Planarization etchback method after groove is filled with medium

Abstract

The invention provides a planarization etchback method after a groove is filled with a medium, which comprises the following specific steps of: filling a double-layer dielectric in the groove on the surface of a silicon substrate, forming a first dielectric layer and a second dielectric layer on the surface of the silicon substrate from top to bottom, and coating photoresist on the first dielectric layer for the first time; etching the photoresist and the first dielectric layer, completely etching the photoresist on the surface of the silicon substrate after etching, wherein the first dielectric layer with a certain height is left on the top of the groove in the surface of the silicon substrate; after the treatment, carrying out photoresist coating on the second dielectric layer on the surface of the silicon substrate for the second time; adjusting the selection ratio of the photoresist to the first medium and the second medium, completely etching the second medium layer, the photoresist coated for the second time and the remaining first medium layer at the same time. By means of the planarization back-etching method, the flatness of the surface of the groove in the silicon substrate after medium etching can be remarkably improved, the machining quality is improved, and subsequent process defects are reduced.

Description

technical field [0001] The invention belongs to the technical field of semiconductors, in particular to a method for planarizing and etching back after a trench is filled with a medium. Background technique [0002] At present, deep trench structure devices are widely used in semiconductor technology, such as electronic devices that use deep trench structures for electrical insulation, and power MOSFETs that use super junction technology as high-voltage switching converters, etc., are widely used in mobile communications and control circuits , Automotive electronics, etc. The unevenness of the dielectric on the trench surface will lead to increased metal contact resistance in subsequent processes, and even metal voids will affect the yield of the silicon-based surface. [0003] The traditional and existing technologies use a chemical mechanical polishing method for dielectric planarization after trench filling, which is expensive and has poor uniformity. Contents of the i...

AI Technical Summary

Problems solved by technology

The unevenness of the dielectric on the surface of the trench will lead to increased metal contact resistance in subsequent processes, and even metal voids will affect the yield of the silicon-based surface

[0003]Traditional and existing technologies use chemical mechanical polishing for dielectric planarization after trench filling. This method is expensive and has poor uniformity

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