TWI438562B - Photomask manufacturing method, pattern transfer method, processing apparatus for a photomask substrate, and thin film patterning method - Google Patents

Description

Photomask manufacturing method, pattern transfer method, mask substrate processing device, and film patterning method

The present invention relates to an exposure mask for semiconductor device manufacturing and the like, and more particularly to a method of manufacturing a mask for forming the mask pattern, a pattern transfer method using the mask, and a mask substrate processing apparatus. And film patterning methods.

In general, in the manufacturing steps of an electronic device such as a semiconductor device, transfer of a fine pattern is performed using a photolithography method. Further, in the transfer of the fine pattern, a plurality of substrates called photomasks are usually used. In general, the photomask is provided with a fine mask pattern including a metal thin film on a translucent glass substrate, and a lithography method is also used in the manufacture of the photomask.

In the manufacture of a photomask using a lithography method, a photomask substrate including a film (for example, a light shielding film) for forming a transfer pattern (mask pattern) on a light-transmissive substrate such as a glass substrate is used. The manufacturing of the photomask using the reticle base includes the steps of: drawing a desired transfer pattern for the resist film formed on the reticle substrate; and developing a step of developing the resist film a resist pattern; an etching step of using the resist pattern as a mask and etching the film; and removing the remaining resist pattern by stripping. In the above development step, a developing solution is supplied after performing a desired mask pattern drawing on the resist film formed on the mask substrate to dissolve and remove the portion of the resist film soluble in the developer, thereby forming a resist. pattern. Further, in the etching step, the resist pattern is used as a mask, and a portion of the film in which the resist pattern is not formed is usually removed by dry etching, thereby forming a desired mask pattern. On a light substrate. Thereby completing the mask.

In recent years, the necessity of manufacturing an electronic device including a semiconductor device having a high degree of integration has been increasing. With the demand for miniaturization of electronic device patterns such as semiconductor devices, the necessity of miniaturization of the mask pattern formed on the photomask for manufacturing an electronic device has also increased.

Japanese Patent Publication No. Hei 11-204415 (Patent Document 1) discloses a drawing method for determining an irradiation amount of an electron beam for each irradiation position and suppressing fogging, that is, unnecessary. The amount of exposure caused by the influence of exposure. When an electron beam is used to draw a pattern on the resist film, an irradiation other than the desired electron beam is generated due to the influence of the proximity effect, the reflection of the electron beam irradiated onto the sample substrate, the multiple reflection of the inner wall of the sample, and the like. (Atomization), so that the amount of irradiation in the surface of the sample is distributed. In view of the above, there is disclosed a method of calculating the amount of irradiation caused by the effects of the proximity effect and the atomization, and the actual irradiation amount given to the sample substrate reaches a specific irradiation amount at each irradiation position of the electron beam. The amount of irradiation of the optical system is obtained based on the amount of irradiation calculated above.

Japanese Laid-Open Patent Publication No. Hei 11-288105 (Patent Document 2) discloses a resist pattern forming method for suppressing formation of a poorly soluble layer on the surface of a resist film in order to form a pattern using a positive resist. After the patterning exposure, the positive resist film is subjected to post-exposure baking, and then the resist film is brought into contact with an acidic solution (for example, nitric acid), followed by development processing. The reason why the hardly-melted layer is formed on the surface of the resist film is described in that it is caused by the loss of acid due to the amine in the air in the positive-type resist of the chemical amplification type using the acid generator which uses the action of light. live.

For example, in order to form a reticle pattern for a ultra-fine LSI (Large Scale Integration) device having a half pitch of 45 nm or 32 nm on a photomask, it is generally advantageous to use a high sensitivity and a high level as much as possible. The resist of resolution is formed by forming a fine fine resist pattern by an electron beam, for example, a chemically amplified EB (Electron Beam) resist is preferable. However, the inventors have found that the use of such a high-sensitivity, high-resolution EB resist, particularly in the surface layer portion of the resist, can also be achieved by drawing a small amount of stray light (electrons) generated in the machine. The threshold value of the sensitizing (reaction) energy of the etchant has a tendency to form a resist pattern.

In view of the above problems discovered by the present inventors as described above, for example, the method disclosed in Patent Document 1 adjusts the amount of irradiation of the electron beam used in the drawing in order to reduce the influence of fogging (ie, unnecessary exposure). In the case where the influence of the atomization is too strong, the atomization caused by the area of the maskless pattern cannot be corrected, and therefore, the method of Patent Document 1 alone is not sufficient to solve the above problem.

Further, according to the method disclosed in Patent Document 2, if the nitric acid as the acidic solution is brought into contact with the resist film before the development treatment after the post-exposure baking, the following problem occurs: the nitric acid remaining on the surface may be followed by The developer supplied to the surface of the mask substrate reacts or reacts with a substance such as ammonia in the ambient gas to generate foreign matter such as ammonium nitrate. Such foreign matter may cause defects in the etching step or may be transferred to the transfer target together with the transfer pattern formed on the photomask to produce a defective device. Therefore, it is necessary to prevent foreign matter from being generated. That is, in order to solve the above problem, the method of Patent Document 2 cannot be employed.

Further, the inventors of the present invention have found that when a resist having high sensitivity and high resolution is formed on the ultrafine pattern as described above, a desired resist may not be formed after the development step after the drawing. pattern. Specifically, the present inventors have found a phenomenon in which, for example, when a negative resist is used, in the undrawn region which should be dissolved and removed by development, an anti-dissolution resistance remains on the outermost surface of the resist. The etchant, and thus the resist is attached to the reticle substrate. Originally these resists should be completely dissolved by development. Further, the present inventors have also recognized that the phenomenon of poor dissolution at the time of such development is difficult to occur in a region where only a finer device pattern is arranged in the transfer pattern, and in a relatively large area of the exposed region. In the vicinity of this, such a defect is likely to occur regardless of the area where the fine patterns are arranged.

