Composition and use thereof

Abstract

Embodiments of the present application provide a composition and a use thereof. The composition comprises a metal ion source and a polyhydroxy polymer, and the polyhydroxy polymer is formed by polymerizing monomer raw materials comprising an epoxy quaternary ammonium salt and 2,3 epoxy propanol. The composition uses the polyhydroxy polymer as a nanoscale twin crystal accelerator, and the composition can be used for preparing a metal interconnection structure, so as to prepare a nanoscale twin crystal copper material having high strength and high conductivity, thereby facilitating improvement of the interconnection reliability and the electronic product yield.

Description

Composition and application thereof

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on June 30, 2023, with application number 202310809811.5 and application name “Compositions and Their Applications”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The embodiments of the present application relate to the field of metal electroplating technology, and in particular to a composition and its application. Background Art

[0003] As packaging technology advances toward increasing interconnect density and decreasing interconnect linewidth, higher performance requirements are being placed on interconnect materials. The unique structure of nanotwinned copper materials imparts high ductility and tensile strength. Furthermore, twin boundaries are less effective at dispersing electrons, and resistance does not increase with the number of grain boundaries. Therefore, nanotwinned copper materials, with their high strength and conductivity, are ideal candidates for next-generation interconnects.

[0004] However, the primary method for preparing nanotwinned copper is currently electroplating. The key to preparing nanotwinned copper by electroplating lies in the use of additives to induce the growth of nanotwins. Traditionally, gelatin is used as an additive to induce the growth of nanotwinned copper. Gelatin is a biopolymer material primarily derived from organisms, and its source is unstable. For sophisticated and complex IC manufacturing, unstable materials are extremely difficult to control in quality. Therefore, gelatin, a traditional nanotwin promoter, is difficult to directly apply in semiconductor IC manufacturing. Furthermore, gelatin contains various hydrolyzed proteins of unknown origin, which introduce a large number of impurities into the plating solution. The inclusion of large molecular proteins can lead to a sharp decline in the quality of the coating and can also easily age the plating solution.

[0005] Summary of the Invention

[0006] In view of this, an embodiment of the present application provides a composition, which uses a polyhydroxy polymer as a nanotwin promoter. The composition can be used to electroplatingly prepare metal interconnect structures to produce nanotwin copper materials with high strength and high conductivity, thereby helping to improve interconnection reliability and electronic product yield.

[0007] In a first aspect, an embodiment of the present application provides a composition comprising a metal ion source and a polyhydroxy polymer, wherein the polyhydroxy polymer is polymerized from monomer raw materials comprising an epoxy quaternary ammonium salt and 2,3-epoxypropanol.

[0008] The above-mentioned composition provided in the embodiments of the present application is an electroplating composition, which can be used to prepare a metal layer by electroplating to form a metal interconnection structure. Among them, the polyhydroxy polymer as a nanotwin promoter can induce the formation of a high-density columnar nanotwin copper material with a highly preferred (111) crystal plane orientation, and make the nanotwin copper layer prepared by electroplating have a transition layer with an extremely low thickness, thereby greatly improving the mechanical properties of the metal copper layer and improving the interconnection reliability; and the source of the polyhydroxy polymer material is stable, and will not introduce impurities that affect the plating solution performance and the plating layer quality into the plating solution. The polyhydroxy polymer of the embodiment of the present application is obtained by a hyperbranched polymerization reaction and is a hyperbranched polyhydroxy polymer. Specifically, the polyhydroxy polymer is formed by hyperbranched polymerization of monomer raw materials including epoxy quaternary ammonium salt and 2,3-epoxypropanol. The nitrogen content in the molecular structure of the polyhydroxy polymer can be adjusted by regulating the feed ratio of epoxy quaternary ammonium salt and 2,3-epoxypropanol during the preparation process; and the nitrogen content of the polyhydroxy polymer directly affects the performance of the nanotwin structure. Therefore, the hyperbranched polyhydroxy polymer of the embodiment of the present application can be used to regulate the lamellar density of the nanotwin copper layer by regulating the nitrogen content, thereby regulating the mechanical properties of the nanotwin copper layer.

[0009] Among them, the structural formula of 2,3-epoxypropanol is: Epoxy quaternary ammonium salt is a new type of quaternary ammonium salt that introduces epoxy groups on the basis of ordinary quaternary ammonium salt. Epoxy quaternary ammonium salt contains active epoxy groups in its molecules and is easy to react with other polymer materials.

[0010] In the embodiment of the present application, the epoxy quaternary ammonium salt has the general structural formula shown in formula (1):

[0011] In formula (1), n ​​is an integer of 0≤n≤5, R1, R2 and R3 are independently selected from substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted n-propyl, substituted or unsubstituted isopropyl or derivatives thereof, and R4 is selected from H, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted n-propyl, substituted or unsubstituted isopropyl or derivatives thereof. R1, R2, R3 and R4 have a relatively small number of carbon atoms, which can reduce the steric hindrance of the epoxy quaternary ammonium salt molecules and facilitate the hyperbranching reaction.

[0012] In the present application's embodiment, the epoxy quaternary ammonium salt includes trimethyl glycidyl quaternary ammonium salt, 3,4- epoxybutyl trimethyl quaternary ammonium salt, 4,5- epoxypentyl trimethyl quaternary ammonium salt, epoxyethyl triethyl quaternary ammonium salt, 2,3- epoxypropyl triethyl quaternary ammonium salt, 1,1- two (epoxypropyl) dimethyl quaternary ammonium salt, 2- methyl glycidyl trimethyl quaternary ammonium salt, 2- ethyl glycidyl trimethyl quaternary ammonium salt, 2- propyl glycidyl trimethyl quaternary ammonium salt, 2- methyl glycidyl trimethyl quaternary ammonium salt, 2- methyl glycidyl trimethyl quaternary ammonium salt, one or more of 2- methyl glycidyl trimethyl quaternary ammonium salt.Above-mentioned epoxy quaternary ammonium salt can smoothly realize hyperbranched reaction under simpler reaction conditions with 2,3 glycidol, prepares controlled nitrogen content, the hyperbranched polyhydroxy polymer of controlled molecular weight, and above-mentioned epoxy quaternary ammonium salt raw material is easy to get.

[0013] In an embodiment of the present application, the polyhydroxy polymer is formed by polymerizing the 2,3-glycidol and the epoxy quaternary ammonium salt in a reaction ratio of less than or equal to 500:1. A suitable reaction ratio of the 2,3-glycidol to the epoxy quaternary ammonium salt can effectively control the nitrogen content in the polyhydroxy polymer, thereby better obtaining a nano-twinned copper layer with a low transition layer and a high twin density.

[0014] In the embodiment of the present application, the molecular weight of the polyhydroxy polymer is 500 g / mol-50,000 g / mol. A suitable molecular weight can make the polyhydroxy polymer disperse better in the composition and keep the viscosity of the entire composition within a suitable range.

[0015] In the embodiment of the present application, the concentration of the polyhydroxy polymer in the composition is 0.01ppm-5000ppm. Controlling the concentration of the polyhydroxy polymer within a suitable range is conducive to promoting the formation of nano-twinned copper and effectively avoiding the adverse effects that may be caused by excessive addition of the polyhydroxy polymer.

[0016] In an embodiment of the present application, the metal ion source includes any one of a copper ion source, a nickel ion source, a tin ion source, a cobalt ion source, a ruthenium ion source, and a silver ion source. The metal ion source can be a soluble metal salt, wherein the copper ion source is a soluble copper salt. In some embodiments of the present application, the copper ion source includes one or more of copper sulfate pentahydrate and copper methanesulfonate. In some embodiments of the present application, the concentration of the copper ion source in the composition is 1g / L-300g / L in terms of copper ions. Controlling the copper ion source within a suitable content range is beneficial to balancing the deposition rate and the brightness and smoothness of the resulting copper coating.

[0017] In embodiments of the present application, the composition further comprises at least one acid. In some embodiments of the present application, the at least one acid comprises one or more of sulfuric acid and methanesulfonic acid. In some embodiments of the present application, the concentration of the at least one acid in the composition is 1 g / L to 300 g / L. A suitable acid system and acid concentration are conducive to obtaining a suitable electroplating deposition rate.

