JP2024055016A - Method for manufacturing a patterned substrate, a patterned substrate, and a patterned substrate intermediate - Google Patents

Abstract

[Problem] To provide an excellent method for producing a patterned substrate, which can easily pattern an insulating layer to obtain a patterned substrate even when a material difficult to etch is used as the insulating layer, and a patterned substrate and its patterned substrate intermediate. [Solution] In a method for producing a patterned substrate in which an insulating layer 11 and an electrode layer 12 are laminated in this order on a substrate 10, an organic resist material layer 13 is formed, and the organic resist material layer 13 is irradiated with EUV to obtain an EUV irradiated portion 13a and an EUV non-irradiated portion 13b. Then, an insulating layer 11, an electrode layer 12, and a second organic resist material layer 14 are formed thereon in this order. The second organic resist material layer 14 is irradiated with EUV and developed to obtain a patterned layer 14a, and then the electrode layer 12 is removed. Then, the insulating layer 11 and the underlying EUV non-irradiated portion 13b of the organic resist material layer 13 are removed, and the patterned layer 14a is removed. [Selected Figure] FIG. 2

Description

The present invention relates to a method for manufacturing a patterned substrate used in various semiconductor devices, a patterned substrate obtained by the method, and a patterned substrate intermediate used to obtain the patterned substrate.

In recent years, with the paradigm shift towards an advanced information society, there is a demand to handle larger amounts of information at higher speeds with greater precision, and semiconductor device technology, such as integrated circuits that use semiconductors, is advancing remarkably every day.

The manufacturing process for the above semiconductor device is explained below using a simple schematic diagram of a MOS device as an example. First, as shown in FIG. 3(a), a silicon oxide film 2 that will become a gate insulating film is formed on a silicon substrate 1 using thermal oxidation or the like. Then, as shown in FIG. 3(b), a polysilicon film 3 that will become a gate electrode is formed on the silicon oxide film 2 using a CVD (chemical vapor deposition) method or the like.

Next, as shown in Figures 3(c) and (d), the polysilicon film 3 is covered with a photoresist film 4, and exposed and developed using a desired mask by lithography to perform max-patterning of the gate electrode. Then, as shown in Figures 4(a) and (b), the polysilicon film 3 and silicon oxide film 2 are etched by, for example, the RIE method (reactive ion etching) using the patterned photoresist film 4 as a mask.

Next, as shown in FIG. 4(c), the photoresist film 4 is removed by ashing using oxygen gas. In this way, a patterned substrate having a concave-convex pattern is obtained as shown in FIG. 4(d). Then, the formation of an interlayer insulating film, patterning, metal filling, flattening, etc. are repeated to form the desired wiring and elements, and the circuits required for the device are formed.

As in the above example, silicon oxide films are often used as gate insulating films in semiconductor devices using such patterned substrates. However, in recent years, in order to meet the demand for even higher integration and speed in semiconductor devices, metal oxides with higher dielectric constants, known as "high-κ," such as hafnium oxide, hafnium silicate nitride, and hafnium aluminate, have been considered for use as gate insulating films.

In other words, the use of these materials with high relative dielectric constants is expected to suppress gate leakage current, making it possible to further thin the gate insulating film and finer the pattern, and several semiconductor devices using such high-κ materials have been proposed (see Patent Document 1, etc.).

JP 2022-8336 A

However, the high-κ materials are difficult to etch, and therefore it is not easy to directly etch an insulating layer made of a high-κ material to form a pattern. Therefore, there is a strong demand for the development of a method for efficiently etching such an insulating layer.
Incidentally, in the above-mentioned Patent Document 1, a high-κ film is used as the first insulating layer, and a general insulating film such as silicon oxide is used as the second insulating film, and the two are combined to form a laminated structure, and then only the second insulating film is etched and patterned, thereby increasing the relative dielectric constant of the entire insulating layer. However, the inventors have not succeeded in patterning the insulating film itself made of a high-κ film.

The present invention was made in consideration of these circumstances, and aims to provide an excellent method for producing a patterned substrate, which allows a patterned substrate to be obtained by easily patterning an insulating layer, even when a difficult-to-etch material such as a high-κ material is used as the insulating layer, as well as the patterned substrate and its patterned substrate intermediate obtained thereby.

In light of these circumstances, the inventors discovered that by devising a manufacturing process that utilizes an organic resist material layer when patterning an insulating layer on a substrate, it is possible to efficiently pattern an insulating layer made of a material that is difficult to etch, and thus arrived at the present invention.

