KR20110116995A - Method of manufacturing multi-gray scale mask and etching device - Google Patents

Abstract

A manufacturing method of a multi-gradation mask having a transfer pattern composed of a light shielding portion 21, a light transmitting portion 22, and a semi-light transmitting portion 23 that transmits a part of exposure light, on a light transmissive substrate 1, comprising: And a mask blank in which a semi-transmissive film 2 made of a material containing silicon or a material containing at least one metal selected from tantalum and the like, and a light shielding film 3 made of a material containing chromium are laminated in this order ( 10) a step of preparing a light-shielding film, a step of forming a light-transmitting pattern on the light-shielding film, and a semi-transmissive film as a mask of the element of chlorine, bromine, iodine, and xenon with fluorine And a step of etching with a substance in a non-excited state containing the compound, and forming a pattern of the light shielding portion in the light shielding film.

Description

Manufacturing method and etching apparatus of a multi-gradation mask {METHOD OF MANUFACTURING MULTI-GRAY SCALE MASK AND ETCHING DEVICE}

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

Currently, in the field of FPD, and especially in the field of LCD, thin film transistor liquid crystal display devices (hereinafter referred to as TFT-LCDs) are commercialized from the advantages of being thin and easy to consume. Is currently progressing rapidly. The TFT-LCD includes a TFT substrate having a structure in which TFTs are arranged in each pixel arranged in a matrix form, and a color filter in which red, green, and blue pixel patterns are arranged in correspondence with each pixel under the liquid crystal phase. It has a schematic structure. In TFT-LCD, there are many manufacturing processes, and even a TFT board | substrate was manufactured using 5-6 photomasks. Under such circumstances, a method of manufacturing a TFT substrate using a smaller photomask has been proposed.

This method is to reduce the number of masks to be used by using a photomask having a light shielding part, a light transmitting part, and a semi-light transmitting part. Here, the semi-transmissive portion refers to a portion that reduces the amount of transmitted light transmitted through a predetermined amount when the pattern is transferred to the transfer target by using a mask to control the amount of remaining film after development of the photoresist film on the transfer target. The photomask equipped with the light transmissive part and the light transmissive part is generally referred to as a gray tone mask. By using the gray-tone mask provided with the light shielding part and the light transmitting part, the desired transfer pattern which includes the part from which three residual gray values differ in the photoresist on a to-be-transferred body is used by using the gray-tone mask provided with the light-shielding part and the light-transmitting part. Can be formed. Further, by using a gray tone mask including a plurality of semi-transmissive portions having different exposure light transmittances together with the light shielding portion and the light transmitting portion, more transfer patterns of four or more gradations can be formed. Such gray tone masks are referred to as "multi-gradation masks" in the present invention.

By the way, in a multi-gradation mask, the thing of the structure in which the said translucent part is formed in the fine pattern below the resolution limit of the exposure machine using a multi-gradation mask is known. The resolution limit of an exposure machine using a multi-gradation mask is in most cases about 3 μm in a stepper type exposure machine and about 4 μm in a mirror projection type exposure machine. However, in order to design such a semi-transmissive portion of such a fine pattern type, the fine pattern for giving a halftone effect between the light-shielding portion and the light-transmitting portion is a line-and-space type or a dot (dotted dot) type, or It is necessary to select whether or not to use other patterns. In the case of the line-and-space type, it is designed in consideration of very many things such as how much the line width is to be set, how is the ratio between the light transmitting part and the light shielding part, and how much the transmittance of the entire translucent part is designed? Must be done. Moreover, also in manufacture of a mask, very difficult production techniques, such as management of the center value of line | wire width and the control of the fluctuation | variation of the line | wire width in a mask, were calculated | required.

Therefore, it has conventionally been proposed to form the semi-transmissive portion as a light semi-transmissive semi-transmissive film. By using this semi-transmissive film, the exposure amount in a semi-transmissive part can be reduced and exposed. In the case of using the translucent film, the design examines how much the total transmittance is necessary, and in the mask, the mask can be produced by selecting the film type (material) or the film thickness of the translucent film. Therefore, in manufacture of a multi-gradation mask, it is sufficient only to control the film thickness of a translucent film, and it is comparatively easy to manage. For example, when the channel portion of the TFT is formed by the semi-transmissive portion of the multi-gradation mask, the semi-transmissive film can be easily patterned by the photolithography process. Thus, even a complicated channel pattern TFT channel portion can form a high precision pattern. There is also the advantage that it is possible.

When forming the translucent part of a multi-tone mask with a translucent film, the silicide compound of metals, such as molybdenum, is widely known as a material of a translucent film. Moreover, as a material of semi-transmissive membranes other than a metal silicide compound, the material which has tantalum as a main component is proposed conventionally (patent document 1: Unexamined-Japanese-Patent No. 2008-249950, patent document 2: Japanese patent publication). Publication 2002-196473). In particular, the material mainly composed of tantalum is i-line which is easy to adjust the exposure light transmittance by adjusting the film thickness, and the exposure wavelength band of the multi-color exposure using the ultra-high pressure mercury lamp widely used in the FPD exposure machine as a light source. There are advantages such as a small change in transmittance with respect to a wavelength change (a small wavelength dependency and a flat spectral characteristic) in the wavelength region over the -g line.

The multi-gradation mask is, for example, a mask in which a semi-transmissive film made of a material containing metal silicide or tantalum and a light shielding film made of chromium as a main component are laminated in this order on a translucent substrate such as synthetic quartz glass. By using a blank, the said light shielding film and the semi-transmissive film are each patterned as desired, and it is manufactured by forming the transfer pattern which consists of a light shielding part, a light transmitting part, and a semi-transmissive part.

The above-described method of manufacturing a multi-gradation mask comprises the steps of forming a pattern of a light-transmitting portion in the light-shielding film by etching the light-shielding film using a resist film having a pattern of the light-transmitting portion formed on the light-shielding film of the mask blank as a mask. Exposing the surface of the light-transmitting substrate to form a light-transmitting portion by etching the semi-transmissive film using the pattern of the light-transmitting portion as a mask, and etching the light-shielding film by using a resist film having a pattern of the light-shielding portion formed on the light-shielding film as a mask. It has a process of forming the pattern of a light shielding part in a light shielding film.

The said etching process can be performed by what is called wet etching or dry etching. However, with the recent trend of increasing the size of FPD devices, the size of substrates has also been increased with respect to the multi-gradation masks used for manufacturing the FPD devices. In other words, in the case of dry etching, a plasma is generated, but a plasma generating apparatus capable of generating plasma over the entire surface of the main surface of a large mask blank, which is much larger than the LSI application, requires a very expensive dry. Etching apparatus must be introduced. Therefore, considering the production cost, the method by dry etching is not practical.

On the other hand, according to the wet etching, such a problem does not occur particularly. As the etching liquid of the light shielding film which consists of a material which has chromium as a main component, the etching liquid containing a dibasic cerium nitrate ammonium and perchloric acid is used normally. In addition, as an etching liquid of the translucent film which consists of a material which has a metal silicide as a main component, the etching liquid containing ammonium hydrogen fluoride and hydrogen peroxide is used, for example. In addition, as an etching liquid of the translucent film which consists of a material which has a tantalum as a main component, aqueous alkali solution, such as sodium hydroxide and potassium hydroxide heated at 50 degreeC or more, is used.

According to the investigation by the present inventors, since the etching rate with respect to aqueous alkali solution is not so large in the case of the semi-transmissive film which consists of a material which has a tantalum as a main component, when the semi-transmissive film is removed by wet etching using aqueous alkali solution, the exposed glass will be It has been found that a large problem occurs as a multi-gradation mask in which a pit-shaped recess is formed on the substrate surface.

