Modification method of polyalkylene ether, thioether modified polyether derivative and application

Abstract

The invention belongs to the technical field of integrated circuit manufacturing, and particularly relates to a modification method of polyalkylene ether, a thioether modified polyether derivative prepared by the method, and application of the thioether modified polyether derivative as an inhibitor in an electroplating solution in electroplating filler metal in an interconnection structure. According to the method provided by the invention, an active double bond is introduced to one end of polyether by virtue of a nucleophilic substitution reaction of polyether hydroxyl and allyl halide, then a sulfur-containing group is efficiently and accurately introduced to an ether chain by virtue of a sulfydryl-alkene click reaction, and the prepared thioether modified polyether derivative can be used as an inhibitor to be applied to acidic copper plating; the inhibitor is particularly suitable for defect-free filling of metal interconnect structures with small size pore diameters or high aspect ratio features.

Description

Technical Field

[0001] This application belongs to the technical field of integrated circuit manufacturing, and particularly relates to a method for modifying polyalkylene ether, a thioether-modified polyether derivative prepared by the foregoing method, and the application of such a thioether-modified polyether derivative as an inhibitor in an electroplating solution in the electroplating of metal interconnect structures. Background Art

[0002] With the increase in circuit frequency and the decrease in scale, the main material for metal interconnects in the integrated circuit industry has changed from aluminum to copper with lower resistivity and higher electromigration resistance. Due to the problem that copper is difficult to etch, in 1997, IBM announced the introduction of the copper damascene technology in the production line and developed a copper electrodeposition technology for manufacturing metal interconnect structures.

[0003] Compared with planar electroplating, there are problems such as uneven current distribution and plating solution mass transfer in narrow interconnect holes. Therefore, defect-free filling of feature structures such as vias or trenches is one of the technical difficulties in semiconductor electroplating. The most ideal filling must ensure that copper is preferentially deposited in deep holes, which requires the introduction of organic additives into the electroplating solution and the use of the characteristics of different diffusion rates of accelerators and inhibitors for filling hole electroplating. The diffusion rate of the inhibitor is slower than that of the accelerator. The main action areas are the upper part of the sidewall of the via or trench and the outer surface of the hole, while the accelerator generally easily enters the bottom of the trench and via for adsorption, making the deposition rate at the bottom of the hole fast, and the deposition rates of the sidewall and the top are relatively inhibited, so that the copper deposition rate at the bottom of the hole is higher than that on the surface, and then the filling of copper in the hole from bottom to top is realized. In this process, maintaining an appropriate antagonistic effect between the inhibitor and the accelerator is crucial for achieving void-free filling of feature structures.

[0004] Traditional "inhibitors" are usually polyether compounds, generally long-chain polyalkylene glycols, such as high molecular weight polyethylene glycol (PEG), poly-1,2-propanediol (PPG), or polyalkylene oxides, such as block copolymers of ethylene oxide (EO) and propylene oxide (PO). The polyalkylene oxide chain segment can adsorb on the copper cathode surface to form a film, which polarizes the copper deposition potential of electroplated copper and can reduce the copper deposition rate (under the same overpotential), so it is called an inhibitor. There is a competitive adsorption relationship between the accelerator and the inhibitor on the copper surface. The ability of the inhibitor to resist replacement by the accelerator will affect the feature filling performance by influencing the sidewall growth. Traditional polyether inhibitors are mainly adsorbed on the copper surface through the bridging action of chloride ions and will be gradually replaced by the accelerator during the electro-deposition process, and the ability to resist replacement by the accelerator is weak. Therefore, it is usually necessary to add a high concentration of polyether inhibitors (usually 100 mg / L to 200 mg / L) to ensure effective inhibition at the sidewalls of the features during the deposition process and prevent premature sealing.

[0005] As the chip integration level becomes higher and higher, the hole size of feature structures such as vias or trenches is further reduced, and the risk of premature closing of the sidewalls of the features to form pinched voids increases accordingly. In particular, it is necessary to suppress the deposition of copper on the sidewalls of the features. The stronger the ability of the inhibitor to resist the replacement of the accelerator, the more effective it is in suppressing the growth of copper on the sidewalls. The method of improving the inhibition ability of traditional polyether inhibitors by increasing the addition concentration no longer works, and it is necessary to find an inhibitor that can more effectively suppress the copper deposition on the sidewalls of the features. Although many researchers have developed new inhibitors for the filling of features with extremely small orifice sizes and / or high aspect ratios. For example, amine-initiated polyalkylene oxide copolymer inhibitors provide strong cathodic adsorption ability by a polyamine core structure; or copolymerization of vinyl monomers containing O and / or N and vinyl monomers of polyethers. These methods have problems with greater difficulty in regulating the molecular weight and structure. Therefore, it is still necessary to develop inhibitors based on other functional groups, with adjustable structures and super-filling characteristics to meet more stringent electroplating filling requirements. Summary of the Invention

[0006] The purpose of this application is to provide a modification method of polyalkylene ether, a thioether-modified polyether derivative prepared by the foregoing method, and the application of this thioether-modified polyether derivative as an inhibitor in an electroplating solution in the electroplating of metal interconnect structures, aiming at the deficiencies of the above-mentioned prior art.