[0018] In embodiments of the present application, the composition further comprises one or more of an accelerator, an inhibitor, a leveler, and an inorganic additive. The polyhydroxy polymer, in synergistic combination with one or more of these agents, can better facilitate the electroplating of metal layers on electronic substrates for various scenarios, structural dimensions, and requirements.

[0019] In the embodiment of the present application, the inorganic additive may include chloride ions, and the concentration of chloride ions in the composition is 0.1ppm-100ppm. The addition of chloride ions can improve the crystal density of the coating, making the coating finer and less rough.

[0020] In the embodiment of the present application, the leveling agent may be a copolymer of an ether and a nitrogen-containing compound. Using the copolymer of an ether and a nitrogen-containing compound as a leveling agent can effectively inhibit metal deposition in areas corresponding to high current density and improve the uniformity of the metal coating.

[0021] In some embodiments of the present application, the concentration of the leveler in the composition is 0.01-100 ppm. Controlling the leveler concentration in the composition within a suitable range facilitates achieving a moderate deposition rate, improving the uniformity and flatness of electroplating across the entire electronic substrate, thereby facilitating the production of fine circuits and enhancing the reliability of electronic products.

[0022] In embodiments of the present application, the accelerator may be one or more of sodium 3-mercapto-1-propanesulfonate (MPS), sodium polydisulfide propanesulfonate (SPS), and sodium N,N-dimethyl-dithiocarboxamide propanesulfonate (DPS). In some embodiments of the present application, the concentration of the accelerator in the composition is 0.01ppm-500ppm. The accelerator includes: the concentration of the accelerator in the electroplating composition is 0.01ppm-500ppm. The addition of the accelerator can have a depolarizing effect, accelerate metal deposition, and refine the grain size of the metal layer.

[0023] In embodiments of the present application, the inhibitor may be one or more of polyethylene glycol (PEG), polypropylene glycol (PPG), block copolymers PEO-PPO-PEO, block copolymers PPO-PEO-PPO, random copolymers of EO and PO, and propylene glycol block polyethers. In some embodiments of the present application, the concentration of the inhibitor in the composition is 1 ppm to 2000 ppm. The addition of the inhibitor can suppress the growth rate of the surface metal, which is beneficial for obtaining a thinner surface metal layer after electroplating.

[0024] In the embodiment of the present application, the nano-twinned copper layer prepared by electroplating using the composition has a (111) crystal plane orientation. The grains of the nano-twinned copper layer have a preferred (111) crystal plane orientation, which is conducive to obtaining a nano-twinned copper layer with relatively regular crystallization, improving the density of the nano-twinned copper layer, and further improving the mechanical properties of the nano-twinned copper layer.

[0025] In an embodiment of the present application, a nano-twinned copper layer electroplated using the composition has a tensile strength greater than or equal to 20% greater than that of a conventional copper layer, and a ductility greater than or equal to 30% greater than that of a conventional copper layer; wherein the conventional copper layer is prepared under the same conditions as the composition except that the polyhydroxy polymer is not added. The nano-twinned copper layer has high tensile strength and ductility, which helps reduce the risk of failure of the interconnect structure and improve interconnect reliability.

[0026] In the embodiment of the present application, the transition layer thickness of the nano-twinned copper layer prepared by electroplating the composition is less than or equal to 1 μm. A smaller transition layer thickness is conducive to obtaining a more uniform overall film layer and better overall film performance.

[0027] In the embodiment of the present application, a dimple section is present in the tensile section of the nano-twinned copper layer prepared by electroplating the composition. A dimple section refers to a section of a dimple fracture (microporous aggregation type fracture) covered with a large number of microscopic pits. These micropits (pits) are called "dimples". Dimples are the main microscopic features of plastic fracture of metals. It is a microscopic cavity produced by plastic deformation of the material within a micro-region, which is left on the section after nucleation, growth, aggregation and finally interconnection leading to fracture. The size of the dimple includes an average diameter and a depth. Generally, when the fracture conditions are the same, the larger the dimple size, the better the plasticity of the material. The presence of a dimple section in the tensile section of the nano-twinned copper layer of the embodiment of the present application indicates that the nano-twinned copper layer has good plasticity.

[0028] A second aspect of the present invention provides an application of the composition described in the first aspect in preparing a metal layer by electroplating. The composition described in the first aspect of the present invention can be used to prepare a dense nano-twinned copper layer with a highly preferred (111) crystal plane orientation by electroplating, and the thickness of the transition layer is small, thereby greatly improving the mechanical properties and interconnection quality of the metal copper layer and enhancing interconnection reliability.

[0029] In the embodiments of the present application, the metal layer comprises any one of a copper layer, a copper alloy layer, a nickel layer, a nickel alloy layer, a tin layer, a tin alloy layer, a cobalt layer, a cobalt alloy layer, a ruthenium layer, a ruthenium alloy layer, a silver layer, and a silver alloy layer. The composition described in the first aspect of the embodiments of the present application is used in the electroplating preparation of metal interconnect structures for advanced packaging to improve interconnect reliability.

[0030] In the embodiment of the present application, the electroplating of the metal layer includes electroplating the metal layer in the conductive hole on the electronic substrate to achieve metal filling. The electroplating of the metal layer can also be electroplating on electronic substrates of other structures to prepare the metal layer.

[0031] The third aspect of the embodiment of the present application provides a polyhydroxy polymer for preparing a metal layer by electroplating, wherein the polyhydroxy polymer is polymerized from monomer raw materials including epoxy quaternary ammonium salt and 2,3-epoxypropanol. The polyhydroxy polymer can be used as a nanotwin promoter to induce the generation of high-density columnar nanotwin copper materials with a high preferred (111) crystal plane orientation, and the nanotwin copper layer prepared by electroplating has a transition layer with an extremely low thickness, thereby greatly improving the mechanical properties of the metal copper layer and improving the interconnection reliability; and the polyhydroxy polymer material source is stable and will not introduce impurities that affect the performance of the plating solution and the quality of the coating into the plating solution; in addition, the polyhydroxy polymer can adjust the nitrogen content in the molecular structure of the polyhydroxy polymer by regulating the feed ratio of epoxy quaternary ammonium salt and 2,3-epoxypropanol during the preparation process; thereby regulating the sheet density of the nanotwin copper layer, thereby regulating the mechanical properties of the nanotwin copper layer to meet the needs of different scenarios.

[0032] In the embodiment of the present application, the epoxy quaternary ammonium salt has the general structural formula shown in formula (1):

[0033] In formula (1), n ​​is an integer of 0≤n≤5, R1, R2 and R3 are independently selected from substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted n-propyl, substituted or unsubstituted isopropyl or derivatives thereof, and R4 is selected from H, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted n-propyl, substituted or unsubstituted isopropyl or derivatives thereof. R1, R2, R3 and R4 have a relatively small number of carbon atoms, which can reduce the steric hindrance of the epoxy quaternary ammonium salt molecules and facilitate the hyperbranching reaction.

[0034] In the present application's embodiment, the epoxy quaternary ammonium salt includes trimethyl glycidyl quaternary ammonium salt, 3,4- epoxybutyl trimethyl quaternary ammonium salt, 4,5- epoxypentyl trimethyl quaternary ammonium salt, epoxyethyl triethyl quaternary ammonium salt, 2,3- epoxypropyl triethyl quaternary ammonium salt, 1,1- two (epoxypropyl) dimethyl quaternary ammonium salt, 2- methyl glycidyl trimethyl quaternary ammonium salt, 2- ethyl glycidyl trimethyl quaternary ammonium salt, 2- propyl glycidyl trimethyl quaternary ammonium salt, 2- methyl glycidyl trimethyl quaternary ammonium salt, 2- methyl glycidyl trimethyl quaternary ammonium salt, one or more of 2- methyl glycidyl trimethyl quaternary ammonium salt.Above-mentioned epoxy quaternary ammonium salt can smoothly realize hyperbranched reaction under simpler reaction conditions with 2,3 glycidol, prepares controlled nitrogen content, the hyperbranched polyhydroxy polymer of controlled molecular weight, and above-mentioned epoxy quaternary ammonium salt raw material is easy to get.

