TWI690767B - Mask blank, phase-shifting mask, halftone mask, method of manufacturing mask blank, and method of manufacturing phase-shifting mask - Google Patents

Abstract

The present invention provides a mask blank including: a transparent substrate; a phase-shifting layer stacked on a surface of the transparent substrate and containing Cr as a main component; an etching stopper layer stacked on the phase-shifting layer; and a light shielding layer stacked on the etching stopper layer and containing Cr as a main component. The phase-shifting layer, the etching stopper layer, and the light shielding layer are etched by the same etchant, and therefore a phase-shifting mask can be manufactured such that the edge of the light shielding pattern formed on the light shielding layer is disposed at the position retracted from the edge of the phase-shifting pattern stacked on the phase-shifting layer when seen in a plan view.

Description

Mask base, phase shift mask, half dimming mask, mask base manufacturing method, and phase shift mask manufacturing method

The present invention relates to a method for manufacturing a mask base, a phase shift mask, a half-tone mask, a mask base capable of forming a fine and high-precision exposure pattern, and a method for manufacturing a phase shift mask, in particular A technology suitable for the manufacture of flat panel displays.

A phase shift mask is used as a mask in light lithography for patterning of components such as FPD (flat panel display) and wiring, wiring, and the like. The phase-shift mask is an edge-enhanced mask in which a phase shift layer, an etch stop layer, and a light-shielding layer are sequentially provided on the surface of the transparent substrate, and can be used when the pattern distribution is made finer (for example, refer to Japanese Patent Laid-Open 2010-128003).

In addition, for FPD masks, the use of a semi-dimming mask having a semi-transmissive area reduces the number of mask sheets required to form a panel. By reducing the amount of light transmitted through the semi-transmissive area, the reduced film thickness of the photoresist after development can be controlled to a desired value.

However, in the method of the previous example described above, a phase shift mask is manufactured by forming a phase shift layer on a transparent substrate, and etching and patterning the phase shift layer The light-shielding layer is formed to cover the patterned phase shift layer, and the light-shielding layer is etched to be patterned. If the film formation and patterning are alternately performed in this way, the transfer time or processing wait time between the devices becomes longer, and the production efficiency is significantly reduced. Moreover, the light shielding layer and the phase shift layer cannot be continuously etched through a single mask having a specific opening pattern, and a mask (resist pattern) needs to be formed twice, which increases the number of manufacturing steps. Therefore, there is a problem that the phase shift mask cannot be manufactured with high mass productivity.

Furthermore, it is considered that the same etchant can be used to etch the light shielding layer and the phase shift layer at the same time, but at this time, the amount of side etching of the light shielding layer is insufficient. Therefore, there is a problem that the size of the side of the light-shielding pattern that recedes from the side of the phase shift pattern in a specific range cannot be formed in a plan view.

The present invention has been completed in view of the above circumstances, and it is intended to achieve the following objectives.

1. It is possible to reduce the number of manufacturing steps of a phase shift mask in which the side of the light shielding pattern formed on the light shielding layer is disposed further backward than the side of the phase shifting pattern deposited on the phase shifting layer in plan view.

2. The size at which the edge of the light-shielding pattern can be formed in a specific range to retreat from the edge of the phase shift pattern in plan view.

The mask base of the aspect of the present invention includes a transparent substrate, a phase shift layer mainly composed of Cr deposited on the surface of the transparent substrate, an etch stop layer deposited on the phase shift layer, and a build-up layer terminated on the etch A light-shielding layer containing Cr as a main component, and by etching the phase shift layer, the etching stop layer and the light-shielding layer with the same etchant, the light-shielding pattern formed on the side of the light-shielding layer can be manufactured A phase shift mask disposed at a position that is more backward than the side of the phase shift pattern stacked on the phase shift layer in a plan view, thereby solving the above-mentioned problem question.

In the aspect of the present invention, it is more preferable that the etching stopper layer contains at least one metal selected from the group consisting of Ni, Co, Fe, Ti, Si, Al, Nb, Mo, W, and Hf.

In the aspect of the present invention, the amount of side etching in the etching of the phase shift layer, the etching stop layer, and the light shield layer in the light shielding layer may be compared with that before the start of the etching of the phase shift layer, It is set in such a way that the point of time when the etching of the light-shielding layer becomes larger.

In addition, in the aspect of the present invention, a method may be adopted in which the side etching amount of the light-shielding layer is changed from the time before the start of the etching of the phase shift layer compared to the time before the start of the etching of the phase shift layer The setting is more than 10 times larger.

In addition, in the phase shift layer, the etching stop layer, and the light shielding layer, the light shielding layer before the start of the etching of the phase shift layer can be set to be electrochemically inert with respect to the etching stop layer, The light-shielding layer after the etching start time of the phase shift layer can be set to be electrochemically active with respect to the phase shift layer.

In addition, the above-mentioned etching stop layer can be made into a film thickness of 10 nm or more.

The manufacturing method of the mask base of the aspect of the present invention is the manufacturing method of the mask base described in any one of the above aspects, and has the phase shift layer, the etching stop layer and the layer sequentially deposited on the transparent substrate In the step of the light-shielding layer, the etching stop layer contains carbon dioxide as a film-forming gas atmosphere, and can be mainly composed of at least one metal selected from Ni, Co, Fe, Ti, Si, Al, Nb, Mo, W, and Hf Components by sputtering.

The method of manufacturing a phase shift mask of the aspect of the present invention is a method of manufacturing a phase shift mask using the mask substrate described in any of the above aspects, and may be formed on the light-shielding layer with a specific The step of masking the opening pattern, and the wet etching of the phase shift layer, the etching stop layer, and the light shielding layer using the same etchant through the formed mask Engraved steps.

In addition, in the step of simultaneously performing wet etching on the phase shift layer, the etching stop layer, and the light shielding layer, the side etching amount of the light shielding layer may be set to 4-5 of the side etching amount of the phase shift layer Times.

In addition, as the etchant described above, an etchant containing cerium diammonium nitrate is preferably used.

The phase shift mask of the aspect of the present invention can be manufactured by the manufacturing method described in any of the above aspects.

The mask base of the aspect of the present invention is provided with a transparent substrate, a halftone layer mainly composed of Cr deposited on the surface of the transparent substrate, an etch stop layer deposited on the halftone layer, and a etch stop layer deposited on the etch stop layer A light-shielding layer mainly composed of Cr, and by etching the halftone layer, the etching stop layer, and the light-shielding layer with the same etchant, the side of the light-shielding pattern formed on the light-shielding layer can be manufactured A plan view of the half dimming mask positioned further back than the edge of the half tone pattern stacked on the above half tone layer, thereby solving the above-mentioned problem.

The mask base of the aspect of the present invention may be formed on the light-shielding layer, the side etching amount of the halftone layer, the etch stop layer and the light-shielding layer during the etching is before the starting point of the etching of the halftone layer In contrast, it is set such that the time point becomes larger from the start of the etching of the light-shielding layer.

The manufacturing method of the mask base of the aspect of the present invention is the manufacturing method of the mask base described in any of the above aspects, and has the above-mentioned halftone layer, the etching stop layer and the The step of the light-shielding layer, the etching stop layer contains carbon dioxide as a film-forming gas atmosphere, and can contain at least one metal selected from Ni, Co, Fe, Ti, Si, Al, Nb, Mo, W, and Hf as a main component And the film is formed by sputtering.

The half dimming mask of the aspect of the present invention can be manufactured by the manufacturing method of the above aspect.

