Super-resolution lithography structure, preparation method and pattern transfer method

Abstract

The present invention provides a super-resolution lithography structure, a preparation method and a method for pattern transfer, the preparation method comprising: S1, forming a dielectric layer (2) on a substrate (1); S2, depositing a graphene oxide layer on the dielectric layer (2); S3, baking and annealing the graphene oxide layer to form a reduced graphene oxide film layer (3), the reduced graphene oxide film layer (3) serving as a first hard mask layer; S4, coating a Si-containing anti-reflection coating (4) on the reduced graphene oxide film layer (3), the Si-containing anti-reflection coating (4) serving as a second hard mask layer; S5, sequentially depositing a metal layer (5) and coating a photosensitive layer (6) on the Si-containing anti-reflection coating (4) to obtain a super-resolution lithography structure. The method disclosed in the present invention improves the etching selectivity between the reduced graphene oxide film layer and the dielectric layer, and avoids problems such as pattern collapse and deformation caused by excessively high aspect ratios in super-resolution lithography pattern transfer.

Description

Technical Field

[0001] The present disclosure relates to the technical field of super-resolution lithography, and in particular to a super-resolution lithography structure, a preparation method and a pattern transfer method. Background Art

[0002] In recent years, with the development of miniaturization and integration of semiconductor devices, the resolution of electronic components has been required to be continuously improved. The improvement of device resolution will lead to a decrease in the focal depth of the lithography pattern, and then the thickness of the photosensitive film layer is required to be gradually thinner in the actual lithography process. In the process of transferring the graphic structure, the thin photosensitive film is easily consumed, and the transfer of the pattern cannot be effectively achieved. To this end, the general method is to add one or a group of film layer structures with excellent etching resistance between the photosensitive film layer and the etched layer, and use this etching-resistant film layer structure and the high etching selectivity of the underlying material to achieve conformal transfer of the pattern. This film layer is also called a hard mask layer.

[0003] The hard mask layer usually used in advanced process technology is a combined film system of Si-containing anti-reflection layer and spin-on carbon (SiBARC / SOC). Due to the insufficient etching selectivity of the SOC layer and the bottom etched layer, a relatively high thickness is required to achieve the transfer of the pattern. However, for the graphics of super-resolution lithography, the line width becomes narrower, while the height of the SOC layer remains unchanged, making the aspect ratio of the pattern higher. Based on this, the SOC layer as a hard mask layer will have problems such as bowing and wiggling during the etching process. Summary of the invention

[0004] 1. Technical issues to be resolved

[0005] In view of the above problems, the present disclosure provides a super-resolution lithography structure, a preparation method and a method for pattern transfer, which are used to solve the technical problems that the traditional hard mask layer is prone to distortion and collapse during the etching process.

[0006] (II) Technical solution

[0007] On the one hand, the present disclosure provides a method for preparing a super-resolution lithography structure, comprising: S1, forming a dielectric layer on a substrate; S2, depositing a graphene oxide layer on the dielectric layer; S3, baking and annealing the graphene oxide layer to form a reduced graphene oxide thin film layer, and the reduced graphene oxide thin film layer serves as a first hard mask layer; S4, coating a Si-containing anti-reflection coating on the reduced graphene oxide thin film layer, and the Si-containing anti-reflection coating serves as a second hard mask layer; S5, sequentially depositing a metal layer and coating a photosensitive layer on the Si-containing anti-reflection coating to obtain a super-resolution lithography structure.

[0008] Further, S2 includes: S21, mixing graphene oxide powder and a solvent to form a graphene oxide dispersion; S22, dropping the graphene oxide dispersion on the dielectric layer, and rotating at a low speed to evenly spread the graphene oxide dispersion; S23, rotating at a high speed to evaporate the solvent to form a graphene oxide layer.

[0009] Furthermore, the solvent in S21 includes one of deionized water, ethanol, tetrahydrofuran, isopropanol, ethanol, N,N-dimethylformamide, and N-methylpyrrolidone; and the concentration of the graphene oxide dispersion is 1 to 10 mg / mL.

[0010] Further, S3 includes: baking and annealing the graphene oxide layer, the baking and annealing is performed in a N2 or H2 atmosphere, the baking and annealing temperature is 200 to 800°C, and the baking and annealing time is 0.5 to 5 hours.

[0011] Further, S3 includes: forming a reduced graphene oxide thin film layer with a thickness of 1 to 50 nm.

[0012] Furthermore, the method of depositing a metal layer on the Si-containing anti-reflective coating in S5 includes electron beam evaporation or magnetron sputtering deposition; and the material of the metal layer includes one of Ag and Al.

[0013] Furthermore, after coating the photosensitive layer, S5 further includes: depositing a surface metal layer on the photosensitive layer.

[0014] On the other hand, the present disclosure provides a method for pattern transfer of a super-resolution lithography structure obtained according to the above-mentioned method for preparing a super-resolution lithography structure, comprising: S6, exposing and developing a photosensitive layer to form a lithography pattern structure; S7, etching a metal layer and a Si-containing anti-reflection coating in sequence, and removing the metal layer; S8, under an oxygen-containing plasma gas, using the etched Si-containing anti-reflection coating as a second hard mask layer and using reactive ion etching or inductively coupled plasma etching to reduce a graphene oxide film layer, and removing the Si-containing anti-reflection coating; S9, etching a dielectric layer using the etched reduced graphene oxide film layer as a first hard mask layer, and finally transferring the lithography pattern structure to the dielectric layer or the dielectric layer and the substrate to complete the pattern transfer.

