CN213090677U - Measuring device for surface coating of printed circuit board - Google Patents
Measuring device for surface coating of printed circuit board Download PDFInfo
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- CN213090677U CN213090677U CN202022468299.7U CN202022468299U CN213090677U CN 213090677 U CN213090677 U CN 213090677U CN 202022468299 U CN202022468299 U CN 202022468299U CN 213090677 U CN213090677 U CN 213090677U
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Abstract
The utility model provides a measuring device for the surface coating of a printed circuit board, which comprises a first cavity and a second cavity, wherein the first cavity is provided with an electrolyte tank, a three-electrode unit and a temperature control unit; the second chamber is internally provided with a galvanostat and an internal calibration unit, the three-electrode unit comprises a working electrode, a reference electrode and a counter electrode, and the three-electrode unit is placed in the electrolyte tank during working; the temperature control unit is used for controlling the temperature of electrolyte in the electrolyte tank, the galvanostat is used for providing continuous and constant current for the working electrode and the counter electrode, monitoring the potential of the working electrode measured by the reference electrode, drawing a curve of the electrode potential changing along with time according to the potential of the working electrode, and the internal calibration unit is used for calibrating and self-detecting the galvanostat.
Description
Technical Field
The utility model belongs to printed circuit board surface coating measurement analysis field, specifically speaking relates to a printed circuit board surface coating's measuring device.
Background
Along with the intensive circuit board lines and the function integration development, the requirement on the uniformity of the surface coating thickness is higher and higher, and an X-ray fluorescence thickness measuring instrument has certain limitation because the X-ray fluorescence thickness measuring instrument is sensitive to the interference of materials on the inner layer of a test board and certain pure metal layer and intermetallic phase compounds cannot be distinguished. In order to distinguish and measure the thickness of the pure metal layer and the thickness of the intermetallic phase compound layer more accurately, so as to reflect and monitor the production condition more truly, and ensure the product quality and the failure analysis after sale, it is necessary to design an electrochemical analysis mode surface coating measuring device.
SUMMERY OF THE UTILITY MODEL
The utility model aims to provide a measuring device for the surface coating of a printed circuit board, which comprises a first chamber and a second chamber,
the first chamber is provided with an electrolyte tank, a three-electrode unit and a temperature control unit,
a galvanostat and an internal calibration unit are arranged in the second chamber,
the three-electrode unit comprises a working electrode, a reference electrode and a counter electrode, and is placed in the electrolyte tank when in work,
the temperature control unit is used for controlling the temperature of the electrolyte in the electrolyte tank,
the galvanostat is used for enabling the current input into the working electrode and the counter electrode to be continuous and constant, monitoring the potential of the working electrode measured by the reference electrode, drawing a curve of the electrode potential changing along with time according to the potential of the working electrode,
the internal calibration unit is used for calibrating and self-detecting the galvanostat.
Preferably, the device for measuring the surface coating of the printed circuit board further comprises an external inspection instrument, which is located outside the second chamber, electrically connected to the internal calibration unit, and inspects the internal calibration unit.
Preferably, the external detection instrument is a multimeter.
Preferably, the side wall of the second chamber is provided with a voltage interface and a COM port for accessing an external detection instrument.
Preferably, the device for measuring the surface plating of the printed circuit board further comprises an operating unit located outside the second chamber for inputting measurement parameters and displaying measurement results.
Preferably, the operation unit is a computer.
Preferably, the side wall of the second chamber is further provided with an operating unit port for accessing an operating unit.
Preferably, the internal calibration unit includes a metal film resistor whose electrical properties do not change with time.
Preferably, the temperature control unit includes a heater and a temperature sensor.
Preferably, the device for measuring the surface coating of the printed circuit board further comprises a third chamber for storing the components of the device for measuring the surface coating of the printed circuit board.
Preferably, the working electrode, the reference electrode and the counter electrode are removable.
Preferably, the electrolyte tank comprises a valve for replacing the electrolyte in the electrolyte tank.
