KR102400198B1 - Photomask blank, photomask and method of fabricating a semiconductor device - Google Patents

Abstract

An embodiment relates to a photomask blank, a photomask, a manufacturing method of a semiconductor device, etc. and provides a photomask blank, etc. comprising: a light-transmitting substrate; and a multi-layered light-blocking film disposed on the light-transmitting substrate. The light-blocking film includes a first light-blocking layer having a first Young's modulus; and a second light-blocking layer having a second Young's modulus. The first light-blocking layer is disposed closer to the light-transmitting substrate than the second light-blocking layer, and the first Young's modulus is greater than the second Young's modulus. The photomask blank, the photomask, etc. of the embodiment have improved defect resistance, and the manufacturing method of a semiconductor device provides a manufacturing method with high precision and less occurrence of defects.

Description

Manufacturing method of photomask blank, photomask and semiconductor device

One embodiment relates to a photomask blank, a photomask having improved performance. Another embodiment relates to a method of manufacturing a semiconductor device in which the occurrence of defects is reduced with high precision.

BACKGROUND ART Due to high integration of semiconductor devices and the like, miniaturization of circuit patterns of semiconductor devices is required. For this reason, the importance of a lithography technique, which is a technique for developing a circuit pattern on a wafer surface using a photomask, is further emphasized.

In order to develop a miniaturized circuit pattern, a shorter wavelength of an exposure light source used in an exposure process is required. Recently used exposure light sources include ArF excimer lasers (wavelength 193 nm) and the like.

On the other hand, the photomask includes a binary mask, a phase shift mask, and the like.

The binary mask has a structure in which a light-blocking layer pattern is formed on a light-transmitting substrate. In the binary mask, the pattern is exposed on the resist film on the wafer surface by transmitting the light-shielding portion including the light-shielding layer and blocking the exposure light. However, in the binary mask, as the pattern becomes finer, a problem may occur in the fine pattern phenomenon due to diffraction of light generated at the edge of the transmission part in the exposure process.

The phase shift mask includes a Levenson type, an outrigger type, and a half-tone type. Among them, the halftone phase shift mask has a configuration in which a pattern formed of a semi-transmissive film is formed on a light-transmitting substrate. In the halftone phase shift mask, the transmissive part not including the transflective layer transmits exposure light, and the transflective part including the transflective layer transmits attenuated exposure light. The attenuated exposure light has a phase difference compared with the exposure light passing through the transmission part. Due to this, the diffracted light generated at the edge of the transmissive part is canceled by the exposure light that has passed through the transflective part, so that the phase shift mask can form a finer fine pattern on the wafer surface.

Domestic Patent Publication No. 10-2012-0121333 Domestic Registered Patent No. 10-1308838

SUMMARY One embodiment provides a photomask blank, and a photomask having improved performance. Another embodiment provides a method of manufacturing a semiconductor device in which the occurrence of defects is reduced with high precision.

In order to achieve the above object, a photomask blank according to an embodiment includes a light-transmitting substrate; and a multi-layered light-shielding film disposed on the light-transmitting substrate.

The light blocking layer may include a first light blocking layer having a first Young's modulus; and a second light blocking layer having a second Young's modulus. The first light blocking layer may be disposed closer to the light-transmitting substrate than the second light blocking layer.

The first Young's modulus may be greater than the second Young's modulus.

The second Young's modulus may be 0.15 to 0.55 times the first Young's modulus.

The second Young's modulus may be 1.0 to 4.2 kPa.

The second light blocking layer may have a hardness of 0.55 kPa or less.

A photomask blank according to another embodiment includes a light-transmitting substrate; and a multi-layered light-shielding film disposed on the light-transmitting substrate, wherein the light-shielding film includes: a first light-blocking layer having a first Young's modulus; and a second light blocking layer disposed on the first light blocking layer and having a second Young's modulus.

The second Young's modulus may be 1.0 kPa or more.

The thickness of the second light blocking layer may be 30 nm or more.

The second light blocking layer may have a value such that a standard deviation of the adhesive force measured at 16 different positions is 8% or less of the average of the adhesive force.

The second light blocking layer may have a value in which a standard deviation of the separation force measured at 16 different positions is 5% or less of the average separation force.

A photomask blank according to another embodiment includes a light-transmitting substrate; and a multi-layered light-shielding film disposed on the light-transmitting substrate, wherein the light-shielding film includes: a first light-blocking layer having a first Young's modulus; and a second light blocking layer disposed on the first light blocking layer and having a second Young's modulus. The first light blocking layer may be disposed closer to the light-transmitting substrate than the second light blocking layer.

The first Young's modulus may be greater than the second Young's modulus.

The second Young's modulus may be 0.15 to 0.55 times the first Young's modulus.

The second Young's modulus may be 1.0 to 4.2 kPa.

The second light blocking layer may have a hardness of 0.55 kPa or less.

A photomask blank according to another embodiment includes a light-transmitting substrate; and a multilayer patterned light blocking film disposed on the light-transmitting substrate, wherein the patterned light blocking film includes: a patterned first light blocking layer having a first Young's modulus; and a patterned second light blocking layer disposed on the first light blocking layer and having a second Young's modulus.

The first Young's modulus may be greater than the second Young's modulus.

The second Young's modulus may be 1.0 kPa or more.

The second Young's modulus may be 0.15 to 0.55 times the first Young's modulus.

The second Young's modulus may be 1.0 to 4.2 kPa.

The second light blocking layer may have a hardness of 0.55 kPa or less.

A method of manufacturing a semiconductor device according to another embodiment includes a preparation step of preparing a target substrate; And a patterning step of manufacturing a patterned target substrate by applying a photomask on one surface of the target substrate and patterning; manufacturing semiconductor devices, including

The photomask described above is applied to the photomask.

