JPH07169672A - X-ray mask positioning device - Google Patents

Abstract

PURPOSE:To enable further highly precise and easy positioning by further sticking a positioning member to a mask holding frame where a mask substrate is stuck. CONSTITUTION:A mask supporter 3 is stuck with adhesive to make the center thereof coincide with the center of an opening 2a and to make one side of an X-ray transmission region 5 approximately to one side of an outer circumference of a mask holding frame 2. A highly rigid positioning member 6 is stuck to one side of an upper part of the mask holding frame 2 along one side of the upper part. Each of both ends of the positioning member 6 is made to project from an outer circumference of the mask holding frame 2. A V-shaped cut-out 7 is provided to a lower side of one projection part and an L-shaped cut-out 8 whose one side extends in a horizontal direction is provided to a lower side of the other projection part. Furthermore, magnetic substances 9a, 9b, 9c are stuck to the rear of the mask holding frame 2 at approximately the same interval on a circumference forming a circle concentric with an opening 2a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an X-ray mask positioning apparatus, and more particularly to a mask positioning apparatus suitable for an X-ray exposure apparatus using synchrotron radiation as a light source.

[0002]

2. Description of the Related Art In recent years, in the field of exposure apparatuses for manufacturing semiconductor elements such as LSIs, X-rays such as synchrotron radiation which can be exposed with higher resolution as semiconductor elements become highly integrated. There have been proposed various exposure apparatuses utilizing the.

FIG. 5 shows the structure of a mask used in this type of exposure apparatus. 5A is a sectional view of the mask structure 110, and FIG. 5B is a front view thereof. The X-ray transparent film 1 is formed on the surface of the support 103 having the opening 105 in the central exposure area.
04 are formed. An X-ray absorber 101a is patterned and formed on the X-ray transparent film 104. Simultaneously with patterning, a mask mark 101 serving as a reference for alignment is formed.

Here, for example, the support 103 has a thickness of about 1
mm silicon substrate, X-ray transparent film 104 has a thickness of about 2 μm.
As the SiN or SiC film of m, the X-ray absorber 101a, a tungsten film or a tantalum film having a thickness of 1 μm or less is used. Since the support 103 is inconvenient to handle by itself, it is bonded to the holding frame 102 such as Pyrex glass having an opening in the exposure region and having a thickness of about 4 mm.

Generally, when a semiconductor element is manufactured using an exposure apparatus, it is necessary to align a wafer as a material to be processed and a mask with high accuracy on the order of 0.01 μm before exposure. . For this purpose, a mask positioning device that can position the mask holder 102 with good reproducibility is required in the order of μm, which is within the adjustment range of the mask-wafer alignment mechanism.

FIG. 6 shows the structure of a conventional mask positioning device. 3 provided on the mask stage base 106
The mask is positioned by bringing the side wall of the mask holding frame 102 into contact with the book positioning pins 107a to 107c. After the positioning is completed, the mask holding frame 102 is suction-held by a vacuum suction-holding mechanism (not shown), and is further accurately positioned and exposed by the alignment mechanism.

However, in the structure shown in FIG. 6, the mask holding frame 102 must be pressed against the remaining positioning pins 107c while pressing against the two positioning pins 107a and 107b. A complicated mechanism is required to perform this operation in the transport device. Further, when a trouble occurs in the vacuum suction holding mechanism, there is a risk that the mask structure may fall due to its own weight.

Inventions relating to a mask positioning mechanism that solves the above problems are disclosed in Japanese Patent Laid-Open Nos. 4-155815 and 5-15581.
No. 36587. FIG.
5815 shows the mask positioning mechanism disclosed in 5815.
The mask support 103 is fixed to the ring-shaped mask holding frame 102 made of heat-resistant glass or metal with an adhesive.

A mask stage base 117 for sucking and holding the mask structure 110 has a vacuum suction holding mechanism 118 connected to a vacuum suction source (not shown) and two cylindrical positioning pins 114, 115 in the horizontal direction. It is provided at intervals. The mask holding frame 102 is provided with two rectangular holes 113a and 113b for inserting the positioning pins 114 and 115, respectively.

The rectangular hole 113a on one side is formed so that each two sides are parallel in the horizontal and vertical directions, and the hole 1 on the other side is formed.
13b is formed in a direction obtained by rotating the hole 113a by 45 °. The holes 113a and 113b of the mask structure 110 formed in this manner are inserted into the mask stage base 117.
The positioning pins 114 and 115 are respectively inserted into the suspended state. After that, it is held by vacuum suction by the vacuum suction holding mechanism 118.

