JP2001351838A - Charged particle beam exposure device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charged particle beam exposure device which is free from fluctuation of magnetic field on an optical axis even when a magnet track movement type linear motor is used. SOLUTION: A coil 4 which is bared in accordance with a position of a magnet track 5 is generated. A prescribed magnetic field is formed by making a prescribed current flow to a prescribed coil among the bared coils 4. Then, a magnetic field from the coil acts on an optical axis as shown by a magnetic force line 7. Meanwhile, a magnetic field generated by a permanent magnet of the magnet track 5 acts on an optical axis as shown by a magnetic force line 6 and finally the sum of magnetic field shown by magnetic force lines 6, 7 functions on an optical axis. If the sum of magnetic field shown by the magnetic force lines 6, 7 is made fixed regardless of a position of the magnet track 5 by adjusting a current to be made to flow to the bared coil 4, a magnetic field on an optical axis does not vary due to movement of the magnet track 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a charged particle beam exposure apparatus using a linear motor for driving a reticle stage, a wafer stage, and the like.

[0002]

2. Description of the Related Art In recent years, an exposure apparatus using a charged particle beam such as an electron beam has been developed with miniaturization of a semiconductor element. Since a charged particle beam such as an electron beam has a shorter wavelength than light, a finer shape than light can be exposed.

[0003] For example, in the case of an electron beam exposure apparatus of the division exposure transfer system, during exposure, a reticle serving as an original of a circuit and a wafer are driven in synchronization with each other, and a circuit pattern at a predetermined position on the reticle is moved to a predetermined position on the wafer. Exposure transfer to the position.

The reticle and wafer are mounted and driven on stages called a reticle stage and a wafer stage, respectively. A linear motor is often used to drive the stage. In a linear motor, a coil track in which coils are arranged in a row and a magnet track in which permanent magnets are arranged relatively move. Since a large current flows through the coil, cooling is necessary, and a method of forcibly convection the refrigerant by a pump is often used.

There are two types of linear motors: a magnet track moving type in which a coil track is fixed and a magnet track moves, and a coil motor moving type in which a magnet track is fixed and a coil track moves. Conventionally, a coil track moving type is often used. An example is shown in FIG.

[0006] A reticle stage 13 is provided between the lens barrels 11 and 12 of the electron beam optical system.
Is installed. The reticle stage 13 is driven by a linear motor 15. The linear motor 15 includes a fixed magnet track 16 and a reticle stage 13.
And a moving coil track 17. For cooling the coil of the coil track 17,
A hose 18 for supplying a coolant is connected to the coil track 17.

[0007] A wafer stage 19 is provided below the lens barrel 12.
Is provided, and the wafer 20 is mounted thereon. The wafer stage 19 is driven by a linear motor 15 '. The linear motor 15 'has the same configuration as the linear motor 15. In the drawings, both the reticle stage 13 and the wafer stage 19 show only a one-way drive system.
Each stage is provided with a drive system that drives in each axis direction and rotates in a plane parallel to the xy plane in a yz orthogonal coordinate system.

[0008] The reason for using the coil track moving type for moving the stage is to avoid fluctuations in the magnetic field on the optical axis. In other words, when a magnet track moving type is used, the magnetic field from the permanent magnet constituting the magnet track changes on the optical axis with the movement of the magnet track accompanying the movement of the stage, and therefore, according to the position of the stage. The trajectory of the electron beam changes.

On the other hand, if a coil track moving type linear motor is used, no current flows through the coil during exposure, so that even if the position of the coil track changes, there is no effect of the magnetic field generated by the coil. Since the magnetic field of the permanent magnet is kept constant since the coil track is fixed, the trajectory of the electron beam does not change according to the position of the stage.

However, in the coil track moving linear motor, when the coil track 17 moves, it must move while dragging the hose 18 for supplying the cooling refrigerant. Since the electron beam cannot pass through the atmosphere, the reticle stage 13 and the wafer stage 19
Both are arranged in a vacuum chamber. In order to maintain a good degree of vacuum, a member that generates a large amount of outgas cannot be placed in the vacuum chamber.

