Cutting knife for bonding wire system

Abstract

A cutting blade for a wire bonding system is provided herein. The cutting blade includes a body portion extending to a tip portion. The tip portion includes a first side and a second side, the first side defining a first face and a second face. The first face and the second face are not parallel to each other.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 461,352, filed on April 24, 2023, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to wire bonding (including ribbon bonding) operations and, more particularly, to cutting knives used in connection with such operations. Background Art

[0004] In the processing and packaging of semiconductor devices, wirebonding remains a widely used method of making electrical interconnections between two locations within a package (e.g., between a die pad of a semiconductor die and a lead of a leadframe). In connection with the formation of wire loops and / or ribbon loops in certain applications, a cutting knife may be used to cut into a conductive material (e.g., a round cross-section wire, a ribbon wire, etc.) to assist in severing the completed wire loop from a wire supply. U.S. Patent Nos. 4,976,392 and 8,141,765 (which relate to wirebonding systems) disclose the use of such cutting knives, and the entire contents of said U.S. Patent Nos. are incorporated herein by reference.

[0005] It would be desirable to provide improved methods of cutting wire on a wire bonding system, as well as improved cutting knives and associated wire bonding systems. Utility Model Content

[0006] According to an exemplary embodiment of the present invention, a wire bonding system is provided. The wire bonding system includes a bonding tool (e.g., a wire bonding tool, a wedge bonding tool also known as a wedge, etc.). The wire bonding system also includes a cutting knife disposed adjacent to the bonding tool. The cutting knife defines a face adjacent to the end of the cutting knife on one side of the cutting knife. The face is configured to contact the wire before the cutting operation.

[0007] According to other embodiments of the present invention, the wire bonding system described in the previous paragraph may have any one or more of the following features: after the wire bonding operation is completed, the cutting knife is configured to contact the welding tool before the cutting operation; after the wire bonding operation is completed, the cutting knife is configured to contact the welding tool during the cutting operation; the surface is configured to provide resistance to the cutting knife to prevent excessive cutting of the wire; the cutting knife defines another side, the other side faces the welding tool, the other side is opposite to the one side, the one side defines another side adjacent to the surface, the surface and the other side meet at the intersection area, and the surface and the other side are not parallel to each other; the cutting knife defines another side, the other side faces the welding tool, and the other side is opposite to the one side. One side is opposite, the one side defines another side adjacent to the side, the side is configured at a first angle relative to the vertical axis on the welding wire system, and the other side is configured at a second angle relative to the vertical axis of the welding wire system, the first angle is different from the second angle; the first angle is greater than the second angle; also includes a wire guide portion, the wire guide portion is configured to guide the wire toward a position below the welding tool, wherein after the wire arc is formed but before the cutting operation, the portion of the wire adjacent to the end of the cutting knife defines a third angle relative to the vertical axis of the welding wire system, and the first angle is greater than the third angle; also includes a monitoring system, the monitoring system is used to monitor the resistance characteristics (resistance) of the cutting knife when the cutting knife cuts into the wire on the welding wire system characteristic); further comprising a motion system configured to raise and lower the cutting knife so as to cut the wire on the wire bonding system; the resistance characteristic is related to an electrical characteristic of the motion system; the resistance characteristic is related to at least one of a current of the motion system, a speed of a portion of the motion system, and a position of a portion of the motion system; the motion system is configured to stop lowering the cutting knife when the resistance characteristic reaches a predetermined value; and / or the end comprises a stepped portion configured to limit penetration of the cutting knife into the wire during a cutting operation.

[0008] According to another exemplary embodiment of the present invention, a wire bonding system is provided. The wire bonding system includes a welding tool. The wire bonding system also includes a cutting knife disposed adjacent to the welding tool. The cutting knife defines a first side and a second side. The first side faces the welding tool. The second side is opposite to the first side. The second side defines a first flat portion adjacent to an end of the cutting knife and a second flat portion adjacent to the first flat portion. The first flat portion and the second flat portion meet at an intersection region. The first flat portion and the second flat portion are not parallel to each other. The intersection region is configured to contact the wire before a cutting operation.

