JPS62216227A - Mask holding device - Google Patents

Abstract

PURPOSE:To perform stable operation in any of liquid or gas atmosphere, reduced pressure or vacuum by providing a mask frame composed partly of a magnetic material, a permanent magnet, and a coil for cancelling the magnetic force of the magnet by energizing. CONSTITUTION:This mask holding device has a mask film 1, an annular permanent magnet 2 having a central axis (a), solenoid coils 3a, 3b wound around the axis (a), a yoke 4 for forming a magnetic circuit, a mask frame 5 composed of a magnetic material, and leads 6 for supplying a current to the coils 3a, 3b. In this structure, when the frame 5 is drawn to the magnet 2, a magnetic circuit is formed of the magnet 2, the yoke 4 and the frame 5, and the frame 5 is attracted to the magnet 2 and the yoke 4. Thus, since no operating portion is provided, high reliability is obtained. Since the energizing time of the solenoid is short, the quantity of heat is small to reduce the accuracy decrease due to thermal deformation to operate in all operation atmosphere such as gas, liquid and vacuum, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a mask holding device used in a bonding process, particularly a transfer process, for manufacturing semiconductor devices with highly integrated circuits. The present invention relates to a mask holding device capable of easily attaching and detaching a transfer mask in a gas-filled atmosphere or in a vacuum, and capable of holding the mask with high precision.

[Description of the Prior Art] As the degree of integration of circuits transferred onto semiconductor circuit elements increases, the width of lines constituting a circuit pattern has become narrower, and today a submicron order is required. In order to achieve this, it has become necessary to use ultraviolet rays, deep ultraviolet rays, soft X-rays, or particle beams such as ions or electrons for the irradiation energy used to transfer the circuit pattern. For this reason, it is necessary to use a special gas, such as nitrogen or helium gas, for the atmosphere in the optical path, or to create a vacuum at a pressure of 1xio Torr.

Conventionally, as this type of mask holding device, one configured as shown in FIGS. 5 and 6 is known.

FIG. 5 shows a cross-sectional view of a mask holding device using vacuum suction. This is for holding a mask by vacuum suction in a gas atmosphere. In the same figure, 1 is a mask, 1
0 is an exhaust pipe for connecting to an exhaust device (not shown), and 11 is an exhaust groove provided in the mask holding plate 12. In such an apparatus, gas in the exhaust groove 11 is exhausted through the exhaust pipe 10 while the mask 1 is in contact with the mask holding plate 12 . At this time, a pressure difference is created between the surrounding gas and the pressure inside the exhaust groove, and the mask is placed in a so-called vacuum suction state. However, in this case, atmospheric gas is absorbed and exhausted from the adsorption surface, resulting in problems such as a decrease in atmospheric gas pressure and an increase in gas consumption. In addition, there was also a drawback that the adsorption and holding power decreased in a reduced pressure gas atmosphere or in a vacuum, making it unusable.

FIG. 6 shows a cross-sectional view of the electromagnetic mask holding device. This type of device is disclosed in Japanese Patent Laid-Open No. 60-77424. In the figure, 3 is a solenoid coil for generating magnetic lines of force, 4 is a yoke for forming a magnetic path,
6 is a lead wire for energizing the solenoid coil 3. 13 is a cooling pipe for removing heat generated by the solenoid coil to the outside. In the state shown in FIG. 6, when the solenoid coil 3 is energized while the mask 1 is in contact with the yoke 4, the yoke 4 is energized and the mask 1 is magnetically attracted to the yoke 4. Next, when the electricity is turned off, the mask 1 is removed from the yoke 4. However, in the case of such devices, when the solenoid coil is energized, it generates heat due to Joule heat.
Since thermal distortion may occur in the mask, it is necessary to flow a coolant from a cooling device (not shown) into the cooling vibe 13 and to dissipate the heat to the outside. In other words, in a magnetic chuck with such a configuration, the excitation coil generates a lot of heat, which necessitates a cooling coil as in the conventional type described above, which increases the size of the entire device and requires complicated piping. . For this reason, there is a drawback that handling is complicated and manufacturing costs are also increased.

[Object of the Invention] In view of the above-mentioned problems of the conventional type, an object of the present invention is to provide a mask holding device that operates stably in a liquid or gas atmosphere, or in a reduced pressure or vacuum, and can be manufactured at a low cost. With the goal. Another object of the present invention is to provide a mask holding device that can be used in semiconductor manufacturing equipment that requires extremely fine and highly accurate transfer mask holding.

[Explanation of Examples] Hereinafter, the present invention will be explained in detail using the drawings.

