KR20070073613A - Blank mask and manufacturing method of photo-mask using the same - Google Patents

Abstract

A blank mask and a method for manufacturing a photomask using the same are provided to improve linearity and fidelity of the photomask without the increase of defects by reducing the thickness of a photoresist layer using a hard mask layer before a photoresist coating process. A blank mask includes a transparent substrate(1), an etch stop layer, a light shielding layer, a hard mask layer and a photoresist layer. The etch stop layer(2) is stacked on the transparent substrate. The light shielding layer(3) is formed on the etch stop layer. The hard mask layer(5) is formed on the light shielding layer. The photoresist layer(6) is coated on the hard mask layer.

Description

Blank mask and manufacturing method of photo-mask using the same

1 schematically shows the form of a single pattern and a dense pattern of a photomask.

2A to 2E illustrate a blank mask and a method of manufacturing a photomask using the same according to the present invention.

3A to 3D illustrate a blank mask and a photomask manufacturing method using the same according to the present invention.

4A to 4F illustrate a blank mask and a photomask manufacturing method using the same according to the present invention.

5A to 5D illustrate a blank mask and a method of manufacturing a photomask using the same according to the present invention.

Figure 6 shows a comparison of the measurement results of the photomask using a blank mask according to the present invention and the photomask using a conventional blank mask.

** Description of the symbols for the main parts of the drawings **

1: transparent substrate 2: etch stop film

3: shading film 4: anti-reflection film

5: hard mask film 6: photoresist

7: phase inversion film 100a: single pattern

100b: dense pattern

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a photomask used in the manufacture of semiconductor integrated circuits, liquid crystal displays, and the like, and a method of manufacturing a blank mask, which is a disc.

In general, in the manufacture of semiconductor integrated circuits and liquid crystal display devices, lithography methods are generally used to process fine patterns. Due to the characteristics of the semiconductor integrated circuit or liquid crystal display industry, there is a continuous demand for technology capable of forming finer patterns. As a result, a finer pattern photomask is required.

In general, a blank mask and a photomask are manufactured by laminating a light shielding film and an antireflection film on a transparent substrate or a substrate on which a phase inversion film is laminated on a transparent substrate, and then coating the photoresist and then exposing, developing, etching and stripping the photoresist. Since the pattern of the conventional blank mask and the photomask is thick because the thickness of the photoresist is thick, even when exposed to the same size to the photoresist alone, as shown in FIG. 1 by micro loading effect (Micro Loading Effect) during etching. There was a problem that the size of the pattern (100a, Isolation Pattern) and the dense pattern (100b, Dense Pattern) is different from each other.

Conventionally, the CD difference is not a big problem because the size of the photomask minimum line width (hereinafter, referred to as CD) is large, but in the case of a photomask that manufactures a pattern having a CD having a CD of 100 nm or less, a single pattern compared to a CD This is a serious problem because the ratio of the CD difference between the 100a and the dense pattern 100b is large.

In addition, the conventional photomask has a problem in that linearity and fidelity of the pattern size and shape become worse as the CD of the photomask pattern is formed smaller.

The above problem generally occurs because the thickness of the photoresist that acts as an etch mask is higher than the pattern size and the thickness of the light shielding film. When the thickness of the photoresist is thicker than the pattern size, the single pattern 100a and the dense pattern 100b are used. It is known to occur because the reaction rate and removal rate of the developer, the etchant or the etching gas and the reactant are different.

Therefore, the photomask design becomes very difficult because the CD difference between the single pattern 100a and the dense pattern 100b has to be designed in consideration of the above problems, and the degree varies depending on the photomask manufacturing process. It has been very difficult to produce high quality photomasks. Therefore, as the CD continues to decrease, it becomes more problematic and serves as a limiting factor for pattern refinement.

In order to solve the above problem, lowering the thickness of the photoresist improves the loading effect and the linearity and fidelity of the fine pattern. However, when the photomask is manufactured by dry etching, the etching ratio between the photoresist and the etching material is not high, so the photo during etching Since the resist is removed and the thin film layer underneath is damaged, a defect occurs on the surface of the photomask, or a photoresist having a thin thickness remains during etching, and thus the photoresist and thin film layer are etched by the etching gas even if the thin film layer is not damaged. The photoresist remaining during the strip process is hardly removed or minute pores defects in the photoresist are generated by the dry etching, resulting in pinholes due to dry etching, which causes damage to the photomask after etching and stripping. There was a problem causing a defect.

The conventional hard mask proposed to solve the above problems is molybdenum (Mo), molybdenum silicide (MoSi), hafnium (Hf), zirconium (Zr), tin (Sn) on the chromium-based light-shielding film and the anti-reflection film , Iron (Fe), nickel silicide (NiSi), cobalt silicide (CoSi) -based hard masks are laminated, but the material constituting the hard mask is not etched by the chromium light-shielding film and the anti-reflection film and dry etching Since wet etching is difficult except for the etching solution containing hydrofluoric acid (HF), which is an etching solution that damages the transparent substrate, the process must be performed only by dry etching, and the surface of the chrome shading film and the anti-reflection film is damaged when the hard mask is removed. There was a problem of increasing the defect of the mask.

The present invention has been made to solve the above problems, using a blank mask laminated with a hard mask film to improve the loading effect, linearity and fidelity, and to reduce the defects on the surface of the light-shielding film or anti-reflection film and a manufacturing method thereof It aims to provide.

In addition, another object of the present invention is a photomask manufactured by an etching method including at least dry etching using a blank mask and a photomask coated with a thin photoresist of less than 300nm and the substrate and the surface without damaging the substrate and the surface It is an object to provide a manufacturing method.

Another object of the present invention is to provide a photomask and a method of manufacturing the same by minimizing damage to a transparent substrate or a phase inversion film by using the blank mask on which the etch stop layer is laminated.

In order to solve the above technical problem, the blank mask according to the present invention is a transparent substrate; An etch stop layer stacked on the transparent substrate; A light blocking layer stacked on the etch stop layer; A hard mask layer stacked on the light shielding layer; And a photoresist coated on the hard mask layer.

In particular, the hard mask layer may have the same etching characteristics as that of the etch stop layer, and may have different etching characteristics from the shading layer, and the hard mask layer may have a dry etching ratio of 3 or more, and a wet etching ratio of 10 or more. .

In addition, it is preferable that an antireflection film having the same etching characteristics as the light blocking film is further stacked between the light blocking film and the hard mask film.

Another blank mask according to the present invention is a transparent substrate; An etch stop layer stacked on the transparent substrate; A light blocking layer stacked on the etch stop layer; An anti-reflection film stacked on the light shielding film; A hard mask layer stacked on the anti-reflection film; And a photoresist coated on the hard mask layer.

In particular, the hard mask layer may have the same etching characteristics as those of the etch stop layer and the light shielding layer, and may have different etching characteristics from the anti-reflection layer, and the hard mask layer may have a dry etching ratio of 3 or more, and a wet etching ratio of 10. It is preferable that it is above.

Another blank mask according to the present invention is a transparent substrate; A light blocking film laminated on the transparent substrate; An anti-reflection film stacked on the light shielding film; A hard mask layer stacked on the anti-reflection film; And a photoresist coated on the hard mask layer.

In particular, the hard mask layer may have the same etching characteristics as the light shielding layer, and may have different etching characteristics from the anti-reflection layer, and the hard mask layer may have a dry etching ratio of 3 or more and a wet etching ratio of 10 or more. .

In any of the above cases, the etch stop layer, the light shielding layer, the antireflection layer, and the hard mask layer may include cobalt (Co), tantalum (Ta), tungsten (W), molybdenum (Mo), vanadium (V), and palladium (Pd). , Titanium (Ti), niobium (Nb), zinc (Zn), hafnium (Hf), germanium (Ge), chromium (Cr), aluminum (Al), platinum (Pt), manganese (Mn), iron (Fe) , Silicon (Si), molybdenum silicide (MoSi), nickel (Ni), cadmium (Cd), zirconium (Zr), magnesium Mg), lithium (Li), selenium (Se), copper (Cu), yttrium (Y), sulfur (S), indium tin oxide (ITO), at least one metal selected from the group consisting of ruthenium (Ru), or oxygen (O), nitrogen (N) to the at least one or more selected metals It is preferably a metal compound containing at least one of carbon (C), fluorine (F), chlorine (Cl), hydrogen (H) and boron (B).

