Appearance inspection device and method

Abstract

To provide exterior appearance inspection device and method that can obtain a desired inspection result without detecting a pseudo defect even if a variation area having a position displacement of an outer edge or dimension error thereof allowed is included in an inspection object portion.SOLUTION: An exterior appearance inspection device, which inspects an exterior appearance of an inspection object portion, comprises: an inspection image acquisition unit 2 that acquires an inspection image Px; an inspection reference image registration unit 3 that registers a reference image serving as a reference of an inspection; an inspection unit 5 that performs an inspection in comparison of the inspection image with the reference image, in which, in the inspection object portion, a variation area is included that has a position displacement of an outer edge or dimension error thereof allowed; and an edge detection unit 4 that detects an outer edge position of the variation area, in which as the reference image, a variation area reference image Pf1 is registered that becomes the reference of the inspection with respect to the variation area. The inspection unit is configured to inspect the variation area by comparing the variation area in the inspection image with an area to which the variation area and a position in the variation area reference image correspond based on the outer edge position detected by the edge detection unit.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an appearance inspection apparatus and method for inspecting an inspection target portion by comparing an inspection image of the inspection target portion with a reference image, and more particularly to a wafer appearance inspection apparatus and method for imaging the appearance of semiconductor devices formed on a wafer and determining the quality of the semiconductor devices. [Background technology]

[0002] Semiconductor devices are formed by forming a large number of semiconductor device circuits (i.e. the repeating external pattern of device chips) on top of each other in layers on a semiconductor wafer, which is then singulated into individual chip components. The chip components are then packaged and shipped as individual electronic components or incorporated into electrical products.

[0003] 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).

[0004] Also, a technique is known in which defects are detected after an inspection object image and a reference image are aligned, thereby reducing false detections due to alignment errors (eg, Patent Document 2).

[0005] Meanwhile, a technique is known in which an inspection image and a reference image are subjected to subtraction processing (that is, comparison) to mask and eliminate noise generated due to deviations in pattern matching at image boundaries (eg, Patent Document 3). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2007-155610 A [Patent Document 2] JP 2003-4427 A [Patent Document 3] JP 2000-335062 A Summary of the Invention [Problem to be solved by the invention]

[0007] 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.

[0008] Because this wiring circuit pattern is deeply related to the performance of the device chip, strict inspection is required for breaks, shorts, differences in line width, and the inclusion of foreign matter.

[0009] On the other hand, since the external connection terminals only need to be able to bond and conduct with external devices, lead wires, etc., there is no requirement for strictness with respect to positional deviation or dimensional errors of the outer edges as compared to the wiring circuit pattern.

[0010] Therefore, when an inspection image of an inspection target portion contains an area (variable area) where positional deviation or dimensional error of the outer edge is allowed, the position of the boundary (i.e., outer edge) with the surrounding area (peripheral area) varies for each inspection image. When this happens, when comparing with a reference image, the area where the position of the outer edge varies in the inspection image is detected as a defect (so-called pseudo defect), which is a factor in reducing the yield rate of device chips.

[0011] Furthermore, the conventional techniques such as those disclosed in Patent Documents 2 and 3 are based on the premise that the size, range, pattern, etc. of the reference image are constant, and are not able to deal with cases in which the dimensions of the inspection target area vary.

[0012] 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. [Means for solving the problem]

[0013] 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 part as an inspection image; 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; As a reference image, Outer edge a reference image of a variable region serving as a reference for inspection of the variable region is registered, the reference image being an inspection reference for the variable region, the reference image being a reference for inspection of ... 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.

[0014] 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. As a reference image, Outer edge a step of registering a variation area reference image serving as a reference for inspection of the variation area, the variation area being set to a range wider than a standard range in which positional deviation and dimensional error are not permitted; 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 position of which corresponds to that of the variation region, based on the position of the outer edge detected in the edge detection step, 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 in the edge detection step, and the surrounding area is inspected. Effect of the Invention

[0015] Even if the inspection target portion includes a variable region in which positional deviation or dimensional error of the outer edge is permitted, the desired inspection result can be obtained without detecting false defects. [Brief description of the drawings]

[0016] [Figure 1] FIG. 2 is an image diagram showing an example of an inspection image in an example of an embodiment of the present invention. [Diagram 2] 1 is a schematic diagram showing an overall configuration of an example of an embodiment of the present invention; [Diagram 3] FIG. 1 is a conceptual diagram showing how an exterior image is captured in an example of an embodiment of the present invention. [Figure 4]FIG. 2 is an image diagram showing an example of a reference image in an example of an embodiment of the present invention. [Diagram 5] FIG. 1 is a flow diagram of an example of an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the following description, the three axes of an orthogonal coordinate system are designated as X, Y, and Z, the horizontal direction is designated as the X direction and the Y direction, and the direction perpendicular to the XY plane (i.e., the direction of gravity) is designated as the Z direction. In addition, the direction against gravity in the Z direction is designated as up, and the direction in which gravity acts is designated as down. In addition, the direction of rotation around the Z direction as the central axis is designated as the θ direction.

