JP2020102569A - Holding table - Google Patents

Abstract

To provide a holding table with a simple structure, in which an air bite and wrinkles in a chip holding region in which a chip component to be diced is held are not caused, and a time until an adsorption completion can be reduced.SOLUTION: In a holding table 1 of an expand sheet Ws attached to a wafer ring Wr holding a chip component D to be diced, the expand sheet comprises: an external peripheral support part 2 having an adhesive first face and an adhesive second face, and supporting an outer peripheral part from a chip holding area Rd in which the chip component is held in a prescribed posture; an inner peripheral support part 3 supporting an inner peripheral part containing a chip holding region in the expand sheet in a flat posture while being contacted from the second face side; and a negative pressure suction part 4 in which the external peripheral support part and the inner peripheral support part make the region contacted to the second face of the expand sheet in a negative pressure. The external peripheral support part comprises a projection part 5 projected from the inner peripheral support part in an inner side from a region where a wafer ring is arranged.SELECTED DRAWING: Figure 1

Description

The present invention relates to a holding table that holds a stretchable expandable sheet attached to an annular wafer ring for holding a dicing chip component in a predetermined posture.

A semiconductor device has a large number of semiconductor device circuits formed on a single semiconductor wafer, is divided into individual chip parts, and the chip parts are packaged to be shipped individually as electronic parts or to electronic products. Be incorporated.

Then, one semiconductor wafer is handled while being attached and fixed to an expandable sheet (also referred to as a dicing tape) having elasticity that is attached to an annular wafer ring (also referred to as an expander ring or a dicing frame). A semiconductor wafer is diced into a large number of chip components (for example, Patent Document 1).

Then, the diced chip component is inspected after being attached to the expand sheet, and then a non-defective product is picked up and packaged (for example, Patent Documents 2 and 3).

The ring-shaped wafer ring includes one in which an expand sheet is attached and fixed to a substantially ring-shaped metal plate, and one in which the expand sheet is sandwiched and fixed by a double ring-shaped frame body such as an embroidery frame.

International Publication No. 2018/0795936 Patent No. 5917492 JP 2006-332468 A

The expanded sheet attached to the ring-shaped wafer ring loses rigidity after the wafer is diced, and slack and wrinkles easily occur. Therefore, when the expanded sheet is placed on a holding table composed of a flat surface and is attempted to be suction-held, air is trapped in the chip holding area where the diced chip parts are held (air pools that are not discharged into the contact area are generated. There is a problem that the expanded sheet cannot be held in a predetermined posture due to the occurrence of (scattering) or wrinkles remaining.

On the other hand, in the structure in which the expand sheet is pushed up in advance to apply the tension by the mechanism that raises the part corresponding to the cavity of the wafer ring above the part supporting the wafer ring, the structure or mechanism is complicated or the tension is applied. However, there was a problem that it took extra operating time.

Therefore, the present invention has been made in view of the above problems,
An object of the present invention is to provide a holding table having a relatively simple structure that does not cause air bites or wrinkles in the chip holding area where the diced chip parts are held, can shorten the time until completion of suction, and has a relatively simple structure.

In order to solve the above problems, one aspect of the present invention is
A holding table for holding a dicing chip component, an expandable sheet having elasticity attached to an annular wafer ring, in a predetermined posture,
The expand sheet has a first surface having an adhesive property for holding a chip component, and a second surface having a non-adhesive relationship in a front-back relationship with the first surface,
An outer peripheral support portion that supports the outer peripheral portion outside the chip holding area in which the chip components are held in the expand sheet from the second surface side and supports the outer peripheral portion in a predetermined posture;
An inner peripheral support portion that supports the inner peripheral portion of the expandable sheet including the chip holding area from the second surface side in a flat posture,
A negative pressure suction portion that applies a negative pressure to a region where the outer peripheral support portion and the inner peripheral support portion contact the second surface of the expanded seat,
The outer peripheral support portion is characterized in that it is provided with a protruding portion that protrudes more than the inner peripheral support portion inside the region where the wafer ring is arranged.

