Multi-directional ultrasonic bonding method and system

Abstract

The embodiments of the present application relate to the field of semiconductor processing technology, especially a multi-directional ultrasonic bonding method and system. The method and system include and perform the following steps: constructing a UVZ driving module for driving a bonding tool based on an XY platform, wherein the UVZ driving module includes at least a U-axis motion unit and a V-axis motion unit for high-frequency motion; generating ultrasonic parameters; according to the ultrasonic parameters, calling the U-axis motion unit and the V-axis motion unit of the UVZ driving module to drive the bonding tool for high-frequency vibration individually or together during bonding processing. To achieve high-frequency vibration in a single direction of the driving bonding tool, the high-frequency vibration of the driving bonding tool in any direction and any path within the vibration range can also be achieved by controlling the motion amplitude and phase angle difference of the U-axis motion unit and the V-axis motion unit, and the traditional one-dimensional ultrasonic vibration is expanded into a two-dimensional vector ultrasonic vibration, which greatly improves the bonding quality and bonding efficiency.

Description

Technical Field

[0001] The embodiments of the present application relate to the field of semiconductor processing technology, and in particular to a multi-directional ultrasonic bonding method and system. Background Art

[0002] Wire bonding is an important process in the semiconductor packaging process. Its principle is to bond the two ends of the metal wire to the chip pad and the bracket pin respectively through the wire bonding equipment, so as to achieve signal conduction between the chip and the bracket. During bonding, the transducer on the bonding tool of the wire bonding equipment outputs ultrasonic waves and applies a certain pressure to make the metal wire closely contact with the chip pad and vibrate and rub. Under the action of high temperature and time, the metal wire and the chip pad are bonded.

[0003] In the existing technology, the ultrasonic vibration direction output by the bonding head of the wire bonding equipment is usually only in the single Y direction, that is, front and back vibration. For diversified packaging products, single-direction ultrasonic vibration bonding has great limitations, such as Figure 1 As shown in the figure, a single Y-direction ultrasonic vibration on the solder joint a1 on the chip pad a is not conducive to the control of the spherical shape. Increasing the ultrasonic force is likely to cause defects such as elliptical balls or eccentric balls. For example, when the chip pad a is an aluminum electrode a2, the Y-direction ultrasonic vibration bonding will cause severe aluminum extrusion in the Y direction, reducing the reliability of the bonding. If the aluminum layer of the chip is very thin, severe aluminum extrusion in the Y direction will also cause crater problems, that is, the plating layer under the aluminum layer is damaged, causing chip failure, and too much aluminum extrusion will accidentally touch the PN line a3, causing the chip to short-circuit. When a single Y-direction ultrasonic vibration is performed on the solder joint b1 of the lead frame b, when the wire bonding direction is in the Y direction, such as Figure 2 As shown, the ultrasonic vibration in the Y direction will cause the solder joint b1 to fail to expand and have insufficient width when bonding the solder joint b1, thereby reducing the bonding reliability. If a non-horizontal wire bonding direction is encountered, the ultrasonic vibration in the Y direction will cause the solder joint b2 to have a poor solder joint and an asymmetric appearance, thereby reducing the bonding reliability.

[0004] In the prior art, in order to make up for the above-mentioned limitations brought about by single Y-direction ultrasonic vibration, a grinding method is adopted to assist ultrasonic vibration, that is, a small movement is performed by the traditional XY platform linear motor while ultrasonic output is in progress to enhance bonding. Since the XY platform has a large load and a large moment of inertia, the grinding frequency generally does not exceed 250Hz due to structural limitations, which is far from the ultrasonic frequency. Therefore, the grinding process takes a long time. After turning on the grinding function, the entire bonding time is at least doubled, which greatly reduces the bonding efficiency of the machine. Summary of the invention

[0005] On the first aspect, the embodiments of the present application provide a multi-directional ultrasonic bonding method that can solve the problems of existing wire bonding equipment that can only perform ultrasonic vibration in a single direction in the Y direction and the bonding reliability defects and low bonding efficiency existing in the combined grinding method.

[0006] The method comprises the following steps:

[0007] A UVZ driving module for driving a bonding tool is constructed based on an XY platform, wherein the UVZ driving module includes at least a U-axis motion unit and a V-axis motion unit for performing high-frequency motion;

[0008] generating ultrasound parameters, wherein the ultrasound parameters include an ultrasound path;

[0009] According to the ultrasonic parameters, during bonding processing, the U-axis motion unit and the V-axis motion unit of the UVZ driving module are called to drive the bonding tool to vibrate at high frequency individually or together.

[0010] Due to the adoption of the above method, high-frequency vibration of the bonding tool in a single direction can be achieved through separate control of the U-axis motion unit and the V-axis motion unit. High-frequency vibration of the bonding tool in any direction and any path within the vibration range can be achieved by controlling the motion amplitude and phase difference of the U-axis motion unit and the V-axis motion unit. The one-dimensional ultrasonic vibration on the traditional bonding surface is expanded into a two-dimensional vector ultrasonic vibration, which greatly expands the richness of bonding process development and greatly improves the bonding quality and bonding efficiency.

