Substrate processing method
A substrate processing method capable of forming a film with an improved step coverage on a surface of a gap structure having a high aspect ratio includes: providing a gap structure having a first step and a second step portion; supplying gas including a source gas onto the gap structure; generating active species from the source gas; generating neutral molecules by neutralizing the active species, and moving the neutral molecules in a direction toward a lower surface of a recess extending between the first stepped portion and the second stepped portion; and exciting the neutral molecules moving in the direction toward the lower surface.
1 . A substrate processing method comprising:
providing a gap structure having a first step and a second step;
supplying gas including a source gas onto the gap structure;
generating active species from the source gas;
generating neutral molecules by neutralizing the active species, and moving the neutral molecules in a direction toward a lower surface of a recess extending between the first step and the second step;
exciting the neutral molecules that moved in the direction toward the lower surface; and
performing post-treatment of a layer, wherein, during the post-treatment, an overhang portion of the layer is removed.
2 . The substrate processing method of claim 1 , wherein, during the exciting of the neutral molecules, layer formation in a first area adjacent to the lower surface of the recess between the first step and the second step is promoted.
3 . The substrate processing method of claim 2 , wherein, during the generating of active species from the source gas, layer formation in the second area adjacent to an edge of the first step and the second step is promoted.
4 . The substrate processing method of claim 3 , wherein, a step coverage of the layer formed over the first area and the second area improves by the exciting of the neutral molecules and the generating of active species from the source gas.
5 . The substrate processing method of claim 1 , wherein, during the neutralizing of the active species, an edge potential formed at the edge of the first step and the second step is reduced.
6 . The substrate processing method of claim 5 , wherein, while the neutral molecules move in the direction toward the lower surface, remaining active species move in the direction toward the lower surface without being affected by the edge potential.
7 . The substrate processing method of claim 1 , further comprising:
applying plasma in a pulsed manner.
8 . The substrate processing method of claim 7 , wherein, during the applying of plasma, at least one of first frequency RF power of 13 MHz or more and second frequency RF power of 1 MHz or less is applied.
9 . The substrate processing method of claim 7 , wherein
the applying of plasma in a pulsed manner comprises an ON period and an OFF period,
during the ON period, the generating of active species from the source gas is performed, and
during the OFF period, the neutralizing of the active species is performed.
10 . The substrate processing method of claim 9 , wherein the exciting of the neutral molecules that moved in the direction toward the lower surface is performed during the ON period.
11 . The substrate processing method of claim 1 , wherein, during the supplying of gas including a source gas, a reactant gas or a reactive purge gas is supplied together with the source gas.
12 . The substrate processing method of claim 1 , wherein a reactant gas is continuously supplied during the supplying gas including the source gas and the performing post-treatment of the layer.
13 . The substrate processing method of claim 1 , wherein, during the post-treatment, the supplying of the source gas is interrupted.
14 . The substrate processing method of claim 1 , wherein-during the post-treatment, the layer is densified.
15 . The substrate processing method of claim 1 , wherein, a reactant gas is supplied subsequent to the supplying gas including the source gas.
16 . The substrate processing method of claim 1 , wherein RF power supplied during the post-treatment is greater than RF power supplied during the generating of active species from the source gas.
17 . The substrate processing method of claim 1 , wherein a RF frequency during the post-treatment is less than a RF frequency during the generating of active species from the source gas.
18 . The substrate processing method of claim 17 , wherein a RF frequency during the post-treatment further comprises a RF frequency during the generating of active species from the source gas.