KR20070100572A - Half-tone phase shift blankmask and half-tone phase shift mask and their manufacturing method - Google Patents

Abstract

A half tone type phase shift blank mask, a half tone type phase shift mask, and a manufacturing method thereof are provided to adjust a phase shift by applying a transparent film having high selectivity to a transparent substrate and a phase shift film to etch the phase shift film without the damage of the transparent substrate. A half tone type phase shift blank mask includes a transparent substrate(10), a transparent film(20), a phase shift film(30), a light blocking film(40), an anti-reflection film(50), and a resist film(60). The transparent substrate is made of synthetic quartz. The transparent film is formed on the transparent substrate, and is made of CrCON having a thickness of 10~500Å and a transmissivity of 10~90% in an exposure wavelength of 248nm. The phase shift film is formed on the transparent film, and is made of MoTiSiN having the thickness of 300~1000Å and the transmissivity of 10~90% in the exposure wavelength of 248nm. The light blocking film is formed on the phase shift film, and is made of CrCN. The anti-reflection film is formed on the light blocking film, and is made of CrCON. The resist film is formed on the anti-reflection film, and has a thickness of 2000~4000Å.

Description

Half-tone phase shift blank mask and half-tone phase shift mask and their manufacturing method

1 is a cross-sectional view of a halftone phase shift mask manufactured by a conventional technique.

2 is a cross-sectional view of a halftone phase inversion blank mask manufactured by the present invention.

3 is a cross-sectional view of a halftone phase shift mask manufactured by using the halftone phase shift blank mask of FIG. 2.

<Description of Symbols for Major Parts of Drawings>

10: transparent substrate 20: transparent film

30: phase inversion film 40: light shielding film

50: antireflection film 60: resist film

20a: transparent film pattern 30a: phase inversion film pattern

40a: Light shielding film pattern 50a: Antireflection film pattern

100: halftone phase inversion blank mask

200: halftone phase shift mask 300: undercut area

500: sidewall of the phase shift film pattern

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a halftone phase inversion blank mask and a photomask used in the manufacture of semiconductor integrated circuits. In particular, the present invention relates to a halftone phase inversion blank mask and a phase inversion mask that can realize excellent resolution with an excellent selection ratio for a transparent substrate. It is about.

Due to the high integration of semiconductor integrated circuits, halftone phase inversion masks are used in semiconductor photolithography processes. The halftone phase inversion mask is manufactured through a halftone blank mask, and generally has a structure in which a resist film is formed after a phase inversion film pattern, a light shielding film, and an antireflection film are formed on a transparent substrate. In this case, a transparent substrate is typically a quartz substrate mainly composed of SiO ₂ , and a phase inverted layer is also used. The phase inverted layer has a composition of MoSiN or MoSiON or MoSiCON or MoSiCN.

In general, when forming a photomask phase shift film pattern in the manufacture, the light-shielding film and antireflective film of chromium compound as a masking (Masking) and using the gas of the fluorine series, such as He and SF ₆ or CF _4, or CHF ₃ dry Dry Etch is performed. The fluorine-based gas removes Si by physical or chemical reaction. However, since both the transparent substrate and the phase shift film have Si as a main component, it is difficult to set the phase shift time of the phase shift film during dry etching. Due to the above problems, a technique using an end point detector is being applied, but even if dry etching of the phase inversion film is performed using the etch stop detector, it is difficult to etch the phase inversion film without damaging the transparent substrate. As a result, a change in the phase inversion angle that has been measured when the phase inversion film is formed leads to difficulty in manufacturing the phase inversion mask.

Referring to FIG. 1, in the case of a conventional phase inversion mask 200, phase inversion is performed using a phase inversion film pattern 30a, a light shielding film pattern 40a, and an anti-reflection film pattern 50a formed on the transparent substrate 10. The effect was applied. However, as the integration of semiconductor circuits is required, formation of finer patterns is required in the phase inversion mask, and in the case of the conventional phase inversion mask, the intensity of transmitted light is weakened in the region of the sidewall 500 of the phase inversion film pattern 30a. Will occur. As a result, the intensity of transmitted light is weakened, so that the effect of phase inversion due to destructive interference does not sufficiently occur, thereby making it difficult to form a fine pattern.

