JP5338084B2 - Capacitor inspection device and inspection method using the same - Google Patents

Description

  The present invention is a chip-type solid electrolytic capacitor having a four-terminal structure in which capacitors are used in various electronic devices, and in particular, the anode terminal and the cathode terminal are exposed at two locations opposite to each other on the lower surface serving as a mounting surface. The present invention relates to a capacitor inspection apparatus suitable for inspecting various characteristics such as an equivalent series inductance of a capacitor, and an inspection method using the same.

  Along with the increase in frequency of electronic equipment, capacitors that are one of the electronic components have been required to have better impedance characteristics in the high frequency range than before. Various solid electrolytic capacitors using a highly conductive polymer as a solid electrolyte have been studied.

  In recent years, a solid electrolytic capacitor used around a CPU of a personal computer has been strongly demanded to be small in size and large in capacity. Further, in addition to low ESR (equivalent series resistance) corresponding to high frequency, There is a strong demand for low ESL (equivalent series inductance) excellent in noise removal and transient response, and various studies have been made to meet such a demand.

  FIGS. 10A to 10E are plan sectional views showing the structure of a chip-type solid electrolytic capacitor having a four-terminal structure, in which a surface is mounted by arranging terminals on the lower surface among these types of solid electrolytic capacitors. It is a figure, front sectional view, side sectional view, bottom sectional view, and bottom view.

  In FIG. 10, reference numeral 40 denotes a capacitor element. The capacitor element 40 is provided with an insulating portion (not shown) at a predetermined position of an anode body made of a valve metal having a roughened surface and a dielectric oxide film layer formed thereon. Are separated into an anode electrode portion 41 and a cathode forming portion (not shown), and a solid electrolyte layer made of a conductive polymer, a cathode layer made of a carbon layer and a silver paste layer on the dielectric oxide film layer of the cathode forming portion. The cathode electrode portion 42 is formed by sequentially laminating (all not shown).

  43 is an element laminate in which a plurality of the capacitor elements 40 are laminated, and the element laminate 43 is laminated in such a manner that the anode electrode portions 41 of the capacitor elements 40 are alternately arranged in opposite directions. It is comprised by.

  44 is an anode comb frame integrally joined with the anode electrode portion 41 of the element laminate 43, and 45 is a cathode comb frame integrally joined with the cathode electrode portion 42 of the element laminate 43.

  46 is an anode terminal in which the anode comb frame 44 is joined to the upper surface. The anode terminal 46 is provided with a step portion 46b formed by bending both ends in the width direction, and a central portion excluding the step portion 46b is mounted. It becomes the anode terminal part 46a at the time. Reference numeral 46c denotes a bent portion obtained by extending a part of the anode terminal 46 so as to protrude from an exterior resin, which will be described later, in a top view, and bending the extended portion upward along the side surface of the exterior resin.

  47 is a cathode terminal obtained by bonding the cathode comb frame 45 to the upper surface. The cathode terminal 47 is provided with a thin portion 47b at the center in the width direction, and both end portions excluding the thin portion 47b are cathode terminal portions when mounted. 47a. Reference numeral 47c denotes a bent portion obtained by extending a part of the cathode terminal 47 so as to protrude from an exterior resin to be described later when viewed from the top, and bending the extended portion upward along the side surface of the exterior resin.

  Reference numeral 48 denotes an insulating exterior resin integrally covering the element laminate 43, the anode comb frame 44, the cathode comb frame 45, the anode terminal 46, and the cathode terminal 47. The step 46b provided on the anode terminal 46, the cathode The thin-walled portion 47b provided on the terminal 47 is also integrally covered with the exterior resin 48, and the anode terminal portion 46a and the cathode terminal portion 47a are exposed to the two opposing surfaces on the lower surface, which is the mounting surface of the chip-type solid electrolytic capacitor. This constitutes a 4-terminal structure.

  The thus configured chip-type solid electrolytic capacitor has a four-terminal structure in which the anode terminal portion 46a and the cathode terminal portion 47a are exposed on the lower surface serving as the mounting surface, and flows between the terminals. The magnetic flux generated by the current cancels each other, the ESL can be greatly reduced, and the distance between each terminal is made as close as possible to reduce the current loop area, further reducing the ESL. It is possible to plan (Patent Document 1).