The etch stop layer may have a thickness of 3 to 100 nm, the hard mask layer may have a thickness of 3 to 200 nm, and the surface roughness of any one of the light blocking film, the antireflection film, and the hard mask film may be 0.2 to 5 nm RMS.

In addition, the optical density of the film including the etch stop film, the light shielding film, and the antireflection film or the film including the light blocking film and the antireflection film is preferably 2 to 6 with respect to the exposure light of 157 nm or 193 nm or 248 nm.

In addition, the phase inversion film is preferably further laminated on the transparent substrate.

In addition, the photoresist is preferably coated with a thickness of 10 to 300nm.

In addition, it is preferable that the hard mask film has a reflectance of 5 to 30% with respect to the photomask exposure wavelength, and the hard mask film has a surface resistance of 1 to 500 k? / □.

A method of manufacturing a photomask according to the present invention for transferring a pattern of the same shape onto a silicon wafer by using the blank mask includes exposing and developing the blank mask to form a photoresist pattern; Etching the hard mask layer to form a hard mask layer pattern; Etching the light blocking film to form a light blocking film pattern; And simultaneously etching the etch stop layer and the hard mask layer to simultaneously perform the formation of the etch stop layer pattern and the removal of the hard mask layer pattern.

Another method of manufacturing a photomask according to the present invention for transferring a pattern of the same shape onto a silicon wafer using the blank mask includes exposing and developing the blank mask to form a photoresist pattern; Etching the hard mask layer to form a hard mask layer pattern; Etching the anti-reflection film to form an anti-reflection film pattern; And simultaneously etching the light blocking film and the etch stop film to form the light blocking film pattern and the etch stop film pattern, and etching the hard mask film to simultaneously remove the hard mask film pattern.

Another method of manufacturing a photomask according to the present invention for transferring a pattern of the same shape onto a silicon wafer using the blank mask includes exposing and developing the blank mask to form a photoresist pattern; Etching the hard mask layer to form a hard mask layer pattern; Etching the anti-reflection film to form an anti-reflection film pattern; And etching the light blocking film to form the light blocking film pattern, and simultaneously etching the hard mask film pattern to remove the hard mask film pattern.

Hereinafter, a blank mask and a photomask manufacturing method according to the present invention will be described in more detail.

In order to achieve the above object, in the present invention, a blank mask, which is a raw material of a photomask, is laminated on the transparent substrate 1 or the phase inversion film 6 on which the transparent substrate 1 is laminated. It is preferable to stack at least the light shielding film 3 and the hard mask film 5 thereon.

In this case, the hard mask film 5 should have a thinner thickness than the photoresist 7 and have etching characteristics different from those of the light blocking film 3. In addition, the light blocking film 3 and the etch stop film 2 should have different etching characteristics, and the hard mask film 5 and the etch stop film 2 may have different etching characteristics, but may have the same etching characteristics. It is more preferable to have.

For example, chromium nitride (CrN) is deposited on the transparent substrate 1 or the phase inversion film 6 laminated on the transparent substrate 1 by the etch stop film 2, and the molybdenum silicon (3) is used as the light shielding film 3. MoSi) can be laminated and chromium oxynitride (CrON) can be laminated with the hard mask film 5.

When the stack is formed as described above, the photoresist 7 pattern is formed by exposure and development of the photoresist 7, and then the hard mask film 5 is etched to form the same hard mask film 5 as the photoresist 7 pattern. When the pattern is formed, the photoresist 7 pattern is removed, and the light shielding film 3 is etched using the hard mask film 5 pattern as an etching mask, the thickness of the hard mask film 5 is larger than that of the photoresist 7 pattern. Since the thickness is thin, the CD difference between the single pattern 100a and the dense pattern 100b may be reduced.

In addition, since the photoresist 7 pattern is removed after only the thin hard mask film 5 is etched, the photoresist 7 is considered in consideration of the dry etching ratio between the photoresist 7 and the hard mask film 5. There is an advantage that can significantly reduce the thickness. In addition, when the thickness of the photoresist 7 is thinner than the thickness of the conventional photoresist 7, the photoresist 7 pattern and the hard mask layer may be removed without etching the photoresist 7 pattern after etching the hard mask layer 5. 5) It is also possible to remove the photoresist 7 pattern after etching the light shielding film 3 using the pattern as an etching mask.

In this case, the effect of reducing the CD difference between the single pattern 100a and the dense pattern 100b may be reduced, but the photomask manufacturing process may be simplified and the removal of the hard mask film 5 may be easy and smooth.

Further, in order to achieve the above object, the present invention more preferably further laminates the antireflection film 4 on the light shielding film 3 of the blank mask. The anti-reflection film 4 may be made of a material having the same etching characteristics as the light blocking film 3, or may be made of a material having an etching characteristic different from that of the light blocking film 3.

When the anti-reflection film 4 has the same etching characteristics as the light blocking film 3, the anti-reflection film 4 is simultaneously etched with the light blocking film 3 to form the same pattern. For example, on the transparent substrate 1, an anti-reflection film 4 such as an etch-resistant film 2 of chromium nitride (CrN), a light shielding film 3 of molybdenum silicon (MoSi), or a molybdenum silicon nitride (MoSiN), It is possible to stack chromium oxynitride (CrON) in order.

On the contrary, when the anti-reflection film 4 has an etching characteristic different from that of the light blocking film 3, the anti-reflection film 4 forms the same pattern as the light blocking film 3, but the anti-reflection film 4 is etched when the hard mask film 5 is etched. Since the etch stop serves to prevent etching, the light blocking film 3 may be made of a material having the same etching characteristics as the hard mask film 5.

For example, on the transparent substrate 1, an etch stop film 2 of chromium nitride (CrN), a light shielding film 3 such as chromium carbide nitride (CrCN), an antireflection film 4 such as molybdenum silicon nitride (MoSiN), etc. It is possible to laminate the hard mask film 5 of chromium oxynitride (CrON) in order. In this case, although the light shielding film 3 has the same etching characteristics as the hard mask film 5, the anti-reflection film 4 serves as an etch stop and thus is not etched when the hard mask film 5 is etched.

In addition, since the light shielding film 3 has the same etching characteristics as the hard mask film 5, it is possible to simultaneously remove the hard mask film 5 and simultaneously etch the light shielding film 3 and the etch stop film 2 below. have. At this time, since the light shielding film 3 and the etch stop film 2 are sequentially etched from above, the light shielding film 3 and the etch stop film 2 have a lower etch stop film to obtain a vertical pattern cross section. It is preferable that the etching rate is slower than (2).

Further, in order to achieve the above object, the present invention provides a light shielding film 3 and a transparent substrate 1 or phase on a phase inversion film 6 in which a blank mask is laminated on the transparent substrate 1 or the transparent substrate 1. Laminating a light shielding film 3 that can simultaneously serve as an etch stop film to prevent damage to the inversion film 6, and at the same time acts as an anti-reflection and the etch stop of the hard mask film 5 and the light shielding film 3 on the same. The antireflection film 4 may be stacked and a hard mask film 5 may be stacked thereon, and the antireflection film 4 may have different etching characteristics from the light shielding film 3 and the hard mask film 5. More preferred.

For example, a light shielding film 3 such as chromium carbide nitride (CrCN), which simultaneously serves as the light shielding film 3 and the etch stop film 2, an antireflection film 4 of molybdenum silicon nitride (MoSiN), and chromium oxide It is possible to laminate the hard mask film 5 of nitride (CrON) in order.

When the anti-reflection film 4 has the structure as described above, the anti-reflection film 4 serves as an etch stop to prevent etching of the light shielding film 3 when the hard mask film 5 is etched, and the light shielding film 3 is a light shielding film when the anti-reflection film 4 is etched. (3) serves as an etch stop layer 2 for preventing etching of the transparent substrate 1 or the phase inversion film 6 in the lower portion. In this case, since the etch stop layer is not laminated separately, the process of the blank mask for the hard mask is reduced.

In addition, the present invention, in order to achieve the above object, in order to prevent damage to the underlying layer during the etching and removal of the etching stop film (2) and the hard mask film (5) and the hard stop film (2) and hard The mask film 5 is laminated so that the material constituting the transparent substrate 1, the phase inversion film 6, the antireflection film 4, and / or the light shielding film 3 has a dry etching ratio of 3 or more and a wet etching ratio of 10 or more. It is desirable to. When the dry etching ratio is less than 3, or the wet etching ratio is less than 10, the transparent substrate 1, the phase shift film 6, the anti-reflection film 4, and / or the etch stop film 2 or the hard mask film 5 are etched. Alternatively, the light shielding film 3 may be damaged. In general, the dry and wet etch ratios are calculated by the following equation for the same etchant or etching gas.

