Patent ID: 8119544
Filing Date: 2012-02-21
Classification: C23C,H01L,Y02E,Y02P

Abstract:
1. A film formation method for a semiconductor process for forming a silicon nitride film as a product film on a plurality of target substrates supported at intervals in a vertical direction on a support member within a process field inside a process container configured to be selectively supplied with a silicon source gas and a nitriding gas and communicating with an exciting mechanism for generating plasma to excite the nitriding gas, the method performing a film formation process on batches of target substrates continuously one batch by one batch and composing the film formation process of a main stage with an auxiliary stage, the main stage performing a plurality of main cycles to laminate thin films respectively formed by the main cycles, each of the main cycles comprising: a first supply step of supplying the silicon source gas to the process field while maintaining a shut-off state of supply of the nitriding gas to the process field; and a second supply step of supplying the nitriding gas to the process field while maintaining a shut-off state of supply of the silicon source gas to the process field, the second supply step of the main stage including an excitation period of supplying the nitriding gas to the process field while exciting the nitriding gas by means of plasma generated by the exciting mechanism, and the auxiliary stage performing a plurality of auxiliary cycles to laminate thin films respectively formed by the auxiliary cycles, each of the auxiliary cycles comprising: a first supply step of supplying the silicon source gas to the process field while maintaining a shut-off state of supply of the nitriding gas to the process field; and a second supply step of supplying the nitriding gas to the process field while maintaining a shut-off state of supply of the silicon source gas to the process field, the second supply step of the auxiliary stage having no excitation period of exciting the nitriding gas by means of plasma generated by the exciting mechanism, wherein a by-product film is deposited on an inner surface of the process container by the film formation process, and the by-product film includes a main stage by-product film deposited by the main stage and having a higher stress due to use of the plasma and an auxiliary stage by-product film deposited by the auxiliary stage and having a lower stress due to the nonuse of plasma, the auxiliary stage is at only the beginning or the ending of the film formation process, or at only both the beginning and the ending of the film formation process, so as to form a by-product film structure on the inner surface of the process container by performing the film formation process on the batches of target substrates continuously one batch by one batch such that first portions corresponding to the main stage by-product film and second portions corresponding to the auxiliary stage by-product film are alternately deposited to suppress generation of particles from the first portions corresponding to the main stage by-product film, and the number of main cycles forming the main stage is larger than the number of auxiliary cycles forming the auxiliary stage such that the auxiliary stage provides part of the silicon nitride film thereby formed with a thickness of 20% or less of a total thickness of the silicon nitride film to prevent the silicon nitride film from being adversely affected in quality by the auxiliary stage.