Permalloy wafer electroplating solution formula based on magnetic sensor and preparation method

Abstract

The invention discloses a permalloy wafer electroplating solution formula based on a magnetic sensor and a preparation method. The permalloy wafer electroplating solution formula is prepared from the following raw materials in parts by mass: 150-200 parts of nickel-containing chemicals, 30-40 parts of iron-containing chemicals, 5-10 parts of a pH regulator, 0.1-5 parts of a brightener, 0.1-5 parts of a leveling agent, 0.01-0.05 part of a defoaming agent, 2-5 parts of a surfactant, 0.01-0.02 part of an oxygen discharging additive and 500-800 parts of deionized water. The method comprises the following steps: firstly, adding deionized water, and then sequentially adding the nickel-containing chemical, the iron-containing chemical and the defoaming agent; and then adding deionized water into another container, then adding a brightener, a leveling agent and a surfactant, and combining and adjusting the pH value. Aiming at the problem of oxidation of the permalloy electroplating solution, the oxygen removal additive is added to remove oxygen contained in the electroplating solution and weaken oxidation of the permalloy electroplating solution, so that the chemical performance of the electroplating solution is more stable, and meanwhile, the surfactant is added, so that a bright and stable solution system can be formed when various component chemicals of a wafer are dissolved.

Description

Technical Field

[0001] The invention relates to the technical field of sensor chip electroplating, and in particular to a formula and a configuration method of a permalloy wafer electroplating solution based on a magnetic sensor. Background Art

[0002] Magnetic sensor chips can convert magnetic signal changes caused by external factors such as magnetic field, current, stress strain, temperature and light into electrical signals, thereby detecting the corresponding physical quantities. They are used to measure parameters such as current, position, angle and speed, and Permalloy is an alloy composed of about 80% nickel and 20% iron. It is the core film layer of magnetic sensors and is therefore widely used in various magnetic sensors.

[0003] In Hall effect sensors, Permalloy is used to enhance the magnetic field and provide higher signal sensitivity. It can be used in current sensors, position sensors, and speed sensors. Usually, the Permalloy of magnetic sensors is prepared by wafer electroplating to make the alloy film layer have better uniformity and higher quality.

[0004] Since the electroplating of Permalloy requires controlling the concentration of multiple metal ions to ensure the accurate ratio of alloy components (80% nickel, 20% iron), and because the deposition potentials of different metal ions are different, the deposition rates of different metals are also different, which easily leads to uneven composition during the electroplating process. In addition, the existing Permalloy electroplating solution has poor chemical stability and is easily oxidized and discolored in the air, which makes the electroplating solution ineffective. In addition, the stress of the existing nickel-iron metal coating is large. When the coating thickness is thick, it is easy to crack, fall off and wrinkle, and even cause the substrate to warp too much and split. Therefore, a formula and configuration method of Permalloy wafer electroplating solution based on magnetic sensors are proposed. Summary of the invention

[0005] The object of the present invention is to provide a formula and a configuration method of a Permalloy wafer electroplating solution based on a magnetic sensor to solve the problems raised in the above background technology.

[0006] To achieve the above-mentioned purpose, the present invention provides the following technical solution: a formula of a Permalloy wafer electroplating solution based on a magnetic sensor is prepared by the following raw materials in parts by mass: 150-200 parts of nickel-containing chemicals, 30-40 parts of iron-containing chemicals, 5-10 parts of a pH regulator, 0.1-5 parts of a brightener, 0.1-5 parts of a leveler, 0.01-0.05 parts of a defoaming agent, 2-5 parts of a surfactant, 0.01-0.02 parts of an oxygen removal additive and 500-800 parts of deionized water.

[0007] Preferably, the nickel-containing chemicals include one or more of nickel sulfamate, nickel chloride, nickel borate, nickel acetate and nickel phosphate.

[0008] Preferably, the iron-containing chemical comprises one or more of ferrous disulfide, ferrous chloride, ferrous oxalate, ammonium ferrous sulfate, ferric sulfate and ferric chloride.

