Mask blank and manufacturing method thereof, binary mask and manufacturing method thereof

Abstract

The invention provides a mask blank and a manufacturing method thereof, and a binary mask and a manufacturing method thereof. The mask blank comprises a light-transmitting substrate, an etching cut-off film, a shading film and a hard mask which are sequentially stacked, materials of the etching cut-off film comprise metal elements and non-metal elements, and the metal elements are selected from Cr, Ta, Hf, Zr, Al, W or Ni; the shading film is made of a molybdenum-silicon compound and a non-metallic element; the optical density of the etching cut-off film and the shading film under an exposure light source with the wavelength of less than or equal to 250nm is greater than or equal to 3.0, and the surface reflectivity is less than or equal to 40%; the material of the hard mask comprises Cr and non-metallic elements; the non-metallic element is selected from one or more of O, N, C, B and P; the binary mask provided by the invention has the advantages of high resolution, excellent etching resistance and difficulty in excessive etching of the substrate.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor preparation, and in particular to a mask blank and a manufacturing method thereof, a binary mask and a manufacturing method thereof. Background Art

[0002] In the manufacturing process of semiconductor devices, photolithography is usually used to form fine patterns. In the process of pattern miniaturization using photolithography, in addition to miniaturizing the mask pattern of the transfer mask, it is also necessary to reduce the wavelength of the exposure light source as much as possible. In recent years, the exposure light source used in deep ultraviolet (DUV) lithography has been advanced to ArF excimer laser, which has a wavelength of 193nm.

[0003] The mask mainly includes binary mask and binary mask. The binary mask is manufactured by forming a mask pattern on a mask blank through a corresponding photolithography process. The binary mask realizes the transfer of the mask pattern through the contrast between the light-transmitting area and the opaque area. The binary mask mainly includes COG (Chrome on Glass) and OMOG (Opaque MoSi on Glass). Compared with COG, the OMOG film layer is thinner, which can effectively reduce the 3D effect of the mask and is used at a lower technology node. The optical density of the OMOG mask blank shading film is generally greater than or equal to 3.0.

[0004] In order to obtain fine photomask pattern, on the one hand, resist pattern needs to be more miniaturized, so thinner resist film is needed.If the film thickness of resist film is not reduced, the excessively high thickness will cause the aspect ratio of the resist part used as light shielding layer to become larger, thereby causing the pattern shape to be easily deteriorated, and the resolution of the transfer pattern on the light shielding layer using it as etching mask is reduced.Even in extreme cases, a part of the resist pattern collapses or peels off, resulting in the formation of pattern blank.On the other hand, when light shielding film patterning is carried out with resist film as etching mask, common light shielding film (such as light shielding film containing chromium or molybdenum silicon compound) is usually formed into pattern by dry etching, and most etching conditions also have etching effect that cannot be ignored on resist film.If light shielding film is etched with thinner resist film as mask, too thin resist film is not enough to block the long-term attack of plasma, causing resist film to be damaged in etching process, and then causing the resist pattern shape to change, it is difficult to accurately transfer the original resist pattern to the light shielding film.

[0005] Based on the existing pattern forming process, in order to obtain high resolution, the resist film needs to be thinned, and in order to ensure that the resist film has good etching resistance in the pattern forming process, its thickness needs to be increased. On this basis, the existing organic resist film is difficult to meet both high resolution and excellent etching resistance.

[0006] Moreover, for the mask blank composed of the resist film, hard mask, shading film and translucent substrate, when the hard mask is used as a mask and the light-shielding film is dry-etched, the translucent substrate is easily over-etched and etched unevenly, which leads to uneven optical performance in the subsequent pattern transfer process.

[0007] Therefore, in order to form a higher resolution photomask pattern, realize thin filmization of the resist film, improve its etching resistance, and reduce over-etching of the substrate, it is urgently necessary to provide a mask blank and a manufacturing method thereof, a binary mask and a manufacturing method thereof. Summary of the invention

[0008] The main purpose of the present invention is to provide a mask blank and a manufacturing method thereof, a binary mask and a manufacturing method thereof, so as to solve the problem that the binary mask in the prior art is difficult to simultaneously meet the requirements of high resolution and excellent etching resistance, and there is also the problem that the substrate is prone to over-etching.

[0009] In order to achieve the above-mentioned purpose, the present invention provides a mask blank on the one hand, which includes a translucent substrate, an etching stop film, a shading film and a hard mask which are stacked in sequence, wherein the material of the etching stop film includes metal elements and non-metal elements, and the metal elements are selected from Cr, Ta, Hf, Zr, Al, W or Ni; the material of the shading film includes molybdenum silicon compounds and non-metal elements; the optical density of the etching stop film and the shading film under an exposure light source with a wavelength of ≤250nm is ≥3.0, and the surface reflectivity is ≤40%; the material of the hard mask includes Cr and non-metal elements; the non-metal elements are selected from one or more of O, N, C, B and P.

[0010] Furthermore, the etching stop film is a single-layer or multi-layer structure with a thickness of 1-10 nm. In each layer of the etching stop film, the atomic percentage of Cr is ≥30 at.%, the atomic percentage of C is ≤15 at.%, and the remainder is other elements.

