JP5394012B2 - Electronic component plating equipment - Google Patents

Description

  The present invention relates to an electronic component plating apparatus for plating a long substrate having an electronic component element formed and a metal film formed on a side surface. For example, an electronic device capable of plating an electrode or the like of a chip-type electronic component. The present invention relates to a component plating apparatus.

  Small electronic components such as chip resistors, chip capacitors, and chip inductors are used as external electrodes for soldering on circuit boards to improve soldering performance and ensure electrical continuity. It is plated.

Conventionally, a barrel method (barrel plating method) is generally used for an apparatus for plating these external electrodes (see, for example, Patent Document 1). The barrel method is a method in which small electronic components divided into chips are put into a cylindrical barrel together with dummy balls, and electroplating is performed on the small electronic components while rotating the barrel in a plating tank filled with a plating solution. is there.
On the other hand, for example, a technique described in Patent Document 2 is known as an apparatus for manufacturing a wiring substrate by plating a strip-like flexible long substrate.

JP 2000-260611 A Japanese Patent Laid-Open No. 2003-321796

  In the barrel method described above, a large number of small electronic components can be plated at a time. However, there is a possibility that the small electronic components may overlap each other, and it is inevitable that defective products are generated as a result of the overlapping.

  In addition, since a large number of dummy balls are required as a current-carrying medium, there is a problem that the equipment is enlarged, energy consumption for rotating the barrel is large, and waste liquid is also large.

  Furthermore, plating also adheres to the dummy balls, and the dummy balls that are out of the standard size due to the adhesion of the plating are discarded, so that there is a problem that the corresponding plating material is wasted.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to provide a plating apparatus for an electronic component capable of performing plating with a small variation in plating thickness by a small apparatus that does not use dummy balls. That is.

  As a means for achieving this object and solving the above-mentioned problems, for example, the following configuration is provided. That is, an electronic component plating apparatus for plating a long substrate having an electronic component element formed thereon and a metal film formed on a side surface, the plating tank having an electrode disposed therein, and the length of the plating tank A first contact electrode disposed in the vicinity of the long substrate carry-in port and capable of contacting the metal film; and a second contact electrode disposed in the vicinity of the long substrate carry-out port of the plating tank and capable of contacting the metal film. A power source capable of applying a positive potential to the electrode in the plating tank and a negative potential to the first contact electrode and the second contact electrode, and the metal film as the first contact electrode. Transporting means for transporting the long substrate into the plating tank while being in contact with the metal plate, and transporting the metal film to the outside of the plating tank while being in contact with the second contact electrode. Supply current to the contact electrode of the second contact And supplying to be larger than the supply current to the electrodes.

  And, for example, the transport means allows the plurality of long substrates to pass through the plating tank continuously in a tandem state while the metal film is in contact with the first contact electrode and the second contact electrode. To do.

  Further, for example, the first contact electrode and the second contact electrode are each composed of a pair of electrodes that are spaced apart from each other by a predetermined distance, and the transfer means includes the metal films on both sides of the long substrate between the contact electrodes. It conveys in the state which contacted.

  Further, for example, two electrodes in the plating tank are provided so as to sandwich the long substrate, and the power source is divided into two systems so as to correspond to the respective metal films on both side surfaces of the long substrate. It is provided for each side.

  Further, for example, the long substrate is a strip-shaped substrate before the electronic component is divided into chips. Alternatively, the long substrate is a ceramic substrate.

  According to the present invention, there is provided an electronic component plating apparatus capable of suppressing plating film thickness variation between continuous long substrates and efficiently performing a plating process on an electronic component with a small apparatus. Can do.

  Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings. First, a manufacturing method of a chip-type electronic component (also referred to as a long substrate) as a plating target in the plating apparatus according to the present embodiment will be described with reference to FIGS. 1 to 8 are diagrams for explaining a method of manufacturing a chip-type electronic component (long substrate) that is a plating target in a plating apparatus according to an embodiment of the present invention.

First, a large flat substrate is prepared as a substrate for the chip-type electronic component shown in FIG. FIG. 1 shows an example of a large flat substrate 10 for electrode formation and resistor printing described later. For example, a glass material made of aluminum oxide (Al ₂ O ₃ ), silicon dioxide (SiO ₂ ), or the like. A glass-ceramic substrate (ceramic substrate) having a predetermined thickness.

