A directed self-assembly patterning substrate and a method of forming a pattern thereof

Abstract

The present application belongs to the field of semiconductor manufacturing, and discloses a guided self-assembly patterning substrate and a method for forming a pattern. In the method, a neutral layer is first formed on a substrate, then a guiding template with different surface properties and / or pattern differences in different regions is formed on the neutral layer, and then a block copolymer film is formed on the guiding template. The film induces micro-phase separation of the block copolymer under annealing treatment, and self-assembles to form a phase separation polymer layer with two or more phase patterns. At least one phase region of the polymer layer is selectively etched to form a mask layer with two or more patterns such as close-packed holes and lines. Finally, the pattern of the mask layer is transferred to the substrate. The present application uses a method of synchronously generating two or more patterns on the same substrate by using a block copolymer, which can reduce the use of copolymer material types and process steps, and reduce production costs, and has wide application in the field of advanced node manufacturing of integrated circuits.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor manufacturing, and specifically relates to a guided self-assembly patterned substrate and a method for forming patterns thereon. Background Technology

[0002] The integrated circuit industry is a core support for information technology and a strategic, fundamental, and pioneering industry driving national economic development. Photolithography technology is crucial for integrated circuit manufacturing. With the development of artificial intelligence, the demand for computing power in chips is gradually increasing. How to achieve high-resolution pattern preparation for high-end chip manufacturing is a pressing problem in the integrated circuit field. Directed self-assembly (DSA) patterning technology is a method that utilizes copolymers to undergo microphase separation on a semiconductor substrate and self-assembles under the guidance of an external pattern to form a high-resolution pattern. The high-resolution pattern is then transferred to the substrate, thus patterning the semiconductor substrate. This technology offers high resolution, high throughput, high compatibility, and low cost, making it one of the key alternatives for next-generation integrated circuit photolithography technology. The pattern resolution of DSA technology is determined by its degree of polymerization and interaction parameters, and high-resolution pattern preparation can be achieved by controlling the molecular weight.

[0003] Furthermore, a key factor in DSA technology is the guidance method, primarily consisting of two main approaches: chemical epitaxy and physical epitaxy. The former utilizes the different chemical properties of the substrate interface to induce copolymer self-assembly and form patterns. The latter uses three-dimensional physical trenches or perforated templates to constrain copolymer self-assembly, forming ordered patterns within a confined space. Currently, a single DSA process on a single substrate typically only creates one type of pattern (e.g., all lines or all holes). However, logic chip patterns are more complex. If both lines (for interconnects) and holes (for vias or contact holes) need to be fabricated simultaneously in different functional areas of the chip, existing technologies are extremely cumbersome. This usually requires two or more independent photolithography and DSA processes to define the line and hole regions separately. This necessitates two or more different photomasks, leading to high costs, complex processes, and extremely difficult alignment between the two patterns. Moreover, fabricating lines and densely packed holes requires two different copolymers, and the compatibility of coating processes for different film layers must be considered.

[0004] Therefore, the industry urgently needs a solution that can simplify the process, reduce costs, and achieve simultaneous integration of multiple graphics in a single DSA process. Summary of the Invention

[0005] In view of the problems of patterning based on DSA in the prior art, the present invention will provide a guided self-assembly patterned substrate and a method for forming patterns thereon.

[0006] To achieve the above objectives, the following technical solutions are specifically included: In a first aspect, the present invention provides a method for forming a pattern on a substrate, comprising the following steps: S1. A neutral layer is formed on at least one surface of the substrate; S2. A guide template is formed on the neutral layer, and the guide template is patterned and / or surface treated to form a guide template with a periodic pattern on the neutral layer, wherein the guide template includes at least two regions with different surface properties and / or topological patterns. S3. A block copolymer solution is coated onto the guiding template to form a block copolymer film; the volume fraction of at least one block of the block copolymer in the block copolymer solution is within the range of phase regions capable of forming at least two different morphologies; S4. Anneal the block copolymer film to form a phase-separated polymer layer, the phase-separated polymer layer comprising at least two phase regions formed by the separation of the block copolymer in the block copolymer film; at least one phase region exhibits a periodic arrangement and has at least two different morphologies; S5. Etch at least one phase region of the phase-separated polymer layer and its corresponding neutral layer to obtain a mask layer with at least two different patterns. S6. The pattern of the mask layer is transferred to the substrate by etching.

