KR20110044123A - Blankmask, photomask and manufacturing method of the same - Google Patents

Abstract

PURPOSE: A blank mask, photo mask and manufacturing method thereof are provided to control the uniformity of the composition ratio of a sputtering target and a thin film, thereby providing a blank mask with superior properties. CONSTITUTION: A transparent substrate(10) is prepared. A light shielding film(20) is formed on the transparent substrate. A reflection preventing film(30) is formed on the light shielding film. A hard mask film(40) is formed on the reflection preventing film. The surface of the hard mask film is processed. A resist film is formed on the hard mask film.

Description

Blank mask, photomask and manufacturing method thereof {Blankmask, Photomask and Manufacturing Method of the same}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a blankmask capable of implementing a high precision critical dimension (CD) in a semiconductor lithography process. In particular, the present invention relates to a blank mask capable of realizing a minimum linewidth of 65 nm or less, particularly 45 nm. 193 nm) lithography and ArF immersion lithography.

In line with the demand for miniaturization of circuit patterns associated with the high integration of large scale integrated circuits, advanced semiconductor microprocessing technology has become a very important factor. In the case of high integrated circuits, circuit wiring has been miniaturized for low power and high speed operation, and technical requirements for contact hole patterns for interlayer connection and arrangement of circuit configurations due to integration are increasing. Therefore, in order to meet these requirements, even in the manufacture of a photomask in which a circuit pattern is recorded, a technique capable of recording a more precise circuit pattern with the above miniaturization is required.

In particular, in order to form a precise circuit pattern, a blank mask structure has been developed that etches a lower metal film by using an inorganic hard mask film as an etching mask instead of using an existing resist film as an etching mask. It is becoming. This hard mask film replaces the existing thick resist film to improve the aspect ratio and improve the selectivity, thereby reducing the loading effect when etching the metal film. Excellent CD Mean to Target (MTT), CD Linearity To make it possible.

Meanwhile, in order to form the micronized pattern, the importance of the cleaning process for removing defects is gradually increased. In this regard, in recent years, as well as the existing SC 1 and SPM, cleaning technology using ozone water has been achieved. Ozone water can remove not only the organic matters on the surface but also the inorganic matters due to the stronger oxidation compared to the existing SPM, replacing the photoresist removal process and the cleaning solution for removing defects on the surface of metal film and hard mask film using SPM. Much research has been made on the cleaning solution that can be used.

However, the strong oxidation of ozone water during the removal and cleaning of the resist film using ozone water not only removes the resist film but also damages the lower layer, resulting in a change in thin film properties, making it difficult to manufacture a photomask having excellent quality. do. For example, in the case of the current metal film under the resist film, the chemical resistance to the ozone water chemical is significantly lowered, and thus the optical density, reflectance, and thickness of the metal film are changed, which causes light blocking and antireflection during wafer printing after photomask fabrication. There is a problem that the function is not excellent.

In addition, the remaining resist residues on the surface of the metal layer and the hard mask layer after forming the resist pattern under clear CD during the final pattern formation, making it difficult to form an excellent resolution.

The present invention provides a blank mask including a binary blank mask, a phase inversion blank mask, and a hard mask film used in ArF lithography and ArF immersion lithography, to solve the above problems. The metal film, the phase inversion film, and the hard mask film provide a blank mask having excellent chemical resistance to ozone water.

In order to achieve the above object, the features of the binary blank mask manufacturing method according to the present invention are as follows.

a1) preparing a transparent substrate;

b1) forming a metal film on the transparent substrate prepared in step a1);

c1) surface treating the metal film prepared in step b1); And

and d1) forming a resist film on the metal film surface-treated in step c1).

Another feature of the blank mask manufacturing method for a hard mask according to the present invention is as follows.

a1) preparing a transparent substrate;

b1) forming a metal film on the transparent substrate prepared in step a1);

e1) forming a hard mask film on the metal film formed in step b1);

f1) surface treating the hard mask film formed in step e1); And

g1) forming a resist film on the hard mask film surface-treated in step f1).

In the above manufacturing process, the blank mask and the binary blank mask including the hard mask may optionally include a phase inversion film.

The phase inversion film may be formed as a single layer or a multilayer, and in order to have excellent chemical resistance to ozone water, the total content of the metal or the transition metal in the composition ratio of the thin film is 1 to 10 at% or less. Ozone water causes damage to the metal or transition metal components included in the phase inversion film due to the strong oxidation effect. Such damage affects the transmittance and the amount of phase inversion of the phase inversion film, thereby changing the transmittance and phase inversion amount for the predetermined phase inversion, making it difficult to form a phase inversion film having excellent characteristics. Therefore, in order to improve the chemical resistance against such ozone water washing, the total content of the metal or the transition metal included in the phase inversion film is preferably 10 at% or less. However, when the content of the metal or the transition metal component is 1 at% or less, it is difficult to control the transmittance during the formation of the phase inversion film, thereby causing a problem in that the loading effect occurs due to a predetermined thickness or more. The loading effect causes CD deviation during dry etching according to pattern density and pattern size, and thus does not form an excellent CD MTT. Therefore, the phase inversion film preferably has a metal or transition metal component of 1 to 10 at% in the phase inversion film in order to simultaneously satisfy chemical resistance to ozone water, and optical properties of transmittance and phase inversion amount.

