Protective film for extreme ultraviolet photomask and method for manufacturing the same

Abstract

A protective film for an extreme ultraviolet light photomask includes a first cover layer, a matrix layer disposed above the first cover layer, a second cover layer disposed above the matrix layer, and a metal layer disposed above the second cover layer.

Description

Technical Field

[0001] This disclosure relates to a protective film for photolithography masks and a method for manufacturing a protective film for extreme ultraviolet (EUV) photomasks. Background Technology

[0002] A protective pellicle is a thin, transparent film stretched over a frame and adhered to one side of the photomask to protect it from damage, dust, and / or moisture. In extreme ultraviolet (EUV) lithography, a protective pellicle with high transparency, high mechanical strength, and low thermal expansion is typically required in the EUV wavelength region. Summary of the Invention

[0003] This disclosure provides a protective film for an extreme ultraviolet (EUV) photomask, comprising: a first cover layer, a substrate layer, a second cover layer, and a metal layer. The substrate layer is disposed above the first cover layer. The second cover layer is disposed above the substrate layer. The metal layer is disposed above the second cover layer.

[0004] Another embodiment of this disclosure provides a protective film for an extreme ultraviolet (EUV) photomask, comprising: a first capping layer, a substrate layer, a stabilizing layer, a second capping layer, and a metal layer. The substrate layer is disposed above the first capping layer. The stabilizing layer is disposed above the substrate layer. The second capping layer is disposed above the stabilizing layer. The metal layer is disposed above the stabilizing layer.

[0005] Another aspect of this disclosure provides a method for manufacturing a protective film for an extreme ultraviolet (EUV) photomask. This method includes: forming a first cover layer above a front surface of a substrate; forming a first base matrix layer above the first cover layer; forming a second base matrix layer above the first base matrix layer; forming an alloy from the first base matrix layer and the second base matrix layer via a thermal operation as an alloy matrix layer; forming a second cover layer above the alloy matrix layer; forming a back-side coating above a back surface of the substrate; forming a first opening in the back-side coating via patterning the back-side coating; forming a second opening in the substrate by etching through the first opening; and forming one or more metal layers above the second cover layer.

[0006] Another embodiment of this disclosure provides a protective film for an extreme ultraviolet (EUV) photomask, comprising: a first cover layer, a first substrate layer, a second substrate layer, a second cover layer, and a metal layer. The first substrate layer is disposed above the first cover layer. The second substrate layer is disposed above the first substrate layer. The second cover layer is disposed above the second substrate layer. The metal layer is disposed above the second cover layer.

[0007] Another aspect of this disclosure provides a method for manufacturing a protective film for an extreme ultraviolet (EUV) photomask, the method comprising: forming a first cover layer above a front surface of a substrate; forming a matrix layer above the first cover layer; forming a second cover layer above the matrix layer; forming a back-side coating on a back surface of the substrate; forming a first opening in the back-side coating via patterning the back-side coating; forming a second opening in the substrate via etching the substrate through the first opening; and forming one or more metal layers above the second cover layer.

[0008] Another aspect of this disclosure provides a method for manufacturing a protective film for an extreme ultraviolet (EUV) photomask, the method comprising: forming a first layer above the front surface of a substrate; forming a second layer above the first layer; forming a third layer above the second layer; forming a fourth layer above the third layer; forming a back-side opening on the back side of the substrate; and forming a fifth layer above the fourth layer, wherein the fifth layer comprises one or more of Mo, Zr, Nb, B, Ti, Ru, MoSi, ZrSi, NbSi, or NiZrSi. Attached Figure Description

[0009] Various aspects of this disclosure can be described in detail below, and in conjunction with the appended documents. Figure 1 For optimal reading and understanding, please note that, according to industry standard practice, the features are not drawn to scale. In fact, for clarity of discussion, the dimensions of the features may be arbitrarily increased or decreased.

[0010] Figure 1 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to an embodiment of the present disclosure.

[0011] Figure 2 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to an embodiment of the present disclosure.

[0012] Figure 3 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to an embodiment of the present disclosure.

[0013] Figure 4 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to an embodiment of the present disclosure.

[0014] Figure 5 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to an embodiment of the present disclosure.

[0015] Figure 6A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to an embodiment of the present disclosure.

[0016] Figure 7 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to an embodiment of the present disclosure.

[0017] Figure 8 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to an embodiment of the present disclosure.

[0018] Figure 9 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to an embodiment of the present disclosure.

[0019] Figure 10 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to an embodiment of the present disclosure.

[0020] Figure 11 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to an embodiment of the present disclosure.

[0021] Figure 12 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0022] Figure 13 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0023] Figure 14 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0024] Figure 15 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0025] Figure 16 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0026] Figure 17A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0027] Figure 18 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0028] Figure 19 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0029] Figure 20 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0030] Figure 21 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0031] Figure 22 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0032] Figure 23 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0033] Figure 24 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0034] Figure 25 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0035] Figure 26 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0036] Figure 27 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0037] Figure 28A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0038] Figure 29 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0039] Figure 30 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0040] Figure 31 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0041] Figure 32 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0042] Figure 33 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0043] Figure 34 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0044] Figure 35 A cross-sectional view showing one of the stages of manufacturing a protective film for an extreme ultraviolet photomask according to another embodiment of this disclosure;

[0045] Figure 36 A cross-sectional view of a protective film for an extreme ultraviolet light mask according to another embodiment of this disclosure is shown;

[0046] Figure 37 A cross-sectional view of a protective film for an extreme ultraviolet light mask according to another embodiment of this disclosure is shown;

[0047] Figure 38 A cross-sectional view is shown, illustrating a protective film attached to an extreme ultraviolet light mask according to an embodiment of this disclosure.

