JPS6211140A - Apparatus for inspecting foreign matter - Google Patents

Abstract

PURPOSE:To make it possible to automatically locate the foreign matter indicated in the visual field of a microscope only by the indication of the number of the foreign matter, by storing the positional information of the foreign matter detected on the basis of reflected light in the table on a memory. CONSTITUTION:A microprocessor 120 indicates the start of scanning to a motor controller 116 through an interface circuit 108 and drives a stepping motor 14 and a DC motor 24. Then, results by scanning, that is, the number, position, kind, property and size etc. of foreign matter are written in the input buffer 124C on RAM124. By indicating the number of the foreign matter written in RAM124, the positional information of the foreign matter is read and the movement of an article to be inspected is controlled so that the indicated foreign matter enters the visual field of a microscope.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a foreign matter inspection device that automatically inspects the presence or absence of foreign matter on a surface to be inspected, such as the surface of an LSI wafer. More specifically, the present invention not only irradiates the surface to be inspected with a light beam such as polarized radar light and automatically inspects the surface for foreign matter based on the reflected light, but also inspects the surface to be inspected using a microscope. The present invention relates to a foreign object inspection device that is also capable of visual observation.

[Prior Art] Conventionally, foreign matter inspection equipment for LSI wafers uses an Printed out using a Y plotter. According to such a foreign object map, the location and size of the foreign object can be known, but the nature or type of the foreign object cannot be determined.

Therefore, in order to investigate the nature or type of foreign particles, it is necessary to set the wafer after inspection on a microscope and visually observe each foreign particle. In this [-1 visual observation, it is necessary to move the object into the field of view of the microscope.
Traditionally, the positioning of a foreign object in the field of view is done by the operator (observer).
was entrusted to.

[Problem to be solved] It is time-consuming to move the target foreign object into the field of view of the microscope, and it is easy to misidentify the target foreign object with other objects, so the workability of visual inspection is reduced. Evil (, also uncertain.

[Object of the Invention] In view of the above-mentioned problems, an object of the present invention is to provide a foreign matter inspection device that improves the workability and reliability of visual observation.

[Step F for Solving the Problems] In order to achieve such an objective, in this invention, based on the reflected light from the surface to be inspected that has been irradiated with a light beam, In a foreign object inspection apparatus configured to be able to automatically detect foreign objects and visually observe the surface to be inspected using a microscope, information on at least the position of foreign objects detected based on the reflected light is stored in a memory in correspondence with each foreign object. means for specifying any foreign object detected based on the reflected light; means for reading position information corresponding to the specified foreign object from the memory; and according to the read position information, Is the specified foreign object within the field of view of the microscope? and means for controlling the relative position of the inspection surface and the microscope.

[Function] Since the designated foreign object is automatically and reliably positioned within the field of view of the microscope, the workability and reliability of visual observation are greatly improved.

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

FIG. 1 is a simplified schematic diagram showing the configuration of the optical system and other parts of the wafer foreign matter inspection apparatus according to the present invention. Second
The diagram shows the signal processing and control system of the device! It is a factor.

First, in FIG. 1, reference numeral 10 denotes an X stage supported by a base 12 so as to be slidable in the X direction. This X stage 1
A screw 16 directly connected to the four-rotation shaft of the stepping motor 14 is screwed into the stepping motor 1.
4, 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 position X of the X stage 10 in the X direction.

An X stage 20 is attached to the X stage IO so as to be movable in the Z direction. The moving P stage is omitted in the figure. A rotary stage 22 on which a wafer 30 as an object to be inspected is placed is rotatably supported on the X stage 20 . This interpolation stage 22 is operated by a DC motor 2
4 are connected and can be rotated by operating them. This DC motor 24 has a built-in rotary encoder that outputs a hood signal corresponding to its rotational angular position O.

Note that the wafer 30 is positioned and fixed on the rotation stage 22 by negative pressure suction, but means for this purpose are omitted in the figure.

This foreign matter inspection device uses polarized laser light to
This is a device that automatically inspects foreign objects on wafer 30.
The upper surface (surface to be inspected) of is irradiated with S-polarized laser light.

For that purpose, S-polarized laser oscillators 32, 34, 36, 3
8 is provided.

