JPH10171096A - Phase shift mask and phase shift mask blank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to obtain a halftone phase shifter film capable of controlling transmittance and refractive index in the near UV to deep UV region, by forming the film having the thickness to shift the phase of light by a prescribed quantity and light transmittance of a prescribed quantity, using silicon, carbon, etc., as main constitution elements and simultaneously incorporating Si-C bonds, etc., therein. SOLUTION: The basic required condition is that the use of the mask for the exposure wavelength region from UV to deep UV be made possible. The film material for halftone phase shifter which satisfys the basic condition and has light translucency even in the desired wavelength region while having an optical refractive index is obtd. by forming the constitution components of the phase shifterTtek filn of the silicon, carbon and nitrogen as the main constitution elements, Further, the phase shifter film 3 has the Si-C bonds, Si-N bonds, etc., in combination and these bonds form the matrix in the film, thereby making the fine structure of the film robust and improving the denseness of the film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase shift mask and a phase shift mask blank as its material, and more particularly to a halftone type phase shift mask and a phase shift mask blank.

[0002]

2. Description of the Related Art High integration of DRAMs, which started with 1 Mbit, has now reached the point where a mass production system for 16 Mbit DRAMs has been established. In this technological innovation, the exposure light source has been changed from g-line (436 nm) of ultra-high pressure mercury lamp to i-line (365 nm).
nm). At present, reduction of the exposure wavelength for higher integration is being studied. However, in the ordinary photolithography method, shortening the exposure wavelength improves resolution, but at the same time, reduces the depth of focus. This not only increases the burden on the design of the exposure optical system, but also causes a problem that the stability of the process is significantly reduced, and that the product yield is adversely affected.

The phase shift method is one of the super-resolution methods effective for such a problem. In the phase shift method, a phase shift mask is used as a mask for transferring a fine pattern.

A phase shift mask includes, for example, a phase shifter portion that forms a pattern portion on the mask and a non-pattern portion where no phase shifter exists. The phase shift mask shifts the phase of light passing through both by 180 °. Mutual interference of light is generated at a pattern boundary portion, and this effect improves the contrast of a transferred image. Furthermore, by using the phase shift method, it is possible to increase the depth of focus to obtain the required resolution, and compared with a transfer process using a normal mask having a general light shielding pattern made of a chrome film or the like. It is possible to improve resolution and process stability and applicability at the same time while using light of the same wavelength.

[0005] The phase shift mask is a perfect transmission type (Shibuya-Levenson type) depending on the light transmission characteristics of the phase shifter.
Practically, it can be roughly divided into a phase shift mask and a halftone type phase shift mask. The former is a mask in which the light transmittance of the phase shifter portion is equivalent to that of the non-pattern portion (light transmitting portion), and is almost transparent to the exposure wavelength, and is generally effective for line and space transfer. It is said. On the other hand, in the latter, the light transmittance of the phase shifter portion is about several percent to several tens of percent of the non-pattern portion (light transmitting portion), and is said to be effective for producing contact holes and isolated patterns in a semiconductor manufacturing process. ing.

FIG. 1 shows the basic structure of a halftone type phase shift mask blank, and FIG. 2 shows the basic structure of a halftone type phase shift mask. Note that an antireflection layer, an etching stop layer, and the like that may be used in a lithography process are omitted. The halftone type phase shift mask blank has a phase shifter film 2 formed on a transparent substrate 1. The halftone type phase shift mask has a phase shifter portion 3 for forming a pattern portion on the mask, It consists of a non-pattern part 4 that does not exist.

Among the halftone type phase shift masks, there is a single layer type halftone type phase shift mask which has a simple structure and is easy to manufacture. Such a single-layer halftone phase shift mask is disclosed in, for example,
One having a phase shifter made of a chromium-based material described in Japanese Patent No. 127361, a one having a phase shifter made of a MoSI-based material such as MoSiO and MoSiON described in JP-A-6-332152, and Japanese Unexamined Patent Publication No.
No. 1,816,664 having a phase shifter containing a transition metal such as W, Ta, Cr, etc. and Si, or a phase shifter comprising a SiN-based or SiO-based material described in JP-A-7-261370. And the like.

[0008]

The exposure wavelength has been shortened by the combined use with such a phase shift mask, and in recent years, excitation light of krypton fluoride (KrF) has been used as the shorter wavelength light. The use of KrF excimer laser light (248 nm) is being studied. In order to further shorten the wavelength, argon fluoride (ArF) excimer laser light (193 nm) or argon chloride (ArC) is used.
l) The use of excimer laser light (175 nm) has also been proposed.

With the shortening of the exposure wavelength, it is said that the wavelength range to be used shifts from ultraviolet to deep ultraviolet and further to vacuum ultraviolet. However, a corresponding phase shift mask and phase shift What is important in a mask blank is control of transmittance at the exposure wavelength to be used. Unlike in the visible to near ultraviolet region, the wavelength is 2
In the region shorter than 50 nm, the degree of light absorption is remarkably large in many substances, so that it is difficult to control the transmittance to a desired value. The setting of the transmittance in the phase shifter depends on the sensitivity of the resist used in pattern transfer and the type of mask (transmission type or halftone type). For example, in the case of a halftone type phase shift mask,
It is desirable that the transmittance of the exposure light can be controlled in the range of 4% to 20% at the thickness of the phase shifter that shifts the phase of the exposure light by a predetermined angle.

On the other hand, shortening the exposure wavelength means that the energy density applied per unit time increases at the same time. Correspondingly, the film material forming the phase shifter layer is required not to impair the function as a phase shift mask due to damage due to irradiation with high energy light. The damage here means changes in optical characteristics (refractive index, transmittance, etc.) of the shifter film due to light irradiation, generation of color defects, changes in film thickness, film quality deterioration, and the like. For example, when an excimer laser having a wavelength in the deep ultraviolet region is irradiated, a substance in the film is excited by a two-photon process, which is said to lead to a change in the optical properties and film quality of the film, but the details are still unclear. Has not been. In any case, one of the essential conditions is that the phase shifter film has high irradiation resistance in irradiation with high-energy light accompanying the shortening of the exposure wavelength.

