DEFECT DETECTION DEVICE AND DEFECT DETECTION METHOD

A defect detection device (100) which detects a defect of a semiconductor device (10) includes: a standing wave generator (20), applying a standing wave (30) to the semiconductor device (10) to apply a suction force to a wire (13); cameras (41, 42); and a control part (50), adjusting an operation of a standing wave generator (20) and performing defect detection on the semiconductor device (10). The control part (50) captures, by using the cameras (41, 42), a first image of the semiconductor device (1) of a first state in which the suction force is applied to the wire (13) and a second image of the semiconductor device (10) of a second state in which the suction force applied to the wire (13) is smaller than the first stage, and compares the first image and the second image to perform defect detection.

TECHNICAL FIELD

The invention relates to a configuration of a defect detection device performing defect detection on an inspection target by using ultrasonic waves and a defect detection method for performing defect detection by using ultrasonic waves.

RELATED ART

In the manufacture of a semiconductor device, wire bonding for connecting an electrode of a substrate and an electrode of a semiconductor element by using a wire is performed. In wire bonding, a bonding defect may occur at the bonding part between the electrode of the substrate and the wire or the bonding part between the electrode of the semiconductor element and the wire. Since such connection defect is difficult to determine visually, a method in which a suitable current is input from the wire to the semiconductor chip, the value of the flowing current is measured, and an electrical connection defect is determined is used (for example, see Patent Document 1).

It addition, it may also be that the bonding part is monitored by using a scanning electron microscope (SEM), and the bonding state is determined (for example, see Patent Document 2).

CITATION LIST

Patent Literature

SUMMARY OF INVENTION

Technical Problem

However, in wire bonding, a bonding defect that is difficult to detect through an image may occur, such as the case where the bonded wire is slightly raised from the surface of the electrode, the case where the wire contacts the electrode but is not bonded thereto, or the case where a ball neck and a looping wire are separated by a small crack.

Regarding such small bonding defect, for example, a method for checking bonding strength by pulling the wire after bonding is available. However, it may take a long time if a pulling test is carried out for all the bonding positions, and productivity may be significantly reduced.

Therefore, an objective of the invention is to detect a defect of an inspection target within a short time by using a simple configuration.

Solution to Problem

A defect detection device according to the invention detects a defect of an inspection target in which a bonding article is bonded to a bonded article. The defect detection device includes: a standing wave generator, generating a standing wave, and applying the standing wave that is generated to the inspection target to apply a suction force to the bonding article; an image capturing device, capturing an image of the inspection target; and a control part, adjusting an operation of the standing wave generator and performing defect detection on the inspection target. The control part captures, by using the image capturing device, a first image of the inspection target of a first state in which the suction force is applied to the bonding article and a second image of the inspection target of a second state in which the suction force applied to the bonding article is smaller than the first state. The first image of the first state and the second image of the second state are compared to perform defect detection on the inspection target.

In this way, when the standing wave is applied to the inspection target, the bonding article of the inspection target is sucked to a node of the sound of the standing wave and deformed. Therefore, by capturing the first image of the inspection target of the first state in which the suction force is applied to the bonding article and the second image of the inspection target of the second state in which the suction force applied to the bonding article is smaller than the first state and comparing the first image and the second image, defect detection can be performed. In addition, by applying the standing wave to multiple inspection targets at the same time to compare the first images and the second images of the multiple inspection targets, defect detection on multiple inspection targets can be performed within a short time.

In the defect detection device according to the invention, the standing wave generator may be at least one set of ultrasonic wave generators disposed to face each other.

Accordingly, the standing wave can be generated by using a simple method.

In the defect detection device according to the invention, the standing wave generator may be formed by an ultrasonic wave generator and a reflective surface disposed to face the ultrasonic wave generator.

Accordingly, the standing wave can be generated by using a simple method.

In the defect detection device according to the invention, the standing wave generator may be disposed so that a position of a node of a sound pressure of the standing wave is right above the inspection target.

In this way, by disposing the position of the node of the sound pressure of the standing wave right above the inspection target, the defect of the inspection target can be detected through deformation detection, as the inspection target where a defect is present is pulled upward toward the node of the sound pressure.

In the defect detection device according to the invention, the ultrasonic wave generator may be an ultrasonic wave phased array formed by a plurality of ultrasonic wave speakers or ultrasonic wave vibrators, and one or more of a frequency, an amplitude, and a phase of an ultrasonic wave generated by each of the ultrasonic wave speakers or each of the ultrasonic wave vibrators may be set, so that a focus region of the standing wave generated between the set of ultrasonic wave phased arrays is right above the inspection target.

