Polymer, leveling agent and method for preparing the same, electroplating solution, and electroplating method

Abstract

This application discloses polymers, leveling agents and methods for preparing them, electroplating solutions and electroplating methods, relating to the field of electroplating technology. [Solution] The polymer comprises multiple repeating units, each repeating unit comprising a binary epoxy compound residue and a nitrogen-containing group. The binary epoxy compound residue is a residue formed after the epoxy bond of the binary epoxy compound is ring-opened. The nitrogen-containing group comprises an alkyl group and a dimethylamine group and a nitrogen-containing heterocyclic group attached to the two ends of the alkyl group, respectively, with the dimethylamine group further attached to the binary epoxy compound residue via a single bond. The polymer is useful for obtaining highly coplanar plating at high current densities and is particularly suitable for use as a leveling agent in electroplating solutions.

Description

Technical Field

[0001] This disclosure claims the priority of Chinese Patent Application No. 202111168841.X, titled "POLYMER, LEVELING AGENT AND PREPARATION METHOD THEREOF, ELECTROPLATING SOLUTION, AND ELECTROPLATING METHOD", filed on September 30, 2021, the entire content of which is incorporated herein by reference.

[0002] This disclosure relates to the field of electroplating technology, and in particular, to polymers, leveling agents, and their preparation methods, electroplating solutions, and electroplating methods.

Background Art

[0003] In the manufacturing process of integrated circuits, an electroplating process is usually used to form electrical interconnecting lines. For example, in an electroplating solution, electroplating is performed by using copper as the anode and a silicon wafer as the cathode, so that copper is deposited on the silicon wafer to form copper pillars. The copper pillars are electrical interconnecting lines. In order to avoid poor electrical connection, the copper pillars on the silicon wafer need to have high coplanarity.

[0004] In the prior art, a leveling agent is added to the electroplating solution to improve the coplanarity of the copper pillars. For example, the chemical structural formula of the leveling agent is shown below:

Chem.

[0005] However, leveling agents are not suitable for use at high current densities. When electroplating is performed using an electroplating solution containing a leveling agent, an increase in current density indicates a decrease in the coplanarity of the copper pillars. [Overview of the Initiative]

[0006] With this in mind, this disclosure provides a polymer, a leveling agent and a method for preparing the same, an electroplating solution, and an electroplating method to solve the above technical problems.

[0007] Specifically, this includes several technical solutions, such as the following: [Means for solving the problem]

[0008] In one embodiment, a polymer is provided. The polymer comprises a plurality of repeating units, each repeating unit comprising a binary epoxy compound residue and a nitrogen-containing group.

[0009] A binary epoxy compound residue is a residue that is formed after the epoxy bond in a binary epoxy compound is opened.

[0010] The nitrogen-containing group comprises an alkyl group and two dimethylamine groups and a nitrogen-containing heterocyclic group attached to the two ends of the alkyl group, respectively, with the dimethylamine group further attached to a binary epoxy compound residue via a single bond.

[0011] In the polymers provided in this embodiment of the Disclosure, binary epoxy compound residues and nitrogen-containing groups are combined to form repeating units. Both the dimethylamine group and the nitrogen-containing heterocyclic group of the nitrogen-containing group contain an N atom. Therefore, both the dimethylamine group and the nitrogen-containing heterocyclic group are strongly positive functional groups and have a strong positiveity. When the polymer is used in an electroplating process, the N atoms in the nitrogen-containing groups of the polymer can be characteristically adsorbed in the high current density region of the cathode to be plated in order to compete with anodic ions. In this way, the polymer suppresses metal deposition in the high current density region through steric hindrance and slows down the electroplating rate in the high current density region. Furthermore, when nitrogen-containing groups are used, they are used in combination with binary epoxy compound residues. In regions of higher convection intensity, the polymer has stronger adsorption to the cathode to be plated, and in regions of lower convection intensity, the polymer has weaker absorption to the cathode to be plated. Furthermore, by adaptively adjusting the adsorption of the polymer to the plated cathode based on the current density value, strong suppression of metal deposition can be provided in the high current density region, and weak suppression of metal deposition can be provided in the low current density region.

[0012] The polymers provided in this embodiment of the present disclosure are particularly applicable to facilitate obtaining highly uniform plating and to obtaining highly coplanar plating at high current densities. This is particularly applicable to use as a leveling agent for electroplating solutions, as it has positive implications for improving the coplanarity of the plating while increasing the plating rate at high current densities.

[0013] In some possible embodiments, the number of carbon atoms in the alkyl group is in the range of 1 to 5, for example, 1, 2, 3, 4, and 5. Having the number of carbon atoms in the alkyl group within this range allows the polymer to have an appropriate polymer molecular weight, and the polymer can obtain a better adsorption capacity to the plated cathode.

[0014] In some possible embodiments, the nitrogen-containing heterocyclic group is a morpholine group or a pyrrole group. Since both the morpholine group and the pyrrole group are strongly positive groups, they can promote the adsorption of the polymer in the high current density region.

[0015] In some possible embodiments, the chemical structural formula of the nitrogen-containing group includes the following:

Chemical formula

Chemical formula

[0016] In some possible embodiments, the binary epoxy compound residue includes a non-epoxy connecting group and two epoxy residues respectively connected to two ends of the non-epoxy connecting group.

[0017] The epoxy residue is a residue formed after the epoxy bond is ring-opened, and the epoxy residue is connected to a dimethylamine group.

[0018] In some possible embodiments, the chemical structural formula of the binary epoxy compound residue is one of the following chemical structural formulas:

Chemical formula

Chemical formula

[0019] In some possible embodiments, the amount of the repeating unit is in the range of 3 to 100, so that the polymer has an appropriate polymer molecular weight, and the polymer can obtain better adsorption ability to the electroplated cathode part.

[0020] In some possible embodiments, the chemical structural formula of the polymer is shown as follows: [Chemical formula] Wherein 0 ≦ a ≦ 8, 1 ≦ b ≦ 5, 3 ≦ n ≦ 100, and a, b, and n are all integers, R is [Chemical formula] or [Chemical formula] is.

[0021] The polymer having the above chemical structural formula is particularly useful for obtaining a very uniform plating and is applicable for obtaining a high coplanarity plating at a high current density. That is, when the polymer having the above chemical structural formula is used in an electroplating solution, the incompatibility between the production efficiency of electroplating and the coplanarity of the plating can be effectively eliminated. On the premise that the coplanarity of the plating is not lost, the electroplating speed can be significantly improved.

[0022] In another aspect, a method for preparing a polymer is further provided, wherein the polymer contains a plurality of repeating units. The repeating unit includes a binary epoxy compound residue and a nitrogen-containing group. The nitrogen-containing group includes an alkyl group, a dimethylamine group and a nitrogen-containing heterocyclic group respectively connected to two ends of the alkyl group, and the dimethylamine group is further connected to the binary epoxy compound residue through a single bond.

[0023] The method for preparing a polymer includes performing a polymerization reaction between a binary epoxy compound and a nitrogen-containing compound in a solvent to obtain the polymer.

[0024] As the binary epoxy compound residue, a residue formed after the epoxy bond of the binary epoxy compound is ring-opened is used.

[0025] The nitrogen-containing compound comprises an alkyl group and amine groups and nitrogen-containing heterocyclic groups attached to the two ends of the alkyl group, respectively. The nitrogen-containing group used is a residue formed after the amine group of the nitrogen-containing compound has participated in the polymerization reaction.

[0026] The two epoxy groups at the two terminal ends of the binary epoxy compound and the amine group of the nitrogen-containing compound participate in the polymerization reaction, and the epoxy group of the binary epoxy compound can polymerize with the active hydrogen of the amine group of the nitrogen-containing compound. During the reaction, the epoxy group is ring-opened to produce a hydroxyl group and a methylene group, and the amine group forms a dimethylamine group. The dimethylamine group is used as a nucleophile and is connected to the methylene group. That is, the epoxy group of the binary epoxy compound forms the hydroxyl group and methylene group of the binary epoxy compound residue after polymerization, and the amino group of the nitrogen-containing compound forms the dimethylamine group of the nitrogen-containing group after polymerization. The dimethylamine group and the methylene group are connected by a single bond, and further connection between the nitrogen-containing group and the binary epoxy compound residue is achieved, resulting in the polymer shown in this embodiment of the present disclosure.

