CN116325102A

CN116325102A - Wire bonding apparatus, method for controlling wire bonding apparatus, and program for controlling wire bonding apparatus

Info

Publication number: CN116325102A
Application number: CN202180069920.7A
Authority: CN
Inventors: 笠间広幸; 早田滋
Original assignee: Shinkawa Ltd
Current assignee: Shinkawa Ltd
Priority date: 2021-01-26
Filing date: 2021-01-26
Publication date: 2023-06-23
Also published as: TW202230555A; JPWO2022162716A1; WO2022162716A1; KR20230133342A; TWI817330B

Abstract

The invention provides a wire bonding apparatus, which can prevent bonding under the condition of no air ball eccentric core. The wire bonding apparatus includes: a porcelain nozzle for supplying the bonding wire; a gas torch forming a free air ball for the wire tail of the bonding wire extending from the porcelain nozzle; an imaging unit for imaging a wire tail in a state where an air balloon is formed at a tip portion thereof by a torch; and a measuring unit that measures the displacement of the free air ball with respect to the center axis of the joint line based on the image output from the imaging unit.

Description

Wire bonding apparatus, method for controlling wire bonding apparatus, and program for controlling wire bonding apparatus

Technical Field

The present invention relates to a wire bonding (wire bonding) device, a method of controlling the wire bonding device, and a program for controlling the wire bonding device.

Background

In a wire bonding apparatus, it is important to stabilize the shape of a Free Air Ball (FAB). For example, according to patent document 1, a stable FAB is formed by studying the composition of bonding wires.

Prior art literature

Patent literature

Patent document 1: japanese patent No. 5807992

Disclosure of Invention

Problems to be solved by the invention

Bonding wires used in wire bonding apparatuses are various, and are often used in various ways depending on the purpose. Therefore, the availability of bonding wires of specific compositions is a major limitation. In addition, not limited to the composition, factors such as ambient temperature, wire diameter, wire tail length, etc. may also affect the misalignment of the airless ball with respect to the wire axis. The core shift of the free air ball may cause the core shift of the press-fit ball, and may cause defects such as short circuit between the cushion electrodes.

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a wire bonding apparatus and the like capable of preventing bonding from being performed without air ball misalignment.

Technical means for solving the problems

The wire bonding apparatus according to the first aspect of the present invention includes: a porcelain nozzle for supplying the bonding wire; a torch (torch) forming a free air ball for a wire tail (wire tail) of a bonding wire extending from the tip; an imaging unit for imaging a wire tail in a state where an air balloon is formed at a tip portion thereof by a torch; and a measuring unit that measures the displacement of the free air ball with respect to the center axis of the joint line based on the image output from the imaging unit.

The control method of the wire bonding apparatus according to the second aspect of the present invention includes: a wire tail forming step of forming a wire tail by extending the bonding wire from the front end of the porcelain nozzle; an airless ball forming step of forming an airless ball at the front end of the wire tail using a torch; an imaging step of imaging a wire tail formed with or without an air balloon; and a measurement step of measuring the displacement of the airless ball with respect to the center axis of the bonding wire based on the image output in the imaging step.

A control program of a wire bonding apparatus according to a third aspect of the present invention causes a computer to execute: a wire tail forming step of forming a wire tail by extending the bonding wire from the front end of the porcelain nozzle; an airless ball forming step of forming an airless ball at the front end of the wire tail using a torch; an imaging step of imaging a wire tail formed with or without an air balloon; and a measurement step of measuring the displacement of the airless ball with respect to the center axis of the bonding wire based on the image output in the imaging step.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the wire bonding apparatus and the like of the present invention, it is possible to form an airless ball in a manufacturing environment where a semiconductor chip is actually manufactured and immediately measure the core misalignment state thereof, and thus it is possible to prevent bonding from being performed in the airless ball core misalignment state.

Drawings

Fig. 1 is a perspective view schematically showing an essential part of a wire bonding machine (wire bonding) according to the present embodiment.

Fig. 2 is a system configuration diagram of the wire bonding machine.

Fig. 3 is a diagram illustrating the observation state of the FAB.

Fig. 4 is a diagram illustrating a first method of measuring an offset of a FAB.

Fig. 5 is a diagram illustrating a second method of measuring an offset of a FAB.

Fig. 6 is a flowchart illustrating a processing sequence of the first example including the FAB measurement of the present embodiment.

Fig. 7 is a flowchart illustrating a processing sequence of the second example including the FAB measurement of the present embodiment.

Fig. 8 is a flowchart illustrating a processing sequence of the third example including the FAB measurement of the present embodiment.

Fig. 9 is a perspective view schematically showing an essential part of a wire bonding machine according to another embodiment.

Detailed Description

The present invention will be described below with reference to the following embodiments, but the invention described in the claims is not limited to the following embodiments. In addition, all the structures described in the embodiments are not necessarily required as means for solving the problems.

Fig. 1 is a perspective view schematically showing an essential part of a wire bonding machine 100 according to the present embodiment. The illustrated wire bonding machine 100 uses a simplified structure or mechanism for understanding, or makes the sizes or shapes of the members different, or omits the members that are not directly related to the present embodiment, but is not intended to represent the differences from the actual wire bonding machine.

The wire bonding machine 100 is a bonding device that connects a pad electrode (pad electrode) 321 of a semiconductor chip 320 and a lead electrode (lead electrode) 322 of a substrate 330 by a wire 300 as a bonding wire. The wire bonding machine 100 mainly includes a head 110, a tool part 120, a torch 131, a porcelain nozzle 133, a first imaging unit 151, and a second imaging unit 152. The head 110 supports the tool 120, the torch 131, the first imaging unit 151, and the second imaging unit 152, and is movable in the planar direction by a head drive motor 141. The plane direction is a horizontal direction defined by the X-axis direction and the Y-axis direction as shown in the figure, and is also a moving direction of the stage 220 mounted on the stage 210. A substrate 330 is mounted and fixed on the stage 220.

The tool portion 120 supports a clip (clamp) 132 and a transducer 134 extending in the Y-axis direction, and a porcelain nozzle 133 is disposed at the tip end of the transducer 134. The wire clamp 132 has a hand (hand) for holding the wire 300, and clamps and releases the wire 300 under the control of the wire bonding machine 100. The transducer 134 gives ultrasonic vibration to the vicinity of the front end of the lead 300 via the porcelain nozzle 133 at the time of bonding. The porcelain nozzle 133 functions as follows: the lead 300 is supplied to the pad electrode 321 and the lead electrode 322 by being guided, and the tip portion presses the lead 300 against the pad electrode 321 and the lead electrode 322 at the time of bonding. The wire 300 is supplied from a wire supply unit (not shown) including a tensioner (tensioner) or a rotating spool. The material of the lead 300 is appropriately selected according to the kind or property of the semiconductor chip 320, and gold, silver, copper, for example, are used.

The torch 131 is supported by the head 110 and includes a discharge electrode at a front end portion. At the time of first bonding (first bond) to the pad electrode 321, a lead 300 of a certain length is projected from the front end portion of the porcelain nozzle 133 to form a wire tail. In this state, the tip of the wire tail faces the electrode of the torch 131 along the X-axis direction, and as shown in the figure, a voltage is applied to the electrode to form an airless Ball (FAB) 301 in a molten state. The tool portion 120 is movable in the height direction with respect to the head portion 110 by a tool driving motor 142, and the tip end portion of the wire tail can be made to face the electrode of the torch 131, or can be made to approach or separate from the pad electrode 321 or the wire electrode 322. The height direction is shown as the Z-axis direction orthogonal to the planar direction.

The first imaging unit 151 is an imaging unit for imaging the FAB 301 formed at the tip end portion of the wire tail from the Y-axis direction, and is supported by the head 110. The first imaging unit 151 includes: an image pickup element that outputs an image signal; and an optical system for imaging an image of the FAB 301 on the imaging element. The second imaging unit 152 is an imaging unit for imaging the FAB 301 formed at the tip end portion of the wire tail from the X-axis direction, and is supported by the head 110 in the same manner as the first imaging unit 151. The second image capturing unit 152 also includes: an image pickup element that outputs an image signal; and an optical system for imaging an image of the FAB 301 on the imaging element. In the following description, the first imaging unit 151 and the second imaging unit 152 may be collectively referred to as an imaging unit.

The XYZ coordinate system is a spatial coordinate system having the reference position of the head 110 as the origin. In the drawings below, the same coordinate axes may be collectively described for the purpose of indicating the directions of the respective members.

Fig. 2 is a system configuration diagram of the wire bonding machine 100. The control system of the wire bonding machine 100 mainly includes an arithmetic processing unit 170, a storage unit 180, an input/output device 190, a torch 131, a wire clamp 132, a converter 134, a head driving motor 141, a tool driving motor 142, a first imaging unit 151, and a second imaging unit 152. The arithmetic processing unit 170 is a processor (central processing unit (Central Processing Unit, CPU)) that performs control and execution processing of a program of the wire bonding machine 100. The processor may also be a structure that cooperates with an arithmetic processing chip such as an application specific integrated circuit (Application Specific Integrated Circuit, ASIC) or a graphics processor (Graphics Processing Unit, GPU). The arithmetic processing unit 170 reads the control program stored in the storage unit 180, and executes various processes related to the joining.

The storage unit 180 is a nonvolatile storage medium, and includes, for example, a Hard Disk Drive (HDD). The storage unit 180 may store various parameter values, functions, look-up tables (look-up tables), and the like for control or operation, in addition to a program for executing control or processing of the wire bonding machine 100. The input/output device 190 includes, for example, a keyboard, a mouse, and a display monitor, and is a device for receiving a menu operation performed by a user or presenting information to the user. For example, the arithmetic processing unit 170 may display the measurement result of the FAB together with the captured image on a display monitor which is one of the input/output devices 190.

When receiving the discharge instruction signal from the arithmetic processing unit 170, the torch 131 performs voltage application to the electrode. When voltage application to the electrode is performed, arc discharge is generated between the electrode and the wire tail, and a FAB is formed at the tip end of the wire tail. The wire clamp 132 closes the hand during the period when the clamp instruction signal is received from the operation processing unit 170. When the clamping instruction signal is released, the hand is opened. The lead 300 does not protrude from the beak 133 or pull back toward the beak 133 during the period of hand closure. When receiving the excitation signal from the operation processing unit 170, the transducer 134 vibrates the vibrator. The ultrasonic vibrations caused by transducer 134 facilitate bonding of wire 300.

The head drive monitor 141 receives the drive signal from the arithmetic processing unit 170, and moves the head 110 in the planar direction. The tool driving motor 142 receives a driving signal from the arithmetic processing unit 170, and moves the tool unit 120 in the height direction.

The first imaging unit 151 receives the imaging request signal from the arithmetic processing unit 170, performs imaging, and transmits the first image output from the imaging element to the arithmetic processing unit 170 as an image signal. Similarly, the second image pickup unit 152 receives the image pickup request signal from the arithmetic processing unit 170, performs image pickup, and transmits the second image output from the image pickup device to the arithmetic processing unit 170 as an image signal.

The arithmetic processing unit 170 also plays a role as a function arithmetic unit, and executes various operations according to the processing instructed by the control program. The arithmetic processing unit 170 functions as a measuring unit 171, an adjusting unit 172, and a drive control unit 173. The measurement unit 171 transmits an imaging request signal to the first imaging unit 151 and the second imaging unit 152, acquires an image signal of the first image and an image signal of the second image, and measures the shift of the FAB with respect to the center axis of the lead 300. The adjustment unit 172 adjusts the discharge condition of the torch 131 based on the measurement result obtained by the measurement unit 171. The drive control unit 173 generates a drive signal for driving the head drive motor 141 and a drive signal for driving the tool drive motor 142, and transmits the signals to the motors.

Fig. 3 is a diagram illustrating the observation state of the FAB. As described above, the lead 300 is extended from the tip end of the tip 133 to form a tail, and the tip end of the tail is subjected to arc discharge of the torch 131 from the X-axis positive direction to form the FAB 301.

Depending on the discharge conditions of the torch 131, the FAB 301 may be formed offset from the central axis of the lead 300. If the amount of displacement exceeds the allowable amount, the core of the press-fit ball formed on the pad electrode 321 during the first bonding is displaced, resulting in defects such as short-circuiting between the pad electrodes 321. The deflection of FAB 301 is caused by the composition or diameter of wire 300, the wire tail length, the ambient temperature, and other factors. Therefore, it is preferable to form the FAB 301 under the condition that the wiring operation is actually performed, and evaluate whether or not the offset thereof exceeds the allowable amount. In addition, even when the offset amount exceeds the allowable amount, the discharge condition of the torch 131 may be adjusted so as to be suppressed to or below the allowable amount. Therefore, the wire bonding machine 100 of the present embodiment photographs the actually formed FAB 301 and measures its offset.

The first imaging unit 151 is provided so as to capture the line tail including the FAB 301 from the Y-axis direction, that is, the direction orthogonal to the Z-axis direction, which is the extending direction from the porcelain nozzle 133 to extend the line tail, and the X-axis direction, which is the discharging direction of the arc discharge. The first imaging unit 151 generates an image signal of a first image obtained by capturing a line tail from the Y-axis direction. In the present embodiment, the first imaging unit 151 is provided so as to capture the line tail from the Y-axis negative direction, but may be provided so as to capture the line tail from the Y-axis positive direction. The shift of the FAB 301 is easily generated in the discharge direction, and therefore the shift thereof can be accurately grasped from the first image taken from the direction orthogonal to the discharge direction.

The second imaging unit 152 is provided so as to capture the line tail including the FAB 301 from the X-axis direction. The second imaging unit 152 generates an image signal of a second image obtained by capturing a line tail from the X-axis direction. In the present embodiment, the second imaging unit 152 is provided to capture the line tail from the negative X-axis direction, but may be provided to capture the line tail from the positive X-axis direction. If the second image is also the object of measurement in addition to the first image, the offset of the FAB 301 can be accurately grasped from two orthogonal directions.

The imaging unit of the present embodiment includes two imaging units, i.e., the first imaging unit 151 and the second imaging unit 152, but the imaging unit may be further added. In this case, the additional imaging unit is preferably provided in such a manner that: the tail may be photographed from a direction orthogonal to the Z axis, which is the extending direction of the extending tail.

The measurement unit 171 measures the shift of the FAB 301 from the acquired image. Here, two measurement methods will be described with reference to drawings.

Fig. 4 is a diagram illustrating a first method of measuring an offset of the FAB 301. The measurement unit 171 measures a first protruding amount that is the protruding amount of the FAB 301 in one direction with respect to the central axis direction of the lead 300, and a second protruding amount that is the protruding amount in the other direction opposite to the one direction.

Fig. 4 is a left view showing a first image acquired from the first imaging unit 151. In the first image, the first projection amount is a distance D from the surface of the lead 300 (a boundary line offset from the center axis of the lead 300 by the radius of the lead 300) to the vertex of the X-axis positive side of the FAB 301 ₁ . Similarly, the second protruding amount is a distance D from the surface of the lead 300 (a boundary line offset from the center axis direction X-axis negative side of the lead 300 by the radius of the lead 300) to the vertex of the X-axis negative side of the FAB 301 ₂ . For example, if the core shift evaluation value=1.0 to Min (D ₁ ，D ₂ )/Max(D ₁ ，D ₂ ) In Max (D ₁ ，D ₂ )＝D ₁ When a "-" symbol is given, when Max (D ₁ ，D ₂ )＝D ₂ The "+" sign is given to indicate to which side the offset is to what extent. If D ₁ ＝D ₂ The core shift evaluation value becomes 0, and it is found that there is no shift with respect to the imaging direction of the first image.

The right diagram of fig. 4 shows the second image acquired from the second image pickup unit 152. In the second image, the first projection amount is a distance D from the surface of the lead 300 (a boundary line offset from the center axis of the lead 300 by the radius of the lead 300) to the vertex of the Y-axis negative side of the FAB 301 ₃ . Similarly, the second protruding amount is a distance D from the surface of the lead 300 (a boundary line offset by the radius of the lead 300 with respect to the center axis Y-axis positive side of the lead 300) to the vertex of the Y-axis positive side of the FAB 301 ₄ . Similarly, if the core shift evaluation value=1.0 to Min (D ₃ ，D ₄ )/Max(D ₃ ，D ₄ ) In Max (D ₃ ，D ₄ )＝D ₃ When a "-" symbol is given, when Max (D ₃ ，D ₄ )＝D ₄ The "+" sign is given to indicate to which side the offset is to what extent. If D ₃ ＝D ₄ The core shift evaluation value becomes 0, and it is found that there is no shift with respect to the imaging direction of the second image.

Further, since the diameter of the actual lead 300 inserted into the porcelain nozzle 133 is known, the actual distance of each pixel can be calculated from the width of the lead 300 on the image. This allows the distance (number of pixels) on the image to be converted into the actual distance.

Fig. 5 is a diagram illustrating a second method of measuring the offset of the FAB 301. The measurement unit 171 measures the amount of misalignment of the center of the FAB 301 with respect to the center axis of the lead 300.

Fig. 5 is a left diagram showing a first image acquired from the first imaging unit 151. In the first image, the offset is from the center axis of FAB 301 to the center C of FAB 310 _X Distance D to _X . For example, if the core shift evaluation value=d _X At C _X When the compound is present on the positive side of the X-axis with respect to the center axis, the compound is addedSymbol of C _X When the "+" sign is given to the side of the center axis on the negative side of the X axis, it is possible to indicate to which side the shift is made. If D _X When=0, the core shift evaluation value becomes 0, and it is found that there is no shift with respect to the imaging direction of the first image.

The right diagram of fig. 5 shows the second image acquired from the second image pickup unit 152. In the second image, the offset is from the center axis of FAB 301 to the center C of FAB 310 _Y Distance D to _Y . For example, if the core shift evaluation value=d _Y At C _Y When the Y-axis is located on the negative side of the central axis, a "-" symbol is given to the Y-axis, and C is _Y When the "+" sign is given to the positive side of the Y axis with respect to the center axis, it is possible to indicate to which side the shift is made. If D _Y When=0, the core shift evaluation value becomes 0, and it is found that there is no shift with respect to the imaging direction of the second image. The conversion from the distance (number of pixels) on the image to the actual distance is the same as in the case of fig. 4.

The misalignment measurement of the FAB 310 by the measurement unit 171 can be incorporated into various manufacturing processes that actually perform the interconnect work. Here, 3 embodiments will be described with reference to the drawings.

Fig. 6 is a flowchart illustrating a processing sequence of the first example including the core shift measurement of the FAB of the present embodiment. In the first embodiment, before performing the wire work, in order to determine the discharge condition of the torch 131 in such a manner that the FAB satisfying the criterion is formed, the misalignment measurement of the FAB is performed. The illustrated flow begins, for example, at a ready point in time prior to execution of the join line.

In step S111, the adjustment unit 172 receives an input of an initial setting concerning the discharge condition of the torch 131 via the input/output device 190. The adjustment unit 172 is not limited to the input by the input/output device 190, and may use a predetermined initial setting. In step S112, the drive control unit 173 extends the wire 300 from the wire supply unit, and extends the wire 300 from the tip end of the porcelain nozzle 133 to form a wire tail. At this time, if the tip of the formed wire tail is not opposed to the electrode of the torch 131, the tool drive motor 142 is driven to adjust the height of the wire tail in an opposed manner.

In step S113, the adjustment unit 172 applies a voltage to the electrode of the torch 131 according to the set discharge conditions, and forms the FAB 301 at the tip end of the wire tail. In step S114, the measurement unit 171 transmits an imaging request signal to the first imaging unit 151 and the second imaging unit 152, respectively, and performs imaging processing to acquire a first image and a second image obtained by imaging the line tail including the FAB 301. Then, in step S115, the shift of the FAB 301 with respect to the center axis of the lead 300 is measured from the first image and the second image by using any one of the measurement methods described with reference to fig. 4 and 5. Which measurement method to use may be selected in advance by an operator, or may be automatically selected according to the setting of the semiconductor chip 320 or the like. Alternatively, the control program may be associated with only one of the measurement methods.

In step S116, the measurement unit 171 determines whether or not the measurement result satisfies a preset criterion. The reference is defined as, for example, an allowable amount of the core shift evaluation value that does not cause a defect such as a short circuit between the pad electrodes 321. If the core shift evaluation value as the measurement result exceeds the allowable amount, the process proceeds to step S117. If the discharge conditions are acceptable, it is considered that an appropriate FAB can be formed under the set and adjusted discharge conditions, and a series of preparation operations are terminated until the wiring operation of the semiconductor chip 320 is performed.

When the process advances to step S117, the arithmetic processing unit 170 causes the formed FAB 301 to adhere to a dummy electrode pad or the like, closes the clip 132, and cuts the lead 300. Then, in step S118, the adjustment unit 172 adjusts the discharge condition in consideration of the measurement result obtained by the measurement unit 171. That is, in the case of the core being displaced in a certain direction, the spark current, the current tilting time, the gas flow rate, and the like are changed in consideration of the difference in the cooling rate of the FAB surface, and in the case of the core being displaced in a random direction, the pre-spark delay time and the like are added in consideration of the influence of the vibration, and the parameters of the discharge condition are changed in accordance with the magnitude or direction of the displacement. After completion of the adjustment of the discharge conditions, in order to evaluate the FAB 301 formed by the adjusted discharge conditions, the process returns to step S112, and a series of processes is continued.

If the wire operation of the semiconductor chip 320 is entered through such a preparation operation, the FAB can be stably formed from the initial stage of the wire operation.

Fig. 7 is a flowchart illustrating a processing sequence of the second example including the core shift measurement of the FAB of the present embodiment. In a second embodiment, FAB actually formed during execution of the join line operation is monitored. The illustrated flow starts at the point in time when the wiring operation starts for each semiconductor chip 320 on the substrate 330 provided on the stage 220. In addition, the same processes as those described using fig. 6 are assigned the same process numbers, and thus the description thereof is omitted except for the cases specifically mentioned.

When the flow starts, the steps S111 to S116 execute the same processing as the corresponding steps of fig. 6. However, the FAB 301 formed here is not formed for measurement but actually follows the pad electrode 321 of the semiconductor chip 320.

After determining in step S116 that the criterion is satisfied, the measurement unit 171 proceeds to step S121. The drive control unit 173 applies the first bonding to the target pad electrode 321 by bonding the FAB 301. At this time, the arithmetic processing unit 170 transmits an excitation signal or the like to the converter 134, and executes control associated with the first engagement.

Then, in step S122, the drive control unit 173 moves the lead 300 to the corresponding lead electrode 322, and performs the second bonding. At this time, the arithmetic processing unit 170 transmits an excitation signal or the like to the converter 134, and executes control accompanied with the second engagement. The arithmetic processing unit 170 proceeds to step S123, closes the wire clamp 132, cuts the lead 300, and proceeds to step S124.

In step S124, the arithmetic processing unit 170 checks whether or not all the joining processes have been completed. If not, the process returns to step S112 to execute the remaining bonding process, and a series of processes is continued. If so, a series of joining processes is ended.

