Method for inspecting device, and device

Abstract

This method for inspecting a wire bonding device comprises a step for bringing a capillary into a state of contact with an nth substrate electrode, a step for outputting a drive current including an AC sweep current component swept from a lower-limit frequency to an upper-limit frequency, a step for obtaining an output value as a result of movement of the capillary in a direction following an axis due to force caused by the drive current during a period in which the sweeping step is executed, and a step for obtaining an nth frequency response using the output value and an input value obtained from a drive current command. First to Nth frequency responses are obtained by repeating the preparation step, the sweeping step, the acquisition step, and the calculation step while changing the location from the first substrate electrode to the Nth substrate electrode.

Description

Method and apparatus for inspecting an apparatus

[0001] The present disclosure relates to a method and an apparatus for inspecting an apparatus.

[0002] For example, a wire bonding apparatus bonds a bonding wire to an electrode of a semiconductor chip. The bonding wire is pressed against an electrode or the like of the semiconductor chip from a component called a capillary, and receives heat, ultrasonic waves, or the like from the capillary. As a result, the bonding wire is bonded to the electrode of the semiconductor chip. Such a bonding operation is referred to as bonding. Patent Documents 1 and 2 disclose technologies related to an apparatus for determining the quality of wire bonding.

[0003] Japanese Unexamined Patent Application Publication No. 2020-47637 Patent No. 6664300

[0004] The result of a bonding operation is affected by various factors. If factors that may reduce the quality of the bonding operation can be extracted in advance and countermeasures can be taken, it becomes possible to obtain a desired bonding operation result. Therefore, there has been a demand for evaluating the result of a bonding operation without performing the actual bonding operation.

[0005] The present disclosure describes a method and an apparatus for inspecting an apparatus that can evaluate whether a desired bonding operation result can be obtained.

[0006] A method for inspecting an apparatus according to one aspect of the present disclosure includes: a preparation step of bringing a tool into contact with an n-th evaluation unit (n is an integer of 1 or more); a sweep step of outputting a drive current including an alternating current sweep current component swept from a lower limit frequency to an upper limit frequency; an acquisition step of obtaining an output value that is a result of the tool moving in a direction along a predetermined axis by a force caused by the drive current during a period in which the sweep step is executed; and a calculation step of obtaining an n-th frequency response using an input value and the output value obtained from a drive signal command that defines the drive current, wherein first to N-th frequency responses are obtained by repeating the preparation step, the sweep step, the acquisition step, and the calculation step while changing locations from the first evaluation unit to an N-th evaluation unit (N is an integer of 2 or more).

[0007] This method allows for obtaining frequency responses for each evaluation unit, which are distinct parts of the system. These frequency responses enable comparison of the state of each evaluation unit during the joining process using the tool. By comparing the frequency responses of each evaluation unit, it becomes possible to evaluate whether the state of each unit is conducive to achieving the desired joining result. In other words, it allows for evaluation of whether the joining device can achieve the desired joining result.

[0008] The above method may further include a resonance frequency extraction step of extracting the first to nth primary resonance frequencies, which are the first resonance frequencies, from each of the first to nth frequency responses, and a resonance frequency evaluation step of evaluating the variation in the first to nth resonance frequencies. The variation in resonance frequencies indicates the stiffness state of the structural system affected by tool vibration. As a result, the stiffness of the structural system affected by tool vibration may affect the outcome of the joining operation. Therefore, by evaluating the resonance frequencies that indicate the stiffness of the structural system affected by tool vibration, it is possible to evaluate whether or not the desired joining operation result can be obtained.

[0009] The above method may further include a gain extraction step of extracting the first to nth gains corresponding to the first to nth primary resonant frequencies, which are the first resonant frequencies, from each of the first to nth frequency responses, and a gain evaluation step of evaluating the variation in the first to nth gains. The variation in gains indicates the state of the structural system affected by tool vibration. As a result, the state of the structural system affected by tool vibration may affect the outcome of the joining operation. Therefore, by evaluating the gains that indicate the state of the structural system affected by tool vibration, it is possible to evaluate whether or not the desired outcome of the joining operation can be obtained.

[0010] In the preparation step of the above method, the tool may be pressed against the nth evaluation section with a predetermined load. This step allows for the simulation of the conditions when performing the actual joining work.

[0011] In the above method, the nth evaluation unit is provided on the mth workpiece (where m is an integer of 1 or more), and the (n+1)th evaluation unit may be provided on a workpiece (m+1) that is different from the mth workpiece. This step allows the frequency response to be obtained for each workpiece. As a result, it is possible to evaluate whether the desired bonding operation result can be obtained for each workpiece.

