Inspection device and inspection method

Abstract

To provide technology that makes it possible to detect at high speed an abnormality in a wire including a wire-bonded part.SOLUTION: An inspection device 100 comprises: an imaging device 105 located upward of an aluminum wire 1, for capturing an image of the aluminum wire 1 in order to acquire the two-dimensional position information of the aluminum wire 1; a coaxial illumination 103 located coaxially with the imaging device 105, for irradiating the aluminum wire 1 with coaxial illumination light; and a control device 301 for acquiring, from the image, the two-dimensional position information of a region where a vertex 3 of the aluminum wire 1 exists and the luminance of which is brighter than the surrounding and a region where a wire-bonded part 2 of the aluminum wire 1 exists and the luminance of which is brighter than the surrounding.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to an inspection apparatus and an inspection method.

Background Art

[0002] Conventionally, techniques for inspecting abnormalities in wire bonding formed as wiring between electrodes have been widely proposed.

[0003] For example, Patent Document 1 discloses a method of applying coaxial illumination from above a wire, imaging the wire while moving an imaging device arranged above the wire in the height direction, and measuring the height position of the wire from the brightness distribution of the bright spots at the apex of the imaged wire.

[0004] Further, for example, Patent Document 2 discloses a method of applying coaxial illumination from above a wire, calculating the two-dimensional coordinates of the apex by detecting the bright spots at the apex of the wire, and measuring the height with a laser displacement meter at the calculated position.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the method described in Patent Document 1, although the height position of the apex of the wire can be measured, abnormalities in the wire bonding portion, which is the joint portion of the wire, cannot be detected. Further, even when measuring the height position of the apex of the wire, it is necessary to capture a large number of images while moving the imaging device in the height direction to measure one wire, and there is a problem that the measurement time becomes extremely long when inspecting a plurality of wires.

[0007] Similarly, in the method described in Patent Document 2, although the height position of the apex portion of the wire can be measured, an abnormality in the wire bonding portion, which is the joining portion of the wires, cannot be detected.

[0008] Therefore, an object of the present disclosure is to provide a technique capable of quickly detecting an abnormality in a wire including a wire bonding portion.

Means for Solving the Problems

[0009] An inspection apparatus according to the present disclosure is an inspection apparatus for detecting an abnormality in a work to be inspected in which both ends are wire-bonded to a portion to be joined of a semiconductor device by a wedge bonding method. The work to be inspected is a wire having a diameter of 100 μm or more, and is disposed above the wire. An imaging device that images an image of the wire to acquire two-dimensional position information of the wire, a coaxial illumination that is disposed coaxially with the imaging device and irradiates coaxial illumination light onto the wire, and a control device that acquires two-dimensional position information of a region having a higher luminance than the surrounding area existing at the apex portion of the wire and a region having a higher luminance than the surrounding area existing at the wire bonding portion, which is the joining portion of the wire, from the image.

Effects of the Invention

[0010] According to the present disclosure, since the inspection apparatus can acquire two-dimensional position information of the apex portion and the wire bonding portion of the wire by a single imaging, it is possible to quickly detect an abnormality in the wire including the wire bonding portion by using the two-dimensional position information.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

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Figure 10

Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0012] <Embodiment 1> Embodiment 1 will be described below with reference to the drawings. FIG. 1 is a side view of an inspection apparatus 100 according to Embodiment 1. FIG. 2 is a side view showing a joined state between an aluminum wire 1 and a wire connection terminal portion 4 and an electrode 6 in Embodiment 1.

[0013] In FIG. 1, the X direction, Y direction, and Z direction are orthogonal to each other. The X direction, Y direction, and Z direction shown in the following figures are also orthogonal to each other. Hereinafter, the direction including the X direction and the -X direction which is the opposite direction of the X direction is also referred to as the "X-axis direction". Further, hereinafter, the direction including the Y direction and the -Y direction which is the opposite direction of the Y direction is also referred to as the "Y-axis direction". Further, hereinafter, the direction including the Z direction and the -Z direction which is the opposite direction of the Z direction is also referred to as the "Z-axis direction".

[0014] As shown in FIG. 1, the inspection apparatus 100 detects an abnormality of a work to be inspected in which both ends are wire-bonded to the bonding portions of the semiconductor device 10 by the wedge bonding method. The inspection apparatus 100 includes an inspection stage 201, a motor 202, a ball screw 203, an imaging device 105, a coaxial illumination 103, and a control device 301.

[0015] On the upper surface (the surface in the Z direction) of the inspection stage 201, a semiconductor device 10 including an aluminum wire 1 (corresponding to a wire) which is a work to be inspected is placed. Note that only a part of the semiconductor device 10 is shown in FIG. 1. The inspection stage 201 is connected to the motor 202 and the ball screw 203, and is movable in the X-axis direction by driving the motor 202. Although not shown, the inspection stage 201 is also connected to a motor and a ball screw for Y-axis driving, and is movable in the Y-axis direction by driving the motor for Y-axis driving. Here, the inspection stage 201, the motor 202, and the ball screw 203 correspond to a moving mechanism that moves the semiconductor device 10 in two-dimensional directions (the X-axis direction and the Y-axis direction).

[0016] Next, the semiconductor device 10 will be described. As shown in FIGS. 1 and 2, the semiconductor device 10 includes a substrate 5, an electrode 6, a semiconductor chip 7, and an aluminum wire 1 having a diameter of 100 μm or more. The semiconductor chip 7 is mounted on the upper surface (the surface in the Z direction) of the substrate 5 via solder 50. One end of the aluminum wire 1 is wire-bonded to the wire connection terminal portion 4 (in the Z direction) formed on the semiconductor chip 7 by the wedge bonding method. The other end of the aluminum wire 1 is wire-bonded to the electrode 6 (in the Z direction) by the wedge bonding method.

[0017] Here, the substrate 5 may be a metal substrate mainly made of copper or aluminum, etc., or may be a substrate in which a metal plate is bonded to one or both sides of an insulator substrate. Similarly, the electrode 6 may also be a metal substrate mainly made of copper or aluminum, etc., or may be a substrate in which a metal plate is bonded to one or both sides of an insulator substrate.

