JP2018037469A - Vacuum suction member - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vacuum suction member that can further improve flatness when sucking and holding a substrate such as a wafer whose degree of deflection or warp is large.SOLUTION: A vacuum suction member is configured such that: in a first stage where an upper end of a movable member 2 is at a first position above protrusion parts 11, 12, downward force is exerted on a wafer W at a location corresponding to an upper end opening part of a first sub-airflow passage 21; and in a second stage where the upper end of the movable member 2 is at a second position below or level with the protrusion parts 11, 12, downward force is exerted with a time difference, on the wafer W at a location corresponding to an upper end opening part of a second airflow passage 102. As a result, the wafer W is sucked and held on the base body 1 such that distortion or heaving of the wafer W is sequentially reformed.SELECTED DRAWING: Figure 4B

Description

  The present invention relates to a technique for holding a substrate such as a wafer by vacuum suction.

  It has been proposed to provide a substrate adsorbing device that can adsorb and fix even a warped or wavy substrate in a flat state (for example, see Patent Document 1).

  The substrate suction device includes a main body in which a vacuum space is formed, a communication hole that communicates between the vacuum space and the outside and extends in a direction perpendicular to the support surface, and a suction portion. It has. The suction portion includes a support portion that is slidably and airtightly supported along the communication hole of the main body, and a suction pad that is connected to the support portion and protrudes backward from the support surface of the main body. A suction hole is formed in the support portion and the suction pad to communicate the outside and the vacuum space of the main body. As a result, the substrate can be attracted to the main body while being adsorbed by the adsorbing pad of the adsorbing portion and brought into contact with the support surface of the main body.

JP 2012-146783 A

  However, apart from the suction hole of the suction portion, a suction hole that connects the opening and the vacuum space is formed in the upper wall member of the main body. For this reason, when the vacuum space of the main body is depressurized, a force attracted to the main body side simultaneously acts on portions of the substrate corresponding to the suction portion and the opening. When the substrate is constrained by this force, there is a case where the substrate is attracted and held in the state where the bending or warping remains.

  Therefore, an object of the present invention is to provide a vacuum suction member that can further improve the flatness during suction holding of a substrate such as a wafer having a large degree of bending or warping.

  The vacuum suction member of the present invention is a vacuum suction member including a base having an upper surface and a convex portion formed on the upper surface, and the base includes a concave portion locally recessed downward from the upper surface. A first air passage that communicates with the concave portion from the outside, and a first position that is above the convex portion and a second position that is the same height as the convex portion or below the convex portion When the upper end of the movable member is movable, the movable member is disposed in the concave portion, and is disposed in a space communicating with the first air passage in the concave portion, and the upper end is below the first position. And a biasing member that biases the movable member upward, and a first sub-air passage that penetrates the movable member vertically and communicates with the first air passage is formed inside the movable member. , An opening provided on the upper surface of the base body extending from the recess A second air passage that communicates with the outside is formed inside the base, communicates with the first sub-air passage, and is shut off from the second air passage when the movable member is in the first position. On the other hand, a second sub-air passage communicating with the second air passage when the movable member is in the second position is formed in the movable member.

  According to the vacuum suction member of the present invention, in a state where the substrate is in contact with the upper end of the movable member at the first position and at least a part of the convex portions formed on the upper surface of the base body, The first air passage is vacuumed. Thereby, the lower space of the movable member and the first sub-air passage formed in the movable member in the concave portion are depressurized, and in the first stage, the portion corresponding to the upper end opening of the first sub-air passage in the substrate. A downward force is applied. Further, a downward force acts on the movable member, and the movable member descends against the urging force of the urging member, so that the substrate also descends to follow this. When the upper end of the movable member reaches the second position, the second sub-air passage formed in the movable member and the second air passage formed in the base body communicate with each other. Thus, in the second stage following the first stage, the first air passage is depressurized via the second sub-air passage, and a downward force is applied to a portion of the substrate corresponding to the upper end opening of the second air passage. Act.

  That is, according to the vacuum suction member of the present invention, the substrate is moved downward with a time difference to a position corresponding to the upper end opening of the first sub-air passage of the movable member and a position corresponding to the upper end opening of the second air passage of the base. The force can be applied to. As a result, unlike the case where a downward force is simultaneously applied to the two locations, the substrate is adsorbed and held on the base so that the bending or undulation of the substrate is sequentially corrected. The improvement of the property is achieved.

