JP7627101B2 - Appearance inspection device and method - Google Patents

Description

The present invention relates to an appearance inspection apparatus and method for inspecting an area to be inspected by comparing an inspection image of the area to be inspected with a reference image. For example, the present invention relates to a wafer appearance inspection apparatus and method for imaging the appearance of semiconductor devices formed on a wafer and determining whether the semiconductor devices are good or bad.

Semiconductor devices are formed by stacking many semiconductor device circuits (i.e., the repeating external pattern of device chips) in layers on a single semiconductor wafer, which is then singulated into individual chip components, which are then packaged and shipped as individual electronic components or incorporated into electrical products.

Then, before the individual chip components are separated, an inspection image of the repeating appearance pattern of the device chips formed on the wafer is compared with a reference image to inspect the quality of each chip component (for example, Patent Document 1).

In addition, a technique is known that reduces false detections due to misalignment by aligning the inspection target image with the reference image before detecting defects (for example, Patent Document 2).

On the other hand, there is a known technique for subtracting (i.e., comparing) an inspection image and a reference image, and masking and erasing noise that occurs due to deviations in pattern matching at the image boundaries (see, for example, Patent Document 3).

JP 2007-155610 A JP 2003-4427 A JP 2000-335062 A

The semiconductor device to be inspected contains multiple adjacent regions with different properties. For example, when inspecting chip components, wiring circuit patterns and external connection terminals (so-called electrode pads and lands) are formed on the surface of the wafer.

This wiring circuit pattern is deeply related to the performance of the device chip, so it requires rigorous inspection for breaks, shorts, differences in line width, and the presence of foreign matter.

On the other hand, because external connection terminals only need to be able to connect and conduct with external devices and lead wires, there is no requirement for strictness in terms of misalignment of the outer edges or dimensional errors as with wiring circuit patterns.

Therefore, if an inspection image of an inspection target area contains an area (variable area) where positional deviation of the outer edge or dimensional error is permitted, the position of the boundary (i.e., outer edge) with the surrounding area (peripheral area) will vary for each inspection image. When this happens, when compared with a reference image, the area in the inspection image where the position of the outer edge varies will be detected as a defect (so-called pseudo defect), which will be a factor in reducing the yield rate of device chips.

Furthermore, conventional techniques such as those described in Patent Documents 2 and 3 are based on the assumption that the size, range, pattern, etc. of the reference image are constant, and cannot accommodate cases where the dimensions of the area to be inspected vary.

Therefore, the present invention has been made in consideration of the above problems,
To provide an appearance inspection device and method capable of obtaining desired inspection results without detecting false defects even if an inspection target area includes a variable area in which positional deviation of the outer edge and dimensional errors are allowed.

In order to solve the above problems, one aspect of the present invention is to
An appearance inspection apparatus that captures and inspects the appearance of an inspection target portion,
an inspection image acquisition unit that acquires an appearance image of the inspection target portion as an inspection image; and an inspection reference image registration unit that registers a reference image that serves as a reference for inspection of the inspection target portion.
an inspection unit that compares the inspection image with a reference image and inspects the inspection target area;
The area to be inspected includes a variable area where deviations in the outer edge position and dimensional errors are allowed.
an edge detection unit that processes the inspection image and detects the position of an outer edge of a variation region;
A variable region reference image serving as a reference for inspection of the variable region is registered as a reference image, in which the outer edge of the variable region is set to a range wider than a standard range in which positional deviation or dimensional error of the outer edge is not permitted,
The Inspection Department:
The variation region in the inspection image is compared with a region in the variation region reference image, the position of which corresponds to that of the variation region, based on the position of the outer edge detected by the edge detection unit, to inspect the variation region; and
The surrounding area in the inspection image is compared with an area in the surrounding area reference image whose position corresponds to that of the surrounding area based on the position of the outer edge of the variable area detected by the edge detection unit, and the surrounding area is inspected.

