Substrate processing apparatus and method of machining tubular guard

1. A substrate processing apparatus comprising:

a spin chuck that rotates a substrate around a predetermined rotational axis while holding the substrate;

a liquid supply nozzle that supplies a liquid to the substrate held by the spin chuck; and

a resin-made tubular guard that surrounds the substrate held by the spin chuck,

wherein the tubular guard has an inner peripheral surface and an uneven portion disposed at the inner peripheral surface,

the uneven portion has a plurality of recessed portions and a plurality of protruding portions placed between the recessed portions adjacent to each other,

each of the recessed portions has a width smaller than a diameter of a liquid droplet scattering from the substrate held by the spin chuck and a depth in which the liquid droplet does not come into contact with a bottom portion of each of the recessed portions in a state in which the liquid droplet is in contact with the protruding portions,

each of the protruding portions has a width that is smaller than the diameter of the liquid droplet and that is smaller than the width of the recessed portions, such that

the depth of the recessed portions is 10 μm or more,

the width of the recessed portions is smaller than 1.5 mm, and

the width of the protruding portions is smaller than 1.5 mm.

2. The substrate processing apparatus according to claim 1 , wherein the depth of the recessed portions is 200 μm or less,

the width of the recessed portions is 100 μm or more and is smaller than 1.0 mm, and

the width of the protruding portions is 40 μm or less.

3. The substrate processing apparatus according to claim 1 , wherein average surface roughness of the uneven portion is 3.0 or more and 6.0 or less.

4. The substrate processing apparatus according to claim 1 , wherein the diameter of the liquid droplet is the diameter of the liquid droplet scattering from the substrate that is rotated by the spin chuck at a rotation speed of 600 rpm or more and 1200 rpm or less.

5. The substrate processing apparatus according to claim 1 , wherein the diameter of the liquid droplet is 1.5 mm or less.

6. The substrate processing apparatus according to claim 1 , wherein the recessed portions include a plurality of circular groove portions along a circumferential direction of the inner peripheral surface, and

the circular groove portions are disposed at the inner peripheral surface with intervals between the circular groove portions in an axial direction along a central axis of the inner peripheral surface.

7. The substrate processing apparatus according to claim 6 , wherein the recessed portions include a plurality of intersection groove portions extending in a direction intersecting the circular groove portions, and

a lattice shape is formed by the intersection groove portions and the circular groove portions.

8. The substrate processing apparatus according to claim 1 , wherein the inner peripheral surface of the tubular guard has a tubular surface extending in a vertical direction and an inclined surface that is connected to an upper end of the tubular surface and that extends obliquely with respect to the tubular surface, and

the recessed portions include a plurality of first recessed portions formed at the inclined surface.

9. The substrate processing apparatus according to claim 8 , wherein the recessed portions include a plurality of second recessed portions formed at the tubular surface.

10. The substrate processing apparatus according to claim 9 , wherein the protruding portions include a plurality of first protruding portions placed between the first recessed portions adjacent to each other and a second protruding portion placed between the second recessed portions adjacent to each other, and

a width of the first protruding portions is smaller than a width of the second protruding portion.

11. The substrate processing apparatus according to claim 1 , wherein the tubular guard is made of hydrophobic resin.

12. A substrate processing apparatus comprising:

a spin chuck that holds a substrate so that the substrate rotates around a predetermined rotational axis;

a liquid supply nozzle that supplies a liquid to the substrate held by the spin chuck; and

a resin-made tubular guard surrounding the spin chuck,

wherein the tubular guard has an inner peripheral surface and an uneven portion disposed at the inner peripheral surface,

the uneven portion has a plurality of recessed portions and a plurality of protruding portions placed between the recessed portions adjacent to each other,

each of the recessed portions has a depth of 10 μm or more and a width smaller than 1.5 mm, and

each of the protruding portions has a width that is smaller than the width of the recessed portions and that is smaller than 1.5 mm.

13. The substrate processing apparatus according to claim 12 , wherein the width of the recessed portions is 100 μm or more and is smaller than 1.0 mm,

the depth of the recessed portions is 200 μm or less, and

the width of the protruding portions is 40 μm or less.

14. The substrate processing apparatus according to claim 12 , wherein average surface roughness of the inner peripheral surface is 3.0 or more and 6.0 or less.