JPH09281717A - Mechanism for positioning mask stage - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to improve the positioning accuracy at the time of opening and closing a mask stage and to exactly position a mask stage to a base plate with good reproducibility. SOLUTION: The mask stage MS is composed of a mask holding frame MS1 for holding a mask and a mask opening/closing frame MS2. This mask opening/closing frame MS2 is openably and closably mounted at the base plate BP. The mask holding frame MS1 and the mask opening/closing frame MS2 are provided with first three point contraposition base elements consisting of three pieces of auxiliary ball end screws Bs2 and auxiliary V-groove bodies V2. The mask holding frame MS1 and the base plate BP are provided with second three point contraposition base elements consisting of three pieces of auxiliary ball end screws Bs1 and auxiliary V-groove bodies V1. The mask holding frame MS1 is positioned with respect to the mask opening/closing frame MS2 by the first three point contraposition base elements when the mask opening/closing frame MS2 is open. The mask holding frame MS1 is positioned with respect to the base plate BP by the second three point contraposition base elements when the mask opening/closing frame MS2 is closed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
An exposure device is used to produce a CD substrate. In these exposure apparatuses, it is required to accurately expose the mask pattern onto a predetermined position of a work such as a semiconductor wafer or an epoxy resin. The present invention relates to a mask stage positioning mechanism used in the above-described exposure apparatus and the like. In particular, the present invention relates to a mask stage positioning mechanism that can reproducibly position a mask stage at an original position when the mask stage is opened and closed. The present invention relates to a positioning mechanism.

[0002]

2. Description of the Related Art As one of exposure apparatuses for manufacturing semiconductor devices and the like, a proximity exposure apparatus is known in which a mask and a work are brought close to each other to expose a mask pattern on the work. In the exposure apparatus such as the proximity exposure apparatus described above, the mask and the work are aligned so that the mask and the alignment mark printed on the work are overlapped. The alignment is usually performed by providing an alignment mark on the exposed surface side of the workpiece and aligning the alignment mark with the alignment mark provided on the mask.
The work is performed by moving the work stage on which the work is placed so that the marks are overlapped (hereinafter, this method is referred to as surface alignment).

FIG. 11 is a diagram showing a configuration of a proximity exposure apparatus for aligning a mask and a work by the above-mentioned surface alignment. In the figure, MS is a mask stage to which the mask M is attached by means such as vacuum suction. The mask stage MS is attached with an axis Sh whose both ends are rotatably attached to the base BP, and the mask stage MS rotates about the axis Sh. Therefore, the mask stage MS can be opened and closed by holding the handle Ha and moving it up and down.
A vacuum suction pad Vp1 is provided on the base BP, and when the mask stage MS is closed, a vacuum is supplied to the vacuum suction pad Vp1 to fix the mask stage MS by vacuum suction.

FIG. 12 is a view showing a sectional structure of the vacuum suction pad. A flat bush Bu2 is attached to the mask stage MS, and a bush Bu1 having a spherical tip is attached to the vacuum suction pad Vp1. And
The bush Bu1 is provided with a pipe line, and a vacuum is supplied between the internal space of the suction pad Vp1 and the mask stage MS via this pipe line, and the flat bush Bu of the mask stage MS is supplied.
2 is adsorbed on the adsorption pad Vp1 to fix the mask stage MS.

Returning to FIG. 11, WS is a work stage, and the work W is placed on the work stage WS and fixed by means such as vacuum suction. The work stage WS is attached to the XYθ stage XYS via the gap setting mechanism GU, and the XYθ stage XYS is further attached to the Z stage ZS. Then, the XYθ stage XYS moves in the X (horizontal direction in the figure) and Y (vertical direction with respect to the paper surface in the figure) directions by a driving device (not shown), and is centered on an axis orthogonal to the X and Y axes. Rotate (this rotation is hereinafter referred to as moving in the θ direction). Further, the Z stage ZS is moved in the Z direction (vertical direction in the figure) by a driving device (not shown). Therefore, the control device C
The work stage WS can be moved in the X, Y, θ, and Z directions by controlling the drive unit with nt. As the gap setting mechanism GU, the one disclosed in Japanese Patent Application Laid-Open No. 7-74096 previously proposed by the present applicant can be used. The gap setting mechanism GU holds the mask M and the work W at a predetermined gap. It is possible to set them in parallel while doing so (hereinafter, setting in such a state is referred to as "parallelizing").

That is, at least three gap setting mechanisms GU are provided on the XYθ stage XYS, and each gap setting mechanism GU has a first unit U1 fixed to the XYθ stage XYS and the unit U1. The second unit U2 is attached so as to be movable in the Z direction. The work stage WS is placed on the second unit U2. Also, the first unit U1
Is provided with a holding mechanism for holding the relative position of the second unit U2 with respect to the first unit U1 by a holding signal given from the outside. For this reason, the work stage WS is raised in the Z direction by the Z stage ZS, and in the state where the entire surface of the work W is in contact with the mask M, the holding mechanism causes the first unit U1 and the second unit U1 of each gap setting mechanism to move.
By holding the relative position of the unit U2, and then lowering the work W by a predetermined amount in the Z-axis direction while maintaining the posture of the work stage, the mask M and the work W can be parallelized. Yes (Gap setting mechanism GU
For details of the configuration and operation of the above, refer to the above publication).

