An integrated circuit is fabricated with a layer of polysilicon located on top of shallow trench regions. The polysilicon is patterned so that the trench features are not exposed during an etching operation performed on the polysilicon layer. The process of fabricating transistor gate electrodes, therefore, is improved by reducing etch byproducts contributed by the shallow trench region features.
RELATED INVENTION
The present invention is related to the following invention which is assigned to the same assignee as the present invention:
Ser. No. 09/691,932, filed Oct. 19, 2000 entitled "Integrated Circuit Processing Having Dummy Features", which is a divisional of the present invention, which is a Div of Ser. No. 09/223,078, filed Dec. 29, 1998.
A semiconductor device and a method of forming thereof include a dummy active region positioned adjacent the device active region. The dummy active region is formed to include an oxide layer of a thickness that is less than the oxide layer of the active region such that excess charge accumulated during etching in the active region is conducted through the dummy active region into the substrate. In this manner, the dummy active region operates as a charge sink during formation of the active region to prevent premature deterioration of the gate oxide layer of the active region.
An integrated circuit device is fabricated by forming at least one isolation region in an area of a semiconductor substrate, such as a monolithic semiconductor substrate or a silicon on insulator (SOI) substrate. The at least one isolation region defines at least one active region. A plurality of dummy conductive regions is distributed in the area of the semiconductor substrate, with the dummy conductive regions being constrained to overlie the at least one isolation region. The dummy conductive regions may be formed from a conductive layer that is also used to form, for example, a gate electrode, a capacitor electrode or a wiring pattern. The dummy conductive regions may be formed on an insulation layer, e.g., a gate insulation layer or an interlayer dielectric layer. Preferably, the dummy conductive regions are noncontiguous. In one embodiment, a lattice-shaped isolation region is formed including an array of node regions linked by interconnecting regions and defining an array of dummy active regions. The plurality of dummy conductive regions are formed on the node regions of the lattice-shaped isolation region. In another embodiment, an array of isolation regions is formed, defining a lattice-shaped dummy active region. An array of dummy conductive regions is formed on the array of isolation regions. Related integrated circuit devices are also described.
A model-based approach for generating an etch pattern to decrease topographical uniformity involves placing reverse dummy features (50, 52, 70) in a region of a semiconductor substrate (40, 60) according to the topography of the region and adjacent regions. The reverse dummy features are placed inconsistently over the semiconductor substrate (40, 60) because the need for reverse dummy features is inconsistent and varies from design to design. In one embodiment, the reverse dummy features (50, 52, 70) having varying widths are placed with varying spacing between them and are placed in different regions. The determination of location, size and spacing of the reverse dummy features (50, 52, 70) is determined based upon the uniformity effect over the entire semiconductor die and may be used in conjunction with the placement of printed dummy features. After placing the reverse dummy features (50, 52, 70), a planarization process may be performed to remove the reverse dummy features, which improves the planarization.