阅读说明：本技术 一种Fe-Ni-P合金电镀液、Fe-Ni-P合金镀层的电沉积方法及合金镀层 (Fe-Ni-P alloy electroplating solution, Fe-Ni-P alloy coating electrodeposition method and alloy coating ) 是由 高丽茵 刘志权 孙蓉 于 2021-06-23 设计创作，主要内容包括：本申请公开了一种Fe-Ni-P合金电镀液、Fe-Ni-P合金镀层的电沉积方法及合金镀层,属于电子制造技术领域。该电镀液包括主盐、络合剂以及水,络合剂包括双络合剂,双络合剂包括柠檬酸和氨三乙酸,或柠檬酸和氨三乙酸盐,或柠檬酸盐和氨三乙酸,或柠檬酸盐和氨三乙酸盐；双络合剂中,氨三乙酸或氨三乙酸盐的浓度与柠檬酸或柠檬酸盐的浓度之比为0.5～5；其中,柠檬酸或柠檬酸盐的浓度为0.01～0.5mol/L,氨三乙酸或氨三乙酸盐的浓度为0.01～0.5mol/L。本申请通过在电镀液中加入柠檬酸(盐)和氨三乙酸(盐)作为双络合剂,能够增加镀液的电化学极化程度,使制备的Fe-Ni-P合金镀层的矫顽力较低,镀层表面光亮、组织细致,可应用于微电子领域以及半导体功能器件等领域。(The application discloses Fe-Ni-P alloy electroplating solution, an electrodeposition method of a Fe-Ni-P alloy coating and the alloy coating, and belongs to the technical field of electronic manufacturing. The electroplating solution comprises main salt, a complexing agent and water, wherein the complexing agent comprises a double complexing agent, and the double complexing agent comprises citric acid and nitrilotriacetic acid, or citric acid salt and nitrilotriacetic acid; in the double complexing agent, the ratio of the concentration of the nitrilotriacetic acid or the nitrilotriacetic acid salt to the concentration of the citric acid or the citric acid salt is 0.5-5; wherein the concentration of citric acid or citrate is 0.01-0.5 mol/L, and the concentration of nitrilotriacetic acid or nitrilotriacetic acid salt is 0.01-0.5 mol/L. According to the method, citric acid (salt) and nitrilotriacetic acid (salt) are added into the electroplating solution as the double complexing agent, so that the electrochemical polarization degree of the electroplating solution can be increased, the coercivity of the prepared Fe-Ni-P alloy coating is low, the surface of the coating is bright, the structure is fine, and the method can be applied to the fields of microelectronics, semiconductor functional devices and the like.)

1. An Fe-Ni-P alloy electroplating bath comprising a main salt, a complexing agent and water, wherein the complexing agent comprises a double complexing agent comprising citric acid and nitrilotriacetic acid, or said citric acid and nitrilotriacetic acid, or a citrate salt and said nitrilotriacetic acid, or said citrate salt and said nitrilotriacetic acid; in the double complexing agent, the ratio of the concentration of the nitrilotriacetic acid or the nitrilotriacetic acid salt to the concentration of the citric acid or the citric acid salt is 0.5-5; wherein the concentration of the citric acid or the citrate is 0.01-0.5 mol/L, and the concentration of the nitrilotriacetic acid or the nitrilotriacetic acid salt is 0.01-0.5 mol/L.

2. The Fe-Ni-P alloy plating solution as set forth in claim 1, wherein said plating solution further comprises a rare earth element; the rare earth elements comprise rare earth salts or rare earth oxides, and the concentration of the rare earth salts or the rare earth oxides is 0.25-0.4 g/L; the rare earth elements are one or two of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd and Tb.

3. The Fe-Ni-P alloy electroplating bath according to claim 1 or 2, characterized in that the primary salts comprise ferrous salts, nickel salts and hypophosphites; wherein the concentration of the ferrous salt is 0.01-0.5 mol/L, the concentration of the nickel salt is 0.01-0.5 mol/L, and the concentration of the hypophosphite is 0.01-0.3 mol/L.

4. The Fe-Ni-P alloy electroplating bath according to claim 3, wherein the ferrous salt comprises FeSO₄And/or FeCl₂Said nickel salt comprises NiSO₄、Ni(NH₂SO₃)₂And NiCl₂Wherein the hypophosphite comprises NaH₂PO₂。

5. The Fe-Ni-P alloy electroplating bath according to claim 4, wherein the electroplating bath further comprises an antioxidant, a brightener, and a wetting agent; wherein the concentration of the antioxidant is 0.01-5 g/L, the concentration of the brightener is 0.01-5 g/L, and the concentration of the wetting agent is 0.01-5 g/L; wherein the antioxidant comprises ascorbic acid, the brightener comprises sodium saccharin or butynediol, and the wetting agent comprises sodium lauryl sulfate.

6. An electrodeposition method of a Fe-Ni-P alloy plating layer, comprising:

obtaining a Fe-Ni-P alloy electroplating solution, wherein the electroplating solution comprises main salt, a complexing agent and water, the complexing agent comprises a double complexing agent, and the double complexing agent comprises citric acid and nitrilotriacetic acid, or the citric acid and the nitrilotriacetic acid, or the citrate and the nitrilotriacetic acid; in the double complexing agent, the ratio of the concentration of the nitrilotriacetic acid or the nitrilotriacetic acid salt to the concentration of the citric acid or the citric acid salt is 0.5-5; wherein the concentration of the citric acid or the citrate is 0.01-0.5 mol/L, and the concentration of the nitrilotriacetic acid or the nitrilotriacetic acid salt is 0.01-0.5 mol/L;

obtaining a base material subjected to surface treatment;

immersing the substrate in the plating solution, and performing electroplating under a constant voltage condition or a constant current condition to deposit the alloy plating layer on the substrate.