[0027] In some possible embodiments, the number of carbon atoms in the alkyl group is in the range of 1 to 5. Having the number of carbon atoms in the alkyl group within this range allows the polymer to have an appropriate polymer molecular weight, and the polymer can obtain better adsorption capacity to the plated cathode.

[0028] In some possible embodiments, the nitrogen-containing heterocyclic group is a morpholine group or a pyrrole group.

[0029] In some possible embodiments, the chemical structural formula of the nitrogen-containing compound includes the following: [ka] or [ka] During the ceremony b is an integer such that 1 ≤ b ≤ 5.

[0030] In some possible embodiments, the binary epoxy compound comprises a non-epoxy connecting group and two epoxy groups, each attached to the two ends of the non-epoxy connecting group.

[0031] In some possible embodiments, the chemical structure of the binary epoxy compound is one of the following chemical structures: [ka] [ka] or [ka] During the ceremony a1, a2, a3, and a4 are all integers, each in the range of 0 to 8.

[0032] In some possible embodiments, the reaction temperature of the polymerization reaction is in the range of 60°C to 75°C. Within this reaction temperature range, the polymerization reaction can be carried out rapidly and thoroughly, resulting in a fast reaction rate. Furthermore, the reaction temperature can be stably maintained by a water bath or an oil bath.

[0033] In some possible embodiments, the solvent comprises at least one of ethanol, methanol, and water.

[0034] In yet another embodiment, the use of any one of the aforementioned polymers in the preparation of a leveling agent is provided.

[0035] Any one of the aforementioned polymers is any one of the polymers in the aforementioned embodiments of the polymers and the embodiments of the polymer preparation method in this disclosure.

[0036] The polymers provided in this embodiment of the Disclosure may be used to prepare leveling agents. In some cases, the polymers may be used directly as leveling agents, and the leveling agents obtained by preparation are particularly useful for obtaining very uniform plating. Furthermore, the prepared leveling agents are applicable to obtaining highly coplanar plating at high current densities. In other words, leveling agents prepared based on the polymers provided in this embodiment of the Disclosure can effectively resolve the incompatibility between electroplating production efficiency and the coplanarity of the plating. Assuming that the coplanarity of the plating (e.g., the coplanarity of copper pillars) is not lost, the electroplating rate can be significantly improved. For example, the electroplating rate can be improved to at least more than 2 μm / min and even more than 4 μm / min.

[0037] In yet another embodiment, a leveling agent is provided, which comprises one of the aforementioned polymers.

[0038] Any one of the aforementioned polymers is any one of the polymers in the aforementioned embodiments of the polymers and the embodiments of the polymer preparation method in this disclosure.

[0039] In some possible embodiments, the chemical structure of the polymer is shown below: [ka] During the ceremony 2≦a≦4, 2≦b≦3, 5≦n≦40, R is [ka] or [ka] That is the case.

[0040] In yet another embodiment, a method for preparing a leveling agent is provided. The method for preparing the leveling agent is the same as any one of the polymer preparation methods described above in embodiments of the present disclosure. In other words, the leveling agent expected in this embodiment of the present disclosure can be obtained by using the same method as any one of the polymer preparation methods in embodiments of the present disclosure.

[0041] According to yet another embodiment of the embodiments of the present disclosure, an electroplating solution is provided, the electroplating solution comprising any one of the leveling agents described above.

[0042] Any one of the leveling agents described above in the embodiments of this disclosure can be used in an electroplating solution to obtain a highly uniform plating. Furthermore, high coplanarity plating can be obtained at high current densities. The electroplating solution provided in this embodiment of the disclosure effectively resolves the incompatibility between electroplating production efficiency and plating coplanarity. Assuming that the coplanarity of the plating (e.g., the coplanarity of copper pillars) is not lost, the electroplating rate can be significantly improved. Using the electroplating solution provided in this embodiment of the disclosure to solve the aforementioned technical problems is easier, more convenient, more reliable, and further facilitates the maintenance of the electroplating solution compared to improving the equipment or replacing the electroplating solution system.

[0043] In some possible embodiments, the electroplating solution further comprises a metal salt, an acidic solution, a water-soluble chloride, an accelerator, and an inhibitor. The concentration of metal salts in the electroplating solution ranges from 5 g / L to 300 g / L. The concentration of the acidic solution for electroplating ranges from 10 g / L to 300 g / L. The chloride ion concentration of the water-soluble chloride in the electroplating solution ranges from 1 ppm to 100 ppm. The concentration of the leveling agent in the electroplating solution ranges from 0.01 ppm to 1000 ppm. The concentration of the accelerator in the electroplating solution ranges from 0.01 ppm to 100 ppm. The concentration of the inhibitor in the electroplating solution ranges from 1 ppm to 2000 ppm.

[0044] In some possible embodiments, the metal salt comprises at least one of copper sulfate, copper cyanide, and copper pyrophosphate. The acidic solution contains at least one of sulfuric acid, hydrochloric acid, and an organic acid. The water-soluble chlorides include at least one of hydrochloric acid, sodium chloride, potassium chloride, and ammonium chloride.

[0045] In some possible embodiments, the accelerator is at least one of sodium polydisulfide dipropanesulfonate and sodium 3-mercapto-1-propanesulfonate. The above types of accelerators promote a high-density distribution of the plating, improve the uniform plating ability of the electroplating solution, and enable the plating to be smooth and reflective.

[0046] The inhibitor comprises at least one of polyethylene glycol, polypropylene glycol, PEO-PPO-PEO block copolymer, and PPO-PEO-PPO block copolymer. The aforementioned types of inhibitors readily adsorb to the active sites of grain growth. This increases the resistance to electrochemical reactions and improves electrochemical polarization, resulting in grain refinement and suppression of plating growth on the substrate surface.

[0047] According to yet another embodiment of the present disclosure, a method for electroplating a part to be plated is provided. The method includes using one of the electroplating solutions described above.

[0048] The part to be plated is the cathode part to be plated, and the material of the part to be plated includes, but is not limited to, resin, ceramic, metal, silicon die, etc.

[0049] By performing electroplating using the electroplating solution provided in this embodiment of the disclosure, highly uniform plating can be obtained. In particular, highly uniform plating can still be obtained even at high current densities and fast plating speeds. Furthermore, high electroplating efficiency is ensured.

[0050] In some possible embodiments, the method includes performing electroplating at a current density of 5ASD or higher.

[0051] In some possible embodiments, the method includes performing electroplating at a current density of 15ASD or higher.

[0052] In some examples, a method for electroplating a part to be plated provided in this embodiment of the present disclosure includes performing electroplating at a plating rate of 2 μm / min or more.

[0053] The electroplating method provided in this embodiment of the present disclosure is applicable when used at high current densities to obtain highly coplanar plating.

[0054] In some examples, in this embodiment of the present disclosure, a silicon wafer is used as the cathode to be plated, copper ions are used as the metal to be plated, and the electroplating operation is performed with the aforementioned electroplating solution, as a result, highly coplanar copper pillars can be formed on the silicon wafer. Furthermore, the current density during electroplating is greater than 5ASD, and moreover, the current density is 15ASD or higher. The plating speed exceeds 2 μm / min, and moreover, the plating speed exceeds 4 μm / min. [Brief explanation of the drawing]

[0055] [Figure 1] This is a laser confocal microscope image of a copper pillar according to Test Case 1 of this disclosure. [Figure 2] This is a laser confocal microscope image of a copper pillar according to Test Case 2 of this disclosure. [Figure 3]This is a laser confocal microscope image of a copper pillar according to Test Case 3 of this disclosure. [Figure 4] This is a laser confocal microscope image of a copper pillar according to Comparative Example 1 of this disclosure. [Figure 5] This is a laser confocal microscope image of a copper pillar according to Comparative Example 2 of this disclosure. [Modes for carrying out the invention]

[0056] To clarify the technical solutions and advantages of this disclosure, embodiments of this disclosure will be described in further detail hereafter with reference to the attached drawings.