[0018] In the wedge bonding method, the aluminum wire 1 has a wire bonding portion 2 which is a bonding location with the bonded portion of the semiconductor device 10, and a vertex portion 3 which is the vertex in the Z direction. The bonded portion of the semiconductor device 10 is the wire connection terminal portion 4 of the semiconductor chip 7 or the electrode 6.

[0019] Returning to the description of the inspection device 100. As shown in FIG. 1, the imaging device 105 is disposed above (in the Z direction) the aluminum wire 1. The imaging device 105 has an optical lens 104 that forms an image of the semiconductor device 10 including the aluminum wire 1, and captures the image formed by the optical lens 104 to obtain the two-dimensional position information of the aluminum wire 1. Here, the two-dimensional position information is the position information of two-dimensional coordinates (XY coordinates).

[0020] The coaxial illumination 103 is disposed between the aluminum wire 1 and the imaging device 105 and coaxially with the imaging device 105. The coaxial illumination 103 has a half mirror 102 and an illumination light source 101, and uses the half mirror 102 and the illumination light source 101 to vertically irradiate the semiconductor device 10 including the aluminum wire 1 with coaxial illumination light from above (in the Z direction).

[0021] The control device 301 acquires the image captured by the imaging device 105 and performs appropriate arithmetic processing. More specifically, the control device 301 performs arithmetic processing to obtain two-dimensional position information of regions where the luminance is brighter than the surroundings existing at the apex portion 3 of the aluminum wire 1 and regions where the luminance is brighter than the surroundings existing at the wire bonding portion 2 which is the bonding location of the aluminum wire 1 from the image. Further, the control device 301 controls each part of the inspection device 100. Note that the inspection device 100 may include a control device that controls each part of the inspection device 100 separately from the control device 301.

[0022] The control device 301 includes a processor (not shown) and a memory (not shown). The above functions of the control device 301 are described in a program, and the functions of the control device 301 are realized when the processor executes the program.

[0023] As shown in FIG. 1, when wire bonding is performed by the wedge bonding method using an aluminum wire 1 having a diameter of 100 μm or more, ultrasonic bonding is performed while pressing from above (in the Z direction) with the aluminum wire 1 laid down. Therefore, a flat region exists on the surface (the surface in the Z direction) of the wire bonding portion 2.

[0024] When the coaxial illumination light (hereinafter also simply referred to as "illumination light") irradiated by the coaxial illumination 103 hits the aluminum wire 1, since there are portions perpendicular to the irradiation direction of the illumination light on the surfaces (surfaces in the Z direction) of the vertex portion 3 and the wire bonding portion 2, they are reflected in the direction opposite to the irradiation direction, that is, in the direction of the imaging device 105. Therefore, when the aluminum wire 1 is imaged by the imaging device 105, the entire aluminum wire 1 becomes dark in luminance, and the vertex portion 3 and the wire bonding portion 2 are observed as regions with higher luminance than the surroundings within the dark region.

[0025] On the other hand, when wire bonding is performed using an aluminum wire 1 with a diameter of less than 100 μm, since there are more deformed portions on the surface (surface in the Z direction) of the aluminum wire 1, the regions perpendicular to the irradiation direction of the light decrease, and accordingly, the regions with bright luminance become narrower. Therefore, it becomes difficult to detect the wire bonding portion 2 by an image. From this, it is desirable that the diameter of the aluminum wire 1 be 100 μm or more.

[0026] FIG. 3 is a diagram showing an image obtained by imaging the semiconductor device 10 from above (Z direction) by the imaging device 105 included in the inspection apparatus 100 according to the first embodiment.

[0027] As shown in FIG. 3, two aluminum wires 1a and 1b are arranged on the upper surface (surface in the Z direction) of the substrate 5. The aluminum wire 1a has wire bonding portions 2a wire-bonded at both ends by the wedge bonding method, and both ends of the aluminum wire 1a are joined to the wire connection terminal portion 4a and the electrode 6a, respectively.

[0028] Similarly to the aluminum wire 1a, the aluminum wire 1b has wire bonding portions 2b wire-bonded at both ends by the wedge bonding method, and both ends of the aluminum wire 1b are joined to the wire connection terminal portion 4b and the electrode 6b, respectively. After wire bonding of the aluminum wire 1b, the loop portion of the aluminum wire 1b has fallen due to an external force.

[0029] Since the coaxial illumination 103 irradiates the illumination light vertically from directly above the aluminum wires 1a and 1b in the Z direction, the apex portions 3 and the wire bonding portions 2 of the two aluminum wires 1a and 1b are observed as bright regions in the captured image. On the other hand, since there are almost no horizontal regions in the entire aluminum wires 1a and 1b, regions other than the apex portions 3 and the wire bonding portions 2 are observed as dark regions as a whole.

[0030] Normally, when connecting between two points with an aluminum wire, the aluminum wire has a linear shape like the aluminum wire 1a, and the wire bonding portion 2 and the apex portion 3 are in a positional relationship where they are aligned in a straight line. On the other hand, when an external force is applied and the loop portion is collapsed like the aluminum wire 1b, the wire bonding portion 2 and the apex portion 3 are not aligned in a straight line, and the position of the apex portion 3 is shifted with respect to the straight line connecting the two wire bonding portions 2.

[0031] Figure 4 is a view taken along arrow A in Figure 3. Here, for the sake of clarity of explanation, the illustration of the electrodes 6a and 6b is omitted.

[0032] As shown in Figure 4, a vertical loop is formed from the wire bonding portion 2 to the apex portion 3 of the aluminum wire 1a, whereas the aluminum wire 1b is formed obliquely from the wire bonding portion 2 to the apex portion 3, that is, it can be seen that the loop is in a shape where it is collapsed obliquely.

