JPS6213045A - Foreign material inspecting device for wafer - Google Patents

Abstract

PURPOSE:To plot a foreign material on a wafer profile image of the prescribed direction by correcting the rotating direction position of the material according to the offset angle of the wafer. CONSTITUTION:An electrostatic capacity displacement meter 53 is provided as a sensor for detecting a foreign material of a wafer 30 oppositely to the wafer surface, an output signal is input to a level comparator 103, and compared with the specific threshold value. A foreign material detection signal output from a photomultiplier 90 is amplified by an amplifier 100, and the input to a level comparator 102. An interface circuit 108 inputs signals which indicate rotating direction position theta and X-direction (radial direction) position (x) at each time point from rotary and linear encoders. A microprocessor 120 corrects the rotating direction position of the detected foregin material on the basis of them, and plots the position on a wafer profile image on a CRT128.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wafer foreign matter inspection device that automatically detects foreign matter on the surface of a wafer 1 such as an LSI river.

[Prior Art] There is a wafer foreign matter inspection device that detects foreign matter on the surface of a wafer while spirally scanning the surface of the wafer placed on a rotation stage.

Such conventional wafer foreign object inspection equipment detects foreign objects by moving a rotary stage in a specific direction while rotating, and detecting foreign objects by scanning the wafer on the rotary stage 1 in a spiral manner using a detection system. If so, the rotational direction position 16 and specific direction position of the rotary stage at the time of detection are read as the foreign object position and stored in the memory. In addition, the outline of the wafer is detected in the same way as foreign objects, a wafer outline image is drawn as a series of foreign objects, the detected foreign objects are plotted within the wafer outline image, a foreign object map is created, and the percentage map is Print out using a Y plotter.

[Problems to be solved] As described above, in the conventional wafer foreign matter inspection device 6,
Although the position of the detected foreign object in the rotation direction JJ is the rotational direction position of the rotation stage, the angle at which the wafer is attached to the rotation stage is not constant, and there are variations in the offset angle between the wafer and the rotation stage. In other words, the rotational direction position of a foreign object detected on a certain wafer is
-The actual location of the wafer is 1, not the actual location.
− is meaningful, and therefore the position information of the foreign object cannot be used as is as data for data processing. For example, when controlling the distribution of foreign particles on a large number of wafers,
It is impossible to directly obtain a from the position information of the detected foreign object, and requires operations such as reading the position of the foreign object from the foreign object map via the person P.

In addition, in the case of conventional wafer foreign particle inspection equipment, the orientation of the wafer outline image is determined according to the angle when the wafer is mounted on the rotation stage. to)
The position of the foreign matter map varies, making it difficult to see the foreign matter map, making it inconvenient to compare with a standard foreign matter map or compare foreign matter maps of multiple wafers side by side.

[1st aspect of the invention] This invention was made in view of such problems in the prior art, and the 1st point is that the attachment of the sea urchin/1 to the rotation stage is possible by removing foreign objects that are not affected by angle variations. It is an object of the present invention to provide a wafer foreign particle inspection device that can obtain positional information on a wafer and, furthermore, a foreign particle map with a fixed orientation according to such positional information.

[F Means for Solving the Problems] In order to achieve the first objective, according to the present invention, the surface of the wafer placed on a rotation stage is scanned in a spiral manner. In the wafer foreign object inspection apparatus for detecting the above four objects, an offset angle detection means detects an offset angle of the wafer of the rotating stay sheet with respect to the rotating stage, and according to the offset angle detected by the offset angle detection stage, Detected〃1
11: position correction means for correcting the rotational direction position of the object;
There are provided means for plotting the foreign matter captured by the position correction means on a wafer contour image in a fixed orientation to generate a material map, and means for applying the W material map generated by the means.

[Operation] By correcting the rotational direction position of the foreign object according to the offset angle of the wafer, it is possible to obtain positional information of the I/li object with the influence of angular variations removed when mounting the wafer.

