JP4578960B2 - Halftone phase shift mask blank and method of manufacturing halftone phase shift mask - Google Patents

Description

  The present invention relates to a phase shift mask that can improve the resolution of a transfer pattern by providing a phase difference between exposure light that passes through the mask, and more particularly, to a halftone phase shift mask and a halftone that is a master plate thereof. The present invention relates to a mold phase shift mask blank.

In semiconductor LSI manufacturing or the like, a photomask is used as a mask for fine pattern exposure. As a kind of this photomask, a phase shift mask that can improve the resolution of a transfer pattern by giving a phase difference between exposure light passing through the mask is used.
In recent years, a phase shift mask called a halftone phase shift mask has been developed as one of the phase shift masks. In this halftone phase shift mask, the mask pattern formed on the transparent substrate is substantially exposed to a portion that transmits light having an intensity that contributes substantially to exposure (hereinafter referred to as a light transmitting portion). And a portion that transmits light having an intensity that does not contribute to light (hereinafter referred to as a light semi-transmissive portion), and the phase of light passing through the light semi-transmissive portion is shifted to transmit the light semi-transmissive portion. The light transmitted through the vicinity of the boundary between the light transmission part and the light semi-transmission part can be obtained by making the phase of the transmitted light substantially invert with respect to the phase of the light transmitted through the light transmission part. By contrasting each other, the contrast of the boundary portion can be maintained satisfactorily.

  In such a halftone phase shift mask, the light semi-transmission part has both a light shielding function for substantially blocking exposure light and a phase shift function for shifting the phase of light, There is no need to separately form a phase shift film pattern with high transmittance that mainly controls the phase angle and a light shielding film pattern with low transmittance that mainly controls the light translucency, and the configuration is simple and easy to manufacture. It has the characteristic of being.

  In Patent Document 1 below, a light semi-transmissive film containing nitrogen, metal, and silicon as main components is transparent so that a light semi-transmissive part having a predetermined phase angle and transmittance and excellent film characteristics can be obtained. A halftone phase shift mask blank formed on a substrate and heat-treating the light semi-transmissive film is described. The light translucent film described in Patent Document 1 shows that the surface layer contains approximately 40 atomic% of oxygen by ESCA analysis results.

JP 2002-162726 A

In recent years, with the miniaturization of circuit patterns, the exposure wavelength has been shortened, and the exposure wavelength is changing from 248 nm (KrF excimer laser) to 193 nm (ArF excimer laser). Since the ArF excimer laser has a short wavelength, the energy of the laser light increases. For this reason, the chemical reaction on the mask surface is promoted by the laser irradiation, whereby the formation of some precipitates is promoted, and there is a problem that the precipitates are generated and adhered as foreign matters on the mask. One such deposit has been identified as ammonium sulfate.
The mask is generally cleaned using a sulfuric acid-based cleaning agent in the final process. It is thought that sulfuric acid or sulfate ions derived from the sulfuric acid-based cleaning agent used in the cleaning process often remain in the cleaned mask. For this reason, it is considered that the reaction of ammonium ions generated for some reason with this sulfate ion is promoted by laser irradiation, which is the cause of precipitates.

The source of ammonium ions is considered to be substances or deposits derived from the atmosphere or pellicle. However, according to the study of the present inventor, as a result of investigating the use of a material containing nitrogen in the thin film used for the mask as described above, the thin film containing nitrogen is less than the thin film not containing nitrogen. It was found that many ammonium ions were present on the membrane surface. Therefore, it is considered that the thin film containing nitrogen may promote the precipitation of ammonium sulfate that can be a foreign matter defect.
Further, with respect to chemical resistance (acid resistance, alkali resistance) to the cleaning liquid, the demand has become more severe as the wavelength of the exposure light source becomes shorter.
Under such circumstances, the light translucent film as described in Patent Document 1 has not necessarily been sufficient in the above-described production suppression of ammonium ions and chemical resistance.

  The present invention has been made in view of the above-described problems, and uses a halftone phase shift mask blank that suppresses generation of ammonium ions and has excellent chemical resistance, and the halftone phase shift mask blank. An object of the present invention is to provide a halftone phase shift mask obtained by the above method.