[0033] Also, when the aluminum wire is collapsed obliquely, as shown in Figures 3 and 4, the distance between the apex portion 3 of the aluminum wire 1a and the apex portion 3 of the aluminum wire 1b becomes closer. Therefore, by measuring the two-dimensional distance of the bright regions existing at the apex portion 3 of the aluminum wire 1a and the apex portion 3 of the aluminum wire 1b, the proximity between the aluminum wire 1a and the aluminum wire 1b can be detected. Since it can be inspected from a wide-range image captured by the imaging device 105, a plurality of aluminum wires 1a and 1b can be inspected collectively in a short time.

[0034] Next, the inspection method according to Embodiment 1 will be described. FIG. 5 is a flowchart of the inspection method according to Embodiment 1.

[0035] As shown in FIG. 5, first, the control device 301 positions the inspection stage 201 at a determined position (step S1), and images the aluminum wire 1 with the imaging device 105 (step S2). The control device 301 acquires two-dimensional position information of the bright regions existing in the wire bonding portion 2 and the bright regions existing in the vertex portion 3 from the image captured by the imaging device 105 (step S3).

[0036] Next, the control device 301 compares the acquired two-dimensional position information with the two-dimensional position information preset in the memory of the control device 301, and determines that there is an abnormality in wire deformation or bonding position when there is a difference of a certain level or more (step S4).

[0037] Here, the determination method regarding the abnormality in wire deformation or bonding position will be described in detail. The control device 301 calculates the centroid of the bright region existing in the wire bonding portion 2 and the centroid of the bright region existing in the vertex portion 3 from the acquired image, and calculates the two-dimensional distance between the two centroids. The control device 301 compares the obtained two-dimensional distance with the two-dimensional distance between the wire bonding portion 2 and the vertex portion 3 preset in the memory of the control device 301, and determines that there is an abnormality in wire deformation or bonding position when there is a difference of a certain level or more.

[0038] Alternatively, the bright regions existing in the wire bonding portion 2 and the vertex portion 3 may be surrounded by rectangles with the minimum area, the centers of the rectangles may be set as the wire bonding portion 2 and the vertex portion 3 respectively, and the two-dimensional distance between the two may be compared with the two-dimensional distance between the wire bonding portion 2 and the vertex portion 3 preset in the memory of the control device 301.

[0039] Alternatively, the distance between the closest pixels of the bright regions existing in the wire bonding portion 2 and the vertex portion 3 may be compared with the two-dimensional distance of the wire bonding portion 2 and the vertex portion 3 preset in the memory of the control device 301.

[0040] As described above, the inspection device 100 according to the first embodiment is disposed above the aluminum wire 1 (in the Z direction), and includes an imaging device 105 that images the aluminum wire 1 to acquire two-dimensional position information of the aluminum wire 1, a coaxial illumination 103 that is disposed coaxially with the imaging device 105 and irradiates the aluminum wire 1 with coaxial illumination light, and a control device 301 that acquires two-dimensional position information of a region that is brighter than the surroundings existing in the vertex portion 3 of the aluminum wire 1 and a region that is brighter than the surroundings existing in the wire bonding portion 2 that is the joint portion of the aluminum wire 1.

[0041] Specifically, the control device 301 compares the two-dimensional position information of the region that is brighter than the surroundings existing in the acquired vertex portion 3 and the region that is brighter than the surroundings existing in the wire bonding portion 2 with the two-dimensional position information of the preset vertex portion 3 and wire bonding portion 2, and determines that there is an abnormality in the wire deformation or the bonding position when there is a difference of a certain level or more.

[0042] Therefore, since the inspection device 100 can acquire the two-dimensional position information of the vertex portion 3 and the wire bonding portion 2 of the aluminum wire 1 by a single imaging, it is possible to quickly detect an abnormality of the aluminum wire 1 including the wire bonding portion 2 using the two-dimensional position information.

[0043] Further, as shown in FIGS. 3 and 4, the control device 301 acquires two-dimensional position information of an area that is brighter in luminance than the periphery existing at the vertex portions 3 of the plurality of aluminum wires 1a and 1b from the image, measures the distances between the plurality of vertex portions 3 of the plurality of aluminum wires 1a and 1b from the acquired two-dimensional position information, and compares the measured distances between the vertex portions 3 with the preset distances between the plurality of vertex portions 3, thereby detecting the proximity between the aluminum wire 1a and the aluminum wire 1b. Thereby, the possibility of contact between the adjacent aluminum wires 1a and 1b can be detected. Further, when inspecting a plurality of aluminum wires 1a and 1b, since the inspection can be performed from a wide-range image captured by the imaging device 105, the plurality of aluminum wires 1a and 1b can be inspected collectively and in a short time.

[0044] <Modification Example of Embodiment 1> The aluminum wire 1 may be a thin metal wire made of copper, gold, silver, etc. as the main material in addition to aluminum, and can be wire-bonded by the wedge bonding method.

[0045] Further, although the position for capturing an image is determined by the inspection stage 201 moving in the two-dimensional direction, the imaging device 105 and the coaxial illumination 103 may be configured to move in the two-dimensional direction, and the position for capturing an image may be determined by the imaging device 105 and the coaxial illumination 103 moving in the two-dimensional direction.

[0046] Further, although the inspection stage 201 is configured to be movable by the motor 202 and the ball screw 203, a configuration using a linear motor may be employed.

[0047] Further, the inspection stage 201 may have a structure that moves in the height direction (Z-axis direction) to adjust the focus of the imaging device 105, or the imaging device 105 may have a structure that moves in the height direction (Z-axis direction).

[0048] One end of the aluminum wire 1 is joined to the wire connection terminal portion 4 on the semiconductor chip 7 (in the Z direction), and the other end is joined to the electrode 6. However, the joined portion of the semiconductor device 10 is not limited to this, and any material that can be wire-bonded by the wedge bonding method may be used.

[0049] <Embodiment 2> Next, the inspection apparatus 100 according to Embodiment 2 will be described. FIG. 6 is a side view of the inspection apparatus 100 according to Embodiment 2. In Embodiment 2, the same components as those described in Embodiment 1 are denoted by the same reference numerals, and the description thereof is omitted.

[0050] In Embodiment 2, in addition to the configuration of Embodiment 1, the inspection apparatus 100 further includes a laser displacement meter 302 as shown in FIG. 6. The laser displacement meter 302 is disposed above the aluminum wire 1 (in the Z direction).

[0051] The control device 301 (see FIG. 1) moves the inspection stage 201 in the two-dimensional direction with respect to the detected position of the two-dimensional coordinates of the wire bonding portion 2, so that the wire bonding portion 2 is positioned so as to exactly hit the laser 303 irradiated by the laser displacement meter 302. Information on the height position of the wire bonding portion 2 is obtained by this operation. In FIG. 6, the laser displacement meter 302 measures the position of the wire bonding portion 2 on the wire connection terminal portion 4 (in the Z direction), but the position of the wire bonding portion 2 on the electrode 6 (in the Z direction) can also be measured in the same manner.

[0052] FIG. 7 is a side view showing a state in which the aluminum wire 1 is floating in the inspection apparatus 100 according to Embodiment 2. As shown in FIG. 7, one end side (-X side) of the wire bonding portion 2 of the aluminum wire 1 is slightly floating from the wire connection terminal portion 4. The floating amount is, for example, about 10 μm or more and several tens of μm. In such a state, it is difficult to determine whether the wire bonding portion 2 is floating only by observing from above (in the Z direction).

[0053] As a cause of such a state, when wire bonding is performed with the surface (the surface in the Z direction) of the wire connection terminal portion 4 being contaminated or with foreign matter being bitten in, the aluminum wire 1 and the wire connection terminal portion 4 may not be physically joined, or may be peeled off after wire bonding, etc., so that the wire bonding portion 2 may be slightly separated from the wire connection terminal portion 4 and float.

[0054] In such a state where the wire bonding portion 2 floats, the height position of the wire bonding portion 2 becomes higher than the height position when wire bonding is performed normally. Therefore, by measuring the height position of the wire bonding portion 2 with the laser displacement meter 302, it is possible to detect an abnormality in the bonding between the aluminum wire 1 and the wire connection terminal portion 4.

[0055] Note that when the reference of the height position of the wire bonding portion 2 is set in absolute coordinates, it is affected by the inclination of the inspection stage 201, the thickness variation of the substrate 5, and the warpage of the substrate 5. Therefore, it is desirable to use as a reference the height position of the surface (the surface in the Z direction) of the wire connection terminal portion 4 as close as possible to the wire bonding portion 2.

[0056] Also, although not shown, the laser displacement meter 302 may measure multiple reflections from the surrounding metal surfaces in a method of measuring the distance by triangulation of the position where the laser 303 hits, and there is a high possibility of mismeasurement. Therefore, it is desirable that the laser displacement meter be of the confocal method type that measures the distance from the color (wavelength) of the reflected light.

[0057] Also, the laser 303 of the laser displacement meter 302 may be of a type that has a spot shape and measures a local single point, or may be of a type that has a line shape and measures the height position in a line-shaped region.

[0058] Next, the inspection method according to Embodiment 2 will be described. FIG. 8 is a flowchart of the inspection method according to Embodiment 2.

[0059] As shown in FIG. 8, first, the control device 301 positions the inspection stage 201 at a determined position (step S11), and the imaging device 105 images the aluminum wire 1 (step S12). The control device 301 acquires two-dimensional position information of the bright regions existing in the wire bonding portion 2 and the bright regions existing in the vertex portion 3 from the image captured by the imaging device 105 (step S13).

[0060] The control device 301 positions the laser displacement meter 302 so that the laser 303 of the laser displacement meter 302 is irradiated to the position of the acquired two-dimensional position information of the wire bonding portion 2 (step S14). Specifically, the control device 301 positions the laser displacement meter 302 by moving the inspection stage 201 in the two-dimensional direction.

[0061] Next, the laser displacement meter 302 applies the laser 303 to the bright region where the wire bonding portion 2 exists, and measures the height position of the wire bonding portion 2 (step S15).

[0062] Next, the control device 301 determines the floating of the wire bonding portion 2 (step S16). Specifically, the control device 301 compares the measured height position of the wire bonding portion 2 with the height position of the wire bonding portion 2 preset in the memory of the control device 301. If the comparison result is within a predetermined range, it is determined that the wire bonding portion 2 has no floating and is normal. If the comparison result is outside the predetermined range, it is determined that the wire bonding portion 2 has floating and is abnormal.

[0063] As described above, the inspection apparatus 100 according to Embodiment 2 further includes a laser displacement meter 302 that is disposed above the aluminum wire 1 (in the Z direction) and measures the height position of the aluminum wire 1, and a moving mechanism that moves the semiconductor device 10 in two-dimensional directions. The moving mechanism moves the semiconductor device 10 so that the laser displacement meter 302 is positioned above the wire bonding portion 2 (in the Z direction). The laser displacement meter 302 irradiates the laser 303 onto a region that is brighter in luminance than the surroundings existing in the wire bonding portion 2, and measures the height position of the wire bonding portion 2.

[0064] Therefore, it is possible to detect the lifting of the wire bonding portion 2 that is difficult to discriminate only by observing the appearance.

[0065] <Modification Example of Embodiment 2> In Embodiment 2, the positioning of the laser displacement meter 302 is performed by moving the inspection stage 201 in two-dimensional directions. However, the laser displacement meter 302 may be configured to be movable in two-dimensional directions, and the laser displacement meter 302 may perform its own positioning by moving in two-dimensional directions. Further, the inspection stage 201 may be configured to be movable in the height direction (Z-axis direction) in order to adjust the measurement distance of the laser displacement meter 302, or the laser displacement meter 302 may be configured to be movable in the height direction (Z-axis direction).

[0066] <Embodiment 3> Next, the inspection apparatus 100 according to Embodiment 3 will be described. FIG. 9 is a side view of the inspection apparatus 100 according to Embodiment 3. In Embodiment 3, the same components as those described in Embodiments 1 and 2 are denoted by the same reference numerals and the description thereof is omitted.

