KR20080031535A - Gray-tone blank mask and gray-tone photomask, the manufacturing method of them - Google Patents

Abstract

A gray-tone blank mask, a gray-tone photomask, and a manufacturing method thereof are provided to finely manufacture a semi-transparent pattern for improving the quality of an FPD(Flat Panel Display), and to make the minimum linear width of an object identical to or less than 2mum. A gray-tone blank mask, which is a raw material of a gray-tone photomask used in a lithography exposure device using a single wavelength of 365nm or using exposure light of 365nm as a main exposure light source, comprises at least a non-transparent pattern, a semi-transparent pattern, and a transparent pattern on a transparent substrate(1). A semi-transparent layer(2) is deposited on the transparent substrate, and a non-transparent layer(3) is layered thereon.

Description

Gray-tone Blank Mask and Gray-tone Photomask, the Manufacturing method of them}

1 is a cross-sectional view showing a first embodiment of the present invention.

2 is a cross-sectional view showing a second embodiment of the present invention.

<Explanation of symbols for main parts of drawing>

1: transparent substrate 2: semi-permeable membrane

3: shading film 4: anti-reflection film

5: photoresist

The present invention relates to a gray tone used in a mask shortening process in the manufacture of flat panel display (FPD) products such as liquid crystal display (LCD), organic light emitting diode (OLED), plasma display panel (PDP), and electroluminescent display (FED). It relates to a blank mask and a photomask.

Today's flat panel display (FPD) products, such as liquid crystal display (LCD), organic light emitting diode (OLED), plasma display panel (PDP), and electroluminescent display (FED), have a range of application as the market demands are advanced and advanced. As is expanding, the development of excellent manufacturing process technology is required.

In general, a lithography process using a patterned photomask is used to manufacture a flat panel display such as a TFT-LCD. Recently, a technique of using a mask shortening process has been developed and applied for cost reduction and yield improvement.

For example, in the case of a TFT-LCD, a process transition from a conventional 5-mask process to a 4-mask and a 3-mask is gradually performed in manufacturing a TFT substrate. The above mask shortening process is possible by using a mask shortening process photomask that can produce two exposure effects as a single photomask, and it is possible to shorten the process by reducing the number of exposures, improve productivity and yield, and reduce material cost. The cost reduction effect can be obtained.

Since the photomask for the mask shortening process must produce two exposure effects with one exposure, the conventional photomask is composed of a light shielding pattern and a transmission pattern, whereas the mask shortening process photomask has a light shielding pattern, a transmission pattern, and a semi-transmissive pattern. Will be made.

In the mask shortening process, the exposure is performed by the above pattern, and the photoresist of the subject is completely removed by the transmission pattern, the region where the photoresist residual film of the subject remains by the semi-transmissive pattern, and the photoresist of the subject by the shading pattern. Forms a region where the thickness is completely, and first, the region where the photoresist has been completely removed is patterned by etching or the like to obtain an effect by one exposure, and the region where the residual photoresist film remains by ashing or the like. After removing the photoresist, the newly exposed areas are patterned by etching to obtain a second exposure effect. Conventionally, as a photomask for such a mask shortening process, a conventional binary blank mask is used, and a slit mask in which a slit pattern is formed in a semi-transmissive pattern has been generally used. There is a need for a graytone mask using a blank mask and having a semitransmissive layer laminated on a semitransmissive pattern.

However, the gray tone mask has the following problems.

Recently, as flat panel display products are rapidly advanced, the manufacturing process is required to produce finer patterns. In the manufacture of flat panel display products such as TFT-LCD, the lithography process is carried out using broadband light as exposure light. In many cases, it was common to use a 300-500 nm broadband exposure light including a 365 nm i-line, a 405 nm h-line, and a 436 nm g-line of a mercury (Hg) lamp as a light source.

However, since the exposure by the broadband wavelength differs in the degree of diffraction according to each wavelength passing through the transmission pattern and the semi-transmissive pattern due to chromatic aberration, and especially in the case of exposure light transmitting through the semi-transmissive pattern, the resolution is reduced. Due to the pattern size control and the minimum line width (CD) of the subject it was very difficult to manufacture a 2㎛ or less.

In particular, the miniaturization of the transflective pattern, which is most important in the mask shortening process, is difficult, thereby restricting the quality and quality improvement of the flat panel display product and reducing the yield of the mask shortening process.

The present invention has been made to solve the above problems, and an object thereof is to provide a gray tone blank mask, a gray tone photo mask, and a method of manufacturing the same, which can produce a minimum line width of a subject of 2 μm or less.

In addition, the present invention was created in order to solve the above problems, a gray tone blank mask and a gray tone photomask and a method of manufacturing the same that can produce a semi-transparent pattern finely to improve the quality and quality of flat panel display products Its purpose is to provide.

In addition, the present invention was created to solve the above problems, and can be used for a mask shortening process in a lithographic exposure apparatus using the exposure light without chromatic aberration as a light source, and a gray tone photomask and a manufacturing method thereof. To provide that purpose.