In order to solve the above problems, the present invention has the following configuration.
(Configuration 1) A halftone phase shift mask blank in which a light translucent film having a predetermined transmittance with respect to an exposure wavelength and having nitrogen, metal and silicon as main components is formed on a transparent substrate. The halftone phase shift mask blank is characterized in that the oxygen content in the surface layer of the light translucent film is 35 atomic% or more and the metal content is 5 atomic% or less.
Like composition 1, it has a predetermined transmittance with respect to the exposure wavelength, and the oxygen content in the surface layer of the light semi-transmissive film whose main components are nitrogen, metal and silicon is 35 atomic% or more, and metal The content of was made 5 atomic% or less. Thereby, it is excellent in the effect of suppressing the generation of ammonium ions, can prevent the occurrence of foreign matter defects caused by ammonium ions even when the exposure wavelength is as short as 200 nm or less, and has excellent chemical resistance and a light semi-transmissive film Thus, a halftone phase shift mask blank that does not cause a change in optical characteristics is obtained.

(Structure 2) The halftone phase shift mask blank according to Structure 1, wherein the content of nitrogen in the surface layer of the light translucent film is 45 atomic% or less.
When the nitrogen content in the surface layer of the light-semitransmissive film is 45 atomic% or less, both the above-described effects of suppressing ammonium ion generation and chemical resistance can be further improved.
(Structure 3) The halftone phase shift mask blank according to Structure 1 or 2, wherein the surface layer has a thickness of 1 nm to 5 nm.
By setting the film thickness of the surface layer of the light semi-transmissive film to 1 nm or more and 5 nm or less, both the above-described ammonium ion generation suppressing effect and chemical resistance can be remarkably obtained, and in the exposure wavelength region of 200 nm or less. The optical properties (transmittance, phase angle) are not affected.

(Structure 4) The halftone phase shift mask blank according to any one of Structures 1 to 3, wherein the light semitransmissive film excluding the surface layer does not substantially contain oxygen.
Since the light semi-transmissive film excluding the surface layer does not substantially contain oxygen, the chemical resistance is good and the optical characteristics of the light semi-transmissive film do not change.
(Structure 5) The halftone phase shift mask blank according to any one of Structures 1 to 4, wherein the exposure wavelength is 200 nm or less.
The present invention is particularly effective because it has an excellent effect of suppressing the production of ammonium ions, can prevent foreign matter defects caused by ammonium ions even when the exposure wavelength is as short as 200 nm, and is excellent in chemical resistance. is there.

(Structure 6) Light having main components of nitrogen, metal, and silicon on a transparent substrate by patterning the light semitransmissive film of the halftone phase shift mask blank according to any one of Structures 1 to 5. A halftone phase shift mask manufacturing method is characterized in that a semi-transmissive portion is formed.
By patterning the light-semitransmissive film of the halftone phase shift mask blank according to any one of Structures 1 to 5, ammonium is formed by forming a light-semitransmissive part mainly composed of nitrogen, metal, and silicon. A halftone phase shift mask that suppresses the generation of ions, can prevent generation of foreign matter defects caused by ammonium ions even when the exposure wavelength is as short as 200 nm or less, and has excellent chemical resistance can be obtained. .

  According to the present invention, generation of ammonium ions can be suppressed, generation of foreign matter defects caused by ammonium ions can be prevented even when the exposure wavelength is as short as 200 nm or less, and chemical resistance is excellent. A halftone phase shift mask blank in which the optical characteristic change of the light semi-transmissive film does not occur is obtained. In addition, by using this halftone phase shift mask blank, it is possible to prevent the occurrence of foreign matter defects caused by ammonium ions even when the exposure wavelength is as short as 200 nm or less, and excellent in chemical resistance. A halftone phase shift mask is obtained.