[0009] According to other embodiments of the present invention, the wire welding system described in the previous paragraph may have any one or more of the following features: after the wire welding operation is completed, the cutting knife is configured to contact the welding tool before the cutting operation; after the wire welding operation is completed, the cutting knife is configured to contact the welding tool during the cutting operation; the first flat portion is configured to provide resistance to the cutting knife to prevent excessive cutting of the wire; the first flat portion is configured at a first angle relative to the vertical axis on the wire welding system, and the second flat portion is configured at a second angle relative to the vertical axis of the wire welding system, the first angle is different from the second angle; the first angle is greater than the second angle; and also includes a wire guide portion, the wire guide portion is configured to guide the wire toward a position below the welding tool, wherein, after the wire arc is formed but before the cutting operation, the wire guide portion is in contact with the cutting tool. The wire portion adjacent to the end of the cutting knife defines a third angle relative to the vertical axis of the wire bonding system, and the first angle is greater than the third angle; also includes a monitoring system, the monitoring system is used to monitor the resistance characteristics of the cutting knife when the cutting knife cuts into the wire on the wire bonding system; also includes a motion system, the motion system is configured to raise and lower the cutting knife so as to cut the wire on the wire bonding system; the resistance characteristic is related to the electrical characteristics of the motion system; the resistance characteristic is related to at least one of the current of the motion system, the speed of a part of the motion system, and the position of a part of the motion system; the motion system is configured to stop lowering the cutting knife when the resistance characteristic reaches a predetermined value; and / or the end includes a stepped portion, the stepped portion is configured to limit the penetration of the cutting knife into the wire during the cutting operation.

[0010] According to still another exemplary embodiment of the present invention, a wire welding system is provided. The wire welding system includes a welding tool. The wire welding system also includes a cutting knife disposed adjacent to the welding tool. The cutting knife defines a first side and a second side. The first side faces the welding tool. The second side is opposite to the first side. The second side defines a first flat portion adjacent to an end of the cutting knife and a second flat portion adjacent to the first flat portion. The first flat portion is configured at a first angle relative to a vertical axis on the wire welding system. The second flat portion is configured at a second angle relative to the vertical axis of the wire welding system. The first angle is different from the second angle. The first flat portion and the second flat portion meet at an intersection area, wherein the intersection area is configured to contact the wire before a cutting operation.

[0011] According to other embodiments of the present invention, the wire bonding system described in the previous paragraph may have any one or more of the following features: after the wire bonding operation is completed, the cutting knife is configured to contact the welding tool before the cutting operation; after the wire bonding operation is completed, the cutting knife is configured to contact the welding tool during the cutting operation; the first flat portion is configured to provide resistance to the cutting knife to prevent excessive cutting of the wire; the first angle is greater than the second angle; and further includes a monitoring system for monitoring the resistance characteristics of the cutting knife when the cutting knife cuts into the wire on the wire bonding system; and further includes a motion system, wherein the motion system is configured to raise and lower the cutting knife so as to cut the wire on the wire bonding system; the resistance characteristics and the motion The invention relates to an electrical characteristic of the motion system; the resistance characteristic is related to at least one of the current of the motion system, the speed of a part of the motion system, and the position of a part of the motion system; the motion system is configured to stop lowering the cutting knife when the resistance characteristic reaches a predetermined value; the end includes a stepped portion, which is configured to limit the penetration of the cutting knife into the wire during the cutting operation; and / or also includes a wire guide portion, which is configured to guide the wire toward a position below the welding tool, wherein, after the wire arc is formed but before the cutting operation, the wire portion adjacent to the end of the cutting knife defines a third angle relative to the vertical axis of the wire welding system, and the first angle is greater than the third angle.

[0012] According to yet another exemplary embodiment of the present invention, a method for cutting a wire in connection with a wire bonding system is provided. The method comprises the following steps: (a) providing a bonding tool; (b) providing a cutting knife adjacent to the bonding tool; (c) moving the cutting knife to contact a portion of the wire; and (d) cutting another portion of the wire away from the portion of the wire.

[0013] According to other embodiments of the present invention, the method described in the previous paragraph may have any one or more of the following features: step (c) includes bringing the welding tool into contact with the cutting knife before step (d); step (c) includes bringing the welding tool into contact with the cutting knife during step (d); it also includes a step, namely, step (e) - providing a monitoring system to monitor the resistance characteristics of the cutting knife during step (d); and / or it also includes a step, namely, terminating step (d) when the resistance characteristics reach a predetermined value.

[0014] According to yet another exemplary embodiment of the present invention, a cutting blade for a wire bonding system is provided, the cutting blade comprising: a body portion extending to an end portion, the end portion comprising a first side and a second side, the first side defining a first face and a second face, the first face and the second face being non-parallel to each other.

[0015] According to other embodiments of the present invention, the cutting knife described in the previous paragraph may have any one or more of the following features: at least one of the first surface and the second surface is configured to provide resistance to the cutting knife to prevent excessive cutting of the wire; the first surface is adjacent to the end of the end portion, and the first surface is configured to provide resistance to the cutting knife to prevent excessive cutting of the wire; the first surface is adjacent to the end of the end portion, wherein the first surface is configured at a first angle relative to the vertical axis, and the second surface is configured at a second angle relative to the vertical axis, and the first angle is different from the second angle; the first angle is greater than the second angle; the cutting knife is configured to contact the wire portion adjacent to the end of the cutting knife after the line arc is formed but before the cutting operation, and the line arc defines a third angle relative to the vertical axis, and the first angle is greater than the third angle; the end portion includes a stepped portion, and the stepped portion is configured to limit the penetration of the cutting knife into the wire during the cutting operation; and / or the stepped portion defines a step width so that a control signal of a monitoring system used in conjunction with the cutting knife can be monitored.

