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US 7,732,340 B2Granted
Method for adjusting a critical dimension in a high aspect ratio feature
AssigneeTokyo Electron Limited
InventorsToshifumi Nagaiwa, Junichi Sasaki, Stefan Sawusch
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Abstract
A method for adjusting the lateral critical dimension (i.e., length and width) of a feature formed in a layer on a substrate using a dry etching process. One or more thin intermediate sub-layers are inserted in the layer within which the feature is to be formed. Once an intermediate sub-layer is reached during the etching process, an etch process is performed to correct and/or adjust the lateral critical dimensions before etching through the intermediate sub-layer and continuing the layer etch.
Claims16
A method of etching a substrate, comprising:
- forming a film stack on said substrate, said film stack comprising a composite layer having an upper material layer, an intermediate sub-layer and a lower material layer, and a mask layer overlying said composite layer having a pattern formed therein;
- and
- transferring said pattern to said composite layer using one or more etching processes by:
- transferring said pattern to said upper material layer of said composite layer until said intermediate sub-layer is reached,
- adjusting at least one critical dimension (CD) of said pattern in said upper material layer,
- transferring the adjusted pattern in said upper material layer to said intermediate sub-layer, and
- transferring the adjusted pattern to said lower material layer of said composite layer,
- wherein said pattern comprises a rectangular pattern characterized by a first CD along a major axis of said pattern and second CD along a minor axis of said pattern, and
- wherein said adjusting comprises adjusting a ratio of said first CD to said second CD in said upper material layer of said composite layer such that said adjusted ratio in said upper material layer of said composite layer is substantially the same as an initial ratio of said first CD to said second CD in said mask layer.
6 more elements
A method of etching a substrate, comprising:
- forming a film stack on said substrate, said film stack comprising a composite layer having an upper material layer, an intermediate sub-layer and a lower material layer, and a mask layer overlying said composite layer having a pattern formed therein;
- and
- transferring said pattern to said composite layer using one or more etching processes by;
- transferring said pattern to said upper material layer of said composite layer until said intermediate sub-layer is reached,
- adjusting at least one critical dimension (CD) of said pattern in said upper material layer,
- transferring the adjusted pattern in said upper material layer to said intermediate sub-layer, and
- transferring the adjusted pattern to said lower material layer of said composite layer,
- wherein said transferring said pattern to said composite layer comprises transferring said pattern to said composite layer having a second intermediate layer below said lower material layer and a second lower material layer below said second intermediate layer, said transferring further comprising:
- adjusting at least one critical dimension (CD) of said pattern in said lower material layer,
- transferring the adjusted pattern in said lower material layer to said second intermediate sub-layer, and
- transferring the adjusted pattern in said lower material layer to said second lower material layer of said composite layer.
8 more elements
A method of etching a substrate, comprising:
- forming a film stack on said substrate, said film stack comprising a composite layer having an upper material layer, an intermediate sub-layer and a lower material layer, and a mask layer overlying said composite layer having a pattern formed therein;
- and
- transferring said pattern to said composite layer using one or more etching processes by;
- transferring said pattern to said upper material layer of said composite layer until said intermediate sub-layer is reached,
- adjusting at least one critical dimension (CD) of said pattern in said upper material layer,
- transferring the adjusted pattern in said upper material layer to said intermediate sub-layer, and
- transferring the adjusted pattern in said lower material layer to said composite layer,
- wherein said forming comprises forming a composite layer having an intermediate sub-layer of substantially different material composition than said upper material layer and said lower material layer, and
- wherein said intermediate sub-layer comprises silicon nitride (SixNy) and said upper material layer and said lower material layer comprises silicon oxide (SiOz), wherein atomic subscripts x, y, and z are integers having a value grater than or equal to unity.
6 more elements
Dependencies are inferred from the claim text.