Application Research On Second Order Copper Filling HDL Printed Circuit Boards Based On Minitab Software

At present, miniaturization and integration are the trends of the electronic products,putting forward strict requirements for the encapsulation technology which is developedgradually from Surface Mounting Technology (SMT) to Chip Scale Package (CSP).Because of the demand for higher electronic interconnection density of CSP than that ofSMT, which requires higher connection density of inner layers and surface layers ofprinted circuit board (PCB), the High Density Interconnection Technology (HDI) hasbeen developed in recent years as research focus for PCB manufacturers and researchers.HDI printed board has usually been defined as a kind of high-end PCB in which thethicknesses of conductive and insulator layer are less than0.025mm and0.075mmrespectively, the conductor line/space and the through hole diameter is no more than0.1mm/0.1mm and0.15mm respectively, and the Input/Output (I/O) nμmber is morethan300. Second order porefilling HDI printed board, which brings the Ball Grid Array(BGA) arrangement from out layer into inner layer and fills holes via plating blind holesto strengthen the conduction capability among layers, can solve the technical difficultiesof high density arrangement of singular out layer BGA and microvia conduction.Meanwhile, the better thermal dissipation performance of porefilling via plating blindhole can promote the high frequency transmission performance, achieving high fidelityof signal.This study focused on developing second order porefilling HDI printed board usingporefilling technology via plating blind hole. By using the horizontal pulse plating lineto fill blind holes, the plating parameters such as positive and negative current densityratio(A) and pulse time ratio(B), the concentrations of Cu2+(C)and brightener(D) whichwere considered as influencing factors on porefilling quality were studied throughFactorial Design of the quality management statistics software Minitab15. Bestmanufacturing parameters were achieved via analysis of Factorial Design of Minitab15where the positive and negative current density ratio and pulse time ratio were5/30and15/1respectively, and the concentrations of Cu2+and brightener were70g/l and10ml/lrespectively. Regression analysis and residual analysis were conducted by Minitab15software.The regression equation was “Y=-14.9+87.2×A+0.677×B-0.0427×C-0.180×D” withcorrelation coefficient(R)97.4%which meant the equation was significant，there wasalso no abnormal data in Residual Analysis. The linear fitted equation about the relationamong porefilling dimple value and each influencing factor would direct the platingprocesses design theoretically. Demonstration test was carried out to validate bestmanufacturing parameters and the results showed that the Dimple value of porefillingwas7.59μm, meeting customer’s requirement of Dimple value (≤15μm). Solder FloatTest and Thermal Shock Test were implemented to evaluate the reliability of secondorder porefilling HDI printed board, showing that second order porefilling HDI printedboard met the reliability requirements in aspect of plating porefilling quality completely.Besides, to appraise the stability of plating porefilling process when manufacturingsecond order porefilling HDI printed board, sample test was done and analyzed byNormality Test and Process Capability Analysis of Minitab15Software. The resultsshowed that the Complex Process Capability index Cpk was5.49, meaning highstability of plating porefilling process. The development and batch production import ofsecond order porefilling HDI printed board were accomplished successfully, bringinggood economic benefit and social benefit to our enterprise.C#language was used to develop a automatic maintenance software of solution inoxidation vat of horizontal pulse plating line. Once the automatic maintenance softwarewas started, the maintenance of oxidation vat solution was executed automatically.Consequently, error probability caused by worker’s operarion in oxidation vat solutionmaintenance process reduced and the normal production of production line was ensured,improving the production efficiency and product qualification rate. The qualified rate ofproducts is increased from the original91%to99.9%.In the developing process of second order copper filling HDI printed board, byusing Minitab15Software to arrange and analyze experiment scientifically, the effectof plating parameters on plating porefilling quality was studied scientifically andefficiently. Data model was achieved to direct subsequent plating processes designtheoretically and the development of plating porefilling technology was accomplishedsuccessfully.