Another aspect of the present invention is
1. A visual inspection method for inspecting an inspection target part by comparing an inspection image obtained by capturing an appearance of the inspection target part with a reference image, comprising the steps of:
A reference image registration step of registering a reference image in advance;
An inspection image acquisition step of acquiring an inspection image;
an inspection step of comparing the inspection image and the reference image to inspect the inspection target portion;
The area to be inspected includes a variable area where deviations in the outer edge position and dimensional errors are allowed.
registering a variable region reference image as a reference image, the variable region being set to a range wider than a standard range in which positional deviation or dimensional error of the outer edge is not permitted, and serving as a reference for inspection of the variable region;
an edge detection step for processing the inspection image to detect the location of an outer edge of a variation region;
In the inspection step, the variation region in the inspection image is compared with a region in the variation region reference image, the region corresponding to the variation region in position based on the position of the outer edge detected in the edge detection step, to inspect the variation region, and further
The surrounding area in the inspection image is compared with an area in the surrounding area reference image whose position corresponds to that of the surrounding area based on the position of the outer edge of the variable area detected in the edge detection step, and the surrounding area is inspected.

Even if the area to be inspected contains variable areas where misalignment of the outer edge or dimensional errors are permitted, the desired inspection results can be obtained without detecting false defects.

FIG. 2 is an image diagram showing an example of an inspection image in an example of an embodiment of the present invention. 1 is a schematic diagram showing an overall configuration of an example of an embodiment of the present invention; FIG. 1 is a conceptual diagram showing how an exterior image is captured in an example of an embodiment of the present invention. FIG. 2 is an image diagram showing an example of a reference image in an example of an embodiment of the present invention. FIG. 1 is a flow diagram of an example of an embodiment of the present invention.

Below, an embodiment of the present invention will be described with reference to the drawings. In the following description, the three axes of the Cartesian coordinate system are designated as X, Y, and Z, the horizontal direction is referred to as the X direction and the Y direction, and the direction perpendicular to the XY plane (i.e., the direction of gravity) is referred to as the Z direction. In addition, the direction against gravity in the Z direction is referred to as up, and the direction in which gravity acts is referred to as down. The direction of rotation around the Z direction as the central axis is referred to as the θ direction.

FIG. 1 is an image diagram showing an example of an inspection image in an example of an embodiment of the present invention.
FIG. 1 shows an example of an examination image Px obtained by capturing an examination target region Rx.
The inspection target region Rx includes a variable region Rx1 in which positional deviation and dimensional error of the outer edge B are permitted, and a peripheral region Rx2 adjacent to the variable region Rx1.

In the following explanation, an example is shown in which, in a device chip C formed on a wafer W, an external connection terminal formed in a plating process is set as a variable region Rx1 in the inspection target area Rx, and a wiring circuit pattern or the like is set as a peripheral region Rx2 in the inspection target area Rx.

Figure 2 is a schematic diagram showing the overall configuration of an example of a form that embodies the present invention. Figure 2 shows a schematic diagram of each part that constitutes the wafer visual inspection device 1 according to the present invention.

The wafer visual inspection device 1 inspects the appearance of an inspection target area Rx set on the surface of a wafer W by capturing an image of the appearance. For example, it is configured to acquire an inspection image Px while sequentially capturing an image of a repeating appearance pattern of a device chip C (a type of semiconductor device) formed on the wafer W at a predetermined pitch in the XY directions, and to continuously inspect the entire surface of the wafer W by comparing it with a reference image Pf registered in advance. Specifically, the wafer visual inspection device 1 includes an inspection image acquisition unit 2, an inspection reference image registration unit 3, an edge detection unit 4, an inspection unit 5, etc.

More specifically, the wafer visual inspection device 1 includes a wafer holding unit H, an imaging unit S, a relative movement unit M, a computer CP, a controller CN, etc.

The inspection image acquisition unit 2 acquires an external image of the inspection target area Rx as an inspection image Px. Specifically, the inspection image acquisition unit 2 is composed of an imaging unit S and an input unit of a computer CP.

Figure 3 is a conceptual diagram showing how to capture an external image in one example of a form that embodies the present invention. Figure 3 shows how the imaging camera S5 of the imaging unit S moves relative to the wafer W in the direction indicated by the arrow Vs, sequentially capturing images of the external appearance of device chips C formed on the wafer W at a predetermined pitch in the XY directions.