[0018] 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 surrounding region Rx2 adjacent to the variable region Rx1.

[0019] 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 portion Rx, and a wiring circuit pattern, etc. is set as a peripheral region Rx2 in the inspection target portion Rx.

[0020] Fig. 2 is a schematic diagram showing the overall configuration of an example of an embodiment of the present invention, in which each part constituting a wafer visual inspection apparatus 1 according to the present invention is shown.

[0021] The wafer visual inspection device 1 inspects the appearance of an inspection target portion Rx set on the surface of a wafer W by imaging it. For example, it is configured to acquire an inspection image Px while sequentially imaging 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 compare it with a reference image Pf registered in advance, thereby continuously inspecting the entire surface of the wafer W. 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.

[0022] More specifically, the wafer visual inspection apparatus 1 includes a wafer holder H, an imaging unit S, a relative moving unit M, a computer CP, a controller CN, and the like.

[0023] The inspection image acquisition unit 2 acquires an appearance image of an inspection target region 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.

[0024] Fig. 3 is a conceptual diagram showing how to capture an external image in one example of a form embodying the present invention. Fig. 3 shows how an imaging camera S5 of an imaging unit S sequentially captures the external images of device chips C formed on a wafer W at a predetermined pitch in the XY directions while moving relatively to the wafer W in the direction indicated by an arrow Vs.

[0025] Specifically, during the relative movement of the relative moving unit M (for example, movement in the direction of the arrow Vs), the illumination unit S1 emits a strobe light at predefined intervals or positions, and the imaging camera S5 captures an external image similar to a still image. Then, the external image output from the imaging camera S5 is input as an inspection image Px to the input unit of the computer CP (i.e., the inspection image Px is acquired).

[0026] The inspection reference image registration unit 3 registers a reference image Pf that serves as a reference for inspection of the inspection target region Rx. Specifically, the inspection reference image registration unit 3 registers a variable region reference image Pf1 and a surrounding region reference image Pf2 as the reference image Pf.

[0027] More specifically, the inspection reference image registration unit 3 is composed of a storage unit and an auxiliary storage unit of the computer CP.

[0028] FIG. 4 is an image diagram showing an example of a reference image in an example of an embodiment of the present invention. FIG. 4(a) shows an example of a variable region reference image Pf1, which is one of the reference images Pf. FIG. 4(b) shows an example of a surrounding area reference image Pf2, which is one of the reference images Pf.

[0029] The variable region reference image Pf1 is a reference for inspection of the variable region Rx1. The outer edge B1 of the variable region Rx1 is Outer edge The outer edge B1 of the variable region Rx1 is set to a range wider than the standard range Rs, which does not allow for positional deviation or dimensional error. Here, the range in which the outer edge B1 of the variable region Rx1 is wider than the standard range Rs does not simply mean that the area is wider, but 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 is a reference for inspection of the surrounding area Rx2, and the outer edge B2 of the variable area Rx1 is Outer edge The range in which the outer edge B2 of the variable region Rx1 is narrower than the standard range Rs, in which positional deviation and dimensional error are not permitted. Here, the range in which the outer edge B2 of the variable region Rx1 is narrower than the standard range Rs does not simply mean that the area is narrower, but that the entire circumference of the outer edge B is located inside the standard range Rs.

[0030] The variable region reference image Pf1 and the surrounding region reference image Pf2 are selected in advance as limit samples within which the variation of the outer edge B of the variable region Rx1 is allowed, and are registered in the inspection reference image registration unit 3.

[0031] 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 surrounding region Rx2). Specifically, the edge detection unit 4 performs difference processing, differentiation processing, and the like 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.

[0032] 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 area Rx1 by comparing the variable area Rx1 in the inspection image Px with an area whose position corresponds to the variable area Rx1 in the variable area reference image Pf1 based on the boundary position detected by the edge detection unit 4.

