WO2023199659A1

WO2023199659A1 - Resist material, method for producing resist pattern, and resist pattern

Info

Publication number: WO2023199659A1
Application number: PCT/JP2023/009016
Authority: WO
Inventors: 公男吉村; 亮出崎; 洋揮山本; タンフンヂン; 雅彦石野; 将元錦野; 康成前川; 孝弘古澤
Original assignee: 国立研究開発法人量子科学技術研究開発機構
Priority date: 2022-04-15
Filing date: 2023-03-09
Publication date: 2023-10-19
Also published as: TW202349115A

Abstract

For the purpose of providing a photoresist material having strong resistance to dry etching, this photoresist material according to one embodiment of the present invention is for use in extreme-ultraviolet lithography and comprises a metal oxide precursor or a polymer alloy containing at least one from among polycarbosilanes, polysiloxanes, polysilazanes, and polyorganoborosilazanes.

Description

Resist material, resist pattern manufacturing method, and resist pattern

The present invention relates to a resist material, a method for manufacturing a resist pattern, and a resist pattern.

Photolithography is widely used in which a photomask is two-dimensionally patterned with areas that transmit light and areas that do not transmit light, and the pattern of the photomask is transferred to a photoresist layer.

The fineness of the pattern that can be transferred using photolithography depends on the wavelength of the light used for exposure. Theoretically, the shorter the wavelength of the light used for exposure, the finer the pattern can be transferred to the photoresist layer. Therefore, when attempting to transfer a pattern as fine as possible using photolithography, ultraviolet rays (for example, wavelengths of 193 nm, 248 nm, etc.) are often used as light for exposure. Such photolithography is called ultraviolet (UV) lithography. The width of a thin line that can be transferred using UV lithography is, for example, 18 nm (see, for example, Patent Document 1).

Japanese Patent Application Publication No. 2021-21953 Japan Special Table No. 2017-526171

Additionally, electron beam (EB) lithography has become popular as a form of lithography different from photolithography. In EB lithography, an electron beam having a shorter wavelength than ultraviolet light (for example, a wavelength of 1 nm) is used to expose a resist layer. In EB lithography, the resist layer is exposed by irradiating the resist layer with a focused electron beam while scanning it in a desired pattern. The width of a thin line that can be drawn using EB lithography is, for example, 10 nm (see, for example, Patent Document 2).

In this way, when EB lithography is used, a high-definition pattern can be drawn on the resist layer. However, since exposure is performed by scanning an electron beam, EB lithography has a problem in that exposure takes time.

Therefore, extreme ultraviolet (EUV) lithography, which exposes a photoresist layer using light called extreme ultraviolet rays or soft X-rays (for example, a wavelength of 13.5 nm), is becoming popular (for example, see Non-Patent Document 1). . In EUV lithography, a photoresist layer can be exposed using a photomask while using light with a shorter wavelength than in UV lithography. Therefore, a pattern with higher definition than UV lithography can be obtained with a shorter exposure time than EB lithography.

By the way, the higher the definition of the photoresist layer or the pattern to be transferred to the resist layer, the thinner the thickness of the photoresist layer or resist layer is. It is required to have high dry etching resistance (also called dry etching resistance). Photoresist materials, which are currently widely used, are converted into a resist pattern made of polymer resin through an exposure process and a development process. The dry etching resistance of resist patterns made of polymer resins is generally low.

One aspect of the present invention has been made in view of the above-mentioned problems, and its purpose is to provide a resist material that has high dry etching resistance. Another object of the present invention is to provide a method for manufacturing a resist pattern using such a resist material, and a resist pattern.

In order to solve the above problems, a photoresist material according to one embodiment of the present invention is a photoresist material for extreme ultraviolet lithography, and is one of polycarbosilane, polysiloxane, polysilazane, and polyorganobolosilazane. Contains a polymer alloy containing at least one of these or a metal alkoxide.

In order to solve the above problems, a method for manufacturing a resist pattern according to one embodiment of the present invention uses a polymer alloy containing at least one of polycarbosilane, polysiloxane, polysilazane, and polyorganobolosilazane, or A coating step of applying a resist material containing a metal alkoxide onto a substrate, an exposure step of bringing a photomask close to the substrate coated with the resist material and exposing the resist material, and developing the exposed resist material. A developing step.

In order to solve the above problems, a resist pattern according to one embodiment of the present invention is an amorphous film made of at least one of silicon carbide, silicon dioxide, silicon nitride, and borosilicon carbonitride, It consists of an amorphous film patterned two-dimensionally.

According to one aspect of the present invention, a resist material having high dry etching resistance can be provided. Furthermore, it is possible to provide a method for manufacturing a resist pattern using such a resist material, and a resist pattern.

