JPH06252230A - Method and apparatus for inspection of defect - Google Patents

Abstract

PURPOSE:To prevent foreign matter adhering to a mirror surface wafer from being erroneously judged to be foreign matter in a film formation processing in foreign matter inspection after the film formation processing. CONSTITUTION:Upon foreign matter inspection work for a mirror surface wafer 1 before film formation is applied, foreign matter inspection is executed with higher detection sensitivity (0.1mum or greater), during foreign matter inspection work for a wafer 1A after the film formation, foreign matter inspection is executed with a lower sensitivity (0.3mum or greater) than the detection sensitivity in the foreign matter inspection for the mirror surface wafer 1. The location of foreign matter (b) after the film formation processing and the location of the foreign matter (b) before the film formation processing are collated, and the foreign matter distribution before the film formation processing is subtracted from the foreign matter distribution after the film formation processing whereby foreign the matter (d) formed in the film formation processing is identified. Hereby, an ultrafine foreign matter (a) adhering to the mirror surface wafer 1 is prevented from being erroneously judged as a foreign matter (d) adhering in the film formation processing in the foreign matter inspection after the film formation processing, and hence diagnosis appraisal for the film formation process is prevented from being lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a defect inspection technique, and more particularly,
BACKGROUND OF THE INVENTION The present invention relates to an automatic defect inspection technique for foreign matter attached to a surface of an object to be inspected as a defect, which is effective for inspecting foreign matter attached to the surface of a semiconductor wafer (hereinafter referred to as a wafer) in a semiconductor device manufacturing process. Regarding things.

[0002]

2. Description of the Related Art Today, semiconductor integrated circuit devices (hereinafter referred to as IC
Say. ) High integration and miniaturization of patterns are progressing,
The line width of the circuit pattern has become about 1 μm or less. In such a situation, in order to manufacture ICs with a high yield, it is necessary to inspect foreign substances adhering to the surface of the wafer, quantitatively grasp the cleanliness of various semiconductor manufacturing apparatuses, and appropriately control the manufacturing process. There is. Therefore, conventionally, in the process of manufacturing an IC, a foreign substance inspecting apparatus is used to automatically inspect foreign substances adhering to the surface of a wafer before the process is put into operation.

Conventionally, as a foreign matter inspection apparatus used for inspecting a foreign matter on a wafer, there are used an irradiation apparatus for irradiating a laser as an inspection wave on the wafer and a detection apparatus for detecting scattered light of the laser on the wafer. And a recognition device for recognizing the position and size of the foreign matter based on the detection of the photosensor, the scattered light in the foreign matter irradiated on the wafer is detected by the photosensor, and the recognition device based on this detection signal. There is a wafer foreign matter inspection device configured to identify the position and size of the foreign matter.

When such a wafer foreign matter inspection apparatus is used to carry out a wafer foreign matter inspection, it is present on the wafer before the process to be diagnosed (or evaluated), particularly before the film forming process. Since the foreign substance that was used is a foreign substance that is not subject to diagnosis, it is necessary to exclude it, but it is extremely difficult to artificially exclude it. Therefore, conventionally, in a foreign matter inspection method using such a foreign matter inspection apparatus for a wafer, foreign matter that is not a diagnosis target is excluded by the following method.

First, a so-called specular wafer which has not been put into a semiconductor device manufacturing process is preliminarily subjected to a foreign matter inspection, and the foreign matter inspection result for this specular wafer is stored as an initial value. Then, a film forming process is performed on the mirror-finished wafer in a film forming process, and a foreign substance inspection is performed on the film-formed wafer to identify the foreign substance in the state after the film forming process.

Then, the distribution of foreign matter on the mirror surface wafer is subtracted from the distribution of foreign matter after the film forming process, and it is determined that the remaining foreign matter is the foreign matter adhered by the film forming process. Based on this determination, diagnosis or evaluation regarding the cleanliness and the like of the film forming processing apparatus used in the film forming processing step is executed.