The photomask blank of the embodiment may provide a photomask blank capable of reducing the degree of defects due to particles while maintaining other performances equal to or higher by applying a light-shielding film having a controlled Young's modulus.

The photomask of another embodiment may provide a photomask capable of reducing defects caused by particles and obtaining a more improved light blocking effect even when a pattern with a finer line width is applied.

In another embodiment of the method of manufacturing a semiconductor device, a semiconductor device having fewer defects may be manufactured by using the above-mentioned photomask.

1 is a conceptual diagram illustrating a cross-section of a structure of a photomask blank according to an embodiment;
2 is a conceptual diagram illustrating a cross-section of the structure of a photomask according to an embodiment.
3 is a conceptual diagram illustrating a cross-section of the structure of a photomask blank according to another embodiment.
4 is a conceptual diagram illustrating a cross-sectional view of the structure of a photomask according to another embodiment.
5 is an enlarged conceptual view of A of FIG. 2 ;
6A and 6B are enlarged conceptual views of a portion A of FIG. 6A related to a cross section and particle formation of a comparative example.
7a and 7b are photographs showing an example of forming scratchable particles in Comparative Example 1 and Comparative Example 2 of laboratory examples, respectively (results after applying HF filter to the tester).

Hereinafter, the embodiments will be described in detail so that those of ordinary skill in the art can easily implement them. However, the embodiment may be implemented in various different forms and is not limited to the embodiment described herein.

As used herein, the terms "about," "substantially," and the like, are used in a sense at or close to the numerical value when the manufacturing and material tolerances inherent in the stated meaning are presented, and to aid understanding of embodiments. It is used to prevent an unconscionable infringer from using the mentioned disclosure in an unreasonable way.

Throughout this specification, the term "combination of these" included in the expression of the Markush form means one or more mixtures or combinations selected from the group consisting of the components described in the expression of the Markush form, and the components It is meant to include one or more selected from the group consisting of.

Throughout this specification, reference to “A and/or B” means “A, B, or A and B”.

Throughout this specification, terms such as “first”, “second” or “A” and “B” are used to distinguish the same terms from each other unless otherwise specified.

In this specification, the meaning that B is located on A means that B is located on A or B is located on A while another layer is located in between, and B is located in contact with the surface of A It is not construed as being limited to

In the present specification, unless otherwise specified, the expression “a” is interpreted as meaning including “a” or “plural” as interpreted in context.

The drawings attached to this specification may be exaggerated for the purpose of properly explaining the concept of the embodiment, and the embodiment is not limited by the drawings and interpreted.

In the present specification, the exposure wavelength is described as a 193 nm ArF wavelength, but unless otherwise specified, the scope of the embodiments is not construed as being limited to being applied to the wavelength.

As semiconductor devices are highly integrated, it is required to form a finer circuit pattern on a semiconductor substrate. As the line width of a pattern developed on a semiconductor substrate is further refined, stricter control of defects caused by particles is required.

It is essential that a photomask applied as a mask for forming a semiconductor device pattern has excellent resolution. Unlike a photomask for a display, it is considered that stricter conditions are required for a resolution or defect, in particular, in a photomask for a semiconductor to which a pattern is applied with an enlarged pattern. Ideally, the upper edge of the pattern (indicated by A in FIGS. 2 and 5, etc.) in the cross section is ideally formed at a substantially right angle, but in reality, it is not easy to be completely formed at a right angle. In particular, during the etching process of the photomask, particles originating from corners, etc. may be formed, and these particles may act as scratchable particles of the photomask. That is, the particles may damage the substrate or pattern during etching, cleaning, etc., which in turn may lead to defects in the pattern of the photomask and the semiconductor pattern manufactured therefrom. The inventors confirm that it is possible to substantially suppress the generation of particles by forming the light-shielding film of the photomask in a structure of two or more layers, and controlling properties such as Young's modulus and hardness between each layer, and present exemplary embodiments.

1 and 3 are conceptual views illustrating the structure of a photomask blank according to one embodiment and another embodiment, respectively, in cross section, and FIGS. 2 and 4 are respectively one embodiment and a photomask according to another embodiment. It is a conceptual diagram explaining the structure in cross section. 5 is an enlarged conceptual view of A of FIG. 2 . Hereinafter, embodiments will be described in more detail with reference to FIGS. 1 to 5 .

Photomask blank (100) and photomask (300)

In order to achieve the above object, a photomask blank 100 according to an embodiment of the embodiment includes a light-transmitting substrate 10; and a multi-layered light blocking film 30 disposed on the light-transmitting substrate.

The light blocking layer 30 includes a first light blocking layer 301 having a first Young's modulus; and a second light blocking layer 302 having a second Young's modulus.

The first light blocking layer 301 is disposed closer to the light-transmitting substrate 10 than the second light blocking layer.

The photomask blank 100 includes a light-transmitting substrate 10; In addition, a phase shift film 20 disposed between the light blocking film 30 may be further included.

The photomask blank 100 may further include a hard coating layer (not shown) disposed on the light blocking film 30 .

The photomask blank 100 may further include a hard coating layer (not shown) positioned on the light blocking layer 30 and a photoresist layer (not shown) positioned on the hard coating layer.

In order to achieve the above object, the photomask 300 according to an embodiment of the embodiment includes a light-transmitting substrate 10; and a multilayer patterned light blocking film 33 disposed on the light-transmitting substrate.

The patterned light blocking layer 33 may include a patterned first light blocking layer 331 having a first Young's modulus; and a patterned second light blocking layer 332 having a second Young's modulus.