[0057] As an important component of semiconductor chips, metal interconnects can interconnect the components of an integrated circuit to form the necessary circuits. A typical metal interconnect widely used in integrated circuits is the copper pillar (Cu pillar). In integrated circuits, copper pillars are used to form connections between the chip and the substrate, and they offer excellent electrical performance, thermal performance, and reliability. Copper pillars are obtained by preparation based on an electroplating process. The electroplating process involves using copper as the anode, a silicon wafer as the cathode, and performing electroplating in an electroplating solution, resulting in the deposition of copper onto the silicon wafer to form a copper pillar.

[0058] To avoid electrical connection failures, high requirements are placed on the flatness, or coplanarity, of copper pillars. Generally, the non-coplanarity ratio, which represents the coplanarity of copper pillars, is required to be less than 10%, and as a result, copper pillars have high coplanarity.

[0059] The non-coplanarity ratio represents the ratio of the height of defects such as convex or concave parts on the upper surface of a single copper pillar to the height of the shoulder of the copper pillar, and also represents the difference in height of copper pillars in the cathode portion of the same plated material (i.e., the coplanarity of the copper pillar array). The difference is represented as follows: for each die wafer, the difference between the maximum value of the copper pillars and the minimum value of the copper pillars is divided by twice the average height of the copper pillars.

[0060] Conventional techniques improve the coplanarity of copper pillars by adding a leveling agent to the electroplating solution. For example, the chemical structure of a leveling agent is shown below: [ka] During the ceremony X is a hydrogen atom, alkyl group, monool, diol, triol, or polyol group; Y is a hydrogen atom, alkyl group, monool, diol, triol, or polyol group; and R is a nitrogen-containing atomic group.

[0061] Current density directly affects the plating rate of copper pillars, and further affects the production efficiency of copper pillars, with higher current densities indicating higher-order plating rates. To achieve high copper pillar production efficiency, the current density is expected to exceed 5 ASD (amperes / square decimeter) during electroplating. However, leveling agents provided in the prior art are not suitable for use at high current densities. When electroplating is performed using an electroplating solution containing a leveling agent, an increase in current density indicates a decrease in the coplanarity of the copper pillars. It is therefore clear that there is a critical need to provide a leveling agent suitable for use at high current densities.

[0062] According to another embodiment of the embodiments of the present disclosure, embodiments of the present disclosure provide a polymer comprising a plurality of repeating units, each repeating unit comprising a binary epoxy compound residue and a nitrogen-containing group.

[0063] A binary epoxy compound residue is a residue that is formed after the epoxy bond in a binary epoxy compound is opened.

[0064] The nitrogen-containing group comprises an alkyl group and two dimethylamine groups and a nitrogen-containing heterocyclic group attached to the two ends of the alkyl group, respectively, with the dimethylamine group further attached to a binary epoxy compound residue via a single bond.

[0065] In electroplating processes, the cathode is typically the irregular area to be plated. For example, the cathode is a graph with different interconnection structures. Based on the initial current density distribution in the electroplating process, the current density is higher in the short-range region where the cathode is located and the geometric distance from the anode is smaller (i.e., closer), and lower in the long-range region where the cathode is located and the geometric distance from the anode is larger (i.e., farther). The difference in current density due to the geometric structure of the cathode results in non-uniform plating on the cathode area to be plated. According to the rules of current density distribution, the higher the current density, the more severe the non-uniformity of the plating becomes. Microelectronics manufacturing processes impose very high and almost strict requirements on the metal interconnection structure, i.e., plating uniformity. Therefore, when electroplating processes are used in microelectronics manufacturing, additives need to be added to the electroplating solution to ensure uniformity of the plating on the cathode area to be plated, by characteristically accelerating and suppressing the deposition rate of plating at different locations and achieving uniform plating.

[0066] In the polymers provided in this embodiment of the Disclosure, binary epoxy compound residues and nitrogen-containing groups are combined to form repeating units. Both the dimethylamine group and the nitrogen-containing heterocyclic group of the nitrogen-containing group contain an N atom. Therefore, both the dimethylamine group and the nitrogen-containing heterocyclic group are strongly positive functional groups and possess strong positive charge. When the polymer is used in an electroplating process, the N atoms in the nitrogen-containing groups of the polymer can be characteristically adsorbed in the high current density region of the cathode to be plated in order to compete with anodic ions. In this way, the polymer suppresses metal deposition (e.g., copper deposition) in the high current density region through steric hindrance and slows down the electroplating rate in the high current density region. Furthermore, when nitrogen-containing groups are used, they are used in combination with binary epoxy compound residues, and the polymer has convection-dependent and current-intensity-dependent properties (convection means that the electroplating solution is flowing, and the greater the flow velocity of the electroplating solution, the greater the convection intensity). Thus, in regions of higher convection intensity, the polymer exhibits stronger adsorption to the plated cathode, while in regions of lower convection intensity, the polymer exhibits weaker absorption to the plated cathode. Furthermore, by adaptively adjusting the adsorption of the polymer to the plated cathode based on the current density value, strong suppression of metal deposition can be provided in regions of high current density, and weak suppression of metal deposition can be provided in regions of low current density.

[0067] The polymers provided in this embodiment of the present disclosure are found to facilitate obtaining very uniform plating and are particularly applicable to obtaining highly coplanar plating at high current densities. This is particularly applicable to use as a leveling agent for electroplating solutions, as it has positive implications for improving the coplanarity of the plating while increasing the plating rate at high current densities.

[0068] In some possible embodiments, the amount of carbon atoms in the alkyl group in the nitrogen-containing group is in the range of 1 to 5, for example, 1, 2, 3, 4, and 5. Having the amount of carbon atoms in the alkyl group within this range allows the polymer to have an appropriate polymer molecular weight, and the polymer can obtain a better adsorption capacity to the plated cathode.

[0069] In some possible embodiments, the nitrogen-containing heterocyclic group is either a morpholine group or a pyrrole group. Since both morpholine and pyrrole groups are strongly positive groups, they can facilitate the adsorption of the polymer in the high current density region.

[0070] Based on the above description, in this embodiment of the present disclosure, the chemical structural formula of the nitrogen-containing group includes one of the following chemical structural formulas: [ka] or [ka] , In the formula, b is an integer, and 1 ≤ b ≤ 5.

[0071] The binary epoxy compound residue is a residue derived from a binary epoxy compound, where the two epoxy bonds of the binary epoxy compound participate in the polymerization reaction, followed by ring-opening to form the aforementioned binary epoxy compound residue.

[0072] In some possible embodiments, the binary epoxy compound residue comprises a non-epoxy connecting group and two epoxy residues, each attached to the two ends of the non-epoxy connecting group. The epoxy residues are formed after the epoxy bond is ring-opened, and the epoxy residues are attached to the dimethylamine group.

[0073] A non-epoxy conjugate group is a group that does not contain an epoxy group. If we define a non-epoxy conjugate group as M, the chemical structure of the binary epoxy compound residue is as follows: [ka]

[0074] The chemical structure of the polymer formed by combining a binary epoxy compound residue and a nitrogen-containing group is shown below: [ka]

[0075] In some possible embodiments, the chemical structure of the binary epoxy compound residue is one of the following chemical structures. [ka] or [ka]

[0076] In these expressions, a1, a2, a3, and a4 are all integers, each in the range of 0 to 8. For example, each could be 0, 1, 2, 3, 4, 5, 6, 7, or 8.

[0077] In some possible embodiments, the amount of repeating units of the polymer is in the range of 3 to 100, for example, integers in the range of 3 to 90, integers in the range of 3 to 80, integers in the range of 3 to 70, integers in the range of 3 to 60, integers in the range of 3 to 50, integers in the range of 3 to 40, integers in the range of 3 to 30, or integers in the range of 3 to 20. This allows the polymer to have an appropriate molecular weight and to obtain better absorption performance to the plated cathode.

[0078] In some possible embodiments, embodiments of the present disclosure provide such polymers. The chemical structural formulas of the polymers are shown below: [ka] During the ceremony, 0 ≤ a ≤ 8, 1 ≤ b ≤ 5, 3 ≤ n ≤ 100, and a, b, and n are all integers. R is [ka] or [ka] That is the case.

