摘要 |
This invention relates to a method of forming a landing pad on a semiconductor wafer comprising a silicon substrate, a dielectric layer, a passivation layer and a photo-resist layer. The photo-resist layer comprises a hole penetrating to the surface of the passivation layer which defines the position of the landing pad. An anisotropic etching through the hole is performed to vertically remove the passivation layer and a predetermined thickness of the dielectric layer under the hole to form a recess, and then the photo-resist layer is removed. A filling layer is deposited on the passivation layer and the recess. An etch-back process is performed to remove the filling layer on the bottom portion of the recess and form a circular spacer on the surrounding portion of the recess. Another anisotropic etching is performed to vertically remove the dielectric layer under the recess and down to the surface of the silicon substrate which forms a plug hole, over which the circular spacer is used as a hard mask. Lastly, a conductive layer is deposited to completely fill the recess and the plug hole which forms the landing pad.
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