A pair of S-polarized laser oscillators 32 and 34 generate S-polarized laser light with a wavelength of λl, for example, with a wavelength of 830.
This is a 0 angstrom 11 conductor laser oscillator.

The S-polarized laser beam is applied to the wafer surface from the X direction, for example, by 2
Irradiated at an illumination angle of °.

Since the irradiation angle is thus small, when a beam of S-polarized laser light having a circular cross section is irradiated, the spot on the wafer surface extends in the X direction, making it impossible to obtain a sufficient irradiation density. Therefore, in this embodiment, a cylindrical lens 40.42 is arranged in front of the S-polarized laser oscillator 32.34, and the S-polarized laser beam is turned into a beam with a flat cross-sectional shape collapsed in the Z direction. The irradiation density is increased by emitting one beam and making the spot shape close to a circle.

The other S-polarized laser oscillator 36,38 has an S-polarized laser oscillator with wavelength λ2.
It generates polarized laser light, for example, the wavelength is 6330.
This is an Angstrom He-Ne laser oscillator. The S-polarized laser beam is transmitted through a cylindrical lens 44.48
After narrowing down in the Z direction, for example, 2 degrees from the Y direction! i (irradiated onto the wafer surface at one angle of incidence.

If the surface of the wafer is microscopically smooth before irradiation, the reflected laser light of the S-polarized laser light irradiated onto the wafer surface contains only the S-polarized light component. For example, if a pattern exists and the temperature is .degree. C., it is microscopically considered to be a smooth surface, and therefore the reflected laser beam can be considered to have only an S-polarized component.

On the other hand, if a foreign substance is present on the wafer surface, the irradiated S-polarized laser light is scattered and the polarization direction changes because the surface of the foreign substance generally has minute irregularities. As a result, the reflected laser light contains a considerable amount of P-polarized light component in addition to S-polarized light component.

Due to this phenomenon, the P contained in the reflected laser light
Based on the level of the polarized light component, the presence or absence of a foreign object and the size of the foreign object are detected. This is the detection principle of this foreign object inspection device.

rsf and see FIG. The reflected laser light from the S-polarized laser light irradiation area of the wafer 30 enters a common optical system of the detection system 50 for detecting foreign matter according to the above principle and the microscope 52 for visual observation of the wafer. 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 H-view observation.

The ijf viewing light emitted from the lamp 70 illuminates the wafer surface through the half mirror 56 and the objective lens 54.
1 will be explained.

The visible reflected light that has entered the microscope 2 side via the prism 60 passes through a 60-degree prism 62, a field lens 64, and a relay lens 66 in this order, and enters an eyepiece 68. Therefore, the wafer surface can be viewed from the eyepiece 68.
It can be observed visually at a magnification as large as 1]. In this case, the field of view includes the S-polarized laser beam irradiation area on the wafer surface.

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 two apertures 4 provided in the slit 72.
A and 74B, the light reaches a dichroic mirror 76 for wavelength separation, and is separated into a reflected laser beam of wavelength λ and a reflected laser beam of wavelength λ2.

The separated reflected laser beam of wavelength λ is passed through a sharp cut filter 78 and an S polarization cut filter (polarizing plate) 8.
0 and only its P polarized component is extracted. The extracted P-polarized laser beam is incident on the separation mirror 82, the portion that has passed through the aperture 4A of the slit 72 is incident on the photomultiplier 84A, and the portion that has passed through the aperture 4B is incident on the photomultiplier 84B.

Similarly, the wavelength-separated reflected laser beam of wavelength λ2 is S
The light is passed through a polarization cut filter (polarizing plate) 86, and only the P polarized light component is extracted. The extracted P-polarized laser beam is incident on the separation mirror 88, and the portions that have passed through the apertures 4A and 74B of the slit 72 are photomultipliers 90A, respectively.

90B.

Each photomultiplier 84A, 84B, 90A.

90B outputs a detection signal having a value proportional to the amount of incident light. As described later, the detection signals of photomultipliers 84A and 90A are added together, and similarly, the detection signals of photomultipliers 84B and 90B are added together.

As described later, the presence of a person in the S-polarized laser beam irradiation area is determined based on the level of this added signal, and if a foreign object is present, the particle size of the foreign object is determined from the signal level. be done.

