JP3197001B2 - Wafer test and automatic calibration system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a wafer handling / measuring apparatus, and more particularly, to an improved system for handling, processing, and measuring a wafer.

[0002]

Processing machines for handling and measuring semiconductor wafers are well known. Such machines typically have at least one metrology station where they receive wafers and measure various wafer parameters for quality control. A transfer container is used for storing a wafer or transferring a wafer between a measurement station and another station. It is generally desired to provide a measurement station with high throughput, high accuracy and low cost.

[0003]

In accordance with the present invention, a metrology station includes a rotor that rotates while holding a wafer in a plane, and an arm that can move linearly along an axis parallel to the plane of rotation of the wafer. And a scanning sensor attached to the camera. Thereby, a spiral or other scanning path can be realized. The rotor has a plurality of grippers for gripping the wafer. The grippers are attached to the rotor via flexures, which retain the grippers in the plane of the wafer over the entire range of gripper travel. At least some of the grippers have a spring suspension so that the wafer is spring-loaded toward at least two grippers. The at least two grippers are fixed with respect to the rotor while the wafer is supported in the grippers. The metrology station may also include a plurality of calibration gauges supported on the rotor in the plane of the wafer. These calibration gauges have different thicknesses and locations, are grouped into segments that can be removed from the rotor, and include gauges that can be removed from each segment.

According to the measuring station of the present invention, accuracy and throughput speed are improved. The gripper improves measurement point calculation. By using two stationary grippers with known positions, the present invention improves the likelihood of the measurement position for the probe calculation compared to a measurement station where all the grippers are movable. . Furthermore, the movement of the movable gripper of the present invention is restricted to a predetermined axis, so that the calculation of the measurement points is simplified as compared with the measurement station in which the gripper moves on an arc. This improvement in speed and accuracy is most advantageous for large diameter wafers (eg, 300 mm diameter wafers).

According to the master calibration gauge of the present invention, there is no need to handle and replace the calibration wafer, and the calibration can be performed while the wafer to be measured is at the measurement position, thereby improving the accuracy and throughput. Is done. To perform the calibration, the rotor and the plurality of masters are rotated, and the sensors are operated to detect the master mounted on the ring, providing a plurality of comparison points of the capacitance change. This calculates the calibration constant by statistical fitting of the probe transfer function parameters to the data from the master. This allows the simultaneous determination of six coefficients, including linearity, scale factor and offset, for both probes without having to move the wafer into and out of the metrology station.

The rotor is a toroidal (curved body) air bearing structure, which is accelerated to a measured speed and then rotates by inertia during probe data acquisition. The probe arm is a structure supported by an air bearing, and holds the probe at a position where it scans both surfaces of the wafer while the wafer is rotating. With a rotary and linear encoder on the rotor and probe arm, the probe arm is adjusted to draw a spiral or other shaped scan line. The probe arm is dynamically supported on an air bearing.

The raw probe data is digitized and then digitally calibrated, demodulated, and filtered. Thereafter, other signal processing can be performed for display or other purposes.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a wafer handling / processing system has a support frame 110.
Of the wafer 1 in the wafer holder 112 at a predetermined position 114 of FIG.
08 is supplied. The robot 116 moves to the position 11
The wafers 4 can be taken out one by one and placed in a gripper of a measuring station 118 described later. When a series of measurements (typically, flatness, thickness, and shape measurements) on the wafer are completed at the measurement station, the robot 116 places the wafer in the same or a different holder 1.
Return to 12.