In view of the above, an object of the present invention is to provide a method of manufacturing a photomask suitable for forming a mask pattern used in an ultrafine LSI device.

Another object of the present invention is to provide a pattern transfer method using the photomask.

Still another object of the present invention is to provide a processing apparatus for a photomask substrate suitable for use in the manufacture of the photomask.

It is still another object of the present invention to provide a film patterning method for patterning a thin film formed on a substrate.

As described above, the inventors of the present invention presumed that the phenomenon of poor dissolution at the time of development is likely to occur in the vicinity of the exposed area of a relatively large area. Therefore, there is a correlation between the distribution in the plane of the drawing energy and the occurrence of the above phenomenon. Further, as described above, the resist which is advantageous for the formation of the ultrafine pattern is designed to have a high resolution, and on the other hand, in order to increase the squareness of the resist pattern, a light beam having a high accelerating voltage is used, so that stray light in the drawing machine is formed. The amount of energy that is incident on the resist is also large. Therefore, the energy that is considered to be an unnecessary exposure (atomization) is increased. Further, it is presumed that the desired transfer pattern is prevented from being correctly formed on the resist film. In addition, the atomization generated in the above drawing means that the energy beam (electron beam) is irradiated onto the mask base of the resist film, and is reflected by the surface of the resist or the surface of the substrate, and further in the drawing machine. Multiple reflections of various surfaces, then sensitizing the resist, or generating secondary electrons or electromagnetic waves on the surface or inside of the reticle base, the secondary electrons and the like are multi-reflected in the drawing machine to sensitize the resist The sensitization of the resist caused by the irradiation of unnecessary energy.

On the other hand, the present inventors further conducted active research and found that the surface layer portion of the resist overlaps with the stray light generated in the drawing machine and is incident on the resist as compared with the surface layer of the resist. The energy of the exposure (atomization) caused by the unnecessary energy, as a result, reaches the threshold of the photosensitive energy of the resist, so that the solubility of the developer relative to the surface layer of the resist changes, and the correct resistance is obtained. The etch pattern formation caused an adverse effect, and the inventors completed the present invention based on this finding.

Various aspects of the invention are listed below.

(Aspect 1) A method of manufacturing a reticle comprising the steps of: preparing a reticle substrate on which a film and a resist film are formed on a substrate; and drawing a desired pattern on the resist film of the reticle base using a drawing machine a transfer pattern; after the drawing, the resist film is developed to form a resist pattern; and the resist pattern is used as a mask and the film is etched; and the resist film is developed after the drawing Previously, a surface treatment was performed in which an oxygen-containing or oxygen-containing oxidizing substance was brought into contact with the surface of the resist film.

(Aspect 2) The method for producing a photomask according to aspect 1, wherein the film is a light-shielding film.

(Aspect 3) The method for producing a photomask according to aspect 1, wherein the oxidizing substance comprises at least one selected from the group consisting of ozone gas, ozone water, hydrogen peroxide gas, and hydrogen peroxide water.

(Aspect 4) A reticle, which is manufactured by the method of manufacturing a reticle according to any one of the aspects 1 to 3.

The method of manufacturing a reticle according to any one of aspects 1 to 3, wherein the surface of the resist film is removed from the surface of the resist film by the surface treatment. The surface layer within.

The method of manufacturing a photomask according to any one of aspects 1 to 3, wherein the resist film is a chemical amplification resist.

The method of manufacturing a photomask according to any one of aspects 1 to 3, wherein the resist film is a negative resist.

The method of manufacturing a photomask according to any one of aspects 1 to 3, wherein the photomask is an exposure machine for using a laser beam having a wavelength of 200 nm or less as an exposure light source.

(Aspect 9) A pattern transfer method using the photomask of the manufacturing method according to any one of the aspects 1 to 3, and transferring the pattern onto the transfer target by an exposure machine.

(Aspect 10) A processing apparatus for a mask substrate, which is used for a processor including a mask substrate on which a resist pattern of a desired transfer pattern is drawn, and includes a stage on which the above-described substrate is placed a reticle substrate; a rotating mechanism that rotationally drives the platform; and an oxidizing substance supply mechanism that contacts the oxidizing substance containing at least one selected from the group consisting of ozone gas, ozone water, hydrogen peroxide gas, and hydrogen peroxide water a surface of the mask substrate on the platform; an eluent supply mechanism; and a control mechanism that controls the rotation mechanism, the oxidizing substance supply mechanism, and the eluent supply mechanism, respectively.

(Aspect 11) The processing apparatus for a photomask substrate according to aspect 10, further comprising a developer supply mechanism that causes the developer to contact the surface of the mask substrate.

(Surface 12) A film patterning method comprising the steps of: preparing a substrate on which a film and a resist film are formed on a transparent substrate; and drawing a desired turn on the resist film of the substrate using a drawing machine a pattern; after the drawing, the resist film is developed to form a resist pattern; and the resist pattern is used as a mask and the film is etched; and the film is formed after the drawing and before the development of the resist film The surface of the surface of the resist film is treated with at least an oxygen-containing oxidizing substance.

According to the present invention, it is possible to provide an ultrafine LSI device having a half pitch of 45 nm, 32 nm or the like without being affected by exposure caused by unnecessary energy incident to the resist at the time of drawing. A method of manufacturing a mask of a cover pattern, and a pattern transfer method using the mask.