An example of the foreign matter inspection technique for wafers is described in Japanese Patent Application Laid-Open Publication No. 54-1013.
90, 59-186324, 59-65428.
No. 55-124008, No. 62-223649.
No. 62-223650, No. 62-223651
No. 63-82348 and No. 64-3545.

[0008]

However, in the above-described conventional foreign matter inspection method for wafers, the foreign matter adhered to the mirror-finished wafer is erroneously recognized as the foreign matter adhered in the film formation process in the foreign matter inspection after the film formation process. It has been made clear by the present inventor that there is a problem that it is often judged.

As a result of various investigations regarding this problem, the present inventor has obtained the following findings. That is, the reason why the foreign matter attached to the mirror-finished wafer is erroneously determined as the foreign matter attached in the film forming process in the foreign substance inspection after the film forming process is as follows.
Ultra-fine foreign matter that adheres to the mirror-like wafer and was not recognized as a foreign matter of a size that would hinder the foreign matter inspection of the mirror-like wafer is also deposited on the fine foreign matter during the film forming process. This is because the swelled state causes the foreign matter to be detected as a foreign matter having a size that causes an obstacle in the foreign matter inspection after the film forming process.

The present invention was created on the basis of this knowledge, and the purpose thereof is that the foreign matter adhered to the mirror-finished wafer adhered in the film formation process in the foreign matter inspection after the film formation process. It is to provide a defect inspection technique capable of preventing erroneous determination as a foreign substance.

The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

[0012]

The typical ones of the inventions disclosed in the present application will be outlined below.

That is, in a defect inspection method for performing an appearance defect inspection on a semiconductor wafer that has been subjected to a film forming process, the appearance defect inspection is performed with high sensitivity on the semiconductor wafer before the film forming process is performed. The step of storing the position of the defect as the inspection result, and the appearance defect inspection of the semiconductor wafer after the film formation processing is performed after the film formation processing is performed on the semiconductor wafer after the film formation processing is performed. The process performed with low sensitivity, the position of the defect that is the appearance inspection result after the film forming process, and the position of the defect that is the appearance inspection result before the film forming process are collated, and after the film forming process, The defect distribution which is the appearance inspection result before the film forming process is subtracted from the defect distribution which is the appearance inspection result, whereby a defect formed in the film forming process is specified. It is characterized in.

[0014]

According to the above-described means, even a very small defect is recognized because a highly sensitive inspection is performed in the defect inspection of the semiconductor wafer before the film formation. Then, during the film forming process, the extremely small defects are enlarged due to the film deposition.

In the defect inspection of the semiconductor wafer after the film forming process, an inspection having a relatively low detection sensitivity which is a sensitivity for detecting only a size larger than an allowable range is performed. For this reason, the extremely small size defects detected in the defect inspection before the film formation process are not detected as defects within the allowable range. However, a defect that has grown to a size larger than the allowable range during the film forming process is detected even in the defect inspection after the film forming process.

In this way, according to the above-mentioned means,
The extremely small defects that existed on the semiconductor wafer before the film formation process and that had grown to a size outside the allowable range by the film formation process were detected as defects after the film formation process. It is possible to prevent a defect formed before the film formation process from being erroneously determined as a defect formed in the film formation process in a defect inspection after the film formation process. That is, when the defect distribution, which is the defect inspection result for the semiconductor wafer before the film formation process, is subtracted from the defect distribution, which is the defect inspection result for the semiconductor wafer after the film formation process, the microscopic defects before the film formation process are enlarged. Therefore, the enlarged micro defects before the film formation process are not erroneously determined as defects formed by the film formation.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view for explaining a method for inspecting foreign matter on a wafer which is an embodiment of the present invention. FIG. 2 is an explanatory view showing a comparative example for explaining the foreign matter inspection method for the wafer. FIG. 3 is a schematic view showing a wafer foreign matter inspection apparatus which is one embodiment of the present invention used in the wafer foreign matter inspection method.

