Novel RIE Back Planarization
Original Publication Date: 1992-May-01
Included in the Prior Art Database: 2005-Mar-22
A process for planarizing polymer dielectrics over integrated circuit device topography while providing an etch stop for subsequent contact hole Reactive Ion Etching (RIE) is described. The process is shown schematically in Fig. 1 and begins with deposition of a conformal oxide and polymer layer (polyimide) over the device topography. Following this, low molecular weight polystyrene is spun applied on the wafer and reflowed to planarize the structure. This structure is then subjected to O2 RIE to etch back the structure and planarize the polyimide. The fact that both materials being etched back are polymeric minimizes the control necessary to perform this step. Subsequent lithographic patterning and RIE provide contact holes with a conformal etch stop (the SiO2) to the polymer O2 RIE.