JP4067053B2 - Capacitance sensor type measuring device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for measuring the position, shape, and the like of a target using a capacitance sensor. The measuring apparatus is suitably applied to an exposure system for transferring an original pattern such as a mask or a reticle onto a substrate or a three-dimensional object such as a semiconductor wafer or a glass plate, and a processing system or a processing system for a semiconductor process. .
[0002]
[Prior art]
One method for accurately measuring the position and shape of a sample (target) is to use a capacitance sensor. This method measures the distance between the sensor probe and the target by detecting the magnitude of the capacitance generated between the sensor probe and the target. The capacitance is detected as an AC impedance. Specifically, in many cases, a weak alternating current supplied from a sensor amplifier is supplied from a sensor probe toward a target, and a voltage drop due to the impedance is measured. The current that flows from the sensor probe to the target is returned to the other terminal of the sensor amplifier through a conductor that is generally at the same potential as the chassis ground of the system. Usually, since the measured capacitance is a small value on the order of pF, it is easily affected by stray capacitance. Therefore, in mounting from the sensor amplifier to the sensor probe and mounting of the ground line from the target, the potential is usually set so that the influence of stray capacitance is reduced.
[0003]
Ideally, a capacitive sensor is used by coupling a target having a sufficiently low impedance to ground with a low impedance. For this reason, a structure in which the mounting base on which the target is placed is made of a conductor and the mounting base is connected to the ground is often used.
[0004]
FIGS. 15A and 15B are configuration diagrams of a conventional measuring apparatus using a capacitance sensor, where FIG. 15A is an overall configuration diagram, and FIG. 15B is a side view of a main part. A fixed capacitance sensor is provided, and a plurality of measurement points are sequentially measured by moving a stage on which a target is mounted. In the figure, 120a and 120b are first and second sensor probes, 121a and 121b are first and second sensor amplifiers, 122 is a target, 123 is a sensor cable, 124 is a controller, 125 is a metal chuck, and 127 is a constant. A panel (insulating mounting base) 128 indicates an oscillator.
[0005]
[Problems to be solved by the invention]
When the measurement target of the electrostatic sensor is a semiconductor or the like, it has a somewhat large internal impedance. Furthermore, there may be a case where it cannot be coupled to ground with a low impedance. In such a case, the alternating currents flowing out from a plurality of sensor probes flow into the target internal impedance and the ground impedance, which are common impedances. Therefore, each sensor (sensor is a sensor amplifier and sensor) due to a voltage drop in that portion. Error).
[0006]
In FIG. 16, since Z3 and Z4 are common impedances for a plurality of sensors, the voltage drop due to the sensor current appears as a measurement error because the first sensor and the second sensor interfere with each other.
[0007]
A measurement error caused by the sensor drive phase and the ground impedance of the conventional measurement apparatus will be described with reference to FIG. Since the drive current phases of the first sensor probe and the second sensor probe are the same, the sum of both currents flows through the common impedance as a ground current, resulting in a voltage drop. This voltage drop appears as it is between the terminals of the sensor amplifiers 121a and 121b (between S101 and S102 and between S201 and S202) and becomes a measurement error of each sensor.
