TWI771750B - Wire bonding apparatus and wire bonding method - Google Patents

Abstract

A wire bonding apparatus according to an embodiment bonds a wire to a bonding portion by generating an ultrasonic vibration in a state of pressing the wire onto the bonding portion. The wire bonding apparatus includes a bonding tool that causes the wire to contact the bonding portion and applies a load, an ultrasonic horn that generates the ultrasonic vibration, a load sensor that continuously detects the load applied from the bonding tool to the bonding portion, and a controller that controls the operation of the bonding tool and the ultrasonic horn. The controller analyzes data of the load output from the load sensor between when the wire contacts the bonding portion and when the ultrasonic vibration is generated, and controls the operation of the bonding tool and the ultrasonic horn based on an analysis result.

Description

Wire bonding device and wire bonding method

Embodiments of the present invention relate to a wire bonding apparatus and a wire bonding method.

A wire bonding apparatus for bonding a wire to a joined portion of a workpiece is known (Patent Document 1). In such a wire bonding apparatus, it is sought to suppress the occurrence of poor bonding between the part to be bonded and the wire. [Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Application Laid-Open No. 10-98064

[The problem to be solved by the invention]

The problem to be solved by the present invention is to provide a wire bonding apparatus and a wire bonding method which can suppress the occurrence of poor bonding between the part to be bonded and the wire. [Technical means to solve the problem]

The wire bonding apparatus according to the embodiment generates ultrasonic vibration in a state where the wire is pressed against the part to be joined to bond the wire to the part to be joined, and includes a bonding tool for bringing the wire into contact with the part to be joined and apply a load; an ultrasonic welding head, which generates ultrasonic vibration; a load sensor, which continuously detects the load applied to the above-mentioned joined part from the above-mentioned joining tool; and a control part, which controls the above-mentioned joining tool and the above-mentioned ultrasonic wave Action of the welding head. The control unit analyzes the data of the load output from the load cell during the period from the time when the wire contacts the part to be bonded to the generation of the ultrasonic vibration, and controls the bonding tool and the ultrasonic welding head based on the analysis result action.

Hereinafter, each embodiment of the present invention will be described with reference to the drawings. The drawings are schematic or conceptual representations, and the relationship between the thickness and width of each part, and the ratio of sizes between parts are not necessarily the same as the actual objects. Even in the case of showing the same part, the size or ratio of each other may be shown differently according to the drawings. In the description of the application of the present invention and each of the drawings, the same elements as those described above are given the same symbols to the existing drawings, and detailed descriptions are appropriately omitted.

FIG. 1 is a schematic diagram schematically showing a wire bonding apparatus according to an embodiment. FIG. 2 is a schematic view schematically showing a part of the wire bonding apparatus of the embodiment. As shown in FIGS. 1 and 2 , the wire bonding apparatus 100 of the embodiment includes a bonding head 10 , an XY stage 20 , a bonding stage 30 , a load cell 40 , and a control unit 50 .

The bonding head 10 includes a bonding tool 11 , an ultrasonic welding head 12 , a bonding arm 13 , and a drive unit 14 .

The bonding tool 11 draws out the lead wire 3 as a bonding material. The bonding tool 11 is, for example, a bonding capillary. The conducting wire 3 is, for example, an aluminum wire, a gold wire, a silver wire, or a copper wire or the like. The bonding tool 11 brings the wire 3 into contact with the portion to be bonded 2 of the workpiece 1 placed on the bonding stage 30 , and applies a load to the portion to be bonded 2 .

The ultrasonic welding head 12 generates ultrasonic vibrations. The ultrasonic welding head 12 has an ultrasonic vibrator that generates ultrasonic vibration. The ultrasonic welding head 12 supports the bonding tool 11 . The ultrasonic vibration generated from the ultrasonic welding head 12 is transmitted to the wire 3 via the bonding tool 11 . When the lead wire 3 is in contact with the joined part 2 , the ultrasonic vibration is transmitted to the lead wire 3 , and the lead wire 3 is joined to the joined part 2 . The ultrasonic welding head 12 is electrically connected to the control unit 50 .

The engagement arm 13 supports the ultrasonic welding head 12 . That is, the bonding arm 13 supports the bonding tool 11 via the ultrasonic horn 12 . The engaging arm 13 is rotatably provided around the shaft portion 13a.

The drive part 14 drives the engagement arm 13 in the Z direction around the shaft part 13a. The drive unit 14 is, for example, a linear motor. When the joining arm 13 moves in the Z direction, the joining tool 11 and the ultrasonic welding head 12 supported by the joining arm 13 move in the Z direction. By moving the bonding tool 11 in the Z direction, the wire 3 can be brought into contact with the bonded portion 2 and a load can be applied from the bonding tool 11 . The driving unit 14 is electrically connected to the control unit 50 .