  Subsequently, a primary break groove 11 and a secondary break groove 13 are formed on the front and back surfaces of the flat substrate 10 shown in FIG. FIG. 2 shows an example of a substrate on which a primary break groove 11 and a secondary break groove 13 are formed.

Next, electrodes are formed on the front and back surfaces of the flat substrate 10 on which the break grooves 11 and 13 are formed. FIG. 3 shows a state in which the electrodes are formed on the surface and the back surface of the flat substrate 10 in an orderly and regular manner, and the surface electrode 15 is formed on the surface of the flat substrate 10. FIG. 4 shows a state where an electrode (back electrode) 17 is formed on the back surface of the flat substrate 10.
In the present embodiment, for example, a silver electrode material containing glass frit is printed on the flat substrate 10 in a pattern as shown in FIGS. 3 and 4, for example, and then fired to form a front electrode and a back electrode.

  Next, a resistor 21 made of a predetermined component (for example, ruthenium oxide) is screen-printed between the surface electrodes 15 shown in FIG. 3, and then fired. FIG. 5 shows a state where the resistor 21 is screen-printed and fired.

  Next, a protective film (glass protective coat) having a function also as an insulating film is printed by, for example, screen printing or the like so as to cover these fired resistors 21 and then fired.

  Thereafter, for example, the pattern of the resistor 21 is cut by laser trimming, and resistance value trimming (resistance value adjustment) is performed. Specifically, the resistance value of the resistor 21 is measured between two electrodes at both ends thereof, and the resistor 21 is trimmed by cutting the resistor 21 with a laser or the like based on the measured value. Adjustment is made so that a resistor having a desired resistance value is obtained.

  Next, a protective film (glass protective coat) is formed, and a protective film 23 made of, for example, an epoxy resin that functions as an insulating film is formed on the resistor whose resistance value is adjusted. FIG. 6 shows a state where the protective film 23 is formed.

  Next, a primary break is performed with the break groove 11 described above as a dividing line, and the substrate 10 is broken (divided) into strips. FIG. 7 shows a state in which the substrate 10 is broken (divided) into strips. The divided strip-shaped substrate is called a long substrate.

  In the chip-type electronic component, it is necessary to electrically connect the front surface electrode and the back surface electrode. Therefore, an external electrode (side electrode) is formed on the side surface in order to electrically connect the front surface electrode and the back surface electrode of the substrate.

  In order to form an electrode on the side surface, for example, a fracture surface (both side surfaces) of a long substrate is exposed, and a conductive metal, for example, nickel-chromium (Ni / Cr) thin film 27 is formed on both side surfaces by, for example, sputtering. Form. FIG. 8 shows a state in which side electrodes are formed on this long substrate.

In this way, a long substrate having the electrode 27 formed on the side surface before the plating (electrolytic plating) is performed by the plating apparatus of the present embodiment is manufactured.
Next, a description will be given of an electronic component plating apparatus according to the present embodiment for plating the electrode surface of the long substrate thus manufactured.

  Hereinafter, the electronic device plating apparatus and the plating process according to the present embodiment will be described in detail with reference to FIG. FIG. 9 is a diagram schematically showing the overall configuration of the plating apparatus according to the present embodiment. FIG. 9A is a plan view of the plating apparatus according to the present embodiment. (B) is a side view of the plating apparatus according to the present embodiment.

  In the plating apparatus 30 of this embodiment, a plurality of plating tanks 34, 36 and cleaning tanks 33, 35, 37 are alternately arranged in tandem, and the long substrates to be plated are arranged in tandem in the tanks sequentially. It is equipped with a configuration that allows continuous plating treatment by continuously loading and conveying in a state and passing it through.

  In FIG. 9, reference numeral 31 denotes a long substrate extrusion mechanism for extruding a long substrate to be plated to the plating apparatus 30 side, and includes an extruding portion 32 that reciprocates in the longitudinal direction. When starting the plating, the extruding part 32 moves backward to the position indicated by the chain line on the left end side in FIG. In this state, one of the long substrates 28 before plating, which is placed at a predetermined position, is transported and positioned at the position of the extruding unit 32 (the position indicated by the solid line in the drawing) before the retreat.

