TWI505325B - Method of manufacturing a multi-tone photomask and etching device - Google Patents

Description

Multi-step mask manufacturing method and etching device

The present invention relates to a method for manufacturing a multi-step mask for use in manufacturing an FPD (flat panel display) device such as a liquid crystal display (hereinafter referred to as LCD), a plasma display, or an organic EL display, and An etching apparatus used in the method of manufacturing the multi-step mask.

Now, in the field of FPD, and in the field of LCDs, thin film transistor liquid crystal display (hereinafter referred to as TFT-LCD) has the advantages of being easy to be thinner and consumes less power, so it is now rapidly increasing. Commoditized. The TFT-LCD has a TFT substrate (a structure in which TFTs are arranged in a matrix arranged in a matrix) and a color filter (a red, green, and blue pixel pattern is arranged corresponding to each pixel) to interpose a liquid crystal. A schematic structure in which the phases overlap. In the case of a TFT-LCD, the number of processes is large, and it is necessary to use 5 to 6 photomasks for manufacturing a TFT substrate. Under such circumstances, there has been proposed a method of manufacturing a TFT substrate using fewer masks.

This method reduces the number of masks used by using a photomask having a light shielding portion and a light transmitting portion and a semi-light transmitting portion. Here, the semi-transmissive portion means that when the pattern is transferred to the object to be transferred by using a mask, the amount of penetration of the penetrating exposure light is reduced by a predetermined amount to control the light resistance on the object to be transferred. A portion of the film having the semi-transmissive portion, the light-shielding portion, and the light-transmitting portion in the portion of the film after the development of the film is generally referred to as a gray scale mask. By using a semi-transmissive portion having a predetermined exposure light transmittance and a gray-scale mask of the light-shielding portion and the light-transmitting portion, a desired transfer pattern can be formed on the photoresist on the transferred body (including the third-order tone). The residual film value is different). Further, by using a plurality of semi-transmissive portions having different exposure light transmittances and a gray-scale mask of the light-shielding portion and the light-transmitting portion, a plurality of transfer patterns of four or more-order modulations can be further formed. These gray scale masks are referred to as "multi-level masks" in the present invention.

On the other hand, the multi-tone mask is known to have a structure in which the semi-transmissive portion is formed by a fine pattern having a resolution limit of or less than an exposure machine using a multi-step mask. The resolution limit of an exposure machine using a multi-tone mask is about 3 μm in the case of a stepper type exposure machine in most cases, and about 4 μm in a mirror projection type exposure machine. However, in order to design such a semi-transmissive portion of the fine pattern type, it is necessary to select a fine pattern having an intermediate halftone effect of the light shielding portion and the light transmission portion as a line-spacing type, a dot (mesh point). Type, or other pattern. Furthermore, in the case of the line-spacing type, how should the line width be set, how the ratio of the light-transmitting portion to the portion that is shielded from light should be adjusted, and how much the transmittance of the semi-transmissive portion should be designed, and must be considered. There are many factors to design. In addition, even in the manufacture of a mask, a very difficult production technique such as management of a line center value and management of variation of a line width inside a mask is required.

Therefore, it has been proposed to form a semi-transmissive portion with a semi-transmissive film that is semi-transmissive. Exposure can be performed by reducing the amount of exposure in the semi-transmissive portion by using such a semi-transmissive film. In the case of using a semi-transparent film, it is necessary to review the degree of penetration of the whole in the design, and to select the film thickness (the material) of the semi-transparent film to select the film thickness to produce the mask. . Therefore, it is sufficient to control the film thickness of the semi-transmissive film in the manufacture of the multi-step mask, and the relative management becomes easy. Further, for example, in the case where the channel portion of the TFT is formed by the semi-transmissive portion of the multi-step mask, since the semi-transmissive film can be easily patterned by the photolithography process, even the shape of the reticular pattern is obtained. The TFT channel portion can also perform pattern formation with high precision, which is an advantage.

When the semi-transmissive portion of the multi-step mask is formed of a semi-transmissive film, a semi-transmissive film material is widely known as a metal halide such as molybdenum. In addition, a semi-transmissive film material other than a metal halide has been proposed as a material containing ruthenium as a main component (Patent Document 1: JP-A-2008-249950, Patent Document 2: JP-A-2002-- Bulletin No. 196473). In particular, the advantages of materials based on ruthenium include: adjustment of exposure light transmittance can be easily achieved by adjustment of film thickness, and ultra-high pressure mercury lamp which can be widely used in exposure machines for FPD as a light source The exposure wavelength band of the multi-color exposure, that is, the wavelength change across the i-line to the g-line, reduces the change in transmittance with respect to the wavelength (low wavelength dependency and flat spectral characteristics).

The multi-step mask is manufactured by, for example, using a semi-transparent film (a material mainly composed of metal telluride or yttrium) and a light-shielding film (for chrome) on a light-transmissive substrate such as synthetic quartz glass. a mask blank composed of a material of a main component, and the light shielding film and the semi-transmissive film are patterned as desired to form a light shielding portion, a light transmitting portion, and a semi-light transmitting portion. Transfer pattern.

The method for manufacturing the multi-step mask has a process in which a photoresist film having a pattern of a light-transmitting portion formed on a light-shielding film of the mask blank is used as a mask, and the light-shielding film is etched a process of forming a light-transmitting portion pattern by the light-shielding film; and a process of forming the light-transmitting portion by etching the semi-transmissive film by using the light-transmitting portion pattern formed by the light-shielding film as a mask And a process in which the light-shielding film having the light-shielding portion pattern formed on the light-shielding film is used as a mask, and the light-shielding film is etched to form the light-shielding portion pattern on the light-shielding film.

The above etching process can be performed by so-called wet etching or dry etching. However, in recent years, with the increase in the size of the FPD element, the multi-step mask used in the manufacture of the FPD element has also been moving toward an increase in the size of the substrate, which causes the following problems. That is, when dry etching is performed, plasma is generated, and thus the plasma generating apparatus used must be capable of generating electricity for the main surface of the large mask blank (which is very large compared to the LSI application). The slurry has to be introduced into a very expensive dry etching apparatus. Therefore, if the production cost is considered, the dry etching method does not meet the actual demand.

On the other hand, if wet etching is used, such a problem does not occur. An etching solution containing cerium ammonium nitrate and perchloric acid is usually used as a light shielding film etching liquid composed of a material containing chromium as a main component. Further, as the semi-transmissive film etching liquid composed of a material containing a metal halide as a main component, for example, an etching solution containing ammonium hydrogen fluoride and hydrogen peroxide is used. Further, a semi-transmissive film etching liquid composed of a material containing ruthenium as a main component is an alkaline aqueous solution such as sodium hydroxide or potassium hydroxide heated to 50 ° C or higher.

According to the review by the present inventors, in the case of a semi-transparent film composed of a material containing ruthenium as a main component, since the etching rate to the alkaline aqueous solution is not high, the above-mentioned half is removed by wet etching using an alkaline aqueous solution. In the light-transmissive film, it was found that a concave-shaped recess was formed on the surface of the exposed glass substrate, and a serious problem occurred in the multi-step mask.

In order to form the light-transmitting portion of the multi-step mask by wet etching in which the surface of the glass substrate is exposed, the groove ratio is greatly reduced when a concave portion is formed on the surface of the glass substrate constituting the light-transmitting portion. Since the etching difficulty varies depending on the etching difficulty of the pattern shape of the etched semi-transmissive film, it is difficult to suppress the occurrence of the pit-shaped recess even if the etching time is strictly adjusted. When such a multi-step mask is used for the exposure transfer of the pattern of the photoresist film of the transfer target, the problem of the controllability of the residual film amount after the development of the photoresist film is lowered.