Moreover, according to the present invention, it is possible to provide a processing apparatus for a mask substrate which is suitable for use in the manufacture of the photomask of the present invention.

Hereinafter, embodiments of the present invention will be described.

First, a method of manufacturing a photomask according to an embodiment of the present invention will be described. The manufacturing method of the reticle includes the steps of: preparing a reticle substrate on which a light-shielding film and a resist film are formed on a transparent substrate; and drawing a desired transfer pattern on the resist film of the reticle base using a drawing machine After the drawing, the resist film is developed to form a resist pattern; and the resist pattern is used as a mask to etch the film. Further, the method of manufacturing the photomask is characterized in that surface treatment for bringing an oxygen-containing or oxygen-containing oxidizing substance to the surface of the resist film is performed after the above-described drawing and development of the resist film (hereinafter, "Specific surface treatment"). Here, the film having a light-shielding property refers to at least one of the light-shielding exposure light of at least one layer when the exposure light transmittance of the transparent substrate is 100%, and includes a semi-transmissive film. Film of sex.

That is, after performing the desired mask pattern drawing (electron beam exposure) on the resist film of the mask base by the drawing machine and before the development processing, the surface of the resist film is subjected to a specific surface treatment, that is, oxygenation is performed. Or a surface treatment of contacting the surface of the resist film with an oxidizing substance containing oxygen and hydrogen. By this specific surface treatment, the extremely shallow surface layer portion of the resist film is oxidized by the oxidizing substance to dissolve or remove the resist in the surface layer portion.

Fig. 1 is a schematic view for explaining a difference in the influence of exposure (atomization) of unnecessary energy incident on a resist at the time of drawing on the surface portion of the resist and the inside of the resist. A photomask substrate (see FIG. 1(a)) in which a chromium-based light-shielding film 2 and a resist film (negative type) 3 are formed on the transparent substrate 1 (see FIG. 1(a)), and a specific mask pattern is described (see FIG. 1(b). )). Here, line and space patterns of a line width of 1:1 are set.

At this time, when focusing particularly on the non-exposed areas sandwiched between the exposed areas of a large area, the surface layer portion of the resist (refer to FIG. 1(c)) causes unnecessary energy incident at the time of drawing. Under the influence of exposure (atomization), the energy of the light is drawn to reach the threshold of the photosensitive energy of the resist, and the inside of the resist (refer to FIG. 1(f)) is hardly affected by the above-mentioned atomization. The energy that depicts the light does not reach the threshold of the sensitizing energy that makes the resist insoluble. Further, in Figs. 1(c) and 1(f), the solid line indicates the case where the energy of the atomization is included, and the broken line indicates the case where the energy of the atomization is not included.

As a result, when the resist film 3 is subjected to development processing after the drawing, the atomization of the surface portion of the resist affects the formation of the resist pattern, so that the non-exposed area (the area of A) sandwiched between the exposed areas of the large area described above The resist is not resolved and the resist remains, and as a result, the resist pattern 3a is formed (see FIG. 1(d)).

On the other hand, in order to prevent the atomization of the surface layer portion of the resist from affecting the subsequent formation of the resist pattern, the surface portion 5 of the resist film is removed by performing a specific surface treatment after the drawing (refer to FIG. 1). (e)), and then developing the resist film 3, according to the photographic light energy distribution shown in FIG. 1(f), the non-exposed area (area of A) sandwiched between the exposed areas forming the large area described above is also obtained. The resist pattern 3b is resolved (see Fig. 1(g)). Therefore, the influence of exposure (atomization) caused by an unnecessary light beam generated at the time of drawing can be avoided, so that the desired desired transfer pattern can be formed correctly on the resist film.

The oxidizing substance used in the specific surface treatment is an oxidizing substance containing oxygen or containing oxygen and hydrogen. Specifically, it is preferably exemplified to contain water selected from the group consisting of ozone gas, ozone water, hydrogen peroxide gas, and hydrogen peroxide. At least one of the substances. The oxidizing substance to be used is a substance which does not have any foreign matter remaining on the surface of the mask after remaining after the specific surface treatment. For example, when an acid such as sulfuric acid, hydrochloric acid, nitric acid or phosphoric acid is used, the acid remaining after the treatment may react with the developer to produce a product, or may be generated by contact with an ambient gas of ammonia gas in the ambient gas. Foreign matter such as ammonium salt. When such foreign matter adheres to the developed photomask, it acts as a mask during etching to cause defects in the etching pattern. Further, if the acid remaining after the development treatment is not completely removed by the subsequent mask cleaning, it is generated on the surface of the mask due to the exposure energy at the time of device manufacture and the ammonia gas in the mask or the surrounding environment gas. The shackles of foreign bodies. The foreign matter is transferred to the transfer target together with the transfer pattern formed on the mask as a defect, and the risk of manufacturing a defective device is high.

As the oxidizing substance, ozone water is particularly preferable. Ozone water is obtained by dissolving ozone in pure water, and it is preferably used in an amount of 10 to 100 ppm, more preferably 10 to 50 ppm. When the concentration is less than 10 ppm, the effect of the specific surface treatment cannot be sufficiently obtained. On the other hand, if the concentration is too large, the effect cannot be improved, and if it exceeds 100 ppm, the film of the resist film is reduced to increase. Thus, when the concentration is fixed above, the defect is caused, and the relationship between the concentration of the ozone water and the amount of the dissolved solvent changes depending on the process conditions before the resist or ozone water treatment used, and thus It is determined by considering the amount of the resist surface layer dissolved. Further, since ozone water is a liquid and is subjected to the same wet treatment as the development step, it has an advantage that handling in the same processing apparatus is easy. Moreover, ozone water also has the advantage of easy disposal of waste liquid.

