TWI824354B - Wire bonding device, wire cutting method and program - Google Patents

Abstract

A wire bonding device 1 performs wire bonding processing. The wire bonding device 1 includes: a bonding tool 40 that inserts the bonding wire 42; an ultrasonic vibrator 60 that supplies ultrasonic vibration to the bonding tool 40 through an ultrasonic horn; and a driving mechanism 12 , moving the bonding tool 40; and the control unit 80 controls the wire bonding process, and the control unit 80 executes: a bonding step, using the bonding tool 40 to press the bonding 42, thereby bonding the bonding wire 42 to the bonding point as the bonding object; The end releasing step is to release the tail end 42a of the bonding wire 42 from the bonding point. The tension applying step is to lift the bonding tool 40 while clamping the bonding wire 42 to apply tension to the bonding wire 42. The tension release step is to bond the bonding wire 42. The tool 40 is lowered to release the tension applied to the bonding wire 42; and the tail end cutting step is performed at least once. After a series of steps including a tension applying step and a tension releasing step are performed at least once, the bonding tool 40 is raised to remove the joint from the bonding point. The bonding wire 42 cuts the bonding wire tail end 42a.

Description

Wire bonding device, wire cutting method and program

The present invention relates to a wire bonding device, a wire cutting method and a program.

In the past, there has been known a wire bonding device that electrically connects a first bonding point (eg, a bonding pad of a semiconductor die) and a second bonding point (eg, a lead of a package) using wires. Depending on the bonding conditions of the wire bonding device, the shape of the bonded end portion, which is the connection portion between the lower end of the wire tail end and the electrode pad serving as the second bonding point, may not be tapered. At this time, if a gripper is used to grasp the wire and the tail end of the wire is pulled up, a large tension is applied to the tail end of the wire, so that the tail end of the wire becomes stretched. Subsequently, after further pulling up the tail end of the wire, the tail end of the wire is cut off at the joint end. At this time, the stretched tail end of the wire bounces due to the reaction force during cutting. Thereby, the wire and the tail end of the wire at the lower part of the gripper are bent into an S shape. When connecting to the next electrode pad using a bent wire end, defects such as solder ball formation due to discharge may occur. Therefore, a method for cutting the wire end without bending the wire end has been proposed. [Prior art documents] [Patent Document]

Patent Document 1: Japanese Patent No. 2723277

[Problem to be solved by the invention]

The wire bonding method disclosed in Patent Document 1 is to raise the capillary obliquely upward from the bonding position after bonding, thereby preventing the tail end of the bonding wire that is led out to the front end of the capillary from bending. However, in the wire bonding method, if the connecting portion between the lower end of the tail wire and the electrode pad, that is, the bonding end, is not thin enough, a large tensile force will be exerted on the wire when the wire tail end is cut. At this time, in the wire bonding method, the reaction force when the wire tail end is cut may cause the wire to bounce, causing the wire at the lower part of the gripper and the wire tail end to bend into an S shape.

Therefore, the present invention was made in view of this situation, and its object is to prevent the wire end from being cut by applying a large tensile force, and to prevent the wire from bending when the wire end is cut. [Means to solve the problem]

A wire bonding device of one form of the present invention performs wire bonding processing. The wire bonding device includes: a bonding tool that inserts the bonding wire; an ultrasonic vibrator that supplies ultrasonic vibration to the bonding tool through an ultrasonic horn; and a driving mechanism. moving the bonding tool; and a control unit that controls the wire bonding process, and the control unit executes a bonding step of pressing the bonding tool using the bonding tool, thereby bonding the bonding wire to a bonding point that is a bonding object; The tail end releasing step is to release the tail end of the bonding wire from the bonding wire joined to the joint point; the tension applying step is to raise the bonding tool while clamping the bonding wire to apply tension to the bonding wire; the tension releasing step is to make the bonding wire The joining tool is lowered to release the tension applied to the bonding wire; and the tail end cutting step is to raise the joining tool after performing a series of steps including the tension applying step and the tension releasing step at least once, so as to The bonding wire joined to the joint point cuts off the tail end of the bonding wire.

A wire-cutting method according to one aspect of the present invention is performed using a wire-bonding device that performs wire-bonding processing. The wire-bonding device includes a bonding tool that inserts the wire; and an ultrasonic vibrator that controls the required wires via an ultrasonic horn. The bonding tool supplies ultrasonic vibration; a driving mechanism moves the bonding tool; and a control part controls the bonding bonding process, and the bonding cutting method executes: a bonding step, using the bonding tool to press the bonding, by In this step, the bonding wire is bonded to the bonding point to be bonded; the tail end releasing step is to release the bonding wire tail end from the bonding wire bonded to the bonding point; and the tension applying step is to raise the bonding tool while holding the bonding wire. , to impart tension to the binding wire; a tension releasing step to lower the joining tool to release the tension imparted to the binding wire; and a tail end cutting step to perform at least one step including the tension imparting step and the tension releasing step. After a series of steps, the bonding tool is raised to cut off the tail end of the bonding wire from the bonding wire bonded to the bonding point.