Since the light transmissive portion of the multi-gradation mask is formed by wet etching exposing the glass substrate surface, when a pit-shaped recess is generated on the glass substrate constituting the light transmissive portion, the transmittance is greatly reduced. Since the difference in etching time is caused by the ease of etching of the pattern shape for etching the translucent film, it is difficult to suppress the occurrence of the pit-shaped recess even if the etching time is strictly adjusted. When the pattern is exposed-transferred onto the photoresist film of the transfer object using such a multi-gradation mask, there arises a problem that the precision of the remaining film amount control after developing the photoresist film is low.

On the other hand, in the case of the translucent film which consists of a material which has a metal silicide as a main component, the problem that a pit-shaped recessed part generate | occur | produces on the surface of a glass substrate does not arise. However, miniaturization of the pattern formed in the translucent film is progressing, and the in-plane density difference of a resist pattern and a light shielding film pattern becomes larger. At the time of etching the translucent film, the etchant tends to be replaced easily in the coarse pattern portion, and the etching rate tends to be faster, and the etchant is difficult to replace in the dense pattern portion, and the etching rate tends to be lowered. This difference greatly affects the CD in-plane uniformity of the semi-transmissive film pattern after etching. In the case of wet etching, in particular, in a dense pattern, there is a problem that the replacement of the etching liquid is worse than that of the etching gas of dry etching, and the CD in-plane uniformity of the translucent film tends to be lowered.

On the other hand, as a metal material to be applied to the semi-transmissive film of the multi-tone mask, in addition to tantalum, hafnium (Hf), zirconium (Zr), tungsten (W), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium (V), yttrium (Y), rhodium (Rh), niobium (Nb), lanthanum (La), palladium (Pd), iron (Fe), aluminum (Al), germanium (Ge), tin (Sn), etc. It is reviewed so far. As an etchant which wet-etches the translucent film of these metal materials, although alkaline aqueous solution etc. are examined, it is difficult to acquire sufficient etching selectivity between translucent board | substrates similarly to the case of tantalum. In addition, there is also a problem that it is difficult to say that the CD in-plane uniformity of the translucent film is also good.

In recent years, competition for lowering the price of FPD devices has intensified, while suppressing the manufacturing cost of a multi-gradation mask is also an important problem. From such a background, when a pattern defect that is difficult to correct is found in a multi-tone mask fabricated using a mask blank, the thin-film mask is peeled off and removed from the substrate to regenerate the substrate without discarding the multi-tone mask as a defective product. A method is desired.

In order to completely remove the damage that has occurred on the surface of the substrate and regenerate the substrate, it is necessary to regrind and take much amount to be removed by polishing. Surface polishing of the glass substrate before film-forming is normally performed through the several-step grinding process from rough polishing to precision polishing. In the case of re-polishing, it is necessary to take much polishing removal amount as described above, so it is necessary to return to the initial stage in the plural stages of polishing, and it takes a long time for re-polishing, so the process load of re-polishing is large, The cost is high. That is, when manufacturing a multi-gradation mask by the manufacturing method which includes the process of wet-etching using the aqueous alkali solution with respect to the semi-transmissive film which consists of a material which has a tantalum as a main component, the pattern defect which is difficult to correct | amend in the obtained mask is The mask was found to be costly in the case of peeling off and removing the light shielding film and the semi-transmissive film from the substrate with the above etching solution without reposing the mask as a defective product.

In addition, even when regenerating a substrate from a multi-gradation mask having a semi-transmissive film made of a material mainly composed of metal and silicon, deterioration of flatness of the substrate peeled off with the above etching solution is unavoidable, and polishing is performed to correct the flatness. Since it is necessary to take a large amount of removal, a cost is required when regenerating the substrate.

Accordingly, the present invention has been made in view of such various conventional problems, and its object is to eliminate the need for a large-scale, very expensive dry etching apparatus, and in-plane CD when a pattern is formed on a translucent film. The uniformity is higher than that in the case of wet etching, and the process load of re-polishing in the case of regenerating the substrate is reduced, so that the regeneration cost of the substrate can be reduced. In particular, in the case of the semi-transmissive film mainly containing tantalum, the mask manufacturing step The manufacturing method of the multi-gradation mask which can suppress that a pit-shaped recessed part generate | occur | produces on the board | substrate surface of this, and the etching apparatus used by this manufacturing method of a multi-gradation mask are provided.

MEANS TO SOLVE THE PROBLEM In order to solve the said subject, as a result of earnestly examining, the material containing a metal and silicon, or tantalum (Ta), hafnium (Hf), zirconium (Zr), tungsten (W), zinc (Zn), Molybdenum (Mo), Titanium (Ti), Vanadium (V), Yttrium (Y), Rhodium (Rh), Niobium (Nb), Lanthanum (La), Palladium (Pd), Iron (Fe), Aluminum (Al), When etching a translucent film made of a material containing at least one metal selected from germanium (Ge) and tin (Sn), certain fluorine-based compounds such as chlorine (Cl), bromine (Br), iodine (I), and xenon By using a non-excited state material containing a compound of any one of (Xe) and fluorine (F) (hereinafter sometimes referred to as "fluorine compound of the present invention"), the etching after It was found that the CD in-plane uniformity of the semi-transmissive film pattern can be increased. In particular, in the case of etching a semi-transmissive film made of a material containing tantalum, by using a substance in a non-excited state containing the fluorine-based compound of the present invention, a pit shape is formed on the surface of the substrate after the semi-transmissive film is removed by etching. It was found that the occurrence of concave defects can be suppressed.

MEANS TO SOLVE THE PROBLEM This inventor completed this invention as a result of continuing earnest research based on the above-mentioned clarification fact.

That is, in order to solve the said subject, this invention has the following aspects.

(Aspect 1)

A method of manufacturing a multi-tone mask having a transfer pattern comprising a light shielding portion, a light transmitting portion, and a semi-transmissive portion that transmits a part of exposure light, on a light transmitting substrate, comprising: a material containing metal and silicon, or tantalum (on a light transmitting substrate) Ta, hafnium (Hf), zirconium (Zr), tungsten (W), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium (V), yttrium (Y), rhodium (Rh), niobium ( A translucent film made of a material containing at least one metal selected from Nb), lanthanum (La), palladium (Pd), iron (Fe), aluminum (Al), germanium (Ge) and tin (Sn), and chromium The process of preparing the mask blank which laminated | stacked the light shielding film which consists of a material containing (Cr) in this order, the process of forming the pattern of the light transmission part in the said light shielding film, and the said pattern by using the pattern of the light transmission part formed in the said light shielding film as a mask The light-transmitting film is formed of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe). And a step of etching with a substance in a non-excited state containing a compound with fluorine (F) and a step of forming a pattern of light shielding portions in the light shielding film.

(Aspect 2)

The step of forming the pattern of the light transmitting portion in the light shielding film is performed by wet etching using a resist film having a pattern of the light transmitting portion formed on the light shielding film as a mask.