Specifically, during the relative movement of the relative moving part M (for example, movement in the direction of the arrow Vs), the illumination part S1 is strobed at predefined intervals or positions, and an external image similar to a still image is captured by the imaging camera S5. Then, the external image output from the imaging camera S5 is input as the inspection image Px to the input part of the computer CP (i.e., the inspection image Px is acquired).

The inspection reference image registration unit 3 registers a reference image Pf that serves as a reference for inspection of the inspection target area Rx. Specifically, the inspection reference image registration unit 3 registers a variable area reference image Pf1 and a peripheral area reference image Pf2 as reference images Pf.

More specifically, the inspection reference image registration unit 3 is composed of a memory unit and an auxiliary memory unit of the computer CP.

FIG. 4 is an image diagram showing an example of a reference image in an example of an embodiment of the present invention.
FIG. 4A shows an example of a variable domain reference image Pf1, which is one of the reference images Pf.
FIG. 4B shows an example of a surrounding area reference image Pf2, which is one of the reference images Pf.

The variable region reference image Pf1 is a reference for inspection of the variable region Rx1, and the outer edge B1 of the variable region Rx1 is set to a range wider than the standard range Rs in which positional deviation and dimensional error of the outer edge are not permitted. Here, the outer edge B1 of the variable region Rx1 being wider than the standard range Rs does not simply mean that the area is larger, but means that the entire circumference of the outer edge B1 is located outside the standard range Rs.
On the other hand, the surrounding area reference image Pf2 serves as a reference for inspection of the surrounding area Rx2, and the outer edge B2 of the variable area Rx1 is set to a range narrower than the standard range Rs in which positional deviation and dimensional error of the outer edge are not permitted. Here, the outer edge B2 of the variable area Rx1 being narrower than the standard range Rs does not simply mean that the area is narrower, but means that the entire circumference of the outer edge B is located inside the standard range Rs.

The variable area reference image Pf1 and the surrounding area reference image Pf2 are selected in advance as samples that represent the limits of acceptable variation in the outer edge B of the variable area Rx1, and are registered in the inspection reference image registration unit 3.

The edge detection unit 4 processes the inspection image Px to detect the position of the outer edge B of the variable region Rx1 (that is, the boundary with the peripheral region Rx2).
Specifically, the edge detection unit 4 performs difference processing, differentiation processing, etc. on each pixel included in the inspection image Px, and outputs position information of pixels determined to be on the outer edge B of the variable region Rx1.
More specifically, the edge detection unit 4 is composed of a processing unit and an image processing unit of the computer CP, and an execution program.

The inspection unit 5 compares the inspection image Px with the reference image Pf to inspect the inspection target area Rx, and inspects the variable region Rx1 by comparing the variable region Rx1 in the inspection image Px with a region whose position corresponds to the variable region Rx1 in the variable region reference image Pf1 based on the boundary position detected by the edge detection unit 4.

Furthermore, the inspection unit 5 compares the surrounding area Rx2 in the inspection image Px with an area in the surrounding area reference image Pf2 whose position corresponds to the surrounding area Rx2 based on the boundary position detected by the edge detection unit 4, and inspects the surrounding area Rx2.
Specifically, the inspection unit 5 compares the brightness values, etc. of each pixel in the variable region Rx1 in the inspection image Px with the brightness values of pixels in the reference image Pf1 that correspond to the position of the variable region Rx1, and determines whether the brightness difference is within a predetermined range (i.e., within the pass criteria).
More specifically, the inspection unit 5 is composed of a processing unit and an image processing unit of a computer CP, and an execution program.

The wafer holder H holds the wafer W.
Specifically, the wafer holder H supports the wafer W from the lower surface side while maintaining the wafer W in a horizontal state. More specifically, the wafer holder H includes a mounting table H1 having a horizontal upper surface.
The mounting table H1 has grooves and holes in the portion that comes into contact with the wafer W, and these grooves and holes are connected to a negative pressure generating means such as a vacuum pump via a switching valve, etc. The wafer holding part H can hold or release the wafer W by switching these grooves and holes to a negative pressure state or an open-to-air state.

