JP2007058200A - Mask blank manufacturing method and exposure mask manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress in-plane CD variation or the like in a mask pattern of an exposure mask based on a difference in sensitivity between the vicinity of the center and the periphery of a mask blank so that it can be adapted to a half pitch 65 nm node in a semiconductor device, for example.
When a resist solution is dropped from the nozzle onto the surface of the substrate, the position below the resist droplet is controlled so that the sensitivity of the resist is suppressed compared to other positions at the position where the resist solution is dropped onto the substrate surface. The resist solution is dropped by adjusting the eccentric position Q from the substrate rotation center of the substrate and the rotation speed of the substrate within the following range, and the dropped resist solution is spread to form a resist pool near the center of the substrate. The pool is diffused to the periphery of the substrate surface by centrifugal force, and then dried to form a resist film.
[Selection] Figure 1

Description

  The present invention provides a mask blank manufacturing method having a resist coating process in which a resist solution is uniformly spin-coated on a rectangular substrate and a resist film is formed in which in-plane variation of resist sensitivity is suppressed, and from this mask blank More particularly, the present invention relates to a method for manufacturing a mask blank for manufacturing a semiconductor device and a method for manufacturing an exposure mask for manufacturing a semiconductor device.

  Conventionally, when a resist film is formed on a rectangular substrate or a thin film-coated substrate having a thin film formed on the substrate, the resist is rotated using a spin coater that rotates the substrate and applies a resist solution. A coating method 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 the four corners of the substrate is known.

In this resist spin coating method, the product of the number of rotations of the substrate and the rotation time is selected to be, for example, 24000 (rpm · sec) or less, and the rotation time is selected to be 20 seconds or less, whereby the substrate rotation number and After the substrate rotation time is set and the resist solution is dropped on the substrate, the substrate is rotated for the substrate rotation time at the substrate rotation speed set as described above, and a uniform process is performed to uniformize the resist film thickness. And then drying the resist film while rotating the substrate at a rotation speed lower than the rotation speed of the substrate in the homogenization process and maintaining the uniformity of the film thickness of the resist film obtained in the homogenization process. The process is performed.
As a uniform resist coating method for preventing uneven coating of the resist solution, a 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.
Japanese Patent Publication No. 4-29215 Japanese Patent Laid-Open No. 57-130570

  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. The focal length of lenses used in the apparatus is also shortening. Furthermore, in the mask for exposure used in the photolithography technology and the mask blank for manufacturing the mask for exposure, the light shielding film for shielding the light with respect to the exposure wavelength of the exposure light and the phase shift for shifting the phase. Membrane development has been carried out rapidly, and various membrane materials have been proposed.

Since such a trend of innovation in photolithography technology will continue, the accuracy required for exposure masks and mask blanks is becoming stricter year by year. For example, in a half pitch 65 nm node, which is a demand for pattern miniaturization of a semiconductor device as a transfer target, the line width dimension (CD: Critical Dimension) of the pattern line in the mask pattern of the exposure mask is the target target line. The “in-plane CD variation”, which varies in-plane with respect to the line width dimension (CD), is 5.1 nm for the line and space pattern and 3.6 nm for the isolated line pattern. The achievement of mask manufacturing technology is becoming difficult.
Factors resulting from “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-bake processing temperature after forming the resist film. Sex and so on. Further, factors resulting from “in-plane CD variation” in the manufacturing process of the exposure mask include in-plane uniformity of post-exposure bake processing temperature, in-plane uniformity of development processing, and the like.
Note that the above-mentioned “in-plane CD variation” is obtained by drawing a line on a resist film using a test pattern for in-plane uniformity evaluation, forming a resist pattern by processing, and then measuring a line such as a SEM for length measurement. Using a width dimension measuring device, pattern dimensions are measured and evaluated at a plurality of predetermined locations in the plane from the center of the substrate to the outer periphery.

Even when the in-plane uniformity in the mask blank manufacturing process and the exposure mask manufacturing process due to the “in-plane CD variation” is improved, the “in-plane CD variation” is not improved. In particular, in recent years, in order to make semiconductor device patterns finer, it is necessary to increase the sensitivity and resolution of resist films, so that chemically amplified resist films that meet these requirements are used. The problem became noticeable.
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 was 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 the sensitivity was under, that is, the sensitivity was lowered.
This is because a chemically amplified resist is generally composed of a polymer, a PAG (Photo Acid Generator), and a Quencher. When a chemically amplified resist is formed on a mask blank, When the chemically amplified resist solution is dropped on the substrate, even if the substrate rotates, a situation occurs in which certain components tend to stay near the center, and the resist film structure is formed near the center of the mask blank and at the outer periphery. Variation in the amount of material occurs, which causes sensitivity variations near the center of the substrate and the outer periphery of the mask blank surface, affecting the CD variation in the mask blank surface, and pattern fineness of the transferred object. I found out that it was difficult to respond to the request for conversion.

  The object of the present invention has been made in consideration of the above-described circumstances, and suppresses in-plane CD variation in the mask pattern of the exposure mask based on the difference in sensitivity between the vicinity of the center of the mask blank and the vicinity of the outer periphery. A mask blank manufacturing method capable of realizing an exposure mask capable of meeting a request for pattern miniaturization of a transfer body, for example, a request for adapting to a half pitch 65 nm node in a semiconductor device, and exposure using the mask blank An object of the present invention is to provide a method for manufacturing an exposure mask for manufacturing a mask for use.

