JP6536777B2 - Control system and control method, exposure apparatus and exposure method, and device manufacturing method - Google Patents

Description

  The present invention relates to a control system and control method, an exposure apparatus and method, and a device manufacturing method, and more particularly, to a control system and control method for driving and controlling a control object by giving a control input (operation amount). The present invention relates to an exposure apparatus including the exposure apparatus, an exposure method using the control method, and a device manufacturing method using the exposure method.

  In lithography processes for manufacturing electronic devices (microdevices) such as liquid crystal display elements and semiconductor elements, mainly, a step-and-repeat type projection exposure apparatus (so-called stepper), a step-and-scan type projection exposure apparatus (so-called stepper) A scanning stepper (also called a scanner) or the like is used. With respect to exposure devices for liquid crystal display elements (liquid crystal exposure devices), scanning type projection exposure devices such as scanners have become mainstream as substrates become larger. Electronic devices (microdevices) are manufactured by forming a plurality of layers of patterns on a substrate (glass plate, wafer, etc.). For this reason, the exposure apparatus is required to accurately and rapidly overlap and transfer the mask pattern on the pattern previously formed on the substrate, that is, high overlay accuracy and high throughput.

  A coarse and fine movement type substrate stage configured of a coarse movement stage driven on the base by a relatively large driving force and a fine movement stage supported by the coarse movement stage and precisely driven thereon, the substrate In order to drive the fine movement stage to be held at high speed, a catapult-type drive device has been developed in which the coarse movement stage is brought into contact with the fine movement stage and the driving force of the coarse movement stage is applied to the fine movement stage. . However, chattering (mechanical vibration) occurs when the coarse movement stage abuts on the fine movement stage, which hinders precise driving of the substrate stage (fine movement stage) and lowers the overlay accuracy, and also breaks the substrate stage. There is also a risk of

  With respect to an open system control system in which the driven object (fine movement stage) contacts the outside (coarse movement stage) beyond the boundary like the substrate stage of the above configuration, when the driven object contacts the outside Chattering can be suppressed by controlling the viscosity and elasticity (hereinafter referred to as visco-elastic characteristics) between them. The representative approaches are roughly classified into a control approach and a mechanical approach.

  As an example of a control approach, impedance control is known which adjusts visco-elastic characteristics (which may further include inertia) between the driven object and the outside. In impedance control, first, an input (disturbance) that acts on the drive target from the outside is obtained using a force sensor or the like. Next, a position command is determined from the external force so that the viscoelastic characteristic obtained by feeding back the command is adjusted to a desired characteristic. Finally, the position command is fed back to drive and control the drive target (control the position of the drive target). Since the accuracy of the drive control depends on the accuracy of the response of the control object to the position command, the impedance control is not necessarily suitable for a fast response external force such as a force due to a collision.

  On the other hand, as an example of a mechanical approach, a method using an electro-rheological fluid (ER fluid) whose viscosity is changed by applying a voltage, that is, an ER fluid is interposed between an object to be driven and the outside, There is a way to control. However, in an exposure apparatus that requires high drive accuracy (positioning accuracy) to be driven, the presence of an ER fluid may be a non-linear factor in feedback control. Therefore, it is usual to eliminate the viscosity acting on the drive target by adopting an air guide or the like. Furthermore, the change in viscosity due to the aging of the ER fluid also becomes a problem.

  Therefore, it is promising to use feedback control to virtually adjust the visco-elastic characteristics of the object to be driven against the external force with a quick response by utilizing the high responsiveness of the drive device mounted on the exposure apparatus or the like.

Unexamined-Japanese-Patent No. 2003-45785

According to a first aspect of the present invention, there is provided a control system that generates an operation amount of the control object from the control target amount of the control object, the input unit to which the control amount is input, the control amount or A first amount determined from a generation amount generated by calculation using the controlled amount and a first model corresponding to the control target, and a second model different from the generation amount and the first model And a control unit that generates the operation amount using a difference from the second amount to be obtained, and the second model is a table in which a disturbance applied to the control target and the controlled amount are a predetermined function. The control unit has a disturbance observer including the second model, and the disturbance observer inputs a third amount obtained from the first amount and the operation amount and the controlled amount. control systems that outputs a correction amount for correcting the manipulated variable is provided It is.

  According to this, it becomes possible to drive the control object precisely and stably.

  According to a second aspect of the present invention, there is provided an exposure apparatus for exposing an object with an energy beam to form a pattern on the object, wherein the first moving body holds and moves the object; A moving mechanism having a second moving body movable relative to the first moving body while supporting the moving body, and a control system according to a first aspect in which the first moving body is the control target. An exposure apparatus comprising:

  According to this, it is possible to drive the moving object holding the object precisely and stably, and in turn, it is possible to perform high-precision exposure on the object.

According to a third aspect of the present invention, there is provided a control method for controlling a control target that receives an operation amount and outputs a controlled amount, and obtaining information related to the position of the control target as the controlled amount. And determining a first amount to be input to the controlled object from the controlled amount or a generation amount generated by calculation using the controlled amount, and a first model corresponding to the controlled object. Determining the second amount input to the control target from the generation amount and the second model different from the first model, and using the first amount and the second amount to perform the operation Generating a quantity , wherein the second model is a disturbance observer including the second model in which the disturbance applied to the controlled object and the controlled quantity are represented by a predetermined function; Is obtained from the first amount and the operation amount by 3 amount and the enter the controlled quantity, controlling how to output a correction amount for correcting the manipulated variable is provided.

  According to this, it becomes possible to drive the control object precisely and stably.

According to a fourth aspect of the present invention, there is provided an exposure method for exposing an object with an energy beam to form a pattern on the object, comprising: a first moving body for holding and moving the object; A control method according to a third aspect, wherein the first movable body is the control target in a moving mechanism having a second movable body movable with respect to the first movable body while supporting the movable body. An exposure method to be used is provided.

  According to this, it is possible to drive the moving object holding the object precisely and stably, and in turn, it is possible to perform high-precision exposure on the object.

  According to a fifth aspect of the present invention, there is provided a method of forming a pattern on an object using the exposure method according to the fourth aspect, and developing the object on which the pattern is formed. A device manufacturing method is provided.

It is a block diagram showing basic composition of a feedback control system concerning a 1st embodiment. It is a block diagram which shows the deformation | transformation structure of the feedback control system which concerns on 1st Embodiment. FIGS. 3A to 3C are diagrams (Nos. 1 to 3) for explaining derivation of a modified configuration from the basic configuration of the feedback control system. FIGS. 4A and 4B are diagrams (4 and 5) for explaining derivation of a modified configuration from the basic configuration of the feedback control system. It is a Bode diagram showing the frequency response characteristic of a plant. It is the table | surface which put together the physical parameter employ | adopted in the disturbance observer which comprises a feedback control system. It is a figure which shows the simulation result of the time response characteristic of a plant. It is a block diagram showing composition of a feedback control system concerning a 2nd embodiment. It is a table | surface which put together the physical parameter employ | adopted in simulation. It is a Bode diagram showing the frequency response characteristic of a amendment part. It is a Bode diagram showing the frequency response characteristic of a plant. It is a figure which shows the sensitivity characteristic of a control system. It is a block diagram which shows another structure of the feedback control system which concerns on 2nd Embodiment. It is a figure which shows roughly the structure of the exposure apparatus which concerns on 3rd Embodiment. FIG. 7 is a block diagram showing a configuration related to stage control of the exposure apparatus. It is a figure which shows a structure and arrangement | positioning of a mask stage, a mask stage drive system, and a mask interferometer system. It is a figure which shows the structure of a gas flow apparatus. FIGS. 18A and 18B are block diagrams for describing control switching in a feedback control system of a fine movement stage constituting a catapult type stage device. FIGS. 19A and 19B are diagrams showing a reaction force and a position error received by the fine movement stage when the coarse movement stage collides with the fine movement stage while accelerating, respectively.

First Embodiment
Hereinafter, a first embodiment will be described using FIGS. 1 to 7.

FIG. 1 shows a basic configuration of a control system 50 according to the first embodiment. The control system 50 is a feedback control system for controlling driving of the control target 52 by providing a control input U, the sensor 52 ₂ for measuring the position y of the control object 52 as the controlled amount, the output of the sensor 52 ₂ ( and a controller 54 that the measurement result) of the position y performs an operation gain-multiplied (-1 times) to obtain the correction amount from the output of the controller 54 (i.e., the output of the sensor 52 _2), controlled as a result the control input U a correction unit 53 for transmitting the drive unit 52 ₁ for driving the target 52, and a. The value of the gain multiple in the controller 54 is not limited to that of this embodiment, and can be set to an arbitrary value.

