STATIONARY VIBRATION ISOLATION SYSTEM AND METHOD FOR ITS CONTROL

Description

Field of invention

[0001] The invention relates to a stationary vibration isolation system, a method for controlling it, and an isolator for a stationary vibration isolation system.

[0002] In particular, the invention relates to a stationary vibration isolation system on which a machine for processing semiconductor components and / or nanostructured elements, in particular wafers, masks or display substrates, or for measuring semiconductor components and / or nanostructured elements, such as an electron beam microscope, is arranged.

[0003] Furthermore, laboratory equipment and / or medical devices, such as imaging devices like magnetic resonance imaging (MRI) scanners, can also be arranged on the stationary vibration isolation system. Background of the invention

[0004] Stationary vibration isolation systems are used particularly in the semiconductor industry for mounting processing machines, such as lithography equipment and measuring devices, such as electron beam microscopes, in order to mount sensitive equipment for processing semiconductor components in a vibration-isolated manner.

[0005] Such a vibration isolation system usually consists of a plate which is mounted on at least three insulators, each comprising a spring, in a vibration-isolated manner.

[0006] The equipment for processing semiconductor components is arranged on the plate and is thus protected from vibrations. The plate and the equipment mounted on it together form the vibration-isolated load.

[0007] Active vibration isolation systems are particularly well-known in practice, in which the insulators include actuators, especially magnetic actuators, in addition to the spring, with which vibrations are actively counteracted.

[0008] Vibrations are detected by sensors, which can be located both at the base of the isolator and on the vibration-isolated load. Based on the sensor signals, the actuators are controlled to compensate for the vibrations by generating counterforces.

[0009] Using such active control, it is possible to counteract both vibrations propagating into the system from the outside and vibrations generated by the vibration-isolated load itself (e.g., by a movable stage or a moving robot).

[0010] Patent EP 2 295 829 B1 (Integrated Dynamics Engineering) shows a vibration isolation system in which actuators are provided to generate compensating forces in several degrees of freedom.

[0011] Such vibration isolation systems include a control unit (often also referred to as a controller) for processing the sensor signals, which detects the sensor signals and generates control signals based on the sensor signals, by means of which the actuators are controlled in order to generate compensation forces.

[0012] The control unit is designed as a central computing unit to which both the sensors and the actuators of all isolators of the vibration isolation system are connected.

[0013] This results in a high cabling effort. In particular, cables usually have to be laid from the control unit to the sensors, carrying such high currents, as the actuators that generate the counterforces can be controlled via these cables.

[0014] Furthermore, the maximum number of connectable insulators depends on the design of the control unit.

[0015] Each control unit is designed to accommodate a maximum number of isolators, which means that a vibration isolation system cannot be retrofitted with vibration isolators indefinitely without replacing the control unit.

[0016] Patent US 2009 / 078847 Al discloses a vibration isolation system with a plurality of insulators and actuators for active vibration damping. Object of the invention

[0017] In contrast, the invention is based on the objective of reducing the aforementioned disadvantages of the prior art.

[0018] In particular, a vibration isolation system should be provided which reduces the cabling effort and / or which can be flexibly scaled with regard to the number of isolators. Summary of the invention

[0019] The object of the invention is already solved by a stationary vibration isolation system, as well as by a method for controlling an active stationary vibration isolation system according to one of the independent claims.

[0020] Preferred embodiments and further developments of the invention can be found in the subject matter of the dependent claims, the description and the drawings.

[0021] The invention relates to a stationary vibration isolation system.

[0022] The stationary vibration isolation system comprises, in particular, a vibration-isolated machine for processing semiconductor devices and / or nanostructured elements. This could be, for example, a lithography machine, an optical wafer inspection machine, a measuring device such as an electron microscope, etc. Furthermore, a laboratory device or a medical device, especially a medical imaging device such as a magnetic resonance imaging (MRI) scanner, could also be vibrationally isolated on the vibration isolation system.

[0023] The vibration isolation system comprises a plurality of insulators by means of which a vibration-isolated load is supported.

[0024] In particular, the vibration isolation system comprises at least three insulators on which a vibration-isolated plate, which together with the equipment arranged on it forms the vibration-isolated load, is mounted.

[0025] The isolators are preferably effective in both the vertical and horizontal directions. The isolators can include a spring, in particular a pneumatic spring. Sensors, spring, and actuators can be integrated components of such an isolator or designed as separate units. In the latter case, the separate, and in particular spatially adjacent, units of sensors, spring, and actuators together form a logical unit that functions as an active vibration isolator, which not only acts as a passive spring but also actively counteracts vibrations.

