Application Research On Plating Throwing Power For Printed Circuit Boards Based On Minitab Software

As the high multiplayer board, backplane and system HDI are applied to computerand communication, more challenges have been brought to the process of those boardswhich have high layers, high thickness and little aperture. To ensure the copper platingperformance of the via hole has become an important part of the reliability assurance,and one of the important index in estimating high aspect ratio PCB is throwing power.As a result, it is great important to study on how to promote the throw powering ofPCB.This article analyzes the factors that influence on throw powering of PCB from theaspects of people，machine，material，method and environment, and use Minitab tomake a study of the plating liquid concentration, current density, organic additivecomposition and vibration frequency. On the basis, use Minitab to study the four factorson throw powering with the taguchi-method. The test results are as follows:（1）The factors that affect on the throw powering are plating liquid concentration,current density, organic additive composition and vibration frequency. Theconcentration of the plating liquid should be high-acid and low-copper ion. Low currentdensity is beneficial to promote the throw powering, but it can not be too low, it is easyto make the copper crystallization rough, and the more serious result is crystal structurebecome column structure. With the effect of brightener and leveler, not only to promotethe throw powering, but also to enhance the copper plating ductility. Vibrationfrequency can change the flow of solution, effect the exchange of solution in hole, andpromote the throw powering.（2）Through the Minitab software analysis, acid copper ratio from40g/l to35g/l,PCB throwing power ability increased an average of4%-5%; With the increase of thecurrent density, PCB throwing power ability decreased gradually, descending graderange up to5%; The brightener concentration from120ml/kAH to60ml/kAH, can meetthe high aspect ratio PCB boards production requirements; Different vibrationfrequency from10s to30s, throwing power ability gradually increased.（3）Using taguchi-method to experimental design and analysis with Minitab software, the throwing power effect sequence are current density--copper sulfateconcentrations--light agent content--vibration frequency. In order to make the PCBthrowing power ability to achieve the best, should choose the plating density is5ASF,copper sulfate concentration is30g/L, brightener concentration is60ml/kAH, thevibration frequency of30s, can make the PCB throwing power ability to achieve thebest.Using Minitab software to the PCB throwing power ability results show that thedetailed understanding of throwing power are benefit for high aspect ratio PCBproduction.