[0007] In the method for forming a pattern on a substrate according to the present invention, a neutral layer is first prepared on the substrate surface to facilitate the subsequent induction of microphase separation by the block copolymer, resulting in a phase orientation perpendicular to the substrate. A photoresist layer is then formed on the neutral layer. A guide template is obtained by patterning and / or surface treatment of the photoresist layer. The patterning or surface treatment process differentiates the surface properties and / or topological structures of different regions of the obtained guide template. A block copolymer film is then coated on the guide template. During annealing, the high degree of dependence of the block copolymer in the film on initial conditions near the thermodynamic phase transition is utilized. Sensitivity: Block copolymers in thin films, based on differences in surface chemical properties and / or topological structures in different regions of the guiding template, induce microphase separation in the block copolymers, forming phase regions with different morphologies in the regions with different surface chemical properties and / or topological structures. The phase regions with different morphologies form the basis for different patterns. Then, at least one phase region and its corresponding neutral layer in the phase-separated polymer layer are selectively removed to form patterns such as grooves or holes at the corresponding positions, obtaining a substrate mask layer with more than two patterns. Finally, the pattern of the mask layer is transferred to the substrate by etching. In the method of this invention, the surface properties or topological structures of different regions on the guiding template differ. When guiding the microphase separation of the block copolymer, at least one phase region on the phase-separated polymer layer will have two or more morphologies. Therefore, after etching away at least one phase region, different patterns will be formed in different regions on the mask layer. Thus, the method of this invention can simultaneously generate at least two functionally distinct, uniform, and periodic large-scale nanopatterns (such as lines and holes) in different regions of the substrate in a single process, greatly simplifying the process flow and the use of different types of materials, and reducing the number of photomasks used and the cost of photolithography / DSA processes. Preferably, in step S1, the neutral layer includes at least one of random copolymers and random copolymers with hydroxyl groups at the ends. The random copolymers include ArB-type and / or ArBrC-type random copolymers. The monomer molecules in the random copolymers and the random copolymers with hydroxyl groups at the ends are independently selected from at least one of polystyrene (PS), polymethyl methacrylate (PMMA), poly(β-cinnamoxyethyl methacrylate) (PMPA), or polyglycidyl methacrylate (PGMA). The purpose of the neutral layer is to induce the subsequent self-assembly of block copolymers to form a vertically oriented phase structure.

[0008] The copolymers mentioned in this article include ArB type and / or ArBrC type copolymers. In copolymers (including random copolymers or block copolymers), "A", "B", and "C" represent monomer A molecular chain segments (or A blocks), monomer B molecular chain segments (or B blocks), and monomer C molecular chain segments (or C blocks), respectively. "r" indicates that monomer A molecular chain segments and monomer B molecular chain segments are randomly arranged along the copolymer backbone. "b" indicates that monomer A molecular chain segments and monomer B molecular chain segments are homopolymerized within their respective molecular chain segments and are connected only at the ends of the two monomer molecular chain segments.

[0009] Preferably, in the ArB type random copolymer, the molar percentage of monomer molecule A is 50%-80%, and the molar percentage of monomer molecule B is 20%-50%.

[0010] More preferably, the random copolymer includes at least one of PS-r-PMMA and PS-r-PMMA-r-PGMA, wherein the percentage molar content of the PS component is 50%-80%, the percentage molar content of the PMMA component is 20%-50%, and the percentage molar content of the PGMA component is 0-5%.

[0011] More preferably, in step S1, the random copolymer containing hydroxyl groups at the end includes hydroxyl-terminated PS-r-PMMA.

[0012] Preferably, in step S1, the specific steps for forming the neutral layer include: coating a raw material dispersion of the neutral layer onto at least one surface of the substrate, followed by drying and / or curing to obtain the neutral layer. The mass concentration of the solution of random copolymers and / or random copolymers with terminal hydroxyl groups in the raw material dispersion is 0.1%-2%. Preferably, the coating method includes at least one of spin coating, blade coating, spray coating, LB coating, or drop coating.

[0013] More preferably, in the spin coating method, the spin coating speed is 500-2000 rpm and the spin coating time is 5-120 s.

[0014] Preferably, in step S1, the thickness of the neutral layer is 1-20 nm.

[0015] Preferably, in step S1, the thickness of the substrate is 500-1000 μm.

[0016] Preferably, in step S1, the substrate comprises a silicon-based substrate.

[0017] This article discusses ways in which the surface properties of a guide template differ, including differences in surface chemical and / or physical properties caused by variations in the composition of different materials, and / or differences in surface chemical and / or physical properties caused by surface treatment processes.

