TWI827863B - Wafer appearance inspection device and method - Google Patents

Abstract

An object of the present invention is to provide an inspection device and method that can automatically inspect relatively large-sized damage, contamination, and adhesion of foreign matter that are within the scope of macroscopic inspection based on an enlarged image of a small area obtained for microscopic inspection. wait. The wafer appearance inspection device and method of the present invention captures an appearance image of a wafer having a repeating pattern, and performs inspection by comparing the captured image with a pre-registered reference image, and The repeating pattern formed on the wafer to be inspected is divided and photographed while gradually changing the imaging location. The divided and photographed images are combined to generate a large-sized inspection image for macro inspection. The large-sized inspection image is then The inspection image for macro inspection is compressed to generate a small size inspection image for macro inspection; and The small-sized macro-inspection inspection image is compared with a pre-generated and registered small-sized macro-inspection reference image, and the inspection target wafer is macro-inspected.

Description

Wafer appearance inspection device and method

The present invention relates to a method for photographing a repeating appearance pattern of a device chip or the like formed on a wafer or an appearance image of a non-patterned area set on a wafer to be inspected, and comparing the captured inspection image with a pre-registered reference image. A wafer appearance inspection device and method for comparing and inspecting the device wafer, etc.

When a semiconductor device is formed with a plurality of semiconductor device circuits (i.e., a repeating appearance pattern of the device wafer) on a semiconductor wafer, it is then diced into individual chip parts. The chip parts are packaged and produced as individual electronic parts. goods or assemblies into electrical products.

Furthermore, the inspection image of the repetitive appearance pattern of the device chip formed on the wafer before each wafer component is singulated is compared with the reference image to determine whether there are no defects, short circuits, wires, etc. in the wiring pattern. Inspection of wide abnormalities, adhesion of foreign matter, etc. (so-called appearance inspection. It may also be called pattern inspection, microscopic inspection) (for example, Patent Document 1).

On the other hand, a visual inspection (so-called macroscopic inspection) is performed to see whether there are no relatively large-sized damage, contamination, or adhesion of foreign matter (for example, Patent Document 2). [Prior technical literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2007-155610 [Patent Document 2] Japanese Patent Application Laid-Open No. 9-186209

[Problem to be solved by the invention]

Like microscopic inspection, macroscopic inspection also seeks to automate the inspection device. However, previous automatic inspection devices are specialized for microscopic inspection and are not suitable for inspection across multiple wafers. They are unable to inspect relatively large-sized damage or contamination, adhesion of foreign matter, etc., which are within the scope of macroscopic inspection.

Therefore, the present invention was completed in view of the above-mentioned problems. The object is to provide an inspection device and method that can automatically inspect relatively large-sized damage, contamination, adhesion of foreign matter, etc., which are within the scope of macroscopic inspection, based on an enlarged image of a small area obtained for microscopic inspection. [Technical means to solve problems]

In order to solve the above problems, one aspect of the present invention is a wafer appearance inspection device. This involves taking an appearance image of a repeating pattern formed on the wafer to be inspected or a pattern-free area set on the wafer to be inspected, and comparing the captured image with a pre-registered reference image to perform the inspection. And have: A camera unit that captures the inspection target parts set for each of repeated patterns or non-pattern areas; The image processing unit processes the images captured by the camera unit; a reference image registration unit that pre-registers a reference image, which is a criterion for determining whether the image of the inspection target part is good or bad; and A comparison inspection unit that compares the inspection image captured of the inspection target part with the reference image to inspect defects hidden in the inspection target part; and The Comparative Inspection Department has: Microscopic inspection mode, which detects defects hidden in the inspection target parts; and Macroscopic inspection mode, which spans multiple inspection target parts and inspects potential defects in the inspection target wafer.