[0015] Furthermore, the method for etching the metal layer in S7 includes ion beam etching, and the etching gas is argon; the method for etching the Si-containing anti-reflective coating includes one of ion beam etching, reactive ion etching and inductively coupled plasma etching, and the etching gas is one or more of SF6, CHF3 and Ar.

[0016] Furthermore, the method of etching the dielectric layer in S9 includes one of ion beam etching, reactive ion etching and inductively coupled plasma etching, and the etching gas is one or more of SF6, CHF3 and Ar.

[0017] Another aspect of the present disclosure provides a method for pattern transfer of a super-resolution lithography structure obtained according to the above-mentioned method for preparing a super-resolution lithography structure, comprising: S6, exposing a photosensitive layer, removing a surface metal layer and then developing to form a lithography pattern structure; S7, etching the metal layer and the Si-containing anti-reflection coating in sequence, and removing the metal layer; S8, under an oxygen-containing plasma gas, using the etched Si-containing anti-reflection coating as a second hard mask layer and using reactive ion etching or inductively coupled plasma etching to reduce the graphene oxide film layer, and removing the Si-containing anti-reflection coating; S9, etching the dielectric layer using the etched reduced graphene oxide film layer as a first hard mask layer, and finally transferring the lithography pattern structure to the dielectric layer or the dielectric layer and the substrate to complete the pattern transfer.

[0018] Another aspect of the present disclosure provides a super-resolution lithography structure, which is prepared according to the above-mentioned method for preparing the super-resolution lithography structure.

[0019] (III) Beneficial effects

[0020] The super-resolution lithography structure, preparation method and pattern transfer method disclosed in the present invention use a reduced graphene oxide film layer as the first hard mask layer and a Si-containing anti-reflection coating as the second hard mask layer. The etching of the lower layer can be achieved by alternately setting a carbon layer and a silicon layer with a large etching ratio difference. The reduced graphene oxide film layer material contains a large number of aromatic ring C atoms, has a high energy barrier, has a high impermeability to reactive gases, and has high etching resistance. The reduced graphene oxide film layer improves the etching selectivity between the reduced graphene oxide film layer and the dielectric layer, avoids the problems of pattern collapse and deformation caused by excessively high aspect ratio in super-resolution lithography, and thus the super-resolution lithography pattern structure can be transferred to the dielectric layer using a thin hard mask layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 A flow chart schematically shows a method for preparing a super-resolution lithography structure according to an embodiment of the present disclosure;

[0022] Figure 2 A flowchart of a method for pattern transfer for a super-resolution lithography structure according to an embodiment of the present disclosure is schematically shown;

[0023] Figure 3 A flowchart of super-resolution lithography pattern transfer according to an embodiment of the present disclosure is schematically shown;

[0024] Figure 4 Schematically showing a scanning electron microscope image during the super-resolution lithography pattern transfer process according to Example 1 of the present disclosure;

[0025] Figure 5 A cross-sectional view of a photolithography pattern structure obtained in Example 1 of the present disclosure is schematically shown. DETAILED DESCRIPTION

[0026] In order to make the objectives, technical solutions and advantages of the present disclosure more clearly understood, the present disclosure is further described in detail below in combination with specific embodiments and with reference to the accompanying drawings.

[0027] The terms used herein are only for describing specific embodiments and are not intended to limit the present disclosure. The terms "comprise", "include", etc. used herein indicate the existence of the features, steps, operations and / or components, but do not exclude the existence or addition of one or more other features, steps, operations or components.

[0028] In view of the low etching selectivity between the existing SOC layer as a hard mask layer and the etched layer, and the problem that a thicker SOC layer is prone to cause problems such as distortion and collapse of the graphic structure, the present disclosure aims to provide a super-resolution lithography structure, a preparation method and a lithography method.

[0029] The present disclosure provides a method for preparing a super-resolution lithography structure, see Figure 1 , including: S1, forming a dielectric layer 2 on a substrate 1; S2, depositing a graphene oxide layer on the dielectric layer 2; S3, baking and annealing the graphene oxide layer to form a reduced graphene oxide thin film layer 3, and the reduced graphene oxide thin film layer 3 serves as a first hard mask layer; S4, coating a Si-containing anti-reflection coating 4 on the reduced graphene oxide thin film layer 3, and the Si-containing anti-reflection coating 4 serves as a second hard mask layer; S5, depositing a metal layer 5 and coating a photosensitive layer 6 on the Si-containing anti-reflection coating 4 in sequence to obtain a super-resolution lithography structure.

