Ultrasonic transducers, including wire bonding machines for ultrasonic transducers, and related methods.

Abstract

An ultrasonic transducer is provided. The ultrasonic transducer system includes a transducer body, wherein at least a portion of the surface of the transducer body includes a processed region. The processed region has a modified state portion located on the surface of the transducer body.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 180,480, filed on April 27, 2021, the contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to an ultrasonic transducer, and more particularly to an improved ultrasonic transducer, as well as to a wire bonding machine and related methods including the ultrasonic transducer. Background Technology

[0004] Ultrasonic transducers have many applications. For example, they are widely used in semiconductor packaging equipment, such as automated wire bonding machines (e.g., ball bonding machines, wedge bonding machines, strip bonding machines, etc.) and advanced packaging machines (e.g., flip chip bonding machines, such as thermoforming machines, etc.).

[0005] Regarding wire bonding machines, ultrasonic transducers are typically used to form bonding wires. A wire bonding tool is attached to the transducer. The transducer generally includes an actuator, such as a stacked piezoelectric element (e.g., a piezoelectric crystal, piezoelectric ceramic, etc.). Electrical energy is applied to the actuator, and this electrical energy is converted into mechanical energy, thereby driving the end of the wire bonding tool to form a bond through a rubbing motion.

[0006] US Patent Nos. 5,595,328 (titled "Self-isolation Ultrasonic Transducer"); 5,699,953 (titled "Multi Resonance Unibody Ultrasonic Transducer"); 5,884,834 (titled "Multi-Frequency Ultrasonic Wire Bonder and Method"); 7,137,543 (titled "Integrated Flexure Mount Scheme for Dynamic ISOLATION of Ultrasonic Transducers"); 8,251,275 (titled "Ultrasonic Transducers for Wire Bonding and Methods of Forming Wire Bondes Using Ultrasonic Transducers"); 9,136,240 (titled "Systems and Methods for Bonding"). SEMICONDUCTOR ELEMENTS”; and 10,381,321 (titled “ULTRASONIC TRANSDUCER SYSTEMS INCLUDING TUNED RESONATORS, EQUIPMENTINCLUDING SUCH SYSTEMS, AND METHODS OF PROVIDING THE SAME”) relate to ultrasonic transducers and are incorporated herein by reference in their entirety.

[0007] Traditional ultrasonic transducers, including those used in wire bonding technology, suffer from many shortcomings. Therefore, it is desirable to provide improved ultrasonic transducers, wire bonding machines, and related methods. Summary of the Invention

[0008] According to an exemplary embodiment of the present invention, an ultrasonic transducer is provided. The ultrasonic transducer includes a transducer body, wherein at least a portion of the surface of the transducer body includes a processed region. The processed region has a modified state portion located on the surface of the transducer body.

[0009] According to another exemplary embodiment of the present invention, a wire bonding machine is provided. The wire bonding machine includes a bonding head assembly and an ultrasonic transducer carried by the assembly. The ultrasonic transducer includes a transducer body, wherein at least a portion of the surface of the transducer body includes a processed area. The processed area has a modified state portion located on the surface of the transducer body.

[0010] According to another exemplary embodiment of the present invention, a method for providing an ultrasonic transducer is provided. The method includes the steps of: (a) providing a transducer body; and (b) processing at least a portion of the surface of the transducer body to create a processed region having a modified state portion located on the surface of the transducer body. Attached Figure Description

[0011] The invention can be best understood by reading the following detailed description in conjunction with the accompanying drawings. It should be emphasized that, by convention, the various features in the figures are not drawn to scale. Instead, for clarity, the dimensions of the various features have been arbitrarily enlarged or reduced. The illustrations include the following figures:

[0012] Figure 1A This is a side cross-sectional block diagram of a wire bonding machine according to an exemplary embodiment of the present invention;

[0013] Figure 1B A perspective view of an ultrasonic transducer according to an exemplary embodiment of the present invention;