On the other hand, in the case of a semi-transmissive film composed of a material containing a metal telluride as a main component, there is no problem that a pit-like recess appears on the surface of the glass substrate. However, as the pattern formed by the semi-transmissive film is made finer, the coarse difference in the surface of the photoresist pattern and the light-shielding film pattern becomes larger. In the etching of the semi-transmissive film, the etchant is easily replaced in the loose pattern portion, so that the etching rate tends to be faster, and the etchant is less likely to be replaced in the dense pattern portion, so that the etching rate tends to be slow. This difference can have a significant effect on the in-plane uniformity of the CD of the semi-transmissive film pattern after etching. In particular, in the case of wet etching, in a dense pattern, the etching liquid is not well replaced compared to the dry etching etching gas, and the in-plane uniformity of the semi-transmissive film tends to be lowered.

On the other hand, in the case of a metal material suitable for a semi-transmissive film of a multi-step mask, in addition to germanium, conventionally, for Hf, zirconium, tungsten (W), zinc (Zn), Molybdenum (Mo), titanium (Ti), vanadium (V), yttrium (Y), yttrium (Rh), niobium (Nb), lanthanum (La), palladium (Pd), iron (Fe), aluminum (Al),锗 (Ge), tin (Sn), etc. were reviewed. An alkaline aqueous solution or the like is examined in terms of an etching solution for wet etching the semi-transmissive film of the metal material. However, similarly to the case of ruthenium, it is difficult to obtain sufficient etching selectivity between the light-transmitting substrates. In addition, it is difficult to say that the in-plane uniformity of the semi-transmissive film is a good problem.

In recent years, the low price competition of FPD components is severe. On the other hand, reducing the manufacturing cost of multi-level masks is also an important issue. In this context, when a multi-step mask made of a mask blank is used to find a pattern defect that is difficult to correct, it is desirable to have to directly discard the multi-level mask as a defective product. A method of peeling off a film from a substrate to regenerate the substrate.

In order to completely remove the damage occurring on the surface of the substrate to regenerate the substrate, it is necessary to perform re-polishing, and it is necessary to spend a lot of polishing removal. The surface polishing of the glass substrate before film formation is usually carried out from a coarse grinding process to a precision grinding process in a plurality of stages. In the case of re-grinding, since it is necessary to spend a large amount of grinding and removing costs as described above, it is necessary to return to the initial stage in the grinding process of the plurality of stages, and the grinding process takes a long time, so that the process burden of re-grinding becomes large, and the cost is increased. Becomes high. That is, a multi-step mask is manufactured by a manufacturing method including the above-described process (wet etching using an alkaline aqueous solution for a semi-transmissive film composed of a material containing ruthenium as a main component), in order to avoid When the mask is found to have a pattern defect that is difficult to be corrected, the mask is directly discarded as a defective product, and the light shielding film and the semi-transmissive film are peeled off from the substrate by the etching liquid and the substrate is regenerated. Cost.

Further, even in the case of reproducing a substrate from a multi-step mask having a semi-transmissive film composed of a material mainly composed of metal and tantalum, the flatness of the substrate peeled off by the etching liquid is inevitably deteriorated. In order to perform the flatness correction, it takes a lot of grinding and removal costs, which is costly in the case of regenerating the substrate.

The present invention has been made in view of the various problems of the prior art, and its object is to provide a method for manufacturing a multi-step mask, which does not require a very expensive dry etching apparatus, when forming a pattern on a semi-transparent film. The in-plane uniformity of the CD is higher than that of the wet etching, and the regeneration cost of the substrate can be reduced by reducing the regrind process burden when the substrate is regenerated, especially in the case of a semi-transparent film mainly composed of germanium. It is possible to suppress the occurrence of pit-like recesses on the surface of the substrate during the mask manufacturing stage; and the present invention provides an etching apparatus used in the method of manufacturing the multi-step mask.

In order to solve the above problems, the inventors of the present invention have found that a material containing a metal or a ruthenium or a material selected from the group consisting of tantalum (Ta), hafnium (Hf), zirconium (Zr), tungsten (W), and zinc (Zn) has been found. ), molybdenum (Mo), titanium (Ti), vanadium (V), yttrium (Y), yttrium (Rh), niobium (Nb), lanthanum (La), palladium (Pd), iron (Fe), aluminum (Al ), when a semi-transmissive film made of a material of one or more kinds of metals in germanium (Ge) and tin (Sn) is etched, by using a specific fluorine-based compound, that is, chlorine (Cl) or bromine (Br) a non-excited state substance of a compound of any one of iodine (I) and ruthenium (Xe) and fluorine (F) (hereinafter also referred to as "the fluorine compound of the present invention"), compared to wet etching In this case, the in-plane uniformity of the CD in the semi-transmissive film pattern after etching can be improved. In particular, in the case of etching a semi-transmissive film composed of a material containing ruthenium, by using a non-excited state substance containing the fluorine-based compound of the present invention, the surface of the substrate after removing the semi-transparent film by etching can be suppressed. A pit-like concave defect occurs.

The present inventors have completed the present invention based on the above-described explanation of the facts and further efforts to continuously study the results.

That is, in order to solve the above problems, the present invention has the following aspects.

(Figure 1)

A multi-step mask manufacturing method for manufacturing a transfer pattern comprising a light-shielding portion, a light-transmitting portion, and a semi-transmissive portion penetrating a portion of the light-exposure light on the light-transmitting substrate a multi-tone mask; characterized in that it has a process of sequentially laminating a material containing metal and tantalum on a light-transmitting substrate or containing a material selected from the group consisting of tantalum (Ta), hafnium (Hf), and zirconium (Zr). ), tungsten (W), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium (V), yttrium (Y), yttrium (Rh), niobium (Nb), lanthanum (La), palladium (Pd) a semi-transmissive film composed of a material of one or more kinds of metals such as iron (Fe), aluminum (Al), germanium (Ge), and tin (Sn), and a light-shielding film composed of a material containing chromium (Cr) a process of masking the blank material; forming a light-transmitting portion pattern in the light-shielding film; forming a light-transmitting portion pattern formed by the light-shielding film as a mask, and the semi-transmissive film comprises chlorine (Cl) and bromine a process of etching (Br), an element of any one of iodine (I) and xenon (Xe) and a non-excited state of a compound of fluorine (F); and forming a light-shielding pattern on the light-shielding film Process.

(Figure 2)

The manufacturing method of the multi-tone mask of the aspect 1, wherein the process of forming the light-transmitting portion pattern in the light-shielding film is covered by the photoresist film having the light-transmitting portion pattern formed on the light-shielding film The mask is wet etched.

(Figure 3)

A multi-step mask manufacturing method for manufacturing a transfer pattern comprising a light-shielding portion, a light-transmitting portion, and a semi-transmissive portion penetrating a portion of the light-exposure light on the light-transmitting substrate a multi-tone mask; characterized in that it has a process of sequentially laminating a material containing metal and tantalum on a light-transmitting substrate or containing a material selected from the group consisting of tantalum (Ta), hafnium (Hf), and zirconium (Zr). ), tungsten (W), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium (V), yttrium (Y), yttrium (Rh), niobium (Nb), lanthanum (La), palladium (Pd) a semi-transmissive film composed of a material of one or more kinds of metals such as iron (Fe), aluminum (Al), germanium (Ge), and tin (Sn), and a light-shielding film composed of a material containing chromium (Cr) a process for forming a blank material; a process for forming a light shielding portion pattern on the light shielding film; a process for forming a photoresist film having a light transmitting portion pattern on the light shielding film and the semi-transmissive film; and forming the photoresist film The light transmissive portion pattern is a mask, and the semi-transmissive film is formed by containing an element of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) and fluorine (F). The non-excited state of the compound is etched Cheng.

(Figure 4)

The manufacturing method of the multi-tone mask according to any one of the above aspects, wherein the process of forming the light-shielding portion pattern on the light-shielding film is performed by patterning the light-transmitting portion formed on the light-shielding film. The photoresist film is performed by wet etching of a mask.

(Figure 5)

The method of manufacturing a multi-tone mask according to any one of aspects 1 to 4, wherein the non-excited state substance is a ClF ₃ gas.

(Figure 6)

The method of manufacturing a multi-tone mask according to any one of aspects 1 to 5, wherein the metal in the semi-transmissive film is molybdenum (Mo).