[0012] In the above method, the nth evaluation unit is provided on the mth workpiece (where m is an integer of 1 or more), and the (n+1)th evaluation unit may also be provided on the mth workpiece. This step allows for obtaining a frequency response for each of several evaluation units provided on a given workpiece. As a result, it is possible to evaluate whether the desired bonding result can be obtained for each of the multiple evaluation units provided on a single workpiece.

[0013] Another embodiment of the present disclosure is an apparatus comprising: a tool extending in the direction of a predetermined axis and for joining a workpiece to a workpiece; an arm for holding the tool and for reciprocating the tool in a direction along the predetermined axis; a drive unit driven by a drive current to move the arm so as to reciprocate the tool in a direction along the predetermined axis; a measurement unit for obtaining an output value which is the result of the tool moving in a direction along the predetermined axis due to a drive current which includes an AC sweep current component swept from a lower frequency limit to an upper frequency limit; and a controller for outputting the drive current. The controller has an input value calculation unit for obtaining an input value based on the drive current; an output value calculation unit for obtaining an output value based on the output of the measurement unit; and a response calculation unit for obtaining a frequency response from the input value and the output value. This apparatus can also be used to evaluate whether the desired joining operation result can be obtained.

[0014] The method and apparatus for inspecting the apparatus of this disclosure can be used to evaluate whether or not the desired joining operation result can be obtained.

[0015] Figure 1 is a diagram showing the configuration of a wire bonding apparatus according to an embodiment. Figure 2 is a flowchart showing the main steps of a method for inspecting the wire bonding apparatus according to an embodiment. Figure 3 is a flowchart detailing the steps for evaluating the frequency response shown in Figure 2. Figures 4(a) and 4(b) are examples of multiple frequency responses. Figure 5 is a flowchart showing another example of the steps for evaluating the frequency response shown in Figure 2.

[0016] The method and apparatus for inspecting the apparatus of this disclosure will be described in detail below with reference to the attached drawings. In the description of the drawings, the same elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0017] The wire bonding apparatus 1 shown in Figure 1 presses the capillary 31 toward the substrate electrode 92 while the bonding wire (to be bonded) is sandwiched between the capillary 31 (tool) and the substrate electrode 92 of the semiconductor chip 90 (to be bonded). As a result, the bonding wire is bonded to the substrate electrode 92. In other words, the wire bonding apparatus 1 is an example of a bonding apparatus, and the bonding operation illustrated in this embodiment is wire bonding. In addition to bonding load, the wire bonding apparatus 1 may also apply ultrasonic waves or heat to the bonding wire.

[0018] The wire bonding apparatus 1 comprises a feeder unit 2 and a bonding unit 3. The feeder unit 2 holds a plurality of semiconductor chips 90. Each semiconductor chip 90 has an apparatus substrate 91 and a plurality of substrate electrodes 92. The wire bonding apparatus 1 connects the substrate electrodes 92 of the semiconductor chips 90 arranged in the feeder unit 2 with bonding wires.

[0019] <Feeder Unit> The feeder unit 2 includes a feeder stage 21 and a wind clamper 22. The feeder stage 21 has a function to temporarily fix the object to be wire bonded. For example, the feeder stage 21 has suction holes 211 including openings provided on the main surface 21a of the stage. The chip unit 9 is placed on the main surface 21a of the stage. The chip unit 9 is composed of a unit substrate 95 and a plurality of semiconductor chips 90 arranged on the main surface of the unit substrate 95.

[0020] When the chip unit 9 is placed on the main surface 21a of the stage, it closes the suction holes 211. In this state, when negative pressure is applied to the suction holes 211, the chip unit 9 is attracted to the main surface 21a of the stage. As a result, the chip unit 9 is restrained relative to the feeder stage 21. More specifically, the chip unit 9 receives a force that pulls it toward the feeder stage 21 at the position of the suction holes 211. In other words, the chip unit 9 is restrained at the position of the suction holes 211. Then, after bonding is completed, when the supply of negative pressure to the suction holes 211 is stopped, the restraint of the chip unit 9 toward the feeder stage 21 is released.

[0021] The chip unit 9, placed on the main surface 21a of the stage, is temporarily restrained from the feeder stage 21 by the wind clamper 22. The wind clamper 22 holds down the edges of the main surface of the unit substrate 95. The wind clamper 22 then exposes multiple semiconductor chips 90 through the clamper opening 221. In other words, the chip unit 9 is restrained from the feeder stage 21 in the thickness direction at the outer peripheral edge of the unit substrate 95.