[0014] Figure 1C for Figure 1B A partial perspective view of the ultrasonic transducer shown;

[0015] Figures 2A-2B , Figures 3A-3B as well as Figures 4A-4B Top view block diagram and corresponding partial cross-sectional side view of various ultrasonic transducers according to various exemplary embodiments of the present invention;

[0016] Figures 5A-5C Flowcharts illustrating different methods for providing an ultrasonic transducer system according to various exemplary embodiments of the present invention. Detailed Implementation

[0017] According to various exemplary embodiments of the invention, areas of the ultrasonic transducer (e.g., a titanium alloy transducer) are processed (e.g., coated) to reduce static and / or dynamic relative sliding wear between (i) the integrated tool holder of the ultrasonic transducer and (ii) the working tool (e.g., a wire bonding machine).

[0018] For example, to reduce wear between the integrated tool holder and the working tool (e.g., a replaceable wire bonding tool) of an ultrasonic transducer, at least a portion of the surface of the ultrasonic transducer is processed (e.g., coated) to reduce friction (e.g., reduce burrs) and / or increase surface hardness, and to extend the service life of the ultrasonic transducer.

[0019] For example, the coating on the surface of the ultrasonic transducer can be a thin and durable transition layer (e.g., between 1 μm and 5 μm thick) located between (i) the ultrasonic transducer body and (ii) the working tool. The ultrasonic transducer body can be formed of a relatively soft material (e.g., titanium), which is more prone to burrs, wherein the hardness of such material can be on the order of HRC 36. The working tool, for example, can be formed of a relatively hard material (e.g., alumina, zirconia-toughened alumina, etc.), whose hardness can be on the order of HRC 90.

[0020] In an exemplary embodiment of the invention, a coating is applied to the surface of an ultrasonic transducer to act as a burr suppressor, reducing wear primarily by reducing friction. In various exemplary embodiments of the invention, a coating is applied to the surface of an ultrasonic transducer to act as a surface hardness enhancer, and wear reduction can be achieved by the relative hardness ratio between the coating and the tool (e.g., the harder the coating, the less wear).

[0021] In embodiments where the applied coating hardness exceeds the working tool hardness (e.g., the coating hardness is greater than the hardness of alumina HRC 90), inexpensive, replaceable working tools (e.g., wire bonding tools) may tend to be worn parts rather than expensive ultrasonic transducers (e.g., titanium alloy ultrasonic transducers), thus greatly improving transducer performance and service life.

[0022] Exemplary coatings that can be applied to at least a portion of the surface of the transducer body of an ultrasonic transducer include at least one of the following: titanium nitride (TiN), diamond-like carbon (DLC), bright chromium, tungsten disulfide, titanium aluminum nitride, and composite diamond coating (CDC). Exemplary thicknesses of such applied coatings may be between 1 μm and 5 μm, between 1 μm and 10 μm, and so on. The specific choice of coating may be based at least in part on, for example, its adhesion to the transducer body material.

[0023] According to the present invention, the processed area of ​​the transducer body (e.g., the coating area on the surface of the transducer body) can be modified during processing. For example, in applications where a coating is applied to the transducer body, the coating can be machined or otherwise desired to perform a specific function (e.g., to maintain desired tolerances, etc.).

[0024] According to various exemplary embodiments of the present invention, an ultrasonic transducer is provided comprising a transducer body. At least a portion of the surface of the transducer body includes a machined region. The machined region has a modified state portion (e.g., wherein the modified state portion may be configured to reduce burrs and / or reduce wear located in the machined region). The machined region may include an outer surface of the transducer body (e.g., the entire outer surface or substantially the entire outer surface). However, the machined region may also include specific target regions of the surface, such as, for example: a region of the transducer body defining a hole configured to receive a wire bonding tool, and a region of the transducer body defining another hole (sometimes referred to herein as a second hole, the second hole being configured to receive a retainer for securing the aforementioned hole during engagement with the wire bonding tool).

