JPH0764271A - Halftone type phase shift mask blank and halftone type phase shift mask - Google Patents

Abstract

PURPOSE:To prevent the electrification by charge accumulation and static electricity at the time of electron beam plotting with simple film constitution by providing the surface of a transparent substrate with a specific translucent film in a single layer form for the purpose of forming light transparent parts. CONSTITUTION:This halftone type phase shift mask blank is constituted by forming the translucent film 2a on the transparent substrate 1 and this halftone type phase shift mask is constituted by subjecting the translucent film 2a of the halftone type phase shift mask blank to a patterning treatment to remove a part along the prescribed patterns to form the mask patterns composed of the light translucent parts 2 and the light transparent parts 3. The transparent substrate 1 is a quartz glass substrate subjected to mirror polishing on its main surface. Such translucent film 2a of the single layer form has a property to allow the transmission of light of the intensity not substantially contributing to exposing and a property to shift the phase of the exposing light by a prescribed quantity and simultaneously has an electric conductivity to the extent of not electrifying the charges or above at the time of electron plotting in combination.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention In the present invention, a mask pattern is composed of a light transmitting portion and a light semi-transmitting portion, and the phases of the light passing through the two are made different from each other so that the light passing near these boundaries cancels each other. The present invention relates to a halftone type phase shift mask blank and a halftone type phase shift mask, which are materials of a halftone type phase shift mass mask for improving the contrast of a boundary portion.

[0002]

2. Description of the Related Art In the manufacture of semiconductor LSIs, a phase shift mask is used as one of photomasks for transferring fine patterns. One of the phase shift masks is a halftone phase shift mask disclosed in, for example, Japanese Patent Application Laid-Open No. 5-127361, which is suitable for transferring a single hole, dot, line, space, or other isolated pattern. Masks are known.

The halftone type phase shift mask described in this publication has a mask pattern formed on the surface of a transparent substrate, and a light transmitting portion for transmitting light having an intensity that substantially contributes to exposure, and substantially contributes to exposure. And a light semi-transmissive portion that transmits light of a non-intensity, and the phase of light passing through the light semi-transmissive portion and the phase of light passing through the light transmissive portion are 180 °.
By shifting, the lights passing through the vicinity of the boundary between the light transmitting portion and the light semi-transmitting portion cancel each other so that the contrast of the boundary portion can be maintained well.

In this case, the light-semitransmissive film forming the light-semitransmissive portion is composed of a single layer of a material having a substantially uniform composition. That is, CrOx deposited with a target of chromium and a gas such as oxygen in the vapor deposition atmosphere,
It is composed of a film of CrNx, CrOx Ny, CrOx Ny Cz, or the like, or a film made of a material in which a pigment or dye is dispersed in a transparent inorganic or organic material (for example, spin-on-glass (SOG)).

By using the light-semitransmissive portion composed of a single layer film, the light-semitransmissive portion is made of a plurality of kinds of materials including a high transmittance layer (for example, SOG) and a low transmittance layer (for example, chromium). Compared with a halftone type phase shift mask having a multi-layer structure made of, it has advantages that the number of manufacturing steps is reduced and the occurrence of defects is suppressed. In particular, the light semi-transmissive film using chromium such as CrOx has an advantage that the etching selection ratio with the transparent substrate (glass) is higher than that of SOG, and it is not necessary to provide an etching stop layer.

The CrOx, CrNx, CrOx Ny,
Alternatively, regarding the method of forming the light semi-transmissive film made of CrOx Ny Cz or the like, in the above publication, chromium is used as a sputtering target and a gas such as oxygen is introduced into the vapor deposition atmosphere to deposit chromium oxide or nitride on the transparent substrate. There is disclosed a method of depositing a substance, an oxynitride, and an oxynitride carbide, that is, a method by so-called reactive sputtering.

[0007]

However, the light-semitransmissive film made of the material in which the pigment or the dye is dispersed in the above SOG is electrically insulating, and the above-mentioned conventional method (reactive sputtering method) is used. Formed by CrOx, C
The light semi-transmissive film made of rNx, CrOx Ny, CrOx Ny Cz or the like has a property of transmitting light that does not contribute to exposure, that is, the transmittance for exposure light is 4 to 20.
%, And the requirement for the light semi-transmissive portion to give a predetermined phase difference at the same time has poor conductivity. For this reason, there is a problem in that the electron implanted by the electron beam drawing on the resist for patterning the resist when etching the light semi-transmissive film is charged, and the pattern cannot be accurately formed.

Further, there is a problem that dust is easily adsorbed during the mask manufacturing process and during use due to electrostatic charging. Therefore, in order to prevent the charging phenomenon, it is necessary to provide a conductive layer that conducts and diffuses electricity on, for example, a transparent substrate, which has a drawback that the number of manufacturing steps is increased.

Furthermore, when a conductive film is formed between the transparent substrate and the light semi-transmissive film, it must be transparent to exposure light having a short wavelength, and for example, a high resolution pattern in recent years is required. For shorter wavelength of exposure light
There is also a problem in that a conductive layer material that is transparent to such exposure light must be newly developed.

