JP4840879B2 - Gray-tone blank mask, gray-tone photomask, and manufacturing method thereof - Google Patents

Description

  The present invention relates to a blank mask and a photomask used for manufacturing a flat panel display (FPD) product such as a liquid crystal display (LCD), an organic electroluminescent element (OLED), and a plasma display panel (PDP). In particular, the present invention relates to a gray-tone photomask used in a process for reducing the number of processes using a photomask in manufacturing a liquid crystal display (LCD) and a gray-tone blank mask that is a raw material thereof.

  Currently, flat panel display (FPD) products such as liquid crystal display devices (LCDs), organic electroluminescent devices (OLEDs), and plasma display panels (PDPs) have become more sophisticated, sophisticated, and diversified. While its application range is expanded, development of manufacturing process technology that is cheaper and more productive is required. In general, a liquid crystal display (LCD) is manufactured by using a lithography process using a patterned photomask. Recently, the conventional 7,8-mask is used to reduce cost and improve yield. The process is gradually shifted to a 4-mask process. In this 4-mask process, a photomask capable of forming two different patterns in one exposure should be used, and a conventional binary mask blocks the exposure light and transmits the exposure light completely. As shown in FIG. 1 or 2, the 4-mask photomask has a semi-transmissive part pattern that transmits only part of the exposure light in addition to the light-shielding part and the transmissive part, as compared with the pattern of the part. Must be configured.

  As shown in FIG. 1 or FIG. 2, the gray tone blank mask is a raw material for manufacturing a gray tone photomask in which a fine circuit pattern of a light shielding portion, a transmission portion and a semi-transmission portion is formed. Then, a semi-transmissive film, a light shielding film, and an antireflection film are laminated, and then a photoresist is coated. The gray-tone blank mask semi-transparent film should have excellent chemical resistance because it must minimize the change in transmittance due to the cleaning process in the photomask manufacturing process. Therefore, a high etching selectivity with respect to the light shielding film and the antireflection film is required. In addition, in order to minimize the amount of CD (Critical Dimension) change, along with the chemical resistance characteristics in the cleaning process, the semi-transparent film against the etching solution used when etching the light shielding layer and antireflection film during photomask manufacturing However, the light-shielding film and the antireflection film must have a high etching selectivity with respect to an etching solution used for etching the semi-transmissive film. In order to satisfy the above requirements, a method has been proposed in which a semi-permeable membrane is made of a metal compound and an etching solution containing NaOH, KOH, LiOH, and CsOH is heated to about 50 to 130 ° C. (For example, Patent Document 1).

  However, as described above, when the semi-transmissive film is made of a metal compound and wet etching is performed with an etchant containing NaOH, KOH, LiOH, and CsOH to produce a gray tone photomask, the etching rate is low. There was a problem. In order to improve this, the temperature of the etching solution can be increased and the process can be performed to improve the etching rate of the semi-permeable film. However, when the etching solution is heated and used, the process may be caused by a change in the concentration of the etching solution. In addition to being unstable, the etching solution is vaporized, and the vaporized etching solution may be adsorbed and solidified on the mask after being present in the atmosphere, resulting in particles on the mask. In general, when spin etching (Spin Spray) is used for wet etching, the etching liquid is cooled in the process of spraying, and when the semi-permeable film is etched, the semi-permeable film is etched at a temperature other than the actual application temperature. It will be broken. Therefore, when the temperature of the etching solution is increased, the etching process becomes inaccurate and unstable, and it is difficult to control the CD of the semi-transmissive portion pattern. In order to solve the above problem, when the temperature is lowered during wet etching of the semi-permeable film and etched for a long time, the semi-permeable film to be etched is not partially etched on the surface of the transparent substrate, and a thin residual film is formed on the surface. This has a problem in that it affects the transmittance and causes a pattern error of the subject.

  Moreover, the conventional semi-permeable membrane comprising oxygen and nitrogen in a transition metal alloy compound further containing a transition metal has the following problems. In general, when the semipermeable membrane is wet-etched, there is a problem that it is difficult to obtain a vertical cross section by isotropic etching because of a low etching rate. If the lithography process is performed using a gray-tone mask having a large pattern cross-sectional gradient as shown in FIG. 6, the exposure light is scattered at the line edge portion of the mask pattern, resulting in a decrease in resolution. Can be invited. Therefore, it is preferable to use a semitransparent film pattern with a vertical cross section. However, the conventional tantalum compound semipermeable film has a slower etching rate and thus has a larger etching at the side surface, and as a result, it is difficult to obtain a vertical pattern. There was a point.

  In addition, when the semi-transmissive portion is formed using a conventional slit pattern binary mask, there are the following problems. Since a binary blank mask composed of a light shielding film and an antireflection film was used as a slit pattern, the exposure amount was not uniform during exposure. This is because the diffraction phenomenon becomes larger as the pattern size becomes smaller. For this reason, a CD error has occurred on the object to be processed, and it is difficult to form a semi-transmissive portion of the slit pattern because it is difficult to control the exposure amount.

Further, the conventional semi-permeable membrane has to be subjected to a wet etching process for a long time with an etching solution containing NaOH, KOH, LiOH, and CsOH because of the problem of slow wet etching. In order to make the etching faster, heating had to be performed at a temperature of 100 ° C. or higher, but in this case, process instability such as a change in the concentration of the etching solution occurred. In order to eliminate such process instability, a semi-transparent film etching process was performed at a low temperature for a long time, but this caused damage to the transparent substrate and increased the surface roughness. When the surface roughness is increased, the light transmitted through the transparent substrate is diffracted at the time of exposure, which makes it difficult to form an accurate pattern, resulting in a CD error.
Korean Patent Application No. 10-2006-0089844

  The present invention is to solve the above-mentioned problems, and its purpose is to etch the semi-permeable film at a low etching solution temperature by improving the etching rate of the semi-permeable film as compared with the prior art. It is possible to improve the productivity by reducing the etching time, and by reducing the etching time, the change of the surface roughness of the transparent substrate with respect to the etching solution can be minimized, and the semi-transmission part of the slit pattern with a uniform exposure amount can be formed. A metal compound that can form a vertical pattern in a semi-transmissive film, has a high etching selectivity with respect to a light-shielding film, has a high etching process stability, and has excellent chemical resistance to chemical solutions used during cleaning and etching. To provide a gray-tone blank mask and a gray-tone photomask each having a semi-transmissive film and a manufacturing method thereof That.