(Aspect 3)

A method of manufacturing a multi-tone mask having a transfer pattern comprising a light shielding portion, a light transmitting portion, and a semi-transmissive portion that transmits a part of exposure light, on a light transmitting substrate, comprising: a material containing metal and silicon, or tantalum (on a light transmitting substrate) Ta, hafnium (Hf), zirconium (Zr), tungsten (W), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium (V), yttrium (Y), rhodium (Rh), niobium ( A translucent film made of a material containing at least one metal selected from Nb), lanthanum (La), palladium (Pd), iron (Fe), aluminum (Al), germanium (Ge) and tin (Sn), and chromium Preparing a mask blank in which a light shielding film made of a material containing (Cr) is laminated in this order; forming a pattern of light shielding portions on the light shielding film; and a pattern of light transmitting portions on the light shielding film and the semitransmissive film. A process of forming a resist film and a pattern of a light transmitting portion formed in the resist film as a mask The semi-transmissive film is then etched by a nonexcited substance comprising a compound of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) with fluorine (F). It is a manufacturing method of the multi-gradation mask characterized by having a process to make.

(Aspect 4)

The step of forming the pattern of the light shielding portion in the light shielding film is performed by wet etching using a resist film having a pattern of the light shielding portion formed on the light shielding film as a mask. The multi-gradation according to any one of aspects 1 to 3 It is a manufacturing method of a mask.

(Aspect 5)

The substance in the non-excited state is a ClF ₃ gas, which is a method for producing a multi-gradation mask according to any one of Aspects 1 to 4, characterized in that.

(Aspect 6)

The metal in the said translucent film is molybdenum (Mo), The manufacturing method of the multi-gradation mask in any one of aspect 1-5 characterized by the above-mentioned.

(Aspect 7)

The said light shielding film consists of a material which contains nitrogen further, The manufacturing method of the multi-gradation mask in any one of aspect 1-6 characterized by the above-mentioned.

(Aspect 8)

The said translucent board | substrate consists of synthetic quartz glass, The manufacturing method of the multi-gradation mask in any one of aspect 1-7 characterized by the above-mentioned.

(Aspect 9)

An etching apparatus used in the method for manufacturing a multi-gradation mask according to any one of aspects 1 to 8, comprising: a chamber having a stage for installing the mask blank, and a non-excited substance supply for supplying a substance in an unexcited state into the chamber; And an gas ejector for discharging gas from the chamber.

According to the method for producing a multi-gradation mask according to the above aspects 1 to 8, the semi-transmissive film has a high etching rate with respect to a material in a non-excited state containing the fluorine-based compound of the present invention. Since the etching rate with respect to the substance in an excited state is significantly low, high etching selectivity is obtained between the translucent substrate and the translucent film. Thereby, when the semi-transmissive film of the part which becomes the light-transmitting part of a multi-gradation mask is etched away from the said non-excited state, and a multi-gradation mask is produced, the CD in-plane uniformity of a semi-transmissive film pattern is compared with the case of wet etching, Can be improved.

In particular, in the case of a semi-transmissive film made of a material containing tantalum, the pit-shaped concave defect occurring on the surface of the substrate can be suppressed after the semi-transmissive film is etched away. Thereby, the in-plane uniformity of the exposure light transmittance of the transmissive part can be made high, and the residual film amount after photoresist film development in the case of exposing and transferring a pattern to the photoresist film of the transfer object using this multi-gradation mask is also highly accurate. Can be controlled by

Moreover, since the etching by the substance of the said non-excited state is applied, the chamber in which etching is performed fully functions as long as it can be set to some low pressure. For this reason, a large chamber for high vacuum, such as a dry etching apparatus, and the large-scale plasma generation apparatus for generating a plasma in the whole surface of a board | substrate main surface are unnecessary, and the production cost can be reduced significantly. Moreover, since a high quality board | substrate can be reproduced with low cost, it is especially suitable for board | substrate regeneration of the multi-gradation mask using the expensive base material with high added value.

Moreover, the manufacturing method of the multi-tone mask which concerns on the said aspect 1-8 can be easily implement | achieved by using the etching apparatus which concerns on the said aspect 9.

1 is a schematic cross-sectional view for explaining a pattern transfer method using a multi-gradation mask.
2 is a schematic cross-sectional view showing a manufacturing process of a multi-gradation mask.
3 is a schematic cross-sectional view showing another embodiment of a manufacturing process of a multi-gradation mask.
4 is a schematic configuration diagram of an etching apparatus used in an etching step of a translucent film.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail.

1 is a schematic cross-sectional view for explaining a pattern transfer method using a multi-gradation mask. The multi-gradation mask 20 shown in FIG. 1 is used for manufacturing FPD devices, such as a thin film transistor (TFT), a color filter, or a plasma display panel (PDP) of a liquid crystal display (LCD), for example. . By using the multi gradation mask 20 to perform pattern transfer on the transfer member 30 shown in FIG. 1, the resist pattern 33 in which the film thickness differs stepwise or continuously can be formed. In addition, in FIG. 1, the code | symbol 32A and 32B represent the film | membrane laminated | stacked on the board | substrate 31 by the to-be-transferred body 30. In addition, in FIG.

Specifically, the multi-gradation mask 20 includes a light shielding portion 21 for shielding exposure light (transmittance of approximately 0%) when the multi-gradation mask 20 is used, and a surface of the translucent substrate 1. And a translucent portion 23 for reducing the transmittance of 10 to 80%, preferably 20 to 60% when the exposure light transmittance of the light transmitting portion is 100%. . The semi-transmissive portion 23 is formed by forming a light semi-transmissive semi-transmissive film 2 on a translucent substrate 1 such as a glass substrate. The light shielding portion 21 is formed by laminating the translucent film 2 and the light shielding film 3 on the light transmissive substrate 1. In addition, the pattern shape of the light shielding part 21, the light transmissive part 22, and the semi-transmissive part 23 shown in FIG. 1 is a typical example only, Of course, it does not mean that this invention is limited to this.

As the semi-transmissive film 2, a material containing metal and silicon (Si), or tantalum (Ta), hafnium (Hf), zirconium (Zr), tungsten (W), zinc (Zn), molybdenum (Mo), Titanium (Ti), vanadium (V), yttrium (Y), rhodium (Rh), niobium (Nb), lanthanum (La), palladium (Pd), iron (Fe), aluminum (Al), germanium (Ge) and A material containing at least one metal selected from tin (Sn) is used. As the light shielding film 3, a material containing chromium (Cr) is used.

In the light shielding portion 21, by selecting the film material and the film thickness of each of the light shielding film 3 and the translucent film 2, preferably in the laminated structure of the light shielding film 3 and the translucent film 2 Is set to 2.8 or more (transmittance with respect to exposure light is about 0.16% or less). Moreover, it is optimal to set the optical density OD in the laminated structure of the light shielding film 3 and the semi-transmissive film 2 to 3.0 or more (transmittance with respect to exposure light is 0.1% or less). The transmittance of the semi-transmissive portion 23 is set by the selection of the film material and the film thickness of the semi-transmissive membrane 2.

In the case where the multicolored light of the ultra-high pressure mercury lamp is used as the light source for exposure transfer using the multi-gradation mask 20 as the light source, the optical density and transmittance of the light shielding portion 21 and the semi-transmissive portion 23 and the like are at least. It is necessary to adjust so that it may become said predetermined | prescribed optical density or transmittance at at least 1 wavelength of i line | wire (wavelength 365nm), h line | wire (wavelength 405nm), and g line | wire (wavelength 436nm) which are peak wavelengths of exposure light. Moreover, it is more preferable to adjust so that it may satisfy | fill predetermined optical density | concentration or the transmittance | permeability of a predetermined range in any wavelength among i line | wire, h line | wire, and g line | wire.