[0048] [Symbol Explanation]

[0049] 10: Substrate

[0050] 15: Third opening

[0051] 20: First Covering Layer

[0052] 30: Matrix layer

[0053] 40: Second Covering Layer

[0054] 50: Backside coating

[0055] 55: Second opening

[0056] 60: Photoresist layer

[0057] 65: First Opening

[0058] 100: Metal layer

[0059] 130: Basic matrix layer

[0060] 140: Stable layer

[0061] 150: Basic Stabilization Layer

[0062] 160: Alloy layer

[0063] 200: Protective film

[0064] 210: Extreme Ultraviolet Photomask

[0065] 212: Black border

[0066] 214: Circuit Pattern Detailed Implementation

[0067] It is understood that the following disclosure provides many different implementations or embodiments for achieving various features of this disclosure. Specific implementations or embodiments of components and configurations are described below to simplify this disclosure. These are, of course, merely embodiments and are not intended to be limiting. For example, the dimensions of elements are not limited to the ranges or values ​​disclosed, but may depend on the process conditions and / or desired characteristics of the device. Furthermore, in the following description, forming a first feature above or on a second feature may include embodiments where the first and second features are formed in direct contact, and may also include embodiments where additional features may be formed between the first and second features, thus the first and second features may not be in direct contact. For simplicity and clarity, the various features may be drawn arbitrarily at different scales. In the accompanying drawings, some layers / features may be omitted for simplicity.

[0068] Furthermore, to facilitate the description of the relationship between one element or feature and another, as illustrated in the accompanying drawings, spatially relative terms such as "below," "below," "lower," "above," and "higher" may be used herein. In addition to the directions illustrated in the drawings, the spatially relative terms are intended to cover different orientations of the device in use or operation. The device may have other orientations (rotation 90 degrees or other orientations), and the spatially relative descriptive terms used herein may be interpreted accordingly. Furthermore, the term "made of" may mean either "comprising" or "consisting of." Moreover, in the following manufacturing process, one or more additional operations may exist between the described operations, and the order of operations may be changed. In this disclosure, the phrase "at least one of A, B, and C" refers to any one of A, B, C, A+B, A+C, B+C, or A+B+C, and does not mean one from A, one from B, and one from C, unless otherwise stated.

[0069] A protective film is a thin, transparent film stretched over a frame that is attached to the top of one side of the photomask. The protective film protects the photomask from particles, dust, damage, and / or contamination. Protective films typically require high transparency and low reflectivity. In ultraviolet (UV) or deep ultraviolet (DUV) lithography, the protective film layer is made of a transparent resin film. However, in extreme ultraviolet (DUV) lithography, resin-based films are unacceptable, and non-organic materials such as polycrystalline silicon, silicides, or graphite must be used.

[0070] In this disclosure, the protective film for extreme ultraviolet (EUV) photomasks has a stacked structure of various dielectric, semiconductor, and / or metallic materials to enhance EUV transmittance, reduce EUV reflectance, improve mechanical strength, and / or improve thermal performance. Specifically, the protective film according to this disclosure has, in some embodiments, an EUV transmittance greater than about 85%, and in other embodiments, an EUV transmittance greater than about 87%, and in some embodiments, an EUV reflectance less than about 0.25%, and in other embodiments, an EUV reflectance less than about 0.10%.

[0071] Figures 1 to 11 The sequential manufacturing operations of a protective film for an extreme ultraviolet (EUV) photomask according to an embodiment of this disclosure are shown. It is understood that... Figures 1 to 11 Additional operations are provided before, during, and after the process shown, and some of the operations described below may be replaced or eliminated in other embodiments of the method. The order of operations / processes may be interchangeable.

[0072] like Figure 1As shown, a substrate 10, such as a silicon (Si) wafer, is fabricated. In some embodiments, the thickness of the substrate 10 ranges from about 500 micrometers (μm) to about 1000 micrometers.

[0073] like Figure 2 As shown, a first capping layer 20 is formed on substrate 10. The first capping layer 20 serves as an etch stop layer in subsequent substrate etching operations. The first capping layer 20 comprises one or more layers of semiconductor material, such as SiC, SiGe, Ge; or dielectric material, such as silicon oxide, silicon nitride, silicon oxynitride, and SiCN; or any other suitable material. In some embodiments, SiC is formed on substrate 10 by epitaxial growth. In other embodiments, the first capping layer 20 may be an amorphous or polycrystalline SiC, SiGe, or Ge layer. In some embodiments, the first capping layer 20 is a silicon nitride. In some embodiments, the thickness of the first capping layer 20 ranges from about 0.5 nanometers (nm) to about 40 nanometers; in other embodiments, the thickness of the first capping layer 20 ranges from about 1 nanometer to about 20 nanometers. The first capping layer 20 can be formed via chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), molecular beam epitaxy (MBE), and any other suitable film formation method.

[0074] After the first capping layer 20 is formed, a matrix layer 30 is formed on top of the first capping layer 20, such as... Figure 3 As shown. In some embodiments, the matrix layer 30 comprises a semiconductor material, such as Si, SiC, SiGe; a metal alloy, such as a silicide (WSi, NiSi, TiSi, CoSi, MoSi, ZrSi, etc.); or a dielectric material, such as a silicon nitride. In some embodiments, the silicide layer is subjected to a nitriding or oxidation operation to form, for example, MoSiN, ZrSiN, MoSiO, or ZrSiO. The semiconductor material may be monocrystalline, polycrystalline, or amorphous. In some embodiments, the matrix layer 30 comprises a MoSi layer or a ZrSi layer. In some embodiments, the thickness of the matrix layer 30 is in the range of about 5 nanometers to about 50 nanometers, and in other embodiments, the thickness of the matrix layer 30 is in the range of about 20 nanometers to about 40 nanometers. The matrix layer 30 may be formed via chemical vapor deposition, physical vapor deposition, atomic layer deposition, molecular beam epitaxy, and any other suitable film formation method. After the formation of the matrix layer 30, in some embodiments, the operation is performed at about 250°C to about 1100°C.