  Another object of the present invention is to improve the etching rate while lowering the temperature of the etching solution by using one kind or a mixture of two or more kinds of the semi-permeable film etching liquid, and heating the etching liquid. Therefore, there is no change in density even when used, so that there is no change in density. Therefore, it is an object to provide a gray-tone blank mask and a gray-tone photomask that generate less particles while improving process safety, and a method for manufacturing the same.

  In order to achieve the above object, the present invention provides a gray-tone blank mask for manufacturing a gray-tone photomask. With reference to FIG. 4 or FIG. 5, this gray tone blank mask is prepared with a transparent substrate 1, a semi-transmissive film 2 is laminated on the transparent substrate 1, and at least a light shielding film 3 is laminated thereon. It is preferable that an antireflection film 4 is further laminated by the above and a photoresist is coated thereon.

In order to achieve the above object, the present invention selectively forms on the transparent substrate an etching stop film that is not etched by the semi-permeable film etching solution or etching gas before the semi-permeable film is laminated. be able to. This etching stopper film has a function of a semi-permeable film, and includes tantalum (Ta), cobalt (Co), 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), Silicide, molybdenum silicide (MoSi), nickel (Ni), cadmium (Cd), zirconium (Zr), magnesium (Mg), lithium (Li), selenium (Se), copper (Cu), yttrium (Y) Element selected from sulfur, sulfur (S), indium tin oxide (ITO), ruthenium (Ru) alone or 2 It can be produced in alloys containing more. One or more elements of carbon (C), oxygen (O), nitrogen (N), fluorine (F), chlorine (Cl), and hydrogen (H) may be further included. More preferably, it is preferable to add carbon (C) as necessary. Moreover, the etching stopper film has a function of a semi-transmissive film, and when measuring the reflectance from the semi-transmissive film to the transparent substrate side (front side) or from the transparent substrate to the semi-transmissive film side (rear side) . A function of adjusting the reflectance may be provided when measuring the reflectance. The etching stopper film may have an amorphous structure and a thickness of 10 to 1000 mm.

  In order to achieve the above object, according to the present invention, the translucent film 2 is made of tantalum (Ta), cobalt (Co), 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), silicide (Silicide), 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) It can be produced in alloys containing more elements alone or in combination. Note that one or more elements of carbon (C), oxygen (O), nitrogen (N), fluorine (F), chlorine (Cl), and hydrogen (H) may be further included. More preferably, it is preferable to add carbon (C) as necessary.

In order to achieve the above object, the present invention provides a reactive sputtering or vacuum deposition method (PVD, PVD, which is performed by introducing an inert gas and a reactive gas in a vacuum chamber when forming a semipermeable membrane. CVD, ALD, ion beam) is used. At this time, as the reactive gas, methane (CH ₄ ), acetylene (C ₂ H ₂ ), ethylene (C ₂ H ₄ ), propane (C ₃ H ₈ ), vinyl acetylene (C ₄ H ₄ ), divinyl acetylene (C ₆ H ₆ ), butane (C ₄ H ₁₀ ), butylene (C ₄ H ₈ ), ethane (C ₂ H ₆ ), nitrogen (N ₂ ), oxygen (O ₂ ), carbon monoxide (CO), 1 from the group consisting of carbon dioxide (CO ₂ ), fluorocarbon (CF ₄ ), nitrous oxide (N ₂ O), nitrogen oxide (NO), nitrogen dioxide (NO ₂ ), ammonia (NH ₃ ) and fluorine (F) Species or two or more species can be selected and used. It is more preferable to use a reactive gas containing carbon (C) in terms of improving particles, chemical resistance and etching rate. The vacuum degree of the vacuum chamber is 0.1 to 20 mTorr, the applied power is 0.1 to 40 kW, and the mixing ratio of the gas is 5 to 100 vol% of inert gas: reactive gas: 0 to 0 It can be 95 vol%. At this time, the reactive gas can be used alone or in combination of two or more kinds selected from gases containing carbon, oxygen, nitrogen, fluorine, chlorine and hydrogen.

  Moreover, in order to achieve said objective, this invention can make a semi-transmissive part a slit pattern. The slit pattern of the semi-transmissive portion may be a dot in addition to a line and a space, and any pattern can be used as long as the transmittance can be controlled. The form of the semi-transmissive portion may be formed of a single layer of semi-transmissive film, or may be formed of a three-layer structure in which a semi-transmissive film, a light shielding film, and an antireflection film are all laminated. Further, the slit pattern may be constituted by two layers of a light shielding film or a semi-transmissive film and an antireflection film. Depending on the purpose of use, a slit pattern structure can be formed in a single layer or multiple layers, and the present invention is not limited to lines, spaces, and dots, and various patterns can be applied as long as the transmittance can be controlled.

  Moreover, in order to achieve said objective, when using carbon-containing gas when forming the semipermeable membrane of this invention by sputtering, it is preferable that the usage-amount of gas shall be 0.1-20 vol%. If it is 0.1 vol% or less, the effect of improving the etching rate by adding a carbon-containing gas cannot be obtained. If it is 20 vol% or more, the chemical resistance is improved, but the etching rate is lowered. The amount of carbon-containing gas used varies depending on the amount of inert gas or other reactive gas, but it may be used within a range that does not change significantly.

In order to achieve the above object, one kind selected from reactive gases containing nitrogen (N ₂ ) or oxygen (O ₂ ) during the production of the semipermeable membrane of the present invention. Alternatively, by selectively using two or more kinds of reactive gases, a transflective film having a transmittance difference of 1 to 10% from i-line (365 nm) to g-line (436 nm), and transmittance A semi-permeable membrane with a difference of 5% or more can be produced. When a gas containing oxygen (O ₂ ) is used during the production of the semipermeable membrane, it is possible to produce a semipermeable membrane having a transmittance difference of 1 to 10%, and a gas containing oxygen and nitrogen. Can be used to manufacture a semi-permeable membrane having a transmittance difference of 5% or more.