In order to achieve the above object, the present invention uses a single wavelength of i-line (365 nm) or does not include characteristic wavelengths of mercury lamps such as h-line (405 nm) and g-line (436 nm). It is preferable to expose using a broadband wavelength including line (365 nm). Chromatic aberration that inhibits the resolution occurs because the diffraction degree when transmitting the transmission pattern (slit) is different according to each wavelength, and the smaller the transmission pattern, the larger. Therefore, when a single wavelength is used instead of the broadband wavelength as the exposure light, the resolution degradation due to the chromatic aberration can be eliminated. In the case of mercury lamps, the intensity of characteristic wavelengths such as i-line, h-line, and g-line is particularly strong. Therefore, even when a broadband wavelength including only one characteristic wavelength is used as exposure light, the intensity of exposure light of the peripheral part of the mercury lamp is increased. Because of their weakness, the effect is almost the same as using a single wavelength. In addition, the resolution decreases at the same time as the exposure wavelength decreases as shown in the following equation. Therefore, to obtain the best resolution, it is preferable to use an i-line of 365 nm, which is a characteristic wavelength having the shortest wavelength among i-line, h-line, and g-line.

R: resolution k1: process constant

NA: numerical aperture λ: exposure wavelength

In addition, in order to achieve the above object, the present invention provides a semi-transmissive film in which a gray tone blank mask, which is a raw material of a gray tone photomask, has a transmittance of 10 to 90% in exposure light having a wavelength of 365 nm on the transparent substrate 1 ( It is preferable that the light shielding film 3 which has a light shielding effect with respect to 2) and the said exposure light is laminated | stacked. If the transmissivity of the semi-transmissive film 2 is 10% or less, shading is performed using the gray tone photomask, so that the thickness of the remaining film of the photoresist 5 of the subject due to the semi-transmissive pattern remains too thick. In contrast to the photoresist 5 pattern due to the pattern, on the contrary, when the transmittance is 90% or more, the thickness of the remaining film of the photoresist 5 of the subject due to the semi-permeable pattern is too thin. 5) It is difficult to distinguish from patterns. Therefore, there is a difficulty in performing a mask shortening process such as 4-mask or 3-mask.

In addition, in order to achieve the above object, in the present invention, it is preferable that the blank mask has a form in which a semi-transmissive film 2 is laminated on at least the transparent substrate 1 and a light shielding film 3 is stacked thereon.

When the blank mask is formed, the semi-transmissive film 2 and the light shielding film 3 may be etched to form a pattern. In addition, since the semi-transmissive film 2 is stacked below the light shielding film 3, the gray tone blank mask preferably has an etching selectivity of 3 or more with respect to the etching solution of the light shielding film 3. If the etch ratio of the semi-permeable membrane 2 to the etching solution 3 is less than or equal to 3, only the light shield is etched to damage the semi-transmissive layer 2 at the time of forming the semi-transmissive pattern, thereby making it difficult to obtain a desired transmittance.

In addition, it is more preferable that the antireflection film 4 is further laminated on the light shielding film 3 to reduce the reflectance in the production of a gray tone photomask and a lithography process. Further stacking of the anti-reflection film 4 prevents standing wave phenomenon during photomask fabrication and reduces pattern errors due to multiple reflections during the lithography process using a gray tone photomask.

In addition, in order to achieve the above object, the present invention preferably manufactures a gray tone photomask using the gray tone blank mask. As a result of the above, the light shielding pattern of the gray tone photomask has at least a semi-transmissive film 2 laminated on the transparent substrate 1 and the light shielding film 3 is laminated thereon, and the semi-transmissive pattern is semi-transmissive on the transparent substrate 1. The film 2 is laminated and the light shielding film 3 is etched and removed, and the transmission pattern is formed by removing the semi-transmissive film 2 and the light shielding film 3 from etching.

In addition, in order to achieve the above object, in the present invention, the gray tone blank mask is preferably in the form of a semi-transmissive film 2 is laminated on the light shielding film 3 pattern formed by etching the light shielding film 3. Since the semi-transmissive layer 2 is stacked on the transparent substrate 1 on which the light-shielding layer 3 is etched, the etch ratio with the light-shielding layer 3 is not limited, and the material having the same etching characteristics is a semi-transmissive layer. (2) It can be used as a substance.

In addition, in order to achieve the above object, the present invention preferably manufactures a gray tone photomask using the gray tone blank mask. As a result of the above, the light shielding pattern of the gray tone photomask is formed by stacking at least the light shielding film 3 on the transparent substrate 1 and then laminating the transflective film 2 thereon. The transflective film 2 is stacked on the transparent substrate 1, and the transmissive pattern is formed by removing the light shielding film 3 and the transflective film 2 by etching.

