JP2014037625A - Electric plating apparatus and method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electric plating apparatus and a method of the same in which a natural oxidation layer on a plated surface is removed, and a plating step can be performed after removing the oxide layer.SOLUTION: An electric plating apparatus includes: a plating tank 110; an anode electrode 121 and a cathode electrode 122 in which an oxide layer that deposits in an electrolyte and is on a plated surface of a plating object body is removed and electrodeposition is performed on the plated surface; a capacitor 130 that is parallelly connected to a connection line of both electrodes, supplies voltage pulse between both electrodes, and removes the oxide layer on the plated surface of the object body; an apparatus 140 that is connected to both electrodes respectively, and supplies DC power for charging of the capacitor or plating of the object body; a variable resistance 150 that is parallelly connected on a line between the apparatus and the capacitor and adjusts charging and discharge of the capacitor, and current density at electrodeposition; and two or more switches that is disposed on a circuit line that connects the DC power supply feeder, the anode and cathode electrodes, and performs on/off operation for removing the oxide layer of the object body or electrodeposition.

Description

  The present invention relates to an electroplating apparatus and a method thereof, and more particularly, to an electroplating apparatus and a method thereof that can perform both removal of an oxide film on a plating surface and electroplating in a plating apparatus.

  In general, the plating means a process of coating a thin film of metal or alloy on the surface of an object to be electrolyzed. There are various methods such as decorative beautification, corrosion prevention, improved wear resistance, and improved contact resistance. It is used in the field.

  Such plating is classified in various ways according to the method and purpose, but recently, electroplating is particularly important. Usually, the term “plating” mainly means electroplating.

  First, the principle of electroplating will be briefly described. Electroplating includes metal ions to be electrodeposited with the object to be plated (electrolyte) as the cathode electrode (cathode) and the metal to be electrodeposited (metal for plating) as the anode electrode (anode). A phenomenon is used in which the metal ions are deposited on the surface of the object to be electrolyzed by putting the object to be electrolyzed and the metal for plating in an electrolytic solution and energizing both electrodes to cause ionization.

  In such electroplating, as a pretreatment process, it is necessary to remove a native oxide film that is thinly covered (about 10 nm or less) on the surface of the object to be plated. In electroplating, in order to maintain a constant current density and obtain a uniform plating thickness, it is essential to remove the oxide film present on the surface to be plated.

Korean Published Patent No. 10-2008-0046372 US Patent No. 7,507,320

  In the case of the conventional electroplating method, chemical etching is used to remove the oxide layer, or a chemical removal process such as immersing the plating object in a hydrofluoric acid (HF) solution to remove the oxide layer is performed. There must be. In addition, various chemical materials used in the plating pretreatment process are materials that are extremely toxic to the human body. For this reason, in electroplating, an environmentally friendly pretreatment process is required while reducing costs and time loss.

  The present invention has been made in view of the above-described problems, and is a natural oxide layer present on a plating surface in a state where a metal to be plated is placed in an electrolytic solution of a plating tank without a separate pretreatment process. An object of the present invention is to provide an electroplating apparatus and method thereof that can immediately remove the metal oxide, and can immediately perform the plating step after removing the oxide layer.

  In order to solve the above-mentioned object, an electroplating apparatus according to the present invention includes a plating tank filled with an electrolytic solution for electroplating, an oxide layer deposited on the electrolytic solution, supplied with power, and on the plating surface of the object to be plated. An anode electrode and a cathode electrode that perform electroplating on the plating surface and a connection line of the anode electrode and the cathode electrode are connected in parallel, and a voltage pulse is supplied between the electrodes to supply the object to be plated A capacitor that removes an oxide layer on the plating surface of the battery, and a DC power supply device that is connected to the anode electrode and the cathode electrode and supplies a DC power source for charging the capacitor or plating the object to be plated, , Connected in parallel on a power supply line between the DC power supply device and the capacitor, and the current density is adjusted during charging and discharging of the capacitor and electroplating. Variable resistance, and a circuit line connecting the DC power supply device and the anode electrode and the cathode electrode, and are turned on / off (ON / OFF) for removal of an oxide layer or electroplating of the object to be plated. OFF) and a plurality of switches that operate.

  Preferably, the electroplating apparatus according to the present invention further includes an oscilloscope for recording a voltage pulse supplied between the anode electrode, the cathode electrode, and the capacitor on the circuit line.