[0022] <Bonding Unit> The bonding unit 3 includes a capillary 31, a bonding tool 32, and a Z-axis drive unit 33.

[0023] The capillary 31 presses the bonding wire against the object to be bonded. The capillary 31 may also apply ultrasonic waves to the bonding wire. The capillary 31 has a cylindrical portion and a conical portion, and is provided with a through hole extending from one end face to the other. The bonding wire is fed out through this through hole.

[0024] The bonding tool 32 detachably holds the cylindrical portion of the capillary 31 at its tip. The bonding tool 32 is connected to the Z-axis drive unit 33 at its base. The bonding tool 32 moves the held capillary 31 in the X-axis, Y-axis, and Z-axis directions, respectively.

[0025] The Z-axis drive unit 33 is provided on the base end side of the bonding tool 32. The Z-axis drive unit 33 is a motor that oscillates the bonding tool 32 around the pivot center P1 as its central axis. The Z-axis drive unit 33 consists of a stator 331 including a coil and a movable element 332 including a magnet. The stator 331 is attached to the bonding unit body 30. The movable element 332 is attached to the bonding tool 32.

[0026] The Z-axis drive unit 33 is driven by a drive current M52 supplied from the motor driver 34. As shown in the example in Figure 1, when the movable element 332 moves clockwise at the pivot center P1, the tip of the bonding tool 32 also moves clockwise. Microscopically, the capillary 31 moves in the positive Z-axis direction. The positive Z-axis direction is the direction away from the object to be wire bonded. When the movable element 332 moves counterclockwise at the pivot center P1, the tip of the bonding tool 32 also moves counterclockwise. Microscopically, the capillary 31 moves in the negative Z-axis direction. The negative Z-axis direction is the direction towards the object to be wire bonded.

[0027] The position of the capillary 31 along the Z-axis can be obtained from the information output by an encoder 35 provided on the base end of the bonding tool 32. In the following description, the information indicating the position of the capillary 31 along the Z-axis will be referred to as the output value indicating the capillary position. The information output by the encoder 35 will be referred to as encoder data D35. In the example shown in Figure 1, the encoder 35 is provided on the base end of the bonding tool 32, opposite to the tip of the bonding tool to which the capillary 31 is attached. The encoder data D35 output by the encoder 35 is transmitted to the controller 5. The controller 5 uses the encoder data D35 to obtain the output value, which is the capillary position information. The process for obtaining the output value will be described later.

[0028] The wire bonding apparatus 1 includes an encoder 35 and a load sensor 39. The encoder 35 is for measuring the position of the capillary 31 in the Z-axis direction. In other words, the encoder 35 is a Z-axis position sensor. The encoder 35 passes the measured encoder position information D35 to the controller 5. The load sensor 39 detects or measures the reaction force that the capillary 31 receives from the object to be bonded when the capillary 31 is pressed against the object to be bonded. For example, the load sensor 39 is used to detect when the capillary 31 or bonding wire is in contact with the object to be bonded. The load sensor 39 also measures the bonding load that the capillary 31 applies to the bonding wire when it presses against the object to be bonded. The load sensor 39 passes the detected or measured data D39 to the controller 5, which will be described later.

[0029] <Controller> Controller 5 is a computer having at least a processor and memory. Controller 5 is one element of the servo system for the Z-axis drive unit 33. The servo system for the Z-axis drive unit 33 is a closed loop including Controller 5, motor driver 34, Z-axis drive unit 33, and encoder 35. Controller 5, which performs calculations for the servo control system, gives a drive current command C52 to the motor driver 34. The motor driver 34 gives a drive current M52 proportional to the drive current command C52 to the Z-axis drive unit 33, which is a linear motor. The Z-axis drive unit 33 generates thrust proportional to the current. This thrust causes the bonding tool 32 to oscillate. The oscillation of the bonding tool 32 is captured by the encoder 35. The encoder 35 obtains the position along the Z-axis direction at the base end of the bonding tool 32 as encoder data D35. The encoder 35 then provides the encoder data D35 to Controller 5. The controller 5 obtains a drive current command C52 based on the encoder data D35.

[0030] Controller 5 also performs the function of obtaining the frequency response characteristics of the servo system. The servo system's response characteristics, in this context, are those in which the position of the capillary 31 along the Z-axis, derived from the drive current command C52, is the target position, and the resulting position of the capillary 31 along the Z-axis, derived from the encoder data D35, is the result. The sum of the results obtained for each frequency relative to this target is the servo system's frequency response characteristics.