However, a hose for supplying a refrigerant generally has a large outgas, and a hose with a small outgas is very hard and hard to deform. Therefore, in a conventional device, as shown in FIG. 2, the hose 18 is bent into a U-shape,
When the stage is driven, care is taken so that the hose 18 is smoothly dragged. However, with the recent miniaturization of semiconductor elements, the positional accuracy required for the stage has also increased, and the stage position error due to the drag of the hose has become a problem.

As a countermeasure, as shown in FIG. 3, the use of a magnet track moving linear motor that moves a magnet track that does not require cooling and fixes a coil track has been studied. 3, the same components as those shown in FIG. 2 are denoted by the same reference numerals. As shown in FIG. 3, the reticle stage 13,
The wafer stage 19 is connected to the magnet track 16, and the magnet track 16 moves to drive each stage. Since the coil track 17 requiring cooling is fixed, the hose 18 is also fixed. Since the moving magnet track 16 does not need to be cooled, the occurrence of the stage position error caused by the hose drag described above is prevented.

[0013]

However, when a linear motor of a magnet track moving type is used, as described above, the magnetic field from the permanent magnet changes on the optical axis as the position of the permanent magnet fluctuates. The problem occurs. This is shown in FIG. 4, the same components as those shown in FIG. 2 are denoted by the same reference numerals. When the magnet track 16 is at the position shown by the solid line, the magnetic flux generated from the permanent magnet is as shown at 22, and when the magnet track 16 is at the position shown by the broken line, it is generated by the permanent magnet. The magnetic flux
2 '. The direction and size at the optical axis position in the lens barrel 11 or 12 are determined by the magnet track 1.
6, and the electron beam 21 bends in different directions accordingly, resulting in an exposure transfer error. Therefore, there is a problem that accurate exposure transfer cannot be performed.

The present invention has been made in view of such circumstances, and provides a charged particle beam exposure apparatus in which a magnetic field on an optical axis does not fluctuate even when a magnet track moving linear motor is used. As an issue.

[0015]

According to a first aspect of the present invention, there is provided a charged particle beam exposure apparatus having a mechanism for moving a stage using a linear motor, wherein the linear motor includes a magnet track moving mechanism. Type
A charged particle beam exposure apparatus (Claim 1) is provided with a coil for compensating a magnetic field fluctuation on the optical axis that occurs with movement of a magnet track.

In this means, since a coil is provided for compensating the magnetic field fluctuation on the optical axis caused by the movement of the magnet track, the current flowing through this coil is changed according to the movement of the magnet track. The sum of the magnetic flux generated by the coil and the magnetic flux generated by the magnet track can always be kept constant on the optical axis. Therefore, even if the magnet track moves, the magnetic field on the optical axis is kept constant, so that the trajectory of the charged particle beam does not change, and the accuracy of exposure transfer and drawing can be increased. In the present means (claim 1), the charged particle beam exposure apparatus includes not only an exposure transfer apparatus but also a drawing apparatus.

A second means for solving the above-mentioned problems is as follows:
The first means, wherein a coil of a coil track of the linear motor is used as the coil (Claim 2).

In a magnet track moving linear motor, the length of the coil track is longer than the length of the magnet track. Therefore, there is a coil that does not drive the magnet track. In this means, a current is caused to flow through the coils that do not drive the magnet tracks, thereby compensating for magnetic field fluctuations on the optical axis that occur with the movement of the magnet tracks. Therefore, there is no need to provide special coils,
The structure becomes simple.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows Embodiment 1 of the present invention.
FIG. 3 is a schematic diagram showing a linear motor and a lens barrel for driving a stage in an example of the electron beam exposure apparatus. In FIG. 1, 1 is a lens barrel of an electron beam optical system, 2 is an electron beam, 3 is a coil track, 4 is a coil, 5 is a magnet track, and 6, 7, and 8 are lines of magnetic force.