As means for solving the above problems,
In the mask blank manufacturing method according to the first means, when the resist solution is dropped onto the substrate surface, the resist solution dropped on the substrate surface is dropped in a ball shape so that the dropping position of the resist solution on the substrate surface is different. The resist is spread to form a resist pool in the vicinity of the center of the substrate, the resist pool is diffused to the peripheral portion of the substrate surface by centrifugal force, and then dried to form a resist film.
The mask blank manufacturing method according to the second means is the first means in which the substrate and the nozzle for dropping the resist solution are relatively positioned so that the dropping position of the resist solution is different with time. It is made to move to.
The mask blank manufacturing method according to the third means is the first or second means in which when the resist solution is dropped from the nozzle onto the substrate surface, the distance from the substrate rotation center at the position below the resist droplet, the substrate and the nozzle The resist solution is dripped in the shape of a slanted ball by adjusting the relative movement speed of the lens.
In the mask blank manufacturing method according to the fourth means, when the resist solution is dropped from the nozzle onto the substrate surface, the resist solution is prevented from increasing in sensitivity at the position where the resist solution is dropped onto the substrate surface as compared with other positions. In addition, the resist solution is dropped by adjusting the distance from the substrate rotation center below the resist droplet and the rotation speed of the substrate within the following ranges, and the dropped resist solution is spread to form a resist pool near the center of the substrate. The resist pool is formed and 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.
The mask blank manufacturing method according to the fifth means is a mask blank manufacturing method having a resist coating step of forming a resist film by applying a resist solution on a rectangular substrate, and the resist coating step includes: A dropping step of dropping and spreading a resist solution on the surface of the substrate; 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; and A drying step of drying the resist film formed in a film thickness, and the dropping step drops the resist solution on the substrate surface when a predetermined amount or more of resist solution is obtained from the nozzle to obtain a required film thickness. Adjust the distance from the substrate rotation center at the position below the resist droplet and the number of rotations of the substrate in the following ranges so that the sensitivity of the resist is suppressed at other positions compared to other positions. It is characterized in that the dripping dispersed resist liquid to the surface of the.
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.

The mask blank manufacturing method according to 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.
The mask blank manufacturing method according to the seventh means is the fifth or sixth means, wherein the dropping step comprises applying a resist solution of a predetermined amount or more that can obtain a required film thickness from the nozzle to the surface of the substrate. When dripping, the dripping position is changed.

  In the mask blank manufacturing method according to the eighth means, in any one of the first to seventh means, the dropping of the resist solution moves the nozzle while rotating the substrate or around the center of the surface of the substrate. The resist solution is dropped at a position eccentric with respect to the center of the substrate surface.

  In the mask blank manufacturing method according to the ninth means, in any one of the first to eighth means, the dropping of the resist solution includes a step of spreading the resist solution dropped on the surface of the substrate to the center of the surface. It is characterized by including.

  The mask blank manufacturing method according to the tenth means is the ninth means, wherein the step of spreading the resist solution to the center of the surface of the substrate in dropping the resist solution is the completion of dropping the resist solution dropped on the surface. It is a process which waits until it spreads to the center of the said surface later, It is characterized by the above-mentioned.

  According to an eleventh means for manufacturing a mask blank, in the eighth or ninth means, in the dropping step, the nozzle for dropping the resist solution is rotated on a straight line passing through the center of the surface during rotation of the substrate. And moving to an eccentric position from the center of the surface of the substrate.

  According to a twelfth means for producing a mask blank, in the eleventh means, in the dropping step, a nozzle for dropping the resist solution is rotated on the substrate surface on a straight line passing through the center of the surface. This is characterized in that the substrate is moved from the eccentric position toward the center of the substrate surface.

  A mask blank manufacturing method according to a thirteenth means is the nozzle according to the eleventh means, wherein the dropping step drops the resist solution at the center of the surface of the substrate or a position eccentric from the center during the rotation of the substrate. Is moved outward on a straight line passing through the center of the surface.

  A fourteenth means for producing a mask blank is characterized in that, in any one of the first to thirteenth means, the resist solution is made of a chemically amplified resist.

In a mask blank manufacturing method according to a fifteenth aspect, 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. Is.
According to a sixteenth means, the mask blank manufacturing method of the fifteenth means is characterized in that the thin film is made of a material containing chromium.

  The exposure mask manufacturing method according to the seventeenth means comprises forming a resist pattern by patterning the resist film of the mask blank manufactured by the mask blank manufacturing method according to any one of the first to sixteenth means. The exposure mask is manufactured by forming a mask pattern using the resist pattern as a mask.

