WO2024060362A1 - Super-resolution photoetching structure, manufacturing method, and pattern transfer method - Google Patents

Abstract

Provided in the present disclosure are a super-resolution photoetching structure, a manufacturing method, and a pattern transfer method. The manufacturing method comprises: S1, forming a dielectric layer (2) on a substrate (1); S2, depositing a graphene oxide layer onto the dielectric layer (2); S3, roasting the graphene oxide layer and then annealing same to form a reduced graphene oxide thin film layer (3), the reduced graphene oxide thin film layer (3) serving as a first hard mask layer; S4, coating the reduced graphene oxide thin film layer (3) with an Si bottom anti-reflection coating (4), the Si bottom anti-reflection coating (4) serving as a second hard mask layer; and S5, sequentially depositing a metal layer (5) and coating a photosensitive layer (6) on the Si bottom anti-reflection coating (4) so as to obtain the super-resolution photoetching structure. The method of the present disclosure improves the etching selection ratio between the reduced graphene oxide thin film layer and the dielectric layer, thereby avoiding the problems of bowing, wiggling and the like of patterns caused by an excessively high aspect ratio during super-resolution photoetching pattern transfer.

Description

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

This disclosure claims priority from the Chinese patent application with application number 202211147820.4, filed on September 20, 2022, the entire content of which is incorporated into this disclosure by reference.

Technical field

The present disclosure relates to the technical field of super-resolution lithography, and specifically to a super-resolution lithography structure, a preparation method and a pattern transfer method.

Background technique

In recent years, with the development of miniaturization and integration of semiconductor devices, the resolution of electronic components has been continuously improved. The improvement of device resolution will lead to a reduction in the focal depth of lithography patterns, which in turn requires the thickness of the photosensitive film layer to gradually become thinner during the actual lithography process. In the process of transferring the graphic structure, the thin photosensitive film is easily consumed, and the transfer of the graphic cannot be effectively realized. To this end, a common method is to add one or a group of film structures with excellent etching resistance between the photosensitive film layer and the etched layer, and use this etching-resistant film structure to combine with the high etching of the underlying material. Selectivity to achieve conformal transfer of patterns, this film layer is also called a hard mask layer.

The hard mask layer usually used in advanced manufacturing processes is a Si-containing anti-reflection layer and spin-coated carbon (Si bottom anti-reflection coating/Spin-on-carbon: SiBARC/SOC) combined film system. Due to the insufficient etching selectivity ratio of the SOC layer and the bottom etched layer, a relatively high thickness is required to achieve pattern transfer. However, for super-resolution lithography patterns, 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 may have problems such as bowing and wiggling during the etching process.

Contents of the invention

(1) Technical problems to be solved

In response to the above problems, the present disclosure provides a super-resolution lithography structure, a preparation method and a pattern transfer method, which are used to solve technical problems such as distortion and collapse of traditional hard mask layers during the etching process.

(2) Technical solutions

On the one hand, the present disclosure provides a method for preparing a super-resolution photolithography structure, including: S1, forming a dielectric layer on a substrate; S2, depositing a graphene oxide layer on the dielectric layer; S3, baking the graphene oxide layer Bake annealing to form a reduced graphene oxide film layer, which serves as the first hard mask layer; S4, apply a Si-containing anti-reflective coating on the reduced graphene oxide film layer, and a Si-containing anti-reflective coating As the second hard mask layer; S5, a metal layer is sequentially deposited on the Si-containing anti-reflective coating and the photosensitive layer is coated to obtain a super-resolution lithography structure.

Further, S2 includes: S21, mix graphene oxide powder and solvent to form graphene oxide dispersion; S22, add graphene oxide dispersion droplets on the medium layer, and rotate at low speed to spread the graphene oxide dispersion evenly; S23, high-speed rotation causes the solvent to evaporate to form a graphene oxide layer.

Further, the solvent in S21 includes one of deionized water, ethanol, tetrahydrofuran, isopropyl alcohol, ethanol, N,N-dimethylformamide, and N-methylpyrrolidone; the concentration of the graphene oxide dispersion is 1～10mg/mL.

Further, S3 includes: baking and annealing the graphene oxide layer, the baking and annealing is performed in an N ₂ or H ₂ atmosphere, the baking and annealing temperature is 200-800°C, and the baking and annealing time is 0.5-5 hours. .

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

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

Further, after S5 coating the photosensitive layer, it also includes: depositing a surface metal layer on the photosensitive layer.

