JPH0481850B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to an exposure apparatus that exposes fine patterns on semiconductor wafers, bubble memory wafers, etc.
In particular, the present invention relates to a substrate deforming chuck suitable for flattening the surface of a substrate such as a wafer.

[Background of the invention]

As described in Japanese Unexamined Patent Publication No. 106118/1983, the conventional device uses vacuum pressure to bring a piezo element that deforms the wafer into contact with a thin plate for wafer suction, and expands and contracts the piezo element to create a thin plate for wafer suction. It was designed to partially deform the wafer that was attracted to it. However, in this device, in order to flatten the entire surface of the wafer, it is necessary to increase the arrangement density of the piezo elements, resulting in a problem that the structure becomes complicated. Furthermore, since the wafer suction thin plate and the piezo element are vacuum suctioned, and this thin plate must be larger than the wafer, it is structurally difficult to suction the back side of the wafer and load or unload it into the wafer chuck. The problem was that it was difficult to

[Purpose of the invention]

An object of the present invention is to solve the problems of the prior art by vacuum suctioning a substrate onto its surface, and by deforming a flexible chuck plate to deform the substrate. In addition to simplifying the structure, the overall configuration of the board deforming chuck in which the plurality of vertical movement driving elements are arranged is also simplified, and furthermore, the handler that has sucked the back side of the board can enter the periphery of the chuck board. It is an object of the present invention to provide a substrate deformable chuck in which a substrate can be transferred and placed on the surface of a chuck board by a handler.

[Summary of the invention]

In order to achieve the above-mentioned object, the present invention includes: a flexible chuck plate on which a substrate is vacuum-adsorbed; a base disposed at a predetermined interval on the back side of the chuck plate; A plurality of base rings are fastened to the base at predetermined intervals, and are installed between the chuck plate and the base ring so as to correspond to the base rings, and one end is fastened and fixed to the back surface of the chuck plate. and a plurality of connecting rods having constricted portions near the one end so as to be capable of slight rotational deformation, and further connected to the base ring so as to be capable of slight movement in the axial direction; and a constricted portion of each of the connecting rods. A plurality of laminated piezo elements formed by laminating a large number of ring plate-shaped piezo elements, which are attached by penetrating and sandwiching each connecting rod between the collar and each of the base rings via an insulating plate. and controlling and driving the applied voltage applied to each laminated piezo element to expand and contract each laminated piezo element to slightly move the connecting rod in the axial direction with respect to the base ring and slightly rotationally deform the constriction part. This substrate deforming chuck is characterized in that the chuck plate is deformed by deforming the chuck plate, and the vacuum-adsorbed substrate is deformed to follow the deformed chuck plate.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 1 and 2 are block diagrams showing one embodiment of the wafer planarization chuck of the present invention. This wafer chuck is comprised of a wafer chuck plate 2 for vacuum suctioning a wafer 1, a number of vertically moving elements 4 having elastic support portions 3, and a base 5. The wafer suction plate 2 and the vertical movement element 4 are directly connected through the elastic support part 3, and by moving the vertical movement element 4 up and down, the wafer chuck plate 2 can be deformed. The wafer chuck plate 2 is a thin plate made of aluminum, glass, silicon, stainless steel, or phosphor bronze, and has a land portion 6 for sucking the wafer 1 and a vacuum suction port 7 on its surface.

The vertical movement element 4 needs to have a stroke sufficient to flatten the wafer 1. Since the warpage and waviness (thickness unevenness) of the wafer 1 is less than 10 to 20 μm, the stroke of the vertical motion element 4 is 30 μm or less.
~50 μm is sufficient. As the vertically moving element 4, a piezo element that expands and contracts depending on an applied voltage is most suitable for the use of the present invention.

FIG. 3 shows a configuration in which a piezo element is used as the vertical movement element 4 of the present wafer chuck.

The piezo element 10 is made by stacking multiple ring plate-shaped piezo elements, and when DC500V is applied, the stroke is 30 ~
Use one that generates 50 μm. This piezo element 10 is connected via two upper and lower insulating plates 11.
It is attached between the connecting rod 12 and the base ring 13. Note that by fixing the connecting rod 12 and the base ring 13 with a nut 15 via a counter spring 14, the piezo element 10
In addition, it has a structure that prevents damage to the piezo element 10 when force other than in the vertical direction is applied. base ring 13
is fixed to the base 5 with mounting bolts 16.

An elastic support portion 3 having a constriction is provided at the upper end of the connecting rod 12, and the tip thereof is connected to the wafer chuck plate 2 by a screw 17. This elastic support part 3 has a constriction 3 designed to have low rigidity against the inclination of the wafer chuck plate 2 that is deformed by the vertical displacement of each vertical movement element, but on the other hand, to form a connection part with high rigidity in the vertical direction. It is something.

4 and 5 show a method of planarizing a wafer using the wafer planarizing chuck described above.

First, as shown in FIG. 4, a wafer 1 having warps or undulations (uneven thickness) is fixed to a wafer chuck plate 2. As shown in FIG. Although the warpage of the wafer 1 is eliminated by vacuum adsorption to the wafer chuck plate 2, the waviness (thickness unevenness) remains.
The flatness is as shown in Fig. 4. The flatness of the surface of the wafer 1 is measured by a wafer flatness measuring device 20. The wafer flatness measuring device 20 uses a known technique such as a laser interference method or a flatness measuring device using a capacitive sensor.

FIG. 5 shows that the amount of expansion and contraction of each vertically moving element 4 (piezo element) is calculated using a computer based on the wafer flatness measurement results measured in FIG.
By applying a voltage to each vertically moving element 4, the wafer 1
The figure shows a flattened state.