That is, the present invention has the following aspects.
[1] A method for manufacturing a patterned substrate having an insulating layer and an electrode layer stacked in this order on a substrate, the method comprising the steps of: forming an organic resist material layer; irradiating the organic resist material layer with EUV in a pattern to obtain an EUV irradiated portion and an EUV non-irradiated portion; forming an insulating layer on a substrate having the EUV pattern-irradiated organic resist material layer; forming an electrode layer on the insulating layer; forming a second organic resist material layer on the electrode layer; irradiating the second organic resist material layer with EUV in a pattern to obtain an EUV irradiated portion and an EUV non-irradiated portion, and then removing the EUV non-irradiated portion and developing the EUV irradiated portion to obtain a patterned layer; removing the electrode layer exposed from the portion where the EUV non-irradiated portion has been removed; removing the insulating layer exposed from the portion where the electrode layer has been removed and the EUV non-irradiated portion of the organic resist material layer below the insulating layer; and removing the patterning layer.
[2] The method for producing a patterned substrate according to [1], wherein the organic resist material layer and the second organic resist material layer are each a layer made of an organic hydroxyoxotin layer.
[3] The method for producing a patterned substrate according to [2], wherein the organic hydroxyoxotin layer is formed using an organic hydroxyoxotin precursor represented by the following general formula (1):

[Chemical formula 1]
RSnX ₃ ... (1)
[R represents a hydrocarbon group having 1 to 30 carbon atoms, and X represents a hydrolyzable substituent.]

[4] The method for producing a patterned substrate according to any one of [1] to [3], wherein the non-EUV irradiated portion is removed with an acid.
[5] The method for producing a patterned substrate according to [4], wherein the non-EUV irradiated portion is removed by a gas phase treatment using an acidic gas.
[6] The method for producing a patterned substrate according to any one of [1] to [5], wherein the insulating layer is formed from a material that is difficult to etch.
[7] The method for producing a patterned substrate according to [6], wherein the hard-to-etch material is a high-κ material having a relative dielectric constant κ of 9 or more.
[8] The method for producing a patterned substrate according to [7], wherein the high-κ material having a relative dielectric constant κ of 9 or more is at least one compound selected from the group consisting of hafnium oxide, hafnium silicate nitride, hafnium aluminate, zirconium oxide, tantalum oxide, aluminum zirconium oxide, aluminum oxide, lanthanum oxide, and compounds of these with silica aluminum.
[9] A patterned substrate obtained by the method for producing a patterned substrate according to any one of [1] to [8], comprising an insulating layer and an electrode layer formed in this order on a substrate having an EUV irradiated portion of an organic resist material layer.
[10] An intermediate for obtaining the patterned substrate according to [9], comprising an insulating layer formed on a substrate having an organic resist material layer in which an EUV irradiated portion and an EUV non-irradiated portion are formed.
[11] The patterned substrate intermediate according to [10], which has an electrode layer on the insulating layer.
[12] The patterned substrate intermediate according to [11], which has a patterning layer on the electrode layer.

According to the method for manufacturing a patterned substrate of the present invention, when patterning an insulating layer, the patterning is performed using the EUV non-irradiated portion of the organic resist material layer provided under the insulating layer, so that even if the insulating layer is made of a material that is difficult to etch, it can be patterned efficiently. In addition, since the EUV irradiated portion of the organic resist material layer is sandwiched between the substrate and the insulating layer, even if a substrate and an insulating layer made of a material whose interface characteristics are easily unstable are combined, the two can be laminated and integrated in a stable state via the EUV irradiated portion. Moreover, since the substrate surface is covered with the organic resist material layer, there is an advantage in that the substrate can be protected from over-etching when the insulating layer is etched away.

The patterned substrate of the present invention has the advantage of exhibiting excellent electrical properties, since an insulating layer made of a material that is difficult to etch, such as a high-κ material, is efficiently formed by the manufacturing method of the present invention. The substrate is also protected from over-etching, providing stable quality.

Furthermore, the patterned substrate intermediate of the present invention allows the patterned substrate to be manufactured efficiently.

1A to 1D are explanatory views of a manufacturing process according to one embodiment of the present invention. 1A to 1D are explanatory views of a manufacturing process according to one embodiment of the present invention. 1A to 1D are explanatory diagrams of a conventional manufacturing process for a patterned substrate. 1A to 1D are explanatory diagrams of a conventional manufacturing process for a patterned substrate.

The present invention will be described in more detail below based on the embodiments of the present invention, but the present invention is not limited to the following embodiments.
In the present invention, when expressed as "Y to Z" (Y and Z are arbitrary numbers), unless otherwise specified, it includes the meaning of "Y or more and Z or less", as well as "preferably larger than Y" or "preferably smaller than Z".
Furthermore, when it is expressed as "Y or more" (Y is any number) or "Z or less" (Z is any number), it also means that "it is preferably greater than Y" or "it is preferably less than Z".

