JP2006071870A - Method for manufacturing mask blank and method for manufacturing mask - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress the occurrence of a defect in the base of a thin film (mask layer). <P>SOLUTION: The method for manufacturing a mask blank having a thin film as a mask layer formed on a light transmitting substrate 10, the thin film to be used as a mask layer for patterning a base (halftone film 12) by etching, is characterized in that: the thin film comprises a plurality of layers (light shielding films 14, 16); the thin film is formed in a plurality of steps by each layer; and the surface of each layer is cleaned every time of forming the layer of the thin film. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a mask blank manufacturing method and a mask manufacturing method.

  Conventionally, a halftone phase shift having a transparent substrate, a halftone material film laminated on the transparent substrate, and a metal film laminated on the halftone material film and capable of being selectively etched with respect to the halftone material film A mask blank is known (Patent Document 1).

Further, there is known a method of manufacturing a halftone phase shift mask blank by forming a metal film and an antireflection film on a halftone film and then performing scrub cleaning (Patent Document 2).
JP-A-8-101493 JP 2003-195479 A

  For example, in the production of a halftone phase shift mask blank, when a metal film or an antireflection film is formed on the halftone film, foreign matter may adhere during or before the film formation. When the foreign matter is firmly attached or deeply sunk into the film, the foreign matter is not removed and remains on the metal film and the antireflection film. Therefore, when scrub cleaning is performed after forming a metal film or an antireflection film, pinholes may be generated in the metal film or the antireflection film due to attached foreign matter.

  In addition, for example, when the base is etched using the metal film or the antireflection film as a mask layer, a defect may occur in the base due to the influence of pinholes in the metal film or the antireflection film as the mask layer. For example, when a halftone phase shift mask blank is produced using a halftone phase shift mask blank in which pinholes are generated in a metal film or an antireflection film, pinholes or bites are formed in the halftone film, and minute edge defects are further generated. May occur.

  Here, when a halftone phase shift mask blank is produced using a halftone phase shift mask blank in which pinholes are generated in a metal film or an antireflection film, the above-described defects do not always occur. When the hole just hits the opening of the halftone film, there is no problem in manufacturing the halftone phase shift mask.

  However, if a pinhole in the metal film or the antireflection film accidentally hits the opening of the halftone film pattern or hits a boundary portion of the halftone film pattern, a pattern defect occurs. For this reason, conventionally, there has been a problem that the manufacturing yield in manufacturing the mask is reduced and the manufacturing cost is increased due to the influence of pinholes generated in the metal film and the antireflection film.

  Conventionally, there is known a method of correcting a defect by, for example, a laser CVD method or a laser evaporation method for a pattern in which a defect has occurred. However, in a mask with a complex optical proximity correction (Optical Proximity Correction), for example, when a pinhole, a crack, or a minute edge defect occurs in the halftone film pattern, it is necessary to correct the defect. There was a problem that became difficult. Therefore, when manufacturing a mask with a complex optical proximity effect correction, it is particularly desirable that no pinhole is generated in the metal film or antireflection film used as the mask layer.

  The above-mentioned problem is similarly applied to a normal photomask blank in which a light shielding film is formed on a transparent substrate, a phase shift mask blank having a phase shift function by digging the surface of the transparent substrate to a predetermined depth, and the like. appear. Similar problems also occur in various phase shift mask blanks used for chromeless masks, for example.

  Accordingly, the present invention has been made in view of the above-described problems, and a mask blank manufacturing method that suppresses a decrease in manufacturing yield due to pattern defects during mask manufacturing due to a pinhole of a thin film serving as a mask pattern, and a mask An object is to provide a manufacturing method.

(Structure 1) In a method for manufacturing a mask blank in which a thin film used as a mask layer in the case of patterning a base by etching is formed on a light-transmitting substrate, the thin film is composed of a plurality of layers, and a plurality of the thin films are formed for each layer. A method for producing a mask blank, characterized in that the surface of each layer is washed each time the layers of the thin film are formed.
(Configuration 2) In a method for manufacturing a mask blank in which a thin film used as a mask layer in the case of patterning a base by etching is formed on a light-transmitting substrate, the thin film is composed of a plurality of layers, and the thin film is divided into a plurality of layers. Each of the thin film layers is formed by performing a surface defect inspection and removing in advance a convex defect that may be detached in a later manufacturing process. Mask blank manufacturing method.