[0025] As described above, the modified state portion may include a coating applied to the processed area. Another embodiment of the modified state portion includes a passivation state portion at the processed area (e.g., where the passivation state portion includes an anodized state portion). Other embodiments of the modified state portion are contemplated.

[0026] According to a particular exemplary aspect of the invention, the processed area (i) has a coefficient of friction of less than 0.2 and / or (ii) has a hardness of greater than 90 HRC.

[0027] Please refer to the diagram below. Figures 1A-1C The wire bonding machine and the ultrasonic transducer are illustrated, which is helpful in explaining various exemplary embodiments of the invention. For example, Figures 1A-1C The ultrasonic transducer 100 shown may include a processed area having a state-altered portion located on the surface of the transducer body (e.g., see...). Figures 2A-2B , Figures 3A-3B as well as Figures 4A-4B (Exemplary processed area shown)

[0028] like Figure 1A As shown, the wire bonding machine 150 includes a bonding head assembly 162 and an ultrasonic transducer 100 carried by the bonding head assembly 162. The ultrasonic transducer 100 includes a transducer body (e.g., see...). Figure 1B Transducer body 100'), wherein at least a portion of the surface of the transducer body includes a processed area (e.g., see...). Figures 2A-2B , Figures 3A-3B as well as Figures 4A-4B The processed area has a modified state section located on the surface of the transducer body.

[0029] The ultrasonic transducer 100, carrying a wire bonding tool 108, bonds the lead portion (of the lead 160) to the workpiece 156. Figure 1AIn the illustrated embodiment, workpiece 156 includes a semiconductor die 158 mounted on a substrate 154. Workpiece 156 is supported by a support structure 152 of a wire bonding machine 150. Those skilled in the art will understand that the wire bonding tool 108 (carried by a bonding head assembly 162) is movable along multiple axes of the wire bonding machine 150 to perform wire bonding operations. For example, the wire bonding tool 108 is moved along the x and y axes of the wire bonding machine 150 by movement of the bonding head assembly 162, and along the z-axis of the wire bonding machine 150 by a z-axis motion system (not shown).

[0030] The ultrasonic transducer 100 provides ultrasonic abrasion at the working end 108a (also referred to as the tip portion of the wire bonding tool 108) of the wire bonding tool 108 to bond a portion of the lead wire 160 to the workpiece 156. Figure 1A In this configuration, the airless bulb 160a (e.g., a portion of the lead wire 160) is located at the working end 108a of the wire bonding tool 108. Through a wire bonding operation, the airless bulb 160a will be bonded to the workpiece 156.

[0031] Figures 1B-1C It is a display Figure 1A A perspective view showing more details of an example ultrasonic transducer. The ultrasonic transducer 100 includes a transducer body 100'. The transducer body 100' includes mounting structures 102a, 102b for mounting the ultrasonic transducer 100 to a bonding head assembly of a wire bonding machine (e.g., see...). Figure 1A (Middle bonding head assembly 162). Piezoelectric crystal 104 is provided in cavity 116 defined by ultrasonic transducer 100 (where cavity 116 is as follows). Figures 2A-2B , Figures 3A-3B as well as Figures 4A-4B As shown, within the ultrasonic transducer 100, the piezoelectric crystal 104 provides ultrasonic energy to the ultrasonic transducer 100 by applying electrical energy to electrodes 106a and 106b. This ultrasonic energy is then conducted to the wire bonding tool 108 used in the wire bonding operation.

