Wire bonding apparatus, wire cutting method, and computer readable storage medium
By coordinating the bonding tools, ultrasonic transducers, and control unit of the wire bonding device, the wire end can be cut off without applying a large tensile force, thus solving the problem of wire end bending and improving bonding quality and efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- YAMAHA ROBOTICS HLDG CO LTD
- Filing Date
- 2020-12-18
- Publication Date
- 2026-06-09
Smart Images
Figure CN115315792B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to a computer-readable storage medium for a wire bonding apparatus, a wire cutting method, and a program. Background Technology
[0002] Conventionally, a wire bonding apparatus is known that electrically connects a first bonding point (e.g., a pad on a semiconductor die) to a second bonding point (e.g., a lead in a package) using wire bonding. Depending on the bonding conditions of the wire bonding apparatus, the shape of the connection portion between the lower end of the wire and the electrode pad (the second bonding point), i.e., the bonding end, sometimes does not taper. In this case, if a gripper is used to grip the wire and pull the wire end upward, a large tension is applied to the wire end, causing it to be stretched. Subsequently, after further pulling the wire end upward, it is cut off at the bonding end. At this point, the stretched wire end bounces due to the reaction force during cutting. As a result, the wire and the wire end below the gripper bend into an S-shape. When bonding to the next electrode pad using the bent wire end, poor solder ball formation due to discharge, etc., may occur. Therefore, a method for cutting the wire end that does not cause bending of the wire end has been proposed.
[0003] Existing technical documents
[0004] Patent documents
[0005] Patent Document 1: Japanese Patent No. 2723277 Summary of the Invention
[0006] The problem that the invention aims to solve
[0007] The wire bonding method disclosed in Patent Document 1 involves raising the capillary diagonally upwards from the bonding position after bonding, thereby preventing the wire tail end, which is led to the front end of the capillary, from bending. However, in this wire bonding method, if the connection portion between the lower end of the wire tail end and the electrode pad, i.e., the bonding end, is not thin enough, a large tensile force will be applied to the wire when the wire tail end is cut. In this case, the wire bonding method may cause the wire to bounce due to the reaction force when the wire tail end is cut, resulting in the wire and the wire tail end under the gripper bending into an S-shape.
[0008] Therefore, the present invention was made in view of this situation, and its purpose is to prevent the wire from being cut off without applying a large tensile force to the end of the wire, and to prevent the wire from bending when the end of the wire is cut off.
[0009] Technical means to solve the problem
[0010] An embodiment of the present invention provides a wire bonding apparatus for performing wire bonding processing. The wire bonding apparatus includes: a bonding tool for inserting a wire; an ultrasonic transducer for supplying ultrasonic vibration to the bonding tool via an ultrasonic horn; a drive mechanism for moving the bonding tool; and a control unit for controlling the wire bonding process. The control unit executes: a bonding step in which the bonding tool presses the wire, thereby bonding the wire to a bonding point; a tail-end release step in which the tail end of the wire is released from the wire bonded to the bonding point; a tension application step in which the bonding tool is raised while the wire is held to apply tension to the wire; a tension release step in which the bonding tool is lowered to release the tension applied to the wire; and a tail-end cutting step in which, after performing at least one series of steps including the tension application step and the tension release step, the bonding tool is raised to cut the tail end of the wire bonded to the bonding point.
[0011] One embodiment of the present invention provides a wire bonding method for cutting wires using a wire bonding device for wire bonding processing. The wire bonding device includes: a bonding tool for inserting a wire; an ultrasonic transducer for supplying ultrasonic vibrations to the bonding tool via an ultrasonic horn; a drive mechanism for moving the bonding tool; and a control unit for controlling the wire bonding process. The wire cutting method executes the following steps: a bonding step, where the bonding tool presses the wire to bond it to a bonding point; a tail-end release step, where the tail end of the wire is released from the bonding point; a tension application step, where the bonding tool is raised while the wire is held to apply tension to the wire; a tension release step, where the bonding tool is lowered to release the tension applied to the wire; and a tail-end cutting step, where, after at least one execution of a series of steps including the tension application step and the tension release step, the bonding tool is raised to cut the tail end of the wire from the bonding point.
[0012] An embodiment of the present invention provides a computer-readable storage medium storing a program that causes a wire bonding apparatus to perform a wire bonding process, wherein the wire bonding apparatus includes: a bonding tool for inserting a wire; an ultrasonic transducer for supplying ultrasonic vibration to the bonding tool via an ultrasonic horn; a drive mechanism for moving the bonding tool; and a control unit for controlling the wire bonding process. The program causes the wire bonding apparatus to perform: a bonding step in which the bonding tool presses the wire, thereby bonding the wire to a bonding point; a tail-end release step in which the tail end of the wire is released from the wire bonded to the bonding point; a tension application step in which the bonding tool is raised while the wire is held to apply tension to the wire; a tension release step in which the bonding tool is lowered to release the tension applied to the wire; and a tail-end cutting step in which, after performing at least once a series of steps including the tension application step and the tension release step, the bonding tool is raised to cut the tail end of the wire bonded to the bonding point.