Preferably, the working electrode is selected from gold-plated materials,
preferably, the counter electrode is selected from platinum,
preferably, the reference electrode is selected from a silver material.
The measuring device of the present invention can operate in oxidation and reduction modes, which can provide thickness information of pure metal layers and the following possible intermetallic phase compounds. The layer detected during the measurement is irreversibly removed. The reduction mode is used to determine the surface condition of the metal layer, the oxide layer is measured and quantified, and all reducing elements (e.g., oxides, sulfides) are successively removed from the surface of the printed wiring board during the measurement process.
In the oxidation mode, for thickness detection, a surface of known area is immersed in an anodic solution using a suitable electrolyte to which a constant current is applied. Complete dissolution of the metal layer can be detected by a change in the electrode potential. The current is proportional to the mass of metal that is oxidized. By this process, all the metal layers can be removed from the substrate in succession under the action of the current and the supporting electrolyte, respectively.
In the reduction mode, the measurement follows the same principle as in the oxidation mode, but in the process the coating (e.g. such as a metal oxide) on the surface of the metal layer is reduced by cathodic current. In this mode the reducing element (e.g. oxide) will be assigned a specific potential and removed from the surface during the measurement.
The time at which a specific potential is present at the electrode during oxidation or reduction of the coating is recorded. The time during which this potential lasts after the constant current is applied is called the phase inversion time t. The relationship between the oxidation or reduction masses is determined according to Faraday's law. For metallic or non-metallic coatings, the molecular weight M, the number of electrons n and the density ρ are constants. The plating thickness d depends only on the applied current i and the area a from which the plating is stripped, which is determined by the length and width of the pad on the test specimen. Therefore, the thickness can be obtained by the following equation.
The utility model provides a printing plate surface coating measuring device utilizes the curve of the electrode potential that three electrode unit obtained along with time variation to through the operating unit demonstration and operation, the user as long as utilize above-mentioned formula can be convenient, swift, accurate analysis relevant surface coating's thickness.
Therefore, the utility model discloses following beneficial effect has been reached:
the measuring device of the utility model can accurately measure the thickness of the surface coating of the printed circuit board, and simultaneously, the internal calibration unit and the external detection instrument are convenient and rapid, thereby constantly ensuring the reliability of the measurement of the instrument; the temperature control unit can maintain the stability of the measurement environment of the electrolyte.
Drawings
In order to illustrate the embodiments of the present invention more clearly, the following figures will be briefly described, and it is to be understood that the following figures are only one embodiment of the present invention.
Fig. 1 is a schematic structural diagram of a Printed Circuit Board (PCB) surface plating measuring device according to an embodiment of the present invention.
Detailed Description
In the description of the utility model, the main material for preparing the electrolyte tank can be PP, PVC, quartz glass material.
In the description of the present invention, the heater in the electrolyte tank may be a heater for heating liquid as is common in the art.
In the description of the present invention, the working electrode includes but is not limited to gold-plated material, the counter electrode includes but is not limited to platinum material, and the reference electrode includes but is not limited to silver material.
In the description of the present invention, the surface plating of the printed wiring board includes, but is not limited to, a pure metal layer (e.g., tin, silver), an intermetallic compound layer (e.g., Cu)XSnY) And oxide layers (e.g., SuO, CuO, Cu)2O). When the plating types on the surface of the printed circuit board are different, the electrolyte is also replaced by the corresponding electrolyte.
The utility model discloses an in the description, the galvanostat can export specific continuation, invariable electric current (for example, 10 mu A ~ 10mA) to counter electrode and working electrode to the control is according to the working electrode potential that reference electrode measured, draws the curve of electrode potential along with time change, accurate calculation electric quantity.
The utility model discloses an in the description, inside calibration unit is used for at any time calibrating and oneself's detection to the galvanostat.
In the description of the present invention, since the correct measurement result is based on the change of the accurate measurement current with time, the internal calibration unit calibrates the measurement accuracy of the current and the voltage with its metal film resistance (e.g., 1000 ± 0.05% Ohm), and its electrical property does not change with time.