7 is a flowchart of a resist pattern manufacturing method M10 according to Embodiment 3 of the present invention. 7 is a flowchart of a resist pattern manufacturing method M20 according to Embodiment 4 of the present invention. FIG. 7 is a diagram showing a resist pattern 1 according to Embodiment 5 of the present invention. FIG. 3 is a diagram showing a sensitivity curve created by measuring the film thickness of the remaining pattern in the samples of Examples 1 and 2 that were subjected to EB irradiation or EUV irradiation. (a) is the sensitivity curve of Example 1 with EB irradiation, (b) is the sensitivity curve of Example 2 with EB irradiation, (c) is the sensitivity curve of Example 1 with EUV irradiation, (d) is The sensitivity curve of Example 2 subjected to EUV irradiation is shown. FIG. 7 is a diagram showing a sensitivity curve created by measuring the film thickness of the remaining pattern in the samples of Examples 3 to 5 that were subjected to EB irradiation or EUV irradiation. (a) is the sensitivity curve of Example 3 with EB irradiation, (b) is the sensitivity curve of Example 4 with EB irradiation, (c) is the sensitivity curve of Example 5 with EB irradiation, (d) is (e) shows the sensitivity curve of Example 3 subjected to EUV irradiation, (e) shows the sensitivity curve of Example 4 subjected to EUV irradiation, and (f) shows the sensitivity curve of Example 5 subjected to EUV irradiation. FIG. 3 is a diagram showing a resist film before and after firing conversion. (a) shows the appearance of the resist film of Example 2 before and after the firing conversion, (b) shows the appearance of the resist film of Example 3 before and after the firing conversion, and (c) shows a comparison before and after the firing conversion. The state of the resist film of Example 1 is shown. FIG. 3 is a diagram showing the etching resistance of Example 2 after development or baking conversion, and Comparative Example 1 after coating. FIG. 3 is a diagram showing the etching resistance of Examples after development or baking conversion, and Comparative Examples after coating. (a) is the etching resistance of Example 3 and Comparative Examples 1 to 4, (b) is the etching resistance of Example 4 and Comparative Examples 1 to 4, and (c) is Example 5 and Comparative Examples 1 to 4. shows etching resistance. A resist pattern of Example 2 produced by irradiating pulsed EUV is shown. A resist pattern of Example 5 produced by irradiating pulsed EUV is shown.

[Embodiment 1]
<Photoresist material>
The photoresist material according to Embodiment 1 of the present invention is a photoresist material for extreme ultraviolet lithography, and includes a polymer alloy containing at least one of polycarbosilane, polysiloxane, polysilazane, and polyorganoborosilazane. include. In the photoresist material according to the present embodiment, silicon carbide or the like is converted into a ceramic by crosslinking or firing conversion by irradiation with extreme ultraviolet rays. Therefore, by exposing the photoresist material according to this embodiment to extreme ultraviolet rays, a resist pattern made of ceramics such as silicon carbide can be obtained.

A resist pattern made of ceramics such as silicon carbide has higher density and hardness than a resist pattern made of a conventionally used polymer resin. Therefore, a resist pattern made of ceramics such as silicon carbide has higher dry etching resistance than a resist pattern made of polymer resin. Therefore, according to the present resist material, a photoresist material having high dry etching resistance can be provided.

Moreover, since the photoresist material according to the present embodiment is crosslinked or converted by baking when irradiated with extreme ultraviolet rays, a strong network can be constructed. As used herein, "calcination conversion" refers to converting an organic substance into an inorganic substance by calcination. Therefore, the photoresist material according to this embodiment can prevent evaporation of the photoresist material even when exposed using high-intensity extreme ultraviolet rays such as pulsed extreme ultraviolet rays. Note that pulsed extreme ultraviolet light refers to extreme ultraviolet light whose waveform has an extremely narrow half-width when viewed along the time axis. In this specification, pulsed extreme ultraviolet rays refer to extreme ultraviolet rays whose half-width is 1 nanosecond or less. Such pulsed extreme ultraviolet rays have a very high intensity per pulse. The intensity per pulse of the pulsed extreme ultraviolet rays is not limited, but is, for example, 10 ⁹ W/cm ² or more and 10 ¹⁴ W/cm ² or less. The photoresist material according to this embodiment can prevent evaporation of the photoresist material even when exposed using such high-intensity pulsed extreme ultraviolet rays. Therefore, when exposing using high-intensity pulsed extreme ultraviolet rays, the photoresist material according to this embodiment can shorten the exposure time.

(polymer alloy)
The polymer alloy contains at least one of polycarbosilane, polysiloxane, polysilazane, and polyorganoborosilazane. As used herein, "polymer alloy" means a polymer multicomponent system, and includes a mixture of a polymer and a monomer having a double bond.

Polycarbosilane is a polymer whose main chain is a skeleton in which silicon atoms and carbon atoms are alternately bonded. The main chain may be linear, branched or cyclic, and may have a three-dimensional crosslinked structure. The substituent on the polycarbosilane may have any structure as long as it does not impair the effects of the present invention. Examples of the substituent include, in addition to hydrogen, a methyl group, a benzene ring, a benzene derivative, or a carbon chain having two or more carbon atoms that may contain a hetero atom. Note that the heteroatom is preferably selected from boron (B), nitrogen (N), oxygen (O), phosphorus (P), and sulfur (S). Further, the polycarbosilane preferably has a molecular weight of 200 or more and 40,000 or less. When the molecular weight is less than 200, evaporation in vacuum tends to occur, and when it is more than 40,000, the volume of the polymer chain becomes large, making it difficult to obtain a fine pattern. From the viewpoint of acting as a crosslinking agent, allylhydridopolycarbosilane is preferred among carbosilanes.

Polysiloxane is a polymer whose main chain is a skeleton in which silicon atoms and oxygen atoms are alternately bonded. The main chain may be linear, branched or cyclic, and may have a three-dimensional crosslinked structure. The substituent on the polysiloxane may have any structure as long as it does not impair the effects of the present invention. Examples of the substituent include, in addition to hydrogen, a methyl group, a benzene ring, a benzene derivative, or a carbon chain having two or more carbon atoms that may contain a hetero atom. Further, the polysiloxane preferably has a molecular weight of 200 or more and 40,000 or less. When the molecular weight is less than 200, evaporation in vacuum tends to occur, and when it is more than 40,000, the volume of the polymer chain becomes large, making it difficult to obtain a fine pattern.

