In the scanning probe microscopy-based microplasma etching system proposed by our group, the microcantilever probe integrated with microplasma device is a multilayered structure. However, the thin film residual stress generated by microfabrication process may cause undesirable bending deformation of the cantilever. In order to predict and minimize the stress-induced deformation in the cantilever design, we experimentally measure and calculate each thin film stress of the cantilever based on Stoney equation. Then the stress-induced bending deformation of the cantilever is simulated by finite element simulation. By adjusting the thickness of reserved silicon layer of the cantilever, the deflection can be minimized to <5 μm for a 750 μm-length cantilever. Finally the microcantilever probes with different thickness of reserved silicon layer are successfully fabricated by MEMS process. The bending deformation of actual fabricated cantilevers agree well with simulation results, which verifies the feasibility of the cantilever structural design. The results of this paper may lay a foundation for further scanning plasma maskless etching.

A novel maskless microplasma etching method based on parallel scanning probe microscopy is presented in this paper. The advantages of proposed etching system are high etching rate, high fidelity, simple-structure, and flexible to fabricate various material. The SiO2 cantilever probe with microplasma reactor and nano-aperture at the hollow tip is designed and successfully fabricated with good quality. Experiment results show that the devices can discharge stably in SF6 gas. The voltages–current (V–I) curves exhibit negative differential resistance of about 0.5 MΩ in a classical hollow cathode discharge mode. The pd scaling values (p and d are the SF6 gas pressure and characteristic dimension of the microdischarge devices, respectively) for minimum ignition voltage are observed about 0.3–0.4 Pa m. Active F atom lines can be obviously found from the optical emission spectroscopy of microdischarge devices in SF6 gas. A two-dimensional fluid model is used to simulate the dispersion distance and etching rate of silicon when the microplasmas are ejected through the nano-aperture. The experiment and simulation results verify the feasibility of the ongoing experiments of silicon maskless etching.