Further, it can also be used in ozone water to dissolve carbon dioxide.

As will be described later, the ozone water containing carbon dioxide can uniformly dissolve the surface of the resist film on the entire surface of the substrate. Further, a person who adds a suitable surfactant to ozone water can also be used. The surface of the resist is generally hydrophobic, so that ozone water uniformly wets the resist under the effect of the surfactant when the ozone water contacts the resist film, so that the treatment uniformity of the ozone water treatment itself is improved.

Preferably, by a specific surface treatment, from the extremely shallow surface portion of the resist film, for example, the surface, the film thickness direction is 100. The surface layer inside is partially dissolved or removed. Better is 30~80 The surface layer is partially removed. Regarding the thickness of the preferred removed portion, the distance of the energy of the electron beam caused by the atomization into the resist film can be considered. Further, the removed portion may be considered in advance, and the thickness of the resist film applied to the mask substrate may be increased to the extent corresponding to the removed portion.

The specific surface treatment is performed after the resist film of the reticle base is subjected to the desired reticle pattern drawing by the drawing machine and before the development process, but after the drawing is performed, it is called post-exposure- In the baking treatment of Bake), it is preferred to carry out a specific surface treatment after the post-exposure baking treatment and before the development treatment. Further, in this manner, since the surface of the resist is oxidized, an advantageous effect is also obtained in terms of improving wettability with respect to the water-soluble developing solution. Further, in the case of performing a specific surface treatment by a liquid, it is not necessary to insert a drying treatment between the specific surface treatment and the development treatment, and thus it is efficient.

Furthermore, it is also possible to perform rinsing as needed after a specific surface treatment.

As the resist film, a chemically amplified resist is preferred. In other words, the above problem is likely to occur when a resist for electron beam exposure suitable for formation of an ultrafine resist pattern, that is, a case where the sensitivity and the resolution are high, are used, and the effect is remarkably exhibited.

Further, as the resist, both the positive resist and the negative resist can be effectively utilized. In the case of a positive resist, excessive exposure is caused to the surface of the resist film by unnecessary exposure (atomization) generated during drawing, and the shape of the resist pattern is deteriorated by development ( Specifically, the corner portion of the resist pattern is rounded. However, since the surface is removed by performing a specific surface treatment before development, deterioration of the shape of the resist pattern can be prevented. Moreover, the resist of the undrawn portion causes a decrease in the film corresponding to the energy of the atomization after development, which may hinder the normal formation of the resist pattern, but if a specific surface treatment is performed by the development before the inclusion, The entire resist surface layer on the substrate on which the film is reduced is removed, so that the resist pattern can be formed normally and defects can be prevented from occurring. On the other hand, in the case of a negative resist, as described above, a portion which is poorly dissolved during development is formed on the surface of the resist film by atomization generated during drawing, but A specific surface treatment is performed to remove the portion, so that a good resist pattern can be formed. In the case of either a positive type or a negative type, it is possible to form an anti-corrosion caused by unnecessary exposure of the surface layer portion of the resist film by atomization generated during drawing by a specific surface treatment. Since the latent image layer portion (photosensitive portion) is removed, a good resist pattern shape can be accurately formed on the resist film.

In particular, in the case of using a negative resist, the effect of the specific surface treatment is particularly remarkable for the development of the poorly-dissolved layer which is generated in the surface layer portion of the resist film by atomization exposure.

Further, when a specific surface treatment is performed using an oxidizing substance of a liquid such as ozone water, an appropriate surfactant for improving the wettability with the oxidized substance and promoting uniform treatment can be previously attached to the resist. on.

After the drawing, the specific surface treatment described above is performed, and then the development processing of the resist film is performed. For example, when a specific surface treatment is subjected to a wet treatment using an oxidizing substance such as an ozone-like liquid, it is preferable to carry out the lowering of the surface of the resist film after the completion of the specific surface treatment. A developer is exposed to the development process of the resist film surface. For example, after performing a specific surface treatment, it is preferred to bring the developer into contact with the resist film within about 10 minutes, and more preferably within 5 minutes, which improves the wettability with the developer, and thus good.

According to the discussion of the present inventors, it has been found that the specific surface treatment not only has the effect of removing the photosensitive portion of the surface layer of the resist film caused by unnecessary exposure (atomization) generated at the time of drawing, but also has a hydrophilicity. The high-resistance of the resist surface is exposed to obtain an effect of improving the wettability with the developer and uniformizing the development reaction in the substrate surface.

Fig. 2 is a graph showing the temporal change of the contact angle of the surface of the resist after the specific surface treatment. According to the graph, the contact angle of the surface of the resist increases with time after the specific surface treatment, and the state in which the hydrophilicity is high after the specific surface treatment is gradually changed to the state of being hydrophobic. Furthermore, Ref in FIG. 2 is the contact angle of the resist surface of the substrate before the step. Therefore, in order to effectively utilize the effect of making the hydrophilicity of the specific surface treatment high and the surface of the new resist exposed, it is preferred that the surface of the resist after the specific surface treatment is not dried and the development process is rapidly performed. .

The present invention can also provide a pattern transfer method characterized by using a photomask obtained by the above-described manufacturing method and transferring the pattern onto the object to be transferred by an exposure machine.