[0007] To solve the above technical problems, the first aspect of this application provides a modification method of polyalkylene ether, including the following steps:

[0008] (1) Allylation of polyalkylene ether: Mix the polyalkylene ether shown in formula (I) and an alkaline substance evenly in an organic solvent I, heat to 25-100 °C, and slowly dropwise add allyl halide during the heating process to carry out an allylation reaction for 2-16 hours to obtain allylated polyalkylene ether;

[0009]

[0010] In formula (I), R 1 is selected from H, alkyl, optionally substituted arylalkyl or aryl;

[0011] In formula (I), each (OCHR 2 CHR 3 ) unit is independently the same or different, and R 2 , R 3 are independently selected from H, methyl or ethyl;

[0012] n is 3-300;

[0013] (2) The allylated polyalkylene ether reacts with a thiol to obtain a thioether-modified polyether derivative: Dissolve the allylated polyalkylene ether and the dithiol compound shown in formula (II) in an organic solvent II, add an initiator, displace the air in the reaction flask with high-purity nitrogen, and initiate the thiol-ene click reaction by photoinitiation or thermal initiation. After the reaction is completed and purified, a thioether-modified polyether derivative is obtained;

[0014] HS-Z-SH (II)

[0015] In formula (II), the spacer Z is a divalent organic group containing at least one carbon atom, and Z is independently selected from substituted or unsubstituted straight-chain C2-C12 alkyl groups, branched C3-C6 alkyl groups, C6-C10 cycloalkyl groups, arylalkyl groups, aryl groups or heterocyclic groups; and the alkyl groups and arylalkyl groups are optionally doped with one or more heteroatoms selected from O, N and S.

[0016] Preferably, in the method for modifying a polyalkylene ether provided by the present invention, R 1 is selected from H, methyl, ethyl or benzyl.

[0017] Preferably, in the method for modifying a polyalkylene ether provided by the present invention, in step (1), the allyl halide is allyl bromide or allyl chloride; the basic substance is sodium hydroxide, potassium hydroxide, calcium oxide or potassium carbonate.

[0018] Preferably, in the method for modifying a polyalkylene ether provided by the present invention, in step (1), the molar ratio of the polyalkylene ether to the allyl halide fed is 1:1 to 1.5:1; the molar ratio of the allyl halide to the basic substance fed is 0.5:1 to 1.5:1.

[0019] Preferably, in the method for modifying a polyalkylene ether provided by the present invention, the organic solvent I is selected from one or more of tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol monomethyl ether, N,N-dimethylformamide, methanol, ethanol, and isopropanol.

[0020] Preferably, in the method for modifying a polyalkylene ether provided by the present invention, in step (2), the molar ratio of the dithiol compound to the allylated polyalkylene ether fed is 1:2 to 1:3.

[0021] Preferably, in the method for modifying a polyalkylene ether provided by the present invention, in step (2), the thiol-ene click reaction is thermally initiated, and the initiator is selected from at least one of peroxides (such as lauroyl peroxide, benzoyl peroxide, tert-butyl perbenzoate), azo compounds (such as azobisisobutyronitrile, azobisisoheptonitrile, azobisisobutyramidine hydrochloride), and the amount of the initiator is 0.1 wt.% to 5.0 wt.% of the total mass of the reaction system; the temperature of the initiated thiol-ene click reaction is 30 to 120 °C, and the reaction time is 0.5 to 10 hours; the organic solvent II is selected from at least one of tetrahydrofuran, dichloromethane, acetone, ethanol, methanol, and chloroform.

[0022] Preferably, in the method for modifying a polyalkylene ether provided by the present invention, in step (2), the thiol-ene click reaction is photo-initiated, and the initiator is selected from at least one of dimethoxybenzene, 2-hydroxy-2-methyl-1-phenyl-1-propanone, (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone, and 2,2-dimethoxyacetophenone. The amount of the initiator is 1 wt.% to 3 wt.% of the total mass of the reaction system; the temperature of the initiated thiol-ene click reaction is 0 to 80 °C; the irradiation time of the ultraviolet lamp is 0.5 - 5 hours; the ultraviolet light irradiation intensity is 0.1 to 2.0 mW / cm 2 ; the organic solvent II is selected from at least one of tetrahydrofuran, dichloromethane, acetone, ethanol, methanol, and chloroform.

[0023] The second aspect of the present invention provides a thioether-modified polyether derivative, which is prepared by the method for modifying a polyalkylene ether provided by the first aspect of the present invention.

[0024] The third aspect of the present invention provides an electroplating additive composition, which contains at least one inhibitor, and the inhibitor is the thioether-modified polyether derivative described in the second aspect of the present invention.

[0025] Preferably, the electroplating additive composition provided by the present invention further contains at least one accelerator and at least one leveling agent; the accelerator is sodium poly(dithiopropane sulfonate) or 3-mercapto-1-propanesulfonate; the leveling agent is polyethyleneimine, a polyethyleneimine derivative, a polyquaternary ammonium salt, an amino acid, or a polypeptide derivative.

[0026] The fourth aspect of the present invention provides an electroplating solution, which contains the electroplating additive composition described in the third aspect of the present invention and a basic plating solution. Among them, the concentration of the inhibitor is 1 to 200 mg / L, the concentration of the accelerator is 1 to 100 mg / L, and the concentration of the leveling agent is 1 to 50 mg / L; the basic plating solution contains metal ions, an acidic electrolyte, and halide ions.

[0027] The fifth aspect of the present invention provides the application of the electroplating solution described in the fourth aspect in the electroplating of metal interconnect structures. Among them, the metal interconnect structure has nano- or micro-scale pore diameters, and the substrate of the metal interconnect structure is selected from damascene process chips, through-silicon via (TSV) interposers, redistribution layers, substrates, or printed circuit boards.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. The method for modifying polyalkylene ether provided by the present invention utilizes the nucleophilic substitution reaction between polyether hydroxyl groups and allyl halides to introduce active double bonds at one end of the polyether, and then introduces sulfur-containing groups efficiently and precisely on the ether chain through thiol-ene click reaction. The preparation route is simple and controllable, avoiding the uncontrollable problem of the ring-opening polymerization process of epoxy monomers commonly used in polyether modification. Moreover, on the basis of controllable polyether chain length and block ratio, the number of introduced thioether functional groups and corresponding properties can be flexibly designed and regulated, providing a new strategy for enriching and regulating the properties of thioether-modified polyether derivatives.

