KR20120050954A - Multi-gray scale photomask and manufacturing method thereof, and pattern transfer method - Google Patents

Abstract

PURPOSE: A method for manufacturing a photo-mask and a method for transferring patterns are provided to reduce the variation of transmissivity in plane of the photo-mask. CONSTITUTION: A method for manufacturing a photo-mask includes the following: a semi-transmissive film(24) is formed on a transparent substrate and transmits a part of exposing light; the semi-transmissive film is patterned to form transferring patterns including a semi-transmissive part; the exposing light transmissivity of a plurality of semi-transmissive parts in the transferring patterns is measured; the selected part of the semi-transmissive part is differently surface-treated based on the measuring result to vary exposing light transmissivity. The surface treating process includes an energy irradiating process with respect to the selected part of the semi-transmissive part.

Description

MULTI-GRAY SCALE PHOTOMASK AND MANUFACTURING METHOD THEREOF, AND PATTERN TRANSFER METHOD

The present invention relates to a multi-gradation photomask used in a photolithography step, a method for producing the same, and a pattern transfer method.

Background Art Conventionally, in the manufacture of electronic devices such as liquid crystal devices, a photolithography step is used to expose a resist film formed on a layer to be etched under a predetermined exposure condition using a photomask having a predetermined pattern. Is transferred and the resist film is developed to form a resist pattern. Then, the processing layer is etched using this resist pattern as a gradation mask.

In recent years, the usefulness of the multi-gradation mask of three or more gradations is recognized by the electronic device manufacturer, and the use of such a multi-gradation photomask is expanded. The multi-gradation photomask having three or more gradations has a translucent portion composed of a translucent film that transmits a part of the exposure light. As such a multi-gradation photomask, there exist some which are disclosed by Unexamined-Japanese-Patent No. 2007-271696.

On the other hand, such a multi-gradation photomask has been used as a large size photomask for liquid crystal display device manufacture. In the photomask for this use, it is important to make the resist residual film value formed on the transfer object constant during use of the mask by reducing the variation in the transmittance in the plane in the photomask. This is because the processing accuracy and stability of the transfer object are greatly improved. However, in the technique disclosed in Japanese Patent Laid-Open No. 2007-271696, although the variation of the transmittance between individual objects of the photomask is reduced, the problem of reducing the variation of the transmittance in the plane of the photomask is reduced. It is not a solution.

This invention is made | formed in view of such a point, Comprising: It aims at providing the multi-gradation photomask which can make the fluctuation | variation of in-plane transmittance | permeability in a photomask, and its manufacturing method.

In the multi-gradation photomask according to one aspect of the present invention, a light shielding film and a semi-transmissive film through which a part of the exposure light is transmitted are formed on the transparent substrate, respectively, and predetermined patterning is performed on each film to form a part of the light shielding part and the exposure light. A multi-gradation photomask formed by forming a transfer pattern comprising a transflective portion and a transmissive portion, wherein at least a portion of the surface is modified on at least a portion of the translucent film, and in-plane transmittance of the translucent portion existing in the transfer pattern is present. Characterized in that the distribution range is within 2%.

The above-described multi-gradation photomask is patterned by wet etching on the semi-transmissive film and the light-shielding film that transmit a portion of the exposure light, respectively, to form the transfer pattern, and the surface of at least a part of the semi-transmissive film in the transfer pattern. It is obtained by performing a modification process and changing the exposure light transmittance of the said translucent film. It is also possible to increase chemical resistance. According to this multi-gradation photomask, the variation of the transmittance | permeability in surface inside a photomask can be made small.

In the above-mentioned multi-gradation photomask, it is preferable that the said translucent film is comprised from the material containing metal silicide.

In the above-mentioned multi-gradation photomask, it is preferable that the said translucent film is comprised from the material which does not contain nitrogen substantially.

According to another aspect of the present invention, there is provided a method of manufacturing a multi-gradation photomask, by preparing a photomask blank on which a light shielding film and a semi-transmissive film that transmits a part of exposure light are prepared, and performing predetermined patterning on each film. A manufacturing method of a multi-gradation photomask for forming a transfer pattern comprising a light shielding portion, a semi-transmissive portion that transmits a part of exposure light, and a light-transmitting portion, wherein the semi-transmissive film and the light-shielding film are respectively patterned by etching. A pattern forming step of forming a transfer pattern, and a surface modification treatment on at least a part of the translucent film in the transfer pattern to change the exposure light transmittance of the translucent film, thereby allowing the in-plane transmittance of the translucent portion present in the transfer pattern. And a surface modification process that reduces the distribution range. Regarding the etching, at least the etching of the translucent film is noticeable when the wet etching is applied.

According to this method, a multi-gradation photomask with a small variation in the transmittance of the translucent portion in the plane can be obtained. In addition, in this method, since the surface modification treatment can be selectively performed on a region having a low transmittance due to various factors, only an inadequate transmittance can be corrected, and the in-plane variation can be effectively suppressed. Therefore, it is preferable that surface modification process includes performing process different from another part with respect to the selected part in the said photomask surface.

In the manufacturing method of the multi-gradation photomask mentioned above, it is preferable that a surface modification process includes the process which raises the chemical-resistance of the said translucent film. Moreover, in the manufacturing method of the multi-gradation photomask mentioned above, it is preferable that the said surface modification process is a process which irradiates predetermined energy to the semi-transmissive part in the said transfer pattern.

In the manufacturing method of the multi-gradation photomask mentioned above, it is preferable that the said surface modification process is a process which heats the semi-transmissive part in the said transfer pattern.

In the manufacturing method of the multi-gradation photomask mentioned above, after the said pattern formation process, it has a process of measuring the transmittance | permeability of the said several translucent part, In the said surface modification process, it is based on the said measurement result, It is preferable to perform a surface modification treatment on at least a part of the translucent film so as to reduce the in-plane distribution range of the transmissivity of the translucent portion, preferably to 2% or less. In addition, it is preferable that the measurement of the said transmittance | permeability is a measurement of the effective transmittance mentioned later.

The pattern transfer method according to still another aspect of the present invention is characterized by transferring the transfer pattern of the multi-gradation photomask to the work layer by irradiating exposure light by an exposure machine using the multi-gradation photomask. In this case, it is preferable to use exposure light including a wavelength band of i-g line as the exposure light.

BRIEF DESCRIPTION OF THE DRAWINGS The figure which shows the relationship between the surface modification process and the transmittance | permeability fluctuation amount.
2 (a) and 2 (b) show in-plane variations of a photomask before and after surface modification.
3 (a) and 3 (b) are diagrams for explaining the transmittance of the semi-transmissive region.
4 shows an apparatus for measuring an effective transmittance.
5A to 5G are views for explaining a method for manufacturing a multi-gradation photomask according to an embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, embodiment of this invention is described in detail with reference to an accompanying drawing.

In multi-gradation photo masters, it is known to use metal silicide as a material of the translucent portion. However, this material may not necessarily have high chemical resistance, light resistance, or the like for a given drug. In the multi-gradation photomask used in large photomasks, such as for liquid crystal display device manufacture, MoSix can be used effectively as a material of a translucent film, for example. However, in that case, the chemical resistance may not be sufficient depending on the chemical liquid used in the mask manufacturing process or the defect correction process, and even after forming a semi-transmissive film having a desired transmittance in the step of the photomask blank, the subsequent phenomenon In the cleaning process, there is a problem that the transmittance is changed.

MoSix originally has some differences depending on the film forming method, but the chemical resistance against acids and alkalis is not necessarily large. For example, the surface of the MoSix elutes slightly due to contact with alkali, thereby changing (increasing) the film's transmittance. There is a case. Usually, in manufacture of a photomask, an acid and an alkali are used for a washing process, and alkali is used for the developing process of a resist. These steps are performed for each photolithography during the manufacture of the photomask (for example, at least twice if it is a normal three-gradation photomask). Therefore, the surface of MoSix cannot be prevented from being completely damaged at every contact with acid and alkali. In particular, in the second layer photolithography, MoSix is in contact with the resist developer, and thus damage is caused.