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 so that the dropping position of the resist solution on the substrate surface is different. The substrate and the resist solution dropping nozzle are moved relative to each other so that the dropping position becomes different as time passes, so that it drops like a slant, and more specifically, the substrate rotation at the position below the resist droplet The resist solution is dropped by adjusting the distance from the center to 1 cm or more and 5 cm or less and the rotation speed of the substrate 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 possible to suppress the components of the resist solution affecting the resist sensitivity from being concentrated at the dropping position. It is a thing. Accordingly, in an exposure mask having a mask pattern formed using a resist pattern formed by exposure / development processing on a resist film of a mask blank produced by the above manufacturing method as a mask, the dropping position of the resist solution and In the vicinity and other positions, the “in-plane CD variation” in which the line width dimension (CD) of the pattern line of the mask pattern due to the sensitivity variation of the resist film varies in the plane can be suppressed. As a result, it is possible to realize an exposure mask that can meet a demand for pattern miniaturization of a transfer target (for example, a generation after a half pitch 65 nm node in a semiconductor device). Although the mechanism by which the “in-plane CD variation” is suppressed by the resist solution dropping method is not clear, the conditions under which the resist solution is dripped onto the substrate surface are such that the pressure of the resist solution on the substrate surface is weak, and A resist pool can be formed in the vicinity of the center of the substrate while the resist solution gently spreads on the substrate surface from the start of dropping of the resist solution to the end of dropping. In other words, due to the weak pressure of the resist solution against the substrate surface when it is under the resist droplet, the components that make up the resist solution that affects the resist sensitivity remain at the dropping position on the substrate surface due to the surface condition of the substrate surface, etc. It is considered that the in-plane CD variation is suppressed when the components constituting the resist solution that affects the resist sensitivity are uniformly dispersed on the substrate surface.
According to the fifth and fifteenth means, in the dropping step in the resist coating step, a predetermined amount or more of a resist solution that obtains a required film thickness is dispersed and dropped on the surface of the substrate. Since the resist solution is not concentrated and dripped at one place on the surface of the substrate, it is possible to prevent the occurrence of dripping marks on the surface of the substrate and to form the resist pattern formed from the resist film as a mask. In the exposure mask having the mask pattern, the “in-plane CD variation” in which the line width dimension (CD) of the pattern line of the mask pattern varies in the plane can be suppressed. As a result, it is possible to realize an exposure mask that can meet the demand for pattern miniaturization of the transfer target (for example, a half pitch 65 nm node in a semiconductor device).

  According to the seventh means, in the dropping step in the resist coating step, the dropping position of a predetermined amount or more of the resist solution at which a required film thickness is obtained is changed on the surface of the substrate. Therefore, it is possible to prevent the resist liquid from being dropped on the substrate surface and to suppress in-plane CD variation in the mask pattern of the exposure mask.

  According to the eighth means, in the dropping step, the resist solution is dropped 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. The resist solution can be dispersed and dropped on the surface of the substrate. That is, a predetermined amount or more of the resist solution is not concentrated and dropped at one place on the surface of the substrate, and the components constituting the resist solution that affects the resist sensitivity can be suppressed from being concentrated at the dropping position. Therefore, the occurrence of resist solution dripping traces on the substrate surface, the resist film sensitivity variation at and below the resist droplet position, and other positions can be suppressed, and in-plane CD variation in the mask pattern of the exposure mask can be suppressed. In addition, the resist solution can be dropped symmetrically with respect to the center of the substrate surface.

  According to the ninth or tenth means, since the dropping step includes a step of spreading the resist solution dropped onto the surface of the substrate to the center of the surface, the resist solution is applied to the substrate in the homogenizing step of rotating the substrate. A resist film that can be spread uniformly over the entire surface and has excellent in-plane film thickness uniformity can be formed.

  According to the eleventh means, in the dropping step, the nozzle for dropping the resist solution at a position eccentric from the center of the surface of the substrate is moved on a straight line passing through the center of the surface while the substrate is rotating. The resist solution dropped on the surface of the substrate can be rapidly spread to the center of the surface, and the resist solution dropped on the surface of the substrate can be spread quickly and uniformly outward of the substrate surface.

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

  According to the thirteenth means, in the dropping step, the nozzle for dropping the resist solution on the center of the surface of the substrate or a position eccentric from the center is arranged on a straight line passing through the center of the surface during the rotation of the substrate. Since the resist solution dropped on the surface of the substrate can be quickly spread to the center of the surface because the resist solution is moved outward, the resist solution dropped on the surface can be rapidly and uniformly distributed outward of the substrate surface. Can be spread.

  According to the fourteenth means, the chemically amplified resist is a resist having a low viscosity and is easily dried. Even with this chemically amplified resist, generation of traces of the resist solution on the surface of the substrate, resist solution Concentration of components constituting the resist solution that affects the resist sensitivity of the chemically amplified resist at the dropping position, the vicinity thereof, and other positions can be suppressed. Therefore, in-plane CD variations in the mask pattern of the exposure mask due to variations in the sensitivity of the resist film in the mask blank can be suppressed.

According to the sixteenth means, a thin film made of a chromium-containing material, and further a thin film made of a chromium-based material containing at least one element of oxygen, nitrogen, and fluorine in order to give the thin film surface an antireflection function. In this case, the surface state of the thin film becomes a state where the surface roughness becomes relatively rough, and the sensitivity tends to be high at the position where the resist solution is dropped. By applying, in-plane CD variation in the mask pattern of the exposure mask can be suppressed.
According to the seventeenth means, the resist film 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, and this resist pattern is masked. Since the mask pattern is formed and the exposure mask is manufactured, in-plane CD variation or the like in the mask pattern of the exposure mask can be suppressed. An exposure mask that can be adapted to a 65 nm pitch) can be realized.