Hereinafter, the present invention will be described in detail by embodiments.
1A is a cross-sectional view showing an embodiment of a halftone phase shift mask blank of the present invention, and FIG. 1B shows an embodiment of the halftone phase shift mask of the present invention. It is sectional drawing.
As shown in FIG. 1A, an embodiment of the halftone phase shift mask blank of the present invention is a halftone phase shift mask blank 10 in which a light semitransmissive film 2 is formed on a transparent substrate 1. It is. This light semi-transmissive film 2 has a predetermined transmittance with respect to the exposure wavelength and is made of a material mainly composed of nitrogen, metal, and silicon, and the oxygen content in the surface layer of the light semi-transmissive film is 35 atomic%. The metal content is 5 atomic% or less.
As described above, the oxygen content in the surface layer of the light semi-transmissive film having a predetermined transmittance with respect to the exposure wavelength and containing nitrogen, metal, and silicon as main components is 35 atomic% or more, and the metal content. Is 5 atomic% or less, it is excellent in the effect of suppressing the formation of ammonium ions, can prevent the occurrence of foreign matter defects due to ammonium ions even when the exposure wavelength is as short as 200 nm or less, and is resistant to chemicals. A halftone phase shift mask blank which is excellent in properties and does not cause changes in the optical characteristics of the light semi-transmissive film can be obtained.

  Conventionally, a large amount of ammonium ions are present on the film surface due to the components of the light-semitransmissive film. In particular, when the wavelength of the exposure light source is a short wavelength of 200 nm or less, this ammonium ion and the mask surface after cleaning The reaction with sulfuric acid or sulfate ions derived from the sulfuric acid-based detergent remaining in the catalyst is promoted to precipitate ammonium sulfate that can be a foreign matter defect. Furthermore, the chemical resistance of the light semi-transmissive film is not always sufficient, and therefore there is a problem that the optical characteristics of the light semi-transmissive film change due to the chemical resistance. As a result of intensive studies, the present inventor has found that excellent effects can be obtained by adjusting the state (composition) of the surface layer of the light-semitransmissive film in terms of the suppression effect of ammonium ion generation and chemical resistance.

That is, the oxygen content in the surface layer of the light translucent film is set to 35 atomic% or more. If the oxygen content in the surface layer of the light semi-transmissive film is less than 35 atomic%, an effect of suppressing ammonium ion generation cannot be obtained, which is not preferable. Further, the metal content in the surface layer of the light translucent film is set to 5 atomic% or less. If the metal content in the surface layer of the light semi-transmissive film exceeds 5 atomic%, the chemical resistance (acid resistance and alkali resistance) deteriorates, which is not preferable.
In the present invention, the oxygen content in the surface layer of the light translucent film is more preferably 40 atomic% or more, and the metal content is more preferably 3 atomic% or less.

In addition, the light semi-transmissive film in the present invention is a film containing metal, silicon and nitrogen as main components. However, in addition to metal and silicon, the light semi-transmissive film contains nitrogen, so that the optical characteristics (transmittance) of the light semi-transmissive film are included. , Phase angle) can be controlled.
In order to further improve both the above-described effects of suppressing the formation of ammonium ions and chemical resistance (acid resistance and alkali resistance), the nitrogen content in the surface layer of the light translucent film should be 45 atomic% or less. preferable. In the present invention, the nitrogen content in the surface layer of the light translucent film is more preferably 40 atomic% or less, and still more preferably 35 atomic% or less.

  Moreover, it is preferable that the film thickness of the surface layer necessary for obtaining both the above light resistance and chemical resistance characteristics is 1 nm or more and 5 nm or less. When the film thickness of the surface layer is less than 1 nm, both the above-described effects of suppressing the formation of ammonium ions and the chemical effects are not remarkably exhibited, which is not preferable. Moreover, when the film thickness of the surface layer exceeds 5 nm, it is not preferable because optical characteristics (transmittance, phase angle) in an exposure wavelength region of 200 nm or less are affected. In the present invention, the film thickness of the surface layer is more preferably 1 nm or more and 3 nm or less.

