JP7307582B2 - Substrate holding member - Google Patents

Description

The present invention relates to a substrate holding member used to hold a substrate such as a semiconductor wafer by vacuum suction.

In a semiconductor manufacturing process, etc., there is a substrate holding member that has a large number of protrusions (pins) on the surface of a substrate to hold the substrate, and holds the substrate by evacuating the space between the back surface of the substrate and the surface of the substrate. Are known.
The projections formed on the surface of the substrate are the portions that come into direct contact with the substrate, and if particles are interposed between the projections and the substrate, the substrate locally swells, degrading the surface accuracy of the substrate. This leads to deterioration and occurrence of defocus errors. 2. Description of the Related Art In recent years, miniaturization and high density of semiconductors have progressed, and the deterioration of surface accuracy of substrates directly affects the decrease in yield.
Therefore, as a measure to minimize the generation of particles caused by the contact between the base and the substrate, the contact area between the protrusions and the substrate is reduced by reducing the number of protrusions or designing the protrusions in a tapered shape. is known (see, for example, Patent Document 1).

JP-A-10-242255

However, excessive reduction in the diameter of the protrusions reduces the strength of the protrusions, and may induce particle generation due to damage to the tips of the protrusions. Furthermore, the volume of the space defined by the substrate holding member and the substrate placed thereon increases by the amount corresponding to the reduction in the number of projections and the reduction in the diameter of the projections. Therefore, the development of the negative pressure state in the space may be delayed, and it may be determined that an abnormality has occurred in the vacuum development state of the space, and the operation of the vacuum suction device may be stopped.

Accordingly, the present invention provides a substrate holding member capable of avoiding erroneous recognition of the state of vacuum development during vacuum suction of the substrate while reducing the contact area between the plurality of projections and the substrate and suppressing the generation of particles. intended to provide

The substrate holding member of the first aspect of the present invention comprises
a substrate;
a plurality of protrusions protruding from the main surface of the base;
at least one ventilation path passing through the base and having an opening on a main surface of the base; and an annular protrusion projecting from the main surface of the base and surrounding the plurality of protrusions and the opening of the ventilation path. A substrate holding member comprising
Each of the plurality of convex portions has a first convex element protruding from the main surface of the base, and an end face protruding from an end face of the first convex element and having a smaller area than the end face of the first convex element. a cylindrical second convex element;
Some of the plurality of convex portions are formed as enlarged convex portions having a larger volume of the first convex element than other convex portions .

According to the substrate holding member having this configuration, the substrate is placed on the main surface side of the substrate holding member, and the space defined by the main surface of the substrate and the back surface of the substrate is vacuum-sucked through the ventilation path to form a negative pressure region. As a result, the substrate is held by the substrate holding member while the rear surface of the substrate is in contact with the end surfaces of the plurality of protrusions. A first convex element in which each convex portion protrudes from the main surface of the base, and a second convex element which protrudes from an end face of the first convex element and has an end face having a smaller area than the end face of the first convex element. , is composed of Therefore, the strength of each projection is improved while reducing the contact area between the substrate and each projection.

Some of the plurality of convex portions are selectively formed as enlarged convex portions, that is, convex portions having a larger volume of the first convex element than other convex portions. Therefore, while reducing the number of the plurality of protrusions in order to further reduce the contact area between the protrusions and the substrate, an increase in the volume of the space defined by the main surface of the base and the back surface of the substrate is suppressed. Alternatively, it is avoided, and a situation in which it is erroneously recognized that an abnormality has occurred in the vacuum development state of the space is avoided.

The substrate holding member according to the second aspect of the present invention includes
a substrate;
a plurality of protrusions protruding from the main surface of the base;
at least one ventilation path passing through the base and having an opening on a main surface of the base; and an annular protrusion projecting from the main surface of the base and surrounding the plurality of protrusions and the opening of the ventilation path. A substrate holding member comprising
Each of the plurality of convex portions has a first convex element protruding from the main surface of the base, and an end face protruding from an end face of the first convex element and having a smaller area than the end face of the first convex element. a cylindrical second convex element;
Some of the plurality of convex portions are formed as enlarged convex portions having a larger volume of the first convex element than the other convex portions,
one or more of the enlarged protrusions are formed around the opening of the ventilation path on the main surface of the base,
The plurality of enlarged projections are formed on the main surface of the base so as to surround the opening of the ventilation path . Here, the periphery of the opening of the ventilation path means, for example, a region within 4 mm from the edge of the opening.

