| 摘要 |
Provided is a method for removing etch byproducts inside a contact hole while minimizing lateral etching of the contact hole. After an etching process, a wafer having a contact hole is placed inside a plasma reaction chamber. The contact hole contains etch byproducts that may degrade the quality of electrical connections. A radio frequency (RF) source creates a RF field inside the reaction chamber. A gas mixture containing chemicals that are reactive with the etch byproducts is introduced into the reaction chamber. The gas mixture becomes ionized by the RF field and reacts with the etch byproducts in the contact hole, removing the etch byproducts. The gas mixture may include approximately 10-60 vol. % hydrogen gas, a gas that reacts with the etch byproducts (e.g., NF3), and nitrogen. The hydrogen gas at least significantly reduces lateral etching of the contact hole by the reactive gas.
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