As the photomask, a photomask used in an exposure machine using, for example, a KrF excimer laser (wavelength: 248 nm), an ArF excimer laser (wavelength: 193 nm), or the like as an exposure light source is preferably used. In particular, it is preferable to use a photomask which is used as an exposure light source for laser light having a wavelength of 200 nm or less in an ArF excimer laser which is advantageous for pattern transfer of an ultrafine pattern having a half pitch of 45 nm or 32 nm.

The mask is, for example, a binary mask including a light-shielding film pattern of a chromium-based material on a transparent substrate, or a material containing a transition metal halide-based compound (for example, molybdenum telluride) on the transparent substrate. A binary mask of a light-shielding film mask pattern.

Further, the light-shielding film at this time may be a light-transmissive film which is used in comparison with the exposed portion of the transparent substrate, and includes a semi-transparent film.

The transfer pattern formed on the photomask may include, for example, a fine mask pattern having a mask pattern line width of less than 1 μm, and a line width of 100 times or more (preferably 1000 times or more) of the fine pattern or a mask. The surrounding pattern of the pattern area. When there is a difference in the size of the mask pattern in such a transfer pattern, the previous problem easily occurs, and the above problem can be solved according to the manufacturing method of the mask including the specific surface treatment, and the intended place can be The desired transfer pattern is correctly formed on the resist film, so that a remarkable effect can be exerted.

Furthermore, a hard mask process may be employed in which the resist pattern on the underlying layer of the resist is patterned by using the resist pattern on the mask substrate as a mask, and the pattern of the sacrificial layer is used as a mask. The mask is patterned with a light-shielding film located under the sacrificial layer. Alternatively, a resist pattern in a multilayer resist process can also be used. In the case of a pattern forming process using a photomask having such a sacrificial layer, the entire processed multilayer film under the resist is referred to as a light-shielding film.

Further, in the case where the light-shielding film at the time of mask formation has a film having an anti-reflection function or the like with respect to exposure light, or a film for protecting the light-shielding film is used in the upper layer at the time of manufacture or use of the reticle In the case where the mask base is patterned, the entire patterned multilayer film including the antireflection film and the protective film is referred to as a light-shielding film. Further, it is also known that a photomask for providing a conductive film between a light shielding film and a substrate in order to prevent pattern charge during etching, or a photomask for providing a film for protecting a film or a substrate itself under the light shielding film, and the above The multilayer film is similarly referred to as a light-shielding film as a whole.

Further, it is also possible to use a photomask manufactured by using a mask base provided with an absorption film on the substrate after the film is not subjected to the patterning process. As such a mask, a reflective mask used in EUV (Extreme Ultraviolet) exposure (exposure wavelength: 13.5 nm) or the like is known, and it is known to alternately use a molybdenum layer in order to efficiently reflect exposure light. The present invention can also be practiced for a reticle in which a multilayer film of a ruthenium layer is provided on a substrate and an absorbing film provided on the multilayer film is patterned. At this time, the substrate may be transparent or opaque to the exposure light when the reticle is used. The reticle used in EUV exposure generally requires a finer reticle pattern than the transmissive reticle. Therefore, for the patterned layer, a multilayer resist process or hard light is often used. The process of the mask manufacturing process can of course also be carried out for the manufacturing method of such a mask.

Moreover, the present invention can be carried out as a patterning method of a film other than a photomask formed on a substrate.

In this case, the thin film patterning method of the embodiment includes the steps of: preparing a substrate on which a processed film and a resist film are formed on a transparent substrate; and drawing a desired transfer pattern on the resist film of the substrate using a drawing machine After the drawing, the resist film is developed to form a resist pattern; and the resist pattern is used as a mask to etch the film. Further, the film patterning method is characterized in that a specific surface treatment for bringing an oxygen-containing or oxygen-containing oxidizing substance to the surface of the resist film is performed after the above-described drawing and development of the resist film.

Moreover, the present invention can also be implemented as a processing apparatus which is preferably applied to the manufacture of the photomask, that is, a photomask used in the process of including a photomask substrate on which a resist film having a desired transfer pattern is drawn. The substrate is processed by a processing device.

In this case, the processing apparatus for a photomask substrate according to the embodiment is characterized by comprising: a stage on which the mask substrate is placed; a rotating mechanism that rotationally drives the stage; and an oxidizing substance supply mechanism that is selected from the group consisting of ozone gas An oxidizing substance of at least one of ozone water, hydrogen peroxide gas, and hydrogen peroxide water contacts a surface of the photomask substrate placed on the platform; an eluent supply mechanism; and a control mechanism that controls the rotation The mechanism, the oxidizing substance supply mechanism, and the eluent supply mechanism. The processing apparatus for the photomask substrate preferably further includes a developer supply mechanism that brings the developer into contact with the surface of the mask substrate.

The processing apparatus can perform the specific surface treatment and development processing described in the above-described method of manufacturing the mask for the painted mask substrate (mask base). According to the processing apparatus described above, after the specific surface treatment is performed by the control means by supplying an oxidizing substance (for example, ozone water), the supply of the developing solution is started immediately, and the developing step is started, and after the specific surface treatment is performed, The development step is initiated via a rinse step of the eluent supply. In any of the above cases, it is preferable that the surface of the substrate (resist film surface) is maintained in a state in which it is not dried during the period from the supply of the oxidizing material to the supply of the developer. Further, the control means can arbitrarily control the time until the specific surface treatment for supplying the oxidized material is completed, and then the drying process is performed by the rinsing process until the development process of the supply of the developer is started. For example, after the completion of the specific surface treatment, the start of the development step may be preferably a fixed time of 10 minutes or less, more preferably 5 minutes or less.