The best mode for carrying out the present invention will be described below with reference to the 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. FIG. 4A is a cross-sectional view showing a mask blank manufactured from the substrate with a thin film in FIG. FIG. 4B is a cross-sectional view showing an exposure mask manufactured from the mask blank of FIG.

  The mask blank 10 shown in FIG. 4 is manufactured by a sputtering method, a vapor deposition method, a CVD method, or the like on a main surface 12 of a quadrangular substrate 11 to form a thin film 14 to be a mask pattern 13 for transfer to a transfer target. The mask blank 10 is manufactured by forming a resist film 16 on the surface 19 of the thin film 14 of the substrate with thin film 15 by a resist coating process. The method for manufacturing 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.

  The thin film 14 causes an optical change with respect to the exposure light (for example, ArF excimer laser). Specifically, the light-shielding film that shields the exposure light and the phase shift film that changes the phase of the exposure light. (This phase shift film also includes a halftone film having a light shielding function and a phase shift function). 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.

  The mask blank 10 has a mask pattern forming 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. The mask pattern formation region 17 varies depending on the size of the mask blank 10 and the like. For example, when the mask blank 10 has a size of 152 mm × 152 mm, the mask pattern formation region 17 is a 132 mm × 132 mm region at the center of the thin film 14 of the substrate with thin film 15. is there.

  The mask blank 10 is a transmissive mask blank or a reflective mask blank. In the case of a transmissive mask blank, a light transmissive substrate is 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) are formed as the thin film 14. 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 sequentially forms a light reflecting multilayer film and a light absorber film serving as a mask pattern on the substrate 11. It is a thing. These light reflecting multilayer film and light absorber film are the thin film 14.

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

  The spin coater 20 has a spinner chuck 21 on which the substrate 15 with a thin film is placed and rotatably held, a nozzle 22 for dropping a resist solution 26 on the surface 19 of the substrate 15 with a thin film, and a dropped resist solution. 26 is provided at the lower part of the cup 23, and a cup 23 that prevents the substrate 26 from scattering by the rotation of the substrate 15 with a thin film to the outside of the substrate 15 with a thin film and to the periphery of the spin coater 20. There is a drainage means (not shown) that collects and drains the resist solution 26 scattered to the outside of the substrate with thin film 15 while the substrate with substrate 15 is rotating. The spinner chuck 21 is connected to a motor 25, and by driving the motor 25, the thin film-coated substrate 15 held by the spinner chuck 21 is rotated under the rotation conditions 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), and the thin film is applied onto the spinner chuck 21. The substrate 15 is held. Next, while rotating the substrate 15 with the thin film via the spinner chuck 21 by the motor 25, a dropping step of spreading the resist solution 26 from the nozzle 22 on the surface 19 of the thin film 14 of the substrate 15 with the thin film, and the motor 25. And a uniformizing step of uniformly spreading the dropped resist solution 26 over the entire surface 19 of the thin film 14 of the thin film-coated substrate 15 while rotating the thin film-coated substrate 15. Then, while rotating the substrate 15 with a thin film by the motor 25, a drying process for drying the resist film 16 formed to have a uniform film thickness is sequentially performed to form the resist film 16 on the surface 19 of the thin film 14 of the substrate 15 with a thin film. Form.

  Here, the resist solution 26 is not particularly limited. However, the resist solution 26 is a high-molecular resist made of a high molecular weight resin having a viscosity of more than 10 mPa · s and an average molecular weight of 100,000 or more, and an average molecular weight of less than 10 mPa · s. Novolak type resists composed of novolak resin and dissolution inhibitor having a valence of less than 100,000, chemically amplified resists composed of polyhydroxystyrene resin and acid generator, and the like. Particularly effective in the present embodiment is a resist having a viscosity of less than 10 mPa · s and an average molecular weight of less than 100,000. Further, in the case of a resist composed of a plurality of constituent materials including a polymer, a PAG (Photo Acid Generator), and a quencher, such as a chemically amplified resist, the surface of the constituent material within the mask blank surface. The effect of the present invention is most obtained in the resist material in which the in-plane variation easily causes in-plane CD variation.

  The number of rotations and the rotation time of the thin film-coated substrate 15 in the homogenization step and the drying step are set depending on the type of the resist solution 26. In any case, as shown in FIG. The number of rotations of the substrate 15 is set higher than the number of rotations of the substrate with thin film 15 in the drying process. As a result, the resist film 16 having a uniform thickness can be formed also in the mask pattern formation region 17 that reaches the outer region of the inscribed circle 27 (FIG. 3) in the substrate 15 with a rectangular thin film.

  For example, in a chemically amplified resist or a novolak resist, since the viscosity is low (10 mPa · s or less), in the homogenization step, the substrate rotation speed is set to 850 to 2000 rpm, and the substrate rotation time is set to 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 the polymer resist is high (over 10 mPa · 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, and in the drying process, The substrate rotation speed is set to 50 to 450 rpm. The substrate rotation time in the drying process is set to the 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).

