Self-aligning tip

Abstract

A die placement system provides a tip body and a die placement head to ensure planarity of a die to a substrate without the need for calibration before each pick and place operation. A self-aligning tip incorporated into the tip body aids in die placement / attachment. This tip provides a global correction for planarity errors that exist between the die and the substrate, whether these errors are due to gantry misalignment (i.e., die side misalignment) or machine deck tool misalignment (i.e., substrate side misalignment).

Description

[0001] Related Applications

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 070,873, filed August 27, 2020, the full text of which is incorporated herein by reference. Technical Field

[0003] This invention relates to microelectronic packaging, and more particularly, to systems and methods for ensuring the flatness of a die to a substrate when attaching a die to a substrate. Background Technology

[0004] Integrated circuit (IC) manufacturing typically involves forming tiny solid-state devices and circuits within a semiconductor wafer using complex photolithography processes. These processes generally include forming material layers on the wafer, patterning the layers, doping the substrate and / or the patterned layers, and thermally treating (e.g., annealing) the resulting structure. These processes are then repeated to build the IC structure. The result is a wafer containing a large number of ICs.

[0005] After wafer fabrication, it typically undergoes a sorting process. Sorting involves electrically testing the functionality of each IC chip on the wafer. After sorting, the wafer is separated into individual IC chips, which are then individually or in groups packaged and incorporated into a substrate, such as a printed circuit board (PCB). At this stage of the process, the individual ICs are typically referred to as dies. These dies must then be placed on the substrate and secured to specific locations on the substrate, thus becoming electrically and / or optically connected to other components designed to interact with them.

[0006] In its broadest sense, die bonding processes can be based on epoxy resin or eutectic bonding. In epoxy die bonding, the die is typically placed on epoxy resin at room temperature. It is then later reflowed in an oven to 'cure' the epoxy resin and freeze the die in place. For some epoxy applications that use UV-cured epoxy resin, curing is performed in situ using targeted UV light to freeze / cur the die and prevent it from shifting after placement. In situ bonding typically implies that the die bond holds the die in place during curing. For epoxy processes, especially for larger die sizes, die-substrate flatness is important for maintaining a uniform epoxy bond thickness under the die.

[0007] In eutectic die bonding processes, the die is typically reflowed in situ. Solder may be pre-deposited on the back of the die or substrate. A die with solder bumps is an example of pre-deposited solder on the die. In some cases, solder may be pre-deposited on the entire bottom surface of the die. In others, a solder preform is used. First, a preform (typically <25µm thick) is placed and the die is placed on top of the preform. Then, heat is applied to reflow the die as the bonding head holds the die in place.

[0008] For high-power applications, pre-deposited solder or preforms are typically not used. For these applications, the gold-silicon (Au-Si) interface is created by wiping the die at temperatures >400°C. At these high temperatures, silicon diffuses into the gold; the wiping motion minimizes voids or cavitation in the Au-Si interface. Voids cause hot spots on the die when it is powered on, leading to failure. For these applications, the die is thinned (50µm or less) for more efficient heat dissipation. In such applications, (when wiping the die to the substrate), if the contact is not planar, Au-Si diffusion occurs only at the contact point / region, potentially causing die failure when wire bonding is applied in subsequent processes or when the die is powered on.

[0009] Thermocompression bonding is a common method for attaching a die to a substrate. While the term "thermocompression bonding" typically refers to a specific die attachment process with particular properties, often involving relatively high forces (i.e., >>1 kg), and most commonly used (where the die has thousands of solder bumps requiring minimal force (in grams per bump) to flatten and contact the underlying substrate before heating to reflow temperature), the term is also used more broadly herein to refer to the die attachment process. The flatness between the bonding head and the substrate is crucial for this process and for ensuring that all bumps contact their corresponding bonding pads underneath and for uniform reflow without attaching / bridging to their adjacent bumps.

[0010] The machine responsible for placing dies onto a substrate is called a die placement system, thermo-bonding system, and sometimes "die bonder." Placing a die onto a substrate or printed circuit board is commonly referred to in the industry as die placement, die attachment, or die bonding operation. During die placement operations, die positioning must be highly precise and accurate to ensure proper interconnection between the die and the substrate.