The present invention has been made under the above-mentioned background, and is a halftone type phase shift mask blank and a halftone type which can prevent charge accumulation and static charge at the time of electron beam drawing by a simple film structure. The purpose is to provide a phase shift mask.

[0011]

In order to solve the above-mentioned problems, a method of manufacturing a halftone type phase shift mask blank according to the present invention comprises: (Structure 1) A mask for performing fine pattern exposure, which is transparent. The mask pattern to be formed on the surface of the substrate
Light consisting of a light-transmitting portion that transmits light of intensity that substantially contributes to exposure and a light-semitransmissive portion that transmits light of intensity that does not substantially contribute to exposure, and light that has passed through this light-semitransmitting portion. By making the phase of the light and the phase of the light passing through the light transmitting portion different from each other, the light passing through the vicinity of the boundary between the light transmitting portion and the light semi-transmissive portion cancels each other and the contrast of the boundary portion is improved. In the halftone type phase shift mask blank used as a material when manufacturing the halftone type phase shift mask that can be held well,
It has a single-layer light-semitransmissive film for forming the light-transmissive portion on a transparent substrate, and the light-semitransmissive film has a property of transmitting light having an intensity that does not substantially contribute to exposure and exposure light. A structure having a property of shifting a phase by a predetermined amount, and at the same time having a conductivity higher than a level at which electric charges are not charged at the time of drawing an electron beam.
As an aspect of (Structure 2), in the halftone phase shift mask blank of Structure 1, the sheet resistance, which is a surface resistance of 1 cm ² of the light-semitransmissive film, is 5 × 10 ⁷ Ω or less. In the halftone phase shift mask blank of the configuration 1 or 2, the transmittance of the light-semitransmissive film with respect to the exposure light is 4 to 20%. (Configuration 4) In the halftone phase shift mask blank according to any one of Configurations 1 to 3, the light-semitransmissive film contains SnOx. (Configuration 5) In the halftone phase shift mask blank according to any one of Configurations 1 to 3, the light semitransmissive film is trivalent or 5 At least one element that can have a valence charge
A constitution comprising an amorphous silicon film containing a seed, and (Constitution 6) In the halftone phase shift mask blank according to any one of constitutions 1 to 3, the light semi-transmissive film is silicon carbide (Six C). In the halftone type phase shift mask blank of the constitution 6, the X of silicon carbide (Six C) is formed.
The value of is 0.8 ≦ X ≦ 10. (Structure 8) In the halftone phase shift mask blank according to any one of Structures 1 to 3, the light-semitransmissive film is chromium. A halftone phase shift mask according to the present invention, wherein the halftone type phase shift mask according to the present invention is made of a material containing chromium and oxygen and having an atomic ratio of chromium to oxygen (Cr / O) of 0.3 or more. (Structure 9) A mask for performing fine pattern exposure, comprising a mask pattern formed on the surface of a transparent substrate,
Light consisting of a light-transmitting portion that transmits light of intensity that substantially contributes to exposure and a light-semitransmissive portion that transmits light of intensity that does not substantially contribute to exposure, and light that has passed through this light-semitransmitting portion. By making the phase of the light and the phase of the light passing through the light transmitting portion different from each other, the light passing through the vicinity of the boundary between the light transmitting portion and the light semi-transmissive portion cancels each other and the contrast of the boundary portion is improved. 9. A halftone type phase shift mask which can be held satisfactorily.
The light-semitransmissive film of the phase shift mask blank according to any one of 1 to 3, is subjected to a patterning process of partially removing according to a predetermined pattern, to form a mask pattern consisting of a light-transmissive portion and a light-semitransmissive portion. The configuration is characterized by.

[0012]

According to the above configuration 1, the single-layered light semi-transmissive film for forming the light transmissive portion is provided, and the light semi-transmissive film is
It has the property of transmitting light of an intensity that does not substantially contribute to the exposure and the property of shifting the phase of the exposure light by a predetermined amount, and at the same time, has the conductivity of a level at which electric charges are not charged during electron beam drawing. Therefore, the simple film structure makes it possible to prevent charge accumulation and electrostatic charge during electron beam writing.

According to the structure 2, the sheet (surface) resistance of the light semi-transmissive film is set to 5 × 10 ⁷ Ω or less,
It is possible to reliably prevent charge accumulation and electrostatic charging during electron beam writing.

Further, according to the structure 3, it is possible to obtain a light semi-transmissive film having an excellent light transmittance.

Further, according to the structure 4, the light semi-transmissive film is made of Sn.
By using a material containing Ox, in particular, when the wavelength of the exposure light is 248 nm, it provides a predetermined light transmittance and phase shift performance, and at the same time, has conductivity that effectively suppresses the accumulation of electric charges. Therefore, charging can be prevented.

Further, according to the structure 5, the light semi-transmissive film is 3
Since it is an amorphous silicon film containing at least one element having a valence or pentavalent charge, it should have a predetermined transmittance, light-shielding performance and conductivity, especially when the exposure light wavelength is 365 nm or 248 nm. It becomes possible.

According to the configurations 6 and 7, since the light semi-transmissive film is made of Six C (0.8≤X≤10), the light semi-transmissive film has a predetermined transmission at a wavelength of 248 nm. It becomes possible to have a rate, a light shielding performance, and conductivity.

