摘要
多维度折弯在刚挠结合板、多层柔性线路板中已大量运用到智能手机、平板电脑、可穿戴设备等消费电子产品等。应柔性线路区域弯折需求,分层(air-gap)设计成为该类柔性线路板制造中常用设计,但该设计在完成排板压合工序后,板面存在凹陷状高低差现象。同时,为控制提高挠性区域的弯折,软板层采用基铜+孔铜电镀的工艺,因此也形成孔边凸起状高低差。一凹一凸高低差的存在,给线路图形制作带来挑战。本文前期试验通过不同线路前处理、不同干膜厚度、排板压合方式等常规的线路制作方式,未能解决分层(air-gapp)设计带来的凹陷、镀孔台阶高低导致的线路缺陷;中期结合湿膜和干膜各自的优点,实验研究开发出湿膜+干膜工艺,同时,通过优化设计和制作工艺参数,经批量验证有效降低分层(air-gap)和孔镀台阶导致的开路、曝光不良等缺陷,不良率下降8.3%%。后期,通过引入真空贴膜机贴膜的方式,也进行了新的尝试,结果良率进一步提升2.05%。本文所述的图形线路制作方式,为解决刚挠结合板软板层分层(air-gap)区域线路制作提供制作工艺参考。
Multi-dimensional bending has been widely used in rigid-flex boards and multilayer flexible printed circuit boards for consumer electronic products such as smartphones,tablets,wearables,etc.In order to meet the bending demand of the flexible circuit area,the air-gap design has become a common design in the manufacturing of such flexible circuit boards.However,after the completion of the plate arrangement and pressing process,there is a concave height difference on the board surface.At the same time,in order to control and improve the bending of the flexible area,the flex layer adopts the process of base copper+button plating,thus forming a raised height difference at the hole edge.The existence of height difference between concave and convex brings challenges to the production of image process.In the previous experiment of this project,conventional circuit fabrication methods such as different pretreatment,different thickness of dry film,and different pressing methods can not solve the defects caused by the depression which caused by the air layer design and the height of the plated hole edge steps.In the middle stage,combining the advantages of wet film and dry film,the wet film+dry film process was developed through experimental research.At the same time,after optimizing the design and manufacturing process parameters,and the defects such as open circuit and poor exposure caused by air gap were effectively reduced through batch verification.In the later stage,a new attempt was made by introducing a vacuum dry film laminator.The imaging processing method described in this paper provides a reference for the manufacturing process of the air gap area circuit in the flex layer of the rigid-flex board.
作者
叶天保
杨成友
万品亮
萧琳凯
Ye Tianbao;Yang Chengyou;Wan Pinliang;Xiao Linkai
出处
《印制电路信息》
2023年第S01期289-305,共17页
Printed Circuit Information
