| 摘要 |
A method for forming a contact hole having a stepped sidewall is disclosed. First, a capping layer is formed on a semiconductor substrate, and then, a first dielectric layer and a second dielectric layer having different etch rates are formed on the capping layer. A preliminary contact hole is anisotropically etched through the layers, and part of the way through the substrate. After this, the sidewalls of the preliminary contact hole are isotropically etched with an etching agent having a higher etch rate for the second dielectric layer than for the first dielectric layer, thereby forming a step sidewall. Finally, the exposed portions of the capping layer are removed to complete the contact hole fabrication.
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