[0026] The vibration isolation system according to the invention comprises a plurality of actuators by means of which vibrations are actively counteracted by generating forces acting on the vibration-isolated load.

[0027] The actuators can be designed in particular as magnetic actuators and / or as pneumatic actuators.

[0028] According to the invention, each isolator comprises its own control unit with a digital-to-analog converter for controlling the actuators of the respective isolator. Furthermore, the control units of the isolators are connected serially to a bus system.

[0029] According to the invention, each insulator itself comprises a control unit with a processor unit on which a program runs to calculate control signals for generating active counterforces via the actuators based on sensor signals.

[0030] The calculated control signal is converted into a current, for example, via a digital-to-analog converter in order to control a magnetic actuator.

[0031] This can significantly reduce the amount of cabling required.

[0032] In a first embodiment of the invention, the control units of the insulators are connected to a central control unit, via which control signals are transmitted to the control units of the insulators.

[0033] Control signals are signals used to control actuators based on sensor signals and to generate counterforces.

[0034] This first embodiment of the invention therefore provides, in addition to the decentralized control units arranged in the insulators, a connected control unit which itself calculates control signals and forwards them to the control units in the insulators.

[0035] This embodiment of the invention has the advantage that the sensor signals from all insulators can be processed in the central control unit in order to generate control signals from them.

[0036] Because the central control unit only forwards control signals, preferably in digital form, to the isolators, the wiring effort is reduced. In particular, it is sufficient for the central control unit to be connected to the control units of the isolators via a bus.

[0037] In a second embodiment of the invention, the stationary vibration isolation system is designed such that the control units of the isolators control the actuators independently of a central control unit.

[0038] In this embodiment of the invention, a central control unit can be completely dispensed with.

[0039] Preferably, in this embodiment of the invention, the individual insulators are interconnected, in particular via a bus system. This enables the respective control unit of the insulator to take the sensor signals of the other insulators into account.

[0040] In this way, the individual, decentrally distributed control units of the isolators can generate coordinated control signals with which the actuators are controlled.

[0041] Instead of or in addition to a central control unit, in one embodiment of the invention the control units of the insulators can also be connected to a central configuration and / or diagnostic unit via a bus system.

[0042] The connected configuration and / or diagnostic unit does not participate in the calculation of control signals, but is designed to monitor the function of the individual control units, for example, to generate an error message in case of a fault. Furthermore, data can also be sent to the individual decentralized control units via the configuration and diagnostic unit, for example, to adapt the calculation routines of the decentralized control unit to the respective configuration of the vibration isolation system.

[0043] The control units of the isolators are connected serially to the bus system. Therefore, it is only necessary to run a single bus line from one isolator to the next.

[0044] In a preferred embodiment of the invention, the bus system is designed as a real-time Ethernet-capable bus system.

[0045] The use of a real-time Ethernet-enabled bus system makes it easy for the decentralized control units to also take into account the sensor signals of the other isolators.

[0046] For example, a bus system according to the IEC 61158-1:2014 standard (EtherCAT) can be used as a real-time Ethernet-capable bus system.

[0047] Preferably, the control units of the insulators themselves also each include an analog-to-digital converter, by means of which a sensor signal is processed.

[0048] Sensors, actuators and control units are therefore part of the insulator itself.

[0049] It is specifically intended that each insulator includes at least one spring, a plurality of sensors and actuators, and a control unit for their control.

[0050] The insulator only needs to be connected to a power supply and preferably also to a bus system.

[0051] Once the insulators are mechanically connected to the vibration-isolated load, they can be used directly without any further wiring.

[0052] Preferably, compensating forces in at least two, and especially preferably at least three, degrees of freedom are generated via the actuators in the insulator.

[0053] The invention relates in particular to a vibration isolation system in which actuators are arranged in the isolators, via which compensation forces are generated in three translational degrees of freedom and / or in three rotational degrees of freedom.

[0054] The vibration isolation system according to the invention is preferably designed such that the number of isolators is not limited by a central control unit.

[0055] In particular, the invention enables the connection of more than four, especially preferably more than six, insulators.

[0056] In a further development of the invention, the insulators comprise a pneumatic spring, wherein the pneumatic spring is actively controlled via the control unit of the insulator.