When the multi-gradation mask 20 as described above is used, the exposure light is not substantially transmitted through the light shielding portion 21, and the exposure light is reduced in the semi-transmissive portion 23. For this reason, the resist film (for example, a positive resist film) formed on the to-be-transferred body 30 becomes thick in the part corresponding to the light shielding part 21 when it develops after a transfer, and is semi-permeable. In the portion corresponding to the light portion 23, the film thickness becomes thinner than that, and in the portion corresponding to the light transmitting portion 22, the residual film does not substantially occur, thereby forming a three-gradation resist pattern 33 (FIG. 1). In this resist pattern 33, the effect of thinning the film thickness at the portion corresponding to the translucent portion 23 is called a gray tone effect. In the case of using a negative resist, it is necessary to design in consideration of the inversion of the resist film thickness corresponding to the light shielding portion and the light transmitting portion.

Then, in the portion without the film 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 member 30 so that the film of the resist pattern 33 is thin. The portion is removed by ashing or the like, and at the portion removed by ashing or the like, for example, the film 32B in the transfer object 30 is subjected to a second etching. In this way, the process of two conventional photomasks is performed using the single gradation mask 20, and the number of masks is reduced.

In addition, the multi-gradation mask 20 shown in FIG. 1 has a light shielding portion 21, a light transmitting portion 22, and one semi-light transmitting portion 23 having a predetermined exposure light transmittance on the light transmissive substrate 1. Although it is a three-gradation mask which has the transfer pattern which consists of a several gradation mask, by providing a some semi-transmissive part from which exposure light transmittance differs together with a light shielding part and a light transmission part, it can be set as a mask more four gradations or more.

Next, one aspect of the manufacturing method of the multi-gradation mask which concerns on this invention is demonstrated.

2 is a schematic cross-sectional view showing a process of manufacturing a multi-gradation mask in the order of steps.

In this embodiment, a three-gradation mask including a light shielding portion, a light transmitting portion, and a semi-light transmitting portion as shown in FIG. 1 will be described as an example.

The mask blank 10 used for this embodiment is a material containing a metal and silicon (Si) on the translucent board | substrate 1, or tantalum (Ta), hafnium (Hf), zirconium (Zr), and tungsten ( W), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium (V), yttrium (Y), rhodium (Rh), niobium (Nb), lanthanum (La), palladium (Pd), iron ( Semi-transmissive film 2 made of a material containing at least one metal selected from Fe, aluminum (Al), germanium (Ge), and tin (Sn), and light-shielding film 3 made of a material containing chromium (Cr). ) Are laminated in this order, and a resist film 4 is formed thereon by applying a resist thereon (see FIG. 2A). In this embodiment, the transmittance of the light shielding portion in the three-tone mask to be manufactured is determined by lamination of the light shielding film 3 and the semi-transmissive film 2. By selecting the film material and the film thickness of each of the light shielding film 3 and the semi-transmissive film 2, it is preferable that optical density is set to 2.8 or more as a sum total, and setting to 3.0 or more is optimal. In addition, the transmittance | permeability of the semi-transmissive part in a three-tone mask is set by selection of the film | membrane material and film thickness of the said translucent film 2. Although based on the required design value, when the exposure light transmittance of the transmissive part is 100%, the transmittance of the semi-transmissive part is preferably set to, for example, about 10 to 80%, preferably about 20 to 60%.

The transparent substrate 1 for the mask blank is not particularly limited as long as it has transparency to an exposure wavelength to be used, and is not limited to a synthetic quartz substrate and other glass substrates (for example, soda lime glass, aluminosilicate glass, etc.). ) Is used, but among these, a synthetic quartz substrate is particularly preferably used. In addition, the translucent board | substrate 1 used by a multi-gradation mask blank generally has one side 500 mm or more. In the development, there are various sizes of the short side x long side of the substrate in the range of 500 mm x 800 mm to 2140 mm x 2460 mm, and the thickness also has a size in the range of 10 mm to 15 mm.

In the case where a material containing a metal and silicon (Si) is used for the semi-transmissive film 2, as an applicable metal, Mo, Hf, Zr, Ge, Sn, W, Zn, Ni, Y, Ti, V, Rh, Nb, La, Pd, Fe, Ge, Al, etc. are mentioned. In particular, when Mo, Hf, Zr, W, Ti, V, Nb, and Al are applied, the etching rate at the time of etching the translucent film by the non-excited state containing the fluorine-based compound of the present invention can be raised, Moreover, since the wavelength dependence (especially the wavelength range of i line | wire to g line | wire) of the exposure light transmittance of a semi-transmissive film can be made small, it is preferable. The ratio of the metal (M) and silicon (Si) in the translucent film 2 of these materials is preferably in the range of M: Si = 1: 2 to 1:19. The translucent film 2 is more preferable in order to form a transition metal silicide as long as it is a material containing a transition metal and silicon. In particular, molybdenum (Mo) is preferable among the transition metals. The ratio of molybdenum (Mo) and silicon (Si) in the translucent film 2 of the material containing molybdenum (Mo) and silicon (Si) is preferably in the range of Mo: Si = 1: 2 to 1:19. Do.

Nitrogen may be further contained in the translucent film 2 using the material containing a metal and silicon (Si). By containing nitrogen, the crystal grain diameter of a film | membrane becomes small, a film stress is reduced, and there exists an effect that adhesiveness with the translucent board | substrate 1 improves. When a material containing metal and silicon (Si) contains an element such as nitrogen or carbon, the content of these elements is preferably 40 atomic% or less and 30 atomic% or less. Thereby, the etching rate at the time of etching the translucent film 2 with the substance of the non-excitation state containing the fluorine-type compound of this invention can be raised.

Tantalum (Ta), hafnium (Hf), zirconium (Zr), tungsten (W), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium (V), and yttrium (2) Contains at least one metal selected from Y), rhodium (Rh), niobium (Nb), lanthanum (La), palladium (Pd), iron (Fe), aluminum (Al), germanium (Ge) and tin (Sn) In the case of applying a material to be mentioned, examples of the material include nitrides, oxides, oxynitrides, etc. of the metals alone or alloys, in addition to these metals alone or alloys. Moreover, among the metals shown above, the semitransmissive film 2 contains an alloy of any one metal or any metal selected from these among Ta, Mo, Hf, Zr, W, Ti, V, Nb, and Al. When applied as a metal to be used, the etching rate at the time of etching the translucent film 2 with the substance in the non-excited state containing the fluorine-based compound of the present invention can be further increased, which is preferable.

As a material of the translucent film 2, the material containing tantalum (Ta) is especially preferable. In addition to tantalum alone, tantalum nitride (TaN), tantalum oxide (TaO), tantalum oxynitride (TaNO), and the like, and the like, and materials containing tantalum and at least one element selected from silicon and boron are also preferable. Specifically, materials containing tantalum and silicon include TaSi, TaSiN, TaSiO, TaSiON, and the like. Examples of materials containing tantalum and boron include tantalum, silicon, and boron, such as TaB, TaBN, TaBO, and TaBON. As a material to contain, TaSiB, TaSiBN, TaSiBO, TaSiBON etc. are mentioned.

By containing boron in the material containing tantalum, the wavelength dependence (especially the wavelength region of i-g line | wire) of exposure light transmittance in a semi-transmissive film | membrane becomes small. In this case, it is preferable that content of boron is 40 atomic% or less.

In addition, in the material containing tantalum, when it further contains elements, such as nitrogen and carbon, it is preferable to make content of these elements into 40 atomic% or less and 30 atomic% or less. Thereby, the etching rate at the time of etching the translucent film 2 with the substance of the non-excitation state containing the fluorine-type compound of this invention can be raised.