Further, according to the structure 8, the light semi-transmissive film is
It contains chromium and oxygen, and the atomic ratio of chromium and oxygen (Cr
/ O) is 0.3 or more,
This makes it possible to relatively easily manufacture a light-semitransmissive film having desired transmittance, light-shielding performance, and conductivity. In addition, Cr /
If O is less than 0.3, the desired conductivity cannot be obtained.

According to the structure 9, a phase shift mask using the halftone type phase shift mask blanks of structures 1 to 8 can be obtained.

[0020]

【Example】

(Embodiment 1) FIG. 1 is a diagram showing a halftone type phase shift mask blank and a halftone type phase shift mask according to Example 1, and FIG. 1A is a sectional view showing the halftone type phase shift mask blank. FIG. 1B is a sectional view showing a halftone phase shift mask.

As shown in FIG. 1A, the halftone type phase shift mask blank has a light semitransmissive film 2a formed on a transparent substrate 1. Further, as shown in FIG. 1B, the halftone type phase shift mask is formed on the light semitransmissive film 2a of the halftone type phase shift mask blank shown in FIG. 1A along a predetermined pattern. A mask pattern composed of the light semi-transmissive portion 2 and the light transmissive portion 3 is formed by performing a patterning process for removing a portion.

The transparent substrate 1 is a quartz glass substrate whose main surface is mirror-polished.

The light semi-transmissive film 2 is made of antimony (Sb) -containing tin oxide (SnOx). In this embodiment, the exposure light is KrF excimer laser light (wavelength λ = 24).
8 nm), Sb is set to 2 m so that the light semi-transmissive portion 2 can simultaneously obtain a predetermined phase shift amount, a predetermined light shielding performance, and a predetermined conductive performance with respect to this exposure light.
ol% and the oxygen content is SnO ₂ (2 mol of Sb-containing SnO ₂ ; refractive index 2.
0), the transmittance was set to 13% when λ = 248 nm by setting the film thickness to 1240 Å.

In this case, when the phase shift amount is φ, the refractive index is n, and the wavelength of the exposure light is λ, the film thickness d is determined by the following equation (1).

D = (φ / 360) × {λ / (n−1)} (1) In equation (1), the phase shift amount φ is preferably 180 °, but practically 160 It suffices if it is ° ≦ φ ≦ 200 °.

The light transmissivity of the light semi-transmissive portion 2 with respect to the exposure light depends on the sensitivity of the resist used for pattern formation, but is generally about 4 to 20%, but 5
It is desirable to be set to -15%. When the light transmittance is 4% or less, a sufficient canceling effect of light passing through the boundary between the light semi-transmissive portion 2 and the light transmissive portion 3 cannot be obtained, and when the light transmittance is 20% or more, the light semi-transmissive portion. The light passing through 2 may also expose the resist. The light transmittance of the light semi-transmissive portion 2 can be selected by selecting the oxidation degree of tin oxide and the content ratio of antimony. Further, the conductive property of the light transmitting portion 2 is preferably 5 × 10 ⁷ Ω or less. The reason for this is that if the resistance is 5 × 10 ⁷ Ω or more, it is difficult to sufficiently conduct the electrons driven by the electron beam irradiation. In order to obtain this conductive performance, it can be selected by selecting the content rates of tin oxide and antimony. In this case, if the oxidation degree of SnOx is increased or the content of Sb is increased, the light transmittance is increased. Further, if the content of Sb is increased, the conductivity is also increased at the same time. However, if Sb is 5 mol% or more, S
On the other hand, b is deposited and the conductivity is reduced.

Next, a procedure for manufacturing the above-mentioned phase shift mask will be described with reference to FIG.

First, a light-semitransmissive film 2a made of SnO ₂ containing 2 molSb having a film thickness of 1240 angstrom is formed on the surface of the transparent substrate 1 to obtain a phase shift mask blank (see FIG. 2A).

The formation of the light-semitransmissive film 2a is performed by sputtering using Sb-containing Sn as a target in an oxygen atmosphere. As another forming method, the film may be formed by an EB vapor deposition method using an Sb-containing SnO ₂ tablet.

Next, an electron beam resist film 4a (C manufactured by Tosoh Corp.) is formed on the light semi-transmissive film 2a of this phase shift mask blank.
MS-M8) is formed to a thickness of 6000 angstroms (see FIG. 2B), irradiated with an electron beam along a predetermined pattern, and then developed to form a resist pattern 3 (FIG. 2C). )reference).

Next, the light semi-transmissive film 2a is dry-etched along the resist pattern 4 by using a reactive dry etching (RIE) parallel plate type dry etching apparatus under the following conditions (FIG. 2 (d)). reference).

Etching gas: CH3 OH RF power: 700 W Gas pressure: 0.11 Torr Electrode temperature: 80 ° C. Then, by removing the remaining resist pattern,
A phase shift mask having the light semi-transmissive portion 2 and the light transmissive portion 3 is obtained (see FIG. 2E).

