JPH09306808A - Mask blank conductive structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To connect a mask blank to an earthing wire without giving deflection to the mask blank by a method wherein the knife edge, which is arranged to cut into the chamfer part on the surface side of the edge of the mask blank by a spring, is swingably attached adjacent to an upper clamping piece opposing to a lower clamping piece. SOLUTION: An upper clomp piece 37B and the two knife edges 38, arranged in the left and the right sides of the upper clamp piece 37B, are attached to a lower clamp piece 37A opposing to the lower clamp piece 37A through a shaft 36, and the upper clamp piece 37B ant the knife edges 38 are vertically movable on the shaft 36. Also, the knife edges 38 are engaged to the shaft 36, and they are energized in the same direction as the closing direction of the tip side of a clamp 31 by the twisted spring whose both ends are engage to the knife edges 38 and the upper clam piece 37B. The edge part of a mask plank 1 is pinched by the clamp 31, the knife edges 38 are made to bite into the chamfer part of the edge part of the mask plank 1 and it is earth connected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in an electron beam drawing apparatus for connecting a ground to a mask blank when setting the mask blank on a sample stage in order to prevent charge up of the mask blank. Mask blank conduction mechanism.

[0002]

2. Description of the Related Art When an earth is connected to a mask blank in an electron beam writer, a knife edge connected to the earth is generally used, and this knife edge is placed near the edge of the mask blank. By pressing against the metal thin film deposition surface formed on the surface side,
It was grounded.

When the mask blank is set directly on the sample stage without using the mask holder, the knife edge is placed on the sample stage so that the blade edge portion of the knife edge faces the sample stage. Then, the mask blank was pushed up from the back side to fix the mask blank, and at the same time grounded.

When the mask blank is set on the sample stage using the mask holder, a knife edge pivotally mounted on the mask holder,
The edge of the mask blank is sandwiched between the upper surface of the mask holder and the upper surface of the mask holder, which is pushed up by the force of the spring, and grounded. When setting the mask blank on the mask holder, the mask blank was slid parallel to the upper surface of the mask holder to bring the ground into contact with the surface of the mask blank near the edge.

As described above, in the conventional mask blank conduction mechanism, the back surface of the mask blank is pressed near the edge thereof against the sample stage, the mask holder, or the reference surface provided on the upper surface of the mask holder. So
If there is a gap between the back surface of the mask blank and the mask holder, there is a problem that the mask blank is bent by the pressing force applied from the front surface side when grounding the mask blank.

For example, the mask blank has an interval L on the back surface side.
If there is a gap δ between the back surface of the mask blank and the upper surface of the mask holder in the middle part of the fulcrum, it is assumed that the middle part is pressed with a knife edge and a deflection of δ is given. The strain Δ of the surface of the mask blank is given by Δ = 4tδ / L 2 where t is the thickness. Here, t = 5 mm, δ = 1 μm, L =
If it is 100 mm, Δ = 0.2 μm, and 0.2 μm of strain is generated on the surface of the mask blank.

[0007]

The present invention has been made in view of the above problems, and the present invention is a mask blank for connecting the ground to the mask blank without causing bending of the mask blank. It is intended to provide a conduction mechanism.

[0008]

According to the mask blank conduction mechanism of the present invention, when the mask blank is set on the sample stage of the electron beam drawing apparatus, the metal thin film deposition surface formed on the surface side of the mask blank is grounded. A clamp used for connecting, comprising an upper clamp piece and a lower clamp piece, the clamp being fixed to the mask blank by sandwiching the vicinity of the edge of the mask blank from the front surface and the back surface, and the upper clamp piece. A knife edge which is adjacent to the lower clamp piece and is swingably attached so as to face the lower clamp piece, and is arranged so as to bite into the chamfered portion on the surface side of the edge portion of the mask blank by a spring. And

In the mask blank conducting mechanism of the present invention, the vicinity of the end face of the mask blank is sandwiched by the upper and lower clamp pieces, and the knife edge facing the lower clamp piece bites into the chamfered portion on the surface side of the edge of the mask blank. Since the ground is provided, the mask blank is not bent by the force when the ground is brought into contact with the mask blank.