Polysilazane is a polymer whose main chain is a skeleton in which silicon atoms and nitrogen atoms are alternately bonded. The main chain may be linear, branched or cyclic, and may have a three-dimensional crosslinked structure. The substituent on polysilazane may have any structure as long as it does not impair the effects of the present invention. Examples of the substituent include, in addition to hydrogen, a methyl group, a benzene ring, a benzene derivative, or a carbon chain having two or more carbon atoms that may contain a hetero atom. Further, the polysilazane preferably has a molecular weight of 200 or more and 40,000 or less. When the molecular weight is less than 200, evaporation in vacuum tends to occur, and when it is more than 40,000, the volume of the polymer chain becomes large, making it difficult to obtain a fine pattern.

Polyorganobolosilazane is a polymer whose main chain is a skeleton consisting of a combination of silicon-nitrogen-silicon, silicon-nitrogen-boron, and boron-nitrogen-boron. The main chain may be linear, branched or cyclic, and may have a three-dimensional crosslinked structure. The substituent on the polyorganoborosilazane may have any structure as long as it does not impair the effects of the present invention. Examples of the substituent include, in addition to hydrogen, a methyl group, a benzene ring, a benzene derivative, and a carbon chain having two or more carbon atoms that may contain a hetero atom. Further, the polyorganobolosilazane preferably has a molecular weight of 200 or more and 40,000 or less. When the molecular weight is less than 200, evaporation in vacuum tends to occur, and when it is more than 40,000, the volume of the polymer chain becomes large, making it difficult to obtain a fine pattern.

The polymer alloy may contain other polymers and monomers in addition to at least one of polycarbosilane, polysiloxane, polysilazane, and polyorganoborosilazane. Examples include polymers containing antioxidants and light stabilizers, resist materials, and nanoparticles (metal oxide precursors) that are coordination-stabilized with high-boiling monomers and vinyl monomers described below.

In this embodiment, polycarbosilane and allylhydridopolycarbosilane are employed as the polymers constituting the polymer alloy. The structure of polycarbosilane is shown in the following general formula (I), and the structure of allylhydridopolycarbosilane is shown in the following general formula (II). In this embodiment, 1 wt % allylhydridopolycarbosilane is added to polycarbosilane and dissolved in cyclohexane. A polymer alloy is produced by stirring a cyclohexane solution containing polycarbosilane and allylhydridopolycarbosilane for 10 minutes, and then removing the cyclohexane.

In this embodiment, a photoresist solution is prepared by dissolving the obtained polymer alloy in toluene at a concentration of 5 wt%. The photoresist solution configured in this manner can be used in photolithography, including spin coating, exposure, and development on a substrate.

When the polymer alloy contains polycarbosilane and allylhydridopolycarbosilane, the ratio of allylhydridopolycarbosilane to polycarbosilane is preferably 0.1 wt% or more and 50 wt% or less, and 1 wt% or more and 10 wt%. % or less is more preferable. By having such a range, a resist pattern is obtained in which the photoreaction progresses in the exposed area and does not progress in the area shielded by the photomask, and which can be exposed with a realistic exposure time. be able to. As used herein, the term "photoreaction" refers to the formation of crosslinks in the resist material by exposure to light or conversion by firing.

The polymer alloy can be obtained using a known production method. For example, it can be obtained by dissolving it in an organic solvent, stirring it, and then removing the organic solvent. The organic solvent is preferably a solvent that dissolves the polymer contained in the polymer alloy, and can be appropriately selected by those skilled in the art depending on the polymer used.

When the photoresist material according to one embodiment of the present invention includes a polymer alloy, the film thickness of the photoresist material coated on the substrate is determined from the viewpoint of forming a high-definition resist pattern and suppressing peeling of the resist pattern. The thickness is preferably 10 nm or more and 250 nm or less. When the wavelength is 250 nm or more, effects such as crosslinking due to exposure do not reach the substrate, and peeling and chipping are likely to occur during development.

[Embodiment 2]
<Photoresist material>
A photoresist material according to Embodiment 2 of the present invention is a photoresist material for extreme ultraviolet lithography, and includes a metal oxide precursor. In the photoresist material according to this embodiment, the metal oxide is converted into a ceramic by crosslinking or firing conversion by irradiation with extreme ultraviolet rays. Therefore, by exposing the photoresist material according to this embodiment to extreme ultraviolet rays, a resist pattern made of metal oxide ceramics can be obtained.

A resist pattern made of metal oxide ceramics has higher hardness than a resist pattern made of a conventionally used polymer resin. Furthermore, because the film density increases through crosslinking or firing conversion, and at the same time it becomes inorganic ceramic, a resist pattern made of metal oxide ceramics has higher dry etching resistance than a resist pattern made of polymer resin. Therefore, according to the present resist material, a photoresist material having high dry etching resistance can be provided.

Further, like the photoresist material according to Embodiment 1, the photoresist material according to this embodiment is crosslinked or converted by baking when irradiated with extreme ultraviolet rays, so that a strong network can be constructed. Therefore, the photoresist material according to this embodiment can prevent evaporation of the photoresist material even when exposed using high-intensity extreme ultraviolet rays such as pulsed extreme ultraviolet rays. Therefore, when exposing using high-intensity pulsed extreme ultraviolet rays, the photoresist material according to this embodiment can shorten the exposure time.
(metal oxide precursor)
In the photoresist material according to one embodiment of the present invention, the metal oxide precursor preferably contains any one of titanium, zirconium, and hafnium. According to the above configuration, a resist pattern of ceramics made of metal oxide can be obtained by exposure using extreme ultraviolet rays. Therefore, the present photoresist material can provide a photoresist material with high dry etching resistance. In addition, when producing a resist pattern by irradiating electron beams or EUV light, the metal oxide precursor should contain hafnium because the larger the radiation absorption cross section, the higher the sensitivity to the electron beam or EUV light. is more preferable. An example of the metal oxide precursor is shown in the following general formula (III). Note that in formula (III), MO _x means a metal oxide.