According to the present invention, air catching or wrinkling does not occur in the chip holding region in which the diced chip component is held, and the time until the suction is completed can be shortened. Furthermore, a holding table having a relatively simple structure can be realized.

It is a perspective view showing an example of the form which embodies the present invention. It is sectional drawing which shows the principal part of an example of the form which embodies this invention. It is a perspective view which shows the modification of the form which embodies this invention.

Hereinafter, modes for carrying out the present invention will be described with reference to the drawings.

In the following description, the three axes of the orthogonal coordinate system are X, Y, and Z, the horizontal direction is expressed as the X direction and the Y direction, and the direction perpendicular to the XY plane (that is, the gravity direction) is expressed as the Z direction. To do. In the Z direction, the direction against gravity is expressed as up and the direction in which gravity works is expressed as down. Further, the direction of rotation about the Z direction as the central axis is the θ direction.

FIG. 1 is a perspective view showing an example of a form embodying the present invention. FIG. 1 is a perspective view showing the outer appearance of a holding table 1 according to the present invention.

The holding table 1 holds a stretchable expanded sheet Ws (referred to simply as a work W) attached to an annular wafer ring Wr for holding the dicing chip component D in a predetermined posture. .. Specifically, the holding table 1 includes an outer peripheral support part 2, an inner peripheral support part 3, a negative pressure suction part 4, and the like.

The expanded sheet Ws has adhesiveness on the first surface (for example, upper surface) S1 side that holds the chip component D, and has non-adhesiveness on the second surface (for example, lower surface) S2 side that is in front and back relation with the first surface S1. Have a composition. Then, the diced chip component D is attached (that is, held) to the adhesive first surface S1 side. Further, the expanded sheet Ws is made of a resin film containing a material having excellent flexibility such as polyvinyl chloride (PVC), polyethylene terephthalate (PET), and polyolefin (PO) and has elasticity.

The wafer ring Wr fixes the outer periphery of the expanded sheet Ws. Specifically, the wafer ring Wr has an annular shape with a hollow outer peripheral edge Wx and an inner peripheral edge Wn with a hollowed inside, and is made of a thin plate of aluminum, stainless steel, resin, or the like. More specifically, the expanded sheet Ws is attached to the lower surface side of the wafer ring Wr, and the outer peripheral edge Wt of the expanded sheet Ws is arranged at the same as or inside the outer peripheral edge Wx of the wafer ring Wr. ing.

The outer peripheral support portion 2 abuts and supports the outer peripheral portion of the expanded sheet Ws outside the chip holding region Rd in which the chip component D is held, from the second surface S2 side having non-adhesiveness to support the work W. It is supported in a predetermined posture.
Specifically, the outer peripheral support portion 2 includes a contact surface 21, a hole groove portion 41 whose details will be described later, and a protruding portion 5.

The contact surface 21 is a portion that supports the outer peripheral portion of the expanded sheet Ws by contacting it from the second surface S2 side. Specifically, the contact surface 21 has a smooth upper surface, and is affixed to the outside of a portion (indicated by a broken line Cn) where the inner peripheral edge Wn of the annular wafer ring Wr is arranged. Negative pressure is applied to the annular region Rw inside the portion (indicated by the broken line Ct) where the outer peripheral edge Wt of the expanded sheet Ws is arranged to hold the expanded sheet Ws in close contact.

The smoothness required of the contact surface 21 means not only the polished state (smooth surface in a narrow sense) but also a predetermined negative pressure acting on the annular region Rw to hold the expanded sheet Ws in close contact. Including a state that has been molded and cut to the extent possible (smooth surface in a broad sense).

The inner peripheral support portion 3 supports the inner peripheral portion of the expanded sheet Ws including the chip holding region R in which the chip component D is held from the second surface S2 side having non-adhesiveness to support it in a flat posture. Is.

