TW202141172A - Photomask blank and method of manufacturing photomask, and method of manufacturing display device - Google Patents

Photomask blank and method of manufacturing photomask, and method of manufacturing display device Download PDF

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TW202141172A
TW202141172A TW110109475A TW110109475A TW202141172A TW 202141172 A TW202141172 A TW 202141172A TW 110109475 A TW110109475 A TW 110109475A TW 110109475 A TW110109475 A TW 110109475A TW 202141172 A TW202141172 A TW 202141172A
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light
layer
film
shielding film
photomask
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TW110109475A
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Chinese (zh)
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安森順一
浅川敬司
田辺勝
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日商Hoya股份有限公司
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    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03FPHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/54Absorbers, e.g. of opaque materials
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03FPHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/26Phase shift masks [PSM]; PSM blanks; Preparation thereof
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03FPHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/38Masks having auxiliary features, e.g. special coatings or marks for alignment or testing; Preparation thereof
    • G03F1/46Antireflective coatings
    • GPHYSICS
    • G03PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03FPHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F1/00Originals for photomechanical production of textured or patterned surfaces, e.g., masks, photo-masks, reticles; Mask blanks or pellicles therefor; Containers specially adapted therefor; Preparation thereof
    • G03F1/68Preparation processes not covered by groups G03F1/20 - G03F1/50
    • G03F1/80Etching

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Preparing Plates And Mask In Photomechanical Process (AREA)

Abstract

The present invention provides a photomask blank capable of manufacturing a photomask having the following optical properties. The above-mentioned optical properties include an excellent precision in patterning a light-blocking film can realize a higher pattern accuracy when the pattern is transferred by exposure. The photomask blank of the present invention is used when manufacturing the photomask for manufacturing a display device and includes a transparent substrate and a light-blocking film disposed on the transparent substrate. The light-blocking film includes a first reflection-suppressing layer, a light-blocking layer, and a second reflection-suppressing layer in a sequence from the side of the transparent substrate. The first reflection-suppressing layer includes a first low chromium oxide layer having a relatively low ratio of oxygen to nitrogen and a first high chromium oxide layer having a relatively high ratio of oxygen to nitrogen in a sequence from the side of the transparent substrate. The second reflection-suppressing layer includes a second low chromium oxide layer having a relatively low ratio of oxygen to nitrogen and a second high chromium oxide layer having a relatively high ratio of oxygen to nitrogen in a sequence from the side of transparent substrate. The composition and film thickness of the first reflection-suppressing layer, the light-blocking layer, and the second reflection-suppressing layer are set so that the reflectance of the front and back surfaces of the light-blocking film with respect to the exposure wavelength of the exposure light from 300 nm to 436 nm is 15% or less and the optical density is 3.0 or more. The first reflection-suppressing layer and the second reflection-suppressing layer contain carbon, respectively. The method for manufacturing a photomask comprises the steps of preparing a photomask blank, forming a resist film on the light-blocking film, etching the light-blocking film by using the resist pattern formed by the resist film as a mask, and forming a light- blocking film pattern on the transparent substrate.

Description

光罩基底及光罩之製造方法、以及顯示裝置之製造方法Mask base and mask manufacturing method, and display device manufacturing method

本發明係關於一種光罩基底及光罩之製造方法、以及顯示裝置之製造方法。The present invention relates to a manufacturing method of a photomask substrate and a photomask, and a manufacturing method of a display device.

於以LCD(Liquid Crystal Display,液晶顯示器)為代表之FPD(Flat Panel Display,平板顯示器)等顯示裝置中,大畫面化、廣視角化以及高精細化、高速顯示化急速發展。實現該高精細化、高速顯示化所必需之要素之一係製作微細且尺寸精度較高之元件或配線等電子電路圖案。該顯示裝置用電子電路之圖案化大多使用光微影法。因此,需要形成有微細且高精度之圖案之顯示裝置製造用之光罩。In display devices such as FPD (Flat Panel Display) represented by LCD (Liquid Crystal Display), large screens, wide viewing angles, high-definition, and high-speed displays are rapidly developing. One of the elements necessary to realize this high-definition and high-speed display is the production of electronic circuit patterns such as components or wirings with fine and high dimensional accuracy. The patterning of the electronic circuit for the display device mostly uses the photolithography method. Therefore, there is a need for a mask for manufacturing display devices with fine and high-precision patterns formed.

顯示裝置製造用光罩係由光罩基底製作。光罩基底係於包含合成石英玻璃等之透明基板上設置由對曝光之光不透明之材料製成之遮光膜而構成。例如,如專利文獻1所示,於光罩基底或光罩中,為了抑制使用光罩對被轉印體之面板進行曝光時來自被轉印體之反射光於光罩表面反射並再次反射至被轉印體,而於遮光膜之正反兩面側設置抗反射膜,光罩基底例如成為如下膜構成,即,自透明基板側起依序積層有背面抗反射膜、遮光膜、反射衰減膜及抗反射膜。光罩係藉由利用濕式蝕刻等使構成光罩基底之各膜圖案化而形成特定遮光膜圖案來製作。 [先前技術文獻] [專利文獻]The photomask for manufacturing the display device is made from the photomask substrate. The mask base is formed by arranging a light-shielding film made of a material that is opaque to exposure light on a transparent substrate including synthetic quartz glass and the like. For example, as shown in Patent Document 1, in a photomask base or a photomask, in order to suppress the use of the photomask to expose the panel of the transferee, the reflected light from the transferee is reflected on the surface of the photomask and reflected again to the surface of the photomask. To be transferred, anti-reflection films are provided on the front and back sides of the light-shielding film, and the mask base is composed of, for example, the following film composition, that is, a back anti-reflection film, a light-shielding film, and a reflection attenuation film are sequentially laminated from the transparent substrate side And anti-reflective film. The photomask is made by patterning each film constituting the photomask base by wet etching or the like to form a specific light-shielding film pattern. [Prior Technical Literature] [Patent Literature]

[專利文獻1]韓國登記專利第10-1473163號公報[Patent Document 1] Korean Registered Patent No. 10-1473163

[發明所欲解決之問題][The problem to be solved by the invention]

因此,於光罩基底中,於藉由蝕刻對遮光膜進行圖案化而製成光罩時,要求其遮光膜圖案之精度高。其原因在於:若遮光膜圖案之精度低,則於使用光罩將遮光膜圖案轉印至被轉印體時,該轉印圖案之線寬或孔圖案之尺寸變得不均,而有損形成於被轉印體之圖案之CD均勻性(CD(Critical Dimension,臨界尺寸) Uniformity)。Therefore, in the photomask substrate, when the photomask is patterned by etching to form the photomask, the precision of the photomask pattern is required to be high. The reason is that if the accuracy of the light-shielding film pattern is low, when the light-shielding film pattern is transferred to the transferred body using the mask, the line width of the transfer pattern or the size of the hole pattern becomes uneven, which is detrimental. CD (Critical Dimension) Uniformity of the pattern formed on the transferred body.

又,亦要求光罩基底之遮光膜正面之反射率較低,從而使得於使用光罩對被轉印體進行曝光處理時可轉印高精度之轉印圖案。若形成於光罩之遮光膜圖案之正面之反射率較高,則存在如下情況:於進行曝光處理時,來自被轉印體之反射光反覆在光罩之遮光膜圖案正面反射,故產生所謂之光斑(flare)。又,例如存在如下情況:來自曝光裝置之曝光之光於光罩之遮光膜圖案之背面反射之反射光再次被曝光裝置(轉印裝置)之光學系統反射,並再次入射至光罩,故產生所謂之回光。存在因該等光斑或回光而有損使用光罩所形成之轉印圖案之圖案精度之情況。In addition, the reflectivity of the front surface of the light-shielding film of the mask substrate is also required to be low, so that the high-precision transfer pattern can be transferred when the mask is used to expose the transferred body. If the reflectivity of the front surface of the light-shielding film pattern formed on the mask is relatively high, there is a situation where the reflected light from the transferred body is reflected on the front side of the light-shielding film pattern of the mask during the exposure process, so the so-called The flare. In addition, for example, there is a situation in which the light from the exposure device is exposed to light reflected on the back surface of the light-shielding film pattern of the photomask. The reflected light is again reflected by the optical system of the exposure device (transfer device) and enters the photomask again. The so-called back to light. There are cases where the pattern accuracy of the transfer pattern formed by using the photomask is impaired due to the light spots or the back light.

因此,本發明之目的在於提供一種具有如下光學特性之光罩基底:藉由蝕刻對光罩基底中之遮光膜進行圖案化而製作光罩時可獲得高精度之遮光膜圖案,且使用光罩將轉印圖案轉印至被轉印體時被轉印體之圖案精度提高。 [解決問題之技術手段]Therefore, the object of the present invention is to provide a photomask substrate with the following optical characteristics: by patterning the light shielding film in the photomask substrate by etching, a high-precision light shielding film pattern can be obtained when the photomask is made, and the photomask is used When the transfer pattern is transferred to the transfer body, the pattern accuracy of the transfer body is improved. [Technical means to solve the problem]

(構成1) 一種光罩基底,其特徵在於 其係製作顯示裝置製造用之光罩時所使用者,且具有: 透明基板,其包含對曝光之光實質上透明之材料;及 遮光膜,其設置於上述透明基板上,且包含對上述曝光之光實質上不透明之材料; 上述遮光膜自上述透明基板側起具備第1反射抑制層、遮光層及第2反射抑制層, 上述第1反射抑制層自上述透明基板側起依序具備:第1低氧化鉻層,其含有鉻、氧及氮,且氧相對於氮之比率相對較少;及第1高氧化鉻層,其含有鉻、氧及氮,且氧相對於氮之比率相對較多; 上述第2反射抑制層自上述透明基板側起依序具備:第2低氧化鉻層,其含有鉻、氧及氮,且氧相對於氮之比率相對較少;及第2高氧化鉻層,其含有鉻、氧及氮,且氧相對於氮之比率相對較多; 以上述遮光膜之正面及背面之對上述曝光之光之曝光波長300 nm~436 nm之反射率分別為15%以下且光學密度成為3.0以上之方式設定至少上述第1反射抑制層、上述遮光層、及上述第2反射抑制層之組成、及膜厚。(Structure 1) A photomask substrate, wherein: the production line which displays the mask when the user of device fabrication, and having: a transparent substrate, comprising the exposure of light of substantially transparent material; and a light shielding film, It is provided on the transparent substrate and includes a material that is substantially opaque to the light exposed to the exposure; the light-shielding film includes a first reflection suppression layer, a light-shielding layer, and a second reflection suppression layer from the transparent substrate side, and the first reflection The suppression layer is provided in order from the transparent substrate side: a first low chromium oxide layer containing chromium, oxygen, and nitrogen, and the ratio of oxygen to nitrogen is relatively small; and a first high chromium oxide layer containing chromium, Oxygen and nitrogen, and the ratio of oxygen to nitrogen is relatively high; the second reflection suppression layer is provided in order from the transparent substrate side: a second low chromium oxide layer containing chromium, oxygen and nitrogen, and oxygen relative to The ratio of nitrogen is relatively small; and the second high chromium oxide layer, which contains chromium, oxygen and nitrogen, and the ratio of oxygen to nitrogen is relatively large; Exposure to the light of the above exposure by the front and back of the light-shielding film The composition and film thickness of at least the first reflection suppression layer, the light shielding layer, and the second reflection suppression layer are set so that the reflectance at a wavelength of 300 nm to 436 nm is 15% or less and the optical density becomes 3.0 or more.

(構成2) 如構成1之光罩基底,其特徵在於:上述遮光層係由鉻之含有率為97原子%以上且100原子%以下之鉻系材料形成。(Composition 2) The mask substrate of composition 1, characterized in that: the light-shielding layer is formed of a chromium-based material with a chromium content of 97 atomic% or more and 100 atomic% or less.

(構成3) 如構成1或2之光罩基底,其特徵在於:上述第2高氧化鉻層中之氧相對於氮之比率為2.5以上且10以下。(Composition 3) For example, the mask substrate of 1 or 2 is characterized in that the ratio of oxygen to nitrogen in the second high chromium oxide layer is 2.5 or more and 10 or less.

(構成4) 如構成1至3中任一項之光罩基底,其特徵在於:上述第1高氧化鉻層中之氧相對於氮之比率為2.5以上且10以下。(Composition 4) Such as constituting any one of 1 to 3 of the mask substrate, characterized in that the ratio of oxygen to nitrogen in the first high chromium oxide layer is 2.5 or more and 10 or less.

(構成5) 如構成1至4中任一項之光罩基底,其特徵在於:上述第1反射抑制層中包含碳。(Composition 5) The mask substrate of any one of components 1 to 4 is characterized in that the first reflection suppression layer contains carbon.

(構成6) 如構成1至5中任一項之光罩基底,其特徵在於:上述第2反射抑制層中包含碳。(Composition 6) The mask substrate of any one of components 1 to 5 is characterized in that the second reflection suppression layer contains carbon.

(構成7) 如構成1至6中任一項之光罩基底,其特徵在於: 上述第1反射抑制層之鉻之含有率為25原子%以上且75原子%以下,氧之含有率為15原子%以上且45原子%以下,氮之含有率為2原子%以上且30原子%以下, 上述第2反射抑制層之鉻之含有率為25原子%以上且75原子%以下,氧之含有率為15原子%以上且60原子%以下,氮之含有率為2原子%以上且30原子%以下。(Composition 7) For example, the mask substrate constituting any one of 1 to 6, characterized by: The chromium content of the above-mentioned first reflection suppression layer is 25 atomic% or more and 75 atomic% or less, the oxygen content is 15 atomic% or more and 45 atomic% or less, and the nitrogen content is 2 atomic% or more and 30 atomic% the following, The chromium content of the second reflection suppression layer is 25 atomic% or more and 75 atomic% or less, the oxygen content is 15 atomic% or more and 60 atomic% or less, and the nitrogen content is 2 atomic% or more and 30 atomic% the following.

(構成8) 如構成1至7中任一項之光罩基底,其特徵在於:上述第1反射抑制層及上述第2反射抑制層分別具有氧及氮中之至少任一元素之含有率沿著膜厚方向連續地或者階段性地組成變化之區域。(Composition 8) The mask substrate of any one of 1 to 7, characterized in that: the first reflection suppression layer and the second reflection suppression layer each have at least one of oxygen and nitrogen. The content of at least any element is along the film thickness direction. Consecutively or step by step constitute the area of change.

(構成9) 如構成1至8中任一項之光罩基底,其特徵在於:其於上述透明基板與上述第1反射抑制層之間、上述第1反射抑制層與上述遮光層之間、及上述遮光層與上述第2反射抑制層之間具有構成上述第1反射抑制層、上述遮光層及上述第2反射抑制層之元素連續地組成梯度變化之梯度組成區域。(Composition 9) The mask base of any one of 1 to 8, characterized in that it is located between the transparent substrate and the first reflection suppression layer, between the first reflection suppression layer and the light-shielding layer, and the light-shielding layer Between the second reflection suppression layer and the second reflection suppression layer, there is a gradient composition region in which the elements constituting the first reflection suppression layer, the light shielding layer, and the second reflection suppression layer continuously form a gradient change.

(構成10) 如構成1至9中任一項之光罩基底,其特徵在於:上述遮光膜之正面對上述曝光之光之曝光波長之反射率之面內均勻性為3%以下。(Composition 10) For example, the mask substrate of any one of 1 to 9 is characterized in that the in-plane uniformity of the reflectance of the front surface of the light-shielding film to the exposure wavelength of the exposure light is 3% or less.

(構成11) 如構成1至10中任一項之光罩基底,其特徵在於:其於上述透明基板與上述遮光膜之間進而具備半透光膜,該半透光膜具有較上述遮光膜之光學密度低之光學密度。(Composition 11) For example, the mask base of any one of 1 to 10 is characterized in that it is further provided with a semi-transmissive film between the transparent substrate and the light-shielding film, and the semi-light-transmitting film has a lower optical density than the light-shielding film. The optical density.

(構成12) 如構成1至10中任一項之光罩基底,其特徵在於:其於上述透明基板與上述遮光膜之間進而具備相位偏移膜。(Composition 12) The mask base of any one of compositions 1 to 10 is characterized in that it further includes a phase shift film between the transparent substrate and the light-shielding film.

(構成13) 一種光罩之製造方法,其特徵在於具有如下步驟: 準備如構成1至12中任一項之上述光罩基底;及 於上述遮光膜上形成抗蝕膜,將由上述抗蝕膜形成之抗蝕圖案作為遮罩對上述遮光膜進行蝕刻而於上述透明基板上形成遮光膜圖案之步驟。(Composition 13) A method for manufacturing a photomask is characterized by the following steps: Prepare the above-mentioned mask substrate as constituting any one of 1 to 12; and A step of forming a resist film on the light-shielding film, and etching the light-shielding film using the resist pattern formed of the resist film as a mask to form a light-shielding film pattern on the transparent substrate.

(構成14) 一種光罩之製造方法,其特徵在於具有如下步驟: 準備如構成1至12中任一項之上述光罩基底; 於上述遮光膜上形成抗蝕膜,將由上述抗蝕膜形成之抗蝕圖案作為遮罩對上述遮光膜進行蝕刻而於上述透明基板上形成遮光膜圖案;及 將上述遮光膜圖案作為遮罩對上述半透光膜進行蝕刻而於上述透明基板上形成半透光膜圖案。(Composition 14) A method for manufacturing a photomask is characterized by the following steps: Prepare the above-mentioned mask substrate as any one of 1 to 12; Forming a resist film on the light-shielding film, etching the light-shielding film using the resist pattern formed by the resist film as a mask to form a light-shielding film pattern on the transparent substrate; and The translucent film is etched using the light-shielding film pattern as a mask to form a translucent film pattern on the transparent substrate.

(構成15) 一種光罩之製造方法,其特徵在於具有如下步驟: 準備如構成1至12中任一項之上述光罩基底; 於上述遮光膜上形成抗蝕膜,將由上述抗蝕膜形成之抗蝕圖案作為遮罩對上述遮光膜進行蝕刻而於上述透明基板上形成遮光膜圖案;及 將上述遮光膜圖案作為遮罩對上述相位偏移膜進行蝕刻而於上述透明基板上形成相位偏移膜圖案。(Composition 15) A method for manufacturing a photomask, which is characterized in that it has the following steps: Prepare the above-mentioned mask substrate as any one of 1 to 12; Forming a resist film on the light-shielding film, etching the light-shielding film using the resist pattern formed by the resist film as a mask to form a light-shielding film pattern on the transparent substrate; and The phase shift film is etched using the light-shielding film pattern as a mask to form a phase shift film pattern on the transparent substrate.

(構成16) 一種顯示裝置之製造方法,其特徵在於具有:曝光步驟,其將藉由如構成13至15中任一項之光罩之製造方法而獲得之光罩載置於曝光裝置之遮罩台,並將形成於上述光罩上之遮光膜圖案、上述半透光膜圖案、上述相位偏移膜圖案之至少一個遮光膜圖案曝光轉印至形成於顯示裝置基板上之抗蝕劑。 [發明之效果](Composition 16) A method of manufacturing a display device, characterized by having: an exposure step, which places the photomask obtained by the manufacturing method of the photomask as configured in any one of 13 to 15 on the mask stage of the exposure device, and At least one of the light-shielding film pattern, the semi-transmissive film pattern, and the phase shift film pattern formed on the photomask is exposed and transferred to the resist formed on the substrate of the display device. [Effects of the invention]

根據本發明,可獲得能夠製造具有如下光學特性之光罩之光罩基底:藉由蝕刻對光罩基底中之遮光膜進行圖案化而製作光罩時可獲得高精度之遮光膜圖案,且於使用光罩將轉印圖案轉印至被轉印體時被轉印體之圖案精度提高。According to the present invention, it is possible to obtain a mask substrate capable of manufacturing a mask with the following optical characteristics: patterning the light-shielding film in the mask substrate by etching to obtain a high-precision light-shielding film pattern when making the mask, and When using a photomask to transfer the transfer pattern to the transfer body, the pattern accuracy of the transfer body is improved.