One embodiment of the present invention relates to a method for manufacturing a patterned substrate in which an insulating layer 11 and an electrode layer 12 are laminated in this order on a substrate 10, as shown in FIG. 2(d), and this embodiment will be described in sequence using FIGS. 1(a) to (d) and FIGS. 2(a) to (d).
2(d), the insulating layer 11 is not formed directly on the substrate 10, but is formed on the substrate 10 via an EUV irradiation layer 13a derived from the organic resist material layer 13. Therefore, in the present invention, when "a layer is formed on a substrate" or "a layer is laminated on a substrate", this also includes cases where the layer is not formed directly on the substrate or is not laminated directly on the substrate.

<1: Formation of organic hydroxyoxotin layer>
In this embodiment, first, as shown in FIG. 1A, an organic hydroxyoxotin layer 13 is formed as an organic resist material layer on a substrate 10.

The substrate 10 is not particularly limited, and an appropriate material may be used depending on the application and required characteristics of the resulting pattern substrate. Examples of the substrate 10 include substrates made of Si, _SiO2 , SiN, SiON, SiC, BN, GaN, TiN, BPSG, SOG, Cr, CrO, CrON, MoSi, etc.

The surface of the substrate 10 (the surface on which the insulating layer 11 is formed) does not necessarily have to be a flat, uniform material, and a portion of the surface of the substrate 10 may be removed, for example, by etching to include a concave region. Conversely, a portion of the surface of the substrate 10 may include a convex region to which other material has been added, for example, by deposition. The thickness of the substrate 10 is also not particularly limited, and is set to an appropriate thickness depending on the application and type of the pattern substrate.

If the surface of the substrate 10 is hydrophobic, a hydrophilization treatment can be performed on the surface of the substrate 10 to improve adhesion with the EUV irradiated portion 13a of the organic hydroxyoxotin layer 13 formed thereon. Examples of the hydrophilization treatment include a method of imparting hydrophilic groups such as hydroxyl groups to the surface of the substrate 10 using oxygen, ozone, alcohol, etc.

As described below, the organic hydroxyoxotin layer 13 formed on the substrate 10 is used to assist in the patterning by etching of the insulating layer 11 formed after the organic hydroxyoxotin layer 13, and can be easily patterned by EUV irradiation.

To form the organic hydroxyoxotin layer 13, an organic hydroxyoxotin precursor represented by the general formula " _{RpSnXm "} is used.
In the above formula, "R" is a hydrocarbon group having a beta hydrogen, preferably a hydrocarbon group having 1 to 30 carbon atoms, more preferably 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably a hydrocarbon group having 2 to 6 carbon atoms. Examples of the hydrocarbon group include saturated hydrocarbon groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, t-butyl group, and 1-methylcyclopentyl group, and unsaturated hydrocarbon groups such as vinyl group and 2-propenyl group.
In the above formula, "X" means a hydrolyzable substituent, and examples thereof include halogen, amino group, alkoxy group (-OR'), alkynide (R'C≡C), azide (N ₃ --), dialkylamino group (-NR' ₂ ) (-NR'R"), alkylcarbonylamino group (-N(R')C(O)R') (-N(R')C(O)R") (-N(R")C(O)R'), carbonyloxy group (-OCOR'), carbonylamino group (-N(H)C(O)R'), and the like. R' and R" are each independently a hydrocarbon group having 1 to 10 carbon atoms. Of these, X is preferably a dialkylamino group, alkoxy group, alkylcarbonylamino group, halogen, or carbonyloxy group, and particularly preferably a dialkylamino group or an alkoxy group, and further preferably a dialkylamino group (-NR' ₂ ) or an alkoxy group (-OR').
In the above formula, “p” is an integer from 1 to 3, and “m” is an integer from 1 to 4.

The molecular weight of such organic hydroxyoxotin precursors is usually 200 to 900, preferably 240 to 700, and particularly preferably 280 to 500.

In this embodiment, among the above organic hydroxyoxotin precursors, it is particularly preferable in terms of effectiveness to use an organic hydroxyoxotin precursor represented by the following general formula (1). Like "R" in the above general formula, R in the following formula is a hydrocarbon group having a beta hydrogen, and among these, those having 1 to 15 carbon atoms, more preferably 1 to 10 carbon atoms, and even more preferably 2 to 6 carbon atoms are preferred. Also, X in the following formula is the same as "X" in the above general formula, and among these, dialkylamino groups, alkoxy groups, alkylcarbonylamino groups, halogens, and carbonyloxy groups are particularly preferred, and those in which X is a dialkylamino group or an alkoxy group are particularly preferred, and furthermore, dialkylamino groups ( _-NR'2 ) and alkoxy groups (-OR').