[0011] Furthermore, the shading film has a double-layer structure with a thickness of 40 to 70 nm, the film layer close to the etching stop film is the shading layer, and the film layer away from the etching stop film is the anti-reflection layer, wherein the atomic percentage of Mo in the shading layer is ≥8at.%, the atomic percentage of Si is ≥45at.%, the atomic percentage of N is ≤37at.%, and the atomic percentage of O is ≤10at.%; the atomic percentage of Mo in the anti-reflection layer is ≤10at.%, the atomic percentage of Si is ≥40at.%, the atomic percentage of N is ≥25at.%, and the atomic percentage of O is ≤25at.%; the thickness of the shading layer is 38 to 60 nm, and the thickness of the anti-reflection layer is 2 to 20 nm.

[0012] Furthermore, the light-shielding film has a three-layer structure with a thickness of 40 to 70 nm, and includes a first light-shielding layer, a second light-shielding layer and an anti-reflection layer in sequence. The first light-shielding layer is arranged on a surface close to the etching stop film, the anti-reflection layer is arranged on a surface close to the hard mask, and the atomic percentage of N in the second light-shielding layer is lower than the atomic percentage of N in the first light-shielding layer; wherein, the atomic percentage of Mo in the first light-shielding layer and the second light-shielding layer is ≥10at.%, the atomic percentage of Si is ≥45at.%, the atomic percentage of N is ≤30at.%, and the atomic percentage of O is ≤5at.%; the atomic percentage of Mo in the anti-reflection layer is ≤10at.%, the atomic percentage of Si is ≥40at.%, the atomic percentage of N is ≥25at.%, and the atomic percentage of O is ≤25at.%; the sum of the thicknesses of the first light-shielding layer and the second light-shielding layer is 38 to 60 nm, and the thickness of the anti-reflection layer is 2 to 20 nm.

[0013] Furthermore, the hard mask is a single-layer structure or a multi-layer structure, and has a thickness of 2 to 10 nm.

[0014] Furthermore, the hard mask has a single-layer structure, and the atomic percentage of Cr in the hard mask is ≥50at.%; or, the hard mask has a double-layer structure, wherein the atomic percentage of Cr in the film layer close to the shading film is higher than the atomic percentage of Cr in the film layer away from the shading film; or, the hard mask has a three-layer structure, wherein the atomic percentage of Cr in the middle layer is higher than the atomic percentage of Cr in the other two adjacent layers, and the atomic percentage of Cr in the middle layer is ≥50at.%.

[0015] Furthermore, the mask blank further comprises a resist film, and the resist film is arranged on a surface of the hard mask away from the light-transmitting substrate; the thickness of the resist film is 60-200 nm.

[0016] In order to achieve the above-mentioned purpose, another aspect of the present invention also provides a method for manufacturing a mask blank, which comprises: depositing an etching stop film, a light-shielding film and a hard mask film in sequence on a surface of one side of a light-transmitting substrate to obtain a mask blank; wherein the etching stop film, the light-shielding film and the hard mask film have the same definitions as in the previous text.

[0017] Furthermore, magnetron sputtering is used for deposition, and during the deposition of the etching cut-off film, the shading film and the hard mask, the working pressure is independently 0.1 to 0.4 Pa, the sputtering power is independently 200 to 3500 W, and the working gas is independently one or more of Ar, He, Xe, O2, N2, N2O, NO, NO2, CO2, CO, and CH4.

[0018] Another aspect of the present invention provides a method for manufacturing a binary mask, using the above-mentioned mask blank provided in the present application as a raw material to manufacture a binary mask, the manufacturing method comprising:

[0019] Step S1, coating a resist on a surface of a hard mask in a mask blank away from a light-transmitting substrate to form a resist film, and sequentially performing exposure, baking and development to obtain a first stacked structure containing a patterned resist film;

[0020] Step S2, using the patterned resist film in the first stacked structure as a mask, etching the hard mask in the first stacked structure, and obtaining a second stacked structure including the patterned hard mask after cleaning and removing the patterned resist film;

[0021] Step S3, using the patterned hard mask film in the second stacked structure as a mask, etching the light shielding film in the second stacked structure to obtain a third stacked structure including the patterned light shielding film;

[0022] In step S4, the etch stop film in the third stacked structure is etched using the patterned shading film in the third stacked structure as a mask. During the etching process in step S4, the patterned hard mask is removed, and a binary mask containing the patterned etch stop film is obtained after cleaning.

[0023] Another aspect of the present invention provides a binary mask, which is manufactured using the manufacturing method of the binary mask provided in the present application.

[0024] By applying the technical solution of the present invention, a hard mask is provided on the surface of the mask blank on the side of the light shielding film away from the light-transmitting substrate. Since the hard mask is thin, the loss of the resist film provided on one side of the hard mask is reduced when etching the hard mask in the process of manufacturing the binary mask, and the thickness of the resist film can be reduced to achieve the effect of high resolution and small line width.