  In the vacuum suction member, it is preferable that a plurality of the concave portions in which the movable member and the urging member are disposed are formed on the base.

  According to the vacuum suction member of the said structure, after making downward force act on several places of a board | substrate in the 1st step, it differs from the said several places of the board | substrate in the 2nd step following this. A downward force can be applied to the part. As a result, the substrate is attracted and held on the base body so that the bending or undulation of the substrate is sequentially corrected, so that the flatness of the substrate can be improved.

  In the vacuum suction member, it is preferable that the opening is formed inside an annular region including a plurality of the recesses on the upper surface of the base.

  According to the vacuum suction member of the said structure, after making downward force act on several places in the cyclic | annular area | region (for example, peripheral area | region of a board | substrate) of the board | substrate corresponding to the said cyclic | annular area | region in the 1st step, In the subsequent second stage, a downward force can be applied to one or more locations in the region inside the annular region of the substrate. As a result, the substrate is attracted and held on the base so that the bending or undulation of the substrate is sequentially corrected from the outside to the inside, so that the flatness of the substrate can be improved.

  In the vacuum suction member of the present invention, when the upper end of the movable member is in the second position, the second air passage formed in the base in the circumferential direction of the movable member, and the interior of the movable member It is preferable that the movable member and the concave portion are configured so that the second sub-air passage formed in is aligned.

  According to the vacuum suction member having such a configuration, it is possible to avoid a situation in which the positions of the second air passage of the base and the second sub air passage of the movable member are shifted in the circumferential direction of the movable member. For this reason, the second ventilation path of the base and the second auxiliary ventilation path of the movable member can be reliably communicated with each other with the upper end of the movable member being in the second position.

  In the vacuum suction member, the movable member includes a columnar first element and a second element protruding in a radial direction from a part of a side surface of the first element, and the concave portion is the movable element. A cylindrical first recess corresponding to the first element of the member, and a second recess that is continuous with the first recess and contacts the second element of the movable member on both sides in the circumferential direction. It is preferable to be configured.

  According to the vacuum suction member configured as described above, the second element of the movable member abuts on the second concave portion of the base, so that the position of the second air passage of the base and the second sub-air passage of the movable member is the position of the movable member. A situation in which the circumferential direction of the first element is shifted is avoided. For this reason, the second ventilation path of the base and the second auxiliary ventilation path of the movable member can be reliably communicated with each other with the upper end of the movable member being in the second position.

BRIEF DESCRIPTION OF THE DRAWINGS Structure explanatory drawing of the vacuum suction member as one Embodiment of this invention. Sectional drawing along the II-II line of FIG. Structure explanatory drawing of a movable member and a recessed part. Explanatory drawing regarding the 1st step of the vacuum suction of a wafer. Explanatory drawing regarding the 2nd step of the vacuum suction of a wafer. Explanatory drawing regarding the vacuum suction holding | maintenance state of a wafer. The structure explanatory view of the movable member of the modification of the present invention. The structure explanatory view of the movable member of the modification of the present invention. The structure explanatory view of the vacuum adsorption member of the modification of the present invention.

(Constitution)
A vacuum suction member as an embodiment of the present invention shown in FIGS. 1 and 2 includes a disk-shaped base 1 for holding the wafer W by suction on the upper surface side, and a recess formed in the base 1. The movable member 2 is arranged in a state of being movable up and down in 10 and a lower space communicating with the first air passage 101 in the recess 10, and the upper end of the movable member 2 is below a first position (described later). And a biasing member 4 that biases the movable member 2 upward.

  On the upper surface of the base body 1, a plurality of pin-shaped convex portions 11 and a substantially annular annular convex portion 12 extending along the outer peripheral edge of the base body 1 so as to surround the plurality of convex portions 11 are provided. ing. In FIG. 1 and FIG. 2, the constituent elements such as the convex portion 11 and the annular convex portion 12 are deformed to clarify the configuration of the vacuum suction member. The ratio of the distance between each other is different from the actual one.