  Further, in order to achieve the above object, the composition ratio of the semipermeable membrane of the present invention is such that the transition metal is 5 to 95 at%, one kind selected from carbon, chlorine, hydrogen, fluorine, nitrogen and oxygen. Or it is preferable that 2 or more types have a composition ratio of 0.1-90 at%. In particular, in the case of carbon, it is preferable to have a composition ratio of 0.1 to 20 at%. This is because the higher the carbon content in the film composition ratio, the better the etching rate with respect to the tantalum etching solution, but when the carbon element other than this tantalum is contained at 20 at% or more, the etching rate is reduced. . If the etching rate is reduced, the temperature of the etching solution must be raised to 100 ° C. or higher in order to increase the etching rate, resulting in process instability. In order to perform etching at a lower temperature, more time is required for the etching process. This leads to a problem that the surface roughness of the transparent substrate is deteriorated. Note that when the above carbon is added, the sheet resistance value is reduced and the surface roughness is also reduced, so that a gray-tone photomask with more excellent CD characteristics can be manufactured.

  In order to achieve the above object, in the present invention, it is preferable that the etching rate is 1 Å / sec or more during the wet and dry etching of the semipermeable membrane. If the etching rate is low at the time of wet etching, productivity is lowered due to difficulty in process control, and the surface roughness of the transparent substrate is deteriorated because it is exposed to the etching solution for a long time. If the etching rate is low during dry etching, it is not preferable in terms of productivity, and some film components etched by the reactive gas used during etching exist in the atmosphere in the chamber, causing particles. This increases the possibility that a vertical cross section will not be formed.

  In order to achieve the above object, according to the present invention, it is preferable that the semipermeable membrane is subjected to an etching time of 300 seconds or less during wet and dry etching. If the dry etching time is 300 seconds or more, there is a risk of exposure to particles that can be generated during the etching process, and the efficiency of the process itself is also reduced, which is extremely undesirable from the viewpoint of productivity. In addition, when the wet etching is performed for 300 seconds or more, the transparent substrate can be damaged, and when exposed to the etching solution for a long time, the etching solution penetrates into the lower part of the patterned semi-transmissive film to form a vertical pattern. It becomes difficult to do.

  In order to achieve the above object, according to the present invention, the semipermeable membrane is formed of sodium hydroxide (NaOH), potassium hydroxide (KOH), lithium hydroxide (LiOH), or cesium hydroxide (CsOH). Etching with any one of the etching solutions selected from the above is preferable. Of these etching solutions, sodium hydroxide (NaOH) and potassium hydroxide (KOH) are more preferably used in terms of particle and process control. At this time, the temperature of the etching solution is preferably 23 ° C. to 100 ° C. At the time of wet etching of the semi-transmissive film 2, the etching rate is too slow at 23 ° C. or lower, which is not suitable for manufacturing a gray-tone photomask. Since it is difficult to completely etch, the control of the transmittance is difficult, and the surface roughness on the transparent substrate on which the transmissive portion is formed is deteriorated due to the influence on the etching solution, which is not preferable. On the other hand, when the temperature of the etching solution is 100 ° C. or higher, the etching solution is vaporized because the temperature is too high, and the concentration of the etching solution changes due to the vaporization of the etching solution, making it difficult to control the etching rate. This leads to process instability that must be maintained continuously. In addition, there is a problem that the components of the etching solution to be vaporized are adsorbed on the mask surface in the atmosphere and act as particles.

  Further, the semi-permeable membrane 2 can be etched even when one or more of the above-mentioned sodium hydroxide (NaOH) and potassium hydroxide (KOH) are mixed and used. When the etching solution is mixed and used, the amount of vaporization is small even when the etching solution temperature is raised, and this widens the range of the etching rate, so that the adjustment of the etching rate of the semi-transmissive film becomes very easy. At this time, the temperature of the etching solution is preferably 23 ° C. to 100 ° C. Of the above-mentioned etching solutions, it is possible to mix and use by adjusting the concentration of NaOH and KOH in terms of improving the etching rate and adjusting the viscosity. At this time, the mixing ratio is preferably NaOH: KOH = 1: 9 to NaOH: KOH = 9: 1, and the concentrations of NaOH and KOH are preferably 5 to 50%. That is, if the etchant concentration is 5% or less, the etching rate is not improved, and if it is 50% or more, the viscosity is high. The etching solution adsorbed on the solid may be solidified into particles, and when the etching solution is left for a long time, precipitation of K, Na, etc. occurs in the aqueous solution, the concentration changes, and acts as particles, It is not suitable as an etching solution for a semipermeable membrane.

  Further, the light shielding film 3 and the antireflection film 4 are preferably chromium or a chromium compound in which one or more selected from oxygen, nitrogen, and carbon are contained in chromium, and is a chromium etching solution CAN. The light shielding film 3 and the antireflection film 4 can be wet-etched with the etching solution containing (Ceric Ammonium Nitrate) with a high etching selectivity with the semi-transmissive film 2.

  In addition, the semi-transmissive film should not change in chemical resistance with respect to CAN which is an etching solution of chromium and chromium compound of the light shielding film 3 and the antireflection film 4. When the etching solution used for etching chromium and chromium compound causes etching of the semi-transmissive film or changes in chemical resistance, CD control becomes difficult due to the change in transmittance. Therefore, the chemical resistance characteristic for CAN is 2 It is preferable that the transmissivity of the semipermeable membrane is 1% inside or outside at the time of dipping.

  Further, the chemical resistance of chromium and chromium compounds in the light-shielding film and the antireflection film should not change with respect to NaOH, KOH, LiOH, and CsOH, which are tantalum and tantalum compound etching solutions in the semi-transmissive film. The semi-transmissive film is etched during the photomask manufacturing process. At this time, if the etching solution of the semi-transmissive film changes the etching or chemical resistance of the side surfaces of the light-shielding film and the antireflection film, the transmittance changes. Since CD control becomes difficult, it is preferable that the transmissivity of the light-shielding film and the antireflection film is 1% or outside when immersed for 2 hours (dipping) in terms of chemical resistance to the etching solution of the semi-transmissive film.

  Further, the semi-transmissive film 2 forming the semi-transmissive portion preferably has a transmittance of 5% to 90% at an exposure wavelength of 300 nm to 500 nm and a thickness of 10 mm to 1000 mm. Here, the transmittance may be appropriately set in accordance with the process of the liquid crystal display device. However, when the transmittance of the semi-transmissive portion is 5% or less, the lithography process is performed using the gray tone photomask. The remaining film thickness of the photoresist 5 on the subject due to the semi-transmissive portion is too thick, so that it is not well separated from the pattern of the photoresist 5 due to the light-shielding portion. Since the remaining film of the photoresist 5 of the subject by the transmission part is too thin, it is not well separated from the pattern of the photoresist 5 by the transmission part. Therefore, it is difficult to perform the mask shortening process. Further, when the thickness of the semi-transmissive film 2 is 10 mm or less, the thickness is too thin, so that it is difficult to control the transmittance and it is very difficult to improve the uniformity of the transmittance within the substrate. Conversely, when the thickness of the semi-transmissive film 2 is 1000 mm or more, it is difficult to obtain a vertical pattern cross section when manufacturing a gray-tone photomask, which leads to a decrease in resolution.