When the magnet track 5 is used for a movable part, it is necessary to keep the interaction length between the magnet track 5 and the coil track 3 constant.
Needs to be longer than the magnet track 5.
Its length is equal to or longer than the entire length of the range in which the magnet track 5 moves. Here, as shown in FIG. 1A, when the magnet track 5 moves to the front, the coil 4 of the coil track 3 at the back is exposed.

At this time, a predetermined magnetic field is generated by applying a predetermined current to a predetermined coil of the exposed coil 4. The energized coils are shown in black in the figure. Then, the magnetic field from the coil acts on the optical axis as shown by the magnetic field lines 7. On the other hand, the magnetic field generated by the permanent magnet of the magnet track 5 acts on the optical axis as shown by the magnetic field lines 6, and eventually the sum of the magnetic fields shown by the magnetic field lines 6 and 7 acts on the optical axis. .

As shown in FIG. 1 (b), when the magnet track 5 moves to the back, a predetermined current is applied to a predetermined one of the exposed front side coils 4, thereby A predetermined magnetic field is generated. The energized coils are shown in black in the figure. Then, the magnetic field from the coil 4 acts on the optical axis as shown by the magnetic force lines 8.
On the other hand, the magnetic field generated by the permanent magnet of the magnet track 5 acts on the optical axis as shown by the magnetic field lines 6, and eventually the sum of the magnetic fields shown by the magnetic field lines 6 and 8 acts on the optical axis. .

The magnet coil 5 is selected by appropriately selecting the exposed coil 4 from which the current flows, and by setting the appropriate amount of the current to flow.
The sum of the magnetic field generated by the permanent magnet and the magnetic field generated by the coil 4 is constant on the optical axis regardless of the position of the magnet track 5. As a result, the electron beam 2 is always affected by a constant magnetic field. Therefore, if the electron beam optical system is set in advance in consideration of the influence of the magnetic field, the electron beam 2 can be accurately determined regardless of the position of the magnet track 5. Exposure transfer can be performed.

In practice, since the magnet track 5 moves continuously, the optimum current of each coil at each position is measured in advance, and during actual exposure, the magnet track 5 is moved. Accordingly, it is necessary to continuously change the current flowing through each coil.

In the above-described embodiment, the magnetic field is generated by using the coil 4 of the coil track 3. However, a row of coils dedicated to correction may be provided near the linear motor, and the magnetic field may be corrected by using the coil. .

[0026]

As described above, according to the first aspect of the present invention, even when the magnet track moves, the change in the magnetic field on the optical axis can be suppressed to a small value. Therefore, it is possible to configure a magnet track moving type stage which has been considered difficult. In the stage configuration, it is not necessary to drag a hard hose, so that the positional accuracy of the stage can be improved.

According to the second aspect of the present invention, since there is no need to provide a special coil, the structure is simplified.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a linear motor for driving a stage and a lens barrel in an electron beam exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic view showing a stage and a lens barrel of an electron beam exposure apparatus using a conventionally used coil track moving linear motor.

FIG. 3 is a schematic diagram showing a stage and a lens barrel of an electron beam exposure apparatus using a magnet track moving linear motor.

FIG. 4 is a schematic diagram showing a problem when a linear motor of a magnet track moving type is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Electron beam optical system column 2 ... Electron beam 3 ... Coil track 4 ... Coil 5 ... Magnet track 6, 7, 8 ... Magnetic field lines

Claims (2)

[Claims] 1. A charged particle beam exposure apparatus having a mechanism for moving a stage using a linear motor, wherein the linear motor is of a magnet track moving type, and an optical axis generated as the magnet track moves. A charged particle beam exposure apparatus comprising a coil for compensating the above magnetic field fluctuation. 2. The charged particle beam exposure apparatus according to claim 1, wherein a coil of a coil track of the linear motor is used as the coil.