Goto, Tetsuya, et al. Journal of Vacuum Science & Technology A, 2020, 38(1), 013002.
The resistance of fluoroelastomer (FKM) and perfluoroelastomer (FFKM) to CF4/O2 plasma, a common process in semiconductor manufacturing, was studied. The results show that both FKM and FFKM are eroded by low-energy (less than 10 eV) ion bombardment. For FKM elastomer, neutral radical attack is also the dominant factor that increases elastomer corrosion, while FFKM elastomer is much better than FKM elastomer in terms of stability against neutral radicals. These results will be very useful when considering the material selection of O-rings at different locations in plasma equipment.
Plasma irradiation test for FKM and FFKM samples
· For the plasma irradiation test, two types of elastomer samples, FKM and FFKM, were prepared. Each sample was made into a 13-mm diameter coupon with a thickness of 2 mm.
· The samples were placed on a 200-mm diameter wafer using double-sided polyimide tape in the plasma chamber. The plasma was then activated and each plasma irradiation session lasted 5 minutes, with a 5-minute break in between. This process was repeated 12 times, resulting in a total of 60 minutes of plasma irradiation for each plasma condition.
· The temperature of the elastomer sample was measured at 105°C during the 5-minute plasma irradiation using a thermo label. After the plasma irradiation, the weight loss of the elastomer samples was measured with a precision balance, and the surface morphology was analyzed using a scanning electron microscope (SEM).