In addition, in the specification of this application, the direction which connects the joining tool 11 and the workpiece|work 1 is a Z direction. The X direction is the direction orthogonal to the Z direction. Let the direction orthogonal to the Z direction and the X direction be the Y direction.

The bonding head 10 is mounted on the XY stage 20 . The XY stage 20 is movable in the X direction and the Y direction. When the XY stage 20 moves in the X direction and the Y direction, the bonding head 10 moves in the X direction and the Y direction. That is, the XY stage 20 functions as a positioning mechanism for positioning the bonding tool 11 provided in the bonding head 10 in the X direction and the Y direction. The XY stage 20 is electrically connected to the control unit 50 .

The bonding stage 30 supports the workpiece 1 , which is an object of wire bonding. The bonding stage 30 is supported by, for example, sucking the workpiece 1 . The workpiece 1 is, for example, a semiconductor wafer such as an IC wafer or a substrate. On the joined portion 2, for example, bumps 2a are provided.

The load sensor 40 continuously detects the load applied to the joined portion 2 of the workpiece 1 from the joining tool 11 . The load cell 40 has, for example, a strain gauge. The load sensor 40 may also detect the load applied to the front end of the workpiece 1 side of the bonding tool 11 . In this example, the load cell 40 is mounted on the engagement arm 13 . The load cell 40 is electrically connected to the control unit 50 . The load sensor 40 outputs the detected load data to the control unit 50 .

The control unit 50 controls the operations of the ultrasonic welding head 12 , the driving unit 14 , and the XY stage 20 . The control unit 50 can control the output of the ultrasonic vibration generated from the ultrasonic welding head 12 by controlling the ultrasonic welding head 12 .

The control unit 50 can control the motion of the bonding tool 11 by controlling the motion of the driving unit 14 . More specifically, the control unit 50 can control the position of the bonding tool 11 in the Z direction by controlling the driving unit 14 to drive the bonding arm 13 in the Z direction. Thereby, the control part 50 can control the magnitude of the load applied from the joining tool 11 to the joined part 2 .

The control unit 50 can control the motion of the bonding tool 11 by controlling the motion of the XY stage 20 . More specifically, the control unit 50 can control the position of the bonding tool 11 in the X direction and the Y direction by controlling the XY stage 20 to drive the bonding head 10 in the X direction and the Y direction.

Moreover, the control part 50 analyzes the data of the load output from the load sensor 40, and controls the operation|movement of the bonding tool 11 and the ultrasonic welding head 12 based on the analysis result. The analysis of the data of the load of the control part 50 and the control based on it will be mentioned later.

As shown in FIG. 2 , the wire bonding apparatus 100 , in a state where the wire 3 released from the bonding tool 11 is pressed against the bonded portion 2 of the workpiece 1 placed on the bonding stage 30 12 generates ultrasonic vibration, and the lead wire 3 is joined to the joined part 2 .

FIG. 3 is a graph showing an example of a load signal waveform output from a load cell during wire bonding. FIG. 4 is a graph showing yet another example of the load signal waveform output from the load cell during wire bonding. In FIG. 3 and FIG. 4, the solid line represents the load signal waveform when the bonding state of the wire 3 to the joined part 2 is good, and the dotted line represents the load when the bonding state of the wire 3 to the joined part 2 is poor. signal waveform. The load signal waveform represents the change of the magnitude of the load (load signal) with respect to time.

When the bonding tool 11 is moved (lowered) in the Z direction toward the bonded portion 2 , the wire 3 held by the bonding tool 11 is brought into contact with the bonded portion 2 at time t1 . When the wire 3 comes into contact with the joined part 2, the load detected by the load sensor 40 starts to increase. When the bonding tool 11 is further lowered, the load detected in the load sensor 40 increases continuously and reaches the time point t2. The time t2 is the time when the bonding operation starts, and the bonding tool 11 is used to bond the wire 3 to the bonded portion by applying a specific load to the bonded portion 2 while generating ultrasonic vibration from the ultrasonic welding head 12. 2. The time t2 is, for example, the time when the value of the load becomes equal to or greater than a specific value. The time point t2 may be, for example, the time point when the position in the Z direction of the bonding tool 11 becomes the predetermined position or less. The time point t2 may be, for example, the time point when the moving speed in the Z direction of the bonding tool 11 becomes equal to or less than a predetermined value. When the engagement action starts, the load detected in the load sensor 40 decreases continuously as shown in FIG. 3 , and becomes stable between the time point t3 and the time point t4 . In addition, depending on the engagement conditions, the load detected by the load sensor 40 increases continuously as shown in FIG. 4 and becomes stable between the time point t3 and the time point t4. When the time point t4 is reached, the bonding tool 11 is moved (raised) in the Z direction so as to be separated from the joined portion 2, and the lead wire 3 is cut (lead wire cutting). When the wire is cut, the load detected in the load cell 40 is zero.

