Method for bonding chips and system for carrying out method

Abstract

To provide chip bonding method and system that include collectively bonding a plurality of chips to enhance productivity / throughput.SOLUTION: In a bonding system, a method for bonding chips includes a step of actuating a first bonding head to apply a first force to a first chip while the first chip is in contact with a bonding surface, thereby partially bonding the first chip to the bonding surface, actuating a second bonding head to apply a second force to a second chip while the second chip is in contact with the bonding surface, thereby partially bonding the second chip to the bonding surface, actuating the first bonding head and the second bonding head in cooperation to apply a third force to the first chip and the second chip, thereby completely bonding the first chip and the second chip to the bonding surface. The magnitude of the third force is greater than the magnitude of the first force and the magnitude of the second force.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to methods of bonding chips, including bonding multiple chips together. [Background technology]

[0002] Advanced packaging techniques require precise and accurate control and placement of chips. To increase productivity / throughput, it is desirable in the art to use multiple bond heads simultaneously to bond multiple source chips to a bond surface. However, even when multiple bond heads are operated simultaneously as much as possible, one chip of a bond head always contacts the bond surface just before another chip of the other bond head. This initial contact by one chip on one bond head causes the carriage supporting the bond surface to tilt about its center of gravity. The tilt of the carriage about its center of gravity leads to increased and unstable alignment of the chips on the remaining bond heads.

[0003] FIG. 12 shows a schematic side view of a bonding system in which tilting around the carriage's center of gravity occurs. The bonding unit 1 includes two bonding heads 2 coupled to a bridge 3. Under the bonding heads 2 is a carriage 4 holding a substrate chuck 5 carrying a substrate 6. The carriage 4 includes a stage support unit 7, such as a bearing, such as an air bearing, a mechanical bearing, or a magnetic levitation bearing, on a base 8. FIG. 12 shows a moment when the bonding heads 2 are about to bond two chips 9 to a bonding surface 10 on the substrate 6. However, as mentioned above, even if two chips 9 are simultaneously bonded to the bonding surface 10, one chip will always contact the bonding surface 10 first. As shown in FIG. 12, when this happens, the carriage 4, including all the structures it carries, rotates in a direction 11 about the center of gravity cg. This rotation creates an offset angle 12 that negatively affects the alignment of the second chip that contacts the bonding surface 10 after the first chip has contacted the bonding surface 10. The rotation creates an alignment error for the bonding of the next chip. Since the amount of tilt varies depending on the bonding position, it is very difficult to compensate for such additional errors. In the system of Fig. 12, a tilt of the carriage 4 of more than 0.2 μrad caused by the bonding process will result in an alignment error of the order of, for example, more than 10 nm. The relationship between the alignment error and the tilt can be a function of the distance between the center of gravity cg of the carriage 4 and the bonding direction (z-axis).

[0004] Therefore, there is a need in the art for a method and system for bonding multiple source chips to a bonding surface while eliminating or minimizing alignment errors caused by tilting of the carriage about its center of gravity. Summary of the Invention

[0005] A method for bonding chips includes actuating a first bond head to apply a first force to a first chip while the first chip is in contact with a bonding surface, thereby partially bonding the first chip to the bonding surface, actuating a second bond head to apply a second force to a second chip while the second chip is in contact with the bonding surface, thereby partially bonding the second chip to the bonding surface, and jointly actuating the first and second bond heads to apply a third force to the first and second chips, wherein a magnitude of the third force is greater than a magnitude of the first force and a magnitude of the second force.

[0006] A system for bonding chips includes a first bond head, a second bond head, a substrate chuck for holding a substrate having a bonding surface, one or more processors, and one or more memories storing instructions that, when executed by the one or more processors, cause the system to: actuate a first bond head to apply a first force to a first chip while the first chip is in contact with the bonding surface to thereby partially bond the first chip to the bonding surface, actuate a second bond head to apply a second force to a second chip while the second chip is in contact with the bonding surface to thereby partially bond the second chip to the bonding surface, and actuate the first bond head and the second bond head in conjunction to apply a third force to the first chip and the second chip to fully bond the first chip and the second chip to the bonding surface, where the third force is greater than the first force and the second force.