On the other hand, the present disclosure provides a method for pattern transfer of a super-resolution lithography structure obtained according to the aforementioned preparation method of a super-resolution lithography structure, including: S6, exposing and developing the photosensitive layer to form a lithography pattern structure; S7, etch the metal layer and Si-containing anti-reflective coating in sequence, and remove the metal layer; S8, use the etched Si-containing anti-reflective coating as the second hard mask layer under oxygen-containing plasma gas. Use reactive ion etching or inductively coupled plasma etching to reduce the graphene oxide film layer and remove the Si-containing anti-reflective coating; S9, use the etched reduced graphene oxide film layer as the first hard mask layer for etching The dielectric layer finally transfers the photolithography pattern structure to the dielectric layer or the dielectric layer and the substrate to complete the pattern transfer.

Furthermore, the method of etching the metal layer in S7 includes ion beam etching, and the etching gas uses argon; the method of etching the Si-containing anti-reflective coating includes ion beam etching, reactive ion etching and inductively coupled plasma etching. One or more of SF ₆ , CHF ₃ and Ar are used as the etching gas.

Further, the method for etching the dielectric layer in S9 includes one of ion beam etching, reactive ion etching and inductively coupled plasma etching. The etching gas uses one or more of SF ₆ , CHF ₃ and Ar. kind.

On the other hand, the present disclosure provides a method for pattern transfer of a super-resolution lithography structure obtained according to the aforementioned preparation method of a super-resolution lithography structure, including: S6, exposing the photosensitive layer, removing the surface metal layer, and then Develop to form a photolithography pattern structure; S7, etch the metal layer and Si-containing anti-reflective coating in sequence, and remove the metal layer; S8, use the etched Si-containing anti-reflective coating under oxygen-containing plasma gas As the second hard mask layer, reactive ion etching or inductively coupled plasma etching is used to etch the reduced graphene oxide film layer, and the Si-containing anti-reflective coating is removed; S9, the etched reduced graphene oxide film layer is The first hard mask layer etches the dielectric layer, and finally transfers the photolithography pattern structure to the dielectric layer or the dielectric layer and the substrate to complete the pattern transfer.

In another aspect, the present disclosure provides a super-resolution lithography structure, which is prepared according to the aforementioned method for preparing a super-resolution lithography structure.

(III) Beneficial effects

The super-resolution lithography structure, preparation method and pattern transfer method of the present disclosure adopt a reduced graphene oxide film layer as the first hard mask layer and a Si-containing anti-reflective coating as the second hard mask layer. The alternating arrangement of carbon layers and silicon layers with different etching ratios can achieve etching of the underlying layer, and the reduced graphene oxide film layer material contains a large number of aromatic ring C atoms, which has a high energy barrier and has a negative impact on the reaction. It has high impermeability to chemical gases and high etching resistance. The reduced graphene oxide film layer improves the etching selectivity ratio between the reduced graphene oxide film layer and the dielectric layer, and avoids problems such as pattern collapse and deformation caused by excessive aspect ratio in super-resolution lithography, thereby utilizing A thin hard mask layer can transfer the super-resolution photolithography pattern structure to the dielectric layer.

Description of drawings

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

Figure 2 schematically shows a flow chart of a method for pattern transfer of a super-resolution lithography structure according to an embodiment of the present disclosure;

Figure 3 schematically shows a flow chart of super-resolution lithography pattern transfer according to an embodiment of the present disclosure;

Figure 4 schematically shows a scanning electron microscope image during the transfer process of super-resolution lithography patterns according to Embodiment 1 of the present disclosure;

FIG. 5 schematically shows a cross-sectional view of the photolithography pattern structure obtained in Embodiment 1 of the present disclosure.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present disclosure more clear, the present disclosure will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the disclosure. The terms "comprising," "comprising," and the like, as used herein, indicate the presence of stated features, steps, operations, and/or components but do not exclude the presence or addition of one or more other features, steps, operations, or components.

In view of the problems that the existing SOC layer has a low etching selectivity ratio between the hard mask layer and the etched layer, and a thicker SOC layer can easily cause distortion and collapse of the pattern structure, the present disclosure aims to provide a A super-resolution photolithography structure, preparation method and photolithography method.