[0035] A fourth aspect of the present application provides a method for preparing a metal layer by electroplating, comprising the following steps:

[0036] The substrate to be electroplated is brought into contact with the composition described in the first aspect of the embodiment of the present application, and current is applied to the substrate to be electroplated for electroplating, so that a metal layer is formed on the substrate to be electroplated.

[0037] The method for preparing a metal layer by electroplating in the embodiment of the present application has a simple process and is easy to control.

[0038] In some embodiments of the present application, the substrate to be plated is provided with a via hole, and the metal layer includes an in-hole filling layer filling the via hole and a surface deposition layer deposited around the via hole.

[0039] In some embodiments of the present application, the electroplating process conditions are: electroplating temperature of 22°C-45°C, current density of 0.1ASD-15ASD, and electroplating time of 30min-300min. Under these process conditions, it is conducive to electroplating to obtain a high-quality metal layer.

[0040] The fifth aspect of the embodiment of the present application provides an electronic substrate, comprising a base layer and a metal layer arranged on the base layer, wherein the metal layer is formed by electroplating the composition described in the first aspect, or by the method for preparing a metal layer by electroplating described in the fourth aspect. The electronic substrate of the embodiment of the present application can be any substrate that requires electroplating to prepare a metal layer, and can be an amorphous substrate or a polycrystalline substrate. The structural size, shape, etc. of the electronic substrate are not particularly limited. The electronic substrate can be, for example, a silicon substrate, a compound semiconductor substrate, or an organic substrate. The aforementioned composition of the present application can be used to electroplating to obtain a dense nano-twinned copper layer with a high preferred (111) crystal plane orientation, and the thickness of the transition layer is small, thereby greatly improving the mechanical properties and interconnection quality of the metal copper layer and improving the interconnection reliability. Nano-twinned copper has high strength and high conductivity properties, and improves the interconnection reliability and performance in advanced packaging metal interconnection technologies such as ultra-fine RDL (ReDistribution Layer) and hybrid bonding.

[0041] The present embodiment further provides an electronic device, which uses the electronic substrate described in the fifth aspect of the present embodiment. The electronic device can be a chip, a transistor, or the like. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] FIG1 is a schematic diagram of copper electroplating provided in an embodiment of the present application;

[0043] FIG2 is a schematic structural diagram of an electronic substrate 100 provided in an embodiment of the present application;

[0044] FIG3 is a nuclear magnetic resonance spectrum of the polyhydroxy polymer prepared in Example 1 of the present application;

[0045] FIG4 is a cross-sectional SEM (Scanning Electron Microscope) image of the nano-twinned copper layer prepared in Example 1;

[0046] FIG5 is an XRD (X-ray diffraction) pattern of the nano-twinned copper layer prepared in Example 1;

[0047] FIG6 is an EBSD (Electron Backscattered Diffraction) pattern of the nano-twinned copper layer prepared in Example 1;

[0048] FIG7 is an SEM image of a tensile cross-section of the nano-twinned copper layer prepared in Example 1;

[0049] FIG8 is a cross-sectional SEM image of the nano-twinned copper layer prepared in Comparative Example 1;

[0050] FIG9 is an SEM image of a tensile cross-section of a conventional polycrystalline copper layer prepared in Comparative Example 2;

[0051] FIG10 is a cross-sectional SEM image of the nano-twinned copper layer of Example 2;

[0052] FIG11 is a SEM image of a cross section of the nano-twinned copper layer of Example 3;

[0053] FIG12 is a SEM image of a cross section of the nanotwinned copper layer of Example 4. DETAILED DESCRIPTION

[0054] The embodiments of the present application will be described below with reference to the accompanying drawings.

[0055] As packaging technology advances toward increasing interconnect density and continuously decreasing interconnect line width, higher requirements are placed on the performance of interconnect materials. On the one hand, the increased interconnect density leads to increased heat generation, resulting in a mismatch in the thermal expansion coefficients of copper wires and silicon, posing a risk of interconnect breakage. On the other hand, as the interconnect line width continues to decrease, the current carried by the interconnect increases, which also poses a potential risk of failure. The unique structure of nanotwinned materials gives them high ductility and tensile strength, and the twin boundaries have a weak ability to disperse electrons. Although the number of grain boundaries increases, the resistance does not increase accordingly. Therefore, nanotwinned copper materials with both high strength and high conductivity are ideal candidates for next-generation interconnect materials.

[0056] However, the main method for preparing nano-twinned copper at present is electroplating. Electroplating is a method of reducing metal ions to metal by electrochemical methods and depositing them on the surface of metal or non-metallic products to form a smooth and dense metal coating that meets the requirements. Electroplating uses a conductive substrate as the cathode, on whose surface a metal deposition reduction reaction occurs (the cathode is an electrode that receives electrons, that is, an electrode that undergoes a reduction reaction), and a soluble or insoluble anode to cause metal dissolution or oxygen evolution reaction (the anode is an electrode that can cause an oxidation reaction of the electrolyte), with the electroplating solution as the conductive circuit of the electrolyte. As shown in Figure 1, Figure 1 is a schematic diagram of copper electroplating. In the copper electroplating technology in the packaging field, the cathode plated part is the substrate to be electroplated. Through the metal deposition reaction of the cathode, the conductive metal copper is deposited into the required interconnection structure.

[0057] The key to preparing nanotwinned copper by electroplating lies in the use of additives to induce the growth of nanotwins. Traditionally, gelatin is used as an additive to induce the growth of nanotwinned copper. Gelatin is a biopolymer primarily derived from organisms, and its source is unstable. For sophisticated and complex IC manufacturing, unstable sources are extremely difficult to control. Therefore, gelatin, a traditional nanotwin promoter, is difficult to directly apply in semiconductor IC manufacturing. Furthermore, gelatin contains various hydrolyzed proteins of unknown origin, which introduce a large number of impurities into the plating solution. The inclusion of large molecular proteins can significantly reduce the quality of the coating and also make the plating solution susceptible to aging.

[0058] In order to solve the above problems, the present invention provides a polyhydroxy polymer and a composition comprising the polyhydroxy polymer. The polyhydroxy polymer provided in the present invention is polymerized from a monomer feedstock comprising a quaternary ammonium epoxy salt and 2,3-glycidol. That is, the polyhydroxy polymer simultaneously comprises a structure derived from the quaternary ammonium epoxy salt and 2,3-glycidol. The polyhydroxy polymer can be used as a nanotwin promoter, and a composition containing the polyhydroxy polymer is used as an electroplating solution for electroplating to prepare a metal layer. The specific adsorption of the polyhydroxy polymer can induce the generation of high-density columnar nanotwin copper materials with a high preferred (111) crystal plane orientation, and the nanotwin copper layer prepared by electroplating has a transition layer with an extremely low thickness, thereby greatly improving the mechanical properties and plating quality of the metal copper layer, so that the metal copper layer has both high strength and high conductivity, and improves the interconnection reliability; and the source of the polyhydroxy polymer material is stable, and no impurities that affect the plating solution performance and plating quality are introduced into the plating solution; in addition, the polyhydroxy polymer can adjust the nitrogen content in the molecular structure of the polyhydroxy polymer by regulating the feed ratio of epoxy quaternary ammonium salt and 2,3-epoxypropanol during the preparation process, and the molecular weight can also be regulated; and the transition layer thickness and the nanotwin copper layer layer density can be regulated, which is conducive to obtaining a nanotwin copper layer with a lower transition layer thickness and a higher twin density, thereby regulating the mechanical properties of the nanotwin copper layer to meet the needs of different scenarios.

[0059] In this specification, the terms "composition," "electroplating composition," "plating solution," and "electroplating solution" may be used interchangeably. The terms "copper layer," "metal layer," "metallic copper layer," "nano-twinned copper layer," "plating layer," and "copper plating layer" may be used interchangeably.

[0060] Among them, the structural formula of 2,3-epoxypropanol is: Quaternary ammonium epoxy salts are novel quaternary ammonium salts that incorporate epoxy groups into conventional quaternary ammonium salts. Because they contain active epoxy groups, these salts readily react with other polymeric materials. Compared to non-epoxy amine alcohols or ammonium alcohols, which utilize hydroxyl groups to initiate the epoxy ring-opening of 2,3-epoxypropanol, the polyhydroxy compound in this application is a hyperbranched anionic polymerization reaction between quaternary ammonium epoxy salts and 1,2-epoxypropanol. This reaction can simultaneously regulate the nitrogen content and molecular weight of the compound, thereby controlling the lamellar density of the nanotwinned copper layer.