The light shielding film 3 is made of a material containing chromium (Cr), but as the material, a material containing elements such as nitrogen, oxygen, and carbon in chromium alone, for example, CrN, CrO, CrC, CrON, CrCN, CrOC, CrOCN, etc. are mentioned. In particular, it is preferable to contain nitrogen in the material containing chromium. By containing nitrogen, the etching rate with respect to the etchant used when wet-etching a light shielding film becomes fast. For this reason, when wet-etching a light shielding film using the resist film which has a pattern of the light shielding part formed on the light shielding film as a mask, the etching selectivity of a light shielding film and a semi-transmissive film becomes high, and the damage of the semi-transmissive film under a light shielding film can be suppressed more. Can be. When nitrogen is contained in the light shielding film containing chromium, the content of nitrogen is preferably 15 to 60 atomic%. When content of nitrogen is less than 15 atomic%, the above-mentioned effect is not fully acquired. On the other hand, if it is content exceeding 60 atomic%, when using an ultrahigh pressure mercury lamp as a light source of exposure light, in order to make predetermined optical density in the wavelength band which extends from i line | wire to g line | wire, it is necessary to thicken a film thickness, and The problem that CD precision at the time of forming the pattern of a light part falls is caused. In addition, the CD accuracy at the time of forming the pattern of the semi-transmissive portion using this light shielding film as an etching mask is also lowered.

Next, the manufacturing process of the multi-gradation (three-gradation) mask using the said mask blank 10 is demonstrated.

First, the first drawing is performed. In this embodiment, laser light (for example, predetermined wavelength light in the range of 400-450 nm) is used for drawing. As the resist, a positive resist is used. With respect to the resist film 4 on the light shielding film 3, a predetermined device pattern (a pattern of the light transmitting portion, that is, a drawing pattern for forming a resist pattern in a region corresponding to the light blocking portion and the semi-transmissive portion) is drawn, and the development is performed after drawing. By doing so, a resist pattern 4a having a pattern of the light transmitting portion is formed (see FIG. 2B).

Next, by etching the light shielding film 3 using the resist pattern 4a as a mask, the semi-transmissive film 2 corresponding to the region of the light transmitting part is exposed to form a pattern of the light transmitting part in the light shielding film 3 ( See FIG. 2 (c)). In the case where the light shielding film 3 made of a material containing chromium is used, any of dry etching and wet etching can be used as the etching means, but wet etching was used in the present embodiment. Especially in mask manufacture of a large substrate size, wet etching is preferable. As an etchant used for wet etching, for example, a mixed solution of ammonium dicerium ammonium nitrate and perchloric acid is used. The remaining resist pattern 4a is removed (see FIG. 2 (d)).

Next, using the pattern of the light transmitting portion formed on the light shielding film 3 as a mask, the semi-transmissive film 2 on the exposed light transmitting region is etched to form a light transmitting portion (see FIG. 2E).

In the etching process of such a semi-transmissive film 2, since the pattern of the transmissive part formed in the said light-shielding film 3 is used as an etching mask, the light-shielding film 3 and half with respect to the etchant used for the etching of the semi-transmissive film 2 are used. The etching selectivity between the translucent film 2 is required, and in order to reduce the damage on the surface of the substrate (glass substrate) after the translucent film 2 is removed, the semi-transmissive film 2 is used for etching. The etching selectivity between the translucent film 2 and the translucent substrate 1 with respect to the etchant is also required.

As an etchant used for etching the translucent film 2, a compound of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) with fluorine (F), i.e. The material of the non-excitation state containing the fluorine-type compound of this invention is applied.

As for the substance of the fluorine-based compound of the present invention in a non-excited state, the light shielding film 3 made of a material containing chromium and a material containing metal and silicon, or 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 (Pd) , High etching selectivity can be obtained between the semi-transmissive film 2 made of a material containing at least one metal selected from iron (Fe), aluminum (Al), germanium (Ge), and tin (Sn). .

In addition, the glass substrate used as the light-transmissive substrate 1 has a characteristic of being easily etched in the plasma of the fluorine-based gas in the excited state used in the dry etching, but hardly etched into the substance of the fluorine-based compound of the present invention in the non-excited state. . Therefore, with respect to the substance of the fluorine-based compound of the present invention in the non-excited state, high etching selectivity can be obtained between the glass substrate and the semi-transmissive film 2.

As the fluorine-based compound of the present invention, for example, compounds such as ClF ₃ , ClF, BrF ₅ , BrF, IF ₃ , IF ₅ , or XeF ₂ can be preferably used, and among these, ClF ₃ is particularly preferable. It is available.

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

In the etching process of the said semi-transmissive film 2, as a method of making the semi-transmissive film 2 contact a non-excited state containing the fluorine-type compound of this invention, it is a process substrate (namely, FIG. 2), for example in a chamber. The substrate in the state shown in (d) is referred to as a "processing substrate" for convenience of explanation), and the substance containing the fluorine-based compound of the present invention is introduced into the chamber in a gaseous state, The method of substituting with gas is mentioned preferably.

When a substance containing the fluorine-based compound of the present invention is used in the gas state, the fluorine-based compound and nitrogen gas of the present invention, or argon (Ar), helium (He), neon (Ne), krypton (Kr), xenon (Xe) ) And a mixed gas with a rare gas of radon (Rn) or the like (hereinafter simply referred to as argon (Ar) or the like) can be preferably used.

The processing conditions in the case where the semi-transmissive film 2 of the processing substrate is brought into contact with a non-excited gas-containing substance containing the fluorine-based compound of the present invention, for example, gas flow rate, gas pressure, temperature and processing time, Although it does not need to restrict, it is preferable to select suitably according to the material and film thickness of a translucent film and a light shielding film from a viewpoint which acquires the effect of this invention preferably.

About the gas flow rate, when using the mixed gas of the fluorine-type compound of this invention, argon, etc., for example, it is preferable that the fluorine-type compound of this invention is mixed 1% or more by a flow ratio. 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 translucent film 2 is slowed, and as a result, the processing time is long, and the side etch amount is increased.

In addition, about gas pressure, it is preferable to select suitably in the range of 100-760 Torr, for example. If the gas pressure is lower than the above range, the amount of gas of the fluorine-based compound of the present invention in the chamber itself is too small, so that the progress of etching of the translucent film 2 is slowed, and as a result, the processing time is long and the side etch amount is increased. On the other hand, if the gas pressure is higher than the above range (at least atmospheric pressure), the gas may flow out of the chamber, and the fluorine-based compound of the present invention contains a highly toxic gas, which is not preferable.

In addition, it is preferable to select suitably the temperature of gas in 50-250 degreeC, for example. If the temperature is lower than the above range, the progress of etching of the translucent film 2 is slowed down, and as a result, the processing time is long, and the side etch amount is increased. On the other hand, when the temperature is higher than the above range, the etching proceeds quickly and the processing time can be shortened. However, the selectivity between the translucent film and the substrate is difficult to be obtained, and the substrate damage may be slightly increased.

In addition, about processing time, basically, what is necessary is just enough time for the etching of the translucent film 2 to complete. Although somewhat different depending on the above-described gas flow rate, gas pressure, temperature, or the material and film thickness of the semi-translucent film, the action of the present invention is preferably obtained in the range of approximately 20 seconds to 300 seconds.

4 is a schematic configuration diagram of an etching apparatus suitable for use in the etching step of the semi-transmissive film described above.

In this etching apparatus, the non-excited gas supply is comprised by the gas filling containers 43 and 44, the flow controllers 45 and 46, the blowing nozzle 47, and these connection piping. The processing substrate (mask blank) 41 is provided on the stage 42 in the chamber 40 of the processing apparatus. Then, for example, the gases in the two types of gas filling vessels 43 and 44 are sent to the flow controllers 45 and 46, respectively, and the flow rate is adjusted, followed by mixing, and ejecting from the jet nozzle 47 to form a chamber ( 40). In addition, the gas in the chamber 40 is appropriately exhausted from the exhaust pump (gas exhauster) 49 through the exhaust pipe 48.

