Film formation method and apparatus for semiconductor process

A method for using a film formation apparatus to form a silicon nitride film by CVD on a plurality of target substrates while suppressing particle generation,

• the apparatus comprising
• a process container having a vertically elongated process field configured to accommodate the target substrates,
• a support member configured to support the target substrates at intervals in a vertical direction inside the process field,
• an exciting mechanism attached on a sidewall of the process container and including a plasma generation area communicating with the process field and an electrode extending along the plasma generation area and configured to be supplied with a radio frequency power, the plasma generation area being present in a recess formed on the process container and extending over a vertical length corresponding to the process field,
• a process gas supply system configured to selectively supply a silicon source gas and nitriding gas into the process field, such that the silicon source gas is supplied into the process field not through the plasma generation area and the nitriding gas is supplied into the process field through the plasma generation area, and the silicon source gas and the nitriding gas are supplied to form essentially horizontal gas flows in the process field over a length corresponding to the process field in a vertical direction, and
• an exhaust system configured to exhaust gas from inside the process container through an exhaust passage connected to the process container,
• the method comprising:
• conducting a pre-coating process by performing a plurality of pre-cycles in the process container, with the support member placed in the process field and set in an empty state or with dummy substrates supported thereon in place of the target substrates, to form a pre-coating film on an inner surface of the process container and on a surface of the support member, each of the pre-cycles including
• a first pre-supply step of supplying the silicon source gas into the process container without supplying the nitriding gas into the process container,
• then a first pre-purge step of exhausting gas from inside the process container without supplying the silicon source gas and the nitriding gas into the process container,
• then a second pre-supply step of supplying the nitriding gas into the process container without supplying the silicon source gas into the process container, and
• then a second pre-purge step of exhausting gas from inside the process container without supplying the silicon source gas and the nitriding gas into the process container,
• wherein the second pre-supply step comprises no period of exciting the nitriding gas by the exciting mechanism;
• and
• after the pre-coating process is finished, conducting a film formation process by performing a plurality of main cycles in the process container, with the support member placed in the process field and set with the target substrates supported thereon, to laminate thin films respectively formed by the main cycles on the target substrates, thereby forming a silicon nitride film with a determined thickness, each of the main cycles including
• a first supply step of supplying the silicon source gas into the process container without supplying the nitriding gas into the process container,
• then a first purge step of exhausting gas from inside the process container without supplying the silicon source gas and the nitriding gas into the process container,
• then a second supply step of supplying the nitriding gas into process container without supplying the silicon source gas into the process container, and
• then a second purge step of exhausting gas from inside the process container without supplying the silicon source gas and the nitriding gas into the process container,
• wherein the film formation process repeats a first cycle set and a second cycle set mixedly a plurality of times without an essential change in a heating temperature set to the process field,
• the first cycle set being composed of a main cycle or main cycles in which the second supply step includes an excitation period of supplying the nitriding gas while exciting the nitriding gas by the exciting mechanism, and
• the second cycle set being composed of a main cycle or main cycles in which the second supply step includes no period of exciting the nitriding gas by the exciting mechanism,
• wherein the pre-coating process and the film formation process are combined to suppress particle generation due to by-product films deposited inside the process container, by use of collaboration of film stress reduction provided by the second cycle set of the film formation process with the pre-coating film on the inner surface of the process container and on the surface of the support member.