In order to align the mask M and the work W, the mask M and the work W have a mask alignment mark MAM (hereinafter referred to as a mask mark) and a work alignment mark WAM (hereinafter referred to as a work mark).
Is marked. Alignment mark MAM, W
AM is observed with the surface microscope AU for alignment, and the work stage WS is moved so that the mask mark MAM and the work mark WAM overlap with each other, and the mask M and the work W
Perform position adjustment.

Next, the surface alignment exposure procedure by the apparatus shown in FIG. 11 will be described. (1) Open the mask stage MS, place the work W on the work stage WS, and fix it by means such as vacuum suction. (2) The mask stage MS is closed and the vacuum suction pad Vp1
The mask stage MS is fixed to the base BP by. (3) Press the start switch (not shown). This allows
The control device Cnt parallelizes the mask M and the work W. That is, as described above, the relative position of the first unit U1 and the second unit U2 by the holding mechanism in the state where the work stage WS is raised by the Z stage ZS and the entire surface of the mask M and the work W are brought into contact with each other. To fix. Then, a predetermined amount of work stage W is set so that a predetermined gap is set between the work W and the mask M while maintaining the posture of the work stage WS with respect to the XYθ stage XYS.
Lower S.

(4) The retracted alignment surface microscope AU is set on the mask mark MAM, and the mask mark MAM and the work mark WAM are observed. Then, while watching the monitor (not shown), the XYθ stage XYS is controlled to match the positions of the mask mark MAM and the work mark WAM. (5) The work stage WS is moved in the Z direction by the Z stage ZS, the gap between the mask M and the work W is set to a predetermined exposure gap, the alignment surface microscope AU is retracted, and the exposure (not shown) is performed. The mask M is irradiated with exposure light from the light irradiation device, and a pattern is exposed on the mask M on the work W. (6) The work stage is returned to the origin position, the holding mechanism of the gap setting mechanism GU is released to set the work stage WS in a free state, and further, the vacuum that sucks the work W in vacuum is released. (7) The vacuum supplied to the vacuum suction pad Vp1 is released, the mask stage MS is opened, and the work W is taken out. (8) The work W is exposed by repeating the above operations (1) to (7).

In the case of exposure by the surface alignment described above, the work mark WAM and the mask mark MAM
It is not necessary to open and close the mask stage MS during the alignment because the alignment can be performed by observing simultaneously. Therefore, the positioning accuracy when opening and closing the mask stage is not required. On the other hand, in recent years, there is an increasing demand for back surface alignment for aligning the mask M with the work using a work W having an alignment mark on the back surface side of the exposed surface.

FIG. 13 is a view showing the arrangement of a proximity exposure apparatus for aligning the mask and the work by the above-mentioned back surface alignment. In the figure, the same components as those shown in FIG. 11 are designated by the same reference numerals, and in FIG. 13, an observation hole HW for observing the work mark WAM is provided in the work stage WS. A rear surface microscope AU ′ for alignment is provided so as to face the observation hole HW.

In FIG. 13, the exposure by the back surface alignment is performed as follows. (1) The mask stage MS is closed and the vacuum suction pad Vp1
The mask stage MS is fixed to the base BP by. (2) The position of the back microscope AU ′ for alignment is fixed in advance so that the mask mark MAM can be seen, and the mask mark MAM is displayed on a monitor (not shown). Then, for example, the operator operates a freeze switch or the like to store the position of the mask mark MAM in the control device. (3) The vacuum of the vacuum suction pad Vp1 is released, the mask stage MS is opened, the work W is placed on the work stage WS, and is fixed by means such as vacuum suction. (4) The mask stage MS is closed and the vacuum suction pad Vp1
The mask stage MS is fixed to the base BP by. (5) Press the start switch (not shown). This allows
The controller Cnt parallelizes the mask M and the work W as described above.

(6) The focus of the backside microscope AU 'for alignment is set in a state where the work mark WAM on the back side of the work W can be observed, and the mask mark MAM stored and the position of the work mark WAM currently observed are monitored. The XYθ stage XYS is controlled so as to match on the screen, and the positions of the mask mark MAM and the work mark WAM are matched. (7) The work stage WS is moved in the Z direction by the Z stage ZS to set the gap between the mask M and the work W to a predetermined exposure interval, and the exposure light is irradiated from the exposure light irradiation device (not shown) to the mask M. The work W is exposed by irradiating the mask W with a pattern. (8) The work stage WS is returned to the origin position, the holding mechanism of the gap setting mechanism GU is released to set the work stage WS in a free state, and further, the vacuum that has vacuum-adsorbed the work W is released. (9) The vacuum supplied to the vacuum suction pad Vp1 is released, the mask stage MS is opened, and the work W is taken out. (10) The operations of (1) to (8) are repeated to expose the work W.

In the case of the exposure by the back surface alignment described above, it is necessary to store the position of the mask mark MAM, open the mask stage MS, and set the work W on the work stage WS. For this reason,
When the mask stage MS is closed after the mask stage MS is opened and the work W is set, if the position of the mask stage MS deviates from the previous position, accurate alignment cannot be performed. That is, in the case of back surface alignment, high accuracy is required for the reproducibility of the mask stage position when opening and closing the mask stage MS.