Furthermore, when considering the material of the shifter film from the viewpoint of the mask material, the film must not be altered or dissolved by washing with an acid or alkali in the mask manufacturing process. That is, regardless of the length of the exposure wavelength,
The phase shifter film is required to have chemical durability.

Further, from the viewpoint that the phase shift mask is a tool for performing fine processing, it is necessary to have fine workability capable of achieving processing (patterning, etching, etc.) of the phase shift mask blank with higher precision. Therefore, it is required that the phase shifter film be uniform and have no defects in the film. It is said that the mask pattern will be further miniaturized as the exposure wavelength becomes shorter in the future, and defects in the phase shifter film will be an important problem that affects the reliability of pattern transfer. The term “defect” as used herein refers to fine particles or the like that are taken into the phase shifter film when the film is formed, and includes dust adhering to the substrate and dust (mechanical dust,
Film-peeling substance). in this case,
Needless to say, suppressing dust generated from substrates and devices is an effective solution. However, on the other hand, in the sputter film forming method, which is the most common method for producing a mask blank, it is said that abnormal discharge generated during sputtering and fine scattered particles generated by this cause a sudden increase in the number of defects in the phase shifter film. Efforts have been made to reduce abnormal discharge by controlling the device structure, power supply, target manufacturing method, sputtering gas, and the like. Some have pointed out that the cause of the abnormal discharge itself is the charge-up of insulating (oxidized) substances deposited and adhered to the inner wall of the chamber and the surface of the target during sputtering. Some attempts have been made to improve the charge-up by using the power supply function. There is, but it is hard to say. In any case, in the production of the phase shift mask blank in the future, there should be no defect such as introducing a defect into the phase shifter film on a mass production basis.

However, in the conventional halftone type phase shift mask and its blank, the above-mentioned problem corresponding to the shortening of the exposure wavelength has not been sufficiently addressed.

The present invention has been made under the above-described background, and satisfies all of the above-mentioned problems (required characteristics), and therefore can respond to a short exposure wavelength and a halftone type phase shift mask and a blank thereof. The purpose is to provide.

[0015]

Means for Solving the Problems To achieve the above object, a phase shift mask according to the present invention is (transfer mask) used for exposing and transferring a fine pattern.
A light transmitting part that transmits the exposure light, and a phase shifter part that shifts the phase of the light by a predetermined amount with respect to the light passing through the light transmitting part, and near a boundary between the light transmitting part and the phase shifter part By designing the optical characteristics so that the lights transmitted through each other cancel each other out, the contrast of the pattern boundary portion transferred to the surface of the object to be exposed can be maintained and improved. The phase shifter section has a thickness that shifts the phase of light by a predetermined amount with respect to the light transmitting section, and the phase shifter section has a predetermined amount of light transmittance with respect to the exposure light, and the phase shifter section Has silicon, carbon, and nitrogen as main components, and has a Si—C bond, a Si—N bond, and a C—N
Bond, Si-CN bond, C-Si-N bond, and Si
-Characterized by comprising a material containing simultaneously -NC bond,

Further, as an aspect of the above configuration, (Configuration 2)
As a material of the phase shifter portion, a configuration characterized by containing at least one of oxygen and hydrogen,

In the first and second aspects, (Constitution 3) As a material constituting the phase shifter portion, silicon is 5% to 65% and carbon is 5% to 5% in atomic percentage (at%). 70%, nitrogen 10% -80%, oxygen 0%
-30%, hydrogen is contained in the range defined in 0% -30%, and the total amount thereof occupies at least 80% or more of the whole composition constituting the phase shifter portion.

Further, as an aspect of the above-mentioned constitutions 1-3, (constitution 4) at least one selected from the group consisting of boron, phosphorus, molybdenum, tungsten, tantalum, titanium, chromium and other transition metals as a substance constituting the phase shifter portion. Or a type that contains

Further, according to the first to fourth aspects, (the fifth aspect) the transmittance of the phase shifter portion to the exposure light is 4%.
To 20%,

Further, as an aspect of the above-described constitutions 1 to 5, (constitution 6) is characterized in that it has a phase shifter portion designed so that it can be used for a wavelength of exposure light of 100 nm or more and 250 nm or less. Configuration,

Further, as an aspect of the above-mentioned constitutions 1 to 6, (constitution 7) a phase shifter portion designed to be usable for a wavelength of exposure light of 150 nm or more and 200 nm or less is characterized. The configuration is as follows.

Further, a phase shift mask blank of the present invention is (Structure 8) a phase shift mask blank used as a material of the phase shift mask according to any one of the structures 1 to 7, wherein Silicon, carbon, and nitrogen as main constituents, Si-C bond, Si-N bond, C
The present invention is characterized in that a thin film made of a material simultaneously containing a -N bond, a Si-CN bond, a C-Si-N bond and a Si-NC bond is formed.

Further, the pattern transfer method of the present invention is characterized in that (Structure 9) pattern transfer is performed using the phase shift mask according to any one of the structures 1 to 7.

In the present invention, Si—C bond, S
i-N bond, CN bond, Si-CN bond, C-Si
The symbol “-” in each bond type represented by a —N bond and a Si—NC bond means a bond between atoms, and is not limited to a single bond, but may be a multiple bond or any other bond. The bonding state (for example, a bond between a single bond and a double bond) and the like are also included.