The patterned first light blocking layer 331 is disposed closer to the light-transmitting substrate 10 than the patterned second light blocking layer 332 .

The photomask 300 includes a light-transmitting substrate 10; In addition, a patterned phase shift film 23 disposed between the patterned light blocking film 33 may be further included.

The photomask 300 may further include a hard coating layer (not shown) disposed on the patterned light blocking layer 33 . The hard coating layer is also called a hard mask layer, and may be patterned.

The patterned light blocking layer and the patterned phase shift layer may be formed by patterning the light blocking layer and the phase shift layer of the photomask blank, respectively.

Light blocking film 30 and patterned light blocking film 33

In an embodiment, the light blocking film 30 may be located on the top side of the light-transmitting substrate 10 . The light blocking film 30 has a characteristic of blocking at least a certain portion of the exposure light incident from the bottom side of the light-transmitting substrate 10 . In addition, when the phase shift film 20 or the like is positioned between the light transmissive substrate 10 and the light blocking film 30 , the light blocking film 30 is phase reversed in the process of etching the phase shift film 20 and the like in a pattern shape. It has etching characteristics to be distinguished from neighboring films such as a film, and thus serves as an etching mask.

In the embodiment, the light blocking film 30 includes a patterned first light blocking layer 331 ; and a patterned second light blocking layer 332 .

Hereinafter, unless otherwise specified, the description of the patterned light-shielding film, the patterned first light-blocking layer, the patterned second light-shielding layer, and the like is applied to the description of the light-shielding film, the first light-blocking layer, the second light-blocking layer, and the like.

The first light blocking layer 301 may have a first Young's modulus.

The second light blocking layer 302 may have a second Young's modulus.

The first Young's modulus may be greater than the second Young's modulus.

The second light blocking layer is located on the light blocking film. The first light blocking layer is located under the light blocking film. In this case, the Young's modulus of the second light blocking layer may be smaller than the Young's modulus of the first light blocking layer.

The second light-blocking layer is located on a side farther from the light-transmitting substrate. In this case, the farther from the light-transmitting substrate means that the relative position of the second light-blocking layer with respect to the first light-blocking layer is farther than that of the light-transmitting substrate. In this case, the Young's modulus of the second light blocking layer may be smaller than the Young's modulus of the first light blocking layer.

By making the Young's modulus of the second light-shielding layer smaller than the Young's modulus of the first light-shielding layer, the frequency of occurrence of particles that may occur due to partial loss of the light-shielding layer can be reduced, and the possibility of occurrence of scratches caused by particles can also be significantly reduced. . In addition, since the size of the generated particles is also formed smaller than that of a single-layer light blocking film, the generation of scratchable particles can be further suppressed (refer to FIGS. 5, 6A, and 6B.)

The second Young's modulus may be 0.15 to 0.55 times the first Young's modulus. The second Young's modulus may be 0.20 to 0.45 times the first Young's modulus. The second Young's modulus may be 0.23 to 0.42 times the first Young's modulus.

When the second Young's modulus is less than 0.15 times the first Young's modulus, the etching rate may be slow in etching using an etchant such as a chlorine-based gas. When the second Young's modulus is greater than 0.55 times the first Young's modulus, the effect of reducing particle generation may be insignificant. When the second Young's modulus is 0.2 to 0.45 times the first Young's modulus, it is possible to sufficiently obtain the effect of reducing the possibility of damage due to the generation of particles while minimizing the degradation of the etching characteristics in the etching using an etchant such as a chlorine-based etching gas.

The second Young's modulus may be 1.0 kPa or more. The second Young's modulus may be 1.0 to 4.2 kPa. The second Young's modulus may be 1.2 to 3.7 kPa. The second Young's modulus may be 2.3 to 3.5 kPa. In this range, the first light blocking layer may appropriately induce the effect of suppressing the generation of particles while having an appropriate etching characteristic as a whole of the light blocking layer.

The first Young's modulus may be 7 to 13 kPa. The first Young's modulus may be 7.3 to 12 kPa. The first Young's modulus may be 8 to 11.8 kPa. In the case of having such a first Young's modulus range, the entire light-shielding film may have appropriate transmittance, optical density, and etching characteristics, and may be particularly suitable for application of a light source having a wavelength of 193 nm.

The first light blocking layer 301 may have a first hardness.

The second light blocking layer 302 may have a second hardness.

The first hardness may be greater than the second hardness.

The second light blocking layer is located on the light blocking film. The first light blocking layer is located under the light blocking film. In this case, the hardness of the second light blocking layer may be smaller than the hardness of the first light blocking layer.

The second light-blocking layer is located on a side farther from the light-transmitting substrate. In this case, the farther from the light-transmitting substrate means that the relative position of the second light-blocking layer with respect to the first light-blocking layer is farther than that of the light-transmitting substrate. In this case, the hardness of the second light blocking layer may be smaller than the hardness of the first light blocking layer.

By making the hardness of the second light-shielding layer to have a value smaller than that of the first light-shielding layer, the frequency of occurrence of particles that may occur due to partial loss of the light-shielding film can be reduced, and the possibility of occurrence of scratches caused by particles can also be significantly reduced. . In addition, since the size of the generated particles is also formed smaller than that of a single-layer light blocking film, the generation of scratchable particles can be further suppressed (refer to FIGS. 5, 6A, and 6B.)

The second hardness may be 0.15 to 0.55 times the first hardness. The second hardness may be 0.2 to 0.4 times the first hardness. When the second hardness is less than 0.15 times the first hardness, the etch rate may be slow in etching using an etchant such as a chlorine-based gas. When the second hardness is greater than 0.55 times the first hardness, the effect of reducing the possibility of damage by particles may be insignificant. When the second hardness is 0.2 to 0.4 times the first hardness, it is possible to sufficiently obtain the effect of reducing the possibility of damage by particles while minimizing the possibility of deterioration of the etching characteristics of the light-shielding film due to the increase in optical density.