A program of one aspect of the present invention causes a wire bonding device to perform a wire bonding process, wherein the wire bonding device includes a bonding tool that inserts the bonding wire, and an ultrasonic vibrator that supplies ultrasonic vibration to the bonding tool through an ultrasonic horn. ; A driving mechanism to move the bonding tool; and a control part to control the wire bonding process, and the program causes the wire bonding device to execute: a bonding step, using the bonding tool to press the bonding, whereby the bonding is Joining to the joining point to be joined; a tail end releasing step of releasing the tail end of the bonding wire from the bonding wire bonded to the joining point; and a tension applying step of raising the bonding tool while holding the bonding wire to clamp the bonding wire applying tension; a tension releasing step, lowering the bonding tool to release the tension given to the wire; and a tail end cutting step, after performing at least once a series of steps including the tension imparting step and the tension releasing step, The bonding tool is raised to cut off the bonding wire tail end from the bonding wire bonded to the bonding point. [Effects of the invention]

According to the present invention, a large tensile force is not applied to the tail end of the bonding wire for cutting, thereby preventing the bonding wire from bending when cutting the tail end of the bonding wire.

Embodiments of the present invention will be described below. In the description of the following drawings, the same or similar components are represented by the same or similar symbols. The drawings are illustrative, and the size or shape of each part is schematic, and the technical scope of the present invention should not be construed as being limited to the above-described embodiments.

[Structure of wire bonding device 1] The wire bonding device 1 will be described with reference to FIGS. 1 to 4 . FIG. 1 is a diagram showing an example of the wire bonding device 1 according to this embodiment. FIG. 2A is a top view of the engagement arm 20 . FIG. 2B is a bottom view of the engagement arm 20 . FIG. 3 is a diagram showing an example of the outline of the detection unit 70. FIG. 4 is a diagram showing another example of the outline of the detection unit 70 .

As shown in FIG. 1 , the wire bonding device 1 includes, for example, an XY drive mechanism 10 , a Z drive mechanism 12 , a bonding arm 20 , an ultrasonic horn 30 , a bonding tool 40 , a load sensor 50 , an ultrasonic vibrator 60 , and a detection unit 70 . The control unit 80 and the bonding tool position detection unit 90 .

The XY drive mechanism 10 is configured to be movable in the XY axis direction (direction parallel to the joint surface), for example. The XY drive mechanism 10 is provided with a Z drive mechanism 12 that can move the engagement arm 20 in the Z-axis direction (direction perpendicular to the engagement surface), for example.

The engagement arm 20 is supported by the support shaft 14 and is configured to be swingable relative to the XY drive mechanism 10 . The bonding arm 20 is formed into a substantially rectangular parallelepiped so as to extend from the XY drive mechanism 10 toward the bonding stage 16 on which the semiconductor device 100 to be bonded is placed. The joint arm 20 includes an arm base end 22 mounted on the XY drive mechanism 10 , an arm front end 24 located on the front end side (-Y direction side) of the arm base end 22 and mounted with the ultrasonic horn 30 , and a connecting arm base. The end portion 22 and the arm front end portion 24 have a flexible connecting portion 23. This connection part 23 includes, for example, slits 25a and 25b of a predetermined width extending from the top surface 21a of the joint arm 20 toward the bottom surface 21b; Seam 25c. In this way, the connecting portion 23 is partially configured as a thin portion through the slits 25a, 25b, and 25c, thereby allowing the arm front end portion 24 to flex relative to the arm base end portion 22.

As shown in FIGS. 1 and 2B , a recess 26 for accommodating the ultrasonic horn 30 is formed on the bottom surface 21 b side of the joint arm 20 . The ultrasonic horn 30 is installed in the arm front end portion 24 via the horn fixing screw 32 while being accommodated in the recessed portion 26 of the joint arm 20 . The ultrasonic horn 30 holds a bonding tool 40 at a front end protruding from the recessed portion 26 , and an ultrasonic vibrator 60 that generates ultrasonic vibration is provided in the recessed portion 26 . The ultrasonic vibration is generated by the ultrasonic vibrator 60 and transmitted to the bonding tool 40 through the ultrasonic horn 30 . Thereby, the ultrasonic vibrator 60 can impart ultrasonic vibration to the joining object via the joining tool 40 . The ultrasonic vibrator 60 is, for example, a piezoelectric vibrator.

Furthermore, as shown in FIGS. 1 and 2A , slits 25 a and 25 b are formed in order from the top surface 21 a toward the bottom surface 21 b on the top surface 21 a side of the joint arm 20 . The upper slit 25a is formed wider than the lower slit 25b. Furthermore, a load sensor 50 is provided in the wide upper slit 25a. The load sensor 50 is fixed to the arm front end portion 24 with a preload screw 52 . The load sensor 50 is disposed so as to be sandwiched between the arm base end 22 and the arm front end 24 . That is, the load sensor 50 is an ultrasonic sensor installed in the rotation center of the joint arm 20 and the arm tip 24 so as to be offset from the central axis in the longitudinal direction of the ultrasonic horn 30 toward the contact/separation direction with respect to the joint object. between the mounting surface of the horn 30 (that is, the front end surface of the arm front end portion 24 on the joining tool 40 side). Furthermore, since the ultrasonic horn 30 holding the welding tool 40 is attached to the arm distal end 24 in this manner, when a load is applied to the distal end of the welding tool 40 due to the reaction force from the welding object, the arm distal end 24 moves relative to the arm. The base end 22 flexes, so that the load can be detected by the load sensor 50 . The load sensor 50 is, for example, a piezoelectric load sensor.

