A method for determining and / or calibrating the cutter height of a wedge bonding apparatus, and related wedge bonding apparatus.

Abstract

A method for determining a cutter height of a wedge bonding apparatus is provided, the method comprising: (a) lowering a wedge bonding tool towards a surface on a wedge bonding apparatus, (b) determining a first height measurement when the wedge bonding tool contacts the surface, (c) lowering a cutter of the wedge bonding apparatus relative to the wedge bonding tool, (d) determining a second height measurement when the cutter contacts the surface, and (e) determining a cutter height using the first height measurement and the second height measurement.

Description

Technical Field

[0001] (Cross - Reference to Related Applications) This application claims the benefit of U.S. Provisional Application No. 63 / 191,286, filed on May 20, 2021, the content of which is incorporated herein by reference.

Background Art

[0002] The present invention relates to a method for determining and / or calibrating the height of a cutter of a wedge bonding apparatus and a related wedge bonding apparatus.

[0003] In the semiconductor packaging industry and other industries that require electrical interconnects, wire and ribbon bonding using wire bonding machines is widely adopted. In connection with the wire and ribbon bonding operations, various types of energy (e.g., ultrasonic energy, thermo - sonic energy, thermo - compressive energy, etc.) are used to bond the ends of the wire / ribbon to a first bonding position. After the first bond is formed at the first bonding position, a length of the wire / ribbon is extended to a second bonding position, and then the second bond is formed at the second bonding position. A wire loop is a structure that includes at least a first joint and a second joint.

[0004] Exemplary conductive materials used for wires / ribbons in conventional wire bonding (e.g., ball bonding, wedge bonding, ribbon bonding, etc.) include, among others, aluminum, copper, and gold. The following are prior art documents related to the invention of this application (including documents cited in the international phase after the international filing date and documents cited when the application entered the national phase in other countries): (Prior art document) (Patent Document) (Patent Document 1) U.S. Patent Application Publication No. 2010 / 0127045 (Patent Document 2) Japanese Unexamined Patent Publication No. 2004-247693 (Patent Document 3) U.S. Patent Application Publication No. 2020 / 0388589 (Patent Document 4) U.S. Patent Application Publication No. 2006 / 0071049 (Patent Document 5) U.S. Patent No. 8,141,765 [Overview of the project] [Problems that the invention aims to solve]

[0005] In wedge bonding and ribbon bonding operations, after forming a wire structure (e.g., a wire loop), the wire or ribbon can be cut using a cutter tool ("cutter"). Such a cutter has a relative height on the wedge bonding apparatus (e.g., relative to the wedge bonding tool). This relative height may change, for example, due to wear and / or replacement of the cutter.

[0006] Therefore, it is desirable to provide an improved method for determining and / or calibrating the cutter height of a wedge bonding apparatus. [Means for solving the problem]

[0007] A method for determining the height of a cutter in a wedge bonding apparatus according to an exemplary embodiment of the present invention is provided. This method comprises the steps of (a) lowering a wedge bonding tool toward a surface on the wedge bonding apparatus; (b) determining a first height measurement when the wedge bonding tool contacts the surface; (c) lowering the cutter of the wedge bonding apparatus toward the wedge bonding tool; (d) determining a second height measurement when the cutter contacts the surface; and (e) determining the cutter height using the first and second height measurements.

[0008] Another exemplary embodiment of the present invention provides a method for determining the cutter height of a wedge bonding apparatus. This method includes the steps of: (a) lowering a wedge bonding tool toward a surface on the wedge bonding apparatus, the surface being integrated with a spring assembly; (b) determining a first height measurement when the wedge bonding tool makes contact with the surface; (c) compressing the spring portion of the spring assembly by further lowering the wedge bonding tool after the wedge bonding tool has made contact with the surface; (d) raising the wedge bonding tool and the surface after step (c), while extending the spring portion until the cutter makes contact with the surface; (e) determining a second height measurement when the cutter makes contact with the surface; and (f) determining the cutter height using the first and second height measurements.

[0009] According to another exemplary embodiment of the present invention, a method for determining the cutter height of a wedge bonding apparatus is provided. This method includes the steps of (a) lowering a wedge bonding tool toward a surface on the wedge bonding apparatus, the surface being integrated with a spring assembly; (b) compressing the spring portion of the spring assembly by further lowering the wedge bonding tool after contact between the wedge bonding tool and the surface; (c) lowering the cutter toward the wedge bonding tool and the surface until the cutter contacts the surface; and (d) determining the height measurement at which the cutter contacts the surface.

[0010] According to another exemplary embodiment of the present invention, a method for determining the cutter height of a wedge bonding apparatus is provided. This method comprises (a) moving a wedge bonding tool relative to at least one of the surfaces on the wedge bonding apparatus, (b) a step of determining a first height measurement when the wedge bonding tool contacts the surface; (c) a step of moving the cutter of the wedge bonding apparatus relative to at least one of the surfaces; (d) a step of determining a second height measurement when the cutter contacts the surface; and (e) a step of determining the cutter height using the first and second height measurements.

[0011] According to another exemplary embodiment of the present invention, a method for determining the cutting profile of a cutter on a wedge bonding apparatus is provided. This method comprises (a) determining the cutter height of the wedge bonding apparatus, and (b) using the cutter height determined in step (a) to determine the cutting profile of the cutter on the wedge bonding apparatus.

