Electronickelling method for IGBT (Insulated Gate Bipolar Translator) heat dissipation substrate

Abstract

The invention provides a nickel electroplating method for an IGBT (Insulated Gate Bipolar Translator) heat dissipation substrate, which comprises the following steps of: sequentially carrying out cleaning, chemical polishing and sand blasting on the heat dissipation substrate to obtain a pretreated substrate; carrying out nickel pre-plating treatment by taking the pretreated substrate as a cathode and nickel as an anode to obtain a pre-plated substrate; and carrying out nickel plating treatment by taking the pre-plated substrate as a cathode and nickel as an anode to obtain a nickel-plated substrate. According to the method provided by the invention, the high-quality nickel layer is electroplated on the surface of the heat dissipation substrate by pretreating the surface of the heat dissipation substrate, improving the surface state of the heat dissipation substrate and combining pre-plating activation and nickel plating processes, and particularly, the nickel plating layer with high uniformity and high binding force is formed on the surface of a needle type heat dissipation substrate, so that the performance of the heat dissipation substrate is guaranteed.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of surface treatment, and relates to a nickel electroplating method, in particular to a nickel electroplating method for an IGBT heat dissipation substrate. BACKGROUND

[0002] As a core power switching device of modern power electronic systems, insulated gate bipolar transistor (IGBT) will generate a large amount of heat during high power density operation. If the heat cannot be dissipated in time, it will lead to high temperature rise of the device, efficiency decline and even permanent failure. The copper needle type heat sink, through the design of densely arranged needle-shaped structure, significantly increases the heat dissipation surface area and optimizes the heat convection path, and becomes a key component to solve the heat dissipation demand of IGBT high heat flux density. However, the copper base is easy to be oxidized and electrochemically corroded in long-term service, and the surface oxide film greatly increases the interface thermal resistance, and the rough surface may affect the reliability of the welding interface, therefore, the nickel plating treatment on the surface of the heat sink becomes an indispensable process link.

[0003] CN112030198A discloses a nickel plating process for inverter IGBT copper substrate, which sequentially performs chemical oil removal, electrolytic oil removal and acid activation treatment on the workpiece, and then performs electroplating treatment, uses nickel sulfate and nickel chloride for electroplating, and cooperates with a composite surfactant to improve the strength of the nickel plating layer. CN116949522A discloses an amino sulfonic acid nickel plating process for IGBT power module copper substrate, which performs pretreatment-electrolytic polishing, water washing, air knife, deoxidation and micro-etching treatment on the copper substrate, and then adopts amino sulfonic acid nickel plating, and finally performs post-treatment-closing process to improve the adhesion of the nickel plating layer.

[0004] The three-dimensional needle array structure of the pin-fin heat sink puts higher requirements on the uniformity of the nickel plating process. Non-uniform nickel plating on the heat dissipation substrate can lead to decreased heat dissipation efficiency and poor solder wettability. First, if the connection between the copper needle and the substrate is not uniform, it can cause local thermal resistance to increase. This is because the oxidation or corrosion of the thin layer can form an oxide film with low thermal conductivity, which can hinder the effective conduction of heat, thereby reducing the heat dissipation efficiency of the entire heat dissipation substrate. At the same time, the contact area between the tip of the copper needle and the cooling liquid is reduced, which reduces the heat dissipation capacity of the heat dissipation substrate. Second, uneven plating on the soldering surface of the heat dissipation substrate, i.e. uneven thickness or unevenness on the surface, can increase the surface tension between the solder and the soldered surface. The increase in surface tension can lead to an increase in wetting angle. The larger the wetting angle, the smaller the contact area between the solder and the soldered surface, which is not conducive to the spreading of the solder on the surface, resulting in poor solder wettability. Poor solder wettability can lead to uneven distribution of solder during soldering, which can easily form solder voids. These voids can hinder the effective conduction of heat, reducing the heat dissipation efficiency of the heat dissipation substrate. The presence of solder voids can reduce the actual contact area between the solder and the substrate, thereby reducing the solder strength, which can cause the solder to loosen and fall off during actual use, affecting the stability and reliability of the IGBT module.

[0005] However, the presence of small needle columns and unevenness on the surface of the pin-fin heat sink can lead to uneven distribution of the electric field, thereby affecting the uniformity of the plating layer. In addition, the gap between the copper needles is small, and the flow of the electroplating solution and the diffusion of nickel ions are limited, which can easily lead to insufficient plating of the inter-needle part, resulting in pores or thin layers or even bare copper. This makes it more difficult to achieve uniformity and stability of nickel plating on the pin-fin heat sink.