The present disclosure provides a method for preparing a super-resolution lithography structure. Please refer to Figure 1, which includes: S1, forming a dielectric layer 2 on the substrate 1; S2, depositing a graphene oxide layer on the dielectric layer 2; S3, The graphene oxide layer is baked and annealed to form a reduced graphene oxide film layer 3. The reduced graphene oxide film layer 3 serves as the first hard mask layer; S4, Si-containing anti-reflection is coated on the reduced graphene oxide film layer 3. Coating 4, the Si-containing anti-reflective coating 4 serves as the second hard mask layer; S5, sequentially deposit the metal layer 5 and coat the photosensitive layer 6 on the Si-containing anti-reflective coating 4 to obtain a super-resolution lithography structure.

In this disclosure, 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 are sequentially formed on a substrate 1, using The etching-resistant Reduced Graphene Oxide (RGO) material replaces the existing SOC material as the first hard mask layer, and the Si-containing anti-reflective coating serves as the second hard mask layer. The alternating arrangement of carbon layers and silicon layers with different etching ratios can achieve etching of the underlying layer. The molecular structure of graphene contains a large number of aromatic ring C atoms, has a high energy barrier, is highly impermeable to reactive gases, and has high etching resistance. Therefore, graphene is considered a good candidate material for barrier layers. However, in actual processes, it is difficult to obtain graphene films with uniform thickness on large-size substrates.

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 them 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, C-C bonds are more difficult to decompose than C-O 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.

Therefore, RGO as the first hard mask layer can significantly improve the etching ratio with the dielectric layer (the layer to be etched). Taking the etched layer as SiO ₂ as an example, the research results show that the etching ratio of SOC to SiO ₂ is 2:1, and the etching ratio of RGO to SiO ₂ is 3 to 8:1. Among them, the etching resistance of RGO increases with increasing annealing temperature. More importantly, RGO materials can avoid pattern collapse and deformation in super-resolution lithography. The preparation method of the SiBARC/RGO multilayer structure in the present disclosure is simple, does not require harsh conditions such as high temperature and high pressure, does not require high-cost equipment, and has low production cost.

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 SiO ₂ , SiN, poly-Si, Al ₂ O ₃ , and the thickness of the dielectric layer 2 is 10 to 500 nm.

Based on the above embodiment, S2 includes: S21, mix graphene oxide powder and solvent to form graphene oxide dispersion; S22, add graphene oxide dispersion droplets on the medium layer 2, and rotate at low speed to oxidize the graphene. The graphene dispersion spreads evenly; S23, high-speed rotation causes the solvent to evaporate to form a graphene oxide layer. Among them, the solvent in S21 includes one of deionized water, ethanol, tetrahydrofuran, isopropyl alcohol, ethanol, N, N-dimethylformamide, and N-methylpyrrolidone; the concentration of the graphene oxide dispersion is 1 ~10mg/mL.

GO dispersion is to mix a certain amount of GO powder prepared by the Hummers method with a solvent, and then configure it into a GO dispersion after ultrasound; the solvent mixed with GO is deionized water, ethanol, tetrahydrofuran, isopropyl alcohol, ethanol, N, N- One of dimethylformamide and N-methylpyrrolidone. Preferably, the concentration of the GO dispersion is 1 to 10 mg/mL. The concentration of the GO dispersion within this range has the technical effect of uniform dispersion, and it is easier to obtain a dense and uniform GO film. This is because too high a concentration of GO dispersion can easily cause GO to agglomerate in the solvent.

After preparing the GO dispersion, spin coating was used to deposit the GO film layer. Use a pipette to take the GO dispersion and drop it on the substrate to infiltrate it for a certain period of time, such as 1 to 2 minutes; rotate at a low rotation speed for a certain period of time, such as 1 to 2 minutes, in the range of 500rmp to 700rmp, to disperse the GO The liquid is evenly spread on the substrate; then it is rotated at a high rotation speed for a certain period of time, such as 0.5 to 1 minute, and the rotation speed is in the range of 1200rmp to 3000rmp, to speed up the evaporation of the solvent, so that the GO film can be evenly spread on the substrate to form an oxide film. Graphene layer.

Based on the above embodiments, S3 includes: baking and annealing the graphene oxide layer in an N ₂ or H ₂ atmosphere, the baking annealing temperature is 200 to 800°C, and the baking annealing time is 0.5 to 5 Hour.

The baking annealing step is performed at a temperature of 200°C to 800°C and lasts for 0.5 to 5 hours. Preferably, when the baking annealing step is performed at 200-500°C, the duration is preferably controlled at 3-5 hours; when the baking annealing step is performed at 500-800°C, the duration is preferably controlled at 30 minutes-2 hours, and can be selected between 30 minutes and 2 hours. Carry out under N ₂ , H ₂ and other atmospheres.

