一种内层焊盘外露的挠性多层板制作工艺

A kind of multilayer flex circuits designed with pads opening engineering

现在越来越多的挠性多层板采用分层设计（内层焊盘外露），即将插拔手指、压屏手指或需打件的焊盘设计在内层，该类产品主要围绕如何保护内层线路的外露部分来设计。但常规挠性制作工艺存在一些不足，使用抗蚀刻油墨则有油墨残留、成本高和槽孔保护能力不足的问题：使用干膜保护则有干膜不耐高温高压的问题，使用高温胶带则有对位不准和生产效率低的问题。文章介绍了一种挠性多层板新工艺。工程设计时外层基材对应内层露出的位置不开窗用作保护层，外层线路加工后利用挠性覆铜板基材PI易撕裂的特性，使用手撕揭盖法去除多余部分，不仅完整的保护内层外露的手指、焊盘，还提高了产品可靠性。且生产效率高。

Nowadays, more and more multilayer flex circuits have air-gap design （Inner layer pads opening）, that is to design the contact finger or plugged-in pads in inner layer. This kind of product is designed mainly on how to protect the exposed parts. However, there are some shortcomings in the FPC manufacturing processes： for example, using anti-etching ink has ink residual on pads, high production cost and the low protection ability for slot; dryflimis not resistant to high temperature and pressure issue as it is used to protect the opening pads.There is alignment inaccuracy problem for using high temperature adhesive tape to protect the opening pads. This paper introduces a new technology for multilayer flex circuits. The position of the base material in outer layer is corresponding to the padsin inner layer designed without opening as a protective layer. Polyimide is easy to cut with characteristics after outer layer process, by using the manual de-cap method to remove the redundant parts, which not only protects the contact finger and pads, but also improves the reliability of the products, and the production efficiency is high.