Patent Description:
As the semiconductor industry continues to develop and the degree of semiconductor integration is dramatically improved, electronic devices are becoming smaller and lighter. In order to further improve the degree of semiconductor integration, the advancement of lithography technology is required.

Currently, technology is developing toward realizing a fine pattern of a semiconductor by reducing the wavelength of light. Extreme ultraviolet (EUV) lithography technology, recently developed as a next-generation technology, can realize a fine pattern through a single resist process.

An extreme ultraviolet lithography apparatus used in a semiconductor process includes a light source power, a resist, a pellicle, and a mask. The pellicle is installed on the mask to prevent contaminants generated during the lithography process from adhering to the mask, and is selectively used depending on the lithography machine.

In the extreme ultraviolet lithography process, there was an expectation that the pellicle would not be needed because a clean system was built. However, it has been known that during an actual operation after the construction of the lithography apparatus, contamination of the mask is caused by foreign substances generated from an internal driving unit of the apparatus, particles of tin generated in the oscillation of the light source, and extreme ultraviolet photoresist.

Therefore, in the extreme ultraviolet lithography process, the pellicle is recognized as an essential component so as to prevent contamination of the mask. When the pellicle is used, defects smaller than <NUM>,<NUM> in size are negligible.

The pellicle for extreme ultraviolet lithography is required to have a size of <NUM> × <NUM> to cover the mask, and an extreme ultraviolet transmittance of <NUM>% or more is required in order to minimize deterioration of productivity due to loss of a light source. In addition, mechanical stability that the pellicle is not damaged by physical movement up to <NUM> inside the extreme ultraviolet lithography apparatus, and thermal stability that the pellicle can withstand a thermal load of 250W or more based on a <NUM> node are required. Also, chemical durability that the pellicle does not react to hydrogen radicals generated in an extreme ultraviolet environment is required.

Currently, pellicle development companies are developing transmissive materials based on polycrystalline silicon (p-Si) or SiN. However, such materials do not satisfy a transmittance of <NUM>% or more, which is the most important condition of a pellicle for extreme ultraviolet lithography. Also, such materials have weaknesses in thermal stability, mechanical stability, and chemical durability in an extreme ultraviolet lithography environment, so that process development research is being conducted to supplement their properties. For example, materials such as Mo, Ru, and Zr have been selected and studied as materials for solving the problems of SiN-based materials, but it is difficult to manufacture a thin film and maintain its shape.

Recently, a pellicle having an extreme ultraviolet transmittance of <NUM>% or more and thermal, chemical, and mechanical stability in an extreme ultraviolet output environment of 350W or more, exceeding an irradiation intensity of 250W level, is required.

<CIT> describes a membrane, a patterning device assembly and a dynamic gas lock assembly for EUV lithography. The membrane may be a pellicle and comprises a base layer. In one embodiment, the base layer comprises YSi<NUM> or ZrSi<NUM>.

<CIT> describes a pellicle membrane for EUV lithography. The membrane may include Y<NUM>O<NUM> or SiO<NUM> material among others. A pellicle frame disposed on a surface of the membrane may include SiO<NUM> material among others. A heat emitting/release layer may include Y<NUM>O<NUM> or SiO<NUM> material among others.

<CIT> describes a pellicle for extreme ultraviolet (EUV) lithography. The pellicle comprises a support layer pattern, a buried oxide layer pattern provided on the support layer pattern, and a pellicle layer provided on the buried oxide layer pattern. The pellicle layer may be doped with one or more materials among boron (B), phosphorus (P), arsenic (As), yttrium (Y), zirconium (Zr), niobium (Nb) and molybdenum (Mo). The pellicle might further comprise a heat dissipation layer and a reinforcement layer.

<CIT> describes a membrane for EUV lithography comprising a stack. The stack may comprise a capping layer at an external surface of the membrane comprising a material selected from the group consisting of a transition metal silicide, a transition metal boride, a transition metal carbide, a transition metal nitride and a transition metal oxide.