The metal oxide precursor can be obtained by a known production method. For example, it can be obtained by stirring and reacting a metal alkoxide and methyl methacrylate in a suitable organic solvent.

When produced by the above method, examples of the metal alkoxide include titanium (IV) tetraisoprooxide, zirconium (IV) tetraisoprooxide, and hafnium (IV) tetraisoprooxide.

When the photoresist material according to one embodiment of the present invention includes a metal oxide precursor, the film thickness of the photoresist material is 5 nm or more and 120 nm or more from the viewpoint of forming a high-definition resist pattern and suppressing collapse of the resist pattern. It is preferable that it is below.

A resist pattern produced using a photoresist material containing a metal oxide precursor according to one embodiment of the present invention can be used as a dielectric film for a high refractive lens or a waveguide of a millimeter wave device.

(optional ingredient)
The photoresist material according to one embodiment of the present invention may contain other components as necessary in addition to the polymer alloy or the metal oxide precursor. Examples of other components include antioxidants, photoacid generators, surfactants, amines, dissolution inhibiting compounds, dyes, plasticizers, photosensitizers, and light absorbers.

The photoresist material according to one embodiment of the present invention can be manufactured by dissolving a polymer alloy or a metal oxide precursor and, if necessary, other components in an organic solvent component. Any organic solvent may be used as long as it can dissolve each component to be used and form a uniform solution, and any organic solvent may be selected as appropriate from those conventionally known as solvents for photoresist materials. be able to. Examples include toluene, 1-propanol, alkylene glycol monoalkyl ether carboxylates such as propylene glycol monomethyl ether acetate (PGMEA), and the like.

[Embodiment 3]
<Resist pattern manufacturing method>
With reference to FIG. 1, a resist pattern manufacturing method M10 (hereinafter also simply referred to as "manufacturing method M10") according to the third embodiment will be described. FIG. 1 is a flowchart of a resist pattern manufacturing method M10 according to Embodiment 1 of the present invention.

As shown in FIG. 1, the manufacturing method M10 includes a coating step S11, an exposure step S12, and a developing step S13. According to the manufacturing method M10, since the photoresist material is crosslinked or converted by firing by exposing it to light, a resist pattern made of ceramics can be obtained as a result. According to the present resist material, a photoresist material having high dry etching resistance can be provided.

The coating step S11 is a step of coating the substrate with a polymer alloy containing at least one of polycarbosilane, polysiloxane, polysilazane, and polyorganobolosilazane, or a resist material containing a metal oxide precursor. The resist material used in this embodiment is the photoresist described in either Embodiment 1 or Embodiment 2. Therefore, in this embodiment, description regarding the photoresist will be omitted.

The resist material can be applied onto the substrate by a known method. For example, it can be applied by spin coating, spraying, drop casting, or the like. Of the pair of main surfaces of the substrate, at least the main surface to which the resist material is applied is preferably flat. However, the smoothness of the main surface of the substrate is not particularly limited. Furthermore, the material constituting the substrate is not limited. Examples of materials constituting the substrate include insulators such as quartz and sapphire, semiconductors such as silicon and gallium arsenide, and metals such as aluminum and copper.

The exposure step S12 is a step in which the resist material is exposed using extreme ultraviolet rays or electron beams. In the case of exposure using extreme ultraviolet light including pulsed extreme ultraviolet light, a desired pattern is transferred to the resist material by stacking a photomask in close proximity to the resist material applied in the coating step S11. The photomask is not particularly limited as long as it has a desired pattern formed by regions that transmit extreme ultraviolet rays and regions that block extreme ultraviolet rays. On the other hand, when exposing using an electron beam, a desired pattern is drawn on the resist material by scanning the electron beam. In the following, extremely short ultraviolet rays and electron beams are collectively referred to as radiation unless they need to be particularly distinguished.

The radiation used in the exposure step S12 may be any radiation that causes a chemical reaction in the resist material, and examples thereof include electron beams, ultraviolet rays, extreme ultraviolet rays, and the like. An example of a chemical reaction is a photoreaction. However, the form of the chemical reaction is not limited to this. Examples of extreme ultraviolet rays include continuous wave extreme ultraviolet rays whose intensity does not change over time and pulsed extreme ultraviolet rays. The light used in the exposure step S12 is preferably extreme ultraviolet light, and among extreme ultraviolet light, pulsed extreme ultraviolet light is more preferable. By using extreme ultraviolet rays, a pattern with higher definition can be obtained in a shorter exposure time than when using ultraviolet rays. The radiation used in the exposure step S12 can be irradiated with a normal irradiation device used in the technical field.

The exposure amount or irradiation amount in the exposure step S12 may be an exposure amount or irradiation amount that causes at least a chemical reaction of crosslinking in the resist material. When exposing using pulsed extreme ultraviolet rays, the intensity of the pulsed extreme ultraviolet rays is preferably 10 ⁹ W/cm ² or more and 10 ¹⁴ W/cm ^{2 or} less. The exposure amount or irradiation amount in the exposure step S12 may be adjusted as appropriate by the exposure time, the number of pulses, or attenuation by the metal filter.

Note that the exposure amount or irradiation amount may be an exposure amount or irradiation amount that causes firing conversion in addition to crosslinking in the resist material. According to this configuration, a fired resist pattern can be obtained by simply performing the exposure step S12. Therefore, a resist pattern having higher dry etching resistance than a resist pattern made of a crosslinked resist material can be obtained.

The developing step S13 is a step of developing the resist pattern by immersing the exposed resist material in a developer. The developer used for development can be appropriately determined depending on the resist material. For example, when the resist material includes a polymer alloy containing at least one of polycarbosilane, polysiloxane, polysilazane, and polyorganoborosilazane, toluene is suitable as the developer. Further, for example, when the resist material contains a metal oxide precursor, cyclohexanone is suitable as the developer.