[0061] In the embodiment of the present application, the epoxy quaternary ammonium salt has the general structural formula shown in formula (1):

[0062] In formula (1), n ​​is an integer of 0≤n≤5, R1, R2 and R3 are independently selected from substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted n-propyl, substituted or unsubstituted isopropyl or derivatives thereof, and R4 is selected from H, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted n-propyl, substituted or unsubstituted isopropyl or derivatives thereof. R1, R2, R3 and R4 have a relatively small number of carbon atoms, which can reduce the steric hindrance of the epoxy quaternary ammonium salt molecules and facilitate the hyperbranching reaction.

[0063] In formula (1), n ​​can specifically be 0, 1, 2, 3, 4 or 5. When R1, R2, R3, and R4 are substituted methyl, substituted ethyl, substituted n-propyl, or substituted isopropyl, the substituent group may be a halogen atom, an alkyl group, or the like.

[0064] In some embodiments of the present application, epoxy quaternary ammonium salt can be, for example, trimethyl glycidyl quaternary ammonium salt, 3,4- epoxybutyl trimethyl quaternary ammonium salt, 4,5- epoxypentyl trimethyl quaternary ammonium salt, epoxyethyl triethyl quaternary ammonium salt, 2,3- epoxypropyl triethyl quaternary ammonium salt, 1,1- two (epoxypropyl) dimethyl quaternary ammonium salt, 2- methyl glycidyl trimethyl quaternary ammonium salt, 2- ethyl glycidyl trimethyl quaternary ammonium salt, 2- propyl glycidyl trimethyl quaternary ammonium salt, 2- methyl glycidyl trimethyl quaternary ammonium salt, 2- methyl glycidyl trimethyl quaternary ammonium salt, one or more of 2- methyl glycidyl trimethyl quaternary ammonium salt. Above-mentioned epoxy quaternary ammonium salt can smoothly realize hyperbranched reaction with 2,3 glycidol under simpler reaction conditions, prepare a hyperbranched polyhydroxy polymer with controllable nitrogen content and controllable molecular weight, and above-mentioned epoxy quaternary ammonium salt raw material is easy to get.

[0065] In some embodiments of the present application, the polyhydroxy polymer is formed by polymerizing a monomer raw material of a quaternary ammonium epoxy salt and 2,3-epoxypropanol. In some embodiments of the present application, the polyhydroxy polymer is formed by polymerizing a monomer raw material of multiple (two or more) quaternary ammonium epoxy salts and 2,3-epoxypropanol.

[0066] In some embodiments of the present application, the polyhydroxy polymer is polymerized by 2,3-epoxypropanol and epoxy quaternary ammonium salt in a reaction feed ratio of less than or equal to 500:1. In some embodiments, the reaction feed ratio of 2,3-epoxypropanol and epoxy quaternary ammonium salt can be 20-300:1. In some embodiments, the reaction feed ratio of 2,3-epoxypropanol and epoxy quaternary ammonium salt can be 50-200:1. In some embodiments, the reaction feed ratio of 2,3-epoxypropanol and epoxy quaternary ammonium salt can be 60-150:1. In some embodiments, the reaction feed ratio of 2,3-epoxypropanol and epoxy quaternary ammonium salt can be 80-120:1. A suitable reaction feed ratio of 2,3-epoxypropanol and epoxy quaternary ammonium salt can better regulate the nitrogen content in the polyhydroxy polymer, thereby better obtaining a nano-twinned copper layer with a lower transition layer and a high twin density.

[0067] In an embodiment of the present application, the molecular weight of the polyol polymer may be 500 g / mol-50,000 g / mol. In some embodiments, the molecular weight of the polyol polymer may be, for example, 500 g / mol, 1,000 g / mol, 2,500 g / mol, 5,000 g / mol, 10,000 g / mol, 20,000 g / mol, 30,000 g / mol, 40,000 g / mol, or 50,000 g / mol. A suitable molecular weight can achieve a suitable adsorption strength on the copper surface during the coating formation process, better induce twin production, and form a coating of better quality. It can also better disperse the polyol polymer in the composition, while keeping the viscosity of the composition as a whole within a suitable range.

[0068] The present application also provides a composition comprising a metal ion source and the above-mentioned polyhydroxy polymer. The composition is an electroplating composition. The composition uses the above-mentioned polyhydroxy polymer as a nanotwin promoter, which can be used to electroplatingly prepare a metal layer to form a metal interconnection structure, and to obtain a nanotwin copper interconnection structure with high strength and high conductivity, thereby facilitating the improvement of interconnection reliability and the yield of electronic products. Among them, the polyhydroxy polymer as a nanotwin promoter can be adsorbed on the copper surface through N atoms as core adsorption centers, and the hydroxyl groups in the molecules provide appropriate polarization, thereby inducing the formation of high-density columnar nanotwin copper materials with high preferential (111) crystal plane orientation, and making the nanotwin copper layer prepared by electroplating have a transition layer with an extremely low thickness, thereby greatly improving the mechanical properties of the metal copper layer and improving the interconnection reliability; and the source of the polyhydroxy polymer material is stable, and no impurities that affect the performance of the plating solution and the quality of the plating layer will be introduced into the plating solution. The polyhydroxy polymer of the embodiment of the present application is obtained by a hyperbranched polymerization reaction and is a hyperbranched polyhydroxy polymer. Specifically, the polyhydroxy polymer is formed by hyperbranched polymerization of monomer raw materials including epoxy quaternary ammonium salt and 2,3-epoxypropanol. The nitrogen content in the molecular structure of the polyhydroxy polymer can be adjusted by regulating the feed ratio of epoxy quaternary ammonium salt and 2,3-epoxypropanol during the preparation process; and N in the polyhydroxy polymer exists as an adsorption center, and N has a strong adsorption force on the copper surface. The nitrogen content of the polyhydroxy polymer directly affects the performance of the nanotwin structure. Therefore, the hyperbranched polyhydroxy polymer of the embodiment of the present application can be used to regulate the lamellar density of the nanotwin copper layer by regulating the nitrogen content, thereby regulating the mechanical properties of the nanotwin copper layer.

[0069] In the embodiment of the present application, in the above-mentioned composition, the concentration of the polyol polymer can be 0.01ppm-5000ppm. In some embodiments of the present application, the concentration of the polyol polymer in the composition is 0.1ppm-500ppm. In some embodiments of the present application, the concentration of the polyol polymer in the composition is 0.1ppm-100ppm. Exemplarily, the concentration of the polyol polymer in the composition can be 0.01ppm, 0.1ppm, 10ppm, 50ppm, 100ppm, 200ppm, 500ppm, 1000ppm, 2000ppm, 3000ppm, 4000ppm, 5000ppm. The concentration of the polyol polymer is controlled within a suitable range, which is conducive to promoting the formation of nano-twinned copper, while effectively avoiding the adverse effects that may be caused by excessive addition of the polyol polymer, such as excessive addition of the polyol polymer may cause the coating to be mixed with too many additives so that the impurity content is high.

[0070] In an embodiment of the present application, the metal ion source includes any one of a copper ion source, a nickel ion source, a tin ion source, a cobalt ion source, a ruthenium ion source, and a silver ion source. The metal ion source can be a soluble metal salt, wherein the copper ion source is a soluble copper salt. In some embodiments of the present application, the copper ion source includes one or more of copper sulfate pentahydrate and copper methanesulfonate. For example, in some embodiments, the copper ion source includes copper sulfate pentahydrate; in some embodiments, the copper ion source includes copper methanesulfonate; in some embodiments, the copper ion source includes copper sulfate pentahydrate and copper methanesulfonate. Electroplating using the above-mentioned copper ion source acid system has high current efficiency, is environmentally friendly, and can better achieve blind hole filling through the combination of various additives.