The mask base of the aspect of the present invention is provided with a transparent substrate and a surface laminated on the transparent substrate A phase shift layer mainly composed of Cr, an etch stop layer deposited on the above phase shift layer, and a light shielding layer mainly composed of Cr deposited on the etch stop layer, and by using the same etchant The phase shift layer, the etching stop layer and the light shielding layer are etched, and the side of the light shielding pattern formed on the light shielding layer can be manufactured to be arranged on the side of the phase shift pattern stacked on the phase shifting layer in plan view The phase shift mask of the retreated position. Thereby, the light shielding layer can be etched first, then the etching stop layer can be etched, and then the phase shift layer can be etched, and the light shielding layer can be side-etched to form the light shielding pattern and the phase deviation by one continuous etching. Shift pattern. Thereby, the resist pattern formation is not performed twice or more and the light-shielding pattern and the phase shift pattern are formed by one continuous etching, and at the same time, the etching stop layer can also remove the corresponding portion. Therefore, it is possible to provide a mask base capable of reducing the number of manufacturing steps, reducing the amount of work, shortening the manufacturing time, and reducing the cost, and a phase shift mask manufactured from the mask base.

In the aspect of the present invention, the etching stop layer is composed of at least one metal selected from Ni, Co, Fe, Ti, Si, Al, Nb, Mo, W, and Hf as a main component. By this, the etching stop layer can be etched with the same etchant as the phase shift layer and the light shielding layer mainly composed of Cr (chromium), and the light shielding layer can be etched first, then the etching stopper layer can be etched, and then The phase shift layer is etched, and the light-shielding layer is side-etched. Thereby, the light-shielding pattern and the phase shift pattern can be formed by one continuous etching.

According to an aspect of the present invention, in the light-shielding layer, the side etching amount of the phase shift layer, the etching stop layer, and the light-shielding layer during the etching may be compared with that before the start of the etching of the phase shift layer. It is set in such a way that the point of time when the etching of the light-shielding layer becomes larger. Thereby, the light shielding layer, the etch stop layer and the phase shift layer can be processed by one continuous etching, and the light shielding layer can be side-etched to be formed on the light shielding layer with a specific size The side of the light-shielding pattern is arranged in a phase shift mask that is further back than the side of the phase shift pattern stacked on the phase shift layer in a plan view.

Furthermore, in the aspect of the present invention, the side etching amount of the light-shielding layer is set to be more than 10 times greater than the etching start time of the phase shift layer from before the etching start time of the phase shift layer. In this way, the light shielding layer, the etch stop layer and the phase shift layer can be processed by one continuous etching, and the light shielding layer can be side-etched, so that the side of the light shielding pattern formed on the light shielding layer can be arranged in a stacked view in plan view. The size of the position where the side of the phase shift pattern of the phase shift layer is set back further becomes suitable for manufacturing the phase shift mask in a manner suitable for the range of the edge enhanced mask.

In addition, the light-shielding layer before the start of the etching of the phase shift layer, the etching stop layer, and the light-shielding layer is set to be electrochemically inert with respect to the etching stop layer. The light-shielding layer after the start of the etching of the phase shift layer is set to be electrochemically active relative to the phase shift layer. In this way, when the light shielding layer, the etching stop layer and the phase shift layer are processed by one continuous etching, the light shielding layer is first etched, then the etching stop layer is etched, and then the phase shift layer is etched, In addition, when etching the phase shift layer, the light shielding layer can be side-etched with a side etching amount larger than that of the phase shift layer.

In addition, the above-mentioned etching stop layer is formed to a film thickness of 10 nm or more. In this way, when the light shielding layer, the etching stop layer and the phase shift layer are processed by one continuous etching, the light shielding layer is first etched, then the etching stop layer is etched, and then the phase shift layer is etched, In addition, when the phase shift layer is etched, the light shielding layer can be side-etched with a side etching amount larger than that of the phase shift layer.

The manufacturing method of the mask base of the aspect of this invention is the mask base described in any one of the above The bottom manufacturing method includes the steps of sequentially depositing the phase shift layer, the etching stop layer and the light shielding layer on the transparent substrate. The etching stop layer contains carbon dioxide as a film forming gas atmosphere and is selected from Ni and Co. At least one metal of Fe, Ti, Si, Al, Nb, Mo, W, and Hf is a main component, and a film is formed by sputtering. Thereby, it can be set that the light-shielding layer before the etching start time of the phase shift layer is electrochemically inert with respect to the etching stop layer, and that the light-shielding layer after the etching start time of the phase shift layer is shifted relative to the phase The layer transfer is electrochemically active. In this way, when the light shielding layer, the etching stop layer and the phase shift layer are processed by one continuous etching, the light shielding layer is first etched, then the etching stop layer is etched, and then the phase shift layer is etched, In addition, when the phase shift layer is etched, the light shielding layer can be side-etched with a side etching amount larger than that of the phase shift layer.

The method for manufacturing a phase shift mask according to the aspect of the present invention is a method for manufacturing a phase shift mask using the mask substrate described in any one of the above, and has a mask having a specific opening pattern formed on the light shielding layer The step and the step of wet etching the phase shift layer, the etching stop layer and the light shielding layer simultaneously using the same etchant through the formed mask. In this way, the mask pattern can be formed at a time, the light shielding layer is etched first, then the etching stop layer is etched, and then the phase shift layer is etched, and when the phase shift layer is etched, the phase The side etching amount of the offset layer having a large side etching amount performs side etching of the light-shielding layer, so that a specific light-shielding pattern and phase shift pattern can be easily formed based on the image defined by the mask pattern.

In addition, in the step of simultaneously performing wet etching on the phase shift layer, the etching stop layer, and the light shielding layer, the amount of side etching in the light shielding layer is set to 4~ of the amount of side etching on the phase shift layer About 5 times. By this, the light shielding layer can be easily etched sideways with a large amount of side etching, and a specific light shielding pattern and phase can be formed based on the image defined by the mask pattern Bit shift pattern.

As the etchant, an etchant containing cerium diammonium nitrate was used. Thereby, the phase shift layer, the etching stop layer and the light shielding layer can be simultaneously wet-etched with the same etchant.

The phase shift mask of the aspect of the present invention can be manufactured by the manufacturing method described in any one of the above.

The mask base of the aspect of the present invention is provided with a transparent substrate, a halftone layer mainly composed of Cr deposited on the surface of the transparent substrate, an etch stop layer deposited on the halftone layer, and a etch stop layer deposited on the etch stop layer A light-shielding layer mainly composed of Cr, and by etching the halftone layer, the etching stop layer, and the light-shielding layer with the same etchant, the side of the light-shielding pattern formed on the light-shielding layer can be manufactured The half dimming mask located at a position further back than the edge of the half tone pattern stacked on the above half tone layer when viewed from above. Thereby, the light-shielding layer can be etched first, then the etching stop layer can be etched, and then the halftone layer can be etched, and the light-shielding layer can be side-etched to form the light-shielding pattern and the halftone pattern by one continuous etch . Thereby, the resist pattern formation is not performed twice or more, and the light-shielding pattern and the halftone pattern are formed by one continuous etching, and at the same time, the etching stop layer can also remove the corresponding part, so it is possible to provide a method that can reduce the number of manufacturing steps 1. A mask base that reduces the amount of work, shortens the manufacturing time, and lowers the cost, and a half-light mask manufactured by the mask base.

The mask base of the aspect of the present invention is on the light-shielding layer, and the side etching amount of the halftone layer, the etching stop layer and the light-shielding layer during the etching is compared with that before the start of the etching of the halftone layer , Set in such a way that the time point of the etching of the light-shielding layer becomes larger. Thereby, the light shielding layer, the etch stop layer and the halftone layer can be processed by one continuous etching, and the light shielding layer can be side-etched to produce the light shield formed on the light shielding layer with a specific size The side of the pattern is arranged in a half dimming mask at a position that is further back than the side of the half tone pattern formed in the above half tone layer in a plan view.

The manufacturing method of the mask base according to the aspect of the present invention is the manufacturing method of the mask base described in any one of the above, and has a method of sequentially depositing the halftone layer, the etching stop layer and the light-shielding layer on the transparent substrate Step, the above etching stop layer contains carbon dioxide as a film forming gas atmosphere, and is mainly composed of at least one metal selected from Ni, Co, Fe, Ti, Si, Al, Nb, Mo, W, and Hf by sputtering Plated into a film. In this way, it can be set that the light-shielding layer before the etching start time of the halftone layer is electrochemically inert with respect to the etching stop layer, and the light-shielding layer after the etching start time of the halftone layer is set with respect to the halftone layer It is electrochemically active, so that when the shading layer, the etching stop layer and the halftone layer are processed by one continuous etching, the shading layer is first etched, then the etch stop layer is etched, and then the halftone layer Etching is performed, and the side shield can be side-etched with a larger amount of side etching than that of the half-tone layer when etching the half-tone layer.