[0067] In Embodiment 3, in addition to the configuration of Embodiment 2, as shown in FIG. 9, the inspection apparatus 100 further includes a laser displacement meter 312. That is, the inspection apparatus 100 includes two laser displacement meters 302 and 312. The two laser displacement meters 302 and 312 are arranged side by side in the X-axis direction. The laser displacement meter 302 is arranged above the aluminum wire 1 (in the Z direction), and the laser displacement meter 312 is arranged above the portion of the semiconductor device 10 located in the vicinity of the wire bonding portion 2 (in the Z direction). The portion of the semiconductor device 10 located in the vicinity of the wire bonding portion 2 is the electrode 6, the semiconductor chip 7, or the substrate 5 of the semiconductor device 10. In FIG. 9, the laser displacement meter 312 is arranged above the semiconductor chip 7 (in the Z direction).

[0068] By moving the inspection stage 201 in the two-dimensional direction with respect to the position of the two-dimensional coordinates of the wire bonding portion 2 detected by the coaxial illumination 103, the wire bonding portion 2 is positioned so as to exactly hit the laser 303 irradiated by the laser displacement meter 302.

[0069] At the same time, the laser 313 irradiated by the laser displacement meter 312 hits the surface of the semiconductor chip 7 which is the portion of the semiconductor device 10 located in the vicinity of the wire bonding portion 2, and the height position of the wire bonding portion 2 and the height position of the semiconductor chip 7 located in the vicinity thereof can be measured simultaneously.

[0070] Note that the inspection method according to Embodiment 3 is the same as that in the case of Embodiment 2 except that the wire bonding portion 2 and the portion of the semiconductor device 10 located in the vicinity of the wire bonding portion 2 are measured simultaneously, and thus the description thereof is omitted.

[0071] In Embodiment 2, it was necessary to move the inspection stage 201 in order to measure the height position of the wire bonding portion 2 and the height position of the portion of the semiconductor device 10 located in the vicinity of the wire bonding portion 2 as the reference height position.

[0072] On the other hand, the inspection apparatus 100 according to Embodiment 3 includes laser displacement meters 302 and 312. One of the laser displacement meters 302 and 312 irradiates the laser 303 of one of the laser displacement meters 302 onto a region brighter than the surroundings existing in the wire bonding portion 2, measures the height position of the wire bonding portion 2, and at the same time, irradiates the laser 313 of the other laser displacement meter 312 onto a portion of the semiconductor device 10 located near the wire bonding portion 2 to measure the height position of the joint portion, thereby measuring the difference between the height position of the wire bonding portion 2 and the height position of the portion of the semiconductor device 10.

[0073] Therefore, it is possible to simultaneously measure the height position of the wire bonding portion 2 and the reference height position without moving the inspection stage 201. Thereby, the inspection time for the floating of the wire bonding portion 2 can be shortened.

[0074] <Modification Example of Embodiment 3> In Embodiment 3, the positioning of the laser displacement meters 302 and 312 is performed by moving the inspection stage 201 in the two-dimensional direction. However, the laser displacement meters 302 and 312 may be configured to be movable in the two-dimensional direction, and the laser displacement meters 302 and 312 may perform their own positioning by moving in the two-dimensional direction. Further, the inspection stage 201 may be configured to be movable in the height direction (Z-axis direction) in order to adjust the measurement distance of the laser displacement meters 302 and 312, or the laser displacement meters 302 and 312 may be configured to be movable in the height direction (Z-axis direction).

[0075] <Embodiment 4> Next, the inspection apparatus 100 according to Embodiment 4 will be described. FIG. 10 is a side view showing the bonding state of the aluminum wire 1, the wire connection terminal portion 4, and the electrode 6 in Embodiment 4. FIG. 11 is a top view showing the bonding state of the aluminum wire 1, the wire connection terminal portion 4, and the electrode 6 in Embodiment 4. In Embodiment 4, the same components as those described in Embodiments 1 to 3 are denoted by the same reference numerals and the description thereof is omitted.

[0076] In Embodiment 1, the two-dimensional position information of the region brighter than the surrounding area existing in the obtained vertex portion 3 and the region brighter than the surrounding area existing in the wire bonding portion 2 is compared with the two-dimensional position information of the vertex portion 3 and the wire bonding portion 2 preset in the memory of the control device 301. When there is a difference of a certain level or more, it is determined that there is an abnormality in wire deformation or bonding position.

[0077] On the other hand, in Embodiment 4, for more accurate inspection than in the case of Embodiment 1, it aims to accurately grasp the overall shape of the aluminum wire 1. The configuration of the inspection device 100 according to Embodiment 4 is the same as that in the case of Embodiment 1.

[0078] The necessity of accurately grasping the overall shape of the aluminum wire 1 will be described. As shown in FIG. 10, a semiconductor chip 7 is mounted on the upper surface (the surface in the Z direction) of the substrate 5 via solder 50. One end of the aluminum wire 1 is wire-bonded to the wire connection terminal portion 4 (in the Z direction) formed on the semiconductor chip 7 by the wedge bonding method. The other end of the aluminum wire 1 is wire-bonded to the electrode 6 (in the Z direction) by the wedge bonding method.

[0079] As shown in FIG. 11, similar to the case of FIG. 3, since the illumination light irradiated from the coaxial illumination 103 (see FIG. 1) is reflected by the wire bonding portion 2 and the vertex portion 3, there are regions with brighter luminance in the regions with darker luminance, and the two-dimensional position information of each can be measured from the image.

[0080] Regarding the entire aluminum wire 1 as well, similar to the case of FIG. 3, it is observed as a region with overall darker luminance in the image. However, the solder 50 protruding from the periphery of the semiconductor chip 7 and the contour 51 of the three-dimensional object are also observed as regions with darker luminance in the image, and it is difficult to grasp the overall shape of the aluminum wire 1 only by the brightness. Here, the three-dimensional object is the substrate 5 and the electrode 6.

[0081] Therefore, in Embodiment 4, the overall shape of the aluminum wire 1 is grasped by tracking a dark luminance region that continues from the wire bonding part 2, which is a region brighter in luminance than its surroundings and exists at both ends of the aluminum wire 1, toward a region brighter in luminance than its surroundings and existing at the vertex part 3 as well.

