JP2003174065A - System, method and program for inspecting semiconductor substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform noncontact and nondestructive pattern inspection of a semiconductor substrate subjected to CMP stably. <P>SOLUTION: The system 1 for inspecting the pattern of a semiconductor substrate 9 comprises an optical head section 11 for acquiring the two-dimensional image of the pattern of the semiconductor substrate 9, and a computer 13 performing processing. The computer 13 is provided previously with a reference image and its edge image and pattern matching is performed between an acquired image and the reference image in order to determine a difference image. In the difference image, mean absolute pixel value is compared with a specified threshold value while excluding an edge region represented by the edge image thus detecting presence of a metal residual film. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for inspecting a pattern on a semiconductor substrate.

[0002]

2. Description of the Related Art A semiconductor substrate (hereinafter referred to as "substrate").
In recent years, in the circuit forming process, the use of the damascene process is becoming mainstream. In the damascene process, first, as shown in FIG. 1, a wiring groove 911 is formed in a silicon oxide (SiO ₂ , hereinafter referred to as “oxide film”) 91 which is an insulator, and the wiring groove 911 is formed in the groove 911. The metal of is embedded.
As the metal for wiring, a wiring metal 92 for forming wiring is used.
And a barrier metal 93 for preventing the ions of the wiring metal from diffusing into the oxide film.

After the metal has been embedded in the groove 911, as shown in FIG.
As shown in (4), excess metal that crosses the wiring path is removed, and proper wiring is formed. Chemical mechanical polishing (Chemic polishing) is often used to remove excess metal.
Hal Mechanical Polishing, hereinafter abbreviated as “CMP”. ) Is used. CMP removes excess metal and provides the substrate surface flatness required for subsequent photolithography steps.

In the circuit forming process using the damascene process, it is necessary to detect whether removal of excess metal is completed (end point detection in polishing). Conventionally, as an end point detection method, a polishing end scheduled time is obtained from the amount of grinding per unit time, and it is considered that polishing is completed at the polishing end scheduled time, or a polishing end point is determined by a change in the rotation torque of the polishing table. A method of detecting is used.

However, it is impossible to confirm whether or not a metal is left in a fine area on the substrate to cause a short circuit in the circuit by the method of determining the end point by the change of the scheduled polishing end time or the rotation torque. Therefore, at present, the substrate after polishing is appropriately taken out, and an inspector inspects with a microscope whether or not there is a metal residue (hereinafter referred to as “metal residual film”). , "Chip"), the presence or absence of a short circuit is inspected using a tester.

[0006]

When inspecting a residual metal film by an inspector using a microscope, the inspector needs to observe a fine pattern for a long time.
Naturally, the degree of fatigue of the person in charge increases. As a result, variations in inspection quality may occur.

Further, the test using the tester is a test carried out after the chip is cut out from the substrate, and since the test result is obtained after a considerable time has passed from the polishing process, the test result cannot be used efficiently. .

The present invention has been made in view of the above problems, and it is an object of the present invention to perform a non-contact, non-destructive and stable inspection of a substrate pattern before cutting the substrate to produce chips.

[0009]

According to a first aspect of the present invention, there is provided a semiconductor substrate inspection apparatus for inspecting a pattern on a semiconductor substrate, the illumination unit irradiating the semiconductor substrate with illumination light, and the semiconductor substrate. An arithmetic unit that acquires data of a two-dimensional image of a pattern, an arithmetic unit that performs arithmetic processing on the data of the two-dimensional image, and a storage unit that stores data of a reference image, the arithmetic unit including: The pixels of the reference image and the pixels of the two-dimensional image are associated with each other, and the difference image data is generated by obtaining the difference between the values of the corresponding pixels of the reference image and the two-dimensional image.

The invention according to claim 2 is the semiconductor substrate inspection apparatus according to claim 1, further comprising a display section for displaying the difference image.