  The plurality of convex portions 11 are arranged concentrically around the center of the base body 1 with a constant interval in the circumferential direction and the radial direction. The plurality of convex portions 11 are regularly arranged in other forms such as a triangular lattice shape and a square lattice shape, and are locally irregular so that a difference in density is locally generated in the circumferential direction or the radial direction. May be arranged. The interval or pitch of the convex portions 11 is designed to be, for example, 8 [mm] or less, preferably 6 [mm] or less, and more preferably 4 [mm] or less. The protruding amount of the convex portion 11 from the upper surface of the base body 1 is designed to be included in the range of 10 to 200 [μm], for example.

  The convex portion 11 has a columnar shape such as a columnar shape or a prismatic shape, a frustum shape such as a truncated cone shape or a truncated pyramid shape, a columnar shape with a step such that the cross-sectional area of the upper portion is smaller than the lower portion, or a frustum shape. It is formed into a shape. The diameter of the upper end portion (contact portion with the wafer W) of the convex portion 11 is designed to be 500 [μm] or less. The surface roughness Ra of the upper end portion (contact portion with the wafer W) of the convex portion 11 is designed to be included in the range of 0.01 to 0.50 [μm].

  The annular convex portion 12 may be formed so that the upper end thereof is at the same height as the upper end of the convex portion 11 or may be formed at a position lower than the upper end of the convex portion 11. The cross-sectional shape of the annular convex portion 12 along the radial direction of the substrate 1 may be various shapes such as a rectangular shape, a trapezoidal shape, a semicircular shape, or a semielliptical shape.

  The base body 1 is formed with a concave portion 10 that is locally depressed downward from the upper surface. Inside the base 1, a first air passage 101 communicating with the recess 10 from the outside through an opening at the center of the bottom surface of the recess 10 and an opening provided on the top surface of the base 1 extending from the recess 10 are provided. And a second air passage 102 communicating with the outside. The first air passage 101 is connected to a vacuum suction device (not shown). The second air passage 102 extends from the recess 10 in the lateral direction along the upper surface of the base body 1 and then extends upward to the upper surface of the base body 1, but extends obliquely upward from the recess 10, etc. The extending aspect may be variously changed. The substrate 1 may be formed with a plurality of through holes (not shown) through which lift pins for adjusting the distance between the upper surface of the substrate 1 and the lower surface of the wafer W are moved up and down.

  In the present embodiment, six concave portions 10 that are recessed downward in a substantially cylindrical shape are arranged at equal intervals in the circumferential direction in the annular region along the inside of the annular convex portion 12. That is, the six recesses 10 are arranged so as to have six-fold rotational symmetry with respect to the center of the base 1. Each opening of the six second air passages 102 is disposed at a location spaced radially inward from each of the six recesses 10. That is, the respective openings of the six second air passages 102 are arranged so as to have six-fold rotational symmetry with respect to the center of the base 1 in the inner region of the annular region.

  Note that the number and arrangement of the recesses 10, the number of the second air passages 102 corresponding to each recess 10 and the number of the openings, and the arrangement of the openings are variously changed in different forms from the above embodiment. Also good. For example, at least one opening of the second air passage 102 may be disposed in the annular region, and at least one recess 10 may be disposed in the inner region surrounded by the annular region.

  The movable member 2 is made of, for example, ceramics such as silicon carbide or alumina, and is disposed in the recess 10 so that its upper end is movable up and down between a first position and a second position below the first position. Yes. The “first position” is above the convex portion 11 and the annular convex portion 12. The “second position” is the same height as the convex portion 11 and the annular convex portion 12 or below the convex portion 11 and the annular convex portion 12. The outer surface of the movable member 2 and the inner surface of the recess 10 have a surface roughness Ra of 0.001 to 0.2 [μm] so that airtightness is maintained when the movable member 2 moves up and down. And the clearance between the movable member 2 and the inner surface of the recess 10 is adjusted so as to be included in the range of 1 to 10 [μm].

  An airtight member such as an O-ring may be disposed on the outer surface of the movable member 2 in order to maintain airtightness with the inner surface of the recess 10. In this case, a groove 202 for mounting the airtight member is formed on the outer surface of the movable member 2 over the entire circumference of the movable member 2 as shown in FIG. 5, and the airtight member is disposed in the groove 202. The According to this, even if the clearance between the outer side surface of the movable member 2 and the inner side surface of the recess 10 is larger than 10 [μm], airtightness can be maintained.