As shown in FIGS. 3 and 4 , between the time point t1 and the time point t2, the load signal waveform (solid line) in the case where the bonding state of the wire 3 to the joined part 2 is good is the same as that of the wire 3 to the joined part 2 The load signal waveform (dotted line) is different when the joint state is bad. When the bonding state of the lead wire 3 to the bonded portion 2 is good, the load increases as shown in FIG. 3 and FIG. 4 between the time t1 and the time t2. On the other hand, when the bonding state of the lead wire 3 to the bonded portion 2 is poor, the load increases without inflection between the time point t1 and the time point t2 as shown in FIG. 3 and FIG. 4 , for example.

The difference in the waveform of the load signal between the time point t1 and the time point t2 is considered, for example, due to the difference in the state of the joined portion 2 . In particular, when the bumps 2a are formed on the joined portion 2, the difference in the waveform of the load signal between the time point t1 and the time point t2 is considered, for example, due to the height or shape of the bumps 2a.

In the embodiment, the control unit 50 calculates the determination value based on the load detected by the load cell 40 during the period (the period from the time point t1 to the time point t2 ) after the lead wire 3 comes into contact with the joined part 2 until the ultrasonic vibration is generated. , and based on the judgment value, the operations of the bonding tool 11 and the ultrasonic welding head 12 are controlled. The calculation method of the judgment value will be described later.

More specifically, the control unit 50 performs the engaging operation when the determined value is within a predetermined reference range. Moreover, the control part 50 stops the operation|movement of the welding tool 11 and the ultrasonic welding head 12, for example, when the determination value is outside the reference range, without performing a welding operation. For example, when the determination value is outside the reference range, the control unit 50 may stop the operation of the bonding tool 11 and the ultrasonic horn 12 after the bonding operation is performed.

In addition, the control unit 50 may, for example, perform the engaging operation under the first condition when the determination value is within the reference range, and perform the engagement operation under the second condition different from the first condition when the determination value is outside the reference range. action. In this case, between the first condition and the second condition, at least any one of the output of the ultrasonic vibration generated from the ultrasonic welding head 12 , the time during which the joining operation is performed, and the load applied to the joined part 2 from the joining tool 11 One is different. That is, the control unit 50 may, for example, make the output of the ultrasonic vibration generated from the ultrasonic welding head 12 , the timing of the bonding operation, and the self-bonding tool 11 when the bonding operation is performed when the determination value is outside the reference range. At least any one of the loads applied to the joined portion 2 is changed from the situation that the determination value is within the reference range.

In addition, in the control part 50, the part which performs determination value calculation, and the part which performs operation control of each part can be provided separately. That is, the control unit 50 may have a control area for controlling the operation of each unit, and an analysis area for calculating a determination value.

Moreover, the control part 50 can estimate the quality of the bonding state of the lead wire 3 with respect to the to-be-joined part 2 based on a determination value, for example. In this case, the control unit 50 may display the estimation result of the quality of the bonding state on a display unit or the like electrically connected to the control unit 50 .

Hereinafter, an example of the calculation method of the judgment value will be described. FIGS. 5( a ) and 5 ( b ) are explanatory diagrams showing an example of the calculation method of the determination value. FIG. 5( a ) shows a load signal waveform in which the bonding state of the lead wire 3 to the bonded portion 2 is good. On the other hand, FIG.5(b) shows the load signal waveform in which the bonding state of the lead wire 3 with respect to the to-be-joined part 2 is bad.

As shown in FIGS. 5( a ) and 5 ( b ), the determination value is, for example, the waveform of the load signal detected by the load cell 40 during the period from the time when the lead wire 3 and the joined part 2 are in contact until the ultrasonic vibration is generated. The time integral value of the load in any time interval.

In the examples of FIG. 5( a ) and FIG. 5( b ), the arbitrary time interval is the period from the time point ta to the time point tb. The time point ta and the time point tb are any time points during the period from the time point t1 to the time point t2. The time point ta may be the same as the time point t1. In FIGS. 5( a ) and 5( b ), the time-integrated value of the load in the period from the time point ta to the time point tb is shown as the area of the region indicated by the diagonal lines.

