Method of manufacturing semiconductor device
A technique capable of controlling in-plane uniformity of a film formed on a substrate includes a step of forming a film on a substrate by performing a predetermined number of cycles in which a step of supplying a metal-containing gas to the substrate and a step of supplying a reducing gas containing an element that becomes a solid by itself to the substrate are performed in a time-division manner. The reducing gas has a property of changing a deposition rate of the film from an increasing rate to a decreasing rate in accordance with the exposure amount of the reducing gas with respect to the substrate. In the step of supplying the reducing gas, the exposure amount of the reducing gas with respect to the substrate is adjusted in accordance with the property of the reducing gas.
1. A method of manufacturing a semiconductor device, the method comprising:
forming a film on a substrate by performing a cycle a predetermined number of times, wherein the cycle includes:
supplying a metal-containing gas to the substrate,
supplying a reducing gas containing an element that becomes a solid by itself to the substrate, wherein the reducing gas has a property of changing a deposition rate of the film from an increasing rate to a decreasing rate in accordance with an increasing of an exposure amount of the reducing gas with respect to the substrate, and
adjusting, the exposure amount of the reducing gas with respect to the substrate for a subsequent cycle in accordance with the property of the reducing gas
wherein the supplying the metal-containing gas and supplying the reducing gas in the cycle are performed non-simultaneously.
2. The method according to claim 1 , wherein
the property of the reducing gas is that
in a case where an exposure amount d of the reducing gas with respect to the substrate is less than a first exposure amount d 1 (d<d 1 ), as the exposure amount of the reducing gas with respect to the substrate increases, the deposition rate of the film increases,
in a case where the exposure amount d of the reducing gas with respect to the substrate is the first exposure amount d 1 or more and less than a second exposure amount d 2 (d 1 ≤d<d 2 ), the deposition rate of the film is maintained almost constant regardless of the exposure amount of the reducing gas with respect to the substrate,
in a case where the exposure amount d of the reducing gas with respect to the substrate is the second exposure amount d 2 or more and less than a third exposure amount d 3 (d 2 ≤d<d 3 ), as the exposure amount of the reducing gas with respect to the substrate increases, the deposition rate of the film decreases, and
in a case where the exposure amount d of the reducing gas with respect to the substrate is the third exposure amount d 3 or more (d 3 ≤d), the film is hardly formed regardless of the exposure amount of the reducing gas with respect to the substrate.
3. The method according to claim 2 , wherein the first exposure amount d 1 is the exposure amount of the reducing gas with respect to the substrate when molecules of the reducing gas are adsorbed on the entire surface of the substrate,
the second exposure amount d 2 is the exposure amount of the reducing gas with respect to the substrate when molecules of the reducing gas are adsorbed in multiple layers at least on a partial region on the substrate, and
the third exposure amount d 3 is the exposure amount of the reducing gas with respect to the substrate when molecules of the reducing gas are adsorbed in multiple layers on the entire surface of the substrate.
4. The method according to claim 2 , wherein
by supplying the reducing gas to a central portion of the substrate so as to satisfy a relationship of dy≥d 1 provided that dy represents the exposure amount of the reducing gas with respect to the central portion of the substrate, and by supplying the reducing gas to an outer peripheral portion of the substrate so as to satisfy a relationship of d 1 >dx provided that dx represents the exposure amount of the reducing gas with respect to the outer peripheral portion of the substrate, the film having a protrusion shape is formed on the substrate.
5. The method according to claim 4 , wherein the reducing gas is supplied vertically with respect to a surface of the substrate from above.
6. The method according to claim 2 , wherein
by supplying the reducing gas to a central portion of the substrate so as to satisfy a relationship of d 2 >dy provided that dy represents the exposure amount of the reducing gas with respect to the central portion of the substrate, and by supplying the reducing gas to an outer peripheral portion of the substrate so as to satisfy a relationship of d 2 ≤dx provided that dx represents the exposure amount of the reducing gas with respect to the outer peripheral portion of the substrate, the film having a protrusion shape is formed on the substrate.
7. The method according to claim 6 , wherein the reducing gas is supplied horizontally with respect to a surface of the substrate.
8. The method according to claim 2 , wherein
by supplying the reducing gas to a central portion of the substrate so as to satisfy a relationship of dy≥d 2 provided that dy represents the exposure amount of the reducing gas with respect to the central portion of the substrate, and by supplying the reducing gas to an outer peripheral portion of the substrate so as to satisfy a relationship of d 2 >dx provided that dx represents the exposure amount of the reducing gas with respect to the outer peripheral portion of the substrate, the film having a recess shape is formed on the substrate.
9. The method according to claim 8 , wherein the reducing gas is supplied vertically with respect to a surface of the substrate from above.
10. The method according to claim 2 , wherein by supplying the reducing gas to a central portion of the substrate so as to satisfy a relationship of dy<d 1 provided that dy represents the exposure amount of the reducing gas with respect to the central portion of the substrate, and by supplying the reducing gas to an outer peripheral portion of the substrate so as to satisfy a relationship of d 1 ≤dx provided that dx represents the exposure amount of the reducing gas with respect to the outer peripheral portion of the substrate, the film having a recess shape is formed on the substrate.
11. The method according to claim 10 , wherein the reducing gas is supplied horizontally with respect to a surface of the substrate.
12. The method according to claim 2 , wherein
by supplying the reducing gas to the entire surface of the substrate in the exposure amount of the first exposure amount d 1 or more and less than the second exposure amount d 2 , the film having an almost flat shape is formed on the substrate.
13. The method according to claim 1 , wherein the exposure amount is adjusted by controlling at least one of supply amount, supply time, and pressure of the reducing gas.
14. The method according to claim 1 , wherein the film is formed while a temperature of the substrate is maintained at 60° C. or higher and 230° C. or lower.
15. The method according to claim 1 , wherein the reducing gas is a boron containing gas.
16. The method according to claim 1 , wherein the reducing gas is diborane (B 2 H 6 ).
17. The method according to claim 1 , wherein the element that becomes the solid by itself is boron (B) or silicon (Si).
18. The method according to claim 1 , wherein the reducing gas is silane (SiH 4 ) gas.
19. The method according to claim 1 , wherein the reducing gas is a disilane (Si 2 H 6 ).