  Inside the movable member 2, a first sub-air passage 21 that penetrates the movable member 2 in the vertical direction and communicates with the first air passage 101 is formed. The movable member 2 communicates with the first sub-air passage 21 and is blocked from the second air passage 102 when the movable member 2 is in the first position, while the movable member 2 is in the second position. In some cases, a second sub-air passage 22 communicating with the second air passage 102 is formed. The second sub-air passage 22 branches from the first sub-air passage 21 in the radial direction of the movable member 2 and extends to the outer surface of the movable member 2.

  As shown in FIG. 3, the movable member 2 protrudes in a radial direction from a columnar first element 2A and a part of a side surface of the first element 2A, and extends in the axial direction of the first element 2A. And a second element 2B extending over the entire length. The second element 2B may protrude in the radial direction not only at one place but also at a plurality of places in the circumferential direction of the first element 2A. The second element 2B may project locally in the radial direction at one or a plurality of locations, instead of the total length in the axial direction of the first element 2A. The second element 2B is on the opposite side of the second sub-air passage 22 with respect to the central axis of the first element 2A. The position of the second element 2B with respect to the second sub-air passage 22 may be variously changed.

  Similarly, as shown in FIG. 3, the recess 10 is continuous with the first recess 10 </ b> A corresponding to the first element 2 </ b> A of the movable member 2 and the first recess 10 </ b> A. The second recess 10B is in contact with the two elements 2B on both sides in the circumferential direction.

  Further, as shown in FIG. 6, a groove portion 204 is formed on the outer surface of the movable member 2 over the entire circumference of the movable member 2, and an opening portion of the second sub-air passage 22 is formed on the bottom surface of the groove portion 204. May be. According to this, even if the movable member 2 rotates in the recess 10, when the upper end of the movable member 2 is in the second position, the second sub-air passage 22 and the second air passage 102 are surely connected via the groove portion 204. Can communicate with each other.

  Furthermore, as shown in FIG. 7, a groove portion 104 may be formed on the inner surface of the recess 10 over the entire circumference, and an opening portion of the second air passage 102 may be formed on the bottom surface of the groove portion 104. According to this, similarly to the embodiment shown in FIG. 6, even if the movable member 2 rotates in the recess 10, the second sub-air passage 22 and the second air passage 102 are reliably communicated with each other via the groove portion 104. Can do.

(Production method)
The vacuum suction member having the above-described configuration is manufactured by the following procedure, for example. That is, a substantially disk-shaped molded body is produced from the raw material powder, and the molded body is fired to produce a substantially disk-shaped sintered body that is the basis of the substrate 1. As the raw material powder, for example, silicon carbide having a purity of 97% or more, and mixed raw material powder to which an appropriate amount of a sintering aid is added if necessary are used. In addition, other ceramic powders such as alumina powder may be used as the raw material powder. In addition, a plurality of concave portions 10, a plurality of convex portions 11, an annular convex portion 12, a first air passage 101 and a second air passage 102 are formed on the sintered body according to an appropriate processing method such as blasting or milling. Thus, the substrate 1 is produced.

  A substantially cylindrical shaped body is produced from the same raw material powder, and the shaped body is fired to produce a substantially cylindrical sintered body that is the basis of the movable member 2. In addition, the movable member 2 is manufactured by forming the first sub-air passage 21 and the second sub-air passage 22 according to an appropriate processing method such as milling.

  Then, an urging member 4 such as a spring (for example, a coil spring or a leaf spring) is disposed with respect to the concave portion 10 of the base body 1, and the movable member 2 is further disposed or inserted. The vacuum suction member having the above-described configuration is manufactured by the above process.

(function)
According to the vacuum suction member having the above-described configuration, as shown in FIG. 4A, the upper end of the movable member 2 in the first position, and the protrusions 11 and the annular protrusions 12 formed on the upper surface of the base 1. The first air passage 101 is vacuum-sucked in a state where the wafer W is in contact with at least a part of the wafer W (see FIG. 4A / downward white arrow). Thereby, the space below the movable member 2 in the concave portion 10 and the first sub-air passage 21 formed in the movable member 2 are depressurized. In the first stage, the upper end opening of the first sub-air passage 21 is formed in the wafer W. A downward force acts on the corresponding part (see FIG. 4A / downward black arrow). Further, a downward force is applied to the movable member 2, and the movable member 2 descends against the urging force of the urging member 4, so that the wafer W also descends so as to follow this.