<本發明者等人之研究> 關於遮光膜自透明基板側起依序積層第1反射抑制層、遮光層及第2反射抑制層而構成之光罩基底,為了改善該光罩基底之光學特性,本發明者等人進行了研究。然而,確認到僅憑使光罩基底中之遮光膜之正面及背面之反射率降低,轉印至被轉印體之轉印圖案之精度不會提高。<Research by the inventors and others> Regarding a mask base formed by laminating a first reflection suppressing layer, a light shielding layer, and a second reflection suppressing layer in order from the transparent substrate side of the light-shielding film, in order to improve the optical characteristics of the mask base, the inventors conducted research . However, it was confirmed that only by reducing the reflectivity of the front and back of the light-shielding film in the mask base, the accuracy of the transfer pattern transferred to the transferred body would not be improved.

針對其主要原因進行了研究,結果發現,被轉印體之轉印圖案精度降低之主要原因在於,光罩基底之遮光膜之正面及背面之反射率於面內不均勻(反射率之面內不均較大)。於遮光膜中,第1及第2反射抑制層為了降低反射率而進行氧化,但有其氧化程度於面內不均之傾向。又,於使遮光層氮化之情形時,有其氮化程度亦於面內不均之傾向。因第1及第2反射抑制層之氧化程度或遮光層之氮化程度於面內不均而導致遮光膜之正面及背面之反射率於面內變得不均勻。The main reason for this has been studied, and it was found that the main reason for the decrease in the accuracy of the transfer pattern of the transferred body is that the reflectivity of the front and back of the light-shielding film of the mask substrate is not uniform in the plane (the reflectivity in the plane) Larger unevenness). In the light-shielding film, the first and second reflection suppression layers are oxidized in order to reduce the reflectivity, but the degree of oxidation tends to be uneven in the plane. In addition, when nitriding the light-shielding layer, the degree of nitriding tends to be uneven in the plane. Because the degree of oxidation of the first and second reflection suppression layers or the degree of nitridation of the light-shielding layer is uneven in the plane, the reflectivity of the front and back sides of the light-shielding film becomes uneven in the plane.

又,為了使遮光膜之正面及背面之反射率更低,第1反射抑制層或第2反射抑制層需被更強地氧化,但成膜時容易產生缺陷。In addition, in order to lower the reflectance of the front and back surfaces of the light-shielding film, the first reflection suppression layer or the second reflection suppression layer must be more strongly oxidized, but defects are likely to occur during film formation.

光罩中,因遮光膜圖案之正面及背面之反射率於面內變得不均勻(反射率之面內不均增大)而無法將光罩之遮光膜圖案精確地轉印至被轉印體,有損所獲得之被轉印體之轉印圖案之CD均勻性。In the mask, because the reflectivity of the front and back of the light-shielding film pattern becomes uneven in the plane (the unevenness of the reflectance increases), it is impossible to accurately transfer the light-shielding film pattern of the mask to the transfer. The CD uniformity of the transfer pattern of the transferred body is impaired.

另一方面,對光罩基底之遮光膜進行蝕刻時所獲得之遮光膜圖案之圖案精度降低之主要原因在於,構成遮光膜之各層之蝕刻速率或蝕刻時間不一致。若構成遮光膜之各層之蝕刻速率或蝕刻時間有巨大差距,則於對遮光膜進行蝕刻而形成遮光膜圖案時,尤其容易於第1反射抑制層之透明基板側之部位產生蝕刻殘留。若產生蝕刻殘留,則遮光膜圖案之剖面形狀不易呈垂直,因此遮光膜圖案之線寬於正面側及背面側變得不同,而導致光罩之遮光膜圖案之精度降低。On the other hand, the main reason for the decrease in the pattern accuracy of the light-shielding film pattern obtained when the light-shielding film of the mask substrate is etched is that the etching rate or etching time of each layer constituting the light-shielding film is inconsistent. If there is a huge difference in the etching rate or etching time of each layer constituting the light-shielding film, when the light-shielding film is etched to form the light-shielding film pattern, etching residues are particularly likely to occur at the transparent substrate side of the first reflection suppression layer. If etching residue occurs, the cross-sectional shape of the light-shielding film pattern is not easy to be vertical, so the line width of the light-shielding film pattern becomes different on the front side and the back side, resulting in a decrease in the accuracy of the light-shielding film pattern of the mask.

根據以上情況,本發明者等人對使光罩基底中之遮光膜之正面及背面之反射率於面內均勻之方法進行了研究。此前之光罩基底中之第1反射抑制層及第2反射抑制層一般分別係由高氧化層之單層構成。然而,認為於以高氧化層之單層構成第1反射抑制層及第2反射抑制層 情形時,於光罩基底面內,第1反射抑制層及第2反射抑制層之氧化程度之不均變得更顯著,會對遮光膜之正面及背面之反射率之面內不均造成較大之影響。又,認為因使第1反射抑制層及第2反射抑制層之氧化程度較高,而容易產生缺陷。Based on the above situation, the inventors of the present invention conducted research on a method for making the reflectance of the front and back of the light-shielding film in the mask substrate uniform in the plane. The first reflection suppression layer and the second reflection suppression layer in the previous photomask substrate are generally composed of a single layer of a high-oxidation layer. However, in a single layer that constitutes the high oxide case of first reflection suppressing layer and a second reflection suppressing layer, the surface of the substrate in the mask, the degree of reflection suppression of the second oxide layer of the first reflective layer does not inhibit the Both become more significant, which will have a greater impact on the in-plane unevenness of the reflectivity of the front and back of the shading film. In addition, it is considered that the first reflection suppression layer and the second reflection suppression layer are oxidized to a high degree, and defects are likely to occur.

因此,本發明者等人著眼於以低氧化層與高氧化層之氧化程度不同之2層積層構造構成第1及第2反射抑制層,進行了研究。結果發現,與僅以高氧化層之單層構成第1及第2反射抑制層之情形相比,可使遮光膜之正面及背面之反射率於光罩基底面內更均勻、或可減少遮光膜之缺陷。並且發現,藉由自透明基板側起依序以低氧化層與高氧化層構成第1反射抑制層,第1反射抑制層之透明基板側之部位之蝕刻殘留得到抑制,結果可使遮光膜圖案之剖面形狀良好,而獲得高精度之遮光膜圖案。Therefore, the inventors of the present invention focused on constructing the first and second reflection suppression layers with a two-layered structure in which the degree of oxidation of the low-oxidation layer and the high-oxidation layer were different, and studied. As a result, it was found that, compared with the case where the first and second reflection suppression layers are composed of only a single layer of a high-oxidation layer, the reflectivity of the front and back of the light-shielding film can be made more uniform in the base surface of the mask, or the light-shielding can be reduced Defects of the membrane. It was also found that by constructing the first reflection suppression layer with a low-oxidation layer and a high-oxidation layer in order from the transparent substrate side, the etching residue on the transparent substrate side of the first reflection suppression layer was suppressed. As a result, the light-shielding film pattern could be achieved. The cross-sectional shape is good, and a high-precision shading film pattern is obtained.

又,發現就使遮光膜之正面及背面之反射率於光罩基底面內更均勻之觀點而言,較佳為儘可能地將遮光膜中之遮光層設為接近不會氧化或氮化之金屬膜之狀態。迄今為止,就控制遮光膜之蝕刻速率(蝕刻時間)之觀點而言,遮光層係由包含氮之金屬膜(金屬氮化膜)構成。然而,若使遮光層中含有氮,則會於光罩基底面內產生含氮率之不均(不均勻性)。又,由於位於遮光層之上下之第1及第2反射抑制層中含有氧,故而第1及第2反射抑制層亦會於光罩基底面內產生含氧率之不均(不均勻性)。該遮光層中之含氮率於光罩基底面內之不均(不均勻性)與第1及第2反射抑制層中之含氧率於光罩基底面內之不均相輔相成而導致遮光膜之正面及背面之反射率之面內不均(不均勻性)增大。為了減小遮光膜之正面及背面之反射率之面內不均,減小遮光層中所包含之光罩基底面內之氮之不均更有效果,因此,可藉由減小遮光層中所包含之氮之含有率(不添加氮)來減小遮光膜之正面及背面之反射率之面內不均。In addition, it has been found that from the viewpoint of making the reflectance of the front and back surfaces of the light-shielding film more uniform in the surface of the mask base, it is better to set the light-shielding layer in the light-shielding film as close as possible to one that does not oxidize or nitride. The state of the metal film. So far, from the viewpoint of controlling the etching rate (etching time) of the light-shielding film, the light-shielding layer is composed of a metal film (metal nitride film) containing nitrogen. However, if nitrogen is contained in the light-shielding layer, a non-uniformity (non-uniformity) of nitrogen content will occur in the base surface of the photomask. In addition, since the first and second reflection suppression layers located above and below the light-shielding layer contain oxygen, the first and second reflection suppression layers will also produce uneven oxygen content (unevenness) in the base surface of the mask. . The unevenness (unevenness) of the nitrogen content of the light-shielding layer in the surface of the mask substrate and the unevenness of the oxygen content of the first and second reflection suppression layers in the surface of the mask substrate are complementary to each other, resulting in the light-shielding film The in-plane unevenness (unevenness) of the reflectance of the front and back sides increases. In order to reduce the in-plane unevenness of the reflectivity of the front and back of the light-shielding film, it is more effective to reduce the nitrogen unevenness in the base surface of the mask contained in the light-shielding layer. Therefore, it is possible to reduce the unevenness in the light-shielding layer The contained nitrogen content rate (no nitrogen added) reduces the in-plane unevenness of the reflectance of the front and back surfaces of the light-shielding film.

本發明係基於上述見解而成者。The present invention is based on the above findings.

<本發明之一實施方式> 以下,對本發明之一實施方式進行說明。再者,以下實施方式係使本發明具體化時之一方式,並不將本發明限定於該範圍內。又,圖中,有時會對相同或相當之部分標註相同符號並簡化或省略其說明。又,於本說明書中,使用「~」表示之數值範圍意指包含「~」之前後所記載之數值作為下限值及上限值之範圍。<One embodiment of the present invention> Hereinafter, an embodiment of the present invention will be described. In addition, the following embodiment is an aspect when the present invention is embodied, and the present invention is not limited to this scope. In addition, in the drawings, the same or equivalent parts may be denoted with the same reference numerals and their descriptions may be simplified or omitted. In addition, in this specification, the numerical range indicated by "~" means the range that includes the numerical values described before and after "~" as the lower limit and the upper limit.

(1)光罩基底 首先,對本發明之一實施方式之光罩基底進行說明。本實施方式之光罩基底係於製造對例如選自300 nm~436 nm之波長頻帶之單波長之光或包含複數個波長之光(例如j線(波長313 nm)、波長334 nm、i線(波長365 nm)、h線(405 nm)、g線(波長436 nm))之複合光進行曝光之顯示裝置製造用之光罩時所使用者。(1) Mask base First, the photomask substrate of one embodiment of the present invention will be described. The photomask substrate of this embodiment is used for manufacturing light of a single wavelength selected from the wavelength band of 300 nm to 436 nm or light containing multiple wavelengths (for example, j-line (wavelength 313 nm), wavelength 334 nm, i-line (Wavelength 365 nm), h-line (405 nm), g-line (wavelength 436 nm)) composite light exposure for display device manufacturing masks.

圖1係表示本發明之一實施方式之光罩基底之概略構成的剖視圖。光罩基底1具備透明基板11及遮光膜12而構成。以下,作為本發明之一實施方式之光罩基底,對光罩之遮光膜圖案(轉印圖案)為遮光膜圖案之二元式光罩基底進行說明。FIG. 1 is a cross-sectional view showing a schematic configuration of a photomask substrate according to an embodiment of the present invention. The mask base 1 includes a transparent substrate 11 and a light-shielding film 12. Hereinafter, as a mask base of one embodiment of the present invention, a binary mask base in which the light-shielding film pattern (transfer pattern) of the light-shielding film is a light-shielding film pattern will be described.

(透明基板) 透明基板11係由對曝光之光實質上透明之材料形成,只要為具有透光性之基板,則並無特別限定。使用對曝光波長之透過率為85%以上、較佳為90%以上之基板材料。作為形成透明基板11之材料,例如可例舉:合成石英玻璃、鈉鈣玻璃、無鹼玻璃、低熱膨脹玻璃。(Transparent substrate) The transparent substrate 11 is formed of a material that is substantially transparent to exposure light, and is not particularly limited as long as it is a transparent substrate. Use a substrate material whose transmittance to the exposure wavelength is 85% or more, preferably 90% or more. Examples of the material forming the transparent substrate 11 include synthetic quartz glass, soda lime glass, alkali-free glass, and low thermal expansion glass.

透明基板11之大小並無特別限定,可對應於光罩所要求之大小適當變更。例如,若為顯示裝置製造用之光罩之情形,則可使用矩形狀之基板並且其短邊之長度為330 mm以上且1620 mm以下之大小之透明基板11作為透明基板11。作為透明基板11,例如可使用大小為330 mm×450 mm、390 mm×610 mm、500 mm×750 mm、520 mm×610 mm、520 mm×800 mm、800×920 mm、850 mm×1200 mm、850 mm×1400 mm、1220 mm×1400 mm、1620 mm×1780 mm等之基板。尤佳為基板之短邊之長度為850 mm以上且1620 mm以下。藉由使用此種透明基板11,可獲得G7~G10之顯示裝置製造用之光罩。The size of the transparent substrate 11 is not particularly limited, and can be appropriately changed according to the required size of the photomask. For example, in the case of a photomask for manufacturing a display device, a rectangular substrate and a transparent substrate 11 with a short side length of 330 mm or more and 1620 mm or less can be used as the transparent substrate 11. As the transparent substrate 11, for example, sizes of 330 mm × 450 mm, 390 mm × 610 mm, 500 mm × 750 mm, 520 mm × 610 mm, 520 mm × 800 mm, 800 × 920 mm, 850 mm × 1200 mm can be used. , 850 mm×1400 mm, 1220 mm×1400 mm, 1620 mm×1780 mm, etc. It is particularly preferable that the length of the short side of the substrate is 850 mm or more and 1620 mm or less. By using such a transparent substrate 11, a photomask for manufacturing display devices of G7 to G10 can be obtained.

(遮光膜) 遮光膜12係由對曝光之光實質上不透明之材料形成,自透明基板11側起依序積層有第1反射抑制層13、遮光層14及第2反射抑制層15而構成。再者,於本說明書中,將光罩基底1之兩面中遮光膜12側之面設為正面,將透明基板11側之面設為背面。 並且,以遮光膜12之正面及背面對上述曝光之光之曝光波長300 nm~436 nm之反射率分別為15%以下且光學密度成為3.0以上之方式設定至少第1反射抑制層13、遮光層14及第2反射抑制層15之組成、及膜厚。又,亦可以對於來自遮光膜12之背面側之曝光之光之代表波長365 nm~436 nm成為10%以下之方式調整至少第1反射抑制層13中之第1低氧化鉻層13a、及第1高氧化鉻層13b之組成比、膜厚。(Shading film) The light-shielding film 12 is formed of a material that is substantially opaque to exposure light. The first reflection-inhibiting layer 13, the light-shielding layer 14, and the second reflection-inhibiting layer 15 are sequentially laminated from the transparent substrate 11 side. In addition, in this specification, the surface on the light-shielding film 12 side among the two surfaces of the mask base 1 is referred to as the front surface, and the surface on the transparent substrate 11 side is referred to as the back surface. In addition, at least the first reflection suppression layer 13 and the light-shielding layer are set so that the reflectance of the front and back surfaces of the light shielding film 12 to the exposure wavelength of the above-mentioned exposure light is 15% or less and the optical density becomes 3.0 or more. 14 and the composition and film thickness of the second reflection suppression layer 15. In addition, it is also possible to adjust at least the first low chromium oxide layer 13a in the first reflection suppression layer 13 and the first low chromium oxide layer 13a in the first reflection suppression layer 13 and the first low chromium oxide layer 13a and the second 1 Composition ratio and film thickness of the high chromium oxide layer 13b.

(第1反射抑制層) 第1反射抑制層13於遮光膜12中設置於遮光層14之靠近透明基板11側之面,且配置與於利用使用光罩基底1而製作之光罩進行圖案轉印之情形時靠近曝光裝置(曝光之光源)側。於使用光罩進行曝光處理之情形時,自光罩之透明基板11側(背面側)照射曝光之光,將圖案轉印像轉印至形成於作為被轉印體之顯示裝置用基板上之抗蝕膜。此時,曝光之光於遮光膜圖案之背面側反射後之反射光入射至曝光裝置之光學系統,並再次自光罩之透明基板11側入射,因此成為遮光膜圖案之雜散光,而成為形成重像或光斑量增加等轉印圖案之劣化要因。於使用光罩進行圖案轉印時,可藉由第1反射抑制層13抑制曝光之光於遮光膜12之背面側之反射,因此可抑制轉印圖案之劣化而提高轉印特性。(The first reflection suppression layer) The first reflection suppression layer 13 is provided in the light-shielding film 12 on the side of the light-shielding layer 14 near the transparent substrate 11, and is arranged close to the exposure device when pattern transfer is performed using a photomask made using the photomask base 1 (Light source of exposure) side. In the case of exposure processing using a photomask, the exposure light is irradiated from the transparent substrate 11 side (rear side) of the photomask to transfer the pattern transfer image to the substrate formed on the display device as the transferred body Resist film. At this time, the reflected light after the exposure light is reflected on the back side of the light-shielding film pattern enters the optical system of the exposure device, and then enters from the transparent substrate 11 side of the mask again, so it becomes the stray light of the light-shielding film pattern and becomes the formation Deterioration of the transferred pattern such as ghosting or increased amount of flare. When a photomask is used for pattern transfer, the first reflection suppressing layer 13 can suppress the reflection of exposed light on the back side of the light shielding film 12, thereby suppressing the deterioration of the transferred pattern and improving the transfer characteristics.

如上所述,於本實施方式中,為了能夠減少缺陷,又,為了降低遮光膜12之背面之反射率且提高光罩基底面內之反射率之均勻性(為了抑制反射率之面內不均),第1反射抑制層13係自透明基板11側起依序積層氧化相對較少之第1低氧化鉻層13a與氧化相對較多之第1高氧化鉻層13b而構成。As described above, in this embodiment, in order to reduce defects, and to reduce the reflectivity of the back surface of the light-shielding film 12, and to improve the uniformity of the reflectance in the surface of the mask base (in order to suppress the in-plane unevenness of the reflectance) ), the first reflection suppression layer 13 is formed by sequentially stacking a first low-chromium oxide layer 13a with relatively little oxidation and a first high-chromium oxide layer 13b with relatively high oxidation from the transparent substrate 11 side.

第1低氧化鉻層13a係以氧化度減小之方式形成。The first low chromium oxide layer 13a is formed in such a way that the degree of oxidation is reduced.

又,第1低氧化鉻層13a如下所述,與第1高氧化鉻層13b相比,氧(O)相對於氮(N)之比率較小、即N之含有率增多,故而相較於第1高氧化鉻層13b能夠縮短蝕刻時間。因此,於對光罩基底1進行蝕刻時,可防止第1低氧化鉻層13a之蝕刻殘留,又,可使遮光膜圖案之剖面形狀更接近垂直。In addition, the first low chromium oxide layer 13a is as follows. Compared with the first high chromium oxide layer 13b, the ratio of oxygen (O) to nitrogen (N) is small, that is, the N content is increased, so it is compared with The first high chromium oxide layer 13b can shorten the etching time. Therefore, when the photomask base 1 is etched, the etching residue of the first low chromium oxide layer 13a can be prevented, and the cross-sectional shape of the light-shielding film pattern can be made closer to vertical.

又,第1低氧化鉻層13a由於氧化度變小、N之含量增多,故而即便於對遮光膜12進行蝕刻而形成有微細之遮光膜圖案之情形時,亦可確保與透明基板11之密接性而防止遮光膜圖案之膜剝落。In addition, since the degree of oxidation of the first low chromium oxide layer 13a decreases and the content of N increases, even when the light-shielding film 12 is etched to form a fine light-shielding film pattern, it is possible to ensure close contact with the transparent substrate 11 It can prevent the peeling of the film of the shading film pattern.

第1高氧化鉻層13b提高氧化度而使遮光膜12之背面反射率(第1反射抑制層13之背面反射率)成為特定之特性。The first high chromium oxide layer 13b increases the degree of oxidation so that the back surface reflectance of the light shielding film 12 (the back surface reflectance of the first reflection suppression layer 13) becomes a specific characteristic.