[Chemical formula 2]
RSnX ₃ ... (1)
[R represents a hydrocarbon group having 1 to 30 carbon atoms, and X represents a hydrolyzable substituent.]

Examples of such organic hydroxyoxotin precursors include t-butyltris(dimethylamino)tin, n-butyltris(dimethylamino)tin, t-butyltris(diethylamino)tin, di(t-butyl)di(dimethylamino)tin, sec-butyltris(dimethylamino)tin, n-pentyltris(dimethylamino)tin, isobutyltris(dimethylamino)tin, isopropyltris(dimethylamino)tin, t-butyltris(t-butoxy)tin, n-butyl(tris(t-butoxy)tin, or isopropyltris(t-butoxy)tin.

The organic hydroxyoxotin precursors may be used alone or in combination of two or more. The method for forming a layer using the organic hydroxyoxotin precursor is not particularly limited, and can be appropriately selected from various conventionally known film formation methods such as spin coating, CVD, physical vapor deposition, and atomic layer deposition.

In this embodiment, it is particularly preferable to use the CVD method. When using the CVD method, the organic hydroxyoxotin precursor and an oxygen-containing counter reactant for imparting hydroxy groups are introduced into the deposition chamber of the CVD device via separate inlets, and the two are mixed and reacted in the gas phase to form the organic hydroxyoxotin layer 13 on the substrate 10.

The oxygen-containing counter reactant is used in combination with an organic hydroxyoxotin precursor not only in the CVD method but also in other deposition methods, and serves to oxidize the organic hydroxyoxotin precursor to generate a large number of hydroxy groups. Examples of the oxygen-containing counter reactant include water, hydrogen peroxide, formic acid, alcohol, oxygen, ozone, etc., and these may be used alone or in combination of two or more kinds.

When forming the organic hydroxyoxotin layer 13 by the above-mentioned CVD method, the pressure conditions during film formation are generally 10 to 1500 Pa, and preferably 65 to 270 Pa. The temperature of the substrate 10 during film formation is generally 0 to 250°C, and preferably 20 to 150°C.

The thickness of the organic hydroxyoxotin layer 13 is not particularly limited, but it is preferable to set this thickness t1 to be very thin compared to the thickness t2 of the insulating layer 11 to be formed subsequently. That is, since the EUV irradiated portion 13a of the organic hydroxyoxotin layer 13 ultimately remains between the substrate 10 and the insulating layer 11 and becomes part of the insulating layer, if this portion is too thick, the entire pattern substrate tends to become thick. On the other hand, if this portion is too thin, the effect of making the insulating layer 11 easier to etch tends to be reduced. Therefore, the thickness t1 of the organic hydroxyoxotin layer 13 after EUV irradiation is usually 0.5 to 20 nm, preferably 5 to 15 nm. For example, if the insulating layer 11 is made of a high-κ material with a relative dielectric constant κ of 9 or more, the ratio (t1/t2) of the thickness t1 of the organic hydroxyoxotin layer 13 after EUV irradiation to the thickness t2 of the insulating layer 11 is preferably 0.04 to 0.7 (see FIG. 1[c]).

<2: Patterned irradiation of organic hydroxyoxotin layer>
Next, only specific regions of the organic hydroxyoxotin layer 13 are irradiated with EUV light to harden the layer, thereby forming hardened EUV-irradiated portions 13a and unhardened EUV-unirradiated portions 13b, as shown in FIG. 1(b).

The EUV refers to electromagnetic waves (Extreme Ultra-Violet) with a wavelength of about 10 to 15 nm. The EUV irradiation causes many of the terminal hydroxyl groups in the organic hydroxyoxotin layer 13 to crosslink with each other to form -O- bonds, hardening the EUV irradiated portion 13a. The non-EUV irradiated portion 13b does not harden.

As a light source for the EUV irradiation, a high-temperature plasma, particularly a laser-induced plasma, etc. is used. The irradiation dose depends on the thickness of the organic hydroxyoxotin layer 13, etc., but is usually preferably 15 to 80 mJ/ ^cm2 .

<3: Formation of insulating layer>
1C, an insulating layer 11 is formed on the EUV-patterned organic hydroxyoxotin layer 13. There are no particular limitations on the thickness t2 of the insulating layer 11, but as already mentioned, when the insulating layer 11 is made of a high-κ material with a relative dielectric constant κ of 9 or more, it is preferable to set the thickness t2 in relation to the thickness t1 of the EUV-irradiated portion 13a of the organic hydroxyoxotin layer 13 so that t1/t2=0.04 to 0.7.

The insulating layer 11 may be formed using silicon oxide ( _SiO2 ) or the like, which has conventionally been widely used for gate insulating layers, etc.; however, in the present invention, it is preferable to use an insulating material made of the above-mentioned difficult-to-etch material, since this has the advantage of being able to efficiently etch insulating materials made of difficult-to-etch materials, which have a high dielectric constant but are difficult to etch and therefore have limited use in semiconductor devices.