  A pair of rollers is provided on the inlet side and the outlet side of the plating tanks 34 and 36, respectively. Specifically, rollers R1 and R2 are disposed on the inlet side of the plating tank 34, rollers R3 and R4 are disposed on the outlet side, rollers R5 and R6 are disposed on the inlet side of the plating tank 36, and rollers are disposed on the outlet side. R7 and R8 are provided.

  These rollers are made of a conductive material, and are in contact with the side electrodes of the long substrate to support and assist the loading and unloading of the long substrate to and from the plating tank. It has a function as a contact electrode for applying a predetermined voltage (negative voltage) to the side electrode of the substrate.

  After positioning the long substrate to be plated at a predetermined position, the extruded portion 32 moves from the position indicated by the chain line to the position indicated by the solid line, whereby the positioned long substrate is pushed out toward the cleaning tank 33, and the tip The portion passes through the cleaning tank 33 and moves between the rollers R1 and R2.

  The cleaning tank 33 stores an acid (for example, sulfuric acid) or water for removing impurities adhering to the surface of the long substrate. It is configured to wash and wash off the attached dirt. What is necessary is just to select the optimal thing for the washing | cleaning liquid in the washing tank 33 suitably according to the specification of pre-processing. In addition, when the surface state of the long board | substrate to be plated is a state where it is a clean state, or when it is a state which does not produce a plating defect, you may make it the structure which does not provide the washing tank 33. FIG.

  The leading end portion passes through the cleaning tank 33 and moves between the rollers R1 and R2. Thereafter, the substrates S4 to S1 are sequentially pushed by the long substrate extruded by the extrusion mechanism 31 to be conveyed in the plating process. The rollers (R1, R2, etc.) may be driven by a motor or the like so that the long substrate is conveyed by the rotation of the rollers.

  When the extrusion mechanism 31 transports the long substrate 28 between the rollers R1 and R2, it returns to the chain line position at the left end of FIG. 9 again, and a new long substrate to be plated next is transported and positioned at the 32 chain line position. Come.

  At this time, that is, it is desirable to stop the supply of the plating current from the power source until the extruding unit 32 moves backward, a new long substrate is positioned, and the extrusion of the long substrate is started. By doing in this way, the variation in the plating thickness to the elongate board | substrate in a plating tank can be suppressed.

  And a new elongate board | substrate is sent to the washing tank 33 side by the extrusion part 32. FIG. In this way, new long substrates are sequentially pushed out of the cleaning tank 33 to the rollers R1 and R2.

  The long substrate that has passed through the cleaning tank 33 is conveyed between the rollers R3 and R4 through the nickel (Ni) plating tank 34 as the rollers R1 and R2 rotate. The nickel plating tank 34 is a plating tank whose upper surface is open, and stores a plating solution containing nickel which is a metal to be plated.

  In addition, a pair of anode electrodes (anodes) 41a and 41b arranged at a predetermined interval are immersed in the vicinity of both side surfaces corresponding to the side surfaces of the long substrate in the nickel plating layer 34.

  The anode electrodes (anodes) 41a and 41b are connected to the plus side of a power source described later. By connecting the negative side of the power source, which will be described later, to rollers R1, R2, R3, and R4, it is electrically connected to anode electrodes (anodes) 41a and 41b and rollers R1, R2, R3, and R4 as cathodes (cathodes). A potential difference is generated between the side electrode of the long substrate 28 and the electrode of the long substrate passing between the anode electrodes 41a and 41b is subjected to electrolytic plating (nickel plating).

  The long substrate that has passed through the nickel plating tank 34 is pushed by the subsequent long substrate, and is transferred into the cleaning tank 35 in which a cleaning liquid such as water is stored. In the cleaning tank 35, the remaining plating solution and the like are removed from the nickel-plated long substrate.

  Next, when the long substrate from which the plating solution has been removed in the cleaning tank 35 is conveyed between the rollers R5 and R6, it is pushed by the subsequent long substrate and further in the tin (Sn) plating tank 36. Then, it is conveyed between the rollers R7 and R8 and passes through the tin plating tank 36 (see the substrates S2 and S1 in FIG. 9).