The present invention will be described in detail with reference to the accompanying drawings.
As shown in fig. 1, the measuring device 1 for the surface coating of the printed circuit board of the present invention includes a first chamber 10, a second chamber 20, and a third chamber 30.
The first chamber 10 is provided therein with an electrolyte bath 11, a working electrode 121, a reference electrode 122 and a counter electrode 123 constituting a three-electrode unit 12, and a temperature control unit 13. The temperature control unit 13 includes a heater 131 and a temperature sensor 132. The heater 131 is connected to a temperature sensor 132, and the temperature sensor 132 is used to detect the temperature of the electrolyte in the electrolyte tank 11 and judge the relationship between the detected temperature and a set temperature, and if the temperature sensor 132 senses that the temperature of the electrolyte is lower than the set temperature, the heater 131 is energized to heat the electrolyte, and if the temperature sensor 132 senses that the temperature of the electrolyte is equal to or higher than the set temperature, the heater 131 is de-energized to stop heating the electrolyte. A valve 14 is arranged on the side wall of the electrolyte tank 11, the electrolyte in the electrolyte tank 11 can be discharged through the valve 14, and new electrolyte is injected by taking out the working electrode 121, namely the electrolyte in the electrolyte tank is replaced.
The working electrode 121, the reference electrode 122 and the counter electrode 123 are all removable electrodes, and one end of each electrode is designed to be a pluggable port (for example, the three electrodes are inserted into the electrolyte tank in a manner similar to a bottle stopper-bottle mouth), so that the electrodes are convenient to plug and pull, and are easier to replace and clean.
The second chamber 20 is provided with a galvanostat 21 and an internal calibration unit 22. Galvanostat 21 allows the current input to working electrode 121 and counter electrode 123 to be constant, and monitors the working electrode potential measured by reference electrode 122, from which the electrode potential is plotted against time. The internal calibration unit 22 functions to perform internal calibration and self-test of the galvanostat 21. In the embodiment shown in FIG. 1, the internal calibration unit 22 has a metal film resistor with a stable resistance, an electrical property that does not change with time, and a resistance of 1000 + -0.1% Ohm. The utility model discloses a when measuring device calibrated, communicate galvanostat 21 and inside calibration unit 22, open circuit potential compensation, inside calibration unit 22 detects and calibrates negative potential digital-to-analog converter to galvanostat 21's positive potential digital-to-analog converter, negative potential digital-to-analog converter and current amplifier respectively, then the degree of accuracy of self-detection voltage under the constant voltage mode to detect the integrality of electric quantity output.
The device 1 for measuring the surface coating of a printed circuit board as shown in fig. 1 further comprises an external detection instrument 31 (for example, a multimeter) and a computer 32. The multimeter is used to detect the resistance of the internal calibration unit 22, measuring the resistance of the calibration unit 22 over a range greater than 1 kOhm. The computer 32 is used for inputting operation parameters and displaying the result.
The outer surface of the second chamber 20 is further provided with a temperature setting and adjusting knob 23 and a temperature display screen 24, which are connected with the heater 131 and the temperature sensor 132, respectively, for setting or adjusting the heating temperature and displaying the temperature of the electrolyte. The side wall of the second chamber 20 is further provided with a voltage interface 25, a COM port 25', an operating unit port 26 and a power supply port 27. The voltage interface 25, the COM port 25' are used to access the external detection instrument 31 to connect the internal calibration unit 22 with the external detection instrument 31. The operation unit port 26 is used for connecting the computer 32 so as to connect the galvanostat 21 with the computer 32. The power supply port 27 connects the measuring apparatus 1 to an external power supply (for example, 220V power supply) through a wire. The side wall of the second chamber 20 is also provided with a main switch 28 for controlling the on-off state of the entire measuring device 1.
The third chamber 30 is used for storing the components of the measuring device for the surface coating of the printed circuit board. For example, working electrode 121, reference electrode 122, and counter electrode 123 can be removed from first chamber 10 and placed in third chamber 30 when the measurement device is not in operation.