[0075] Subsequently, a second cover layer 40 is formed above the matrix layer 30, such as... Figure 4 As shown. The second capping layer 40 comprises one or more layers of semiconductor material, such as SiC, SiGe, Ge; or dielectric material, such as silicon oxide, silicon nitride, silicon nitride, and SiCN; or any other suitable material. In some embodiments, the thickness of the second capping layer 40 ranges from about 0.5 nanometers to about 40 nanometers, and in other embodiments, the thickness of the second capping layer 40 ranges from about 1 nanometer to about 20 nanometers. The second capping layer 40 can be formed via chemical vapor deposition, physical vapor deposition, atomic layer deposition, molecular beam epitaxy, and any other suitable film formation method. The material of the second capping layer 40 may be the same as or different from the material of the first capping layer 20.

[0076] Next, as Figure 5 As shown, a back-side coating 50 is formed over the back side of the substrate 10. The back-side coating 50 comprises one or more layers of a dielectric material, such as silicon oxide, silicon nitride, silicon nitride, and SiCN. In other embodiments, a metal layer is used. In some embodiments, the thickness of the back-side coating 50 ranges from about 100 nanometers to about 1000 nanometers, and in other embodiments, the thickness of the back-side coating 50 ranges from about 200 nanometers to about 500 nanometers. The back-side coating 50 can be formed via chemical vapor deposition, physical vapor deposition, atomic layer deposition, molecular beam epitaxy, and any other suitable film formation method.

[0077] After that, as Figure 6 As shown, a photoresist layer 60 is formed on the back-side coating 50. In some embodiments, the thickness of the photoresist layer 60 ranges from about 1 micrometer to about 3 micrometers. One or more lithography operations are performed to pattern the photoresist layer 60, and the back-side coating 50 is subsequently patterned via one or more etching operations to form the first opening 65, as shown. Figure 7 As shown.

[0078] Subsequently, the back-side coating 50 is etched using a patterned photoresist layer 60 as an etching mask to form the second opening 55, as shown. Figure 8 As shown. Etching is one or more of dry etching and wet etching operations. The photoresist layer 60 is removed via a suitable photoresist removal operation, as shown. Figure 9 As shown.

[0079] Next, the substrate 10 is etched to form the third opening 15, as shown. Figure 10As shown. In some embodiments, wet etching is performed using KOH, tetramethylammonium hydroxide (TMAH), or ethylenediamine pyrocatechol (EDP) to etch the Si substrate 10. Alternatively, one or more of SF6, CF4, and Cl2 gases, mixed with N2 and / or O2 gases, can be used to etch the substrate 10 via a dry etching process. In some embodiments, the substrate below the third opening 15 is etched to expose the first capping layer 20. Through such etching operations, the framework structure of the protective film is formed from a portion of the substrate 10 and a portion of the back-side coating 50.

[0080] Next, as Figure 11 As shown, one or more metal layers 100 are formed over the second capping layer 40. In some embodiments, the metal layer 100 comprises a layer of Mo, Zr, Nb, B, Ti, Ru, MoSi, ZrSi, NbSi, or NiZrSi, or other suitable material. In some embodiments, the metal layer 100 includes a Ru layer. In some embodiments, the metal layer 100 includes a Ru layer formed over a Mo layer or a MoSi layer. In other embodiments, a Ru layer formed over a Zr layer is used. In some embodiments, only a Zr layer is formed over the second capping layer 40. In some embodiments, only a Ru layer is formed over the second capping layer 40. In some embodiments, the thickness of the metal layer 100 is in the range of about 0.5 nanometers to about 20 nanometers, and in other embodiments, the thickness of the metal layer 100 is in the range of about 1 nanometer to about 10 nanometers. The metal layer 100 may be formed by chemical vapor deposition, physical vapor deposition, atomic layer deposition, electroplating, and any other suitable film formation method. In some embodiments, any or all of the metal layers are also formed on the inner wall of the third opening 15. In some embodiments, all layers of the protective film are solid and non-porous. In some embodiments, all layers of the protective film are inorganic.

[0081] Figures 12 to 23 The diagram illustrates the sequential manufacturing operations of a protective film for an extreme ultraviolet (EUV) photomask according to an embodiment of this disclosure. It is understood that, as in... Figures 12 to 23 Additional operations are provided before, during, and after the process shown, and some of the operations described below may be replaced or eliminated for other embodiments of the method. The order of operations / processes may be interchangeable. Same or similar Figures 1 to 11 The materials, configurations, dimensions, structures, conditions, and operations described herein may be used in the following embodiments, and some explanations may be omitted. Similarly, the same or similar Figures 12 to 23The materials, configurations, dimensions, structures, conditions, and operations described herein may be used in the above-described embodiments.

[0082] like Figure 12 As shown, a substrate 10, such as a Si wafer, is fabricated. In some embodiments, the thickness of the substrate 10 is in the range of about 500 micrometers to about 1000 micrometers.

[0083] A first cover layer 20 is formed on the substrate 10 as an etch stop layer, such as Figure 13 As shown. The first capping layer 20 functions as an etch stop layer in subsequent substrate etching operations. The first capping layer 20 comprises one or more layers of semiconductor material, such as SiC, SiGe, Ge, or dielectric material, such as silicon oxide, silicon nitride, SiCN, and silicon nitride, or any other suitable material. In some embodiments, SiC is formed on the substrate 10 by epitaxial growth. In other embodiments, the first capping layer 20 may be an amorphous or polycrystalline SiC, SiGe, or Ge layer. In some embodiments, the first capping layer 20 is silicon nitride. In some embodiments, the thickness of the capping layer ranges from about 0.5 nanometers to about 40 nanometers, and in other embodiments, the thickness of the capping layer ranges from about 1 nanometer to about 20 nanometers. The first capping layer 20 may be formed via chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), molecular beam epitaxy (MBE), and any other suitable film formation method.

