Clean for high density capacitors
AssigneeTexas Instruments Incorporated
InventorLindsey H. Hall
Life of this patent
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Abstract
One aspect of the invention relates to a method of cleaning high density capacitors. According to the method, the capacitors are cleaned with a plasma that includes fluorine-containing radicals. The plasma removes a small layer from the capacitors, including their sidewalls, and thereby removes surface contaminants. The method is effective even when the capacitors include hard-to-etch dielectric materials, such as tantalum and hafnium oxides. In a preferred embodiment, the plasma clean is combined with a solvent clean.
Claims20
A method of forming and post ash cleaning a high density capacitor, comprising:
- providing a capacitor stack on a substrate, the capacitor stack comprising a dielectric selected from the group consisting of hafnium and tantalum compounds;
- forming a resist over the capacitor stack;
- patterning the resist to form a mask;
- etching the capacitor stack to form the high density capacitor using the mask;
- ashing the resist to leave an ash residue;
- and
- then, cleaning the high density capacitor with a plasma comprising fluorine-containing radicals.
A method of cleaning sidewalls of a capacitor comprising a dielectric core comprising a dielectric selected from the group consisting of ferroelectric materials, hafnium compounds, and tantalum compounds, comprising:
- etching the sidewalls with a plasma comprising fluoride radicals.
A method of cleaning a high density capacitor having sidewalls, comprising:
- providing a capacitor stack on a substrate, the capacitor stack comprising a dielectric selected from the group consisting of hafnium and tantalum compounds, a top electrode layer, and a bottom electrode layer;
- etching the top electrode layer, dielectric, and bottom electrode layer of the capacitor stack to form the high density capacitor having sidewalls;
- cleaning the sidewalls with a solvent;
- and
- after said etching step, plasma etching the sidewalls in an atmosphere comprising at least about 0.1 mole % of a fluorine compound.
Dependencies are inferred from the claim text.