The half-tone mask of the aspect of the invention is manufactured by the above-described manufacturing method, whereby the half-tone mask of the aspect of the invention can be the same by changing the phase shift layer described above to a half-tone layer Manufacturing.

According to the aspect of the present invention, by simultaneously wet-etching the phase shift layer, the etching stop layer, and the light-shielding layer with the same etchant, the following effect can be exerted: the light-shielding layer can be laterally etched to be formed The size of the edge of the light-shielding pattern of the light-shielding layer disposed at a position receding from the side of the phase-shifting pattern deposited on the phase-shifting layer in a plan view becomes a phase-shifting mask suitable for the range of the edge-enhanced mask .

Moreover, according to the aspect of the present invention, by using the same etchant on the The etching stop layer and the light-shielding layer are simultaneously wet-etched, and the following effects can be achieved: the light-shielding layer is side-etched, and the side of the light-shielding pattern formed on the light-shielding layer can be manufactured to be disposed on the halftone layer in plan view. The size of the position where the side of the halftone pattern recedes further becomes the half dimming mask of the translucent area.

11: Phase shift layer

11a: Phase shift pattern

12: Etching stop layer

12a: Etching stop pattern

12b: Etching stop pattern

13: shading layer

13a: shading pattern

13b: shading pattern

15: Halftone layer

15a: halftone pattern

M: phase shift mask

M5: Half dimmer

MB: Mask base

S: Glass substrate (transparent substrate)

PR1: resist pattern

PR1a: photoresist layer

FIG. 1 is a schematic cross-sectional view showing a reticle base according to the first embodiment of the present invention.

2(a) to (h) are process diagrams showing a mask base, a phase shift mask, and a manufacturing method according to the first embodiment of the present invention.

FIG. 3 is a graph showing the changes of the side etching of each layer of the mask substrate, phase shift mask, and manufacturing method of the first embodiment of the present invention with time.

4 is a graph showing changes in the electrochemical relationship of the layers in the mask base, phase shift mask, and manufacturing method of the first embodiment of the present invention with time.

5 is a SEM (scanning electron microscope) photograph showing an experimental example of a method of manufacturing a mask base and a phase shift mask according to an embodiment of the present invention.

6 is a SEM photograph showing an experimental example of a method of manufacturing a mask base and a phase shift mask according to an embodiment of the present invention.

7 is a SEM photograph showing an experimental example of a method of manufacturing a mask base and a phase shift mask according to an embodiment of the present invention.

8 is a SEM photograph showing an experimental example of a method of manufacturing a mask base and a phase shift mask according to an embodiment of the present invention.

9 is a SEM photograph showing an experimental example of a method of manufacturing a mask base and a phase shift mask according to an embodiment of the present invention.

10 is a schematic cross-sectional view showing a second embodiment of the reticle base according to the embodiment of the present invention.

11(a) to (h) are diagrams showing the steps of a mask base, a half-light mask, and a manufacturing method according to a second embodiment of the present invention.

FIG. 12 is a graph showing the wavelength dependence of the transmittance of the half dimming mask of the second embodiment of the present invention.

Fig. 13 is data showing the wavelength dependence of the transmittance of the half-tone mask of the second embodiment of the present invention.

Hereinafter, the mask base, the phase shift mask, and the manufacturing method of the first embodiment of the present invention will be described based on the drawings.

FIG. 1 is a schematic cross-sectional view showing a reticle base in this embodiment. In the figure, symbol MB is a reticle base.

As shown in FIG. 1, the mask base MB of this embodiment is composed of a transparent substrate S, a phase shift layer 11 formed on the transparent substrate S, an etch stop layer 12 formed on the phase shift layer 11, and a The light-shielding layer 13 on the etching stop layer 12 is formed.

In the mask substrate MB of this embodiment, as described below, the phase shift layer 11, the etch stop layer 12, and the light shielding layer 13 can be etched using the same etchant.

As the transparent substrate S, a material excellent in transparency and optical isotropy is used, and for example, a quartz glass substrate can be used. The size of the transparent substrate S is not particularly limited, and is appropriately selected according to the substrate (for example, FPD substrate, semiconductor substrate) exposed using the photomask. In this embodiment, it can be applied to a substrate with a diameter of about 100 mm or a rectangular substrate from about 50 to 100 mm on one side to more than 300 mm on one side. Furthermore, 450 mm in length and 550 mm in width can also be used. A quartz substrate with a thickness of 8 mm or a substrate with a maximum side dimension of 1000 mm or more and a thickness of 10 mm or more.

Moreover, the flatness of the transparent substrate S can also be reduced by polishing the surface of the transparent substrate S. The flatness of the transparent substrate S can be, for example, 20 μm or less. As a result, the depth of focus of the mask becomes deeper, and it can greatly contribute to the formation of fine and high-precision patterns. Furthermore, the flatness is preferably a relatively small value of 10 μm or less.

The phase shift layer 11 is mainly composed of Cr, and specifically, can be selected from Cr alone, and oxides, nitrides, carbides, oxynitrides, carbide nitrides, and oxycarbide nitrides of Cr One of them may be formed by stacking two or more kinds selected from these materials.

The phase shift layer 11 is formed with a thickness (for example, 90 to 170 nm) capable of causing a phase difference of approximately 180° for any light in the wavelength range of 300 nm or more and 500 nm or less (for example, i-rays with a wavelength of 365 nm).

As the etch stop layer 12, one or more metals selected from Ni, Co, Fe, Ti, Si, Al, Nb, Mo, W, Cu, V, Ta, Zr, and Hf as main components can be used. For example, a Ni-Ti-Nb-Mo film can be used.

The etching stop layer 12 can be formed by, for example, a sputtering method, an electron beam evaporation method, a laser evaporation method, an ALD (atomic layer deposition) method, or the like.

In addition, as the film forming conditions of the etch stop layer 12, whether or not the film forming gas contains carbon dioxide can be set. When the film-forming gas of the etching stop layer 12 contains carbon dioxide, the etching stop layer 12 can be etched and removed using the following chromium etchant. In addition, when the film forming gas does not contain carbon dioxide, the etching stop layer 12 can be etched and removed without using the following chromium etchant.

The light-shielding layer 13 is composed of Cr as a main component, and specifically includes Cr and nitrogen. and then, The light shielding layer 13 may also have different compositions in the thickness direction. In this case, as the light-shielding layer 13, one or two selected from Cr alone, and oxides, nitrides, carbides, oxynitrides, carbonitrides, and oxycarbide nitrides of Cr may also be deposited Constituted above.

The light shielding layer 13 is formed with a thickness (for example, 80 nm to 200 nm) to obtain specific optical characteristics.

Here, the light-shielding layer 13 and the phase shift layer 11 are set as chromium-based thin films, and have been oxidized and nitrided, but if compared, the degree of oxidation of the phase shift layer 11 is greater than that of the light-shielding layer 13 and is not easy to nitride ( It is not easy to release electrons), so it becomes inert.

On the other hand, the light shielding layer 13 and the etch stop layer 12 are set such that the standard electrode potential becomes chromium trivalent (-0.13ξ ⁰ /V), nickel divalent (-0.245ξ ⁰ /V), and the light shielding layer 13 (chromium) becomes Being inert, the etching stop layer 12 (nickel) becomes active.

The mask base MB of this embodiment can be applied, for example, when manufacturing a phase shift mask M that is a patterned mask for a glass substrate for FPD.

The phase shift mask M has, for example, a phase shift layer (phase shift pattern) 11 capable of generating a phase difference of 180°, and the opening width of the light shielding pattern 13b formed in the light shielding layer 13 is wider than that formed in the phase shift The opening width of the phase shift pattern 11a of the transfer layer 11.