In the present embodiment, the defect inspection apparatus according to the present invention is configured as a wafer foreign matter inspection apparatus.
This foreign matter inspection apparatus for wafers uses a wafer 1 as an inspection object.
It is configured to analyze the position distribution of foreign matter as a defect attached in the film forming process to be diagnosed and the size of the foreign matter.

This foreign matter inspection apparatus for a wafer is provided with an inspection chamber 2 which is constructed so as to form a clean atmosphere, and one side wall (hereinafter referred to as the right side) of the inspection chamber 2 is covered with a gate 3. The wafer 1 as an inspection object is installed in and out of the inspection chamber 2. A stage 4 for loading / unloading the wafer 1 is set on the right side in the inspection chamber 2, and a foreign matter inspection stage for inspecting the position and size of the foreign matter on the left side in the inspection chamber 2. 5 is set.

A holder 6 for holding the wafer 1 is installed in the inspection chamber 2 while being supported by a moving table 7. The moving table 7 is configured to move the holder 6 in the XY directions, and the moving coordinates in the XY directions are input to the controller 11 by the encoder 8.

The moving table 7 is constructed so as to be moved between the loading / unloading stage 4 and the inspection stage 5 by a feed screw device 9 driven by a motor 10, and the motor 10 is controlled by a controller 11. Is configured to. A position detector 18 is installed directly above the moving table 7 of the loading / unloading stage 4, and the detector 18 is configured to transmit a detection result to the wafer position controller 19.

A laser oscillator 12 is installed in the inspection stage 5 of the inspection room 2, and this laser oscillator 12 causes a laser 14 as an inspection light for realizing a nondestructive inspection in the inspection stage 5 via a scanning mirror 13. The surface of the wafer 1 is scanned and irradiated.

A photosensor 16 as a detection device is installed on the inspection stage 5 so as to face a laser irradiation point on the surface of the wafer 1, and the photosensor 16 irradiates foreign matter on the wafer 1 with each other. Further, the scattered light 15 of the laser 14 can be detected. The scanning mirror 13 is configured to be controlled by the foreign matter inspection controller 17, and the photosensor 16 is configured to input the detection result to the controller 17.

This wafer foreign matter inspection apparatus is a central processing unit (hereinafter referred to as CPU) including a computer and the like.
The CPU 20 is connected to the holder controller 11, the foreign substance inspection controller 17, and the wafer position controller 19. Also, CPU
A console 21 for setting desired parameters and the like, a memory 22 as a defect position and size storage unit, and an arithmetic unit 23 are connected to the unit 20, respectively, and the memory 22 and the arithmetic unit 23 are connected to a printer, an external memory, or the like. A display device 24 is connected with the output device as described above.

The memory 22 is configured to store the position and size of the foreign matter on the wafer 1 sent from the foreign matter inspection controller 17 through the CPU 20 as defect data. Further, the arithmetic unit 23 is configured to be controlled by the CPU 20 so that the foreign matter data sent from the memory 22 through the CPU 20 can be compared with each other to perform a desired arithmetic operation such as subtraction.

Next, a method for inspecting a foreign substance on a wafer according to an embodiment of the present invention will be described in the case where the apparatus for inspecting a foreign substance on a wafer according to the above configuration is used.

First, a wafer before a film forming process to be diagnosed, that is, a wafer (hereinafter, referred to as a mirror-finished wafer) 1 which has not been put into a semiconductor device manufacturing process in this embodiment is taken from a gate 3. Loading in the inspection room 2
Holder 6 being moved to unloading stage 4
Reprinted on top. At this time, the mirror-finished wafer 1 is transferred to the holder 6 with the surface (hereinafter referred to as the front surface) on the side where the film forming process is performed facing upward.