FIG. 8 shows a mask positioning mechanism disclosed in JP-A-5-36587. Mask support 103
Is fixed to the ring-shaped mask holding frame 102 made of Pyrex glass or the like with an adhesive.

The mask holding frame 102 includes a mask holding frame 1
At the height of the center of 02, a side 124a is formed by cutting inward from the outer periphery by about 4 mm toward the center, and the mask holding frame 102 is cut out right below the drawing to form an L-shaped cut. A notch 124 is provided.

The mask stage base 120 has a T-shaped positioning pin 122 and a T-shaped positioning pin 122.
And T on the opposite side of the mask stage base 120 in the radial direction.
The positioning pin 12 is located below a virtual line connecting the character positioning pin 122 and the center position of the mask stage base 120.
3 is provided.

The L-shaped notch 124 is abutted against the T-shaped positioning pin 122, and an arbitrary point on the outer periphery of the mask holding frame 102 is abutted against the positioning pin 123 for positioning. Then, it is held by vacuum suction by the vacuum suction groove 121.

[0015]

In the conventional example shown in FIGS. 7 and 8, the mask holding frame can be positioned and held on the mask stage base relatively easily. In this positioning mechanism, relative positional accuracy between the position of the positioning hole or notch provided in the mask holding frame 102 and the position of the mask mark 101 is required.

However, after patterning the X-ray absorber 101a, the mask support 103 is attached to the mask holding frame 102.
It is difficult to keep the positional accuracy within the required range by the method of adhering to.

As a mask positioning method, a method of positioning by providing a coarse movement mechanism in addition to the fine movement mechanism on the mask stage side can be considered, but the mask stage becomes complicated, the stage rigidity is lowered, and the position accuracy is deteriorated. There is a problem.

An object of the present invention is to provide a mask positioning device capable of positioning with higher accuracy and ease.

[0019]

The following description will be given with reference numerals in the drawings merely as an example for easy understanding, not in a limiting sense.

The mask structure of the present invention is a mask structure which is hung by the positioning means and is sucked and positioned by the mask fixing means having at least two positioning means provided so as to project from the close engagement surface. A body and a mask substrate (3) on which a mask pattern is formed
And a mask holding frame (2) to which the mask substrate is bonded
And is bonded to the mask holding frame so as to project from opposite sides of the mask holding frame, and one of the protruding portions is in contact with one of the positioning means provided in the mask fixing means at substantially two points. The notch (7) is provided, and the other protrusion has an engaging portion (8) formed so as to substantially contact with the other positioning means provided in the mask fixing means at one point. A positioning member (6).

Further, on the surface of the mask holding frame which engages with the mask fixing means, at least three magnetic bodies (9a, 9a,
9b, 9c) may be attached. The mask fixing means of the present invention is a mask fixing means for suspending and sucking and positioning a mask structure having a mask pattern formed thereon, the mask fixing means being provided so as to project from an engaging surface for sucking the mask structure. It includes one positioning means that supports the mask structure, and another positioning means that is provided so as to project from the engagement surface and that is capable of vertically moving a contact point with the mask structure.

[0022]

In the step of adhering the mask holding frame and the positioning member by further adhering the positioning member to the mask holding frame to which the mask substrate is adhered, the mask pattern and the positioning member formed on the mask substrate And can be relatively aligned. Therefore, it is possible to absorb the error in the relative position generated in the step of adhering the mask substrate and the mask holding frame. Thereby, the mask pattern and the positioning member can be accurately aligned and bonded.

By attaching a magnetic material to the mask holding frame, it can be attracted to the mask fixing means by a magnetic force. Since the area of the contact portion is much smaller in the suction by the magnetic force than the suction by the vacuum suction, it is less affected by the adhesion of dust, so that the suction can be performed with stable positioning with good reproducibility.

By making one of the positioning means provided on the mask fixing means movable up and down, fine adjustment of the rotational direction within the mask surface can be performed. As a result, the required stroke of the mask fine movement device can be reduced. Therefore, the mask fine movement device can be manufactured with high rigidity and high precision.

[0025]

1 (A) is a front view of a mask structure 10 according to an embodiment of the present invention, and FIG. 1 (B) is a sectional view taken along the chain line B1-B1.

