The present invention is directed to the design of a plasma CVD chamber which provides more uniform conditions for forming thin CVD films on a substrate. Embodiments of the invention improve temperature control of the upper chamber and improve particle performance by reducing or minimizing the temperature fluctuations on the dome between the deposition and non-deposition cycles. This allows higher source power plasma to be generated and facilitates gapfill for extremely small geometries. The dome design improves the uniformity of the plasma distribution over the substrate to be processed. In accordance with an aspect of the present invention, an apparatus for processing semiconductor substrates comprises a chamber defining a plasma processing region therein. The chamber includes a bottom, a side wall, and a dome disposed on top of the side wall. The dome has a dome top and having a side portion defining a chamber diameter. A top RF coil is disposed above the dome top. A side RF coil is disposed adjacent the side portion of the dome. The side RF coil is spaced from the top RF coil by a coil separation. A ratio of the coil separation to the chamber diameter is typically at least about 0.15, more desirably about 0.2-0.25. In some embodiments, a vacuum system includes a pump and a throttle gate valve disposed in a lower chamber portion of the chamber near the bottom. A screen previously disposed below the gate valve may be moved above the gate valve to facilitate cleaning and reduce particulates.