Polymer brush and lithography patterning method using the polymer brush.

Abstract

The present invention provides a polymer brush that mediates interfacial interactions between photoresist and inorganic substrates. [Solution] Polymer brushes are provided that include a plurality of repeating units, some of which have one or more grafting groups and some of which have one or more interfacial modifier groups. The grafting groups are selected based on the properties of the inorganic substrate, and the interfacial modifier groups are selected based on the properties of the photoresist that interact with the grafting groups. A lithographic patterning process and an electronic device including at least one integrated circuit formed by the lithographic patterning process are also provided. The process includes providing an inorganic substrate, depositing the disclosed polymer brush on the inorganic substrate, depositing a photoresist on the polymer brush, masking the photoresist with a photomask having a pattern, and irradiating the masked photoresist with energy to form an etch mask. The inorganic substrate is then etched. [Selected figure] Figure 2

Description

Technical Field

[0001] The present disclosure relates to a lithography material for extreme ultraviolet (EUV) lithography, and more particularly to a polymer brush that mediates the interfacial interaction between a photoresist and an inorganic substrate.

Background Art

[0002] Extreme ultraviolet (EUV) lithography is a lithography technique used in semiconductor manufacturing that utilizes extreme ultraviolet light to transfer a pattern from a photomask to a resist. The pattern is then transferred from the resist to a hard mask via etching, and from the hard mask to a semiconductor material via further etching. EUV light has a wavelength of approximately 124 - 10 nm, which is close to the X-ray region. The short wavelength provided by EUV light enables high-resolution patterning in semiconductor manufacturing.

[0003] Photolithography is a technique commonly used in semiconductor manufacturing to etch an integrated circuit pattern onto a semiconductor wafer. Photolithographic patterning involves coating a substrate material with a photosensitive resist material, referred to herein as a photoresist. The photoresist is selectively masked by a photomask designed with the pattern to be etched onto the semiconductor. It is irradiated with an energy source such as electromagnetic radiation or an electron beam. The unmasked portions of the photoresist are exposed to the energy source. When the photoresist is exposed to the energy source, a chemical reaction occurs, making the selected portions of the photoresist soluble in a developer solution and thus removable during the development step of the lithography process. Removing the soluble portions during the development step creates the patterned photoresist. The patterned photoresist is also referred to as an "etch mask". This pattern is then transferred from the etch mask to the semiconductor or other substrate material during a subsequent etching step. In these steps, the portions of the substrate not covered by the etch mask are etched.

[0004] The location of the soluble portion of the photoresist depends on the selection of the photoresist material and the developer. The developer is a solvent that immerses the photoresist after exposure to the energy source. Immersion in the developer enables removal of the soluble portion of the photoresist. Rinsing with a solvent after development can assist in the removal. The photoresist can be classified into either a positive resist or a negative resist. When a positive resist undergoes negative development, the portion of the photoresist that was not exposed to the energy source (i.e., the masked portion) is soluble in the developer. However, when a positive resist undergoes positive development, the portion that was exposed to the energy source (i.e., the unmasked portion) is soluble in the developer.

[0005] By convention, the electromagnetic radiation emitted by the energy source used in the photolithography process had wavelengths in the range of 436 nm (blue light), 365 nm (near ultraviolet (UV)), or 248 - 193 nm (deep UV). The feature size of the pattern to be imprinted on the semiconductor depends to some extent on the wavelength of the radiation used. That is, the minimum imprintable feature is limited by the shortest wavelength provided by the energy source. As technology advances to require smaller devices containing a greater number of integrated circuits, shorter wavelengths are more desirable. Therefore, various types of next-generation lithography technologies that can provide these shorter wavelengths are being explored and developed. SUMMARY OF THE INVENTION PROBLEMS TO BE SOLVED BY THE INVENTION

[0006] One type of next-generation lithography is a photolithography technique called extreme ultraviolet (EUV) lithography. EUV lithography utilizes light in the 124 - 10 nm (EUV) region. For high-resolution patterning in semiconductor manufacturing, EUV with a wavelength of approximately 13.5 - 10 nm generated by a laser-driven tin (Sn) plasma source is often used. This high-resolution patterning is generally performed using a positive resist that undergoes positive development, but positive resists and negative development can be used as well. However, while EUV lithography enables the fabrication of smaller semiconductor chips, there are issues associated with its use.

[0007] One of these issues occurs during the adhesion of the photoresist to the underlying substrate material, or substrate (e.g., inorganic hard mask (HM), metal, semiconductor material, etc.). For example, when using small-sized patterns, the capillary force may become larger than the adhesion interaction between the photoresist and the substrate. If the photoresist does not adhere properly to the substrate, pattern collapse may occur. In addition, if residues from the photoresist remain after development and rinsing, the pattern may be disrupted. Therefore, techniques for achieving stable adhesion and residue-free conditions between the photoresist and the underlying substrate without requiring additional costly or time-consuming processing steps, or both, are of interest.