Further, if a spring provided on the knife edge between the upper clamp piece and the knife edge is used to apply an urging force that bites into the chamfered portion, the biting force is maintained even if the thickness of the mask blank changes. It can be almost constant.

When the mask blank is set on the mask holder by connecting the clamp to the tip of a swivel arm that can swivel in a plane parallel to the surface of the mask blank, the clamp is attached to the end portion of the mask blank. Since it can be released to the outside of the mask blank, the mask blank can be brought closer to the mask holder from above, workability is improved, and the risk of scratching the back surface of the mask blank can be reduced. In this case, the swivel axis perpendicular to the surface of the mask blank is supported by the mask holder on which the mask blank is set, and the swivel arm is attached to the swivel base.

Further, the clamp is attached to the tip of the revolving arm via an axis in a direction perpendicular to the surface of the mask blank so that the position in the direction perpendicular to the surface of the mask blank can be adjusted. With this structure, it is possible to prevent the mask blank from being deformed due to the variation in the thickness of the mask blank. If the clamp is configured to be attachable to and detachable from the tip of the arm, the clamp can be replaced according to the change in size of the mask blank.

[0013]

FIG. 1 shows an example of an embodiment of the present invention.
From now on, description will be made with reference to FIG. 1 is a plan view of a sample stage of an electron beam drawing apparatus equipped with a mask blank conduction mechanism according to the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG. In the figure, 10 is a sample stage, 20 is a mask holder, 1 is a mask blank, 11 is a height reference member for supporting the mask blank 1 at a predetermined height, and 30 is a mask blank conducting mechanism based on the present invention.

The mask blank 1 is set on the mask holder 20, and the mask holder 20 is set on the sample stage 10. The mask blank 1 is set in a mask holder 20 as described later at a mask setting position (not shown) arranged adjacent to the sample stage 10, and is carried onto the sample stage 10.

A plurality of height reference members 11 are arranged on the upper surface of the sample stage 10. These height reference members 11 penetrate the slit-shaped openings 21 provided in the mask holder 20, contact the lower surface of the mask blank 1, and support the mask blank 1. In this example,
Although a pin-shaped member is used as the height reference member 11, any other shape may be used as long as it supports the back surface of the mask blank. In addition, the mask holder 20 is provided with a roller-shaped support member 22 that also serves as a guide when setting the mask blank 1.

At the position corresponding to the end face of the mask blank 1 on the surface of the mask holder 20, three reference pins 23 for positioning the mask blank 1 at a predetermined position on a plane parallel to the surface of the mask holder 20. , 24, 25 and a pair of clampers 26 for pressing the mask blank 1 against these reference pins 23, 24, 25. Further, a mask blank conduction mechanism 30 according to the present invention is attached to the surface of the mask holder 20 at a position corresponding to the vicinity of the end surface of the mask blank 1.

3 and 4 are enlarged views of the mask blank conducting mechanism 30. As shown in FIG. 3 is a plan view, and FIG. 4 is a sectional view taken along line BB in FIG. As shown in FIG. 3 and FIG. 4, the mask blank conduction mechanism 30 includes the swivel arm 3
2, a clamp 31 including a lower clamp piece 37A and an upper clamp piece 37B, a knife edge 38, and the like.

The base of the swing arm 32 is a mask holder 2
0 through the horizontal axis 33 parallel to the upper surface of the mask holder 20
Is attached to a rotary shaft 34 that is perpendicular to the upper surface of the mask holder 20, and the rotary shaft 34 is supported by a bearing provided in the mask holder 20. Thereby, the swivel arm 32 can swivel in a plane perpendicular to the upper surface of the mask holder 20 and in a plane parallel to the upper surface of the mask holder 20.

A clamp 31 is attached to the tip of the revolving arm 32 via a shaft 35 so as to be vertically movable and rotatable. Further, at the tip of the swing arm 32, the shaft 3
5 is provided with a retaining screw 35A, and by loosening the retaining screw 35A, the clamp 31 is attached to the arm 32.
It can be removed from the tip of the and replaced.