As shown in FIG. 3, this phase shift mask receives the exposure light L0 when it is irradiated with the exposure light L0.
Is a light L1 that passes through the light semi-transmissive portion 2 and reaches a transfer target (not shown), and a light L that passes through the light transmission portion 3 and reaches the transfer target.
Divide into 2. In this case, the light L that has passed through the light semi-transmissive portion 2
An intensity of 1 is weak light that does not substantially contribute to the exposure. On the other hand, the light L2 that has passed through the light transmitting portion 3 is a strong light that substantially contributes to the exposure. So this gives
Pattern exposure is performed. At that time, the light passing through the boundary between the light semi-transmissive portion 2 and the light transmissive portion 3 wraps around to the other area due to the diffraction phenomenon, but the phases of the two light beams are substantially inverted, and thus they are canceled by each other. . by this,
The boundaries are very clear and the resolution is improved.

According to the first embodiment described above, the light semi-transmissive film 2a is formed.
Has a sheet resistance of 1.6 × 10 ³ Ω, and sufficiently prevents electrons hit by electron beam irradiation for forming a resist pattern for etching the light semi-transmissive film 2a from being charged. It was possible.

Further, the light semi-transmissive film 2a of this embodiment has an etching selection ratio (etching rate of the light semi-transmissive film / etching rate of the transparent substrate) of 11 with respect to the transparent substrate 1 and almost damages the transparent substrate. The light semi-transmissive film 2a can be etched without the need.

Further, since the light semi-transmissive film 2a (light semi-transmissive portion 2) of this embodiment has sufficient adhesive force with the transparent substrate, it is suitable for ultrasonic cleaning which is carried out in the usual photomask cleaning process. SnO ₂ that can withstand and has excellent acid resistance
Since it is excellent in acid resistance because it contains as a main component, it was able to withstand the sulfuric acid cleaning performed in the usual photomask cleaning step.

Further, as shown in FIG. 4, since the transmittance in the visible region is high, there is also an advantage that alignment can be easily performed.

When this phase shift mask was used, a depth of focus equivalent to that of the conventional phase shift mask was obtained.

(Example 2) In the halftone type phase shift mask blank and the halftone type phase shift mask of Example 2, the light semi-transmissive portion 2 and the light semi-transmissive film 2a in Example 1 were changed as follows. It is a thing.

In the second embodiment, the light semi-transmissive portion 2 and the light semi-transmissive film 2a are made of tin oxide + isodium oxide (SnOx +).
InOx; ITO) and the wavelength of exposure light λ = 248 nm
On the other hand, in order for the light semi-transmissive portion to obtain a predetermined amount of phase shift, a predetermined light shielding performance, and a predetermined conductivity at the same time, a mixed composition target of SnO ₂ 90 wt% + InO ₂ 10 wt% is set in an oxygen atmosphere. A film (refractive index: 2.0) obtained by sputtering was used, and the film thickness was 1240 angstrom. At that time, the transmittance at λ = 248 nm was 12%.

The light transmittance of the light semi-transmissive portion 2 can be selected by selecting the mixing ratio of tin oxide and indium oxide and the degree of oxidation of these oxides. Further, in order to obtain the conductive performance, it can be selected by selecting the content rates of tin oxide and indium oxide. In this case, increase the degree of oxidation of SnOx, InOx, or
Increasing the content of InOx increases the light transmittance of the light semi-transmissive film 2a. Also, increasing the InOx content simultaneously increases the conductivity. However, since InOx has poor acid resistance, if InOx is unduly spoiled, it tends to be deteriorated by cleaning. In the case of this embodiment, considering the acid resistance of the light semitransmissive film 2a, the content of tin oxide (SnOx) is 60 w.
It is preferably t% or more.

According to the second embodiment described above, the light semi-transmissive film 2a is formed.
Has a sheet resistance of 1.8 × 10 ² Ω, and sufficiently prevents electrons hit by the electron beam irradiation for forming a resist pattern for etching the light semi-transmissive film 2a from being sufficiently charged. It was possible. Further, the light semi-transmissive film 2a of the present embodiment can be dry-etched by the reactive dry etching method using a magnetron type dry etching apparatus under the following conditions. Etching selectivity is 1
4 and the light semi-transmissive film 2 without damaging the transparent substrate 1.
It was possible to perform etching of a.

Etching gas: CH4 + H2 + Cl2 RF power: 500 W Gas pressure: 0.02 Torr Electrode temperature: 60 ° C. Further, the light semi-transmissive film 2a (light semi-transmissive portion 2) of this embodiment is
Sufficient adhesion to the transparent substrate is obtained, so it can withstand the ultrasonic cleaning that is performed in the normal photomask cleaning process. Furthermore, SnO ₂ that has excellent acid resistance is used as the main component, making it acid resistant. Since it was excellent, it could withstand the sulfuric acid cleaning performed in the usual photomask cleaning process.

Further, similarly to the first embodiment, since the transmittance in the visible range is high, there is also an advantage that alignment can be easily performed.

When this halftone type phase shift mask was used, the same depth of focus as that of the conventional halftone type phase shift mask was obtained.

(Example 3) In the halftone type phase shift mask blank and the halftone type phase shift mask of Example 3, the light semi-transmissive portion 2 and the light semi-transmissive film 2a in Example 1 were changed as follows. It is a thing.

In Example 3, the light semi-transmissive portion 2 and the light semi-transmissive film 2a were made of tin oxide (SnOx), and the light semi-transmissive film 2a was formed by the following steps.