According to a third aspect of the present invention, in the semiconductor substrate inspection apparatus according to the first or second aspect, the arithmetic unit resembles the reference image and the two-dimensional image based on the difference image. The index value indicating the degree of is obtained, and the inspection result is acquired by comparing the index value with a predetermined threshold value.

According to a fourth aspect of the present invention, in the semiconductor substrate inspection apparatus according to the third aspect, the storage section stores data of an edge image obtained by extracting an edge from the reference image. When the index value is obtained, the pixels corresponding to the edge area indicated by the edge image in the difference image are substantially excluded.

A fifth aspect of the present invention is the semiconductor substrate inspection apparatus according to any one of the first to fourth aspects, in which the illumination section emits monochromatic light as the illumination light.

A sixth aspect of the present invention is the semiconductor substrate inspection apparatus according to any one of the first to fifth aspects, wherein the illumination section selects any one of a plurality of types of illumination light. Irradiate the semiconductor substrate.

According to a seventh aspect of the present invention, in the semiconductor substrate inspection apparatus according to any of the first to sixth aspects, the arithmetic unit associates the pixels of the reference image with the pixels of the two-dimensional image. When attaching, the 2
The two-dimensional image is correlated with the reference image by rotating the two-dimensional image at substantially any angle.

An eighth aspect of the present invention is the semiconductor substrate inspection apparatus according to any one of the first to seventh aspects, wherein the reference image is an image of a semiconductor substrate subjected to appropriate chemical mechanical polishing. Is.

According to a ninth aspect of the present invention, there is provided a semiconductor substrate inspection method for inspecting a pattern on a semiconductor substrate, comprising a step of irradiating the semiconductor substrate with illumination light, and data of a two-dimensional image of the pattern on the semiconductor substrate. Of the reference image and the pixel of the two-dimensional image prepared in advance, the difference between the values of the corresponding pixels of the reference image and the two-dimensional image A step of generating difference image data by obtaining the difference image, and a step of generating the difference between the reference image and the two-dimensional image based on the difference image while substantially excluding pixels corresponding to the edge region indicated by the edge image prepared in advance. And a step of obtaining an inspection result by obtaining an index value indicating a degree of similarity and comparing the index value with a predetermined threshold value.

According to a tenth aspect of the present invention, there is provided a program for causing a computer to execute inspection of a semiconductor substrate,
Execution of the program by the computer includes causing the computer to associate pixels of a reference image prepared in advance with pixels of a two-dimensional image obtained by imaging a semiconductor substrate, and the reference image. A step of generating difference image data by obtaining a difference between pixel values corresponding to the two-dimensional image, and substantially excluding pixels corresponding to an edge region indicated by a previously prepared edge image. Based on the difference image, the reference image and the 2
The step of obtaining an inspection result by obtaining an index value indicating the degree of similarity to the three-dimensional image and comparing the index value with a predetermined threshold value is executed.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 is a diagram showing an overall configuration of a semiconductor substrate inspection apparatus (hereinafter referred to as “inspection apparatus”) 1 for inspecting a semiconductor substrate 9 having a wiring pattern formed by a damascene process. .

The inspection apparatus 1 includes an optical head unit 11 that captures two-dimensional image data by capturing an image of the substrate 9, and a stage that supports the substrate 9 and moves the substrate 9 relative to the optical head unit 11. Section 12, and computer 1 connected to optical head section 11 and stage section 12
Have three.

The optical head unit 11 guides the illumination light to the substrate 9 and an optical system 111 on which the light from the substrate 9 is incident, and an image pickup device for converting the image of the substrate 9 formed by the optical system 111 into an electrical signal. Light source unit 2 that irradiates the substrate 9 with the illumination light by selecting any one of the illumination light 112 and the plurality of types of illumination light and emitting the light to the optical system 111.
Have.

