Methods of forming hemispherical grained silicon on a template on a semiconductor work object
AssigneeMicron Technology, Inc.
InventorsGuoqing Chen, James Pan
Life of this patent
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Abstract
The present invention provides a method of preparing a surface of a silicon wafer for formation of HSG structures. The method contemplates providing a wafer having at least one HSG template comprising polysilicon formed in BPSG, the HSG template being covered by silicon dioxide. The wafer is treated with a cleaning agent to clean the surface of the wafer. Next, the wafer is treated with a conditioning agent. The conditioning agent removes native oxide from the HSG template without excessively etching structural BPSG. Preferably, the conditioning agent also removes a thin layer of polysilicon on the HSG template. The wafer is then transferred to a process chamber for HSG formation.
Claims42
A method of forming a semiconductor wafer with the formation of HSG structures, comprising:
- providing a work object with a surface having a polysilicon feature;
- treating the surface with a cleaning agent to clean the surface;
- treating the surface, before HSG formation, with a conditioning agent to condition the surface for HSG formation by removing a thin layer of polysilicon from the polysilicon feature;
- transferring the work object to HSG seeding and annealing process steps;
- and
- forming HSG on the work object.
A method of forming a semiconductor wafer with the formation of HSG structures, comprising;
- providing a work object having a surface with plural polysilicon features, the polysilicon feature being covered by silicon oxide;
- treating the surface with a cleaning agent to clean the surface;
- treating the surface, before HSG formation, with a conditioning agent to condition the surface for HSG formation by removing a thin layer of polysilicon from the polysilicon feature until the silicon oxide layer and at least about 5 Å of the polysilicon features on the work object has been removed;
- the conditioning agent being an aqueous solution containing about 40 wt. % NH4F, about 1.0–1.3 wt. % phosphoric acid (H3PO4), and deionized water as a remainder, and transferring the conditioned work object to HSG annealing and seeding process steps.
A method of forming HSG structures on a semiconductor wafer, comprising:
- providing a clean wafer having a surface with a polysilicon feature;
- treating the surface, before HSG formation, with a conditioning agent to condition the surface for HSG formation by removing a thin layer of polysilicon from the polysilicon feature, and
- transferring the conditioned wafer to HSG seeding and annealing process steps in which HSG is formed on the polysilicon feature.
A method of forming a semiconductor wafer having HSG structures, comprising:
- providing a work object having a surface with a polysilicon feature;
- treating the surface, before HSG formation, with a conditioning agent to condition the surface for HSG formation by removing a thin layer of polysilicon from the polysilicon feature, the conditioning agent having a pH of about 4.0–7.5 and an etch selectivity ratio for BPSG to silicon dioxide of about 1 to about 2, the conditioning agent removing at least 5 Å of polysilicon from the work object;
- and
- transferring the conditioned work object to HSG seeding an annealing process steps.
A method of forming a semiconductor work object with HSG structures, comprising:
- providing a work object having a surface with a polysilicon feature;
- treating the surface with a cleaning agent to clean the surface;
- treating the surface, before HSG formation, with a conditioning agent by removing a thin layer of polysilicon from the polysilicon feature, the conditioning agent comprising an aqueous solution having a pH of between about 4.0 to about 7.5 to condition the surface for HSG formation;
- and
- transferring the conditioned work object to HSG seeding and annealing process steps.
Dependencies are inferred from the claim text.