The present disclosure provides an yttrium-based pellicle for extreme ultraviolet lithography according to independent device claim <NUM> having an extreme ultraviolet transmittance of <NUM>% or more in an extreme ultraviolet output environment of 350W or more.

In addition, the present disclosure provides an yttrium-based pellicle for extreme ultraviolet lithography having thermal stability, mechanical stability and chemical durability while having a high extreme ultraviolet transmittance of <NUM>% or more.

According to the invention, a pellicle for extreme ultraviolet lithography includes a pellicle layer including a core layer formed of an yttrium-based material expressed as Y-M (M is one of B, Si, O, and F).

In the pellicle, the yttrium-based material may include Y-Bx (x≥<NUM>), Y-Six (x≥<NUM>), Y<NUM>O<NUM>, or YF<NUM>.

In the pellicle, the yttrium-based material may include YB<NUM>, YB<NUM>, YB<NUM>, YB<NUM>, YB<NUM>, YB<NUM>, or YB<NUM>.

In the pellicle, the yttrium-based material may include YSi<NUM> or Y<NUM>Si<NUM>.

In the pellicle, the pellicle layer includes the core layer; and a capping layer formed on one or both surfaces of the core layer, wherein a material of the capping layer is expressed as Y-M-α (M is one of B, Si, O, and F, and α is one of Si, C, B, N, O, and Ru).

In the pellicle, the material of the capping layer includes YCxSiy (x+y≥<NUM>), YCxBy (x+y≥<NUM>), or YSixNy (x+y≥<NUM>), with x ≥ <NUM> and y ≥ <NUM>.

In the pellicle, the pellicle layer may include an intermediate layer formed on one or both surfaces of the core layer; and the capping layer formed on the intermediate layer, wherein a material of the intermediate layer may be expressed as Y-M-α (M is one of B, Si, O, and F, and α is one of Si, C, B, N, O, and Ru).

In the pellicle, the material of the intermediate layer includes YCxSiy (x+y≥<NUM>), YCxBy (x+y≥<NUM>), YSixNy (x+y≥<NUM>), YCx (x≥<NUM>), YSix (x≥<NUM>), YNx (x ≥<NUM>), SiNx (x≥<NUM>), SiO<NUM>, B<NUM>C, or RuC, with x≥<NUM> and y≥<NUM>.

According to embodiments of the present disclosure, a pellicle for extreme ultraviolet lithography may include a substrate having an opening formed in a central portion thereof; wherein the pellicle layer is formed on the substrate so as to cover the opening.

Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings. The present disclosure may, however, be embodied in many different forms and should not be construed as being limited to the embodiment set forth herein. Rather, this embodiment is provided so that the disclosure will be thorough and complete and will fully convey the scope of the disclosure to those skilled in the art. Accordingly, an embodiment described herein should be understood to include various modifications, equivalents, and/or alternatives.

In addition, techniques that are well known in the art and not directly related to the present disclosure are not described herein. This is to clearly convey the subject matter of the present disclosure by omitting an unnecessary explanation. Also, the terms are merely used for describing a particular embodiment but do not limit the embodiment.

<FIG> is a cross-sectional view showing an yttrium-based pellicle for extreme ultraviolet lithography according to a first embodiment of the present disclosure. <FIG> is an enlarged view of part A of <FIG>.

Referring to <FIG>, a pellicle <NUM> for extreme ultraviolet lithography according to the first embodiment (hereinafter referred to as 'pellicle') includes a substrate <NUM> having an opening <NUM> formed in its central portion, and a pellicle layer <NUM> formed on the substrate <NUM> so as to cover the opening <NUM> and including, as a core layer <NUM>, an yttrium-based material expressed as Y-M (M is one of B, Si, O, and F). The pellicle layer <NUM> includes the core layer <NUM> and capping layers <NUM> and <NUM> that are stacked on the substrate <NUM>. The capping layers <NUM> and <NUM> are formed on one or both surfaces of the core layer <NUM>.