[0009] Preferably, the pH regulator includes one or more of sulfuric acid, hydrochloric acid, phosphoric acid, acetic acid, nitric acid, sodium bicarbonate, potassium citrate and citric acid.

[0010] Preferably, the brightener includes one or more of polyethylene imine alkyl compounds, sodium polyoxyethylene ether sulfonate, polyethylene glycol, formaldehyde and potassium aminosulfonate.

[0011] Preferably, the leveler includes one or more of phthalocyanine, Janus green, butynediol and coumarin.

[0012] Preferably, the defoaming agent includes one or more of polydimethylsiloxane, polysiloxane, copolymers of polyoxyethylene and polyoxypropylene, ethyl stearate, octanol, decanol and polyether siloxane copolymers.

[0013] Preferably, the surfactant comprises one or more of alkyl ethyl sulfonate and alkyl benzene sulfonate.

[0014] Preferably, the oxygen removal additive includes one or more of sodium sulfite, sodium bisulfite and ethylenediaminetetraacetic acid.

[0015] The method for configuring the formula of the permalloy wafer electroplating solution based on the magnetic sensor is prepared by adopting the electroplating solution formula, and is characterized in that the electroplating solution preparation method comprises the following steps:

[0016] S1, according to the mass fraction occupied by deionized water, add 2 / 3 volume of deionized water into the spare tank, then add nickel-containing chemicals, iron-containing chemicals and defoaming agent in sequence, stir at a speed of 80-110r / min until completely dissolved, and after complete dissolution, stir at a speed of 30-60r / min for 1.5-2h and let stand overnight;

[0017] S2, add 1 / 15-11 / 10 of the remaining deionized water into another container, then add brightener, leveling agent and surfactant and stir at a speed of 80-110r / min until completely dissolved, and introduce the mixed solution into the standby tank after S1 has been left to stand;

[0018] S3, add oxygen removal additive to the solution of S1 and S2, and stir at a speed of 30-40r / min for 45-65min;

[0019] S4, adding a pH regulator to the solution after adding the oxygen removal additive, and adjusting the pH to 4;

[0020] S5, adding the remaining mass fraction of deionized water into the solution after adjusting the pH value, stirring evenly at a speed of 30-40 r / min to obtain an electroplating solution.

[0021] Technical effects and advantages of the present invention:

[0022] (1) The present invention addresses the oxidation problem of Permalloy electroplating solution by adding an oxygen-removing additive to remove oxygen contained in the electroplating solution, thereby weakening the oxidation of the Permalloy electroplating solution and making the chemical properties of the electroplating solution more stable. At the same time, a surfactant is added to allow the various component chemicals of the wafer to dissolve to form a bright and stable solution system.

[0023] (2) To solve the problem of excessive stress in nickel-iron, the present invention adopts one or more chemicals selected from nickel sulfamate, nickel borate, nickel acetate, nickel chloride and nickel phosphate with relatively small coating stress as the source of nickel in the nickel-iron coating. The nickel coating has relatively small internal stress, is smooth and uniform, and has good adhesion and wear resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The present invention is a flow chart of the electroplating solution configuration operation. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0026] Embodiment 1, the present invention provides a formula of Permalloy wafer electroplating solution based on magnetic sensor, which is prepared by the following raw materials in parts by mass: 150-200 parts of nickel-containing chemicals, 30-40 parts of iron-containing chemicals, 5-10 parts of pH regulator, 0.1-5 parts of brightener, 0.1-5 parts of leveler, 0.01-0.05 parts of defoaming agent, 2-5 parts of surfactant, 0.01-0.02 parts of oxygen removal additive and 500-800 parts of deionized water.

[0027] Specifically, the nickel-containing chemicals include one or more of nickel sulfamate, nickel chloride, nickel borate, nickel acetate and nickel phosphate.