Means for Solving the Problems

[0008] Various embodiments of the present invention are directed to a polymer brush having a plurality of repeating units, where a portion of the plurality of repeating units includes one or more grafting groups and one or more interface adjustment groups, and optionally one or more CrackableIt has a group (cleavable group). The graft group is selected based on the identity of the inorganic substrate, such as an inorganic hard mask, to which the group is to be bonded. Examples of the graft group can include alkynes, primary hydroxyls, secondary hydroxyls, acrylic acids, epoxies, alkenes, phosphonic acids, propargyls, phosphonate esters, amines, carboxylic acids, and alkoxysilanes. Examples of the inorganic hard mask material can include silicon, titanium nitride, titanium oxides, titanium oxynitrides, tantalum nitride, hafnium oxides, niobium nitride, lanthanum oxide, silicon oxides, silicon oxynitrides, zirconium oxides, and tin oxides. The interface adjustment group is selected based on the properties of the photoresist that interacts with the group. Examples of the adjustment group can include acidic groups, phenyl groups, methoxy groups, ethylene groups, hydrogen atoms, methyl groups, and trifluoromethyl groups.

[0009] Further embodiments are directed to the process of lithographic patterning. The process includes providing an inorganic substrate such as an ultrathin inorganic hard mask, depositing a polymer brush on the inorganic substrate, and depositing a photoresist on the polymer brush. The polymer brush can comprise a plurality of repeating units, and a portion of the plurality of repeating units has one or more graft groups, one or more interface adjustment groups, and optionally one or more Crackable groups. Examples of the photoresist can include acrylic photoresists, phenolic photoresists, and hybrid photoresists. The process further includes masking the photoresist using a photomask having a pattern. Energy such as extreme ultraviolet light is applied to the masked photoresist. This energy may be derived from a laser-driven tin (Sn) plasma. An etch mask is then formed by developing the photoresist. The pattern is then transferred to the inorganic substrate by etching the portion of the inorganic substrate exposed by the etch mask.

[0010] Further embodiments are directed to an electronic device comprising at least one integrated circuit chip prepared by an extreme ultraviolet lithography patterning process. The electronic device can further comprise at least one additional integrated circuit chip. The extreme ultraviolet lithography patterning process includes providing an inorganic substrate, depositing a polymer brush on the inorganic substrate, and depositing a photoresist on the polymer brush. The polymer brush can comprise a plurality of repeating units, and a portion of the plurality of repeating units can have one or more grafting groups, one or more interface modulating groups, and optionally one or more Crackable groups. The process further includes masking the photoresist using a photomask having a pattern. The masked photoresist is irradiated with extreme ultraviolet light. An etch mask is then formed by developing the photoresist. The pattern is then transferred to the inorganic substrate by etching the portion of the inorganic substrate exposed by the etch mask.

[0011] Embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings.

Brief Description of the Drawings

[0012]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

DETAILED DESCRIPTION OF THE INVENTION

[0013] Disclosed herein is a polymer brush designed to mediate the interfacial interaction between a photoresist and an inorganic substrate. This mediation results in improved adhesion in some embodiments. A polymer brush is a polymeric molecule having repeating units with at least one functional group capable of grafting (i.e., covalently bonding) to a substrate. The polymer brushes disclosed herein are grafted onto the surface of an inorganic substrate and mediate the interaction with the photoresist. The polymer brushes can be synthesized by the polymerization of various monomers. The properties of the monomers determine the properties and reactivity of the polymer brushes. The monomers can have functional groups for grafting to various inorganic materials, functional groups that enable the polymer to Crack do so, functional groups that interact with the photoresist, functional groups that interact with solvents and developers, functional groups that collect photons, etc. Further, the polymer brushes disclosed herein can be formulated in a solvent that can be spin-cast, and thus do not require significant processing complexity or cost. The photoresist 108 adheres to the polymer brush 104 grafted to the inorganic hard mask 112. The polymer brush has repeating units determined by the properties of the polymerized monomers. The repeating units include grafting, interfacial interaction with the photoresist, and Crack characteristicsIt has functional groups based on groups that affect the properties and interactions of the polymer brush 104 such as sex. Examples of polymer brushes can include vinyl polymers, epoxy polymers, polyester polymers, polyurethane polymers, polyamide polymers, polycarbonate polymers, polyurea polymers, polyether polymers, polyimide polymers, and the like. In some embodiments, the average molecular weight of the polymer brush is in the range of 2,000 to 10,000 Da (g / mol). However, in some embodiments, the average molecular weight of the polymer brush may also be in the range of 400 to 10,000,000 Da.

