| 摘要 |
Methods herein can be used for removing silicon nitride around fins and other structures without damaging underlying silicon structures. Methods herein also include forming dual layer spacers and L-shaped spacers, as well as other configurations. Techniques include a multi-step process of anisotropic etching of low-k material with high selectivity to silicon nitride, followed by isotropic etching of SiN with high selectivity to the low-k material. Such techniques, for example, can be used to form an L-shaped spacer on a 3-D gate structure, as well as providing a method for completely removing silicon nitride without damaging surrounding or underlying materials. |