[0033] 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 the computer CP, and an execution program.

[0034] 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.

[0035] The imaging unit S captures an image of the exterior of a target area 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.

[0036] The lens barrel S0 fixes the illumination unit S1, the half mirror S2, the objective lenses S3a and S3b, the revolver mechanism S4, the imaging camera S5, etc. in a predetermined position, and guides the illumination light L1 and the observation light L2. The lens barrel S0 is attached to the device frame 1f via a connecting fitting or the like (not shown).

[0037] The illumination unit S1 emits 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 the light and emits a strobe light at a predetermined location or timing based on an external signal control.

[0038] The half mirror S2 reflects the illumination light L1 emitted from the illumination section S1 and irradiates it onto the wafer W side, and passes the light (also called reflected light or scattered light; i.e., observation light) L2 incident from the wafer W side to the imaging camera S5 side.

[0039] The objective lenses S3a and S3b form images of the imaging areas on the workpiece W on the imaging element of the imaging camera S5 at different predetermined observation magnifications.

[0040] 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 in increments, manually or based on an external signal control.

[0041] 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 (to a computer CP in this embodiment) as a video signal or video data.

[0042] The relative movement unit M moves the wafer holder H and the imaging unit S relative to each other. Specifically, the relative moving section M includes an X-axis slider M1, a Y-axis slider M2, and a rotation mechanism M3.

[0043] 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.

[0044] The Y-axis slider M2 moves the rotation mechanism M3 in the Y direction at a desired speed and stops it at a desired 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.

[0045] 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.

[0046] The rotation mechanism M3 rotates the mounting table H1 in the θ direction at a desired speed and stops it at a desired angle. Specifically, the rotation mechanism M3 may be, for example, a direct drive motor or the like that rotates / stops it at a desired 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.

[0047] Because the relative movement unit M is configured as described above, while holding the wafer W to be inspected, the wafer W can be moved relatively to the imaging unit S in the X, Y and θ directions at a predetermined speed and angle, either independently or in combination, or stopped at any position and angle.

[0048] 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 and switching of inspection image registration mode and inspection mode (i.e., operation mode) - Registration and switching of imaging magnification in inspection image registration mode - Acquisition and registration of reference image Pf in inspection image registration mode -Registering inspection recipes in inspection mode (imaging positions, imaging order, imaging intervals (pitch, interval), movement speed, etc.), switching inspection recipes to be used, etc. Image processing for inspection images Px and reference images Pf -Detection of the position (edge ​​detection) of the outer edge B of the variable area Rx in the inspection image Px in inspection mode, acquisition of the position information of the outer edge B, etc. Comparison of the inspection image Px with the 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).

[0049] 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, and the computer CP) and performs predetermined control processing, and for example, executes the following functions. Outputs a signal to the wafer holder H to hold / release the wafer W. Control the revolver mechanism S4 to switch the objective lens (imaging magnification) to be used -Strobe light signal output to lighting unit S1 - Outputs an imaging trigger to the imaging camera S5 Input the image (inspection image or reference image) output from the imaging camera S5 Drive control of relative movement unit M: A function that monitors the current positions of the X-axis slider M1, Y-axis slider M2, and rotation mechanism M3, while outputting drive signals and controlling them. That is, the controller CN can drive and control the relative moving unit M, and can output an imaging trigger to the imaging unit S while changing the location of the imaging area F set on the wafer W. Furthermore, the controller CN can switch the imaging magnification and the field of view size according to the inspection type, and output an imaging trigger while changing the imaging interval, so that a desired image can be acquired.

[0050] The imaging trigger can be output in the following manner, for example. A method in which the illumination light L1 is emitted for a very short period of time (so-called strobe emission) every time a certain distance is moved while scanning in the X direction. A method in which the object is moved to a predetermined position, stopped, illuminated with illumination light L1, and then captured (so-called step and repeat).

[0051] 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).

[0052] <Operation mode and operation flow> The wafer visual inspection apparatus 1 has an inspection image registration mode and an inspection mode, and can be operated by switching between these modes.

[0053] FIG. 5 is a flow diagram of an example of an embodiment of the present invention. 5(a) shows a series of steps 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 the mode in which the apparatus operates according to the operation flow described below is the inspection image registration mode.

[0054] First, a wafer W for registering a reference image Pf is placed on a placement table H1 of the wafer visual inspection apparatus 1 (step s1). This wafer W includes device chips C that serve as a reference for determining whether the wafer is good or bad.