The light source unit 2 has a plurality of light sources 21 according to the type of illumination light, and the light source driving section 22 has a plurality of light sources 2.
By moving 1 the illumination light is switched. As the light source 21, although a plurality of light sources that emit illumination light according to the characteristics of the surface of the substrate 9 are prepared, a light source that emits at least monochromatic light in order to improve the visibility of the multilayer film is included. Of course, the plurality of light sources 21 may include those that emit white light or light of a bulb color.

The stage section 12 has a stage 121 for supporting the substrate 9 and a stage drive section 122 for moving the stage 121 in a horizontal plane. A mechanism for rotating the stage 121 in a horizontal plane may be added to the stage driving unit 122.

The computer 13, as shown in FIG.
It has a general computer system configuration in which a CPU 31 for performing various arithmetic processes, a ROM 32 for storing a basic program, and a RAM 33 for storing various information are connected to a bus line. The bus line further includes a fixed disk 34 for storing information, a display 35 for displaying various information, and a keyboard 3 for receiving input from an operator.
6a and mouse 36b, optical disk, magnetic disk,
A reading device 37 for reading information from a computer-readable recording medium 8 such as a magneto-optical disk, and
The communication unit 38 that communicates with the imaging device 112, the light source unit 2, and the stage driving unit 122 is appropriately connected via an interface (I / F) or the like.

The computer 13 has a reading device 3 in advance.
The program 341 is read from the recording medium 8 via the storage medium 7 and stored in the fixed disk 34. Then, the program 341 is copied to the RAM 33 and the CPU 3
When the computer 1 executes the arithmetic processing according to the program in the RAM 33 (that is, the computer executes the program), the computer 13 controls various components and executes the inspection.

In FIG. 5, when the CPU 31 operates according to the program 341, the CPU 31, the ROM 32,
It is a block diagram which shows the function structure implement | achieved by RAM33 etc. In FIG. 5, the control unit 41, the matching unit 42, the difference image generation unit 43, and the determination unit 44 show the functions realized by the CPU 31 and the like. Note that these functions may be realized by a dedicated electric circuit, or an electric circuit may be partially used.

The control section 41 receives an image signal from the image pickup device 112, stores it in the fixed disk 34 as acquired image data 342, and controls the operations of the light source unit 2 and the stage drive section 122. The matching unit 42
An image acquired by the imaging device 112 (hereinafter, referred to as “acquired image”) is pattern-matched with a reference image described later, the difference image generation unit 43 obtains a difference image between the acquired image and the reference image, and the determination unit. Reference numeral 44 determines whether or not there is a residual metal film on the substrate 9.

In the inspection device 1, a preparatory operation for the inspection is performed before the inspection operation is performed. FIG. 6 is a diagram showing a flow of an operation of registering a recipe which is a set of various data used for inspection as a preparatory operation.

In registering a recipe, first, an appropriate CM is prepared in advance.
The reference substrate subjected to P is loaded on the stage unit 12 (step S11). Next, the illumination light is selected according to the film type of the inspection location (step S12). That is, the operator operates the keyboard 36a and the mouse 36b of the computer 3.
The illumination light is selected by operating, and the control unit 41 drives the light source driving unit 22 of the light source unit 2 and turns on the selected light source 21 according to the operation.

The illumination light is selected so that an image with high contrast can be obtained based on the characteristics of the metal or thin film to be detected as a defect, and monochromatic light is preferably selected. This makes it possible to obtain an image with a high S / N ratio according to the characteristics of the inspection location.

Then, the stage 121 is moved based on the operation of the operator, and the inspection point in the specific chip on the reference substrate is moved to just below the optical head unit 11 (step S).
13). After that, the image pickup device 112 picks up an image, and the data of the reference image showing the reference pattern is stored in the fixed disk 34 as the reference image data 303 (see FIG. 5) (step S14).

FIG. 7 is a diagram illustrating a plurality of inspection points 941 in a region corresponding to one chip 94 on the substrate 9, and FIG. 8 shows one of the chips 94 on the substrate 9 to be inspected (parallel. It is a figure which illustrates the position of what is attached with a diagonal line. As shown in FIG. 7, one chip 9 is used for one imaging.
Only a limited area within 4 is imaged. In one chip 94, a place where a residual metal film is likely to exist is previously known based on the state of the lower layer and the state of the wiring pattern, and such a place is determined as an inspection place 941. .