The bonding tool 40 is used to insert the bonding wire 42, and is, for example, a capillary tube provided with an insertion hole 41. The bonding tool 40 inserts the bonding wire 42 for bonding into the insertion hole 41 . The bonding tool 40 is configured so that a part of the bonding wire 42 can be fed out from the front end thereof. Hereinafter, for convenience, the bonding wire 42 released from the front end of the bonding tool 40 is referred to as the bonding tail end 42a. Furthermore, a pressing portion 40 a for pressing the bonding wire 42 is provided at the front end of the bonding tool 40 . The pressing portion 40 a has a shape that is rotationally symmetrical about the axial direction of the insertion hole 41 of the bonding tool 40 , and has a pressing surface on the lower surface around the insertion hole 41 . The bonding tool 40 is replaceably mounted on the ultrasonic horn 30 by spring force or the like.

The gripper 44 is, for example, provided above the joining tool 40 and operates together with the joining tool 40 . For example, the gripper 44 is configured to grip (restrain) or release the bonding wire 42 at a predetermined timing based on a control signal output from the gripper control unit 81 . A wire tensioner (not shown) may also be provided above the gripper 44 . For example, the bonding wire tensioner is configured to insert the bonding wire 42 and apply appropriate tension to the bonding wire 42 during joining.

The material of the bonding wire 42 can be appropriately selected based on ease of processing, low resistance, etc., and for example, gold (Au), aluminum (Al), copper (Cu), or silver (Ag) can be used. Furthermore, the bonding wire 42 forms a solder ball portion 43 extending from the front end of the bonding tool 40 . The solder ball portion 43 is bonded to a predetermined bonding point (for example, the electrode pad 112 , hereafter referred to as the first bonding point).

The detection unit 70 electrically detects, for example, whether the solder ball portion 43 formed by inserting the tip of the bonding wire 42 of the bonding tool 40 is grounded to the semiconductor device 100 to be bonded. Furthermore, the detection unit 70 detects, for example, based on the output of the electrical signal supplied to the bonding wire 42 , whether the bonding wire tail end 42 a has passed from a predetermined bonding point (for example, the electrode pad 122 , hereinafter referred to as the second bonding point) of the semiconductor device 100 cut off.

The detection unit 70 includes, for example, a power supply unit 71, an output measurement unit 72, and a determination unit 73. The power supply unit 71 applies a predetermined electrical signal between the semiconductor device 100 and the bonding wire 42 , for example. The output measurement unit 72 measures the output of the electrical signal supplied from the power supply unit 71 , for example. The determination unit 73 determines whether the bonding wire 42 has electrically contacted the semiconductor device 100 based on, for example, the measurement result of the output measurement unit 72 . As shown in FIG. 1 , one terminal of the detection part 70 is electrically connected to the bonding stage 16 , and the other terminal is electrically connected to the gripper 44 (or the bobbin (omitted in FIG. 1 )).

As shown in FIG. 3 , in the detection unit 70 , the power supply unit 71 may also include a DC voltage power supply. That is, when the bonding point of the semiconductor device 100 and the bonding stage 16 can be considered to be connected only by a resistance component (for example, when they are electrically connected), the detection unit 70 can use the DC voltage signal as the predetermined telecommunication signal. No. At this time, when the solder ball portion 43 of the bonding wire 42 contacts the bonding point of the semiconductor device 100 , an electrical short circuit occurs between the bonding stage 16 and the bonding wire 42 . The detection part 70 can determine whether the solder ball part 43 has contacted the electrode pad 122 which is the second junction point of the semiconductor device 100 based on the change in the presence or absence of the electrical short circuit (for example, the change in the output voltage v). In other words, the detection part 70 can detect whether the bonding tail end 42 a has been cut off from the second bonding point of the semiconductor device 100 .

As shown in FIG. 4 , in the detection unit 70 , the power supply unit 71 may also include an AC voltage power supply. That is, when there is a capacitance component between the bonding point of the semiconductor device 100 and the bonding stage 16 (for example, when there is no electrical conduction between the two), an AC voltage signal can be used as the predetermined electrical signal. At this time, when the solder ball portion 43 of the wire bonding 42 contacts the bonding point of the semiconductor device 100 , the capacitance value of the wire bonding device 1 will be further added to the capacitance value of the semiconductor device 100 . As a result, the capacitance value between the bonding stage 16 and the bonding wire 42 changes. Therefore, the detection part 70 can determine whether the solder ball part 43 has contacted the second bonding point of the semiconductor device 100 based on the change in the capacitance value (for example, the change in the output voltage v). In other words, the detection part 70 can detect whether the bonding tail end 42 a has been cut off from the second bonding point of the semiconductor device 100 .

Returning to FIG. 1 , the welding tool position detection unit 90 detects, for example, the position of the welding tool 40 (for example, the position of the tip of the welding tool 40 ) including the position of the welding tool 40 in the Z-axis direction. The bonding tool position detection unit 90 outputs information on the detected result (hereinafter referred to as detection result information) to the control unit 80 .

The control unit 80 includes, for example, a gripper control unit 81 and an XYZ-axis control unit 82. The gripper control unit 81 controls the opening and closing operations of the gripper 44 . The XYZ axis control unit 82 controls the movement of the bonding tool 40 in the X-axis direction, the Y-axis direction, and the Z-axis direction.