When the phase inversion film is formed on the binary blank mask, an etch stop layer may be formed between the transparent substrate and the phase inversion film. When the phase inversion film is formed on the blank mask for the hard mask, the transparent substrate, the phase inversion film, and the phase inversion film may be selectively selected. An etch stop layer may be formed between the metal layer and the metal layer.

In the binary blank mask and the blank mask for the hard mask, BARC made of an organic material may be selectively formed on the surface of the metal film and the hard mask film after resist development to control scum.

In the step a1), the transparent substrate is a transparent substrate selected from synthetic quartz, calcium fluoride (CaF ₂ ) and fluorine-doped quartz (F-Doped quartz) having a size of 6 inches × 6 inches × 0.25 inch. It is done.

In the step a1), the stress type of the transparent substrate has Tensile Stress and Compressive Stress forms within an effective area of 150 mm ² , the flatness (TIR) is 0.3 um or less, the centerline average roughness is 0.3 nmRa or less, and the birefringence is 2 nm. /6.35mm or less.

In the above steps b1) and e1), the metal film and the hard mask film are formed by a vacuum deposition method, among which DC sputtering, RF sputtering, DC-RF coupled sputtering, ion beam sputtering, ion plating and atomic layer deposition One or more methods selected are possible.

In steps b1) and e1), a metal film and a hard mask film may be formed through DC magnetron reactive sputtering, wherein argon (Ar), helium (He), neon (Ne), and xenon (Xe) are used as inert gases. At least one selected from the group consisting of selected and used, the reactive gas is oxygen (O ₂ ), nitrogen (N ₂ ), carbon monoxide (CO), carbon dioxide (CO ₂ ), nitrogen dioxide (NO ₂ ), nitrogen monoxide (NO ), At least one selected from the group consisting of nitrous oxide (N ₂ O), ammonia (NH ₃ ) and methane (CH ₄ ) can be used.

In steps b1) and e1), the metal layer and the hard mask layer are in an amorphous state to form a vertical pattern during dry etching. The pattern formation method for implementing CD below 65nm, especially below 45nm, is mainly applied by dry etching method, not wet etching method. If the thin film to be etched is crystallized, dry etching is performed. As the thin film is etched in the crystallized direction, it is difficult to form a vertical pattern. Therefore, the metal film is preferably in an amorphous state for forming a vertical pattern.

In the steps b1) and e1), in order to improve the chemical resistance of the metal film and the hard mask film to ozone water, a rapid thermal process (Rapid Thermal Process), in a high vacuum state of 1 × 10 ^-2 torr or less, The vacuum hot plate (Hot-Plate), vacuum plasma (Plsama) and HMDS treatment are selectively performed alone or in combination. Ozone water causes damage to the lower metal film and the hard mask film due to the strong oxidation, and to solve this problem, a method of controlling the concentration of ozone water and controlling the time in the process has been proposed. However, this control method is restricted by different process for each manufacturing company when manufacturing a photomask using a blank mask, and high thin film damage caused by ozone water acts as a factor that degrades the performance of the blank mask. . Therefore, there is a need for a method capable of improving the chemical resistance to the ozone water, which can be solved through chemical stabilization of the thin film through rapid heat treatment, hot plate, plasma treatment. In addition, the above surface treatment method is preferably carried out in a vacuum state, which increases the kinetic energy of the air molecules due to heat irradiation when not in a vacuum state, resulting in contaminants such as oxide film and surface organic matter on the surface. Problems such as scum occur during photoresist development, making it difficult to implement excellent resolution.

In the steps b1) and e1), the composition ratio of the sputtering target for uniformly forming within 150 mm ² , which is an effective area when forming the metal film and the hard mask film, is in the depth direction and the effective area in the effective area of the 95% area of the sputter target. It characterized in that it has a uniform composition ratio of less than 10at%. In general, in the case of a thin film deposited by sputtering, its composition ratio is determined by the sputtering target. In order to form a thin film with an even composition ratio, the composition ratio of the sputtering target should be uniform in the surface area and the depth direction, and through this, the thin film deposition having a uniform composition ratio may be formed evenly on the inorganic material or photoresist formed thereon. Can be. In addition, it can have uniform characteristics in the dry etching, surface treatment and cleaning process by chemicals. Therefore, the sputtering target used for sputtering should be uniform within 10 at% in the depth direction in the effective area within 95% of the target size, and more preferably within 5 at% uniformly to produce excellent blank masks and photomasks. Becomes possible.

In the steps b1) and e1), in order to have a uniform chemical resistance against ozone water for the metal film and the hard mask film, the composition ratio of the thin film is equal to within 5 at% in the depth direction and the effective area in the effective area of 150 mm ² . It is characterized by one. When the metal film and the hard mask film are not equal in the depth direction in the 150 mm ² region, the surface damages of the lower metal film and the hard mask film with respect to ozone water are different. This locally different surface damage forms the surface roughness of the different thin films in the effective area 150 mm ² , and deteriorates optical properties such as transmittance and reflectance. In addition, such different surface damages cause a loading effect according to the degree of damage in the final pattern formation, making it difficult to produce a good photomask. Therefore, the thin film composition ratios of the lower metal film and the hard mask film of the chemically amplified resist should be uniform in the depth direction in the effective region, and in this case, it is preferable to be uniform within 5 at% within the depth direction and 150 mm ² region of each composition ratio. More preferably less than 3 at%.