The two kinds of gases are fluorine-based compounds, nitrogen gas, and rare gases such as argon (Ar) when the substance containing the fluorine-based compound of the present invention is used in the gas state.

In addition, although the resist pattern 4a was removed at the end of the etching process of the light shielding film 3 before this process, you may perform the etching process of the semi-transmissive film 2, leaving the resist pattern 4a. In this case, the surface of the light shielding film 3 can be protected from being exposed to the substance of the fluorine-type compound in a non-excited state. On the other hand, when removing the resist pattern 4a, since the substance of a fluorine-type compound of a non-excitation state is supplied more uniformly in the main surface, pattern precision can be made higher.

Next, the same resist film is formed on the whole surface of the board | substrate which completed the above-mentioned etching process of the translucent film 2 (when the resist pattern 4a was not removed, it removes before forming a resist film), and the 2nd Draw. In the second drawing, a predetermined pattern is drawn so that a resist pattern is formed on the light shielding region. After drawing, development is performed to form a resist pattern 4b on a region corresponding to the light shielding portion (see FIG. 2 (f)).

Next, using the resist pattern 4b as a mask, the light shielding film 3 on the exposed semi-transmissive portion region is etched to form a pattern corresponding to the light shielding portion on the light shielding film 3. As etching means in this case, wet etching is preferable as before. Thereby, the semi-transmissive part 2 on the semi-transmissive part area | region is exposed, and the semi-transmissive part is formed (refer FIG. 2 (g)). Then, the remaining resist pattern 4b is removed.

In this way, the light shielding part 21 formed by the laminated | multilayer film of the translucent film 2 and the light shielding film 3 on the translucent board | substrate 1, the light transmissive part 22 which the translucent board | substrate 1 is exposed, And a three-tone mask 20 having a translucent portion 23 formed by the translucent film 2 (see FIG. 2H).

According to the method for producing a multi-tone mask described above, a material containing metal and silicon, or tantalum (Ta), hafnium (Hf), zirconium (Zr), tungsten (W), zinc (Zn), molybdenum (Mo), Titanium (Ti), Vanadium (V), Yttrium (Y), Rhodium (Rh), Niobium (Nb), Lanthanum (La), Palladium (Pd), Iron (Fe), Aluminum (A1), Germanium (Ge) and The semi-transmissive film made of a material containing at least one metal selected from tin (Sn) has a high etching rate for a material in a non-excited state (preferably non-excited and gaseous state) containing the fluorine-based compound of the present invention. Since the glass which is a material of a translucent board | substrate has a very low etching rate with respect to the said non-excited state material, high etching selectivity is obtained between a translucent board | substrate and a translucent film. Thereby, when the semi-transmissive film of the part which becomes the light-transmitting part of a multi-gradation mask is etched away from the said non-excited state, and a multi-gradation mask is produced, the CD in-plane uniformity of a semi-transmissive film pattern is compared with the case of wet etching, Can be improved.

In particular, in the case of a semi-transmissive film made of a material containing tantalum, the pit-shaped concave defect occurring on the surface of the substrate can be suppressed after the semi-transmissive film is etched away. Thereby, the in-plane uniformity of the exposure light transmittance of the transmissive part can be made high, and the residual film amount after photoresist film development in the case of exposing and transferring a pattern to the photoresist film of the transfer object using this multi-gradation mask is also highly accurate. Can be controlled by

Moreover, since the etching by the substance of the non-excitation state containing the fluorine-type compound of this invention is applied, the chamber in which etching is performed fully functions as long as it can be set to some low pressure. For this reason, a large chamber for high vacuum, such as a dry etching apparatus, and the large-scale plasma generation apparatus for generating a plasma in the whole surface of a board | substrate main surface are unnecessary, and the production cost can be reduced significantly.

In addition, 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 regeneration cost of the substrate can be reduced by reducing the process load of regrinding. Since a high quality board | substrate can be reproduced at low cost, it is especially preferable to reproduce the board | substrate of a multi-gradation mask using the expensive base material with high added value.

Moreover, by using the above-mentioned etching apparatus, the manufacturing method of the said multi-gradation mask can be implement | achieved easily.

Next, another form of the manufacturing method of the multi-gradation mask which concerns on this invention is demonstrated.

FIG. 3 is a schematic cross sectional view showing a process of manufacturing a multi-gradation mask which is a different process from that shown in FIG. Although the three gradation mask of FIG. 2H and the three gradation mask of FIG. 3F are basically the same configurations, the manufacturing process is partially different.

The difference from the manufacturing method of the multi-gradation mask of FIG. 2 is that the resist pattern 4b having the pattern of the light shielding portion is formed by drawing and developing the first resist film 4 (FIG. 3B). ) To form the pattern of the light shielding portion by etching the light shielding film 3 using the resist pattern 4b as a mask (see (c) of FIG. 3), and also to the light shielding film 3 After the pattern is formed, a resist film is formed on the light shielding film 3 and the semitransmissive film 2, and a resist pattern 4a having a pattern of the light transmitting portion is formed by second drawing and developing (Fig. 3). (d)) and the semi-transmissive film 2 is etched using the resist pattern 4a as a mask to form a pattern of the light transmitting portion (see FIG. 3E).

In the manufacturing process of the multi-gradation mask shown in this FIG. 3, there is a merit that a light shielding part can be formed only by etching the light shielding film 3 once. However, since the pattern of the light transmitting portion is etched and formed on the semitransmissive film 2 using the resist pattern 4a of the organic material as a mask, the light shielding film 3 of the metallic material is used as a mask as in the manufacturing process of FIG. Compared with the case where the pattern of the translucent part is etched and formed in the semi-transmissive film 2, the pattern precision is slightly inferior.

[Example]

Hereinafter, embodiment of this invention is described further more concretely by an Example. In addition, the comparative example with respect to an Example is also demonstrated.

(Example 1)

On a light-transmissive substrate (1220 mm x 1400 mm x 13 mm) made of synthetic quartz glass, using a sputtering device, a mixed sintering target of molybdenum (Mo) and silicon (Si) to a sputter target (Mo: Si = 20: 80) , Atomic percent ratio), and formed into a MoSi ₄ semi-translucent film by reactive sputtering (DC sputtering) in an argon (Ar) gas atmosphere. Moreover, the film thickness was 5 nm so that a transmittance might be 40% in the wavelength of i line | wire (365 nm).

Next, on the semi-translucent film, by using a chromium (Cr) target as a sputter target, in a mixed gas atmosphere of argon (Ar) and nitrogen (N ₂ ), by reactive sputtering (DC sputtering), the film thickness 15 A nm CrN layer was formed. Next, in a mixed gas atmosphere of argon (Ar), methane (CH ₄ ) and nitrogen (N ₂ ), a CrCN layer having a thickness of 65 nm was formed by reactive sputtering (DC sputtering). Next, in a mixed gas atmosphere of argon (Ar) and nitrogen monoxide (NO), a CrON layer having a thickness of 25 nm was formed by reactive sputtering (DC sputtering). Thus, a chromium light shielding film having a total film thickness of 105 nm was formed. The light shielding film is a film having a structure in which each layer is inclined in composition, and is adjusted to have an optical density of 3.0 at a wavelength of i-line (365 nm) in a laminated structure with the semi-transmissive film.

