Heat treatment method and heat treatment apparatus of thin film
A semiconductor wafer, on the surface of which a silicon dioxide base material and an amorphous silicon thin film are formed in this order, is carried into a chamber. An insulated gate bipolar transistor (IGBT) is connected with a power supply circuit to a flash lamp, and the IGBT makes an energization period to the flash lamp to be 0.01 millisecond or more and 1 millisecond or less, consequently making a flash light irradiation time to be 0.01 millisecond or more and 1 millisecond or less. Since a flash heat treatment is performed with a remarkably short flash light irradiation time, the excessive heating of the thin film of amorphous silicon is suppressed and harmful influence such as the exfoliation of the film is prevented.
1. A heat treatment method for performing a heat treatment of a thin film formed on a base material, the thin film being made of material different from the base material,
the heat treatment method comprising the steps of:
(a) accommodating the base material, on which the thin film is formed, in a chamber and holding the base material; and
(b) heating said thin film by irradiating said thin film with flash light with an irradiation time of 0.01 millisecond or more and of 1 millisecond or less,
further comprising the steps of:
(c) performing exhaust from said chamber; and
(d) supplying a treating gas into said chamber, wherein
a mixed gas in which a reactive gas reacting with said thin film and an inert gas are mixed is supplied into said chamber in said step (d), and wherein
further comprising the steps of:
(e) measuring a concentration of the reactive gas in the mixed gas in said chamber; and
(f) adjusting the concentration of the reactive gas in the mixed gas by adjusting at least either of flows of the reactive gas and the inert gas based on a measured result in said step (e), wherein
a thin film of a high-dielectric-constant film formed on a base material of silicon by an atomic layer deposition method is heated such that crystallinity is given to the thin film in said step (b), wherein
a mixed gas in which helium or argon is mixed with nitrogen is supplied into said chamber when a film thickness of said high-dielectric-constant film is smaller than a predetermined value, and wherein
a mixed gas in which nitrogen is mixed with oxygen is supplied into said chamber when the film thickness of said high-dielectric-constant film is larger than the predetermined value.