[0030] The present invention sequentially forms a dielectric layer 2, a reduced graphene oxide film layer 3 (carbon-containing hard mask layer), a Si-containing anti-reflective coating 4 (SiBARC layer), a metal layer 5 and a photosensitive layer 6 on a substrate 1, and uses an etching-resistant reduced graphene oxide (Reduced Graphene Oxide, RGO) material to replace the existing SOC material as the first hard mask layer, and the Si-containing anti-reflective coating is used as the second hard mask layer. The etching of the lower layer can be achieved by alternating the carbon layer and the silicon layer with a large etching ratio difference. The molecular structure of graphene contains a large number of aromatic ring C atoms, has a high energy barrier, has a high impermeability to reactive gases, and has high etching resistance. Therefore, graphene is considered to be a good candidate material for a barrier layer. However, in actual processes, it is difficult to obtain a graphene film with uniform thickness on a large-size substrate.

[0031] Graphene oxide (GO) has high solubility due to the presence of functional groups and is suitable for solution-based processes. The preparation process of the GO film layer is simple, and the preparation process includes: taking a small amount of GO dispersion droplets and infiltrating on the substrate, first spreading the GO dispersion evenly on the substrate at a lower rotation speed, and then accelerating the evaporation of the solvent at a higher rotation speed to spread the GO film evenly on the substrate. However, based on the Ohnishi parameter, under dry etching conditions, CC bonds are more difficult to decompose than CO and C=O bonds. The higher the C / O ratio and C / H ratio, the higher the etching resistance. Therefore, the prepared GO film needs to be reduced at high temperature to reduce the proportion of O-containing functional groups. The reduced RGO has a high C content, which is crucial to improving the etching resistance.

[0032] Therefore, RGO as the first hard mask layer can significantly improve the etching ratio between the dielectric layer (etched layer). Taking the etched layer as SiO2 as an example, the research results show that the etching ratio of SOC / SiO2 is 2, and the etching ratio of RGO / SiO2 is 3-8, where the etching resistance of RGO increases with the increase of annealing temperature. More importantly, the RGO material can avoid pattern collapse and deformation in super-resolution lithography. The preparation method of the SiBARC / RGO multilayer structure disclosed in the present invention is simple, does not require harsh conditions such as high temperature and high pressure, does not require high-cost equipment, and has a low production cost.

[0033] Specifically, S1 includes: preparing a dielectric layer 2 on a substrate 1 by thermal oxidation, electron beam evaporation, magnetron sputtering deposition, chemical vapor deposition or coating. The material of the dielectric layer 2 is one or more of SiO2, SiN, poly-Si, and Al2O3, and the thickness of the dielectric layer 2 is 10 to 500 nm.

[0034] On the basis of the above embodiment, S2 includes: S21, mixing graphene oxide powder and solvent to form graphene oxide dispersion; S22, dropping the graphene oxide dispersion on the dielectric layer 2, and rotating at a low speed to evenly spread the graphene oxide dispersion; S23, rotating at a high speed to evaporate the solvent to form a graphene oxide layer. The solvent in S21 includes one of deionized water, ethanol, tetrahydrofuran, isopropanol, ethanol, N,N-dimethylformamide, and N-methylpyrrolidone; the concentration of the graphene oxide dispersion is 1 to 10 mg / mL.

[0035] GO dispersion is prepared by mixing a certain amount of GO powder prepared by the Hummers method with a solvent, and then ultrasonically preparing a GO dispersion; the solvent mixed with GO is one of deionized water, ethanol, tetrahydrofuran, isopropanol, ethanol, N,N-dimethylformamide, and N-methylpyrrolidone. Preferably, the concentration of the GO dispersion is 1 to 10 mg / mL, and the concentration of the GO dispersion has a uniform dispersion technical effect within this range, and it is easier to obtain a dense and uniform GO film. This is because too high a concentration of the GO dispersion can easily cause GO to agglomerate in the solvent.

[0036] After preparing the GO dispersion, the GO film layer is deposited by spin coating. Take the GO dispersion with a pipette, drop it on the substrate and soak it for a certain time, such as 1 minute; rotate it at a lower rotation speed for a certain time, such as 1 minute, the rotation speed range is such as 500rmp~700rmp, so that the GO dispersion is evenly spread on the substrate; then rotate it at a higher rotation speed for a certain time, such as 0.5 minute, the rotation speed range is such as 1200rmp~3000rmp, to accelerate the evaporation of the solvent, so that the GO film is evenly spread on the substrate to form a graphene oxide layer.

[0037] On the basis of the above embodiment, S3 includes: baking and annealing the graphene oxide layer in a N2 or H2 atmosphere, the baking and annealing temperature is 200 to 800° C., and the baking and annealing time is 0.5 to 5 hours.

[0038] The baking annealing step is performed at a temperature of 200°C to 800°C for 0.5 to 5 hours. Preferably, when the baking annealing step is at 200 to 500°C, the duration is preferably controlled within 3 to 5 hours; when the baking annealing step is at 500 to 800°C, the duration is preferably controlled within 30 minutes to 2 hours, and it can be performed under an atmosphere such as N2 or H2.

[0039] On the basis of the above embodiment, S3 includes: forming a reduced graphene oxide thin film layer 3 with a thickness of 1 to 50 nm.