(遮光層) 遮光層14於遮光膜12中設置於第1反射抑制層13與第2反射抑制層15之間。遮光層14具有如下功能,即,以具有用以使遮光膜12對曝光之光實質上不透明之光學密度之方式進行調整。此處,所謂對曝光之光實質上不透明,係指以光學密度計為3.0以上之遮光性,就轉印特性之觀點而言,較佳為光學密度為4.0以上,進而較佳為4.5以上。(Shading layer) The light-shielding layer 14 is provided in the light-shielding film 12 between the first reflection suppression layer 13 and the second reflection suppression layer 15. The light-shielding layer 14 has a function of being adjusted so as to have an optical density for making the light-shielding film 12 substantially opaque to exposed light. Here, the term "substantially opaque to exposure light" means a light-shielding property of 3.0 or more in terms of optical density. From the viewpoint of transfer characteristics, the optical density is preferably 4.0 or more, and more preferably 4.5 or more.

(第2反射抑制層) 第2反射抑制層15於遮光膜12中設置於遮光層14之遠離透明基板11側之面。第2反射抑制層15具有如下功能:於其上形成抗蝕膜並藉由描繪裝置(例如雷射描繪裝置)之描繪光(雷射光)於該抗蝕膜形成特定之抗蝕圖案時,抑制上述描繪光於遮光膜12之正面側反射。藉此,可提高抗蝕圖案、以及由其形成之遮光膜圖案之CD均勻性。另一方面,第2反射抑制層15於使用光罩時配置於被轉印體側,抑制經被轉印體反射之光於光罩之遮光膜12之正面側再次反射後返回到被轉印體。藉此,抑制轉印圖案之劣化而有助於提高轉印特性。(Second reflection suppression layer) The second reflection suppression layer 15 is provided in the light-shielding film 12 on the surface of the light-shielding layer 14 away from the transparent substrate 11. The second reflection suppression layer 15 has a function of forming a resist film thereon and suppressing the formation of a specific resist pattern by drawing light (laser light) from a drawing device (for example, a laser drawing device) on the resist film. The above-mentioned drawing light is reflected on the front side of the light-shielding film 12. Thereby, the CD uniformity of the resist pattern and the light-shielding film pattern formed therefrom can be improved. On the other hand, the second reflection suppression layer 15 is arranged on the side of the transfer object when the photomask is used, and suppresses the light reflected by the transfer object from being reflected again on the front side of the light shielding film 12 of the photomask and then returning to the transfer object. body. This suppresses the deterioration of the transfer pattern and contributes to the improvement of transfer characteristics.

第2反射抑制層15與第1反射抑制層13同樣地,係由氧化度不同之2層氧化鉻層構成。具體而言,為了能夠減少缺陷,又,為了降低遮光膜12之正面反射率且提高光罩基底面內之正面反射率之均勻性(為了抑制正面反射率之面內不均),第2反射抑制層15係自遮光層14側起依序積層氧化相對較少之第2低氧化鉻層15a與氧化相對較多之第2高氧化鉻層15b而構成。The second reflection suppression layer 15 is, like the first reflection suppression layer 13, composed of two chromium oxide layers with different oxidation degrees. Specifically, in order to reduce defects, and to reduce the front reflectance of the light shielding film 12 and improve the uniformity of the front reflectance in the mask base surface (in order to suppress the in-plane unevenness of the front reflectance), the second reflection The suppression layer 15 is formed by sequentially stacking a second low-chromium oxide layer 15a with relatively little oxidation and a second high-chromium oxide layer 15b with relatively high oxidation from the light-shielding layer 14 side.

第2低氧化鉻層15a與第1低氧化鉻層13a相同,係以氧化度減小之方式形成。The second low chromium oxide layer 15a is the same as the first low chromium oxide layer 13a, and is formed in such a way that the degree of oxidation is reduced.

第2高氧化鉻層15b提高了氧化度而使遮光膜12之正面反射率(第2反射抑制層15之正面之反射率)成為特定之特性。又,第2高氧化鉻層15b藉由使氧化度較高,亦有助於提高對於將光罩基底或光罩洗淨時所使用之酸或鹼等洗淨液之耐化學品性或於第2高氧化鉻層15b上形成有抗蝕膜時之與抗蝕膜之較高之密接性。The second high chromium oxide layer 15b increases the degree of oxidation, so that the front surface reflectance of the light shielding film 12 (the front surface reflectance of the second reflection suppression layer 15) becomes a specific characteristic. In addition, the second high chromium oxide layer 15b has a higher degree of oxidation, which also contributes to improving the chemical resistance or resistance to cleaning solutions such as acid or alkali used when cleaning the photomask substrate or the photomask. When a resist film is formed on the second high chromium oxide layer 15b, the adhesion to the resist film is relatively high.

(遮光膜之材料) 繼而,對遮光膜12中之第1反射抑制層13、遮光層14、第2反射抑制層之各層之形成材料進行說明。(Material of shading film) Next, the formation materials of each layer of the first reflection suppression layer 13, the light shielding layer 14, and the second reflection suppression layer in the light shielding film 12 will be described.

第1反射抑制層13、遮光層14、第2反射抑制層之各層之材料只要為可於光罩基底1中獲得上述光學特性者,則並無特別限定,就獲得上述光學特性之觀點而言,各層較佳為使用以下材料。The material of each layer of the first reflection suppression layer 13, the light shielding layer 14, and the second reflection suppression layer is not particularly limited as long as the above-mentioned optical characteristics can be obtained in the photomask base 1. From the viewpoint of obtaining the above-mentioned optical characteristics For each layer, the following materials are preferably used.

第1反射抑制層13較佳為由含有鉻、氧及氮之鉻系材料構成。氧(O)主要具有使第1反射抑制層13之反射率降低之功能。氮(N)主要具有使第1反射抑制層13之反射率降低並且提高第1反射抑制層13之蝕刻速率而縮短蝕刻時間之功能。再者,就控制蝕刻特性之觀點而言,亦可使第1反射抑制層13中進而含有碳(C)或氟(F),尤佳為含有碳(C)。藉由使第1反射抑制層13中含有C,容易使第1反射抑制層13與遮光層14之蝕刻速率一致,從而可使遮光膜圖案之剖面形狀更良好。The first reflection suppression layer 13 is preferably made of a chromium-based material containing chromium, oxygen, and nitrogen. Oxygen (O) mainly has a function of reducing the reflectance of the first reflection suppression layer 13. Nitrogen (N) mainly has the function of reducing the reflectance of the first reflection suppressing layer 13 and increasing the etching rate of the first reflection suppressing layer 13 to shorten the etching time. Furthermore, from the viewpoint of controlling the etching characteristics, the first reflection suppression layer 13 may further contain carbon (C) or fluorine (F), and it is particularly preferable to contain carbon (C). By including C in the first reflection suppression layer 13, the etching rates of the first reflection suppression layer 13 and the light-shielding layer 14 can be easily matched, and the cross-sectional shape of the light-shielding film pattern can be made better.

第1反射抑制層13係由氧化度不同之第1低氧化鉻層13a及第1高氧化鉻層13b構成。所謂氧化度,表示氧相對於氮之比率(以下,亦稱為O/N比),第1低氧化鉻層13a係由O相對於N之比率相對較小之鉻系材料形成,第1高氧化鉻層13b係由O相對於N之比率相對較大之鉻系材料形成。The first reflection suppression layer 13 is composed of a first low-chromium oxide layer 13a and a first high-chromium oxide layer 13b with different oxidation degrees. The degree of oxidation refers to the ratio of oxygen to nitrogen (hereinafter, also referred to as O/N ratio). The first low chromium oxide layer 13a is formed of a chromium-based material with a relatively small ratio of O to N, and the first high The chromium oxide layer 13b is formed of a chromium-based material with a relatively large ratio of O to N.

遮光層14係由鉻系材料構成。遮光層14中,除鉻(Cr)以外,亦可包含O、N、C、F等。就使遮光膜12之正面反射率及背面反射率於光罩基底面內更均勻之觀點而言,較佳為設為遮光層14中實質上不包含O、N、F之鉻膜。所謂實質上不包含O、N、F,表示不會刻意添加,不可避免地包含之情形除外。更具體而言,所謂實質上不包含O、N、F之鉻膜,係指該等元素之合計含有率為3原子%以下、進而該等元素之合計含有率為2原子%以下之鉻膜。如上所述,於遮光層14中無法使含氮率於面內均勻,且會使與第1反射抑制層13及第2反射抑制層15之間之折射率差過大或過小,因此存在會助長光罩基底1中之背面反射率或正面反射率之面內不均之情況。關於該情況,可藉由製成遮光層14實質上不包含O、N、F之鉻膜而使遮光膜12之正面反射率及背面反射率於光罩基底面內更均勻。The light shielding layer 14 is made of a chromium-based material. The light shielding layer 14 may contain O, N, C, F, etc. in addition to chromium (Cr). From the viewpoint of making the front reflectance and back reflectance of the light-shielding film 12 more uniform in the surface of the mask base, it is preferable to set the light-shielding layer 14 as a chromium film that does not substantially contain O, N, and F. The fact that O, N, and F are not substantially included means that they will not be added deliberately, except in cases where they are unavoidably included. More specifically, the so-called chromium film that does not substantially contain O, N, and F refers to a chromium film in which the total content of these elements is 3 atomic% or less, and the total content of these elements is 2 atomic% or less . As described above, the nitrogen content in the light shielding layer 14 cannot be made uniform in the plane, and the refractive index difference with the first reflection suppression layer 13 and the second reflection suppression layer 15 will be too large or too small, so the presence of The in-plane unevenness of the back reflectance or the front reflectance in the mask substrate 1. In this case, the front reflectance and the back reflectance of the light shielding film 12 can be made more uniform in the surface of the mask base by forming a chromium film that does not substantially contain O, N, and F in the light shielding layer 14.

第2反射抑制層15較佳為由含有鉻、氧及氮之鉻系材料構成。於第2反射抑制層15中,氧(O)具有如下功能:不僅降低曝光之光或描繪光之反射率,亦提高與抗蝕膜之密接性,從而抑制因蝕刻劑自抗蝕膜與遮光膜12之界面滲透而導致之側蝕。氮(N)降低第2反射抑制層15之反射率,並且提高第2反射抑制層15之蝕刻速率而縮短蝕刻時間。再者,就控制蝕刻特性之觀點而言,亦可進而含有碳(C)或氟(F),尤佳為含有碳(C)。藉由使第2反射抑制層15含有C,容易使第2反射抑制層15與遮光層14之蝕刻速率一致,從而可使遮光膜圖案之剖面形狀更良好。The second reflection suppression layer 15 is preferably made of a chromium-based material containing chromium, oxygen, and nitrogen. In the second reflection suppression layer 15, oxygen (O) has the following function: not only reduces the reflectance of exposure light or drawing light, but also improves the adhesion to the resist film, thereby suppressing the resist film and light shielding due to the etchant. The interfacial penetration of the membrane 12 causes undercutting. Nitrogen (N) reduces the reflectivity of the second reflection suppression layer 15 and increases the etching rate of the second reflection suppression layer 15 to shorten the etching time. Furthermore, from the viewpoint of controlling etching characteristics, carbon (C) or fluorine (F) may be further contained, and carbon (C) is particularly preferably contained. By making the second reflection suppression layer 15 contain C, it is easy to make the etching rates of the second reflection suppression layer 15 and the light shielding layer 14 equal, and the cross-sectional shape of the light shielding film pattern can be made better.

(遮光膜之組成) 繼而,對遮光膜12中之各層之組成具體地進行說明。再者,下述各元素之含有率設為藉由X射線光電分光法(XPS)所測得之值。(Composition of shading film) Next, the composition of each layer in the light-shielding film 12 will be described in detail. In addition, the content rate of each of the following elements is the value measured by X-ray photoelectric spectroscopy (XPS).

形成第1低氧化鉻層13a之鉻系材料較佳為包含鉻(Cr)、氧(O)及氮(N),且O相對於N之比率為0.1以上且未達2.5。進而,第1低氧化鉻層13a較佳為分別以25~95原子%之含有率包含鉻(Cr),以5~45原子%之含有率包含氧(O),以2~35原子%之含有率包含氮(N),且O相對於N之比率為0.1以上且未達2.5。 形成第1高氧化鉻層13b之鉻系材料較佳為包含鉻(Cr)、氧(O)及氮(N),且O相對於N之比率為2.5以上且10以下。進而,第1高氧化鉻層13b較佳為分別以30~95原子%之含有率包含鉻(Cr),以7~50原子%之含有率包含氧(O),以2~25原子%之含有率包含氮(N),且O相對於N之比率為2.5以上且10以下。 第1低氧化鉻層13a及第1高氧化鉻層13b中所包含之Cr之含有率較佳為低於遮光層14中所包含之Cr。又,第1低氧化鉻層13a及第1高氧化鉻層13b中所包含之O及N之合計含有率較佳為7~75原子%。The chromium-based material forming the first low chromium oxide layer 13a preferably contains chromium (Cr), oxygen (O), and nitrogen (N), and the ratio of O to N is 0.1 or more and less than 2.5. Furthermore, the first low chromium oxide layer 13a preferably contains chromium (Cr) at a content rate of 25 to 95 at%, oxygen (O) at a content rate of 5 to 45 at%, and 2 to 35 at%. The content rate includes nitrogen (N), and the ratio of O to N is 0.1 or more and less than 2.5. The chromium-based material forming the first high chromium oxide layer 13b preferably contains chromium (Cr), oxygen (O), and nitrogen (N), and the ratio of O to N is 2.5 or more and 10 or less. Furthermore, the first high chromium oxide layer 13b preferably contains chromium (Cr) at a content rate of 30 to 95 at%, oxygen (O) at a content rate of 7 to 50 at%, and 2 to 25 at%. The content rate includes nitrogen (N), and the ratio of O to N is 2.5 or more and 10 or less. The content of Cr contained in the first low chromium oxide layer 13 a and the first high chromium oxide layer 13 b is preferably lower than the Cr contained in the light shielding layer 14. In addition, the total content of O and N contained in the first low-chromium oxide layer 13a and the first high-chromium oxide layer 13b is preferably 7 to 75 atomic %.

形成遮光層14之鉻材料較佳為主要包含Cr,且使Cr為97原子%以上且100原子%以下。除Cr以外,亦可包含O、N、C及F等,該等之合計含有率較佳為3原子%以下。The chromium material forming the light-shielding layer 14 preferably mainly contains Cr, and the Cr content is 97 atomic% or more and 100 atomic% or less. In addition to Cr, O, N, C, F, etc. may be included, and the total content of these is preferably 3 atomic% or less.

形成第2低氧化鉻層15a之鉻系材料較佳為包含鉻(Cr)、氧(O)及氮(N),且O相對於N之比率為0.1以上且未達2.5。進而,第2低氧化鉻層15a較佳為分別以25~95原子%之含有率包含鉻(Cr),以5~45原子%之含有率包含氧(O),以2~35原子%之含有率包含氮(N),且O相對於N之比率為0.1以上且未達2.5。 形成第2高氧化鉻層15b之鉻系材料較佳為包含鉻(Cr)、氧(O)及氮(N),且O相對於N之比率為2.5以上且10以下。進而,第2高氧化鉻層15b較佳為分別以30~70原子%之含有率包含鉻(Cr),以15~60原子%之含有率包含氧(O),以2~30原子%之含有率包含氮(N),且O相對於N之比率為2.5~10。 第2低氧化鉻層15a及第2高氧化鉻層15b中所包含之Cr之含有率較佳為低於遮光層14中所包含之Cr。又,第2低氧化鉻層15a及第2高氧化鉻層15b中所包含之O及N之合計含有率較佳為7~75原子%。The chromium-based material forming the second low chromium oxide layer 15a preferably contains chromium (Cr), oxygen (O), and nitrogen (N), and the ratio of O to N is 0.1 or more and less than 2.5. Furthermore, the second low chromium oxide layer 15a preferably contains chromium (Cr) at a content rate of 25 to 95 at%, oxygen (O) at a content rate of 5 to 45 at%, and 2 to 35 at%. The content rate includes nitrogen (N), and the ratio of O to N is 0.1 or more and less than 2.5. The chromium-based material forming the second high chromium oxide layer 15b preferably contains chromium (Cr), oxygen (O), and nitrogen (N), and the ratio of O to N is 2.5 or more and 10 or less. Furthermore, the second high chromium oxide layer 15b preferably contains chromium (Cr) at a content rate of 30 to 70 at%, oxygen (O) at a content rate of 15 to 60 at%, and 2 to 30 at%. The content rate includes nitrogen (N), and the ratio of O to N is 2.5-10. The content of Cr contained in the second low chromium oxide layer 15 a and the second high chromium oxide layer 15 b is preferably lower than the Cr contained in the light shielding layer 14. In addition, the total content of O and N contained in the second low-chromium oxide layer 15a and the second high-chromium oxide layer 15b is preferably 7 to 75 atomic %.

第1反射抑制層13及第2反射抑制層15較佳為分別具有O及N中之至少任一元素之含有率沿著膜厚方向連續地或者階段性地組成變化之區域。The first reflection suppression layer 13 and the second reflection suppression layer 15 preferably have regions in which the content of at least any element of O and N changes continuously or stepwise along the film thickness direction.

又,亦可於透明基板11與第1反射抑制層13之間、第1反射抑制層13與遮光層14之間、及遮光層14與第2反射抑制層15之間形成構成第1反射抑制層13、遮光層14及第2反射抑制層15之元素連續地組成梯度變化之梯度組成區域。In addition, it may be formed between the transparent substrate 11 and the first reflection suppression layer 13, between the first reflection suppression layer 13 and the light shielding layer 14, and between the light shielding layer 14 and the second reflection suppression layer 15. The elements of the layer 13, the light-shielding layer 14, and the second reflection suppression layer 15 continuously form a gradient composition area with a gradient change.

(關於膜厚) 於遮光膜12中,第1反射抑制層13、遮光層14、第2反射抑制層15各者之厚度並無特別限定,可根據遮光膜12所要求之光學密度及反射率適當調整。(About film thickness) In the light-shielding film 12, the thickness of each of the first reflection-inhibiting layer 13, the light-shielding layer 14, and the second reflection-inhibiting layer 15 is not particularly limited, and can be appropriately adjusted according to the optical density and reflectance required by the light-shielding film 12.

就兼顧第1反射抑制層13中之缺陷之抑制與背面反射率之降低之觀點而言,第1低氧化鉻層13a與第1高氧化鉻層13b之厚度分別較佳為設為10 nm以上且35 nm以下,該等合計所得之第1反射抑制層13之厚度較佳為設為20 nm以上且70 nm以下。又,期待第1低氧化鉻層13a與第1高氧化鉻層13b之厚度之比率較佳為第1高氧化鉻層:第1低氧化鉻層=1:7~1:1,進而較佳為第1高氧化鉻層:第1低氧化鉻層=1:5~1:2。From the viewpoint of achieving both suppression of defects in the first reflection suppression layer 13 and reduction of back surface reflectance, the thickness of the first low-chromium oxide layer 13a and the first high-chromium oxide layer 13b is preferably set to 10 nm or more. And 35 nm or less, the thickness of the first reflection suppression layer 13 obtained by these sums is preferably 20 nm or more and 70 nm or less. In addition, it is expected that the ratio of the thickness of the first low chromium oxide layer 13a to the first high chromium oxide layer 13b is preferably the first high chromium oxide layer: the first low chromium oxide layer = 1:7 to 1:1, and more preferably It is the first high chromium oxide layer: the first low chromium oxide layer=1:5 to 1:2.

遮光層14之厚度可根據遮光膜12所要求之光學密度適當變更。例如若為將光學密度設為3以上之情形,則可將遮光層14之厚度設為50 nm~200 nm。The thickness of the light-shielding layer 14 can be appropriately changed according to the optical density required by the light-shielding film 12. For example, if the optical density is set to 3 or more, the thickness of the light shielding layer 14 can be set to 50 nm to 200 nm.