[0014] Figure 1 is a schematic diagram 100 showing a stack of layers 104, 108, 112, and 116 for EUV lithography patterning according to some embodiments of the present disclosure. The stack includes a polymer brush 104 between a photoresist 108 and an inorganic hard mask 112 on a semiconductor wafer 116. Although the polymer brush 104 is shown as being bonded to the inorganic hard mask 112 covering the semiconductor wafer 116, in some embodiments, additional layers may be present. For example, it can include an organic underlayer (e.g., carbon or polymer) or a dielectric layer (e.g., silicon dioxide or silicon oxynitride) or both. The process of forming the layers 104, 108, 112, and 116 will be discussed in detail with respect to Figure 2.

[0015] Examples of the photoresist layer 108 can include phenolic, acrylic, or hybrid (phenolic-acrylic) chemically amplified photoresists. Examples of phenolic photoresists can include polyoxybenzylmethylene glycol anhydride (Bakelite), cresol-formaldehyde novolak resins, copolymers of polyhydroxystyrene modified with ketal-based protecting groups or tert-butyloxycarbonyl protecting groups, etc. Examples of acrylic photoresists can include poly(methyl methacrylate) (PMMA), polyacrylate, norbornane lactone methacrylate (NLM) / methyl adamantane methacrylate (MAdMA) copolymer, etc. Hybrid photoresists are polymers such as a combination of a phenolic monomer and an acrylic monomer, a polyhydroxystyrene / MAdMA copolymer. In some embodiments, the photoresist 108 is prepared by dissolving a phenolic, acrylic, or hybrid monomer in an organic solvent (e.g., propylene glycol monomethyl ether acetate or cyclohexanone) and adding a suitable photoacid generator (e.g., triphenylsulfonium perfluorobutanesulfonate) and an alkaline quencher (e.g., tetrabutylammonium lactate). However, commercially available or pre-formulated photoresists can also be used. In some embodiments, the thickness of the photoresist ranges from approximately 30 nm to 50 nm, but can range from approximately 1 nm to 500 μm.

[0016] The photoresist 108 adheres to the polymer brush 104 grafted to the inorganic hard mask 112. The polymer brush has repeating units determined by the properties of the polymerized monomers. The repeating units have functional groups by groups that affect the properties and interactions of the polymer brush 104, such as grafting, interfacial interaction with the photoresist, and cleavage properties. Examples of polymer brushes can include vinyl polymers, epoxy polymers, polyester polymers, polyurethane polymers, polyamide polymers, polycarbonate polymers, polyurea polymers, polyether polymers, polyimide polymers, etc. In some embodiments, the average molecular weight of the polymer brush is in the range of 2,000 to 10,000 Da (g / mol). However, the average molecular weight of the polymer brush may be in the range of 400 to 10,000,000 Da in some embodiments.

[0017] The polymer brush 104 includes repeating units having at least one functional group capable of grafting to the inorganic hard mask 112 at one or more locations. The functional group that binds to the inorganic hard mask 112 is referred to herein as a "graft group". Examples of graft groups can include alkynes, primary hydroxyls, secondary hydroxyls, acrylic acids, epoxies, alkenes, phosphonic acids, propargyls, phosphonate esters, amines, carboxylic acids, alkoxysilanes, etc. The selection of the graft group is based, at least to some extent, on the reactivity between the graft group and the underlying substrate. This will be discussed in detail in connection with Figure 2.

[0018] The polymer brush 104 also includes repeating units having at least one adjustable functional group that interacts with the photoresist 108. This functional group is referred to herein as an "interface adjustment group". Adjusting the functional group refers to selecting the functional group based on its properties (e.g., charge, acidity, size, polarity, etc.). Examples of such interactions can include promoting photoresist adhesion, increasing photon uptake, improving photoresist performance, etc. The interface adjustment group may also affect the surface energy or contact angle of the polymer brush 104 with water. Examples of the interface adjustment group can include acidic groups (e.g., phenol, sulfonic acid, fluorosulfonic acid, carboxylic acid, acrylic acid, etc.), phenyl groups, methoxy groups, ethylene groups, hydrogen atoms, methyl groups, trifluoromethyl groups, etc.

