摘要:
In order to form an oxide cover on a conductive filling in a trench in a semiconductor substrate an HDP oxide is deposited on the conductive filling using a PECVD method. In this case, the layer thickness on the horizontal surface of the conductive material is greater than the layer thickness on the sidewalls of the trench. Furthermore, the layer thickness is limited in such a way that the surface of the HDP oxide within the trench has a depth with respect to the surface of the semiconductor substrate surrounding the trench, or a layer disposed thereon. In a subsequent CMP step, the HDP oxide is removed from the surrounding surface. In an isotropic etching step, the HDP oxide is removed from the sidewalls. The result is a horizontal insulation layer with a layer thickness that varies only to a slight extent over the semiconductor substrate.