The pellicle <NUM> is a consumable component that protects a mask from contaminants in a lithography process for semiconductor or display manufacturing. That is, the pellicle <NUM> is a thin film overlying the mask and serves as a cover. Because the light transferred to the wafer is focused with the mask in a lithographic exposure, even if contaminants exist on the pellicle <NUM> that is separated by a certain distance, it is possible to minimize a problem of forming a defective pattern due to out of focus.

As such, the pellicle <NUM> may minimize defective patterns while protecting the mask from contaminants during the exposure process, thereby greatly increasing the yield of semiconductor or display manufacturing. In addition, the use of the pellicle <NUM> can increase the lifespan of the mask.

Now, the pellicle <NUM> according to the present disclosure will be described in detail.

The substrate <NUM> supports the pellicle layer <NUM> and makes it easy to handle and transport the pellicle <NUM> during and after the process of manufacturing the pellicle <NUM>. The substrate <NUM> may be formed of a material such as silicon available for an etching process. For example, the material of the substrate <NUM> includes, but is not limited to, silicon, silicon oxide, silicon nitride, metal oxide, metal nitride, graphite, amorphous carbon, or a laminated structure of such materials. Here, metal may be, but is not limited to, Cr, Al, Zr, Ti, Ta, Nb, Ni, or the like.

The opening <NUM> in the central portion of the substrate <NUM> may be formed using a micro-machining technique such as micro-electro mechanical systems (MEMS). That is, the opening <NUM> is formed by removing the central portion of the substrate <NUM> by means of the micro-machining technique. The opening <NUM> partially exposes the pellicle layer <NUM>.

The pellicle layer <NUM> includes the core layer <NUM> and the capping layers <NUM> and <NUM>.

The core layer <NUM> is a layer that determines the transmittance of extreme ultraviolet rays. The core layer <NUM> has a transmittance of <NUM>% or more for extreme ultraviolet rays, and effectively dissipates heat to prevent overheating of the pellicle layer <NUM>.

The core layer <NUM> is formed of an yttrium-based material expressed as Y-M (M is one of B, Si, O, and F). The yttrium-based material includes Y-Bx (x≥<NUM>), Y-Six (x≥<NUM>), Y<NUM>O<NUM>, or YF<NUM>. Here, Y-Bx (x><NUM>) may include YB<NUM>, YB<NUM>, YB<NUM>, YB<NUM>, YB<NUM>, YB<NUM>, or YB<NUM>. Also, Y-Six (x≥<NUM>) may include YSi<NUM> or Y<NUM>Si<NUM>.

As shown in <FIG>, because Y-Bx (x><NUM>) has a high melting point like a metal-B material, and it has excellent thermal stability and high mechanical strength. Although Y-Bx (x><NUM>) may have various compositions, YB<NUM>, YB<NUM>, YB<NUM>, YB<NUM>, YB<NUM>, YB<NUM>, or YB<NUM> has a stable phase. For example, YB<NUM> has a melting point of about <NUM> and forms the most stable phase among Y-Bx (x≥<NUM>).

The reason for using the yttrium-based material as the material of the core layer <NUM> is as follows.

Using Y-M (M is one of B, Si, O, and F) material based on yttrium (Y) with chemical durability and mechanical stability as the material of the core layer <NUM> makes it possible to provide the pellicle <NUM> having an extreme ultraviolet transmittance of <NUM>% or more in an extreme ultraviolet output environment of 350W or more. That is, by depositing the Y-M material, which is a metal-based compound in which yttrium is combined with B capable of reinforcing mechanical strength, Si having high optical properties, or the like, on the substrate <NUM> to form the core layer <NUM>, it is possible to provide the pellicle <NUM> having an extreme ultraviolet transmittance of <NUM>% or more and a reflectance of <NUM>% or less.

