Electromagnetic support with position-independent characteristics
    1.
    发明授权
    Electromagnetic support with position-independent characteristics 失效
    具有位置独立特性的电磁支持

    公开(公告)号:US5227948A

    公开(公告)日:1993-07-13

    申请号:US664162

    申请日:1991-03-04

    IPC分类号: G05D3/00 F16C39/06 H01F7/20

    摘要: A device for positioning a body (5) by means of at least two electromagnets (13, 15). A position sensor (29) measures the size of an air gap (23) between one of the electromagnets (13, 15) and a guide beam (1). An output signal of the position sensor (29) is applied to an electronic control unit (35) which passes a control current through the electromagnets (13, 15) in dependence on a difference between the measured and a desired size of the air gap (23). An electronic multiplier (47, 59) is connected between the control unit (35) and each of the electromagnets (13, 15), multiplying a control signal from the control unit (35) by the output signal from the position sensor (29). In this way a force exerted by the electromagnets (13, 15) on the guide beam (1) depends exclusively on the value of the control signal and not on the size of the air gap (23), so that a position-independent control is obtained. Such an accurate position-independent control may be used in an optical lithographic device for the irradiation of semiconductor substrates. Alternatively, such an electromagnetic support with a position-independent control may be constructed so as to form a micromanipulator.

    Electromagnetic support with current-independent characteristics
    2.
    发明授权
    Electromagnetic support with current-independent characteristics 失效
    具有电流独立特性的电磁支持

    公开(公告)号:US5243491A

    公开(公告)日:1993-09-07

    申请号:US664075

    申请日:1991-03-04

    IPC分类号: G05D3/00 F16C39/06 H01F7/20

    CPC分类号: F16C32/0446 F16C32/0451

    摘要: A device for positioning a body (5) by means of at least two electromagnets (13, 15). A position sensor (29) measures the size of an air gap (23) between one of the electromagnets (13, 15) and a guide beam (1). An output signal of the position sensor (29) is applied to a linear electronic control unit (35) which passes a control current through the electromagnets (13, 15) in dependence on a difference between the measured and a desired size of the air gap (23). An electronic root extractor (37) is connected between the control unit (35) and the two electromagnets (13, 15). An output signal of the root extractor (37) has a value equal to the square root of a control signal coming from the control unit (35). In this way a force exerted by the electromagnets (13, 15) on the guide beam (1) is proportional to the value of the control signal, so that a control is obtained with the linear control unit ( 35) in which the stiffness and bandwidth are independent of the value of the control current.Since the electrical resistance losses in the electromagnets (13, 15) in such a device are low, the device is particularly suitable for use as an electromagnetic bearing in an optical lithographical device for the irradiation of semiconductor substrates, or in other precision machines.

    Optical lithographic device having a machine frame with force
compensation
    3.
    发明授权
    Optical lithographic device having a machine frame with force compensation 失效
    具有强制补偿功能的机器框架的光学地平面设备

    公开(公告)号:US5172160A

    公开(公告)日:1992-12-15

    申请号:US784286

    申请日:1991-10-29

    摘要: An optical lithographic device having a machine frame (1) to which is fastened a lens system (11) having a vertical optical main axis (13). Below the lens system (11), a positioning device (35) is fastened on a support member (3) of the machine frame (1), by means of which device an object table (27) is displaceable relative to the lens system (11) over a guide surface (5) of the support member (3) extending perpendicular to the optical main axis (13).The device is provided with a force actuator system (67) fastened to a reference frame (83) and controlled by a feedforward control system (95). The force actuator system (67) exerts a compensatory force on the support member (3) with a direction opposite to a direction of a reaction force simultaneously exerted by the positioning device (35) on the support member (3), and with a value which is substantially equal to a value of the said reaction force. The control system (95) further comprises a negative acceleration feedback (107), whereby the force actuator system (67) exerts a control force on the support member (3) which is determined by an acceleration of the support member (3) measured by an acceleration transducer (111, 113, 115). The use of the force actuator system (67) prevents undesirable movements of the support member (3) under the influence of a reaction force exerted by the positioning device (35) on the support member (3) and under the influence of external forces.The optical lithographic device can be used inter alia for illuminating semiconductor substrates, where a semiconductor pattern provided on a mask (17) is imaged on a semiconductor substrate (25), which is positioned on the object table (27), by means of the lens system (11).

    Electromagnetic support with unilateral control currents
    4.
    发明授权
    Electromagnetic support with unilateral control currents 失效
    具有单向控制电流的电磁支持

    公开(公告)号:US5264982A

    公开(公告)日:1993-11-23

    申请号:US664074

    申请日:1991-03-04

    CPC分类号: F16C32/0451

    摘要: A device for positioning a body (5) by means of at least one pair of electromagnets (13, 15). A position sensor (29) measures the size of an air gap (23) between one of the electromagnets (13, 15) and a guide beam (1). An output signal of the position sensor (29) is applied to an electronic control unit (35) which passes a control current through the electromagnets (13, 15) in dependence on a difference between the measured and a desired size of the air gap (23). In one embodiment an electrical switch (53) is connected between the control unit (35) and the two electromagnets (13, 15) controlled by the control unit (35), applying the control current to only one of the two electromagnets (13, 15) in dependence on the polarity of a control signal from the control unit (35). The use of the switch insures that the control current flows through only one of the two electromagnets at a time so that in a simple manner a difference necessary for supporting the body is achieved between the forces exerted on the guide beam (1) by the electromagnets (13, 15). the electrical resistance losses in the electromagnets (13, 15) in such a device are low, the device is eminently suitable for use as an electromagnetic bearing in an optical lithographical device for the irradiation of semiconductor substrates, or in other precision machines.