[0008]
It is an object of the present invention to prevent measurement errors caused by common impedance in a measurement apparatus including a plurality of capacitance sensors or due to interference between sensors due to an electrostatic field.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, a measuring device of the present invention is a device that measures the distance between a sensor probe and a target to be measured using a capacitance sensor, A mounting table for mounting the target; and a probe holding member for holding the sensor probe. A plurality of sensor probes; and a sensor amplifier connected to the sensor probes and outputting a measurement result thereof; and a sensor amplifier including the sensor probes between a first terminal and a second terminal provided in the sensor amplifier. An AC electrical signal supplied from the sensor amplifier to the sensor probe when a measurement system circuit is connected and the distance between the sensor probe and the target to be measured is measured. Of at least two sensor probes among the plurality of sensor probes. It is characterized by
Furthermore, the measurement device of the present invention is a device that measures the distance between the sensor probe and the target to be measured using a capacitance sensor, and includes a mounting base on which the target is mounted and a probe holder that holds the sensor probe. A plurality of sensor probes, and a sensor amplifier that is connected to the sensor probes and outputs a measurement result thereof, and the sensor between the first terminal and the second terminal provided in the sensor amplifier. When measuring the distance between the sensor probe and the target to be measured by connecting a circuit of the system to be measured including the probe, the phase of the AC electric signal supplied from the sensor amplifier to the sensor probe is determined by the plurality of sensor probes. 120 degree difference between at least three of the sensor probes .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the present invention is an apparatus for measuring a distance between a sensor probe and a target to be measured using a capacitance sensor, wherein the first sensor probe, the second sensor probe, and the target are A mounting base to be mounted; a probe holding member that holds the sensor probe; and a sensor amplifier that is connected to the sensor probe and outputs a measurement result, the sensor amplifier having a first terminal and a second terminal, In a measuring device in which an electrode of the sensor probe is connected to a first terminal and a closed circuit of a system to be measured including the sensor probe is connected between the first terminal and the second terminal, the sensor amplifier supplies the sensor probe The phase and / or current amplitude value of the AC electrical signal is made different between the first sensor probe and the second sensor probe.
[0011]
【Example】
Examples of the present invention will be described below.
[First embodiment]
A semiconductor wafer position measuring apparatus according to a first embodiment of the present invention will be described with reference to FIG. 1A and 1B are configuration diagrams of a semiconductor wafer position measuring apparatus according to a first embodiment. FIG. 1A is an overall configuration diagram, and FIG.
[0012]
This apparatus measures the height and inclination of the surface of a semiconductor wafer vacuum-adsorbed on a SiC vacuum chuck using a fixed sensor probe.
[0013]
Here, the interval between the sensor probe and the target is referred to as a measurement gap (see FIG. 1B). Although the setting of the measurement gap differs depending on the type of sensor probe, in this embodiment, it is about 200 to 300 μm.
[0014]
The first and second sensor probes 10a and 10b have a three-layer structure coaxially from the center, that is, a center electrode, a guard electrode, and an external electrode. The electrode used for measurement is the center electrode, and is connected to the center electrode terminals (S101, S201) of the first and second sensor amplifiers 11a, 11b. A sine wave constant amplitude current of several tens of kHz is passed from the first and second sensor amplifiers to the center electrode. The current flows to the housing ground through the capacitively coupled target 12. The housing ground is connected to the ground terminals (S102, S202) of the first and second sensor amplifiers 11a, 11b. The first and second sensor amplifiers 11a and 11b detect the voltage between the center electrode terminals (S101 and S201) and the ground terminals (S102 and S202), thereby including the loop impedance including the capacitive impedance of the measurement gap. I understand. If the measurement gap is d and the effective facing area between the sensor probe and the target is A, the capacitance C of the measurement gap d is expressed by the following equation.
[0015]
C = εo · A / d
Here, εo is the dielectric constant in vacuum, and the dielectric constant in air is almost the same.
[0016]
If the angular frequency of alternating current flowing through the sensor probe is ω and the current value is i, the voltage value e between the center electrode terminal and the ground terminal is expressed by the following equation.
e = i / (ω · C)
[0017]
From both of the above formulas,
e = i · d / (ω · εo · A)
d = e · ω · εo · A / i
Is guided. If i, ω, and A do not change, d proportional to e is obtained.
[0018]
The guide electrode is provided to prevent the electric field emitted from the center electrode from spreading to the periphery. The guard electrode is connected to a guard electrode terminal (not shown) of the sensor amplifier. The guard electrode terminal outputs the same voltage as e (the same potential as the center electrode terminals S101 and S201). Driven by low output impedance driver. Further, a coaxial cable 13 is used for connection between the first and second sensor amplifiers 11a and 11b and the first and second sensor probes 10a and 10b. The guard electrode is connected. Thereby, the influence of the capacity | capacitance between two lines of the connection cable 13 is canceled.
[0019]
The first and second sensor amplifiers 11a and 11b drive the first and second sensor probes 10a and 10b and measure voltages. The measured voltage is A / D converted and transmitted to the controller 14. The controller 14 performs processing and display of measured values. At this time, correction such as offset, gain, and non-linearity may be performed inside the controller 14.