Here, the 5I4 object inspection is performed while rotating the wafer 1 and feeding it in the X direction (radial direction) as described above. According to such movement of the wafer 30, as shown in FIG. 3, the S-polarized light irradiation area 30A moves in a spiral pattern from the outside toward the center of the wafer 130 on the north surface. The field of view of the apertures 4A and 74B of the slit 72 is the S-polarized laser beam
It is located within the radiation area 30A. That is, the wafer is scanned spirally.

Further, the fields of view 74a and 74b of the apertures 4A and 74B of the slit 72 on the wafer are as shown in FIG. Each dimension in this figure is, for example, l, = 2X
12-α, and each aperture is spaced by α in the direction perpendicular to the scanning direction (0 direction), that is, in the X direction. Further, ll is larger than the feeding pitch of the wafer in the X direction, that is, in the radial direction. Therefore, the wafer will be partially scanned.

In this way, the aperture of the slit 72 is divided into two,
The reason why each field of view is shifted in the X direction is as follows.

The signal output from the photomultiplier includes, in addition to signal components related to foreign matter, background noise determined by the state of the surface to be inspected. In order to increase the signal-to-noise ratio of the signal and enable the detection of minute foreign objects, it is necessary to reduce the aperture of the slit. However, when there is only one aperture, if the aperture is small, the scanning line pitch (feeding pitch in the X direction) must be made small, which increases the time required to scan the entire front surface of the subject. Therefore, in this embodiment, as described in 11'1, two apertures (generally, a plurality of apertures) are provided, and the field of view of each is shifted in the X direction to expand the overall field of view in the X direction. The aim is to shorten the inspection time when the time is reduced by 1 minute.

In addition, in order to eliminate detection errors due to the polarity of foreign objects, the outputs (, i) of each photomultiplier that detects scattered light irradiated from different directions are added, as will be described later.

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

The output signals of the photomultipliers 84A and 90A are summed and amplified by a summing amplifier 100, and then sent to a level comparison circuit 1.
02 is input. Similarly, photomultiplier 84B
, 90B are summed and amplified by a summing amplifier 104 and input to a level comparison circuit 106.

Here, there is a relationship as shown in FIG. 5 between the particle size of the foreign matter of the sea urchin pigeon and the output level of the photomultiplier 84.90. In this figure, L/, L
2. LJ is a threshold value of the level comparison circuits 102 and 106.

The level comparison circuits 102 and 106 compare the level of each input signal' with each threshold value, and send out an output 4f;''J corresponding to the logical level threshold value according to the comparison result. That is, the threshold value L/, L2 Output signal O1 corresponding to .LJ
The logic level of + 02 t Oa becomes "1" when a signal with a level equal to or higher than the threshold is input, and becomes "0" when the input signal level is below the threshold.
For example, if the input signal level is less than the threshold L/, all output signals will be "0", and if the input signal level is greater than or equal to the threshold L2 and less than the threshold L3, the output signals will be "0".
1”, 03 becomes “0”.

Thus, the output signal O1+02+OJ is a binary code indicating the result of level comparison of the input signals.

The output signals of the level comparison circuits 102 and 106 are wire-ORed with the corresponding signals, and are input as code L (binary code with 0 as the least significant bit) to the interface circuit 108 of the data processing system 118.

This interface circuit 108 receives a signal i-; (binary code) indicating information about the rotational angular position O and the X direction (radial direction) position X at each time point from the encoder and the linear encoder. 11
Input via 0.112. These input codes are
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 108, there is also a register in which control information for the stepping motor 14 and the DC motor 24 is set by the data processing system 118.

According to the 1 and 11 information set in this register, the stepping motor 14 is controlled by the motor controller 116.
, drive control of the DC motor 24 is performed.

Data processing system 118 includes microprocessor 12
0. It consists of a ROM 122, a RAM 124, a floppy disk device 126, an X-Y plotter 127, a CRT display device 128, a keyboard 130, and the like. 132
is the system bus, and the microprocessor 120, R
OM 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 foreign object inspection device is started, the operating system is transferred from the floppy disk device 128 to the RAM 12.
4 is loaded into the system area 124A. 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 1 24 and executed by the microprocessor 120. Data that is being processed is temporarily stored in a work area of the RAM 124. The processing result data is finally transferred to and stored in the floppy disk device 126.

