Gate electrode forming methods using conductive hard mask
AssigneeInternational Business Machines Corporation
InventorsOleg Gluschenkov, Dae-Gyu Park
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Abstract
Methods related to formation of a gate electrode are disclosed that employ a conductive hard mask as a protective layer during a photoresist removal process. In preferred embodiments, the conductive hard mask includes a metal containing conductor or a metal silicide. The invention prevents process damage on the gate dielectric during wet and/or dry resist strip, and since the conductive hard mask cannot be etched in typical resist strip chemistries, the invention also protects a metal electrode under the hard mask. The steps disclosed allow creation of a multiple work function metal gate electrode, or a mixed metal and polysilicon gate electrode, which do not suffer from the problems of the related art.
Claims20
A method for preparing an area for fabrication of a metal gate electrode with multiple work functions, the method comprising the steps of:
- depositing a material having a first work function;
- forming a conductive hard mask including at least one of a metal containing conductor and a metal silicide over the material;
- using a photoresist mask to remove the conductive hard mask from an area for a device having a second, different work function selective to the material;
- and
- removing the photoresist mask, leaving the conductive hard mask for use in removing the material from the area and inclusion in the metal gate electrode.
A method of forming a gate electrode, the method comprising the steps of:
- forming a gate dielectric;
- depositing a first metallic conductor having a first work function;
- depositing a conductive hard mask on the first metallic conductor including at least one of a metal containing conductor and a metal silicide;
- removing the conductive hard mask from an area for a particular device type using a photoresist mask selective to the first metallic conductor;
- removing the photoresist mask;
- removing the first metallic conductor in the area with a remaining portion of the conductive hard mask protecting the first metallic conductor;
- depositing a conductor;
- and
- forming the gate electrode including the remaining portion of the conductive hard mask.
A method of forming a metal gate electrode with multiple work function, the method comprising the steps of:
- depositing a dielectric on a substrate;
- depositing a first metallic conductor having a first work function over the dielectric;
- depositing a conductive hard mask on the first metallic conductor including at least one of a metal containing conductor and a metal silicide;
- removing the conductive hard mask from an area for a particular device type using a photoresist mask;
- removing the photoresist mask to a remaining portion of the conductive hard mask;
- removing the first metallic conductor in the area using the remaining portion of the conductive hard mask to protect the first metallic conductor;
- depositing a second metal having a second, different work function in the area;
- depositing a silicon-containing conductor over the first and second metals;
- and
- forming the metal gate electrode including the remaining portion of the conductive hard mask.
Dependencies are inferred from the claim text.