(Modified example)
The exposure step S12 may include a first exposure step of exposing the resist material using extreme ultraviolet rays, and a second exposure step.

In this modification, the amount of exposure of extreme ultraviolet rays irradiated to the resist material in the second exposure step is determined to exceed the amount of exposure of extreme ultraviolet rays irradiated to the resist material in the first exposure step. The amount of exposure to extreme ultraviolet rays in the first exposure step is preferably such that a crosslinking photoreaction proceeds in the resist material. Further, it is preferable that the exposure amount of extreme ultraviolet rays in the second exposure step is an exposure amount that converts the resist material into baking.

By setting the exposure amount in each of the first exposure step and the second exposure step in this way, the resist material can be crosslinked in the first exposure step, and the resist material can be baked and converted in the second exposure step. I can do it. Therefore, a resist pattern made of ceramic can be obtained by firing and converting the resist material using only the exposure step S12 using extreme ultraviolet rays. In other words, a resist pattern made of ceramic can be obtained without performing a firing process using a furnace. Therefore, a resist pattern with improved dry etching resistance can be obtained in a short time.

Note that among the first exposure process and the second exposure process, the second exposure process uses high-intensity extreme ultraviolet rays. Therefore, it is preferable to use pulsed extreme ultraviolet rays in the second exposure step. Note that when pulsed extreme ultraviolet rays are used in the second exposure step, it is preferable to use pulsed extreme ultraviolet rays also in the first exposure step.

[Embodiment 4]
<Resist pattern manufacturing method>
With reference to FIG. 2, a resist pattern manufacturing method M20 (hereinafter also simply referred to as "manufacturing method M20") according to the fourth embodiment will be described. FIG. 1 is a flowchart of a resist pattern manufacturing method M20 according to Embodiment 1 of the present invention.

As shown in FIG. 2, the manufacturing method M20 includes a coating step S21, an exposure step S22, a developing step S23, and a baking step S24. Each of the coating process S21, the exposure process S22, and the developing process S23 is the same as each of the coating process S11, the exposure process S12, and the developing process S13 in the manufacturing method M10. Therefore, in this embodiment, descriptions of the coating process S21, the exposure process S22, and the developing process S23 are omitted. Note that the exposure amount or irradiation amount in the exposure step S22 is determined so that the crosslinking photoreaction proceeds in the resist material.

The baking step S24 is a step carried out after the developing step S23, and is a step of converting the developed resist material into baking to obtain a layered member made of an insulator or semiconductor to which the pattern of the photomask has been transferred. be. In the baking step S24, an electric furnace is used to bake the developed resist material.

In the manufacturing method M20, the firing step S24 is performed after the exposure step S22, so the resist material can be reliably turned into ceramic. Therefore, it is possible to reduce the non-ceramic components that may be contained in the obtained resist pattern, so that the dry etching resistance of the resist pattern can be further improved. Further, when using a resist material containing a metal oxide precursor, the film density of the pattern can be improved without changing the state of the metal oxide due to baking, so that etching resistance can be improved. Furthermore, since excess organic matter can be removed by firing, the generation of outgas can be significantly suppressed.

Baking conversion can be performed by heating the developed resist material. Heating is not particularly limited, but from the viewpoint of preventing oxidation, it is preferable to perform the heating in a vacuum or under an argon atmosphere. From the viewpoint of thermal decomposition and calcination conversion temperature, the heating temperature is preferably 400°C or higher, more preferably 600°C or higher, and particularly preferably 800°C or higher. Further, from the viewpoint of protecting the substrates, it is preferable that the melting point of each substrate is 100° C. or lower. The density of ceramics can be adjusted as appropriate by adjusting the heating time. When heating at 400°C or higher, heating is preferably at least 10 hours; when heating at 600°C or higher, heating is preferably at least 5 hours; when heating at 800°C or higher, heating is preferably at least 2 hours. .

The method for manufacturing a resist pattern according to one aspect of the present invention may include steps other than the steps shown in

Embodiments

1 and 2. Other processes include, for example, a wet etching process, a dry etching process, and the like. Other steps can be performed using known methods.

[Embodiment 5]
[Resist pattern]
With reference to FIG. 3, resist pattern 1 according to the fifth embodiment will be described. FIG. 3 is a perspective view of the resist pattern 1.

The resist pattern 1 is an amorphous film made of silicon carbide and is two-dimensionally patterned. However, the resist pattern 1 may be an amorphous film made of at least one of silicon carbide, silicon dioxide, silicon nitride, and borosilicon carbonitride. According to such a configuration, the ceramic insulating film can be formed using lithography technology.

The resist pattern 1 includes a substrate 10 and a resist 11. In the resist pattern 1 shown in FIG. 3, the resist 11 is directly formed on one main surface (the upper main surface in FIG. 3) of the substrate 10. However, one or more other layers (for example, a metal layer, a semiconductor layer, etc.) may be provided between the substrate 10 and the resist 11. Further, one or more other layers (for example, a metal layer, a semiconductor layer, etc.) may be provided above the resist 11 and so as to cover the resist 11. Resist 11 is made of silicon carbide. The resist 11 can be produced by using a polymer alloy containing at least polycarbosilane among the polymer alloys described in [Photoresist Material]. However, the resist 11 may be made of at least one of silicon carbide, silicon dioxide, silicon nitride, and borosilicon carbonitride. In this case, the resist 11 can be produced by using at least one of polycarbosilane, polysiloxane, polysilazane, and polyorganoborosilazane among the polymer alloys described in [Photoresist material]. . The substrate 10 is the same as the substrate used in the manufacturing method M10 shown in FIG. Therefore, in this embodiment, description of the substrate 10 is omitted.

