CN-122016876-A - Method and device for testing champagne bubbles in surface treatment of silver PCB (printed circuit board), computer equipment and storage medium

CN122016876ACN 122016876 ACN122016876 ACN 122016876ACN-122016876-A

Abstract

The invention discloses a champagne bubble inspection method, a device, computer equipment and a storage medium for surface treatment of silver-plated PCB (printed circuit board). The method comprises the steps of manufacturing a champagne bubble standard sheet, taking part of the standard sheet as a sample to be inspected, carrying out silver precipitation treatment to obtain a silver precipitation standard sheet to be inspected, taking the standard sheet as a calibration sample, carrying out microetching treatment before silver precipitation, carrying out silver precipitation treatment to obtain a silver precipitation X-ray calibration standard sheet, carrying out printing tin paste and reflow soldering treatment to obtain a standard piece to be inspected and an X-ray calibration standard piece, scanning the X-ray calibration standard piece to confirm that the state of X-ray equipment is normal, scanning the standard piece to be inspected, detecting whether an aggregation cavity exists in the edge area of each bonding pad, slicing the standard piece to be inspected to obtain a slicing inspection result, and judging whether current silver precipitation process parameters are qualified. By implementing the method provided by the invention, the full-flow quality control from process verification to batch release can be realized.

Inventors

ZHANG LUNLIANG
HU QINGTING
ZENG YANPING
GUO QUAN
YIN XINGXING
LIU ZIRONG
FANG ZHIQIANG

Assignees

江西景旺精密电路有限公司

Dates

Publication Date: 20260512
Application Date: 20260330

Claims (10)

A method for testing champagne bubbles for surface treatment of silver oxide on a pcb, comprising: designing and manufacturing a silver-plated champagne bubble standard sheet with a double-sided structure, wherein the top surface and the bottom surface of the standard sheet are respectively provided with a plurality of non-solder-resist definition copper pads with different sizes; Taking a part of the standard sheets as samples to be tested, carrying out conventional silver precipitation treatment on the standard sheets by a silver precipitation production line to obtain silver precipitation standard sheets to be tested, taking at least one standard sheet as a calibration sample, carrying out microetching treatment on the copper surface of a bonding pad of the calibration sample before silver precipitation, and carrying out silver precipitation treatment on the copper surface by the same silver precipitation production line to obtain silver precipitation X-ray calibration standard sheets; Printing solder paste and reflow soldering treatment are respectively carried out on the silver-depositing to-be-measured standard piece and the silver-depositing X-ray calibration standard piece, so as to obtain a to-be-measured standard piece and an X-ray calibration standard piece; Scanning the X-ray calibration standard component by using X-ray equipment, and verifying whether the equipment can identify a simulation cavity with a preset size on the calibration standard component so as to confirm that the state of the X-ray equipment is normal; Under the condition that the equipment state is normal, scanning the standard component to be detected by adopting the X-ray equipment, and detecting whether champagne bubble type gathering cavities exist in the edge area of each bonding pad to obtain a detection result; When the detection result meets the slicing verification triggering condition, slicing the standard component to be detected, and observing the cavity morphology at the silver-tin alloy layer interface under a microscope to obtain a slicing detection result; And judging whether the current silver deposition process parameters are qualified according to the slicing inspection result, and if so, allowing PCB mass production according to the same parameters.
2. The silver-plated surface-treated champagne bubble inspection method of claim 1, wherein a scanning magnification of said X-ray apparatus is not less than 60 times, and an equivalent diameter of a simulated void in said X-ray calibration standard is not less than 15 μm.
3. The silver-plated surface treated champagne bubble inspection method of claim 1, wherein said pad edge region refers to an annular region that is 25% wide from the pad edge by the corresponding side or diameter of the pad.
4. The silver-plated surface-treated champagne bubble inspection method of claim 1, wherein the dicing verification triggering condition is that 3 or more voids having a diameter of more than 20 μm exist in an edge region of any one pad, or that the total coverage area of voids in the edge region exceeds 10% of the area of the region.
5. The method for testing a champagne bubble for surface treatment of silver PCB according to claim 1, wherein the determination of the slicing test result is performed under a magnification of 200 times or more, and the qualification condition is that voids are all located in the silver-tin alloy layer and the interface of the silver-tin alloy layer and the copper layer is taken as a determination boundary, and any one of the following conditions is satisfied: A single void size of 15-30 μm and a number of less than 5; the size of the cavity is less than 15 mu m and the number of the cavities is less than 20; At the same time, the aggregate width of all the voids along the edge direction of the pad is not more than 25% of the corresponding pad width.
6. The method for testing the surface treatment champagne bubble of the silver PCB according to claim 1, wherein the microetching treatment is to adopt microetching liquid formed by mixing 98wt% sulfuric acid, 30wt% hydrogen peroxide and pure water according to a preset proportion, and to carry out microetching roughening treatment on the copper surface of a bonding pad of a calibration sample.
7. The method for testing the champagne bubble after the surface treatment of the silver PCB according to claim 1, wherein the printing of the solder paste is to use a steel mesh with the thickness of 125 μm, the opening size of the steel mesh is consistent with the size of a bonding pad, the thickness of the solder paste is controlled to be 40 μm to 70 μm through the steel mesh printing, and the reflow soldering is to use a preset reflow soldering temperature curve for one-time reflow soldering.
A champagne bubble inspection device for surface treatment of silver oxide on a pcb, comprising: the manufacturing unit is used for designing and manufacturing a silver-plated champagne bubble standard sheet of a double-sided structure, and the top surface and the bottom surface of the standard sheet are respectively provided with a plurality of non-solder-resist definition copper bonding pads with different sizes; The processing unit is used for taking part of the standard sheets as samples to be tested, carrying out conventional silver precipitation treatment on the standard sheets by a silver precipitation production line to obtain silver precipitation standard sheets to be tested, taking at least one piece of the standard sheets as calibration samples, carrying out microetching treatment on the copper surfaces of bonding pads of the calibration samples before silver precipitation, and carrying out silver precipitation treatment on the calibration samples by the same silver precipitation production line to obtain silver precipitation X-ray calibration standard sheets; the printing and welding unit is used for respectively carrying out printing solder paste and reflow soldering treatment on the silver-depositing to-be-measured standard piece and the silver-depositing X-ray calibration standard piece to obtain a to-be-measured standard piece and an X-ray calibration standard piece; The scanning verification unit is used for scanning the X-ray calibration standard component by using X-ray equipment, and verifying whether the equipment can identify a simulation cavity with a preset size on the calibration standard component so as to confirm that the state of the X-ray equipment is normal; The scanning detection unit is used for scanning the standard component to be detected by adopting the X-ray equipment under the condition that the equipment state is normal, and detecting whether champagne bubble type gathering cavities exist in the edge area of each bonding pad to obtain a detection result; The slice observation unit is used for slicing the standard component to be detected when the detection result meets the slice verification triggering condition, and observing the cavity morphology at the silver-tin alloy layer interface under a microscope to obtain a slice detection result; And the judging unit is used for judging whether the current silver deposition process parameters are qualified according to the slicing inspection result, and if so, the PCB mass production is allowed to be carried out according to the same parameters.
9. A computer device, characterized in that it comprises a memory on which a computer program is stored and a processor which, when executing the computer program, implements the method according to any of claims 1-7.
10. A storage medium storing a computer program which, when executed by a processor, implements the method of any one of claims 1 to 7.