Etch Ratio = (etching speed of material to be etched / etching speed of material not to be etched)

In addition, in order to achieve the above object, the present invention preferably coats the photoresist 7 having a thickness of 10 to 300 nm on the blank mask on which the hard mask film 5 is laminated. In the present invention, since the hard mask film 5 is used, the thinner the photoresist 7 is, the better the thickness is. However, the thickness of the photoresist 7 is less than 10 nm, and it is very difficult to achieve the current technology. Insufficient to serve as an etch mask in formation. In addition, when the thickness is 300 nm or more, there is almost no effect due to the reduction of the thickness of the photoresist 7.

In the present invention, since the hard mask film 5 can be further laminated as described above, the thickness can be lowered as compared with the conventional photoresist 7 having a thickness of 300 to 500 nm. Thus, CD characteristics such as linearity and fidelity of the CD can be improved. And there is an effect of reducing the exposure dose for the photomask manufacturing.

In addition, in order to achieve the above object of the present invention, the etch stop layer (2) and the hard mask layer (5) is preferably laminated with a material capable of dry etching or wet etching, the material capable of simultaneous dry etching and wet etching It is more preferable to laminate | stack by.

In general, dry etching has better uniformity, linearity, and fidelity of CD than wet etching. Therefore, when manufacturing a photomask for manufacturing an ultra-high density integrated circuit product having a CD of 100 nm or less, at least a light shielding film (3) or an anti-reflection film It is preferable to perform dry etching (4). In addition, in order to prevent damage to the lower light blocking film 3, the transparent substrate 1, or the phase inversion film 6, the etch stop film 2 and the hard mask film 5 may be wet-etched as well as dry-etched. More preferred.

In addition, in order to achieve the above object, the present invention is preferably laminated so that the surface of the hard mask film 5 has a reflectance of 5 to 30% at the photomask exposure wavelength. In the blank mask for the hard mask 5, since the hard mask film 5 is stacked on the antireflection film 4 and the photoresist 7 is coated thereon, when the hard mask film 5 has a high reflectance, CD manufacturing is difficult to control when manufacturing a photomask, such as a standing wave phenomenon.

The photomask exposure apparatus generally uses a wavelength of about 365 nm at present, and recently, an exposure apparatus using a wavelength of 257 nm has also been developed. When the reflectance is stacked below 5% at the exposure wavelength, there is almost no advantage due to the low reflectance. When the reflectance is 30% or more at the exposure wavelength, the standing wave phenomenon becomes large, which causes a problem in photomask CD control.

In addition, in order to achieve the above object, the present invention is preferably laminated so that the sum of the optical density of the film laminated on the light shielding pattern is 2 to 6 with respect to the exposure light. When the optical density is 2 or less, lithography exposure light, for example, 157 nm, 193 nm, 248 nm, and 365 nm light is transmitted about 1%, so the lithography exposure process using a photomask manufactured using the blank mask is performed. When performed, the 1% transmitted light causes adverse effects such as a decrease in resolution and a reduction in depth of focus (DOF).

On the contrary, in order to make the optical density more than 6, the thickness of the light shielding film needs to be thick, so that it is difficult to accurately manufacture the CD of the photomask, and there is little advantage in terms of resolution and DOF. The optical density is calculated by the following equation.

Optical density = 2-log ₁₀ (transmittance%)

In addition, in order to achieve the above object, in the present invention, the etch stop film 2, the hard mask film 5 and / or the light shielding film 3 may be etched and removed, respectively, but are simultaneously etched and removed. More preferred. Therefore, it is preferable to stack materials having properties that are etched by the same etching solution or etching gas. At this time, the etching rate is preferably an etching ratio of 3 or less.

Further, for the same etching characteristics, it is more preferable to be made of the same metal-based material. Etching and removing the etch stop film 2 and the hard mask film 5 at the same time as described above has the advantage of shortening the photomask manufacturing process and the etch stop film 2 or the hard mask film 5 or the light shielding film 3 ) Is not limited to the manufacturing process since it is not necessary to consider the damage of the remaining film when etching or removing any of them.

In addition, in order to achieve the above object, the present invention, the etch stop film (2), the hard mask film (5) and / or the light shielding film (3) is made of the same metal-based material, tantalum (Ta), chromium (Cr), vanadium (V), palladium (Pd), niobium (Nb), zinc (Zn), germanium (Ge), aluminum (Al), platinum (Pt), manganese (Mn), cadmium (Cd), magnesium Mg), lithium (Li), selenium (Se), copper (Cu), yttrium (Y), sulfur (S), indium tin oxide (ITO), etc. can be selected at least one or more selected from the group consisting of It is desirable to stack with a series of materials. In addition, the metal element is laminated with a material containing at least one of oxygen (O), nitrogen (N), carbon (C), fluorine (F), hydrogen (H), chlorine (Cl), boron (B) It is possible.

In addition, in order to achieve the above object, the present invention, it is preferable that the etch stop film (2) is laminated to a thickness of 3 to 100nm. When the etch stop layer 2 is 3 nm or less, the etch stop layer does not play a role, and when the etch stop layer 2 is 100 nm or more, the undercut of the etch stop layer 2 becomes large, which adversely affects the photomask CD characteristics. Since the etch stop film 2 is etched at the same time as the hard mask film 5, the etch stop film 2 should not be etched too much or too little in consideration of the etching time by the etching solution or the etching gas. ), The thickness of the etch stop film (2) should be properly controlled in consideration of the etching speed. In consideration of the above, it is more preferable that the thickness of the etch stop film 2 is laminated to a thickness of 10 to 50 nm.

In addition, in order to achieve the above object, in the present invention, the hard mask film 5 is preferably composed of 3 to 200 nm. If the thickness of the hard mask film 5 is 3 nm or less, the thickness is too thin, so that the anti-reflection film 4 or the light shielding film 3 may be removed during etching to damage the surface of the anti-reflection film 4 or the light shielding film 3 to manufacture the photomask. It may cause pattern defects later, and also charge up may occur due to low sheet resistance during electron beam exposure for photomask fabrication. When the charge-up phenomenon occurs, pattern defects may occur or the position of the pattern may be shifted to cause pattern position defects. On the contrary, when the thickness of the hard mask film 5 is 200 nm or more, the effect due to the reduction of the etching mask thickness is reduced. In order to prevent the charge up phenomenon during the electron beam exposure and to increase the effect of the hard mask 5, the thickness of the hard mask film 5 is more preferably 10 to 100 nm thick.

In addition, in order to achieve the above object, the present invention, it is to be laminated so that the surface roughness of the etch stop film 2, the light shielding film 3, the antireflection film 4 and the hard mask film 5 to be 0.2 to 5nm RMS. desirable. The lower the surface roughness, the better. However, the surface roughness of the transparent substrate 1 is generally 0.2 nm RMS or more, so it is difficult to be less than that. When 5 nm RMS is used, the film is patterned to produce scattering of transmitted and reflected light in the inspection apparatus. As a result, pattern inspection is difficult, and when the photomask is mounted and used in a lithographic exposure apparatus, pattern defects are likely to occur due to scattering of transmitted light and scattering of reflected light. In order to achieve the surface roughness, the crystal structure of the etch stop film 2, the light shielding film 3, the antireflection film 4, and the hard mask film 5 is more preferably amorphous. 2) In order to make the light shielding film 3, the antireflection film 4, and the hard mask film 5 have an amorphous structure, it is preferable to appropriately select substrate heating temperature, pressure and gas conditions in the thin film stacking.

Moreover, in order to achieve the said objective, in this invention, it is preferable that the sheet resistance of the surface of the said hard mask film 5 shall be 1-500 kohm / square. The smaller the photomask CD, the larger the charge-up phenomenon, so it is necessary to lower the sheet resistance. The lower the sheet resistance, the better. However, the thickness of the hard mask film 5 should be 200 nm or more in order to achieve 1Ω / □. It does not need to be less than 1Ω / □ because there is no remarkable advantage, and it should be kept below 500kΩ / □ because charge-up phenomenon occurs when the sheet resistance exceeds 500kΩ / □.

In order to achieve the above object, the present invention provides at least the light shielding film 3 or the light shielding film 3 because the hard mask film 5 is etched at the same time or at the same time when the hard mask film 5 is etched. It is preferably removed after etching.

