JPH0664481B2 - XY stage control device - Google Patents

Description

Description: TECHNICAL FIELD OF THE INVENTION The present invention relates to an XY stage used in a precision machine tool, a precision measuring machine, a semiconductor manufacturing apparatus, and the like.
The present invention relates to an XY stage control device for moving and positioning a moving stage to a target position on a table.

<Outline of the Invention> In the XY stage control device of the present invention, the notch frequency of the notch filter for absorbing the gain of the resonance motion of the moving stage is automatically variably set according to the stage position. This improves the control performance of the XY stage and its stability.

<Background of the Invention> Conventionally, as shown in FIG. 4, this type of XY stage has a horizontal table 21 on which movable guides 22 and 23 crossing each other vertically and a moving stage 24 are arranged at the crossing points. Is.
The movable guides 22 and 23 and the moving stage 24 have air bearings 2
5,26,27 are supported in a non-contact manner in a floating state, and compressed air is sent to the bearings via air tubes (not shown). The moving stage 24 moves while being guided by the bearing guide surface on the table 1 due to the movement of the movable guides 22 and 23. If the planar shape of the bearing guide surface varies or the thrust varies depending on the stage position, the stage moves. Such as yawing and pitching when moving
It has a rotational motion mode outside the XY orthogonal components. Since these are uncontrollable modes that appear as resonance modes in the dynamic characteristics of the XY stage, in the conventional XY stage control device, as shown in FIG. 5, a notch filter (narrow band) having a notch frequency corresponding to the resonance mode is used. A filter) 28 is used in the output stage to reduce the influence of the resonance mode. Note that the configuration of FIG. 5 substantially corresponds to that of FIG. 1 which will be described later, and here, corresponding components are designated by the same reference numerals and the description thereof is omitted.

However, since the resonance frequency of the resonance mode varies depending on the position of the moving stage 24 on the table 21,
There is a problem that the frequency does not match the notch frequency, and there is a problem that the XY stage oscillates due to the disturbance resonance mode due to the frequency shift.

<Object of the Invention> The present invention is for solving the above problems,
By making the notch frequency of the notch filter variable so that the notch frequency and the resonance frequency of yawing and pitching always match, it is possible to provide an XY stage control device with improved XY stage control performance and stability. To aim.

<Structure and Effect of the Invention> In order to achieve the above object, in the XY stage control device of the present invention, a variable notch filter capable of variably setting a notch frequency for absorbing the gain of the resonance motion of the moving stage, and a table Switching means for inputting position information of the moving stage and outputting a switching signal for switching the notch frequency of the notch filter is provided.

According to the configuration of the present invention, even if the resonance frequency of yawing or pitching varies depending on the position of the moving stage on the table, this resonance frequency and the notch frequency of the notch filter can always match, so the notch filter The control effect of is obtained uniformly over the entire range of the stage, and thereby stable control of the moving stage without resonance can be realized over the entire movable range. Further, since the resonance of the moving stage is prevented, the control gain can be maximized, and the control performance can be improved.

<Description of Embodiments> FIG. 1 shows a configuration example of an XY stage control device according to the present invention.

In the illustrated example, the XY stage 1 is driven by a motor 2 such as a linear motor, and the control device for the XY stage 1 includes a position feedback loop 3 for feeding back the current position data X _R of the XY stage 1, A velocity feedback loop 4 for feeding back the current velocity data V _R of the XY stage 1 is included. In the position feedback loop 3, a deviation ΔX (this is called “position deviation data”) between the target position data X ₀ and the current position data X _R is calculated, and the XY stage is set so that the position deviation data ΔX becomes zero. Positioning control to a target position of 1 is performed. The position deviation data ΔX is integrated by the integrator 5 in order to make the steady position deviation zero, and then, in the next block 6, compensation for improving the control characteristic of the position feedback loop 3 is given. Gives the gain K _A.

The speed feedback loop 4 is for giving a damping element to the control system of the XY stage 1, and a block 8 provides compensation for improving the control characteristic of the speed feedback loop 4, and further a block 9 has a gain K _B. After that, the following variable notch filter 10 is configured to absorb the gain of the resonance motion of the XY stage 1. The variable notch filter 10 has its notch frequency switched and set according to the position of the XY stage 1.
Current position X _R of the ROM (Read Only M
signal for switching the notch frequency from the ROM 11 (hereinafter referred to as "switch signal")
Is output). Note in the figure, the block 12 is a block for calculating the current position X _R from the current velocity V _R, s represents a Laplace operator.

FIG. 2 shows a state in which a plurality of points (indicated by 1 to 25 in the figure) are set on the table 13 in the XY stage 1, and the frequency characteristic of the XY stage 1 at each of these points is measured in advance. Then, after obtaining the notch frequency of the variable notch filter 10 corresponding to each point, in the address area corresponding to each point of the ROM11, store the switching signal generation data for setting each notch frequency Is.

FIG. 3 shows a specific circuit example of the ROM 11 and the variable notch filter 10 (the portion indicated by the broken line 14 in FIG. 1). Variable notch filter 10 in the illustrated example, the two operational amplifiers 15 and 16, a plurality of capacitors C ₁ -C ₃ and the resistor R ₁ to R ₆ to produce a notch frequency at each point, the resistor R ₁ to R _Four
, And analog switches S _{1 to} S ₄ for generating a predetermined combined resistance R ₀ . The notch frequency f _N of this variable notch filter 10 is given by the following equation, and therefore, by turning on and off the analog switches S _{1 to} S ₄ , the notch frequency f _N changes to a predetermined value. Is obtained.

In FIG. 3, IN is an input terminal and OUT is an output terminal.

However, if the current position X _R of the XY stage 1 is given as address data to the inputs A _{0 to} A ₇ of the ROM 11, the ROM 11 outputs a switching signal of 4-bit configuration (D _{0 to} D ₃ ) according to the current position X _R. Is output, and the analog switches S _{1 to} S ₄ are turned on and off. Thus one of the resistors R ₁ to R ₄ are connected in series a predetermined combined resistance R ₀ is generated, the resistance R _0, the values of R ₆ and capacitors C _1, C _2, C ₃ of the XY stage 1 A notch filter having a notch frequency f _N according to the current position is formed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an XY stage control device according to the present invention, FIG. 2 is a diagram for explaining a notch frequency setting position in the XY stage, and FIG. 3 is a concrete circuit example of a notch filter. Fig. 4 is a perspective view showing the appearance of a conventional XY stage. Fig. 5 is a conventional XY stage.
It is a block diagram of a stage control device. 1 …… XY stage 10 …… Variable notch filter 11 …… ROM

Claims (3)

[Claims] 1. An XY in which a movable guide that crosses vertically and horizontally on a table and a moving stage are provided at the crossing points.
A controller for a stage, comprising a variable notch filter capable of variably setting a notch frequency for absorbing a gain of resonance movement of the moving stage, and a notch of the notch filter by inputting position information of the moving stage on a table. An XY stage control device comprising switching means for outputting a switching signal for switching the frequency. 2. The notch filter comprises a plurality of resistors for determining a notch frequency and an analog switch for changing a notch frequency by changing a combination of these resistors. XY stage control device described. 3. The XY stage control device according to claim 1, wherein the switching means is a ROM which inputs the current position of the moving stage on the table as address data and outputs the switching signal.