Description

Method and device for testing champagne bubbles in surface treatment of silver PCB (printed circuit board), computer equipment and storage medium Technical Field The invention relates to the technical field of PCB silver-plating inspection, in particular to a method, a device, computer equipment and a storage medium for testing surface treatment champagne bubbles of PCB silver-plating. Background A Printed Circuit Board (PCB) is a core basic component in the field of electronic manufacturing, and its surface treatment process directly determines the soldering reliability of the subsequent Surface Mount (SMT). As a widely applied surface treatment mode, the chemical Silver (ImAg) has the advantages of high surface flatness, excellent weldability, good high-frequency signal transmission performance, moderate cost and the like, and is particularly suitable for high-end application scenes such as fine circuits, BGA/QFN packaging, high-speed high-frequency circuit boards, automobile electronics and the like. The basic principle of electroless silver deposition is based on the displacement reaction between copper and silver ions, in which copper (Cu) loses electrons and is dissolved by oxidation, while silver ions (Ag +) gain electrons to be reduced to metallic silver and deposited on the copper surface. However, in the actual production process, if the copper surface has residual glue, microetching residues or organic pollutants, the local pollution layer can fall off and expose the fresh copper surface in the silver deposition process, so that different areas of the copper surface form electrochemical activity differences, and further the local anode area is induced to generate galvanic corrosion. The etched area is then covered with a silver layer, forming micro-pits (also known as "holes") in the oxidation state with a size of about 1 μm. In addition, if microetching control is improper in the pretreatment stage, or the silver precipitation reaction condition is out of control (such as parameters of liquid medicine concentration, temperature, time and the like deviate from a process window), the phenomenon of 'super etching' can be initiated, and the generation density and depth of the micro pits are further increased. In the subsequent SMT reflow soldering process, the silver layer is quickly dissolved into the solder at high temperature, the soldering flux permeates into the micro-pits and undergoes a reduction reaction with the residual oxide, gases such as CO 2, water vapor and the like are generated in the reaction process, and the gases cannot escape in time due to the rapid solidification rate of the welding spot and are finally wrapped at the interface of the intermetallic compound (IMC, mainly Cu 6Sn5) and the solder to form planar micro-cavities, which are commonly called as champagne bubbles in the industry. Although the micro-scale of the micro-cavity is small, the effective wetting area between the bonding pad and the pin of the component is obviously reduced. When the area ratio of the micro-cavity exceeds a threshold value, the welding strength is reduced, and the components are caused to fall off when serious, so that the electrical connection is finally invalid, the reliability of the product is reduced, and even the function is failed. Although the silver-dissolving technology is widely applied, the PCB industry still lacks a standardized, quantifiable silver-dissolving champagne bubble inspection method and a judgment criterion which are suitable for mass production. The existing detection means depend on experience judgment or post failure analysis, and effective process monitoring and risk early warning cannot be realized at the front end of the silver precipitation process. Therefore, development of a silver-stabilized champagne bubble inspection method which can accurately simulate actual welding conditions, can be repeatedly verified, and has definite acceptance criteria is needed to improve the welding reliability of silver-plated plates and guarantee the consistency of product quality. Disclosure of Invention The invention aims to overcome the defects of the prior art and provides a champagne bubble inspection method, a champagne bubble inspection device, computer equipment and a storage medium for surface treatment of silver PCB. In order to achieve the above purpose, the present invention adopts the following technical scheme: The method for testing the champagne foam of the surface treatment of the silver PCB comprises the following steps: designing and manufacturing a silver-plated champagne bubble standard sheet with a double-sided structure, wherein the top surface and the bottom surface of the standard sheet are respectively provided with a plurality of non-solder-resist definition copper pads with different sizes; Taking a part of the standard sheets as samples to be tested, carrying out conventional silver precipitation treatment on the standard sheets by a silver precipitat