[0016] According to yet another exemplary embodiment of the present invention, another cutting blade for a wire bonding system is provided. The cutting blade includes: a body portion extending to an end portion, the end portion including a first side and a second side, the first side defining a first face and a second face, the first face and the second face defining an intersection, the intersection being configured to contact a wire during a cutting operation.

[0017] According to other embodiments of the present invention, the cutting knife described in the previous paragraph may have any one or more of the following features: at least one of the first surface and the second surface is configured to provide resistance to the cutting knife to prevent excessive cutting of the wire; the first surface is adjacent to the end of the end portion, and the first surface is configured to provide resistance to the cutting knife to prevent excessive cutting of the wire; the first surface is adjacent to the end of the end portion, wherein the first surface is configured at a first angle relative to the vertical axis, and the second surface is configured at a second angle relative to the vertical axis, and the first angle is different from the second angle; the first angle is greater than the second angle; the cutting knife is configured to adjust the wire portion adjacent to the end of the cutting knife after the line arc is formed but before the cutting operation, and the line arc defines a third angle relative to the vertical axis, and the first angle is greater than the third angle; the end portion includes a stepped portion, and the stepped portion is configured to limit the penetration of the cutting knife into the wire during the cutting operation; and / or the stepped portion defines a step width so that a control signal of a monitoring system used in conjunction with the cutting knife can be monitored.

[0018] According to yet another exemplary embodiment of the present invention, yet another cutting blade for a wire welding system is provided. The cutting blade includes: a body portion extending to an end portion, the end portion including a first side and a second side, the first side defining a first face and a second face, the first face being disposed at a first angle relative to a vertical axis, and the second face being disposed at a second angle relative to the vertical axis, the second angle being different from the first angle.

[0019] According to other embodiments of the present invention, the cutting knife described in the previous paragraph may have any one or more of the following features: at least one of the first surface and the second surface is configured to provide resistance to the cutting knife to prevent excessive cutting of the wire; the first surface is adjacent to the end of the end portion, and the first surface is configured to provide resistance to the cutting knife to prevent excessive cutting of the wire; the first surface is adjacent to the end of the end portion, wherein the first angle is greater than the second angle; the cutting knife is configured to adjust the wire portion adjacent to the end of the cutting knife after the wire arc is formed but before the cutting operation, the wire arc defines a third angle relative to the vertical axis, and the first angle is greater than the third angle; the end portion includes a stepped portion, the stepped portion is configured to limit the penetration of the cutting knife into the wire during the cutting operation; and / or the stepped portion defines a step width so that a control signal of a monitoring system used in conjunction with the cutting knife can be monitored.

[0020] According to yet another exemplary embodiment of the present invention, yet another cutting knife for a wire bonding system is provided. The cutting knife includes: a body portion extending to an end portion, the end portion including a first side and a second side, the first side defining a first face and a second face, the end portion also including a stepped portion, the stepped portion being configured to limit penetration of the cutting knife into the wire during a cutting operation.

[0021] According to other embodiments of the present invention, the cutting knife described in the previous paragraph may have any one or more of the following features: at least one of the first surface and the second surface is configured to provide resistance to the cutting knife to prevent excessive cutting of the wire; the first surface is adjacent to the end of the end portion, and the first surface is configured to provide resistance to the cutting knife to prevent excessive cutting of the wire; the first surface is configured at a first angle relative to the vertical axis, and the second surface is configured at a second angle relative to the vertical axis, and the first angle is different from the second angle; the first surface is adjacent to the end of the end portion, wherein the first angle is greater than the second angle; the cutting knife is configured to contact the wire portion adjacent to the end of the cutting knife after the wire arc is formed but before the cutting operation, and the wire arc defines a third angle relative to the vertical axis, and the first angle is greater than the third angle; the stepped portion defines a step width so that a control signal of a monitoring system used in conjunction with the cutting knife can be monitored; and / or the stepped portion defines a step height so that the end of the cutting knife can cut to a predefined percentage of the wire diameter. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will be best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not drawn to scale. Instead, the dimensions of the various features are arbitrarily expanded or reduced for clarity. The drawings include the following figures:

[0023] Figure 1 is a block diagram side view illustrating a wire bonding system for bonding wire (e.g., round wire, ribbon wire, etc.) according to an exemplary embodiment of the present invention;

[0024] Figures 2A-2D is a cross-sectional side view of components of a wire bonding system illustrating a cutting operation according to an exemplary embodiment of the present invention;

[0025] Figures 3A-3G is a cross-sectional side view and block diagrammatic view of components of a wire bonding system illustrating a cutting operation according to one or more exemplary embodiments of the present invention;