[0025] In addition, since the etching time required for hard mask patterning is shorter than that required for light shielding film patterning, the provision of the hard mask can alleviate the load effect occurring during pattern formation and improve CD (critical dimension) linearity.

[0026] Compared with the mask blank without an etching stop film, the mask blank provided in the present application has an etching stop film on the surface of the transparent substrate, which can avoid excessive etching of the transparent substrate and improve the uniformity of optical performance in the subsequent pattern transfer process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0028] Figure 1 A schematic cross-sectional structure diagram of a mask blank provided in the present application is shown;

[0029] Figure 2 A schematic cross-sectional structure diagram of a mask blank in one embodiment of the present application is shown;

[0030] Figure 3 shows a schematic cross-sectional structure diagram of a first stacked structure;

[0031] Figure 4 shows a schematic cross-sectional structure diagram of a second stacked structure;

[0032] Figure 5 shows a schematic cross-sectional structure diagram of a third laminated structure;

[0033] Figure 6 A schematic cross-sectional structure diagram of a binary mask is shown;

[0034] Figure 7 A schematic cross-sectional structure diagram of the mask blank provided in Comparative Example 1 is shown.

[0035] The above drawings include the following reference numerals:

[0036] 10. Transparent substrate; 20. Etching stop film; 21. Patterned etching stop film; 30. Light shielding film; 31. Patterned light shielding film; 40. Hard mask; 41. Patterned hard mask; 50. Resist film; 51. Patterned resist film. DETAILED DESCRIPTION

[0037] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0038] As described in the background art, the existing binary mask has the problem that it is difficult to simultaneously meet the requirements of high resolution and excellent etching resistance, and the substrate is prone to over-etching. In order to solve the above technical problems, the first aspect of the present application provides a mask blank, Figure 1 The cross-sectional structure schematic diagram of the mask blank is shown. The mask blank includes a light-transmitting substrate 10, an etching stop film 20, a light-shielding film 30 and a hard mask film 40 which are stacked in sequence.

[0039] Among them, the material of the etching stop film 20 includes metal elements and non-metal elements, and the metal elements are selected from Cr, Ta, Hf, Zr, Al, W or Ni; the material of the shading film 30 includes molybdenum silicon compound and non-metal elements; the optical density of the etching stop film 20 and the shading film 30 under the exposure light source with a wavelength of ≤250nm is ≥3.0, and the surface reflectivity is ≤40%; the material of the hard mask 40 includes Cr and non-metal elements; the above non-metal elements are each independently selected from one or more of O, N, C, B and P.

[0040] The mask blank provided in the present application is provided with an etching stop film 20, which can prevent excessive etching of the light-transmitting substrate 10 and improve the uniformity of optical performance during the subsequent pattern transfer process, compared with the mask blank without the etching stop film 20. Compared with other types, the use of the above-mentioned type of etching stop film 20 material, and the use of a material different from the type of light-shielding film 30 and the light-transmitting substrate 10, can effectively prevent excessive etching of the light-transmitting substrate 10 and improve the uniformity of optical performance during the pattern transfer process.

[0041] When the mask blank provided by the present application is used in the manufacturing process of a binary mask, due to the setting of the hard mask 40 in the present application, the loss of the resist film 50 can be reduced, and the thickness of the resist film 50 can be reduced, thereby achieving the effect of high resolution and small line width. Compared with other types, the use of the hard mask 40 of the above type is conducive to reducing the thickness of the resist film and reducing the loss of the resist film during the patterning process.

[0042] In a preferred embodiment, the etching stop film 20 is a single-layer or multi-layer structure with a thickness of 1 to 10 nm. The atomic percentage of Cr in each layer of the etching stop film 20 is ≥30 at.%, the atomic percentage of C is ≤15 at.%, and the remainder is other elements.

[0043] In a preferred embodiment, the shading film 30 is a double-layer structure with a thickness of 40 to 70 nm. The film layer close to the etching stop film 20 is a shading layer, and the film layer away from the etching stop film 20 is an anti-reflection layer. The atomic percentage of Mo in the shading layer is ≥8at.%, the atomic percentage of Si is ≥45at.%, the atomic percentage of N is ≤37at.%, and the atomic percentage of O is ≤10at.%; the atomic percentage of Mo in the anti-reflection layer is ≤10at.%, the atomic percentage of Si is ≥40at.%, the atomic percentage of N is ≥25at.%, and the atomic percentage of O is ≤25at.%.

[0044] In a more preferred embodiment, the thickness of the light shielding layer is 38 to 60 nm, and the thickness of the anti-reflection layer is 2 to 20 nm.

[0045] In a preferred embodiment, the shading film 30 is a three-layer structure with a thickness of 40 to 70 nm, and includes a first shading layer, a second shading layer and an anti-reflection layer in sequence. The first shading layer is arranged on a side surface close to the etching stop film 20, and the anti-reflection layer is arranged on a side surface close to the hard mask 40, and the atomic percentage of N in the second shading layer is lower than the atomic percentage of N in the first shading layer; wherein, the atomic percentage of Mo in the first shading layer and the second shading layer is ≥10at.%, the atomic percentage of Si is ≥45at.%, the atomic percentage of N is ≤30at.%, and the atomic percentage of O is ≤5at.%; the atomic percentage of Mo in the anti-reflection layer is ≤10at.%, the atomic percentage of Si is ≥40at.%, the atomic percentage of N is ≥25at.%, and the atomic percentage of O is ≤25at.%.