The wafer chuck plate 2 is elastically deformed by the expansion and contraction of the vertical movement element 4, and the wafer 1 is deformed together with the wafer chuck plate 2. At this time, vertical movement element 2
is fixed to the base 5, the inclination between the wafer chuck surface 2 and the vertical movement element 2 is absorbed by the elastic support portion 3.

Next, an embodiment of the method of loading the wafer 1 into the present wafer planarization chuck is shown in FIGS. 6 and 7.

This wafer chuck has a lifter (for example, a small cylinder, a DC solenoid, a linear mechanism using a motor and a screw, a cam mechanism, etc.) 30 in the center.
A vacuum pad 31 is provided at the tip of the wafer 1 to attract the back surface of the wafer 1. Uehachiku board 2
A seal ring 32 is provided between the lifter 30 and the lifter 30.

FIG. 6 shows the state in which the wafer 1 is loaded onto a wafer chuck. First, the wafer handler 33 picks up the left and right rear surfaces of the wafer 1 with the vacuum chuck 34, and moves it onto the wafer chuck. Next, the vacuum pad 3 lifted by the lifter 30
The wafer 1 is transferred to the wafer 1.

FIG. 7 shows a state in which wafer loading has been completed.

When the wafer 1 is attracted to the vacuum pad 31,
The wafer handler 33 releases the vacuum suction of the wafer 1 and retreats from the back side of the wafer 1 to the left and right, and then, as the lifter 30 descends, the wafer 1
The wafer is lowered onto the chuck board 2. Wafer 1 is
The wafer is vacuum-adsorbed onto the chuck plate 2, and loading is completed. Note that the wafer can be unloaded by following the above sequence in reverse.

In this manner, the present wafer planarization chuck can load and unload the wafer 1 without contacting the surface of the wafer 1.

8 and 9 illustrate another method of loading a wafer 1 into a wafer planarization chuck.

Cutouts 35 are provided at both ends of the wafer chuck plate 2 so that the wafer handler 33 can be lowered.

First, the wafer 1 is set from above on the wafer chuck plate 2 with the back surfaces of both left and right ends supported by the vacuum chucks 34 of the wafer handler 33.

Next, wafer loading is completed by vacuum suctioning the wafer 1 to the wafer chuck plate 2 and simultaneously releasing the vacuum suction of the wafer handler 33. Unlike the methods shown in FIGS. 6 and 7, this method does not require a mechanism such as the lifter 30 in the wafer chuck, but on the other hand, the operation of the wafer handler 33 becomes complicated.

〔Effect of the invention〕

According to the present invention, each vertical movement driving element, which is a piezo element that vacuum-chucks a substrate onto the surface and deforms a flexible chuck plate to deform the substrate, is directly connected and supported to the chuck plate. This structure simplifies the structure of each vertically movable drive element made of the piezo element, and also simplifies the overall structure of the substrate deformable chuck in which the plurality of vertically movable drive elements are arranged, and furthermore, the peripheral part of the chuck plate is simplified. Another advantage is that the handler that has sucked the back side of the substrate can enter the handler, and the handler can transport and place the substrate on the front surface of the chuck board. Furthermore, when the present invention is applied to a proximity exposure apparatus such as an X-ray exposure apparatus, fine circuit patterns can be exposed with high resolution.

[Brief explanation of the drawing]

FIG. 1 is a plan view of the wafer flattening chuck, FIG. 2 is a central sectional view of FIG. 1, FIG. 3 is a detailed sectional view of the vertical movement element of FIG. 1, and FIGS. An explanatory diagram showing a wafer flattening method, FIGS. 6 and 7 are cross-sectional views showing an example of a wafer loading method,
FIG. 8 is a plan view showing another embodiment of the wafer loading method, and FIG. 9 is a sectional view at the center of FIG. 1... Wafer, 2... Wafer chuck board, 3...
. . . elastic support portion, 4 . . . vertical movement element, 5 . . . base, 10 . . . piezo element, 20 .

Claims (1)

[Scope of Claims] 1. A flexible chuck plate on which a substrate is vacuum-adsorbed, a base disposed at a predetermined interval on the back side of the chuck plate, and a predetermined interval at the base. A plurality of base rings are arranged between the chuck plate and the base ring to correspond to the base rings, and one end is fastened and fixed to the back surface of the chuck plate, and a plurality of base rings are fastened to the base ring, and a plurality of connecting rods having constricted portions so as to be capable of slight rotational deformation and further connected to the base ring so as to be capable of slight movement in the axial direction; a flange of the constricted portion of each of the connecting rods; and each of the bases; A plurality of laminated piezo elements formed by laminating a large number of ring plate-shaped piezo elements, each connecting rod being inserted and sandwiched between the piezo ring and the ring through an insulating plate. The applied voltage applied to each laminated piezo element is controlled and driven to expand and contract each laminated piezo element, thereby slightly moving the connecting rod in the axial direction with respect to the base ring, and slightly rotationally deforming the constricted portion to remove the chuck plate. 1. A substrate deforming chuck characterized in that it is configured to deform a chuck plate and deform a vacuum-adsorbed substrate to follow the deformed chuck plate. 2. A lift mechanism is provided at the center of the chuck plate and moves up and down through the chuck plate from below the chuck plate, and the lift mechanism attracts the back side of the substrate to the upper end of the lift mechanism to lift the substrate against the surface of the chuck plate. 2. The substrate deformable chuck according to claim 1, characterized in that the chuck is configured to be able to be raised and lowered.