[0019] In addition, the polymer brush 104 may optionally include repeating units having functional groups that can be used in subsequent reactions. Crackable This functional group is referred to herein as a " Crackable group". In some embodiments, Crackable the group is a tertiary ester. Crackable Further examples of the group can include primary and secondary esters, sulfate esters, phosphate esters, etc. The method for Cause to crack the polymer brush 104 can include applying heat, acid, photons, etc. For example, exposure to 172 nm light and a developer solution can Crackable the methyl ester Crack groups. In addition, Crack performing can be achieved by a combination of two or more Crack methods. The Crack of the polymer brush 104 from the surface of the inorganic hard mask 112 enables reprocessing or wet etching of the hard mask 112. In addition, Crack it reduces the amount of residue left behind by the photoresist 108, thereby preventing pattern breaks or scumming caused by the residue.

[0020] The inorganic hard mask (HM) 112 onto which the polymer brush 104 is grafted can be made from various materials. In some embodiments, the inorganic HM 112 is a transition metal oxide or a lanthanide oxide. The inorganic HM 112 can also be a transition metal nitride or a lanthanide nitride. Further, the inorganic HM 112 can be a transition metal oxynitride or a lanthanide oxynitride. Examples of these inorganic HM 112 materials include silicon, titanium nitride (TiN), titanium oxide (TiO x ), titanium oxynitride (TiO x N y ), tantalum nitride (TaN), hafnium oxide (HfO x ), niobium nitride (NbN), lanthanum oxide (La2O3), low temperature oxide (LTO), silicon oxide (SiO x ), silicon oxynitride (SiO x N y ), zirconium oxide (ZrO x ), tin oxide (SnO x ), etc. In these chemical formulas, "x" and "y" represent the number of oxygen or nitrogen atoms, respectively (e.g., 1, 2, or 3 atoms). In some embodiments, the inorganic HM 112 is an ultrathin hard mask (i.e., an inorganic hard mask having a thickness of approximately 5 nm or less).

[0021] The pattern created in the photoresist is transferred onto the inorganic hard mask 112 and then onto the semiconductor wafer 116. This transfer includes etching the portion of the substrate where the photoresist was removed during development. The transfer can optionally include a step in which the pattern is first transferred to a layer between the inorganic HM 112 and the semiconductor wafer 116. This is discussed in detail above. Examples of semiconductor wafer 116 materials can include silicon (Si), germanium (Ge), silicon-germanium (Si-Ge), graphene, organic semiconductors, silicon carbide (SiC), gallium arsenide (GaAs), gallium nitride (GaN), indium gallium arsenide (InGaAs), etc. Silicon can be amorphous silicon (aSi), crystalline silicon (cSi), or polycrystalline silicon (poly-Si).

[0022] Figure 2 is a flow diagram illustrating a process 200 for forming a polymer brush 104 that mediates the adhesion of a photoresist 108 to an inorganic hard mask 112, according to some embodiments of the present disclosure. The polymer brush 104 is formed by the polymerization of one or more types of monomers. This is shown in step 204. Examples of monomers that can be polymerized in the synthesis of the polymer brush 104 can include acrylic esters, acrylamides, methacrylic esters, methacrylamides, vinyl esters, vinyl ethers, olefins, etc. The monomers can be of the substituted type, unsubstituted type, or both. In some embodiments, the polymer brush 104 is formed by the polymerization of a diol compound and a diisocyanate, the condensation polymerization of a diol compound or a diamine compound and a dicarboxylic acid, the ring-opening polymerization of a lactone or a lactam, the condensation polymerization of an aminocarboxylic acid, etc.

[0023] The monomers forming the polymer brush 104 are selected based on the desired properties of the resulting polymer brush 104. At least one graft group, at least one interfacial adjustment group, and optionally at least one CrackableThe monomers containing the groups are polymerized to form the polymer brush. In some embodiments, each of these functional groups is on a different type of monomer. However, monomers containing two or more of the functional groups can also be used. For example, one type of monomer may contain two graft groups or one graft group and one surface conditioning group. Additionally, rather than being initially bonded to the monomer, the functional groups can also be formed during the polymerization process or in subsequent reactions.

[0024] The polymer brush 104 can be formed from the polymerization of one type of monomer or from the polymerization of two or more types of monomers. For example, the polymer brush 104 can be made from a certain type of monomer having both a graft group and a surface conditioning group. The polymer brush 104 can also be made from one type of monomer having only a graft group and one type of monomer having only a surface conditioning group. Polymerizing one type of monomer results in a homopolymer (i.e., a polymer having one type of repeating unit), while polymerizing two or more types of monomers results in a copolymer (i.e., a polymer having two or more types of repeating units). Examples of the structure and synthesis of the polymer brush are discussed in detail with respect to FIGS. 3, 4, and 5.