In the steps b1) and e1), the metal film and the hard mask film are characterized in that the change in transmittance and reflectance after 1 hour immersion in 5 to 100 ppm of ozone water is 2% or less in the exposure wavelength.

In the steps b1) and e1), after the ozone water cleaning of the metal film and the hard mask film, the surface roughness is 0.3 nm Ra or less.

In the steps b1) and e1), the metal film and the hard mask film are characterized in that the uniformity of the surface roughness after washing with ozone water is equal to 0.1 nmRa or less within 150 mm ² , which is an effective area.

In the above steps b1) and e1), the average roughness of the surface center line of the metal film and the hard mask film is 0.1 to 5 nm Ra within 150 mm ² , which is an effective area, and the difference is less than 5 nm Ra. The high surface roughness of the thin film causes diffuse reflection of exposure light and increases the surface energy, thereby causing problems of high reaction rates of particles and chemicals during cleaning. Moreover, different surface roughnesses in the 150 mm ² region make the optical properties different, which makes it difficult to produce good photomasks. Therefore, the surface centerline average roughness of the metal film and the hard mask film should be controlled to be 0.1 to 5 nm Ra or less, and the range in the effective area of 150 mm ² should be controlled to 5 nm Ra or less.

In the steps b1) and e1), the thin film density of the metal film and the hard mask film is 2 to 10 g / cm ³ .

In steps b1) and e1), surface treatment such as a rapid heat treatment apparatus, a hot plate, and a flash lamp is performed to control the substrate dependency of the chemically amplified resist.

In steps b1) and e1), in order to control the substrate dependency of the chemically amplified resist, the concentration of airborne molecular contamination on the surfaces of the metal film and the hard mask film is 100 ppb or less. The chemically amplified resist causes the same problem as the underlying scum due to the lower substrate dependence, which affects the resolution of the final pattern. This is because the strong acid (H ⁺ ), a chemical amplifying agent constituting the chemically amplified resist, This is because neutralizing or binding to an air molecule source containing a basic substance present on the surface of the lower metal film causes the disappearance of the strong acid (H ⁺ ), which is an amplifying agent. Therefore, in order to reduce substrate dependence for excellent pattern formation, the concentration of the surface air molecular source is preferably 100 ppb or less.

In the steps b1) and e1), when the surface treatment of the metal film and the hard mask film is performed using heat treatment, the temperature thereof is 200 to 1000 ° C. In order to improve the chemical resistance of chemical residues and ozone water remaining on the surface during the heat treatment of the metal film, when the surface treatment is carried out below 200 ° C, the chemical residues remaining on the surface can be decomposed. Therefore, the effect is insignificant, and when the temperature is 1000 ° C. or more, the characteristics of the metal film and the hard mask film are changed, making it difficult to use. For example, water remaining on the surface should be heat-treated at 100 ° C or higher, and its decomposition temperature in order to remove impurities such as SO _x and NO _x which act as a factor neutralizing the strong acid (H ⁺ ) of the chemically amplified resist. The above is required. However, when the surface treatment is less than 100 ℃ it is not easy to control the impurity ions, while when the surface treatment at a high temperature of more than 1000 ℃ to give damage such as crystallization of the thin film, reflectance change it is difficult to manufacture a blank mask of excellent characteristics. . Therefore, during the surface treatment of the metal film and the hard mask film, the temperature thereof is preferably advanced at 200 to 1000 ° C, more preferably at 300 to 700 ° C.

In the steps b1) and e1), the reflectance change in the exposure light according to the surface treatment of the metal film and the hard mask film is less than 2% in the 150 mm ² area which is an effective area.

In the steps b1) and e1), the metal film and the hard mask film are characterized in that the contact angle value of the thin film against ultrapure water is within 20 to 50 ° within 150 mm ² , which is an effective area. The contact angle for the thin film can be used as an evaluation means to distinguish the surface hydrophilicity and hydrophobicity. At this time, when the contact angle between the metal film and the hard mask film coated with the organic chemically amplified resist becomes less than 20 °, the adhesion with the chemically amplified resist is degraded. The same problem occurs. On the other hand, forming a contact angle of 50 ° or more acts as a factor to neutralize the strong acid, which is an amplifying agent of the chemically amplified resist, by the formation of organic substances, oxides, and the like, such as adsorption of air molecular contaminants on the surface of the metal film and the hard mask film. Therefore, it is preferable that the contact angle of the thin film with respect to the ultrapure water of a metal film and a hard mask film is 20-50 degrees. In addition, the surface treatment may be performed on the thin film to form such a contact angle.

In steps b1) and e1), in order to control the substrate dependence, the contact angle of the ultrapure order on the surface of the metal film and the hard mask film after stripping the chemically amplified resist is 15 ° to less than 40 °. . On the surface of the metal film and the hard mask film from which the chemically amplified resist has been removed, there should be no scum such as the residue of the chemically amplified resist. Such scum makes etching difficult during dry etching of the lower hard mask layer and the metal layer, resulting in spots and defects. Therefore, the scum such as scum must be controlled, and it can be measured using the contact angle at this time. If the contact angle of the ultrapure water is 40 ° or more, organic matter is present on the surface of the metal film and the hard mask film, which affects defects and resolution such as spots, and when it is less than 15, the contact angle of the lower metal film has changed. It is possible to predict changes in thin film properties. Therefore, it is preferable that the contact angle of the ultrapure water on the surface of the metal film and the hard mask film after the chemically amplified resist removal is 15 ° to less than 40 °.

