Tohoku University

Tomotsugu Ohashi

Tadahiro Ohmi

Kazuhiro Yoshikawa

Teppei Uchimura

Kazuki Soeda

Shigetoshi Sugawa

Tatsuro Yoshida

Tetsuro Yoshida

A method of etching capable of rapidly and flatly performing wet etching on a Si substrate using fluonitric acid represented by HF(a)HNO(b)HO(c) (where the unit of a, b and c is wt % and a+b+c=100). The etching rate of an SiOlayer with the highly concentrated fluonitric acid is significantly lowered by the appropriate selection of its composition as compared with the etching rate of the Si substrate, and etch the Si substrate until the SiOlayer is exposed. In this way, it is possible to rapidly etch the Si substrate and significantly enhance the flatness of the etched surface.

[object Object]

There is provided with an etching method using an etching apparatus. Four arms can be positioned in a direction substantially from a center of the stage toward a peripheral portion with an angle difference of about 90&#xb0;. Etchant is supplied to a first position nearest to the center of the object which is rotating, from a first etchant supply nozzle placed on a first arm. Etchant is further supplied to a second position second nearest to the center of the object, from a second etchant supply nozzle placed on a second arm. The second arm is substantially symmetrically positioned with respect to the first arm and the second arm has an angle difference of about 180&#xb0; with respect to the first arm.

Ultra high-speed wet etching apparatus

Growing community of inventors

Singapore, Singapore

Tomotsugu Ohashi