In addition, the capping layers <NUM> and <NUM> provide thermal stability, mechanical stability, and chemical durability to the pellicle layer <NUM> while minimizing a decrease in the transmittance of the core layer <NUM> for extreme ultraviolet rays. Specifically, the capping layers <NUM> and <NUM> are protective layers for the core layer <NUM> and provide thermal stability by effectively dissipating heat generated in the core layer <NUM> to the outside. Also, the capping layers <NUM> and <NUM> provide mechanical stability by supplementing the mechanical strength of the core layer <NUM>. Further, the capping layers <NUM> and <NUM> provide chemical durability by protecting the core layer <NUM> from hydrogen radicals and oxidation.

The capping layers <NUM> and <NUM> are formed on one or both surfaces of the core layer <NUM>. The capping layers <NUM> and <NUM> according to the first embodiment include a first capping layer <NUM> formed on a lower surface of the core layer <NUM> and a second capping layer <NUM> formed on an upper surface of the core layer <NUM>.

The first capping layer <NUM> is interposed between the substrate <NUM> and the core layer <NUM>, is formed of a material having resistance to KOH, and prevents the material of the core layer <NUM> from diffusing into the substrate <NUM>.

The material of the first and second capping layers <NUM> and <NUM> includes a material expressed as Y-M-α (M is one of B, Si, O, and F, and α is one of Si, C, B, N, O, and Ru). For example, the Y-M-α material includes YCxSiy (x+y≥<NUM>),YCxBy (X+Y> <NUM>), or YSixNy (x+y≥<NUM>), x ≥ <NUM> and y ≥ <NUM>.

The reason for using the Y-M-α material as the material of the first and second capping layers <NUM> and <NUM> is as follows.

In a conventional pellicle, there was a need to form the capping layer to a thickness of <NUM> or less in order to ensure a high extreme ultraviolet transmittance. However, by using, as the material of the first and second capping layers <NUM> and <NUM>, the Y-M-α material in which the α material is added to the Y-M material used for the core layer <NUM>, it is possible to provide the pellicle <NUM> not only having a high extreme ultraviolet transmittance of <NUM>% or more but also having thermal stability, mechanical stability and chemical durability even if the capping layers <NUM> and <NUM> are formed to a thickness of <NUM>.

As such, the pellicle <NUM> according to the first embodiment including the Y-M material as the core layer <NUM> may provide thermal stability, mechanical stability, and chemical durability while having a high extreme ultraviolet transmittance of <NUM>% or more.

The above-described pellicle <NUM> according to the first embodiment may be manufactured by the following manufacturing process. First, in order to form the pellicle layer <NUM>, the first capping layer <NUM>, the core layer <NUM>, and the second capping layer <NUM> are sequentially stacked on the substrate <NUM> in which the opening <NUM> is not formed.

At this time, each of the first capping layer <NUM>, the core layer <NUM>, and the second capping layer <NUM> may be formed by a chemical vapor deposition (CVD) process, an atomic layer deposition (ALD) process, an e-beam evaporation process, or a sputtering process.

Thereafter, by removing the central portion of the substrate <NUM> under the pellicle layer <NUM> to form the opening <NUM> through which a lower surface of the pellicle layer <NUM> is partially exposed, the pellicle <NUM> according to the first embodiment can be obtained. That is, the opening <NUM> is formed by removing the central portion of the substrate <NUM> under the first capping layer <NUM> through wet etching. The opening <NUM> partially exposes the first capping layer <NUM>.

<FIG> is an enlarged view showing an yttrium-based pellicle for extreme ultraviolet lithography according to a second embodiment of the present disclosure.