In steps b1) and e1), the surface flatness after formation of the metal film and the hard mask film is 0.5 um or less within 150 mm ² , which is an effective area. The flatness of the metal film and the hard mask film affects the flatness of the resist film. At this time, when the thickness is 0.5 um or more, the heights of the patterns generated by the flatness are different from each other. Will be different. This causes the loading effect according to the height and height of the pattern when manufacturing the photomask, the CD MTT and CD linearity is changed, it is difficult to form an excellent pattern. Therefore, in order to solve this problem, the flatness within the effective area of 150 mm ² is preferably 0.5 um or less, and even more preferably within 0.3 um.

In step b1), the metal film has a single layer film or a multilayer film structure of two or more layers. The metal film may be formed as a single layer film in order to simplify the process and have excellent defect control ability, and may have a multilayer film structure in which the function of the metal film is detailed. For example, when the metal film is formed of a two-layer film, it may be composed of a light shielding film having a light shielding function with respect to the exposure light and an antireflection film having a reflection function with respect to the exposure light. In order to control the scattering effect of (Scattering Effect), a functional thin film such as a conductive layer (Conductive Layer), a stress reducing film for reducing stress may be additionally formed.

In the step b1), when the metal film is formed as a two-layer film, the light shielding film having a light shielding function is characterized in that the extinction coefficient (k) at the exposure wavelength is 2.5 or more in order to reduce the loading effect. If the extinction coefficient of the light shielding film is 2.5 or less, the thickness of the light shielding film for the function of effectively shielding the exposure light is increased, thereby increasing the loading effect during dry etching. Therefore, in order to reduce such a loading effect, the extinction coefficient k of the light shielding film is preferably 2.5 or more, and more preferably 2.8 or more.

In the step b1), when the metal film is formed of a two-layer film, the anti-reflection film is characterized in that the extinction coefficient (k) at the exposure wavelength is 2.0 or less. When the extinction coefficient (k) of the antireflection film is 2.0 or more, the extinction coefficient of the antireflection film does not generate a large effective difference compared to the light shielding film. The independent function of the film becomes worse, so that the control of the thin film is not easy when the metal film of each two-layer film is improved. In addition, if the anti-reflection film has a high extinction coefficient of 2.0 or more, the metallic properties are relatively high, and thus have a high reflectance at the same thickness as a thin film having an extinction coefficient of 2.0 or less. This causes a problem in that the function of the antireflection film formed for the desired purpose cannot be performed faithfully. Therefore, the extinction coefficient k of the antireflection film is preferably 2.0 or less, more preferably 1.8 or less.

In the step b1), the thickness of the metal film is characterized in that within 200 to 550 Pa in order to reduce the loading effect. If the thickness of the metal film is 200 200 or less, the backscattering effect is increased when the E-beam is exposed, and not only the complicated Optical Proximity Correction (OPC) but also the blurring effect is increased, thereby increasing the CD MTT. And CD uniformity becomes unstable, and when the thickness of the metal film is more than 550 로딩, the loading effect increases during etching due to the relatively thick thickness, causing the CD MTT and CD uniformity to deteriorate. Done. Therefore, in order to solve such a problem, it is preferable that the thickness of a metal film is 200-550 GPa, More preferably, it is 300-500 GPa.

In the step b1), the metal film is essentially one of silicide (Si), molybdenum (Mo), tantalum (Ta), titanium (Ti), tungsten (W), its sole and its oxide, carbide And at least one thin film composed of nitride, oxynitride, oxynitride, or oxynitride.

In the step b1), at least one layer for forming a metal film is characterized in that it comprises a film containing at least oxygen and nitrogen.

In the step b1), the reflectance at the exposure wavelength on the surface of the metal film is 25% or less in the 150 mm ² area which is the effective area.

In the step b1), the change in transmittance and reflectance is effective when the metal film is immersed in Standard Cleaning-1 (SC-1) at 23 ° C., sulfuric acid at 70 ° C. to 90 ° C., and hot-DI water at 70 ° C. to 90 ° C. for 2 hours. It is characterized by less than 1% in the area of 150mm ² .

In step b1), when the metal film is formed, the sputter target material used for forming the metal film may include at least one metal and / or transition metal and silicon.

In the step b1), in the sputter target used for forming the metal film, the composition ratio of the target is 1 to 30 at% of one or more metals and / or transition metals, and 40 to 70 at% of silicon.

In the step b1), the metal film has a transition metal or metal component of 20 to 100 at%, oxygen of 0 to 50 at%, nitrogen of 0 to 50 at%, and carbon of 0 to 50 at%.

In the step b1), it is formed using at least one reactive gas of nitrogen and oxygen to control the reflectivity of the anti-reflection film of the metal film.

In the step b1), the difference in reflectance between the light shielding film and the anti-reflection film of the metal film is characterized in that a difference of more than 10% in the exposure wavelength. When the metal film is composed of two layers and the light shielding film and the antireflection film are formed independently of each other, the reflectance of the antireflection film should be more than 10% different from the reflectance of only the light shielding film. To do this.