(Figure 7)

The method of manufacturing a multi-tone mask according to any one of aspects 1 to 6, wherein the light-shielding film is made of a material further containing nitrogen.

(Figure 8)

The method of manufacturing a multi-tone mask according to any one of the aspects 1 to 7, wherein the light-transmitting substrate is made of synthetic quartz glass.

(Figure 9)

An etching apparatus for use in a method for manufacturing a multi-tone mask of any of the aspects 1 to 8; characterized in that: the chamber has a platform for setting the mask blank; non-excited The material supply device is configured to supply a non-excited state substance to the chamber; and a gas discharge device that discharges gas from the chamber.

According to the manufacturing method of the multi-tone mask of the above-described aspects 1 to 8, the semi-transmissive film has a high etching rate for the non-excited state substance containing the fluorine-based compound of the present invention, and is used as a light-transmitting substrate material. The etching rate of the glass for the non-excited state material is relatively low, so that high etching selectivity can be obtained between the light-transmitting substrate and the semi-transmissive film. Thereby, the semi-transmissive film which is a part of the light-transmitting portion of the multi-step mask is etched and removed by the non-excited state substance to form a multi-step mask, and the CD surface of the semi-transmissive film pattern is uniform. The improvement can be improved compared to the case of wet etching.

In particular, in the case of a semi-transmissive film composed of a material containing germanium, after the semi-transmissive film is removed by etching, pit-shaped concave defects occurring on the surface of the substrate can be suppressed. Thereby, the in-plane uniformity of the light transmittance of the light-transmitting portion can be improved, and the photoresist film can be imaged by transferring the pattern onto the photoresist film of the transfer body using the multi-step mask. The amount of residual film after that can also be controlled with high precision.

Further, since the non-excited state substance is applied for etching, the chamber to be etched can fully function as long as it can reach a certain low voltage. Therefore, a large-sized chamber for high vacuum such as a dry etching apparatus or a large-scale plasma generating apparatus for generating plasma on the main surface of the substrate is no longer required, and the production cost can be greatly reduced. In addition, since a high-quality substrate can be regenerated at low cost, it is particularly suitable for substrate regeneration using a multi-step mask of an expensive substrate (high added value).

Furthermore, the manufacturing method of the multi-tone mask of the above-described modes 1 to 8 can be easily realized by using the etching apparatus of the above-described aspect 9.

Hereinafter, embodiments of the present invention will be described in detail.

Fig. 1 is a schematic cross-sectional view for explaining a pattern transfer method using a multi-tone mask. The multi-tone mask 20 shown in FIG. 1 is used to manufacture a FPD component such as a thin film transistor (TFT), a color filter or a plasma display panel (PDP) of a liquid crystal display (LCD). When the multi-level mask 20 is used to perform pattern transfer on the transfer target 30 shown in FIG. 1, a photoresist pattern 33 having a stepwise or continuous difference in film thickness can be formed. Further, reference numerals 32A and 32B in Fig. 1 are shown on the film on which the transfer body 30 is laminated on the substrate 31.

The multi-tone mask 20 is specifically configured to have a light-shielding portion 21 that shields the exposure light when the multi-step mask 20 is used (the transmittance is about 0%); the light-transmitting portion 22 makes the light-transmitting portion The surface of the substrate 1 is exposed to penetrate the exposure light; and the semi-transmissive portion 23 can reduce the transmittance to 10 to 80%, preferably 20 when the transmittance of the light transmittance of the light transmitting portion is set to 100%. ~60%. The semi-transmissive portion 23 is formed by forming a semi-transmissive semi-transparent film 2 on a light-transmissive substrate 1 such as a glass substrate. Further, the light shielding portion 21 is formed by laminating the semi-transmissive film 2 and the light shielding film 3 on the light-transmitting substrate 1. Further, the pattern shapes of the light shielding portion 21, the light transmitting portion 22, and the semi-light transmitting portion 23 shown in Fig. 1 are merely representative examples, and the present invention is of course not limited thereto.

In the semi-transmissive film 2, a material containing a metal and bismuth (Si) or a material selected from the group consisting of ruthenium (Ta), hafnium (Hf), zirconium (Zr), tungsten (W), zinc (Zn), and molybdenum is used. Mo), titanium (Ti), vanadium (V), yttrium (Y), rhenium (Rh), niobium (Nb), lanthanum (La), palladium (Pd), iron (Fe), aluminum (Al), niobium ( Ge) and a material of one or more metals in tin (Sn). A material containing chromium (Cr) is used for the light shielding film 3.

In the light shielding portion 21, the optical density (OD) of the laminated structure of the light shielding film 3 and the semi-transmissive film 2 is preferably set to 2.8 by selecting the film material and the film thickness of the light shielding film 3 and the semi-transmissive film 2, respectively. The above (the transmittance with respect to the exposure light is about 0.16% or less). Further, it is most preferable to set the optical density (OD) of the laminated structure of the light shielding film 3 and the semi-transmissive film 2 to 3.0 or more (the transmittance with respect to the exposure light is 0.1% or less). The transmittance of the semi-transmissive portion 23 is set by selecting the film material and film thickness of the semi-transmissive film 2.

Further, when the exposure light for performing exposure transfer using the multi-tone mask 20 is used as a light source using the multi-color light of the ultrahigh pressure mercury lamp, the optical density and the transmittance of the light shielding portion 21, the semi-light transmitting portion 23, and the like are used. It is necessary to adjust at least one of the i-line (wavelength 365 nm), the h-line (wavelength 405 nm), and the g-line (wavelength 436 nm) which is at least the peak wavelength of the exposure light to be the predetermined optical density and transmittance. Further, it is more desirable to adjust so as to satisfy the predetermined optical density and the transmittance of a predetermined range even at any of the i-line, the h-line, and the g-line.

When the above-described multi-tone mask 20 is used, the exposure light does not substantially penetrate through the light shielding portion 21, and the exposure light is lowered in the semi-light transmitting portion 23. Therefore, when the photoresist film (for example, the positive-type photoresist film) formed on the transfer target 30 is subjected to development after transfer, the film thickness corresponding to the portion of the light-shielding portion 21 becomes thicker, corresponding to half. The film thickness of the portion of the light transmitting portion 23 is relatively thin, and a residual film is not substantially generated corresponding to the portion of the light transmitting portion 22, and as a result, a third-order photoresist pattern 33 can be formed (see FIG. 1). In this resist pattern 33, the effect of thinning the film thickness corresponding to the portion of the semi-transmissive portion 23 is referred to as a gray scale effect. Further, in the case of using a negative-type photoresist, it is necessary to design in consideration of the inversion of the thickness of the photoresist film corresponding to the light-shielding portion and the light-transmitting portion.

Further, in the film-free portion of the resist pattern 33 shown in FIG. 1, for example, the first etching is performed on the films 32A and 32B in the transfer target 30, and the thin portion of the photoresist pattern 33 is ashed or the like. The second etching is performed on, for example, the film 32B of the transfer target 30 by the portion removed by the ashing or the like. In this manner, a single multi-step mask 20 can be used to implement the conventional two-mask process, and the number of masks is reduced.

Further, the multi-step mask 20 shown in FIG. 1 is formed of a light-shielding substrate 1 having a light-shielding portion 21, a light-transmitting portion 22, and a semi-transmissive portion 23 having a predetermined exposure light transmittance. The third-order mask of the transfer pattern is provided with a plurality of semi-transmissive portions and a light-shielding portion and a light-transmitting portion having different exposure light transmittances to form a mask of more than four-order tone.

Next, an embodiment of the manufacturing method of the multi-tone mask of the present invention will be described.

2 is a schematic cross-sectional view showing a process of displaying a multi-tone mask in a process sequence.

In the present embodiment, a three-step mask having a light shielding portion, a light transmitting portion, and a semi-light transmitting portion shown in FIG. 1 described above will be described as an example.