[0079] For example, a can be 0, 1, 2, 3, 4, 5, 6, 7, or 8; b can be 1, 2, 3, 4, or 5; and n can be an integer in the range of 3 to 100, such as an integer in the range of 3 to 90, an integer in the range of 3 to 80, an integer in the range of 3 to 70, an integer in the range of 3 to 60, an integer in the range of 3 to 50, an integer in the range of 3 to 40, an integer in the range of 3 to 30, or an integer in the range of 3 to 20.

[0080] The polymer having the above chemical structure provided in this embodiment of the present disclosure is particularly useful for obtaining highly uniform plating and is applicable to obtaining highly coplanar plating at high current densities. That is, when the polymer having the above chemical structure is used in an electroplating solution, the incompatibility between the production efficiency of electroplating and the coplanarity of the plating can be effectively resolved. The electroplating rate can be significantly increased while ensuring the coplanarity of the plating (e.g., the coplanarity of copper pillars). For example, the electroplating rate can be increased to more than 2 μm / min, and even more than 4 μm / min. Compared to improving the equipment or replacing the electroplating solution system, using the polymer provided in this embodiment of the present disclosure to solve the aforementioned technical problems is easier, more convenient, more reliable, and further facilitates the maintenance of the electroplating solution.

[0081] In some examples, a is 2, 3, or 4; b is 2 or 3; and n is an integer ranging from 5 to 40. This allows the polymer to have an appropriate molecular weight and N atomic density, resulting in better adsorption performance to the plated cathode.

[0082] For example, if a is 2, b is 2, and R is [ka] In that case, the chemical structural formula corresponding to the polymer is shown below. [ka]

[0083] For example, if a is 2, b is 3, and R is [ka] In that case, the chemical structural formula corresponding to the polymer is shown below. [ka]

[0084] For example, if a is 2, b is 3, and R is [ka] If so, the corresponding chemical structure of the polymer is shown as follows: [ka] .

[0085] For example, if a is 4, b is 3, and R is [ka] In that case, the chemical structural formula corresponding to the polymer is shown below. [ka]

[0086] According to another embodiment of the present disclosure, a method for preparing a polymer is further provided in which the polymer comprises a plurality of repeating units. The repeating units comprise a binary epoxy compound residue and a nitrogen-containing group. The nitrogen-containing group comprises an alkyl group and a dimethylamine group and a nitrogen-containing heterocyclic group attached to the two ends of the alkyl group, respectively, the dimethylamine group being further attached to the binary epoxy compound residue via a single bond.

[0087] The polymer preparation method includes obtaining a polymer by carrying out a polymerization reaction between a binary epoxy compound and a nitrogen-containing compound in a solvent.

[0088] For the binary epoxy compound residues in the polymer, residues formed after the ring-opening of the epoxy bond in the binary epoxy compound are used.

[0089] The nitrogen-containing compound comprises an alkyl group and amine groups and nitrogen-containing heterocyclic groups attached to the two ends of the alkyl group, respectively. The nitrogen-containing group used is a residue formed after the amine group of the nitrogen-containing compound has participated in the polymerization reaction.

[0090] According to the polymer preparation method provided in this embodiment of the present disclosure, the polymerization reaction is carried out in a solvent with a binary epoxy compound and a nitrogen-containing compound. The two epoxy groups at the two ends of the binary epoxy compound and the amine group of the nitrogen-containing compound participate in the polymerization reaction, and the epoxy group of the binary epoxy compound can polymerize with the active hydrogen of the amine group of the nitrogen-containing compound. During the reaction, the epoxy group is ring-opened to produce a hydroxyl group and a methylene group, and the amine group forms a dimethylamine group. The dimethylamine group is used as a nucleophile and is linked to the methylene group. That is, the epoxy group of the binary epoxy compound forms the hydroxyl group and methylene group of the binary epoxy compound residue after polymerization, and the amino group of the nitrogen-containing compound forms the dimethylamine group of the nitrogen-containing group after polymerization. The dimethylamine group and the methylene group are linked by a single bond, and further linkage between the nitrogen-containing group and the binary epoxy compound residue is achieved to obtain the polymer shown in this embodiment of the present disclosure.

[0091] The repeating units of the polymer obtained by the polymer preparation method described above contain binary epoxy compound residues and nitrogen-containing groups. The nitrogen-containing groups include an alkyl group and dimethylamine groups and nitrogen-containing heterocyclic groups attached to the two ends of the alkyl group, respectively, with the dimethylamine groups further attached to the binary epoxy compound residues via single bonds.

[0092] In nitrogen-containing compounds, alkyl groups and nitrogen-containing heterocyclic groups do not participate in the polymerization reaction; therefore, the alkyl groups and nitrogen-containing heterocyclic groups of nitrogen-containing compounds are the same as the alkyl groups and nitrogen-containing heterocyclic groups of nitrogen-containing groups in the polymer.

[0093] The molecular weight of the polymer (i.e., the number of repeating units) can be controlled by at least one of the following parameters: the mass of the binary epoxy compound and the nitrogen-containing compound, the reaction time, and the reaction temperature. For example, if the reaction time is 24 hours or less, longer reaction times will result in a greater number of repeating units, provided that the amounts of the binary epoxy compound and the nitrogen-containing compound are sufficient. When the reaction time exceeds 24 hours, the number of repeating units can be further controlled by using other factors.

[0094] In some possible embodiments, the amount of carbon atoms in the alkyl group in the nitrogen-containing group is in the range of 1 to 5, for example, 1, 2, 3, 4, and 5. Having the amount of carbon atoms in the alkyl group within this range allows the polymer to have an appropriate polymer molecular weight, and the polymer can obtain a better adsorption capacity to the plated cathode.

[0095] In some possible embodiments, the nitrogen-containing heterocyclic group is either a morpholine group or a pyrrole group. Since both morpholine and pyrrole groups are strongly positive groups, they can facilitate the adsorption of the polymer in the high current density region.

[0096] In some possible embodiments, the chemical structural formula of the nitrogen-containing compound in this embodiment of the present disclosure includes: [ka] or [ka] And in the formula b is an integer such that 1 ≤ b ≤ 5.

[0097] For example, in the case of a nitrogen-containing compound having a morpholine group, when b is 2, the nitrogen-containing compound is N-(2-aminoethyl)morpholine; when b is 3, the nitrogen-containing compound is N-(3-aminopropyl)morpholine.

[0098] If b is 2, the nitrogen-containing compound having a pyrrole group is N-(2-aminoethyl)pyrrolidine; if b is 3, the nitrogen-containing compound is N-(3-aminopropyl)pyrrolidine.

[0099] In some possible embodiments, the binary epoxy compound includes a non-epoxy connecting group and two epoxy groups attached to the two ends of the non-epoxy connecting group, respectively. The non-epoxy connecting group does not participate in the polymerization reaction, and only the two epoxy groups participate in the polymerization reaction.

[0100] For example, the chemical structure of a binary epoxy compound is one of the following: [ka] , or [ka] During the ceremony a1, a2, a3, and a4 are all integers, each in the range of 0 to 8.

[0101] For example, embodiments of the present disclosure provide a binary epoxy compound particularly suitable for the preparation of leveling agents. The chemical structural formula of the binary epoxy compound is shown below. [ka]

[0102] When a is 2, the binary epoxy compound is 1,4-butanediol diglycidyl ether; when a is 4, the binary epoxy compound is 1,6-hexanediol diglycidyl ether.

[0103] In some possible embodiments, the chemical structure of the polymer is shown as follows: [ka] During the ceremony 0 ≤ a ≤ 8, 1 ≤ b ≤ 5, 3 ≤ n ≤ 100, and a, b, and n are all integers. R is [ka] or [ka] That is the case.

[0104] For example, a can be 0, 1, 2, 3, 4, 5, 6, 7, or 8; b can be 1, 2, 3, 4, or 5; and n is an integer in the range of 3 to 100.

