WO2007013540A1

WO2007013540A1 - Mask blank fabrication method and exposure mask fabrication method

Info

Publication number: WO2007013540A1
Application number: PCT/JP2006/314832
Authority: WO
Inventors: Masahiro Hashimoto; Toru Fukui; Takao Higuchi; Hiroshi Shiratori
Original assignee: Hoya Corporation
Priority date: 2005-07-28
Filing date: 2006-07-27
Publication date: 2007-02-01
Also published as: KR20080034004A; JP2007058200A; TW200710561A

Abstract

It is possible to suppress CD irregularities in a plane in a mask pattern of an exposure mask based on sensitivity difference between the center portion and the peripheral portion of a mask blank, so as to match, for example, a half pitch 65 nm node in a semiconductor device. When resist liquid is dropped from a nozzle onto a substrate surface, a distance of substrate rotation center where the resist liquid has dropped and the rpm of the substrate are adjusted in the following range so as to suppress resist sensitivity increase at the position where the resist liquid has dropped on the substrate surface as compared to the other positions. The resist liquid which has dropped is spread to form a resist pool at the substrate central portion. The resist pool is spread to the peripheral portion of the substrate surface by centrifugal force and then dried to form a resist film.

Description

Specification

Mask blank manufacturing method and exposure mask manufacturing method

Technical field

[0001] The present invention relates to a method for manufacturing a mask blank having a resist coating process in which a resist solution is uniformly spin-coated on a rectangular substrate and a resist film is formed with reduced in-plane variation in resist sensitivity, and This mask blank force It is related with the manufacturing method of the mask for exposure which manufactures the mask for exposure, Specifically, It is related with the manufacturing method of the mask blank for semiconductor device manufacture, and the manufacturing method of the exposure mask for semiconductor device manufacture. Background art

[0002] Conventionally, when a resist film is formed on a rectangular substrate or on a substrate with a thin film having a thin film formed on the substrate, a rotary coating apparatus that rotates the substrate and applies a resist solution is provided. The resist spin coating method used is generally used. As a typical example of this spin coating method, a resist spin coating method described in Patent Document 1 for forming a uniform resist film without forming thick films at four corners of the substrate is known.

In this resist spin coating method, the product of the number of rotations and the rotation time of the substrate is selected so as to be, for example, 24000 (r pm * second) or less, and the rotation time is selected to be 20 seconds or less. After setting the substrate rotation speed and substrate rotation time and dropping the resist solution onto the substrate, the substrate is rotated for the substrate rotation time at the substrate rotation speed set as described above, and the film thickness of the resist film is made uniform. Then, the substrate is rotated at a rotation speed lower than the substrate rotation speed of this homogenization process, and the uniformity of the resist film thickness obtained by the homogenization process is maintained. A drying process for drying the resist film is performed. Also, as a uniform resist coating method for preventing uneven coating of the resist solution, the resist spin coating method described in Patent Document 2 is known. The resist coating method described in Patent Document 2 attempts to reduce coating unevenness by dropping the coating solution so that the coating solution draws an annular locus on the surface of the object to be coated.

Patent Document 1: Japanese Patent Publication No. 4-29215

Patent Document 2: JP-A-57-130570 Disclosure of the invention

Problems to be solved by the invention

However, in recent years, there has been a growing demand for pattern miniaturization of transferred objects such as semiconductor devices, and exposure light used in photolithography technology has been shortened to ArF excimer lasers and F2 excimer lasers. In addition, the focal length of lenses used in exposure apparatuses is becoming shorter. Furthermore, in an exposure mask used in photolithography technology and a mask blank for manufacturing the exposure mask, a light-shielding film that blocks light with respect to the exposure wavelength of the exposure light described above, and a phase shift. Phase shift films are rapidly being developed, and various film materials have been proposed.

[0005] Since the trend of such innovations in optical lithography technology will continue, the accuracy required for exposure masks and mask blanks is becoming stricter year by year. For example, at a half-pitch 65nm node, which is a demand for pattern miniaturization of semiconductor devices as the transfer target, the line width dimension (CD: Critical Dimen- sion) of the pattern line in the mask pattern of the exposure mask is the target of interest. The “in-plane CD variation”, which varies in-plane with respect to the line width dimension (CD) of the line, is 5. lnm for the line and space pattern and 3.6 nm for the isolated line pattern. This is becoming difficult to achieve with exposure mask manufacturing technology.

Factors attributable to “in-plane CD variation” in the mask blank manufacturing process include in-plane uniformity of the resist film thickness formed on the substrate or the substrate with the thin film, and in-plane uniformity of the pre-beta treatment temperature after the resist film formation. Sex and so on. Factors arising from “in-plane CD variation” in the exposure mask manufacturing process include in-plane uniformity of post-exposure beta processing temperature and in-plane uniformity of development processing.

Note that the above “in-plane CD variation” refers to a line such as a SEM for length measurement after a resist pattern is formed by drawing and developing the resist film using a test pattern for in-plane uniformity evaluation. Using a width dimension measuring device, pattern dimensions are measured and evaluated at a plurality of predetermined locations in the plane up to the outer periphery of the central force of the substrate.

[0006] Even if the in-plane uniformity in the mask blank manufacturing process and the exposure mask manufacturing process due to the above "in-plane CD variation" is improved, the "in-plane CD variation" is still improved. The problem of not being able to occur. In particular, in recent years, in order to miniaturize the pattern of semiconductor devices, it is necessary to increase the sensitivity and resolution of resist films, and the use of chemical amplification resist films that meet these requirements has been used. The problem became more prominent.

When the tendency of in-plane CD variation was observed by the above evaluation method, the CD was over at the center position of the substrate, that is, the position where the resist solution dropped on the substrate, that is, the sensitivity was increased, and the CD on the outer periphery of the substrate was It was confirmed that under-sensitivity, that is, low sensitivity. This is because chemically amplified resists generally consist of a polymer, PAG (Photo Acid Generator) and Quencher! However, when a chemically amplified resist is formed on a mask blank, especially when a chemically amplified resist solution is dropped on the substrate, certain components tend to stay near the center even if the substrate rotates. As a result, a variation in the amount of the constituent material of the resist film occurs near the center of the mask blank and at the outer periphery, and this causes a difference between the substrate center and the outer periphery in the mask blank surface. Feeling Variations occur, affecting the CD variation in the mask blank surface was found that it is difficult to meet the demand for fine patterns of the transfer member.