[0012] According to another exemplary embodiment of the present invention, a wedge bonding apparatus is provided. Such a wedge bonding apparatus includes the elements referenced above in relation to a method for determining the cutter height of the wedge bonding apparatus. Such a wedge bonding apparatus may include any other elements referenced herein, such as a load cell for detecting contact between a wedge bonding tool (and / or cutter) and a surface, an electrical detection system for detecting electrical conductivity between the wedge bonding tool (and / or cutter) and the surface, and a spring assembly including the surface described herein. [Brief explanation of the drawing]

[0013] This invention is best understood by reading the following detailed description in conjunction with the accompanying drawings. It should be emphasized that, in accordance with common practice, various features in the drawings are not to scale. Conversely, the dimensions of various features have been arbitrarily enlarged or reduced for clarity. The drawings include the following figures: [Figure 1]FIG. 1 is a block side view of a wedge bonding apparatus useful for performing methods related to various exemplary embodiments of the present invention. [Figure 2A-2D] FIGS. 2A-2D are a series of block diagrams showing a method for determining the cutter height of a wedge bonding apparatus according to an exemplary embodiment of the present invention. [Figure 3A-3E] FIGS. 3A-3E are a series of block diagrams showing another method for determining the cutter height of a wedge bonding apparatus according to an exemplary embodiment of the present invention. [Figure 3F-3I] FIGS. 3F-3I are a series of block diagrams showing yet another method for determining the cutter height of a wedge bonding apparatus according to an exemplary embodiment of the present invention. [Figure 4A-4D] FIGS. 4A-4D are a series of block diagrams showing yet another method for determining the cutter height of a wedge bonding apparatus according to an exemplary embodiment of the present invention. [Figures 5A-5D] FIGS. 5A-5D are a series of block diagrams showing a method for determining the cutting profile of a cutter on a wedge bonding apparatus according to an exemplary embodiment of the present invention. [Figure 6] FIGS. 6, 7A-7B, and 8 are flow diagrams showing various methods for determining the cutter height of a wedge bonding apparatus according to various exemplary embodiments of the present invention. [Figure 7A] FIGS. 6, 7A-7B, and 8 are flow diagrams showing various methods for determining the cutter height of a wedge bonding apparatus according to various exemplary embodiments of the present invention. [Figure 7B] FIGS. 6, 7A-7B, and 8 are flow diagrams showing various methods for determining the cutter height of a wedge bonding apparatus according to various exemplary embodiments of the present invention. [Figure 8] FIGS. 6, 7A-7B, and 8 are flow diagrams showing various methods for determining the cutter height of a wedge bonding apparatus according to various exemplary embodiments of the present invention. [Figure 9]FIG. 9 is a flowchart showing a method for determining a cutting profile of a cutter on a wedge bonding apparatus according to an exemplary embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0014] According to certain exemplary embodiments of the present invention, a method is provided for determining and / or calibrating the cutter height (e.g., the relative cutter height of the cutter with respect to the wedge bonding tool) on a wedge bonding apparatus. By accurately knowing the cutter height (e.g., which changes when the cutter is changed in the wedge bonding apparatus), the wedge bonding apparatus can be operated (e.g., programmed) to adjust to the changed value of the cutter height.

[0015] Aspects of the present invention relate to determining the cutter height when changing from a previous cutter to a new cutter in a wedge bonding apparatus (e.g., the cutter may be considered a consumable part). According to other aspects of the present invention, the cutter height can be determined at certain intervals.

[0016] According to certain exemplary aspects of the present invention, instead of a combined value including the distance the cutter must move to start a cut into the wire / ribbon surface and the depth the cutter cuts into the wire / ribbon (which is adjusted each time the cutter blade is replaced), an exemplary method of the present invention (e.g., a cutter calibration method) divides the distance into (i) the calibrated cutter height on the bond tool (the relative height with respect to the cut start point of the wire / ribbon position) and (ii) the actual cut depth into the wire / ribbon. Such an approach allows the value of the cut depth to be an independent variable from the cutter. Thus, the value of the cut depth can be adjusted according to the aging of the cutter.

[0017] Exemplary aspects of the present invention include using force and / or position feedback to calibrate the cutter during setup. Such an approach can be applied to both wire cutting and ribbon cutting processes. Examples: (i) the cutter contacts a load cell following a bond tool—the position of the cutter is read when contact is detected; (ii) the cutter contacts a hard surface following a bond tool using the motor current of a motion control system as a feedback mechanism; (iii) the cutter contacts a hard surface following a bond tool using the tracking error of a motion control system as a feedback mechanism. Of course, other methods are also within the scope of the present invention.

[0018] According to aspects of the present invention, simplified and automated cutter height measurement and / or calibration is provided after cutter replacement. Furthermore, operator influence in determining the cutter height can be eliminated.

[0019] Currently, determining the cutter height is a manual process and heavily relies on operator intervention. The method of the present invention described herein includes automating the determination of the cutter height.

[0020] As used herein, the term “cutter height” refers to the distance between the contact portion of the wedge bonding tool and the tip portion of the cutter. In certain figures herein, the cutter height is labeled “RCH” (relative cutter height). The cutter height can be considered as the relative height between the cutter and the wedge bonding tool. Exemplary ranges of cutter height determined according to aspects of the present invention are 100–2500 microns, and 100–2500 microns, 300–1500 microns, and 400–1200 microns. Of course, different cutter height ranges are also possible.