According to the substrate holding member having this configuration, the main surface of the base and the rear surface of the substrate are separated by the plurality of enlarged convex portions arranged around the opening of the ventilation path, particularly the first convex elements constituting the enlarged convex portions. Increased fluid resistance is achieved in at least one azimuthal range around the opening of the ventilation path in the space defined by. Therefore, at the time of vacuum suction of the space, especially in the initial stage, it is possible to avoid a situation in which it is erroneously recognized that an abnormality has occurred in the vacuum development state due to excessively low fluid resistance in the space.

According to the substrate holding member having this configuration, the main surface of the base and the back surface of the substrate are separated from each other by the plurality of enlarged projections arranged so as to surround the opening of the ventilation path, particularly the first projection elements constituting the enlarged projections. The fluid resistance is increased in a plurality of azimuth ranges around the opening of the ventilation path in the space defined by and. Therefore, at the time of vacuum suction of the space, especially in the initial stage, it is possible to more reliably avoid a situation in which it is erroneously recognized that an abnormality has occurred in the vacuum development state due to excessively low fluid resistance in the space.

A substrate holding member according to a third aspect of the present invention comprises:
a substrate;
a plurality of protrusions protruding from the main surface of the base;
at least one ventilation path passing through the interior of the base body and having an opening on the main surface of the base body; A substrate holding member comprising: a projecting outer annular projection;
Each of the plurality of convex portions has a first convex element protruding from the main surface of the base, and an end face protruding from an end face of the first convex element and having a smaller area than the end face of the first convex element. a second convex element;
Some of the plurality of convex portions are formed as enlarged convex portions having a larger volume of the first convex element than the other convex portions,
In the main surface of the base, the enlarged convex portion protrudes from the main surface of the base and surrounds the opening of the ventilation path inside the outer annular convex portion. and a plurality of cylindrical second convex elements protruding from the end faces of the first convex elements .

According to the substrate holding member having this configuration, the plurality of enlarged projections arranged around the opening of the ventilation path, particularly the inner annular projection serving as the first projection element shared by the plurality of enlarged projections, allows the substrate to be held. In the space defined by the main surface and the back surface of the substrate, the fluid resistance is increased in all directions around the opening of the ventilation path. Therefore, when vacuuming the space, especially in the initial stage, it is possible to more reliably avoid a situation in which it is erroneously recognized that an abnormality has occurred in the vacuum development state due to excessively low fluid resistance in the space.

1 is a top view of a substrate holding member as one embodiment of the present invention; FIG. FIG. 2 is a longitudinal sectional view of the substrate holding member taken along line II-II in FIG. 1; Explanatory drawing about the structure of an expansion convex part and another convex part. FIG. 11 is an explanatory diagram regarding an arrangement mode of an enlarged projection with respect to an opening of a ventilation path; Explanatory drawing about the modification of an expansion convex part.

(First embodiment)

(composition)
The substrate holding member as one embodiment of the present invention shown in FIGS. , a ventilation path 2 having an opening 20 in the first main surface of the base 1, a plurality of protrusions 10 protruding from the first main surface 101 of the base 1, and an outer annular protrusion surrounding the opening 20 of the ventilation path 2. 14 and.

The substrate 1 is made of a ceramic sintered body such as SiC, AlN, Al ₂ O ₃ or the like in a substantially disk shape. Each of the plurality of protrusions 10, the outer annular protrusion 14, and the ventilation path 2 is formed by grinding, blasting, milling, laser processing, or a combination thereof. Each of the first principal surface 101 and the second principal surface 102 of the substrate 1 is formed substantially planar.

