JP2006229122A - Method for removing foreign material on surface of chuck, vessel and table - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for removing foreign materials stuck on the surface of a chuck while a vacuum state is maintained. <P>SOLUTION: As shown in Fig.(a), a vessel 7 for purge is mounted on a lifting table 5 instead of a reticle by a carrier robot not shown in the figure. Then, as shown in Fig.(b), the lifting table 5 is raised in a state that a reticle stage 1 has come to a chucking position to the position where a purge port 7a of the vessel 7 for purge is apart from the surface of an electrostatic chuck 2 by several millimeters. In this state, gas is blown off from the purge port 7a to gas-purge the surface of the electrostatic chuck 2, and the particles stuck on the surface of the electrostatic chuck 2 are blown off. The blown-off particles and the gas for purge are discharged to the outside of an exposure device by a vacuum pump vacuuming the exposure device. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a method for removing foreign matter adhering to the surface of a chuck used for attracting and holding a reticle or wafer used in an exposure apparatus, and a container and a table used in this method.

  As the degree of integration required for semiconductor devices increases, the precision of exposure apparatuses used in lithography processes during the manufacturing process is required. Recently, electron beam exposure apparatuses (EPL) and extreme ultraviolet exposure apparatuses are required. (EUVL) is being used.

  In EPL and EUVL, since a reticle and wafer are used in a high vacuum, an electrostatic chuck is used as a chuck for holding them.

  However, when an electrostatic chuck is used, due to the residual electric field of the electrostatic chuck, particles (foreign matter) having a charge floating in the space are attracted to the surface of the electrostatic chuck and remain on the surface as they are. appear. When such a situation occurs, the flatness of the wafer and the reticle surface may be distorted while the wafer and the reticle are attracted.

  In particular, in EUVL using a reflective reticle, the reticle surface must be suppressed to a flatness of several nanometers, so that particles of about several tens of nanometers are not allowed to adhere to the electrostatic chuck as well as the reticle surface.

  As a countermeasure, the vacuum state is appropriately broken and manually cleaned in a state where the pressure is returned to the atmospheric pressure, but the process of breaking the vacuum state is increased, and complete cleaning is difficult. On the contrary, there is a problem that the number of particles adhering to the chuck surface is increased.

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a method for removing foreign matter adhering to the chuck surface while maintaining a vacuum state, and a container and a table used in this method. To do.

  A first means for solving the above problems includes a chuck having a suction surface for attracting a substrate facing downward, and placing the substrate so as to face the chuck to perform vertical movement, and moving the substrate to the An apparatus having a table that transports a chuck to a position where chucking is possible, and a method for removing foreign matter adhering to the surface of the chuck, wherein a container containing a purge gas container is used instead of the substrate. A chuck surface foreign matter removing method comprising: placing the container on the surface, driving the table to position the container in the vicinity of the chuck, and blowing a purge gas from the container to the surface of the chuck in that state. It is.

  In this means, the container is placed on the table, the table is raised, and the purge gas ejection portion of the container is brought close to the chuck surface. Then, in this state, purge gas is ejected to purge and remove foreign matter on the chuck surface. When the chuck is in a vacuum, the purge gas is normally discharged by a vacuum pump provided in such an apparatus, so that a gas barge can be performed without breaking the vacuum state.

  The second means for solving the problem includes a chuck having a suction surface for sucking the substrate downward, and placing the substrate so as to face the chuck, and moving the substrate up and down. In an apparatus having a table that conveys the chuck to a position where chucking is possible, a method for removing foreign matter adhering to the surface of the chuck, wherein an adhesive film is placed on the table instead of the substrate, A method for removing foreign matter from a chuck surface, wherein the table is driven to bring the adhesive film into contact with the surface of the chuck, and then the table is driven to separate the adhesive film from the surface of the chuck. .

  In this means, the adhesive film is placed on the table, the table is raised, the adhesive film is brought into contact with the chuck surface, foreign matter existing on the chuck surface is adhered to the adhesive film, and the table is lowered and adhered in that state. By removing the film from the chuck surface, foreign matter on the chuck surface is removed.

  In this means, even when the chuck is placed in a vacuum, foreign matter on the chuck surface can be removed without breaking the vacuum.