  Similar to the nickel plating tank 34, the tin plating tank 36 is a plating tank having an open upper surface, and stores a plating solution containing tin which is a metal to be plated. Similarly to the nickel plating tank 34, a pair of anode electrodes (anodes) 43 a and 43 b that are connected to the positive side of the power source and spaced apart from each other are immersed in the tin plating solution in the tank facing each other. Has been.

  Rollers R5 and R6, at least the surface of which is formed of a conductive material, are disposed near the entrance side of the tin plating tank 36, and rollers R7 and R8 are disposed on the exit side, and these rollers are disposed on the negative side of the power source. By connecting, a potential difference is generated between the long substrate electrodes contacting the rollers R5, R6, R7, and R8 that function as cathodes (cathodes) and are transported between the anode electrodes (anodes) 43a and 43b. Electrolytic plating can be applied to the electrodes on the surface of the long substrate.

  The long substrate that has passed through the tin plating tank 36 reaches the rollers R7 and R8, and is then sent to the cleaning tank 37 in which a cleaning liquid such as water is stored (see the substrate S1 in FIG. 9). This washing tank 37 is for removing the remaining plating solution from the long substrate subjected to tin plating. Thereafter, the long substrate goes through a drying process (not shown) and proceeds to a secondary breaking process.

  In addition, recovery tanks 38 and 39 for recovering the plating solution overflowing from the plating tank are disposed below the nickel plating tank 34 and the tin plating tank 36, respectively. A plating solution circulation mechanism (not shown) is provided to control so as to be reduced to the plating tanks 34 and 36.

  Next, a detailed configuration of the plating current adjusting unit in the plating tank in the plating apparatus according to the present embodiment will be described with reference to FIG. FIG. 10 is a diagram for explaining the details of the plating current adjusting section of the plating apparatus of this embodiment.

  In the following description, the nickel plating tank 34 will be described as an example, but the tin plating tank 36 has the same configuration, and the plating current is controlled in the same manner. In FIG. 10, the same components as those shown in FIG. 9 are denoted by the same reference numerals.

  A pair of anode electrodes (anodes) 41a and 41b are immersed in the nickel plating solution stored in the nickel plating tank 34. The anode electrode 41a has a positive potential of the power source A51 and the anode electrode 41b has a power source B53. Each positive potential is applied.

  Further, a negative potential of the power source A51 is applied to the roller R1, and a negative potential of the power source B53 is applied to the roller R2. The roller R3 is connected to the negative potential side of the power source A51 via a resistor 55 for current balancing, and similarly the roller R4 is connected to the negative potential side of the power source B53 via a resistor 57.

  Here, a case where no resistor is interposed between the rollers R1, R2, R3, and R4, that is, a case where the plating process is performed without taking a current balance will be described.

  For example, as shown in FIG. 11A, when the long substrate Sa is conveyed into the plating tank 34 while being sandwiched between the rollers R1 and R2, the surface electrode of the long substrate is in contact with the surface electrode. By energization from the rollers R1 and R2, a portion (side electrode portion) of the long substrate Sa that has entered the plating tank 34 is plated.

  The long substrate Sa is pushed out toward the outlet of the plating tank by the long substrate Sb following the long substrate Sa, and the long substrate Sb has entered the plating tank 34 as shown in FIG. In the state, the plating formation on the long substrate Sb has not progressed so much. Therefore, the resistance value of the side metal film is high, and it is difficult to be plated.

  On the other hand, since the long substrate Sa has already been plated, the resistance value of the side surface metal film is low, and it is easy to be plated. This is because the long substrate Sb is introduced into the nickel plating tank 34 after the long substrate Sa, so that the current balance between the rollers R1 and R2 on the inlet side and the rollers R3 and R4 on the outlet side of the nickel plating tank. This means that the plating process progresses due to the dislocation and the load on the long substrate Sa.

  Therefore, in the distribution of the plating thickness of the long substrate Sa, the plating on the rear end side is thicker than the side (front end) of the substrate that has been put into the plating tank first. In addition, there arises a problem that the left and right film thickness also varies.

  Therefore, in the plating apparatus of the present embodiment, as shown in FIG. 10, resistors 55 and 57 are provided between the negative power sources of the power sources A51 and B53 and the rollers R3 and R4 on the outlet side of the nickel plating tank. So that the current (referred to as Ia) to the rollers R1 and R2 on the inlet side of the nickel plating tank 34 becomes larger than the current (referred to as Ib) to the rollers R3 and R4 on the outlet side. Is controlling.