In the step b1), the sheet resistance of the metal film is 1 kΩ / □ or less.

In the step e1), the hard mask layer is formed of chromium (Cr), molybdenum (Mo), molybly (MoSi), molybtantalum silicide (MoTaSi), tantalum (Ta), silicon (Si), and tantalum tungsten (TaW). It may be used, and the reactive gas may be used to form oxides, nitrides, carbides, oxynitrides, oxidized carbides, nitride carbides, oxynitrides.

In step e1), the hard mask layer may have a selectivity of 5 or more with the lower metal layer during fluorine-based dry etching.

In the step e1), the hard mask film has a selectivity with respect to the lower metal film during chlorine dry etching, characterized in that 5 or more.

In the step e1), the hard mask film is characterized in that the change in reflectance on the surface of the hard mask film when the removal of the resist film using ozone water is within 2% within 150mm ² , the effective area.

In the step e1), the thickness of the hard mask film is characterized in that less than 50 to 150 Pa.

In the step e1), the sheet resistance of the hard mask film is 1 k 인 / □ or less.

In step d1), the resist coated on the surface of the hard mask layer is characterized in that the chemically amplified resist.

In step d1), the thickness of the resist is characterized in that 1,000 to 2,000Å.

According to the present invention by the above configuration, the blank mask is possible to implement a good resolution by reducing the loading effect, it is possible to manufacture a blank mask having excellent characteristics by controlling the uniformity of the composition ratio of the sputtering target and the thin film. In addition, the blank mask according to the present invention is excellent in chemical resistance to ozone water through the surface treatment, it is possible to manufacture a blank mask having excellent characteristics by controlling the substrate dependency. This makes it possible to manufacture excellent photomasks.

1 is a cross-sectional view of a binary blank mask made by the present invention.
2 is a cross-sectional view of a blank mask for a hard mask film produced according to the present invention.

Examples The present invention will be described in detail by way of examples, but the examples are used only for the purpose of illustrating and explaining the present invention, and are not used to limit the scope of the present invention as defined in the meaning or claims. . Therefore, it will be appreciated that various modifications and equivalent other embodiments may be made from those skilled in the art. Therefore, the true technical protection scope of the present invention will be defined by the technical details of the claims.

(Example 1)

In Example 1, a molybdenum 135mm × 570mm silicide (MoSi = 10: 90at%) target was used as a metal film, and a light shielding film and reflection were made by using a DC magnetron sputtering device on a 6 × 6 × 0.25inch transparent substrate. A protective film was formed. At this time, the composition ratio of the molybdenum silicide target used in the area of 130mm × 545mm, which is the effective area, was analyzed by non-destructive analysis. As a result, Mo was 9.98at% and Si was 90.02at%. Range) was less than 0.3 at%, showing very good results.

Using the target, the light shielding film was formed using only 500 W power, 1.5 mtorr pressure, and argon (Ar) gas. At this time, the thickness of the light shielding film was 360 mm, the optical density was 2.8 at 193 nm, and the reflectance was 54.2% at 193 nm. Thereafter, reactive gas oxygen, carbon, and nitrogen were used, and an antireflection film was formed at 200 W of power and 1.5 mtorr of pressure. Through this, the final thickness of the metal film was 470Å, and the reflectance was 18.23% at 193 nm, showing excellent characteristics. On the other hand, 5 points were selected in the effective area of 150mm ² and the composition ratio of the metal film was analyzed using Auger Electron Spectrometer (AES) equipment as shown in Table 1 below.

location Atomic% Mo Si C O N +125 mm 8.5 59.2 0.36 0.53 31.41 +63 mm 8.6 58.5 0.32 0.62 31.96 0 mm 8.5 58.9 0.35 0.58 31.67 + 63 mm 8.4 59.3 0.38 0.55 31.37 125 mm 8.5 58.5 0.34 0.53 32.13 Mean 8.5 58.88 0.35 0.562 31.708 Range 0.2 0.8 0.06 0.09 0.76

Table 1 shows the results of analyzing the composition ratio of the thin film in the 150 mm ² area, which is an effective area of the prepared metal film. The analyzed position shows the composition ratio along the depth direction with respect to 5 points from the mask center to 0 mm to the +125 mm and -125 mm positions from side to side. As a result of the experiment, the range was 0.06 ~ 0.80 at% and showed very good result in the effective area. Then, using a target having the same size as MoSi on the metal film, a hard mask film was formed to a thickness of 110 kW using oxygen and nitrogen at a power of 300 W, pressure of 1.5 mtorr. In this case, the reflectance on the surface of the hard mask film was 19.3% at 193 nm. Thereafter, heat treatment was performed at 350 ° C. for 30 minutes at 5 × 10 ⁻⁴ torr using vacuum RTP equipment, and the reflectance was measured in the same manner. As a result, 19.6% was shown at 193 nm, and no significant change occurred. In addition, as a result of measuring the contact angle using ultrapure water, the contact angle was 40 ° and it was judged that the adhesion with the superior upper resist film was excellent. And, on the RTP-treated hard mask film, a chemically amplified resist of Fuji's FEP-171 was coated with a thickness of 1500 Å to prepare a blank mask for the hard mask.