[0011] While these technologies have served the industry well for many years, existing die bonding systems and methods have failed to achieve satisfactory bonding performance and yield when bonding recent generations of dies to substrates. These newer generations of dies and substrates utilize an increased number of connections, solder bumps, or other methods between the die and substrate, typically without requiring a corresponding increase in die or substrate size. To allow dies of similar size to accommodate these additional connections, each connection has become smaller, and placement accuracy (including planarity) has become more critical. For example, in newer photonic packaging designs, the pre-deposited solder layer is extremely thin. Therefore, die-to-substrate planarity needs to be controlled to a higher degree than ever before to ensure uniform reflow of all solder pads on the die.

[0012] Furthermore, dies can vary significantly in size, thickness, and flatness, but must still be placed using a uniformly distributed, consistent, precise, and accurate force. For example, when placing dies onto epoxy resin, it is crucial that the epoxy bond line thickness guidelines are met after placement. When placing extremely thin dies (i.e., 50µm or less) in a eutectic attachment process, excessive impact force can cause the die to break. The error tolerance for such placement operations is quite small, and even if the average force is within acceptable limits, the ever-present flatness error between the die and the substrate can still lead to high localized forces causing failure. Unfortunately, current methods for ensuring flatness often result in slow cycle times due to the need to recalibrate each die or the use of single calibrations that cannot account for variations between dies that lead to misalignment.

[0013] For example, one currently available solution involves using a tip mounted to the gimbal, which may be referred to as a gimbal tip. While this helps ensure flatness, this solution does not prevent die wiping because the axis of rotation is not at the bottom of the die, resulting in relative movement between the die and the substrate during placement, which can damage these fragile structures. Furthermore, current designs require a minimum force (typically >30 grams) to force the gimbal to self-level, which can damage the die / substrate and / or limit placement accuracy.

[0014] Furthermore, in many cases, the challenge of such operations is increased by the need for the die placement system to place multiple dies, which are often different from each other, onto a single substrate. Because different types of dies are not uniform in size or shape, the die placement head (also referred to herein as the tip body, the part of the die placement system that contacts the die itself and is typically ultimately responsible for its precise placement (in some machines, the substrate θ orientation is adjustable) is specific to each type of die to be placed. In such cases, the die placement head must be exchanged during a die placement operation with a die placement head corresponding to the next die type to be placed before the next die placement operation can continue.

[0015] This exchange of die placement heads can be manual or automatic. Manual methods require a human operator to open the machine and subsequently exchange the die placement head, while automatic exchange is typically accomplished by moving the die placement head to the tool carrier and replacing it with the die placement head corresponding to the next die to be placed. Both manual and automatic die placement head exchanges slow down the die placement process, and manual exchanges also pose a significant risk of contamination because the system must be opened for the exchange operation. While automatic die placement head exchanges are faster than manual exchanges, they still require the die placement head to travel a significant distance within the system, potentially leading to a loss of placement accuracy due to tracking issues (such as drift) and increased cycle time due to the time spent traversing this distance.

[0016] Today, with a wide range of high-density die package designs available and more being developed daily, the demands on die placement systems are increasing. Modern dies require die bonding equipment that offers precision, versatility, and speed beyond what is currently available for maximizing productivity, while minimizing defects caused by incorrect die placement. This is particularly significant given that the manufacturing process now involves creating and testing dies. Future generations of dies are likely to place even higher demands on die placement equipment.

[0017] Therefore, there is a need for techniques to improve the accuracy, precision, and consistency of die placement and the application of die placement forces by ensuring the flatness between the die and the substrate and minimizing the forces required to flatten the die and the substrate, while minimizing scrubbing and accelerating the die placement process (including cases where multiple dies must be placed on a single substrate). Summary of the Invention

[0018] A novel tip body ensures die-to-substrate flatness without requiring calibration prior to each pick-and-place operation. In different configurations, the same tip body provides full angular compliance between the die and substrate during bonding operations, allowing for strong and accurate bonding even when both are significantly non-planar.