Specifically, in the inner peripheral support portion 3, a portion (that is, the contact surface 31) that contacts the chip holding region R of the expanded sheet Ws is configured by a rough surface (also referred to as a non-smooth surface). The tops of the peaks of the surface are generally flat in the XY directions.

More specifically, the rough surface is formed by subjecting the surface of a smooth plate-shaped member to physical treatment such as sandblasting, cutting, or hot pressing, or chemical treatment such as etching to obtain the outer shape of the diced chip component D. It is processed with concavo-convex at a repeating pitch that is finer than the dimensions. Therefore, in the inner peripheral support portion 3, the contact surface 31 of the expanded sheet Ws with the chip holding region R has a substantially flat top portion of each peak of the rough surface, and each chip component D is It has a shape that can be supported horizontally.

The negative pressure suction part 4 makes the part where the surface (that is, the lower surface) S2 of the expanded sheet Ws on the non-adhesive layer side and the outer peripheral support part 2 come into negative pressure (also referred to as reduced pressure, lower than atmospheric pressure). Is.

Specifically, the negative pressure suction part 4 is configured to include a hole groove part 41, a negative pressure generating means 42, a switching valve 44, and the like.

The hole groove portion 41 applies a negative pressure to a predetermined region of the contact surface 21 with which the expanded sheet Ws contacts. Specifically, the hole groove portion 41 is composed of holes or arc-shaped grooves scattered on the contact surface 21, and is connected to negative pressure generating means or the like. Then, the hole groove portion 41 can exert a negative pressure on the annular region Rw of the contact surface 21 by making the inside of the hole and the groove have a negative pressure with the expanded sheet Ws covering the upper portions of the holes and the groove.

The negative pressure generating means 42 makes the hole groove portion 41 a negative pressure. Specifically, the negative pressure generating means 42 can be, for example, a vacuum pump or an ejector installed outside the holding table 1, or a container (so-called vacuum tank) having a negative pressure inside. More specifically, the negative pressure generating means 42 is connected to the connection port 43 communicating with the hole groove portion 41 via a pressure regulator (so-called vacuum regulator) or a switching valve 44 (not shown).

The connection port 43 can be brought into a negative pressure state in the hole groove portion 41 by a switching operation of the switching valve 44, or can be brought into a state called vacuum break or atmospheric release.

Examples of the switching valve 44 include a manual valve and a solenoid valve.

The projecting portion 5 applies tension to the expanded seat Ws when the expanded seat Ws is supported by the inner peripheral support portion 3. The protruding portion 5 is arranged inside the region of the outer peripheral support portion 2 where the wafer ring Wr is arranged and at a position protruding above the inner peripheral support portion 3.

Specifically, when the holding table 1 is viewed in a plan view (that is, looking down from above), the projecting portion 5 is located inside the region where the inner peripheral edge Wn of the wafer ring Wr is arranged in the outer peripheral support portion 2 and , Is arranged outside the chip holding region Rd in which the chip component D of the expand sheet Ws is held, and when viewed from the side (or also referred to as a cross-sectional view), the contact of the inner peripheral support portion 3 is prevented. It is arranged so as to protrude from the contact surface 31 (specifically, the top portion of each peak of the rough surface).

More specifically, the protrusion 5 is formed of a concentric circular step d. Then, the corners of the step d are circumferentially arranged continuously by 360 degrees. In other words, in the holding table 1, the inner peripheral support portion 3 is recessed from the outer peripheral support portion 2 by a concentric circular step d, and the corner portion of the step d of the outer peripheral support portion 2 projects. It constitutes part 5.

FIG. 2 is a cross-sectional view showing a main part of an example of a form embodying the present invention. 2A to 2D, the manner in which the work W is placed and held on the holding table 1 according to the present invention is illustrated in time series.