[0071] In some embodiments of the present application, the concentration of the copper ion source in the composition is 1g / L-300g / L in terms of copper ions. In some embodiments of the present application, the concentration of the copper ion source in the composition can be 1g / L-120g / L in terms of copper ions. In some embodiments, the concentration of the copper ion source in the composition can be, for example, 1g / L, 10g / L, 20g / L, 30 / L, 40g / L, 50g / L, 60g / L, 70g / L, 80g / L, 90g / L, 100g / L, 110g / L, or 120g / L in terms of copper ions. Controlling the copper ion source within a suitable content range is beneficial for balancing deposition rate and brightness and smoothness of the resulting copper coating.

[0072] In an embodiment of the present application, the composition further comprises at least one acid. In some embodiments of the present application, the at least one acid comprises one or more of sulfuric acid and methanesulfonic acid. In some embodiments of the present application, the concentration of the at least one acid in the composition can be 1g / L-300g / L. In some embodiments, the concentration of the at least one acid in the composition can be, for example, 1g / L, 10g / L, 20g / L, 30g / L, 40g / L, 50g / L, 55g / L, 60g / L, 70g / L, 80g / L, 100g / L, 120g / L, 150g / L, 180g / L, 200g / L, 220g / L, 250g / L, 300g / L. Suitable acid systems and acid concentrations are conducive to obtaining suitable electroplating deposition rates.

[0073] In embodiments of the present application, the composition further comprises one or more of an accelerator, an inhibitor, a leveler, and an inorganic additive. The polyhydroxy polymer, in synergistic combination with one or more of these agents, can better facilitate the electroplating of metal layers on electronic substrates for various scenarios, structural dimensions, and requirements.

[0074] In an embodiment of the present application, the inorganic additive may include chloride ions, and the concentration of chloride ions in the composition may be 0.1ppm-100ppm. In some embodiments, the concentration of chloride ions in the composition may be 0.1ppm, 1ppm, 5ppm, 10ppm, 20ppm, 30ppm, 40ppm, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm, or 100ppm. The addition of chloride ions can improve the crystal density of the coating, making the coating finer and less rough.

[0075] In the embodiment of the present application, the leveling agent may be a copolymer of an ether and a nitrogen-containing compound. Using the copolymer of an ether and a nitrogen-containing compound as a leveling agent can effectively inhibit metal deposition in areas corresponding to high current density and improve the uniformity of the metal coating.

[0076] In some embodiments of the present application, the ether may be a symmetrical ether or an asymmetrical ether, may contain one ether oxygen bond or multiple ether oxygen bonds, may be an aliphatic ether or an aromatic ether; the nitrogen-containing compound may be a substituted or unsubstituted pyrrole, a substituted or unsubstituted pyrimidine, a substituted or unsubstituted nitrogen azole, a substituted or unsubstituted thiazole, a substituted or unsubstituted benzopyrrole, a substituted or unsubstituted benzimidazole, a substituted or unsubstituted benzopyridine, a substituted or unsubstituted benzopyrimidine, a substituted or unsubstituted benzotriazole, a substituted or unsubstituted benzothiazole, a substituted or unsubstituted bipyridine group, a substituted or unsubstituted triazine, etc.

[0077] In some embodiments of the present application, the concentration of the leveler in the composition may be 0.01-100ppm. In some embodiments, the concentration of the leveler is 0.1ppm-80ppm; in some embodiments, the concentration of the leveler is 1ppm-50ppm. For example, the concentration of the leveler may be 0.01ppm, 0.1ppm, 1ppm, 2ppm, 5ppm, 8ppm, 10ppm, 12ppm, 15ppm, 18ppm, 20ppm, 25ppm, 30ppm, 40ppm, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm, 100ppm. Controlling the concentration of the leveler in the composition within a suitable range is beneficial for obtaining a moderate deposition rate, improving the uniformity and flatness of the electroplating of the entire electronic substrate, thereby facilitating the production of fine circuits and improving the reliability of electronic products.

[0078] In the embodiment of the present application, the accelerator can be one or more of 3-mercapto-1-propane sulfonate sodium (MPS), polydisulfide dipropane sulfonate sodium (SPS) and N, N-dimethyl-disulfamide propane sulfonate sodium (DPS). In some embodiments of the present application, the concentration of the accelerator in the composition is 0.01ppm-500ppm. In some embodiments of the present application, the concentration of the accelerator in the composition is 0.05ppm-20ppm. In some embodiments of the present application, the concentration of the accelerator in the composition is 0.1ppm-10ppm. Exemplarily, the concentration of the accelerator in the composition is 0.01ppm, 0.05ppm, 0.1ppm, 0.2ppm, 0.5ppm, 10ppm, 20ppm, 50ppm, 100ppm, 200ppm, 300ppm, 400ppm, 500ppm. The addition of the accelerator can play a depolarizing effect to accelerate the deposition of the metal, as well as the effect of refining the grains of the metal layer.

[0079] In the embodiment of the present application, the inhibitor can be one or more of polyethylene glycol (PEG), polypropylene glycol (PPG), block copolymer PEO-PPO-PEO, block copolymer PPO-PEO-PPO, random copolymer of EO and PO, and propylene glycol block polyether. In some embodiments of the present application, the concentration of the inhibitor in the composition is 1ppm-2000ppm. In some embodiments of the present application, the concentration of the inhibitor in the composition is 10ppm-1000ppm. In some embodiments of the present application, the concentration of the inhibitor in the composition is 1ppm-10ppm. Exemplarily, the concentration of the accelerator in the composition is 1ppm, 10ppm, 20ppm, 50ppm, 100ppm, 200ppm, 300ppm, 400ppm, 500ppm, 600ppm, 700ppm, 800ppm, 900ppm, 1000ppm. The addition of the inhibitor can suppress the growth rate of the surface metal, which is conducive to obtaining a thinner surface metal layer after completing electroplating.

[0080] It is understandable that other nanotwin promoters that can promote the formation of nanotwinned copper can also be added to the composition, that is, used in combination with the polyhydroxy polymer of the embodiment of the present application.

[0081] In the embodiment of the present application, the nano-twinned copper layer prepared by electroplating using the above composition has a (111) crystal plane orientation. The grains of the nano-twinned copper layer have a preferred (111) crystal plane orientation, which is conducive to obtaining a nano-twinned copper layer with relatively regular crystallization, improving the density of the nano-twinned copper layer, and further improving the mechanical properties of the nano-twinned copper layer.

[0082] In the embodiment of the present application, the tensile strength of the nano twinned copper layer prepared by electroplating with the above composition is increased by more than or equal to 20% compared with the ordinary copper layer, and the ductility is increased by more than or equal to 30% compared with the ordinary copper layer; wherein, the ordinary copper layer is prepared under the same conditions by a plating solution without adding the polyhydroxy polymer compared with the above composition of the present application. For example, the composition of the present application includes 200 g / L copper sulfate pentahydrate, 50 g / L sulfuric acid, 60 ppm chloride ion concentration, and 100 ppm polyhydroxy polymer; the plating solution for preparing the ordinary copper layer only adds less polyhydroxy polymer than the composition of the present application, and the other components are exactly the same, and the electroplating process is also exactly the same. The nano twinned copper layer has high tensile strength and ductility, which is beneficial to reduce the risk of failure as an interconnect structure and improve the reliability of the interconnection.

[0083] In some embodiments of the present application, the tensile strength of the nano-twinned copper layer prepared by electroplating using the above composition is increased by greater than or equal to 25% compared to the ordinary copper layer, and the ductility is increased by greater than or equal to 40% compared to the ordinary copper layer. In some embodiments of the present application, the tensile strength of the nano-twinned copper layer prepared by electroplating using the above composition is increased by greater than or equal to 30% compared to the ordinary copper layer, and the ductility is increased by greater than or equal to 50% compared to the ordinary copper layer.

[0084] In an embodiment of the present application, the transition layer thickness of the nano-twinned copper layer prepared by electroplating using the above-described composition is less than or equal to 1 μm. The transition layer is a transitional state of the nano-twinned copper layer during the process of inducing twin growth by the nano-twinned accelerator and is a portion of the nano-twinned copper layer. A smaller transition layer thickness facilitates obtaining a more uniform overall electroplated film layer, thereby improving the overall performance of the electroplated film layer.