  In the resist coating process, after the drying process is completed, 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 a process. This heating and drying treatment process is usually 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 on which the resist film 16 is formed is cooled by a cooling plate; including. 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.

By the way, as shown in FIG. 1, in the dropping step to be performed before the above-described uniformizing step, a predetermined amount of resist solution 26 for obtaining a required film thickness is supplied from the nozzle 22 to the thin film of the substrate with thin film 15. 14 is a step in which the resist solution 26 is spread on the surface 19 of the substrate 15 with a thin film by being dispersed and dropped on the surface 19 of the substrate 14. More specifically, when a predetermined amount of resist solution 26 for obtaining a required film thickness is dropped from the nozzle 22 onto the surface 19, the distance from the substrate rotation center O at the position below the resist droplet (eccentric position Q, FIG. 3). And the relative movement speed of the substrate 15 and the nozzle 22 (the rotation speed of the substrate 15 when the position of the nozzle 22 is fixed) is adjusted to draw a donut-shaped dropping locus C (see FIG. 5A). ), After dropping the resist solution 26 in a lenticular shape from the start of dropping (dropping start portion 16a) to the end of dropping (see FIG. 5 (B)), this lenticular resist solution 16b is spread to form a substantially circular shape near the center of the substrate. This is a step of forming the resist pool 16c (see FIG. 5C).
Specifically, the thin film resist 15 is rotated by the motor 25 via the spinner chuck 21, and the nozzle is formed at an eccentric position Q that is eccentric by a predetermined distance from the center O of the surface 19 of the thin film resist 15 (see FIG. 3). The resist solution 26 is dropped from the nozzle 22 during the rotation of the substrate 15 with a thin film, and the resist solution 26 is placed in a donut-shaped locus at a position symmetrical to the center O of the surface 19 of the substrate 15 with a thin film. In this manner, the resist solution 16 is dropped on the surface 19 of the substrate 15 with a thin film, and the resist solution 26 is dispersed on the surface 19 of the substrate 15 with a thin film. Can be dripped.

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

The rotation speed when rotating the thin film-coated substrate 15 in this dropping step is appropriately adjusted and set from the final discharge amount and discharge speed of the resist solution 26, the dropping position of the resist solution 26, and the like. 5-50 rpm is preferable, More preferably, it is 5-25 rpm. Further, the dropping position of the resist solution 26 is preferably 1 cm to 5 cm in distance (eccentric position Q) from the substrate rotation center O at the position below the resist droplet.
If the rotational speed exceeds 50 rpm, the rotational speed of the thin film-attached substrate 15 is too large and the dropped resist solution 26 may scatter or the resist solution 26 may not spread to the center O of the surface 19 of the thin film-attached substrate 15. Thus, 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 to 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 under the resist droplet and other positions. Therefore, the rotation speed of the thin film-coated substrate 15 in the dropping step is set in a range of 0.5 to 50 rpm.

  Furthermore, 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 order to uniformly spread the liquid 26 over the entire surface 19 of the substrate 15 with a thin film to form a resist film 16 having a uniform film thickness (good in-plane film thickness uniformity), the surface 19 of the substrate 15 with a thin film It is necessary to include a step of spreading the resist solution 26 to the center O position. In this step, after the dropping of the resist solution 26 from the nozzle 22 is finished, the rotation of the substrate 15 with a thin film is stopped, and a drooping drop is drawn around the center O of the surface 19 of the substrate 15 with a thin film while drawing a donut-shaped dropping locus. This is a step of waiting until the resist solution 26 formed in the ball-shaped resist solution 16 b spreads to the center O position of the surface 19.

  Further, in the step of spreading the resist solution 26 to the position of the center O of the surface 19 of the substrate with thin film 15, the nozzle 22 set above the surface 19 of the substrate with thin film 15 is moved while the substrate with thin film 15 is rotated. This can also be realized in a dropping step of moving on the straight line L passing through the center O and the eccentric position Q on the surface 19 of the substrate 15, and the following two dropping steps can be mentioned.

  In the first dropping step, the nozzle 22 that drops the resist solution 26 is set at the eccentric position Q of the surface 19 of the substrate with thin film 15 during the rotation of the substrate with thin film 15 on the straight line L in the center O direction. To move to. The resist solution 26 dripped from the nozzle 22 set at the eccentric position Q is dripped in a ball shape while drawing a dripping locus around the center O of the surface 19 on the surface 19 of the rotating substrate 15 with a thin film. 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 drops on the surface 19 of the rotating thin film-coated substrate 15 near the center O. Will be. As a result, the resist solution 26 dropped on the surface 19 of the substrate with thin film 15 can be quickly spread to the center O position of the surface 19.

  In the second dropping step, the nozzle 22 set at the center O of the surface 19 of the substrate with thin film 15 or the eccentric position Q slightly deviated from the center O is moved on the straight line L during the rotation of the substrate 15 with thin film. The resist solution 26 is dropped from the nozzle 22 while being gradually moved outward of the substrate 15 with a thin film. 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-attached substrate 15, so that the resist solution 26 is supplied to the position of the center O of the surface 19 of the thin film-attached substrate 15. The resist solution 26 is dropped in a direction in which a centrifugal force acts on the surface 19 of the substrate 15 with a thin film, and can be spread quickly. Can be spread quickly and uniformly.