The second hardness may be 0.55 kPa or less. The second hardness may be 0.3 to 0.55 kPa. The second hardness may be 0.42 to 0.52 kPa. The second hardness may be 0.45 to 0.51 kPa. In this range, the first light-shielding layer may appropriately induce the effect of suppressing the occurrence of scratches by particles while having appropriate optical properties as a whole of the light-shielding film.

The first hardness may be 1 to 3 kPa. The first hardness may be 1.1 to 2.5 kPa. The first hardness may be 1.3 to 2.5 kPa. In the case of having such a first hardness range, the light shielding film may have appropriate transmittance, optical density, and etching characteristics as a whole, and may be particularly suitable for application of a light source having a wavelength of 193 nm.

The Young's modulus and the hardness can be measured by AFM. Specifically, using Park System's AFM equipment (equipment model XE-150), the scan rate is 0.5Hz, and contact mode, cantilever model Park System's PPP-CONTSCR is applied to measure. Measure the adhesive force at 16 points within the measurement target, take the average value, and use the hardness or Young's modulus value obtained therefrom as the above hardness or Young's modulus value. For the measuring tip applied during measurement, a Berkovich tip made of silicon (Poisson's ratio of tip: 0.07) is applied, and the results of hardness and Young's modulus measurement are applied by Oliver and Pharr Model. present.

By the above measurement, separation force, adhesion force, and the like are also obtained. Separation force and/or adhesion force measured at 16 different positions have a small deviation in the measured values as a whole, which means that the physical properties of the light-shielding film are uniform throughout the measurement positions.

The standard deviation of the adhesion energy measured at 16 different positions of the second light blocking layer 302 (each position is preferably applied at least 1 cm apart from each other) is the average of the adhesion force. may be 8% or less, may be 6% or less, or may be 5% or less. The standard deviation may be 0.001% or more of the average of the adhesive force. The photomask blank 100 or the photomask 300 having these characteristics may have the effect of suppressing particle formation evenly and reducing scratch formation caused by particles even when a fine pattern is formed as a whole.

The adhesive force of the second light blocking layer 302 may be 0.25 fJ or more. The adhesive force of the second light blocking layer 302 may be 0.30 fJ or more. The adhesive force of the second light blocking layer 302 may be 0.4 fJ or less.

The adhesive force of the second light blocking layer 302 may be greater than that of the first light blocking layer 301 by 0.10 fJ or more. The adhesive force of the second light blocking layer 302 may be greater than that of the first light blocking layer 301 by 0.15 fJ or less.

The standard deviation of the pull-off force measured at 16 different positions of the second light blocking layer 302 may be 5% or less, 3% or less, or 2% or less of the average of the separation force. The standard deviation may be 0.001% or more of the average separation force. The photomask blank 100 or photomask 300 having these characteristics can have the effect of suppressing particle formation evenly and reducing scratch formation caused by particles even when a fine pattern is formed as a whole.

The separation force of the second light blocking layer 302 may be 4.0 nN or more. The separation force of the second light blocking layer 302 may be 4.1 nN or more. The separation force of the second light blocking layer 302 may be 4.8 nN or less.

The separation force of the second light blocking layer 302 may be greater than that of the first light blocking layer 301 by 0.6 nN or more. The separation force of the second light blocking layer 302 may be 1.2 nN or less greater than the adhesion force of the first light blocking layer 301 .

The first light blocking layer 301 and the second light blocking layer 302 may have a thickness ratio of 1:0.02 to 0.25. The first light blocking layer 301 and the second light blocking layer 302 may have a thickness ratio of 1:0.04 to 0.18. The light blocking film 30 including both the first light blocking layer and the second light blocking layer may have particle generation and scratch reduction characteristics from above while satisfying conditions such as transmittance and optical density.

The second light blocking layer 302 may have a thickness of 30 to 80 nm. The second light blocking layer 302 may have a thickness of 40 to 70 nm. When the second light blocking layer is formed with such a thickness, the effect of reducing particle formation may be more excellent.

The thickness or thickness ratio can be confirmed by layer division, etc. confirmed by a micrograph of a cross section, and any method that can confirm the thickness can be applied without limitation.

The light blocking layer 30 may have a transmittance of 1 or more for a wavelength of 193 nm, or 1.33 or more. The light blocking layer 30 may have a transmittance of 1.38 or more for a wavelength of 193 nm, or 1.4 or more. The light blocking layer 30 may have a transmittance of 1.6 or less for a wavelength of 193 nm.

The light blocking film 30 may have an optical density of 2.0 or less for a wavelength of 193 nm, or 1.87 or less. The light blocking layer 30 may have an optical density of 1.8 or more for a wavelength of 193 nm, or 1.83 or more.

The optical density of the laminate including the light blocking film 30 and the phase shift film 20 may be 3.0 or more.

When the light-shielding film has such transmittance and optical density, it is possible to impart an intended excellent light-shielding effect to the photomask or photomask blank.

The first light blocking layer 301 and the second light blocking layer 302 each contain a metal element in each layer.

A transition metal may be applied as the metal, and the transition metal may include any one selected from the group consisting of Cr, Ta, Ti and Hf. More specifically, the first light blocking layer 30 and/or the second light blocking layer 30 may contain chromium.

The metal included in the first light blocking layer 301 or the second light blocking layer 302 provides light blocking properties by its content and at the same time affects physical properties such as hardness. However, the physical properties may be different depending on various factors, such as the density of the light-shielding layer, the degree of crystallization of elements included in the light-shielding layer, the content of non-metal elements in the light-shielding layer, and arrangement of each constituent element in the light-shielding layer.