On the other hand, in a large photomask for manufacturing, such as a liquid crystal display device, since size is large, it is not easy to dry-etch in a vacuum chamber. For this reason, wet etching is advantageous at the time of patterning. Therefore, as the material of the translucent film, it is necessary to form a pattern accurately at a proper etching time by wet etching. In other words, when a material having a very high chemical resistance is used as the material of the translucent film, there is a problem such as reducing the speed of wet processing.

By the way, in a multi-gradation photomask, the light quantity of the exposure light which permeate | transmits a photomask is selectively reduced, and the resist pattern with a predetermined step | step is formed in the resist film on a to-be-transferred body. By doing in this way, there exists an advantage that the photolithography process in electronic device manufacturing processes, such as a liquid crystal display device, can be simplified, and two photolithography processes can be performed using one mask. However, for this purpose, it is very important to preliminarily calculate the resist step required in the processing step (development, etching step) of the electronic device to be obtained, and to realize the resist residual film value with good stability. That is, the exposure light transmittance of the multi-gradation photomask for producing such a desired resist residual film value must also be accurately controlled. This becomes increasingly important not only in the three-gradation photomask but also in the multi-gradation photomask of four or more gradations.

In addition, it is ideal to perform wet processing steps such as a cleaning step, a developing step, and a resist peeling step under the same conditions with respect to the transfer pattern formed on the large sized substrate as described above. , Not necessarily easy. When in-plane nonuniformity arises in these processes, it may become impossible to satisfy product specification.

Therefore, in embodiment of this invention, the transmittance | permeability is changed by performing predetermined surface modification process on the semi-transmissive part (for example, formed by MoSix) after patterning. Moreover, the chemical-resistance of the photomask which has a desired transmittance | permeability can be improved, and the subsequent process can prevent the fluctuation | variation of a transmittance | permeability. In this case, the inspection of the transmittance is performed after the patterning, and based on the result of the inspection of the transmittance, the surface modification treatment can be selectively performed on the predetermined part in the plane different from the other parts.

Here, the inventors investigated the change in transmittance when the surface was modified by means of irradiating energy or heating the semitransmissive membrane using MoSix as a material of the semitransmissive membrane. Here, as a process for irradiating energy, vacuum ultraviolet irradiation treatment (VUV treatment) under conditions of wavelength 172 nm, output 40 kW / cm 2, and irradiation distance 3 mm is performed, and as a heat treatment, a transparent substrate temperature is used by using a halogen heater. Was heated to 250 ° C, 300 ° C, and 400 ° C and heated for 10 minutes. The result is shown in FIG. As can be seen from FIG. 1, the light transmittance increased by irradiating energy or heating the translucent film.

Therefore, the present inventors prepared the photomask blank which formed the translucent film and the light shielding film into a film, and produced the photomask which formed the transfer pattern by performing predetermined patterning by wet etching to each film. As the transfer pattern, one having a repeating pattern in which the same translucent portion was regularly arranged was used. An experiment was performed to reduce in-plane variations in transmittance of the translucent portion by selectively performing the surface modification treatment on a part of the translucent film in this transfer pattern.

FIG.2 (a) shows the light transmittance distribution (relative to i-g line) of the photomask in which the said transfer pattern was formed before surface modification process. Here, the size of each bubble represents the rate of change (relative value) to the side where the white bubble has a low transmittance, and the side where the shaded bubble has a high transmittance. Here, the VUV treatment was selectively performed on the portion of the back bubble reflecting the variation rate of the transmittance, followed by heat treatment. As a result, as shown in Fig. 2B, the in-plane distribution of transmittance could be reduced. Here, finally, the in-plane distribution of exposure light transmittance could be 2% or less. In addition, the measurement of the transmittance | permeability performed here is mentioned later.

In the surface modification treatment, the VUV treatment and the heat treatment may be performed individually individually or may be simultaneously performed. Alternatively, the VUV treatment may be performed multiple times so as to be within a desired transmittance range locally or as a whole. In this case, the transmittance measurement may be performed during a plurality of processes. In addition, for the purpose of increasing the light transmittance and / or chemical resistance of the entire mask surface, a VUV treatment or heat treatment may be performed on the entire photomask surface. In addition, you may simultaneously perform both processes to the whole surface.