[0018] Preferably, in step S2, the guiding template includes a photoresist layer, the patterning process includes exposure, development, and drying, and the surface treatment includes surface treatment of the photoresist layer using electron beam, ion beam, or extreme ultraviolet light. The above-described method prepares the pattern of the guiding template, resulting in different chemical contrasts between the guiding template and the substrate. For example, the first region has a strong affinity for blocks, the second region has a strong affinity for PMMA blocks, or is a neutral surface. The above surface treatment defines surfaces and patterns with different surface energies or chemical affinities in different regions of the guiding template. The guiding template can be of two or more types, inducing the simultaneous generation of multiple patterns while changing the surface properties of each region. The patterning of the guiding template can be achieved through standard photolithography processes, easily integrated into existing process flows; its mechanism of action is diverse, and can be chemical patterns (different surface energies), topological patterns (grooves of different heights or shapes), or a combination of both.

[0019] Preferably, in step S2, the regions with at least two different surface properties and / or topological patterns include at least two regions with different surface properties, and / or regions with different topological patterns, wherein the different topological patterns include grooves and / or protrusions with different heights and / or shapes, and more specifically may include at least one of trenches, columns, and holes.

[0020] More preferably, the surface property includes surface energy.

[0021] More preferably, the surface properties include the water contact angle.

[0022] More preferably, the guide template includes at least two regions with different surface properties, and the water contact angle between any two regions with different surface properties differs by more than 5°, and more preferably by 6° to 15°.

[0023] Preferably, in step S2, the guide template includes at least one of a bar pattern and a cylindrical pattern.

[0024] Preferably, in step S2, the guide template includes at least two regions among a first region, a second region, and a third region with different surface properties and / or topological patterns. The first region includes a periodic bar pattern, the second region includes a periodic cylindrical pattern, and the surface properties of the third region are different from those of the first region and / or the second region.

[0025] Preferably, in step S3, the mass concentration of the block copolymer solution is 0.5%-3%.

[0026] Preferably, in step S3, the block copolymer in the block copolymer solution includes a diblock copolymer or a triblock copolymer.

[0027] Preferably, in step S3, the block copolymer in the block copolymer solution includes at least one of polystyrene-b-polymethyl methacrylate (PS-b-PMMA), polystyrene-b-polymethyl methacrylate (PS-b-PMA), polystyrene-b-polyisoprene (PS-b-PI), polystyrene-b-polylactic acid (PS-b-PLA), polystyrene-b-polydimethylsiloxane (PS-b-PDMS), polystyrene-b-polytrimethylene carbonate (PS-b-PTMC), polystyrene-b-polyvinyl acetate (PS-b-PVAc), polystyrene-b-polyvinylpyridine (PS-b-PVP), and polystyrene-b-poly(methyl methacrylate-r-glycidyl methacrylate derivative) (PS-bP(MMA-r-GMA derivative)).

[0028] Preferably, in step S3, the volume fraction of at least one block of the block copolymer in the block copolymer solution is within a range capable of forming at least two different phase regions. Based on the total volume of the block copolymer, the volume fraction of at least one block in the block copolymer is 55%-75%, more preferably 58%-70%. The volume fraction of at least one block of the block copolymer satisfies the requirement that it can form at least two different phase diagram boundary regions under equilibrium conditions, enabling the block to form at least two phase regions with different phase morphologies during microphase separation.

[0029] Preferably, in step S3, when the block copolymer in the block copolymer solution is polystyrene-b-polymethyl methacrylate (PS-b-PMMA), the volume fraction of polystyrene blocks in the polystyrene-b-polymethyl methacrylate is 58%-70%, and the volume fraction of polymethyl methacrylate blocks is 30%-42%. The self-assembly morphology of the copolymer is affected by its volume fraction. For example, with polystyrene-block-polymethyl methacrylate (PS-b-PMMA), by adjusting this parameter, layered, columnar, and spherical morphologies can be formed. Then, selective etching can be used to remove one phase to achieve the preparation of lines or close-packed hole patterns. When the block copolymer is polystyrene-b-polymethyl methacrylate (PS-b-PMMA), the volume fraction ratio of PS blocks to PMMA blocks falls within the aforementioned range, placing it near the "layered-columnar" phase transition point. This allows the copolymer to independently form phase diagram boundary regions between layered and columnar phases in equilibrium, making the final microphase separation morphology extremely sensitive to external boundary conditions (such as the surface properties and topology of the guiding template). This allows for control over the final formation of layered or columnar structures through local guidance. Therefore, given the aforementioned block copolymer volume fraction, the guiding template needs to provide an initial driving force for the block copolymer in different regions to achieve its most easily formed stable state through precisely defined local surface chemical differences. This process conforms to thermodynamic principles, resulting in low pattern defects and high stability.