  The chip-type solid electrolytic capacitor configured in this way is used for applications such as power supply circuits and digital circuits that require low impedance characteristics particularly in the high-frequency region, so that impedance measurement with higher accuracy is possible. For the purpose of performing the measurement, it has been proposed to measure the impedance using the following measuring device.

  FIG. 11 is a conceptual diagram showing such a conventional solid electrolytic capacitor impedance measuring apparatus. In FIG. 11, a portion 50 surrounded by a dotted line is a simplified impedance measuring instrument, 51 is an AC power source, 52 is a current limiting resistor, 53 is a current detector for detecting the current flowing through the capacitor 54, and 55 is a voltage detector, which is configured to include current terminals 56 and 57 and voltage terminals 58 and 59.

  Reference numerals 60 and 61 denote current contacts when the impedance is measured by making contact with the electrode terminal of the capacitor 54, and 62 and 63 are voltage contacts when the impedance is measured by making contact with the electrode of the capacitor 54. is there. In addition, a resistor 65 is interposed between the current contact 60 and the other end 64, and a detection resistor is connected between the voltage contact 62 and the other end 66 between the other end 64 and the other end 66 via a resistor 67. 68 is connected.

  Similarly, the other current contact 61 and the voltage contact 63 are provided with a resistor 70 between the current contact 61 and the other end 69, and a resistor 72 is also provided between the voltage contact 63 and the other end 71. A detection resistor 73 is connected between the other end 69 and the other end 71. The detection resistors 68 and 73 preferably have a value (10Ω to 100Ω) sufficiently larger than the contact resistance of the measuring contact, but the detection resistors may be omitted.

  FIG. 12 is an electrical equivalent circuit diagram of the impedance measuring apparatus shown in FIG. 11. In FIG. 12, a portion 50 surrounded by a dotted line is a simplified impedance measuring instrument, 54 is a capacitor, and is equivalent in series to a capacitance 54a. Resistor 54b is present. Further, a specific resistance 65a and a dielectric component 74 exist between the current contact 60 and the other end 64 via the resistor 65, and similarly, a specific resistance exists between the current contact 61 and the other end 69 via the resistor 70. Resistor 70a and inductive component 75 are present. Further, a specific resistance 67 a and an inductive component 76 exist between the voltage contact 62 and the other end 66 via the resistor 67, and a specific resistance 72 a exists between the voltage contact 63 and the other end 71 via the resistor 72. Inductive component 77 is present.

  In this state, the impedance of the capacitor 54 is measured by performing open correction and short circuit correction without placing the capacitor 54, and then connecting the current contacts 60 and 61 and the voltage contacts 62 and 63 to the electrode terminals at both ends of the capacitor 54. The voltage contacts 62 and 63 detect that a current flows through the current contacts 60 and 61 and a voltage is generated at both ends of the capacitor 54. The current (I) and voltage (V) at this time are detected by the voltage detector 55 and the current detector 53, and the impedance is obtained from the calculation formula of Z = V / I.

Here, since the current contacts 60 and 61 and the voltage contacts 62 and 63 are in contact with the electrode terminals of the capacitor 54, the specific resistances 65a, 70a, 67a, 72a and the inductive component 74 existing in the respective measurement contacts, 75, 76, and 77 were corrected to 0 (zero) on the electrical equivalent circuit, and the impedance could be accurately measured without any problem (Patent Document 2).
JP 2007-5760 A JP 2001-35759 A

  However, since the conventional impedance measuring apparatus for a solid electrolytic capacitor is intended to measure the impedance of the capacitor 54, which is the object to be measured, in an extremely short time online, this measurement result is used. Although it is possible to obtain the ESL of the capacitor, there is a problem that the measurement accuracy is poor and a high-precision inspection device is required to measure a solid electrolytic capacitor for which a low ESL is desired.

  The present invention solves such a conventional problem and provides a capacitor inspection apparatus and an inspection method using the same that can accurately measure the ESL characteristics of a chip-type solid electrolytic capacitor in a very short time. It is for the purpose.