[0030] 2. The thioether-modified polyether derivative prepared according to the method provided by the present invention can be used as an inhibitor in acid copper plating. This inhibitor contains both thioether groups that can interact with the copper plating surface and polyoxyalkylene long-chain segments. While retaining the strong cathodic polarization effect of traditional polyether inhibitors, it also has strong anti-accelerator desorption ability, enabling it to significantly inhibit the growth of sidewall copper while ensuring the bottom-up growth of copper inside the feature, especially suitable for defect-free filling of small-size pore diameters and / or high aspect ratio features. And due to its high-efficiency strong inhibition ability, the required addition amount in the electroplating solution is significantly reduced compared with the addition amounts of other common inhibitors in the prior art.

[0031] 3. The preparation method provided by the present invention uses raw materials that are all commercial products and have a wide source. The preparation route is simple and the process is easy to control. The inhibition effect of the prepared thioether-modified polyether derivative can be adjusted by selecting raw materials with different structures and molecular weights to provide void-free metal filling on substrates with different scale features, having good industrial application value. Description of the Drawings

[0032] Figure 1 SEM image of the chip trench electroplated and filled in Example 5 (S-1 as inhibitor 50 mg / L) (feature diameter is about 45 nm);

[0033] Figure 2 SEM image of the chip trench electroplated and filled in Example 6 (S-1 as inhibitor 25 mg / L) (feature diameter is about 45 nm);

[0034] Figure 3SEM image of the chip trench electroplated and filled in Example 7 (S-2 as inhibitor at 50 mg / L); the characteristic diameter is about 45 nm.

[0035] Figure 4 SEM image of the chip trench electroplated and filled in the comparative example (L64 as inhibitor at 50 mg / L); the characteristic diameter is about 45 nm. Detailed implementation manners

[0036] In order to better understand the purpose, features and advantages of the present invention, the implementation manners of the present invention will be described in detail below with reference to the accompanying drawings. Unless otherwise specified, the materials used are all conventional products that can be obtained commercially. The description of the exemplary implementation manners is for illustrative purposes only and is not intended to limit the present invention and its applications.

[0037] Method for modifying polyalkylene ether

[0038] The implementation manners of the present application provide a method for modifying a polyalkylene ether, including the following steps:

[0039] (1) Allylation of the polyalkylene ether: The polyalkylene ether shown in formula (I) and a basic substance are uniformly mixed in an organic solvent I, and heated to 25-100 °C, preferably 40-80 °C. During the heating process, an allyl halide is slowly added dropwise to carry out an allylation reaction, and the reaction time is 2-16 hours, preferably 4-10 hours. After the reaction is completed and purified, an allylated polyalkylene ether is obtained;

[0040]

[0041] In formula (I), R 1 is selected from H, an alkyl group, an optionally substituted arylalkyl group or an aryl group, preferably H, methyl, ethyl or benzyl; each (OCHR 2 CHR 3 ) unit is independently the same or different, and R 2 , R 3 are independently selected from H, methyl or ethyl; n is 3-300;

[0042] (2) Reacting the allylated polyalkylene ether with a thiol to obtain a thioether-modified polyether derivative: The allylated polyalkylene ether and the dithiol compound shown in formula (II) are dissolved in an organic solvent II, an initiator is added, and the air in the reaction flask is replaced with high-purity nitrogen, and a thiol-ene click reaction is initiated by light or heat. After the reaction is completed and purified, a thioether-modified polyether derivative is obtained;

[0043] HS-Z-SH (II)

[0044] In formula (II), the spacer group Z is a divalent organic group containing at least one carbon atom, and Z is independently selected from substituted or unsubstituted straight-chain C2-C12 alkyl groups, branched C3-C6 alkyl groups, C6-C10 cycloalkyl groups, arylalkyl groups, aryl groups or heterocyclic groups; and the alkyl groups and arylalkyl groups are optionally doped with one or more heteroatoms selected from O, N and S.

[0045] In some embodiments of the present application, is a polymer of one or more alkylene oxides, which is also referred to as "polyalkylene oxide" in this application document. Corresponding alkylene oxide examples include ethylene oxide, propylene oxide, and butylene oxide, and preferably a copolymer of ethylene oxide and propylene oxide; and the ethylene oxide content in the polyalkylene oxide group is preferably 10 wt.% - 90 wt.%, more preferably 30 wt.% - 70 wt.%. Among them, the polyalkylene oxide group can be a block, random or alternating structure or a combination thereof.

[0046] In some embodiments of the present application, is a poly(ethylene oxide) (PEO) / poly(propylene oxide) (PPO) block, and such blocks can include, but are not limited to: -PEO-PPO-, -PPO-PEO-, -PEO-PPO-PEO-, -PPO-PEO-PPO-, etc. The preferred block type is -PEO-PPO-PEO-, and the weight ratio of PEO to PPO therein is preferably 15:85 to 85:15, more preferably 40:60 to 70:30.

[0047] In some embodiments of the present application, the polyalkylene ether shown in formula (I) is selected from conventional polyalkylene oxide inhibitors in the art, including polyalkylene ethers with hydroxyl groups at both ends (wherein R 1 is H) and polyalkylene ethers with an ether-capped end (wherein R 1 is an alkyl group, an arylalkyl group or an aryl group). The corresponding alkylene oxides are preferably selected from ethylene oxide, propylene oxide, and butylene oxide, especially ethylene oxide and propylene oxide. Preferably, the arrangement of ethylene oxide and propylene oxide shown in formula (I) can be block, gradient or random. Such compounds are generally known, commercially available, and can be used without further purification, such as the trade name "PLURONIC", which is available from BASF.

[0048] In some embodiments of the present application, the propylene oxide units in the polyalkylene ether account for 10 wt.% - 30 wt.% of the total polyalkylene oxide segment. Preferably, the weight-average molecular weight of the polyalkylene ether is 400 g / mol - 100,000 g / mol, more preferably 1,000 g / mol - 15,000 g / mol.

[0049] In some embodiments of the present application, examples of the polyalkylene ether (I) are polypropylene glycol, polyethylene glycol, polyoxyethylene / polyoxypropylene copolymer, polyoxyethylene / polyoxybutylene copolymer, etc.