[0021] According to a particular aspect of the present invention, the cutting profile of a cutter can be determined, and such a cutting profile can utilize the cutter height determined after cutter replacement in a wedge bonding apparatus. The cutting profile includes the amount of cutting applied in a particular application (e.g., cutting depth). The cutting profile may also include other elements such as time and force (e.g., cutting depth versus time, force applied during cutting). Another value that can be used in relation to determining the cutting profile is the height of the portion of the wire extending below the bonding surface of the wedge tool (e.g., see the wire in Figures 5B-5D).

[0022] Figure 1 shows a wedge bonding apparatus 100. As described herein and as will be understood by those skilled in the art, certain elements shown in Figure 1 are optional, and not all apparatus elements shown in Figure 1 are included in each wedge bonding apparatus of the present invention within the scope of the present invention. The wedge bonding apparatus 100 includes a mechanical structure 102 (e.g., a workpiece support structure, or other structure) and a contact structure 104 on the mechanical structure 102. The contact structure 104 includes a surface 104e, which is configured to be used in connection with height measurement relating to various aspects of the present application. The contact structure 104 may be a substrate or workpiece configured to be wire bonded, or a different contact structure (e.g., a calibration station or a measuring station) specifically configured for use relating to the present invention. The contact structure 104 may vary depending on the application (see, for example, contact structure 104' in Figures 2A-2D, contact structure 104'' in Figures 3A-3E and 3F-3I, and contact structure 104'''' in Figures 4A-4D).

[0023] In certain embodiments of the present invention, the contact structure 104 may include other exemplary elements. Examples include: a force (load) sensor 104a (for example, to determine contact between the wedge bonding tool 106 and the surface 104e, and / or to determine contact between the cutter 108 and the surface 104a); an electrical continuity detector 104b (for example, to detect the completion of an electrical circuit including the wedge bonding tool 106 and the surface 104e, to detect contact between them, and / or to detect the completion of an electrical circuit including the cutter 108 and the surface 104e, and / or to detect contact between the cutter 108 and the surface 104e); a spring assembly 104c (for example, see the spring portion 150 of the spring assembly shown in Figures 3A-3E and 3F-3I); and a contact structure motion system 104d (for example, for moving the contact structure along the Z axis, as shown in Figures 4B-4D). The wedge bonding apparatus 100 also includes a bond head assembly 110 that carries a wedge bonding tool 106 (including a working end 106a having a contact surface 106a1) and a cutter 108 (including a cutter tip 108a). The bond head assembly 110 is moved along the Z-axis of the wedge bonding apparatus 100 using a Z-axis motion system 114. The cutter 108 can also be moved along the Z-axis of the wedge bonding apparatus 100 using the Z-axis motion system 114. However, a cutter Z-axis motion system 116 for moving the cutter along the Z-axis may be optionally included (instead of or in addition to the use of the Z-axis motion system 114). The bond head assembly 110 includes a transducer 110a and one or more of the following: a force (load) sensor 110b (for example, to determine contact between the wedge bonding tool 106 and the surface 104e, and / or to determine contact between the cutter 108 and the surface 104e), an electrical continuity detector 110c (for example, to sense the completion of an electrical circuit including the wedge bonding tool 106 and the surface 104e, to determine contact between them, and / or to sense the completion of an electrical circuit including the cutter 108 and the surface 104e, to determine contact between them), a z-axis position detector 110d (for example, a z-axis encoder for determining the height of a part of the z-axis motion system), an overtravel Z-axis position detector 110e (for example, a Z-axis encoder for determining the height of a part of the overtravel mechanism of the Z-axis motion system), and an overtravel mechanism 110f. As those skilled in the art will understand, the overtravel mechanism 110f provides a constant, independent movement of the cutter relative to the wedge bonding tool. For example, as described below, the overtravel mechanism 110f allows the cutter 108 to move downward independently of the wedge bonding tool 106, as shown between Figures 2C and 2D. The overtravel mechanism 110f allows the wedge bonding tool 106 to move upward independently of the cutter 108, as shown between Figures 3D and 3E. The overtravel mechanism 110f allows the wedge bonding tool 106 to move independently of the cutter 108, as shown between Figures 3H and 3I. Furthermore, the overtravel mechanism 110f allows the wedge bonding tool 106 to move upward independently of the cutter 108, as shown between Figures 4C and 4D. The wedge bonding apparatus 100 also includes a computer 112 (representing one or more local or remote computing systems). The computer 112 communicates with the Z-axis motion system 114 and elements of the bond head assembly 110 for data acquisition and control. For example, the computer 112 receives information (e.g., from an encoder) related to the measurement of the Z-axis height used to determine the cutter height.

[0024] Figures 2A–2D are a series of block diagrams illustrating how the cutter height of the wedge bonding apparatus 100 is determined. As shown in Figure 2A, the wedge bonding tool 106 (only the tip portion 106a is shown in Figure 2A) and the cutter 108 are positioned on the surface 104e' of the contact structure 104'. Although not fully visible in Figure 2A, the wedge bonding tool 106 defines a groove 106b with a vertex 106b1 for receiving the wire. In Figure 2B, the wedge bonding tool 106 is lowered toward the surface 104e' (e.g., using a z-axis motion system 114). In Figure 2C, the contact surface 106a1 of the wedge bonding tool 106 is in contact with the surface 104e'. At this point, a first height measurement (h1) is determined (e.g., using a z-axis position detector 110d, such as an encoder in the z-axis motion system). Next, the cutter 108 descends relative to the wedge bonding tool 106 (for example, using the Z-axis motion system 114 and the overtravel mechanism 110f). For example, the overtravel mechanism 110f (see, for example, Figure 1) can cause the cutter 108 to descend after contact as shown in Figure 2C. In Figure 2D, the tip portion 108a of the cutter 108 contacts the surface 104e'. A second height measurement (h2) is determined at this point (for example, using a z-axis position detector 110d such as an encoder in the z-axis motion system). Using h1 and h2, the height of the cutter can be determined.

[0025] In another example, the force applied by the Z-axis motion system 114 may be interrupted so that the spring force of the spring portion 150 pushes upward. In either case, the spring portion 150 extends until the tip portion 108a of the cutter 108 contacts the surface 104e'', as shown in Figure 3E. A second height measurement (h2) is determined at this point (for example, using a z-axis position detector 110d such as an encoder of the z-axis motion system). Using h1 and h2, the height of the cutter can be determined.

[0026] In the embodiments shown in Figures 3A-3E, a first height measurement and a second height measurement are determined and used to provide the cutter height. However, as shown in Figures 3F-3I, in certain implementations it is possible to measure the cutter height using a single height measurement (for example, since measurements such as overtravel measurements may start at a known reference value or a zero reference value). Referring particularly to Figure 3F, the wedge bonding tool 106 (only the tip portion 106a is shown in Figure 3A) and the cutter 108 are positioned on the surface 104e'' of the contact structure 104''. Although not fully visible in Figure 3F, the wedge bonding tool defines a groove 106b having a vertex 106b1 for receiving the wire. In Figure 3F, a spring assembly (including a spring portion 150) is integrated with the surface 104e''. More specifically, the spring portion 150 is provided between the contact structure 104'' and the mechanical structure 102''. In Figure 3G, the wedge bonding tool 106 is descending toward the surface 104e'' (for example, using the z-axis motion system 114). In Figure 3H, the contact surface 106a1 of the wedge bonding tool 106 contacts the surface 104e''. At this point, the wedge bonding tool 106 descends further to compress the spring portion 150. Subsequently, the cutter 108 is descended relative to the wedge bonding tool 106 and the surface 104e'' until the tip 108a of the cutter 108 contacts the surface 104e'', as shown in Figure 3I. A height measurement (h1) is determined at this point (for example, using a z-axis position detector 110d such as an encoder or overtravel encoder of the z-axis motion system). This height measurement can be considered as the height of the cutter or used to derive the height of the cutter.

[0027] Figures 4A–4D are a series of block diagrams illustrating how the cutter height of the wedge bonding apparatus 100 is determined, and the wedge bonding apparatus includes a contact structure motion system 104d (see, for example, Figure 1) for moving the contact structure 104''''. In Figure 4A, the wedge bonding tool 106 (only the tip portion 106a is shown in Figure 4A) and the cutter 108 are positioned on the surface 104e'''' of the contact structure 104''''. Although not fully visible in Figure 4, the wedge bonding tool 106 defines a groove 106b having an apex 106b1 for receiving the wire. In Figure 4B, the contact structure 104'''' is lifted toward the wedge bonding tool 106 (for example, using the contact structure motion system 104d). In Figure 3C, the contact surface 106a1 of the wedge bonding tool 106 has a contact surface 104e'''. At this point, a first height measurement (h1) is determined (for example, using a z-axis position detector 110d such as an encoder in the z-axis motion system). Next, the contact structure 104''' rises further while in contact with the wedge bonding tool 106 (by the overtravel mechanism 110f). That is, the contact structure 104'' rises further using the contact structure motion system 104d until the surface 104e''' contacts the tip portion 108a of the cutter 108 (as shown in Figure 4D). A second height measurement (h2) is determined at this point (for example, using a z-axis position detector 110d such as an encoder in the z-axis motion system). Using h1 and h2, the height of the cutter can be determined.

[0028] According to the present invention, the cutter height can be used in relation to subsequent cutting operations in a wedge bonding apparatus (for example, in relation to a value for the cutter depth). In certain examples, the cutter height can be used in relation to providing a cutting profile for the cutter on a wedge bonding apparatus. Figures 5A–5D show exemplary methods for determining such a cutting profile. Figure 5A shows how the cutter height is determined (for example, using methods such as those in Figures 2A–2D, 3A–3E, 3F–3I, 4A–4D, or any other method including methods within the scope of the present invention).