[0006] Therefore, based on this technical problem, improving the uniformity of nickel plating is the key to improving the performance of the IGBT heat sink. SUMMARY

[0007] The purpose of the present application is to provide a method for electroplating nickel on an IGBT heat dissipation substrate. By optimizing the nickel plating process, the uniformity and stability of nickel plating on the pin-fin heat dissipation substrate are improved, and the performance of the pin-fin heat dissipation substrate is guaranteed.

[0008] To achieve this purpose, the present application uses the following technical solutions:

[0009] The present application provides a method for electroplating nickel on an IGBT heat dissipation substrate, which comprises the following steps:

[0010] (1) sequentially cleaning, chemical polishing and sandblasting the heat dissipation substrate to obtain a pretreated substrate;

[0011] (2) using the pretreated substrate as the cathode and nickel as the anode to perform a pre-nickel plating treatment to obtain a pre-plated substrate;

[0012] (3) using the pre-plated substrate as a cathode and nickel as an anode to perform nickel plating treatment to obtain a nickel-plated substrate.

[0013] The method provided by the application first controls the surface roughness and topography of the heat dissipation substrate through pretreatment means of cleaning, chemical polishing and sand blasting, especially can improve the local surface state of the heat dissipation copper needle, then performs pre-nickel plating layer, realizes nickel plating activation, and then obtains a nickel layer with uniform thickness through the nickel plating process. The thickness of the obtained nickel layer is uniform at each part of the heat dissipation substrate, which guarantees the appearance and performance of the heat dissipation substrate.

[0014] Preferably, the cleaning in step (1) comprises, in sequence, ultrasonic cleaning and pickling.

[0015] Preferably, the temperature of the ultrasonic cleaning is 50-60℃, for example, can be 50℃, 52℃, 54℃, 55℃, 56℃, 58℃ or 60℃, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0016] Preferably, the time of the ultrasonic cleaning is 2-4min, for example, can be 2min, 2.5min, 3min, 3.5min or 4min, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0017] Preferably, the acid used in the pickling includes sulfuric acid.

[0018] Preferably, the mass concentration of the sulfuric acid is 10-40%, for example, can be 10%, 15%, 20%, 25%, 30%, 35% or 40%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0019] Preferably, the time of the pickling is 1-3min, for example, can be 1min, 1.5min, 2min, 2.5min or 3min, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0020] Preferably, the composition of the polishing solution used in the chemical polishing in step (1) includes acid and sulfate.

[0021] Preferably, the acid includes at least one of phosphoric acid, sulfuric acid or nitric acid.

[0022] Preferably, the sulfate includes copper sulfate and / or ammonium sulfate.

[0023] Preferably, the composition of the polishing solution used in the chemical polishing in step (1) includes, in mass fraction:

[0024] Phosphoric acid 60-70%, sulfuric acid 10-15%, nitric acid 5-10%, copper sulfate 0.5-1%, ammonium sulfate 2-5%.

[0025] The content of phosphoric acid in the polishing solution is 60-70%. For example, it can be 60%, 62%, 64%, 65%, 66%, 68%, or 70%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0026] The content of sulfuric acid in the polishing solution is 10-15%, for example, it can be 10%, 11%, 12%, 13%, 14%, or 15%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0027] The content of nitric acid in the polishing solution is 5-10%, for example, it can be 5%, 6%, 7%, 8%, 9%, or 10%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0028] The content of copper sulfate in the polishing solution is 0.5-1%, for example, it can be 0.5%, 0.6%, 0.7%, 0.8%, 0.9%, or 1%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0029] The content of ammonium sulfate in the polishing solution is 2-5%, for example, it can be 2%, 2.5%, 3%, 3.5%, 4%, 4.5%, or 5%, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0030] Preferably, the temperature of the chemical polishing is 35-55°C, for example, it can be 35°C, 40°C, 45°C, 50°C, or 55°C, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0031] Preferably, the time of the chemical polishing is 1-2 min, for example, it can be 1 min, 1.2 min, 1.5 min, 1.8 min, or 2 min, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0032] Preferably, the material of the sand particles used in the sand blasting of step (1) includes brown corundum and / or white corundum.