[0028] It should be noted that nickel sulfamate is mainly used for electroplating, catalysts and as a raw material for nickel, and nickel sulfamate can provide nickel ions in the electroplating solution to promote the deposition of nickel; nickel chloride is often used to prepare electroplating solutions, catalysts and as a raw material in other chemical reactions. Nickel chloride provides nickel ions during the electroplating process and has good solubility; nickel borate is usually a salt of nickel and boric acid. The specific chemical formula depends on its specific form. Nickel borate is used as a buffer and stabilizer in some electroplating solutions to help control the pH value of the electroplating solution; nickel acetate is often used in electroplating solutions to provide nickel ions and improve the gloss and adhesion of the coating; nickel phosphate is often used in the nickel plating process as an additive to help improve the performance and corrosion resistance of the coating; after the nickel layer is made of the above-mentioned nickel material, the nickel coating has a small internal stress, and the coating is smooth and uniform, and has good adhesion and wear resistance.

[0029] Specifically, the iron-containing chemicals include one or more of ferrous disulfide, ferrous chloride, ferrous oxalate, ferrous ammonium sulfate, ferric sulfate and ferric chloride.

[0030] It should be noted that ferrous disulfide is an ore mineral, usually used to extract iron and other raw materials in chemical reactions; ferrous chloride is often used in water treatment, printing and dyeing, chemical synthesis and electroplating. It is a strong reducing agent that can provide ferrous ions; ferrous oxalate is often used as a standard substance in analytical chemistry and can also be used to synthesize other iron compounds. It is also used as a reducing agent; ammonium ferrous sulfate (also known as Mohr's salt) is often used in analytical chemistry, catalysis and water treatment. It is a stable source of iron; ferric sulfate is widely used in agriculture (to increase the iron content of soil), water treatment, pharmaceuticals and chemical synthesis. It is also often used as a source of iron ions; ferric chloride is a strong acidic compound, often used in water treatment, etching of printed circuit boards, catalysts and chemical synthesis. It can act as an oxidant and can also provide iron ions.

[0031] Specifically, the pH regulator includes one or more of sulfuric acid, hydrochloric acid, phosphoric acid, acetic acid, nitric acid, sodium bicarbonate, potassium citrate and citric acid.

[0032] It should be noted that pH regulators are chemical substances used to adjust and control the pH value of a solution. According to their properties, pH regulators can be divided into acidic and alkaline regulators. In this formula, the pH value of the solution can be adjusted to 4 through the flexible selection of acidic and alkaline pH regulators.

[0033] Specifically, the brightener includes one or more of polyethylene imine alkyl compounds, sodium polyoxyethylene ether sulfonate, polyethylene glycol, formaldehyde and potassium aminosulfonate.

[0034] It should be noted that in the electroplating process, brighteners are important additives used to improve the gloss and quality of the surface of the electroplated layer. Polyethyleneimine alkyl compounds have good surface activity and can improve the gloss and uniformity of the metal electroplated layer. They reduce the surface tension of the electroplating solution and promote the uniform deposition of metal ions, thereby improving the quality of the coating. Sodium polyoxyethylene ether sulfonate can effectively reduce the surface tension of the electroplating solution and enhance the gloss of the coating. It plays a wetting and dispersing role in the electroplating process, helping to reduce precipitation and bubbles, thereby improving the appearance of the coating. Polyethylene glycol is a non-ionic surfactant with good wettability and dispersibility. It can improve the gloss and uniformity of the coating, and at the same time help to improve the adhesion and corrosion resistance of the coating. Formaldehyde is used as a reducing agent to promote the reduction and deposition of metal ions, and also helps to improve the gloss and hardness of the coating. Potassium sulfamate is a compound containing amino and sulfonic acid groups that can improve the gloss and smoothness of the electroplated layer. It acts as an auxiliary agent in the electroplating solution and can improve the quality appearance of the coating.

[0035] Specifically, the leveler includes one or more of phthalocyanine, janacyanin green, butynediol and coumarin.