The movement coordinates of the holder 6 are input to the controller 11 by the encoder 8 and the motor 10 is controlled. Before the inspection table 7 is moved to the inspection stage 5, the position coordinates of the mirror-finished wafer 1 are read by the wafer position detector 18, and the detection result is sent to the position detection controller 19. At this time, if a target for coordinate reading is attached to the mirror-finished wafer 1 in advance, the position coordinates of the mirror-finished wafer 1 can be easily read.

When the mirror surface wafer 1 is positioned and set on the holder 6, the holder 6 holding the mirror surface wafer 1 is moved in parallel to the inspection stage 5 by the moving table 7.

When moved to the inspection stage 5, while the laser 14 from the laser oscillator 12 is scanned by the scanning mirror 13, the mirror-finished wafer 1 is moved in the XY direction by the moving table 7.
By moving in the direction, the entire front surface of the mirror-finished wafer 1 is regularly irradiated.

At this time, if a foreign matter is present on the laser-irradiated surface of the mirror-finished wafer 1, the laser 14 irradiating the foreign matter is scattered, and the scattered light 15 from the foreign matter is detected by the photosensor 16. When scattered light from a foreign object is detected,
A detection signal is input from the photo sensor 16 to the controller 17, and the output of the encoder 8 is latched in the memory 22.

At this time, since the spot diameter of the laser 14 is set to be sufficiently small, the size of the foreign matter can be detected by the number of times the scattered light 15 from the same foreign matter is detected. That is, by appropriately selecting the spot diameter of the laser 14 and the number of times of detection of the scattered light 15 that determines the size of the foreign matter, the foreign matter detection sensitivity of the foreign matter inspection apparatus for this wafer can be changed and adjusted.

In this embodiment, in the foreign matter inspection work on the mirror-finished wafer 1, the foreign matter detection sensitivity of the foreign matter inspection apparatus for this wafer is increased. That is,
The spot diameter of the laser 14 is set to be sufficiently small so that the scattered light 1 from the same foreign matter determines the size of the foreign matter.
The number of detection times of 5 is set so that the size of the very small foreign matter can also be determined. For example, the foreign matter detection sensitivity when performing the foreign matter inspection operation on the mirror-finished wafer 1 is set so that a foreign matter having a size of 0.1 μm or more is detected.

The CPU 20 creates a foreign substance distribution map 31 for the mirror-finished wafer 1 shown in FIG. 1A by image processing based on the foreign substance existence position and foreign substance size data. The image 31 is displayed on the display device 24 and the foreign matter distribution map 31 is displayed.
Are stored in the memory 22.

Here, in the foreign matter distribution diagram 31, only the position of the foreign matter a on the mirror-finished wafer 1 is displayed, and the size of each foreign matter a is not displayed. However, the position of the minute foreign substance a which does not hinder is displayed.

As described above, the mirror-finished wafer 1 on which the foreign matter distribution map 31 before the film forming process is prepared is
Through the gate 3 to the outside. The taken-out mirror surface wafer 1 is sent to a first stage film forming process which is a film forming process to be diagnosed and subjected to a predetermined film forming process.

After that, a wafer 1A having a film deposited on the front surface (hereinafter referred to as a film-formed wafer) through a film forming process to be diagnosed is loaded / unloaded from the gate 3 into the inspection chamber 2. It is transferred onto the holder 6 of the stage 4.

Subsequently, the film-formed wafer 1A is detected for foreign matter on the front side surface by the same operation as the foreign matter inspection work for the mirror-finished wafer 1 described above, and based on the data of the position distribution and size of the foreign matter. With the CPU 20, FIG.
A distribution map 32 of the foreign matter b after the film formation process shown in (b) is created by image processing, the image of this distribution chart 32 is displayed on the display device 24, and the foreign matter distribution map 32 is stored in the memory 22. Memorized in.

