Process for etching
Patent 5110408 Issued on May 5, 1992. Estimated Expiration Date: 
February 20, 2011. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.
February 20, 2011. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.Patent ReferencesPlasma etchant mixture Anisotropic plasma etching of tungsten Anisotropic silicon etching in fluorinated plasma Patent #: 4741799 InventorsAssigneeApplicationNo. 658254 filed on 02/20/1991US Classes:216/75, Substrate contains elemental metal, alloy thereof, or metal compound204/192.37, Silicon containing216/79, Etching silicon containing substrate252/79.1, ETCHING OR BRIGHTENING COMPOSITIONS257/E21.218, Plasma etching; reactive-ion etching (EPO)257/E21.234, Characterized by their behavior during process, e.g., soluble mask, redeposited mask (EPO)257/E21.311, Using plasma (EPO)257/E21.312, Of silicon-containing layer (EPO)257/E21.314, Using mask (EPO)438/695, Simultaneous etching and coating438/720Electrically conductive material (e.g., metal, conductive oxide, etc.)ExaminersPrimary: Powell, William A.Attorney, Agent or FirmInternational ClassesH01L 021/306B44C 001/22 C23F 001/02 C03C 015/00 AbstractThe present invention relates to the etching of a gate film, a tungsten film, a silicon film, etc. In the present invention, use is made of an etching gas comprising a mixture composed of a reductive fluoride gas, a hydrocarbon gas and a halogen gas having a larger atomic diameter than a material to be etched, or a mixture composed of a reductive fluoride gas and a Cl-containing hydrocarbon gas, and the process comprises the step of conducting anisotropic etching of a material to be etched with an etching gas (a reductive fluoride gas), the step of forming a protective film by a depositing gas (a hydrocarbon gas), and the step of removing excess deposits formed as the protective film by means of a gas reactive with the protective film (a halogen gas or a Cl-containing hydrogen gas), wherein anisotropic etching is conducted by forming a protective film on a side wall while removing excess deposits formed as the protective film, thus enabling the anisotropic etching to be conducted with good accuracy. |
| ||||||||||||||
