Selective silicon oxide etchant formulation including fluoride salt, chelating agent, and glycol solvent
AssigneeAdvanced Technology Materials, Inc.
InventorsWilliam A. Wojtczak, Long Nguyen, Stephen A. Fine
Life of this patent
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Abstract
The formulations of the present invention etch doped silicon oxide compounds, such as BPSG and PSG layers, at rates greater than or equal to the etch rate of undoped silicon oxide such as thermal oxide. The formulations have the general composition of a chelating agent, preferably weakly to moderately acidic (0.1-10%; preferably 0.2-2.8%); a fluoride salt, which may be ammonium fluoride or an organic derivative of either ammonium fluoride or a polyammonium fluoride (1.65-7%; preferably 2.25-7%); a glycol solvent (71-98%; preferably 90-98%); and optionally, an amine.
Claims13
A chemical formulation for etching various types of silicon oxide, consisting essentially of;
- a chelating agent, a fluoride salt, and a glycol solvent, wherein said chelating agent is weakly to moderately acidic, and consists of approximately 0.1-10% by weight of the formulation;
- and wherein said fluoride salt consists of a compound selected from the group consisting of ammonium fluoride, an organic derivative of ammonium fluoride, and a organic derivative of a polyammonium fluoride;
- and wherein said fluoride salt consists of approximately 1.65-7% by weight of the formulation;
- and wherein said glycol solvent consists of approximately 83-98.25% by weight of said formulation;
- and wherein said chelating agent is selected from the group consisting of:
- Iminodiacetic acid
- Malonic acid
- Oxalic acid
- Succinic acid
- Boric acid
- Malic acid
- 2,4-Pentanedione.
A chemical formulation for etching various types of silicon oxide, consisting essentially of:
- a chelating agent, a fluoride salt, and a glycol solvent, wherein said chelating agent is weakly to moderately acidic, and consists of approximately 0.1-10% by weight of the formulation;
- and wherein said fluoride salt consists of a compound selected from the group consisting of ammonium fluoride, an organic derivative of ammonium fluoride, and a organic derivative of a polyammonium fluoride;
- and wherein said fluoride salt consists of approximately 1.65-7% by weight of the formulation;
- and wherein said glycol solvent consists of 73-98.25% by weight of said formulation;
- and further including an amine, wherein said amine consists of approximately 0.1-10% by weight of said formulation;
- and wherein said chelating agent is selected from the group consisting of:
- Iminodiacetic acid
- Malonic acid
- Oxalic acid
- Succinic acid
- Boric acid
- Malic acid
- 2,4-Pentanedione.
Dependencies are inferred from the claim text.