[0029] After the cutter height is determined, the wire 118 is engaged with the wedge bonding tool 106. In Figure 5B, the wedge bonding tool 106 (only the tip portion 106a is shown in Figure 5B) and the cutter 108 are positioned on the surface 120a of the structure 120. Although not fully shown in Figure 5B, the wedge bonding tool 106 defines a groove 106b with a vertex 106b1 for receiving the wire 118. At this position, the wire 118 engages with the wire bonding tool 106. At this position, a portion of the wire 118 extends below the contact surface 106a1 of the wedge bonding tool 106. The dimensions of this portion of the wire 118 in Figure 5B are labeled as hwire in Figure 1. In Figure 5C, the wedge bonding tool 106 is descending toward the surface 120a (e.g., using the z-axis motion system 114). In Figure 5D, the wire 118 has a contact surface 120a. At this point, a height measurement is determined (for example, using a z-axis position detector 110d such as an encoder in a z-axis motion system). Using this height measurement and the cutter height (including at least a first and second height measurement determined in connection with the determination of the cutter height), the cutting profile can be determined. As will be understood by those skilled in the art, the structure 120 (including surface 120a) shown in Figures 5B-5D can be any structure (and corresponding surface) on the wedge bonding apparatus. In fact, if necessary, the structure 120 may be a contact structure 104 and surface 120a may be a contact surface 104e (see, for example, Figure 1).

[0030] Figures 6-8 are flowcharts illustrating various exemplary methods for determining the cutter height of a wedge bonding apparatus according to the present invention. They are flowcharts illustrating exemplary methods for determining the cutting profile of a cutter on a wedge bonding apparatus according to the present invention. As will be understood by those skilled in the art, certain steps included in the flowcharts may be omitted, certain additional steps may be added, and the order of the steps may be changed from the illustrated order, all of which are within the scope of the present invention.

[0031] Referring here to Figure 6, in step 600, the wire is disengaged from the wedge bonding tool. That is, if the wire is engaged with the wedge bonding tool (e.g., under the working end of the wedge bonding tool), the wire is removed from that position. In step 602, the bond head (e.g., mounting the wedge bonding tool and cutter) is moved to the test position (e.g., using its xyz motion system). The test position can be, for example, any desired position on the wedge bonding apparatus. In step 604, the wedge bonding tool is lowered toward the surface on the wedge bonding apparatus (e.g., see Figure 2B). In step 606, a first height measurement is determined when the wedge bonding tool contacts the surface (e.g., see the determination of height h1 in Figure 2C). In step 608, the cutter is lowered toward the wedge bonding tool, and in step 610, a second height measurement is determined when the cutter contacts the surface (e.g., see the determination of height h2 in Figure 2D). In step 612, the cutter height is determined using the first height measurement and the second height measurement (for example, by calculating the difference between the first height measurement and the second height measurement).

[0032] Referring here to Figure 7A, in step 700, the wire is disengaged from its engagement with the wedge bonding tool. That is, if the wire is engaged with the wedge bonding tool (e.g., under the working end of the wedge bonding tool), the wire is removed from that position. In step 702, the bond head (e.g., mounting the wedge bonding tool and cutter) is moved to the test position (e.g., using its xyz motion system). The test position can be, for example, any desired position on the wedge bonding apparatus. In step 704, the wedge bonding tool is lowered toward a surface integrated with the spring assembly on the wedge bonding apparatus (e.g., see Figure 3B). In step 706, a first height measurement is determined when the wedge bonding tool contacts the surface (e.g., see the determination of height h1 in Figure 3C). In step 706, a first height measurement is determined when the wedge bonding tool contacts the surface (e.g., see the determination of height h1 in Figure 3C). In step 708, the spring portion of the spring assembly is compressed by further lowering the wedge bonding tool after it has made contact with the surface (see, for example, Figure 3D). In step 710, after step 708, the wedge bonding tool and the surface are raised while extending the spring portion until the cutter makes contact with the surface. In step 712, a second height measurement is determined when the cutter makes contact with the surface (see, for example, the determination of height h2 in Figure 3E). In step 714, the cutter height is determined using the first and second height measurements (for example, by finding the difference between the first and second height measurements).

[0033] Referring to Figure 7B, in step 750, the wire is disengaged from its engagement with the wedge bonding tool. That is, if the wire is engaged with the wedge bonding tool (e.g., under the working end of the wedge bonding tool), the wire is removed from that position. In step 752, the bond head (e.g., mounting the wedge bonding tool and cutter) is moved to the test position (e.g., using its xyz motion system). The test position can be, for example, any desired position on the wedge bonding apparatus. In step 754, the wedge bonding tool is lowered toward the surface integrated with the spring assembly on the wedge bonding apparatus (e.g., see Figure 3G, contact in Figure 3H). In step 756, the spring portion of the spring assembly is compressed by further lowering the wedge bonding tool after contact between the wedge bonding tool and the surface (e.g., see Figure 3I). In step 758, the cutter is lowered toward the wedge bonding tool and the surface until the cutter contacts the surface (e.g., also see Figure 3I). In step 760, a height measurement is determined when the cutter makes contact with the surface (see, for example, height h1 in Figure 3I). This height measurement is used to determine the height of the cutter.

[0034] Referring to Figure 8, in step 800, the wire is disengaged from its engagement with the wedge bonding tool. That is, if the wire is engaged with the wedge bonding tool (e.g., under the working end of the wedge bonding tool), the wire is removed from that position. In step 802, the bond head (e.g., mounting the wedge bonding tool and cutter) is moved to a test position (e.g., using its xyz motion system). The test position can be, for example, any desired position on the wedge bonding apparatus. In step 804, the wedge bonding tool and at least one of the surfaces are moved relative to each other (see the movement of the wedge bonding tool 106 in Figure 2B, or the movement of the surface 104e'''' in Figure 4B). In step 806, a first height measurement is determined when the wedge bonding tool contacts the surface (e.g., see the determination of height h1 in Figure 2C, or the determination of height h1 in Figure 4C). In step 808, at least one of the cutter and the surface is moved relative to each other (see the movement of cutter 108 in Figure 2D, or the movement of surface 104e'''' in Figure 4D). In step 810, a second height measurement is determined when the cutter contacts the surface (see, for example, the determination of height h2 in Figure 2D, or the determination of height h2 in Figure 4D). In step 812, the cutter height is determined using the first and second height measurements (for example, by finding the difference between the first and second height measurements).