[0033] Preferably, the particle size of the sand particles used in the sand blasting of step (1) is 100-200 mesh, for example, it can be 100 mesh, 120 mesh, 140 mesh, 150 mesh, 160 mesh, 170 mesh, 180 mesh, 190 mesh, or 200 mesh, but is not limited to the listed values, and other values not listed in the value range are also applicable.

[0034] Preferably, the surface roughness of the substrate in step (1) is 0.9-2.5 μm, for example, it can be 0.9 μm, 1.0 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2.0 μm, 2.2 μm or 2.5 μm, but is not limited to the listed values, other values not listed in the range of values are also applicable.

[0035] Preferably, the composition of the electroplating solution in step (2) includes nickel chloride and a buffering agent.

[0036] Preferably, the concentration of the nickel chloride is 100-150 g / L, for example, it can be 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L or 150 g / L, but is not limited to the listed values, other values not listed in the range of values are also applicable.

[0037] Preferably, the buffering agent includes boric acid.

[0038] Preferably, the concentration of the boric acid is 20-60 g / L, for example, it can be 20 g / L, 30 g / L, 40 g / L, 50 g / L or 60 g / L, but is not limited to the listed values, other values not listed in the range of values are also applicable.

[0039] Preferably, the pH of the electroplating solution is 3-5, for example, it can be 3, 3.5, 4, 4.5 or 5, but is not limited to the listed values, other values not listed in the range of values are also applicable.

[0040] Preferably, the temperature of the pre-plating nickel treatment in step (2) is 60-70 °C, for example, it can be 60 °C, 62 °C, 65 °C, 68 °C or 70 °C, but is not limited to the listed values, other values not listed in the range of values are also applicable.

[0041] Preferably, the current density of the pre-plating nickel treatment in step (2) is 0.5-1 A / dm 2 , for example, it can be 0.5 A / dm 2 , 0.6 A / dm 2 , 0.7 A / dm 2 , 0.8 A / dm 2 , 0.9 A / dm 2 or 1 A / dm 2 , but is not limited to the listed values, other values not listed in the range of values are also applicable.

[0042] Preferably, the time of the pre-plating nickel treatment in step (2) is 3-5 min, for example, it can be 3 min, 3.5 min, 4 min, 4.5 min or 5 min, but is not limited to the listed values, other values not listed in the range of values are also applicable.

[0043] Preferably, the composition of the electroplating solution of the nickel plating treatment of step (3) comprises nickel sulfamate, nickel chloride and an additive.

[0044] Preferably, the concentration of the nickel sulfamate is 300-450 g / L, for example, it can be 300 g / L, 320 g / L, 350 g / L, 380 g / L, 400 g / L, 420 g / L or 450 g / L, but is not limited to the listed values, other values not listed within the value range are also applicable.

[0045] Preferably, the concentration of the nickel chloride is 30-50 g / L, for example, it can be 30 g / L, 35 g / L, 40 g / L, 45 g / L or 50 g / L, but is not limited to the listed values, other values not listed within the value range are also applicable.

[0046] Preferably, the additive comprises at least one of a buffer, a brightener or a surfactant.

[0047] Preferably, the buffer comprises boric acid.

[0048] Preferably, the concentration of the boric acid is 35-45 g / L, for example, it can be 35 g / L, 38 g / L, 40 g / L, 42 g / L or 45 g / L, but is not limited to the listed values, other values not listed within the value range are also applicable.

[0049] Preferably, the brightener comprises hexyne diol.

[0050] Preferably, the concentration of the hexyne diol is 0.5-1 g / L, for example, it can be 0.5 g / L, 0.6 g / L, 0.7 g / L, 0.8 g / L, 0.9 g / L or 1 g / L, but is not limited to the listed values, other values not listed within the value range are also applicable.

[0051] Preferably, the surfactant comprises sodium dodecylbenzenesulfonate.

[0052] Preferably, the concentration of the sodium dodecylbenzenesulfonate is 0.05-0.1 g / L, for example, it can be 0.05 g / L, 0.06 g / L, 0.07 g / L, 0.08 g / L, 0.09 g / L or 0.1 g / L, but is not limited to the listed values, other values not listed within the value range are also applicable.