The surface of the hard mask film 5 after the anti-reflection film 4 and / or the light shielding film 3 is etched using the hard mask 5 pattern as an etching mask, and then the anti-reflection film 4 and / or the light shielding film 3 Surface damage is caused by the etchant or etching gas.

In addition, since the shading role and the anti-reflection role of the photomask are performed by the shading film 3 and the anti-reflection film 4, the pattern of the hard mask film 5 having completed the patterning may be removed.

In addition, in order to achieve the above object, the present invention provides at least the antireflection film 4 and / or the light shielding film 3 made of a metal material different from that of the hard mask film 5, and cobalt (Co) and tantalum. (Ta), tungsten (W), molybdenum (Mo), chromium (Cr), vanadium (V), palladium (Pd), titanium (Ti), niobium (Nb), zinc (Zn), hafnium (Hf), germanium (Ge), aluminum (Al), platinum (Pt), manganese (Mn), iron (Fe), silicon (Si) nickel (Ni), cadmium (Cd), zirconium (Zr), magnesium (Mg), lithium ( At least one of Li, selenium (Se), copper (Cu), yttrium (Y), sulfur (S), and indium tin oxide (InSnO) may be selected and used, and at least the antireflection film 4 may be made of molybdenum silicon. It is more preferable to set it as a (MoSi) type | system | group substance. In addition, the metal element is laminated with a material containing at least one from oxygen (O), nitrogen (N), carbon (C), fluorine (F), hydrogen (H), chlorine (Cl), boron (B) group It is possible to do

In addition, in order to achieve the above object, the present invention is capable of stripping by stripping by heating a strip solution containing sulfuric acid (H2SO4) as a main component by stripping the remaining photoresist (7). It is also possible to remove by ashing process with a dry etching device. In addition, in order to prevent surface damage of the hard mask film 5, it is also possible to remove the entire surface by treatment with a developer after exposure to ultraviolet light.

In order to achieve the above object, the present invention provides the above-mentioned phase inversion film 6, light shielding film 3, phase inversion film 6, and hard mask film 5 in physical vapor deposition (PVD) and chemical vapor deposition ( Lamination by CVD) and atomic layer deposition (ALD), and more preferably by reactive sputtering in physical vapor deposition (PVD).

In addition, in order to achieve the above object, the present invention, the light shielding film 3 and the anti-reflection film 4 is exposed to the photoresist 7 with a laser of an electron beam or monochromatic light, using the above-mentioned blank mask, And the photoresist 7 pattern is formed, and then the hard mask 5 is etched to form the hard mask film 5 pattern, and the remaining photoresist 7 and the hard mask film 5 are etched at least. The light shielding film 3 is etched, the residual photoresist 7 pattern is removed, the hard mask 5 is removed by wet or dry etching, and the etch stop film 2 is etched at the same time to form the etch stop film 2 pattern. It is preferable to manufacture a photomask by the method. The above method is effective when the thickness of the photoresist 7 is very thin, and the photomask manufacturing process is simplified because the light shielding film 3 is etched without removing the photoresist 7 pattern. In addition, after the exposure and the etching of the hard mask 5, the residual photoresist 7 is first removed, and the light shielding film 3 is etched using the hard mask layer 5 as an etching mask, and then the residual photoresist 7 is removed. It is possible to manufacture the photomask by removing the hard mask 5 by wet etching or dry etching and simultaneously etching the etch stop film 2. In this case, since the photoresist 7 is first removed and the light shielding film 3 is etched using the thin hard mask film 5 pattern as an etching mask, the local loading effect is very small.

In order to achieve the above object, the present invention provides a photoresist using a blank mask in which the light shielding film 3 and the antireflection film 4 coated with a photoresist 7 of 300 nm or less have the same etching characteristics. 7) After exposure and development with an electron beam or a laser of monochromatic light, the hard mask 5 is etched to form a hard mask film 5 pattern, and the remaining photoresist 7 and hard mask film 5 patterns are etch masks. At least the photoresist 7 is removed at the same time as the light shielding film 3 is etched to remove the hard mask 5 by wet etching or dry etching without removing the residual photoresist 7 and simultaneously etching the etch stop layer 2. It is preferable. The above method has the advantage of simplifying the photomask manufacturing process because the photoresist 7 removal process is omitted.

In addition, in order to achieve the above object, the present invention, the light shielding film 3 and the anti-reflection film 4 by using the above-mentioned blank mask having a different etching characteristics to the photoresist 7 as an electron beam or a laser of monochromatic light After exposure and development, the hard mask 5 is etched and the residual photoresist 7 is removed, and then the at least antireflection film 4 is etched using the hard mask film 5 as an etch mask, and the antireflection film 4 pattern is etched. It is preferable to form a pattern by etching the light shielding film 3 and the etch stop film 2, and at the same time, the hard mask film 5 is etched and removed to manufacture a photomask. In the above, since the light shielding film 3 and the etch stop film 2 have the same etching characteristics, it is possible to etch simultaneously. At this time, it is more preferable that the etching rate of the etch stop film 2 is larger than that of the light shielding film 3 for the same etching solution or etching gas so that the pattern cross-sectional profile is improved.

In addition, in order to achieve the above object, according to the present invention, the light shielding film 3 and the anti-reflection film 4 have different etching characteristics, and the light shielding film 3 is etch stop of the transparent substrate 1 or the phase inversion film 6. The above-described blank mask, which simultaneously plays a role, is exposed to the photoresist 7 with an electron beam or a laser of monochromatic light, and after development, the hard mask 5 is etched and the hard mask layer 5 pattern is etched to reflect at least. The protective film 4 is etched and the light shielding film 3 is etched using the hard mask 5 pattern and the antireflection film 4 pattern as an etching mask to form a pattern, and the hard mask film 5 is etched and removed. It is desirable to produce a photomask. The photoresist 7 pattern is most preferably removed after the hard mask film 5 pattern is formed, and may be removed after the anti-reflection film 4 pattern or the light shielding film 3 pattern is formed according to the photomask process. It is possible.

In addition, in order to achieve the above object, the present invention, the anti-reflection film (4) is preferably made of a material having a different etching characteristics than the hard mask film (5) is laminated to a thickness of 3 to 100nm. In the present invention, since the anti-reflection film 4 must simultaneously play the role of an etch stop layer in the process of manufacturing a photomask, when the thickness is 3 nm or less, the antireflection is not only difficult because of high reflectance, but also serves as an etch stop layer because the thickness is too thin. Difficult to do Also, if the thickness is more than 100 nm, the thickness is too thick, which makes precise CD control difficult.

In addition, in order to achieve the above object, the present invention, by using the photoresist (7) pattern as an etching mask, and removing the remaining photoresist (7) after forming the hard mask film (5) pattern pattern inspection is carried out The defects of the hard mask layer 5 pattern are corrected by a method such as a focused ion beam (FIB) and a gas assist etching (GAE), and then the hard mask layer 5 pattern having the defects corrected is used as an etching mask. It is preferable to etch the anti-reflection film 4 and the light shielding film 3 below. According to the above method, defects occurring after the formation of the hard mask film 5 pattern are first corrected, and then the antireflection film 4 and the light shielding film 3 are etched thereunder, so that the defects of the photoresist 7 and the hard mask film are etched. Since defects, exposure and development of (5), and defects generated by the etching process are not transferred to the antireflection film 4 and the light shielding film 3 pattern, there is an advantage that a more advanced photomask can be manufactured.

In addition, in order to achieve the above object, the present invention can be produced by the same method for the production of the phase inversion mask as well as the binary mask.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Hereinafter, embodiments of a blank mask and a method of manufacturing a photomask according to the present invention will be described in detail with reference to the accompanying drawings.

Example 1

2A to 2E illustrate a blank mask and a photomask manufacturing method according to a first embodiment of the present invention.

As shown in FIG. 2A, the blank mask according to the present embodiment includes an etch stop film 2, a light shielding film 3, an antireflection film 4, and a hard mask on the transparent substrate 1 to prevent etching of the transparent substrate. The film 5 and the photoresist 6 are sequentially stacked.

In particular, the etch stop film 2 and the hard mask film 5 have the same etching characteristics, and the light blocking film 3 and the antireflection film 4 have the same etching characteristics, but the light blocking film 3 and the hard mask film 5 ) Are configured to have different etching characteristics.

