Plasma etching method and system

Abstract

The invention provides a plasma etching method and a system. The etching method comprises a plurality of etching cycles, wherein each etching cycle comprises a plasma etching stage and a charge neutralization stage; partial charge is attached on the surface of a substrate and / or in an etching graph in an etching process; plasma etching is stopped in the charge neutralization stages; ions with preset conductive charge are supplied into a reaction chamber within at least partial time period in a plasma etching stop process; and the ions with the preset conductive charge are used for neutralizing the charge attached on the surface of the substrate and / or in the etching graph. An influence of a built-in electric field generated by deposited charge on plasma is eliminated by charge neutralization; the accuracy of the plasma etching is ensured; and the collimation of the etching graph is ensured.

Description

technical field [0001] The invention relates to the field of semiconductor manufacturing technology, in particular to a plasma etching method and system. Background technique [0002] There are two basic etching processes in semiconductor manufacturing: dry etching and wet etching. Among them, dry etching is to expose the surface of the silicon wafer to the plasma generated in the gaseous state. The plasma passes through the window opened in the photoresist and reacts physically or chemically with the silicon wafer, thereby removing the exposed surface material. Therefore, dry etching can also be called plasma etching. [0003] During the plasma etching process, there will be charges attached to the surface of the substrate to be etched or the inside of the etched pattern, such as figure 1 shown. These attached and accumulated charges will form a built-in electric field inside the etched pattern or on the surface of the substrate. These built-in electric fields will affec...

AI Technical Summary

Problems solved by technology

These attached and accumulated charges will form a built-in electric field inside the etched pattern or on the surface of the substrate. These built-in electric fields will affect the trajectory of the plasma, resulting in twisting and bowing of the etched pattern. Especially for the etching of some high aspect ratio patterns, the charge accumulation effect will become more serious

This charge accumulation leads to misalignment of etched patterns, which affects the performance of semiconductor devices

Images