Furthermore, another aspect of the present invention is a wafer appearance inspection method, This involves taking an appearance image of a repeating pattern formed on the wafer to be inspected or a pattern-free area formed on the wafer to be inspected, and comparing the captured image with a pre-registered reference image to perform the inspection. This wafer visual inspection method uses: a wafer holding mechanism that holds the wafer; A camera mechanism that captures specific ranges set for each of repeating patterns or non-patterned areas; a relative movement mechanism that relatively moves the wafer holding mechanism and the camera mechanism; and The image processing mechanism processes the images captured by the camera mechanism; and the wafer appearance inspection method has the following steps: Maintain the reference wafer that becomes the inspection reference; While changing the imaging location one by one, the repeating pattern formed on the reference wafer or the pattern-free area formed on the reference wafer is divided and photographed, and the divided and photographed reference images are joined together to create a large-sized macro inspection. After generating the reference image, compress the large-sized reference image for macroscopic inspection to generate a small-sized reference image for macroscopic inspection; Keep the wafer under inspection; While changing the imaging location one by one, the repeating pattern formed on the inspection target wafer or the non-pattern area formed on the inspection target wafer is divided and photographed, and the inspection images captured by the divisions are joined together to create a large-sized macro After the inspection image is generated, the large-size macro-inspection inspection image is compressed to generate a small-size macro-inspection inspection image; and The small-sized inspection image for macro-inspection is compared with the small-sized reference image for macro-inspection, and the inspection target wafer is macro-inspected.

According to this wafer appearance inspection device and method, it is possible to automatically inspect relatively large-sized damage or contamination, adhesion of foreign matter, etc., which are within the scope of macroscopic inspection, based on the enlarged image of a small area obtained for microscopic inspection. [Effects of the invention]

With one inspection device, both micro-inspection and macro-inspection can be automatically performed.

Hereinafter, modes for implementing the present invention will be described using the drawings. In addition, in the following explanation, the three axes of the orthogonal coordinate system are represented as x, y, and z, the horizontal direction is represented as the x direction and the y direction, and the direction perpendicular to the xy plane (i.e., the gravity direction) is represented as z direction. In addition, the z direction represents the direction opposite to gravity as upward, and the direction of gravity as downward. Also, let the direction of rotation with the z direction as the central axis be the θ direction.

FIG. 1 is a schematic diagram showing the overall structure of an example of an embodiment of the present invention. FIG. 1 schematically shows each component constituting the wafer appearance inspection device 1 of the present invention.

The wafer appearance inspection apparatus 1 photographs the repeated appearance pattern of the device wafer C formed on the inspection target wafer W, compares it with the reference image Pf, and inspects the inspection target wafer W and the device wafer C.

Specifically, the wafer appearance inspection device 1 sequentially changes the imaging position of the imaging area F set on the inspection target wafer W, takes an entire image of the inspection target part over the wafer W, and processes the captured image. The inspection image Px is generated. Then, by comparing the inspection image Px with the reference image Pd, it is automatically determined whether the circuit pattern of the device wafer C has no short circuits, disconnections, etc., or whether there are no foreign matter or defects attached to the entire wafer W. Desired inspection (i.e. microscopic inspection). Furthermore, the wafer appearance inspection apparatus 1 processes the inspection image Px (so-called segmented image) to generate an inspection image Pm for macro inspection (so-called whole image), and combines the inspection image Pm for macro inspection with the preset image. The registered macroscopic inspection is compared with the reference image Pf, and the macroscopic inspection of the entire wafer W is automatically performed.

More specifically, the wafer appearance inspection apparatus 1 includes a wafer holding unit 2, an imaging unit 3, a relative movement unit 4, a wafer layout registration unit 5, a reference image registration unit 6, an image processing unit 7, and a comparison inspection unit. 8. And the control department CN, etc.

The wafer holding unit 2 holds the wafer W. Specifically, the wafer holding portion 2 supports the wafer W while maintaining a horizontal state from the lower surface side. More specifically, the wafer holding part 2 includes a mounting table 20 with a horizontal upper surface. The mounting table 20 is provided with grooves and holes in portions in contact with the wafer W, and these grooves and holes are connected to a negative pressure generating mechanism such as a vacuum pump through a switching valve or the like. Furthermore, the wafer holding portion 2 can hold or release the wafer W by switching the groove portion and the hole portion to a negative pressure state or an atmosphere release state.

The imaging unit 3 captures an inspection target part and captures an image including the inspection target part.