[0013] The effects of the invention
[0014] According to the present invention, the end of the wire is not subjected to a large tensile force and cut off, thereby preventing bending of the wire when the end of the wire is cut off. Attached Figure Description
[0015] Figure 1 This is a diagram illustrating an example of the wire bonding apparatus of this embodiment.
[0016] Figure 2A This is a top view of the connecting arm.
[0017] Figure 2B This is a bottom view of the connecting arm.
[0018] Figure 3 This is an example diagram showing an overview of the testing department.
[0019] Figure 4 This is another example diagram showing the outline of the testing department.
[0020] Figure 5 This is a flowchart illustrating an example of a wire bonding method.
[0021] Figure 6A This diagram illustrates an example of the action involved in forming the solder ball.
[0022] Figure 6B This diagram illustrates an example of the action of bringing the solder ball into contact with the electrode pad.
[0023] Figure 6C This is a diagram illustrating an example of a backward motion.
[0024] Figure 6DThis is a diagram illustrating an example of the actions involved in the wire winding process.
[0025] Figure 6E This diagram illustrates an example of the action of pressing a portion of the wire bond onto the electrode pad.
[0026] Figure 6F This is an example diagram illustrating the action of releasing the batting order.
[0027] Figure 6G This is a diagram illustrating an example of the action of closing the gripper.
[0028] Figure 6H This is a diagram illustrating an example of the action of the first tension-imposing step.
[0029] Figure 6I This is a diagram illustrating an example of the action in the first tension release step.
[0030] Figure 6J This is a diagram illustrating an example of the action of imparting the second tension.
[0031] Figure 6K This is a diagram illustrating an example of the action in the second tension release step.
[0032] Figure 6L This is an example diagram showing the state where the end of the wire has been cut off.
[0033] Figure 7 This is an example of a timing diagram representing each step.
[0034] Figure 8 This is an example of a detailed timing diagram for the tension application and tension release steps.
[0035] Figure 9 This is another example of a detailed timing diagram for the tension application and tension release steps.
[0036] Figure 10 This is a diagram illustrating another example of a wire bonding method.
[0037] Explanation of symbols
[0038] 1: Wire bonding device
[0039] 10: XY drive mechanism
[0040] 12: Z-drive mechanism
[0041] 14: Support shaft
[0042] 16: Joining platform
[0043] 20: Connecting arm
[0044] 21a: Top surface
[0045] 21b: Bottom surface
[0046] 22: Arm base end
[0047] 23: Connecting Part
[0048] 24: Forearm of the arm
[0049] 25a, 25b, 25c: Slits
[0050] 26: Concave
[0051] 30: Ultrasonic speaker
[0052] 32: Horn mounting screws
[0053] 40: Joining tools
[0054] 40a: Pressing part
[0055] 41: Through hole
[0056] 42: Stringing
[0057] 42a: Wire end
[0058] 42c: Joint end
[0059] 43: Welded ball section
[0060] 44: Gripper
[0061] 50: Load sensor
[0062] 52: Preload screws
[0063] 60: Ultrasonic transducer
[0064] 70: Testing Department
[0065] 71: Power Supply Section
[0066] 72: Output Measurement Unit
[0067] 73: Judgment Department
[0068] 80: Control Department
[0069] 81: Gripper Control Unit
[0070] 82: XYZ axis control unit
[0071] 90: Joint tool position detection unit
[0072] 100, 200: Semiconductor devices
[0073] 110: Semiconductor die
[0074] 112: Electrode pads
[0075] 122: Electrode pads
[0076] 132: Operations Department
[0077] 134: Display Section
[0078] 140: Bump
[0079] D1, D2: Distance traveled
[0080] H, H1: Height
[0081] S10~S21: Steps
[0082] t1~t9, t81~t86: Time points
[0083] v: Voltage Detailed Implementation
[0084] The following describes embodiments of the present invention. In the following drawings, the same or similar constituent elements are represented by the same or similar symbols. The drawings are illustrative, and the dimensions or shapes of the parts are schematic and should not be construed as limiting the technical scope of the present invention to the described embodiments.
[0085] [Structure of wire bonding device 1]
[0086] Reference Figures 1-4 To illustrate the wire bonding device 1. Figure 1 This is a diagram showing an example of the wire bonding device 1 of this embodiment. Figure 2A This is a top view of the connecting arm 20. Figure 2B This is a bottom view of the connecting arm 20. Figure 3 This is an example diagram showing an overview of the detection unit 70. Figure 4 This is another example diagram showing the outline of the detection unit 70.
[0087] like Figure 1 As shown, 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 transducer 60, a detection unit 70, a control unit 80, and a bonding tool position detection unit 90.
[0088] The XY drive mechanism 10 is configured, for example, to be movable along the XY axis direction (the direction parallel to the mating surface). In the XY drive mechanism 10, for example, a Z drive mechanism 12 is provided that allows the mating arm 20 to move along the Z axis direction (the direction perpendicular to the mating surface).