The second light blocking layer 302 may have a higher metal content than the first light blocking layer 301 . However, it is difficult to control the overall physical properties by simply increasing the metal content because the overall optical properties and etching properties required by the photomask must also be satisfied rather than limitedly controlling the hardness properties and Young's modulus properties.

The difference in physical properties such as hardness between the second light blocking layer 302 and the first light blocking layer 301 is the content ratio of the inert gas applied in the sputtering process for deposition, the content of the above-mentioned metal, and the first light blocking layer. and the ratio of the reactive gas applied to the formation of the second light blocking layer and the like. Specific details will be described later.

Other thin films

As mentioned above, a phase shift film, a hard mask film, a photoresist film, etc. can be applied to the photomask blank or the photomask.

In the photomask blank 100 , a light-transmitting substrate 10 , a phase shift film 20 , a light blocking film 30 , a photoresist film (not shown), etc. may be sequentially stacked, and between the light blocking film and the photoresist film A hard mask layer (not shown) may be further disposed on the .

The phase shift film 20 may be positioned between the light-transmitting substrate 10 and the light blocking film 30 . The phase shift layer 20 attenuates the light intensity of the exposure light passing through the phase shift layer 20 and controls the phase difference to substantially suppress the diffracted light generated at the edge of the transfer pattern.

The transmittance of the light-transmitting substrate 10 with respect to the exposure light having a wavelength of 193 nm may be 85% or more. The transmittance may be 87% or more. The transmittance may be 99.99% or less. For example, a synthetic quartz substrate may be applied to the light-transmitting substrate 10 . In this case, the light-transmitting substrate 10 may suppress attenuation of light passing through the light-transmitting substrate 10 . However, the material of the light-transmitting substrate 10 is not limited as long as it has light transmittance with respect to exposure light and can be applied to the photomask 300 .

The phase shift film 20 may have a phase difference of 170 to 190° with respect to light having a wavelength of 193 nm. The phase shift film 20 may have a phase difference of 175 to 185° with respect to light having a wavelength of 193 nm. The phase shift film 20 may have a transmittance of 3 to 10% for light having a wavelength of 193 nm. The phase shift film 20 may have a transmittance of 4 to 8% for light having a wavelength of 193 nm. In this case, the resolution of the photomask 300 including the phase shift film 20 may be improved.

The phase shift layer 20 may include a transition metal and silicon. The phase shift layer 20 may include a transition metal, silicon, oxygen, and nitrogen. The transition metal may be molybdenum.

For the description of the patterned phase shift film 23, the above description of the phase shift film 20 is applied as it is.

A hard mask (not shown) may serve to suppress a pattern collapse phenomenon in which the photoresist film collapses during pattern etching. In addition, in the patterning process of the light-shielding film 30, it can also function as an etching mask film.

The hard mask may include silicon, and any one selected from nitrogen and oxygen. Illustratively, the hard mask may be SiON, SiN, etc., but is not limited thereto.

Utilization and Manufacturing

The photomask 300 is patterned according to the desired design of the photomask blank 100 , and the patterning process is performed through at least several etching and cleaning processes. Illustratively, a desired pattern is formed on the photoresist film through exposure and development, and a hard mask film is exposed through selective etching. Thereafter, an etchant having a relatively large selectivity is used for the hard mask layer and the light blocking layer to remove a predetermined portion according to the design of the hard mask layer and the light blocking layer. At this time, by changing the etchant, the phase shift film may also be removed. Thereafter, part or all of the hard mask layer and the light blocking layer are removed as needed, and an etchant is also applied during the removal process. The etchant is selectively applied according to the characteristics of each film, and in the case of dry etching, a fluorine-based etchant, a chlorine-based etchant, etc. may be selectively used by mixing with a reactive gas (oxygen, etc.) or an inert gas (nitrogen, helium, etc.). In addition, in each etching step, a cleaning process may be performed for the purpose of removing the etchant and confirming whether the etching degree is appropriate. In this process, the part where the density of the film is not constant is unintentional due to external impact (eg, physical impact by the cleaning solution, etc.) or chemical damage by the etchant, or their interaction due to the cleaning solution or the film density. Foreign substances may occur in the form of particles, which may also cause scratchy defects.

The photomask blank and/or photomask of the embodiment is developed and cleaned by controlling the physical properties of the two layers disposed above and below each other while forming the light-shielding film itself as a multi-layer, or by controlling the hardness and/or Young's modulus of the light-shielding film located thereon It is possible to reduce the generation of foreign substances such as particles in the process of such as, and even if particles are generated, it is possible to reduce the scratch defects caused by this. In addition, these characteristics are advantages that can be obtained while maintaining the optical characteristics, thickness characteristics, etching characteristics, etc. of the light-shielding film at a certain level or more.

Hereinafter, a method for manufacturing the light-shielding film will be described.

A method of manufacturing a light-shielding film includes a preparation step of installing a substrate and a sputtering target in a sputtering chamber; a film forming step of injecting an atmospheric gas into the sputtering chamber and applying electric power to the sputtering target to form a light-shielding film on the substrate; a heat treatment step of heat-treating the formed light-shielding film to control and stabilize residual stress; and a cooling step of cooling the stabilized light blocking film.

The substrate may be a light-transmitting substrate or a phase-shifting film deposited on the light-transmitting substrate.

The film forming step may include a first film forming process of forming a first light blocking layer; and a secondary film forming process of forming a second light blocking layer on the first light blocking layer.

The first film forming process and the second process are sequentially performed to form a first light blocking layer and a second light blocking layer, respectively, and a metal target is applied together with an atmosphere gas.