[0026] Figures 4A-4D is a cross-sectional side view and block diagrammatic view of components of another wire bonding system illustrating a cutting operation according to an exemplary embodiment of the present invention;

[0027] Figure 5 is a cross-sectional side view and block diagrammatic illustration of components of yet another wire bonding system according to an exemplary embodiment of the present invention;

[0028] Figure 6 is a cross-sectional side view and block diagrammatic illustration of elements of yet another wire bonding system according to an exemplary embodiment of the present invention; and

[0029] Figure 7 is a flow chart illustrating a method of cutting a wire in association with a wire bonding system according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION

[0030] The terms "wire," "ribbon," and "conductive material" are used herein to generically describe materials that are welded by a wire bonding system (e.g., a wedge bonding system). It is understood that a wire bonding system can weld either wire or ribbon, as desired in a given application. Thus, it is understood that these terms can be used interchangeably and are not intended to limit one another. For example, as used herein, the term "wire" is intended to refer to round wire (i.e., wire having a circular cross-section), ribbon wire, and the like.

[0031] Wirebonds are widely used as a reliable and cost-effective interconnect method in semiconductor packaging. In wedge bonding (including ribbon bonding), a cutter is sometimes used to cut the wire after the last weld is completed. There are generally two ways to cut the wire in various wire bonding processes: rear-cut applications and front-cut applications. For front-cut applications, the cutter and wire guide are installed on different sides of the welding tool; for rear-cut applications, the cutter and wire guide are on the same side. A predetermined cutting depth can be defined before the welding operation so that the welding process can continue with the desired operation. For front-cut applications, the cutting depth can be predetermined to be ≥100% of the wire diameter. Rear-cut applications require a more precise cutting process.

[0032] In order to have a stable and controlled cutting process, the cutting knife (e.g., cutting knife 112) can be as expected very close to (and possibly even in contact with) the welding tool when the cutting knife moves down and cuts into the wire (e.g., wire 116) at the desired cutting point. Due to process variations, the cutting knife may not always contact the welding tool. In addition, the cutting knife may sometimes cut into the wire at an undesirable point, resulting in unstable cutting depth and tail length. When the cutting depth is less than a predetermined threshold (e.g., <65% of the wire diameter or "shallow limit"), the wire cannot be terminated and the welding process stops. When the cutting depth is greater than another predetermined threshold (e.g., >85% of the wire diameter or "deep limit"), the wire cannot be fed under the welding tool and the welding process also stops. In some embodiments, a "cutting window" can be defined as the value difference between the maximum value of the cutting depth adjustment (e.g., a parameter that defines the cutting depth of the cutting knife) and the minimum value of the cutting depth adjustment. A small cutting window makes the cutting process unstable and challenging. A larger cutting window is generally desired.

[0033] Certain embodiments illustrated and described herein provide unique tip geometry designs to ensure a large cutting window and consistent cutting position. Such embodiments can produce consistent wire tail length and / or consistent cutting depth, so that a stable cutting process can be achieved. The wire exiting the wire guide has an angle relative to the vertical axis of the wire bonding machine. (e.g., ~40°, 20° to 60°, etc.) (e.g., see Figure 3B ). To prevent the tip of the cutting knife from cutting into the wire before it reaches the desired cutting point, the surface near the tip of the cutting knife may have an angle greater than that of the wire. Large angles α (e.g., ~60°, 40° to 80°, etc.) (e.g., see Figure 3B ). The optimal angle α and width of the "face" ensure that the cutter slides along the wire at the face and / or intersection (e.g., "corner") of the cutter before the end reaches the cutting position (e.g., cutting position 136). Although there are many variations in the process (e.g., settings, vibrations, etc.), the end of the cutter cuts into the wire at the optimal cutting position (e.g., cutting position 136) as expected, resulting in a consistent cutting depth and tail length. In addition, the design of the face adds more resistance to the cutter and prevents over-cutting (i.e., cutting beyond the deep limit) when the end approaches the deep limit, resulting in a larger (e.g., >2×) cutting window. The optimal width of the face can also eliminate undesirable marks at the wire, which can be displayed at the first weld of the next wire in the next welding operation.

[0034] In certain embodiments, the cutting knife includes a step (e.g., a stepped portion), as in U.S. Pat. No. 8,141,765. The step height (e.g., step height 140) can be designed as a percentage of the wire diameter so that the cutting knife end can cut to a predefined percentage (e.g., 75%) of the wire diameter, or within a desired cutting depth range (e.g., 65% to 85% of the wire diameter). The step width (e.g., step width 142) has multiple functions, including physically preventing the cutting knife from going deeper into the wire, and generating a motion control signal to stop the drive to the cutting motion. Before the step width contacts the wire, the end of the cutting knife can smoothly cut into the wire, and the resistance to further cutting can be detected (e.g., using a monitoring system). When the step contacts the wire, the step width quickly generates an increased resistance that prevents the end from going deeper. However, for some motion control systems, the driving force that moves the cutting knife downward can be much greater than the resistance generated by the stepped width. Therefore, the step width may not effectively stop the cutting. For such a motion control system, the control signal may be used desirably to stop the driving force so that the cutting knife will stop moving.

[0035] Various types of control signals may be monitored. For example, motor current may be monitored (e.g., current of a motion system for raising and lowering a cutting blade) to monitor resistance characteristics (e.g., resistance characteristics of a cutting blade when the cutting blade cuts into a wire on a wire bonding system). Such control signals may be monitored for various cutting blades within the scope of the present invention (not just cutting blades with steps). If resistance suddenly increases (e.g., due to the step width contacting the wire, due to the intersection contacting the wire, due to the face of the cutting blade contacting the wire, etc.), the driving force (e.g., the lowering of the cutting blade) may be set to zero and the cutting process stopped.

[0036] According to certain aspects of the present invention, the step width can be optimized. In order to generate a strong signal, a large step width is desirable. However, a step width that is too wide pushes the cutting blade tip away from the edge of the welding tool, reducing the efficiency of the cutting process. A small step width (e.g., step width 142) allows an efficient cutting process, but the control signal may be too small to accurately stop the cutting process.

[0037] Referring now to the accompanying drawings, Figure 1 1. The wire bonding system 100 is illustrated. The wire bonding system 100 is illustrated as defining a vertical axis 104. The wire bonding system 100 includes a bonding head assembly 102. The bonding head assembly 102 is illustrated as supporting (or including) a bonding tool 110 (e.g., a wire bonding tool, a wedge bonding tool also known as a wedge splitter, etc.), a cutting blade 112 (disposed near the bonding tool 100), and a wire guide 114. The wire bonding system 100 also includes a support structure 120 for supporting a workpiece (e.g., a substrate, a semiconductor element, a die, a chip, etc.). The wire bonding system 100 also includes a motion system 106 and a monitoring system 108. The motion system 106 is configured to raise and lower the cutting blade 112 so as to cut the wire on the wire bonding system 100. The monitoring system 108 (e.g., including a computer, a processor, etc.) monitors the resistance characteristics of the cutting blade 112 (e.g., when the cutting blade 112 cuts into the wire on the wire bonding system 100). Examples of such a resistance characteristic may be: an electrical characteristic of the motion system 106 (e.g., a current associated with the motion system 106); a speed of a portion of the motion system (e.g., a portion of the motion system that may include and / or carry the cutting blade 112); a position of a portion of the motion system (e.g., a portion of the motion system that may include and / or carry the cutting blade 112), etc. The monitoring system 108 may be configured to stop lowering the cutting blade 112 when the resistance characteristic reaches a predetermined value.

[0038] exist Figures 2A-2D , Figures 3A-3G , Figures 4A-4D , Figure 5 and Figure 6In each of the examples, details of exemplary elements of a wire bonding system according to an exemplary embodiment of the present invention are shown. Figures 2A-2D , Figures 3A-3G , Figures 4A-4D , Figure 5 and Figure 6 ) can be in Figure 1 A portion of a more general wire bonding system 100 is shown in FIG.

[0039] Reference now Figures 2A-2D , the lower portion of each of the welding tool 110, the cutting blade 112, and the wire guide 114 is illustrated. Figures 2A-2D In the process, a line arc is formed and the cutting operation is completed. Figure 2A , support structure 120 is illustrated as supporting base plate 118. Welding tool 110 is illustrated as having formed weld 116a (e.g., first weld) from wire 116 at a welding position (e.g., first welding position). Wire 116 is provided by wire guide 114 (e.g., before, during, and / or after forming weld 116a).

[0040] Reference now Figure 2B , a length of wire has been extended from the welding portion 116a to form a wire arc 116b including a second welding portion 116c. After the second welding portion 116c is formed, the cutting operation can be completed. Now refer to Figure 2C , the cutting blade 112 is shown as being lowered (e.g., by the motion system 106) in relation to the cutting operation. Prior to the cutting operation, a portion (e.g., a face, an intersection, etc.) of the cutting blade 112 may contact a portion (e.g., a portion that will not be cut) of the wire 116 (e.g., see Figure 3C and Figure 3D ). In addition, before the cutting operation, the cutting blade 112 may contact the welding tool 110 (see, for example, Figure 3E ).exist Figure 2C , the cutting blade 112 is illustrated as cutting into the wire 116 (e.g., penetrating the wire, etc.). The cutting blade 112 may continue to cut into the wire 116 until a certain threshold is reached (e.g., when a resistance threshold is reached, when a depth threshold is reached, when 65%-85% of the wire diameter is cut, when 75% of the wire diameter is cut, etc.).

