JP6212412B2 - Vacuum suction member - Google Patents

Description

  The present invention relates to a vacuum suction member used for sucking and holding a semiconductor wafer or the like.

  In the adsorption member in which a plurality of support protrusions are formed on the surface of the base, the support protrusion is formed of a base made of a silicon carbide sintered body having a truncated cone shape in which a truncated cone-shaped protrusion is formed at the center of the upper surface; It has been proposed to form a protective layer made of a silicon carbide film formed along the surfaces of the base portion and the protruding portion (see Patent Document 1). With this configuration, the generation amount of particles in the protrusion is suppressed.

Japanese Patent No. 50639797

  However, if the space formed between the adsorbing member and an object to be adsorbed such as a semiconductor wafer supported by the adsorbing member so as to come into contact with the plurality of protrusions is too narrow, the gas present in the space When the vacuum is sucked, the rate of increase in the degree of vacuum may be reduced (vacuum responsiveness may deteriorate). On the other hand, if the protruding amount of the protruding portion is increased in order to ensure the space, the protrusion may be bent and the flatness of the object to be adsorbed may be reduced. Moreover, if the space | interval of protrusions is extended too much in order to ensure the width of the said space, the flatness of a to-be-adsorbed object may fall.

  Then, an object of this invention is to provide the vacuum suction member which can aim at the further improvement of vacuum responsiveness and the flatness of a to-be-adsorbed object.

The present invention provides the following vacuum suction members [1] to [2].
[1] A base comprising a base and a plurality of protrusions formed on the surface of the base, wherein the protrusion is formed of a base made of a silicon carbide sintered body, and silicon carbide formed along the surface of the base In a vacuum suction member constituted by a protective layer made of a film, the base portion has a lower prismatic base or a truncated pyramid base, and a columnar or truncated cone projecting upward from the upper end of the lower base The ratio (R1 / R2) of the diameter R1 of the circle forming the lower end contour of the upper base to the diameter R2 of the circle circumscribed by the regular polygon forming the upper end contour of the lower base is 0 .Vacuum included in the range of 30 to 0.60, and the ratio of the height H1 of the upper base to the height H2 of the lower base (H1 / H2) is included in the range of 0.30 to 0.60. Adsorption member.
[2] The vacuum suction member according to [1], wherein central axes of the lower base and the upper base are common.

  According to the vacuum suction member of the present invention, the volume of the lower base can be reduced as compared with a case where a circle circumscribing a regular n-gon that forms the upper end contour of the lower base forms the upper end contour. In other words, the shape is such that a cylinder or a truncated cone having the upper end contour as the circle is partially shaved. Accordingly, the space between the protrusions is narrowed while appropriately securing the volume of the space surrounded by the vacuum suction member and the object to be adsorbed so as to be in contact with the plurality of protrusions from the viewpoint of vacuum response. And the suppression of the height of the upper base is achieved.

  In addition to narrowing the spacing between the protrusions and suppressing the height of the upper base, the shape of the lower base has rotational symmetry with respect to the central axis for improving the rigidity of each protrusion. As a result, even if the weight of the object to be adsorbed is applied to the top surface of the protrusion, the bending of the protrusion is more reliably prevented, and the flatness of the object to be adsorbed is improved.

BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing of the vacuum suction member as one Embodiment of this invention. Sectional drawing of the processus | protrusion which comprises the vacuum suction member as one Embodiment of this invention. The (a) top view and (b) side view of the base which comprise the protrusion of FIG.

(Constitution)
A vacuum suction member 1 as an embodiment of the present invention shown in FIG. 1 includes a base 10 made of a substantially disk-shaped silicon carbide ceramic sintered body and a plurality of bases 10 formed on the upper surface of the base 10. The projection 2 is provided. A vacuum suction path communicating with the upper surface of the base 10 is formed. The plurality of protrusions 2 are arranged to form lattice points of a triangular lattice, and the interval is designed to be 1.00 to 2.50 [mm].

  As shown in FIG. 2, the protrusion 2 is formed integrally with the base 10, and is formed along the upper surface of the base 10 including the base 20 made of a silicon carbide ceramic sintered body and the surface of the base 20. And a protective layer 24 made of a silicon carbide film. The thickness of the protective layer 24 is designed to be in the range of 20 to 100 [μm].

  The base 20 includes a lower base 22 having a regular hexagonal column shape and a substantially cylindrical or disk-shaped upper base 21 protruding upward from an upper end of the lower base 22. The lower base portion 22 may be a regular n-gonal prism shape other than a hexagonal prism, such as a regular pentagonal prism or a regular octagonal prism, or may be a regular prism base shape. The upper base 21 may have a truncated cone shape. The central axis of the lower base 22 and the central axis of the upper base 21 may coincide with each other or may be shifted.

  The ratio (R1 / R2) of the diameter R1 of the circle forming the lower end contour of the upper base 21 to the diameter R2 of the regular hexagon circumscribed circle (see broken line) forming the upper end contour of the lower base 22 shown in FIG. Is included in the range of 0.30 to 0.60. For example, R1 is designed to be within a range of 0.15 to 0.30 [mm], and R2 is designed to be within a range of 0.25 to 0.60 [mm].