First, FIG. 2A shows a state immediately before placing the work W on the holding table 1. The work W is handled by an operator, a transfer robot, or the like, and is carried to a position facing the holding table 1 as shown in the figure. Then, the work W is directly placed on the holding table 1, or the work W is temporarily placed on a rod-shaped support member that moves up and down by an elevator device (not shown) called a lift pin, and then the lift pin is lowered to hold the work W. Place it on 1.

FIG. 2B shows a state immediately after the work W is placed on the holding table 1. At this time, the outer peripheral portion of the lower surface S2 of the expanded sheet Ws is in contact with the contact surface 21 of the outer peripheral support portion 2. On the other hand, the lower surface S2 of the chip holding region Rd of the expanded sheet Ws is not in contact with the inner peripheral support portion 3 or is in a state where a part near the central portion is in contact with the inner peripheral support portion 3.

Therefore, when the protruding portion 5 supports the expanded seat Ws by the outer peripheral support portion 2, the second surface S2 of the expanded seat Ws does not entirely contact the inner peripheral support portion 3, but the step difference of the protruding portion 5 is formed. At d, the expanded seat Ws can be slightly moved away from the inner peripheral support portion 3 so that the air reservoir P can be formed.

FIG. 2C shows a state in which the negative pressure suction portion 4 is in a negative pressure state and the lower surface S2 of the expanded seat Ws is in contact with the inner peripheral support portion 3.

Thereafter, the negative pressure suction portion 4 is placed in a negative pressure state, and the space surrounded by the lower surface S2 of the expanded sheet Ws, the protruding portion 5 and the wall surface of the outer peripheral support portion 2, and the surface of the inner peripheral support portion 3 is depressurized (larger). Lower than atmospheric pressure). At this time, in the expanded sheet Ws, the center portion of the chip holding region Rd hangs downward due to the difference between the atmospheric pressure applied to the upper surface S1 and the pressure applied to the lower surface S2 and the elastic deformation (expansion) of the expanded sheet Ws. As a result, the area of contact with the surface of the inner peripheral support portion 3 gradually increases from the vicinity of the central portion. Then, an air reservoir P is formed near the protruding portion 5, but as the pressure reduction proceeds, the contact area of the expanded sheet Ws expands to the outer peripheral portion.

That is, as the expanded sheet Ws is sucked under negative pressure, the tip holding area Rd far from the protruding portion 5 is closely contacted while following the surface of the inner peripheral support portion 3, and the contacted portion is gradually moved from the central portion to the outer peripheral side. And the volume of the air reservoir P gradually decreases. At this time, the expanded sheet Ws closely adheres to the surface of the inner peripheral support portion 3 while being applied with tension, so that slack and wrinkles can be prevented. Further, it is possible to efficiently suck and exhaust air while preventing the occurrence of air trapping.

FIG. 2D shows a state in which the negative pressure suction section 4 continues to reduce the pressure and the lower surface S2 of the expanded sheet Ws has come into contact with the inner peripheral support section 3.

At this time, the space surrounded by the lower surface S2 of the expandable sheet Ws, the projecting portion 5 and the wall surface of the outer peripheral support portion 2, and the surface of the inner peripheral support portion 3 becomes closer to a vacuum state, and the expandable sheet Ws has elasticity. Together with this, the expanded sheet Ws follows the surface of the inner peripheral support portion 3. Then, the air pool P in the vicinity of the protruding portion 5 becomes small, and the lower surface S2 of the expanded sheet Ws adheres to the surface of the inner peripheral support portion 3 not only in the entire chip holding region Rd but also in the vicinity of the side surface of the protruding portion 5. It becomes a state. At this time, the expanded sheet Ws is in a stretched state by being brought into close contact with the surface of the inner peripheral support portion 3 and the step portion of the protruding portion 5, and tension is generated.

After that, the work W is subjected to predetermined processing while being held in the holding table 1. Then, when the predetermined process ends, the negative pressure suction from the negative pressure suction unit 4 is released.

Then, the air reservoir P near the protruding portion 5 returns from the negative pressure to the atmospheric pressure, and the lower surface S2 of the expanded sheet Ws is separated from the inner peripheral support portion 3 due to the tension acting on the expanded sheet Ws. This peeling gradually spreads from the outer peripheral side (that is, in the vicinity of the protruding portion 5) to the center Rc side of the chip holding region Rd. At this time, due to the presence of the protruding portion 5, the tension acting when the expanded seat Ws is in close contact with the inner peripheral support portion 3 tends to return the expanded seat Ws from the stretched state to the original state. Since it acts as a restoring force, peeling proceeds rapidly.

Since the holding table 1 according to the present invention has the above-mentioned configuration, it does not generate air bites or wrinkles in the chip holding region Rd where the diced chip component D is held, and the time until the suction is completed. Can be shortened. Furthermore, a holding table having a relatively simple structure can be realized. Further, even when the adsorption is released, the restoring force of the expanded sheet Ws works due to the presence of the protruding portion 5, so that the peeling progresses promptly and the time until the adsorption release is completed can be shortened.

[Inner circumference support part 3]
In the above description, the example in which the portion (also referred to as the contact surface) 31 that contacts the chip holding region R of the expanded sheet Ws in the inner peripheral support portion 3 is a rough surface has been shown. By doing so, when adsorbing or releasing adsorption, the state becomes close to point contact instead of surface contact, so expansion and contraction of the expanded sheet Ws is not hindered, and wrinkles and slack can be prevented from occurring. Further, since the abutting surface 31 is configured as a rough surface, air stagnation at the time of closely contacting with the expanded sheet Ws is reduced, air trapping and the like are prevented, and air can be removed more efficiently than a smooth surface. Therefore, the time until completion of suction can be shortened, which is preferable. .. Further, when the negative pressure suction is released, the air for vacuum breakage easily wraps around, so that it is possible to shorten the time until the expandable sheet Ws can be peeled from the inner peripheral support portion 3.

However, the contact surface 31 is not limited to a rough surface, and may have a configuration in which grooves smaller than the outer dimensions of the chip component D are radially or randomly carved. By doing so, each of a large number of chip components D can be supported in a substantially horizontal state in the same plane.

On the other hand, when the expanded sheet Ws is easily peeled off from the inner peripheral support portion 3, the contact surface 31 may be a smooth surface.

[About protrusion 5]
In embodying the present invention, the projecting portion 5 is not limited to the above-described configuration described with reference to FIGS. 1 and 2, and various configurations and configurations may be adopted. Below, the modification of the protrusion part 5 is shown.

FIG. 3 is a perspective view showing a modified example of a mode embodying the present invention. 3A to 3D show perspective views of the appearances of the holding tables 1A to 1D according to the present invention, each of which has a configuration including protrusions 5A to 5D having different shapes and arrangements. ing.

For example, as illustrated in FIG. 3A, the holding table 1A has a configuration including a plurality of protruding portions 5A arranged at the same interval with respect to the center of the inner peripheral support portion 3.
The projecting portion 5A has three cylindrical members, and is inside the region in which the wafer ring Wr is arranged in the outer peripheral support portion 2 and outside the chip holding region Rd in the inner peripheral support portion 3, and the chip holding region Rd. Are arranged at the same distance from the center Rc of the same and at equal intervals (also referred to as uniform angles). The protruding portion 5A is arranged at a position protruding above the inner peripheral support portion 3.

It should be noted that the number of cylindrical members forming the protruding portion 5A may be two, or four or more. For example, six cylindrical members may be arranged, including three at positions shown by broken lines in FIG. The shape of the protruding portion 5A is not limited to the cylindrical shape, but may be a hemispherical shape, a prismatic shape, a fan shape, or the like.

