JP2005209791A - Electric operating device in vacuum - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem of an influence of radiation in an exposure device that operates a linear motor or the like in a vacuum chamber. <P>SOLUTION: A means for measuring the degree of a vacuum is provided in a vacuum chamber, thereby changing the operation state of a linear motor on the basis of a Paschen's law according to the measured degree of the vacuum. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an in-vacuum electric operation apparatus having a vacuum chamber, and is suitable for an exposure apparatus having a vacuum chamber, for example.

  The recent rapid development of semiconductor devices has led to a dramatic improvement in the performance of various information devices equipped with these devices, and is dramatically changing our lives. Supporting this development is the semiconductor manufacturing technology, and the exposure apparatus is the core of the technology.

  In recent years, with the miniaturization of semiconductor device rules, the exposure light source has shifted to the short wavelength region, and development of a light source in the soft X-ray region called i-ray, DUV light, and further EUV light is being promoted. . However, since EUV light has the property of colliding with and scattering air molecules in the air atmosphere, an exposure device equipped with this light source is equipped with an optical element, a substrate such as a wafer, or a reticle or the like. The periphery of the stage must be placed in a vacuum atmosphere.

As an example of an exposure apparatus having a vacuum atmosphere, for example, one described in Patent Document 1 can be cited. FIG. 5 is a view showing a wafer stage of the exposure apparatus described in Patent Document 1. In FIG. The wafer stage is driven by a linear motor (not shown), and electric power is supplied to the linear motor from an external power supply means (not shown).
JP 2001-297967 A

  In an in-vacuum electric operation apparatus that operates an electric load in a vacuum environment, for example, when operating by supplying a high voltage to an electric load such as a linear motor, a plurality of conductive electric elements having a potential difference ( Discharges in conductors, connection terminals, etc.) can be a problem. Therefore, there has been a demand for an apparatus that reduces the possibility of discharge at an electrode or terminal block of an electrical load such as a linear motor.

  The present invention has been made in view of such circumstances, and an object thereof is to reduce the influence of discharge in the vacuum chamber in an in-vacuum electric operation apparatus that operates an electric load in the vacuum chamber.

  In order to achieve the above-mentioned object, in the present invention, an in-vacuum electric operating device that operates an electric load in a vacuum chamber has a vacuum degree measuring means for measuring a vacuum degree in the vacuum chamber, and the vacuum degree The operating state of the electrical load is changed according to the degree of vacuum measured by the measuring means.

  The in-vacuum electric operation apparatus is preferably an exposure apparatus. In that case, an electric load includes, for example, a linear motor that drives a stage apparatus in a vacuum chamber. Changing the operating state of the electrical load preferably decelerates or stops the stage device by reducing the current flowing through the linear motor.

  ADVANTAGE OF THE INVENTION According to this invention, the influence by the discharge in a vacuum chamber can be reduced in the electric operation apparatus in a vacuum which operates an electrical load in a vacuum chamber.

  FIG. 1 is a schematic block diagram showing a stage apparatus of an exposure apparatus according to the first embodiment. The stage device is disposed in the vacuum chamber 19. The stage device includes a linear motor coil 4 in which coils of a plurality of phases (four phases in FIG. 1) are arranged in a straight line in the stage moving direction (Y direction). The linear motor coil 4 is supported by a coil support member 3, and a pair of guides 2 are provided in parallel with the Y direction. The guide 2 is provided with a hydrostatic bearing 6 on a plane perpendicular to the Z direction and a plane perpendicular to the X direction, and the stage top plate 1 as a moving stage is guided by the hydrostatic bearing 6 so as to be movable in the Y direction. Is done. Nitrogen or helium is used as a supply gas for the hydrostatic bearing 6, and a gas recovery mechanism for recovering these gases is used around the hydrostatic bearing 6.

  A movable magnet 5 is attached to the stage top 1, and the movable magnet 5 is configured by arranging two pairs of permanent magnets alternately in the Y direction with different polarities. Further, a mirror 7b is provided on the upper surface of the stage top plate 1, and the position of the stage top plate 1 is detected by the mirror 7b and the laser length measuring device 7a.

  The motor coil wire 8 drawn out from the linear motor coil 4 is temporarily fixed to the terminal block 9, connected to the motor power line 10, and connected to the power feeding means 24 via the connector 13 and the feedthrough connector 18.