If the measurement unit 171 determines in step S116 that the reference is not satisfied, the process proceeds to step S125, and the drive control unit 173 retracts the formed FAB 301 to a predetermined position without adhering to the target pad electrode 321. The arithmetic processing unit 170 executes, for example, a warning process such as a warning sound, notifies the operator of the interruption of the process, and terminates the series of processes.

By adopting such a process sequence, a defect such as a short circuit between the pad electrodes 321 can be prevented.

Fig. 8 is a flowchart illustrating a processing sequence of a third example including the core shift measurement of the FAB of the present embodiment. In the third embodiment, the FAB actually formed in the execution of the wiring operation is monitored, and in the case where the measurement result satisfies a certain condition, the wiring operation is continued on the one hand and the discharge condition is adjusted on the other hand. The illustrated flow starts at a point in time when a wiring operation is started for each semiconductor chip 320 provided on the substrate 330 of the stage 220, as in the flow of fig. 7. In addition, the same processes as those described using fig. 6 and 7 are assigned the same process numbers, and thus the description thereof is omitted except for the cases specifically mentioned.

When the flow starts, the steps S111 to S115 execute the same processing as the corresponding steps of fig. 7. When the process advances from step S115 to step S131, the measurement unit 171 determines whether or not the measurement result satisfies a first reference set in advance. The first criterion is a criterion that determines that there is a high possibility of causing a problem such as a short circuit between the pad electrodes 321 when the first criterion is not satisfied, and the range is defined based on the core shift evaluation value, for example. When the measurement result satisfies the first criterion, the process advances to step S121, where the first bonding is started. If the measurement result does not satisfy the first criterion, the process proceeds to step S125, where the backoff and warning process is executed, and a series of processes is terminated.

When the process advances to step S121, the process continues as described above until step S123. After the step S132, the measurement unit 171 determines whether or not the measurement result measured in the step S115 satisfies the second criterion. The second criterion is a criterion that can be evaluated as an optimal shape when the second criterion is satisfied, and a range that is less deviated from the first criterion is set. If the second criterion is not satisfied and the first criterion is satisfied, the direct connection operation may not cause a defect such as a short circuit between the pad electrodes 321, but the first criterion may not be satisfied due to some chance. Therefore, when the measurement unit 171 determines in step S132 that the second criterion is not satisfied, the process proceeds to step S133, and the adjustment unit 172 adjusts the discharge condition in consideration of the measurement result. That is, the parameters of the discharge conditions are changed according to the magnitude or direction of the offset. Then, the process advances to step S124. When the measurement unit 171 determines in step S132 that the second criterion is satisfied, the process skips step S133 and proceeds to step S124.

By adopting such a process sequence, it is possible to prevent a defect such as a short circuit between the pad electrodes 321, and to continuously adjust the discharge conditions, so that the wiring operation can be performed more optimally. Further, when the FAB 301 thus formed continuously is observed, the change in the offset can be grasped. The adjustment unit 172 may adjust the discharge condition in consideration of such a change. In addition, if a learned model generated from the measured core shift evaluation value and learning data of the shift of the FAB 301 formed by the adjusted discharge condition is prepared, the adjustment unit 172 may adjust the discharge condition using such a learned model. In this case, the data obtained by the actual online operation may be used as learning data for relearning.

In the wire bonding machine 100 described above, the imaging unit is constituted by two imaging units, that is, the first imaging unit 151 and the second imaging unit 152, but the imaging unit may be constituted by one imaging unit from the viewpoint of simplifying the apparatus. Fig. 9 is a perspective view schematically showing an essential part of a wire bonding machine 100' according to another embodiment. The same components as those of the wire bonding machine 100 are denoted by the same reference numerals, and description thereof is omitted.