[0055] Subsequently, the alignment marks formed on the wafer W are read, and the wafer W is aligned (step s2).

[0056] Next, the relative moving unit M is controlled to move the wafer W to a position (that is, an imaging position) where the imaging unit S can image the device chip C set as the reference image Pf (step s3).

[0057] Next, 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 a variable region reference image Pf1.

[0058] Furthermore, 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-mentioned 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).

[0059] Then, it is determined whether or not to capture and register reference images for other wafers (step s7), and if so, the above steps s1 to s7 are repeated. On the other hand, if there is no need to capture and register reference images, the series of flows is terminated.

[0060] 5(b) shows a series of steps of a flow for taking an appearance image Px of a device chip C arranged on a wafer W using the wafer appearance inspection apparatus 1 and inspecting based on the image. This is called an inspection flow, and a mode for operating according to the operation flow described below is the inspection mode.

[0061] First, an inspection recipe is set by new registration or selected from pre-registered inspection recipes, and the wafer W is placed on the placement table H1 (step s11).

[0062] Subsequently, the alignment mark formed on the wafer W is read, and the wafer W is aligned (step s12).

[0063] Next, the relative moving 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).

[0064] Next, the position of the outer edge B of the variable region Rx1 in the acquired inspection image Px is detected by the edge detection unit 4 (step s14).

[0065] Next, 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 position of which corresponds to that of 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 position of which corresponds to that of 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.

[0066] Furthermore, the surrounding area Rx2 in the inspection image Px is compared with an area in a preregistered surrounding area reference image Pf2, the area corresponding in position to the surrounding area Rx2, for inspection. Specifically, the inspection unit 5 inspects the surrounding area Rx2 by comparing the surrounding area Rx2 in the inspection image Px with an area whose position corresponds to that of the surrounding area Rx2 in the surrounding area reference image Pf2 based on the position of the outer edge B of the variable area Rx1 detected by the edge detection unit 4 in the inspection image Px.

[0067] Next, it is determined whether or not to acquire another examination image Px and continue the examination (step s16), and if the examination 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).

[0068] 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, the above steps s11 to s18 are repeated. On the other hand, if further inspection is not required, the series of flows is terminated.

[0069] Since the wafer visual inspection apparatus 1 according to the present invention has the above-mentioned configuration, Even if the inspection target region 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 variations] 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 in the surrounding region reference image Pf2 whose position corresponds to the surrounding region Rx2 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 be used.

[0070] 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.

[0071] In the above, the inspection target portion Rx is set on the surface of the wafer W, but it may 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 portion with the light, and acquire observation light L2 with the imaging camera S5.

[0072] 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 (ie, 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 an 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 as described above, and the inspection unit 5 performs an inspection similar to that described above (so-called offline inspection). [Explanation of symbols]

[0073] 1. Wafer visual inspection equipment 2. Inspection image acquisition section 3. Inspection reference image registration section 4 Edge detection section 5. Inspection Department H Wafer holder S Imaging unit M Relative movement part CP Computer CN Controller RP Recipe Registration 1f Equipment frame H1 Mounting stand S0 Telescope S1 Lighting section S2 Half Mirror S3a, S3b Objective Lenses S4 Nosepiece Mechanism S5 Imaging Camera M1 X-axis slider M2 Y-axis slider M3 Rotation Mechanism W wafer C Device chip (chip part) F Imaging area (field of view) Rx Test area Rx1 Variable area (area to be examined) Rx2 Surrounding area (area to be examined) Rs Standard Range B Outer edge (boundary) Px Inspection Image Pf1 Variation region reference image Pf2 Surrounding area reference image L1 illumination light L2 Light incident from the wafer side (reflected light, scattered light)

Claims

1. 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 part as an inspection image; 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 The peripheral area in the inspection image is compared with an area in the peripheral area reference image, the area being located corresponding to the peripheral area based on the position of the outer edge of the fluctuation area detected by the edge detection unit, to inspect the peripheral area. A visual inspection apparatus comprising:

2. the inspection target portion is a semiconductor device formed on a wafer, As the variation region in the test target part, The wafer is provided with external connection terminals formed by a plating process.

2. The visual inspection apparatus according to claim 1 .

3. 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 permitted, 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 The peripheral region in the inspection image is compared with a region in the peripheral region reference image, the position of which corresponds to the peripheral region based on the position of the outer edge of the fluctuation region detected in the edge detection step, to inspect the peripheral region. A visual inspection method comprising:

Images