For example, according to the phase shift mask M, in the exposure process, the light in the wavelength region, especially the composite wavelength including g-rays (436 nm), h-rays (405 nm), and i-rays (365 nm) is used as the exposure light, thereby , Use the phase reversal effect to form the area where the light intensity becomes the smallest, which can make the exposure pattern clearer. With this phase shift effect, the pattern accuracy is greatly improved, so that a fine and high-precision pattern can be formed. The phase shift layer can be formed of chromium oxide, chromium oxynitride, chromium oxynitride carbide, or the like, and can also be formed of an oxide-based film, a nitride-based film, or an oxynitride-based film containing Si. In addition, the thickness of the phase shift layer is set to enable i-ray production The thickness of the phase difference is about 180°. Furthermore, the phase shift layer may be formed with a thickness that can cause a phase difference of approximately 180° between h-rays and g-rays. Here, "approximately 180°" means 180° or about 180°, for example, 180°±10° or less. According to this phase shift mask, by using light in the above-mentioned wavelength region, the pattern accuracy based on the phase shift effect can be improved, and a fine and high-precision pattern can be formed. With this, it is possible to manufacture a high-definition flat panel display.

Hereinafter, a method of manufacturing the mask base MB of this embodiment will be described.

FIG. 2 is a cross-sectional view showing a manufacturing step of a phase shift mask using the mask substrate in this embodiment, FIG. 3 is a graph showing the change of side etching in the mask substrate in this embodiment with time, FIG. 4 It is a graph showing the change in the electrochemical relationship with time in the reticle substrate in this embodiment.

As shown in FIG. 1, the mask base MB of this embodiment is first formed on the glass substrate S using a DC (direct current, direct current) sputtering method, etc., to sequentially form a phase shift layer 11 mainly composed of Cr. 、The etching stop layer 12 mainly composed of Ni. In the film formation of the etching stop layer 12, it is preferable to set it as a gas atmosphere containing carbon dioxide, and it is preferable to contain carbon such as methane at the same time.

Next, a light shielding layer 13 mainly composed of Cr is formed on the etch stop layer 12.

At this time, as the film forming conditions, sputtering can be performed in a state including argon, nitrogen (N ₂ ), or the like as a sputtering gas by DC sputtering using chromium as a target.

Further, as the sputtering progresses, the conditions are changed, whereby the light shielding layer 13 can be formed with a chromium layer on the glass substrate S side and a chromium oxide layer thereon.

Hereinafter, a method of manufacturing a phase shift mask from the mask substrate MB of this embodiment thus manufactured will be described.

Next, as shown in FIG. 2(a), it is formed on the light shielding layer 13 which is the uppermost layer of the mask base MB Photoresist layer PR1a. The photoresist layer PR1a may be a positive type or a negative type, and may be set to a positive type. As the photoresist layer PR1a, a liquid resist is used.

Next, as shown in FIG. 2(b), the photoresist layer PR1a is exposed, and as shown in FIG. 2(c), development is performed, thereby forming a resist pattern PR1 on the light shielding layer 13. The resist pattern PR1 functions as an etching mask for the light shielding layer 13, the etching stop layer 12, and the phase shift layer 11, and the shape is appropriately determined according to the etching patterns of the respective layers 11, 12, and 13. As an example, the resist pattern PR1 is set such that the phase shift region PS has an opening width corresponding to the opening width of the phase shift pattern 11a to be formed.

Then, as shown in FIG. 2( d ), the step of wet etching the light shielding layer 13, the etching stop layer 12, and the phase shift layer 11 through the resist pattern PR1 through the specific etching liquid is started.

As this etching step, the three layers 11, 12, and 13 are successively patterned by one etching process, and the etching of the light-shielding layer 13 is first started in accordance with the stacking order on the glass substrate S.

As the etchant, an etchant containing cerium diammonium nitrate can be used. For example, it is preferable to use cerium diammonium nitrate containing acids such as nitric acid or perchloric acid.

Here, the etch stop layer 12 has higher resistance to the etchant than the light-shielding layer 13. Therefore, first, only the light-shielding layer 13 is patterned to form a light-shielding pattern 13 a. The light-shielding pattern 13a has a shape corresponding to the opening width of the resist pattern PR1.

At this time, the portion of the light-shielding layer 13 corresponding to the resist pattern PR1 is removed in the entire thickness direction. Then, as shown in FIG. 2(e), the etching stopper layer 12 is continuously wetted with the same etchant Type etching.

Here, from the time when the light shielding layer 13 is etched to expose the etching stop layer 12, the same etching solution is used to start etching through the resist pattern PR1 without removing the resist pattern PR1 The etching of the stop layer 12 is engraved.

In addition, the etching rate of the etching stop layer 12 is smaller than the etching rate of the light shielding layer 13, and therefore, by appropriately selecting the film thickness of the etching stop layer 12, the light shielding pattern 13a can be formed and the etching stop pattern 12a can be formed.

Then, after forming the light-shielding pattern 13a, as shown in FIG. 2(e), since the etching stop layer 12 is etched to expose the phase shift layer 11, the resist pattern PR1 is removed without removing the resist pattern PR1 In this state, the phase etching layer 11 is etched using the same etchant.

Accordingly, since the light shielding pattern 13a is made of the same Cr-based material as the phase shift layer 11, and the side surface of the light shielding pattern 13a is exposed, the phase shift layer 11 is patterned to form the phase shift pattern 11a. The phase shift pattern 11a is shaped to have a specific opening width dimension.

Here, as shown in FIG. 2(f), while the phase shift layer 11 is being etched, the side etching rate of the light shielding layer 13 increases.

That is, from the time when the phase shift layer 11 is exposed, that is, when the etching of the phase shift layer 11 starts, the side of the light shielding layer 13 is etched relative to the previous side etching amount (the amount of side etching before the phase shift layer 11 is exposed) The amount increased by about 10 times.

Therefore, at the same time as the formation of the phase shift pattern 11a, the light-shielding pattern 13a is formed from the time when the phase shift layer 11 is etched to obtain a higher side etching amount, and therefore, the side face is further processed than the phase shift pattern 11a Etch. Then, as shown in FIG. 2(f), a light-shielding pattern 13b having a shape having an opening width larger than the opening width dimension of the phase shift pattern 11a is formed.

At this time, the light shielding layer 13 or the light shielding pattern 13a obtains a higher side etching amount from the time when the phase shift layer 11 is etched, thereby shortening the etching process time, thereby reducing the phase shift layer 11 or the phase shift Damage to pattern 11a.

Then, as shown in FIG. 2(g), the resist pattern PR1 is removed. The resist pattern PR1 can be removed Since a well-known resist stripping solution is used, detailed description is omitted here.

Then, as shown in FIG. 2(h), the etching stopper pattern 12a exposed from the side surface of the light shielding pattern 13b is wet-etched using a second etchant to produce an etching stopper pattern having an opening width corresponding to the light shielding pattern 13b 12b. As the second etching solution, those obtained by adding at least one selected from acetic acid, perchloric acid, hydrogen peroxide water, and hydrochloric acid to nitric acid can be suitably used.

Furthermore, the removal of the exposed etch stop pattern 12a after the removal of the resist pattern PR1 can also be performed by other methods.

From the above, as shown in FIG. 2(h), the opening width of the light-shielding region LR formed as the light-shielding pattern 13b (and the etching stop pattern 12b) is wider than that of the phase shift region PS formed as the phase shift pattern 11a The edge of the opening width is reinforced with a phase shift mask M.

Hereinafter, the change of the side etching amount (side etching rate) in the present embodiment will be described.

The etching in this embodiment continuously etches the light shielding layer 13, the etching stop layer 12, and the phase shift layer 11 by the same etchant.

Hereinafter, the time will be examined from the start of etching.

First, when an etchant is supplied to the mask substrate MB, the etchant is in contact with the light shielding layer 13 at the uppermost position exposed from the opening of the resist pattern PR1, and the portion of the light shielding layer 13 is etched. In this case, the side etching of the light-shielding layer 13 by an etchant is, for example, about 0.005 μm/10sec.