7. The method of claim 6, wherein the substrate comprises a bulk or a thin film of a metal material, a PCB circuit board, and a silicon wafer sputtered with a thin metal layer.

8. The method of claim 7, wherein the content of each element in the Fe-Ni-P alloy plating layer is adjusted by changing any one or more of the content of the main salt, the content of the complexing agent, and the process parameters during the electrodeposition process in the plating solution; wherein the process parameters include the current density, the voltage, the pH of the plating solution, and the temperature of the plating solution.

9. The method of claim 8, wherein the voltage under the constant voltage condition is controlled to be 0.7-4.0V, and the current density under the constant current condition is controlled to be 2.0-9.0A/dm²Controlling the pH value of the electroplating solution to be 2-5 and controlling the temperature of the electroplating solution to be 45-60 ℃.

10. An Fe-Ni-P alloy coating produced by the electrodeposition method according to any one of claims 6 to 9, wherein the alloy coating comprises Fe, Ni and P; wherein, the weight percentage of each element is as follows: 10-85% of Fe, 5-70% of Ni, 70-95% of Fe + Ni and the balance of P;

or the alloy coating comprises Fe, Ni, P and rare earth elements; wherein, the weight percentage of each element is as follows: 10-85% of Fe, 5-70% of Ni, 70-95% of Fe + Ni, 0-2% of rare earth elements and the balance of P.

Technical Field

The application relates to the technical field of electronic manufacturing, in particular to Fe-Ni-P alloy electroplating solution, an electrodeposition method of a Fe-Ni-P alloy coating and the alloy coating.

Background

Inductance is one of the most basic electronic components, and power inductors, chokes, filters, and the like formed by the inductance are essential important components of electronic circuits. If discrete passive components can be integrated through inductors, the size of the final product can be reduced by tens of times or even hundreds of times compared with the current general expectation. Inductance applications require higher saturation induction to improve their current handling capability, high resistivity to reduce eddy current losses, and low coercivity to reduce hysteresis losses.

The atomic magnetic moments of Fe (iron), Co (cobalt) and Ni (nickel) are respectively 2.2 muB, 1.7 muB and 0.6 muB, and the atomic magnetic moments of Fe-Co and Fe-Ni alloys are close to that of pure iron in the range of components with high iron content. Since the wave functions of the 3d electrons of Fe, Co, and Ni overlap each other, the metals and alloys thereof can be made ferromagnetic by direct exchange, and the permeability after alloying is higher than that of pure metals, so that the soft magnetic alloy is mainly based on one or two of the transition metals Fe, Co, and Ni.

The existing Fe-Ni, Fe-Co binary and multi-element alloy soft magnetic materials can be obtained in an electrodeposition mode, the cost is low, the preparation efficiency is high, but the resistivity is low, and in order to further increase the resistivity of the Fe-Ni alloy, a non-metal element P is usually doped. In the prior art, the formula of the chemical plating Fe-Ni-P comprises a system which respectively takes acetic acid (salt), citric acid (salt), glycine and the like as complexing agents. However, most Fe-Ni-P alloys have negative codeposition potential, and the complexing agent cannot effectively adjust the precipitation potential of each metal ion, so that the polarization degree of the plating solution is insufficient, the hydrogen evolution reaction is severe, and the finally obtained Fe-Ni-P plating layer is often high in coercive force, rough in surface and high in stress.

Disclosure of Invention

The technical problem mainly solved by the application is to provide Fe-Ni-P alloy electroplating solution, an electrodeposition method of a Fe-Ni-P alloy coating and the alloy coating, wherein the problem of high coercive force of the Fe-Ni-P coating can be solved by adding citric acid (salt) and nitrilotriacetic acid (salt) into the electroplating solution as double complexing agents.

In order to solve the above technical problems, a first technical solution adopted by the present application is to provide a Fe-Ni-P alloy electroplating solution, which includes a main salt, a complexing agent and water, wherein the complexing agent includes a double complexing agent, and the double complexing agent includes citric acid and nitrilotriacetic acid, or citric acid salt and nitrilotriacetic acid; in the double complexing agent, the ratio of the concentration of the nitrilotriacetic acid or the nitrilotriacetic acid salt to the concentration of the citric acid or the citric acid salt is 0.5-5; wherein the concentration of citric acid or citrate is 0.01-0.5 mol/L, and the concentration of nitrilotriacetic acid or nitrilotriacetic acid salt is 0.01-0.5 mol/L.

Wherein the electroplating solution also comprises rare earth elements; wherein the rare earth elements comprise rare earth salts or rare earth oxides, and the concentration of the rare earth salts or the rare earth oxides is 0.25-0.4 g/L; the rare earth element is one or two of La, Ce, Pr, Nd, Pm, Sm, Eu, Gd and Tb.

Wherein the main salt comprises ferrous salt, nickel salt and hypophosphite; wherein the concentration of the ferrous salt is 0.01-0.5 mol/L, the concentration of the nickel salt is 0.01-0.5 mol/L, and the concentration of the hypophosphite is 0.01-0.3 mol/L.

Wherein the ferrous salt comprises FeSO₄And/or FeCl₂The nickel salt includes NiSO₄、Ni(NH₂SO₃)₂And NiCl₂Wherein the hypophosphite comprises NaH₂PO₂。

Wherein, the electroplating solution further comprises an antioxidant, a brightener and a wetting agent; wherein the concentration of the antioxidant is 0.01-5 g/L, the concentration of the brightener is 0.01-5 g/L, and the concentration of the wetting agent is 0.01-5 g/L; wherein the antioxidant comprises ascorbic acid, the brightener comprises sodium saccharin or butynediol, and the wetting agent comprises sodium lauryl sulfate.

