Polymer Surface Micropatteming And Selectively Deposition Of Copper On Patterned Surface

Nowadays, microcontrol of surface properties and microstructure fabrication within micro-or nanoscaled areas plays an increasingly important role in the development of science and technology. A lot of technologies root in the fabrication of new-style microstructure or miniaturization of existing configuration. The industry requirements of ever-decreasing feature size and increasing off-chip frequency combine to change the needs of metal/polymer interfaces. Polymer surface roughness, for instance, has historically been used to improve adhesion through mechanical anchoring with negligible effects on performance; however, in systems with small features and high frequencies this will no longer be the case. High levels of roughness make feature and line fabrication difficult as feature sizes shrink to the same scale as the roughness, while high frequency signals have greater scatter and loss along rough surfaces. Thus, as the feature size shrinks and off-chip frequency increases, the interface between the metal and dielectric material must become smoother. At the same time, adhesion must be maintained to avoid metal delamination and loss of package reliability.On the one hand,172nm UV light was used for modifying PET surface and fabricating topological structure after APTES grafting on PET surface. On the other hand, electroless copper plating technology was used for depositing macrocopper pattern on PET surface. The specific content is as follows:1. PET surface was modified by172nm UV light, and then APTES SAM was grafted onto PTE surface. Water contact angle test, ninhydrin reaction and XPS test demonstrate that PET surface modification was successful. The decrease of PET surface water contact angle and the increase of hydrophilicity were confirmed by water contact angle test, and the contact angle would be continuously decreasing until the photoirradiation time reached6minutes. Numbers of hydroxyl groups were produced on PET surface, which was necessary for APTES grafting onto PET surface.2. The electroless copper plating formular was optimized by orthogonal test. The results showed that components of electroless plating and plating technology had direct effects on the copper layer. The optimized formulation contains two parts. Solution A contained3g of CuSO4,14g of potassium tartrate (Rochelle salt), and4g of NaOH in100mL distilled water. Solution B was an aqueous formaldehyde solution (37.2wt%). The two solution were mixed in a ratio10:1(v/v) ratio just before the bath was used. The palting temperature was60℃and plating time was1min.3. Topological microstructure of APTES SAM on PET surface was fabricated by172nm VUV etching techolonogy. And then, copper micropattems were deposited on the PET surface and observed by optical microscope, SEM, AFM. The result indicates that the copper micropatterns have a highfidelity and good uniformity.In this paper,172nm UV light technology and self-assemble monolayer technology were used for modifying PET surface and fabricating topological microstructure. An orthogonal design experiment was utilized for the optimization of formula, and worked out an appropriate formula and plating technology. Highfidelity and good uniformity copper micropatterns are obtained. It provided the possibility of innovative designing of submicron circuit.