Composition for directed self-assembly and patterning method
By using a combination of block copolymer of structural formula (1) and photoacid generator, combined with wet etching technology, the problem of over- or under-etching in the traditional DSA material etching process is solved, achieving efficient patterning and self-assembly, and improving the performance and yield of semiconductor devices.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- RUILI INTEGRATED CIRCUIT CO LTD
- Filing Date
- 2024-11-07
- Publication Date
- 2026-05-08
AI Technical Summary
Traditional block copolymer DSA materials are prone to over-etching or under-etching when etching away monomer polymers, resulting in a high pattern defect rate and affecting the performance and yield of semiconductor devices.
A block copolymer with structural formula (1), a photoacid generator and a solvent are used to generate the block copolymer through aldol condensation reaction, and the photoacid generator is used to acidify it under exposure conditions to form an array structure of the first homopolymer and the second homopolymer. The second homopolymer layer is removed by wet etching to form the target pattern.
It improves the quality of pattern formation and self-assembly efficiency, reduces the pattern defect rate, and enhances the performance and yield of semiconductor devices.
Smart Images
Figure CN121995693A_ABST
Abstract
Description
Technical Field
[0001] This disclosure relates to the semiconductor field, and more particularly to a composition for directional self-assembly and a method for patterning. Background Technology
[0002] Directed self-assembly (DSA) of block copolymers is a technique that uses block copolymers obtained by polymerizing two or more chemically dissimilar monomers. Nanoscale patterns are formed through microphase separation between different blocks, creating pattern transfer templates for the fabrication of related semiconductor devices. Compared to traditional photolithography, DSA using block copolymers eliminates the need for light sources and masks, enabling the generation of large-scale ordered patterns. It offers advantages such as low cost, high resolution, and high throughput. However, traditional DSA materials still have several drawbacks. For example, over-etching or under-etching can easily occur when removing the monomer polymers from the block copolymer, leading to a high pattern defect rate. Therefore, it is necessary to develop novel block copolymer materials to improve pattern formation quality. Summary of the Invention
[0003] According to some embodiments of this disclosure, one aspect of this disclosure provides a composition for directional self-assembly, comprising: a block copolymer having structural formula (1),
[0004]
[0005] R1 to R7 are each independently selected from hydrogen, halogen, saturated or unsaturated C1 to C4 alkyl, C-1 to C-10 fluoroalkyl or (trialkylsilyl) alkenyl groups;
[0006] Photoacid generators and solvents.
[0007] In some embodiments, the block copolymer is composed of a first homopolymer having structural formula (2) and a polymer having structural formula (3).
[0008] The second homopolymer was obtained through reaction.
[0009]
[0010] Among them, R* includes R6 or R7.
[0011] In some embodiments, the step of reacting the first homopolymer and the second homopolymer to obtain the block copolymer includes: dissolving the first homopolymer and the second homopolymer together in a tetrahydrofuran solution and performing an aldol condensation reaction under the action of a catalyst to generate the block copolymer; dissolving the photoacid generator and the block copolymer generated in the reaction in the solvent to obtain the composition.
[0012] In some embodiments, the catalyst is an organic base or an inorganic base.
[0013] In some embodiments, the molar ratio of the first homopolymer to the second homopolymer is in the range of 1:1 to 1:3.
[0014] In some embodiments, the weight-average molecular weight of the first homopolymer ranges from 1000 to 10000 g / mol, and the weight-average molecular weight of the second homopolymer ranges from 3000 to 6000 g / mol.
[0015] In some embodiments, the block copolymer is in the composition at a mass percentage ranging from 5% to 30%, the solvent is in the composition at a mass percentage ranging from 70% to 95%, and the photoacid generator is in the composition at a mass percentage of less than 1%.
[0016] In some embodiments, the solvent comprises esters or ketones.
[0017] According to some embodiments of this disclosure, another aspect of this disclosure also provides a method for directional self-assembly patterning, comprising:
[0018] A substrate is provided; an anti-reflective layer and a neutral layer are formed on the surface of the substrate; a composition layer consisting of the composition is formed on the neutral layer; the composition layer is exposed to cause the composition layer to self-assemble to form an array structure consisting of a first homopolymer layer and a second homopolymer layer; the second homopolymer layer in the array structure is removed to form a target pattern.
