KR20180029384A - Pellicle for an Extreme Ultraviolet(EUV) Lithography and method for fabricating the same - Google Patents

Abstract

According to the present invention, provided is a pellicle for a photomask in which gravity deflection is prevented and mechanical properties are improved by forming a pellicle layer including a support structure pattern arranged in a rugged honeycomb shape or a mesh shape on the upper surface, and in which thermal characteristics are improved by forming a support protective layer having excellent thermal emissivity on the support structure pattern. The pellicle for extreme ultraviolet (EUV) lithography according to the present invention comprises at least a lower reinforcing layer and a pellicle layer having the support structure pattern provided on the lower reinforcing layer, wherein the support structure pattern has a structure in which a cross-sectional shape has a rugged shape and a planar shape is arranged in one form of a honeycomb shape and a mesh shape.

Description

TECHNICAL FIELD The present invention relates to a pellicle for extreme ultraviolet lithography and a method for manufacturing the same.

The present invention relates to a pellicle for extreme ultraviolet lithography and a method for producing the same. More particularly, the present invention relates to a pellicle for extreme ultraviolet lithography capable of preventing sagging due to gravity of a pellicle layer and improving mechanical and thermal properties, .

Exposure technology using existing ArF wavelength (193 nm) utilizes Immersion Lithography technology to improve resolution, double patterning to reduce line width by a multi-turn process, and quadruple patterning techniques. Thereby realizing a circuit line width of 32 nm or less. However, due to problems such as process complexity and high cost of the above techniques, extreme ultraviolet lithography using extreme ultraviolet (EUV) with a wavelength of 13.5 nm is a next-generation exposure process technology for realizing a microcircuit line width It is attracting attention.

Accordingly, in order to prevent impurities from adhering to the surface of the photomask, a method of attaching a pellicle to the top of the photomask is performed. In recent years, as the circuit line width becomes finer, the size of impurities which may affect the pattern damage is also reduced, and thus the role of the pellicle for protecting the photomask becomes more important, and it is becoming an essential element in the photolithography technology.

The pellicle is basically composed of a pellicle layer having an ultrathin film thickness of 50 nm or less in order to secure an excellent transparency to extreme ultraviolet ray exposure light. The pellicle layer must ensure the vacuum environment, the mechanical reliability of the stage moving acceleration, the thermal reliability to withstand the exposure process accompanied by the high thermal energy, and the constituent materials and structure are determined in consideration of these factors.

The pellicle layer may be embodied in various forms including monolayer and multilayer forms. The pellicle layer in the form of a single membrane is generally formed of a substance having a low extinction coefficient with respect to an extreme ultraviolet ray exposure of 13.5 nm so that it is easy to secure transparency. However, it is extremely difficult to secure mechanical properties. Which is very vulnerable to deflection and breakage caused by the deflection.

In addition, when the pellicle layer is formed in the form of a multilayer film to compensate for the insufficient mechanical performance of the single-film pellicle layer, the mechanical strength can be improved as compared with the single film type. However, It is difficult to prevent sag due to gravity and damage caused by gravity similarly to the film form.

The present invention provides a pellicle for extreme ultraviolet lithography, which can prevent the pellicle layer from being sagged by gravity and can solve the problem of lowering the uniformity of the transmittance, and a method of manufacturing the same.

The present invention further provides a pellicle for extreme ultraviolet lithography which further enhances the mechanical properties of the pellicle and has excellent thermal properties, and a method for producing the same.

The pellicle for extreme ultraviolet lithography according to the present invention includes a pellicle layer, the pellicle layer including a support structure pattern provided on a lower reinforcement layer and the lower reinforcement layer, wherein the support structure pattern has a concavo- , And the planar shape is a honeycomb or mesh shape.

And a center layer provided between the lower reinforcement layer and the support structure pattern.

And a support protective layer covering the support structure pattern.

The support structure pattern has an interval of 1 占 퐉 to 100 占 퐉 between the center points of the patterns, and the pattern line has a line width of 0.1 占 퐉 to 10 占 퐉.