[0046] In a more preferred embodiment, the sum of the thicknesses of the first light-shielding layer and the second light-shielding layer is 38 to 60 nm, and the thickness of the anti-reflection layer is 2 to 20 nm.

[0047] In order to reduce the thickness of the resist film 50, in a preferred embodiment, the hard mask film 40 is a single-layer structure or a multi-layer structure with a thickness of 2-10 nm.

[0048] In a preferred embodiment, the hard mask 40 is a single-layer structure, wherein the atomic percentage of Cr is ≥50 at.%; or, the hard mask 40 is a double-layer structure, wherein the atomic percentage of Cr in the film layer close to the light shielding film 30 is higher than the atomic percentage of Cr in the film layer away from the light shielding film 30; or, the hard mask 40 is a three-layer structure, wherein the atomic percentage of Cr in the middle layer is higher than the atomic percentage of Cr in the other two adjacent layers, and the atomic percentage of Cr in the middle layer is ≥50 at.%. Compared with other ranges, limiting the Cr content in the hard mask 40 to the above range is conducive to improving the resistance and chlorine-based gas etching resistance of the hard mask 40, and at the same time making it have a better chlorine-based etching rate.

[0049] In a preferred embodiment, Figure 2 As shown, the mask blank further includes a resist film 50, which is disposed on a surface of the hard mask 40 that is away from the light-transmitting substrate 10. The provision of the resist film 50 facilitates exposure processing and subsequent manufacture of a binary mask.

[0050] In a preferred embodiment, the thickness of the resist film 50 is 60-200 nm.

[0051] It should be noted that the thickness of each of the above-mentioned film layers in the present application can be measured by XRR (X-ray reflectivity); the chemical composition of the film layer can be measured by XPS (X-ray photoelectron spectroscopy).

[0052] In order to improve the resolution of the pattern formed by etching, in a preferred embodiment, the material of the resist film 50 is chemically amplified resist.

[0053] The second aspect of the present application also provides a method for manufacturing a mask blank, which comprises: depositing an etching stop film 20, a light shielding film 30 and a hard mask 40 in sequence on a surface of one side of a light-transmitting substrate 10 to obtain a mask blank; wherein the etching stop film 20, the light shielding film 30 and the hard mask 40 have the same definitions as in the previous text.

[0054] The etching stop film 20, the light shielding film 30 and the hard mask film 40 are sequentially prepared on one side surface of the light-transmitting substrate 10 by a deposition method, so as to obtain the mask blank of the above-mentioned laminated structure of the present application.

[0055] In a preferred embodiment, magnetron sputtering is used for deposition. Compared with other methods, magnetron sputtering is advantageous for controlling the deposition effect, thereby improving the performance of each film layer and further improving the resolution of the binary mask.

[0056] In a preferred embodiment, during the deposition of the etching stop film 20, the shading film 30 and the hard mask 40, the working pressure is independently 0.1-0.4 Pa, the sputtering power is independently 200-3500 W, and the working gas is independently one or more of Ar, He, Xe, O2, N2, N2O, NO, NO2, CO2, CO, and CH4.

[0057] The third aspect of the present application also provides a method for manufacturing a binary mask, using the above-mentioned mask blank provided in the present application as a raw material to manufacture a binary mask, the manufacturing method comprising:

[0058] Step S1, coating a resist on the surface of the hard mask 40 in the mask blank away from the light-transmitting substrate 10 to form a resist film 50, and sequentially performing exposure, baking and development to obtain a first stacked structure (such as Figure 3 shown);

[0059] Step S2, using the patterned resist film 51 in the first stacked structure as a mask, etching the hard mask film 40 in the first stacked structure, and after cleaning and removing the patterned resist film 51, obtaining a second stacked structure (such as Figure 4 shown);

[0060] Step S3, using the patterned hard mask 41 in the second stacked structure as a mask, etching the light shielding film 30 in the second stacked structure to obtain a third stacked structure (such as Figure 5 shown);

[0061] Step S4, using the patterned light shielding film 31 in the third stacked structure as a mask, etching the etching stop film 20 in the third stacked structure, the patterned hard mask 41 is removed during the etching process in step S4, and a binary mask (such as etch stop film 21) containing the patterned etching stop film 21 is obtained after cleaning. Figure 6 shown).

[0062] In a preferred embodiment, the etching is preferably dry etching.

[0063] In a preferred embodiment, in step S2, a mixed gas of Cl2 and O2 with a gas flow ratio of 10:1 is used to dry-etch the hard mask 40 in the first stacked structure; in step S3, a mixed gas of SF6 and He with a gas flow ratio of 1:(15-20) is used to dry-etch the shading film 30 in the second stacked structure; in step S4, a mixed gas of Cl2 and O2 with a gas flow ratio of 7:2 is used to dry-etch the etching stop film 20 in the third stacked structure.