Such difficult-to-etch materials with a high dielectric constant include, for example, high-κ materials with a dielectric constant κ of 9 or more. Specific examples include hafnium oxide, hafnium silicate nitride, hafnium aluminate, zirconium oxide, tantalum oxide, aluminum zirconium oxide, aluminum oxide, lanthanum oxide, and compounds of these with silica aluminum. These may be used alone or in combination of two or more.

And in this embodiment, among the high-κ materials, hafnium oxide (κ is 13 to 18) and zirconium oxide (κ is greater than 13) are particularly suitable because they exhibit an excellent high relative dielectric constant.

The insulating layer 11 is obtained by depositing an insulating material using any of the various conventional deposition methods, such as CVD, ALD (Atomic Layer Deposition), and sputtering.

<4: Formation of electrode layer>
1(d), an electrode layer 12 is formed on the insulating layer 11. The electrode layer 12 can be obtained by depositing a semiconductive material, for example, polysilicon, by a conventionally known film deposition method such as a CVD method or a sputtering method.

The thickness of the electrode layer 12 is not particularly limited, and is set to an appropriate thickness depending on the application and required characteristics of the resulting patterned substrate.

<5: Formation of second organic hydroxyoxotin layer>
2(a), a second organic hydroxyoxotin layer 14 is formed on the electrode layer 12. The second organic hydroxyoxotin layer 14 is formed using the same organic hydroxyoxotin precursor as that used for the organic hydroxyoxotin layer 13. The second organic hydroxyoxotin layer 14 and the organic hydroxyoxotin layer 13 do not necessarily need to use the same material, and the film formation method thereof does not necessarily need to be the same, but the suitable precursor types and suitable film formation methods are common to both, and therefore description thereof will be omitted.

<6: Formation of Patterning Layer>
Next, the second organic hydroxyoxotin layer 14 is irradiated with EUV in a pattern to form a cured EUV-irradiated portion and an uncured EUV-non-irradiated portion, and the cured EUV-irradiated portion is developed by removing the EUV-non-irradiated portion to obtain a patterned layer 14a as shown in FIG. 2(b).
The patterned irradiation with EUV can be carried out in the same manner as the patterned irradiation with EUV for the organic hydroxyoxotin layer 13 .

In addition, the development of the second organic hydroxyoxotin layer 14, which removes the non-EUV irradiated parts and exposes the EUV irradiated parts, can be carried out using a wet etching process or a dry etching process (vapor phase treatment) using an acid, which is typically carried out in an etching process.

When the development is performed using the wet etching process, for example, isopropyl alcohol, n-butyl alcohol, n-butyl acetate, 2-heptanone, propylene glycol monomethyl ether acetate (PGMEA), propylene glycol monomethyl ether (PGME), butyl acetate, etc. can be used as a solvent for dissolving and removing the uncured portion of the second organic hydroxyoxotin layer 14 that has not been irradiated with EUV. These may be used alone or in combination of two or more.

Furthermore, when the development is performed using the above-mentioned dry etching process (gas phase treatment), a gentle plasma treatment (high pressure, low power) or heat treatment is performed by appropriately mixing acidic substances such as hydrogen halides, halogens, diborane, boron trichloride, other Lewis acids, and argon, or, in order to improve the selectivity with silicon, _O2 or _H2 , which are flowed in a gaseous state so as to be in sufficient contact with the EUV irradiated and non-EUV irradiated portions of the second organic hydroxyoxotin layer 14. The above-mentioned acidic substances may be used alone or in combination of two or more kinds.

In this embodiment, it is particularly preferable to use a dry etching process using plasma. When the above plasma etching process is used, the plasma process includes conventionally known transformer-coupled plasma (TCP), inductively-coupled plasma (ICP), capacitively-coupled plasma (CCP), electron cyclotron resonance plasma (ECR), etc., but since the ion flux and ion energy cannot be controlled independently in CCP plasma, a high-density plasma other than CCP plasma is usually used to control the electron density to approximately 10 ¹⁰ to 10 ¹³ /cm ^3. The above process can be performed at a pressure of preferably 0.6 Pa or more, more preferably 2 Pa or more, and at a power level of preferably 1 kW or less, more preferably 500 W or less. The flow rate is preferably 40 to 1000 standard cubic centimeters per minute (sccm), and more specifically, can be set to a flow rate of about 500 sccm for preferably 1 to 3000 seconds, more preferably 10 to 600 seconds. The temperature can be set preferably to 0 to 300° C., more preferably 30 to 120° C.