[0007] A method for manufacturing a plurality of articles includes the steps of: actuating a first bonding head to apply a first force to a first chip while the first chip is in contact with a bonding surface, thereby partially bonding the first chip to the bonding surface; actuating a second bonding head to apply a second force to the second chip while the second chip is in contact with the bonding surface, thereby partially bonding the second chip to the bonding surface; actuating the first bonding head and the second bonding head in conjunction to apply a third force to the first chip and the second chip to completely bond the first chip and the second chip to the bonding surface, where the third force is greater than the first force and the second force, and singulating a product substrate to manufacture the plurality of articles. [Brief description of the drawings]

[0008] Embodiments are illustrated by way of example and not limitation in the accompanying figures.

[0009] [Figure 1] 1 is a schematic side view of a joint system according to an illustrative embodiment;

[0010] [Diagram 2] 2 is a flowchart of a method for bonding chips using the bonding system of FIG. 1 according to an exemplary embodiment.

[0011] [Diagram 3] A partially enlarged view of Figure 1.

[0012] [Figure 4] 4 is a flow chart of an exemplary embodiment of a method for bonding chips.

[0013] [Diagram 5] 1 after a tip bending step, according to an exemplary embodiment. FIG.

[0014] [Figure 6]2 is a close-up view of a portion of FIG. 1 at the moment when the first chip contacts the mating surface, according to an exemplary embodiment.

[0015] [Figure 7] 2 is a close-up view of a portion of FIG. 1 at the moment when the second chip contacts the bonding surface, according to an exemplary embodiment.

[0016] [Figure 8] 1 at a moment when the third chip contacts the bonding surface, according to an exemplary embodiment.

[0017] [Figure 9] 1 at a moment when a fourth chip contacts the bonding surface, according to an exemplary embodiment. FIG.

[0018] [Figure 10] 2 is a close-up view of a portion of FIG. 1 at the moment when the chip is fully bonded to the bonding surface, according to an exemplary embodiment.

[0019] [Figure 11] 2 is a close-up view of a portion of FIG. 1 at the moment the tip is released from the bond head, according to an exemplary embodiment.

[0020] [Figure 12] FIG. 1 is a schematic side view of a joint of a joint system tilting about its center of gravity during jointing.

[0021] Those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale, for example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements to help understand implementations of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] The following description, together with the drawings, is provided to aid in understanding the teachings disclosed herein. The following discussion focuses on particular implementations and implementations of the teachings. This focus is provided to help explain the teachings and should not be construed as a limitation on the scope or applicability of the teachings.

[0023] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The materials, methods, and examples are illustrative only and are not intended to be limiting. Unless explained herein, many details regarding specific materials and processing operations are conventional and can be found in textbooks or other sources in the art.

[0024] FIG. 1 shows a schematic side view of a bonding system 100 according to an exemplary embodiment. As shown in FIG. 1, the bonding apparatus 100 includes a chip source unit 102, a chip transport and activation unit 104, and a chip bonding unit 106. The chip source unit 102 is the portion of the overall bonding system 100 that contains the source chips to be used in the bonding process. The chip transport and activation unit 104 is the portion of the overall bonding system 100 that transports the chips from the chip source unit 102 to the chip bonding unit 106. In another configuration, the chip source unit may be a separate device. Similarly, the chip transport and activation unit may be a separate device. Also, the chip transport and activation unit 104 activates the source chips to prepare them for bonding. In an alternative embodiment, the chip transport and activation unit 104 activates a plurality of chips 124 before the chips are placed in the chip source unit 102. The chip bonding unit 106 accepts the activated chips and performs bonding. Details of each of these units are described in detail below.

[0025] The chip source section 102 includes one or more sources for chips. For example, as shown in FIG. 1, the chip source section may include a substrate 114 with chips 124 mounted thereon, held by a source chuck 110, and / or may include a front-opening unified universal pod 112 (known in the art as a "FOUP"). A FOUP may include multiple substrates 114 and multiple chips 124. Other chip sources known in the art may be used for the chip source section 102, such as a tray, adhesive tape in a frame, adhesive layer on a rigid substrate, etc. As used herein, chip means an integrated circuit, also called a microchip, computer chip, etc. A chip may be defined as a small block of semiconductor material on which a given functional circuit is fabricated. In the context of a wafer / substrate that has been divided into individual chips, the chip is referred to as a die. A chip typically carries a set of integrated electronic components and circuits formed thereon by patterning, coating, etching, doping, plating, singulation, etc. Chips typically have electrical functionality such as memory, logic circuits, field programmable gate arrays (FPGAs), accelerator circuits, application specific integrated circuits (ASICs), security co-processors, graphics processing units (GPUs), machine learning circuits, special purpose processors, controllers, devices, electrical circuits, arrays of passive components, etc. Chips may also be MEMS devices, optical devices, electro-optical devices, etc.