Each of the plurality of projections 10 has a shape in which a small-diameter cylinder concentrically overlaps a large-diameter cylinder. The plurality of protrusions 10 are arranged to form lattice points of a lattice such as a triangular lattice or a square lattice on the first main surface 101 of the base 1, or arranged along each of a plurality of concentric circles, or They may be regularly arranged, such as regularly arranged along each of a plurality of rays extending from the center, or they may be irregularly arranged. Among the plurality of protrusions 10, the arrangement mode or regularity of the protrusions 10 constituting one protrusion group (for example, the plurality of protrusions 10 arranged close to the opening 20 of the ventilation path 2) and arrangement mode or rule of the protrusions 10 constituting another group of protrusions different from the one group (for example, a plurality of protrusions 10 arranged apart from the periphery of the opening 20 of the ventilation path 2) may be different from each other.

Each of the plurality of projecting portions 10 is divided into a first projecting portion 11 and a second projecting portion 12 (see FIG. 3). The first projecting portion 11 includes a substantially cylindrical first projecting element 111 projecting from the first main surface 101 of the base 1 and an end surface 1110 of the first projecting element 111 projecting from the end surface 1110 of the first projecting element 111 . and a generally cylindrical second convex element 112 having a smaller area end face 1120 . The second convex portion 12 includes a substantially cylindrical first convex element 121 protruding from the first main surface 101 of the base body 1 and an end surface 1210 of the first convex element 121 . and a generally cylindrical second convex element 122 having a smaller area end face 1220 .

The height H111 of the first convex element 111 of the first convex portion 11 and the height H112 of the second convex element 112, respectively, and the height H121 of the first convex element 121 and the second convex element 122 of the second convex portion 12 are equal to each of the heights H122 of . That is, the height H11 of the first convex portion 11 (the amount of protrusion from the first main surface 101) and the height H12 of the second convex portion 12 are equal.

The diameter W112 of the second convex element 112 of the first convex portion 11 and the diameter W122 of the second convex element 122 of the second convex portion 12 are equal. On the other hand, the diameter W111 of the first convex element 111 of the first convex portion 11 is smaller than the diameter W121 of the first convex element 121 of the second convex portion 12 . As a result, the volume (=π(W121) ² ×(H121)) of the first convex element 121 of the second convex portion 12 as the enlarged convex portion is equal to the volume of the first convex element 121 of the first convex portion 11 as the other convex portion. It is larger than the volume of the element 111 (=π(W111) ² ×(H111)).

In addition to the relationship "W111<W121 and H111=H121", "W111=W121 and H111<H121", "W111<W121 and H111<H121", "W111<W121 and H111>H121", or "W111>W121 and H111 <H121”, the volume of the first convex element 121 of the second convex portion 12 may be larger than the volume of the first convex element 111 of the first convex portion 11 .

Each of the first convex portion 11 and the second convex portion 12 is formed by concentrically overlapping a small diameter cylinder (second convex elements 112, 122) on a large diameter cylinder (first convex elements 111, 121). Other shapes such as cylinders, prisms, truncated cones, and other shapes in which truncated pyramids are arbitrarily combined and stacked may be used. The upper end surface of the first convex element 111 of the first convex portion 11 and the lower end surface of the substantially frustum-shaped second convex element 112 are the same, and the first convex element 111 and the second convex element 112 are continuous. , the first convex portion 11 does not have to have a step. The upper end surface of the first convex element 121 of the second convex portion 12 and the lower end surface of the substantially frustum-shaped second convex element 122 are the same, and the first convex element 121 and the second convex element 122 are continuous. , the second convex portion 12 does not have to have a step.

As shown in FIG. 4, on the first principal surface 101 of the base 1, a plurality (for example, six) of a plurality of (for example, six) contained in a substantially circular first region S1 that spreads with the opening 20 of the ventilation path 2 as a reference. At least one of the protrusions 10 is formed as a second protrusion 12 . A plurality of (18) protrusions included in a substantially circular second region S2 having a diameter larger than that of the first region S1 and extending from the opening 20 of the ventilation path 2 on the first main surface 101 of the base body 1. At least one of 10 may be formed as the second protrusion 12 .

In the vertical cross-sectional view of the substrate holding member, the shape of the outer annular projection 14 is substantially rectangular, substantially trapezoidal, semi-elliptical, semi-circular, or rectangular and semi-circular with a diameter equal to one side of the rectangle. Various shapes, such as combined shapes, are also possible. Note that the outer annular projection 14 may be omitted. The height position (projection amount from the first main surface 101) of the upper end surface 140 of the outer annular protrusion 14 with respect to the first main surface 101 of the base body 1 is the upper end surface 1120 of the first protrusion 11 and the second It is designed to be lower than or equal to the height position of the upper end surface 1220 of the projection 12 .

In the base body 1, one opening 20 of the ventilation path 2 arranged in the center and six openings 20 of the ventilation path 2 arranged so as to have six-fold symmetry with respect to the center on the outside thereof. and are formed. The ventilation path 20 is formed by a substantially cylindrical hole penetrating through the base 1 from the first main surface 101 to the second main surface 102 of the base 1 . The number, layout, and extension of the ventilation paths 2 may be arbitrarily changed. For example, the ventilation path 2 may be arranged to have mirror symmetry with respect to a plane perpendicular to the first main surface 101 of the base 1, and asymmetrically so as not to have rotational symmetry or mirror symmetry. may be placed in

Note that the substrate holding member is schematically shown in the drawings, and the aspect ratio, spacing, number, etc. of the constituent elements of the substrate holding member are basically different from the actual design values. This is the same for all embodiments.

(function)
According to the substrate holding member as one embodiment of the present invention, the substrate W is placed on the side of the first main surface 101 of the substrate holding member, and is defined by the first main surface 101 of the substrate 1 and the back surface of the substrate W. The space is vacuum-sucked through the ventilation path 2 to form a negative pressure area, so that the substrate W is held by the substrate holding member while the rear surface of the substrate W is in contact with the respective end surfaces of the plurality of projections 10 . (See Figures 1 and 2). The first convex portion 11 has a first convex element 111 protruding from the first main surface 101 of the base 1 and an end surface 1110 of the first convex element 111, and has a smaller area than the end surface 1110 of the first convex element 111. and a second convex element 112 having an end surface 1120 (see FIG. 3). The second convex portion 12 has a first convex element 121 protruding from the first main surface 101 of the base 1 and an end surface 1210 of the first convex element 121, and has a smaller area than the end surface 1210 of the first convex element 121. and a second convex element 122 having an end surface 1220 (see FIG. 3). Therefore, while reducing the contact area between the substrate W and each of the projections 11 and 12, the strength of each of the projections 11 and 12 is improved. The substrate W can be uniformly brought into contact with the upper end surface of the convex portion 10, and the flatness of the substrate W can be improved when it is held by suction on the substrate holding member. Then, on the front surface (upper surface) of the substrate W, predetermined processing such as exposure processing for forming a circuit of a desired pattern can be performed.

The volume of the first convex element 121 of the second convex portion 12 (enlarged convex portion), which is a partial convex portion among the plurality of convex portions 10, is equal to the volume of the first convex element 121 of the first convex portion 11, which is the other convex portion. larger than the volume of 111. Therefore, while attempting to reduce the number of the plurality of protrusions 10 in order to further reduce the contact area between the protrusions 10 and the substrate W, the area defined by the first main surface 101 of the base 1 and the back surface of the substrate W is reduced. This suppresses or avoids an increase in the volume of the space, thereby avoiding a situation in which it is erroneously recognized that an abnormality has occurred in the vacuum development state of the space. In particular, the plurality of second projections 12 (see FIG. 4) arranged around the opening 20 of the ventilation path 2, particularly the first projection elements 121 constituting the second projections 12, make the first projections of the base 1 In the space defined by the main surface 101 and the back surface of the substrate W, fluid resistance is increased in one or more azimuth ranges around the opening 20 of the ventilation path 2 . Therefore, at the time of vacuum suction of the space, especially in the initial stage, it is possible to avoid a situation in which it is erroneously recognized that an abnormality has occurred in the vacuum development state due to excessively low fluid resistance in the space.

(Example)

(Example 1)
As the base 1, a base made of a substantially disk-shaped silicon carbide sintered body having a diameter of 300 mm and a thickness of 5 mm was prepared. On the first main surface 101 of the substrate 1, 19,900 convex portions 10 were arranged in a triangular lattice with an interval of 2.0 mm so that the density was uniform over the entire first main surface 101 of the substrate 1. FIG. The first convex portion 11 has a substantially cylindrical second convex element with a diameter of φ0.2 mm and a height of 0.05 mm on a substantially cylindrical first convex element 111 with a diameter of φ0.5 mm and a height of 0.25 mm. 112 were formed in a stepped columnar shape as if 112 were concentrically stacked. The second convex portion 12 has a substantially cylindrical second convex element with a diameter of φ0.2 mm and a height of 0.05 mm on a substantially cylindrical first convex element 121 with a diameter of φ1.0 mm and a height of 0.25 mm. 122 were formed in a stepped columnar shape as if 122 were concentrically stacked.

