高厚径比通盲共镀新技术开发

Development of new technology of blind Co-plating with High thickness-diameter ratio

随着高精度、高密度和高可靠性的112 G、三次能源产品需求量与日俱增,作为其载体的印制电路板(Printed circuit board,PCB)也向高密度互联(High density interconnection,HDI)方向发展。此类印制电路板通过通孔、盲孔、埋孔的金属化实现层与层之间电气互联。对于高厚径比通孔和盲孔的金属化过程是先电镀盲孔,再电镀通孔,此流程涉及多次电镀多次减铜多次塞孔,不仅流程繁琐复杂,而且多次增铜损铜不利于精密线路设计,难以满足高可靠性、高密度的要求。本文通过对高厚径比通孔电镀体系与盲孔电镀体系系统分析,从药水以及喷流两方面找到通盲共镀的矛盾点并加以平衡:一方面基于铜离子、氢离子以及添加剂的药水机理进行DOE实验,开发得到新的电镀药水体系;另一方面通过建立与优化喷流-铜厚模型图对侧喷喷流方式进行创新性设计,并参考模型图将喷流参数进行适当调整;以上述设计为基础进行试验,结果表明通孔25:1,盲孔1.2:1的产品通盲共镀具有良好的适应性和有效性。该电镀体系的达成,实现了高厚径比通盲共镀技术新突破,缩短加工流程23步,解决了面铜极差的问题,满足精细线路制作,同时对PCB工业与产品,特别是高密度互联的产品走向规模化发展提供了有力保障!。

With the increasing demand of 112G and tertiary energy products with high precision,high density and high reliability,the printed circuit board(PCB)as its carrier is also developing in the direction of high-density interconnection.This kind of printed circuit board realizes the electrical interconnection between layers through the metallization of through holes,blind holes and buried holes.The metallization process of high aspect ratio through hole and blind hole is:first electroplating blind hole,then electroplating through hole.This process involves electroplating multi times to reduce copper and plug holes for many times.The process is not only tedious and complicated,but also increases copper loss many times and is not conducive to precision circuit design.It is difficult to meet the requirements of high reliability and high density.In this paper,through the systematic analysis of high aspect ratio through-hole plating system and blind-hole plating system,the contradiction of blind co-plating is found and balanced from two aspects:on the one hand,DOE experiments are carried out based on the potion mechanism of copper ion,hydrogen ion and additives,and a new electroplating solution system is developed.On the other hand,the side jet mode is innovatively designed by establishing and optimizing the jet-copper thickness model diagram,and the jet parameters are properly adjusted with reference to the model diagram.Based on the above design,experiments are carried out,and the results show that the through-hole 25:1 blind co-plating of 1.2 blind hole has good adaptability and effectiveness.The achievement of the electroplating system has achieved a new breakthrough in the high aspect ratio blind co-plating technology,shortened the processing flow by 23 steps,solved the problem of poor surface copper,satisfied the fine circuit production,and provided a strong guarantee for the large-scale development of PCB industry and products,especially high-density interconnected products.