Photochemical Nucleation of Copper on Polyimide Surface with 10ns Laser Irradiation - Growth of Copper Metal on Copper Nuclei and Deposition of SiO2 film on Copper Metal

Abstract

AbstractCopper atoms were substituted on the polyimide surface in the presence of CuSO4 solution with only 10ns single shot of ArF laser. Then, we have succeeded in substituting copper atoms with dangling bonds of carbon cross- linking with oxygen atoms. In this study, we placed fused silica glass on the polyimide surface firstly, and poured the sulfate solution into the gap between the silica glass and the film, forming a thin liquid layer. Then, one shot of circuit patterned ArF laser light having 42mJ/cm2 was irradiated vertically onto the sample. The photon is dissociating and exciting the copper sulfate solution and the polyimide surface. The dissociated copper atoms form the C-O-Cu bond with active oxygen on the polyimide surface. However, we were able to grow a copper thin film of about 24μm after immersing the sample into the electro less plating solution for 15 minutes at 60.On the other hand, we have laminated transparent and low dielectric constant SiO2 film at room temperature on polyimide surface by using Xe2 excimer lamp. Then, the copper film deposited on polyimide film and the piece of silicon were placed in the reaction chamber with mixing NF3 and O2 gasses in the ratio of 10:1; total pressure 330 Torr. Then, Xe2 excimer lamp was irradiated for 20 minutes. By the photochemical reaction, SiF4 and NO2 were produced. The adsorbed SiF4 on copper and polyimide surface of one molecule layer and NO2 up react with NO2, and growth SiO2 film on the sample surface. A chain reaction of film formation is brought about by these two chemical reactions of adsorption and oxidization. By this film formation film thickness was not more than 600 after 20 minutes with the Xe2 excimer lamp irradiation in order to lose in SiF4. Then, the silicon was supplied, and insufficient SiF4 was filled by ablating the silicon wafer by focused ArF excimer laser beam.