[0089] The joining arm 20 is supported by a pivot 14 and is configured to swing freely relative to the XY drive mechanism 10. The joining arm 20 is formed as a generally rectangular parallelepiped extending from the XY drive mechanism 10 toward a joining platform 16 on which the semiconductor device 100 to be joined is placed. The joining arm 20 includes: an arm base end 22 mounted to the XY drive mechanism 10; an arm front end 24 located at the front end side (-Y direction side) of the arm base end 22 and on which an ultrasonic horn 30 is mounted; and a flexible connecting portion 23 connecting the arm base end 22 and the arm front end 24. The connecting portion 23 includes, for example, a slit 25a and a slit 25b of a predetermined width extending from the top surface 21a of the joining arm 20 toward the bottom surface 21b, and a slit 25c of a predetermined width extending from the bottom surface 21b of the joining arm 20 toward the top surface 21a. Thus, the connecting portion 23 is partially constructed as a thin-walled portion through each slit 25a, 25b, 25c, thereby allowing the front end portion 24 of the arm to flex relative to the base end portion 22 of the arm.
[0090] like Figure 1 and Figure 2B As shown, a recess 26 for accommodating an ultrasonic horn 30 is formed on the bottom surface 21b side of the joining arm 20. With the ultrasonic horn 30 housed within the recess 26, it is mounted to the front end 24 of the arm via a horn fixing screw 32. A joining tool 40 is held at the front end of the ultrasonic horn 30 protruding from the recess 26, and an ultrasonic transducer 60 for generating ultrasonic vibrations is provided within the recess 26. Ultrasonic vibrations are generated by the ultrasonic transducer 60 and transmitted to the joining tool 40 via the ultrasonic horn 30. Thus, the ultrasonic transducer 60 can impart ultrasonic vibrations to the joining object via the joining tool 40. The ultrasonic transducer 60 is, for example, a piezoelectric transducer.
[0091] Moreover, such as Figure 1 and Figure 2AAs shown, on the top surface 21a side of the joining arm 20, slits 25a and 25b are sequentially formed from the top surface 21a toward the bottom surface 21b. The upper slit 25a is wider than the lower slit 25b. A load sensor 50 is provided in the wider upper slit 25a. The load sensor 50 is fixed to the front end 24 of the arm by a preload screw 52. The load sensor 50 is arranged in a manner that it is sandwiched between the base end 22 of the arm and the front end 24 of the arm. That is, the load sensor 50 is mounted offset from the central axis of the ultrasonic horn 30 in the long side direction relative to the contact / separation direction of the joining object, between the rotation center of the joining arm 20 and the mounting surface of the ultrasonic horn 30 in the front end 24 of the arm (i.e., the front end face of the joining tool 40 side in the front end 24 of the arm). Furthermore, since the ultrasonic horn 30 holding the joining tool 40 is mounted on the front end 24 of the arm in this manner, when a load is applied to the front end of the joining tool 40 due to the reaction force from the joining object, the front end 24 of the arm flexes relative to the base end 22 of the arm, thereby allowing the load to be detected in the load sensor 50. The load sensor 50 is, for example, a piezoelectric load sensor.
[0092] The joining tool 40 is used to insert the bonding wire 42, for example, a capillary tube with an insertion hole 41. The joining tool 40 inserts the bonding wire 42 for joining into the insertion hole 41. The joining tool 40 is configured such that a portion of the bonding wire 42 can be discharged from its front end. Hereinafter, for convenience, the bonding wire 42 discharged from the front end of the joining tool 40 will be referred to as the bonding wire tail end 42a. Furthermore, a pressing part 40a for pressing the bonding wire 42 is provided at the front end of the joining tool 40. The pressing part 40a has a shape that is rotationally symmetrical about the axis of the insertion hole 41 of the joining tool 40, and has a pressing surface on the lower surface around the insertion hole 41. The joining tool 40 is replaceably mounted to the ultrasonic horn 30 by means of spring force or the like.
[0093] A gripper 44 is positioned above the engagement tool 40 and operates in conjunction with it. The gripper 44 is configured to grip (constrain) or release the wire 42 at predetermined times based on a control signal output from the gripper control unit 81. Further above the gripper 44, a wire tensioner (not shown) may also be provided. The wire tensioner is configured to insert the wire 42 and apply appropriate tension to the wire 42 during engagement.
[0094] The material of the wire bonding 42 can be appropriately selected based on factors such as ease of processing and low resistance, for example, gold (Au), aluminum (Al), copper (Cu), or silver (Ag). Furthermore, the wire bonding 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 (e.g., electrode pad 112, hereinafter referred to as the first bonding point).
[0095] The detection unit 70, for example, electrically detects whether the solder ball portion 43 formed at the tip of the bonding wire 42 of the bonding tool 40 has been grounded to the semiconductor device 100 to which it is to be bonded. Furthermore, the detection unit 70, for example, detects whether the end 42a of the bonding wire has been cut off from a predetermined bonding point (e.g., electrode pad 122, hereinafter referred to as the second bonding point) of the semiconductor device 100 based on the output of an electrical signal supplied to the bonding wire 42.