[0084] After the first capping layer 20 is formed, a matrix layer 30 is formed on top of the first capping layer 20, such as... Figure 3 As shown. In some embodiments, the matrix layer 30 comprises a semiconductor material, such as Si, SiC, SiGe; a metal alloy, such as a silicide (WSi, NiSi, TiSi, CoSi, MoSi, etc.); or a dielectric material, such as a silicon nitride. The semiconductor material may be monocrystalline, polycrystalline, or amorphous. In some embodiments, the matrix layer 30 comprises a MoSi or Si layer. In some embodiments, the thickness of the matrix layer 30 is in the range of about 1 nanometer to about 50 nanometers, and in other embodiments, the thickness of the matrix layer 30 is in the range of about 1 nanometer to about 40 nanometers. The matrix layer 30 may be formed via chemical vapor deposition, physical vapor deposition, atomic layer deposition, and any other suitable film formation method.

[0085] Next, as Figure 15As shown, a stabilizing layer 140 is formed over a substrate layer 30. In some embodiments, the stabilizing layer 140 comprises one or more layers of Nb, Mo, Zr, MoSi, boron, and carbon, and alloys thereof. The carbon layer may be amorphous carbon. The stabilizing layer 140 prevents metal diffusion between the substrate layer 30 and the second capping layer 40. In some embodiments, the thickness of the stabilizing layer 140 ranges from about 0.5 nanometers to about 50 nanometers, and in other embodiments, the thickness of the stabilizing layer 140 ranges from about 2 nanometers to about 5 nanometers. In some embodiments, the stabilizing layer is two layers, such as Nb / Mo (one Nb layer over one Mo layer), Nb / Zr, Mo / MoSi, or Mo / C. In some embodiments, the thickness of each of the two layers ranges from about 0.5 nanometers to about 30 nanometers. The stabilizing layer 140 may be formed via chemical vapor deposition, physical vapor deposition, atomic layer deposition, and any other suitable film formation method.

[0086] Subsequently, a second capping layer 40 is formed above the stabilizing layer 140, such as... Figure 16 As shown. In some embodiments, the second capping layer 40 comprises one or more layers of silicon nitride and SiC. In other embodiments, the second capping layer 40 is formed by implanting impurities in the Si core layer. The impurities may be boron, phosphorus, and / or arsenic. In some embodiments, the thickness of the second capping layer 40 is in the range of about 0.5 nanometers to about 10 nanometers, and in other embodiments, the thickness of the second capping layer 40 is in the range of about 1 nanometer to about 5 nanometers. The second capping layer 40 may be formed via chemical vapor deposition, physical vapor deposition, atomic layer deposition, and any other suitable film formation method.

[0087] Next, as Figure 17 As shown, a back-side coating 50 is formed over the back side of the substrate 10. The back-side coating 50 comprises one or more layers of a dielectric material, such as silicon oxide, silicon nitride, silicon nitride, and SiCN. In other embodiments, a metal layer is used. In some embodiments, the thickness of the back-side coating 50 ranges from about 100 nanometers to about 1000 nanometers, and in other embodiments, the thickness of the back-side coating 50 ranges from about 200 nanometers to about 500 nanometers. The back-side coating 50 can be formed via chemical vapor deposition, physical vapor deposition, atomic layer deposition, and any other suitable film formation method.

[0088] After that, as Figure 18 As shown, a photoresist layer 60 is formed on the back-side coating 50. In some embodiments, the thickness of the photoresist layer 60 is in the range of about 1 micrometer to about 3 micrometers. One or more photolithography operations are performed to pattern the photoresist layer 60 to form the first opening 65, such as... Figure 19 As shown.

[0089] Subsequently, the back-side coating 50 is etched using a patterned photoresist layer 60 as an etching mask to form the second opening 55, as shown. Figure 20 As shown. Etching is one or more of dry etching and wet etching operations. The photoresist layer 60 is removed via a suitable photoresist removal operation, as shown. Figure 21 As shown.

[0090] Next, the substrate 10 is etched to form the third opening 15, as shown. Figure 22 As shown. In some embodiments, wet etching is performed using KOH, tetramethylammonium hydroxide (TMAN), or ethylenediamine pyrocatechol (EDP) to etch the Si substrate 10. Alternatively, one or more of SF6, CF4, and Cl2 gases, mixed with N2 and / or O2 gases, can be used to etch the substrate 10 via a dry etching process. In some embodiments, the substrate below the third opening 15 is etched to expose the first capping layer 20. Through this operation, the framework structure of the protective film is formed from a portion of the substrate 10 and a portion of the back-side coating 50.

[0091] Next, as Figure 23 As shown, one or more metal layers 100 are formed over the second capping layer 40. In some embodiments, the metal layer 100 comprises a layer of Mo, Zr, Nb, B, Ti, Ru, MoSi, ZrSi, NbSi, or NiZrSi, or other suitable material. In some embodiments, the metal layer 100 includes a Ru layer. In some embodiments, the metal layer 100 includes a Ru layer formed over a Mo layer or a MoSi layer. In other embodiments, a Ru layer formed over a Zr layer is used. In some embodiments, only a Zr layer is used as the metal layer 100. In some embodiments, only a Ru layer is used as the metal layer 100. In some embodiments, the thickness of the metal layer 100 is in the range of about 0.5 nanometers to about 20 nanometers, and in other embodiments, the thickness of the metal layer 100 is in the range of about 1 nanometer to about 10 nanometers. The metal layer 100 can be formed by chemical vapor deposition, physical vapor deposition, atomic layer deposition, electroplating, and any other suitable film formation method. In some embodiments, any or all metal layers are formed on the inner wall of the third opening 15. In some embodiments, all layers of the protective film are solid and non-porous. In some embodiments, all layers of the protective film are inorganic.