In the holding table 1A, the contact surface 21 of the outer peripheral support portion 2 and the contact surface 31 of the inner peripheral support portion 3 may have the same height (that is, the same plane) or may have a step. May be (not necessarily on the same plane).

On the other hand, as illustrated in FIG. 3B, the holding table 1B includes a plurality of arcuate island-shaped protrusions 5B that are spaced apart from each other at a predetermined interval, and the predetermined interval is equal to that of the inner peripheral support portion 3. It is configured to extend radially toward the center Rc side.
The protruding portion 5</b>B is located inside the outer peripheral support portion 2 where the wafer ring Wr is arranged, outside the chip holding region Rd of the inner peripheral support portion 3, and above the inner peripheral support portion 3. It is located in.

It should be noted that the arcuate island-shaped protrusions 5B may have the same shape and may be arranged in plural at the same interval 5g, or may have different shapes arranged at an unequal pitch.

In the holding table 1B, the contact surface 21 of the outer peripheral support portion 2 and the contact surface 31 of the inner peripheral support portion 3 may have the same height (that is, the same plane) or may have a step. May be (not necessarily on the same plane).

On the other hand, as illustrated in FIG. 3C, the holding table 1C has a configuration in which the protrusions 5C are arranged in a concentric ring island shape with respect to the center Rc of the inner peripheral support portion 3.
The protruding portion 5C is located inside the region where the wafer ring Wr is arranged in the outer peripheral supporting portion 2, outside the chip holding region Rd in the inner peripheral supporting portion 3, and above the inner peripheral supporting portion 3. It is located in.

In the holding table 1C, the contact surface 21 of the outer peripheral support portion 2 and the contact surface 31 of the inner peripheral support portion 3 may have the same height (that is, the same plane) or may have a step. May be (not necessarily on the same plane).

On the other hand, as illustrated in FIG. 3D, the holding table 1D has a configuration including a plurality of projecting portions 5D having a discontinuous uneven inner peripheral shape.
The projecting portion 5D is provided inside the region where the wafer ring Wr is arranged in the outer peripheral support portion 2 and outside the chip holding region Rd in the inner peripheral support portion 3 and above the inner peripheral support portion 3. It is composed of a protruding step. The surface of the protrusion 5D is substantially flush with the contact surface 21 of the outer peripheral support 2.

The surface of each of the protrusions 5 and 5A to 5D may be a smooth surface, or may be a rough surface. If the surface is rough, it is preferable because air can quickly move in and out when suctioning with negative pressure, so that the time until completion of adsorption can be shortened. The same applies when the suction is released.

Alternatively, the surface of each of the protrusions 5 and 5A to 5D may have a groove 5g radially extending toward the center Rc side of the inner peripheral support 3.
Specifically, the groove 5g such as the protrusion 5C illustrated in FIG. 3C may be provided to the protrusion 5B illustrated in FIG. 3B. Alternatively, the groove 5g such as the protrusion 5D illustrated in FIG. 3D may be provided to the protrusion 5 illustrated in FIG.

In this way, the groove portion 5g provided on the surface of the protruding portion is configured to extend radially toward the center Rc side of the inner peripheral support portion 3, so that air can quickly move in and out when negative pressure is sucked. This is preferable because it can shorten the time until the adsorption is completed. The same applies when the suction is released.

With such a configuration, the holding tables 1A to 1D provided with the protruding portions 5A to 5D support the inner peripheral surface of the expandable seat Ws when the second surface S2 of the expandable seat Ws is supported by the outer peripheral support portion 2. Instead of abutting the portion 3 as a whole, the expanded seat Ws can be slightly moved away from the inner peripheral support portion 3 at the step d of the protruding portion 5 so that the air reservoir P can be formed. Therefore, when the expandable seat Ws is supported by the inner peripheral support portion 3, tension can be applied to the expandable seat Ws.

[About work W]
In the above description, as an example of the work W, the circular wafer ring Wr is illustrated and described in detail. However, the embodiment of the wafer ring Wr is not limited to such a configuration, and for example, a substantially annular shape having a linear portion (orientation flat) for orientation in a part of the outer circumference, or an annular shape such as a quadrangle or an octagon. It may be configured by a thin plate member.

Further, in the above description, as an example of the work W, the wafer ring Wr is shown as an annular thin plate member, and the expand sheet Ws is attached and fixed to the lower surface of the wafer ring Wr. However, the embodiment of the work W is not limited to such a configuration, and includes, for example, a circular or square double frame (an inner frame called an inner ring and an outer frame called an outer ring), and these members are expanded. The sheet Ws may be sandwiched and fixed.

[About the outer peripheral support 2]
In the above description, the outer peripheral support portion 2 has a configuration in which the expanded sheet Ws is held in close contact with the contact surface 21 by the negative pressure of the negative pressure suction portion 4. However, the holding table 1 according to the present invention is not limited to such a configuration, and may have a configuration for pressing the wafer ring Wr from above (so-called a clamp mechanism). In this case, the expanded sheet Ws is brought into close contact with the abutting surface 21 under atmospheric pressure, and then the air reservoir P is suctioned under negative pressure to bring the expanded sheet Ws into close contact with the inner peripheral support portion 3.

[Retention table]
The holding table according to the present invention can be used not only in the form of being used alone for holding the work W, but also by being incorporated in various devices and forms for carrying, processing, processing, observing, inspecting, etc. the work W.

1 Holding Table 2 Outer Peripheral Support Part 3 Inner Peripheral Support Part 4 Negative Pressure Suction Part 5 Projection Part 5g Groove Part (Gap)
21 Contact Surface 31 Contact Surface 41 Hole Groove 42 Negative Pressure Generation Means 43 Connection Port 44 Switching Valve W Work Wr Wafer Ring Wn Wafer Ring Inner Edge Wx Wafer Ring Outer Edge Ws Expanded Sheet Wt Expanded Sheet Outer Edge S1 Adhesion Layer-side surface S2 Non-adhesive layer-side surface D Chip component d Step Rd Chip holding area Rc Center P Air pool

Claims (6)

A holding table for holding a dicing chip component, an expandable sheet having elasticity attached to an annular wafer ring, in a predetermined posture,
The expand sheet has a first surface having an adhesive property for holding the chip component, and a second surface having a non-adhesive relationship in a front-back relationship with the first surface,
An outer peripheral support portion, which supports an outer peripheral portion outside the chip holding region in which the chip component is held in the expand sheet, in a predetermined posture by abutting from the second surface side,
An inner peripheral support portion that supports the inner peripheral portion of the expandable sheet including the chip holding region from the second surface side in a flat posture,
A negative pressure suction part that applies a negative pressure to a region where the outer peripheral support part and the inner peripheral support part contact the second surface of the expandable sheet,
The holding table, wherein the outer peripheral support portion includes a protrusion that protrudes above the inner peripheral support portion, inside a region where the wafer ring is arranged. The holding table according to claim 1, wherein a plurality of the protrusions are arranged at the same interval with respect to the center of the inner peripheral support portion. The projecting portion includes a plurality of arc island-shaped projecting portions spaced apart from each other by a predetermined distance,
The holding table according to claim 1 or 2, wherein the predetermined interval extends radially toward the center side of the inner peripheral support portion. The holding table according to claim 1, wherein the projecting portion is arranged in a concentric circular island shape with respect to the center of the inner peripheral support portion. The holding table according to any one of claims 1 to 4, wherein the surface of the protruding portion is provided with a groove portion that extends radially toward the center side of the inner peripheral support portion. The inner peripheral support portion has a rough surface at a portion in contact with the second surface of the expanded seat,
The holding table according to any one of claims 1 to 5, wherein the projecting portion projects above a top portion of each peak of the rough surface.

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