By rotating the revolving arm 32 in a plane parallel to the upper surface of the mask holder 20 within a range limited by revolving amount regulating means (not shown), a solid line and a solid line in FIG. 3 respectively. As indicated by the chain double-dashed line, the clamp 31 is alternately switched between a standby position in which the clamp 31 escapes to the outside of the edge of the mask blank 1 and an operating position in which the tip of the clamp 31 enters a predetermined amount into the end of the mask blank 1. It's possible.

Next, the clamp 31 and the knife edge 38.
The structure of will be described. A shaft 36 parallel to the edge of the mask blank 1 is attached to the upper side of the lower clamp piece 37A, and similarly behind the shaft 36 (in the direction away from the edge of the mask blank 1, left in FIG. 4). A shaft 39 parallel to the edge of the mask blank 1 is attached. The upper clamp piece 37B and the two knife edges 38 arranged on the left and right of the upper clamp piece 37B are attached to the lower clamp piece 37A so as to face the lower clamp piece 37A via the shaft 36, respectively. Axis 3
It is possible to swing up and down with 6 as a fulcrum. Further, the upper clamp piece 37B is provided with the torsion spring 4 engaged with the shaft 39.
0 exerts an urging force in the direction of closing the tip end of the clamp, and the closing limit position is regulated by the stopper portion 41 integrally provided on the lower side of the upper clamp piece 37B as shown in FIG. It has become so.

Further, the knife edge 38 is engaged with the shaft 36, and both ends thereof are provided with the knife edge 38 and the upper clamp piece 37B.
In addition, the biasing force in the same direction as the direction in which the tip end side of the clamp 31 is closed (clockwise direction in FIG. 4) is applied by the respectively locked torsion springs 42. The rotation of the knife edge 38 due to this urging force causes the stopper portion 43 provided on the knife edge 38 to move the upper clamp piece 37.
It is regulated by contacting B. The biasing force of the torsion spring 42 is set to be smaller than the biasing force of the torsion spring 40 of the upper clamp piece 37B.

How to use the mask blank conducting mechanism will be described with reference to the sectional views of the clamp portion shown in FIGS. In addition, in FIG.
The state immediately before the edge of the mask blank 1 is sandwiched, FIG.
Clamps the edge portion of the mask blank 1 with the clamp 31 and inserts the knife edge 38 into the chamfered portion 1a of the same edge portion.
It shows the state that it is bitten into and grounded. In the figure,
Reference numeral 10 is a sample stage, 20 is a mask holder, 1 is a mask blank, 2 is a chromium vapor deposition film applied on the surface of the mask blank, and 3 is a resist film applied on the chromium vapor deposition film.

First, at a mask blank setting position (not shown) adjacent to the sample stage 10, the clamper 26 (FIG. 1) of the mask holder 20 is set to the unclamp position, and the mask blank conducting mechanism 30 is set. The mask blank 1 is placed on the roller-shaped support member 22 in the standby position shown by the solid line in FIG. Next, the clamper 26 is switched to the clamp position, and the mask blank 1
Is held against the reference pins 23, 24, 25.

Next, the base end side (the left end side in FIG. 4) of the upper clamp piece 37B is pressed from above to open the front end side of the upper clamp piece 37B against the torsion spring 40. Along with the movement of the upper clamp piece 37B, the knife edge 38
Moves in the direction of opening the tip side (counterclockwise direction in FIG. 4). In this way, with the upper clamp piece 37B and the tip side of the knife edge 38 open, the clamp 3
1 is moved to the operating position indicated by the chain double-dashed line in FIG. FIG. 5 shows the state at this time.

At this position, the upper clamp piece 37B
The force in the direction of releasing the tip of the upper clamp piece 37B is weakened, and the tip of the upper clamp piece 37B is gently closed by the biasing force of the torsion spring 40. With the movement of the upper clamp piece 37B, the knife edge 38 moves in the direction of closing the tip side thereof (clockwise direction in FIG. 4), and the knife edge 38 contacts the edge portion of the mask blank 1. Furthermore, the upper clamp piece 37
When B is closed, the knife edge 38 receives the biasing force of the torsion spring 42 and bites into the chamfered portion 1a on the upper surface side of the edge portion of the mask blank 1. At this time, the lower clamp piece 37A
Of the mask blank 1 contacts the lower surface side of the mask blank 1,
The pressing force of the knife edge 38 is received.