第2反射抑制層15之厚度係以針對來自遮光膜12之正面側之曝光之光或描繪光可獲得特定之光學特性(正面反射率)之方式進行調整。具體而言,以對於來自遮光膜12之背面側之曝光之光之代表波長(例如365 nm~436 nm)成為10%以下之方式調整第2反射抑制層15中之第2低氧化鉻層15a、及第2高氧化鉻層15b之膜厚。就兼顧第2反射抑制層15中之缺陷之抑制與正面反射率之降低之觀點而言,第2低氧化鉻層15a之厚度與第2高氧化鉻層15b之厚度分別較佳為設為10 nm以上且35 nm以下,該等合計所得之第2反射抑制層15之厚度較佳為設為20 nm以上且70 nm以下。又,期待第2低氧化鉻層15a與第2高氧化鉻層15b之厚度之比率較佳為第2高氧化鉻層:第2低氧化鉻層=1:7~1:1,進而較佳為第2高氧化鉻層:第2低氧化鉻層=1:5~1:2。The thickness of the second reflection suppression layer 15 is adjusted in such a way that specific optical characteristics (frontal reflectance) can be obtained for exposure light or drawing light from the front side of the light-shielding film 12. Specifically, the second low chromium oxide layer 15a in the second reflection suppression layer 15 is adjusted so that the representative wavelength (for example, 365 nm to 436 nm) of the light exposed from the back side of the light shielding film 12 becomes 10% or less , And the film thickness of the second high chromium oxide layer 15b. From the viewpoint of achieving both suppression of defects in the second reflection suppression layer 15 and reduction of the frontal reflectance, the thickness of the second low chromium oxide layer 15a and the thickness of the second high chromium oxide layer 15b are preferably set to 10 respectively. nm or more and 35 nm or less, the thickness of the second reflection suppression layer 15 obtained by these totals is preferably 20 nm or more and 70 nm or less. In addition, it is expected that the thickness ratio of the second low chromium oxide layer 15a to the second high chromium oxide layer 15b is preferably the second high chromium oxide layer: the second low chromium oxide layer = 1:7 to 1:1, and more preferably It is the second high chromium oxide layer: the second low chromium oxide layer=1:5 to 1:2.

(光罩基底之光學特性) 光罩基底1具有如以下之光學特性。(Optical characteristics of the mask substrate) The mask substrate 1 has the following optical characteristics.

於對光罩基底1之遮光膜12之正面照射曝光之光或描繪光時所獲得之遮光膜12之正面之反射率光譜於曝光波長300 nm~436 nm之範圍內之代表波長下,正面反射率較佳為15%以下,更佳為12%以下,進而較佳為10%以下。進而較佳為遮光膜12之正面之反射光譜於曝光波長300 nm~436 nm之範圍內,正面反射率較佳為15%以下,更佳為12%以下,進而較佳為10%以下。或遮光膜12之正面之反射率光譜於曝光波長365 nm~436 nm之範圍內之代表波長下,正面反射率較佳為10%以下,更佳為7.5%以下,進而較佳為5%以下。進而較佳為遮光膜12之正面之反射率光譜於曝光波長365 nm~436 nm之範圍內,正面反射率較佳為10%以下,更佳為7.5%以下,進而較佳為5%以下。 又,於對光罩基底1之遮光膜12之背面照射曝光之光時所獲得之遮光膜12之背面之反射率光譜於曝光波長300 nm~436 nm之範圍內之代表波長下,背面反射率較佳為15%以下,更佳為12%以下,進而較佳為10%以下。進而較佳為遮光膜12之背面之反射光譜於曝光波長300 nm~436 nm之範圍內,背面反射率較佳為15%以下,更佳為12%以下,進而較佳為10%以下。又,遮光膜12之背面之反射率光譜於曝光波長365 nm~436 nm之範圍內之代表波長下,背面反射率較佳為10%以下,更佳為7.5%以下,進而較佳為5%以下。進而較佳為遮光膜12之背面之反射光譜於曝光波長365 nm~436 nm之範圍內,背面反射率較佳為10%以下,更佳為7.5%以下,進而較佳為5%以下。The reflectance spectrum of the front side of the light-shielding film 12 obtained by irradiating the front side of the light-shielding film 12 of the mask substrate 1 with exposure light or drawing light is at a representative wavelength within the exposure wavelength range of 300 nm to 436 nm, and front reflection The rate is preferably 15% or less, more preferably 12% or less, and still more preferably 10% or less. More preferably, the front reflection spectrum of the light-shielding film 12 is within the exposure wavelength range of 300 nm to 436 nm, and the front reflection rate is preferably 15% or less, more preferably 12% or less, and even more preferably 10% or less. Or the front reflectance spectrum of the light-shielding film 12 is at a representative wavelength in the exposure wavelength range of 365 nm to 436 nm. The front reflectance is preferably 10% or less, more preferably 7.5% or less, and more preferably 5% or less . More preferably, the reflectance spectrum of the front surface of the light shielding film 12 is within the range of the exposure wavelength from 365 nm to 436 nm, and the front reflectance is preferably 10% or less, more preferably 7.5% or less, and even more preferably 5% or less. Moreover, the reflectance spectrum of the back surface of the light-shielding film 12 obtained when the back surface of the light-shielding film 12 of the mask substrate 1 is irradiated with exposure light is at a representative wavelength in the range of exposure wavelength from 300 nm to 436 nm. It is preferably 15% or less, more preferably 12% or less, and still more preferably 10% or less. More preferably, the reflectance spectrum of the back surface of the light shielding film 12 is within the range of exposure wavelength 300 nm to 436 nm, and the back surface reflectance is preferably 15% or less, more preferably 12% or less, and still more preferably 10% or less. In addition, the reflectance spectrum of the back surface of the light-shielding film 12 is at a representative wavelength in the exposure wavelength range of 365 nm to 436 nm. The back surface reflectance is preferably 10% or less, more preferably 7.5% or less, and still more preferably 5% the following. More preferably, the reflectance spectrum of the back surface of the light-shielding film 12 is within the range of the exposure wavelength from 365 nm to 436 nm, and the back surface reflectance is preferably 10% or less, more preferably 7.5% or less, and still more preferably 5% or less.

又,光罩基底1之遮光膜12中之正面及背面之反射率於曝光波長300 nm~436 nm之範圍內或於365 nm~436 nm之範圍內,波長依存性較小。所謂波長依存性,表示反射率依存於曝光波長而變化,所謂波長依存性較小,表示反射率之最大值與最小值之差較小、即反射率之變化量(變動幅度)較小。具體而言,遮光膜12中之正面及背面之反射率之波長依存性於曝光波長300 nm~436 nm之範圍內,較佳為12%以下,更佳為10%以下。或遮光膜12中之正面及背面之反射率之波長依存性於曝光波長365 nm~436 nm之範圍內,較佳為5%以下,更佳為3%以下。In addition, the reflectivity of the front and back surfaces of the light shielding film 12 of the mask substrate 1 is within the range of exposure wavelength 300 nm-436 nm or within the range of 365 nm-436 nm, and the wavelength dependence is relatively small. The wavelength dependence means that the reflectance changes depending on the exposure wavelength. The smaller wavelength dependence means that the difference between the maximum value and the minimum value of the reflectance is small, that is, the change in reflectance (variation range) is small. Specifically, the wavelength dependence of the reflectance of the front and back of the light-shielding film 12 is within the range of the exposure wavelength from 300 nm to 436 nm, preferably 12% or less, more preferably 10% or less. Or the wavelength dependence of the reflectance of the front and back of the light-shielding film 12 is within the range of the exposure wavelength from 365 nm to 436 nm, preferably 5% or less, more preferably 3% or less.

又,光罩基底1可抑制遮光膜12之正面及背面之反射率(正面反射率、背面反射率)之面內不均,從而可提高正面及背面之反射率之面內均勻性。 具體而言,遮光膜12之正面反射率可抑制為3%以下(範圍)。遮光膜12之正面反射率之面內均勻性係基於使用反射率計對在光罩基底1之正面中將周緣部50 mm除外之光罩基底面內之11×11=121點進行測定所得之正面反射率之結果而算出。 又,遮光膜12之背面反射率可抑制為5%以下(範圍)。遮光膜12之背面反射率之面內均勻性係基於如下而計算:取代光罩基底1,而是於在光罩基底1之面內鋪滿有複數片之虛設基板(例如6英吋×6英吋之尺寸),形成構成遮光膜12之第1反射抑制層13、遮光層14及第2反射抑制層15,並使用反射率計測定形成於虛設基板之遮光膜12之背面之反射率所得之背面反射率之結果。 再者,所謂反射率之面內均勻性,係指該光罩基底之任意複數點上之反射率之最大值與最小值之差量。In addition, the mask substrate 1 can suppress the in-plane unevenness of the reflectance (front reflectance, back reflectance) of the front and back of the light-shielding film 12, thereby improving the in-plane uniformity of the reflectance of the front and back. Specifically, the front reflectance of the light-shielding film 12 can be suppressed to 3% or less (range). The in-plane uniformity of the front surface reflectance of the light-shielding film 12 is based on the measurement of 11×11=121 points on the front surface of the mask substrate 1 excluding the 50 mm peripheral edge of the mask substrate using a reflectance meter. Calculated from the result of frontal reflectivity. Moreover, the back surface reflectance of the light-shielding film 12 can be suppressed to 5% or less (range). The in-plane uniformity of the back surface reflectance of the light-shielding film 12 is calculated based on the following: instead of the mask base 1, instead of covering the surface of the mask base 1 with a plurality of dummy substrates (for example, 6 inches × 6 Inch size), the first reflection suppression layer 13, the light blocking layer 14, and the second reflection suppression layer 15 constituting the light shielding film 12 are formed, and the reflectance of the back surface of the light shielding film 12 formed on the dummy substrate is measured with a reflectometer. The result of back reflectivity. Furthermore, the so-called in-plane uniformity of reflectance refers to the difference between the maximum value and the minimum value of the reflectance at any plural points of the mask substrate.

<光罩基底之製造方法> 繼而,對上述光罩基底1之製造方法進行說明。<Manufacturing method of mask substrate> Next, the manufacturing method of the above-mentioned photomask substrate 1 is demonstrated.

(準備步驟) 準備對曝光之光實質上透明之透明基板11。再者,透明基板11可視需要進行研削步驟、研磨步驟等任意加工步驟而成為平坦且平滑之主表面。可於研磨後進行洗淨而將透明基板11之表面之異物及污染去除。作為洗淨,例如可使用硫酸、硫酸過氧化氫混合物(SPM)、氨、氨水過氧化氫混合物(APM)、OH自由基洗淨水、臭氧水、溫水等。(Preparatory steps) A transparent substrate 11 that is substantially transparent to the light to be exposed is prepared. Furthermore, the transparent substrate 11 may be subjected to any processing steps such as a grinding step and a polishing step as necessary to become a flat and smooth main surface. It can be cleaned after polishing to remove foreign matter and contamination on the surface of the transparent substrate 11. As washing, for example, sulfuric acid, sulfuric acid hydrogen peroxide mixture (SPM), ammonia, ammonia water hydrogen peroxide mixture (APM), OH radical washing water, ozone water, warm water, etc. can be used.

(第1反射抑制層之形成步驟) 繼而,於透明基板11上形成第1反射抑制層13。於本實施方式中,自透明基板11側起使第1低氧化鉻層13a及第1高氧化鉻層13b依序積層,形成第1反射抑制層13。(Steps of forming the first reflection suppression layer) Then, the first reflection suppression layer 13 is formed on the transparent substrate 11. In this embodiment, the first low-chromium oxide layer 13a and the first high-chromium oxide layer 13b are sequentially stacked from the transparent substrate 11 side to form the first reflection suppression layer 13.

於第1反射抑制層13之形成中,使用包含Cr之濺鍍靶、含有氧系氣體、氮系氣體之反應性氣體、及含稀有氣體之濺鍍氣體並藉由反應性濺鍍成膜。此時,作為成膜條件,濺鍍氣體中所包含之反應性氣體之流量選擇金屬模式之流量。In the formation of the first reflection suppression layer 13, a sputtering target containing Cr, a reactive gas containing oxygen-based gas and nitrogen-based gas, and a sputtering gas containing rare gas are used to form a film by reactive sputtering. At this time, as the film forming condition, the flow rate of the reactive gas contained in the sputtering gas selects the flow rate of the metal mode.

於反應性濺鍍中,於一面導入氧系氣體或氮系氣體等反應性氣體,一面使濺鍍靶放電時,對應於反應性氣體之流量而放電電漿之狀態變化,隨之成膜速度變化。於金屬模式下,藉由減少反應性氣體之比率,可減少反應性氣體對濺鍍靶表面之附著,從而使成膜速度加快。並且,於金屬模式下,由於反應性氣體之供給量較少,故而可形成例如相較於具有化學計量組成之膜而言含氧率(O含有率)或者含氮率(N含有率)之至少任一含有率降低之膜。In reactive sputtering, when a reactive gas such as an oxygen-based gas or a nitrogen-based gas is introduced into the sputtering target while the sputtering target is discharged, the state of the discharge plasma changes according to the flow rate of the reactive gas, and the film formation speed follows Variety. In the metal mode, by reducing the ratio of the reactive gas, the adhesion of the reactive gas to the surface of the sputtering target can be reduced, and the film formation speed can be accelerated. Moreover, in the metal mode, since the supply amount of the reactive gas is small, it is possible to form, for example, an oxygen content (O content) or a nitrogen content (N content) compared to a film with a stoichiometric composition. At least any film with reduced content.

就抑制第1反射抑制層13中之缺陷之觀點而言,較佳為降低成膜條件中之對濺鍍靶之施加功率。若降低對濺鍍靶之施加功率,則於導入氧系氣體或氮系氣體之反應性濺鍍中,可抑制濺鍍靶之微弧或異常放電,從而抑制第1反射抑制層13之缺陷之產生。作為用以成膜第1反射抑制層13之金屬模式之條件,例如可將氧系氣體之流量設為1~45 sccm,將氮系氣體之流量設為30~60 sccm,將烴系氣體之流量設為1~15 sccm,將稀有氣體之流量設為20~100 sccm。又,靶施加功率可設為1.0~6.0 kW。From the viewpoint of suppressing defects in the first reflection suppressing layer 13, it is preferable to reduce the power applied to the sputtering target in the film forming conditions. If the power applied to the sputtering target is reduced, the micro-arc or abnormal discharge of the sputtering target can be suppressed during reactive sputtering with oxygen-based gas or nitrogen-based gas introduced, thereby suppressing the defects of the first reflection suppression layer 13 produce. As the conditions for the metal mode for forming the first reflection suppression layer 13, for example, the flow rate of the oxygen-based gas is set to 1 to 45 sccm, the flow rate of the nitrogen-based gas is set to 30 to 60 sccm, and the flow rate of the hydrocarbon-based gas is set to The flow rate is set to 1-15 sccm, and the flow rate of the rare gas is set to 20-100 sccm. In addition, the target applied power can be set to 1.0 to 6.0 kW.

作為濺鍍靶,只要為包含鉻者即可,例如除鉻以外,亦可使用氧化鉻、氮化鉻、氮氧化鉻等鉻系材料。作為氧系氣體,例如可使用氧(O2 )、二氧化碳(CO2 )、氮氧化物氣體(N2 O、NO、NO2 )等。作為氮系氣體,可使用氮氣(N2 )等。例如亦可使用氦氣、氖氣、氬氣、氪氣體及氙氣等作為稀有氣體。再者,除上述反應性氣體以外,亦可供給烴系氣體,例如可使用甲烷氣體或丁烷氣體等。As the sputtering target, any one containing chromium may be used. For example, in addition to chromium, chromium-based materials such as chromium oxide, chromium nitride, and chromium oxynitride may also be used. As the oxygen-based gas, for example, oxygen (O 2 ), carbon dioxide (CO 2 ), nitrogen oxide gas (N 2 O, NO, NO 2 ), or the like can be used. As the nitrogen-based gas, nitrogen (N 2 ) or the like can be used. For example, helium, neon, argon, krypton, xenon, etc. can also be used as rare gases. Furthermore, in addition to the above-mentioned reactive gas, a hydrocarbon-based gas may be supplied. For example, methane gas or butane gas may be used.

於本實施方式中,將反應性氣體之流量及對濺鍍靶之施加功率設定為如成為金屬模式之條件,並使用包含Cr之濺鍍靶進行基於反應性濺鍍之成膜處理。藉此,於透明基板11上首先成膜O相對於N之比率相對較小之第1低氧化鉻層13a,並於其上成膜O相對於N之比率相對較大之第1高氧化鉻層13b,藉此形成第1反射抑制層13。第1低氧化鉻層13a係以金屬模式且低功率且以與第1高氧化鉻層13b相比O含有率降低之方式成膜。第1高氧化鉻層13b係以金屬模式且低功率且以與第1低氧化鉻層13a相比O含有率增高之方式成膜。再者,金屬模式下之成膜條件例如可參照日本專利特開2019-20712等進行設定。In this embodiment, the flow rate of the reactive gas and the power applied to the sputtering target are set to the conditions such as the metal mode, and the sputtering target containing Cr is used to perform the film forming process based on the reactive sputtering. Thereby, a first low-chromium oxide layer 13a with a relatively small ratio of O to N is first formed on the transparent substrate 11, and a first high-chromium oxide layer 13a with a relatively large ratio of O to N is formed thereon The layer 13b thereby forms the first reflection suppression layer 13. The first low chromium oxide layer 13a is formed in a metal mode with low power and a lower O content than the first high chromium oxide layer 13b. The first high chromium oxide layer 13b is formed in a metal mode, low power, and so that the O content is higher than that of the first low chromium oxide layer 13a. Furthermore, the film formation conditions in the metal mode can be set with reference to Japanese Patent Laid-Open No. 2019-20712, etc., for example.

再者,於自第1低氧化鉻層13a切換至第1高氧化鉻層13b之成膜時,為了使O含有率及N含有率變化,可適當變更反應性氣體之種類或流量、反應性氣體中之氧系氣體或氮系氣體之比率等。又,亦可變更氣體供給口之配置或氣體供給方法等。又,可對應於各層之厚度適當變更成膜時間。In addition, when switching from the first low chromium oxide layer 13a to the first high chromium oxide layer 13b for film formation, in order to change the O content and N content, the type, flow rate, and reactivity of the reactive gas can be appropriately changed The ratio of oxygen-based gas or nitrogen-based gas in the gas, etc. In addition, it is also possible to change the arrangement of the gas supply port or the gas supply method. In addition, the film formation time can be appropriately changed in accordance with the thickness of each layer.

(遮光層之形成步驟) 繼而,於第1反射抑制層13上形成遮光層14。遮光層14之形成係藉由使用包含Cr之濺鍍靶、及含稀有氣體之濺鍍氣體之濺鍍進行成膜。此時,作為成膜條件,濺鍍氣體中所包含之反應性氣體之流量選擇金屬模式之流量。(Steps of forming the light-shielding layer) Then, a light-shielding layer 14 is formed on the first reflection suppression layer 13. The light-shielding layer 14 is formed by sputtering using a sputtering target containing Cr and a sputtering gas containing a rare gas. At this time, as the film forming condition, the flow rate of the reactive gas contained in the sputtering gas selects the flow rate of the metal mode.

作為濺鍍靶,只要為包含鉻者即可。就使遮光膜12之正面及背面之反射率之面內均勻性良好之觀點而言,較佳為設為包含鉻之濺鍍靶。稀有氣體例如亦可使用氦氣、氖氣、氬氣、氪氣及氙氣等。再者,亦可於不脫離本發明之效果之範圍內,除上述稀有氣體以外亦供給氧系氣體、氮系氣體、烴系氣體。As a sputtering target, what is necessary is just to contain chromium. From the viewpoint of making the in-plane uniformity of the reflectance of the front and back of the light-shielding film 12 good, it is preferable to use a sputtering target containing chromium. As the rare gas, for example, helium, neon, argon, krypton, xenon, etc. can also be used. Furthermore, it is also possible to supply oxygen-based gas, nitrogen-based gas, and hydrocarbon-based gas in addition to the above-mentioned rare gas without departing from the effect of the present invention.

於本實施方式中,將反應性氣體之流量及濺鍍靶施加功率設定為如金屬模式之條件,並使用包含Cr之濺鍍靶進行濺鍍。藉此,於第1反射抑制層13上形成主要包含Cr之遮光層14。In this embodiment, the flow rate of the reactive gas and the applied power of the sputtering target are set to the conditions of the metal mode, and the sputtering target containing Cr is used for sputtering. Thereby, the light-shielding layer 14 mainly containing Cr is formed on the first reflection suppression layer 13.

再者,作為遮光層14之成膜條件,例如可將稀有氣體之流量設為60~200 sccm。又,靶施加功率可設為3.0~10.0 kW。In addition, as the film forming condition of the light shielding layer 14, the flow rate of the rare gas may be 60 to 200 sccm, for example. In addition, the target applied power can be set to 3.0 to 10.0 kW.