The mask blank 10 used in the present embodiment is sequentially laminated on the light-transmitting substrate 1 : the semi-transmissive film 2 is made of a material containing metal and bismuth (Si) or contains lanthanum (Ta).铪 (Hf), zirconium (Zr), tungsten (W), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium (V), yttrium (Y), yttrium (Rh), niobium (Nb), a material composed of one or more metals of lanthanum (La), palladium (Pd), iron (Fe), aluminum (Al), lanthanum (Ge), and tin (Sn); and a light-shielding film 3 containing chromium ( A material composed of Cr) is further formed by applying a photoresist to the light-shielding film 3 to form a photoresist film 4 (see FIG. 2(a)). In the present embodiment, the transmittance of the light shielding portion in the manufactured third-order mask is determined by the laminate of the light shielding film 3 and the semi-transmissive film 2. By selecting the film material and film thickness of the light-shielding film 3 and the semi-transmissive film 2, the overall optical density is preferably 2.8 or more, and it is most preferable to set it to 3.0 or more. Further, the transmittance of the semi-transmissive portion in the third-order mask is set by selecting the film material and film thickness of the semi-transmissive film 2. Depending on the design value required, the transmittance of the semi-transmissive portion is usually set to, for example, 10 to 80%, preferably 20 to 20, when the light transmittance of the light transmitting portion is set to 100%. 60% is appropriate.

The translucent substrate 1 for a mask blank is not particularly limited as long as it has transparency to the exposure wavelength to be used, and a synthetic quartz substrate or various other glass substrates (for example, soda lime glass, aluminum silicate glass, etc.) can be used. In particular, it is preferred to use a synthetic quartz substrate. Further, the light-transmitting substrate 1 used for the multi-step mask blank is generally 500 mm or more on one side. At present, the short side of the substrate × the long side has various sizes ranging from 500 mm × 800 mm to 2140 mm × 2460 mm, and the thickness is also in the range of 10 mm to 15 mm.

When the semi-transmissive film 2 is made of a material containing a metal or cerium (Si), examples of applicable metals include Mo, Hf, Zr, Ge, Sn, W, Zn, Ni, Y, Ti, and V. , Rh, Nb, La, Pd, Fe, Ge, Al, and the like. In particular, when Mo, Hf, Zr, W, Ti, V, Nb, and Al are applied, the etching rate at the time of etching the semi-transmissive film by the non-excited state substance containing the fluorine-based compound of the present invention can be improved, and The wavelength dependence of the exposure light transmittance of the semi-transparent film (especially the wavelength region of the i-line to the g-line) can be reduced, which is preferred. The ratio of the metal (M) to the cerium (Si) in the semi-transmissive film 2 of the materials is preferably in the range of M:Si = 1:2 to 1:19. The semi-transmissive film 2 is a material containing a transition metal and ruthenium, and is more desirable because it forms a transition metal ruthenium compound. In particular, molybdenum (Mo) is suitable among the transition metals. The ratio of molybdenum (Mo) to bismuth (Si) in the semi-transmissive film 2 containing a material of molybdenum (Mo) and bismuth (Si) is preferably in the range of Mo:Si = 1:2 to 1:19.

The semi-transmissive film 2 using a material containing a metal and bismuth (Si) may further contain nitrogen. When nitrogen is contained, the crystal grain size of the film can be made fine, the film stress is lowered, and the adhesion to the light-transmitting substrate 1 can be improved, which is an effect. When a material containing a metal or cerium (Si) contains an element such as nitrogen or carbon, the content of the element is preferably 40 atom% or less, more preferably 30 atom% or less. Thereby, the etching rate at the time of etching the semi-transmissive film 2 by the non-excited state substance containing the fluorine-based compound of the present invention can be improved.

When the semi-transmissive film 2 is suitably selected from the group consisting of tantalum (Ta), hafnium (Hf), zirconium (Zr), tungsten (W), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium (V) , one or more metals of yttrium (Y), yttrium (Rh), niobium (Nb), lanthanum (La), palladium (Pd), iron (Fe), aluminum (Al), yttrium (Ge), and tin (Sn) In the case of the material, in addition to the metal monomer or alloy, a metal monomer, an alloy nitride, an oxide, an oxynitride or the like may be mentioned. Further, when any of the metal elements of Ta, Mo, Hf, Zr, W, Ti, V, Nb, and Al among the metals shown above or an alloy selected from the metals is used as the semi-transmissive film 2 When the metal is used, the etching rate at the time of etching the semi-transmissive film 2 by the non-excited state substance containing the fluorine-based compound of the present invention can be further improved, which is preferred by the present invention.

The material of the semi-transmissive film 2 is particularly preferably a material containing tantalum (Ta). In addition to tantalum monomers, tantalum nitride (TaN), tantalum oxide (TaO), tantalum nitrogen oxide (TaNO), and the like, and materials containing germanium and one or more elements selected from the group consisting of germanium and boron may be mentioned. Also good. Specific examples of the material containing cerium and lanthanum include TaSi, TaSiN, TaSiO, and TaSiON. Examples of the material containing cerium and boron include TaB, TaBN, TaBO, TaBON, and the like. Examples of the material of boron include TaSiB, TaSiBN, TaSiBO, TaSiBON, and the like.

When boron is contained in the material containing ruthenium, the wavelength dependence of the light transmittance of the semi-transmissive film (especially the wavelength region of the i-line to the g-line) becomes small. In this case, the boron content is preferably 40 atom% or less.

Further, when the material containing ruthenium further contains an element such as nitrogen or carbon, the content of the element is preferably 40 atom% or less, and more preferably 30 atom% or less. Thereby, the etching rate at the time of etching the semi-transmissive film 2 by the non-excited state substance containing the fluorine-based compound of the present invention can be improved.

The light-shielding film 3 is made of a material containing chromium (Cr), and a material containing an element such as nitrogen, oxygen, or carbon in the chromium may be used as the material of the light-shielding film, and examples thereof include CrN, CrO, and CrC. , CrON, CrCN, CrOC, CrOCN, etc. In particular, it is preferred that the material containing chromium contains nitrogen. By containing nitrogen, the etching rate of the etchant used for the wet etching of the light-shielding film becomes faster. Therefore, when the photoresist film having the light-shielding portion pattern formed on the light-shielding film is used as a mask, when the light-shielding film is wet-etched, the etching selectivity of the light-shielding film and the semi-transmissive film is further improved, and In order to suppress damage of the semi-transparent film under the light shielding film. When the light-shielding film containing chromium contains nitrogen, the nitrogen content is preferably in the range of 15 to 60 atom%. If the nitrogen content is less than 15 atom%, the above effects cannot be sufficiently obtained. On the other hand, when the content exceeds 60 atom% and the ultrahigh pressure mercury lamp is used as the light source for the exposure light, in order to obtain a predetermined optical density from the i-line to the g-line wavelength band, it is necessary to increase the film thickness, which may occur. The problem that the CD accuracy is lowered when the light shielding portion pattern is formed. Furthermore, the CD accuracy when the light-shielding film is used as an etch mask to form a semi-transmissive portion pattern is also lowered.

Next, a process of using the multi-tone (3rd-order) mask of the above-described mask blank 10 will be described.

First, the first drawing is performed. In the case of drawing, in the present embodiment, laser light (for example, a predetermined wavelength light in the range of 400 to 450 nm) is used. The photoresist uses a positive photoresist. In the photoresist film 4 on the light-shielding film 3, a predetermined element pattern (a light-transmitting portion pattern, that is, a pattern in which a photoresist pattern is formed corresponding to a region of the light-shielding portion and the semi-light-transmitting portion) is drawn, and development is performed after drawing. Thereby, the photoresist pattern 4a having the light transmitting portion pattern is formed (see FIG. 2(b)).

Next, the light-shielding film 3 is etched by using the photoresist pattern 4a as a mask, whereby the semi-transmissive film 2 corresponding to the light-transmitting portion is exposed, and the light-transmitting portion pattern is formed on the light-shielding film 3 (refer to FIG. 2(c) ). In the case where the light-shielding film 3 composed of a material containing chromium is used, one of dry etching or wet etching may be used as the etching means, and wet etching is used in the present embodiment. Especially in the manufacture of masks for large substrate sizes, wet etching is suitable. As the etching liquid used for the wet etching, for example, a mixed solution of cerium ammonium nitrate and perchloric acid is used. The remaining photoresist pattern 4a is removed (see FIG. 2(d)).

Next, the light transmissive portion pattern formed by the light shielding film 3 is used as a mask, and the semitransparent film 2 on the exposed light transmitting portion is etched to form a light transmitting portion (see FIG. 2(e)).

In the etching process of the related semi-transmissive film 2, since the light-transmitting portion pattern formed on the light-shielding film 3 is used as an etching mask, the light-shielding film 3 and the semi-transmissive film 2 are relatively transparent to each other. The etching selectivity of the etchant used for the etching of the film 2 is necessary, and in order to reduce the damage of the surface of the substrate (glass substrate) after the semi-transmissive film 2 is removed, the semi-transmissive film 2 and the light-transmitting substrate 1 are The etching selectivity of the etchant used for etching with respect to the semi-transmissive film 2 also becomes necessary.

The etchant used for etching the semi-transmissive film 2 is made of an element of fluorine (Cl), bromine (Br), iodine (I), and xenon (Xe) and fluorine (F). The compound, that is, the non-excited state substance containing the fluorine-based compound of the present invention is applied.

The fluorine-based compound material of the present invention in a non-excited state, the light-shielding film 3 composed of a material containing chromium and a material containing metal and ruthenium or containing a material selected from the group consisting of tantalum (Ta), hafnium (Hf), and zirconium ( Zr), tungsten (W), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium (V), yttrium (Y), rhodium (Rh), niobium (Nb), lanthanum (La), palladium ( High etching selectivity can be obtained between the semi-transmissive films 2 composed of a material of one or more metals of Pd), iron (Fe), aluminum (Al), germanium (Ge), and tin (Sn).

Further, the glass substrate used as the light-transmitting substrate 1 has a property that the fluorine-based gas plasma of the present invention is easily etched with respect to the excited state used for dry etching, and the fluorine-based compound material of the present invention with respect to the non-excited state. It is not easy to be etched. Therefore, a high etching selectivity can be obtained between the glass substrate and the semi-transmissive film 2 with respect to the fluorine-based compound substance of the present invention in a non-excited state.

As the fluorine-based compound of the present invention, for example, a compound such as ClF ₃ , ClF, BrF ₅ , BrF, IF ₃ , IF ₅ or XeF ₂ can be preferably used, and among them, ClF _{3 is} particularly preferably used.

The fluorine-based compound substance in the non-excited state may be brought into contact in a fluid state, and it is preferable to contact it in a gas state.

In the etching process of the semi-transmissive film 2, the method of contacting the semi-transmissive film 2 with the non-excited state substance containing the fluorine-based compound of the present invention is preferably, for example, a processing substrate is disposed in the chamber (also That is, for the sake of convenience of explanation, the substrate in the state shown in FIG. 2(d) is referred to as a "processing substrate", and a substance containing the fluorine-based compound of the present invention is introduced into the chamber in a gaseous state to introduce a cavity. The method of replacing the chamber with this gas.

When the substance containing the fluorine-based compound of the present invention is used in a gaseous state, it is preferred to use the fluorine-based compound of the present invention and a nitrogen gas, or argon (Ar), helium (He), neon (Ne), or cerium ( A mixed gas of a rare gas such as Kr), xenon (Xe), rhodium (Rn) or the like (hereinafter simply referred to as argon (Ar) or the like).

The processing conditions (for example, gas flow rate, gas pressure, temperature, and treatment time) in the case where the semi-transmissive film 2 of the substrate is brought into contact with the non-excited gas state substance containing the fluorine-based compound of the present invention are not particularly limited. However, it is desirable to appropriately select the material and film thickness of the semi-transmissive film and the light-shielding film from the viewpoint that the action of the present invention can be preferably obtained.

When the gas flow rate is, for example, a mixed gas of a fluorine-based compound of the present invention and argon or the like, the fluorine-based compound of the present invention is preferably mixed at a flow ratio of 1% or more. When the flow rate of the fluorine-based compound of the present invention is smaller than the flow rate ratio, the progress of etching of the semi-transmissive film 2 is slowed, and as a result, the treatment time becomes long, and the amount of side etching becomes large.

Further, it is preferable that the gas pressure is appropriately selected in the range of, for example, 100 to 760 Torr. When the gas pressure is lower than the above range, the amount of the fluorine-based compound of the present invention in the chamber itself is too small, and the etching of the semi-transmissive film 2 is slowed down, so that the treatment time becomes long and the amount of side etching becomes large. . On the other hand, if the gas pressure is higher than the above range (atmospheric pressure or higher), the gas may flow out of the chamber, and the fluorine-based compound of the present invention also contains a highly toxic gas, which is not preferred.

Further, as for the gas temperature, for example, it is preferably selected in the range of 50 to 250 °C. When the temperature is lower than the above range, the etching progress of the semi-transmissive film 2 becomes slow, and as a result, the treatment time becomes long, and the amount of side etching becomes large. On the other hand, when the temperature is higher than the above range, the etching proceeds rapidly, and the treatment time can be shortened. However, it is difficult to obtain the selectivity of the semi-transmissive film and the substrate, and the substrate damage may be slightly increased.

Further, regarding the treatment time, it is basically sufficient time to complete the etching of the semi-transmissive film 2. Although it differs depending on the gas flow rate, the gas pressure, the temperature, or the material and film thickness of the semi-transmissive film, the effect of the present invention can be preferably obtained in the range of approximately 20 seconds to 300 seconds.

Fig. 4 is a schematic view showing a configuration of a suitable etching apparatus used in the etching process of the above semi-transmissive film.

This etching apparatus constitutes a non-excited gas supply machine by the gas filling containers 43, 44, the flow rate controllers 45, 46, the discharge nozzles 47, and the connecting pipes. The processing substrate (mask blank) 41 is disposed on the platform 42 in the chamber 40 of the processing apparatus. Further, for example, the gases in the two types of gas filling containers 43, 44 are sent to the flow rate controllers 45, 46 to adjust the flow rate, are mixed, are discharged from the discharge nozzles 47, and are introduced into the chamber 40. Further, the gas system in the chamber 40 is appropriately exhausted through the exhaust pipe 48 by an exhaust pump (gas discharger) 49.

When the gas containing the fluorine-based compound of the present invention is used in a gaseous state, the gas of the above-mentioned two types is a rare gas such as a fluorine-based compound or a nitrogen gas or argon (Ar).

Further, the photoresist pattern 4a is removed at the stage of the etching process of the light-shielding film 3 before the end of the process, but the etching process of the semi-transmissive film 2 may be performed in the state of the residual photoresist pattern 4a. In this case, the surface of the light-shielding film 3 can be prevented from being exposed to the fluorine-based compound substance in a non-excited state and protected. On the other hand, when the photoresist pattern 4a is removed, since the fluorine-based compound substance in the non-excited state is more uniformly supplied into the main surface, the pattern accuracy can be further improved.

Next, the entire substrate of the etching process of the semi-transmissive film 2 is completed, and a photoresist film is formed in the same manner as described above (in the case where the photoresist pattern 4a is not removed, it is removed before the formation of the photoresist film). 2 times of depiction. In the second drawing, a predetermined pattern is drawn so that a photoresist pattern is formed on the light shielding portion region. After the drawing, development is performed to form the photoresist pattern 4b on the region corresponding to the light shielding portion (see FIG. 2(f)).

Next, the light-shielding film 3 on the exposed semi-transmissive portion region is etched by using the photoresist pattern 4b as a mask, and a pattern corresponding to the light-shielding portion is formed on the light-shielding film 3. The etching means in this case is preferably wet etching as described above. Thereby, the semi-transmissive film 2 on the semi-transmissive portion region is exposed to form a semi-transmissive portion (see FIG. 2(g)). Then, the remaining photoresist pattern 4b is removed.

The third-order mask 20 is completed in this manner, and has a light-shielding portion 21 formed of a laminated film of the semi-transmissive film 2 and the light-shielding film 3, and light-transmitting the light-transmitting substrate 1 on the light-transmitting substrate 1. The portion 22 and the semi-transmissive portion 23 formed of the semi-transmissive film 2 (see FIG. 2(h)).

According to the manufacturing method of the multi-tone mask described above, the material containing metal and bismuth or containing lanthanum (Ta), hafnium (Hf), zirconium (Zr), tungsten (W), zinc (Zn), Molybdenum (Mo), titanium (Ti), vanadium (V), yttrium (Y), yttrium (Rh), niobium (Nb), lanthanum (La), palladium (Pd), iron (Fe), aluminum (Al), A semi-transmissive film comprising a material of one or more metals of germanium (Ge) and tin (Sn) has a high etching rate for a non-excited state (preferably a non-excited gas state) of the fluorine-containing compound of the present invention. On the other hand, in the case where the glass of the light-transmitting substrate material has a large etching rate with respect to the non-excited state, a high etching selectivity can be obtained between the light-transmitting substrate and the semi-transmissive film. Thereby, in the case where the semi-transmissive film which is a portion of the light-transmitting portion of the multi-step mask is etched and removed by the non-excited state material, a multi-step mask is formed, which is comparable to the case of wet etching. Improve the in-plane uniformity of the CD of the semi-transparent film pattern.

In particular, in the case of a semi-transmissive film composed of a material containing ruthenium, it is possible to suppress pit-shaped concave defects occurring on the surface of the substrate after etching and removing the semi-transmissive film. Thereby, the in-plane uniformity of the light transmittance of the light-transmitting portion can be improved, and when the pattern is exposed and transferred to the photoresist film of the transferred body by using the multi-step mask, the photoresist film is displayed. The amount of residual film like the latter can also be controlled with high precision.

Further, since the etching by the non-excited state material containing the fluorine-based compound of the present invention is applied, the chamber to be etched can be sufficiently utilized as long as it can be adjusted to a certain low pressure. Therefore, it is no longer necessary to use a large chamber for high vacuum like a dry etching apparatus or a large-scale plasma generating apparatus for generating plasma on the main surface of the substrate, and it is possible to achieve a large production cost reduction.

Furthermore, damage to the substrate after the semi-transmissive film is removed by etching can be reduced. Therefore, even in the case of regenerating the substrate, the process burden of re-polishing is reduced, so that the regeneration cost of the substrate can be reduced. Since a high-quality substrate can be regenerated at low cost, it is particularly suitable for reproducing a multi-step mask substrate using an expensive substrate (high added value).

Further, the above-described multi-step mask manufacturing method can be easily realized by using the etching apparatus described above.

Next, other aspects of the method of manufacturing the multi-order mask of the present invention will be described.

Figure 3 is a schematic cross-sectional view showing the process of the multi-step mask of the different processes shown in Figure 2 in a process sequence. The 3rd order mask of Fig. 2(h) is basically the same as the 3rd order mask of Fig. 3(f), and there are some differences in the manufacturing procedure.

The manufacturing method of the multi-tone mask of FIG. 2 is different in that the photoresist pattern 4b having the light-shielding portion pattern is formed by the first drawing and development of the photoresist film 4 (refer to FIG. 3 (refer to FIG. 3 b)), the light-shielding film 3 is etched by using the photoresist pattern 4b as a mask to form a light-shielding portion pattern (see FIG. 3(c)), and after the light-shielding film pattern is formed in the light-shielding film 3, the light-shielding film 3 and the semi-transparent film A photoresist film is formed on the photo film 2, and a photoresist pattern 4a having a pattern of a light transmitting portion is formed by second drawing and development (see FIG. 3(d)), and then the photoresist pattern 4a is used as a mask. The semi-transmissive film 2 is etched to form a light transmitting portion pattern (refer to FIG. 3(e)).

In the case of the multi-step mask process shown in FIG. 3, there is an advantage that the light-shielding film 3 can be formed by etching only once. However, since the photoresist pattern 4a of the organic material is used as a mask, and the semi-transmissive film 2 is etched to form a light-transmitting portion pattern, the light-shielding film 3 of the metal-based material is shielded as compared with the process of FIG. In the case where the cover is etched to form the pattern of the light transmitting portion, the pattern accuracy may be somewhat lowered.

Hereinafter, embodiments of the present invention will be more specifically described by way of examples. A comparison will be made in comparison with the comparative examples of the examples.

(Example 1)

On a light-transmissive substrate (1220 mm × 1400 mm × 13 mm) composed of synthetic quartz glass, a sputtering device was used, and a mixed sintered target of molybdenum (Mo) and bismuth (Si) was used for the sputtering target (Mo: Si = 20: 80, atomic % ratio), a MoSi ₄ semi-transmissive film was formed by reactive sputtering (DC sputtering) in an argon (Ar) gas atmosphere. Further, the film thickness was set to 5 nm in order to make the transmittance at the i-line (365 nm) wavelength 40%.

Next, on the semi-transmissive film, a sputtering target is formed by using a chromium (Cr) target in a mixed gas atmosphere of argon (Ar) and nitrogen (N ₂ ) by reactive sputtering (DC sputtering). A CrN layer having a film thickness of 15 nm. Next, a CrCN layer having a film thickness of 65 nm was formed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon (Ar) and methane (CH ₄ ) and nitrogen (N ₂ ). Next, a CrON layer having a film thickness of 25 nm was formed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon (Ar) and nitrogen monoxide (NO). In this manner, a chromium-based light-shielding film having a total film thickness of 105 nm was formed. This light-shielding film is a film having a gradient structure in which the composition of each layer is adjusted so that the laminated structure of the semi-transmissive film becomes an optical density of 3.0 at an i-line (365 nm) wavelength.

According to the above aspect, a mask blank in which a molybdenum telluride-based semi-transmissive film and a chromium-based light-shielding film are sequentially laminated on a light-transmitting substrate is produced.

Next, following the process of Figure 2 above, the mask blank is used to make a 3rd-order mask.

First, the first drawing is performed using laser light (wavelength 412 nm). A positive photoresist is used in terms of photoresist. A predetermined element pattern is drawn on the photoresist film applied to the light-shielding film, and after development, a photoresist pattern having a light-transmitting portion pattern is formed (see FIG. 2(b)).

Next, the light-shielding film is wet-etched by using the photoresist pattern as a mask, so that the semi-transmissive film corresponding to the light-transmitting portion region is exposed, and the light-transmitting portion pattern is formed on the light-shielding film (see FIG. 2(c)). An etching solution containing cerium ammonium nitrate and perchloric acid is used in the etching solution at normal temperature. After the etching, the remaining photoresist pattern 4a is removed (see FIG. 2(d)).

Next, the light transmissive portion pattern formed on the light shielding film is used as a mask, and the semitransparent film on the exposed light transmitting portion is etched to form a light transmitting portion exposed on the surface of the substrate (see FIG. 2(e)).

The etching of the semi-transmissive film is carried out using the etching apparatus shown in Fig. 4 described above. In other words, a substrate in a state in which the light-transmitting portion pattern is formed in the light-shielding film is provided in the chamber, and a mixed gas of ClF ₃ and Ar is introduced into the chamber (flow ratio ClF ₃ : Ar = 0.2: 1.8 (SLM)). The chamber is replaced with the gas, whereby the semi-transmissive film exposed on the light-transmitting portion is brought into contact with the mixed gas in a non-excited state. At this time, the gas pressure was adjusted to 488 to 502 Torr, the temperature was adjusted to 195 to 202 ° C, and the treatment time (etching time) was set to 36 seconds.

Next, the positive resist film was formed in the same manner as described above after the etching process of the semi-transmissive film was completed, and the second drawing was performed. In the second drawing, a predetermined pattern is drawn so as to form a photoresist pattern on the light shielding portion region, and after development, development is performed to form a photoresist pattern on a region corresponding to the light shielding portion (see FIG. 2(f) ).

Next, the light-shielding film on the exposed semi-transmissive portion is wet-etched by using the photoresist pattern as a mask, and a pattern corresponding to the light-shielding portion is formed on the light-shielding film. In the etching liquid in this case, the same etching liquid as described above was used. Thereby, the semi-transmissive film on the semi-transmissive portion region is exposed to form a semi-transmissive portion (see FIG. 2(g)). Then, the remaining photoresist pattern is removed in the same manner as before.

In this manner, a third-order mask is formed, which is a light-shielding portion formed of a laminated film having a semi-transmissive film and a light-shielding film on a glass substrate, a light-transmitting portion in which the glass substrate is exposed, and a semi-transparent film. Semi-transmissive portion (see Fig. 2(h)).

With respect to the produced third-order mask, the surface of the glass substrate in which the light-transmissive portion of the semi-transmissive film was removed by etching was observed by an electron microscope, and the residue of the semi-transparent film or the deterioration of white turbidity was not confirmed. The occurrence of the layer. As a result of measuring the surface reflectance (200 to 700 nm) of the glass substrate in the light-transmitting portion region, there was no change in the substrate before the film formation, and no pit-shaped concave defects were observed. The decrease in the transmittance of the exposure light due to the thickness of the surface of the substrate is also small, and the uniformity of the transmittance distribution of the exposure light in the plane is also high. It was confirmed that the in-plane uniformity of the CD of the semi-transmissive portion (semi-transmissive film pattern) was also good.

In addition, by using the prepared third-order mask, the photoresist film of the transferred body is subjected to pattern transfer exposure using an ultrahigh pressure mercury lamp as an exposure light source, and as a result, it is confirmed that the residual film amount after the photoresist film is developed can also be Controlled with high precision.

In addition, the surface roughness of the main surface of the substrate of the light-transmitting portion of the third-order mask is reproduced, and the substrate of the third-order mask is reproduced by re-precision grinding on the surface of the substrate (usually in the polishing process) The final stage) can easily restore the level of surface roughness.

(Example 2)

On a light-transmissive substrate (1220 mm × 1400 mm × 13 mm) composed of synthetic quartz glass, a sputtering device was used, and a tantalum (Ta) target was used for the sputtering target, and reactive sputtering was performed under an argon (Ar) gas atmosphere. Plating (DC sputtering) to form a Ta semi-transmissive film. Further, the film thickness was set to 4 nm in order to make the transmittance at the i-line (365 nm) wavelength 40%.

Next, on the semi-transmissive film, a chromium (Cr) target is used for the sputtering target, and reactive sputtering (DC sputtering) is used in a mixed gas atmosphere of argon (Ar) and nitrogen (N ₂ ). A CrN layer having a film thickness of 15 nm was formed. Next, a CrCN layer having a film thickness of 65 nm was formed by reactive sputtering (DC sputtering) in an atmosphere of a mixed gas of argon (Ar) and methane (CH ₄ ) and nitrogen (N ₂ ). Next, a CrON layer having a film thickness of 25 nm was formed by reactive sputtering (DC sputtering) in a mixed gas atmosphere of argon (Ar) and nitrogen monoxide (NO). In this manner, a chromium-based light-shielding film having a total film thickness of 105 nm was formed. Each of the light-shielding films has a film having a gradient structure, and is adjusted so that the laminated structure of the semi-transmissive film becomes an optical density of 3.0 at an i-line (365 nm) wavelength.

According to the above aspect, a mask blank in which a bismuth-based semi-transmissive film and a chromium-based light-shielding film are sequentially laminated on the light-transmitting substrate is produced.

Next, according to the process of FIG. 2 described above, the mask blank is used to make a 3rd-order mask.

First, the first drawing is performed using laser light (wavelength 412 nm). A positive photoresist is used in terms of photoresist. A predetermined element pattern is drawn on the photoresist film applied to the light-shielding film, and developed after drawing, thereby forming a photoresist pattern having a light-transmitting portion pattern (see FIG. 2(b)).

Next, using the photoresist pattern as a mask, the light-shielding film is wet-etched to expose the semi-transmissive film corresponding to the light-transmitting portion, and the light-transmitting portion pattern is formed on the light-shielding film (see FIG. 2(c)). The etching solution is an etchant containing cerium ammonium nitrate and perchloric acid at normal temperature. After the etching, the remaining photoresist pattern 4a is removed (see FIG. 2(d)).

Next, the light transmissive portion pattern formed by the light shielding film is a mask, and the semitransparent film on the exposed light transmitting portion is etched to form a light transmitting portion exposed on the surface of the substrate (see FIG. 2(e)). .

The etching of the semi-transmissive film is carried out using the etching apparatus shown in Fig. 4 described above. In other words, a substrate in a state in which the light-transmitting portion pattern is formed in the light-shielding film is provided in the chamber, and a mixed gas of ClF ₃ and Ar is introduced into the chamber (flow ratio ClF ₃ : Ar = 0.2: 1.8 (SLM)). The chamber is replaced with the gas, whereby the semi-transmissive film exposed on the light-transmitting portion is brought into contact with the mixed gas in a non-excited state. At this time, the gas pressure was adjusted to 488 to 502 Torr, the temperature was adjusted to 110 to 120 ° C, and the treatment time (etching time) was set to 32 seconds.

Next, the positive resist film was formed in the same manner as described above after the etching process of the semi-transmissive film was completed, and the second drawing was performed. In the second drawing, a predetermined pattern is drawn so as to form a photoresist pattern on the light shielding portion region, and after development, development is performed to form a photoresist pattern on a region corresponding to the light shielding portion (see FIG. 2(f) ).

Next, the positive resist film was formed in the same manner as described above after the etching process of the semi-transmissive film was completed, and the second drawing was performed. In the second drawing, a predetermined pattern is drawn so as to form a photoresist pattern on the light shielding portion region, and after development, development is performed to form a photoresist pattern on a region corresponding to the light shielding portion (see FIG. 2(f) ).

Next, the light-shielding film on the exposed semi-transmissive portion is wet-etched by using the photoresist pattern as a mask, and a pattern corresponding to the light-shielding portion is formed on the light-shielding film. In the etching liquid in this case, the same etching liquid as described above was used. Thereby, the semi-transmissive film on the semi-transmissive portion region is exposed to form a semi-transmissive portion (see FIG. 2(g)). Then, the remaining photoresist pattern is removed in the same manner as before.

In this manner, a third-order mask is formed, which is a light-shielding portion formed by a laminated film of a semi-transmissive film and a light-shielding film on a glass substrate, a light-transmitting portion in which the glass substrate is exposed, and a semi-transparent film. Semi-transmissive portion (see Fig. 2(h)).

With respect to the produced third-order mask, the surface of the glass substrate in which the light-transmissive portion of the semi-transmissive film was removed by etching was observed by an electron microscope, and the residue of the semi-transparent film or the deterioration of white turbidity was not confirmed. The occurrence of the layer. Further, as a result of measuring the surface reflectance (200 to 700 nm) of the glass substrate in the light transmitting portion region, there was no change in the substrate before the film formation, and no pit-shaped concave defects were observed. The decrease in the transmittance of the exposure light due to the thickness of the surface of the substrate is also small, and the uniformity of the transmittance distribution of the exposure light in the plane is also high. It was confirmed that the in-plane uniformity of the CD of the semi-transmissive portion (semi-transmissive film pattern) was also good.

In addition, by using the prepared third-order mask, the photoresist film of the transferred body is subjected to pattern transfer exposure using an ultrahigh pressure mercury lamp as an exposure light source, and as a result, it is confirmed that the residual film amount after the photoresist film is developed can also be Controlled with high precision.

In addition, the surface roughness of the main surface of the substrate of the light-transmitting portion of the third-order mask is made by re-precision polishing the surface of the substrate when the substrate of the third-order mask is reproduced (normally, the polishing process) The final stage of the process can easily restore the level of surface roughness.

