Temperature measurement of polymer substrates during plasma irradiation

In the web coating process of some materials using sputtering, plasma-assis ted evaporation, and plasma-enhanced C VD, heat damage of polymer substrate s by plasma irradiation is problem for the quality of products. During depo sition, the substrate is heated by condensation of deposits, heat from the source or plasmas, and so on. However, it is difficult to distinguish these processes and the change of the temperature plasma irradiation must be min imized. In this paper, we have researched the effect of discharge condition s on the plasma heating of the polymer substrate independently of the other heat sources. The Ar, O-2 and N-2 plasmas were created by AC discharge wit h magnetic field using web coating. PET(Polyethylene terephthalate) substra te was passed through the plasma region at different conditions, such as ga seous species, pressure, discharge pou er. and web speed. The temperature o f the substrate was measured using thermometer before and after passing thr ough the plasma region. Ln ordinary case, the temperature of the substrate increased immediately when the substrate entered the plasma region and had the maximum at the center of the plasma region. When the power input increa sed, the temperature slightly increased in both plasmas. Pressure also affe cted the increment of thr substrate temperature. The change of the web spee d influenced upon the residence time of the substrate in the plasma region. In this experimental conditions, although the temperature change of the su bstrate were 0.4-3 degrees C, this would not ignore for the polymer substra te. The change of the substrate temperature passing through plasma region w ill be discussed together with the results of plasma diagnostics and some t he surface analysis of the substrate. (C) 1999 Elsevier Science S.A. All ri ghts reserved.