[0032] The transducer body 100' defines a hole 112 configured to receive a wire bonding tool 108. The transducer body 100' also defines a second hole 110a configured to receive a retainer 110 for securing the hole 112 during engagement with the wire bonding tool 108. For example, the retainer 110 may be a screw or other threaded fastener and configured to engage the threads 110a1 of the second hole 110a. That is, using an integrated tool holder 114 (e.g., a clamping fixture), the retainer 110 engages in the second hole 110a, securing the wire bonding tool 108 in the hole 112. More specifically, when the retainer 110 is screwed into the second hole 110a, the integrated tool holder 114 is pressed, causing the hole 112 to contract. When the hole 112 contracts, the support surface 112a moves radially inward, thereby securing the wire bonding tool 108 in the hole 112.

[0033] Figures 1A-1C Exemplary features of a wire bonding machine 150 including an ultrasonic transducer 100 are shown. It should be understood that these different features may be varied within the scope of the invention. An exemplary feature according to an aspect of the invention is that at least a portion of the surface of the transducer body includes a processed area. This processed area has a modified state portion (e.g., wherein the modified state portion may be configured to reduce burrs and / or wear located in the processed area). Figures 2A-2B , Figures 3A-3B as well as Figures 4A-4B Various examples of ultrasonic transducers 100 with different processed regions having altered states are shown (in... Figure 2A The middle part is labeled as ultrasonic transducer 100a. Figure 3A The middle is 100b. Figure 4A (The value is 100c). Of course, this invention is not limited to... Figures 2A-2B , Figures 3A-3B as well as Figures 4A-4B The example shown.

[0034] For reference Figure 2A Ultrasonic transducer 100a ( Figures 1A-1C An example of the transducer 100 shown includes a transducer body 100a'. The transducer body 100a' defines a bore 112, a second bore 110a, a cavity 116, and an integrated tool holder 114. An example fastener 102' is shown for engagement with each mounting structure 102a, 102b for mounting the ultrasonic transducer 100a to a bonding head assembly. The transducer body 100a' includes a surface 100a1 (i.e., an outer surface). As provided above, at least a portion of surface 100a1 includes a machined area. Figure 2A In the example shown, the processed area is region 100a2 that defines the hole 112 configured to receive a wire bonding tool. Figure 2BThe cross section in the AA direction is shown, which is the cross section of region 100a2.

[0035] For reference Figure 3A Ultrasonic transducer 100b ( Figures 1A-1C Another example of the transducer 100 shown includes a transducer body 100b'. The transducer body 100b' defines a bore 112, a second bore 110a, a cavity 116, and an integrated tool holder 114. An example fastener 102' is shown for engagement with each mounting structure 102a, 102b for mounting the ultrasonic transducer 100b to a bonding head assembly. The transducer body 100b' includes a surface 100b1 (i.e., the outer surface). As provided above, at least a portion of surface 100b1 includes a machined area. Figure 3A In the example shown, the processed area includes (i) a region 100b2 defining a hole 112 configured to receive a wire bonding tool and (ii) a region 100b3 defining another hole 110a (sometimes referred to herein as a second hole, the second hole being configured to receive a retainer 110 for securing the hole 112 during engagement with the wire bonding tool). Figure 3B The cross section in the BB direction is shown, which is the cross section of region 100b2.

[0036] For reference Figure 4A 100c ultrasonic transducer Figures 1A-1C Another example of the transducer 100 shown includes a transducer body 100c'. The transducer body 100c' defines a bore 112, a second bore 110a, a cavity 116, and an integrated tool holder 114. An example fastener 102' is shown for engagement with each mounting structure 102a, 102b for mounting the ultrasonic transducer 100c to a bonding head assembly. The transducer body 100c' includes a surface 100c1 (i.e., an outer surface). As provided above, at least a portion of the surface 100c1 includes a machined area. Figure 4A In the example shown, the processed area includes the outer surface of the transducer body 100c and the processed area 100c2. Figure 4A The processed area 100c2 further includes (i) a region 100c3 defining a hole 112 configured to receive a wire bonding tool, and (ii) a region 100c4 defining another hole 110a (sometimes referred to herein as a second hole, the second hole being configured to receive a retainer 110 for securing the hole 112 during engagement with the wire bonding tool). Figure 4B The cross section in the CC direction is shown, which is the cross section of region 100c3.