The wire bonding machine 100' differs from the wire bonding machine 100 in that: the image pickup section is constituted by one image pickup unit 151'; and the image capturing unit 151' is provided to the stand 210. In the case where the image pickup section is constituted by one image pickup unit, it is preferable to set the line tail including the FAB 301 so as to be photographed from the direction orthogonal to the discharge direction as described above. The wire bonding machine 100' includes the imaging unit 151' to take the wire tail from the Y-axis positive direction, but may include the imaging unit 151' to take the wire tail from the Y-axis negative direction.

In addition, if the imaging unit 151' is provided so as to be supported by the gantry 210, the movement does not occur with the head movement, and therefore, the line tail can be stably observed. However, at this time, the space in which the wire tail can be photographed is limited, and thus the drive control unit 173 needs to drive the head 110 and the tool 120 so that the wire tail is located in the space. From the standpoint, the structure in which the image pickup unit is supported by the stand 210 is preferable in the case of implementing the first embodiment. In addition, a plurality of imaging units may be provided in the gantry 210, and the tail of the line may be observed from two or more directions.

Although the wire bonding machine 100 has been described as an example of the wire bonding apparatus, the bonding apparatus to which the method or structure for measuring the misalignment of the FAB of the present embodiment is applicable is not limited to the example of the wire bonding machine 100 in which two bonding points are connected by a wire. For example, the present invention is applicable to a bump bonder that forms bumps on a plurality of electrodes on a substrate.

Description of symbols

100. 100': wire bonding machine

110: head part

120: tool part

130: first image pickup unit

131: gas torch

132: wire clamp

133: porcelain nozzle

134: converter

141: head driving motor

142: tool driving motor

151: first image pickup unit

151': image pickup unit

152: second camera unit

170: arithmetic processing unit

171: measuring part

172: adjusting part

173: drive control unit

180: storage unit

190: input/output device

210: stand for stand

220: platform

300: lead wire

301: FAB (without air balloon)

320: semiconductor chip

321: pad electrode

322: wire electrode

330: substrate board

Claims

1. A wire bonding apparatus comprising:

a porcelain nozzle for supplying the bonding wire;

a torch forming a free air ball on a wire tail of the bonding wire extending from the porcelain nozzle;

an imaging unit configured to capture the tail of the wire with the free air ball formed at a tip end thereof by the torch; and

and a measuring unit configured to measure a displacement of the airless ball with respect to a center axis of the joint line based on the image output from the imaging unit.

2. The wire bonding apparatus according to claim 1, wherein the measurement portion measures a first protrusion amount as a protrusion amount of the airless ball in one direction with respect to a center axis of the bonding wire and a second protrusion amount as a protrusion amount of the airless ball in another direction opposite to the one direction with respect to the center axis of the bonding wire.

3. The wire bonding apparatus according to claim 1 or 2, wherein the measurement portion measures an amount of misalignment of a center of the free air ball with respect to a center axis of the bonding wire.

4. The wire bonding apparatus according to any one of claims 1 to 3, wherein the imaging section is provided so as to be free from shooting the wire tail in a direction orthogonal to a direction in which the wire tail is projected from the porcelain nozzle and a discharge direction of arc discharge generated between the torch and the wire tail.

5. The wire bonding apparatus according to any one of claims 1 to 4, wherein the image pickup section includes: and a plurality of imaging units for imaging the wire tail from a plurality of directions orthogonal to the extending direction of the wire tail from the porcelain nozzle.

6. The wire bonding apparatus according to any one of claims 1 to 5, comprising: and an adjustment unit that adjusts the discharge condition of the torch based on the measurement result obtained by the measurement unit.

7. A control method of a wire bonding apparatus, comprising:

a wire tail forming step of forming a wire tail by extending the bonding wire from the front end of the porcelain nozzle;

an airless ball forming step of forming an airless ball at a front end portion of the wire tail using a torch;

an imaging step of imaging the wire tail formed with the non-air balloon; and

and a measurement step of measuring a shift of the airless ball with respect to a center axis of the bonding wire based on the image output in the imaging step.

8. A control program of a wire bonding apparatus, causing a computer to execute:

an imaging step of imaging the wire tail formed with the non-air balloon; and