The present invention provides a pellicle layer having a concave-convex honeycomb structure or a mesh-like support structure on a top surface thereof, thereby preventing a phenomenon of gravity sagging and improving a mechanical property of a pellicle for an ultraviolet ray photomask .

In addition, the present invention can provide a pellicle for extreme ultraviolet ray photomask which can easily transmit extreme ultraviolet ray exposure light as the supporting structure pattern has a thickness of nano unit.

In addition, the present invention can provide a photomask pellicle having improved thermal characteristics by forming a support protective layer having excellent thermal emissivity on a support structure pattern.

1 is a cross-sectional view of a pellicle for extreme ultraviolet lithography according to a first embodiment of the present invention.
2 is a cross-sectional view illustrating a support structure pattern according to an embodiment of the present invention;
3 is a cross-sectional view of a pellicle for extreme ultraviolet lithography according to a second embodiment of the present invention.
4 is a cross-sectional view of a pellicle for extreme ultraviolet lithography according to a third embodiment of the present invention.
5 is a cross-sectional view of a pellicle for extreme ultraviolet lithography according to a fourth embodiment of the present invention.
6 is a cross-sectional view illustrating a method of manufacturing a pellicle for extreme ultraviolet lithography according to a second embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the drawings, but it should be understood that the present invention is not limited to these embodiments. For example, And is not intended to limit the scope of the invention. Therefore, it will be understood by those skilled in the art that various modifications and other equivalent embodiments may be made by those skilled in the art. Accordingly, the true scope of protection of the present invention should be determined by the technical matters of the claims.

FIG. 1 is a cross-sectional view showing a pellicle for extreme ultraviolet lithography according to a first embodiment of the present invention, and FIG. 2 is a cross-sectional view showing a support structure pattern according to an embodiment of the present invention.

1, a pellicle 100 for extreme ultraviolet lithography according to an embodiment of the present invention includes a pellicle layer 150 comprising a support layer pattern 102a, a lower stiffening layer 104, and a support structure pattern 108a .

The support layer pattern 102a is disposed at an edge portion of the lower reinforcement layer 104 and serves to support the pellicle layer 150. For example, the support layer pattern 102a can be formed by processing a silicon (Si) wafer by an etching process or the like.

The lower stiffening layer 104 reinforces the strength of the pellicle layer 150 and serves as an etch mask during the etch process to form the pellicle 100, including formation of the support layer pattern 102a.

The lower reinforcing layer 104 may be formed of silicon (Si) compound containing at least one of carbon (C) and nitrogen (N), silicon carbide (B ₄ C), graphene (Al ₂ O ₃ ), aluminum nitride (AIN), hafnium oxide (HfO ₂ ), and the like.

The lower stiffening layer 104 has a thickness of 2 nm to 10 nm. When the lower reinforcing layer 104 has a thickness of 2 nm or less, the strength of the thin film may be lowered and it is difficult to serve as an etching stopper film in the etching process. In addition, in the case of having a thickness of 10 nm or more, the transmittance to extreme ultraviolet ray exposure light is remarkably decreased, and the application is impossible.

The support structure pattern 108a serves to improve the mechanical properties of the pellicle layer 150 to prevent sagging of the pellicle layer 150 by gravity and to prevent breakage of the pellicle layer 150. [

To this end, the support structure pattern 108a has a structure in which the cross-sectional shape has a concave-convex shape and the planar shape is arranged in a honeycomb or mesh shape. The support structure pattern 108a has a thickness of 20 nm to 50 nm on the basis of the cross-sectional shape, and has a nano unit thickness, so that the extreme ultraviolet ray exposure light is easily transmitted. The concavo-convex pattern is formed by an upper surface and an etched lower surface through a patterning process including a thin film deposition and etching process, and the etching for forming the concave-convex shape corresponds to the case where the lower surface corresponds to 10% of the upper surface thickness And is completely etched so that the lower stiffening layer 104 is exposed from the depth.