[0025]

The basic condition of the present invention is that the phase shifter film can be used for a desired exposure light wavelength, for example, krypton excimer fluoride, for use in an exposure wavelength region from ultraviolet to deep ultraviolet. 2 which is the laser oscillation wavelength
It must be semi-transparent to 48 nm, or 193 nm, which is the oscillation wavelength of an argon fluoride excimer laser, or any other wavelength, and must be able to control this semi-transmissivity in film production. In addition, it must have an optical refractive index in addition to the light semi-transmissivity, and must be able to be controlled in the same manner as the light semi-transmission. The refractive index correlates with the thickness of the phase shifter to determine the phase shift angle, which is an important requirement of the phase shift mask. For example, when the refractive index is 2, the thickness at which a phase shift angle of 180 ° is obtained is 12 at a wavelength of 248 nm.
4 nm (× N: natural number), and a wavelength of 193 nm
Is 96.5 nm (× N: natural number). Accordingly, since a desired light semi-transmission is actually required on the premise that the film thickness condition for achieving the set phase shift angle is satisfied, it is very important to be able to control these numerical values.

On the other hand, according to the above configuration 1, by using silicon, carbon, and nitrogen as the main components of the phase shifter film, the above basic conditions required for the phase shifter film can be satisfied. It is possible to provide a film material for a halftone type phase shifter that has an optical refractive index and a light semi-transmissivity even in a desired wavelength region.

Further, in the phase shifter film, Si—C bond, Si—N bond, CN bond, Si—CN bond,
-Si-N bond and Si-NC bond in a complex form, and these bonds constitute a matrix in the film, thereby solidifying the fine structure of the film and improving the denseness of the film. In order to improve the film thickness, it is possible to suppress the film from being damaged by high-energy light, which is a problem due to irradiation with exposure light having a short wavelength. Here, the components of the film and the effects thereof will be described in detail. Silicon is bonded to carbon and nitrogen (Si-
C, Si-N, C-Si-N or a bond similar thereto) to form a main matrix in the film structure. Further, since a structure containing silicon is a main component of the film, it is possible to obtain a film having good adhesion to a quartz or glass substrate used as a base substrate. Similarly, carbon bonds primarily with silicon. The unit made of silicon carbide (Si-C) formed thereby improves the chemical durability of the film. Chemical durability is
For example, it is effective for a cleaning step using an acid or an alkali in a mask manufacturing process. This unit also contributes to the improvement of the electrical conductivity. Carbon is also Si-
A C—N bond is formed to make the structure of the film dense and solid. On the other hand, nitrogen bonds with silicon or carbon in the film. A unit made of silicon nitride (Si-N) combined with silicon improves the transmittance of the film to exposure light. Further, the unit made of Si—N can be easily etched under a general dry etching condition as compared with a quartz substrate, that is, improves a dry etching selectivity of a film as compared with a quartz substrate. Nitrogen partially bonds with carbon released in the film, and fixes carbon not directly bonded to silicon in the matrix of the film (C-N
Bond, C—N—Si bond). Further, the production conditions of the phase shifter film of the present invention can be arbitrarily controlled, and an amorphous film can be easily obtained. The fact that the film structure is amorphous means that the stress generated in the film can be appropriately controlled to a desired value,
Finally, in a lithography step of forming a mask by patterning, the workability of a fine pattern is significantly improved.

The phase shifter film is formed by a general film forming method such as a sputter film forming method, a chemical vapor deposition (CVD) method using heat or plasma, an ion beam deposition method, an evaporation method, Various thin film forming methods such as a line evaporation method can be used. Basically, which film formation method to use may be appropriately selected depending on the type and properties of the material or the desired film quality.However, in consideration of the breadth of controllability of the film quality and mass productivity, the current However, a sputtering method is preferred.

In the case of the sputtering film forming method, a substantial film component can be determined by a combination of a target and a sputtering gas. There are a wide variety of combinations, for example, when producing the phase shifter film of the present invention, silicon or a silicon-containing target is used as a sputtering target, and a carbon-containing gas such as methane, ethane, or propane is used as a sputtering gas. , Ethylene, acetylene, etc.,
With a gas containing nitrogen, for example, nitrogen, nitric oxide, nitrogen dioxide, nitrous oxide, laughing gas, ammonia gas,
It is possible to use a sputtering gas in which argon, xenon, hydrogen, oxygen, or a gas containing hydrogen or oxygen is mixed as appropriate. In addition, as a sputtering target, a target containing carbon or a target containing silicon nitride, or a target containing silicon carbide, and a composite target of these materials can be used.
As the sputtering gas at that time, a gas species that can add a component corresponding to the sputtering efficiency and finally the target film composition may be selected and mixed for use. The power application method, sputtering output, gas pressure, presence / absence of substrate heating, and the like during sputtering may be appropriately selected according to the material system to be used and the desired film characteristics.

According to the above configuration 2, the phase shifter film mainly composed of silicon, carbon, and nitrogen shown in the above configuration 1 further contains at least one of oxygen and hydrogen, so that its optical characteristics can be improved. The range of characteristic control expands.
Most of the oxygen in the phase shifter film comes from outside the film during the film formation except for an oxide film formed on the film surface after the film formation. In particular, oxygen introduced during sputtering film formation forms an insulating oxide on the target surface or the inner wall of the apparatus, and induces abnormal discharge. Oxygen itself bonds with silicon in the film and improves light transmittance especially in the vicinity of the visible region, but is intentionally introduced as a sputtering gas to produce a high-quality film with less defects in the film. It is better to suppress as much as possible, including the case of doing. Hydrogen is also useful in terms of improving light transmittance and fine workability, but it is necessary to determine the amount of hydrogen to be introduced in consideration of thermal stability and photochemical stability in the film.

In a mask design (mask structure) in which a desired phase shifter pattern is arranged on the surface of a transparent substrate, a desired optical design is performed by subjecting a phase shifter layer on a phase shift mask blank to fine processing by a lithography method. A filled halftone phase shift mass can be easily produced. As a lithography method, a method used in a general mask manufacturing process can be applied. For example, for patterning of a phase shifter layer on a phase shift mask blank, CF ₄ , C ₂ F ₆ , CHF ₃ , S
Fluorine-containing gas such as F ₆ and NF ₃ , Cl ₂ , CH ₂ C
A dry etching method using a gas containing chlorine such as l ₂ and an etching gas such as a gas containing oxygen such as O ₂ , O ₃ , and H ₂ O can be suitably used. In the dry etching, argon, hydrogen, helium,
Alternatively, it is also effective to control the etching characteristics by using another gas mixed with the above-mentioned etching gas.