  The resist film 16 is formed on the surface 19 of the thin film 14 of the thin film-attached substrate 15 by performing the dropping process, the homogenizing process, and the drying process as described above, and the mask blank 10 shown in FIG. To do. Then, a predetermined pattern is drawn and developed on the resist film 16 of the mask blank 10 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)) to form an exposure mask 18.

Therefore, according to the said embodiment, there exist the following effects (1)-(5).
(1) In the dropping step in the resist coating step, 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 substrate 15 with the thin film while rotating the substrate 15 with the thin film. The dropping position of a predetermined amount of the resist solution 26 for obtaining a required film thickness is changed on the surface 19 of the thin film substrate 15, and the resist solution 26 is dispersed and dropped on the surface 19 of the substrate 15 with a thin film. It will be. Therefore, the predetermined amount of the 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 on the center O position of the surface 19). In the exposure mask 18 having the mask pattern 13 formed using the resist pattern formed from the resist film 16 as a mask, the pattern lines 28 ( The “in-plane CD variation” in which the line width dimension (CD) in FIG. 4B varies in the plane with respect to the target line width dimension (CD) of the target line can be suppressed.
As a result, it is possible to realize an exposure mask 18 that can meet a 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 onto the substrate surface 19, the resist solution 26 is dropped like a slant 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 as to be in different positions as the time passes, and more specifically, they are dropped like a slanted ball. Since the resist solution 22 was dropped by adjusting the distance from O to 1 cm to 5 cm and the substrate rotation speed from 0.5 rpm to 50 rpm, the resist solution 22 was concentrated on one place on the substrate surface 19. It is not dripped, and it can suppress that the component which comprises the resist liquid which affects resist sensitivity concentrates on the location of a dripping position. Therefore, in the exposure mask 18 having the mask pattern 13 formed using the resist pattern formed by the exposure / development process on the resist film 16 of the mask blank manufactured by the above manufacturing method as a mask, the resist solution 26 The line width (CD) of the pattern line 28 (FIG. 4 (B)) of the mask pattern due to the sensitivity variation of the resist film is the target line width of the target line. It is possible to suppress “in-plane CD variation” that varies in a plane with respect to the dimension (CD). As a result, it is possible to realize an exposure mask 18 that can meet a demand for pattern miniaturization of a transfer target (for example, a generation after a half pitch 65 nm node in a semiconductor device).

  (3) Since the dropping step in the resist coating step includes the step of spreading the resist solution 26 dropped onto 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 rotated uniformly. In the process, the resist solution 26 can be spread uniformly over the entire surface 19 of the substrate 15 with a thin film to form the resist film 16 having a uniform thickness.

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

  (5) In the dropping step in the resist coating step, the nozzle 22 for dropping the resist solution to 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 being rotated. In addition, when moving outward on a straight line L passing through the center O of the surface 19 and the eccentric position Q, the resist solution 26 dropped on the surface 19 of the substrate with thin film 15 is moved to the position of the center O of the surface 19. The resist solution 26 dropped on 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 a required film thickness is changed on the surface 19 of the substrate 15 with a thin film, and the resist solution 26 is dispersed on the surface 19 of the substrate 15 with a thin film. Even if the resist solution 26 is a chemically amplified resist that has a low viscosity and is easily dried, generation of traces of the dropping of the resist solution 26 on the surface 19 of the substrate with a thin film In the vicinity and other positions, it is possible to suppress the concentration of the components constituting the resist solution affecting the resist sensitivity of the chemically amplified resist from being concentrated at the dropping position. Therefore, in-plane CD variations in the mask pattern 13 of the exposure mask 18 due to sensitivity variations in the resist film 16 in the mask blank can be suppressed.

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

Example 1
A chromium film and a chromium oxynitride film were sequentially formed on a synthetic quartz glass substrate having a size of 152.4 mm × 152.4 mm by a sputtering method to obtain a substrate with a thin film in which a thin film of a light shielding film and an antireflection film was formed. .
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 Electronics Materials)
Dropping step: The resist solution was dropped while rotating the substrate with the thin film.
Substrate rotation speed: 5 rpm
Method for dropping resist onto substrate: The resist solution was dropped at an eccentric position 3 cm eccentric from the center of the surface of the substrate with a thin film, and after the substrate was rotated at least once, 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 as to be dropped like a dovetail from the start of dropping to the end of dropping while drawing a 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 standby, the resist solution spreads from the dropping position to the outer peripheral direction of the thin film-coated substrate as well as the central direction. That is, a substantially circular resist pool was formed near the center of the substrate surface (near the center).
Uniformization process Substrate rotation speed: 1500rpm
Substrate rotation time: 2 seconds Drying process Substrate rotation speed: 250 rpm
Next, the substrate with the thin film on which the resist film was formed was conveyed to a heat drying apparatus and a cooling apparatus, and a predetermined heat drying process was performed to dry the resist film, thereby preparing a mask blank for ArF excimer laser exposure.

The film thickness distribution of the obtained mask blank resist film was measured. As a result, the average film 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 is measured at 29 × 29 = 841 measurement points arranged uniformly over the entire 132 mm × 132 mm square area (that is, mask pattern formation region) at the center of the surface of the substrate with a thin film. The film thickness was measured using a reflective film thickness meter (manufactured by Nanometrics Japan Co., Ltd .: AFT6100M), and the average film thickness was determined from the measured film thickness data. The in-plane film thickness uniformity was determined as “(maximum value of film thickness) − (minimum value of film thickness) = (in-plane film thickness uniformity)” from the film thickness data at each measurement point.

Next, a predetermined pattern was drawn on the resist film by an electron beam drawing apparatus, and a heat treatment and a development treatment were performed to form a resist pattern. Using this resist pattern as a mask, dry etching 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 mask of the exposure mask, is measured by the length measuring 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 in the plane of the mask, was measured. As a result, the in-plane CD variation achieved 4 nm at 3σ, and the result of satisfying 5.1 nm (in the case of a line and space pattern) that is the demand for pattern miniaturization of semiconductor devices in the next generation (half pitch 65 nm node) became.

(Comparative example)
A mask blank was produced 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, and an exposure mask was produced from this mask blank.
Dropping step: A predetermined amount of resist solution for obtaining a required film thickness was dropped onto the center of the surface of the substrate with a thin film without rotating the substrate with a thin film.
The average film thickness and in-plane film thickness uniformity of the resist film in the obtained mask blank were substantially the same as those in Example 1.
The in-plane CD variation (3σ) of the exposure mask produced from this mask blank was 7 nm. This in-plane CD variation (3σ) of 7 nm did not satisfy 5.1 nm (in the case of a line and space pattern), which is a demand for pattern miniaturization of semiconductor devices in the next generation (half pitch 65 nm node).
The resist film surfaces formed in the mask blank with a resist film in Example 1 and the mask blank with a resist film in Comparative Example 1 were subjected to 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 lower in the outer peripheral portion than in the central portion. It was a trend.
This is because the chemical amplification resist formed on the mask blank of Example 1 contains the polymer, PAG, and quencher constituent materials that constitute the chemical amplification resist uniformly in the mask blank surface. The chemically amplified resist formed on the mask blank of Comparative Example 1 does not contain the constituent materials of the polymer, PAG, and quencher that are included in the chemically amplified resist uniformly in the mask blank surface. It is thought that the difference appeared in the difference in in-plane CD variation.

(Example 2)
The resist solution in Example 1 was changed to a negative chemical amplification resist NEB22 (manufactured by Sumitomo Chemical Co., Ltd.), and in the resist coating process, the substrate rotation speed was set to 800 rpm, and the substrate rotation time was set to 4 seconds. A mask blank is produced in the same manner as in Example 1 except that the substrate rotation speed is set to 300 rpm in the drying process. From this mask blank, the mask pattern is an isolated line pattern, and the line width dimension (CD ) Produced an exposure mask having a thickness of 180 nm.
The average film thickness and in-plane film thickness uniformity of the resist film in the obtained mask blank were substantially 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 (3σ) 2 nm was able to satisfy 3.6 nm (in the case of an isolated line pattern), which is a demand for pattern miniaturization of semiconductor devices in the next generation (half pitch 65 nm node). This is considered to be caused by the fact that the polymer, PAG, and quencher constituent materials constituting the chemically amplified resist are uniformly contained in the mask blank surface.
(Comparative Example 2)
The resist dropping method on the substrate is adjusted appropriately as described above in Patent Document 2, and the dropping position of the resist solution and the number of rotations of the substrate are appropriately adjusted to drop the resist solution onto the substrate in a donut shape, thereby forming a slanted resist state. A mask blank was prepared in the same manner as in Example 1 except that a resist pool was immediately formed in the vicinity of the center of the substrate without passing through the above, and an exposure mask was prepared from this mask blank.
The average film thickness and in-plane film thickness uniformity of the resist film in the obtained mask blank were substantially the same as those in Example 1.
The in-plane CD variation (3σ) of the exposure mask produced from this mask blank was 6.8 nm. This in-plane CD variation (3σ) of 6.8 nm did not satisfy 5.1 nm (in the case of a line and space pattern), which is a demand for pattern miniaturization of semiconductor devices in the next generation (half pitch 65 nm node). . The resist solution pressure on the substrate under the resist droplet is large, and the constituent materials of the polymer, PAG, and quencher that constitute the chemically amplified resist are not evenly contained in the mask blank surface, and have variations. This is considered to be one factor.
(Examples 3 to 4)
In Example 1 above, a mask blank was prepared in the same manner as in Example 1 except that the dropping position of the resist was 1 cm (Example 3) and 5 cm (Example 4) from the center of the surface of the substrate with the thin film. An exposure mask was prepared from this mask blank.
The average film thickness and in-plane film thickness uniformity of the resist film in the obtained mask blank were substantially the same as those in Example 1.
The in-plane CD variation (3σ) of the exposure mask produced from this mask blank was 5 nm (Example 3) and 4.7 nm (Example 4). This in-plane CD variation (3σ) satisfied 5.1 nm (in the case of a line and space pattern), which is a demand for pattern miniaturization of semiconductor devices in the next generation (half pitch 65 nm node).
(Examples 5-6)
Example 3 in Example 4 except that the rotation speed of the substrate at the time of dropping the resist was 0.5 rpm (Example 5), and the rotation speed of the substrate at the time of dropping the resist in Example 3 was 50 rpm (Example 6). 4, a mask blank was produced, and an exposure mask was produced from this mask blank.
The average film thickness and in-plane film thickness uniformity of the resist film in the obtained mask blank were substantially the same as those in Example 1.
The in-plane CD variation (3σ) of the exposure mask produced from this mask blank was 4.8 nm (Example 5) and 5 nm (Example 6). This in-plane CD variation (3σ) satisfied 5.1 nm (in the case of a line and space pattern), which is a demand for pattern miniaturization of semiconductor devices in the next generation (half pitch 65 nm node).
In addition, in the case where the resist solution is dropped under the conditions deviating from the optimum resist dropping conditions (distance from the substrate rotation center of 1 cm to 5 cm, substrate rotation speed of 0.5 rpm to 50 rpm) in the present invention, A resist film with a uniform film thickness can be formed without the variation of the internal CD satisfying the demand for pattern miniaturization of semiconductor devices in the next generation (half pitch 65 nm node) or the resist solution does not reach the substrate rotation center. As a result, there was a problem that something that was not done occurred.