2, the supporting structure pattern 108a has a structure arranged in a honeycomb or mesh form. The larger the spacing a based on the center point of the honeycomb or mesh patterns is, The characteristic is excellent, and as the line width (b) of the pattern line is larger, the mechanical characteristics such as the supporting function with respect to the pellicle 100 are enhanced. Accordingly, the support structure pattern 108a should be arranged in an optimized pattern structure so that excellent optical characteristics and mechanical characteristics can be sufficiently expressed, and the interval a between the patterns is preferably 1 mu m to 100 mu m The pattern line preferably has a line width (b) of 0.1 占 퐉 to 10 占 퐉, more preferably 0.2 占 퐉 And a line width (b) of 5 mu m.

In addition, the supporting structure pattern 108a minimizes the thermal damage to the high energy extreme ultraviolet ray exposure light during the manufacturing process of the pellicle layer 150.

For this purpose, the supporting structure pattern 108a may be formed of a carbon compound such as silicon carbide (SiC), boron carbide (B ₄ C), or graphene excellent in heat radiation property, aluminum oxide (Al ₂ O ₃ ) (AIN), hafnium oxide (HfO ₂ ), or the like.

3 is a cross-sectional view showing a pellicle for an EUV photomask according to a second embodiment of the present invention.

3, a pellicle 200 for extreme ultraviolet lithography according to an embodiment of the present invention includes a support layer pattern 102a and a lower reinforcement layer 104, a support structure pattern 108a, and a support structure pattern 108a. And a pellicle layer 150 made of a support protective layer 112 provided thereon. Here, the support layer pattern 102a and the lower reinforcement layer 104 are physically, chemically, and optically identical to the first embodiment described above.

The support protective layer 112 protects the support structure pattern 108a from damages due to the process and environmental influences during the process of manufacturing the pellicle layer 150 and ensures thermal reliability for high energy extreme ultraviolet exposure light Role. In particular, the support protective layer 112 should have excellent thermal properties to minimize thermal damage to other films constituting the underlying pellicle layer 150 as it is first exposed to extreme ultraviolet exposure light.

For this, the support protective layer 112 may be formed of a carbon compound such as silicon carbide (SiC), boron carbide (B ₄ C), or graphene excellent in heat radiation property, aluminum oxide (Al ₂ O ₃ ) (AIN) or hafnium oxide (HfO ₂ ), and has a thickness of 1 nm to 5 nm.

Like the first embodiment, the supporting structure pattern 108a has a concavo-convex cross-sectional shape and a planar shape arranged in a honeycomb or mesh form, and has a thickness of 20 nm to 50 nm.

The support structure pattern 108a preferably serves to further strengthen the mechanical strength as the support protective layer 112 plays a role in enhancing the thermal characteristics. For this purpose, a single crystal silicon (c-Si), a polycrystalline silicon p-Si), or a silicon (Si) compound containing at least one of carbon (C) and nitrogen (N) in the silicon (Si).

The support structure pattern 108a may be formed to have a concavo-convex structure such that the lower reinforcement layer 104 is exposed as the mechanical strength is partially enhanced by the support protective layer 112. [

FIG. 4 is a cross-sectional view illustrating a pellicle for an extreme ultraviolet ray photomask according to a third embodiment of the present invention, and FIG. 5 is a cross-sectional view illustrating a pellicle for an extreme ultraviolet ray photomask according to the fourth embodiment of the present invention.

4 and 5, the extreme ultraviolet lithography pellicle 300, 400 according to the embodiment of the present invention includes the lower reinforcement layer 104 and the support structure pattern 108a in the structures of the first and second embodiments described above, The pellicle layer 150 may be formed of a material having a high refractive index. Here, the support layer pattern 102a and the lower reinforcement layer 104 are the same as those of the first or second embodiment described above physically, chemically, or optically, and the structures of the support structure pattern 108a and the support protection layer 112 are the same Do.

The central layer 106 serves to ensure the mechanical strength of the pellicle 300, 400 and has a thickness of 20 nm to 50 nm to minimize the reduction of the transmittance to extreme ultraviolet exposure light and has an extreme ultraviolet EUV of 13.5 nm And has a transmittance of at least 80% or more with respect to exposure light.