[0105] In some examples, when the binary epoxy compound is 1,4-butanediol diglycidyl ether and the nitrogen-containing compound is N-(3-aminopropyl)morpholine, the chemical structural formula of the polymer obtained by the preparation is shown below. [ka]

[0106] In some examples, when the binary epoxy compound is 1,4-butanediol diglycidyl ether and the nitrogen-containing compound is N-(3-aminopropyl)pyrrolidine, the chemical structural formula of the polymer obtained by the preparation is shown below. [ka]

[0107] In some examples, when the binary epoxy compound is 1,6-hexanediol diglycidyl ether and the nitrogen-containing compound is N-(3-aminopropyl)morpholine, the chemical structural formula of the polymer obtained by the preparation is shown below. [ka]

[0108] To ensure a sufficient and thorough polymerization reaction, the above polymerization reaction may be carried out under stirring conditions. Alternatively, a nitrogen-containing compound may be gradually added to the binary epoxy compound. This facilitates a thorough and homogeneous mixing of the binary epoxy compound and the nitrogen-containing compound.

[0109] In this embodiment of the present disclosure, the reaction temperature for the polymerization reaction between the binary epoxy compound and the nitrogen-containing compound is in the range of 60°C to 75°C. For example, the reaction temperature includes, but is not limited to, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, 66°C, 67°C, 68°C, 69°C, 70°C, 71°C, 72°C, etc.

[0110] Within the above reaction temperature range, the polymerization reaction can be carried out rapidly and thoroughly, resulting in a fast reaction rate. Furthermore, the reaction temperature can be stably maintained by a water or oil bath.

[0111] The polymerization reaction between a binary epoxy compound and a nitrogen-containing compound is carried out in a solvent. In this embodiment of the present disclosure, the applicable solvent includes at least one of ethanol, methanol, and water. For example, the solvent is ethanol.

[0112] After the polymerization reaction is complete, post-treatment of the reaction system is necessary to remove the solvent and obtain a high-purity leveling agent. Post-treatment includes, but is not limited to, vacuum distillation. For example, a rotary evaporator may be used to perform vacuum rotary evaporation to rapidly remove the solvent from the reaction system.

[0113] According to yet another embodiment of the embodiments of the present disclosure, any one of the aforementioned polymers in the embodiments of the present disclosure is further provided for use in the preparation of leveling agents.

[0114] Any one of the aforementioned polymers is any one of the polymers in the aforementioned embodiments of the polymers and the embodiments of the polymer preparation method in this disclosure.

[0115] The polymers provided in this embodiment of the Disclosure may be used to prepare leveling agents. In some cases, the polymers may be used directly as leveling agents, and the leveling agents obtained by preparation are particularly useful for obtaining very uniform plating. Furthermore, the prepared leveling agents are applicable to obtaining highly coplanar plating at high current densities. In other words, leveling agents prepared based on the polymers provided in this embodiment of the Disclosure can effectively resolve the incompatibility between electroplating production efficiency and the coplanarity of the plating. The electroplating rate can be significantly increased while ensuring the coplanarity of the plating (e.g., the coplanarity of copper pillars). For example, the electroplating rate can be increased to at least more than 2 μm / min and even more than 4 μm / min.

[0116] According to yet another embodiment of the embodiments of the present disclosure, a leveling agent is provided. The leveling agent comprises any one of the aforementioned polymers in the embodiments of the present disclosure.

[0117] Any one of the aforementioned polymers is any one of the polymers in the aforementioned embodiments of the polymers and the embodiments of the polymer preparation method in this disclosure.

[0118] In some examples, the leveling agent has the following chemical structure: [ka] During the ceremony, 0≦a≦8 (and further, 2≦a≦4), 1≦b≦5 (and further, 2≦b≦3), 3≦n≦100 (and further, 5≦n≦40), and a, b, and n are all integers. R is [ka] or [ka] That is the case.

[0119] The leveling agent having the above chemical structure provided in this embodiment of the present disclosure has the function of adjusting the current distribution of the cathode portion (such as a wafer) to be plated at different convection positions (the convection position is the position through which the flowing electroplating solution passes, and the higher the flow rate of the electroplating solution, the higher the convection intensity). The leveling agent has a strongly positive functional group containing N atoms and is strongly positive. Therefore, the N atoms can be characteristically adsorbed in the high current density region of the cathode portion to be plated in order to compete with the anode ion. In this way, the leveling agent suppresses metal deposition (e.g., copper deposition) in the high current density region through steric hindrance and slows down the electroplating rate in the high current density region. Furthermore, the leveling agent has stronger adsorption to the cathode portion to be plated in regions of higher convection intensity and weaker adsorption to the cathode portion to be plated in regions of lower convection intensity. Furthermore, the leveling agent adaptively adjusts the adsorption of the polymer to the plated cathode based on the current density value, providing strong suppression of metal deposition in high current density regions and weak suppression of metal deposition in low current density regions, ultimately enabling the acquisition of highly uniform plating. In particular, the leveling agent can also achieve highly coplanar plating at high current densities. This is of positive significance for improving plating coplanarity while increasing the plating rate at high current densities.

[0120] When the leveling agent provided in this embodiment of the Disclosure is used in an electroplating solution, it is found that the incompatibility between the production efficiency of electroplating and the coplanarity of the plating is effectively resolved. The electroplating rate can be increased to at least 2 μm / min and even further to 4 μm / min while ensuring the coplanarity of the plating (e.g., the coplanarity of copper pillars). Compared to improving the equipment or replacing the electroplating solution system, using the leveling agent provided in this embodiment of the Disclosure to solve the aforementioned technical problems is easier, more convenient, more reliable, and further facilitates the maintenance of the electroplating solution.

[0121] When a is 2, 3, or 4, b is 2 or 3, and n is an integer in the range of 5 to 40, the leveling agent has an appropriate molecular weight and N atomic density, so the leveling agent can obtain a better adsorption capacity to the plated cathode.

[0122] In some examples, a is 2, b is 2, and R is [ka] In that case, the chemical structural formula corresponding to the leveling agent is shown as follows. [ka]

[0123] In some examples, a is 2, b is 3, and R is [ka] In that case, the chemical structural formula corresponding to the leveling agent is shown as follows. [ka]

[0124] In some examples, a is 2, b is 3, and R is [ka] In that case, the chemical structural formula corresponding to the leveling agent is shown as follows. [ka]

[0125] In some examples, a is 4, b is 3, and R is [ka] In that case, the chemical structural formula corresponding to the leveling agent is shown as follows. [ka]

[0126] According to yet another embodiment of the embodiments of the present disclosure, embodiments of the present disclosure further provide a method for preparing a leveling agent. The method for preparing the leveling agent is the same as any one of the polymer preparation methods described above in embodiments of the present disclosure. In other words, the leveling agent expected in this embodiment of the present disclosure can be obtained by using the same method as any one of the polymer preparation methods in embodiments of the present disclosure. Therefore, the method for preparing the leveling agent is not described again herein.

[0127] According to yet another embodiment of the embodiments of the present disclosure, embodiments of the present disclosure further provide an electroplating solution comprising any one of the leveling agents described above.

[0128] Any one of the leveling agents described above in the embodiments of this disclosure can be used in an electroplating solution to obtain a very uniform plating. Furthermore, it is possible to obtain a plating with high coplanarity at a high current density.

[0129] The electroplating solution provided in this embodiment of the present disclosure is found to effectively resolve the incompatibility between electroplating production efficiency and the coplanarity of the plating. It is possible to significantly improve the electroplating speed while ensuring the coplanarity of the plating (e.g., the coplanarity of copper pillars). Using the electroplating solution provided in this embodiment of the present disclosure to solve the aforementioned technical problems is easier, more convenient, more reliable, and further facilitates the maintenance of the electroplating solution compared to improving the equipment or replacing the electroplating solution system.

[0130] In some examples, the chemical structures of leveling agents are shown below: [ka] During the ceremony 0 ≤ a ≤ 8, 1 ≤ b ≤ 5, 3 ≤ n ≤ 100, and a, b, and n are all integers. R is [ka] or [ka] That is the case.