Drive device 52 ₁ in accordance with the received control input U (having a dimension of the force in the present embodiment), emits equal driving force to the drive quantity. Thus, the drive target is drive-controlled. In FIG. 1, the driving device 52 ₁ and the sensor 52 ₂ is shown as being included in the control object 52. Further, d shown in the figure is a disturbance that acts on the control target 52 from the outside, and is unknown. The control input U and the position y are respectively an input and an output for the control target 52, both of which are known. The actual input to the controlled object 52 is a control input U which is output from the correction unit 53 (equivalent to the driving force driving apparatus 52 ₁ emitted) to the sum of the disturbance d.

  Here, although the controlled variable, the control input and the like are defined as a function of time, in the explanation using FIG. 1 and the like, it is assumed that their Laplace transform is used according to the custom.

As the sensor 52 _2, interferometer, adopting a position sensor such as an encoder. Sensor 52 ₂ is always measured position y of the control object 52, and outputs the result to the correction unit 53. Sensor 52 ₂ is not intended to be limited to the interferometer or an encoder, it may use other measuring devices.

The controller 54 is actually realized by a microcomputer and software, but may of course be configured by hardware. The control unit 54 has been inserted between the sensor 52 ₂ and the correcting unit 53, instead of this, may be inserted between, for example, the correction unit 53 and the controlled object 52. In this case, the controller 54 multiplies the output of the correction unit 53 by a gain (-1) and outputs the result to the control target 52 (drive device 52 ₁ ).

The correction unit 53 includes two controllers 53a and 53b and a subtractor 53c. Note that each of these components is actually realized by a microcomputer and software as in the controller 54, but may of course be configured by hardware. The controller 53a is a transfer given by the product of the filter Q representing the phase delay and the inverse of the transfer function Pn corresponding to the nominal model representing the control object 52 (the model reproducing the actual response of the control object 52). It has a characteristic. The controller 53a receives an amount to be controlled y (strictly speaking, an amount -y through the controller 54), and thereby the amount actually input to the control object 52 (referred to as a first amount) Ask. The result is output to the subtractor 53c. The controller 53b has a transfer characteristic given by the product of the filter Q and the inverse of the transfer function _Gimp corresponding to a model (a model expressing a desired response) exhibiting a desired behavior (impedance characteristic described later). The controller 53 b obtains an amount (referred to as a second amount) to be input to the control target 52 by receiving the controlled amount y (strictly speaking, the amount −y via the controller 54). The result is output to the subtractor 53c. The subtractor 53c calculates the difference (second amount-first amount) of the outputs (first and second amounts) of the controllers 53a and 53b, and the result is the control object 52 (drive device 52 ₁ ) Output toward

In the control system 50 configured as described above, the sensitivity function S = 1 / (1 + PC ₅₃ ) is given, and the transfer function of the correction unit 53 is C ₅₃ = Q (G _imp ⁻¹ −P n ⁻¹ ). Under the ideal condition, that is, the response characteristic P of the control target 52 is equal to the nominal model (the transfer function corresponding to it) Pn, and assuming the ideal filter Q = 1, the sensitivity function S = P ⁻¹ G _imp is derived. From the response characteristic of the control object (the characteristic from the external force d to the output y) Pd = y / d = SP, Pdn = _Gimp is derived under ideal conditions. This means that the response characteristic (the relationship between the disturbance d and the controlled amount y) of the controlled object with respect to the disturbance d can be changed to the desired characteristic (desired relationship) represented by the transfer function G _imp .

  In a modified configuration equivalent to the basic configuration of the control system 50 described above, the performance of the control system 50 according to the first embodiment is evaluated. In addition, while using the same code | symbol to the component same as the basic composition of the control system 50, detailed description is also abbreviate | omitted.

FIG. 2 shows a modified configuration (control system 50 ′) of the control system 50 according to the first embodiment. The control system 50 'is a feedback control system that drives and controls the control target 52 by giving the control input U, as in the basic configuration described above, and the drive target of the control target 52 (having a dimension of the driving force) generates R, the result calculates the control input U using (and correction amount dU described later), the result, the stage controller 51 to be transmitted to the drive unit 52 ₁ for driving the controlled object 52, a controlled a sensor 52 ₂ for measuring the position y of the control object 52 is an amount comprised of, a correction unit 53 'for determining the correction amount dU with respect to the control input U from the output of the sensor 52 ₂ (measurement results of the position y).

Stage controller 51 includes a target generator 51 ₀ and a subtractor 51 _2. In addition, although these components are actually realized by the microcomputer and software that configure the stage control device 51, they may be configured by hardware. Target generator 51 _0, drive target of the controlled object 52 (in this case the target has dimensions of driving force) to generate R, supplied to the subtracter 51 _2. Subtractor 51 _2, the output from the driving target R and the correction section 53 (correction amount) to calculate the difference R-dU and dU seek control input U, toward the control object 52 (driving device 52 ₁₎ Output Do.

Correcting unit 53 'is configured as a disturbance observer in two stages, including a two disturbance observer _53, 53 ₃ and the adder 53 _2. In addition, although these components are actually realized by the microcomputer and software that configure the stage control device 51, they may be configured by hardware. First stage of the disturbance observer 53 _1, the output of the sensor 52 and _second output (the controlled variable) y and stage controller 51 (control input) U and are inputted, estimates a disturbance d applied from outside to the control target 52 Do. Result of Estimation <d> is output to the adder 53 _2. The adder 53 ₂ calculates a sum of the output of the disturbance observer 53 ₁ (estimation of the disturbance d) and Between <d> and the output (the control input) U of the stage controller 51, to output to the disturbance observer 53 _3. Second stage of the disturbance observer 53 _3, the output of the sensor 52 ₂ (the controlled variable) y and the adder 53 ₂ outputs U + <d> is input, calculates a correction amount dU. The result is output to the stage control device 51 (subtractor 51 ₂ ).

  Here, it will be described that the above-described control system (modified configuration) 50 '(correction unit 53' included in the above) is equivalent to the above-described control system (basic configuration) 50 (correction unit 53 included in the above).

A control system (basic configuration) 50 is shown in FIG. However, the relative positions of the correction unit 53 and the controller 54 are interchanged. In the correction unit 53, two controllers 53a, (given by the product _Q 1 _{Q 2} of the two filters) that two filter _Q 1, is divided into _{Q 2} filter Q contained in 53b. Corresponding to this, as shown in FIG. 3 (B), the controller 53a is divided into two controllers 53 ₁₁ and 53 _{32 connected} in series. Here, the controller 53 ₁₁ has a transfer characteristic given by the product of the inverse of the transfer function Pn corresponding to the filter Q _1, nominal model (model to reproduce the actual response of the controlled object 52). The controller 53 _11, by the controlled variable y is input, (to estimate the sum of the operation input U and the disturbance d) the first amount of the finding that is actually input to the controlled object 52. Controller _{53 32} is given by the filter _{Q 2.} Moreover, dividing the controller 53b to the two controllers ₅₃ 5, _{53 31} in series. Here, the controller 53 ₅ is provided by a filter _{Q 1.} The controller 53 ₃₁ has a filter Q ₂ and model transfer characteristic given by the product of the inverse of the transfer function G _imp corresponding to (model representing a desired response). The controller 53 _31, by the controlled variable y is input, obtains the second amount to be input to the controlled object 52.

As shown in FIG. 3 (C), the correction unit 53, two filters ₅₃ 12 are in a relationship where the output of each other to cancel, 53 _4, subtracter _{53 13} adds adder 53 _2. Filter ₅₃ 12, 53 ₄ is given by the transfer function _{Q 1.} Here, the transfer function Q ₁ is, to represent the phase lag that occurs in estimating the disturbance d by the controller 53 _11. Through the filter ₅₃ 12, 53 _4, the control input U is inputted to the respective subtractors _{53 13} and adder 53 _2. The subtracter _{53 13} calculates the difference between the outputs of the filter _{53 12} of the controller _{53 11,} i.e., estimates the disturbance d, the result is outputted to the adder 53 ₂ <d>. The adder 53 ₂ obtains a sum of the output of the subtracter _{53 13} output of the filter 53 _4, and outputs toward the result to the filter _{53 32.}

In FIG. 3 (C), the controller _{53 11,} filter _{53 12} and the subtracter _{53 13,} estimates the disturbance d by entering the control input U and the controlled variable y, and outputs the result <d> constitute a disturbance observer 53 _1. The controller 53 ₃₁ , the filter 53 ₃₂ , and the subtractor 53 c receive the controlled amount y, the sum of the control input U and the estimation result of the disturbance <d> to obtain the correction amount, and output the result dU. constitute a disturbance observer 53 _3. Therefore, the block diagram shown in FIG. 3 (C) can be equivalently converted to the simple block diagram shown in FIG. 4 (A).