In order to solve the above-described problems, the present invention is an inspection apparatus for inspecting the electrical characteristics of a capacitor having a four-terminal structure configured such that an anode terminal and a cathode terminal are exposed at two locations opposite to each other on a lower surface serving as a mounting surface. In addition, a substrate on which microstrip lines and grounds as signal lines are formed on the surface, a measuring unit for positioning and holding a capacitor to be inspected on this substrate, and a signal from a network analyzer are networked It consists of a signal input unit and a signal output unit that input and output via a coaxial cable connected between the input port and output port of the analyzer via two terminals of a microstrip line and a ground. in 4 in the testing apparatus of the connected capacitors to constitute a terminal circuit network, said microstrip Spline, said one ends of the microstrip line is connected to the signal input portion, the other ends are connected to the signal output unit, the ground formed on the substrate, formed on both sides of the microstrip line There are provided four measurement terminals for inputting / outputting signals by contacting the microstrip line in the measurement unit and the four terminals provided on the lower surface of the capacitor with the ground, and two of the measurement terminals are connected to the microstrip line. The structure is provided on the surface of the stripline .

  As described above, the capacitor inspection apparatus according to the present invention measures the ESL of a chip-type solid electrolytic capacitor with a simple configuration without generating unnecessary impedances such as unnecessary resistors and in a very short time and with high accuracy. The effect of being able to be obtained is obtained.

(Embodiment)
Hereinafter, the invention described in the entire claims of the present invention will be described by using embodiments.

  FIG. 1 is a conceptual diagram showing a configuration of a capacitor inspection apparatus according to an embodiment of the present invention, and FIGS. 2A to 2C are an exploded perspective view and an external perspective view showing a measuring unit of the inspection apparatus. FIG. 3A to FIG. 3C are a perspective view, a plan view, and a rear view showing a substrate constituting the measurement unit, respectively, in a state in which a capacitor as a test object is placed. In FIG. 3, reference numeral 1 denotes a measuring unit, 2 denotes a capacitor as an object to be measured which is placed on the measuring unit 1 and measured. This capacitor 2 has been described with reference to FIG. This is the same as a chip-type solid electrolytic capacitor, and is a surface mounting type with a four-terminal structure configured such that an anode terminal 46a and a cathode terminal 47a are exposed at two locations facing each other on the lower surface serving as a mounting surface.

  Reference numeral 3 denotes a substrate which is a main member constituting the measurement unit 1, and the substrate 3 is made of an insulating material, and a signal is sent to the anode terminal 46 a of the capacitor 2 over the longitudinal direction of the approximate center on the surface side. A 50 Ω microstrip line 4 serving as a signal line for inputting, and a ground 5 serving as a cathode electrode for contacting the cathode terminal 47a of the capacitor 2 are formed by plating. The microstrip line 4 and the ground 5 are not plated, and an insulating portion 6 is provided. Further, the back surface of the substrate 3 is also subjected to the same plating process, and a plurality of through holes (described later). The front and back surfaces of the measurement terminal 7 are electrically connected to each other, and the microstrip line 4 and the ground 5 are formed independently via the insulating portion 6.

  7 is a measurement terminal provided so that one end protrudes to the surface side of the substrate 3 by being implanted in a plurality of through holes provided at predetermined positions of the microstrip line 4 and the ground 5 of the substrate 3. The measurement terminal 7 has a conical tip formed on the surface 3 of the substrate 3, and the conical tip is provided at two opposing locations on the bottom surface of the capacitor 2 that is the object to be inspected. The anode terminal 46a and the cathode terminal 47a (a total of four terminals) are in contact with each other, and two (a total of eight) measurement terminals 7 are provided for each terminal of the capacitor 2. It is what was done.

  In addition, two measuring terminals 7 provided for each terminal are provided at positions close to both ends of each terminal, thereby reducing the distance between adjacent anodes / cathodes and reducing unnecessary resistance as much as possible. It is intended to reduce.

  Reference numeral 8 denotes a guide plate made of an insulating material. The guide plate 8 positions the capacitor 2 at a predetermined position in the measuring unit 1 to perform accurate measurement. Reference numeral 9 denotes a metal fixing base on which the substrate 3 and the guide plate 8 are coupled.

  Reference numeral 10 denotes an input side coaxial connector for inputting a signal to the microstrip line 4 provided on the substrate 3, and 11 denotes an output side coaxial connector for taking out a signal from the microstrip line 4.

  12 is a network analyzer, and 12a and 12b are a first port and a second port of the network analyzer 12. The first port 12a when the input signal is frequency-subtracted and input from the first port 12a with a constant power, and The first port 12a, the input-side coaxial connector 10 and the second port-side coaxial cable are connected via the first port-side coaxial cable 13 so as to obtain the impedance of the measurement unit 1 based on the ratio of the incident wave to the second port 12b and the reflected wave. The second port 12b and the output-side coaxial connector 11 are connected via 14.