In particular, the effect of increasing the light transmittance is remarkable in the VUV treatment, and the effect of the increase in the light transmittance and the increase in chemical resistance is remarkable in the heat treatment. As a preferable embodiment, for example, the VUV treatment may be performed at a predetermined position in the plane, and then heat treatment may be performed on the entire surface to achieve a desired light transmittance, and the light transmittance may not be changed further. Alternatively, the VUV treatment may be performed at a predetermined position in the plane, and then the VUV treatment and the heat treatment may be performed on the entire surface. Moreover, heat processing is highly effective in raising chemical-resistance of a translucent film, and it is preferable to carry out at the end of surface modification treatment. As surface treatment conditions, the temperature of heat processing can be about 100 degreeC-500 degreeC, and the output of a VUV process can be set to 20W / cm <2> -100W / cm <2> (irradiation distance 1mm-20mm).

In addition, it is known in advance that a change in transmittance occurs in the surface modification treatment, and the amount of variation in the transmittance in the surface modification treatment of the increase in transmittance is determined in advance in consideration of that much. Moreover, it is also a preferable aspect to presuppose the light transmittance which rises by surface modification process, and to design the film transmittance (composition, film thickness) of a semi-transmissive film.

Said transmittance | permeability measurement can be performed with a membrane transmittance | permeability measuring apparatus. For example, when the transmissivity of individual semi-transmissive portions becomes different in a pattern in which a plurality of semi-transmissive portions of the same shape are repeated, such as when a film thickness distribution occurs in the plane due to the film formation of the translucent film, A measurement is performed and the surface modification process mentioned above can be performed according to the result.

On the other hand, the effective transmittance (hereinafter, referred to as effective transmittance) of each semi-transmissive portion in the case of actually exposing the mask by an exposure machine may vary depending on not only the film quality and film thickness of the semi-transmissive membrane but also the pattern shape. have. Therefore, after grasping the effective transmittance which reflected all these, it is preferable to perform surface modification process.

For example, in the photomask for manufacturing a liquid crystal display device, a portion corresponding to the channel portion may be formed as a semi-transmissive portion, and portions corresponding to a source and a drain may be formed as light shielding portions. In such a pattern, the transflective portion having the portion adjacent to the light shielding portion decreases the transmittance in the vicinity of the adjacent portion due to the influence of diffraction under the optical conditions of the exposure machine (at the resolution of the exposure unit). For example, as shown to (a) and (b) of FIG. 3, the light intensity distribution of the transmitted light of the semi-transmissive area | region B sandwiched between the light shielding parts A falls generally, and a peak becomes low. This tendency is remarkable as the line width of the semi-transmissive region B becomes smaller, and therefore, especially in the channel portion having a small line width surrounded by the source and drain, the exposure light transmittance is lower than the transmittance inherent in the semi-transmissive film used. . In short, the transmittance of the semi-transmissive portion actually used in the pattern is different from the intrinsic transmittance of the semi-transmissive film found in a sufficiently large area. Therefore, about the test | inspection of the transmittance | permeability after the said patterning, it is preferable to carry out based on the effective transmittance rather than the intrinsic transmittance | permeability of a translucent film.

Of course, in the semi-transmissive portion adjacent to the transmissive portion, the smaller the line width of the semi-transmissive portion is, the effect of diffraction of the exposure light is, more effectively, than the light transmittance inherent in the translucent film.

Therefore, in embodiment of this invention, the semi-transmissive film and the light shielding film are patterned by wet etching, respectively, and a transfer pattern is formed, and after this pattern formation process, the effective transmittance | permeability of several semi-transmissive part is measured and this measurement is carried out. Based on the result, at least a part of the semitransmissive film in the transfer pattern is subjected to a surface modification to change the exposure light transmittance of the semitransmissive film, thereby reducing the in-plane distribution. In addition, it is more preferable to increase the chemical resistance. That is, the core of the embodiment of the present invention measures the effective transmittance of the plurality of semi-transmissive portions after the pattern forming step, and in the surface modification process, based on the measurement result, the in-plane of the effective transmittances of the plurality of semi-transmissive portions of the transfer pattern. Surface modification treatment is performed on at least a part of the translucent film so that the distribution range is 2% or less.