According to the above configuration 3, it is possible to obtain a desired and suitable film material within the range of the ratio of each constituent element shown in the configuration 3. That is, when silicon is less than 5%, the bond between silicon and carbon, nitrogen, etc. is small, and it is difficult to improve the denseness of the film. When silicon is more than 65%, the silicon alone exists in the film. Increase the proportion of silicon
The chemical durability and optical properties of the film may be reduced.
When the carbon content is less than 5%, the bond between silicon and carbon is reduced, and the chemical durability is reduced. When the carbon content is more than 70%, the controllability of the optical coefficient may be reduced. Further, if the nitrogen content is less than 10%, it cannot contribute to the improvement of the transmittance, and if the nitrogen content is more than 80%, the ratio of excess nitrogen in the film increases, and the film becomes unstable, This may cause nitrogen in the film to escape.

Further, in the case where at least one of oxygen and hydrogen is contained, if the oxygen content is more than 30%, abnormal discharge which induces defects in the film is likely to occur. On the other hand, if the amount of hydrogen is more than 30%, the film becomes unstable in the film, which may cause the hydrogen in the film to escape.

According to the above configuration 4, as a substance constituting the phase shifter film, as a substance other than the main constituent material,
By containing at least one selected from boron, phosphorus, molybdenum, tungsten, tantalum, titanium, chromium and other transition metals, improvement in film properties,
For example, the addition of a metal is effective for improving the conductivity of the film, improving the transmittance in the visible light region (inspection light wavelength region), and controlling other optical characteristics. Therefore, a more suitable film material is obtained. It becomes possible.

According to the above configuration 5, by setting the transmittance of the phase shifter film to the exposure light in the range of 4% to 20%, a sufficient halftone type phase shift mask can be obtained.

According to the above configuration 6, the wavelength of the exposure light is 10
By having a phase shifter film designed to be usable for a wavelength of 0 nm to 250 nm, a short wavelength light source such as the above-described krypton fluoride excimer laser, argon fluoride excimer laser, and argon chloride excimer laser is provided. Can be suitably used as a halftone type phase shift mask for photolithography using as a light source, in particular, when the wavelength of the exposure light is 150 nm to 20 nm.
At 0 nm, all the effects described above are maximized.

According to the above configuration 8, a phase shift mask blank suitable for manufacturing a phase shift mask usable in the above-mentioned short wavelength region can be obtained. According to the above configuration 9, the above short wavelength exposure can be performed. Pattern transfer using light can be realized.

[0038]

Hereinafter, the present invention will be described more specifically based on examples.

Example 1 In Example 1, a mixture of Si ₃ N ₄ powder and single-crystal Si powder mixed at a weight ratio of about 4: 1 and sintered was used as a sputtering target. ₂ and CH ₄ about 2
A gas mixed at a ratio of 3: 4 was used as a sputtering gas. The conditions for introducing the sputtering gas were set so that the total amount of the mixed gas introduced was 40 SCCM, and the pressure in the apparatus at the time of sputtering was 3 mTorr by a pressure regulator immediately above the exhaust pump.

The formation of the halftone phase shifter film was performed on a quartz substrate by DC sputter discharge. In order to perform DC discharge, it is a necessary condition that the sputter target has a certain degree of conductivity, but the material forming the target is a semi-insulator or a non-conductor (non-conductor).
When direct current discharge is difficult as described above, a material that imparts conductivity to the target, for example, boron or the like may be used in an amount that does not particularly hinder the characteristics of the finally formed halftone phase shifter film. It may be added. Regarding the discharge method, it is substantially possible to use a high-frequency discharge method in which plasma discharge is hardly affected by the conductivity of the target and an AC discharge method, in addition to the DC discharge. However, in any case, it is important to minimize defects in the film when manufacturing a desired film.

The gas used for sputtering is not limited to the above substances and the mixing ratio.
Xe gas in place of r, NH ₃ , N in place of N ₂
A gas containing nitrogen such as ₂ O, NO ₂ , NO; a gas containing carbon such as C ₂ H ₄ , C ₂ H ₂ , CO, CO ₂ instead of CH ₄ , or an inert gas thereof; It is possible to appropriately select a gas containing nitrogen and a gas containing carbon, and use them as a mixture. However, as described above, in order to reduce the deposition amount of the insulating oxide formed during the sputter discharge and thereby suppress the abnormal discharge induced by the sputtering to obtain a film with few defects, the oxygen content must be reduced. It is desirable to use a mixed gas system that minimizes the pressure.

The film thickness of the halftone phase shifter film thus formed on the quartz substrate was measured by a stylus method and the transmittance was measured by a spectrophotometer.
It was 5 angstroms (FIG. 2) and the spectral transmittance at 193 nm was 7.2% (FIG. 3). Similarly, when the refractive index (n) was calculated from the reflectance, transmittance, and film thickness of the film measured using a spectrophotometer, the refractive index (n) was 2.
43 and 193 nm at a film thickness of 675 angstroms.
Is sufficient to shift the phase of light of the wavelength of 180 ° by 180 °.

The chemical durability of the produced halftone phase shifter film was evaluated by immersion in an acid and a change in film quality before and after immersion. 675 angstroms, 193
The above halftone phase shifter film having a spectral transmittance of 7.2% in nm was immersed in hot concentrated sulfuric acid heated to 90 ° C. for 120 minutes, and measured in the same manner as above.
The film thickness was 672 angstroms, the spectral transmittance at 193 nm was 7.3%, and the phase shift angle shift caused by immersion in acid was within 1 °, indicating that the film had sufficient resistance to hot concentrated sulfuric acid. There was no change in film quality before and after immersion. Similarly, when immersed in a solution of hydrogen peroxide and sulfuric acid in a ratio of 1: 4 at a temperature of 120 ° C. for 120 minutes, it was confirmed that the solution had sufficient chemical resistance.