[0064] By using the mask blank of the specific stacked structure and material provided in the present application as a raw material and adopting the above-mentioned manufacturing method for manufacturing, a binary mask with high resolution and excellent etching performance can be obtained.

[0065] The fourth aspect of the present application also provides a binary mask, which is manufactured using the manufacturing method of the binary mask provided in the present application. By using the mask blank of the specific laminated structure and material provided in the present application as a raw material and manufacturing it using the manufacturing method, a binary mask with high resolution and excellent etching performance can be obtained.

[0066] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0067] Example 1

[0068] A method for manufacturing a mask blank, comprising:

[0069] (1) preparing a transparent substrate 10 of quartz glass with a size of 152 mm×152 mm×6.35 mm as a mask blank and cleaning the substrate 10, wherein the surface root mean square roughness Rq of the transparent substrate 10 is less than 0.5 nm;

[0070] (2) Preparation of etching stop film 20:

[0071] Direct current (DC) reactive magnetron sputtering was performed on one side surface of the light-transmitting substrate 10, the target material was a chromium (Cr) target, a mixed gas of Ar, O2, and N2 was used as the working gas (wherein the gas flow ratio of Ar, O2, and N2 was 60:1:20), the working gas pressure was set to 0.13 Pa, the power of the DC power supply was 600 W, and a CrON single-layer film with a thickness of 3 nm was obtained. The element contents in the CrON single-layer film were tested to be: the atomic percentage of Cr was 55 at.%, the atomic percentage of O was 8 at.%, and the atomic percentage of N was 37 at.%;

[0072] (3) Preparation of light shielding film 30:

[0073] Three layers are sequentially deposited on the surface of the etching stop film 20 away from the transparent substrate 10 to obtain a light shielding film 30 with a three-layer structure; wherein the film layers close to the etching stop film 20 are the first light shielding layer and the second light shielding layer, respectively, and the film layer away from the etching stop film 20 is an anti-reflection layer;

[0074] The first light shielding layer is deposited by direct current reactive magnetron sputtering, the target material is a molybdenum silicon (MoSi) alloy target, a mixed gas of Ar and N2 is used as the working gas (wherein the gas flow ratio of Ar to N2 is 10:3), the working gas pressure is set to 0.15 Pa, the power of the DC power supply is 500 W, and a MoSiN film layer with a thickness of 4 nm is obtained;

[0075] The optical properties of the first light-shielding layer were measured by an optical ellipsometer, and the results showed that its refractive index n at 193nm was 1.98, and its extinction coefficient k was 2.34; the chemical composition of the first light-shielding layer was measured by XPS, and the atomic percentage of each element in the first light-shielding layer was tested to be: Mo = 16.3at.%, Si = 63.1at.%, N = 20.6at.%; the above element contents were all within the atomic percentage limit range of the first light-shielding layer (Mo atomic percentage ≥ 10at.%, Si atomic percentage ≥ 45at.%, N atomic percentage ≤ 30at.%);

[0076] The second light shielding layer is deposited by direct current reactive magnetron sputtering, the target material is a molybdenum silicon (MoSi) alloy target, a mixed gas of Ar and N2 is used as the working gas (wherein the gas flow ratio of Ar to N2 is 4:1), the working gas pressure is set to 0.15 Pa, the power of the DC power supply is 500 W, and a MoSiN film layer with a thickness of 39 nm is obtained;

[0077] The optical properties of the second light-shielding layer were measured by an optical ellipsometer, and the results showed that its refractive index n at 193nm was 1.84, and its extinction coefficient k was 2.46; the chemical composition of the second light-shielding layer was measured by XPS, and the atomic percentage of each element in the second light-shielding layer was as follows: Mo=18.0at.%, Si=65.6at.%, N=16.4at.%; the contents of the above elements were all within the atomic percentage limit of the second light-shielding layer (Mo atomic percentage ≥10at.%, Si atomic percentage ≥45at.%, N atomic percentage ≤30at.%);

[0078] The anti-reflection layer was deposited by direct current reactive magnetron sputtering, the target material was a molybdenum silicon (MoSi) alloy target, the Si / Mo atomic ratio in the MoSi alloy target used in the deposition process of the anti-reflection layer was greater than that in the MoSi alloy target used in the deposition process of the first light shielding layer, a mixed gas of Ar and N2 was used as the working gas (wherein the gas flow ratio of Ar to N2 was 20:7), the working gas pressure was set to 0.15 Pa, the power of the DC power supply was 400 W, and a MoSiN film layer with a thickness of 4 nm was obtained;

[0079] The optical properties of the layer were measured by an optical ellipsometer, and the results showed that its refractive index n at 193nm was 2.30, and the extinction coefficient k was 1.14. The chemical composition of the anti-reflection layer was measured by XPS, and the atomic percentage of each element in the anti-reflection layer was: Mo = 7.7at.%, Si = 56.0at.%, N = 36.2at.%; the contents of the above elements were all within the atomic percentage limit of the anti-reflection layer (Mo atomic percentage ≤ 10at.%, Si atomic percentage ≥ 40at.%, N atomic percentage ≥ 25at.%);

