Method for forming an ultrafine metal pattern using an electron beam

Claim 1

A method for forming an ultrafine metal pattern, comprising the steps of: providing a substrate on which a metal film is formed, said substrate and metal film being provided in a vacuum specimen chamber; introducing a gaseous negative type resist for an electron beam into the specimen chamber, a vapor pressure of the negative type resist being in a range from 10 -7 to 10 -5 Torr; providing a vacuum in said specimen chamber, and forming a negative type resist molecular layer comprising negative type resist molecules absorbed on a surface of the metal film; irradiation an electron beam whose beam diameter is finely converged to approximately 100 Å or less onto the metal film in the gaseous negative type resist atmosphere while scanning a desired pattern, an accelerating voltage of the electron beam being in a range from 0.5 to approximately 6 kV, and having a beam current in a range from 10 -13 to 10 -7 A; molecules in said negative type resist molecular layer where said electron beam is irradiated causing a cross linking reaction; repetitively executing scanning of the electron beam for said desired pattern until a thickness of the desired pattern which was initially irradiated and comprising the negative type resist molecules which caused the cross linking reaction reaches a desired thickness; selectively removing portions of the negative type resist molecular layer to which the electron beam was not irradiated by a wet process using a solvent for the negative type resist, a resist pattern remaining which comprises the negative type resist molecules which caused the cross linking reaction, and a width of said resist pattern being substantially equal to said beam diameter of the electron beam; aniostropically etching the metal film while suing the resist pattern as a mask so as to form a metal ultrafine line of 100 Å or less; and removing the resist pattern by a wet process using a solvent.

Claim 2

A method for forming an ultrafine metal pattern, comprising the steps of: providing a substrate on which a metal film is formed, said substrate and metal film being provided in a vacuum specimen chamber; introducing a gaseous negative type resist for an electron beam into the specimen chamber, a vapor pressure of the negative type resist being in a range from 10 -7 to 10 -5 Torr; providing a vacuum in said specimen chamber, and forming a negative type resist molecular layer comprising negative type resist molecules absorbed on a surface of the metal film; irradiation an electron beam whose beam diameter is finely converged to approximately 100 Å or less onto the metal film in the gaseous negative type resist atmosphere while scanning a desired pattern, an accelerating voltage of the electron beam being in a range from 0.5 to approximately 6 kV, and having a beam current in a range from 10 -13 to 10 -7 A; molecules in said negative type resist molecular layer where said electron beam is irradiated causing a cross linking reaction; repetitively executing scanning of the electron beam for said desired pattern until a thickness of the desired pattern which was initially irradiated and comprising the negative type resist molecules which caused the cross linking reaction reaches a desired thickness; selectively removing portions of the negative type resist molecular layer to which the electron beam was not irradiated by a wet process using a solvent for the negative type resist, a resist pattern remaining which comprises the negative type resist molecules which caused the cross linking reaction, and a width of said resist pattern being substantially equal to said beam diameter of the electron beam; aniostropically etching the metal film while suing the resist pattern as a mask so as to form a metal ultrafine line of 100 Å or less; and removing the resist pattern by a wet process using a solvent.