  When R1 is less than 0.15 [mm], the rigidity of the protrusion 2 becomes insufficient, and good flatness of an object to be adsorbed such as a semiconductor wafer cannot be secured. When R1 exceeds 0.30 [mm], the contact area between the protrusion 2 and the object to be adsorbed becomes large, and particles increase when adsorbing the object to be adsorbed, which is not preferable.

  When R2 is less than 0.25 [mm] or R1 / R2 is greater than 0.60, the rigidity of the lower base portion 22 is insufficient, and good flatness of the object to be adsorbed cannot be ensured. When R2 exceeds 0.60 [mm], the diameter of the lower base portion 22 is increased, and the vacuum response is lowered, which is not preferable. When R1 / R2 is less than 0.30, the area of the upper surface of the lower base 22 becomes large, and this is not preferable because particles increase when the object to be adsorbed is adsorbed.

  The ratio (H1 / H2) of the height H1 of the upper base 21 to the height H2 of the lower base 22 shown in FIG. 3B is included in the range of 0.30 to 0.60. For example, H1 is designed to be within a range of 0.06 to 0.12 [mm], and H2 is designed to be within a range of 0.15 to 0.40 [mm].

  When H1 is less than 0.06 [mm], the distance between the upper surface of the upper base portion 21 and the upper surface of the lower base portion 22 becomes small, and the number of particles increases, which is not preferable. When H1 exceeds 0.12 [mm], the rigidity of the upper base 21 is insufficient, and good flatness of the object to be adsorbed cannot be ensured.

  When H2 is less than 0.15 [mm] or H1 / H2 is greater than 0.60, the volume of the space surrounded by the vacuum suction member 1 and the object to be adsorbed that is supported so as to contact the plurality of protrusions 2 Is reduced, and the vacuum response of the vacuum suction member 1 is lowered, which is not preferable. When H2 exceeds 0.40 [mm], or when H1 / H2 is less than 0.30, the rigidity of the lower base 22 is insufficient, and good flatness of the object to be adsorbed cannot be ensured.

(Production method)
A substantially disk-shaped molded body made of silicon carbide was produced, and the molded body was sintered in an Ar gas atmosphere at 1900 to 2100 [° C.] to produce a substantially disk-shaped silicon carbide sintered body. The plurality of base portions 20 are formed by subjecting the upper surface of the silicon carbide sintered body to grinding, sandblasting, electric discharge machining, or the like. Next, the protective layer 24 made of a silicon carbide film is formed on the substrate 10 according to chemical vapor deposition (CVD), physical vapor deposition (PVD), plating, vapor deposition, plasma ion implantation or ion plating. Are formed to cover the upper surface and the surface of the base 20. Then, the protective layer 24 is subjected to grinding, sandblasting, electric discharge machining or the like so that at least the top surface of the protrusion 2 is flat.

(how to use)
A flat object to be adsorbed such as a semiconductor wafer is supported by the vacuum adsorbing member 1 so as to contact each of the plurality of protrusions 2. The air in the space defined by the vacuum suction member 1 and the object to be adsorbed is sucked by a vacuum suction device such as a vacuum pump connected to a vacuum suction path formed in the base body 10, so that the suction force is increased. The object to be adsorbed is adsorbed to the vacuum adsorbing member 1.

(Example)
A substantially disc-shaped substrate 10 having a diameter of 300 [mm] was produced. The plurality of protrusions 2 are arranged so as to form triangular lattice points, and the distance between them is designed to be 2.0 [mm]. The silicon carbide film constituting the protective layer 24 was formed on the upper surface of the substrate 10 and the surface of the base 20 so as to have a thickness of 60 [μm] at 1300 [° C.] according to the chemical vapor deposition method.

  The lower base portion 22 was formed in a substantially hexagonal column shape, and the upper base portion 21 was formed in a substantially cylindrical shape. A plurality of combinations shown in the white column of Table 1 were adopted as combinations of the diameter R1 of the circle forming the lower end contour of the upper base 21 and the diameter R2 of the circumscribed circle of the upper end contour of the lower base 22. The combinations shown in the white column of Table 2 were adopted as combinations of the height H1 of the upper base 21 and the height H2 of the lower base 22. Table 1 shows the ratio of the two diameters (R1 / R2). Table 2 shows the two height ratios (H1 / H2).

  R1 in the white column of Table 1 is included in the range of 0.15 to 0.30 [mm], R2 is included in the range of 0.25 to 0.60 [mm], and the diameter ratio (R1 / R2 ) Is included in the range of 0.30 to 0.60. H1 in the white column of Table 2 is included in the range of 0.06 to 0.12 [mm], H2 is included in the range of 0.15 to 0.40 [mm], and the height ratio (H1 / H2) is included in the range of 0.30 to 0.60.