[0019] In some embodiments, exposing the composition layer to cause it to self-assemble to form an array structure composed of a first homopolymer layer and a second homopolymer layer, and removing the second homopolymer layer from the array structure to form the target pattern, includes: the exposure light source being ultraviolet light; the photoacid generator in the composition undergoing acid hydrolysis under the irradiation of the ultraviolet light to generate acid, thereby decomposing the block copolymer in the composition into the first homopolymer and the second homopolymer, the decomposed first homopolymer forming the first homopolymer layer, and the decomposed second homopolymer forming the second homopolymer layer; wet etching removing the second homopolymer layer and the wet etching solution to form the target pattern, wherein the etching selectivity ratio of the second homopolymer to the first homopolymer is greater than 95:1.
[0020] According to embodiments of this disclosure, by forming a composition consisting of a block copolymer having the structural formula (1), a photoacid generator, and a solvent, the block copolymer obtained by reacting the first homopolymer and the second homopolymer can achieve high-efficiency decomposition under exposure conditions by the action of the photoacid generator, since the first homopolymer and the second homopolymer are bonded by an acid-crackable acetal.
[0021] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description
[0022] One or more embodiments are illustrated by way of example with corresponding pictures in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Unless otherwise stated, the pictures in the accompanying drawings do not constitute a limitation on scale. In order to more clearly illustrate the technical solutions in the embodiments of this disclosure or the conventional technology, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 This disclosure provides a method for directional self-assembly patterning according to one embodiment.
[0024] Figures 2 to 4 This is a schematic diagram of the structure corresponding to each step of a method for directional self-assembly patterning provided in an embodiment of the present disclosure. Detailed Implementation
[0025] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, those skilled in the art will understand that many technical details have been provided in the embodiments of this disclosure to facilitate a better understanding of the disclosure. However, the technical solutions claimed in this disclosure can be implemented even without these technical details and various variations and modifications based on the following embodiments.
[0026] Guided by Moore's Law, the feature size of components in integrated circuits continues to shrink, and corresponding patterning technologies have also developed and evolved. Extreme ultraviolet (EUVL) patterning, as a next-generation patterning technology, still faces challenges in large-scale semiconductor manufacturing due to its high cost and limited production volume. Directed self-assembly (DSA) of block copolymers is a novel patterning method that has attracted widespread attention from academia and industry due to its high resolution and extremely low cost.
[0027] Directed self-assembly (DSA) of block copolymers is a cutting-edge nanofabrication technology. It utilizes block copolymers, obtained by polymerizing two or more chemically dissimilar monomers, to spontaneously form nanoscale ordered patterns through microphase separation between different blocks under conditions such as thermal annealing. These patterns then serve as templates for pattern conversion in the fabrication of semiconductor devices. Compared to traditional photolithography, DSA eliminates the need for light sources and masks, enabling the generation of large-scale ordered patterns. It offers significant advantages such as low cost, high resolution, and high throughput, thus demonstrating immense potential in the semiconductor industry, particularly in the manufacture of high-density memory and advanced logic chips. However, traditional DSA materials and processes still present some challenges and limitations. Etching to remove the monomer polymers from the block copolymers is a critical step. Over-etching or under-etching can easily occur, leading to a high defect rate and impacting the performance and yield of the final device. Over-etching may reduce the pattern size, affecting structural accuracy and stability; while under-etching may cause connections between patterns, affecting the device's isolation performance.
[0028] Therefore, in order to solve the above problems, this disclosure provides a composition for directional self-assembly.