[0025] In some embodiments, the graft group is selected based on an inorganic hard mask (HM) 112 that forms a stable bond. For example, a phosphonic acid graft group binds to metal oxides (e.g., TiO x , La2O3, HfO x , ZrO x , SnO x , etc.), and a terminal alkyne or alkene graft group binds to a silicon surface (e.g., aSi, cSi, poly-Si, silicon hydride, etc.). Further examples of graft groups that bind to metal oxides can include phosphonic acid esters, hydroxyls, alkoxysilanes, etc. When the inorganic HM112 material is silicon oxide (SiO x ) or silicon oxynitride (SiO x Ny ) When this is the case, hydroxyl graft groups are often used. Further, acidic graft groups (e.g., phosphonic acid, carboxylic acid, acrylic acid, etc.) bind to the SiN surface, and alkene graft groups bind to metal oxides such as TiO2, ZnO, ZrO2, SnO2, etc.

[0026] The polymer brush 104 is deposited on the inorganic HM112 substrate. This is shown in step 208. A mixture containing the polymer brush 104 in an organic solvent is prepared. In some embodiments, the polymer brush 104 is formulated in this organic solvent. Examples of organic solvents that can be used can include propylene glycol monomethyl ether acetate (PGMEA), propylene glycol methyl ether (PGME), 4-methyl-2-pentanol (4M2P), cyclohexanone (CHX), ethyl 3-epoxypropionate (EEP), n-butyl acetate (nBA), etc. The layer of the solvent / polymer mixture is deposited on the substrate by spin casting or spin coating. The coated substrate is then baked at a temperature ranging from approximately 18 °C to 350 °C to remove the solvent and to promote the binding of the graft groups to the substrate surface. All ungrafted portions of the polymer brush can be removed by rinsing with an organic solvent (e.g., PGMEA, PGME, 4M2P, CHX, EEP, nBA, etc.).

[0027] The photoresist 108 is then deposited on the grafted polymer brush 104. This is shown in step 212. Various coating processes can be used to apply the photoresist 108. Examples of these coating processes can include spin coating, spray coating, dip coating, knife edge coating, printing techniques (e.g., ink jet or screen printing), spin casting, etc. The coating can be performed in a single coating step or multiple coating steps. Using multiple coating steps can provide better control over the entire coating process. For example, a series of spin coatings can be used to form a desired thickness in the range from a few nanometers to a few microns. In some embodiments, after coating the photoresist on the polymer brush 104 and the substrate 112, additional heating steps or solvent evaporation steps or both can be performed to cure the photoresist layer.

[0028] Following the formation of the photoresist layer 108, lithographic patterning using extreme ultraviolet (EUV) light is performed. This is illustrated in step 216. Various EUV light sources can be used. EUV light sources for lithography generally have a high average output (e.g., 100 W or more) with a 2% bandwidth having a central wavelength of 13.5 nm. For example, a laser-driven tin (Sn) plasma using a high-power drive laser having a wavelength shorter than approximately 1 μm can be utilized. In some embodiments, the drive laser is a pulsed laser. However, the drive laser can also be a solid-state laser, a gas-discharge laser, or an excimer laser. Examples of drive laser sources can include neodymium-doped yttrium aluminum garnet (Nd:YAG), erbium-doped yttrium aluminum garnet (Er:YAG), ytterbium-doped yttrium aluminum garnet (Yb:YAG), titanium sapphire (Ti:Sapphire), neodymium vanadate (Nd:Vanadate), and the like. It should also be noted that in some embodiments, patterning can also be performed using electron beam (e-beam) lithography or immersion photolithography rather than EUV lithography.

[0029] A photomask having the desired pattern is used to partially mask the photoresist prior to exposure to the energy source. Exposure of the photoresist to EUV light causes a chemical reaction in the unmasked portions of the photoresist. Using a positive resist for negative development, the chemical reaction changes the unmasked portions from soluble to insoluble in the developer. However, using a positive photoresist for positive development, the chemical reaction changes the unmasked portions from insoluble to soluble in the developer.

[0030] To promote the desired solubility switch, the process optionally may subsequently perform a hard bake (i.e., post-exposure bake (PEB)). In some embodiments, the coating material is heated at a temperature in the range from about 45°C to 150°C. However, the coating material can also be heated at a temperature in the range from about 50°C to 130°C, or from about 60°C to 110°C. In some embodiments, the PEB is performed for at least about 0.1 minute. However, the PEB can also be performed from about 0.5 minute to about 30 minutes or from about 0.75 minute to about 10 minutes.

[0031] The soluble portion of the photoresist is removed by exposing it to a developer solution and then subsequently rinsed. In some embodiments, the developer solution is an aqueous solution of n-butyl acetate or tetramethylammonium hydroxide (TMAH). A diluted aqueous solution of sodium carbonate (Na2CO3) or potassium carbonate (K2CO3) can likewise be used as the developer solution. Additionally, aqueous-based developer solutions such as buffered sodium hydroxide (NaOH), buffered potassium hydroxide (KOH), a TMAH aqueous solution with a surfactant added, a mixture of NaOH and KOH, etc. can be used. Examples of solutions or solvents for rinsing away the soluble photoresist material after treatment with the developer solution can include deionized water, water with a surfactant added, a mixture of water with a hydrous alcohol, etc.