The control unit 80 can communicate with the XY drive mechanism 10 , the Z drive mechanism 12 , the ultrasonic horn 30 (ultrasonic vibrator 60 ), the gripper 44 , the load sensor 50 , the detection unit 70 , and the bonding tool position detection unit 90 . The structures are connected by sending and receiving signals. By controlling the operations of these structures, the control unit 80 can perform a process of cutting the wire tail end 42a without bending the wire tail end 42a during wire bonding.

The control unit 80 raises and lowers the welding tool 40 in the Z-axis direction based on the detection result information output from the welding tool position detection unit 90 . After joining the bonding wire 42 to the second bonding point, the control unit 80 applies tension to the bonding wire 42 by raising the bonding tool 40 in the Z-axis direction (hereinafter referred to as a tension applying step). That is, the control unit 80 applies stress to the connection portion between the bonding tail end 42 a and the second bonding point. Subsequently, the control unit 80 releases the tension applied to the bonding wire 42 by lowering the bonding tool 40 in the Z-axis direction (hereinafter referred to as a tension releasing step). That is, the control part 80 releases the stress in the connection part between the wire bonding tail end 42a and the second joint point.

The control unit 80 determines the upward movement direction and height of the tip of the bonding tool 40 in the tension applying step, for example, based on preset information related to the upward movement (hereinafter referred to as upward information). Similarly, the control unit 80 determines the downward movement direction and height of the tip of the bonding tool 40 in the tension release step, for example based on preset information related to descent (hereinafter referred to as descent information). Here, the height of the front end of the joining tool 40 refers to the distance from a predetermined reference point. The predetermined reference point is not particularly limited, and may be the second joining point, for example. Furthermore, in the above description, the control unit 80 determines the height of the tip of the bonding tool 40 based on the ascending information or the descending information, but it is not limited to this. For example, the control unit 80 may determine the movement distance of the tip of the bonding tool 40 based on the ascending information or the descending information. Specifically, as an example, the control unit 80 may determine the movement distance rising from the second joint point in the Z-axis direction in the tension applying step, and may also determine the movement distance in the tension releasing step from the end point rising in the tension applying step. The moving distance downward in the Z-axis direction. Hereinafter, for convenience, the rising height or movement distance of the front end of the bonding tool 40 may be referred to as the "rising movement amount", and the descending height or movement distance may be referred to as the "descending movement amount."

Here, the upward movement direction refers to, for example, the direction away from the second joint point, and is preferably the Z-axis direction. The downward movement direction refers to, for example, a direction approaching the second joint point, and preferably a direction along the upward movement direction. However, when the upward movement direction and the downward movement direction are angled with respect to the Z-axis direction, stress in the X-axis direction or Y-axis direction can be applied to the lower end of the wire bonding tail end 42a. Thereby, a small tensile force can be used to cut off the wire tail end 42a as described later. Here, the starting point of the upward movement direction may be, for example, the second joint point, or may be a point deviated from the second joint point on the XY plane. Thereby, stress in the X-axis direction or Y-axis direction can be applied to the lower end of the wire tail end 42a, so that a small tensile force can be used to cut the wire tail end 42a as described later. Furthermore, the starting point of the downward moving direction may be, for example, the end point of the tension applying step. Hereinafter, for the sake of convenience, description will be made assuming that in the control unit 80 , the ascending movement direction and the descending movement direction are set to the Z-axis direction, and the starting point of the first ascending movement direction is set to the Z-axis direction. At the two joint points, the starting point of the first downward movement direction is set as the end point of the tension imparting step.

Furthermore, the control unit 80 may automatically set the height or movement distance (movement amount) in the tension applying step and the tension releasing step based on, for example, the thickness of the wire 42 . Specifically, the control unit 80 may set a predetermined ratio (for example, 60%) to the thickness of the bonding line 42 as the increased movement amount. The control unit 80 may set a predetermined ratio (for example, 30%) to the thickness of the bonding line 42 as the downward movement amount. Furthermore, the control unit 80 may automatically set the downward movement amount in the tension release step based on the ascending information, for example. Specifically, the control unit 80 may set a predetermined ratio (for example, 50%) to the rising movement amount as the falling movement amount. Furthermore, for example, the control unit 80 may automatically set the upward movement amount in the tension applying step and the downward movement amount in the tension releasing step based on the material of the wire 42 in addition to the thickness of the wire 42 . Specifically, for example, if the material of the bonding wire 42 is harder, the control unit 80 may set the upward movement amount to be larger and the downward movement amount to be smaller. This is because the stronger the strength of the bonding wire 42, the less bending deformation occurs even if large tension is applied. This can reduce the amount of work required by the operator for setting.

Furthermore, the control unit 80 sets, for example, such that the upward movement amount in the tension applying step is greater than the downward movement amount in the tension releasing step. Furthermore, it is desirable that the control unit 80 repeats the tension applying step and the tension releasing step multiple times, for example. That is, the control unit 80 sets, for example, such that the height of the front end of the bonding tool 40 in this tension applying step (a second tension applying step to be described later) is higher than that in the previous tension applying step (a first tension applying step to be described later). The height of the front end of the joining tool 40. Thereby, the control unit 80 repeats the tension applying step and the tension releasing step, so that the lower end (the end in the −Z axis direction) of the bonding wire tail end 42 a and the bonding wire 42 connected to the second joint point can be crushed. Metal fatigue gradually occurs in the portion between the thin-shaped end portions (hereinafter referred to as joint end portions 42c). That is, the tensile strength of the portion between the lower end of the wire bonding tail end 42a and the joint end portion 42c decreases. Thereby, the bonding tail end 42a can be cut off from the second joint point without applying a large tensile force to the portion. In other words, the connection portion between the wire tail end 42a and the second joint point is gradually thinned, and at the cutting time point, the wire tail end 42a can be cut off with a small tensile force. This prevents the bonding tail end 42a from being bent and deformed, thereby improving the bonding quality.