FIG. 14 is a view showing the mounting structure of the rotating part of the mask stage MS of the above-mentioned exposure apparatus. In the figure, MS is a mask stage, Sh is an axis, and the mask stage MS and the axis Sh are fixed by a set screw SB. A support Spt is attached to both ends of the shaft Sh, and a bearing Ba is provided between the housing Hs attached to the base BP and the support Spt.
Then, as shown in the figure, there is a gap G1 between the bearing Ba and the housing Hs due to the fitting of the bearing Ba and the shaft Sh, and between the support Spt and the shaft Sh, there is a gap between the bearing Ba and the housing Hs. There is a gap G2 due to fitting.

As described above, the axis Sh of the mask stage MS is
Since the gaps G1 and G2 are present in the mounting portion, there is backlash and deviation between the mask stage and the base, and the positioning accuracy when opening and closing the mask stage MS is low. Therefore, when the mask stage MS is opened and closed, the position of the mask stage MS shifts by about 10 μm to 50 μm. If the above gaps G1 and G2 are eliminated and a "tight fit" is made, the positioning accuracy is improved, but the maintenance is deteriorated because the positioning accuracy cannot be disassembled. Further, even in the case of “close fit”, when the opening and closing of the mask stage MS is repeated, the bearing is worn due to friction, and backlash occurs in the bearing part in time, and the positioning accuracy at the time of opening and closing is deteriorated. Further, in the case of "close fit", when an external force other than a fixed direction is applied when the mask stage MS is opened and closed, when the mask stage MS is closed, the mask stage MS is fixed in a position displaced from a predetermined position, and the positioning accuracy is improved. Reproducibility is not good. Further, since the vacuum suction pad Vp1 has the structure shown in FIG.
The mask stage MS cannot be restricted to a predetermined position by the vacuum suction pad Vp1.

[0017]

As described above,
In the back surface alignment, it is necessary to accurately position the mask stage MS when opening and closing the mask. However, in the structure of the rotating part of the mask stage, the mask stage M is
When S is opened and closed, it cannot be positioned accurately. Generally, as a structure for accurately positioning a certain member with respect to another member, a method using a ball tip screw and a V groove body is known. FIG. 15 shows the above method using the mask stage M.
It is a figure which shows the structure applied to the positioning of S. In the figure, Bs1 is a ball tip screw attached to the mask stage MS, three ball tip screws Bs1 are provided, and a ball is attached to the tip thereof. Further, the base BP is provided with a V groove body V1 corresponding to the ball tip screw Bs1. Further, the suction pad Vp1 described above is attached to the base BP.

In the above structure, the mask stage MS
Is closed and the mask stage MS is fixed by the vacuum suction pad Vp1, if all the balls at the tip of the ball tip screw Bs1 accurately enter the grooves of all the V groove bodies V, the mask stage MS is Positioning can be performed with good reproducibility. Therefore, in order to improve the positioning accuracy when opening and closing the mask stage MS, as shown in FIG.
Although the above technique was applied to the exposure apparatus having the structure shown in FIG. 14, it was not always possible to improve the positioning accuracy when opening and closing the mask stage MS. This is thought to be due to the following reasons. That is, the mask stage M
The S is attached to the base BP via the axis Sh, and its freedom of movement is limited.

Further, as described above, the mask stage M
There are gaps G1 and G2 at the mounting portion of the shaft Sh of S. Therefore, the mask stage MS has a backlash against the base BP, and when force is applied to the mask stage MS when the mask stage is opened and closed,
Shifts in the direction in which the force is applied. This gap cannot be restored unless a similar force is applied in the opposite direction. For this reason,
When the relative positional relationship between the ball tip screw and the V groove body is deviated due to the above displacement as shown in FIG. 16A, even if the mask stage MS is sucked by the vacuum suction pad Vp1, the ball tip screw Bs1 is not always required. Does not fit in the V groove V. That is, as shown in FIG. 6B, the mask stage MS stops, for example, in one side.
May not be able to be accurately positioned in its original position.

If the amount of backlash or deviation is too large, the ball tip screw B when the mask stage MS is closed.
The probability that s1 and the V groove body V have a predetermined positional relationship is reduced, and as shown in FIG. 16 (c), the tip of the ball tip screw Bs1 may not enter the V groove body. In this state, even if the vacuum suction pad Vp1 sucks the mask stage MS, the tip of the ball tip screw Bs1 cannot be pulled into the V groove body. The present invention has been made to solve the above-mentioned problems of the prior art, and an object of the present invention is to improve the positioning accuracy when opening and closing the mask stage and to reproducibly position the mask stage with respect to the base. It is an object of the present invention to provide a mask stage positioning mechanism that can perform accurate positioning.

[0021]

In order to solve the above problems, the present invention has the following configuration. (1) The mask stage includes a mask holding frame for holding the mask and a mask opening / closing frame, and holds the mask so that the mask holding frame can move with respect to the mask opening / closing frame when the mask opening / closing frame is closed. Attach the frame to the mask open / close frame. Then, the mask opening / closing frame is attached to the base so as to be openable / closable, and when the mask opening / closing frame and the base close the mask opening / closing frame, the mask holding frame and the mask opening / closing frame move in a direction substantially perpendicular to the base surface. Connect as you would. Further, the mask holding frame and the mask opening / closing frame are provided with a first three-point pair element that enables the three-point pair of the two, and the mask holding frame and the base are capable of the three-point pair of both. A second three-point pair base element is set. Then, when the mask opening / closing frame is open, the three-point pair by the second three-point pair base element is released, and the position of the mask holding frame with respect to the mask opening / closing frame is set to the first three-point pair base element. Positioning by
When the mask opening / closing frame is closed, the three-point pair by the first three-point pair base element is released, and the position of the mask holding frame with respect to the base is positioned by the second three-point pair base element. To do.