In the foreign matter inspection work for the wafer 1A after the film formation, the foreign matter detection sensitivity of the foreign matter inspection device for this wafer is relatively lower than the foreign matter detection sensitivity in the foreign matter inspection work for the mirror-finished wafer 1 described above. Is set to. For example, the spot diameter of the laser 14 is set to be larger than the spot diameter in the inspection work on the mirror-finished wafer 1 described above, and the number of detections of scattered light 15 from the same foreign matter that determines the size of the foreign matter is extremely small. Set to exclude.

That is, in the foreign matter inspection work on the wafer 1A after the film formation, the inspection work is performed with a sensitivity of detecting the foreign matter b having a size of 0.3 μm or more, for example. This detection sensitivity is a sensitivity for detecting a foreign substance b having a size that causes an obstacle to the process during the film forming process, and a foreign substance having a size within an allowable range does not interfere with the process, and is set so as not to be detected. It will be.

By the way, the foreign matter a which has adhered to the mirror-finished wafer 1 before the film formation processing step to be diagnosed is not the foreign matter adhered in the diagnostic film formation processing step, and therefore needs to be excluded from the diagnosis. In addition, an operation electron microscope (SE
M) and an X-ray analyzer (both not shown) require time and cost, etc., so that the analysis work for unimportant foreign substances interferes with the truly necessary foreign substance analysis work. Therefore, it is desirable to omit the analysis work for foreign matter that has adhered to the mirror-finished wafer 1 before the film forming process to be diagnosed.

Therefore, in the present embodiment, the CPU 20 causes the arithmetic unit 23 to execute the image processing as shown in FIG. 1 so that the deposition is performed in the film forming processing step shown in FIG. 1D. The distribution map 34 of the foreign matter d is calculated.

That is, the arithmetic unit 23 is a distribution map 3 of the foreign matter a before passing through the film forming process shown in FIG.
1 and the distribution diagram 32 of the foreign matter b after passing through the film forming process shown in FIG. 1B are superposed by image processing to obtain the superposition distribution diagram shown in FIG. 1C. Create 33.

When a target is attached to the wafer 1A before film formation during the superposing operation, the superposition can be very easily ensured with reference to the target.

If no target is attached,
For example, superposition is ensured by the following method. Of the foreign matter b group in the foreign matter distribution chart 32 after film formation,
For example, the foreign matters b scattered at three points are defined as temporary reference points. For these three points, the position of the foreign substance a in the foreign substance distribution map 31 before film formation can be obtained. At this time, when three points that completely overlap each other cannot be obtained, the approximate value thereof is obtained as a correction value, and the overlaying work is executed by the correction value.

As described above, the superposition distribution map 33
After the film is formed, the foreign matter a before film formation and the foreign matter b after film formation that overlap each other are erased by the image processing, so that the film formation processing shown in FIG. A distribution map of the adhering foreign matter d is obtained.

Here, the detection sensitivity in the foreign substance inspection work before passing the film forming process step and the detection sensitivity in the foreign substance inspection work after passing the film forming process step are the same, for example, 0.3 μm.
When the foreign matter inspection is performed with the detection sensitivity of m, as shown in FIG. 2, a distribution chart 41 of the foreign matter a before passing through the film forming process shown in FIG.
2 and the distribution diagram 42 of the foreign matter b after passing through the film forming process shown in FIG.
When the superposition diagram 43 shown in (c) is created, as is clear from FIG. 2 (c), the number of the foreign matter b after the film formation that does not overlap with the foreign matter a before the film formation is extremely large.

Then, as shown in FIG. 2D, the foreign matter a and the foreign matter b which are overlapped by the image processing are both erased, and all the remaining non-overlapping foreign matter b after the film formation are formed. Therefore, it is determined that the foreign matter d is attached. According to this determination, the extremely small foreign matter a attached to the mirror-finished wafer 1 is erroneously determined as the foreign matter d attached in the film forming process in the foreign substance inspection after the film forming process.

