Method for etching suspending type etch blocking layer contact hole in embedded flash memory device

Abstract

The invention discloses an etching method for contact holes of a suspended type etching barrier layer of an embedded flash memory device and comprises the following steps: the first step is the etching of top silicon oxy-nitride; the second step is the fast main etching of an oxide film; the third step is the slow main etching of the oxide film: in the step, the selectivity-ratio of silicon oxide to silicon nitride is bigger than 20:1, while the etching rate is relatively slower; the fourth step is to remove polymers which are produced in the previous three steps and are left at bottom parts of the contact holes; the fifth step is to remove the suspended type etching barrier layer of the nitride silicon; the sixth step is the etching of the oxide film at the bottom part. The invention solves the problem of excessive loss of metal contact silicide on the top part of a poly gate due to no etching barrier layer; at the same time, the invention can effectively avoid excessive etching and communication of the poly gate and an isolated edge of a shallow groove caused by deviation of exposing positions, thus the loss of electric leakage of the device can be reduced.

Description

technical field [0001] The invention relates to an integrated circuit semiconductor manufacturing process method, in particular to an etching method for a contact hole of a suspended etching barrier layer in an embedded flash memory device. Background technique [0002] In the manufacturing process of radio frequency devices for embedded flash memory devices, it is necessary to make contact holes (Contact) in the pre-metal dielectric (PMD) to provide electrical channels between the active region and the first metal layer. [0003] Such as figure 1 As shown, the existing contact hole manufacturing process is: after completing the metal contact (silicide) process in the active region, silicon oxide (APM), silicon nitride (SiN), boron Phosphosilicate Glass (BPSG), Atmospheric Pressure Silicon Oxide (TEOS) and Top Silicon Oxynitride (SiON, or DARC). Then apply photoresist (PR), expose the mask to make patterns, and finally perform plasma dry etching. For all device processes,...

AI Technical Summary

Problems solved by technology

[0007] The technical problem to be solved by the present invention is to provide an etching method for the contact hole of the suspended etching barrier layer in an embedded flash memory device, which solves the problem of the metal on the top of the polycrystalline gate and the active region caused by the lack of an etching barrier layer. contact silicide excess loss

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