FIG. 1 shows a cross-sectional view of a mask holding device according to an embodiment of the present invention. In the figure, 1 is a mask film, 2 is an annular permanent magnet with central axis a, 3a and 3b are solenoid coils each wound around central axis a, 4 is a permanent magnet and solenoid coil 3a, A yoke for forming a magnetic circuit together with 3b, 5 a mask frame made of magnetic material, and 6 solenoid coils 3a and 3b.
This is a lead wire for passing current through. The permanent magnet 2 is
It is polarized and magnetized in the vertical direction (direction along the central axis a). The magnetic flux emitted from the upper surface of the permanent magnet 2 passes through the yoke 4 and circulates to the lower surface of the permanent magnet 2. In the above configuration, when the mask frame 5 is brought close to the permanent magnet 2, a magnetic circuit is formed by the permanent magnet 2, the yoke 4, and the mask frame 5, and the mask frame 5 is attracted and attracted to the permanent magnet 2 and the yoke 4.

- et al. Now assume that the permanent magnet 4 is magnetized so that the upper surface is the N pole and the lower surface is the S pole (of course, it may be upside down). In order to remove the mask frame 5, currents are applied to the solenoid coils 3a and 3b in a clockwise direction and a counterclockwise direction, respectively, when viewed from the top surface of the permanent magnet 2. Then, the magnetic flux inside the permanent magnet 2 from the top surface to the bottom surface passes through the magnetic circuit,
The magnetic force of the magnet 2 is permanently canceled out, and no magnetic flux passes between the yoke 4 and the mask frame 5. Therefore, the adhesion force between the yoke 4 and the mask frame 5 is lost, and the mask frame 5 is separated from the yoke 4.

Note that the solenoid coil only needs to be energized when the mask frame is removed, and it only takes a very short time.

Further, as shown in FIGS. 2 to 4, the positions of the permanent magnet and the solenoid coil of the mask holding device shown in FIG. 1 may be changed as appropriate.

FIG. 2 shows another embodiment of the present invention, in which the permanent magnet 2 is arranged in the radial direction (
When the mask frame 5 is attracted, the yokes 4a and 4b are polarized and magnetized in the direction perpendicular to the center line.

A magnetic circuit is configured with the mask frame 5. When the mass 6 is detached from the frame, it is sufficient to apply a magnetic flux that offsets the magnetic flux of the permanent magnet 2 using the solenoid coil 3, as in the apparatus shown in FIG.

FIG. 3 is another embodiment of the present invention, and its operation and application are similar to those in FIG. 1.

Figure M4 is also another embodiment of the present invention, in which the permanent magnet 2 is polarized in the vertical direction (direction of the center line), and magnetic flux is generated only on the lower surface of the magnet, and on the outer circumference (the side far from the center line) and the inner circumference. The operation and application are the same as in FIG. 1, except that the magnetic poles are magnetized differently on the side (the side closer to the center line).

In addition, in the above description, the permanent magnet 2 and the yoke 4 can also be integrally molded with a plastic magnet.

Furthermore, the yoke 4 can also be omitted.

[Effects of the Invention] As explained above, according to the present invention, a mask frame at least partially made of a magnetic material, a permanent magnet capable of attracting the magnetic material directly or through a yoke, and a magnetic material that is attracted by energization. The main body of the mask holding device includes a coil that cancels out the magnetic force of the permanent magnet, so it has the following effects.

■High reliability is achieved as there are no moving parts.

■Since the energization time to the solenoid is short, the amount of heat generated is low.
Less accuracy deterioration due to thermal deformation.

■It can operate in any operating atmosphere such as gas, liquid, or vacuum, and is stable in an atmosphere that does not attenuate the light intensity even when using relatively long wavelength light sources such as soft X-rays. It is possible to operate the

■Since the structure is simple and can be formed into a flat shape, it is easy to attach and detach sensors necessary for exposure and positioning, and the peripheral mechanisms can be simplified and downsized.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a mask holding device according to an embodiment of the present invention, FIGS. 2 to 4 are cross-sectional views of a mask holding device according to other embodiments of the present invention, and FIG. Cross-sectional view of a mask holding device using vacuum suction FIG. 6 is a cross-sectional view of a conventional mask holding device using electromagnetic force. 1: Mask film, 2: Permanent magnet, 3: Solenoid coil, 4: Yoke,

Claims (1)

[Scope of Claims] 1. A mask holding device of a transfer device that irradiates irradiation energy onto a sensitive body through a mask and transfers a pattern formed on the mask onto the sensitive body, the mask holding device comprising at least one A mask holding device comprising a mask or a mask frame whose portion is made of a magnetic material, a permanent magnet capable of attracting the magnetic material directly or via a yoke, and a coil that cancels out the magnetic force of the permanent magnet by being energized.