  The plurality of switches include a first switch provided on a circuit line between an anode terminal of the DC power supply device and the variable resistor, a cathode terminal of the capacitor, and one side end of the variable resistor. A second switch provided on the circuit line between the common connection point N and the circuit line connecting the cathode electrode and the common connection point N between the cathode terminal of the capacitor and one end of the variable resistor And a third switch provided in the configuration.

  In order to solve the above-mentioned object, an electroplating method according to another embodiment of the present invention includes an anode electrode and a cathode electrode, a capacitor, a DC power supply device, a variable resistor, and a capacitor to be charged and plated. A first switch involved in the plating of the body, a second switch involved in the charge and discharge of the capacitor and the removal of the oxide layer of the object to be plated, and the removal of the oxide layer of the object to be plated and the plating An electroplating method used in an electroplating apparatus including a third switch, wherein: a) the third switch is turned off, the first switch and the second switch are turned on, and the DC power supply is supplied Charging a charge from the device to the capacitor; and b) when charging of the capacitor is completed, the first switch is turned off, and the second and third switches are turned on. And c) discharging the charge accumulated in the capacitor; and c) continuing to discharge the capacitor, causing a thermal runaway phenomenon on the plating surface of the object to be plated as the cathode electrode, Removing the oxide layer from the surface; and d) after removing the oxide layer, turning off the second switch, turning on the first and third switches, and forming the object to be plated as the cathode electrode. Electroplating the plated surface.

  Preferably, the capacitor is charged and discharged in steps a) and b), and the electric current during charging and discharging of the capacitor and electroplating is changed by varying the resistance with the variable resistance during electroplating in step d). Adjust the density.

  Preferably, a voltage pulse supplied between the anode electrode and the cathode electrode is recorded using an oscilloscope when the capacitor is discharged in step b).

  ADVANTAGE OF THE INVENTION According to this invention, while reducing the cost and time loss in electroplating, the environmentally friendly electroplating apparatus and method which do not have a bad influence on an environmental pollution or a human body can be provided.

It is drawing which shows the structure of the conventional electroplating apparatus roughly. 1 is a drawing schematically showing a configuration of an electroplating apparatus according to an embodiment of the present invention. 3 is a flowchart illustrating an electroplating method according to an embodiment of the present invention. It is drawing which shows the result of having performed copper (Cu) plating to the steel plate using the electroplating apparatus by this invention and the general electroplating apparatus.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. Each embodiment shown below is given as an example so that those skilled in the art can sufficiently communicate the idea of the present invention. Therefore, the present invention is not limited to the embodiments described below, but can be embodied in other forms. In the drawings, the size and thickness of the device can be exaggerated for convenience. Like reference numerals refer to like elements throughout the specification.

  The terminology used herein is for the purpose of describing embodiments and is not intended to limit the invention. In this specification, the singular includes the plural unless specifically stated otherwise. As used herein, “includes” a stated component, step, action, and / or element does not exclude the presence or addition of one or more other components, steps, actions, and / or elements. Want to be understood.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

  First, in order to help understanding of the present invention, a conventional electroplating method will be briefly described.

  FIG. 1 is a drawing schematically showing a configuration of a conventional electroplating apparatus.

  As shown in FIG. 1, a conventional electroplating apparatus includes a plating tank 10 filled with an electrolyte, an anode electrode 11 and a cathode electrode 12 deposited in the electrolyte in the plating tank 10, and these A DC power supply device (DC supply) 14 for supplying power to both electrodes 11 and 12 and a switch 13 for switching power supply from the DC power supply device 14 to the anode electrode 11 and the cathode electrode 12 side. The In this case, the metal to be plated is used as the cathode. For convenience of explanation, any metal to be plated is referred to as M.

After immersing the two electrodes 11 and 12 in an electrolyte containing metal M ions, when both the electrodes 11 and 12 are connected to the DC power supply device 14, an oxidation reaction occurs at the anode electrode 11, and M ⁺ and Electrons (e ⁻ ) are created. M ⁺ becomes soluble in the electrolytic solution, and electrons (e ⁻ ) move to the cathode electrode 12 along the electric wire.

At the cathode electrode (cathode plate) 12, the collected electrons meet M ⁺ in the electrolytic solution to cause a reduction reaction, so that a solid metal M is produced and attaches to the cathode electrode (cathode plate) 12. When the reaction continues further, the entire surface of the cathode electrode (cathode plate) 12 is covered with metal, and electroplating is completed.