The imaging unit S captures an image of the external appearance of the area to be inspected and outputs image data. Specifically, the imaging unit S includes a lens barrel S0, an illumination unit S1, a half mirror S2, multiple objective lenses S3a and S3b, a revolver mechanism S4, and an imaging camera S5.

The lens barrel S0 fixes the illumination unit S1, half mirror S2, objective lenses S3a and S3b, revolver mechanism S4, imaging camera S5, etc. in a predetermined position and guides illumination light L1 and observation light L2. The lens barrel S0 is attached to the device frame 1f via connecting fittings (not shown) etc.

The illumination unit S1 emits the illumination light L1 required for imaging. Specifically, examples of the illumination unit S1 include a laser diode, a metal halide lamp, a xenon lamp, and an LED light. More specifically, the illumination unit S1 switches on and off based on an external signal control, and emits a strobe light at a specified location or timing.

The half mirror S2 reflects the illumination light L1 emitted from the illumination unit S1 and irradiates it on the wafer W side, and passes the light L2 incident from the wafer W side (also called reflected light or scattered light; in other words, observation light) to the imaging camera S5 side.

The objective lenses S3a and S3b form images of the imaging area on the workpiece W on the imaging element of the imaging camera S5 at different predetermined observation magnifications.

The revolver mechanism S4 switches between the objective lenses S3a and S3b to be used. Specifically, the revolver mechanism S4 rotates and stops at a predetermined angle increments, either manually or based on an external signal control.

The imaging camera S5 captures an imaging area F on the workpiece W and acquires an inspection image Px and a reference image Pf. These acquired images are output to the outside (in this embodiment, a computer CP) as a video signal or video data.

The relative movement unit M moves the wafer holder H and the imaging unit S relative to each other.
Specifically, the relative moving portion M includes an X-axis slider M1, a Y-axis slider M2, and a rotation mechanism M3.

The X-axis slider M1 is attached to the device frame 1f and moves the Y-axis slider M2 in the X direction at any speed and stops it at any position. Specifically, the X-axis slider is composed of a pair of rails extending in the X direction, a slider part that moves on the rails, and a slider drive part that moves and stops the slider part.

The Y-axis slider M2 moves the rotation mechanism M3 in the Y direction at any speed and stops it at any position based on a 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 unit that moves on the rails, and a slider drive unit that moves and stops the slider unit.

The slider drive units for the X-axis slider M1 and the Y-axis slider M2 can be configured with a servo motor that rotates and stops under signal control from the control unit CN, a combination of a pulse motor and a ball screw mechanism, or a linear motor mechanism.

The rotation mechanism M3 rotates the mounting table H1 in the θ direction at any speed and stops it at any angle. Specifically, the rotation mechanism M3 can be, for example, a direct drive motor or the like that rotates/stops it at any angle under signal control from an external device. The mounting table H1 of the wafer holder H is attached to the rotating member of the rotation mechanism M3.

Because the relative movement unit M is configured in this way, while holding the wafer W to be inspected, it can move the wafer W relative to the imaging unit S in the X, Y, and θ directions independently or in combination at a specified speed and angle, or stop the wafer W at any position and angle.

The computer CP receives signals and data from the outside, performs predetermined arithmetic processing and image processing, and outputs signals and data to the outside, and executes the following functions, for example.
Registration, switching, etc. of inspection image registration mode and inspection mode (i.e., operation mode) Registration, switching, etc. of imaging magnification in inspection image registration mode Acquisition, registration, etc. of reference image Pf in inspection image registration mode Registration of inspection recipe (imaging position, imaging order, imaging interval (pitch, interval), movement speed, etc.) in inspection mode, switching of inspection recipe to be used, etc. Image processing of inspection image Px and reference image Pf Position detection (edge detection) of outer edge B of variable region Rx in inspection image Px in inspection mode, acquisition of position information of outer edge B, etc. Comparison of inspection image Px and reference image Pf in inspection mode (i.e., inspection)
More specifically, the computer CP is composed of an input section and an output section, a storage section (called a register or memory), a control section and a calculation section (called a CPU or MPU), an image processing device (called a GPU), an auxiliary storage device (such as a HDD or SSD), etc. (i.e., hardware), and their execution programs, etc. (i.e., software).