The resist pattern 1 can be manufactured by using the resist material described in Embodiment 1 and implementing the manufacturing method M10 shown in FIG. 1 or the manufacturing method M20 shown in FIG. 2. Therefore, in this embodiment, description of the resist 11 is omitted.

[Additional notes]
The present invention is not limited to the embodiments described above, and various modifications can be made within the scope of the claims, and embodiments obtained by appropriately combining technical means disclosed in different embodiments. are also included within the technical scope of the present invention.

[Preparation of sample for irradiation]
(Example 1)
Allylhydridopolycarbosilane (SMP-10, Starfire Systems, USA) was added to polycarbosilane (NIPSI (registered trademark) - Type A, manufactured by Nippon Carbon Co., Ltd.), and the ratio of allylhydridopolycarbosilane to polycarbosilane was After adding it to a concentration of 1 wt %, dissolving it in cyclohexane and stirring for 10 minutes, the cyclohexane was removed to produce a polycarbosilane polymer alloy. The obtained polymer alloy was dissolved in toluene to make a 5 wt % solution, and then spin coated onto a silicon wafer to obtain a sample for irradiation with a film thickness of about 200 nm.

(Example 2)
A sample for irradiation with a film thickness of about 200 nm was obtained by performing the same operation as in Example 1, except that the amount of allylhydridopolycarbosilane added was changed to 5 wt%.

(Example 3)
A metal alkoxide (titanium (IV) tetraisoprooxide) was reacted with methyl methacrylate in a 1-propanol solution with stirring at room temperature for 1 hour to prepare a metal oxide precursor. Next, a sample for irradiation with a film thickness of about 80 nm was prepared by spin coating on a silicon wafer.

(Example 4)
A sample for irradiation with a film thickness of about 80 nm was prepared in the same manner as in Example 3 except that zirconium (IV) tetraisoprooxide was used as the metal alkoxide.

(Example 5)
A sample for irradiation with a film thickness of about 80 nm was prepared in the same manner as in Example 3 except that hafnium (IV) tetraisoprooxide was used as the metal alkoxide.

(Comparative example 1)
Polymethyl methacrylate (PMMA, Mw ~350,000, manufactured by Aldrich) was dissolved in toluene to make a 0.7 wt% solution, and then spin coated onto a silicon wafer to form a sample for irradiation with a film thickness of approximately 200 nm. Obtained.

(Comparative example 2)
A sample for irradiation with a film thickness of about 200 nm was obtained in the same manner as in Comparative Example 1 except that ZEP520A (manufactured by Nippon Zeon Co., Ltd.) was used as the resist polymer.

(Comparative example 3)
A sample for irradiation with a film thickness of about 200 nm was obtained in the same manner as in Comparative Example 1 except that UVIII (manufactured by ROHM and HRRS) was used as the resist polymer.

(Comparative example 4)
A sample for irradiation with a film thickness of about 200 nm was obtained in the same manner as in Comparative Example 1 except that PHS (polyhydroxystyrene, Mw ~15,000, manufactured by Aldrich) was used as the resist polymer.

Note that in Examples 1 to 5 and Comparative Examples 1 to 3, reagents whose manufacturers are not listed were those commonly used in the technical field.

〔irradiation〕
Examples 1 to 5 and Comparative Examples 1 to 3 were irradiated using the method shown below.

(electron beam irradiation)
Using an electron beam (EB) irradiation device (EB-ENGINE (manufactured by Hamamatsu Photonics), 50 kV), a stainless steel shield plate was brought into contact with the sample side to serve as a mask. Scan irradiation was applied to a ¹ cm square area of each sample so that the absorbed dose was 100 μC/cm ² to 600 μC/cm ² .

(Extreme ultraviolet (EUV) irradiation)
Using an EUV exposure device (ENERGETIQ, EQ-10, Electrodeless Z-Pinch ^™ , 10Watt), insert a 1 cm ^square mask on the light source side so that the exposure dose is 1 mJ/cm ² to 250 mJ/cm ² The sample was spot irradiated.

(Pulsed EUV irradiation)
Pulsed EUV (1 to 17 nJ/pulse) with a spot size of about 7 μm was irradiated using a pulsed EUV irradiation device manufactured by the Kansai Photon Science Institute of the Quantum Science and Technology Research and Development Organization (QST). In addition, pulsed EUV (1 to 17 nJ/pulse) with a spot size of approximately 7 μm was irradiated at the X-ray free electron laser facility SACLA of the Synchrotron Radiation Research Center.

〔developing〕
The sample after irradiation was processed using a developer (toluene: Examples 1 to 2, cyclohexanone: Examples 3 to 6, mixed solution (methyl isobutyl ketone (MIBK): isopropyl alcohol (IPA) = 1:3): Comparative example 1, anisole Alternatively, ZMD-B: Comparative Example 2, alkaline developer NMD-3: Comparative Example 3) was immersed for 1 minute, and then the solvent on the surface was removed with a blower and development was performed.

[Evaluation of sensitivity]
For the samples of Examples 1 to 5 that were subjected to EB irradiation or EUV irradiation, the film thickness of the remaining pattern was measured and a sensitivity curve was created. The results of Examples 1 and 2 in which EB irradiation or EUV irradiation was performed are shown in FIG. In FIG. 4, (a) is the sensitivity curve of Example 1 subjected to EB irradiation, (b) is the sensitivity curve of Example 2 subjected to EB irradiation, (c) is the sensitivity curve of Example 1 subjected to EUV irradiation, ( d) shows the sensitivity curve of Example 2 subjected to EUV irradiation. Further, the results of Examples 3 to 5 in which EB or EUV irradiation was performed are shown in FIG. In FIG. 5, (a) is the sensitivity curve of Example 3 subjected to EB irradiation, (b) is the sensitivity curve of Example 4 subjected to EB irradiation, (c) is the sensitivity curve of Example 5 subjected to EB irradiation, ( d) shows the sensitivity curve of Example 3 with EUV irradiation, (e) shows the sensitivity curve of Example 4 with EUV irradiation, and (f) shows the sensitivity curve of Example 5 with EUV irradiation. Further, in FIGS. 4 and 5, the vertical axis indicates the standardized film thickness (nm), and the horizontal axis indicates the irradiation amount or exposure amount (μC/cm ² or mJ/cm ² ).