More specifically, first, a DC power supply is formed on the transparent substrate 1 by a reactive sputtering method using argon (Ar) as a chromium (Cr) target and an inert gas and using nitrogen gas (N2) as a reactive gas. When applied, the etch nitride film 2 of chromium nitride (CrN) was laminated to a thickness of 20 nm. In the case of chromium nitride (CrN), wet etching is possible by CR7-S, which is generally used as a chromium etching solution, and also dry etching is possible by chlorine (Cl2) gas and oxygen (O2) gas. It has a high etching ratio with the substrate 1. In addition, since the optical density is larger than that of chromium carbide oxynitride (CrCON), the thickness of the light shielding film can be reduced, and since the reflectance is high, the reflectance contrast at the rear when the alignment key pattern is formed is large. There is an easy advantage.

Molybdenum silicon (MoSi) was then formed on the etch-low film 2 using molybdenum silicon (MoSi) target and argon (Ar) gas having a composition ratio of 1: 9. Light-shielding film 3 was laminated at a thickness of 40 nm, and an antireflection film 4 of molybdenum silicide nitride (MoSiN) was deposited at a thickness of 12 nm. As described above, when the molybdenum silicon (MoSi) -based material is used as the light shielding film 3 and the anti-reflection film 4, it has a high chemical resistance against sulfuric acid (H 2 SO 4) used as a cleaning liquid and a photoresist removing agent, and thus is stable. A mask process can be performed. In addition, molybdenum silicon (MoSi) can be easily etched with an etching gas such as CF4, SF6, which is an etching gas containing fluorine (F), and an etch stop layer (2) and a hard mask mainly composed of chromium (Cr). It has a high etching ratio with the film (5).

After stacking the light shielding film 3 and the antireflection film 4, the optical density was measured at 3.5 including the etch stop film 2 at 193 nm, the ArF exposure wavelength, and the reflectance on the surface of the antireflection film 4 at 193 nm was 9.5%. It was measured and there was no problem in optical density and reflectance.

20 nm of the chromium carbide oxynitride (CrCON) hard mask film 5 is formed by a reactive sputtering method using a chromium (Cr) target, an argon (Ar) gas, a nitrogen (N2) gas, and a carbon dioxide (CO2) gas thereon. Laminated to thickness.

The hard mask film 5 is preferably made of chromium (Cr) as a main component because the lower molybdenum silicon (MoSi) and dry and wet etching ratios are sufficiently large. In addition, a monochromatic laser is used during the exposure process of the photomask manufacturing process. In the case of using A, the reflectance of the surface of the hard mask layer 5 may be low in order to prevent a standing wave phenomenon. Therefore, chromium carbide oxynitride (CrCON) was selected and laminated over chromium nitride (CrN) having high reflectance.

When the reflectance was measured after the hard mask film 5 was laminated, a reflectance of 17% was measured at an exposure wavelength of 365 nm, which is a photomask, and a reflectance of 21% at another exposure wavelength of 257 nm was no problem.

AES (Auger Electron Spectroscopy) measurement was performed in the depth direction for component analysis of the etch stop film (2), the light shielding film (3), and the antireflection film (4). As a result, the etch stop film 2 measured 52 at% of chromium (Cr), 42 at% of nitrogen, 6 at% of carbon (C) and other impurities, and the light shielding film (3) contained 18 at% of molybdenum (Mo). , 75at% of silicon (Si), 7at% of carbon (C), nitrogen (N), etc., and the antireflection film (4) contains 6at% of molybdenum (Mo), 47at% of silicon (Si), and 45at of nitrogen. %, Carbon (C) was measured as 2 at% as impurities.

Next, a blank mask was prepared by applying 200 μm thick FEP-171, a positive chemically amplified photoresist 7 (CAR) for an electron beam exposure apparatus, and performing a soft bake. .

Conventionally, the thickness of the photoresist 7 is generally 300 to 500 nm, but for the manufacture of finer and more precise photomasks of CD, the thickness of the photoresist 7 is 200 nm, and the thickness of the photoresist 7 is uniform in the substrate. To this end, the viscosity of the photoresist, the amount of photoresist coating, the number of revolutions of each coating step, the drying method, the soft bake temperature, and the like were appropriately changed from the conventional methods and coated using a controlled method.

Next, a method of manufacturing the photomask according to the present embodiment using the blank mask prepared as described above will be described.

The blank mask was exposed and developed using an electron beam exposure apparatus to form a photoresist 7 pattern. The electron beam exposure apparatus exposed a pattern having a CD of 150 to 500 nm using an accelerating voltage of 50 keV, and in view of the photo mask thickness, the exposure amount was appropriately reduced and exposed.

Next, the hard mask layer 5 is etched by a dry etching method using chlorine (Cl 2) gas and oxygen (O 2) gas using the patterned photoresist 7 as a mask to form a hard mask layer 5 pattern. Subsequently (see FIG. 2B), the antireflection film 4 and the light shielding film 3 were sequentially etched by a dry etching method using CF4 gas using the remaining photoresist 7 and the hard mask 5 as a mask. (See FIG. 2C).

The dry etching apparatus used the same etching apparatus of ICP (Inductive Coupled Plasma) method, and the cross-sectional profile of the hard mask layer (5), the light shielding layer (3), and the anti-reflective layer (3) and the anti-reflection layer (4) pattern during dry etching In order to improve the vertical profile and prevent the light blocking film 3 from remaining on the etch stop film 2 surface, the etching was performed in excess of 50% of the etching time. At this time, the etch stop film 2 was hardly etched by CF4 and oxygen (O2) gas, which is the etching gas, and the etch ratio of the light shielding film 3 and the etch stop film 2 defined by the following equation was sufficient as seven.

Etch Ratio = [Etch Rate of Material to be Etched (nm / sec) / Etch Rate of Material Not to be Etched (nm / sec)]

The remaining photoresist 7 was then removed by ashing using oxygen (O 2) gas (see FIG. 2D).

Since the photoresist 7 is almost removed by etching the hard mask film 5, the light shielding film 3, and the anti-reflection film 4, it is possible to omit the ashing process, but it is possible to prevent a pattern defect and to provide a precise CD. In order to obtain the remaining photoresist (7) was removed by leaving more than 100% time to remove enough.

Next, the etch stop layer 2 was patterned while the hard mask layer 5 pattern was etched and removed using the chlorine (Cl 2) and oxygen (O 2) gas (see FIG. 2E). Since the photoresist 7 is removed, the entire surface of the hard mask film 5 pattern is etched and removed, but the etch stop film 3 serves as an etch stop for the anti-reflection film 4 and the light shielding film 3. As a result, the same pattern as that of the light shielding film 3 can be obtained, and the transparent substrate below is hardly etched because the etching ratio is large.

Then, washing was performed to complete the photomask according to the first embodiment of the present invention. Referring to FIG. 2C, when the hard mask layer 5, the anti-reflection layer 4, and the light shielding layer 3 are etched simultaneously, the thickness of the remaining photoresist 7 is reduced but not completely removed. Ashing) was removed through the process.

In addition, although the average square roughness (nmRMS) of the surface of the etch stop film 2 was increased by etching the light shielding film 3, the substrate was not damaged because it was removed during the patterning of the etch stop film 2. Also, after the photoresist 7 was removed, many defects such as residues of the photoresist 7 and halftone pinholes occurred on the surface of the hard mask 5, but were simultaneously removed during etching of the hard mask 5.

When the pattern of the photomask according to the first embodiment of the present invention was examined, the result of Example 1 of FIG. 6 was obtained. The exposure dose is the minimum exposure dose at which the residual photoresist 7 is completely removed during the exposure and development processes, and the size difference between the single pattern 100a and the dense pattern 100b is clear of the 400 nm line and space pattern. The pattern size difference of the () part was measured.

In addition, Fidelity made the measurement area / design area of 400nm hole pattern, and the linearity was the pattern size where the difference in measurement size compared to the design size of the pattern began to change rapidly. In the result of Example 1 of FIG. 5, the pattern size of the single pattern 100a and the dense pattern 100b is extremely good with little difference, and the linearity and fidelity of the pattern are also improved.

In addition, when the average square roughness of the surface of the transparent substrate 1 was measured, there was no damage to the surface of the transparent substrate 1 at 0.5 nm. In addition, when foreign matters and defects of the photomask according to the first embodiment of the present invention were examined, defects such as photoresist 7 residue and halftone pinholes generated on the surface of the antireflection film 4 were satisfactory.