Here, the image including the inspection target part means an image captured including a part or all of the repeating appearance pattern of the device wafer C to be inspected, which is formed on the inspection target wafer W, and refers to the image captured. The image captured by dividing the inspection target part of each device wafer C (that is, setting a plurality of imaging areas F inside and outside the inspection target part of each device wafer C), capturing an image including one or a plurality of device wafers An image of a wide range of the inspection target part of C (that is, in the imaging area F, one or a plurality of inspection target parts are set for each device wafer C). In addition, since the arrangement (number, pitch, etc.) of the device wafers C and the required inspection accuracy are different for each inspection type, the size, position, interval, etc. of the range captured by the imaging unit 3 (i.e., the imaging area) Log in appropriately for each examination type.

Specifically, the imaging unit 3 includes a lens barrel 30, an illumination unit 31, a half mirror 32, a plurality of objective lenses 33a and 33b, a rotator mechanism 34, an imaging camera 35, and the like.

The lens barrel 30 fixes the lighting part 31, the half mirror 32, the objective lenses 33a, 33b, the rotator mechanism 34, the imaging camera 35, etc. in a specific posture, and guides the illumination light and the observation light. The lens barrel 30 is attached to the device frame 1f via connecting metal fittings or the like (not shown).

The lighting unit 31 emits illumination light L1 required for photography. Specifically, the lighting unit 31 may be a laser diode, a metal halide lamp, a xenon lamp, or LED lighting.

The half mirror 32 reflects the illumination light L1 emitted from the illumination unit 31 and irradiates it toward the wafer W side, and allows the light (reflected light, scattered light) L2 incident from the wafer W side to pass toward the imaging camera 35 side.

The objective lenses 33a and 33b form an image of the imaging area on the workpiece W on the imaging element 36 of the imaging camera 35 at specific observation magnifications that are different from each other.

The rotator mechanism 34 uses or switches any one of the objective lenses 33a and 33b. Specifically, the rotator mechanism 34 is controlled by manual or external signals to rotate and stop at a specific angle.

The imaging camera 35 captures the imaging area F on the workpiece W, and acquires an image formed on the imaging element 36 . The acquired image is output to the outside as an image signal and image data, and is processed by the image processing unit 7 to generate an inspection image Px and a reference image Pd. In addition, since these inspection images Px and reference images Pd are taken by dividing the workpiece W into each specific divided area, rather than taking a wide range of batches of the entire workpiece W, they are intentionally divided. The photographed inspection image Px, and the divided and photographed reference image Pd.

The relative movement unit 4 relatively moves the wafer holding unit 2 and the imaging unit 3 . Specifically, the relative movement unit 4 includes an x-axis slider 41 , a y-axis slider 42 , and a rotation mechanism 43 .

The x-axis slider 41 is installed on the device frame 1f, so that the y-axis slider 42 moves at any speed in the x-direction and remains stationary at any position. Specifically, the x-axis slider is composed of a pair of rails extending in the x-direction, a slider portion that moves on the rails, and a slider driving portion that moves and stops the slider portion. The slide driving part may include a combination of a servo motor or a pulse motor and a ball screw mechanism that rotates or stops under the control of a signal from the control part CN, or a linear motor mechanism. In addition, the x-axis slider 41 is equipped with an encoder for detecting the current position and movement amount of the slider portion. Examples of the encoder include a linear member called a linear scale with fine irregularities carved at a specific pitch, a rotary encoder that detects the rotation angle of a motor that rotates a ball screw, and the like.

The y-axis slider 42 causes the rotating mechanism 43 to move in the y direction at any speed and to stop at any position based on the control signal output from the control unit CN. Specifically, the y-axis slider is composed of a pair of rails extending in the y direction, a slider portion that moves on the rails, and a slider driving portion that moves and stops the slider portion. The slide driving part may include a combination of a servo motor or a pulse motor and a ball screw mechanism that rotates or stops under the control of a signal from the control part CN, or a linear motor mechanism. Furthermore, the y-axis slider 42 is provided with an encoder for detecting the current position and movement amount of the slider portion. Examples of the encoder include a linear member called a linear scale with fine irregularities carved at a specific pitch, a rotary encoder that detects the rotation angle of a motor that rotates a ball screw, and the like.

The rotation mechanism 43 rotates the mounting table 20 in the θ direction at an arbitrary speed and stops it at an arbitrary angle. Specifically, the rotating mechanism 43 can be rotated/stationary at any angle by control of a signal from an external device such as a direct drive motor. The mounting table 20 of the wafer holding part 2 is mounted on the member on the rotating side of the rotating mechanism 43 .