[0050] In some embodiments of the present application, the allyl halide is allyl bromide or allyl chloride; the basic substance is sodium hydroxide, potassium hydroxide, calcium oxide or potassium carbonate.

[0051] In some embodiments of the present application, the molar ratio of the polyalkylene ether to the allyl halide in the feed is 1:1 to 1.5:1; the molar ratio of the allyl halide to the basic substance in the feed is 0.5:1 to 1.5:1.

[0052] In some embodiments of the present application, the organic solvent I is selected from one or more of tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol monomethyl ether, N,N-dimethylformamide, methanol, ethanol, isopropanol, and preferably tetrahydrofuran.

[0053] In some embodiments of the present application, Z is an unbranched or branched C2-C12 alkylene group, and most preferably a C2-C6 straight-chain alkylene group.

[0054] In some embodiments of the present application, Z contains a heteroatom, and the dithiol compound represented by formula (II) may be a compound of formula (II-a):

[0055]

[0056] In formula (II-a), each R 4 is independently selected from H, a straight-chain or branched C1-C12 alkyl group; R 4 is preferably H or a C1-C5 alkyl group, more preferably H or a C1-C3 alkyl group. When R 4 is an alkyl group, it may be optionally substituted by a hydroxyl group or an alkoxy group. Each Q is independently selected from O, S, NR 5 , R 5 is selected from H and a straight-chain or branched C1-C12 alkyl group. a is an integer from 2 to 20, preferably 2 to 8; b is an integer from 0 to 20, preferably 0 to 8; c is an integer from 2 to 20, preferably 2 to 10.

[0057] In another part of the embodiments of the present application, the dithiol compound represented by formula (II) may be a compound of formula (II-b):

[0058] HS-R 6 -Y-R 6 -SH (II-b)

[0059] In formula (II-b), each R 6Preferably, it is a C1-C8 alkylene or a C2-C6 alkyleneoxy; Y is an optionally substituted arylene, cycloalkylene or nitrogen-containing heterocycle.

[0060] In some embodiments of the present application, Y in formula (Ⅱ-b) is a C6-C15 arylene, including but not limited to phenyl, naphthyl, pyridyl, methylphenyl and diphenylmethyl, and the aryl group may be optionally substituted by an alkyl, an alkoxy or a halogen.

[0061] In another part of the embodiments of the present application, Y in the general formula (Ⅱ-b) is a C6-C15 cycloalkylene, which can be a monocyclic, spiro, fused or bridged bicyclic.

[0062] In still another part of the embodiments of the present application, Y in the general formula (Ⅱ-b) can be an aromatic or non-aromatic heterocycle, which may have S, N or O, and the heterocycle includes but not limited to imidazole, triazole, benzimidazole, purine, piperazine, pyrazole, triazine, thiazole, thiadiazole, dithiane, thiophene, and the heterocycle may be optionally substituted by a hydroxyl group, an alkyl or an alkoxy.

[0063] More specifically, the dithiols in the embodiments of the present application include but not limited to: aliphatic dithiol compounds such as dimercaptomethane, 1,2-ethanedithiol, 1,2-propanedithiol, 1,3-propanedithiol, 1,3-dimercapto-2-methylpropane, 1,3-butanedithiol, 1,4-butanedithiol, 2,3-butanedithiol, 1,3-pentanedithiol, 1,5-pentanedithiol, 1,6-hexanedithiol, 1,3-dimercapto-3-methylbutane, 1,3-dimercapto-2-methylbutane, 1,2-cyclohexanedithiol, 2,2'-thiobis(ethanethiol), 1,8-dimercapto-3,6-dithiaoctane, 2,5-bis(methylthiol)-1,4-dithiane, 1,8-dimercapto-3,6-dioxaoctane, 1,5-dimercapto-3-oxapentane, etc.; aromatic dithiol compounds such as 1,4-benzenedithiol, 1,4-benzenedimethanethiol; heterocyclic dithiol compounds such as 2,5-dimercapto-1,3,4-thiadiazole, 2,5-thiophenedithiol.

[0064] In some embodiments of the present application, the molar ratio of the dithiol compound to the allylated polyalkylene ether fed is 1:2 to 1:3.

[0065] In some embodiments of the present application, the thiol-ene click reaction is thermally initiated: the initiator is selected from peroxides (such as lauroyl peroxide, benzoyl peroxide, tert-butyl perbenzoate), azo compounds (such as azobisisobutyronitrile, azodiisooctanenitrile, azobisisobutyr amidine hydrochloride), or a mixture of one or more of them. The amount of the initiator is 0.1 wt.% to 5.0 wt.%, preferably 0.1 wt.% to 1.0 wt.%, of the total mass of the reaction system; the temperature of the initiated thiol-ene click reaction is 30 to 120 °C, preferably 40 to 90 °C; the reaction time is 0.5 to 10 hours, preferably 2 to 6 hours; the organic solvent II is selected from one or more of tetrahydrofuran, dichloromethane, acetone, ethanol, methanol, chloroform; preferably ethanol.

[0066] In some embodiments of the present application, the thiol-ene click reaction is photo-initiated: the initiator is selected from one or more of dimethoxybenzyl, 2-hydroxy-2-methyl-1-phenyl-1-propanone, (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxyacetophenone, and the amount of the initiator is 1 wt.% to 3 wt.% of the total mass of the reaction system; the temperature of the initiated thiol-ene click reaction is 0 to 80 °C, preferably 0 to 40 °C; the irradiation time of the ultraviolet lamp is 0.5 - 5 hours, preferably 1 to 3 hours; the ultraviolet light irradiation intensity is 0.1 to 2.0 mW / cm 2 ; the organic solvent II is one or more of tetrahydrofuran, dichloromethane, acetone, ethanol, methanol, chloroform, and preferably ethanol.

[0067] Electroplating additive composition

[0068] The embodiments of the present application also provide an electroplating additive composition, which contains at least one inhibitor, and the inhibitor is a thioether-modified polyether derivative prepared in the above embodiments of the present application.