[0029] According to some embodiments of this disclosure, one aspect of this disclosure provides a composition for directional self-assembly, comprising: a block copolymer having structural formula (1),
[0030]
[0031] R1 to R7 can each be independently selected from hydrogen, halogen, saturated or unsaturated C1 to C4 alkyl, C-1 to C-10 fluoroalkyl or (trialkylsilyl) alkenyl groups; photoacid generators and solvents. The halogen can include, for example, fluorine, chlorine, bromine, and iodine. The saturated or unsaturated C1-C4 alkyl groups include, for example, straight-chain or branched, saturated or unsaturated, substituted or unsubstituted hydrocarbon groups having 1 to 4 carbon atoms (e.g., C1-C4 alkyl, C1-C2 alkyl), for example, having at least 1 carbon atom (i.e., methyl), at least 2 carbon atoms (e.g., ethyl, vinyl), at least 3 carbon atoms (e.g., propyl, isopropyl, propenyl, etc.), at least 4 carbon atoms (butyl, isobutyl, sec-butyl, butane, etc.). The C-1 to C-10 fluoroalkyl groups can be fluorinated alkyl chains containing 1 to 10 carbon atoms. The C-1 fluoroalkyl group is trifluoromethyl (CF3), the C-2 fluoroalkyl group can be pentafluoroethyl (CF3CF2-), and so on, up to the C-10 fluoroalkyl group, which is a fluorinated alkyl chain having ten carbon atoms.
[0032] In some embodiments, the block copolymer is obtained by reacting a first homopolymer having structural formula (2) and a second homopolymer having structural formula (3).
[0033]
[0034] Wherein, R* includes R6 or R7. Exemplarily, the first homopolymer may be a derivative of styrene (PS), and the second homopolymer may be a derivative of polymethyl methacrylate (PMMA), wherein R1 to R7 may each be independently selected from hydrogen, halogen, saturated or unsaturated C1 to C4 alkyl, C-1 to C-10 fluoroalkyl or (trialkylsilyl) alkenyl groups; photoacid generators; and solvents. The halogen can include, for example, fluorine, chlorine, bromine, and iodine. The saturated or unsaturated C1-C4 alkyl groups include, for example, straight-chain or branched, saturated or unsaturated, substituted or unsubstituted hydrocarbon groups having 1 to 4 carbon atoms (e.g., C1-C4 alkyl, C1-C2 alkyl), for example, having at least 1 carbon atom (i.e., methyl), at least 2 carbon atoms (e.g., ethyl, vinyl), at least 3 carbon atoms (e.g., propyl, isopropyl, propenyl, etc.), at least 4 carbon atoms (butyl, isobutyl, sec-butyl, butane, etc.). The C-1 to C-10 fluoroalkyl groups can be fluorinated alkyl chains containing 1 to 10 carbon atoms. The C-1 fluoroalkyl group is trifluoromethyl (CF3), the C-2 fluoroalkyl group can be pentafluoroethyl (CF3CF2-), and so on, up to the C-10 fluoroalkyl group, which is a fluorinated alkyl chain having ten carbon atoms. For example, in a styrene (PS) derivative, R1 can be selected from hydrogen or halogen; R2 can be selected from hydrogen, halogen, saturated or unsaturated C1 to C4 alkyl; R3 can be selected from hydrogen, halogen, saturated or unsaturated C1 to C4 alkyl; R4 can be selected from saturated or unsaturated C1 to C4 alkyl, C-1 to C-10 fluoroalkyl, or (trialkylsilyl)alkenyl groups; and R5 can be selected from hydrogen, halogen, or saturated or unsaturated C1 to C4 alkyl. Alternatively, in a styrene (PS) derivative, R1 can be selected from saturated or unsaturated C1 to C4 alkyl, C-1 to C-10 fluoroalkyl, or (trialkylsilyl)alkenyl groups; R2 can be selected from saturated or unsaturated C1 to C4 alkyl, C-1 to C-10 fluoroalkyl, or (trialkylsilyl)alkenyl groups; and R3 can be selected from hydrogen, halogen, or saturated or unsaturated C1 to C4 alkyl. R4 can be selected from hydrogen, halogen, saturated or unsaturated C1 to C4 alkyl groups, and R5 can be selected from hydrogen, halogen, saturated or unsaturated C1 to C4 alkyl groups, without limitation herein; R* in polymethyl methacrylate (PMMA) derivatives includes R6 or R7, where R6 can be selected from hydrogen, halogen, saturated or unsaturated C1 to C4 alkyl groups, and R7 can be selected from C-1 to C-10 fluoroalkyl groups or (trialkylsilyl)alkenyl groups, or R6 can be selected from C-1 to C-10 fluoroalkyl groups or (trialkylsilyl)alkenyl groups, and R7 can be selected from hydrogen, halogen, saturated or unsaturated C1 to C4 alkyl groups, or both R6 and R7 can be selected from hydrogen, halogen, saturated or unsaturated C1 to C4 alkyl groups, or both R6 and R7 can be selected from C-1 to C-10 fluoroalkyl groups or (trialkylsilyl)alkenyl groups, without limitation herein.
