19-01-2017 дата публикации
Номер: US20170018439A1
Автор:
Xikun Wang,
David Cui,
Anchuan Wang,
Nitin K. Ingle,
WANG XIKUN,
CUI DAVID,
WANG ANCHUAN,
INGLE NITIN K,
Wang Xikun,
Cui David,
Wang Anchuan,
Ingle Nitin K.
Methods are described for etching metal layers that are difficult to volatize, such as cobalt, nickel, and platinum to form an etched metal layer with reduced surface roughness. The methods include pretreating the metal layer with a local plasma formed from a hydrogen-containing precursor. The pretreated metal layer is then reacted with a halogen-containing precursor to form a halogenated metal layer having a halogenated etch product. A carbon-and-nitrogen-containing precursor reacts with the halogenated etch product to form a volatile etch product that can be removed in the gas phase from the etched surface of the metal layer. The surface roughness may be reduced by performing one or more plasma treatments on the etching metal layer after a plurality of etching sequences. Surface roughness is also reduced by controlling the temperature and length of time the metal layer is reacting with the etchant precursors. 1. A method of etching a metal layer on a semiconductor substrate , the method comprising:contacting the semiconductor substrate with a pre-treatment plasma, wherein the pre-treatment plasma is formed from a hydrogen-containing precursor; (i) reducing metal oxide formed on the metal layer to additional metal, and', '(ii) bombarding the metal layer to disorder crystalline regions on the metal layer;, 'treating the metal layer with the pre-treatment plasma to form a pre-treated metal layer, wherein the treating of the metal layer includesreacting the pre-treated metal layer with a halogen-containing precursor, wherein the halogen-containing precursor reacts with the pre-treated metal layer to form a halogenated metal layer comprising a halogenated etch product;removing the halogen-containing precursor from the semiconductor substrate;reacting the halogenated etch product on the halogenated metal layer with a carbon-and-nitrogen-containing precursor to form one or more volatile etch products; andremoving the carbon-and-nitrogen-containing precursor and the ...
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