Since the relative moving unit 4 has such a structure, while holding the wafer W to be inspected, the wafer W can be moved at a specific speed or angle in the xyθ direction with respect to the imaging unit 3 independently or compositely. Move relative to each other, or remain stationary at any position or angle.

FIG. 2 is a conceptual diagram showing a shooting situation of an example of the embodiment of the present invention. As shown in FIG. 2 , the camera 35 of the imaging unit 3 is relatively moved relative to the wafer W in the direction indicated by the arrow Vs, and a plurality of device wafers C (2, 1) to be arranged separately on the wafer W are sequentially changed. In the imaging location C(5,1), the inspection target part (i.e., the divided imaging wafer W) is photographed on one side. In addition, the figure shows a situation in which the imaging area F including the inspection target portion of the device wafer C ( 4 , 1 ) is imaged and photographed by the imaging element of the imaging camera 35 at the current time.

FIG. 3 is a plan view showing an arrangement example of a reference wafer Wf, a wafer W to be inspected, and a device wafer C as an example of the embodiment of the present invention. FIG. 3(a) shows a reference wafer Wf serving as an inspection reference and an arrangement image of a repeating appearance pattern of a device chip C formed on the reference wafer Wf. In addition, the positional relationship between the reference image Pd captured by dividing the reference wafer Wf and the device wafer C is shown in FIG. 3(a) . FIG. 3(b) shows an arrangement image of a repeating appearance pattern of a device wafer C formed on a wafer W to be inspected, and an example of contamination X hidden in the wafer W. In addition, the positional relationship between the inspection image Px captured by dividing the wafer W and the device wafer C is shown in FIG. 3(b). In addition, the contamination X hidden in the wafer W is one type of defect that is the detection target of the macroscopic inspection, and is widely distributed across the inspection images Px captured by a plurality of divisions.

The wafer layout registration unit 5 registers the wafer layout that specifies the arrangement information of the device chip C of the wafer W with respect to the reference posture and reference position of the wafer.

In addition, in the wafer layout, the state in which the notch Wk of the wafer W faces directly downward is set as the reference posture, and the center of the wafer W in this posture is set as the reference position in the xy direction (also called the origin). The vertical and horizontal arrangement, pitch, offset information, etc. (i.e., configuration information) of the repeated appearance pattern of the device chip C are specified.

Specifically, in the wafer layout registration unit 5, data specifying the wafer layout for each inspection type is registered. Therefore, if imaging is performed based on the wafer layout, divided imaging can be performed to obtain the reference image Pd and the inspection image Px as shown in FIG. 3 .

The reference image registration unit 6 registers a reference image serving as a reference for inspection. Specifically, the reference image registration unit 6 registers the divided and photographed reference image Pd (so-called divided image) and the small-sized reference image Pf for macroscopic inspection (so-called whole image).

The reference image Pd captured by division is a reference indicating that the repeating appearance pattern of the device wafer C formed on the wafer W is normal. Specifically, the reference image Pd captured by segmentation is the subject of comparison with the inspection image Px captured by segmentation under microscopic inspection, and is the basis for making the following determinations for each pixel and pixel group: : If the difference or variance value of the brightness value is within the preset range, it is judged as normal, if it is outside the range, it is judged as abnormal. More specifically, the reference image Pd may exemplify one image representing a pre-selected good product image, an image in which a plurality of good product images are selected in advance and averaged, or an image generated based on a good product learning method. Like etc.

On the other hand, the small-sized reference image Pf for macroscopic inspection is a reference indicating that the wafer W is in a normal state as a whole. Specifically, in the reference image registration unit 6, data of the small-size reference image Pf is registered for each inspection type.

The image processing unit 7 processes the image captured by the imaging unit 3 . Specifically, the image processing unit 7 has a function of acquiring an image captured by the imaging camera 35 of the imaging unit 3 and extracting (also called correction) a portion required for inspection from the imaging area F. The process of generating the inspection image Px and the reference image Pd, or the process of joining a plurality of divided images to generate a single image, or the compression process (omitting to reduce the number of pixels constituting the image and lowering the resolution) The processing of resolution such as scaling, or reducing the brightness value, etc.). Furthermore, the image processing unit 7 is configured to have a function of performing processing such as tilt correction, brightness correction, shading correction, image curvature correction, etc., and performs processing appropriately.