Further, as shown in FIG. 8, it has been empirically found that the position of the chip 94 on which a metal residual film is likely to exist is also found on the one substrate 9 from the characteristics of CMP. Therefore, in the inspection operation described later, the inspection locations 941 of all the chips 94 to be inspected are inspected. When registering a recipe, various conditions are acquired for only one chip 94. Then, the recipe is applied to each chip 94 in the inspection described later.

When the acquisition of the reference image data 303 is completed, the operator sets a threshold value for judging the quality of the pattern on the substrate 9 (step S15). The threshold value may be set based on the experience of the operator, or may be performed using a separately prepared defective substrate.

Although illustration of the operation when a defective substrate is used is omitted, first, a defective substrate inspection point 9 is used.
The image data of 41 is acquired, and the difference image between the reference image and the image of the defective substrate is obtained. Then, a value is obtained by the same method as an index value (a value that is compared with a threshold value, which will be described later, refer to the inspection operation for details), and the operator sets the threshold value based on the obtained value. To set.

Next, an edge image is generated by extracting the edge of the reference image as a line having a constant width (step S1).
6). For example, when the reference image is the one shown in FIG. 9, the edge image shown in FIG. 10 is generated and stored in the fixed disk 34 as the edge image data 304 (see FIG. 5). In addition, when the edge image is generated, the peripheral portion of the image is also regarded as an edge.

In the edge image generation, first, an operator to be superimposed on the reference image is prepared. FIG. 11 is a diagram illustrating an operator, and the operator has a size in which an odd number of pixels are arranged vertically and horizontally. Then, when the absolute value of the difference between the value of the central pixel of the operator (pixels with parallel hatching in FIG. 11) superimposed on the reference image and the values of other pixels is added, and the added value exceeds a predetermined value. The value of the corresponding pixel of the edge image is set to 1, and the pixel value is set to 0 when the value is equal to or less than a predetermined value. Since edge detection by this method does not have directivity, it can be performed more easily than edge detection for each direction which is usually performed.

Of course, operators of multiple sizes may be applied to one reference image, in which case the above-mentioned sum is divided by the number of pixels of the operator in order to remove the influence of the operator's size. Applying operators of multiple sizes to the reference image produces an edge image that can make appropriate decisions for various patterns during inspection.

Step S for one inspection point 941
When 12 to S16 are completed, steps S12 to S16 are repeated for the next inspection location 941 in the same chip 94 (step S17). When steps S12 to S16 are executed for all the inspection points 941 in one chip 94, the chips to be inspected on the substrate 9 (hereinafter,
It is called "target chip". ) 94 is selected (step S18). For example, the chip 94 with parallel hatching in FIG. 8 is selected as the target chip.

Thereafter, the information related to the above operation is registered as the recipe 343 in the fixed disk 34 as shown in FIG. 5 (that is, stored in the data structure shown in the recipe 343) (step S19). The illumination data 301 shown in FIG. 5 indicates the type of illumination light selected in step S12 for each inspection location 941, and the position data 302 is the inspection location 941 specified in step S13.
The reference image data 303 is the image data of each inspection location 941 acquired in step S14, and the edge image data 304 is the image data of each inspection location 941 generated in step S16. , The threshold value 305 is set in step S15 for each inspection point 941.
Indicates the value set in.

Finally, the reference substrate is unloaded from the stage 121, and the recipe registration operation is completed (step S20).

FIGS. 12 and 13 are diagrams showing the flow of the operation of the inspection apparatus 1 when an inspection is performed on one substrate (hereinafter referred to as “target substrate”) 9. Hereinafter, the inspection operation will be described with reference to FIGS. 3 to 5 and with reference to FIGS. 12 and 13.