[0019] The embodiments also utilize a die head mounting turntable to accelerate cycle time and reduce the risk of contamination associated with repeatedly opening the die bonding system to manually replace the tip.

[0020] One embodiment of this disclosure provides a self-aligning tip system comprising: a tip holder including a threaded section disposed on its distal end and a hollow cavity; a lockable swivel disposed in the hollow cavity of the tip holder, the lockable swivel including a central bore configured to retain the tip; and a locking cap including a central bore configured to allow the tip to pass through therethrough, wherein the locking cap is configured to screw onto the threaded section of the tip holder and to retain the lockable swivel within the cavity of the tip holder, wherein when the locking cap is loosely installed, the tip held in the lockable swivel is allowed to roll, pitch, and yaw while maintaining accurate θ-alignment, and wherein when the locking cap is securely installed, the tip held in the lockable swivel is locked in terms of roll, pitch, and yaw.

[0021] Another embodiment of this disclosure provides this self-aligned tip system, wherein the tip holder includes an upper segment configured to be held in a die bonding system.

[0022] Another embodiment of this disclosure provides this self-aligning tip system, wherein the lockable swivel includes a swivel profile on its top and bottom sides, and wherein the tip holder and locking cap include corresponding swivel profiles on their bottom and top sides, respectively.

[0023] Another embodiment of this disclosure provides this self-aligning tip system, which further includes a spring disposed between the lockable swivel and the locking cap.

[0024] Another embodiment of this disclosure provides this self-aligning tip system, wherein the locking cap and lockable swivel include a spring seat configured to position the spring.

[0025] Another embodiment of this disclosure provides this self-aligned tip system, wherein the spring is configured to bias the tip held in the lockable swivel to a neutral position.

[0026] Another embodiment of this disclosure provides this self-aligned tip system, which further includes a magnet disposed in the tip holder.

[0027] Another embodiment of this disclosure provides this self-aligned tip system, wherein the magnet is configured to bias the tip held in the lockable swivel to a neutral position.

[0028] Another embodiment of this disclosure provides this self-aligned tip system, which further includes a magnet disposed in the tip holder.

[0029] Another embodiment of this disclosure provides this self-aligned tip system, wherein the magnet is configured to bias the tip held in the lockable swivel to a neutral position.

[0030] Another embodiment of this disclosure provides this self-aligning tip system, wherein the self-aligning tip system is configured such that tip alignment occurs at a rotational center located at the bottom of the bare die held by the tip by the lockable swivel.

[0031] Another embodiment of this disclosure provides this self-aligned tip system, which further includes at least one vent disposed in the tip holder.

[0032] Another embodiment of this disclosure provides this self-aligned tip system, wherein the self-aligned tip system is configured to lock the tip in place using a vacuum.

[0033] Another embodiment of this disclosure provides this self-aligned tip system, which further includes a tip held in the lockable swivel, wherein the tip includes at least one vent configured to allow positive pressure and / or vacuum to be transferred from the back side of the tip to its distal end, the distal end being configured to mount a die to a substrate.

[0034] Another embodiment of this disclosure provides this self-aligning tip system, wherein when the tip is in an unlocked position, the tip is configured to reduce friction associated with tip alignment by utilizing a sudden or steady airflow through the at least one vent disposed therein.

[0035] Another embodiment of this disclosure provides this self-aligning tip system, wherein the lockable swivel utilizes a clamp retaining system to hold the tip.

[0036] Another embodiment of this disclosure provides this self-aligning tip system, wherein the locking cap further includes a preloaded locking tab configured to prevent the lockable swivel from rotating relative to the self-aligning tip system after tightening.

[0037] One embodiment of this disclosure provides a method for planarizing a tip with a substrate, the method comprising: using a self-aligned tip system described herein: holding the tip within the lockable swivel; releasing the locking cap to allow the tip to roll, pitch, and yaw while maintaining accurate θ-registration; bringing the tip into contact with the substrate; and tightening the locking cap to lock the roll, pitch, and yaw of the tip.

[0038] One embodiment of this disclosure provides a die bonding system comprising: a turntable including a rotation measuring device and a plurality of self-aligned tip system holding portions positioned substantially adjacent to its periphery, wherein each self-aligned tip system holding portion includes two concentric holes: a first hole and a second hole, the first hole extending completely through the turntable and the second hole positioned on a side of the turntable opposite to and concentric with the first hole, wherein the second hole extends only partially into the turntable, and wherein, upon rotation, each of the plurality of self-aligned tip system holding holes is alignable with a tool; and a motor configured to rotate the turntable upon activation, wherein at least one of the plurality of self-aligned tip system holding portions includes a self-aligned tip system.

[0039] One embodiment of this disclosure provides a self-aligning tip system comprising: a tip holder including at least one vent, a threaded section disposed at its distal end, and a hollow cavity; a lockable swivel including a central bore configured to retain the tip; a locking cap disposed within the hollow cavity of the tip holder, the lockable swivel including a central bore configured to allow the tip to pass through therethrough, wherein the locking cap is configured to engage with the threaded section of the tip holder and to retain the lockable swivel within the cavity of the tip holder; and a spring disposed between the lockable swivel and the locking cap, wherein... When the locking cap is loosely installed, it allows the tip held in the lockable swivel to roll, pitch, and yaw while maintaining accurate θ-registration, wherein when the locking cap is securely installed, the tip held in the lockable swivel is locked in terms of roll, pitch, and yaw, wherein the tip holder includes an upper section configured to hold in the die bonding system, wherein the spring is configured to bias the tip held in the lockable swivel to a neutral position, wherein the lockable swivel includes ball profiles on its top and bottom sides, and wherein the tip holder and the locking cap include corresponding ball profiles on their bottom and top sides, respectively.

[0040] The features and advantages described herein are not exhaustive, and in particular, those skilled in the art will understand many additional features and advantages from the drawings, description, and claims. Furthermore, it should be noted that the language used in the specification has been chosen primarily for readability and pedagogical purposes and does not limit the scope of the subject matter of the invention. Attached Figure Description

[0041] Figure 1 This is a cross-sectional view of a self-aligned tip system using coupled anti-rotation features, illustrating its anatomical structure according to an embodiment of the present disclosure, wherein the tip is locked in a neutral position;

[0042] Figure 2This is an exploded view of a self-aligned tip system using coupled anti-rotation features according to embodiments of the present disclosure;

[0043] Figure 3 This is an exploded view of a self-aligned tip system using coupled anti-rotation features according to embodiments of the present disclosure;

[0044] Figure 4 This is an exploded view of a self-aligned tip system using pin-type anti-rotation features according to an embodiment of the present disclosure.

[0045] Figure 5 This is an exploded view of a self-aligned tip system using pin-type anti-rotation features according to an embodiment of the present disclosure.

[0046] Figure 6 This is a schematic diagram illustrating a self-aligned tip system using a pin-type anti-rotation feature according to an embodiment of the present disclosure, wherein the tip is locked in a neutral position;

[0047] Figure 7 This is a schematic diagram illustrating a self-aligned tip system using a coupled anti-rotation feature according to an embodiment of the present disclosure, wherein the tip is locked in an inclined position;

[0048] Figure 8 This is a schematic diagram illustrating a self-aligned tip system using a coupled anti-rotation feature according to an embodiment of the present disclosure, wherein the tip is in an unlocked configuration;

[0049] Figure 9 This is a schematic diagram illustrating a self-aligned tip system using a coupled anti-rotation feature according to an embodiment of the present disclosure, wherein the tip is locked in a neutral position, and the system includes a magnet configured to bias the tip into the neutral position;

[0050] Figure 10 This is a cross-sectional view of a locking cap according to an embodiment of the present disclosure;

[0051] Figure 11 This is a cross-sectional view of a lockable swivel according to an embodiment of the present disclosure;

[0052] Figure 12 This is a cross-sectional view of a tip holder according to an embodiment of the present disclosure;

[0053] Figure 13 This is a side view of a tip held by a tip holder including a locking cap, according to an embodiment of the present disclosure;

[0054] Figure 14 This is a perspective view of a tip held by a tip holder including a locking cap, according to an embodiment of the present disclosure; and

[0055] Figure 15This is a perspective view of a self-aligned tip system held by a turntable according to an embodiment of the present disclosure.

[0056] This will be achieved through reading and understanding the various aspects described in this article. Figure 1 The following detailed description is provided to better understand these and other features of embodiments of the invention. The drawings are not intended to be drawn to scale. For clarity, not every component may be labeled in each figure. Detailed Implementation

[0057] As a preliminary matter, for the purposes of this disclosure, the X, Y, and Z axes should be understood to refer to three orthogonal linear axes, while "T" (which may also be referred to as the Theta or θ) refers to the rotation axis.

[0058] Thermopress bonding is a method for bonding a die (also known as a chip) to a substrate. It is sometimes also called diffusion bonding, pressure bonding, thermopress welding, or solid-state welding. This process utilizes surface diffusion, grain boundary diffusion, and bulk diffusion to physically and electrically connect the die to the substrate.

[0059] Flatness errors always exist in both the pick-and-place machinery and the customer's die / substrate. These errors make robust die-to-substrate attachment a challenge, especially when no solder or preforms (such as certain types of eutectic bonding) are used. Embodiments of this disclosure address this issue by employing both global flatness correction of the pick-and-place gantry / bed tooling and the option to use a fully flexible tip 104 to help address the varying flatness errors of the customer's die and substrate.

[0060] In embodiments, the die placement system described herein utilizes a novel self-aligned tip system 100 to ensure die-to-substrate flatness without requiring calibration prior to each pick-and-place operation. More specifically, embodiments utilize a tip 104 held by a tip holder 102, adjustablely but lockably held by the self-aligned tip system 100, to assist die placement / attachment. This self-aligned tip system 100 provides global correction for flatness errors that may exist between the die and substrate, regardless of whether these errors originate from gantry misalignment (i.e., die-side misalignment) or machine deck tooling misalignment (i.e., substrate-side misalignment). In embodiments, this is accomplished by self-aligning the tip 104 to a die having non-parallel top and bottom surfaces.

[0061] For reference Figure 1This illustrates the anatomy of a self-aligned tip system 100 according to an embodiment of the present disclosure. More specifically, the self-aligned tip system 100 is configured to hold the tip 104 to allow for full tumble, pitch, and yaw rotation while maintaining accurate θ-registration, thereby ensuring that the die held by the tip 104 is planar with the substrate attached thereto. Embodiments utilize a lockable swivel 114 and, in embodiments, a ball system having elements disposed in a locking cap 106, a tip holder 102, and a lockable swivel 114 to achieve θ-registration, allowing relative movement between the tip 104 and the self-aligned tip system 100. Figure 2 and 3 It provides a better breakdown diagram showing how the components work together.

[0062] In an embodiment, the tip holder 102 includes at least one (in an embodiment, multiple) vents 108 configured to allow vacuum and / or positive pressure to be transmitted through the tip holder 102 to the tip 104 held therein, thereby particularly allowing the tip 104 to be programmably locked or floated.

[0063] In an embodiment, the vent 108 further allows vacuum and / or positive pressure to be transmitted through the tip 104 mounted therein, thereby particularly allowing the die to be held to the tip 104 via vacuum. By using positive pressure, air is applied to the spring-loaded ball profile to help the tip 104 float to engage with the surface of the die. In such embodiments, vacuum can also be used to lock the tip 104 in place.

[0064] In the embodiments (e.g.) Figures 1 to 3 In the embodiment depicted, the tip holder 102 includes a coupler 112 configured to allow the tip 104 to fully tumble, pitch, and yaw while maintaining accurate θ-registration; in this embodiment, the coupler 112 is a universal joint disc. The coupler 112 of this embodiment utilizes a plurality of pins 110 that are partially loosely positioned in the tip holder 102 and partially positioned in a lockable swivel 114 to allow relative movement between the two. In this embodiment, the slotted disc 112 is inserted between the tip holder 102 and the lockable swivel 114.

[0065] In other embodiments (e.g.) Figure 4 and 5 In the embodiments depicted, at least one locating pin 110 is included to rotatably secure the lockable swivel 114, with the previously described coupler 112 added in one embodiment and in another embodiment replacing the coupler 112, while still allowing the tip 104 to fully tumble, pitch, and yaw and maintain accurate θ registration.

[0066] Figure 6 and 7The description depicts the aforementioned ability of the tip 104 to fully roll, pitch, and yaw while maintaining accurate θ registration. Figure 6 and 7 A pin-type embodiment of the self-aligning tip system 100 locked in the neutral position and a coupled embodiment of the self-aligning tip system 100 locked in the tilted position are shown respectively. As can be seen with reference to the figures, when the locking cap 106 is tightened, the internal spring 116 is compressed and there is no gap between the locking cap 106, the lockable swivel 114 and the tip holder 102, thereby effectively locking the angular alignment.

[0067] In one embodiment, the tip holder 102 is sized to accommodate a standard tip 104, thereby allowing it to be used with off-the-shelf components.

[0068] In an embodiment, the self-aligning tip system 100 has the capability to operate in a self-aligning mode for individual pickup or to align and lock in a "locked mode" for global placement on a non-horizontal surface. In an embodiment, this tip locking feature is achieved by tightening a locking cap 106, which, in an embodiment, is a knurled cap 106 configured to screw onto the tip holder 102 and configured to clamp all rotating engagement surfaces (i.e., clamping the inner surface of the lockable swivel 114 to the ball profile disposed in the back of the locking cap 106 and clamping the outer surface of the lockable swivel 114 to the ball profile disposed in the tip holder 102) to lock them together. This feature in Figure 8 The best explanation is in the middle. Figure 8 The self-aligning tip system 100 is depicted in an unlocked state (i.e., the locking cap 106 is relatively loose, allowing the internal spring 116 to push open the corresponding surfaces of the lockable swivel 114, the ball profile disposed in the tip holder 102, and the ball profile disposed on the back side of the locking cap 106) to allow the tip 104 to self-align during die engagement operations. More specifically, when the locking cap 106 is released, the spring 116 decompresses and a gap exists between the lockable swivel 114 and adjacent elements, allowing a change in the angle between the tip 104 and the tip holder 102. In this configuration, the spring 116 keeps the associated ball profile seated and biased toward a neutral position.

[0069] In an embodiment, when tip 104 is in the unlocked position, tip 104 is configured to create frictionless tip 104 alignment using a sudden or steady airflow through vent 108 in tip 104, thereby reducing the downward force normally required to seat tip 104 against the top of the die. Alternatively, a vacuum may then be used to temporarily lock tip 104 in place.

[0070] In one embodiment, the tip 104 is aligned with a rotation center located at the bottom of the die to help reduce die scuffing (i.e., relative movement in the X and / or Y directions when the die contacts the tip 104). Other locations of the rotation center can be made available by customization when processing dies of different thicknesses. In one embodiment, the customization of the rotation center is accomplished by altering the shape of the lockable swivel 114, the tip holder 102, and / or the swivel profile disposed on the back side of the locking cap 106.

[0071] In one embodiment, the internal spring 116 biases the self-aligning tip system 100 to return to a neutral position after the die has been placed.

[0072] In the embodiments (e.g.) Figure 9 In the embodiments depicted, the self-aligned tip system 100 employs a magnetically neutral circuit 900 using a magnet 900 disposed in the tip holder 102, instead of or as a supplement to the spring 116. In such embodiments, the magnet 900 essentially provides the same function as the spring 116, but allows for more flexible operation in some cases. In this embodiment, the magnet 900 is used instead of the spring 116.

[0073] In one embodiment, the tip 104 uses a clamp-type tip retainer, wherein the lockable swivel 114 acts as a clamp, thereby allowing the use of a large number of off-the-shelf standard tips 104. In another embodiment, the locking cap 106 includes a preloaded locking tab configured to prevent the lockable swivel 114 from rotating relative to the self-aligning tip system 100 when tightened.

[0074] This design allows for less-than-perfect flatness in pick-and-place or bare plate joining systems, machine gantry cranes, and deck tools. This can be achieved by simply flattening the tip 104 to the surface requiring compensation to ensure flatness and tightening the locking cap 106 to capture that position.

[0075] The design also allows customers to manufacture dies / substrates with a greater flatness error than is typically allowed by simply releasing the locking cap 106 and allowing the tip 104 to enter a full angular compliance mode within the compliance limits of the lockable swivel 114, in which the tip 104 automatically flattens the die held by the tip 104 onto the substrate in each die bonding operation.

[0076] Figure 10 , 11 Views of the individual components that make up the aforementioned assembly are provided in section 12.

[0077] To be more specific, Figure 10 A lockable cap 106 according to an embodiment of the present disclosure is depicted, having an inner ball profile configured to engage with an inner ball profile disposed in a lockable swivel 114.

[0078] For reference Figure 11 The present disclosure illustrates and depicts a lockable swivel 114 including an inner swivel profile and an outer swivel profile according to an embodiment of the present disclosure, which also includes an integrated clamping ring configured to retain a tip 104.

[0079] Figure 12 A cross-sectional view is shown of a tip retainer 102 comprising a threaded portion configured to receive a locking cap 106, according to an embodiment of the present disclosure.

[0080] For reference Figure 13 and 14 These figures show the self-aligned tip system 100 of the embodiment as a perspective view, thereby detailing its appearance.

[0081] For reference Figure 15 ,For example Figure 15 Embodiments of the described examples provide a thermocompression bonding system comprising an improved die placement system that allows for efficient placement of multiple die types by a single die placement system during die placement cycles, resulting in improved cycle time and accuracy. This is accomplished by minimizing movement of the die placement system in operations involving the placement of multiple dies on a single substrate, where the tips 104 must be exchanged to accommodate dies of different sizes by incorporating a die placement head holding turntable 1500 and a tool's rotating holder into the die placement system. In one embodiment, the turntable 1500 of this system carries a plurality of self-aligned tip systems 100, each carrying a tip 104 required for a specific application, without requiring the die placement system to return to a conventional tool holder between die placement operations involving dies of different sizes. In another embodiment, the turntable 1500 may incorporate a permanent magnet, an electromagnet, a vacuum channel, or a combination thereof to hold the self-aligned tip system 100 when not in use. Those skilled in the art will understand other suitable components for holding the self-aligned tip system 100 within the turntable 1500.

[0082] The foregoing description of embodiments of this disclosure has been presented for illustrative purposes. It is not intended to be exhaustive or to limit the disclosure to the precise forms disclosed. Many modifications and variations may be made in light of this disclosure. It is intended that the scope of this disclosure be limited not by this detailed description, but by the appended claims.

[0083] Several embodiments have been described. However, it should be understood that various modifications may be made without departing from the scope of this disclosure. Although the operations are depicted in a specific order in the diagrams, this should not be construed as requiring such operations to be performed in the specific order shown or in a sequential order, or to perform all the illustrated operations to achieve the desired result.

Claims

1. A self-aligned tip system, comprising: A tip retainer, comprising a threaded section disposed on its distal end and a hollow inner cavity; A lockable swivel is disposed in the hollow cavity of the tip holder, the lockable swivel including a central hole configured to retain the tip; and A locking cap includes a central hole configured to allow a tip to pass through it, wherein the locking cap is configured to screw onto the threaded section of the tip holder and to retain the lockable swivel within the cavity of the tip holder. When the locking cap is loosely installed, the tip remaining in the lockable swivel is allowed to roll, pitch, and yaw while maintaining accurate θ registration. When the locking cap is securely installed, the tip held in the lockable swivel is locked in terms of roll, pitch and yaw.

2. The self-aligned tip system of claim 1, wherein the tip holder comprises an upper section configured to be held in a die bonding system.

3. The self-aligning tip system of claim 1, wherein the lockable swivel includes a swivel profile on its top and bottom sides, and wherein the tip holder and the locking cap include corresponding swivel profiles on their bottom and top sides, respectively.

4. The self-aligning tip system of claim 1, further comprising a spring disposed between the lockable swivel and the locking cap.

5. The self-aligning tip system of claim 4, wherein the locking cap and lockable swivel include a spring seat configured to position the spring.

6. The self-aligned tip system of claim 4, wherein the spring is configured to bias the tip held in the lockable swivel to a neutral position.

7. The self-aligned tip system of claim 4, further comprising a magnet disposed in the tip holder.

8. The self-aligned tip system of claim 7, wherein the magnet is configured to bias the tip held in the lockable swivel to a neutral position.

9. The self-aligned tip system of claim 1, further comprising a magnet disposed in the tip holder.

10. The self-aligned tip system of claim 9, wherein the magnet is configured to bias the tip held in the lockable swivel to a neutral position.

11. The self-aligning tip system of claim 1, wherein the self-aligning tip system is configured such that tip alignment occurs at a rotational center located at the bottom of the bare die held by the tip by the lockable swivel.

12. The self-aligned tip system of claim 1, further comprising at least one vent disposed in the tip holder.

13. The self-aligned tip system of claim 12, wherein the self-aligned tip system is configured to lock the tip in place using a vacuum.

14. The self-aligned tip system of claim 1, further comprising a tip held in the lockable swivel, wherein the tip includes at least one vent configured to allow positive pressure and / or vacuum to be transferred from the back side of the tip to its distal end, the distal end being configured to mount a die to a substrate.

15. The self-aligning tip system of claim 14, wherein when the tip is in an unlocked position, the tip is configured to reduce friction associated with tip alignment by utilizing a sudden or steady airflow through the at least one vent disposed therein.

16. The self-aligning tip system of claim 1, wherein the lockable swivel utilizes a clamp retaining system to hold the tip.

17. The self-aligning tip system of claim 1, wherein the locking cap further comprises a preloaded locking tab configured to prevent the lockable swivel from rotating relative to the self-aligning tip system after tightening.

18. A method for planarizing a tip with a substrate, the method comprising: Using the self-aligned tip system according to claim 1: Keep the tip within the lockable swivel; The locking cap is released, thereby allowing the tip to roll, pitch, and yaw while maintaining accurate θ registration; Make the tip contact the substrate; and Tighten the locking cap to lock the tip’s roll, pitch and yaw.

19. A die bonding system, comprising: A rotary table includes a rotating measuring device and a plurality of self-aligning tip system holding portions positioned substantially adjacent to its periphery, wherein each self-aligning tip system holding portion includes two concentric holes: a first hole and a second hole, the first hole extending completely through the rotary table and the second hole positioned on a side of the rotary table opposite to and concentric with the first hole, wherein the second hole extends only partially into the rotary table, and wherein, after rotation, each of the plurality of self-aligning tip system holding portions is alignable with a tool; and An electric motor, configured to rotate the turntable upon activation, At least one of the plurality of self-aligned tip system holding portions includes the self-aligned tip system according to claim 1.

20. A self-aligned tip system, comprising: A tip retainer, comprising at least one vent, a threaded section disposed at its distal end, and a hollow inner cavity; A lockable swivel includes a central hole configured to retain the tip; A locking cap is disposed in the hollow cavity of the tip holder, and the lockable swivel includes a central hole configured to allow a tip to pass through therethrough, wherein the locking cap is configured to engage with the threaded section of the tip holder and to retain the lockable swivel inside the cavity of the tip holder; and A spring, which is positioned between the lockable swivel and the locking cap, When the locking cap is loosely installed, the tip remaining in the lockable swivel is allowed to roll, pitch, and yaw while maintaining accurate θ registration. When the locking cap is securely installed, the tip held in the lockable swivel is locked in terms of roll, pitch, and yaw. The tip holder includes an upper section configured to be held in the die bonding system. The spring is configured to bias the tip held in the lockable swivel to a neutral position. The lockable swivel includes a swivel profile on its top and bottom sides, and the tip retainer and locking cap include corresponding swivel profiles on their bottom and top sides, respectively.

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