In addition, in order to achieve the above object, in the present invention, an alignment key pattern is formed to align the pattern position by the primary exposure and the pattern position by the secondary exposure when the semi-transmissive film 2 is laminated. It is preferable not to laminate the semi-transmissive film 2 in some regions including the region to be formed. The alignment key pattern is formed by the first exposure, and the second transmission is not performed because the transflective film 2 is not laminated in the area. Position alignment can be easily and precisely.

In addition, in order to achieve the above object, it is preferable that the present invention exposes one of the first and second exposure patterns larger than the pattern actually formed so as to be self-aligned. The largely exposed pattern serves only as an alignment margin and may be used within a range that does not become an actual pattern.

In addition, in order to achieve the above object, the present invention preferably satisfies a transmittance deviation of 5% or less in i-line (365 nm), h-line (405 nm), and g-line (436 nm). When the semi-transmissive film 2 is laminated and a gray tone photomask is manufactured as described above, a lithographic exposure apparatus using broadband wavelength as exposure light as well as in a lithography exposure apparatus using i-line as exposure light as described above. Even in the same transmittance there is an advantage that can be used.

Moreover, in order to achieve the said objective, in this invention, it is preferable that the transmittance | permeability deviation of the semi-transmissive film 2 becomes 5% or less in the wavelength of 365 nm in the area | region except 50 mm in the outer periphery of a board | substrate. In the mask shortening process using a gray tone photomask, the precision of the second pattern depends on the transmittance precision of the transflective pattern. Therefore, the smaller the transmittance variation of the transflective pattern in the substrate, the better. If the transmittance variation is 5% or more, the process margin is reduced during the mask shortening process and causes a defect. Since the pattern involved in the exposure of the subject is not generally formed at about 50 mm outside of the substrate, the transmittance deviation of the outside of the substrate is irrelevant. Therefore, the transmittance deviation may be within 5% only within an area excluding 50 mm from the outside of the substrate.

In addition, in order to achieve the above object, in the present invention, it is preferable that the reflectance of the front side of the semi-transmissive film 2 is 5 to 70% of the reflectance at the gray tone photomask pattern inspection wavelength. In general, in the process of manufacturing a gray tone photomask using a gray tone blank mask, pattern defects are inspected to clean and repair defects. During the pattern defect inspection, the reflectance of the semi-transmissive layer 2 is examined. If it is less than 5%, there is little difference from the reflectance of the transparent substrate 1, which is a transparent pattern, and thus it is difficult to distinguish it from the transparent pattern. Therefore, a problem of pattern inspection is very difficult, and the reflectance of the semi-transmissive film 2 is increased. When 70% or more is used, the lithographic exposure using the gray tone photomask strongly rereflects the exposure light reflected by the subject, thereby easily causing pattern defects.

More preferably, the reflectance of the semi-transmissive film 2 is 15 to 40%. In the manufacture of FPD, the inspection wavelength is generally about 300 to 600 nm.

In addition, in order to achieve the above object, in the present invention, it is preferable that the difference in reflectance between the semi-transmissive film 2 and the surface of the light shielding film 3 or the anti-reflection film 4 becomes 5 to 60% at the inspection wavelength. As described above, when the pattern inspection is performed in the process of manufacturing the gray tone photomask, when the semi-transmissive pattern has a difference in reflectance between the light shielding film 3 pattern and 5% or less, pattern inspection is difficult. In the case of performing lithography exposure using the light source, the subject tends to cause pattern defects due to the high reflectance of the light shielding pattern or the transflective pattern.

The reflectance difference is more preferably 5 to 20%.

In addition, in order to achieve the above object, the present invention is preferably such that the phase change by the semi-transmissive film 2 is 0 to ± 100 ° at a wavelength of 365 nm.

Since the semi-transmissive film 2 has a refractive index of 1 or more, the exposure light transmitted through the semi-transmissive pattern on which the semi-transmissive film 2 is laminated causes a phase difference as compared with the exposure light transmitted through the transmissive pattern.

At this time, when the semi-transmissive film 2 pattern and the transmission pattern are adjacent to each other, the exposure light interferes with each other due to the phase difference, and thus the intensity of the exposure light of the portion where the exposure light overlaps is changed. Easy to cause

Therefore, the transflective film 2 should be laminated so as not to cause destructive interference, and more preferably 0 to 50 °.

The phase change can be calculated by using a phase shift measuring apparatus such as MPM-100 manufactured by Lasertech, or by measuring the refractive index of the semi-transmissive film 2 by the following equation.

Φ: phase shift n: refractive index of semi-transmissive film 2

d: thickness of semi-transmissive film 2 λ: exposure light wavelength

In addition, in order to achieve the above object, the present invention is preferably laminated so that the surface roughness of the semi-transmissive film 2 is 0.1-5 nm RMS. If the surface roughness of the semi-transmissive film 2 is 5 nm RMS or more, scattering of the transmitted light passing through the semi-transmissive pattern becomes large, which adversely affects the distribution of exposure light passing through the semi-transmissive pattern. It becomes very difficult to control the remaining film thickness and the like of the photoresist 5 of the subject by the transmission pattern.