Next, the above-described processing apparatus for a mask substrate will be further described in detail with reference to FIG. 3.

Fig. 3 shows a processing apparatus for a photomask substrate suitable for the manufacture of a photomask substrate. The processing apparatus for a photomask substrate is suitable for a specific surface treatment and development treatment, and ozone water is used as an oxidizing substance used in a specific surface treatment.

The processing method in the processing apparatus for the reticle substrate is a processing method in which the object to be processed is rotated while being processed, and the mask substrate as the object to be processed (the reticle base on which the drawing has been completed) can be rotated. The ozone water of the treatment liquid is supplied onto the surface of the resist of the photomask substrate, and the ozone water diffused by the rotation dissolves the entire resist surface of the photomask substrate, and then is rinsed by water washing to supply the developer. After the surface of the resist which is dissolved in the surface layer and the hydrophilicity is improved, after the resist pattern is formed, the developer is rinsed and subjected to centrifugal dehydration drying.

The processing apparatus for the reticle substrate includes a processing container 11 in which the entire upper surface opening is formed into a substantially bowl shape, and a plurality of exhaust liquid discharge ports 20 are formed in the bottom wall of the processing container 11.

Below the processing container 11, a motor 16 is disposed concentrically with the encoder 15 and the processing container 11. The rotating shaft 14 of the motor 16 is inserted into the inside of the processing container through the bottom wall of the processing container 11. The motor 16 is configured to be disposed on the upper surface of the platform 17 on the elevator 19, and is movable up and down via the stroke shaft 18 of the elevator 19. Further, the rotary head 12 that holds the mask substrate 10 as the substrate to be processed on the end surface portion is supported by the upper end portion of the rotary shaft 14 of the motor 16 so as to rotate in a horizontal arrangement. In other words, the rotary head 12 is configured to be in contact with the end surface portion of the mask substrate 10 to be integrally rotated.

On the other hand, above the processing container 11, a liquid supply nozzle 28 for supplying ozone water as a processing liquid is vertically disposed downward, and the liquid supply nozzle 28 is lifted and lowered by a suitable driving mechanism (not shown). And move horizontally. An ozone water supply unit 27 is connected to the liquid supply nozzle 28, and an ozone water generating unit 26 is connected to the ozone water supply unit 27. The ozone water supply unit 27 is configured to supply a specific amount of ozone water at a specific amount at a specific time.

Further, similarly above the processing container 11, a liquid supply nozzle 33 for supplying an eluent such as pure water is disposed vertically downward. The liquid supply nozzle 33 for supplying the eluent is also moved up and down and horizontally by an appropriate drive mechanism (not shown). The eluent supply unit 32 is connected to the liquid supply nozzle 33. The eluent supply unit 32 is configured to supply a specific amount of eluent such as pure water at a specific time.

Further, similarly above the processing container 11, a liquid supply nozzle 31 for supplying a developing solution is disposed vertically downward. The liquid supply nozzle 31 for supplying the developer is also moved up and down and horizontally moved by a suitable driving mechanism (not shown). The developer supply unit 30 is connected to the liquid supply nozzle 31. Further, a developer accumulating tank 29 is connected to the developer liquid supply unit 30. The developer supply unit 30 is configured to supply a specific amount of developer at a specific time.

As the apparatus for producing ozone water used in the above-described ozone water generating device 26, an apparatus for obtaining ozone gas by oxygen discharge obtained by electrolysis of water or the like, and passing it through a dissolution membrane or the like can be used. Ozone water is obtained by a method (not shown) in which it is dissolved in contact with pure water.

Further, in the apparatus for supplying ozone water into the inside of the processing container and the piping thereof, the liquid supply pipe is branched in the vicinity of the liquid supply nozzle, thereby causing ozone water to be dissolved in the ozone water between the ozone water generating device 26 and Circulation between the branch portions in the vicinity of the liquid supply nozzle, thereby suppressing the self-decomposition of the ozone water in the liquid supply pipe to lower the concentration, and controlling the ozone concentration at the outlet portion of the ozone water generating device 26 to a fixed concentration, thereby being able to always A fixed concentration of ozone water is supplied into the processing container 11. Furthermore, it is preferable to provide a mechanism for discharging ozone water to the processing container at a fixed time before the start of the specific surface treatment, thereby accumulating the ozone from the branching portion between the liquid supply nozzles and reducing the concentration due to self-decomposition. The water is replaced by a liquid of a concentration before decomposition.

Further, it is preferable that the ozone water contains carbonic acid gas dissolved water. In the case of ozone water, since the self-decomposition speed is faster when it comes into contact with the resist, the liquid supply nozzle is disposed even directly above the center of the mask substrate, and the processing liquid is covered on the entire surface of the substrate by the rotation of the substrate. In this case, the phenomenon that the dissolution rate of the resist in the central portion of the substrate is accelerated is also likely to occur. On the other hand, in order to uniformly dissolve the resist on the entire surface of the photomask substrate, it is preferred that the resist contact portion in which the ozone water is dropped contains carbon dioxide as a substance for suppressing the decomposition rate thereof. A device for dissolving water in a carbonic acid gas can be used as a device for dissolving water by using a gas cylinder and dissolving it in contact with pure water via a dissolving film or the like in the same manner as the ozone gas (not shown). Wait.

Further, the mask substrate as the workpiece is carried into the upper portion of the processing container 11 by a loading device (not shown). Further, the processed photomask substrate is carried out by an unloading device (not shown).