As shown in FIGS. 5( a ) and 5 ( b ), for example, the time integral value S1 at which the bonding state of the wire 3 to the joined part 2 is good is greater than the time integration value S1 that the wire 3 has a poor bonding state to the joined part 2 . Time integral value S2. In this case, the lower limit of the reference range is set to a value larger than the time integration value S2 and smaller than the time integration value S1. In addition, the upper limit of the reference range is set to a value larger than the time integration value S1.

FIGS. 6( a ) and 6( b ) are explanatory diagrams showing a variation of the calculation method of the determination value shown in FIGS. 5( a ) and 5 ( b ). In FIGS. 6( a ) and 6 ( b ), the load signal waveforms in which the bonding state of the lead wire 3 to the bonded portion 2 is good are shown.

As shown in FIG. 6( a ), the determination value can be the sum of the load in any time interval of the load signal waveform detected by the load sensor 40 during the period from the time when the lead wire 3 and the joined part 2 are in contact until the ultrasonic vibration is generated. Part of the time integral value.

In the example of FIG. 6( a ), the determination value is represented by, for example, S-Fmin×(tb-ta). S is the time-integrated value S1 or S2 of the load during the period from the time point ta to the time point tb shown in FIG. 5( a ) and FIG. 5( b ). Fmin is the size of the load at the time point ta. In FIG.6(a), S-Fmin*(tb-ta) is shown as the area of the area|region shown with a diagonal line.

As shown in FIG. 6( b ), the determination value can also be an arbitrary time interval of the load signal waveform detected by the load sensor 40 during the period after the lead wire 3 is in contact with the joined part 2 until the ultrasonic vibration is generated The ratio of the time integral value (area ratio) within.

In the example of FIG.6(b), the determination value is represented by Sm/Sn, for example. Sm is, for example, S-Fmin×(tb-ta) shown in FIG. 6( a ). Sm may be, for example, the time-integrated value S1 or S2 of the load during the period from the time point ta to the time point tb shown in FIG. 5( a ) and FIG. 5( b ). In FIG.6(b), Sm is shown as the area of the area|region shown with an oblique line. Sn is shown as the area of a region in which Sm is removed from a rectangle SQ having a point P at a time point ta and a point Q at a time point tb on the load signal waveform as diagonal corners.

7(a) and 7(b) are explanatory diagrams showing still another example of the calculation method of the determination value. FIG. 7( a ) shows the load signal waveform when the bonding state of the lead wire 3 to the bonded portion 2 is good. On the other hand, FIG.7(b) shows the load signal waveform of the case where the bonding state of the lead wire 3 with respect to the to-be-joined part 2 is bad.

As shown in FIGS. 7( a ) and 7 ( b ), the determination value may be, for example, a value detected by the load cell 40 during the period after the lead wire 3 comes into contact with the joined portion 2 until the ultrasonic vibration is generated. The maximum distance between the straight line connecting any two points on the load signal waveform and the load signal waveform between the two points.

In the example of FIG.7(a) and FIG.7(b), any two points are point p1 and point p2. The point p1 and the point p2 are arbitrary points on the waveform of the load signal during the period from the time point t1 to the time point t2. A straight line connecting any two points is straight line A. In FIGS. 7( a ) and 7 ( b ), the determination value is represented by the distance D between the straight line A and the point X on the load signal waveform that is farthest from the straight line A between the point p1 and the point p2 . Furthermore, when the point X is located above the line A, the distance D is a positive value, and when the point X is located below the line A, the distance D is a negative value. That is, the distance D1 in Fig. 7(a) is a positive value, and the distance D2 in Fig. 7(b) is a negative value.

As shown in FIG. 7( a ) and FIG. 7( b ), for example, the distance D1 in the case where the bonding state of the wire 3 to the joined part 2 is good is greater than the distance D1 when the bonding state of the wire 3 to the joined part 2 is poor The distance D2 of the situation. In this case, the lower limit of the reference range is set to a value larger than the distance D2 and smaller than the distance D1. In addition, the upper limit of the reference range is set to a value larger than the distance D1.

FIGS. 8( a ) and 8( b ) are explanatory diagrams showing another example of the calculation method of the determination value. FIG. 8( a ) shows a load signal waveform when the bonding state of the lead wire 3 to the bonded portion 2 is good. On the other hand, FIG.8(b) shows the load signal waveform of the case where the bonding state of the lead wire 3 with respect to the to-be-joined part 2 is bad.