[0040] The thickness of the reduced graphene oxide film layer 3 within this range can realize the transfer of patterns in super-resolution lithography, while the thickness of the SOC layer needs to be within the range of 100 to 150 nm. It can be seen that the reduced graphene oxide film layer is beneficial to avoid problems such as pattern collapse and deformation caused by excessively high aspect ratios.

[0041] On the basis of the above embodiment, the method of depositing the metal layer 5 on the Si-containing anti-reflection coating 4 in S5 includes electron beam evaporation or magnetron sputtering deposition; the material of the metal layer 5 includes one of Ag and Al.

[0042] Furthermore, a Si-containing anti-reflection coating 4 is formed on the RGO film layer by a coating method. The Si-containing anti-reflection coating 4 acts as a hard mask and is disposed on the RGO film layer because a thin photoresist is used in super-resolution lithography, and the thin photoresist is consumed before the RGO layer is completely etched; a metal layer 5 is deposited on the above-mentioned Si-containing anti-reflection coating 4 by electron beam evaporation or magnetron sputtering deposition. Preferably, the material of the metal layer 5 is one of Ag and Al; the metal layer 5 is disposed because the free electrons on the surface of the metal conductor are driven by photons to coherently resonate, thereby forming surface plasmons (SP) at the metal-medium interface. When the evanescent wave vector is the same as the SP wave vector, the two will coherently resonate, so that the evanescent wave carrying subwavelength spatial information is enhanced, so that super-resolution imaging can be achieved through regulation, and finally a photosensitive layer 6 is formed on the above-mentioned metal layer 5 by a coating method to obtain a complete super-resolution lithography structure.

[0043] On the basis of the above embodiment, after coating the photosensitive layer 6 , S5 further includes: depositing a surface metal layer on the photosensitive layer 6 .

[0044] At this point, the super-resolution lithography structure includes, from bottom to top, a substrate 1, a dielectric layer 2, a reduced graphene oxide thin film layer 3, a Si-containing anti-reflective coating 4, a metal layer 5, a photosensitive layer 6 and a surface metal layer, wherein the metal layer 5, the photosensitive layer 6 and the surface metal layer constitute a resonant cavity imaging structure of metal / photoresist / metal, which is conducive to obtaining an imaging lithography effect with higher resolution and contrast.

[0045] The present disclosure also provides a method for pattern transfer using a super-resolution lithography structure obtained by the above-mentioned method for preparing the super-resolution lithography structure, see Figure 2-Figure 3, including: S6, exposing and developing the photosensitive layer 6 to form a photolithographic pattern structure; S7, etching the metal layer 5 and the Si-containing anti-reflective coating 4 in sequence, and removing the metal layer 5; S8, under an oxygen-containing plasma gas, using the etched Si-containing anti-reflective coating 4 as a second hard mask layer and using reactive ion etching or inductively coupled plasma etching to reduce the graphene oxide film layer 3, and removing the Si-containing anti-reflective coating 4; S9, using the etched reduced graphene oxide film layer 3 as a first hard mask layer to etch the dielectric layer 2, and finally transferring the photolithographic pattern structure to the dielectric layer 2 or the dielectric layer 2 and the substrate 1 to complete the pattern transfer.

[0046] The present invention forms a dielectric layer 2, a reduced graphene oxide film layer 3, a Si-containing anti-reflection coating 4, a metal layer 5 and a photosensitive layer 6 on a substrate 1 in sequence, and then forms a photolithographic pattern structure in the photosensitive layer 6, and then etches downward layer by layer from top to bottom, with the upper layer serving as an etching mask for the lower layer. After the lower layer is etched, the upper layer is removed, and etching continues downward, and the photolithographic pattern structure in the photosensitive layer 6 is sequentially etched and transferred to the metal layer 5, the Si-containing anti-reflection coating 4, the reduced graphene oxide film layer 3 and the dielectric layer 2 (or the dielectric layer 2 and the substrate 1), completing the pattern transfer. This method of etching and transferring through a multi-layer structure has the advantages of simple preparation process, low production cost and high production capacity.

[0047] Based on the above embodiments, the method for etching the metal layer 5 in S7 includes ion beam etching (IBE), and the etching gas is argon; the method for etching the Si-containing anti-reflective coating 4 includes one of ion beam etching (IBE), reactive ion etching (RIE) or inductively coupled plasma etching (ICP), and the etching gas is one or more of SF6, CHF3 and Ar.

[0048] In S7, IBE is used to etch the metal layer 5, and the pattern on the photosensitive layer 6 is transferred to the metal layer 5; preferably, argon is used as the etching gas. IBE, RIE or ICP is used to etch the Si-containing anti-reflective coating 4, and the photolithographic pattern structure in the metal layer 5 is transferred to the SiBARC layer; the etching gas can be one or more of SF6, CHF3 and Ar. After the SiBARC layer is etched, the metal layer 5 is removed by wet etching or mechanical stripping.

[0049] In S8, the RGO film layer is etched by RIE or ICP under the plasma gas containing O2, and the photolithographic pattern structure in the SiBARC layer is further transferred to the RGO layer. After the RGO layer is etched, the SiBARC layer is removed by wet etching. Preferably, the etching solution is HF solution.

[0050] Based on the above embodiment, the method for etching the dielectric layer 2 in S9 includes one of ion beam etching, reactive ion etching and inductively coupled plasma etching, and the etching gas is one or more of SF6, CHF3 and Ar.

[0051] The material of the dielectric layer 2 includes SiO2, SiN, poly-Si, Al2O3, and can be etched by RIE or ICP method. The etching gas can be one or more of SF6, CHF3 and Ar, or a combination of CF4 / O2 and NF3 / O2.

[0052] The present disclosure also provides a method for pattern transfer using a super-resolution lithography structure obtained by the above-mentioned method for preparing the super-resolution lithography structure, comprising:

[0053] S6, exposing the photosensitive layer 6, removing the surface metal layer and then developing to form a photolithographic pattern structure; S7, etching the metal layer 5 and the Si-containing anti-reflective coating 4 in sequence, and removing the metal layer 5; S8, under an oxygen-containing plasma gas, using the etched Si-containing anti-reflective coating 4 as the second hard mask layer and using reactive ion etching or inductively coupled plasma etching to reduce the graphene oxide film layer 3, and remove the Si-containing anti-reflective coating 4; S9, using the etched reduced graphene oxide film layer 3 as the first hard mask layer to etch the dielectric layer 2, and finally transferring the photolithographic pattern structure to the dielectric layer 2 or the dielectric layer 2 and the substrate 1 to complete the pattern transfer.

[0054] If a surface metal layer is prepared on the photosensitive layer 6, the surface metal layer needs to be removed in S6 before the development step is performed. The subsequent steps are the same as the method for super-resolution lithography structure pattern transfer without a surface metal layer, and will not be repeated here.

[0055] The present disclosure also provides a super-resolution lithography structure, which is prepared according to the above-mentioned method for preparing the super-resolution lithography structure.

[0056] The super-resolution lithography structure disclosed in the present invention is resistant to etching and can be used not only in the manufacturing process of cutting-edge logic chips using super-resolution lithography, but also in the field of CMOS processes at higher technology nodes.

[0057] The present disclosure is further described below through specific implementation methods. The above-mentioned super-resolution lithography structure, preparation method and pattern transfer method are specifically described in the following examples. However, the following examples are only used to illustrate the present disclosure, and the scope of the present disclosure is not limited thereto.

[0058] The method for preparing the super-resolution lithography structure and the method for pattern transfer disclosed in the present invention are as follows: Figure 1 to Figure 3 As shown, the following steps are performed in sequence:

[0059] Step 1: Prepare a dielectric layer 2 on a substrate 1 by thermal oxidation, electron beam evaporation, magnetron sputtering deposition, chemical vapor deposition or coating. The material of the dielectric layer 2 is one or more of SiO2, SiN, poly-Si, Al2O3, and the thickness of the dielectric layer 2 is 10 to 500 nm; equivalent to the above step S1.

[0060] Step 2: Prepare GO dispersions of different concentrations and deposit a graphene oxide (GO) layer on the dielectric layer 2 by spin coating, spray coating, a combination of spin coating and spray coating, printing, etc.; bake the GO film layer at different temperatures to form a reduced graphene oxide thin film layer 3, which serves as a first hard mask layer; this is equivalent to the above steps S2 to S3.

[0061] Step 3: forming a Si-containing anti-reflection coating 4 on the reduced graphene oxide film layer 3 by a coating method, wherein the Si-containing anti-reflection coating 4 serves as a second hard mask layer; this is equivalent to the above step S4;

[0062] Step 4: depositing a metal layer 5 on the Si-containing anti-reflection coating 4 by electron beam evaporation or magnetron sputtering deposition. Preferably, the material of the metal layer 5 is one of Ag and Al.

[0063] Step 5: forming a photosensitive layer 6 on the metal layer 5 by a coating method, thereby completing the preparation of the super-resolution lithography structure; equivalent to the above step S5.

[0064] Step 6: exposing and developing the photosensitive layer 6 in the multilayer film structure to obtain the required photolithography pattern structure; equivalent to the above step S6;

[0065] Step 7: Etch the metal layer 5 by IBE to transfer the photolithographic pattern structure in the photosensitive layer 6 to the metal layer 5; preferably, the etching gas is argon. Etch the Si-containing anti-reflective coating 4 by IBE, RIE or ICP to transfer the photolithographic pattern structure in the metal layer 5 to the Si-containing anti-reflective coating 4; the etching gas can be one or more of SF6, CHF3 and Ar; then remove the metal layer 5 by wet etching and mechanical stripping; equivalent to the above step S7;

[0066] Step 8: Under the plasma gas containing O2, the reduced graphene oxide film layer 3 is etched by RIE or ICP, the photolithographic pattern structure in the Si-containing anti-reflection coating 4 is transferred to the reduced graphene oxide film layer 3, and the silicon-containing anti-reflection coating 4 is removed; which is equivalent to the above step S8;

[0067] Step 9: Use IBE, RIE or ICP to etch the underlying dielectric layer 2 or the dielectric layer 2 and the substrate 1 to transfer the photolithographic pattern structure in the reduced graphene oxide film layer 3 to the underlying dielectric layer 2 or the dielectric layer 2 and the substrate 1; the etching gas can be one or more of SF6, CHF3 and Ar; which is equivalent to the above step S9.