The present invention is to solve the above problems, an object of the present invention is to increase the intensity of transmitted light generated in the sidewall region of the phase inversion pattern in the halftone phase inversion mask to enhance the phase inversion function through a sufficient offset effect In addition, by adding a thin film such as a transparent film that can improve the selectivity between the transparent substrate and the phase inversion film in the halftone phase inversion blank mask, the selectivity of the phase inversion film with the transparent substrate is improved by improving the selectivity with The purpose is to provide a halftone phase inversion mask.

The halftone phase inversion blank mask and the halftone phase inversion mask according to the present invention for achieving the above object are a halftone phase inversion blank in which a transparent film, a phase inversion film, a light shielding film, an antireflection film, and a resist film are sequentially formed on a transparent substrate. A mask is used to form a phase inversion mask on which a transparent film, a phase inversion film, a light shielding film, and an antireflection film pattern are formed on a transparent substrate.

In particular, in the case of the half-tone phase inversion blank mask manufacturing process according to the present invention, preferably, a1) forming a transparent film on the transparent substrate; b1) forming a phase inversion film on the transparent film formed in step a1); c1) forming a light shielding film on the phase inversion film formed in step b1); d1) forming an anti-reflection film on the light shielding film formed in step c1); e1) forming a resist film on the anti-reflection film formed in step d1) to manufacture a halftone phase inversion blank mask.

The method for forming the transparent film in step a1) may be formed through physical vapor deposition (PVD), chemical vapor deposition (CVD), thermal evaporation, or the like. .

Target materials used in forming the transparent film in step a1) include boron (B), carbon (C), magnesium (Mg), aluminum (Al), silicon (Si), scandium (Sc), and titanium (Ti). , Vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge) , Arsenic (As), yttrium (Y), zirconium (Zr), niobium (Nb), molybdenum (Mo), technetium (Tc), ruthenium (Ru), rhodium (Rh), palladium (Pd), silver (Ag) , Cadmium (Cd), Indium (In), Tin (Sn), Antimony (Sb), Lutetium (Lu), Hafnium (Hf), Tantalum (Ta), Tungsten (W), Rhenium (Re), Osmium (Os) At least one material selected from iridium (Ir), platinum (Pt), gold (Au), thallium (Tl), and lead (Pb) may be used.

When the transparent film is formed through sputtering in the step a1), the process conditions are preferably in the range of 1 × 10 ⁻¹ to 9.9 × 10 ⁻⁵ torr and a voltage of 0.01 to 10 kW.

When the transparent film is formed in the step a1) through sputtering, argon (Ar), which is an inert gas, is used in an amount of 1 to 100 sccm, and nitrogen (N ₂ ), oxygen (O ₂ ), and carbon (C) are used as the reactive gas. , At least one selected from fluorine (F ₂ ) can be used.

In the a1) step, the transmittance at the exposure wavelength of the transparent film is 0 to 90%, and the material of the transparent film is an etching gas capable of dry etching the transparent substrate in consideration of the selectivity with the transparent substrate during dry etching. It is preferable that the material is durable.

When the material of the transparent substrate in step a1) is synthetic quartz, soda lime glass, etc., the main component of the material of the transparent film is preferably chromium.

In the step a1), the material of the transparent film is preferably a material that is not etched by the etching gas used in the dry etching of the phase inversion film.

As a method for forming the phase inversion film in step b1), it may be formed through physical vapor deposition (PVD), chemical vapor deposition (CVD), thermal evaporation, or the like. Can be.

Target materials used in forming the phase inversion film in step a1) include boron (B), carbon (C), magnesium (Mg), aluminum (Al), silicon (Si), scandium (Sc), and titanium (Ti). ), Vanadium (V), chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), gallium (Ga), germanium (Ge) ), Arsenic (As), Yttrium (Y), Zirconium (Zr), Niobium (Nb), Molybdenum (Mo), Technetium (Tc), Ruthenium (Ru), Rhodium (Rh), Palladium (Pd), Silver (Ag) ), Cadmium (Cd), indium (In), tin (Sn), antimony (Sb), lutetium (Lu), hafnium (Hf), tantalum (Ta), tungsten (W), rhenium (Re), osmium (Os) ), One or more materials selected from iridium (Ir), platinum (Pt), gold (Au), thallium (Tl), and lead (Pb) may be used.

Process conditions in the case of forming through the sputtering when the phase inversion film is formed in step a1), the pressure is 1 × 10 ^-1 ~ 9.9 × 10 ^-5 torr, the voltage is preferably 0.01 ~ 10 kW.

When the phase inversion film is formed through the sputtering in the step a1), 1 to 100 sccm of argon (Ar), which is an inert gas, is used, and nitrogen (N ₂ ), oxygen (O ₂ ), and carbon (C) are used as reactive gases. ), And is preferably formed using at least one reactive gas selected from fluorine (F ₂ ).

In the step b1), the transmittance of the phase inversion film is preferably 0.01 to 90% at the exposure wavelength. When the main component of the phase inversion film is a combination of molybdenum and silicon, it may be MoSiN, MoSiON, MoSiCN, or MoSiCON.

In the transparent film and the phase inversion film of steps a1) and b1), the phase inversion of the exposure light preferably has a sum of the phase inversions of each of the transparent film and the phase inversion film is 160 to 200 degrees.

In the step b1), the material of the phase inversion film is preferably a material in which the material of the phase inversion film is not wet etched by the wet etchant used during the wet etching of the transparent film.

In step c1), the transmittance at the exposure wavelength of the light shielding film is preferably less than 1%, and in step d1), the reflectance of the antireflection film is preferably less than 20% at the exposure wavelength.

In the steps a1), c1) and d1), the transparent film, the light shielding film, and the anti-reflection film are preferably materials that are etched in the same etchant during wet etching.

In the step e1), the resist film may be a resist film formed through positive and negative photoresist, electron beam resist, and chemically amplified resist. Can be.

In particular, in the case of the halftone phase shift mask manufacturing method using the halftone phase shift blank mask manufactured by the present invention, f1) exposing the resist film of the halftone phase shift blank mask using an exposure apparatus. ; g1) exposing the resist film in step f1) and then performing post exposure bake (PEB); h1) forming a resist film pattern by performing PEB after the step of f1); i1) etching the anti-reflection film and the light shielding film using the resist film pattern obtained by the development in the step h1) as a mask to form the anti-reflection film and the light shielding film pattern; j1) forming a phase shift film pattern by etching the phase shift film after forming the anti-reflection film and the light shielding pattern in step i1); k1) forming a phase inversion film pattern in step j1) and performing stripping on the resist film pattern that is no longer needed; l1) performing a cleaning to remove foreign substances after stripping the resist film pattern in step k1); m1) forming a resist film after cleaning to remove foreign substances in step l1); n1) exposing the resist film formed in step m1) to a desired area using an exposure apparatus; o1) performing PEB after exposing the resist film in step n1); p1) forming a resist film pattern by performing PEB after the step of o1); q1) forming a transparent film, a light shielding film, and an anti-reflection film pattern by performing etching by masking the resist film pattern formed in step p1); r1) performing a strip of the resist film pattern that is no longer needed after the transparent film, the light shielding film, and the anti-reflection film pattern are formed in the step q1); s1) after performing the stripping of the resist film pattern in the step r1), it may include the step of cleaning to remove the foreign matter.

Through the above process, the halftone phase inversion blank mask and the halftone phase inversion mask according to the present invention were prepared. Hereinafter, the present invention will be described in detail with reference to examples, but the examples are used only for the purpose of illustration and explanation of the present invention, and are used to limit the scope of the present invention as defined in the meaning or claims. no. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible from the embodiments. Therefore, the true technical protection scope of the present invention will be defined by the technical details of the claims.

<Example>

2 is a cross-sectional view showing a halftone phase inversion blank mask manufactured by an embodiment of the present invention. At this time, in the following description, the same or equivalent parts are denoted by the same reference numerals, and the description thereof is omitted.

Referring to the drawings, using a DC magnetron sputter and a chromium target on a transparent substrate 10 made of synthetic quartz and having a surface area of 6 × 6 inches and a thickness of 0.25 inches, an exposure wavelength of 10 to 500 Hz and a wavelength of 248 nm The transparent film 20 of chromium nitride chromium carbide (CrCON) having a transmittance of 10 to 90% at was formed.

Next, using a MoTiSi target on the transparent film 20 and using a DC magnetron sputtering method, a molybdenum nitride titanium silicide (MoTiSiN) film having a thickness of 300 to 1,000 mW and a transmittance of 10 to 90% at an exposure wavelength of 248 nm ( 30) was formed.

Next, after the transparent film 20 and the phase inversion film 30 are formed, phase inversion by the transparent film 20 and the phase inversion film 30 is carried out using MPM-248 of Japan Lasertec Co., Ltd. at an exposure wavelength of 248 nm. As a result, the phase inversion of 160 ~ 200 degrees was shown.

Next, a light shielding film 40 of chromium nitride (CrCN) is formed on the phase shifting film 30 using the same method used to form the transparent film 20 and the phase shifting film 30, and then on the light shielding film 40 An anti-reflection film 50 of chromium nitride oxide chromium carbide (CrCON) was formed.

Next, a resist film 60 having a thickness of 2000 to 4000 GPa was formed using FEP-171 of Fujifilm, Japan, which is a positive chemically amplified resist.

Through the above process, the halftone phase inversion blank mask 100 according to the present invention was manufactured.

FIG. 3 shows a halftone phase shift mask 200 fabricated using the halftone phase shift blank mask 100 (see FIG. 2) manufactured by the present invention.

Referring to the drawings, after exposure to a desired region of the resist film (60, see Fig. 2) using an electron beam exposure equipment commonly used in the manufacture of photomask, after the exposure exposure baking process is applied, The resist film 60 pattern was formed.

Next, the resist film 60 pattern was masked and dry etching using chlorine (Cl ₂ ) gas was performed to form the light shielding film pattern 40a and the antireflection film pattern 50a.

Next, the light shielding film pattern 40a, the antireflection film pattern 50a, and the resist film pattern (not shown) are masked, and dry etching using sulfur hexafluoride (SF ₆ ) gas is performed to perform phase inversion film pattern 30a. Formed. At this time, the CrCON film, which is the transparent film 20, was not etched during the dry etching of the phase inversion film 30, and thus the selectivity was excellent.

Next, after removing the unnecessary resist film 60 pattern by using sulfuric acid, the THMR-iP3600 manufactured by TOK, a positive photoresist, was formed again to form a resist film 60 with a thickness of 3,000 to 6,000 kPa. The exposure apparatus was exposed to a region where a pattern was to be formed, and a developing step was performed to form a resist film 60 pattern.

Next, a transparent etching pattern 20a, a light shielding film pattern 40a, and an antireflection film pattern 50a were formed by using a wet etching process to mask the resist film 60 pattern. At this time, the transparent substrate 10 is not etched by the transparent film pattern 20a, the light shielding film pattern 30a, and the anti-reflection film pattern 40a. The phase inversion film 30 is also used for pattern formation. It was not etched by Therefore, it was confirmed that the selectivity in each of the transparent substrate 10 and the phase inversion film 30 with respect to the transparent film 20 was excellent. In addition, the transparent film pattern 20a was confirmed to have an undercut region 300 formed under the phase inversion film 30 by anisotropy during wet etching.