In the present invention, in order to substantially eliminate defects in the mask layer that may lead to pattern defects in the underlying layer of the mask layer (thin film), the mask layer is divided into a plurality of times and pinholes are formed between the films. The cleaning is performed for the purpose of removing the induced foreign matter. With the configuration 1, it is possible to suppress the occurrence of pinholes, bites, minute edge defects, and the like in the base.
In addition, the present invention divides the mask layer into a plurality of times in order to substantially eliminate defects in the mask layer that may lead to pattern defects in the underlying layer of the mask layer (thin film). Inspection is performed, and convex defects that may be detached in a subsequent manufacturing process are removed in advance prior to the subsequent manufacturing process. With the configuration 2, it is possible to suppress the occurrence of pinholes, bites, minute edge defects, and the like in the base.
For example, when the underlayer is a halftone film in a halftone phase shift mask blank, the thickness of each layer of the thin film is, for example, 200 to 500 mm, more preferably 200 to 350 mm. The thickness of the thin film (the total thickness of all layers) is, for example, 400 to 1000 mm. Each layer in the thin film may be formed of the same material or may be formed of different materials.
The number of times the mask layer (thin film) is formed is set so that at least the mask layer can function as a mask when the underlying layer is etched using at least the mask layer as a mask. This base is, for example, a material having a phase shift function in the configuration 3, specifically, a halftone film or a translucent substrate in the configuration 4. In other words, even if a defect (pinhole) occurs due to the formation of a certain mask layer, as long as a defect (pinhole) does not occur at the same position during subsequent mask layer formation, a certain mask layer or more Is formed on the base (translucent substrate or halftone film). Thereby, when etching the base using the mask layer as a mask, generation of pattern defects in the base (translucent substrate or halftone film) caused by defects (pinholes) in the mask layer is prevented.
Note that the thin film used as the mask layer is not limited to the mask layer in the case of etching a material having a phase shift function such as a halftone film or a translucent substrate. The present invention can also be applied to a thin film of a mask layer made of an inorganic material when etching a light shielding film formed on a halftone film or a translucent substrate. The thin film made of an inorganic material is made of a material containing at least one of molybdenum, silicon, tantalum, and tungsten, for example, when the light-shielding film is a Cr-based material, specifically, Mo, MoSi, MoSiO , MoSiN, MoSiON, Si, SiO, SiN, SiON, Ta, TaB, W, WSi, TaSi, and the like.

(Structure 3) A method of manufacturing a mask blank according to Structure 1 or 2, wherein the thin film includes a light shielding film, and a material having a phase shift function is formed on a base of the light shielding film.
(Structure 4) The method for manufacturing a mask blank according to Structure 3, wherein the material having the phase shift function is a halftone film material and / or a translucent substrate.
When the light shielding film is used as a mask layer, the above-described problem becomes more remarkable. Therefore, the effect of the present invention is particularly exerted when a material having a phase shift function, specifically, a halftone film or a light-transmitting substrate is used as a base to be etched using the mask layer as a mask.

(Structure 5) A mask manufacturing method for manufacturing a mask using the mask blank according to any one of Structures 1 to 4, wherein a resist pattern is formed on the thin film, and the resist pattern is used as a mask. A first step of forming a thin film pattern by performing etching 1 and a second step of patterning a base material formed under the thin film by performing second etching at least using the thin film pattern as a mask; And a third step of removing a part or all of the thin film pattern.
Generation of defects in the pattern of the underlying material caused by thin film (mask layer) defects is prevented, and the mask manufacturing yield is improved. Since the load of the mask correction process is reduced, the manufacturing cost is not increased.
In the second step of patterning the base material, the base material is patterned using the resist film and the thin film (mask layer) as a mask, and the resist film is peeled off before patterning the base material, and the thin film (mask layer) is used as a mask. Patterning may be performed. In order to further suppress the occurrence of pattern defects in the underlying material due to thin film (mask layer) defects, it is preferable to pattern the underlying material using the former resist film and thin film (mask layer) as a mask.

(Structure 6) The method for manufacturing a mask according to Structure 5, wherein the first etching is dry etching.
There is a possibility that an oxide film is formed on the surface by dividing the film formation of the thin film (mask layer) in the above-described mask blank manufacturing method into a plurality of times and putting a cleaning step between the film formations. Depending on the etching, the cross-sectional shape of the thin film pattern may be affected. By making the etching dry etching, a change in the cross-sectional shape of the thin film pattern due to the oxide film formed on the surface can be suppressed by inserting a cleaning step between the films.

  According to the present invention, it is possible to suppress the occurrence of defects in the base of the thin film (mask layer).

Hereinafter, a mask blank manufacturing method and a mask manufacturing method of the present invention will be described with reference to the drawings.
FIG. 1 is a view for explaining a method of manufacturing a halftone phase shift mask blank according to the first embodiment of the present invention. FIG. 2 is a diagram for explaining a manufacturing method for manufacturing a halftone phase shift mask using the halftone phase shift mask blank according to the first embodiment of the present invention. FIG. 3 is a view for explaining a mask blank manufacturing method for forming a phase shift mask by digging a surface of a translucent substrate according to a second embodiment of the present invention to a predetermined depth. FIG. 4 is a diagram for explaining a manufacturing method for manufacturing a phase shift mask using a mask blank according to the second embodiment of the present invention.