  The stage apparatus is provided with a sensor 11 such as a limit sensor or an acceleration sensor, and a sensor cable 12 drawn from the sensor 11 is connected to a signal line 14 via a connector 13. These signal lines 14 are amplified by an amplifying element 16 such as an operational amplifier mounted on a printed circuit board 15 and read into the position control means 23 via the connector 13 and the feedthrough connector 18. Similarly, the signal from the laser length measuring instrument 7a is read into the position control means 23 via the connector 13 and the feedthrough connector 18.

  Thus, the sensor signal on the stage top plate 1 is sent to the position control means 23 fixed outside the stage apparatus, and sent to the linear motor coil 4 as a current through the power feeding means 24.

  When operating in a vacuum environment by supplying a high voltage to an electrical load (for example, a linear motor as described above), between conductive electrical elements having a potential difference (for example, between two poles of the terminal block 9 or a connector) 13), the discharge start voltage Vs changes greatly compared to the atmosphere. According to Paschen's law, when the pressure is P and the distance between the conductive electric elements is D, the discharge start voltage Vs is a function of PD.

  FIG. 3 is a diagram showing Paschen's law, where the vertical axis is Vs and the horizontal axis is PD. As can be seen from the figure, Vs varies depending on the type of gas, but for each gas, PD takes a minimum value in the vicinity of 1.0 [Pa · m]. Although not shown, in the case of helium, Vs becomes a minimum value of 156 V when the value of PD is about 5.3 [Pa · m], and in the case of nitrogen, the value of PD is about 0.89 [Pa · m]. In this case, Vs has a minimum value of 250V. This minimum value is called the Paschen minimum value. Paschen's law is valid if the electrode spacing is tens of cm or less.

  Now, in the EUV exposure apparatus or the like, it is necessary to operate the apparatus at a high vacuum level of at least 10 −5 Pa or more due to the above-described restrictions on outgas. Is done. Therefore, in light of Paschen's law, the possible distance between the electrically conductive elements around the electrical load is on the order of several meters at the maximum and on the order of 10-3 meters, so that The range in which the PD value can be taken between the conductive electric elements is on the order of 10-5 Pam to 10-8 Pam, and clearly corresponds to the left side of the minimum value of the discharge start voltage curve in FIG.

  On the other hand, the supply voltage to the electrical load, but in order to achieve higher throughput of recent exposure equipment, high-speed and high-acceleration of the stage is progressing, the generation of large acceleration force and back electromotive force when moving at high speed Therefore, it is necessary to supply a supply voltage on the order of several hundred volts.

  Therefore, in the EUV exposure apparatus, in a state where the target degree of vacuum is maintained, the discharge start voltage of helium or nitrogen is clearly higher than the supply voltage, and thus no discharge occurs.

  However, in the unlikely event that the degree of vacuum decreases and the pressure of the supply gas increases, the discharge start voltage Vs moves from the PD value to the minimum value of the Paschen curve, so that Vs falls below the supply voltage, and the conductive A discharge phenomenon or the like occurs between the conductive electrical elements.

  Therefore, in the present invention, the vacuum degree measuring means 22 is disposed in the vacuum chamber 19, and when the measured degree of vacuum falls below a predetermined degree of vacuum and there is a risk of discharge breakdown, the position control means 23 electrically The stage is decelerated or stopped by changing the current supplied to the linear motor as a load. Further, after the degree of vacuum in the vacuum chamber 19 exceeds a desired value and there is no danger of vacuum discharge, the stopped stage is operated again. This prevents discharge and enables stable operation. Here, the predetermined value is a degree of vacuum at which a discharge phenomenon or the like can occur between the conductive electrical elements obtained based on the above-mentioned Passion law, and can vary depending on the design.

  In the present embodiment, an example is shown in which the stage device is arranged in the vacuum chamber 19, but in this configuration, even if the projection system of the exposure apparatus is arranged in the vacuum chamber 19, only the stage device is placed in the vacuum chamber 19. A configuration arranged in the above may be used.

  FIG. 3 shows an exposure apparatus for manufacturing semiconductor devices in which a stage apparatus similar to the above is used as a wafer stage.