[0041] Reference now Figure 2D After the cutting operation, the welding head assembly 102 (not in Figures 2A-2D , but see Figure 1 ) has been moved laterally (e.g., to the right along the x-axis) and vertically (e.g., upward along the z-axis) such that welding tool 110, cutting blade 112, and wire guide 114 are shown away from wire arc 116b. Figure 2D As shown in FIG. 1 , wire tail 116d is shown beneath bonding tool 110 for use in connection with the formation of the next wire arc.

[0042] Reference now Figures 3A-3G , the cutting blade 112 is shown in more detail, before the cutting operation (i.e. Figure 3A-3B ) and during the cutting operation (i.e. Figure 3C-3G ).although Figures 3A-3G The images are provided as a series that appear sequentially in time, but it should be understood that certain images may be included (or excluded) from different exemplary embodiments of the invention.

[0043] The cutting blade 112 is shown as including a body portion 113 extending to (e.g., terminating at) an end portion 115. A first side 122 (facing the welding tool 110) and a second side 124 (opposite to the first side 122) are shown as being disposed on either side of the body portion 113 and / or the end portion 115. The second side 124 includes a first flat portion 126 and a second flat portion 128. The first flat portion 126 (or face) may be configured to contact the wire 116 (e.g., see FIG. 1 ) prior to the cutting operation. Figure 3D ). The first flat portion 126 (e.g., a face) and the second flat portion 128 (e.g., a face) define an intersection region 130 (e.g., a point, an edge, an intersection edge, a protruding region, etc.). The intersection region 130 can be configured to contact the wire prior to a cutting operation (e.g., see Figure 3C ). The first side 122 and the second side 124 (particularly the first flat portion 126) define a tip 132 (e.g., a point, a cutting edge, etc.). The tip 132 can be used to cut into the wire 116 at a desired cutting location 136 adjacent to the edge 134 of the welding tool 110. The first flat portion 126 is illustrated as being configured at a first angle α relative to the vertical axis 104 (of the welding wire system 100). The second flat portion 128 is illustrated as being configured at a second angle β relative to the vertical axis 104. As shown, the first angle α is different from the second angle β; specifically, in the illustrated embodiment, the first angle α is greater than the second angle β. The wire 116 is disposed at a third angle relative to the vertical axis 104. (e.g., 20° to 60°, ~40°, etc.) is provided (e.g., see Figure 3B ). More specifically, after the wire arc is formed but before the cutting operation, the portion of the wire adjacent the end of the cutting blade defines an angle relative to the vertical axis of the wire bonding system. The wire angle can be smaller than the first angle α. In addition, the second angle β can be smaller than the third angle

[0044] Describe in order, Figure 3A-3BThe figure shows the process of forming the second welding portion 116c (see Figure 2B ) followed by the cutting knife 112. Figure 3C-3G The figure shows the lowering of the cutting knife 112 and the cutting operation of the wire 116. Figure 3C The diagram shows a cutting operation (where the cutting operation is performed in Figure 3F-3G ) before the intersection region 130 contacts the wire 116. Figure 3D When the cutting blade 112 is further lowered, the first flat portion 126 (eg, the surface) is in the cutting operation (wherein the cutting operation is Figure 3F-3G When the cutting blade 112 approaches the "deep limit" (e.g., >85% of the wire diameter), the first flat portion 126 can provide a higher resistance to the cutting blade 112 to prevent over-cutting of the wire 116. Figure 3E When the cutting blade 112 is further lowered as shown in FIG. , the cutting blade 112 may contact the welding tool 110 before (and / or during, and / or after) the cutting operation. Figure 3F-3G Illustration of a cutting operation (similar to Figure 2C The cutting operation shown in ).

[0045] As given above, the cutting blade according to aspects of the present invention may include a "stepped" portion. Figures 4A-4D , the cutting blade 112a is shown, before the cutting operation (i.e. Figure 4A-4B ) and during the cutting operation (i.e. Figure 4C-4D ). Cutter 112a is similar to cleaver 112 (with the above description of Figures 2A-2D and Figures 3A-3G 130 degrees. The stepped portion 138 is illustrated as defining a 90 degree angle; however, it should be understood that the stepped portion 138 may define any angle between 0 and 180 degrees. Some exemplary ranges include: 80 to 100 degrees; 70 to 110 degrees; 60 to 120 degrees; and 50 to 130 degrees. It should be understood that the angle defined by the stepped portion may include a curved, rounded, and / or chamfered shape, whereby the angle may be understood to be defined by one or more tangents to the curved, rounded, and / or chamfered shape (e.g., at or near the termination points of such curved, rounded, and / or chamfered shape).

