Fairchild Camera and Instrument Corp.

Thomas Keyser

James Montague Cleeves

Michael E Thomas

John M Pierce

A method for impregnating copper into aluminum interconnect lines on a semiconductor device is disclosed. In a first embodiment, an interconnect pattern is formed on an aluminum layer by etching while the aluminum is substantially free from copper, and the copper is thereafter introduced to the formed interconnect lines. In a second embodiment, copper is introduced to the aluminum layer prior to formation of the desired interconnect pattern. The copper-rich layer is removed from the areas to be etched prior to etching. The method facilitates chlorine plasma etching of the aluminum which is inhibited by the presence of copper. The method is also useful with various wet etching processes where the formation of a copper-rich layer is found to stabilize the aluminum layer during subsequent processing .

Impregnation of aluminum interconnects with copper

The disclosure relates to techniques for etching layered materials to produce features with beveled edges, for example, wells in silicon oxide layers employed in integrated circuit fabrication. An anisotropic etch may be employed to form wells with vertical walls in the silicon oxide layer, and an isotropic etch may be employed to bevel peripheral corners of the walls. In preferred embodiments, a double mask of a photoresist layer on an underlying thin film may be used to define the limits of the anisotropic and isotropic etches, respectively.

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Mountain View, CA, United States of America

Thomas Keyser