Silicon Nozzle Substrate Etching for Stable Ink Discharge

The patent transitions from symmetric two-stage vertical holes to an asymmetric structure combining a tapered hole (with gradual diameter reduction) and a vertical hole. This asymmetric design eliminates the abrupt level difference between stages, preventing ink turbulence and stagnation while maintaining manufacturing precision through controlled etching processes.

The patent introduces a tapered hole with curved transitional geometry instead of sharp angular transitions. The gradual diameter reduction creates a smooth curved profile that guides ink flow continuously, eliminating the abrupt level differences that cause turbulence and stagnation in straight vertical hole configurations.

The patent changes the etching parameters and methodology from traditional anisotropic etching to metal-assisted chemical etching (MACE). This parameter change enables the formation of ideal conical holes with precise control over the taper angle, overcoming the limitations of single crystal silicon brittleness and the inability to form smooth curved surfaces with conventional etching methods.

The patent introduces a metal catalyst as an intermediary in the etching process. This metal layer mediates the chemical etching of single crystal silicon, enabling the formation of conical holes with smooth curved surfaces that would be impossible to achieve through direct mechanical or conventional chemical etching of the brittle silicon material alone.