In relation to the series of electroplating as described above, the following items greatly affect the mechanical, physical, chemical and electrical properties of the plating layer, and are major evaluation items for electroplating.
1. 1. Uniform plating thickness over the entire plating surface 2. Uniform plating density and plating structure over the entire plating surface Strong adhesion between plating layer and plating surface

  Therefore, before performing plating, various foreign substances that may interfere with the contact between the electrolytic solution and the plating surface must be removed as a pretreatment operation. In electroplating, it is particularly important to maintain a constant current density. For this reason, the natural oxide film present on the metal surface must be removed. In the case of a metal body, since a natural oxide film is indispensably generated on the surface in the atmosphere, it is essential to remove the natural oxide film before the electroplating.

  In the case of the conventional electroplating method, mechanical etching is used to remove the oxide layer, or the oxide layer is removed by immersing the object to be plated in a hydrofluoric acid (HF) solution. Don't be. In addition, various chemical materials used in the plating pretreatment process are materials that are extremely toxic to the human body. For this reason, cost and time loss are reduced in electroplating and an environmentally friendly pretreatment process is required.

  The present invention has been made in view of the above problems, and a natural oxide layer existing on a plating surface in a state where a metal to be plated is put in an electrolytic solution of a plating tank without a separate pretreatment process. An electroplating apparatus and a method thereof are provided, in which a plating process can be performed immediately after removing the oxide layer.

  FIG. 2 is a drawing schematically showing a configuration of an electroplating apparatus according to an embodiment of the present invention.

  As shown in FIG. 2, the electroplating apparatus according to the present invention includes a plating tank 110, an anode electrode 121 and a cathode electrode 122, a capacitor 130, a DC power supply device 140, a variable resistor 150, and a plurality of switches 161-. 163.

The plating tank 110 is filled with an electrolytic solution for electroplating. Examples of the electrolytic solution include a mixture of copper sulfate (CuSO ₄ ), 5H ₂ O, sulfuric acid (H ₂ SO ₄ ), and the like at a predetermined concentration.

  The anode and cathode electrodes 121 and 122 are deposited in the electrolytic solution, supplied with power from the DC power supply device 140, and used as a plating object (cathode electrode 122, hereinafter the same reference numerals as the cathode electrode 122). Used for removing the oxide layer on the plating surface and electroplating the plating surface.

  The capacitor 130 is connected in parallel to a connection line between the anode electrode and the cathode electrodes 121 and 122, and a voltage pulse is supplied between the electrodes 121 and 122 to oxidize the plating surface of the plating object 122. Remove the layer.

  The DC power supply device 140 is connected to the anode electrode 121 and the cathode electrode 122, and supplies DC power for charging the capacitor 130 or plating the plating object 122. Examples of the DC power supply device 140 include a secondary battery.

  The variable resistor 150 is connected in parallel on a power supply line between the DC power supply device 140 and the capacitor 130, and adjusts the current density during charging, discharging, and electroplating of the capacitor 130. An example of the variable resistor 150 is a potentiometer.

  The plurality of switches 161 to 163 are provided on a circuit line that connects the DC power supply device 140 to the anode electrode and the cathode electrodes 121 and 122, and removes an oxide layer or electroplating of the plating object 122. For on / off operation.

  Preferably, an oscilloscope 170 for recording a voltage pulse supplied between the two electrodes 121 and 122 is further provided on a circuit line between the anode electrode 121 and the cathode electrode 122 and the capacitor 130. Also good.

  The plurality of switches 161 to 163 include a first switch 161 provided on a circuit line between the anode terminal (+) of the DC power supply device 140 and the variable resistor 150, and a cathode of the capacitor 130. A second switch 162 provided on a circuit line between a common connection point N between the terminal and one end of the variable resistor 150; a cathode terminal of the gap 130 and one end of the variable resistor 150; A third switch 163 provided on a circuit line connecting the common connection point N and the cathode electrode 122 is included.

  The first switch 161 is involved in charging the capacitor 130 and plating the plating object 122 (using the plating object as a cathode as described above). The second switch 162 is involved in the charge / discharge of the capacitor 130 and the removal of the oxide layer of the plating object 122. The third switch 163 is involved in the removal of the oxide layer of the plating object 122 and plating.

  Next, the electroplating method used in the electroplating apparatus of the present invention having the above configuration will be described in detail.

  FIG. 3 is a flowchart showing an execution process of the electroplating method according to the embodiment of the present invention.