[0053] Preferably, the current density of the nickel plating treatment of step (3) is 3-5 A / dm 2 , for example, it can be 3 A / dm 2 , 3.5 A / dm 2 , 4 A / dm 2, 4.5 A / dm 2 or 5 A / dm 2 but not limited to the listed values, other values within the range are also applicable.

[0054] Preferably, the time of the nickel plating treatment in step (3) is 10-25 min, for example, it can be 10 min, 12 min, 15 min, 18 min, 20 min, 22 min or 25 min, but not limited to the listed values, other values within the range are also applicable.

[0055] In the present application, the pre-nickel plating and nickel plating are carried out by wire plating.

[0056] The wire plating method specifically includes: the heat dissipation substrate workpiece is immersed in the electroplating solution for electroplating by being hung and uniformly conveyed, the distance between adjacent workpieces is 5-25 cm, the electroplating time is controlled by the moving speed of the workpiece, the workpiece is conveyed out of the plating tank, and the electroplating is ended.

[0057] Preferably, the thickness of the plating layer of the nickel plated substrate is 3-6 μm, for example, it can be 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm, 5.5 μm or 6 μm, but not limited to the listed values, other values within the range are also applicable.

[0058] Preferably, the electroplating nickel method further comprises: drying after the nickel plating treatment.

[0059] Preferably, the temperature of the drying is 70-80℃, for example, it can be 70℃, 72℃, 75℃, 78℃ or 80℃, but not limited to the listed values, other values within the range are also applicable.

[0060] Preferably, the time of the drying is 5-10 min, for example, it can be 5 min, 6 min, 7 min, 8 min, 9 min or 10 min, but not limited to the listed values, other values within the range are also applicable.

[0061] As a preferred technical scheme of the electroplating nickel method provided by the present application, the electroplating nickel method comprises the following steps:

[0062] (1) the heat dissipation substrate is first subjected to ultrasonic cleaning and pickling, the ultrasonic cleaning temperature is 50-60 DEG C, the ultrasonic cleaning time is 2-4 min, the pickling uses sulfuric acid with a mass concentration of 10-40%, the pickling time is 1-3 min; then chemical polishing is performed, the chemical polishing temperature is 35-55 DEG C, the chemical polishing time is 1-2 min, the polishing solution used in the chemical polishing comprises, by mass fraction: phosphoric acid 60-70%, sulfuric acid 10-15%, nitric acid 5-10%, copper sulfate 0.5-1%, ammonium sulfate 2-5%; sand blasting is further performed, brown corundum sand and / or white corundum sand with a particle size of 100-200 mesh are used, and a pretreated substrate with a surface roughness of 0.9-2.5 μm is obtained;

[0063] (2) the pretreated substrate is used as a cathode, and nickel is used as an anode to perform pre-plating nickel treatment, the electroplating solution used in the pre-plating nickel treatment comprises: nickel chloride 100-150 g / L, boric acid 20-60 g / L, the pH is 3-5, the pre-plating nickel treatment temperature is 60-70 DEG C, the pre-plating nickel treatment current density is 0.5-1 A / dm 2 , the pre-plating nickel treatment time is 3-5 min, and a pre-plated substrate is obtained;

[0064] (3) the pre-plated substrate is used as a cathode, and nickel is used as an anode to perform nickel plating treatment, the electroplating solution used in the nickel plating treatment comprises: nickel sulfamate 300-450 g / L, nickel chloride 30-50 g / L, boric acid 35-45 g / L, hexyne diol 0.5-1 g / L, sodium dodecyl benzene sulfonate 0.05-0.1 g / L, the nickel plating treatment current density is 3-5 A / dm 2 , the nickel plating treatment time is 10-25 min, and a nickel-plated substrate with a plating layer thickness of 3-6 μm is obtained;

[0065] (4) the surface of the nickel-plated substrate is blown dry by airflow, and dried at 70-80 DEG C for 5-10 min.

[0066] Compared with the prior art, the present application has the following beneficial effects:

[0067] The method provided by the present application improves the surface state of the heat dissipation substrate through surface pretreatment of the heat dissipation substrate, and realizes electroplating of a high-quality nickel layer on the surface of the heat dissipation substrate by combining pre-plating activation and nickel plating process, especially for pin-type heat dissipation substrates, a high-uniformity and high-bonding-force nickel-plated layer is formed on the surface, and the performance of the heat dissipation substrate is guaranteed. DETAILED DESCRIPTION

[0068] The technical solutions of the present application will be further described through specific embodiments. Those skilled in the art should understand that the embodiments are only used to help understand the present application and should not be regarded as specific limitations on the present application.