[0085] In the embodiment of the present application, a dimple section is present in the tensile section of the nano-twinned copper layer prepared by electroplating the above-mentioned composition. A dimple section refers to a section of a dimple fracture (microporous aggregation type fracture) covered with a large number of microscopic pits. These micropits (pits) are called "dimples". Dimples are the main microscopic features of plastic fracture of metals. It is a microscopic cavity produced by plastic deformation of the material within a micro-region, which is left on the section after nucleation, growth, aggregation and finally interconnection leading to fracture. The size of the dimple includes an average diameter and a depth. Generally, when the fracture conditions are the same, the larger the dimple size, the better the plasticity of the material. The presence of a dimple section in the tensile section of the nano-twinned copper layer in the embodiment of the present application indicates that the nano-twinned copper layer has good plasticity.

[0086] In some embodiments of the present application, the polyhydroxy polymer can be prepared by the following method:

[0087] Potassium tert-butoxide is added to a reaction container, and under nitrogen protection, epoxy quaternary ammonium salt, solvent, and 2,3-epoxypropanol are added to the reaction container, and the reaction is carried out at 130° C.-160° C. for 20-30 hours to obtain a polyhydroxy polymer.

[0088] The solvent may be, for example but not limited to, dimethyl sulfoxide.

[0089] The polyhydroxy polymer is prepared by a hyperbranching reaction, which can control the nitrogen content in the molecular structure of the polyhydroxy polymer by adjusting the feed ratio of the raw materials, and the molecular weight of the polyhydroxy polymer by adjusting potassium tert-butoxide. The polyhydroxy polymer is prepared by reacting 2,3-glycidol with a quaternary ammonium epoxy salt in a feed ratio of less than or equal to 500:1. In some embodiments, the feed ratio of 2,3-glycidol to the quaternary ammonium epoxy salt can be 20-300:1. In some embodiments, the feed ratio of 2,3-glycidol to the quaternary ammonium epoxy salt can be 50-200:1. In some embodiments, the feed ratio of 2,3-glycidol to the quaternary ammonium epoxy salt can be 60-150:1. In some embodiments, the feed ratio of 2,3-glycidol to the quaternary ammonium epoxy salt can be 80-120:1. The molecular weight of the polyhydroxy polymer can be 500 g / mol to 50,000 g / mol. The nitrogen content is the key to controlling the performance of the nanotwin structure. This reaction can simultaneously regulate the proportion and molecular weight of nitrogen, and the density of the nanotwin copper sheet can be controlled by adjusting the proportion of nitrogen.

[0090] The present application also provides an application of the above-mentioned composition in the electroplating preparation of a metal layer. The composition described in the embodiment of the present application can be used to prepare a dense nano-twinned copper layer with a high preferred (111) crystal plane orientation by electroplating, and the thickness of the transition layer is small, thereby greatly improving the mechanical properties and interconnection quality of the metal copper layer and improving the interconnection reliability. Nano-twinned copper has high strength and high conductivity properties, and can improve the interconnection reliability and performance in advanced packaging metal interconnection technologies such as ultra-fine RDL (ReDistribution Layer) and hybrid bonding.

[0091] In the embodiments of the present application, the electroplated metal includes the electroplated metal used in printed circuit board manufacturing processes, the electroplated metal used in integrated circuit metal interconnection processes, or the electroplated metal used in electronic packaging processes. Specifically, the electroplated metal may be the electroplated metal used in processes such as through-silicon via filling, substrate rewiring, metal bump deposition, and via filling.

[0092] In some embodiments of the present application, forming a metal layer by electroplating includes forming a metal layer by electroplating in a conductive via on an electronic substrate to achieve metal filling. The electronic substrate may be a conventional substrate, a printed circuit board, a package substrate, etc., and the conductive via may include a through hole, a blind via, and a buried via. It is understood that forming a metal layer by electroplating may also be forming a metal layer by electroplating on electronic substrates of other structures.

[0093] In the embodiments of the present application, the metal layer can be any one of a copper layer, a copper alloy layer, a nickel layer, a nickel alloy layer, a tin layer, a tin alloy layer, a cobalt layer, a cobalt alloy layer, a ruthenium layer, a ruthenium alloy layer, a silver layer, and a silver alloy layer. The composition of the embodiments of the present application can be used in the electroplating preparation of metal interconnect structures in advanced packaging to improve interconnect reliability.

[0094] The present invention also provides a method for preparing a metal layer by electroplating, comprising the following steps:

[0095] The substrate to be electroplated is brought into contact with the composition described in the embodiment of the present application, and current is applied to the substrate to be electroplated for electroplating, so that a metal layer is formed on the substrate to be electroplated.

[0096] Specifically, the substrate to be electroplated can be immersed in the electroplating composition as a cathode. The electroplating composition, i.e., the electroplating solution, serves as an electrolyte and together with a soluble or insoluble anode forms a conductive circuit, thereby achieving metal deposition on the substrate to be electroplated.

[0097] In the embodiments of the present application, there are no special restrictions on the structural size, shape, etc. of the substrate to be electroplated. In some embodiments of the present application, a via hole is provided on the substrate to be electroplated, and the metal layer includes an in-hole filling layer filling the via hole and a surface deposition layer deposited around the via hole. The via hole may be one or more of a through hole, a blind hole, and a buried hole. The via holes on the substrate to be electroplated may be exactly the same or have different diameters and depths. In the embodiments of the present application, the diameter of the via hole 10 may be 10μm-200μm, and the depth may be 20μm-200μm.

[0098] In some embodiments of the present application, the electroplating process conditions are: the electroplating temperature is 22°C-45°C, the current density is 0.1ASD-15ASD, and the electroplating time is 30min-300min. In some embodiments, the electroplating temperature is 22°C, 25°C, 30°C, 35°C, 40°C, or 45°C, the current density is 0.1ASD, 0.2ASD, 0.5ASD, 1ASD, 1.5ASD, 2ASD, 2.5ASD, 3ASD, 4ASD, 5ASD, 8ASD, 10ASD, 12ASD, or 15ASD, and the electroplating time is 30min, 60min, 90min, 120min, 150min, 180min, 200min, 250min, or 300min. Under these process conditions, it is beneficial to obtain a high-quality metal layer by electroplating.

[0099] Generally, the via hole wall is metallized before electroplating, such as chemically plating a layer of metal on the via hole wall as a metal seed layer, for example, chemically plating a layer of copper seed layer on the via hole wall.

[0100] In the embodiment of the present application, after the metal layer is formed by electroplating, the metal layer may be planarized using a process such as chemical mechanical planarization, and the surface deposited layer may be removed by planarization.

[0101] The method for preparing a metal layer by electroplating in the embodiment of the present application has a simple process and is easy to control.

[0102] 2 , an embodiment of the present application further provides an electronic substrate 100 comprising a base layer 101 and a metal layer 102 disposed on the base layer. The metal layer 102 is formed by electroplating using the composition described above in the embodiment of the present application, or is formed using the method for preparing a metal layer by electroplating described above in the embodiment of the present application.

[0103] In the embodiment of the present application, a via hole 10 is provided on the base layer 101, and the metal layer 102 includes an in-hole filling layer 1021 that fills the via hole 10 and a surface deposition layer 1022 deposited around the via hole 10. Multiple via holes 10 may be provided on the base layer 101, and the multiple via holes 10 may have different diameters and depths, or may have the same diameter and depth. In the embodiment of the present application, the diameter of the via hole 10 may be 10 μm to 200 μm, and the depth may be 20 μm to 200 μm.

[0104] In the embodiment of the present application, a chemically plated metal seed layer 103 , such as a copper seed layer, formed by metallizing the via hole 10 is further included between the base layer 101 and the metal layer 102 .

[0105] The electronic substrates of the embodiments of the present application can be any substrate requiring electroplating to form a metal layer, and can be either an amorphous substrate or a polycrystalline substrate. The electronic substrate's structure, size, shape, etc. are not particularly limited. For example, the electronic substrate can be a silicon substrate, a compound semiconductor substrate, an organic substrate, or a conductive metal substrate. The conductive metal substrate can be copper, aluminum, or any other conductive material.

[0106] The composition described above in this application can be used to prepare a dense nano-twinned copper layer with a highly preferred (111) crystal plane orientation by electroplating, and the thickness of the transition layer is small, thereby greatly improving the mechanical properties and interconnection quality of the metal copper layer and improving the interconnection reliability.