The center layer 106 may be formed of single crystal silicon (c-Si), polycrystalline silicon (p-Si) or carbon (C) and nitrogen (N) with high transmittance to extreme ultraviolet ray exposure light and high mechanical strength. (Si) < / RTI >

The support structure pattern 108a can reduce its thickness as the center layer 106 secures the mechanical strength of the pellicle layer 50, and preferably has a thickness of 5 nm to 20 nm. Here, when the support structure pattern 108a has a thickness of 5 nm or less, it is difficult to mechanically support the pellicle layer 150, and when the support structure pattern 108a has a thickness of 20 nm or more, the transmittance to extreme ultraviolet ray exposure light It becomes a factor to drop remarkably and it is impossible to apply.

Referring to FIG. 4, the support structure pattern 108a may be formed of silicon carbide (SiC), boron carbide (B ₄ C), graphene (B ₄ C), or the like having excellent heat radiation characteristics to minimize thermal damage to high energy ultra- (Al ₂ O ₃ ), aluminum nitride (AIN), hafnium oxide (HfO ₂ ), and the like.

Referring to FIG. 5, the supporting structure pattern 108a serves to further strengthen the mechanical strength as the upper support protective layer 112 plays a role for enhancing the thermal property, as in Embodiment 2 described above And is made of a silicon (Si) compound containing at least one of carbon (C) and nitrogen (N) in a single crystal silicon (c-Si), a polycrystalline silicon .

As described above, according to the present invention, by forming the pellicle layer including honeycomb of concavo-convex shape or supporting structure pattern arranged in a mesh form, it is possible to prevent the phenomenon of sagging due to gravity of the pellicle, Further, by forming a support protective layer having excellent thermal emissivity on the support structure pattern, the thermal properties of the pellicle can be improved.

6 is a cross-sectional view illustrating a method of manufacturing a pellicle for EUV lithography according to a second embodiment of the present invention.

6A, a supporting layer 102 used as a base for manufacturing a pellicle for extreme ultraviolet lithography according to the present invention is prepared, and a lower reinforcing layer 104 and a supporting structure layer 102 are formed on one surface of the supporting layer 102. [ And a lower mask layer 110 is formed on the other surface.

The support layer 102 may be formed of silicon having a crystal orientation of, for example, [100] and having various sizes such as 6 inches and 8 inches with a doping density of 10 ²⁰ ions / cm ² or less and a thickness of 100 μm to 800 μm Si) wafer.

The lower reinforcing layer 104 is formed to a thickness of 2 nm to 10 nm and includes a silicon (Si) compound containing at least one of carbon (C) and nitrogen (N), silicon carbide (Al ₂ O ₃ ), aluminum nitride (AIN), and hafnium oxide (HfO ₂ ), such as a carbon compound such as B ₄ C or Graphene, or an insulator such as hafnium oxide .

The lower mask layer 110 serves as an etch mask for etching the support layer 102, which will be described later, and is formed to a thickness of 10 nm to 30 nm. The lower mask layer 110 is formed to include at least one of aluminum (Al), chromium (Cr), gold (Au), silicon nitride, and silicon oxide.

The lower reinforcing layer 104 and the lower mask layer 110 are formed by various methods such as chemical vapor deposition (CVD), sputtering, and atomic layer deposition (ALD).

The supporting structure layer 108 is formed to a thickness of 20 nm to 50 nm and is formed of a single crystal silicon (c-Si), a polycrystalline silicon (p-Si) (Si) compound containing at least one silicon atom.

The support structure layer 108 may be formed on the support structure layer 108 through epitaxy growth, chemical vapor deposition, sputtering, atomic layer deposition, ion beam deposition, electroplating, ).

Referring to FIG. 6B, a resist film 120a is formed on the supporting structure layer 108, and a resist film pattern 120a regularly arranged in a honeycomb or mesh shape is formed through the exposure and development processes. .