[0069] Example 1

[0070] The embodiment provides a nickel electroplating method for an IGBT pin type heat dissipation substrate, and the method comprises the following steps:

[0071] (1) ultrasonic cleaning the pin type heat dissipation substrate in hot pure water at 55 ℃ for 3 min, and then performing acid pickling on the pin type heat dissipation substrate by using a dilute sulfuric acid solution with a mass fraction of 30% for 2 min;

[0072] (2) performing chemical polishing on the pin type heat dissipation substrate after cleaning by immersing the pin type heat dissipation substrate in a polishing solution, wherein the temperature of the chemical polishing is 50 ℃, and the time of the chemical polishing is 1.5 min, and the polishing solution comprises the following components in percentage by mass: 65% of phosphoric acid, 12% of sulfuric acid, 8% of nitric acid, 0.8% of copper sulfate and 5% of ammonium sulfate;

[0073] (3) performing sand blasting treatment on the surface of the pin type heat dissipation substrate after polishing by using brown corundum with a particle size of 180 mesh, so that the roughness of the surface is controlled within the range of 0.9-2.5 μm;

[0074] (4) taking the pin type heat dissipation substrate after sand blasting treatment as a cathode, and taking nickel as an anode, and performing pre-nickel plating on the pin type heat dissipation substrate in an electroplating tank, wherein the temperature of the pre-nickel plating is 65 ℃, the current density of the pre-nickel plating is 0.8 A / dm 2 , and the time of the pre-nickel plating is 4 min, and the electroplating solution for the pre-nickel plating comprises the following components: 120 g / L of nickel chloride and 40 g / L of boric acid, and the pH value is 4;

[0075] (5) taking the pin type heat dissipation substrate after pre-nickel plating as a cathode, and taking nickel as an anode, and performing nickel plating on the pin type heat dissipation substrate in an electroplating tank, wherein the current density of the nickel plating is 4 A / dm 2 , and the total time of the nickel plating is 20 min, and the electroplating solution for the nickel plating comprises the following components: 400 g / L of nickel sulfamate, 40 g / L of nickel chloride, 40 g / L of boric acid, 0.8 g / L of 3-hexyne-2,5-diol and 0.08 g / L of active agent sodium dodecylbenzenesulfonate;

[0076] (6) blowing the pin type heat dissipation substrate after nickel plating with airflow to dry the surface, and drying the pin type heat dissipation substrate at 75 ℃ for 8 min, so as to obtain a pin type heat dissipation substrate after nickel plating.

[0077] Embodiment 2

[0078] The embodiment provides a nickel electroplating method for an IGBT pin type heat dissipation substrate, and the method comprises the following steps:

[0079] (1) ultrasonic cleaning the pin type heat dissipation substrate in hot pure water at 50 ℃ for 4 min, and then performing acid pickling on the pin type heat dissipation substrate by using a dilute sulfuric acid solution with a mass fraction of 10% for 3 min;

[0080] (2) the cleaned needle type heat dissipation substrate is immersed in a polishing solution to complete chemical polishing by etching, the temperature of the chemical polishing is 55℃, and the time is 1 minute, wherein the polishing solution comprises, in mass percentage, phosphoric acid 60%, sulfuric acid 15%, nitric acid 5%, copper sulfate 1%, and ammonium sulfate 2%;

[0081] (3) the surface of the polished needle type heat dissipation substrate is subjected to sand blasting treatment by using brown corundum with a particle size of 200 mesh, so that the surface roughness is controlled within the range of 0.9-2.5 μm;

[0082] (4) the needle type heat dissipation substrate subjected to sand blasting treatment is used as a cathode, and nickel is used as an anode to perform pre-plating of nickel in an electroplating tank, the temperature of the pre-plating of nickel is 70℃, the current density is 0.5 A / dm 2 , and the time is 5 minutes, wherein the electroplating solution for the pre-plating of nickel comprises nickel chloride 150 g / L, boric acid 20 g / L, and the pH is 5;

[0083] (5) the needle type heat dissipation substrate subjected to pre-plating of nickel is used as a cathode, and nickel is used as an anode to perform plating of nickel in an electroplating tank, the current density for the plating of nickel is 5 A / dm 2 , and the total time is 10 minutes, wherein the electroplating solution for the plating of nickel comprises nickel sulfamate 450 g / L, nickel chloride 30 g / L, boric acid 35 g / L, 3-hexyne-2,5-diol 1 g / L, and active agent sodium dodecylbenzenesulfonate 0.05 g / L;

[0084] (6) the needle type heat dissipation substrate subjected to plating of nickel is subjected to surface blowing dry by airflow, and is dried at 70℃ for 10 minutes to obtain a needle type heat dissipation substrate subjected to plating of nickel.