Based on the above embodiments, S3 includes: forming the reduced graphene oxide film layer 3 with a thickness of 1 to 50 nm.

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

Based on the above embodiments, the method of depositing the metal layer 5 on the Si-containing anti-reflective 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. .

Further, a coating method is used to form a Si-containing anti-reflective coating 4 on the RGO film layer. The Si-containing anti-reflective coating 4 acts as a hard mask and is provided on the RGO film layer because it is used in super-resolution lithography. Thin photoresist, and the thin photoresist has been exhausted before the RGO layer is completely etched; deposited on the above-mentioned Si-containing anti-reflective coating 4 by electron beam evaporation or magnetron sputtering deposition Metal layer 5, preferably, the material of metal layer 5 is one of Ag and Al; metal layer 5 is provided because photons drive the free electron coherent resonance on the surface of the metal conductor, thereby forming surface plasmons at the metal-dielectric interface. Polariton (SP), when the evanescent wave vector is the same as the SP wave vector, the two will resonate coherently, so that the evanescent wave carrying sub-wavelength spatial information is enhanced, so that super-resolution imaging can be achieved through regulation. Finally, A photosensitive layer 6 is formed on the metal layer 5 by a coating method to obtain a complete super-resolution photolithography structure.

Based on the above embodiment, after coating the photosensitive layer 6 in S5, it also includes: depositing a surface metal layer on the photosensitive layer 6 .

So far, the super-resolution lithography structure includes substrate 1, dielectric layer 2, reduced graphene oxide film layer 3, Si-containing anti-reflective coating 4, metal layer 5, photosensitive layer 6 and surface metal layer from bottom to top, where The metal layer 5, the photosensitive layer 6 and the surface metal layer form a resonant cavity imaging structure of metal/photoresist/metal, which is conducive to obtaining imaging lithography effects with higher resolution and contrast.

The present disclosure also provides a method for pattern transfer of a super-resolution lithography structure obtained according to the aforementioned preparation method of a super-resolution lithography structure. Please refer to Figures 2 to 3, including: S6, exposing and developing the photosensitive layer 6; Form a photolithography pattern structure; S7, etch the metal layer 5 and the Si-containing anti-reflective coating 4 in sequence, and remove the metal layer 5; S8, use the etched Si-containing anti-reflective coating under oxygen-containing plasma gas. Layer 4 serves as the second hard mask layer and uses 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, to obtain the etched reduced graphene oxide The olefin thin film layer 3 is the first hard mask layer to etch the dielectric layer 2, and finally transfers the photolithography pattern structure to the dielectric layer 2 or the dielectric layer 2 and the substrate 1 to complete the pattern transfer.

In this disclosure, after the dielectric layer 2, the reduced graphene oxide film layer 3, the Si-containing anti-reflective coating 4, the metal layer 5 and the photosensitive layer 6 are sequentially formed on the substrate 1, a photolithography pattern structure is first formed in the photosensitive layer 6, Then etch downwards layer by layer from top to bottom. The upper layer serves as the etching mask layer for the next layer. After the etching of the next layer is completed, the upper layer is removed and the etching continues downward. The photolithographic pattern structure in the photosensitive layer 6 is sequentially etched and transferred to the metal layer 5, Si-containing anti-reflective coating 4, reduced graphene oxide film layer 3 and dielectric layer 2 (or dielectric layer 2 and substrate 1), complete Graphical transfer. This method of etching transfer through a multi-layer structure has the advantages of simple preparation process, low production cost and high productivity.

Based on the above embodiments, the method of etching the metal layer 5 in S7 includes ion beam etching (IBE), and the etching gas is argon; the method of etching the Si-containing anti-reflective coating 4 includes One of ion beam etching (IBE), reactive ion etching (RIE) or inductive coupled plasma etching (Inductive Coupled Plasma, ICP). The etching gases use SF ₆ , CHF ₃ and Ar one or more of them.

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. Use IBE, RIE or ICP to etch the Si-containing anti-reflective coating 4 to transfer the photolithography pattern structure in the metal layer 5 to the SiBARC layer; the etching gas can be one or more of SF ₆ , CHF ₃ and Ar . After the etching of the SiBARC layer is completed, the metal layer 5 is removed by wet etching or mechanical stripping.

