Etching method for inclined hole

Abstract

The invention provides an etching method for an inclined hole. The etching method comprises the following steps: introducing etching gas into a reaction chamber and starting an excitation power supply and a bias power supply so as to realize etching of the inclined hole in a to-be-etched surface of a silicon chip, wherein the etching gas comprises SF6 and O2, and the gas flow ratio of SF6 to O2, process pressure, excitation power and bias power are such arranged that ideal etching morphology of the inclined hole can be obtained by increasing the gas flow ratio of SF6 to O2, process pressure, excitation power and bias power. The etching method for the inclined hole in the invention can obtain ideal etching morphology of the inclined hole, i.e., an inclination angle is in a range of 80 to 88 DEG, a sidewall is smooth, and linewidth loss does not exist; the etching rate is increased; and requirements of TSV technology are met and process efficiency is improved.

Description

technical field [0001] The invention relates to the technical field of microelectronics, in particular to an oblique hole etching method. Background technique [0002] With MEMS devices and MEMS systems being more and more widely used in automotive and consumer electronics fields, and TSV through hole etching (ThroughSiliconEtch) technology has broad prospects in the future packaging field, dry plasma deep silicon etching process has gradually become One of the hottest processes in the field of MEMS processing and TSV technology. The etching process of oblique holes is currently an important means to achieve TSV and packaging fields. This is because: for straight holes, especially straight holes with a certain depth-to-width ratio, it will increase the difficulty of PVD filling in the subsequent channel. And the oblique hole (the inclination angle is about 85°) is more conducive to the PVD filling in the back channel. [0003] The existing oblique hole etching method is to...

AI Technical Summary

Problems solved by technology

[0004] First, the inclination angle of the oblique hole obtained by using the existing oblique hole etching method is about 60°, which cannot meet the requirements of certain processes. For example, in the field of 3D-IC, the inclination angle of the oblique hole is usually required to be between 80° around 88°

[0005] Second, 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

[0006] Third, due to the limitation of the opening size and the obstruction of the mask, the gas flow will form a flow field static area at the top of the inclined hole, which will cause the gas to stay at the top of the inclined hole for too long, resulting in serious isotropic etching of the top, which in turn will There is a large line width loss at the top of the inclined hole, for example, the original line width of 10 μm will increase to 20-30 μm due to isotropic etching

Images