Then, the etching proceeds, and the etching of the upper light-shielding layer 13 reaches the lowermost part in the film thickness direction, and the etchant is in contact with the etching stop layer 12 in the middle in the film thickness direction.

In this case, the upper light-shielding layer 13 and the lower etching stop layer 12 are simultaneously wet-etched. Here, between the etch stop layer 12 on the lower side and the light-shielding layer 13 on the upper side, the composition There is a difference, so it arises from the electrochemically inert and active relationship.

As in this embodiment, when the upper light-shielding layer 13 is electrochemically inert with respect to the lower etch stop layer 12, that is, the lower etch stop layer 12 is electrified relative to the upper light-shielding layer 13 In the case of learning to be active, the active etching stop layer 12 is etched relative to the inert light-shielding layer 13.

However, since the etching stop layer 12 is originally made of a material with a high etching resistance to chromium etchant, the etching stop layer 12 is not etched as much as compared to the light shielding layer 13. Therefore, for example, the side etching amount of the etching stop layer 12 is less than about 0.001 μm/10sec relative to the side etching amount in the light shielding layer 13 of about 0.005 μm/10sec, so that the etching stop layer 12 is not so etched.

Here, a mechanism of removing, that is, etching, a film made of metal or the like by etching will be described.

Corrosion is mostly performed by electrochemical reactions (oxidation reactions, reduction reactions).

The ease of oxidation-reduction reaction differs according to the metal, and is expressed in the form of standard electrode potential. If the standard electrode potential is above its potential, a reduction reaction will occur, and if it is below its potential, a nitridation reaction will occur. Therefore, a metal with a lower standard electrode potential is more likely to be oxidized (active metal), and a metal with a higher standard electrode potential is less likely to be oxidized (inert metal). In addition, in this embodiment, the measured standard electrode potential is compared with a standard hydrogen electrode, and the higher metal is made inert and the lower metal is made active.

In the case of contacting metals with different standard electrode potentials, active metals promote oxidation and inert metals promote reduction. This corrosion is called dissimilar metal contact corrosion. In the oxidation reaction, active metals become metal ions and promote corrosion. That is, live metals are easily corroded.

In addition, the contact corrosion of dissimilar metals is related to the area of inert metals and active metals. If and lazy The area of the active metal is larger than that of the active metal, the reduction reaction requires fewer electrons, so oxidation will proceed slowly. If the area of the active metal is smaller than that of the inert metal, the electrons required for the reduction reaction will increase Therefore, the oxidation will proceed quickly.

The dissimilar metal contact corrosion occurs not only in the case of metal monomers, but also in the case of metal compounds (such as metal oxides, nitrides, carbides, and fluorides). In this case, the oxidized metal compound is less likely to continue to oxidize than the same metal compound that has not been oxidized. That is, it becomes difficult to release electrons and not easily become cations. Therefore, the ionization tendency becomes smaller and becomes inert.

In this way, in order to accurately etch the multilayer film by wet etching using a redox reaction, it is important that the difference between the standard electrode potential of the metal contained in the upper layer and the lower layer and the upper layer The difference between the ease of corrosion of the underlying layer (also referred to as the ease of flow of current when the etchant is the electrolyte and the membrane is the electrode).

Here, the standard electrode potential of the metal contained in the upper layer and the lower layer becomes "upper layer<lower layer (the standard electrode potential of the lower layer is greater than the standard electrode potential of the upper layer)" In this case, when the "upper layer is active and the lower layer is inactive", in wet etching, the etching rate of the lower layer becomes smaller than the etching rate of the upper layer.

Therefore, when the lower layer is to be etched, the etching rate of the lower layer becomes too small to be substantially etched, or when the upper layer is to be etched, the upper layer is etched The rate becomes too large to form a specific shape.

On the other hand, contrary to the above, the standard electrode potential of the metal contained in the upper layer and the lower layer becomes "upper layer>lower layer (the standard electrode potential of the lower layer is less than the upper layer Standard electrode potential)", it becomes "the upper layer is inert, In the case where the lower layer is active, in wet etching, the etching rate of the lower layer becomes larger than the etching rate of the upper layer.

Therefore, when the lower layer is to be etched, the etching rate of the lower layer becomes too large to form a specific shape, or when the upper layer is to be etched, the upper layer is etched. The case where the rate becomes too small to substantially prevent etching.

Therefore, consider the case where the standard electrode potential of the upper layer and the lower layer becomes "upper layer> lower layer", that is, the case where the upper layer is electrochemically inert relative to the lower layer In this case, it is possible to prevent the side etching in the lower layer from becoming too small, and the lower layer can be appropriately etched by wet etching.

It is considered that in this embodiment, the light-shielding layer 13 is directly deposited on the etch-stop layer 12, whereby the etch-stop layer 12 becomes a sacrificial electrode (active) and receives electrons from the light-shielding layer 13 (inert) to etch the etch-stop layer 12 The speed increases.

As the etching stop layer 12, one or more metals selected from Ni, Co, Fe, Ti, Si, Al, Nb, Mo, W, Cu, V, Ta, Zr, and Hf as main components are used, for example By using a Ni-Ti-Nb-Mo film, the relationship between the electrochemical inertness and the activity can be set, and the etching of the light shielding layer 13 can be controlled so that the side etching amount is about 0.005 μm/10sec. .

Consider the following case: Further etching is performed, the etching of the etching stop layer 12 in the middle of the film thickness direction reaches the lowermost part in the film thickness direction, and the etching of the phase shift layer 11 is started with the phase shift layer 11 on the lower side in contact with the etchant.

Here, the upper light-shielding layer 13, the middle etching stop layer 12 and the lower phase shift layer 11 are simultaneously wet-etched.

In this case, the etch stop layer 12 in the middle of the three layers functions as a conductor, in The relationship between the light shielding layer 13 on the upper side and the phase shift layer 11 on the lower side is electrochemically active and inert.

Here, as in this embodiment, when the upper light shielding layer 13 is electrochemically active relative to the lower phase shift layer 11, that is, the lower phase shift layer 11 shields the upper light shield When the layer 13 is electrochemically inert, the active light-shielding layer 13 is etched to a large extent relative to the inert phase shift layer 11. Furthermore, as the etching in the film thickness direction in the light-shielding layer 13 progresses, the difference in lateral etching corresponding to the lateral direction increases.

That is, contrary to the situation described in the relationship between the light shielding layer 13 and the etching stop layer 12, the standard electrode potential of the metal contained in the upper layer and the lower layer becomes "upper layer <lower layer" In this case, when the upper layer is active and the lower layer is inactive, when the upper layer is to be etched by wet etching, the etching rate of the upper layer can be increased.

Here, the upper light-shielding layer 13 serves as a light-shielding pattern 13a, and only the side wall portion of the light-shielding layer 13 is in contact with the etchant. Therefore, as a result, etching is performed in the direction perpendicular to the side wall, that is, in the lateral direction, and the amount of etching on the side surface Great.

It is considered that the increase in the amount of side etching in the light-shielding pattern 13a starts at the same time when the etching stop layer 12 is etched in the film thickness direction to expose the phase shift layer 11, that is, the etching start time of the phase shift layer 11.

FIGS. 3 and 4 show how the amount of side etching in the three layers 11, 12, and 13, and the relationship between electrochemical activity and inertness change as the etching progresses.

FIG. 3 is a graph showing the change of the side etching in each layer 13, 12, 11 of this embodiment with time, and FIG. 4 is a graph showing the change of the electrochemical relationship in each layer 13, 12, 11 of this embodiment with time. .

As shown in the left side of FIG. 3, during the period when only the light shielding layer 13 is etched shortly after the start of etching, as shown in the left column of FIG. 4, the light shielding layer 13 does not become an electrochemically active or inert comparison object. Therefore, the etching of the light shielding layer 13 is performed with a specific side etching amount based on the relationship between the film composition and the etchant.

The side etching amount in the light-shielding layer etching in this embodiment is 0.005 μm/10sec.