  First, the manufacturing method of the halftone phase shift mask blank and the manufacturing method of the halftone phase shift mask according to the first embodiment of the present invention will be described with reference to FIGS. The halftone phase shift mask blank and the halftone phase shift mask are, for example, a mask blank and a mask for ArF excimer laser exposure or F2 excimer laser exposure.

Method for manufacturing halftone phase shift mask blank
Step 1-a
A translucent substrate 10 having a predetermined size whose surface is precisely polished is prepared. As a material of the translucent substrate 10, it is sufficient that the translucent substrate 10 has translucency with respect to an exposure wavelength. When a KrF excimer laser or an ArF excimer laser is used as an exposure light source, for example, synthetic quartz glass is generally used. When an F2 excimer laser is used as an exposure light source, for example, fluorine-doped synthetic quartz glass, calcium fluoride, or the like is used.

Step 1-b
A halftone film 12 is formed on one main surface of the translucent substrate 10. Examples of the film forming method include a sputtering method, a CVD method, and a vacuum evaporation method. After the halftone film formation, the surface of the halftone film 12 may be cleaned for the purpose of removing foreign substances in the halftone film 12 or on the film. As a cleaning method, any method that does not change the optical characteristics of the halftone film 12 may be used. For example, physical cleaning without chemical action is preferable. Examples of the physical cleaning include scrub cleaning, megasonic cleaning applying ultrasonic waves, functional water cleaning using gas-dissolved water, and the like using an aqueous solution that does not damage the halftone film 12.
The material of the halftone film 12 may be a single layer or a plurality of layers. The single-layer halftone film 12 may be made of metal, a material containing at least one of oxygen and nitrogen in silicon (silicon), or a material containing at least one of carbon, fluorine, and hydrogen, chromium oxide, fluorine. And chromium oxide. The metal here is one or more metals selected from titanium, vanadium, niobium, molybdenum, tantalum, and tungsten. Further, the halftone film 12 can be configured to include a high transmittance film mainly responsible for the phase shift function and a low transmittance film mainly responsible for the light shielding function. As the low-transmittance film, a film made of one or two or more kinds selected from metal or silicon, or oxides, nitrides, or the like thereof can be used. Specifically, aluminum, titanium, vanadium, chromium, Examples thereof include films made of one or more materials selected from zirconium, niobium, molybdenum, lanthanum, tantalum, tungsten, silicon, and hafnium, and nitrides thereof. As the high transmittance film, a thin film based on silicon (silicon) such as silicon oxide, silicon nitride, silicon oxynitride is preferable because relatively high transmittance can be easily obtained with respect to exposure light in the ultraviolet region. These materials may contain a trace amount of metal.
FIG. 1B shows a state in which the foreign matter 22 adheres to the surface of the halftone film 12 by transport or the like after the surface of the halftone film 12 is cleaned.

Step 1-c
A light shielding film 14 is formed on the halftone film 12. Examples of the film forming method include a sputtering method, a CVD method, and a vacuum evaporation method. The thickness of the light shielding film 14 at this time is such that when the halftone film 12 is etched using the light shielding film 14 as a mask layer, the etching time of the halftone film 12 and the etching of the light shielding film 14 with respect to the etchant of the halftone film 12 are performed. It is preferable that the film thickness be obtained from the product of speeds. For example, when the etching time for patterning the halftone film 12 is ET and the etching rate of the light shielding film 14 is ER1, the film thickness d1 of the light shielding film 14 satisfies d1> ER1 × ET. In addition, the thickness of the light shielding film 14 is set to be equal to or larger than the thickness that exhibits the function as the light shielding film in consideration of the optical density OD. The material of the light shielding film 14 is preferably a material having an etching characteristic different from that of the halftone film 12 and an etching selectivity of 10: 1 or more. When silicon (silicon) is included as the material of the halftone film 12, the material of the light shielding film 14 is preferably a material including chromium.
After the light shielding film 14 is formed, a defect inspection on the surface of the light shielding film 14 may be performed.