In S8, RIE or ICP is used to etch the RGO film layer under a plasma gas containing _O2 , and the photolithography pattern structure in the SiBARC layer is further transferred to the RGO layer. After the etching of the RGO layer is completed, the SiBARC layer is removed by wet etching. Preferably, the corrosion solution is an HF solution.

Based on the above embodiments, the method of etching the dielectric layer 2 in S9 includes one of ion beam etching, reactive ion etching and inductively coupled plasma etching. The etching gases are SF ₆ , CHF ₃ and Ar. one or more of them.

The material of the dielectric layer 2 includes SiO ₂ , SiN, poly-Si, Al ₂ O ₃ , and can be etched by RIE or ICP method. The etching gas can be one or more of SF ₆ , CHF ₃ and Ar, or a combination of CF ₄ /O ₂ and NF ₃ /O ₂ .

The present disclosure also provides a method for pattern transfer of a super-resolution lithography structure obtained according to the aforementioned method for preparing a super-resolution lithography structure, including:

S6, expose the photosensitive layer 6, remove the surface metal layer and then develop it to form a photolithography pattern structure; S7, etch the metal layer 5 and the Si-containing anti-reflective coating 4 in sequence, and remove the metal layer 5; S8, Under oxygen plasma gas, use the etched Si-containing anti-reflective coating 4 as the second hard mask layer and use 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. Si 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 transfer the photolithography pattern structure to the dielectric layer 2 or the dielectric layer 2 and Substrate 1, complete the graphics transfer.

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

The present disclosure also provides a super-resolution lithography structure, which is prepared according to the aforementioned method for preparing a super-resolution lithography structure.

The super-resolution lithography structure disclosed in the present invention has etching resistance and can be used not only in the manufacturing process of cutting-edge logic chips of super-resolution lithography, but also in the field of CMOS process at higher technology nodes.

The present disclosure will be further described below through specific embodiments. The above-mentioned super-resolution lithography structure, preparation method and pattern transfer method will be described in detail in the following examples. However, the following examples are only for illustrating the present disclosure, and the scope of the present disclosure is not limited thereto.

The preparation method of the super-resolution lithography structure and the pattern transfer method of the present disclosure, as shown in Figures 1 to 3, include performing the following steps in sequence:

Step 1: Prepare dielectric layer 2 on 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 SiO ₂ , SiN, poly-Si, and Al ₂ O ₃ , and the thickness of the dielectric layer 2 is 10 to 500 nm; which is equivalent to the above step S1.

Step 2: Configure GO dispersions of different concentrations to deposit a graphene oxide (GO) layer on the dielectric layer 2 using methods such as spin coating, spray coating, a combination of spin coating and spray coating, and printing methods; use different temperatures to treat the GO film layer A baking process is performed to form a reduced graphene oxide film layer 3, which serves as the first hard mask layer; this is equivalent to the above-mentioned steps S2 to S3.

Step 3: Use a coating method to form a Si-containing anti-reflective coating 4 on the reduced graphene oxide film layer 3. The Si-containing anti-reflective coating 4 serves as the second hard mask layer; equivalent to the above step S4;

Step 4: Deposit a metal layer 5 on the above-mentioned Si-containing anti-reflective coating 4 by electron beam evaporation or magnetron sputtering deposition. Preferably, the material of the metal layer 5 is one of Ag and Al;

Step 5: Use a coating method to form a photosensitive layer 6 on the above-mentioned metal layer 5. At this point, the preparation of the super-resolution photolithography structure is completed; which is equivalent to the above-mentioned step S5.

Step 6: Expose and develop the photosensitive layer 6 in the above-mentioned multi-layer film structure to obtain the required photolithographic pattern structure; equivalent to the above-mentioned step S6;

Step 7: Use IBE to etch the metal layer 5, and transfer the photolithography pattern structure in the photosensitive layer 6 to the metal layer 5; preferably, the etching gas is argon. Use IBE, RIE or ICP to etch the Si-containing anti-reflective coating 4, and transfer the photolithography pattern structure in the metal layer 5 to the Si-containing anti-reflective coating 4; the etching gas can be SF ₆ , CHF ₃ and Ar. One or more; then use wet etching and mechanical stripping to remove the metal layer 5; equivalent to the above step S7;

Step 8: Under a plasma gas containing _O2 , use RIE or ICP to etch and reduce the graphene oxide film layer 3, use the Si-containing anti-reflective coating 4 as the second hard mask layer, and use the Si-containing anti-reflective coating 4 as the second hard mask layer. The photolithographic pattern structure in 4 is transferred to the reduced graphene oxide film layer 3, and the silicon-containing anti-reflective coating 4 is removed; equivalent to the above step S8;

Step 9: Etch the underlying dielectric layer 2 or the dielectric layer 2 and the substrate 1 by using IBE, RIE or ICP, use the reduced graphene oxide film layer 3 as the first hard mask layer and 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; equivalent to the above step S9.

