JPH0378010A - Positioning device - Google Patents

Abstract

PURPOSE:To suppress the influence of the drift of a measurement system and to prevent the system from vibrating in its stop state by judging the stop state of a driving system and varying the loop gain of a digital control system. CONSTITUTION:A rough moving part digital servo control system 102 finds a deviation ES from a rough moving part movement command value P5 inputted from an operation command system 101 which commands an object to perform desired operation and a rough moving part movement quantity B5 being the amount of the movement of the object which is inputted from a rough moving part movement amount detection system 106. A gain switching part 103 evaluates the command value PS to judge the stop state when the command value PS is O and selects a gain G2 (larger than a gain G1) when the command value PS is not O. An amplification part 104 amplifies the deviation ES with the selected gain G1 or G2 to find a rough moving part driving system command value XS and outputs it to a rough moving part driving system 105. A detection system 106 detects the amount of the movement of the object by the driving system 105 and sends it out to a servo control system 102.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a positioning device, and particularly to a positioning device that digitally processes servo system data processing.

[Conventional technology]

In the exposure equipment of the IC manufacturing process, a servo system with a coarse movement drive system using a motor drive and an encoder is operated to move the wafer between the wafer storage and the exposure equipment, and to align the mask and wafer. Since it is necessary to perform this with high precision, the servo system is operated by the fine movement part drive system that uses a piezoelectric element to drive the stage on which the wafer is placed and the fine movement part drive system that uses position measurement using a laser length measurement system.2 A stepwise structure positioning device is adopted.

The gain of the servo system by the coarse movement drive system of the conventional two-stage positioning device is always kept constant, and when the stage is positioned by the fine movement part drive system, the stage is kept at a constant position depending on the coarse movement drive system. The gain of the servo system by the coarse drive system was the same both when the stage was stopped and when the stage was positioned by the coarse drive system.

[Problem to be solved by the invention]

The conventional positioning device described above performs control with a constant gain regardless of the state of the coarse movement drive system, so even when the coarse movement drive system stops the stage at a fixed position, the encoder etc. Since the movement amount detection system picks up minute fluctuations due to unstable wobbling and generates a command value for the coarse moving section drive system, there is a drawback that minute vibrations are generated by the coarse moving section drive system after positioning.

[Means to solve the problem]

The positioning device of the present invention includes a motion command system that outputs a movement command value for instructing a target object to perform a desired motion, a drive system that moves the target object, and a movement detection system that detects the amount of movement of the target object. an amplification unit that amplifies the deviation between the movement command value and the movement amount detected by the movement detection system and provides it to the drive system; and a gain that lowers the gain of the amplification unit when the movement command value is O. It is configured to include a switching section.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing one embodiment of the present invention.

In FIG. 1, a coarse moving section digital servo control system 102 uses a coarse moving section movement command value Ps inputted from an operation command system 101 that instructs a target object such as a stage to perform a desired operation, and a coarse moving section movement amount detection system. The deviation Es is obtained from the coarse movement part movement amount Bs which is the movement amount of the object input from 106, and the coarse movement part movement command value Ps is evaluated in the gain switching part 103.
, when the coarse movement part movement command value Ps is O, it is determined that the state is stopped and the gain G1 is set, and when the coarse movement part movement command value Ps is other than O, the gain G2 (gain G1 is smaller than gain G2) is set. Then, the deviation Es is amplified by the selected gain G1 or G2 in the amplification section 104 to obtain a coarse movement section drive system command value Xs, which is output to the coarse movement section drive system 105. The coarse moving section movement amount detection system 106 detects the amount of movement of the object by the coarse moving section drive system 105 and sends it to the coarse moving section digital servo system 102 .

Next, the fine movement part digital servo control system 112 generates a fine movement part drive system command value from the fine movement part movement command value pb inputted from the operation command system 101 and the fine movement part movement amount Bb inputted from the fine movement part movement amount detection system 116. Find xb, fine movement part drive system 115
Output to. The fine movement part movement amount detection system 116 detects the movement amount of the fine movement part drive system 115 and fine movement part digital servo system 1.
Send on 12th.

Although the embodiment has shown a two-stage structure including a fine movement part drive system and a coarse movement part drive system, the present invention is not limited to a two-stage structure positioning device, and may include only a coarse movement part drive system. It is also applied to positioning devices, etc.

〔Effect of the invention〕

The positioning device of the present invention determines whether the drive system is stopped,
By changing the loop gain of the digital control system,
This has the effect of intentionally making the trackability of the stopped state worse, suppressing the influence of fluctuations in the measurement system, and eliminating vibrations in the stopped state.

lOl...Operation command system, 102...Coarse movement part digital navigation control system, 103...Gain switching unit, 1゜4
...Amplification section, 105...Coarse movement section drive system, 106...
- Coarse movement part movement detection system, 112... Fine movement part digital servo control system, 115... Fine movement part drive system, 116...
Fine movement part movement detection system.

Claims (1)

[Claims] an operation command system that outputs a movement command value for instructing a target object to perform a desired operation; a drive system that moves the target object;
a movement detection system that detects the amount of movement of the object; an amplification section that amplifies a deviation between the movement command value and the movement amount detected by the movement detection system and provides it to the drive system;
and a gain switching section that switches the gain of the amplifying section to a low value when the positioning device is set.