Finally, in FIG. 4 (A), the controlled variable y and the control input U, respectively via the filter ₅₃ 4, 53 ₅ having a filter function _{Q 1} equal to each other, and are input to the disturbance observer 53 _3. Therefore, to remove the filter ₅₃ 4, 53 _5. Thereby, the block diagram shown in FIG. 4 (B) is derived. Note that this control system is equal to the target R = 0 in the control system 50 'shown in FIG. In other words, in the control system 50, by further adding the target generator 51 _0, it can be derived a control system 50 'shown in FIG. Accordingly, the control system 50 '(correction unit 53') is equivalent to the control system 50 (correction unit 53) shown in FIG.

The control system 50 'in the above FIG. 4, the disturbance observer 53 _1, for example, a disturbance as a step-like disturbance can be designed based on the minimum dimension observer design according to the method of Gopinath. Here, the motion of a nominal model (a model that reproduces the actual response of the control target 52) used for design is given by a function P _n1 (= P _n ) = 1 / Ms ² that represents the free translational motion of a rigid body having a mass M . (A characteristic equal to the characteristic of the control object 52 (actual plant characteristic) P = 1 / Ms ² adopted in the simulation to be described later is adopted.) The disturbance observer 53 ₁ is used to estimate the disturbance d. The actual input U + d of can be estimated. However, the set to be higher than the bandwidth of the disturbance observer 53 ₃ band of the disturbance observer 53 _1.

Disturbance observer 53 _3, like the disturbance observer 53 ₁ can be designed based on the minimum dimension observer design according to the method of Gopinath. Here, a transfer function P _n2 (= G _imp ) representing the translational motion of a rigid body having a mass M _n , a viscosity C _n , and an elasticity K _n , the motion of a nominal model (model representing a desired response) used in design. = 1 / (M _n s ² + C _n s + K _n ). Deviation of the response of the control object 52 from the response represented by the nominal model P _n2 by using the disturbance observer 53 _3, that is, the correction amount dU obtained for the control input U.

By correcting the control input U using the determined deviation dU, it becomes possible to suppress only the plant fluctuation without suppressing the disturbance d. Incidentally, by designing the disturbance observer 53 ₃ using any model, the response characteristic of the controlled object 52 from the disturbance d to the output y is within the band, the desired properties are expressed by the arbitrary model Take on.

As a method of designing a disturbance observer 53 _1, 53 _3, not limited to the method described above Gopinath, actually many may be a variety of methods have been proposed to employ in the literature. In the description above has been designed in two of the disturbance observer 53 _1, 53 ₃ a continuous-time system, it is also possible to design in a discrete time system.

The simulation result of the frequency response characteristic of the control object 52 from the disturbance d to the output y is shown in FIG. Here, the response characteristic (actual plant characteristic) of the controlled object 52 is given by the characteristic P = 1 / Ms ² . The table given in FIG. 6 shows values of physical parameters adopted in the simulation. Pole of the disturbance observer ₅₃ 1, 53 _3, respectively, and a multiple root of the multiple roots and 50Hz of 150 Hz. In order to simulate the response of the control object 52 to the disturbance d, the drive target R = 0.

In FIG. 5, the solid line (black) is the response characteristic P of the actual control object 52, the solid line (grey) is the response characteristic P _n2 of the desired control object represented by the model, and the broken line is the control object 52 from the disturbance d to the output y. Shows the response characteristic (d → y with prop) of The response characteristic P of the control object 52 is given by a model (P = 1 / Ms ² ) representing the free translational motion of a rigid body having a mass M as a condition of simulation. Stay constant. On the other hand, the desired response characteristic P _n2 is a function (P _n2 = 1 / (M _n s ² + C _n s + K _n ) representing the translational motion of a rigid body having a mass M _n , a viscosity C _n , and an elasticity K _n Therefore, the amplitude and phase are maintained almost constant by the effect of the elastic K _{n in} the low frequency band (a band of about 0.01 Hz or less), and the viscosity C _n in the middle frequency band (a band of about 0.01 to 10 Hz) According to the response characteristics of the controlled object 52, a slight deviation is seen in the high frequency band (approximately 10 Hz or more) in both the amplitude and the phase. shows a behavior substantially equal to the desired response characteristic (P _n2). this result, by the control system 50 of the present embodiment, the response of the controlled object 52 against an external force d, outer Suggesting that can be modified to respond with any viscoelastic properties represented by the model used in the observer 53 ₃ design (transfer function P _n2).

FIG. 7 shows simulation results of time response characteristics. FIG. 7A shows an external force d that acts on the control target 52. As the external force d, an impulse-like force having an amplitude of 10 (N) and a time width of 0.01 (s) at time t = 1 (s) is applied to the control object 52. FIG. 7B shows an output (position y) from the control target 52 (sensor 52 ₂ ) when the control system 50 of the present embodiment is not adopted. In this case, since the control target 52 does not have visco-elastic characteristics, it continues to move at constant velocity to infinity by the action of the disturbance d. In FIG. 7 (C), showing the desired response characteristics to expect the control target 52, i.e. the response characteristic represented by the model (transfer function P _n2) used in the design of the disturbance observer 53 _3. The controlled object 52 moves to a fixed distance (approximately 1 mm) before time 0.5 (s) elapses by the action of the disturbance d by adding the viscoelastic characteristic (C _n , K _n ), and then, Gradually return to the original position. FIG. 7D shows the response characteristic of the control target 52 when the control system 50 of the present embodiment is adopted. It can be seen that the characteristics substantially match the desired response characteristics shown in FIG. 7 (C). FIG. 7E shows a control input (driving force) U applied to the control target 52 when the control system 50 of the present embodiment is adopted. The control input (driving force) U shows an impulse-like force (reaction force) and an overshoot (hunting) following it in a direction to cancel the external force d at time t = 1 (s). By inputting the control input U shown in FIG. 7 (E) to the control object 52 for the disturbance d shown in FIG. 7 (A), the control object 52 virtually has visco-elastic characteristics (C _n , K _n ) It turns out that it responds as a rigid body which it has.

As described above in detail, according to the control system (basic configuration) 50 of the first embodiment, the nominal model (controlled object 52 that represent the controlled amount y, the controlled object 52 to be measured by the sensor 52 ₂ Of the quantity to be input to the controlled object 52 on the basis of a model that reproduces the actual response of the vehicle, and the desired response of the controlled object 52 to the disturbance d, ie, the disturbance d and the object A model expressing a desired relationship with the control amount y) An amount to be input to the control object 52 is determined based on G _imp , a correction amount for correcting the control input is determined from the difference between these two amounts, and the result is The control input U is corrected using this. By correcting the control input U, the response of the control object 52 is corrected to the desired response represented by the model G _imp . Thereby, even if the disturbance d acts, it is possible to drive the control object 52 precisely and stably.

Further, according to the control system of the first embodiment (modified configuration) 50 'obtains the disturbance d applied to the controlled object 52 by the disturbance observer 53 _1, using the control input U to be input to the controlled object 52 as a result and obtains the deviation of the response of the control object 52 from the model (transfer function P _n2) representing the desired response by the disturbance observer 53 ₃ Te, the control input U is corrected using the result. By correcting the control input U using the deviation from the response represented by the nominal model P _n2 of the response of the controlled object 52, the response of the controlled object 52 is corrected to the desired response represented by the nominal model P _n2 Be done. Thereby, even if the disturbance d acts, it is possible to drive the control object 52 precisely and stably.

Further, according to the control system 50, 50 'of the first embodiment, the control object 52 is obtained by giving a model representing translational movement of a rigid body having mass, viscosity, and elasticity as the model G _imp and the nominal model P _n2. against disturbance d acting, it is possible to drive and control the controlled object 52 as a rigid body having a virtually viscoelastic properties (C _{n, K n).}

Furthermore, 'according to the correcting unit 53 to obtain a correction amount dU with respect to the control input U' control system 50 of the first embodiment, and can be configured simple by using two of the disturbance observer 53 _1, 53 ₃ . Here, first one of the disturbance observer 53 _1, and an output (control input) U of the sensor 52 and _second output (the controlled variable) y and stage controller 51, and estimates the external force d of the controlled object 52 from the outside is subjected . The second disturbance observer 53 _3, the output of the disturbance observer 53 ₁ (disturbance estimation) <d> and the output of the stage controller 51 (control input) and a U, virtually controlled object 52 is desired viscoelastic properties The correction amount dU which exhibits a response having.

