Method and apparatus for micromachining using a magnetic field and plasma etching

A method of forming a fabricated device, comprising:

• providing a contoured workpiece;
• generating a stable plasma, said plasma comprising free electrons and ions,
• said free electrons having a velocity toward said workpiece;
• generating a magnetic field at said workpiece and within said plasma;
• forming a high negative charge density region on a contoured region of said workpiece by effecting the path of travel of said free electrons with said magnetic field;
• changing the location of said high negative charge density region by changing a direction of said magnetic field while etching said workpiece with said plasma.

A method of plasma etching a material layer to form a microstructure, comprising:

• providing a material layer having at least one contour;
• flowing gas into a chamber containing said material layer;
• generating a stable etching plasma from said gas, wherein said plasma comprises free electrons and ions;
• etching said material layer with said plasma;
• and
• varying the location of said etching of said material layer during said etching by varying the location of impingement of said free electrons.

A method of forming a plasma etched device, comprising:

• providing a contoured workpiece comprising an insulating material in a plasma chamber;
• generating a stable plasma within said chamber from a gas flow, said plasma comprising free electrons and ions, said free electrons having a path of travel toward said workpiece, said ions etching said workpiece;
• generating a magnetic field at said workpiece and controlling said magnetic field in intensity and direction to vary the location of impingement of said free electrons on said workpiece, the location and impingement of said ions on said workpiece being affected by the location of impingement of free electrons on said workpiece;
• and
• applying an RF bias power to said workpiece during ion etching and adjusting, said RF bias power during etching to vary the intensity of etching.

An apparatus for plasma etching a workpiece, said apparatus comprising:

• a plasma etching chamber which includes a workpiece holder;
• a magnetic field source for generating a directional magnetic field of adjustable intensity into said chamber, at least one of said workpiece holder and magnetic field source being movable relative to the other to change the direction of said magnetic field relative to a workpiece placed on said holder;
• an adjustable RF bias source for providing an adjustable RF bias to a workpiece on said holder;
• and
• a controller capable of adjusting at least one of the magnetic field direction, the magnetic field intensity and the RF bias during an etching operation conducted within said chamber.