Here, the effective transmittance is a transmittance including not only the inherent transmittance of the film but also factors such as the shape (dimension or critical dimension) in the pattern or the optical conditions (light source wavelength, numerical aperture, sigma value, etc.) of the exposure machine. Therefore, when the width in the pattern is specified, the effective transmittance of the width is specified, and the optical conditions are fixed, the translucent portion of the semi-transmissive portion is based on the effective transmittance. It is possible to determine the design (composition, film thickness, degree of modification) of the membrane, or to determine the degree of modification of the membrane.

In addition, after the photomask is produced, when the transmittance distribution of the translucent portion in the plane is generated by the chemical liquid treatment used in the processing step, the distribution is grasped in advance, and the surface modification treatment described above is performed based on the result. Therefore, the in-plane distribution can be reduced.

As means for measuring said effective transmittance | permeability, it is preferable to reproduce or approximate the exposure conditions by an exposure machine. As such an apparatus, the apparatus shown in FIG. 4 is mentioned, for example. This apparatus comprises a light source 1, an irradiation optical system 2 for irradiating light from the light source 1 to the photomask 3, and an objective lens system 4 for forming an image transmitted through the photomask 3. And the imaging means 5 for imaging the image obtained through the objective lens system 4.

The light source 1 emits a light beam having a predetermined wavelength, and for example, a halogen lamp, a metal halide lamp, a UHP lamp (ultra high pressure mercury lamp), or the like can be used. For example, it can use as a light source which has the spectral characteristic approximating the exposure machine using a mask.

The irradiation optical system 2 guides the light from the light source 1 to irradiate the photomask 3 with light. This irradiation optical system 2 is provided with an aperture mechanism (opening aperture 7) in order to make the numerical aperture NA variable. It is preferable that this irradiation optical system 2 is provided with the visual field stop 6 for adjusting the irradiation range of the light in the photomask 3. The light passing through this irradiation optical system 2 is irradiated to the photomask 3 held by the mask holder 3a. This irradiation optical system 2 is disposed in the case 13.

The photomask 3 is held by the mask holder 3a. The mask holding tool 3a supports the lower end of the photomask 3 and the vicinity of the side edges of the photomask 3 while the main plane of the photomask 3 is substantially vertical, and tilts the photomask 3. It is fixed and kept. The mask holder 3a is a photomask 3, which is a large (for example, 1220 mm x 1400 mm, 13 mm thick or more) main photo plane, or photomasks of various sizes. (3) can be maintained. In addition, an approximately perpendicular means that the angle from the perpendicular | vertical shown by (theta) in FIG. 4 is within about 10 degrees. Light irradiated to the photomask 3 passes through the photomask 3 and enters the objective lens system 4.

The objective lens system 4 includes, for example, a first group (simulator lens) 4a which receives light passing through the photomask 3 and applies infinity correction to the light beam to be parallel light, and It consists of the 2nd group (imaging lens) 4b which forms the light beam which passed through 1 group. The simulator lens 4a is provided with an aperture mechanism (opening aperture 7), and the numerical aperture NA is variable. The light beam passing through the objective lens system 4 is received by the imaging means 5. This objective lens system 4 is disposed in the case 13.

The imaging means 5 captures an image of the photomask 3. As this imaging means 5, imaging elements, such as CCD, can be used, for example.

In this apparatus, since the numerical aperture of the irradiation optical system 2 and the numerical aperture of the objective lens system 4 are respectively variable, the ratio of the numerical aperture of the irradiation optical system 2 to the numerical aperture of the objective lens system 4, that is, The sigma value (σ: coherence) can be varied.