  A third means for solving the above problem is a container used for the foreign matter removing method on the chuck surface as the first means, and a container for storing a purge gas, and a container for storing the purge gas. A solenoid valve connected by a pipe and a pipe, and a coil for generating electric power for driving the electromagnetic valve by electromagnetic induction from the outside. When the electric power is generated, the electromagnetic valve is opened, and the purge valve A container characterized in that gas is discharged to the outside.

  According to this means, the timing of releasing the purge gas from the outside can be controlled without performing external wiring.

  The third means for solving the problem is to place the substrate so as to face a chuck having an adsorption surface for adsorbing the substrate facing downward, and to move the substrate up and down. It is a table which conveys to the position which can perform, Comprising: It is a table characterized by having a coil which can supply electric power to the said coil of the container which is said 3rd means by electromagnetic induction.

  According to this means, it is possible to supply electric power necessary for driving the electromagnetic valve in a non-contact manner to the coil of the container.

  ADVANTAGE OF THE INVENTION According to this invention, the method of removing the foreign material adhering to the chuck | zipper surface, maintaining a vacuum state, the container used for this method, and a table can be provided.

  Hereinafter, an example of an embodiment of the present invention will be described. Prior to that, an example of an apparatus relating to an electrostatic chuck of a reticle stage of an exposure apparatus will be described with reference to FIG. To do. An electrostatic chuck 2 is attached to the reticle stage 1 so that the chuck surface faces downward. The reticle stage 1 is moved in the direction of the left and right arrows in the figure by the reticle stage drive mechanism 3. That is, the reticle 4 is chucked at the position shown in FIG. 1 and conveyed to an exposure position (not shown) on the right side of the drawing.

  A lifting table 5 is provided at the chucking position shown in the drawing, and is moved up and down as indicated by arrows in the drawing by the driving device 6. The reticle 4 is transported by a transport robot (not shown) and placed on the lift table 5 with the lift table 5 in the lowered position. In this state, the reticle stage 1 is moved to the left as shown in FIG. 1, and the elevating table 5 is raised to raise the reticle 4 to a position where the electrostatic force of the electrostatic chuck 2 works. The drive device 6 is provided with a position detection mechanism (not shown), whereby the distance between the reticle 4 and the lower surface of the electrostatic chuck 2 can be known. In a state where the reticle 4 is lifted up to a position where the electrostatic force of the electrostatic chuck 2 is applied, a voltage is applied to the electrostatic chuck 2, the reticle 4 is chucked and fixed, and the exposure position (not shown) on the right side of the figure is reached. Transport.

  When the use of the reticle 4 is finished, the lift table 5 is raised so that the surface of the lift table 5 is slightly below the lower surface of the reticle 4 held by the electrostatic chuck 2 of the reticle stage 1, and the reticle stage 1 is moved to the position shown in FIG. 1, the voltage of the electrostatic chuck 2 is turned off, the reticle 4 is placed on the lifting table 5, the lifting table 5 is then lowered, and the reticle 4 is moved by a transfer robot (not shown). Take it out.

  Hereinafter, an example of an embodiment of the present invention will be described with reference to the drawings. In the following drawings, the same components as those shown in the previous drawings are denoted by the same reference numerals and the description thereof will be given. May be omitted. FIG. 2 is a diagram for explaining the foreign matter removing method for the chuck surface according to the first embodiment of the present invention.

  First, as shown in FIG. 2A, the purge container 7 is placed on the lifting table 5 instead of the reticle by a transfer robot (not shown). Then, as shown in FIG. 2 (b), with the reticle stage 1 in the chucking position, the elevating table 5 is raised, and the purge port 7 a of the purge container 7 is several times from the surface of the electrostatic chuck 2. In this state, gas is blown out from the purge port 7a, the surface of the electrostatic chuck 2 is purged with gas, and particles adhering to the surface of the electrostatic chuck 2 are blown off. The blown particles and the purge gas are discharged out of the exposure apparatus by a vacuum pump that evacuates the exposure apparatus.

  FIG. 3 shows an example of a more detailed structure of the purge container 7. A purge gas storage container 8, a solenoid valve 9, and a coil 11 for supplying power to the solenoid valve 9 are housed in the purge container 7. The piping from the purge gas storage container 8 is connected to the nozzle 10 of the purge port 7 a through the electromagnetic valve 9. On the other hand, the lifting table 5 is provided with a coil 12 for supplying power. When the coil 12 is excited, the coil 11 generates an electromotive force due to electromagnetic coupling between the coil 12 and the coil 11, thereby driving the electromagnetic valve 9 to open, and the gas in the purge gas storage container 8 is transferred to the nozzle 10. It is supplied and purged. By using the purge container 7 and the lifting table 5 having such a structure, the surface of the electrostatic chuck 2 described with reference to FIG. 2 can be purged with gas.