(2) In (1) above, the above-mentioned first and / or second three-point pair substrate is provided with three protrusions having a curved surface at the tip and three V-grooves having V-grooves. Consists of the body. Then, the V-shaped groove is arranged so that the central axes thereof intersect at a predetermined point. (3) In the above (1), the first and / or second three-point pair substrate is brought into contact with a first protrusion having a curved surface at the tip and the tip of the first protrusion. The pivot bearing, the second protrusion having a curved surface at the tip, the V-groove body in contact with the tip of the second protrusion and having the central axis directed substantially in the direction of the pivot bearing, and the curved surface at the tip. The third projection body has a flat body that is in contact with the third projection body.

According to the first aspect of the present invention, as described in (1) above, when the mask opening / closing frame is open,
The position of the mask holding frame with respect to the mask opening / closing frame is positioned by the first three-point pair element, and when the mask opening / closing frame is closed, the pair of the first three-point pair elements is released to open the mask holding frame. Since the mask holding frame is configured to be movable with respect to the base and the second three-point pair element is used to position the mask holding frame with respect to the base, even if the position of the mask opening / closing frame shifts during opening / closing of the mask, the mask holding frame is It can be accurately positioned with respect to the base.

In the invention of claim 2 of the present invention, since it is configured as in the above (2), even if the mask holding frame, the mask opening / closing frame, and the base are thermally expanded, the central axis of the V groove body is connected. The points where the lines intersect can be held in place. Therefore, if the mask alignment marks are placed at the intersections, the mask alignment marks will not be affected even if thermal expansion occurs.
The position of the mark does not move, and the alignment accuracy can be improved. The invention of claim 3 of the present invention is the above (3).
With this configuration, the mask holding frame and the mask opening / closing frame or the mask holding frame and the base can be positioned with a relatively simple structure.

[0025]

1, 2 and 3 show a first embodiment of the present invention.
A diagram showing a cross-sectional structure of the mask stage and the base of the embodiment of
FIG. 4 is an exploded perspective view of the mask stage and the base shown in FIGS. 1 and 2, and FIG. 5 shows the positional relationship between the tip of the ball tip screw and the V groove body in the state of FIGS. 1, 2, and 3 described above. It is a figure. 1, FIG. 2, and FIG. 3, FIG. 1 shows a state in which the mask is opened, FIG. 2 shows a state in which the mask is closed but has not yet been vacuum-sucked, and FIG. The state where the stage is vacuum-adsorbed and fixed is shown. Note that FIGS. 1, 2, and 3 are A in FIG.
1 shows a sectional structure taken along line A, and in FIGS. 1 to 4, the work stage and the like shown in FIG. 13 are omitted.

First, the structures of the mask stage and the base of this embodiment will be described with reference to FIGS. As shown in FIGS. 1 to 4, the mask stage MS of the present embodiment includes a mask holding frame MS1 for adsorbing and fixing the mask M, and a mask opening / closing frame MS2 rotatably attached to the base BP by an axis Sh.
It is composed of As shown in FIG. 4, three auxiliary ball tip screws Bs2 are attached to the mask holding frame MS1, and the ball at the tip of the auxiliary ball tip screw Bs2 is an auxiliary V attached to the mask opening / closing frame MS2. It engages with the groove formed in the groove body V2. The auxiliary ball tip screw Bs2 is composed of, for example, a male screw having a ball at the tip thereof, and the interval between the mask holding frame MS1 and the mask opening / closing frame MS2 can be adjusted by adjusting the screwing depth. . The screw-in depth of the auxiliary ball tip screw Bs2 is fixed by the nut Nt. Further, the mask holding frame MS1 has three pins Pn.
Is provided in the mask opening / closing frame MS2 through the hole H1.
It is fixed at 1.

The diameter of the hole H1 is larger than the outer diameter of the pin Pn as shown in FIGS. 1 to 3, and the length of the pin Pn is such that the mask holding frame MS1 is in the Z direction with respect to the mask opening / closing frame MS2 (FIG. 4). (Refer to the arrow) It is configured to be movable. Further, a spring Sp is provided on the pin Pn, and the mask holding frame MS1 is biased toward the mask opening / closing frame MS2 by the spring Sp provided on the pin Pn. Further, three ball tip screws Bs1 are attached to the mask holding frame MS1, and the ball at the tip of the ball tip screw Bs1 has a hole H provided in the mask opening / closing frame MS2.
It penetrates 2 and engages with the groove formed in the V groove body V1 attached to the base BP. The ball tip screw Bs1 is
Similar to the auxiliary ball tip screw Bs2, the auxiliary ball tip screw Bs2 is formed of, for example, a male screw, and the interval between the mask holding frame MS1 and the base BP can be adjusted by adjusting the screwing depth. The screwing depth of the ball tip screw Bs1 is fixed by the nut Nt.