[0035] Referring to Figure 9, in step 900, the wire is disengaged from its engagement with the wedge bonding tool. That is, if the wire is engaged with the wedge bonding tool (e.g., under the working end of the wedge bonding tool), the wire is removed from that position. In step 902, the bond head (e.g., mounting the wedge bonding tool and cutter) is moved to a test position (e.g., using its xyz motion system). The test position can be any desired position on the wedge bonding apparatus, for example. In step 904, the cutter height is determined on the wedge bonding apparatus. The cutter height is determined using any technique as desired (e.g., the methods in Figures 2A-2D, 3A-3E, 3F-3I, and 4A-4D). In step 906, the cutting profile is determined using the cutter height determined in step 904. Additional steps can be added. For example, the portion of the wire extending below the wedge bonding tool (see, for example, Figures 5B-5D) can also be used in relation to determining the cutting profile. In such a case, after step 904, the wire is engaged with the wedge bonding tool (e.g., positioned below the working end of the wedge bonding tool) - essentially reversing step 900. The wedge bonding tool (with the wire engaged) is then lowered toward the surface on the wedge bonding apparatus (see, for example, Figure 5C). A height measurement (e.g., the height in Figure 5D) is then determined when the wire contacts the surface - this height measurement provides information about the hwire shown in Figure 5B. Using this information, the process proceeds to step 906, where the cutting profile of the cutter is determined using the cutter height (e.g., at least a first height measurement h1 and a second height measurement h2) and a third height measurement (h2) (wiring). More specifically, the cutter height and the wire can be used to determine the cutting profile.

[0036] As those skilled in the art will understand, various height measurements can be given with respect to a given structure, but these are merely illustrative. For example, Figure 2C shows the height h1 with respect to the tip portion 108a of the cutter 108. Similarly, Figure 2D shows the height h2 with respect to the tip portion 108a of the cutter 108. However, these height measurements (i.e., h1 and h2) can be obtained with respect to various structures, as long as the results determine the cutter height (e.g., RCH shown in Figure 2B).

[0037] As those skilled in the art will understand, the various height measurements described herein (e.g., h1, h2, hwire, etc.) can be determined using various mechanisms. In one example, a z-axis position detector 110d can be used, as shown in Figure 1 (e.g., a z-axis encoder in a z-axis motion system). In another example, the various height measurements described herein can be determined using an overtravel z-axis position detector 110e, as shown in Figure 1 (e.g., an encoder in an overtravel mechanism).

[0038] While various embodiments of the present invention have been shown relating to a wedge bonding tool including a groove (e.g., groove 106b) configured to receive a wire, it is understood that the present invention is applicable to any type of wedge bonding tool (including ribbon bonding tools), whether or not it has a groove.

[0039] While the present 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 can be made in detail within the scope of the claims and equivalents without departing from the invention.

Claims

1. A method for determining the height of the cutter of a wedge bonding apparatus, (a) A step of lowering the wedge bonding tool toward the surface on the wedge bonding apparatus, (b) A step of determining a first height measurement when the wedge bonding tool comes into contact with the surface, (c) A step of lowering the cutter of the wedge bonding apparatus relative to the wedge bonding tool, (d) A step of determining a second height measurement when the cutter comes into contact with the surface, (e) A step of determining the height of the cutter using the first height measurement and the second height measurement, A method of having.

2. A method according to claim 1, wherein the wedge bonding tool and the cutter are carried by a bond head assembly of the wedge bonding apparatus, and the bond head assembly is moved along the Z-axis of the wedge bonding apparatus using a Z-axis motion system.

3. The method according to claim 2, wherein the wedge bonding tool is lowered using the Z-axis motion system in step (a).

4. In the method described in claim 2, A method wherein the cutter is lowered using the Z-axis motion system in step (c).

5. In the method described in claim 2, A method wherein the cutter is lowered in step (c) using a cutter motion system different from the Z-axis motion system.

6. In the method described in claim 2, A method wherein the first height measurement and the second height measurement are each determined using an encoder of the Z-axis motion system.

7. In the method described in claim 2, The bond head assembly includes an overtravel mechanism so that the cutter can be lowered in step (c) after contact with the wedge bonding tool in step (b).

8. In the method described in claim 7, A method wherein the first height measurement is determined using an encoder of the overtravel mechanism.

9. In the method described in claim 7, A method wherein the second height measurement is determined using the encoder of the overtravel mechanism.

10. In the method described in claim 7, A method wherein the first height measurement and the second height measurement are each determined using an encoder of the overtravel mechanism.

11. In the method described in claim 1, A method wherein the height of the cutter is determined by determining the difference between the first height measurement and the second height measurement.

12. In the method described in claim 1, A method wherein the height of the cutter is used for subsequent cutting operations in the wedge bonding apparatus.