  The phase difference of the semi-transmissive film 2 preferably satisfies the range of 0 ° to 100 ° in the wavelength range of 300 nm to 500 nm that is the exposure wavelength. Since the semi-transmissive film 2 has a refractive index and a thickness different from those of the transparent substrate 1, the semi-transmissive film 2 has a phase difference with the exposure light from the transmissive portion. When the exposure light by the semi-transmissive part pattern 9 in which 2 is laminated overlaps, a light interference phenomenon occurs. At this time, when canceling interference occurs, the exposure intensity decreases at the boundary between the transmissive part pattern 8 and the semi-transmissive part pattern 9, and the subject is liable to be defective. Therefore, it is preferable to control the phase difference of the semi-transmissive film 2 to be 100 ° or less, more preferably within a range of 0 to 50 °, so that no cancellation interference occurs.

The surface roughness of the semipermeable membrane 2 is preferably 0.1 to 5 nmRa, and the crystallization state of the thin film preferably has an amorphous structure. When the surface roughness of the semi-transmissive film 2 is large, for example, when the surface roughness is 5 nmRa or more, the exposure light transmitted through the semi-transmissive film 2 is scattered, and the thickness and CD of the remaining film of the subject photoresist 5 are controlled. It becomes very difficult to do. When producing a semipermeable membrane as described above, the semipermeable membrane is formed using one or more selected from reactive gases such as oxygen (O ₂ ), nitrogen (N ₂ ), and methane (CH ₄ ). By manufacturing, a small surface roughness can be obtained, and this surface roughness tends to increase when the semipermeable membrane 2 is crystallized, so that the semipermeable membrane 2 is amorphous. It is preferable.

  In addition, the front surface (Front Side) reflectance difference between the antireflection film 4 and the semi-transmissive film 2 is at least 10% to 90% with respect to the inspection wavelength of the photomask or the alignment wavelength during mask exposure. It is preferable. Unlike the conventional binary mask, the gray-tone photomask has a semi-transmission part pattern 9. Therefore, the semi-transmission part pattern 9 and the light-shielding part and the transmission part pattern 8 must be separated during pattern inspection. Pattern inspection or mask exposure alignment is usually performed by irradiating a photomask with a monochromatic laser and comparing the intensity of reflected light reflected by the light-shielding portion pattern 7 and the semi-transmissive portion pattern 9. If the difference in reflectance does not become 10% or more, it is difficult to distinguish both patterns. Therefore, it is preferable that the reflectance is appropriately controlled when the semi-transmissive film 2 or the antireflection film 4 is laminated so as to exhibit a reflectance difference of 10% or more at the inspection wavelength, and a substance having a reflectance of 90% or more. When the semipermeable membrane 2 is laminated, the transmittance is too low to be used as the semipermeable membrane 2.

  Further, the front surface reflectance difference between the antireflection film 4 and the semi-transmissive film 2 is preferably 5 to 70% at the position alignment inspection wavelength. Since the front reflectance can be lowered by the antireflection film 4, it is not a problem when the transflective film 2 is not laminated on the transparent substrate 1. It is difficult to obtain high contrast at the position alignment wavelength of the apparatus, and if the front reflectance is 70% or more, pattern errors due to multiple reflections are likely to occur during the lithography process. Further, when performing the lithography process using the gray tone photomask, there is an advantage that the pattern position alignment described above can be easily and accurately performed because the difference in reflectance on the rear surface is large. Currently, 413 nm is mainly used as the position alignment inspection wavelength, but it is not limited to this because it varies depending on the photomask exposure apparatus. Further, the rear side (Back Side) reflectance of the region where the position alignment pattern is formed is more preferably about 10 to 80% at the position alignment wavelength of the lithography exposure apparatus. This is because when the reflectance is 10% or less at the position alignment wavelength, it is difficult to produce a material having a reflectance of 80% or more because the contrast at the time of the alignment process is low during the lithography process because the contrast is low. is there. The photomask position alignment wavelength of the lithography exposure apparatus mainly uses a wavelength of about 633 nm, but this is not limited to this, and the back surface reflectance should be appropriately controlled by the lithography exposure apparatus. Is preferred.

Moreover, it is preferable to laminate | stack so that the sheet resistance value of the semipermeable membrane 2 may be set to 0-500 kohm / square. When the semi-transmissive film 2 is laminated by the reactive sputtering method described above, a target (Target) having a low surface resistance and a direct current (DC) power source as a power source for discharge are used, and plasma ( (Plasma) is laminated. At this time, if necessary, a reactive gas such as methane (CH ₄ ), oxygen (O ₂ ), nitrogen (N ₂ ), carbon dioxide (CO ₂ ) is used. Since the plasma becomes unstable, defects such as particles are likely to occur. At this time, the sheet resistance of the semi-transmissive film 2 laminated by the reactive gas component also increases. More preferably, particles can be minimized by using methane (CH ₄ ) among the reactive gases described above, and in the structure of the semipermeable membrane according to the amount of gas used, in the film occupied by carbon (C) Only when the ratio is 0.1 at% to 20 at%, the sheet resistance appears low. Therefore, it is preferable to laminate so that the surface resistance of the semi-permeable membrane 2 does not become excessively high, and by adding carbon (C) to the semi-permeable membrane, it can be laminated to be 0 to 500 kΩ / □.