[0030] Preferably, the block copolymer comprises a linear, cyclic, star-shaped, or bottle-brush-shaped block copolymer. Preferably, in step S4, the thickness of the phase-separated polymer layer is 10-100 nm.

[0031] Preferably, in step S4, the morphology is selected from at least one of layered phase, columnar phase, globular phase, and combinations thereof.

[0032] Preferably, in step S4, the annealing process includes at least one of thermal annealing, solvent annealing, laser annealing, and ultraviolet annealing.

[0033] Preferably, the temperature of the thermal annealing is 200-300℃, and the thermal annealing time is 1-60 min. In the ultraviolet annealing, the wavelength of the ultraviolet light is 200-400 nm, and the annealing time is 10-60 min.

[0034] Preferably, in step S4, the phase region exhibits an orientation structure perpendicular to the substrate.

[0035] Preferably, in step S4, when at least one phase region exhibits a periodic arrangement, the period of the phase region is L0, and the period of the guiding template in step S2 is L... s The following relationship is satisfied: Ls >L0, more preferably, L s =n×L0, where n is ≥1, or more specifically, n=2-5. More specifically, L0 is 10-50 nm, L... s It is 20-300nm.

[0036] Preferably, the phase-separated polymer layer comprises two first phase regions and a second phase region formed by the separation of block copolymers in the block copolymer film; the first phase region comprises a PS phase region, the second phase region comprises a PMMA phase region, the second phase region exhibits a periodic arrangement and has at least two different morphologies, and the second phase region includes layered phase and columnar phase morphologies.

[0037] More specifically, in step S2, the guide template includes at least two regions among a first region, a second region, and a third region with different surface properties and / or topological patterns. The first region includes a periodic strip pattern, the second region includes a periodic cylindrical pattern, and the surface properties of the third region differ from those of the first region and / or the second region are included in the first pattern region of the guide template. Meanwhile, in step S4, the phase-separated polymer layer on the first region includes a first phase region and a second phase region, the second phase region having a periodic and layered phase morphology. The phase-separated polymer layer on the second region includes a first phase region and a second phase region, the second phase region having a periodic and columnar phase morphology.

[0038] The periodic strip pattern regions on the guide template preferentially induce the assembly of block copolymers to form a layered periodic nanophase structure; the periodic cylindrical pattern regions on the guide template preferentially induce the assembly of block copolymers to form a columnar periodic nanophase structure.

[0039] More preferably, the water contact angle of the first region and the second region are each independently selected from 80° to 90°, and more preferably 85°-88°.

[0040] More preferably, the water contact angle of the third region is smaller than that of the first region and / or the second region; more specifically, the water contact angle of the third region is 70-80°.

[0041] Preferably, in step S5, the etching is performed using plasma etching, and the plasma includes a mixed etching gas of O2 and Ar, with the volume percentages of O2 and Ar distributed as 80%-95% and 5%-20%, respectively.

[0042] In phase-separated polymer layers, the sizes of different phase regions often reach the nanoscale, also known as nanodomains. When using plasma etching with a mixed etching gas including O2 and Ar, different phase regions exhibit varying resistance to plasma etching, making it easier to remove a phase region that is not resistant to plasma etching. For example, when PS and PMMA phase regions are present, the PS phase region has higher corrosion resistance. Plasma etching with the mixed O2 and Ar etching gas more easily removes the PMMA phase region, forming grooves or holes at the PMMA phase region location to expose the neutral layer and / or substrate beneath the phase-separated polymer layer. The remaining PS phase region still covers the neutral layer, preventing subsequent etching processes from affecting the substrate beneath these regions.

[0043] Preferably, in step S6, the etching includes dry etching, the dry etching includes reactive ion etching, and the gas used in the reactive ion etching includes CHF3.

[0044] Preferably, the method further includes step S7: removing the mask layer, wherein the method of removing the mask layer includes oxygen plasma etching.

[0045] In a second aspect, the present invention provides a patterned substrate, which is obtained by the method of forming a pattern on the substrate.

[0046] Preferably, the patterned substrate includes at least one of periodic holes and grooves, wherein the size of the holes is 1-100 nm, more preferably 10-30 nm; the spacing between adjacent holes is 10-100 nm, more preferably 20-40 nm; and the size of the grooves is 10-50 nm.