The position of the mask holding frame MS1 in the height direction with respect to the base BP is the V groove V1 and the ball tip screw Bs1.
This height is regulated by the mask opening / closing frame MS2.
The auxiliary V groove body V2 and the auxiliary ball tip screw Bs2 of the mask holding frame MS1 are adjusted to be separated from each other. Therefore, the mask holding frame MS1 and the mask opening / closing frame MS
When 2 is separated from the spring Sp, the tip of the auxiliary ball tip screw Bs2 separates from the auxiliary V groove V2, and the mask holding frame MS1 moves in the XY directions (see the arrow in FIG. 4) with respect to the mask opening / closing frame MS2. Can be made. Further, the auxiliary V-shaped groove body V1 and the V-shaped groove body V2 are assembled so that the relative positional deviation is ± 50 μm or less, and the tip of the auxiliary ball tip screw Bs2 is separated from the auxiliary V-shaped groove body V2. The amount of movement of the mask holding frame MS1 with respect to the mask opening / closing frame MS2 at this time is also configured to fall within this range.

A vacuum suction pad Vp2 is attached to the V-shaped groove V1, and the vacuum suction pad Vp2 is provided with a pipe line connected to a vacuum source as shown in FIGS. Then, the ball tip screw Bs1 is inserted into the V groove V1.
When is correctly entered, a vacuum is supplied to the above-mentioned pipe line to fix the ball point screw Bs1 to the V groove body V1. Further, as shown in FIG. 4, the V mounted on the base BP
In the groove body V1, the direction of the groove is the base B as shown in FIG.
It is arranged so as to intersect at one point Q on P. By intersecting the direction of the groove of the V groove body V1 at one point Q as described above, even if the mask stage MS and the base BP are thermally expanded, a straight line connecting the groove of each V groove body V1 and the point Q is formed. The angle is kept constant and the position of point Q does not change. Therefore, if the mask mark MAM is located at the point Q, the position of the mask mark MAM can be kept constant regardless of the thermal expansion of the mask stage MS and the base BP.

Next, the positioning operation of the mask stage of this embodiment will be described. FIG. 1 shows a state in which the mask stage MS is open. In this state, the mask holding frame MS1 is biased toward the mask opening / closing frame MS2 by the spring Sp provided on the pin Pn. For this reason,
The tip of the auxiliary ball tip screw Bs2 provided in the mask holding frame MS1 is inserted into the groove of the auxiliary V groove body V2 provided in the mask opening / closing frame MS2, and the mask holding frame MS
1 and the mask opening / closing frame MS2 have a predetermined positional relationship. That is, the positional relationship between the ball tip screw Bs1 and the auxiliary ball tip screw Bs2 and the V groove body V1 and the auxiliary V groove body V2 is in the state shown in FIG. 5 (a). In addition, in the figure
(i) shows the case where the mask opening / closing frame MS2 is not displaced, and (ii) shows the case where the mask opening / closing frame MS2 is displaced.

FIG. 2 shows a state in which the mask stage MS is closed, but the vacuum suction pads Vp1 and Vp2 are not yet supplied with the vacuum, and the mask stage MS is not pulled toward the base BP side. In this state, the auxiliary ball tip screw B provided on the mask holding frame MS1
The tip of s2 has entered the groove of the auxiliary V-groove V2,
Further, the tip of the ball tip screw Bs1 provided on the mask holding frame MS1 is in contact with the V groove V1 provided on the base BP, and the flat bush Bu2 provided on the mask opening / closing frame MS2 is in a vacuum state. It is not in contact with the bush Bu1 of the suction pad Vp1. That is, the positional relationship between the ball tip screw Bs1 and the auxiliary ball tip screw Bs2 and the V groove body V1 and the auxiliary V groove body V2 is the mask opening / closing frame MS.
If the position of 2 does not shift when opening and closing,
In the state of (i) and the position of the mask opening / closing frame MS2 is displaced during opening / closing, as shown in FIGS. 5 (b) and (ii), the ball tip screw Bs1 contacts the V groove body V1 by one side. It becomes a state.

FIG. 3 shows a state in which a vacuum is supplied to the vacuum suction pads Vp1 and Vp2 and the mask stage MS is pulled toward the base BP side. In this state, the suction pad Vp1 pulls the mask opening / closing frame MS2 toward the base BP side, the bush Bu1 of the suction pad Vp1 contacts the flat bush Bu2 of the mask opening / closing frame MS2, and the tip of the ball tip screw Bs1 is It enters into the groove of the V-shaped groove body V1. Here, as described above, the position of the mask holding frame MS1 in the height direction with respect to the base BP is regulated by the V groove body V1 and the ball tip screw Bs1, and this height is the auxiliary V groove of the mask opening / closing frame MS2. The height at which the body V2 and the auxiliary ball tip screw Bs2 of the mask holding frame MS1 are separated is adjusted. Therefore, the vacuum suction force of the suction pad Vp1 of the base BP is made larger than the force of the spring Sp of the pin Pn pressing the mask holding frame MS1 against the mask opening / closing frame MS2, and the mask opening / closing frame MS2 is drawn toward the base BP side. Then, the mask holding frame MS1 is pushed up by the ball tip screw Bs1, and the mask holding frame MS1 and the mask opening / closing frame MS2 are separated from each other.