In the defect detection device according to the invention, the ultrasonic wave generator may be an ultrasonic wave phased array formed by a plurality of ultrasonic wave speakers or ultrasonic wave vibrators, and one or more of a frequency, an amplitude, and a phase of an ultrasonic wave generated by each of the ultrasonic wave speakers or each of the ultrasonic wave vibrators may be set, so that a focus region of the standing wave generated between the ultrasonic wave phased array and the reflexive surface is right above the inspection target.

In this way, by setting each parameter so that the focus region of the standing wave where the sound is enhanced is right above the inspection target, the node of the sound pressure with a large suction force can be located right above the inspection target, and the deformation of the inspection target can be increased. Accordingly, the detection accuracy for the defect of the inspection target can be increased.

In the defect detection device according to the invention, the defect detection device may include a stage. The bonded article may be sucked and fixed to an upper surface of the stage. The ultrasonic wave phased array may generate ultrasonic waves traveling in a direction along the upper surface of the stage. One or more of a frequency, an amplitude, and a phase of the ultrasonic wave generated by each of the ultrasonic wave speakers or each of the ultrasonic wave vibrators may be set, so that the focus region of the standing wave is right above the bonding article of the inspection target.

In this way, the ultrasonic waves traveling in the direction along the upper surface of the stage are generated from the ultrasonic wave phased array to generate the standing wave, and by changing each parameter, the focus region can be moved in the upper-lower direction.

Therefore, it can be set that the focus region can be located right above the bonding article while the position of the ultrasonic wave phased array is fixed. Accordingly, the focus region of the standing wave where the sound is enhanced can be located right above the bonding article to suck the bonding article upward by using a large suction force, and the deformation of the bonding article where a defect is present can be increased. Accordingly, the detection accuracy for the bonding article where a defect is present can be increased.

In the defect detection device according to the invention, the defect detection device may include a stage. The bonded article may be sucked and fixed to an upper surface of the stage. The reflexive surface may be a surface of the bonded article sucked and fixed to the upper surface of the stage. The ultrasonic wave generator may be disposed above the stage, and may generate an ultrasonic wave with a frequency that a position of a node of a sound pressure of the standing wave generated between the ultrasonic wave generator and the surface of the bonded article is right above the bonding article.

In this way, by disposing the ultrasonic wave phased array above the stage, the configuration space of the defect inspection device can be reduced.

In the defect detection device according to the invention, the ultrasonic wave generator may be an ultrasonic wave phased array formed by a plurality of ultrasonic wave speakers or ultrasonic wave vibrators.

In the defect detection device according to the invention, the inspection target may be a semiconductor device formed by a substrate, a semiconductor element installed to the substrate, and a wire bonded to an electrode of the semiconductor element and an electrode of the substrate to connect each of the electrodes. The bonded article of the inspection target may be the substrate and the semiconductor element installed to the substrate, and the bonding article of the inspection target may be the wire.

A defect detection method according to the invention detects a defect of an inspection target in which a bonding article is bonded to a bonded article. The defect detection method includes: a process of preparing a defect detection device comprising: a standing wave generator, generating a standing wave and applying the standing wave that is generated to the inspection target to apply a suction force to the bonding article; and an image capturing device, capturing an image of the inspection target; a first image capturing process, capturing, by using the image capturing device, a first image of the inspection target of a first state in which the suction force is applied to the bonding article; a second image capturing process, capturing, by using the image capturing device, a second image of the inspection target of a second state in which the suction force applied to the bonding article is smaller than the first state; and a defect detection process, comparing the first image of the first state and the second image of the second state to perform defect detection on the inspection target.

In this way, a defect of an inspection target can be detected within a short time by using a simple configuration.

The defect detection method according to the invention may include a position adjustment process, adjusting a relative position of the standing wave generator to the inspection target, so that a position of a node of a sound pressure of the standing wave is right above the inspection target.

In the defect detection method according to the invention, the standing wave generator may be configured by disposing ultrasonic wave phased arrays facing each other, the ultrasonic wave phased arrays being formed by a plurality of ultrasonic wave speakers or ultrasonic wave vibrators, and the defect inspection method includes a focus region adjustment process, adjusting one or more of a frequency, an amplitude, and a phase of an ultrasonic wave generated by each of the ultrasonic wave speakers or each of the ultrasonic wave vibrators, so that a focus region of the standing wave generated between the ultrasonic wave phased arrays is right above the inspection target.

In the defect detection method according to the invention, the ultrasonic wave generator may be formed by an ultrasonic wave phased array formed by a plurality of ultrasonic wave speakers or ultrasonic wave vibrators and a reflexive surface disposed to face the ultrasonic wave phased array, and the defect inspection method may include a focus region adjustment process, adjusting one or more of a frequency, an amplitude, and a phase of an ultrasonic wave generated by each of the ultrasonic wave speakers or each of the ultrasonic wave vibrators, so that a focus region of the standing wave generated between the ultrasonic wave phased array and the reflexive surface is right above the inspection target.