Further, the control system 50 'of the first embodiment, it was decided to estimate the disturbance d acting on the controlled object 52 using the disturbance observer 53 _1. Thus, by utilizing the high response characteristic of the driving device 52 _1, the viscoelastic properties of the driven object against an external force d can be adjusted virtually fast response. Further, as the nominal model used in the disturbance observer 53 ₁ design, the actual response of the controlled object 52 by adopting a model that accurately reproduced, it is possible to estimate the disturbance d more accurately.

Incidentally, in the control system 50 'of the first embodiment is not limited to estimating the disturbance d by using the disturbance observer 53 _1, it is also possible to measure the disturbance d for example, using a force sensor. A case, the measurement result is input to the disturbance observer 53 _3. Furthermore, the disturbance observer 53 ₃ contains a predicted or measured disturbance d results (or their corresponding amount) correction amount dU with respect to the measurement result (or equivalent amount to) the control input U from the of the controlled variable y It is not necessary to design as a disturbance observer if it is required.

Second Embodiment
Hereinafter, the second embodiment will be described using FIGS. 8 to 13. Here, while using the same code | symbol to the component same as above-mentioned 1st Embodiment, detailed description is also abbreviate | omitted.

FIG. 8 shows the configuration of a control system 50 according to the second embodiment. The control by the control system 50 having this configuration is called IPFB (Impedance Parameterization Feedback) control. The control system 50 is a feedback control system that drives and controls the controlled object 52 by giving the control input U, as in the basic configuration and the modified configuration described above, and a sensor that measures the position y of the controlled object 52, which is a controlled variable. 52 and _2, a controller 54 for performing an operation to gain multiple (measurement results of the position y) output from the sensor 52 ₂ (-1 times), (and that has dimensions of position) the target position of the controlled object 52 R It generates a stage controller 51 and outputs the sum of the output of the target position R and the control unit 54 (i.e. the deviation between the measurement result of the position y of the control object 52 from the sensor 52 ₂₎ e, the stage controller 51 output obtain a correction amount from a correction unit 53 for transmitting the drive unit 52 ₁ for driving the controlled object 52 the result as the control input U, composed.

The control system 50 configured as described above has a configuration in which the stage control device 51 in the control system (modified configuration) 50 ′ is added to the control system (basic configuration) 50 according to the first embodiment. However, the subtractor 51 ₂ is replaced by a combination of the adder 51 ₃ and the controller 54. Therefore, assuming that the above-described ideal condition, that is, the response characteristic P of the control object 52 is equal to (the transfer function corresponding to the nominal model) Pn and assuming the ideal filter Q = 1, the response characteristic of the control object (from the external force d Characteristic up to output y) Pd (= y / d = SP) = G _imp is derived. That is, the target position R is generated by the stage control device 51 to drive the control target 52 to follow the target position R, and the correction unit 53 corrects the control input U, thereby the control system according to the first embodiment. Similar to 50, the response characteristic of the controlled object 52 can be corrected to the desired response represented by the model (transfer characteristic) _Gimp .

The performance of the control system 50 (IPFB control) according to the second embodiment is evaluated. A rigid model representing free translational motion of a rigid body having a mass is adopted as a nominal model representing the control object 52 (a model reproducing the actual response of the control object 52). Its transfer function is given by a function Pn = 1 / Ms ^2. (A characteristic equal to the actual plant characteristic described later is adopted.) A model expressing translational motion of a rigid body having mass, viscosity and elasticity is adopted as a model (a model expressing a desired response) exhibiting a desired behavior. . The transfer function is given by the function G _imp = 1 / (M _n s ² + C _n s + K _n ). As the filter Q, a second-order low pass filter Q = ω ² / (s ² + 2ζωs + ω) is adopted. The table given in FIG. 9 shows the values of physical parameters included in these models and the like.

The frequency response characteristic C ₅₃ of the correction unit ₅₃ is shown in FIG. Response characteristic C ₅₃ of the correcting unit 53, the amplitude increases with increasing frequency in the frequency band below the cut-off frequency 50Hz, has a maximum at the cutoff frequency 50Hz, a frequency at a cut-off frequency 50Hz or more frequency bands Decrease with the increase of Also, its phase increases with increasing frequency to a maximum at about 2 Hz, and decreases with increasing frequency to have a zero and further decrease at a cutoff frequency of 50 Hz.

The simulation result of the frequency response characteristic of the control object 52 from the disturbance d to the output y is shown in FIG. Here, the response characteristic (actual plant characteristic) of the controlled object 52 is given by the characteristic P = 1 / Ms ² .

In FIG. 11, the solid line (gray) is the response characteristic P of the actual control object 52, the solid line (black) is the response characteristic G _imp of the desired control object represented by the model, and the broken line (overlapping substantially the solid line) is the disturbance d. The response characteristic Pd of the controlled object 52 from the point y to the point y is shown. The response characteristic P of the control object 52 is given by a model (P = 1 / Ms ² ) representing the free translational motion of a rigid body having a mass M as a condition of simulation. Stay constant. On the other hand, the desired response characteristic G _imp is a function (G _imp = 1 / (M _n s ² + C _n s + K _n ) representing the translational movement of a rigid body having a mass M _n , a viscosity C _n and an elasticity K _n Therefore, the amplitude and phase are kept approximately constant by the effect of the elastic K _{n in} the low frequency band (a band of about 0.1 Hz or less), and the viscosity C _n in the middle frequency band (a band of about 0.1 to 100 Hz) The amplitude decreases slowly and the phase is delayed due to the effect of P. On the other hand, the result of the response characteristic Pd of the controlled object 52 shows a behavior that is substantially equal to the desired response characteristic G _imp in both amplitude and phase. this result, by the control system 50 of the present embodiment, the response of the controlled object 52 against an external force d, Ren represented by the model (transfer function G _imp) which exhibit the desired behavior Suggesting that it can be modified to respond with viscoelastic properties of.

The sensitivity characteristic of the control system 50 is shown in FIG. The sensitivity function S increases its amplitude with increasing frequency, keeping the amplitude constant in the band above about 10 Hz. The behavior of the sensitivity function S is also approximately the same as the function P ⁻¹ G _imp . That is, the response characteristic P of the control object 52 is equal to the nominal model (the transfer function corresponding to it) Pn, and the relation S = P ⁻¹ G _imp derived under the ideal condition assuming the ideal filter Q = 1 is a good approximation It consists of This suggests that position control of the control object 52 is also possible depending on the plant characteristic P and the impedance characteristic G _imp .

FIG. 13 shows another configuration of the control system 50 according to the second embodiment. Control by the control system 50 having this configuration is called PSFB (Plant Shaping Parameterization Feedback) control. The control system 50 is a feedback control system that drives and controls the controlled object 52 by giving the control input U, as in the basic configuration and the modified configuration described above, and a sensor that measures the position y of the controlled object 52, which is a controlled variable. 52 and _2, a controller 54 for performing an operation to gain multiple (measurement results of the position y) output from the sensor 52 ₂ (-1 times), (and that has dimensions of position) the target position of the controlled object 52 R It generates a stage controller 51 and outputs the sum of the output of the target position R and the control unit 54 (i.e. the deviation between the measurement result of the position y of the control object 52 from the sensor 52 ₂₎ e, the stage controller 51 and of generating a control input U from the output, so that the controller 51 ₄ to send a control object 52 to the drive unit 52 ₁ for driving the control from the output of the controller 54 (i.e., the output of the sensor 52 ₂₎ A correction unit 53 for obtaining a correction amount dU to forces U, composed.

The control system 50 having the above-described configuration includes a correction unit 53 in the inner loop with respect to the control system (basic configuration) 50 according to the first embodiment, and the stage control device 51 in the control system (deformed configuration) 50 ′ the controller 51 ₄ is configured by adding at outer loop. Here, the controller 51 ₄ generates a (measurement results of the deviation of the position y of the control object 52 according i.e. target position R and the sensor 52 ₂₎ controlled from e input U output of the stage controller 51, the result to output to the adder 51 _5. Correcting unit 53 calculates the correction amount dU with respect to the control input U from the output of the controller 54 (i.e. measurement result of the position y of the control object 52 from the sensor 52 _2), is output to the result to adder 51 ₅ . The adder 51 ₅ adds the correction amount dU outputted from the correction unit 53 to the control input U, which is outputted from the controller 51 ₄ is transmitted to the drive unit 52 ₁ for driving the controlled object 52 results.

The control system 50 having the above-described configuration is controlled under the above-described ideal condition, that is, assuming that the response characteristic P of the controlled object 52 is equal to the nominal model (the transfer function corresponding to it) Pn and the ideal filter Q = 1. Response characteristics (a characteristic from the control input U and the external force d to the output y) Pd (= y / U = y / d = SP) = G _imp is derived. That is, the target position R is generated by the stage control device 51 to drive the control target 52 to follow the target position R, and the correction unit 53 corrects the control input U, thereby the control system according to the first embodiment. Similar to 50, the response characteristic of the controlled object 52 can be corrected to the desired response represented by the model (transfer characteristic) _Gimp . Controller 51 ₄ is designed to precisely and stably driving the model (transfer _{function) G imp.} Thereby, it becomes possible to drive the control object 52 precisely and stably.

As described above in detail, according to the two control systems 50 according to the second embodiment, the stage control device 51 generates the target position R to drive the control target 52 to follow the target position R, By correcting the control input U by the correction unit 53, it is possible to correct the response characteristic of the control object 52 to a desired response represented by the model (transfer characteristic) _Gimp . Controller 51 ₄ is designed to drive precisely and stably to the correction model (transfer characteristic) G _imp. Thereby, it becomes possible to drive the control object 52 precisely and stably.

Third Embodiment
The third embodiment will be described below with reference to FIGS. 14 to 19.

  In the third embodiment, the control system (modified configuration) 50 'in the first embodiment is applied to an exposure apparatus 110 provided with a catapult-type stage device with some modification.

  FIG. 14 shows a schematic configuration of an exposure apparatus 110 used for manufacturing a flat panel display according to the present embodiment, for example, a liquid crystal display (liquid crystal panel). The exposure apparatus 110 drives the mask M and the glass plate (hereinafter referred to as a “plate”) P at the same speed in the same direction with respect to the projection optical system PL to make the pattern formed on the mask M a plate P It is a scanning stepper (scanner) that is transferred onto. In the following, the direction (scanning direction) in which the mask M and the plate P are driven at the time of scanning exposure is taken as the X axis direction, and the direction in the horizontal plane orthogonal to this is orthogonal to the Y axis direction, X axis and Y axis The directions of rotation are the Z-axis direction, the X-axis, the Y-axis, and the rotation (inclination) directions about the Z-axis are θx, θy, and θz directions, respectively.

  The exposure apparatus 110 includes an illumination system IOP, a mask stage MST for holding the mask M, a projection optical system PL, a body 70 for supporting them, a plate stage PST for holding the plate P, and a control system for these. The control system is composed of a main control unit (not shown) for overall control of each component of the exposure apparatus 110 and a stage control unit 51 under the control (see FIG. 15 etc.).

  The body 70 is composed of a base (anti-vibration table) 71, columns 72A and 72B, an optical surface plate 73, a support 74, and a slide guide 75. The base (vibration isolation stand) 71 is disposed on the floor surface F, and isolates vibrations from the floor surface F to support the columns 72A, 72B and the like. The columns 72A and 72B each have a frame shape, and the column 72A is disposed inside the column 72B. The optical surface plate 73 has a flat plate shape and is fixed to the ceiling of the column 72A. The support 74 is supported on the ceiling of the column 72B via a slide guide 75. The slide guide 75 includes an air ball lifter and a positioning mechanism, and positions the support 74 (that is, the mask stage MST described later) with respect to the optical surface plate 73 at an appropriate position in the X-axis direction.

  The illumination system IOP is disposed above the body 70. The illumination system IOP is configured in the same manner as the illumination system disclosed in, for example, US Pat. No. 5,729,331, and for example, light (illumination light) IL emitted from a light source (not shown) such as a mercury lamp. Is irradiated onto the mask M via a reflecting mirror, a dichroic mirror, a shutter, a wavelength selection filter, various lenses (all not shown), and the like. As illumination light IL, for example, light such as i-ray (wavelength 365 nm), g-ray (wavelength 436 nm), h-ray (wavelength 405 nm) or the like (or combined light of i-ray, g-ray and h-ray) is used. Further, the wavelength of the illumination light IL can be appropriately switched by the wavelength selection filter, for example, according to the required resolution.

  The mask stage MST is supported by a support 74 forming the body 70. On the mask stage MST, a mask M having a pattern surface (a lower surface in FIG. 14) on which a circuit pattern is formed is fixed, for example, by vacuum suction (or electrostatic suction). The mask stage MST is driven with a predetermined stroke in the scanning direction (X-axis direction) by a mask stage drive system MSD (see FIG. 16) including, for example, a linear motor, and in the non-scanning direction (Y-axis direction and θz direction) It is slightly driven.

  Position information (including rotation information in the θz direction) in the XY plane of the mask stage MST is measured by the mask interferometer system 16 (see FIG. 16). The measurement result is supplied to the stage control device 51 (see FIG. 15). The stage control device 51 drives the mask stage MST via the mask stage drive system MSD in accordance with the measurement result of the mask interferometer system 16.

  The projection optical system PL is supported by an optical surface plate 73 constituting the body 70 below the mask stage MST (−Z side). The projection optical system PL is configured in the same manner as the projection optical system disclosed in, for example, US Pat. No. 5,729,331, and a plurality of projection areas of the pattern image of the mask M are arranged in a zigzag, for example 7) including the projection optical system (multi-lens projection optical system) to form a rectangular image field having the Y-axis direction as the longitudinal direction. Here, four projection optical systems are disposed at predetermined intervals in the Y-axis direction, and the remaining three projection optical systems are disposed at predetermined intervals in the Y-axis direction with a distance from the four projection optical systems to the + X side. ing. As each of the plurality of projection optical systems, for example, one that forms an erecting correct image by a both-side telecentric equal-magnification system is used. A plurality of projection areas of the projection optical system PL arranged in a staggered manner are collectively referred to as an exposure area.

  When the illumination area on the mask M is illuminated by the illumination light IL from the illumination system IOP, the illumination light IL transmitted through the mask M causes a circuit pattern of the mask M in the illumination area via the projection optical system PL. A projection image (partial erect image) is formed on the irradiation area (exposure area (conjugate to the illumination area)) on the plate P disposed on the image plane side of the projection optical system PL. Here, a resist (sensitive agent) is applied to the surface of the plate P. The mask stage MST and the plate stage PST are synchronously driven, that is, the mask M is driven in the scanning direction (X-axis direction) with respect to the illumination area (illumination light IL), and the plate P is exposed to the exposure area (illumination light IL). By driving in the same scanning direction with respect to the plate P, the plate P is exposed to transfer the pattern of the mask M onto the plate P.

  The plate stage PST is disposed on a base (vibration isolation table) 71 below (on the -Z side) the projection optical system PL. The plate stage PST is driven on the base 71 with a predetermined stroke in the X-axis and Y-axis directions by a stage drive system PSD including a linear motor etc. and minutely driven in the Z-axis direction, θx direction, θy direction, and θz direction Be done. The plate P is held on the plate stage PST via a plate holder (not shown).

  Position information (rotation information (yaw amount (rotation amount θz in the θz direction), pitching amount (rotation amount θx in the θx direction), rolling amount (rotation amount θy in the θy direction)) of the plate stage PST in the XY plane Is measured by a plate interferometer system 18 (also simply referred to as an interferometer (FIG. 15)). The interferometer 18 irradiates a measuring beam from the optical surface plate to a movable mirror (or a mirror-finished reflecting surface (not shown)) provided at an end of the plate stage PST, and receives reflected light from the movable mirror Thus, the position of the plate stage PST is measured. The measurement result is supplied to the stage control device 51 (see FIG. 15). The stage control device 51 drives the plate stage PST via the stage drive system PSD in accordance with the measurement result of the interferometer 18.

  The configuration of a control system related to stage control of the exposure apparatus 110 is shown in FIG. The control system of FIG. 15 mainly includes a stage control device 51 including, for example, a microcomputer.

  In exposure apparatus 110, alignment measurement (for example, EGA etc.) is performed prior to exposure, and plate P is exposed in the following procedure using the result. First, in accordance with an instruction from the main controller (not shown), stage controller 51 starts scanning each position for starting scanning of mask stage MST and plate stage PST according to the measurement results of mask interferometer system 16 and plate interferometer system 18 (acceleration start Move to position). Next, both stages MST and PST are synchronously driven at the same speed in the same X-axis direction. As a result, the pattern of the mask M is transferred onto the first shot area on the plate P so as to overlap the pattern formed on the previous process layer. When the scanning exposure for the first shot area is completed, the stage control device 51 moves (steps) the plate stage PST to the scanning start position (acceleration start position) for the second shot area. At the same time, the driving direction of the mask stage MST is reversed. Then, scan exposure is performed on the second shot area. Similarly, the stage control device 51 repeats the stepping between the shot areas of the plate P and the scanning exposure for the shot areas to transfer the pattern of the mask M to all the shot areas on the plate P.

  The configuration of mask stage MST, mask stage drive system MSD (69, 71A, 71B, 71C, 80) and mask interferometer system 16 will be described in detail. These configurations and arrangements are shown in FIG.

  The mask stage MST is configured to include a fine movement stage 32 that holds and moves the mask M, and a coarse movement stage 34 that supports and moves the fine movement stage 32.

  Fine movement stage 32 has a rectangular shape in plan view (as viewed from above). A rectangular opening (not shown) through which the illumination light IL passes is formed substantially at the center of the fine movement stage 32, and a plurality of (for example, four) vacuum chucks (not shown) are provided around it. The mask M is held on the fine movement stage 32 by vacuum suction using these vacuum chucks. Gas static pressure bearings (not shown) are respectively provided at four corners of the lower surface of fine adjustment stage 32. The fine moving stage 32 is floated and supported on (the guide surface formed on the upper surface of) the support 74 via a clearance of about several micrometers by these static gas bearings. Moving mirrors 17X and 17Y are provided on the + X end surface and the -Y end surface of fine movement stage 32, respectively. In place of the movable mirror, the end face of the stage may be mirror-finished to form a reflection surface.

  The coarse movement stage 34 has an L shape in plan view, and is fixed to the -Y end of the mover 72 constituting the linear motor 69 in a cantilever manner.

  The mask stage drive system MSD includes a linear motor 69 for driving the coarse movement stage 34 in the Y-axis direction, voice coil motors 71A, 71B, 71C for driving the fine movement stage 32 with respect to the coarse movement stage 34, and the coarse movement stage 34. And the gas flow device 80 that suppresses the reaction force acting on the fine movement stage 32 by driving the

Linear motor 69 is configured to include a stator 69 ₁ supported on the support 74, the movable element 69 ₂ along the stator 69 ₁ moves in the X-axis direction, from. The stator 69 ₁ has a prismatic shape that the X-axis direction is the longitudinal direction, is supported on the support 74 in a non-contact manner through an air bearing or the like. The stator 69 _1, a plurality of armature coils (not shown) are arranged in the X-axis direction. Mover 69 ₂ has a casing that the X-axis direction is the longitudinal, coarse movement stage 34 is fixed to the -Y end. The mover 69 _2, include magnetic member having a YZ cross-section of inverted U-shaped (U-shaped). On an inner pair of opposing surfaces of the magnetic member, a plurality of permanent magnets (not shown) are arranged in the X-axis direction with different magnetic pole surfaces facing each other and alternately facing different magnetic pole surfaces.

Linear motor 69 includes a stator 69 ₁ and the mover 69 _2, configured as a moving magnet type linear motor for driving the coarse movement stage 34 in the X-axis direction. Stage controller 51 by using the linear motor 69, i.e., controls driving of the coarse movement stage 34 by controlling the exciting current for exciting the armature coils of the stator 69 in _one. Note that a plurality of permanent magnets in the stator 69 _1, provided with a plurality of armature coils to the movable member 69 within ₂ may constitute a moving coil type linear motor.

The voice coil motor 71A is composed of a stator 71A ₁ and mover 71A _2. The stator 71A ₁ is fixed to the -Y end surface of the coarse movement stage 34. The stator 71A _1, magnetic member (not shown) having a YZ cross-section of a substantially U-shaped (U-shaped) are included. On a pair of opposing surfaces (upper and lower opposing surfaces) of the magnetic member, a plurality of permanent magnets (not shown) are arranged in the Y-axis direction with different magnetic pole surfaces facing each other and alternately different magnetic pole surfaces facing each other. Mover 71A ₂ is fixed to the + Y end surface of the fine movement stage 32. Mover 71A ₂ has a flat plate shape, a plurality of armature coils (not shown) are arranged in the Y-axis direction inside thereof. By the mover 71A ₂ is engaged with the stator 71A ₁ (by being positioned in the space substantially U), it is arranged in a magnetic field which armature coils emitted a plurality of permanent magnets. Thereby, the mover 71A ₂ (fine movement stage 32) can be minutely driven in the Y-axis direction with respect to the stator 71A ₁ (coarse movement stage 34).

The voice coil motors 71B and 71C are also configured similarly to the voice coil motor 71A. That is, the voice coil motor 71B (71C) is composed of a stator 71B ₁ (71C ₁ ) and a mover 71B ₂ (71C ₁ ). The stator 71B ₁ (71C ₁ ) is fixed to the + Y side (−Y side) of the + X end surface of the coarse movement stage 34 (arm portion). The mover 71 </ _b > B ₂ (71 C ₂ ) is fixed to the + Y side (−Y side) of the −X end surface of the fine movement stage 32. By moving the movers 71B ₂ and 71C _{2 to the} stators 71B ₁ and 71C ₁ (by being disposed in the substantially U-shaped space), the movers 71B ₂ and 71C ₂ (fine movement stage 32) The stators 71B ₁ and 71C ₁ (coarse motion stage 34) can be finely driven in the X-axis direction and the θz direction.

The stage control device 51 controls the fine movement stage 32 by controlling the excitation current which excites the armature coils in the movers 71A ₂ , 71B ₂ , 71C ₂ using the voice coil motors 71A, 71B, 71C. Do.

Gas flow device 80 is composed of a fixed portion 80 ₁ and the movable portion 80 _2. Fixing unit 80 ₁ is secured between the stator _71B 1, 71C ₁ of + X end surface of the coarse movement stage 34 (arm portions). The movable portion 80 ₂ is fixed between the movable element _71B 2, 71C ₂ of the -X end surface of the fine movement stage 32.

Figure 17 shows details of the configuration of the gas flow device 80 (fixing unit 80 ₁ and the movable portion 80 _2). Fixing unit 80 ₁ has a rectangular parallelepiped housing 81, the housing 81 inside the -X inner surface and the + X inner surface a pair of which is fixed to the gas ejection mechanism 82A, and 82B. The movable portion 80 _2, an arm 83 projecting from the -X end surface of the fine movement stage 32, a plate-like member which is disposed fixed to the distal end of the arm 83 (-X end) of the gas ejection mechanism 82A, while the 82B It has 84 and. The arm 83 is inserted into the housing 81 via the opening 81 a provided in the housing 81 and the gas ejection mechanism 82B.

  The gas ejection mechanisms 82A and 82B eject the same amount of pressurized gas such as air, nitrogen, or helium toward the −X surface and the + X surface of the plate-like member 84, respectively. As a result, thrust in the X-axis direction acts on fine movement stage 32 with respect to coarse movement stage 34. Here, the thrust in the + X direction and the −X direction acting on the plate-like member 84 from the gas ejection mechanisms 82A and 82B is proportional to the square of the separation distance between each of the gas ejection mechanisms 82A and 82B and the plate-like member 84. . Therefore, when the plate member 84 is positioned at the center of the gas ejection mechanisms 82A and 82B, the total thrust acting on the plate member 84 is zero, and the plate member 84 retains its position. When the plate-like member 84 is located on the gas ejection mechanism 82A side, the thrust in the + X direction received from the gas ejection mechanism 82A outweighs the thrust in the −X direction received from the gas ejection mechanism 82B, ie, the total acting on the plate-like member 84 Since the thrust is in the + X direction, the plate member 84 is returned in the + X direction. On the other hand, when the plate member 84 is located on the gas ejection mechanism 82B side, the thrust in the -X direction received from the gas ejection mechanism 82B is superior to the thrust in the + X direction received from the gas ejection mechanism 82A, that is, acting on the plate member 84 The plate-like member 84 is returned in the -X direction because the total thrust to be directed is in the -X direction.

  When the fine movement stage 32 approaches the coarse movement stage 34 (when moving in the −X direction) by the gas flow device 80, the fine movement stage 32 exerts a thrust on the fine movement stage 32 in the direction (+ X direction) away from the coarse movement stage 34 When the stage 32 is separated from the coarse movement stage 34 (when moved in the + X direction), a thrust is exerted on the fine movement stage 32 in the direction (−X direction) approaching the coarse movement stage 34. As the gas flow device 80 functions in this manner, the reaction force acting on the fine movement stage 32 can be suppressed by driving the coarse movement stage 34. Therefore, generation of a large thrust by the voice coil motors 71A, 71B, 71C is not required.

  The amount of pressurized gas ejected from the gas ejection mechanisms 82A and 82B may be controlled by the stage control device 51 according to the position of the plate member 84, ie, the position of the fine movement stage 32 relative to the coarse movement stage 34. good.

The mask interferometer system 16 comprises interferometer units 16X ₁ , 16X ₂ , 16Y. Interferometer units 16X ₁ and 16X ₂ respectively irradiate the measurement beams to the + Y side and the −Y side of moving mirror 17X of fine movement stage 32, and receive the reflected light from moving mirror 17X, thereby making mask stage MST possible. Measure the position in the X-axis direction and the θz direction of The interferometer unit 16Y irradiates the movable mirror 17Y of the fine movement stage 32 with a measurement beam, and receives the reflected light from the movable mirror 17Y to measure the position of the mask stage MST in the Y-axis direction. The measurement result is supplied to the stage control device 51 as described above (see FIG. 15).

  18A and 18B show the configuration of a control system 50 ′ ′ that drives and controls the mask stage MST according to the third embodiment. The configuration of the control system 50 ′ ′ according to the first embodiment Because the configuration is similar to the configuration of the control system 50, the configuration will be described focusing on differences.

  The control system 50 ′ ′ is a feedback control system that drives and controls the fine movement stage 32 to be controlled by giving a control input U, and generates a drive target (having a dimension of driving force) R of the fine movement stage 32. The stage control device 51 calculates the control input U using the result (and the correction amount dU described later) and transmits the result to the mask stage drive system MSD (voice coil motor 71A, 71B, 71C). From the mask interferometer system 16 described above for measuring the position X, Y, θz of the mask stage MST (fine movement stage 32), which is the control amount, and the output of the mask interferometer system 16 (measurement results of position X, Y, θz) A correction unit 53 ′ for obtaining a correction amount dU for the control input U, and a switch 55 for connecting the output of the correction unit 53 ′ to the stage control device 51 Be done.

  The mask stage drive system MSD (voice coil motors 71A, 71B, 71C) generates a driving force equal to its driving amount in accordance with the received control input U (having a dimension of force in the present embodiment). Thus, the fine movement stage 32 is driven and controlled with respect to the coarse movement stage 34. Note that d shown in the figure is a disturbance that acts on the fine movement stage 32 from the outside and is unknown. The control input U and the positions X, Y and θz are respectively an input and an output for the fine movement stage 32, both of which are known. The actual input to fine movement stage 32 is the sum of control input U (equal to the driving force emitted by voice coil motors 71A, 71B, 71C) output from stage control device 51 and disturbance d.

Stage controller 51 includes a target generator 51 ₀ and the switch 51 ₁ and the subtractor 51 _2. Drive target of the fine movement stage 32 target generator 51 ₀ generated (target with the dimensions of the driving force in this case) through the switch 51 ₁ is supplied to the subtracter 51 _2.

The correction unit 53 ′ is the same as the configuration of the correction unit 53 ′ according to the first embodiment. The output (correction amount dU) of the correction unit 53 ′ is output toward the stage control device 51 (subtractor 51 ₂ ) via the switch 55.

  Coarse movement stage 34 driven by a relatively large driving force on mask stage MST of the above configuration, that is, on support 74 (the guide surface formed on the upper surface), and supported by coarse movement stage 34 to drive precisely In the coarse and fine movement type mask stage MST configured with the fine movement stage 32 to be driven, the driving force of the coarse movement stage 34 (linear motor 69) is moved to the high speed stage to drive the fine movement stage 32 holding the mask M at high speed. The catapult driving method added to 32 can be adopted. Here, since the reaction force of fine movement stage 32 received from coarse movement stage 34 is suppressed as long as gas flow device 80 functions, fine movement stage 32 does not contact coarse movement stage 34 (force F (= collision force) 0) keep separate state). However, the strong driving force of coarse movement stage 34 (linear motor 69) is applied to fine movement stage 32 to exceed the functional limit of gas flow device 80, and fine movement stage 32 contacts coarse movement stage 34 (force F Chattering (mechanical vibration) may occur.

When the mask M (mask stage MST) is driven at a constant speed to expose the plate P, the gas flow device 80 functions sufficiently, the fine movement stage 32 does not contact the coarse movement stage 34, and the fine movement stage is coarse. Since the force (i.e., the external force d) due to the collision received from the moving stage is zero, the correction of the control input U by the correction unit 53 'is not necessary. Therefore, the control system 50 ', at a constant speed movement of the mask stage MST, 18 turns on the switch 51 ₁ in the stage controller 51 (A), a fine movement stage that target generator 51 ₀ generated 32 drive target R is supplied to the subtractor 51 _2, turn off the switch 55, blocking so that the output from the correction unit 53 '(the correction amount dU) is not output to the stage controller 51 (subtractor 51 ₂₎ Do.

On the other hand, when the mask M (mask stage MST) is accelerated or decelerated by the catapult driving method to step the plate P and change the driving direction of the mask M in the opposite direction, the function of the gas flow device 80 is exceeded and fine movement Since the stage 32 may contact the coarse movement stage 34 and receive a force (external force d) F due to a collision from the coarse movement stage (outside), the correction of the control input U by the correction unit 53 'is required. However, the drive target R of the fine movement stage 32 becomes unnecessary. Therefore, the control system 50 ', during acceleration and deceleration of the mask stage MST, as shown in FIG. 18 (B), the fine movement stage by turning off the switch 51 ₁ in the stage control unit 51, target generator 51 ₀ generated 32 drive target R is cut off so as not to be supplied to the subtracter 51 _2, turn on the switch 55, inputs the output from the correcting unit 53 '(the correction amount dU) to the stage control unit 51 (the subtractor 51 ₂₎ Do.

  FIGS. 19A and 19B respectively show simulation results of the reaction force and the position error that the fine adjustment stage 32 receives when the coarse adjustment stage 34 collides with the fine adjustment stage 32. When the control system 50 ′ ′ of the third embodiment is not adopted (w / o DDOB), the coarse movement stage 34 does not have virtual visco-elastic characteristics, so the coarse movement stage 34 By colliding with the fine movement stage 32, a large reaction force of -150 N is generated on the fine movement stage 32, a violent shaking (chattering) occurs until time 0.2s, and the reaction force is gently attenuated by time 0.5s. The position error flies up to about 500 μm due to the collision, shows overshoot (hunting) until time 0.15s, and keeps almost constant after time 0.2s.

  On the other hand, when the control system 50 '' of the third embodiment is adopted (with DDOB), the fine movement stage 34 moves slightly at time 0.05 s because the fine movement stage 32 has virtual visco-elastic characteristics. By colliding with the stage 32, a large reaction force of -150 N is generated on the fine movement stage 32, a violent shaking (chattering) is generated until time 0.1s, and the reaction force gradually increases at time 0.1 to 0.25s. The position error jumps to about 500 μm due to the collision, shows overshoot (hunting) until time 0.10s, and keeps almost constant after time 0.1s. By adopting control system 50 ′ ′, the reaction force received by fine movement stage 32 is reduced, that is, the chattering amplitude is reduced and the period thereof is shortened. The amplitude of the hunting which the position error shows is also small and the period is also short.

  As described above in detail, according to the control system 50 ′ ′ of the third embodiment, when the fine movement stage 32 moves in contact with the coarse movement stage 34 and accelerates (if it can contact), the correction from the control input U is corrected The output (correction amount dU) of the portion 53 'is reduced, so that the fine movement stage 32 is driven so that the visco-elastic characteristics virtually function with respect to the force (external force) caused by the collision of the fine movement stage 32 from the coarse movement stage 34. Thus, chattering due to a collision can be suppressed, and the fine movement stage 32 can be driven precisely and stably.

When driving mask M (mask stage MST) at a constant speed, the output of first disturbance observer 531 is a stage without second disturbance observer 533 instead of turning off switch 55 in FIG. It may be configured to be able to output to the control device 51 (subtractor 512). Thus, since the control input U to the first output of the disturbance observer 53 ₁ (disturbance) is subtracted is corrected from the control input U, to offset the external force fine movement stage 32 receives from the other coarse movement stage 34 virtually Thus, the fine movement stage 32 can be driven. As a result, fine movement stage 32 can be driven precisely and stably.

  Further, since the exposure apparatus 110 according to the present embodiment includes the control system 50 ′ ′ of the mask stage MST designed as described above, the mask stage MST can be driven precisely and stably, and the exposure accuracy, ie, The overlay accuracy can be improved.

  In the third embodiment, the control system 50 '' is supported by the coarse movement stage 34 which is driven by a large driving force on the support 74 (the guide surface formed on the upper surface thereof) and the coarse movement stage 34 Although applied to the drive control of the coarse / fine movement type mask stage MST configured of the fine movement stage 32 driven precisely, the fine movement stage holding and moving the plate P and the fine movement stage supporting and moving The present invention may be applied to drive control of a coarse / fine movement type plate stage, which makes it possible to drive the fine movement stage precisely and stably, and to improve the exposure accuracy, that is, the overlay accuracy.

  Further, in the third embodiment, the control system (modified configuration) 50 ′ in the first embodiment is adopted as the control system 50 ′ ′, but the control system 50 in the second embodiment may be adopted.

  In addition to the mask interferometer system 16 and the plate interferometer system 18, for example, a head provided to the optical surface plate 73 is used to irradiate measurement light to the scale provided to the mask stage MST or the plate stage PST, It is also possible to use an encoder that receives the return light.

  Further, the configurations of the mask interferometer system 16 and the plate interferometer system 18 are not limited to the above-described configurations, and a configuration in which an interferometer is added as appropriate can be adopted according to the purpose. Also, an encoder (or an encoder system composed of a plurality of encoders) may be used in place of or together with the mask interferometer system 16 and the plate interferometer system 18.

In the third embodiment, the illumination light is ultraviolet light such as ArF excimer laser light (wavelength 193 nm) or KrF excimer laser light (wavelength 248 nm) or vacuum ultraviolet light such as F ₂ laser light (wavelength 157 nm). It may be. In addition, as illumination light, for example, single wavelength laser light in the infrared region or visible region oscillated from a DFB semiconductor laser or fiber laser is amplified by a fiber amplifier doped with, for example, erbium (or both erbium and ytterbium) Alternatively, harmonics of which wavelength is converted to ultraviolet light using a non-linear optical crystal may be used. Also, a solid state laser (wavelength: 355 nm, 266 nm) or the like may be used.

  In the third embodiment, the projection optical system PL is a multi-lens type projection optical system including a plurality of optical systems. However, the number of projection optical systems is not limited to this. There should be at least three. Further, the projection optical system is not limited to the multi-lens type projection optical system, and may be, for example, a projection optical system using a large offner type mirror. Further, in the above embodiment, the projection optical system PL has been described as being used in the same magnification system as the projection optical system PL. However, the present invention is not limited to this. The projection optical system may be either an enlargement system or a reduction system.

  Also, the third embodiment (of the stage drive system) can be applied to any of a scanning exposure apparatus such as a batch exposure type or a scanning stepper, and a stationary exposure apparatus such as a stepper. The above embodiments can also be applied to a step-and-stitch projection exposure apparatus that combines a shot area and a shot area. The above embodiments can also be applied to a proximity type exposure apparatus that does not use a projection optical system, or to an immersion type exposure apparatus that exposes a substrate via an optical system and a liquid. can do. Besides, each of the above embodiments combines the two patterns on the substrate through the projection optical system, and exposes one shot area on the substrate substantially simultaneously double exposure by one scan exposure (US It can apply also to the patent 6,611,316 specification etc.).

  Further, the application of the exposure apparatus is not limited to an exposure apparatus for liquid crystal which transfers a liquid crystal display element pattern to a square glass plate, and, for example, an exposure apparatus for semiconductor manufacture, a thin film magnetic head, a micromachine and a DNA chip The present invention can be widely applied to an exposure apparatus for manufacturing a light source, etc. In addition, in order to manufacture not only micro devices such as semiconductor devices but also masks or reticles used in light exposure devices, EUV exposure devices, X-ray exposure devices, electron beam exposure devices, etc., glass substrates or silicon wafers etc. The above embodiments can also be applied to an exposure apparatus that transfers a circuit pattern to the The object to be exposed is not limited to the glass plate, and may be another object such as a wafer, a ceramic substrate, or a mask blank.

  The electronic device such as a liquid crystal display element (or semiconductor element) has a step of designing function and performance of the device, a step of fabricating a mask (or reticle) based on the designing step, a step of fabricating a glass plate (or wafer) An exposure apparatus according to each of the above-described embodiments, a lithography step of transferring a pattern of a mask (reticle) to a glass plate by the exposure method, a development step of developing an exposed glass plate, and portions other than resist remaining portions. It is manufactured through an etching step of etching away the exposed member of the portion, a resist removing step of removing the unnecessary resist after etching, a device assembling step, an inspection step and the like. In this case, in the lithography step, the exposure method described above is performed using the exposure apparatus of the above embodiment, and the device pattern is formed on the glass plate, so that a device with high integration can be manufactured with high productivity. .

  Although the exposure apparatus has been described as an example in the embodiment, the invention can be applied to other than the exposure apparatus. For example, if it applies to the vibration isolation apparatus in which a measuring apparatus etc. are mounted, it is possible to improve vibration isolation efficiency.

16 (16X, 16Y) ... mask interferometer system (interferometer unit), 18 ... plate interferometer system (interferometer), 32 ... fine movement stage, 34 ... coarse movement stage, 50, 50 ', 50 "... control system, 51 stage control device 51 ₀ target generation unit 51 ₁ switch 51 ₂ subtractor 52 control object 53, 53 'correction unit 53 ₁ 53 ₃ disturbance observer 53a 53b Controller, 55: switch, 69: linear motor, 71A, 71B, 71C: voice coil motor, 110: exposure device.

Claims (17)

A control system that generates an operation amount of the control target from a control target amount of the control target,
An input unit to which the controlled amount is input;
The first amount determined from the controlled amount or the generated amount generated by calculation using the controlled amount and the first model corresponding to the controlled object, and the generated amount and the first model are different. A control unit that generates the manipulated variable using a difference between the second model and a second quantity determined from a second model;
Equipped with
In the second model, the disturbance applied to the control target and the controlled amount are represented by a predetermined function.
The control unit has a disturbance observer including the second model, and the disturbance observer inputs a third amount determined from the first amount and the operation amount and the controlled amount, and performs the operation. Control system that outputs a correction amount to correct the amount.   The control system according to claim 1, wherein the function represents translational movement of a rigid body having mass, viscosity, and elasticity.   The control system according to claim 1, wherein the first model represents free translation of a rigid body having a mass.   The control unit has a second disturbance observer including the first model, and the second disturbance observer obtains the first amount based on the controlled amount and the operation amount. Or the control system as described in 3.   The control system according to any one of claims 1 to 4, further comprising: a target unit that generates a target amount related to the position of the control target, and outputs a difference between the target amount and the controlled amount as the generation amount. . A target unit that generates a target amount related to the position of the control target, and outputs a difference between the target amount and the controlled amount;
A controller that generates the manipulated variable using an output of the target unit;
The control system according to any one of claims 1 to 4, further comprising an adder that adds the difference between the first amount and the second amount and the operation amount. When the control target is in contact with another member, the operation amount is generated using a difference between the first amount and the second amount.
The control system according to claim 5 or 6, wherein when the control target is separated from the other member, the operation amount is generated using the output of the target portion. An exposure apparatus for exposing an object with an energy beam to form a pattern on the object, comprising:
A moving mechanism having a first movable body that holds and moves the object, and a second movable body that is movable relative to the first movable body while supporting the first movable body;
The control system according to any one of claims 1 to 7, wherein the first moving body is the control target;
An exposure apparatus comprising: A control method for controlling a control target that receives an operation amount and outputs a controlled amount,
Obtaining information on the position of the control target as the controlled variable;
Determining a first amount to be input to the control target from the control target or a generation amount generated by calculation using the control target, and a first model corresponding to the control target;
Determining a second amount input to the control target from the generation amount and a second model different from the first model;
Generating the manipulated variable using the first quantity and the second quantity,
In the second model, the disturbance applied to the control target and the controlled amount are represented by a predetermined function.
In the generation, a correction amount for correcting the operation amount by inputting a third amount and the controlled amount obtained from the first amount and the operation amount by a disturbance observer including the second model. Control method to output   The control method according to claim 9, wherein the second model represents translational movement of a rigid body having mass, viscosity, and elasticity.   The control method according to claim 9 or 10, wherein the first model represents free translation of a rigid body having a mass.   The control method according to claim 9 or 11, wherein in the generation, the first amount is obtained based on the controlled amount and the operation amount by a second disturbance observer including the first model.   The control method according to any one of claims 9 to 12, further comprising: generating a target value regarding the position of the control target, and generating the generation amount from a difference between the target value and the controlled amount. Generating a target value related to the position of the control target, outputting a difference between the target value and the controlled quantity, and generating the manipulated variable using the output;
The control method according to any one of claims 9 to 11, further comprising adding the difference between the first amount and the second amount and the operation amount. When the control target is in contact with another member, the operation amount is generated using a difference between the first amount and the second amount.
The control method according to claim 13 or 14, wherein the operation amount is generated using the output when the control target is separated from the other member. An exposure method for exposing an object with an energy beam to form a pattern on the object, comprising:
The first moving mechanism includes a first moving body that holds and moves the object, and a second moving body that is movable with respect to the first moving body while supporting the first moving body. An exposure method using the control method according to any one of claims 9 to 15, wherein a movable body is the control target. Forming a pattern on an object using the exposure method according to claim 16;
Developing the object on which the pattern has been formed;
A device manufacturing method including: