JPH0513315A - Wafer holder - Google Patents

Abstract

PURPOSE:To provide a wafer holding device into which a wafer, a simple substance, is inserted singly to be secured acurately. CONSTITUTION:This wafer holding device is so structured that a wafer 4 is held on a wafer holder 3 by electrostatic attraction and the wafer holder 3 holding the wafer 4 is guided up and down and is pressed by a top reference plane 1a to be sucured at a location where an exposed surface 4a of the wafer is not brought into contact with the top reference plane 1a. It is desired that the wafer holder 3 is guided by an independent spring from the transverse direction and is secured. By this method, the flatness of the exposed surface 4a is finely maintained and exposure can be performed as far as an edge.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wafer holding device for fixing and holding a wafer, and is most suitable for use in, for example, a charged particle beam exposure apparatus used for manufacturing a semiconductor integrated circuit.

[0002]

2. Description of the Related Art Conventionally, one of the devices of this type is a pallet system in which a pallet for holding and holding a wafer is provided, the wafer is fixed to the pallet, and then the pallet is placed and fixed on a stage.

Furthermore, an electrostatic chuck for electrostatically attracting a wafer by electrostatic force is provided, and a wafer holder equipped with this electrostatic chuck is urged by a spring to press and fix the wafer against an upper surface reference member. There were also schemes.

[0004]

However, in the case of the pallet type, since the wafer is fixed on the pallet and then placed on the stage, the object to be transferred is large and heavy, and therefore the transfer system is large. Further, there is a problem that manpower is required to fix the wafer to the pallet.

Further, in the electrostatic chuck type, the wafer is pressed against the upper surface reference member by a spring and fixed by only frictional force. However, since the electrostatic chuck is a heavy object, the pressing force is necessarily large in order to fix the wafer holder. Therefore, there is a problem in that the wafer may be pressed against the upper surface reference member with a large force and the wafer may be damaged.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a wafer hold device for easily and surely fixing a wafer.

[0007]

A wafer hold device according to the present invention as defined in claim 1 comprises a device main body having a vertical reference surface and a flat surface for electrostatically supporting a wafer. A support member is vertically movably guided by the apparatus main body and is positioned upward by the reference surface at a position where the upper surface of the supporting wafer is not in contact with the reference surface, and a driving unit for vertically driving the support member.

In the wafer holding device of the present invention as defined in claim (2), as a desirable pressure fixing, a guide member for guiding the supporting member so as to be vertically movable is formed on the supporting member.
-F surface, and a contact member of the apparatus body that contacts the VF surface,
A first pressing member of the apparatus main body that presses the VF surface against the contact member, and after the wafer contacts the reference surface, V with a stronger pressing force than the first pressing member together with the first pressing member. A second pressing member that presses the -F surface against the contact member is provided in the apparatus main body.

[0009]

The wafer is held by the wafer holder by electrostatic attraction, and the wafer holder holds the wafer and guides it in the vertical direction. At the position where the exposed surface of the wafer does not contact the upper reference surface, the wafer holder is pressed against the upper reference surface. Preferably, the wafer holder is laterally guided by individual springs and fixed.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. FIG. 1 and FIG. 2 are a B arrow view (partial cross section) and an AA arrow view of an embodiment in which a wafer is held, respectively. Wafer 4 has a diameter of 150 mm and a thickness of 0.62
It is a 5 mm disk-shaped silicon wafer.

The upper surface has a reference surface 1a having a high degree of flatness as a lower surface, and the positioning column 1 of the wafer holder 3 is formed on the lower surface.
The upper surface reference member 1 with which 2a, 12b, 12c abut has a substantially rectangular plate shape, and has a shape in which a hole 1d having a diameter of 160 mm, which is slightly larger than the diameter of the wafer 4, penetrates through the central portion. The diameter of the hole 1d is larger than the diameter of the wafer 4
The entire surface can be exposed. Two stoppers 5a, 5 having spherical portions 5a ', 5b' at the tip from the upper reference surface 1a
b is formed so as to project downward. The spherical portion 5a 'of one stopper 5a is a V-shaped reference surface 6 formed on the wafer holder 3.
And the spherical portion 5 of the other stopper 5b.
b ′ is in contact with the plane reference surface 7 at one point.