The object of the present invention has been made in consideration of the above-mentioned circumstances, and suppresses in-plane CD variation in the mask pattern of the exposure mask based on the sensitivity difference between the vicinity of the center and the periphery of the mask blank. Thus, a mask blank manufacturing method capable of realizing an exposure mask capable of meeting a request for pattern miniaturization of a transfer target, for example, a request for adapting to a half pitch 65 nm node in a semiconductor device, and the mask An object of the present invention is to provide a method of manufacturing an exposure mask that uses a blank to manufacture an exposure mask. Means for solving the problem

[0008] As means for solving the above problems,

In the mask blank manufacturing method that works on the first means, when the resist solution is dropped on the substrate surface, the resist solution is dropped on the substrate surface so that the dropping position of the resist solution is different. The resist solution is spread to form a resist pool near the center of the substrate. This resist pool is diffused to the periphery of the substrate surface by centrifugal force and then dried. Thus, a resist film is formed.

A mask blank manufacturing method that works on the second means is the first means in which a nozzle for dropping the substrate and the resist solution is provided so that the resist solution dropping position is different with time. It is characterized by relatively moving.

According to the first or second means, when the resist solution is dropped on the substrate surface by the nozzle means, the distance from the center of rotation of the substrate below the resist droplet, The resist solution is dropped in the shape of a slant by adjusting the relative movement speed of the substrate and the nozzle.

The mask blank manufacturing method that works as a fourth means is that the nozzle force When the resist solution is dropped on the substrate surface, the resist solution is more sensitive than the other locations at the position where the resist solution is dropped on the substrate surface. The resist solution is dropped by adjusting the distance from the substrate rotation center at the position below the resist droplet and the rotation speed of the substrate within the following range so as to suppress the formation of the resist droplet. A resist pool is formed in the vicinity, the resist pool is diffused to the peripheral portion of the substrate surface by centrifugal force, and then dried to form a resist film.

However, the distance from the substrate rotation center at the position below the resist droplet is 1 cm to 5 cm, and the rotation speed of the substrate is 0.5 rpm to 50 rpm.

A mask blank manufacturing method that works on the fifth means is a mask blank manufacturing method including a resist coating process in which a resist solution is formed on a rectangular substrate to form a resist film, and the resist coating process includes: A dropping step of spreading a resist solution on the surface of the substrate, a dropping step; a uniforming step of uniformly spreading the dropped resist solution over the entire surface of the substrate to form a resist film having a uniform thickness; A drying process for drying the resist film formed to a desired film thickness. In the dropping process, the resist liquid is applied to the substrate when a predetermined amount or more of the resist liquid capable of obtaining the required film thickness is dropped by the nozzle force. The distance from the substrate rotation center at the position below the resist droplet and the number of rotations of the substrate are adjusted in the following range so that the sensitivity of the resist is suppressed compared to other positions at the position where it is dropped on the surface. And on It is characterized in that dropped on the surface of the substrate by dispersing Les resist solution.

However, the distance from the center of rotation of the substrate below the resist droplet is 1 cm or more and 5 cm or less. The rotation speed of the plate shall be 0.5 rpm or more and 50 rpm or less.

[0009] A method for manufacturing a mask blank that works on the sixth means is characterized in that, in the fourth or fifth means, the resist solution is dropped onto the substrate surface in the form of a slanting ball.

In the fifth or sixth means, the method for producing a mask blank that works on the seventh means is that the dropping step includes a step of applying a resist solution of a predetermined amount or more that can obtain a required film thickness from the nozzle to the substrate. When dripping onto the surface, the dripping position is changed.

[0010] In any one of the first to seventh means, the mask blank manufacturing method that works on the eighth means is that the dropping of the resist solution is performed while rotating the substrate or around the center of the surface of the substrate. The resist solution is dropped at a position eccentric to the center of the substrate surface while moving the nozzle.

[0011] In the mask blank manufacturing method according to the ninth means, in any one of the first to eighth means, the resist solution is dropped by using the resist solution dropped on the surface of the substrate as the center of the surface. It is characterized by including the process of extending to a maximum.

[0012] A method for manufacturing a mask blank that works on the tenth means includes the step of spreading the resist liquid to the center of the surface of the substrate in addition to the dropping of the resist liquid in the ninth means. After the completion of the dropping of the resist liquid force, the resist liquid force is a step of waiting until it spreads to the center of the surface.

[0013] In the eighth or ninth means, the method for producing a mask blank that works on the eleventh means includes a nozzle that drops a resist solution during the rotation of the substrate, and the center of the surface. The center force on the surface of the substrate on a straight line passing through is moved to an eccentric position.

[0014] In the eleventh means, in the eleventh means, the dripping step in the method of manufacturing the mask blank, which acts on the twelfth means, is a straight line passing through the center of the surface through a nozzle for dropping the resist solution while the substrate is rotating. The eccentric positional force of the surface of the substrate is moved toward the center of the surface of the substrate.

[0015] A method for manufacturing a mask blank that is applied to the thirteenth means is the method according to the eleventh means, wherein the dropping step is performed at a position where the center of the surface of the substrate or the central force is decentered during the rotation of the substrate. The nozzle for dropping the resist solution on the device is moved outward on a straight line passing through the center of the surface.

[0016] A mask blank manufacturing method which is effective for the fourteenth means is characterized in that, in any of the first to thirteenth means, the resist blank is made of the chemically amplified resist.

[0017] In the mask blank manufacturing method according to the fifteenth means, in any one of the first to fourteenth means, the substrate is a substrate with a thin film in which a thin film serving as a mask pattern is formed on the substrate. It is characterized by this.

According to a sixteenth means for producing a mask blank, the thin film is made of a material force containing chromium.

[0018] A method for manufacturing an exposure mask that is applied to the seventeenth means patterns a resist film of the mask blank manufactured by the mask blank manufacturing method according to any one of the first to sixteenth means. Then, a resist pattern is formed, and a mask pattern is formed using this resist pattern as a mask to manufacture an exposure mask. The invention's effect