[0046] The cutting blade 112a is illustrated as including a body portion 113a (eg, see FIG. 1 ) extending to (eg, terminating at) an end portion 115a. Figure 4C). The first side 122a (facing the welding tool 110) and the second side 124a (opposite to the first side 122a) are illustrated as being disposed on either side of the body portion 113a and / or the end portion 115a. The second side 124a includes a first flat portion 126a and a second flat portion 128a. The first flat portion 126a (or face) may be configured to contact the wire 116 prior to a cutting operation. The first flat portion 126a (e.g., face) and the second flat portion 128a (e.g., face) define an intersection area 130a (e.g., edge, intersection edge, protruding area, etc.). The first side 122a and the second side 124a (particularly the first flat portion 126a) define an end 132a (e.g., point, cutting edge, etc.). The end 132a may be used to cut into the wire 116 at a desired cutting location 136 adjacent to the edge 134 of the welding tool 110. The first flat portion 126a is shown as being at a first angle α relative to the vertical axis 104 (of the wire bonding system 100). a The second flat portion 128a is shown as being at a second angle β relative to the vertical axis 104. a Configuration. As shown, the first angle α a With the second angle β a Different; specifically, the first angle α a The second angle β a The stepped portion 138 includes a step height 140 and a step width 142. The step height 140 can be designed to be a predetermined percentage (e.g., 75%) of the wire diameter so that the cutting knife 112a can cut up to a predetermined percentage (e.g., 75%) of the wire diameter. The predetermined percentage can be within a desired cutting depth range (e.g., 65% to 85% of the wire diameter). The step width 142 has multiple functions, including physically preventing the cutting knife 112a from going deeper into the wire 116, and generating a motion control signal to stop driving the cutting motion (e.g., using a motor).

[0047] Figures 2A-2D , Figures 3A-3G and Figures 4A-4D A "cut-after" condition is illustrated (ie, where the conductive material is cut on the weld side proximate to the wire guide 114). The present invention is not therefore limited to "cut-after" applications. Figure 5 and Figure 6 The cutting blade 112 and the cutting blade 112a are respectively illustrated in a "pre-cutting" application. Specifically, the cutting blade 112 and the cutting blade 112a are illustrated as being before the cutting operation.

[0048] Figure 7is a flow chart according to certain exemplary embodiments of the present invention. As will be appreciated by those skilled in the art, certain steps included in the flow chart may be omitted; certain additional steps may be added; and the order of the steps may be altered from the order shown. Dashed lines may be considered "optional" in certain embodiments.

[0049] Figure 7 7 is a flow chart illustrating a method of cutting a wire in connection with a wire bonding system. At step 700, a bonding tool (e.g., bonding tool 110) is provided. At step 702, a cutting blade (e.g., cutting blade 112, cutting blade 112a, etc.) is provided adjacent to the bonding tool. At step 704, the cutting blade is moved to contact a portion of the wire (e.g., wire 116) (e.g., see FIG. 7 ). Figure 3C The intersection region 130 contacts the wire 116, and Figure 3D In step 706, another portion of the wire is cut away from a portion of the wire using a cutting knife (e.g., see Figure 3E The wire 116 is Figure 3C and Figure 3D At optional step 708, a monitoring system is provided to monitor the resistance characteristic of the cutting blade during step 706. At optional step 710, the cutting (of step 706) is terminated after the resistance characteristic reaches a predetermined value (e.g., the current reading of the motor exceeds a predefined threshold, the signal corresponding to the frictional resistance or mechanical resistance of the cutting blade exceeds a predefined threshold, etc.).

[0050] By various embodiments of the present invention, a well-controlled cutting process (e.g., producing an accurate cutting depth and a consistent tail length) is provided. Certain cutting knives of the present invention and associated control systems make the cutting process stable and consistent. In addition, the cutting position can be maintained at an optimal position, producing a consistent tail length and cutting depth. Control of the cutting depth prevents undercutting (e.g., where the wire is not terminated and the welding process stops) or overcutting (e.g., where no wire is fed to the welding tool). In addition, certain embodiments of the present invention can provide advantages such as a wider cutting window, a more accurate cutting depth, a more consistent tail length, a higher throughput, and a higher yield.

[0051] Although the invention has been illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and equivalents of the claims and without departing from the invention.

Claims

1. A cutting knife for a wire welding system, characterized in that include: a body portion extending to a terminal portion, the terminal portion including a first side and a second side, the first side defining a first face and a second face, The first surface and the second surface are not parallel to each other.

2. The cutting knife according to claim 1, wherein: At least one of the first surface and the second surface is configured to provide resistance to the cutting knife to prevent over-cutting of the wire.

3. The cutting knife according to claim 1, wherein: The first surface is adjacent to the end of the end portion, and the first surface is configured to provide resistance to the cutting knife to prevent over-cutting of the wire.

4. The cutting knife according to claim 1, wherein: The first face is adjacent to a terminal end of the terminal portion, wherein the first face is disposed at a first angle relative to a vertical axis, and the second face is disposed at a second angle relative to the vertical axis, the first angle being different from the second angle.

5. The cutting knife according to claim 4, wherein: The first angle is greater than the second angle.

6. The cutting knife according to claim 4, wherein: The cutting blade is configured to contact a portion of the wire adjacent a distal end of the cutting blade after formation of a wire arc but prior to a cutting operation, the wire arc defining a third angle relative to a vertical axis, the first angle being greater than the third angle.

