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The fabrication and evaluation of silicon micromechanical resonators using neutral beam etching (NBE) technology is presented. An etching technique based on a low energy neutral beam of Cl2/F2/O2 is introduced for making nano-trench patterns on 5 µm-thick silicon. The NBE technology has been investigated to form a highly-anisotropic etching shape. A 5 μm-deep trench pattern having smooth side walls with a gap width of 230 nm is achieved by using NBE. Additionally, a fabrication method for silicon resonators using NBE technology is proposed. The resonant frequency of the fabricated devices with a length of 500 μm, width of 440 μm and thickness of 5 μm is 9.66 MHz, and the average quality factor (Q) value is around 78 000. The devices fabricated by both deep reactive ion etching (DRIE) and NBE are evaluated and compared. The devices fabricated by NBE show that the motional resistances are reduced by almost 11 times from 645 kΩ to 59 kΩ and their output signals (insertion loss) are increased by approximately 15 dB in comparison with those fabricated by DRIE. Especially, devices fabricated by NBE provide the higher Q factors (average Q factor value of around 78 000) than those (average Q factor value of around 61 000) fabricated by DRIE in the same resonator parameters and measurement conditions.

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We describe a multi-diamond-wire saw for cutting monocrystalline silicon bricks into thin (120 µm) and thick (200 µm) wafers and label as freshand worn-wire sides. While almost no difference was found in the fracture stress of the thick (200 µm) wafers cut from either side, the thin (120 µm) wafers showed a lower fracture stress in those from the fresh-wire side compared to the worn-wire side. This is a remarkable result when wafers are sawn with conventional diamond wire. On the contrary, wafers sawn with improved diamond wire (100d-M6/12) showed a higher fracture stress compared to those cut with conventional diamond wire (100d-M8/16), for both the fresh-and worn-wire sides. Observing the subsurface areas of wafers by micro-Raman spectroscopy, we succeeded in quantifying the defective silicon fraction as the Raman crystallinity factor (Φ c ). We found that wafers having a higher fracture strength had a larger Φ c .