More specifically, the image processing unit 7 joins the divided and photographed reference images Pd to generate one overall image (that is, a large-size reference image PF for macro inspection), or combines the divided and photographed inspection images Px are combined to generate one overall image (that is, a large-sized inspection image PM for macro inspection). Furthermore, the image processing unit 7 performs compression processing on the large-size reference image PF for macro-inspection to generate a small-size reference image Pf for macro-inspection, and performs compression processing on the large-size inspection image PM for macro-inspection to generate Small-sized inspection image Pm for macro inspection.

FIG. 4 is an image diagram showing an image of a large-sized macroscopic inspection image as an example of an embodiment of the present invention. FIG. 4( a ) illustrates an image of a large-sized reference image PF for macroscopic inspection, and FIG. 4( b ) illustrates an image of a large-sized inspection image PM for macroscopic inspection. In addition, the large-sized inspection image PM for macroscopic inspection contains contamination X hidden in the wafer W.

FIG. 5 is an image diagram showing a small-sized macroscopic inspection image and a differential image as an example of an embodiment of the present invention. FIG. 5( a ) illustrates an image of the small-sized reference image Pf for macroscopic inspection, and FIG. 5( b ) illustrates an image of the small-sized inspection image Pm for macroscopic inspection. In addition, the small-sized inspection image Pm for macroscopic inspection includes contamination X hidden in the wafer W. FIG. 5(c) illustrates an image obtained by comparing the small-sized inspection image Pm for macroscopic inspection and the small-sized reference image Pf for macroscopic inspection (that is, differencing the brightness values).

The comparison inspection unit 8 compares the inspection image Pm for macro inspection generated by the image processing unit 7 with the reference image Pf for macro inspection, and inspects the inspection target part. Specifically, the image processing unit 7 compares the corresponding pixels of the inspection image Pk of the inspection target part including the repeated appearance pattern of the device wafer C with the reference image Pf, and determines whether the brightness of each pixel or pixel group is If the difference or variance value of the value is within the preset range, it is judged to be normal, and if it is outside the range, it is judged to be abnormal.

Therefore, in the image processing unit 7, the inspection image Pk and the reference image Pf are compared, and the contamination X can be detected (that is, macroscopically inspected) by extracting a portion where the difference in brightness value is outside the reference range.

The chip layout registration part 5, the reference image registration part 6, the image processing part 7, and the comparison inspection part 8 of the present invention are composed of a computer CP (i.e., hardware) with an image processing function, and its execution program (i.e., software). ) constitute. More specifically, the chip layout registration unit 5 and the reference image registration unit 6 are composed of a part of a memory unit (register, memory, etc.) or a recording medium (HDD, SSD, etc.) of the computer CP. The image processing unit 7 is composed of an image processing unit (so-called GPU) of the computer CP. The comparison inspection unit 8 is composed of a calculation processing unit and an execution program of the computer CP.

Computer CP, for example, assumes the following functions and roles: ・Register information such as imaging magnification and imaging position, imaging path T, imaging interval (pitch, time interval), feed speed, etc. for each inspection type (so-called inspection steps) ・Register the inspection conditions for each inspection type (the normal range of the brightness value and variance value of the inspection target part, etc.) ・Connect with user interface (keyboard, SW, monitor, etc.) to input and output various information ・Connect with the control unit CN or an external host computer to input and output signals or data In addition, the inspection steps and inspection conditions of each inspection type are also called prescription information and inspection prescriptions.

The control unit CN is responsible for the following functions and effects, for example: ・Outputs a signal for holding/releasing the wafer W to the wafer holding unit 2 ・Control the rotator mechanism 34 to switch the objective lens (imaging magnification) used ・Outputs a light emission trigger to the lighting unit 31 ・Output imaging trigger to camera 35 ・Driving control of the relative moving part 4: Monitors the current positions of the x-axis slider 41, the y-axis slider 42, and the rotating mechanism 43, and outputs a driving signal ・Output the current position information of the relative moving part 4 (x-axis slider 41, y-axis slider 42, and rotation mechanism 43) to the computer CP ・Control each department based on inspection prescriptions

In addition, the imaging trigger is output from the control unit 9 to the imaging unit 3 in the following manner: ・The imaging unit 3 is scanned and moved in the x direction, and the illumination light L1 is emitted for a very short time every time it moves a specific distance (so-called stroboscopic light emission). ・Or, the imaging unit 3 is moved to a specific position and held still, and the illumination light L1 is irradiated to perform imaging (so-called step-and-repeat type).