Step 1-d
Foreign matter adhering to the surface of the light shielding film 14 and foreign matter entering the light shielding film 14 are removed (cleaned). The cleaning method may be any method that does not change the optical characteristics of the surface of the light shielding film 14. For example, physical cleaning without chemical action is preferable. Examples of the physical cleaning include scrub cleaning, megasonic cleaning applying ultrasonic waves, functional water cleaning using gas-dissolved water, etc., using an aqueous solution that does not damage the light shielding film 14.
FIG. 1D shows a state in which foreign matter 24 newly adheres to the surface of the light shielding film 14 after the surface of the light shielding film 14 is cleaned.
The scrub cleaning is, for example, cleaning performed by bringing a rotating cleaning tool into contact with the light shielding film 14. In scrub cleaning, for example, the translucent substrate 10 is rotated by an electric motor or the like while supplying the cleaning liquid to the light shielding film 14 from the cleaning liquid supply nozzle. In this state, the light-shielding film 14 is cleaned by pressing and contacting the light-shielding film 14 on the light-transmitting substrate 10 while rotating the cleaning tool in a direction opposite to the light-transmitting substrate 10. The cleaning tool is, for example, a cup-shaped or cylindrical brush or sponge.
Megasonic cleaning is, for example, cleaning performed by supplying a solvent to which ultrasonic waves are applied to the light-shielding film 14 as a cleaning liquid. The frequency of this ultrasonic wave is preferably about 1 MHz or more. In the megasonic cleaning, for example, the light-shielding film 14 is cleaned by moving (swinging) an ultrasonic cleaning nozzle that ejects the cleaning liquid with respect to the translucent substrate 10.
The functional water cleaning is, for example, cleaning performed by spraying a mixed fluid obtained by mixing a gas and a solvent onto the light shielding film 14 as a cleaning liquid. In the functional water cleaning, for example, the light-shielding film 14 is cleaned by moving (swinging) an ultrasonic cleaning nozzle that ejects the cleaning liquid with respect to the translucent substrate 10.

Step 1-e
A light shielding film 16 is formed on the light shielding film 14. The light shielding film 16 may have an antireflection function. The film thickness of the light shielding film 16 at this time is the same as described above. When the halftone film 12 is etched using the light shielding film 16 as a mask layer, the etching time of the halftone film 12 and the etchant of the halftone film 12 are reduced. The film thickness is preferably equal to or greater than the film thickness obtained from the product of the etching rates of the light shielding film 16. For example, when the etching time for patterning the halftone film 12 is ET and the etching rate of the light shielding film 16 is ER2, the film thickness d2 of the light shielding film 16 satisfies d2> ER2 × ET. In addition, the film thickness of the light shielding film 16 is set to be equal to or larger than the film thickness that exhibits the function as the light shielding film in consideration of the optical density OD.
The materials of the light shielding films 14 and 16 to be formed into a plurality of layers may be materials having different etching characteristics, but materials that can be patterned with the same etchant are preferable.

Step 1-f
The foreign matter adhering to the surface of the light shielding film 16 and the foreign matter entering the light shielding film 16 are washed to obtain a halftone phase shift mask blank. As a cleaning method, the same method as in step 1-d can be employed. Note that a resist film may be further formed on the light shielding film 16 to form a halftone phase shift mask blank.
The thin film of the mask layer may be formed by more layers (light shielding films). For example, when the thin film of the mask layer is composed of n layers (n is an integer of 2 or more), the thickness of each layer is set to di (i is an integer satisfying 1 ≦ i ≦ n). When the film thickness of the layer that takes the etching time is di ′ and the etching rate of the layer is Eri ′, the total etching time (Equation 1) of each layer obtained by dividing the film thickness di of each layer by the etching rate ERi of each layer, The difference obtained by subtracting the etching time (di ′ / ERi ′) obtained by dividing the film thickness di ′ of the layer that takes the longest etching time by the etching rate ERi ′ is set to be larger than the etching time ET of the halftone film. That is, when the etching time of the layer that takes the longest etching time is ETi ′ (= di ′ / ERi ′) among the plurality of thin films constituting the mask layer, the total etching other than the layer that takes the longest etching time. The time is set longer than the etching time ET of the halftone film. With such a film thickness, the function of the mask layer can be exhibited by the other (n-1) layers even when a defect occurs in any one of the n layers stacked. .

2. Method for Manufacturing Halftone Phase Shift Mask In the method for manufacturing the halftone phase shift mask shown in FIG. 2, the halftone film 12 is patterned using the light shielding films 14 and 16 (only) formed on the halftone film 12 as a mask. It is an example. As described above, the halftone film 12 may be patterned using the resist film 18 and the light shielding films 14 and 16 formed on the halftone film 12 as a mask.

Step 2-a
After forming the resist film 18 on the halftone phase shift mask blank obtained by the manufacturing method described above, a drawing process is performed to form a desired pattern. As a drawing method, either electron beam drawing or laser drawing may be used.