[0032] The polymer brush 104 can be left on the inorganic hard mask (HM) 112. However, if the polymer brush 104 has Crackable groups, the polymer brush 104 can be partially or completely removed from the substrate during or after patterning. The removal of the polymer brush 104 is Crackable achieved by applying reaction conditions that cleave the bond at the group. Examples of these reaction conditions can include an acid, heat, photon irradiation, etc. Combinations of two or more of these conditions can also be used. Crackable The polymer that has been Crack formed can then be rinsed away using an organic solvent.

[0033] Following the development of the photoresist 108, a pattern (i.e., the portion of the photoresist that was removed during the development of the photoresist 108) is etched onto the inorganic HM112. However, it should be noted that the methods described herein can also be applied to etching onto a silicon wafer or other substrate layer. Further, other examples of etching processes that can be used can include ion beam etching, plasma etching, laser ablation, etc., but in some embodiments, the inorganic HM112 or other substrate is etched by reactive ion etching (RIE).

[0034] FIG. 3 is a conceptual diagram 300 of block structures 302, 306, and 310 of three examples of a general polymer brush according to some embodiments of the present disclosure. The general polymer brushes represented by the block structures 302, 306, and 310 each have some combinations of repeating units with graft groups 314, Crackable groups 318, and interfacial adjustment groups 322. The functional groups 314, 318, and 322 are represented by squares, triangles, and circles, respectively. However, these shapes are for illustrative purposes only and do not represent the actual shapes of the functional groups or monomers in the polymer brush. The molecular structures of examples of polymers having the attached functional groups 314, 318, and 322 are discussed in detail with respect to FIG. 4.

[0035] The x, y, and z portions of the polymer chains in the polymer brush block structures 302, 306, and 310 represent portions of polymer chains having different types of repeating units (i.e., repeating units given by different monomers or having different functional groups or both). The x portion of the first block structure 302 is a portion of a chain having repeating units with graft groups 314, and the y portion of the first block structure 302 is CrackableIt is a portion of a chain having a repeating unit with a base 318, and the z portion of the first block structure 302 is a portion of a chain having a repeating unit with an interface adjustment base 322.

[0036] The x portion of the second block structure 306 is a portion of a chain having a repeating unit with both a grafting base 314 and Crackable the base 318, and the y portion of the second block structure 306 is a portion of a chain having a repeating unit with an interface adjustment base 322. The third block structure 310 represents a certain alternative copolymer having a repeating unit with a grafting base 314, Crackable the base 318, and an interface adjustment base 322. In some embodiments, the polymer brush disclosed herein has more than one type of each functional group 314 or 318 or 322 or combinations thereof in one repeating unit. For example, the polymer brush 104 may have both a phenol and a methoxy interface adjustment base 322 in one repeating unit.

[0037] It should also be noted that other combinations of monomers and functional groups are possible. For example, the polymer brush 104 may have one repeating unit with both a grafting base 314 and an interface adjustment base 322. In addition, in some embodiments, the polymer brush 104 Crackable does not have the base 318. Further, the polymer brush 104 can have more than one of each chain portion. For example, the polymer brush represented by the block structure 302 may have other portions containing a repeating unit with a grafting base 314 in addition to its x portion. The polymer brush 104 can also include portions having a repeating unit with a functional group other than the grafting base 314, Crackable the base 318, or the interface adjustment base 322.

[0038] The relative lengths of the chain portions of the polymer brush 104 (i.e., the number of repeating units within the chain portion) may vary relative to each other. When the partial length changes, the properties of the polymer brush 104 are affected. For example, increasing the number of grafting groups 314 by making the x portion longer relative to the y and z portions of the first block structure 302 can increase the density of bonding sites for grafting the polymer brush 104 to the inorganic HM112. In addition, increasing or decreasing the number of interfacial adjustment groups 322 by making the z portion longer relative to the x and y portions of the polymer brush represented by the first block structure 302 can change the nature of the interaction between the polymer brush 104 and the photoresist 108.

[0039] Furthermore, the number of portions of a particular repeating unit can be increased or decreased. For example, rather than increasing the length of the x portion of the polymer brush represented by the first block structure 302, additional chain portions having repeating units with grafting groups 314 may be included to increase the density of bonding sites. These chain portions may be the x portion, or these chain portions may be part of another repeating unit having the same or different grafting groups 314. The length and frequency of the chain portions can be controlled using monomer selection and polymerization conditions.