[0085] Example 3

[0086] The embodiment provides a nickel electroplating method for an IGBT needle type heat dissipation substrate, and the method comprises the following steps:

[0087] (1) the needle type heat dissipation substrate is subjected to ultrasonic cleaning in hot pure water at 60℃ for 2 minutes, and then is subjected to acid pickling in a dilute sulfuric acid solution with a mass fraction of 40% for 1 minute;

[0088] (2) the cleaned needle type heat dissipation substrate is immersed in a polishing solution to complete chemical polishing by etching, the temperature of the chemical polishing is 35℃, and the time is 2 minutes, wherein the polishing solution comprises, in mass percentage, phosphoric acid 70%, sulfuric acid 10%, nitric acid 10%, copper sulfate 0.5%, and ammonium sulfate 5%;

[0089] (3) the surface of the polished needle type heat dissipation substrate is subjected to sand blasting treatment by using brown corundum with a particle size of 150 mesh, so that the surface roughness is controlled within the range of 0.9-2.5 μm;

[0090] (4) The sandblasted needle-shaped heat dissipation substrate is used as the cathode and nickel is used as the anode to pre-plate nickel in an electroplating tank, the pre-plate nickel temperature is 60℃, the current density is 1A / dm 2 , and the time is 3min, wherein the pre-plate nickel electroplating solution formula comprises: nickel chloride 100g / L, boric acid 60g / L, and pH is 3;

[0091] (5) The pre-plate nickel needle-shaped heat dissipation substrate is used as the cathode and nickel is used as the anode to plate nickel in an electroplating tank, the plate nickel current density is 3A / dm 2 , and the total time is 25min, wherein the plate nickel electroplating solution formula comprises: nickel sulfamate 300g / L, nickel chloride 50g / L, boric acid 45g / L, 3-hexyne-2,5-diol 0.5g / L, and active agent sodium dodecyl benzene sulfonate 0.1g / L;

[0092] (6) The nickel-plated needle-shaped heat dissipation substrate is blown dry on the surface by airflow, dried at 80℃ for 5min, and a nickel-plated needle-shaped heat dissipation substrate is obtained.

[0093] Example 4

[0094] The embodiment provides a nickel electroplating method for an IGBT needle-shaped heat dissipation substrate, compared with example 1, the pre-plate nickel temperature in step (2) is controlled to be 55℃, and the rest are the same as those in example 1.

[0095] Example 5

[0096] The embodiment provides a nickel electroplating method for an IGBT needle-shaped heat dissipation substrate, compared with example 1, the pre-plate nickel temperature in step (2) is controlled to be 75℃, and the rest are the same as those in example 1.

[0097] Example 6

[0098] The embodiment provides a nickel electroplating method for an IGBT needle-shaped heat dissipation substrate, compared with example 1, the pre-plate nickel current density in step (2) is controlled to be 2A / dm 2 , and the rest are the same as those in example 1.

[0099] Example 7

[0100] The embodiment provides a nickel electroplating method for an IGBT needle-shaped heat dissipation substrate, compared with example 1, in step (3), no nickel chloride is added to the plate nickel electrolyte, and the rest are the same as those in example 1.

[0101] Comparative Example 1

[0102] The comparative example provides a nickel electroplating method for an IGBT needle-shaped heat dissipation substrate, compared with example 1, no step (2) chemical polishing is performed, and the rest are the same as those in example 1.

[0103] Comparative Example 2

[0104] The present comparative example provides a method for electroplating nickel on an IGBT pin-type heat dissipation substrate, which is the same as Example 1 except that step (4) of pre-plating nickel is not performed.

[0105] The nickel-plated pin-type heat dissipation substrates provided by the examples and comparative examples are respectively taken from the top of the heat dissipation pins, the bottom of the heat dissipation pins and the plane of the substrate to test the plating layer thickness and bonding strength, respectively recorded as point A, point B and point C, to illustrate the plating layer thickness and uniformity, and the results are shown in Table 1.