Referring to <FIG>, a pellicle according to the second embodiment includes a substrate having an opening formed in its central portion, and a pellicle layer <NUM> formed on the substrate so as to cover the opening and including, as a core layer <NUM>, an yttrium-based material expressed as Y-M (M is one of B, Si, O, and F). The pellicle layer <NUM> may include the core layer <NUM>, an intermediate layer <NUM>, and capping layers <NUM> and <NUM> that are stacked on the substrate. Each of the intermediate layer <NUM> and the capping layers <NUM> and <NUM> may be formed on one or both surfaces of the core layer <NUM>.

The pellicle according to the second embodiment has the same structure as the pellicle (<NUM> in <FIG>) according to the first embodiment except that the intermediate layer <NUM> is added.

The capping layers <NUM> and <NUM> include a first capping layer <NUM> formed on a lower surface of the core layer <NUM> and a second capping layer <NUM> formed on an upper surface of the core layer <NUM>.

The material of the first and second capping layers <NUM> and <NUM> includes a material expressed as Y-M-α (M is one of B, Si, O, and F, and α is one of Si, C, B, N, O, and Ru). For example, the Y-M-α material includes YCxSiy (x+y≥<NUM>),YCxBy (x+y≥<NUM>), or YSixNy (x+y≥<NUM>) with x≥<NUM> and y≥<NUM>, or RuC.

The intermediate layer <NUM> is interposed between the core layer <NUM> and each of the capping layers <NUM> and <NUM>. The intermediate layer <NUM> functions as a protective layer for relieving thermal stress due to thermal expansion and preventing diffusion. The intermediate layer <NUM> may serve as a buffer layer to increase a bonding force between the core layer <NUM> and each of the capping layers <NUM> and <NUM> forming the interface. The intermediate layer <NUM> according to the second embodiment is an example of being formed between the core layer <NUM> and the second capping layer <NUM>.

The material of the intermediate layer <NUM> includes a material expressed as Y-M-α (M is one of B, Si, O, and F, and α is one of Si, C, B, N, O, and Ru). For example, the Y-M-α material may include YCxSiy (x+y≥<NUM>),YCxBy (x+y≥<NUM>),YSixNy (x+y≥<NUM>), YCx (x≥<NUM>), YSix (x≥<NUM>), YNx (x ≥<NUM>), SiNx (x≥<NUM>), SiO<NUM>, B<NUM>C, or RuC, with x≥<NUM> and y≥<NUM>.

As such, the pellicle according to the second embodiment including the Y-M material as the core layer <NUM> may provide thermal stability, mechanical stability, and chemical durability while having a high extreme ultraviolet transmittance of <NUM>% or more.

The above-described pellicle according to the second embodiment may be manufactured by the following manufacturing process. First, in order to form the pellicle layer <NUM>, the first capping layer <NUM>, the core layer <NUM>, the intermediate layer <NUM>, and the second capping layer <NUM> are sequentially stacked on the substrate <NUM> in which the opening <NUM> is not formed.

At this time, each of the first capping layer <NUM>, the core layer <NUM>, the intermediate layer <NUM>, and the second capping layer <NUM> may be formed by a CVD process, an ALD process, an e-beam evaporation process, or a sputtering process.

Thereafter, by removing the central portion of the substrate <NUM> under the pellicle layer <NUM> to form the opening through which a lower surface of the pellicle layer <NUM> is partially exposed, the pellicle according to the second embodiment can be obtained. That is, the opening is formed by removing the central portion of the substrate under the first capping layer <NUM> through wet etching. The opening partially exposes the first capping layer <NUM>.

<FIG> is an enlarged view showing an yttrium-based pellicle for extreme ultraviolet lithography according to a third embodiment of the present disclosure.

Referring to <FIG>, a pellicle according to the third embodiment includes a substrate having an opening formed in its central portion, and a pellicle layer <NUM> formed on the substrate so as to cover the opening and including, as a core layer <NUM>, an yttrium-based material expressed as Y-M (M is one of B, Si, O, and F). The pellicle layer <NUM> may include the core layer <NUM>, intermediate layers <NUM> and <NUM>, and capping layers <NUM> and <NUM> that are stacked on the substrate.