[0069] In some embodiments of the present application, the electroplating additive composition further contains at least one accelerator and at least one leveler.

[0070] The accelerator can be a conventional accelerator in the art, including but not limited to sulfur-containing organic compounds and / or salts, such as compounds with sulfonic acid groups and their salts, mercaptans, and phosphates. The accelerator is preferably one or a combination of several of sodium polydithiopropane sulfonate (SPS), sodium 3-mercapto-1-propanesulfonate (MPS), sodium N,N-dimethyldithiocarbony propane sulfonate (DPS), isothiourea propane sulfonic acid inner salt (UPS), sodium phenyl dithiopropane sulfonate (BSP), and sodium 3-(benzothiazol-2-ylthio)propane sulfonate (ZPS). The particularly preferred accelerators are SPS and MPS. The content of the accelerator in the electroplating solution is preferably 1-100 mg / L, more preferably 1-30 mg / L.

[0071] The leveling agent can be a conventional leveling agent in the art. Preferably, the leveling agent is freely selected from nitrogen-containing compounds, such as polyethyleneimine, polyethyleneimine derivatives, polyquaternary ammonium salts, dyes, amino acids, or polypeptide derivatives. The content of the leveling agent in the electroplating solution is preferably 1-50 mg / L, more preferably 1-10 mg / L.

[0072] In some embodiments of the present application, the electroplating additive composition may also selectively use additional suitable inhibitors, including but not limited to ethylene oxide copolymers, especially ethylene oxide and propylene oxide copolymers. The ethylene oxide and propylene oxide of the suitable inhibitor can be block, alternating, gradient, or random arrangements.

[0073] Generally, the higher the proportion of the hydrophobic PPO block in the polyether chain, the stronger its cathodic polarization ability, but it will also reduce the solubility of the polymer molecule in water. For the thioether-modified polyether derivative of the present invention, the adsorption performance can be adjusted by adjusting the ratio of the hydrophobic group PPO to the hydrophilic group PEO in the polyether chain segment of the structure, so as to control its inhibitory effect during the metal electrodeposition process. Since the raw material polyether (Ⅰ) used in the preparation of the present invention has a wide source, polyalkylene ethers with different structures and molecular weights can mostly be obtained commercially. Therefore, the inhibitory effect of the prepared thioether-modified polyether derivative can be adjusted by selecting polyalkylene ether raw materials with different structures and molecular weights to match different application scenarios.

[0074] Electroplating solution

[0075] The embodiments of the present application also provide an electroplating solution, which comprises the electroplating additive composition described in the above embodiments of the present invention and a base plating solution.

[0076] In some embodiments of the present application, the concentration of the inhibitor is 1 to 200 mg / L, the concentration of the accelerator is 1 to 100 mg / L, and the concentration of the leveling agent is 1 to 50 mg / L. According to the experimental examples provided in the later part of the present application, compared with the inhibitors commonly used in other metal electroplating solutions in the art, the addition amount required for the thioether-modified polyether derivative inhibitor provided by the present application is significantly lower.

[0077] In some embodiments of the present application, the base plating solution contains metal ions, an acidic electrolyte, halide ions, and water.

[0078] In some embodiments of the present application, the metal ions may be copper salts, including but not limited to one or more of copper sulfate, copper chloride, copper acetate, copper nitrate, copper fluoroborate, copper methyl sulfonate, and copper p-toluenesulfonate, preferably copper sulfate. The content of copper ions in the electroplating solution is 5 to 110 g / L, preferably 30 to 80 g / L. These copper ion salts are generally commercially available.

[0079] In some embodiments of the present application, the acidic electrolyte may be one or more of sulfuric acid, acetic acid, methylsulfonic acid, and toluenesulfonic acid, preferably sulfuric acid. The acid content in the electroplating solution is preferably 1 to 250 g / L, more preferably 5 to 50 g / L.

[0080] In some embodiments of the present application, the halide ion is preferably a chloride ion, and the chloride ion is preferably selected from hydrochloric acid and copper chloride. The concentration of halide ions in the electroplating solution is preferably 10 to 100 mg / L, more preferably 30 to 80 mg / L.

[0081] Application

[0082] Some embodiments of the present application also provide the application of the above electroplating solution containing the thioether-modified polyether derivative in the electroplating of a substrate metal interconnect structure to achieve defect-free and high-quality electroplating of integrated circuit interconnect trenches / vias.

[0083] The general method for electroplating copper on a substrate can refer to any method known in the prior art and literature. In most cases, it is preferred that the substrate contains a metal seed layer for initial plating thereon, and more preferably a copper seed layer. A metal layer is deposited inside and on the surface of the trench structure of the substrate by electroplating.

[0084] By way of example, the application implementation includes the following steps:

[0085] (1) Provide an electroplating solution containing the thioether-modified polyether derivative, and bring the substrate to be electroplated into contact with the electroplating solution composition;

[0086] (2) Apply a current to the substrate to be electroplated for electroplating.

[0087] In the above step (1), the substrate can be a substrate with nano- and micro-scale pore trenches and through-holes commonly used in the art. For example, a damascene process chip, a through-silicon via (TSV) interposer, a redistribution layer, a substrate, a printed circuit board, etc., preferably a damascene process chip.

[0088] In the above step (2), the current density can vary with the specific substrate to be plated. Generally, the anode and cathode current densities can vary in the range of 0.1 - 10 ASD, and the preferred current density is in the range of 0.1 - 6 ASD. Usually, multi-step electroplating is used during actual electroplating, and the current applied can be direct current, pulsed current, pulse reverse current, or other suitable currents.

[0089] In addition, the electroplating solution temperature is maintained in the range of 10 - 65 °C, more preferably 20 - 30 °C. The electroplating solution is stirred during the electroplating operation to keep the electroplating solution uniform during electroplating.

[0090] The key to filling small-size pores and / or high-aspect-ratio trenches and through-holes by electro-depositing copper lies in that the copper deposition rate in the vertical direction within the pores must be much greater than the deposition rate in the horizontal direction, the copper deposition on the sidewalls of the through-holes needs to be inhibited, and at the same time, the speed of copper deposition from bottom to top within the pores should be increased as much as possible.