Further, an etching stopper film may be laminated on the upper end of the semi-transmissive film 2. At this time, the etching blocking film plays a role of protecting the semi-transmissive film when etching the light-shielding film and the anti-reflection film, and when etching the light-shielding film and the anti-reflection film in the portion forming the semi-transmissive portion, It is possible to prevent damage such as film reduction of the lower semipermeable membrane. This etching stop film is made of tantalum (Ta), cobalt (Co), 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), silicide (Silicide), molybdenum silicide (MoSi) ), Nickel (Ni), cadmium (Cd), zirconium (Zr), magnesium (Mg), lithium (Li), selenium (Se), copper (Cu), yttrium (Y), sulfur (S), indium tin oxide Made of (ITO), ruthenium (Ru) element alone or an alloy containing two or more It is the can. Note that one or more elements of oxygen (O), nitrogen (N), fluorine (F), chlorine (Cl), hydrogen (H), and carbon (C) may be further included. At this time, it is preferable to be laminated to a thickness of 5 to 300 mm. If the thickness of the etching stopper film is 5 mm or less, a part of the chromium film is removed during etching, and the function as an etching stopper film cannot be sufficiently performed, or it acts as a defect and affects the transmittance. Effect. If the etching stopper film is formed to a thickness of 300 mm or more, the etching time increases, which is not suitable for manufacturing a gray-tone photomask. The etching stopper film is preferably removed in order to minimize the influence on the transmittance of the semi-permeable film, but the transparent film exemplified above has a high transmittance, so that the transmittance of the semi-permeable film is damaged. It may be left as long as it is not. By configuring the etching stopper film on the upper end of the semi-transmissive film, it is possible to manufacture gray-tone photomasks having four different transmittances. Using the above gray-tone blank mask, a light-shielding pattern in which a semi-transmissive film, an etching stopper film, a light-shielding film, and an anti-reflection film are sequentially laminated on a transparent substrate, and a semi-transmissive film and an etching stopper film are sequentially laminated on a transparent substrate. The first semi-transmissive film pattern, the second semi-transmissive film pattern in which the semi-transmissive film is laminated on the transparent substrate, the semi-transmissive film, the etching blocking film, the light shielding film, and the antireflection film are etched to obtain the transparent substrate. It is possible to manufacture a gray-tone photomask composed of an exposed transmission pattern. The etching blocking film functions as a semi-transmissive film. When measuring the reflectance from the light-shielding film and the anti-reflection film to the semi-transmissive film side (front side), or from the semi-transmissive film to the light-shielding film and the anti-reflection film. It may have a function of adjusting the reflectance when measuring the reflectance to the film side (rear surface side). The etching stopper film may have an amorphous structure and a thickness of 10 to 1000 mm.

  In addition, when a gray-tone photomask is manufactured using the gray-tone blank mask, the exposure process is usually performed twice. At this time, a semi-transmissive portion region is formed in the first exposure step, and then a pattern is formed up to the transmissive portion region. In the first exposure step, only the semi-transmissive portion region is formed, and the second exposure is performed. The formation of the transmissive region can be selectively used.

  As described in detail, the gray tone blank mask and photomask of the present invention have the following effects.

  First, a semi-permeable membrane is formed using a reactive gas during the process so that the composition of the semi-permeable membrane is a metal compound and has a high etching rate with respect to the etching solution. The etching rate of the permeable film can be increased, the temperature of the etching solution can be lowered, and the pattern cross section becomes vertical due to the increased etching rate. As a result, CD control of the semi-transmissive film becomes easy, and the etching process becomes unstable. Provide a gray-tone blank mask that can be eliminated.

  Second, by adding one or more selected from carbon, oxygen, nitrogen, chlorine, hydrogen, and fluorine to the composition of the semipermeable membrane, a high etching selectivity can be achieved during wet etching of the semipermeable membrane. Provided is a gray-tone blank mask that can be precisely controlled by preventing surface damage of a semi-transmissive film during wet etching of a light-shielding film and an anti-reflection film.

  Third, when wet or semi-permeable membranes are wet etched, NaOH or KOH can be used alone or in combination to improve process stability, minimize particle generation, and improve etching rate. A gray tone blank mask is provided.

  A fourth and a semi-transparent portion can be formed in a slit pattern, and a gray tone blank mask capable of forming a vertical pattern with a uniform exposure amount to the object to be processed and no CD error.

  Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings. The following examples can be modified in various other forms, and the scope of the present invention is not limited to these examples.

Example 1
In this example, a semipermeable membrane was formed in order to investigate the etching rate and chemical resistance characteristics depending on the carbon content in the semipermeable membrane composition made of tantalum. During the production of the semi-transparent film of the gray tone blank mask according to the present invention, after the transparent substrate is heated at a temperature of 300 ° C. in a sputtering apparatus for uniform film formation, a tantalum target is used on the transparent substrate. A semi-transmissive film was formed at 252 mm with DC sputtering (Sputter) deposition equipment. In this case, the final transmittance of the semi-transmissive film satisfies 40 to 45% in g-Line as an exposure wavelength. At this time, in order to investigate the influence of carbon (C) on the chemical resistance and the etching rate, methane (CH ₄ ) was added to 0, 1, 5, 10, 20, with 98 sccm of argon and 1 sccm of oxygen. 30 sccm was added, the degree of vacuum was 5 mTorr, and the applied power was 1.5 kW.

  Then, in order to evaluate the etching rate, KOH having a concentration of 45% was heated to 50 ° C. to perform an etching rate test, and chemical resistance was evaluated.

  First, in the results of etching rate evaluation using a KOH etching solution, when 1, 5, 10, 20 sccm of methane was added, 1.8, 2.4, 4.2, and 2.1 Å / sec were sufficient, respectively. It was confirmed to have an etching rate. At this time, the etching time was 140, 105, 60, 120 seconds, and the maximum was 140 seconds. On the other hand, when methane is not added at all, it can be seen that the etching rate was 0.3 Å / sec, and it took 840 seconds in total to etch the semipermeable membrane. It can be seen that when methane was added at 30 sccm, the etching rate was 0.9 cm / sec, which took a total of 280 seconds. Due to such a phenomenon, by adding appropriate carbon to the semipermeable membrane, KOH can be easily penetrated by carbon in the bonding structure between Ta, O, and C, which are elements constituting the semipermeable membrane, and the etching rate. It can be seen that is improved. On the other hand, when carbon is not added, etching is hardly performed due to a stable bond between Ta and O, and when 30 sccm of methane is added, a dense bond between Ta and C is generated and the etching rate is reduced. Judged to be.

  KOH has a characteristic of etching a quartz substrate that is a substrate material of a gray-tone blank mask. Therefore, when etching using KOH, the degree of damage of the substrate according to the etching time was examined through surface roughness. First, in the case of a transparent substrate that was not etched, the surface roughness was measured to be 0.9 nmRa. Next, when 1, 5, 10, 20 sccm of methane with an appropriate etching rate was added, the surface roughness was 2.4, 1.8, 1.3, and 1.9 nmRa, respectively. There was no change. On the other hand, when methane was not added or 30 sccm was added, it showed a large change in surface roughness of 5.3 and 3.4 nmRa, respectively. Therefore, it can be seen that the etching rate must be controlled to at least 1 cm / sec.