[0131] According to the electroplating solution provided in this embodiment of the present disclosure, a leveling agent having the above-described chemical structure is used, and the leveling agent has the function of adjusting the current distribution of the cathode portion to be plated at different convection positions. In this way, metal deposition in the high current density region can be suppressed through steric hindrance, thus slowing down the electroplating rate in the high current density region. Based on the use of the leveling agent described above, the electroplating solution provided in this embodiment of the present disclosure helps to obtain very uniform plating and helps to improve the usability of the electroplating solution. The electroplating solution is suitable for use at high current densities and can improve the coplanarity of copper pillars while increasing the plating rate at high current densities.

[0132] The electroplating solutions provided in this embodiment of the present disclosure further comprise other components in addition to leveling agents. These other components include metal salts, acidic solutions, water-soluble chlorides, accelerators, inhibitors, and the like.

[0133] In some possible embodiments, embodiments of the present disclosure provide such an electroplating solution. The electroplating solution comprises a metal salt, an acidic solution, a water-soluble chloride, a leveling agent, an accelerator, and an inhibitor. Each component is described further below.

[0134] In the case of metal salts, the metal salt is used as the anode component to form a metal plating on the cathode portion to be plated, and the metal plating is the metal to be plated. Metal salts include, but are not limited to, copper salts, aluminum salts, and silver salts suitable for electroplating. In particular, the metal salt may be a commonly used copper salt. For example, the copper salt may include at least one of copper sulfate, copper cyanide, and copper pyrophosphate. In some examples, the copper salt is copper sulfate.

[0135] The concentration of metal salts in electroplating solutions ranges from 5 g / L to 300 g / L. For example, the concentrations of metal salts in electroplating solutions include, but are not limited to, the following: 10 g / L, 50 g / L, 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L, 150 g / L, 160 g / L, 170 g / L, 180 g / L, 190 g / L, 200 g / L, 210 g / L, 220 g / L, 230 g / L, 240 g / L, 250 g / L, 260 g / L, 270 g / L, 280 g / L, 290 g / L, 300 g / L, etc. Furthermore, the concentration of metal salts in electroplating solutions ranges from, for example, 150 g / L to 250 g / L. The concentration of metal salts is within the above range. This ensures that sufficient metal ions are supplied to the cathode area to be plated, further promoting the complete dissolution of the metal salt into the electroplating solution.

[0136] Acidic solutions are used as electrolytes to promote oxidation-reduction reactions in electroplating processes. In some examples, the acidic solution contains at least one of sulfuric acid, hydrochloric acid, and organic acids. For example, the acidic solution is sulfuric acid, and an acidic solution with a mass concentration ranging from 30% to 60% can be prepared using concentrated sulfuric acid at a mass concentration of 98% and water.

[0137] The concentration of the acidic solution in the electroplating solution ranges from 10 g / L to 300 g / L. For example, the concentration of the acidic solution in the electroplating solution includes, but is not limited to, 10 g / L, 20 g / L, 30 g / L, 40 g / L, 50 g / L, 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L, 150 g / L, 160 g / L, 170 g / L, 180 g / L, 190 g / L, 200 g / L, 250 g / L, 280 g / L, etc. Furthermore, the concentration of the acidic solution in the electroplating solution ranges from, for example, 50 g / L to 150 g / L. The concentration of the acidic solution is within the aforementioned range. This ensures good conductivity of the electroplating solution and further ensures complete dissolution of the metal salt in the electroplating solution to avoid deposition.

[0138] For water-soluble chlorides, they are used as inorganic additives to provide chloride ions and to work in conjunction with inhibitors and accelerators. In some examples, the water-soluble chloride includes at least one of hydrochloric acid, sodium chloride, potassium chloride, and ammonium chloride.

[0139] The concentration of chloride ions is used as a standard, and the concentration of chloride ions in the water-soluble chloride of the electroplating solution is in the range of 1 ppm to 100 ppm, for example, 10 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 90 ppm, or 100 ppm. Also, the concentration of chloride ions in the water-soluble chloride of the electroplating solution is, for example, in the range of 40 ppm to 80 ppm. The concentration of water-soluble chloride is within the above range. This is because the leveling agent, inhibitor, and accelerator each play their appropriate roles effectively in the electroplating solution, further avoiding the generation of chlorine gas at the anode and thus avoiding the formation of side reactions.

[0140] As stated above, the concentration of the leveling agent provided in this embodiment of the present disclosure of the electroplating solution ranges from 0.01 ppm to 1000 ppm. For example, the concentration of the leveling agent includes, but is not limited to, 0.01 ppm, 0.05 ppm, 0.1 ppm, 0.5 ppm, 1 ppm, 5 ppm, 10 ppm, 20 ppm, 50 ppm, 100 ppm, 200 ppm, 300 ppm, 400 ppm, 500 ppm, 600 ppm, 700 ppm, 800 ppm, 900 ppm, etc. Furthermore, the concentration of the leveling agent in the electroplating solution ranges from, for example, 0.1 ppm to 500 ppm, and even further, from 0.1 ppm to 100 ppm. The concentration of the leveling agent is within the above range. This promotes better coordination with other components of the electroplating solution, resulting in strong adaptability to current density and a good uniform plating effect.

[0141] Regarding accelerators, they are used in the electroplating process to form crystal nuclei and improve the uniform plating ability of the electroplating solution. In some examples, the accelerator is at least one of sodium 3,3'-dithiodipropane sulfonate (SPS) and sodium 3-mercaptopropanesulfonate (MPS). The above types of accelerators promote a high-density distribution of the plating, improve the uniform plating ability of the electroplating solution, and make the plating smooth and reflective.

[0142] The concentration of the accelerator in the electroplating solution ranges from 0.01 ppm to 100 ppm. For example, accelerator concentrations include, but are not limited to, 0.01 ppm, 0.05 ppm, 0.08 ppm, 0.1 ppm, 0.2 ppm, 0.3 ppm, 0.5 ppm, 0.6 ppm, 0.8 ppm, 1 ppm, 5 ppm, 10 ppm, 15 ppm, 20 ppm, 25 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 90 ppm, and 100 ppm. Alternatively, the concentration of the accelerator in the electroplating solution may range from 0.05 ppm to 50 ppm, or even from 0.1 ppm to 20 ppm.

[0143] Regarding inhibitors, they are used to increase the electrochemical reaction resistance, thereby achieving grain refinement and inhibiting the growth of plating on the substrate surface. In some examples, the inhibitor includes at least one of polyethylene glycol, polypropylene glycol, PEO-PPO-PEO block copolymer, and PPO-PEO-PPO block copolymer. PPO (Polypropylene Oxide) polyoxypropylene, PEO (Polyethylene oxide) polyoxyethylene, and PEO-PPO-PEO block copolymer are also called polyoxyethylene-polyoxypropylene-polyoxyethylene block copolymer. PPO-PEO-PPO block copolymer is also called polyoxypropylene-polyoxyethylene-polyoxypropylene block copolymer. The aforementioned types of inhibitors are readily adsorbed to the active sites of grain growth. This increases the electrochemical reaction resistance and improves electrochemical polarization, resulting in grain refinement and inhibiting the growth of plating on the substrate surface.

[0144] The concentration of the inhibitor in the electroplating solution ranges from 1 ppm to 2000 ppm. For example, inhibitor concentrations include, but are not limited to, 1 ppm, 5 ppm, 10 ppm, 15 ppm, 20 ppm, 30 ppm, 40 ppm, 50 ppm, 60 ppm, 70 ppm, 80 ppm, 90 ppm, 100 ppm, 200 ppm, 300 ppm, 400 ppm, 500 ppm, 600 ppm, 700 ppm, 800 ppm, 900 ppm, 1000 ppm, and 1500 ppm. Alternatively, the concentration of the inhibitor in the electroplating solution may range from 50 ppm to 1500 ppm, or even from 100 ppm to 1000 ppm.

[0145] According to the electroplating solution provided in this embodiment of the present disclosure, having the aforementioned components, the current distribution in the electroplating process can be effectively adjusted based on the coordination of the metal salt, acidic solution, water-soluble chloride, leveling agent, accelerator, and inhibitor. In this way, the dispersibility and uniform plating ability of the electroplating solution are significantly improved, and highly coplanar plating, such as copper pillars, can be obtained. In particular, the electroplating solution is suitable for use at high current densities, and highly coplanar plating can still be obtained even at high current densities and high plating rates.