<7: Patterning of electrode layer>
Next, using the patterning layer 14a as a mask, the electrode layer 12 exposed from the non-EUV irradiated portion removed to form the patterning layer 14a is removed, for example, by plasma etching, to pattern the electrode layer 12 as shown in FIG. 2(c).

<8: Patterning of insulating layer>
Then, the insulating layer 11 is patterned by removing the insulating layer 11 exposed from the removed portion of the electrode layer 12 for the patterning and the EUV non-irradiated portion 13b of the organic hydroxyoxotin layer 13 thereunder. The insulating layer 11 and the EUV non-irradiated portion 13b can be removed simultaneously or successively, for example, by plasma dry etching. That is, as shown in FIG. 2C, the EUV non-irradiated portion 13b of the organic hydroxyoxotin layer 13 formed previously is disposed under the insulating layer 11, and in this portion, uncured organic hydroxyoxotin exists in an unstable state, and the density of molecules is low. Therefore, the etching gas easily passes through the insulating layer 11 in the thickness direction, and even if the insulating layer 11 is formed of a material that is difficult to etch, this portion of the insulating layer 11 can be efficiently etched away. The EUV non-irradiated portion 13b of the organic hydroxyoxotin layer 13 thereunder can also be easily removed by using a reactive gas corresponding to ashing.

More specifically, as conditions for the plasma dry etching, it is effective to perform plasma etching while sequentially changing the reactive gas corresponding to etching and ashing so that both the insulating layer 11 and the EUV non-irradiated portion 13b (resist layer) of the organic hydroxyoxotin layer 13 can be removed. In this case, for example, the insulating layer 11 can be removed by etching using a plasma process using boron trichloride (BCl ₃ ), and then ashing can be performed using a plasma process using hydrogen halide (HX) or chlorine gas (Cl ₂ ). Ashing can also be performed using high-concentration BCl ₃ .
When etching the insulating layer 11 and ashing the non-EUV irradiated portion 13b (resist) are performed simultaneously, simultaneous etching and ashing can be performed, for example, by using an ECR plasma device and a mixed gas of _BCl3 and _Cl2 ( _Cl2 content is 60 volume % or less).

In addition, if the non-EUV irradiated portion 13b is a very thin film, there is no need to carry out etching and ashing in stages while changing the reactive gas, and the two layers 11 and 13b can be removed in a single process.

<9: Removal of Patterning Layer>
Next, the patterning layer 14a on the insulating layer 11 is removed by ashing using an acid. The ashing can be performed using an acid gas in accordance with plasma dry etching, as in the case of removing the EUV non-irradiated portion 13b of the organic hydroxyoxotin layer 13 described above.

In this way, as shown in FIG. 2(d), the insulating layer 11 and the electrode layer 12 are laminated in this order on the substrate 10 via the EUV irradiated portion 13a of the organic hydroxyoxotin layer 13, thereby obtaining a patterned substrate having a predetermined pattern.

According to the above-mentioned method for manufacturing a patterned substrate, when patterning the insulating layer 11, the EUV non-irradiated portion 13b of the organic hydroxy tin layer 13 provided under the insulating layer 11 is used for patterning, so that even if the insulating layer 11 is made of a material that is difficult to etch, it can be patterned efficiently. In addition, since the EUV irradiated portion 13a of the organic hydroxy tin layer 13 is sandwiched between the substrate 10 and the insulating layer 11, even if the substrate 10 and the insulating layer 11 are made of a material whose interface characteristics are easily unstable, the two can be laminated and integrated in a stable state through the EUV irradiated portion 13a. Moreover, when the insulating layer 11 is etched away, the surface of the substrate 10 is covered with the EUV non-irradiated portion 13b of the organic hydroxy tin layer 13, so that the surface of the substrate 11 can be protected from over-etching. In addition, as soon as the etching removal of the insulating layer 11 is completed, the non-EUV irradiated portion 13b of the organic hydroxyoxotin layer 13 is quickly removed, so there is no time lag and it is considered to be efficient.

The patterned substrate thus obtained has stable electrical properties because the insulating layer 11 is patterned efficiently in a short time, and no extra load is placed on the substrate 10 or the electrode layer 12. In particular, even in the case of a patterned substrate using a difficult-to-etch material with a high relative dielectric constant κ as the insulating layer 11, the substrate has particularly excellent electrical properties because it is efficiently manufactured.
Furthermore, the substrate is protected from over-etching, providing stable quality.