Next, for evaluation of chemical resistance, sulfuric acid at 85 ° C. temperature (H ₂ SO ₄ : H ₂ O ₂ = 90: 10) and SC-1 at 23 ° C. temperature (NH ₄ OH: H ₂ O ₂ : It was immersed in a cleaning solution of H ₂ O = 1: 1: 5) for 2 hours, and the change in transmittance at 436 nm was evaluated. First, in the sulfuric acid cleaning, when methane was added at 1, 5, 10, 20 sccm, the transmittance changes were 0.83%, 0.68%, 0.65%, and 0.64%, respectively, and there was no problem. In addition, when methane was not added, it was not as good as 1.4%, and when it was 30 sccm, the best result was shown as 0.12%. On the other hand, in SC-1 cleaning, when methane is added at 1, 5, 10, 20, and 30 sccm, the transmittance changes are 0.79%, 0.71%, 0.74%, 0.64%, 0, respectively. There was no problem with .43%, and 2.1% when methane was not added.

  As described above, the gray tone blank mask on which the semi-transmissive film 2 according to the present embodiment is laminated exhibits a high etching rate at a low etching solution temperature and has an excellent chemical resistance. Is very suitable for manufacturing.

(Example 2)
In this example, a semi-permeable film was formed in order to investigate the degree of particle generation due to the use of the semi-permeable film etching solution. In the production of the semi-transmissive film in the gray-tone blank mask according to the present invention, for uniform film formation, the transparent substrate is heated at 300 ° C. in a sputtering apparatus, and then a tantalum target is used on the transparent substrate. A semi-transmissive film was formed in a thickness of 260 mm using an inert gas and CH ₄ gas with a sputter deposition equipment. In this case, the final transmittance of the semi-transmissive film was 42% for G-Line as an exposure wavelength. It was a satisfactory range. At this time, in order to examine the degree of particle generation by the etching solution, the particle generation degree in each of the etching solutions in which 35% NaOH, 45% KOH, 40% NaOH and 45% KOH are mixed is used with the Hitachi GM3000 equipment. Measured.

  First, after preparing each etching liquid by heating to 55 degreeC temperature, the manufactured semipermeable membrane was wet-etched with the spray method. All showed an etching rate of 1 cm / sec or more. In addition, as a result of measuring the number of particles using GM3000, the number of particles 1 um or more in each of 25% NaOH, 35% NaOH, 45% KOH, 6: 4 ratio of 40% NaOH and 45% KOH is 3, It was measured as 8, 1, and 4 and the number in 1 um or less was measured as 53, 78, 4, and 35. From this result, it was confirmed that a large number of particles were detected in the etching solution containing NaOH among the etching solutions, and that many particles were detected in the mixed etching solution. On the other hand, with 45% KOH, it can be seen that the particle generation amount was detected to be absolutely small. From this result, it can be seen that in the case of NaOH, the surface residue is not easily removed after etching, and this is because the Na component deposited on the wall surface of the etching chamber was adsorbed on the mask during etching. It is done.

(Example 3)
In this example, a semi-permeable membrane was formed in order to investigate the transmittance tendency due to the reactive gas during the production of the semi-permeable membrane. At the time of manufacturing the semipermeable membrane, the target was the same as that of Example 1 and Example 2, argon was used as the inert gas at 100 sccm, and the reactive gas was CH ₄ : N ₂ : O ₂ = ₂ sccm: A semi-transmissive film was formed under two conditions of 10 sccm: 3 sccm and CH ₄ : N ₂ : O ₂ = ₂ sccm: 0 sccm: 3 sccm. The thickness after film formation was 240 mm and 250 mm, respectively.

  Then, the transmittance | permeability in the wavelength from 200 nm to 800 nm was measured with N & K 1512RT Analyzer with respect to these two types of films, and the result is shown in FIG. As a result, the transmittance difference between i-Line and g-Line was measured as 8% and 3%, respectively. From this result, it can be seen that the transmittance tendency changes depending on the selection of the reactive gas. When nitrogen gas is included in the composition of the semi-permeable membrane, the transmittance difference between i-Line and g-Line increases, but the nitrogen gas is not contained, and a semi-permeable membrane is produced using only carbon gas and oxygen gas. Then, it turns out that the transmittance | permeability difference in i-Line and g-Line becomes small. This is considered to be due to the fact that nitrogen is contained in the composition of the semi-permeable membrane, thereby changing the density of the membrane, thereby changing the degree of transmittance depending on the wavelength and changing the tendency.

  Next, in order to analyze the component composition, composition analysis was performed with an Auger Electron Spectroscopy (AES) measurement equipment. As a result of preparing and analyzing the same sample as above, the composition ratio of the film containing nitrogen, oxygen, and carbon was analyzed as tantalum: nitrogen: oxygen: carbon = 67 at%: 13 at%: 6 at%: 4 at%, The composition ratio of the film containing oxygen and nitrogen was analyzed as tantalum: oxygen: carbon = 75 at%: 13 at%: 12 at%. From this result, it can be seen that the composition ratio of the semipermeable membrane is determined in proportion to the amount of reactive gas.

Example 4
In this example, a semipermeable membrane was prepared in order to grasp the etching rate of the mixed solution during wet etching of the semipermeable membrane. The etching solution was mixed by a method of 45% NaOH, 45% KOH, 20% NaOH + 45% KOH, 40% NaOH + 45% KOH, 45% NaOH + 20% KOH, 45% NaOH + 40% KOH, and heated to a temperature of 60 ° C. As a result of wet etching of a 250 mm thick semipermeable membrane with these etching solutions, etching rates of 1.6, 1.2, 2.1, 3.4, 3.6, and 4.3 mm / sec were respectively shown. . From this result, it was found that the etching rate was higher when mixed and used than when the etching solution was used alone, and that the effect of NaOH contributed slightly to wet etching compared to KOH. . Further, when the etching rate results are examined by changing the concentration of the etching solutions used in a mixed manner, it can be seen that the etching rate is slightly faster in proportion to the concentration of the etching solution.

(Example 5)
This embodiment relates to a gray-tone photomask manufactured by further stacking an etching stopper film on a semi-transmissive film. Two types of gray-tone photomasks were manufactured by a manufacturing method with or without an etching stopper film formed on the semi-transmissive portion.

  First, the semi-transmissive film was manufactured to a thickness of 250 mm on a transparent substrate using a chromium target and using DC sputtering equipment and nitrogen at 5 sccm in the same manner as in Example 3. As a result of measuring the transmittance after the formation of the semipermeable membrane, it was 44% at a wavelength of 436 nm. Next, an etching stopper film was manufactured to a thickness of 40 mm using a tantalum target. Then, after depositing a light shielding film and an antireflection film with a chromium target, coating and patterning were performed to manufacture a photomask as shown in FIG.

  Subsequently, a semi-permeable membrane was manufactured to a thickness of 220 mm on a transparent substrate using a chromium target. Then, an etching stopper film was manufactured to a thickness of 30 mm using 15 sccm of nitrogen gas. As a result of measuring the transmittance after forming the etching stopper film, it was expressed as 42% at a wavelength of 436 nm. Since this etching stopper film contains a large amount of nitrogen, the transmittance is high, and it is determined that the transmittance of the semi-transmissive portion is not greatly affected, and can be left as it is on the semi-transmissive portion. A light shielding film and an antireflection film were sequentially laminated, and then coated and patterned to produce a photomask as shown in FIG.

  By proposing the two types of structures in this way, it is possible to easily select the structure of the gray-tone photomask. Furthermore, the reactive gas is adjusted, the stacking order is changed, and the like. A gray-tone photomask having a structure can be manufactured.

(Example 6)
This embodiment relates to a gray-tone photomask in which a semi-transmissive portion is formed in a slit pattern. In order to compare the CD error and the pattern form during exposure, a slit pattern composed of a light shielding film and an antireflection film was also manufactured. First, a target similar to that in Example 1 was prepared, a semi-transmissive film was formed on a transparent substrate, a light shielding film and an antireflection film were formed, and a photoresist was applied. By performing exposure, development, and wet etching, a slit pattern was formed as shown in FIG. As a result of exposure to the object to be processed using the manufactured photomask, when the slit pattern is formed with a semi-transmissive film, it is compared with a comparative pattern, that is, a slit mask composed of a light shielding film and an antireflection film slit pattern. There was no CD error and uniform pattern formation was possible. Then, as a result of manufacturing the slit mask as shown in FIGS. 8 and 9 in the same process, a photomask having a uniform exposure amount, no CD error in the object to be processed, and capable of forming a vertical pattern was obtained. .

It is sectional drawing which shows schematically the cross-sectional form of a gray tone photomask. It is sectional drawing which shows schematically the cross-sectional form of a gray tone photomask. 3 is a graph schematically showing an example of a gray-tone blank mask according to the present invention. 1 is a cross-sectional view schematically illustrating an embodiment of a gray-tone photomask according to the present invention. 1 is a cross-sectional view schematically illustrating an embodiment of a gray-tone photomask according to the present invention. It is sectional drawing which shows schematically the pattern form of the gray tone photomask by a prior art. 1 is a cross-sectional view schematically illustrating an embodiment of a gray-tone photomask according to the present invention. 1 is a cross-sectional view schematically illustrating an embodiment of a gray-tone photomask according to the present invention. 1 is a cross-sectional view schematically illustrating an embodiment of a gray-tone photomask according to the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Semi-transmissive film 3 Light-shielding film 4 Antireflection film 5 Photoresist 6 Etching prevention film 7 Light-shielding part pattern 8 Transmission part pattern 9 Semi-transmission part pattern

Claims (27)