With respect to the light irradiation resistance of the manufactured halftone phase shifter film, A having an oscillation wavelength of 193 nm was used.
Irradiation with an rF excimer laser was performed to evaluate the transmittance, the refractive index, and the film thickness of the film before and after the irradiation. As a result, there was no significant change in transmittance, refractive index, and film thickness before and after irradiating 10,000 pulses of an ArF excimer laser having an irradiation energy density of 13.5 mJ / cm ² per single pulse. Its properties as a shifter membrane were very stable.

The etching of the produced halftone phase shifter film was performed by reactive ion etching. At this time, a gas in which C ₂ F ₆ and oxygen were mixed at a flow ratio of 1: 3 was used as an etching gas. As a result, it was confirmed that satisfactory etching could be performed while having an etching selectivity of 5 to 6 times that of the quartz substrate. Further, since the film structure was amorphous, the side walls of the etching pattern were also smooth. Note that the etching of the phase shifter film is not limited to the above method, and an etching method, an etching gas, and detailed etching conditions may be optimally selected and set.

As shown in Example 1 above, it was possible to easily produce a thin film having both good film quality and optical characteristics as a halftone phase shifter film.

Example 2 In Example 2, SiC and C were used as sputtering targets.
And a gas obtained by mixing Ar and N ₂ at a ratio of about 1 to 6 was used as a sputtering gas. The sputtering gas introduction conditions were such that the total introduction amount of the mixed gas was 40 SC.
After setting to CM, the pressure in the apparatus at the time of sputtering was set to 3 mTorr by a pressure regulator immediately above the exhaust pump.

The formation of the halftone phase shifter film was performed on a quartz substrate by DC sputtering discharge. The discharge method and sputtering gas are not limited to those described above, and can be appropriately selected as in the first embodiment. For example, as a discharge method, a high frequency sputtering method, an AC sputtering method, or the like can be used. Regarding the sputtering gas, a gas containing nitrogen such as NH ₃ , N ₂ O, NO ₂ , NO, or the like, or an inert gas and nitrogen is used instead of Ar for Xe gas and N _2. It is possible to appropriately select and mix the gases to be contained from the viewpoint of reducing the oxygen fraction as much as possible. Therefore, it is only necessary to use a sputtering method and a sputtering gas material that are optimal for achieving the object.

The film thickness of the halftone phase shifter film thus formed on the quartz substrate was measured by a stylus method and the transmittance was measured by a spectrophotometer.
It was 4 angstroms and the spectral transmittance at 193 nm was 6.0%. When the refractive index (n) was calculated from the reflectance, transmittance, and film thickness of the film similarly measured using a spectrophotometer, the refractive index (n) was 2.20 and the film thickness was 8
It was confirmed that it was sufficient to shift the phase of light having a wavelength of 193 nm at 180 Å by 180 °.

The chemical durability of the produced halftone phase shifter film was evaluated based on changes in film quality and optical characteristics before and after immersion in an acid, as in Example 1.
As a result, in any immersion in hot concentrated sulfuric acid and perhydrogen sulfuric acid solution, the resulting shift in phase shift angle is 2 ° or less, and the change in transmittance is 0.5% or less,
It was confirmed that it had sufficient chemical resistance.

With respect to the light irradiation resistance of the produced halftone phase shifter film, an ArF excimer having an oscillation wavelength at 193 nm and an irradiation energy density per single pulse of 13.5 mJ / cm ² , as in Example 1. Changes in transmittance, refractive index, and film thickness were measured before and after the irradiation of 10,000 pulses of the laser, but no significant difference was observed in the measured values, and the characteristics of the halftone phase shifter film were very stable.

The etching of the produced halftone phase shifter film was performed by reactive ion etching in the same manner as in Example 1. At this time, CHF is used as an etching gas.
_A gas in which ₃ and oxygen were mixed at a flow ratio of 1: 2.5 was used. As a result, it was confirmed that etching could be favorably performed while having an etching selectivity of 4 to 7 times the quartz substrate. Note that the etching of the phase shifter film is not limited to the above method, and an etching method, an etching gas, and detailed etching conditions may be optimally selected and set.

As shown in the second embodiment, the second embodiment
As in Example 1, it was possible to easily produce a thin film having both good film quality and optical characteristics as a halftone phase shifter film as in Example 1.

Example 3 In Example 3, a target made of Si was used as a sputtering target, and a gas obtained by mixing Ar, N ₂ and CH ₄ at a ratio of about 1: 5: 5 was used as a sputtering gas. The conditions for introducing the sputtering gas were set so that the total amount of the mixed gas introduced was 40 SCCM, and the pressure in the apparatus at the time of sputtering was 3 mTorr by a pressure regulator immediately above the exhaust pump.

The formation of the halftone phase shifter film was performed on a quartz substrate by DC sputtering discharge. The discharge method and sputtering gas are not limited to those described above, and can be appropriately selected as in the first embodiment. For example, as a discharge method, a high frequency sputtering method, an AC sputtering method, or the like can be used. Further, with regard sputtering gas, a Xe gas instead of Ar, NH ₃ instead of N _2, N ₂ O, a gas containing nitrogen such as _{NO 2, NO, C 2 H} 4 in place of CH _4, C A gas containing carbon such as ₂ H ₂ , CO, CO ₂ or an inert gas thereof;
The nitrogen-containing gas and the carbon-containing gas can be appropriately selected from the viewpoint of reducing the oxygen content as much as possible, and can be used as a mixture. Therefore, it is only necessary to use a sputtering method and a sputtering gas material that are optimal for achieving the object.