Step 2-b
After drawing a desired pattern, development processing is performed to form a resist pattern on the light shielding films 14 and 16, and the light shielding films 14 and 16 are etched using the resist pattern as a mask to form a light shielding film pattern. The light shielding films 14 and 16 may be etched by either dry etching or wet etching, but dry etching is preferred for the reasons described above. When the light shielding films 14 and 16 are made of a material containing chromium, the etchant for dry etching the light shielding films 14 and 16 is performed in a mixed gas atmosphere containing chlorine gas and oxygen gas. The pressure and power during dry etching are adjusted as appropriate.

Step 2-c
Next, the resist pattern formed on the patterns of the light shielding films 14 and 16 is removed with a stripping solution. The stripping solution is appropriately selected according to the resist type. For example, an alkaline aqueous solution is used. Next, the underlying halftone film 12 is etched using the light shielding films 14 and 16 as a mask to form a halftone film pattern. The halftone film 12 may be etched by either dry etching or wet etching, but dry etching is preferred. When the halftone film 12 contains silicon (silicon), the etchant used when dry-etching the halftone film 12 is performed in a mixed gas atmosphere containing a fluorine-based gas containing fluorine and an oxygen gas. The pressure and power during dry etching are adjusted as appropriate.

Step 2-d
Next, a resist is again applied and formed on the light shielding films 14 and 16 pattern, a drawing / development process is performed to form a resist pattern, and the light shielding film pattern is formed by the same method as described above using the resist pattern as a mask. Further, by performing an etching process, a halftone phase shift mask in which a light shielding film pattern is formed on the halftone film pattern is obtained. In the halftone phase shift mask according to the present invention, the light shielding film pattern may not be formed on the halftone film pattern. In that case, the light shielding film pattern may be removed after the halftone film pattern is formed by etching using the light shielding film pattern as a mask.

  Next, the manufacturing method of the substrate digging type phase shift mask blank and the manufacturing method of the phase shift mask according to the second embodiment of the present invention will be described with reference to FIGS.

Manufacturing method of substrate digging type phase shift mask blank
Step 3-a
A translucent substrate 30 having a predetermined size whose surface is precisely polished is prepared. As the material of the translucent substrate 30, the same materials as described above can be used. FIG. 3A shows a state in which the foreign matter 42 is attached to the surface of the light-transmitting substrate 30 by transport or the like after the surface of the light-transmitting substrate 30 is cleaned.

Step 3-b
A light shielding film 32 is formed on the translucent substrate 30. Examples of the film forming method include a sputtering method, a CVD method, and a vacuum evaporation method. The film thickness of the light shielding film 32 at this time is calculated by multiplying the etching time of the substrate and the etching rate of the light shielding film 32 with respect to the etchant of the substrate when the light transmissive substrate 30 is etched using the light shielding film 32 as a mask. It is preferable that the thickness be equal to or greater than the thickness obtained. In addition, the thickness of the light shielding film 32 is set to be equal to or larger than the thickness that exhibits the function as the light shielding film in consideration of the optical density OD. The light shielding film 32 may be made of a material having an etching characteristic different from that of the translucent substrate 30, and a material having an etching selection ratio of 10: 1 or more is preferable. For example, the material of the light shielding film 32 is preferably a material containing chromium. After the light shielding film 32 is formed, a defect inspection on the surface of the light shielding film 32 may be performed.

Step 3-c
Next, the foreign matter adhering to the surface of the light shielding film 32 and the foreign matter entering the light shielding film 32 are removed (cleaned). As a cleaning method, the same method as described above can be used. FIG. 3C shows a state in which foreign matter 44 newly adheres to the surface of the light shielding film 32 after the surface of the light shielding film 32 is cleaned.

Step 3-d
A light shielding film 34 is formed on the light shielding film 32. The light shielding film 34 may have an antireflection function. The film thickness of the light shielding film 34 at this time is also the same as described above. When the light transmissive substrate 30 is etched using the light shielding film 34 as a mask, the etching processing time of the light transmissive substrate 30 and the light transmissive substrate 30 The film thickness is preferably equal to or greater than the film thickness obtained from the product of the etching rate of the light shielding film 34 with respect to the etchant. In addition, the film thickness of the light shielding film 34 is set to be equal to or larger than the film thickness that exhibits the function as the light shielding film in consideration of the optical density OD. Similarly to the above, the light shielding films 32 and 34 to be formed into a plurality of layers may be made of materials having different etching characteristics, but materials that can be patterned with the same etchant are preferable.

Step 3-e
Foreign matter adhering to the surface of the light shielding film 34 and foreign matter entering the light shielding film 34 are washed to obtain a phase shift mask blank. As the cleaning method, the same method as described above can be adopted.