Moreover, in this apparatus, the control means which has the calculation means 11 and the display means 12 which perform image processing, an operation, the comparison with a predetermined threshold value, and display with respect to the picked-up image obtained by the imaging means 5, etc. The movement operation means 15 which changes the position of 14 and the case 13 is provided. For this reason, a predetermined calculation is performed by a control means using the obtained captured image or the light intensity distribution obtained based on this, and the picked-up image under the conditions using other exposure light, or light intensity distribution and transmittance | permeability can be calculated | required. .

In the apparatus shown in Fig. 4 having such a configuration, since the NA and sigma values are variable and the source of the light source can be changed, the exposure conditions of the various exposure apparatuses can be reproduced. In general, in the case of easily approximating an exposure apparatus of a large-scale photomask, such as for manufacturing a liquid crystal device, NA is 0.08 as the exposure optical system using irradiation light obtained by equalizing the light intensity by i-line, h-line, and g-line. What is necessary is just to apply the conditions whose coherence (sigma) which is NA ratio of an irradiation system and an objective system is about 0.8.

In the multi-gradation photomask according to the embodiment of the present invention, a photomask blank in which a translucent film and a light shielding film are formed is prepared, patterned by wet etching on each film to form the transfer pattern, and the transfer is performed. At least a part of the semi-transmissive film in the pattern is subjected to surface modification to change the exposure light transmittance of the semi-transmissive film. Moreover, it is preferable to improve chemical resistance by the said process. Thereby, the transmittance in-plane distribution range of the semi-transmissive portion to obtain a predetermined exposure light transmittance present in the transfer pattern is characterized by being within 2%.

A glass substrate etc. are mentioned as a transparent substrate. Moreover, as a light shielding film which shields exposure light, metal silicide films, such as metal films, such as a chromium film, a silicon film, a metal oxide film, and a molybdenum silicide film, etc. are mentioned. In addition, it is preferable to use what laminated | stacked the antireflection film as a light shielding film, and chromium oxide, nitride, carbide, a fluoride etc. are mentioned as an antireflection film. As the semi-transmissive film which partially transmits the exposure light, an oxide of chromium, nitride, carbide, oxynitride, oxynitride carbide, metal silicide or the like can be used. In particular, a metal silicide film such as a molybdenum silicide compound (MoSix, MoSiO, MoSiN, MoSiON, MoSiCON, etc.) film is preferable. However, in order to have appropriate wet etching property, it is preferable that the translucent film is comprised from the material which does not contain nitrogen substantially.

As described above, according to the embodiment of the present invention, a multi-gradation photomask having a small variation in in-plane transmittance can be obtained. In addition, in this method, various factors (e.g., in-plane nonuniformity due to line width distribution, in-plane nonuniformity due to variation in film thickness during film formation, and in-plane transmittance nonuniformity due to wet treatment such as development and etching) In consideration of the above, since the surface modification treatment can be selectively performed on a region having a low transmittance, a correction can be made to bring the transmittance close to a desired value, and the in-plane variation can be effectively suppressed. In addition, the resistance of the translucent film can be improved so that the variation in transmittance due to subsequent chemical liquid contact is suppressed.

An example of the process of manufacturing the photomask which concerns on embodiment of this invention is shown in FIG. Specifically, it performs by the process shown to Fig.5 (a)-(g), for example. In addition, the manufacturing method of the structure shown in FIG. 5 is not limited to these methods. Here, the material of the translucent film 24 is made of molybdenum silicide (MoSix). In addition, in the following description, the resist material which comprises a resist layer, the etchant used at the time of an etching, the developing solution used at the time of image development, etc. select suitably what can be used by a well-known photolithography and an etching process. For example, an etchant is appropriately selected depending on the material constituting the etching target film, and a developer is appropriately selected depending on the resist material to be used.