[0057] In this embodiment of the invention, the pneumatic spring is actively integrated into the vibration isolation control loop. For this purpose, the pneumatic spring includes a valve which is controlled by the isolator's control unit to regulate the pressure within the pneumatic spring. This active control of the pneumatic spring can serve both for height adjustment and for the active reduction of vibrations propagating into the system or emanating from the vibration-isolated load.

[0058] The invention further relates to a method for controlling an active stationary vibration isolation system, in particular a vibration isolation system as described above.

[0059] In this process, a vibration-isolated load is supported via a plurality of insulators, and vibrations are actively counteracted via a plurality of actuators.

[0060] According to the invention, the actuators are controlled via a separate control unit of the insulators.

[0061] The isolators thus provide active vibration isolation, preferably based on the sensor signals, independent of external control signals.

[0062] In one embodiment of the invention, the respective control unit can, however, take into account the sensor signals of the other insulators, especially if these are connected by means of a bus system. Brief description of the drawings

[0063] The subject matter of the invention will below be described with reference to schematically illustrated embodiments shown in the drawings. Figs. 1 to 7 will be explained in more detail. Fig. 1 The schematic diagram shows the basic structure of a stationary vibration isolation system known from the prior art. Fig. 2 shows a first embodiment of the invention in which the control units of the insulators are connected to a central control unit. Fig. 3 Figure 1 shows an embodiment in which the isolators are connected only to a configuration and / or diagnostic unit. Referring to Fig. 5 and Fig. 6 The simple scalability of the vibration isolation systems according to the invention will be explained in more detail. Fig. 6 is a schematic view of an insulator according to the invention. Fig. 7is a flowchart of the process steps according to an embodiment of the invention. Detailed description of the drawings

[0064] Fig. 1 Figure 1 shows a schematic view of the basic structure of a vibration isolation system known from the prior art.

[0065] The vibration isolation system 1 comprises a plurality of insulators 2a - 2d, which include a spring and support a vibration-isolated load 4.

[0066] The vibration-isolated load 4 can, for example, comprise a plate on which a machine for processing semiconductor components (not shown) is mounted in a vibration-isolated manner.

[0067] Each of the isolators 2a - 2d comprises actuators 5a - 5d and sensors 6a - 6d. The sensors 6a - 6d detect vibrations of the vibration-isolated load 4 and / or the base of the isolator coupled to the ground.

[0068] The sensors are connected to a central control unit 3.

[0069] Based on the signals from sensors 6a - 6d, the control unit calculates 3 compensation signals to control the actuators 5a - 5d.

[0070] This results in a star-shaped connection of the sensors 6a - 6d and actuators 5a - 5d to the control unit 3.

[0071] This results in complex wiring, especially since the sensors 6a - 6d usually provide an analog signal and the actuators 5a - 5d are controlled with an analog signal.

[0072] The control unit is therefore not only connected to the insulators 2a to 2d via data transmission lines, but lines must be laid over which sometimes high currents are transmitted to control the actuators 5a to 5d.

[0073] Fig. 2Figure 1 shows a vibration isolation system 1 according to the invention in a first embodiment. According to the invention, each isolator 2a - 2d comprises its own control unit 8a - 8d.

[0074] The data from sensors 6a - 6d are collected, digitized and at least pre-processed via the control units 8a - 8d.

[0075] In this embodiment, the insulators 2a - 2d are connected to a central control unit 3 via a bus system 7.

[0076] The central control unit 3 collects the data from the insulators 2a - 2d and calculates, based on the control parameters calculated by the decentralized control units 8a - 8d via the sensors 6a - 6d and actuators 5a - 5d, setpoints for the actuators 5a - 5d.

[0077] These setpoint values ​​are transmitted via the bus system 7 to the control units 8a - 8d of the individual insulators 2a - 2d.

[0078] The use of bus system 7 reduces the wiring effort. Only one bus cable and one power supply are required for each insulator 2a - 2d.

[0079] In this embodiment, the control parameters are set in the central control unit 3. The sensor data are transmitted from the isolators 2a - 2d to the central control unit 3. In the central control unit 3, the data are evaluated and the setpoints for the actuators 5a - 5d are calculated.

[0080] Since each isolator 2a - 2d includes its own control unit 8a - 8d, it is possible to outsource calculation operations from the central control unit 3 and / or to send the sensor data pre-filtered to the central control unit 3.

[0081] Fig. 3 shows an alternative embodiment of the invention.

[0082] According to the in Fig. 3In the illustrated embodiment, the sensor data are processed directly in the control units 8a - 8d of the insulators 2a - 2d.

