Patent ID: 7485238

Claim:
An etching method for etching away different surfaces of a work piece to etch the work piece into a predetermined shape, the etching method comprising: thinning one portion of at least one surface of the work piece; applying only a single mask layer to each different surface of the work piece to be etched away without applying a mask layer to any thinned portion thinned by said thinning such that the thinned portion is formed as a through hole, wherein each applied mask layer is made from the same material, and wherein a thickness of the applied mask layer is smaller on a surface of the work piece which requires a greater etching amount than a thickness of each mask layer applied to each other surface of the work piece determined to require a smaller etching amount; and etching away each applied mask layer using different etching amounts based on respective degrees of etching amounts of the applied mask layers and etching away the different surfaces of the work piece to form the work piece into a predetermined thickness, wherein after carrying out said etching away of each applied mask layer using different etching amounts based on respective degrees of etching amounts of the applied mask layers, uniformly etching virtually an entire portion of the work piece without the applied mask layers so as to make the entire portion of the work piece thinner.