Etching method for forming micro silicon pattern in semiconductor manufacturing process
A process of realizing a silicon micropattern having a large aspect ratio in a semiconductor-manufacturing process, and a novel wet etching method that includes treating an organic carbon film layer so that a hydrofluoric-acid-resistant material is selectively attached to the organic carbon film layer and then wet etching the same using an aqueous solution containing hydrofluoric acid, thus forming a pattern, are proposed. In the method of forming the pattern by wet etching, etching is performed so that an active region having a depth of several μm in an object to be etched is not damaged when a pattern having a small CD is formed, thereby exhibiting an effect of providing a method of forming a micropattern.
1. A method of forming a silicon pattern in an etching process of a silicon layer in a semiconductor-manufacturing process, the method comprising:
i) sequentially layering an organic film and an inorganic film on an object to be etched, applying a photoresist for pattern formation thereon, and performing exposure and developing, thus forming a photoresist pattern;
ii) performing dry etching with a gas that is capable of being used for etching using the formed photoresist pattern so that a portion of an organic carbon film remains directly on the object to be etched;
iii) applying a hydrofluoric-acid-resistant material on a remaining portion of the organic carbon film;
iv) performing a bake process at a temperature of 50° C. to 400° C. for 1 to 5 minutes; and
v) performing wet etching using an aqueous solution containing hydrofluoric acid,
wherein a coating thickness of the hydrofluoric-acid-resistant material is 10 to 1,000 Å.
2. The method of claim 1 , wherein the layering the organic film and the inorganic film on the object to be etched includes a coating method or a chemical or physical deposition method.
3. The method of claim 1 , wherein a carbon content of the organic carbon film layered on the object to be etched is 30 to 100%.
4. The method of claim 1 , wherein a light source for forming the silicon pattern has a wavelength of 13.5 nm, 198 nm, 248 nm, or 365 nm and includes an E-beam.
5. The method of claim 1 , wherein as the gas that is capable of being used for the dry etching after the pattern is formed, an inert gas including argon and nitrogen, a gas including molecules containing one or more fluorine elements, and an oxygen gas are used alone or in combination.
6. The method of claim 1 , wherein the hydrofluoric-acid-resistant material is a material that is capable of being selectively applied on the organic carbon film, and polyimide, polyethylene, polypropylene, polyvinylidene, polyvinyl chloride, polyimidazole, polycarbonate, polystyrene, polyethylene terephthalate, polybutylene terephthalate, polyphenylene ether, and polyvinylidene fluoride are used alone or in combination.
7. The method of claim 1 , wherein the hydrofluoric-acid-resistant material is applied to a thickness of 10 to 500 Å.