[0035] In some embodiments, the step of reacting a first homopolymer and a second homopolymer to obtain a block copolymer may include:
[0036] A first homopolymer having structural formula (2) and a second homopolymer having structural formula (3) are dissolved together in a tetrahydrofuran solution and subjected to an aldol condensation reaction under the action of a catalyst to generate a block copolymer having structural formula (1). The aldol condensation reaction can be carried out at a temperature range of 25-35°C, and the catalyst can be an organic or inorganic base, such as triethylamine, sodium hydroxide, potassium hydroxide, or potassium tert-butoxide, as shown in reaction formula (1).
[0037]
[0038] A photoacid generator (PAG) and the resulting block copolymer are dissolved in a solvent to obtain a composition for directional self-assembly. In some embodiments, the photoacid generator may include iodonium salts, sulfonium salts, and sulfoxonium salts. These compounds can efficiently generate strong acids, such as trifluoromethanesulfonic acid (CF3SO3H) or non-fluorinated acids (such as HCl or HBr), under irradiation with light of a specific wavelength.
[0039] In some embodiments, the solvent may include esters or ketones, or other nonpolar or weakly polar solvents, aprotic solvents, or halogenated hydrocarbon solvents. For example, ketones may be selected from 2-heptanone, esters may be selected from ethyl acetate, 1,2-propanediol C1-C4 alkyl ether C1-C4 alkyl carboxylic acid esters, C1-C4 alkyl C1-C4 alkyl carboxylic acid esters, and mixtures thereof, nonpolar or weakly polar solvents may be selected from cyclohexane and toluene, polar aprotic solvents may be selected from tetrahydrofuran (THF) and dichloromethane (DCM), and halogenated hydrocarbon solvents may be selected from chloroform and 1,2-dichloroethane. The C1-C4 alkyl group may include methyl (CH3-), ethyl (CH3CH2-), n-propyl (CH3CH2CH2-), and isopropyl (CH3CH(CH3)-), as well as n-butyl (CH3CH2CH2CH2-), sec-butyl (CH3CH2CH(CH3)-), isobutyl (CH3CH(CH3)CH2-), and tert-butyl (C(CH3)3-). The C1-C4 alkyl carboxylic acid ester may include methyl formate, ethyl acetate, and n-propyl propionate. Propanediol (PP) and n-butylbutyrate (N-butylbutyrate), 1,2-propanediol C1-C4 alkyl ethers and C1-C4 alkyl carboxylic esters combine the structural features of 1,2-propanediol ethers and C1-C4 alkyl carboxylic esters. 1,2-Propanediol is an alcohol compound with two hydroxyl groups (-OH), while C1-C4 alkyl ethers refer to ether groups formed by replacing one or two hydroxyl groups of 1,2-propanediol with C1-C4 (i.e., 1 to 4 carbon atoms) alkyl groups (such as methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, or tert-butyl).
[0040] In some embodiments, the block copolymer may comprise 5% to 30% by mass, the solvent may comprise 70% to 95% by mass, and the photoacid generator may comprise less than 1% by mass. The mass percentage of the block copolymer directly affects the kinetics of the self-assembly process and the final structure formed. A block copolymer concentration of 5 wt% to 30 wt% ensures the formation of a stable self-assembled structure and prevents the composition from becoming too viscous, thus affecting coating uniformity and the self-assembly process. A solvent concentration of 70 wt% to 95 wt% helps maintain the fluidity of the solution, facilitating molecular diffusion during coating and self-assembly. A photoacid generator concentration of less than 1 wt% helps avoid over-acidification and improves the stability of the block copolymer.
[0041] In some embodiments, the molar ratio of the first homopolymer to the second homopolymer ranges from 1:1 to 1:3. For example, the molar ratio of the first homopolymer to the second homopolymer can be 1:2, which effectively ensures the surface uniformity of the self-assembled block copolymer and its high adhesion and stability.