Therefore, the smaller the roughness of the semi-transmissive film 2 is, the better and the more preferable it is to be laminated so as to be 0.1 to 1.5 nm RMS.

In addition, in order to achieve the above object, it is preferable that the present invention has an amorphous structure in which the semi-permeable membrane 2 consists of short range ordering between atoms. When the surface roughness of the semi-transmissive film 2 is large, the exposure light transmitted through the semi-transmissive pattern is scattered, and it becomes very difficult to control the residual film thickness and the line width CD of the subject photoresist 5.

Since the surface roughness tends to increase when the semi-permeable membrane 2 becomes crystallization (Crystallization), it is preferable that the semi-permeable membrane 2 is amorphous. Also in the case of the light shielding film 3 and the anti-reflection film 4 described below, it is preferable to have an amorphous structure in order to reduce the problems caused by pattern edge roughness and diffuse reflection.

In addition, the present invention, in order to achieve the above object, the tantalum (Ta), cobalt (Co), tungsten (W), molybdenum (Mo), chromium (Cr), vanadium (V), Palladium (Pd), Titanium (Ti), Platinum (Pt), Manganese (Mn), Iron (Fe), Silicon (Si), Nickel (Ni), Cadmium (Cd), Zirconium (Zr), Magnesium (Mg) It is preferable to have at least one of lithium (Li) selenium (Se), copper (Cu), yttrium (Y), sulfur (S), indium (In), tin (Sn), and germanium (Ge) as a main component. More preferably, the material further comprises any one or more of oxygen (O), nitrogen (N), boron (B), fluorine (F), chlorine (Cl), and hydrogen (H).

In addition, in order to achieve the above object, in the present invention, the optical density (O / D: Optical Density) of the light shielding film 3 is preferably 2.0 to 6.0.

Since the light shielding film 3 should have a light shielding effect with respect to exposure light, it is preferable that the transmittance | permeability with respect to exposure light will be 1% or less, and it corresponds to optical density 2.

In addition, if the optical density is too high, the light shielding effect is hardly increased, but only the thickness of the light shielding film 3 is thickened. The optical density is calculated by the following equation.

Optical density = 2-log ₁₀ (transmittance% _{exposure wavelength} )

In addition, in order to achieve the above object, the present invention, any one of the transflective film 2, the antireflection film 4 and the light shielding film 3 is reactive sputtering by introducing an inert gas and a reactive gas in the vacuum chamber (Reactive Sputtering) and vacuum deposition methods (PVD, CVD, ALD) are preferably used, and reactive sputtering is more preferable.

Reactive sputtering method is very suitable for laminating metal thin films with uniform thickness and composition by using targets such as tantalum (Ta) and chromium (Cr) on a large-area substrate, and depending on the reactive gas used, oxygen (O ), Nitrogen (N), carbon (C), boron (B), fluorine (F), chlorine (Cl), hydrogen (H) and the like can be controlled by controlling the properties of the thin film.

In addition, in order to achieve the above object, the present invention, the transparent substrate (1) before the semi-transmissive film (2) laminated or after the semi-transmissive film (2) lamination is carried out for 0 to 60 minutes at a temperature of 80 ~ 800 ℃ desirable.

Through the heat treatment before and after the semi-permeable membrane (2) can be improved, the transmittance characteristics can be improved, and the chemical resistance to chemicals used for cleaning and the like in the manufacture of a gray tone photomask is improved. In the heat treatment, most of the materials are crystallized at a temperature of 800 ° C. or more, so that the surface roughness of the semi-permeable membrane 2 is easily increased, and there is almost no heat treatment effect at a temperature of 80 ° C. or less.

As the heat treatment method, it is possible to use a non-contact method such as infrared, ultraviolet, X-ray irradiation by a lamp under vacuum or atmospheric pressure, or use a contact method such as a hot plate.

In case of heat treatment in vacuum, inert gas such as argon (Ar), helium (He), neon (Ne), krypton (Kr), xenon (Xe), oxygen (O2), nitrogen (N2) It is also possible to use any one or more of carbon dioxide (CO 2), nitrogen dioxide (NO 2), nitrogen oxides (NO), nitrogen dioxide (NO 2), ammonia (NH 3) and fluorine (F 2).

In addition, in order to achieve the above object, the present invention is difficult to selectively etch between the transparent substrate (1) and the light shielding film (3) or semi-transmissive film (2), or between the light shielding film (3) and the semi-transmissive film (2). In this case, it is preferable to further laminate the etch stop layer.

At this time, when the etch stop layer is laminated between the transparent substrate 1 and the light shielding film 3 or the semi-transmissive film 2, the etching ratio of the etch stop film and the transparent substrate 1, the light shielding film 3 or the semi-transmissive film 2 is 3 or more. It is preferable that the etch ratio between the light shielding film 3 and the semi-transmissive film 2 is 3 or more when laminated between the light shielding film 3 and the semi-transmissive film 2.

Etch ratio is calculated by the following equation. As the etch stop material, it is possible to use the materials listed above if the etching ratio is satisfied.