In addition, the imaging trigger means an instruction to capture an image to the imaging camera 35 and the image processing unit 7 , an instruction to emit the illumination light L1 , and the like. Specifically, as the imaging trigger, (Case 1) the illumination light L1 is stroboscopically emitted during the time that the imaging camera 35 can take pictures (so-called exposure time), or (Case 2) the illumination light L1 is irradiated Take photos within the time limit. Alternatively, the imaging trigger is not limited to an instruction to the imaging camera 35, but may be (case 3) an image capture instruction to the image processing device that acquires the image. In this way, it can also correspond to the form in which the self-imaging camera 35 outputs image signals or image data one after another.

More specifically, the control unit CN is composed of a computer or a programmable logic controller (i.e., hardware), and its execution program (i.e., software).

[Benchmark image registration and inspection process] FIG. 6 is a flow chart illustrating an example of the embodiment of the present invention. In FIG. 6( a ), the steps for registering the macro-inspection reference image Pf for macro-inspection of the wafer W using the wafer appearance inspection apparatus 1 are shown step by step as a series of flows. In addition, by logging in to the execution program of the computer CP or the control unit CN, the series of processes can be executed. In FIG. 6( b ), as a series of processes, the steps of photographing and inspecting the device wafer C arranged on the wafer W using the wafer appearance inspection device 1 are shown in each step.

Before inspection, follow the steps below to generate a reference image for macroscopic inspection and register it in advance. The mode in which this series of processes is performed is called "reference image generation mode for macroscopic inspection".

First, a registered recipe is selected and the reference wafer Wf is placed on the mounting table 20 (step s1). Then, the reference wafer Wf is aligned (step s2).

The reference image Pd is captured while relatively moving the reference wafer Wf (step s3), and the reference image Ps is registered in the reference image registration unit 6 (step s4).

Then, it is determined whether the entire reference wafer Wf has been imaged (step s5). If the image has not been completed, the above-mentioned steps s2 to s5 are repeated. On the other hand, when the imaging is completed, the reference images Pd are combined to generate a large-size reference image PF for macroscopic inspection, and the reference image PF is compressed to generate a small-sized reference image Pf for macroscopic inspection ( Step s6). Then, the reference image Pf is registered in the reference image registration unit 6 (step s7).

Then, the reference wafer Wf is transferred out (step s8), and it is determined whether to perform the same process on the next reference wafer Wf (step s9). If the same processing is performed, the above-mentioned steps s2 to s9 are repeated. If the same processing is not performed, the series of processes is ended.

The following explains the procedures for performing normal inspections "microscopic inspection/macroscopic inspection mode".

First, the inspection prescription is selected, the inspection mode and order of the wafer W are determined, and the wafer W to be inspected is placed on the mounting table 20 (step s11). Then, the wafer W to be inspected is aligned (step s12).

The inspection image Px is captured while relatively moving the wafer W to be inspected (step s13). It is determined whether to perform microscopic inspection (step s14). If microscopic inspection is performed, microscopic inspection is performed on each inspection image Px based on the pre-registered inspection standards (step s15).

Then, it is determined whether the entire wafer W has been imaged (step s16). If the image has not been completed, the above steps s12 to s16 are repeated. On the other hand, when the imaging is completed, it is determined whether to perform a macro inspection (step s20). When performing a macroscopic inspection, the small-sized inspection image Pm for macroscopic inspection is compared with the small-sized reference image Pf for macroscopic inspection based on a pre-registered inspection standard, and the macroscopic inspection is performed (step s21).

Then, the wafer W to be inspected is transmitted (step s30), and it is determined whether to perform the same process on the wafer W to be the next inspection object (step s31). If the same processing is performed, the above-mentioned steps s12 to s31 are repeated. If the same processing is not performed, the series of processes is ended.

According to the wafer appearance inspection device 1 and the wafer appearance inspection method of the present invention, it is possible to automatically inspect relatively large-sized damage or damage that is a category of macro inspection based on an enlarged image of a smaller area obtained for micro inspection. Contamination, adhesion of foreign matter, etc. Therefore, with one inspection device, both microscopic inspection and macroscopic inspection can be automatically performed.