[0031] The frequency response characteristics of the servo system in this embodiment are for the target position and the resulting position. In other words, the frequency response characteristics of the servo system in this embodiment are for a mechanical system whose elements are physical components. This mechanical system includes at least a bonding tool 32, a capillary 31, and a chip unit 9 as its components. In other words, when defining this mechanical system, the capillary 31 is in contact with at least the semiconductor chip 90. More specifically, the capillary 31 is pressed against the semiconductor chip 90 with a predetermined bonding load.

[0032] Controller 5 includes several functional components that are realized by the processor executing a program. Controller 5 has an encoder data acquisition unit 51, a drive current command unit 52, a sweep current component command unit 53, an input value calculation unit 54, an output value calculation unit 55, a response calculation unit 56, and a response output unit 57. The encoder data acquisition unit 51, the drive current command unit 52, the input value calculation unit 54, and the output value calculation unit 55 are elements that constitute the servo system described above.

[0033] The encoder data acquisition unit 51 receives encoder data D35 output by the encoder 35. The encoder data acquisition unit 51 stores the received encoder data D35 in memory, for example. The drive current command unit 52 generates a drive current command C52 and provides the generated drive current command C52 to the motor driver 34. The input value calculation unit 54 calculates the input value obtained from the drive current command C52. The output value calculation unit 55 calculates the position (output value) of the capillary 31 along the Z-axis direction obtained from the encoder data D35. The response calculation unit 56 calculates the gain obtained from the input value and the output value. The response calculation unit 56 calculates the gain for each frequency. As a result, frequency responses G31, G32, and G33 of vibration, as illustrated in Figure 4(a), are obtained. Frequency response G31 is obtained with the capillary 31 pressed against the first semiconductor chip 90. Frequency response G32 is obtained with the capillary 31 pressed against the second semiconductor chip 90. The frequency response G33 was obtained with the capillary 31 pressed against the third semiconductor chip 90.

[0034] These frequency responses G31, G32, and G33 represent the mechanical state of the wire bonding apparatus 1 when wire bonding is performed. The mechanical state may be simulated as a vibration system in which the Z-axis drive unit 33 is the excitation source and the position where the capillary 31 contacts the semiconductor chip 90 is the output. This vibration system is composed of the moment of inertia of the Z-axis drive unit 33, the stiffness of the bonding tool 32, the stiffness of the capillary 31, the stiffness of the unit substrate 95, etc. The frequency responses G31, G32, and G33 visualize the state of the vibration system including all of these effects. When two frequency responses obtained from different semiconductor chips 90 can be considered the same, the mechanical states of the wire bonding apparatus 1 when wire bonding is performed can be considered equivalent. When two frequency responses obtained from different semiconductor chips 90 cannot be considered the same, the mechanical states of the wire bonding apparatus 1 when wire bonding is performed cannot be considered equivalent. In other words, it can be expected that there is a difference in at least one of the factors exemplified above that affect the mechanical state of the wire bonding apparatus 1.

[0035] The response output unit 57 outputs the frequency response or various information based on the frequency response. For example, the response output unit 57 may display data on a display that shows multiple frequency responses in a single coordinate system. The response output unit 57 may also display the primary resonant frequency and / or gain extracted from each of the multiple frequency responses on the display.

[0036] Figures 4(a) and 4(b) are examples of frequency responses displayed on a display. For example, Figure 4(a) shows three frequency responses G31, G32, and G33 obtained from each of the three semiconductor chips 90.

[0037] In the example shown in Figure 4(a), the three frequency responses G31, G32, and G33 show almost the same trend. From this result, it can be concluded that the stiffness affecting wire bonding is not varied in each of the three semiconductor chips 90. Based on these results, it can be predicted that all three semiconductor chips 90 will yield the desired bonding result. In other words, it can be predicted that it is unlikely that two of the three semiconductor chips 90 will yield the desired bonding result, while the remaining one will not.

[0038] In the example in Figure 4(b), the three frequency responses G41, G42, and G43 differ from those in the example in Figure 4(a), indicating that their trends are more varied. From these results, it can be concluded that the stiffness affecting wire bonding varies in each of the three semiconductor chips 90. Based on these results, it can be predicted that, for example, two of the three semiconductor chips 90 will achieve the desired bonding result, while the remaining one will not.