[0068] According to the above steps 1 to 9, three specific embodiments are provided below.

[0069] Embodiment 1:

[0070] The steps for preparing the super-resolution lithography structure and forming its pattern in this embodiment are as follows:

[0071] Step 1: Depositing a dielectric layer 2 on a substrate 1 by electron beam evaporation, the dielectric layer 2 being SiO2 with a thickness of 200 nm;

[0072] Step 2: Spin-coat a graphene oxide film at a rotation speed of 1500 rpm for 30 seconds, repeat 10 times, and bake and anneal at 240°C for 3 hours to form a 30 nm thick reduced graphene oxide (RGO); the concentration of the GO dispersion used is 5 mg / mL, and the solvent is ethanol.

[0073] Step 3: The silicon-containing anti-reflection coating 4 is prepared by a spin coating process, the rotation speed is 2000 rpm, the spin coating time is 30 seconds, and the coating is baked on a hot plate at 210° C. for 2 minutes. The thickness of the silicon-containing anti-reflection coating 4 is 30 nm;

[0074] Step 4: depositing a metal layer 5 with a thickness of 40 nm by magnetron sputtering, wherein the metal layer 5 is an Ag layer, wherein the DC power is 50 W;

[0075] Step 5: Prepare the photosensitive layer 6 by spin coating, with a rotation speed of 4000 rpm and a spin coating time of 40 s. Bake on a hot plate at 100° C. for 3 minutes. The thickness of the obtained photoresist is 30 nm. The preparation of the super-resolution lithography structure is now completed.

[0076] Step 6: Expose and develop the photosensitive layer 6 with an exposure dose of 70 mJ to obtain a grating structure with a half-period of 200 nm.

[0077] Step 7: Use IBE etching to transfer the photolithographic pattern structure in the photosensitive layer 6 to the Ag layer, select an ion beam current of 260 mA, an incident angle of 10° (the angle between the normal line of the substrate and the ion beam current), and use 14 sccm Ar gas for etching; remove the photosensitive layer 6;

[0078] Step 8: The photolithographic pattern structure is further transferred to the silicon-containing anti-reflective coating 4 by RIE etching, and etching is performed using 20 W of RF power and 20 sccm of CHF3 gas;

[0079] Step 9: Prepare a 1:1 HNO3:DI aqueous solution, soak the above sample for 30 seconds, then rinse it and blow it dry with N2 to remove the Ag layer;

[0080] Step 10: Using RIE etching to further transfer the photolithographic pattern structure to the reduced graphene oxide film layer 3, etching is performed using 20W RF power and 20sccm O2 gas; using HF solution to remove the silicon-containing anti-reflective coating 4;

[0081] Step 11: Use RIE etching to further transfer the photolithography pattern structure to the SiO2 layer, and use 20W RF power and 20sccm CHF3 gas for etching.

[0082] Figure 4 This is an electron microscope image showing that the grating structure in the photosensitive layer 6 in this embodiment is transferred to the silicon-containing anti-reflection coating 4, the reduced graphene oxide thin film layer 3 and the SiO2 layer completely without distortion or deformation. Figure 5 is a cross-sectional view of the photolithography pattern structure obtained in this embodiment.

[0083] The super-resolution lithography structure, preparation method and pattern transfer method provided in this embodiment can transfer the grating pattern to the 126nm SiO2 layer (such as the 30nm thick RGO layer) by etching based on the highly etch-resistant RGO film layer. Figure 5 As shown in Figure 2, the etching ratio reaches 4:1. Compared with the CVD process, the spin coating hard mask process has the advantages of low initial investment cost, uniform coating, easy control of coating thickness and ability to shorten process time.

[0084] Embodiment 2:

[0085] The steps for preparing the super-resolution lithography structure and forming its pattern in this embodiment are as follows:

[0086] Step 1: Depositing a dielectric layer 2 on a substrate 1 by electron beam evaporation, the dielectric layer 2 is SiO2 with a thickness of 100 nm;

[0087] Step 2: Spin-coat the graphene oxide film at a speed of 2000 rpm for 30 seconds, repeat 6 times, and bake and anneal at 600°C for 2 hours to form a 15 nm thick reduced graphene oxide (RGO); the concentration of the GO dispersion used is 8 mg / mL, and the solvent is N,N-dimethylformamide.

[0088] Step 3: Prepare the silicon-containing anti-reflection coating 4 by spin coating, the rotation speed is 4000 rpm, the spin coating time is 30 seconds, and bake on a hot plate at 210° C. for 2 minutes. The thickness of the silicon-containing anti-reflection coating 4 is 20 nm;

[0089] Step 4: Deposit a bottom metal layer 5 with a thickness of 40 nm by magnetron sputtering, wherein the metal layer 5 is an Ag layer, wherein the DC power is 50 W;

[0090] Step 5: Prepare the photosensitive layer 6 by spin coating, with a rotation speed of 4000 rpm and a spin coating time of 40 s. Bake on a hot plate at 100° C. for 3 minutes. The thickness of the obtained photoresist is 30 nm. The preparation of the super-resolution lithography structure is now completed.