As the metal target, a target of a desired metal may be applied in the case of reactive sputtering, and, for example, if chromium is to be applied as a transition metal, a chromium target may be applied.

The atmosphere gas may be applied differently depending on the desired composition, thickness, density, etc. of the first and/or second light blocking layer, and an inert gas and a reactive gas are mixed.

As the inert gas, argon gas, helium gas, etc. may be applied alone or in combination. The application of the inert gas is considered to be involved in the deposition process in the sputtering process and is removed later in the heat treatment, etc. to be related to the density control of the film.

As the reactive gas, a gas containing an element of nitrogen, an element of oxygen, etc. may be applied alone or in combination. If necessary, carbon dioxide may also be applied. Exemplarily the reactive gas is CO ₂ , O ₂ , N ₂ , NO, NO ₂ , N ₂ O, N ₂ O ₃ , N ₂ O ₄ , N ₂ O ₅ and the like may be applied, but is not limited thereto. These gases may affect the composition of the thin film depending on the amount applied, and may also affect the degree of bonding of elements in the film, the degree of etching, the degree of particle formation, and the like.

The primary atmospheric gas, which is the atmospheric gas of the primary film formation process, is an inert gas, and a low molecular weight inert gas such as argon gas and helium may be applied together. When a low molecular weight inert gas such as helium as well as argon gas is applied as the inert gas, it may help control the density of the light blocking layer to be manufactured. The primary atmosphere gas may include a reactive gas, and the reactive gas may be a gas containing nitrogen, oxygen, or the like described above. The content of the reactive gas in the primary atmosphere gas is related to the content of the reactive gas in the secondary atmosphere gas, which will be described later, so that hardness, Young's modulus, and the like can be more efficiently controlled.

As the secondary atmospheric gas, which is the atmospheric gas of the secondary film formation process, argon gas is applied as an inert gas. For sufficient control of hardness, etc., low molecular weight inert gas such as helium is not separately applied. However, the hardness and the like are controlled by adjusting the content of the reactive gas.

The ratio of the content of the reactive gas included in the secondary atmospheric gas based on the content of the reactive gas included in the primary atmospheric gas may be a volume ratio of 0.7 to 1.1, a volume ratio of 0.8 to 1.05, and 0.85 to 0.95 by volume. When the reactive gas is applied in such a volume ratio, it is easier to control hardness and Young's modulus of the first and second light blocking layers.

DC power applied in the sputtering process may be used, and RF power may be used. Power applied in the sputtering process can be applied in the range of 0.5 to 5.0 kW.

The sputtering time in the first deposition process and the secondary deposition process may be applied in a ratio of 100: 7 to 32. In this case, it is possible to obtain a light-shielding film having an intended appropriate thickness ratio.

The heat treatment step is a process of uniformly applying heat to the entire substrate, and may remove residual stress, etc. that may occur during sputtering, etc., and may further alleviate a whip phenomenon of the photomask blank. The temperature in the heat treatment step may be 150 to 330 ℃. In the heat treatment step, the heat treatment may be performed for about 5 to 50 minutes excluding the temperature increase time.

The cooling step may be cooled to 10 to 30° C. in an air cooling method, and inert gas or dry air may be applied to the air cooling.

The light blocking film 30 thus manufactured includes a first light blocking layer 301 and a second light blocking layer 302 each containing a transition metal and at least one of oxygen and nitrogen.

The second light blocking layer 302 may contain 50 to 80 at% of the transition metal. The second light blocking layer 302 may contain 55 to 75 at% of the transition metal. The second light blocking layer 302 may contain 60 to 70 at% of the transition metal. The sum of the oxygen content and the nitrogen content of the second light blocking layer 302 may be 10 to 30 at%. The sum of the oxygen content and the nitrogen content of the second light blocking layer 302 may be 15 to 25 at%. The second light blocking layer 302 may contain 5 to 15 at% nitrogen. The second light blocking layer 22 may contain 7 to 13 at% nitrogen.

The first light blocking layer 301 may contain 30 to 60 at% of the transition metal. The first light blocking layer 301 may contain 35 to 55 at% of the transition metal. The first light blocking layer 301 may contain 40 to 50 at% of the transition metal. The sum of the oxygen content and the nitrogen content of the first light blocking layer 301 may be 40 to 70 at%. The sum of the oxygen content and the nitrogen content of the first light blocking layer 301 may be 45 to 65 at%. The sum of the oxygen content and the nitrogen content of the first light blocking layer 301 may be 50 to 60 at%. The first light blocking layer 301 may contain 20 to 37 at% oxygen. The first light blocking layer 301 may contain 23 to 33 at% oxygen. The first light blocking layer 301 may contain 25 to 30 at% oxygen. The first light blocking layer 301 may contain 20 to 35 at% nitrogen. The first light blocking layer 301 may contain 26 to 33 at% nitrogen. The first light blocking layer 301 may contain 26 to 30 at% nitrogen.

The transition metal may include at least one of Cr, Ta, Ti, and Hf. The transition metal may be Cr.

The phase shift film, the hard mask film, the photomask film, etc. can be manufactured by a conventional manufacturing method, and there is no particular limitation on the method.

Manufacturing method of semiconductor device

It is possible to manufacture a semiconductor device with fewer defects by using the photomask described above.

A method of manufacturing a semiconductor device according to an embodiment includes a preparation step and a patterning step. The preparation step is a step of preparing a target substrate to be patterned.

The target substrate may be a wafer, an electrically conductive layer or an insulating layer formed on the wafer, a glass substrate, etc., but is not limited thereto.