Furthermore, the control unit 80 may, for example, take the detection unit 70 that the bonding tail end 42 a has been cut off from the second bonding point of the semiconductor device 100 as an opportunity to stop a series of steps including the tension applying step and the tension releasing step. Thereby, the tension applying step and the tension releasing step can be performed a minimum number of times, so the time of the cutting step of the wire tail end 42a can be shortened. Furthermore, since there is no need to set the number of tension applying steps and tension releasing steps, the operator's workload can be reduced.

The control unit 80 is connected to, for example, an operation unit 132 for inputting information for control (hereinafter referred to as control information) and a display unit 134 for outputting control information. The operator uses the display unit 134 to confirm the screen, and uses the operation unit 132 to input control information (ascending information, descending information, etc.). Furthermore, the control unit 80 is a computer device including a CPU, a memory, etc., and a program for executing processing required for wire bonding is stored in the memory in advance. The control unit 80 is configured to perform each step for controlling the operation of the bonding tool 40 described in the wire bonding method described below (for example, it includes a program for causing a computer to execute each step).

[Wire bonding method] Next, the wire bonding method will be described with reference to FIGS. 5 to 8 . The wire bonding method is a wire bonding method using the wire bonding device 1 . FIG. 5 is a flowchart showing an example of the wire bonding method. 6A to 6L are diagrams showing an example of the operation of each step. FIG. 7 is a timing diagram showing each step. Time t1 to time t9 in FIGS. 6A to 6L correspond to time t1 to time t9 in FIG. 7 . FIG. 8 is a timing chart showing a detailed example of the tension applying step and the tension releasing step.

In step S10 (time t1 ), as shown in FIG. 6A , the wire bonding apparatus 1 forms the solder ball portion 43 at the tip of the bonding wire 42 extending from the tip of the bonding tool 40 . In step S10, the gripper 44 is, for example, in an open state.

In step S11 (time t1 ), the wire bonding apparatus 1 lowers the bonding tool 40 toward the electrode pad 112 of the semiconductor die 110 . In step S11, the gripper 44 is in a closed state, for example.

In step S12 (time t2), as shown in FIG. 6B , the wire bonding device 1 brings the solder ball portion 43 into contact with the electrode pad 112 . Then, the wire bonding device 1 opens the gripper 44 and performs ON control of the ultrasonic vibration (first bonding step). Thereby, the solder ball portion 43 is bonded to the electrode pad 112 . The wire bonding device 1 raises the tip of the bonding tool 40 in the Z-axis direction and releases the wire 42 from the tip. In step S12, the detection part 70 detects the electrical signal. At this time, the gripper 44 is in an open state.

In step S13 (time t3), as shown in FIG. 6C , the wire bonding device 1 performs wire bonding 42 on the side opposite to the second bonding point (here, the electrode pad 122 ) (in the direction of the “arrow” in FIG. 6C ). Action (backwards action). Thereby, the bonding wire 42 has a curved shape.

In step S14 (time t4), as shown in FIG. 6D , the wire bonding device 1 forms a wire loop of the wire 42 while bending the wire 42 toward the second bonding point (wire looping step). Furthermore, the wire bonding device 1 brings a part of the bonding wire 42 into contact with the upper surface of the electrode pad 122 . Thereby, a wire loop (not shown) is formed that electrically connects the first joint point, that is, the electrode pad 112, and the second joint point, that is, the electrode pad 122. In step S14, the gripper 44 is in a closed state.

In step S15 (time t5), as shown in FIG. 6E , the wire bonding device 1 presses a part of the bonding wire 42 to the electrode pad 122 using the pressing part 40 a of the bonding tool 40 . The wire bonding device 1 controls the activation of ultrasonic vibration and joins a part of the wire 42 to the electrode pad 122 (second bonding step). At this time, at the end of the bonding wire 42 connected to the electrode pad 122, the bonding end portion 42c is formed into a thinned shape.

At time t6, as shown in FIG. 6F, the wire bonding device 1 raises the front end of the bonding tool 40 in the Z-axis direction, and releases the wire tail end 42a from the front end (tail end release step). At this time, the gripper 44 is in an open state. The welding tool position detection unit 90 detects the height of the tip of the welding tool 40 and outputs information indicating the height (hereinafter referred to as height information) to the control unit 80 .

Furthermore, at time t6, when the control unit 80 acquires the height information indicating the height H1 of the welding tool 40, the XYZ axis control unit 82 controls the Z drive mechanism 12 to stop the operation of the welding tool 40. At this time, as shown in FIG. 6F , the height of the front end of the bonding tool 40 becomes height H1 , and the wire bonding tail end 42 a is derived from the front end of the bonding tool 40 .

At time t7, as shown in FIG. 6G , the wire bonding device 1 closes the gripper 44 and grasps the wire 42 . With the gripper 44 closed, at time t8, the wire bonding device 1 executes the tension applying step and the tension releasing step. As shown in FIG. 7 , the wire bonding device 1 controls the activation of ultrasonic vibration in, for example, a tension applying step and a tension releasing step. Hereinafter, the tension applying step and the tension releasing step at time t8 will be described with reference to FIG. 8 as well.

In step S16 (time t81 in FIG. 8 ), as shown in FIG. 6H , the wire bonding device 1 uses the gripper 44 to grip the bonding wire 42 while moving the front end of the bonding tool 40 together with the gripper 44 in the Z-axis direction. It rises to a predetermined height (herein, height H1+D1) (hereinafter referred to as the first tension imparting step). In other words, the tip of the bonding tool 40 is raised by a predetermined movement distance (D1 in this case). Thereby, the wire bonding device 1 can apply tension to the bonding end portion 42c in the Z-axis direction. At this time, for example, when the control unit 80 acquires the height information indicating the height H1 + D1 of the front end of the welding tool 40 , the control unit 80 controls the Z drive mechanism 12 through the XYZ axis control unit 82 to stop the welding tool 40 (gripper 44 ) action.

In step S17 (time t82 in FIG. 8 ), as shown in FIG. 6I , the wire bonding device 1 lowers the wire tail end 42 a in the Z-axis direction until it reaches a predetermined height (herein, height H1 + D1 - D2) (hereinafter referred to as height H1 + D1 - D2 ). Do the first tension release step). In other words, the tip of the bonding tool 40 is lowered by a predetermined movement distance (here, the movement distance D2). Thereby, the wire bonding device 1 can release the tension applied to the bonding end portion 42c. At this time, for example, when the control unit 80 acquires the height information indicating the height H1 + D1 - D2 of the front end of the welding tool 40 , the control unit 80 controls the Z drive mechanism 12 through the XYZ axis control unit 82 to stop the welding tool 40 (gripping). 44) action.

In step S18, the wire bonding device 1 sets, for example, a movement amount indicating the next tension application step (hereinafter referred to as the second tension application step) and the tension with respect to the first tension application step and the first tension release step. The height or movement distance of the engagement tool 40 for each release step (hereinafter referred to as the second tension release step). The wire bonding device 1 sets the movement amount of each step based on, for example, information on the movement amount (ascent information, descent information, etc.) stored in a predetermined storage unit.

Here, the wire bonding device 1 sets a height higher than the height of the first tension applying step as the height of the second tension applying step, for example. Similarly, the wire bonding device 1 sets a height higher than the height of the first tension release step as the height of the second tension release step, for example. Furthermore, the wire bonding device 1 may, for example, set the same moving distance as the moving distance of the first tension applying step and the moving distance of the first tension releasing step as the moving distance of the second tension applying step and the second tension releasing step. Moving distance. Here, the “same moving distance” means, for example, a moving distance that allows for a mechanical error of the wire bonding device 1 among the two moving distances.

In step S19 (time t83 in FIG. 8 ), as shown in FIG. 6J , the wire bonding device 1 uses the gripper 44 to grip the bonding wire 42 in the second tension applying step, while moving the front end of the bonding tool 40 to the gripper. The holder 44 rises along the Z-axis direction together until it reaches a predetermined height (here, height H1+2D1-D2). In other words, the tip of the bonding tool 40 is raised by a predetermined movement distance (here, the movement distance D1 ) from the end point of the first tension release step (here, the height H1 + D1 - D2 ). Thereby, the wire bonding device 1 can apply tension to the bonding end portion 42c in the Z-axis direction. At this time, for example, when the control unit 80 acquires the height information indicating the height H1+2D1-D2 of the front end of the welding tool 40, the control unit 80 controls the Z drive mechanism 12 through the XYZ axis control unit 82 to stop the welding tool 40 (gripping). 44) action.

In step S20 (time t84 in FIG. 8 ), as shown in FIG. 6K , the wire bonding device 1 lowers the wire tail end 42 a along the Z-axis direction to a predetermined height (here, height H1 + 2D1-2D2). In other words, the tip of the bonding tool 40 is lowered by a predetermined movement distance (here, movement distance D2) from the end point of the second tension applying step (here, height H1+2D1-D2). Thereby, the wire bonding device 1 can release the tension applied to the bonding end portion 42c. At this time, for example, when the control unit 80 acquires the height information indicating the height H1+2D1-2D2 of the front end of the welding tool 40, the control unit 80 controls the Z drive mechanism 12 through the XYZ axis control unit 82 to stop the welding tool 40 (gripping). 44) action.

In step S21, the wire bonding device 1 determines whether the wire tail end 42a has been cut. Specifically, when the detection unit 70 does not detect an electrical signal, the wire bonding device 1 determines that the wire tail end 42 a has been cut (step S21 : YES). At this time, the wire bonding device 1 ends the process of cutting the wire tail end 42a. On the other hand, when the detection unit 70 detects the electrical signal, the wire bonding device 1 determines that the wire tail end 42 a has not been cut (step S21 : NO). At this time, the wire bonding apparatus 1 shifts the process to step S18.

Furthermore, in the above, only the first tension applying step, the second tension applying step, the first tension releasing step, and the second tension releasing step have been described as shown from time t81 to time t84. However, time t85 and time t85 in FIG. 8 As indicated by t86, the tension applying step and the tension releasing step are repeated until the detection unit 70 detects no electrical signal.