(第2反射抑制層之形成步驟) 繼而,於遮光層14上形成第2反射抑制層15。第2反射抑制層15之形成與第1反射抑制層13同樣地,將反應性氣體之流量及對濺鍍靶之施加功率設定為如金屬模式之條件,並使用包含Cr之濺鍍靶,利用反應性濺鍍進行成膜。藉此,於遮光層14上使O相對於N之比率相對較小之第2低氧化鉻層15a成膜,並於其上使O相對於N之比率相對較大之第2高氧化鉻層15b成膜,藉此形成第2反射抑制層15。第2低氧化鉻層15a係以金屬模式且低功率,按與第2高氧化鉻層15b相比O含有率降低之方式成膜。第2高氧化鉻層15b係以金屬模式且低功率,按與第2低氧化鉻層15a相比O含有率增高之方式成膜。(Steps of forming the second reflection suppression layer) Then, the second reflection suppression layer 15 is formed on the light shielding layer 14. The formation of the second reflection suppression layer 15 is the same as that of the first reflection suppression layer 13. The flow rate of the reactive gas and the power applied to the sputtering target are set to the conditions of the metal mode, and the sputtering target containing Cr is used. Reactive sputtering performs film formation. Thereby, a second low chromium oxide layer 15a with a relatively small ratio of O to N is formed on the light shielding layer 14, and a second high chromium oxide layer with a relatively large ratio of O to N is formed on it 15b is formed into a film, thereby forming the second reflection suppression layer 15. The second low chromium oxide layer 15a is formed in a metallic mode and low power, so that the O content is lower than that of the second high chromium oxide layer 15b. The second high chromium oxide layer 15b is formed in a metal mode with low power, and is formed so that the O content rate is higher than that of the second low chromium oxide layer 15a.

作為用以使第2反射抑制層15成膜之金屬模式之條件,例如可將氧系氣體之流量設為1~45 sccm,將氮系氣體之流量設為30~60 sccm,將烴系氣體之流量設為1~15 sccm,將稀有氣體之流量設為20~100 sccm。又,靶施加功率可設為1.0~6.0 kW。As the conditions of the metal mode for forming the second reflection suppression layer 15, for example, the flow rate of the oxygen-based gas is set to 1 to 45 sccm, the flow rate of the nitrogen-based gas is set to 30 to 60 sccm, and the hydrocarbon-based gas The flow rate is set to 1-15 sccm, and the flow rate of rare gas is set to 20-100 sccm. In addition, the target applied power can be set to 1.0 to 6.0 kW.

再者,於自第2低氧化鉻層15a切換至第1高氧化鉻層13b之成膜時,與第1反射抑制層13同樣地,可適當變更反應性氣體之種類或流量、反應性氣體中之氧系氣體或氮系氣體之比率等。又,亦可變更氣體供給口之配置或氣體供給方法等。Furthermore, when switching from the second low chromium oxide layer 15a to the first high chromium oxide layer 13b for film formation, similarly to the first reflection suppression layer 13, the type or flow rate of the reactive gas and the reactive gas can be appropriately changed The ratio of oxygen-based gas or nitrogen-based gas, etc. In addition, it is also possible to change the arrangement of the gas supply port or the gas supply method.

藉由以上獲得本實施方式之光罩基底1。Through the above, the photomask substrate 1 of this embodiment is obtained.

再者,遮光膜12中之各層之成膜可使用直列型濺鍍裝置並以in-situ(當場)進行。於並非直列型之情形時,於各層之成膜後,必須將透明基板11拆卸至裝置外,透明基板11曝露於大氣中而有時各層會經表面氧化或表面碳化。其結果為,有時會導致遮光膜12對曝光之光之反射率或蝕刻速率變化。關於該情況,若為直列型,則可於不將透明基板11拆卸至裝置外而曝露於大氣中之情況下連續地成膜各層,因此可抑制元素向遮光膜12之無意滲入。Furthermore, the film formation of each layer in the light-shielding film 12 can be performed in-situ using an in-line sputtering device. In the case of non-in-line type, after the formation of each layer, the transparent substrate 11 must be disassembled to the outside of the device. The transparent substrate 11 is exposed to the atmosphere and sometimes each layer may undergo surface oxidation or surface carbonization. As a result, sometimes the reflectance of the light shielding film 12 to the exposed light or the etching rate may change. In this case, if it is an in-line type, each layer can be continuously formed without removing the transparent substrate 11 to the outside of the device and exposing to the atmosphere. Therefore, it is possible to suppress unintentional infiltration of elements into the light-shielding film 12.

又,於使用直列型濺鍍裝置成膜遮光膜12之情形時,因第1反射抑制層13、遮光層14、第2反射抑制層15之各層之間具有連續地組成梯度變化之梯度組成區域(過渡層),故可使使用光罩基底並藉由蝕刻(尤其是濕式蝕刻)而形成之遮光膜圖案之剖面平滑且接近垂直,故而較佳。In addition, when the light-shielding film 12 is formed using an in-line sputtering device, the first reflection-inhibiting layer 13, the light-shielding layer 14, and the second reflection-inhibiting layer 15 have a gradient composition area with a continuous composition gradient among the layers. (Transition layer), so that the cross-section of the light-shielding film pattern formed by etching (especially wet etching) using a photomask substrate can be smooth and close to vertical, which is preferable.

<光罩之製造方法> 繼而,使用上述光罩基底1對製造光罩之方法進行說明。<Manufacturing method of photomask> Next, a method of manufacturing a photomask will be described using the above-mentioned photomask substrate 1.

(抗蝕膜之形成步驟) 首先,於光罩基底1之遮光膜12中之第2反射抑制層15上塗佈抗蝕劑,並乾燥而形成抗蝕膜。作為抗蝕劑,必須對應於所使用之描繪裝置選擇適當者,可使用正型或負型抗蝕劑。(Steps of forming resist film) First, a resist is coated on the second reflection suppression layer 15 in the light-shielding film 12 of the photomask base 1, and dried to form a resist film. As the resist, an appropriate one must be selected corresponding to the drawing device used, and either a positive type or a negative type resist can be used.

(抗蝕圖案之形成步驟) 繼而,使用描繪裝置於抗蝕膜描繪特定之圖案。通常,於製作顯示裝置製造用之光罩時使用雷射描繪裝置。描繪後,對抗蝕膜實施顯影及清洗,藉此形成特定之抗蝕圖案。(Steps of forming resist pattern) Then, a drawing device is used to draw a specific pattern on the resist film. Generally, a laser drawing device is used when making a mask for manufacturing a display device. After drawing, the resist film is developed and cleaned to form a specific resist pattern.

本實施方式係以降低第2反射抑制層15之反射率之方式構成,因此於在抗蝕膜描繪圖案時,可減少描繪光(雷射光)之反射。藉此,可形成圖案精度較高之抗蝕圖案,隨之可形成尺寸精度較高之遮光膜圖案。The present embodiment is configured to reduce the reflectance of the second reflection suppression layer 15, so when the pattern is drawn on the resist film, the reflection of drawing light (laser light) can be reduced. Thereby, a resist pattern with higher pattern accuracy can be formed, and accordingly, a light-shielding film pattern with higher dimensional accuracy can be formed.

(遮光膜圖案之形成步驟) 繼而,將抗蝕圖案作為遮罩對遮光膜12進行蝕刻,藉此形成遮光膜圖案。蝕刻可為濕式蝕刻,亦可為乾式蝕刻。通常,於顯示裝置製造用之光罩中進行濕式蝕刻,作為濕式蝕刻中使用之蝕刻液(蝕刻劑),例如可使用包含硝酸鈰銨及過氯酸之鉻蝕刻液。(Steps of forming shading film pattern) Then, the light-shielding film 12 is etched using the resist pattern as a mask, thereby forming a light-shielding film pattern. The etching may be wet etching or dry etching. Generally, wet etching is performed in a photomask for manufacturing a display device. As an etching solution (etchant) used in wet etching, for example, a chromium etching solution containing cerium ammonium nitrate and perchloric acid can be used.

本實施方式係以使第1反射抑制層13、遮光層14及第2反射抑制層15之蝕刻速率於遮光膜12之厚度方向上一致之方式調整各層之組成,因此可使經濕式蝕刻時之剖面形狀、即遮光膜圖案之剖面形狀相對於透明基板11接近垂直,從而可獲得較高之CD均勻性。In this embodiment, the composition of each layer is adjusted so that the etching rates of the first reflection suppression layer 13, the light shielding layer 14, and the second reflection suppression layer 15 are consistent in the thickness direction of the light shielding film 12. The cross-sectional shape, that is, the cross-sectional shape of the light-shielding film pattern is nearly perpendicular to the transparent substrate 11, so that a high CD uniformity can be obtained.

(剝離步驟) 繼而,將抗蝕圖案剝離,獲得於透明基板11上形成有遮光膜圖案(遮光膜圖案)之光罩。(Peeling step) Then, the resist pattern is peeled off, and a mask having a light-shielding film pattern (light-shielding film pattern) formed on the transparent substrate 11 is obtained.

藉由以上獲得本實施方式之光罩。Through the above, the photomask of this embodiment is obtained.

<顯示裝置之製造方法> 繼而,對使用上述光罩製造顯示裝置之方法進行說明。<Manufacturing method of display device> Next, a method of manufacturing a display device using the above-mentioned photomask will be described.

(準備步驟) 首先,準備於顯示裝置之基板上形成有抗蝕膜之附抗蝕膜之基板。繼而,將藉由上述製造方法而獲得之光罩以隔著曝光裝置之投影光學系統與附抗蝕膜之基板之抗蝕膜對向之方式載於曝光裝置之遮罩台。(Preparatory steps) First, a substrate with a resist film in which a resist film is formed on the substrate of the display device is prepared. Then, the photomask obtained by the above-mentioned manufacturing method is placed on the mask stage of the exposure apparatus so that the projection optical system of the exposure apparatus and the resist film of the substrate with the resist film are opposed to each other.

(曝光步驟(圖案轉印步驟)) 繼而,進行對光罩照射曝光之光而將圖案轉印至形成於顯示裝置之基板上之抗蝕膜之抗蝕劑曝光步驟。 曝光之光例如使用選自300 nm~436 nm之波長頻帶中之單波長之光(j線(波長313 nm)、波長334 nm、i線(波長365 nm)、h線(波長405 nm)、g線(波長436 nm)等)或包含複數個波長之光(例如j線(波長313 nm)、波長334 nm、i線(波長365 nm)、h線(405 nm)、g線(波長436 nm))之複合光。若為使用大型光罩之情形,則就光量之觀點而言,可使用複合光作為曝光之光。 本實施方式係使用遮光膜圖案(遮光膜圖案)之正面及背面之反射率降低且該等反射率之面內均勻性較高之光罩製造顯示裝置(顯示面板),因此可形成精度較高之轉印圖案。(Exposure step (pattern transfer step)) Then, a resist exposure step of irradiating the photomask with exposure light to transfer the pattern to the resist film formed on the substrate of the display device is performed. The light for exposure is, for example, light of a single wavelength selected from the wavelength band of 300 nm to 436 nm (j-line (wavelength 313 nm), wavelength 334 nm, i-line (wavelength 365 nm), h-line (wavelength 405 nm), g-line (wavelength 436 nm), etc.) or light containing multiple wavelengths (e.g. j-line (wavelength 313 nm), wavelength 334 nm, i-line (wavelength 365 nm), h-line (405 nm), g-line (wavelength 436 nm)) of composite light. In the case of using a large mask, from the viewpoint of the amount of light, composite light can be used as the light for exposure. In this embodiment, a display device (display panel) is manufactured using a mask with a lower reflectivity of the front and back surfaces of the light-shielding film pattern (light-shielding film pattern) and high in-plane uniformity of the reflectance. Therefore, a high-precision transfer can be formed. Printed patterns.

<本實施方式之效果> 根據本實施方式,實現以下所示之一個或複數個效果。<Effects of this embodiment> According to this embodiment, one or more of the following effects are achieved.

(a)本實施方式之光罩基底1於遮光膜12中,使氧化相對較少之第1低氧化鉻層13a與氧化相對較多之第1高氧化鉻層13b積層而構成第1反射抑制層13。藉此,可減少第1反射抑制層13中之缺陷、降低遮光膜12之背面之反射率。並且,於光罩基底1中可抑制背面反射率之面內不均而提高背面反射率之均勻性。(a) In the mask base 1 of this embodiment, in the light-shielding film 12, a first low-chromium oxide layer 13a with relatively little oxidation and a first high-chromium oxide layer 13b with relatively high oxidation are laminated to form a first reflection suppression Layer 13. Thereby, the defects in the first reflection suppression layer 13 can be reduced, and the reflectivity of the back surface of the light-shielding film 12 can be reduced. In addition, the in-plane unevenness of the back surface reflectance can be suppressed in the mask substrate 1, and the uniformity of the back surface reflectance can be improved.

(b)又,使氧化相對較少之第2低氧化鉻層15a與氧化相對較多之第2高氧化鉻層15b積層而構成第2反射抑制層15。藉此,可減少第2反射抑制層15中之缺陷、降低遮光膜12之正面之反射率。並且,於光罩基底1中可抑制正面反射率之面內不均而提高正面反射率之均勻性。(b) In addition, the second low chromium oxide layer 15a, which is relatively less oxidized, and the second high chromium oxide layer 15b, which is relatively more oxidized, are laminated to form the second reflection suppression layer 15. Thereby, the defects in the second reflection suppression layer 15 can be reduced, and the reflectivity of the front surface of the light-shielding film 12 can be reduced. In addition, the in-plane unevenness of the front reflectance can be suppressed in the mask substrate 1 and the uniformity of the front reflectance can be improved.

(c)較佳為第1低氧化鉻層13a分別以25~95原子%之含有率包含Cr,以5~45原子%之含有率包含O,以2~35原子%之含有率包含N,且O相對於N之比率未達2.5,第1高氧化鉻層13b分別以30~95原子%之含有率包含Cr,以7~50原子%之含有率包含O,以2~25原子%之含有率包含N,且O相對於N之比率為2.5~10。又,較佳為第2低氧化鉻層15a分別以25~95原子%之含有率包含Cr,以5~45原子%之含有率包含O,以2~35原子%之含有率包含N,且O相對於N之比率未達2.5,第2高氧化鉻層15b分別以30~70原子%之含有率包含Cr,以15~60原子%之含有率包含O,以2~30原子%之含有率包含N,且O相對於N之比率為2.5~10。藉由以此種組成構成各層,可降低遮光膜12之正面及背面之反射率(對曝光之光之代表波長為10%以下)並減少缺陷。並且,可使遮光膜12之各層之蝕刻速率一致,因此可使遮光膜圖案之剖面形狀更接近垂直。(c) It is preferable that the first low chromium oxide layer 13a contains Cr at a content rate of 25 to 95 at%, O at a content rate of 5 to 45 at%, and N at a content rate of 2 to 35 at%. And the ratio of O to N is less than 2.5, and the first high chromium oxide layer 13b contains Cr at a content rate of 30 to 95 at%, and O at a content rate of 7 to 50 at%, and 2 to 25 at%. The content rate includes N, and the ratio of O to N is 2.5-10. In addition, it is preferable that the second low chromium oxide layer 15a contains Cr at a content rate of 25 to 95 at%, O at a content rate of 5 to 45 at%, and N at a content rate of 2 to 35 at%, and The ratio of O to N is less than 2.5, and the second high chromium oxide layer 15b contains Cr at a content rate of 30 to 70 at%, O at a content rate of 15 to 60 at%, and a content of 2 to 30 at%. The rate includes N, and the ratio of O to N is 2.5-10. By forming each layer with such a composition, the reflectivity of the front and back of the light-shielding film 12 can be reduced (the representative wavelength of the exposure light is less than 10%) and defects can be reduced. In addition, the etching rate of each layer of the light-shielding film 12 can be made uniform, so that the cross-sectional shape of the light-shielding film pattern can be closer to vertical.

(d)第1反射抑制層13及第2反射抑制層15較佳為分別具有O及N中之至少任一元素之含有率沿著膜厚方向連續地或者階段地組成變化之區域。藉由使第1反射抑制層13及第2反射抑制層15之各層變化組成,可降低各層內之蝕刻速率之差而使遮光膜圖案之剖面形狀更接近垂直。(d) The first reflection suppression layer 13 and the second reflection suppression layer 15 preferably have regions in which the content of at least any element of O and N changes continuously or stepwise along the film thickness direction. By changing the composition of each layer of the first reflection suppression layer 13 and the second reflection suppression layer 15, the difference in the etching rate in each layer can be reduced, and the cross-sectional shape of the light-shielding film pattern can be closer to vertical.

(e)遮光層14較佳為鉻之含有率為97原子%~100原子%。藉由以實質上不包含O、N、F之鉻構成遮光層14,可抑制因包含O、N、F而產生之面內組成之不均。藉此,可使遮光膜12之正面反射率及背面反射率於光罩基底面內更均勻。(e) The light-shielding layer 14 preferably has a chromium content of 97 atomic% to 100 atomic %. By forming the light-shielding layer 14 with chromium that does not substantially contain O, N, and F, the unevenness of the in-plane composition due to the inclusion of O, N, and F can be suppressed. Thereby, the front reflectivity and the back reflectivity of the light shielding film 12 can be made more uniform in the base surface of the photomask.

(f)較佳為於第1反射抑制層13中,第1高氧化鉻層13b中之O相對於N之比率為2.5~10。藉由以成為上述O/N比之方式構成,可降低第1反射抑制層13之反射率,並且可減少與其他層(遮光層:尤其是鉻之含有率為97~100原子%)之蝕刻速率之差。(f) Preferably, in the first reflection suppression layer 13, the ratio of O to N in the first high chromium oxide layer 13b is 2.5-10. By forming the above-mentioned O/N ratio, the reflectance of the first reflection suppression layer 13 can be reduced, and the etching with other layers (light-shielding layer: especially the content of chromium is 97-100 atomic%) can be reduced. The difference in speed.

(g)較佳為於第2反射抑制層15中,第2高氧化鉻層15b中之O相對於N之比率為2.5~10。藉由以成為上述O/N比之方式構成,可降低第2反射抑制層15之反射率。又,可提高與形成於第2低氧化鉻層15a之正面之抗蝕膜之密接性,從而可使遮光膜圖案之剖面形狀更穩定地接近垂直。(g) Preferably, in the second reflection suppression layer 15, the ratio of O to N in the second high chromium oxide layer 15b is 2.5-10. By configuring to achieve the above-mentioned O/N ratio, the reflectance of the second reflection suppression layer 15 can be reduced. In addition, the adhesion with the resist film formed on the front surface of the second low chromium oxide layer 15a can be improved, so that the cross-sectional shape of the light-shielding film pattern can be more stably close to vertical.

(h)較佳為第1反射抑制層13及第2反射抑制層15之至少一者進而包含C。藉此,可減小第1反射抑制層13及第2反射抑制層15與遮光層14之蝕刻速率之差。尤其是於遮光層14之鉻含有率為97原子%~100原子%時,可使差更小。(h) It is preferable that at least one of the first reflection suppression layer 13 and the second reflection suppression layer 15 further includes C. Thereby, the difference in the etching rate between the first reflection suppression layer 13 and the second reflection suppression layer 15 and the light shielding layer 14 can be reduced. Especially when the chromium content of the light-shielding layer 14 is 97 atomic% to 100 atomic %, the difference can be made smaller.

(i)光罩基底1具有如下光學特性:藉由具備上述遮光膜12而曝光波長300 nm~436 nm之範圍內之正面及背面之反射率均為15%以下,上述波長範圍內之正面反射率及背面反射率各者之波長依存性為12%以下。又,光罩基底1具有如下光學特性:藉由具備上述遮光膜12而曝光波長365 nm~436 nm之範圍內之正面及背面之反射率均為10%以下,上述波長範圍內之正面反射率及背面反射率各者之波長依存性為5%以下。根據此種光罩基底1,於作為光罩照射曝光之光時,遮光膜12可遍及曝光波長300 nm~436 nm之所有波長頻帶或曝光波長365 nm~436 nm之所有波長頻帶抑制正面及背面之光之反射,因此可降低正面及背面之反射光之合計光量。尤其是可將遮光膜12之背面反射率之波長依存性設為5%以下而於上述波長範圍之整個頻帶中平均降低背面反射率,因此可抑制朝向光罩背面之回光。該結果為,可抑制使用光罩製造顯示裝置時之因光罩正面及背面之光之反射而導致之轉印圖案精度之降低。(i) The photomask substrate 1 has the following optical characteristics: by providing the above-mentioned light-shielding film 12, the reflectivity of the front and back surfaces in the exposure wavelength range of 300 nm to 436 nm are both 15% or less, and the front surface reflection in the above-mentioned wavelength range The wavelength dependence of each of the reflectance and the back reflectance is 12% or less. In addition, the photomask substrate 1 has the following optical characteristics: by providing the above-mentioned light-shielding film 12, the reflectance of the front and back surfaces in the exposure wavelength range of 365 nm to 436 nm is 10% or less, and the reflectance of the front surface in the above-mentioned wavelength range The wavelength dependence of each of and the back reflectance is 5% or less. According to this photomask substrate 1, when irradiating exposure light as a photomask, the light-shielding film 12 can cover all wavelength bands with an exposure wavelength of 300 nm to 436 nm or all wavelength bands with an exposure wavelength of 365 nm to 436 nm. Suppress the front and back sides The reflection of light can reduce the total amount of reflected light on the front and back. In particular, the wavelength dependence of the back surface reflectance of the light shielding film 12 can be set to 5% or less, and the back surface reflectance can be averagely reduced in the entire frequency band of the above-mentioned wavelength range, so that the back light toward the back surface of the mask can be suppressed. As a result, it is possible to suppress the reduction in the accuracy of the transfer pattern caused by the reflection of light on the front and back of the mask when the display device is manufactured using the mask.