First, the target substrate 9 is loaded on the stage 121 of the stage section 12 (step S31). The target substrate 9 may be automatically loaded from a CMP apparatus or a facility line having a CMP apparatus, and an operator may place the substrate 9 on the stage 121 as appropriate.

In the inspection device 1, the loaded target substrate 9
The computer 13 confirms whether or not is the same type as the substrate 9 of the previous inspection (step S32), and if it is not the same type of substrate, the recipe 343 corresponding to the type of the target substrate 9 is loaded (step S33). . That is, the recipe 343 is read from the fixed disk 34, stored in the RAM 33, and the recipe 343 can be referred to by the CPU 31. The loading of the recipe may be an operation of only specifying one recipe 343 in the fixed disk 34.
Further, in FIG. 5, for the sake of convenience, the recipe 3 in the fixed disk 34 is shown.
43 shows the flow of various data.

Next, the image pickup device 112 picks up an image at a low magnification under the control of the controller 41, and the CPU 31 compares the obtained image with a previously prepared pattern (notch shape or characteristic pattern). The approximate position and orientation of the target substrate 9 on the stage 121 are detected.
As pre-alignment, the control unit 41 controls the stage drive unit 122 so that the first chip 94 to be inspected on the target substrate 9 is located approximately below the optical head unit 11 based on the detection result (step S34).

When the pre-alignment is completed, the control unit 4
1 controls the light source drive unit 22 with reference to the illumination data 301 of the recipe 343, positions the light source 21 that emits illumination light suitable for the inspection location 941 at the light introduction position to the optical system 111, and selects the selected light source. 21 is turned on. As a result, the selected illumination light is applied to the target substrate 9 via the optical system 111 (step S35).

Further, the control unit 41 moves the stage 121 with reference to the position data 302 of the recipe 343 so that the first inspection point 941 of the target chip 94 to be inspected first is located directly below the optical head unit 11. (Step S36). The imaging device 112 is the optical system 1.
The image of the inspection location 941 is acquired as a signal via 11, and the image signal is converted into digital data by the circuit in the imaging device 112 or the control unit 41, and is stored in the fixed disk 34 as acquired image data 342 (step S37). ). FIG. 14 is a diagram illustrating an acquired image acquired corresponding to the reference image shown in FIG. 9.

The acquired image data 342 and the reference image data 303 are sent to the matching unit 42, and the positional relationship between the acquired image and the reference image is examined in more detail by using pattern matching by the normalized correlation method, for example ( Step S38). Specifically, the acquired image is superimposed on the reference image at various positions and orientations, and a vector having all pixel values of overlapping regions in each image as elements is obtained. Two vectors corresponding to both images are obtained. The inner product of is calculated. Then, the position and orientation of the acquired image when the inner product becomes the largest are obtained.

In the pattern matching, the correlation (inner product) between the reference image and the acquired image is obtained while rotating the acquired image with respect to the reference image at substantially any angle. As a result, the correspondence relationship between both images is obtained regardless of the orientation of the substrate 9. For example, when the substrate 9 is automatically loaded from an apparatus for processing while rotating the substrate 9 such as a CMP apparatus, the substrate 9 immediately after loading is oriented in an arbitrary direction. Even in such a case, the inspection apparatus 1 can perform pattern matching without rotating the stage 121.

By pattern matching, as shown in FIG. 15, the reference image 951 can be associated with the acquired image 952 by translating the reference image 951 by the movement vector v and rotating it by an angle θ around a predetermined origin. When it is found that the reference image 951 and the acquired image 952 are overlapped with each other (a region hatched with parallel lines in FIG. 15).
, The position vector p of one pixel in the coordinate system of the acquired image 952 is calculated by the equation 1 in the reference image 9
It becomes possible to convert into the position vector q of the corresponding pixel in the coordinate system of 51. However, in Equation 1, A (-
θ) is a matrix that rotates the position vector by an angle (−θ).