  In this way, the plating current supplied to the object to be plated is controlled to be (Ia> Ib), and the plating current between the long substrate electrode and the anode electrode on the inlet side and the outlet side has substantially the same current value. In this way, by setting the resistance value to an appropriate value, it is possible to balance the current and suppress variations in the plating film thickness that occurs between the long substrates Sa and Sb.

  Furthermore, as shown in FIG. 10, the power supply system is divided for the left and right side surface metal films of the long substrates Sa and Sb to be plated (independent power supplies are provided), so that the plating current between the electrodes is increased. It is possible to eliminate the variation in the thickness of the plating film as the side electrode film of the long substrate passing through the plating tank. This resistance value may be selected by experiment or may be configured to control the resistance value so that a plating current flowing between electrodes (not shown) is measured to obtain a desired current value.

  The long substrate plated by the above process becomes a chip-like electronic component that is then separated by the secondary break process. FIG. 12 shows a cross-sectional configuration of a chip-shaped electronic component (resistor in the example described above) separated by the secondary breaking process.

  In FIG. 12, a base 61 is a ceramic substrate portion obtained by dividing the planar substrate 10. The upper electrode (surface electrode) 15 shown in FIG. 3 is formed at both ends of the surface (upper surface) of the substrate 61. Similarly, a lower electrode (back surface electrode) 17 shown in FIG. 4 is formed at the end of the back surface (lower surface) of the substrate.

  A resistor 21 shown in FIG. 5 is formed by screen printing or the like between the upper electrodes 15 on the surface of the base 61 and fired to form a resistance layer. The resistor layer 21 and the upper electrode 15 are in an electrically connected state.

  The resistor (resistive layer) 21 is covered with a glass coat 63, and a protective film 23 shown in FIG. 6 that functions as an insulating film is formed thereon. In order to electrically connect the upper electrode 15 and the lower electrode 17 to each end side surface of the base 61, a nickel-chromium (Ni-Cr) film 27 as an end electrode shown in FIG. For example, it is formed by sputtering.

  Furthermore, a nickel plating layer 67 plated by the plating apparatus of this embodiment so as to cover the upper electrode 71, the lower electrode 72, and the end electrode (Ni—Cr film) 27, and a tin plating layer 68 on the nickel plating layer 67, respectively. Is formed.

  As described above, when a long substrate broken into strips is continuously put into a plating tank in a tandem state, the current to the inlet side roller of the plating tank is larger than the current to the outlet side roller. Thus, by balancing the plating current supplied to the rollers between the inlet side and the outlet side rollers, it is possible to suppress variations in the plating film thickness that occurs between continuous long substrates. At the same time, since no dummy ball is required, the apparatus can be reduced in size and energy can be saved.

  In addition, the portion to be plated to be plated is specified, that is, in the above embodiment, only the side electrode portion of the long substrate can be plated. Can be reduced.

In the embodiment described above, a resistor is used for current adjustment. However, the present invention is not limited to this, and an element other than a resistor may be used as long as the same purpose can be achieved.
In the above example, the power supply system is divided for each of the left and right side surface metal films of the long substrate. However, the present invention is not limited to this. As long as the relationship> Ib is satisfied, for example, four power supplies may be provided for each roller (four systems) to adjust the plating current to each roller.

  On the other hand, a controller capable of controlling a current system from a single power source may be prepared to adjust the plating current from the single power source to each roller. Further, the object to be plated is not limited to a chip-type resistor, and can be applied to an electronic component having an electrode terminal such as a chip-type inductor, a chip-type capacitor, a composite component thereof, a multiple resistor, or the like.

  As described above, according to the present embodiment, when the long substrates Sa and Sb broken in a strip shape are continuously put into the plating tank 34 in a column state, the plating current is supplied to one electrode. By making the current to the inlet side rollers R1, R2 of the tank 34 larger than the current to the rollers R3, R4 on the outlet side, the current of the inlet side electrode of the long substrate to the plating tank is changed to the outlet side of the long substrate. By making the current larger than the current of the electrode and balancing the current between the electrodes on the inlet side and the outlet side, the plating current variation between the surface electrode and the anode electrode of the continuous long substrates Sa and Sb is eliminated. It becomes possible to suppress variation in thickness. It is possible to efficiently perform the plating process on the electronic component with a small device.