The upper surface 3a of the wafer holder 3 forms a highly accurate flat surface, and the wafer 4 can be held by suction by the electrostatic chuck function provided.

The wafer holder 3 has positioning columns 12a, 1
The tips of 2b and 12c are the top reference plane 1 of the top reference member 1.
It is formed in three places so as to contact a. The amount of protrusion of the positioning columns 12a, 12b, 12c depends on the wafer holder 3
It is higher than the upper surface of the wafer 4 adsorbed on.
Further, a V-shaped reference surface 6 that abuts on the spherical portion 5a 'of one stopper 5a and a flat reference surface 7 that abuts on the spherical portion 5b' of the other stopper 5b are formed so as to be oriented in the lateral horizontal direction. A drive member 3d that receives a vertical force from a drive device (not shown) is fixed to the lower surface of the central portion of the wafer holder 3.

The moving stage 2 is in the shape of a thick square plate, and has a shallow wide recess for accommodating the wafer holder 3 in the central portion thereof, and its peripheral edge is a bank. The peripheral bank is the upper surface 2
a is formed so as to be in contact with the peripheral edge of the upper surface reference surface 1a of the upper surface reference member 1, and the movable stage 2 is fixed to the upper surface reference member 1 by screws 1A to 1D in a state where both surfaces are in contact with each other. .

The wafer 4 is provided on a part of the bank of the moving stage 2.
Is provided with a notch 2e serving as a doorway. Wafer 4
Is inserted from the F direction through the notch 2e into the space between the upper surface reference member 1 and the moving stage 2 by an arm or the like, and is taken out in the direction opposite to the F direction.

A leaf spring 8 and a leaf spring 9 are fixedly mounted on the inner wall surface 2d of the bank. The contact portion 9'of the leaf spring 9 contacts the side surface of the wafer holder 3 so that the V-shaped reference surface 6 and the flat reference surface 7 of the wafer holder 3 are always in contact with the spherical portion 5a 'and the spherical portion 5b', respectively. The leaf spring 8 has a stronger urging force than the leaf spring 9, and prevents the piezoelectric element 10 from extending and the abutting portion 8 ′ of the leaf spring 8 abutting on the side surface of the wafer holder 3 during the vertical movement of the wafer holder 3. When the wafer holder 3 rises and the positioning columns 12a, 12b, 12c come into contact with the upper surface reference member 1, the piezoelectric element 10 contracts so that the contact portion 8'of the leaf spring 8 pushes the side surface of the wafer holder 3 with a strong force. Is configured.

A flat cable (not shown) is connected to the piezoelectric element 10. When electricity is conducted, the piezoelectric element 10 operates and becomes longer (extended) to separate the leaf spring 8 from the wafer holder 3. When electricity is cut off and becomes inoperative, the piezoelectric element 10 becomes shorter and leaves the leaf spring 8. The wafer holder 3 is pressed.

A recess formed on the moving stage 2 (not shown)
A hole 2g penetrates through the center of the drive member 3d and the drive member 3
A power member (not shown) that is supplied to d to move the moving stage 2 up and down is inserted.

The coil springs 11a, 11b, 11c are arranged between the bottom surface 2c of the hole 2b formed in the moving stage 2 (only the one corresponding to the coil spring 11b is shown) and the lower surface 3b of the wafer holder 3 therebetween. The wafer holder 3 is biased upward (toward the upper surface reference member 1).

The wafer 4 is the upper surface 3 of the wafer holder 3.
It is electrostatically attracted to a and is held horizontally. The structure for electrostatically attracting this wafer is well known such as an electrostatic chuck.

Next, the operation will be described. When the wafer 4 is inserted into the wafer holder 3, the piezoelectric element 10 is first energized. The piezoelectric element 10 expands to separate the leaf spring 8 from the wafer holder 3, and releases the state in which the V-shaped reference surface 6 and the flat reference surface 7 of the wafer holder 3 are pressed by the spherical portions 5a ', 5b' with a strong force. In this state, a power member (not shown) is engaged with the notch of the driving member 3d to lower the wafer holder 3 against the pressing force of the coil spring 11.