The controller CN inputs and outputs signals and data to and from external devices (such as the imaging unit S and the devices of the relative movement unit M, the computer CP, etc.) and performs predetermined control processing, and executes the following functions, for example.
- Outputting a signal to hold/release the wafer W to the wafer holding unit H - Controlling the revolver mechanism S4 to switch the objective lens (imaging magnification) to be used - Outputting a strobe light emission signal to the illumination unit S1 - Outputting an imaging trigger to the imaging camera S5 - Inputting an image (inspection image or reference image) output from the imaging camera S5 - Driving and controlling the relative moving unit M: a function of outputting and controlling a driving signal while monitoring the current positions of the X-axis slider M1, the Y-axis slider M2, and the rotation mechanism M3 In other words, the controller CN can drive and control the relative moving unit M, and output an imaging trigger to the imaging unit S while changing the location of the imaging area F set on the wafer W. Furthermore, it is possible to output an imaging trigger while switching the imaging magnification and the field of view size and changing the imaging interval according to the inspection type, and to acquire a desired image.

The imaging trigger can be output in the following manner, for example.
A method in which the illumination light L1 is emitted for an extremely short period of time (so-called strobe emission) every time a predetermined distance is moved while performing a scan movement in the X direction.
A method in which the object is moved to a predetermined position, stopped there, irradiated with illumination light L1, and an image is captured (so-called step and repeat).

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

<Operation mode and operation flow>
The wafer visual inspection device 1 has an inspection image registration mode and an inspection mode, and can be operated by switching between these modes.

FIG. 5 is a flow diagram of an example of an embodiment of the present invention.
5A shows a series of steps of a flow for capturing and registering an image (i.e., a reference image) that serves as an inspection reference for device chips C arranged on a wafer W using the wafer visual inspection apparatus 1. This is called an inspection image registration flow, and a mode in which the operation is performed according to the below-described operation flow is an inspection image registration mode.

First, the wafer W for registering the reference image Pf is placed on the stage H1 of the wafer visual inspection device 1 (step s1). This wafer W contains device chips C that serve as the standard for determining pass/fail.

Next, the alignment marks formed on the wafer W are read, and the wafer W is aligned (step s2).

Next, the relative movement unit M is controlled to move the wafer W to a position (i.e., the imaging position) where the device chip C to be set as the reference image Pf can be imaged by the imaging unit S (step s3).

Then, the imaging unit S captures a reference image Pf, and the reference image Pf is registered in the inspection reference image registration unit 3 (step s4). Specifically, the reference image Pf for inspecting the variable region Rx1 is registered as the variable region reference image Pf1.

Further, it is determined whether or not a reference image is to be captured and registered (step s5), and if the image is to be captured and registered, the above steps s3 to s5 are repeated.
Specifically, the reference image Pf for inspecting the peripheral region Rx2 is registered as a peripheral region reference image Pf2. On the other hand, if there is no need to further capture and register a reference image, the wafer W is removed (step s6).

Then, it is determined whether or not to capture and register reference images for other wafers (step s7), and if so, steps s1 to s7 are repeated. On the other hand, if there is no need to capture and register reference images, the flow is terminated.

Figure 5 (b) shows a series of steps in a flow for taking an appearance image Px of a device chip C arranged on a wafer W using the wafer appearance inspection device 1 and inspecting the device based on the image. This is called an inspection flow, and the mode in which the device operates according to the operation flow described below is the inspection mode.

First, set a new inspection recipe or select one from pre-registered inspection recipes, and place the wafer W on the placement table H1 (step s11).

Next, the alignment marks formed on the wafer W are read, and the wafer W is aligned (step s12).

Next, the relative movement unit M is controlled to move the wafer W while the imaging unit S captures an image of the device chip C, thereby obtaining an inspection image Px (step s13).

