Electrostatic chuck including upper plate and substrate processing apparatus including the same
An electrostatic chuck according to the disclosure includes a chuck base, and an upper plate. The upper plate includes a base portion, and a first contact pattern, a second contact pattern and an outer dam protruding from the base portion. The outer dam surrounds the first contact pattern structure and the second contact pattern structure. A distance of the second contact pattern structure to the outer dam is less than a distance from the first contact pattern structure to the outer dam. A surface roughness of a top surface of the second contact pattern structure is greater than a surface roughness of a top surface of the first contact pattern structure.
1 . An electrostatic chuck comprising:
a chuck base; and
an upper plate,
wherein the upper plate comprises a base portion, a first contact pattern structure, a second contact pattern structure, and an outer dam, wherein each of the first contact pattern structure, the second contact pattern structure, and the outer dam protrudes from the base portion,
wherein the outer dam surrounds the first contact pattern structure and the second contact pattern structure,
wherein a distance from the second contact pattern structure to the outer dam is less than a distance from the first contact pattern structure to the outer dam, and
wherein a surface roughness of a surface of each protrusion of the second contact pattern structure is greater than a surface roughness of a surface of each protrusion of the first contact pattern structure.
2 . The electrostatic chuck according to claim 1 , wherein a diameter of the surface of the second contact pattern structure is smaller than a diameter of the surface of the first contact pattern structure.
3 . The electrostatic chuck according to claim 2 , wherein the diameter of the surface of the second contact pattern structure is 0.4 to 0.6 mm; and
the diameter of the surface of the first contact pattern structure is 0.9 to 1.1 mm.
4 . The electrostatic chuck according to claim 1 , wherein the surface roughness of the surface of the second contact pattern structure is 0.7 to 0.9 μm; and
the surface roughness of the surface of the first contact pattern structure is 0.08 to 0.12 μm.
5 . The electrostatic chuck according to claim 1 , wherein the upper plate further comprises a third contact pattern structure protruding from the base portion;
a distance from the third contact pattern structure to the outer dam is less than the distance from the second contact pattern structure to the outer dam; and
a surface roughness of a surface of the third contact pattern structure is smaller than the surface roughness of the surface of the second contact pattern structure.
6 . The electrostatic chuck according to claim 1 , wherein the upper plate comprises an inner gas hole extending through the base portion and an outer gas hole extending through the base portion;
a distance from the outer gas hole to the outer dam is less than the distance from the second contact pattern structure to the outer; and
a distance from the inner gas hole to the outer dam is greater than the distance from the second contact pattern structure to the outer dam.
7 . The electrostatic chuck according to claim 6 , wherein the distance from the inner gas hole the outer dam is less than the distance from the first contact pattern structure to the outer dam.
8 . The electrostatic chuck according to claim 1 , wherein the second contact pattern structure comprises (i) a first set of protrusions forming a first concentric circle having a first diameter and (ii) a second set of protrusions forming a second concentric circle having a second diameter less than the first diameter, and
wherein a plurality of gas holes are located between the first set of protrusions and the second set of protrusions.
9 . A substrate processing apparatus comprising:
a chamber; and
an electrostatic chuck provided in the chamber,
wherein the electrostatic chuck comprises an upper plate and a chuck base supporting the upper plate,
wherein the upper plate comprises a base portion, a first contact pattern structure, a second contact pattern structure, and an outer dam, wherein each of the first contact pattern structure, the second contact pattern structure, and the outer dam protrudes from a top surface of the base portion,
wherein a distance from the second contact pattern structure to the outer dam is less than a distance from the first contact pattern structure to the outer dam,
wherein a diameter of a surface of the second contact pattern structure is smaller than a diameter of a surface of the first contact pattern structure,
wherein the diameter of the surface of the second contact pattern structure is 0.4 to 0.6 mm, and the diameter of the surface of the first contact pattern structure is 0.9 to 1.1 mm,
wherein the first contact pattern structure comprises a plurality of first contact pattern structures,
wherein the second contact pattern structure comprises a plurality of second contact pattern structures,
wherein a number of the plurality of first contact pattern structures is between 714 to 734 and a number of the plurality of second contact pattern structures is between 47 to 67, and
wherein a contact ratio of the outer dam with a substrate is greater than a contact ratio of the plurality of first contact pattern structures and the plurality of second contact pattern structures with the substrate.
10 . The substrate processing apparatus according to claim 9 , wherein the second contact pattern structure comprises two second contact pattern structures adjacent to each other;
the first contact pattern structure comprises two first contact pattern structures adjacent to each other; and
a distance between the two second contact pattern structures is greater than a distance between the two first contact pattern structures.
11 . The substrate processing apparatus according to claim 9 , wherein the upper plate comprises an inner gas hole and an outer gas hole extending through the base portion; and
a distance from each of the inner gas hole and the outer gas hole to the outer dam is less than the distance from the first contact pattern structure to the outer dam.
12 . The substrate processing apparatus according to claim 11 , wherein the second contact pattern structure is located between the inner gas hole and the outer gas hole.
13 . The substrate processing apparatus according to claim 11 , wherein a distance from at least one second contact pattern structure from among the plurality of second contact pattern structures to the outer dam is less than the distance from the outer gas hole to the outer dam; and
wherein a distance from at least one other second contact pattern structure from among the plurality of second contact pattern structures to the outer dam is greater than the distance from the outer gas hole to the outer dam.
14 . An electrostatic chuck comprising:
an upper plate configured to chuck a substrate thereon; and
a chuck base supporting the upper plate,
wherein the upper plate comprises:
a base portion comprising an inner region and an outer region surrounding the inner region,
first contact pattern structures protruding from the inner region,
second contact pattern structures protruding from the outer region,
third contact pattern structures,
an outer dam surrounding the first contact pattern structures and the second contact pattern structures,
a plurality of inner gas holes, and
a plurality of outer gas holes,
wherein each of the first contact pattern structures and each of the second contact pattern structures has a form of a circular pillar,
wherein a first distance between two adjacent ones of the first contact pattern structures is smaller than a second distance between two adjacent ones of the second contact pattern structures,
wherein each second contact pattern structure is spaced apart from an adjacent second contact pattern structure by the second distance,
wherein at least a portion of the first contact pattern structures is at a central area of the upper plate,
wherein the central area of the upper plate includes a center of the upper plate,
wherein each inner gas hole from the plurality of inner gas holes is between the first contact pattern structures and the second contact pattern structures, and
wherein each outer gas hole from the plurality of outer gas holes is between the second contact pattern structures and the third contact pattern structures.
15 . The electrostatic chuck according to claim 14 , wherein the outer region comprises a first portion connected to the inner region, and a second portion surrounding the first portion; and
the second contact pattern structures protrude from the first portion.
16 . The electrostatic chuck according to claim 15 , wherein the third contact pattern structures protrude from the second portion; and
a distance between two adjacent ones of the third contact pattern structures is smaller than the distance between the two adjacent ones of the second contact pattern structures.
17 . The electrostatic chuck according to claim 14 , wherein a ratio of a surface area of the outer dam to a surface area of the base portion is greater than a ratio of a surface area of the first contact pattern structures and the second contact pattern structures to the surface area of the base portion.
18 . The electrostatic chuck according to claim 17 , wherein the ratio of the surface area of the outer dam to the surface area of the base portion is 1.28 to 1.48%; and
the ratio of the surface area of the first contact pattern structures and the second contact pattern structures to the surface area of the base portion is 0.77 to 0.97%.