After removing the chemically amplified resist by using 40 ppm of ozone water, the measured blank reflectance of the blank mask was measured. It was confirmed that no damage was done to the hard mask. In addition, as a result of measuring the contact angle using ultrapure water on the hard mask film, the contact angle was 23.2 ° and it was confirmed that contaminants such as resist film and organic material were completely removed from the surface. After removing the hard mask film, 40 ppm of ozone water and SC 1 (ammonia: hydrogen peroxide: ultrapure water = 1: 1: 5) were alternately washed for 1 hour in the metal film, followed by 20 minutes using hot-DI at 80 ° C. After washing, the reflectance of the metal film was measured. The average reflectance was 18.92%, and the range was 0.13%.

The present embodiment can be applied not only to the blank mask for hard mask which is the above structure but also to a structure including a phase inversion film. In this case, when the phase shift layer is included, an etch stop layer may be selectively formed on the transparent substrate and the phase shift layer. In addition, the phase inversion film may be formed of a thin film including at least one of oxygen, nitrogen, carbon, and fluorine including MoSi.

(Comparative Example 1)

Comparative Example 1 is a result of evaluating the effect of ozone water according to the composition ratio of the transition metal and the metal component on the metal film surface compared with Example 1 above. For this purpose, a light shielding film and an antireflection film were formed by using a molybdenum silicide (MoSi = 50: 50at%) target as a metal film and using a DC magnetron sputtering device on a 6 × 6 × 0.25inch transparent substrate.

At this time, in forming the light shielding film, the power was deposited using 500 W, the pressure was 1.5 mtorr, and the gas was argon (Ar) gas in the same manner as in Example 1. At this time, the thickness of the light shielding film was 343Å, the optical density was 2.78 at 193 nm, and the reflectance was 58.2% at 193 nm. Thereafter, reactive gas oxygen, carbon, and nitrogen were used, and an antireflection film was formed at 200 W of power and 1.5 mtorr of pressure. Through this, the final thickness of the metal film was 463Å, and the reflectance was 19.73% at 193 nm, showing excellent characteristics. Thereafter, a hard mask film was formed using chromium, and the same RTP surface treatment was performed to coat the photoresist. After removing the photoresist and hard mask film, the reflectance at 193 nm after immersion for 1 hour in 40 ppm ozone water and SC 1 in the metal film was measured. As a result, the reflectance at 193 nm in the metal film was 25.2%, indicating a difference of more than 1%.

(Comparative Example 2)

Comparative Example 2 is a result of evaluating ozone water damage according to the presence or absence of the RTP treatment compared to Comparative Example 1. A blank mask was prepared in the same manner as in Comparative Example 1, and only RTP treatment was not performed on the hard mask film. Accordingly, the reflectance at 193 nm in the metal film was 43%, indicating that the antireflection film was largely damaged.

(Comparative Example 3)

Comparative Example 3 is a result of experiments on the thin film uniformity was carried out using a target that is not uniform in the ratio of the target composition ratio compared to Example 1. At this time, the average composition ratio of MoSi target used was 9.83at% in Mo and 90.17at% in Si, but the composition ratio range in the effective area was 3.2at% in Mo and 6.8at% in Si. After forming the metal film under the same conditions by using this, the composition ratio in the effective area using the AES equipment was analyzed as follows.

Atomic% Mo Si C O N +125 mm 8.9 59.2 0.37 1.33 32.41 +63 mm 11.6 52.3 0.39 3.75 31.96 0 mm 8.5 58.2 0.38 3.25 29.67 63 mm 7.4 61.2 0.40 0.63 30.37 -125mm 12.2 53.5 0.42 2.75 31.13 Mean 9.72 56.88 0.392 2.342 30.67 Range 4.8 8.9 0.05 3.12 2.29

Referring to Table 2, the composition ratio analysis result of the composition ratio of the metal film according to the depth direction with respect to 5 points within 150 mm, which is the effective region, showed a higher change compared to Example 1 with the range of 0.05 to 8.9 at%. Then, after forming the blank mask in the same manner as in Comparative Example 1, the metal film was evaluated for chemical resistance against ozone water and SC 1. As a result, the average change in reflectance at 1.93nm was 1.32% and the range was 3.2%, which was different in each area. This can be seen that the area where ozone water reacts is different due to different composition ratios when the thin film is formed, thereby causing a large range.

(Example 2)

The second embodiment is the result of the experiment for the vertical pattern formation of the blank mask formed by the first embodiment. In the experiment, impurity ions of the hard mask layer were analyzed for substrate dependency control, and cross sections were analyzed using FE-SEM to analyze scum phenomena. At this time, the blank mask manufacturing method was formed in the same manner as in Example 1.

First, Table 3 below shows the results (unit: ppb) of impurity ions on the surface of the hard mask film before the resist film coating when the blank mask is formed in order to analyze the concentration of air molecules on the surface of the hard mask film.

F Cl SOx NOx NH4 Total Impurity concentration 10 8 6 5 9 38

Impurity ions on the hard mask film neutralize the strong acid (H ⁺ ) of the chemically amplified resist coated on the hard mask film, and thus do not develop, resulting in a form of a defect. Therefore, the impurity analysis results showed that the total impurity is 38 ppb, excellent substrate dependence.