As shown in FIG. 8( a ) and FIG. 8( b ), the determination value may be, for example, a load signal detected by the load cell 40 during the period after the lead wire 3 is in contact with the joined portion 2 until the ultrasonic vibration is generated The magnitude of the load at any point in the waveform.

In the example of FIG.8(a) and FIG.8(b), the arbitrary time point tc is an arbitrary time point in the period from the time point t1 to the time point t2.

As shown in FIG. 8( a ) and FIG. 8( b ), for example, the magnitude L1 of the load at the time point tc when the bonding state of the wire 3 to the joined part 2 is good is greater than that of the wire 3 to the joined part 2 The size L2 of the load at the time point tc when the joint state is bad. In this case, the lower limit of the reference range is set to a value larger than the magnitude L2 of the load and smaller than the magnitude L1 of the load. In addition, the upper limit of the reference range is set to a value larger than the magnitude L1 of the load.

FIGS. 9( a ) and 9 ( b ) are explanatory diagrams showing still another example of the calculation method of the determination value. FIG. 9( a ) shows the load signal waveform when the bonding state of the lead wire 3 to the bonded portion 2 is good. On the other hand, FIG.9(b) shows the load signal waveform of the case where the bonding state of the lead wire 3 with respect to the to-be-joined part 2 is bad.

As shown in FIG. 9( a ) and FIG. 9( b ), the determination value may be, for example, a load signal detected by the load cell 40 during the period after the lead wire 3 comes into contact with the joined portion 2 until the ultrasonic vibration is generated The time differential value of the load at any point in the waveform.

In the example of FIG.9(a) and FIG.9(b), the arbitrary time point td is an arbitrary time point in the period from the time point t1 to the time point t2. In FIGS. 9( a ) and 9( b ), the time differential value of the load at the time point td is shown as the slope of the tangent B to the load signal waveform at the time point td represented by a two-dot chain line.

As shown in FIGS. 9( a ) and 9 ( b ), for example, the time differential value (the slope of the tangent B1 ) when the bonding state of the wire 3 to the joined part 2 is good is greater than that of the wire 3 to the joined part The joint state of 2 is the time differential value (the slope of the tangent line B2) of the bad situation. In this case, the lower limit of the reference range is set to a value larger than the time differential value (the slope of the tangent B2 ) and smaller than the time differential value (the slope of the tangent B1 ). In addition, the upper limit of the reference range is set to a value larger than the time differential value (the slope of the tangent line B1).

Hereinafter, the wire bonding method of the embodiment will be described. The wire bonding method of the embodiment includes a probe step, an analysis step, and an operation step. In the wire bonding method of the embodiment, for example, a probe step, an analysis step, and an operation step are repeatedly performed.

In the probing step, the load applied to the joined portion 2 is continuously detected while the lead wire 3 is brought into contact with the joined portion 2 and a load is applied. In the analysis process, the judgment value is calculated from the load detected in the probing process. In the operation process, when the judgment value calculated in the analysis process is within the predetermined reference range, in the state of applying a load to the joined part 2, ultrasonic vibration is generated to join the wire 3 to the joined part. In the joining operation of the part 2, when the judgment value calculated in the analysis step is outside the reference range, it performs an operation different from the case where the judgment value is within the reference range. Here, the term "operations that are different from the case where the judgment value is within the reference range" includes, for example, not performing the engaging operation, stopping the device after performing the engaging operation, and having conditions different from the case where the judgment value is within the reference range Engagement operations, etc. are performed. Hereinafter, the flow of each case will be described.

FIG. 10 is a flowchart showing an example of the wire bonding method of the embodiment. As shown in FIG. 10, the control part 50 lowers the joining tool 11 toward the to-be-joined part 2 of the workpiece|work 1 (step S101). The control part 50 lowers the bonding tool 11 until the wire 3 held by the bonding tool 11 comes into contact with the bonded part 2 (step S102).

When the lead wire 3 is in contact with the joined part 2, the control part 50 calculates a determination value based on the load detected by the load sensor 40 (step S103). When the determination value is calculated, the control unit 50 determines whether the determination value is within a predetermined reference range (step S104).

If the determined value is within the reference range (step S104: YES), the control unit 50 controls the position of the bonding tool 11 in the Z direction by applying a predetermined load to the bonded part 2 from the bonding tool 11, and controls the position of the bonding tool 11 from the ultrasonic wave The welding head 12 generates ultrasonic vibration, and performs the bonding operation of bonding the wire 3 to the portion to be bonded 2 (step S105 ).