Next, the edge detection unit 4 detects the position of the outer edge B of the variable region Rx1 in the acquired inspection image Px (step s14).

Then, the variable region Rx1 in the inspection image Px is compared with a region in the variable region reference image Pf1 registered in advance, the region corresponding in position to the variable region Rx1, and inspection is performed (step s15). Specifically, the inspection unit 5 compares the variable region Rx1 in the inspection image Px with a region in the variable region reference image Pf1, the region corresponding in position to the variable region Rx1, based on the position of the outer edge B of the variable region Rx1 detected by the edge detection unit 4 in the inspection image Px, to inspect the variable region Rx1.

Furthermore, the peripheral region Rx2 in the inspection image Px is compared with a region in a preregistered peripheral region reference image Pf2 whose position corresponds to that of the peripheral region Rx2, and inspection is performed.
Specifically, the inspection unit 5 inspects the surrounding region Rx2 by comparing the surrounding region Rx2 in the inspection image Px with an area whose position corresponds to that of the surrounding region Rx2 in the surrounding region reference image Pf2 based on the position of the outer edge B of the variable region Rx1 detected by the edge detection unit 4 in the inspection image Px.

Next, it is determined whether or not to acquire another inspection image Px and continue the inspection (step s16), and if the inspection is to be continued, the above-mentioned steps s13 to s16 are repeated.
On the other hand, if there is no need to continue the inspection, the wafer W is removed (step s17).

Then, it is determined whether or not to acquire and inspect inspection images of other wafers (step s18), and if further inspection is to be performed, steps s11 to s18 described above are repeated. On the other hand, if further inspection is not required, the series of steps ends.

Since the wafer visual inspection apparatus 1 according to the present invention has the above-mentioned configuration,
Even if the inspection target portion Rx includes a variable region Rx1 in which positional deviation or dimensional error of the outer edge is permitted, desired inspection results can be obtained without detecting false defects.
[Other forms and modifications]
In the above, an example was given of a configuration in which the inspection unit 5 inspects not only the variable region Rx1 in the inspection image Px, but also the surrounding region Rx2 by comparing it with a region whose position corresponds to the surrounding region Rx2 in the surrounding region reference image Pf2 based on the position of the outer edge B detected by the edge detection unit 4.
However, in order to embody the present invention, inspection of the peripheral region Rx2 is not essential, and a configuration in which inspection is performed only on the variable region Rx1 may also be used.

In the above description, an example has been given in which the inspection target portion Rx is a semiconductor device or the like formed on a wafer W, and an external connection terminal formed on the wafer W in a plating process is set as the variable region Rx1 in the inspection target portion Rx.
In the plating process, the amount of plating deposited is not constant, so the line width and positional accuracy of the wiring circuit pattern vary depending on the amount of deposition. Furthermore, the line width and positional accuracy of the external connection terminals formed in the plating process are not as strict as those of the wiring circuit patterns inside the device, and positional deviation and dimensional accuracy are allowed.
Therefore, if such a portion is set as the inspection target, desired inspection results can be obtained without detecting false defects.
However, the present invention can be applied to the inspection of other inspection target portions in addition to the external connection terminals formed by the plating process.

In the above, an example was given of a configuration in which the inspection target area Rx is set on the surface of the wafer W, but it may also be set on an intermediate layer of stacked substrates (e.g., a bonding surface, etc.). In this case, the imaging unit S may be configured to appropriately select a wavelength that transmits other stacked films or the wafer as illumination light L1, irradiate the inspection target area, and acquire observation light L2 with the imaging camera S5.

In the above description, the wafer visual inspection apparatus 1 is shown, and an example is given of a form in which the inspection image Px is captured (i.e., acquired) while changing the imaging position of the wafer W on which the device chips C to be inspected are arranged in the XY directions.
However, in order to realize the present invention, the relative movement unit M, the imaging unit S, etc. are not essential components, and the inspection image Px transmitted from a host computer or external device in which the inspection image Px is stored is received by the input unit of the computer CP (i.e., acquired by the inspection image acquisition unit 2), the edge detection unit 4 detects the position of the outer edge of the variable region Rx1 contained in the inspection image Px in the same manner as described above, and the inspection unit 5 performs an inspection similar to that described above (so-called offline inspection).