Further, an exhaust gas discharge pipe 21 is connected to the exhaust gas discharge port 20 which is opened in the bottom wall of the processing container 11. The exhaust gas 22, the developer waste liquid 23, the ozone water waste liquid 24, and the eluent liquid waste liquid 25 are discharged through the exhaust liquid discharge pipe 21, respectively.

Next, the operation of the above-described processing apparatus for a mask substrate will be described.

The mask substrate 10, which has been subjected to the drawing and the post-exposure baking process, is placed on the rotary table of the rotary head 12 in the processing container 11 by the loading device. Then, while the photomask substrate 10 held by the rotary head 12 is rotated by the motor 16, the liquid supply nozzle 28 supplies ozone water to the surface of the resist 3 on the upper surface thereof. The ozone water supplied onto the mask substrate 10 is uniformly diffused on the entire surface of the mask substrate by the rotation of the mask substrate 10 and the surface tension of the liquid, and is in contact with the surface of the resist 3. At this time, when the liquid supply nozzle 28 is horizontally moved, the contact position of the ozone water supplied from the liquid supply nozzle 28 and the resist on the photomask substrate 10 can be continuously changed, so that the resist on the photomask substrate dissolves more. Uniformly carried out.

After the specific surface treatment using the ozone water, pure water is supplied from the liquid supply nozzle 33 to the photomask substrate, and the substrate is rotated while being rotated.

Then, while the photomask substrate is rotated by the motor 16, the developer liquid is supplied to the upper surface thereof by the liquid supply nozzle 31. The developer supplied onto the mask substrate is uniformly diffused to the entire surface of the mask substrate by the rotation of the mask substrate and the surface tension of the liquid, and is in surface contact with the resist. Since the wettability of the resist surface is preliminarily improved by the specific surface treatment of ozone water, the contact between the developer and the resist surface is preferably performed. At this time, if the liquid supply nozzle 31 is horizontally moved, the contact position between the developer supplied from the liquid supply nozzle and the resist on the mask substrate can be continuously changed, so that development on the mask substrate (resist dissolution) More uniform.

After the supply of the developer is continued for a predetermined period of time, the substrate is rotated by supplying the pure water to the mask substrate from the liquid supply nozzle 33, whereby the developer of the entire surface of the mask substrate is rinsed with pure water or the like. .

After the water washing is performed for a specific period of time, the supply of the pure water is stopped, and the spin coating substrate is dried by performing a suitable spin-drying operation. The dried photomask substrate is unloaded after the rotation operation is stopped.

Furthermore, when the wettability of the resist is poor for a liquid for a specific surface treatment (for example, ozone water), a so-called pre-preparation of contacting the pure water with the surface of the resist may be performed before the specific surface treatment. Wet treatment, or adding a surfactant to ozone water or the like to increase the hydrophilicity of the surface of the resist in advance. As another method for increasing the hydrophilicity of the surface of the resist in advance, a method of exposing the surface of the resist to ozone gas, a method of ashing the surface of the resist, and irradiating the surface of the resist may be used. Dry treatment such as ultraviolet light method.

In the above-described processing method for the photomask substrate, the above-described rotation method is employed. However, the present invention is not limited thereto, and the treatment substrate may be immersed in the treatment liquid for treatment.

Further, the processing apparatus includes both the ozone water supply mechanism and the developer supply mechanism, and the specific surface treatment and development processing are continuously performed by the wet processing in the same apparatus, but may be used after the specific surface treatment. The development processing is performed by another development processing device.

The present invention is not limited to a photomask, and can be applied to patterning of a thin film directly drawn by an electron beam when an electronic device such as a semiconductor wafer or a micromachine is fabricated.

Hereinafter, the examples and comparative examples will be further specifically described.

(Example)

A reticle substrate is prepared by using a synthetic quartz glass substrate having a size of 6 吋 square and a thickness of 0.25 Å as a transparent substrate, and forming a chrome-plated chrome-based system on the synthetic quartz glass substrate by sputtering. a metal film on which a chemically amplified negative resist for electron beam drawing is applied and prebaked to form a film thickness of 2000 Resist film.

Then, a mask pattern is drawn by a drawing device using a variable beam forming method in which an electron beam having an acceleration voltage of 50 kV is used as an energy beam. The drawing pattern is a light-shielding pattern (a mask pattern for a device) having a line width of 0.5 to 2 μm, and a light-shielding pattern (peripheral pattern) having a line width of 1 to 2 mm disposed around the region. Further, the mask pattern for the above device includes line and space patterns having a line width of 1 μm.

The mask base (mask substrate) which was described above was subjected to post-exposure baking using a hot plate.

The mask substrate is placed on a rotary table on the rotary head of the photomask substrate processing apparatus.

Then, the mask substrate was rotated at 200 rpm, and 40 ppm of ozone water was supplied to the resist surface, and the entire surface was uniformly covered. The surface layer portion of the resist is dissolved and removed by subjecting the ozone water to contact with the resist for 10 seconds to perform a specific surface treatment. about. By the dissolution of the surface layer portion of the resist, the surface layer portion which is difficult to be developed and dissolved by the atomization at the time of drawing is removed, and the hydrophilic surface is high and the surface of the new resist is exposed.

The surface of the resist which has been subjected to the specific surface treatment is rinsed with pure water, followed by development treatment using an alkaline developing solution containing an aqueous solution of tetramethylammonium hydroxide. This is carried out by appropriately rotating the substrate during development. After the development treatment, the water is rinsed with pure water to form a resist pattern.