Moreover, it is preferable that oxygen is not contained substantially in the light semipermeable film except a surface layer. This is because if the light semi-transmissive film excluding the surface layer contains oxygen, the chemical resistance is deteriorated, and the optical characteristics of the light semi-transmissive film are affected. Here, “substantially free of oxygen” means that oxygen is not contained at all, or even if oxygen is contained, its content is 3 atomic% or less.
In order to obtain a light semi-transmissive film in which the oxygen content in the surface layer of the light semi-transmissive film is 35 atomic% or more and the light semi-transmissive film excluding the surface layer is substantially free of oxygen, for example, A method of forming a film by supplying an oxygen gas in a film forming atmosphere gas immediately before completion of film formation of the light semi-transmissive film, a method of performing heat treatment in the atmosphere after forming the light semi-transmissive film on the substrate, etc. are preferable. Can be mentioned. In this case, the oxygen gas flow rate, the processing conditions such as the temperature and time for the heat treatment, and the like may be set appropriately in consideration of the oxygen content in the surface layer.

  Preferred examples of the metal that is a constituent element of the light translucent film include metals such as molybdenum (Mo), tantalum (Ta), tungsten (W), titanium (Ti), and chromium (Cr). These materials containing metal and silicon have a relatively high refractive index with respect to exposure light having a wavelength of 200 nm or less, and can reduce the film thickness for shifting (preferably reversing) the phase. This is because the light transmittance (light shielding performance) with respect to the exposure light can also be set to a good value.

  In consideration of optical characteristics (transmittance, phase angle) in an exposure wavelength region of 200 nm or less, the composition of the light translucent film excluding the surface layer is 2 to 8 atomic% for metal, 20 to 50 atomic% for silicon, Nitrogen is preferably 30 to 70 atomic%.

  Examples of the material of the light translucent film mainly composed of nitrogen, metal, and silicon include nitrided molybdenum and silicon (MoSiN-based material), nitrided tantalum and silicon (TaSiN-based material), and nitrided tungsten. And silicon (WSiN-based material), nitrided titanium and silicon (TiSiN-based material), nitrided chromium and silicon (CrSiN-based material), and the like. Among these materials, a material made of nitrided molybdenum and silicon (MoSiN material) whose metal is molybdenum (Mo) or tantalum (Ta), a material made of nitrided tantalum and silicon (TaSiN material), This is preferable in terms of processing characteristics (pattern controllability) in the mask manufacturing process and prevention of defects due to a sputter target factor.

Such a light semi-transmissive film can be formed by, for example, sputtering film formation (DC sputtering, RF sputtering, ion beam sputtering, etc.) in a low-pressure atmosphere. By using a low-pressure atmosphere, a dense film is easily formed, which is preferable for improving chemical resistance.
The light semi-transmissive film has two functions of a light shielding function for substantially blocking exposure light and a phase shift function for shifting the phase of light. Since the values of these functions differ depending on the exposure light source and its wavelength when the mask is used, it is necessary to design and select the values corresponding to the exposure light source to be used and its wavelength.

The phase shift amount of the light semi-transmissive film can be controlled by adjusting the film composition and film thickness of the light semi-transmissive film. When the phase shift amount is φ, the wavelength of the exposure light is λ, and the refractive index of the light semi-transmissive film is n, the film thickness d of the light semi-transmissive film can be determined by the following equation (1).
d = (φ / 360) × [λ / (n−1)] (1)
The phase shift amount φ in the equation (1) is most desirably 180 degrees from the viewpoint of improving the resolution, but may be practically about 160 degrees to 200 degrees.

  The light transmittance (light shielding performance) of the light semi-transmissive film with respect to the exposure light is generally about 2 to 20%, although it depends on the sensitivity of the resist used for forming a pattern of a semiconductor element or the like. Within this range, the higher the light transmittance, the higher the phase effect, and thus the higher the light transmittance. However, in the case of a line and space pattern, it is preferable that the light transmittance is low, and in the case of a hole or dot pattern, it is preferable that the light transmittance is high. The light transmittance of the light semi-transmissive film can be controlled by adjusting the film composition.

  In the above embodiment, the case where the light semi-transmissive film is a single layer is shown. However, a light semi-transmissive film having a multilayer structure in which two or more light semi-transmissive films having a single layer structure are stacked may be used. . In this case, it is preferable that the oxygen content in the surface layer of the upper light-semitransmissive film located at the farthest position from the substrate is 35 atomic% or more and the metal content is 5 atomic% or less.

  The transparent substrate used in the halftone phase shift mask blank of the present invention is not particularly limited as long as it is a substrate transparent to the exposure wavelength to be used. Examples of the transparent substrate include a quartz substrate and other various glass substrates (for example, soda lime glass and aluminosilicate glass). In particular, a quartz substrate is suitable because it is highly transparent to, for example, ArF excimer laser (wavelength 193 nm) or exposure light having a shorter wavelength.

  The halftone phase shift mask blank of the present invention is manufactured by forming a light semi-transmissive film on a transparent substrate such as a quartz substrate using a known thin film forming method. In order to prevent generation of particles due to film peeling of the light semi-transmissive film at the peripheral edge of the substrate, a light semi-transmissive film may be formed in a region excluding the peripheral edge on the main surface of the transparent substrate.

FIG. 1B shows a light semi-transmissive portion 2a having nitrogen, metal and silicon as main components on the transparent substrate 1 by patterning the light semi-transmissive film 2 of the halftone phase shift mask blank 10 described above. The halftone phase shift mask 20 in which the light transmission part 3 was formed is shown.
FIG. 2 shows an example of a manufacturing process of a halftone phase shift mask using the halftone phase shift mask blank of the present invention.
According to this, first, a resist film 4 (for example, a positive resist film for electron beams) is formed on the light semi-transmissive film 2 of the halftone phase shift mask blank 10 (see FIGS. 1A and 1B). . Next, a predetermined pattern is drawn on the resist film 4 using an electron beam drawing machine, and development processing is performed to form a resist pattern 4a (see FIG. 5C).

Next, using the resist pattern 4a as a mask, the light semi-transmissive film 2 is etched to form a light semi-transmissive film pattern (light semi-transmissive portion 2a) (see FIG. 4D). Then, the remaining resist pattern 4a is removed by oxygen ashing or the like.
As described above, the halftone phase shift mask 20 in which the light semi-transmissive portion 2a and the light transmissive portion 3 formed of a patterned light semi-transmissive film are formed on the transparent substrate 1 can be obtained (see FIG. (See (e)).

  As described above, the halftone phase shift mask blank and the halftone phase shift mask of the present invention have an exposure wavelength of 200 nm or less, for example, ArF excimer laser (wavelength 193 nm) or shorter exposure light. It is suitable for the case. In other words, the present invention is particularly effective in suppressing the production of ammonium ions, and even when the exposure wavelength is as short as 200 nm or less, it is possible to prevent the occurrence of foreign matter defects caused by ammonium ions, and the chemical resistance is excellent. It is valid.

Hereinafter, the present invention will be described more specifically with reference to examples.
Example 1
Using a mixed target of molybdenum (Mo) and silicon (Si) (Mo: Si = 10 mol%: 90 mol%), a mixed gas atmosphere of argon (Ar), nitrogen (N ₂ ), and helium (He) (Ar: _{N 2: He = 10sccm: 80sccm} : 60sccm, pressure 0.2 Pa), by reactive sputtering (DC sputtering), a synthetic quartz glass substrate, the light semi-transmitting film (film of molybdenum and silicon is nitrided (MoSiN) (Thickness: 69 nm).
Subsequently, after heat-treating at 420 ° C. for 15 minutes in the air, the surface of the light translucent film was scrubbed with pure water to produce a halftone phase shift mask blank for ArF excimer laser exposure.

The obtained halftone phase shift mask blank had an transmittance of 6.0% and a phase angle of 180 ° in an ArF excimer laser (wavelength: 193 nm).
In addition, the obtained semi-transmissive film was subjected to composition analysis in the depth direction by Auger electron spectroscopy (AES). The composition of the light translucent film excluding the surface layer (about 3 nm) is uniform in the film thickness direction, 4.2 atomic% of molybdenum (Mo), 35.8 atomic% of silicon (Si), and 60 of nitrogen (N). 0.0 atomic% and oxygen (O) were 0 atomic%. The composition of the surface layer (about 3 nm) of the light-semitransmissive film is as follows: molybdenum (Mo) is 1.9 atomic%, silicon (Si) is 18.7 atomic%, nitrogen (N) is 33.5 atomic%, oxygen (O) was 45.9 atomic%.