[0107] The present invention also provides an electronic device that uses the electronic substrate described above in the present invention. The electronic device can be a chip, a transistor, or the like.

[0108] The embodiments of the present application are further described below with reference to a number of embodiments.

[0109] Example 1

[0110] Potassium tert-butoxide was placed in a reaction flask, which was evacuated and filled with nitrogen. Trimethylglycidyl ammonium chloride and dimethyl sulfoxide were then added to the reaction flask. The temperature was raised to 60°C and stirred. 2,3-Epoxypropanol was then slowly injected into the reaction flask. The temperature was further raised to 150°C and the reaction was allowed to proceed for 24 hours. After the reaction was completed, the solvent was removed by distillation under reduced pressure to obtain a polyhydroxy polymer. Figure 3 shows the nuclear magnetic resonance spectrum of the polyhydroxy polymer prepared in Example 1. In Figure 3, the two peaks with chemical shifts of 3.34 and 3.64 correspond to the H on the methyl group and the H on the hydroxyl group of the product, respectively. The peak positions and area ratios are consistent with the theoretical values, demonstrating that the polyhydroxy polymer was successfully synthesized.

[0111] The polyhydroxy polymer obtained in Example 1 was prepared into an electroplating solution. The specific components of the electroplating solution were as follows: 200 g / L copper sulfate pentahydrate, 50 g / L sulfuric acid, 60 ppm chloride ion concentration, and 100 ppm polyhydroxy polymer.

[0112] A nano-twinned copper layer was electroplated on a silicon substrate of PVD Cu using a 25°C electroplating temperature and a current density of 5ASD for 40 minutes. Figure 4 is an SEM image of the nano-twinned copper layer prepared in Example 1. It can be seen from Figure 4 that the transition layer thickness of the nano-twinned copper on the polycrystalline substrate is extremely low, less than 1 μm, and the nano-twinned copper layer grows in a columnar shape from bottom to top and is arranged in an orderly manner. Figure 5 is an XRD spectrum of the nano-twinned copper layer prepared in Example 1. It can be seen from Figure 5 that the nano-twinned copper layer has an extremely high (111) crystal plane preferred orientation and basically no impurity peaks. Figure 6 is an EBSD spectrum of the nano-twinned copper layer prepared in Example 1. It can be seen from Figure 6 that the microstructure of the nano-twinned copper layer is almost entirely (111) oriented copper crystals, which confirms the results of XRD.

[0113] The nano-twinned copper layer prepared using the composition was subjected to tensile testing to measure its tensile strength and ductility. The test results are shown in Table 1. A SEM image of the tensile cross-section was taken, as shown in Figure 7. Figure 7 is an SEM image of the tensile cross-section of the nano-twinned copper layer prepared in Example 1. Figure 7 shows the presence of dimples in the tensile cross-section of the nano-twinned copper layer, which is key to improving tensile strength and ductility.

[0114] Tensile test:

[0115] A 50um nano-twinned copper layer was plated on the surface of stainless steel, and then the nano-twinned copper layer was peeled off from the stainless steel surface. After peeling, thermal annealing was performed, and then the nano-twinned copper layer was prepared into a tensile sample using a dog-bone mold, and a tensile test was performed using a universal testing machine.

[0116] Comparative Example 1

[0117] Gelatin is used as a nanotwinning promoter to prepare an electroplating solution. The specific components of the electroplating solution are as follows: 200 g / L copper sulfate pentahydrate, 50 g / L sulfuric acid, 60 ppm chloride ion concentration, and 100 ppm gelatin.

[0118] A nanotwinned copper layer was electroplated on a PVD Cu silicon substrate at a plating temperature of 25°C and a current density of 5 ASD for 40 minutes. Figure 8 shows a cross-sectional SEM image of the nanotwinned copper layer prepared in Comparative Example 1. As shown in Figure 8, the transition layer thickness is approximately 20 microns, the nanotwinned coating is not dense, and the crystallization is relatively disordered.

[0119] The nano-twinned copper layer prepared in Comparative Example 1 was subjected to a tensile test to measure its tensile strength and ductility. The tensile test operation was the same as in Example 1. The test results are shown in Table 1.

[0120] Comparative Example 2

[0121] The electroplating solution in Comparative Example 2 differs from that in Example 1 only in that it does not contain a polyhydroxy polymer. Tensile tests were performed on the conventional copper layer prepared using the electroplating solution in Comparative Example 2 to measure its tensile strength and ductility. The tensile test procedures were the same as in Example 1, and the test results are shown in Table 1. A SEM image of the tensile cross-section was taken, as shown in Figure 9. Figure 9 shows an SEM image of the tensile cross-section of the conventional polycrystalline copper layer in Comparative Example 2. As can be seen from Figure 9, the polycrystalline copper in the conventional copper layer exhibits only slip fractures, with no dimple fractures.

[0122] Table 1

[0123] The results in Table 1 indicate that the nanotwinned copper layer of Example 1 of the present application exhibits superior tensile strength and ductility to the nanotwinned copper layer of Comparative Example 1. Under the same conditions, compared to the conventional polycrystalline copper layer of Comparative Example 2, the nanotwinned copper layer of Example 1 of the present application exhibits approximately 30% greater tensile strength and approximately 50% greater ductility. The nanotwinned copper layer of the present application exhibits excellent mechanical properties and can improve interconnect reliability.

[0124] Example 2 to Example 4

[0125] Polyhydroxy polymers containing epoxy quaternary ammonium salt and 2,3-epoxypropanol at different feed ratios were prepared, and a catalyst was used to control the molecular weight of the product to be 45,000 g / mol. The specific feed ratios are shown in Table 2. Based on different feed ratios, polyhydroxy polymers with different nitrogen contents were obtained in Examples 2 to 4, and the polyhydroxy polymers in Examples 2 to 4 were respectively formulated into electroplating solutions. The difference between the electroplating solutions in Examples 2 to 4 was only that different polyhydroxy polymers were used.

[0126] A nano-twinned copper layer was electroplated on a silicon substrate of PVD Cu using the method of Example 1. Figure 10 is a cross-sectional SEM image of the nano-twinned copper layer of Example 2, Figure 11 is a cross-sectional SEM image of the nano-twinned copper layer of Example 3, and Figure 12 is a cross-sectional SEM image of the nano-twinned copper layer of Example 4. As can be seen from Figures 10 to 12, the transition layer thickness of the nano-twinned copper layers prepared in Examples 2 to 4 on the polycrystalline substrate is extremely low, and the nano-twinned copper layers grow in a columnar shape from bottom to top and are arranged in an orderly manner. The cross-sectional SEM images of the nano-twinned copper layers in the examples with different feed ratios also show that the nitrogen content has a significant effect on the twin structure. The average thickness of the transition layer of the nano-twinned copper layers plated with the electroplating solutions obtained in Examples 2 to 4 was statistically analyzed, and the results are shown in Table 2.

[0127] The nano-twinned copper layers prepared in Examples 2 to 4 were subjected to tensile tests to measure their tensile strength and ductility. The tensile test operation was the same as in Example 1. The test results are shown in Table 2.

[0128] Table 2

[0129] The experimental results in Table 2 indicate that the thickness of the transition layer is significantly affected by the feed ratio, which is attributed to the close correlation between the nitrogen content of the polyhydroxy polymer and the thickness of the transition layer. Table 2 also shows that the nano-twinned copper layers obtained in Examples 2 to 4 exhibit high tensile strength and ductility, and that the smaller the transition layer thickness, the higher the tensile strength and ductility of the nano-twinned copper layers.

[0130] It should be understood that the first, second and various numerical numbers involved in this document are only distinguished for the convenience of description and are not intended to limit the scope of this application.

[0131] In this application, "and / or" describes the relationship between related objects, indicating that three possible relationships exist. For example, "A and / or B" can mean: A exists alone, A and B exist simultaneously, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the related objects are in an "or" relationship.