When the predetermined time elapses, the control unit 50 raises the bonding tool 11 to cut the lead wire 3 (lead wire cutting) (step S106 ). When all the wire bonding is completed (step S107 : YES), the control unit 50 moves the bonding tool 11 to the origin to complete the bonding. If all wire bonding has not been completed (step S107: NO), the control unit 50 moves the bonding tool 11 to the next bonded part 2, returns to step S101, and starts the next wire bonding.

If the determination value is outside the reference range (step S104: NO), the control unit 50 stops the operation of the bonding tool 11 and the ultrasonic horn 12 without performing the bonding operation (step S108). In addition, at this time, the control unit 50 may notify that an abnormality has occurred by, for example, lighting an abnormality occurrence lamp or the like. After performing step S108, the control unit 50 may restart the operation after performing some processing (go to step S107).

In addition, in this flow, steps S101 and S102 are exploration steps, steps S103 and S104 are analysis steps, and steps S105 to S108 are operation steps.

FIG. 11 is a flowchart showing still another example of the wire bonding method of the embodiment. Since steps S201-S207 of the flowchart shown in FIG. 11 are substantially the same as steps S101-S107 of the flowchart shown in FIG. 10, the description is omitted.

In the flowchart shown in FIG. 11 , if the determination value is outside the reference range (step S204 : NO), the control unit 50 performs the joining operation (step S208 ) as in step S205 , and performs wire cutting ( Step S209). After the wire cutting is performed, the control unit 50 stops the operations of the bonding tool 11 and the ultrasonic horn 12 (step S210 ). In addition, at this time, the control unit 50 may notify that an abnormality has occurred by, for example, lighting an abnormality occurrence lamp or the like. After performing step S210, the control unit 50 may start the operation again after performing some processing (go to step S207).

In addition, in this flow, steps S201 and S202 are exploration steps, steps S203 and S204 are analysis steps, and steps S205 to S210 are operation steps.

FIG. 12 is a flowchart showing another example of the wire bonding method of the embodiment. Since steps S301 to S307 of the flowchart shown in FIG. 12 are substantially the same as steps S101 to S107 of the flowchart shown in FIG. 10, the description is omitted. In step S305, the control unit 50 performs the engaging operation under the first condition.

In the flowchart shown in FIG. 12 , if the determined value is outside the reference range (step S304 : NO), the control unit 50 performs the engaging operation under a second condition different from the first condition in the engaging operation in step S305 (step S308 ) ). After the joining operation is performed, the control unit 50 performs wire cutting in the same manner as in step S306 (step S309 ). After the wire cutting is performed, the control unit 50 determines whether or not all wire bonding is completed (step S307).

In the embodiment, after the wire cutting (step S309 ) is performed, the control unit 50 may stop the operations of the bonding tool 11 and the ultrasonic horn 12 without performing the step S307 . In addition, at this time, the control unit 50 may notify that an abnormality has occurred by, for example, lighting an abnormality occurrence lamp or the like.

In addition, in this flow, steps S301 and S302 are exploration steps, steps S303 and S304 are analysis steps, and steps S305 to S309 are operation steps.

Hereinafter, the effects of the wire bonding apparatus of the embodiment and the wire bonding method of the embodiment will be described. In the manufacturing process of a semiconductor device, a wire bonding apparatus that uses wires of thin metal wires to connect between pads serving as electrodes of a semiconductor chip and wires serving as electrodes of a lead frame or a substrate is often used. In wire bonding using such a wire bonding apparatus, generally, by moving the bonding tool in the Z direction relative to the part to be bonded, such as a pad or a wire, the wire held at the front end of the bonding tool is pressed and pressed against the part to be bonded, And it is carried out by applying ultrasonic vibration to the wire by the ultrasonic welding head.

When wire bonding is performed using such a method, a sufficient bonding strength may not be obtained between the bonded portion and the wire due to the state of the bonded portion and the like, and bonding failures such as peeling of the wire from the bonded portion may occur. In particular, in the case of bonding wires to bumps formed in parts to be bonded, there may be cases where sufficient bonding strength is not obtained between the bumps and the wires due to factors such as the height or shape of the bumps. Poor bonding such as wire peeling from bumps. It is considered that this situation is due to the fact that the height or shape of the bump is abnormal, the bonding area between the wire and the bump is reduced, or due to the deformation of the bump during bonding, a sufficient load is not applied to the bonding portion. Therefore.

Therefore, it is proposed to determine the bonding between the wire and the bonding part by detecting the poor bonding between the bonding part and the wire, such as energization or capacitance detection, or by detecting the load during bonding or the position of the bonding tool in the Z direction. A way of being good or bad. However, in these conventional methods for detecting poor bonding, since the occurrence of poor bonding is detected in the middle of the bonding operation for bonding the wire to the portion to be bonded, or after the bonding operation is completed, it is possible to find out after bonding. Products with defective joints have occurred, but the occurrence of joint failures itself cannot be suppressed. Therefore, there is a problem that the yield of the product decreases.

