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US 6,669,857 B2Granted
Process for etching bismuth-containing oxide films
AssigneeInfineon Technologies AG
InventorFrank Hintermaier
Life of this patent
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Abstract
A process is described for etching oxide films containing at least one bismuth-containing oxide, in particular a ferroelectric bismuth-containing mixed oxide. A substrate onto which at least one oxide film containing at least one bismuth-containing oxide has been applied is provided. An etching solution containing from 2 to 20% by weight of a fluoride ion donor, from 15 to 60% by weight of nitric acid and from 20 to 83% by weight of water is brought into contact with the substrate so that the etching solution can react with the oxide film. The etching solution is removed from the substrate. The etching solution is also used in a process for structuring bismuth-containing oxide films.
Claims30
An etching process, which comprises the steps of:
- providing a substrate onto which at least one oxide film containing at least one bismuth-containing oxide has been applied;
- bringing an etching solution containing from 2 to 20% by weight of a fluoride ion donor, from 15 to 60% by weight of nitric acid and from 20 to 83% by weight of water, into contact with the substrate for reacting the etching solution with the oxide film;
- selecting the fluoride ion donor from the group consisting of ammonium fluoride NH4F and ammonium hydrogen fluoride NH4HF2;
- and
- removing the etching solution from the substrate.
2 more elements
A structuring process, which comprises the steps of:
- providing a substrate with an oxide film containing at least one bismuth-containing oxide disposed on a surface of the substrate;
- applying a mask to the oxide film;
- bringing an etching solution containing from 2 to 20% by weight of a fluoride ion donor, from 15 to 60% by weight of nitric acid and from 20 to 80% by weight of water into contact with the substrate for reacting the etching solution with regions of the oxide film not covered by the mask;
- selecting the fluoride ion donor from the group consisting of ammonium fluoride NH4F and ammonium hydrogen fluoride NH4HF2;
- removing the etching solution from the substrate;
- and
- removing the mask.
4 more elements
An etching process, which comprises the steps of:
- providing a substrate onto which at least one oxide film containing at least one bismuth-containing oxide has been applied;
- bringing an etching solution containing from 2 to 20% by weight of a fluoride ion donor, from 15 to 60% by weight of nitric acid and from 20 to 83% by weight of water, into contact with the substrate for reacting the etching solution with the oxide film;
- adding at least one substance selected from the group consisting of mineral acids, hydrochloric acid HCl, sulfuric acid H2SO4, inorganic salts of mineral acids, ammonium chloride NH4Cl, and ammonium bromide NH4Br, to the etching solution to regulate the pH;
- and
- removing the etching solution from the substrate.
2 more elements
An etching process, which comprises the steps of:
- providing a substrate onto which at least one oxide film containing at least one bismuth-containing oxide has been applied;
- bringing an etching solution containing from 2 to 20% by weight of a fluoride ion donor, from 15 to 60% by weight of nitric acid and from 20 to 83% by weight of water, into contact with the substrate for reacting the etching solution with the oxide film;
- adding at least one substance selected from the group consisting of organic surface-active substances, alcohols, ethanol, isopropanol, acids, acetic acid, and propionic acid, to the etching solution;
- and
- removing the etching solution from the substrate.
2 more elements
An etching process, which comprises the steps of:
- providing a substrate onto which at least one oxide film containing at least one bismuth-containing oxide has been applied;
- forming the oxide film to contain at least one niobium-doped oxide having a composition of SrBi2Ta2−xNbxO9 where 0≦x≦2;
- bringing an etching solution containing from 2 to 20% by weight of a fluoride ion donor, from 15 to 60% by weight of nitric acid and from 20 to 83% by weight of water, into contact with the substrate for reacting the etching solution with the oxide film;
- and
- removing the etching solution from the substrate.
2 more elements
An etching process, which comprises the steps of:
- providing a substrate onto which at least one oxide film containing at least one bismuth-containing oxide has been applied;
- bringing an etching solution containing from 2 to 20% by weight of a fluoride ion donor, from 15 to 60% by weight of nitric acid and from 20 to 83% by weight of water, into contact with the substrate for reacting the etching solution with the oxide film;
- removing the etching solution from the substrate;
- and
- treating the substrate with an aqueous hydrochloric acid solution after removal of the etching solution.