For this reason, the spring Sp provided on the pin Pn
Is slightly contracted, the auxiliary ball tip screw Bs2 provided on the mask holding frame MS1 is separated from the auxiliary V groove body V2, and the mask holding frame MS1 becomes movable in the XY directions with respect to the mask opening / closing frame MS2. In this state, the ball tip screw Bs1, the auxiliary ball tip screw Bs2 and the V groove V
The positional relationship between the auxiliary V-shaped groove body V2 and the auxiliary V-shaped groove body V2 is as shown in FIG. 5C. Even if the position of the mask opening / closing frame MS2 is shifted when the mask stage MS is opened / closed, the balls provided on the mask holding frame MS1. The front screw Bs1 is completely set in the V groove body V1, and the mask holding frame MS1 is accurately positioned.

That is, in this embodiment, when the mask opening / closing frame MS2 is pulled toward the base BP side by the suction pad Vp1, the auxiliary ball tip screw Vp2 separates from the auxiliary V groove body V2 and the mask holding frame MS1 opens / closes the mask. Frame M
Since it can move freely in the X and Y directions with respect to S2,
Even if the position of the mask opening / closing frame MS2 is displaced, the ball tip screw Bs1 provided on the mask holding frame MS1 is completely set within the V groove body V1, and the mask holding frame MS1 is accurately positioned. As described above, in this embodiment,
When the mask opening / closing frame MS2 is pulled toward the base BP side, the mask holding frame MS1 is configured to be freely movable in the XY directions, and the mask holding frame MS1 is positioned by the ball tip screw Bs1 and the V groove body V1. ing. Therefore, the smaller the amount of movement of the mask holding frame MS1 in the XY directions, the more reliably and accurately the positioning can be performed.

To reduce the amount of movement of the mask holding frame MS1 in the XY directions as described above, the mask opening / closing frame MS2
Position of the mask holding frame MS1 with respect to the mask opening / closing frame MS2 and / or the mask opening / closing frame M
The position of the mask holding frame MS1 with respect to the base BP when S2 is fixed to the base BP may be adjusted. This adjustment can be performed as follows. For example, the mask holding frame M
XY of auxiliary ball tip screw Bs2 provided on S1
The position in the direction can be adjusted by a fixing screw B11 as shown in FIG. Then adjust as follows. (1) The relative positions of the mask holding frame MS1 and the base BP are determined by the ball tip screw Bs1 and the V groove body V1. (2) Loosen the fixing screw B11 shown in FIG. 6 and adjust the positions of the auxiliary ball tip screws Bs2 in the XY directions so that the balls at the tips of all the auxiliary ball tip screws Bs2 are auxiliary Vs.
The groove V2 is placed in a predetermined position. (3) The height of the auxiliary ball tip screw Bs2 is adjusted, and when the mask opening / closing frame MS2 is adsorbed by the vacuum adsorption pad Vp1, the auxiliary ball tip screw Bs2 moves the V groove body V2.
And a predetermined distance apart.

In the above embodiment, three V-grooves are used for positioning the mask holding frame MS1 with respect to the base BP and positioning the mask holding frame MS1 with respect to the mask opening / closing frame MS2. Instead of three V-grooves,
For example, the pivot bearing, the V groove body, and the flat body may be used. FIG. 7 is a diagram showing an example of the above-mentioned configuration, which shows a positioning mechanism of the mask holding frame MS1 by the base BP. In the figure, BP is a base, V
11 is a V groove body, P11 is a pivot bearing, F11 is a plane body, and the groove of the V groove body V11 is directed toward the center of the pivot bearing P1. Bs1 is a mask holding frame M
This is the ball at the tip of the ball tip screw provided in S1.

With the configuration shown in the figure, the position of the mask holding frame MS1 is restricted by the pivot bearing P11 and the V groove V11, and the mask holding frame MS1 can be positioned at a predetermined position with respect to the base BP. it can. Further, the positioning mechanism shown in FIG. 7 can be used instead of the auxiliary V-groove V2 provided in the mask opening / closing frame MS2, and the mask holding frame MS1 can be replaced with the mask opening / closing frame MS2 by using the mechanism shown in FIG. It may be configured to position with respect to. Furthermore, in the above-described embodiment, an example of using a ball tip screw in which a ball is provided at the tip of the screw is shown, but instead of the ball, a protruding structure having a curved tip may be used. , V-groove or pivot bearing may be used as long as they can be engaged at one point.

In the first embodiment described above, the rotating shaft Sh is used to open and close the mask stage MS.
Therefore, when the mask stage MS is closed, the center of the rotation axis Sh is located on a surface substantially equal to the ball position of the tip of the ball tip screw Bs1 when the mask stage MS is closed, and the mask holding frame MS1 is provided with the center. The ball tip screw Bs1 is configured to enter the V groove body V1 of the base BP as vertically as possible. The above structure has an advantage that the structure is relatively simple, but since the movement of the mask stage MS is an arc, when the ball tip screw Bs1 enters the V groove body V1, it does not necessarily become a vertical state, The front screw Bs1 may enter the V-shaped groove body V1 slightly obliquely, and the alignment accuracy may decrease. Further, since the movement is an arc, the respective turning radii connecting the center of the ball at the tip of the three ball tip screws Bs1 and the center of the rotation axis Sh are different. Therefore, the impact when the ball tip screw Bs1 comes into contact with the V groove body V1 also becomes different, and in some cases, the alignment accuracy may decrease.

In order to remedy the above-mentioned drawbacks, the second and third embodiments shown below are constructed so that the mask stage approaches the base BP as vertically as possible when the mask stage MS is opened and closed. is there. FIG. 8 is a diagram showing a second embodiment of the present invention, which shows an embodiment in which the mask stage MS is opened and closed by a link mechanism. It should be noted that although the drawing mainly shows the opening / closing mechanism of the mask stage MS and the work W for easy understanding, the mask holding frame MS1
The positioning mechanism of is the same as that shown in FIGS.

8A shows a state in which the mask stage is closed, and FIG. 8B shows a state in which the mask stage is opened. MS1 is a mask holding frame to which the mask M is adsorbed, and MS2 is a mask opening / closing. Frame, mask holding frame MS
1. The mask opening / closing frame MS2 constitutes the mask stage MS. The above-mentioned ball tip screw Bs1 is provided in the mask holding frame MS1, and when the mask is closed, the ball at the tip of the ball tip screw Bs1 fits into the V groove body V1 provided in the base BP. Further, the auxiliary ball tip screw Bs described above is attached to the mask holding frame MS1.
2 is provided, and when the mask stage is not completely closed, the ball at the tip of the auxiliary ball tip screw Bs2 is the auxiliary V groove body V2 provided in the mask opening / closing frame MS2.
To fit. LK1 and LK2 are link mechanisms, one ends of the link mechanisms LK1 and LK2 are rotatably attached to the mask opening / closing frame MS2, and the other ends of the link mechanisms LK1 and LK2 are support bodies SPT1 and SPT2 fixed to the base BP.
It is rotatably mounted on. Also, W is the work,
WS is a work stage, which is omitted in the figure, but as shown in FIG.
S is attached to the XYθ stage and the Z stage via a gap setting mechanism, and the work stage WS is XYθZ.
Driven in the direction.

In the above structure, when the mask stage MS shown in FIG. 8A is closed and the mask stage MS is lifted by a grip (not shown) or the like, the link mechanism L
K1 and LK2 rotate until they hit the stopper Stp,
The mask stage MS moves up as shown in FIG. In this state, the work W can be placed on the work stage WS or the work W can be exchanged. In this embodiment, since the mask stage MS is raised by utilizing the link mechanisms LK1 and LK2 as described above, the ball tip screw Bs1 provided on the mask holding frame MS1.
The ball at the tip end of moves in an arc shape and enters the V groove body V1. Therefore, as described above, the alignment accuracy may decrease. However, the link mechanism LK1,
Since LK2 is used, each ball tip screw Bs1
Move with the same radius of gyration. Therefore, when the mask stage is closed, the ball tip screw Bs1 moves to the V groove V
The same impact is exerted upon contact with No. 1, and the ball point screw Bs1 can be inserted into the V groove V1 more smoothly than in the first embodiment described above.

FIG. 9 shows a third embodiment of the present invention, which shows an embodiment in which the mask stage MS is moved in the Z direction to open and close. It should be noted that, in order to facilitate understanding, the figure mainly shows the mask stage M, as in FIG.
Although the opening / closing mechanism of S and the work W are shown, the positioning mechanism of the mask holding frame MS1 is the same as that shown in FIGS. In the figure, the same components as those shown in FIG. 8 are designated by the same reference numerals, FIG. 9A shows a state in which the mask stage MS is closed, and FIG. It shows the state. In this embodiment, instead of the link mechanisms LK1 and LK2 shown in FIG.
It differs from FIG. 8 in that a Z-direction moving mechanism ZD for moving the mask opening / closing frame MS2 in the Z direction (vertical direction in the figure) is provided.
Other configurations are the same as those of the embodiment of FIG.

In the structure of FIG. 9, when the mask stage MS is lifted from the closed state of the mask stage MS of FIG. 9A, the mask stage MS is moved by the Z-direction moving mechanism ZD as shown in FIG. To rise. In this state, the work W can be placed on the work stage WS or the work W can be exchanged. Instead of lifting the mask stage MS as described above, a drive means may be provided in the Z-direction moving mechanism ZD to raise the mask stage MS by electric power, hydraulic pressure, pneumatic pressure or the like. In this embodiment, since the mask stage MS is raised by using the Z-direction moving mechanism ZD as described above, the ball at the tip of the ball tip screw Bs1 provided on the mask holding frame MS1 moves vertically. Then, V groove body V
Go into one. Therefore, as described above, the alignment accuracy does not decrease. It should be noted that, as described above, the mask stage M can be simply moved by raising the mask stage MS.
The space between S and the work stage WS cannot be sufficiently opened, which may hinder work such as replacement of the work W.

Therefore, for example, as shown in FIG. 10, when the mask stage MS is rotatable about the Z-direction drive mechanism ZD when the mask stage MS is moving upward, the work stage WS can be rotated. The space can be opened, and the work W can be easily replaced. Further, instead of rotating the mask stage as described above, when the mask stage MS is raised,
The mask stage MS may be configured to slide to the right in the figure. Further, the mask stage MS may be opened and closed by using a guide mechanism. Although the mask stage of the proximity exposure apparatus has been mainly described in the above embodiments, the mask stage positioning mechanism of the present invention is not limited to the proximity exposure apparatus described above, and various apparatuses that require positioning accuracy during opening and closing. Can be applied to.

[0045]

As described above, in the present invention,
The following effects can be obtained. (1) When the mask opening / closing frame is open, the position of the mask holding frame with respect to the mask opening / closing frame is positioned by the first three-point pair base element, and when the mask opening / closing frame is closed, the first three-point pair base element Since the mask holding frame can be moved with respect to the mask opening / closing frame by releasing the pair and the position of the mask holding frame with respect to the base is positioned by the second three-point pair base, the position of the mask opening / closing frame Even if the mask shifts when opening and closing the mask, the mask holding frame can be accurately positioned with respect to the base. Therefore, the alignment accuracy can be improved by applying the present invention to a proximity exposure apparatus or the like that performs back surface alignment.

(2) The first and / or second three-point pair base element is composed of three protrusions having curved surfaces at their tips and three V-grooves having V-grooves, By arranging the central axes of the groove bodies so as to intersect at a predetermined point, even if the mask holding frame, the mask opening / closing frame, and the base are thermally expanded, the point where the line connecting the central axes of the V groove bodies intersects each other. It can be held in a fixed position. Therefore, by disposing the alignment marks of the mask at the intersecting points, the position of the alignment marks does not shift even if thermal expansion occurs, and the alignment accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration (No. 1) of a mask stage according to an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration (No. 2) of the mask stage according to the embodiment of the present invention.

FIG. 3 is a diagram showing a configuration (No. 3) of the mask stage according to the embodiment of the present invention.

FIG. 4 is an exploded perspective view of the mask stage according to the embodiment of the present invention.

FIG. 5 is a diagram showing a positional relationship between a ball tip screw and a V groove body.

FIG. 6 is a diagram showing a position adjusting structure of an auxiliary ball tip screw.

FIG. 7 is a view showing another embodiment of the mask holding frame positioning mechanism.

FIG. 8 is a diagram showing a second embodiment of the present invention using a link mechanism.

FIG. 9 is a diagram showing a third embodiment of the present invention using a Z-direction moving mechanism.

FIG. 10 is a diagram showing an embodiment in which a rotation mechanism of the mask stage is provided in FIG.

FIG. 11 is a diagram showing a configuration of a proximity exposure apparatus using surface alignment.

FIG. 12 is a diagram showing a cross-sectional structure of a vacuum suction pad.

FIG. 13 is a diagram showing a configuration of a proximity exposure apparatus using back surface alignment.

FIG. 14 is a view showing a mounting structure of a rotating unit of the mask stage in FIG.

FIG. 15 is a diagram illustrating a positioning method using a ball tip screw and a V groove body.

FIG. 16 is a view showing a case where the relative positions of the ball tip screw and the V groove body are displaced.

[Explanation of symbols]

 M Mask MS Mask stage MS1 Mask holding frame W Work BP Base Bs1 Ball tip screw Bs2 Auxiliary ball tip screw V1 V groove body V2 Auxiliary V groove body Vp1 Mask opening / closing frame suction pad Vp2 suction pad Pn pin Sp spring H1, H2, h1 Hole Sh Axis P11 Pivot bearing V11 V Groove F11 Plane plate Bu1 Bush (Spherical tip) Bu2 Flat bush B11 Adjustment screw LK1, LK2 Link mechanism ZD Z movement mechanism

Claims (3)

[Claims] 1. A mask stage comprising a mask holding frame for holding a mask and a mask opening / closing frame, wherein the mask holding frame is attached so as to be movable with respect to the mask opening / closing frame when the mask opening / closing frame is closed. A base for opening and closing the mask opening and closing frame, and the mask opening and closing frame and the base for closing the mask opening and closing frame, the mask holding frame and the mask opening and closing frame in a direction substantially perpendicular to the base surface. A mask stage positioning mechanism connected so as to move, wherein the mask holding frame and the mask opening / closing frame are provided with a first three-point pair element that enables a three-point pair of the two. The mask holding frame and the base are provided with a second three-point pair element that enables the pair of three-point pairs, and when the mask opening / closing frame is open, the second three-point pair element is used. Release the three-point pair The position of the mask holding frame with respect to the mask opening / closing frame is positioned by the first three-point pair base element, and when the mask opening / closing frame is closed, the three-point pair formed by the first three-point pair base element is released. The mask stage positioning mechanism is characterized in that the position of the mask holding frame with respect to the base is positioned by the second three-point pair substrate. 2. The first and / or second three-point pair base element is composed of three projections having a curved surface at the tip and three V-grooves having V-grooves, The mask stage positioning mechanism according to claim 1, wherein the central axes of the V-shaped grooves intersect each other at a predetermined point. 3. The first and / or second three-point pair base element, a first protrusion having a curved surface at the tip, and the first protrusion
Of the projection, the second bearing having a curved surface at the tip, the second bearing having a curved surface at the tip, and the center axis of the second bearing having the central axis directed substantially in the direction of the pivot bearing. 2. The mask stage positioning mechanism according to claim 1, comprising a groove body, a third projection body having a curved surface at its tip, and a flat body in contact with the third projection body.