A gray tone in which a semi-transmissive film is formed on a transparent substrate , a light-shielding film is formed on the semi-transmissive film, an anti-reflection film is formed on the light-shielding film, and a resist film is formed on the anti-reflection film A blank mask,
The composition of the semi-permeable membrane contains metal, oxygen (O), and 0.1 to 20 at% carbon (C), and the semi-permeable membrane is formed at a wet etching rate of 1 % / sec or more. Features <br/> gray tone blank mask.   In order to minimize damage to the transparent substrate due to the etching process of the semi-transmissive film, an etching stop film that is not etched when the semi-transmissive film is etched is further formed between the transparent substrate and the semi-transmissive film. The gray-tone blank mask according to claim 1. The light shielding film and the antireflection film e etching step etching stop layer which is not etched during the said characterized in that it is further formed between the semi-transmissive film and the light-shielding film, gray tones of claim 1 Blank mask. Before SL translucent film etch stop layer which is not etched during the etching of the further formed between the transparent substrate and the semi-permeable membrane,
Wherein during the etching process of the light-shielding film and the antireflection film in order to prevent damage to the semipermeable membrane, the light-shielding film and the not etched during the etching process of the antireflection film etching stop layer, the shielding and the semipermeable membrane The gray tone blank mask according to claim 1, further formed between the film and the film. 5. The gray tone blank mask according to claim 2, wherein the etch stop layer has a thickness of 5 to 300 mm .   The semi-transmissive film or the etching stopper film includes tantalum (Ta), cobalt (Co), 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), Silicide (Silicide), 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) Characterized in that it is configured to include an alloy containing gray tone blank mask according to any one of claims 1 to 4.   The semi-permeable film or the etching stopper film is a compound further including one or more elements of oxygen (O), nitrogen (N), fluorine (F), chlorine (Cl), and hydrogen (H). The gray-tone blank mask according to claim 6, comprising:   The gray-tone blank mask according to claim 1, wherein a surface resistance of the semi-transmissive film is 0 to 500 kΩ / □. The gray-tone blank mask according to claim 1, wherein a surface roughness of the semipermeable membrane is 1.3 to 2.4 nm RMS.   The gray tone blank mask according to any one of claims 1 to 4, wherein a thickness of the semi-permeable membrane is 10 to 1000 mm.   5. The gray-tone blank mask according to claim 2, wherein a total thickness including the semi-transmissive film and the etching stopper film is 10 to 1000 mm. 6. The semipermeable membrane is
Contains oxygen,
The gray-tone blank mask according to claim 1, wherein a transmittance difference is within 10% at an exposure wavelength of 365 nm to 436 nm. The semipermeable membrane is
Contains nitrogen,
The gray-tone blank mask according to claim 1, wherein a difference in transmittance is 5% or more at an exposure wavelength of 365 nm to 436 nm.   The reflectance difference between the light shielding film or the antireflection film and the front surface (Front Side) of the semi-transmissive film is 5 to 70% at the position alignment inspection wavelength, and 10 to 80% at the position alignment wavelength on the back surface (Back Side). The gray-tone blank mask according to claim 1, wherein The semi-transmissive film has an amorphous structure that is not crystallized, and has a function of adjusting a reflectance with the transparent substrate or a reflectance with the light shielding film. Item 5. The gray-tone blank mask according to any one of Items 1 to 4. Semi-transparent film is formed on a transparent substrate, the semi-permeable membrane selectively shielding on film or antireflection film is formed, in claim 1 in which the resist layer on the light-shielding film or antireflection film is formed A method of manufacturing the described gray-tone blank mask,
The translucent film is formed by reactive sputtering or vacuum deposition (PVD, CVD, ALD, ion beam), and reactive gases such as methane (CH4), acetylene (C2H2), ethylene (C2H4), and propane (C3H8). , Vinylacetylene (C4H4), divinylacetylene (C6H6), butane (C4H10), butylene (C4H8), ethane (C2H6), carbon monoxide (CO), carbon dioxide (CO2) and fluorocarbon (CF4) A method for producing a gray-tone blank mask, which is produced by introducing at least one selected from the above-mentioned. The reactive gas includes nitrogen (N2), oxygen (O2), nitrous oxide (N2O), nitrogen oxide (NO), nitrogen dioxide (NO2), ammonia (NH3), chlorine (Cl2) and fluorine (F). The method for manufacturing a gray-tone blank mask according to claim 16 , further comprising introducing at least one reactive gas selected from the group consisting of 0.1 to 20 vol% . A gray-tone photomask that is patterned into a gray-tone blank mask according to any one of claims 1 to 4 and partially includes a semi-transmissive part region, a transmissive part region, and a light-shielding part region,
The semi-transmissive part region is composed of a semi-permeable film, or is composed of a semi-permeable film and an etching stopper film.
The gray-tone photomask according to claim 1, wherein the transparent region is formed by exposing the transparent substrate or a transparent substrate and an etch stop layer. A gray-tone photomask that is patterned into a gray-tone blank mask according to any one of claims 1 to 4 and partially includes a semi-transmissive part region, a transmissive part region, and a light-shielding part region,
The semi-transmissive part region is a semi-permeable film, or a film composed of any one or more of a semi-permeable film and an etching stopper film, and at the same time, is configured in a slit pattern,
The gray-tone photomask according to claim 1, wherein the transparent region is formed by exposing the transparent substrate or a transparent substrate and an etch stop layer. A method for producing a gray-tone photomask having a pattern of a gray-tone blank mask according to any one of claims 1 to 4 and partially having a semi-transmissive part region, a transmissive part region, and a light-shielding part region,
The semi-transmissive portion region is formed of a semi-transmissive film, or etched with a resist film, an anti-reflective film, and a light-shielding film or an etching preventive film so as to be formed of a semi-transmissive film and an etching stop film. Remove,
The transmissive portion region is formed of a resist film, an antireflection film and a light shielding film or an etching prevention film, a semi-transmission film and an etching prevention film so that the transparent substrate is exposed or is formed of a transparent substrate and an etching prevention film. Etched away
The method of manufacturing a gray-tone photomask, wherein the semi-transmissive film in the transmissive region is removed by performing a wet etching process using an etchant containing NaOH or KOH. The temperature range of the etching solution used when wet-etching the semipermeable membrane in the transmissive region is 23 to 100 ° C.
21. The method of manufacturing a gray-tone photomask according to claim 20 , wherein the etching solution contains 5 to 50% NaOH or KOH. NaOH and KOH solution used in the case of wet etching the semipermeable membrane of the transmissive region is, NaOH: KOH = 1: 9 to 9: characterized in that a mixing ratio of 1, according to claim 20 A method for producing a gray-tone photomask. A method for producing a gray-tone photomask having a pattern of a gray-tone blank mask according to any one of claims 1 to 4 and partially having a semi-transmissive part region, a transmissive part region, and a light-shielding part region,
The semi-transmissive portion region is a film composed of one or more of a semi-transmissive film, a light shielding film, an antireflection film, and an etching blocking film, and at the same time, a resist film so as to be configured in a slit pattern. , Remove the antireflection film or the light shielding film or the semi-transmissive film or the etching stopper film by etching,
The transmissive portion region is formed of a resist film, an antireflection film or a light shielding film or an etching prevention film, a semi-transmissive film or an etching prevention film, so that the transparent substrate is exposed or is composed of a transparent substrate and an etching prevention film. Etched away
The method for manufacturing a gray-tone photomask, wherein the semi-transmissive portion region and the semi-transmissive film in the transmissive portion region are removed by performing a wet etching process using an etchant containing NaOH or KOH. The temperature range of the etching solution used when wet-etching the semipermeable membrane in the transmissive region is 23 to 100 ° C.
The method of manufacturing a gray-tone photomask according to claim 23 , wherein the etching solution contains 5 to 50% NaOH or KOH. NaOH and KOH solution used in the case of wet etching the semipermeable membrane of the transmissive region is, NaOH: KOH = 1: 9 to 9: characterized in that a mixing ratio of 1, according to claim 23 A method for producing a gray-tone photomask. A method for producing a gray-tone photomask having a pattern of a gray-tone blank mask according to any one of claims 1 to 4 and partially having a semi-transmissive part region, a transmissive part region, and a light-shielding part region,
In the process including the first exposure process, a semi-transmissive portion region is formed through removal of the resist film, the antireflection film, the light shielding film, or the etching stopper film,
A method of manufacturing a gray-tone photomask, comprising: forming a transmission region by removing an etching stopper film, a semi-transmissive film, or an etching stopper film in a process including a second exposure process. A method for producing a gray-tone photomask having a pattern of a gray-tone blank mask according to any one of claims 1 to 4 and partially having a semi-transmissive part region, a transmissive part region, and a light-shielding part region,
In a process including the first exposure process, a transmissive part region is formed through removal of a resist film, an antireflection film, a light shielding film, an etching stopper film, a semi-transmissive film, or an etching stopper film,
A method for producing a gray-tone photomask, comprising: forming a translucent region by removing a resist film, an antireflection film, a light shielding film, or an etching stopper film in a process including a second exposure process.

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