Method of etching an opening

US6620331B1 · kind B1 · utility

Inventors

• Thomas Laurell · Lund, SE
• Johan Drott · Bjärred, SE
• Johan Nilsson · Höllviken, SE
• Lars Wallman · Sjöbo, SE

Key dates

• Filing date: Jan 9, 2001
• Grant date: Sep 16, 2003
• Expiry date: Jan 9, 2021

Classification

• Technology area (CPC H): Electricity
• CPC primary: H01L21/30608
• WIPO field: Textile and paper machines
• WIPO sector: Mechanical engineering

Abstract

The invention relates to a method for etching an opening, and more precisely, to etching in a silicon plate for creating a nozzle opening. According to the invention, one side of the silicon plate (1) is protected by a protective layer (2), and a recess (5) is made in the protective layer. Etching is made anisotropically through the recess so as to create a cavity (4) in the shape of a truncated pyramid of a predetermined depth in the silicon plate. The cavity is doped so as to create a doped layer (3) at the predetermined depth. The etching is then continued until the bottom surface of the cavity has passed the doped layer. Subsequently, etching is performed from the other side, while a voltage is applied to the doped layer, so as to free the nozzle opening at the other side. The invention enables an accurate control of the surface area of the nozzle opening. Through this, the amount of discharged fluid and the directional precision can be controlled very accurately.