The film thickness of the halftone phase shifter film thus formed on the quartz substrate was measured by a stylus method and the transmittance was measured by a spectrophotometer.
It was 0 angstroms and the spectral transmittance at 193 nm was 5.7%. Also, when the refractive index (n) was calculated from the reflectance, transmittance, and film thickness of the film similarly measured using a spectrophotometer, the refractive index (n) was 2.36 and the film thickness was 7
It was confirmed that it was sufficient to shift the phase of light having a wavelength of 193 nm by 180 ° at 10 Å.

As in Example 1, the chemical durability of the produced halftone phase shifter film was evaluated based on changes in film quality and optical characteristics before and after immersion in an acid.
As a result, in any immersion in hot concentrated sulfuric acid and perhydrogen sulfuric acid solution, the resulting shift in phase shift angle is 2 ° or less, and the change in transmittance is 0.5% or less,
It was confirmed that it had sufficient chemical resistance.

Regarding the light irradiation resistance of the produced halftone phase shifter film, as in Example 1, an ArF excimer having an oscillation wavelength at 193 nm and an irradiation energy density per pulse of 13.5 mJ / cm ² was used. Changes in transmittance, refractive index, and film thickness were measured before and after the irradiation of 10,000 pulses of the laser, but no significant difference was observed in the measured values, and the characteristics of the halftone phase shifter film were very stable.

The etching of the produced halftone phase shifter film was performed by reactive ion etching in the same manner as in Example 1. At this time, C ₂ F _{6 is used} as an etching gas.
A gas in which oxygen and oxygen were mixed at a flow ratio of 1: 3 was used. As a result, it was confirmed that satisfactory etching could be performed while having an etching selectivity four times or more that of the quartz substrate. In addition, the etching of the phase shifter film is not limited to the above-described method, and may include an etching method, an etching gas,
Further, it is only necessary to optimally select and set detailed etching conditions and the like.

As shown in the third embodiment, the third embodiment
As in Example 1, it was possible to easily produce a thin film having both good film quality and optical characteristics as a halftone phase shifter film as in Example 1.

Example 4 In Example 4, a target composed of Si ₃ N ₄ and SiC was used as a sputtering target, and Ar, N ₂ and CH ₄ were mixed at a ratio of about 1: 1: 1 as a sputtering gas. The used gas was used. The sputtering gas was introduced under the conditions that the total amount of the mixed gas was set to 40 SCCM, and the pressure in the apparatus at the time of sputtering was 3 mTorr by a pressure regulator immediately above the exhaust pump.
It was set to be.

The formation of the halftone phase shifter film was performed on a quartz substrate by DC sputtering discharge. The discharge method and sputtering gas are not limited to those described above, and can be appropriately selected as in the first embodiment. For example, as a discharge method, a high frequency sputtering method, an AC sputtering method, or the like can be used. Further, with regard sputtering gas, a Xe gas instead of Ar, NH ₃ instead of N _2, N ₂ O, a gas containing nitrogen such as _{NO 2, NO, C 2 H} 4 in place of CH _4, C A gas containing carbon such as ₂ H ₂ , CO, CO ₂ or an inert gas thereof;
The nitrogen-containing gas and the carbon-containing gas can be appropriately selected from the viewpoint of reducing the oxygen content as much as possible, and can be used as a mixture. Therefore, it is only necessary to use a sputtering method and a sputtering gas material that are optimal for achieving the object.

The film thickness of the halftone phase shifter film thus formed on the quartz substrate was measured by a stylus method and the transmittance was measured by a spectrophotometer.
It was 6 angstroms and the spectral transmittance at 193 nm was 8.5%. Also, when the refractive index (n) was calculated from the reflectance, transmittance, and film thickness of the film similarly measured using a spectrophotometer, the refractive index (n) was 2.62, and the film thickness was 5%.
It was confirmed that it was sufficient to shift the phase of light having a wavelength of 193 nm by 180 ° at 96 Å.

The chemical durability of the produced halftone phase shifter film was evaluated based on changes in film quality and optical characteristics before and after immersion in an acid, as in Example 1.
As a result, in any immersion in the hot concentrated sulfuric acid and the persulfuric acid solution, the resulting shift in the phase shift angle is 2 ° or less, and the change in the transmittance is 0.8% or less,
It was confirmed that it had sufficient chemical resistance.

With respect to the light irradiation resistance of the produced halftone phase shifter film, an ArF excimer having an oscillation wavelength of 193 nm and an irradiation energy density per single pulse of 13.5 mJ / cm ² , as in Example 1. Changes in transmittance, refractive index, and film thickness were measured before and after the irradiation of 10,000 pulses of the laser, but no significant difference was observed in the measured values, and the characteristics of the halftone phase shifter film were very stable.

The etching of the produced halftone phase shifter film was performed by reactive ion etching in the same manner as in Example 1. At this time, C ₂ F _{6 is used} as an etching gas.
A gas in which oxygen and oxygen were mixed at a flow ratio of 1: 3 was used. As a result, it was confirmed that satisfactory etching could be performed while having an etching selectivity four times or more that of the quartz substrate. In addition, the etching of the phase shifter film is not limited to the above-described method, and may include an etching method, an etching gas,
Further, it is only necessary to optimally select and set detailed etching conditions and the like.

As shown in the fourth embodiment, the fourth embodiment
As in Example 1, it was possible to easily produce a thin film having both good film quality and optical characteristics as a halftone phase shifter film as in Example 1.

Example 5 In Example 5, Si and Si were used as sputtering targets.
Using a target composed of C and A as a sputtering gas
A gas in which r and N ₂ were mixed at a ratio of about 1: 4 was used.
The conditions for introducing the sputtering gas are as follows:
After setting to SCCM, the pressure in the apparatus at the time of sputtering was set to 3 mTorr by a pressure regulator immediately above the exhaust pump.