  As mentioned above, although this invention was demonstrated based on the said embodiment, this 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. Further, 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 from a high rotation speed to a low rotation speed. Also good.

It is a sectional side view which shows the spin coater for implementing the resist coating process in one Embodiment of the manufacturing method of the mask blank which concerns on this invention. It is a graph which shows the relationship between the rotation speed and rotation time of a board | substrate in the resist coating process using the spin coater of FIG. It is a top view which shows the board | substrate with a thin film of FIG. (A) is sectional drawing which shows the mask blank manufactured from the board | substrate with a thin film of FIG. 1, (B) is sectional drawing which shows the mask for exposure manufactured from the mask blank of FIG. 4 (A). . It is a top view which shows the dripping state of the resist liquid of the board | substrate surface of the dripping process in the manufacturing method of the mask blank which concerns on this invention, Comprising: (A) is the dripping state of the resist liquid at the time of dripping start of a resist liquid, and resist liquid FIG. 6B is a plan view showing a dropping state of the resist liquid at the time when the resist liquid is dropped from after the dropping start of the resist liquid to the end of dropping, and FIG. It is a top view which shows the state which finished dripping a resist liquid on the surface and formed the resist pool in the board | substrate center vicinity.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Mask blank 11 Board | substrate 13 Mask pattern 14 Thin film 15 Substrate with a thin film 16 Resist film 16b Ball-shaped resist liquid 18 Exposure mask 19 Surface 20 Spin coating apparatus 22 Nozzle 26 Resist liquid O Center Q Eccentric position

Claims (9)

  When the resist solution is dropped from the nozzle onto the substrate surface, the resist solution is dropped on the surface of the substrate so that the resist solution drops at a different position, and then the dropped resist solution is spread to collect the resist near the center of the substrate. And a resist film is formed by diffusing the resist pool to the peripheral portion of the substrate surface by centrifugal force and then drying the resist pool.   2. The method of manufacturing a 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 different with time.   When the resist solution is dropped from the nozzle onto the substrate surface, the distance from the substrate rotation center at the lower position of the resist droplet and the relative movement speed of the substrate and the nozzle are adjusted, and the resist solution is dropped in a slanting shape. The manufacturing method of the mask blank of Claim 1 or 2. When the resist solution is dropped onto the substrate surface from the nozzle, the distance from the substrate rotation center at the position below the resist droplet so that the resist sensitivity is suppressed compared to other positions at the position where the resist solution is dropped onto the substrate surface. Then, adjusting the number of rotations of the substrate within the following range, dropping the resist solution, spreading the dropped resist solution to form a resist pool near the center of the substrate, and removing the resist pool on the substrate surface by centrifugal force A method of manufacturing a mask blank, comprising: diffusing to a peripheral portion and then drying to form a resist film.
Distance from the substrate rotation center at the position below the resist droplet: 1 cm to 5 cm Substrate rotation speed: 0.5 rpm to 50 rpm A method of manufacturing a mask blank having 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, when a predetermined amount or more of a resist solution capable of obtaining a required film thickness is dropped from the nozzle, the resist solution is prevented from increasing the sensitivity at the position where the resist solution is dropped on the substrate surface compared to other positions. In addition, 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 ranges, and the resist liquid is dispersed and dropped onto the surface of the substrate, thereby producing a mask blank. Method.
Distance from the substrate rotation center at the position below the resist droplet: 1 cm to 5 cm Substrate rotation speed: 0.5 rpm to 50 rpm   6. The method of manufacturing a mask blank according to claim 1, wherein the resist solution is made of a chemically amplified resist.   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.   The method for manufacturing a mask blank according to claim 7, wherein the thin film is made of a material containing chromium.   A mask blank resist film manufactured by the mask blank manufacturing method according to claim 1 is patterned to form a resist pattern, and the resist pattern is used as a mask to form a mask pattern for exposure. A method for producing an exposure mask, comprising producing a mask.

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