[0091] Step 6: Expose and develop the photosensitive layer 6 with an exposure dose of 80 mJ to obtain a grating structure with a half-period of 120 nm.

[0092] Step 7: Use IBE etching to transfer the photolithographic pattern structure in the photosensitive layer 6 to the underlying Ag layer. The selected ion beam current is 260 mA, the incident angle is 10° (the angle between the normal line of the substrate and the ion beam current), and 14 sccm Ar gas is used for etching; remove the photosensitive layer 6;

[0093] Step 8: The photolithographic pattern structure is further transferred to the silicon-containing anti-reflective coating 4 by RIE etching, and etching is performed using 20 W of RF power and 20 sccm of CHF3 gas;

[0094] Step 9: Prepare a 1:1 HNO3:DI aqueous solution, soak the above sample for 30 seconds, then rinse it and blow it dry with N2 to remove the Ag layer;

[0095] Step 10: Using RIE etching to further transfer the photolithographic pattern structure to the reduced graphene oxide film layer 3, etching is performed using 20W RF power and 20sccm O2 gas; using HF solution to remove the silicon-containing anti-reflective coating 4;

[0096] Step 11: Use RIE etching to further transfer the photolithography pattern structure to the SiO2 layer, and use 20W RF power and 20sccm CHF3 gas for etching.

[0097] Based on the highly etch-resistant RGO film layer, this embodiment can utilize a 15 nm thick RGO layer to etch and transfer the grating pattern to a 100 nm thick SiO2 layer, with an etching ratio of 6:1.

[0098] Embodiment 3:

[0099] This embodiment describes the preparation of super-resolution lithography patterns and the etching transfer process, and the implementation steps are as follows:

[0100] Step 1: Depositing a dielectric layer 2 on a substrate 1 by electron beam evaporation, the dielectric layer 2 being SiO2 with a thickness of 200 nm;

[0101] Step 2: Spin-coat a graphene oxide film at a rotation speed of 1500 rpm for 30 seconds, repeat 15 times, and bake and anneal at 600°C for 2 hours to form a 30 nm thick reduced graphene oxide (RGO); the concentration of the GO dispersion used is 3 mg / mL, and the solvent is deionized water.

[0102] Step 3: The silicon-containing anti-reflection coating 4 is prepared by a spin coating process, the rotation speed is 2000 rpm, the spin coating time is 30 seconds, and the coating is baked on a hot plate at 210° C. for 2 minutes. The thickness of the silicon-containing anti-reflection coating 4 is 30 nm;

[0103] Step 4: depositing a metal layer 5 with a thickness of 40 nm by magnetron sputtering, wherein the metal layer 5 is an Ag layer, wherein the DC power is 50 W;

[0104] Step 5: Prepare the photosensitive layer 6 by spin coating, with a rotation speed of 4000 rpm and a spin coating time of 40 s. Bake on a hot plate at 100° C. for 3 minutes. The thickness of the obtained photoresist is 30 nm.

[0105] Step 6: Use vacuum evaporation to deposit a surface metal layer with a thickness of 12nm, the surface metal layer is Ag, and the deposition rate is 0.3nm / s; thus, the preparation of the resonant cavity structure of super-resolution lithography is completed. The use of the metal / photoresist / metal resonant cavity imaging structure can further improve the resolution because the upper and lower metal film layers SP are coupled to each other, which helps to further improve the SP excitation efficiency and compress the SP wavelength, thereby obtaining a higher resolution and contrast SP imaging lithography effect.

[0106] Step 7: Expose the photosensitive layer 6 with an exposure dose of 200 mJ, remove the surface Ag with HNO3 and develop, and obtain a through-hole structure with a diameter of 65 nm.

[0107] Step 8: Use IBE etching to transfer the photolithographic pattern structure in the photosensitive layer 6 to the Ag layer, select an ion beam current of 260 mA, an incident angle of 10° (the angle between the normal line of the substrate and the ion beam current), and use 14 sccm Ar gas for etching; remove the photosensitive layer 6;

[0108] Step 9: The photolithographic pattern structure is further transferred to the silicon-containing anti-reflective coating 4 by RIE etching, and etching is performed using 20 W of RF power and 20 sccm of CHF3 gas;

[0109] Step 10: Prepare a 1:1 HNO3:DI aqueous solution, soak the above sample for 30 seconds, then rinse it and blow it dry with N2 to remove the Ag layer;

[0110] Step 11: using RIE etching to further transfer the photolithographic pattern structure to the reduced graphene oxide film layer 3, using 20W RF power and 20sccm O2 gas for etching; using HF solution to remove the silicon-containing anti-reflective coating 4;

[0111] Step 12: Use RIE etching to further transfer the photolithography pattern structure to the SiO2 layer, and use 20W RF power and 20sccm CHF3 gas for etching.

[0112] Based on the RGO film layer with high etching resistance, this embodiment can realize super-resolution lithography with a half-period of 65nm, and can further transfer the pattern to the RGO film layer and the SiO2 dielectric layer, and the etching selectivity ratio reaches 6:1.