Manufacturing Method of Phase Shift Mask The manufacturing method of the phase shift mask shown in FIG. 4 is an example in which the light-transmitting substrate 30 is etched and dug using the light shielding films 32 and 34 (only) as a mask. The translucent substrate 30 may be etched and dug using the resist film 36 and the light shielding films 32 and 34 formed on the translucent substrate as a mask.

Step 4-a
After the resist film 36 is formed on the phase shift mask blank obtained by the above-described manufacturing method, a drawing process is performed to form a desired pattern. As a drawing method, either electron beam drawing or laser drawing may be used.

Step 4-b
After drawing a desired pattern, development processing is performed to form a resist pattern on the light shielding films 32 and 34.

Step 4-c
Using the resist pattern as a mask, the light shielding films 32 and 34 are etched to form a light shielding film pattern. As an etching method and etching conditions for the light shielding films 32 and 34, the same method as described above can be employed.

Step 4-d
Next, the resist pattern formed on the light shielding film pattern is removed with a stripping solution. The stripping solution is appropriately selected according to the resist type. Next, using the light shielding film pattern as a mask, the underlying light-transmitting substrate is etched by 30 to dig a predetermined depth of the substrate surface. As an etching method, either dry etching or wet etching may be used, but dry etching is preferable. As an etchant for dry-etching the light-transmitting substrate 30, it is performed in a mixed gas atmosphere containing a fluorine-based gas containing fluorine and an oxygen gas. The pressure and power during dry etching are adjusted as appropriate.

Step 4-e

  Next, a resist film 38 is formed on the light shielding films 32 and 34, and a drawing process is performed to form a pattern corresponding to a region where the light shielding films 32 and 34 are to be removed. As a drawing method, either electron beam drawing or laser drawing may be used.

Step 4-f
After drawing the pattern, development processing is performed to form a resist pattern on the light shielding films 32 and 34.

Step 4-g
The light shielding films 32 and 34 are etched using the resist pattern as a mask, and a part of the pattern of the light shielding films 32 and 34 formed on the surface of the translucent substrate 30 is removed. As an etching method and etching conditions for the light shielding films 32 and 34, the same method as described above can be employed.

Step 4-h
Next, the resist pattern is removed with a stripping solution to obtain a phase shift mask. The stripping solution is appropriately selected according to the resist type.

The present invention can be applied to various phase shift mask blanks and phase shift masks in general other than the above embodiment. For example, the present invention can be applied to a mask blank for a Levenson mask and a Levenson mask. Further, in the manufacture of various phase shift mask blanks, a thin film used as a mask layer in the case of patterning a layer of a material having a phase shift function is composed of a plurality of layers, and each layer is formed in a plurality of times.
In addition, the present invention is not limited to a mask layer for a material layer having a phase shift function, but a mask layer made of an inorganic material for etching a light shielding film formed on a halftone film or a light-transmitting substrate. Is also applicable. The thin film made of an inorganic material can be a material containing at least one of molybdenum, silicon, tantalum, and tungsten when the light-shielding film is a Cr-based material, for example. Moreover, the film thickness of this thin film is about 50-1000 mm, for example. Moreover, this thin film may be used as a mask layer together with the resist layer, or may be used alone as a mask layer after removing the resist layer.

  Examples of the present invention will be described in detail below. A halftone phase shift mask blank for ArF excimer laser exposure was prepared using a DC magnetron sputtering apparatus. Specifically, a mixed target of molybdenum and silicon (molybdenum: silicon = 8 mol: 92 mol, pressure: 0.1 Pa) is used in a mixed gas atmosphere of argon and nitrogen (argon: nitrogen = 10%: 90%). A half-tone film (film thickness: 67 nm) of nitrided molybdenum and silicon (MoSiN) was formed on the synthetic quartz glass substrate by reactive sputtering.

Next, a chromium nitride (CrN) light-shielding film (thickness 25 nm) is formed by reactive sputtering in a mixed gas atmosphere of argon and nitrogen (argon: nitrogen = 80%: 20%, pressure 0.3 Pa) using a chromium target. ) Was formed.
Next, scrub cleaning was performed on the surface of the light shielding film.
Next, using a chromium target, in a mixed gas atmosphere composed of argon and methane (argon: methane = 95%: 5%, pressure 0.3 Pa), by reactive sputtering, chromium carbide (CrC) and further with argon. A light-shielding film having an antireflection function for chromium oxynitride (CrON) by reactive sputtering in a mixed gas atmosphere of nitrogen oxide (argon: nitrogen monoxide = 85.5%: 15.5%, pressure 0.3 Pa) A film thickness of 25 nm) was formed.