[0039] The evaluation of the multiple frequency responses G31, G32, and G33 described above is just one example. There can be various variations in the evaluation method for the multiple frequency responses G31, G32, and G33. For example, an acceptable range may be set for the variation in the primary resonant frequency and / or gain. If the primary resonant frequency and / or gain fall within the acceptable range, it can be determined that there is a high probability of obtaining the desired bonding result for each of the multiple semiconductor chips 90. If the primary resonant frequency and / or gain do not fall within the acceptable range, it can be determined that there is a low probability of obtaining the desired bonding result for each of the multiple semiconductor chips 90. Furthermore, a threshold may be set for the primary resonant frequency and / or gain. A semiconductor chip 90 that obtains a primary resonant frequency and / or gain exceeding the threshold may be determined to have a high probability of obtaining the desired bonding result. A semiconductor chip 90 that obtains a primary resonant frequency and / or gain that does not exceed the threshold may be determined to have a low probability of obtaining the desired bonding result.

[0040] Furthermore, the evaluation of the multiple frequency responses G31, G32, and G33 may be performed by an operator or by the controller 5. In other words, the operator may predict the bonding result by checking the results shown in Figure 4(a) displayed on the display. Alternatively, the controller 5 may extract the primary resonant frequency from the results shown in Figure 4(a) displayed on the display and determine whether the range of variation exceeds a preset tolerance range. If the range of variation exceeds the preset tolerance range, it may be determined that there is a possibility that the desired bonding result cannot be obtained for each of the three semiconductor chips 90. If the range of variation does not exceed the preset tolerance range, it may be determined that there is a high probability that the desired bonding result can be obtained for each of the three semiconductor chips 90.

[0041] <Method for inspecting the wire bonding apparatus> Next, the method for inspecting the wire bonding apparatus 1 will be explained with reference to the flowchart shown in Figure 2.

[0042] First, the sweep component command C53 is determined (S1). This operation is performed by the sweep current component command unit 53. The sweep current component command unit 53 determines and outputs the sweep component command C53 for obtaining the frequency response. The sweep component command C53 can be defined by a lower frequency limit, an upper frequency limit, the speed from the lower frequency limit to the upper frequency limit (sweep speed), and the sweep amplitude. The sweep component command C53 sets the lower frequency limit to a value lower than the expected primary resonance frequency and the upper frequency limit to a value higher than the primary resonance frequency.

[0043] Next, the capillary 31 is pressed against the nth semiconductor chip 90 (S2). This operation is performed by the drive current command unit 52. The capillary 31 is pressed against the substrate electrode 92, which is an example of the evaluation unit. The drive current command unit 52 generates thrust in the Z-axis drive unit 33 to achieve a preset pressing load. At this time, since the capillary 31 is only statically pressing against the semiconductor chip 90, the drive current M52 based on the drive current command C52 is a DC current with a predetermined bias.

[0044] Next, a sweep component command C53 is output (S3). The sweep component command C53 is superimposed on the drive current command C52 already output in the previous step S2. As a result, an alternating current command that changes from a lower limit frequency to an upper limit frequency at a predetermined sweep speed is superimposed on a current command that is a direct current having a predetermined bias.

[0045] Next, n-th encoder data D35 is acquired (S4). This operation is executed by the encoder 35 and an encoder data acquisition unit 51. This operation ends after the sweep component command C53 reaches the upper limit frequency.

[0046] Next, an n-th output value is obtained from the n-th encoder data D35 (S5). This operation is executed by an output value calculation unit 55. The output value calculation unit 55 obtains an output value using the encoder data D35. The position indicated by the encoder data D35 is actually the position of the bonding tool 32 along the Z-axis direction. The base-end reference point P35 may be the position of the encoder 35. On the other hand, the output value obtained in this operation is the position along the Z-axis direction of the tip-side reference point P31 passing through the axis of the capillary 31. The tip-side reference point P31 may be the position of the capillary 31.

[0047] Then, the distance from the swing center P1 of the Z-axis drive unit 33 to the base-end reference point P35 is L1, and the distance from the swing center P1 of the Z-axis drive unit 33 to the tip-side reference point P31 is L2. Accordingly, the position (output value) of the tip-side reference point P31 along the Z-axis direction is obtained by the following formula (1). Position of tip-side reference point P31 (capillary position) = (-1) × L2 / L1 × Position of base-end reference point P35 ...(1)

[0048] Next, an input value is obtained from the drive current command C52 (S6). This operation is executed by an input value calculation unit 54.