[0092] Figures 24 to 35The diagram illustrates the sequential manufacturing operations of a protective film for an extreme ultraviolet (EUV) photomask according to an embodiment of this disclosure. It is understood that, as in... Figures 24 to 35 Additional operations are provided before, during, and after the process shown, and some of the operations described below may be replaced or eliminated for other embodiments of the method. The order of operations / processes may be interchangeable. Same or similar Figures 1 to 23 The materials, configurations, dimensions, structures, conditions, and operations described herein may be used in the following implementations, and some explanations may be omitted.

[0093] A substrate 10, such as a Si wafer, is fabricated. In some embodiments, the thickness of the substrate 10 is in the range of about 500 micrometers to about 1000 micrometers. A first capping layer 20 is formed on the substrate 10 as an etch stop layer, such as... Figure 24 As shown. In subsequent substrate etching operations, the first capping layer 20 functions as an etch stop layer. The first capping layer 20 comprises one or more layers of semiconductor material, such as SiC, SiGe, Ge; or dielectric material, such as silicon oxide, SiCN, silicon nitride, and silicon nitride; or any other suitable material. In some embodiments, SiC is formed on the substrate 10 by epitaxial growth. In other embodiments, the first capping layer 20 may be an amorphous or polycrystalline SiC, SiGe, or Ge layer. In some embodiments, the first capping layer 20 is silicon nitride. In some embodiments, the thickness of the capping layer ranges from about 0.5 nanometers to about 40 nanometers, and in other embodiments, the thickness of the capping layer ranges from about 1 nanometer to about 20 nanometers. The first capping layer 20 may be formed via chemical vapor deposition (CVD), physical vapor deposition (PVD), atomic layer deposition (ALD), molecular beam epitaxy (MBE), and any other suitable film formation method.

[0094] Next, as Figure 25 As shown, a base matrix layer 130 is formed over a first capping layer 20. In some embodiments, the base matrix layer 130 comprises a semiconductor material, such as Si, SiC, or SiGe; a metal alloy, such as a silicide (WSi, NiSi, TiSi, CoSi, MoSi, etc.); or a dielectric material, such as a silicon nitride. The semiconductor material may be monocrystalline, polycrystalline, or amorphous. In some embodiments, the base matrix layer 130 comprises a polycrystalline silicon layer or an amorphous silicon layer. In some embodiments, the thickness of the base matrix layer 130 is in the range of about 10 nanometers to about 50 nanometers, and in other embodiments, the thickness of the base matrix layer 130 is in the range of about 20 nanometers to about 40 nanometers. The base matrix layer 130 may be formed via chemical vapor deposition, physical vapor deposition, atomic layer deposition, molecular beam epitaxy, and any other suitable film formation method.

[0095] Next, as Figure 26 As shown, a base stabilizing layer 150 is formed over a base matrix layer 130. In some embodiments, the base stabilizing layer 150 comprises one or more layers of a metal-based material, such as Mo, Zr, Ru, and Nb, and alloys thereof. In some embodiments, the thickness of the base stabilizing layer 150 ranges from about 1 nanometer to about 20 nanometers. The base stabilizing layer 150 can be formed via chemical vapor deposition, physical vapor deposition, atomic layer deposition, and any other suitable film formation method.

[0096] After that, as Figure 27 As shown, the base matrix layer 130 and the base stabilizing layer 150 are mixed via an annealing process to form an alloy layer 160. In some embodiments, the alloy layer 160 is a silicide layer, such as MoSi, NbSi, ZrSi, RuSi, etc. Compared to directly forming a silicide layer as the matrix layer 30, forming a silicide layer above the substrate can improve surface roughness (a smoother surface) and suppress phase separation, which would otherwise be caused by subsequent high-temperature processes.

[0097] Subsequently, a second cover layer 40 is formed above the alloy layer 160, such as... Figure 28 As shown. In some embodiments, the second capping layer 40 comprises one or more layers of silicon nitride and SiC. In other embodiments, the second capping layer 40 is formed by implanting impurities in the Si core layer. The impurities may be boron, phosphorus, and / or arsenic. In some embodiments, the thickness of the second capping layer 40 is in the range of about 0.5 nanometers to about 10 nanometers, and in other embodiments, the thickness of the second capping layer 40 is in the range of about 1 nanometer to about 5 nanometers. The second capping layer 40 may be formed via chemical vapor deposition, physical vapor deposition, atomic layer deposition, and any other suitable film formation method.

[0098] Next, as Figure 29 As shown, a back-side coating 50 is formed over the back side of the substrate 10. The back-side coating 50 comprises one or more layers of a dielectric material, such as silicon oxide, silicon nitride, silicon nitride, and SiCN. In other embodiments, a metal layer is used. In some embodiments, the thickness of the back-side coating 50 ranges from about 100 nanometers to about 1000 nanometers, and in other embodiments, the thickness of the back-side coating 50 ranges from about 200 nanometers to about 500 nanometers. The back-side coating 50 can be formed via chemical vapor deposition, physical vapor deposition, atomic layer deposition, molecular beam epitaxy, and any other suitable film formation method.