Then, the support structure layer 108 is etched by using the resist film pattern 120a as an etching mask to form a supporting structure pattern 108a in which irregular honeycomb or mesh patterns are regularly arranged. At this time, the supporting structure pattern 108a may be etched to various depths so that the portion to be etched is completely etched or partially remains. The wet etching can be performed by dry etching or wet etching, but it is preferable to use dry etching in order to secure uniformity between patterns and to avoid extensive etching damage after the wet etching.

Thereafter, a resist film pattern 120a exposing a region through which exposure light is transmitted is formed on one surface of the lower mask layer 110, and the lower mask layer 110 is etched using the resist film pattern 120a as an etching mask, The lower mask pattern 110a is formed on the bottom edge of the lower mask pattern 102. [

Here, the formation of the supporting structure pattern 108a and the lower mask pattern 110a can proceed regardless of their order.

Referring to FIG. 6C, after the resist film pattern is removed, a support protective layer 112 is formed on the support structure pattern 108a. The support protective layer 112 is formed to a thickness of 1 nm to 5 nm through chemical vapor deposition, sputtering, atomic layer deposition, or the like.

The support protective layer 112 may be formed of a carbon compound such as silicon carbide (SiC), boron carbide (B ₄ C), or graphene, which has excellent heat radiation properties, (Al ₂ O ₃ ), aluminum nitride (AIN), hafnium oxide (HfO ₂ ), or the like.

6 (d) and 6 (e), a portion of the supporting layer 102 exposed by the lower mask pattern 110a is etched to expose the lower stiffening layer 104 to form a transmissive region T is formed on the supporting layer pattern 102a.

Etching of the support layer 102 proceeds to dry etching process using KOH, wet or deep etcher using an etching solution of TMAH, etc. (Deep etcher), xenon Etcher (etcher XeF ₂₎ or the like. At this time, it is preferable that the etching process is performed in a state where a jig or a holder 200 (one-side etch jig or holder) is installed to cover at least the support protective layer 112 for protecting the upper support protective layer 112 Do. The support layer pattern 102a may have various shapes such as an inner cross-sectional shape that is inclined at a certain angle or a vertical shape depending on an etching method, characteristics, and the like. The resist film pattern 110a may be formed by a supporting layer 102). ≪ / RTI >

Thereafter, the jig or holder 130 is removed to complete the manufacture of a pellicle for an EUV photomask according to an embodiment of the present invention. Here, the lower mask pattern 110a may remain or be removed under the support layer pattern 102a.

While the present invention has been described with reference to the preferred embodiments, the technical scope of the present invention is not limited to the range described in the above embodiments. It will be readily apparent to those skilled in the art that various changes and modifications can be made to the embodiments described above. It is apparent from the description of the claims that the form of such modification or improvement can be included in the technical scope of the present invention.

100, 200, 300, 400: pellicle
102a: supporting layer pattern
104: Lower stiffening layer
106: center layer
108a: support structure pattern
110a: Lower mask pattern
112: support protective layer
120a: resist film pattern
130: holder
150: Pellicle layer

Claims (19)

1. A pellicle for extreme ultraviolet lithography comprising a pellicle layer,
Wherein the pellicle layer comprises a lower stiffening layer and a supporting structure pattern provided on the lower stiffening layer,
Wherein the support structure pattern has a concavo-convex shape in a cross-sectional shape, and a planar shape is arranged in one of a honeycomb shape and a mesh shape, for pellicle for extreme ultraviolet lithography.
1. A pellicle for extreme ultraviolet lithography comprising a pellicle layer,
Wherein the pellicle layer comprises a lower stiffening layer, a center layer sequentially disposed on the lower stiffening layer, and a support structure pattern,
Wherein the support structure pattern has a concavo-convex shape in a cross-sectional shape, and a planar shape is arranged in one of a honeycomb shape and a mesh shape, for pellicle for extreme ultraviolet lithography.
1. A pellicle for extreme ultraviolet lithography comprising a pellicle layer,
Wherein the pellicle layer includes a lower reinforcement layer, a support structure pattern disposed on the lower reinforcement layer, and a support protective layer covering the support structure pattern,
Wherein the support structure pattern has a concavo-convex shape in a cross-sectional shape, and a planar shape is arranged in one of a honeycomb shape and a mesh shape, for pellicle for extreme ultraviolet lithography.
1. A pellicle for extreme ultraviolet lithography comprising a pellicle layer,
Wherein the pellicle layer includes a lower reinforcement layer, a center layer sequentially disposed on the lower reinforcement layer, a support structure pattern, and a support protective layer covering the support structure pattern,
Wherein the support structure pattern has a concavo-convex shape in a cross-sectional shape, and a planar shape is arranged in one of a honeycomb shape and a mesh shape, for pellicle for extreme ultraviolet lithography.
5. The method according to any one of claims 1 to 4,
The lower reinforcing layer may be a silicon compound containing at least one of carbon (C) and nitrogen (N) in silicon, boron carbide (B ₄ C), graphene, aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AIN), and hafnium oxide (HfO ₂ ).
5. The method according to any one of claims 1 to 4,
Wherein the lower stiffening layer has a thickness of 2 nm to 10 nm.
5. The method according to any one of claims 1 to 4,
Wherein the supporting structure pattern has an interval of 1 占 퐉 to 100 占 퐉 between the center points of the patterns and the pattern line has a line width of 0.1 占 퐉 to 10 占 퐉.
3. The method according to claim 1 or 2,
Wherein the support structure pattern is completely etched so that the upper surface of the concavo-convex shape has a thickness of 20 nm to 50 nm and the etched lower surface is exposed from a depth corresponding to 10% of the upper surface thickness. Pellicle for extreme ultraviolet lithography.
3. The method according to claim 1 or 2,
The support structure pattern may include at least one of silicon carbide (SiC), boron carbide (B ₄ C), graphene aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AIN), and hafnium oxide (HfO ₂ ) And a pellicle for extreme ultraviolet lithography.
The method according to claim 3 or 4,
Wherein the support structure pattern is completely etched so that the upper surface of the concavo-convex shape has a thickness of 5 nm to 20 nm and the lower surface of the etched lower surface is exposed from a depth corresponding to 10% of the upper surface thickness. Pellicle for extreme ultraviolet lithography.
The method according to claim 3 or 4,
The support structure pattern is characterized by being made of a silicon (Si) compound containing at least one of carbon (C) and nitrogen (N) in single crystal silicon (c-Si), polycrystalline silicon Wherein the pellicle is an ultraviolet lithography pellicle.
The method according to claim 3 or 4,
The support protective layer may be formed of at least one of silicon carbide (SiC), boron carbide (B ₄ C), graphene aluminum oxide (Al ₂ O ₃ ), aluminum nitride (AIN), hafnium oxide (HfO ₂ ) And a pellicle for extreme ultraviolet lithography.
The method according to claim 3 or 4,
Wherein the support protective layer has a thickness of 1 nm to 5 nm. ≪ RTI ID = 0.0 > 8. < / RTI >
The method according to claim 2 or 4,
Wherein the center layer is made of a silicon (Si) compound containing at least one of carbon (C) and nitrogen (N) in a single crystal silicon (c-Si), a polycrystalline silicon Pellicle for extreme ultraviolet lithography.
The method according to claim 2 or 4,
Wherein the center layer has a thickness of 20 nm to 50 nm. ≪ RTI ID = 0.0 > 8. < / RTI >
5. The method according to any one of claims 1 to 4,
And a supporting layer pattern provided on a lower edge of the lower reinforcing layer.
17. The method of claim 16,
Further comprising a lower mask pattern disposed under the support layer pattern. ≪ RTI ID = 0.0 > 11. < / RTI >
18. The method of claim 17,
Wherein the lower mask pattern comprises at least one of Al, Cr, Au, silicon nitride, and silicon oxide.
18. The method of claim 17,
Wherein the lower mask pattern has a thickness of 20 nm to 50 nm.

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