(j)較佳為光罩基底1於曝光波長300 nm~436 nm之範圍之整個頻帶中,背面反射率小於正面反射率。或較佳為光罩基底1於曝光波長365 nm~436 nm之範圍之整個頻帶中,背面反射率小於正面反射率。藉此,可遍及範圍廣泛之波長頻帶抑制曝光之光之反射,而進一步降低曝光之光之反射之合計光量。(j) It is preferable that the back reflectance of the photomask substrate 1 is lower than the front reflectance in the entire frequency band of the exposure wavelength range of 300 nm to 436 nm. Or preferably, the back reflectance of the photomask substrate 1 is lower than the front reflectance in the entire frequency band of the exposure wavelength range of 365 nm to 436 nm. As a result, the reflection of the exposed light can be suppressed over a wide range of wavelength bands, and the total amount of the reflected light of the exposure can be further reduced.

(k)較佳為光罩基底1於曝光波長300 nm~436 nm之範圍內,背面反射率之波長依存性小於正面反射率之波長依存性。或較佳為光罩基底1於曝光波長365 nm~436 nm之範圍之整個頻帶中,背面反射率之波長依存性小於正面反射率之波長依存性。即,較佳為於上述波長範圍內,背面反射率之變化量小於正面反射率之變化量。藉此,可進而抑制光罩背面之回光,從而可進一步減少轉印圖案精度之降低。(k) It is preferable that the wavelength dependence of the back reflectance of the mask substrate 1 is within the range of 300 nm to 436 nm of exposure wavelength than the wavelength dependence of the front reflectance. Or it is preferable that the wavelength dependence of the back reflectance of the mask substrate 1 in the entire frequency band of the exposure wavelength range of 365 nm to 436 nm is smaller than the wavelength dependence of the front reflectance. That is, it is preferable that within the above-mentioned wavelength range, the amount of change in back reflectance is smaller than the amount of change in front reflectance. Thereby, the return light on the back of the photomask can be further suppressed, so that the reduction in the accuracy of the transfer pattern can be further reduced.

(l)根據光罩基底1,由於遮光膜12之正面側之正面反射率較低,故於遮光膜12上設置抗蝕膜並藉由描繪・顯影步驟形成抗蝕圖案時,可降低描繪光於遮光膜12正面之反射。藉此,可提高抗蝕圖案之尺寸精度,從而提高由此形成之光罩之遮光膜圖案之尺寸精度。具體而言,可提高遮光膜圖案之CD均勻性,從而可形成75 nm以下之高精度之遮光膜圖案。(l) According to the photomask base 1, since the front surface reflectance of the light-shielding film 12 is low, when a resist film is provided on the light-shielding film 12 and the resist pattern is formed by the drawing and development steps, the drawing light can be reduced Reflection on the front side of the shading film 12. Thereby, the dimensional accuracy of the resist pattern can be improved, and the dimensional accuracy of the light-shielding film pattern of the photomask thus formed can be improved. Specifically, the CD uniformity of the light-shielding film pattern can be improved, so that a high-precision light-shielding film pattern below 75 nm can be formed.

(m)由光罩基底1製造之光罩由於遮光膜圖案為高精度,又,遮光膜圖案之正面及背面之反射率較小,且反射率之面內均勻性較高,故於對被轉印體轉印圖案時,可獲得較高之轉印特性。(m) The photomask made from the photomask substrate 1 is highly accurate due to the high precision of the light-shielding film pattern, and the reflectivity of the front and back of the light-shielding film pattern is small, and the in-plane uniformity of the reflectivity is relatively high. When the transfer body transfers the pattern, higher transfer characteristics can be obtained.

<其他實施方式> 以上,對本發明之一實施方式具體地進行了說明,但本發明並不限定於上述實施方式,可於不脫離其主旨之範圍內適當變更。<Other embodiments> As mentioned above, one embodiment of the present invention has been described in detail, but the present invention is not limited to the above-mentioned embodiment, and can be appropriately changed without departing from the gist of the present invention.

於上述實施方式中,對直接於透明基板11之上設置遮光膜12之情形進行了說明,但本發明並不限定於此。例如,亦可為於透明基板11與遮光膜12之間設置有光學密度低於遮光膜12之半透光膜之光罩基底。於在該透明基板11上形成有半透光膜及遮光膜12之光罩基底中,亦較佳為於曝光波長300 nm~436 nm之範圍內,半透光膜對上述曝光之光之背面反射率為15%以下,遮光膜之正面反射率為15%以下。又,於在透明基板11上形成有半透光膜與遮光膜12之光罩基底中,較佳為於曝光波長365 nm~436 nm之範圍內,半透光膜對上述曝光之光之背面反射率為10%以下,遮光膜之正面反射率為10%以下。該光罩基底可用作具有削減製造顯示裝置時所使用之光罩片數之效果的灰階光罩(或graytone mask)之光罩基底。該灰階光罩(或graytone mask)中之遮光膜圖案成為半透光膜圖案及/或遮光膜圖案。In the above-mentioned embodiment, the case where the light-shielding film 12 is directly provided on the transparent substrate 11 has been described, but the present invention is not limited to this. For example, it may also be a mask base provided with a semi-transmissive film having an optical density lower than that of the light-shielding film 12 between the transparent substrate 11 and the light-shielding film 12. In the mask base on which the semi-transmissive film and the light-shielding film 12 are formed on the transparent substrate 11, it is also preferable that the semi-transparent film is in the range of the exposure wavelength of 300 nm to 436 nm. The reflectivity is below 15%, and the frontal reflectivity of the shading film is below 15%. In addition, in the mask base on which the semi-transparent film and the light-shielding film 12 are formed on the transparent substrate 11, it is preferable that the semi-transparent film faces the back of the exposed light within the range of the exposure wavelength of 365 nm to 436 nm. The reflectivity is below 10%, and the front reflectivity of the shading film is below 10%. The mask substrate can be used as a gray-scale mask (or graytone mask) with the effect of reducing the number of mask sheets used in manufacturing the display device. The light-shielding film pattern in the gray-scale mask (or graytone mask) becomes a semi-transmissive film pattern and/or a light-shielding film pattern.

又,亦可為於透明基板11與遮光膜12之間設置有使透過光之相位偏移之相位偏移膜來代替半透光膜之光罩基底。於在該透明基板11上形成有相位偏移膜與遮光膜12之光罩基底中,亦較佳為於曝光波長300 nm~436 nm之範圍內,相位偏移膜對上述曝光之光之背面反射率為15%以下,遮光膜之正面反射率為15%以下。又,於在透明基板11上形成有相位偏移膜與遮光膜12之光罩基底中,較佳為於曝光波長365 nm~436 nm之範圍內,相位偏移膜對上述曝光之光之背面反射率為10%以下,遮光膜之正面反射率為10%以下。該光罩基底可用作具有相位偏移效果所帶來之較高之圖案解像性之效果的相位偏移光罩。該相位偏移光罩中之遮光膜圖案成為相位偏移膜圖案或相位偏移膜圖案及遮光膜圖案。In addition, a phase shift film that shifts the phase of transmitted light may be provided between the transparent substrate 11 and the light-shielding film 12 instead of the photomask base of the semi-transparent film. In the mask base on which the phase shift film and the light-shielding film 12 are formed on the transparent substrate 11, it is also preferable that the phase shift film is in the range of the exposure wavelength of 300 nm to 436 nm. The reflectivity is below 15%, and the frontal reflectivity of the shading film is below 15%. In addition, in the photomask base on which the phase shift film and the light shielding film 12 are formed on the transparent substrate 11, it is preferable that the phase shift film is in the range of the exposure wavelength of 365 nm to 436 nm. The reflectivity is below 10%, and the front reflectivity of the shading film is below 10%. The photomask substrate can be used as a phase shift photomask with a higher pattern resolution effect brought by the phase shift effect. The light shielding film pattern in the phase shift mask becomes a phase shift film pattern or a phase shift film pattern and a light shielding film pattern.

關於上述半透光膜及相位偏移膜,對作為構成遮光膜12之材料之鉻系材料具有蝕刻選擇性之材料較為合適。作為此種材料,可使用含有鉬(Mo)、鋯(Zr)、鈦(Ti)、鉭(Ta)及矽(Si)之金屬矽化物系材料,進而包含氧、氮、碳、或氟之至少任一者之材料較為合適。例如,MoSi、ZrSi、TiSi、TaSi、MoZrSi、MoTiSi、MoTaSi等金屬矽化物、金屬矽化物之氧化物、金屬矽化物之氮化物、金屬矽化物之氮氧化物、金屬矽化物之碳氮化物、金屬矽化物之氧碳化物、金屬矽化物之碳氮氧化物較為合適。再者,該等半透光膜或相位偏移膜亦可為由作為功能膜而列舉之上述膜構成之積層膜。Regarding the above-mentioned semi-transmissive film and phase shift film, a material having etching selectivity to the chromium-based material constituting the light-shielding film 12 is suitable. As such materials, metal silicide-based materials containing molybdenum (Mo), zirconium (Zr), titanium (Ti), tantalum (Ta), and silicon (Si) can be used, and further containing oxygen, nitrogen, carbon, or fluorine At least one of the materials is more suitable. For example, MoSi, ZrSi, TiSi, TaSi, MoZrSi, MoTiSi, MoTaSi and other metal silicides, oxides of metal silicides, nitrides of metal silicides, oxynitrides of metal silicides, carbonitrides of metal silicides, Oxycarbide of metal silicide and carbonitride of metal silicide are more suitable. In addition, these semi-light transmissive films or phase shift films may also be laminated films composed of the above-mentioned films exemplified as functional films.

又,於上述實施方式中,亦可於遮光膜12上形成由與遮光膜12具有蝕刻選擇性之材料構成之蝕刻遮罩膜。Furthermore, in the above-mentioned embodiment, an etching mask film made of a material having an etching selectivity with the light-shielding film 12 may also be formed on the light-shielding film 12.

又,於上述實施方式中,亦可於透明基板11與遮光膜12之間形成由與遮光膜具有蝕刻選擇性之材料構成之蝕刻阻擋膜。上述蝕刻遮罩膜、蝕刻阻擋膜係由對作為構成遮光膜12之材料之鉻系材料具有蝕刻選擇性之材料構成。作為此種材料,可例舉含有鉬(Mo)、鋯(Zr)、鈦(Ti)、鉭(Ta)及矽(Si)之金屬矽化物系材料或Si、SiO、SiO2 、SiON、Si3 N4 等矽系材料。 [實施例]In addition, in the above-mentioned embodiment, an etching stopper film made of a material having an etching selectivity with the light shielding film may also be formed between the transparent substrate 11 and the light shielding film 12. The above-mentioned etching mask film and etching stopper film are composed of a material having an etching selectivity to a chromium-based material constituting the light-shielding film 12. Examples of such materials include metal silicide-based materials containing molybdenum (Mo), zirconium (Zr), titanium (Ti), tantalum (Ta), and silicon (Si), or Si, SiO, SiO 2 , SiON, and Si 3 N 4 and other silicon-based materials. [Example]

繼而,基於實施例對本發明進而詳細地進行說明,但本發明並不限定於該等實施例。Next, the present invention will be further described in detail based on examples, but the present invention is not limited to these examples.

<實施例1> 於本實施例中,使用直列型濺鍍裝置,並依據上述實施方式所示之順序,製造如圖1所示之於基板尺寸為1220 mm×1400 mm之透明基板上使第1低氧化鉻層、第1高氧化鉻層、遮光層、第2低氧化鉻層、及第2高氧化鉻層依序積層而具備遮光膜之光罩基底。<Example 1> In this embodiment, an in-line sputtering device is used, and the first low chromium oxide layer is produced on a transparent substrate with a substrate size of 1220 mm×1400 mm as shown in FIG. 1 according to the sequence shown in the above embodiment. , The first high chromium oxide layer, the light-shielding layer, the second low chromium oxide layer, and the second high chromium oxide layer are sequentially laminated to form a mask base with a light-shielding film.

關於第1低氧化鉻層及第2高氧化鉻層之成膜條件,以成為O相對於N之比率相對較小之第1低氧化鉻層、O相對於N之比率相對較大之第1高氧化鉻層之方式將濺鍍靶設為Cr濺鍍靶,關於反應性氣體之流量,以成為金屬模式之方式分別自1~45 sccm之範圍選擇氧系氣體之流量,自30~60 sccm之範圍選擇氮系氣體之流量,自1~15 sccm之範圍選擇烴系氣體之流量,自20~100 sccm之範圍選擇稀有氣體之流量,並且於1.0~6.0 kW範圍內設定靶施加功率。Regarding the film forming conditions of the first low chromium oxide layer and the second high chromium oxide layer, the first low chromium oxide layer with a relatively small ratio of O to N and the first low chromium oxide layer with a relatively large ratio of O to N For the method of high chromium oxide layer, the sputtering target is set as the Cr sputtering target. Regarding the flow rate of the reactive gas, select the flow rate of the oxygen-based gas from the range of 1 to 45 sccm in a metal mode, from 30 to 60 sccm The range selects the flow rate of nitrogen-based gas, the flow rate of hydrocarbon-based gas is selected from the range of 1-15 sccm, the flow rate of rare gas is selected from the range of 20-100 sccm, and the target applied power is set in the range of 1.0-6.0 kW.

關於遮光層之成膜條件,將濺鍍靶設為Cr濺鍍靶,將稀有氣體之流量設定為60~200 sccm之範圍,並於3.0~10.0 kW之範圍內設定靶施加功率。Regarding the film forming conditions of the light-shielding layer, the sputtering target is set as the Cr sputtering target, the flow rate of the rare gas is set in the range of 60-200 sccm, and the target application power is set in the range of 3.0-10.0 kW.

關於第2低氧化鉻層及第2高氧化鉻層之成膜條件,以成為O相對於N之比率相對較小之第2低氧化鉻層、O相對於N之比率相對較大之第2高氧化鉻層之方式將濺鍍靶設為Cr濺鍍靶,關於反應性氣體之流量,以成為金屬模式之方式分別自1~45 sccm之範圍選擇氧系氣體之流量,自30~60 sccm之範圍選擇氮系氣體之流量,自1~15 sccm之範圍選擇烴系氣體之流量,自20~100 sccm之範圍選擇稀有氣體之流量,並於1.0~6.0 kW之範圍內設定靶施加功率。Regarding the film formation conditions of the second low chromium oxide layer and the second high chromium oxide layer, the second low chromium oxide layer has a relatively small ratio of O to N, and the second low chromium oxide layer has a relatively large ratio of O to N. For the method of high chromium oxide layer, the sputtering target is set as the Cr sputtering target. Regarding the flow rate of the reactive gas, select the flow rate of the oxygen-based gas from the range of 1 to 45 sccm in a metal mode, from 30 to 60 sccm The range selects the flow rate of nitrogen-based gas, the flow rate of hydrocarbon-based gas is selected from the range of 1-15 sccm, the flow rate of rare gas is selected from the range of 20-100 sccm, and the target applied power is set in the range of 1.0-6.0 kW.

關於所獲得之光罩基底之遮光膜,藉由X射線光電子分光法(XPS)測定膜厚方向之組成,結果確認到遮光膜中之各層具有圖2所示之組成分佈。圖2係表示實施例1之光罩基底中之膜厚方向之組成分析結果的圖,橫軸表示膜厚,縱軸表示元素之含有率[原子%]。膜厚表示距遮光膜正面之深度[nm]。Regarding the obtained light-shielding film of the mask base, the composition in the film thickness direction was measured by X-ray photoelectron spectroscopy (XPS). As a result, it was confirmed that each layer in the light-shielding film had the composition distribution shown in FIG. 2. 2 is a graph showing the results of composition analysis in the film thickness direction in the mask substrate of Example 1. The horizontal axis represents the film thickness, and the vertical axis represents the element content [atom %]. The film thickness represents the depth [nm] from the front surface of the light-shielding film.

圖2中,於遮光膜之正面附近含有約15原子%之碳(C)之區域為正面自然氧化層。距遮光膜正面(正面自然氧化層除外)之深度約為1.3 nm至約14 nm之區域為第2高氧化鉻層,其氧(O)相對於氮(N)之比率為2.5以上。距遮光膜正面(正面自然氧化層除外)之深度約為15 nm至約43 nm之區域為第2低氧化鉻層,其氧(O)相對於氮(N)之比率未達2.5。距遮光膜正面(正面自然氧化層除外)之深度約為44 nm至約66 nm之區域為過渡層。距遮光膜正面(正面自然氧化層除外)之深度約為67 nm至約156 nm之區域為遮光層,其鉻(Cr)之含量為97原子%以上。距遮光膜正面(正面自然氧化層除外)之深度約為157 nm至約164 nm之區域為過渡層。距遮光膜正面(正面自然氧化層除外)之深度約為165 nm至約188 nm之區域為第1高氧化鉻層,其氧(O)相對於氮(N)之比率為2.5以上。距遮光膜正面(正面自然氧化層除外)之深度約為189 nm至深度195 nm之區域為第1低氧化鉻層,其氧(O)相對於氮(N)之比率未達2.5。氧(O)相對於矽(Si)之比率約為2之區域為透明基板,透明基板與上述第1低氧化鉻層之間之區域為過渡層。In Fig. 2, the area containing about 15 atomic% of carbon (C) near the front surface of the light-shielding film is the front natural oxide layer. The area from the front surface of the light-shielding film (excluding the front natural oxide layer) with a depth of about 1.3 nm to about 14 nm is the second high chromium oxide layer, and the ratio of oxygen (O) to nitrogen (N) is 2.5 or more. The area from the front side of the light-shielding film (except the natural oxide layer on the front side) with a depth of about 15 nm to about 43 nm is the second low chromium oxide layer, and the ratio of oxygen (O) to nitrogen (N) is less than 2.5. The area from the front side of the shading film (except the natural oxide layer on the front side) with a depth of about 44 nm to about 66 nm is the transition layer. The area from the front surface of the light-shielding film (except the natural oxide layer on the front side) with a depth of about 67 nm to about 156 nm is the light-shielding layer, and the content of chromium (Cr) is more than 97 atomic%. The area from the front side of the shading film (except the natural oxide layer on the front side) with a depth of about 157 nm to about 164 nm is the transition layer. The area from about 165 nm to about 188 nm deep from the front surface of the light-shielding film (except the natural oxide layer on the front side) is the first high chromium oxide layer, and the ratio of oxygen (O) to nitrogen (N) is 2.5 or more. The area from the front side of the shading film (except the natural oxide layer on the front side) with a depth of about 189 nm to a depth of 195 nm is the first low chromium oxide layer, and the ratio of oxygen (O) to nitrogen (N) is less than 2.5. The area where the ratio of oxygen (O) to silicon (Si) is about 2 is the transparent substrate, and the area between the transparent substrate and the first low chromium oxide layer is the transition layer.

如圖2所示,第1低氧化鉻層為CrCON膜,包含54.2~56.5原子%之Cr、12.0~14.2原子%之N、14.8~15.1原子%之O、2.7~4.3原子%之C。O相對於N之比率(O/N比)為1.9~2.4。As shown in Figure 2, the first low chromium oxide layer is a CrCON film, which contains 54.2-56.5 atomic% of Cr, 12.0-14.2 atomic% of N, 14.8-15.1 atomic% of O, and 2.7 to 4.3 atomic% of C. The ratio of O to N (O/N ratio) is 1.9 to 2.4.