Further, by closing the upper clamp piece 37B, the pressing force of the knife edge 38 is increased,
This is until the tip portion of the upper clamp piece 37B reaches the surface of the mask blank 1, and the knife edge 38
The amount of relative movement of the above with respect to the upper clamp piece 37B is hardly affected by the thickness of the mask blank 1 and is maintained substantially constant. Therefore, even if the thickness of the mask blank 1 changes to some extent, the knife edge 38 is pressed against the mask blank 1 with a preset pressing force. As a result, the knife edge 38 penetrates the resist film 3 formed on the surface of the mask blank 1 to reach the chromium vapor deposition film 2, and electrically connects the chromium vapor deposition film 2 to the ground. FIG. 6 shows the state at this time.

When the tip portion of the upper clamp piece 37B comes into contact with the surface of the mask blank 1, the mask blank 1 is gripped by the tip portion of the lower clamp piece 37A and the clamp 31 is fixed to the mask blank 1. This fixing force is determined by the difference between the urging forces of the torsion spring 40 and the urging force of the torsion spring 42, because the urging force of the torsion spring 42 acts in the opposite direction to the upper clamp piece 37B. Therefore, the biasing force of the torsion spring 40 is set so that a gripping force suitable for fixing the clamp 31 to the mask blank 1 is obtained from the relationship with the biasing force of the torsion spring 42.

When the thickness of the mask blank 1 changes greatly, the gripping force deviates from an appropriate value and
Since the contact angle of the knife edge 38 also changes, it is necessary to replace it with another clamp portion that is dimensioned to the thickness of the mask blank 1. In this case, the swing arm 32
Loosen the retaining screw 35A attached to the tip of the shaft 3 attached to the bottom of the lower clamp piece 37A
5 is removed from the tip of the swivel arm 32, and the clamp part is replaced.

After the mask blank 1 is set on the mask holder 20 as described above, it is carried onto the sample stage 10 by using a carrying device (not shown), and as shown in FIGS. The mask holder 20 is lowered to a predetermined position on the sample stage 10 so that the mask holder 20 and the height reference member 11 arranged on the sample stage 10 do not interfere with each other. At this time, the mask blank 1 supported by the supporting member 22 of the mask holder 20 is slightly pushed up by the height reference member 11 protruding through the slit-shaped opening 21, as shown in FIG. After that, it is supported by the height reference member 11. At this time, in the mask blank conduction mechanism 30, the lower clamp piece 37A moves in the height direction with respect to the tip end portion of the revolving arm 32 by the sliding of the shaft 35, or the revolving arm 32 slightly moves upward by the horizontal shaft 33. It moves in the height direction together with the mask blank 1 by turning to.

In the above example, the mask blank 1 set on the mask holder 20 is slightly lifted from the upper surface of the mask holder 20 by the reference member 11 arranged on the sample stage 10, and the sample stage 10 is held. Taking a mask holder of the type set on the above as an example, the mask blank conducting mechanism 30 is attached to such a mask holder 20.
However, in the case of a mask holder in which the mask blank 1 set in the mask holder is fixed on the mask holder and cannot be lifted from the mask holder, the clamp 31 needs to be vertically movable. There is no. Further, in the case of the mask holder of the type in which the mask blank 1 is moved in parallel to the upper surface of the mask holder and set in the mask holder, it is not necessary to move the clamp 31 to the standby position, and the clamp 31 is fixedly arranged at the operating position. May be.

When the mask holder is not used, the mask blank conduction mechanism 30 may be directly attached on the sample stage 10. Furthermore, even if the thickness of the mask blank 1 changes to some extent, the knife edge 38
Although an example in which a torsion spring 42 is attached between the knife edge 38 and the upper clamp 37B is shown so that the pressing force of the screw is kept substantially constant, the torsion spring 42 is attached between the lower clamp piece 37A and the knife edge 38. It may be attached so as to generate a force.