In the first embodiment of the present invention, the anti-reflection film 4 and the light shielding film 3 are etched using the remaining patterns of the photoresist 7 and the hard mask 5 as a mask, but the photoresist 7 is first removed and then hard. It is also possible to etch the antireflection film 4 and the light shielding film 3 using only the mask 5 as a mask.

(Example 2)

3A to 3D illustrate a method of manufacturing a photomask according to a second embodiment of the present invention.

In this embodiment, as shown in Fig. 3A, the same blank mask as in the first embodiment was used.

After the hard mask film 5 pattern is formed, a method of manufacturing a photomask by first removing the photoresist 7 pattern and then using only the hard mask film 5 pattern as an etching mask will be described. The manufacturing apparatus and the detailed process are the same as that of 1st Example, and abbreviate | omit description.

Referring to the drawings, in the same manner as in the first embodiment of the present invention, on the transparent substrate 1, an etch-stopping film 2 of chromium nitride having a thickness of 20 nm and a light shielding film of molybdenum silicide (MoSi) having a thickness of 40 nm are first formed on the transparent substrate 1. ), A 12 nm thick molybdenum silicide nitride (MoSiN) antireflection film (4) and a 10 nm thick chromium carbide oxynitride (CrCON) hard mask film (5) were laminated, and then a positive chemically amplified photoresist (7). FEP-171 (CAR) was coated to a thickness of 200 nm to prepare a blank mask.

The blank mask is schematically shown in FIG. 3A. Then, the photoresist 7 pattern is formed by exposure and development in the same manner as in the first embodiment of the present invention, and then the hard mask layer 5 is dry-etched by using the photoresist 7 pattern as an etching mask. After the film 5 pattern was formed (see FIG. 3B), the remaining photoresist 7 was removed by dipping into a heated solution of sulfuric acid (H 2 SO 4) and hydrogen peroxide (H 2 O 2) (see FIG. 3C).

Then, cleaning was performed to remove foreign substances on the surface of the hard mask film 5 pattern, and then pattern defect inspection devices were used to detect pattern defects resulting from the blank mask, the exposure, the developing process, and the etching process.

The pattern defect inspection was possible because the reflectances at the pattern inspection wavelengths of the clear portion and the non-etched portion of the hard mask film 5 were different from each other.

The detected defects were then corrected for defects in the hard mask film pattern 5 using a focused ion beam (FIB) and gas assist etching (GAE) defect correction apparatus. Then, the anti-reflection film 4 and the light shielding film 3 were sequentially dry-etched using the hard mask 5 as an etching mask (see FIG. 3C).

Then, the hard mask 5 and the etch stop film 2 were simultaneously etched and removed, followed by washing to prepare a photomask according to the second embodiment of the present invention as shown in FIG. 3D. In the present embodiment, unlike the first embodiment, after forming the hard mask film 5 pattern, the photoresist 7 pattern is removed, and the light-shielding film 3 and the anti-reflection film are formed by using the hard mask film 5 pattern having the defect-corrected pattern as an etching mask. Since etching of (4) is possible, there is an advantage in that a photomask having almost no defects can be manufactured, and the difference in the pattern size and the CD linearity and fidelity of the single pattern 100a and the dense pattern 100b of the light shielding film 3 pattern There is an advantage that can be further improved.

(Example 3)

In this embodiment, a method of manufacturing a photomask in a manner different from that of the first embodiment will be described by using a blank mask for a hard mask similar to the first embodiment and coating a thinner photoresist.

The drawings are the same as in the second embodiment and described with reference to FIGS. 3A to 3D, but the detailed manufacturing method is slightly different from the second embodiment according to the contents described below.

Referring to the drawings, in the same manner as in the first embodiment of the present invention, on the transparent substrate 1, an etch-stopping film 2 of chromium nitride having a thickness of 20 nm and a light shielding film of molybdenum silicide (MoSi) having a thickness of 40 nm are first formed on the transparent substrate 1. ), A 12 nm thick molybdenum silicide nitride (MoSiN) antireflection film (4) and a 10 nm thick chromium carbide oxynitride (CrCON) hard mask film (5) were laminated, and then a positive chemically amplified photoresist (7). FEP-171 (CAR) was coated to a thickness of 150 nm to prepare a blank mask. The blank mask is schematically shown in FIG. 3A.

Then, the photoresist 7 pattern is formed by exposure and development in the same manner as in the first embodiment of the present invention, and then the hard mask layer 5 is dry-etched by using the photoresist 7 pattern as an etching mask. After the film 5 pattern was formed, the antireflection film 4 and the light shielding film 3 were sequentially dry-etched using the remaining photoresist 7 and the hard mask 5 as an etching mask.

At this time, the photoresist 7 is very thin (150 nm), and the photoresist 7 is etched with respect to the chromium (Cr) and molybdenum silicon (MoSi) components constituting the hard mask film 5 and the light shielding film 3. Since the ratio is not so large as about 0.5 to 2, the hard mask 5, the antireflection film 4, and the light shielding film 3 are simultaneously etched and completely removed, and only the hard mask 5 serves as a mask during the light shielding film 3 etching. The strip process of removing the photoresist 7 can be omitted (see FIGS. 3B and 3C).

Thereafter, the hard mask 5 and the etch stop film 2 were etched and removed at the same time, followed by washing to prepare a photomask according to the second embodiment of the present invention as shown in FIG. 3D.

When the pattern of the photomask according to the first embodiment of the present invention was inspected, the pattern size of the single pattern 100a and the dense pattern 100b was little good, and the linearity and fidelity of the pattern were also improved. . In addition, the average square roughness of the transparent substrate was 0.6 nm without damage. In addition, when foreign matters and defects of the photomask according to the first embodiment of the present invention were examined, defects such as photoresist 7 residue and halftone pinholes generated on the surface of the antireflection film 4 were satisfactory.

(Example 4)

4A to 4F illustrate a method of manufacturing a phase inversion blank mask and a phase inversion photomask according to a fourth embodiment of the present invention.

In this embodiment, unlike the first to third embodiments, the phase shift film 6 is laminated on the transparent substrate 1, and the phase mask in which the blank mask for hard mask of the first embodiment is stacked thereon. The method of manufacturing a typical photomask is demonstrated.

Referring to the drawings, first, a phase inversion film 7 of molybdenum silicide carbide nitride (MoSiCN) having a thickness of 70 nm is laminated on the transparent substrate 1, and then chromium nitride (CrN) is applied in the same manner as in the first embodiment of the present invention. ) Etch stop film (2), light shielding film (3) of molybdenum silicide (MoSi), antireflection film (4) of molybdenum silicide nitride (MoSiN), and hard mask film of chromium carbide oxynitride (CrCON) ) Was laminated and coated with FEP-171, a positive chemically amplified photoresist 6 (CAR), to a thickness of 200 nm to prepare a phase mask blank mask for a hard mask. The phase inverted blank mask is schematically illustrated in FIG. 4A. Then, the hard mask film 5, the antireflection film 4, the light shielding film 3, the etch stop film 2, and the phase inversion film 7 were exposed and developed in the same manner as in the first embodiment of the present invention. Etching was performed sequentially. In this case, the hard mask layer 5 and the etch stop layer 2 stacked in the chromium series used chlorine (Cl 2) gas and oxygen (O 2) gas as an etching gas, and the reflection layer laminated in the molybdenum silicide (MoSi) series was used. Since the prevention film 4, the light shielding film 3, and the phase inversion film 7 use CF4 gas and oxygen (O2) gas as an etching gas, each film composed of another series of metal series has a different etching rate due to the large etching rate. Etchable.

Then, the remaining photoresist 6 was removed by ashing, followed by foreign material cleaning, pattern inspection, and defect correction. Then, FEP-171 was again coated with a thickness of 200 nm. The above process is schematically illustrated in FIGS. 4b to 4c.

Then, the photoresist 6 is formed by exposing and developing the photoresist 6 in the same manner as the pattern forming method. Then, the hard mask film 5, the antireflection film 4, and the light shielding film 3 Were sequentially etched. When the anti-reflection film 4 and the light shielding film 3 are etched, the etching is performed more than 50%. However, the phase shift film 7 is protected by the etch stop film 2 so that the phase shift film 6 is not etched.

Then, the residual photoresist 6 pattern is removed and the etch stop layer 2 is etched at the same time as the chromium (Cr) -based hard mask layer 5 is removed by etching to form a pattern, thereby completing the phase inversion photomask. . At this time, the surface damages formed on the hard mask film 5 and the etch stop film 2 are removed together during the wet etching. The manufacturing process is shown in Figures 4d to 4f.