第1高氧化鉻層為CrCON膜,包含57.1~90.7原子%之Cr、2.0~11.3原子%之N、7.3~28.3原子%之O、0~3.3原子%之C。O相對於N之比率(O/N比)為2.5~3.6。The first high chromium oxide layer is a CrCON film, which contains 57.1-90.7 atomic% of Cr, 2.0-11.3 atomic% of N, 7.3-28.3 atomic% of O, and 0-3.3 atomic% of C. The ratio of O to N (O/N ratio) is 2.5 to 3.6.

遮光層為CrO膜,包含97.4~99.1原子%之Cr、0.9~2.6原子%之O。The light-shielding layer is a CrO film, which contains 97.4-99.1 at% of Cr and 0.9-2.6 at% of O.

第2低氧化鉻層為CrCON膜,包含49.3~76.9原子%之Cr、6.2~18.9原子%之N、24.4~32.5原子%之O、2.9~5.2原子%之C。O相對於N之比率(O/N比)為1.3~2.4。The second low chromium oxide layer is a CrCON film, containing 49.3-76.9 atomic% of Cr, 6.2-18.9 atomic% of N, 24.4-32.5 atomic% of O, and 2.9-5.2 atomic% of C. The ratio of O to N (O/N ratio) is 1.3 to 2.4.

第2高氧化鉻層為CrCON膜,包含42.3~49.0原子%之Cr、8.7~12.4原子%之N、35.3~44.8原子%之O、2.2~4.2原子%之C。O相對於N之比率(O/N比)為2.9~5.2。The second high chromium oxide layer is a CrCON film, which contains 42.3 to 49.0 atomic% of Cr, 8.7 to 12.4 atomic% of N, 35.3 to 44.8 atomic% of O, and 2.2 to 4.2 atomic% of C. The ratio of O to N (O/N ratio) is 2.9 to 5.2.

(光罩基底之評價) 關於實施例1之光罩基底,藉由以下所示之方法對遮光膜之光學密度、遮光膜之正面及背面之反射率進行評價。(Evaluation of mask substrate) Regarding the photomask substrate of Example 1, the optical density of the light-shielding film and the reflectance of the front and back surfaces of the light-shielding film were evaluated by the methods shown below.

針對實施例1之光罩基底,藉由分光光度計(島津製作所股份有限公司製造之「SolidSpec-3700」)測定遮光膜之光學密度,結果於作為曝光之光之波長頻帶之g線(波長436 nm)下為5.0以上。又,藉由分光光度計(島津製作所股份有限公司製造之「SolidSpec-3700」)測定遮光膜之正面及背面之反射率。具體而言,藉由分光光度計分別測定遮光膜之第2反射抑制層側之反射率(正面反射率)與遮光膜之透明基板側之反射率(背面反射率)。其結果為獲得如圖3所示之反射率光譜。圖3表示與實施例1之光罩基底相關之正面及背面之反射率光譜,分別為橫軸表示波長[nm],縱軸表示反射率[%]。 如圖3所示,確認到實施例1之光罩基底對於範圍廣泛之波長之光可大幅降低反射率。具體而言,於波長300 nm~436 nm下,遮光膜之正面反射率為15.0%以下(12.2%(波長300 nm)、10.9 nm(波長313 nm)、8.2%(波長334 nm)、4.3%(波長365 nm)、1.8%(波長405 nm)、1.7%(波長413 nm)、2.0%(波長436 nm)),於波長365 nm~436 nm下,遮光膜之正面反射率為10.0%以下(4.3%(波長365 nm)、1.8%(波長405 nm)、1.7%(波長413 nm)、2.0%(波長436 nm))。又,遮光膜之背面反射率於波長350 nm~436 nm及波長365 nm~436 nm下為7.5%以下(7.4%(波長300 nm)、6.2%(波長313 nm)、3.9%(波長334 nm)、1.7%(波長365 nm)、0.9%(波長405 nm)、2.1%(波長436 nm))。 又,曝光波長300 nm~436 nm之範圍內之遮光膜之正面反射率之依存性為10.6%,背面反射率之依存性為6.6%。又,曝光波長365 nm~436 nm之範圍內之遮光膜之正面反射率之依存性為2.7%,背面反射率之依存性為1.3%而良好。 於跨及波長300 nm~500 nm之波長頻帶中,與正面反射率及背面反射率之最小值(峰谷)對應之波長(峰谷波長)係正面反射率為436 nm,背面反射率為415.5 nm。For the mask substrate of Example 1, the optical density of the light-shielding film was measured by a spectrophotometer ("SolidSpec-3700" manufactured by Shimadzu Corporation). The result was that the g-line (wavelength 436 nm) is 5.0 or more. In addition, the reflectance of the front and back of the light-shielding film was measured by a spectrophotometer ("SolidSpec-3700" manufactured by Shimadzu Corporation). Specifically, the reflectance on the second reflection suppression layer side of the light-shielding film (front reflectance) and the reflectance on the transparent substrate side of the light-shielding film (back reflectance) were measured by a spectrophotometer. As a result, the reflectance spectrum shown in Figure 3 is obtained. Fig. 3 shows the reflectance spectra of the front and back of the photomask substrate of Example 1. The horizontal axis represents the wavelength [nm], and the vertical axis represents the reflectance [%]. As shown in FIG. 3, it was confirmed that the photomask substrate of Example 1 can greatly reduce the reflectance for light of a wide range of wavelengths. Specifically, at a wavelength of 300 nm to 436 nm, the front reflectance of the shading film is below 15.0% (12.2% (wavelength 300 nm), 10.9 nm (wavelength 313 nm), 8.2% (wavelength 334 nm), 4.3% (Wavelength 365 nm), 1.8% (wavelength 405 nm), 1.7% (wavelength 413 nm), 2.0% (wavelength 436 nm)), under the wavelength of 365 nm ~ 436 nm, the front reflectivity of the shading film is below 10.0% (4.3% (wavelength 365 nm), 1.8% (wavelength 405 nm), 1.7% (wavelength 413 nm), 2.0% (wavelength 436 nm)). In addition, the back surface reflectance of the light-shielding film is 7.5% or less (7.4% (wavelength 300 nm), 6.2% (wavelength 313 nm), 3.9% (wavelength 334 nm) at wavelengths of 350 nm to 436 nm and wavelengths of 365 nm to 436 nm ), 1.7% (wavelength 365 nm), 0.9% (wavelength 405 nm), 2.1% (wavelength 436 nm)). In addition, the dependence of the front reflectance of the light-shielding film within the exposure wavelength range of 300 nm to 436 nm is 10.6%, and the dependence of the back reflectance is 6.6%. In addition, the dependence of the front reflectance of the light-shielding film in the exposure wavelength range of 365 nm to 436 nm is 2.7%, and the dependence of the back reflectance is 1.3%, which is good. In the wavelength band spanning from 300 nm to 500 nm, the wavelength (peak-valley wavelength) corresponding to the minimum value (peak-valley) of the front reflectance and the back reflectance is the front reflectance of 436 nm, and the back reflectance of 415.5 nm.

(遮光膜圖案之評價) 使用實施例1之光罩基底於透明基板上形成遮光膜圖案。具體而言,於透明基板上之遮光膜上形成酚醛清漆系正型抗蝕膜後,進行雷射描繪(波長413 nm)、顯影處理而形成抗蝕圖案。其後,將抗蝕圖案作為遮罩並藉由鉻蝕刻液進行濕式蝕刻,於透明基板上形成遮光膜圖案。遮光膜圖案之評價係形成2.5 μm之線與間隙圖案後藉由掃描電子顯微鏡(SEM)觀察遮光膜圖案之剖面形狀而進行。其結果為,確認到遮光膜圖案之側面與透明基板所成之角為77°。根據該情況確認可將遮光膜圖案之剖面形狀形成為接近垂直之狀態。(Evaluation of shading film pattern) The mask base of Example 1 is used to form a light-shielding film pattern on a transparent substrate. Specifically, after forming a novolak-based positive resist film on a light-shielding film on a transparent substrate, laser drawing (wavelength 413 nm) and development are performed to form a resist pattern. After that, the resist pattern is used as a mask and wet etching is performed with a chromium etching solution to form a light-shielding film pattern on the transparent substrate. The evaluation of the light-shielding film pattern was performed by observing the cross-sectional shape of the light-shielding film pattern by a scanning electron microscope (SEM) after forming a 2.5 μm line and gap pattern. As a result, it was confirmed that the angle formed by the side surface of the light-shielding film pattern and the transparent substrate was 77°. Based on this situation, it was confirmed that the cross-sectional shape of the light-shielding film pattern can be formed in a nearly vertical state.

(反射率之面內均勻性) 測定所獲得之光罩基底之遮光膜之正面反射率之面內均勻性。基於使用反射率計對將基板之周緣部50 mm除外之基板面內之11×11=121點進行測定所得之正面反射率之評價結果,算出正面反射率之面內均勻性,結果為2.0%(範圍)。又,背面反射率如上所述係算出使用虛設基板之遮光膜之背面反射率之面內均勻性,結果為3.5%(範圍)。(In-plane uniformity of reflectance) The in-plane uniformity of the front reflectance of the light-shielding film of the obtained mask substrate was measured. The in-plane uniformity of the front reflectance was calculated based on the evaluation result of the front reflectance measured at 11×11=121 points in the substrate surface excluding the 50 mm periphery of the substrate with a reflectance meter, and the result was 2.0% (Scope). In addition, the back surface reflectance was calculated as described above for the in-plane uniformity of the back surface reflectance of the light-shielding film using the dummy substrate, and the result was 3.5% (range).

如以上實施例1,關於光罩基底之遮光膜,自透明基板側起使第1反射抑制層、遮光層及第2反射抑制層積層並以成為特定組成之方式構成各層,藉此可將藉由濕式蝕刻圖案化時之遮光膜圖案之剖面形狀形成為垂直。又,確認到可藉由將第1反射抑制層、及第2反射抑制層分別自透明基板側起設為低氧化鉻層與高氧化鉻層之積層構造而減少缺陷,進而以成為特定組成之方式構成各層,故遮光膜之正面及背面之反射率之面內均勻性較高。As in Example 1 above, with regard to the light-shielding film of the mask base, the first reflection-inhibiting layer, the light-shielding layer, and the second reflection-inhibiting layer are laminated from the transparent substrate side, and each layer is formed into a specific composition. When patterned by wet etching, the cross-sectional shape of the light-shielding film pattern is formed to be vertical. In addition, it was confirmed that the first reflection suppression layer and the second reflection suppression layer were formed into a laminated structure of a low chromium oxide layer and a high chromium oxide layer from the transparent substrate side, respectively, so that defects could be reduced, and a specific composition could be obtained. Each layer is constructed by the method, so the in-plane uniformity of the reflectivity of the front and back of the light-shielding film is relatively high.

(光罩之製作) 繼而,使用實施例1之光罩基底製作光罩。 首先,於光罩基底之遮光膜上形成酚醛清漆系正型抗蝕劑。接下來,使用雷射描繪裝置於該抗蝕膜描繪TFT(thin-film transistor,薄膜電晶體)面板用之電路圖案之圖案,進而藉由顯影、清洗形成特定之抗蝕圖案(上述電路圖案之最小線寬為0.75 μm)。 其後,將抗蝕圖案作為遮罩,使用鉻蝕刻液並利用濕式蝕刻對遮光膜進行圖案化,最後藉由抗蝕劑剝離液將抗蝕圖案剝離,獲得於透明基板上形成有遮光膜圖案(遮光膜圖案)之光罩。該光罩之形成於透明基板上之遮光膜圖案(遮光膜圖案)之開口率、即形成有遮光膜圖案之光罩整個面之區域中所占之未形成遮光膜圖案之透明基板之露出比率為45%。 藉由掃描電子顯微鏡(SEM)對該光罩之遮光膜圖案進行觀察,結果遮光膜圖案之剖面形狀為77°而良好。藉由Seiko Instruments Nano Technologies股份有限公司製造之「SIR8000」測定該光罩之遮光膜圖案之CD均勻性。CD均勻性之測定係針對將基板之周緣區域除外之1100 mm×1300 mm之區域,於11×11個地點進行測定。其結果為,CD均勻性未達60 nm,而所獲得之光罩之CD均勻性良好。(Making of Mask) Then, the mask substrate of Example 1 was used to make a mask. First, a novolak-based positive resist is formed on the light-shielding film of the mask substrate. Next, a laser drawing device is used to draw a pattern of a circuit pattern for a TFT (thin-film transistor) panel on the resist film, and then a specific resist pattern (the above-mentioned circuit pattern is formed by developing and cleaning). The minimum line width is 0.75 μm). After that, the resist pattern is used as a mask, and the light shielding film is patterned by wet etching using a chromium etching solution, and finally the resist pattern is peeled off with a resist stripping solution to obtain a light shielding film formed on a transparent substrate Pattern (shading film pattern) mask. The aperture ratio of the light-shielding film pattern (light-shielding film pattern) formed on the transparent substrate of the mask, that is, the exposure ratio of the transparent substrate without the light-shielding film pattern in the area of the entire surface of the mask with the light-shielding film pattern formed Is 45%. The light-shielding film pattern of the mask was observed by a scanning electron microscope (SEM), and as a result, the cross-sectional shape of the light-shielding film pattern was 77°, which was good. The CD uniformity of the light-shielding film pattern of the mask was measured by "SIR8000" manufactured by Seiko Instruments Nano Technologies Co., Ltd. The CD uniformity is measured at 11×11 locations in an area of 1100 mm×1300 mm excluding the peripheral area of the substrate. As a result, the CD uniformity is less than 60 nm, and the CD uniformity of the obtained photomask is good.

(LCD面板之製作) 將該實施例1中所製作之光罩設置於曝光裝置之遮罩台,對於顯示裝置(TFT)用之基板上形成有抗蝕膜之被轉印體進行圖案曝光而製作TFT陣列。作為曝光之光,使用包含波長365 nm之i線、波長405 nm之h線、及波長436 nm之g線之複合光。 將所製作之TFT陣列與彩色濾光片、偏振光板、背光裝置進行組合而製作TFT-LCD面板。其結果為,獲得不存在顯示不均之TFT-LCD面板。認為其原因在於使用光罩進行圖案曝光時,可抑制光於正面及背面之反射而減少反射光之合計光量,又,可提高反射率之面內均勻性。(Production of LCD panel) The photomask produced in this Example 1 was set on the mask stage of the exposure device, and the transferred body on which the resist film was formed on the substrate for the display device (TFT) was subjected to pattern exposure to produce a TFT array. As the exposure light, composite light including i-line with a wavelength of 365 nm, h-line with a wavelength of 405 nm, and g-line with a wavelength of 436 nm is used. The fabricated TFT array is combined with color filters, polarizing plates, and backlight devices to fabricate TFT-LCD panels. As a result, a TFT-LCD panel without display unevenness was obtained. It is believed that the reason is that when a photomask is used for pattern exposure, the reflection of light on the front and back surfaces can be suppressed to reduce the total amount of reflected light, and the in-plane uniformity of reflectance can be improved.

(參考例1) 於參考例1中,將第1反射抑制層設為單層氧化鉻層,將第2反射抑制層自透明基板側起設為高氧化鉻層與低氧化鉻層之積層構造,將遮光層設為CrON,除此以外,以與實施例1相同之方式製作光罩基底。(Reference example 1) In Reference Example 1, the first reflection suppression layer is a single-layer chromium oxide layer, the second reflection suppression layer is a multilayer structure of a high chromium oxide layer and a low chromium oxide layer from the transparent substrate side, and the light-shielding layer is provided Except for CrON, the mask substrate was produced in the same manner as in Example 1.

關於第1反射抑制層之成膜條件,將濺鍍靶設為Cr濺鍍靶,關於反應性氣體之流量,以成為金屬模式之方式分別自5~45 sccm之範圍選擇氧系氣體之流量,自30~60 sccm之範圍選擇氮系氣體之流量,自60~150 sccm之範圍選擇稀有氣體之流量,並且於2.0~6.0 kW之範圍內設定靶施加功率。Regarding the film formation conditions of the first reflection suppression layer, the sputtering target is set as the Cr sputtering target, and the flow rate of the reactive gas is selected from the range of 5 to 45 sccm so that the flow rate of the reactive gas becomes the metal mode. Select the flow rate of nitrogen-based gas from the range of 30-60 sccm, select the flow rate of the rare gas from the range of 60-150 sccm, and set the target applied power in the range of 2.0-6.0 kW.

關於遮光層之成膜條件,將濺鍍靶設為Cr濺鍍靶,關於反應性氣體之流量,以成為金屬模式之方式分別自1~60 sccm之範圍選擇氮系氣體之流量,自60~200 sccm之範圍選擇稀有氣體之流量,並且於3.0~7.0 kW之範圍內設定靶施加功率。Regarding the film forming conditions of the light-shielding layer, the sputtering target was set as the Cr sputtering target. Regarding the flow rate of the reactive gas, the flow rate of the nitrogen-based gas was selected from the range of 1 to 60 sccm so as to become the metal mode, from 60 to 60 sccm. Select the flow rate of the rare gas in the range of 200 sccm, and set the target applied power in the range of 3.0 to 7.0 kW.

關於第2反射抑制層之成膜條件,將濺鍍靶設為Cr濺鍍靶,關於反應性氣體之流量,以成為金屬模式之方式分別自8~45 sccm之範圍選擇氧系氣體之流量,自30~60 sccm之範圍選擇氮系氣體之流量,自60~150 sccm之範圍選擇稀有氣體之流量,並於2.0~6.0 kW之範圍內設定靶施加功率。Regarding the film formation conditions of the second reflection suppression layer, the sputtering target is set as the Cr sputtering target, and the flow rate of the reactive gas is selected from the range of 8 to 45 sccm so that the flow rate of the reactive gas becomes the metal mode. Select the flow rate of nitrogen-based gas from the range of 30-60 sccm, select the flow rate of the rare gas from the range of 60-150 sccm, and set the target applied power in the range of 2.0-6.0 kW.

針對所獲得之光罩基底之遮光膜,與實施例1同樣地,藉由XPS測定膜厚方向之組成,結果確認到遮光膜中之各層具有圖4所示之組成分佈。圖4係表示參考例1之光罩基底中之膜厚方向之組成分析結果的圖,橫軸表示膜厚,縱軸表示元素之含有率[原子%]。膜厚表示距遮光膜正面之深度[nm]。Regarding the obtained light-shielding film of the mask base, the composition in the film thickness direction was measured by XPS in the same manner as in Example 1. As a result, it was confirmed that each layer in the light-shielding film had the composition distribution shown in FIG. 4. 4 is a graph showing the result of composition analysis in the film thickness direction in the mask substrate of Reference Example 1. The horizontal axis represents the film thickness, and the vertical axis represents the element content [atom %]. The film thickness represents the depth [nm] from the front surface of the light-shielding film.

於圖4中,於遮光膜之正面附近包含約21原子%之碳(C)之區域為正面自然氧化層。氧(O)相對於氮(N)之比率未達2.5之正面自然氧化層除外之距遮光膜正面深度約為5 nm至深度約為15 nm之區域為低氧化鉻層。氧(O)相對於氮(N)之比率為2.5以上之正面自然氧化層除外之距遮光膜正面深度約為16 nm至深度約為34 nm之區域為高氧化鉻層。正面自然氧化層除外之距遮光膜正面深度約為35 nm至深度約為89 nm之區域為過渡層。正面自然氧化層除外之距遮光膜正面深度約為90 nm至約208 nm之區域為遮光層。正面自然氧化層除外之距遮光膜正面深度約為209 nm至深度約為227 nm之區域為過渡層。正面自然氧化層除外之距遮光膜正面深度約為228 nm至深度約為251 nm之區域為第1反射抑制層。氧(O)相對於矽(Si)之比率約成為2之區域為透明基板,透明基板與上述第1反射抑制層之間之區域為過渡層。In FIG. 4, the area containing about 21 atomic% of carbon (C) near the front surface of the light-shielding film is the front natural oxide layer. Except for the front side natural oxide layer where the ratio of oxygen (O) to nitrogen (N) is less than 2.5, the area with a depth of about 5 nm to a depth of about 15 nm from the front of the shading film is a low chromium oxide layer. Except for the natural oxide layer on the front surface where the ratio of oxygen (O) to nitrogen (N) is 2.5 or more, the high chromium oxide layer is the area with a depth of about 16 nm to a depth of about 34 nm from the front surface of the light-shielding film. Except for the natural oxide layer on the front side, the region from the depth of about 35 nm to the depth of about 89 nm from the front surface of the shading film is the transition layer. The area with a depth of about 90 nm to about 208 nm from the front surface of the light-shielding film except the natural oxide layer on the front side is the light-shielding layer. Except for the natural oxide layer on the front side, the region from the depth of about 209 nm to the depth of about 227 nm from the front side of the shading film is the transition layer. Except for the natural oxide layer on the front side, the area from the depth of about 228 nm to the depth of about 251 nm from the front surface of the shading film is the first reflection suppression layer. The area where the ratio of oxygen (O) to silicon (Si) is approximately 2 is the transparent substrate, and the area between the transparent substrate and the first reflection suppression layer is the transition layer.