  As shown in FIG. 3, the electroplating method according to the present invention includes the anode electrode 121 and the cathode electrode 122, the capacitor 130, the DC power supply device 140, the variable resistor 150, the charging of the capacitor 130, and the like. A first switch 161 involved in plating of the plating object (cathode electrode) 122; a second switch 162 involved in charging / discharging of the capacitor 130 and removal of an oxide layer of the plating object 122; and the plating object An electroplating method used in an electroplating apparatus including a third switch 163 involved in removal and plating of the oxide layer of the body 122, and firstly turning off the third switch 163, and then switching the first switch 161 and the second switch 162 are turned on to charge the capacitor 130 from the DC power supply device 140. That (step S301). Specifically, the third switch 163 is turned off (opened), the first and second switches 161 and 162 are turned on (closed), the electrodes 121 and 122 are separated from the circuit, and the DC power supply device 140 The capacitor 130 is charged with electric charge.

  Thus, when the charging of the capacitor 130 is completed, the first switch 161 is turned off, the second and third switches 162 and 163 are turned on, and the electric charge accumulated in the capacitor 130 is discharged (step). S302).

  As described above, the capacitor 130 is continuously discharged, thereby causing a thermal runaway phenomenon on the plating surface of the plating object 122 as the cathode electrode, and removing the oxide layer from the plating surface (step S303).

  Specifically, the first switch 161 is turned off (opened), the second and third switches 162 and 163 are turned on (closed), and the capacitor 130 instantaneously passes through the electrolyte in which both electrodes 121 and 122 are deposited. As a result of the electrical discharge, the electron density of the cathode electrode (plating object) 122 increases. A temporary voltage pulse between both electrodes 121, 122 is recorded by an oscilloscope 170 connected to the circuit. Thus, by recording the temporary voltage pulse with the oscilloscope 170, the electroplating operator can confirm the magnitude of the voltage pulse applied between the electrodes 121 and 122. If necessary, the oxide layer on the plating surface of the cathode electrode (plating object) 122 can be removed by adjusting the density of the current applied between the electrodes 121 and 122 even if the variable resistor 150 is adjusted. It can be done smoothly.

On the other hand, as the capacitor 130 continues to discharge, a larger amount of electrons are emitted to the cathode electrode (plating object) 122, and the electron density of the cathode electrode (plating object) 122 becomes very high. In this case, the oxide layer having a thickness of several nanometers on the plating surface of the cathode electrode (object to be plated) 122 is extremely heated by the high current density, and unlike the conductor, the temperature in such a dielectric layer (oxide layer). An increase in current causes an increase in current. This causes a chain reaction that causes an additional increase in temperature. This is called a thermal runaway phenomenon. Such a thermal runaway phenomenon sharply increases the kinetic energy of oxygen ions (O ²⁻ ) bonded to the metal surface and lowers the activation energy. At this time, oxygen molecules (O ₂ ) are separated from the metal surface and released into the atmosphere by the combination of electrons and oxygen ions (O ²⁻ ) injected into the oxide layer. Through this process, the oxide layer on the plating surface of the cathode electrode (plating object) 122 is removed.

  Thus, after the oxide layer is removed, the second switch 162 is turned off (opened), the first and third switches 161 and 163 are turned on (closed), and the cathode as the cathode electrode is turned on. The plating surface of the plating object 122 is electroplated (step S304).

  In a series of processes as described above, charging and discharging of the capacitor 130 by charging and discharging the capacitor 130 in the steps S301 and S302 and varying the resistance by the variable resistor 150 during the electroplating in the step S304. Adjust the current density during electroplating. This is to realize smooth progress of charging and discharging and uniform plating.

  Preferably, voltage pulses supplied between the anode electrode and the cathode electrodes 121 and 122 are recorded using an oscilloscope when the capacitor 130 is discharged in step S302. This is because, as described above, the temporary voltage pulse is recorded by the oscilloscope 170 so that the electroplating operator can confirm the magnitude of the voltage pulse applied between the two electrodes 121 and 122. If necessary, the variable resistor 150 is adjusted to adjust the density of the current applied between the electrodes 121 and 122, thereby removing the oxide layer on the plating surface of the cathode electrode (plating object) 122. This is so as to perform smoothly.

  FIG. 4 is a view showing a result of performing copper (Cu) plating on a steel plate using the electroplating apparatus according to the present invention and a general electroplating apparatus.