When the pattern of the phase reversal photomask according to the fourth embodiment of the present invention was examined, the pattern size of the single pattern 100a and the dense pattern 100b was extremely good with little difference, and the linearity and fidelity of the pattern were also excellent. Improvements were made. In addition, the average square roughness of the transparent substrate was 0.5 nm without damage. In addition, foreign matters and defects of the photomask according to the fourth embodiment of the present invention were examined, and defects such as residues of photoresist 7 and halftone pinholes generated on the surface of the anti-reflection film 4 and the phase inversion film 6 were observed. This was good with almost no.

(Example 5)

Hereinafter, a blank mask and a photomask for the hard mask 5 according to the fifth embodiment of the present invention and a manufacturing method thereof will be described.

In this embodiment, the blank mask structure of the first embodiment is the same (see FIG. 2A), but the material constituting the light shielding film 3 is made of chromium carbide nitride (CrCN), unlike molybdenum silicon (MoSi) of the first embodiment. Therefore, there is a difference in the method of manufacturing the photomask.

Referring to the drawings, first, the etch-stop film 2 of chromium nitride (CrN) is laminated on the transparent substrate 1 in the same manner as in the first embodiment, with a thickness of 20 nm, and unlike the first embodiment, the light shielding film 3 Chromium carbide nitride (CrCN) was deposited to a thickness of 40 nm.

When the etch stop film 2 of chromium nitride (CrN) having a high etching rate is laminated as described above, and the light blocking film 3 of chromium carbide (CrCN) having a slow etching speed is formed, the light shielding film 3 and the etch stop film (2) Since the cross sectional shape of the pattern can be obtained vertically, and the etch stop film 2 directly in contact with the transparent substrate 1 is easy to remove, the etch stop film 2 remaining film does not remain on the substrate. There is an advantage of less foreign matter in the clear pattern.

In addition, since the etching speed of the light shielding film 3 is slow, the side etching directly affecting the CD is reduced, so that it is easy to control the CD.

In general, the greater the amount of nitrogen (N at%) in chromium nitride (CrN), the faster the etching rate, and the higher the amount of carbon, the slower the etching rate. Therefore, the amount of nitrogen in the light shielding film 3 is less than that of the etching stopper film 2, and the carbon is Stacked by adding methane (CH4) gas to be included. Then, the antireflection film 4 of molybdenum silicide nitride (MoSiN) was laminated on the light shielding film 3 to a thickness of 20 nm.

In this embodiment, since the anti-reflection film 4 simultaneously serves as an etch stop and an etch mask, the antireflection film 4 is stacked thicker than the first embodiment.

A hard mask layer 5 of chromium carbide oxynitride (CrCON) was laminated to a thickness of 60 nm, and then a FEP-171, which is a chemically amplified photoresist 7, was coated to a thickness of 200 nm to prepare a blank mask.

In this embodiment, as described below, the hard mask film 5 must be removed by etching and patterning the light blocking film 3 of chromium carbide nitride (CrCN) and the etching stop film of chromium nitride (CrN). In consideration of the removal speed of (5) and the etching speed of the light shielding film 3 and the etch stop film 4, the thickness was laminated thicker than that of the first embodiment (see FIG. 2A).

Then, the exposure and development are performed in the same manner as in the first embodiment, and then the hard mask film 5 is etched to form a hard mask film 5 pattern (see FIG. 2B). At this time, since the lower anti-reflection film 4 serves as an etch stop, the light blocking film and the etch stop film 2 of the chromium carbide nitride (CrCN) below are not etched.

Then, unlike the first embodiment, the remaining photoresist 7 was removed using an oxygen plasma. As a result, the surface of the hard mask 5 pattern was exposed, and the anti-reflection film 4 was etched by a dry etching method using CF 4 using the pattern of the hard mask 5 as a mask. At this time, unlike the first embodiment, since only the anti-reflection film 4 is etched, the etching time is appropriately reduced and etched.

Then, the light shielding film 3 and the etch stop film 2 were simultaneously etched using chlorine (Cl 2) and oxygen (O 2) gases (see FIG. 2E). At this time, since the hard mask film 5 pattern is simultaneously removed and the anti-reflection film 4 serves as an etching mask, there is no problem in forming the pattern.

(Example 6)

5A to 5D show a blank mask and a photomask manufacturing method for the hard mask 5 according to the sixth embodiment of the present invention.

This embodiment describes a blank mask and a photomask for a hard mask 5 manufactured by using a blank mask having a structure different from that of the fourth embodiment, and a manufacturing method thereof. In the present embodiment, a method of manufacturing a photomask using a blank mask of the form in which the etch stop layer 2 is omitted is omitted in the blank mask structure of the fifth embodiment.

First, a light blocking film 3 of chromium carbide nitride (CrCN), which simultaneously serves as the etch stop film 2 and the light blocking film 3 of the fourth embodiment, is laminated on the transparent substrate 1 to a thickness of 45 nm. As the components of the light shielding film 3, the amount of carbon (C) and nitrogen (N) in the light shielding film 3 was properly adjusted in consideration of the etching time with the hard mask film 5. Then, the antireflection film 4 of molybdenum silicide nitride (MoSiN) was laminated to a thickness of 20 nm in the same manner as in the fourth embodiment. Then, in the same manner as in the fifth embodiment, a hard mask film 5 of chromium carbide oxynitride (CrCON) was laminated to a thickness of 40 nm, and then FEP-171, a chemically amplified photoresist 7, was coated to a thickness of 200 nm. As shown in 5a, a blank mask according to this example was prepared.

Then, the photoresist 7 pattern was formed by exposure and development in the same manner as in the fifth embodiment.

Then, the hard mask film 5 is etched using the photoresist 7 pattern as an etching mask in the same manner as in the fifth embodiment to form the hard mask film 5 pattern as shown in FIG. 5B, and then the photoresist 7 ) Pattern was removed.

Next, as in the fifth embodiment, the antireflection film 4 is etched to form the antireflection film 4 pattern as shown in FIG. 5C, and the light shielding film 3 pattern is etched using the antireflection film 4 pattern as an etch mask. And the hard mask film 5 were simultaneously removed to prepare a photomask using the hard mask 5 of FIG. 5D.

In this embodiment, the manufacturing process of the blank mask for the hard mask is shortened by stacking the light blocking film 3 which simultaneously serves as the etch stop film and the light blocking film of the fifth embodiment.

(Comparative Example 1)

Comparative Example 1 was performed to compare the effects of CD linearity and fidelity improvement by reducing the thickness of the photoresist 7 of Examples 1 to 3.

In Comparative Example 1, after lamination of the same light shielding film 3 and the antireflection film 4 as in Example 1, the thickness of the photoresist 7 was exposed to light after coating the thickness of the photoresist 7 without stacking the hard mask film 5, unlike Example 1 And the anti-reflective film 4 and the light-shielding film 3 were etched in the same manner as in Example 1 using only the photoresist 7 pattern as an etching mask to remove the remaining photoresist 7 after etching. .

As shown in FIG. 6, Comparative Example 1 of the present invention did not have a large number of foreign materials and defects in the photomask, but had a large difference in size between the single pattern 100a and the dense pattern 100b and poor fidelity and linearity. Is showing.

(Comparative Example 2)

Comparative Example 2 was performed to compare the surface damage and the defect prevention effect of the hard mask film 5 and the etch stop film 2 of Examples 1 to 3.

Comparative Example 2 differs from Example 1 after lamination of the same light shielding film 3 and antireflection film 4 as in Example 1, and the thickness of the photoresist 7 without laminating the etch stop film 2 and the hard mask film 5. Is coated in the same manner as in Example 1, and then the photoresist remaining after the antireflection film 4 and the light shielding film 3 are etched in the same manner as in Example 1 using only the photoresist 7 pattern as a mask after exposure and development ( 7) was made by removing the method.

As shown in FIG. 6, Comparative Example 2 of the present invention showed a small difference in size between the single pattern 100a and the dense pattern 100b of the photomask, and improved fidelity and linearity. When the light shielding film 3 is etched, the transparent substrate 1 may be damaged and the average square roughness of the transparent substrate 1 may be 2.1 nm, and the remaining photoresist 7 may not be removed. Increased dramatically.

As described above, the blank mask and the photomask for the hard mask of the present invention provide the following effects.

