Preparation of functional properties on the substrate for electronics by environmentally friendly surface modification.

印刷电路板（PCB）已经被要求更高的密度和更多的集成度，因为许多电子设备已经变得小型化和多功能化。对于更高的密度，PCB应该在基板和导电层之间具有足够的粘附力，以保持光滑的表面，从而实现更精细的图案化。新开发的以TiO_2为光催化剂的紫外光表面改性方法在不增加基材粗糙度的情况下，实现了1.17kgf/cm的优异附着强度。本文报道了一种在线路板（PCB）上制作线间距为10μm/10μm的精细图形的方法。以TiO_2为光催化剂，在紫外光照射下，对PCB进行了深度为20-30 nm的表面改性。此外，证实了作为催化剂的钯（Pd）和锡（Sn）渗透到表面改性层中，并且在该层的底部开始化学镀铜（Cu）。因此，认为优异的附着力源于PCB与存款铜之间形成的共存层的纳米级锚效应。因此，用这种新的表面改性方法代替刻蚀，再进行常规的预处理，实际上可以制作出线条和间距为10μm/10μm的精细图形。通过引入新的表面改性，形成精细的线路电路，而不粗糙化的PCB表面和没有多余的沉积观察线之间的对比，与传统的方法。结果表明，这种新方法具有形成更精细图案化PCB的内在优势。

Printed circuit boards(PCBs) have been required higher density and more integration, since many electronic devices have become downsized and multi-functionalized. For higher density, PCBs should have enough adhesion between substrate and conductive layer maintaining the smooth surface for finer patterning. Newly developed surface modification using TiO_2 powder as a photocatalyst and UV irradiation has realized excellent adhesion strength of 1.17kgf/cm without increasing roughness of substrate. This paper reported a mechanism of excellent adhesion and fabrication of fine patterns on PCBs with line and space of 10μm/10μm. Modified surface of PCBs in depth of 20-30 nm was created by the irradiation of UV light under the presence of TiO_2 as a photocatalyst. Moreover, it is confirmed that palladium(Pd) and tin(Sn) as the catalyst were penetrated into the surface modified layer and electroless copper(Cu) plating was initiated at the bottom of this layer. Therefore, it is suggested that excellent adhesion was originated from nano-level anchor effect by the formation of co-existed layer between PCBs and deposit copper. Accordingly, fine patterns with line and space of 10μm/10μm were actually fabricated by using the new surface modification in place of etching and followed by conventional pre-treatment. By introducing the new surface modification, fine line circuits was formed without roughening the surface of PCB and no extraneous deposition was observed between lines in contrast to the conventional method. It is concluded that this new method has intrinsic advantage for the formation of finer pattered PCBs.