The DNA chip is required of high sensitivity and low cost for practical medical service. We have tried to use polycarbonate (PC) included TiO_2 as a substrate of DNA chip for low cost. However, the PC included TiO_2 cannot adhere DNA easily due to their hydrophobicity. In this work, in order to change the PC included TiO_2 to be hydrophilicity, At, N_2 and O_2 ions were irradiated on the surface of specimen by using an Electron Cyclotron Resonance (ECR) ion shower apparatus. We measured the contact angle of water on the surface of specimens with an optical microscope. Surface morphology of specimens were observed by a SEM, and measured by an AFM. Surface of specimen was analyzed by X-Ray photoelectron spectrometry (XPS). Then we measured adhesion force of DNA probe to the surface of specimen by force curve measurement using the AFM in water. The contact angle of untreated specimen were decreased and reached to 8deg. by N_2 and O_2 ion irradiation. The surface roughness of untreated specimen were increased and reached to 248nmRa by N_2 ion irradiation. The hydrophilic property was kept during 1440 hours in air by 2 times irradiation of O_2 ion. XPS showed that hydrophobic groups were formed on the surface of specimens by N_2 ion irradiation. The adhesion force of DNA probe to the surface of specimen was increase by seven times larger than the untreated one by 4 times irradiation of N_2 ion.