[0019] According to the first to fourth and fifteenth means, when the resist solution is dropped onto the substrate surface, the resist solution is dropped in a ball shape such that the dropping position of the resist solution on the substrate surface is different. In this case, the substrate and the nozzle for dropping the resist solution are moved relative to each other so that the resist solution dropping position becomes different with time. The resist solution is dropped by adjusting the distance of the substrate rotation central force at the dropping position from 1 cm to 5 cm and adjusting the number of substrate rotations from 0.5 rpm to 50 rpm. As a result, the resist solution is not concentrated and dripped at one place on the substrate surface, and it is also possible to suppress the concentration of the components constituting the resist solution affecting the resist sensitivity from being concentrated at the position of the dropping position. It is possible. Therefore, the resist liquid is applied to an exposure mask provided with a mask pattern formed using the resist pattern formed by exposure and development processing on the resist film of the mask blank produced by the above manufacturing method as a mask. The line width dimension (CD) of the pattern line of the mask pattern varies in the plane due to variations in the sensitivity of the resist film at the dropping position of the film and its vicinity and other positions. It can suppress “in-plane CD variation”. As a result, it is possible to realize an exposure mask that can meet the demand for pattern miniaturization of a transfer target (for example, generation after a half pitch 65 nm node in a semiconductor device). Although the mechanism by which “in-plane CD variation” is suppressed by the above-mentioned resist solution dropping method is not clear, the resist solution pressure on the substrate surface is weak when the resist solution is dripped onto the substrate surface. Resist liquid dropping start force The resist pool can be formed near the center of the substrate while the resist liquid gently spreads on the substrate surface until the dropping is completed. In other words, the pressure of the resist solution against the substrate surface under the resist droplets is weakened, so that the components that make up the resist solution that affects the resist sensitivity are at the dropping position on the substrate surface due to the surface condition of the substrate surface. In-plane CD variation is considered to be suppressed by suppressing the stagnant suspension and by uniformly dispersing the components of the resist solution that affect the resist sensitivity on the substrate surface. According to the means, in the dropping step in the resist coating step, a predetermined amount or more of resist liquid force that provides a required film thickness is dispersed and dropped on the surface of the substrate. Since it is not dripped concentrated on one spot on the surface, it is possible to prevent dripping marks from being generated on the surface of the substrate and to mask the resist pattern formed from the resist film. In the exposure mask provided with the mask pattern formed as “in-plane CD variation” in which the line width dimension (CD) of the pattern line of the mask pattern varies in the plane. As a result, it is possible to realize an exposure mask that can meet the demand for pattern miniaturization of a transfer target (for example, a half pitch 65 nm node in a semiconductor device).

[0020] According to the seventh means, in the dropping step in the resist coating step, the dropping position force of a predetermined amount or more of the resist solution that can obtain the required film thickness is changed on the surface of the substrate. Can be dispersed and dropped onto the substrate surface, so that the resist liquid can be prevented from being dropped on the substrate surface, and in-plane CD variation in the mask pattern of the exposure mask can be suppressed.

[0021] According to the eighth means, in the dropping step, the resist is placed at a position eccentric to the center of the substrate surface while rotating the substrate or rotating the nozzle around the center of the substrate surface. Since the resist solution is dropped, the resist solution can be dispersed and dropped on the surface of the substrate. That is, it is possible to suppress the concentration of the components constituting the resist solution affecting the sensitivity of the resist, where a predetermined amount or more of the resist solution is concentrated and dropped at one place on the surface of the substrate. Therefore, it is possible to suppress resist film droplet traces on the substrate surface, the position under and near the resist droplet, and other positions, and to suppress variations in the sensitivity of the resist film, as well as in-plane CD in the mask pattern of the exposure mask. Variations can be suppressed, and the resist solution can be dropped symmetrically with respect to the center of the substrate surface.

[0022] According to the ninth or tenth means, the dropping step force includes the step of spreading the resist solution dropped onto the surface of the substrate to the center of the surface, so that in the homogenizing step of rotating the substrate, The resist solution can be spread uniformly over the entire surface of the substrate, and a resist film with good in-plane film thickness uniformity can be formed.

[0023] According to the eleventh means, in the dropping step, the central force on the surface of the substrate is dropped on the straight line passing through the center of the surface during rotation of the substrate. Since it is moved, the resist solution dripped onto the surface of the substrate can be spread quickly to the center of this surface, and the resist solution dripped onto the surface of the substrate can be spread quickly and uniformly outward of the substrate surface. be able to.

[0024] According to the twelfth means, in the dropping step, a nozzle for dropping the resist solution at a position eccentric from the center of the surface of the substrate during rotation of the substrate is applied on a straight line passing through the center of the surface. Since the substrate is moved in the central direction, the resist solution dropped on the surface of the substrate can be quickly spread to the center of the surface.

[0025] According to the thirteenth means, in the dropping step, the nozzle for dropping the resist solution at the center of the surface of the substrate or the position where the central force is decentered is provided at the center of the surface during rotation of the substrate. Since the resist solution dripped onto the surface of the substrate can be quickly spread to the center of the surface, the resist solution dripped onto the surface of the substrate can be spread on the surface of the substrate. It can be spread quickly and uniformly outward.

[0026] According to the fourteenth means, the chemically amplified resist has a low viscosity and is easily dried, but even with this chemically amplified resist, the resist solution dripping traces are formed on the surface of the substrate. Generation, chemical amplification at the position below and near the resist droplet, and other positions It is possible to suppress concentration of components constituting the resist solution affecting the resist sensitivity of the mold resist at the dropping position. Therefore, in-plane CD variation in the mask pattern of the exposure mask due to variation in sensitivity of the resist film in the mask blank can be suppressed.

[0027] According to the sixteenth means, a chromium-based material containing at least one element of oxygen, nitrogen, and fluorine in order to provide a thin film having a material strength containing chromium and further to provide an antireflection function on the surface of the thin film In the case of a strong thin film, the surface state of the thin film becomes relatively rough, and the sensitivity tends to be high at the position where the resist solution is dropped. By applying the above method of the invention, in-plane CD variation in the mask pattern of the exposure mask can be suppressed.

According to the seventeenth means, a resist pattern of the mask blank manufactured by the mask blank manufacturing method according to any one of the first to sixteenth means is patterned to form a resist pattern. Since an exposure mask is manufactured by forming a mask pattern using a mask, in-plane CD variation in the mask pattern of the exposure mask can be suppressed. It is possible to realize an exposure mask that can be adapted to a half-pitch 65nm node in the device. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

FIG. 1 is a side sectional view showing a spin coating apparatus for performing a resist coating process in an embodiment of a mask blank manufacturing method according to the present invention. FIG. 4 (A) is a cross-sectional view showing a mask blank manufactured as shown in FIG. FIG. 4B is a cross-sectional view showing an exposure mask in which the mask blank force of FIG. 4A is also manufactured.

[0029] The mask blank 10 shown in FIG. 4 is manufactured by forming a thin film 14 to be a mask pattern 13 to be transferred onto a transfer surface on a main surface 12 of a rectangular substrate 11 by sputtering, vapor deposition, or CVD. A mask blank 10 is manufactured by forming a resist film 16 on the surface 19 of the thin film 14 of the substrate 15 with a thin film by a resist coating process. The manufacturing method of the mask blank 10 includes a case where the mask blank 10 is manufactured by directly forming the resist film 16 on the main surface 12 of the rectangular substrate 11.