[0051]

[Equation 1]

In the acquired image 952, a value such as a negative pixel value indicating the non-operation target is set to the pixel in which the pixel corresponding to the reference image 951 does not exist. As a result, the inspection location 941 that is actually the calculation target in the acquired image 952
Area (hereinafter, referred to as "inspection area") is specified (step S39).

Acquired image data 342, reference image data 3
03, the movement vector v for superimposing both images, the rotation angle θ, and the inspection region are input to the difference image generation unit 43, and have a difference between the values of corresponding pixels of both images as a pixel value with respect to the overlapping portion of both images. Data of the difference image is generated (step S40). FIG. 16 is a diagram exemplifying a difference image obtained from the reference image shown in FIG. 9 and the acquired image shown in FIG.

The difference image data and the edge image data 304 in the recipe 343 are sent to the judging section 44, and the difference image is masked by the edge image (step S4).
1). For example, the value of the pixel of the difference image corresponding to the pixel of which the value is 1 in the edge image (that is, the pixel of the edge area) is a special value excluded from the calculation of the determination. Then, the average value of the absolute values of the pixels other than the pixels to be excluded in the difference image is obtained, and the average value is compared with the threshold value 305 in the recipe 343.

When the average value is equal to or higher than the threshold value 305, it is determined that there is a residual metal film, and the average value is equal to the threshold value 30.
If it is less than 5, it is determined that there is no residual metal film (step S51). As described above, in the inspection device 1, the average value is used as the index value indicating the degree of similarity between the reference image and the acquired image.

Usually, the matching between the reference image and the acquired image involves an error of at least 1 pixel or less. That is, the value of the pixel corresponding to the edge changes depending on where the edge of the pattern is located with respect to one pixel. Also, an error occurs when quantizing the pixel value. Therefore, when the difference image is obtained after the pattern matching, the absolute value of the pixel value corresponding to the edge of the pattern becomes large. Therefore, the determination unit 44 enhances the inspection accuracy by using the edge image to make a determination by substantially excluding the pixels corresponding to the edge.

When the inspection of one inspection place 941 is completed, it is confirmed whether or not there is an uninspected next inspection place 941 in the target chip 94 (step S52). If the uninspected inspection place 941 exists, the step is performed. S35
~ S41 and step S51 are repeated. Furthermore, when the inspection of all the inspection points 941 of one target chip 94 is completed, it is confirmed whether or not there is an uninspected next target chip 94 (step S53). If there is an uninspected target chip 94, Then, steps S35 to S41 and step S51 are repeated for each inspection location 941 of the new target chip 94.

All inspection points 9 of all target chips 94
When the inspection of 41 is completed, a list of inspection results is displayed on the display 35 (step S54). The person in charge of the inspection apparatus 1 is allowed to select the inspection point 941 where the inspection result in which the metal residual film exists by using the keyboard 36a and the mouse 36b, and the operator can check the inspection point 91.
By selecting 41, the difference image (or acquired image) corresponding to the inspection result is displayed on the display 35 (steps S55 and S56). This allows the operator to accurately grasp the state of the residual metal film as a two-dimensional distribution.

When the operator grasps the inspection result, the target substrate 9 is unloaded from the stage 121 (step S57). In addition, by automatically loading and unloading the target substrate 9 from the substrate processing line,
The inspection device 1 can be in-line. The inspection result is the chip 9 obtained from the unloaded target substrate 9.
4 is processed or sent to another device for inspecting the good or bad of the chip 94 for use. This improves the efficiency of processing and inspection in other devices.

Depending on the inspection result, CMP may be performed again on the target substrate 9. As a result, the yield of the chips 94 from the target substrate 9 on which insufficient CMP has been performed can be improved.

As described above, in the inspection apparatus 1, the pattern inspection of the substrate 9 can be automatically performed and the defective portion can be accurately grasped as a two-dimensional image, so that the burden on the inspection person is reduced. Moreover, the inspection of the pattern of the semiconductor substrate can be stably performed in a non-contact and non-destructive manner.