[Example of changes] In the above, the wafer appearance inspection apparatus 1 is provided with the "reference image generation mode for macroscopic inspection" as an example. With this configuration, it is preferable that a single inspection device can generate and register a small-sized reference image Pf for macroscopic inspection and perform macroscopic inspection.

However, it is possible to adopt a configuration in which the wafer appearance inspection apparatus 1 does not have a "reference image generation mode for macroscopic inspection", and the wafer appearance inspection device 1 can be configured to use an external recording medium (HDD, SSD, memory card, etc.) or an electrical communication line, etc. , output the segmented and photographed reference image Pd to an external computer or processing system, etc., use the external computer or processing system, etc. to generate a large-size reference image PF for macroscopic inspection, and generate a small-sized reference image for macroscopic inspection. Like Pf. In this case, the generated small-sized reference image Pf for macro inspection is transferred to the wafer appearance inspection device 1 via an external recording medium (HDD, SSD, memory card, etc.) or an electrical communication line, and is logged in. in the reference image registration section 6. With this configuration, both microscopic inspection and macroscopic inspection can be performed with one inspection device.

In addition, in the above, as an example, the wafer appearance inspection apparatus 1 captures an appearance image of the repeated appearance pattern of the device wafer C formed on the inspection target wafer W, compares it with the reference image Pf, and performs the inspection on the inspection target wafer W. Circle W and the composition and steps of inspection of the device wafer C. However, when applying the present invention, the inspection object is not limited to the repeated appearance pattern of the device chip C formed on the wafer W, but may be a pattern-free area set on the wafer W. In this case, as the reference image Pd, a reference indicating that the non-patterned area set on the wafer W is in a normal state is registered in advance. Then, the imaging unit 3 captures an image of a pattern-free area set on the wafer W to be inspected, and the comparison inspection unit 8 performs inspection in the same procedure as described above.

1: Wafer appearance inspection device 1f:Device frame 2: Wafer holding part 3:Camera Department 4: Relative movement part 5: Chip layout registration department 6: Reference image registration part 7:Image processing department 8: Comparative Inspection Department 20: Loading platform 30: Lens tube 31:Lighting Department 32: Half mirror 33a,33b:Objective lens 34:Rotator mechanism 35:Video camera 36:Camera components 41:x-axis slider 42:y-axis slider 43: Rotating mechanism C: device wafer C(2,1)～C(5,1): device wafer CN:Control Department CP:Computer F:Camera area L1: illumination light L2: Light incident from the wafer side (reflected light, scattered light) Pd: reference image captured by segmentation PF: Reference image for macroscopic examination (large size) Pf: Reference image for macroscopic examination (small size) PM: Inspection image for macro inspection (large size) Pm: Inspection image for macro inspection (small size) Px: captured inspection image Vs:arrow W: Wafer (inspection object)/workpiece Wk: gap Wf: reference wafer X: Detection object (pollution, etc.) x: axis/direction y: axis/direction z: axis/direction θ: direction

FIG. 1 is a schematic diagram showing the overall structure of an example of an embodiment of the present invention. FIG. 2 is a conceptual diagram showing a photographing aspect of an example of the embodiment of the present invention. 3(a) and 3(b) are plan views showing an arrangement example of a reference wafer, a wafer to be inspected, and a device wafer as an example of the embodiment of the present invention. FIGS. 4(a) and 4(b) are image diagrams showing images of a large-sized macroscopic inspection image as an example of an embodiment of the present invention. FIGS. 5(a) to 5(c) are image diagrams showing small-sized macroscopic inspection images and differential images, which are examples of embodiments of the present invention. 6(a) and (b) are flowcharts illustrating an example of the embodiment of the present invention.