[0080] The optical performance of the light shielding film 30 was simulated based on the above-mentioned related measured parameters. The results showed that the optical density of the light shielding film 30 was 3.1 under the 193nm wavelength light, the total optical density of the etching cut-off film 20 and the light shielding film 30 was 3.2, and the reflectivity was 34.6%;

[0081] (4) Preparation of hard mask 40:

[0082] Direct current reactive magnetron sputtering is performed on the surface of the light shielding film 30 away from the light-transmitting substrate 10 to obtain a hard mask film 40 having a three-layer structure; wherein the film layers close to the light shielding film 30 are the first hard mask layer and the second hard mask layer in sequence, and the film layer away from the light shielding film 30 is the third hard mask layer;

[0083] The first hard mask layer is deposited by direct current reactive magnetron sputtering, the target material is a Cr target, a mixed gas of Ar, O2 and N2 is used as the working gas (wherein the gas flow ratio of Ar, O2 and N2 is 10:1:2), the working gas pressure is set to 0.1 Pa, the power of the DC power supply is 200 W, and a CrON film layer with a thickness of 1 nm is obtained, wherein the chemical composition of the layer of the hard mask 40 close to the light shielding film 30 is measured by XPS, and the atomic percentage of each element is tested to be: Cr = 50at.%, O = 35at.%, N = 15at.%;

[0084] The second hard mask layer is deposited by direct current reactive magnetron sputtering, the target material is a Cr target, a mixed gas of Ar and N2 is used as the working gas (wherein the gas flow ratio of Ar and N2 is 15:1, and the pressure is 0.35Pa), the working gas pressure is set to 0.35Pa, the power of the DC power supply is 500W, and a CrN film layer with a thickness of 2nm is obtained, wherein the chemical composition of the intermediate layer of the hard mask 40 is measured by XPS, and the atomic percentage content of each element is tested to be: Cr = 90at.%, N = 10at.%;

[0085] The third hard mask layer is deposited by DC reactive magnetron sputtering, the target material is a Cr target, a mixed gas of Ar, O2 and N2 is used as the working gas (wherein the gas flow ratio of Ar, O2 and N2 is 10:1:2), the working gas pressure is set to 0.1 Pa, the power of the DC power supply is 200 W, and a CrON film layer with a thickness of 1 nm is obtained. The chemical composition of the layer of the hard mask 40 away from the side of the shading film 30 is measured by XPS, and the test results show that the atomic percentage of each element is: Cr = 50at.%, O = 35at.%, N = 15at.%.

[0086] The cross-sectional structure diagram of the mask blank prepared in Example 1 is as follows Figure 1 shown.

[0087] A method for manufacturing a binary mask, using the mask blank prepared in Example 1, comprises:

[0088] (1) A layer of a chemically amplified resist film 50 with a thickness of 100 nm and sensitive to electron beams is spin-coated on the surface of the hard mask film 40 of the mask blank away from the light-transmitting substrate 10; then, an electron beam exposure machine is used to expose the hard mask film 40, and the wavelength of the exposure light source is 193 nm. After baking and developing, a first stacked structure containing a patterned resist film 51 is obtained, which serves as a mask in the subsequent etching process; (e.g. Figure 3 shown);

[0089] (2) Using the patterned resist film 51 in the first stacked structure as a mask, a mixed gas of Cl2 and O2 with a gas flow ratio of 10:1 is used to dry-etch the hard mask film 40 in the first stacked structure, and the patterned resist film 51 is removed by wet cleaning to obtain a second stacked structure containing the patterned hard mask 41 (e.g. Figure 4 shown);

[0090] (3) Using the patterned hard mask 41 in the second stacked structure as a mask, a mixed gas of SF6 and He with a gas flow ratio of 1:15 is used to dry-etch the light shielding film 30 in the second stacked structure to obtain a third stacked structure (such as Figure 5 shown);

[0091] (4) Using the patterned light shielding film 31 in the third stacked structure as a mask, a mixed gas of Cl2 and O2 with a gas flow ratio of 7:2 is used to dry-etch the etching stop film 20 in the third stacked structure. During the etching process, the patterned hard mask 41 is removed. After wet cleaning, a binary mask (such as FIG. 4 ) containing the patterned etching stop film 21 is obtained. Figure 6 shown);

[0092] Since the light shielding film 30 , the hard mask film 40 and the etching stop film 20 all have a large etching selectivity ratio, the light shielding performance of the light shielding film 30 will not be affected by the etching during the dry etching process.

