Through hole etching method

Abstract

The invention discloses a through hole etching method which etches a through hole after a through hole etching structure is formed; when a bottom anti-reflection coating in the through hole etching structure is etched, hydrogen bromide gas is adopted for etch to obtain a tapered hole structure. The through hole etching method can enable the characteristic dimension of the etched through hole to reach the required characteristic dimension of the through hole without changing the traditional exposure and developing method.

Description

technical field [0001] The invention relates to the technical field of semiconductor manufacturing, in particular to a through hole etching method. Background technique [0002] Vias play an important role in the composition of device structures as the interconnection between multilayer metal layers and the connection between the active area of ​​the device and the external circuit. In order to ensure the stability of the device operation, the through hole filled with conductive material is required to have good conductive characteristics, that is, the smaller the resistance value, the better, which makes it very important to strictly control the through hole etching process. [0003] With the increasing density of devices and complexity of processes, higher requirements are placed on the via etching process. The traditional via hole etching method uses an etching process to etch the stop layer (stop layer) once, which causes great damage to the via hole. With the developme...

AI Technical Summary

Problems solved by technology

[0015] The currently etched via hole feature size is determined by the via hole size reserved by the patterned photoresist layer 70, such as Figure 1b As shown, as the size of the device decreases, the feature size of the via hole will also decrease, so when the photoresist layer 70 is patterned, using the existing exposure and development methods will result in reserved The via size is larger than the preset via feature size

For example, if figure 2 As shown, the set characteristic size of the through hole is 10 nanometers or 9 nanometers, but due to the limitations of the existing exposure and development methods, after patterning the photoresist layer 70, only 11 nanometers can be reserved. Hole size

In this way, the via hole feature size cannot be reduced without changing the existing exposure and development method, but changing the existing exposure and development method will increase the cost

Images