  This exposure apparatus is used for manufacturing a semiconductor device such as a semiconductor integrated circuit or a device in which a fine pattern is formed such as a micromachine or a thin film magnetic head, and is applied on a semiconductor wafer W as a substrate through a reticle as an original plate. Projection lens 503 (exposure light as exposure energy from illumination system unit 501 (this term is a general term for visible light, ultraviolet light, EUV light, X-rays, electron beams, charged particle beams, etc.) as a projection system. This term is a general term for a refractive lens, a reflective lens, a catadioptric lens system, a charged particle lens, etc.), thereby forming a desired pattern on a substrate mounted on the wafer stage 504. . Further, such an exposure apparatus is required to be exposed in a vacuum atmosphere as the exposure light becomes short wavelength light.

  A wafer (object) as a substrate is held on a chuck mounted on a wafer stage 504, and a reticle pattern, which is an original plate mounted on the reticle stage 502, is stepped and repeated in each region on the wafer by an illumination system unit 501. Alternatively, transfer by step and scan. Here, the stage apparatus of the first embodiment is used as the wafer stage 504 or the reticle stage 502.

  Next, a semiconductor device manufacturing process using this exposure apparatus will be described. FIG. 4 is a flowchart showing the overall manufacturing process of the semiconductor device. In step 1 (circuit design), a semiconductor device circuit is designed. In step 2 (mask fabrication), a mask is fabricated based on the designed circuit pattern.

  On the other hand, in step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by using the above-described exposure apparatus and lithography technology using the above-described mask and wafer. The next step 5 (assembly) is called a post-process, and is a process for forming a semiconductor chip using the wafer produced in step 5, and is an assembly process (dicing, bonding), packaging process (chip encapsulation), etc. Process. In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test. A semiconductor device is completed through these processes, and is shipped in Step 7.

  The wafer process in step 4 includes the following steps. An oxidation step for oxidizing the surface of the wafer, a CVD step for forming an insulating film on the wafer surface, an electrode formation step for forming electrodes on the wafer by vapor deposition, an ion implantation step for implanting ions on the wafer, and applying a photosensitive agent to the wafer A resist processing step, an exposure step for transferring the circuit pattern to the wafer after the resist processing step by the above exposure apparatus, a development step for developing the wafer exposed in the exposure step, and an etching step for scraping off portions other than the resist image developed in the development step A resist stripping step that removes the resist that has become unnecessary after etching. By repeating these steps, multiple circuit patterns are formed on the wafer.

1 is a schematic configuration diagram of a stage apparatus according to a first embodiment. Graph showing Paschen's law Diagram showing exposure equipment Diagram showing the semiconductor manufacturing process Diagram showing a conventional vacuum stage device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Stage top plate 2 Guide 3 Coil support member 4 Linear motor coil 5,22 Movable magnet 6 Static pressure bearing 7a Laser length measuring device 7b Mirror 8 Motor coil wire 9 Terminal block 10 Power line 11 Sensor 12 Sensor cable 13 Connector 14 Signal line DESCRIPTION OF SYMBOLS 15 Printed circuit board 16 Amplifying element 17 Weaving cable 18 Feed through connector 19 Vacuum chamber 20 Metal sheet 21 Fixing member 22 Vacuum degree measurement means 23 Position control means 24 Power supply means 501 Illumination system unit 502 Reticle stage 503 Projection lens 504 Wafer stage 505 Exposure apparatus Body

Claims (6)

  In an in-vacuum electric operating device that operates an electrical load in a vacuum chamber, the apparatus has a vacuum degree measuring means for measuring a vacuum degree in the vacuum chamber, and the vacuum degree is measured according to the vacuum degree measured by the vacuum degree measuring means. An in-vacuum electric operating device characterized by changing an operating state of an electric load.   The in-vacuum electric operating device according to claim 1, wherein the electric load is a motor.   The in-vacuum electricity according to claim 1 or 2, wherein a moving stage device is provided in the vacuum chamber, and the stage is decelerated or stopped when the degree of vacuum becomes a predetermined value or less. Operating equipment.   The in-vacuum electric operation according to any one of claims 1 to 3, wherein the stage device has a hydrostatic bearing having a gas recovery mechanism, and nitrogen or helium is used as a gas of the hydrostatic bearing. apparatus.   The in-vacuum electric operation apparatus according to any one of claims 1 to 4, wherein the in-vacuum electric operation apparatus is an exposure apparatus. A device manufacturing method, wherein a device is manufactured using the exposure apparatus according to claim 5.

Images