Flash memory storage cell and preparation method thereof

Abstract

The invention discloses a flash memory storage cell and a preparation method thereof. The preparation method includes forming gate structures on a substrate and forming a contact window between the gate structures, the preparation of the contact window includes the following steps: depositing and forming an interlayer dielectric layer and photoresist on the substrate having the gate structures; etching the interlayer dielectric layer between the gate structures to a first height position with the photoresist being the mask, and leaving a part of the interlayer dielectric layer between the gate structures; then depositing and forming an isolation layer; etching the isolation layer between the gate structures and the residual interlayer dielectric layer; and filling a conducting material between the gate structures to form the contact window. The interlayer dielectric layer is etched to the first height position, a part of the interlayer dielectric layer is left between the gate structures, and the isolation layer is formed by deposition. The existence of the isolation layer protects a side wall layer from being over-etched in the preparation process of the contact window, thereby preventing a phenomenon that a short circuit occurs between the contact window and a control gate.

Description

technical field [0001] The invention relates to the technical field of semiconductor devices and their manufacture, in particular to a flash memory storage unit and a preparation method thereof. Background technique [0002] At present, the resolution of very large-scale integrated circuit technology has been developed to below 0.18 microns, that is, the ratio of depth to width or diameter is getting larger and larger, and the contact windows of metals and semiconductors are getting smaller and smaller, and the manufacturing process of contact windows has become the largest. One of the difficulties. [0003] In order to overcome the increasingly smaller line width and prevent misalignment of contact windows, many semiconductor devices usually adopt a self-aligned contact window design. Especially in flash memory devices, the source / drain in the substrate is electrically connected to the bit line formed above the substrate, usually using the design of self-aligned contact wi...

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Problems solved by technology

[0004] The present invention aims to provide a flash memory storage unit and its preparation method to solve the technical problem in the prior art that a short circuit between the contact window and the control gate is easily caused in the process of making the contact window by the self-alignment method

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