Accordingly, the node of the sound pressure with a large suction force can be located right above the inspection target to reliably suck and deform the inspection target, and the detection accuracy for the defect can be increased.

In the defect detection method according to the invention, the defect inspection device may include a stage, and the bonded article is sucked and fixed to an upper surface of the stage, and the ultrasonic wave phased array may generate ultrasonic waves traveling in a direction along the upper surface of the stage. In the focus region adjustment process, and a phase of an ultrasonic wave generated by each of the ultrasonic wave speakers or each of the ultrasonic wave vibrators may be adjusted, so that the focus region of the standing wave is right above the bonding article.

In this way, the ultrasonic waves traveling in the direction along the upper surface of the stage are generated from the ultrasonic wave phased array to generate the standing wave, and by adjusting each parameter, the focus region can be moved in the upper-lower direction. Therefore, it can be adjusted that the focus region can be located right above the bonding article while the position of the ultrasonic wave phased array is fixed. Accordingly, the focus region of the standing wave where the sound is enhanced can be located right above the bonding article to suck the bonding article upward by using a large suction force, and the deformation of the bonding article where a defect is present can be increased. Accordingly, the detection accuracy for the bonding article where a defect is present can be increased.

In the defect detection method according to the invention, the defect inspection device may include a stage, and the bonded article is sucked and fixed to an upper surface of the stage, and the standing wave generator may be formed by a surface of the bonded article sucked and fixed to the upper surface of the stage, and an ultrasonic wave phased array formed by a plurality of ultrasonic wave speakers or ultrasonic wave vibrators and disposed above the stage so as to face the upper surface of the stage. The defect inspection method may include a focus region position adjustment process, adjusting one or more of a frequency, an amplitude, and a phase of an ultrasonic wave generated by each of the ultrasonic speakers or each of the ultrasonic vibrators, and adjusting a position of a focus region of the standing wave generated between the ultrasonic phased array and the surface of the bonded article in a direction along the upper surface of the stage.

In this way, by adjusting the position of the focus region of the standing wave where the sound is enhanced in a direction along the upper surface of the stage, even if the inspection target is large, the defect inspection on the inspection target can be performed without moving the inspection target or the ultrasonic wave phased array.

In the defect detection method according to the invention, the inspection target may be a semiconductor device formed by a substrate, a semiconductor element installed to the substrate, and a wire bonded to an electrode of the semiconductor element and an electrode of the substrate to connect each of the electrodes. The bonded article of the inspection target may be the substrate and the semiconductor element installed to the substrate, and the bonding article of the inspection target may be the wire.

Effects of Invention

According to the invention, a defect of an inspection target can be detected within a short time by using a simple configuration.

DESCRIPTION OF EMBODIMENTS

In the following, a defect detection device100according to an embodiment is described with reference to the drawings. As shown inFIG.1, the defect detection device100is formed by a stage19, ultrasonic wave phased arrays21,22, cameras41,42, a control part50, and an ultrasonic wave phased array controller55. In the following description, the defect detection device100performs defect detection on a semiconductor device10. However, it is possible to perform defect detection on another product. Also, in the following, the description is made by setting the right side ofFIG.1as Y direction, a direction orthogonal to Y direction on a horizontal surface as X direction, and an upper-lower direction as Z direction. In addition, the description is made by setting the direction on the negative side of Y direction as the left side, the positive side of Y direction opposite thereto as the right side, the positive side of X direction as the front side, the negative side of X direction as the rear side, the positive side of Z direction as the upper side, and the negative side of Z direction as the lower side.

In the stage19, a semiconductor device10, which is the inspection target, is sucked and fixed to an upper surface19a. The upper surface19ais a horizontal surface. InFIG.2, an example of the semiconductor device10is shown. In the semiconductor device10shown inFIG.2, a semiconductor element12is installed onto the top of a substrate11, and an electrode14of the semiconductor element12and an electrode15of the substrate11are connected by a wire13such as a gold wire. Here, the substrate11and the semiconductor element11installed to the substrate11are bonded articles bonded by the wire13, and the wire13is a bonding article bonded to the electrode15of the substrate11and the electrode14of the semiconductor element12.

As shown inFIG.1, the cameras41,42as image capturing devices are disposed at the top on the positive side of Z direction on the two sides of the stage19. The respective cameras41,42respectively capture two-dimensional images of the semiconductor device10from the upper side of the semiconductor device10, and output the data of the captured two-dimensional images to the control part50.

The control part50is a computer including therein a CPU51performing information processing, and a memory storing image data input from the cameras41,42. The control part50processes the data of the two-dimensional images of the semiconductor device10input from the cameras41,42to detect the defect of the semiconductor device10. When detecting a defect, the control part50outputs a defect detection signal to the outside.