[0040] FIG. 4 is a schematic representation 400 of the molecular structures of four example polymer brushes 404, 408, 412, and 416 according to some embodiments of the present disclosure. The x, y, and z portions of the polymer brushes 404 and 408 correspond to the x, y, and z portions of the first polymer brush - block structure 302 illustrated in FIG. 3. The R1 groups within the x portions of the polymer brushes 404 and 408 are substituents having at least one grafting group 314. The methyl - ester groups within the y portions of the polymer brushes 404 and 408 are CrackableIt is the group 318. The R2 groups within the z portions of the polymer brushes 404 and 408 are acidic interface - adjusting groups 322, and the R3 group may be a hydrogen atom, a methyl group, or a trifluoromethyl group.

[0041] The x and y portions of the polymer brush 412 correspond to the x and y portions of the second polymer - brush block structure 306 illustrated in FIG. 3. However, different from the x portion of the second block structure 306, the x portion of the polymer brush 412 Crackable does not contain the group 318. The x portion of the polymer brush 412 has repeating units with R1 graft groups 314, and the y portion of the polymer brush 412 has repeating units with phenolic interface - adjusting groups 322. The polymer brush 416 is an alternative copolymer corresponding to the third polymer - brush block structure 310 illustrated in FIG. 3. The carboxylic acid groups and R3 groups on the polymer brush 416 act as interface - adjusting groups 322. Further, the R1 group is a substituent of at least one graft group 314, and the ester moiety Crackable is the group 318.

[0042] FIG. 5 is a diagram 500 showing processes 500 - 1 and 500 - 2 for forming two example polymer brushes 508 and 516 according to some embodiments of the present disclosure. In these reactions, the polymer brushes 508 and 516 are formed by bonding to a polymer pre - selected with alkyne - graft groups 314. In the first of the two reactions, 500 - 1, the poly(maleic anhydride) polymer 504 is the starting material for the polymer brush 508. This poly(maleic anhydride) polymer 504 has an R 4 group that acts as an interface - adjusting group on the resulting polymer brush. R 4Examples of the base can include a phenyl group, a methoxy group, an ethylene group, etc. In process 500-1, poly(maleic anhydride) polymer 504 is combined with 4-pentin-1-ol, which is an alcohol with a terminal alkyne moiety. The mixture is reacted at approximately 120 °C for approximately 2 hours. This anhydride ring-opening reaction forms a polymer brush 508 having an alkyne-graft group bonded to the ester moiety.

[0043] In the second reaction 500-2, polyhydroxystyrene (PHOST) 512 is combined with 6-iodo-1-hexyne and potassium carbonate (K2CO3) in an acetone solution. The solution is heated to form a polymer brush 516 derived from PHOST having a phenol surface conditioning group 322 on the repeating unit of the x portion and an alkyne-graft group 314 on the repeating unit of the y portion. The x and y portions of the PHOST-derived polymer brush 516 can be of any length and can be partially changed to the same length or different lengths. By adjusting the stoichiometric amount of this reaction, the number of alkyne-graft groups can be varied.

[0044] Figure 6 is a diagram showing process 500-3 for grafting polymer brush 508 onto an inorganic hard mask (HM) 112 and process 500-4 for removing polymer brush 508 from inorganic HM 112, according to some embodiments of the present disclosure. In process 500-3, polymer brush 508 is spin-coated onto inorganic HM 112 and subsequently baked at approximately 150 °C for approximately 1 minute. The baking promotes the covalent bonding of the alkyne-graft group 314 on polymer brush 508 to inorganic HM 112. Once polymer brush 508 is attached, subsequent preparation steps (e.g., photoresist coating and lithographic patterning) can be performed. In process 500-4, polymer brush 508 is removed from inorganic HM 112 Cause to crack In process 500-3, polymer brush 508 is spin-coated onto inorganic HM 112 and subsequently baked at approximately 150 °C for approximately 1 minute. The baking promotes the covalent bonding of the alkyne-graft group 314 on polymer brush 508 to inorganic HM 112. Once polymer brush 508 is attached, subsequent preparation steps (e.g., photoresist coating and lithographic patterning) can be performed. In process 500-4, polymer brush 508 is removed from inorganic HM 112 Cause to crackTo sever the bond between the grafting group 314 and the remainder of the polymer brush 508, a combination of acid (H+) and heat is applied to the attached polymer brush 508. The residual polymer 504 can then be rinsed away with an organic solvent.