That is, the reason why the extremely small foreign matter a adhered to the mirror-finished wafer 1 is erroneously determined as the foreign matter d adhered in the film-formation processing in the foreign matter inspection on the wafer 1A after the film-formation processing is adhered to the mirror-finished wafer 1. And, moreover, the mirror surface wafer 1
In the film forming process, a very small foreign substance a that was not recognized as a foreign substance a that would be an obstacle during the foreign substance inspection
As shown in FIG. 2E, the film e is deposited on the foreign matter a to be in a bloated state, which causes an obstacle in the foreign matter inspection on the wafer 1A after the film forming process. This is because the foreign matter b is detected as

However, in the present embodiment, in the foreign matter inspection on the mirror-finished wafer 1 before the film formation, the foreign matter inspection is performed with high detection sensitivity (for example, 0.1 μm or more), while the film formation is performed. In the subsequent foreign matter inspection on the wafer 1A, the sensitivity lower than the detection sensitivity in the foreign matter inspection on the mirror-finished wafer 1 (for example, 0.3 μm or more)
Since the foreign matter inspection is performed with the above, it is possible to prevent the extremely small foreign matter a attached to the mirror-finished wafer 1 from being erroneously determined as the foreign matter d attached in the film forming process in the foreign matter inspection after the film forming process. You can

That is, in the foreign matter inspection of the mirror-finished wafer 1, since the foreign matter inspection is performed with high sensitivity such as 0.1 μm, even a minute foreign matter a of 0.1 μm is recognized. Become. Then, during the film forming process, some of the minute foreign matter a of 0.1 μm are enlarged to the size of the foreign matter b of 0.3 μm which is an obstacle due to the deposition of the film e.

When inspecting the foreign matter for the wafer 1A after film formation, a relatively low sensitivity, eg, 0.3 μm, is inspected. Therefore, 0.1 μm detected in the inspection before film formation processing is performed. The foreign substance a is not detected as a foreign substance that does not interfere. However, the foreign matter b having a size of 0.3 μm, which becomes large and becomes an obstacle during the film forming process, is also detected in the defect inspection after the film forming process.

As described above, in this embodiment, the foreign matter a of 0.1 μm adhered to the mirror-finished wafer 1 before the film forming process is enlarged to a size that causes an obstacle by the film forming process. Is detected as a foreign matter b of 0.3 μm which becomes an obstacle in the foreign matter inspection work on the wafer 1A after the film formation, and therefore, they overlap each other in the superposition step shown in FIG. 1C. As a result,
It is erased in the erasing step shown in (d). In other words, the foreign matter a that has adhered to the mirror-finished wafer 1 is not determined as the foreign matter b during the work of determining the foreign matter that adheres in the film forming process for the wafer 1A after film formation.

As a result, it is possible to prevent the minute foreign matter a formed on the mirror-finished wafer 1 before the film formation processing from being erroneously determined as the foreign matter d attached in the film formation processing in the foreign matter inspection after the film formation processing. can do. Therefore, since only the foreign matter d that has truly adhered in the film forming process can be specified, it is possible to properly execute the diagnosis or evaluation regarding the foreign substance generation in the film forming process.

According to the above described embodiment, the following effects can be obtained. (1) By subtracting the foreign substance distribution map 31 obtained by the foreign substance inspection work on the mirror-finished wafer 1 before film formation from the foreign substance distribution map 32 obtained by the foreign substance inspection work on the wafer 1A after film formation Since the data of the foreign matter d adhered in the film forming process can be automatically obtained, the tendency of the foreign substance d to adhere in the film forming process can be known accurately and quickly, and the diagnosis or evaluation of the film forming process can be performed. Can be made accurate and quick.