[0020]
The vacuum chuck 15 is made of SiC ceramics. This is to prevent deformation of the chuck due to temperature changes. The sensor holding frame 16 is attached to the chuck 15. Further, the chuck 15 is installed on a metal surface plate 17. Furthermore, the metal surface plate 17 is connected to the ground.
[0021]
Therefore, the coupling from the target 12 to the earth is performed by capacitive coupling using a capacitor in which the chuck 15 is sandwiched between the target 12 and the metal surface plate 17. This configuration is designed to satisfy the measurement accuracy when only one sensor is used. However, this capacitive coupling portion exists as a common impedance for the first sensor and the second sensor.
[0022]
In FIG. 1, the controller 14 presets the drive phase of each sensor with respect to a phase control apparatus. Further, the controller 14 receives measurement values from the first sensor amplifier 11a and the second sensor amplifier 11b and displays them externally.
[0023]
The phase controller 18 outputs a sensor drive timing signal and a sensor measurement timing signal to the first sensor amplifier 11a and the second sensor amplifier 11b. The sensor measurement timing signal is 2 kHz. In this embodiment, the sensor measurement timing signals of the first sensor and the second sensor are the same. The phase control device 18 also outputs a sensor measurement timing signal to the controller 14 to indicate the timing for taking in the measurement value.
[0024]
FIG. 2 is an equivalent circuit regarding the capacitance sensor of the present embodiment. Compared to the conventional example, the first and second sensor amplifiers 11a and 11b are characterized by having phase adjusting means.
[0025]
Hereinafter, the sensor drive phase and measurement accuracy of this embodiment will be described with reference to FIG. FIG. 3 is a diagram illustrating a drive current, a ground current, and a sensor measurement value for the sensor probe of the measurement apparatus according to the present embodiment.
[0026]
In this embodiment, the phase difference between the drive currents (weak currents for measurement) of the first sensor and the second sensor is set to 180 degrees. Thereby, the current flowing through the common impedance is canceled out. The ground current in FIG. 3 is not completely zero. This is a residue generated because the ground current of the first sensor and the ground current of the second sensor do not completely match. Although a measurement error of a value corresponding to the remainder occurs, the error can be significantly reduced as compared with the conventional example (see FIG. 17).
[0027]
Further, the phase between the sensors set by the controller 14 is not limited to 180 degrees and can be set arbitrarily. Therefore, it is possible to set the phase difference that provides the best measurement accuracy. For example, paying attention to the reproducibility of measurement, the controller 14 can determine the optimum phase by collecting data for the set phase.
[0028]
As another method, when the interference between sensors cannot be adjusted by the phase alone, it is possible to more accurately cancel the ground current by slightly increasing or decreasing the current value of each sensor. As a method, the ground current may be canceled by changing the current amplitude value, not the phase, between the sensors.
[0029]
Furthermore, in the present embodiment, the two first and second sensors measure the same target. However, even if a sensor that measures another target interferes with the present embodiment, Measurement accuracy can be improved by the same means.
[0030]
As described above, according to the first embodiment of the present invention, in a measuring apparatus using a plurality of capacitance sensors, it has been difficult to achieve high accuracy due to interference between sensors. On the other hand, the influence of interference can be reduced.
[0031]
[Second Embodiment]
As a second embodiment of the present invention, an X-ray stepper for transferring a mask pattern to a wafer by step and repeat will be described.
[0032]
FIG. 4 is a view showing a part of a proximity gap equal-magnification X-ray exposure apparatus using a synchrotron ring light source. Specifically, a part related to the capacitance sensor is shown in this exposure apparatus. In an actual apparatus, the part of FIG. 4 is placed in a sealed chamber and used in a 20 kPa high purity helium atmosphere.
[0033]
In this embodiment, exposure is performed while holding the mask 31 and the wafer 32 in a very small gap of 10 μm or less, so high accuracy is required for height measurement of the wafer 32 surface and the mask 31 surface. When the set gap is different from the assumed gap, the exposure result is seriously affected, such as deterioration of line width accuracy. Further, in order to realize high throughput, the wafer 32 is step-repeated while maintaining the exposure gap. In this case, if the parallelism between the mask 31 surface and the wafer 32 surface is poor, the exposure result may be deteriorated due to the deformation of the mask membrane, and the membrane may be destroyed.