[0042] In some embodiments, the weight-average molecular weight (M) of the first homopolymer w The range is 1000-10000 g / mol, and the weight-average molecular weight (M) of the second homopolymer is... w The weight-average molecular weight range is 3000-6000 g / mol. This range ensures that the block copolymer formed by the reaction of the first and second homopolymers has sufficient fluidity to spontaneously self-assemble. The weight-average molecular weight (M...) is... w It can be measured by gel permeation chromatography (GPC), light scattering, and viscometry.
[0043] According to embodiments of this disclosure, by forming a composition consisting of a block copolymer having structural formula (1), a photoacid generator, and a solvent, since the first homopolymer and the second homopolymer are bonded by acid-crackable acetal bonds, the acetal bond is an acid-sensitive chemical bond whose structure includes one oxygen atom connected to two carbon atoms to form a tetrahedral center. Under acidic conditions, the acetal bond is easily broken, leading to a change in molecular structure. Therefore, the block copolymer obtained by reacting the first homopolymer and the second homopolymer can achieve high-efficiency decomposition under exposure conditions through the action of the photoacid generator.
[0044] This embodiment also provides a method for directional self-assembly patterning. The semiconductor structure provided in this disclosure embodiment will be described below with reference to the accompanying drawings. Figure 1 A method for directional self-assembly patterning is provided as an embodiment of this disclosure; Figures 2 to 4 This is a schematic diagram of the structure corresponding to each step of a method for directional self-assembly patterning provided in an embodiment of the present disclosure.
[0045] According to some embodiments of this disclosure, another aspect of this disclosure also provides a method for directional self-assembly patterning, referring to... Figure 1 .
[0046] S100 provides a substrate; exemplaryly, substrate 101 may be a semiconductor material of silicon-on-insulator (SOI), germanium, or diamond, or may be made of materials such as silicon germanium, indium antimonide, lead telluride, indium arsenide, indium phosphide, gallium arsenide, or gallium antimonide. Substrate 101 may also be a doped silicon substrate, for example, substrate 101 may be a silicon substrate doped with an N-type dopant such as phosphorus or arsenic.
[0047] In S200, an anti-reflection layer 102 and a neutral layer 103 are formed on the surface of substrate 101. Exemplarily, the anti-reflection layer 102 can be silicon nitride (SiN) or silicon oxynitride (SiON). Silicon nitride (SiN) is a material with a high refractive index, which can effectively reduce light reflection. It is usually deposited on substrate 101 using processes such as chemical vapor deposition (CVD) or plasma-enhanced chemical vapor deposition (PECVD). The high refractive index and good chemical stability of silicon nitride (SiN) make it an ideal material for anti-reflection layers. Silicon oxynitride (SiON) can be prepared by plasma-enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD) processes.
[0048] The neutral layer 103 serves to provide an interface between the substrate 101 and the composition layer 104 to regulate the interaction between the composition layer 104 and the substrate 101, thereby influencing the directionality and patterning effect of self-assembly. The material of the neutral layer needs to possess chemical stability, meaning it can withstand the heat and chemical treatments during the DSA process without significant chemical changes. Furthermore, its surface energy should be between that of the first and second homopolymers to promote phase separation while avoiding excessively strong interactions with either polymer, which could affect the uniformity and directionality of self-assembly. Additionally, the neutral layer should be compatible with the substrate 101 to ensure good adhesion and stability, preventing peeling or deformation during the DSA process. Exemplarily, the material of the neutral layer may include, but is not limited to, silane coupling agents such as 3-aminopropyltriethoxysilane (APTES) and 3-methacryloyloxypropyltrimethoxysilane (MAPTMS), which can bond to the silicon substrate through chemical bonds while providing appropriate surface energy to guide the self-assembly process. Polymer films: such as polyvinyl alcohol (PVA), polyvinylpyrrolidone (PVP), and polyvinyl butyral (PVB), etc. These polymers have good film-forming properties and chemical stability, and can act as neutral layers to regulate the self-assembly behavior of the first and second homopolymers. Metal oxides: such as silicon dioxide (SiO2), aluminum oxide (Al2O3), titanium oxide (TiO2), etc. These materials have good chemical and thermal stability, and can act as neutral layers to guide the self-assembly process by adjusting surface energy. Self-Assembled Monolayer (SAM): such as a self-assembled monolayer of alkanethiols on a gold surface, which can provide precisely controlled surface energy and guide the self-assembly direction of the block copolymer; the neutral layer 103 may also contain a blend of two or more polymers with different compositions. For example, the blend may contain oligomeric polystyrene and polymethacrylic acid with different molar concentrations. The process for forming the antireflective layer 102 and the neutral layer 103 may include chemical vapor deposition (CVD), physical vapor deposition (PVD), spin coating or atomic layer deposition (ALD), and spin coating.
[0049] S300 forms a composition layer 104 on a neutral layer 103, consisting of a composition for directional self-assembly. Exemplarily, the composition can be spin-coated onto the neutral layer 103 using a spin-coating technique. By rotating the substrate 101 at high speed, the composition is uniformly distributed and rapidly evaporated under centrifugal force, forming a thin and uniform film to form the composition layer 104. The thickness of the composition layer 104 can be set according to process requirements. After spin-coating to form the composition layer 104, baking the composition layer 104 may be included to remove solvents from the composition. The baking temperature range can be 25-60°C, which is relatively low and aims to gently remove solvents while reducing the thermal impact on the block copolymers and photoacid generators in the composition layer.
[0050] S400 exposes the composition layer to cause the composition 104 to self-assemble to form an array structure 105 consisting of a first homopolymer layer 1051 and a second homopolymer layer 1052.
[0051] S500 removes the second homopolymer layer 1052 in the array structure 105 to form the target pattern.
[0052] In some embodiments, the composition layer 104 is exposed to cause the composition layer 104 to self-assemble to form an array structure 105 consisting of a first homopolymer layer 1051 and a second homopolymer layer 1052, and the second homopolymer layer 1052 is removed from the array structure 105 to form a target pattern. The specific steps are as follows.
[0053] The light source for exposing the composition layer 104 can be ultraviolet light (UV). The photoacid generator in the composition is activated under UV irradiation and undergoes an acidolysis reaction to produce a strong acid, thereby decomposing the block copolymer with structural formula (1) in the composition into a first homopolymer with structural formula (2) and a second homopolymer with structural formula (3). The decomposition process is accompanied by self-assembly behavior. The decomposed first homopolymer and second homopolymer rearrange to form a first homopolymer layer 1051 composed of the first homopolymer and a second homopolymer layer 1052 composed of the second homopolymer. The formation of the array structure 105 is based on the interaction force between the first homopolymer and the second homopolymer and their phase separation. Phase separation refers to the process in which a originally uniformly mixed system spontaneously separates into two or more phases due to incompatibility between components or thermodynamic driving forces. The above reaction process is specifically shown in reaction formula (2) and reaction formula (3):
[0054]
[0055] Wet etching removes the second homopolymer layer 1052 and the wet etching solution to form the target pattern. The etching selectivity ratio of the second homopolymer to the first homopolymer is greater than 95:1. For example, the wet etching solution can be methyl ethyl ketone, the wet etching temperature range can be 25-40°C, and the wet etching time range can be 30-60 seconds. Because the wet etching solution exhibits a significant difference in etching selectivity between the first and second homopolymers, the second homopolymer can be completely removed, thereby effectively improving the quality of the target pattern.
[0056] According to embodiments of this disclosure, by forming a composition consisting of a block copolymer having structural formula (1), a photoacid generator, and a solvent, since the first homopolymer and the second homopolymer are bonded by acid-crackable acetal bonds, the photoacid generator undergoes acidolysis under exposure conditions to generate acid, which allows the acetal bonds in the block copolymer having structural formula (1) in the composition to decompose rapidly. Therefore, the composition layer can also self-assemble into an array structure consisting of a first homopolymer layer 1051 and a second homopolymer layer 1052, effectively improving the self-assembly quality and self-assembly efficiency. At the same time, since the wet etching solution has a large difference in etching selectivity for the first homopolymer layer 1051 and the second homopolymer layer 1052, the second homopolymer layer 1052 can be completely etched away, thereby effectively improving the quality of the target pattern.