Based on the above steps 1 to 9, three specific embodiments are provided below.

Example 1:

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

Step 1: Deposit dielectric layer 2 on substrate 1 using electron beam evaporation. The dielectric layer 2 is SiO ₂ with a thickness of 200 nm;

Step 2: Spin-coat a graphene oxide film at a rotation speed of 1500rmp, a spin-coating time of 30s, repeat 10 times, and bake and anneal at 240°C for 3 hours to form a 30nm-thick reduced graphene oxide (RGO); the GO used The concentration of the dispersion is 5mg/mL, and the solvent is ethanol; among them, you can first use a pipette to take GO dispersion droplets and infiltrate them on the substrate for a certain period of time, then rotate at a lower speed of 500 to 700rmp for a certain period of time, and then perform the above high-speed rotation ;

Step 3: Use the spin coating process to prepare the silicon-containing anti-reflective coating 4, the rotation speed is 2000 rpm, the spin coating time is 30 seconds, bake on a hot plate at 210°C for 2 minutes, the thickness of the silicon-containing anti-reflective coating 4 is 30 nm;

Step 4: Use magnetron sputtering to deposit a metal layer 5 with a thickness of 40nm. The metal layer 5 is an Ag layer, and the DC power is 50W;

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

Step 6: Expose and develop the photosensitive layer 6. The exposure dose is 70mJ to obtain a grating structure with a half period of 200nm.

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

Step 8: The photolithographic pattern structure is further transferred to the silicon-containing anti-reflective coating 4 by RIE etching, and the etching is performed using 20 W of RF power and 20 sccm of CHF ₃ gas;

Step 9: Prepare a 1:1 _HNO3 :DI aqueous solution, soak the above sample for 30s, then rinse and blow dry with _N2 to remove the Ag layer;

Step 10: Use RIE etching to further transfer the photolithographic pattern structure to the reduced graphene oxide film layer 3, use 20W radio frequency power and 20 sccm O ₂ gas for etching; use HF solution to remove the silicon-containing anti-reflective coating 4;

Step 11: Use RIE etching to further transfer the photolithography pattern structure to the SiO ₂ layer, and use 20W radio frequency power and 20 sccm CHF ₃ gas for etching.

Figure 4 is an electron microscope image of the grating structure in the photosensitive layer 6 in this embodiment being transferred to the silicon-containing anti-reflective coating 4, the reduced graphene oxide film layer 3 and the SiO ₂ layer completely without distortion or deformation. Figure 5 is a cross-sectional view of the photolithography pattern structure obtained in this embodiment.

The super-resolution photolithography structure, preparation method and pattern transfer method provided in this embodiment are based on the highly etching-resistant RGO film layer and can use the 30nm thick RGO layer to transfer the grating pattern etching to the 126nm SiO ₂ layer ( As shown in Figure 5), the etching ratio of RGO and _SiO2 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 the ability to shorten the process time.

Example 2:

The preparation steps of the super-resolution lithography structure and its pattern formation in this embodiment are as follows:

Step 1: Deposit dielectric layer 2 on substrate 1 using electron beam evaporation. The dielectric layer 2 is SiO ₂ with a thickness of 100 nm;

Step 2: Spin-coat a graphene oxide film at a rotation speed of 2000 rpm and a spin-coating time of 30 seconds. Repeat 6 times. Bake and anneal at 600°C for 2 hours to form a 15nm-thick reduced graphene oxide (RGO). The GO used The concentration of the dispersion is 8 mg/mL, and the solvent is N, N-dimethylformamide; among them, you can first use a pipette to take GO dispersion droplets and infiltrate them on the substrate for a certain period of time, and then rotate at a low speed of 500 to 700 rpm. After a certain period of time, the above high-speed rotation is performed;

Step 3: Use the spin coating process to prepare the silicon-containing anti-reflective coating 4, the rotation speed is 4000 rpm, the spin coating time is 30 seconds, bake on a hot plate at 210°C for 2 minutes, the thickness of the silicon-containing anti-reflective coating 4 is 20 nm;

Step 4: Use magnetron sputtering to deposit the underlying metal layer 5 with a thickness of 40nm. The metal layer 5 is an Ag layer, and the DC power is 50W;

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

Step 6: Expose and develop the photosensitive layer 6. The exposure dose is 80mJ to obtain a grating structure with a half period of 120nm.

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

Step 8: The photolithographic pattern structure is further transferred to the silicon-containing anti-reflective coating 4 through RIE etching, and etching is performed using 20W radio frequency power and 20 sccm CHF ₃ gas;

Step 9: Prepare 1:1 _HNO3 :DI aqueous solution, soak the above sample for 30s, then rinse and blow dry with _N2 to remove the Ag layer;

Step 10: Use RIE etching to further transfer the photolithographic pattern structure to the reduced graphene oxide film layer 3, use 20W radio frequency power and 20 sccm O ₂ gas for etching; use HF solution to remove the silicon-containing anti-reflective coating 4;

Step 11: Use RIE etching to further transfer the photolithography pattern structure to the SiO ₂ layer, and use 20W radio frequency power and 20 sccm CHF ₃ gas for etching.

This embodiment is based on the RGO film layer with high etching resistance. It can use the 15nm thick RGO layer to transfer the grating pattern etching to the 100nm SiO ₂ layer. The etching ratio of RGO to SiO ₂ reaches 6:1.

Example 3:

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

Step 1: Deposit dielectric layer 2 on substrate 1 using electron beam evaporation. The dielectric layer 2 is SiO ₂ with a thickness of 200 nm;

Step 2: Spin-coat a graphene oxide film at a rotation speed of 1500rmp, a spin-coating time of 30s, repeat 15 times, and bake and anneal at 600°C for 2 hours to form a 30nm-thick reduced graphene oxide (RGO); the GO used The concentration of the dispersion is 3 mg/mL, and the solvent is deionized water; among them, you can first use a pipette to take GO dispersion droplets and infiltrate them on the substrate for a certain period of time, then rotate at a low speed of 500 to 700 rpm for a certain period of time, and then perform the above high-speed of rotation;

Step 3: Use the spin coating process to prepare the silicon-containing anti-reflective coating 4, the rotation speed is 2000 rpm, the spin coating time is 30 seconds, bake on a hot plate at 210°C for 2 minutes, the thickness of the silicon-containing anti-reflective coating 4 is 30 nm;

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;

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

Step 6: Use vacuum evaporation to deposit a surface metal layer with a thickness of 12 nm. The surface metal layer is Ag, and the deposition rate is 0.3 nm/s. At this point, the preparation of the resonant cavity structure for super-resolution lithography is completed. The resonant cavity imaging structure using metal/photoresist/metal 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 better results. High resolution and contrast SP imaging lithography effect.

Step 7: Expose the photosensitive layer 6. The exposure dose is 200mJ. HNO ₃ removes the surface Ag and develops it to obtain a through-hole structure with a diameter of 65nm.

Step 8: Use IBE etching to transfer the photolithography pattern structure in the photosensitive layer 6 to the Ag layer. The selected ion beam current is 260mA and the incident angle is 10° (the angle between the normal line of the substrate and the ion beam current). Use 14 sccm Ar gas for etching; remove the photosensitive layer 6;

Step 9: The photolithographic pattern structure is further transferred to the silicon-containing anti-reflective coating 4 through RIE etching, using 20W radio frequency power and 20 sccm CHF ₃ gas for etching;

Step 10: Prepare a 1:1 HNO3: _DI aqueous solution, soak the above sample for 30s, then rinse and blow dry with _N2 to remove the Ag layer;

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;

Step 12: Use RIE etching to further transfer the photolithography pattern structure to the SiO ₂ layer, and use 20W radio frequency power and 20 sccm CHF ₃ gas for etching.

This embodiment is based on the RGO film layer with high etching resistance, which can achieve super-resolution lithography with a half period of 65 nm, and can further transfer the pattern to the RGO film layer and SiO ₂ dielectric layer. The etching selection of RGO and SiO ₂ The ratio reaches 6:1.

The etching transfer process provided by this photolithography can not only successfully transfer the photolithography 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 finer size The pattern avoids problems such as collapse and deformation of the C-containing layer when etching the dielectric layer, which affects the etching results and avoids deterioration of device performance.