The ROM 122 stores dot patterns of letters, numbers, memories, etc.

The CRT display device 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. 140 is a video controller, and video RAM1
In addition to controlling the loading and reading operations of 38, it also performs operations such as video borrowing and cursor pattern generation according to dot patterns. The video controller 140 is connected to the system bus 132 via an interface circuit 142. A cursor address pointer 140A for controlling the cursor address is connected to the video controller 1.
40, but this pointer is located on the keyboard 1.
30 and is incremented or decremented according to cursor control signals from microprocessor 12.
Accessible by 0.

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, foreign matter inspection processing will be explained with reference to the flowchart in FIG. Here, automatic inspection of foreign objects,
Although the operator specifies jobs such as visual observation and printing, this is just one example.

When the operator commands the start of inspection from the keyboard 130 with the wafer 30 set at a predetermined position on the rotation stage 22, the inspection processing program is transferred from the floppy disk device 126 to the program area 124 of the RAM 124.
It is loaded onto B and starts running.

First, the microprocessor 120 performs initialization processing. Specifically, the X stage 10 and the rotation stage 22
Motor control information for positioning the motor to the initial position is set in an internal register of the interface circuit 108. According to this motor control information, motor controller 1
1B controls the stepping motor 14 and the DC motor 24 to move each stage to its initial position. Furthermore, the microprocessor 120 reserves storage areas (see FIG. 2) for tables, counters, inspection data buffers, etc., which will be described later, on the RAM 124 (these storage areas are cleared).

] Yuji table (created in table area 124D)
A conceptual diagram of this is shown in Fig. 7. Each entry in this table 150 includes a foreign object number (detection order), a foreign object position (detection order), and a foreign object position (detection order).
It consists of information on the detected scanning position (X, θ), its type or nature (investigated by visual observation), and size.

After the initialization, a job menu is displayed on the CRT display device 128, and a command 24 from the operator is displayed.
The system waits for the program to be specified.

The flow of processing when an "automatic inspection" job is designated will be described with reference to the flowchart in FIG. 6(A).

When the autotest code is entered into microprocessor 120 through keyboard 130, microprocessor 120 begins the autotest process. First, the microprocessor 120 instructs the motor controller tte to start scanning through the interface circuit 108 (step 210). Upon receiving this instruction, the motor controller 116 controls the stepping motor 14. DC motor 24
to drive.

The microprocessor 120 includes an interface circuit 1
08 specific internal register contents, i.e. wafer 3
0 scanning position X+ 0 code and level comparison circuit 1
The input data consisting of the code L, which is the result of the level comparison between 02 and 106, is taken in and written into the large power buffer 124C of the RAM 12i (step 215).

The microprocessor 120 determines the end of the scan by comparing the captured scan position information with the position information of the end position of the scan (step 220).

If the result of this determination is No (in the middle of scanning), the microprocessor 120 performs a zero determination of the loaded code L by 1.
Yes (step 225). If L=000, no foreign matter exists at that scanning position.

If L≠000, foreign matter exists.

If the determination result in step 225 is YES, step 21
Return to 5. If the determination result in step 225 is NO, the microprocessor 120 carries out the acquired position information +v(X
, 0) and the position information (X.

0) (step 230).

If the position information matches, the current foreign object can be considered to be the same as another foreign object, and the process returns to step 215.

If the location information does not match, it can be assumed that a new foreign object has been detected. Therefore, the microprocessor 120
The counter N, which is the area 124E secured in the RAM 124-1, is incremented by 1 (step 235).
). Then, the position information (X, θ) of the foreign object and the hood L (as particle size information) are written in the Nth entry of the table 150 (step 240).

Similar processing is repeated until the scanning of the wafer 30 is completed.

If it is determined in step 220 that the scanning line is r, the master 12
0 sends a scanning stop instruction to the motor controller 11B through the interface circuit 108 (step 250). In response to this instruction, motor controller 1
16 stops driving the stepping motor 14 and the DC motor 24.

Next, the microprocessor 120 refers to the table 150 and calculates the total number of foreign objects with code L of 12 TL/1 code L.
The total number of foreign objects T L 2 with a code L of 32 and the total number TLJ of foreign objects with a code L of 72 are calculated, and the data of the total number of foreign objects is stored in the specific areas 124F, 124G, 12 on the RAM 124.
4H is counted (step 251). Then, the description/IQ contents and total foreign matter data of the table 150 are transferred to the floppy disk device 126 with a wafer number added thereto and stored therein (step 252).

