1. Field of the Invention
The present invention relates to a positioning device and a method of initializing a positioning device, preferably, to be used for semiconductor exposure devices, various kinds of machine tools, various kinds of precision measuring devices, and the like.
2. Description of the Related Art
As shown in
The X beam 2 and the Y beam 4 are provided at each of their both ends with a coarse linear motor moving part using permanent magnets.
Positions of the X beam 2 and the Y beam 4 in their moving directions are measured by means of laser interferometers 83 and 84. The X beam 2 and the Y beam 4 are provided with corner cube reflecting surfaces (not shown), which reflect laser beams or radiation beams X1, X2, Y1 and Y2 irradiated from the laser interferometers 83 and 84. The X beam 2 and the Y beam 4 are positioned by driving and controlling the coarse linear motors on the basis of the values measured by the respective laser interferometers 83 and 84.
The XY slider 13 (
Provided on the upper plate 15 (
The fine movement stage 16 is provided with a mirror having a reflecting surface (not shown). Positions (displacement) of the fine movement stage 16 having six freedoms of movement can be measured by reflecting a laser beam or a radiation beam at the reflecting surface of the stage 16 from a laser interferometer (not shown). The fine movement stage 16 is positioned by driving and controlling the fine linear motor on the basis of values measured by the respective laser interferometers.
In a case in which positions of an object are measured by the use of the laser interferometers, as described above, there is a need to initialize (to calibrate) positional data of the laser interferometers. This is because the interferometer measures relative positions of an object, but not absolute positions.
In general, the initialization may be carried out when turning on a power source. In a commonly-used method for initializing positional data, an object is moved to a reference position, whereupon the measured value is changed to a desired value. In this case, for example, a mechanical abutment or a shading switch may be used as a reference position.
In an initialization sequence, it is required to move an object to the reference position. The coarse linear motors may be operated in a system that selects polyphase coils to be energized. Methods for selecting coils to be energized are disclosed in Japanese Patent Application Laid-Open Nos. 64,487/1993 and 316,607/1999.
In order to move an object to a reference position, moreover, the object must be guided. In a case in which the XY slider 13, the X beam 2 and the Y beam 4 are guided with the aid of gas bearings, as described above, the guiding function can be given to the gas bearings by supplying gas to them when turning on the power source. In a case in which the XY slider 13, the X beam 2 and the Y beam 4 are guided by the use of electromagnetic guidance, however, there is no guiding function when turning on the power source.
In view of the problems described above, an object of the present invention is to provide an improved arrangement and a sequence for initializing a relative position sensor in a positioning device having electro-magnetic guides.
In order to achieve the above object, the positioning device according to the invention comprises an object movable at least in directions X and Y, object position measuring means for measuring positions of the object, a first auxiliary structure guiding the object in the direction Y and movable in the direction X, a second auxiliary structure guiding the object in the direction X and movable in the direction Y, at least two pairs of electromagnet units provided on the object in such a manner as to embrace side faces of the first auxiliary structure and the second auxiliary structure, and a rotation regulating portion for regulating the rotation of at least one of the first and second auxiliary structures.
In this case, the positioning device preferably has magnetic members provided on side faces of the first and second auxiliary structures to produce attracting forces between the magnetic members and the electromagnet units. Moreover, the positioning device according to the invention may comprise first position measuring means for measuring positions of the first auxiliary structure in the direction X and second position measuring means for measuring positions of the second auxiliary structure in the direction Y.
In another aspect of the invention, a method of initializing a positioning device electro-magnetically guiding an object along two orthogonal beams comprises a step of regulating rotation of one of the beams and a step of causing the beam regulated in rotation and the object to be electro-magnetically attracted.
The method of initializing a positioning device according to the invention preferably comprises at least one of a step of offsetting a position measuring device for measuring a position of the object when the object is attracted, a step of attracting the other beam to the object under a condition maintaining the object and the one beam in a predetermined relative positional relationship, and a step of moving the other beam to a predetermined reference position under a condition maintaining the object and the one beam in a predetermined relative positional relationship.
Moreover, an exposure device according to the invention may be an exposure device comprising any of the positioning devices described above, or an exposure device for positioning at least one of a substrate and a negative plate by means of a stage using any of the initializing methods described above. Further, the invention is also applicable to a method of producing a device comprising a step of producing the device by the use of any of the exposure devices described above.
Further features and advantages of the present invention will become apparent from the following description of exemplary embodiments (with reference to the attached drawings).
The wafer stage 200 includes a stage surface plate 1, an X beam 2, a Y beam 4 and an XY slider (not shown—see element 13 in
The electromagnets 20 are used as electromagnet units of two opposed electromagnets in order to produce the attraction only. As shown in
A controller produces control commands for the respective electromagnet units on the basis of command values for the XY slider and measured values of positions of the XY slider. Positioning of the XY slider can be carried out based on the produced control commands from the controller.
As shown in
Initializing sequences will be explained with reference to FIGS. 4 to 8 hereinafter.
Generally speaking, in contrast with a wafer stage provided with gas bearings between the XY slider and the X and Y beams 2 and 4, in a wafer stage provided with an electro-magnetic guide, the XY slider 13 does not have the guiding function when the power source is turned on, so that it is impossible to drive the stage to be initialized. In the present invention, accordingly, initializing sequences for initializing the stage including initialization of the electromagnetic guide will be proposed.
(Step 1) As shown in
(Step 2) As shown in
(Step 3) As to initialization of the measured values of the positions in the direction Y, the method disclosed in Japanese Patent Application Laid-Open No. 316,607/1999 may be used. In more detail, as shown in
(Step 4) As shown in
(Step 5) As to initialization of the measured values of the positions in the direction X, a method disclosed in Japanese Patent Application Laid-Open No. 316,607/1999 may be used. In more detail, as shown in
By carrying out Steps 1 to 5 described above, the initialization of the laser interferometer is completed in the direction X of the X beam 2 (i.e., rotation in the direction θz is regulated by the rotation regulating portion 3), in the directions Y and Oz of the Y beam 4, and in the directions X, Y and θz of the XY slider 13. In order to judge whether the X beam 2, the Y beam 4 and the XY slider 13 have arrived at the respective reference position, reference position judging means 36 and 37 may be used. As means for judging the reference position, various means may be effected such as, for example, (a) providing a shade on the beam and providing a photo-interrupter at the reference position, (b) providing a mechanical switch, such as a lever switch at the reference position, and (c) providing an abutment stopper adapted to abut against the reference position.
In Step 1, moreover, after the XY slider 13 has been attracted to the X beam 2, the XY slider 13 may be attracted to the Y beam 4, as well. The Y beam 4 is landed and after the initialization in the direction X has been carried out according to Steps 4 and 5, the initialization in the direction Y may be effected according to Steps 2 and 3. In this case, the Y beam 4 is landed, instead of a position servo being applied to the Y beam 4 in Step 4. And in Step 2, a position servo is applied to the X beam 2, instead of the X beam 2 being landed, and Step 3 is carried out.
The initializing sequences in the second embodiment will be explained with reference to FIGS. 10 to 14, hereinafter.
(Step 1) As shown in
(Step 2) As shown in
(Step 3) As to the initialization of the measured values of the positions in the direction Y, the method disclosed in Japanese Patent Application Laid-Open No. 316,607/1999 may be used. In more detail, as shown in
(Step 4) As shown in
(Step 5) As to the initialization of the measured values of the positions in the direction X, the method disclosed in Japanese Patent Application Laid-Open No. 316,607/1999 may be used. In more detail, as shown in
According to Steps 1 to 5, the initialization of the laser interferometer is completed in the direction X of the X beam 2 (the rotation in the direction θz is regulated by the rotation regulating portion 3), in the direction Y of the Y beam 4 (the rotation in the direction θz is regulated by the rotation regulating portion 5), in the directions X, Y and θz of the XY slider 13. In order to judge whether the X beam 2, the Y beam 4 and the XY slider 13 have arrived at the reference position, reference position judging means 36 and 37 may be used. As means for judging the reference position, various means may be effected such as, for example, (a) providing a shade on the beam and providing a photo-interrupter at the reference position, (b) providing a mechanical switch, such as a lever switch at the reference position, and (c) providing an abutment stopper adapted to abut against the reference position.
Moreover, Steps 2 and 3 may be performed after the initialization in the direction X in Steps 4 and 5 has been performed. In such a case, in Step 4, the Y beam 4 is landed and the initialization is performed in advance, instead of a position servo being applied to the Y beam 4. Then, in Step 2, a position servo is applied to the X beam 2 in the direction X, instead of the landing of the X beam 2, and Step 3 is performed.
The electromagnets for the attraction are not limited to the electromagnets illustrated in the drawings of the embodiments, and, for the attraction, a plurality of electromagnets or all the electromagnets may be used. The electromagnets for carrying out the position servo are not limited to the two sets of electromagnets illustrated in the drawings of the embodiments, and any combination of electromagnets or all the electromagnets may be used.
In performing the attraction by the electro-magnetic guide of the XY slider 13, moreover, as shown in
This exposure device is utilized in producing semiconductor devices for semiconductor integrated circuits, and devices formed with fine patterns, such as micro machines, microfilm magnetic heads, and the like. Desired patterns are formed on a substrate by irradiating an exposure light as exposure energy from a light source 61 through a reticle R, as a negative plate, and through a projection lens, as a projection system, onto a semiconductor wafer W as a substrate. The term “exposure light” is a general term for visible light, ultra violet light, EUV, X-rays, electron beams, charged particle beams, and the like. The term “projection lens” is a general term for a dioptric lens, a reflecting lens, a reflecting dioptric lens system, a charged particle lens, and the like.
In the exposure device, a guide 52 and a linear motor stationary part 72 of each of the linear motors are fixedly provided on a surface plate 51. The linear motor stationary part 72 has polyphase electromagnetic coils and the linear motor moving part 71 of each of the linear motors has permanent magnets. Each of the linear motor moving parts 71, as a movable portion 53, is connected to a movable guide 54, as a stage, so that the linear motors Ml are energized to move the movable guides 54 in the direction of the normal line of the drawing. The movable portion 53 is supported by gas bearings 55 along the upper surface of the surface plate 51 as a reference, and is also supported by gas bearings 56 along the side surface of the guide 52 as a further reference.
Supported by gas bearings 58 is a movable (wafer) stage 57, which is a stage arranged to bridge between the movable guides 54 and be supported by gas bearings 58. The movable stage 57 is driven by linear motors M2, similar to the linear motors described above, and moved along the movable guide 54 as a reference in the right and left direction viewed in the drawing. The movement of the movable stage 57 is measured by the use of a mirror 59 fixed to the movable stage 57 and an interferometer 60.
A wafer W, as a substrate, is held in chucks mounted on the movable stage 57. Patterns of a reticle R, as a negative plate, are transcribed in a reduced scale in respective regions on the wafer W in a step-and-repeat or a step-and-scan process.
Moreover, the positioning device according to the present invention is also applicable to an exposure device of a type in which circuit patterns are directly transcribed on a semiconductor wafer by exposing a resist without using a mask.
Processes for producing semiconductor devices utilizing this exposure device will be explained hereafter.
In Step 3 (produce wafer), on the other hand, the wafer is made using a material, such as silicon, and the like. In Step 4 (wafer process), which is called preprocessing, an actual circuit is formed on the wafer using the above mask and wafer utilizing lithography with the above exposure device. In the next step, Step 5 (assembling), which is called post-processing, the wafer made in Step 4 is processed into semiconductor chips, including assembling (dicing and bonding), packaging (enclose chips), and other assembling steps. In Step 6 (inspection), the semiconductor devices produced in Step 5 are inspected to ascertain their operation and to test their durability and other attributes. The semiconductor devices are completed through these steps and shipped to destinations, in Step 7.
The wafer process of the above Step 4 includes an oxidizing step for oxidizing wafer surfaces, a chemical-vapor-deposition (CVD) step for forming insulating films on the wafer surfaces, an electrode forming step for forming electrodes on the wafer by vapor deposition, an ion driving step for driving ions into the wafer, a resist treating step for coating a photosensitive agent on the wafer, an exposure step for transcribing the circuit patterns on the wafer already subjected to the resist treating step by means of the above exposure device, a developing step for developing the wafer exposed in the exposure step, an etching step for removing portions except for the resist images developed in the exposure step, and a resist peeling step for removing the resist which has become unnecessary when the etching step has been completed. By performing these steps repeatedly, circuit patterns can be formed on the wafer in a multiple manner.
Except as otherwise discussed herein, the various components shown in outline or in block form in the Figures are individually well known and their internal construction and operation are not critical either to the making or using or to a description of the best mode of the invention.
While the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments. On the contrary, the invention is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.
This application claims priority from Japanese Patent Application No.#2004-089502 filed Mar. 25, 2004, which is hereby incorporated by reference herein.
Number | Date | Country | Kind |
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2004-089502 | Mar 2004 | JP | national |