An X-ray transparent film 4 is formed on the surface of a mask support 3 made of a silicon substrate having a thickness of 2 mm and a diameter of 3 inches. On the surface of the X-ray transparent film 4, the X-ray absorber 1a and the mask mark 1 for mask alignment are formed by patterning. As the X-ray transmission film 4, a SiN film or a SiC film having a thickness of about 2 μm is used. Also, X
A tungsten (W) or tantalum (Ta) film having a thickness of 1 μm or less is used for the line absorber 1a.

In the central portion of the mask support 3, a silicon substrate is etched from the back surface to form a substantially square opening to define an X-ray transmission region 5. Mask holding frame 2
Is a Pyrex glass plate having a thickness of 4 mm, and the outer periphery thereof has an octagonal shape in which each vertex of a square having a side length of about 127 mm is cut off into a right-angled isosceles triangular shape by a predetermined area. Further, an opening 2a having a diameter of about 56 mm is provided at the center thereof. The shape does not necessarily have to be circular and may be formed so as to include the X-ray transmissive region 5.

The center of the mask support 3 coincides with the center of the opening 2a, and one side of the X-ray transmission region 5 is the mask holding frame 2.
It is adhered with an adhesive so that it is almost parallel to one side of the outer circumference.

A highly rigid positioning member 6 having a length of about 155 mm, a width of about 17 mm and a thickness of about 3 mm is adhered to one side of the upper portion of the mask holding frame 2 along one side of the upper portion. Both ends of the positioning member 6 project from the outer periphery of the mask holding frame 2 by about 14 mm.

A V-shaped notch 7 is provided on the lower side of one of the protrusions. On the lower side of the other protruding portion, an L-shaped notch 8 having one side in the horizontal direction is provided. The positioning member 6 may be composed of left and right members, but the integrated structure has the advantage of requiring only one positioning operation.

The V-shaped notch may have any other shape as long as it makes contact with a positioning pin described later at substantially two points. For example, it may be trapezoidal. Further, it is formed so as to be substantially in contact with the positioning pin at two points, not parallel to each other and facing each other with a vertical plane interposed therebetween.
Other than the cutout portion may be used as long as it has two flat surfaces. For example, a triangular through hole may be used.

The L-shaped notch may have any other shape as long as it makes contact with the positioning pin at substantially one point. For example, it is not necessary to provide the notch as long as one plane formed substantially horizontally is defined.

On the back surface of the mask holding frame 2, magnetic bodies 9a, 9b, 9 are formed at substantially equal intervals on the circumference of a circle concentric with the opening 2a.
c is glued. The magnetic bodies 9a, 9b, 9c are provided so as to define a plane parallel to the mask surface, and are used to attract and fix the mask structure 10 to a mask chuck described later.

When adhering the positioning member 6 to the mask holding frame 2, a V-shaped notch 7 and an L-shaped notch 8 are provided.
By accurately bonding the mask support 1 so that the relative position to the mask mark 1 has a predetermined relationship, it is possible to absorb the error in the relative position generated when the mask support 3 is bonded to the mask holding frame 2.

Since the positioning member 6 has stronger mechanical strength than the mask support 3, the positioning member 6 can be positioned and bonded more easily than when the mask support 3 is bonded. Next, a mechanism for fixing the mask structure 10 to the mask chuck will be described with reference to FIGS. 2 and 3.

FIG. 2A shows a mask storage unit that stores the mask structure 10, a handling arm for transferring the mask structure 10 from the mask storage unit to the mask chuck, and a mask fine movement stage. A front view of the obtained mask chuck and FIG. 2B are cross-sectional views taken along chain line B2-B2.

The left side of FIG. 2A shows a mask storage unit for storing the mask structure 10. On the left side of the rail 11 in the drawing, a plurality of mask structures 10 are stored in the mask stocker 19 in a line in a direction perpendicular to the plane of the drawing. On the rail 11, a transfer chuck 1 that can move in the left-right direction in the drawing is provided.
2 is placed. The desired mask structure 1 to be exposed
The mask stocker 19 moves in a direction perpendicular to the paper surface so that 0 comes to a position where it is taken out by the transport chuck 12.
When the transfer chuck 12 moves to the left side, the mask structure 10 at a predetermined position is vacuum-sucked and held, and then moved to the right side.

The mask chuck 14 for fixing the mask structure 10 during X-ray exposure is shown on the right side of FIG. Mask positioning pins 15 and 16 for holding the mask structure 10 by mounting the V-shaped and L-shaped notches 7 and 8 provided on the mask structure 10 at predetermined positions of the mask chuck 14 are provided. Has been.

