How to make a pip capacitor

Abstract

The invention provides a method for making a PIP (Poly-Insulator-Poly) capacitor, which includes the following steps: providing a substrate which is divided into a storage area and a logic area, and forming a coupling oxide layer, a floating gate layer, a first medium layer, a control gate layer and floating gate silicon nitride successively on the substrate; using the etching layout of the floating gate silicon nitride to etch the floating gate silicon nitride; forming floating gate side walls covering the outside of the etched floating gate silicon nitride, and forming floating gate displacement spacers and tunneling oxide layers which cover the floating gate side walls; forming word lines; forming protective silicon nitride and protective silicon oxide to cover the word lines; removingthe protective silicon nitride and the protective silicon oxide in the logic area, and partially etching the floating gate silicon nitride; forming logic gate silicon oxide in the logic area to coverthe etched floating gate silicon nitride and the word lines; and forming logic gate poly-silicon to cover the logic gate silicon oxide. By adding the etching layout of the floating gate silicon nitride to etch the floating gate silicon nitride, a flat poly-silicon surface can be obtained.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a method for manufacturing a PIP capacitor. Background technique [0002] PIP (poly-insulator-poly, polysilicon-insulator-polysilicon) capacitor is a device widely used to prevent analog circuits from emitting noise and frequency modulation. PIP capacitors are often used in embedded flash memory technology with multi-layer polysilicon, because of their large capacitance per unit area, which can effectively reduce the chip area. In the embedded flash memory process, word line polysilicon, logic gate polysilicon and high voltage gate oxide are often used to form a PIP structure. Currently in the 90nm NORD flash process platform, the word line polysilicon (Word line Poly-Silicon) uses a chemical mechanical polishing process (CMP) to remove the polysilicon in areas other than the word line. Because the CMP process will form a large dishing in a large grinding removal area (s...

AI Technical Summary

Problems solved by technology

Because the CMP process will form a large dishing in the large grinding removal area (such as poly-silicon), resulting in the inability to obtain a flat polysilicon plane

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