In the above embodiment, the patterning of the insulating layer 11 (the eighth step) and the removal of the patterning layer 14a derived from the second organic hydroxyoxotin layer 14 (the ninth step) are described as being performed in a sequential and stepwise manner, but depending on the etching conditions, the removal of the insulating layer 11 and the EUV non-irradiated portion 13b derived from the organic hydroxyoxotin layer 13 thereunder in the eighth step and the removal of the patterning layer 14a in the ninth step can be performed simultaneously at once. In this case, it is preferable to perform the plasma treatment using a mixed gas of _BCl3 and _Cl2 under high output of, for example, 600 W or more (higher output than the above-mentioned "gentle plasma treatment") and high plasma density. In addition, in order to obtain reaction selectivity with silicon, _O2 or _H2 may be mixed depending on the plasma process.

In the above embodiment, the organic hydroxyoxotin layer 13 and the second organic hydroxyoxotin layer 14 do not necessarily have to be the above organic hydroxyoxotin layers, and may be any type of organic resist material layer that can be handled in the same manner as in the above embodiment. For example, known organometallic compound resist materials using metals other than tin, polymer resist materials, metal oxide resist materials, etc. may be used.

In addition, in the above embodiment, the series of manufacturing steps shown in Figures 1(a) to (d) and Figures 2(a) to (d) are performed consecutively in order, but the series of steps do not necessarily need to be performed consecutively. A separately manufactured intermediate may be prepared and processed to obtain a patterned substrate. An example of the intermediate is a substrate 10 having an organic resist material layer 13 with EUV irradiated portions 13a and EUV non-irradiated portions 13b formed thereon by patterned irradiation with EUV (the stage of Figure 1[c]).

Another intermediate product is one in which an electrode layer 12 is formed on the insulating layer 11 (at the stage shown in FIG. 1[d]). And yet another intermediate product is one in which a patterning layer 14a is formed on the electrode layer 12 (at the stage shown in FIG. 2[b]).

By using these patterned substrate intermediates, the production process for patterned substrates can be divided into separate tasks depending on the size of the factory and the equipment, etc., and patterned substrates can be manufactured efficiently.

The present invention will be specifically explained below with reference to examples. However, the present invention is not limited in any way to the following examples.

[1. Formation of organic resist material layer]
An organic hydroxyoxotin layer is used as the organic resist material layer. A silicon substrate having a thickness of 50 μm is prepared as the substrate, and an organic hydroxyoxotin layer having a thickness of 10 nm is formed thereon by a CVD method using isopropyltris(dimethylamino)tin, which is a precursor of the organic hydroxyoxotin layer (see FIG. 1[a]). The conditions of the CVD method are as follows:
Pressure during film formation: 133 Pa (1 Torr)
Film formation temperature: 120° C. (wafer stage temperature)

[2: Pattern irradiation of organic resist material layer]
The organic resist material layer is irradiated with EUV in a pattern to obtain a cured EUV-irradiated portion and an uncured EUV-unirradiated portion (see FIG. 1[b]). The thickness (t1) of the organic resist material layer after EUV irradiation is 10 nm. The EUV irradiation conditions are as follows:
Light source: Extreme ultraviolet (EUV) (wavelength 13.5 nm)
Irradiation dose: 50 mJ/ ^cm2

[3. Formation of insulating layer]
Next, an insulating layer made of hafnium oxide (dielectric constant κ=15) is formed by an RF plasma (high frequency) method on the substrate having the pattern-irradiated organic resist material layer (see FIG. 1[c]). Note that the thickness (t2) of the insulating layer is 15 nm, and the thickness (t1) of the organic resist material layer (after EUV irradiation) is 10 nm, so t1/t2=0.67.

[4: Formation of electrode layer]
Next, a 20 μm-thick electrode layer made of polysilicon is formed on the insulating layer by CVD (see FIG. 1[d]).

[5: Formation of second organic resist material layer]
An organic hydroxyoxotin layer is used as the second organic resist material layer. Then, a second organic hydroxyoxotin layer having a thickness of 15 nm is formed on the electrode layer by CVD using tris(dimethylamino)isopropyltin, which is a precursor of the organic hydroxyoxotin layer (see FIG. 2[a]). The conditions of the CVD method are as follows:
Pressure during film formation: 133 Pa (1 Torr)
Film formation temperature: 120° C. (wafer stage temperature)

[6: Formation of patterning layer]
Next, the second organic resist material layer is pattern-irradiated with EUV in the same manner as in the above-mentioned step [2: Pattern-irradiation of organic resist material layer]. Then, the uncured portion (non-EUV irradiated portion) of the second organic resist material layer after EUV irradiation is removed using a plasma dry etching process, and the cured portion is developed to obtain a patterned layer (see FIG. 2[b]). The etching conditions are as follows:
Etching gas: HCl
Pressure: 2.6 Pa (20 mTorr)
Gas flow rate: 200 sccm
Temperature: 80°C
Output: 400W

7. Patterning of electrode layer
Next, the electrode layer is patterned by removing the portions of the electrode layer exposed from the non-EUV irradiated portions that have been removed to form the patterning layer by plasma dry etching (see FIG. 2[c]).