The ultrasonic wave phased arrays21,22as ultrasonic wave generators are disposed on two sides of the stage19. The ultrasonic wave phased arrays21,22are devices in which multiple, such as tens or hundreds of ultrasonic wave vibrators23are arranged in a plane-like arrangement. When controlling a driving phase so that the phases from all the ultrasonic wave vibrators23are equal at one point in a space, the ultrasonic wave phased arrays21,22can form ultrasonic beams focusing on such point, as indicated by two-dot chain lines36,37shown inFIG.1. In a focus region35focused by the ultrasonic beams, by adding up the amplitudes of the ultrasonic waves from the respective vibrators, ultrasonic waves with a large amplitude are obtained.

The ultrasonic wave phased array21on the right side of the stage19is disposed so that an ultrasonic wave generation surface21aon which the ultrasonic wave vibrators23are disposed is vertical and directed toward the negative side of Y direction, and generates ultrasonic waves traveling toward the negative side of Y direction along the upper surface19aof the stage19. Meanwhile, the ultrasonic wave phased array22on the left side of the stage19is disposed so that an ultrasonic wave generation surface22aon which the ultrasonic wave vibrators23are disposed is vertical and directed toward the positive side of Y direction, and generates ultrasonic waves traveling toward the positive side of Y direction along the upper surface19aof the stage19. In this way, the set of ultrasonic wave phased arrays21,22disposed so that the ultrasonic wave generation surfaces21a,22aface each other respectively generate ultrasonic waves whose traveling directions are different from the respective ultrasonic wave phased arrays21,22, and synthesize the ultrasonic waves, thereby generating a standing wave30between the two ultrasonic wave phased arrays21,22. Accordingly, the set of ultrasonic wave phased arrays21,22form a standing wave generator20synthesizing the ultrasonic waves whose traveling directions are different to generate the standing wave30.

The standing wave30is an ultrasonic wave in which the position of maximum vibration and the position of minimum vibration do not move spatially between the two ultrasonic wave phased arrays21,22. The point where the vibration is the largest is referred to as an antinode33of a sound pressure, and the point where the vibration is the smallest is referred to as a node31of the sound pressure. A distance between adjacent nodes31is ½ of a wavelength λ of the ultrasonic waves generated by the ultrasonic wave phased arrays21,22. In the defect detection device100of the embodiment, the two ultrasonic wave phased arrays21,22are installed at a height so that, as shown inFIG.1, the focus region35, the node31of the sound pressure are right above the semiconductor device10.

The ultrasonic wave phased arrays21,22are connected to the ultrasonic wave phased array controller55. The ultrasonic wave phased array controller55includes therein a CPU56performing information processing and a memory57storing data such as a control program. Based on a command from the control part55, the ultrasonic wave phased array controller55adjusts the vibration speed, the amplitude, and the phase of each of the ultrasonic wave vibrators23of each of the ultrasonic wave phased arrays21,22.

When the frequency of the ultrasonic wave generated by each of the ultrasonic wave vibrators23is adjusted, the interval of the node31of the sound pressure of the standing wave30can be adjusted. In addition, by adjusting the amplitude and the phase of the ultrasonic wave generated by each of the ultrasonic wave vibrators23, the position and the size of the focus region35as shown inFIG.3can be adjusted. For example, by adjusting the amplitude and the phase of the ultrasonic wave generated by each of the ultrasonic wave vibrators23, the shape of the ultrasonic beam is changed from the shape indicated by broken lines36a.37ato the shape indicated by the two-dot chain lines36,37as indicated by arrows91,92, and the position of the focus region35in Z direction can be moved from a focus region35ain the vicinity of the center of the ultrasonic wave phased arrays21,22in Z direction to the position right above the semiconductor device10like the focus region35indicated by the two-dot chain line.

In the defect detection device100of the embodiment, before defect detection starts, it may also be that the amplitude and the phase of the ultrasonic wave generated by each of the ultrasonic wave vibrators23are changed in accordance with the size of the inspection target by using the ultrasonic wave phased array controller55, so as to adjust the amplitude and the phase so that the focus region35, the node31of the sound pressure of the standing wave30is right above the semiconductor device10that is the inspection target, as indicated by the two-dot chain lines shown inFIGS.1and3. In addition, at the same time, the frequency of the ultrasonic wave generated by the ultrasonic wave vibrator23is adjusted in accordance with the detection target to set to a frequency suitable for the detection target. The frequency, for example, may be freely set between 50 kHz to 1 MHz.

Then, the suction force of the node31of the sound pressure of the standing wave30is described with reference toFIG.4. As shown inFIG.4, in the case where density is sufficiently greater than air and the compression rate is sufficiently smaller than air, a particle of a volume (m3) in the standing wave30receives a force F (N) as described above from the sound field of the standing wave30.