Thereafter, the wafer 4 is passed through the notch 2e and inserted into a predetermined position on the wafer holder 3 with an arm (not shown).

Then, the power member (not shown) rises, and the wafer holder 3 is pushed up by the strong bias of the coil spring 11 until the tips of the positioning columns 12a, 12b, 12c come into contact with the upper reference surface 1a of the upper reference member 1. While being strongly pressed, the wafer 4 is electrostatically attracted to the upper surface 3a.

After that, the energization of the piezoelectric element 10 is stopped. Since the piezoelectric element 10 is shortened and does not hinder the pressing of the leaf spring 8 toward the wafer holder 3, the leaf spring 8 urges the wafer holder 3 to the spherical portions 5a 'and 5b' by the urging thereof to tighten the wafer holder 3.

The wafer 4 is adsorbed and fixed to the upper surface 3a of the wafer holder 3, and at that time, the upper surface 3a remains below the upper surface reference surface 1a of the upper surface reference member 1, but the entire surface can be exposed through the hole 1d.

When the wafer 4 is removed from the wafer holder 3, the piezoelectric element 10 is first energized. The piezoelectric element 10 expands to separate the leaf spring 8 from the wafer holder 3 and release the tension. In this state, the power member (not shown) pulls the driving member 3d downward, compresses the coil spring 11, and
Is lowered to a predetermined position (position for inserting / removing the wafer 4). Then, an arm (not shown) is inserted from the F direction to a predetermined position on the wafer holder 3 through the notch 2e. The attraction of the electrostatic chuck is released, and the wafer 4 is placed on the arm (not shown) and taken out from the notch 2e.

Subsequently, another wafer 4 can be passed through the notch 2e and inserted into a predetermined position on the wafer holder 3 with an arm (not shown) to transfer the wafer 4 onto the wafer holder 3.

The apparatus to be held in this embodiment is a silicon wafer having a diameter of 150 mm and a thickness of 0.625 mm, but it goes without saying that the shape and material are not limited to this.

[0029]

Since the wafer is inserted as a single unit and the wafer is suction-held on the wafer holder, the flatness of the exposure surface is kept good and the edge can be exposed. The posture of the wafer holder is stably guided in the vertical direction, and the wafer is transferred with good accuracy.

[Brief description of drawings]

FIG. 1 is a view (partial cross section) taken along arrow B in a state of holding a wafer according to an embodiment.

FIG. 2 A- in a state of holding a wafer of one embodiment
FIG.

[Explanation of symbols]

1. ． Top reference member, 1a. ． Top reference surface, 2. ． Moving stage, 3. ． Wafer holder, 4. ． Wafer, 4
a. ． Exposed surface, 5a, 5b. ． Stopper, 5a ', 5
b '. ． Spherical portion, 6. ． V-type reference surface, 7. ． Plane reference plane, 8. ． Leaf spring, 9. ． Leaf spring, 10. ． Piezoelectric element,
11a, 11b, 11c. ． Coil springs, 12a, 12
b, 12c. ． Positioning pillar

Claims (2)

[Claims] 1. A device main body having a vertical reference surface,
A support member that has a flat surface for electrostatically supporting the wafer and is vertically movably guided by the apparatus main body and is positioned upward by the reference surface at a position where the upper surface of the supporting wafer does not contact the reference surface. And a drive means for vertically driving the support member. 2. A guide member for guiding the support member so as to be vertically movable, and a V-F surface formed on the support member, and the V-face.
-The abutting member of the apparatus body that abuts the F surface, and the V-
A first pressing member of the apparatus body that presses the F surface against the contact member, and after the wafer contacts the reference surface,
2. The apparatus main body is provided with a second pressing member that presses the VF surface against the abutting member with a pressing force stronger than that of the first pressing member, together with the first pressing member. The wafer hold device described in 1.