[0099] After that, as Figure 30As shown, a photoresist layer 60 is formed on the back-side coating 50. In some embodiments, the thickness of the photoresist layer 60 is in the range of about 1 micrometer to about 3 micrometers. One or more photolithography operations are performed to pattern the photoresist layer 60 to form the first opening 65, such as... Figure 31 As shown.

[0100] Subsequently, the back-side coating 50 is etched using a patterned photoresist layer 60 as an etching mask to form the second opening 55, as shown. Figure 32 As shown. Etching is one or more of dry etching and wet etching operations. The photoresist layer 60 is removed via a suitable photoresist removal operation, as shown. Figure 33 As shown.

[0101] Next, the substrate 10 is etched to form the third opening 15, as shown. Figure 34 As shown. In some embodiments, wet etching is performed using KOH, tetramethylammonium hydroxide (TMAH), or ethylenediamine pyrocatechol (EDP) to etch the Si substrate 10. Alternatively, one or more of SF6, CF4, and Cl2 gases, mixed with N2 and / or O2 gases, can be used to etch the substrate 10 via a dry etching process. In some embodiments, the substrate below the third opening 15 is etched to expose the first capping layer 20. Through such etching operations, the framework structure of the protective film is formed from a portion of the substrate 10 and a portion of the back-side coating 50.

[0102] Next, as Figure 35As shown, one or more metal layers 100 are formed over the second capping layer 40. In some embodiments, the metal layer 100 comprises a layer of Mo, Zr, Nb, B, Ti, Ru, MoSi, ZrSi, NbSi, or NiZrSi, or other suitable material. In some embodiments, the metal layer 100 includes a Ru layer. In some embodiments, the metal layer 100 includes a Ru layer formed over a Mo layer or a MoSi layer. In other embodiments, a Ru layer formed over a Zr layer is used. In some embodiments, only a Zr layer is used as the metal layer 100. In some embodiments, only a Ru layer is used as the metal layer 100. In some embodiments, the thickness of the metal layer 100 is in the range of about 0.5 nanometers to about 20 nanometers, and in other embodiments, the thickness of the metal layer 100 is in the range of about 1 nanometer to about 10 nanometers. The metal layer 100 can be formed by chemical vapor deposition, physical vapor deposition, atomic layer deposition, electroplating, and any other suitable film formation method. In some embodiments, any or all metal layers are formed on the inner wall of the third opening 15. In some embodiments, all layers of the protective film are solid and non-porous. In some embodiments, all layers of the protective film are inorganic.

[0103] Figure 36 This shows a cross-sectional view of a protective film for an extreme ultraviolet (EUV) photomask according to another embodiment of this disclosure. In this embodiment, the frame structure has a tapered shape, with a larger opening on the back-side coating 50 side than on the side facing the first cover layer 20. In some embodiments, the tapered frame is formed by using an isotropic etching operation. The tapered frame can be applied to any of the embodiments described above.

[0104] Figure 37 Showing a cross-sectional view of a protective film for an extreme ultraviolet (EUV) photomask according to another embodiment of this disclosure. Same or similar. Figures 1 to 36 The materials, configurations, dimensions, structures, conditions, and operations described herein may be used in the following implementations, and some explanations may be omitted.

[0105] In this embodiment, the protective film includes a first substrate layer 170 over a first capping layer 20, a second substrate layer 180 over the first substrate layer 170, and a second capping layer 40 and a metal layer 100 over the second substrate layer 180. In some embodiments, the first substrate layer 170 includes a semiconductor material, such as Si, SiC, and SiGe. The semiconductor material may be monocrystalline, polycrystalline, or amorphous. In some embodiments, the first substrate layer 170 includes a polycrystalline silicon layer or an amorphous silicon layer. In some embodiments, the thickness of the first substrate layer 170 is in the range of about 10 nanometers to about 50 nanometers, and in other embodiments, the thickness of the first substrate layer 170 is in the range of about 20 nanometers to about 40 nanometers. The second substrate layer 180 includes a silicide, such as WSi, NiSi, TiSi, CoSi, MoSi, NbSi, ZrSi, NbZrSi, or the like. In some embodiments, the second substrate layer 180 includes a MoSi layer or a ZrSi layer. In some embodiments, the silicide layer is subjected to nitriding or oxidation to form, for example, MoSiN, ZrSiN, MoSiO, or ZrSiO. In some embodiments, the thickness of the second matrix layer 180 is in the range of about 10 nanometers to about 50 nanometers, and in other embodiments, the thickness of the second matrix layer 180 is in the range of about 20 nanometers to about 40 nanometers.

[0106] Figure 38 A cross-sectional view is shown illustrating a protective film 200 attached to an extreme ultraviolet (EUV) photomask according to an embodiment of this disclosure. The frame structure of the protective film 200 is attached to the surface of the EUV photomask 210 using a suitable bonding material. In some embodiments, the bonding material is an adhesive, such as an acrylic glue, a silicone-based glue, or an A-B cross-link type glue. The dimensions of the frame structure are larger than the area of ​​the black border 212 of the EUV photomask 210, so the protective film 200 covers not only the area of ​​the circuit pattern 214 of the photomask but also the black border 212.

[0107] In some embodiments of this disclosure, a photoresist pattern is formed using an extreme ultraviolet (EUV) photomask having a protective film as described above. The EUV photomask with the protective film is placed in an EUV exposure tool. A substrate (wafer) coated with photoresist is also placed in the EUV exposure tool. EUV light is generated at the EUV light source and guided onto the EUV photomask through the protective film. The EUV light is then reflected by the EUV photomask, and the reflected light carrying circuit pattern information is guided onto the photoresist layer on the substrate. A development operation is then performed to form the photoresist pattern. Subsequently, by using the photoresist pattern as an etching mask, the under-layer is patterned through one or more etching operations to create a pattern for a semiconductor device.