[0106] The specific method for testing the bonding strength is as follows: a knife is used to draw a grid (6x6mm or 11x11mm) on the surface of the plating layer, the scratches are deep into the substrate, then the grid area is adhered with adhesive tape and quickly peeled off, and the bonding strength is rated according to the proportion of the area of the plating layer adhered by the adhesive tape in the grid, with reference to the standard ASTM D3359, and the bonding strength is rated from strong to weak as 0-5 levels.

[0107] Table 1

[0108]

[0109]

[0110] As can be seen from Table 1:

[0111] The electroplating nickel method provided by the present application can realize high-quality electroplating of nickel on the surface of the heat dissipation substrate, form a uniform and high-strength nickel plating layer, and protect the performance of the heat dissipation substrate. Changing the process parameters of pre-plating nickel, such as pre-plating temperature and current density, will affect the thickness and uniformity of the nickel plating layer, and not adding nickel chloride during electroplating will significantly affect the uniformity and bonding strength of the plating layer. In the comparative example, without chemical polishing or pre-plating nickel, the thickness and uniformity of the nickel plating layer will be significantly deteriorated, and the bonding strength will be deteriorated.

[0112] In summary, the method provided by the present application improves the surface state of the heat dissipation substrate through surface pretreatment of the heat dissipation substrate, and realizes high-quality electroplating of nickel on the surface of the heat dissipation substrate by combining pre-plating activation and nickel plating process, especially for pin-type heat dissipation substrates, forming a high-uniformity and high-bonding-strength nickel plating layer on the surface, and protecting the performance of the heat dissipation substrate.

[0113] The applicant declares that the above description is only a specific embodiment of the present application, but the protection scope of the present application is not limited thereto, and those skilled in the art should understand that any changes or replacements within the technical scope disclosed by the present application can be easily thought of by those skilled in the art, and all fall within the protection scope and disclosure scope of the present application.

Claims

1. A method of electroplating nickel on an IGBT heat sink substrate, characterized by, The electroplating nickel method comprises the following steps: (1) sequentially performing cleaning, chemical polishing and sand blasting on the heat dissipation substrate to obtain a pretreated substrate; (2) performing pre-plating nickel treatment on the pretreated substrate as a cathode and nickel as an anode to obtain a pre-plated substrate; (3) performing nickel plating treatment on the pre-plated substrate as a cathode and nickel as an anode to obtain a nickel-plated substrate.

2. The electroplating nickel method according to claim 1, characterized in that, The cleaning in step (1) comprises ultrasonic cleaning and pickling in sequence; Preferably, the temperature of the ultrasonic cleaning is 50-60℃; Preferably, the time of the ultrasonic cleaning is 2-4min; Preferably, the acid used in the pickling comprises sulfuric acid; Preferably, the mass concentration of the sulfuric acid is 10-40%; Preferably, the time of the pickling is 1-3min.

3. The electroplating nickel method according to claim 1 or 2, characterized in that, The polishing solution used in the chemical polishing in step (1) comprises acid and sulfate; Preferably, the acid comprises at least one of phosphoric acid, sulfuric acid or nitric acid; Preferably, the sulfate comprises copper sulfate and / or ammonium sulfate; Preferably, the composition of the polishing solution used in the chemical polishing in step (1) comprises, in terms of mass fraction: phosphoric acid 60-70%, sulfuric acid 10-15%, nitric acid 5-10%, copper sulfate 0.5-1%, ammonium sulfate 2-5%; Preferably, the temperature of the chemical polishing is 35-55℃; Preferably, the time of the chemical polishing is 1-2min.

4. The electroplating nickel method according to any one of claims 1 to 3, characterized in that, The sand used in the sand blasting in step (1) comprises brown corundum and / or white corundum; Preferably, the particle size of the sand used in the sand blasting in step (1) is 100-200 mesh; Preferably, the surface roughness of the pretreated substrate in step (1) is 0.9-2.5μm.

5. The electroplating nickel method according to any one of claims 1 to 4, characterized in that, The electroplating solution used in the pre-plating nickel treatment in step (2) comprises nickel chloride and a buffer; Preferably, the concentration of the nickel chloride is 100-150g / L; Preferably, the buffer comprises boric acid; Preferably, the concentration of the boric acid is 20-60g / L; Preferably, the pH of the electroplating solution is 3-5.