Then, as shown in the center of FIG. 3, the light shielding layer 13 is etched over the entire length in the film thickness direction. After the etching of the etching stop layer 12 starts, the light shielding layer 13 and the etching stop layer 12 are simultaneously etched. In the case of such etching, as shown in the center column of FIG. 4, the light shielding layer 13 is electrochemically inert with respect to the etching stop layer 12. Therefore, the etching of the light shielding layer 13 is performed with only the side etching amount during the etching of the light shielding layer 13, and the etching of the etching stop layer 12 becomes active and is performed with a smaller side etching amount.

The side etching amount in the etching stop layer etching in this embodiment is less than 0.005 μm/10sec.

Then, as shown in the right side of FIG. 3, the light shielding layer 13 is etched over the entire length in the film thickness direction, and the etching stop layer 12 is etched over the entire length in the film thickness direction. After the etching of the phase shift layer 11 starts, the etching stop layer 12 is visible In order to connect the light shielding layer 13 and the phase shift layer 11 to the conductor, it can be considered that the light shielding layer 13 and the phase shift layer 11 are simultaneously etched.

In the case of such etching, as shown in the right column of FIG. 4, the light shielding layer 13 is electrochemically active relative to the phase shift layer 11. Therefore, the etching of the light shielding layer 13 is performed with a side etching amount much larger than that of only the side etching in the etching of the light shielding layer 13, and the etching of the phase shift layer 11 becomes inert and is performed with a smaller side etching amount.

The side etching amount in the increased light-shielding layer etching in this embodiment is 0.066 μm/10sec.

In addition, the amount of side etching in the phase shift layer etching is about 0.005 μm/10sec.

In FIGS. 3 and 4, the chrome light-shielding film represents the light-shielding layer 11, the nickel thin film (ES film) represents the etch stop layer 12, and the chrome PSM film represents the phase shift layer 11.

In addition, in order to form a phase shift mask by processing three layers 11, 12, 13 in one etching as in this embodiment, the film thickness of the etching stop layer 12 must be set to a specific range.

When the film thickness of the etching stop layer 12 is not set to a specific range, especially when the film thickness of the etching stop layer 12 is too thin, in the initial etching of only the light shielding layer 13, the light shielding pattern 13a is formed as Before the specific shape corresponding to the resist pattern PR1, there is a portion where the etching stop layer 12 is removed in the film thickness direction to start etching of the phase shift layer 11, so that there is a possibility that a pattern of a specific shape cannot be formed. Alternatively, after the etching of the phase shift layer 11 starts, the etching of the phase shift layer 11 becomes too large by a certain amount, and there is a possibility that a pattern of a specific shape cannot be formed. Furthermore, the film thickness of the phase shift layer 11 becomes thinner as it approaches the edge of the pattern, so that a specific film thickness cannot be obtained, so the phase angle becomes smaller. In this case, there is a possibility that a bad situation in which the transmittance becomes large will occur, so it is not good.

In addition, when the etching stop layer 12 is too thick, there is a possibility that the time at which the etching of the phase shift layer 11 starts becomes too late and the opening width of the light shielding pattern 13a becomes too large, or the phase shift layer The etching of 11 ends at the bottom and causes a bad situation that does not exhibit a phase shift effect, so it is not good.

According to this embodiment, the width of the phase shift pattern 11a exposed from the light shielding pattern 13b in plan view can be determined according to the etching amount of the side surface of the light shielding layer 13 after the etching of the phase shift layer 11 and the phase shift layer 11 The amount of side etching, the thickness of the etching stop layer 12, the amount of change in the amount of side etching of the light shielding layer 13 and the light shielding pattern 13a, etc. are set.

Here, the horizontal etching rate (side etching amount) of the light shielding layer 13 and the phase shift layer 11 It can be achieved by setting the relationship between electrochemical inertness and liveliness. As the film-forming conditions for the light-shielding layer 13 and the phase shift layer 11 for setting the relationship between electrochemical inertness and activeness, the difference between specific materials in the two layers (oxide film and chromium film) and the presence or absence of nitrogen can be cited. Or the amount of nitrogen, the presence or absence of carbon dioxide, the amount of carbon dioxide, the presence or absence of methane (carbon) or the amount of methane, the film forming pressure, the film forming speed and other relationships.

As described above, in addition to the electrochemically inert and active relationship between the phase shift layer 11 and the light shielding layer 13, the side etching amount of the light shielding layer 13 relative to the etching amount of the phase shift layer 11 is set to shield the light The etching amount of the layer 13 changes in the in-plane direction (lateral direction) of the substrate.

When the etching processing time is increased, the rate of increase in the etching amount of the light shielding layer 13 becomes larger than the rate of increase in the etching amount of the phase shift layer 11. Therefore, as the etching amount of these layers changes, the width dimension of the light-shielding pattern 13b receding from the phase shift pattern 11a, that is, the width dimension of the phase shift region SP exposed by the phase shift pattern 11a relative to the light-shielding pattern 13b Variety.

At this time, in addition to the above-mentioned film thickness setting of the etching stop layer 12, the widthwise position of the upper end of the phase shift pattern 11a relative to the end of the etching stop pattern 12a and the widthwise position of the lower end of the phase shift pattern 11a also occur Variety. Therefore, the etching processing time is set in consideration of these.

Thereby, as shown in FIG. 1, the width dimension of the phase shift pattern 11 a that recedes from the light-shielding pattern 13 b in a plan view can be set to a specific range.

According to the present embodiment, the phase shift layer 11, the etching stop layer 12, and the light shielding layer 13 are sequentially deposited on the transparent substrate S to constitute the mask base MB.

A resist pattern PR1 is formed on the light shielding layer 13 of the mask base MB, only continuous wet etching is performed, and by setting the thickness of the etching stop layer 12, and setting the phase shift layer 11 and the light shielding layer The relationship between 13 is electrochemically inert and active, and the side etching rate of each layer 11, 13 and the etching processing time of each layer can be controlled to manufacture an edge-enhanced phase shift mask M.

Therefore, by performing resist formation only once, the pattern width composed of three layers can be accurately set, and high-definition phase-shifted light with high visibility can be produced in a short time with a small number of steps Hood M.

In addition, the light shielding layer 13 is composed of at least one selected from the group consisting of oxides, nitrides, carbides, oxynitrides, carbide nitrides, and oxycarbide nitrides of Cr, and has a film thickness that sufficiently exhibits the light shielding effect.

By having such a film thickness that fully exerts the light-shielding effect, there is a possibility that the etching time of the light-shielding layer 13 becomes longer than the etching time of the phase shift layer 11, but by setting the film of the etching stop layer 12 in the above manner The relationship between the thickness and the electrochemical inertness and activeness of the phase shift layer 11 and the light shielding layer 13 can sufficiently increase the side etching speed of the light shielding layer 13.

Thereby, the etching rate of the light shielding layer 13 and the phase shift layer 11 can be set to an appropriate range. Furthermore, by controlling the amount of etching, the line roughness of the phase shift layer 11 and the light-shielding layer 13 is substantially linear, and the pattern cross-section of these layers becomes substantially perpendicular to form a good pattern as a mask, which can improve the The CD accuracy of the formed light-shielding pattern 13b and phase shift pattern 11a. Furthermore, the cross-sectional shape of the film can be set to a shape close to vertical, which is good for a photomask.

In addition, by using the Ni-containing film as the etching stop layer 12, the adhesion strength to the light-shielding layer 13 and the phase shift layer 11 containing Cr can be sufficiently improved, and the light-shielding layer 13 and the phase shift layer can be utilized 11 Common wet etching solution for etching.

Therefore, all patterns can be formed in one continuous etching process. Furthermore, when the light shielding layer 13, the etching stop layer 12 and the phase shift layer 11 are etched with a wet etchant, the interface between the light shielding layer 13 and the etching stop layer 12 or the etching stop layer 12 and the phase shift layer will not be removed 11 Boundaries The surface penetrates the etching liquid. Therefore, the CD accuracy of the formed light-shielding pattern 13b and the phase shift pattern 11a can be improved, and the cross-sectional shape of the film can be made into a shape close to vertical, which is good for a photomask.

