Denso Corporation

Nippondenso Co., Ltd.

Yoshitsugu Abe

Hiroshi Tanaka

Tsuyoshi Fukada

Motoki Ito

Yasutoshi Suzuki

Minekazu Sakai

Hiroshi Okada

Kazuhisa Ikeda

Koki Mizuno

Kazuyuki Inoue

Toshihisa Taniguchi

Yukihiko Tanizawa

Atsushi Sakaida

Satoru Kosaka

Koji Matsumoto

After an Si wafer is anisotropically etched through an etching mask having an opening in an anisotropically etching solution, an etching face of the Si wafer emerged by the anisotropic etching is subjected to anodic oxidation by applying a positive voltage for anodic oxidation on the Si wafer. As a result, the etching face of the Si wafer is isotropically etched due to the anodic oxidation in the anisotropic etching solution. By the isotropic etching thus performed, a sharp corner formed at an end portion of a recess portion formed in the Si wafer by the anisotropic etching, is rounded. Because the isotropic etching reaction progresses very slowly in comparison with the anisotropic etching, control of the etching can be made easy and accurately. As a result, the thickness of the diaphragm can be prevented from being dispersed.

Method of etching silicon wafer and silicon wafer

An etching method for a silicon substrate, which can easily smooth the etching surface of the (110)-oriented silicon, is disclosed. A container is filled with KOH solution. In the KOH solution is immersed a (110)-oriented silicon wafer having a PN junction and is also disposed a platinum electrode plate to face the silicon wafer. To between a platinum electrode of the silicon wafer and the platinum electrode plate are connected a constant voltage power source, an ammeter and a contact in series. A controller starts etching from one surface on which the PN junction is formed, and terminates voltage application when the specified time lapses after the formation of an anodic oxide film is equilibrated with the etching of the anodic oxide film on the etching surface on the PN junction part. In this case, the controller detects flowing current through the ammeter, and the point of time when the equilibrium state is obtained is the point of inflection of the detected current to the constant current after the peak thereof.

Electrochemical etching method for silicon substrate having PN junction

A silicon substance is etched by using alkaline etchant containing additive (Cu, Pb, Mg). The content of the additive is controlled intentionally to provide desired etching quality during an etching operation.

Etchant, etching method using the same, and related etching apparatus

Etching method for silicon substrates and semiconductor sensor

In a fine processing method for forming a silicon substrate, first, an oxynitride layer is formed on the silicon substrate. Thereafter, a silicon nitride layer is formed on the oxynitride layer and patterned into a predetermined shape to cause it to function as an etching mask. The silicon substrate is etched through the etching mask. In this case, because of the oxynitride layer formed between the silicon substrate and the silicon nitride layer, an interface between the silicon substrate and the silicon nitride layer is not easily eroded in the etching process. As a result, processing accuracy of the substrate is improved.

Fine processing method

Growing community of inventors

Anjo, Japan

Yoshitsugu Abe