An electrostatic chuck for securing a semiconductor wafer on a pedestal having multiple apertures for the introduction of cooling gas beneath the wafer. The multiple apertures reduce overheating near the wafer edge and provide lower temperature gradients across the wafer. The wafer is held by electrostatic force against a laminate of an electrode layer sandwiched between two dielectric layers in such a way that the laminate presents a planar surface to the wafer for a substantial distance beyond the outer edge of the electrode layer. The laminate construction ensures that a large wafer area beyond the outer edge of the electrode is in contact with the laminate, to minimize cooling gas leakage near the edge, and provides a longer useful life by increasing the path length of dielectric material between the electrode layer and potentially damaging plasma material surrounding the chuck.