As shown in FIG. 2B, in the mask chuck 14, permanent magnets are used as magnetic poles at positions corresponding to the magnetic members 9a, 9b and 9c provided at three positions of the mask structure 10. Electromagnets 18a, 18b, 18c are provided, and the mask structure 10 can be attracted and fixed. The magnetic fields of the electromagnet and the permanent magnet are configured so that the directions thereof are opposite to each other. Therefore, when an electric current is passed through the coil, the attractive force of the permanent magnet is canceled, and when the electric current is cut off, the attractive force works.

On the left side of the mask chuck 14 of FIG. 2B, a mask fine movement stage 17 for holding a workpiece and performing final alignment with the mask structure 10 is arranged. At the time of exposure, X-rays are irradiated from the right side of the drawing and transmitted through the X-ray transmission region of the mask structure 10. At this time, a part of the X-rays is absorbed by the X-ray absorber formed in the X-ray transmissive region, so that the surface of the workpiece is exposed in a predetermined pattern.

A handling arm 13 is arranged between the mask storage section and the mask chuck 14. The handling arm 13 holds the desired mask structure 10 that has been moved to the right on the rail 11 by the transfer chuck 12 by vacuum suction at its tip, and rotates by a predetermined angle around the fulcrum, as shown in FIG. It can be carried to the position of the mask chuck 14 on the right side of A).

Next, referring to FIG. 3, the mask chuck 14 will be described.
The mask structure 10 carried to the position of the mask chuck 1
The mechanism held in No. 4 will be described. FIG. 3A shows a side view of the state in which the mask structure 10 is carried by the handling arm 13 to almost the front of the mask chuck 14. The mask structure 10 is held by the handling arm 13 in a state where the positioning member 6 and the mask positioning pin 15 are not in contact with each other. At this time, the electromagnet 18
A current is flowing through a, 18b, and 18c, and the attractive force of the permanent magnet is canceled.

Next, as shown in FIG. 3B, when the suction of the vacuum chuck of the handling arm is stopped to release the restraint of the mask structure, the mask falls by its own weight and comes into contact with the positioning pin to stop. To do. However, the handling arm is not always in a predetermined position because of friction caused by contact with the vacuum chuck.

Next, as shown in FIG. 3C, the compressed gas 21 is blown out from gas outlets (not shown) provided on both holding surfaces of the mask chuck 14 and the handling arm 13 to blow out the mask. 10 is in a floating state between the mask chuck 14 and the handling arm 13. At this time, the mask structure 10 falls by its own weight,
The V-shaped notch 7 provided in the positioning member 6 fits in the positioning pin 15. At the same time, the horizontal side of the L-shaped notch 8 not shown in FIG.

Next, as shown in FIG. 3D, when the blowing of the compressed gas on the mask chuck 14 side is stopped, the mask structure 10 is held by the positioning pins at a predetermined position and the mask is held by the mask chuck 14. It is in close contact with the surface. In this way, the mask structure 10 can be reliably positioned at a predetermined position.

Finally, the electromagnets 18a to 18a shown in FIG.
By turning off the current of 18c and magnetically attracting with a permanent magnet, the mask structure 10 can be closely fixed to a predetermined position of the mask chuck 14. Also, the mask structure 1
Since the falling direction of 0 is supported by the two positioning pins, the mask structure 10 does not drop even if the suction force of the mask is weakened due to some trouble.

In the above embodiment, the case where the positioning member 6 of the mask structure 10 is held by the positioning pins 15 and 16 fixed to the mask chuck 14 has been described, but the mask is attached to one of the positioning pins. A drive mechanism that can move vertically in the plane may be provided. For example, the positioning pin 16 may be an inchworm actuator.

FIG. 4 shows a structure of an inchworm type actuator 30 which can be used instead of the positioning pin 16. A mover 35 to which the upper slider 32, the advancing piezoelectric element 31, and the lower slider 33 are connected in this order is housed in a housing 34. The upper slider 32 is fixed by a locking lever 37, and the lower slider 33 is fixed by a locking lever 38. The locking levers 37 and 38 are rotationally driven by the locking piezoelectric elements 39 and 40, respectively, so that the moving element can be fixed or released.

For example, the traveling piezoelectric element 31 is stretched and displaced with only the lower slider 33 fixed, and then the upper slider 32 is fixed and the lower slider 33 is unfixed to advance. Gives a contraction displacement to. By repeating this operation, the mover 35 can be moved upward.