In order to solve the above technical problem, a second technical solution adopted by the present application is to provide an electrodeposition method for an Fe-Ni-P alloy plating layer, comprising: obtaining Fe-Ni-P alloy electroplating solution, wherein the electroplating solution comprises main salt, complexing agent and water, the complexing agent comprises double complexing agent, and the double complexing agent comprises citric acid and nitrilotriacetic acid, or citric acid salt and nitrilotriacetic acid; in the double complexing agent, the ratio of the concentration of the nitrilotriacetic acid or the nitrilotriacetic acid salt to the concentration of the citric acid or the citric acid salt is 0.5-5; wherein the concentration of the citric acid or the citrate is 0.01-0.5 mol/L, and the concentration of the nitrilotriacetic acid or the nitrilotriacetic acid salt is 0.01-0.5 mol/L; obtaining a base material subjected to surface treatment; the substrate is immersed in an electroplating solution and is electroplated under constant voltage conditions or constant current conditions to deposit an alloy coating on the substrate.

The substrate comprises a block or a film of a metal material, a PCB circuit board and a silicon wafer sputtered with a metal thin layer.

Wherein, the content of each element in the Fe-Ni-P alloy coating is adjusted by changing any one or more of the content of main salt in the electroplating solution, the content of complexing agent and process parameters in the electrodeposition process; wherein the process parameters include current density, voltage, pH of the plating solution, and temperature of the plating solution.

Wherein the voltage under the condition of constant voltage is controlled to be 0.7-4.0V, and the current density under the condition of constant current is controlled to be 2.0-9.0A/dm²The pH value of the electroplating solution is controlled to be 2-5, and the temperature of the electroplating solution is controlled to be 45-60 ℃.

In order to solve the technical problems, a third technical scheme adopted by the application is to provide a Fe-Ni-P alloy coating, wherein the Fe-Ni-P alloy coating is prepared by the electro-deposition method, and the alloy coating comprises Fe, Ni and P; wherein, the weight percentage of each element is as follows: 10-85% of Fe, 5-70% of Ni, 70-95% of Fe + Ni and the balance of P; or the alloy coating comprises Fe, Ni, P and rare earth elements; wherein, the weight percentage of each element is as follows: 10-85% of Fe, 5-70% of Ni, 70-95% of Fe + Ni, 0-2% of rare earth elements and the balance of P.

The beneficial effect of this application is: the electroplating solution is added with citric acid (salt) and nitrilotriacetic acid (salt) as double complexing agents, and the double complexing agents and metal ions form more stable complex ions capable of existing in the solution, so that the precipitation potential of each metal ion in the electroplating solution can be adjusted, the electrochemical polarization degree of the electroplating solution is greatly increased, the prepared plating layer has lower disorder degree and fewer internal structural defects, the coercive force of the Fe-Ni-P alloy plating layer is reduced, and the plating layer with a bright surface and a fine structure is obtained.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

FIG. 1 is a schematic flow chart of one embodiment of the electrodeposition method of Fe-Ni-P alloy coating according to the present application;

FIG. 2 is a surface topography of the coatings of examples 1 to 5 of the present application and comparative example 1;

FIG. 3 is a graph showing the results of analyzing the composition of the plating layers in examples 1 to 5 of the present application and comparative example 1;

FIG. 4 is a hysteresis loop diagram of a plating layer in example 3 of the present application;

FIG. 5 is a graph showing a comparison of the hysteresis loop of the plating layer in example 6 of the present application with the hysteresis loop of the plating layer in comparative example 2;

FIG. 6 is a graph showing a comparison of the hysteresis loop of the plating layer in example 6 of the present application with the hysteresis loop of the plating layer in comparative example 3.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The terminology used in the embodiments of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the examples of this application and the appended claims, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, the "plural" includes at least two in general, but does not exclude the presence of at least one.

It should be understood that the term "and/or" as used herein is merely one type of association that describes an associated object, meaning that three relationships may exist, e.g., a and/or B may mean: a exists alone, A and B exist simultaneously, and B exists alone. In addition, the character "/" herein generally indicates that the former and latter related objects are in an "or" relationship.

It should be understood that the terms "comprises," "comprising," or any other variation thereof, as used herein, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

Inductance is one of the most basic electronic components, and power inductors, chokes, filters, and the like formed by the inductance are essential important components of electronic circuits. If discrete passive components can be integrated through inductors, the size of the final product can be reduced by tens of times or even hundreds of times compared with the current general expectation. Inductance applications require higher saturation induction to improve their current handling capability, high resistivity to reduce eddy current losses, and low coercivity to reduce hysteresis losses.

Fe. The magnetic moments of Co and Ni atoms are respectively 2.2 μ B, 1.7 μ B and 0.6 μ B, and the atomic magnetic moments of Fe-Co and Fe-Ni alloys are close to that of pure iron in the range of components with high iron content. Since the wave functions of the 3d electrons of Fe, Co, and Ni overlap each other, the metals and alloys thereof can be made ferromagnetic by direct exchange, and the permeability after alloying is higher than that of pure metals, so that the soft magnetic alloy is mainly based on one or two of the transition metals Fe, Co, and Ni.

The existing Fe-Ni, Fe-Co binary and multi-element alloy soft magnetic materials can be obtained in an electrodeposition mode, the cost is low, the preparation efficiency is high, but the resistivity is low, and in order to further increase the resistivity of the Fe-Ni alloy, a non-metal element P is usually doped. In the prior art, the formula of the chemical plating Fe-Ni-P comprises a system which respectively takes acetic acid (salt), citric acid (salt), glycine and the like as complexing agents. However, most Fe-Ni-P alloys have negative codeposition potential, and the complexing agent cannot effectively adjust the precipitation potential of each metal ion, so that the polarization degree of the plating solution is insufficient, the hydrogen evolution reaction is severe, and the finally obtained Fe-Ni-P plating layer is often high in coercive force, rough in surface and high in stress.