[0096] 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. The output measurement unit 72 measures the output of the electrical signal supplied by the power supply unit 71. The determination unit 73 determines, for example, whether the bonding wire 42 has made electrical contact with the semiconductor device 100 based on the measurement result of the output measurement unit 72. Figure 1 As shown, one terminal of the detection unit 70 is electrically connected to the engagement platform 16, and the other terminal is electrically connected to the gripper 44 (or spool). Figure 1 omitted)).
[0097] like Figure 3 As shown, in the detection unit 70, the power supply unit 71 may also include a DC voltage power supply. That is, when the junction of the semiconductor device 100 and the bonding platform 16 can be considered to be connected only by resistive components (for example, when they are electrically connected), the detection unit 70 can use a DC voltage signal as a predetermined electrical signal. At this time, when the solder ball portion 43 of the bonding wire 42 contacts the junction of the semiconductor device 100, an electrical short circuit is generated between the bonding platform 16 and the bonding wire 42. The detection unit 70 can determine whether the solder ball portion 43 has contacted the second junction of the semiconductor device 100, i.e., the electrode pad 122, 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 unit 70 can detect whether the wire tail end 42a has been cut off from the second junction of the semiconductor device 100.
[0098] like Figure 4As shown, the power supply unit 71 in the detection unit 70 may also include an AC voltage power supply. That is, when there is a capacitance component between the junction of the semiconductor device 100 and the bonding stage 16 (for example, when they are not electrically connected), an AC voltage signal can be used as a predetermined electrical signal. At this time, when the solder ball portion 43 of the wire bonding 42 contacts the junction of the semiconductor device 100, the capacitance value of the wire bonding device 1 will be further increased by the capacitance value of the semiconductor device 100. As a result, the capacitance value between the bonding stage 16 and the wire bonding 42 changes. Therefore, the detection unit 70 can determine whether the solder ball portion 43 has contacted the second junction of the semiconductor device 100 based on the change in capacitance value (for example, the change in output voltage v). In other words, the detection unit 70 can detect whether the wire bonding tail end 42a has been cut off from the second junction of the semiconductor device 100.
[0099] return Figure 1 The joining tool position detection unit 90 detects, for example, the position of the joining tool 40 (e.g., the position of the front end of the joining tool 40), including the position of the joining tool 40 in the Z-axis direction. The joining tool position detection unit 90 outputs information related to the detected result (hereinafter referred to as detection result information) to the control unit 80.
[0100] 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 of the gripper 44. The XYZ axis control unit 82 controls the movement of the engagement tool 40 in the X-axis, Y-axis, and Z-axis directions.
[0101] The control unit 80 is connected to various structures, including the XY drive mechanism 10, the Z drive mechanism 12, the ultrasonic horn 30 (ultrasonic transducer 60), the gripper 44, the load sensor 50, the detection unit 70, and the bonding tool position detection unit 90, to transmit and receive signals. By controlling the operation of these structures, the control unit 80 can perform a process in wire bonding that cuts the wire tail 42a in a manner that prevents the wire tail 42a from bending.
[0102] The control unit 80 raises and lowers the bonding tool 40 along the Z-axis based on the detection result information output from the bonding tool position detection unit 90. After bonding the wire 42 to the second bonding point, the control unit 80 raises the bonding tool 40 along the Z-axis, thereby applying tension to the wire 42 (hereinafter referred to as the tension application step). That is, the control unit 80 applies stress to the connection portion between the wire tail end 42a and the second bonding point. Subsequently, the control unit 80 lowers the bonding tool 40 along the Z-axis, thereby releasing the tension applied to the wire 42 (hereinafter referred to as the tension release step). That is, the control unit 80 releases the stress at the connection portion between the wire tail end 42a and the second bonding point.
[0103] The control unit 80, for example, determines the upward movement direction and height of the front end of the engagement tool 40 during the tension application step based on pre-set upward-related information (hereinafter referred to as upward information). Similarly, the control unit 80, for example, determines the downward movement direction and height of the front end of the engagement tool 40 during the tension release step based on pre-set downward-related information (hereinafter referred to as downward information). Here, the height of the front end of the engagement tool 40 refers to the distance measured from a predetermined reference point, which is not particularly limited and may, for example, be the second engagement point. Furthermore, while it has been explained above that the control unit 80 determines the height of the front end of the engagement tool 40 based on the upward or downward information, it is not limited to this. For example, the control unit 80 may also determine the movement distance of the front end of the engagement tool 40 based on the upward or downward information. Specifically, as an example, the control unit 80 may also determine the upward movement distance from the second engagement point in the Z-axis direction during the tension application step, and may also determine the downward movement distance from the endpoint of the upward movement in the tension application step in the Z-axis direction during the tension release step. For convenience, the height or distance the front end of the engagement tool 40 rises is sometimes referred to as the "amount of upward movement", and the height or distance it falls is referred to as the "amount of downward movement".