The halftone phase shifter film was formed on a quartz substrate by DC sputtering discharge. The discharge method and sputtering gas are not limited to those described above, and can be appropriately selected as in the first embodiment. For example, as a discharge method, a high frequency sputtering method, an AC sputtering method, or the like can be used. Regarding the sputtering gas, a gas containing nitrogen such as NH ₃ , N ₂ O, NO ₂ , NO, or the like, or an inert gas and nitrogen is used instead of Ar for Xe gas and N _2. It is possible to appropriately select and mix the gases to be contained from the viewpoint of reducing the oxygen fraction as much as possible. Therefore, it is only necessary to use a sputtering method and a sputtering gas material that are optimal for achieving the object.

The film thickness of the halftone phase shifter film thus formed on the quartz substrate was measured by a stylus method and the transmittance was measured by a spectrophotometer.
It was 2 angstroms and the spectral transmittance at 193 nm was 5.5%. When the refractive index (n) was calculated from the reflectance, transmittance, and film thickness of the film similarly measured using a spectrophotometer, the refractive index (n) was 2.25, and the film thickness was 7
It was confirmed that the phase of light having a wavelength of 193 nm at 72 Å was sufficient to shift the phase by 180 °.

The chemical durability of the produced halftone phase shifter film was evaluated based on changes in film quality and optical characteristics before and after immersion in an acid, as in Example 1.
As a result, the shift of the phase shift angle caused by the immersion in both the hot concentrated sulfuric acid and the perhydrogen sulfuric acid solution is 1.7.
° or less, and the change in transmittance was 0.6% or less, confirming that the composition had sufficient chemical resistance. Regarding the light irradiation resistance of the manufactured halftone phase shifter film, it has an oscillation wavelength at 193 nm, as in Example 1.
Irradiation energy density per single pulse is 13.5 mJ /
Changes in transmittance, refractive index, and film thickness were measured before and after irradiating an ArF excimer laser of 10,000 cm ² with 10,000 pulses, but no significant difference was observed in the measured values, and the characteristics of the halftone phase shifter film were very low. It was stable.

The etching of the produced halftone phase shifter film was performed by reactive ion etching in the same manner as in Example 1. At this time, C ₂ F _{6 is used} as an etching gas.
A gas in which oxygen and oxygen were mixed at a flow ratio of 1: 3 was used. As a result, it was confirmed that satisfactory etching could be performed while having an etching selectivity four times or more that of the quartz substrate. In addition, the etching of the phase shifter film is not limited to the above-described method, and may include an etching method, an etching gas,
Further, it is only necessary to optimally select and set detailed etching conditions and the like.

As shown in the fifth embodiment, the fifth embodiment
As in Example 1, it was possible to easily produce a thin film having both good film quality and optical characteristics as a halftone phase shifter film as in Example 1.

Example 6 In Example 6, a target composed of Si ₃ N ₄ and Ta was used as a sputtering target, and Ar, N ₂ and CH ₄ were mixed at a ratio of about 1: 2: 2 as a sputtering gas. The used gas was used. The conditions for introducing the sputtering gas were set so that the total amount of the mixed gas introduced was 40 SCCM, and the pressure in the apparatus at the time of sputtering was 3 mTorr by a pressure regulator immediately above the exhaust pump.

The formation of the halftone phase shifter film was performed on a quartz substrate by DC sputter discharge. The discharge method and sputtering gas are not limited to those described above, and can be appropriately selected as in the first embodiment. For example, as a discharge method, a high frequency sputtering method, an AC sputtering method, or the like can be used. Further, with regard sputtering gas, a Xe gas instead of Ar, NH ₃ instead of N _2, N ₂ O, a gas containing nitrogen such as _{NO 2, NO, C 2 H} 4 in place of CH _4, C A gas containing carbon such as ₂ H ₂ , CO, CO ₂ or an inert gas thereof;
The nitrogen-containing gas and the carbon-containing gas can be appropriately selected from the viewpoint of reducing the oxygen content as much as possible, and can be used as a mixture. Therefore, it is only necessary to use a sputtering method and a sputtering gas material that are optimal for achieving the object.

The film thickness of the halftone phase shifter film thus formed on the quartz substrate was measured by a stylus method and the transmittance was measured by a spectrophotometer.
It was 9 angstroms and the spectral transmittance at 193 nm was 4.0%. When the refractive index (n) was calculated from the reflectance, transmittance, and film thickness of the film similarly measured using a spectrophotometer, the refractive index (n) was 2.51 and the film thickness was 6
It was confirmed that it was enough to shift the phase of light having a wavelength of 193 nm by 180 ° at 39 Å.

The chemical durability of the produced halftone phase shifter film was evaluated based on changes in film quality and optical characteristics before and after immersion in an acid as in Example 1.
As a result, the shift of the phase shift angle caused by both immersion in the hot concentrated sulfuric acid and the persulfuric acid solution is 1.5 times.
° or less, and the change in transmittance was 0.5% or less, confirming that the composition had sufficient chemical resistance.

Regarding the light irradiation resistance of the produced halftone phase shifter film, an ArF excimer having an oscillation wavelength of 193 nm and an irradiation energy density per single pulse of 13.5 mJ / cm ² , as in Example 1. Changes in transmittance, refractive index, and film thickness were measured before and after the irradiation of 10,000 pulses of the laser, but no significant difference was observed in the measured values, and the characteristics of the halftone phase shifter film were very stable.

The etching of the produced halftone phase shifter film was performed by reactive ion etching in the same manner as in Example 1. At this time, SF _{6 is used} as an etching gas.
A gas in which oxygen and oxygen were mixed at a flow ratio of 1: 3 was used. As a result, it was confirmed that satisfactory etching could be performed while having an etching selectivity of 5 times or more with respect to the quartz substrate. In addition, the etching of the phase shifter film is not limited to the above-described method, and may include an etching method, an etching gas,
Further, it is only necessary to optimally select and set detailed etching conditions and the like.

As shown in the sixth embodiment, the sixth embodiment
As in Example 1, it was possible to easily produce a thin film having both good film quality and optical characteristics as a halftone phase shifter film as in Example 1.