Based on the situation, the application provides the Fe-Ni-P alloy electroplating solution, the electrodeposition method of the Fe-Ni-P alloy coating and the alloy coating, and the problem of high coercive force of the Fe-Ni-P coating can be solved by adding citric acid (salt) and nitrilotriacetic acid as double complexing agents into the electroplating solution.

According to the method, citric acid (salt) and nitrilotriacetic acid (salt) are added into the electroplating solution as the double complexing agent, the double complexing agent and metal ions are utilized to form more stable complex ions capable of existing in the solution, the precipitation potential of each metal ion in the electroplating solution is adjusted, the electrochemical polarization degree of the electroplating solution can be greatly increased, the disorder degree of the prepared coating is lower, and the internal structure defects are fewer, so that the coercive force of the Fe-Ni-P alloy coating is reduced, and the coating with a bright surface and a fine structure is obtained.

The present application will be described in detail below with reference to the drawings and embodiments.

The Fe-Ni-P alloy electroplating solution comprises main salt, complexing agent and water, wherein the complexing agent comprises double complexing agent, and the double complexing agent comprises citric acid (C)₆H₈O₇，Citric Acid，CA) and nitrilotriacetic acid (N (CH)₂COOH)₃Nitrilo triacetic acid, NTA), or citric acid and nitrilotriacetate, or citrate and nitrilotriacetic acid, or citrate and nitrilotriacetate; in the double complexing agent, the ratio of the concentration of the nitrilotriacetic acid or the nitrilotriacetic acid salt to the concentration of the citric acid or the citric acid salt is 0.5-5; wherein the concentration of citric acid or citrate is 0.01-0.5 mol/L, and the concentration of nitrilotriacetic acid or nitrilotriacetic acid salt is 0.01-0.5 mol/L.

Wherein the citrate comprises sodium citrate (C)₆H₅Na₃O₇)。

Specifically, when the ratio of the concentration of the nitrilotriacetic acid or the nitrilotriacetic acid salt to the concentration of the citric acid or the citric acid salt is 0.5-5, the double complexing agent can perform a good complexing effect with metal ions. And the higher the concentration of the nitrilotriacetic acid or nitrilotriacetic salt is, the higher the content of Fe in the finally formed alloy coating is, and the higher the saturation magnetic induction intensity is.

In this embodiment, the primary salts include ferrous salts, nickel salts, and hypophosphite salts; wherein the concentration of the ferrous salt is 0.01-0.5 mol/L, the concentration of the nickel salt is 0.01-0.5 mol/L, and the concentration of the hypophosphite is 0.01-0.3 mol/L.

Wherein the ferrous salt comprises FeSO₄(ferrous sulfate) and/or FeCl₂(ferrous chloride), nickel salts including NiSO₄(Nickel sulfate), Ni (NH)₂SO₃)₂(Nickel sulfamate) and NiCl₂One or two of (nickel chloride), and the hypophosphite comprises NaH₂PO₂(sodium hypophosphite).

Specifically, the non-metallic element P is doped on the basis of the Fe-Ni alloy, so that the resistivity of the alloy coating can be improved. Because the codeposition potential of the Fe-Ni-P alloy is negative, citric acid (salt) and nitrilotriacetic acid are added into the electroplating solution as the double complexing agent, the double complexing agent and metal ions can be utilized to form complex ions, the complex ions are more stable than the existing form of the metal ions before, and the metal is more difficult to deposit from the solution, so that the precipitation potential of each metal ion in the electroplating solution is adjusted, the electrochemical polarization of the electroplating solution is increased, the generated tissue is more fine and smooth, and an Fe-Ni-P alloy coating with lower disorder degree and less internal structural defects is further generated, while the low coercive force is usually benefited by lower disorder degree and less internal structural defects of the coating.

In this embodiment, the electroplating solution further includes an antioxidant, a brightener, and a wetting agent; wherein the concentration of the antioxidant is 0.01-5 g/L, the concentration of the brightener is 0.01-5 g/L, and the concentration of the wetting agent is 0.01-5 g/L; wherein the antioxidant comprises ascorbic acid, the brightener comprises sodium saccharin or butynediol, and the wetting agent comprises sodium lauryl sulfate.

Wherein the electroplating solution also comprises H₃BO₃(boric acid) wherein H₃BO₃The concentration of (b) is 0.25 to 1 mol/L. Specifically, boric acid acts as a buffer to suppress the change in the pH of the plating solution during plating.

In other embodiments, the electroplating bath further comprises a rare earth element (RE); wherein the rare earth elements comprise rare earth salts or rare earth oxides, and the concentration of the rare earth salts or the rare earth oxides is 0.25-0.4 g/L; the rare earth element is one or two of La (lanthanum), Ce (cerium), Pr (praseodymium), Nd (neodymium), Pm (promethium), Sm (samarium), Eu (uranium), Gd (gadolinium) and Tb (terbium).

Specifically, the polarization of the plating solution can be increased by adding a proper amount of rare earth elements.

Different from the prior art, the embodiment adds citric acid (salt) and nitrilotriacetic acid (salt) into the electroplating solution as the double complexing agent, forms more stable complex ions capable of existing in the solution by using the double complexing agent and metal ions, can adjust the precipitation potential of each metal ion in the electroplating solution, greatly increases the electrochemical polarization degree of the electroplating solution, enables the prepared plating layer to have lower disorder degree and fewer internal structure defects, thereby reducing the coercive force of the Fe-Ni-P alloy plating layer and obtaining the plating layer with bright surface and delicate structure. Furthermore, the electroplating solution in the embodiment has the advantages of simple system, high stability, low concentration of each component, low cost and easy popularization, and can be widely applied to the fields of microelectronics, semiconductor functional devices and the like.