[0083] Each isolator 2a - 2d has its own control parameters, which are used to control the actuators 5a - 5d.

[0084] A central control unit, as in the embodiment shown in Fig. 2 , is therefore not necessary.

[0085] In this embodiment, the insulators 2a - 2d or the control units 8a - 8d of the insulators 2a - 2d are connected via a bus system 7 to a configuration and / or diagnostic unit 9.

[0086] Data can be exchanged with control units 8a - 8d via the configuration and / or diagnostic unit 9. However, the configuration and / or diagnostic unit 9 does not calculate control values ​​for the actuators 5a - 5d based on the sensor signals, but serves solely to upload data for configuration and / or fault detection.

[0087] As in Fig. 4 As illustrated, the invention enables simple scalability of the vibration isolation system 1 with respect to the number of insulators 2a - 2n.

[0088] The insulators 2a - 2n are connected serially to a bus system 7.

[0089] No individual cables are required for each sensor and actuator radiating from the central control unit 4.

[0090] Otherwise, the embodiment corresponds to Fig. 4 according to the exemplary embodiment Fig. 2 .

[0091] It therefore refers to the embodiment of the invention in which, despite the decentralized control units 8a - 8n assigned to the insulators 2a - 2n, an additional central control unit 4 is provided.

[0092] Since the central control unit 4 is only connected to the bus system 7, it can be integrated into the active vibration isolation regardless of the number of insulators 2a - 2n.

[0093] The number of isolators 2a - 2n is therefore limited at most by the maximum data transmission rate of the bus system 7, which is usually so high that it does not play a role in determining the practically useful number of isolators 2a- 2n.

[0094] As in Fig. 5As shown, this also applies to a vibration isolation system 1 in which the insulators 2a - 2n are not connected to a central control unit, but, in this embodiment, only to a configuration / diagnostic unit 9.

[0095] Fig. 6 schematically shows the structure of an insulator 2, as it is used particularly for the in Figs. 2 to 5 The vibration isolation system shown can be used.

[0096] The insulator 2 comprises a spring 10, which in this embodiment is designed as a pneumatic spring.

[0097] The spring is effective in both horizontal and vertical directions and supports the vibration-isolated load 4 on the insulator 2.

[0098] The insulator 2 also includes the actuators 5', 5" and 5‴.

[0099] In this schematic representation, translational compensation forces are generated via actuators 5' and 5" and rotational compensation forces via actuator 5‴.

[0100] The insulator 2 includes its own control unit 8, via which actuators 5' - 5‴ are controlled.

[0101] The control unit 8 processes sensor signals for this purpose.

[0102] In this embodiment, at least one sensor 6' is provided, which detects vibrations of the vibration-isolated load 4, and at least one further sensor 6'', which detects vibrations of the base, i.e., vibrations propagating from the ground. The direction of action of the sensors 6', 6'' is not shown in this schematic representation. It is understood that preferably different sensors are used for different degrees of freedom, corresponding to the actuators 5' - 5‴ for different degrees of freedom.

[0103] Based on the signals from sensors 6' and 6" the control unit controls the actuators 5' - 5‴ to reduce vibrations by generating counterforces.

[0104] Specifically, the control unit 8 includes an analog-to-digital converter 11, which converts the analog sensor signal into a digital signal that is then forwarded to a processor unit 12 of the control unit, on which a program runs. It is understood that the analog-to-digital converter 11 can be located at any point within the insulator 2, for example, in the control unit 8 or even in the sensor 6', 6" itself.

[0105] A digital control signal is generated via the processor unit 12, which is forwarded to a digital-to-analog converter 13.

[0106] The digital-to-analog converter 13 controls the actuators 5' to 5‴, which are preferably designed as magnetic actuators, for active vibration isolation by generating currents from the digital control signals, which the magnetic actuator uses to generate counterforces. It is understood that the digital-to-analog converter 13 can also be arranged at any point on the isolator 2.

[0107] In this embodiment, the spring 10 is also integrated into the active vibration isolation.

[0108] An analog control signal for a valve is also generated via a digital-to-analog converter 13, which regulates the pressure in the spring 10.

[0109] The isolator 2 includes the bus connection 14, by means of which it is connected to a bus system 7. Via the bus system 7, the isolator 2, or rather the control unit 8 of the isolator 2, can communicate with other isolators and / or with a central control unit and / or with a configuration and / or diagnostic unit.

[0110] Otherwise, the insulator 2 only requires a power supply (not shown).