As described above, a mask blank in which a molybdenum silicide-based translucent film and a chromium-based light shielding film were laminated in this order on a light-transmissive substrate was produced.

Next, according to the process of FIG. 2 mentioned above, the three-tone mask was produced using this mask blank.

First, the first drawing was performed using a laser beam (wavelength 412 nm). As the resist, a positive resist was used. With respect to the resist film coated on the light shielding film, a predetermined device pattern was drawn and developed after drawing to form a resist pattern having a pattern of the light transmitting portion (see FIG. 2B).

Next, the light-shielding film was wet-etched using the resist pattern as a mask to expose the semi-transmissive film corresponding to the region of the light-transmitting portion, thereby forming a pattern of the light-transmitting portion on the light-shielding film (see FIG. 2C). As the etching solution, an etching solution containing dicerium ammonium nitrate and perchloric acid was used at room temperature. After the etching, the remaining resist pattern 4a was removed (see FIG. 2 (d)).

Next, the semi-transmissive film on the exposed light-transmitting region was etched using the pattern of the light-transmitting portion formed on the light shielding film as a mask to form a light-transmitting portion with the substrate surface exposed (see FIG. 2E).

This semi-transmissive film was etched using the etching apparatus shown in FIG. 4 described above. That is, a substrate in which a pattern of a light transmitting portion is formed in the light shielding film is provided in the chamber, and a mixed gas of ClF ₃ and Ar (flow ratio ClF ₃ : Ar = 0.2: 0.8 (SLM)) is introduced into the chamber to form a chamber. By replacing with the gas, the semi-transmissive film exposed on the light-transmitting region was brought into contact with the mixed gas in an unexcited state. The gas pressure at this time was adjusted to 488-502 Torr, the temperature to 195-202 degreeC, and the processing time (etching time) was 36 second.

Next, the same positive type resist film was formed on the whole board | substrate surface which finished the above-mentioned etching process of the translucent film, and the 2nd drawing was performed. In the second drawing, a predetermined pattern is drawn so that a resist pattern is formed on the light shielding portion region, and after drawing, development is performed to form a resist pattern on the region corresponding to the light shielding portion (FIG. 2 (f). ) Reference).

Next, using the resist pattern as a mask, the light shielding film on the exposed semi-transmissive part region was wet etched to form a pattern corresponding to the light shielding part in the light shielding film. The etching liquid in this case used the etching liquid similar to the above. As a result, the translucent film on the translucent portion region was exposed to form a translucent portion (see FIG. 2G). And the remaining resist pattern was removed by the same method as before.

In this way, a three-tone mask having a light shielding portion made of a laminated film of a translucent film and a light shielding film, a light transmitting portion exposed to the glass substrate, and a semi-transmissive portion made of the semi-transmissive film was produced on the glass substrate (Fig. 2 (h)).

The surface of the glass substrate of the translucent part region from which the semi-transmissive film was removed by etching with respect to the produced three-gradation mask was observed with the electron microscope, and generation | occurrence | production of deterioration layers, such as the residue of a semi-transmissive film and turbidity, was not confirmed. Although the surface reflectance (200-700 nm) of the glass substrate of the light transmission part area | region was measured, there was no change with the board | substrate before film-forming, and the pit-shaped concave defect was not found, either. The fall of the exposure light transmittance resulting from the surface roughness of the board | substrate was few, and the uniformity of the in-plane exposure light transmittance distribution was also high. It was confirmed that the CD in-plane uniformity of the semi-transmissive portion (the semi-transmissive membrane pattern) was also good.

In addition, since the exposure transfer of the pattern was performed on the photoresist film of the to-be-transferred body by using an ultrahigh pressure mercury lamp as an exposure light source using the produced three-tone mask, it is possible to control the remaining film amount after photoresist film development with high precision. I could confirm it.

In addition, the surface roughness of the main surface of the substrate in the light transmitting portion of the three-tone mask is easily prepared by refining the substrate surface (the final step in the normal polishing process) when reproducing the substrate of the three-tone mask. The level was able to recover the roughness.

(Example 2)

Reactive sputtering (DC) in an argon (Ar) gas atmosphere using a tantalum (Ta) target on a sputtering target using a sputtering device on a light-transmissive substrate (1220 mm x 1400 mm x 13 mm) made of synthetic quartz glass. Sputtering) to form a Ta translucent film. Moreover, the film thickness was 4 nm so that a transmittance might be 40% in the wavelength of i line | wire (365 nm).

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

As described above, a mask blank in which a tantalum semi-transmissive film and a chromium-based light shielding film were laminated in this order on a light-transmissive substrate was produced.

Next, according to the process of FIG. 2 mentioned above, the three-tone mask was produced using this mask blank.

First, the first drawing was performed using a laser beam (wavelength 412 nm). As the resist, a positive resist was used. With respect to the resist film coated on the light shielding film, a predetermined device pattern was drawn and developed after drawing to form a resist pattern having a pattern of the light transmitting portion (see FIG. 2B).

Next, the light-shielding film was wet-etched using the resist pattern as a mask to expose the semi-transmissive film corresponding to the region of the light-transmitting portion, thereby forming a pattern of the light-transmitting portion on the light-shielding film (see FIG. 2C). As the etching solution, an etching solution containing dicerium ammonium nitrate and perchloric acid was used at room temperature. After the etching, the remaining resist pattern 4a was removed (see FIG. 2 (d)).

Next, the semi-transmissive film on the exposed light-transmitting region was etched using the pattern of the light-transmitting portion formed on the light shielding film as a mask to form a light-transmitting portion with the substrate surface exposed (see FIG. 2E).

This semi-transmissive film was etched using the etching apparatus shown in FIG. 4 described above. That is, a substrate in which a pattern of a light transmitting portion is formed in the light shielding film is provided in the chamber, and a mixed gas of ClF ₃ and Ar (flow ratio ClF ₃ : Ar = 0.2: 1.8 (SLM)) is introduced into the chamber to provide the inside of the chamber. By replacing with the gas, the semi-transmissive film exposed on the light-transmitting region was brought into contact with the mixed gas in an unexcited state. The gas pressure at this time was adjusted to 488-502 Torr, the temperature to 110-120 degreeC, and the processing time (etching time) was 32 second.

Next, the same positive type resist film was formed on the whole board | substrate surface which finished the above-mentioned etching process of the translucent film, and the 2nd drawing was performed. In the second drawing, a predetermined pattern is drawn so that a resist pattern is formed on the light shielding portion region, and after drawing, development is performed to form a resist pattern on the region corresponding to the light shielding portion (FIG. 2 (f). ) Reference).

Next, using the resist pattern as a mask, the light shielding film on the exposed semi-transmissive part region was wet etched to form a pattern corresponding to the light shielding part in the light shielding film. The etching liquid in this case used the etching liquid similar to the above. As a result, the translucent film on the translucent portion region was exposed to form a translucent portion (see FIG. 2G). And the remaining resist pattern was removed by the same method as before.

In this way, on the glass substrate, a three-tone mask having a light shielding portion formed by the laminated film of the translucent film and the light shielding film, a light transmitting portion exposed by the glass substrate, and a semi-transmissive portion formed by the semitransmissive film was produced. (See Figure 2 (h)).