  FIG. 4 is a diagram for explaining a foreign matter removing method for a chuck surface according to a second embodiment of the present invention. In this case, as shown in FIG. 3A, the block 14 having the adhesive film 13 attached to the surface is placed on the lifting table 5 by a transport robot (not shown). Then, as shown in FIG. 3B, with the reticle stage 1 in the chucking position, the lifting table 5 is raised and the adhesive film 13 is brought into contact with the surface of the electrostatic chuck 2.

  In order to prevent an excessive force from being applied between the adhesive film 13 and the electrostatic chuck 2 at the time of contact, the adhesive film 13 is made thick to some extent to be elastic or between the adhesive film 13 and the block 14. It is preferable to sandwich an elastic material between the two. Due to the position detector provided in the driving device 6, the lifting table 5 is raised too much and an excessive force acts between the adhesive film 13 and the electrostatic chuck 2, or the adhesive film 13 and the electrostatic chuck 2 come into contact with each other. Control so that there is no or nothing.

  When the electrostatic chuck 2 and the adhesive film 13 come into contact, particles adhering to the surface of the electrostatic chuck 2 adhere to the adhesive film 13. When the elevating table 5 is lowered in this state, the particles are removed from the surface of the electrostatic chuck 2 while being adhered to the adhesive film 13. The surface of the electrostatic chuck 2 also adheres to the adhesive film 13, but the weight of the block 14 is sufficiently increased so that the adhesive film 13 and the electrostatic chuck 2 are separated by gravity when the lifting table 5 is lowered. In this way, particles adhering to the surface of the electrostatic chuck 2 can be removed.

It is a figure which shows the example of the apparatus regarding the electrostatic chuck of the reticle stage of exposure apparatus. It is a figure for demonstrating the foreign material removal method of the chuck | zipper surface which is the 1st Embodiment of this invention. It is a figure which shows the example of the more detailed structure of the container for purges. It is a figure for demonstrating the foreign material removal method of the chuck | zipper surface which is the 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Reticle stage, 2 ... Electrostatic chuck, 3 ... Reticle stage drive mechanism, 4 ... Reticle, 5 ... Lifting table, 6 ... Drive apparatus, 7 ... Purge container, 7a ... Purge port, 8 ... Purge gas storage container , 9 ... Solenoid valve, 10 ... Nozzle, 11 ... Coil, 12 ... Coil, 13 ... Adhesive film, 14 ... Block

Claims (4)

A chuck provided with a suction surface facing down the substrate, and a table that moves the substrate up and down so as to face the chuck and transports the substrate to a position where chucking of the chuck is possible; In the apparatus having the above, a method for removing foreign matter adhering to the surface of the chuck, wherein a container containing a purge gas container is placed on the table instead of the substrate, and the table is driven to drive the table. A method for removing foreign matter on a chuck surface, wherein a container is positioned in the vicinity of the chuck, and in that state, a purge gas is blown from the container onto the surface of the chuck. A chuck provided with a suction surface facing down the substrate, and a table that moves the substrate up and down so as to face the chuck and transports the substrate to a position where chucking of the chuck is possible; The apparatus has a method for removing foreign matter adhering to the surface of the chuck, placing an adhesive film on the table instead of the substrate, and driving the table to attach the adhesive film to the chuck. A method for removing foreign matter from a chuck surface, wherein the method is configured to contact the surface and then drive the table to separate the adhesive film from the surface of the chuck. It is a container used for the foreign matter removal method of the chuck | zipper surface of Claim 1, Comprising: The container which accommodates the gas for purge, The electromagnetic valve connected with the container which accommodates the said gas for purge, and piping from the outside, A coil for generating electric power for driving the electromagnetic valve by electromagnetic induction, and when the electric power is generated, the electromagnetic valve is opened, and the purge gas is discharged to the outside. Characteristic container. A table for moving the substrate to a position where chucking of the chuck can be performed by placing the substrate so as to face a chuck provided with a suction surface for sucking the substrate facing downward. A table having a coil capable of supplying power by electromagnetic induction to the coil of the container according to Item 3.

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