[0011] In a possible implementation, the UVZ driving module includes:

[0012] A U-axis motion unit, comprising a U-axis voice coil motor and a U-axis body, wherein the U-axis voice coil motor comprises a U-axis stator and a U-axis mover, wherein the U-axis mover moves horizontally in a U-axis direction relative to the U-axis stator, the U-axis stator is disposed on the mounting seat, and the U-axis mover is connected to the U-axis body;

[0013] A V-axis motion unit, comprising a V-axis voice coil motor and a V-axis body, wherein the V-axis voice coil motor comprises a V-axis stator and a V-axis mover, wherein the V-axis mover moves horizontally in a V-axis direction relative to the V-axis stator, wherein the V-axis stator is disposed on the mounting seat, and the V-axis mover is connected to the V-axis body;

[0014] The U-axis motion unit and the V-axis motion unit move individually or simultaneously by means of mechanical decoupling or electromagnetic decoupling.

[0015] In a possible implementation, the UVZ driving module further includes:

[0016] A Z-axis motion unit, comprising a Z-axis voice coil motor and a Z-axis body, wherein the Z-axis voice coil motor comprises a Z-axis stator and a Z-axis mover, wherein the Z-axis mover moves vertically in a Z-axis direction relative to the Z-axis stator, and the Z-axis mover is connected to the Z-axis body;

[0017] The bonding tool is mounted on the Z-axis body.

[0018] In a possible implementation, the step of generating ultrasound parameters further includes:

[0019] Generate ultrasonic path for chip pad and generate ultrasonic path for lead standoff.

[0020] In a possible implementation, the ultrasonic direction of the chip pad is generated by controlling the U-axis motion unit and the V-axis motion unit to work simultaneously to perform high-frequency vibration on a circular path.

[0021] In a possible implementation, generating the ultrasonic direction of the lead support further includes:

[0022] Generate the line direction for bonding process;

[0023] Obtaining the line direction of the wire bonding at the solder joint, and generating an ultrasonic vibration path perpendicular to the line direction;

[0024] When the line direction is parallel to the U-axis or V-axis direction, the U-axis motion unit and the V-axis motion unit are controlled to work in a decoupled manner to perform high-frequency vibration on a path perpendicular to the line direction;

[0025] When the line direction is inclined to the U-axis or V-axis direction, the U-axis motion unit and the V-axis motion unit are controlled to work simultaneously to perform high-frequency vibration on a path perpendicular to the line direction.

[0026] In a second aspect, an embodiment of the present application further provides a multi-directional ultrasonic bonding system, the system comprising:

[0027] A UVZ driving module, wherein the UVZ driving module comprises at least a U-axis motion unit and a V-axis motion unit for performing high-frequency motion;

[0028] An ultrasound parameter generation module, used for generating ultrasound parameters;

[0029] The ultrasonic execution control module controls the U-axis motion unit and the V-axis motion unit of the UVZ driving module to drive the bonding tool to vibrate at high frequency individually or together during bonding processing according to the ultrasonic parameters generated by the ultrasonic parameter generation module.

[0030] In a possible implementation, the ultrasonic parameter generation module includes an ultrasonic direction generation unit of a chip pad and an ultrasonic direction generation unit of a pin support.

[0031] In a possible implementation, the ultrasonic execution control module includes a U-axis motion control unit and a V-axis motion control unit, which control the U-axis motion unit and the V-axis motion unit to work separately or simultaneously to execute ultrasonic instructions. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0033] Figure 1 It is a schematic diagram of the ultrasonic bonding effect of the existing chip pad;

[0034] Figure 2 It is a schematic diagram of the ultrasonic bonding direction of the existing lead frame;

[0035] Figure 3 is a flow chart of the first embodiment;

[0036] Figure 4 A schematic diagram of a motion coordinate system constructed in accordance with the first embodiment;

[0037] Figure 5 Schematic diagram of circular path ultrasonic bonding of chip pad in the second embodiment;

[0038] Figure 6 This is an ultrasonic schematic diagram of a straight path of a lead stent in the second embodiment;

[0039] Figure 7 is a schematic structural diagram of a wire bonding device according to a third embodiment;

[0040] Figure 8 It is a schematic structural diagram of the wire bonding device of the third embodiment from another perspective;

[0041] Fig. 9 for Figure 7 A in the enlarged view;

[0042] Fig.10 FIG. 4 is a schematic diagram of the system composition structure of the fourth embodiment. DETAILED DESCRIPTION

[0043] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described in detail by way of implementation methods with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, but not all of the embodiments. In the absence of conflict, the embodiments in the present application and the features in the embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0044] It should be noted that: in the accompanying drawings, the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions; in the description of the present application, the terms "center", "longitudinal", "lateral", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as limiting the scope of protection of the present application; in the description of the present application, "first", "second", etc. are only used to distinguish elements of the same type from each other, rather than to indicate their importance and order, etc.

[0045] In order to make the role of ultrasonic vibration in the following embodiments more clear, the specific process content of the bonding process and the role of ultrasonic vibration in the process are briefly explained here. At the same time, the role and basic principles of the technical names involved in the principle description of the following embodiments are described.

[0046] In the manufacturing process of semiconductor devices, it is necessary to connect the pins of the lead frame with the pads of the semiconductor chip installed on the lead frame through a wire bonding device. This type of processing is generally called bonding processing. The bonding process is performed by a bonding tool. The bonding tool generally includes a wedge tool, a splitter or a similar structure. The metal wire is pulled and hot-pressed to bond the pads of the lead frame and the corresponding semiconductor chip pins to achieve the connection between the pads and the pins of the semiconductor chip. During welding, the end of the metal wire is irradiated by plasma to make it molten spherical, also known as a "solder ball". In order to make the solder ball firmly welded to the chip pad and the solder joint on the silver wire frame, when the bonding tool carries the solder ball to contact the solder joint, it is generally necessary to vibrate the bonding tool in one direction through ultrasonic vibration so that the metal wire is stably fixed on the solder joint. The existing ultrasonic vibration is driven by a transducer, also called an ultrasonic transducer. The working principle of the ultrasonic transducer is mainly based on the piezoelectric effect. The piezoelectric effect refers to the fact that certain crystals or ceramic materials will generate corresponding electrical signals when subjected to mechanical pressure or tension; conversely, they will also generate mechanical vibrations when subjected to electrical signals. Ultrasonic transducers use this piezoelectric effect to convert electrical signals into mechanical vibrations, thereby generating ultrasonic waves. Specifically, when the electrical signal passes through the piezoelectric material of the transducer, the piezoelectric material will deform, thereby generating mechanical vibrations, which are transmitted to the external environment through the matching layer to form ultrasonic waves. Installing the transducer on the bonding tool can drive the bonding tool to vibrate ultrasonically in one direction, and this ultrasonic vibration will bring about many of the problems mentioned above, which will not be repeated here.

[0047] The first embodiment of the present application provides a multi-directional ultrasonic bonding method, such as Figure 3 As shown, the method comprises the steps of:

[0048] S1. A UVZ drive module for driving a bonding tool is constructed based on an XY platform, wherein the UVZ drive module includes at least a U-axis motion unit and a V-axis motion unit for high-frequency motion;

[0049] In step S1, the motion platform of the existing bonding processing equipment needs to be reconstructed. The existing bonding processing equipment drives the bonding tool to move and work through the XYZ motion platform, and drives the bonding work to move in the horizontal direction through the XY platform to pull the metal wire to move between the solder joints. The Z-axis assembly is used to install the bonding tool and drive the bonding tool to move in the vertical direction to realize the vertical movement in the bonding process.

[0050] like Figure 4As shown, the UVZ driving module for driving the bonding tool based on the XY platform in this step S1 is to further superimpose a driving module that can move in three directions of UV and Z on the basis of the existing XY platform, wherein the U direction is parallel to the X direction of the XY platform, that is, the left-right direction, horizontal left-right direction, etc., the V direction is parallel to the Y direction of the XY platform, that is, the front-back direction, horizontal front-back direction, etc., and the Z direction is the vertical direction, that is, the up-down direction, vertical direction, etc.

[0051] Since the high-frequency ultrasonic vibration that needs to be achieved in this embodiment needs to at least achieve high-speed reciprocating motion in the horizontal direction, the UVZ drive module in this embodiment includes at least a U-axis motion unit and a V-axis motion unit for high-frequency motion. This does not mean that the UVZ drive module in this embodiment does not have relevant settings for driving the bonding tool to move in the vertical direction.

[0052] In this embodiment, the UVZ drive module performs a small range and short distance movement in the U-axis direction and the V-axis direction, so that the UVZ drive module has a small movement range and a low movement load, which can greatly reduce the inertia of the drive device during movement, and greatly improve the acceleration of the bonding mechanism during movement. It can not only perform a small range of spatial movement on the bonding processing station, but also assist the existing transducer during ultrasonic bonding to achieve multi-directional and multi-path ultrasonic vibrations that the existing transducers cannot achieve, or in some cases, the U-axis motion unit and the V-axis motion unit cooperate to achieve simulated ultrasonic vibrations of a specific path.

[0053] The high-frequency motion described in this embodiment refers to the reciprocating motion that can reach or exceed the medium and high frequency sound wave vibration frequency. In order to realize the driving of high-frequency motion and the connection with the driven parts, the U-axis motion unit and the V-axis motion unit generally need to include a high-frequency drive motor and a transmission structure connected to the drive end of the high-frequency drive motor.

[0054] S2. Generate ultrasound parameters;

[0055] The generation of ultrasonic parameters can be carried out by accepting manual input through the input device, or by automatic recognition of the bonding area through a visual mechanism. In the bonding equipment in this field, generating a work path through visual recognition is a relatively mature technology. By imaging the chip pads and pin brackets through a visual recognition mechanism, the path and process of the bonding process can be automatically analyzed and generated. In this process, the residence time of the bonding tool at each solder joint can be generated by identifying the solder joints and generating the welding process. Further, the ultrasonic process and related parameters can be inserted in this time period.

[0056] Ultrasonic parameters generally include multiple parameters, including ultrasonic intensity and ultrasonic time. The settings of these parameters can be the same as those of conventional ultrasonic parameters. In this embodiment, due to the construction of the UVZ driving module in step S1, the ultrasonic path can also be set and generated as an ultrasonic parameter through the high-frequency motion U-axis motion unit and V-axis motion unit of the UVZ driving module, so the generation of the ultrasonic path is further described in detail. Of course, the ultrasonic path as an ultrasonic parameter can also be manually set or generated through visual recognition.

[0057] After the ultrasonic parameters are generated, step S3 is performed. According to the ultrasonic parameters, the U-axis motion unit and the V-axis motion unit of the UVZ driving module are called to drive the bonding tool to vibrate at high frequency individually or together during bonding processing.

[0058] Since the ultrasonic vibration is performed separately by the U-axis motion unit and the V-axis motion unit with high-frequency reciprocating motion in this embodiment, when the U-axis motion unit moves alone, high-frequency vibration can be performed in the U-axis direction, that is, high-frequency vibration in the X-axis direction or the left-right direction. When the V-axis motion unit moves alone, high-frequency vibration can be performed in the V-axis direction, that is, high-frequency vibration in the Y-axis direction or the front-back direction. When the U-axis motion unit and the V-axis motion unit work at the same time, high-frequency vibration in other straight or curved directions other than the U-axis or V-axis directions can be performed. When the U-axis motion unit and the V-axis motion unit vibrate at the same high frequency and the same amplitude at the same time, ultrasonic vibration of a circular path is achieved by phase difference control. When the U-axis motion unit and the V-axis motion unit vibrate at the same high frequency and different amplitudes at the same time, ultrasonic vibration of any angle or any path including an elliptical path is formed by phase difference control. Due to the high frequency of movement, complex vector graphics can be formed in a very short time, such as arbitrary planar ultrasonic vector paths such as spiral lines, 8-shaped, and ∞-shaped, which greatly improves the richness of ultrasonic process applications, and the bonding quality and efficiency are also significantly improved. Thus, multi-directional, multi-angle, and multi-mode ultrasonic bonding can be achieved. At the same time, since the UVZ drive module is mainly used to drive the bonding tool to reciprocate between the solder joints to achieve wire bonding during the wire bonding process, the UVZ drive module can superimpose the ultrasonic vibration function in this process, which can make the energy transmission for driving the bonding process more comprehensive and concentrated. Compared with the existing technology with the same bonding strength, its bonding time is shorter, further improving the efficiency of the bonding process.

[0059] Since the ultrasonic vibration execution stage of the bonding process is performed on the solder joints, during the bonding process, the bonding tool moves alternately on the solder joints on the chip pad and the solder joints on the lead bracket. In order to adapt to the materials and characteristics of different working objects and different bonding needs, a second embodiment is further proposed on the basis of the first embodiment. The second embodiment mainly further illustrates the generation of ultrasonic parameters in step S2. In the second embodiment, the step of generating ultrasonic parameters in step S2 further includes:

[0060] Generate ultrasonic path for chip pad and generate ultrasonic path for lead standoff.

[0061] That is, when performing step S2, it is first necessary to distinguish whether to generate ultrasonic parameters for the chip pad or the lead support, and then execute different path strategies to formulate ultrasonic paths and generate ultrasonic paths;

[0062] When ultrasonic bonding the solder joints on the chip pads, based on the material properties of the chip pads, in particular, in order to solve the aluminum extrusion problem during the existing unidirectional ultrasonic vibration, to avoid the aluminum layer penetrating and damaging the underlying plating layer, and to avoid the aluminum layer being squeezed to the nearby PN line and causing a short circuit, the ultrasonic direction of the chip pad is generated to control the U-axis motion unit and the V-axis motion unit to work simultaneously to perform high-frequency vibration on a circular path, such as Figure 5 As shown, high-frequency vibration on a circular path can keep the aluminum layer uniformly within the circumference and near the edge. The aluminum material pushed by friction moves within the circumference, and the total amount of aluminum material within the vibration range remains constant. It does not diffuse outward or diffuses outward in a very small amount, thereby preventing the aluminum material from being pushed outward when subjected to a unidirectional force. It can prevent the aluminum material within the vibration range from being reduced and penetrating into the lower layer, and it can also prevent the aluminum material from moving in other directions and contacting the PN line, causing a chip short circuit.

[0063] When ultrasonic bonding is performed on the solder joints on the lead support, based on the characteristics of the lead support, which are different from the material characteristics of the chip pad, the main issue to be considered is how to effectively expand the solder joints according to the space around the solder joints to improve the effectiveness of bonding while maintaining symmetry and uniformity in appearance. In order to achieve the above purpose, the ultrasonic direction of generating the lead support described in this embodiment further includes:

[0064] Generate the line direction for bonding process;

[0065] Get the row direction of wire bonding at the solder joint;

[0066] An ultrasonic vibration path is generated perpendicular to the direction of the line.

[0067] Since the planar shape of the chip is generally a rectangle or a square, its solder joints are generally located at the four sides or the four corners. The solder joints on the four sides can perform unidirectional movement in the U-axis direction or the V-axis direction during bonding, that is, left-right vibration and front-back vibration. At the four corners, since the row direction is oblique, the ultrasonic vibration path perpendicular to the row direction is also oblique. At this time, the U-axis direction and the V-axis direction need to move simultaneously to achieve the execution of the oblique ultrasonic vibration path.

[0068] So, if Figure 6 As shown, when the line direction is parallel to the U-axis or V-axis direction, the U-axis motion unit and the V-axis motion unit are controlled to work in a decoupled manner to perform high-frequency vibration on a path perpendicular to the line direction;

[0069] When the line direction is inclined to the U-axis or V-axis direction, the U-axis motion unit and the V-axis motion unit are controlled to work simultaneously to perform high-frequency vibration on a path perpendicular to the line direction.

[0070] In order to realize the above motion control, the third embodiment provides a specific structural form of a UVZ driving module to realize the execution of the actions in the methods of the above embodiments. In the third embodiment, a UVZ driving module is set on the XY platform. The XY platform is composed of a linear driving mechanism in the X-axis and Y-axis directions. It can adopt an existing plane bearing driving structure or a gantry structure mounting driving structure. It will not be repeated here. The UVZ driving module, such as Figure 7-Figure 9 As shown, the UVZ driver module includes:

[0071] A mounting base 1, mounted on an XY platform of a bonding device;

[0072] The mounting base 1 is a basic structural component for mounting the wire bonding device in this embodiment, and is used to mount other components on the wire bonding device and to carry the entire wire bonding device to move on the XY platform of the bonding device during operation.

[0073] The U-axis driving assembly comprises a U-axis voice coil motor 2 and a U-axis main body 3. The U-axis voice coil motor 2 comprises a U-axis stator 21 and a U-axis mover 22. When installed, the U-axis stator 21 is horizontally installed in the mounting seat 1. The U-axis stator 21 is arranged on the mounting seat 1, and the U-axis mover 22 is connected to the U-axis main body 3. The U-axis mover 22 moves in the horizontal direction relative to the U-axis stator. The U-axis mover 22 is located in the U-axis stator 21 in a horizontal state. U-axis travel space is reserved on both sides of the U-axis stator 21 for the U-axis mover 22 to perform horizontal movement. The U-axis mover 22 performs U-axis horizontal reciprocating motion in the U-axis travel space.

[0074] A V-axis driving assembly comprises a V-axis voice coil motor 4 and a V-axis main body 5. The V-axis voice coil motor is vertically installed downward in the mounting seat 1. The V-axis voice coil motor 4 comprises a V-axis stator 41 and a V-axis mover 42. The V-axis stator 41 is vertically installed downward in the mounting seat 1. The V-axis stator 41 is arranged on the mounting seat 1, and the V-axis mover 42 is connected to the V-axis main body 5. When installed, the V-axis stator 41 is vertically installed on the first horizontal mounting surface of the mounting seat 1, and the V-axis mover 42 is located in a vertical state in the V-axis stator 41. V-axis travel space is reserved on both sides of the V-axis stator 41 for the V-axis mover 42 to perform horizontal movement. The V-axis mover 42 performs V-axis horizontal movement in the V-axis travel space.

[0075] The Z-axis driving assembly includes a Z-axis voice coil motor 6 and a Z-axis body 7 . The Z-axis voice coil motor includes a Z-axis stator 61 and a Z-axis mover 62 . The Z-axis stator 61 is disposed on the mounting seat 1 , and the Z-axis mover 62 is connected to the Z-axis body 7 .

[0076] During operation, the bonding device is installed on the Z-axis body 7, and the three-axis motion required for the bonding process is performed through the linkage of the U-axis drive assembly, the V-axis drive assembly and the Z-axis drive assembly. During bonding, the U-axis drive assembly and the V-axis drive assembly are linked to perform high-frequency reciprocating motion, and realize the high-frequency motion direction and trajectory described in the first embodiment above.

[0077] At the same time, if Figure 8 As shown, the U-axis stator 21 includes a U-axis stator magnet 211, and the U-axis mover 22 includes a U-axis mover coil 221. The U-axis mover coil 221 includes a first length segment 222, and the length of the first length segment 222 is greater than the coverage length of the U-axis stator magnet 211. When the U-axis and the V-axis are linked in parallel, the U-axis V-axis voice coil motor will drive the U-axis body to move in the V-axis direction when driving the V-axis movement, and then drive the U-axis mover to move in the V-axis direction. At this time, since the length of the U-axis mover coil 221 covered by the U-axis stator magnet 211 remains unchanged, the driving force of the U-axis voice coil motor 2 on the U-axis remains unchanged, thereby achieving electromagnetic decoupling. Since the movement influence of the U-axis and the V-axis is mutual, the requirement of mutual non-disturbance can be met by electromagnetic decoupling of one of the U-axis voice coil motor and the V-axis voice coil motor.

[0078] Similarly, if Figure 8As shown, in this embodiment, the Z-axis stator 61 is provided with a Z-axis stator magnet 611, and the Z-axis mover 62 is provided with a Z-axis mover coil 621, and the Z-axis mover coil 621 includes a second length segment 622, and the length of the second length segment 622 is greater than the coverage length of the Z-axis stator 611 magnet. The portion of the second length segment 622 that is greater than the coverage length of the Z-axis stator magnet 611 constitutes an electromagnetic decoupling stroke, which can avoid the influence of the movement in the V-axis direction on the driving force of the Z-axis mover. The specific principle is similar to that of the U-axis voice coil motor 2, and will not be repeated here.

[0079] The third embodiment solves the disturbance problem when the V-axis is linked to the U-axis or Z-axis in parallel by electromagnetic decoupling. When UV-axis linkage and VZ-axis linkage exist in the linkage scheme in the motion control of the three-axis motion unit, the mutual disturbance of the motion in the two vertical directions can be eliminated. However, in the three-axis motion unit, the three axes will affect each other when linked. The above electromagnetic decoupling scheme solves the disturbance problem when the V-axis is linked to the U-axis or Z-axis in parallel. In actual work, there are still situations where the U-axis and the Z-axis are linked, and the disturbance problem of the U-axis and the Z-axis in the case of UVZ three-way linkage. This embodiment solves this problem by mechanical decoupling the guide rail.

[0080] The setting of mechanical decoupling is based on the layout and mutual structural relationship of each component of the wire bonding device of this embodiment. Therefore, in order to clearly explain the principle of mechanical decoupling, the component morphology and structural relationship of this embodiment are first described in detail as a whole.

[0081] In this embodiment, Figure 7 and Fig. 9 As shown, the Z-axis body 7 is provided with a first guide rail 81 extending along the U-axis direction, and the Z-axis mover 62 of the Z-axis voice coil motor is provided with a first guide rail groove 82 extending along the U-axis direction, and the first guide rail 81 and the first guide rail groove 82 are slidably connected as a whole; when the Z-axis mover 62 moves vertically, the Z-axis body 7 makes reciprocating linear motion in the vertical direction, and when the U-axis mover drives the Z-axis body 7 to make linear motion in the horizontal U-axis direction, the horizontal U-axis motion driving force of the Z-axis body 7 is released by the first guide rail 81 and the first guide rail groove 82 and the Z-axis mover, that is, the driving force in the horizontal U-axis direction cannot be transmitted to the Z-axis mover, so the Z-axis mover is not affected by the driving force in the U-axis direction and maintains a standard Z-axis motion straight line, which can ensure both machining accuracy and device safety.

[0082] In this embodiment, a horizontal mounting plate 30 is provided above the Z-axis mover, and the horizontal mounting plate 30 is fixed on the mounting seat 1. The lower surface of the horizontal mounting plate 30 is provided with a second guide rail 91 extending along the V-axis, and the second guide rail 91 is connected to a second guide rail groove 92 extending along the V-axis direction, and the second guide rail 91 and the second guide rail groove 92 are slidably connected as a whole; when the Z-axis mover moves vertically, it drives the Z-axis body 7 to make reciprocating linear motion in the vertical direction, and when the V-axis mover drives the V-axis body to make linear motion in the horizontal V-axis direction, the second guide rail 91 and the second guide rail groove 92 can make the motion driving force in the horizontal V-axis direction be released by the V-axis decoupling guide rail and the Z-axis mover, that is, the driving force in the horizontal V-axis direction cannot be transmitted to the Z-axis mover, so the Z-axis mover is not affected by the driving force in the horizontal V-axis direction and maintains a standard Z-axis motion straight line.

[0083] In this embodiment, a transfer block 31 is fixed on the second guide groove 92, a third guide 101 extending along the Z-axis direction is provided on the Z-axis mover 62, a third guide groove 102 extending along the Z-axis direction is provided on the transfer block, and the third guide 101 and the third guide groove 102 are slidably connected as one. When the Z-axis mover drives the Z-axis body to make a linear motion in a direction perpendicular to the Z-axis direction, the driving force of the Z-axis mover 62 in the vertical direction on the moving parts on other axes is released by the third guide 101 and the third guide groove 102, that is, the driving force in the Z-axis direction is not transmitted to the U-axis and V-axis directions, so that the various moving parts on the U-axis and V-axis are not disturbed by the motion in the Z-axis direction.