[0049] Next, the nth frequency response is obtained from the input value and the nth output value (S7). This operation is performed by the response calculation unit 56. The response calculation unit 56 uses the input value obtained by the input value calculation unit 54 and the output value obtained by the output value calculation unit 55 to obtain gains for each frequency. By obtaining gains from the lower frequency limit to the upper frequency limit, the frequency response for the nth semiconductor chip 90 can be obtained.

[0050] Next, it is determined whether a frequency response has been obtained for all semiconductor chips 90 that are to be inspected (S8). If a frequency response has not been obtained for all semiconductor chips 90 (S8: NO), the frequency response for the next semiconductor chip 90 is obtained. If a frequency response has been obtained for all semiconductor chips 90 (S8: YES), the first to Nth frequency responses are evaluated (S9). As shown in Figure 3, step S9 includes step S91 for extracting the first resonant frequency and step S92 for evaluating the extracted first resonant frequency. An example of the evaluation performed in step S92 has already been described and will not be repeated here.

[0051] By performing the above steps S1 to S9, it is possible to evaluate whether or not the desired wire bonding result can be obtained.

[0052] <Effects> The method for inspecting the wire bonding apparatus 1 includes the steps of: step S2, which is the nth evaluation unit (n is an integer of 1 or more), which is the nth substrate electrode 92, which is in contact with the capillary 31; step S3, which outputs a drive current M52 that includes an AC sweep current component M53 that sweeps from the lower limit frequency to the upper limit frequency; steps S4 and S5, which obtain output values ​​that are the result of the capillary 31 moving in the direction along the axis due to the force caused by the drive current M52 during the period in which step S3 is performed; and step S7, which obtains the nth frequency response using the input value and output value obtained from the drive current command C52. The first to the nth frequency responses are obtained by repeating the preparation step S1, the sweeping step S3, the acquisition steps S4 and S5, and the calculation step S7 while changing the location from the first substrate electrode 92 to the nth substrate electrode 92 (N is an integer of 2 or more).

[0053] This method allows for obtaining frequency responses for each of the substrate electrodes 92, which are distinct from one another. These frequency responses allow for a comparison of the conditions under which wire bonding using the capillary 31 is performed for each substrate electrode 92. By comparing the frequency responses of each substrate electrode 92, it becomes possible to predict whether the bonding environment, including each substrate electrode 92, is capable of achieving the desired wire bonding results. In other words, it is possible to evaluate whether the wire bonding apparatus 1 can achieve the desired wire bonding results.

[0054] The above method includes step S91 of extracting the first to nth primary resonant frequencies, which are the first resonant frequencies, from each of the first to nth frequency responses, and step S92 of evaluating the variation in the first to nth resonant frequencies. The variation in resonant frequencies indicates the stiffness state of the structural system affected by the vibration of the capillary 31. As a result, the stiffness of the structural system affected by the vibration of the capillary 31 may affect the wire bonding results. Therefore, by evaluating the resonant frequencies that indicate the stiffness of the structural system affected by the vibration of the capillary 31, it is possible to evaluate whether or not the desired wire bonding results can be obtained.

[0055] In preparation step S1, the capillary 31 is pressed against the nth substrate electrode 92 with a predetermined load. This step S1 simulates the conditions when actual wire bonding is performed.

[0056] The nth substrate electrode 92 is provided on the mth semiconductor chip 90 (where m is an integer of 1 or more). The (n+1)th substrate electrode 92 is provided on a semiconductor chip 90 that is different from the mth semiconductor chip 90 (the (m+1)th). A frequency response can be obtained for each semiconductor chip 90. As a result, it is possible to evaluate whether the desired wire bonding result can be obtained for each semiconductor chip 90.

[0057] The wire bonding apparatus 1 includes a capillary 31 extending in the direction of a predetermined axis and for joining bonding wires to a bonding target, a bonding tool 32 that holds the capillary 31 and moves the capillary 31 back and forth in the direction along the predetermined axis, a Z-axis drive unit 33 that moves the bonding tool 32 so as to move the capillary 31 back and forth in the direction along the predetermined axis, an encoder 35 for obtaining an output value which is the result of the capillary 31 moving in the direction along the axis due to a drive current M52 which includes an AC sweep current component M53 that is swept from a lower limit frequency to an upper limit frequency, and a controller 5 that outputs a drive current command C52 for the drive current M52. The controller 5 has an input value calculation unit 54 that obtains an input value based on the drive current command C52, an output value calculation unit 55 that obtains an output value based on the output of the encoder 35, and a response calculation unit 56 that obtains a frequency response from the input value and the output value. This wire bonding apparatus 1 can also be used to evaluate whether the desired wire bonding result can be obtained.

[0058] <Modifications> The method for inspecting a wire bonding apparatus and the wire bonding apparatus described herein have been explained above. However, the method for inspecting a wire bonding apparatus and the wire bonding apparatus described herein are not necessarily limited to the embodiments described above, and various modifications can be made without departing from the gist of the invention.

[0059] In the above embodiment, the frequency response was obtained for each semiconductor chip 90. This method allows evaluation of whether the desired bonding result can be obtained for each of the first to nth semiconductor chips 90. For example, the frequency response may be obtained for each of the multiple electrodes provided on a certain semiconductor chip 90. This method allows evaluation of whether the desired bonding result can be obtained for each of the electrodes provided on a single semiconductor chip 90. In short, the nth evaluation unit, the substrate electrode 92, is provided on the mth semiconductor chip 90 (where m is an integer of 1 or more), and the (n+1)th evaluation unit, the substrate electrode 92, may also be provided on the mth semiconductor chip 90. According to this modification, the frequency response can be obtained for each of the several substrate electrodes 92 provided on a certain semiconductor chip 90. As a result, it is possible to evaluate whether the desired wire bonding result can be obtained for each of the multiple substrate electrodes 92 provided on a single semiconductor chip 90.

[0060] In the above embodiment, an evaluation focusing on the first resonant frequency was illustrated. For example, an evaluation focusing on the gain at the first resonant frequency may also be performed. The gain at the first resonant frequency also reflects the state of the system affected by the vibration of the capillary 31. Therefore, variations in the gain may indicate variations in the state of the system affected by the vibration of the capillary 31. In short, as shown in Figure 5, the embodiment may further include a gain extraction step S93 for extracting the first to nth gains corresponding to the first to nth first resonant frequencies, which are the first resonant frequencies, from each of the first to nth frequency responses, and a gain evaluation step S94 for evaluating the variations in the first to nth gains. Variations in the gain indicate the state of the structural system affected by the vibration of the capillary 31. As a result, the state of the structural system affected by the vibration of the capillary 31 may affect the wire bonding results. Therefore, by evaluating the gain that indicates the state of the structural system affected by the vibration of the capillary 31, it is possible to evaluate whether or not the desired wire bonding results can be obtained.

[0061] In the above embodiment, a wire bonding apparatus 1 was exemplified as an apparatus for performing bonding work. The examples of bonding work are not limited to wire bonding, nor are the examples of bonding apparatuses limited to a wire bonding apparatus 1. For example, the method for inspecting a wire bonding apparatus and the wire bonding apparatus of this disclosure can also be applied to a die bonding apparatus that performs die bonding, which is an example of bonding work.

[0062] <Note> This disclosure has the following configuration.

[0063] This disclosure [1] is a method for inspecting an apparatus, comprising: a preparation step of bringing a tool into contact with an nth evaluation unit (where n is an integer of 1 or more); a sweep step of outputting a drive current including an AC sweep current component that sweeps from a lower frequency to an upper frequency; an acquisition step of obtaining an output value which is the result of the tool moving in a direction along a predetermined axis due to a force caused by the drive current during the period in which the sweep step is performed; and a calculation step of obtaining an nth frequency response using an input value obtained from a drive signal command that defines the drive current and the output value, wherein the preparation step, the sweep step, the acquisition step and the calculation step are repeated from a first evaluation unit to an Nth evaluation unit (where N is an integer of 2 or more) while changing locations, thereby obtaining first to Nth frequency responses.

[0064] This disclosure [2] is a method for inspecting the apparatus described in [1], further comprising: a resonance frequency extraction step of extracting first to nth primary resonance frequencies, which are first resonance frequencies, from each of the first to nth frequency responses; and a resonance frequency evaluation step of evaluating the variation of the first to nth resonance frequencies.

[0065] The present disclosure [3] is a method for inspecting the apparatus described in [1] or [2], further comprising: a gain extraction step of extracting first to n gains corresponding to the first to n first resonant frequencies, which are first resonant frequencies, from each of the first to nth frequency responses; and a gain evaluation step of evaluating the variation of the first to nth gains.

[0066] This disclosure [4] is "a method for inspecting the apparatus described in any one of the above [1] to [3], wherein in the preparation step, the tool is pressed against the n evaluation unit with a predetermined load."

