085-0.151 B) Atomic number 41-47 (Nb-Ag) (8.56-12.44 g / cm ³ )
D / M = 0.092-0.1 C) Atomic number 73-79 (Ta-Au) (16.65-22.57 g / cm ³ )
D / M = 0.092-0.119 On the other hand, the atomic scattering factor f ₂ changes with respect to the wavelength, and the change is particularly large near the absorption edge, and the atomic scattering factor f ₂ becomes large near the shorter wavelength side than the absorption edge wavelength, It becomes extremely small near the long wavelength side. Therefore, when using a synchrotron radiation source, the absorption and the mask contrast greatly depend on the position of the absorption edge wavelength of the element, because the absorption is over the entire wavelength range of the emitted light. The above exposure conditions (exposure light,
Window material, membrane material) wavelength range 0.6-1nm
In the X-ray exposure using synchrotron radiation, the following simple elements whose absorption edge wavelengths are present at wavelengths of 0.75 to 1.6 nm near the longer wavelength side of the radiation light wavelength region are the atomic scattering factors f ₂ is increased.

D) Atomic numbers 27 to 35 (Co-Br) L-shell absorption edge 0.75 to 1.6 nm E) Atomic numbers 56 to 71 (Ba-Lu) M-shell absorption edge 0.75
Elements belonging to groups A) and D), that is, elements having a density / atomic weight of 0.085 [g / cm ³ ] or more and having an L-shell absorption edge at a wavelength of 0.75 to 1.6 nm are atoms Number 27-3
0, Co, Ni, Cu, Zn, and Ga, the L-shell absorption edge of which is at λ = 1 to 1.6 nm, which is on the long wavelength side with respect to the wavelength range of synchrotron radiation (0.6 to 1 nm). The atomic scattering factor f ₂ is large and the atomic number density N
_{a is} also high. For this reason, the absorptance increases, and the mask contrast becomes 2.5 or more at the absorber thickness of 0.4 μm. Therefore, Co, Ni, Cu, Zn have a wavelength range of 0.6.
It is the most suitable absorber material for X-ray exposure using synchrotron radiation of １1 nm.

Similarly, when the M shell absorption edge is λ = 0.7 to 1.5
lanthanide elements La, Ce, Pr, atomic numbers 57-71, excluding Ba of group E)
Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, T
Also in m, Yb, and Lu, since the M-shell absorption edge is near the long wavelength side with respect to the wavelength region of synchrotron radiation, the atom scattering factor f ₂ becomes large, and the element has a low atomic number density. However, the absorptance increases, and the mask contrast becomes 2.5 or more at an absorber film thickness of 0.4 μm for elements having a density / atomic weight of 0.040 [g / cm ³ ] or more. Ba has a density / atomic weight of 0.025 [g / cm].
For ^3] and extremely low atomic number density N _a low, not absorptance mask contrast is also high.

Accordingly, atomic numbers 57 to 7 of group E)
La to Lu of No. 1 are also suitable absorber materials in X-ray exposure using synchrotron radiation having a wavelength range of 0.6 to 1 nm. In particular, Gd, Tb, Sm, and Ho have a wavelength range of 0.1.
Absorption at 6-1 nm is Ir, Pt, Au, W, Ta
It is the preferred absorber material because it provides the largest absorption and mask contrast among the single elements (excluding uranium).

[0080] It An element Nb~Ag of atomic number 41 to 47 of Group B) In contrast, although the high atomic number density N _a, in its L-shell absorption edge λ = 2.5~0.5nm exist, atomic scattering factors f ₂ because of the wavelength region of light to the long wavelength side of the absorption edge becomes small, the value of the mask contrast is not so large.

Further, a high-density material conventionally used as an absorber material having an atomic number of 73 to 79 in Group C),
Ta, W, Au (16.65, 19.30, 19.32 g / cm ³ )
The M4 and M5 absorption edges are located at wavelengths of 0.4 to 0.7 nm, and the absorption sharply decreases when the wavelength is longer than the absorption edge. Lower. In particular, Ta and W have absorption edges of Si.
Since the K absorption edge is near 0.6738 nm and the absorption is superimposed, when a Si-based material is used for the membrane material and the window material, light having a wavelength of 0.6738 nm or less is absorbed (attenuated) by the membrane to increase the mask contrast. , The absorption and mask contrast values are lower than those of Ir, Pt, and Au in the same group.

As described above, a single element which can provide a high mask contrast in X-ray exposure using synchrotron radiation having a wavelength range of 0.6 to 1 nm is obtained from the relationship between the atomic number density and the position of the absorption edge wavelength. 2) Atomic numbers 57-71 La (57) -Lu (71) 3) Atomic numbers 72-80 3) Atomic numbers 72-80 Hf (72) -Hg (80) Can be divided into two groups.

FIG. 9 shows the absorption characteristics of the elements belonging to groups 1) to 3), Cu, Gd, Ta, W and Au. Cu has a lower density than Ta and W, but has _a high atomic number density Na, and has a beam wavelength region near the short wavelength side of its L absorption edge, so that the atomic scattering factor f ₂ becomes large and the absorption becomes Ta. , W at a wavelength of 0.7 nm or more, and a higher mask contrast is obtained. Gd also atomic scattering factor f ₂ because there is a wavelength range of the beam on the short wavelength side near the M absorption edge increases, the absorption rate, the mask contrast it is apparent that higher.

The film thicknesses required for setting the mask contrast to 10 in the above main elements are shown in Table 2 below.
Shown in

[0085]

[Table 2]

As is clear from Table 2, Cu,
Sm, Gd, and Tb have a greater X-ray absorption than Ta and W, and can be made thinner. In particular, S
m, Gd, and Tb absorb more than Au and can be made thinner. Other elements such as Ho and Tm also absorb more than Au.

In the transfer of a fine pattern having a line width of 0.2 μm or less, the ratio (aspect ratio) of the film thickness of the absorber for sufficiently shielding X-rays to the pattern line width is increased. Although it is difficult to form an absorber pattern with high accuracy by using an absorber material or a mask making method, if the absorber selected according to the present embodiment is used, the absorption is large for X-rays used for exposure, and the thickness is reduced. And fine processing is facilitated.

(Second Embodiment) In the first embodiment, by combining elements used alone, it is possible to further improve the absorption characteristics of the absorber material. That is, the absorption edge of the L-shell is set to an exposure wavelength range of 0.6 to 1 n as an absorber.
any one of the elements of atomic numbers 27 to 31 (Co to Ga) 1) having a longer wavelength (0.75 to 1.6 nm) than m and an M-shell absorption edge having an exposure wavelength range of 0.6 to Atomic number 7 having a wavelength shorter than 1 nm (0.5 to 0.75 nm)
An alloy or a laminated film in which any one of the elements in the group 3) of 2 to 80 (Hf to Hg) is combined has a wavelength range of 0.6 to 1 (Hf to Hg).
It is a suitable absorber material because it has a large absorption for synchrotron radiation of nm and can provide a high mask contrast without increasing the thickness of the absorber.

Similarly, the M shell absorption edge is set to an exposure wavelength range of 0.6 to
Lanthanoid rare earth elements (La) having atomic numbers 57 to 71 having a wavelength longer than 1 nm (0.75 to 1.6 nm)
To Lu) and any one of the elements in group 2), and the M-shell absorption edge is set to a wavelength shorter than the exposure wavelength range of 0.6 to 1 nm (0.5 to 0.5 nm).
Atomic numbers 72 to 80 (Hf to H) at 0.75 nm)
An alloy or a laminated film in which any one of the elements in group 3) of g) is combined has a large absorption for synchrotron radiation in a wavelength range of 0.6 to 1 nm, and the thickness of the absorber is not increased. Is a material that can provide a high mask contrast, and is a suitable absorber material.

In particular, Sm, G of the simple elements of group 2)
d, Tb, Dy, Ho and I of the simple element of group 3)
The combination with r, Pt, and Au is a suitable material as a constituent element of the compound because the mask contrast of each element is high. For example, in the combination of Au and Sm, Sm absorbs more than Au (film thickness 0.4
μm, mask contrast Sm: 4.73 to 4.94;
Au: 4.29 to 4.50), it is possible to very high mask contrast by its absorption characteristics change _{(Sm 3 Au 2: 5.78~6.10)} . 2
The density of the original compound is integrated according to the composition ratio from the density of each elemental element according to the composition ratio, and the calculation result of the mask contrast of the alloy and compound when the absorber film thickness is 0.4 μm and the membrane thickness is 1 μm is as follows. (Table 3).

[0091]

[Table 3]

The values of the mask contrast of the alloys and compounds in Table 3 are higher than those of any single element, and a very large mask contrast is obtained as compared with the single element. Figure 10 shows the change in absorption characteristics and the mask contrast when changing the composition of Gd _1-x Au _x, it can be seen that the improved mask contrast depending on the change in absorption characteristics.

In compounds of combinations other than those shown in Table 3, in Ta (73), 1) elements of atomic numbers 30 to 33 Zn (30) to As (33) 2) atomic numbers 56 to 72 3) In the binary compound of elements Ba (56) to Hf (72) 3) elements Re (75) to Bi (83) with atomic number 75 or higher, the mask contrast becomes higher than any of the constituent elements.

Similarly, for W (74), 1) the elements Ge (32), As (33) with atomic numbers 32 and 33 2) the elements Ba (56) to Hf (72) with atomic numbers 56 to 72 3) Elements with atomic numbers from 75 to 79 Even in a binary compound with Re (75) to Au (79), the mask contrast becomes higher than any of the elements.

In Re (75) and Os (76), the elements Ba (56) to Au (79) Ir (77) having the atomic numbers 56 to 79 have the atomic numbers 56 to 78. The elements Ba (56) to Pt (78) Pt (78) and Au (79) have high mask contrast and high binary contrast with the elements Ba (56) to Ir (77) with atomic numbers 56 to 77. Become. Therefore, these alloys and compounds are effective substances for reducing the thickness of the absorber and are suitable absorber materials.

The following Table 4 shows the film thicknesses necessary for setting the mask contrast to 10 in the absorbers of the above main alloys and compounds.

[0097]

[Table 4]

As is clear from Table 4, the alloy,
In the compound, the absorption is larger than any single element, and a thinner film can be obtained. In Table 3, substances Gd ₁₁ Ir ₉ and Gd ₃ A having a mask contrast of 6.50 or more are shown.
The required film thickness of u ₂ , Gd ₁₁ Pt _9, etc. is 500 nm
The film thickness can be greatly reduced as follows. Therefore, when the alloy or compound material proposed by the present embodiment is used for the absorber, the absorption is large for the exposure light in the wavelength range of 0.6 to 1 nm, and the absorber material can be made thinner, and the mask can be manufactured. The microfabrication in becomes easy.

(Third Embodiment) Next, the difference | φ ₁ −φ ₂ | between the shift amounts of the phases φ ₁ and φ ₂ of the X-ray transmitted through the absorber and the mask substrate is determined by the resolution. Proposal of a phase shift mask suitable for synchrotron radiation using an absorber material which is constant over the wavelength band in exposure in an excellent exposure wavelength range of 0.6 to 1 nm, and at the same time also provides a high mask contrast, and An embodiment of an X-ray exposure method using a mask will be described below.

First, in exposure to synchrotron radiation in an exposure wavelength range of 0.6 to 1 nm, the difference | φ ₁ − between the phase φ ₁ and the phase φ ₂ of the X-ray transmitted through the absorber and the mask substrate. A preferred absorber material in which φ ₂ | does not significantly change with wavelength will be described.

The preferred wavelength range of the synchrotron radiation is 0.6 to 1 nm, and the wavelength range of the synchrotron radiation used in the embodiment is also 0.62 to 1.02 nm.
Which is a suitable exposure light source. However, in the exposure using the synchrotron radiation as a light source, a Be window (average film thickness: 25 μm), a Si ₃ N ₄ window (average film thickness: 1.5 μm), and a diamond window (average film thickness: 1.0 μm) are used as extraction windows. ) Is used, and the wavelength range from the maximum intensity to 1/10 of the intensity spectrum in the intensity spectrum after passing through those materials is 0.654 to 1.015 nm.
Since Si has its absorption edge at a wavelength of 0.674 nm,
Under ordinary exposure conditions using a Si-based material for a window material or a membrane material, exposure light having a wavelength of 0.674 nm or less is absorbed and attenuated. Therefore, the wavelength region contributing to the exposure is 0.6 here because it does not significantly affect the exposure.
It is 54 to 1.015 nm, and it is desired that the absorber material is suitable in this effective wavelength range.

The following (Table 5) shows a wavelength range of 0.654.
Shows average amount of phase shift of the absorber in ~1.015nm is at the time of setting the film thickness d _a such that [pi, the dispersion result of the phase shift amounts of the various single element as [Delta] [phi ([Delta] [phi: Phase Displacement of the shift amount from π).

[0103]

[Table 5]

Table 5 also shows the mask contrast obtained for each membrane material at a wavelength at the absorption edge of each element and a film thickness of 0.4 μm. In this (Table 5), it can be seen that there is a large difference in the phase characteristics between the element including the absorption edge and the element not including the absorption edge within the beam wavelength range, and the dispersion of the phase shift amount is small in the element not including the absorption edge.

FIG. 11 and Table 6 below show the phase change characteristics of typical absorbers of the element including the absorption edge and the element not including the absorption edge within the beam wavelength range.
The phases of a and W greatly change, and it is difficult to change the phase by π over the entire wavelength range of the light beam.
It can be seen that the phase change of elements that do not include the absorption edges of u, Cu, Ni, Zn, and Cu—SiO ₂ (embedding Cu in the SiO ₂ film) is small with respect to the wavelength and can be substantially controlled.

[0106]

[Table 6]

An element that does not include an absorption edge in the wavelength range does not have a sharp change in the refractive index in the wavelength range, so that the film thickness for π phase shift and the change with respect to wavelength are small, and the phase can be controlled. Therefore, it is suitable as an absorber material for a phase shift mask. In X-ray exposure, the wavelength range is 0.
When an X-ray source existing at 6-1 nm is used, 1) Group I atomic numbers 27-31 Co (27) -Ga (31) 2) Group II atomic numbers 41-52 Nb (41) -Te (52) 3) Group III atomic numbers 57 to 63 La (57) to Eu (63) 4) Group IV atomic numbers 76 to 92 Os (76) to U (92) It is a substance that is not included in the region and that can be easily subjected to phase shift control. In order to make it possible to control any desired phase difference by changing the film thickness, an X-ray exposure mask having a phase shift effect is absorbed. It is a suitable material for the body material. Also,
Among these materials, those which are also included in the materials having high absorption shown in the first embodiment include Co (27) to Ga (31) having atomic numbers 27 to 31 and La (57) having atomic numbers 57 to 63. ) To Eu (63) Os (76) to Hg (80) having atomic numbers of 76 to 80, and these substances exhibit phase characteristics in X-ray exposure using synchrotron radiation having a wavelength range of 0.6 to 1 nm. And it is a very suitable absorber material excellent in both of the absorption characteristics. Other elemental elements Fr (87), atomic number 89-
Ac (89) to U (92) of No. 92 are also excellent in phase characteristics and absorption characteristics, but they are rare, difficult to obtain, and expensive, and are not practical. are doing.

Next, an absorber material which is excellent in the controllability of the above-mentioned phase shift amount and is suitable for the absorber material of the phase shift mask will be described below.

As a simple element which is difficult to control over the entire band in a synchrotron radiation light source having a wavelength range of 0.6 to 1 nm, the following elements containing an absorption edge in a wavelength range of 0.654 to 1.015 nm are as follows: 1) Atomic number 12-14 Mg (12) -Si (14) K-shell absorption edge 2) Atomic number 32-37 Ge (32) -Rb (37) L-shell absorption edge 3) Atomic number 64-75 Gd (64 ) To Re (75) M shell absorption edge. This is because a sharp change in the refractive index occurs at the absorption edge wavelength, and the film thickness for π-phase shift also greatly changes with the wavelength. Representative absorber materials for X-ray exposure, Ta (73) and W (74) are included in these, Ta (tantalum: atomic number 73), M-shell absorption edge wavelength: M4: 0.687 nm, M5: 0.711 nm π phase absorber film thickness: d _a = 679.50 nm (mask contrast: 7.20 to 7.55) π phase shift amount: | φ ₁ −φ ₂ | ≦ π ± 0.54π (wavelength
0.654 to 1.015 nm) W (tungsten: atomic number 74) M-shell absorption edge wavelength: M4: 0.659 nm, M5: 0.6
83 nm π phase absorber film thickness: d _a = 581.70 nm (mask contrast: 6.77 to 7.08) π phase shift amount: | φ ₁ -φ ₂ | ≦ π ± 0.56π (wavelength 0.65
The phase changes by π / 2 or more within this wavelength range, and the phase of these substances can be controlled by film thickness when exposed to a light source using characteristic X-rays. It is difficult to control a radiation light source over the entire wavelength range.

On the other hand, since an element which does not include an absorption edge in the wavelength region does not have a sharp change in the refractive index in the wavelength region, the film thickness for the π phase shift and the change with respect to the wavelength are small, and the phase can be controlled. . In X-ray exposure, when an X-ray source having a wavelength range of 0.6 to 1 nm is used, Co (27) to Ga (31) of Group I and Nb (4
1) to Te (52), La (57) to Eu (63) of Group III, and Os (76) to U (92) of Group IV.

Next, the individual elements of these four groups will be described individually, including their absorption characteristics.

1) Group I (atomic numbers 27 to 31: Co
(27) to Ga (31)) The elements of this group have a density of 5.90 to 8.93.
g / cm ³ , which is lower than that of a conventionally used absorber material, but has _a higher atomic number density Na, and the absorption edge of the L shell has λ = 1.
Present in ～1.6Nm, atomic scattering factor f ₂ because of the wavelength region of synchrotron radiation in the short wavelength side near the absorption edge increases, also increases the value of the absorption α and the mask contrast. Π in a wavelength range of 0.654 to 1.015 nm
The change of the phase shift of this group when the phase shift film thickness d _a, shown in Figure 12 and the following (Table 7).

[0113]

[Table 7]

The displacement of the phase shift amount from π is Δφ =
0.07 to 0.18π, and the elements in this group can control the amount of phase shift in exposure in this wavelength range.
In particular, Cu, Zn, and Ga have a phase shift of π ± 0.13.
π, π ± 0.10π, π ± 0.07π, and it is possible to precisely control any desired phase difference by changing the film thickness, and the mask contrast is high. It is a suitable absorber material in the exposure wavelength range.

2) Group II (atomic numbers 41 to 52: N
b (41) to Te (52)) The Nb (41) to Te (52) elements of this group have an L-shell absorption edge at λ = 0.25 to 0.50 nm and have a longer wavelength at the absorption edge. Has a wavelength range of synchrotron radiation, the atomic scattering factor f ₂ also decreases, and the values of absorption α and mask contrast also decrease. Wavelength range 0.654 to 1.01
A change in the phase shift elements in this group when the film thickness d _a of 5 nm, 13 and below (Table 8).

[0116]

[Table 8]

The displacement of the phase shift amount from π is Δφ = 0.
18 to 0.24π, the displacement is large and the mask contrast is low as compared with the group I substances. However, the Ru (44), R
h (45) and Pd (46) have relatively high densities (12.06-
12.44 g / cm ³ ), and the film thickness required for π phase shift can be extremely thin, 474.14 to 487.46 nm. Therefore, these elements have high absorption and are suitable absorber materials.

3) Group III (atomic numbers 57 to 63:
La (57) to Eu (63)) The La (57) to Eu (63) elements all belong to rare earth elements,
Its density is as low as 5.24 to 7.52 g / cm ³ , but its absorption edge (M shell in this case) is λ =
Since the wavelength is within 1.1 to 1.5 nm and the wavelength region of synchrotron radiation is on the short wavelength side of the absorption edge, the atomic scattering factor f ₂
Increases, and the values of the absorption α and the mask contrast also increase. Further, as the atomic number increases, the wavelength of the M-shell absorption edge becomes shorter, the absorption edges of Gd to Tm of atomic numbers 64 to 69 overlap with the wavelength range of synchrotron radiation, and the absorption and mask contrast values become extremely large. .

Since the density is low, the change in the refractive index with respect to the film thickness is small, and the film thickness for π phase shift is 985.8.
8 to 1611.3 nm, but the amount of displacement of the phase shift from π is | Δφ | = 0.03 to
0.14π is excellent in phase controllability, it is possible to precisely control any desired phase difference by changing the film thickness, and La (57) ~
The Eu (63) element is a suitable material for the absorber of the phase shift mask (see FIG. 14 and (Table 9)).

[0120]

[Table 9]

4) Group IV (atomic numbers 76 to 92: Os)
(76) to U (92)) The Os (76) to Au (79) elements in this group have very high densities of 19.32 to 22.57 g / cm ^3, and also have values of absorption α and mask contrast. growing. However, the absorption edge of the M shell is present in λ = 0.3~0.6nm, atomic scattering factor f ₂ because of the maximum light intensity wavelength of synchrotron radiation in the long wavelength side of the absorption edge of the absorption edge The absorption in the wavelength range does not differ significantly from that of Cu of Group I because it is lower than at short wavelengths and near.

[0122] Since the density is high, large refractive index change with respect to the film thickness, the thickness d _a of the order to π phase shift 40
It can be as thin as 3.70 to 441.03 nm.
The change of the phase shift of this group when the film thickness d _a of the wavelength region 0.654～1.015Nm, 15
And (Table 10) below.

[0123]

[Table 10]

The displacement of the phase shift amount from π is Δφ = 0.
12 to 0.36π. Pt and Au used for the absorber material are Δφ = 0.27 and 0.25π, respectively, and the displacement amount is large as compared with the group I elements.
It is difficult to accurately control the desired phase difference by changing the film thickness (see FIG. 15).

The results of the simple elements belonging to the four groups I to IV are summarized in (Table 11).

[0126]

[Table 11]

Here, the film thickness of the absorber required to shift the phase by π, the phase shift dispersion and the mask contrast obtained at that time (the values in the parentheses are the mask thickness when the membrane thickness is 1 μm and the absorber film thickness is 0.4 μm). Contrast value).

Among the preferred elements shown in Table 11, in particular, the following two conditions 1) excellent controllability of the amount of phase shift (Δφ = 0.20)
π).

2) High mask contrast (2.80 or more when absorber thickness is 0.4 μm).

The elemental elements satisfying the conditions are Co, Ni, Cu of Group I, Rh, Pd of Zn Group II, La, Ce, Pr, Nd, Pm, Sm, E of Ag Group III.
u Group IV At, Rn, Fr, Ac, Th, Pa, U. Therefore, these simple elements are suitable absorber materials for improving the resolution of the transfer pattern by utilizing the phase shift effect.

Further, among these simple elements, the conditions desired for an absorber material of a phase shift mask having excellent controllability of the amount of phase shift, a small thickness of the absorber and a suitable mask contrast value are as follows. Conditions, 1) Δφ ≦ 0.125π (0.92 ≦ | cosφ | ≦
1) The maximum and minimum phase shift amounts with respect to wavelengths within the exposure wavelength range are ±± the average phase shift amount within the exposure wavelength range.
Within 12.5%.

2) When the mask contrast value C at the π phase shift film thickness is about 10 3) When the π phase shift film thickness d _a ≦ 1000 nm (the aspect ratio is 10 or less at a line and space pattern width of 0.1 μm), the exposure wavelength range 0.65-1.
For X-ray exposure at 02 nm, a suitable absorber material that satisfies all these conditions is Cu (copper: atomic number 29) π Phase absorber film thickness: d _a = 612.40 nm (mask contrast: 7.19 to 7.77) π Phase shift amount: | φ ₁ -φ ₂ | ≦ π ± 0.125π Zn (zinc: atomic number 30) π phase absorber film thickness: d _a = 790.25 nm (mask contrast: 9.36 to 10.23) π phase shift amount: | Φ ₁ -φ ₂ | ≦ π ± 0.10π. Therefore, Cu and Zn have an exposure wavelength range of 0.6 to 1 n.
It was shown to be a simple element having optimal absorption and phase characteristics for X-ray exposure using m synchrotron radiation.

Here, for synchrotron radiation in the wavelength range of 0.6 to 1 nm, Cu and Zn have excellent absorption characteristics and phase characteristics and are suitable as an absorber material for an X-ray exposure mask. Was done. However, JP-A-5-13309
When these materials are used for synchrotron radiation having a wavelength range of 1 to 1.5 nm as proposed in the above publication, these materials have their absorption edges in or near this wavelength range. Therefore, as shown in FIG. 16, the amount of phase shift greatly changes with wavelength. Therefore, it is difficult to control the amount of phase shift, and it cannot be expected that a sufficient phase shift effect is obtained.

The following Table 12 shows the phase shift amount, the displacement from the average phase shift amount, and the ratio of the displacement in the wavelength range of 1 to 1.5 nm of each absorber.

[0135]

[Table 12]

Therefore, in exposure with synchrotron radiation having an exposure wavelength range of 1 to 1.5 nm,
When an X-ray exposure mask using Co, Ni, Cu, and Zn as absorbers is used, the absorption of X-rays in this wavelength range is large, but phase control is difficult, and the resolution of the transfer pattern is 0. Exposure using synchrotron radiation having an exposure wavelength range of 6 to 1 nm is higher.

(Fourth Embodiment) Group II (atomic numbers 41 to 52: Nb to Te) having an absorption edge on the short wavelength side of exposure light in the short wavelength range of 0.6 to 1 nm of 0.2 to 0.6 nm; IV
The phase characteristics of the elemental elements (atomic numbers 76 to 92: Os to U) are as follows: Group I (atomic numbers 27 to 92) having an absorption edge in the wavelength region of exposure light of 0.6 to 1 nm on the long wavelength side of 1 to 1.6 nm. 3
1: Co to Ga) and III (atomic numbers 57 to 63: La)
The phase characteristics can be improved by using alloys and compounds in combination with the elements (Eu) to (Eu). At this time, there is a combination that can greatly improve not only the phase characteristic but also the absorption characteristic as described in the second embodiment.

Hereinafter, in this embodiment, Group II and Group II
The fact that phase characteristics are improved in alloys and compounds in which the element IV and the elements of groups I and III are combined will be described.

The phase shift amount of the simple element has a characteristic of increasing rightward on the long wavelength side except that it sharply decreases at the position of the absorption edge. Since all elements of Groups I to IV do not have absorption edges within the exposure wavelength range,
Many substances have a large amount of phase shift on the long wavelength side.

The elements of Groups I and III have L and M shell absorption edges in the vicinity of the long wavelength region of the exposure wavelength at 1 to 1.6 nm. At this absorption edge wavelength, the amount of phase shift is small. In the wavelength region near the shorter wavelength side than the end wavelength, the change in the phase shift amount with respect to the wavelength is small, so that the phase dispersion is small in the exposure wavelength region of 0.654 to 1.015 nm. On the other hand, the elements of groups II and IV have absorption edges of 0.25 to 0.6 n on the shorter wavelength side of the exposure wavelength.
m, the change of the phase shift amount with respect to the wavelength is larger than that of the elements of Groups I and III.

Accordingly, the simple elements of Groups I and III are suitable absorber materials for controlling the amount of phase shift.
Alloys and compounds in which these elements are combined with the elements of Groups II and IV can improve the phase characteristics. In particular, Zn and Ga of Group I and Pm, Sm and Eu of Group III have absorption edges at 1.1 to 1.2 nm near the long wavelength region of the exposure light, and the phase changes near 1 nm near the absorption edge. It is a suitable material because the amount of phase shift is small in the long wavelength region of the exposure light. Group I Zn, Ga, Group III
Pm, Sm, and Eu are the exposures of the phase shift amount by alloying / compounding all the elements of Groups I to IV, which increase the phase shift amount in the long wavelength region of the exposure light, with these substances. These combinations are preferable because the change with respect to the wavelength within the wavelength range can be reduced. In particular, in the simple elements of groups II and IV having poor phase controllability, the phase displacement in the π phase shift is | φ ₁ −φ ₂ | ≦ π ± 0.2
0 to 0.30π, the elements of Group I and Group II
By combining the elements of I, the characteristics can be greatly improved.

For example, the element Au of group IV and the group Au
Sm combining element Sm of III _FourAu alloy smell
The amount of π phase shift is | φ₁−φ_Two| ≦ π ± 0.04π
Can be controlled. Also, Sm_xAu_yIn alloys,
The screen contrast is higher than the value of any single element
Can be done. Au shifts the phase by π.
Film thickness d_aIs as thin as 441.03 nm and the mask
Synchrotron radiation in this wavelength range due to high trust
High resolution using phase shift in light exposure
Is a suitable substance for obtaining
Keeping the phase displacement low makes the material more effective. This
The same is true for the other elements of Group IV.
Os, Pt, and Ir are preferred because they absorb more than Au.
It is a suitable material.

Therefore, the absorption edge is shifted to the short wavelength side (0.25 to 0.25).
In order to change the phase characteristics of the single elements of groups II and IV having a wavelength of 0.60 nm), it is effective to use compounds and compounds of these substances because groups I and III have an absorption edge of 1 to 1.6 nm. is there. Also, the mask contrast can be made higher than the value of any single element by changing the absorption characteristics.

FIG. 17 and the following (Table 13) show that Sm _x
When the composition of the Au _y binary alloy is changed, (a) the phase shift amount and (b) the mask contrast (absorber film thickness 0.4 μm)
m). The mask contrast is Sm
The composition ratio of ₃ Au ₂ becomes the maximum, and the phase shift control at this time can be very accurately controlled to π ± 0.09π at a film thickness of about 700 nm, which is suitable as an absorber material.

[0145]

[Table 13]

In addition to the combination of Group III and Group IV, the mask contrast and phase characteristics are also improved in the combination of Group I and Group III, Group I and Group II, and Group II and Group III.

The following (Table 14) shows the phase characteristics when the main alloys and compounds of the combinations of Group I and Group III and Group III and Group IV are used as the absorber material (the format is the same as in Table 11). And the mask contrast value.

[0148]

[Table 14]

According to Tables 13 and 14 and FIG.
It is possible to change the mask contrast and the controllability of the amount of phase shift by changing the composition ratio of the compound, and by optimizing the composition ratio with a combination of materials proposed in the present embodiment, an arbitrary film can be formed. It is apparent that the desired mask contrast and phase shift amount can be accurately controlled by the thickness.

Accordingly, the atomic numbers 27 to 31 of group I
Co (27) -Ga (31) and group III atomic number 57-
Alloys and compounds combining La (57) to Eu (63) of 63, and La (57) of Group III atomic numbers 57 to 63
Eu (63) and Os (7
Alloys combining 6) to U (92), Rh (45) to Ag (47) having atomic numbers 45 to 47 of Group II and Co (27) to Ga (31) of Group I 27 to 31; An alloy combining La (57) to Eu (63) with atomic numbers 57 to 63 of Group III is a material suitable for an absorber of a phase shift mask using synchrotron radiation having a wavelength range of 0.6 to 1 nm. is there.

Among these alloys and compounds, the following three conditions desired for an absorber material of a phase shift mask having excellent controllability of the amount of phase shift, a small thickness of the absorber, and an appropriate value of the mask contrast are as follows: 1) Δφ ≦ 0.10π (0.95 ≦ | cosφ | ≦ 1) 2) Mask contrast value C at π phase shift film thickness
3) Assuming that the π phase shift film thickness d _a ≦ 850 nm, a suitable absorber material satisfying all of these conditions is a SmNi ₄ π phase absorber film thickness: d obtained by combining groups I and III. _a = _702.03nm (mask contrast: from 11.01 to 12.01) [pi phase _{shift: | φ 1 -φ 2 | ≦} π ± 0.10π Nd 2 Cu 3 π phase absorber film thickness: d _a = 813 .14Nm (mask contrast: from 14.97 to 16.52) [pi phase _{shift: | φ 1 -φ 2 | ≦} π ± 0.07π Nd 3 Cu 7 π phase absorber film thickness: d _a = 764.23nm ( mask contrast: 12.81 to 14.08) [pi phase shift: | φ ₁ -φ ₂ | and _{≦ π ± 0.08π, Nd 4 Au} π phase absorber film thickness by a combination of group III and IV: d _a = 837.64 nm (mask contra Strike: from 19.50 to 21.59) [pi phase _{shift: | φ 1 -φ 2 | ≦} π ± 0.08π GdAu π phase absorber film thickness: d _a = 661.88nm (mask Contrast: 19.14～ 20.94) π phase shift amount: | φ ₁ −φ ₂ | ≦ π ± 0.10π.

Further, an absorber material satisfying the three conditions can be obtained other than the above composition ratios and combinations. Therefore, it has been clarified that by optimizing the composition ratio with the combination of the materials proposed in the present invention, it is possible to accurately control the desired mask contrast and phase shift amount at an arbitrary film thickness. .

(Fifth Embodiment) In the third embodiment and the fourth embodiment, a description will be given of an absorber material suitable in a case where a permeable membrane substance does not exist in a groove between absorber patterns. In this embodiment, the mask for X-ray exposure shown in FIGS. 2 to 4 in which a transmission film having low absorption for X-rays is present on the membrane will be described. The transmissive film 8 on the membrane 6 has a small absorption with respect to the exposure wavelength, and includes, as a constituent element of the substance, an element having an absorption edge not included in the exposure wavelength range of the exposure light or an element having a short wavelength region near the exposure wavelength range. By using this, it is possible to control the dispersion of the amount of phase shift with respect to the wavelength of the absorber 5.

In the following, the invention of a method of controlling the amount of phase shift by using the transmission film in the present embodiment will be described.

In the mask for X-ray exposure shown in FIGS. 2 to 4, the phase of each of the X-rays transmitted through the absorber and the transmission film is defined as φ
when _a and _{Δφ t, | φ a -φ t} | in the exposure wavelength region, by selecting a material with a suitable phase characteristics phi _t to the phase phi _a having passed through the absorber, the wavelength band The phase controllability in exposure using a wide synchrotron radiation can be enhanced.

As for the absorber material, all the absorption edges have the shortest wavelengths in the exposure wavelength range (the wavelength range having an intensity of 1/10 or more of the maximum light intensity wavelength incident on the X-ray exposure mask). A single element compound or a laminated film made of an element having a region of less than or equal to or longer than the longest wavelength or in the vicinity of the longest wavelength (within 0.1 nm from the longest wavelength) is suitable. On the other hand, when the absorption edge is a substance made of an element included in the exposure wavelength range,
The phase characteristic greatly changes at and near the absorption edge wavelength, and it is difficult to reduce the phase dispersion in the exposure wavelength range, which is not suitable. The same can be said for a permeable membrane material, in which all absorption edges are composed of an element having an absorption edge near or below the shortest wavelength, or an element having an absorption edge near or below the shortest wavelength in the exposure wavelength range. element,
It is desirable to use a compound and a laminated film.

Here, the characteristics desired as the permeable membrane material are those satisfying the following conditions.

[0158] 1) It has a phase characteristic for canceling the phase dispersion of the absorbent material 2) small absorption for X-rays of the exposure light, the thickness D _t of a high transmittance material 3) permeable membrane is not too thick Condition 1) is to make the amount of phase shift for each wavelength of synchrotron radiation light having a wide wavelength band constant and suppress the phase dispersion. The phase shift amount of the element of the absorber that does not include the absorption edge in the exposure light wavelength range is small on the short wavelength side and large on the long wavelength side. Accordingly, the dispersion of the phase shift amount can be suppressed by using an element that does not include the absorption edge in the exposure light wavelength range or an element that has an absorption edge near the shortest wavelength in the exposure wavelength range. For an element having an absorption edge near the shortest wavelength, the refractive index n _t (λ _a ) and φ _t (λ _a ) sharply decrease at the absorption edge wavelength λ _a , and | φ _a (λ _a ) −φ _t (Λ _a ) | increases in the short wavelength range, so that the dispersion of the phase shift amount of the absorber can be suppressed. Here, an element having an absorption edge within 0.1 nm from the shortest wavelength is desirable.

The condition 2) is that if the absorption of the permeable membrane is large,
This is because the mask contrast obtained by the mask becomes low. In condition 3), when the transmission film needs to be thickened for phase shift, not only does the absorption of the transmission film increase to lower the mask contrast,
This is because the fine pattern formed on the permeable film has a structure with a high aspect ratio, and it is difficult to prepare the buried film and bury the absorber material or the permeable film material in the fine pattern grooves.
Condition 4) is a necessary condition when the reflow sputtering method is used to embed the absorber material into the permeable film fine pattern groove.

Here, the exposure wavelength range of 0.654 to 1.015 is the same as the exposure condition in the first embodiment.
When synchrotron radiation of nm is used, FIGS.
In the mask for X-ray exposure shown in FIG. 1, a permeable film material satisfying the above conditions is shown, and its effect will be described in detail below.

First, the wavelength λ transmitted through the absorber and the permeable film
When the phase difference | φ _a −φ _t | of each X-ray light becomes π, the film thicknesses _Da and D _t of the absorber and the transmission film are represented by the following equations.

[0162] _{| φ a -φ t | = 2π} | n a D a -n t D t | / λ = mπ ... (5) | n a D a -n t D t | = m (λ / 2) | δ _a (λ) D _a −δ _t (λ) D _t | = m (λ / 2) m = 0, ± 1, ± 2, ... (6) where φ _a : after transmission through the membrane / absorber phase shift phi _t: phase shift amount after the membrane permeable membrane permeability n _a, n _t: refractive index of the absorber and transmissive film _{δ a (λ), δ t} (λ): δ a (λ) = 1- n _a, δ _t
(Λ) = 1− _{ntD a} , D _t : film thickness of the absorber and the permeable film.

Here, the film thickness required to change the phase by π was determined for each of the various elemental elements, alloys and compounds, and the wavelength dispersion of the phase was examined. The wavelength range of the above synchrotron radiation light after passing through the membrane (1.0 μm thickness)
In the intensity spectrum, the wavelength range from the maximum intensity to the intensity of 1/10 was 0.654 to 1.015 nm. The phase shift average thickness π of the absorber and transmissive film at the exposure light wavelength band of the 0.654~1.015nm d _a, d _t
When the difference | φ _a −φ _t | between the phase shift amounts after transmission through the absorber and the transmission film having the thicknesses D _a and D _t is P, the following expression (7) is established.

D _a / d _a −D _t / d _t = P / π (7) where D _a and D _t are the thicknesses of the absorber and the transmission film, d _a is the π of the absorber in the exposure light wavelength region. phase shifting the average thickness d _t: [pi phase shift of the permeable membrane in the exposure wavelength region average thickness _{P: P = | φ a -φ} t | is the phase shift amount.

Therefore, the film thickness at the phase shift amount P is
When the thicknesses of the absorber and the permeable membrane are equal (see FIG. 2), _Da
= D _t (≡D), and this time the film thickness D is represented by formula (8), D = a · P / π ... (8) (d a d t / | | d t -d a). At this time, the phase dispersion in the exposure wavelength range is represented by the following equations (9) and (9 ′).

[0166] _{Δφ D = D · (Δφ a} / d a -Δφ t / d t) ... (9) Δφ D = (d a d t / | d t -d a |) · (P / π) · ( _{Δφ a / d a -Δφ t /} d t) = (P / π | d t -d a |) · (d t Δφ a -d a Δφ t) ... (9 ') also of the absorber and transmissive film when the film thickness is different from (D _a ≠ Dt) (see FIGS. 3 and _{4), Δφ D = Δφ a} D a / d a -Δφ t D t / d t ... (10) However, [Delta] [phi _a: absorption maximum displacement of the phase [pi in the body of the [pi phase shift average film thickness d _a Δφ _t: maximum displacement [Delta] [phi _D of the phase [pi in [pi phase shift average film thickness d _t of the permeable membrane: [pi phase shift average film thickness D Is the maximum displacement from the phase π at.

Here, the equations (9) and (10) indicate that the absorption edges of the elements constituting the absorber and the permeable membrane material are 0.654 to 1.0.
This holds only for substances that are not included in the exposure light wavelength band of 15 nm. In the present embodiment, when the film thickness of the absorber and the transmission film is equal (D _a = D _t (≡D)), the phase characteristics and the absorption characteristics of the combination of the various materials of the absorber and the transmission film are expressed by Equation (8). Using (9), the combination of the absorber material and the transmission film material suitable for the phase shift mask was examined.

First, the specific conditions 1 and 2 listed as characteristics desired as a material for the permeable membrane are as follows: 1) All the absorption edges of which are shorter than the shortest wavelength or longer than the longest wavelength in the exposure wavelength range. Element which is a region or an element having an absorption edge within 0.1 nm from the shortest wavelength (S
i: K 0.6738 nm and Rb: L3 0.6862
2) When a material having a small absorption and a film thickness _Dt of 400 nm and a decrease in light intensity of transmitted light of exposure light of 50% or less is used, characteristics of a single element satisfying these two conditions are shown in Table 15 below. ).

[0169]

[Table 15]

Therefore, Be, B, and
C, N, O, F, Na, Si, P, S, Cl, K, C
a, Sc, Ti, V, Cr, Rb, Sr, Y, Zr, N
b, Mo, I, and Ra are suitable as constituent elements of a permeable film material when synchrotron radiation having an exposure wavelength range between 0.65 nm and 1.02 nm is used as an exposure light source.

In Table 15, the melting points of various elemental elements, the π phase shift average film thickness d _t , the maximum displacement Δφ _t from the phase π in the film thickness, and the maximum displacement of the phase shift per unit thickness are shown. Δφ _t / _{dt is} shown.

Similarly, Table 16 shows the melting points and the π phase shift average film thickness d of various suitable single elements that do not have an absorption edge within the exposure wavelength range as the absorber material of the phase shift mask.
_a and the maximum displacement Δ from the phase π in the film thickness
φ _a , the maximum displacement of phase shift per unit thickness Δφ _a
/ Shows a d _a.

[0173]

[Table 16]

As an absorber material suitable for use as synchrotron radiation having an exposure wavelength range of 0.65 nm to 1.02 nm among the various elements listed in Table 16 as an exposure light source, this wavelength is It is an element that absorbs a large amount of X-rays in the region. Here, a substance having a transmittance of exposure light of 25% or less for an absorber film thickness of 400 nm is C.
o, Ni, Cu, Zn, Ga, Rh, Pd, Ag, L
a, Ce, Pr, Nd, Sm, Eu, Gd, Tb, D
y, Ho, Pt, and Au. Therefore, these single elements and alloys can increase the exposure wavelength range from 0.65 nm to 1.02 n.
It can be said that this is a suitable absorber material for an X-ray exposure mask having a transmission film on a membrane using synchrotron radiation light having a distance between m and m as an exposure light source.

Next, from the above-mentioned suitable substances as the absorber material of the mask for X-ray exposure with a transmission film, the following a) Au (Δφ _a = 0.25π, d _a = 441.0 n)
m) b) Cu (Δφ _a = 0.13π, d _a = 612.4n)
m) c) Ni (Δφ _a = 0.16π, d _a = 566.1n)
The results obtained by substituting the phase characteristics for each of the various permeable membranes when using m) into the equations (8) and (9) are shown in the following (Tables 17 to 19).

[0176]

[Table 17]

[0177]

[Table 18]

[0178]

[Table 19]

Next, the phase characteristics when the materials a) to c) are used as the absorber material will be described.

A) In the phase characteristics (Table 17) when the Au absorber is combined with the various elemental permeable films, the maximum displacement from π in the exposure wavelength range is shown as Δφ _D , and the elements are arranged in the order from the element having the lowest value. Are arranged. Au is best when combined with Si, followed by Sr, Rb, Y, Zr, P, and B. S
In the case of i (similarly, Rb), the K absorption edge is included in the short wavelength region of the exposure wavelength region, so that it is slightly different from the result of Expression (9).
Actually, D = 547.46 nm, Δφ _D = 0.235π
Sr is the most excellent material in combination with Au. Au has _a large maximum phase shift amount Δφ _a / da per unit thickness, and the phase characteristic Δφ _a is 0.25π.
It is difficult to greatly change the characteristics only by improving the value to 0.22π. Characteristics of a single element, to characterization of compounds consisting of these elements is effective, D, [Delta] [phi _D is the average of the constituent elements.

Accordingly, the thickness D of the permeable membrane and the absorber is small (D ≦ 1 μm), Δφ _D is small, and the melting point is high (≧ 15).
00 ° C.) are Si, Zr, SrO, SiO ₂ , S
rS, Y _x Si _y , SiP, Sr ₃ P ₂ , ZrP, Zr
Si, it can be predicted that _{Y 2 O 3, Y x S} y.

B) A combination of a Cu absorber and various single element permeable membranes
The phase characteristics when combined (Table 18) show that the phase
Is the maximum displacement from π at Δφ_DShown as
Elements are arranged in order from the element with the lowest value. In Cu, paired with Ti
Best when combined, then Y, C, Si, Sr,
Sc, then V. Cu is the phase shift per unit thickness.
Maximum displacement of the shaft Δφ_a/ D_aIs small, excluding Mo
It is possible to use all the elements in Table 18
Phase characteristics Δφ _a= 0.13π is easy to improve
You.

Therefore, the thickness D of the permeable membrane and the absorber is small (D ≦ 1 μm), Δφ _D is small, and the melting point is high (≧ 15).
00 ° C.) are Si, SiO ₂ , SrO, SrS,
Y _x Si _y, SiP, and Sr ₃ P ₂ can be predicted.

C) Phase characteristics when the Ni absorber and various single element permeable membranes are combined (Table 19) also shows the maximum displacement as Δφ _D , and the elements are arranged in order from the element having the lowest value. Ni is best when combined with V, then Y, C, Si, Cr, Ti,
The order is C. Ni has _a small maximum displacement Δφ _a / da of the phase shift per unit thickness similarly to Cu, and it is possible to use all elements except for Na (Table 19),
It is easy to improve the phase characteristic Δφ _a = 0.16π.

Therefore, the thickness D of the permeable membrane and the absorber is small (D ≦ 1 μm), Δφ _D is small, and the melting point is high (≧ 15).
00 ° C.) are Si, SiC, Si ₃ N ₄ , SiO
_{2, SrO, SrS, Y x} Si y, SiP, Sr 3 P 2
Can be predicted.

From the above results, it is easy to find a simple element of the permeable film material that can reduce the phase dispersion with respect to the exposure wavelength for various absorbers whose absorption edges are not included in the exposure wavelength range by the formula (9). Yes, it is considered that a single element indicated to reduce the phase dispersion of the absorber, a compound obtained by combining those elements, or a multilayer film is suitable as a permeable membrane material.

The properties of each transmission film material when actually shifted by π phase are as follows: absorber material: Au, Cu, Ni phase shift amount: π transmission film: SiO ₂ , SrO, SrF ₂ , SiC, Si,
MgO, Al ₂ O ₃ , TiO ₂ Light source: synchrotron radiation (exposure wavelength range: 0.654 to 1.
015 nm) is shown in (Table 20).

[0188]

[Table 20]

In the transmission film material which does not include an absorption edge in the exposure wavelength range, a single element or a compound thereof which is suitable for phase correction in Tables 17 to 19 is used for the transmission film. In the case, the displacement of the phase shift amount |
It can be seen that Δφ _D | has been improved. Where Cu,
The phase characteristics of the Ni absorber are greatly improved by the permeable film, and the Au is not significantly improved, which is in good agreement with the results shown in (Tables 17 to 19).

Further, even if the permeable membrane material does not include the absorption edge,
(Tables 17 to 19) show that they are not suitable for phase correction.
Single elements or compounds that combine them |
Δφ _DIs not improved (eg, Au T
iO_TwoEmbedded structure). Also, the film thickness is different from that of other SiO_Two, S
It must be thicker than rO, SiC, Si permeable membrane material
You. Transmission film material MgO (M
g: K absorption edge 0.9512 nm), Al_TwoO_Three(Al:
(K absorption edge 0.7948 nm) embedded structure
Is the phase characteristic | Δφ in any absorber material._D|
It can also be seen that there is no improvement (see Table 21).

[0191]

[Table 21]

As described above, SiO ₂ , SrO, SiC,
It can be said that the Si permeable film material is suitable for the Au, Cu, and Ni absorbers. The phase characteristics are such that the SrO film is made of Au, Cu, Ni
The phase characteristic | Δφ _D | of the absorber is most improved to be 0.22π, 0.04π and 0.07π, respectively, and SiO ₂ , SiC and Si films are excellent in terms of thinning (Table 20).
reference).

In the present embodiment, only the phase characteristics evaluation using the transmission film when the thickness of the absorber and the transmission film are equal (D _a = D _t (≡D)) is performed. When the thickness of the absorber is different from that of the permeable membrane as shown in FIG.
(B) Even when there is a second permeable membrane as shown in FIG. 3 (c) and FIGS. 3 (b) and 4 (b), evaluation is performed using any one of the equations (9) and (10). It is obvious that the same phase compensation effect can be obtained in such a case.

(Sixth Embodiment) From the fifth embodiment,
It has been shown that it is necessary to select a material having a phase compensation effect according to the absorber material as the transmission film material. It is also important not to reduce the contrast. Here, FIGS. 18 to 22 show the transmission characteristics of the following transmission film materials having a phase compensation effect for wavelengths of 0.2 to 1.2 nm (for comparison, the transmission characteristics of a SiO ₂ film (1 μm thick) are shown. Inserted in all figures).

FIG. 18 shows the transmission characteristics of the Si ₃ N ₄ , SiC, Si, diamond film (1 μm thick). M
g, Al, Si simple element and its oxide material (atomic numbers: 12 to 14), specifically, Mg, Al, Si, Mg
FIG. 19 shows the transmission characteristics of the O, Al ₂ O ₃ , and SiO ₂ films (thickness: 1 μm). Elemental elements of Ca, Sc, and Ti and oxide materials thereof (atomic numbers: 20 to 22).
Sc, Ti, CaO, Sc ₂ O ₃ , TiO ₂ film (film thickness 1)
μm) is shown in FIG. Sr single element and its compound material (atomic number: 38), specifically, Sr, S
FIG. 21 shows the transmission characteristics of the rO, SrF ₂ film (thickness: 1 μm). Y, Zr simple element and its compound material (atomic numbers: 39, 40), specifically, Y, Zr, Y ₂ O ₃ , Z
FIG. 22 shows the transmission characteristics of the rO ₂ film (thickness: 1 μm).

The phase characteristics and melting points of the substances shown in FIGS. 18 to 22 are shown in the following (Table 22).

[0197]

[Table 22]

From the viewpoint of the transmission characteristics and the melting point shown in Table 22, in the exposure wavelength range of 0.7 to 1.2 nm, Si, S
i ₃ N ₄ , SiC, SiO ₂ , SrO film, and diamond and Ca in the exposure wavelength range of 0.3 to 0.7 nm.
O, Sc ₂ O ₃ and TiO ₂ films are shown to be suitable permeable membrane materials.

The results of mask contrast when the above permeable film is combined with Au, Cu and Ni absorbers are shown in Tables 23 to 25 below.

[0200]

[Table 23]

[0201]

[Table 24]

[0202]

[Table 25]

SrF ₂ , MgO, Al ₂ O ₃ , TiO ₂
In each case, the mask contrast was reduced to 80% or less as compared with the case where no transmission film was provided, and the film thickness was changed to other SiO 2.
It is not suitable because it needs to be thicker than ₂ , ₂ , SrO, SiC, Si permeable membrane material. Therefore, the wavelength range of 0.6 to 1
The transmission film material which has excellent transmission characteristics in nm and also has suitable phase characteristics for an absorber substance having a large absorption in this wavelength region is SiO ₂ , SrO, SiC, or Si.

(Seventh Embodiment) In the fifth and sixth embodiments, simple elements and compounds that reduce the phase dispersion when Au, Cu, and Ni are used as the absorber material have been described. It is easier to find a simple element having a small phase dispersion for the absorber from the equations (9) and (10). When a single element or a compound combining those elements, which is indicated to correct the phase dispersion with respect to the absorber from the formulas (9) and (10), and when a multilayer film is used as a transmission film material, the X-ray transmitted through the mask is Phase dispersion is kept small.

Therefore, the X of the permeable membrane embedded structure of the absorber is
It has been shown that the line exposure mask can be expected to suppress the degradation of resolution due to diffraction due to the phase shift effect even in X-ray equal-size exposure using synchrotron radiation. In particular, a mask with a SiO ₂ permeable film has a wavelength range of 0.6 to
It is considered to be one of the most suitable phase shift masks for synchrotron radiation light exposure because it is effective as a phase shift mask in 1 nm X-ray exposure and can be easily formed by existing semiconductor process technology.

The SiO_Two, ZrO, SrF_Two, SiC, S
When i is a transmission film, the π phase in a normal mask
As a result of the shift, in Ni, | Δφ |
From 0.07π to 0.125π in Cu, | Δ
φ | increases from 0.125π to 0.04π to 0.09π,
| Δφ | is from 0.25π to 0.22π
It can be seen that it can be improved to 0.245π. In particular, SrO
When embedded in a turn, the absorber on the membrane and Sr
Each phase φ of X-ray transmitted through O_aAnd φ_tShift
Quantity | φ_a−φ_t| For Ni, Cu, Au absorbers
And each | φ _a-φ_t| ≦ π ± 0.07π, π ±
0.04π, π ± 0.22π, which is the most improved.

Similarly, FIG. 23 to FIG.
The phase characteristics when u, Cu, Ni are combined with the above permeable membrane material are shown.

Here, Si ₃ N ₄ , SiC, Si, C
When (diamond) is used as the permeable membrane, since it is the same substance as the membrane material, it is possible to control the phase by directly creating the absorber pattern shape on the membrane and embedding the absorber. This is simple and preferable because the absorption due to the above can be suppressed, and the film thickness can be reduced and the number of steps can be reduced.

(Eighth Embodiment) In the present embodiment, FIG.
A method for producing an X-ray exposure mask, wherein the absorber shown in FIG.
The preferred absorber and permeable membrane material will be specifically described.

In the case where synchrotron radiation having an exposure wavelength range of 0.6 to 1 nm is used, a Cu absorber and a SiO absorber which are shown to be suitable for phase control and a transparent film material are used.
₂ Select a permeable film, at this time, the depth of the groove of the SiO ₂ permeable film pattern is set to a film thickness for obtaining a desired phase shift amount, a SiO ₂ film is formed and etched on the membrane material, Finally, the absorbent material is buried in the groove in FIG.
An X-ray exposure mask shown in (a) was formed. With the combination of the Cu absorber and the SiO ₂ film, the film thickness for shifting the phase by π is about 0.84 μm. SiO ₂ is made of a light element, has good X-ray transparency, can be easily etched, and can have a vertical side surface of the obtained SiO ₂ pattern, so that the film thickness is larger than the pattern line width. It is a material suitable for embedding the absorber material.

Therefore, it is possible to form a pattern of an arbitrary shape, and it is a mask structure suitable not only for phase control but also when the absorber becomes thicker with respect to the pattern line width. At this time, the shift amount of each of the phase phi _a and phi _t of X-rays transmitted through the absorber and SiO ₂ on the membrane |
φ _a −φ _t | is | φ _a −φ _t | ≦ π ± 0.0, respectively.
9 |, which is the characteristic when performing the π phase shift in the normal mask shown in FIG. 8 | φ ₁ −φ ₂ | ≦ π ± 0.125
It is improved more than π.

[0212] Here, as the embedding technology, reflow
It was created using a sputtering method. SiO_TwoOn the pattern
Absorber of Cu, which is a filling material, is sputtered
After film formation, the wafer is heated to form pattern grooves (e.g.
Pours the embedding material into the
Is processed with high precision. High aspect ratio SiO _Two
Complete embedding of the absorber material in the fine grooves of the pattern
Complete coverage of the bottom and sides is achieved by conventional vacuum evaporation.
It is difficult with the deposition method and the sputtering method,
Formation is extremely difficult. In this embodiment, the embedding
Since the reflow sputtering method is used as the
Fine processing is easy, and reflow / sputter is repeated several times.
By returning Cu to SiO_TwoIn the fine groove of the pattern
Absorber material completely embedded, mask pattern with high accuracy
Could be formed.

The reflow heating in the reflow / sputtering method has the effect of annealing the film and also has the effect of absorbing and absorbing.
The stress of the iO ₂ film is reduced, the stress distribution can be controlled, and the alignment accuracy and dimensional accuracy can be improved. In this case, when the absorber material is formed on the permeable film pattern by using the sputtering method, the chemical vapor deposition method is used to improve the film characteristics (step coverage) in the pattern groove. May be used. In particular, in a structure having a high aspect ratio, a chemical vapor deposition method is effective.

[0214] Here, the description has been made by using the SiO ₂ film as the permeable film. However, an SiON film is also a suitable material as the permeable film material because the stress can be easily controlled at the time of film formation. Various measurements (Auger electron spectroscopy and Rutherford backscattering spectroscopy) show that SiON does not cause thermal diffusion of Cu into the SiON film even at a temperature of 500 ° C. for 1 hour. It is a suitable material for the film pattern layer. Therefore, even when the absorber is buried in the concave portion having a high aspect ratio, the heat treatment can be performed at a high temperature in the SiON permeable film, so that thermal diffusion and void-free burying can be realized, and a highly accurate absorber pattern can be formed. Become.

The absorbent material used here has a relatively low melting point (melting point ≦ 15) in order to lower the reflow temperature.
00 ° C or less) Mn, Co, Ni, Cu, Zn, Ga, L
a, Ce, Pr, Nd, Sm, Eu, Gd, Tb, D
It is desirable to use simple elements of y, Ho, Yb, and Au and alloys thereof.

On the other hand, as the permeable membrane material, the reflow temperature
Relatively high melting point (Melting point ≧ 1500 ° C or less)
Bottom) High melting point diamond, MgO, Al_TwoO_Three,
SiO _Two, Si_ThreeN_Four, SiC, CaO, Ti, TiO
_Two, SrO, SrS, Y_TwoO_Three, YSi, Zr, ZrO
_TwoIt is desirable to use such as. Therefore, the wavelength 0.6-1
In X-ray exposure with synchrotron radiation of nm
Is the transmission characteristic of this wavelength range shown in the sixth embodiment.
Considering the results together, the permeable membrane material is SiO_Two, SrO,
SiC, Si_ThreeN_FourIt is desirable to use diamond
New things are led.

In addition, it is apparent that substances made of the elements constituting these substances, such as SiON, are also suitable permeable membrane materials.

The following Table 26 shows the phase characteristics when embedded in the SiO ₂ permeable film pattern as a single element or alloy having a relatively low melting point as an absorber material.

[0219]

[Table 26]

It was shown that the phase characteristics of each of the single elements and the alloys were greatly improved over the characteristics obtained when performing the π phase shift in the usual mask shown in FIG.

As described above, FIGS.
The advantage of the X-ray exposure mask characterized in that the absorber described in (1) is embedded in the transmission film pattern is as follows.

1) An X-ray exposure mask made of an absorber and a permeable film material, which is indicated as a preferred combination in the fifth embodiment, is an X-ray exposure using synchrotron radiation having a wavelength range of 0.6 to 1 nm. Is a preferable phase shift mask.

2) The SiO ₂ permeable film is made of a light element, has good X-ray permeability, can be easily etched, and can make the side surface of the obtained SiO ₂ pattern vertical so that the line width of the pattern can be reduced. On the other hand, it is a material suitable for embedding an absorber material having a large film thickness.

3) In the reflow sputtering method, the absorber material is heated and poured into the grooves (holes) of the pattern.
The absorber material is completely embedded in the fine grooves of the transmission film pattern having a high aspect ratio, and a mask pattern can be formed with high accuracy.

4) By the flow heating, the stress of the absorber and the permeable membrane can be reduced, and the distortion due to the membrane stress is reduced.

5) Since the thicknesses of the absorber and the transmission film are equal and flat, there is no foreign matter such as dust adhering to the fine pattern concave portions in the X-ray exposure mask on which only the absorber pattern is formed. Even if foreign matter such as dust adheres to the surface, it can be removed only by cleaning the surface.

As described above, in the present embodiment, it is possible to precisely control not only a desired phase difference but also a mask contrast. Therefore, the mask for X-ray exposure described in the present embodiment, in which these absorber materials are embedded in the transmission film pattern, has a phase shift effect even in X-ray equal magnification exposure using synchrotron radiation. This suppresses the degradation of resolution due to diffraction, and the alignment accuracy and dimensional accuracy are improved by the reduction of film distortion due to low stress. Therefore, a mask suitable for application to an ultra-fine pattern forming technology of 0.2 μm or less. It is.

Next, in the present embodiment, the absorber material having the excellent phase controllability and the conventional absorber material have a size of 0.2 mm.
1μm various patterns (holes, islands, lines,
(Space, line and space) are compared. As a mask, the mask structure shown in FIGS. 1 and 2 to 4, the synchrotron radiation light is a light source having a radiation light intensity of a wavelength range of 0.6 to 1 nm shown in FIG. 5, and the gap length between the wafer and the mask is 5 to 10 μm. By obtaining the distribution of the X-ray intensity projected on the wafer coated with the negative resist when the same-size proximity exposure is performed,
Evaluate each characteristic. As the absorber, the following 1) Cu (copper: atomic number 29) embedded structure in SiO ₂ film π phase absorber film thickness: da = 843.01 nm π phase shift amount: | φa−φt | ≦ π ± 0.09π 2) Ta (tantalum: atomic number 73) π phase absorber film thickness: da = 679.50 nm π phase shift amount: | φ ₁ −φ ₂ | ≦ π ± 0.54π Compared.

At this time, the dose (or the logarithm of the light intensity) at each position on the wafer when the gap length between the mask and the wafer is changed (commonly called Exposure-
GapTrees), to evaluate exposure latitude. A region between doses of exposure light required to obtain a pattern having a relative difference of ± 10% or less with respect to a pattern size in a gap length between a certain mask and a wafer (here, since the pattern size is 100 nm, 90 nm size) Is defined as the exposure latitude (Exposure Latitude), and the exposure latitude when the gap length is changed to 5 to 10 μm was determined. In addition, the overlapping area of the exposure latitude for all patterns of holes, islands, lines, spaces, and lines and spaces is defined as an exposure window. Therefore, it can be said that the X-ray exposure mask is an excellent X-ray exposure mask that has a process latitude and an exposure latitude as the exposure latitude and the exposure window are larger.

[0230] changing the absorber layer thickness of Cu-SiO _2, Ta, a result of evaluation of the exposure characteristics, Cu-SiO ₂ of X
In a line exposure mask, at a film thickness of about 550 nm,
In the Ta X-ray exposure mask, it was shown that the exposure latitude and the exposure window were maximized at a film thickness of about 400 nm. At this optimum film thickness, Cu—SiO ₂
The mask using Ta as the absorber has a larger exposure latitude and exposure window than the mask using Ta as the absorber, and has a gap length of 10 mm.
The size of the exposure allowance of the line and space pattern in μm is about 1.3 times, and the size of the exposure window in the gap length of 5 μm is 14.4 times larger than that of Ta.

These results indicate that the absorption characteristics of the Cu—SiO ₂ and Ta absorbers are almost the same (the mask contrast of Cu—SiO ₂ and Ta at an absorber film thickness of 400 nm is 3.42, respectively). ~ 3.61,
3.43 to 3.58, see Table 6), which is apparently due to its phase controllability.

In the equal-size X-ray proximity exposure, since the gap length between the mask and the wafer is larger than the pattern size and the influence of light diffraction and a geometrical optical path difference occur, the phase shift amount due to the absorber is not necessarily π. Is not always optimal, but since the rate of displacement of the phase shift amount in the wavelength region does not change even when the film thickness changes, controllability of the phase shift amount is indispensable.

Cu—SiO ₂ satisfies the following 1) Δφ ≦ 0.10π (0.95 ≦ | co
sφ | ≦ 1) The maximum and the minimum phase shift amount of the phase shift amount with respect to the wavelength within the exposure wavelength range are ± the average phase shift amount within the exposure wavelength range.
Within 10% 2) Mask contrast value C at π phase shift film thickness
3) A suitable absorber which satisfies all three conditions of π phase shift film thickness d _a ≦ 1000 nm (aspect ratio 10 or less in L / S 0.1 μm width pattern) Material.

In the method of exposing these materials using an X-ray exposure mask using an absorber, the mask contrast is appropriate and the difference in the phase shift amount of the wave transmitted through the absorber over a wide range of exposure wavelengths. It becomes substantially constant, the phase shift amount of the transmitted wave is controlled, and the effect of the phase shift mask is also provided. Therefore, the resolution of the transfer pattern is remarkably improved, which is suitable for transferring a fine pattern. In addition, here, the result when the phase shift amount is π is described. However, in a halftone mask such as an X-ray exposure mask, the condition that the phase shift amount is π is not always optimal.
The relationship between the absorption characteristic (mask contrast) and the phase characteristic becomes important, and the suitable mask contrast value and phase shift amount vary depending on the pattern to be transferred, the gap length between the mask and the wafer, and the experimental conditions of the resist material. 3
If the absorber material and the combination of the absorber material and the transmission film material satisfying the above conditions described in the seventh to seventh embodiments are used, an X-ray exposure mask having a desired mask contrast value and phase shift amount ( It is clear that it is easy to form a phase shift mask). Also,
There are substances satisfying the three conditions also in the substances shown in (Tables 11, 14, and 26) and the binary compounds of the composition ratios other than those described above, the groups III and IV, and the combinations of the groups I and IV.

Here, Co (cobalt),
Ni (nickel), Cu (copper), Zn (zinc), Ga
(Gallium), lanthanoid rare earth element (atomic number 5
7-71) La (lanthanum), Ce (cerium), P
r (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), Eu (europium), Gd (gadolinium), Tb (terbium), D
y (dysprosium), Ho (holmium), Er (erbium), Tm (thulium), Yb (ytterbium), Lu (lutetium) and alloys thereof, and Cr
(Chromium), Mn (manganese), Fe (iron), Hf (hafnium), Ta (tantalum), W (tungsten),
Any of Re (rhenium), Os (osmium), Ir (iridium), Pt (platinum), Au (gold), Hg (mercury) and a lanthanoid rare earth element (atomic number 57)
It has been clarified that when an alloy with any one of the elements (1) to (7) is used, a desired amount of phase shift can be controlled and a mask contrast can be accurately obtained.

(Ninth Embodiment) In the eighth embodiment,
Although the method of forming the X-ray absorber and the permeable film when a substance having a lower melting point than the permeable membrane material is selected as the absorber material has been described, in the present embodiment, on the contrary, the absorber having a higher melting point is added to the absorber. The method of forming the X-ray absorber and the permeable membrane when a substance having a higher melting point than the permeable membrane material is selected as the body material will be described.

An absorber pattern is formed first, and then a permeable film is deposited on the absorber pattern to form a film, so that the permeable film is embedded in the absorber pattern groove. The deposition and film formation processes at this time are performed by a sputtering method or a chemical vapor deposition method, and a permeable film is buried in the absorber pattern groove by a heating process performed subsequently to this process.

In this embodiment, Sr was used as a transmission film material and Au was used as an absorber material in X-ray exposure using synchrotron radiation having a wavelength of 0.6 to 1 nm. Sr
And Au have melting points of 770 ° C. and 1064 ° C., respectively, and can form a structure in which a permeable film is embedded in the absorber pattern groove shown in FIGS. 2 to 4 by a reflow process. The expression (9 ′) indicates that the Sr permeable film is an element having a large phase compensation effect on Au (Table 17).
), The phase dispersion is actually Δφ _D = 0.2
Δφ _D can be improved from 5π to 0.225π. Similarly,
The absorber material by Sr permeable membrane be replaced by Pt, the phase dispersion can be improved from Δφ _D = 0.27π to Δφ _D = 0.25π.

As described above, the permeable membrane material used here is an element whose melting point is lower than that of the absorber material, and whose absorption edges are all in the region shorter than the shortest wavelength or longer than the longest wavelength of the exposure wavelength region, or It is a simple element, a compound, or a laminated film composed of an element having an absorption edge in the vicinity of the shortest wavelength (within 0.1 nm).

In exposure using synchrotron radiation having a maximum light intensity wavelength of 0.6 to 1 nm, substances meeting the above conditions include Ca, Sr, B having a melting point of 1000 ° C. or less.
a elemental element a and these compounds.

On the other hand, the absorber material is a substance whose melting point is higher than the melting point of the permeable membrane material, and all the absorption edges are in the region of the shortest wavelength or less or the longest wavelength or more of the exposure wavelength range. It is desirable to use a material which is a laminated film and has a large absorption at the exposure wavelength.

In exposure using synchrotron radiation having a maximum light intensity wavelength in the range of 0.6 to 1 nm, substances meeting the above conditions have a melting point of Os, Ir, P having a melting point of 1500 ° C. or more.
t elemental elements and alloys thereof.

(Tenth Embodiment) In this embodiment, when a broadband exposure light source such as synchrotron radiation is used, each element and compound when various simple elements and compounds are used for the absorber are used. Shows an exposure wavelength range excellent in phase controllability. When an exposure light source having a wavelength distribution within the exposure wavelength range suitable for the absorber material is used, the amount of phase shift is constant over the wavelength range of the exposure light, and the phase shift effect improves the pattern accuracy of the exposure object.

As the exposure wavelength range, a wavelength range having an intensity of 1/10 or more of the light intensity at the wavelength of the maximum light intensity incident on the X-ray exposure mask is defined as an exposure wavelength range. In a π phase shift mask 1) Exposure wavelength range that satisfies | Δφ | ≦ 0.10π (0.95 ≦ | cos φ | ≦ 1) where φ: Absorber film thickness in π phase shift average film thickness within exposure wavelength range Maximum displacement from π. Accordingly, 1) means that the maximum and minimum phase shift amounts with respect to wavelengths within the exposure wavelength range are within ± 10% of the average phase shift amount within the exposure wavelength range.

2) Δλ = the longest wavelength of the exposure wavelength range−the shortest wavelength of the exposure wavelength range ≧ 0.4 nm 3) The simplest elements and compounds satisfying the shortest wavelength of the exposure wavelength range of 1.5 nm or less are shown in Table 27 below.
28).

[0246]

[Table 27]

[0247]

[Table 28]

At this time, each element and compound are classified into the following five according to the shortest wavelength in the exposure wavelength range, i) shortest wavelength 0.4 to 0.6 nm ii) shortest wavelength 0.6 to 0.8 nm iii) Iv) Shortest wavelength 1.0 to 1.2 nm v) Shortest wavelength 1.2 to 1.5 nm Further, absorption coefficient α at the center wavelength of the exposure wavelength region, π phase shift average film thickness d, and 1 / exp (−α × d) is shown. The mask contrast value changes depending on the intensity distribution of the synchrotron radiation, etc. Here, 1 / exp (−
α × d) is | Δφ | ≦ 0.10π (0.95 ≦ | cos φ | ≦
This is a measure of the mask contrast value when the exposure wavelength range that satisfies 1) is used.

Each of the elements and compounds listed in Tables 27 and 28 has a large value of 1 / exp (−α × d), and has a synchrotron having a wavelength distribution within the exposure wavelength range shown in this table. It is clear that the use of synchrotron radiation results in an absorber material having excellent phase and absorption characteristics. Therefore, it is important to select a material for the absorber according to the exposure wavelength range of synchrotron radiation used for exposure.

Further, from Lu of atomic numbers 71 to 79 to A
The elemental elements up to u and their compounds are in the following wavelength range: Lu: 1.36 nm ≦ λ ≦ 7.37 nm Ta: 1.27 nm ≦ λ ≦ 7.08 nm Ta ₄ B: 1.27 nm ≦ λ ≦ 7. 08 nm Ta ₄ Ge: 1.35 nm ≦ λ ≦ 8.07 nm W: 1.25 nm ≦ λ ≦ 6.92 nm Re: 1.21 nm ≦ λ ≦ 5.89 nm Os: 1.49 nm ≦ λ ≦ 5.98 nm Ir: 1 0.34 nm ≦ λ ≦ 7.40 nm Pt: 1.28 nm ≦ λ ≦ 5.37 nm Au: 1.03 nm ≦ λ ≦ 5.57 nm In a wide wavelength range, when the exposure wavelength range Δλ is 0.4 nm or more, | Δφ | ≦ 0.10π (0.95 ≦ | cos φ | ≦ 1). Further, in the wavelength range of 1 nm or more, any of the elements and compounds has a large absorption and the π phase shift film thickness is small, so that they are suitable absorber materials in this exposure wavelength range.

(Eleventh Embodiment) Next, an embodiment of an exposure apparatus for manufacturing a micro device (semiconductor device, thin-film magnetic head, micromachine, etc.) using the above-described mask will be described.

FIG. 26 is a diagram showing the configuration of the X-ray exposure apparatus of the present embodiment. The light emitted from the synchrotron radiation light source 14 was condensed by the condensing mirror 22, the X-ray intensity was increased, the light was shaped into parallel light by the oscillating mirror 23, and the exposure area was scanned to increase the exposure area. Here, in the exposure method in which the synchrotron radiation light is reflected by the X-ray mirror, a large difference occurs in the wavelength distribution depending on the exposure position. However, in the X-ray exposure mask according to the present embodiment, the phase shift amount shows wavelength dependence. Therefore, uneven exposure and deterioration of resolution can be suppressed.

The X-ray extraction window has a diamond window 2
4, a beryllium window 25 and a silicon nitride window 26 were provided in three stages, respectively, to isolate ultrahigh vacuum A / high vacuum B, high vacuum B / atmospheric pressure helium C, and helium C / air D. The X-ray exposure mask 27 has the structure described in any of the embodiments described above, and the above conditions are set so that the maximum intensity wavelength of the exposure light transmitted through the membrane is 0.6 to 1 nm. The pattern formed on the X-ray exposure mask 27 is changed by a step-and-repeat method, a scanning method, or the like.
Exposure transfer is performed on a wafer 29 held on a wafer stage 28.

(Twelfth Embodiment) Next, a method of manufacturing an X-ray exposure mask according to the present invention will be described.

FIGS. 27 and 28 are sectional views showing the steps of manufacturing an X-ray exposure mask according to the twelfth embodiment of the present invention.

First, as shown in FIG. 27A, a 525 μm-thick 4-inch Si (100) wafer 1
01, a silane gas 15 diluted with 10% hydrogen was used at a substrate temperature of 1250 ° C. and a pressure of 30 Torr by using a low pressure CVD method.
Acetylene gas 65sccm, 0sccm, 10% hydrogen dilution
100% hydrogen chloride gas 150 sccm was introduced into the reaction tube together with 10 SLM of hydrogen as a carrier gas, and the X-ray transparent thin film 1 was introduced.
A 2 μm-thick SiC film having a thickness of 02 was formed. Subsequently, the surface of the substrate was coated with Ar using an RF sputtering apparatus.
Under a pressure of 1 mTorr, a 98 nm-thick alumina film serving as an antireflection film and an etching stopper 103 was formed.
Then, on the anti-reflection film / etching stopper 103,
0.8 μm in film thickness by CVD using TEOS as a main material
forming an SiO ₂ film to be a patterning layer 104 of m
The stress of the SiO ₂ film was adjusted to almost 0 MPa by performing an annealing treatment after the film formation.

Next, as shown in FIG.
Using an E apparatus, using an aluminum etching mask (not shown), a pressure of 10 mTorr and an RF power of 200 W, a CF ₄ gas of 25 sccm and an O ₂ gas of 40 sccm are supplied, and a 70 mm radius area at the center of the back surface is used. The opening region 105 serving as a mask for back etching by removing the SiC film.
Was formed.

Next, as shown in FIG. 27C, a glass ring having an outer diameter of 125 mm, an inner diameter of 72 mm, and a thickness of 6.2 mm was formed as a frame 106 using an ultraviolet-curable epoxy resin adhesive (not shown). The substrates were joined to form a substrate. Further, using a back etching apparatus, a 1: 1 mixture of hydrofluoric acid and nitric acid is dropped on the portion where the SiC has been removed,
The Si wafer 101 was removed by etching.

Next, as shown in FIG.
Commercially available positive resist for electron beam Z on O ₂ film 104
EP-520 (viscosity 12 cps) with rotation speed 2000 rpm
m, 50 seconds, and baked at 175 ° C. for 2 minutes using a hot plate.
m of the photosensitive film 107 was formed. And the acceleration voltage 75k
A pattern was drawn on the photosensitive film 107 using a V electron beam drawing apparatus. In order to obtain a desired writing accuracy, writing was performed by multiple writing in which a pattern was formed by overwriting four times, and the proximity effect correction was performed by correcting the irradiation amount while setting the reference irradiation amount to 96 μC / cm ² .

After the pattern was drawn, development was carried out using a commercially available developer ZEP-RD at a liquid temperature of 18 ° C. for 1 minute, followed by rinsing with MIBK for 1 minute to remove the developer. Subsequently, based on the formed resist pattern, the SiO ₂ film 104 was processed by reactive ion etching using CHF ₃ and CO gas. Thereafter, the remaining resist 107 was removed by ashing in oxygen plasma and then washed in a mixed solution of sulfuric acid and hydrogen peroxide.

Next, as shown in FIG.
Under a condition of an Ar pressure of 3 mTorr using a sputtering apparatus, a 0.6 μm-thick copper (C
forming a u) film, Then, as shown in FIG. 28 (b), in the sputtering in the same vacuum, 550 ° C., subjected to a thermal treatment for one minute, the aggregating buried in the recesses of the pattern of the SiO ₂ film 104 went.

Finally, unnecessary Cu was removed by the following method called resist etch back. First, the same apparatus as used in the previous resist coating was used, as shown in FIG.
As shown in (c), a commercially available electron beam resist ZE
P-520 (viscosity 12 cps) with rotation speed 2000 rpm
m, 50 seconds, and baked at 175 ° C. for 2 minutes using a hot plate.
m of the resist film 109 was formed. At this time, due to the characteristics of spin coating, the surface has a substantially flat coating shape.

Next, as shown in FIG.
The mask surface was etched by reactive ion etching using r gas until the SiO ₂ surface was exposed, under the condition that the etching rates of the resist film 109 and the Cu film 108 were almost equal.

A desired mask for X-ray exposure can be prepared by the above method. However, it has been found that the mask prepared according to the present embodiment has the following advantages.
First, it is possible to control the internal stress of the absorber to a desired value, which makes it possible to easily obtain a highly accurate X-ray exposure mask. This is for the following reason.

In the conventional X-ray absorber directly processed by reactive ion etching, the internal stress generated during the film formation of the absorber remains as it is. Therefore, in order to form a highly accurate mask for X-ray exposure, It was necessary to control the film-forming conditions of the absorber with high accuracy, and it was necessary to suppress the occurrence of in-plane stress distribution to an extremely small value of 5 MPa or less. On the other hand, in the present embodiment, the so-called reflow is caused by performing the coagulation embedding by performing the heat treatment after the film formation of the absorber. Stress depends only on the reflow process. That is, as long as the temperature control in the reflow process including the in-plane uniformity is sufficiently controlled, it is possible to form an absorber having a desired internal stress. Normally, stress adjustment by temperature control in the reflow step is much easier than stress control in the sputtering step, and a stress distribution of about 1 MPa can be obtained. A line exposure mask can be easily obtained.

Second, in this embodiment, an apparatus having the same coating characteristics as those of the first resist coating step for forming a mask pattern and the second resist coating step for performing resist etch-back, More preferably, since the same apparatus is used, it is possible to improve dimensional accuracy when performing transfer exposure using the prepared mask, as described below.

As is generally known, when electron beam drawing / developing is performed in the case where there is a distribution in the resist film thickness, even if the same pattern is drawn under the same conditions, as shown in FIG. Corresponding to the resist film thickness, the dimension is smaller in the thick resist portion than in the thin resist portion. Specifically, there is a case where a dimensional change of about 1% occurs with a resist film thickness change of 1%. However, when the resist etch-back step is performed using a resist coating apparatus having the same coating characteristics as in the present embodiment, the dimension is reduced due to a large resist film thickness during electron beam writing. As shown in FIG. 29 (b), since the resist film thickness becomes large even in the resist etch-back step, after the resist etch-back step is completed,
As shown in (c), an absorber having a larger thickness is formed in a portion where the absorber becomes smaller due to the distribution of the resist film thickness than in a portion where the absorber becomes larger.

When such a mask is used for actual exposure, the portion where the absorber has become smaller has a higher contrast because of the thicker film, and the portion where the absorber has become larger has a larger thickness. The contrast is reduced due to the thin film thickness. Therefore, it has been found that the dimensions of the pattern obtained by the transfer are offset by each other, thereby improving the pattern dimension uniformity and improving the dimensional accuracy.
That is, according to the present embodiment, it is possible to relieve the dimensional accuracy deterioration of the transfer pattern caused by the distribution of the absorber size generated due to the resist coating film thickness distribution.

In the present embodiment, a film of another material that can be spin-coated, such as an SOG film or an ITO film that can be spin-coated, may be used instead of the resist film 109.

Using the mask manufactured by the above-described process, the SOR light source was used to apply a light beam having a center wavelength of 0.8 nm using a beam line provided with a mirror and a vacuum partition Be film to the Si wafer. When the pattern was transferred to the resulting resist, a pattern having a line width of 70 nm could be formed.

(Thirteenth Embodiment) In the twelfth embodiment, excess Cu remaining on a flat portion is removed by a resist etch-back method. However, if an apparatus having the following mechanism is used, polishing is performed. It is also possible to remove by a method. With a conventional polishing apparatus, it is difficult to perform polishing of an object composed of a self-supporting thin film such as an X-ray exposure mask. However, in the present embodiment, the surface to be polished of the mask is filled with a fluid, This is made possible by controlling the pressure of

FIG. 30 is a sectional view for explaining a polishing apparatus according to this embodiment. A polishing pad 212 made of a resin-impregnated non-woven fabric is mounted on a rotatable polishing platen 211 in the same manner as a normal polishing apparatus, and an abrasive 213 is supplied from an abrasive tank 214 via an amount control mechanism 215 to the abrasive. There is provided a mechanism that discharges near the polishing pad 212 through the supply pipe 216.

The mask 217 after the completion of the reflow step is
It is fixed to a base 219 by a clamp 220 via a rubber O-ring 218. The pedestal 219 has an inflow pipe 222 and an outflow pipe 223 of pure water serving as a pressure adjusting fluid 221.
Are connected, and the entire pedestal is connected to a rotatable mechanism. A pressure gauge 224 is connected to the outflow pipe 223,
Flow control mechanisms 225a and 225b, each including a flow control valve, are connected to the inflow pipe 222 and the outflow pipe 223, respectively, and the flow rate is controlled in accordance with the output of the pressure gauge 224 so that the pressure of the fluid 221 in the pedestal portion is constant. There is a mechanism that can be adjusted. In addition, the fluid is circulated through the constant temperature device 226, and the temperature of the surface to be polished during polishing can be kept constant, so that a temperature-sensitive process can be stabilized. I have.

In order to further improve the accuracy, the pedestal 219
Is mounted with a sensor 227 for monitoring the distance to the X-ray transparent thin film of the mask. The output of the sensor 227 is taken into the control computer 228, and if necessary, not only the pressure gauge 224 but also the distance sensor 227 is provided. Can be used in combination to control the pressure of the fluid 221. In general, the displacement of the X-ray exposure mask surface is very sensitive to pressure, and in the polishing process, the uniformity of the shape of the polishing surface is important in the process control together with the pressure on the polishing surface. The use of a sensor for monitoring the distance to the X-ray exposure mask surface plays a large role in stabilizing the polishing process. For pressure management, in addition to the flow control valve, a volume deformable mechanism 229 constituted by a cylinder is provided to control the volume occupied by the fluid between the two flow control valves, thereby achieving more precise control. A mechanism capable of controlling pressure is provided.

More specifically, in the twelfth embodiment,
The substrate after the reflow process (FIG. 28B) is
Fluid pressure is 300g / c
While controlling the height of the X-ray exposure mask surface to be constant under the condition of m ² , the polishing platen 211 and the pedestal 219 are controlled.
The abrasive 213 was supplied to the polishing pad 212 at a rate of 10 ml / min while rotating each of them in a direction opposite to each other at a rotation speed of 100 rpm to remove excess Cu. For the abrasive, 0.12 mol / l of glycine (C
A mixed solution of ₂ H ₅ O ₂ N) aqueous hydrogen peroxide aqueous solution and _{0.44mol / l (H 2 O 2} ), were dispersed with silica particles having an average particle size 30nm with 5.3% by weight abrasive particles ,
0.001 mol / l of benzotriazole (C ₆ H ₅
N ₃ ) was used.

The polishing rate of Cu under the above conditions is about 9
It was 0 nm / min, and it was found that processing could be performed at a sufficient speed. The end point of the polishing step was detected by using a method of monitoring a change in the voltage of the drive motor of the polishing platen together with the processing time. In other words, the voltage of the drive motor of the normal polishing platen rises immediately after the start of polishing and becomes almost constant, and rises again from the time when Cu remaining on the wide flat portion is almost removed. Is detected and the polishing process is terminated.
Processing can be performed with good reproducibility. The substrate after polishing is removed from the polishing apparatus, washed with pure water to remove the abrasive, and further immersed in 0.001% dissolved ozone water for 3 minutes. By immersing in a 90% dilute hydrofluoric acid aqueous solution for 90 seconds, organic substances and the like remaining on the surface are removed, and finally, the substrate is washed with pure water to complete a series of processes.

In this embodiment, it is important that the polishing apparatus has a mechanism capable of processing the X-ray exposure mask, and the polishing pressure, the rotation speed of the polishing platen / pedestal, and the end point detection Method, it is also possible to use various other methods for polishing conditions such as abrasives,
For example, the end point can be detected by monitoring the pH of the polishing agent on the polishing pad, the temperature of the polishing pad, and the like. As for the abrasive, it is also possible to use alumina particles, titanium oxide particles, zirconium oxide particles, cerium oxide particles, silicon carbide particles, diamond particles, or a mixture of these particles including silica particles instead of silica particles.
Further, other aminoacetic acid, aminosulfuric acid, or a mixture thereof can be used in place of the glycine aqueous solution, and nitric acid, hypochlorous acid, ozone water, ammonium nitrate, ammonium chloride can be used in place of the hydrogen peroxide solution. , Chromic acid or the like can also be used. In addition, the addition of benzotriazole is not always necessary, and when it is added,
It is also possible to use benzotriazole derivatives, thiourea, thiourea derivatives, benzimidazole, triazole, ethylenediamine, cysteine, and mixtures containing these, as long as the material forms a chelate compound or complex compound with the material to be polished. is there.

Using the mask manufactured by the above-described process, the SOR light source was used to apply a light beam having a center wavelength of 0.8 nm using a beam line provided with a mirror and a vacuum partition Be film, and then applied onto a Si wafer. When the pattern was transferred to the resulting resist, a pattern having a line width of 70 nm could be formed.

[0279] As design rules become finer,
When the desired absorber aspect ratio increases, one reflow
Process can completely fill the recesses of the pattern
Difficult, but in that case sputtering and reflow
Can be embedded by dividing the
No. Specifically, a Cu film having a thickness of 0.6 μm is formed at a time.
Instead of using, for example, RF sputtering equipment
And the thickness of the absorber 8 under the condition of an Ar pressure of 3 mTorr.
Form a 2μm Cu film, and in the same vacuum as sputtering
And heat-treated at 550 ° C. for 1 minute to form recesses in the pattern.
A series of steps of performing cohesive embedding is repeated three times
Thus, the embedding may be performed. Also, in this case,
If necessary, perform each heat treatment step and the next sputtering step.
In the meantime, resist etch back or polishing
SiO with a relatively large area _TwoOn membrane 4 pattern
Unnecessary Cu can be removed in advance.

In the above embodiments, Cu was used as the absorber, but the present invention is not limited to Cu, but is applicable to W, Ta, R
The present invention can be applied to a case where another absorber material such as u, Re, Au, Os, Zn, Pb, Pt or a compound containing these materials is used. These materials have a high melting point (including those for which the reflow step is difficult, but the reflow step itself is not essential to the present invention and can be omitted. In that case, the resist etch-back step or the By performing the polishing step, a desired mask can be formed, and the method of forming the absorber is not limited to sputtering, but may be mere vapor deposition, electrolytic plating, electroless plating, thermal CVD, or plasma CV.
Various methods such as D can be used. When using electrolytic plating, an anti-reflection film and an etching stopper 1
It is convenient to replace 03 with a conductive substance, for example, a metal thin film of Cr, Ni or the like, an ITO film, or the like.

According to the present embodiment, fine processing of the absorber of the mask for X-ray exposure can be performed without including the step of directly processing the absorber by RIE, so that a material which is difficult to be subjected to RIE is obtained. Can easily be used as an absorber material, and it is possible to prevent pattern accuracy deterioration due to residues generated during RIE.

(Fourteenth Embodiment) Here, a method for forming a 1: 1 X-ray exposure mask will be specifically described. FIGS. 31 and 32 are cross-sectional views showing the steps of manufacturing the X-ray exposure mask used in the fourteenth embodiment of the present invention.

First, the steps of manufacturing the template 300 will be described. As shown in FIG. 31A, a 525 μm-thick 4-inch Si (100) wafer 301 is cleaned.
Substrate pressure 1025 ° C., pressure 3
Under the condition of 0 Torr, silane gas diluted with 10% hydrogen 150 sc
acetylene gas diluted with 10% hydrogen 65 sccm, 100
% Hydrogen chloride gas 150 sccm and hydrogen 1 as carrier gas
The X-ray transparent thin film 30 is introduced into the reaction tube together with the 0 SLM.
A 2 μm-thick SiC film having a thickness of 2 was formed.

Next, as shown in FIG. 31B, a 98 nm-thick alumina film serving as an anti-reflection film and an etching stopper 303 was formed on the surface of this substrate by using an RF sputtering apparatus under the condition of an Ar pressure of 1 mTorr. A film was formed. Further thereon, an 800 nm-thick patterning layer 304 is formed by CVD using TEOS as a main material.
The stress of the SiO ₂ film was adjusted to almost 0 MPa by forming an O ₂ film and performing an annealing treatment after the film formation.

Next, using a RIE apparatus, aluminum was used as an etching mask under the conditions of a pressure of 10 mTorr and an RF power of 200 W, a CF ₄ gas of 25 sccm and an O ₂ gas of 4
0 sccm, as shown in FIG. 31 (c), a 70 mm radius area at the center of the back of the template, and SiC on the back of the transfer substrate.
The film 302 was removed, and an opening region 305 serving as a mask for etching the Si wafer 301 was formed.

Then, as shown in FIG. 31D, a commercially available positive resist for electron beam ZEP52 is formed on this substrate.
0 (viscosity: 12 cps) is spin-coated under the conditions of a rotation speed of 2,000 rpm and 50 seconds, and 175 using a hot plate.
A baking treatment was performed at 2 ° C. for 2 minutes to form a photosensitive film 306 having a thickness of 300 nm. Then, pattern writing was performed using an electron beam writing apparatus with an acceleration voltage of 75 kV. In order to obtain a desired writing accuracy, writing is performed by multiple writing in which a pattern is formed by overwriting four times, and the reference irradiation amount is set to 96 μm.
As C / cm ² , proximity effect correction was performed by irradiation amount correction. After drawing, a commercially available developer ZEP-R is used as a developing process.
Using D, development was carried out at a liquid temperature of 18 ° C. for 1 minute, followed by rinsing with MIBK for 1 minute to remove the developer.

Next, as shown in FIG. 31E, using the pattern (resist pattern) of the photosensitive film 306 as a mask,
The SiO ₂ film 304 was processed by reactive ion etching using CHF ₃ and CO gas. The remaining resist was removed by ashing in oxygen plasma, and then washed with a mixed solution of sulfuric acid and hydrogen peroxide. Thus, the template 300 was formed.

Next, the manufacturing process of the (transfer) substrate 400 to which the template 300 is pressed will be described. First, as shown in FIG. 32 (a), in the same manner as in the template manufacturing process, one side surface of a cleaned 525 μm-thick 4-inch Si (100) wafer 401 is heated at a substrate temperature of 10 by using reduced pressure CVD.
Under conditions of 25 ° C. and a pressure of 30 Torr, silane gas diluted with 10% hydrogen 150 sccm, acetylene gas diluted with 10% hydrogen 6
5 sccm and 50 sccm of 100% hydrogen chloride gas were introduced into the reaction tube together with 10 SLM of hydrogen as a carrier gas to form a 2 μm-thick SiC film to be the X-ray transparent thin film 402.
Subsequently, the Ar pressure was set to 3 m using an RF sputtering apparatus.
Under the condition of Torr, the film thickness of the X-ray absorber 403 becomes 0.6
A μm layer of copper (Cu) was formed, and the surface was flattened by polishing.

Next, as shown in FIG. 32 (b), both the template 300 and the transfer substrate 400 are brought into close contact with each other, a pressure of about 5 to 30 MPa is applied by a press device, and simultaneously, infrared irradiation is performed at 550 ° C. for 1 minute. Was heat-treated.

By this process, as shown in FIG. 32C, the Cu metal layer 403 as the X-ray absorber is pushed into the pattern concave portions of the SiO ₂ film 304, and heat is applied to the Cu metal portion. Then, Cu metal flowed into the pattern concave portions to perform coagulation embedding.

Next, as shown in FIG. 32D, the Si portion on the opening region 305 of the template 300 from which SiC has been removed and the Si wafer 401 portion of the transfer substrate 400 are mixed with 1: 1 hydrofluoric acid and nitric acid. It was removed by etching with a liquid. Finally,
125m outside diameter using UV curable epoxy resin adhesive
A glass ring having a diameter of 72 m, an inner diameter of 72 mm, and a thickness of 6.2 mm was joined as a frame 500.

Although a desired mask for X-ray exposure can be prepared by the above method, it has been found that the mask formed by the present method has the following advantages. First, the conventional nanoimprint lithography method assumed that the template was peeled off. Therefore, high-temperature heating during pressing in this method requires the conventional nanoimprint to increase the adhesion between the two plates and peel off. Becomes difficult. On the other hand, in the present embodiment, the patterning layer 3 of the template 300 is
04 is left as it is and is used as a constituent material of the mask for X-ray exposure, and since the template 300 is not peeled off, high-temperature heating at the time of pressing is effective.

Since the metal is softened at a higher temperature than at room temperature, the force required to press the metal with a pressing device at this time and to push the metal into the pattern concave portion can be reduced. In the conventional method, there is a risk that the mold plate and the transfer substrate may be damaged or deformed by pressing at a high pressure, and therefore, the method is limited to soft metal materials at room temperature. By setting to, it is possible to adapt to various metal materials. further,
The heat treatment also has the advantage that the metal can easily flow into the pattern recesses having a high aspect ratio, and the cohesion and embedding can be easily performed.

[0294] Regarding the internal stress of the absorber, coagulation embedding is performed by performing a heat treatment after film formation.
Since the so-called reflow is caused, the internal stress at the time of film formation is once released, and therefore, it depends only on this reflow step. That is, as long as the temperature control in the reflow process including the in-plane uniformity is sufficiently controlled, it is possible to form an absorber having a desired internal stress. Therefore, the stress control is much easier and the stress control is 1 MPa compared with the high-precision conditions required for the absorber film formation in the absorber pattern formation directly processed by the reactive ion etching of the conventional method.
There is an advantage that it is possible to obtain a degree of stress distribution.

Using the mask manufactured by the above process, a mirror and a vacuum partition (Be film) are used as a synchrotron light source.
Was transferred to the resist applied on the Si wafer using the exposure light having the center wavelength of 0.8 nm using a beam line provided with a laser beam, and a pattern with a line width of 70 nm could be formed with high accuracy. .

In the above embodiment, the template 300 and the transfer substrate 400 are brought into close contact with each other, and after forming an X-ray absorber pattern, the glass plate 500
However, the frame 500 may be bonded to the template 300 before the template 300 and the transfer substrate 400 are brought into close contact with each other. FIG. 33 shows a manufacturing process in this case.

First, SiC to be the X-ray transparent thin film 302 is formed on a Si wafer 301, and an alumina film to be an anti-reflection film and an etching stopper 303 and an SiO ₂ film to be a patterning layer 304 are formed. SiC on the back of the plate
Until the film 302 is partially removed and the opening region 305 is formed, the process is the same as the process shown in FIGS. 31A to 31C.

Next, as shown in FIG. 33A, an ultraviolet-curable epoxy resin is
A glass ring frame 500 having an outer diameter of 125 mm, an inner diameter of 72 mm, and a thickness of 6.2 mm was bonded. Then, FIG.
As shown in (b), the opening region 30 from which SiC has been removed.
5 is removed using a one-to-one mixed solution of hydrofluoric acid and nitric acid, thereby removing the X-ray transparent thin film (membrane).
It was created.

Next, as shown in FIG. 33 (c), a polyimide resin forming solution was spin-coated on the back surface of the membrane to form a thin film 309, which was then heated and dehydrated at 300 ° C. to be cured. Next, as shown in FIG.
A pattern of a resist 306 was formed on the iO ₂ film 304, the SiO ₂ film 304 was selectively etched using the pattern as a mask, and the remaining resist 306 was peeled off.

Thereafter, as in FIGS. 32 (a) to 32 (e), both the template 300 and the transfer substrate 400 are brought into close contact with each other, a pressure of about 5 to 30 MPa is applied by a pressing device, and simultaneously infrared irradiation is performed. At 400 ° C. for 2 minutes. Finally, the polyimide resin 309 is removed by etching with hydrazine, and the Si wafer 401 of the transfer substrate 400 is removed by etching with a 1: 1 mixed solution of hydrofluoric acid and nitric acid.
The desired X-ray exposure mask was obtained.

In the above embodiment, Cu is used as the X-ray absorber 403, but the present invention is not limited to Cu,
o, Ni, Zn, Ga, Ge, Ta, Re, Os, A
The present invention can be applied to a case where another metal material such as u, Pt, Pb, or a compound containing these materials (particularly, brass CuZn) is used. Some of these substances have a high melting point and are difficult to reflow by heating, but the reflow step and the heating step are not essential and can be omitted. Also, in the case of a soft metal such as brass, even if the heating step is performed at a relatively low temperature, the pressing force by the press is small, and the patterning layer can be embedded in the concave portion, and a desired pattern or mask can be formed. Is possible.

In this embodiment, SiO ₂ is used as the patterning layer 304. However, the present invention is not limited to SiO ₂ , but includes Si ₃ N ₄ , SiC, diamond, Si, and TiO 2.
₂ , Al ₂ O ₃ , ZrO ₂ , SiON, SiOF, Si
The present invention can be applied to a case where another material such as OB, BN, TiN, or a compound containing these is used. The method of forming the patterning layer is not limited to the CVD method, and various methods such as simple vapor deposition and sputtering can be used.

[0303] Although a polyimide resin, which is a thermosetting resin, was used here for forming and curing the thin film on the back surface of the membrane, other thermosetting resin materials, polyvinyl acetate, and the like were used.
A solvent-soluble resin such as polyvinyl alcohol, polyvinyl formal, polyvinyl acetoacetal, and polyvinyl butyral may be injected, cured, and dissolved with water or alcohol. In addition, instead of a method of injecting and curing a polyimide resin, as in the case of a polishing apparatus for an object composed of a free-standing thin film such as an X-ray exposure mask, the back surface of the membrane is filled with a fluid, and the pressure of the fluid is increased. Can be used.

The method of forming a metal film is not limited to sputtering, but may be mere vapor deposition, electrolytic plating, electroless plating, or the like.
Various methods such as thermal CVD and plasma CVD can be used. When electrolytic plating is used, it is convenient to replace the anti-reflection film / etching stopper 303 with a conductive material, for example, a metal thin film of Cr, Ni or the like, an ITO film, or the like. Although the heating step is performed by infrared heating here, other heating methods such as a hot plate can be used.

In the embodiment, the patterning layer 304
Since SiO ₂ used as a material having a high X-ray transmittance, the patterning layer was left as it was and could be used as an X-ray exposure mask.
If this patterning layer is unnecessary, a step of removing the patterning layer by etching after forming the absorber pattern may be added. Also, since the X-ray transparent thin film 402 of the transfer substrate 400 is not necessary in the X-ray exposure mask, a step of removing the Si wafer 401 of the transfer substrate 400 after the etching may be added.

In this embodiment, the method of forming the absorber metal pattern on the membrane film has been described. However, in this method, it is possible to adapt to various metal materials by setting the heating temperature to an appropriate temperature, and to adjust the aspect ratio. Since it is easy to form a metal pattern having a high density, the method can be applied not only to the production of an X-ray exposure mask, but also to various lithography and exposure masks for a zone plate. In particular, this is a suitable method for producing various exposure masks that require formation of a fine pattern on a membrane. Further, in various exposure masks, even when a zone plate is used as an alignment mark between the exposure mask and the substrate to be processed on the transfer exposure apparatus, the zone plate region for alignment is preliminarily formed on the transmission film. In this case, it is possible to collectively form the exposure pattern area and to reduce the number of steps and cost for manufacturing a mask.

(Fifteenth Embodiment) In the fourteenth embodiment, a method of forming an X-ray exposure mask using Cu as an X-ray absorber and SiO ₂ as a transmission film on a membrane film has been described. In the embodiment before that, the synchrotron radiation light has an exposure light wavelength range (light intensity of 1/10 or more of the light intensity at the wavelength of the maximum light intensity incident on the X-ray exposure mask). in X-ray exposure using an exposure light source having a the wavelength region and exposure wavelength region) to between 0.65nm of 1.02 nm, the Cu-SiO ₂ X
It has already been described that in a line exposure mask, a change in the amount of phase shift with respect to the wavelength of the exposure light wavelength region of the Cu absorber is reduced by the SiO ₂ transmission film, and the resolution of the transfer pattern is improved by the phase shift effect. .

In the present embodiment, even when the transmission film is made of SiON, the change in the phase shift amount with respect to the wavelength in the exposure wavelength region of the Cu absorber is small, and the resolution of the transfer pattern is improved by the phase shift effect. In addition, it has been shown that the diffusion of Cu into the permeable film is suppressed, and pattern transfer with higher resolution can be performed. Also, X
When a CuZn alloy was used as the line absorber material, the phase characteristics were further improved, and it was shown that application to the manufacturing method described in the fourteenth embodiment was easy, so these inventions are also described below. The description will be made similarly.

In order to produce a high image contrast with respect to the transmission characteristics of the exposure light of the X-ray absorber, it is desired that the transmission film material on the membrane film has a high transmission characteristic for the exposure light. FIG. 34 shows that X-rays having a wavelength of 0.5 to 1.0 μm at a thickness of 1 μm for both the SiON film and SiO ₂ film
4 shows transmission characteristics for a line. The transmission characteristic of the SiON film is S
It has almost the same characteristics as the iO ₂ film,
It has a high transmittance of about 60 to 80% with respect to X-rays of m and is a material suitable as a transmission film material in X-ray exposure using X-rays having a wavelength of 0.5 to 1.0 μm.

Next, FIGS. 35 (a) and 35 (b) show the wavelength dependence of the phase shift amount and the exposure light intensity in the two X-ray exposure masks. FIG. 35A shows an X-ray exposure mask in which only a Cu absorber pattern is formed on a SiC membrane film (thickness: 2 μm), after passing through the SiC membrane, and in the SiC membrane-Cu absorber (each film). (Thicknesses of 2 μm and 0.61 μm) are the characteristics of the exposure light intensity and the phase shift amount after transmission. FIG. 35 (b)
Is an X-ray exposure mask in which a Cu absorber pattern and a SiON transmission film pattern are formed on a SiC membrane film (2 μm thick).
Exposure light intensity and phase shift after transmission through a transmission film (2 μm and 0.90 μm, respectively) and after transmission through a SiC membrane-Cu absorber (2 μm and 0.90 μm, respectively) Is a property of quantity.

The X-ray exposure beam used here is synchrotron radiation and has a ring accumulated electron energy of 600.
MeV, deflection magnetic field 3T, maximum accumulation current 500 mA, maximum exposure area 30 mm square, maximum exposure intensity 50 mW / cm ² ,
The beam parallelism is 2 mrad or less. A beryllium (Be) window having an average film thickness of 25 μm is used as a window for extracting emitted light.
A silicon nitride (Si ₃ N ₄ ) window having an average film thickness of 1.5 μm, a diamond window having an average film thickness of 1.0 μm, and an oblique incidence type platinum (Pt) mirror used as a condensing and oscillating mirror. An intensity spectrum, which is an exposure wavelength range immediately before the light enters the X-ray exposure mask (a wavelength range having a light intensity of 1/10 or more of the light intensity at the wavelength of the maximum light intensity incident on the X-ray exposure mask) Is the exposure wavelength range) is 0.65 to
1.02 nm emitted light.

Here, the maximum value and the minimum value in the exposure wavelength range of the phase shift difference between the respective exposure lights after transmission through the absorber portion and the portion other than the absorber were added, and the value was divided by two. The absorber thickness was set so that the value was π (so-called π
A phase shift mask). At this time, the thickness of the Cu absorber is 612.4 nm, and the difference between the maximum and minimum phase shift amounts corresponds to 0.875π and 1.125π, respectively, and the phase shift amount is within ± 12.5%. Controlled. On the other hand, the film thickness of the Cu—SiON absorber is 903.
At 5 nm, the difference between the maximum and minimum phase shift amounts then corresponds to 0.910π and 1.09π, respectively. At this time, the phase shift amount is controlled to within ± 9.0%. The amount is constant over the entire exposure wavelength range (see FIG. 36).

When the high-intensity region of the exposure light transmitted through the absorber portion is defined as a wavelength region having an intensity equal to or more than の of the maximum light intensity, the region other than the absorber portion and the portion other than the absorber may be used. The maximum value and the minimum value of the phase shift amount difference of the exposure light transmitted through in this wavelength range are 0.90π and 1.01π in the case of the Cu absorber, 0.96π in the case of the Cu-SiON absorber, 101π, which indicates that the X-ray exposure mask using the Cu-SiON absorber can control the amount of phase shift over the entire exposure wavelength range. In the case of an exposure mask in which the amount of phase shift greatly changes in the wavelength range, the resolution of a transfer pattern using the phase shift effect cannot be sufficiently improved, and therefore, in the X-ray exposure using synchrotron radiation of a wide band, Si
A phase shift control method using an ON transmission film is effective in improving the degree of by-image of a transfer pattern.

Next, the manufacturing process of the X-ray exposure mask comprising the Cu absorber and the SiON permeable film will be described.
Since the manufacturing process diagrams are substantially the same as those in FIG. 27 and FIG. 28, they will be referred to.
04 SiO ₂ replaces SiON.

First, as shown in FIG. 27A, a 525 μm-thick 4-inch Si (100) wafer 1
The silane gas 15 diluted with 10% hydrogen was deposited on the substrate 01 at a substrate temperature of 1025 ° C. and a pressure of 30 Torr using a low pressure CVD method.
0 sccm, acetylene gas diluted with 10% hydrogen 65 sccm, 1
150 sccm of 00% hydrogen chloride gas was introduced into the reaction tube together with 10 SLM of hydrogen as a carrier gas to form a 2 μm-thick SiC film to be the X-ray transparent thin film 102. continue,
The surface of this substrate was subjected to A
Under a condition of r pressure of 1 mTorr, a 98 nm-thick alumina film serving as an antireflection film and an etching stopper 103 was formed. PECVD (Plasma Enhanced Chemical V) using SiH ₄ , NH ₃ , N ₂ O and gas as raw materials
The stress of the SiON film is reduced to almost zero by forming an 900 nm thick SiON film to be the patterning layer 104 by an apor deposition method and performing an annealing process after the film formation.
It was adjusted to MPa.

Next, as shown in FIG.
E device, using aluminum as an etching mask under the conditions of pressure of 10 mTorr and RF power of 200 W, C
An F ₄ gas of 25 sccm and an O ₂ gas of 40 sccm are supplied to remove an area with a radius of 70 mm at the center of the back surface,
An opening region 105 serving as a mask when etching was formed. Next, as shown in FIG. 27C, an outer diameter of 125 mm and an inner diameter of
A glass ring having a thickness of 6.2 mm and a thickness of 6.2 mm
As joined. Furthermore, by back etching equipment,
A one-to-one mixed solution of hydrofluoric acid and nitric acid was dropped into the portion where the SiC had been removed, and the Si was removed by etching.

Next, as shown in FIG. 27D, a commercially available positive resist for electron beam ZEP520 is formed on the substrate.
(Viscosity: 120 cps) by spinning at a rotation speed of 2000 rpm for 50 seconds, and using a hot plate for 175 times.
The photosensitive film 107 having a thickness of 300 nm was formed by performing a baking process at 2 ° C. for 2 minutes. Then, pattern writing was performed using an electron beam writing apparatus with an acceleration voltage of 75 kV. In order to obtain a desired drawing viscosity, the drawing is performed in a large amount to form a pattern by overwriting four times, and the reference irradiation amount is set to 96 μm.
As C / cm ² , proximity effect correction was performed by irradiation amount correction.

After drawing, a commercially available developing solution ZE was used as a developing process.
Development was performed using P-RD at a liquid temperature of 18 ° C. for 1 minute, followed by rinsing with MIBK for 1 minute to remove the developer. Then, using the formed resist pattern as a mask, the SiON film 104 was processed by reactive ion etching using CHF ₃ and CO gas. The remaining resist was removed by ashing in oxygen plasma, and then washed with a mixed solution of sulfuric acid and hydrogen peroxide.

Next, as shown in FIG.
Using a sputtering apparatus under a condition of an Ar pressure of 3 mTorr, copper (C
u) was formed. Subsequently, as shown in FIG.
A heat treatment was performed at 500 ° C. for 5 minutes in the same vacuum as the sputtering, and Cu was coagulated and embedded in the concave portions of the pattern.

[0320] Finally, the removal of excess Cu was performed by the following method called resist etch back. First, a commercially available electron beam resist, ZEP520 (viscosity: 12 cps), is spin-coated on the mask surface under the same conditions as those used for the previous resist coating under the conditions of a rotation speed of 2000 rpm and 50 seconds, and using a hot plate. A baking treatment was performed at 175 ° C. for 2 minutes to form a resist film 109 having a thickness of 300 nm as shown in FIG. At this time, due to the characteristics of spin coating, the surface has a substantially flat coating shape. Subsequently, as shown in FIG. 28D, the resist film 1 was formed by reactive ion etching using HBr gas.
09 and the etching rate of Cu are almost equal,
The mask surface was etched until the SiON surface was exposed.

Using the mask manufactured by the above process, a synchrotron radiation light source, a beam line provided with a mirror and a vacuum partition Be film, and an exposure light having a center wavelength of 0.8 nm were used to form a mask on a Si wafer. When the pattern was transferred to the applied resist, a pattern having a line width of 70 nm could be formed accurately.

It has been shown that a desired high-precision mask can be formed by the above method. And it turned out that the mask created by this method has the following advantages. First, the use of an SiON film facilitates stress control. SiON is easy to control the stress at the time of forming the film and has a temperature of 500.
Auger electron spectroscopy and Rutherford backscattering spectroscopy show that Cu does not diffuse into the SiON layer even after heat treatment at 1 ° C. for 1 hour, indicating that it is a suitable material for the permeable film pattern layer. Was done.

Therefore, even when the absorber is buried in the recess having a high aspect ratio, the heat treatment can be performed at a high temperature.
Embedding without heat dissipation and voids can be realized, and a highly accurate absorber pattern can be formed. Further, in the X-ray exposure mask in which the patterns of the X-ray absorber and the transmission film are formed on the membrane films formed in the fourteenth and fifteenth embodiments, the thickness of the absorber and the transmission film is equal and flat. Therefore, there is no foreign matter such as dust attached to the fine pattern recesses in the X-ray exposure mask in which only the absorber pattern is formed, and even if foreign matter such as dust adheres to the surface, Has the advantage that it can be removed only by washing.

The exposure mask was washed with pure water first, immersed in dissolved ozone water with an ozone concentration of 0.001% for 3 minutes, and then washed with a hydrofluoric acid aqueous solution with a hydrofluoric acid concentration of 5%. The organic matter on the surface is removed by immersion for 2 seconds, and finally, the substrate is washed with pure water to complete a series of processing. Contamination of the X-ray exposure mask due to foreign matter is an important problem in transfer exposure. If foreign matter adheres to the mask, the foreign matter is transferred to the wafer and causes a pattern defect. Therefore, it is necessary to avoid attaching foreign matter to the mask as much as possible. In particular, in exposure using X-rays, the transmittance of the X-ray substance is generally extremely low,
Even a very small foreign matter does not transmit X-rays and causes defects.

In an exposure method using visible or ultraviolet light, a pellicle formed of an organic thin film such as nitrocellulose or parylene is often attached to prevent foreign matter from adhering to a mask. Pellicles are generally not used because they have a large absorption of pellicle X-rays, greatly attenuate the intensity of exposure light, have low heat resistance, and have low irradiation resistance. Therefore, the X-ray exposure mask formed in the present embodiment has an advantage that foreign matter can be easily removed by simple cleaning, so that the mask cleaning and foreign matter removing steps can be performed at low cost,
Inexpensive semiconductor devices or optical elements can be supplied.

