Semiconductor integrated circuit processing wafer having a PECVD material layer of improved thickness uniformity

摘要

A semiconductor integrated circuit is made by a process including the formation on a surface of a semiconductor integrated circuit processing wafer of a layer of material applied to the wafer by plasma enhanced chemical vapor deposition (PECVD). The layer of material may include plural sub-layers, the thicknesses of which are additive to result in the thickness of the layer of material itself. The sub-layers of material may have non-uniform thicknesses across a dimension of the processing wafer because of compromises in the process which are necessary to control various parameters of the material layer other than its thickness. These non-uniformities of thickness of the sub-layers may be controlled to offset one another so that the resulting layer of material has a substantially uniform thickness across the dimension of the processing wafer. A method, and apparatus for practicing the method, are set forth along with an explanation of how particular geometric factors of electrodes used in the PECVD process affect the resulting thickness non- uniformities. The thickness non-uniformities of the sub- layers may also be largely abated by use of the invention in a predictive- corrective fashion. A similar predictive-corrective method and resulting apparatus is set forth for gas plasma etching of an existing layer of material on a semiconductor integrated circuit processing wafer.