Slanted Groove Etching Method

Abstract

The invention provides a chute etching method. The method comprises the following steps: introducing SF6, O2 and C4F8 into a reaction chamber as etching gases, and starting an upper electrode power supply and a lower electrode power supply, so as to etch a chute on a surface of a silicon wafer to be etched, wherein the lower electrode power supply is a low frequency power supply; the setting way of the lower electrode power of the lower electrode power supply, the chamber pressure of the reaction chamber and the flow of the SF6, O2 and C4F8 is as follows: the lower electrode power, the chamber pressure and the flow of the O2 are improved, and the flow of the SF6 and C4F8 is reduced, so that the lateral wall of the chute can be straight and the etching rate can be improved.

Description

technical field [0001] The invention relates to the technical field of microelectronics, in particular to an oblique groove etching method. Background technique [0002] As MEMS devices and MEMS systems are more and more widely used in the automotive and consumer electronics fields, and TSV through hole etching (Through Silicon Etch) technology has broad prospects in the future packaging field, dry plasma deep silicon etching process It has gradually become one of the hottest processes in the field of MEMS processing and TSV technology. The etching process of silicon grooves is a common etching process. Based on different applications, the requirements for the morphology of silicon grooves are also different. For example, in the field of packaging, it is usually necessary to obtain the morphology of silicon grooves with sloped sidewalls to meet the requirements of other subsequent processes. Usually, in order to facilitate the subsequent PVD filling, the inclination angle ...

AI Technical Summary

Problems solved by technology

[0004] First, due to the large SF 6 and O 2 The flow rate ratio, that is, SF 6 The flow rate is relatively large, while O 2 The flow rate is relatively small, resulting in SF 6 The isotropic etching effect is strong, while O 2 The protection effect of the side wall is weak, so that the side wall of the obtained chute is not straight enough

[0005] Second, due to the lower chamber pressure used in the existing inclined groove etching method, the ionization rate of the gas is lower and the concentration of F ions is lower, resulting in a lower etching rate, only 9 μm / min

Also, since C 4 f 8 The addition of a large amount of , which enhances its deposition effect, further reduces the etching rate

[0006] Third, due to C 4 f 8 A large amount of addition, the self-masking effect of the CF group generated by it will make the side wall of the oblique hole rough

At the same time, the higher ion bombardment energy will also make the sidewall of the inclined hole rough

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