[0082] For example, in the arrow directions of C and D in FIG. 11, a dark luminance region exists in the solder 50 and extends, but the vertex part 3 does not exist at the end of this dark luminance region. On the other hand, in the arrow direction of B in FIG. 11, a dark luminance region extends, and the vertex part 3 exists at the end of this dark luminance region. Also, for example, in the arrow directions of F and G in FIG. 11, the contour 51 of the electrode 6 is a region with a dark luminance due to the shadow of illumination, but the vertex part 3 does not exist at the end of this dark luminance region. On the other hand, the vertex part 3 exists at the end in the arrow direction of E.

[0083] In this way, starting from the bright luminance region existing in the wire bonding part 2 and tracking the dark luminance region, when the vertex part 3 exists at the end of the dark luminance region, it is determined that the dark luminance region is the aluminum wire 1, and when the vertex part 3 does not exist at the end of the dark luminance region, it is determined that the dark luminance region is not the aluminum wire 1. Through these determinations, the accurate overall shape of the aluminum wire 1 can be grasped.

[0084] Next, the inspection method according to Embodiment 4 will be described. FIG. 12 is a flowchart of the inspection method according to Embodiment 4.

[0085] As shown in FIG. 12, first, the control device 301 positions the inspection stage 201 at a determined position (step S21), and the imaging device 105 images the aluminum wire 1 (step S22). The control device 301 acquires the two-dimensional position information of the bright luminance region existing in the wire bonding part 2 and the bright luminance region existing in the vertex part 3 from the image captured by the imaging device 105 (step S23).

[0086] The control device 301 tracks a region with a darker luminance from the position of the wire bonding part 2 to the position of the vertex part 3 in the image (step S24). If the vertex part 3 is at the tracked position (Yes in step S25), the control device 301 determines that the tracked region with a darker luminance is the aluminum wire 1.

[0087] On the other hand, if the vertex part 3 is not at the tracked position and the region with a darker luminance is interrupted (No in step S25), the control device 301 determines that the tracked region with a darker luminance is not the aluminum wire 1.

[0088] Finally, the control device 301 determines the presence or absence of wire deformation from the shape of the region with a darker luminance determined to be the aluminum wire 1 (step S26). For example, the control device 301 compares the obtained shape of the aluminum wire 1 with the shape of the aluminum wire 1 preset in the memory of the control device 301, and determines that there is wire deformation if there is a difference of a certain level or more, and determines that there is no wire deformation if there is no difference of a certain level or more.

[0089] In the first embodiment, the presence or absence of wire deformation was determined using only the two-dimensional position information of the wire bonding part 2 and the vertex part 3 of the aluminum wire 1. However, in the fourth embodiment, by accurately grasping the shape of the part of the aluminum wire 1 other than the wire bonding part 2 and the vertex part 3, it is possible to determine wire deformation with higher accuracy.

[0090] Here, the details of the method for tracking the region with a darker luminance performed by the control device 301 in step S24 will be described. FIG. 13 is an explanatory diagram for explaining the inspection method according to the fourth embodiment.

[0091] The control device 301 also acquires the luminance data of the pixels in addition to the two-dimensional coordinate information from the image. The image includes numerical data of luminance with the number of pixels of the number of vertical pixels × the number of horizontal pixels, and the smaller the numerical value of the luminance data, the darker the luminance, and the larger the numerical value, the brighter the luminance. For example, in 8-bit luminance data, the luminance of each pixel is represented by a numerical value from 0 to 255.

[0092] When the control device 301 acquires the image shown in FIG. 11, a straight line extending from the wire bonding portion 2 to the vertex portion 3 is calculated. When the origin is overlapped with the image of FIG. 11 with the wire bonding portion 2 as the origin, it becomes as shown in FIG. 13. The shape of the aluminum wire 1 is searched within a range of -Δ to +Δ in the Y-axis direction (inside the frame of FIG. 13) preset in the Y-axis direction based on the pixels overlapping the obtained straight line (y = ax).

[0093] First, the control device 301 starts from the origin (wire bonding portion 2) at the left end and first performs an upper side search of the aluminum wire 1. In the upper side search, the luminance change is examined within the range of the frame in the -Y direction from the position of +Δ in the Y-axis direction of the origin. By examining the luminance change in the direction of the upper side search, if a point where the luminance changes by more than a preset luminance is found at a point where the change is from white to black, that point is determined as the position of the upper side of the aluminum wire 1.

[0094] Next, the control device 301 performs a lower side search of the aluminum wire 1. In the lower side search, the luminance change is examined within the range of the frame in the Y direction from the position of -Δ in the Y-axis direction of the origin. By examining the luminance change in the direction of the lower side search, if a point where the luminance changes by more than a preset luminance is found at a point where the change is from white to black, that point is determined as the position of the lower side of the aluminum wire 1.

[0095] The distance between the point determined as the position of the upper side of the aluminum wire 1 and the point determined as the position of the lower side is calculated. If it is within the range of the thickness of the aluminum wire 1 preset in the memory of the control device 301, it is determined that the detected upper side and lower side of the aluminum wire 1 are correctly detected.

[0096] These processes are repeatedly performed between the wire bonding portion 2 and the vertex portion 3, and the detected upper side and lower side of the aluminum wire 1 represent the shape of the aluminum wire 1. If the distance between the upper side and the lower side of the aluminum wire 1 is outside the range of the thickness of the aluminum wire 1 preset in the memory of the control device 301, it is regarded as data loss.

[0097] As described above, in the inspection apparatus according to the fourth embodiment, the control device 301 detects the two-dimensional shape of the aluminum wire 1 by tracking a region darker in luminance than the surroundings from the position of the wire bonding portion 2 to the position of the apex portion 3 in the image.

[0098] Therefore, since the overall shape of the aluminum wire 1 can be accurately grasped, the inspection accuracy regarding the deformation of the aluminum wire 1 is improved as compared with the case of the first embodiment.

[0099] It should be noted that the respective embodiments can be freely combined, or the respective embodiments can be appropriately deformed or omitted.