7. The cutting knife according to claim 1, wherein: The end portion includes a stepped portion configured to limit penetration of the cutting blade into the wire during a cutting operation.

8. The cutting knife according to claim 7, wherein: The stepped portion defines a step width such that a control signal of a monitoring system used in connection with the cutting knife can be monitored.

9. A cutting knife for a wire welding system, characterized in that include: A body portion extends to a tip portion, the tip portion including a first side and a second side, the first side defining a first face and a second face, the first face and the second face defining an intersection point configured to contact a wire during a cutting operation.

10. The cutting knife according to claim 9, wherein: At least one of the first surface and the second surface is configured to provide resistance to the cutting blade to prevent over-cutting of the wire.

11. The cutting knife according to claim 9, wherein: The first surface is adjacent to a terminal end of the terminal portion, and the first surface is configured to provide resistance to the cutting blade to prevent over-cutting of the wire.

12. The cutting knife according to claim 9, wherein: The first face is adjacent to a terminal end of the terminal portion, wherein the first face is disposed at a first angle relative to a vertical axis, and the second face is disposed at a second angle relative to the vertical axis, the first angle being different from the second angle.

13. The cutting knife according to claim 12, wherein: The first angle is greater than the second angle.

14. The cutting knife according to claim 12, wherein: The cutting blade is configured to adjust a portion of the wire adjacent a distal end of the cutting blade after a wire arc is formed but prior to a cutting operation, the wire arc defining a third angle relative to a vertical axis, the first angle being greater than the third angle.

15. The cutting knife according to claim 9, wherein: The end portion includes a stepped portion configured to limit penetration of the cutting blade into the wire during a cutting operation.

16. The cutting knife according to claim 15, wherein: The stepped portion defines a step width such that a control signal of a monitoring system used in connection with the cutting knife can be monitored.

17. A cutting knife for a wire bonding system, characterized in that include: A body portion extending to an end portion, the end portion including a first side and a second side, the first side defining a first face and a second face, the first face being disposed at a first angle relative to a vertical axis, and the second face being disposed at a second angle relative to the vertical axis, the second angle being different from the first angle.

18. The cutting knife according to claim 17, wherein: At least one of the first surface and the second surface is configured to provide resistance to the cutting blade to prevent over-cutting of the wire.

19. The cutting knife according to claim 17, wherein: The first surface is adjacent to a terminal end of the terminal portion, and the first surface is configured to provide resistance to the cutting blade to prevent over-cutting of the wire.

20. The cutting knife according to claim 17, wherein: The first face is adjacent to an end of the end portion, wherein the first angle is greater than the second angle.

21. The cutting knife according to claim 20, wherein: The cutting blade is configured to adjust a portion of the wire adjacent a distal end of the cutting blade after a wire arc is formed but prior to a cutting operation, the wire arc defining a third angle relative to a vertical axis, the first angle being greater than the third angle.

22. The cutting knife according to claim 17, wherein: The end portion includes a stepped portion configured to limit penetration of the cutting blade into the wire during a cutting operation.

23. The cutting knife according to claim 22, wherein: The stepped portion defines a step width such that a control signal of a monitoring system used in connection with the cutting knife can be monitored.

24. A cutting knife for a wire welding system, characterized in that include: a body portion extending to a terminal portion, the terminal portion including a first side and a second side, the first side defining a first face and a second face, The end portion also includes a stepped portion configured to limit penetration of the cutting blade into the wire during a cutting operation.

25. The cutting knife according to claim 24, wherein At least one of the first surface and the second surface is configured to provide resistance to the cutting blade to prevent over-cutting of the wire.

26. The cutting knife according to claim 24, wherein The first surface is adjacent to a terminal end of the terminal portion, and the first surface is configured to provide resistance to the cutting blade to prevent over-cutting of the wire.

27. The cutting knife according to claim 24, wherein: The first surface is disposed at a first angle relative to a vertical axis, and the second surface is disposed at a second angle relative to the vertical axis, wherein the first angle is different from the second angle.

28. The cutting knife according to claim 27, wherein The first face is adjacent to an end of the end portion, wherein the first angle is greater than the second angle.

29. The cutting knife according to claim 28, wherein The cutting blade is configured to contact a portion of the wire adjacent a distal end of the cutting blade after a wire arc is formed but prior to a cutting operation, the wire arc defining a third angle relative to a vertical axis, the first angle being greater than the third angle.

30. The cutting knife according to claim 24, wherein: The stepped portion defines a step width such that a control signal of a monitoring system used in connection with the cutting knife can be monitored.

31. The cutting knife according to claim 24, wherein: The stepped portion defines a step height such that the cutting knife tip can cut to a predefined percentage of the wire diameter.

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