The working process of utilizing the measuring device to measure the surface coating of the printed circuit board sample at fixed points is as follows:
firstly, a proper amount of corresponding electrolyte is added into an electrolyte tank 11 through a notch of a working electrode 121, a to-be-tested printed circuit board sample is clamped on the working electrode and is placed into the electrolyte tank, then, the type of a plating layer (for example, one of Ag, AgX, Sn, SnX and CuO) on the surface of the to-be-tested printed circuit board is selected through an application program interface on a computer 32, the testing temperature is set, whether each part of the measuring device is normal or not is detected, after the normal work of each part is confirmed, a start button on a computer screen is clicked or a space key is pressed to start measurement, a curve of electrode potential changing along with time appears in a main window of an application program, and the plating layer thickness can be obtained according to the curve and the thickness calculation formula.
The basic principles and the main features of the invention and the advantages of the invention have been shown and described above. It will be understood by those skilled in the art that the present invention is not limited to the above embodiments, and that the foregoing embodiments and descriptions are provided only to illustrate the principles of the present invention without departing from the spirit and scope of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (10)
1. A measuring device for the surface coating of a printed circuit board is characterized by comprising a first chamber and a second chamber,
an electrolyte tank, a three-electrode unit and a temperature control unit are arranged in the first chamber,
the second chamber is provided with a galvanostat and an internal calibration unit,
the three-electrode unit comprises a working electrode, a reference electrode and a counter electrode, and when in work, the three-electrode unit is placed in the electrolyte tank,
the temperature control unit is used for controlling the temperature of the electrolyte in the electrolyte tank,
the galvanostat is used for enabling the current input into the working electrode and the counter electrode to be continuous and constant, monitoring the potential of the working electrode measured by the reference electrode, drawing a curve of the electrode potential changing along with time according to the potential of the working electrode,
the internal calibration unit is used for calibrating and self-detecting the galvanostat.
2. The apparatus of claim 1, further comprising an external inspection device, which is located outside the second chamber, electrically connected to the internal calibration unit, and inspects the internal calibration unit.
3. The apparatus for measuring surface plating of printed wiring board as claimed in claim 2, wherein said external inspection instrument is a multimeter.
4. The apparatus for measuring the surface coating of the printed circuit board according to claim 2, wherein the side wall of the second chamber is provided with a voltage interface and a COM port for accessing the external inspection instrument.
5. The apparatus for measuring surface plating of printed wiring board as claimed in claim 1 or 2, further comprising an operation unit located outside the second chamber for inputting measurement parameters and displaying measurement results.
6. The apparatus for measuring surface plating of printed wiring board as claimed in claim 5, wherein said operation unit is a computer.
7. The apparatus for measuring surface plating of printed wiring board of claim 5, wherein the sidewall of the second chamber is further provided with an operating unit port for accessing the operating unit.
8. The apparatus for measuring surface plating of printed wiring board as claimed in claim 1 or 2, wherein the temperature control unit includes a heater and a temperature sensor.
9. The apparatus for measuring surface plating of printed wiring board according to claim 1 or 2, further comprising a third chamber for storing parts of the apparatus for measuring surface plating of printed wiring board.
10. The apparatus for measuring surface plating of printed wiring board according to claim 1 or 2, wherein the working electrode, the reference electrode and the counter electrode are removable.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022468299.7U CN213090677U (en) | 2020-10-30 | 2020-10-30 | Measuring device for surface coating of printed circuit board |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202022468299.7U CN213090677U (en) | 2020-10-30 | 2020-10-30 | Measuring device for surface coating of printed circuit board |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN213090677U true CN213090677U (en) | 2021-04-30 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202022468299.7U Active CN213090677U (en) | 2020-10-30 | 2020-10-30 | Measuring device for surface coating of printed circuit board |
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| Country | Link |
|---|---|
| CN (1) | CN213090677U (en) |
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- 2020-10-30 CN CN202022468299.7U patent/CN213090677U/en active Active
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