According to the present embodiment, the phase shift mask M has a phase shift pattern 11a capable of causing a phase difference of 180° for any light in a wavelength region of 300 nm or more and 500 nm or less, for example, g-rays, h-rays, and i-rays. Here, the width dimension of the phase shift pattern 11a formed adjacent to the edge of the light-shielding pattern 13b can be set to about 0.5 μm to 2.0 μm.

Furthermore, in the above embodiment, the setting of the etching rate of the phase shift layer 11 has been described in the form of setting by controlling the particle size, but it can also be set according to other factors such as film forming conditions, film composition, etc. .

Furthermore, in the mask base MB and the phase shift mask M of the above embodiment, a layer containing chromium has been described as the phase shift layer 11, but if the phase shift layer 11 and the light shielding layer can be set as described above The relationship between 13 is electrochemically inert and active and can be etched with a common wet etchant, the present invention is not limited to the above layer.

Also, the phase shift layer 11 may be formed by a plurality of layers.

Hereinafter, the mask base, the half-tone mask, and the manufacturing method of the second embodiment of the present invention will be described based on the drawings.

FIG. 10 is a schematic cross-sectional view showing the mask base in this embodiment, and FIG. 11 is a cross-sectional view showing the manufacturing steps of the half-tone mask using the mask base in this embodiment.

In this embodiment, the difference from the above-mentioned first embodiment is that a halftone layer is provided instead of the phase shift layer, and other components corresponding to the above-mentioned first embodiment are denoted by the same symbols and their description is omitted.

As shown in FIG. 10, the mask base MB of this embodiment is formed by a transparent substrate S The phase shift layer 11 on the bright substrate S, the etch stop layer 12 formed on the halftone layer 15 and the light shielding layer 13 formed on the etch stop layer 12 are formed.

In the mask base MB of this embodiment, the halftone layer 15, the etching stop layer 12, and the light shielding layer 13 can be etched using the same etchant.

As the half-tone layer 15, a semi-transmissive layer having a transmittance of 10% or more and 70% or less with respect to any wavelength range of 300 nm or more and 500 nm or less can be used. In addition, the halftone layer 15 and the light shielding layer 13 are preferably those containing Cr as a main component. Specifically, they can be selected from Cr monomers and Cr oxides, nitrides, carbides, oxynitrides, carbonitrides, and One of the oxidized carbonitrides is constituted, and it may be constituted by laminating two or more kinds selected from the above materials.

In the manufacturing method of the half-tone mask M5 of this embodiment, as shown in FIG. 11, by changing the phase shift layer 11 in the first embodiment to the half-tone layer 15, it can be manufactured in the same manner.

Here, the halftone layer 15 can generally be formed by a DC sputtering method using a Cr target. At this time, by introducing argon (Ar) or helium (He) as an inert gas and introducing oxygen (O ₂ ), nitrous oxide gas (N ₂ O), nitric oxide gas as a reactive gas (NO), nitrogen (N ₂ ), carbon dioxide gas (CO ₂ ), carbon monoxide gas (CO), methane gas (CH ₄ ), etc., and can make Cr oxides, nitrides, carbides, oxynitrides, carbonization Film formation of nitrides, oxycarbide nitrides, etc.

The transmittance of the half-light mask M5 of this embodiment is based on the Cr single component with Cr as the main component, the oxide of Cr, the nitride, the carbide, the oxynitride, the carbide nitride, the oxycarbide nitride The optical properties of each film or two or more laminated films selected from the above materials and the film thickness of each film are determined. Therefore, the transmittance can be controlled by controlling the film forming parameters and film thickness when forming a film by sputtering.

In particular, by forming the halftone layer 15 using a film mainly containing Cr, the wavelength dependence of the transmittance can be made very small. Specifically, the difference in transmittance at g-rays (426 nm), h-rays (405 nm), and i-rays (365 nm) in the wavelength range of 300 nm to 500 nm can be reduced to approximately 2% or less. Therefore, it is possible to provide a reticle base MB and a half dimmer M5 suitable for multi-color wavelength exposure used in an FPD exposure machine.

As an example of forming a half-light mask M5 using a film containing Cr as a main component in this embodiment, FIG. 12 shows a mask A with a transmittance of 45.9% and a transmittance of 28.2% under h-ray (405 nm). Spectral transmittance characteristics of mask B.

In addition, as an example of forming a half-light mask M5 using a film containing Cr as a main component in this embodiment, the g-rays (426 nm) and h-rays of the mask A and mask B shown in FIG. 12 are shown in FIG. 13. (405nm), i-ray (365nm) transmittance.

From the above results, it can be seen that when the half-light mask M5 is formed with a film containing Cr as the main component, the values of the difference in transmittance ΔT obtained by subtracting the transmittance of h-ray from the transmittance of g-ray are respectively 0.4% and -1.4%, the size of △T becomes less than 2%. From this, it can be seen that the mask A and the mask B formed of a film mainly composed of Cr have a small wavelength dependence of transmittance, and therefore, it is possible to form g-rays (426 nm) suitable for use in FPD exposure machines , Multi-wavelength exposure mask under h-ray (405nm), i-ray (365nm).

(Example)

Hereinafter, embodiments of the present invention will be described.

<Experiment example>

In order to confirm the above effect, the following experiment was performed. That is, on the glass substrate S, the chromium oxynitride carbide film of the phase shift layer 11 is formed by sputtering to a thickness of 122.0 nm, and the etch stop layer 12 is formed by Ni- Ti-Nb-Mo film, left at 105.0nm The total thickness on the right forms a film composed of a layer composed of a main component of chromium oxynitride and a layer composed of a main component of chromium oxynitride to form the light shielding layer 13 to obtain a mask base MB.

At this time, under the condition that the etching stop layer 12 contains methane and carbon dioxide as the sputtering gas so as to contain carbon, film formation is also performed so as to include NiOxTr.

In addition, it is assumed that the light shielding layer 13 contains nitrogen gas (N ₂ ) so as to contain nitrogen as a sputtering gas.

A resist pattern PR1 is formed on the reticle substrate MB, and the light shielding layer 13, the etching stop layer 12, and the phase shift layer 11 are continuously applied to the resist pattern PR1 using a mixed etchant of cerium diammonium nitrate and perchloric acid. Etching is performed to form the light-shielding pattern 13a, and then the etching stop layer 12 is etched to form the phase shift pattern 11a, and the light-shielding pattern 13b is formed, thereby obtaining an edge-enhanced phase shift mask M.

The weight ratio of the etching solution is set to "cerium diammonium nitrate: perchloric acid: pure water = 13~18: 3~5: 77~84". That is, if the weight of the etching solution is set to 100%, the weight of cerium diammonium nitrate is set to 13 to 18%, the weight of perchloric acid is 3 to 5%, and the weight of pure water is 77 to 84%.

Furthermore, the etching time using such an etching solution is changed in three stages so that the etching time exceeding the Just etching time as a reference, that is, the over-etching time becomes 60 sec, 180 sec, and 300 sec. Based on these conditions, the films shown in Experimental Examples 1 to 3 were manufactured, and the cross-sections of the films were taken to obtain SEM photographs.

This result is shown in FIGS. 5-7.

In addition, in FIGS. 5 to 7, the PS step portion represents the distance between the end of the phase shift pattern 11 a and the side end of the light-shielding pattern 13 b. In addition, the ES film thickness represents the film thickness of the etching stop layer 12.

From this result, it can be seen that the amount of side etching of the light-shielding layer 13 can be controlled by controlling the over-etching time, that is, the total etching time.

That is, it can be seen that the length of the PS step portion in the figure, that is, the distance from the end of the phase shift pattern 11a to the side end of the light-shielding pattern 13b can be set by controlling the etching time.

In addition, in this experimental example, it is clearly indicated by an image that a three-layer structure formed with a step difference is formed by one etching process.