The present invention is not limited to the above embodiment, and various modifications can be made.

For example, in the above embodiment, the inspection of the target substrate 9 is automatically performed based on the difference image, but the difference image may only be displayed. Even when the suitability of the pattern is judged by visual inspection of the difference image, the burden on the person in charge can be significantly reduced as compared with the conventional case where the person in charge inspects using a microscope.

The pixel value of the difference image may be the absolute value of the difference in pixel value between the reference image and the acquired image. Further, the method for obtaining the inspection result from the difference image is not limited to the above method, and may be appropriately changed.

Further, the difference between the pixel values of the reference image and the acquired image binarized by a predetermined threshold value may be used as a difference image for display or determination. Noise may be removed by subjecting the binarized image to contraction / expansion processing. Also, 2
The digitization may be selectively performed by the operation of the person in charge.

The difference image does not have to exist as difference image data, and the value corresponding to the pixel value of the difference image may be simply obtained in the process of calculation. That is, an appropriate inspection is realized by substantially performing the inspection based on the pixel value of the difference image.

The edge image may be any image as long as it is an image showing a portion substantially corresponding to an edge.
For example, an image subjected to expansion processing after normal edge extraction may be used as the edge image.

In the above embodiment, the pixels of the difference image corresponding to the edge area of the edge image are excluded from the calculation target in the inspection. However, if they are substantially excluded from the calculation target, the mask by the edge image is not included. It may be realized by other methods. For example, the pixel value of the difference image corresponding to the edge area may be simply set to 0.

In the above embodiment, the stage 121 may move or rotate after the pattern matching. This enables more accurate inspection. It is sufficient that the optical head unit 11 and the stage 121 are movable relative to each other.
21 may be movable.

In the above embodiment, the illumination light is selected for each inspection location 941, but the type of illumination light may be fixed for one substrate 9.

The inspection performed by the inspection apparatus 1 is not limited to the CMP residual film inspection, but can be widely used for the defect inspection of the pattern of the semiconductor substrate.

[0072]

According to the first to tenth aspects of the present invention, it is possible to stably inspect the pattern of the semiconductor substrate in a non-contact and non-destructive manner.

Further, in the invention of claim 2, the defective portion can be accurately grasped.

According to the third aspect of the invention, the inspection can be automatically performed.

According to the invention of claim 4, the inspection accuracy can be improved.

According to the fifth and sixth aspects of the invention, it is possible to obtain a two-dimensional image with high contrast according to the characteristics of the semiconductor substrate.

According to the invention of claim 7, the inspection can be performed regardless of the orientation of the semiconductor substrate.

According to the eighth aspect of the invention, it is possible to properly inspect the residual metal film.

[Brief description of drawings]

FIG. 1 is a diagram for explaining how a wiring pattern is formed on a substrate.

FIG. 2 is a diagram for explaining how a wiring pattern is formed on a substrate.

FIG. 3 is a diagram showing an overall configuration of an inspection device.

FIG. 4 is a diagram showing a configuration of a computer.

FIG. 5 is a block diagram showing a functional configuration of a computer.

FIG. 6 is a diagram showing a flow of a recipe registration operation.

FIG. 7 is a diagram illustrating a plurality of inspection points.

FIG. 8 is a diagram exemplifying positions of chips to be inspected on a substrate.

FIG. 9 is a diagram illustrating a reference image.

FIG. 10 is a diagram illustrating an edge image.

FIG. 11 is a diagram illustrating an operator.

FIG. 12 is a diagram showing a flow of an inspection operation.

FIG. 13 is a diagram showing a flow of an inspection operation.

FIG. 14 is a diagram illustrating an acquired image.

FIG. 15 is a diagram illustrating an example of superimposing a reference image and an acquired image.

FIG. 16 is a diagram illustrating a difference image.