  Then, as shown in FIG. 4B, when the upper end of the movable member 2 reaches the second position, the second sub-ventilation path 22 formed in the movable member 2 and the second ventilation formed in the base 1. The road 102 communicates. As a result, in the second stage following the first stage, the pressure of the second air passage 102 is reduced via the second sub air passage 22, and the wafer W is moved downward with respect to the portion corresponding to the upper end opening of the second air passage. (See FIG. 4B / downward black arrow on the left).

  That is, according to the vacuum suction member having the above-described configuration, a position (annular outer region) corresponding to the upper end opening of the first sub vent path 21 of the movable member 2 and the upper end of the second vent path 102 of the wafer W are configured. A downward force can be applied to a portion corresponding to the opening (an inner region surrounded by the outer region) with a time difference. As a result, unlike the case where a downward force is applied simultaneously to the two locations, the wafer W is attracted and held on the substrate 1 so that the bending or undulation of the wafer W is sequentially corrected. As shown in FIG. 4C, the flatness of the substrate is improved.

  When the second element 2B of the movable member 2 contacts the second recess 10B of the base body 1 on both sides in the circumferential direction, the positions of the second air passage 102 of the base body 1 and the second sub air passage 22 of the movable member 2 are movable. A situation in which the circumferential direction of the first element 2A of the member 2 is shifted is avoided. For this reason, in the state where the upper end of the movable member 2 is in the second position, the second ventilation path 102 of the base 1 and the second auxiliary ventilation path 22 of the movable member 2 can be reliably communicated (see FIG. 4B).

  The movable member 2 and the concave portion 10 are not in a shape that can rotate around the axis line like a columnar shape, but when the movable member 2 is arranged in the concave portion 10 like a prismatic shape, the displacement in the circumferential direction thereof is shifted. The movable member 2 may be formed in a shape that can be prevented. Also by this, when the upper end of the movable member 2 is in the second position, the second air passage 102 of the base 1 and the second sub air passage 22 of the movable member 2 are surely positioned in the circumferential direction of the movable member 2. To be combined.

DESCRIPTION OF SYMBOLS 1 ... Base | substrate, 2 ... Moving member, 2A ... 1st element, 2B ... 2nd element, 4 ... Energizing member, 10 ... Concave part, 10A ... 1st recessed part, 10B ... 2nd recessed part, 11 ... Convex part, 12 ... An annular convex portion, 21... First sub-air passage, 22... Second sub-air passage, 101... First air passage, 102.

Claims (5)

A vacuum suction member comprising a base having an upper surface and a convex portion formed on the upper surface,
The base includes a concave portion locally recessed downward from the upper surface, and a first air passage communicating with the concave portion from the outside,
It is arranged in the recess with its upper end movable between a first position above the projection and the second position below the same height as the projection or the second position below the projection. A movable member;
An urging member disposed in a space communicating with the first air passage in the recess, and urging the movable member upward when the upper end is below the first position;
A first sub-air passage that vertically penetrates the movable member and communicates with the first air passage is formed inside the movable member;
A second air passage extending from the recess and communicating with the outside through an opening provided on the upper surface of the base is formed in the base.
When the movable member is in the second position, the second auxiliary passage is communicated with the first sub-ventilation passage, and when the movable member is in the first position, the second vent passage is blocked. A vacuum suction member, wherein a second sub-air passage communicating with the air passage is formed in the movable member. The vacuum suction member according to claim 1,
The vacuum suction member, wherein a plurality of the recesses in which the movable member and the urging member are disposed are formed on the base. The vacuum suction member according to claim 2,
The vacuum suction member, wherein the opening is formed inside an annular region including a plurality of the recesses on the upper surface of the base. The vacuum suction member according to any one of claims 1 to 3,
When the upper end of the movable member is in the second position, the second ventilation path formed in the base in the circumferential direction of the movable member and the second formed in the movable member. The vacuum suction member, wherein the movable member and the recess are configured so that the sub-air passage is aligned. The vacuum suction member according to claim 4,
The movable member is constituted by a columnar first element and a second element protruding in a radial direction from a part of a side surface of the first element,
The concave portion is continuous with the first concave portion of the columnar shape corresponding to the first element of the movable member and the first concave portion, and contacts the second element of the movable member on both sides in the circumferential direction. A vacuum suction member comprising: a second recess.