Thereafter, scrub cleaning was performed on the surface of the light shielding film to obtain a halftone phase shift mask blank. 1000 halftone phase shift mask blanks were produced by the method described above.
Next, a resist film was applied and formed on the light-shielding film, and electron beam drawing and development processing were performed to form a resist pattern.
Next, a light shielding film pattern is formed by dry etching with a mixed gas of chlorine and oxygen using the resist pattern as a mask, and the resist pattern is peeled off using a resist stripping solution, and then carbon tetrafluoride is used using the light shielding film pattern as a mask. A halftone film pattern was formed by dry etching with a mixed gas of oxygen and oxygen.
Next, a resist film is further applied to and formed on the light shielding film pattern, a resist pattern is formed by performing electron beam drawing and development, and a desired light shielding film pattern is formed on the halftone film using the resist pattern as a mask. The film was peeled off to produce a halftone phase shift mask.

  When 1000 pieces of the obtained halftone phase shift masks were subjected to pattern inspection by an inspection apparatus, the halftone film patterns were all good without pattern defects such as pinholes and quarrels.

(Comparative Example 1)
In Example 1 described above, 1000 halftone phase shift masks were produced in the same manner as in Example 1 except that no cleaning step was provided between the light-shielding films formed of a plurality of layers.

When the obtained 1000 halftone phase shift masks were subjected to pattern inspection by an inspection apparatus, 13 halftone film patterns had pattern defects such as pinholes and quarks.
As in the above-described embodiment, by providing a cleaning step between the light-shielding films formed of a plurality of layers, pattern defects of the halftone film due to the light-shielding film (mask layer) can be prevented.

  A substrate digging type phase shift mask blank was produced using a DC magnetron sputtering apparatus. Specifically, using a chromium target, chromium nitride (on a synthetic quartz glass substrate) by reactive sputtering in a mixed gas atmosphere of argon and nitrogen (argon: nitrogen = 80%: 20%, pressure 0.3 Pa). A light shielding film (film thickness 40 nm) of CrN) was formed.

Next, scrub cleaning was performed on the surface of the light shielding film.
Next, using a chromium target, in a mixed gas atmosphere composed of argon and methane (argon: methane = 95%: 5%, pressure 0.3 Pa), by reactive sputtering, chromium carbide (CrC) and further with argon. A light shielding film (film) having an antireflection function of chromium oxynitride (CrON) by reactive sputtering in a mixed gas atmosphere of nitrogen oxide (argon: nitrogen monoxide = 85.5%: 15.5%, pressure 0.3 Pa) 30 nm thick).
Thereafter, scrub cleaning was performed on the surface of the light shielding film to obtain a substrate digging type phase shift mask blank. 1000 substrate digging type phase shift mask blanks were produced by the above-described method.

Next, a resist film was applied and formed on the light-shielding film, and electron beam drawing and development processing were performed to form a resist pattern.
Next, a light shielding film pattern is formed by dry etching with a mixed gas of chlorine and oxygen using the resist pattern as a mask, and after the resist pattern is peeled off, the underlying synthetic glass substrate is made of tetrafluoride using the light shielding film pattern as a mask. A recess having a depth of 190 nm was formed on the substrate surface by dry etching using a mixed gas of carbon fluoride and oxygen.
Next, a resist film was formed on the light shielding film, and a resist pattern was formed on the light shielding film by drawing and developing an electron beam in a region corresponding to the region where the light shielding film was to be removed.

Next, using the resist pattern as a mask, a part of the light shielding film pattern formed on the surface of the synthetic quartz glass substrate is removed by dry etching with a mixed gas of chlorine gas and oxygen gas. Finally, the resist pattern is removed with a stripping solution. A substrate digging type phase shift mask was produced by removing the substrate.
When the obtained 1000 sheets of the substrate dug type phase silat masks were subjected to pattern inspection by an inspection apparatus, they were all good with no phase defects.

(Comparative Example 2)
In Example 2 described above, 1000 substrate digging type phase shift masks were produced in the same manner as in Example 2 except that the cleaning step was not provided between the formation of the light shielding films composed of a plurality of layers.
When a pattern inspection was performed on the obtained 1000 substrate dug type phase shift masks by an inspection apparatus, phase defects formed on the substrate surface were generated on 16 substrates.
As in the above-described embodiment, by providing a cleaning step between the light-shielding films formed of a plurality of layers, it is possible to prevent phase defects caused by etching the substrate due to the light-shielding film (mask layer). .

  A halftone phase shift mask blank for ArF excimer laser exposure was produced using a DC magnetron sputtering apparatus. Specifically, a mixed target of molybdenum and silicon (molybdenum: silicon = 8 mol%: 92 mol%, pressure: 0.1 Pa) is used, and a mixed gas atmosphere of argon and nitrogen (argon: nitrogen = 10%: 90%) Then, a halftone film (film thickness: 67 nm) of molybdenum and silicon (MoSiN) nitrided on a synthetic quartz glass substrate was formed by reactive sputtering.