Correspondingly, the application provides an electrodeposition method of the Fe-Ni-P alloy coating.

Referring to FIG. 1, FIG. 1 is a schematic flow chart illustrating an embodiment of a method for electrodeposition of a Fe-Ni-P alloy coating according to the present invention. As shown in fig. 1, in the present embodiment, the method includes:

s11: obtaining Fe-Ni-P alloy electroplating solution, wherein the electroplating solution comprises main salt, complexing agent and water, the complexing agent comprises double complexing agent, and the double complexing agent comprises citric acid and nitrilotriacetic acid, or citric acid salt and nitrilotriacetic acid; in the double complexing agent, the ratio of the concentration of the nitrilotriacetic acid or the nitrilotriacetic acid salt to the concentration of the citric acid or the citric acid salt is 0.5-5; wherein the concentration of citric acid or citrate is 0.01-0.5 mol/L, and the concentration of nitrilotriacetic acid or nitrilotriacetic acid salt is 0.01-0.5 mol/L.

In this embodiment, first, the concentrations of the main salt, the complexing agent, and the additive in the plating liquid are selected. Specifically, the main salts include ferrous salts, nickel salts, and hypophosphites; wherein the concentration of ferrous salt is 0.01-0.5 mol/L, the concentration of nickel salt is 0.01-0.5 mol/L, and the concentration of hypophosphite is 0.01-0.3 mol/L; wherein the ferrous salt comprises FeSO₄And/or FeCl₂The nickel salt includes NiSO₄、Ni(NH₂SO₃)₂And NiCl₂Wherein the hypophosphite comprises NaH₂PO₂. The choice and parameters of the bis-complexing agent are as described above. The additives comprise an antioxidant, a brightening agent and a wetting agent; wherein the concentration of the antioxidant is 0.01-5 g/L, the concentration of the brightener is 0.01-5 g/L, and the concentration of the wetting agent is 0.01-5 g/L; wherein the antioxidant comprises ascorbic acid, the brightener comprises sodium saccharin or butynediol, and the wetting agent comprises sodium lauryl sulfate.

In the embodiment, boric acid is dissolved in deionized water at 85 ℃, stirred and dissolved, and then sodium hypophosphite, a complexing agent, an additive and the like are sequentially added. Adjusting the pH value of the obtained mixed solution to 2-5 by using NaOH (sodium hydroxide) and HCl (hydrochloric acid), and adding ferrous salt and nickel salt; after the pH is finely adjusted by HCl, the mixed solution is poured into a volumetric flask to a constant volume to obtain the Fe-Ni-P alloy electroplating solution.

Wherein, after ferrous salt and nickel salt are added, NaOH cannot be used for adjusting the pH value so as to prevent precipitation.

Further, the temperature of the electroplating solution is adjusted to be 45-60 ℃.

In other embodiments, boric acid is dissolved in deionized water at 85 ℃, stirred and dissolved, and then the rare earth element, sodium hypophosphite, a complexing agent, an additive and the like are sequentially added. Adjusting the pH value of the obtained mixed solution to 2-5 by using NaOH (sodium hydroxide) and HCl (hydrochloric acid), and adding ferrous salt and nickel salt; after the pH is finely adjusted by HCl, the mixed solution is poured into a volumetric flask to constant volume to obtain the Fe-Ni-P-RE alloy electroplating solution.

S12: a substrate having undergone surface treatment is obtained.

In this embodiment, the substrate includes a block or a film of a metal material, a PCB, and a silicon wafer sputtered with a thin metal layer.

Wherein the metal comprises copper (Cu), titanium (Ti), aluminum (Al), tantalum (Ta) and titanium-tungsten alloy (Ti-W).

Before the alloy coating is electrodeposited on the base material, the surface of the base body is treated, and dust, grease, oxide and the like which may exist can be removed. Wherein, the substrate is subjected to reduced washing to remove grease; the substrate is acid washed to remove the oxide.

Specifically, the steps of the substrate alkaline washing are as follows: cleaning the surface of the substrate by using deionized water to remove dust; then the substrate is placed in 50 ℃ degreasing alkali liquor to clean the grease on the surface of the substrate. Wherein the oil removing alkali liquor is NaOH and Na₃PO₄(sodium phosphate) mixed solution, the concentration of NaOH is 10g/L, Na₃PO₄The concentration of (A) is 20 g/L; and washing with deionized water after alkaline washing, and blow-drying for later use.

The method for pickling the substrate comprises the following steps: cleaning the surface of the substrate by using deionized water to remove dust; then the substrate is placed in acid washing solution to remove the oxide layer on the surface of the substrate, so as to realize the purpose of surface activation. Wherein the pickling solution is 5% HCl or dilute H₂SO₄(sulfuric acid); and washing with deionized water after acid washing, and blow-drying for later use.

S13: the substrate is immersed in an electroplating solution and is electroplated under constant voltage conditions or constant current conditions to deposit an alloy coating on the substrate.

In this embodiment, before the electroplating, the process parameters of the electrodeposition need to be determined. Wherein the process parameters include current density, voltage, pH of the plating solution, and temperature of the plating solution.

For example, a certain current density is selected and the applied current is calculated based on the surface area to be plated. If there are portions that do not require plating, they may be covered with photoresist, resin, or other insulating treatment.

Further, cathode and anode materials required by electroplating are selected. Wherein, the cathode material is a substrate, the anode material is Fe-Ni alloy, and the content of Fe in the Fe-Ni alloy is 70 wt.%.

In other embodiments, the anode material may also be pure iron balls and pure nickel balls, wherein the volume of the pure iron balls accounts for 60-70%, which is not limited in the present application. Specifically, when the anode material is pure iron balls and pure nickel balls, the anode balls need to be loaded into a titanium basket.