[0030] The thin film 14 also changes optically with respect to exposure light (eg, ArF excimer laser). Specifically, a light-shielding film that shields exposure light and a phase shift film that changes the phase of exposure light (this phase shift film also includes a black-tone film having a light-shielding function and a phase shift function) Included). The thin film 14 is not limited to a single layer and may be laminated. As the laminated film of the thin film 14, for example, a laminated film of a light shielding film or a laminated film in which a phase shift film and a light shielding film are laminated may be used.

In addition, the mask blank 10 has a mask pattern formation region 17 (FIG. 3) in the central region of the thin film 14 of the substrate 15 with a thin film. In this mask pattern forming region 17, when the substrate 15 with a thin film is used as an exposure mask 18, a mask pattern 13 for transferring and forming a circuit pattern of a transfer target such as a semiconductor substrate is formed. It is an area. This mask pattern formation region 17 is a region of 132 mm X 132 mm in the center of the thin film 14 of the substrate 15 with a thin film when the mask blank 10 has a size of 152 mm X 152 mm, for example, when the mask blank 10 has a size of 152 mm X 152 mm. is there.

Note that the mask blank 10 is a transmissive mask blank or a reflective mask blank. In the case of a transmissive mask blank, a translucent substrate was used as the substrate 11, and a mask blank having a light shielding film formed as the thin film 14 and a phase shift film (including a halftone film) formed as the thin film 14 were formed. Phase shift mask blank. In the case of a reflective mask blank, a substrate having a low thermal expansion coefficient is used as the substrate 11, and the mask blank 10 has a light reflecting multilayer film and a light absorber film serving as a mask pattern sequentially on the substrate 11. It is formed. These light reflecting multilayer film and light absorber film are the thin film 14.

Now, the resist coating process in which the resist film 16 is formed by applying a resist solution to the surface 19 of the thin film 14 of the substrate with thin film 15 will be described below. In this resist coating process, a spin coater 20 shown in FIG. 1 is used.

The spin coater 20 is dropped by a spinner chuck 21 on which the substrate 15 with thin film is placed and rotatably held, and a nozzle 22 for dropping the resist solution 26 on the surface 19 of the substrate 15 with thin film. The resist solution 26 is provided on the lower part of the cup 23 and the cup 23 for preventing the resist solution 26 from scattering to the outside of the thin film substrate 15 by the rotation of the thin film substrate 15 and to the periphery of the spin coater 20. In addition, there is a drainage means (not shown) that collects and drains the resist solution 26 scattered outside the thin-film substrate 15 during the rotation of the thin-film substrate 15. Above The pinner chuck 21 is connected to a motor 25, and the driving of the motor 25 causes the thin film-coated substrate 15 held by the spinner chuck 21 to rotate under a rotation condition described later.

In the resist coating process using the spin coater 20, first, the substrate 15 with a thin film is transferred to the spinner chuck 21 of the spin coater 20 by a substrate transport device (not shown). The substrate 15 with a thin film is held on it. Next, while rotating the substrate 15 with a thin film through the spinner chuck 21 by the motor 25, a dropping step of spreading the resist solution 26 from the nozzle 22 onto the surface 19 of the thin film 14 of the substrate 15 with the thin film, and a motor While rotating the substrate with thin film 15 by 25, the dropped resist solution 26 is uniformly spread over the entire surface 19 of the thin film 14 of the substrate 15 with thin film to form a resist film 16 having a uniform film thickness. The surface of the thin film 14 of the substrate 15 with the thin film 15 is sequentially carried out by the crystallization process and the drying process of drying the resist film 16 having a uniform film thickness while rotating the substrate 15 with the thin film by the motor 25. Then, a resist film 16 is formed.

Here, the resist solution 26 is not particularly limited. However, the resist solution 26 has a viscosity exceeding lOmPa's and a high molecular weight resist composed of a high molecular weight resin having an average molecular weight of 100,000 or more, or a viscosity of lOmPa '. These include novolak-type resists having an average molecular weight of less than 100,000 and novolak-type resins having a power such as dissolution inhibitors, and chemically amplified resists having a power such as polyhydroxystyrene-type resin and acid generators. Particularly effective in this embodiment is a resist having a viscosity of less than 10 mPa's and an average molecular weight of less than 100,000. In addition, in the case of a resist composed of a plurality of constituent materials including a polymer (Polymer), a PAG (Photo Acid Generator), and a Quencher, such as a chemically amplified resist, the above-mentioned constituent materials are included in the mask blank surface. Due to the in-plane variation, the effect of the present invention is most obtained in a resist material in which in-plane CD variation is likely to occur.

[0037] The number of rotations and the rotation time of the thin film-coated substrate 15 in the homogenization step and the drying step are the forces set according to the type of the resist solution 26, as shown in FIG. The rotational speed of the substrate with thin film 15 is set higher than the rotational speed of the substrate with thin film 15 in the drying process. From this, it is possible to form a resist film 16 having a uniform thickness even in the mask pattern formation region 17 that extends to the outer region of the inscribed circle 27 (Fig. 3) on the substrate 15 with a rectangular thin film. It becomes. [0038] For example, a chemically amplified resist novolac resist has a low viscosity (lOmPa • s or less), so in the homogenization process, the substrate rotation speed is 850 to 2000 rpm and the substrate rotation time is 1 to 10 seconds. In the drying process, the substrate rotation speed is set to 100 to 450 rpm. In addition, since the viscosity of polymer resist is high (more than lOmPa's), the substrate rotation speed is set to 850 to 2000 rpm and the substrate rotation time is set to 2 to 15 seconds in the homogenization process. The substrate rotation speed is set to 50 to 450 rpm. The substrate rotation time in the drying process is set to a time required until the resist film 16 is completely dried (until the film thickness of the resist film 16 does not decrease even if the drying rotation is continued further).

[0039] In the resist coating step, after completion of the drying step, the resist film 16 is heated and dried to completely evaporate the solvent contained in the resist film 16 formed on the thin film-coated substrate 15. You may have the heat drying process process to do. This heating and drying process is usually performed by a heating process in which the thin film-coated substrate 15 on which the resist film 16 is formed is heated by a heating plate, and a cooling process in which the thin film-coated substrate 15 in which the resist film 16 is formed is cooled by a cooling plate. Process. The heating temperature and time in these heating steps and the cooling temperature and time in the cooling step are appropriately adjusted according to the type of the resist solution 26.