In any of the examples, it was confirmed that the present invention can be easily processed, and that the present invention has sufficiently high mass productivity in the production of a phase shift mask blank and a phase shift mask.

FIGS. 4 to 6 show the ESCA (Electron Spectro) of the halftone phase shifter film manufactured in the above embodiment.
scopy for Chemical Analysis). First, focusing on nitrogen in FIG. 4 and identifying the binding energy and the binding state from its characteristic peak (N1s), 397.4e
Si ₃ N ₄ having a peak at V can be detected. Further, the broadening of the peak indicates the presence of a bonding species of silicon and nitrogen expressed in a so-called Si-N state. Focusing on the characteristic peak (Si2p) of silicon in FIG.
Si ₃ N ₄ present at 1.6 eV, SiC present at 100.4 eV, and nitrides distributed before and after each,
Carbide and Si-C- having these as bonding species
It is clear that the N-bond, the C-Si-N bond, the Si-NC bond, and the signal due to silicon on the low energy side are superimposed. Further, as shown in FIG. 6, as a result of analysis focusing on the characteristic peak (C1s) of carbon, a signal from a bond represented by C—N distributed on the high energy side and a signal from carbon, graphite, or C—C are used. The signal from the represented bond and the Si present at 283.3 eV
-C and the carbide or Si-CN bond, C-Si-N bond and Si-N
It is clear that the signal from the -C coupling is superimposed. As described above, the halftone phase shifter film according to the present invention is a film having bonding species represented by Si—N, Si—C, and CN, and these bonding species have a certain ratio in the film. It is a film that exists in

The present invention has been described with reference to the embodiments.
The embodiment shown above is an example embodying the present invention,
The present invention is not limited by the conditions and the contents of execution.

For example, in the embodiments, instead of the quartz substrate, fluorite or other various glass substrates (for example, hydrofluoric acid-based glass, fluoroborate-based glass, etc.) may be used as the transparent substrate.

[0085]

As described above, according to the present invention, a halftone phase shifter film whose transmittance and refractive index can be controlled in the near ultraviolet to extreme ultraviolet region can be obtained. The tone phase shifter film is stable against high-energy short-wavelength light, has sufficient resistance to the chemicals used in the mask manufacturing process, has few defects in the film, and is fine. It is possible to easily provide an excellent phase shift mask which is excellent in processability, and thus can cope with a shorter wavelength of exposure light, and a phase shift mask blank as a material thereof under high mass productivity.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a halftone type phase shift mask blank.

FIG. 2 is a schematic sectional view showing a halftone type phase shift mask.

FIG. 3 is a diagram showing the spectral transmittance of the halftone phase shifter film in Example 1 in the ultraviolet to visible light region, and FIG. 3 (b) is a partially enlarged view of FIG. 3 (a).

FIG. 4 is a diagram showing an ESCA analysis result focusing on nitrogen of a halftone phase shifter film in an example.

FIG. 5 is a diagram showing an ESCA analysis result focusing on silicon of the halftone phase shifter film in the example.

FIG. 6 is a diagram showing an ESCA analysis result focusing on carbon of a halftone phase shifter film in an example.

[Description of Signs] 1 Transparent substrate 2 Phase shifter film 3 Phase shifter part 4 Non-pattern part

Claims (9)

[Claims] 1. A transfer mask used for performing exposure and transfer of a fine pattern, wherein the transfer mask transmits an exposure light, and shifts a phase of light by a predetermined amount with respect to light passing through the light transmission unit. By having a phase shifter portion to be made, by designing the optical characteristics so that the light transmitted through each of the light transmission portion and the boundary portion between the phase shifter portion cancel each other out,
In a phase shift mask capable of satisfactorily maintaining and improving the pattern boundary portion contrast transferred to the surface of the object to be exposed, the thickness of the phase shifter portion for shifting the phase of light by a predetermined amount with respect to the light transmitting portion is set. And the phase shifter section has a predetermined amount of light transmittance with respect to the exposure light, and the constituent components of the phase shifter section include at least silicon, carbon, and nitrogen as main components, and have a Si—C bond, Si −
N bond, CN bond, Si-CN bond, C-Si-N
A phase shift mask comprising a material containing a bond and a Si-NC bond at the same time. 2. The phase shift mask according to claim 1, further comprising at least one of oxygen and hydrogen as a material of the phase shifter. 3. The substance constituting the phase shifter section,
In each atomic percentage, silicon is 5% to 65%, carbon is 5% to 70%, nitrogen is 10% to 80%, and oxygen is 0% to 3%.
0%, containing hydrogen in a range defined by 0% to 30%,
3. The phase shift mask according to claim 1, wherein the total amount occupies at least 80% or more of the entire composition constituting the phase shifter. 4. The substance constituting the phase shifter section,
4. It contains at least one selected from the group consisting of boron, phosphorus, molybdenum, tungsten, tantalum, titanium, chromium and other transition metals.
The phase shift mask according to any one of the above, 5. The phase shift mask according to claim 1, wherein a transmittance of the phase shifter to the exposure light is in a range of 4% to 20%. 6. The wavelength of the exposure light is 100 nm or more and 250 n.
The phase shift mask according to any one of claims 1 to 5, further comprising a phase shifter unit designed to be used for a wavelength of m or less. 7. The wavelength of the exposure light is 150 nm or more and 200 n.
The phase shift mask according to any one of claims 1 to 6, further comprising a phase shifter designed to be used for a wavelength of m or less. 8. A phase shift mask blank used as a material of the phase shift mask according to claim 1, wherein silicon, carbon, and nitrogen are main components on a transparent substrate, C bond, Si-N bond, CN bond, Si-
A phase shift mask blank, wherein a thin film made of a material simultaneously containing a CN bond, a C-Si-N bond, and a Si-NC bond is formed. 9. A pattern transfer method using the phase shift mask according to claim 1 for pattern transfer.