As shown in FIG. 4, in a comparison between Examples 1 and 2, it was found that sensitivity was improved for both EB irradiation and EUV irradiation by changing the amount of allylhydridopolycarbosilane added, which acts as a crosslinking agent.

As shown in FIG. 5, in the comparison of Examples 3 to 5, it was found that the sensitivity of EB improves as the heavy atoms have a larger radiation absorption cross section. Furthermore, with respect to EUV irradiation, all of Examples 3 to 5 exhibited extremely high sensitivity, reflecting the high absorption cross section of EUV.

[Firing conversion]
The EB irradiated sample after development was placed in an argon atmosphere and heated at 800° C. for 2 hours to convert it to firing.

[Resist pattern residual evaluation]
The remaining resist patterns of Examples 2 and 3 after firing conversion were evaluated. FIG. 6 shows the appearance of the resist films of Examples 2 and 3 and Comparative Example 1 before and after the baking conversion. In FIG. 6, (a) shows the state of the resist film of Example 2 before and after the baking conversion, (b) shows the state of the resist film of Example 3 before and after the baking conversion, and (c) shows the state of the resist film of Example 3 before and after the baking conversion. The state of the resist film of Comparative Example 1 before and after conversion is shown. In FIG. 6, if the shape (square) of the resist film before firing conversion remains after firing conversion, it can be determined that the resist pattern remains.

As shown in FIG. 6, Examples 2 and 3 exhibited high heat resistance, and it was confirmed that the pattern remained even after the firing conversion. On the other hand, in Comparative Example 1, evaporation occurred due to thermal decomposition, and no resist pattern remained. In Comparative Examples 2 and 3 as well, evaporation due to thermal decomposition occurred and no resist pattern remained.

[Evaluation of etching resistance]
The developed Examples 2 to 5 and Comparative Examples 1 to 4, as well as the baked-converted Examples 2 to 5, were dry-etched and the etching resistance was evaluated. The etching conditions were dry etching using Ar/CF ₄ gas, and evaluation was made from the slope of the amount of decrease in film thickness with respect to time (seconds). Note that in Examples 2 to 5 in which etching resistance was evaluated, samples that were irradiated with an electron beam were used. Furthermore, in Comparative Examples 1 to 4, the coated samples were used as they were.

The etching resistance of Example 2 and Comparative Example 1 is shown in FIG. 7, and the etching resistance of Example 3 and Comparative Examples 1 to 4 is shown in FIG. 8(a). is shown in FIG. 8(b), and the etching resistance of Example 5 and Comparative Examples 1 to 4 is shown in FIG. 8(c). In FIGS. 7 and 8, the vertical axis shows the film thickness (nm) after etching, and the horizontal axis shows the etching time (seconds). In addition, approximate curves are shown in which the intercept of each etching time with respect to the film thickness is set to 0 for developed Examples 3 to 5, baked-converted Examples 3 to 5, and Comparative Example 1.

As shown in FIG. 7, when the etching resistance of Example 2 was compared with Comparative Example 1, it was found that the etching resistance was significantly improved. In addition, it was found that Example 2, which underwent firing conversion, had further improved etching resistance.

As shown in FIG. 8, all of Examples 3 to 5 exhibited extremely high etching resistance compared to Comparative Examples 1 to 4. Since the state of the metal oxide does not change due to firing, there is little improvement in etching resistance in Examples 3 to 5 before and after firing, but firing can remove excess organic matter and has the effect of greatly suppressing the generation of outgas. . Furthermore, the film density of the pattern is improved by baking, which has the effect of increasing etching resistance.

[Evaluation of resist pattern formation by pulsed EUV irradiation]
The photoresist material of the present invention has sufficient pattern forming ability even with a pulsed EUV light source. Resist patterns produced using Examples 2 and 5 by irradiation with EUV (wavelength: 13.5 nm) light derived from a free electron laser are shown in FIGS. 9 and 10, respectively.

As shown in Figure 9, it is estimated that the energy required for firing conversion in addition to crosslinking is provided from the energy per shot. Therefore, the usefulness of inorganic resist materials for pulsed EUV that undergoes crosslinking-baking conversion and the exposure It turned out that the process was proven.

〔summary〕
The photoresist material according to aspect 1 of the present invention is a photoresist material for extreme ultraviolet lithography, and is a polymer alloy containing at least one of polycarbosilane, polysiloxane, polysilazane, and polyorganoborosilazane, or , including metal alkoxides.

The photoresist material configured as described above is crosslinked or converted by firing by being irradiated with extreme ultraviolet rays, and as a result, a resist pattern made of ceramics can be obtained. According to the present resist material, a photoresist material having high dry etching resistance can be provided.

In the photoresist material according to aspect 2 of the present invention, in addition to the configuration of the photoresist material according to aspect 1, a configuration including a polymer alloy containing polycarbosilane and allylhydridopolycarbosilane is adopted. .

An example of a polymer alloy containing at least one of polycarbosilane, polysiloxane, polysilazane, and polyorganoborosilazane includes a polymer alloy containing polycarbosilane and allylhydridopolycarbosilane. According to the above configuration, a ceramic resist pattern made of silicon carbide can be obtained by exposure using extreme ultraviolet rays. Therefore, the present photoresist material can provide a photoresist material with high dry etching resistance.