First, since the hard mask film 5 is laminated before the photoresist 7 is coated, it is possible to coat the thickness of the photoresist 7 thinly, thereby increasing the number of photomask defects without increasing the number of photomask defects. And the size difference between the dense pattern 100b and the linearity and fidelity is improved can be produced a photomask.

Second, the etch stop layer 2 and the hard mask layer 5 are laminated with a material having a large etch ratio with the layer stacked below the hard mask 5, and the pattern of the exposure, development, and etch stop layer 2 is formed. Since the hard mask 5 is removed by etching, defects on the surfaces of the transparent substrate 1 and the photomask are reduced.

Third, since the thickness of the photoresist 7 can be reduced without increasing the defect of the photomask, the amount of exposure is reduced when the photomask is manufactured, thereby increasing productivity.

It is to be understood that the invention is not limited to that described above and illustrated in the drawings and that many more modifications and variations are possible within the scope of the following claims.

Claims (28)

Transparent substrate; An etch stop layer stacked on the transparent substrate; A light blocking layer stacked on the etch stop layer; A hard mask layer stacked on the light shielding layer; And And a photoresist coated on the hard mask layer. The method of claim 1, And the hard mask layer has the same etching characteristics as that of the etch stop layer, and has a different etching characteristic from the light blocking layer. The method of claim 2, The blank mask of claim 3, wherein the hard mask layer has a dry etching ratio of 3 or more and a wet etching ratio of 10 or more. The method of claim 2, The blank mask, characterized in that the anti-reflection film is further laminated between the light shielding film and the hard mask film. The method of claim 4, wherein The anti-reflection film is a blank mask, characterized in that having the same etching characteristics as the light shielding film. The method of claim 4, wherein The etch stop layer, the light shielding layer, the antireflection layer, and the hard mask layer, Cobalt (Co), Tantalum (Ta), Tungsten (W), Molybdenum (Mo), Vanadium (V), Palladium (Pd), Titanium (Ti), Niobium (Nb), Zinc (Zn), Hafnium (Hf) ), Germanium (Ge), chromium (Cr), aluminum (Al), platinum (Pt), manganese (Mn), iron (Fe), silicon (Si), molybdenum silicide (MoSi), nickel (Ni), Cadmium (Cd), zirconium (Zr), magnesium Mg), lithium (Li), selenium (Se), copper (Cu), yttrium (Y), sulfur (S), indium tin oxide (ITO), ruthenium (Ru) At least one metal selected from the group consisting of A metal containing at least one of oxygen (O), nitrogen (N), carbon (C), fluorine (F), chlorine (Cl), hydrogen (H) and boron (B) in the at least one selected metal. Blank mask, characterized in that the compound. Transparent substrate; An etch stop layer stacked on the transparent substrate; A light blocking layer stacked on the etch stop layer; An anti-reflection film stacked on the light shielding film; A hard mask layer stacked on the anti-reflection film; And And a photoresist coated on the hard mask layer. The method of claim 7, wherein And the hard mask layer has the same etching characteristics as that of the etch stop layer and the light shielding layer, and has a different etching characteristic from that of the anti-reflective layer. The method of claim 8, The hard mask film has a blank etching ratio between the anti-reflection film and a dry etching ratio of 3 or more, and a wet etching ratio of 10 or more. The method of claim 8, The etch stop layer, the light shielding layer, the antireflection layer, and the hard mask layer, Cobalt (Co), Tantalum (Ta), Tungsten (W), Molybdenum (Mo), Vanadium (V), Palladium (Pd), Titanium (Ti), Niobium (Nb), Zinc (Zn), Hafnium (Hf) ), Germanium (Ge), chromium (Cr), aluminum (Al), platinum (Pt), manganese (Mn), iron (Fe), silicon (Si), molybdenum silicide (MoSi), nickel (Ni), Cadmium (Cd), zirconium (Zr), magnesium Mg), lithium (Li), selenium (Se), copper (Cu), yttrium (Y), sulfur (S), indium tin oxide (ITO), ruthenium (Ru) At least one metal selected from the group consisting of A metal containing at least one of oxygen (O), nitrogen (N), carbon (C), fluorine (F), chlorine (Cl), hydrogen (H) and boron (B) in the at least one selected metal. A blank mask, characterized in that the compound. Transparent substrate; A light blocking film laminated on the transparent substrate; An anti-reflection film stacked on the light shielding film; A hard mask layer stacked on the anti-reflection film; And And a photoresist coated on the hard mask layer. The method of claim 11, And the hard mask layer has the same etching characteristic as that of the light blocking layer, and has a different etching characteristic from that of the anti-reflective layer. The method of claim 12, And the hard mask layer has a dry etching ratio of 3 or more and a wet etching ratio of 10 or more. The method of claim 12, The etch stop layer, the light shielding layer, the antireflection layer, and the hard mask layer, Cobalt (Co), Tantalum (Ta), Tungsten (W), Molybdenum (Mo), Vanadium (V), Palladium (Pd), Titanium (Ti), Niobium (Nb), Zinc (Zn), Hafnium (Hf) ), Germanium (Ge), chromium (Cr), aluminum (Al), platinum (Pt), manganese (Mn), iron (Fe), silicon (Si), molybdenum silicide (MoSi), nickel (Ni), Cadmium (Cd), zirconium (Zr), magnesium Mg), lithium (Li), selenium (Se), copper (Cu), yttrium (Y), sulfur (S), indium tin oxide (ITO), ruthenium ( At least one metal selected from the group consisting of Ru), or A metal containing at least one of oxygen (O), nitrogen (N), carbon (C), fluorine (F), chlorine (Cl), hydrogen (H) and boron (B) in the at least one selected metal. A blank mask, characterized in that the compound. The method according to claim 1 or 7, The etch stop layer is a blank mask, characterized in that the thickness of 3 to 100nm. The method according to any one of claims 1, 7, and 11, The blank mask, characterized in that the hard mask layer has a thickness of 3 to 200nm. The method according to any one of claims 4, 7, and 11, The blank mask, characterized in that the surface roughness of any one of the light-shielding film, anti-reflection film, hard mask film is 0.2 to 5nm RMS. The method according to claim 4 or 7, And the optical density of the film comprising the etch stop film, the light shielding film, and the antireflection film is 2 to 6 with respect to exposure light of 157 nm or 193 nm or 248 nm. The method of claim 11, And a light density of 2 to 6 with respect to exposure light of 157 nm or 193 nm or 248 nm. The method according to any one of claims 1, 7, and 11, A blank mask, characterized in that the phase inversion film is further laminated on the transparent substrate. The method according to any one of claims 1, 7, and 11, The photoresist is blank mask, characterized in that the coating to a thickness of 10 to 300nm. The method according to any one of claims 1, 7, and 11, And said hard mask film has a reflectance of 5 to 30% with respect to the photomask exposure wavelength. The method according to any one of claims 1, 7, and 11, And said hard mask film has a sheet resistance of 1 to 500 k? / □. In the manufacturing method of the photo mask which transfers the pattern of the same form on a silicon wafer using the blank mask of Claim 2, Exposing and developing the blank mask to form a photoresist pattern; Etching the hard mask layer to form a hard mask layer pattern; Etching the light blocking film to form a light blocking film pattern; And And simultaneously etching the etch stop layer and the hard mask layer to simultaneously form an etch stop layer pattern and to remove the hard mask layer pattern. In the manufacturing method of the photomask which transfers the pattern of the same form on a silicon wafer using the blank mask of Claim 8, Exposing and developing the blank mask to form a photoresist pattern; Etching the hard mask layer to form a hard mask layer pattern; Etching the anti-reflection film to form an anti-reflection film pattern; And Simultaneously etching the light blocking film and the etch stop film to form a light blocking film pattern and an etch stop film pattern, and etching the hard mask film to simultaneously remove the hard mask film pattern. . In the manufacturing method of the photomask which transfers the pattern of the same form on a silicon wafer using the blank mask of Claim 12, Exposing and developing the blank mask to form a photoresist pattern; Etching the hard mask layer to form a hard mask layer pattern; Etching the anti-reflection film to form an anti-reflection film pattern; And Etching the light shielding film to form a light shielding film pattern, and simultaneously etching the hard mask film pattern to remove the hard mask film pattern. The method of claim 24, Removing the photoresist pattern after the forming of the hard mask layer pattern or after forming the light blocking layer pattern. The method of claim 25 or 26, Removing the photoresist pattern after the forming of the hard mask layer pattern, or after forming the anti-reflection layer pattern, or after forming the light shielding layer pattern.

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