Further, the substrate is immersed in a plating solution, plating is performed under a constant voltage condition or a constant current condition, and a stirring form of cathode oscillation and circulating jet of the plating solution is used during plating.

In this embodiment, the content of each element in the Fe-Ni-P alloy plating layer can be adjusted by changing any one or more of the content of the main salt, the content of the complexing agent, and the process parameters in the electrodeposition process in the electroplating solution, so as to obtain alloy plating layers with different compositions. Specifically, the controllable adjustment of the thermal expansion coefficient, the magnetic property and the electric property of the thin film material can be realized by adjusting the proportion of Fe, Ni, P and RE components in the coating.

Wherein the voltage under the condition of constant voltage is controlled to be 0.7-4.0V, and the current density under the condition of constant current is controlled to be 2.0-9.0A/dm²。

Wherein the electroplating time is controlled to be 5-60 min.

Further, after the plating time is finished, the energization is stopped immediately, the stirring is stopped, and the plating layer and the substrate are taken out. Because the electroplating solution is acidic, the plating layer needs to be repeatedly washed by deionized water to remove the residual electroplating solution on the surface of the plating layer, and the surface of the plating layer is dried by compressed air after the cleaning is finished.

Different from the prior art, the embodiment provides a plating solution system which has a more obvious polarization effect and takes citric acid (salt) and nitrilotriacetic acid (salt) as double complexing agents, so that the prepared plating layer has low disorder degree and less internal structure defects, the coercive force of the Fe-Ni-P alloy plating layer is reduced, and the plating layer with a bright surface and a fine structure is obtained. Furthermore, the electroplating solution in the embodiment has the advantages of simple system, high stability, low concentration of each component, low cost and easy popularization, and can be widely applied to the fields of microelectronics, semiconductor functional devices and the like. In addition, by changing any one or more of the content of the main salt, the content of the complexing agent and the process parameters in the electrodeposition process, alloy coatings with different components can be obtained, so that the application range of the material is expanded.

Accordingly, the present application provides a Fe-Ni-P alloy plating layer, which is made by the above electrodeposition method.

In the present embodiment, the Fe-Ni-P alloy plating layer includes Fe, Ni, and P; wherein, the weight percentage of each element is as follows: 10-85% of Fe, 5-70% of Ni, 70-95% of Fe + Ni and the balance of P; or the alloy coating comprises Fe, Ni, P and rare earth elements; wherein, the weight percentage of each element is as follows: 10-85% of Fe, 5-70% of Ni, 70-95% of Fe + Ni, 0-2% of rare earth elements and the balance of P.

Specifically, the higher the iron content in the Fe-Ni-P alloy plating layer, the higher the saturation induction density thereof. The high resistivity is obtained by non-metal elements, and is generally doped with 5-15% of non-metal elements P, so that the resistivity can be improved by about 10 times.

In the embodiment, the iron content of the alloy coating is high, so that the coating has high saturation magnetic induction intensity; because of doping part of P, the material also has high resistivity.

More importantly, because a plating solution system which has more obvious polarization effect and takes citric acid (salt) and nitrilotriacetic acid as double complexing agents is used in electroplating, the coercive force of the prepared alloy plating layer is lower.

Compared with the prior art, the embodiment provides a plating solution system which has a more obvious polarization effect and takes citric acid (salt) and nitrilotriacetic acid (salt) as double complexing agents, so that the prepared alloy plating layer meets the requirements of magnetic core materials with high saturation magnetic induction intensity, high resistivity and low coercive force, has excellent comprehensive performance, and can be applied to the related electroplating magnetic thin film application fields of advanced integrated circuit packaging, printed circuit board manufacturing and the like.

The following non-limiting examples are provided to facilitate an understanding of the embodiments of the present application and are set forth in the detailed description to provide further explanation of the embodiments of the present application.

Example 1

Obtaining Fe-Ni-P alloy electroplating solution, wherein the components and the concentration of the electroplating solution are as follows: FeSO₄·7H₂O is 0.10mol/L, NiSO₄·6H₂O is 0.10mol/L, NaH₂PO₂0.20mol/L of Nd₂O₃0.25g/L, H₃BO₃0.25mol/L, C₆H₈O₇0.05mol/L, N (CH)₂COOH)₃0.01mol/L, 5g/L ascorbic acid, 2g/L saccharin sodium, 1g/L sodium dodecyl sulfate and the balance water. Performing surface treatment on the wafer sputtered with the TiW seed layer, placing the wafer in a plating tank, using Fe-Ni alloy (Fe70 wt%) as an anode material, adjusting the pH value of the plating solution to 3, controlling the temperature of the plating solution to be 60 ℃, and controlling the current density to be 3.0A/dm²The electroplating time is controlled to be 10 min.

Example 2

Obtaining Fe-Ni-P alloy electroplating solution, wherein the components and the concentration of the electroplating solution are as follows: FeSO₄·7H₂O is 0.10mol/L, NiSO₄·6H₂O is 0.10mol/L, NaH₂PO₂0.20mol/L of Nd₂O₃0.25g/L, H₃BO₃0.25mol/L, C₆H₈O₇0.05mol/L, N (CH)₂COOH)₃0.05mol/L, 5g/L ascorbic acid, 2g/L saccharin sodium,the sodium dodecyl sulfate is 1g/L, and the balance is water. Performing surface treatment on the wafer sputtered with the TiW seed layer, placing the wafer in a plating tank, using Fe-Ni alloy (Fe70 wt%) as an anode material, adjusting the pH value of the plating solution to 3, controlling the temperature of the plating solution to be 60 ℃, and controlling the current density to be 3.0A/dm²The electroplating time is controlled to be 10 min.