[0036] It should be noted that in the electroplating solution, the leveling agent is an important additive used to improve the flatness and smoothness of the coating surface. Phthalocyanine compounds are usually used as colorants or dyes, but in some electroplating processes, especially in copper and nickel plating, they can be used as leveling agents. Phthalocyanine can improve the flatness and gloss of the coating by interacting with metal ions. Janus green is a dye that is mainly used for biological staining and microscopy, but in some cases, it can also be used as a leveling agent. Its structure can affect the surface tension of the electroplating solution, making the coating more uniform and smooth. Butynediol is a diol that can be used as a leveling agent in the electroplating solution. It can improve the uniformity and smoothness of the coating and promote the deposition of metal ions to a certain extent. Coumarin is an organic compound with good light absorption properties. In the electroplating solution, it can be used as a leveling agent to help improve the flatness and gloss of the coating. Coumarin can also play a role in inhibiting uneven deposition in some electroplating processes.

[0037] Specifically, the defoaming agent includes one or more of polydimethylsiloxane, polysiloxane, copolymers of polyoxyethylene and polyoxypropylene, ethyl stearate, octanol, decanol and polyether siloxane copolymers.

[0038] Specifically, the surfactant includes one or more of alkylethyl sulfonate and alkylbenzene sulfonate.

[0039] It should be noted that alkyl ethyl sulfonate (AES) and alkyl benzene sulfonate (LAS) are anionic surfactants. AES is a type of nonionic and anionic mixed surfactant with good detergency and foaming properties. They can help reduce surface tension in the plating solution, improve the fluidity of the liquid, and thus enhance the wettability of the liquid to the wafer surface.

[0040] LAS is one of the most commonly used anionic surfactants with excellent detergency and biodegradability. In electroplating applications, LAS can effectively disperse solid particles, maintain the uniformity of the electroplating solution, and enhance the stability and gloss of the solution. The main functions of these two surfactants in the electroplating process include: improving the wettability of the metal surface to ensure uniform coverage of the solution; improving the stability of the electroplating solution to prevent precipitation and foam formation; enhancing the gloss of the electroplated layer to ensure the appearance and performance of the final product.

[0041] Specifically, the oxygen removal additive includes one or more of sodium sulfite, sodium bisulfite and ethylenediaminetetraacetic acid.

[0042] It should be noted that sodium sulfite and sodium bisulfite are sulfites, which can effectively remove oxygen from the solution and prevent oxidation reactions; ethylenediaminetetraacetic acid (EDTA) can not only complex metal ions, but also inhibit oxidation reactions to a certain extent. By setting up oxygen-removing additives, the oxygen dissolved in the plating solution is removed, so that the oxygen in the solution is reduced, the oxidation rate of the plating solution is reduced, and the performance of the plating solution is more stable, so the plating solution can be stored for 1-2 years without deterioration.

[0043] Embodiment 2, the present invention provides as follows Figure 1 The configuration method of the permalloy wafer electroplating solution formula based on the magnetic sensor shown is configured using the electroplating solution formula of the first embodiment. The electroplating solution configuration method includes the following steps:

[0044] S1, according to the mass fraction occupied by deionized water, add 2 / 3 volume of deionized water into the spare tank, then add nickel-containing chemicals, iron-containing chemicals and defoaming agent in sequence, stir at a speed of 80-110r / min until completely dissolved, and after complete dissolution, stir at a speed of 30-60r / min for 1.5-2h and let stand overnight;

[0045] S2, add 1 / 15-11 / 10 of the remaining deionized water into another container, then add brightener, leveling agent and surfactant and stir at a speed of 80-110r / min until completely dissolved, and introduce the mixed solution into the standby tank after S1 has been left to stand;

[0046] S3, add oxygen removal additive to the solution of S1 and S2, and stir at a speed of 30-40r / min for 45-65min;

[0047] S4, adding a pH regulator to the solution after adding the oxygen removal additive, and adjusting the pH to 4;

[0048] S5, adding the remaining mass fraction of deionized water into the solution after adjusting the pH value, stirring evenly at a speed of 30-40 r / min to obtain an electroplating solution.