1: Wafer appearance inspection device

1f:Device frame

2: Wafer holding part

3:Camera Department

4: Relative movement part

6: Reference image registration part

7:Image processing department

8: Comparative Inspection Department

20: Loading platform

30: Lens tube

31:Lighting Department

32: Half mirror

33a,33b:Objective lens

34:Rotator mechanism

35:Video camera

36:Camera components

41:x-axis slider

42:y-axis slider

43: Rotating mechanism

C: device wafer

CN:Control Department

CP:Computer

F:Camera area

L1: illumination light

L2: Light incident from the wafer side (reflected light, scattered light)

Pd: reference image captured by segmentation

PF: Reference image for macroscopic examination (large size)

Pf: Reference image for macroscopic examination (small size)

PM: Inspection image for macro inspection (large size)

Pm: Inspection image for macro inspection (small size)

Px: captured inspection image

W: Wafer (inspection object)/workpiece

θ: direction

Claims (2)

A wafer appearance inspection device that captures an appearance image of a repeating pattern formed on a wafer to be inspected or a pattern-free area set on a wafer to be inspected, and compares the captured image with a pre-registered reference image A device for comparing and inspecting is characterized by having: a camera unit that photographs an inspection target part set for each of the aforementioned repeating pattern or the aforementioned non-pattern area; and an image processing unit that processes the image captured by the aforementioned camera unit. image processing; a reference image registration unit that registers the reference image in advance, which is a criterion for determining whether the image of the inspection target part is good or bad; and a comparison inspection unit that photographs the inspection object The inspection image of the part is compared with the aforementioned reference image, and the defects hidden in the inspection object part are inspected; and the aforementioned comparative inspection unit has: a microscopic inspection mode, which inspects the defects hidden in the inspection object part; and a macro inspection. mode, which spans a plurality of the aforementioned inspection target locations to inspect potential defects in the aforementioned inspection target wafer; and the aforementioned wafer appearance inspection device is equipped with a reference image generation mode for macro inspection, and this mode is before executing the aforementioned macro inspection mode. Generate a macro-inspection reference image, which is a quality judgment standard for detecting potential defects in the inspection target wafer; and in the macro-inspection reference image generation mode, the macro-inspection reference image is generated by the aforementioned imaging The mechanism divides and photographs the repeating pattern formed on the reference wafer that serves as the inspection reference or the pattern-free area set on the reference wafer, and the aforementioned image processing unit joins the divided and photographed reference images to generate a large-scale image. After generating a large-size reference image for macro-inspection, the large-size reference image for macro-inspection is compressed to generate a small-size reference image for macro-inspection, and the aforementioned small-size reference image for macro-inspection is pre-registered in The reference image registration unit; in the macro inspection mode, the imaging mechanism divides and photographs the repeating pattern or the pattern-free area, and the image processing unit joins the divided and photographed inspection images to each other. After the large-size inspection image for macro inspection is generated, the large-size inspection image for macro inspection is compressed to generate a small-size inspection image for macro inspection; the aforementioned comparison inspection unit compresses the aforementioned small-size inspection image. The inspection image for macro inspection is compared with the aforementioned small-sized reference image for macro inspection, and potential defects in the aforementioned inspection target wafer are inspected. A wafer appearance inspection method that captures an appearance image of a repeating pattern formed on a wafer to be inspected or a pattern-free area set on a wafer to be inspected, and compares the captured image with a pre-registered reference image The method for performing inspection by comparison is characterized by using: a wafer holding mechanism that holds the wafer to be inspected; a camera mechanism that captures a specific range set for each of the repeating pattern or the non-pattern area; and relative movement. a mechanism that relatively moves the wafer holding mechanism and the camera mechanism; and an image processing mechanism that processes the images captured by the camera mechanism; and The wafer appearance inspection method has the following steps: holding a reference wafer as an inspection standard; and sequentially changing the imaging location while dividing and photographing a repeating pattern formed on the reference wafer or a pattern-free area formed on the reference wafer. After the divided and photographed reference images are joined together to generate a large-size reference image for macroscopic inspection, the large-sized reference image for macroscopic inspection is compressed to generate a small-sized reference image for macroscopic inspection; the above is maintained. The wafer to be inspected; while changing the imaging location one after another, the repeating pattern formed on the wafer to be inspected or the non-pattern area formed on the wafer to be inspected is divided and photographed, and the inspection images captured by the divisions are mutually photographed. After combining to generate a large-size inspection image for macro-inspection, compress the large-size inspection image for macro-inspection to generate a small-size inspection image for macro-inspection; and combine the aforementioned small-size inspection image for macro-inspection The wafer to be inspected is macroscopically inspected by comparison with the small-sized reference image for macroscopic inspection.