Thereafter, in order to analyze the relationship between the impurity ion concentration and Scum, 50-keV E-beam writing was performed, and a Post Exposure Baker was performed at 110 ° C for 10 minutes. Then, the resist film was developed using THMA 2.38% Developer, and then the hard mask film was dry-etched using Cl ₂ , O _2, and He gas. After that, the profile was observed using Hitachi's S-4800 equipment, which is an FE-SEM equipment, and showed excellent results without scum.

(Comparative Example 4)

Comparative Example 4 is a result of an experiment for comparing the scum phenomenon according to the impurity concentration and RTP treatment evaluated in Example 2.

The blank mask was manufactured in the same manner as in Example 2, but impurity ions were applied to the samples without RTP surface treatment and the RTP treated and stored in a blank mask packing box, and then subjected to heat treatment to three samples that had severe surface organic contamination. The analysis was performed as shown in Table 4 below.

F Cl SOx NOx NH4 Total Example 2 10 8 6 5 9 38 No RTP 19 20 19 12 32 102 RTP & Box Packing 14 14 15 9 23 75

Table 4 shows the results of analyzing the impurity ion concentration (unit: ppb) of the hard mask film according to RTP. As a result of the experiment, the total impurity ion amount was 102 ppb when the RTP treatment was not performed, and the ion concentration was about three times higher than when the RTP treatment was performed. After the RTP treatment, the organic pollutants were forcibly adsorbed after being stored in the box and showed 75 ppb, resulting in the adsorption of air pollutants to the surface.

Based on the above results, scums generated after forming a pattern through a lithography process were analyzed in the same manner as in Example 2. As a result, when RTP was not processed, it was confirmed that scum phenomenon such as putting occurred from 70nm CD size. In the case of box storage after RTP treatment, scum phenomenon such as putting did not occur.

As a result, it can be seen that the impurity ion concentration on the surface of the hard mask film should be controlled to 100 ppb or less, and it can be seen that scum control is possible through RTP treatment.

10: transparent substrate
20: light shielding film
30: antireflection film
40: hard mask
100: blank mask produced by the present invention
200: blank mask for hard mask produced by the present invention

Claims (43)