[0104] Here, the upward movement direction refers, for example, to the direction away from the second joint point, ideally the Z-axis direction. The downward movement direction refers, for example, to the direction approaching the second joint point, ideally along the upward movement direction. However, by making the upward and downward movement directions angled relative to the Z-axis direction, stress in the X-axis or Y-axis direction can be applied to the lower end of the wire-setting tail 42a. Thus, a small tensile force can be used to cut the wire-setting tail 42a as described later. Here, the starting point of the upward movement direction can be, for example, the second joint point, or a point offset from the second joint point in the XY plane. Thus, stress in the X-axis or Y-axis direction can be applied to the lower end of the wire-setting tail 42a, and therefore a small tensile force can be used to cut the wire-setting tail 42a as described later. Furthermore, the starting point of the downward movement direction can also be, for example, the end point of the tension application step. For convenience, the following description assumes that the upward and downward movement directions in the control unit 80 are set to the Z-axis direction, the starting point of the initial upward movement direction is set to the second engagement point, and the starting point of the initial downward movement direction is set to the end point of the tension application step.
[0105] Furthermore, the control unit 80 can automatically set the height or movement distance (movement amount) in the tension application and tension release steps based on the thickness of the wire 42. Specifically, the control unit 80 can set the upward movement amount to a predetermined proportion (e.g., 60%) relative to the thickness of the wire 42. The control unit 80 can also set the downward movement amount to a predetermined proportion (e.g., 30%) relative to the thickness of the wire 42. Moreover, the control unit 80 can automatically set the downward movement amount in the tension release step based on the upward information. Specifically, the control unit 80 can set the downward movement amount to a predetermined proportion (e.g., 50%) relative to the upward movement amount. Furthermore, the control unit 80 can also automatically set the upward movement amount in the tension application step and the downward movement amount in the tension release step based on the material of the wire 42, in addition to the thickness of the wire 42. Specifically, for example, the harder the material of the wire 42, the larger the upward movement amount and the smaller the downward movement amount. This is because the stronger the wire 42, the less likely it is to bend or deform even under high tension. This reduces the amount of setup work required by the operator.
[0106] Furthermore, the control unit 80 is configured, for example, that the upward movement in the tension application step is greater than the downward movement in the tension release step. Ideally, the control unit 80 repeats the tension application and tension release steps multiple times. That is, the control unit 80 is configured, for example, that the height of the tip of the joining tool 40 in the current tension application step (the second tension application step described later) is higher than the height of the tip of the joining tool 40 in the previous tension application step (the first tension application step described later). Thus, by repeatedly performing the tension application and tension release steps, the control unit 80 can gradually induce metal fatigue in the portion between the lower end (the end in the -Z-axis direction) of the wire tail 42a and the end of the wire 42 connected to the second joint point that has been compressed into a thin shape (hereinafter referred to as the joint end 42c). That is, the tensile strength of the portion between the lower end of the wire tail 42a and the joint end 42c decreases. Therefore, the wire tail 42a can be cut off from the second joint point without applying a large tensile force to this portion. In other words, by gradually thinning the connection between the wire tail end 42a and the second joint point, the wire tail end 42a can be cut off with a small tensile force at the cutting time. This prevents the wire tail end 42a from bending or deforming, thus improving the bonding quality.
[0107] Furthermore, the control unit 80, for example, stops a series of steps including the tension application step and the tension release step when the detection unit 70 detects that the wire end 42a has been cut off from the second junction of the semiconductor device 100. This allows the tension application and tension release steps to be performed with a minimum number of repetitions, thus shortening the time required for cutting off the wire end 42a. Moreover, since there is no need to set the number of tension application and tension release steps, the workload for the operator can be reduced.
[0108] The control unit 80 is connected to, for example, an operation unit 132 for inputting control information (hereinafter referred to as control information) and a display unit 134 for outputting control information. The operator uses the display unit 134 to check the screen and the operation unit 132 to input control information (such as up or down information). Furthermore, the control unit 80 is a computer device including a CPU and memory, and the memory stores pre-stored programs for performing the processing required for wire bonding. The control unit 80 is configured to perform each step of controlling the operation of the bonding tool 40 described later in the wire bonding method (e.g., including programs for causing the computer to execute each step).
[0109] [Wire bonding method]
[0110] Next, refer to Figures 5-8 The wire bonding method will be explained below. The wire bonding method is a method of wire bonding using the wire bonding device 1. Figure 5 This is a flowchart illustrating an example of a wire bonding method. Figures 6A to 6L This is a diagram illustrating an example of the actions involved in each step. Figure 7 It is a timing diagram representing each step. Figures 6A to 6L Time t1 to time t9 correspond to Figure 7 The time intervals from t1 to t9. Figure 8 This is a timing diagram illustrating a detailed example of the tension application and tension release steps.
[0111] In step S10 (time t1), as follows Figure 6A As shown, the wire bonding device 1 forms a solder ball portion 43 at the front end of the wire 42 extending from the front end of the bonding tool 40. In step S10, the gripper 44 is, for example, in an open state.
[0112] In step S11 (time t1), the wire bonding device 1 lowers the bonding tool 40 toward the electrode pad 112 of the semiconductor die 110. In step S11, the gripper 44 is, for example, in a closed state.
[0113] In step S12 (time t2), as follows Figure 6BAs shown, the wire bonding device 1 brings the solder ball portion 43 into contact with the electrode pad 112. Furthermore, the wire bonding device 1 sets the gripper 44 to the open state and initiates (ON) control of the ultrasonic vibration (first bonding step). This bonds the solder ball portion 43 to the electrode pad 112. The wire bonding device 1 raises the tip of the bonding tool 40 along the Z-axis and releases the wire 42 from the tip. In step S12, the detection unit 70 detects an electrical signal. At this time, the gripper 44 is in the open state.
[0114] In step S13 (time t3), as follows Figure 6C As shown, the wire bonding device 1 is on the opposite side from the second bonding point (here, electrode pad 122). Figure 6C The direction of the "arrow" causes the bonding wire 42 to move (reverse movement). As a result, the bonding wire 42 takes on a curved shape.
[0115] In step S14 (time t4), as Figure 6D As shown, the wire bonding device 1 bends the wire 42 toward the second bonding point while forming a wire loop (wire looping step) of the wire 42. Furthermore, the wire bonding device 1 brings a portion of the wire 42 into contact with the upper surface of the electrode pad 122. This forms a wire loop (not shown) electrically connecting the first bonding point, i.e., electrode pad 112, and the second bonding point, i.e., electrode pad 122. In step S14, the gripper 44 is in the closed state.
[0116] In step S15 (time t5), as follows Figure 6E As shown, the wire bonding device 1 presses a portion of the wire 42 onto the electrode pad 122 using the pressing part 40a of the bonding tool 40. The wire bonding device 1 controls the start of ultrasonic vibration to bond a portion of the wire 42 to the electrode pad 122 (second bonding step). At this time, a bonding end 42c, which is crushed into a thin shape, is formed at the end of the wire 42 connected to the electrode pad 122.
[0117] At time t6, such as Figure 6F As shown, the bonding device 1 raises the front end of the bonding tool 40 along the Z-axis, releasing the bonding tail end 42a from the front end (tail end release step). At this time, the gripper 44 is in the open state. The bonding tool position detection unit 90 detects the height of the front end of the bonding tool 40 and outputs information indicating the height (hereinafter referred to as height information) to the control unit 80.
[0118] Furthermore, at time t6, when the control unit 80 acquires the height information of the height representation height H1 of the engagement tool 40, it controls the Z drive mechanism 12 via the XYZ axis control unit 82 to stop the movement of the engagement tool 40. At this time, as... Figure 6FAs shown, the height of the front end of the joining tool 40 is called height H1, and the wire-punching tail end 42a is extended from the front end of the joining tool 40.
[0119] At time t7, such as Figure 6G As shown, the bonding device 1 closes the gripper 44 and holds the bonding wire 42. With the gripper 44 closed, at time t8, the bonding device 1 performs the tension application and tension release steps. Figure 7 As shown, the wire bonding device 1, for example, controls the initiation of ultrasonic vibration during the tension application and tension release steps. Referring also to the following... Figure 8 This section explains the tension application and release steps at time t8.
[0120] Step S16 ( Figure 8 In time t81), such as Figure 6H As shown, the wire bonding device 1 grips the wire 42 using the gripper 44 while raising the tip of the bonding tool 40 and the gripper 44 together along the Z-axis to a predetermined height (here, height H1+D1) (hereinafter referred to as the first tension application step). In other words, the tip of the bonding tool 40 is raised a predetermined distance (here, D1). Thus, the wire bonding device 1 can apply tension to the bonding end 42c along the Z-axis. At this time, the control unit 80, for example, when acquiring height information indicating the height of the tip of the bonding tool 40 as height H1+D1, controls the Z-drive mechanism 12 via the XYZ-axis control unit 82 to stop the movement of the bonding tool 40 (gripper 44).
[0121] Step S17 ( Figure 8 In time t82), such as Figure 6I As shown, the wire bonding device 1 lowers the wire tail end 42a along the Z-axis to a predetermined height (here, height H1+D1-D2) (hereinafter referred to as the first tension release step). In other words, the tip of the bonding tool 40 is lowered by a predetermined movement distance (here, movement distance D2). Thus, the wire bonding device 1 can release the tension applied to the bonding end 42c. At this time, the control unit 80, for example, upon acquiring height information representing the height of the tip of the bonding tool 40 (height H1+D1-D2), controls the Z-drive mechanism 12 via the XYZ-axis control unit 82 to stop the movement of the bonding tool 40 (gripper 44).
[0122] In step S18, the wire bonding device 1 sets a movement amount, which represents the height or movement distance of the bonding tool 40 relative to the first tension application step and the first tension release step, and the next tension application step (hereinafter referred to as the second tension application step) and tension release step (hereinafter referred to as the second tension release step). The wire bonding device 1 sets the movement amount for each step, for example, based on information related to the movement amount (ascent information, descent information, etc.) stored in a predetermined storage unit.
[0123] Here, the wire bonding device 1, for example, sets a height higher than the height of the first tension application step as the height of the second tension application step. Similarly, the wire bonding device 1, for example, sets a height higher than the height of the first tension release step as the height of the second tension release step. Moreover, the wire bonding device 1 may, for example, set a movement distance that is the same as the movement distance of the first tension application step and the movement distance of the first tension release step as the movement distance of the second tension application step and the movement distance of the second tension release step. Here, "the same movement distance" means, for example, a movement distance that allows for mechanical error of the wire bonding device 1 in the two movement distances.