[0047] Compared to existing technologies, this invention offers the following advantages: In the method of this invention, a neutral layer and guide templates with different surface properties and / or pattern differences in different regions are first formed sequentially on a substrate. Then, a block copolymer film is formed on the guide template. Under annealing, the block copolymer undergoes microphase separation, self-assembling to form a phase-separated polymer layer with two or more phase morphologies. At least one phase region of the polymer layer is then selectively etched away to form a mask layer with two or more patterns, such as closely spaced holes and lines. Finally, the pattern of the mask layer is transferred to the substrate. This invention utilizes a method for simultaneously generating two or more patterns on the same substrate using block copolymers, which reduces the types of copolymer materials used and the number of process steps, lowering production costs and having wide applications in the field of advanced node manufacturing of integrated circuits. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the process flow for patterning on the substrate in Example 1; Figure 2 This is a schematic diagram of the substrate structure containing the guiding template in Example 1; Figure 3 This is a schematic diagram of the substrate structure containing the phase-separated polymer layer in Example 1; Figure 4 This is a result of scanning electron microscopy testing of the line pattern on the mask layer in Example 1; Figure 5 This is a result of scanning electron microscopy testing of the hole pattern on the mask layer in Example 1; Figure 6 This is a schematic diagram of the substrate structure containing the guiding template (left) and the phase-separated polymer layer (right) in Examples 8-9; Figure descriptions: 101, substrate; 102, neutral layer; 103, photoresist layer; 104, phase-separated polymer layer; 105, PS phase region. Detailed Implementation

[0049] To better illustrate the purpose, technical solution, and advantages of this invention, specific embodiments will be used to further explain the invention below. Unless otherwise specified, the test methods used in the embodiments and / or comparative examples are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available.

[0050] The PS-r-PMMA-OH, PS-r-PMMA-r-PGMA, PS-r-PMMA-r-PMPA, same-arm star-shaped block copolymers, and bottle brush copolymers used below are all commercially available.

[0051] Example 1 A method for fabricating patterns on a substrate, the structural schematic diagram of which is shown below. Figure 1-3 As shown, it includes the following steps: S1. Using propylene glycol methyl ether acetate (PGMEA) as solvent, a PS-r-PMMA-OH solution (purchased from polymer source) containing hydroxyl groups was prepared, wherein the volume fractions of PS and PMMA components in the PS-r-PMMA-OH solution were 75% and 25%, respectively. The PS-r-PMMA-OH solution was spin-coated onto a silicon wafer substrate (101) with a length of 2 cm, a width of 2 cm, and a thickness of 500 μm. During spin-coating, the substrate was first rotated at 500 rpm for 5 s, and then at 2000 rpm for 1 min to obtain a neutral layer (102).

[0052] S2. A 50nm PMMA photoresist layer is spin-coated onto the neutral layer. Using an electron beam lithography machine, exposure is performed through a photomask with pre-designed nanoline and nanocircular patterns. After exposure, development and baking are performed. The exposed areas in the photoresist layer are removed, forming grooves and exposing the neutral layer. The unexposed areas of the photoresist are retained, forming protrusions. Overall, periodic nanoscale line patterns are formed on corresponding area A of the substrate, and periodic nanoscale cylindrical patterns are formed on corresponding area B of the substrate, thus obtaining the guide template. Figure 2 The period of the graph in region A is L. s =54nm, the pattern period L on region B s =62nm. Simultaneously, the water contact angles of regions A and B on the substrate were tested, and the results showed that the water contact angles of both regions A and B were 85°.

[0053] S3. Using PGMEA as a solvent, a PS-b-PMMA solution was prepared, wherein the volume fractions of PS blocks and PMMA blocks in the PS-b-PMMA solution were 68% and 32%, respectively, and the mass percentage of PS-b-PMMA in the PS-b-PMMA solution was 1.5%. The PS-b-PMMA solution was spin-coated onto a guide template to form a film. The spin-coating conditions were as follows: first, spin at 500 rpm for 5 seconds, and then spin at 2000 rpm for 1 minute to obtain a substrate with a film thickness of 40 nm.

[0054] S4. The substrate containing the thin film is annealed in vacuum at 250°C for 30 minutes to induce microphase separation of the PS-b-PMMA block copolymer and guide its self-assembly to form a phase-separated polymer layer with a thickness of 37 nm. In this guiding template, regions A and B both contain exposed neutral layers and photoresist layers. The surface properties of the exposed neutral layer and photoresist layer differ due to differences in their material composition. Simultaneously, the pattern morphology differs between regions A and B, which is a difference in topology. During annealing, the final morphology of the microphase separation of the block copolymer is extremely sensitive to external boundary conditions (such as the surface properties and topology of the guiding template). Because the guiding template in this embodiment not only has non-uniform surface properties in regions A and B, but also exhibits differences in topology between regions A and B, it can serve as a guiding template for the block copolymer to guide the formation of different phase structures during microphase separation. The PS and PMMA blocks exhibit microphase separation, forming PS and PMMA phase regions respectively. Both PS and PMMA phase regions show an orientation perpendicular to the substrate. The PMMA phase regions are periodically arranged and possess both layered and columnar phase morphologies. More specifically, a schematic diagram of the separated polymer layer structure in this embodiment is shown below. Figure 3As shown, in region A, the PMMA phase region exhibits a layered phase morphology with periodic stripes, while in region B, the PMMA phase region exhibits a periodic cylindrical phase morphology. The period L0 of the PMMA phase region in region A is 27 nm, and the period L0 of the PMMA phase region in region B is 31 nm; L in step S2 s The relationship between L0 and L0 is: L s =n×L0, n=2.

[0055] S5. Using a mixture of O2 (90% by volume) and Ar (10% by volume) as the plasma etching gas, the PMMA phase region and the corresponding neutral layer in the separated polymer layer are selectively etched away to expose the underlying substrate. This results in periodic grooves and holes forming at the PMMA phase regions in regions A and B, respectively. The walls surrounding the grooves and holes form the PS phase region to obtain a patterned mask layer made of the remaining PS. This mask layer has periodic line patterns and hole patterns in regions A and B, respectively.

[0056] The mask layer was tested using scanning electron microscopy, and the test results are as follows: Figure 4-5 As shown, where, Figure 4 The area is a periodic hole pattern in region B, with an average hole diameter of 12 nm and an average spacing of 31 nm between adjacent holes. Figure 5 The image shows a periodic line pattern on region A, with a period of 27 nm and an average line width of 13 nm. This demonstrates that the method in this embodiment can prepare a uniform mask layer with large-scale densely packed holes and line patterns.

[0057] S6. Using the PS material mask layer remaining in the above steps as a mask, use CHF3 gas to etch the neutral layer and the silicon in the substrate to transfer the mask layer pattern to the substrate, so as to form a pattern of nanopores and line arrays on the substrate.

[0058] Example 2 Compared with Example 1, the difference is that in step S1, the hydroxyl-terminated PS-r-PMMA solution is replaced with a PS-r-PMMA-r-PGMA solution of the same concentration (solvent is PGMEA), wherein the percentage molar contents of PS component, PMMA component and PGMA component in PS-r-PMMA-r-PGMA are 75%, 24% and 1%, respectively.

[0059] The method in this embodiment has the same effect as in embodiment 1, and it can also prepare uniform large-scale densely packed holes and line patterns.

[0060] Example 3 Compared with Example 1, the difference is that in step S1, the hydroxyl-terminated PS-r-PMMA solution is replaced with a PS-r-PMMA-r-PMPA solution (solvent PGMEA) with a mass percentage of 0.3%, and PMPA (polymethyl methacrylate-β-cinnamyloxyethyl ester) with a percentage molar content of 75%, 22%, and 3% for PS, PMMA, and PMPA components, respectively; at the same time, in step S4, "the film is annealed in vacuum and at 250°C for 30 min" is replaced with "the film is cured and crosslinked in vacuum and under ultraviolet light (wavelength 200-400 nm) for 30 min".

[0061] The method in this embodiment has the same effect as in embodiment 1, and it can also prepare uniform large-scale densely packed holes and line patterns.

[0062] Example 4 Compared with Example 1, the difference is that in step S3, the PS-b-PMMA solution is changed to a same-arm star-shaped block copolymer solution with a mass percentage of 1.5% (PGMEA is the solvent), and the side arms of the same-arm star-shaped block copolymer contain PS-b-PMMA blocks, with the percentage molar contents of PS blocks and PMMA blocks being 65% and 35%, respectively.

[0063] The method in this embodiment has the same effect as in embodiment 1, and it can also prepare uniform large-scale densely packed holes and line patterns.

[0064] Example 5 Compared with Example 1, the difference is that in step S3, the PS-b-PMMA solution is changed to a bottle brush copolymer solution with a mass percentage of 1.5%, the main chain of which is polyacrylate and the side arms contain PS-b-PMMA blocks, with the volume fractions of PS blocks and PMMA blocks being 65% and 35%, respectively.

[0065] The method in this embodiment has the same effect as in embodiment 1, and it can also prepare uniform large-scale densely packed holes and line patterns.

[0066] Example 6 Compared with Example 1, the difference is that in step S4, the thermal annealing method is changed to solvent annealing: the substrate containing the thin film is placed in a transparent quartz box, and tetrahydrofuran vapor is introduced under normal pressure and 30°C. The solvent vapor flow rate is 1 mL / min, and the annealing time is 60 min.

[0067] The method in this embodiment has the same effect as in embodiment 1, and it can also prepare uniform large-scale densely packed holes and line patterns.

[0068] Example 7 Compared with Example 1, the difference is that in step S4, the thermal annealing method is changed to laser annealing, and a carbon dioxide laser is used to anneal the thin film for 20 minutes, in the form of continuous irradiation or pulse mode.

[0069] The method in this embodiment has the same effect as in embodiment 1, and it can also prepare uniform large-scale densely packed holes and line patterns.

[0070] Example 8 Compared with Example 1, the difference lies in step S2, where, based on the exposure process parameters in the electron beam exposure machine of Example 1, a portion of region A (occupying approximately 1 / 4 of the area of ​​region A) undergoes re-exposure. In this re-exposure process, the exposure dose of electron beam exposure (EBL) is 10000mJ. This re-exposed region is designated as C, and its structural schematic diagram is shown below. Figure 6 As shown, the rest is the same. Region A, which has a line pattern, is re-exposed using an electron beam lithography machine. This results in region C being treated with higher intensity light, altering its surface chemical properties. Testing the water contact angles in regions A, B, and C reveals they are 86°, 84°, and 75°, respectively. This indicates that region C in this embodiment changes from strongly hydrophobic to weakly hydrophilic, controlling the copolymer assembly and alignment. The line pattern regions in regions A and C guide the block copolymer to form PMMA phase regions with both layered and columnar phase morphologies, facilitating the subsequent formation of dense lines and close-packed pores, respectively. The cylindrical pattern in region B guides the block copolymer to form PMMA phase regions with columnar phase morphology, enabling the subsequent formation of close-packed pores. Ultimately, different arrangements of line and pore patterns are obtained, and the resulting guide template is shown below. Figure 6 .

[0071] Example 9 Compared to Example 8, the difference lies in step S2, where the "re-exposure treatment" in Example 8 is replaced with "surface treatment of a portion of region A with line patterns using a high-power laser to form region C". In this surface treatment, the laser power is 50W, the time is 10s, and the rest are the same. Testing the water contact angles in regions A, B, and C shows that they are 86°, 84°, and 73°, respectively. Therefore, region C in this example changes from strongly hydrophobic to weakly hydrophilic, controlling the assembly and arrangement direction of the copolymer. The line pattern regions in regions A and C guide the block copolymer to form PMMA phase regions with both layered and columnar phase morphologies, enabling the subsequent formation of dense lines and closely packed pore patterns, respectively. The cylindrical pattern on region B guides the block copolymer to form PMMA phase regions with columnar phase morphology, enabling the subsequent formation of closely packed pore patterns. Finally, lines and pore patterns with different arrangements are obtained, and the obtained guide template is as follows: Figure 6 The method in this embodiment has the same effect as in embodiment 1, and it can also prepare uniform densely packed holes and line patterns of various types.

[0072] As can be seen from Examples 1-9 above, in the method for forming patterns on a substrate according to the present invention, a neutral layer is first prepared on the substrate surface to facilitate the subsequent induction of microphase separation by the block copolymer, resulting in a phase orientation perpendicular to the substrate; then a photoresist layer is formed on it, and the photoresist layer is patterned through a surface treatment process to obtain a guide template or a guide template. The patterning process may result in differences in the surface chemical properties and / or topological structure of different regions of the obtained guide template. A block copolymer film is then covered on the guide template. In the annealing process, the block copolymer in the film undergoes a thermodynamic phase transition. The high sensitivity of the surrounding environment to initial conditions means that the block copolymers in the thin film, based on the differences in surface chemical properties and / or topological structure of different regions on the guiding template, will induce the block copolymers to form phase regions with different morphologies in the regions with different surface chemical properties and / or topological structures during microphase separation. The phase regions with different morphologies are the basis for different patterns. Then, at least one phase region in the phase-separated polymer layer is selectively removed to form patterns such as grooves or holes at the corresponding positions, thereby obtaining a patterned substrate mask layer. Finally, the pattern of the mask layer is transferred to the substrate by etching. In the method of the present invention, the surface properties or topological structures of different regions on the guiding template are different. When guiding the microphase separation of the block copolymer, at least one phase region on the phase-separated polymer layer will have two or more morphologies. Therefore, after etching away at least one phase region, different patterns will be formed in different regions on the mask layer. Thus, the method of the present invention can simultaneously generate at least two large-scale nano-patterns (such as lines and holes) with different functions, uniformity and periodicity in different regions of the substrate in a single process, which greatly simplifies the process flow and the use of different types of materials, and reduces the number of photomasks used and the cost of photolithography / DSA process.

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A method for forming a pattern on a substrate, characterized in that, Includes the following steps: S1. A neutral layer is formed on at least one surface of the substrate; S2. A guide template is formed on the neutral layer, and the guide template is patterned and / or surface treated to form a guide template with a periodic pattern on the neutral layer, wherein the guide template includes at least two regions with different surface properties and / or topological patterns. S3. A block copolymer solution is coated onto the guiding template to form a block copolymer film; the volume fraction of at least one block of the block copolymer in the block copolymer solution is within the range of phase regions capable of forming at least two different morphologies; S4. Anneal the block copolymer film to form a phase-separated polymer layer, the phase-separated polymer layer comprising at least two phase regions formed by the separation of the block copolymer in the block copolymer film; at least one phase region exhibits a periodic arrangement and has at least two different morphologies; S5. Etch at least one phase region of the phase-separated polymer layer and its corresponding neutral layer to obtain a mask layer with at least two different patterns. S6. The pattern of the mask layer is transferred to the substrate by etching.

2. The method for forming a pattern on a substrate as described in claim 1, characterized in that, In step S2, the at least two regions with different surface properties and / or topological patterns include at least two regions with different surface properties, and / or regions with different topological patterns, the different topological patterns including grooves, columns, and holes with different heights and / or shapes.

3. The method for forming a pattern on a substrate as described in claim 1, characterized in that, In step S2, the guide template includes at least one of a bar pattern and a cylindrical pattern; And / or, the guide template includes at least two regions with different surface properties, and the water contact angle between any two regions with different surface properties differs by more than 5°.

4. The method for forming a pattern on a substrate as described in claim 3, characterized in that, In step S2, the guide template includes at least two regions among a first region, a second region, and a third region that have different surface properties and / or topological patterns. The first region includes a periodic bar pattern, the second region includes a periodic cylindrical pattern, and the surface properties of the third region are different from those of the first region and / or the second region.

5. The method for forming a pattern on a substrate as described in claim 1, characterized in that, In step S3, the block copolymer in the block copolymer solution includes at least one of polystyrene-b-polymethyl methacrylate, polystyrene-b-polymethyl acrylate, polystyrene-b-polyisoprene, polystyrene-b-polylactic acid, polystyrene-b-polydimethylsiloxane, polystyrene-b-polytrimethylene carbonate, polystyrene-b-polyvinyl acetate, polystyrene-b-polyvinylpyridine, and polystyrene-b-poly(methyl methacrylate-r-glycidyl methacrylate derivative).

6. The method for forming a pattern on a substrate as described in claim 1, characterized in that, In step S3, when the block copolymer in the block copolymer solution is polystyrene-b-polymethyl methacrylate, the volume fraction of polystyrene blocks in the polystyrene-b-polymethyl methacrylate is 58%-70%, and the volume fraction of polymethyl methacrylate blocks is 30%-42%. And / or, in step S3, the block copolymer in the block copolymer solution includes block copolymers with linear, cyclic, star-shaped or bottle-brush-shaped structures; And / or, in step S3, the mass concentration of the block copolymer solution is 0.5%-3%.

7. The method for forming a pattern on a substrate as described in claim 1, characterized in that, Includes at least one of the following ADs: A. In step S4, the morphology is selected from at least one of layered phase, columnar phase, globular phase and combination thereof; B. In step S4, the annealing process includes at least one of thermal annealing, solvent annealing, laser annealing, and ultraviolet annealing. C. In step S4, the phase region exhibits an orientation structure perpendicular to the substrate; D. In step S4, when at least one phase region exhibits a periodic arrangement, the period of the phase region is L0, and the period of the guiding template in step S2 is L. s The following relationship is satisfied: L s >L0.

8. The method for forming a pattern on a substrate as described in claim 1, characterized in that, In step S1, the neutral layer includes at least one of random copolymers and random copolymers with hydroxyl groups at the ends; And / or, in step S1, the thickness of the neutral layer is 1-20 nm; And / or, in step S2, the guide template includes a photoresist layer, the patterning process includes exposure, development and drying, and the surface treatment includes surface treatment of the photoresist layer using electron beam, ion beam, or extreme ultraviolet light.

9. The method for forming a pattern on a substrate as described in claim 8, characterized in that, The monomer molecules in the random copolymers and the random copolymers with hydroxyl-terminated ends are independently selected from at least one of polystyrene, polymethyl methacrylate, poly(β-cinnamoyl ethyl methacrylate) or polyglycidyl methacrylate.

10. A patterned substrate, characterized in that, It is prepared by the method of forming a pattern on a substrate as described in any one of claims 1-9.

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