[0091] The inhibitor prepared by the present invention has a thioether structure with strong adsorption. Specific galvanostatic test examples (see the following "Examples") show that compared with the commonly used inhibitor PEO-PPO-PEO block copolymer L64 in the art, the inhibitor provided by the present invention has strong adsorption on the cathode and exhibits excellent ability to resist the desorption of accelerators. The acidic composition of this inhibitor can ensure a relatively high copper deposition rate from bottom to top within the pores, while effectively inhibiting the copper deposition on the upper part of the pore walls. Specific electroplating examples (see the following "Examples") also show that the electroplating additive composition containing the inhibitor of the present invention is particularly suitable for filling small-diameter pores and / or high-aspect-ratio trenches / through-holes, and there are basically no defects such as pores and voids in the copper plating, especially those with a pore diameter size less than 50 nm or smaller. In addition, compared with the known acidic aqueous compositions in this field, the addition amount of the inhibitor in the copper deposits of the present invention is significantly lower.

[0092] Example 1

[0093] Synthesis of inhibitor S-1 (thioether-modified polyether derivative according to the present invention):

[0094] Step 1: Dissolve 9.50 g (5 mmol) of PEO-PPO-PEO block copolymer (Mw = 1900 g / mol, EO content 44 wt.%) and 0.28 g (5 mmol) of potassium hydroxide in 20 mL of anhydrous tetrahydrofuran, and heat to 60 °C with stirring. Subsequently, slowly add 0.60 g (5 mmol) of allyl bromide within 8 h, and react at this temperature for 6 h. After the reaction is completed, remove tetrahydrofuran by rotary evaporation under reduced pressure, dissolve with dichloromethane, wash with water 1 - 3 times, and then remove dichloromethane by rotary evaporation to obtain a mono-allylated PEO-PPO-PEO copolymer (block intermediate). 1 H NMR (400 MHz, DMSO-d 6 , δ): 5.87 (m, 1H), 5.25 (d, 1H), 5.14 (d, 1H), 3.93 (d, 2H), 3.34 - 3.81 (m, 130H), 1.04 (d, 55H).

[0095] Step 2: Take 7.76 g (4 mmol) of the block intermediate obtained in Step 1 and 0.36 g (2 mmol) of 2,2'-(1,2-ethanediyl dioxy)bis(ethanethiol) and dissolve them in 15 mL of anhydrous ethanol, and add 0.08 g of azobisisobutyronitrile. Then evacuate, displace the air in the reaction flask with high-purity nitrogen, and after completion, heat to 50 °C and react for 1 h, react at 70 °C for 2 h, and finally raise the temperature to 90 °C and react for 1 h. After the reaction is completed, remove ethanol by rotary evaporation to obtain a pale yellow viscous liquid (S-1). 1 H NMR (400 MHz, DMSO-d 6 , δ): 3.34 - 3.81 (m, 273H), 2.63 (t, 4H), 2.55 (t, 4H), 1.73 (m, 4H), 1.04 (d, 111H).

[0096]

[0097] Example 2

[0098] Synthesis of inhibitor S-2 (thioether-modified polyether derivative according to the present invention):

[0099] Step 1: Dissolve 5.50 g (5 mmol) of PEO-PPO-PEO block copolymer (Mw = 1100 g / mol, EO content 12 wt.%) and 0.28 g (5 mmol) of potassium hydroxide in 20 mL of anhydrous tetrahydrofuran, and heat to 60 °C while stirring. Subsequently, slowly add 0.60 g (5 mmol) of allyl bromide within 8 h, and react at this temperature for 6 h. After the reaction is completed, remove tetrahydrofuran by rotary evaporation under reduced pressure, then dissolve with dichloromethane, wash with water 1 - 3 times, and then remove dichloromethane by rotary evaporation to obtain monoallylated PEO-PPO-PEO copolymer (block intermediate). 1 H NMR (400 MHz, DMSO-d 6 , δ): 5.87 (m, 1H), 5.25 (d, 1H), 5.14 (d, 1H), 3.93 (d, 2H), 3.34 - 3.81 (m, 60H), 1.04 (d, 48H).

[0100] Step 2: Take 4.56 g (4 mmol) of the block intermediate obtained in Step 1 and 0.36 g (2 mmol) of 2,2'-(1,2-ethylenedioxy)bis(ethanethiol) and dissolve them in 10 mL of anhydrous ethanol, and add 0.05 g of azobisisobutyronitrile. Then evacuate, displace the air in the reaction flask with high-purity nitrogen, and after completion, heat to 50 °C and react for 1 h, react at 70 °C for 2 h, and finally raise the temperature to 90 °C and react for 1 h. After the reaction is completed, remove ethanol by rotary evaporation to obtain a pale yellow viscous liquid (S-2). 1 H NMR (400 MHz, DMSO-d 6 , δ): 3.14 - 3.80 (m, 132H), 2.62 (t, 4H), 2.55 (t, 4H), 1.73 (m, 4H), 1.03 (d, 96H).

[0101]

[0102] Example 3

[0103] Synthesis of inhibitor S-3 (thioether-modified polyether derivative according to the present invention):

[0104] Step 1: Dissolve 5.50 g (5 mmol) of polyethylene glycol (Mw = 1100 g / mol) and 0.28 g (5 mmol) of potassium hydroxide in 20 mL of anhydrous tetrahydrofuran, and heat to 60 °C while stirring. Subsequently, slowly add 0.60 g (5 mmol) of allyl bromide within 8 h, and react at this temperature for 6 h. After the reaction is completed, remove tetrahydrofuran by rotary evaporation under reduced pressure, then dissolve with dichloromethane, wash with water 1 - 3 times, and then remove dichloromethane by rotary evaporation to obtain monoallylated polyethylene glycol (intermediate). 11H NMR (400 MHz, D 2 2O, δ): 5.87 (m, 1H), 5.25 (d, 1H), 5.14 (d, 1H), 3.93 (d, 2H), 3.34 - 3.81 (m, 102H).