[0093] Comparative Example 1

[0094] The difference from Example 1 is that in the process of preparing the mask blank, in the process of preparing the light-shielding film 30 in step (3), the preparation process of the first light-shielding layer and the anti-reflection layer is the same as that in Example 1, and the preparation process of the second light-shielding layer is different from that in Example 1, specifically, including:

[0095] The second light-shielding layer is deposited by direct current reactive magnetron sputtering, the target material is a molybdenum silicon (MoSi) alloy target, a mixed gas of Ar and N2 is used as the working gas (wherein the gas flow ratio of Ar to N2 is 2:1, which is different from Example 1), the working gas pressure is set to 0.15 Pa, the power of the DC power supply is 500 W, and a MoSiN film layer with a thickness of 39 nm is obtained; the chemical composition of the second light-shielding layer is determined by XPS, and the atomic percentage of each element in the second light-shielding layer is tested to be: Mo = 12.0 at.%, Si = 52.8 at.%, N = 35.2 at.%; the N element content of the above comparative example 1 is not within the atomic percentage limit range of the second light-shielding layer of the present application (Mo atomic percentage ≥ 10 at.%, Si atomic percentage ≥ 45 at.%, N atomic percentage ≤ 30 at.%);

[0096] The optical performance of the light shielding film 30 was simulated based on the above-mentioned related measured parameters. The results show that the optical density of the light shielding film 30 is 2.8 under 193nm wavelength light, and the total optical density of the etching cut-off film 20 and the light shielding film 30 is 2.9, which does not meet the requirement of optical density ≥ 3.0, and the surface reflectivity is 31.0%.

[0097] Comparative Example 2

[0098] The difference from Example 1 is that the prepared mask blank does not contain the etching stop film 20 (such as Figure 7 As shown in FIG. 1 , the process of preparing a binary mask using the mask blank comprises the following steps:

[0099] (1) A layer of a chemically amplified resist film 50 with a thickness of 100 nm and sensitive to electron beams is spin-coated on the surface of the hard mask film 40 of the mask blank of comparative example 2 which is away from the light-transmitting substrate 10; then, an electron beam exposure machine is used to expose the hard mask film 40, and the wavelength of the exposure light source is 193 nm. After baking and developing, a fourth stacked structure containing a patterned resist film 51 is obtained, which is used as a mask in the subsequent etching process;

[0100] (2) using the patterned resist film 51 in the fourth stacked structure as a mask, dry etching the hard mask film 40 in the fourth stacked structure using a mixed gas of Cl2 and O2 with a gas flow ratio of 10:1, and wet cleaning the patterned resist film to obtain a fifth stacked structure including the patterned hard mask film 41, wherein the cleaning agent is a combination of SPM (containing H2SO4, H2O2 and H2O), SC1 (containing NH4OH, H2O2 and H2O) and deionized water;

[0101] (3) using the patterned hard mask film 40 in the fifth stacked structure as a mask, dry etching the light shielding film 30 in the fifth stacked structure using a mixed gas of SF6 and He with a gas flow ratio of 1:15 to obtain a sixth stacked structure including the patterned light shielding film 30;

[0102] (4) The hard mask 40 in the sixth stacked structure is dry-etched using a mixed gas of Cl 2 and O 2 with a gas flow ratio of 10:1. After the etching is completed, the binary mask of Comparative Example 2 is obtained after wet cleaning.

[0103] It was observed that the transparent substrate 10 of the binary mask in Comparative Example 2 was over-etched and uneven, resulting in uneven optical properties during the subsequent pattern transfer process.

[0104] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects:

[0105] The mask blank provided in the present application is provided with an etching stop film 20, which can prevent excessive etching of the light-transmitting substrate 10 and improve the uniformity of optical performance during the subsequent pattern transfer process, compared with the mask blank without the etching stop film 20. Compared with other types, the use of the above-mentioned type of etching stop film 20 material, and the use of a material different from the type of light-shielding film 30 and the light-transmitting substrate 10, can effectively prevent excessive etching of the light-transmitting substrate 10 and improve the uniformity of optical performance during the pattern transfer process.

[0106] When the mask blank provided by the present application is used in the manufacturing process of a binary mask, due to the setting of the hard mask 40 in the present application, the loss of the resist film 50 can be reduced, and the thickness of the resist film 50 can be reduced, thereby achieving the effect of high resolution and small line width. Compared with other types, the use of the hard mask 40 of the above type is conducive to reducing the thickness of the resist film and reducing the loss of the resist film during the patterning process.

[0107] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.

[0108] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A mask blank, characterized in that: The mask blank comprises a light-transmitting substrate (10), an etching stop film (20), a light-shielding film (30) and a hard mask film (40) which are stacked in sequence, wherein: The material of the etching stop film (20) comprises a metal element and a non-metal element, and the metal element is selected from Cr, Ta, Hf, Zr, Al, W or Ni; The material of the light shielding film (30) includes molybdenum silicon compound and non-metallic elements; the optical density of the etching stop film (20) and the light shielding film (30) under an exposure light source with a wavelength of ≤250nm is ≥3.0, and the surface reflectivity is ≤40%; The material of the hard mask (40) includes Cr and non-metallic elements; The non-metallic element is selected from one or more of O, N, C, B and P.

2. The mask blank according to claim 1, characterized in that The etching stop film (20) is a single-layer or multi-layer structure with a thickness of 1 to 10 nm. In each layer of the etching stop film (20), the atomic percentage content of Cr is ≥30 at.%, the atomic percentage content of C is ≤15 at.%, and the remainder is other elements.