Also, according to the position information of such foreign objects, the foreign objects are plotted on the wafer outline image with a constant -5 = orientation, which is a constant orientation! /l! The object map can be viewed.

[Embodiment Code] An embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram showing a simplified configuration of the optical system portion of the wafer foreign matter inspection apparatus and the apparatus according to the present invention. In this figure, IO is an X stage supported by a base 12 that slides in the X direction.

A screw 16 directly connected to the rotating shaft of a stepping motor 14 is screwed into the X stage 10, and by operating the stepping motor 14, the X stage 10 can be moved forward and backward in the X direction. 18 is a linear encoder that generates a code signal corresponding to the X direction position IHX of the X stage 10.

Two stages 20 are attached to the X stage IO so as to be movable in the Z direction. Its transportation means are omitted in the figure. A rotary stage 22 on which a wafer 30 as an object to be inspected is placed is rotatably supported by the Z stage 20 . Here, as the wafer 30, a wafer with a blank film, a mirror wafer, or a wafer with a pattern can be set and inspected.

This rotary stage 22 is connected to a DC motor 924, thereby being driven to rotate in a specific direction. This single white current motor 24 has a rotary stage 2
A rotary encoder that outputs a code signal corresponding to rotational direction position 0 of No. 2 is built-in.

Note that the wafer 30 is placed on the rotation stage 22 by f11F suction.
It is positioned and fixed by t, but the means for that purpose is omitted in the figure.

This wafer foreign matter inspection device automatically inspects foreign matter on the wafer 301t using polarized laser light, and the S-polarized laser light is irradiated onto l+r+i (blue and white to be inspected) of the wafer 30. For this purpose, the S-polarized laser oscillator 38
．． 38 are provided. Each S-polarized laser oscillator 38.
38 generates S-polarized laser light of a certain wavelength,
For example, the wavelength is 83.

The S-polarized laser beam is transmitted from the Y direction to the 1-
It6 is irradiated onto the surface at an irradiation angle φ of approximately 2 degrees. Since the irradiation angle is small in this way, when a beam of S-polarized laser light with a circular cross section is irradiated, the spot on the Ueno\ plane becomes long (extended) and sufficient irradiation density cannot be obtained. A cylindrical force lens 44.48 is placed in front of the S-polarized laser oscillator 38.
The S-polarized laser beam with an almost circular cross section emitted from 38 is
The beam is narrowed down to a flat cross-sectional shape that is collapsed in the Z direction, and then irradiated onto the wafer.

Here, in the case of a wafer 1 with a blank film without a pattern (or a mirror wafer), the S polarized laser beam is
If there is no foreign object within the emission spot, the light will be reflected and will not be reflected in two directions; however, if there is a foreign object, it will be diffusely reflected and reflected in two directions.

On the other hand, in the case of a patterned wafer, the reflected laser beam of the S-polarized laser beam irradiated onto the wafer will also be reflected in the Z direction if a pattern exists within the irradiation spot. Microscopically, ~] is smooth, so the reflected laser light is almost only an S-polarized component. On the other hand, since the surface of a foreign object has minute irregularities, if a foreign object exists within the irradiation spot, the irradiated S-polarized laser light will be scattered and the polarization direction will change, and the reflected laser light will be ,
In addition to the S-polarized light component, a considerable amount of the P-polarized light component is included.

#IIL In this wafer foreign matter inspection system, in the case of patterned wafers, the presence or absence of foreign matter can be determined based on the level of the P-polarized light component contained in the laser beam reflected from the wafer in the Z direction. Detect the size of foreign objects.

On the other hand, in the case of wafers with blank films (including mirror-finished wafers), in order to increase detection sensitivity, the presence or absence of foreign particles and their size are determined based on the levels of S-polarized reflected laser light and P-polarized reflected laser light in two directions. Detect.

rsf and see FIG. The reflected laser light from the wafer is incident on a detection system 50 that detects foreign matter according to the principle described above. That is, the reflected laser light reaches the 45-degree prism 60 via the objective lens 54, the half mirror 56, and the prism 58.

Further, a lamp 70 is provided for 1-1 visual observation. Visible light emitted from the lamp 70 illuminates the wafer through the half mirror 56 and the objective lens 54.

The visible reflected light that has entered the microscope 52 side via the prism 60 is transmitted through a 60 degree prism 62, a field lens 64,
The light passes through the relay lens 66 in order and enters the eyepiece lens 68. Therefore, the wafer 30 can be observed with a sufficiently large magnification through the eyepiece 68. In this case, the range of the S-polarized laser beam spot on the wafer 1t is located at the center of the field of view (however, the S-polarized laser beam is not irradiated during visual observation). The wafer 30 can also be observed at low magnification through the prism 58.

The reflected laser light that has entered the detection system side via the prism 60 passes through the aperture 4 provided in the slit 72 and is sent to the photomultiplier 90.

Here, if the wafer 30 is a patterned wafer,
Since the S polarization cut filter 86 (polarizing plate) is moved to the position indicated by the symbol 86°, the P polarization of the reflected laser beam is
Only the polarized light component is extracted and enters the photomultiplier 90. When the wafer 30 is a wafer with a blank film (or a mirror wafer), the S polarization cut filter 86 is moved to the position shown by the solid line, so that both the S polarization component and the P polarization component of the reflected laser light enter the photomultiplier 90. . As will be described later, based on the level of the detection signal of the output signal (detection signal 1) of the photomultiplier 90, the presence or absence of a foreign object within the field of view of the aperture 4 of the wafer 1- and the particle size of the foreign object are determined. It will be judged.

87 is a solenoid for moving the S polarization cut filter 86.

Here, the foreign matter inspection is performed while rotating the wafer and feeding it in the X direction (radial direction) as described above. According to such movement of the wafer 30, the spot 30A of the S-polarized laser beam moves spirally from the outside toward the center of the wafer 30, as shown in FIG. The detection system 50 and the microscope 52 are stationary, and the field of view of the aperture 4 is always included within the spot 30A and moves to follow the spot 30A. That is, the wafer is inspected while being spirally scanned.

Here, the irradiation angle φ will be explained. In conventional wafer foreign matter inspection equipment, when inspecting foreign matter on a wafer whose surface is coated with a blank film without a pattern, such as a photoresist film or aluminum vapor deposition film, the light beam is emitted at a fairly large irradiation angle, for example, 30 degrees. The wafer itself is irradiated.

According to the inventor's research, the background noise of the detection signal in such conventional devices includes not only noise components determined by the state of the wafer surface (the surface of the blank film) but also noise related to the state inside the blank film. component and a noise component related to the condition of the wafer substrate under the blank film. Principle of utilizing reflected light from the wafer surface - 1-1 It is impossible to completely remove the first noise component, and its influence is not fatal. However, the latter two noise components are
It is affected by the internal state of the wafer and directly causes false detection, so it should be removed.

According to the inventor's research, in conventional equipment, because the beam irradiation angle is large, a part of the light beam incident on the wafer surface enters the interior of the blank film and is reflected on the wafer base surface, causing ILP and blank film damage. It was found that the above-mentioned undesirable noise component was generated because the light passes through the wafer surface, emerges from the wafer surface, and enters the photoelectric element r.

Therefore, in this embodiment, the irradiation angle of the light beam is selected to be 1.0 min smaller as described above so that the light beam is substantially totally reflected by the wafer, thereby preventing the light beam from penetrating into the wafer. -I'm looking forward to it.

+i1 and FIG. Near the objective lens 54,
A displacement meter 53 is provided in the electrostatic field facing the wafer. This electrostatic container displacement meter 53 is provided as a sensor for detecting the orientation flat portion of the wafer 30, and during wafer rotation for offset angle detection, which will be described later, the capacitive displacement meter 53 is slightly smaller than both ends of the orientation flat 30B of the wafer 3o. The electrostatic capacitance displacement A] 53 is arranged so that the inner part thereof passes directly under the electrostatic field M displacement meter.

Next, the reliability processing and control system of this wafer foreign matter inspection apparatus will be explained with reference to FIG.

The detection signal output from the photomultiplier 90 is input to the level comparison circuit 102 while being amplified by the amplifier 'fA100.

Here, there is a relationship as shown in FIG. 4 between the particle size of the foreign matter on the wafer 1- and the level of the m output signal. In this figure, Ll + L2 + I-J is the threshold of the level comparison circuit 102.

The level comparison circuit 102 compares the level of the detection signal with each threshold value, and outputs a binary code indicating the result of comparison with each threshold value. For example, if the detected signal level is less than the threshold, (
000)2, and the detection signal t) level is equal to or higher than the threshold L2.
-, if it is less than the threshold (lI!IL J), outputs (011)2, and if the detection signal level is 1- than the threshold fg'[L3, then (
111) Output 2.

The output code of each level comparison circuit 102 is input to an interface circuit 108 that interfaces with the data processing system 104.

For the electrostatic field, the output No. 45 of the displacement meter 53 is the level comparison circuit 10.
3 and compared to a specific threshold.

The output signal of this level comparison circuit is input to the interface circuit 108.

Further, the interface circuit 108 receives information from the rotary encoder and the linear encoder to indicate the rotation direction position 0 and the X direction ('l') at each time point.

The code (binary code) indicating the information on position X (radial direction) is
It is manually input via buffer circuits 110 and 112.

Each input code to the interface circuit 108 is
The data is taken into a certain register inside the interface circuit 108 at a constant cycle and temporarily held there.

Further, inside the interface circuit 10B, there is also a register in which control information for the stamping motor 14, DC motor 24, and solenoid 87 is set by the data processing system 104. According to the control information set in this register, the motor controller 11B controls the drive of the motors 14 and 24, and the solenoid driver 117 controls the drive of the solenoid 87.

Data processing system 104 includes microprocessor 12
0, ROM 122, RAM 124, floppy disk device 12B, X-Y plotter 127, CRT display device 12B, keyboard 130, etc. 132
is the system bus, and the microb 0 set + 120-
ROM 122, RAM 124, and the interface circuit 108 are directly connected.

The keyboard 130 is used by an operator to input various commands and data, and is connected to the system bus 132 via an interface circuit 134. The floppy disk device 126 stores an operating system, various processing programs, test result data, etc., and is connected to the system bus 132 via a floppy disk controller 136.

When this wafer foreign matter inspection device is started, the operating system is transferred to the RA from the floppy disk device 126.
It is loaded into the system area 124A of M124. Thereafter, one or more necessary processing programs among the various processing programs stored in the floppy disk device 126 are loaded into the program area 124B of the RAM 124 and executed by the microprocessor 120. Data that is being processed is temporarily stored in the work area of the RAM 124. The processing result data is finally transferred to and stored in the floppy disk device 12f3. ROM1
22 stores dot patterns such as letters, numbers, and memories.

The CRT display device rFI 128 is used to display various messages for interaction with the operator, a foreign object map, and other data, and the display data is developed into a bit map in the video RAM 138. A video controller 140 controls writing and reading of the video RAM 13B, and also generates a video signal according to a dot pattern. This video controller 140 is the interface circuit 14
2 to the system bus 132.

The X-Y plotter 127 is used to print out foreign matter maps and the like, and is connected to the system bus 132 via a plotter controller 137.

Next, automatic foreign matter inspection processing will be explained with reference to the flowchart shown in FIG.

With the wafer 30 set on the rotation stage 22, when the operator commands the start of inspection from the keyboard 130, the automatic inspection processing program loaded from the floppy disk device 126 into the program area 124B of the RAM 124 starts running.

First, the microprocessor 120 processes
A storage area (see FIG. 2) for buffering data, counters, and test data is secured in the RAM 1201 (step 200).

1'', a conceptual diagram of the table (created in the table area 124+)) is shown in FIG. It consists of information on its type or nature (investigated by visual observation) and size.

Next, the microprocessor 120 sets motor control information for positioning the rotary stage 22 to the initial position (x=0.0=0) in the internal register of the interface circuit 108 (step 205). According to this motor control information, the motor controller 116 controls the motor 14.
．． 24 to move each stage to its initial position.

　　.

Microprocessor 120 generates a dot pattern of the wafer contour image and sequentially transfers it to video controller 140 through interface circuit 142 (step 21O). The video controller 140 sequentially loads the transferred dot patterns into the video RAM 138,
In parallel, the contents of the video RAM 13 B are sequentially read out, converted into video signals, and supplied to the CRT video display device 128. Thus, a wafer contour image with the orientation flat facing downward is displayed on the screen of the CRT display device 128.

Next, the microprocessor 20 instructs the motor controller 16 to start scanning through the interface circuit 108 (step 215).

Upon receiving this instruction, the motor controller 16 instructs the motor 4 to perform the above-mentioned spiral scan at a constant speed.
．． 24. Further, the microprocessor 120
P counter 124 K of RAM 1241-? = 1 &
-tz,y ht7>Iga, 272□8,.
: From the start of scanning - After a certain period of time, the micro program
□ The processor 120 periodically updates the contents of a particular register in the interface i circuit 108, i.e., the position Eex* 0v-v-V
h, L/S tLt Lt, M lnl tract,. 26
Y: Takes in the level comparison result code and the level comparison result bit of the level comparison circuit 103, and stores it in the RAM 12.
4j- to the human buffer 124c (step 2
20).

During one rotation of the wafer 30, the electrostatic field ii1 changes (j/
A total of 53 output signal levels change as shown in the waveform diagram of FIG. 7, for example. That is, when the contour of the wafer 30 exists directly on the static 1L bt displacement meter 53, the output level is higher than the threshold of the level comparison circuit 103;
When the electrostatic field at the zero orientation flat portion passes through the displacement meter 53, the output signal level decreases significantly. Level comparison circuit 1
03 is a coincidence signal of logic "1" when the level difference between the output signal of the capacitance displacement meter 53 and the threshold value is within a predetermined range, that is, when the end of the orientation flat passes the capacitance displacement meter 53. Output.

Now, the microprocessor 120 determines whether the fetched comparison result bit of the level comparison circuit 103 is "B" (step 225). If the determination result is No, it returns to step 220 and waits for the next register read timing. , if the determination result is YES, it is determined whether the value in the P counter 124 is 1 (step 230).The determination result is N.
If O, the microprocessor 120 writes information on the rotational direction position 0 stored in the large force buffer 124C to the offset angle register 124J (step 235).
), the P counter 124K is decremented (step 240), and the process returns to step 220.

If the determination result in step 230 is YES, the microprocessor 120 executes a specific calculation using the rotational direction position θ stored in the large cover sofa y124 and the rotational direction position θ stored in the offset angle register 124J. By this, the offset angle is determined and written to the offset angle register 124J (step 245).
).

This offset angle will be explained with reference to FIG.

The rotational direction 16 when the end of the orientation flat of the wafer 30 passes directly under the electrostatic field I displacement meter 53 and the level comparison circuit 103 outputs a -. signal is 01102. The rotational direction position θ3 when the center point of the orientation flat passes directly under the capacitance displacement J1103 is an intermediate value between 01 and 02, and is 71 in step 245. If the offset angle with respect to the rotation stage 22 is 0, then 03 is O,! The digit 16 of the electrostatic field displacement d153 is determined so that: Therefore, 03 is the offset angle itself.

Step 1: Finish the offset angle detection process as described.
Then, the process proceeds to step 260 and subsequent steps for actual foreign matter inspection.

The microprocessor 120 sends motor control information to the motor controller 11 via the interface circuit 108 for rapidly moving the scanning point to the inspection starting position.
6 (step 260). The motor controller 116 drives the stamping motor 14 at high speed to rapidly move the X stage 10 to the inspection start position, and after reaching the inspection start position, the stamping motor 14 is driven to perform normal X direction feeding for scanning. Drive the motor 14.

After this positioning operation, microprocessor 120:
Position 0. Comparison result code of X and level comparison circuit 102 (
L code) is fetched from the interface circuit 108 and written into the power buffer 124C (step 265).
.

The microprocessor 120 reads the X-direction peer 16
The end of scanning is determined by comparing X with the inspection path r position (step 270). If the result of this determination is NO (in the middle of the test), the microprocessor 120 performs a zero determination of the loaded L code (step 275). If L=000, there is no foreign object at the scanning position 1H. L≠000
If so, a foreign object exists.

If the determination result in step 275 is YES, step 26
Return to 5. If the determination result in step 275 is NO, the microprocessor 120 subtracts the offset angle stored in the offset angle register 124J from the rotational direction 1nO stored in the manual buffer 124C in °C to correct the offset angle. Find the N rotation direction position,
The corrected rotational direction position 0'' is the large cover, Fa 124C.
(step 280).

The second microprocessor 120 is a large Kahasof 1124
The position information (x, 0') stored in C is compared with the position information of other detected foreign objects stored in the table 150 (the rotation direction A device has been supplemented) (step 285). .

If a match is found in this positional comparison, the current foreign object can be considered to be the same as the other foreign object detected in II, so the process returns to step 265.

If the position comparison does not match, it can be assumed that a new foreign object has been detected. Therefore, the microprocessor 120 uses the RAM
The N counter 124E of 1241 units is incremented by 1 (step 290).

Then, the position information of the foreign object in the power buffer 124C and the L
The code (size information) is included (step 295).

The microprocessor 120 also sends dot pattern data corresponding to the size information (L code) of the foreign object to R.
The information is read from the OM 122 and transferred to the video controller 140 together with the address information of the video RAM 13B corresponding to the position information of the foreign object, and written into the video RAM 13B (step 297). Through this process, the detected foreign object is displayed on the screen of the display device 12B as a pattern unique to its size. Similar processing is repeated until the scanning of the wafer 30 is completed.

As described above, the wafer contour image is displayed in a fixed orientation such that the orientation flat is on the do side, but this orientation corresponds to the case where the offset angle is 0.

On the other hand, the rotational direction position of the foreign object is corrected according to the offset angle so as to correspond to the actual position of the wafer (2).

Therefore, a foreign matter map with a fixed orientation representing the actual foreign matter distribution on the wafer 1- is displayed on the screen.

When it is determined in step 270 that scanning has ended, the master 12
0 sends a scan stop +L- instruction to the motor controller 118 through the interface circuit 108 (step 300). In response to this instruction, motor controller 116 stops driving motor 14.24.

Next, the microprocessor 120 refers to the table 150 and determines the total number of foreign objects with an L code of 12, TL1. code L
The total number of foreign objects with a code L of 32 is 111 number TL2, the total number of foreign objects with a code L of 72 is 113)L, and the data of the total number of foreign objects is stored in the registers 124F and 124G of the RAM 124+-.
, 1241-1 (step 305). Then, the stored contents of the table 150 and the total foreign matter data are added to the wafer number and stored in the floppy disk device 126.
and stored therein (step 310).

I won't ask for details, but floppy disk device 1
The foreign matter inspection result data can be read out from 26, transferred to the plotter controller 137, and the foreign matter map, foreign matter total data, wafer number, etc. can be printed out by the X-Y plotter 127.

In addition, the automatically inspected wafer is placed on the rotary stage 32, the table 150 for the wafer is loaded from the floppy disk device 126 to the RAM 124, 11 visual observations of each foreign object on the wafer are performed, and the observation results are registered in the table 150. However, it is also possible to store the table 150 in the floppy disk 3a 12B at the end of the visual observation.

Although the embodiments of the present invention have been described above, the present invention is not limited thereto (and can be implemented with appropriate modifications).

For example, a sensor for detecting the orientation flat of a wafer is
In addition to the electrostatic displacement sensor 41, it is also possible to use an optical sensor.

The means for determining the offset angle from the output signal of the orientation flat detection sensor and the means for compensating the foreign object position according to the offset angle may be configured by hardware, and such hardware can be easily constructed by a person skilled in the art. , can be easily realized based on the explanation of the above embodiments.

Instead of a photomultiplier, other suitable photoelements can be used.

It goes without saying that the flow of the inspection process described above is merely an example, and may be modified as appropriate.

Furthermore, the present invention is also applicable to similar wafer foreign matter inspection apparatuses that utilize light beams other than polarized laser light.

[Effects of the Invention] As described below, according to the present invention, there is provided a wafer foreign matter inspection device that detects foreign matter on the surface of a wafer placed on a rotation stage while scanning the surface of the wafer with a spiral cane. an offset angle detection means for detecting the offset angle of the wafer of the rotation stage 1t with respect to the rotation stage, and a rotational direction position of the detected foreign object according to the offset angle detected by the offset angle detection means 1r: a position correction means for generating a foreign matter map by plotting the foreign matter after correction+E by the position line IF means on a wafer contour image in a fixed orientation; and means for outputting the foreign matter map generated by the means. is provided.

Therefore, when mounting a wafer, it is possible to obtain foreign object position information that removes the influence of angular variations and a foreign object map with a fixed orientation that represents the actual foreign particle distribution on wafer I-. It becomes possible to manage or process information on the location of foreign objects all at once, regardless of the location, and
Effects such as ease of comparison of foreign matter maps with standard wafers or other wafers can be obtained.
i

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the optical system etc. of the wafer foreign particle inspection apparatus according to the present invention, Fig. 2 is a schematic block diagram showing the signal processing and control system of the wafer foreign particle inspection apparatus, and Fig. 3 is an explanation of wafer scanning. Figure 4 is a graph showing the relationship between the particle size of foreign matter and the output signal of the photomultiplier, and the relationship with the threshold value for level comparison, and Figure 5 is the concept of a table related to inspection processing (1 figure,
FIG. 6 is a flowchart of the inspection process, and FIG. 7 is a waveform diagram of the output signal of the electrostatic customer displacement meter. ...DC motor, 30...Wafer, 36
．． 38... S polarized laser oscillator, 50... detection system,
52... Microscope, 53... Electrostatic field h1 displacement meter, 72
...Slit, 86...S polarization cut filter, 9
0... Photomultiplier, 100... Amplifier, l
02.103...Level comparison circuit, 104...Data processing system, 108...Interface circuit,
tte...Motor controller, 117...Solenoid driver, 120...Microprocessor, 12
2...ROM, 124...RAM, 12B...floppy disk device L127...X-Y plotter,
128... CRT display device, 130... Keyboard, 138... Video RAM, 150... Table.

Claims (3)

[Claims] (1) In a wafer foreign matter inspection device that detects foreign matter on the surface of a wafer placed on a rotating stage while spirally scanning the surface of the wafer, the offset angle of the wafer on the rotating stage with respect to the rotating stage is determined. an offset angle detection means for detecting an offset angle; a position correction means for correcting the rotational direction position of the detected foreign object according to the offset angle detected by the offset angle detection means; A wafer foreign matter inspection apparatus comprising: means for plotting corrected foreign matter to generate a foreign matter map; and means for outputting the foreign matter map generated by the means. (2) The means for detecting the offset angle includes a sensor for detecting the orientation flat portion of the wafer on the rotation stage, a means for comparing the output signal of the sensor with a predetermined threshold value, and a coincidence signal from the means. Claim 1, further comprising means for reading the rotational direction position of the rotary stage when the rotational stage is output, and means for determining the offset angle from the rotational direction position read by the means. Wafer foreign matter inspection equipment. (3) The wafer foreign matter inspection apparatus according to claim 1, wherein the means for outputting the foreign matter map is a display device.