Next, the unnecessary resist film pattern was removed using sulfuric acid, and the transparent film pattern 20a and the phase inversion film pattern in which the undercut region 300 was formed on the transparent substrate 10 by performing a cleaning process to remove foreign substances. 30a and a phase inversion mask 200 in which the light shielding film pattern 40a was formed were manufactured.

According to the invention of the present embodiment as described above, by forming a transparent film having excellent selectivity for each of the transparent substrate and the phase inversion film, it is possible to preserve the phase inversion amount formed during the manufacture of the phase inversion blank mask, and thus has a high quality half. It is possible to manufacture a tone type phase inversion mask. The half-tone phase shift mask maximizes the phase shift effect without reducing the transmitted light generated on the sidewall of the conventional phase shift pattern by forming an undercut by forming a transparent film that can be etched with a wet etching solution of the same series as the light shielding or antireflection film. Can be manufactured. Therefore, a high quality halftone phase shift mask can be manufactured by manufacturing the halftone phase shift blank mask according to the present invention, and as a result, a semiconductor circuit having excellent integration and high quality can be manufactured.

The halftone phase inversion blank mask and the halftone phase inversion mask according to the present invention are applied to the transparent substrate and the phase inversion film when the halftone phase inversion blank mask is manufactured by applying a transparent film having excellent selectivity to the phase without damaging the transparent substrate. The inversion film can be etched, allowing accurate phase inversion to be controlled.

In addition, since the transparent film is etched by the same wet etchant as the light shielding film and the anti-reflection film, an undercut is formed, thereby maximizing phase inversion without reducing the intensity of transmitted light on the sidewall of the phase shift pattern, thereby providing a high quality halftone phase. Through the manufacture of the inversion mask it is possible to manufacture a high quality semiconductor device.

Claims (11)

In a halftone phase inversion blank mask comprising a transparent film, a phase inversion film, a light shielding film, an antireflection film, and a resist film on a transparent substrate, and having a transmittance of 1% or more at a wavelength of exposure light and a phase inversion of 160 to 200 degrees. The transparent film has a thickness of 10 to 500 kHz, and has a transmittance of 10 to 90% at the wavelength of the exposure light. The method of claim 1, The transparent film is a half-tone phase inversion blank mask, characterized in that the etching is not etched in the dry etching gas containing fluorine. The method of claim 2, The dry etching gas containing fluorine is SF ₆ or CF ₄ or CHF ₃ Halftone phase inversion blank mask, characterized in that. The method of claim 1, The transparent film is a halftone phase inversion blank mask, characterized in that the material of the same series as the light shielding film and the anti-reflection film. The method of claim 4, wherein The material constituting the transparent film, the light shielding film, and the anti-reflection film is at least one selected from chromium-based oxides, nitrides, and carbides. The method of claim 1, The phase inversion film is a halftone phase inversion blank mask, characterized in that at least one selected from the group consisting of oxides, nitrides, carbides based on a material mixed with silicon and transition metal. The method of claim 1, The transparent film is a half-tone phase inversion blank mask, characterized in that the etching by the dry gas used in the dry etching of the phase inversion film. The method of claim 1, The phase inversion mask is a halftone phase inversion blank mask, characterized in that the phase of the exposure light passing through the transparent film and the phase inversion film is inverted by 160 to 200 degrees. A transparent film having a thickness of 10 to 500 위에 on the transparent substrate and having a transmittance of 10 to 90% at the wavelength of the exposure light is formed, thereby forming a transparent film, wherein an undercut is formed by wet etching during the manufacture of the halftone phase inversion mask. Making; And A method of manufacturing a halftone phase inversion blank mask comprising the steps of sequentially forming a phase inversion film, a light shielding film, an antireflection film, and a resist film on a transparent film. The method according to any one of claims 1 to 8, The halftone phase shift mask according to claim 1, wherein the halftone phase shift blank mask is wet-etched to form an undercut. A method of manufacturing a halftone phase shift mask according to claim 9, wherein the halftone phase shift mask is manufactured using a halftone phase shift mask.

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