[0132] In this application, "at least one" means one or more, and "more than one" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c" can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0133] In this application, "-" represents a range value, including the endpoint values ​​at both ends. For example, the molecular weight of the polyhydroxy polymer is 500g / mol-50000g / mol, which means that the molecular weight of the polyhydroxy polymer is between 500g / mol and 50000g / mol, and includes the endpoint values ​​500g / mol and 50000g / mol. It should be understood that in the various embodiments of the present application, the size of the sequence number of each process does not mean the order of execution. Some or all steps can be executed in parallel or sequentially. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

Claims

1. A composition, characterized in that The composition comprises a metal ion source and a polyhydroxy polymer, wherein the polyhydroxy polymer is polymerized from monomer raw materials comprising epoxy quaternary ammonium salt and 2,3-epoxypropanol.

2. The composition according to claim 1, characterized in that The epoxy quaternary ammonium salt has the general structural formula shown in formula (1): In formula (1), n ​​is an integer of 0≤n≤5, R1, R2 and R3 are independently selected from substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted n-propyl, substituted or unsubstituted isopropyl or derivatives thereof, and R4 is selected from H, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted n-propyl, substituted or unsubstituted isopropyl or derivatives thereof.

3. The composition according to claim 1 or 2, characterized in that The epoxy quaternary ammonium salt includes one or more of trimethyl epoxypropyl quaternary ammonium salt, 3,4-epoxybutyl trimethyl quaternary ammonium salt, 4,5-epoxypentyl trimethyl quaternary ammonium salt, epoxyethyl triethyl quaternary ammonium salt, 2,3-epoxypropyl triethyl quaternary ammonium salt, 1,1-di(epoxypropyl) dimethyl quaternary ammonium salt, 2-methyl epoxypropyl trimethyl quaternary ammonium salt, 2-ethyl epoxypropyl trimethyl quaternary ammonium salt, 2-propyl epoxypropyl trimethyl quaternary ammonium salt, 2-methyl epoxyethyl trimethyl quaternary ammonium salt, and 2-methyl epoxyethyl triethyl quaternary ammonium salt.

4. The composition according to claim 1 or 2, characterized in that The polyhydroxy polymer is polymerized by the 2,3-epoxypropanol and the epoxy quaternary ammonium salt at a reaction feed ratio of less than or equal to 500:

1.

5. The composition according to any one of claims 1 to 4, characterized in that The molecular weight of the polyhydroxy polymer is 500 g / mol-50000 g / mol.

6. The composition according to any one of claims 1 to 5, characterized in that In the composition, the concentration of the polyhydroxy polymer is 0.01 ppm-5000 ppm.

7. The composition according to any one of claims 1 to 6, characterized in that The metal ion source includes any one of a copper ion source, a nickel ion source, a tin ion source, a cobalt ion source, a ruthenium ion source, and a silver ion source.

8. The composition according to claim 7, characterized in that The copper ion source includes one or more of copper sulfate pentahydrate and copper methane sulfonate; the concentration of the copper ion source in the composition is 1 g / L-300 g / L in terms of copper ions.

9. The composition according to any one of claims 1 to 8, characterized in that The composition further comprises at least one acid; the at least one acid comprises one or more of sulfuric acid and methanesulfonic acid; and the concentration of the at least one acid in the composition is 1 g / L-300 g / L.

10. The composition according to any one of claims 1 to 9, characterized in that The composition further comprises one or more of an accelerator, an inhibitor, a leveler, and an inorganic additive.

11. The composition according to claim 10, characterized in that The inorganic additive includes chloride ions, and the concentration of the chloride ions in the composition is 0.1 ppm to 100 ppm.

12. The composition according to claim 10 or 11, characterized in that The leveler comprises a copolymer of an ether and a nitrogen-containing compound; the concentration of the leveler in the composition is 0.01-100 ppm.

13. The composition according to any one of claims 10 to 12, characterized in that The accelerator comprises one or more of sodium 3-mercapto-1-propane sulfonate, sodium polydisulfide propane sulfonate and sodium N,N-dimethyl-dithiocarboxamide propane sulfonate; the concentration of the accelerator in the composition is 0.01ppm-500ppm.

14. The composition according to any one of claims 10 to 13, characterized in that The inhibitor comprises one or more of polyethylene glycol, polypropylene glycol, block copolymer PEO-PPO-PEO, block copolymer PPO-PEO-PPO, random copolymer of EO and PO, and propylene glycol block polyether; the concentration of the inhibitor in the composition is 1ppm-2000ppm.

15. The composition according to any one of claims 1 to 14, characterized in that The nano twinned copper layer prepared by electroplating the composition has a (111) crystal plane orientation.

16. The composition according to any one of claims 1 to 15, characterized in that The tensile strength of the nano-twinned copper layer prepared by electroplating the composition is increased by greater than or equal to 20% compared with the ordinary copper layer, and the ductility is increased by greater than or equal to 30% compared with the ordinary copper layer; wherein the ordinary copper layer is prepared under the same conditions by a plating solution to which the polyhydroxy polymer is not added compared with the composition.

17. The composition according to any one of claims 1 to 16, characterized in that The transition layer thickness of the nano twinned copper layer prepared by electroplating the composition is less than or equal to 1 μm; and a dimple section exists in the tensile section of the nano twinned copper layer.

18. Use of the composition according to any one of claims 1 to 17 in preparing a metal layer by electroplating.

19. The use according to claim 18, characterized in that The metal layer includes any one of a copper layer, a copper alloy layer, a nickel layer, a nickel alloy layer, a tin layer, a tin alloy layer, a cobalt layer, a cobalt alloy layer, a ruthenium layer, a ruthenium alloy layer, a silver layer, and a silver alloy layer.

20. The use according to claim 18 or 19, characterized in that The electroplating to prepare the metal layer includes electroplating the metal layer in the conducting hole on the electronic substrate to achieve metal filling.

21. A polyhydroxy polymer for preparing a metal layer by electroplating, characterized in that: The polyhydroxy polymer is polymerized from monomer raw materials including epoxy quaternary ammonium salt and 2,3-epoxypropanol.

22. The polyhydroxy polymer according to claim 21, characterized in that The epoxy quaternary ammonium salt has the general structural formula shown in formula (1): In formula (1), n ​​is an integer of 0≤n≤5, R1, R2 and R3 are independently selected from substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted n-propyl, substituted or unsubstituted isopropyl or derivatives thereof, and R4 is selected from H, substituted or unsubstituted methyl, substituted or unsubstituted ethyl, substituted or unsubstituted n-propyl, substituted or unsubstituted isopropyl or derivatives thereof.

23. The polyhydroxy polymer according to claim 21 or 22, characterized in that The epoxy quaternary ammonium salt includes one or more of trimethyl epoxypropyl quaternary ammonium salt, 3,4-epoxybutyl trimethyl quaternary ammonium salt, 4,5-epoxypentyl trimethyl quaternary ammonium salt, epoxyethyl triethyl quaternary ammonium salt, 2,3-epoxypropyl triethyl quaternary ammonium salt, 1,1-di(epoxypropyl) dimethyl quaternary ammonium salt, 2-methyl epoxypropyl trimethyl quaternary ammonium salt, 2-ethyl epoxypropyl trimethyl quaternary ammonium salt, 2-propyl epoxypropyl trimethyl quaternary ammonium salt, 2-methyl epoxyethyl trimethyl quaternary ammonium salt, and 2-methyl epoxyethyl triethyl quaternary ammonium salt.

24. A method for preparing a metal layer by electroplating, characterized in that: The following steps are involved: The substrate to be electroplated is contacted with the composition according to any one of claims 1 to 17, and current is applied to the substrate to be electroplated for electroplating, so that a metal layer is formed on the substrate to be electroplated.

25. The method of claim 24, wherein: The substrate to be electroplated is provided with a via hole, and the metal layer includes an in-hole filling layer filling the via hole and a surface deposition layer deposited around the via hole.

26. The method according to claim 24 or 25, characterized in that The electroplating process conditions are: electroplating temperature is 22° C.-45° C., current density is 0.1ASD-15ASD, and electroplating time is 30min-300min.

27. An electronic substrate, characterized in that: It comprises a base layer and a metal layer arranged on the base layer, wherein the metal layer is formed by electroplating the composition according to any one of claims 1 to 17, or is formed by the method for preparing a metal layer by electroplating according to any one of claims 24 to 26.

28. An electronic device, characterized in that: The electronic device uses the electronic substrate according to claim 27.

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