PCB aging test method

Abstract

The invention discloses a PCB (Printed Circuit Board) aging test method, which comprises the following steps of: acquiring PCB information of a test sample, and preprocessing the test sample; placing the test sample in an aging oven for accelerated aging test, recording test environment parameters in real time in the test process, and monitoring electrical performance parameters of the PCB; the accelerated aging test method is determined according to the PCB information and comprises at least one of temperature, humidity, voltage and current aging tests; comparing the monitored electrical performance parameters of the PCB with the aging test standard requirements, comparing and analyzing the mechanical performance and thermal performance parameters before and after the aging test, and evaluating whether the parameters meet the aging test requirements or not; and for the PCB which does not meet the aging test requirement, analyzing and determining the reason for the performance abnormity of the PCB according to the performance change of the PCB. According to the PCB aging test method provided by the invention, the aging state of the PCB can be comprehensively evaluated, so that the reliability of the PCB is improved, and the service life of the PCB is prolonged.

Description

Technical Field

[0001] The invention relates to the technical field of circuit board detection, and in particular to a PCB board aging test method. Background Art

[0002] With the rapid development of electronic technology, printed circuit boards (PCBs), as the core components of electronic devices, have been widely used in various fields. However, with the increasing complexity and integration of PCBs, their quality and reliability issues have become increasingly prominent. During long-term use, PCBs may be affected by a variety of environmental factors such as temperature, humidity, and voltage, resulting in performance degradation, malfunctions, or even failure.

[0003] Traditional PCB inspection methods mainly include visual inspection, functional testing, and reliability testing, etc. Although these methods can detect defects in PCBs to a certain extent, they cannot fully evaluate the aging status of PCBs and other issues, and thus cannot correctly evaluate the reliability and life of PCBs.

[0004] In view of this, an object of the present invention is to provide a PCB board aging test method for comprehensively evaluating the aging performance of the PCB board. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a PCB board aging test method, which can comprehensively evaluate the aging state of the PCB board, thereby improving its reliability and service life.

[0006] The technical solution of the present invention is as follows:

[0007] A PCB board aging test method comprises the following steps:

[0008] Step S1, obtaining PCB board information of the test sample and preprocessing the test sample;

[0009] Step S2, placing the test sample in an aging box for accelerated aging test, recording the test environment parameters in real time during the test, and monitoring the electrical performance parameters of the PCB board; the accelerated aging test method is determined according to the PCB board information, including at least one of temperature, humidity, and voltage and current aging tests, wherein:

[0010] Temperature test: place the PCB board in a high temperature environment of 50-85℃, a low temperature environment of -10℃~-40℃, and a high and low temperature cycle environment for aging tests, and generate different temperature conditions;

[0011] Humidity test: The PCB board is placed in a high humidity environment of 85-95%, a low humidity environment of 10-30%, and a high humidity and low humidity cycle environment for aging test, and the electrical performance curves under different humidity conditions are generated;

[0012] Voltage and current test: The PCB board is subjected to a test voltage higher than the normal working voltage, a test current higher than the normal working current, and a simulated transient overvoltage or transient overcurrent for aging tests, and the electrical performance curves under different voltage and current conditions are generated;

[0013] Step S3, comparing the monitored electrical performance parameters of the PCB board with the requirements of the aging test standard, and comparing and analyzing the mechanical properties and thermal performance parameters before and after the aging test to evaluate whether they meet the aging test requirements;

[0014] Step S4, for the PCB board that does not meet the aging test requirements, analyze and determine the cause of the abnormal performance of the PCB board according to its performance change.

[0015] Furthermore, the PCB board information includes product model, serial number, production date and test environment.

[0016] Furthermore, in step S1, the PCB board pretreatment includes cleaning and drying processes.

[0017] Furthermore, in step S2, the test environment parameters include temperature, humidity and air pressure.