REFERENCE SIGNS LIST 1 Wafer appearance inspection device 2 Inspection image acquisition section 3 Inspection reference image registration section 4 Edge detection section 5 Inspection section H Wafer holder S Imaging section M Relative movement section CP Computer CN Controller RP Recipe registration section 1f Device frame H1 Placement table S0 Tube S1 Illumination section S2 Half mirror S3a, S3b Objective lens S4 Revolver mechanism S5 Imaging camera M1 X-axis slider M2 Y-axis slider M3 Rotation mechanism W Wafer C Device chip (chip component)
F Imaging area (field of view)
Rx: Area to be inspected Rx1: Variable area (area to be inspected)
Rx2 Surrounding area (area to be examined)
Rs Standard range B Outer edge (boundary)
Px: Inspection image Pf1: Variable region reference image Pf2: Peripheral region reference image L1: Illumination light L2: Light incident from the wafer side (reflected light, scattered light)

Claims (3)

An appearance inspection apparatus that captures and inspects the appearance of an inspection target portion,
an inspection image acquisition unit that acquires an appearance image of the inspection target portion as an inspection image; and an inspection reference image registration unit that registers a reference image that serves as a reference for inspection of the inspection target portion.
an inspection unit that compares the inspection image with the reference image to inspect the inspection target area;
The inspection target portion includes a variable region in which positional deviation and dimensional error of an outer edge are allowed,
an edge detection unit that processes the inspection image to detect the position of the outer edge of the variable region;
a variable region reference image serving as a reference for inspection of the variable region is registered as the reference image, the outer edge of the variable region being set in a range wider than a standard range in which positional deviation or dimensional error of the outer edge is not permitted;
a peripheral area reference image serving as a reference for inspection of a peripheral area outside the outer edge of the variable area, the peripheral area reference image being set to a range narrower than the standard range as the reference image;
The inspection unit includes:
Inspecting the variation region by comparing the variation region in the inspection image with a region in the variation region reference image whose position corresponds to the variation region based on the position of the outer edge detected by the edge detection unit; and
An appearance inspection device characterized by inspecting the surrounding area by comparing the surrounding area in the inspection image with an area in the surrounding area reference image whose position corresponds to the surrounding area based on the position of the outer edge of the variable area detected by the edge detection unit.
the inspection target portion is a semiconductor device formed on a wafer,
As the variation region in the test target part,
2. The visual inspection apparatus according to claim 1, wherein said wafer is provided with external connection terminals formed by a plating process.
1. A visual inspection method for inspecting an inspection target part by comparing an inspection image obtained by capturing an appearance of the inspection target part with a reference image, comprising the steps of:
a reference image registration step of registering the reference image in advance;
an inspection image acquisition step of acquiring the inspection image;
an inspection step of comparing the inspection image and the reference image to inspect the inspection target portion,
The inspection target portion includes a variable region in which positional deviation and dimensional error of an outer edge are allowed,
registering a variable region reference image as the reference image, in which the variable region is set to a range wider than a standard range in which positional deviation or dimensional error of the outer edge is not allowed, and which serves as a reference for inspection of the variable region;
an edge detection step of processing the inspection image to detect the location of the outer edge of the variation region;
a step of registering a peripheral area reference image as the reference image, the peripheral area being set to a range narrower than the standard range and serving as a reference for inspection of a peripheral area outside the outer edge of the variable area;
In the inspection step, the variation region in the inspection image is compared with a region in the variation region reference image, the region corresponding in position to the variation region, based on the position of the outer edge detected in the edge detection step, to inspect the variation region, and further
An appearance inspection method comprising: comparing the surrounding area in the inspection image with an area in the surrounding area reference image whose position corresponds to that of the surrounding area based on the position of the outer edge of the variable area detected in the edge detection step, thereby inspecting the surrounding area.

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