Abstract. Microsystem technology is well suited to batch fabricate microhemispherical resonator gyroscopes (HRG) to reduce cost and volume. In the processing of micro-HRG, a crucial step is to get a 3-D hemispherical mold with the large-scale, high-symmetry, and smooth surface. Compared with the hemispherical resonator, the toroidal resonator has the smaller frequency split and larger effective resonance mass under the same processing accuracy. A wafer-scale etching method for the toroidal resonator mold was presented, which is based on the deep reactive ion etching and improved HNA isotropic etching. The advantages of this method include low cost, time savings, and easy operation. With this method, toroidal molds with an average diameter over 1900  μm, asymmetry <0.2  %  , and roughness <10  nm were successfully fabricated. The uniformity and surface smoothness of the molds are mainly determined by the parameters of HNA etching. A series of controlled experiments were conducted to optimize isotropic etching parameters that include mask design, bath agitation, HNA composition, and temperature. The influence of these parameters on etching rate and uniformity was discussed. The result shows that the composition of 2.5:7:1 (HF  :  HNO3  :  CH3COOH), temperature of 30°C, and bath agitation of 20 revolutions per minute are optimal etching conditions to achieve high-performance molds.

中文翻译：

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改进的 HNA 各向同性蚀刻用于具有 <10 nm 粗糙度的大型高度对称环形硅模具

摘要。微系统技术非常适合批量制造微半球谐振陀螺仪 (HRG)，以降低成本和体积。在微型HRG的加工中，关键的一步是获得具有大尺寸、高对称性和光滑表面的3D半球形模具。与半球形谐振器相比，在相同加工精度下，环形谐振器具有更小的分频和更大的有效谐振质量。提出了一种基于深反应离子刻蚀和改进的HNA各向同性刻蚀的环形谐振腔模具晶圆级刻蚀方法。这种方法的优点包括成本低、节省时间和易于操作。采用这种方法，成功制造了平均直径超过 1900 μm、不对称性 <0.2 % 和粗糙度 <10 nm 的环形模具。模具的均匀性和表面光洁度主要由海航蚀刻的参数决定。进行了一系列受控实验以优化各向同性蚀刻参数，包括掩模设计、浴搅拌、HNA 成分和温度。讨论了这些参数对蚀刻速率和均匀性的影响。结果表明，2.5:7:1 (HF: HNO3: CH3COOH) 的组成、30°C 的温度和每分钟 20 转的浴槽搅拌是实现高性能模具的最佳蚀刻条件。讨论了这些参数对蚀刻速率和均匀性的影响。结果表明，2.5:7:1 (HF: HNO3: CH3COOH) 的组成、30°C 的温度和每分钟 20 转的浴槽搅拌是实现高性能模具的最佳蚀刻条件。讨论了这些参数对蚀刻速率和均匀性的影响。结果表明，2.5:7:1 (HF: HNO3: CH3COOH) 的组成、30°C 的温度和每分钟 20 转的浴槽搅拌是实现高性能模具的最佳蚀刻条件。