  Reference numeral 15 denotes a personal computer (hereinafter referred to as a personal computer 15). The personal computer 15 includes a control unit 16, a calculation unit 17, a display unit 18, and a recording unit 19. The capacitor 2 is loaded and placed on the measuring unit 1, and the supply unit 20 that is taken out and carried out, or the capacitor 2 placed on the measuring unit 1 is urged to be pressed against the measuring unit 1. The pressurizing unit 21 is also controlled at the same time.

  Next, a specific description will be given of a method for measuring ESL using the thus configured capacitor inspection apparatus according to the present embodiment. FIG. 4 is a circuit diagram showing an inspection method using a connection pattern of a capacitor 2 as an object to be inspected in this embodiment, and is generally called a shunt-through measurement method in the measurement using the 2-port method. In the above-described four-terminal network, the signal terminals of each port and the ground terminals of each port are connected, and the capacitor 2 is connected between the center between the connected signal terminals and the ground.

  FIG. 5 is a circuit diagram schematically showing the principle of measuring the ESL of the capacitor 2 using the measurement method shown in FIG. 4, and the capacitor 2 connected in parallel to the constant input / output load 22 is fixed in this way. The first incident wave a1 (24), the first reflected wave b1 (25) to the first port 12a of the network analyzer 12 when the signal whose frequency is inserted from the signal source 23 with power is added, and the first Capacitor 2 by performing an operation using the S parameter expressed by (Equation 1) calculated by the ratio of the second incident wave a2 (26) to the two-port 12b and the second reflected wave b2 (27) The ESL is calculated and obtained. The relationship between the incident waves a1 and a2 and the reflected waves b1 and b2 and the S parameter is expressed by (Expression 2).

  FIG. 6 is a plan view showing a state in which the capacitor 2 is actually mounted on the substrate 3 by the connection method shown in FIG. 4, which is generally referred to as a T type, and has impedances Z1, Z2, and Z3. Assuming that the circuit shown in FIG. 7 is configured by the first impedance element 28, the second impedance element 29, and the third impedance element 30 represented, the capacitor 2 is the second impedance element 29. It is believed that there is. Since Z12 of the first row and second column of the Z parameter represented by (Equation 3) is equal to the impedance Z2 of the first row and second column of the Z parameter corresponding to the T-type circuit, (Equation 4) holds, The impedance Z2 of the capacitor 2 can be obtained using the relationship between the S parameter of Equation 5) and Z12, and the ESL of the capacitor 2 can be calculated therefrom.

  8 and 9 are characteristic diagrams showing the impedance characteristic and ESL characteristic of the capacitor 2 obtained by measurement as described above for reference.

  As described above, the capacitor inspection apparatus and the inspection method using the capacitor according to the present embodiment do not generate unnecessary impedances such as unnecessary resistors with a simple configuration, and the capacitor ESL can be accurately performed in a very short time. In addition, with the configuration in which pin-shaped measurement terminals for inputting / outputting signals in contact with the four terminals provided on the lower surface of the capacitor are implanted in the measurement section, the capacitor terminals and Since the contact state of the measurement terminal can be greatly improved, it is possible to further improve the measurement accuracy.

  INDUSTRIAL APPLICABILITY The capacitor inspection apparatus and the inspection method using the same according to the present invention have an effect that impedance measurement can be performed with high accuracy in a short time, and in particular, a low ESL solid electrolytic capacitor corresponding to higher frequencies It is useful for inspection.