[8.9.10: Removal of non-EUV irradiated portions of patterning layer, insulating layer, and organic resist material layer on substrate]
The three layers, namely, the patterning layer, the insulating layer, and the non-EUV irradiated portion of the organic resist material layer on the substrate, are removed at once by dry etching using an ECR plasma device (see FIG. 2[d]). The etching conditions are as follows:
Etching gas: _BCl3 and _Cl2 mixed gas ( _Cl2 60% by volume)
Pressure: 40 Pa (300 mTorr)
Gas flow rate: 600 sccm
Output: 800W
Treatment time: 1 to 10 minutes Temperature: 30 to 80°C

According to the above embodiment, even though the insulating layer is made of hafnium oxide, which is difficult to etch, it can be smoothly etched away. Therefore, according to this method, it is possible to efficiently provide patterned substrates using various types of difficult-to-etch materials as the insulating layer, not limited to the above-mentioned hafnium oxide.

The method for manufacturing a patterned substrate of the present invention is useful in that it is possible to manufacture a patterned substrate with excellent electrical properties using a material that is difficult to etch as an insulating layer. Furthermore, the patterned substrate can be widely used in a wide variety of semiconductor devices, such as transistors.

REFERENCE SIGNS LIST 10: Substrate 11: Insulating layer 12: Electrode layer 13: Organic hydroxyoxotin layer (organic resist material layer)
13a EUV irradiated portion 13b EUV non-irradiated portion 14 Second organic hydroxyoxotin layer (second organic resist material layer)
14a Patterning layer

Claims (12)

A method for producing a patterned substrate having an insulating layer and an electrode layer laminated in this order on a substrate, comprising the steps of:
forming an organic resist material layer;
A step of irradiating the organic resist material layer with EUV in a pattern to obtain an EUV irradiated portion and an EUV non-irradiated portion;
forming an insulating layer on the substrate having the organic resist material layer that has been pattern-irradiated with EUV;
forming an electrode layer on the insulating layer;
forming a second organic resist material layer on the electrode layer;
a step of irradiating the second organic resist material layer with EUV in a pattern to obtain an EUV irradiated portion and an EUV non-irradiated portion, and then removing the EUV non-irradiated portion and developing the EUV irradiated portion to obtain a patterned layer;
removing the electrode layer exposed from the portion where the EUV non-irradiated portion has been removed;
removing an insulating layer exposed from a portion from which the electrode layer has been removed and a portion of the organic resist material layer that is not irradiated with EUV light and is below the insulating layer;
removing the patterning layer;
A method for manufacturing a patterned substrate having the above structure. The method for producing a patterned substrate according to claim 1, wherein the organic resist material layer and the second organic resist material layer are each a layer made of an organic hydroxyoxotin layer. 3. The method for producing a patterned substrate according to claim 2, wherein the organic hydroxyoxotin layer is formed using an organic hydroxyoxotin precursor represented by the following general formula (1):

[Chemical formula 1]
RSnX ₃ ... (1)
[R represents a hydrocarbon group having 1 to 30 carbon atoms, and X represents a hydrolyzable substituent.]
The method for manufacturing a patterned substrate according to claim 1 or 2, wherein the non-EUV irradiated portion is removed by acid. The method for manufacturing a patterned substrate according to claim 4, wherein the removal of the non-EUV irradiated portion is performed by a gas phase treatment using an acidic gas. The method for manufacturing a patterned substrate according to claim 1 or 2, wherein the insulating layer is formed from a material that is difficult to etch. The method for manufacturing a patterned substrate according to claim 6, wherein the difficult-to-etch material is a high-κ material having a relative dielectric constant κ of 9 or more. The method for manufacturing a patterned substrate according to claim 7, wherein the high-κ material having a relative dielectric constant κ of 9 or more is at least one compound selected from the group consisting of hafnium oxide, hafnium silicate nitride, hafnium aluminate, zirconium oxide, tantalum oxide, aluminum zirconium oxide, aluminum oxide, lanthanum oxide, and compounds of these with silica aluminum. A patterned substrate obtained by the method for producing a patterned substrate according to claim 1 or 2, in which an insulating layer and an electrode layer are formed in this order on a substrate having an EUV irradiated portion of an organic resist material layer. An intermediate for obtaining the patterned substrate according to claim 9, in which an insulating layer is formed on a substrate having an organic resist material layer in which an EUV irradiated portion and an EUV non-irradiated portion are formed. The patterned substrate intermediate of claim 10, having an electrode layer on the insulating layer. The patterned substrate intermediate of claim 11, having a patterning layer on the electrode layer.

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