In this embodiment, an alloy of Cu and Zn, for example, brass can be used as the absorber instead of the Cu absorber. FIG. 36 and the following (Table 2)
As shown in 9), even in an X-ray exposure mask in which Cu ₇ Zn ₃ is combined with an SiO ₂ transmission film or an SiON transmission film, the phase shift amount with respect to the exposure light having a wavelength of 0.65 to 1.02 nm. Excellent controllability (dispersion within ± 8% within the exposure wavelength range)
It has a sufficient shielding property of 3.58 in nm. Therefore, Cu ₇
An X-ray exposure mask having a structure in which Z ₃ is embedded in a SiO ₂ permeable film or SiON permeable film pattern is made of Cu Si
As in the case of an X-ray exposure mask having a structure embedded in the ON transmission film pattern, exposure transfer with high resolution can be expected by using these masks.

[0327]

[Table 29]

The alloy of Cu and Zn is soft,
In the nanoimprint lithography method described in the fourth embodiment, since the pressing force is small and the melting point is low, the heat treatment temperature can be kept low. Also,
Here, excess Cu remaining on the flat portion is removed by a resist etching method, but the removal is easily performed by using a polishing apparatus for an object formed of a free-standing thin film such as an X-ray exposure mask. be able to.

(Sixteenth Embodiment) Next, a method for producing a micro device using an X-ray exposure mask manufactured by the above method will be described. Examples of the microdevice here include an integrated circuit, a semiconductor chip such as an ULSI, a liquid crystal device, a micromachine, a thin-film magnetic head, and the like. The following shows an example of a semiconductor device.

FIG. 37 is a diagram showing a processing flow of semiconductor device production. In 1-1 (circuit design), a circuit of a semiconductor device is designed using CAD or the like. In 1-2 (mask production), a mask on which a designed circuit pattern is formed is produced. On the other hand, in 1-3 (wafer manufacturing), a wafer is manufactured using a material such as silicon.

In 1-4 (wafer process), using the X-ray exposure mask and wafer prepared in the above-described embodiment and the like,
Lithography technology (pretreatment, resist coating, pre-bake, exposure, post-exposure bake (PEB), development / rinse, post-bake, etching, ion implantation,
An actual circuit pattern is formed on the wafer by a process such as resist stripping and inspection). The next 1-5 (assembly) is a post-process and a process of forming a semiconductor chip using the wafer prepared in 1-4, and includes an assembly process (dicing, bonding), a packaging process (chip process), and the like. Process. 1-6 (Inspection and repair)
Then, inspections and repairs such as an operation check test and a durability check test of the semiconductor device created in 1-5 are performed. Through these steps, a semiconductor device is completed and shipped.

According to the production method of this embodiment, it is possible to reduce the cost of the transfer exposure step by using a low-cost X-ray exposure mask, and to supply an inexpensive semiconductor device or optical element. Become.

[0333]

As described above in detail, according to the present invention, the maximum light intensity of light incident on the mask portion is set to a wavelength of 0.6 to 1 nm.
X using the synchrotron radiation emitted from the camera as the exposure light source
In X-ray exposure, it is possible to make the X-ray absorber thinner by using an X-ray absorber material having a large absorption in this exposure wavelength range, and to use a material having a controlled phase shift amount to transfer pattern. X-ray exposure masks having remarkable characteristics that the resolution of X-rays can be improved can be realized.

In manufacturing an X-ray exposure mask,
By adopting nanoimprint lithography technology, eliminating the peeling step and adding a heating step, it is possible to form a fine pattern with a high aspect ratio structure even for many metal materials, and manufacture high-precision various exposure masks Can be performed simply and at low cost. Furthermore, by using a low-cost X-ray exposure mask, the cost of the transfer exposure step can be reduced, and a low-cost semiconductor device or optical element can be supplied.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of an X-ray exposure mask according to the present invention.

FIG. 2 is a cross-sectional view (Da = Dt) showing the structure of the X-ray exposure mask of the present invention.

FIG. 3 is a cross-sectional view (Da <Dt) showing the structure of the X-ray exposure mask of the present invention.

FIG. 4 is a cross-sectional view (Da> Dt) showing the structure of the X-ray exposure mask of the present invention.

FIG. 5 is a diagram showing an intensity distribution of synchrotron radiation.

FIG. 6 is a view showing a structure of a conventional X-ray exposure mask and an exposure method.

FIG. 7 is a view showing the structure of a conventional X-ray exposure mask.

FIG. 8 is a view showing the structure of a conventional X-ray exposure mask.

FIG. 9 is a diagram showing absorption characteristics of Cu, Gd, Ta, W, and Au.

FIG. 10 is a diagram showing absorption characteristics and mask contrast of Gd _x Au _y .

FIG. 11: Ni, Cu, Ta, W, Au, Cu—SiO
Shows a _second phase characteristic.

FIG. 12 shows a group I (Co, Ni, Cu, Zn, G
The figure which shows the phase characteristic of a).

FIG. 13: Group II (Tc, Rh, Pd, Ag, T
The figure which shows the phase characteristic of e).

FIG. 14: Group III (La, Ce, Nd, Sm, E
The figure which shows the phase characteristic of u).

FIG. 15 shows a group IV (Ir, Pt, Au, Pb, F
The figure which shows the phase characteristic of r).

FIG. 16 is a diagram showing phase characteristics of Co, Ni, Cu, and Zn.

17 illustrates the phase characteristic and the mask contrast of Sm _x Au _y.

FIG. 18 is a diagram showing transmission characteristics of a Si ₃ N ₄ , SiC, Si, and diamond film.

FIG. 19: Mg, Al, Si, MgO, Al ₂ O ₃ , S
graph showing the transmission characteristics of the iO ₂ film.

FIG. 20: Ca, Sc, Ti, CaO, Sc ₂ O ₃ , T
graph showing the transmission characteristics of the iO ₂ film.

FIG. 21 is a view showing transmission characteristics of Sr, SrO, and SrF ₂ films.

FIG. 22 is a view showing transmission characteristics of Y, Zr, Y ₂ O ₃ , and ZrO ₂ films.

FIG. 23 is a diagram showing phase characteristics in an Au absorber and various permeable membrane embedded structures.

FIG. 24 is a diagram showing phase characteristics in a Cu absorber and various permeable film embedded structures.

FIG. 25 is a view showing phase characteristics in a Ni absorber and various permeable film embedded structures.

FIG. 26 is a diagram showing a configuration of an X-ray exposure apparatus according to an eleventh embodiment.

FIG. 27 is a sectional view showing a manufacturing step of the X-ray exposure mask according to the twelfth embodiment.

FIG. 28 is a cross-sectional view showing a step of manufacturing the X-ray exposure mask according to the twelfth embodiment.

FIG. 29 is a view for explaining effects according to the twelfth embodiment;

FIG. 30 is a sectional view for explaining a polishing apparatus according to a thirteenth embodiment;

FIG. 31 is a sectional view showing a manufacturing step of the X-ray exposure mask used in the fourteenth embodiment.

FIG. 32 is a cross-sectional view showing a step of manufacturing the X-ray exposure mask used in the fourteenth embodiment.

FIG. 33 is a process sectional view showing a modification of the fourteenth embodiment;

FIG. 34 is a view showing X-ray transmission characteristics of a SiON film and a SiO ₂ film.

FIG. 35 is a view showing the wavelength dependence of the phase shift amount and the exposure light intensity in two X-ray exposure masks.

FIG. 36: Cu and CuZn absorber, SiON and Si
FIG. 4 is a diagram illustrating the wavelength dependence of the amount of phase shift of an X-ray exposure mask made of an O ₂ transmission film.

FIG. 37 is a view showing a processing flow of semiconductor device production according to the sixteenth embodiment;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... X-ray exposure mask 2 ... Resist 3 ... Substrate 4 ... X-ray (synchrotron radiation) 5 ... Pattern made of the absorber material according to the present invention 5 '... Absorber material in a conventional example 6 ... Membrane (support film) 7) Support frame 8 ... Pattern made of permeable membrane material according to the present invention 8 '... First permeable membrane according to the present invention 8 "... Second permeable membrane according to the present invention 10 ... Resin or silicon dioxide pattern 14 ... Synchrotron radiation light source 22 Condensing mirror 23 Oscillating mirror 24 Diamond window 25 Beryllium window 26 Silicon nitride window 27 X-ray exposure mask 28 Stepper 29 Wafer 101 Film forming substrate (Si wafer) 102 ... X-ray transparent thin film (SiC) 103 ... Anti-reflection film and etching stopper (Al
₂ O ₃ ) 104 patterning layer (SiO ₂ ) 105 opening area 106 frame 107 resist (photosensitive film) 108 absorber (Cu) 109 resist 110 opening 211 polishing platen 212 polishing pad 213 ... Abrasive 214 ... Abrasive tank 215 ... Supply control mechanism 216 ... Abrasive supply pipe 217 ... Mask 218 ... O-ring 219 ... Pedestal 220 ... Clamp 221 ... Pressure adjusting fluid (pure water) 222 ... Inflow pipe 223 ... Outflow pipe 224 pressure gauge 225a, b flow rate adjustment mechanism 226 constant temperature device 227 sensor 228 control computer 229 volume deformable mechanism

Claims (15)

[Claims] 1. An X-ray exposure mask comprising: an X-ray mask having a pattern formed of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask. The maximum light intensity of the light incident on the mask portion is set to a wavelength of 0.1.
Synchrotron radiation having a wavelength of 6-1 nm is used as an exposure light source, and the X-ray absorber material has a density / atomic weight of 0.0
85 is a [g / cm ^3] or more, and elements having an L-shell absorption edge in the wavelength 0.75～1.6Nm, or density / atomic weight 0.04 [g / cm ^3] or more, and M shells An X-ray exposure mask comprising an element having an absorption edge at a wavelength of 0.75 to 1.6 nm. 2. The X-ray absorber material comprises Co, Ni, C
u, Zn, Ga, La, Ce, Pr, Nd, Pm, S
m, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb
2. The X-ray exposure mask according to claim 1, further comprising at least one element selected from the group consisting of: 3. An X-ray exposure mask comprising: an X-ray mask having a pattern of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask. The maximum light intensity of light incident on the mask part is 0.6 to
A synchrotron radiation having a wavelength of 1 nm is used as an exposure light source, and the X-ray absorber is a first element made of any one of elemental elements having an L-shell absorption edge or an M-shell absorption edge at a wavelength of 0.75 to 1.6 nm. The material and the M-shell absorption edge have a wavelength of 0.5 to 0.75.
with a second material consisting of any of the elementary elements having
An X-ray exposure mask, which is an alloy or a laminated film. 4. An X-ray exposure mask comprising: an X-ray mask having a pattern formed of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask. As an absorber, all L-shell and M-shell absorption edges are:
Exposure wavelength region of synchrotron radiation light as an exposure light source (a wavelength region having an intensity of 1/10 or more of the light intensity at the wavelength of the maximum light intensity incident on the X-ray mask portion as the light intensity is defined as an exposure wavelength region). An X-ray exposure mask, characterized by using a material containing an element as a main component, which is a region of not more than the shortest wavelength or not less than the longest wavelength of the exposure wavelength. 5. The X-ray absorber material comprises Ti, V, Cr,
Mn, Fe, Co, Ni, Cu, Zn, Nb, Mo, T
c, Ru, Rh, Pd, Ag, La, Ce, Pr, N
The X-ray exposure mask according to claim 4, further comprising at least one element selected from the group consisting of d, Pm, Sm, Eu, and Gd. 6. An X-ray exposure mask comprising: an X-ray mask portion having a pattern formed of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask portion. The maximum light intensity wavelength of light incident on the mask portion is set to 0.
Synchrotron radiation having a wavelength of 6 to 1 nm is used as an exposure light source, and all of the L shell and M are used as the X-ray absorber.
An X-ray exposure mask using a material whose main component is an element having a shell absorption edge of 0.65 nm or less or 1.02 nm or more. 7. An X-ray exposure mask comprising: an X-ray mask portion having a pattern made of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask portion. As an absorber, all L-shell and M-shell absorption edges are:
Exposure wavelength region of synchrotron radiation light as an exposure light source (a wavelength region having an intensity of 1/10 or more of the light intensity at the wavelength of the maximum light intensity incident on the X-ray exposure mask is defined as the exposure wavelength region. A) the first material whose wavelength is equal to or less than the shortest wavelength or equal to or greater than the longest wavelength of the exposure wavelength, and wherein any one absorption edge is in a wavelength range from the shortest wavelength of the exposure wavelength range to a wavelength 0.4 nm shorter than the shortest wavelength. And all the L-shell and M-shell absorption edges are in the region not longer than the shortest wavelength of the exposure wavelength region of the synchrotron radiation light as the exposure light source or not shorter than the longest wavelength of the exposure wavelength, and one of the absorption edges is exposed. An X-ray exposure mask using an alloy or a laminated film in which a second material in a wavelength range from the longest wavelength to a wavelength 0.6 nm longer than the longest wavelength is combined. 8. An X-ray exposure mask comprising an X-ray mask having a pattern formed of an X-ray absorber formed on a membrane film, and a support for supporting the X-ray mask, comprising: (A wavelength region having an intensity of 1/10 or more of the light intensity at the wavelength of the maximum light intensity incident on the X-ray exposure mask as the light intensity) is set to an exposure wavelength range of 0.65 nm to 1.02 nm. Using the synchrotron radiation light having as an exposure light source, as the X-ray absorber, all L-shell and M-shell absorption edges,
A first wavelength in a wavelength range from the shortest wavelength or less to the longest wavelength or more in the exposure wavelength range, and any one absorption edge is in a wavelength range from the shortest wavelength in the exposure wavelength range to a wavelength 0.4 nm shorter than the shortest wavelength. The material and all of the L-shell and M-shell absorption edges are in the region below the shortest wavelength or above the longest wavelength of the exposure wavelength, and any one absorption edge is from the longest wavelength of the exposure wavelength region to 0. An X-ray exposure mask using an alloy or a stacked film in combination with a second material having a wavelength range up to 6 nm longer. 9. An X-ray exposure mask comprising: an X-ray mask having a pattern formed of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask. An X-ray exposure mask having a transparent film pattern different from the X-ray absorber pattern thereon. 10. An X-ray exposure mask comprising: an X-ray mask portion having a pattern formed of an X-ray absorber formed on a membrane film; and a support for supporting the X-ray mask portion. When a wavelength region having an intensity of 1/10 or more of the light intensity at the wavelength of the maximum light intensity of the light incident on the mask portion is defined as an exposure wavelength region, the X-ray absorber material has a phase with respect to a wavelength within the exposure wavelength region. The maximum and minimum phase shift amounts are ± 10 of the average phase shift amount within the exposure wavelength range.
%. A mask for X-ray exposure characterized by using an X-ray exposure mask having a ratio of less than 10%. 11. The method for manufacturing an X-ray exposure mask for manufacturing an X-ray exposure mask according to claim 9, wherein said transmitting film pattern is formed on said membrane film, and said X-ray absorption is performed. A method for manufacturing an X-ray exposure mask, comprising: a step of depositing a body by a sputtering method or a chemical vapor deposition method; and a step of subsequently performing a heat treatment. 12. The method for manufacturing an X-ray exposure mask for manufacturing an X-ray exposure mask according to claim 9, wherein the step of forming the X-ray absorber pattern on the membrane film and the step of transmitting the X-ray light are performed. A method for manufacturing an X-ray exposure mask, comprising: a step of depositing a film by a sputtering method or a chemical vapor deposition method; and a step of subsequently performing a heat treatment. 13. A step of forming a first layer made of a substance different from an X-ray absorber on an X-ray transparent thin film, a step of forming a desired pattern on the first layer, and a step of forming the X-ray transparent thin film. And forming an X-ray absorber layer on the first layer;
Forming a second layer on the X-ray absorber layer to flatten the surface thereof, and simultaneously processing the X-ray absorber layer and the second layer. Manufacturing method of mask. 14. An X-ray exposure mask according to any one of claims 1 to 10, and an X-ray for irradiating the mask with synchrotron radiation having a maximum light intensity of 0.6 to 1 nm. A pattern exposure apparatus comprising: a source; and a unit configured to project and expose the X-ray transmitted through the mask onto a wafer. 15. A synchrotron radiation using the mask for X-ray exposure according to claim 1 and further having a maximum light intensity of light incident on said X-ray mask portion at a wavelength of 0.6 to 1 nm. A pattern exposure method comprising exposing and transferring a pattern formed on the mask onto a wafer using light as an exposure light source.