Next, a chromium nitride (CrN) light-shielding film (thickness 25 nm) is formed by reactive sputtering in a mixed gas atmosphere of argon and nitrogen (argon: nitrogen = 80%: 20%, pressure: 0.3 Pa) using a chromium target. ) Was formed.
Next, the substrate with the light shielding film was put into a defect inspection apparatus, and surface information of the light shielding film was obtained. The surface information includes surface shape information of convex portions (particles) and concave portions (pinholes), positional information of the convex portions and the concave portions, and information on the sizes of the convex portions and the concave portions. ing. From the surface information described above, a convex portion that may be detached in a later manufacturing process is specified, and the needle-shaped member is brought into contact with the convex portion and slid to exist on the surface of the light shielding film. All the defects on the convex portion were removed.

Next, using a chromium target, in a mixed gas atmosphere composed of argon and methane (argon: methane = 95%: 5%, pressure: 0.3 Pa), by reactive sputtering, chromium carbide (CrC), and further, argon and Anti-reflective function of chromium oxynitride (CrON) by reactive sputtering in nitrogen monoxide mixed gas atmosphere (argon: nitrogen monoxide = 85.5%: 15.5%, pressure: 0.3 Pa) A light-shielding film having a thickness of 25 nm was formed.
Next, in the same manner as described above, the substrate with the light shielding film is put into the defect inspection apparatus, and after acquiring the surface information of the light shielding film, the needle-like defect is detected against the defect of the convex portion that may be detached in a later manufacturing process. By bringing the members into contact with each other, all the defects of the convex portions present on the surface of the light shielding film were removed, and a halftone phase shift mask blank was obtained. 1000 halftone phase shift mask blanks were produced by the method described above.

  When a pattern inspection was performed with an inspection apparatus on the halftone phase shift mask obtained in the same manner as in Example 1 described above, the halftone film pattern was all good without pattern defects such as pinholes and quarks.

  As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range as described in the said embodiment. It will be apparent to those skilled in the art that various modifications or improvements can be added to the above embodiment. It is apparent from the description of the scope of claims that embodiments with such changes or improvements can be included in the technical scope of the present invention.

It is a figure for demonstrating the manufacturing method of the halftone type phase shift mask blank which is 1st embodiment of this invention. It is a figure for demonstrating the manufacturing method which manufactures a halftone type phase shift mask using the halftone type phase shift mask blank which is 1st embodiment of this invention. It is a figure for demonstrating the manufacturing method of the mask blank for digging the surface of the translucent board | substrate 10 which is 2nd embodiment of this invention to predetermined depth, and forming a phase shift mask. It is a figure for demonstrating the manufacturing method which manufactures a phase shift mask using the mask blank which is 2nd embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Translucent substrate, 12 ... Halftone film, 14 ... Light shielding film, 16 ... Light shielding film, 18 ... Resist film, 22 ... Foreign material, 24 ... Foreign material, DESCRIPTION OF SYMBOLS 30 ... Translucent substrate, 32 ... Light shielding film, 34 ... Light shielding film, 36 ... Resist film, 38 ... Resist film, 42 ... Foreign material, 44 ... Foreign material

Claims (6)

In the method for manufacturing a mask blank in which a thin film used as a mask layer in the case of patterning the base by etching is formed on a translucent substrate,
The thin film comprises a plurality of layers,
Forming the thin film by dividing it into multiple layers,
A method for producing a mask blank, wherein the surface of each layer is washed each time the thin film is formed. In the method for manufacturing a mask blank in which a thin film used as a mask layer in the case of patterning the base by etching is formed on a translucent substrate,
The thin film comprises a plurality of layers,
Forming the thin film by dividing it into multiple layers,
Perform a surface defect inspection each time each thin film layer is formed,
A method of manufacturing a mask blank, wherein a convex defect that may be detached in a subsequent manufacturing process is removed in advance. 3. The method of manufacturing a mask blank according to claim 1, wherein the thin film includes a light shielding film, and a material having a phase shift function is formed on a base of the light shielding film. 4. The method of manufacturing a mask blank according to claim 3, wherein the material having the phase shift function is a halftone film material and / or a translucent substrate. A mask manufacturing method for manufacturing a mask using the mask blank according to any one of claims 1 to 4,
Forming a resist pattern on the thin film;
A first step of forming a thin film pattern by performing a first etching using the resist pattern as a mask;
A second step of patterning a base material formed under the thin film by performing a second etching using at least the thin film pattern as a mask;
And a third step of removing a part or all of the thin film pattern. 6. The method of manufacturing a mask according to claim 5, wherein the first etching is dry etching.

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