(Comparative Example 1)

A 3rd-order mask was produced using the same mask blank as in Example 2. Wherein, the light transmissive portion pattern formed by the light shielding film is a mask, and in the process of etching the semi-transparent film on the exposed light transmitting portion region, a sodium hydroxide solution (concentration: 40 wt%, temperature 70) is used. °C) is used as an etching solution. The treatment time (etching time) was 10 minutes.

The other processes were carried out in the same manner as in Example 1, and a third-order mask was produced.

As a result of observing the surface of the glass substrate in the light-transmitting portion in the third-order mask produced by an electron microscope, the residue of the semi-transmissive film was not particularly observed. Further, as a result of measuring the surface reflectance (200 to 700 nm) of the substrate, the reflectance was reduced as a whole as compared with the substrate before the film formation. As a result of observing the surface roughness of the substrate in the light transmitting portion region by an atomic force microscope (AFM), it was confirmed that a large number of pit-like recesses were formed on the surface of the substrate of the light transmitting portion. It was confirmed that the in-plane uniformity of the CD of the semi-transmissive portion (semi-transmissive film pattern) was lower than that of Example 2.

In addition, the result of the exposure transfer of the pattern of the photoresist film of the transfer target with the ultrahigh pressure mercury lamp as the exposure light source, especially in the portion where the concave portion is formed, is formed using the produced 3rd-order mask. The amount of light transmitted through the light is greatly reduced, and it is difficult to say that the amount of residual film after the development of the photoresist film is also controlled.

In addition, the surface roughness of the main surface of the substrate of the light-transmitting portion of the 3rd-order mask is restored to a good surface in order to re-polish the surface of the substrate to remove the pit-shaped recess in the case of reproducing the substrate of the 3rd-order mask. The thickness must be re-grinded at the initial stage of the usual substrate polishing process before film formation, and the process burden of re-grinding becomes large.

Further, the third-order masks produced in the first embodiment and the second embodiment are produced by the manufacturing method of the other embodiment shown in FIG. 3, and the in-plane uniformity of the semi-transmissive portion is It is not as high as the third-order mask produced in the first embodiment and the second embodiment, but that the in-plane uniformity of the semi-transmissive portion is high as compared with the third-order mask produced in the comparative example 1. . Further, it was confirmed that no pit-shaped concave defects were observed on the surface of the substrate of the light transmitting portion, and the decrease in the transmittance of the exposure light due to the surface roughness of the substrate was small, and the uniformity of the transmittance of the exposure light in the in-plane was also high. .

1. . . Light transmissive substrate

2. . . Semi-transparent film

3. . . Sunscreen

4. . . Photoresist film

10. . . Mask blank

20. . . Multi-tone mask

twenty one. . . Shading

twenty two. . . Translucent part

twenty three. . . Semi-transparent part

30. . . Transferred body

31. . . Substrate

32A, 32B. . . membrane

33. . . Resistive pattern

40. . . Chamber

41. . . Processing substrate

42. . . platform

43,44. . . Gas filling container

45,46. . . Flow controller

47. . . Spray nozzle

48. . . exhaust pipe

49. . . Exhaust pump

Fig. 1 is a schematic cross-sectional view for explaining a pattern transfer method using a multi-tone mask.

2(a) to (h) are schematic cross-sectional views showing a process of a multi-step mask.

3(a) to (f) are schematic cross-sectional views showing other forms of the process of the multi-step mask.

Fig. 4 is a schematic configuration diagram of an etching apparatus used in an etching process of a semi-transmissive film.

1. . . Light transmissive substrate

2. . . Semi-transparent film

3. . . Sunscreen

4. . . Photoresist film

4a, 4b. . . Resistive pattern

10. . . Mask blank

20. . . Multi-tone mask

twenty one. . . Shading

twenty two. . . Translucent part

twenty three. . . Semi-transparent part

Claims (12)

A multi-step mask manufacturing method for manufacturing a multi-step transfer pattern comprising a light-shielding portion, a light-transmitting portion, and a semi-transmissive portion penetrating a portion of the exposure light on a glass substrate The mask is characterized in that it has a process of sequentially laminating a material containing metal and tantalum on a glass substrate or containing a material selected from the group consisting of tantalum (Ta), hafnium (Hf), zirconium (Zr), and tungsten (W). ), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium (V), yttrium (Y), yttrium (Rh), niobium (Nb), lanthanum (La), palladium (Pd), iron (Fe) a semi-transmissive film composed of a material of one or more metals of aluminum (Al), germanium (Ge), and tin (Sn), and a mask blank of a light-shielding film composed of a material containing chromium (Cr) a process of forming a pattern of the light-transmitting portion in the light-shielding film; the pattern of the light-transmitting portion formed by the light-shielding film is a mask, and the semi-transmissive film is composed of chlorine (Cl), bromine (Br), a process of etching a non-excited state of a compound of any one of iodine (I) and yttrium (Xe) and a compound of fluorine (F); and a process of forming a light-shielding portion pattern on the light-shielding film. The method for manufacturing a multi-tone mask according to the first aspect of the invention, wherein the light-shielding portion pattern is formed by the light-shielding film having the light-shielding portion pattern formed on the light-shielding film. The mask is wet etched. The method for manufacturing a multi-tone mask according to claim 1, wherein the process of forming the light-transmitting portion pattern in the light-shielding film is performed by using light having a pattern of the light-transmitting portion formed on the light-shielding film. The resist film is performed by wet etching of the mask. The method for manufacturing a multi-tone mask according to claim 3, wherein the process of forming the light-shielding pattern on the light-shielding film is performed by using a photoresist film having a light-shielding pattern formed on the light-shielding film. The mask is wet etched. A multi-step mask manufacturing method for manufacturing a multi-step transfer pattern comprising a light-shielding portion, a light-transmitting portion, and a semi-transmissive portion penetrating a portion of the exposure light on a glass substrate The mask is characterized in that it has a process of sequentially laminating a material containing metal and tantalum on a glass substrate or containing a material selected from the group consisting of tantalum (Ta), hafnium (Hf), zirconium (Zr), and tungsten (W). ), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium (V), yttrium (Y), yttrium (Rh), niobium (Nb), lanthanum (La), palladium (Pd), iron (Fe) a semi-transmissive film composed of a material of one or more metals of aluminum (Al), germanium (Ge), and tin (Sn), and a mask blank of a light-shielding film composed of a material containing chromium (Cr) a process of forming a light-shielding portion pattern on the light-shielding film; a process of forming a photoresist film having a light-transmitting portion pattern on the light-shielding film and the semi-transmissive film; and a light-transmitting portion pattern formed by the light-resist film For the mask, the semi-transmissive film is composed of a compound containing fluorine (F) from an element of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe). A process in which an unexcited state material is subjected to etching. The method for manufacturing a multi-tone mask according to claim 5, wherein the method for forming the light-shielding pattern in the light-shielding film is This is performed by wet etching using a photoresist film having a light-shielding pattern formed on the light-shielding film as a mask. The method of manufacturing a multi-tone mask according to any one of claims 1 to 6, wherein the non-excited state material is a ClF ₃ gas. The method of manufacturing a multi-tone mask according to any one of claims 1 to 6, wherein the metal in the semi-transmissive film is molybdenum (Mo). The method of manufacturing a multi-tone mask according to any one of claims 1 to 6, wherein the semi-transmissive film is made of a material containing tantalum (Ta). The method of manufacturing a multi-tone mask according to any one of claims 1 to 6, wherein the light-shielding film is made of a material further containing nitrogen. The method of manufacturing a multi-tone mask according to any one of claims 1 to 6, wherein the light-transmitting substrate is made of synthetic quartz glass. An apparatus for manufacturing a multi-tone mask according to any one of claims 1 to 6; characterized by: a chamber having a platform for setting the mask blank The non-excited substance supply device supplies a non-excited state substance to the chamber, and a gas discharge device that discharges gas from the chamber.