First, 100 g of Sn-butoxide was added to 3 g of pure water.
0 ml was added for hydrolysis, and further adjusted with a predetermined mixed organic solvent to obtain a coating liquid. Then, the coating solution is spin-coated on a transparent substrate and further heat-treated at 400 ° C. in an oxygen atmosphere to form a light semi-transmissive film 2a (refractive index 2.1, film thickness 1125) made of SnOx (X is about 1.95). Angstrom). The light transmittance of the light semi-transmissive film 2a at the wavelength λ = 248 nm was 15%.

The light transmittance of the light semi-transmissive film 2a can be selected by selecting the oxidation degree of tin oxide.
Further, in order to obtain the desired conductive performance, it is possible to select by similarly selecting the oxidation degree of tin oxide and depleting oxygen. In this case, oxygen deficiency can be created by making X of SnOx slightly smaller than 2. Further, if the oxidation degree of SnOx is increased, the transmittance can be increased, but conversely the conductivity is decreased. In order to increase the conductivity, it is necessary to reduce X within a range in which the light transmittance can be maintained within a required range. However, if X is too small than 2, a film defect may occur. It is necessary to pay.

According to the third embodiment described above, the light semi-transmissive film 2a is formed.
Has a sheet resistance of 4 × 10 ⁴ Ω and is capable of sufficiently preventing charging of electrons hit by electron beam irradiation for forming a resist pattern for etching the light semi-transmissive film 2a. Met.

Further, the light semi-transmissive film 2a of this embodiment can be etched by using a reactive dry etching (RIE) parallel plate type dry etching apparatus under the following conditions. At this time, the etching selection ratio to the transparent substrate 1 was 12, and the light semitransmissive film 2a could be etched without damaging the transparent substrate 1.

Etching gas: C ₂ H ₅ OH RF power: 1000 W Gas pressure: 0.07 Torr Electrode temperature: 100 ° C. Further, the light semi-transmissive film 2a (light semi-transmissive portion 2) of this embodiment is
Since sufficient adhesion to the transparent substrate 1 can be obtained, SnOx (X is approximately 1.) that can withstand ultrasonic cleaning performed in a normal photomask cleaning process and has excellent acid resistance.
Since it is composed of 95), it is excellent in acid resistance, and therefore can withstand the sulfuric acid cleaning carried out in the usual photomask cleaning step.

Further, as in the first embodiment, since the transmittance in the visible range is high, there is also an advantage that alignment can be easily performed.

When this halftone type phase shift mask was used, the depth of focus equivalent to that of the conventional halftone type phase shift mask was obtained.

(Example 4) In the halftone type phase shift mask blank and the halftone type phase shift mask of Example 4, the light semi-transmissive portion 2 and the light semi-transmissive film 2a of Example 1 were changed as follows. It is a thing.

In the fourth embodiment, the light semi-transmissive portion 2 and the light semi-transmissive film 2a are made of hydrogen (H) and fluorine (F) -containing amorphous silicon (α-Si: α-Si:
F: H) and was formed by the following steps.

SiF ₄ 30 sccm, H ₂ 25 scc
A P-containing amorphous Si: F: H film (refractive index 5.9, film thickness 370 angstrom) was obtained by plasma CVD using m, TMP (trimethylphosphalas) 2 sccm as a gas source. In this embodiment, the i-line (wavelength λ = 365) of the mercury lamp of the light semi-transmissive portion 2 and the light semi-transmissive film 2a is used.
(nm) was 8% for the exposure light.

The light transmittance of the light semi-transmissive portion 2 can be selected by selecting the contents of hydrogen and fluorine. In this case, the transmittance can be increased by increasing the contents of F and H (particularly the effect of F is large), while the conductivity can be increased by increasing the content of P. Since P has a small content, it hardly affects the transmittance.
Further, it is sufficient that F and H include at least one of them.

According to the fourth embodiment, the electroconductivity of the light semi-transmissive film 2a is such that the sheet resistance is 1.5 × 10 ⁴ Ω, and the electron beam used for forming the resist pattern for etching the light semi-transmissive film. It was possible to sufficiently prevent the electrons and static electricity driven by the irradiation from being charged.

Further, the light semi-transmissive film 2a of the present embodiment can be etched by using a reactive dry etching (RIE) parallel plate type dry etching apparatus under the following conditions. The etching selection ratio to the transparent substrate was 25, and the light semitransmissive film 2a could be etched without damaging the transparent substrate 1.

Etching gas: SiCl ₄ RF power: 1000 W Gas pressure: 0.07 Torr Electrode temperature: 20 ° C. Further, the light semi-transmissive film 2a (light semi-transmissive portion 2) of this embodiment is
Since sufficient adhesion to the transparent substrate 1 can be obtained, it can withstand ultrasonic cleaning performed in a normal photomask cleaning process, and since it has excellent acid resistance, it can be used in a normal photomask cleaning process. It was able to withstand the sulfuric acid cleaning performed.

Further, it was confirmed that the light semi-transmissive portion 2 of the present example is excellent in thermal stability and there is no possibility of causing a change in the film characteristics when heat is applied in the washing process.

When this halftone type phase shift mask was used, the same depth of focus as that of the conventional halftone type phase shift mask was obtained.