The pellicle according to the third embodiment has the same structure as the pellicle (<NUM> in <FIG>) according to the first embodiment except that the intermediate layers <NUM> and <NUM> are added.

The material of the first and second capping layers <NUM> and <NUM> includes a material expressed as Y-M-α (M is one of B, Si, O, and F, and α is one of Si, C, B, N, O, and Ru). For example, the Y-M-α material includes YCxSiy (x+y≥<NUM>),YCxBy (x+y≥<NUM>), or YSixNy (x+y≥<NUM>), with x≥<NUM> and y≥<NUM>.

The intermediate layers <NUM> and <NUM> are interposed between the core layer <NUM> and the capping layers <NUM> and <NUM>. The intermediate layers <NUM> and <NUM> function as a protective layer for relieving thermal stress due to thermal expansion and preventing diffusion. The intermediate layers <NUM> and <NUM> may serve as a buffer layer to increase a bonding force between the core layer <NUM> and the capping layers <NUM> and <NUM> forming the interface. The intermediate layers <NUM> and <NUM> according to the third embodiment include a first intermediate layer <NUM> formed between the core layer <NUM> and the first capping layer <NUM>, and a second intermediate layer <NUM> formed between the core layer <NUM> and the second capping layer <NUM>.

The material of the intermediate layers <NUM> and <NUM> includes a material expressed as Y-M-α (M is one of B, Si, O, and F, and α is one of Si, C, B, N, O, and Ru). For example, the Y-M-α material may include YCxSiy (x+y≥<NUM>),YCxBy (x+y≥<NUM>), YSixNy (x+y≥<NUM>),YCx (x≥<NUM>), YSix (x≥<NUM>), YNx (x ≥<NUM>), SiNx (x≥<NUM>), SiO<NUM>, B<NUM>C, or RuC, with x≥<NUM> and y≥<NUM>.

As such, the pellicle according to the third embodiment including the Y-M material as the core layer <NUM> may provide thermal stability, mechanical stability, and chemical durability while having a high extreme ultraviolet transmittance of <NUM>% or more.

The above-described pellicle according to the third embodiment may be manufactured by the following manufacturing process. First, in order to form the pellicle layer <NUM>, the first capping layer <NUM>, the first intermediate layer <NUM>, the core layer <NUM>, the second intermediate layer <NUM>, and the second capping layer <NUM> are sequentially stacked on the substrate <NUM> in which the opening <NUM> is not formed.

At this time, each of the first capping layer <NUM>, the first intermediate layer <NUM>, the core layer <NUM>, the second intermediate layer <NUM>, and the second capping layer <NUM> may be formed by a CVD process, an ALD process, an e-beam evaporation process, or a sputtering process.

Thereafter, by removing the central portion of the substrate <NUM> under the pellicle layer <NUM> to form the opening through which a lower surface of the pellicle layer <NUM> is partially exposed, the pellicle according to the third embodiment can be obtained. That is, the opening is formed by removing the central portion of the substrate under the first capping layer <NUM> through wet etching. The opening partially exposes the first capping layer <NUM>.

In order to check the transmittance and reflectance of the pellicle according to the present disclosure in an extreme ultraviolet output environment of 350W or more, simulations were performed on the pellicles according to first to sixth experimental examples as shown in <FIG>.

The pellicles according to the first to sixth experimental examples include the pellicle layer according to the first embodiment. That is, the pellicle layer includes the first capping layer, the core layer, and the second capping layer. The material of the first and second capping layers is SiNx. The material of the core layer is an yttrium-based material.

When the thickness of the first capping layer is <NUM>, the transmittance and reflectance of the pellicle according to each of the first to sixth experimental examples were simulated in an extreme ultraviolet output environment of 350W while changing the thickness of the core layer between <NUM> and <NUM> and the thickness of the capping layer between <NUM> and <NUM>.