Therefore, in the embodiment, a load sensor 40 that continuously detects the load applied by the bonding tool 11 to the bonded part 2 is provided, and the control part, according to the contact between the wire 3 and the bonded part 2, until the superposition occurs. A determination value is calculated from the load detected by the load sensor 40 during the period until the sonic vibration, and the operations of the bonding tool 11 and the ultrasonic horn 12 are controlled based on the determination value.

Thereby, for example, it is possible to estimate the quality of the bonding state of the lead wire 3 to the bonded portion 2 before performing the bonding operation. That is, it is possible to estimate whether or not a poor engagement has occurred during the engagement operation before the engagement operation is actually performed. Therefore, when it is estimated that the bonding state of the lead wire 3 to the part to be bonded 2 is poor, an operation different from the case where the bonding state is estimated to be good (for example, the bonding operation is not performed, after the bonding operation is performed) is performed. Stop the device, or perform the joint action under different conditions, etc.), and prevent the occurrence of joint failure before it occurs.

More specifically, the control unit 50, for example, performs the bonding operation when the determination value is within the reference range, and stops the bonding tool 11 and the ultrasonic horn without performing the bonding operation when the determination value is outside the reference range. 12 actions. Thereby, the occurrence of bonding failure can be reliably suppressed, and the yield of the product can be improved.

Alternatively, the control unit 50, for example, performs the bonding operation when the determination value is within the reference range, and stops the connection between the bonding tool 11 and the ultrasonic horn 12 after performing the bonding operation when the determination value is outside the reference range. action. Thereby, the occurrence of defective bonding can be suppressed, and the yield of the product can be further improved. For example, when a change in the judgment value occurs in a good-joint product as an omen of the occurrence of poor joining, the occurrence of poor joining can be prevented by such control.

Alternatively, for example, the control unit 50 performs the engagement operation under the first condition when the determination value is within the reference range, and performs the engagement operation under the second condition different from the first condition when the determination value is outside the reference range. Thereby, the occurrence of defective bonding can be suppressed, and the yield of the product can be further improved.

As described above, according to the embodiment, there are provided a wire bonding apparatus and a wire bonding method which can suppress the occurrence of poor bonding between the part to be bonded and the wire.

Several embodiments of the present invention have been illustrated above, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in other various forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments or variations thereof are included in the scope and gist of the invention, and are included in the inventions described in the claims and their equivalents. In addition, each of the above-mentioned embodiments can be implemented in combination with each other.

1: Workpiece 2: The joined part 2a: bump 3: Wire 10: Splice head 11: Joining tools 12: Ultrasonic welding head 13: Engagement Arm 13a: Shaft 14: Drive Department 20:XY stage 30: Engage the stage 40: Load sensor 50: Control Department 100: Wire Bonding Device A: Straight line B, B1, B2: Tangent D, D1, D2: distance L1, L2: the size of the load S1, S2: time integral value Sm,Sn: area SQ: Rectangle S101～S108, S201～S210, S301～S309: Steps t1～t4,ta,tb,tc,td: time point P,p1,p2,Q,X: point X,Y,Z: direction

FIG. 1 is a schematic diagram schematically showing a wire bonding apparatus according to an embodiment. FIG. 2 is a schematic view schematically showing a part of the wire bonding apparatus of the embodiment. FIG. 3 is a graph showing an example of a load signal waveform output from a load cell during wire bonding. FIG. 4 is a graph showing yet another example of the load signal waveform output from the load cell during wire bonding. FIGS. 5( a ) and 5 ( b ) are explanatory diagrams showing an example of the calculation method of the determination value. FIGS. 6( a ) and 6( b ) are explanatory diagrams showing a variation of the calculation method of the determination value shown in FIGS. 5( a ) and 5 ( b ). FIGS. 7( a ) and 7 ( b ) are explanatory diagrams showing still another example of the calculation method of the determination value. FIGS. 8( a ) and 8( b ) are explanatory diagrams showing another example of the calculation method of the determination value. FIGS. 9( a ) and 9 ( b ) are explanatory diagrams showing still another example of the calculation method of the determination value. FIG. 10 is a flowchart showing an example of the wire bonding method of the embodiment. FIG. 11 is a flowchart showing still another example of the wire bonding method of the embodiment. FIG. 12 is a flowchart showing another example of the wire bonding method of the embodiment.