Example 5 In the halftone type phase shift mask blank and the halftone type phase shift mask of Example 5, the light semi-transmissive portion 2 and the light semi-transmissive film 2a in Example 1 were changed as follows. It is a thing.

In the fifth embodiment, the light semi-transmissive portion 2 and the light semi-transmissive film 2a are made of fluorine (F) doped with boron (B).
Containing amorphous silicon (α-Si: F),
It was formed by the following steps.

Sputtering was performed in a fluorine atmosphere using a Si target containing 0.1% by weight of boron to obtain a B-doped α-Si: F film (refractive index 6.1, film thickness 358 Å). . In this example, the light transmittance of the mercury lamp for the i-line (wavelength λ = 365 nm) exposure light was 8%.

The light transmittance of the light semi-transmissive portion 2 can be selected by selecting the content of fluorine. Also,
In order to obtain conductive performance, it can be selected by selecting the content of boron. In this case, the transmittance can be increased by increasing the F content, while the conductivity can be increased by increasing the B content.

According to the fifth embodiment described above, the light semi-transmissive film 2a is formed.
Has a sheet resistance of 1.2 × 10 ⁵ Ωcm, and has electrons driven by electron beam irradiation for forming a resist pattern for etching the light semitransmissive film 2a.
Also, it was possible to sufficiently prevent static electricity from being charged.

The light semi-transmissive film of this embodiment can be etched by using a reactive dry etching (RIE) parallel plate type dry etching apparatus under the following conditions. The etching selection ratio with respect to the transparent substrate 1 was 17, and the light semi-transmissive film 2a could be etched without damaging the transparent substrate 1.

Etching gas: Cl ₂ RF power: 700 W Gas pressure: 1.5 Pa Electrode temperature: 0 ° C. Further, the light semi-transmissive film 2a (light semi-transmissive portion 2) of this embodiment is
Since the adhesiveness to the transparent substrate 1 is sufficient, it can withstand the ultrasonic cleaning performed in the normal photomask cleaning step, and since it has excellent acid resistance, it is performed in the normal photomask cleaning step. It was able to withstand washing with sulfuric acid.

Further, the light semi-transmissive portion 2 of this example contained volatile fluorine, but had sufficient thermal stability that it did not change even by heat treatment at 400 ° C.

Further, when the phase shift mask was used, the depth of focus equivalent to that of the conventional phase shift mask was obtained.

(Embodiment 6) In the halftone type phase shift mask blank and the halftone type phase shift mask of Example 6, the light semi-transmissive portion 2 and the light semi-transmissive film 2a in Example 1 were changed as follows. It is a thing.

In Example 6, the light semi-transmissive portion 2 and the light semi-transmissive film 2a were made of silicon carbide Six C, and the light transmissive film was formed by the following steps.

SiH ₄ 50 sccm and CH ₄ 30 sccc
A light semi-transmissive film 2a made of Six C (X is about 1.7) formed by using a plasma CVD apparatus with m as a gas source.
(Refractive index 2.6, film thickness 775 angstrom) was obtained.
The light transmittance of the light semi-transmissive portion 2a at the wavelength λ = 248 nm was 8%.

The predetermined light transmittance and conductivity of the light semi-transmissive portion 2 can be selected by selecting the mixture ratio of Si and C. In this case, if the content of C is increased, the light transmittance is increased, but the conductivity is decreased.

According to the sixth embodiment described above, the light semi-transmissive film 2a is formed.
Has a sheet resistance of 9.2 × 10 ⁶ Ω, and is sufficiently charged with electrons and static electricity driven by electron beam irradiation for forming a resist pattern for etching the light semi-transmissive film 2a. It was something that could be prevented.

The light semi-transmissive film 2a of this embodiment can be etched by using a reactive dry etching (RIE) parallel plate type dry etching apparatus under the following conditions. Transparent substrate 1
The etching selection ratio with respect to was 17 and the light semi-transmissive film 2a could be etched without damaging the transparent substrate 1.

Etching gas: SiCl4 + N2 RF power: 1000 W Gas pressure: 3.5 Pa Electrode temperature: 20 ° C. Further, the light semi-transmissive film 2a (light semi-transmissive portion 2) of this embodiment is
Since the adhesive force with the transparent substrate 1 is sufficient, it can withstand the ultrasonic cleaning performed in the normal photomask cleaning step, and since it has excellent acid resistance, it can be used in the normal photomask cleaning step. It was able to withstand the so-called sulfuric acid cleaning.

Also in this example, as in Example 6, sufficient thermal stability was obtained.

When the phase shift mask was used, the depth of focus equivalent to that of the conventional phase shift mask was obtained.

Furthermore, since the light transmissivity of the light semi-transmissive film 2a for visible light is 50 to 60%, it is possible to perform alignment sufficiently.

(Example 7) In the halftone type phase shift mask blank and the halftone type phase shift mask of Example 7, the light semi-transmissive portion 2 and the light semi-transmissive film 2a in Example 1 were changed as follows. It is a thing.