Further, the development processing time at this time was set to 60 seconds, and the above-described drawing was previously adjusted in such a manner that the line of 1 μm after the etching and the line and space patterns were 1:1 line width. Miscellaneous.

Then, the formed resist pattern is plasma-etched as a mask, and the chromium-based metal film is patterned, and then the unnecessary resist pattern is removed by ashing, thereby producing a light-shielding layer containing a chromium-based film. Patterned hood.

(Comparative example)

In the comparative example, the surface treatment of the ozone water to be performed on the surface of the resist after the above-described embodiment was not performed, and the mask substrate was processed in the same manner as in the above-described embodiment to prepare a photomask.

In order to compare the line widths of the reticle pattern patterns formed in the above-described embodiments and the comparative examples, and to perform defect inspection, no defects were detected in the masks produced in the examples, and the defects were produced in the comparative example. In the photomask, a plurality of black defects are detected in the vicinity of a large-area mask pattern having a line width of more than 1 mm. The reason for this is that in the photomask of the comparative example, in the vicinity of the large-area exposure portion in the resist pattern after development due to the atomization generated during the drawing, a resist which is difficult to be developed and dissolved and which is atomized remains.

1. . . Transparent substrate

2. . . Light-shielding film

3. . . Resist film

3a, 3b. . . Resist pattern

4. . . Depicting

5. . . Surface portion of the resist film

10. . . Photomask substrate

11. . . Processing container

12. . . Rotating head

13. . . pin

14. . . Rotary axis

15. . . Encoder

16. . . motor

17. . . platform

18. . . Stroke axis

19. . . elevator

20. . . Exhaust drain

twenty one. . . Exhaust drain piping

twenty two. . . Exhaust gas

twenty three. . . Developer waste

twenty four. . . Ozone water waste

25. . . Eluent waste

26. . . Ozone water generating device

27. . . Ozone water supply unit

28. . . Liquid supply nozzle for supplying ozone water as a treatment liquid

29. . . Developer tank

30. . . Developer liquid supply unit

31. . . Liquid supply nozzle for supplying developer

32. . . Eluent supply unit

33. . . Liquid supply nozzle for supplying eluent such as pure water

A. . . region

1(a) to (g) are diagrams for explaining a difference in the influence of atomization on the resist surface portion and the inside of the resist due to the drawing;

Figure 2 is a graph showing the temporal change of the contact angle of the surface of the resist after surface treatment;

Fig. 3 is a view showing the configuration of a processing apparatus for a mask substrate according to an embodiment of the present invention.

1. . . Transparent substrate

2. . . Light-shielding film

3. . . Resist film

3a, 3b. . . Resist pattern

4. . . Depicting

5. . . Surface portion of the resist film

A. . . region

Claims (15)

A method for manufacturing a reticle, comprising the steps of: preparing a reticle substrate on which a film and a resist film are formed on a substrate; and drawing a desired transfer pattern on a resist film of the reticle substrate using a drawing machine; After the drawing, the resist film is developed to form a resist pattern; and the resist pattern is used as a mask to etch the film; and the film is formed after the drawing and before the development of the resist film. Oxygen or an oxidizing substance containing oxygen and hydrogen is in contact with the surface of the surface of the resist film; the surface treatment is performed by removing the surface layer portion within 100 Å of the film thickness direction from the surface of the resist film. A method of producing a photomask according to claim 1, wherein the film is a light-shielding film. The method of producing a photomask according to claim 1, wherein the oxidizing substance comprises at least one selected from the group consisting of ozone gas, ozone water, hydrogen peroxide gas, and hydrogen peroxide water. The method of producing a photomask according to claim 3, wherein the oxidizing substance is ozone water in which ozone is dissolved in a concentration of 10 to 100 ppm in pure water. The method of manufacturing a photomask according to claim 1, wherein the surface layer of the film thickness direction of 30 to 100 Å is removed from the surface of the resist film by the surface treatment. The method of manufacturing a reticle according to any one of claims 1 to 5, wherein The etching film is a chemically amplified resist. The method of manufacturing a photomask according to any one of claims 1 to 5, wherein the resist film is a negative resist. The method of manufacturing a photomask according to any one of claims 1 to 5, wherein the photomask is used as an exposure machine for exposing laser light having a wavelength of 200 nm or less. The method of manufacturing a photomask according to claim 2, wherein the light-shielding film comprises a sacrificial film and a light-shielding film. The photomask manufacturing method according to any one of claims 1 to 5, wherein the photomask comprises a fine mask pattern having less than 1 μm and a peripheral pattern having a line width of 100 times or more of the fine pattern. The method of manufacturing a reticle according to any one of claims 1 to 5, wherein after the step of etching the film, the step of removing the resist pattern which is unnecessary is included. The method of manufacturing a photomask according to any one of claims 1 to 5, wherein the step of drawing the transfer pattern is performed using an electron beam drawing machine. A reticle, which is manufactured by the method of manufacturing a reticle according to any one of claims 1 to 5. A pattern transfer method using the photomask of the manufacturing method according to any one of claims 1 to 5, and transferring the pattern onto the object to be transferred by an exposure machine. A film patterning method comprising the steps of: preparing a substrate on which a processed film and a resist film are formed on a transparent substrate; Depicting a desired transfer pattern on the resist film of the substrate using an electron beam drawing machine; developing the resist film to form a resist pattern after drawing; and using the resist pattern as a mask and etching the film And characterized in that after the above-described drawing and development of the resist film, surface treatment is performed to bring an oxygen-containing or oxygen-containing oxidizing substance to the surface of the resist film, thereby removing the surface of the resist film. The surface portion within 100 Å of the film thickness direction.