The patterning step is a step of manufacturing a patterned target substrate through a lithography process by applying a photomask on one surface of the target substrate. As the lithography process, a conventional lithography process may be applied, and specifically, a lithography process using a 193 nm ArF light source may be applied.

Specifically, a light source; a photomask positioned on the light path of the light source; and a target substrate including a photoresist layer, and the light emitting from the light source and passing through the photomask is transmitted to the photoresist layer of the target substrate. At this time, the properties of the photoresist film of the target substrate are changed by the light, and a pattern is formed on the target substrate through a process such as developing it.

The patterned target substrate may have a fine wiring pattern made of a semiconductor material by repeating processes such as formation of an electrically conductive layer, planarization, and formation of an insulating layer, and may be manufactured as a semiconductor device.

In the method of manufacturing the semiconductor device, a pattern with fewer defects can be obtained by applying the above-described embodiment, and it is possible to efficiently manufacture a semiconductor material of excellent quality.

Hereinafter, it will be described in more detail through specific examples. The following examples are merely illustrative to help the understanding of the present invention, and the scope of the present invention is not limited thereto.

Preparation Example: Preparation of a light-shielding film

The same substrate having the same phase reversal effect of about 180° for a wavelength of 193 nm was prepared on a synthetic quartz light-transmitting substrate having a width of 6 inches, a length of 6 inches, and a thickness of 0.25 inches, and the following was applied to the production of a light-shielding film.

The substrate was placed in a chamber of DC sputtering equipment, and the T/S distance of the chromium target was 255 mm, and the angle between the substrate and the target was 25 degrees. The electric power applied when forming the first light-shielding layer was 1.85 kWh, and the electric power applied to the film-forming of the second light-shielding layer was 1.5 kWh.

Sputtering was performed as shown in Table 1 by applying the following atmospheric gas while rotating the substrate, and a light blocking layer was formed by sequentially forming a first light blocking layer and a second light blocking layer, respectively. The heat treatment was applied in the same manner at 200 °C for 15 minutes, and the light-shielding film after the heat treatment was cooled by applying dry air for 5 minutes in an atmosphere of 20 °C.

floor type Deposition time (s) atmosphere gas volume ratio Reactive Gas Ratio# Ar gas reactive gas He gas
(low molecular weight
inert gas) Example 1 first light blocking layer 230-300 21 43* 36 One 2nd light blocking layer 20-28 57 43* 0 Example 2 first light blocking layer 230-300 19 47** 34 0.915 2nd light blocking layer 20-28 57 43* 0 Example 3 first light blocking layer 230-300 17 53*** 30 0.811 2nd light blocking layer 20-28 57 43* 0 Comparative Example 1 first light blocking layer 230-300 21 43* 36 - 2nd light blocking layer - - - - Comparative Example 2 first light blocking layer 230-300 21 43* 36 1.302 2nd light blocking layer 20-28 44 56 0 Comparative Example 3 first light blocking layer 230-300 19 47** 34 0.426 2nd light blocking layer 20-28 80 20 0

# Ratio (volume ratio) of reactive gas applied when forming the second light-shielding layer based on the reactive gas applied when forming the first light-shielding layer

* Reactive gas 43 is applied in the volume ratio of N ₂ 11 and CO ₂ 32.

** Reactive gas 47 is applied as a volume ratio of N ₂ 11 and CO ₂ 36.

*** Reactive gas 53 is applied as a volume ratio of N ₂ 24 and CO ₂ 29.

- A total amount of N ₂ is applied for the reactive gas of the second light blocking layer.

Experimental example: evaluation of physical properties such as hardness and Young's modulus

Hardness, Young's modulus, separation force, adhesion force, etc. were measured by AMF. Using Park System's AFM equipment (equipment model XE-150), the scan rate was 0.5Hz, contact mode, cantilever model Park System's PPP-CONTSCR was applied to measure, and the adhesive force was measured at 16 points within the measurement target. was measured and the average value was taken, and the hardness or Young's modulus values obtained therefrom are shown in Table 3 below as the above hardness or Young's modulus values. The measured data at 16 points in Example 2 are presented in Table 2. For the measuring tip applied during measurement, a Berkovich tip made of silicon (Poisson's ratio of the tip: 0.07) is applied. .

measuring point first light blocking layer 2nd light blocking layer Separation force (nN) Adhesion (fJ) Separation force (nN) Adhesion (fJ) One 3.7 0.22 4.55 0.35 2 3.68 0.21 4.41 0.33 3 3.63 0.21 4.41 0.33 4 3.59 0.2 4.37 0.32 5 3.53 0.2 4.4 0.33 6 3.52 0.19 4.31 0.32 7 3.47 0.19 4.39 0.33 8 3.61 0.2 4.27 0.32 9 3.57 0.2 4.34 0.31 10 3.45 0.19 4.29 0.31 11 3.56 0.2 4.41 0.34 12 3.45 0.19 4.36 0.33 13 3.36 0.18 4.37 0.33 14 3.52 0.19 4.29 0.3 15 3.49 0.19 4.18 0.3 16 3.47 0.19 4.27 0.3 Average 3.538 0.197 4.351 0.322 Standard Deviation* 0.091 0.010 0.084 0.015 Ratio of standard deviation to mean (%) 2.567 5.153 1.935 4.569

* For standard deviation, Excel's STDEV.S function is applied.

The optical properties were measured by a conventional method using an ellipsometer, and the transmittance and optical density of the entire light-shielding film are shown in Table 3 below along with information such as hardness and Young's modulus.