The surface of the glass substrate of the translucent part region from which the semi-transmissive film was removed by etching with respect to the produced three-gradation mask was observed with the electron microscope, and generation | occurrence | production of deterioration layers, such as the residue of a semi-transmissive film and turbidity, was not confirmed. Moreover, although the surface reflectance (200-700 nm) of the glass substrate of the light transmission part area | region was measured, there was no change compared with the board | substrate before film-forming, and the pit-shaped concave defect was not found, either. The fall of the exposure light transmittance resulting from the surface roughness of the board | substrate was few, and the uniformity of the in-plane exposure light transmittance distribution was also high. It was confirmed that the CD in-plane uniformity of the semi-transmissive portion (the semi-transmissive membrane pattern) was also good.

In addition, since the exposure transfer of the pattern was performed on the photoresist film of the to-be-transferred body by using the produced three gradation mask by using an ultrahigh pressure mercury lamp as an exposure light source, the remaining film amount after photoresist film development can also be controlled with high precision. I could confirm that.

In addition, the surface roughness of the main surface of the substrate in the light transmitting portion of the three-tone mask is easily prepared by refining the substrate surface (the final step in the normal polishing process) when reproducing the substrate of the three-tone mask. The level was able to recover the roughness.

(Comparative Example 1)

A three gradation mask was produced using the same mask blank as in Example 2. However, in the process of etching the semi-transmissive film on the exposed light-transmitting area using the pattern of the light-transmitting part formed in the light-shielding film mentioned above as a mask, sodium hydroxide solution (concentration 40wt%, temperature 70 degreeC) was used as etching liquid. Treatment time (etching time) was 10 minutes.

Processes other than this were performed like Example 1, and the three-tone mask was produced.

When the surface of the glass substrate of the translucent part area | region in the produced three-gradation mask was observed with the electron microscope, the residue of the translucent film was not observed in particular. Moreover, although the surface reflectance (200-700 nm) of the board | substrate was measured, compared with the board | substrate before film-forming, the reflectance fell slightly overall. As a result of observing the surface roughness of the substrate of the light transmitting portion with an atomic force microscope (AFM), it was confirmed that a large number of pit-shaped recesses were formed on the substrate surface of the light transmitting portion. It was confirmed that CD in-plane uniformity of the semi-transmissive portion (semi-transmissive membrane pattern) was lower than that in Example 2.

In addition, the exposure light transmission amount of a pattern was formed in the photoresist film of the transfer object using a manufactured three-tone mask, using an ultrahigh pressure mercury lamp as an exposure light source, and performing exposure transfer of a pattern, particularly in a portion where a pit-shaped recess was formed. It was a result that it was hard to say that the fall of was large and control of the residual film amount after photoresist film image development was also possible.

In addition, the surface roughness of the main surface of the substrate in the translucent portion of the three-tone mask, when regenerating the substrate of the three-tone mask, removes the pit-shaped recesses by regrinding the substrate surface to restore good surface roughness. In order to do this, it is necessary to perform regrinding from the first stage in the substrate polishing process before normal film formation, which increases the process load of repolishing.

In addition, the three gradation masks produced in Example 1 and Example 2 were produced also by the manufacturing method which has the other form process shown in FIG. 3, The three gradations produced in Example 1 and Example 2 Although the CD did not have high in-plane uniformity of the semi-transmissive portion as compared with the mask, it was confirmed that the CD in-plane uniformity of the semi-transmissive portion was higher as compared with the three-tone mask produced in Comparative Example 1. In addition, no pit-shaped concave defects were found on the substrate surface of the light-transmitting portion, the decrease in the exposure light transmittance due to the surface roughness of the substrate was small, and it was confirmed that the uniformity of the in-plane exposure light transmittance distribution was also high.

1: translucent substrate
2: translucent film
3: shading film
4: resist film
10: mask blank
20: multi gradation mask
21: light shield
22: floodlight
23: translucent part
30: subject
31: Substrate
32A, 32B: Membrane
33: resist pattern
40: chamber
41: processing substrate
42: stage
43, 44: gas filling container
45, 46: flow controller
47: jet nozzle
48: exhaust pipe
49: exhaust pump

Claims (11)

A manufacturing method of a multi-gradation mask having a transfer pattern composed of a light shielding portion, a light transmitting portion, and a semi-transmissive portion that transmits a part of exposure light, on a light transmitting substrate,
On the light-transmissive substrate, a material containing metal and silicon, or tantalum (Ta), hafnium (Hf), zirconium (Zr), tungsten (W), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium Selected from (V), yttrium (Y), rhodium (Rh), niobium (Nb), lanthanum (La), palladium (Pd), iron (Fe), aluminum (Al), germanium (Ge) and tin (Sn) A step of preparing a mask blank in which a semi-transmissive film made of a material containing at least one metal and a light shielding film made of a material containing chromium (Cr) are laminated in this order;
Forming a pattern of a light transmitting portion in the light shielding film;
The semi-transmissive film is a compound of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) and fluorine (F) by using the pattern of the light transmitting portion formed on the light shielding film as a mask. Etching with a material in a non-excited state to include,
Forming a pattern of the light blocking portion on the light blocking film
The manufacturing method of the multi-gradation mask characterized by having. The method of claim 1,
A step of forming a pattern of light shielding portions in the light shielding film is performed by wet etching using a resist film having a pattern of light shielding portions formed on the light shielding film as a mask. The method of claim 1,
The step of forming the pattern of the light transmitting portion in the light shielding film is performed by wet etching using a resist film having a pattern of the light transmitting portion formed on the light shielding film as a mask. The method of claim 3,
A step of forming a pattern of light shielding portions in the light shielding film is performed by wet etching using a resist film having a pattern of light shielding portions formed on the light shielding film as a mask. A manufacturing method of a multi-gradation mask having a transfer pattern composed of a light shielding portion, a light transmitting portion, and a semi-transmissive portion that transmits a part of exposure light, on a light transmitting substrate,
On the light-transmissive substrate, a material containing metal and silicon, or tantalum (Ta), hafnium (Hf), zirconium (Zr), tungsten (W), zinc (Zn), molybdenum (Mo), titanium (Ti), vanadium Selected from (V), yttrium (Y), rhodium (Rh), niobium (Nb), lanthanum (La), palladium (Pd), iron (Fe), aluminum (Al), germanium (Ge) and tin (Sn) A step of preparing a mask blank in which a semi-transmissive film made of a material containing at least one metal and a light shielding film made of a material containing chromium (Cr) are laminated in this order;
Forming a pattern of a light shielding portion in the light shielding film;
Forming a resist film having a pattern of a light transmitting portion on the light shielding film and the translucent film;
A compound of any one of chlorine (Cl), bromine (Br), iodine (I), and xenon (Xe) with fluorine (F) is used as the mask using the pattern of the light transmitting portion formed in the resist film as a mask. And a step of etching with a material in an unexcited state comprising a. The method of claim 5,
A step of forming a pattern of light shielding portions in the light shielding film is performed by wet etching using a resist film having a pattern of light shielding portions formed on the light shielding film as a mask. The method according to any one of claims 1 to 6,
The non-excited substance is ClF ₃ gas, characterized in that the manufacturing method of the multi-tone mask. The method according to any one of claims 1 to 6,
The metal in the said translucent film is molybdenum (Mo), The manufacturing method of the multi-gradation mask characterized by the above-mentioned. The method according to any one of claims 1 to 6,
The light shielding film is made of a material further containing nitrogen. The method according to any one of claims 1 to 6,
The translucent substrate is a method of manufacturing a multi-gradation mask, characterized in that made of synthetic quartz glass. As an etching apparatus used in the manufacturing method of the multi-gradation mask in any one of Claims 1-6,
A chamber having a stage for installing the mask blank,
A non-excited material supplier for supplying a material in an unexcited state into the chamber;
A gas exhauster which exhausts gas from within the chamber
Etching apparatus comprising a.

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