The present invention is directed to an apparatus and process for heating and cooling semiconductor wafers in thermal processing chambers. According to the present invention, agglomerates of poly-3-hydroxyalkanoic acid are obtained by adjusting the pH of an aqueous poly-3-hydroxyalkanoic acid suspension to fall within an acidic region. The null will determine angle for elevation toward the optimum satellite and azimuth or heading. are covered by an insulator serving as a high frequency power propagator while the surface of the insulator is covered completely by a conductive member except at the portion for introducing the high frequency power. The bore is configured providing a section having a reduced wall thickness, between the threaded portion and the bore closed end, for purposes of providing a preferential stress relief mechanism.