The etching ratio was performed under the same conditions by a conventional dry etching method applying a chlorine-based gas.

floor type Hardness
(kPa) hardness ratio* Young's modulus
(kPa) Young's modulus ratio** transmittance optical density Etching rate
(Etch Rate) Example 1 first light blocking layer 1.331 0.370 7.403 0.372 1.323 1.88 1.6 Å/s 2nd light blocking layer 0.493 2.751 Example 2 first light blocking layer 1.630 0.302 9.040 0.305 1.412 1.85 1.8 Å/s 2nd light blocking layer 0.493 2.760 Example 3 first light blocking layer 2.050 0.242 11.314 0.246 1.526 1.82 1.9 Å/s 2nd light blocking layer 0.496 2.780 Comparative Example 1 first light blocking layer - - - - 1.415 1.85 1.9 Å/s 2nd light blocking layer - - Comparative Example 2 first light blocking layer 1.338 0.618 7.453 0.621 1.417 1.85 1.7 Å/s 2nd light blocking layer 0.828 4.626 Comparative Example 3 first light blocking layer 1.640 0.102 9.101 0.101 0.993 2.02 1.1 Å/s 2nd light blocking layer 0.167 0.920

* The hardness ratio is the ratio of the hardness of the second light-shielding layer based on the hardness of the first light-shielding layer.

** Young's modulus ratio is the ratio of the Young's modulus of the second light-shielding layer to the Young's modulus of the first light-shielding layer.

Comparative Example 1 is a single-layer light-shielding film in which the Young's modulus is not controlled, and a large number of particles are formed in the cleaning process, etc., and as one of the causes, attention was paid to the damage occurring at the corner of the light-shielding film pattern, suppressing the generation of such particles, and Hardness, Young's modulus, etc. were controlled to prevent damage to the mask. Since it is necessary to have characteristics capable of reducing particle generation such as hardness while maintaining the optical properties required for the light-shielding film of the photomask, when the metal content of the second light-shielding layer is too high as in Comparative Example 2, hardness control Since the effect was insignificant, the particle improvement effect was insignificant, and when the hardness of the second light blocking layer was too low, it was difficult to control the etching characteristics. In the case of Examples 1 to 3, it was confirmed that the desired control effect of hardness, Young's modulus, etc. could be obtained while maintaining appropriate etching characteristics.

In particular, in the case of Example 2, certain physical properties were confirmed as a whole, and it was confirmed that the particle reduction effect, the particle property scratch reduction effect, etc. were the most excellent. In the case of the comparative example, the scratch defect evaluation result is shown in Figs. 7a and 7b, respectively, showing an example of inspection results (image inspection with HF filter) through an inspection machine. 7a is an inspection result of Comparative Example 1, it was confirmed that the generation of large scratchy particles and a large number of particles. As shown in the schematic diagrams of FIGS. 6A and 6B, the size of the generated particles is large, and it is thought that scratching particles are easily induced as a result. FIG. 7b shows that although the size and number of stretchable particles decreased as a result of the inspection of Comparative Example 2, it was confirmed that the particle generation frequency was still significant.

Although preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements by those skilled in the art using the basic concept of the present invention as defined in the following claims are also provided. is within the scope of the

100: photomask blank 300: photomask
10: light transmissive substrate 20: phase shift film
23: patterned phase shift film 30: light blocking film
33: patterned light blocking film 301: first light blocking layer
302: second light blocking layer 331: patterned first light blocking layer
332: patterned second light blocking layer P: particles

Claims (13)

light transmissive substrate; and
Including; a multi-layered light-shielding film disposed on the light-transmitting substrate;
The light-shielding film,
a first light blocking layer having a first Young's modulus; and
a second light-blocking layer having a second Young's modulus; and
The first light blocking layer is disposed closer to the light-transmitting substrate than the second light blocking layer,
The first Young's modulus is a value greater than the second Young's modulus;
The light-shielding film contains any one transition metal selected from the group consisting of Cr, Ta, Ti and Hf, and nitrogen,
The first Young's modulus is 7 to 13 kPa,
The second Young's modulus is 1.0 to 4.2 kPa,
The second Young's modulus is 0.246 to 0.372 times the first Young's modulus.
delete delete According to claim 1,
The second light blocking layer has a hardness of 0.3 to 0.55 kPa, a photomask blank.
delete According to claim 1,
The thickness of the second light blocking layer is 30 nm or more, a photomask blank.
The method of claim 1,
The second light blocking layer has a value in which the standard deviation of the adhesive force measured at 16 different positions is 8% or less of the average of the adhesive force, the photomask blank.
According to claim 1,
The second light blocking layer has a value in which a standard deviation of the separation force measured at 16 different positions is 5% or less of the average separation force, a photomask blank.
light transmissive substrate; and
Including; a multi-layer patterned light blocking film disposed on the light-transmitting substrate;
The patterned light blocking film,
a patterned first light blocking layer having a first Young's modulus; and
Including; a patterned second light-blocking layer having a second Young's modulus;
The patterned first light-blocking layer is disposed closer to the light-transmitting substrate than the patterned second light-blocking layer,
The first Young's modulus is a value greater than the second Young's modulus;
The light-shielding film contains any one transition metal selected from the group consisting of Cr, Ta, Ti and Hf, and nitrogen,
The first Young's modulus is 7 to 13 kPa,
The second Young's modulus is 1.0 to 4.2 kPa,
The second Young's modulus is 0.246 to 0.372 times the first Young's modulus.
delete A preparation step of preparing a target substrate; And
a patterning step of applying a photomask on one surface of the target substrate to pattern it to produce a patterned target substrate;
To manufacture a semiconductor device, including
The photomask according to claim 9,
A method of manufacturing a semiconductor device.
According to claim 1,
The second light blocking layer comprises 50 to 80 at% of the transition metal, a photomask blank.
According to claim 1,
The second light blocking layer comprises 30 to 60 at% of the transition metal, a photomask blank.

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