  FIG. 4 (a) shows a case where the electroplating apparatus of the present invention is used for plating after removing the oxide layer in the electrolyte before plating. FIG. 4 (b) shows the oxide layer before plating. This is a case where plating is performed using a general electroplating apparatus without going through the removal process. As shown in FIG. 3, it can be seen that when the plating is performed with a general electroplating apparatus (in the case of FIG. 4 (b)), almost no plating is performed without going through the process of removing the oxide layer before plating. In contrast, when plating is performed after removing the oxide layer in the electrolytic solution before plating using the electroplating apparatus of the present invention (in the case of FIG. 4A), copper plating is performed over the entire surface of the steel sheet. It turns out that it is performed uniformly.

  As described above, according to the electroplating apparatus and the method thereof according to the present invention, the metal to be plated is put into the electrolytic solution in the plating tank by the operation of the capacitor and the plurality of switches without a separate pretreatment process. Thus, the following advantages or effects can be obtained by immediately removing the natural oxide layer present on the plating surface and performing the plating step immediately after removing the oxide layer.

  First, before the electroplating, the removal of the surface oxide layer required as a pretreatment process can be performed immediately in the plating apparatus without a separate processing apparatus.

  Secondly, when the surface oxide layer is removed, the toxic chemical material that has been used is not used at all, so that electroplating more environmentally friendly is possible.

  Third, since the surface oxide layer is immediately removed in the plating apparatus without a separate processing apparatus, the cost of pretreatment in electroplating can be reduced.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

10, 110 Plating tank 11, 121 Anode electrode 12, 122 Cathode electrode 13 Switch 130 Capacitor 14, 140 DC power supply device 150 Variable resistor 161 First switch 162 Second switch 163 Third switch 170 Oscilloscope

Claims (6)

A plating tank filled with an electrolytic solution for electroplating;
An anode electrode and a cathode electrode that are deposited in the electrolytic solution, supplied with power, and remove the oxide layer on the plating surface of the object to be plated and perform electroplating on the plating surface;
A capacitor connected in parallel to a connection line of the anode electrode and the cathode electrode, supplying a voltage pulse between the electrodes, and removing an oxide layer on the plating surface of the object to be plated;
A DC power supply device connected to each of the anode electrode and the cathode electrode and supplying a DC power source for charging the capacitor or plating the object to be plated;
A variable resistor connected in parallel on a power supply line between the DC power supply device and the capacitor, and for adjusting the current density during charging and discharging of the capacitor and electroplating;
A plurality of switches which are provided on a circuit line connecting the DC power supply device and the anode electrode and the cathode electrode and which are turned on / off for removing an oxide layer of the object to be plated or for electroplating. Electroplating equipment.   The electroplating apparatus according to claim 1, further comprising an oscilloscope for recording a voltage pulse supplied between the anode electrode, the cathode electrode, and the capacitor on a circuit line between the electrodes. The plurality of switches are:
A first switch provided on a circuit line between the anode terminal of the DC power supply device and the variable resistor;
A second switch provided on a circuit line between a common connection point N between the cathode terminal of the capacitor and one end of the variable resistor;
The third switch provided on a circuit line that connects a common connection point N between the cathode terminal of the capacitor and one end of the variable resistor and the cathode electrode. Electroplating equipment. An anode electrode, a cathode electrode, a capacitor, a DC power supply device, a variable resistor, a first switch involved in charging of the capacitor and plating of the object to be plated, charging and discharging of the capacitor, and of the object to be plated An electroplating method used in an electroplating apparatus comprising: a second switch involved in removal of an oxide layer; and a third switch involved in removal of the oxide layer of the object to be plated and plating,
a) turning off the third switch, turning on the first switch and the second switch, and charging the capacitor from the DC power supply device;
b) when charging of the capacitor is completed, turning off the first switch, turning on the second and third switches, and discharging the charge accumulated in the capacitor;
c) causing a thermal runaway phenomenon on the plating surface of the object to be plated as the cathode electrode by continuing to discharge the capacitor, and removing the oxide layer from the plating surface;
d) after removing the oxide layer, turning off the second switch, turning on the first and third switches, and electroplating the plating surface of the object to be plated as the cathode electrode. Electroplating method.   During charging and discharging of the capacitor in steps a) and b) and in electroplating in step d), the current density during charging and discharging of the capacitor and electroplating is adjusted by varying the resistance by the variable resistance. The electroplating method according to claim 4.   5. The electroplating method according to claim 4, wherein a voltage pulse supplied between the anode electrode and the cathode electrode is recorded using an oscilloscope when the capacitor is discharged in the step b).

Images