Flattening method for surface

Abstract

Abstract PURPOSE:To obtain a preferably flat surface over a whole wafer even when the wafer has a large bore diameter by depositing a silicon film on an SiO2 formed with an uneven part on its surface in thickness of the stepwise difference of the uneven part on the SiO2, selectively polishing the silicon film, and etching the SiO2 and the silicon at an equal velocity. CONSTITUTION:A device layer 2 is formed on a silicon substrate 1, and an SiO2 3 which becomes a device protecting and interlayer insulating film is formed thereon. Since the surface of the device layer becomes an uneven shape, the upper surface of the SiO2 3 becomes uneven shape by reflecting it. A silicon film 4 is formed by an LPCVD method on the SiO2 3. When the film 4 is selectively polished, the bumps of the SiO2 3 become stoppers, thereby automatically stopping the polishing, the silicon film remains on the recesses of the SiO2 so that the surface becomes flat. This selective polishing is conducted by securing the wafer to a supporting plate with wax, with polyester polishing pad and ethylenediamine.pyrocatechol aqueous solution. Then, dry etching for equalizing the etching velocity for the silicon and the SiO2 is conducted.

Inventors

• 👤 Hiroshi Terao
• 👤 博 寺尾

Bibliographic Details