[0146] The electroplating solution provided in this embodiment of the present disclosure is applicable to forming a metallic plating of uniform thickness on a substrate. For example, the substrate includes, but is not limited to, printed circuit boards, integrated circuits, semiconductor packages, lead frames, and interconnects. The electroplating solution provided in this embodiment of the present disclosure is applicable to the field of microelectronic packaging. For example, the electroplating solution can be used for copper pillar electroplating in microelectronic packaging interconnects, thereby effectively improving the coplanarity of the copper pillars at high current densities and further effectively improving the lifespan and reliability of the electronic components.

[0147] According to yet another embodiment of the embodiments of the present disclosure, embodiments of the present disclosure further provide a method for electroplating a part to be plated. The aforementioned electroplating solution is used in the method.

[0148] The part to be plated is the cathode part to be plated, and the material of the part to be plated includes, but is not limited to, resin, ceramic, metal, silicon die (i.e., wafer). For example, resin may be used to obtain the cathode part to be plated by preparation, and the cathode part to be plated may be used as a printed circuit board. Alternatively, ceramic may be used to obtain the cathode part to be plated by preparation, and the cathode part to be plated may be used as a semiconductor wafer. Alternatively, metallic silicon may be used to obtain the cathode part to be plated by preparation, and the cathode part to be plated may be used as a wafer.

[0149] Electroplating using the electroplating solution provided in this embodiment of the disclosure can result in highly uniform plating. In particular, highly uniform plating can still be obtained even at high current densities and fast plating speeds. Furthermore, high electroplating efficiency is ensured.

[0150] In some examples, the method for electroplating a part to be plated provided in this embodiment of the present disclosure includes performing electroplating at a current density of 5 ASD or more, for example, 10 ASD or more. Alternatively, electroplating may be performed at a current density of 15 ASD or more, for example, 16 ASD or more, 17 ASD or more, 18 ASD or more, 19 ASD or more, or 20 ASD or more.

[0151] In some examples, a method for electroplating a part to be plated provided in this embodiment of the present disclosure includes performing electroplating at a plating rate of 2 μm / min or more.

[0152] The electroplating method provided in this embodiment of the present disclosure is applicable when used at high current densities to obtain highly coplanar plating.

[0153] In some examples, in this embodiment of the present disclosure, a silicon wafer is used as the cathode to be plated, copper ions are used as the metal to be plated, and the electroplating operation is performed with the aforementioned electroplating solution, as a result, highly coplanar copper pillars can be formed on the silicon wafer. Furthermore, the current density during electroplating is greater than 5ASD, and moreover, the current density is 15ASD or higher. The plating speed exceeds 2 μm / min, and moreover, the plating speed exceeds 4 μm / min.

[0154] The Disclosure will be further described below using more specific embodiments. While several specific embodiments will be described below, it should be understood that the Disclosure may be implemented in various forms and should not be limited to the embodiments described herein. Where no specific technology or conditions are specified in the embodiments, the technology or conditions described in the literature or product specifications of the art will be used as a reference, and reagents or equipment whose manufacturers are not specified may be conventional products available by purchase from the market.

[0155] Embodiment 1 Embodiment 1 provides a polymer, which is obtained by preparation using the following method.

[0156] 3 g of 1,4-butanediol diglycidyl ether is dissolved in 20 ml of ethanol and stirred uniformly to obtain an intermediate mixture. 1.93 g of N-(3-aminopropyl)morpholine is added to this intermediate mixture under stirring conditions and stirred uniformly to obtain the reaction raw material solution.

[0157] The reaction raw material solution is heated to 65°C, and then the polymerization reaction takes place at that temperature. After the polymerization reaction has been carried out for 24 hours, the reaction system is cooled to room temperature, yielding a yellow, viscous solution.

[0158] A yellow, viscous solution is subjected to reduced-pressure rotational evaporation to remove ethanol and obtain a polymer.

[0159] Embodiment 2 Embodiment 2 provides a polymer, which is obtained by preparation using the following method.

[0160] 3 g of 1,4-butanediol diglycidyl ether is dissolved in 20 ml of ethanol and stirred uniformly to obtain an intermediate mixture. 1.9 g of N-(3-aminopropyl)pyrrolidine is added to this intermediate mixture under stirring conditions and stirred uniformly to obtain the reaction raw material solution.

[0161] The reaction raw material solution is heated to 67°C, and then the polymerization reaction takes place at that temperature. After 24 hours of polymerization, the reaction system is cooled to room temperature, yielding a yellow, viscous solution.

[0162] A yellow, viscous solution is subjected to reduced-pressure rotational evaporation to remove ethanol and obtain a polymer.

[0163] Embodiment 3 Embodiment 3 provides a polymer, which is obtained by preparation using the following method.

[0164] 2.8 g of 1,6-hexanediol diglycidyl ether is dissolved in 30 ml of methanol and stirred uniformly to obtain an intermediate mixture. 1.93 g of N-(3-aminopropyl)morpholine is added to this intermediate mixture under stirring conditions and stirred uniformly to obtain the reaction raw material solution.

[0165] The reaction raw material solution is heated to 70°C, and then the polymerization reaction takes place at that temperature. After the polymerization reaction has been carried out for 24 hours, the reaction system is cooled to room temperature, yielding a yellow, viscous solution.

[0166] A yellow, viscous solution is subjected to reduced-pressure rotational evaporation to remove methanol and obtain a polymer.

[0167] Test Cases The polymers provided in Embodiments 1 and 2 are used as leveling agents for electroplating solutions (i.e., each of the aforementioned polymers is a leveling agent). Several electroplating solutions are provided for electroplating and used as test cases (corresponding to Test Case 1, Test Case 2, and Test Case 3, respectively). Correspondingly, several electroplating solutions are also provided for electroplating and used as comparative examples to test the leveling effect of the leveling agents corresponding to Embodiments 1 and 2 for plating at high current densities (corresponding to Comparative Example 1 and Comparative Example 2, respectively).

[0168] The aforementioned electroplating is actually a copper plating process. A silicon wafer (or silicon chip) is used as the cathode, and copper pillars are electroplated onto the silicon wafer. The electroplating process uses a suspended plating method.

[0169] Refer to Table 1 for the formulas of the test cases and comparative examples, the electroplating conditions, and the results of the copper pillar morphology and coplanarity of the copper pillar arrays obtained by electroplating. Copper sulfate in Table 1 is copper sulfate pentahydrate; all chloride ions in Table 1 are provided by sodium chloride; and EPE in Table 1 is a PEO-PPO-PEO block copolymer with a molecular weight of 6000.

[0170] [Table 1]

[0171] The data for "copper pillar uniformity" in Table 1 refers to the value obtained by dividing the difference between the height of the center of the copper pillar and the height of the shoulder of the copper pillar by the height of the shoulder of the copper pillar.

[0172] The data on "surface roughness" in Table 1 shows the smoothness of the copper pillar surface.

[0173] The data for "coplanarity of copper cylinder arrays" in Table 1 refers to the value obtained by dividing the difference between the height of the highest and lowest copper pillars in the electroplated area by the average height of the copper pillars in that area, and then dividing by 2.

[0174] For the morphological structure of the copper pillar obtained in Test Case 1, please refer to Figure 1. For the morphological structure of the copper pillar obtained in Test Case 2, please refer to Figure 2. For the morphological structure of the copper pillar obtained in Test Case 3, please refer to Figure 3. For the morphological structure of the copper pillar obtained in Comparative Example 1, please refer to Figure 4. For the morphological structure of the copper pillar obtained in Comparative Example 2, please refer to Figure 5.

[0175] From the copper plating results in Figures 1 to 3 and Table 1, the electroplating solutions provided in Test Cases 1 to 3 have a maximum load of 15 A / dm 2 Or up to 20A / dm 2 It can be seen that highly coplanar copper pillars can be obtained even at such a current density. Referring to Figures 4 and 5, compared with Comparative Examples 1 and 2, this embodiment of the present disclosure can significantly improve the uniformity of a single copper pillar and the coplanarity of a copper pillar array by adding a leveling agent to the electroplating solution. This confirms that the electroplating solution provided in this embodiment of the present disclosure is useful for obtaining highly uniform copper pillars at high current densities.