The materials of the core layer according to the first to sixth experimental examples are Y, YB<NUM>, YB<NUM>, YB<NUM>, YB<NUM>, and YB<NUM>.

The pellicles according to the first to sixth experimental examples were expressed as "SiN_C(<NUM>)_YBx_SiN(<NUM>)". Here, 'SiN(<NUM>)' denotes the first capping layer. In addition, 'YBx' denotes the core layer, and x is <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>. Also, `C(<NUM>)' denotes the intermediate layer, but the intermediate layer was not applied in the first and sixth experimental examples. And 'SiN' denotes the second capping layer.

<FIG> is a graph showing transmittance and reflectance of an yttrium-based pellicle for extreme ultraviolet lithography according to a first experimental example of the present disclosure.

Referring to <FIG>, the pellicle according to the first experimental example was expressed as "SiN_C(Onm)_Y_SiN(<NUM>)".

When the thickness of the core layer is <NUM> or less and the thickness of the capping layer is <NUM> or less, the transmittance is <NUM>% or more.

In addition, when the thickness of the core layer is <NUM> or less and the thickness of the capping layer is <NUM> to <NUM> or <NUM> to <NUM>, it can be seen that the transmittance is <NUM>% or less.

<FIG> is a graph showing transmittance and reflectance of an yttrium-based pellicle for extreme ultraviolet lithography according to a second experimental example of the present disclosure.

Referring to <FIG>, the pellicle according to the second experimental example was expressed as "SiN_C(<NUM>)_YB2_SiN(<NUM>)".

<FIG> is a graph showing transmittance and reflectance of an yttrium-based pellicle for extreme ultraviolet lithography according to a third experimental example of the present disclosure.

Referring to <FIG>, the pellicle according to the third experimental example was expressed as "SiN_C(<NUM>)_YB4_SiN(<NUM>)''.

<FIG> is a graph showing transmittance and reflectance of an yttrium-based pellicle for extreme ultraviolet lithography according to a fourth experimental example of the present disclosure.

Referring to <FIG>, the pellicle according to the fourth experimental example was expressed as "SiN_C(<NUM>)_YB6_SiN(<NUM>)''.

<FIG> is a graph showing transmittance and reflectance of an yttrium-based pellicle for extreme ultraviolet lithography according to a fifth experimental example of the present disclosure.

Referring to <FIG>, the pellicle according to the fifth experimental example was expressed as "SiN_C(<NUM>)_YB12_SiN(<NUM>)".

<FIG> is a graph showing transmittance and reflectance of an yttrium-based pellicle for extreme ultraviolet lithography according to a sixth experimental example of the present disclosure.

Referring to <FIG>, the pellicle according to the sixth experimental example was expressed as "SiN_C(<NUM>)_YB66_SiN(<NUM>)".

As such, according to the first to sixth experimental examples, it can be seen that, by using the yttrium-based material as the material of the core layer, the pellicle having an extreme ultraviolet transmittance of <NUM>% or more and having a reflectance of <NUM>% or less can be provided.

Claim 1:
A pellicle (<NUM>, <NUM>, <NUM>) for extreme ultraviolet lithography, the pellicle comprising:
a pellicle layer (<NUM>) including a core layer (<NUM>) formed of an yttrium-based material expressed as Y-M, M being one of B, Si, O, and F, and a capping layer (<NUM>) formed on one or both surfaces of the core layer (<NUM>),
wherein a material of the capping layer (<NUM>) is expressed as Y-M-α, M being one of B, Si, O, and F, and α being one of Si, C, B, N, O, and Ru, characterized in that the material of the capping layer (<NUM>) includes YCxSiy (x+y≥<NUM>), YCxBy (x+y≥<NUM>), or YSixNy (x+y≥<NUM>), with x≥<NUM> and y≥<NUM>.