Furthermore, the film thickness of the etch stop layer 12 described in the above Experimental Example 1 was changed, that is, the film shown in Experimental Examples 4 to 5 was produced under the conditions of the film thickness of 9.5 nm and 6.7 nm, and photographed A SEM photograph was obtained from the cross section of the film. In addition, the over-etching time was set to 60 sec.

These results are shown in Figures 8-9.

In addition, as in FIGS. 5 to 7, the PS step portion represents the distance from the end of the phase shift pattern 11 a to the side end of the light-shielding pattern 13 b, and the ES film thickness represents the film thickness of the etch stop layer 12.

From these results, it can be seen that in the case of forming a phase shift mask M with a three-layer structure with a step formed by one etching process, it is more important to set the film thickness of the etching stop layer 12, if it is not set to For a film thickness in a specific range, it is difficult to form a three-layer structure with rising edges by one etching process.

11‧‧‧ phase shift layer

12‧‧‧Etching stop layer

13‧‧‧ shading layer

MB‧‧‧Mask base

S‧‧‧Glass substrate (transparent substrate)

Claims (14)

A photomask base, characterized by comprising: a transparent substrate; a phase shift layer, which is deposited on the surface of the transparent substrate, with Cr as a main component; an etch stop layer, which is stacked on the phase shift layer; and a light shielding layer, It is deposited on the etch stop layer and mainly contains Cr; in the phase shift layer, the etch stop layer and the light shielding layer, the light shielding layer before the start of the etching of the phase shift layer is set to be relative After the etching stop layer is electrochemically inert, the light-shielding layer after the start of the etching of the phase shift layer is set to be electrochemically active relative to the phase shift layer; and by using the same etchant The phase shift layer, the etch stop layer, and the light shielding layer are etched, so that the side of the light shielding pattern formed on the light shielding layer can be arranged more in plan view than the side of the phase shift pattern stacked on the phase shifting layer The phase shift mask of the backward position. The reticle substrate according to claim 1, wherein the etching stop layer mainly contains at least one metal selected from Ni, Co, Fe, Ti, Si, Al, Nb, Mo, W, and Hf. The mask substrate according to claim 1 or 2, wherein in the light-shielding layer, the side etching amount of the phase shift layer, the etching stop layer and the light-shielding layer in the etching is equal to that of the phase shift layer Compared with the time before the start of etching, the time from the start of the etching of the shading layer becomes larger Mode setting. The mask substrate of claim 3, wherein the side etching amount of the light shielding layer is set to be more than 10 times greater than the etching start time of the phase shift layer from before the etching start time of the phase shift layer. The mask substrate according to claim 1 or 2, wherein the etching stop layer is set to a film thickness of 10 nm or more. A method of manufacturing a reticle base, characterized in that the reticle base is provided with: a transparent substrate; a phase shift layer, which is deposited on the surface of the transparent substrate, with Cr as a main component; and an etch stop layer, which is deposited on the above A phase shift layer; and a light-shielding layer, which is layered on the etching stop layer and contains Cr as a main component; and by etching the phase shift layer, the etching stop layer, and the light-shielding layer with the same etchant, it is possible Manufacturing a phase shift mask whose side of the light shielding pattern formed on the light shielding layer is arranged to recede from the side of the phase shifting pattern deposited on the phase shifting layer in a plan view; the method of manufacturing the above mask base has A step of sequentially depositing the phase shift layer, the etching stop layer and the light shielding layer on the transparent substrate, the etching stop layer contains carbon dioxide as a film forming gas atmosphere, and is selected from Ni, Co, Fe, Ti, Si At least one metal among Al, Nb, Mo, W, and Hf is the main component, and a film is formed by sputtering. A method for manufacturing a phase shift mask, characterized in that it is a method for manufacturing a phase shift mask using the mask substrate as in claim 1, and has a mask having a specific opening pattern formed on the light shielding layer Step; and the step of performing wet etching on the phase shift layer, the etching stop layer and the light shielding layer simultaneously with the same etchant through the formed mask. The method of manufacturing a phase shift mask according to claim 7, wherein in the step of simultaneously performing wet etching on the phase shift layer, the etching stop layer and the light shielding layer, the side etching amount of the light shielding layer is set to The side etching amount of the phase shift layer is about 4 to 5 times. A method of manufacturing a phase shift mask according to claim 7 or 8, wherein as the etchant, an etchant containing cerium diammonium nitrate is used. A phase shift reticle, characterized by comprising: a transparent substrate; a phase shift layer, which is deposited on the surface of the transparent substrate, with Cr as a main component; an etching stop layer, which is stacked on the above phase shift layer; and shading Layer, which is deposited on the etch stop layer, with Cr as the main component; in the phase shift layer, the etch stop layer, and the light shielding layer, the light shielding layer before the start of the etching of the phase shift layer is set To be electrochemically inert with respect to the above etching stop layer, The light-shielding layer after the etching start time of the phase shift layer is set to be electrochemically active relative to the phase shift layer; and the phase shift layer, the etching stop layer and the The light-shielding layer is etched, and the side of the light-shielding pattern formed on the light-shielding layer is disposed further back than the side of the phase-shift pattern deposited on the phase-shift layer in plan view. A photomask base, characterized by comprising: a transparent substrate; a half-tone layer, which is deposited on the surface of the transparent substrate, with Cr as a main component; an etching stop layer, which is laminated on the above-mentioned half-tone layer; and a light-shielding layer, which is laminated In the etching stop layer, Cr is the main component; and in the halftone layer, the etching stop layer, and the light-shielding layer, the light-shielding layer before the start of the etching of the halftone layer is set relative to the etching The termination layer is electrochemically inert, and the light-shielding layer after the etching start time of the halftone layer is set to be electrochemically active relative to the halftone layer; by using the same etchant on the halftone layer, the above The etching stop layer and the light-shielding layer are etched to manufacture a half-light mask in which the side of the light-shielding pattern formed on the light-shielding layer is arranged to recede from the side of the halftone pattern deposited on the halftone layer in a plan view. The reticle substrate of claim 11, wherein in the light-shielding layer, the side etching amount of the halftone layer, the etching stop layer and the light-shielding layer in the etching is before the start time of the etching of the halftone layer In contrast, it is set in such a manner that the point becomes larger from the start of the etching of the light-shielding layer. A method for manufacturing a reticle base, characterized in that the reticle base is provided with: a transparent substrate; a half-tone layer, which is deposited on the surface of the transparent substrate, with Cr as a main component; and an etch stop layer, which is deposited on the above-mentioned half Adjustment layer; and a light-shielding layer, which is deposited on the above-mentioned etching stop layer, with Cr as the main component; and by etching the half-tone layer, the etching stop layer, and the light-shielding layer with the same etchant, it can be manufactured and formed on The side of the light-shielding pattern of the light-shielding layer is arranged in a half-tone mask that is set back from the side of the half-tone pattern stacked on the half-tone layer in a plan view; the method of manufacturing the base of the mask has the order of the transparent substrate The step of stacking the halftone layer, the etch stop layer and the light shielding layer, the etch stop layer contains carbon dioxide as a film forming gas atmosphere, and is selected from Ni, Co, Fe, Ti, Si, Al, Nb, Mo, At least one metal in W and Hf is a main component, and a film is formed by sputtering. A half-tone mask is characterized by comprising: a transparent substrate; a half-tone layer, which is layered on the surface of the transparent substrate, with Cr as a main component; an etching stop layer, which is layered on the above-mentioned half-tone layer; and a light-shielding layer, which Layered on the etch stop layer, with Cr as the main component; and in the halftone layer, the etch stop layer, and the light-shielding layer, the light-shielding layer before the start of the etching of the halftone layer is set relative to the above The etch stop layer is electrochemically inert, Setting the light-shielding layer after the etching start time of the halftone layer to be electrochemically active relative to the halftone layer; etching the halftone layer, the etching stop layer and the light-shielding layer by using the same etchant The side of the light-shielding pattern formed on the light-shielding layer is arranged to recede from the side of the half-tone pattern deposited on the half-tone layer in a plan view.

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