13. In the method described in claim 1, The height of the cutter is used in conjunction with the cutter depth value in the wedge bonding apparatus for subsequent cutting operations.

14. In the method described in claim 1, The method is performed in connection with changing from a previous cutter to the current cutter in the wedge bonding apparatus.

15. In the method described in claim 1, The method described above is performed at predetermined intervals.

16. In the method described in claim 1, The method comprising step (b) determining when the wedge bonding tool makes contact with the surface using at least one of a load cell, an electrical conduction connection, and a Z-axis motion system characteristic.

17. In the method described in claim 1, Step (d) is a method for determining when the cutter contacts the surface, using at least one of a load cell, an electrical conductivity connection, and a Z-axis motion system characteristic.

18. A method for determining the height of the cutter of a wedge bonding apparatus, (a) A step of lowering a wedge bonding tool toward a surface on the wedge bonding apparatus, wherein the surface is integrated with a spring assembly. (b) A step of determining a first height measurement when the wedge bonding tool comes into contact with the surface, (c) After the wedge bonding tool and the surface come into contact, the wedge bonding tool is lowered further downward to compress the spring portion of the spring assembly; (d) After step (c), the step of raising the wedge bonding tool and the surface while extending the spring portion until the cutter contacts the surface, (e) A step of determining a second height measurement when the cutter comes into contact with the surface, (f) A step of determining the height of the cutter using the first height measurement and the second height measurement, A method of having.

19. A method according to claim 18, wherein the wedge bonding tool and the cutter are carried by a bond head assembly of the wedge bonding apparatus, and the bond head assembly is moved along the Z-axis of the wedge bonding apparatus using a Z-axis motion system.

20. A method according to claim 19, wherein the wedge bonding tool is lowered using the Z-axis motion system in step (a).

21. A method according to claim 19, wherein the cutter is lowered using the Z-axis motion system in step (c).

22. The method according to claim 19, wherein the cutter is lowered in step (c) using a cutter motion system different from the Z-axis motion system.

23. The method according to claim 19, wherein the first height measurement and the second height measurement are each determined using an encoder of the Z-axis motion system.

24. A method according to claim 19, wherein the bond head assembly includes an overtravel mechanism.

25. A method according to claim 24, wherein the first height measurement is determined using an encoder of the overtravel mechanism.

26. A method according to claim 24, wherein the second height measurement is determined using an encoder of the overtravel mechanism.

27. The method according to claim 24, wherein the first height measurement and the second height measurement are each determined using an encoder of the overtravel mechanism.

28. A method according to claim 18, wherein the height of the cutter is determined by determining the difference between the first height measurement and the second height measurement.

29. A method according to claim 18, wherein the height of the cutter is used for subsequent cutting operations in the wedge bonding apparatus.

30. The method according to claim 18, wherein the cutter height measurement is used in conjunction with the cutter depth value in the wedge bonding apparatus for subsequent cutting operations.

31. A method according to claim 18, wherein the method is performed in connection with changing from a previous cutter to the cutter in the wedge bonding apparatus.

32. A method according to claim 18, wherein the method is performed at predetermined intervals.

33. A method according to claim 18, wherein step (b) includes determining when the wedge bonding tool contacts the surface using at least one of a load cell, an electrical conduction connection, and a Z-axis motion system characteristic.

34. A method according to claim 18, wherein step (3) includes determining when the cutter contacts the surface using at least one of a load cell, an electrical conduction connection, and a Z-axis motion system characteristic.

35. A method for determining the height of the cutter of a wedge bonding apparatus, (a) A step of lowering a wedge bonding tool toward a surface on the wedge bonding apparatus, wherein the surface is integrated with a spring assembly. (b) After contact between the wedge bonding tool and the surface, the step of compressing the spring portion of the spring assembly by further lowering the wedge bonding tool; (c) A step of lowering the cutter relative to the wedge bonding tool and the surface until the cutter contacts the surface, (d) A step of determining the height measurement when the cutter contacts the surface, A method having

36. A method according to claim 35, wherein the wedge bonding tool and the cutter are carried by a bond head assembly of the wedge bonding apparatus, and the bond head assembly is moved along the Z-axis of the wedge bonding apparatus using a Z-axis motion system.

37. A method according to claim 36, wherein the wedge bonding tool is lowered using the Z-axis motion system in step (a).

38. A method according to claim 36, wherein the cutter is lowered using the Z-axis motion system in step (c).

39. The method according to claim 36, wherein the cutter is lowered in step (c) using a cutter motion system different from the Z-axis motion system.

40. In the method described in claim 36, A method wherein the bond head assembly includes an overtravel mechanism.

41. In the method described in claim 40, A method wherein the height measurement is determined using an encoder of the overtravel mechanism.

42. In the method described in claim 35, A method wherein the height measurement is used for subsequent cutting operations in the wedge bonding apparatus.

43. The method according to claim 35, wherein the cutter height measurement is used in conjunction with the cutter depth value in the wedge bonding apparatus for subsequent cutting operations.

44. In the method described in claim 35, The method described above is performed in connection with changing from a previous cutter to the current cutter in the wedge bonding apparatus.

45. A method according to claim 35, wherein the method is performed at predetermined intervals.

46. A method according to claim 35, wherein step (3) includes determining when the cutter contacts the surface using at least one of a load cell, an electrical conduction connection, and a Z-axis motion system characteristic.