[0049] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A formula of a permalloy wafer electroplating solution based on a magnetic sensor, characterized in that: The following raw materials are prepared in parts by mass: 150-200 parts of nickel-containing chemicals, 30-40 parts of iron-containing chemicals, 5-10 parts of pH regulators, 0.1-5 parts of brighteners, 0.1-5 parts of levelers, 0.01-0.05 parts of defoamers, 2-5 parts of surfactants, 0.01-0.02 parts of oxygen removal additives and 500-800 parts of deionized water.

2. The magnetic sensor-based permalloy wafer electroplating solution formulation according to claim 1, characterized in that: The nickel-containing chemicals include one or more of nickel sulfamate, nickel chloride, nickel borate, nickel acetate and nickel phosphate.

3. The magnetic sensor-based permalloy wafer electroplating solution formulation according to claim 1, characterized in that: The iron-containing chemicals include one or more of ferrous disulfide, ferrous chloride, ferrous oxalate, ferrous ammonium sulfate, ferric sulfate and ferric chloride.

4. The magnetic sensor-based permalloy wafer electroplating solution formulation according to claim 1, characterized in that: The pH regulator includes one or more of sulfuric acid, hydrochloric acid, phosphoric acid, acetic acid, nitric acid, sodium bicarbonate, potassium citrate and citric acid.

5. The magnetic sensor-based permalloy wafer electroplating solution formulation according to claim 1, characterized in that: The brightener comprises one or more of polyethylene imine alkyl compounds, sodium polyoxyethylene ether sulfonate, polyethylene glycol, formaldehyde and potassium aminosulfonate.

6. The magnetic sensor-based permalloy wafer electroplating solution formulation according to claim 1, characterized in that: The leveler includes one or more of phthalocyanine, Janus green, butynediol and coumarin.

7. The magnetic sensor-based permalloy wafer electroplating solution formulation according to claim 1, characterized in that: The defoaming agent includes one or more of polydimethylsiloxane, polysiloxane, copolymers of polyoxyethylene and polyoxypropylene, ethyl stearate, octanol, decyl alcohol and polyether siloxane copolymer.

8. The magnetic sensor-based permalloy wafer electroplating solution formulation according to claim 1, characterized in that: The surfactant includes one or more of alkyl ethyl sulfonate and alkyl benzene sulfonate.

9. The magnetic sensor-based permalloy wafer electroplating solution formulation according to claim 1, characterized in that: The oxygen removal additive includes one or more of sodium sulfite, sodium bisulfite and ethylenediaminetetraacetic acid.

10. A method for configuring a permalloy wafer electroplating solution formula based on a magnetic sensor, comprising configuring the electroplating solution formula according to any one of claims 1 to 9, characterized in that: The electroplating solution preparation method comprises the following steps: S1, according to the mass fraction occupied by deionized water, add 2 / 3 volume of deionized water into the spare tank, then add nickel-containing chemicals, iron-containing chemicals and defoaming agent in sequence, stir at a speed of 80-110r / min until completely dissolved, and after complete dissolution, stir at a speed of 30-60r / min for 1.5-2h and let stand overnight; S2, add 1 / 15-11 / 10 of the remaining deionized water into another container, then add brightener, leveling agent and surfactant and stir at a speed of 80-110r / min until completely dissolved, and introduce the mixed solution into the standby tank after S1 has been left to stand; S3, add oxygen removal additive to the solution of S1 and S2, and stir at a speed of 30-40r / min for 45-65min; S4, adding a pH regulator to the solution after adding the oxygen removal additive, and adjusting the pH to 4; S5, adding the remaining mass fraction of deionized water into the solution after adjusting the pH value, stirring evenly at a speed of 30-40 r / min to obtain an electroplating solution.

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