[0033]

According to the mask blank conducting mechanism of the present invention, the knife edge for connecting the ground to the mask blank is arranged so as to be adjacent to the upper clamp piece and to face the lower clamp piece, and the mask blank is clamped. The grip of the edge and the knife edge bite into the chamfer on the surface side of the edge of the mask blank, resulting in a significant reduction in mask blank deflection due to the force connecting the mask blank to ground. It is possible to improve the accuracy of the mask pattern formed on the mask blank.

Since the knife edge is provided with a biasing force by a spring provided between the upper clamp piece and the knife edge, the biting force is set to a substantially predetermined value even if the thickness of the mask blank changes. It was possible to make an accurate ground connection.

Further, the above clamp is attached to the mask holder via the swivel arm, and the swivel arm is configured to be rotatable about an axis perpendicular to the surface of the mask holder. When setting the mask blank, it is possible to set the mask blank from above the mask holder without sliding on the mask holder, reducing the risk of scratching the mask blank and at the same time, causing dust generation. Can be removed.

[Brief description of drawings]

FIG. 1 is a plan view of a sample stage of an electron beam drawing apparatus equipped with a mask blank conduction mechanism according to the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is an enlarged plan view of a mask blank conduction mechanism based on the present invention.

FIG. 4 is a sectional view taken along line BB in FIG.

FIG. 5 is a sectional view of a clamp portion showing the operation of the mask blank conduction mechanism.

FIG. 6 is a sectional view of a clamp portion showing the operation of the mask blank conduction mechanism.

[Explanation of symbols]

1 ... Mask blank, 1a ... Chamfered part, 2 ...
・ Chromium vapor deposition film, 3 ... Resist film, 10 ... Sample stage, 11 ... Height reference member, 20 ... Mask holder, 21 ... Slit-shaped opening, 22 ... Roller -Shaped support member, 23, 24, 25 ... Reference pin,
26 ... Clamper, 30 ... Mask blank conduction mechanism, 31 ... Clamp, 32 ... Swivel arm, 33
... horizontal axis, 34 ... swivel axis, 35 ... axis, 35A
... Prevention screw, 36 ... shaft, 37A ... lower clamp piece, 37B ... upper clamp piece, 38 ...
Knife edge, 39 ... Shaft, 40 ... Torsion spring,
41 ... Stopper part, 42 ... Torsion spring, 43 ...
..Stoppers

Claims (5)

[Claims] 1. In a mask blank conduction mechanism for connecting a ground to a metal thin film deposition surface formed on the surface side of the mask blank when setting the mask blank on a sample stage of an electron beam drawing apparatus, an upper clamp piece and a lower portion. A clamp that is fixed to the mask blank by sandwiching the vicinity of the edge of the mask blank from the front surface and the back surface; and a swing piece that is adjacent to the upper clamp piece and faces the lower clamp piece. A mask blank conducting mechanism comprising: a knife edge attached to the chamfered portion on the front side of the edge of the mask blank by a spring, and a knife edge. 2. The knife edge is formed by a spring provided between the upper clamp piece and the knife edge,
The mask blank conduction mechanism according to claim 1, wherein the chamfered portion is configured to be provided with an urging force that bites into the chamfered portion. 3. The mask blank conduction mechanism is supported by a mask holder that holds the mask blank, and has a swivel axis in a direction perpendicular to the surface of the mask blank, and a base portion of the swivel axis is attached to the swivel axis. 2. The mask blank conduction mechanism according to claim 1, further comprising: a swivel arm that can swivel in a plane parallel to the swivel arm, wherein the clamp is attached to a tip end portion of the swivel arm. 4. The clamp is provided with an axis in a direction perpendicular to the surface of the mask blank, and is attached to the tip end portion of the pivot arm via the axis to adjust the position in the direction perpendicular to the surface of the mask blank. The mask blank conduction mechanism according to claim 3, which is possible. 5. The mask blank conduction mechanism according to claim 4, wherein the clamp is attachable to and detachable from a tip end portion of the revolving arm.