[0057] In some embodiments, the target pattern can be used to form a device structure in a semiconductor chip, which can be a memory semiconductor chip including a memory device. Exemplarily, the memory device includes a volatile memory device, such as dynamic random access memory (DRAM) or static random access memory (SRAM). The memory semiconductor chip includes semiconductor devices, which include multiple individual devices of various types. These individual devices include various microelectronic devices, such as metal-oxide-semiconductor field-effect transistors (MOSFETs) containing CMOS transistors, system-on-a-scale integrated circuits (LSIs), active devices, or passive devices. In some embodiments, taking DRAM as an example, the memory structure can include peripheral circuitry and a memory region. The peripheral circuitry region includes transistors, passive devices, or active devices, wherein the transistors include doped source / drain regions and gate structures.
[0058] Those skilled in the art will understand that the above embodiments are specific examples of implementing this disclosure, and in practical applications, various changes in form and detail may be made without departing from the spirit and scope of the embodiments of this disclosure. Any person skilled in the art can make various modifications and alterations without departing from the spirit and scope of the embodiments of this disclosure; therefore, the scope of protection of the embodiments of this disclosure should be determined by the scope defined in the claims.
Claims
1. A composition for directional self-assembly, comprising: Block copolymers having structural formula (1), R1 to R7 are each independently selected from hydrogen, halogen, saturated or unsaturated C1 to C4 alkyl, C-1 to C-10 fluoroalkyl or (trialkylsilyl) alkenyl groups; Photoacid generators and solvents.
2. The composition according to claim 1, characterized in that, The block copolymer is obtained by reacting a first homopolymer having structural formula (2) and a second homopolymer having structural formula (3). Among them, R* includes R6 or R7.
3. The composition according to claim 2, characterized in that, The step of reacting the first homopolymer and the second homopolymer to obtain the block copolymer includes: The first homopolymer and the second homopolymer were dissolved together in a tetrahydrofuran solution and subjected to an aldol condensation reaction under the action of a catalyst to generate the block copolymer. The photoacid generator and the block copolymer generated by the reaction are dissolved in the solvent to obtain the composition.
4. The composition according to claim 3, characterized in that, The catalyst is an organic base or an inorganic base.
5. The composition according to claim 2, characterized in that, The molar ratio of the first homopolymer to the second homopolymer is in the range of 1:1 to 1:
3.
6. The composition according to claim 2, characterized in that, The weight-average molecular weight of the first homopolymer ranges from 1000 to 10000 g / mol, and the weight-average molecular weight of the second homopolymer ranges from 3000 to 6000 g / mol.
7. The composition according to claim 2, characterized in that, The block copolymer comprises 5% to 30% by mass in the composition, the solvent comprises 70% to 95% by mass in the composition, and the photoacid generator comprises less than 1% by mass in the composition.
8. The composition according to claim 1, characterized in that, The solvent includes esters or ketones.
9. A method for directional self-assembly patterning, characterized in that, include: Provide substrate; An anti-reflective layer and a neutral layer are formed on the surface of the substrate; A composition layer comprising the composition of any one of claims 1-8 is formed on the neutral layer; The composition layer is exposed to cause it to self-assemble, thereby forming an array structure consisting of the first homopolymer layer and the second homopolymer layer. The second homopolymer layer in the array structure is removed to form the target pattern.
10. The method according to claim 9, characterized in that, Exposure of the composition layer to cause self-assembly of the composition layer to form an array structure composed of a first homopolymer layer and a second homopolymer layer, and removal of the second homopolymer layer from the array structure to form the target pattern, includes: The exposure light source is ultraviolet light. Under the irradiation of the ultraviolet light, the photoacid generator in the composition undergoes acid hydrolysis to produce acid, thereby decomposing the block copolymer in the composition into the first homopolymer and the second homopolymer. The decomposed first homopolymer constitutes the first homopolymer layer, and the decomposed second homopolymer constitutes the second homopolymer layer. Wet etching removes the second homopolymer layer and the wet etching solution to form the target pattern, wherein the etching selectivity ratio of the second homopolymer to the first homopolymer is greater than 95:1.