[0111] Fig. 7 is a schematic flowchart of the basic principle of the method according to the invention.

[0112] Vibrations are detected using sensors.

[0113] The actuators of the isolators are controlled by the integrated control unit based on the signal from the sensors, which is processed in a control unit integrated into an isolator.

[0114] Optionally, control signals can be generated via a higher-level central control unit.

[0115] The invention made it possible to easily reduce the installation effort of an active vibration isolation system while simultaneously increasing scalability with regard to the number of isolators. Reference symbol list

[0116] 1 Vibration isolation system 2, 2a-2n Isolator 3 Central control unit 4 Isolated load 5, 5a-5n Actuator 6, 6a-6n Sensor 7 Bus system 8, 8a-8n Control unit of an isolator 9 Configuration / diagnostic unit 10 Spring 11 Analog-to-digital converter 12 Processor unit 13 Digital-to-analog converter 14 Bus connection

Claims

1. Stationary vibration isolation system (1) comprising a plurality of isolators (2, 2a-2n) by means of which a load (4) which is mounted in a vibration isolated manner is supported, wherein the vibration isolation system (1) comprises a plurality of actuators (5, 5a-5n) by means of which vibrations are actively countered, wherein each isolator comprises its own control unit, characterized in that the control units of the isolators (2, 2a-2n) each comprise a digital-analog converter for control of the actuators (5, 5a-5n), wherein the control units (8, 8a-8n) of the isolators (2, 2a-2n) are connected in-series with the bus system.

2. Stationary vibration isolation system (1) according to claim 1, wherein the control units (8, 8a-8n) of the isolators (2, 2a-2n) are connected with a central control unit (3) via which the control signals are transmitted to the control units (8, 8a-8n) of the isolators (2, 2a-2n).

3. Stationary vibration isolation system (1) according to claim 1, wherein the control units (8, 8a-8n) of the isolators (2, 2a-2n) control the actuators, independently of a center control unit (3).

4. Stationary vibration isolation system (1) according to one of the preceding claims, wherein the control units (8, 8a-8n) of the isolators (2, 2a-2n) are connected via a bus system (7) with one another and / or with a central control unit (3) and / or with a central configuration and / or diagnostic unit.

5. Stationary vibration isolation system (1) according to one of the two preceding claims, wherein the bus system (7) is designed as a real time ethernet capable bus system, in particular according to IEC 61158-1:2014.

6. Stationary vibration isolation system (1) according to one of the two preceding claims, wherein the control units (8, 8a-8n) of the isolators (2, 2a-2n) each comprise an analog-digital converter (11) by means of means of which a sensor signal is processed.

7. Stationary vibration isolation system (1) according to one of the preceding claims, wherein the actuators (5, 5a-5n) and / or sensors (6, 6a-6n) are integrated into the isolators (2, 2a-2n).

8. Stationary vibration isolation system (1) according to one of the preceding claims, wherein via the actuators (5, 5a-5n) compensating forces are generated in at least two, preferably at least three degrees of freedom, in particular wherein via the actuators (5, 5a-5n) compensation forces are generated in three translational degrees of freedom and / or in three rotational degrees of freedom.

9. Stationary vibration isolation system (1) according to one of the preceding claims, wherein vibration isolation system comprises a machine, mounted in a vibration isolated manner, for processing, in particular for machining or measuring of semiconductor components and / or of nanostructured elements, and / or laboratory equipment, medical device, in particular an magnetic resonance scanner.

10. Stationary vibration isolation system (1) according to one of the preceding claims, characterized in that the vibration isolation system is designed such a way that the number of isolators (2, 2a-2n) is not limited by a central control unit (3).

11. Stationary vibration isolation system (1) according to one of the preceding claims, wherein each respective isolator (2, 2a-2n) includes a pneumatic spring, wherein the pneumatic spring is actively controlled via the control unit of the isolator (2, 2a-2n).

12. Method for controlling an active stationary vibration isolation system (1) according to one of the preceding claims, wherein a load (4) which is mounted in a vibration isolated manner is supported by a plurality of isolators (2, 2a-2n) and vibrations are actively countered via a plurality of actuators (5, 5a-5n), wherein the actuators (5, 5a-5n) are each controlled by a separate control unit of the isolators (2, 2a-2n), characterized in that, the control units of the isolators (2, 2a-2n) are connected in-series with the bus system.

13. Method according to the preceding claim, whereby active vibration isolation is provided via the isolators (2, 2a-2n) based on sensor signals, independently of external control signals.