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, as an etchant, CAN (Ceric Amonium Ntrate), hydrochloric acid (HCl), nitric acid (HNO3), FeCl3, acetic acid (CH3COOH), oxalic acid, sodium hydroxide (NaOH), potassium hydroxide ( It is possible to etch with an etchant containing any one or more of KOH). The etchant may be appropriately selected and used in consideration of the kinds of materials constituting the semi-transmissive film 2, the light shielding film 3, and the etch stop film, the stacking and patterning procedures, and the etching solution is heated according to an etching rate and an etching rate. Or it is more preferable to further contain water (H2O) and hydrogen peroxide (H2O2).

In addition, in order to achieve the above object, in the present invention, it is preferable that at least the photoresist 5 is coated on the gray tone blank mask on which the light shielding film 3 and the transflective film 2 are laminated.

The photoresist may be used in any of a positive type and a negative type, and may be appropriately selected depending on the manufacturing process and design needs.

In addition, in order to achieve the above object, the present invention, the light shielding film 3 and the anti-reflection film 4 has a thickness of 100nm to 2500nm, in order to pattern the light shielding film 3, a photoresist 5 having a thickness of 100nm to 2000nm ) Is preferred.

In addition, in order to achieve the above object, the present invention, it is preferable to use any one of the spin coating method, the capillary coating method, the scan and spin coating method for the photoresist (5) It is more preferred to soft bake within the range of 50 to 300 ° C. after coating.

In addition, in order to achieve the above object, the present invention, it is preferable that any one or more of the transflective film 2, the light shielding film 3 is formed of a material capable of wet etching or a material capable of both wet etching and dry etching. More preferably, both the transflective film 2 and the light shielding film 3 are formed of a material capable of wet etching.

In this case, even if a defect occurs in manufacturing the gray tone blank mask or manufacturing the gray tone photo mask using the gray tone blank mask, the transflective film 2 and the light shielding film 3 may be damaged without damaging the expensive transparent substrate 1. Can be removed and reused.

In addition, in order to achieve the above object, the present invention, the photomask manufactured by the above-described gray tone blank mask manufacturing process is not only a TFT-LCD, but also a semiconductor integrated circuit, an organic light emitting device (OLED), a plasma display panel ( PDP), field effect display (FED) and flat panel display (FPD) are preferable.

 (Example 1)

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. 1A to 1E illustrate a gray tone blank mask, a gray tone photo mask, and a method of manufacturing the same according to a first embodiment of the present invention. In this embodiment, a gray tone blank mask and a gray tone photomask for manufacturing a source / drain / channel pattern of a TFT (Thin Film Transistor) used as a switching element in manufacturing a TFT-LCD will be described as an example. The light blocking pattern corresponds to the source / drain pattern and the transflective pattern corresponds to the channel pattern.

Referring to the drawings, a semi-transmissive film 2 is laminated on a transparent substrate 1, a light shielding film 3 is laminated thereon, an antireflection film 4 is laminated thereon, and a primary photoresist 5 is coated thereon. The gray tone blank mask which concerns on a present Example was manufactured (FIG. 1A). As the transparent substrate 1, a transparent substrate 1 having a size of 152 x 152 x 6 mm of quartz glass was used.

In order to show a preferred embodiment, the substrate is a small substrate commonly used in the manufacture of a semiconductor and a fine pattern of TFT-LCD, but generally, a substrate of 330 x 450 x 6 mm to 1200 x 1600 x 13 mm used in manufacturing TFT-LCD. Even when using the same method is applicable.

In this case, a screen was applied to some areas where the alignment pattern was to be formed so that the semi-transmissive film 2 was not laminated, and the light shielding film 3 and the anti-reflection film 4 were stacked in the alignment pattern area.

The semi-transmissive layer 2 uses a molybdenum silicide (MoSi) target having a ratio of 1 mol: 9 mol of molybdenum (Mo) and silicon (Si) and uses a DC power source. Lamination was carried out using a reactive sputtering apparatus. A semi-permeable membrane 2 of molybdenum silicide nitride (MoSiN) was laminated using 100 sccm of argon (Ar) gas as an inert gas and 15 sccm of nitrogen (N2) gas as a reactive gas.

At this time, the applied power was 0.5 kW and laminated under a pressure of 2 mTorr. The semi-permeable membrane 2 is laminated by controlling the amount of argon (Ar) gas and nitrogen (N2) gas and the power of the sputtering device so that the transmittance is 25% at 365 nm and the thickness is 30 nm. The transmittance suitable for forming source / drain and channel patterns, and the thickness of 30 nm is controlled so that the phase difference of the transflective film 2 is less than 50 ° at 25% transmittance.

The phase difference was 43 ° phase change was measured by the phase shift measuring device MPM-100.

In addition, the surface roughness of the semi-permeable membrane (2) was measured by AFM (Atomic Force Microscope). As a result, it was measured by 0.61 nm RMS, and there was no problem in surface roughness. As a result of XRD (X-Ray Diffraction) analysis, The peak of (Peak) was not found, it was confirmed that the semi-permeable membrane (2) is amorphous.

Then, the light shielding film 3 and the antireflection film 4 were laminated by a method of manufacturing a conventional binary blank mask using the reactive sputtering apparatus. The light shielding film 3 is laminated using a chromium (Cr) target, argon (Ar), nitrogen (N2), and methane (CH4) gas, and the antireflection film 4 is a chromium (Cr) target, argon (Ar), and nitrogen. It laminated using (N2) and carbon dioxide (CO2) gas.

Then, IP3500, a positive type photoresist 5, was coated to a thickness of 465 nm to complete a gray tone blank mask according to this embodiment (FIG. 1A).

Then, a gray tone photomask is manufactured by using the gray tone blank mask. First, exposure and development are performed to form a primary photoresist 5 pattern (FIG. 1B), and then the primary photoresist 5 pattern. As an etching mask, the antireflection film 4 and the light shielding film 3 were etched, and then the semi-transmissive film 2 was etched (FIG. 1C).

ICP dry etching apparatus using anti-reflection film (4) and light-shielding film (3) for chromium etching using chlorine (Cl2) gas and oxygen (O2) gas, and semi-transmissive film (2) using CF4 and SF6 gas It was etched using.

In this case, when the semi-permeable membrane 2 is a wet etching material, for example, tantalum nitride (TaN), the antireflection film 4 and the light shielding film 3 use CR-7S, which is a chromium etchant. It is also possible to prepare only by wet etching using a mixture of heated sodium hydroxide (NaOH) and hydrogen peroxide (H 2 O 2).

As a result of this, a transmission pattern is formed and a light blocking pattern including a transflective pattern is formed. Then, the primary photoresist 5 was removed and the secondary photoresist 5 was coated, followed by secondary exposure and development (FIG. 1D).

The secondary exposure exposes the anti-reflective film 4 and the light shielding film 3 of the transflective pattern to be etched, and then etches the light shielding film 3 with CR-7S using the second photoresist 5 pattern as an etching mask. When the surface of the semi-transmissive film 2 is exposed, the light-shielding pattern including the semi-transmissive pattern is formed by sequentially stacking the light-transmitting film 3 and the anti-reflection film 4 on the transparent substrate 1. The light shielding pattern is divided into a semi-transmissive pattern in which a semi-transmissive layer 2 is laminated on the transparent substrate 1.

Then, when the secondary photoresist 5 is removed, the gray tone photomask according to the present embodiment is manufactured (Fig. 1E). In the present embodiment, first, the light shielding film 3 and the semi-transmissive film 2 are etched by the primary exposure to form the transmission pattern first, and the light shielding pattern and the semi-transmissive pattern are formed by the secondary exposure, but the manufacturing may be performed in reverse order. It is possible to produce the same gray tone photomask by any of the above methods.

That is, forming the transmissive pattern by first etching the light shielding film 3 by the primary exposure and then etching the light shielding film 3 and the semitransmissive film 2 by the secondary exposure to form the transmission pattern and the light shielding pattern. It is possible.

In the present embodiment, in order to accurately align the pattern by the first exposure and the pattern by the second exposure, the exposure is larger than the area of the actual semi-transmissive pattern during the second exposure so as to be self-aligned. The core contents of the patent have been omitted, and cleaning and defect correction processes have also been performed, but the description of the contents has been omitted.

When the transmittance of the prepared gray tone photomask was measured, it was measured as 25.3% at 365 nm, and it was confirmed that there is little damage of the semi-transmissive film 2 in the process of manufacturing the gray tone photomask.

Then, the gray tone photomask manufactured according to the present embodiment was mounted on a lithographic exposure apparatus for manufacturing a TFT-LCD with i-line as exposure light, and evaluation was carried out. ) Patterns have been manufactured with great precision, enabling the formation of fine patterns that cannot be manufactured with conventional lithographic exposure apparatus and gray tone photomasks.

In addition, a more advanced TFT-LCD was manufactured due to the manufacture of the fine pattern, and the defect reduction rate was very low because the mask shortening process was performed smoothly. In addition, it was confirmed that there was no abnormality in the subject pattern at the interface between the transflective pattern and the transmissive pattern, and thus there was no problem due to the phase change of the transflective film 2.

(Example 2)

2A to 2E illustrate a gray tone blank mask, a gray tone photo mask, and a manufacturing method thereof according to a second embodiment of the present invention.

In this embodiment, a gray tone photomask having the same pattern as that of the first embodiment is manufactured, but the gray tone blank mask and the manufacturing method are different.

The process of laminating and etching the light shielding film 3, coating the photoresist 5, exposing and developing were performed in the same manner as in the first embodiment.

First, a light shielding film 3 of chromium carbide nitride (CrCN) was laminated on the transparent substrate 1. The photoresist 5 was then coated to produce a blank mask (FIG. 2A).

After that, the light-shielding film 3 in the region where the semi-transmissive pattern is to be formed is first exposed and developed to form a first photoresist 5 pattern, and then the light-shielding film is formed using the first photoresist 5 pattern as an etching mask. (3) was etched.

The primary photoresist 5 was then removed (FIG. 2B). Then, the semi-transmissive film 2 is laminated on the entire surface except for the region where the alignment pattern is to be formed in the same manner as in the first embodiment. The semi-permeable membrane 2 laminated chromium nitride (CrN) differently from the above. Using the reactive sputtering apparatus described above, an argon (Ar) gas 80 sccm and a nitrogen (N 2) gas 3 sccm were applied to a chromium (Cr) target, and a DC power of 0.35 kW was applied at a pressure of 2 mTorr, and the thickness was laminated to 12 nm.

The transmittance of the semi-transmissive film 2 is 25.1% at 365 nm, 25.3% at 405 nm, and 25.5% at 436 nm, and not only a lithographic exposure apparatus using i-line (365 nm) as exposure light but also a broadband wavelength of 300 to 500 nm. It was produced so that it could be used also in the lithographic exposure apparatus made into optical light.

The phase shift of the semi-permeable membrane 2 was measured at 21 ° and the surface roughness was measured at 0.58 nm RMS, and as described above, the amorphous structure was measured.

Then, the secondary photoresist 5 was coated (FIG. 2C), and then the secondary light exposure and development were performed by preventing the light shielding pattern and the transflective pattern from being etched.

Then, the semitransmissive film 2 and the light shielding film 3 were simultaneously etched using CR7-S. Unlike the first embodiment, since the light shielding film 3 of the present embodiment is chromium carbide nitride (CrCN) and the semi-transmissive film 2 is chromium nitride (CrN), it can be simultaneously etched.

As a result, the light shielding pattern in which the light shielding film 3 and the transflective film 2 are laminated on the transparent substrate 1, the transmission pattern in which the transflective film 2 is laminated on the transparent substrate 1, and the light shielding film ( A gray tone photomask consisting of 3) and a transmissive pattern in which the transflective film 2 was etched and removed was produced. The transmittance of the gray tone photomask of the present embodiment was measured to be 25.5% at 365 nm, 25.7% at 405 nm, and 25.9% at 436 nm, indicating little change in transmittance.

In this embodiment, it is possible to manufacture by changing the order of pattern formation, and it is possible to manufacture the pattern exposure size larger than the actual pattern by adding an alignment margin for self-alignment.

Similarly to the first embodiment, the gray tone photomask manufactured according to the present embodiment was mounted on a lithographic exposure apparatus for manufacturing a TFT-LCD whose i-line is exposure light, and the evaluation was performed. The permeable membrane 2 pattern was produced very precisely.

As described above, the gray tone blank mask and the gray tone photo mask of the present invention provide the following effects.

First, there is an effect of providing a gray tone blank mask and a gray tone photomask, and a method of manufacturing the subject, which can manufacture a subject to 2 μm or less.

Second, there is an effect of providing a gray tone blank mask and a gray tone photomask and a method of manufacturing the same to produce a semi-transparent pattern finely to achieve high quality and quality improvement of flat panel display products.

Third, there is an effect of providing a gray tone blank mask and a gray tone photomask which can be used for a mask shortening process in a lithography exposure apparatus using the i-line without chromatic aberration as a light source.

Although the present invention has been described with reference to a source / drain / channel pattern of TFT-LCD manufacturing as an example, it is not limited thereto, and it is a passivation / contact hole pattern of TFT manufacturing, OLED manufacturing, PDP manufacturing, It is possible to modify suitably according to a manufactured product, a use, an objective, and a pattern form, such as for FED manufacture. Therefore, it is to be understood that the invention is capable of many more modifications and variations within the scope of the following claims.

Claims (24)

Raw material of a gray tone photomask used in a lithographic exposure apparatus having at least a light shielding pattern, a transflective pattern and a transmission pattern on a transparent substrate and using a single wavelength of 365 nm or using 365 nm exposure light as the main exposure light. In the gray tone blank mask, And a semi-transmissive film is laminated on at least the transparent substrate, and a light shielding film is laminated on the blank mask. The method of claim 1, And the etch selectivity of the semi-transmissive film and the light shielding film with respect to the light shielding film etching solution is 3 or more. Raw material of a gray tone photomask used in a lithographic exposure apparatus having at least a light shielding pattern, a transflective pattern and a transmission pattern on a transparent substrate and using a single wavelength of 365 nm or using 365 nm exposure light as the main exposure light. In the gray tone blank mask, And a semi-transmissive layer is laminated on the light blocking layer pattern formed by etching the light blocking layer. The method according to any one of claims 1 to 3, And the transflective film has a transmittance of 10 to 90% in exposure light having a wavelength of 365 nm, and the light shielding film has a light shielding effect with respect to the exposure light. The method according to any one of claims 1 to 3, The semi-transmissive layer is not laminated in at least some of the regions including the alignment pattern required for the second exposure and does not include the region in which the semi-transmissive pattern is formed, and the light shielding film is laminated in at least the region in which the semi-transmissive pattern is formed. And a light shielding film are laminated. The method according to any one of claims 1 to 3, And said transflective film satisfies a transmittance deviation of 5% or less in i-line (365 nm), h-line (405 nm), and g-line (436 nm). The method according to any one of claims 1 to 3, The gray tone blank mask, characterized in that further stacked on the light-shielding film. The method according to any one of claims 1 to 3, A gray tone blank mask, characterized in that the reflectance of the front side of the semi-transmissive film is a reflectance of 5 to 70% at the wavelength of the gray tone photomask pattern inspection. The method according to any one of claims 1 to 3, And a difference in reflectance between the semi-transmissive layer and the surface of the light-shielding layer or the anti-reflection layer is 5 to 60% at a wavelength of the photomask pattern inspection. The method according to any one of claims 1 to 3, The phase change by the semi-transmissive film is gray tone blank mask, characterized in that 0 ~ ± 100 ° at 365nm wavelength. The method according to any one of claims 1 to 3, The gray tone blank mask, characterized in that the semi-transmissive film is laminated so that the surface roughness of 0.1 ~ 5nm RMS. The method according to any one of claims 1 to 3, And said transflective film has an amorphous structure. The method according to any one of claims 1 to 3, Semi-transmissive film is tantalum (Ta), cobalt (Co), tungsten (W), molybdenum (Mo), chromium (Cr), vanadium (V), palladium (Pd), titanium (Ti), flat titanium (Pt), manganese (Mn), iron (Fe), silicon (Si), nickel (Ni), cadmium (Cd), zirconium (Zr), magnesium (Mg), lithium (Li) selenium (Se), copper (Cu), yttrium ( A gray tone blank mask comprising at least one of Y), sulfur (S), indium (In), tin (Sn), and germanium (Ge) as main components. The method of claim 13, The semi-permeable membrane is composed of a material further containing any one or more of oxygen (O), nitrogen (N), boron (B), fluorine (F), chlorine (Cl), and hydrogen (H) components in addition to the main component. Characteristic gray tone blank mask. The method according to any one of claims 1 to 3, And the semi-transmissive film is manufactured using reactive sputtering or vacuum deposition methods (PVD, CVD, ALD). The method according to any one of claims 1 to 3, The transparent substrate is a gray tone blank mask, characterized in that the manufacturing method comprising the heat treatment before or after the semi-transmissive film laminated or translucent film 10 laminated at 0 to 60 minutes at a temperature of 80 ~ 800 ℃. The method according to any one of claims 1 to 3, A gray tone blank mask, wherein an etch stop layer is further laminated on a transparent substrate or a light shielding film or a transflective film. The method according to any one of claims 1 to 3, The gray tone blank mask, characterized in that the photoresist is further coated on the gray tone blank mask. The method according to any one of claims 1 to 3, At least one of the transflective film and the light shielding film is laminated with a material capable of wet etching or a material capable of both wet etching and dry etching. In a gray tone photomask used in a lithographic exposure apparatus having at least a light shielding pattern, a transflective pattern and a transmission pattern on a transparent substrate and using a single wavelength of 365 nm or using 365 nm exposure light as the main exposure light. , The light shielding pattern is at least a semi-transmissive film is laminated on a transparent substrate and the light-shielding film is laminated on the transparent substrate, the semi-transmissive pattern is at least a semi-transmissive film is laminated on a transparent substrate, the transmission pattern is the semi-transmissive film and the light shielding film by etching A gray tone photomask, characterized in that removed to reveal a transparent substrate. In a gray tone photomask used in a lithographic exposure apparatus having at least a light shielding pattern, a transflective pattern and a transmission pattern on a transparent substrate and using a single wavelength of 365 nm or using 365 nm exposure light as the main exposure light. , The light shielding pattern is at least a light shielding film layer is laminated on a transparent substrate and a semi-transmissive film is stacked thereon, the transflective pattern is at least a semi-transmissive film is laminated on a transparent substrate, the transmission pattern is the light shielding film and the semi-transmissive film is removed by etching A gray tone photomask, wherein the transparent substrate is exposed. The method according to any one of claims 20 or 21, The semi-permeable membrane is an etching solution containing any one or more of CAN (Ceric Amonium Ntrate), hydrochloric acid (HCl), nitric acid (HNO3), FeCl3, acetic acid (CH3COOH), oxalic acid, sodium hydroxide (NaOH), potassium hydroxide (KOH) A gray tone photomask, which is prepared by etching. The method according to any one of claims 20 or 21, And the gray tone photomask is for manufacturing a TFT-LCD, an organic light emitting diode (OLED), a plasma display panel (PDP), a field effect display (FED), and a flat panel display (FPD). A flat panel display product produced by using the gray tone photomask according to any one of claims 20 and 21.

Images