  However, it is not practical to employ all combinations of (R1, R2, H1, H2). Therefore, only for the three combinations of (R1, R2) = (0.17, 0.30), (0.17, 0.40) and (0.17, 0.55), A combination of 23 white columns (H1, H2) was employed to produce 69 vacuum suction members of the examples. In addition, only for the three combinations of (H1, H2) = (0.06, 0.20), (0.09, 0.20) and (0.12, 0.20), Except for the above three combinations, 22 combinations of white columns (R1, R2) were employed to produce 66 vacuum suction members of Examples.

  Then, the vacuum responsiveness of each of the 135 vacuum suction members and the flatness of the object to be adsorbed were measured. The vacuum responsiveness is a vacuum suction device (vacuum pump) in which a silicon wafer with a flatness of 0.4 mm, curved in a convex shape around the center of the back surface with a diameter of 300 mm, is placed in contact with the pins and connected to the exhaust port. Was operated to generate a vacuum of −95 kPa, and the wafer was adsorbed to the substrate holding member. At this time, the arrival time until the entire surface was sucked was measured as the arrival time until the suction holding state. At this time, when the arrival time was 1 second or less, the vacuum response was evaluated as good, whereas when it was 1 second or more, the vacuum response was evaluated as poor. The flatness is determined by measuring the flatness of the wafer surface after the entire surface adsorption with a laser interference type shape measuring machine (MARK-GPI-XPS manufactured by Zygo), and when the thickness is 1 μm or less, the flatness is evaluated as good. The above cases were evaluated as poor flatness. As a result, the vacuum responsiveness and the flatness of the object to be adsorbed of the vacuum adsorbing members of all the examples were good.

(Comparative example)
The lower base 22 and the upper base 21 were formed in a substantially frustum shape. For three combinations of (R1, R2) = (0.17, 0.30), (0.17, 0.40) and (0.17, 0.55), (H1, H2) = ( Nine combinations of 0.06, 0.20), (0.09, 0.20), and (0.12, 0.20) were employed to produce nine vacuum suction members of comparative examples. . R2 in the comparative example represents a diameter forming the upper end contour of the lower base portion 22.

  The lower base portion 22 was formed in a substantially hexagonal column shape, and the upper base portion 21 was formed in a substantially cylindrical shape. A plurality of combinations shown in the gray column of Table 1 are adopted as a combination of R1 and the diameter R2 forming the upper end contour of the lower base 22, and a plurality of combinations shown in the white column of Table 2 are combined as H1 and H2. A combination was adopted. Furthermore, a plurality of combinations shown in the white column of Table 1 were adopted as combinations of R1 and R2, and a plurality of combinations shown in the gray column of Table 2 were adopted as combinations of H1 and H2.

  However, only for the two combinations (R1, R2) = (0.17, 0.30) and (0.17, 0.55), the combinations of 49 gray columns in Table 2 (H1, H2 ) Was used to produce 98 vacuum suction members of comparative examples. Also, each of the 36 combinations of gray columns in Table 1 is adopted only for the two combinations of (H1, H2) = (0.06, 0.20) and (0.12, 0.20). As a result, 72 vacuum suction members according to Examples were manufactured.

  Then, the vacuum responsiveness and the flatness of the object to be adsorbed of each of the 179 comparative vacuum suction members were measured. As a result, at least one of the vacuum responsiveness and the flatness of the object to be adsorbed of any of the vacuum adsorption members of the comparative examples was defective. In particular, in the vacuum suction member of the comparative example in which the combination of (R1, R2, H1, H2) marked with “*” in Table 1 or Table 2 is adopted, the space is narrow, so the vacuum response The sex was poor. In the vacuum suction member of the comparative example in which the combination of (R1, R2, H1, H2) marked with “**” in Table 1 or Table 2 is employed, the rigidity of the protrusion 2 is insufficient. The flatness of the object to be adsorbed was poor.

DESCRIPTION OF SYMBOLS 1 ... Vacuum adsorption member, 2 ... Protrusion, 10 ... Base | substrate, 20 ... Base, 21 ... Upper base, 22 ... Lower base, 24 ... Protective layer.

Claims (2)

A base, and a plurality of protrusions formed on the surface of the base, wherein the protrusion includes a base made of a silicon carbide sintered body and a silicon carbide film formed along the surface of the base. In the vacuum suction member constituted by the protective layer,
The base is constituted by a lower base portion having a regular prismatic shape or a regular truncated pyramid shape, and a columnar or truncated cone-shaped upper base portion projecting upward from an upper end of the lower base portion,
The ratio (R1 / R2) of the diameter R1 of the circle forming the lower end contour of the upper base to the diameter R2 of the circle circumscribing the regular polygon forming the upper end contour of the lower base is included in the range of 0.30 to 0.60. The vacuum suction member, wherein a ratio (H1 / H2) of the height H1 of the upper base to the height H2 of the lower base is included in a range of 0.30 to 0.60.   2. The vacuum suction member according to claim 1, wherein central axes of the lower base and the upper base are common.