[Explanation of symbols]

1 Inspection Device 2 Light Source Unit 9 Board 13 Computer 21 Light Source 31 CPU 34 Fixed Disk 35 Display 42 Matching Section 43 Difference Image Generation Section 44 Judgment Section 112 Imaging Device 303 Reference Image Data 304 Edge Image Data 305 Threshold 341 Program 342 Acquisition Image Data 951 Reference image 952 Acquisition image S35, S37, S38, S40, S41, S51 Step

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Claims (10)

[Claims] 1. A semiconductor substrate inspecting apparatus for inspecting a pattern on a semiconductor substrate, comprising: an illuminating unit for irradiating the semiconductor substrate with illumination light; and an imaging unit for acquiring data of a two-dimensional image of the pattern on the semiconductor substrate. A calculation unit that performs calculation processing on the data of the two-dimensional image; and a storage unit that stores data of the reference image, the calculation unit including pixels of the reference image and pixels of the two-dimensional image. Is performed, and the difference image data is generated by obtaining the difference between the values of the corresponding pixels in the reference image and the two-dimensional image, and the semiconductor substrate inspection apparatus is generated. 2. The semiconductor substrate inspection apparatus according to claim 1, further comprising a display unit that displays the difference image. 3. The semiconductor substrate inspecting apparatus according to claim 1, wherein the arithmetic unit produces an index value indicating a degree of similarity between the reference image and the two-dimensional image based on the difference image. A semiconductor substrate inspection apparatus, wherein the inspection result is obtained by obtaining and comparing the index value with a predetermined threshold value. 4. The semiconductor substrate inspection apparatus according to claim 3, wherein the storage unit stores edge image data obtained by extracting edges from the reference image, and when the index value is obtained. The semiconductor substrate inspection apparatus is characterized in that pixels corresponding to an edge region indicated by the edge image are substantially excluded from the difference image. 5. The semiconductor substrate inspection apparatus according to claim 1, wherein the illumination unit emits monochromatic light as the illumination light. 6. The semiconductor substrate inspection apparatus according to claim 1, wherein the illumination section selects any one of a plurality of types of illumination light and irradiates the semiconductor substrate. Characteristic semiconductor substrate inspection device. 7. The semiconductor substrate inspection apparatus according to claim 1, wherein the arithmetic unit associates the pixels of the reference image with the pixels of the two-dimensional image. An apparatus for inspecting a semiconductor substrate, characterized in that the correlation between the reference image and the two-dimensional image is obtained by rotating the two-dimensional image with respect to the reference image at a substantially arbitrary angle. 8. The semiconductor substrate inspection apparatus according to claim 1, wherein the reference image is an image of a semiconductor substrate subjected to appropriate chemical mechanical polishing. Semiconductor substrate inspection equipment. 9. A semiconductor substrate inspection method for inspecting a pattern on a semiconductor substrate, comprising: illuminating the semiconductor substrate with illumination light; and obtaining data of a two-dimensional image of the pattern on the semiconductor substrate in advance. Data of the difference image by associating the prepared pixels of the reference image with the pixels of the two-dimensional image, and obtaining the difference between the values of the corresponding pixels of the reference image and the two-dimensional image. And a parameter value indicating a degree of similarity between the reference image and the two-dimensional image based on the difference image while substantially excluding pixels corresponding to the edge region indicated by the edge image prepared in advance. And a step of obtaining an inspection result by comparing the index value with a predetermined threshold value. 10. A program for causing a computer to execute an inspection of a semiconductor substrate, wherein the execution of the program by the computer is obtained by imaging a pixel of a reference image prepared in advance and the semiconductor substrate by the computer. A step of associating with a pixel of the two-dimensional image, a step of generating difference image data by obtaining a difference between values of corresponding pixels of the reference image and the two-dimensional image, An index value indicating the degree of similarity between the reference image and the two-dimensional image is obtained based on the difference image while substantially excluding pixels corresponding to the edge region indicated by the generated edge image, and the index value and the predetermined value are determined. And a step of acquiring an inspection result by comparing the threshold value of the program with the threshold value of.