[0113] The etching transfer process provided by the present lithography can not only successfully transfer the lithography pattern structure to the dielectric layer or the dielectric layer and the substrate, but also significantly improve the etching ratio of the hard mask layer and the dielectric layer. For patterns with finer sizes, it avoids the collapse and deformation of the C-containing layer when etching the dielectric layer, which affects the etching results and avoids the deterioration of device performance.

[0114] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present disclosure. It should be understood that the above description is only a specific embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A method for preparing a super-resolution lithography structure, characterized in that: include: S1, forming a dielectric layer (2) on a substrate (1); S2, depositing a graphene oxide layer on the dielectric layer (2); The S2 includes: S21, mixing graphene oxide powder and a solvent to form a graphene oxide dispersion; S22, dropping the graphene oxide dispersion onto the dielectric layer (2), and rotating at a low speed to evenly spread the graphene oxide dispersion; S23, rotating at a high speed to evaporate the solvent to form a graphene oxide layer; S3, baking and annealing the graphene oxide layer to form a reduced graphene oxide thin film layer (3), wherein the reduced graphene oxide thin film layer (3) serves as a first hard mask layer; wherein the reduced graphene oxide thin film layer (3) has a thickness of 1 to 50 nm; S4, coating a Si-containing anti-reflection coating (4) on the reduced graphene oxide thin film layer (3), wherein the Si-containing anti-reflection coating (4) serves as a second hard mask layer; S5, depositing a metal layer (5) and coating a photosensitive layer (6) in sequence on the Si-containing anti-reflection coating (4) to obtain a super-resolution lithography structure.

2. The method for preparing a super-resolution lithography structure according to claim 1, characterized in that: The solvent in S21 includes one of deionized water, ethanol, tetrahydrofuran, isopropanol, ethanol, N,N-dimethylformamide, and N-methylpyrrolidone; The concentration of the graphene oxide dispersion is 1-10 mg / mL.

3. The method for preparing a super-resolution lithography structure according to claim 1, characterized in that: The S3 includes: The graphene oxide layer is subjected to baking annealing, the baking annealing is performed in a N2 or H2 atmosphere, the baking annealing temperature is 200 to 800°C, and the baking annealing time is 0.5 to 5 hours.

4. The method for preparing a super-resolution lithography structure according to claim 1, characterized in that: The method of depositing the metal layer (5) on the Si-containing anti-reflection coating (4) in S5 comprises electron beam evaporation or magnetron sputtering deposition; The material of the metal layer (5) includes one of Ag and Al.

5. The method for preparing a super-resolution lithography structure according to claim 1, characterized in that: After coating the photosensitive layer (6), the step S5 further comprises: A surface metal layer is deposited on the photosensitive layer (6).

6. A method for pattern transfer of a super-resolution lithography structure obtained by the method for preparing a super-resolution lithography structure according to any one of claims 1 to 4, characterized in that: include: S6, exposing and developing the photosensitive layer (6) to form a photolithographic pattern structure; S7, etching the metal layer (5) and the Si-containing anti-reflection coating (4) in sequence, and removing the metal layer (5); S8, using the etched Si-containing anti-reflective coating (4) as a second hard mask layer and etching the reduced graphene oxide film layer (3) by reactive ion etching or inductively coupled plasma in the presence of oxygen-containing plasma gas, and removing the Si-containing anti-reflective coating (4); S9, etching the dielectric layer (2) using the etched reduced graphene oxide film layer (3) as a first hard mask layer, and finally transferring the photolithographic pattern structure to the dielectric layer (2) or the dielectric layer (2) and the substrate (1), thereby completing the pattern transfer.

7. The method for image transmission according to claim 6, characterized in that: The method of etching the metal layer (5) in S7 comprises ion beam etching, and the etching gas is argon gas; The method for etching the Si-containing anti-reflection coating (4) comprises one of ion beam etching, reactive ion etching and inductively coupled plasma etching, and the etching gas is one or more of SF6, CHF3 and Ar.

8. The method for image transmission according to claim 6, characterized in that: The method for etching the dielectric layer (2) in S9 comprises one of ion beam etching, reactive ion etching and inductively coupled plasma etching, and the etching gas is one or more of SF6, CHF3 and Ar.

9. A method for pattern transfer of a super-resolution lithography structure obtained by the method for preparing a super-resolution lithography structure according to claim 5, characterized in that: include: S6, exposing the photosensitive layer (6), removing the surface metal layer and then developing to form a photolithographic pattern structure; S7, etching the metal layer (5) and the Si-containing anti-reflection coating (4) in sequence, and removing the metal layer (5); S8, using the etched Si-containing anti-reflective coating (4) as a second hard mask layer and etching the reduced graphene oxide film layer (3) by reactive ion etching or inductively coupled plasma in the presence of oxygen-containing plasma gas, and removing the Si-containing anti-reflective coating (4); S9, etching the dielectric layer (2) using the etched reduced graphene oxide film layer (3) as a first hard mask layer, and finally transferring the photolithographic pattern structure to the dielectric layer (2) or the dielectric layer (2) and the substrate (1), thereby completing the pattern transfer.

10. A super-resolution lithography structure, characterized in that: The super-resolution lithography structure is prepared according to the method for preparing a super-resolution lithography structure according to any one of claims 1 to 5.

Images