[0124] Step S19 ( Figure 8 In time t83), such as Figure 6J As shown, in the second tension application step, the wire bonding device 1 grips the wire 42 using the gripper 44 while raising the tip of the bonding tool 40 and the gripper 44 together along the Z-axis to a predetermined height (here, height H1+2D1-D2). In other words, the tip of the bonding tool 40 is raised a predetermined distance (here, distance D1) from the end point of the first tension release step (here, height H1+D1-D2). Thus, the wire bonding device 1 can apply tension to the bonding end 42c along the Z-axis. At this time, the control unit 80, for example, upon acquiring height information representing the height of the tip of the bonding tool 40 (height H1+2D1-D2), controls the Z-drive mechanism 12 via the XYZ-axis control unit 82 to stop the movement of the bonding tool 40 (gripper 44).
[0125] Step S20 ( Figure 8 In time t84), such as Figure 6KAs shown, in the second tension release step, the wire bonding device 1 lowers the wire tail end 42a along the Z-axis to a predetermined height (here, height H1+2D1-2D2). In other words, the tip of the bonding tool 40 is lowered a predetermined distance (here, distance D2) from the end point of the second tension application step (here, height H1+2D1-D2). Thus, the wire bonding device 1 can release the tension applied to the bonding end 42c. At this time, the control unit 80, for example, upon acquiring height information representing the height of the tip of the bonding tool 40 (height H1+2D1-2D2), controls the Z-drive mechanism 12 via the XYZ-axis control unit 82 to stop the movement of the bonding tool 40 (gripper 44).
[0126] In step S21, the wire bonding device 1 determines whether the wire tail end 42a has been cut off. Specifically, if the wire bonding device 1 does not detect an electrical signal in the detection unit 70, it determines that the wire tail end 42a has been cut off (step S21: Yes). At this time, the wire bonding device 1 ends the process for cutting off the wire tail end 42a. On the other hand, if the wire bonding device 1 detects an electrical signal in the detection unit 70, it determines that the wire tail end 42a has not been cut off (step S21: No). At this time, the wire bonding device 1 transfers the process to step S18.
[0127] Furthermore, the above text, as shown at times t81 to t84, only describes the first tension application step, the second tension application step, the first tension release step, and the second tension release step, but as... Figure 8 As shown at times t85 and t86, the tension application and tension release steps are repeated until no electrical signal can be detected in the detection unit 70.
[0128] Thus, through repeated tension application and release steps, it is possible to achieve... Figure 8 The joining tool 40 is operated as shown to apply tension to the wire tail 42a in stages through multiple tension application steps, so as to avoid applying excessive tension to the wire tail 42a. As a result, the connection between the wire tail 42a and the joining point (here, the joining end 42c) gradually becomes thinner, so that at the cutting time point, the wire tail 42a can be cut off with a small tensile force.
[0129] like Figure 6L As shown, when the wire bonding device 1 is cut off at the wire tail end 42a, as... Figure 7 As shown in the diagram of the "electrical signal" (disconnected), the detection unit 70 determines that no electrical signal is detected, and ends the tension application step and the tension release step.
[0130] [Variation Example]
[0131] In the above text, the wire bonding device 1 is described as follows: Figure 8 The action of setting the same moving distance as the moving distance in the first tension application step and the moving distance in the first tension release step as shown has been described, but it is not limited to this. Figure 9 This is another example of a timing diagram illustrating the tension application and release steps. (See diagram below.) Figure 9 As shown, the wire bonding device 1 can be set, for example, to the height of the second tension application step. Figure 9 The height (H+D) is higher than the height of the first tensioning step. Figure 9 The height H is sufficient. That is, the height of the second tension release step can also be the same as the height of the first tension release step. Furthermore, the height of both the second and first tension release steps can be approximately the same as the height of the second engagement point. This simplifies the handling of the descending movement in the tension release step, thus increasing the system's processing speed.
[0132] The above description, as an example of a wire bonding method, illustrates wire bonding between two points that are to be bonded, but it is not limited to this. For example, the described embodiment can also be applied to… Figure 10 The bump bonding shown is a method of forming a bump 140 on the electrode 212 of the semiconductor device 200, which serves as a bonding point. At this time, it is possible to... Figure 5 Steps S10 to S14 are omitted from the flowchart. Furthermore, the described embodiment can also be applied, for example, to wedge engagement. In this case, it can be achieved from... Figure 5 The flowchart omits step S10 to achieve this.
[0133] In the above description, it was stated 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 also determine whether the wire tail end 42a has been cut after the second tension application step (step S19), or it may determine whether the wire tail end 42a has been cut at all times. Therefore, it is possible to determine whether the wire tail end 42a has been cut without delay, thereby reducing the operation consumed by the wire bonding device 1 in cutting the wire tail end 42a.