[0040] By the way, as shown in FIG. 1, the dropping step performed before the above-described homogenization step is performed by applying a predetermined amount of resist solution 26 for obtaining a required film thickness from a nozzle 22 to a substrate with a thin film. In this step, the resist solution 26 is spread and spread on the surface 19 of the substrate 15 with a thin film. More specifically, when a predetermined amount of resist liquid 26 for obtaining a required film thickness is dropped from the nozzle 22 onto the surface 19, the distance of the substrate rotation center 0 force below the resist droplet position (the eccentric position Q, Adjusting the relative movement speed of the substrate 15 and the nozzle 22 (rotation speed of the substrate 15 when the position of the nozzle 22 is fixed) and drawing a donut-shaped drop locus C (see Fig. 5) (See A)), start dripping (dropping start part 16a) and drop the resist solution 26 in the shape of a ball until the end of dripping (see Fig. 5 (B)), then spread this ball-shaped resist solution 16b and spread the substrate This is a process of forming a substantially circular resist reservoir 16c near the center (see FIG. 5C).

Specifically, the thin film resist 15 is rotated by the motor 25 via the spinner chuck 21, and a predetermined distance from the center 0 (see FIG. 3) of the surface 19 of the thin film resist 15 is obtained. The nozzle 22 is set at the eccentric position Q, and the resist solution 26 is dropped from the nozzle 22 while the thin film substrate 15 is rotating, so that it is symmetrical with respect to the center O of the surface 19 of the thin film substrate 15. Then, the resist solution 26 is dropped in a ball shape while drawing a donut-like trajectory, and this changes the dropping position of the resist solution 16 with respect to the surface 19 of the substrate 15 with a thin film, thereby The resist solution 26 can be dispersed and dropped on the surface 19.

[0041] While the substrate 15 with a thin film is stationary, the nozzle 22 is rotated around the center O of the surface 19 of the substrate 15 with a thin film, and the resist solution 26 is supplied from the nozzle 22 to the surface 19 of the substrate 15 with a thin film. The resist solution 26 may be dropped in a ball shape while drawing a donut-like locus at a position symmetrical to the center O of the surface 19 of the surface 19 of the substrate 15 with a thin film.

[0042] In this dropping step, the number of rotations when the thin film-coated substrate 15 is rotated is set by appropriately adjusting the force such as the final discharge amount and discharge speed of the resist solution 26 and the dropping position of the resist solution 26. For example, 0.5 to 50 rpm is preferable, and 5 to 25 rpm is more preferable. In addition, the dropping position of the resist solution 26 is preferably such that the distance (eccentric position Q) from the substrate rotation center 0 at the position below the resist droplet is 1 cm or more and 5 cm or less.

If the rotation speed exceeds 50 rpm, the number of rotations of the thin film-coated substrate 15 is too large, and the resist solution 26 dripped may scatter or the resist solution 26 may not spread at the center O of the surface 19 of the thin film-coated substrate 15. As a result, the resist film 16 having a uniform thickness may not be formed.

If the rotational speed is less than 0.5 rpm, the amount of the resist solution 26 used may increase, or the resist solution 26 may enter the back side of the thin film-coated substrate 15 and cause particles. Also, if it is less than 0.5 rpm, the effect of suppressing the high sensitivity of the resist is smaller than the position below the resist droplet and other positions. Therefore, the rotation speed of the thin film-attached substrate 15 in the dropping step is set in the range of 0.5 to 50 rpm.

[0043] Further, in the dropping step, in the case where the resist solution 26 is dropped in a ball shape while drawing a donut-shaped dropping locus at a position symmetrical to the center O of the surface 19 of the substrate 15 with a thin film, In the homogenization process, the resist solution 26 is spread evenly over the entire surface 19 of the substrate 15 with a thin film to form a resist film 16 having a uniform thickness (good in-plane film thickness uniformity). Includes the step of spreading the resist solution 26 to the center O position of the surface 19 of the substrate 15 There is a need. This process stops the rotation of the substrate 15 with the thin film after the completion of the dropping of the resist solution 26 from the nozzle 22 and draws a donut-shaped dropping trajectory around the center O of the surface 19 of the substrate 15 with this thin film. This is a process of waiting until the resist solution 26 dropped and formed in the ball-shaped resist solution 16b spreads to the center O position of the surface 19.

[0044] Further, the step of spreading the resist solution 26 to the center O position of the surface 19 of the substrate 15 with a thin film is performed by rotating the nozzle 22 set above the surface 19 of the substrate 15 with a thin film during the rotation of the substrate 15 with a thin film. Can also be realized in the dropping step of moving on the surface 19 of the substrate with thin film 15 on the straight line L passing through the center O and the eccentric position Q, and the following two dropping steps can be mentioned.

[0045] In the first dropping step, a nozzle 22 that drops the resist solution 26 and is set at an eccentric position Q of the surface 19 of the substrate 15 with a thin film while the substrate 15 with a thin film rotates is placed on the straight line L. In this case, it is moved in the center O direction. The resist solution 26 to which the nozzle 22 force set at the eccentric position Q is also dropped is dropped in a slanting shape while drawing a dropping locus around the center O of the surface 19 on the surface 19 of the rotating thin film-coated substrate 15. However, as the nozzle 22 moves in the direction of the center O as described above, the resist solution 26 dropped from the moving nozzle 22 moves closer to the center O on the surface 19 of the rotating thin film-coated substrate 15. Will be dripped. As a result, the resist liquid 26 dropped on the surface 19 of the substrate 15 with a thin film can be quickly spread to the center O position of the surface 19.

[0046] In the second dropping step, the nozzle 22 set at the center 0 of the surface 19 of the substrate 15 with a thin film or the eccentric position Q slightly deviated from the center O is moved up while the substrate 15 with a thin film is rotating. The resist liquid 26 is dropped from the nozzle 22 while being gradually moved to the outside of the substrate 15 with a thin film on the straight line L. In this dropping step, the initial nozzle 22 of the dropping step is dropped at or near the center O of the surface 19 of the rotating thin film-coated substrate 15, so that the resist solution 26 reaches the position of the center O of the surface 19 of the thin film-coated substrate 15. The resist solution 26 is dropped in the direction in which the centrifugal force acts on the surface 19 of the substrate 15 with a thin film, so that the resist solution 26 is applied to the surface 19 of the substrate 15 with a thin film. It can be spread quickly and uniformly outward.

[0047] By carrying out the dropping step, the homogenizing step and the drying step as described above, the substrate with a thin film A resist film 16 is formed on the surface 19 of the thin film 14 of the plate 15 to produce a mask blank 10 shown in FIG. Then, a predetermined pattern is drawn on the resist film 16 of the mask blank 10 and developed to form a resist pattern, and the thin film 14 (for example, a light shielding film) is dry-etched using the resist pattern as a mask to mask pattern 13 (FIG. 4 (B)) is formed, and an exposure mask 18 is produced.

Therefore, according to the said embodiment, there exist the following effects (1)-(5).

(1) In the dropping step in the resist coating process, the resist solution 26 is dropped from the nozzle 22 to the eccentric position Q that is eccentric with respect to the center O of the surface 19 of the surface 15 of the substrate with thin film 15 while rotating the substrate 15 with thin film. Then, the dropping position of a predetermined amount of resist solution 26 for obtaining the required film thickness is changed on the surface 19 of the thin film substrate 15, and this resist solution 26 is dispersed and dropped on the surface 19 of the substrate 15 with thin film. Will be. Therefore, the predetermined amount of resist solution 26 is not concentrated and dropped at one place on the surface 19 of the substrate 15 with a thin film (for example, concentrated at the center O position of the surface 19). In the exposure mask 18 having the mask pattern 13 formed by using the resist pattern formed from the resist film 16 as a mask, the pattern line of the mask pattern 13 can be prevented. It is possible to suppress the “in-plane CD variation” in which the line width dimension (CD) of 28 (Fig. 4 (B)) varies within the plane with respect to the target target line width dimension (CD). As a result, it is possible to realize an exposure mask 18 that can meet the demand for pattern miniaturization of a transfer target (for example, a half pitch 65 nm node in a semiconductor device).

(2) When the resist solution 26 is dropped on the substrate surface 19, the resist solution 26 is dropped in a ball shape so that the dropping position of the resist solution 26 on the substrate surface 19 is different. The nozzles 22 for dropping the substrate 15 and the resist solution 26 are moved relative to each other so that the positions of the substrate 15 and the resist solution 26 drop over time. Since the resist solution 22 was dropped by adjusting the distance of the center of rotation O force from 1 cm to 5 cm and adjusting the number of rotations of the substrate from 0.5 rpm to 50 rpm, the resist solution 22 was applied to the substrate surface 19. It is possible to prevent the concentration of the components constituting the resist solution affecting the resist sensitivity from concentrating on the position of the dropping position. Therefore, the mask blank resist film 16 produced by the above manufacturing method 16 In the exposure mask 18 having the mask pattern 13 formed by using the resist pattern formed by the exposure / development process as a mask, the resist solution 26 is dropped at and near the dropping position of the resist solution 26 and other positions. The line width dimension (CD) of the mask pattern pattern line 28 (Fig. 4 (B)) due to variations in film sensitivity varies in-plane with respect to the target line width dimension (CD) of the target line. CD variation can be suppressed. As a result, it is possible to realize an exposure mask 18 that can meet the demand for pattern miniaturization of a transfer target (for example, a generation after a half pitch 65 nm node in a semiconductor device).

[0049] (3) Since the dropping step in the resist coating step includes the step of spreading the resist solution 26 dropped on the surface 19 of the substrate 15 with a thin film to the center O position of the surface 19, the substrate 15 with a thin film is formed. In the rotating homogenization step, the resist solution 26 can be spread uniformly over the entire surface 19 of the substrate 15 with a thin film, so that the resist film 16 having a uniform film thickness can be formed.

[0050] (4) In the dropping step in the resist coating step, a nozzle 22 for dropping the resist solution at the eccentric position Q where the center O force of the surface 19 of the substrate 15 with the thin film is also eccentric during the rotation of the substrate 15 with the thin film is used. When moving in the direction of the center O on the straight line L passing through the center O and the eccentric position Q of the surface 19 immediately before the completion of dropping, the resist solution 26 dropped on the surface 19 of the substrate 15 with a thin film Can be quickly expanded to the center O position of surface 19.

[0051] (5) In the dropping step in the resist coating step, the nozzle 22 for dropping the resist solution on the center O of the surface 19 of the substrate 15 with a thin film or the eccentric position Q eccentric from the center O is provided with the thin film In the case of moving outward on a straight line L passing through the center O of the surface 19 and the eccentric position Q during the rotation of the substrate 15 with the surface, the resist solution 26 dropped on the surface 19 of the substrate 15 with the thin film is added to this. The resist solution 26 dripped onto the surface 19 can be spread quickly and uniformly outward on the surface 19 of the substrate 15 with a thin film.

(6) The dropping position of a predetermined amount of the resist solution 26 for obtaining the required film thickness is changed on the surface 19 of the substrate 15 with a thin film, and the resist solution 26 is applied to the surface 19 of the substrate 15 with a thin film. Since the resist solution 26 is a chemically amplified resist that has a low viscosity and is easily dried, the trace of the dripping of the resist solution 26 is generated on the surface 19 of the substrate 15 with a thin film. Chemical amplification type at the dripping position, its vicinity and other positions Concentration of the components constituting the resist solution that affects the resist sensitivity of the resist at the dropping position can be suppressed. Therefore, in-plane CD variation in the mask pattern 13 of the exposure mask 18 due to variation in sensitivity of the resist film 16 in the mask blank can be suppressed. Example

Next, a method for manufacturing a mask blank and a method for manufacturing an exposure mask will be specifically described.

[Example 1]

A thin film substrate in which a chromium film and a chromium oxynitride film are sequentially formed on a synthetic quartz glass substrate having a size of 152.4 mm x 152.4 mm by a sputtering method, and a thin film of a light shielding film and an antireflection film is formed. Obtained.

Next, a resist solution was spin-coated by a resist coating process to form a resist film on the surface of the thin film. Each condition in the resist coating process is as follows.

Resist: Positive chemically amplified resist FEP171 (Fuji Film Elect Mouth-Cusmaterials)

Dropping step: The resist solution was dropped while rotating the substrate with the thin film.

Board rotation speed: 5rpm

Resist dropping method on the substrate: The resist solution was dropped at an eccentric position 3 cm eccentric from the center of the surface of the substrate with the thin film, and after the substrate was rotated at least once, the dropping of the resist solution was terminated. The resist solution was dropped onto the substrate by appropriately adjusting the discharge speed of the resist solution from the nozzle so that the dripping start force was dropped until the completion of dropping while drawing the dropping locus in a donut shape. After completion of the dropping of the resist solution, the resist solution dropped on the surface of the substrate with the thin film was kept waiting until it spreads to the center position of the substrate with the thin film. During this waiting time, the resist solution spreads in the same way as the center direction in the outer peripheral direction of the substrate with the thin film as well as the dropping position. That is, a substantially circular resist pool was formed near the center of the substrate surface (near the center).