[0067] This disclosure [5] is a method for inspecting the apparatus described in any one of the above [1] to [4], wherein the n evaluation unit is provided on the mth workpiece (where m is an integer of 1 or more), and the n+1 evaluation unit is provided on the m+1th workpiece, which is different from the mth workpiece.

[0068] This disclosure [6] is "a method for inspecting the apparatus described in any one of the above [1] to [4], wherein the n evaluation unit is provided on the m workpiece (where m is an integer of 1 or more), and the n+1 evaluation unit is also provided on the m workpiece."

[0069] The present disclosure [7] is a device comprising: a tool extending in the direction of a predetermined axis and for joining a join to an object to be joined; an arm for holding the tool and for reciprocating the tool in a direction along the predetermined axis; a drive unit driven by a drive current to move the arm so as to reciprocate the tool in a direction along the predetermined axis; a measurement unit for obtaining an output value which is the result of the tool moving in a direction along the predetermined axis due to the drive current which includes an AC sweep current component that is swept from a lower frequency to an upper frequency; and a controller for outputting the drive current command, wherein the controller comprises: an input value calculation unit for obtaining an input value based on the drive current; an output value calculation unit for obtaining an output value based on the output of the measurement unit; and a response calculation unit for obtaining a frequency response from the input value and the output value.

[0070] 1...Wire bonding apparatus, 5...Controller, 31...Capillary (tool), 32...Bonding tool, 35...Encoder (measurement unit), 54...Input value calculation unit, 55...Output value calculation unit, 56...Response calculation unit, 90...Semiconductor chip (work to be bonded), 92...Substrate electrode (evaluation unit), M34...Drive current, C52...Drive current command, M52...Drive current, C53...Sweep component command, M53...Sweep current component, S1...Preparation step, S3...Sweep step, S4, S5...Acquisition step, S7...Calculation step, S91...Resonance frequency extraction step, S92...Resonance frequency evaluation step, S93...Gain extraction step, S94...Gain evaluation step.

Claims

1. A method for inspecting an apparatus, comprising: a preparation step of bringing a tool into contact with the nth evaluation unit (where n is an integer of 1 or more); a sweep step of outputting a drive current including an AC sweep current component that sweeps from a lower frequency limit to an upper frequency limit; an acquisition step of obtaining an output value which is the result of the tool moving in a direction along a predetermined axis due to the force caused by the drive current during the period in which the sweep step is performed; and a calculation step of obtaining the nth frequency response using the input value obtained from a drive signal command that defines the drive current and the output value, wherein the preparation step, the sweep step, the acquisition step and the calculation step are repeated from the first evaluation unit to the nth evaluation unit (where N is an integer of 2 or more) while changing the location, thereby obtaining the first to the nth frequency responses.

2. A method for inspecting the apparatus according to claim 1, further comprising: a resonance frequency extraction step of extracting first to nth primary resonance frequencies, which are first resonance frequencies, from each of the first to nth frequency responses; and a resonance frequency evaluation step of evaluating the variation of the first to nth resonance frequencies.

3. A method for inspecting the apparatus according to claim 1, further comprising: a gain extraction step of extracting first to n gains corresponding to the first to n first resonant frequencies, which are first resonant frequencies, from each of the first to n frequency responses; and a gain evaluation step of evaluating the variation of the first to n gains.

4. A method for inspecting the apparatus according to claim 1, wherein in the preparation step, the tool is pressed against the n evaluation section with a predetermined load.

5. A method for inspecting the apparatus according to claim 1, wherein the nth evaluation unit is provided on the mth workpiece (where m is an integer of 1 or more), and the n+1th evaluation unit is provided on a workpiece (m+1) that is different from the mth workpiece.

6. A method for inspecting the apparatus according to claim 1, wherein the n evaluation unit is provided on the m workpiece (where m is an integer of 1 or more), and the n+1 evaluation unit is also provided on the m workpiece.

7. A device comprising: a tool extending in the direction of a predetermined axis and for joining a joint to a workpiece; an arm for holding the tool and for reciprocating the tool in a direction along the predetermined axis; a drive unit driven by a drive current to move the arm so as to reciprocate the tool in a direction along the predetermined axis; a measurement unit for obtaining an output value which is the result of the tool moving in a direction along the predetermined axis due to the drive current which includes an AC sweep current component swept from a lower frequency to an upper frequency; and a controller for outputting the drive current, wherein the controller comprises: an input value calculation unit for obtaining an input value based on the drive current; an output value calculation unit for obtaining an output value based on the output of the measurement unit; and a response calculation unit for obtaining a frequency response from the input value and the output value.

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