Method for reducing harmonic distortion in comb drive devices

A method of fabricating a comb drive device utilizing one or more sacrificial etch-buffers, comprising the steps of:

• providing a wafer substrate having a first surface and a second surface;
• applying a first epitaxial layer onto the first surface of the wafer substrate;
• etching a pattern into the first epitaxial layer and at least a portion of the wafer substrate to form one or more comb drive structures with one or more sacrificial etch-buffers therebetween;
• liberating one or more of the sacrificial etch-buffers from the comb drive structure with a selective etch;
• bonding the etched wafer substrate to an underlying support substrate;
• and etching away the wafer substrate.

A method of fabricating a comb drive device utilizing one or more sacrificial etch-buffers, comprising the steps of:

• providing a wafer substrate having a first surface and a second surface;
• applying a first epitaxial layer onto the first surface of the wafer substrate;
• applying a cap layer onto the first epitaxial layer, said cap layer defining a pattern of a microstructure including at least one sacrificial etch-buffer;
• etching the first epitaxial layer and at least a portion of the wafer substrate to form the microstructure with one or more sacrificial etch-buffers;
• removing the cap layer from the first epitaxial layer;
• liberating one or more of the sacrificial etch-buffers from the microstructure with a selective etch process;
• bonding the etched wafer substrate to an underlying support substrate;
• and etching away the wafer substrate.

A method of fabricating a comb drive device utilizing one or more sacrificial etch-buffers, comprising the steps of:

• providing a wafer substrate having a first surface and a second surface;
• applying a first epitaxial layer onto the first surface of the wafer substrate;
• etching a pattern into the first epitaxial layer and at least a portion of the wafer substrate to form one or more comb drive structures with one or more sacrificial etch-buffers therebetween;
• liberating one or more of the sacrificial etch-buffers from the comb drive structure with a selective etch process;
• acoustically removing the liberated etch-buffers;
• bonding the etched wafer substrate to an underlying support substrate;
• etching away the wafer substrate;
• and acoustically removing one or more of the liberated etch-buffers, if any.

A method of fabricating a comb drive device utilizing one or more sacrificial etch-buffers, comprising the steps of:

• providing a wafer substrate having a first surface and a second surface;
• applying a first epitaxial layer onto the first surface of the wafer substrate;
• applying a second epitaxial layer onto the second surface of the wafer substrate;
• etching a pattern into the first epitaxial layer and at least a portion of the wafer substrate to form one or more comb drive structures with one or more sacrificial etch-buffers therebetween;
• liberating one or more of the small sacrificial etch-buffers from the comb drive structure with a selective etch process;
• bonding the etched wafer substrate to an underlying support substrate;
• and etching away the wafer substrate.

A method of fabricating a comb drive device utilizing one or more sacrificial etch-buffers, comprising the steps of:

• providing a wafer substrate having a first surface and a second surface;
• applying a first epitaxial layer onto the first surface of the wafer substrate;
• etching a pattern into the first epitaxial layer and at least a portion of the wafer substrate to form one or more comb drive structures with one or more sacrificial etch-buffers therebetween;
• bonding the etched wafer substrate to an underlying support substrate;
• and etching away the wafer substrate, thereby liberating said one or more of the sacrificial etch-buffers from the wafer substrate.