Uniformization process

Board rotation speed: 1500rpm

Substrate rotation time: 2 seconds Drying process

Substrate rotation speed: 250rpm

Next, the substrate with the thin film on which the resist film was formed was transported to a heating / drying device and a cooling device, and a predetermined heating / drying process was performed to dry the resist film, thereby producing a mask blank for ArF excimer laser exposure. .

[0055] The film thickness distribution of the obtained mask blank resist film was measured. As a result, the average thickness of the resist film was 300 nm, and the in-plane film thickness uniformity of the resist film was 3 nm.

Here, the film thickness distribution of the resist film, the surface center of the thin-film-coated substrate 132 mm X 132 m _m square area (i.e., a mask pattern formation region) at the measurement point of the uniformly arranged on the entire 29 X 29 = 841 The film thickness was measured using a spectral reflection type film thickness meter manufactured by Nometrics Japan Co., Ltd. (AFT6100M), and the measured film thickness data power also determined the average film thickness. The in-plane film thickness uniformity was obtained as the film thickness data force “(maximum value of film thickness) (minimum value of film thickness) = (in-plane film thickness uniformity)” at each measurement point.

Next, a predetermined pattern was drawn on the resist film by an electron beam drawing apparatus, and a resist pattern was formed by heat treatment and development treatment. Using this resist pattern as a mask, dry etching treatment was performed using a gas containing chlorine and oxygen to form a mask pattern (light-shielding film pattern), and the resist film was peeled off to produce an exposure mask. The mask pattern of the obtained exposure mask is a line and space pattern, and the line width dimension (CD) of the pattern line is 260 nm.

The line width dimension of this mask pattern, which is 13 X 13 in the exposure mask plane, is measured with the SEM, and the line width dimension (CD) of the pattern line in the mask pattern of the exposure mask is “In-plane CD variation”, which varies within the plane of the mask, was measured. As a result, in-plane CD variation of 4 nm was achieved at 3 σ, which is a demand for next-generation semiconductor device pattern miniaturization (norf pitch 65 nm node) 5. lnm (in the case of line and space no-turn) ) Was satisfied.

[0057] (Comparative example)

A mask blank was prepared in the same manner as in Example 1 except that the dropping process of the resist coating process in Example 1 was changed to the following method. A disc was prepared.

Dropping step: Without rotating the substrate with a thin film, a predetermined amount of resist solution was dropped at the center position of the surface of the substrate with a thin film to obtain a required film thickness.

The average film thickness and in-plane film thickness uniformity of the resist film in the obtained mask blank were almost the same as those in Example 1.

Also, the in-plane CD variation (3σ) of the exposure mask produced with this mask blank force was 7 nm. This in-plane CD variation (3 σ) of 7 nm did not satisfy 5. lnm (in the case of a line and space pattern), which is a demand for pattern miniaturization of semiconductor devices in the next generation (node pitch 65 nm node). .

The resist film surfaces formed in the mask blank with resist film in Example 1 and the mask blank with resist film in Comparative Example 1 are analyzed with TOF SIMS (time-of-flight secondary ion mass spectrometry) at the center and outer periphery of the substrate. It was measured by. As a result, the concentration of the PAG component on the resist film surface in Example 1 was almost the same in the central portion and the outer peripheral portion, but the concentration of the PAG component in Comparative Example 1 was more in the outer peripheral portion than in the central portion. The trend was low.

This is because the chemically amplified resist formed in the mask blank of Example 1 is uniformly contained in the surface of the mask blank, which is the constituent material force of the polymer, PAG and quencher constituting the chemically amplified resist. Force The chemically amplified resist formed in the mask blank of Comparative Example 1 is the only polymer, PAG, and quencher constituent material in the chemically amplified resist. It is thought that the difference appears in the difference in in-plane CD variation.

(Example 2)

The resist solution in Example 1 was changed to the negative chemical amplification resist NEB22 (manufactured by Sumitomo Chemical Co., Ltd.). In the resist coating process, the substrate rotation speed was set to 800 rpm and the substrate rotation time was set to 4 in the homogenization process. A mask blank was prepared in the same manner as in Example 1 except that the substrate rotation speed was set to 300 rpm in the drying process. From this mask blank, the mask pattern was an isolated line pattern, and the line width of the pattern line An exposure mask with dimensional (CD) force of l80nm was fabricated. The average film thickness and in-plane film thickness uniformity of the resist film in the obtained mask blank were almost the same as those in Example 1. The in-plane CD variation (3σ) of the obtained exposure mask was 2 nm. This in-plane CD variation (3 σ) of 2 nm was able to satisfy 3.6 nm (in the case of an isolated line pattern), which is a request for pattern miniaturization of semiconductor devices in the next generation (node pitch 65 nm node). This is thought to be due to the fact that the polymer, PAG, and Quencher's constituent materials that make up the chemically amplified resist are uniformly contained in the mask blank surface.

(Comparative Example 2)

The resist dropping method onto the substrate is adjusted to the position of dropping the resist solution and the number of rotations of the substrate as appropriate, as described in Patent Document 2, and the dropping of the resist solution onto the substrate is dropped into a donut shape. A mask blank was prepared in the same manner as in Example 1 except that a resist reservoir was immediately formed near the center of the substrate without going through the process, and an exposure mask was also prepared with this mask blank force.

Further, the in-plane CD variation (3σ) of the exposure mask produced with this mask blank force was 6.8 nm. This in-plane CD variation (3 σ) 6.8 nm does not satisfy the demand for next-generation semiconductor device pattern miniaturization (norf pitch 65 nm node) 5. lnm (in the case of a line-and-space pattern). It ’s nasty. The polymer, PAG, and quencher constituent materials that make up the chemically amplified resist with a high resist solution pressure on the substrate under the resist droplets are not evenly contained in the mask blank surface and vary. Having one of these is considered to be one factor.

(Examples 3 to 4)

A mask blank was produced in the same manner as in Example 1 except that the resist dropping position was set to 1 cm (Example 3) and 5 cm (Example 4) from the center of the surface of the substrate with the thin film. This mask blank force exposure mask was produced.