The figure which shows the example of the large-sized plane board | substrate for performing the electrode formation of the chip-type electronic component (elongate board | substrate) which is the object of plating in the plating apparatus which concerns on the example of embodiment of 1 invention which concerns on this invention, and printing of a resistor. It is. It is a figure which shows the example of the plane board | substrate which formed the groove | channel for primary breaks, and the groove | channel for secondary breaks on the surface and the back surface of this embodiment, respectively. It is a figure which shows the example of a state which formed the surface electrode in the plane board | substrate of this Embodiment. It is a figure which shows the example of a state in which the back surface electrode was formed in the plane substrate of this Embodiment.

It is a figure which shows the state which formed the resistor between the surface electrodes of the plane board | substrate of the example of this Embodiment. It is a figure which shows the state which formed the protective film on the resistor upper part of the surface of the plane board | substrate of this Embodiment. It is a figure which shows the state which fractured | ruptured (divided) the planar substrate of the example of this Embodiment in strip shape. It is a figure which shows the state which formed the side surface electrode in the elongate board | substrate of the example of this Embodiment. It is a figure which shows typically the whole structure of the plating apparatus which concerns on the example of this Embodiment.

It is a figure which shows the adjustment structure of the plating current in the plating tank of the plating apparatus which concerns on this Example. It is a figure for demonstrating the plating process which does not take an electric current balance. It is a figure which shows the cross-sectional structure of the chip-shaped electronic component which separated the long board | substrate plated with the apparatus which concerns on the example of this embodiment by the secondary break process.

Explanation of symbols

R1 to R8 Roller 10 Flat substrate 11, 13 Break groove 15 Surface electrode (upper electrode)
17 Back electrode (lower electrode)
DESCRIPTION OF SYMBOLS 21 Resistor layer 23 Protective film 25, 28, S1-S4, Sa, Sb Long board 27 Nickel-chromium film 30 Plating apparatus 31 Extrusion mechanism of long board 32 Extrusion part 33, 35, 37 Cleaning tank 34 Nickel plating tank 36 Tin plating tank 38, 39 Recovery tank 41a, 41b, 43a, 43b Anode (anode) electrode 51 Power source A
53 Power supply B
55, 57 Resistor 61 Base 63 Glass coat 67 Nickel plating layer 68 Tin plating layer

Claims (6)

An electronic component plating apparatus that performs plating on a long substrate in which an electronic component element is formed and a metal film is formed on a side surface,
A plating tank in which electrodes are arranged;
A first contact electrode disposed in the vicinity of the elongate substrate carry-in port of the plating tank and capable of contacting the metal film;
A second contact electrode disposed in the vicinity of the long substrate carry-out port of the plating tank and capable of contacting the metal film;
A power source capable of applying a positive potential to the electrodes in the plating tank and applying a negative potential to the first contact electrode and the second contact electrode;
Conveying means for conveying the elongated substrate into the plating tank while bringing the metal film into contact with the first contact electrode, and conveying the metal film to the outside of the plating tank while being in contact with the second contact electrode; With
2. The electronic component plating apparatus according to claim 1, wherein the power source supplies the power so that a supply current to the first contact electrode is larger than a supply current to the second contact electrode. The said conveyance means passes a plurality of said elongate board | substrates through the said plating tank continuously in a column state, making the said metal film contact the 1st contact electrode and the 2nd contact electrode. The electronic component plating apparatus according to 1. The first contact electrode and the second contact electrode are each composed of a pair of electrodes separated by a predetermined distance,
2. The electronic component plating apparatus according to claim 1, wherein the transport unit transports between the contact electrodes in a state where the metal films on both side surfaces of the long substrate are in contact with each other. Two electrodes in the plating tank are provided so as to sandwich the long substrate,
4. The electronic component plating apparatus according to claim 3, wherein the power supply is provided for each side face in two systems so as to correspond to the metal films on both side faces of the long substrate. 5. The electronic component plating apparatus according to claim 1, wherein the long substrate is a strip-shaped substrate before the electronic component is divided into chips. 6. The electronic component plating apparatus according to claim 5, wherein the long substrate is a ceramic substrate.

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