[0034]
In this embodiment, the X-rays emitted from the synchrotron ring are introduced in the direction of the arrow shown. In accordance with this, the mask 31 and the wafer 32 are exposed while being held vertically.
[0035]
Each of the masks 31 includes a mask frame, a mask substrate, and a membrane (not shown). The mask frame is made of SiC and has a diameter of 125 mm. A 4-inch diameter mask substrate is bonded to the mask frame. A membrane and an absorber pattern are formed on the mask substrate. The mask substrate is back-etched at the exposure area.
[0036]
The mask 31 is chucked by the mask chuck 34 of FIG. The mask chuck 34 is mounted on a mask stage 35 and has a degree of freedom in the Z, θ, ωx, and ωy axes.
[0037]
In FIG. 4, a wafer 32 is vacuum-sucked by a wafer chuck 36 on a wafer stage 37 by a wafer transfer system (not shown). The wafer chuck 36 is made of SiC, and a large number of minute pins are provided on the chuck surface. The wafer chuck 36 is mounted on a SiC wafer stage 37. The wafer stage 37 is mounted on the X stage 38, and the X stage 38 is further mounted on the Y stage 39. The Y stage 39 is fastened on the surface plate 40. The surface plate 40 is installed on the floor 42 via a damper 41 that blocks floor vibration. The wafer stage 37 is driven by a linear motor or the like and has a degree of freedom in the X, Y, Z, θ, ωx, and ωy axes. The positions of the mask 31 and the wafer 32 are measured by an alignment measurement unit (not shown).
[0038]
Next, measurement by the capacitance sensor of the present embodiment will be described.
After the wafer 32 is chucked by the wafer chuck 36 of the wafer stage 37, the wafer stage 37 is driven to measure the 20 mm pitch lattice points on the wafer 32 with a capacitance sensor. In this embodiment, the target is a circular wafer 32 having a diameter of 200 mm. Ten electrostatic capacitance sensor probes 43 for wafer measurement are provided in the Y direction, and measurement is performed by driving the wafer stage 37 in the X direction so as to cover all the measurement points which are the lattice points. The Y coordinate at the time of measurement is determined at a determined coordinate. At the time of measurement, the wafer stage 37 does not necessarily need to be stopped, and the controller of the wafer stage 37 can manage the measurement timing with respect to the coordinates and perform measurement while driving.
[0039]
The wafer measurement capacitance sensor probe 43 is attached to a metal member (sensor probe attachment portion 45) that also serves as an opposing ground plate attached to the mask frame 33. The electrostatic capacitance sensor probe 44 for mask measurement is attached to a metal member (sensor probe attachment portion 46) that also serves as an opposing ground plate attached to the wafer stage 37. Both of these metal members 45 and 46 are connected to a ground terminal of a sensor amplifier (not shown) using a conductive wire. In addition, the area is increased within the range allowed by design so that sufficient capacitive coupling as an opposing ground plate can be obtained, and the respective targets are installed close to each other.
[0040]
In the substrate supported by the insulator as in this embodiment, it is difficult to ground the substrate without mechanical influence, and the earth impedance tends to be high. In that case, it becomes particularly easy to receive interference from other sensors. Therefore, ground plates 46 and 45 facing the respective targets 31 and 32 are provided to lower the ground impedance by capacitive coupling.
[0041]
Hereinafter, the control block of the present embodiment will be described with reference to FIG. FIG. 5 is a block diagram of the X-ray exposure apparatus according to the present embodiment.
[0042]
The console 50 controls the entire sequence of the exposure apparatus and provides a user interface and a network interface. The stage CPU 51 receives commands on the sequence from the console 50 and performs unit control of the wafer stage and the mask stage. In addition to this, the exposure apparatus includes an alignment unit, a transport unit, an illumination unit, etc. (not shown), and each unit is controlled by a separate CPU. The stage DSP 52 manages drive control and positioning control of the wafer stage and mask stage. Digital control is performed using a DSP capable of high-speed computation. The stage DSP 52 also captures the sensor drive phase command, the measurement timing command, and the measurement value of the capacitance sensor, which is the main point of the present embodiment. The sensor I / F 56 outputs drive signals to the sensor amplifiers of the first to tenth wafer electrostatic sensor amplifiers 57a to 57j and the mask electrostatic sensor amplifier 58 in accordance with the sensor drive phase command received from the stage DSP 52. Further, a measurement timing command is transmitted to each of the electrostatic sensor amplifiers 57a to 57j, 58. The electrostatic sensor amplifiers 57a to 57j and 58 control the supply current to the first to tenth wafer sensor probes 59a to 59j and the mask sensor probe 60 according to the sensor drive signal. Further, according to the sensor measurement timing signal, the measurement value is taken in and output to the sensor I / F 56.
[0043]
FIG. 6 shows an equivalent circuit relating to the capacitance sensor of this embodiment. Reference numerals 601 to 610 denote sensor amplifiers (ten) corresponding to the first to tenth wafer measurement sensors. Reference numeral 611 denotes a sensor amplifier for a mask measurement sensor. Cw1 to Cw10 are capacitances of measurement gaps corresponding to the first to tenth wafer measurement sensors. Cm is the capacitance of the measurement gap for the mask measurement sensor. Among the wafer internal impedances, Zw1 to Zw10 are independent terms and Zw11 is a common term for each wafer sensor. Zw12 is a common term for each wafer sensor outside the wafer. The impedance due to the wafer chuck, the wafer stage portion, and other capacitive coupling corresponds to Zw12. Zm is an independent term for the mask sensor, and Z13 is a term common to all the sensors. Z13 is an almost negligible value. The most problematic is Zw12. Zw12 makes it easy for the first to tenth wafer sensors to interfere with each other.
7 and 8 show the relationship between the stage position and measurement.
[0044]
Next, the relationship between measurement phases will be described with reference to FIGS.
FIG. 9 shows the drive current when all the sensors are used in the same phase in the configuration of this embodiment as in the conventional example. In the measurement result in this case, as shown in FIGS. 10 and 11, interference between the sensors appears as much as the ground current changes depending on the number of sensors facing the wafer.
[0045]
On the other hand, in the configuration of the present embodiment, when each sensor is driven at the phase shown in FIG. 12, the ground current can always be canceled. In the sensor drive current phase shown in FIG. 12, two sensors arranged symmetrically with respect to a line parallel to the X axis passing through the center of the wafer are considered as a pair, and the current of each pair is reversed. As a result, the ground current is substantially constant regardless of the number of sensors facing the wafer. 13 and 14 show the measurement results in this case. The reason why a slight error occurs in the measured values in FIGS. 13 and 14 is that the sensor currents of the respective pairs are not completely cancelled. This is due to the fact that the sensor current amplitudes do not match and the phase is not completely different by 180 degrees. Since both are problems in mounting, it is possible to further reduce errors.
[0046]
In the present embodiment, the fifth and sixth sensors having the longest measurement length are most susceptible to the influence of other sensors. When other sensors pass through the wafer boundary, the measurement value may be suddenly disturbed. In order to reduce such measurement errors that are difficult to correct, it is effective that the stage DSP 52 of FIG. 5 has the following phase setting means. That is, paying attention to the measured value of the sensor (referred to as sensor A) in which the measurement error is the most problematic, it is estimated which sensor interference causes the above-described sudden disturbance. Specifically, it is estimated that the influence is from the stage coordinates where the measurement value is disturbed, or from the sensor (referred to as sensor B) that has passed the wafer boundary at the time. Next, the phase of the sensor B is slightly changed and the measurement is performed again to find a condition for improving the measurement result of the sensor A. If there are other sensors whose measurement error is a problem under the conditions, the conditions are similarly determined to find a condition in which all sensor accuracy satisfies the requirement.
[0047]
In this embodiment, the sensor is fixed and each point on the wafer is measured by driving the wafer stage. For the purpose of the present invention, a sensor is mounted on a movable mechanism, and the sensor is moved, or each sensor on the wafer is measured by changing the relative position by moving the sensor and the wafer relative to each other. The same purpose can be achieved by measuring points.
[0048]
In this embodiment, the number of sensors that simultaneously pass through the wafer boundary is two. However, for example, in the case of three, it is also effective to set the phase difference to 120 degrees. In addition, the phase or / and current amplitude value of the AC current signal supplied to a plurality of sensor probes simultaneously located with respect to the target boundary is generated in other sensors when the plurality of sensor probes pass through the target boundary. It is preferable to determine so that the change in the measured value is minimized.
[0049]
Furthermore, the controller in the present embodiment determines the phase or / and current amplitude value of the alternating current signal supplied to each sensor probe according to the arrangement of each sensor probe, the shape of the target, the target stage or / and the position coordinate of the probe stage. It is possible.
[0050]
As described above, according to the second embodiment of the present invention, in the system in which the target and the capacitance sensor are relatively moved and measured, the measurement is efficiently performed according to the position coordinates and / or the moving speed. It can be carried out.
[0051]
Note that the measurement apparatus in the first and second embodiments described above can be used in a device manufacturing apparatus such as a semiconductor manufacturing apparatus or an exposure apparatus, using a target to be measured as a semiconductor wafer or a transfer master.
[0052]
Embodiment
Examples of embodiments of the present invention are listed below.
[Embodiment 1] An apparatus for measuring a distance between a sensor probe and a target to be measured using a capacitance sensor, wherein a plurality of sensor probes are connected to the sensor probe and a measurement result is output. A first terminal and a second terminal provided in the sensor amplifier, the electrode of the sensor probe is connected to the first terminal, and the ground is connected to the second terminal, and the first terminal and When forming a closed circuit of the measurement target system including the sensor probe between the second terminals and measuring the distance between the sensor probe and the measurement target, an AC electric signal supplied from the sensor amplifier to the sensor probe is A measuring device that varies between at least two of the plurality of sensor probes.
[Embodiment 2] The measurement apparatus according to Embodiment 1, comprising a mounting base on which the target is mounted and a probe holding member that holds the sensor probe, and the phase or / and current amplitude value of the alternating current signal A measuring device for differentiating at least two of the plurality of sensor probes.
[Embodiment 3] In the measurement apparatus according to Embodiment 2, the phase or / and current amplitude value of the AC electric signal is a phase or / and current that minimizes a measurement value error due to interference between sensors. A measuring device that is an amplitude value.
[0053]
[Embodiment 4] In the measurement apparatus according to Embodiment 2, the phase or / and current amplitude value of the AC electrical signal is the phase or / and current amplitude value that provides the best reproducibility under the same conditions. Is a measuring device.
[Embodiment 5] The measuring apparatus according to any one of Embodiments 1 to 4, wherein all or some of the plurality of sensor probes measure the same target.
[Embodiment 6] The measuring apparatus according to any one of Embodiments 1 to 4, wherein each of the plurality of sensor probes measures different targets.
[Embodiment 7] In the measurement apparatus according to any one of Embodiments 1 to 6, the measurement target is mounted on a movable target stage, and includes a target stage control unit that drives and controls the target stage. , Measuring device.
[Embodiment 8] In the measurement apparatus according to any one of Embodiments 1 to 6, the plurality of sensor probes are mounted on a movable probe stage, and a probe stage controller that drives and controls the probe stage is provided. A measuring device.
[Embodiment 9] The measurement apparatus according to any one of Embodiments 1 to 8, wherein measurement is performed while changing a relative position between the sensor probe and the target.
[0054]
[Embodiment 10] In the measurement apparatus according to any one of Embodiments 1 to 9, each probe is arranged according to the arrangement of each sensor probe, the target shape, the target stage or / and the position coordinates of the probe stage. A measurement device further comprising a measurement controller that determines a phase or / and a current amplitude value of an AC electric signal to be supplied.
[Embodiment 11] In the measurement apparatus according to any one of Embodiments 1 to 10, a center of a plurality of sensor probes is located relative to a target boundary with respect to a relative position change between the sensor probe and the target. A measuring device that arranges sensor probes so that they are positioned simultaneously.
[Embodiment 12] In the measurement apparatus according to Embodiment 11, the phase or / and current amplitude value of the AC electrical signals of the plurality of sensor probes that are simultaneously positioned with respect to the target boundary are determined by the plurality of sensor probes at the target boundary. A measurement device that determines that the change in measurement value caused by other sensors is minimized by passing the sensor.
[Embodiment 13] In the measurement apparatus according to Embodiment 11 or 12, the measurement apparatus includes two sensor probes that are simultaneously positioned with respect to the boundary of the target, and the electric signal phases of the two sensor probes are different by 180 degrees. Measuring device.
[Embodiment 14] The measurement apparatus according to Embodiment 11 or 12, further comprising three sensor probes simultaneously positioned with respect to the boundary of the target, wherein the electrical signal phases of the three sensor probes are different from each other by 120 degrees. , Measuring device.
[0055]
[Embodiment 15] A semiconductor manufacturing apparatus equipped with the measurement apparatus according to any one of Embodiments 1 to 14, wherein the target is a semiconductor wafer or / and a transfer master.
[Embodiment 16] The semiconductor manufacturing apparatus according to Embodiment 15, wherein the transfer is performed with the distance between the semiconductor wafer and the transfer original plate being close to 300 μm or less.
[0056]
[Embodiment 17] In an exposure apparatus for exposing a pattern of an original to a substrate,
An exposure apparatus comprising the measurement apparatus according to any one of Embodiments 1 to 14.
[0057]
【The invention's effect】
As described above, according to the present invention, it is possible to prevent a measurement error caused by common impedance or caused by interference between sensors due to an electrostatic field in a measurement apparatus including a plurality of capacitance sensors. For example, in semiconductor exposure transfer, it is possible to reduce the line width, increase the accuracy of line width control, increase the throughput, reduce the cost of the exposure apparatus, and reduce the size. Furthermore, by using a plurality of measurement sensors, it is possible to improve throughput and provide an apparatus with higher productivity.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a measuring apparatus according to a first embodiment of the present invention.
FIG. 2 is an equivalent circuit diagram of the electrostatic sensor of the measuring apparatus according to the first embodiment of the present invention.
FIG. 3 is a relationship diagram between a sensor drive current phase and measurement accuracy of the measurement apparatus according to the first embodiment of the present invention.
FIG. 4 is a block diagram of an X-ray exposure apparatus according to a second embodiment of the present invention.
FIG. 5 is a block diagram of an X-ray exposure apparatus according to a second embodiment of the present invention.
FIG. 6 is an equivalent circuit diagram of an electrostatic sensor of an X-ray exposure apparatus according to a second embodiment of the present invention.
FIG. 7 is a diagram showing the relationship between the operation of the X-ray exposure apparatus according to the second embodiment of the present invention and the stage position.
FIG. 8 is a diagram showing the relationship between the operation of the X-ray exposure apparatus according to the second embodiment of the present invention and the stage position.
FIG. 9 is a phase waveform diagram (part 1) of drive current of each sensor probe of the X-ray exposure apparatus according to the second embodiment of the present invention.
FIG. 10 is a diagram (part 1) showing a ground current and a measurement error of the X-ray exposure apparatus according to the second embodiment of the present invention.
FIG. 11 is a diagram (part 1) showing the ground current and measurement error of the X-ray exposure apparatus according to the second embodiment of the present invention.
FIG. 12 is a phase waveform diagram (part 2) of drive current of each sensor probe of the X-ray exposure apparatus according to the second embodiment of the present invention.
FIG. 13 is a diagram (part 2) illustrating the ground current and measurement error of the X-ray exposure apparatus according to the second embodiment of the present invention.
FIG. 14 is a diagram showing the earth current and measurement error of the X-ray exposure apparatus according to the second embodiment of the present invention (part 2);
FIG. 15 is a configuration diagram of a measuring apparatus according to a conventional example.
FIG. 16 is an equivalent circuit diagram of an electrostatic sensor of a measuring apparatus according to a conventional example.
FIG. 17 is a relationship diagram between a sensor drive current phase and measurement accuracy of a measurement apparatus according to a conventional example.
[Explanation of symbols]
10a, 120a: first sensor probe, 10b, 120b: second sensor probe, 11a, 121a: second sensor amplifier, 11b, 121b: second sensor amplifier, 12, 122: target, 13, 123: sensor cable, 14 , 124: controller, 15: SiC chuck, 16: sensor holding frame, 17: metal surface plate, 18: phase controller, 31: mask, 32: wafer, 33: frame for mask, 34: mask chuck, 35: Mask stage, 36: wafer chuck, 37: wafer stage, 38: X stage, 39: Y stage, 40: surface plate, 41: damper, 42: floor, 43: capacitance sensor probe for wafer measurement, 44: mask Capacitance sensor probe for measurement, 45, 46: sensor probe mounting part, 50: control 51: Stage CPU, 52: Stage DSP, 53: Stage driver, 54: Stage interferometer I / F, 55: Stage interferometer, 56: Sensor I / F, 57a to 57j: First to tenth wafers Electrostatic sensor amplifier, 58: electrostatic sensor amplifier for mask, 59a to 59j: sensor probe for first to tenth wafers, 60: sensor probe for mask, 601 to 610: sensor amplifier for wafer measurement sensor, 611: Sensor amplifier for mask measurement sensor, 125: metal chuck, 127: surface plate, 128: oscillator.

Claims (11)

An apparatus for measuring a distance between a sensor probe and a target to be measured using a capacitance sensor,
A mounting base for mounting the target; and a probe holding member for holding the sensor probe ;
A plurality of sensor probes; a sensor amplifier connected to the sensor probes and outputting a measurement result thereof; and the measurement target including the sensor probes between a first terminal and a second terminal provided in the sensor amplifier. When measuring the distance between the sensor probe and the target to be measured by connecting a system circuit, the phase of the AC electric signal supplied from the sensor amplifier to the sensor probe is set to at least two of the plurality of sensor probes. The measuring device is characterized in that it is different by 180 degrees between the sensor probes . An apparatus for measuring a distance between a sensor probe and a target to be measured using a capacitance sensor,
A mounting base for mounting the target; and a probe holding member for holding the sensor probe;
A plurality of sensor probes; a sensor amplifier connected to the sensor probes and outputting a measurement result thereof; and the measurement target including the sensor probes between a first terminal and a second terminal provided in the sensor amplifier. When measuring the distance between the sensor probe and the target to be measured by connecting a system circuit, the phase of the AC electrical signal supplied from the sensor amplifier to the sensor probe is set to at least three of the plurality of sensor probes. The measuring device is characterized in that it is different by 120 degrees between the sensor probes . The object to be measured target is mounted on a movable target stage, measuring device according to any one of claims 1-2 comprising a target stage control unit for driving and controlling the target stage. Wherein the plurality of sensor probe is mounted on a movable probe stage, measuring device according to any one of claims 1 to 3 comprising a probe stage control unit for driving and controlling the probe stage. Measurement apparatus according to any one of claims 1-4, wherein performing the measurement while changing the relative position of the sensor probe and target. The arrangement of the sensor probe, the target shape, and in accordance with the position coordinates of the target stage or / and the probe stage, according to claim 1 to 5, further comprising a measurement controller for determining the phase of the AC electrical signal to be supplied to each probe The measuring apparatus as described in any one. To the relative position change between the sensor probe to the target, according to the center of the plurality of sensors probes, any one of claims 1 to 6 to arrange the sensor probe to be positioned at the same time with respect to the boundary of the target Measuring device. The phase of the AC electrical signals of the plurality of sensor probes that are simultaneously positioned with respect to the target boundary is such that the measurement value change that occurs in the other sensors is minimized when the plurality of sensor probes pass through the target boundary. The measuring device according to claim 7 , which is determined as follows. The semiconductor manufacturing apparatus which mounts the measuring device as described in any one of Claims 1-8 , and the said target is a semiconductor wafer or / and a transcription | transfer original plate. The semiconductor manufacturing apparatus according to claim 9 , wherein the transfer is performed with a distance between the semiconductor wafer and the transfer master being close to 300 μm or less. The exposure apparatus which exposes the pattern of an original on a board | substrate, The exposure apparatus provided with the measuring device as described in any one of Claims 1-8 .

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