| 摘要 |
Attorney Docket Number 53.1057 ENHANCED DENSITY MODIFIED ISOPLANAR PROCESS An improved process for fabricating modified isoplanar integrated circuits with enhanced density incorporates a number of interactive and co-acting process steps. First, oxide isolation of epitaxial islands is effected in a two step process, forming a thin thermally grown oxide layer over the surfaces of shallow trenches and then filling the shallow trenches with deposited low temperature oxide. Second, an enhanced single polycrystalline or polysilicon layer process uses a blanket implant, eliminates certain masking and etching steps, and defines the polycrystalline layer for greater and more efficient use in resistor, transistor, and related circuit interconnects and elements of the integrated circuit structure. Third, a new method and structure is provided for dielectrically isolating and separating contact locations on different surface levels of the integrated circuit structure adjacent to step locations between the surface levels. Spacer shoulders of dielectric material are formed at the step locations separating contact locations on the lower surface level of the monosilicon epitaxial layer from contact locations on the upper surface level of the polysilicon layer by anisotropic etching of a blanket conformal spacer layer of dielectric material. Finally, a new method constitutes all of the electrical contact locations for the elements of the integrated circuit structure at the same substantially isoplanar level. This is accomplished by bridging from contact locations on the lower surface level of the monosilicon epitaxial layer to transfer contact locations on the polysilicon layer. Polycrystalline islands provide the transfer contact locations and the spacer shoulders at the polycrystalline islands provide sites for bridges or strips of titanium or other refractory metal used in siliciding the contact locations. |