In the photoresist material according to aspect 3 of the present invention, in addition to the structure of the photoresist material according to aspect 2, the ratio of allylhydridopolycarbosilane to polycarbosilane is 0.1 wt% or more and 50 wt% or less. configuration has been adopted.

According to the above configuration, it is possible to obtain a resist pattern in which the photoreaction progresses in the exposed area and the photoreaction does not proceed in the area shielded by the photomask, and which can be exposed with a realistic exposure time. can.

In the photoresist material according to aspect 4 of the present invention, in addition to the configuration of the photoresist material according to aspect 1, a configuration is adopted in which the metal alkoxide contains any one of titanium, zirconium, and hafnium. .

As described above, the metal alkoxide preferably contains any one of titanium, zirconium, and hafnium. According to the above configuration, a resist pattern of ceramics made of metal oxide can be obtained by exposure using extreme ultraviolet rays. Therefore, the present photoresist material can provide a photoresist material with high dry etching resistance.

A method for manufacturing a resist pattern according to aspect 5 of the present invention is to apply a resist material containing a polymer alloy containing at least one of polycarbosilane, polysiloxane, polysilazane, and polyorganobolosilazane or a metal alkoxide onto a substrate. an exposure step of bringing a photomask close to a substrate coated with the resist material to expose the resist material, and a developing step of developing the exposed resist material.

The resist material configured as described above is crosslinked or fired by being exposed to light, and becomes a two-dimensional pattern of ceramics. In other words, according to this manufacturing method, a resist pattern made of ceramics can be obtained. Therefore, a photoresist pattern having high dry etching resistance can be provided.

In the resist pattern manufacturing method according to aspect 6 of the present invention, in addition to the means of the resist pattern manufacturing method according to aspect 5, there is provided a baking step performed after the developing step, in which the developed resist material is A configuration is adopted which further includes a firing step of obtaining a layered member made of an insulator or semiconductor onto which the pattern of the photomask is transferred by performing firing conversion.

According to the above method, since the firing process is performed after the exposure process, the resist pattern can be reliably made into ceramic. Therefore, the dry etching resistance of the obtained resist pattern can be further improved.

In the resist pattern manufacturing method according to Aspect 7 of the present invention, in addition to the means of the resist pattern manufacturing method according to Aspect 5, the light used in the exposure step is extreme ultraviolet rays.

According to the above method, the present manufacturing method produces the same effects as the photoresist material according to Aspect 1 described above. Further, according to the present manufacturing method, a pattern with higher definition can be obtained in a shorter exposure time than when exposing using ultraviolet rays.

In the resist pattern manufacturing method according to aspect 8 of the present invention, in addition to the means of the resist pattern manufacturing method according to aspect 7, the exposure step includes a first exposure step of exposing the resist material using extreme ultraviolet rays. and a second exposure step, and the amount of exposure of the extreme ultraviolet rays irradiated to the resist material in the second exposure step is equal to the amount of exposure of the extreme ultraviolet rays irradiated to the resist material in the first exposure step. exceed.

According to the above method, it is possible to perform baking conversion of the photoresist material without performing a baking process separate from the exposure process. Therefore, a resist pattern with improved dry etching resistance can be obtained in a short time.

The resist pattern according to aspect 9 of the present invention is an amorphous film made of at least one of silicon carbide, silicon dioxide, silicon nitride, and borosilicon carbonitride, and is a two-dimensionally patterned amorphous film. Consisting of

According to the above configuration, the ceramic insulating film can be formed using lithography technology.

1 Resist pattern 10 Substrate 11 Resist M10 Resist pattern manufacturing method M20 Resist pattern manufacturing method S11 Coating process S12 Exposure process S13 Developing process S21 Coating process S22 Exposure process S23 Developing process S24 Baking process

Claims

A photoresist material for extreme ultraviolet lithography, comprising a polymer alloy containing at least one of polycarbosilane, polysiloxane, polysilazane, and polyorganobolosilazane, or a metal oxide precursor.
A photoresist material characterized by:
including polycarbosilane and a polymer alloy containing allylhydridopolycarbosilane,
2. The photoresist material of claim 1.
The ratio of allylhydridopolycarbosilane to polycarbosilane is 0.1 wt% or more and 50 wt% or less,
3. The photoresist material of claim 2.
The metal oxide precursor contains any one of titanium, zirconium, and hafnium,
2. The photoresist material of claim 1.
a coating step of applying a resist material containing a polymer alloy containing at least one of polycarbosilane, polysiloxane, polysilazane, and polyorganobolosilazane, or a metal oxide precursor onto the substrate;
an exposure step of bringing a photomask close to the substrate coated with the resist material and exposing the resist material;
a developing step of developing the exposed resist material;
A method for manufacturing a resist pattern, characterized in that:
A firing step carried out after the developing step, in which a layered member made of an insulator or a semiconductor to which the pattern of the photomask is transferred is obtained by converting the developed resist material into a firing step. include,
6. The method for manufacturing a resist pattern according to claim 5.
The light used in the exposure step is extreme ultraviolet rays,
6. The method for manufacturing a resist pattern according to claim 5.
The exposure step includes a first exposure step and a second exposure step of exposing the resist material using extreme ultraviolet rays,
The amount of exposure of the extreme ultraviolet rays irradiated to the resist material in the second exposure step exceeds the amount of exposure of the extreme ultraviolet rays irradiated to the resist material in the first exposure step.
8. The method of manufacturing a resist pattern according to claim 7.
An amorphous film made of at least one of silicon carbide, silicon dioxide, silicon nitride, and borosilicon carbonitride, the amorphous film being two-dimensionally patterned.
A resist pattern characterized by: