Method for detecting welding between welding wire and welding position on wire bonding machine

Abstract

A method for determining a welding condition between a wire and at least one welding position of a workpiece is provided. The method comprises the following steps: (a) using a welding tool of a wire bonding machine to weld a portion of the wire to a welding position of the workpiece; (b) determining a motion curve of the welding tool for determining whether the portion of the wire is welded to the welding position, the motion curve being configured to cause the wire to break during the motion curve if the portion of the wire is not welded to the welding position; and (c) moving the welding tool along the motion curve to determine whether the portion of the wire is welded to the welding position. Other methods for determining a welding condition between a wire and at least one welding position of a workpiece are also provided.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 62 / 857,027, filed on June 4, 2019, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the formation of wire loops and other wire bond structures, and more particularly to improved methods of detecting the condition of a welded portion of a wire. Background Art

[0004] In the process and packaging of semiconductor devices, wire bonding (e.g., ball bonding, wedge bonding, etc.) continues to be a widely used method for providing electrical interconnection between locations within a package (such as between a die pad of a semiconductor die and a lead of a lead frame). More specifically, using a wire bonder (also known as a wire bonder), a wire arc is formed between corresponding locations to be electrically interconnected.

[0005] An exemplary conventional wire bonding sequence for a simple wire arc (using ball bonding techniques) includes: (1) forming a free air ball on the end of the wire extending from the bonding tool; (2) using the free air ball to form a first bond of the wire arc on the die pad of the semiconductor die; (3) extending a length of wire in a desired shape between the die pad and the lead of the lead frame; (4) stitch bonding the wire to the lead of the lead frame to form a second bond of the wire arc; and (5) severing the supply wire from the newly formed wire arc. When forming a bond between (a) the end of the wire arc and (b) the bonding site (e.g., die pad, lead, etc.), various types of bonding energy may be used, including, for example, ultrasonic energy, thermosonic energy, thermocompression energy, and others.

[0006] In connection with wire bonding, it is often desirable to confirm that a portion of the wire has been properly bonded to the bonding location. Wire bonding machines marketed by Kulicke and Soffa Industries, Inc. often utilize a "BITS" process (i.e., a weld integrity testing system) to confirm that the proper wire bond portion has been formed. International Patent Application Publication No. WO 2009 / 002345 describes exemplary details of such a process and related systems, the entire contents of which are incorporated herein by reference.

[0007] Therefore, it would be desirable to provide improved methods of determining the welding condition of a portion of a wire arc (eg, to determine whether the portion of the wire arc has properly welded to a weld location). Summary of the invention

[0008] According to an exemplary embodiment of the present invention, a method for determining a welding condition between a wire and at least one welding position of a workpiece is provided. The method comprises the following steps: (a) using a welding tool of a wire bonding machine to weld a portion of the wire to a welding position of the workpiece; (b) determining a motion profile (thus providing a predetermined motion profile) of the welding tool for determining whether the portion of the wire is welded to the welding position, the motion profile being configured to cause the wire to break during the motion profile if the portion of the wire is not welded to the welding position; and (c) moving the welding tool along the motion profile to determine whether the portion of the wire is welded to the welding position.

[0009] Such a method can also be used to check the welding conditions of multiple parts of the wire material welded to the corresponding multiple welding positions of the workpiece. In such a case, steps (b) and (c) described in the previous paragraph can be repeated for each of the multiple parts of the wire material to determine whether each of the multiple parts of the wire material is welded to their corresponding welding positions of the workpiece.

[0010] According to another exemplary embodiment of the present invention, another method for determining a welding condition between a wire and at least one welding position of a workpiece is provided. The method comprises the following steps: (a) welding a portion of the wire to a welding position of the workpiece using a welding tool of a wire bonding machine; (b) during step (a), detecting at least two of (i) a deformation feature associated with welding the portion of the wire, (ii) a welding force feature associated with welding the portion of the wire, and (iii) a transducer feature of a transducer of the wire bonding machine; and (c) determining a welding condition of the portion of the wire welded to the welding position in step (a) using the information detected in step (b). BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The present invention is 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. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. The drawings include the following figures:

[0012] Figures 1A-1H is a series of block diagram views of a wire bonding system illustrating a method of determining a bonding position of a bonding portion of a wire according to an exemplary embodiment of the present invention;

[0013] Figures 2A-2F is a series of block diagram views of a wire bonding system illustrating a method of determining that a bonding portion of a wire is not bonded to a bonding location according to an exemplary embodiment of the present invention;

[0014] FIG. 3 is a block diagram of a conventional wire bonding machine for illustrating certain exemplary methods according to the present invention; and

[0015] Figure 4 is a flow chart illustrating an exemplary method of determining a welding condition of a portion of a wire being welded to a bonding location on a wire bonding machine according to various exemplary embodiments of the present invention. DETAILED DESCRIPTION

[0016] According to some exemplary embodiments of the present invention, real-time bond lift detection of a workpiece (e.g., a semiconductor device, such as a memory based semiconductor device, a stacked die memory device, etc.) is provided. In such a memory based semiconductor device, a portion of a wire may be configured as at least one of a power lead or a ground lead of the memory based semiconductor device.

[0017] Aspects of the present invention are particularly applicable to multi-stitch bonding processes (i.e., wire arcs that include more than two bonding portions - for example, wire arcs that include three, four, five or more bonding portions). For multi-stitch die-to-die bonding, detecting stitch bond lift can be difficult due to the very low inter-die impedance.

[0018] Aspects of the present invention will force the weld wire to break if the weld is not properly attached to the weld location. Detecting a broken wire can be accomplished using existing detection systems (e.g., BITS systems) that detect electrical continuity (or lack thereof). Such detection is easy for a broken wire, which presents a high impedance indicating that the wire is not secured to the proper weld location.

[0019] Therefore, determining whether the wire is disconnected can be performed using a detection system of the wire bonding machine. For example, the detection system detects whether a conductive path is established between (a) the wire and (b) a portion of the wire bonding machine. The conductive path includes at least one of: (a) a wire clamp for clamping the wire, (b) a wire reel for supplying the wire to a bonding tool, (c) a deflector element for assisting in positioning the wire between the wire reel and the bonding tool, and (d) an air guide system for assisting in positioning the wire between the wire reel and the bonding tool. The detection system can detect whether the conductive path is established by detecting at least one of: (a) a predetermined current in the conductive path, (b) a predetermined change in capacitance between the conductive path and a ground connection of the wire bonding machine, and (c) a predetermined phase shift of a current flowing in the conductive path.

[0020] According to certain exemplary embodiments of the present invention, a method for determining / detecting the welding condition of a wire connection on a workpiece (e.g., whether a portion of the wire is properly welded, whether a portion of the wire is not properly welded, etc.) is provided. For example, such a method can be implemented in real time on a production wire bonding system (e.g., a wire bonding machine).

[0021] Reference now Figures 1A-1H , a wire bonding system 100 is provided. The wire bonding system 100 includes a support structure 102 (eg, a heating block, anvil, etc.) for supporting a workpiece 103. Figure 1A As shown in FIG. 1 , workpiece 103 includes substrate 104 and a plurality of stacked semiconductor dies 106 a , 106 b , and 106 c .

[0022] exist Figures 1A-1H In the embodiment, the wire bonding system 100 further includes a wire bonding tool 108 (e.g., a capillary wire bonding tool), a wire clamp 110, and a detection system 114 (e.g., a BITS system). A length of wire 112 is provided to the wire bonding tool 108 through the wire clamp 110. Figure 1A , a ball 112a (ie, a portion of the wire 112) is seated at the end of the wire bonding tool 108. Figure 1E , an electrical connection 113 is provided between the wire clamp 110 and the detection system 114. As known to those skilled in the art, using the detection system 114, the wire clamp 110 is in a state such as Figure 1E With the detection system 114 in the closed position shown in , electrical continuity may be detected between the detection system 114 and a portion of the wire being welded to the workpiece 103 .

[0023] Using various methods of the present invention, real-time feedback regarding the bonding condition of a portion of a wire arc (or other portion of the wire, such as a conductive bump) can be provided to a wire bonding system.

[0024] exist Figure 1A In FIG. 1 , the ball 112 a is bonded to a bonding location (eg, a die pad) of the die 106 c. Figure 1B At , the ball 112a has been transformed into the welding wire portion 112b. Figure 1B At 112a, a portion of the wire 112 extends from the welding wire portion 112b and the welding tool 108. Figure 1C , the wire 112 has been further formed to include a bend 112c, and another wire bond portion is being formed between the bonding location of the wire 112 and the die 106b. Figure 1D 1 , the bond wire portion is shown as bond wire portion 112d, and another length of wire 112 extends from bond wire portion 112d to bonding tool 108 in a manner that includes bend 112e.

[0025] At this time, it is desirable to determine the welding condition of the welding wire portion 112d (for example, whether the welding wire portion 112d is properly welded to the welding position of the tube core 106b). Figure 1E As shown in , with the wire clamp 110 in the closed position, the wire bonding tool 108 moves along a predetermined motion curve (wherein the motion curve may include a predetermined direction, distance, angle, etc.) (see the dotted line of the bonding tool 108 that has moved along the motion curve, which stretches the wire, as shown in dotted lines, but does not break the bonding wire portion 112d). Figure 1E As shown in , the bonding wire portion 112d is still properly bonded to the bonding location of the tube die 106b, which is detected by the detection system 114. Figure 1F-1G At Figure 1H The remainder of the wire (marked as wire arc 116) including the welded wire portion 112f is formed.

[0026] Figures 2A-2F The figure shows Figures 1A-1H Similar components in the examples above have different results. Figure 2E As shown in FIG. 1 , the welding wire portion 112d (shown in FIG. Figure 2D ) is not attached to the soldering position of the tube core 106b, or follows a predetermined motion curve (ie, Figure 2E The welding tool 108 is pulled away from the welding position in other ways (as shown by the dashed arrow in FIG. 1 ). When the welding tool 108 moves further along the motion curve, as shown in FIG. Figure 2F As shown in FIG. 1 , a wire break 112g occurs, as detected by the detection system 114. Since the wire break 112g is detected by the detection system 114, the welding condition of the welding wire portion 112d is known to be "unacceptable" or "not welded" or "lifted-off" or some similar condition.

[0027] Therefore, in Figures 1A-1H In FIG. 1 , it has been determined that the bonding wire portion 112 d has a bonding position to the tube core 106 b. Figures 2A-2F In FIG. 1 , it has been determined that the bond wire portion 112 d is not bonded to the bonding location of the die 106 b .

[0028] exist Figures 1A-1H Neutral Figures 2A-2F In FIG. 1 , only one weld portion (i.e., weld portion 112d) is checked using the welding condition checking technique of the invention. However, it is understood that multiple weld portions can be checked using the invention. For example, Figure 1H Each weld portion of the wire arc 116 shown in FIG. 1 (ie, weld wire portion 112b, weld portion 112d, and weld portion 112f) may utilize a motion profile (eg, in combination with Figure 1EThe motion curves shown and described) are checked.

[0029] In a specific example, the welding wire portion 112b is formed (see Figure 1B ), the welding condition of the welding wire portion 112b may be checked using a predetermined motion curve. After checking the welding condition of the welding wire portion 112b, the welding portion 112d may be formed (see Figure 1D After the welding portion 112d is formed, Figure 1E The predetermined motion curve is used to check the welding condition of the welding wire portion 112d. After checking the welding condition of the welding wire portion 112d, the welding portion 112f can be formed (see Figure 1G ). After the weld portion 112f is formed (but before the wire arc 116 is separated from the wire source), the predetermined motion curve can be used to check the welding condition of the welded wire portion 112f. Therefore, it is clear that the above combined Figures 1A-1H and Figures 2A-2F The described inventive technique may be used to verify the weld condition of any number of weld portions of a wire arc.

[0030] It will be appreciated that according to aspects of the present invention (such as in Figures 1A-1H and Figures 2A-2F ), the following steps may be included, namely: determining a motion curve of the welding tool for determining whether a portion of the wire is welded to the welding position. That is, in the welding portion (such as Figure 1D Before the welding portion 112d in FIG. 112b , the motion curve will be determined. That is, before following the motion curve (such as Figure 1E Such a motion profile may be configured to cause the wire to break during the motion profile if a portion of the wire is not welded to the welding location (see, for example, Figure 2F The motion profile may be determined through a trial and error process (or other process, such as an iterative process) using information relevant to the specific application (e.g., weld positions of various weld portions of the wire arc, wire looping parameters, etc.).

[0031] Figures 1A-1H and Figures 2A-2FThe figure illustrates some exemplary methods for determining the welding condition of a welded portion of a wire (e.g., a wire arc) welded to a workpiece. However, the present invention also contemplates other methods for determining the welding condition of a welded wire portion. As described below, in other exemplary embodiments of the present invention, information detected by a wire bonding machine during a wire bonding process (e.g., a deformation feature associated with a portion of the welding wire, a welding force feature associated with a portion of the welding wire, a transducer feature of a transducer of a wire bonding machine, etc.) can also be used to determine the welding condition between the wire and at least one welding position of the workpiece.

[0032] FIG. 3 is a simplified wire bonding machine 100a (which can be used with Figures 1A-1H Wire bonding machine 100a is a side view of a wire bonding machine (similar or identical to wire bonding system 100 of the present invention) that can be used to detect the information described in the immediately preceding paragraph and in other portions of this application. Wire bonding machine 100a includes a support structure 102 (e.g., a heating block, anvil, etc.) for supporting semiconductor element 304 during a wire bonding operation. Figure 1A In the illustrated example in FIG, the semiconductor component 304 includes a plurality of semiconductor dies 304a on a lead frame 304b. Of course, other types of semiconductor components (eg, such as memory-based semiconductor devices, stacked die devices, etc.) are also contemplated within the scope of the present invention.

[0033] The wire bonding machine 100a also includes a wire bonding tool 108 (e.g., a capillary wire bonding tool, etc.) for bonding a wire portion to a semiconductor element 304. As will be appreciated by those skilled in the art, the wire bonding tool 108 (carried by the bonding head assembly 300) can be moved along multiple axes of the wire bonding machine 100a to perform a wire bonding operation. For example, by movement of the bonding head assembly 300, the wire bonding tool 108 moves along an x-axis and a y-axis. The linkage 300a is carried by the bonding head assembly 300 and the wire bonding tool 108. The linkage 110a is configured for movement along the z-axis of the wire bonding machine 100a. Additional elements carried by the bonding head assembly 300 (and specifically by the linkage 300a) include: a movable portion of a z-axis motor 300a1 that moves along the z-axis with the linkage 300a; a transducer 300a2 for carrying the wire bonding tool 108 and for providing an ultrasonic scrub to the end portion 108a of the wire bonding tool 108; a force sensor 300a3 for sensing the applied bonding force during the wire bonding operation; and a z-axis position detector 300a4 (e.g., a z-axis encoder). As known to those skilled in the art, the z-axis position detector 300a4 detects the z-axis position of the linkage 300a (and therefore the relative z-axis position of the wire bonding tool 108) and provides data corresponding to the z-axis position (e.g., in real time) to the computer 302 of the wire bonding machine 100a. Thus, the computer 302 has information related to the z-axis position of the bonding tool 108 moving through it. Certain information from each of the z-axis motor 300a1, transducer 300a2, force sensor 300a3, and z-axis position detector 300a4 may be provided to the computer 302 (as shown by the arrows extending from the welding head assembly 300 to the computer 302). The computer 302 may also provide information (e.g., instructions) back to the elements of the welding head assembly 300 (as shown by the arrows extending from the computer 302 to the welding head assembly 300). In a specific example, in a closed-loop configuration, the computer 302 provides control signals to one z-axis motor 300a1 and / or transducer 300a2.

[0034] Figure 4 Flowcharts are flow charts illustrating exemplary methods according to the present invention. As those skilled in the art will appreciate, certain steps included in the flow charts may be omitted; certain additional steps may be added; and the order of the steps may be altered from the order illustrated - all within the scope of the present invention.

[0035] Figure 4 is a flow chart illustrating an exemplary method for determining a welding condition of a portion of a wire material welded to a welding location on a wire bonding machine, such as Figures 1A-1H and Figures 2A-2F3 , or other wire bonding machines within the scope of the present invention.

[0036] At step 400, a relationship is determined between (i) a feature to be detected during a wire welding process and (ii) a welding condition of a portion of the wire to be welded to a workpiece. The feature may include, for example, any two or more of a deformation feature associated with welding a portion of the wire, a welding force feature associated with welding a portion of the wire, and a transducer feature of a transducer of a wire welding machine. The welding condition may include a simple condition (e.g., "welded" or "not welded"), or may be slightly more specific (e.g., "good" weld, "acceptable" weld, "unacceptable" weld, "stripping state", and other labels determined by a user). Depending on the welding condition, the operation may continue (e.g., in the case of a good weld or an acceptable weld), the operation may stop (e.g., in the case of an "unacceptable" weld or "stripping state", the wire welding operation may stop), and an alarm or other notification may be provided (e.g., in the case of an acceptable weld, an unacceptable weld, a stripping state, etc.). The specific tag (welding condition) applied and the action taken in connection with that tag (eg, continue the wire bonding operation, stop the wire bonding operation, provide an alert for other notifications, etc.) may be customized to the application or user.

[0037] In a more specific example, testing / experiments may be completed on one or more wire bonding applications (e.g., using a specific die, a specific wire material, specific wire bonding parameters that may be optimized using a closed-loop process, specific wire arcing parameters that may be optimized using a closed-loop process, etc.). Through this testing / experimentation, the values ​​of the aforementioned characteristics (e.g., deformation characteristics, welding force characteristics, transducer characteristics, etc.) may be detected and recorded. Various ranges for each of the characteristics and combined ranges for multiple characteristics may be determined.

[0038] For example, testing / experiments may be used to provide a range for each welding condition (eg, good weld, acceptable weld, unacceptable weld, debonding, etc.) Similarly, each welding condition may specify a range of combinations of features.

[0039] In a specific example, let us assume that each of the deformation feature, welding force feature, and transducer feature is monitored. A "good weld" welding condition can be applied to a situation where each of these three features falls within a predetermined range for the feature. When one or more of these three features falls within a predetermined range that is not in a "good" range but in an "acceptable" range for the feature, an "acceptable weld" welding condition can be applied. When one or more of these three features falls within a predetermined range that is not in a "good" range or an "acceptable" range but in an "unacceptable" range for the feature, an "unacceptable weld" welding condition can be applied. And so on.

[0040] At step 402, a portion of the wire is welded to a welding location of a workpiece using a welding tool of a wire bonding machine. Figure 1F The figure shows the wire arc 116 (to be formed) of the bonding position to be bonded to the tube die 106b. Figure 1H ) as shown in FIG. 1 ) of the welding wire portion 112d.

[0041] At step 404a, a deformation feature associated with the welded portion of the wire is detected during step 402. The deformation feature is associated with a vertical deformation of a portion of the wire during step 402 as measured by a z-axis position detector (e.g., see z-axis position detector 300a4 in FIG. 3 ). The deformation can be considered as the measured deformation between (i) the wire portion contacting the welding location to (ii) the completion of the welding process of step 402. The deformation feature can be associated with a single value acquired during step 402 (i.e., a single z-axis measurement / value), or can be associated with a series of values ​​acquired during step 402 (i.e., a series of measurements / values ​​relative to time, such as a deformation curve).

[0042] At step 404b, a welding force characteristic associated with welding a portion of the wire is detected. The welding force characteristic may be associated with a welding force measured by at least one of (i) a force sensor in a welding head of a wire bonding machine (e.g., see force sensor 300a3 in FIG. 3 ) and (ii) a z-axis motor characteristic of a z-axis motor of a wire bonding machine (see z-axis motor 300a1 in FIG. 3 ). The welding force characteristic may be associated with a single value acquired during step 402 (i.e., a single welding force measurement / value), or may be associated with a series of values ​​acquired during step 402 (i.e., a series of measurements / values ​​relative to time, such as a welding force curve).

[0043] At step 404c, the transducer characteristics of the transducer of the wire bonding machine are detected. As will be appreciated by those skilled in the art, conventional wire bonding machines include an ultrasonic transducer carried by a bonding head assembly. The ultrasonic transducer is typically carried by a wire bonding tool (e.g., see Figures 1A-1H 402) and applying ultrasonic scrubbing to the end portion of the wire bonding tool to bond the wire portion to the bonding location. According to the present invention, the transducer feature may be associated with any of a plurality of features such as, for example, (i) an impedance of the transducer and (ii) an electrical feature of the transducer (e.g., a voltage measurement, a current measurement, etc.). The transducer feature may be associated with a single value acquired during step 402 (i.e., a single transducer measurement / value), or may be associated with a series of values ​​acquired during step 402 (i.e., a series of measurements / values ​​relative to time, such as a transducer curve).

[0044] At step 406, using the information detected in at least two of steps 404a, 404b, and 404c (e.g., using deformation features and welding force features, using deformation features and transducer features, using welding force features and transducer features, using all three of deformation features and welding force features and transducer features), the welding condition of a portion of the wire material welded to the welding position in step 402 is determined. As described above, the welding condition may be a "good" weld, an "acceptable" weld, an "unacceptable" weld, a "peeling state," or any other welding condition.

[0045] At step 408, the plurality of portions of the wire are welded to the corresponding plurality of welding positions of the workpiece, and steps 404 (including at least two of steps 404a, 404b, and 404c) and step 406 are repeated for each of the plurality of portions of the wire to determine whether each of the plurality of portions of the wire is welded to their corresponding welding positions of the workpiece. Figures 1A-1H , each of the weld wire portions (ie, weld wire portions 112b, 112d, and 112f) may be checked using steps 404 and 406 after forming a particular weld wire portion and before forming the next weld wire portion.

[0046] Although the present invention is illustrated with respect to a particular workpiece, the present invention is not limited thereto. Figures 1A-1H and Figures 2A-2F The stacked die application in FIG. 1 and the simple semiconductor die / lead frame application in FIG. 3 are merely exemplary workpieces. Any type of workpiece that may contain bond wires may be employed.

[0047] Although the present invention is illustrated with respect to a certain wire arc shape, the present invention is not limited thereto. Aspects of the present invention can be used to detect welding (or non-welding, or another welding condition) of any wire portion, such as, for example: a stud bump, a simple wire arc including only a first welding portion and a second welding portion, a complex wire arc including multiple levels and devices, etc.

[0048] Still additionally, it should be understood that if the wire arc includes multiple welding portions, any or all of these welding portions can be checked for proper welding using aspects of the present invention. For example, conventional techniques may be sufficient for detecting proper welding of certain welding portions, while aspects of the present invention may be used for other welding portions.

[0049] It will be appreciated that data associated with one or more features may also be stored in a memory (e.g., a memory of the wire bonding machine, or a remote memory) for later analysis (e.g., to confirm that the ranges for each welding condition are correct when analyzing a particular workpiece on which a wire bonding operation has been completed).

[0050] While the invention is 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 method for determining a welding condition between at least one welding position of a wire and a workpiece, the method comprising the following steps: (a) using a welding tool of a wire bonding machine to weld a portion of the wire material to a welding position of the workpiece; (b) determining a motion profile of a welding tool for determining whether a portion of the wire is welded to a welding location, the motion profile being configured to cause the wire to break during the motion profile if the portion of the wire is not welded to the welding location; and (c) moving the wire bonding tool along the motion curve to determine whether a portion of the wire material is bonded to the bonding position.

2. The method of claim 1, wherein: The workpiece is a memory-based semiconductor device.

3. The method of claim 2, wherein: The wire is configured as at least one of a power lead or a ground lead of the memory-based semiconductor device.