On the first main surface 101 of the substrate 1, an outer annular projection 14 having an inner diameter of φ299 mm, a width of 0.5 mm, and a height of 0.3 mm was formed to surround the plurality of projections 10. As shown in FIG. On the first main surface 101 of the base body 1, 18 ventilation paths with a diameter of φ1.0 mm are arranged along each of three annular rings with different distances from the center so as to have 6-fold symmetry with respect to the center. Two openings 20 were formed. Here, the six (6) are included in a substantially circular first region S1 (see FIG. 4) with the opening 20 of each ventilation path 2 as a reference, and are arranged on concentric circles so as to surround the opening 20. A total of 108 protrusions 10 were formed as the second protrusions 12 .
Thus, the substrate holding device of Example 1 was produced. In this case, the contact area ratio, which is the ratio of the area of the upper end surfaces of the plurality of protrusions 10 to the area of the back surface of the disk-shaped substrate W having a diameter of φ300 mm, was 0.90%. By operating the vacuum pump and vacuum-sucking the space between the first main surface 101 of the substrate holding member and the substrate W, the substrate W becomes a high plane without damaging the tips of the plurality of protrusions 10 . It was adsorbed and held by the substrate holding member. An abnormality in the state of vacuum development is detected when the pressure is greater than -50 kPa even after 0.3 seconds have passed since the start of operation of the vacuum pump. In Example 1, an abnormality is detected during vacuum suction. did not

(Example 2)
6 on three concentric circles with different distances from the center so as to be included in a substantially circular second region S2 (see FIG. 4) based on the opening 20 of each ventilation path 2 (see FIG. 4) and surround the opening 20. Only 18 projections 10 arranged one by one (324 in total) were formed as the second projections 12 . Of the 18 second protrusions 12 arranged to surround the opening 20 of each suction path 2, 6 arranged on a circle (included in the first region S1) closest to the opening 20 Each of the second projections 12 has a diameter of φ0.2 mm and a height of 0.05 mm on a substantially cylindrical first projection element 121 having a diameter of φ1.0 mm and a height of 0.25 mm. The convex elements 122 were formed in a stepped cylindrical shape in which the convex elements 122 were concentrically stacked. The six second protrusions 12 arranged on a circle that is the second closest to the opening 20 are arranged on a substantially cylindrical first protrusion element 121 having a diameter of 0.9 mm and a height of 0.25 mm. The substantially cylindrical second projecting elements 122 having a diameter of 0.2 mm and a height of 0.05 mm were concentrically stacked to form a stepped cylindrical shape. The six second projections 12 arranged on the circle farthest from the opening 20 are formed on the substantially cylindrical first projection elements 121 having a diameter of 0.8 mm and a height of 0.25 mm, and a diameter of 0.0 mm. Approximately cylindrical second convex elements 122 of 2 mm in height and 0.05 mm in height were formed in a stepped cylindrical shape in which the second convex elements 122 were concentrically stacked.

A substrate holding member 2 of Example 2 was produced under the same conditions as those of Example 1 except for the above. As in the first embodiment, the vacuum pump is operated to vacuum-suck the space between the first main surface 101 of the substrate holding member and the substrate W, thereby damaging the tips of the plurality of protrusions 10 . The substrate W was sucked and held by the substrate holding member with high flatness. In Example 2, no abnormality was detected during vacuum suction.

(Comparative example)
Regardless of whether the first convex portion 11 or the second convex portion 12, all the convex portions 10 are placed on the substantially cylindrical first convex element 111 having a diameter of φ0.5 mm and a height of 0.25 mm and a diameter of φ0.2 mm. , substantially cylindrical second convex elements 112 having a height of 0.05 mm are concentrically stacked to form a stepped cylindrical shape. A substrate holding member 2 of Comparative Example 1 was produced under the same conditions as in Example 1 except for the above. When the vacuum pump is operated and the space between the first main surface 101 of the substrate holding member and the substrate W is vacuum-sucked, an abnormality presumed to be caused by the delay in negative pressure formation is detected, and the vacuum pump is operated. was stopped.

