Selective Plasma Surface Modification of Resist for Patterning Hydrophobic and Hydrophilic Regions

A plasma surface modification process was investigated to realize a fine pattern on a surface that consists of highly controlled hydrophilic and hydrophobic areas. Capacitively and inductively coupled plasmas (CCP and ICP) using CF4 and argon gases were used to increase the hydrophobicity of a resist surface selectively on an indium tin oxide (ITO) surface. By plasma exposure, both the hydrophobicity of the resist and the hydrophilicity of the ITO surface were increased. The difference between the contact angle of water on the plasma-exposed surface of the resist and that on the ITO surface was larger in ICP than in CCP. On the basis of the results of the plasma analyses and X-ray photoelectron spectroscopy of the surfaces, this difference is considered to be due to the high densities of CF3 and CF3+ generated in ICP with the generation of CF2, CF, CF2+, and CF+ at reduced amounts because of the low electron temperature in ICP.