(2) Mirror-like wafer 1 before film formation
The foreign substance inspection is performed with a high detection sensitivity (for example, 0.1 μm or more) in the foreign substance inspection work for the wafer 1. On the other hand, the foreign substance inspection work for the wafer 1A after film formation is higher than the detection sensitivity in the foreign substance inspection for the mirror surface wafer 1. Since the foreign matter inspection is performed with low sensitivity (for example, 0.3 μm or more), the very small foreign matter a attached to the mirror-finished wafer 1 is attached to the foreign matter inspection after the film formation processing in the film formation processing. Since it is possible to prevent an erroneous determination as d, it is possible to prevent a decrease in diagnosis or evaluation of the film forming process.

(3) Since the foreign matter adhered before passing through the film forming process to be diagnosed by the above (1) and (2) can be excluded from the foreign substance data after passing through the film forming process, the foreign matter When the analytical inspection is performed on the composition, the inspection efficiency can be increased, and the accuracy of diagnosis or evaluation for the film forming process can be further increased.

Although the invention made by the present inventor has been specifically described based on the embodiments, the invention is not limited to the embodiments and various modifications can be made without departing from the scope of the invention. Needless to say.

For example, an image processing method is used as a method for comparing the foreign matter distribution before film formation with the foreign matter distribution after film formation and excluding the foreign matter distribution before film formation from the foreign matter distribution after film formation. Not limited to this, a method may be used in which the coordinates of the foreign matter distribution before film formation are compared with the coordinates of the foreign matter distribution after film formation to exclude foreign matter having the same coordinate value.

The defect for which data regarding the position of the defect is to be obtained is not limited to the foreign matter attached to the wafer, but may be a defect defect such as a defect defect, a protrusion defect, or a dimension error defect in the wafer visual inspection. .

The defect detecting means is not limited to the optical means configured to detect the scattered light by irradiating the wafer with a laser or the like, but the object to be inspected is charged with a charged particle beam such as an electron beam. May be used to detect the secondary particles or waves thereof.

In the above description, the case where the invention made by the present inventor is mainly applied to the foreign matter inspection technique for wafers which is the background field of application has been described, but the present invention is not limited to this, and a reticle or a liquid crystal is used. panel,
Further, it can be applied to general defect inspection devices for printed wiring boards and the like. In particular, the present invention can be applied to all defect inspection techniques for a plate-like object to which a film forming process is applied, and can obtain excellent effects.

[0063]

The effects obtained by the typical ones of the inventions disclosed in the present application will be briefly described as follows.

In the defect inspection work on the semiconductor wafer before the film formation is performed, the defect inspection is performed with high detection sensitivity. On the other hand, the defect inspection work on the semiconductor wafer after the film formation is performed in the defect inspection on the semiconductor wafer. By performing the defect inspection with a sensitivity lower than the detection sensitivity, the microscopic defects that had adhered to the semiconductor wafer before the film formation process became defects that were adhered during the film formation process during the defect inspection after the film formation process. Since it is possible to prevent erroneous determination, it is possible to prevent deterioration of diagnosis or evaluation of the film forming process.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining a method for inspecting foreign matter on a wafer, which is an embodiment of the present invention.

FIG. 2 is an explanatory view showing a comparative example for explaining the foreign matter inspection method for the wafer.

FIG. 3 is a schematic view showing a wafer foreign matter inspection apparatus which is an embodiment of the present invention and used in the wafer foreign matter inspection method.

[Explanation of symbols]

