WO2017086333A1

WO2017086333A1 - Vacuum chuck

Info

Publication number: WO2017086333A1
Application number: PCT/JP2016/083923
Authority: WO
Inventors: 菊地　真哉; 教夫小野寺
Original assignee: 日本特殊陶業株式会社
Priority date: 2015-11-19
Filing date: 2016-11-16
Publication date: 2017-05-26
Also published as: JPWO2017086333A1; CN107408530A; TW201727815A

Abstract

Provided is a vacuum chuck that allows a region, where flatness is secured, to be expanded in a warped or undulated substrate such as a wafer when the substrate is held by vacuum. An annular recess 10 recessed annularly around a communication path 102 is formed at the surface of a base substance 1. The annular recess 10 is provided with an annular seal member 2. The seal member 2 has as a part thereof a second element 22 formed to protrude upward from the annular recess 10 above an abutment position against a substrate at the surface of the base substance 1 (or a vacuum plane defined by them). The seal member 2 has such elasticity that the second element 22 can be inclined to the same height as an abutment position against a wafer W at the surface of the base substance 1 so that the gap 20 between the second element 22 and a first element 21 is reduced.

Description

Vacuum chuck

The present invention relates to a vacuum chuck which holds a substrate such as a wafer by suction on a surface of the substrate by a negative pressure formed through a communication path formed in the substrate.

There has been proposed a vacuum chuck provided with a skirt-like seal member made of an elastic material (for example, rubber) and formed so as to gradually spread outward from the bottom to the top at the outer edge of the substrate (see Patent Document 1) ). There has been proposed a vacuum chuck having a configuration in which a seal member is fixed to a plate-like member, and a plurality of the plate-like members are removably fixed to a base (see Patent Document 2).

According to the vacuum chuck having the above configuration, even if the wafer is warped, undulations or steps are present, the upper end of the seal member is brought into contact with the wafer over its entire circumference, and a sealed area is formed in the gap between the wafer and the suction surface. It is formed. For this reason, the influence of the gap originally generated between the substrate and the substrate due to the warpage of the wafer or the like is eliminated, and the wafer is reliably held by suction with the sealed region as a negative pressure.

Japanese Patent Application Laid-Open No. 07-308856 JP, 2010-153419, A

However, the flatness may not be secured for the area on the outer side of the contact point with the seal member and the contact point (for example, the contact point on the outermost side) in the wafer. There is room for improvement from the viewpoint of the effective use of wafers such as chip production.

Therefore, it is an object of the present invention to provide a vacuum chuck capable of expanding a region in which the flatness of a substrate is secured when suction-holding a substrate such as a wafer having warpage or waviness.

The present invention comprises a base on which a communication path is formed, and a negative pressure region is formed between the surface of the base and the substrate through the communication path, whereby the substrate is adsorbed and held on the surface side of the base. The present invention relates to a vacuum chuck configured as follows.

In the vacuum chuck according to the first aspect of the present invention, an annular recess is formed on the surface of the base to surround the communication path, and a seal member made of an annular elastic material is disposed in the annular recess. It is characterized in that a part of the member protrudes from an adsorption plane of the base and is elastically deformable.

According to the vacuum chuck of the first aspect of the present invention, when the substrate is placed on the surface side of the substrate, even if part of the seal member is elastically deformed and the substrate is warped or undulated, The part can be brought into contact with the substrate over the entire circumference or almost the entire circumference. In addition, as a curvature aspect of a board | substrate, the aspect which the said board | substrate deform | transforms into a bowl shape or dome shape is mention | raise | lifted. Aside from the convexly convex deformation in which the central portion of the substrate is above the peripheral portion, the concaved deformation in which the central portion is lower than the peripheral portion is also included. Then, the space (inner space) enclosed by the substrate, the base body, and the seal member is vacuum suctioned through the communication path, thereby forming a negative pressure region in the inner space, and the part of the seal member Further, it is elastically deformed to the same height as the adsorption surface of the substrate (virtual plane including the point or the surface of the upper end of the structure formed on the surface of the substrate). As a result, the substrate can be brought into contact entirely with the structure formed on the surface of the substrate or the contact point with them, and the area of the substrate where the flatness is secured can be expanded.

In the vacuum chuck according to the first aspect of the present invention, the seal member is inclined such that at least a portion of the annular first element disposed in the annular recess protrudes above the suction plane from the annular recess. And an annular second element extending in a vertical direction, wherein the second element is configured to be elastically tiltable to the same height as the adsorption plane on the surface of the base.

According to the vacuum chuck of the configuration, the inner space is vacuum-sucked through the communication path, whereby a negative pressure region is formed in the inner space, and the second element which is a part of the seal member is elastically inclined. It has the same height as the adsorption surface of the substrate so as to narrow the gap present between the first element. As a result, the substrate can be brought into contact entirely with the structure formed on the surface of the substrate or the contact point with them, and the area of the substrate where the flatness is secured can be expanded.

In the vacuum chuck according to the second aspect of the present invention, an annular recess is formed on the surface of the base to surround the communication path, and a seal member made of an annular elastic material is disposed in the annular recess. A lower first element arranged to be received in the annular recess, and an upper end of which one end or proximal end is fixed or connected to the first element and abuts against the substrate at the other end A second element, wherein the other end of the second element is located above the suction plane in a state where the substrate is not held by suction.

According to the vacuum chuck of the second aspect of the present invention, when the substrate is placed on the surface side of the substrate, at least the second element of the seal member is elastically deformed to cause the substrate to warp or swell. However, the other end portion (contact portion) of the second element can be brought into contact with the substrate over the entire circumference or substantially the entire circumference. Then, the space (inner space) enclosed by the substrate, the base body, and the seal member is vacuum suctioned through the communication path to form a negative pressure region in the inner space, and at least the second of the seal members is formed. The element is further elastically deformed to the same height as the adsorption surface of the substrate. As a result, the substrate can be brought into contact entirely with the structure formed on the surface of the substrate or the contact point with them, and the area of the substrate where the flatness is secured can be expanded.

In the vacuum chuck of the second aspect of the present invention, preferably, the seal member is configured such that a gap is present between the first element and the second element. In the vacuum chuck of the second aspect of the present invention, preferably, the seal member is configured such that a gap opened to the outside is present between the first element and the second element.

According to the vacuum chuck of the above configuration, the substrate is formed entirely on the surface of the substrate as described above by elastically changing the seal member so that the form of the gap between the first element and the second element changes. It is possible to abut on the structure or the contact point with the same, and the expansion of the area where the flatness is secured in the substrate is achieved.

FIG. 1 is a top view of a vacuum chuck according to an embodiment of the present invention. II-II sectional view taken on the line of FIG. Explanatory drawing regarding the function of the vacuum chuck as one embodiment of the present invention. Explanatory drawing regarding the other Example of a sealing member. Explanatory drawing regarding the other Example of a sealing member. Explanatory drawing regarding the other Example of a sealing member. FIG. 5 is a top view of a vacuum chuck as another embodiment of the present invention.

(Constitution)
A vacuum chuck as an embodiment of the present invention shown in FIGS. 1 and 2 includes a base 1 made of a substantially disc-shaped ceramic sintered body. The base 1 is produced by firing a formed body of a raw material powder whose main raw material is a ceramic powder such as silicon carbide, aluminum nitride, alumina or silicon nitride and performing necessary processing.

In addition to the communication path 102 (through hole), a lift pin through hole 104 through which a lift pin (not shown) for moving the wafer W (substrate) up and down is inserted is formed in the base 1. An annular recess 10 (for example, a depth of 1 to 10 mm and a width of 1 to 10 mm) which is annularly recessed and surrounds the communication path 102 is formed on the surface of the base 1. An annular seal member 2 is disposed in the annular recess 10.

The base 1 is formed with an annular projecting portion 12 (for example, a height of 30 to 200 μm) projecting annularly surrounding the annular recess 10. The upper end portion of the annular convex portion 12 constitutes a “contact point with the wafer W” in the base 1. Besides, on the suction surface of the substrate 1, a plurality of substantially cylindrical, substantially hemispherical or substantially truncated cone shaped pins (not shown (for example, height 30 to 200 [μm])) protruding from the suction surface are triangular. It may be regularly arranged and formed, such as lattice shape, square lattice shape or concentric shape. The upper end portions of the plurality of pins constitute a “contact point with the wafer W” in the base 1 and define an adsorption plane. Although FIG. 2 shows that the upper end surface or the surface of the substrate 1 is a flat surface, in practice a discrete surface constituted by the upper end surface of the annular convex portion 12 and the upper end surface of each pin Is a set of

The sealing member 2 is an annular member, and is made of an elastic material such as urethane or fluorine rubber. The seal member 2 includes a lower first element 21 and an upper second element 22. In the sealing member 2, the lower first element 21 is disposed so that the whole thereof fits in the annular recess 10. In the seal member 2, the upper second element 22 has one end or proximal end fixed or connected to the first element 21, and abuts the substrate (wafer W) at the other end. The other end of the second element 22 is located above the suction plane when the substrate (wafer W) is not held by suction. A material having a hardness of 0 to 60 is employed as a material forming the second element 22. The hardness of the material constituting the first element 21 may be the same as or different from the hardness of the material constituting the second element 22. Hardness is measured using a durometer based on JIS K6253: 2012.

The seal member 2 includes a substantially trapezoidal first element 21 in a cross sectional view and a second element 22 located in the upper part of the first element 21 and having a substantially L shape in a cross sectional view (FIG. 2 reference). The second element 22 has a gap 20 with respect to the first element 21 and is connected to the first element 21 at its proximal end. For example, in a cross sectional view, the length L of the second element 22 is included in the range of 2.0 to 20 mm, and the thickness T of the second element 22 is in the range of 0.1 to 2.0 mm The seal member 2 may be configured such that the protrusion height H of the second element 22 is included in the range of 1.0 to 9.0 [mm] with reference to the suction plane.

The second element 22 is configured to be elastically tiltable to the same height as the contact portion (suction plane) with the wafer W on the surface of the substrate 1 so as to narrow the gap 20 present between the second element 22 and the first element 21. (See Figure 3). When the second element 22 transitions from a loaded state to a released state, the seal member 2 is required to have elasticity to restore its original posture or configuration. Taking this point into consideration, the hardness of the material constituting the seal member 2 and the thickness of the bending point or proximal end of the second element 22 are designed. Between the side surface 202 of the seal member 2 and the inner side surface of the annular recess 10, a gap having an opening on the surface side of the base 1 is formed. The seal member 2 is configured such that the upper inclined surface of the second element 22 is inclined upward continuously from the flat upper end surface 204 of the seal member 2.

(function)
According to the vacuum chuck having the above configuration, when the wafer W is mounted on the front surface side of the substrate 1, even if the second element 22 which is a part of the sealing member 2 is warped or undulated by the wafer W, all The wafer W can be in contact with the wafer W all around or around the entire circumference. Then, a space (inner space) surrounded by the wafer W, the base 1 and the seal member 2 is vacuum suctioned through the communication path 102. As a result, a negative pressure region is formed in the inner space, and the seal member 2 is elastically deformed so that the second element 22 is elastically tilted, and has the same or substantially the same height as the suction plane of the substrate 1. (See Figure 3). As a result, the wafer W can be entirely brought into contact with the suction surface of the substrate 1, and further, the area of the wafer W where the flatness is secured can be expanded.

(Other embodiments of the present invention)
The shape of each of the sealing member 2 and the annular recess 10 may be variously changed. For example, as shown in FIG. 4, the seal member 2 may be torus shaped. The seal member 2 has a substantially circular shape in a cross sectional view, and the upper end portion of a portion (corresponding to the second element 22) protruding above the suction plane of the base 1 is in contact with the substrate (wafer W). The contact part which contacts is comprised. As also shown in FIG. 4, the annular recess 10 may be formed to have a generally trapezoidal cross-section with the upper bottom on the upper side. In other words, the inner side surface of the annular recess 10 may be inclined toward the bottom of the annular recess 10. According to such a configuration, since the width on the bottom side of the annular recess 10 is larger than the width on the upper side in the cross sectional view, the situation where the seal member 2 is detached from the annular convex portion 10 is prevented . The cross-sectional shape of the sealing member 2 may be a bellows shape (not shown) in which the axial direction extends in the vertical direction. The cross-sectional shape of the annular recess 10 is a substantially trapezoidal shape, and the seal member 2 has an annular protrusion, such as a shape (not shown) having one or more protrusions projecting inward from the lower end position to the upper end position. It may be of any shape that can prevent it from coming off part 10.

As shown in FIG. 5, the appearance of the seal member 2 is formed in a torus shape as in FIG. 4, but in a cross sectional view, the lower semicircular arc first element 21 and the upper semicircular arc And the second element 22 of In other words, the seal member 2 shown in FIG. 5 is formed of a hollow member. Although not shown, the hollow member may be configured of a U-shaped first element opened upward and a U-shaped second element opened downward.

As shown in FIG. 6, the substantially rectangular shape in which the first element 21 has a vertically elongated substantially rectangular cross section, and the second element 22 continuously extends obliquely upward from the upper portion of the first element 21. The seal member 2 may be formed to have a cross section of The seal member 2 may have a substantially U-shape (a shape in which the L-shape is turned upside-down) in a cross sectional view, and the annular recess 10 has a vertically elongated rectangular upper end in which the seal member 21 is accommodated. In the part, a horizontally long rectangular shape extending in the lateral direction is continuous.

For example, the seal member 2 may have no flat upper end surface 204 (see FIG. 2), and the upper end surface may be formed only by an inclined surface. The upper inclined surface of the second element 22 may not be inclined at a uniform angle, but may be formed so that the inclination angle gradually decreases or increases. The second element 22 constituting the seal member 2 is inclined to the upper side (outer edge side) and upper side of the base 1 (see FIG. 2), but may be inclined to the upper side (central side) and upper side of the base 1 . The inner side surface 202 of the seal member 2 and the inner side surface of the annular recess 10 may be in contact with each other, and the gap between the two may not be provided.

Although each of the annular recess 10, the seal member 2 and the annular protrusion 12 in the vacuum chuck of the above embodiment is formed in a substantially annular shape, it may be an elliptical annular shape, a rectangular annular shape, a frame shape or a large number according to the shape of the wafer W. The shape may be changed into any shape as long as it is an annular shape such as a rectangular annular shape.

The annular convex portion 12 may be omitted in the above embodiment. By correcting the warpage or distortion or the like of the inner area surrounded by the contact portion with the seal member 10 to be flat, the warpage or the like of the outer area outside the inner area can also be corrected to be flat.

In the above embodiment, an outer annular recess 10 'is formed on the surface of the base 1 in place of the annular projection 12 as shown in FIG. 7, and an outer seal member 2' having the same configuration as that described above. May be arranged. That is, an outer seal is formed on the surface of the base 1 with a plurality of annular recesses 10, the seal member 2 is disposed in each of the plurality of annular recesses 10, and is disposed in the outer annular recess 10 'in which the inner annular recess 10 is present. At least a part of the second element 22 (see FIG. 2) constituting the member 2 ′ may form the annular convex portion. The base 1 may have a communication passage 102 'formed between the inner seal member 2 and the outer seal member 2'.

According to the vacuum chuck having the above configuration, when the wafer W is mounted on the front surface side of the substrate 1, the second element 22 which is a part of the inner seal member 2 and the second which is a part of the outer seal member 2 ′ The element is elastically deformed by receiving a load from the wafer W. Therefore, even if the wafer W is warped or undulated, each of the second elements can be brought into contact with the wafer W over the entire circumference or substantially the entire circumference. The space (inner space) enclosed by the base 1 and the inner seal member 2 is vacuum suctioned, and the wafer W, the base 1, the inner seal member 2 and the outer seal member 2 ′ are further passed through the outer communication path 102 ′. The annular space (outer space) enclosed by the and is evacuated. As a result, a negative pressure region is formed in the inner space, and the second element 22 of the inner seal member 2 and the second element of the outer seal member 2 ′ are further elastically deformed to the same height as the suction surface of the substrate 1. (See Figure 3). As a result, the wafer W can be entirely brought into contact with the contact portion of the surface of the substrate 1, and further, the area of the wafer W where the flatness is secured can be expanded.

Since the inner seal member 2 is installed in addition to the outer seal member 2 ', not only the wafer W having a relatively large diameter (for example, 12 inches in diameter) corresponding to the outer seal member 2' but also the inner seal member 2 The wafer W having a relatively small diameter (for example, 8 inches in diameter) can also be vacuum suctioned. In addition, even if the wafer W is extremely warped to such an extent that the outer seal member 2 ′ can not abut the entire periphery of the wafer W, the inner seal member 2 is reliably abutted against the wafer W The pressure in the inner space is corrected so that the wafer W becomes flat. Thereby, the outer seal member 2 ′ can be brought into contact with the wafer W over the entire circumference, so that the flatness of the wafer W can be improved by reducing the pressure in the outer space.

In the vacuum chuck of the embodiment, the annular convex portion 12 may be omitted.

1 .. base body, 2. seal member, 10. annular recess, 12. annular convex portion, 20. gap between first and second elements, 21. first element, 22. second element, 102 communication path, 104. Through holes for lift pins.

Claims

The substrate is provided with a communication path, and a negative pressure region is formed between the surface of the substrate and the substrate through the communication path, and thus the substrate is adsorbed and held on the surface side of the substrate. Vacuum chuck, and
An annular recess is formed on the surface of the base to surround the communication path;
A seal member made of an annular elastic material is disposed in the annular recess,
A vacuum chuck characterized in that a part of the seal member protrudes from an adsorption plane of the base and is elastically deformable.
In the vacuum chuck according to claim 1,
The seal member includes an annular first element disposed in the annular recess, and an annular second element extending at an angle so that at least a portion of the seal member protrudes upward from the suction plane. And the second element is elastically tiltable to the same height as the suction plane on the surface of the substrate.
The substrate is provided with a communication path, and a negative pressure region is formed between the surface of the substrate and the substrate through the communication path, and thus the substrate is adsorbed and held on the surface side of the substrate. Vacuum chuck, and
An annular recess is formed on the surface of the base to surround the communication path;
A seal member made of an annular elastic material is disposed in the annular recess,
The sealing member is fixed or connected to the lower first element disposed so as to be accommodated in the annular recess, and one end or proximal end thereof against the first element, and abuts the substrate at the other end An upper second element,
A vacuum chuck characterized in that the other end of the second element is located above the suction plane when the substrate is not held by suction.
In the vacuum chuck according to claim 3,
A vacuum chuck characterized in that the seal member is configured such that a gap exists between the first element and the second element.
In the vacuum chuck according to claim 4,
A vacuum chuck characterized in that the seal member is configured such that there is a gap opened to the outside between the first element and the second element.