We report on a new type of whispering gallery mode (WGM) resonator made of out of low-loss polymer poly (methyl methacrylate) (PMMA). These optical cavities are fabricated using standard semiconductor processing methods in combination with a specific thermal reflow process. During this subsequent thermal treatment, surface tension leads to the goblet like geometry of the resonator and to an ultra smooth surface. The Q-factor of these goblet resonators is above 2·106 in the 1310 nm wavelength range. In order to demonstrate the applicability of the goblet resonators for bio sensing, Bovine Serum Albumin was detected by monitoring the shift of resonator modes due to protein adsorption.