[0037] As described above, the processed area includes the altered state portion located on the surface of the transducer body. This applies to any processed area according to any embodiment of the invention. For example, in Figures 2A-2B The processed area 100a2 shown, or Figures 3A-3B The processed areas 100b2 and 100b3 shown are, or Figures 4A-4B The processed area 100c2 shown includes a modified state portion located on the surface of the transducer body. For example, the modified state portion may be configured to reduce wear and / or burrs in the transducer body area defining the aforementioned hole 112.

[0038] The altered state may include a coating applied to the processed area. Examples of coating materials include at least one of the following: titanium nitride, diamond-like carbon, bright chromium, tungsten disulfide, aluminum titanium nitride, and composite diamond coatings. Exemplary ranges for coating thickness include (i) between 1 μm and 10 μm, and between 1 μm and 5 μm.

[0039] The altered state may include a passivated state (e.g., an anodized state) in the processed area.

[0040] Figures 5A-5C A flowchart illustrating an exemplary method for providing an ultrasonic transducer according to the present invention is provided. As will be understood by those skilled in the art, certain steps included in the flowchart may be omitted; certain additional steps may be added; and the order of the steps may be changed relative to the order shown—all within the scope of the present invention.

[0041] For reference Figure 5A In step 500, a transducer body is provided. In step 502, at least a portion of the surface of the transducer body is processed to create a processed region. The processed region has a modified state portion located on the surface of the transducer body.

[0042] For reference Figure 5B At step 510, a transducer body is provided. At step 512, at least a portion of the surface of the transducer body is coated to create a coating area (i.e., in this example, the processed area is the coating area). The coating can be applied using any of the following processes: spraying, plasma vapor deposition (PVD), chemical vapor deposition (CVD), etc. If the coating is not applied to the entire outer surface of the transducer body, a masking method (or other selective coating process) can be used.

[0043] For reference Figure 5CIn step 520, a transducer body is provided. In step 522, at least a portion of the surface of the transducer body is processed to create a processed area. The processed area has a passivated state portion (e.g., an anodized state portion) located on the surface of the transducer body. For example, an electrolytic reaction can be performed at the surface to provide the passivated state portion. Such a passivated state portion can be, for example, providing a protective oxide film at the surface; increasing the thickness of the natural oxide film at the surface; or generating a chemical reaction by consuming a small portion of the material at the surface, etc.

[0044] While the present invention is primarily described as relating to ultrasonic transducers used in wire bonding machines, it is not limited thereto. The teachings of the present invention are applicable to a wide range of applications of ultrasonic transducers beyond wire bonding, including other applications in the semiconductor industry (e.g., flip chip bonding, wafer-level bonding, etc.), and applications beyond the semiconductor industry. Furthermore, the working tools carried by the ultrasonic transducer are not limited to wire bonding tools; other types of working tools are envisioned.

[0045] Although the invention has been illustrated and described herein with reference to specific embodiments, it is not intended to be limited to the details shown. Various modifications may be made without departing from the invention and within the scope and limitations of the claims and their equivalents.

Claims

1. An ultrasonic transducer, comprising: The transducer body has at least a portion of its surface including a processed area having a modified state portion located on the surface of the transducer body. The transducer body defines a hole configured to receive a wire bonding tool, and the machined area includes the region of the transducer body defining the hole. The processed area has been processed to reduce friction with the wire bonding tool.

2. The ultrasonic transducer according to claim 1, wherein, The transducer body defines a second hole configured to receive a retainer for securing the hole during engagement with a wire bonding tool. The machined area includes the region of the transducer body defining the second hole.

3. The ultrasonic transducer according to claim 1, wherein, The modified state is configured to reduce wear in the area of ​​the transducer body that defines the aperture.

