Method for selective CMP of polysilicon
AssigneesClarkson University, Infotonics Technology Center Inc.
InventorsSuryadevara V. Babu, Anita Natarajan, Sharath Hegde
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Abstract
A method of removing polysilicon in preference to silicon dioxide and/or silicon nitride by chemical mechanical polishing. The method removes polysilicon from a surface at a high removal rate while maintaining a high selectivity of polysilicon to silicon dioxide and/or a polysilicon to silicon nitride. The method is particularly suitable for use in the fabrication of MEMS devices.
Claims16
A method for selectively removing polysilicon from a surface in preference to silicon dioxide and/or silicon nitride, the method comprising:
- a) providing a polishing slurry having a pH of from about 8 to about 11 that comprises colloidal silica abrasive particles dispersed in water and an additive compound selected from the group consisting of lysine, lysine monohydrochloride and arginine;
- b) disposing the polishing slurry between a polishing pad and the surface;
- and
- c) pressing the polishing pad and the surface into contact with each other while the polishing pad and surface are moving relative to each other with the polishing slurry disposed therebetween to remove polysilicon from the surface at a removal rate of 100 nm/min or greater while maintaining a selectivity ratio of polysilicon to silicon dioxide and/or of polysilicon to silicon nitride of 30 or greater.
A method for selectively removing polysilicon from a surface in preference to silicon dioxide and/or silicon nitride, the method comprising:
- a) providing a polishing slurry having a pH of from about 8 to about 11 that comprises
- i) from about 5% to about 15% by weight of colloidal silica abrasive particles having a mean average diameter of from about 25 nm to about 75 nm dispersed in water,
- ii) from about 1% to about 3% by weight of arginine, and
- iii) about 1% by weight of picolinic acid;
- b) disposing the polishing slurry between a polishing pad and the surface;
- and
- c) pressing the polishing pad and the surface into contact with each other while the polishing pad and surface are moving relative to each other with the polishing slurry disposed therebetween to remove polysilicon from the surface at a removal rate of 100 nm/min or greater while maintaining a selectivity ratio of polysilicon to silicon dioxide and/or of polysilicon to silicon nitride of 30 or greater.
A method for selectively removing polysilicon from a surface in preference to silicon dioxide and/or silicon nitride, the method comprising:
- a) providing a polishing slurry having a pH of from about 8 to about 11 that comprises calcined ceria abrasive particles dispersed in water and an additive compound, wherein said additive compound is selected from the group consisting of lysine, lysine monohydrochloride and arginine;
- b) disposing the polishing slurry between a polishing pad and the surface;
- and
- c) pressing the polishing pad and the surface into contact with each other while the polishing pad and surface are moving relative to each other with the polishing slurry disposed therebetween to remove polysilicon from the surface at a removal rate of 100 nm/min or greater while maintaining a selectivity ratio of polysilicon to silicon dioxide and/or of polysilicon to silicon nitride of 30 or greater.
Dependencies are inferred from the claim text.