The above-mentioned specific embodiments further describe the purpose, technical solutions and beneficial effects of the present disclosure in detail. It should be understood that the above-mentioned are only specific embodiments of the present disclosure and are not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of this disclosure shall be included in the protection scope of this disclosure.

Claims (12)

1. A method for preparing a super-resolution lithography structure, which is characterized by including:

   S1, forming a dielectric layer (2) on the substrate (1);

   S2, deposit a graphene oxide layer on the dielectric layer (2);

   S3, perform baking and annealing on the graphene oxide layer to form a reduced graphene oxide film layer (3), and the reduced graphene oxide film layer (3) serves as the first hard mask layer;

   S4, apply a Si-containing anti-reflective coating (4) on the reduced graphene oxide film layer (3), and the Si-containing anti-reflective coating (4) serves as the second hard mask layer;

   S5, sequentially deposit the metal layer (5) and coat the photosensitive layer (6) on the Si-containing anti-reflective coating (4) to obtain a super-resolution lithography structure.
2. The method for preparing a super-resolution lithography structure according to claim 1, wherein the S2 includes:

   S21, mix graphene oxide powder and solvent to form graphene oxide dispersion;

   S22, add the graphene oxide dispersion liquid dropwise on the medium layer (2), and rotate at a low speed to spread the graphene oxide dispersion liquid evenly;

   S23, rotate at high speed to evaporate the solvent to form a graphene oxide layer.
3. The method for preparing a super-resolution lithography structure according to claim 2, characterized in that the solvent in S21 comprises 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.
4. The method for preparing a super-resolution lithography structure according to claim 1, wherein said S3 includes:

   The graphene oxide layer is baked and annealed. The baking annealing is performed in an N2 or H2 atmosphere. The baking annealing temperature is 200-800°C, and the baking annealing time is 0.5-5 hours. .
5. The method for preparing a super-resolution lithography structure according to claim 4, wherein the S3 further includes:

   The thickness of the reduced graphene oxide film layer (3) is 1 to 50 nm.
6. The method for preparing a super-resolution lithography structure according to claim 1, wherein the method of depositing the metal layer (5) on the Si-containing anti-reflective 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.
7. The method for preparing a super-resolution lithography structure according to claim 1, characterized in that after the S5 coating the photosensitive layer (6), it further includes:

   A surface metal layer is deposited on the photosensitive layer (6).
8. A method for pattern transfer of a super-resolution lithography structure obtained according to the method for preparing a super-resolution lithography structure according to any one of claims 1 to 6, characterized in that it includes:

   S6, expose and develop the photosensitive layer (6) to form a photolithography pattern structure;

   S7, sequentially etching the metal layer (5) and the Si-containing anti-reflective coating (4), and removing the metal layer (5);

   S8, under oxygen-containing plasma gas, use the etched Si-containing anti-reflective coating (4) as the second hard mask layer and use reactive ion etching or inductively coupled plasma to etch the reduced graphite oxide ene film layer (3), and remove 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.
9. The method of pattern transfer according to claim 8, characterized in that the method of etching the metal layer (5) in S7 includes ion beam etching, and the etching gas uses argon;

   The method of etching the Si-containing anti-reflective coating (4) includes one of ion beam etching, reactive ion etching and inductively coupled plasma etching. The etching gases use SF ₆ , CHF ₃ and Ar. one or more of them.
10. The method of pattern transfer according to claim 8, characterized in that the method of etching the dielectric layer (2) in S9 includes one of ion beam etching, reactive ion etching and inductively coupled plasma etching. The etching gas uses one or more of SF ₆ , CHF ₃ and Ar.
11. A method for pattern transfer using a super-resolution lithography structure obtained by the method for preparing a super-resolution lithography structure according to claim 7, characterized in that it comprises:

    S6, expose the photosensitive layer (6), remove the surface metal layer and then develop it to form a photolithography pattern structure;

    S7, sequentially etching the metal layer (5) and the Si-containing anti-reflective coating (4), and removing the metal layer (5);

    S8, under oxygen-containing plasma gas, use the etched Si-containing anti-reflective coating (4) as the second hard mask layer and use reactive ion etching or inductively coupled plasma to etch the reduced graphite oxide ene film layer (3), and remove the Si-containing anti-reflective coating (4);

    S9, use the etched reduced graphene oxide film layer (3) as the first hard mask layer to etch the dielectric layer (2), and finally transfer the photolithography pattern structure to the dielectric layer (2) Or the dielectric layer (2) and the substrate (1) complete the pattern transfer.
12. 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 7.

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