4. The ultrasonic transducer according to claim 1, wherein, The modified state section is configured to reduce burrs located in the area of ​​the transducer body defining the aperture.

5. The ultrasonic transducer according to claim 1, wherein, The processed area includes the outer surface of the transducer body.

6. The ultrasonic transducer according to claim 1, wherein, The altered state includes the coating applied to the processed area.

7. The ultrasonic transducer according to claim 6, wherein, The coating has a thickness between 1 µm and 10 µm.

8. The ultrasonic transducer according to claim 6, wherein, The coating includes at least one of the following: titanium nitride, diamond-like carbon, bright chromium, tungsten disulfide, aluminum titanium nitride, and composite diamond coating.

9. The ultrasonic transducer according to claim 1, wherein, The altered state includes the passivated state of the processed area.

10. The ultrasonic transducer according to claim 9, wherein, The passivated state includes the anodized state.

11. The ultrasonic transducer according to claim 1, wherein, The hardness of the processed area is greater than 90 HRC.

12. The ultrasonic transducer according to claim 1, wherein, The coefficient of friction of the processed area is less than 0.

2.

13. The ultrasonic transducer according to claim 1, wherein, The altered state part includes a coating applied to the processed area, the coating thickness being between 1 µm and 5 µm.

14. The ultrasonic transducer according to claim 13, wherein, The coating includes at least one of the following: titanium nitride, diamond-like carbon, bright chromium, tungsten disulfide, aluminum titanium nitride, and composite diamond coating.

15. A wire bonding machine, comprising: Bonding head assembly; as well as An ultrasonic transducer carried by a bonding head assembly, the ultrasonic transducer comprising: a transducer body, at least a portion of the surface of the transducer body including a processed region, the processed region having a modified state portion located on the surface of the transducer body. The transducer body defines a hole configured to receive a wire bonding tool, and the machined area includes the region of the transducer body defining the hole. The processed area has been processed to reduce friction with the wire bonding tool.

16. The wire bonding machine according to claim 15, wherein, The transducer body defines a second hole configured to receive a retainer for securing the hole during engagement with a wire bonding tool. The machined area includes the region of the transducer body defining the second hole.

17. The wire bonding machine according to claim 15, wherein, The altered state includes the coating applied to the processed area.

18. The wire bonding machine according to claim 15, wherein, The altered state section includes the passivation state section located in the processed area.

19. The wire bonding machine according to claim 15, wherein, The altered state part includes a coating applied to the processed area, the coating thickness being between 1 µm and 5 µm.

20. The wire bonding machine according to claim 19, wherein, The coating includes at least one of the following: titanium nitride, diamond-like carbon, bright chromium, tungsten disulfide, aluminum titanium nitride, and composite diamond coating.

21. A method for providing an ultrasonic transducer, the method comprising the steps of: (a) Providing a transducer body; and (b) Processing at least a portion of the surface of the transducer body to create a processed region, the processed region having a modified state portion located on the surface of the transducer body. In step (a), the transducer body provided defines a hole configured to receive a wire bonding tool, and step (b) causes the machined area to include the area of ​​the transducer body defining the hole. The processed area has been processed to reduce friction with the wire bonding tool.

22. The method according to claim 21, wherein, The transducer body provided in step (a) defines a second hole configured to receive a retainer for securing the hole during engagement with a wire bonding tool, and step (b) results in the machined area including the region of the transducer body defining the second hole.

23. The method according to claim 21, wherein, Step (b) results in the altered state of the part including the coating applied to the processed area.

24. The method according to claim 21, wherein, Step (b) results in the altered state including the passivated state located in the processed area.

25. The method according to claim 21, wherein, The altered state part includes a coating applied to the processed area, the coating thickness being between 1 µm and 10 µm.

26. The method of claim 25, wherein, The coating includes at least one of the following: titanium nitride, diamond-like carbon, bright chromium, tungsten disulfide, aluminum titanium nitride, and composite diamond coating.

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