[0100] Hereinafter, aspects of the present disclosure will be collectively described as appendices.

[0101] (Appendix 1) An inspection apparatus for detecting an abnormality of a work piece to be inspected in which both ends are wire-bonded to a joint portion of a semiconductor device by a wedge bonding method, wherein the work piece to be inspected is a wire having a diameter of 100 μm or more, an imaging device disposed above the wire and imaging an image of the wire to acquire two-dimensional position information of the wire; a coaxial illumination disposed coaxially with the imaging device and irradiating coaxial illumination light to the wire; a control device that acquires the two-dimensional position information of a region brighter in luminance than the surroundings existing at the apex portion of the wire and a region brighter in luminance than the surroundings existing at a wire bonding portion that is a joint portion of the wire from the image; An inspection apparatus comprising:

[0102] (Appendix 2) The control device compares the two-dimensional position information of the region where the brightness is brighter than the surroundings existing at the vertex portion and the region where the brightness is brighter than the surroundings existing at the wire bonding portion, which are acquired, with the two-dimensional position information of the vertex portion and the wire bonding portion set in advance, and determines that there is an abnormality in wire deformation or bonding position when there is a difference of a certain level or more. The inspection device according to Supplementary Note 1.

[0103] (Supplementary Note 3) A laser displacement meter disposed above the wire for measuring the height position of the wire, and a moving mechanism for moving the semiconductor device in two-dimensional directions. The inspection device according to Supplementary Note 1, further comprising: The moving mechanism moves the semiconductor device so that the laser displacement meter is positioned above the wire bonding portion. The laser displacement meter applies a laser to a region where the brightness is brighter than the surroundings existing at the wire bonding portion to measure the height position of the wire bonding portion. The inspection device according to Supplementary Note 1.

[0104] (Supplementary Note 4) Two laser displacement meters are provided. One of the two laser displacement meters applies a laser to a region where the brightness is brighter than the surroundings existing at the wire bonding portion to measure the height position of the wire bonding portion. At the same time, the other laser displacement meter applies a laser to a portion of the semiconductor device located in the vicinity of the wire bonding portion to measure the height position of the portion of the semiconductor device, thereby measuring the difference between the height position of the wire bonding portion and the height position of the portion of the semiconductor device. The inspection device according to Supplementary Note 3.

[0105] (Supplementary Note 5) The work to be inspected is a plurality of wires having a diameter of 100 μm or more. The control device acquires two-dimensional position information of an area where the luminance is brighter than the surroundings existing at the vertex portions of the plurality of wires from the image, measures the distances between the plurality of vertex portions of the plurality of wires from the acquired two-dimensional position information, and compares the measured distances between the vertex portions with the distances between the plurality of vertex portions set in advance. The inspection device according to Supplementary Note 1.

[0106] (Supplementary Note 6) The control device detects the two-dimensional shape of the wire by tracking an area where the luminance is darker than the surroundings from the position of the wire bonding portion to the position of the vertex portion in the image. The inspection device according to Supplementary Note 1.

[0107] (Supplementary Note 7) An inspection method for detecting an abnormality in a workpiece to be inspected in which both ends are wire-bonded to a portion to be joined of a semiconductor device by a wedge bonding method, The workpiece to be inspected is a wire having a diameter of 100 μm or more, A step of imaging an image of the wire from above the wire by an imaging device to acquire two-dimensional position information of the wire; A step of irradiating coaxial illumination light to the wire from coaxially with the imaging device; A step of acquiring two-dimensional position information of an area where the luminance is brighter than the surroundings existing at the vertex portion of the wire and an area where the luminance is brighter than the surroundings existing at the wire bonding portion which is the joining portion of the wire from the image; An inspection method comprising:

[0108] (Supplementary Note 8) After the step of acquiring the two-dimensional position information, the two-dimensional position information of the area where the luminance is brighter than the surroundings existing at the acquired vertex portion and the area where the luminance is brighter than the surroundings existing at the wire bonding portion is compared with the two-dimensional position information of the vertex portion and the wire bonding portion set in advance, and when there is a difference of a certain level or more, it is determined that there is an abnormality in the wire deformation or the bonding position. The inspection method according to Supplementary Note 7.

[0109] (Supplementary Note 9) After the step of acquiring the two-dimensional position information, a step of measuring the height position of the wire from above the wire by a laser displacement meter; and a step of moving the semiconductor device in a two-dimensional direction, and further includes: In the step of moving the semiconductor device in a two-dimensional direction, the semiconductor device is moved so that the laser displacement meter is positioned above the wire bonding portion, In the step of measuring the height position of the wire, a laser is applied to a region where the luminance is brighter than the surroundings existing in the wire bonding portion, and the height position of the wire bonding portion is measured. The inspection method according to Supplementary Note 7.

[0110] (Supplementary Note 10) The step of measuring the height position of the wire is performed by two of the laser displacement meters, The two laser displacement meters apply the laser of one of the laser displacement meters to a region where the luminance is brighter than the surroundings existing in the wire bonding portion to measure the height position of the wire bonding portion. At the same time, the laser of the other laser displacement meter is applied to a portion of the semiconductor device located near the wire bonding portion to measure the height position of the portion of the semiconductor device, thereby measuring the difference between the height position of the wire bonding portion and the height position of the portion of the semiconductor device. The inspection method according to Supplementary Note 9.

[0111] (Supplementary Note 11) The workpiece to be inspected is a plurality of wires having a diameter of 100 μm or more, In the step of acquiring the two-dimensional position information, the two-dimensional position information of a region where the luminance is brighter than the surroundings existing at the apex portions of the plurality of wires is acquired from the image, the distance between the plurality of apex portions of the plurality of wires is measured from the acquired two-dimensional position information, and the measured distance between the apex portions is compared with a preset distance between the plurality of apex portions. The inspection method according to Supplementary Note 7.

[0112] (Supplementary Note 12) After the step of obtaining the two-dimensional position information, the method for inspection according to appended claim 7, further comprising a step of detecting a two-dimensional shape of the wire by tracking a region darker in luminance than the surroundings from the position of the wire bonding portion to the position of the vertex portion in the image.