In this way, by repeating the tension applying step and the tension releasing step, the bonding tool 40 can be operated as shown in FIG. 8 to apply tension to the wire tail end 42a in stages through multiple tension applying steps to avoid damaging the wire. The tail end 42a exerts excessive tension. Thereby, the connection portion between the wire end 42a and the joint point (here, the joint end 42c) is gradually thinned, so that at the cutting time point, the wire end 42a can be cut with a small tensile force.

As shown in FIG. 6L , when the wire tail end 42 a of the wire bonding device 1 is cut off, as shown in the graph (disconnection) of the “electrical signal” shown in FIG. 7 , the detection unit 70 determines that it is not detected. When the electrical signal is detected, the tension imparting step and the tension releasing step are completed.

[Modification] In the above, the operation of the wire bonding device 1 to set the same moving distance as the moving distance in the first tension applying step and the moving distance in the first tension releasing step as shown in FIG. 8 has been described, but it is not limited thereto. FIG. 9 is a timing chart showing another example of the tension applying step and the tension releasing step. As shown in FIG. 9 , for example, the wire bonding device 1 only needs to be set so that the height of the second tension applying step (height H+D in FIG. 9 ) is higher than the height of the first tension applying step (height H in FIG. 9 ). . That is, the height of the second tension releasing step may be the same as the height of the first tension releasing step. Furthermore, the height of the second tension releasing step and the height of the first tension releasing step may also be substantially the same height as the second joint point. Thereby, the processing of the descending movement amount in the tension release step is simplified, so the processing speed of the system is increased.

In the above, as an example of the wire bonding method, wire bonding in which two points to be bonded are connected by wire has been described, but the method is not limited to this. For example, the above-described embodiment may be applied to a method of forming the bumps 140 on the electrodes 212 serving as the bonding points of the semiconductor device 200 in the bump bonding shown in FIG. 10 . At this time, the steps from step S10 to step S14 can be omitted from the flowchart of FIG. 5 and implemented. Furthermore, for example, the above-described embodiment may be applied to wedge joining. At this time, the step S10 can be omitted from the flowchart of FIG. 5 and implemented.

The description above assumes that the wire bonding device 1 determines whether the wire tail end 42a has been cut after the second tension release step (step S20), but it is not limited to this. The wire bonding device 1 may determine whether the wire tail end 42a has been cut after the second tension applying step (step S19), or may always determine whether the wire tail end 42a has been cut. Thereby, it can be determined without delay whether the bonding tail end 42a has been cut, and therefore the action required for cutting the bonding tail end 42a of the wire bonding device 1 can be reduced.

The above description has been made assuming that the wire bonding device 1 closes the gripper 44 in the tension release step, but it is not limited to this. During the tension release step, the gripper 44 can also be opened. This makes it easier to release the tension of the binding thread 42 .

The implementation forms described through the embodiments of the invention can be appropriately combined according to the purpose, or used with modifications or improvements, and the present invention is not limited to the description of the embodiments. It is clear from the description of the claimed scope that embodiments in which such combinations, changes, or improvements are made are also included in the technical scope of the present invention.

1:Wire bonding device 10:XY drive mechanism 12:Z drive mechanism 14: Pivot 16:Join the carrier 20:joint arm 21a:Top surface 21b: Bottom surface 22:Arm base end 23:Connection Department 24: Front end of arm 25a, 25b, 25c: slit 26: concave part 30:Ultrasonic speaker 32: Speaker fixing screw 40:Joining tools 40a: Compression part 41:Insert hole 42:Threading 42a:Tail end of wire 42c:joined end 43: Solder ball part 44:Grapple 50:Load sensor 52: Screws for preloading 60: Ultrasonic vibrator 70:Testing Department 71:Power supply department 72: Output measurement part 73: Judgment Department 80:Control Department 81: Gripper control part 82:XYZ axis control part 90:Joining tool position detection part 100, 200: Semiconductor devices 110:Semiconductor grain 112:Electrode pad 122:Electrode pad 132:Operation Department 134:Display part 140: Bump D1, D2: moving distance H, H1: height S10～S21: steps t1～t9, t81～t86: time v: voltage

FIG. 1 is a diagram showing an example of the wire bonding device according to this embodiment. Figure 2A is a top view of the engagement arm. Figure 2B is a bottom view of the engagement arm. FIG. 3 is a diagram showing an example of the outline of a detection unit. FIG. 4 is a diagram showing another example of the outline of the detection unit. FIG. 5 is a flowchart showing an example of the wire bonding method. FIG. 6A is a diagram showing an example of an operation for forming a solder ball portion. FIG. 6B is a diagram showing an example of the operation of bringing the solder ball portion into contact with the electrode pad. FIG. 6C is a diagram showing an example of the backward movement. FIG. 6D is a diagram showing an example of the operation of the wire wrapping step. FIG. 6E is a diagram showing an example of the operation of pressing a part of the bonding wire to the electrode pad. FIG. 6F is a diagram showing an example of the operation of releasing the wire. FIG. 6G is a diagram showing an example of the operation of closing the gripper. FIG. 6H is a diagram showing an example of the operation of the first tension applying step. FIG. 6I is a diagram showing an example of the operation of the first tension releasing step. FIG. 6J is a diagram showing an example of the operation of the second tension applying step. FIG. 6K is a diagram showing an example of the operation of the second tension release step. FIG. 6L is a diagram showing an example of a state in which the tail end of the bonding wire is cut. FIG. 7 is an example of a timing diagram showing each step. FIG. 8 is an example of a detailed timing chart of the tension applying step and the tension releasing step. FIG. 9 is another example of a detailed timing chart of the tension applying step and the tension releasing step. FIG. 10 is a diagram showing another example of the wire bonding method.