(Another embodiment of the present invention)
As shown in FIG. 5, it protrudes from the first main surface 101 of the base 1 and surrounds the opening 20 of the ventilation path 2 inside the outer annular protrusion 14 on the first main surface 101 of the base 1 . An extending inner annular convex portion 120 is formed, and an enlarged convex portion includes a first convex element that is the inner annular convex portion 120 and a plurality of convex portions that protrude from the end surface of the inner annular convex portion 120 (first convex element). and the second convex element 122 of .

According to the substrate holding member having this configuration, the space defined by the first main surface 101 of the substrate 1 and the rear surface of the substrate W is divided by the inner annular protrusion 120 arranged around the opening 20 of the ventilation path 2 . In particular, the fluid resistance in the omnidirectional range around the opening 20 of the ventilation path 2 is increased. Therefore, when vacuuming the space, especially in the initial stage, it is possible to more reliably avoid a situation in which it is erroneously recognized that an abnormality has occurred in the vacuum development state due to excessively low fluid resistance in the space.

Reference Signs List 1 Base 2 Ventilation path 10 Protrusion 11 First protrusion 12 Second protrusion (enlarged protrusion) 14 Outer annular protrusion 20 Ventilation path opening 101 First main surface (upper surface) 102 Second main surface (lower surface) 111 First convex element of first convex portion 112 Second convex element of first convex portion 120 Inner annular convex portion 121 122 .. the second convex element of the second convex portion 1200 .. the end surface of the inner annular convex portion 1110 .. the end surface of the first convex element of the first convex portion 1120 . 1210 end face of the first convex element of the second convex portion 1220 end face of the second convex element of the second convex portion W substrate (wafer).

Claims (3)

a substrate;
a plurality of protrusions protruding from the main surface of the base;
at least one ventilation path passing through the base and having an opening on a main surface of the base; and an annular protrusion projecting from the main surface of the base and surrounding the plurality of protrusions and the opening of the ventilation path. A substrate holding member comprising
Each of the plurality of convex portions has a first convex element protruding from the main surface of the base, and an end face protruding from an end face of the first convex element and having a smaller area than the end face of the first convex element. a cylindrical second convex element;
A substrate holding member, wherein some of the plurality of protrusions are formed as enlarged protrusions in which the volume of the first protrusion element is larger than that of other protrusions. a substrate;
a plurality of protrusions protruding from the main surface of the base;
at least one ventilation path passing through the base and having an opening on a main surface of the base; and an annular protrusion projecting from the main surface of the base and surrounding the plurality of protrusions and the opening of the ventilation path. A substrate holding member comprising
Each of the plurality of convex portions has a first convex element protruding from the main surface of the base, and an end face protruding from an end face of the first convex element and having a smaller area than the end face of the first convex element. a cylindrical second convex element;
Some of the plurality of convex portions are formed as enlarged convex portions having a larger volume of the first convex element than the other convex portions,
one or more of the enlarged protrusions are formed around the opening of the ventilation path on the main surface of the base,
The substrate holding member, wherein the plurality of enlarged projections are formed on the main surface of the base so as to surround the opening of the ventilation path . a substrate;
a plurality of protrusions protruding from the main surface of the base;
at least one ventilation path passing through the interior of the base body and having an opening on the main surface of the base body; A substrate holding member comprising: a projecting outer annular projection;
Each of the plurality of convex portions has a first convex element protruding from the main surface of the base, and an end face protruding from an end face of the first convex element and having a smaller area than the end face of the first convex element. a second convex element;
Some of the plurality of convex portions are formed as enlarged convex portions having a larger volume of the first convex element than the other convex portions,
In the main surface of the base, the enlarged convex portion protrudes from the main surface of the base and surrounds the opening of the ventilation path inside the outer annular convex portion. A substrate holding member comprising a plurality of cylindrical second convex elements protruding from an end surface of the first convex element .

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