The average film thickness and in-plane film thickness uniformity of the resist film in the obtained mask blank were almost the same as those in Example 1. The in-plane CD variation (3 σ) of the exposure mask produced with this mask blank force was 5 nm (Example 3) and 4.7 nm (Example 4). This in-plane CD variation (3 σ) satisfied 5. lnm (in the case of a line and space pattern), which is a demand for pattern miniaturization of semiconductor devices in the next generation (a node pitch of 65 nm).

(Examples 5 to 6)

In Example 4 above, the number of rotations of the substrate at the time of dropping the resist was 0.5 rpm (Example 5), and in Example 3 above, the number of rotations of the substrate at the time of dropping the resist was 50 rpm (Example 6). A mask blank was produced in the same manner as in Examples 3 and 4, and an exposure mask was produced with this mask blank force.

The in-plane CD variation (3σ) of the exposure mask produced with this mask blank force was 4.8 nm (Example 5) and 5 nm (Example 6). This in-plane CD variation (3 σ) satisfied 5. lnm (in the case of a line and space pattern), which is a demand for pattern miniaturization of semiconductor devices in the next generation (a node pitch of 65 nm).

In the case where the resist solution is dropped under the conditions deviating from the optimum resist dropping conditions in the present invention (distance from the substrate rotation center of 1 cm to 5 cm and substrate rotation speed of 0.5 rpm to 50 rpm), In-plane CD variation may occur to meet the demands for next-generation semiconductor device pattern miniaturization (node pitch: 65nm node), and resists with a uniform film thickness do not reach the substrate rotation center. When a film is not formed and something happens!

Although the present invention has been described based on the above embodiment, the present invention is not limited to this. For example, the nozzle 22 used in the dropping step of the resist coating step is formed in a ring shape or a horseshoe shape that can drop the resist solution 26 at a plurality of positions symmetrical to the center O of the surface 19 of the substrate 15 with a thin film. Then, the resist solution 26 may be dispersed and dropped at a plurality of locations on the surface 19 of the substrate 15 with a thin film. In addition, in the dropping step in the resist coating process, the substrate rotation speed is not set to a constant rotation speed, but is changed continuously or stepwise from a low rotation speed to a high rotation speed or a high rotation speed force from a low rotation speed. Also Good.

Brief Description of Drawings

FIG. 1 is a side cross-sectional view showing a spin coating apparatus for performing a resist coating process in an embodiment of a mask blank manufacturing method according to the present invention.

2 is a graph showing the relationship between the number of rotations of a substrate and the rotation time in a resist coating process using the spin coater of FIG.

FIG. 3 is a plan view showing the thin film-coated substrate of FIG.

[FIG. 4] (A) is a sectional view showing a mask blank in which the substrate force with a thin film of FIG. 1 is also manufactured, and (B) is an exposure mask in which the mask blank force of FIG. 4 (A) is also manufactured. It is a sectional view

FIG. 5 is a plan view showing a state of the resist solution dripping on the substrate surface in the dropping step in the mask blank manufacturing method according to the present invention, in which (A) shows the resist solution at the start of the dropping of the resist solution. FIG. 5B is a plan view showing a dropping state and a dropping trajectory of the resist solution, and FIG. 5B is a plan view showing a dropping state of the resist solution at the time when the resist liquid is dropped after the completion of dropping. (C) is a plan view showing a state in which a resist pool is formed in the vicinity of the center of the substrate after the resist solution has been dropped onto the substrate surface.

Explanation of symbols

[0061] 10 mask blank

11 Board

13 Mask pattern

14 Thin film

15 Substrate with thin film

16 Resist film

16b Jade-shaped resist solution

18 Exposure mask

19 Surface

20 spin coater 26 Resist solution O center Q Eccentric position

Claims

The scope of the claims

[1] Nozzle force When the resist solution is dropped onto the substrate surface, the resist solution is dropped onto the surface of the substrate so that the resist solution drops at different positions, and then the dropped resist solution is spread to center the substrate. A method for manufacturing a mask blank, comprising: forming a resist pool in the vicinity, diffusing the resist pool to a peripheral portion of the substrate surface by centrifugal force, and then drying to form a resist film.

[2] The mask blank according to claim 1, wherein the substrate and the nozzle for dropping the resist solution are relatively moved so that the dropping position of the resist solution becomes a different position as time passes. Manufacturing method.

[3] When the resist solution is dropped onto the substrate surface from the nozzle cover, the resist solution is dropped in the shape of a slant by adjusting the distance from the substrate rotation center below the resist droplet and the relative movement speed of the substrate and the nozzle. The method for producing a mask blank according to claim 1 or 2, wherein:

[4] When the resist solution is dropped onto the substrate surface, the nozzle force is also positioned below the resist droplet so that the resist solution is less sensitive to the position where the resist solution is dropped onto the substrate surface than at other locations. Adjust the distance of the substrate rotation central force and the number of rotations of the substrate within the following range, drop the resist solution, spread the dropped resist solution to form a resist pool near the center of the substrate, A resist blank is formed by diffusing the resist pool to the periphery of the substrate surface by centrifugal force, and then drying to form a resist film.

Distance from the substrate rotation center under the resist droplet: lcm or more and 5cm or less

Board rotation speed: 0.5rpm or more and 50rpm or less

[5] A mask blank manufacturing method comprising a resist coating step of forming a resist film by coating a resist solution on a rectangular substrate,

The resist coating process

A dropping step in which a resist solution is dropped on the surface of the substrate and spread;

A uniformizing step of uniformly spreading the dropped resist solution over the entire surface of the substrate to form a resist film having a uniform thickness;

A drying step of drying the resist film formed in a uniform film thickness,

In the dropping step, a predetermined amount or more of a resist solution that gives the required film thickness is dropped from the nozzle cover. When the resist solution is dropped onto the substrate surface, the distance from the substrate rotation center at the position below the resist droplet and the number of rotations of the substrate so that the sensitivity of the resist is suppressed compared with other positions. Is adjusted within the following range, and a resist solution is dispersed and dropped on the surface of the substrate.

Board rotation speed: 0.5rpm or more and 50rpm or less

[6] The mask blank manufacturing method according to any one of [1] to [5], wherein the resist solution is made of a chemically amplified resist.

7. The method for manufacturing a mask blank according to any one of claims 1 to 6, wherein the substrate is a substrate with a thin film in which a thin film serving as a mask pattern is formed on the substrate.

8. The method of manufacturing a mask blank according to claim 7, wherein the thin film has a material force including chromium.

[9] A resist pattern of the master blank manufactured by the mask blank manufacturing method according to any one of claims 1 to 8 is patterned to form a resist pattern, and the mask pattern is formed using the resist pattern as a mask. An exposure mask manufacturing method characterized by forming an exposure mask.