Transparent substrate;
A metal film on the transparent substrate; And
And a resist film formed on the metal film.
And a thin film composition ratio of the metal film is equal to or less than 5 at% in a depth direction and an effective region within a 150 mm ² region, which is an effective region. The method of claim 1,
A blank mask, wherein a phase inversion film or an etch stop film is selectively formed between the transparent substrate and the metal film. The method of claim 2,
A blank mask, characterized in that the composition ratio of the metal or transition metal is 5 to 15 at% in order to have excellent chemical resistance to ozone water in the composition ratio of the phase inversion film. The method of claim 1,
A blank mask, wherein the metal film is in an amorphous state. The method of claim 1,
A blank mask, wherein the metal film has a single layer film or a multilayer film structure of two or more layers. The method of claim 1,
A blank mask, wherein when the metal film is composed of a light shielding film and an antireflection film, the light shielding film having a light shielding function has a extinction coefficient k at an exposure wavelength of 2.5 or more in order to reduce a loading effect. The method of claim 1,
When the metal film is composed of a light shielding film and an antireflection film, the antireflection film has a extinction coefficient k at an exposure wavelength of 2.0 or less. The method of claim 1,
The thickness of the metal film is a blank mask, characterized in that within 200 to 550 kPa to reduce the loading effect. The method of claim 1,
The metal film includes essentially one of silicide (Si), molybdenum (Mo), tantalum (Ta), titanium (Ti), and tungsten (W), and the sole and its oxides, carbides, nitrides, carbides, A blank mask comprising at least one thin film composed of oxynitride or oxynitride. The method of claim 1,
A blank mask, characterized in that at least one layer forming the metal film comprises a film containing at least oxygen and nitrogen. The method of claim 1,
A blank mask, characterized in that the reflectance at the exposure wavelength on the surface of the metal film is 25% or less in the 150 mm ² area, which is the effective area. The method of claim 1,
The metal film is within 150mm ² where the transmittance and reflectance change are effective when immersed in 23 ° C Standard Cleaning-1 (SC-1), 70 ° C to 90 ° C sulfuric acid, and 70 ° C to 90 ° C hot-DI water for 2 hours. A blank mask, which is% or less. The method of claim 1,
The blank mask characterized by the change of the transmittance | permeability and reflectance after immersion of a metal film in 5-100 ppm of ozone water at 23 degreeC for 2 hours in exposure wavelength. The method of claim 1,
A blank mask, wherein the concentration of surface impurity ions of the metal film is 100 ppb or less. The method of claim 1,
The metal film is a blank mask, characterized in that the contact angle (Contact Angle) value of the thin film with respect to ultrapure water is within 20 to 50 ° within 150mm ² which is an effective area. The method of claim 1,
The metal film is a blank mask, characterized in that the contact angle to the ultrapure order on the surface of the metal film after stripping the chemically amplified resist is less than 15 ° to 40 °. The method of claim 1,
A blank mask, wherein the sputter target used for forming a metal film has a composition ratio of 1 to 30 at% of at least one metal and / or transition metal and 40 to 70 at% of silicon. The method of claim 1,
The metal film is a blank mask, characterized in that the transition metal or metal component is 20 to 100 at%, oxygen is 0 to 50 at%, nitrogen is 0 to 50 at%, carbon is 0 to 50 at%. The method of claim 1,
A blank mask, wherein the metal film has a uniform surface roughness after washing with ozone water equal to or less than 0.1 nm Ra within 150 mm ² , which is an effective area. The method of claim 1,
A blank mask, wherein the surface center line average roughness of the metal film is 0.1 to 5 nm Ra within 150 mm ² , which is an effective area, and a difference thereof is 5 nm Ra or less. Transparent substrate;
A metal film on the transparent substrate; And
And a resist film formed on the metal film.
In order to reduce chemical resistance and substrate dependence on ozone water, the metal film is subjected to a rapid thermal process, a vacuum hot plate, and a vacuum plasma under a high vacuum of 1 × 10 ^-2 torr or less under high vacuum. Blank mask characterized in that processes such as (Plsama) and HMDS treatment are optionally performed singly or in combination. The method of claim 21,
Blank mask, characterized in that the surface treatment is carried out at a temperature of 200 to 1000 ℃ when using a heat treatment. The method of claim 21,
A blank mask characterized in that the change in reflectance of the exposure light due to the surface treatment of the metal film is less than 2% in the 150 mm ² area, which is an effective area. The method of claim 21,
A blank mask characterized in that the contact angle value of the thin film against ultrapure water is within 30 to 45 ° within an effective area of 150 mm ² by metal film surface treatment. Transparent substrate;
A metal film on the transparent substrate;
A hard mask layer on the metal layer; And
And a resist film formed on the hard mask film.
And the thin film composition ratio of the hard mask film is equal to the effective area within a depth of 150 mm ² and within 5 at% within the effective area. The method of claim 25,
A blank mask, characterized in that a phase inversion film is formed between the transparent substrate and the metal film. The method of claim 25,
A blank mask, wherein the hard mask film is in an amorphous state. The method of claim 25,
The blank mask characterized by the change of the transmittance | permeability and reflectance after immersion of a hard mask film in 5-100 ppm of ozone water at 23 degreeC for 1 hour in an exposure wavelength. The method of claim 25,
A blank mask, wherein the concentration of surface impurity ions of the hard mask film is 100 ppb or less. The method of claim 25,
The hard mask layer may be made of chromium (Cr), molybdenum (Mo), molybly (MoSi), molybtantalum silicide (MoTaSi), tantalum (Ta), silicon (Si), and tantalum tungsten (TaW). And a reactive mask to form oxides, nitrides, carbides, oxynitrides, oxidized carbides, nitrides, oxynitrides. The method of claim 25,
The hard mask film is a blank mask, characterized in that the contact angle with respect to the ultrapure order on the surface of the metal film after the stripping of the chemically amplified resist (15) to less than 40 °. The method of claim 25,
The hard mask film is a blank mask, characterized in that the selectivity with respect to the lower metal film 5 or more during the fluorine-based dry etching. The method of claim 25,
The hard mask film is a blank mask, characterized in that the change in reflectance on the surface of the hard mask film within 2% within the effective area 150mm ² when removing the resist film using ozone water. The method of claim 25,
The hard mask film is a blank mask, characterized in that the surface impurity ion concentration remaining on the surface of the hard mask film when removing the resist film using ozone water is 100 ppb or less. The method of claim 25,
A blank mask, wherein the hard mask film has a thickness of 50 to 150 GPa or less. The method of claim 25,
A blank mask characterized in that the sheet resistance of the hard mask film is 1 kΩ / □ or less. The method of claim 25,
The hard mask film is a blank mask, characterized in that the uniformity of the surface roughness after washing with ozone water is equal to 0.1 nm Ra or less within 150 mm ² , which is an effective area. The method of claim 25,
A blank mask, wherein the average surface roughness of the surface center line of the hard mask film is 0.1 to 5 nm Ra within 150 mm ² , which is an effective area, and a difference thereof is 5 nm Ra or less. Transparent substrate;
A metal film on the transparent substrate;
A hard mask film formed on the metal film; And
And a resist film formed on the hard mask film.
In order to reduce chemical resistance and substrate dependence on ozone water, the hard mask film is treated with a rapid thermal process, a vacuum hot plate, and a vacuum in a high vacuum of 1 × 10 ^-2 torr or less. A blank mask characterized in that processes such as plasma (Plsama) and HMDS treatment are optionally performed singly or in combination. 40. The method of claim 39,
Blank mask, characterized in that the surface treatment is carried out at a temperature of 200 to 1000 ℃ when using a heat treatment. 40. The method of claim 39,
A blank mask characterized in that the change in reflectance of the exposure light according to the hard mask film surface treatment is less than 2% in the 150 mm ² area, which is an effective area. The method of claim 39,
A blank mask characterized in that the contact angle value of the thin film against ultrapure water is within a range of 30 to 45 ° within an effective area of 150 mm ² by hard mask film surface treatment. Transparent substrate;
A metal film on the transparent substrate;
A hard mask film formed on the metal film; And
And a resist film formed on the hard mask film.
The composition ratio of the sputtering target for forming the metal film and the hard mask film has a uniform composition ratio in which the ratio of the composition ratio in the effective direction of the 95% region of the sputter target and the composition ratio in the effective region is 10 at% or less. The blank mask manufactured using the sputtering target for blank masks mentioned above.

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