Example 3

Obtaining Fe-Ni-P alloy electroplating solution, wherein the components and the concentration of the electroplating solution are as follows: FeSO₄·7H₂O is 0.10mol/L, NiSO₄·6H₂O is 0.10mol/L, NaH₂PO₂0.20mol/L of Nd₂O₃0.25g/L, H₃BO₃0.25mol/L, C₆H₈O₇0.05mol/L, N (CH)₂COOH)₃0.10mol/L, 5g/L ascorbic acid, 2g/L saccharin sodium, 1g/L sodium dodecyl sulfate and the balance water. Performing surface treatment on the wafer sputtered with the TiW seed layer, placing the wafer in a plating tank, using Fe-Ni alloy (Fe70 wt%) as an anode material, adjusting the pH value of the plating solution to 3, controlling the temperature of the plating solution to be 60 ℃, and controlling the current density to be 3.0A/dm²The electroplating time is controlled to be 10 min.

Example 4

Obtaining Fe-Ni-P alloy electroplating solution, wherein the components and the concentration of the electroplating solution are as follows: FeSO₄·7H₂O is 0.10mol/L, NiSO₄·6H₂O is 0.10mol/L, NaH₂PO₂0.20mol/L of Nd₂O₃0.25g/L, H₃BO₃0.25mol/L, C₆H₈O₇0.05mol/L, N (CH)₂COOH)₃0.15mol/L, 5g/L ascorbic acid, 2g/L saccharin sodium, 1g/L sodium dodecyl sulfate and the balance water. Performing surface treatment on the wafer sputtered with the TiW seed layer, placing the wafer in a plating tank, using Fe-Ni alloy (Fe70 wt%) as an anode material, adjusting the pH value of the plating solution to 3, controlling the temperature of the plating solution to be 60 ℃, and controlling the current density to be 3.0A/dm²The electroplating time is controlled to be 10 min.

Example 5

Obtaining Fe-Ni-P alloyThe gold electroplating solution comprises the following components in percentage by concentration: FeSO₄·7H₂O is 0.10mol/L, NiSO₄·6H₂O is 0.10mol/L, NaH₂PO₂0.20mol/L of Nd₂O₃0.25g/L, H₃BO₃0.25mol/L, C₆H₈O₇0.05mol/L, N (CH)₂COOH)₃0.20mol/L, 5g/L ascorbic acid, 2g/L saccharin sodium, 1g/L sodium dodecyl sulfate and the balance water. Performing surface treatment on the wafer sputtered with the TiW seed layer, placing the wafer in a plating tank, using Fe-Ni alloy (Fe70 wt%) as an anode material, adjusting the pH value of the plating solution to 3, controlling the temperature of the plating solution to be 60 ℃, and controlling the current density to be 3.0A/dm²The electroplating time is controlled to be 10 min.

Comparative example 1

Obtaining Fe-Ni-P alloy electroplating solution, wherein the components and the concentration of the electroplating solution are as follows: FeSO₄·7H₂O is 0.10mol/L, NiSO₄·6H₂O is 0.10mol/L, NaH₂PO₂0.20mol/L of Nd₂O₃0.25g/L, H₃BO₃0.25mol/L, C₆H₈O₇0.05mol/L, 5g/L ascorbic acid, 2g/L saccharin sodium, 1g/L sodium dodecyl sulfate and the balance water. Performing surface treatment on the wafer sputtered with the TiW seed layer, placing the wafer in a plating tank, using Fe-Ni alloy (Fe70 wt%) as an anode material, adjusting the pH value of the plating solution to 3, controlling the temperature of the plating solution to be 60 ℃, and controlling the current density to be 3.0A/dm²The electroplating time is controlled to be 10 min.

The surface morphology of the coatings in examples 1 to 5 and comparative example 1 was observed by electron microscopy, and the compositions of the coatings in examples 1 to 5 and comparative example 1 were tested.

Specifically, referring to fig. 2 and 3, fig. 2 is a surface topography of the plating layers in examples 1 to 5 and comparative example 1 of the present application, and fig. 3 is a composition analysis result of the plating layers in examples 1 to 5 and comparative example 1 of the present application. As can be seen from the graphs in FIGS. 2 and 3, only the content of the nitrilotriacetic acid is changed, other conditions are not changed, and when the content of the nitrilotriacetic acid is increased from 0mol/L to 0.20mol/L, the surface of the coating has no defect to no obvious defect, which shows that the brightness of the coating is gradually improved, and the texture is finer; meanwhile, the content of Fe in the alloy coating is increased from 12 wt.% to 80 wt.%, and the content of Ni is reduced from 70 wt.% to 5 wt.%, so that the composition of the coating can be adjusted within a larger range by adjusting the content of nitrilotriacetic acid, and the higher the content of nitrilotriacetic acid is, the higher the content of Fe is.

Further, in example 3, when nitrilotriacetic acid was 0.15mol/L, the coating composition was fes 76.80wt.%, ni 10.85wt.%, p 12.35wt.%. A hysteresis loop of the plating layer in example 3 was obtained. Specifically, referring to fig. 4, fig. 4 is a schematic hysteresis loop diagram of the plating layer in embodiment 3 of the present application. As shown in fig. 4, the saturation magnetic induction of the plating layer was 1.3T, and the coercivity was 0.8Oe, which indicates that the saturation magnetic induction of the plating layer was high when the Fe content was high, and also indicates that the coercivity of the plating layer was low after the plating solution was added with nitrilotriacetic acid to form a bis-complexing agent.

Example 6

Obtaining Fe-Ni-P alloy electroplating solution, wherein the components and the concentration of the electroplating solution are as follows: FeSO₄·7H₂O is 0.50mol/L, NiSO₄·6H₂O is 0.50mol/L, NaH₂PO₂0.01mol/L of Gd₂O₃0.25g/L, H₃BO₃0.50mol/L, C₆H₈O₇0.20mol/L, N (CH)₂COOH)₃0.20mol/L, 5g/L ascorbic acid, 5g/L saccharin sodium, 5g/L sodium dodecyl sulfate, and the balance water. Performing surface treatment on the wafer sputtered with the Ti/Cu seed layer, placing the wafer in a plating tank, using pure iron balls and pure nickel balls (the volume of the pure iron balls accounts for 60-70%) as anode materials, adjusting the pH value of the plating solution to 5, controlling the temperature of the plating solution to be 45 ℃, and controlling the current density to be 6.0A/dm²The electroplating time is controlled to be 20 min.

