| 摘要 |
The present publication discloses a method for forming cavities in prefabricated silicon wafers comprising a first silicon layer ( 1 ), a second monocrystalline silicon layer, or a so-called structural layer ( 3 ), oriented substantially parallel with said first silicon layer ( 1 ) and an insulating layer ( 2 ) situated between said first and second layers ( 1, 3 ). According to the method, in at least one of the conducting silicon layers ( 1, 3 ) are fabricated windows ( 4 ) extending through the thickness of the layer, and cavities are etched in the insulating layer ( 2 ) by means of etchants passed to the layer via said fabricated windows ( 4 ). According to the invention, subsequent to the fabrication step of the windows ( 4 ) and prior to the etching step, a thin porous layer ( 5 ) is formed on the surface to be processed such that the etchants can be passed through said porous layer into said cavities ( 6 ) being etched and, after the cavities ( 6 ) are etched ready, at least one supplementary layer ( 7 ) is deposited in order to render to the material of said porous layer impermeable to gases. |