The conceptual diagram which showed the structure of the test | inspection apparatus of the capacitor | condenser by one embodiment of this invention (A) Exploded perspective view showing the measuring unit of the inspection device, (b) External perspective view, (c) External perspective view in a state where a capacitor which is the inspection object is placed. (A) The perspective view which showed the board | substrate which comprises the measurement part, (b) The top view, (c) The back view Circuit diagram showing the inspection method based on the connection pattern of the capacitor Circuit diagram schematically showing the principle of measuring ESL of the capacitor Plan view showing the same capacitor mounted on the board Assumed equivalent circuit diagram of the capacitor Characteristic diagram showing impedance characteristics of the capacitor Characteristic diagram showing the ESL characteristics of the capacitor (A) Plan sectional view showing the configuration of a chip-type solid electrolytic capacitor, (b) Front sectional view, (c) Side sectional view, (d) Bottom sectional view, (e) Bottom view Schematic diagram showing the configuration of a conventional solid electrolytic capacitor measuring device Electrical equivalent circuit diagram of the measuring apparatus shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Measurement part 2 Capacitor 3 Board | substrate 4 Micro strip line 5 Ground 6 Insulation part 7 Measurement terminal 8 Guide board 9 Fixing base 10 Input side coaxial connector 11 Output side coaxial connector 12 Network analyzer 12a 1st port 12b 2nd port 13 1st port Side coaxial cable 14 Second port side coaxial cable 15 Personal computer 16 Control unit 17 Calculation unit 18 Display unit 19 Recording unit 20 Supply unit 21 Pressure unit 22 Input / output load 23 Signal source 24 First incident wave 25 First reflected wave 26 Second incident wave 27 Second reflected wave 28 First impedance element 29 Second impedance element 30 Third impedance element 46a Anode terminal 47a Cathode terminal

Claims (11)

An inspection apparatus for inspecting the electrical characteristics of a capacitor having a four-terminal structure configured such that an anode terminal and a cathode terminal are exposed at two positions opposite to each other on a lower surface serving as a mounting surface, and a microstrip line as a signal line; A substrate on which the ground is formed, a measuring unit for positioning and holding a capacitor to be inspected on the substrate, and a signal from the network analyzer between the input port and the output port of the network analyzer It consists of a signal input unit and a signal output unit that input and output via a coaxial cable connected by two terminals of the microstrip line and the ground. The signal input unit and the signal output unit are connected to form a four-terminal network. in the testing apparatus of capacitors, said microstrip line, said microstrip One end of the line is connected to the signal input portion and the other of said opposite ends being connected to the signal output unit, the ground formed on the substrate, the formed on both sides of the microstrip line, in the measuring section Four measurement terminals for inputting / outputting signals are provided by contacting the microstrip line and ground with the four terminals provided on the lower surface of the capacitor, and two of the measurement terminals are provided on the surface of the microstrip line. inspection apparatus of a capacitor that is. The measuring terminal apparatus for inspecting capacitor according to claim 1 which is a measurement terminal of like pins planted on the microstrip line and ground. The capacitor inspection apparatus according to claim 2 , wherein the pin-shaped measurement terminal has a conical shape in contact with the capacitor terminal. The capacitor inspection apparatus according to claim 2 , wherein two or more pin-shaped measurement terminals are implanted with respect to each terminal of the capacitor. The capacitor inspection apparatus according to claim 1, wherein a guide plate is disposed on the substrate of the measurement unit to place and position and hold a capacitor to be inspected. When a signal is added from the network analyzer, calculation is performed using the S parameter calculated by the ratio of the incident wave and the reflected wave to the input port and output port of the network analyzer, and the impedance (equivalent series) of the capacitor to be inspected is calculated. The capacitor inspection apparatus according to claim 1, further comprising an arithmetic unit that calculates (inductance). The capacitor inspection apparatus according to claim 6 , further comprising a display unit that displays impedance calculated by the calculation unit or information related to the impedance. The capacitor inspection apparatus according to claim 6 , further comprising a control unit that controls the pressure unit or the supply unit based on the impedance calculated by the calculation unit or information related to the impedance. A recording unit that records the impedance calculated by the calculation unit or information related to the impedance is provided, and the control unit performs inspection and management of characteristics and the like of the capacitor to be inspected based on statistics in the recording unit. The capacitor inspection apparatus according to claim 8, which is configured as described above. A capacitor inspection method for inspecting a capacitor having a four-terminal structure , which is configured so that a positive electrode terminal and a negative electrode terminal are exposed to two opposite surfaces on a lower surface serving as a mounting surface , using the inspection device according to claim 1. Te, wherein connecting the anode terminal of the capacitor is a device under test to the microstrip line, by connecting the cathode terminal of the capacitor to the ground, measured by connecting a capacitor between the ground and the microstrip line How to inspect capacitors. The capacitor includes an element laminate in which a plurality of capacitor elements each having an anode electrode portion and a cathode electrode portion are stacked, the cathode electrode portions are stacked, and the anode electrode portions are disposed in opposite directions. 11. The chip-type solid electrolytic capacitor according to claim 10, wherein each of the anode electrode portions arranged in a direction is connected to one of the anode terminals, and the stacked cathode electrode portions are connected to the two cathode terminals. Inspection method for capacitors.

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