47. A method for determining the height of the cutter of a wedge bonding apparatus, (a) A step of moving a wedge bonding tool relative to at least one of the surfaces on the wedge bonding apparatus, (b) A step of determining a first height measurement when the wedge bonding tool comes into contact with the surface, (c) A step of moving the cutter of the wedge bonding apparatus and at least one of the surfaces relative to each other, (d) A step of determining a second height measurement when the cutter comes into contact with the surface, (e) A step of determining the height of the cutter using the first height measurement and the second height measurement, A method of having.

48. A method according to claim 47, wherein the wedge bonding tool and the cutter are carried by a bond head assembly of the wedge bonding apparatus, and the bond head assembly is moved along the Z-axis of the wedge bonding apparatus using a Z-axis motion system.

49. A method according to claim 48, wherein the wedge bonding tool is lowered using the Z-axis motion system in step (a).

50. A method according to claim 48, wherein the surface is raised using a motion system in step (a).

51. A method according to claim 48, wherein the cutter is lowered using the Z-axis motion system in step (c).

52. The method according to claim 48, wherein the cutter is lowered in step (c) using a cutter motion system different from the Z-axis motion system.

53. A method according to claim 48, wherein the surface is raised using a motion system in step (c).

54. The method according to claim 48, wherein the first height measurement and the second height measurement are each determined using an encoder of the Z-axis motion system.

55. A method according to claim 48, wherein the bond head assembly includes an overtravel mechanism so that, after contact of the wedge bonding tool in step (b), the cutter can be moved relative to the surface in step (c).

56. A method according to claim 55, wherein the first height measurement is determined using an encoder of the overtravel mechanism.

57. A method according to claim 55, wherein the second height measurement is determined using an encoder of the overtravel mechanism.

58. The method according to claim 55, wherein the first height measurement and the second height measurement are each determined using an encoder of the overtravel mechanism.

59. A method according to claim 48, wherein the height of the cutter is determined by determining the difference between the first height measurement and the second height measurement.

60. The method according to claim 48, wherein the height of the cutter is used for subsequent cutting operations in the wedge bonding apparatus.

61. The method according to claim 48, wherein the height of the cutter is used in conjunction with the cutter depth value in the wedge bonding apparatus for subsequent cutting operations.

62. A method according to claim 48, wherein the method is performed in connection with changing from a previous cutter to the cutter in the wedge bonding apparatus.

63. A method according to claim 48, wherein the method is performed at predetermined intervals.

64. A method according to claim 48, wherein step (b) includes determining when the wedge bonding tool contacts the surface using at least one of a load cell, an electrical conduction connection, and a Z-axis motion system characteristic.

65. A method according to claim 48, wherein step (d) includes determining when the cutter contacts the surface using at least one of a load cell, an electrical conduction connection, and a Z-axis motion system characteristic.

66. A method for determining the cutting profile of a cutter on a wedge bonding apparatus, (a) A step of determining the height of the cutter of the wedge bonding apparatus, (b) A step of determining the cutting profile of the cutter on the wedge bonding apparatus using the cutter height determined in step (a), The above step (a) is, (a1) A step of lowering the wedge bonding tool toward the surface of the wedge bonding apparatus, (a2) A step of determining a first height measurement when the wedge bonding tool comes into contact with the surface, (a3) A step of lowering the cutter of the wedge bonding apparatus relative to the wedge bonding tool, (a4) A step of determining a second height measurement when the cutter comes into contact with the surface, (a5) A step of determining the height of the cutter using the first height measurement and the second height measurement, A method that includes [something].

67. A method for determining the cutting profile of a cutter on a wedge bonding apparatus, (a) A step of determining the height of the cutter of the wedge bonding apparatus, (b) A step of determining the cutting profile of the cutter on the wedge bonding apparatus using the cutter height determined in step (a), The above step (a) is, (a1) A step of moving a wedge bonding tool toward a surface on the wedge bonding apparatus, wherein the surface is integrated with a spring assembly, (a2) A step of determining a first height measurement when the wedge bonding tool comes into contact with the surface, (a3) After contact between the wedge bonding tool and the surface, the step of compressing the spring portion of the spring assembly by further lowering the wedge bonding tool; (a4) After step (a3), the step of raising the wedge bonding tool and the surface while extending the spring portion until the cutter contacts the surface, (a5) A step of determining a second height measurement when the cutter comes into contact with the surface, (a6) A method comprising the step of determining the height of a cutter using the first height measurement and the second height measurement.

68. A method for determining the cutting profile of a cutter on a wedge bonding apparatus, (a) A step of determining the height of the cutter of the wedge bonding apparatus, (b) A step of determining the cutting profile of the cutter on the wedge bonding apparatus using the cutter height determined in step (a), The above step (a) is, (a1) A step of moving at least one of the wedge bonding tool and the surface on the wedge bonding apparatus relative to each other, (a2) A step of determining a first height measurement when the wedge bonding tool comes into contact with the surface, (a3) A step of moving at least one of the cutter of the wedge bonding apparatus and the surface relative to each other, (a4) A step of determining a second height measurement when the cutter comes into contact with the surface, (a5) A step of determining the height of the cutter using the first height measurement and the second height measurement, A method that includes [something].

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