Next, the chemical resistance of the light translucent film was examined. The acid resistance of the light semi-transmissive film was evaluated by a change in phase angle before and after being immersed in hot concentrated sulfuric acid (96% H ₂ SO ₄ , temperature: 100 ° C.) for 120 minutes. Negative values indicate that the phase angle has decreased. Further, the alkali resistance of the light semi-transmissive film is 120 minutes in ammonia perwater (29% NH ₃ : 30% H ₂ O ₂ : H ₂ O = 1: 2: 1 (volume ratio), temperature: 25 ° C.). The phase angle change before and after immersion was evaluated. As before, a negative value indicates that the phase angle has decreased. As a result, good results were obtained with an acid resistance of -0.3 [deg.] And an alkali resistance of -1.5 [deg.] In the light semi-transmissive film in this example. In addition, the phase angle was measured using the phase difference measuring machine (Lasertec company make: MPM-193).
Also, when the ammonium ion _(NH 4 +) concentration of the light semi-transmitting film surface was measured by an ion chromatographic method with pure water extraction was 2.5 ng / cm ^2.

Next, using this halftone phase shift mask blank, a halftone phase shift mask was produced by the following method.
That is, after applying and forming a positive resist film for electron beam drawing on the light semi-transmissive film of the halftone phase shift mask blank, a predetermined pattern is drawn by an electron beam drawing machine, and development processing is performed to form a resist pattern. Formed.
Next, by using this resist pattern as a mask, the exposed portion of the light semi-transmissive film made of nitrided molybdenum and silicon is removed by dry etching with a mixed gas of SF ₆ gas and He gas, and the pattern of the light semi-transmissive film is obtained. (Holes, dots, etc.) were obtained.
Next, after removing the remaining resist pattern, it is immersed in 98% sulfuric acid (H ₂ SO ₄ ) at 100 ° C. for 15 minutes, washed with sulfuric acid, rinsed with pure water or the like, and used for ArF excimer laser exposure. A halftone phase shift mask was obtained.

  This halftone phase shift mask has few ammonium ions on the surface of the semi-transparent film. Therefore, when pattern transfer is performed by laser irradiation with a short wavelength, such as an ArF excimer laser, foreign matter defects due to ammonium sulfate. Can be prevented.

Hereinafter, a comparative example with respect to the above embodiment will be described.
(Comparative Example 1)
A halftone phase shift mask for ArF excimer laser exposure in the same manner as in Example 1, except that after the light semitransmissive film was formed, heat treatment was performed in a nitrogen atmosphere at 200 ° C. for 15 minutes. A blank was produced.
The obtained halftone phase shift mask blank had an transmittance of 6.0% and a phase angle of 180 ° in an ArF excimer laser (wavelength: 193 nm).

Further, as a result of the composition analysis in the depth direction of the obtained light semi-transmissive film by Auger electron spectroscopy (AES), the composition of the light semi-transmissive film excluding the surface layer (about 3 nm) is uniform in the film thickness direction. Thus, the composition was the same as in Example 1. Further, the surface layer (about 3 nm) of the light translucent film has molybdenum (Mo) of 2.1 atomic%, silicon (Si) of 21.2 atomic%, nitrogen (N) of 42.4 atomic%, oxygen ( It was found that 3) atomic percent of O) was included.
Next, the chemical resistance of the light translucent film was examined in the same manner as in Example 1. As a result, the acid resistance was −0.6 ° and the alkali resistance was −3.0 °, which was slightly worse than that of Example 1.
Further, the ammonium ion (NH 4 ₊₎ concentration of the light semi-transmitting film surface was measured by ion chromatography with pure water extraction has resulted bad and 75 ng / cm ^2.

  Next, a halftone phase shift mask was produced in the same manner as in Example 1 using this halftone phase shift mask blank. Since this halftone phase shift mask has a large amount of ammonium ions on the surface of the translucent film, when pattern transfer is performed by laser irradiation with a short wavelength such as an ArF excimer laser, foreign matter defects due to ammonium sulfate are eliminated. Generation cannot be prevented.