[0084] It should be noted that the guide rails and guide rail grooves of each axis shown in the figure are simplified representations. In fact, during operation, the sliders and tracks of the decoupling guide rails of each axis can translate and slide relative to each other in the linear direction, but are inseparable in the vertical and sliding plane directions. That is, the guide rails and guide rail grooves of each axis can be matched by V-shaped sliders or tracks, or by setting ball bearings or slide grooves to achieve a structure that can translate but not separate. Only when the sliders and tracks of the decoupling guide rails in each direction are not separated from each other during operation can the structural stability of the overall wire bonding device be achieved.

[0085] In the mechanical structure of this embodiment, the motion units involved in the realization of ultrasonic bonding are mainly the U-axis motion unit and the V-axis motion unit and the decoupling structure or control related to the U-axis motion unit and the V-axis motion unit. The Z-axis motion unit is mainly used to drive and control the bonding tool for bonding processing and does not participate in ultrasonic vibration.

[0086] Therefore, in the above-mentioned embodiment, the UVZ three-axis motion unit of the wire bonding device is set, firstly, the horizontal drive of the UV-axis motion direction of the wire bonding device and the horizontal drive between the XY platform on the bonding device form a working mode that can operate independently and simultaneously and in a superimposed manner, and at the same time, the Z-axis motion direction of the wire bonding device is a linear motion. The Cartesian linear motion model is the most traditional and stable motion model, and has advantages in motion control. Many mature operation and control solutions can be used, so that the entire UVZ platform movement can achieve smoother and more precise operation and positioning.

[0087] like Fig.10 As shown, the fourth embodiment of the present application also provides a multi-directional ultrasonic bonding system, the system comprising:

[0088] A UVZ driving module 100, which includes at least a U-axis motion unit 110 and a V-axis motion unit 120 for high-frequency motion;

[0089] An ultrasound parameter generating module 200, used to generate ultrasound parameters;

[0090] The ultrasonic execution control module 300 controls the U-axis motion unit and the V-axis motion unit of the UVZ driving module to drive the bonding tool to vibrate at high frequency individually or together during bonding processing according to the ultrasonic parameters generated by the ultrasonic parameter generation module.

[0091] In this embodiment, in order to generate different ultrasonic parameters for the chip pad or the lead support, the ultrasonic parameter generation module 200 includes an ultrasonic direction generation unit 210 for the chip pad and an ultrasonic direction generation unit 220 for the lead support. Generate ultrasonic parameters for the chip pad or generate ultrasonic parameters for the lead support, then execute different path strategies to formulate ultrasonic paths and generate ultrasonic paths;

[0092] When ultrasonic bonding the solder joints on the chip pads, based on the material properties of the chip pads, in particular, in order to solve the aluminum extrusion problem during the existing unidirectional ultrasonic vibration, to avoid the aluminum layer penetrating and damaging the underlying plating layer, and to avoid the aluminum layer being squeezed to the nearby PN line and causing a short circuit, the ultrasonic direction of the chip pad is generated to control the U-axis motion unit and the V-axis motion unit to work simultaneously to perform high-frequency vibration on a circular path, such as Figure 5As shown, high-frequency vibration on a circular path can keep the aluminum layer uniformly within the circumference and near the edge. The aluminum material pushed by friction moves within the circumference, and the total amount of aluminum material within the vibration range remains constant. It does not diffuse outward or diffuses outward in a very small amount, thereby preventing the aluminum material from being pushed outward when subjected to a unidirectional force. It can prevent the aluminum material within the vibration range from being reduced and penetrating into the lower layer, and it can also prevent the aluminum material from moving in other directions and contacting the PN line, causing a chip short circuit.

[0093] Since the planar shape of the chip is generally a rectangle or a square, its solder joints are generally located at the four sides or the four corners. The solder joints on the four sides can perform unidirectional movement in the U-axis direction or the V-axis direction during bonding, that is, left-right vibration and front-back vibration. At the four corners, since the row direction is oblique, the ultrasonic vibration path perpendicular to the row direction is also oblique. At this time, the U-axis direction and the V-axis direction need to move simultaneously to achieve the execution of the oblique ultrasonic vibration path.

[0094] In this embodiment, ultrasonic vibration is realized by a U-axis motion unit and a V-axis motion unit, so the ultrasonic execution control module 3 includes a U-axis motion control unit 310 and a V-axis motion control unit 320. The U-axis motion control unit 310 and the V-axis motion control unit 320 control the U-axis motion unit 110 and the V-axis motion unit 120 to work separately or simultaneously to execute ultrasonic instructions.

[0095] The above description is only a preferred embodiment of the present application, and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. A multi-directional ultrasonic bonding method, characterized in that: The steps include: A UVZ driving module for driving a bonding tool is constructed based on an XY platform, wherein the UVZ driving module includes at least a U-axis motion unit and a V-axis motion unit for performing high-frequency motion; generating ultrasound parameters, wherein the ultrasound parameters include an ultrasound path; According to the ultrasonic parameters, during bonding processing, the U-axis motion unit and the V-axis motion unit of the UVZ drive module are called to drive the bonding tool to vibrate at high frequency individually or together; The U-axis motion unit comprises a U-axis voice coil motor and a U-axis body, wherein the U-axis voice coil motor comprises a U-axis stator and a U-axis mover, wherein the U-axis mover moves horizontally in the U-axis direction relative to the U-axis stator, the U-axis stator is arranged on a mounting seat, and the U-axis mover is connected to the U-axis body; The V-axis motion unit comprises a V-axis voice coil motor and a V-axis body, wherein the V-axis voice coil motor comprises a V-axis stator and a V-axis mover, wherein the V-axis mover moves horizontally in a V-axis direction relative to the V-axis stator, wherein the V-axis stator is disposed on a mounting seat, and the V-axis mover is connected to the V-axis body; The U-axis motion unit and the V-axis motion unit move individually or simultaneously by means of electromagnetic decoupling and / or mechanical decoupling.

2. The multi-directional ultrasonic bonding method according to claim 1, characterized in that: The UVZ driver module also includes: A Z-axis motion unit, comprising a Z-axis voice coil motor and a Z-axis body, wherein the Z-axis voice coil motor comprises a Z-axis stator and a Z-axis mover, wherein the Z-axis mover moves vertically in a Z-axis direction relative to the Z-axis stator, and the Z-axis mover is connected to the Z-axis body; The bonding tool is mounted on the Z-axis body.

3. The multi-directional ultrasonic bonding method according to any one of claims 1 or 2, characterized in that: The step of generating ultrasound parameters further comprises: Generate ultrasonic path for chip pad and generate ultrasonic path for lead holder.

4. The multi-directional ultrasonic bonding method according to claim 3, characterized in that: The ultrasonic direction of the chip pad is generated by controlling the U-axis motion unit and the V-axis motion unit to work simultaneously to perform high-frequency vibration on a circular path.

5. The multi-directional ultrasonic bonding method according to claim 4, characterized in that: The generating of the ultrasonic direction of the lead support further comprises: Generate the line direction for bonding process; Obtaining the line direction of the wire bonding at the solder joint, and generating an ultrasonic vibration path perpendicular to the line direction; When the line direction is parallel to the U-axis or V-axis direction, the U-axis motion unit and the V-axis motion unit are controlled to work in a decoupled manner to perform high-frequency vibration on a path perpendicular to the line direction; When the line direction is inclined to the U-axis or V-axis direction, the U-axis motion unit and the V-axis motion unit are controlled to work simultaneously to perform high-frequency vibration on a path perpendicular to the line direction.

6. A multi-directional ultrasonic bonding system, comprising: A UVZ driving module, wherein the UVZ driving module comprises at least a U-axis motion unit and a V-axis motion unit for performing high-frequency motion; A U-axis motion unit, comprising a U-axis voice coil motor and a U-axis body, wherein the U-axis voice coil motor comprises a U-axis stator and a U-axis mover, wherein the U-axis mover moves horizontally in a U-axis direction relative to the U-axis stator, the U-axis stator is disposed on a mounting seat, and the U-axis mover is connected to the U-axis body; A V-axis motion unit, comprising a V-axis voice coil motor and a V-axis body, wherein the V-axis voice coil motor comprises a V-axis stator and a V-axis mover, wherein the V-axis mover moves horizontally in a V-axis direction relative to the V-axis stator, wherein the V-axis stator is disposed on a mounting seat, and the V-axis mover is connected to the V-axis body; The U-axis motion unit and the V-axis motion unit move individually or simultaneously by means of electromagnetic decoupling and / or mechanical decoupling; An ultrasound parameter generation module, used for generating ultrasound parameters; The ultrasonic execution control module controls the U-axis motion unit and the V-axis motion unit of the UVZ driving module to drive the bonding tool to vibrate at high frequency individually or together during bonding processing according to the ultrasonic parameters generated by the ultrasonic parameter generation module.

7. The multi-directional ultrasonic bonding system according to claim 6, characterized in that: The ultrasonic parameter generation module includes an ultrasonic direction generation unit for a chip pad and an ultrasonic direction generation unit for a pin support.

8. The multi-directional ultrasonic bonding system according to claim 6, characterized in that: The ultrasonic execution control module includes a U-axis motion control unit and a V-axis motion control unit, and the U-axis motion control unit and the V-axis motion control unit control the U-axis motion unit and the V-axis motion unit to work separately or simultaneously to execute ultrasonic instructions.

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