In the seventh embodiment, the light semi-transmissive portion 2 and the light semi-transmissive film 2a are made of silicon carbide (Six C). In this embodiment, a KrF excimer laser (wavelength λ = 248 nm) is used as the exposure light, and the light semi-transmissive portion 2 has a predetermined phase shift amount, a predetermined light shielding performance, and a predetermined conductivity performance with respect to this exposure light. In order to obtain simultaneously, silicon carbide is added to Si _1.8 C _1.1 (refractive index 2.
7), the film thickness was set to 729 Å, and the light transmittance for the wavelength λ = 248 nm was set to 7%.

The light semi-transmissive film 2a can be formed by sputtering using Si _1.5 C _1.7 as a target.

The predetermined light transmittance and conductive performance of the light semi-transmissive portion 2 can be selected by selecting the mixing ratio of Si and C. In this case, if the content of C is increased, the light transmittance is increased, but the conductivity is decreased.

According to the seventh embodiment described above, the light semi-transmissive film 2a is formed.
Has a sheet resistance of 6.8 × 10 ⁶ Ω, and is sufficiently charged with electrons and static electricity driven by electron beam irradiation for forming a resist pattern for etching the light semitransmissive film 2a. It was something that could be prevented.

Further, the etching of the light semi-transmissive film of this embodiment can be carried out under the following conditions by using a reactive dry etching (RIE) parallel plate type dry etching apparatus. The etching selection ratio to the transparent substrate 1 was 10, and the light semitransmissive film 2a could be etched without damaging the transparent substrate 1.

Etching gas: SiCl ₄ + N ₂ RF power: 1000 W Gas pressure: 3.5 Pa Electrode temperature: 20 ° C. Further, the light semi-transmissive film 2a (light semi-transmissive portion 2) of this embodiment is
Since the adhesive force with the transparent substrate 1 is sufficient, it can withstand the ultrasonic cleaning performed in the normal photomask cleaning step, and since it has excellent acid resistance, it can be used in the normal photomask cleaning step. It was able to withstand the so-called sulfuric acid cleaning.

Further, when the phase shift mask was used, the depth of focus equivalent to that of the conventional phase shift mask was obtained.

Furthermore, since the light transmissivity of the light semi-transmissive film 2a for visible light is 50 to 60%, it is possible to perform alignment sufficiently.

FIG. 5 shows another example (example in which X is changed) in which the light semi-transmissive portion 2 and the light semi-transmissive film 2a are made of silicon carbide (Six C). According to this, X is 0.8
If it is below, the conductivity becomes poor (more than 5 × 10 ⁷ ), and if X is 10 or more, the light transmittance becomes too small (the light transmittance deviates from 4 to 20%). Therefore, it is necessary to set 0.8 ≦ X ≦ 10.

(Example 8) In the halftone type phase shift mask blank and the halftone type phase shift mask of Example 8, the light semi-transmissive portion 2 and the light semi-transmissive film 2a in Example 1 were changed as follows. It is a thing.

In Example 8, the light semi-transmissive portion 2 and the light semi-transmissive film 2a are made of chromium containing oxygen. In this embodiment, i-line (wavelength λ = 365 nm) is used as the exposure light, and the light semi-transmissive portion 2 provides a predetermined phase shift amount, a predetermined light blocking performance, and a predetermined conductive performance with respect to this exposure light. In order to obtain them at the same time, the atomic ratio of Cr / O was set to 0.92 (refractive index 2.36) and the film thickness was set to 1342 angstroms, and the light transmittance for the wavelength λ = 365 nm was set to 4.2%.

The light-semitransmissive film 2a can be formed by DC sputtering in an Ar gas atmosphere using a mixed target (density 90%) of 47 wt% chromium + 53 wt% chromium oxide (Cr ₂ O ₃ ).

The predetermined light transmittance and conductivity of the light semi-transmissive portion 2 can be selected by selecting the atomic ratio of Cr and O. In this case, increasing the O content increases the light transmittance but decreases the conductivity.

According to the above eighth embodiment, the light semi-transmissive film 2a is formed.
Has a sheet resistance of 7.8 × 10 ⁴ Ω and is sufficiently charged with electrons and static electricity driven by electron beam irradiation for forming a resist pattern for etching the light semi-transmissive film 2a. It was something that could be prevented.

Further, the light semi-transmissive film of the present embodiment can be etched by a wet etching method using cerium secondary ammonium nitrate, and the etching selection ratio with the transparent substrate 1 at that time is almost infinite. The light semi-transmissive film 2a can be etched without damaging the transparent substrate 1.

In this embodiment, the atomic ratio of chromium and oxygen (Cr / O) needs to be 0.3 or more. Cr / O
This is because if the value is less than 0.3, the predetermined conductivity cannot be obtained. FIG. 6 is a table collectively showing each of the above embodiments.

The present invention is not limited to the above embodiment.

In Examples 1 and 2, the light-semitransmissive film 2a contained SnOx and Sb and InO ₂ , respectively. In addition to these, Sb, Nb, Bi and T were included.
It may be an oxide of a, W or Mo. The degree of oxidation of SnOx can be appropriately determined according to the types of the other components contained above.

