Batch Fabrication of Silicon Nanometer Tip Using Isotropic Inductively Coupled Plasma Etching

Abstract

This work reports a batch fabrication process for silicon nanometer tip based on isotropic inductively coupled plasma (ICP) etching technology. The silicon tips with nanometer apex and small surface roughness are produced at wafer-level with good etching homogeneity and repeatability. An ICP etching routine is developed to make silicon tips with apex radius less than 5 nm, aspect ratio greater than 5 at a tip height of 200 nm, and tip height more than 10 μm, and high fabrication yield is achieved by mask compensation and precisely controlling lateral etch depth, which is significant for large-scale manufacturing.

Batch Fabrication of Wear-Resistant and Conductive Probe with PtSi Tip

“…In ICP isotropic dry etching, large exposure ratio leads to severe edge effects. The etching rate is faster at the edge than in the center, which cannot be fully compensated by mask compensation [36]. After mask compensation, the remaining neck width of the tip post after etching was still in the range of 490 nm to 555 nm, as shown in Figure 3.…”

“…Batch fabrication of Si nano-tips with good wafer level uniformity is technically challenging. Dependence of the etched tip profile on ICP isotropic etching parameters such as chamber pressure, gas flow rate, and lower electrode power were systematically investigated [36]. The ICP etching was optimized to reduce the roughness of the tip post.…”

“…Figure 2 shows the tip profiles etched in different chamber pressures, where the tip surface roughness was reduced as the chamber pressure increased. In SF 6 -based ICP isotropic etching of Si, the density of fluorine radicals determines the etch rate and the shape of the tip post [36], and depends on ICP power, SF 6 gas flow rate, and chamber pressure. The chamber pressure not only affects the density of fluorine radicals, but also affects its mean free path [37].…”

Xenon Difluoride Dry Etching for the Microfabrication of Solid Microneedles as a Potential Strategy in Transdermal Drug Delivery

“…Isotropic inductively coupled plasma etching using SF 6 , for instance, was shown to be effective in creating MN arrays. [ 34 ] If not optimized efficiently, isotropic etching alone may result in shorter MN arrays. Employing isotropic etching with SF 6 alone resulted in a MN array with a maximum height of ≈120 µm.…”

The Reflectance Characteristics of an Inverse Moth-Eye Structure in a Silicon Substrate Depending on SF6/O2 Plasma Etching Conditions

“…However, this process is difficult to apply to nanostructures due to the orientation dependence of alkaline etching in silicon wafers and its limitations in selecting other materials for photovoltaic devices. Conversely, plasma etching for moth-eye-inspired structures can be applied to various substrates, and the slope of the microstructure can be controlled using the process parameters [ 25 , 26 , 27 ]. Moreover, nanostructures can be formed using plasma etching; thus, they can be applied to various devices, such as photodetectors, LED devices, and solar cells [ 28 ].…”