Here, U(J/m3) represents a potential distribution, and the particle receives the force F toward where the potential is low. Ka(J/m3) represents the kinetic energy density of the sound field, and Pa(J/m3) represents the potential energy density of the sound field. In addition. < . . . > represents time average.

In the standing wave30, at the position of the node31of the sound pressure (that is, the antinode of particle velocity), the potential is the minimum. Therefore, as shown inFIG.4, the force F toward the node31of the sound pressure is applied to the particle, and the particle is sucked to the node31of the sound pressure. The force F is a sum of the force toward the node31in Y direction and the force toward the node31in X direction and Z direction. Therefore, the node31of the standing wave30sucks the particle toward the node31in Y direction, and sucks the particle toward the node31in X direction and Z direction.

Then, with reference toFIGS.5to7, a process for detecting a connection defect of the wire13of the semiconductor device10by using the defect detection device100according to the embodiment is described.

As shown in Step S101ofFIG.5, the control part50initially performs a focus region adjustment process for changing the amplitude and the phase of the ultrasonic wave generated by each of the ultrasonic wave vibrators23by using the ultrasonic wave phased array controller55in accordance with the size of the inspection target, and adjusting and setting the amplitude and the phase so that the focus region35of the standing wave30is right above the semiconductor device10as the inspection target. At this time, the control part50may change the amplitude and the phase of the ultrasonic wave generated by each of the ultrasonic wave vibrators23by using the ultrasonic phased array controller55based on a sound pressure level detected by a sound pressure sensor or a microphone (not shown) that detects the sound pressure level and is mounted to the position right above of the semiconductor device10, and adjust and set the amplitude and the phase to an amplitude and a phase at which the sound pressure level falls within a predetermined threshold. In addition, the control part50obtains the sound pressure level by using the sound pressure sensor or the microphone to adjust the frequency of the ultrasonic wave generated by the ultrasonic wave vibrator23in accordance with the detection target, and sets the frequency to a frequency suitable for the detection target. When the focus region35is set to the position right above the semiconductor device10through the focus region adjustment process, the position of the node31of the sound pressure located in the focus region35is also at the position right above the semiconductor device10.

In the focus region adjustment process, for example, it may also be that, by keeping fine polystyrene particles at the node31of the sound pressure in the focus region35, the focus region35is visualized, and the position of the focus region35is manually adjusted.

It is noted that the position adjustment process may also be performed manually, so that relative positions of the two ultrasonic wave phased arrays21,22to the semiconductor device10are adjusted in accordance with the size of the inspection target, and the position of the node31of the sound pressure is right above the semiconductor device10. In the position adjustment process, if the relative height of the two ultrasonic wave phased arrays21,22relative to the semiconductor device10can be changed, for example, it may be that the stage19sucking and fixing the semiconductor device10is moved in Z direction, and it may also be that the two ultrasonic wave phased arrays21,22are moved in Z direction.

When the focus region adjustment process ends, the control part50proceeds to Step S102ofFIG.5, and obtains two-dimensional static images61,61(seeFIGS.8and9) of the wire13of the semiconductor device10by using the cameras41,42before the standing wave30is applied to the semiconductor device10, and stores the two-dimensional static images61,62obtained in Step S103ofFIG.5in the memory52(static image capturing process). As shown inFIG.1, the cameras41,42are installed above the two sides of the stage19. Therefore, as shown inFIGS.8and9, the two-dimensional static image61captured by the camera41and the two-dimensional static image62captured by the camera42are different images.

Then, as indicated in Step S104ofFIG.5, the control part50drives the two ultrasonic wave phased arrays21,22to generate the standing wave30, and applies the standing wave30to the semiconductor device10.

When the ultrasonic wave phased arrays21,22are driven to generate the standing wave30, as shown inFIG.6, multiple nodes31of the sound pressure in the standing wave30are present side-by-side at the position right above the wire13of the semiconductor device10, and the focus region35is present right above the substrate11, the semiconductor element12of the semiconductor device10. As described above, the sound wave is enhanced in the focus region35or the periphery thereof, and the suction force of the node31of the sound pressure is increased.

Therefore, the substrate11, the semiconductor element12, and the wire13are applied with a suction force sucking toward the node31of the sound pressure and are sucked upward. Here, the substrate11is sucked and fixed to the upper surface19aof the stage19, and the semiconductor element12is bonded onto the substrate11. Therefore, the substrate11and the semiconductor element12are not sucked up by the node31of the sound pressure.

In the case where the bonding between a stitch bond part18of the wire13and the electrode15of the substrate11is defective and a small gap or crack is present, or in the case where the stitch bond part18of the wire13and the electrode15of the substrate11are merely in contact but not bonded to each other, as shown inFIG.6, the stitch bond part18of the wire13is sucked upward by the upward suction force of the node31of the sound pressure as indicated by a hatched arrow95inFIG.6, and is deformed upward as in a stitch bond part18a. Meanwhile, in the case where the bonding between the wire13and the electrode14is favorable like that between a ball bond part16and the electrode14of the semiconductor element12, the wire13does not deform.