The robot 116 is mounted on a slide track assembly on the support frame 110 so that the robot 116 can move on the support frame 110 in the X and Y directions under computer control. The robot has an axis 122 that can move in a vertical direction (z), a tilt direction (φ), and a rotation direction (θ), and the axis supports an arm 126 that holds a vertical paddle 128. The paddle 128 is lowered behind the desired wafer under computer control and the fingers 130 on the paddle 128
The wafer is lifted by the above operation. The robot is in the X direction,
While positioned in the Y and tilt directions, arm 126 is raised and rotated through position 132 to the opposite position to accurately place the wafer in the wafer rotation plane in metrology station 118. . In the measuring station 118, while the gripper releases the wafer, a gripper (to be described later) that has been opened so that the wafer can be inserted closes and picks up the wafer. Next, the robot arm 126
Is returned to an out-of-the-box position before wafer measurement begins. The vertical paddle 128 is sufficiently flexible to allow slight misalignment with respect to the wafer rotation surface in the metrology station 118 to ensure that the wafer is properly positioned within the V-groove of the gripper of the metrology station 118. It has sex.

Referring to FIGS. 2-7, the measuring station includes a base 200, a linear air bearing 202, a guide rail 204, an optical edge sensor 206, a probe arm 208, two sensors 210, and three sets of master calibration gauges 212. , Three grippers 214a, 214b, 214
c, a support plate 216, an air bearing rotor 218, an air bearing stator 220 for the rotor 218, a rotor drive mechanism 222, and a probe arm drive mechanism 224. The air bearing 226 typically has two radial support bearings and two thrust bearings to hold the rotor 218 in a fixed and stable plane of rotation. Stator 220
Is a single 180-degree section, as shown in FIG.
20a. An optical edge sensor 206 is employed to detect the reference position and the edge position. The probe arm 208 is connected to the probe arm carriage 202
It is arranged above. Probe arm carriage 20
2, the guide rail 204, and the base 200 form an air bearing that supports the probe arm in the Y and Z directions.

The gripper 214 and master calibration gauge are located on the rotor. The rotary encoder 219 having the scale 219a and the linear encoder 221 measure the positions of the rotor 218 and the arm 208. In order for the robot 116 to insert and remove the wafer 124, the gripper is arranged at a position that does not interfere with the robot arm 126. The gripper grips the wafer in a surface 231 approximately 1/4 inch outside the surface of the rotor 218.

Before being measured, a wafer is loaded into a measurement station. The wafers are grippers 214a to 214
c is held in the vertical position. Next, the wafer is rotated at a predetermined speed by the drive mechanism 222 of the rotor 218. When the wafer reaches a predetermined rotation speed, the drive mechanism is disconnected by releasing the clutch, and the sensor 21 is turned off.
0 is driven linearly from the center 229 of the wafer to the edge 228 or from the edge to the center. This drive uses a control loop that detects the rotor position while measuring the characteristics of the wafer 124 and moves the arms in coordination to define a spiral or other pattern on the wafer. When the measurement of the surface of the wafer 124 is completed, the rotation of the rotor is stopped, and the wafer is taken out of the measurement station.

The grippers 214a to 214c have a function of holding the wafer at a repeatable measurement position. During the measurement, two grippers, for example 214a and 214b, are stationary with respect to the rotor, and the other gripper 214c is movable, whereby the wafer is pressed and held against the stationary gripper. Stator 220 aligned with gripper to position wafer at measurement position
The gripper is opened by the upper actuator 215. The wafer is moved to a predetermined position where the wafer surface is aligned with the gripper surface. The wafer is inserted between the grippers released from the actuator 215 and in contact with the wafer edge. The grippers exert an inward force on the wafer to ensure that all three grippers secure the wafer to the rotor. As shown in FIG. 8, the gripper has a V-shaped groove 900, which guides the wafer edge to a predetermined position. The V-shaped groove has a V-shaped angle of about 90 degrees 9
02 and the block depth 904 is thin enough to allow the probe to pass through. The center position of the wafer is repeatable because the two grippers do not move during measurement and are at precisely known positions relative to the sensor and the wafer. Optical sensor 206
Provides data at the edge position, reference position, and center position to correlate wafer metrology data with accurate wafer position in computer 2001, as is known in the art.