6. The electroplating nickel method according to any one of claims 1 to 5, characterized in that, The temperature of the pre-plating nickel treatment in step (2) is 60-70℃; Preferably, the current density of the pre-nickel plating treatment of step (2) is 0.5-1 A / dm 2 ; Preferably, the time of the pre-plating nickel treatment in step (2) is 3-5min.

7. The electroplating nickel method according to any one of claims 1 to 6, characterized in that, The electroplating solution used in the nickel plating treatment in step (3) comprises nickel sulfamate, nickel chloride and an additive; Preferably, the concentration of the nickel sulfamate is 300-450g / L; Preferably, the concentration of the nickel chloride is 30-50g / L; Preferably, the additive comprises at least one of a buffer, a brightener or a surfactant; Preferably, the buffer comprises boric acid; Preferably, the concentration of the boric acid is 35-45g / L; Preferably, the brightener comprises hexyne diol; Preferably, the concentration of the hexyne diol is 0.5-1g / L; Preferably, the surfactant comprises sodium dodecyl benzene sulfonate; Preferably, the concentration of the sodium dodecyl benzene sulfonate is 0.05-0.1g / L.

8. The electroplating nickel method according to any one of claims 1 to 7, characterized in that, The current density of the nickel plating treatment of step (3) is 3-5 A / dm 2 ; Preferably, the time of the nickel plating treatment in step (3) is 10-25min; Preferably, the thickness of the plating layer of the nickel-plated substrate is 3-6μm.

9. The electroplating nickel process according to any one of claims 1 to 8, characterized in that, The electroplating nickel method further comprises drying after the nickel plating treatment. Preferably, the temperature of the drying is 70-80℃; Preferably, the time of the drying is 5-10min.

10. The electroplating nickel process according to any one of claims 1 to 9, characterized in that, The electroplating nickel method comprises the following steps: (1) The heat dissipation substrate is first subjected to ultrasonic cleaning and pickling, the temperature of the ultrasonic cleaning is 50-60℃, the time of the ultrasonic cleaning is 2-4min, the pickling uses sulfuric acid with a mass concentration of 10-40%, the pickling time is 1-3min; then chemical polishing is performed, the temperature of the chemical polishing is 35-55℃, the time of the chemical polishing is 1-2min, the polishing solution used in the chemical polishing comprises, in mass fraction: phosphoric acid 60-70%, sulfuric acid 10-15%, nitric acid 5-10%, copper sulfate 0.5-1%, ammonium sulfate 2-5%; then sand blasting is performed, brown corundum sand and / or white corundum sand with a particle size of 100-200 mesh are used, to obtain a pretreated substrate with a surface roughness of 0.9-2.5μm; (2) taking the pretreated substrate as a cathode and nickel as an anode, carrying out a pre-plating nickel treatment, the composition of an electroplating solution for the pre-plating nickel treatment comprising: 100-150 g / L of nickel chloride, 20-60 g / L of boric acid, pH being 3-5, the temperature for the pre-plating nickel treatment being 60-70 °C, the current density for the pre-plating nickel treatment being 0.5-1 A / dm 2 2, and the time for the pre-plating nickel treatment being 3-5 min, to obtain a pre-plating substrate; (3) taking the pre-plating substrate as a cathode and nickel as an anode, carrying out a nickel plating treatment, the composition of an electroplating solution for the nickel plating treatment comprising: 100-150 g / L of nickel chloride, 20-60 g / L of boric acid, pH being 3-5, the temperature for the nickel plating treatment being 60-70 °C, the current density for the nickel plating treatment being 0.5-1 A / dm 2 2, and the time for the nickel plating treatment being (3) taking the pre-plating substrate as cathode and nickel as anode, carrying out nickel plating treatment, the composition of the electroplating solution for the nickel plating treatment comprising: nickel sulfamate 300-450 g / L, nickel chloride 30-50 g / L, boric acid 35-45 g / L, hexyne diol 0.5-1 g / L, sodium dodecyl benzene sulfonate 0.05-0.1 g / L, the current density for the nickel plating treatment being 3-5 A / dm 2 , the time for the nickel plating treatment being 10-25 min, to obtain a nickel-plated substrate with a plating layer thickness of 3-6 μm; (4) The surface of the nickel-plated substrate is blown dry by airflow, and dried at 70-80℃ for 5-10min.

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