[0108] Compared to conventional protective films, the protective film according to the embodiments of this disclosure can provide higher strength and thermal conductivity (dissipation), as well as higher extreme ultraviolet light transmittance and lower extreme ultraviolet light reflectance.

[0109] It will be understood that not all advantages need to be discussed herein, not all implementations or embodiments require specific advantages, and other implementations or embodiments may offer different advantages.

[0110] According to one embodiment of this disclosure, a protective film for an extreme ultraviolet (EUV) photomask includes a first capping layer, a substrate layer disposed above the first capping layer, a second capping layer disposed above the substrate layer, and a metal layer disposed above the second capping layer. In one or more of the foregoing and following embodiments, the substrate layer is made of a silicide. In one or more of the foregoing and following embodiments, the silicide is MoSi or ZrSi. In one or more of the foregoing and following embodiments, the first capping layer and the second capping layer are made of one or more of silicon oxide, silicon nitride, silicon nitride, SiC, and SiCN. In one or more of the foregoing and following embodiments, the first capping layer and the second capping layer are made of the same material. In one or more of the foregoing and following embodiments, the first capping layer and the second capping layer are made of different materials. In one or more of the foregoing and following embodiments, the metal layer is one or more of a Ru layer, a Mo layer, and a Zr layer.

[0111] According to another aspect of this disclosure, a protective film for an extreme ultraviolet (EUV) photomask includes a first capping layer, a matrix layer disposed above the first capping layer, a stabilizing layer disposed above the matrix layer, a second capping layer disposed above the stabilizing layer, and a metal layer disposed above the stabilizing layer. In one or more of the foregoing and following embodiments, the stabilizing layer is one or more of an Nb layer, a boron layer, and a carbon layer. In one or more of the foregoing and following embodiments, the matrix layer is made of a silicide. In one or more of the foregoing and following embodiments, the silicide is one or more of MoSi, ZrSi, and NbSi. In one or more of the foregoing and following embodiments, the first capping layer and the second capping layer are made of one or more of silicon oxide, silicon nitride, silicon nitride, SiC, and SiCN. In one or more of the foregoing and following embodiments, the first capping layer and the second capping layer are made of the same material. In one or more of the foregoing and following embodiments, the first capping layer and the second capping layer are made of different materials. In one or more of the foregoing and following embodiments, the metal layer is one or more of a Ru layer, a Mo layer, and a Zr layer. In one or more of the foregoing and following embodiments, the thickness of the stabilizing layer is in the range of 0.5 nanometers to 10 nanometers. In one or more of the foregoing and following embodiments, the matrix layer is one of a polycrystalline silicon layer and an amorphous silicon layer, and the stabilizing layer is one or more of a MoSi layer, a ZrSi layer, and a NbSi layer.

[0112] According to another aspect of this disclosure, in a method for manufacturing a protective film for an extreme ultraviolet (EUV) photomask, a first cover layer is formed above the front surface of a substrate. A first base matrix layer is formed above the first cover layer. A second base matrix layer is formed above the first base matrix layer. An alloy is formed from the first base matrix layer and the second base matrix layer via a thermal process, serving as an alloy matrix layer. A second cover layer is formed above the alloy matrix layer. A back-side coating is formed above the back surface of the substrate. A first opening is formed in the back-side coating by patterning the back-side coating. The substrate is etched through the first opening to form a second opening in the substrate. One or more metal layers are formed above the second cover layer. In one or more of the foregoing and following embodiments, the first base matrix layer is polycrystalline silicon or amorphous silicon, and the second base matrix layer is one or more of Mo, Zr, and Nb.

[0113] Some embodiments of this disclosure provide a protective film for an extreme ultraviolet (EUV) photomask, comprising: a first cover layer, a substrate layer, a second cover layer, and a metal layer. The substrate layer is disposed above the first cover layer; the second cover layer is disposed above the substrate layer; and the metal layer is disposed above the second cover layer.

[0114] In some embodiments, the matrix layer is made of silicide.

[0115] In some embodiments, the silicide is MoSi or ZrSi.

[0116] In some embodiments, the first and second capping layers are made of one or more of silicon oxide, silicon nitride, silicon nitride oxide, SiC, and SiCN.

[0117] In some embodiments, the first cover layer and the second cover layer are made of the same material.

[0118] In some embodiments, the first cover layer and the second cover layer are made of different materials from each other.

[0119] In some embodiments, the metal layer is one or more of a Ru layer, a Mo layer, and a Zr layer.

[0120] Other embodiments of this disclosure provide a protective film for an extreme ultraviolet (EUV) photomask, comprising: a first cover layer, a substrate layer, a stabilizing layer, a second cover layer, and a metal layer. The substrate layer is disposed above the first cover layer; the stabilizing layer is disposed above the substrate layer; the second cover layer is disposed above the stabilizing layer; and the metal layer is disposed above the stabilizing layer.

[0121] In some embodiments, the stabilizing layer is one or more of an Nb layer, a boron layer, and a carbon layer.

[0122] In some embodiments, the matrix layer is made of silicide.

[0123] In some embodiments, the silicide is one or more of MoSi, ZrSi, and NbSi.

[0124] In some embodiments, the first and second capping layers are made of one or more of silicon oxide, silicon nitride, silicon nitride oxide, SiC, and SiCN.

[0125] In some embodiments, the first cover layer and the second cover layer are made of the same material.

[0126] In some embodiments, the first cover layer and the second cover layer are made of different materials from each other.

[0127] In some embodiments, the metal layer is one or more of a Ru layer, a Mo layer, and a Zr layer.

[0128] In some implementations, the thickness of the stabilizing layer is in the range of 0.5 nanometers to 10 nanometers.