Comparative example 2

Obtaining Fe-Ni-P alloy electroplating solution, wherein the components and the concentration of the electroplating solution are as follows: FeSO₄·7H₂O is 0.50mol/L, NiSO₄·6H₂O is 0.50mol/L, H₃BO₃0.50mol/L, 5g/L ascorbic acid,5g/L of saccharin sodium, 5g/L of sodium dodecyl sulfate and the balance of water. Performing surface treatment on the wafer sputtered with the Ti/Cu seed layer, placing the wafer in a plating tank, using pure iron balls and pure nickel balls (the volume of the pure iron balls accounts for 60-70%) as anode materials, adjusting the pH value of the plating solution to 5, controlling the temperature of the plating solution to be 45 ℃, and controlling the current density to be 6.0A/dm²The electroplating time is controlled to be 20 min.

Comparative example 3

Obtaining Fe-Ni-P alloy electroplating solution, wherein the components and the concentration of the electroplating solution are as follows: FeSO₄·7H₂O is 0.50mol/L, NiSO₄·6H₂O is 0.50mol/L, NaH₂PO₂0.01mol/L of Gd₂O₃0.25g/L, H₃BO₃0.50mol/L, C₆H₈O₇0.20mol/L, 5g/L ascorbic acid, 5g/L saccharin sodium, 5g/L sodium dodecyl sulfate, and the balance water. Performing surface treatment on the wafer sputtered with the Ti/Cu seed layer, placing the wafer in a plating tank, using pure iron balls and pure nickel balls (the volume of the pure iron balls accounts for 60-70%) as anode materials, adjusting the pH value of the plating solution to 5, controlling the temperature of the plating solution to be 45 ℃, and controlling the current density to be 6.0A/dm²The electroplating time is controlled to be 20 min.

The compositions of the coatings in example 6 and comparative examples 2 and 3 were tested, wherein the compositions of the coatings in example 6 were Fe 80.14 wt.%, Ni 9.36 wt.%, P10.30 wt.%, gd0.20wt.%; the composition of the coating in comparative example 2 was Fe 50 wt.%, Ni 50 wt.%; the composition of the coating in comparative example 3 was Fe 33 wt.%, Ni 54 wt.%, P11 wt.%, Gd 2 wt.%.

Hysteresis loops of the plating layers in example 6 and comparative examples 2 and 3 were obtained and subjected to comparative analysis. Specifically, referring to fig. 5 and 6, fig. 5 is a schematic diagram showing a comparison between a hysteresis loop of a plating layer in example 6 of the present application and a hysteresis loop of a plating layer in comparative example 2, and fig. 6 is a schematic diagram showing a comparison between a hysteresis loop of a plating layer in example 6 of the present application and a hysteresis loop of a plating layer in comparative example 3.

As shown in fig. 5, the saturation magnetic induction of the plating layer in example 6 is 1.5T, the coercive force is 0.6Oe, and the saturation magnetic induction of the plating layer in comparative example 2 is 1.3T, and the coercive force is 2Oe, which indicates that when sodium hypophosphite is doped on the basis of an iron-nickel plating solution, citric acid and nitrilotriacetic acid are added as a double complexing agent, so that the polarization of the plating solution can be greatly increased, and a higher saturation magnetic induction and a lower coercive force can be obtained while an Fe-Ni-P co-deposited thin film is obtained. As shown in fig. 6, the saturation magnetic induction of the plating layer in comparative example 3 is 1.1T, and the coercive force is 7Oe, which indicates that when sodium hypophosphite is doped on the basis of an iron-nickel plating solution, only citric acid is added as a complexing agent, even if rare earth elements are added, the polarization of the plating solution cannot be greatly increased, and the content of Fe in the plating layer is also low, so that the saturation magnetic induction of the obtained Fe-Ni-P co-deposited film is low, and the coercive force is large.

Further, the apparent morphology of the coatings in example 6 and comparative examples 2 and 3 was observed under a microscope, and it was found that the coatings in example 6 and comparative example 2 had bright surfaces and no obvious defects, while the coatings in comparative example 3 had whitish surfaces and cracks, indicating that when sodium hypophosphite was doped on the basis of an iron-nickel plating solution, citric acid and nitrilotriacetic acid were added as a double complexing agent, enabling the prepared coatings to have low disorder and fewer internal structural defects.

Compared with the prior art, citric acid (salt) and nitrilotriacetic acid (salt) are added into the electroplating solution to serve as double complexing agents, the double complexing agents and metal ions are utilized to form more stable complex ions capable of existing in the solution, the precipitation potential of each metal ion in the electroplating solution can be adjusted, the electrochemical polarization degree of the electroplating solution is greatly increased, the prepared coating is low in disorder degree and few in internal structure defects, the coercive force of the Fe-Ni-P alloy coating is reduced, and the coating with a bright surface and a delicate structure is obtained. Furthermore, the electroplating solution in the embodiment has the advantages of simple system, high stability, low concentration of each component, low cost and easy popularization, and can be widely applied to the fields of microelectronics, semiconductor functional devices and the like.

The above description is only for the purpose of illustrating embodiments of the present application and is not intended to limit the scope of the present application, and all modifications of equivalent structures and equivalent processes, which are made by the contents of the specification and the drawings of the present application or are directly or indirectly applied to other related technical fields, are also included in the scope of the present application.