[0176] Furthermore, Table 1 shows that when the deposition rate of copper pillars is 4.4 microns / min, the uniformity of the copper pillars can also be maintained within 5% (the theoretical growth rate of copper pillars is approximately 4.4 microns / min when the current density is 20 ASD).

[0177] Please note that the resolution of Figures 1, 2, and 3 may be reduced due to printing or scanning of the original documents, and therefore the differences between Figures 1, 2, and 3 may not be clear. However, it is still evident that the copper pillars shown in Figures 1, 2, and 3 differ in height and diameter.

[0178] Furthermore, the laser confocal microscope images shown in Figures 1, 2, and 3 may lose some resolution due to printing or scanning of the document, and as a result, in some cases the effects of the solution may not be clearly visible from the accompanying drawings in the document. However, the essence of this solution lies in improving the uniformity of the copper pillars and the coplanarity of the copper pillar array by using a specific leveling agent. Therefore, regardless of whether the laser confocal microscope images of the copper pillars shown in Figures 1, 2, and 3 are provided in the embodiments of this application, the aforementioned technical effects can be obtained by analysis based on the technical solution of the embodiments of this application.

[0179] The foregoing explanation is intended solely to help those skilled in the art understand the technical solutions of this disclosure and is not intended to limit the disclosure. Any modifications, equivalent substitutions, or improvements made without departing from the principles of this disclosure shall be within the scope of this disclosure.

Claims

1. A polymer comprising a plurality of repeating units, wherein each repeating unit comprises a binary epoxy compound residue and a nitrogen-containing group. The aforementioned binary epoxy compound residue is a residue formed after the epoxy bond of the binary epoxy compound is ring-opened. The nitrogen-containing group comprises an alkyl group and a dimethylamine group and a nitrogen-containing heterocyclic group attached to the two ends of the alkyl group, respectively, wherein the dimethylamine group is further attached to the binary epoxy compound residue via a single bond. polymer.

2. The polymer according to claim 1, wherein the amount of carbon atoms in the alkyl group is in the range of 1 to 5.

3. The polymer according to claim 1, wherein the nitrogen-containing heterocyclic group is a morpholine group or a pyrrole group.

4. The chemical structural formula of the nitrogen-containing group is, 【Chemistry 1】 or 【Chemistry 2】 Includes, b is an integer such that 1 ≤ b ≤ 5. The polymer according to claim 1.

5. The binary epoxy compound residue comprises a non-epoxy connecting group and two epoxy residues connected to the two ends of the non-epoxy connecting group, The epoxy residue is a residue formed after the epoxy bond has been opened, and the epoxy residue is connected to the dimethylamine group. The polymer according to any one of claims 1 to 4.

6. The chemical structure of the aforementioned binary epoxy compound residue is one of the following chemical structures: 【Transformation 3】 or 【Chemistry 4】 During the ceremony a 1 a 2 a 3 , and a 4 All of them are integers, and each is an integer in the range of 0 to 8. The polymer according to claim 5.

7. The polymer according to any one of claims 1 to 6, wherein the amount of repeating units is in the range of 3 to 100.

8. The chemical structure of the polymer is as follows: 【Transformation 5】 During the ceremony 0 ≤ a ≤ 8, 1 ≤ b ≤ 5, 3 ≤ n ≤ 100, and a, b, and n are all integers. R is 【Transformation 6】 or 【Transformation 7】 That is, The polymer according to claim 7.

9. A method for preparing a polymer, wherein the polymer comprises a plurality of repeating units, each repeating unit comprising a binary epoxy compound residue and a nitrogen-containing group; each nitrogen-containing group comprising an alkyl group and a dimethylamine group and a nitrogen-containing heterocyclic group attached to the two ends of the alkyl group, respectively, wherein the dimethylamine group is further attached to the binary epoxy compound residue via a single bond. The polymer preparation method includes the step of obtaining the polymer by carrying out a polymerization reaction between a binary epoxy compound and a nitrogen-containing compound in a solvent, As the binary epoxy compound residue, a residue formed after the epoxy bond of the binary epoxy compound is opened is used. The nitrogen-containing compound comprises an alkyl group and an amine group and a nitrogen-containing heterocyclic group attached to the two ends of the alkyl group, respectively, wherein the residue formed after the amine group of the nitrogen-containing compound participates in the polymerization reaction is used as the nitrogen-containing group. A method for preparing polymers.

10. The polymer preparation method according to claim 9, wherein the amount of carbon atoms in the alkyl group is in the range of 1 to 5.

11. The polymer preparation method according to claim 9, wherein the nitrogen-containing heterocyclic group is a morpholine group or a pyrrole group.

12. The chemical structural formula of the nitrogen-containing compound is, 【Transformation 8】 or 【Chemistry 9】 Including, in the formula b is an integer such that 1 ≤ b ≤ 5. The polymer preparation method according to claim 9.

13. The polymer preparation method according to any one of claims 9 to 12, wherein the binary epoxy compound comprises a non-epoxy connecting group and two epoxy groups connected to the two ends of the non-epoxy connecting group, respectively.

14. The chemical structural formula of the aforementioned binary epoxy compound is one of the following: 【Chemistry 10】 【Chemistry 11】 or 【Chemistry 12】 During the ceremony a 1 a 2 a 3 , and a 4 All of them are integers, and each is an integer in the range of 0 to 8. The polymer preparation method according to claim 13.

15. A polymer preparation method according to any one of claims 9 to 14, wherein the reaction temperature of the polymerization reaction is in the range of 60°C to 75°C.

16. The polymer preparation method according to any one of claims 9 to 15, wherein the solvent comprises at least one of ethanol, methanol, and water.

17. Use of the polymer according to any one of claims 1 to 8 in the preparation of a leveling agent.

18. A leveling agent, wherein the leveling agent comprises a polymer according to any one of claims 1 to 8.

19. The chemical structure of the aforementioned polymer is shown below: 【Chemistry 13】 During the ceremony 2≦a≦4, 2≦b≦3, and 5≦n≦40, R is 【Chemistry 14】 or 【Chemistry 15】 That is, The leveling agent according to claim 18.

20. A method for preparing a leveling agent, wherein the method for preparing the leveling agent is the same as the polymer preparation method described in any one of claims 9 to 16.

21. An electroplating solution, wherein the electroplating solution contains the leveling agent described in claim 18 or 19.

22. The electroplating solution further comprises a metal salt, an acidic solution, a water-soluble chloride, an accelerator, and an inhibitor. The concentration of the metal salt in the electroplating solution is in the range of 5 g / L to 300 g / L. The concentration of the acidic solution in the electroplating solution is in the range of 10 g / L to 300 g / L. The chloride ion concentration of the water-soluble chloride in the electroplating solution is in the range of 1 ppm to 100 ppm. The concentration of the leveling agent in the electroplating solution is in the range of 0.01 ppm to 1000 ppm. The concentration of the accelerator in the electroplating solution is in the range of 0.01 ppm to 100 ppm. The concentration of the inhibitor in the electroplating solution is in the range of 1 ppm to 2000 ppm. The electroplating solution according to claim 21.

23. The metal salt comprises at least one of copper sulfate, copper cyanide, and copper pyrophosphate. The acidic solution comprises at least one of sulfuric acid, hydrochloric acid, and an organic acid. The water-soluble chloride comprises at least one of hydrochloric acid, sodium chloride, potassium chloride, and ammonium chloride. The electroplating solution according to claim 22.

24. The accelerator comprises at least one of sodium polydisulfide dipropanesulfonate and sodium 3-mercapto-1-propanesulfonate. The inhibitor comprises at least one of polyethylene glycol, polypropylene glycol, PEO-PPO-PEO block copolymer, and PPO-PEO-PPO block copolymer. The electroplating solution according to claim 22 or 23.

25. A method for electroplating a part to be plated, comprising the step of using an electroplating solution according to any one of claims 21 to 24.

26. A method for electroplating a part to be plated according to claim 25, comprising the step of performing electroplating at a current density of 5ASD or more.

27. A method for electroplating a part to be plated according to claim 26, comprising the step of performing electroplating at a current density of 15ASD or more.

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