[0129] In some embodiments, the matrix layer is one of a polycrystalline silicon layer and an amorphous silicon layer, and the stabilizing layer is one or more of a MoSi layer, a ZrSi layer, and a NbSi layer.

[0130] Some embodiments of this disclosure provide a method for manufacturing a protective film for an extreme ultraviolet (EUV) photomask, the method comprising: forming a first cover layer above a front surface of a substrate; forming a first base matrix layer above the first cover layer; forming a second base matrix layer above the first base matrix layer; forming an alloy from the first base matrix layer and the second base matrix layer via a thermal operation as an alloy matrix layer; forming a second cover layer above the alloy matrix layer; forming a back-side coating above a back surface of the substrate; forming a first opening in the back-side coating via patterning the back-side coating; forming a second opening in the substrate by etching through the first opening; and forming one or more metal layers above the second cover layer.

[0131] In some embodiments, the first base matrix layer is polycrystalline silicon or amorphous silicon, and the second base matrix layer is one or more of Mo, Zr, and Nb.

[0132] In some implementations, the metal layer is one or more Zr layers.

[0133] Several implementation methods or embodiments have been outlined above to enable those skilled in the art to better understand various aspects of this disclosure. Those skilled in the art should understand that they may readily use this disclosure as a basis for the design and modification of other processes and structures to achieve the same purpose and / or the same advantages as the implementation methods or embodiments described herein. Those skilled in the art should also understand that equivalent constructions do not depart from the spirit and scope of this disclosure, and that various changes, substitutions, and modifications may be made without departing from the spirit and scope of this disclosure.

Claims

1. A protective film for extreme ultraviolet light photomasks, characterized in that, Include: A first capping layer, wherein the first capping layer is made of one or more of silicon oxide, silicon nitride, silicon nitride, SiC, and SiCN; A matrix layer is disposed above the first capping layer, wherein the matrix layer is made of a silicide, and the silicide is one or more of MoSi, ZrSi, and NbSi; A stabilizing layer is disposed above the matrix layer, wherein the stabilizing layer is a double layer consisting of an Nb layer on a Mo layer, an Nb layer on a Zr layer, a Mo layer on a MoSi layer, or a Mo layer on a C layer. A second capping layer is disposed above the stabilizing layer, wherein the second capping layer is made of one or more of silicon oxide, silicon nitride, silicon nitride, SiC, and SiCN; A metal layer is disposed above the stabilizing layer; and A frame structure is disposed around the surface of the first cover layer on the opposite side of the matrix layer, the frame structure comprising: A silicon layer, in direct contact with the first capping layer; and A back-side coating is disposed on a surface of the silicon layer opposite to the first capping layer, the back-side coating comprising one or more layers of dielectric material or metal. The first covering layer is located on the outermost side of the protective film facing an extreme ultraviolet light shield, and the metal layer is located on the outermost side of the protective film away from the extreme ultraviolet light shield.

2. The protective film for extreme ultraviolet light photomasks as described in claim 1, characterized in that, The thickness of the stabilizing layer ranges from 0.5 nanometers to 50 nanometers.

3. The protective film for extreme ultraviolet light photomasks as described in claim 2, characterized in that, The first and second covering layers are made of the same material.

4. The protective film for extreme ultraviolet light photomasks as described in claim 2, characterized in that, The first and second covering layers are made of different materials.

5. The protective film for an extreme ultraviolet light photomask as described in claim 1, characterized in that, The metal layer is one or more of a Ru layer, a Mo layer, and a Zr layer.

6. The protective film for an extreme ultraviolet light photomask as described in claim 1, characterized in that, The thickness of the stabilizing layer is in the range of 0.5 nanometers to 10 nanometers.

7. The protective film for an extreme ultraviolet light photomask as described in claim 1, characterized in that, in: The thickness of each of the two layers in this stabilizing layer ranges from 0.5 nanometers to 30 nanometers.

8. A method for manufacturing a protective film for extreme ultraviolet (EUV) photomasks, characterized in that, The method includes: A first layer is formed above a front surface of a substrate, wherein the first layer is a first capping layer, and the first capping layer is made of one or more of silicon oxide, silicon nitride, silicon oxynitride, SiC, or SiCN; A second layer is formed above the first layer, wherein the second layer is a matrix layer made of a silicide, and the silicide is one or more of MoSi, ZrSi and NbSi; A third layer is formed above the second layer, wherein the third layer is a double layer consisting of an Nb layer on a Mo layer, an Nb layer on a Zr layer, a Mo layer on a MoSi layer, or a Mo layer on a C layer. A fourth layer is formed above the third layer, wherein the fourth layer is a second capping layer, the second capping layer being made of one or more of silicon oxide, silicon nitride, silicon oxynitride, SiC, or SiCN; A back-side opening and a frame structure are formed on one back side of the substrate. The frame structure includes the etched substrate and an etched coating, the coating comprising one or more dielectric material or metal layers; and A fifth layer is formed above the fourth layer. The fifth layer is a metal layer, including one or more of Mo, Zr, Nb, Ti, or Ru; The first covering layer is located on the outermost side of the protective film facing an extreme ultraviolet light shield, and the metal layer is located on the outermost side of the protective film away from the extreme ultraviolet light shield.

9. The method for manufacturing a protective film for an extreme ultraviolet photomask as described in claim 8, characterized in that, The first layer and the fourth layer are made of different materials.

10. The method for manufacturing a protective film for an extreme ultraviolet photomask as described in claim 8, characterized in that, The thickness of the third layer ranges from 0.5 nanometers to 50 nanometers.

11. The method for manufacturing a protective film for an extreme ultraviolet photomask as described in claim 8, characterized in that, The thickness of each of the two layers in the third layer ranges from 0.5 nanometers to 30 nanometers.

Images