3. The mask blank according to claim 1, characterized in that The shading film (30) is a double-layer structure with a thickness of 40 to 70 nm, wherein the film layer close to the etching stop film (20) is a shading layer, and the film layer away from the etching stop film (20) is an anti-reflection layer, wherein the atomic percentage content of Mo in the shading layer is ≥8 at.%, the atomic percentage content of Si is ≥45 at.%, the atomic percentage content of N is ≤37 at.%, and the atomic percentage content of O is ≤10 at.%; the atomic percentage content of Mo in the anti-reflection layer is ≤10 at.%, the atomic percentage content of Si is ≥40 at.%, the atomic percentage content of N is ≥25 at.%, and the atomic percentage content of O is ≤25 at.%; the thickness of the shading layer is 38 to 60 nm, and the thickness of the anti-reflection layer is 2 to 20 nm.

4. The mask blank according to claim 1, characterized in that The light-shielding film (30) is a three-layer structure with a thickness of 40 to 70 nm, and comprises a first light-shielding layer, a second light-shielding layer and an anti-reflection layer in sequence, wherein the first light-shielding layer is arranged on a side surface close to the etching stop film (20), the anti-reflection layer is arranged on a side surface close to the hard mask (40), and the atomic percentage content of N in the second light-shielding layer is lower than the atomic percentage content of N in the first light-shielding layer; wherein the atomic percentage content of Mo in the first light-shielding layer and the second light-shielding layer is ≥10 at.%, the atomic percentage content of Si is ≥45 at.%, the atomic percentage content of N is ≤30 at.%, and the atomic percentage content of O is ≤5 at.%; the atomic percentage content of Mo in the anti-reflection layer is ≤10 at.%, the atomic percentage content of Si is ≥40 at.%, the atomic percentage content of N is ≥25 at.%, and the atomic percentage content of O is ≤25 at.%; the sum of the thicknesses of the first light-shielding layer and the second light-shielding layer is 38 to 60 nm, and the thickness of the anti-reflection layer is 2 to 20 nm.

5. The mask blank according to claim 1, characterized in that The hard mask (40) is a single-layer structure or a multi-layer structure, and has a thickness of 2 to 10 nm.

6. The mask blank according to claim 5, characterized in that The hard mask (40) is a single-layer structure, wherein the atomic percentage content of Cr is ≥50 at.%; or, The hard mask (40) is a double-layer structure, wherein the atomic percentage content of Cr in the film layer on the side close to the light shielding film (30) is higher than the atomic percentage content of Cr in the film layer on the side away from the light shielding film (30); or, The hard mask (40) has a three-layer structure, wherein the atomic percentage content of Cr in the middle layer is higher than the atomic percentage content of Cr in the other two adjacent layers, and the atomic percentage content of Cr in the middle layer is ≥50 at.%.

7. The mask blank according to claim 1, characterized in that The mask blank further comprises a resist film (50), wherein the resist film (50) is arranged on a surface of the hard mask film (40) on a side away from the light-transmitting substrate (10); The thickness of the resist film (50) is 60-200 nm.

8. A method for manufacturing a mask blank, characterized in that: The manufacturing method comprises: depositing an etching stop film (20), a light shielding film (30) and a hard mask film (40) on a surface of one side of a light-transmitting substrate (10) in sequence to obtain the mask blank; wherein the etching stop film (20), the light shielding film (30) and the hard mask film (40) have the same definitions as those in claim 1.

9. The method for manufacturing a mask blank according to claim 8, characterized in that: The deposition is carried out by magnetron sputtering. During the deposition of the etching stop film (20), the light shielding film (30) and the hard mask film (40), the working pressure is independently 0.1 to 0.4 Pa, the sputtering power is independently 200 to 3500 W, and the working gas is independently one or more of Ar, He, Xe, O2, N2, N2O, NO, NO2, CO2, CO, and CH4.

10. A method for manufacturing a binary mask, characterized in that: The binary mask is manufactured using the mask blank according to claim 1 as a raw material, and the manufacturing method comprises: Step S1, coating a resist on the surface of the hard mask (40) in the mask blank away from the light-transmitting substrate (10) to form a resist film (50), and sequentially performing exposure, baking and development to obtain a first stacked structure containing a patterned resist film (51); Step S2, using the patterned resist film (51) in the first stacked structure as a mask, etching the hard mask film (40) in the first stacked structure, and obtaining a second stacked structure including the patterned hard mask film (41) after cleaning and removing the patterned resist film (51); Step S3, using the patterned hard mask film (41) in the second stacked structure as a mask, etching the light shielding film (30) in the second stacked structure to obtain a third stacked structure containing the patterned light shielding film (31); Step S4, using the patterned shading film (31) in the third stacked structure as a mask, etching the etching stop film (20) in the third stacked structure, during the etching process in step S4, the patterned hard mask (41) is removed, and after cleaning, the binary mask containing the patterned etching stop film (21) is obtained.

11. A binary mask, characterized in that: The binary mask is manufactured by the method for manufacturing a binary mask according to claim 10.

Images