[0018] Compared with the prior art, the PCB board aging test method provided by the present invention has the following beneficial effects:

[0019] The PCB board aging test method provided by the present invention performs accelerated aging tests on the PCB board including temperature, humidity, voltage and current, and comprehensively evaluates the aging state of the PCB board, thereby ensuring the reliability and service life of the PCB board. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to better understand the technical solutions in the embodiments of the present invention and to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the specific implementation modes of the present invention are further described below.

[0021] It should be noted that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation of the present invention. In addition, the technical features involved in each embodiment of the present invention described below can be combined with each other as long as there is no conflict between them.

[0022] A PCB board aging test method comprises the following steps:

[0023] Step S1, obtaining PCB board information of the test sample and preprocessing the test sample;

[0024] Specifically, representative samples are randomly selected from the production batch to ensure that the samples can reflect the overall production situation. The sampled PCB board samples are uniquely identified, including product model, number, production date, test environment and other information to ensure the traceability of the test process. After selecting the test samples, the samples are first pre-processed, including cleaning and drying processes, to eliminate potential interference factors.

[0025] Step S2, placing the test sample in an aging box for accelerated aging test, recording the test environment parameters in real time during the test, and monitoring the electrical performance parameters of the PCB board; the accelerated aging test method is determined according to the PCB board information, including at least one of temperature, humidity, and voltage and current aging tests, wherein:

[0026] Temperature test: The PCB board is placed in a high temperature environment of 50-85℃, a low temperature environment of -10℃~-40℃, and a high and low temperature cycle environment for aging tests to detect the electrical performance and stability under high and low temperature conditions, as well as the reliability and durability under temperature change conditions, and form an electrical performance curve under different temperature conditions;

[0027] Humidity test: The PCB board is placed in a high humidity environment of 85-95%, a low humidity environment of 10-30%, and a high humidity and low humidity cycle environment for aging tests to detect the electrical performance and insulation performance of the PCB board under humid conditions, as well as the working state under low humidity conditions, and the reliability and stability under humidity change conditions, and to form an electrical performance curve under different humidity conditions;

[0028] Electrical performance test: The PCB board is subjected to aging tests by applying a test voltage higher than the normal working voltage, a test current higher than the normal working current, and simulating transient overvoltage or transient overcurrent, respectively, to detect the voltage withstand capability, current carrying capacity, and reliability of the PCB board protection circuit and components, and to form electrical performance curves under different voltage and current conditions;

[0029] The electrical performance parameters include:

[0030] The thickness of the copper on the circuit board affects the conductivity and corrosion resistance of the circuit board. Before the production of the circuit board, the base copper foil commonly used for the substrate is 1 / 3oz (12um), H / Hoz (15um), 1oz (35um), etc. The final thickness of the base copper substrate after the whole set of processing is about 43um, 52um and 64um.

[0031] Solder mask thickness, the solder mask thickness C2 on the copper foil is about 8-10um, and the solder mask thickness C1 in the area without copper foil on the surface varies according to the surface copper thickness. When the surface copper thickness is 45um, C1 is about 13-15um, and when the surface copper thickness is 70um, C1 is about 17-18um. The thickness of the solder mask affects the insulation performance and welding reliability of the circuit board. A thicker solder mask can improve the insulation performance, but it may affect the wire impedance and welding quality.

[0032] The conductor cross section is actually a trapezoid. Taking the TOP layer as an example, when the copper foil thickness is 1OZ, the upper bottom side of the trapezoid is 1MIL shorter than the lower bottom side. For example, when the line width is 5MIL, its upper bottom side is about 4MIL and the lower bottom side is 5MIL. The conductor cross section affects the current carrying capacity and signal transmission speed of the circuit board. The trapezoidal conductor cross section design can optimize the current distribution and increase the signal transmission speed.

[0033] Dielectric constant, the dielectric constant of the prepreg is related to the thickness, the dielectric constant of the FR4 board is 4.2-4.7, and it decreases with the increase of frequency. The dielectric constant affects the signal transmission speed and the size of the circuit board. A lower dielectric constant can increase the signal transmission speed, but it will increase the size of the circuit board.