2 more elements
An etching process, which comprises the steps of:
- providing a substrate onto which at least one oxide film containing a ferroelectric bismuth-containing mixed oxide;
- bringing an etching solution containing from 2 to 20% by weight of a fluoride ion donor, from 15 to 60% by weight of nitric acid and from 20 to 83% by weight of water, into contact with the substrate for reacting the etching solution with the oxide film;
- aiding an action of the etching solution on the bismuth-containing mixed oxide by mechanical rubbing;
- and
- removing the etching solution from the substrate.
2 more elements
A structuring process, which comprises the steps of:
- providing a substrate with an oxide film containing at least one bismuth-containing oxide disposed on a surface of the substrate;
- applying a mask to the oxide film;
- bringing an etching solution containing from 2 to 20% by weight of a fluoride ion donor, from 15 to 60% by weight of nitric acid and from 20 to 80% by weight of water into contact with the substrate for reacting the etching solution with regions of the oxide film not covered by the mask;
- adding at least one substance selected from the group consisting of mineral acids, hydrochloric acid HCl, sulfuric acid H2SO4, inorganic salts of mineral acids, ammonium chloride NH4Cl, and ammonium bromide NH4Br, to the etching solution to regulate the pH;
- removing the etching solution from the substrate;
- and
- removing the mask.
4 more elements
A structuring process, which comprises the steps of:
- providing a substrate with an oxide film containing at least one bismuth-containing oxide disposed on a surface of the substrate;
- applying a mask to the oxide film;
- bringing an etching solution containing from 2 to 20% by weight of a fluoride ion donor, from 15 to 60% by weight of nitric acid and from 20 to 80% by weight of water into contact with the substrate for reacting the etching solution with regions of the oxide film not covered by the mask;
- adding at least one substance selected from the group consisting of organic surface-active substances, alcohols, ethanol, isopropanol, acids, acetic acid, and propionic acid, to the etching solution;
- removing the etching solution from the substrate;
- and
- removing the mask.
4 more elements
A structuring process, which comprises the steps of:
- providing a substrate with an oxide film containing at least one bismuth-containing oxide disposed on a surface of the substrate;
- applying a mask to the oxide film;
- bringing an etching solution containing from 2 to 20% by weight of a fluoride ion donor, from 15 to 60% by weight of nitric acid and from 20 to 80% by weight of water into contact with the substrate for reacting the etching solution with regions of the oxide film not covered by the mask;
- forming the oxide film to contain at least one niobium-doped oxide of a composition SrBi2Ta2−xNbxO9 where 0≦x≦2;
- removing the etching solution from the substrate;
- and
- removing the mask.
4 more elements
A structuring process, which comprises the steps of:
- providing a substrate with an oxide film containing at least one bismuth-containing oxide disposed on a surface of the substrate;
- applying a mask to the oxide film;
- bringing an etching solution containing from 2 to 20% by weight of a fluoride ion donor, from 15 to 60% by weight of nitric acid and from 20 to 80% by weight of water into contact with the substrate for reacting the etching solution with regions of the oxide film not covered by the mask;
- removing the etching solution from the substrate;
- removing the mask;
- and
- treating the substrate with an aqueous hydrochloric acid solution after removal of the etching solution.
4 more elements
A structuring process, which comprises the steps of:
- providing a substrate with an oxide film containing a ferroelectric bismuth-containing mixed oxide disposed on a surface of the substrate;
- applying a mask to the oxide film;
- bringing an etching solution containing from 2 to 20% by weight of a fluoride ion donor, from 15 to 60% by weight of nitric acid and from 20 to 80% by weight of water into contact with the substrate for reacting the etching solution with regions of the oxide film not covered by the mask;
- aiding an action of the etching solution on the bismuth-containing mixed oxide by mechanical rubbing;
- removing the etching solution from the substrate;
- and
- removing the mask.
4 more elements
Dependencies are inferred from the claim text.