4. The method of claim 1, wherein: Step (c) includes determining whether the wire is broken during the motion profile to determine whether the portion is welded to the welding location.

5. The method of claim 4, wherein: Determining whether the wire is disconnected is performed using a detection system of the wire bonding machine that detects whether a conductive path is established between (a) the wire and (b) a portion of the wire bonding machine.

6. The method of claim 5, wherein: The conductive path includes at least one of: (a) a wire clamp for clamping the wire, (b) a wire reel for supplying the wire to the bonding tool, (c) a diverter element for assisting in positioning the wire between the wire reel and the bonding tool, and (d) an air guide system for assisting in positioning the wire between the wire reel and the bonding tool.

7. The method of claim 6, wherein: The detection system detects whether the conduction path is established by detecting at least one of: (a) a predetermined current in the conduction path, (b) a predetermined change in capacitance between the conduction path and a ground connection of the wire bonding machine, and (c) a predetermined phase shift of the current flowing in the conduction path.

8. The method of claim 1, wherein: Multiple portions of the wire are welded to corresponding multiple welding locations of the workpiece, and wherein steps (b) and (c) are repeated for each of the multiple portions of the wire to determine whether each of the multiple portions of the wire is welded to their corresponding welding locations of the workpiece.

9. A method for determining a welding condition between at least one welding location of a wire and a workpiece, the method comprising the steps of: (a) using a welding tool of a wire bonding machine to weld a portion of the wire material to a welding position of the workpiece; (b) during step (a), detecting at least two of (i) a deformation characteristic associated with welding a portion of the wire, (ii) a welding force characteristic associated with welding a portion of the wire, and (iii) a transducer characteristic of a transducer of a wire bonding machine; as well as (c) determining a welding condition of a portion of the wire material welded to the welding position in step (a) using the information detected in step (b).

10. The method of claim 9, wherein: The workpiece is a memory-based semiconductor device.

11. The method of claim 10, wherein: The wire is configured as at least one of a power lead or a ground lead of the memory-based semiconductor device.

12. The method of claim 9, wherein: Multiple portions of the wire are welded to corresponding multiple welding locations of the workpiece, and wherein steps (b) and (c) are repeated for each of the multiple portions of the wire to determine whether each of the multiple portions of the wire is welded to their corresponding welding locations of the workpiece.

13. The method of claim 9, wherein: The information used to determine whether a portion of the wire material is welded to the welding position in step (c) includes deformation characteristics and welding force characteristics.

14. The method of claim 9, wherein: The information used to determine whether a portion of the wire is welded to the welding position in step (c) includes deformation characteristics and transducer characteristics.

15. The method of claim 9, wherein: The information used in step (c) to determine whether a portion of the wire is welded to the welding position includes transducer characteristics and welding force characteristics.

16. The method of claim 9, wherein: The information used to determine whether a portion of the wire is welded to the welding position in step (c) includes deformation characteristics, welding force characteristics and transducer characteristics.

17. The method of claim 9, wherein: The deformation characteristic is related to a vertical deformation of a portion of the wire during step (b) as measured by a z-axis position detector.

18. The method of claim 9, wherein: The weld force characteristic is related to a weld force measured by at least one of (i) a force sensor in a weld head of the wire bonder and (ii) a z-axis motor characteristic of a z-axis motor of the wire bonder.

19. The method of claim 9, wherein: The transducer characteristic is related to at least one of (i) an impedance of the transducer and (ii) an electrical characteristic of the transducer.

20. The method of claim 9, wherein: The deformation characteristic is associated with a single value obtained during step (b).

21. The method of claim 9, wherein: The weld force characteristic is related to a single value obtained during step (b).

22. The method of claim 9, wherein: The transducer characteristic is associated with a single value obtained during step (b).

23. The method of claim 9, wherein: The deformation characteristic is associated with a series of values ​​obtained during step (b).

24. The method of claim 9, wherein: The weld force characteristic is related to a series of values ​​obtained during step (b).

25. The method of claim 9, wherein: The transducer characteristic is related to a series of values ​​obtained during step (b).

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