As shown in FIG. 5A, a photomask blank in which a translucent film 24 and a light shielding film 22 (the antireflection film 23 is formed on the surface thereof) is prepared on the transparent substrate 21. Then, a resist layer 25 is formed on the photomask blank, and as shown in Fig. 5B, the resist layer 25 is exposed and developed so that only the transmissive region is exposed to form an opening. Next, as shown in Fig. 5C, using the resist pattern as a mask, the exposed antireflection film 23, the light shielding film 22, and the semi-transmissive film 24 are etched, and then the figure is shown. As shown in 5d, the resist layer 25 is removed. The resist pattern may be peeled off before the semitransmissive film 24 is etched, and the semitransmissive film 24 may be etched using the antireflection film 23 and the light shielding film 22 as masks.

Next, as shown in FIG. 5E, a resist layer 25 is formed over the light shielding region of the anti-reflection film 23, and as shown in FIG. 5F, the resist pattern is masked. The anti-reflective film 23, light shielding film 22, and semi-transmissive film that were exposed are etched, and then the resist layer 25 is removed as shown in Fig. 5G.

Next, about the photomask in which the pattern was formed in this way, the effective transmittance | permeability of each semi-transmissive part is measured using the apparatus shown in FIG. Then, based on the in-plane variation in the effective transmittance, the surface of the semitransmissive film 24 is modified by modifying the surface of the semitransparent film 24 having a low effective transmittance by performing VUV treatment, which is a surface modification treatment. Forms layer 24a. About this modified layer 24a, while transmittance | permeability rises, chemical-resistance improves. As a result, a multi-gradation photomask having a small variation in transmittance of the translucent portion in the plane is obtained. Thereafter, the same portion may be subjected to heat treatment, or the entire surface may be subjected to heat treatment.

The transfer pattern of the multi-gradation photomask is transferred to the to-be-processed layer by irradiating the exposure light by an exposure machine using the above-mentioned multi-gradation photomask. In this case, it is preferable to use exposure light containing a wavelength band of i-g line as exposure light. Thereby, the resist pattern of the residual film value of desired thickness can be obtained regardless of a pattern shape in a semi-transmissive area | region.

This invention is not limited to the said embodiment, It can change suitably and can implement. For example, in the said embodiment, although the case where the photomask blank which formed the transflective film and the light shielding film in this order was used on the transparent substrate was demonstrated, after forming a light shielding film pattern on a transparent substrate, it coat | covers a translucent film. And a photomask formed by pattern processing. In addition, the number, size, processing procedure, etc. of the member in the said embodiment are an example, It can change and implement in various ways.

21: transparent substrate
22; Shading
23: antireflection film
24: translucent film
24a: modified layer
25: resist layer

Claims (10)

As a photomask manufacturing method,
Forming a transfer pattern including a semi-transmissive portion by patterning a semi-transmissive film formed on a transparent substrate and transmitting part of the exposure light;
A measurement step of measuring the exposure light transmittance of the plurality of translucent parts included in the transfer pattern;
The exposure light transmittance is changed by performing a surface modification treatment different from the other parts on the semi-transmissive films of the selected portions in the plurality of semi-transmissive sections based on the measurement results.
Photomask manufacturing method. The method of claim 1,
The surface modification treatment includes a process of irradiating a predetermined energy to the translucent film of the selected portion. The method of claim 2,
The said energy irradiation process is vacuum ultraviolet irradiation, The photomask manufacturing method characterized by the above-mentioned. The method of claim 1,
The semi-transmissive film is MoSix, MoSiO, MoSiN, MoSiON or MoSiCON, characterized in that the method of manufacturing a photo mask. The method of claim 1,
The semi-transmissive film comprises a chromium oxide, nitride, carbide, oxynitride or oxynitride carbide. The method of claim 1,
A heat treatment is performed on the entire surface after the surface modification treatment. The method of claim 1,
The said photomask manufacturing method includes the wet process using chemical liquid, The photomask manufacturing method characterized by the above-mentioned. The method of claim 1,
Wet etching is used for the said patterning, The photomask manufacturing method. The pattern transfer method transfers the said transfer pattern to a to-be-processed layer by irradiating the exposure light by an exposure machine using the photomask by the manufacturing method in any one of Claims 1-8. 10. The method of claim 9,
Exposure light containing the wavelength band of i line | wire-g line is used as said exposure light, The pattern transfer method characterized by the above-mentioned.

Images