Method for improving process window of self-aligned cell module in SONOS technology

Abstract

The invention discloses a structure for improving a process window of a self-aligned cell module in SONOS technology and a manufacturing method thereof. The structure is characterized in that: the structure comprises film layer structures of a shallow trench isolation module and a self-aligned cell etching (SACE) module; a non-doped oxidation layer is adopted as an interlayer film medium; and phosphate glass is adopted as a field space medium. The method can avoid a series of process difficulties brought by flower pattern introduced when the phosphate glass is used as a PMD interlayer film medium, so that the process window of the whole module is improved greatly.

Description

technical field [0001] The invention relates to the field of semiconductor integrated circuit manufacturing. Background technique [0002] At present, the film layer structure of the advanced SONOS (silicon oxynitride silicon) self-aligned empty module is usually composed of undoped oxide film and phosphoric acid glass ( figure 2 ). Its advantage is that by introducing the special pre-metal dielectric of phosphate glass and the special dry etching process, it has a high selectivity ratio of phosphate glass to undoped oxide film, omitting the nitrogen necessary in the traditional process The compound etching barrier layer is used to further reduce the chip area and improve the integration level of the product. However, the "bud-shaped shell" brought about by this structure has brought great challenges to the entire process module. In order to meet the requirements, other important process steps such as the size of the metal gate, the film thickness of the sidewall dielectr...

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Problems solved by technology

Obviously it is very challenging to improve the process window of the whole module

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