[0134] The above description assumes that the wire bonding device 1 closes the gripper 44 during the tension release step, but it is not limited to this. The gripper 44 can also be opened during the tension release step. This makes it easier to release the tension of the wire bonding 42.
[0135] The embodiments described through the invention can be appropriately combined, modified, or improved according to the intended use, and the invention is not limited to the embodiments described herein. It is clear from the claims that forms implementing such combinations, modifications, or improvements are also included within the technical scope of the invention.
Claims
1. A wire bonding apparatus for performing wire bonding processing, the wire bonding apparatus comprising: A joining tool having an insertion hole through which a punch wire is inserted; An ultrasonic transducer supplies ultrasonic vibrations to the joining tool via an ultrasonic horn; A drive mechanism is used to move the engagement tool; and The control unit controls the wire bonding process. The control unit performs: In the joining step, the joining tool is used to press the wire, thereby joining the wire to the joining surface of the joining point, which is the object of joining. The tail end release step involves releasing the tail end of the wire from the wire bonded to the bonding point; In the tension application step, while the wire is being held in place, the bonding tool is raised perpendicular to the bonding surface to apply tension to the wire. The tension release step involves lowering the bonding tool perpendicular to the bonding surface to release the tension applied to the wire. as well as The tail-end cutting step involves raising the joining tool and cutting the tail end of the wire from the joining point. Prior to the tail-end cutting step, the tension application step and the tension release step are performed multiple times.
2. The wire bonding device according to claim 1, wherein... The tension application step includes a first tension application step and a second tension application step performed after the first tension application step. The tension release step is performed between the first tension application step and the second tension application step. The amount of upward movement of the engagement tool in the second tension application step is greater than the amount of downward movement of the engagement tool in the tension release step.
3. The wire bonding device according to claim 2, wherein... The amount of upward movement of the joining tool in the first tension application step is the same as the amount of upward movement of the joining tool in the second tension application step.
4. The wire bonding device according to claim 2, wherein... The amount of upward movement of the engagement tool in the first tension application step is the same as the amount of downward movement of the engagement tool in the tension release step.
5. The wire bonding device according to any one of claims 1 to 4, wherein The control unit then performs the following: The first joining step involves joining the wire at the tip of the joining tool to the first joining point; and The wire bonding looping step involves, after performing the first bonding step, making the wire loop from the first bonding point toward the second bonding point, which is the bonding point.
6. The wire bonding device according to any one of claims 1 to 4, wherein The joining step includes: forming the bonding wire at the front end of the joining tool into a ball shape, and joining the ball-shaped bonding wire to the joining point.
7. The wire bonding device according to any one of claims 1 to 4, further comprising: The detection unit detects whether the end of the wire has been cut off at the joint point based on the electrical signal supplied to the clamped wire. When the control unit detects in the detection unit that the end of the wire has been cut off at the joint point, it stops executing the tension application step and the tension release step.
8. The wire bonding apparatus according to any one of claims 1 to 4, wherein the upward movement in the tension imparting step and the downward movement in the tension release step are set at a predetermined ratio relative to the thickness of the wire.
9. A method for cutting wire bonding, wherein the method is performed using a wire bonding device that performs wire bonding processing, wherein... The wire bonding device includes: A joining tool having an insertion hole through which a punch wire is inserted; An ultrasonic transducer supplies ultrasonic vibrations to the joining tool via an ultrasonic horn; A drive mechanism is used to move the engagement tool; and The control unit controls the wire bonding process. The wire cutting method is performed as follows: In the joining step, the joining tool is used to press the wire, thereby joining the wire to the joining surface of the joining point, which is the object of joining. The tail end release step involves releasing the tail end of the wire from the wire bonded to the bonding point; In the tension application step, while the wire is being held in place, the bonding tool is raised perpendicular to the bonding surface to apply tension to the wire. The tension release step involves lowering the bonding tool perpendicular to the bonding surface to release the tension applied to the wire. as well as The tail-end cutting step involves raising the joining tool and cutting the tail end of the wire from the joining point. Prior to the tail-end cutting step, the tension application step and the tension release step are performed multiple times.
10. A computer-readable storage medium storing a program that causes a wire bonding apparatus to perform a wire bonding process, wherein... The wire bonding device includes: A joining tool having an insertion hole through which a punch wire is inserted; An ultrasonic transducer supplies ultrasonic vibrations to the joining tool via an ultrasonic horn; A drive mechanism is used to move the engagement tool; and The control unit controls the wire bonding process. The procedure causes the wire bonding device to perform: In the joining step, the joining tool is used to press the wire, thereby joining the wire to the joining surface of the joining point, which is the object of joining. The tail end release step involves releasing the tail end of the wire from the wire bonded to the bonding point; In the tension application step, while the wire is being held in place, the bonding tool is raised perpendicular to the bonding surface to apply tension to the wire. The tension release step involves lowering the bonding tool perpendicular to the bonding surface to release the tension applied to the wire. as well as The tail-end cutting step involves raising the joining tool and cutting the tail end of the wire from the joining point. Prior to the tail-end cutting step, the tension application step and the tension release step are performed multiple times.