[0034] Volume resistivity ρv represents the quotient of the DC electric field strength and the steady-state current density in the insulating material, the volume resistance per unit volume. The commonly used standard is ≥106MΩ·cm after moisture protection and ≥103MΩ·cm at high temperature 2 .

[0035] Surface resistivity ρs represents the quotient of the DC electric field strength and the line current density in the surface layer of the insulating material, and the surface resistance per unit area. The commonly used standard is ≥104MΩ after moisture protection and ≥103MΩ at high temperature. Volume resistivity and surface resistivity affect the insulation performance and current distribution of the circuit board. Higher volume resistivity and surface resistivity can improve the insulation performance of the circuit board, but will affect the current distribution and transmission speed.

[0036] Step S3, comparing the collected electrical performance parameters of the PCB board with the requirements of the aging test standard, and comparing and analyzing the mechanical properties and thermal performance parameters before and after the aging test to evaluate whether they meet the aging test requirements;

[0037] If the electrical performance parameters tested are within the requirements of the aging test standards, and the mechanical and thermal performance parameters after the aging test are within a reasonable range, the PCB board meets the composite aging test requirements. Otherwise, the PCB board does not meet the aging test requirements. The reliability of the same batch of products can be judged by the ratio of samples that meet the aging test requirements.

[0038] Step S4, for PCB boards that do not meet the aging test requirements, analyze and determine the reasons for abnormal performance of the PCB boards according to their performance changes, such as poor welding, component failure, improper material selection, unreasonable process parameter settings, etc., so as to further improve the production process of the batch of PCB boards to improve product quality.

[0039] Therefore, the PCB board aging test method provided by the present invention can comprehensively evaluate the aging state of the PCB board, thereby improving its reliability and service life.

[0040] The embodiments of the present invention are described in detail above, but the present invention is not limited to the described embodiments. For those skilled in the art, various changes, modifications, substitutions and variations made to these embodiments without departing from the principles and spirit of the present invention are still within the protection scope of the present invention.

Claims

1. A PCB board aging test method, characterized in that: The steps include: Step S1, obtaining PCB board information of the test sample and preprocessing the test sample; Step S2, placing the test sample in an aging box for accelerated aging test, recording the test environment parameters in real time during the test, and monitoring the electrical performance parameters of the PCB board; The accelerated aging test method is determined according to the PCB board information, including at least one of temperature, humidity, and voltage and current aging tests, wherein: Temperature test: The PCB board is placed in a high temperature environment of 50-85℃, a low temperature environment of -10℃~-40℃, and a high and low temperature cycle environment for aging tests, and the electrical performance curves under different temperature conditions are generated; Humidity test: The PCB board is placed in a high humidity environment of 85-95%, a low humidity environment of 10-30%, and a high humidity and low humidity cycle environment for aging test, and the electrical performance curves under different humidity conditions are generated; Voltage and current test: The PCB board is subjected to a test voltage higher than the normal operating voltage, a test current higher than the normal operating current, and a simulated transient overvoltage or transient overcurrent for aging tests, and the electrical performance curves under different voltage and current conditions are generated; Step S3, comparing the monitored electrical performance parameters of the PCB board with the requirements of the aging test standard, and comparing and analyzing the mechanical properties and thermal performance parameters before and after the aging test to evaluate whether they meet the aging test requirements; Step S4, for the PCB board that does not meet the aging test requirements, analyze and determine the cause of the abnormal performance of the PCB board according to its performance change.

2. The PCB board aging test method according to claim 1, characterized in that: PCB board information includes product model, serial number, production date and test environment.

3. The PCB board aging test method according to claim 1, characterized in that: In step S1, the PCB board pretreatment includes cleaning and drying processes.

4. The PCB board aging test method according to claim 1, characterized in that: In step S2, the test environment parameters include temperature, humidity and air pressure.