[0105] Step 2: Take 4.80 g (4 mmol) of the intermediate obtained in Step 1 and 0.36 g (2 mmol) of 2,2'-(1,2-ethylenedioxy)bis(ethanethiol), dissolve them in 15 mL of anhydrous ethanol, and add 0.05 g of azobisisobutyronitrile. Then evacuate, displace the air in the reaction flask with high-purity nitrogen. After completion, heat up to 50 °C and react for 1 h, then react at 70 °C for 2 h, and finally raise the temperature to 90 °C and react for 1 h. After the reaction, rotary evaporate to remove ethanol to obtain a pale yellow viscous liquid (S-3). 1 1H NMR (400 MHz, D 2 2O, δ): 3.51 - 3.80 (m, 216H), 2.79 (t, 4H), 2.67 (t, 4H), 1.88 (m, 4H).

[0106]

[0107] Example 4

[0108] Characterize the cathodic polarization ability and the interaction with the accelerator of the thioether-modified polyether derivative inhibitor and the reference inhibitor (the reference inhibitor is the PEO-PPO-PEO block copolymer L64) of the present invention through a constant current test:

[0109] Experimental setup: The composition of the test base solution is deionized water, 40 g / L copper ions (copper sulfate), 10 g / L sulfuric acid, and 50 mg / L chloride ions (hydrochloric acid). A current density of 2 ASD is applied to the working electrode in the base solution, and the stirring speed in the system is maintained at 350 rpm during the test. Inject the compound used as the inhibitor into the base solution at a concentration of 100 mg / L, and observe and record the potential drop caused by it (denoted as ΔE 1 ), then inject 25 mg / L of the accelerator SPS (sodium polydithiopropanesulfonate), and record the potential recovery amplitude (denoted as ΔE 2 ). The ratio ΔE 2 / ΔE 1 is used as the competitive desorption rate of the inhibitor and the accelerator. The smaller the competitive desorption rate value, the less likely it is for the inhibitor to be replaced by the accelerator. The results are shown in Table 1.

[0110] Table 1 Constant current test results

[0111]

[0112] As shown in Table 1, the compounds S-1, S-2, and S-3 obtained in the present invention, like the reference inhibitor L64, all have strong cathodic polarization ability, indicating that they can significantly reduce the local current density on the upper parts of the top surface and side walls where they play a major role, thereby increasing the local current density at the bottom of the feature where the inhibitory effect is relatively weak, and further increasing the "bottom-up" copper deposition rate within the feature. In addition, compared with L64, the competitive desorption rates of S-1, S-2, and S-3 with SPS are significantly reduced, indicating that the compounds S-1, S-2, and S-3 are not easily replaced by the accelerator SPS and can more effectively inhibit the copper deposition current density on the side walls of the feature when used as inhibitors. The results of the constant current test show that, compared with the commonly used electroplating inhibitor L64, the compounds S-1, S-2, and S-3 are more conducive to ensuring that the copper deposition rate at the bottom of the feature is greater than the combined rate of the side walls, which helps to achieve void-free filling of the feature.

[0113] Example 5

[0114] Acid copper plating example of the composition of the thioether-modified polyether derivative (S-1) according to the present invention:

[0115] The electroplating solution composition is: deionized water, 40 g / L copper ions (copper sulfate), 10 g / L sulfuric acid, 50 mg / L chloride ions (hydrochloric acid), 50 mg / L inhibitor S-1, 25 mg / L accelerator SPS (sodium poly(dithiopropane sulfonate)).

[0116] The complete electroplating process applies the electroplating current using a three-step method: electroplating for 11 s at 0.65 ASD, electroplating for 40 s at 1 ASD, and electroplating for 45 s at 6 ASD. The temperature of the electroplating solution is 20 - 30 °C, and while applying a constant current electroplating, the electroplating solution is stirred. Electroplating copper is carried out on a damascene process pattern wafer with a copper seed layer, which has grooves with an aspect ratio of approximately 3:1 and a feature diameter of 45 nm. The cross-section of the grooves in the electroplated chip is as Figure 1 , and the results show that after electroplating is completed, the feature is uniformly filled and no voids or seams appear.

[0117] Example 6

[0118] Acid copper plating example of the composition of the thioether-modified polyether derivative (S-1) according to the present invention:

[0119] The electroplating solution composition is: deionized water, 40 g / L copper ions (copper sulfate), 10 g / L sulfuric acid, 50 mg / L chloride ions (hydrochloric acid), 25 mg / L inhibitor S-1, 25 mg / L accelerator SPS (sodium poly(dithiopropane sulfonate)). The electroplating conditions are the same as those in Example 5.

[0120] The SEM image of the cross-section of the grooves in the electroplated chip is as Figure 2As shown, after observing multiple figures, the results show that the groove is evenly filled and there are no voids or seams.

[0121] Example 7

[0122] Example of acid copper plating of the composition of the thioether-modified polyether derivative (S-2) according to the present invention:

[0123] The electroplating solution composition is: deionized water, 40 g / L copper ions (copper sulfate), 10 g / L sulfuric acid, 50 mg / L chloride ions (hydrochloric acid), 50 mg / L inhibitor S-2, 25 mg / L accelerator SPS (sodium polydithiopropane sulfonate). The electroplating conditions are the same as those in Example 5.

[0124] By observing the cross-section of the groove in the chip obtained by electroplating through SEM, Figure 3 it shows that the groove is evenly filled and there are no voids or seams.

[0125] Comparative example (example not according to the present invention)

[0126] Repeat Example 7, but use the reference inhibitor L64 instead of the thioether-modified polyether derivative in the plating solution, and the example of acid copper plating of its composition. L64 is a commonly used inhibitor in the art that is commercially available.