1:Wire bonding device

10:XY drive mechanism

12:Z drive mechanism

14: Pivot

16:Join the carrier

20:joint arm

21a:Top surface

21b: Bottom surface

22:Arm base end

23:Connection Department

24: Front end of arm

25a, 25b, 25c: slit

26: concave part

30:Ultrasonic speaker

32: Speaker fixing screw

40:Joining tools

40a: Compression part

41:Insert hole

42:Threading

43: Solder ball part

44:Grapple

50:Load sensor

52: Screws for preloading

60: Ultrasonic vibrator

70:Testing Department

71:Power supply department

72: Output measurement part

73: Judgment Department

80:Control Department

81: Gripper control part

82:XYZ axis control part

90:Joining tool position detection part

100:Semiconductor device

110:Semiconductor grain

112:Electrode pad

122:Electrode pad

132:Operation Department

134:Display part

Claims (10)

A wire bonding device performs wire bonding processing, and the wire bonding device includes: Joining tools, inserting and wiring; An ultrasonic vibrator provides ultrasonic vibration to the bonding tool through an ultrasonic horn; a drive mechanism to move the engagement tool; and a control unit that controls the wire bonding process, The control unit executes: The bonding step is to use the bonding tool to press the bonding wire, thereby bonding the bonding wire to the bonding point as the bonding object; The step of releasing the tail end is to release the tail end of the wire from the wire bonded to the joint point; The step of applying tension is to raise the bonding tool while clamping the bonding wire to apply tension to the bonding wire; a tension release step to lower the bonding tool to release the tension imparted to the bonding wire; and In the tail end cutting step, after performing a series of steps including the tension applying step and the tension releasing step at least once, the bonding tool is raised to cut the bonding wire tail from the bonding wire bonded to the bonding point. end. The wire bonding device according to claim 1, wherein In the tail end cutting step, the control unit executes a series of steps including the tension applying step and the tension releasing step multiple times. The wire bonding device according to claim 2, wherein The tension imparting step includes a first tension imparting step and a second tension imparting step performed after the first tension imparting step, The tension releasing step is performed between the first tension imparting step and the second tension imparting step, The upward movement amount of the joining tool in the second tension applying step is greater than the downward movement amount of the joining tool in the tension releasing step. The wire bonding device according to claim 3, wherein The upward movement amount of the bonding tool in the first tension applying step is the same as the upward movement amount of the bonding tool in the second tension applying step. The wire bonding device according to claim 3, wherein The upward movement amount of the joining tool in the first tension applying step is the same as the downward movement amount of the joining tool in the tension releasing step. The wire bonding device according to any one of claims 1 to 5, wherein The control unit then executes: The first joining step is to join the wire bonding at the front end of the joining tool to the first joining point; and In the step of wire binding and looping, after performing the first joining step, the wire is looped from the first joining point toward the second joining point serving as the joining point. The wire bonding device according to any one of claims 1 to 5, wherein The bonding step includes forming the bonding wire at the front end of the bonding tool into a spherical shape, and bonding the spherical bonding wire to the bonding point. The wire bonding device as described in any one of claims 1 to 5, further includes: a detection unit that detects that the tail end of the bonding wire has been cut off at the joint point based on an electrical signal supplied to the clamped bonding wire, The control part stops a series of steps including the tension applying step and the tension releasing step when the detection part detects that the wire tail end has been cut off at the joint point. A wire cutting method is performed using a wire bonding device that performs wire bonding processing, wherein The wire bonding device includes: Joining tools, inserting and wiring; An ultrasonic vibrator provides ultrasonic vibration to the bonding tool through an ultrasonic horn; a drive mechanism to move the engagement tool; and a control unit that controls the wire bonding process, The wire cutting method is executed as follows: The bonding step is to use the bonding tool to press the bonding wire, thereby bonding the bonding wire to the bonding point as the bonding object; The step of releasing the tail end is to release the tail end of the wire from the wire bonded to the joint point; The step of applying tension is to raise the bonding tool while clamping the bonding wire to apply tension to the bonding wire; a tension release step to lower the bonding tool to release the tension imparted to the bonding wire; and In the tail end cutting step, after performing a series of steps including the tension applying step and the tension releasing step at least once, the bonding tool is raised to cut the bonding wire tail from the bonding wire bonded to the bonding point. end. A program that causes a wire bonding device to perform wire bonding processing, wherein The wire bonding device includes: Joining tools, inserting and wiring; An ultrasonic vibrator provides ultrasonic vibration to the bonding tool through an ultrasonic horn; a drive mechanism to move the engagement tool; and a control unit that controls the wire bonding process, The program causes the wire bonding device to execute: The bonding step is to use the bonding tool to press the bonding wire, thereby bonding the bonding wire to the bonding point as the bonding object; The step of releasing the tail end is to release the tail end of the wire from the wire bonded to the joint point; The step of applying tension is to raise the bonding tool while clamping the bonding wire to apply tension to the bonding wire; a tension release step to lower the bonding tool to release the tension imparted to the bonding wire; and In the tail end cutting step, after performing a series of steps including the tension applying step and the tension releasing step at least once, the bonding tool is raised to cut the bonding wire tail from the bonding wire bonded to the bonding point. end.

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