GCIB smoothing of the contact level to improve PZT films
AssigneeTexas Instruments Incorporated
InventorsLindsey Hall, Sanjeev Aggarwal, Satyavolu Srinivas Papa Rao
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Abstract
A ferroelectric capacitor stack is formed over a metal-dielectric interconnect layer. After forming the interconnect layer, the surface of the interconnect layer is treated with gas cluster ion beam (GCIB) processing. Prior to this processing, the surface typically includes metal recesses. The GCIB processing smoothes these recesses and provides a more level surface on which to form the ferroelectric capacitor stack. When the ferroelectric capacitor stack is formed on this leveled surface, leakage is reduced and yields increased as compared to the case where GCIB processing is not used.
Claims21
A method of forming a FeRAM, comprising:
- forming a transistor on a semiconductor substrate;
- forming an interconnect layer over the transistor, the interconnect layer comprising an upper surface and a contact plug extending down to the underlying transistor;
- treating the upper surface of the interconnect layer and contact plug using a gas cluster ion beam;
- forming a bottom electrode layer, a ferroelectric dielectric layer, and a top electrode layer over the treated upper surface;
- forming a hard mask layer over top electrode layer;
- patterning the hard mask;
- and
- selectively etching the top electrode layer, the ferroelectric dielectric layer, and the bottom electrode layer to define a capacitor stack using the hard mask.
A process of forming a ferroelectric capacitor stack over an interconnect layer comprising a dielectic with conductive plugs extending therethrough, comprising:
- smoothing a surface of the interconnect layer using gas cluster ion beam processing;
- and
- forming the ferroelectric capacitor stack over the smoothed surface.
Dependencies are inferred from the claim text.