Method of anisotropic etching of substrates

Abstract

A method of plasma etching of silicon that utilizes the plasma to provide laterally defined recess structures through a mask. The method is based on the variation of the plasma parameters to provide a well-controlled anisotropic etch, while achieving a very high etch rate, and a high selectivity with respect to a mask. A mixed gas is introduced into the vacuum chamber after the chamber is evacuated, and plasma is generated within the chamber. The substrate's surface is exposed to the plasma. Power sources are used for formation of the plasma discharge. An integrated control system is used to modulate the plasma discharge power and substrate polarization voltage levels.

Description

[0001] 1. Field of the Invention

[0002] The invention relates to a method of anisotropic plasma etching of substrates preferably defined with an etching mask in which the etch rate and selectivity is increased. The method can be well implemented for manufacturing microelectromechanical system (MEMS), as well as microelectronic devices.

[0003] 2. Background of the Related Art

[0004] Anisotropic plasma etching, particularly for single crystal silicon, can work independent of crystal orientation of the substrate or doping level. This method also applies to doped or undoped polysilicon. Preferred fields of applications are MEMS technology, where structures have a high aspect ratio, i.e., a high structural height to width ratio. Other examples include surface wave technology, where narrow grooves and vertical walls are etched to produce actuators, surface wave filters, delay lines, etc. Additional microelectronics applications include storage cells, insulation, collector contacts, etc.[0005...

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