In Examples 4 and 5, the light-semitransmissive films 2a are amorphous Si: F: H and amorphous S, respectively.
i: F contains phosphorus and boron, but instead of phosphorus and boron, an element capable of having a trivalent or pentavalent charge, that is, arsenic (As), gallium (Ga), antimony (S).
It may be a 3B group or 5B group element such as b), or a transition metal having a trivalent or pentavalent charge. The light transmittance can be controlled by including at least one of fluorine and hydrogen.

In Examples 6 and 7, Si of the light semi-transmissive film 2a was used.
It is preferable that X of x C is 0.8 ≦ X ≦ 10. The reason is that if X is smaller than 0.8, the sheet resistance is too large to prevent charging, and if X is larger than 10, the transmittance is too small.

[0104]

As described above in detail, the halftone type phase shift mask blank and the halftone type phase shift mask according to the present invention have a single layer of light for forming a light transmitting portion on a transparent substrate. At the same time as having a semi-transmissive film, the light semi-transmissive film has the property of transmitting light of an intensity that does not substantially contribute to exposure and the property of shifting the phase of the exposure light by a predetermined amount, and at the Since it also has a conductivity higher than the level at which electric charges are not charged, it is possible to prevent charge accumulation and static electricity charging during electron beam writing with a simple film structure.

[Brief description of drawings]

1A and 1B are diagrams showing a halftone type phase shift mask blank and a halftone type phase shift mask according to Example 1, and FIG. 1A is a sectional view showing the halftone type phase shift mask blank; b) is a cross-sectional view showing a halftone type phase shift mask.

FIG. 2 is an explanatory diagram of a manufacturing process of the halftone phase shift mask according to the first embodiment.

FIG. 3 is an explanatory diagram of the operation of a halftone type phase shift mask.

FIG. 4 is a graph showing the dependence of the light transmittance on the wavelength of the light semi-transmissive film of the halftone phase shift mask blank according to Example 1.

FIG. 5 is a table showing another example (example in which X is changed) in which the light semi-transmissive portion 2 and the light semi-transmissive film 2a are made of silicon carbide (Six C).

FIG. 6 is a table showing a summary of each example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Transparent substrate, 2 ... Light semi-transmission part, 2a ... Light semi-transmission film, 3
... light transmitting portion, 4 ... resist pattern, 4a ... resist film.

Claims (9)

[Claims] 1. A mask for performing fine pattern exposure, wherein a mask pattern formed on the surface of a transparent substrate is substantially exposed with a light transmitting portion that transmits light having an intensity that substantially contributes to the exposure. And a light semi-transmissive portion that transmits light of an intensity that does not contribute to, and by making the phase of light passing through this light semi-transmissive portion and the phase of light passing through the light transmissive portion different, Used as a material in the manufacture of a halftone phase shift mask that allows the light passing through the vicinity of the boundary between the light transmitting portion and the light semi-transmitting portion to cancel each other out and maintain good contrast at the boundary portion. The halftone phase shift mask blank has a single-layer light-semitransmissive film for forming the light-transmissive portion on a transparent substrate, and the light-semitransmissive film has a strength that does not substantially contribute to exposure. A half which has a property of transmitting light and a property of shifting the phase of exposure light by a predetermined amount, and at the same time has a conductivity higher than a degree that electric charges are not charged during electron beam drawing. Tone type phase shift mask blank. 2. The halftone phase shift mask blank according to claim 1, wherein the sheet resistance, which is a sheet resistance of 1 cm ² of the light semitransparent film, is 5 × 10 ⁷ Ω or less. Halftone phase shift mask blank. 3. The halftone type phase shift mask blank according to claim 1, wherein the light semitransmissive film has a transmittance of 4 to 20% with respect to exposure light. Mask blank. 4. The halftone phase shift mask blank according to claim 1, wherein the light semitransmissive film is made of a material containing SnOx. . 5. The halftone phase shift mask blank according to claim 1, wherein the light-semitransmissive film contains at least one element capable of having trivalent or pentavalent charges. A halftone type phase shift mask blank, which is a film. 6. The halftone phase shift mask blank according to claim 1, wherein the light semitransmissive film is made of silicon carbide (Six C). Mask blank. 7. The halftone phase shift mask blank according to claim 6, wherein the value of X of the silicon carbide (Six C) is 0.8 ≦ X.
A halftone type phase shift mask blank, wherein ≦ 10. 8. The halftone phase shift mask blank according to claim 1, wherein the light-semitransmissive film contains chromium and oxygen, and the atomic ratio of chromium and oxygen (Cr / O). ) Is 0.3 or more, a halftone type phase shift mask blank characterized by comprising a material. 9. A mask for performing fine pattern exposure, wherein a mask pattern formed on the surface of a transparent substrate is substantially exposed with a light transmitting portion that transmits light having an intensity that substantially contributes to the exposure. And a light semi-transmissive portion that transmits light of an intensity that does not contribute to, and by making the phase of light passing through this light semi-transmissive portion and the phase of light passing through the light transmissive portion different, 9. A halftone phase shift mask, wherein the light passing through the vicinity of the boundary between the light transmitting portion and the light semi-transmitting portion cancels each other so that the contrast of the boundary can be maintained well. By subjecting the light-semitransmissive film of the phase shift mask blank according to any one to a patterning process of partially removing the light-semitransmissive film according to a predetermined pattern, Halftone phase shift mask, characterized in that a pattern was formed.