如圖4所示,第1反射抑制層為CrCON膜,包含51.4~57原子%之Cr、13.5~18.2原子%之N、22.6~31.6原子%之O、2.8~4.8原子%之C。遮光層為CrON膜,包含85.4~91.9原子%之Cr、7.4~9.3原子%之N、0.5~6.0原子%之O。第2反射抑制層由高氧化鉻層與低氧化鉻層構成。高氧化鉻層為CrCON膜,包含49.0~50.6原子%之Cr、9.1~13.0原子%之N、33.7~39.4原子%之O、2.2~2.9原子%之C。低氧化鉻層為CrCON膜,包含50.0~51.1原子%之Cr、13.5~14.1原子%之N、31.8~33.4原子%之O、2.5~3.5原子%之C。As shown in FIG. 4, the first reflection suppression layer is a CrCON film, which contains 51.4 to 57 atomic% of Cr, 13.5-18.2 atomic% of N, 22.6 to 31.6 atomic% of O, and 2.8 to 4.8 atomic% of C. The light-shielding layer is a CrON film, which contains 85.4-91.9 atomic% of Cr, 7.4-9.3 atomic% of N, and 0.5-6.0 atomic% of O. The second reflection suppression layer is composed of a high chromium oxide layer and a low chromium oxide layer. The high chromium oxide layer is a CrCON film, containing 49.0-50.6 atomic% of Cr, 9.1-13.0 atomic% of N, 33.7-39.4 atomic% of O, and 2.2-2.9 atomic% of C. The low chromium oxide layer is a CrCON film, containing 50.0-51.1 atomic% of Cr, 13.5-14.1 atomic% of N, 31.8-33.4 atomic% of O, and 2.5 to 3.5 atomic% of C.

(光罩基底之評價) 關於參考例1之光罩基底,與實施例1同樣地測定遮光膜之光學密度,結果於作為曝光之光之波長區域之g線(波長436 nm)下為5.0以上。又,藉由分光光度計測定遮光膜之正面及背面之反射率,結果獲得如圖5所示之反射率光譜。圖5表示與比較例1之光罩基底相關之正面及背面之反射率光譜,分別為橫軸表示波長[nm],縱軸表示反射率[%]。如圖5所示,確認到參考例1之光罩基底與實施例1同樣地,能夠對範圍廣泛之波長之光大幅降低反射率。具體而言,於波長300 nm~436 nm下,遮光膜之正面反射率為15.0%以下(15.0%(波長300 nm)、13.3%(波長313 nm)、7.7%(波長365 nm)、1.8%(波長405 nm)、1.1%(波長413 nm)、0.3%(波長436 nm)),於波長365 nm~436 nm下,遮光膜之正面反射率為10.0%以下(7.7%(波長365 nm)、1.8%(波長405 nm)、1.1%(波長413 nm)、0.3%(波長436 nm))。又,確認到於波長300 nm~436 nm下,遮光膜之背面反射率為15.0%以下(12.2%(波長300 nm)、10.4%(波長313 nm)、6.2%(波長365 nm)、4.7%(波長405 nm)、4.8%(波長436 nm)),於波長365 nm~436 nm下,遮光膜之背面反射率為7.5%以下(6.2%(波長365 nm)、4.7%(波長405 nm)、4.8%(波長436 nm))。於波長350 nm~436 nm下,可將遮光膜之正面及背面之反射率降低至15%以下,或於波長365 nm~436 nm下,可將遮光膜之正面及背面之反射率降低至10%以下,尤其是關於針對波長436 nm之光之反射率,可使正面反射率為0.3%,使背面反射率為4.8%。(Evaluation of mask substrate) Regarding the mask substrate of Reference Example 1, the optical density of the light-shielding film was measured in the same manner as in Example 1. As a result, the g-line (wavelength: 436 nm), which is the wavelength region of the exposure light, was 5.0 or more. In addition, the reflectance of the front and back of the light-shielding film was measured by a spectrophotometer, and as a result, the reflectance spectrum shown in FIG. 5 was obtained. Figure 5 shows the reflectance spectra of the front and back of the photomask substrate of Comparative Example 1. The horizontal axis represents the wavelength [nm], and the vertical axis represents the reflectance [%]. As shown in FIG. 5, it was confirmed that the mask substrate of Reference Example 1 can greatly reduce the reflectance of light of a wide range of wavelengths, similarly to Example 1. Specifically, at a wavelength of 300 nm to 436 nm, the front reflectance of the shading film is 15.0% or less (15.0% (wavelength 300 nm), 13.3% (wavelength 313 nm), 7.7% (wavelength 365 nm), 1.8% (Wavelength 405 nm), 1.1% (wavelength 413 nm), 0.3% (wavelength 436 nm)), at a wavelength of 365 nm to 436 nm, the front reflectance of the shading film is below 10.0% (7.7% (wavelength 365 nm) , 1.8% (wavelength 405 nm), 1.1% (wavelength 413 nm), 0.3% (wavelength 436 nm)). In addition, it was confirmed that the back surface reflectance of the light-shielding film is 15.0% or less (12.2% (wavelength 300 nm), 10.4% (wavelength 313 nm), 6.2% (wavelength 365 nm), 4.7% at a wavelength of 300 nm to 436 nm (Wavelength 405 nm), 4.8% (wavelength 436 nm)), at a wavelength of 365 nm to 436 nm, the back reflectance of the shading film is below 7.5% (6.2% (wavelength 365 nm), 4.7% (wavelength 405 nm) , 4.8% (wavelength 436 nm)). At a wavelength of 350 nm to 436 nm, the reflectivity of the front and back of the shading film can be reduced to less than 15%, or at a wavelength of 365 nm to 436 nm, the reflectivity of the front and back of the shading film can be reduced to 10 % Or less, especially for the reflectance of light with a wavelength of 436 nm, the front reflectance can be 0.3%, and the back reflectance can be 4.8%.

對所獲得之光罩基底之遮光膜之正面反射率之面內均勻性進行測定。使用反射率計,對基板之周緣部50 mm除外之基板面內之11×11=121點進行測定而獲得正面反射率之評價結果,基於該評價結果算出正面反射率之面內均勻性,結果為3.9%(範圍)。又,背面反射率如上所述,算出使用虛設基板之遮光膜之背面反射率之面內均勻性,結果超過5.0%(範圍),目視下確認到反射率之不均。The in-plane uniformity of the front reflectance of the light-shielding film of the obtained mask base was measured. Using a reflectance meter, measure 11×11=121 points in the surface of the substrate except 50 mm of the peripheral edge of the substrate to obtain the evaluation result of the front reflectance, and calculate the in-plane uniformity of the front reflectance based on the evaluation result. 3.9% (range). In addition, the back surface reflectance was calculated as described above, and the in-plane uniformity of the back surface reflectance of the light-shielding film using the dummy substrate was calculated. As a result, it exceeded 5.0% (range), and the unevenness of the reflectance was visually confirmed.

(遮光膜圖案之評價) 針對參考例之光罩基底,與實施例1同樣地形成遮光膜圖案並進行評價。利用SEM對遮光膜圖案進行觀察,結果確認到遮光膜圖案之剖面形狀自垂直不斷傾斜為錐狀。測定遮光膜圖案之側面與透明基板所成之角,結果確認為54°。(Evaluation of shading film pattern) Regarding the mask substrate of the reference example, the light-shielding film pattern was formed and evaluated in the same manner as in Example 1. The light-shielding film pattern was observed by SEM, and as a result, it was confirmed that the cross-sectional shape of the light-shielding film pattern was continuously inclined from vertical to a tapered shape. The angle formed by the side surface of the light-shielding film pattern and the transparent substrate was measured, and the result was confirmed to be 54°.

繼而,使用參考例之光罩基底,與實施例1同樣地製作光罩。測定所獲得之光罩之遮光膜圖案之CD均勻性,結果較差,為100 nm。如上所述,參考例之光罩基底雖可降低正面及背面之反射率,但未能形成高精度之遮罩圖案。Then, using the mask base of the reference example, a mask was produced in the same manner as in Example 1. The CD uniformity of the light-shielding film pattern of the obtained mask was measured, and the result was poor, which was 100 nm. As mentioned above, although the mask substrate of the reference example can reduce the reflectivity of the front and back surfaces, it fails to form a high-precision mask pattern.

1:光罩基底 11:透明基板 12:遮光膜 13:第1反射抑制層 13a:第1低氧化鉻層 13b:第1高氧化鉻層 14:遮光層 15:第2反射抑制層 15a:第2低氧化鉻層 15b:第2高氧化鉻層1: Mask base 11: Transparent substrate 12: Shading film 13: The first reflection suppression layer 13a: The first low chromium oxide layer 13b: The first high chromium oxide layer 14: shading layer 15: The second reflection suppression layer 15a: The second low chromium oxide layer 15b: The second high chromium oxide layer

圖1係表示本發明之一實施方式之光罩基底之概略構成之剖視圖。 圖2係表示實施例1之光罩基底中之膜厚方向之組成分析結果的圖。 圖3係表示實施例1之光罩基底之正面及背面之反射率光譜的圖。 圖4係表示參考例1之光罩基底中之膜厚方向之組成分析結果的圖。 圖5係表示參考例1之光罩基底之正面及背面之反射率光譜的圖。FIG. 1 is a cross-sectional view showing a schematic configuration of a photomask substrate according to an embodiment of the present invention. FIG. 2 is a diagram showing the result of composition analysis in the film thickness direction in the mask substrate of Example 1. FIG. 3 is a graph showing the reflectance spectra of the front and back of the photomask substrate of Example 1. FIG. 4 is a diagram showing the result of composition analysis in the film thickness direction in the mask substrate of Reference Example 1. FIG. FIG. 5 is a graph showing the reflectance spectra of the front and back surfaces of the photomask substrate of Reference Example 1. FIG.

1:光罩基底 1: Mask base

11:透明基板 11: Transparent substrate

12:遮光膜 12: Shading film

13:第1反射抑制層 13: The first reflection suppression layer

13a:第1低氧化鉻層 13a: The first low chromium oxide layer

13b:第1高氧化鉻層 13b: The first high chromium oxide layer

14:遮光層 14: shading layer

15:第2反射抑制層 15: The second reflection suppression layer

15a:第2低氧化鉻層 15a: The second low chromium oxide layer

15b:第2高氧化鉻層 15b: The second high chromium oxide layer

Claims (16)

一種光罩基底,其特徵在於:其係製作顯示裝置製造用之光罩時所使用者,且具有: 透明基板,其包含對曝光之光實質上透明之材料;及 遮光膜,其設置於上述透明基板上,且包含對上述曝光之光實質上不透明之材料; 上述遮光膜自上述透明基板側起具備第1反射抑制層、遮光層及第2反射抑制層, 上述第1反射抑制層自上述透明基板側起依序具備:第1低氧化鉻層,其含有鉻、氧及氮,且氧相對於氮之比率相對較少;及第1高氧化鉻層,其含有鉻、氧及氮,且氧相對於氮之比率相對較多; 上述第2反射抑制層自上述透明基板側起依序具備:第2低氧化鉻層,其含有鉻、氧及氮,且氧相對於氮之比率相對較少;及第2高氧化鉻層,其含有鉻、氧及氮,且氧相對於氮之比率相對較多; 以上述遮光膜之正面及背面對上述曝光之光之曝光波長300 nm~436 nm之反射率分別為15%以下且光學密度成為3.0以上之方式設定至少上述第1反射抑制層、上述遮光層、及上述第2反射抑制層之組成、及膜厚。A photomask substrate, which is characterized in that it is used when manufacturing the photomask for display device manufacturing, and has: A transparent substrate, which includes a material that is substantially transparent to exposed light; and A light-shielding film, which is disposed on the above-mentioned transparent substrate and includes a material that is substantially opaque to the above-mentioned exposed light; The light-shielding film includes a first reflection-inhibiting layer, a light-shielding layer, and a second reflection-inhibiting layer from the transparent substrate side, and The first reflection suppression layer includes in order from the transparent substrate side: a first low chromium oxide layer containing chromium, oxygen, and nitrogen, and the ratio of oxygen to nitrogen is relatively small; and a first high chromium oxide layer, It contains chromium, oxygen and nitrogen, and the ratio of oxygen to nitrogen is relatively high; The second reflection suppression layer includes in order from the transparent substrate side: a second low chromium oxide layer containing chromium, oxygen, and nitrogen, and the ratio of oxygen to nitrogen is relatively small; and a second high chromium oxide layer, It contains chromium, oxygen and nitrogen, and the ratio of oxygen to nitrogen is relatively high; At least the first reflection suppression layer, the light-shielding layer, the light-shielding layer, the light-shielding layer, the light-shielding layer, And the composition and film thickness of the above-mentioned second reflection suppression layer. 如請求項1之光罩基底,其中上述遮光層係由鉻之含有率為97原子%以上且100原子%以下之鉻系材料形成。The photomask substrate of claim 1, wherein the light-shielding layer is formed of a chromium-based material with a chromium content of 97 atomic% or more and 100 atomic% or less. 如請求項1或2之光罩基底,其中上述第2高氧化鉻層中之氧相對於氮之比率為2.5以上且10以下。The photomask substrate of claim 1 or 2, wherein the ratio of oxygen to nitrogen in the second high chromium oxide layer is 2.5 or more and 10 or less. 如請求項1或2之光罩基底,其中上述第1高氧化鉻層中之氧相對於氮之比率為2.5以上且10以下。The photomask substrate of claim 1 or 2, wherein the ratio of oxygen to nitrogen in the first high chromium oxide layer is 2.5 or more and 10 or less. 如請求項1或2之光罩基底,其中上述第1反射抑制層中包含碳。The photomask substrate of claim 1 or 2, wherein the first reflection suppression layer contains carbon. 如請求項1或2之光罩基底,其中上述第2反射抑制層中包含碳。The photomask substrate of claim 1 or 2, wherein the second reflection suppression layer contains carbon. 如請求項1或2之光罩基底,其中上述第1反射抑制層之鉻之含有率為25原子%以上且75原子%以下,氧之含有率為15原子%以上且45原子%以下,氮之含有率為2原子%以上且30原子%以下, 上述第2反射抑制層之鉻之含有率為25原子%以上且75原子%以下,氧之含有率為15原子%以上且60原子%以下,氮之含有率為2原子%以上且30原子%以下。For the photomask substrate of claim 1 or 2, wherein the chromium content of the first reflection suppression layer is 25 at% or more and 75 at% or less, the oxygen content is 15 at% or more and 45 at% or less, and nitrogen The content rate is 2 atomic% or more and 30 atomic% or less, The chromium content of the second reflection suppression layer is 25 atomic% or more and 75 atomic% or less, the oxygen content is 15 atomic% or more and 60 atomic% or less, and the nitrogen content is 2 atomic% or more and 30 atomic% the following. 如請求項1或2之光罩基底,其中上述第1反射抑制層及上述第2反射抑制層分別具有氧及氮中之至少任一元素之含有率沿著膜厚方向連續地或者階段性地組成變化之區域。The mask substrate of claim 1 or 2, wherein the first reflection suppressing layer and the second reflection suppressing layer respectively have a content ratio of at least any element of oxygen and nitrogen continuously or stepwise along the film thickness direction The area of composition change. 如請求項1或2之光罩基底,其於上述透明基板與上述第1反射抑制層之間、上述第1反射抑制層與上述遮光層之間、及上述遮光層與上述第2反射抑制層之間具有構成上述第1反射抑制層、上述遮光層及上述第2反射抑制層之元素連續地組成梯度變化之梯度組成區域。The photomask base of claim 1 or 2, which is between the transparent substrate and the first reflection suppressing layer, between the first reflection suppressing layer and the light shielding layer, and between the light shielding layer and the second reflection suppressing layer There is a gradient composition region in which the elements constituting the first reflection suppression layer, the light shielding layer, and the second reflection suppression layer continuously constitute a gradient change. 如請求項1或2之光罩基底,其中上述遮光膜之正面對上述曝光之光之曝光波長之反射率之面內均勻性為3%以下。The mask substrate of claim 1 or 2, wherein the in-plane uniformity of the reflectance of the front surface of the light-shielding film to the exposure wavelength of the light to be exposed is 3% or less. 如請求項1或2之光罩基底,其於上述透明基板與上述遮光膜之間進而具備:半透光膜,其具有較上述遮光膜之光學密度低之光學密度。According to claim 1 or 2, the photomask base further includes between the transparent substrate and the light-shielding film: a semi-transparent film having an optical density lower than that of the light-shielding film. 如請求項1或2之光罩基底,其於上述透明基板與上述遮光膜之間進而具備相位偏移膜。The photomask base of claim 1 or 2 further includes a phase shift film between the transparent substrate and the light shielding film. 一種光罩之製造方法,其特徵在於具有如下步驟: 準備如請求項1至12中任一項之上述光罩基底;及 於上述遮光膜上形成抗蝕膜,將由上述抗蝕膜形成之抗蝕圖案作為遮罩對上述遮光膜進行蝕刻而於上述透明基板上形成遮光膜圖案。A method for manufacturing a photomask is characterized by the following steps: Prepare the above-mentioned mask substrate as in any one of Claims 1 to 12; and A resist film is formed on the light-shielding film, and the light-shielding film is etched using the resist pattern formed of the resist film as a mask to form a light-shielding film pattern on the transparent substrate. 一種光罩之製造方法,其特徵在於具有如下步驟: 準備如請求項1至12中任一項之上述光罩基底; 於上述遮光膜上形成抗蝕膜,將由上述抗蝕膜形成之抗蝕圖案作為遮罩對上述遮光膜進行蝕刻而於上述透明基板上形成遮光膜圖案;及 將上述遮光膜圖案作為遮罩對上述半透光膜進行蝕刻而於上述透明基板上形成半透光膜圖案。A method for manufacturing a photomask is characterized by the following steps: Prepare the above-mentioned mask substrate as in any one of claims 1 to 12; Forming a resist film on the light-shielding film, etching the light-shielding film using the resist pattern formed by the resist film as a mask to form a light-shielding film pattern on the transparent substrate; and The translucent film is etched using the light-shielding film pattern as a mask to form a translucent film pattern on the transparent substrate. 一種光罩之製造方法,其特徵在於具有如下步驟: 準備如請求項1至12中任一項之上述光罩基底; 於上述遮光膜上形成抗蝕膜,將由上述抗蝕膜形成之抗蝕圖案作為遮罩對上述遮光膜進行蝕刻而於上述透明基板上形成遮光膜圖案;及 將上述遮光膜圖案作為遮罩對上述相位偏移膜進行蝕刻而於上述透明基板上形成相位偏移膜圖案。A method for manufacturing a photomask is characterized by the following steps: Prepare the above-mentioned mask substrate as in any one of claims 1 to 12; Forming a resist film on the light-shielding film, etching the light-shielding film using the resist pattern formed by the resist film as a mask to form a light-shielding film pattern on the transparent substrate; and The phase shift film is etched using the light-shielding film pattern as a mask to form a phase shift film pattern on the transparent substrate. 一種顯示裝置之製造方法,其特徵在於具有:曝光步驟,其將藉由如請求項13至15中任一項之光罩之製造方法而獲得之光罩載置於曝光裝置之遮罩台,並將形成於上述光罩上之遮光膜圖案、上述半透光膜圖案、上述相位偏移膜圖案之至少一個遮光膜圖案曝光轉印至形成於顯示裝置基板上之抗蝕劑。A method of manufacturing a display device, characterized by having: an exposure step, which places the photomask obtained by the manufacturing method of the photomask according to any one of claims 13 to 15 on the mask stage of the exposure device, At least one of the light-shielding film pattern formed on the photomask, the semi-transparent film pattern, and the phase shift film pattern is exposed and transferred to the resist formed on the substrate of the display device.
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