1 ... Mirror surface wafer (semiconductor wafer before film formation processing), 1A ...
Wafer after film formation (semiconductor wafer after film formation processing), 2 ... inspection chamber, 3 ... gate, 4 ... loading / unloading stage, 5 ... foreign matter inspection stage, 6 ... holder, 7 ...
Moving table, 8 ... Linear encoder, 9 ... Feed screw device, 1
0 ... Motor, 11 ... Holder controller, 12 ... Laser oscillator, 13 ... Scanning mirror, 14 ... Laser, 15 ...
Scattered light, 16A, 16B ... Photo sensor, 17 ... Foreign matter detection controller, 18 ... Position detector, 19 ... Position detection controller, 20 ... CPU, 21 ... Console, 22 ... Memory (defect data storage section), 23 ... Computing section, 24 ... Output device, 31, 41 ... Distribution map of foreign matter before passing through film forming process, 32, 42 ... Distribution map of foreign material after passing through film forming process, 3
3, 43 ... Overlay distribution chart, 34, 44 ... Foreign matter distribution chart determined to be foreign matter adhered in the film formation processing step, a ... Foreign matter detected in inspection before film formation processing, b ... After film formation processing Foreign matter detected by the inspection of d, foreign matter determined to be attached in the film forming process, e.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yuji Kato 5-20-1 Kamimizuhoncho, Kodaira-shi, Tokyo Inside the Semiconductor Division, Hitachi, Ltd. (72) Inventor Masahiro Fujita 5 Kamimizumoto-cho, Kodaira-shi, Tokyo No. 20-1 Stock Company Hitachi Ltd. Semiconductor Division

Claims (4)

[Claims] 1. A defect inspection method for performing an appearance defect inspection on a semiconductor wafer that has been subjected to a film forming process, wherein the appearance defect inspection is performed on the semiconductor wafer with high sensitivity before the film forming process is performed. A step of storing the position of the defect as an inspection result, and, after the film forming process is performed on this semiconductor wafer,
The step of performing the visual defect inspection on the semiconductor wafer after the film forming process with a lower sensitivity than the sensitivity before the film forming process, the position of the defect as the result of the visual inspection after the film forming process, and the film forming process. By comparing with the position of the defect which is the appearance inspection result before the processing, and by subtracting the defect distribution which is the appearance inspection result before the film forming processing from the defect distribution which is the appearance inspection result after the film forming processing, A defect inspection method comprising: a step of identifying defects formed by film processing. 2. The collation work between the position of the defect, which is the appearance inspection result after the film forming process, and the position of the defect, which is the appearance inspection result before the film forming process, is performed by the image superposition process, The work of subtracting the defect distribution that is the appearance inspection result before the film formation processing from the defect distribution that is the appearance inspection result after the film processing is performed by erasing the images of the overlapping defects. The defect inspection method according to claim 1. 3. The collation work between the position of the defect, which is the appearance inspection result after the film forming process, and the position of the defect, which is the appearance inspection result before the film forming process, is performed by collating the coordinate positions. The operation of subtracting the defect distribution, which is the appearance inspection result before the film formation processing, from the defect distribution, which is the appearance inspection result after the film processing, is performed by erasing defects having the same coordinate value. The defect inspection method according to claim 1, which is characterized in that. 4. An irradiation device for irradiating a semiconductor wafer with an inspection wave or an inspection particle beam, a detection device for detecting scattered waves or particles of the inspection wave or inspection particle beam with which the semiconductor wafer is irradiated on the semiconductor wafer, and a detection device. In a defect inspection apparatus that includes a recognition device that recognizes the position of a defect based on the detection of the defect, and performs an appearance defect inspection on a semiconductor wafer on which a film formation process is performed, the film formation process is performed on the semiconductor wafer. A storage unit for storing the position of a defect as an inspection result of the appearance defect inspection performed with high sensitivity before, and after the film forming process is performed on this semiconductor wafer,
Storage means for storing the position of a defect as an inspection result of the appearance defect inspection performed on the semiconductor wafer after the film forming process with a sensitivity lower than that before the film forming process, and the appearance after the film forming process. The position of the defect which is the inspection result and the position of the defect which is the appearance inspection result before the film forming process are collated, and the appearance inspection before the film forming process is performed based on the defect distribution which is the appearance inspection result after the film forming process. A defect inspection apparatus, comprising: an arithmetic processing unit that identifies defects formed by a film forming process by subtracting the resulting defect distribution.