[0127] The electroplating solution composition is: deionized water, 40 g / L copper ions (copper sulfate), 10 g / L sulfuric acid, 50 mg / L chloride ions (hydrochloric acid), 50 mg / L inhibitor L64, 25 mg / L accelerator SPS (sodium polydithiopropane sulfonate). The electroplating conditions are the same as those in Example 5.

[0128] The SEM image of the cross-section of the groove in the chip obtained by electroplating is as Figure 4 shown, and the results show that there are gaps or holes in the features, and defect-free filling cannot be achieved.

[0129] The above examples are only for illustrating the technical concept and characteristics of the present invention, and the purpose is to enable those who are familiar with this technology to understand the content of the present invention and implement it accordingly, and it cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for modifying a polyalkylene ether, characterized in that, it comprises the following steps: (1) Allylation of the polyalkylene ether: Mix the polyalkylene ether shown in formula (I) and an alkaline substance evenly in an organic solvent I, heat to 25-100 °C, slowly dropwise add allyl halide during the heating process, carry out the allylation reaction, and the reaction time is 2-16 hours to obtain allylated polyalkylene ether; In formula (I), R 1 is selected from H, alkyl, optionally substituted arylalkyl or aryl; (OCHR 2 CHR 3 ) units in formula (I) are each independently the same or different, and R 2 , R 3 are each independently selected from H, methyl or ethyl; n is 3-300; (2) React the allylated polyalkylene ether with a thiol to obtain a thioether-modified polyether derivative: Dissolve the allylated polyalkylene ether and the dithiol compound shown in formula (II) in an organic solvent II, add an initiator, displace the air in the reaction flask with high-purity nitrogen, and initiate the thiol-ene click reaction by photoinitiation or thermal initiation to obtain a thioether-modified polyether derivative; HS-Z-SH (II) In formula (II), the spacer Z is a divalent organic group containing at least one carbon atom, and Z is independently selected from substituted or unsubstituted linear C2-C12 alkyl, branched C3-C6 alkyl, C6-C10 cycloalkyl, arylalkyl, aryl or heterocyclic group; and the alkyl and arylalkyl are optionally doped with one or more heteroatoms selected from O, N and S.

2. The method for modifying a polyalkylene ether according to claim 1, characterized in that, In step (1), R 1 is selected from H, methyl, ethyl or benzyl.

3. The method for modifying a polyalkylene ether according to claim 1, characterized in that, In step (1), the allyl halide is selected from allyl bromide or allyl chloride; the alkaline substance is selected from sodium hydroxide, potassium hydroxide, calcium oxide or potassium carbonate.

4. The method for modifying a polyalkylene ether according to claim 1, characterized in that, In step (1), the molar ratio of the polyalkylene ether to the allyl halide charged is 1:1 to 1.5:1; the molar ratio of the allyl halide to the alkaline substance charged is 0.5:1 to 1.5:

1.

5. The method for modifying a polyalkylene ether according to claim 1, characterized in that, The organic solvent I is selected from at least one of tetrahydrofuran, ethylene glycol dimethyl ether, ethylene glycol monomethyl ether, N,N-dimethylformamide, methanol, ethanol, and isopropanol.

6. The method for modifying a polyalkylene ether according to claim 1, characterized in that, In step (2), the molar ratio of the dithiol compound to the allylated polyalkylene ether charged is 1:2 to 1:

3.

7. The method for modifying a polyalkylene ether according to claim 1, characterized in that, In step (2), the thiol-ene click reaction is thermally initiated, the initiator is selected from at least one of peroxides and azo compounds, and the dosage of the initiator is 0.1% - 5.0% of the total mass of the reaction system; the temperature of the initiated thiol-ene click reaction is 30-120 °C, and the reaction time is 0.5-10 hours; the organic solvent II is selected from at least one of tetrahydrofuran, dichloromethane, acetone, ethanol, methanol, and chloroform.

8. The method for modifying a polyalkylene ether according to claim 1, characterized in that, In step (2), the thiol-ene click reaction is photo-initiated, and the initiator is selected from at least one of benzoin dimethyl ether, 2-hydroxy-2-methyl-1-phenyl-1-propanone, (2,4,6-trimethylbenzoyl) diphenylphosphine oxide, 1-hydroxycyclohexyl phenyl ketone, and 2,2-dimethoxyacetophenone. The dosage of the initiator is 1% - 3% of the total mass of the reaction system; the temperature of the initiated thiol-ene click reaction is 0 - 80 °C; the ultraviolet lamp irradiation time is 0.5 - 5 hours; the ultraviolet light irradiation intensity is 0.1 - 2.0 mW / cm 2 ; the organic solvent two is selected from at least one of tetrahydrofuran, dichloromethane, acetone, ethanol, methanol, and chloroform.

9. A thioether-modified polyether derivative, characterized in that, it is prepared by the method according to any one of claims 1-8.

10. An electroplating additive composition comprising at least one inhibitor, characterized in that, the inhibitor is the thioether-modified polyether derivative described in claim 9.

11. The electroplating additive composition according to claim 10, characterized in that, it further comprises at least one accelerator and at least one leveler; the accelerator is selected from sodium polydithiopropane sulfonate or sodium 3-mercapto-1-propane sulfonate; the leveler is selected from polyethyleneimine, polyethyleneimine derivatives, polyquaternary ammonium salts, amino acids or polypeptide derivatives.

12. An electroplating solution, characterized in that, it comprises the electroplating additive composition described in claim 11 and a base plating solution, wherein the concentration of the inhibitor is 1 to 200 mg / L, the concentration of the accelerator is 1 to 100 mg / L, and the concentration of the leveler is 1 to 50 mg / L; the base plating solution contains metal ions, acidic electrolytes, and halide ions.

13. Use of the electroplating solution according to claim 12 in electroplating of metal interconnect structures.

14. The use according to claim 13, wherein the metal interconnect structure has nano- or micro-scale pore diameters, and the substrate of the metal interconnect structure is selected from damascene process chips, through-silicon via interposers, redistribution layers, substrates or printed circuit boards.

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