1: Workpiece

2: The joined part

10: Splice head

11: Joining tools

12: Ultrasonic welding head

13: Engagement Arm

13a: Shaft

14: Drive Department

20:XY stage

30: Engage the stage

40: Load sensor

50: Control Department

100: Wire Bonding Device

X,Y,Z: direction

Claims (13)

A wire bonding device, which generates ultrasonic vibration in a state where a wire is pressed against a part to be joined to bond the wire to the part to be joined, and includes a bonding tool for connecting the wire to the part to be joined contact and apply a load; an ultrasonic welding head that generates ultrasonic vibrations; a load sensor that continuously detects the load applied to the part to be joined from the joining tool; and a control part that controls the joining tool and the ultrasonic The operation of the sonic welding head; and the control unit analyzes the data of the load output from the load sensor during the period from the time when the wire contacts the part to be joined to the start of the ultrasonic vibration, and controls the bonding based on the analysis result. Action of the tool and the aforementioned ultrasonic welding head. The wire bonding device according to claim 1, wherein the control unit calculates the determination value based on the load detected by the load sensor during the period from the time when the wire contacts the bonded part until the ultrasonic vibration is generated, and is based on The aforementioned determination value controls the actions of the aforementioned bonding tool and the aforementioned ultrasonic welding head. The wire bonding device according to claim 2, wherein when the determination value is within a predetermined reference range, the control unit selects the ultrasonic horn from the ultrasonic welding head in a state where a load is applied to the bonded part from the bonding tool The ultrasonic vibration is generated to perform the bonding operation for bonding the wire to the bonded part. When the judgment value is outside the reference range, the bonding operation is not performed. Then, the motions of the bonding tool and the ultrasonic welding head are stopped. The wire bonding device according to claim 2, wherein when the determination value is within a predetermined reference range, the control unit selects the ultrasonic horn from the ultrasonic welding head in a state where a load is applied to the bonded part from the bonding tool The ultrasonic vibration is generated to perform the bonding operation of bonding the wire to the part to be bonded. When the judgment value is outside the reference range, after the bonding operation is performed, the bonding tool and the ultrasonic welding are performed. Head movement stopped. The wire bonding apparatus according to claim 2, wherein when the determination value is within a predetermined reference range, the control unit sends a load from the ultrasonic wave to the bonded part in a state where a load is applied to the bonded part from the bonding tool. The welding head generates the ultrasonic vibration, and the wire is bonded to the joined part under the first condition. When the judgment value is outside the reference range, the second condition is different from the first condition. Engagement action. The wire bonding apparatus of claim 5, wherein the first condition and the second condition are applied to the output of the ultrasonic vibration generated from the ultrasonic welding head, the time when the bonding operation is performed, and the bonding tool At least any one of the loads of the aforementioned joined parts is different. The wire bonding device according to any one of claims 2 to 6, wherein the determination value is sensed by the load during the period from the time when the wire is in contact with the part to be joined until the ultrasonic vibration is generated The time integral value of the load in any time interval of the load signal waveform detected by the detector. A wire bonding method, comprising: an inspection step of continuously detecting the load applied to the bonded portion while a wire is brought into contact with a portion to be bonded and applying a load; and an analysis step of The determination value is calculated by applying the load; and the operation process is performed by generating ultrasonic vibration under the condition that the load is applied to the joined part when the determination value calculated in the analysis process is within the predetermined reference range. In the bonding operation of bonding the wire to the bonded portion, when the judgment value is outside the reference range, an operation different from the judgment value calculated in the analysis step is performed when the judgment value is within the reference range. The wire bonding method of claim 8, wherein when the determination value is outside the reference range, the bonding operation is not performed in the operation step. The wire bonding method according to claim 8, wherein the detection step, the analysis step, and the operation step are repeatedly performed, and when the determination value is outside the reference range, in the operation step, the bonding operation is performed. After that, it is prohibited to carry out the next aforementioned probing process. The wire bonding method of claim 8, wherein when the judgment value is within the reference range, in the operation step, the bonding operation is performed under the first condition, and when the judgment value is outside the reference range , in the above-mentioned action steps, with The aforementioned engaging operation is performed under a second condition different from the aforementioned first condition. The wire bonding method according to claim 11, wherein the first condition and the second condition are the output of the ultrasonic vibration generated from the ultrasonic horn, the time when the bonding operation is performed, and the time applied to the bonded part. At least one of the loads is different. The wire bonding method according to any one of claims 8 to 12, wherein the determination value is an arbitrary value of a load signal waveform detected by a load cell during the period from the time when the wire is in contact with the joined part until the ultrasonic vibration is generated. The time integral value of the load in the time interval.

Images