Explanation of reference numerals

[0113] 1, 1a, 1b Aluminum wire, 2 Wire bonding portion, 3 Vertex portion, 4, 4a, 4b Wire connection terminal portion, 6, 6a, 6b Electrode, 10 Semiconductor device, 100 Inspection device, 103 Coaxial illumination, 105 Imaging device, 201 Inspection stage, 202 Motor, 203 Ball screw, 301 Control device, 302 Laser displacement meter.

Claims

1. An inspection apparatus for detecting abnormalities in a workpiece in which both ends are wire-bonded by the wedge bonding method to the bonded portions of a semiconductor device, wherein the workpiece is a wire having a diameter of 100 μm or more, an imaging device that is disposed above the wire and captures an image of the wire to obtain two-dimensional position information of the wire; a coaxial illumination that is disposed coaxially with the imaging device and irradiates coaxial illumination light onto the wire; and a control device that obtains two-dimensional position information of a region where the luminance is brighter than the surroundings existing at the apex of the wire and a region where the luminance is brighter than the surroundings existing at the wire bonding portion which is the bonding location of the wire from the image, The inspection apparatus is provided with.

2. The control device compares the two-dimensional position information of the region where the luminance is brighter than the surroundings existing at the obtained apex and the region where the luminance is brighter than the surroundings existing at the wire bonding portion with the two-dimensional position information of the preset apex and the wire bonding portion, and determines that there is an abnormality in wire deformation or bonding position when there is a difference of a certain level or more. The inspection apparatus according to Claim 1.

3. a laser displacement meter that is disposed above the wire and measures the height position of the wire; and a moving mechanism that moves the semiconductor device in two-dimensional directions, and further includes, the moving mechanism moves the semiconductor device so that the laser displacement meter is positioned above the wire bonding portion, the laser displacement meter applies a laser to a region where the luminance is brighter than the surroundings existing at the wire bonding portion and measures the height position of the wire bonding portion. The inspection apparatus according to Claim 1.

4. Two laser displacement meters are provided, The two laser displacement meters apply the laser of one of the laser displacement meters to a region where the luminance is brighter than the surroundings existing at the wire bonding portion and measure the height position of the wire bonding portion. At the same time, the laser of the other laser displacement meter is applied to the portion of the semiconductor device located in the vicinity of the wire bonding portion to measure the height position of the portion of the semiconductor device, thereby measuring the difference between the height position of the wire bonding portion and the height position of the portion of the semiconductor device. The inspection apparatus according to Claim 3.

5. The workpiece is a plurality of wires having a diameter of 100 μm or more, The control device acquires two-dimensional position information of an area where the luminance is brighter than the surroundings existing at the vertex portions of the plurality of wires from the image, measures the distances between the plurality of vertex portions of the plurality of wires from the acquired two-dimensional position information, and compares the measured distances between the vertex portions with the distances between the plurality of vertex portions set in advance. The inspection apparatus according to claim 1.

6. The control device detects the two-dimensional shape of the wire by tracking an area where the luminance is darker than the surroundings from the position of the wire bonding portion to the position of the vertex portion in the image. The inspection apparatus according to claim 1.

7. An inspection method for detecting an abnormality of an inspection target work in which both ends are wire-bonded to a bonded portion of a semiconductor device by a wedge bonding method, The inspection target work is a wire having a diameter of 100 μm or more, A step of imaging an image of the wire to acquire two-dimensional position information of the wire from above the wire by an imaging device; A step of irradiating coaxial illumination light to the wire from coaxially with the imaging device; A step of acquiring two-dimensional position information of an area where the luminance is brighter than the surroundings existing at the vertex portion of the wire and an area where the luminance is brighter than the surroundings existing at the wire bonding portion which is the bonding location of the wire from the image; An inspection method comprising:

8. After the step of acquiring the two-dimensional position information, comparing the two-dimensional position information of the area where the luminance is brighter than the surroundings existing at the acquired vertex portion and the area where the luminance is brighter than the surroundings existing at the wire bonding portion with the two-dimensional position information of the vertex portion and the wire bonding portion set in advance, and determining that there is an abnormality in wire deformation or bonding position when there is a difference of a certain level or more. The inspection method according to claim 7.

9. After the step of acquiring the two-dimensional position information, A step of measuring the height position of the wire from above the wire by a laser displacement meter; A step of moving the semiconductor device in a two-dimensional direction, further comprising: In the step of moving the semiconductor device in a two-dimensional direction, the semiconductor device is moved so that the laser displacement meter is positioned above the wire bonding portion. In the step of measuring the height position of the wire, a laser is applied to an area where the luminance is brighter than the surroundings existing in the wire bonding portion, and the height position of the wire bonding portion is measured. The inspection method according to claim 7.

10. The step of measuring the height position of the wire is performed by the two laser displacement meters. The two laser displacement meters apply the laser of one of the laser displacement meters to an area where the luminance is brighter than the surroundings existing in the wire bonding portion, measure the height position of the wire bonding portion, and at the same time, apply the laser of the other laser displacement meter to the portion of the semiconductor device located near the wire bonding portion, measure the height position of the portion of the semiconductor device, and thereby measure the difference between the height position of the wire bonding portion and the height position of the portion of the semiconductor device. The inspection method according to claim 9.

11. The work to be inspected is a plurality of wires having a diameter of 100 μm or more. In the step of acquiring the two-dimensional position information, the two-dimensional position information of an area where the luminance is brighter than the surroundings existing at the vertex portions of the plurality of wires is acquired from the image, the distance between the plurality of vertex portions of the plurality of wires is measured from the acquired two-dimensional position information, and the measured distance between the vertex portions is compared with the preset distance between the plurality of vertex portions. The inspection method according to claim 7.

12. After the step of acquiring the two-dimensional position information, the inspection method according to claim 7 further includes a step of detecting the two-dimensional shape of the wire by tracking an area where the luminance is darker than the surroundings from the position of the wire bonding portion to the position of the vertex portion in the image.

Images