(Comparative Example 2)
In Example 1 described above, the composition of the mixed target of molybdenum (Mo) and silicon (Si) is Mo: Si = 12 mol%: 88 mol%, and the atmosphere gas is a mixture of argon (Ar) and nitrogen (N ₂ ). A gas translucent film (film thickness: 69 nm) of nitrided molybdenum and silicon (MoSiN) is formed on a synthetic quartz glass substrate by reactive sputtering (DC sputtering) by changing to gas and adjusting the flow rate and pressure. Then, a halftone phase shift mask blank for ArF excimer laser exposure was produced in the same manner as in Example 1 except that heat treatment was performed under the same conditions as in Comparative Example 1 described above.
The obtained halftone phase shift mask blank had an transmittance of 6.0% and a phase angle of 180 ° in an ArF excimer laser (wavelength: 193 nm).

In addition, as a result of analyzing the composition in the depth direction by Auger electron spectroscopy (AES), the surface layer (about 3 nm) of the light semi-transmissive film was found to have molybdenum (Mo) of 5. It was found that 7 atom%, silicon (Si) 45.6 atom%, nitrogen (N) 30.1 atom%, and oxygen (O) 18.6 atom% were contained.
Next, as a result of investigating the chemical resistance of the light semi-transmissive film in the same manner as in Example 1, the acid resistance was -1.5 °, and the alkali resistance was -4.2 °, which is much higher than that of Example 1. It was bad.
In addition, when the ammonium ion (NH ₄ +) concentration on the surface of the light semi-transmissive film was measured by an ion chromatography method using pure water extraction, 105 ng / cm ² , which was a worse result than Comparative Example 1.

  Using this halftone phase shift mask blank, a halftone phase shift mask was produced in the same manner as in Example 1. Since this halftone phase shift mask has a large amount of ammonium ions on the surface of the translucent film, when pattern transfer is performed by laser irradiation with a short wavelength such as an ArF excimer laser, foreign matter defects due to ammonium sulfate are eliminated. Generation cannot be prevented.

(A) is sectional drawing which shows one Embodiment of the halftone type phase shift mask blank of this invention, (b) is sectional drawing which shows one Embodiment of the halftone type phase shift mask of this invention. (A) thru | or (e) is sectional drawing which shows the manufacturing process of the halftone type phase shift mask using the halftone type phase shift mask blank of this invention in order.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Light semi-transmissive film 2a Light semi-transmissive part 3 Light transmissive part 4 Resist film 10 Halftone type phase shift mask blank 20 Halftone type phase shift mask

Claims (7)

A halftone phase shift mask blank in which a light translucent film having a predetermined transmittance with respect to an exposure wavelength of 200 nm or less and having nitrogen, metal and silicon as main components is formed on a transparent substrate. ,
The surface layer of the light translucent film contains the nitrogen, metal, silicon, and oxygen, the nitrogen content is 45 atomic% or less, the oxygen content is 35 atomic% or more, and the metal content amount Ri der 5 atomic% or less,
The halftone phase shift mask blank characterized in that the nitrogen content in the surface layer of the light semi-transmissive film is less than the nitrogen content in the light semi-transmissive film excluding the surface layer . 2. The halftone phase shift mask blank according to claim 1, wherein the content of nitrogen in the light semi-transmissive film excluding the surface layer is 30 atom% to 70 atom%. The metal content in the light translucent film excluding the surface layer is 2 atomic% to 8 atomic%, and the silicon content is 20 atomic% to 50 atomic%. Halftone phase shift mask blank. The surface layer of the thickness of the halftone phase shift mask blank according to any one of claims 1 to 3, wherein the at 1nm or 5nm or less. The halftone phase shift mask blank according to any one of claims 1 to 4 , wherein the light semi-transmissive film excluding the surface layer does not substantially contain oxygen. The halftone type according to any one of claims 1 to 5, wherein the light semi-transmissive film has a phase shift amount of 160 to 200 degrees and a light transmittance of 2% to 20% with respect to exposure light. Phase shift mask blank. Patterning the light semi-transmitting film of the halftone phase shift mask blank according to any one of claims 1 to 6, the light semi-transmitting portion which on a transparent substrate, nitrogen, metals and silicon as main components A method for producing a halftone phase shift mask, characterized in that:

Images