Comparatively, in the case where the bonding between the stitch bond part18and the electrode15of the substrate11is favorable, and a crack occurs in a ball neck part17on the upper side of the ball bond16, as shown inFIG.7, the ball neck part17of the wire13is sucked upward by the suction force of the node31of the sound pressure, and is deformed upward as in a ball neck part17a.

Therefore, in the state in which the standing wave30generated by the two ultrasonic wave phased arrays21,22is applied to the semiconductor device10, as shown in Step S105ofFIG.5, the control part50captures two-dimensional suction images71,72(seeFIGS.11,12) of the wire13of the semiconductor device10by using the cameras41,42, and stores the two-dimensional images71,72in the memory52in Step S106(suction image capturing process). Like the two-dimensional static images61,62described above, since the cameras41,42are installed above the two sides of the stage19, the two-dimensional suction image71captured by the camera41and the two-dimensional suction image72captured by the camera42are different images.

In Step S107ofFIG.5, the control part50reads the two-dimensional static images61,62respectively captured by the two cameras41,42from the memory52, and, as shown inFIG.10, generates a three-dimensional static image63of the wire13of the semiconductor device10before the standing wave30is applied. Similarly, the control part50reads the two-dimensional suction images71,72of the wire13respectively captured by the two cameras41,42from the memory52, and, as shown inFIG.13, generates a three-dimensional suction image73of the wire13of the semiconductor device10in the state in which the standing wave30is applied. Here, the three-dimensional static image63and the three-dimensional suction image73are generated to favorably detect a difference between the images of the wire13before and after deformation even if the wire13deforms in the upper direction, as shown inFIGS.6and7.

Then, in Step S108ofFIG.5, the control part50compares the three-dimensional static image63and the three-dimensional suction image73that are generated. As described above with reference toFIG.6, in the case where there is no bonding defect in the wire13, the wire13does not deform, and in the case where there is a bonding defect in the wire13, the wire13deforms. Therefore, as shown in Step S107ofFIG.5, the control part50compares the three-dimensional static image63before the standing wave30is applied and the three-dimensional suction image73in or after the state in which the standing wave30is applied, and calculates a differential Δd therebetween for each portion, as shown inFIG.13.FIG.13shows, as an example, differentials Δd1and Δd2at two portions P1, P2in the vicinity of the stitch bond part18of the wire13. At this time, the control part50calculates the differential Δd of each portion for all of the multiple wires13of the semiconductor device10as shown inFIG.2.

Then, in Step S109ofFIG.6, the control part50determines whether there is a portion in which the differential Δd is greater than a threshold ΔS, and, in the case where the differential Δd is greater than the threshold ΔS, determines that it is YES in Step S109ofFIG.6and proceeds to Step S110ofFIG.6to output a wire defect detection signal to the outside. In addition, in the case where the control part50determines that it is NO in Step S109ofFIG.6, the control part50proceeds to Step S111ofFIG.6and outputs a wire favorable signal to the outside (defect detection process).

Here, the wire defect detection signal is a signal indicating that a bonding defect occurs in at least one of the wires13of the semiconductor device10shown inFIG.2, and the wire favorable signal is a signal indicating that the bonding of all of the wires13of the semiconductor device10shown inFIG.2is favorable.

As described above, after capturing the two-dimensional static images61,62of the semiconductor device10before the standing wave30is applied by using the cameras41,42, the defect detection device10of the embodiment applies the standing wave30generated by the set of ultrasonic wave phased arrays21,22to the semiconductor device30, sucks the portion of the bonding defect of the wire13upward by the node31of the sound pressure of the standing wave30, captures the two-dimensional suction images71,72of the semiconductor device10including the deformed wire13by using the cameras41,42, generates the three-dimensional static image63and the three-dimensional suction image73, and detects the defect of the wires13by comparing the three-dimensional static image63and the three-dimensional suction image73that are generated. In this way, the defect detection device100of the embodiment can detect a defect of the wires13within a short time by using a simple configuration.

The two-dimensional suction images71,72and the three-dimensional suction image73as described above are first images of the semiconductor device10in a first state in which the suction force is applied to the wire13, and the two-dimensional static images61,62and the three-dimensional static image63are images of a second state in which the suction force is smaller than that of the first state. Moreover, the suction image capturing process is a first image capturing process, and the static image capturing process is a second image capturing process.

Although the above description is made by describing that the three-dimensional static image63and the three-dimensional suction image73are compared to perform defect detection, the invention is not limited thereto. For example, it may also be that the two-dimensional static images61,62and the two-dimensional suction images71,72captured by the cameras41,42are compared to detect the defect of the wire13.

In addition, although the above description is made by describing that whether a bonding defect occurs in at least one of the wires13or the bonding of all of the wires13is favorable is determined, the invention is not limited thereto. It may also be that a position where the differential Δd is equal to or greater than the threshold ΔS is specified and displayed as a defect position on the image of the semiconductor device10.

Moreover, although in the defect detection device100described above, the ultrasonic wave phased arrays21,22in which tens or hundreds of the ultrasonic wave vibrators23are arranged in a plane-like arrangement, the invention is not limited thereto. For example, it may also be configured that the ultrasonic wave phased arrays21,22are configured by disposing multiple ultrasonic wave speakers in a plane-like arrangement.

Moreover, the standing wave generator20generating the standing wave30may also be configured by using ultrasonic wave speakers as ultrasonic wave generators in place of the ultrasonic phased arrays21,22and disposing the ultrasonic wave speakers to face each other.

In the following, a defect detection device200according to another embodiment is described with reference toFIG.14. In place of the standing wave generator20formed by the two ultrasonic wave phased arrays21,22of the defect detection device100described above with reference toFIGS.1to13, the defect detection device200is formed with a standing wave generator25which generates the standing wave30by using one ultrasonic wave phased array21and a reflective plate24disposed on the left side of the stage19to face the ultrasonic wave phased array21. The rest are the same as the defect detection device100described above. Therefore, like components are labeled with like reference symbols and the description thereof is omitted.

Here, the reflective plate24may be made from metal or formed from resin or glass, as long as the reflective plate24has a reflective surface24areflecting ultrasonic waves. In addition, the reflective surface24areflecting ultrasonic waves is not particularly limited as long as the reflective surface24ais a smooth flat surface capable of reflecting ultrasonic waves.

In the following, a defect detection device300according to another embodiment is described with reference toFIGS.15to18. As shown inFIG.15, the ultrasonic wave phased array21of the defect detection device300is disposed so that the ultrasonic wave generation surface21afaces the upper surface19aof the stage19above the stage19. In addition, the defect detection device300is configured so that the ultrasonic waves generated by the ultrasonic wave phased array21are reflected by the surface11aof the substrate11of the semiconductor device10sucked and fixed onto the stage19, and the standing wave30is generated between the ultrasonic wave phased array21and the surface11aof the substrate11of the semiconductor device10. The surface11aof the substrate11is configured as the reflective surface reflecting ultrasonic waves, and the ultrasonic wave phased array21and the surface11aof the substrate11form a standing wave generator26generating the standing wave30. In the defect detection device300, the ultrasonic wave phased array21is disposed above the stage19, so the defect detection device300can be disposed in a smaller configuration space.

In the defect detection device300shown inFIG.15, the frequency of the ultrasonic waves generated by the ultrasonic wave phased array21is adjusted so that the node31of the sound pressure of the standing wave30is right above the semiconductor device10. As shown inFIG.15, the node31of the sound pressure of the standing wave30is generated at a height of λ/2 that is a half of the wavelength λ of the ultrasonic wave from the surface11aof the substrate11. In the case where the height from the surface11aof the substrate11to the uppermost part of the wire13is h, the frequency is set so that λ/2 is slightly greater than h. For example, in the case where the height h of the wire13is 500 (μm), the frequency is set to 200 to 300 (kHz).

As shown inFIG.16, in the defect detection device300, the focus region35is generated at a height that is in the middle between the ultrasonic wave phased array21and the surface11aof the substrate11and slightly closer to the substrate11. As described above with reference toFIG.3, by adjusting the amplitude and the phase of each of the ultrasonic wave vibrators23of the ultrasonic wave phased array21, the focus region35can be moved in XY direction along the upper surface19aof the stage19. For example, as shown inFIG.16, by adjusting the amplitude and the phase of the ultrasonic wave generated by each of the ultrasonic wave vibrators23, the shape of the ultrasonic beam is changed from the shape indicated by the broken lines36a.37ato the shape indicated by the two-dot chain lines36,37as indicated by arrows93,94, and the position of the focus region35in Z direction can be moved in Y direction from the focus region35aright above the semiconductor element12as indicated by the broken line to a position right above the wire13as the focus region35indicated by the two-dot chain line. Accordingly, the center of the standing wave30can be moved to the vicinity of the wire13that is an inspection target component.

Then, with reference toFIGS.17to18, a process for detecting a bonding defect of the wire13by using the defect detection device300is described. The description regarding an operation same as the operation of the defect detection device100described above is omitted.

The control part50adjusts the frequency of the ultrasonic wave generated by the ultrasonic wave phased array21so that initially the position of the node31of the sound pressure of the standing wave30is located right above the wire13. In addition, in accordance with the configuration of the semiconductor device10, the amplitude and the frequency of each of the ultrasonic wave vibrators23of the ultrasonic wave phased array21are adjusted to adjust the position of the focus region35in XY direction (focus region position adjustment process).

As shown inFIG.17, when the standing wave30is applied to the wire13of the semiconductor device10, the node31of the sound pressure is generated at a position at the height of λ/2 from the substrate11. As described above, the frequency of the ultrasonic wave generated by the ultrasonic wave phased array21is adjusted, so that the position of the node31of the sound pressure is slightly greater than the height to the uppermost part of the wire13. Therefore, as shown inFIG.17, the node31of the sound pressure is generated slightly upper of the wire13. As indicated by a hatched arrow98inFIG.17, the node31of the sound pressure applies a force toward the node31of the sound pressure to particles in the periphery.

In addition, in the defect detection device300, the ultrasonic wave generated by the ultrasonic wave phased array21is reflected by the surface11aof the substrate11to generate the standing wave30. Therefore, a node32of the sound pressure is also generated on the surface11aof the substrate11reflecting the ultrasonic wave generated by the ultrasonic wave phased array21. As indicated by a hatched arrow99inFIG.17, the node32of the sound pressure applies a force toward the node32of the sound pressure to particles in the periphery.

The node31of the sound pressure sucks the wire13upward to apply an upward pulling force to the wire13. Meanwhile, the node32of the sound pressure sucks the wire13downward to apply a downward pulling force to the wire13. However, the suction force generated at the node32of the sound pressure is much smaller than the suction force generated at the node31of the sound pressure. Therefore, the wire13is sucked in the upper direction toward the node31of the sound pressure. In the case where the bonding between the stitch bond part18of the wire13and the electrode15of the substrate11is defective, the stitch bond part18of the wire13becomes the deformed stitch bond part18athat deforms upward.

Similarly, in the case where there is a crack at the ball neck part17as shown inFIG.18, the ball neck part17of the wire13is sucked upward by the suction force of the node31of the sound pressure, and is deformed upward like the ball neck part17a.

Therefore, like the defect detection device100, after capturing the two-dimensional static images61,62of the wire13of the semiconductor device10by using the cameras41,42before the standing wave30is applied, the defect detection device300applies the standing wave30to the semiconductor device10, sucks the portion of the bonding defect of the wire13upward by using the standing wave30, captures the two-dimensional suction images71,72of the semiconductor device10including the deformed wire13by using the cameras41,42, generates the three-dimensional static image63and the three-dimensional suction image73, and detects the defect of the wires13by comparing the three-dimensional static image63and the three-dimensional suction image73that are generated. In this way, the defect detection device300of the embodiment can detect a defect of the wires13within a short time by using a simple configuration.

When the defect detection device300performs defect detection on the wire13, it may also be that the amplitude and the phase of each of the ultrasonic wave vibrators23of the ultrasonic wave phased array21are adjusted to move the position of the focus region35in XY direction while capturing the two-dimensional suction images71,72. Accordingly, since the two-dimensional suction images71,72are captured in the state in which the region where the standing wave30is strong is located above the wire13, the deformation of the wire13can be increased, and the accuracy of defect detection on the wire13can be increased.

In addition, when the defect detection device300performs defect detection on the wire13, it may also be that the position of the focus region35in XY direction is moved in accordance with the size and the shape of the inspection target while capturing the two-dimensional suction images71,72. Accordingly, even in the case where the inspection target is large or the shape is complicated, the defect of the entire inspection target can be more accurately detected without moving the ultrasonic phased array21or the stage19.

In the above description, the two-dimensional static images61,62are captured before the standing wave30is applied to the semiconductor device10, and then the two-dimensional suction images71,72of the semiconductor device10are captured in the state in which the standing wave30is applied. However, the invention is not limited thereto. For example, in the case where, after the standing wave30is applied to the wire13or when the standing wave30is stopped, the deformation of the wire13returns to the original state or a state close to the original state, for example, it may also be that the two-dimensional suction images71,72of the semiconductor device10in the state in which the standing wave30is applied to the semiconductor device10are captured, and then the two-dimensional static images61,62are captured after the standing wave30is stopped. In addition, in the case where there is a correlation between the deformation of the wire13and the output of the ultrasonic wave phased arrays21,22, in place of the two-dimensional static images61,62, two-dimensional low suction images in a second state that is a low suction force state where the output of the ultrasonic wave phased arrays21,22is smaller than the first state are captured, and the two-dimensional low suction images are compared with the two-dimensional suction images71,72of the first state to perform defect detection. Moreover, it may also be that a three-dimensional low suction image is generated from the two-dimensional low suction images, and the three-dimensional low suction image is compared with the three-dimensional suction image73to perform defect detection.

REFERENCE SIGNS LIST