[0045] The photolithography process using the polymer brush 104 disclosed herein can be used in the manufacture of integrated circuit chips for use in electronic devices. These integrated circuit chips are distributed by manufacturers as raw wafers, bare dies, those packaged in single-chip form (e.g., plastic carriers with leads attached to a motherboard or other carrier), those packaged in multi-chip form (e.g., ceramic carriers with surface interconnects or buried interconnects or both), etc. The chips can be integrated with other chips, circuit elements, signal processing devices, etc. Examples of end products that can include the chips are computing devices (e.g., computer products including a display, keyboard or other input device, and a processor), toys, electrical products, automotive parts, etc.

[0046] In addition to improving the adhesion of the photoresist to the inorganic hard mask 112, silicon wafer 116, or other substrate, the polymer brush 104 disclosed herein can be used for other purposes. For example, the polymer brush 104 may be used to improve the adhesion between an inorganic surface and a non-photoresist polymer. The polymer brush 104 may also be used to improve the wettability of a surface, to prevent biofouling of a surface underwater, to improve the performance of ion beam etching, etc.

[0047] It should be noted that in some embodiments, the compounds described herein can contain one or more chiral centers. These can include racemic mixtures, diastereomers, enantiomers, and mixtures containing one or more stereoisomers. Further, the disclosed compounds can encompass the racemic forms of the compounds, in addition to the individual stereoisomers, and mixtures containing any of these. The temperature and time ranges indicated herein can include the temperatures or times at either end of the range, or any temperature or time between these boundaries.

[0048] The synthetic processes discussed herein and their accompanying drawings are illustrative examples and not limiting, and these can vary with reaction conditions, components, methods, etc. Additionally, the reaction conditions can be varied as appropriate during the course of the process. Further, in some embodiments, as would be understood by one of ordinary skill in the art, processes can be added or omitted while remaining within the scope of the disclosure.

Claims

1. A polymer brush comprising a plurality of repeating units, wherein the plurality of repeating units polymerize to form the polymer brush, at least a portion of the plurality of repeating units has one or more grafting groups for grafting to an inorganic substrate, wherein the grafting group is independently selected from the group consisting of alkyne, primary hydroxyl, secondary hydroxyl, epoxy, phosphonic acid, propargyl, amine, and alkoxysilane based on the properties of the inorganic substrate, at least a portion of the plurality of repeating units has one or more interfacial adjustment groups that mediate adhesion between the inorganic substrate and the photoresist, wherein the interfacial adjustment group is independently selected from the group consisting of phenol, sulfonic acid, fluorosulfonic acid, carboxylic acid, acrylic acid, methoxy group, ethylene group, and trifluoromethyl group based on the properties of the photoresist, and at least a portion of the plurality of repeating units has one or more cleavable groups, wherein the one or more cleavable groups are bonded to the one or more grafting groups, A polymer brush that mediates the interfacial interaction between the inorganic substrate and the photoresist.

2. The inorganic substrate includes a material selected from the group consisting of silicon, titanium nitride, titanium oxide, titanium oxynitride, tantalum nitride, hafnium oxide, niobium nitride, lanthanum oxide, silicon oxide, silicon oxynitride, zirconium oxide, and tin oxide The polymer brush according to claim 1.

3. A lithographic patterning process, providing an inorganic substrate, depositing the polymer brush according to claim 1 or 2 on the inorganic substrate, depositing a photoresist on the polymer brush, masking the photoresist using a photomask having a pattern, irradiating energy from an energy source to the masked photoresist, developing the photoresist to form the etch mask having the pattern, etching a portion of the inorganic substrate exposed by the etch mask, comprising a process.

4. The process according to claim 3, wherein the energy source is a laser-driven tin plasma.

5. The process according to claim 3, wherein the energy is extreme ultraviolet light.

6. The process according to claim 3, wherein the photoresist is an acrylic photoresist or a phenolic photoresist.

7. The process according to claim 3, wherein the photoresist is a hybrid photoresist.

8. The process according to claim 3, wherein the inorganic substrate is an ultra-thin inorganic hard mask.

9. The process according to claim 3, wherein the inorganic substrate comprises a material selected from the group consisting of silicon, titanium nitride, titanium oxide, titanium oxynitride, tantalum nitride, hafnium oxide, niobium nitride, lanthanum oxide, silicon oxide, silicon oxynitride, zirconium oxide, and tin oxide.

10. A method for manufacturing an electronic device, comprising: providing an inorganic substrate; depositing the polymer brush according to claim 1 or 2 on the inorganic substrate; depositing a photoresist on the polymer brush; masking the photoresist using a photomask having a pattern; irradiating the masked photoresist with extreme ultraviolet light; developing the photoresist to form an etch mask having the pattern; etching a portion of the inorganic substrate exposed by the etch mask; and the method for manufacturing an electronic device.

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