Mitsubishi Denki Kabushiki Kaisha

Patrick James French

Kazuhiko Tsutsumi

Hiroshi Ohji

Shinichi Izuo

An electrochemical etching system has an etching bath for holding an n-type silicon substrate with a first surface of the substrate in contact with hydrofluoric acid, an electrode positioned in the hydrofluoric acid, a power source having a positive pole connected to the silicon substrate and a negative pole connected to the electrode, and an illumination unit having a light source for illumination of a second surface of the silicon substrate. The illumination unit illuminates the second surface of the silicon substrate with an illumination intensity of 10 m W/cm or more. A ratio of a maximum illumination to a minimum illumination of the second surface of the silicon substrate is 1.69:1 or less. With the etching system, pores and/or trenches of a certain size and shape can be formed in an entire area of the silicon substrate having a diameter of more than three inches.

Method and apparatus for radiation assisted electrochemical etching and etched product

A method of manufacturing a silicon device with a single crystal structure, including forming etching start patterns on a surface of a silicon substrate; etching the silicon substrate by applying a voltage to the silicon substrate while the silicon substrate is immersed in a solution containing fluorine ions, with the silicon substrate used a positive electrode, to form narrow etched portions that extend into the substrate from the etching start patterns; and accelerating etching of the silicon substrate by increasing current flowing through the silicon substrate after the narrow etched portions have reached a predetermined depth, so that neighboring etched portions are in communication with each other below the narrow etched portions and a free standing structure including part of the silicon substrate is formed, and a hollow portion is formed below the free standing structure.

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Delft, Netherlands

Patrick James French