This completes the automatic inspection job, and the job menu is displayed on the CRT display device 128.

Next, the process flow of "11 visual observation" - Figure 6 (B)
This will be explained with reference to the flowcharts in FIGS. 6(E) to 6(E).

Visual observation includes a sequential mode, a number specification mode, and a cursor specification mode, depending on the method of specifying the four objects to be observed, which can be specified using the keyboard 130.

When the visual observation job and mode are specified, the microprocessor 120 causes the 70-mp disk device 126 to transfer the dot pattern data of the wafer outline image to the video RAM 138 by DMA (step 285).

Is this transfer start-up controlled by the micropro sensor 120? +', but subsequent transfer control is performed by the video controller 140 and floppy disk controller 13B.
carried out by The dot pattern data in the video RAM 138 is sequentially read out by the video controller 140, converted into a video signal, and sent to the CRT display device 128 for display.

Next, the microprocessor 120 reads the stored contents of the table 160 and the total number of foreign objects data stored in the floppy disk drive 12B, with the falsification of the wafer to be observed (input from the keyboard 130 when selecting a job) added. , and populates the corresponding area of the RAM 124 (step 290).

The microprocessor 120 sequentially reads the position information and size information (L code) of each foreign object from the table 150 of the RAM 124-1, reads the dot pattern data corresponding to the L code from the ROM 122, and stores the dot pattern data of the video RAM 138 corresponding to the position information. It is transferred together with the address information to the video controller 140 and written into the video RAM 138 (step 29S). Through this process, the foreign object map stored in the table 150 is displayed on the screen of the CRT display device 128.

Next, the microprocessor 120 instructs the motor controller 116 to position the scanning position to the initial position via the interface circuit 108 (the stepper 3
00). The following processing differs depending on the specified mode.

If sequential mode is specified, the microprocessor 12
0 is 1 in counter M (area 124J of RAM 124)
(step 320), and the data of the foreign object (the foreign object detected at number M [1) stored in the Mth entry of the table 150 is read out (step 325). Then, control information for moving the scanning position to the position corresponding to the position end +U (x, 0) is sent to the motor controller 11B via the interface circuit 108.
(step 330). When the stepping motor 14, DC motor, and 24 are controlled by the motor controller 116 and the scanning position is determined, the foreign object Mal1 of interest is naturally located at the center of the field of view of the optical microscope 52.

The microprocessor 120 generates a foreign object pattern corresponding to the L code of the foreign object number M "1" and the second foreign object pattern (P is the RAM 12
The foreign object pattern corresponding to the foreign object code (the value of the counter P) is read out from the ROM 122 in the area 124 of No.
The pattern of the I-th foreign object remains unchanged, the pattern of the M-th person is inverted, and is sequentially transferred to the video controller 140 along with the address information, and these patterns are transferred to the video controller 140.
Write to the corresponding AM address (step 335)
. Now, only the foreign object numbered M-1 on the foreign object map displayed on the screen of the CRT display device 128 is displayed as an inverted pattern, and is visually distinguished from other foreign objects.

The microprocessor 120 includes an interface circuit 1
08, and compares it with the position information of the Mth person to determine whether the positioning is complete (step 340). Once the positioning is complete, microprocessor 120 transfers a message to video RAM 138 indicating the observation i+J function and CRT display device 128.
(step 345). Then, it waits for a key input (step 350).

The operator visually observes the foreign object, identifies the nature or type of the foreign object, and inputs a code for the nature or type from the keyboard 130. In practice, by specifying a visual observation job, the CRT display device 1
On the screen 28, a table showing the properties or types of foreign substances and their occurrence is displayed, and the corresponding number in the table is input.

If the input code is a code for the nature or type of a foreign object (step 352), the microprocessor 120 writes that code into the entry number M "1" in the table 150 (step 355). , step 355 is skipped.

Next, the microprocessor 120 operates counters M, P
is incremented by 1 (step 360), and a comparison is made between the counter M and the counter N (this value is the total number of 41 foreign objects detected) (step 365).
). If M<N, the process returns to step 325.

Also, if M≧N, table 150 on RAM 138
In step 3, the memory contents and the total number of foreign particles are transferred to the floppy disk device 126 along with the wafer number>f.
70), returns to the job menu screen state.

In this way, in the sequential mode, the foreign objects to be observed are generated in ascending order as information for determining the object, and the specified foreign object is automatically positioned in the field of view of the microscope based on the information. :Determined.

On the other hand, if the number designation mode is designated, the microprocessor 120 waits for the operator to input a foreign object number (step 410). When a key input is made, it is determined whether the input code is a foreign object number (step 415)
. If it is not a foreign object number, wait for key input.

When the foreign object number is keyed in, the microprocessor 12
0, the foreign object number is placed in the counter M (step 420), and the process proceeds to step 325.

Thereafter, in step 357, the value of the counter M is changed to the value of the counter P.
In the next step 400, it is determined whether the current mode is a number designation mode or a cursor designation mode. Here, since the mode is for specifying the number of characters, the process returns to step 410.

In the same way as above, by key-inputting the foreign object number,
The specified foreign object is automatically positioned approximately at the center of the visual life of the microscope 52, 1'A visual observation is performed, and the result of the visual observation is entered into the corresponding entry in the table 150.

In this way, in the number designation mode, when the operator inputs the foreign material layer as foreign material designation information, the foreign material with that number is automatically positioned in the field of view of the microscope.

Although not shown in the flowchart, if the end r key on the keyboard 130 is input at any time, the number designation mode ends, and after the process of step 370, the job menu screen is returned to.

The cursor specification mode will be explained. In the cursor specification mode, the operator operates the cursor operation keys provided on the keyboard 130 to
Cursor address pointer 1 through cursor control signal
40A, move the cursor displayed on the screen of the CRT display device 128 to the position of the target foreign object also displayed on the screen, and press the cursor read key on the keyboard 130 to observe it. Specify the foreign object that should be removed.

In this mode, the microprocessor 120 waits for a key input (step 430), and when a key input is made, it determines whether it is a code for a cursor read key (step 435). If the determination result is NO, the process waits for key input.

If the determination result is YES, the microprocessor 120
reads the contents (cursor address) of the cursor address pointer 140A (step 440). and,
The cursor address is converted into a corresponding scanning position, that is, a foreign object position (step 445).

Next, the table 150 is searched, the obtained foreign object position is compared with the position of each foreign object stored in the table 150, the nearest foreign object is searched (step 450), and the number of the foreign object is set in the counter M. (Step 455)
. Then, the process advances to step 325.

In this way, the foreign object designated by the cursor is automatically positioned in the field of view of the microscope, and the observation result is entered into the corresponding entry in the table 150.

If the end key (not shown) on the keyboard 130 is pressed, the process branches to step 370, and after the step 370 is completed, the job selection screen is displayed.

Through the visual observation, a table is obtained in which the results of the visual observation and the results of the automatic inspection are integrated.

This table allows the results of automatic inspection and visual observation to be collectively managed.

In addition, in the 1-view observation, the foreign object being observed is displayed as an inverted pattern on the CRT display device 128 on the screen surface, and on the foreign object map marked 1, so the operator (observer) can This can be easily confirmed using the foreign body map. This is particularly effective in J- for preventing erroneous foreign object designations when visual observation is performed in the number designation mode while referring to the printed foreign object map or the contents of the table 150.

If "print" is specified on the job selection screen, the test results can be printed out from the X-Y plotter 127.

When printing is specified, as shown in FIG. 6(F),
Microprocessor 120 reads wafer contour image data from floppy disk device 126 and transfers it to the plotter controller (step 465).

Next, the microprocessor 120 sequentially reads out the stored contents of the table 150 stored in the floppy disk device 126 and the data on the total number of foreign objects, to which the number of the wafer to be printed (input from the keyboard 130 when selecting a job) is added. , to the block controller 137 (step 470).

In this way, the foreign matter map, table contents (table), foreign matter total number data 1, and wafer number are printed by the X-Y plotter 127.

When printing is finished, the screen returns to the job selection screen.

Although one embodiment of the present invention has been described above, the present invention is not limited thereto, and can be implemented with appropriate modifications.

For example, it is not necessary to have two crabs in which the scanning position of the detection system is always within the field of view of the microscope (, it is sufficient if the scanning position and the field of view can maintain a constant positional relationship. (!jL, J
)' J Example makes it easy to perform processes such as identifying foreign objects during visual observation.

Instead of the photomultiplier, other suitable photoelements Y can be used.

The scanning is not limited to spiral scanning, but may be linear scanning, for example. (ji L, since linear scanning stops at the scanning end, the scanning time tends to increase. Also, when scanning a circular limb inspection surface such as a wafer, the position control of scanning ☆: lf is complicated. Therefore, for foreign object inspection such as wafers, helical scanning is generally advantageous.

The slit may have one aperture, or three or more apertures.

Furthermore, it goes without saying that the present invention can be similarly applied to a device for inspecting foreign matter on surfaces to be inspected other than wafers. Further, the present invention can also be applied to a similar foreign matter inspection device that uses a light beam other than a polarized laser beam.

[Effects of the Invention] As described above, the present invention is capable of automatically detecting a foreign object on a surface to be inspected based on the reflected light from the surface to be inspected that has been irradiated with a light beam; A foreign object inspection device configured to allow visual observation of an inspection surface using a microscope, comprising: means for storing in a memory information on at least the position of a foreign object detected based on the reflected light in association with each foreign object; means for specifying an arbitrary foreign object, means for reading position information corresponding to the specified foreign object from the memory, and according to the read position information, the specified foreign object enters the field of view of the microscope. The apparatus further includes means for controlling the relative position of the surface to be inspected and the microscope.

Therefore, according to the present invention, a designated foreign object is automatically positioned within the field of view of the microscope, and the positioning is ensured, greatly improving the workability and reliability of visual observation.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of the optical system of the foreign object inspection device according to the present invention, FIG. 2 is a schematic block diagram showing the signal processing and control system of the foreign object inspection device, and FIG. 3 is an explanation of scanning of the surface to be inspected. Figure 4 is an explanatory diagram regarding the slit aperture, Figure 5 is an explanatory diagram regarding the aperture of the slit.
The figure 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 FIGS. 6(A) to 6(F) are flowcharts showing the flow of the inspection process, FIG. 7 is a conceptual diagram of tables related to inspection processing. 10...X stage, 14...Stepping motor, 22... Rotating stage, 24... DC motor, 3
0...Wafer, 32,34.38.38...S polarization laser oscillator, 50...Detection system, 52...Microscope,
72...Slit, 76...Dichroic mirror, 80...S polarization cant filter, 82...Separation mirror, 84A. 84B... Photomultiplier, 86... S polarization cut filter, 88... Separation mirror, 90A, 90B
...Photomultiplier, 100,104...Summing amplifier, 102,106...Level comparison circuit, 108
. . . Interface circuit, 116 . . . Motor controller, 120 . . . Microprocessor, 122.
...ROM, 124...RAM112B...floppy disk device, 127...X-Y plotter, 12
8... CRT display device, 130... Keyboard, 138... Video RAM, 150... Table.

Claims (4)

[Claims] (1) In a foreign matter inspection device configured to automatically detect foreign matter on the surface to be inspected based on the reflected light from the surface to be inspected that has been irradiated with a light beam, and to visually observe the surface to be inspected using a microscope. , means for storing information on at least the position of a foreign object detected based on the reflected light in a memory in association with each foreign object; means for specifying any foreign object detected based on the reflected light; means for reading positional information stored in the memory corresponding to a foreign object from the memory; and according to the read positional information, aligning the surface to be inspected so that the designated foreign object falls within the field of view of the microscope. A foreign matter inspection device comprising means for controlling a relative position with the microscope. (2) The means for specifying the foreign object is a means for inputting information for specifying the foreign object, and the means for reading the one embodiment information is based on the input information for specifying the foreign object, 2. The foreign object inspection apparatus according to claim 1, wherein position information corresponding to the foreign object is read out from the memory. (3) The means for specifying the foreign object is a means for generating information for specifying the foreign object, and the means for reading the position information is based on the information for specifying the foreign object,
2. The foreign object inspection apparatus according to claim 1, wherein position information corresponding to the foreign object is read out from the memory. (4) The foreign object inspection device according to claim 2 or 3, wherein the information for specifying the foreign object is a foreign object number unique to the foreign object.