If the reverse operation is performed, the mover 35 can be moved downward. By using the inchworm-type actuator 30 instead of the positioning pin 16 of the mask chuck 14, the mask structure 10 is held by the positioning pin 15 and the inchworm-type actuator 30 and then finely rotated within the holding surface. You can

As described above, by slightly moving the positioning pin up and down, when the accuracy in the rotation direction in the mask plane is insufficient when the mask structure 10 is formed,
It can be corrected to the required accuracy.

Therefore, the fine movement stage of the mask only needs to have a minimum stroke and rotation, and the fine movement stage can be manufactured with high rigidity and high precision. Also,
Since the fine movement mechanism is an inchworm type actuator,
A high resolution and long stroke drive mechanism can be realized in an extremely small space. Furthermore, since the distance from the lock portion after the completion of positioning to the support point of the mask structure 10 is extremely short, there is no positional deviation or drift after locking and stable support is possible.

The present invention has been described above with reference to the embodiments.
The present invention is not limited to these. For example, it will be apparent to those skilled in the art that various modifications, improvements, combinations, and the like can be made.

[0054]

As described above, according to the present invention,
The X-ray mask structure can be reproducibly and easily aligned and fixed to the mask chuck.

[Brief description of drawings]

FIG. 1 is a front view and a sectional view of a mask structure according to an embodiment of the present invention.

FIG. 2 is a front view of a mask storage unit, a handling arm and a mask chuck according to an embodiment of the present invention, and a sectional view of the handling arm and the mask chuck.

FIG. 3 is a side view of a mask chuck and a handling arm according to an embodiment of the present invention.

FIG. 4 is a sectional view of an inchworm actuator according to an embodiment of the present invention.

FIG. 5 is a sectional view and a front view of a mask structure according to a conventional example.

FIG. 6 is a perspective view of a mask positioning device according to a conventional example.

FIG. 7 is a perspective view of a mask positioning device according to another conventional example.

FIG. 8 is a perspective view of a mask positioning device according to still another conventional example.

[Explanation of symbols]

 1 mask mark 1a X-ray absorber 2 mask holding frame 2a opening 3 mask support 4 X-ray transparent film 5 X-ray transparent region 6 positioning member 7 V-shaped notch 8 L-shaped notch 9a, 9b, 9c magnetic Body 10 Mask structure 11 Rail 12 Transfer chuck 13 Handling arm 14 Mask chuck 15, 16 Positioning pin 17 Mask fine movement stage 18a, 18b, 18c Electromagnet 19 Mask stocker 20, 21 Compressed gas 30 inch worm actuator 31 Piezoelectric element for moving 32 Upper slider 33 Lower slider 34 Housing 35 Moving element 37, 38 Locking lever 39, 40 Locking piezoelectric element 101 Mask mark 101a X-ray absorber 102 Mask holding frame 103 Mask support 104 X-ray transparent film 105 Opening 106 Masks Page 107a, 107b, 107c Positioning pin 110 Mask structure 113a, 113b Hole 114, 115 Positioning pin 117 Mask stage base 118 Vacuum suction holding mechanism 120 Mask holding frame 121 Vacuum suction holding mechanism 122 T-shaped positioning pin 123 Positioning pin 124 L-shaped Notch 124a L-shaped notch one side

Claims (3)

[Claims] 1. A mask fixing means having at least two positioning means provided so as to project from a close engagement surface,
A mask structure (3), which is hung by the positioning means and is sucked and positioned, wherein a mask substrate (3) having a mask pattern formed thereon, and a mask holding frame (2) to which the mask substrate is adhered, The mask holding frame is adhered to the mask holding frame so as to project from opposite sides of the mask holding frame, and one of the protruding portions has a notch portion that substantially contacts with one positioning means provided in the mask fixing means at two points. (7) and a positioning member (8) having an engaging portion (8) formed on the other protrusion so as to substantially contact the other positioning means provided on the mask fixing means at one point. 6) A mask structure including and. 2. Further, at least three magnetic bodies (9) are provided on the surface of the mask holding frame which engages with the mask fixing means.
A mask structure according to claim 1, wherein a, 9b, 9c) are attached. 3. A mask fixing means for suspending and sucking and positioning a mask structure having a mask pattern formed thereon, the mask fixing means protruding from an engaging surface for sucking the mask structure,
Mask fixing means including one positioning means that supports the mask structure, and another positioning means that is provided so as to project from the engagement surface and that is capable of vertically moving a contact point with the mask structure.