The gripper 214 is attached to the rotor by a flexible body 1000 shown in FIGS. 9 and 10A. Each flexible body can hold the movement of the gripper in one shaft 1002. The flexure includes a base plate 1004, which is directly connected to the rotor and also at a first end to two parallel arms 1006. A central arm 1008 is connected at a second end to the parallel arm, and the opposite end of the central arm is connected to a gripper finger V-groove block 1010,
Thus, a W-shaped flexible body support 1012 is formed. With this configuration, two counteracting
Hinge shafts 1014a, 1014b are formed which maintain the movement of the gripper fingers within a predetermined axis when pressure is applied to the central arm to hold the wafer. The opposite direction of the hinge axis (counteractin
g) is assisted by an in-arm split 1016 having openings 1020 at both ends. With the split and the aperture, the arm functions as a parallelogram. That is, the upper 1022 and lower 10
24 bends. This design simplifies the positioning of the wafer as compared to one in which the gripper moves in an arc. For two of the flexures 1000, their inward motion is limited by a hard stop formed by the pin 1005 and the edge 1007. Other flexures have a larger operating range, only the position of which depends on the wafer dimensions. A spring 1003 is disposed through a hole 1001 in the plate 1004 and presses against an arm 1008 adjacent to each flexible block 1010. Thereby, the rigid stopper mechanism is engaged so that the more movable block 1010 is appropriately biased by the spring. To maintain the engagement of the rigid stopper mechanism, the two flexible springs 1003 whose movement is restricted by the rigid stopper mechanism are stronger than the others.

The actuator 1028 is connected to the stator 22
0 are arranged at equal intervals. As described above, the stator does not rotate during measurement. Thus, the gripper can only operate when aligned with the actuator. The gripper is
It is important that the reference point can only contact and fix the wafer, and that this reference point is only one notch.
If a reference point with a flat part is used, the flat part must be avoided, for example by alignment before loading.

The actuator 1028 shown in FIG. 10B
By (215), a force is applied to each flexible body 1000. The actuator is lever 1030 and bellows 103
2 and the bellows are disposed in the frame 1034. The bellows is substantially hollow and has an air inlet 10.
36. This allows the bellows to expand and contract according to the air pressure at the air inlet. When the bellows expands, it applies force to the lever,
As a result, a force is applied to the central bar of the flexible member on which the V-shaped groove block is placed. Thus, when the actuator 1028 and the gripper are aligned for expanding the gripper by rotation of the rotor by the drive mechanism 222, the gripper can be opened for wafer insertion.

In FIG. 1 to FIG. 4, when the wafer is fixed at a predetermined position, the rotor is rotationally accelerated by a driving mechanism 222 with a clutch, and the wafer is similarly rotated. After the clutch of the drive mechanism is disengaged, the rotor rotates by inertia, at which time the sensor 210 moves linearly, for example, in an axis 232 substantially parallel to the wafer rotation plane, between the edge of the rotating wafer and the center of the wafer. Is moved, thereby scanning the surface of the wafer. By moving the sensor linearly with respect to the rotating wafer, a spiral scanning pattern as shown in FIG. 11 is obtained. It will be appreciated that by placing respective scanning arms and sensors on both sides of the rotating wafer, it is possible to measure both surfaces of the wafer simultaneously.

The operation of the probe is performed by a servo loop shown in FIG. The computer 2001 controls the head 219 and the scale 2 when the rotor is moving by inertia.
19a. The rotor angle is received from the angle encoder 2005 having The linear drive mechanism 224 drives the arm support 202 so that the output of the linear encoder 2003 indicating the linear position of the probe becomes an appropriate value for obtaining a predetermined spiral or other trajectory pattern. The spiral trajectory is controlled by the computer 2001 so as to start from the same predetermined position with respect to the reference.

As shown in FIGS. 6A and 6B, the linear air bearing includes a vacuum duct 600 and a pressure duct 602, which allow the sensor arm 208 to
4 along the air cushion. The pressure duct provides air pressure to lift the sensor arm, and the vacuum duct scavenges air exhausted by pressure from the pressure duct, eliminating the possibility of introducing contaminants into the wafer and providing a bearing Apply preload.

Referring to FIGS. 3, 4, 12 and 13,
The sensor is a capacitive displacement sensor having an inner capacitive plate 1200 and an outer capacitive plate 1202, respectively. The sensor corresponds to that disclosed in U.S. Pat. No. 4,918,376, which is incorporated herein by reference. The capacitance of the sensor varies inversely with the distance 1204 between the sensor and the surface to be measured. Together with the wafer surface area being measured, the sensor forms a three-sided capacitor from which measurements can be made. More specifically, the output of the sensor is an AC signal Vo with a known period, representing the distance between the sensor and the surface to be measured of wafer 124. The thickness and flatness as the characteristics of the wafer, and the shape including bending and warping are obtained from the sensor output using a known technique. Such techniques are described, for example, in U.S. Pat. Nos. 3,990,005, 4,860,229, 4,7
No. 50,141, which are incorporated herein by reference.

2 to 6, the measuring station is also devised to improve the measuring accuracy by reducing the vibration of the operating measuring station.
For example, the probe arm 208 of FIG. 2 is kinematically mounted to the air bearing 202 through a journal and pin connection 230 to minimize distortion due to manufacturing and assembly accuracy. Dynamic mounting can minimize measurement errors caused by non-ideal behavior of the air bearing during linear operation of the probe arm.

As shown in FIGS. 14, 15A, 15B, 15C and 16, the rotor 218 is supported by an air bearing system consisting of the rotor itself and the four surfaces of the stator assembly. There are two thrust bearing surfaces 3004 and two radial bearing surfaces 3000. These surfaces are in communication with a vacuum source 1604 and a pressure source 1606. The channels of the thrust bearing 3004 and the radial bearing 3000 connect the boundary between the rotor and the bearing of the stator to a vacuum source and a pressure source. Positive pressure applied to the thrust and radial bearings pushes the rotor away from the bearing, thereby creating a gap between the rotor and the bearing. In this way, the rotor rides on a cushion of air. A vacuum source is provided at the scavenging section 30 at the edge of the boundary.
08 and pockets in the stator. In order to recover the air flowing out of the pressure source channel and preload the rotor against the radial bearing,
The vacuum is balanced with the pressure source. The scavenging unit 3008
This reduces the possibility of pressurized air or environmental impurities accumulating on the wafer.

Referring to FIGS. 7 and 17, the measuring station includes a plurality of master calibration gauges (also referred to as "masters").
212, which are used to improve accuracy and throughput. In the preferred embodiment, rotor 218
Has 30 removable carbide steel masters 212
Which can have five different thicknesses and include 19 different spacers to provide different axial positions. The 30 masters are divided into three sets,
It is located in the same plane as the vertical wafer and is slightly offset for calibration. Each set includes one removable master arc 700 and each master 212
02 is connected to the master arc. Since there are 6 calibration parameters and 30 data points are obtained from the master, the 30 data points provide redundant data. Therefore, statistical approximation and operation with less data than all 30 masters can be performed. The calibration by the master can be performed before or after wafer measurement, and can be completed in a relatively short time because insertion and removal of a standard wafer is not required. Therefore, it would be desirable to calculate calibration values both before and after wafer metrology to compensate for thermal drift errors.

To calibrate with master 212,
First, the rotor is accelerated to a certain rotational speed, and the master is measured by a capacitance sensor. The output of the capacitance sensor is converted to a digital value representing the detected capacitance. In this way, linearity, scale factor and offset are determined simultaneously without having to move a standard (comparative) wafer into and out of the metrology station.

The master provides comparison points for thickness / volume variations from which statistical transfer of the parameters of the probe transfer function to data taken from the master in computer 2001 by a statistical fit. A calibration constant is calculated. After the calibration data is collected, the linearity, scale factor, and offset parameters are adjusted for each capacitive transducer channel according to the modeled transducer characteristics. For optimal results, a least squares fit is used. The output model of each capacitance converter is represented by the following equation.

(Equation 1) Where Vo = output voltage K = converter scale factor Cp = probe capacity Vofs = offset voltage The probe capacity is expressed by the following equation.

(Equation 2) Here, εo = dielectric constant of free space A = area of capacitance sensor d = distance between sensor and target Co = offset capacitance Substituting Equation 2 into Equation 1 gives the following results.

(Equation 3) When the Co term is zero, Equation 4 is linear with d, which is the optimal case. To measure the difference in thickness using two capacitive probes, the analysis software
Subtract the distance of each transducer channel from the distance between the probes.
For that purpose, equation 3 is solved for d and substituted into equation 5 below.

(Equation 4) Where thkg = thickness measured by gauge D = distance between probes da = distance measured by transducer a db = distance measured by transducer b Thickness error for measurement in the middle of the calibration procedure Is the square of the difference between the master thickness and the measured thickness. Thus, the sum of the squares defines one function:

(Equation 5) Where thkmn = thickness of the nth master thkgn = thickness of the nth master In this function, the output of each transducer is described as a function of three variables, and the probe area is assumed to be constant. Have been. Therefore, a seven-dimensional surface is described. To find the minimum error, calculate the lowest point on the surface.

In FIGS. 14, 19 and 20, data processing during the measurement and calibration cycle is improved by direct digitization of the sensor output. As described above, the sensor front ends 1400a and 1400b output the sine waveform output signal Vo whose amplitude changes according to the change in distance.
(A) and Vo (b) are provided. The sine waveform output signals of the sensor front ends A and B are converted to digital values in the dual AD converter 1906. The multiplexer 1901 replaces the probe signal with the reference signal whenever necessary to take on the characteristics of the AD converter. The AD converter outputs the digital data output stream 1
To provide 910, the analog signals 1908a and 1908b are sampled three times per cycle, and this data output stream is provided to the computer 2000 for processing. The sampling points are periodic and equally spaced.

As the AD converter, typically, a high-resolution, 20-bit resolution, low noise, very good differential nonlinearity, and a conversion rate of up to about 50 KHz,
AC accurate sigma-delta analog-to-digital converters are available. AD converter 1
906 is used to directly digitize the output of the probe front end. The AD converter is clocked to synchronize at three times the probe excitation frequency. Demodulation, calibration, scaling and other desired arithmetic operations are performed in the digital domain. Direct digitization can eliminate a significant portion of the analog circuitry previously required.

Computer interface 2000 and computer 2001 execute software operable to provide wafer metrology data from digital data stream 1910. First step 2
At 002, the digital data is linearized and the scale factor settings are applied. In other words, the calibration data is applied to the digital data. In a second step 2004, the data output of the first step is synchronously demodulated. After demodulation of the data, the data output is multiplied by a reference sine wave of the same phase and frequency as the excitation signal. Typically, demodulation is performed digitally. Demodulation step 2004 provides a baseband signal, which is
In order to remove sidebands and reduce noise, a filtering step 2006 digitally filters. In order to select the positions of points to be measured on the wafer, the output of the dual A / D converter is electrically tagged at the position where the probe is detecting these points on the wafer.
Is attached. Electrical indicators are used in the signal processing circuitry to determine which readings to take as a record for subsequent processing and which readings to discard.

While the preferred embodiment of the present invention has been described, it will be apparent to those skilled in the art that other embodiments incorporating that concept may be used. Therefore, the present invention should be limited only by the spirit and scope of the appended claims.

[Brief description of the drawings]

FIG. 1 is an isometric view of a wafer handling and measuring apparatus according to the present invention.

FIG. 2 is a front view of the measuring station in FIG. 1;

FIG. 3 is a rear view of the measuring station.

FIG. 4 is a side view of the measuring station.

FIG. 5 is a top view of the measuring station.

FIG. 6 is a perspective view of a measuring station.

FIG. 6A is a bottom view of a linear air bearing.

FIG. 6B is a cross-sectional view of the bearing of FIG. 6A taken along line BB.

FIG. 7 shows a rotor.

FIG. 8 is a view showing a gripper.

FIG. 9 is a perspective view of a gripper assembly.

FIG. 10A is a top view of the gripper assembly.

FIG. 10B is a diagram showing a gripper actuator.

FIG. 11 is a diagram showing a wafer scanning pattern obtained by a measurement station.

FIG. 12 shows a sensor probe.

FIG. 13 shows a sensor probe.

FIG. 14 is a sectional view of the stator and the rotor taken along line BB of FIG. 15A.

FIG. 15A is a side view of a stator and a rotor.

FIG. 15B is a front view of the stator and the rotor.

15C is a sectional view taken along line CC of FIG. 15B.

FIG. 16 is an enlarged sectional view of the arcuate air bearing of FIG. 15;

FIG. 17 shows a master calibration gauge.

FIG. 18 is a flowchart showing processing of measurement data according to the present invention.

FIG. 19 is a flowchart showing processing of measurement data according to the present invention.

[Explanation of symbols]

104 ': wafer, 108: wafer, 110: support frame,
112: holder, 114: predetermined position of support frame 110,
116: robot, 118: measuring station, 12
2: axis, 124: wafer, 126: arm, 128: paddle, 130: finger, 132: position, 200: base, 202: bearing (probe arm carriage), 20
4: guide rail, 206: optical edge sensor, 20
8: probe arm, 208a: arm, 208b: arm, 210: sensor, 210a: sensor, 210b:
Sensor, 212: master calibration gauge, 214a: gripper, 214b: gripper, 214c: gripper, 215
a: Actuator, 215b: Actuator, 21
5c: actuator, 216: support plate, 218: rotor, 219: rotary encoder (head), 219
a: scale, 220: stator, 220a: cover,
221: Encoder, 222: Drive mechanism, 224: Drive mechanism, 226: Bearing, 228: Edge of wafer, 22
9: center of wafer, 230: connection of journal and pin,
231, surface, 232: axis, 600: vacuum duct, 60
2: pressure duct, 700: master arc, 702: shim, 900: V-shaped groove, 902: V-shaped angle, 904: block depth, 1000: flexible body, 1001: hole, 1002:
Shaft, 1003: spring, 1004: plate, 1005: pin,
1006: parallel arm, 1007: edge, 1008:
Arm, 1010: block, 1012: support, 10
14a: hinge axis, 1014b: hinge axis, 1016:
Split (split) in arm, 1020: opening, 10
22: Upper arm, 1024: Lower arm, 102
8: Actuator, 1030: Lever, 1032: Bellows, 1034: Frame, 1036: Air intake,
1200: inside capacity plate, 1202: outside capacity plate, 120
4: Distance between sensor and surface to be measured 1400a: Front end A, 1400b: Front end B, 14
02: programmable excitation source, 1604: vacuum source, 16
06: pressure source, 1901: computer controlled multiplexer, 1906: dual A / D converter, 1908a:
Analog signal, 1908b: Analog signal, 1910:
Digital data stream, 2000: computer interface circuit, 2001: computer, 200
2: Data calibration, 2003: Linear encoder, 200
4: data demodulation, 2005: rotary encoder, 20
06: Filtering and request data point selection, 200
8: selection data addition processing, 2010: selection data storage, 3000: radial bearing, 3004: thrust bearing, 3008: scavenging section.

Continuation of front page (72) Inventor Noel S. Podzije, United States, 02194 Massachusetts, Needham Heights, Nevada Road 47 (72) Inventor Alexander Belyaev United States, 01778 Massachusetts, Wayland, Rice Road 52 (72) Inventor Pitter A. Harvey United States, 01887 Church Street, Wilmington, MA 01887 (72) Richard S. Inventor. Smith United States, 01451 Littleton Road, Harvard, Mass. 331 (56) References JP-A-7-280741 (JP, A) JP-A-62-284248 (JP, A) JP 5-24005 (JP) , Y2) (58) Field surveyed (Int. Cl. ⁷ , DB name) H01L 21/66

Claims (11)

(57) [Claims] An apparatus for rotatably supporting a semiconductor wafer for testing at least one of flatness, thickness, and shape of the semiconductor wafer, comprising: a plurality of grippers for holding the wafer for rotation; And an encoder that electronically indicates the rotational position of the rotor; and a rotor that is disposed around the rotor and holds the wafer vertically inside the rotor in a V-shaped groove block. The gripper has a W-shaped support having a plurality of slit arms, and a V-shaped groove block attached to one inner W arm is connected to a rotor of the two outer W arms. Move relative to the mounting attachment, the movement being linear due to the parallelogram structure of the W-arm. A resilient suspension for the gripper for applying a load, the at least two grippers resisting movement toward a wafer beyond a predetermined position relative to a rotor while the wafer is supported in the gripper; A plurality of calibration gauges supported on the rotor in the plane of the wafer, the calibration gauges having different thicknesses and locations, and grouped into a plurality of segments that can be removed from the rotor. A calibration gauge that can be removed from each segment and a wafer test probe that provides an output signal indicative of the distance, the distance between the wafer and the wafer when the wafer is supported in the rotor. Supported in a probe arm movable in a plane substantially parallel to the plane of the wafer supported above one surface in the apparatus for measurement And a central elongated ridge on the surface that mates with an air-supported probe arm support that dynamically supports the probe arm thereon; and a linear projection of the probe arm above the surface. A linear encoder that electronically defines the position; a rotor drive mechanism that provides rotation to the rotor and disconnects the rotor to cause rotation by inertia; and provides a linear motion to the probe arm, wherein the probe passes through the encoder. Moving across the two sides of the wafer in response to the inertial rotation of the rotor, moving the probe in a predetermined pattern across the surface of the wafer, and providing a scan with the probe of the calibration gauge. A probe arm driving mechanism, connected to the rotor driving mechanism and a probe, and an inertia of the rotor. In the course of rolling, the pattern and the at the selected point in the calibration trace, anda measurement controller taking data. 2. The signal processing apparatus for an output signal representing a probe distance according to claim 1, wherein the signal is an AC excitation unit that excites the probe at a certain frequency, and an output signal therefrom is an AC signal of the frequency. AC excitation means, a digital sampler that samples the AC output signal as a digital value at least twice in each cycle at the frequency to form a sample stream of the digital output signal of each probe, and a digital sampler of the digital output signal. A marker for marking a selected signal periodically generated from a; a synchronous demodulator, a baseband and noise filter for creating a stream of signals represented by DC from each sample stream; and a stream of signals represented by DC. A remover for removing the unmarked signal of No. processing unit. 3. A wafer measuring station capable of measuring at least one physical property of a wafer, wherein the fixed station is disposed inside the stator and disposed between the stator and the rotor. A rotor that rotates in the same plane as the stator by an air bearing; a plurality of grippers disposed on the rotor and vertically gripping the wafer during measurement; and disposed on a linear air bearing. A sensor movable along an axis substantially parallel to the plane of rotation of the rotor, whereby the wafer is held in the measurement station by a gripper, rotated in a plane, and A metrology station that is configured to be scanned by a sensor that moves linearly in a scan axis, thereby providing a helical scan path. 4. The measuring station according to claim 3, wherein
A measuring station, wherein at least two of said grippers are stationary and at least one is movable during measurement. 5. The measuring station according to claim 4, wherein
A measuring station, wherein the gripper is connected to the rotor by a W-shaped support flexure having opposing hinges. 6. The measuring station according to claim 5, wherein
The flexible body has a base plate directly connected to the rotor, the base plate being connected at a first end to two parallel arms, the two parallel arms being at a second end. A central arm connected to the gripper finger V-groove block to effect opposite movement at the opposite end, the opposite movement being assisted by a split formed in said arm, and Is
Openings at both ends to allow the arms to operate as parallelogram links, so that the upper and lower portions of each arm can bend at different rates when the arms bend The measuring station characterized by being constituted as follows. 7. The measuring station according to claim 3, wherein
A metrology station comprising: a plurality of calibration gauges disposed on the rotor such that the wafer is substantially in the plane of the wafer when held by the gripper. 8. The measuring station according to claim 7, wherein
At least thirty master calibration gauges disposed on three master arcs equally spaced on the rotor, each of the master calibration gauges having a total of at least five different thicknesses. A measuring station, characterized in that the value has a thickness represented by the master calibration gauge. 9. The measuring station according to claim 3, wherein
A measuring station, wherein the sensor is disposed on a dynamic mounting. 10. An apparatus for rotatably supporting a semiconductor wafer for testing at least one of the flatness, thickness and shape of the semiconductor wafer, wherein a plurality of grippers are spaced apart for holding the wafer for rotation. And an encoder that electronically indicates the rotational position of the rotor; and a rotor that is disposed around the rotor and holds the wafer vertically inside the rotor in a V-shaped groove block. The gripper has a W-shaped support having a plurality of slit arms, and a V-shaped groove block attached to one inner W arm is provided on the two outer W arms. Move relative to the attachment to the rotor,
Linear with the parallelogram structure of the arm, further comprising an elastic suspension for the gripper for applying an elastic spring load towards at least two of the grippers, wherein the at least two grippers have a wafer While being supported in the gripper, the rotor is held so as to resist operation toward a wafer beyond a predetermined position with respect to the rotor, and is supported in the plane of the wafer on the rotor. A plurality of calibration gauges having different thicknesses and locations, grouped into a plurality of segments removable from the rotor, the calibration gauges providing a calibration gauge removable from each segment and an output signal indicative of the distance. A wafer test probe for measuring a distance to a wafer between the wafers when the wafer is supported in the rotor. A probe supported in a probe arm movable in a plane substantially parallel to a surface of a wafer supported above one surface in the apparatus; and air dynamically supporting the probe arm thereon. A central elongated ridge on the surface that mates with a probe arm support supported by the probe arm; a linear encoder that electronically defines a linear position of the probe arm above the surface; and A rotor drive mechanism that separates the rotor so as to rotate according to the above, a linear motion is applied to the probe arm, and the probe moves across the both surfaces of the wafer through the encoder in accordance with the rotation due to the inertia of the rotor. The probe moves in a predetermined pattern across the surface of the wafer, and is moved by the probe of the calibration gauge. A probe arm drive mechanism, and a measurement control device connected to the rotor drive mechanism and the probe, and taking data at selected points in the pattern and the calibration trace during the inertial rotation of the rotor, An apparatus comprising: 11. A signal processing apparatus for an output signal representing a probe distance according to claim 10, wherein the signal is an AC excitation means for exciting the probe at a certain frequency, and an output signal therefrom is an AC signal of the frequency. AC excitation means, a digital sampler that samples the AC output signal as a digital value at least twice in each cycle at the frequency to form a sample stream of the digital output signal of each probe, and a digital sampler of the digital output signal. A marker for marking a selected signal periodically generated from a; a synchronous demodulator, a baseband and noise filter for creating a stream of signals represented by DC from each sample stream; and a stream of signals represented by DC. A remover for removing the unmarked signal of Signal processing device.