[0026] The chip transfer and activation section 104 includes a transfer robot 126 that can lift and transfer the substrate 114 to the second substrate chuck 130 in the bonding section 106. As understood in the art, the transfer robot 126 generally includes a hand and a robot arm that provides multiple dimensions of motion to lift, transfer, and place the substrate from one location to another, such as from one substrate chuck to another or from a substrate storage location to a substrate chuck. The transfer robot 126 can be any suitable device known in the art, for example, a robot such as the wafer transfer robot RR756L15 provided by ROHZE Corporation, Fukuyama, Hiroshima, Japan. The chip transfer and activation section 104 further includes an activation device 128. The activation device 128 is a device that prepares the transferred chip for hybrid bonding. Hybrid bonding is a chip bonding technique in which electrically insulating (silicon dioxide) chip surfaces with embedded metal (e.g., copper) pads are brought into contact with each other. The metal pads are aligned with each other while the electrically insulating surfaces are bonded to each other via direct contact. Heat is then applied to the joining structure, which causes the metal pads to expand more against the electrically insulating material and come into contact with each other, thereby forming an electrical connection between the chips. In an exemplary embodiment, the activation device 128 may include a fluid source that applies, for example, deionized water, and a plasma source to activate the surfaces of the chips before they are transported by the transfer robot 126. Depending on the material of the chips (i.e., the dielectric), when the activated chip comes into contact with another chip, a fusion bond is formed between the dielectric surfaces of the two chips.

[0027] The interface 106 includes a second substrate chuck 130 for receiving the substrate 114 having the chips transferred by the transfer robot 126 and activated by the activation device 128. The second substrate chuck 130 is also referred to herein as an intermediate substrate chuck. The interface 106 may include a bridge 132 to which the intermediate substrate chuck 130 is attached. In an alternative embodiment, the intermediate substrate chuck 130 is attached to the base 144 instead of the bridge 132. The interface 106 also includes a plurality of bonding heads 134 attached to the bridge 132. In one embodiment, the bonding head 134 may include a peripheral chuck region that holds the backside of the chip 124 along its periphery and a central pressure source that bends the chip 124 held along its periphery. In one embodiment, the bonding head 134 includes a chucking portion that holds the chip 124 and a pressurizing cavity behind the chucking portion that bends the chucking portion, so that the chip 124 held by the chucking portion may also bend. In one embodiment, the bond head 134 may include one or more actuators to move the chip chuck in at least the z-direction toward the product substrate chuck 136. The bond head 134 may include one or more actuators to move the chip chuck in at least one of five directions (x, y, tip, tilt, and rotate). The actuators may be voice coil motors, piezoelectric motors, linear motors, nut and screw motors, piezo actuated stages, brushless DC motor stages, DC motor stages stepper motors configured to move the chip chuck to and from the product substrate chuck 136 and to apply a controlled force to the chip when the chip is in contact with the bonding surface 140. The chip chuck may hold the chip to the chuck surface using vacuum, electrostatic force, electromagnetic force, mechanical gripping force, or any other method that releasably holds the chip to the chuck surface of the bond head 134. The bonding portion 106 further includes a product substrate chuck 136 that holds a product substrate 138. The product substrate 138 has a bonding surface 140. Bonding surface 140 in the illustrated embodiment is the top surface of product substrate 138. In another exemplary embodiment, the bonding surface may be the surface of a chip already on product substrate 138.That is, the bonding described herein may be used to bond source chips onto a surface of a product substrate and / or to a surface of a product chip on a product substrate. As shown in Figure 1, product substrate chuck 136 is carried by carriage 142. Figure 1 shows that carriage 142 includes stage support units 118, such as bearings. The bearings may be air bearings, mechanical bearings, or magnetic levitation bearings from a base plate.

[0028] The bonding section 106 may further include a number of alignment devices 146 and a number of transfer heads 148, all carried by the carriage 142. Each of the number of transfer heads 148 may include any one of a variety of ways to hold a chip, including, but not limited to, a Bernoulli chuck, a suction nozzle, an electrostatic chuck, an edge-grasping chuck, a latching mechanism, or any way to releasably hold a chip. Each of the number of transfer heads 148 may include an actuator for moving at least in the z-direction toward and away from the bridge 132. The number of alignment devices 146 are used to check the alignment of the chips on the number of bond heads 134 after transferring the chips to the number of bond heads 134. Each alignment device may be a microscope, a camera, an interferometer, or any type of measuring device capable of measuring the position of each chip on the nanometer scale. The information provided by the number of alignment devices 146 allows an operator to know if each chip is at a target position within an acceptable amount of error. The alignment devices 146 may be any suitable device known in the art, for example, a 20x microscope with a 5 megapixel camera, such as a CI-5MGMCL from Canon Inc., Tokyo, Japan. The transfer heads 148 are used to transfer the chips from the intermediate substrate 116 held on the intermediate substrate chuck 130 to the bonding heads 134. Each of the transfer heads 148 may include any one of a variety of methods of holding the chip, including, but not limited to, a Bernoulli chuck, a suction nozzle, an electrostatic chuck, an edge-gripping chuck, a latching mechanism, or any method of releasably holding the chip. Each of the transfer heads 148 may include an actuator for moving in at least the z-direction toward and away from the bridge 132.

[0029] The number of the bonding heads of the multiple bonding heads is at least two, but may be eight or sixteen. The arrangement of the multiple bonding heads may be in the form of columns and rows of 1×2, 2×2, 2×2, 1×3, 3×1, 2×3, 2×3, 3×2, 3×3, 4×1, 1×4, 4×2, 2×4, 3×4, 4×3, 4×4, etc. That is, when m is 1 to 4 and n is 1 to 4, the number of bonding heads is expressed as "m×n". In the example shown in FIG. 1, at least one of m and n is 4. The number and arrangement of the transport heads of the multiple transport heads may be the same as the number and arrangement of the bonding heads. Alternatively, the number and arrangement of the transport heads of the multiple transport heads may be greater than the number and arrangement of the bonding heads.

[0030] The joint 106 may further include a first microscope 150 on the carriage 142 and a second microscope 152 on the bridge 132. The first microscope 150 on the carriage 142 is movable along the base plate 144 with the multiple transport heads 148, the product substrate chuck 136, and the multiple alignment devices 146. The first microscope 150 faces upward in a direction toward the intermediate substrate chuck 130. The first microscope 150 functions to measure the positions of the multiple chips on the intermediate substrate 116. The second microscope 152 faces downward in a direction toward the product substrate chuck 136. The second microscope 152 functions to measure the positions of the chips on the product substrate 138. Each of the first and second microscopes may be any suitable device known in the art, for example, a 20x microscope with a 5 megapixel camera, such as a CI-5MGMCL from Canon Inc. of Tokyo, Japan.

[0031] The bonding system 100 may be coordinated, controlled, and / or directed by one or more processors 154 (controllers) in communication with one or more components and / or subsystems, such as the chip source unit 102, the chip transport and activation unit 104, the bonding unit 106, the source chuck 110, the FOUP 112, the transport robot 126, the activation device 128, the intermediate substrate chuck 130, the multiple bonding heads 134, the product substrate chuck 136, the carriage 142, the multiple alignment devices 146, the multiple transport heads 148, the first microscope 150, and the second microscope 152. The processor 154 may operate based on instructions in a computer-readable program stored in a non-transitory computer memory 156. The processor 154 may be or include one or more of a CPU, an MPU, a GPU, an ASIC, an FPGA, a DSP, and a general-purpose computer. The processor 154 may be a dedicated controller or a general-purpose computing device adapted to be a controller. Examples of non-transitory computer readable memory may include, but are not limited to, RAM, ROM, CDs, DVDs, Blu-Ray, hard disk drives, network attached storage (NAS), intranet connected non-transitory computer readable storage devices, and internet connected non-transitory computer readable storage devices. All of the steps described herein may be performed by the processor 154.

[0032] FIG. 2 shows a flow chart of a method for bonding a chip 200 using the bonding system 100. The bonding method 200 begins with step S202, which involves actuating a first bonding head to apply a first force to a first chip while the first chip is in contact with the bonding surface. However, several steps that may be part of the bonding method may occur before the first step shown in FIG. 2. For example, the following additional steps may be performed before step S202. First, desired chip information may be received, including the quality required for the chip, where it should be placed on the bonding surface. The quality of the chip may be defined as the maximum clock rate, the percentage of transistors that function at one or more specified clock rates, local cache size, thermal conductivity, and other characteristics that affect the performance of the chip, which may vary depending on the manufacturing performance of the chip. After the chip information is received, if it has not yet been activated, the transfer robot 126 carries the source substrate 114 through the activation device 128 and activates the chip in the manner described above, after which the source substrate 114 is received by the chip bonding unit 106. After the chips have passed through the activation device 128 in their activated state, the transfer robot 126 carries the source substrate 114 to a second substrate chuck 130 at the chip bonding portion 106. In an alternative embodiment, the chips on the source substrate 114 are already activated and transferred directly from the chip source portion 102 to the bonding portion 106.

[0033] Next, the source substrate 114 with the activated chips 124 is chucked to the second substrate chuck 130. Next, once the source substrate 114 with the activated chips 124 is mounted on the second substrate chuck 130, the positions of the chips 124 can be measured using the first microscope 150. This step can be performed by moving the carriage 142 along the base plate 144 until the first microscope 150 is under the chips 124. If the feedback from the first microscope 150 indicates that a particular chip of the chips 124 is out of tolerance, a replacement source substrate 114 needs to be prepared. If the feedback from the first microscope 150 indicates that the chips 124 are properly positioned within the tolerance, the method can proceed.

[0034] The first set of chips from the source substrate 114 can then be transferred to the multiple bonding heads 134. This step can be performed by first moving the carriage 142 along the base plate 144 until the multiple transfer heads 148 are under the multiple chips 124. The multiple transfer heads 148 can include the same number of heads with the same pitch as the multiple bonding heads 134. The multiple transfer heads 148 are configured to mirror the multiple bonding heads 134, such that the multiple transfer heads 148 can transfer up to as many chips as the multiple bonding heads can bond in a single bonding step. The multiple transfer heads 148 can pick up the first set of chips from the source substrate 114, for example, by activating a vacuum force. The multiple transfer heads 148 can maintain the vacuum force while the multiple transfer heads 148 carrying the first set of chips are moved via the carriage 142 to a position under the multiple bonding heads 134. Either the multiple transport heads 148 or the multiple bond heads 134 move towards the other (or both move simultaneously) until they are in position to transfer the first set of chips to the multiple bond heads 134. Once close enough, the vacuum force on the multiple transport heads 148 may be terminated and the vacuum force on the multiple bond heads 134 may be activated, thereby transferring the first set of chips to the multiple bond heads 134. The moment when all of these steps have been performed just prior to step S202 is the moment shown in FIG. 1. That is, at the moment shown in FIG. 1, each bond head 134 is holding a chip and is ready to proceed with bonding.

[0035] Once the above-mentioned initial steps are completed, the bonding method 200 is ready to begin step S202 described above, which involves actuating the first bonding head to apply a first force to the first tip while the first tip is in contact with the bonding surface. The first force may be applied downward in the Z direction. Starting with step S202, all steps are performed within the portion 160 of the bonding system 100. FIG. 3 shows an enlarged view of the portion 160 at the same moment as shown in FIG. 1. That is, as shown in FIG. 3, just before step S202, each bonding head 134 has a tip 124, and the bonding heads 134 are positioned above the bonding surface 140. None of the tips 124 are in contact with the bonding surface 140, and all of the tips 124 are flat (not curved).

[0036] FIG. 4 shows a flow chart of an exemplary embodiment of a bonding method 400, in which steps S402-S406 correspond to step S202 of the method 200 of FIG. 2. That is, steps S402-S406 of the method 400 may be considered as sub-steps that may be performed to complete step S202 of FIG. 2. As shown in FIG. 4, the first step of the bonding method 400 is to move the carriage 142 to a bonding position such that the multiple chips 124 held by the multiple bonding heads 134 are aligned with respect to the bonding surface 140. As mentioned above, in this embodiment, the bonding surface 140 is the surface of the product substrate 138, but the bonding surface may also be the surface of the chip. FIG. 3 shows the moment when step S402 is completed, when the multiple bonding heads 134 holding the multiple chips 124 are above the bonding surface 140 of the product substrate 138.

[0037] The bonding method 400 then proceeds to step S404, where each tip of the plurality of tips 124 is bent. The tip bending may be achieved by back pressure control applied directly to the tip or tip-holding chuck of each bond head 134, as described in U.S. Patent Application No. 18 / 326,473, filed May 31, 2023, the disclosure of which is incorporated herein by reference. FIG. 5 illustrates portion 160 of FIG. 1 at a moment after step S404 is completed. As shown in FIG. 5, each tip 124 is in a bent state. However, none of the tips 124 is closer to the bond surface 140 than any other tip. That is, none of the tips 124 has moved in the Z direction at the time step S404 is completed. In an alternative embodiment, step S404 may be performed as the bond head 134 moves the tip toward the surface of the product substrate 140.

[0038] After all of the tips 124 on the bond head 134 have been bent, the method proceeds to step S406, where a first tip 124a of the bent tips 124 is subjected to an initial force F i At this time, the other curved tips 124b, 124c, and 124d are not in contact with the joining surface 140. The initial force F imay be applied downward in the Z direction by actuating a bonding head holding the tip. FIG. 6 shows portion 160 of FIG. 1 at a moment after step S406 is completed. The first tip 124a may be placed into contact with the bonding surface 140 by an actuator of the bonding head lowering the first tip 124a in the Z direction. As shown in FIG. 6, the first tip 124a is in contact with the bonding surface 140 but remains curved. The first tip 124a contacts the bonding surface 140 at a point along the curved first tip 124a that has a maximum height (i.e., a point along the curved first tip 124a that extends furthest in the Z direction). Typically, this point of maximum height is the center of the tip in the X and Y directions. At the moment the first tip 124a contacts the bonding surface 140, bonding is achieved at the contact point and the first tip 124a is partially bonded to the bonding surface 140. Partial bonding means that the entirety of the face of the first chip 124a that faces the bonding surface 140 is not bonded to the bonding surface. Rather, only the portion of the first chip 124a that is in physical contact with the bonding surface 140 is bonded to the bonding surface 140. In an exemplary embodiment, none of the other curved chips 124b, 124c, 124d are moved upon completion of step S406. However, there may be Z-direction movement of one or more of the other curved chips as long as none of the other curved chips are in full contact with the bonding surface. The amount of force applied when the first chip 124a contacts the bonding surface 140 may be about 5-10% of the amount of force required to conform and flatten the entire chip to the bonding surface 140 and bond the entire chip to the bonding surface. The amount of force depends on the thickness of the chip and the chip-holding chuck. For the same amount of curvature, a thicker chip requires a higher curvature pressure, which causes a higher conforming force. For a silicon chip of 10 mm x 10 mm and 100 μm thick, a typical fitting force is in the range of 2-5 N. Thus, the initial force can be in the range of 100 mN to 500 mN.

[0039] After completing step S406, which is an exemplary embodiment corresponding to completing step S202 of FIG. 3, as described above. That is, after completing step S406, the first bonding head is actuated to apply a first force to the first tip while the first tip is in contact with the bonding surface. Thus, returning to the overall bonding method 200, the method proceeds to step S204, where the second bonding head is actuated to apply a second force to the second tip while the second tip is in contact with the bonding surface. The second force may similarly be applied downward in the Z direction. Steps S408 and S410 of the bonding method 400 are exemplary embodiment steps corresponding to step S204 of the overall bonding method 200.

[0040] In S408, the other curved tip is applied with an initial force F without contacting the other curved tip that is not in contact with the joining surface. i1 at a point along the curved second chip 124b that has the greatest height (i.e., the point along the curved second chip 124b that extends furthest in the Z dimension). At the moment the second chip 124b contacts the mating surface 140, bonding is achieved and the second chip 124b is partially bonded to the mating surface 140. By partially bonded, we mean that, like the first chip, the entire face of the second chip 124b that faces the mating surface 140 is not bonded to the mating surface. Rather, only the portion of the second chip 124b that contacted the mating surface 140 is bonded to the mating surface 140. In an exemplary embodiment, the remaining curved chips 124c, 124d have not been moved upon completion of step S408. However, there may be Z-direction movement of one or more of the other curved chips as long as none of the other curved chips contact the bonding surface. The amount of force applied when the second chip 124b contacts the bonding surface 140 may be about 5-10% of the amount of force required to conform and flatten the entire chip to the bonding surface 140 and bond the entire chip to the bonding surface. For example, the initial force F i The magnitude of the force may be 2-5 N for a 10 mm x 10 mm silicon chip with a thickness of 100 μm. During this process of partially bonding the second chip 124b, the first chip 124a remains partially bonded to the bonding surface 140. As shown in FIG. 7, after step S408 is completed, the two chips 124a and 124b are partially bonded to the bonding surface 140. Also, the two chips 124a and 124b maintain their curved shapes.

[0041] Next, the method proceeds to step S410, where step S408 determines whether or not all of the remaining curved chips that are not yet partially bonded to the bonding surface are bonded to the initial force F. iThis process is repeated until the third chip 124c is placed in contact with the bonding surface at a predetermined distance. That is, in this embodiment, the first chip 124a and the second chip 124b are brought into contact with the third chip 124c, and then the same process is applied to the fourth chip 124d one by one. FIG. 8 shows part 160 of FIG. 1 at the moment when the third chip 124c comes into contact with the bonding surface 140, and FIG. 9 shows part 160 of FIG. 1 at the moment when the fourth chip 124d comes into contact with the bonding surface 140. As described above, in both cases, an initial force F downward in the Z direction having a magnitude of 5 to 10% of the magnitude of the alignment force is applied. i The bent tip is partially bonded to the bonding surface by applying an initial force F i The sizes of the bond heads may all be the same or different. The same process can be applied to any arrangement of bond heads / chips until all the curved chips are partially bonded to the bond surface 140. That is, in the exemplary embodiment, while only four bond heads and four chips are shown in side view, the method can be applied to any arrangement of bond heads (e.g., 1×2, 1×2, 2×2, 1×3, 3×1, 1×3, 1×2, 2×3, 3×2, 3×3, 4×1, 1×4, 4×2, 2×4, 3×4, 4×4, etc.). The process of partially bonding the curved chips is repeated one at a time until all the curved chips are partially bonded to the bond. Once step S410 is completed, all of the curved chips 124a, 124b, 124c, 124d are partially bonded to the bond surface 140, as shown in FIG. 9.

[0042] Returning to the overall bonding method 200, after the second chip is brought into contact with the bonding surface by applying a second force (i.e., an initial force), or in the case of the bonding method 400 of the exemplary embodiment, after step S410, after all the curved chips are partially bonded with the bonding surface, the bonding method 200 proceeds to step S206, where the first bonding head and the second bonding head are jointly actuated (e.g., the first bonding head and the second bonding head are actuated together) to apply a third force, which is greater than the first and second forces, to the first and second chips to fully bond the first and second chips to the bonding surface. Fully bonded in the context of hybrid bonding means that the dielectric surface of the chip aligned with the dielectric surface of the bonding surface of the product surface is matched with the dielectric surface of the bonding surface. The chip and bonding surface include non-dielectric material that is not bonded while the chip is fully bonded to the bonding surface. At a later point in time, the fully bonded chip is annealed, at which point the non-dielectric material forms a bond. That is, the magnitude of the third force is greater than the magnitude of the first force and the magnitude of the second force. Step S206 corresponds to step S412 of the bonding method 400 of the exemplary embodiment. As used herein, "jointly" may include actuating all bond heads to apply the third force at the same time, actuating all bond heads to apply the same third force within 1 second of each other, fully bonding all chips currently on the bond heads within 1-3 seconds, and any amount of time it takes to complete bonding of all chips currently on the bond heads. That is, the time it takes for all chips of a set of chips on a bond head to be fully bonded can be considered "jointly" as long as the transfer head is not yet transferring another set of chips for bonding.

[0043] The third force is a conforming force F that is strong enough to completely flatten the curved chip so that the entire chip surface area is bonded to the bonding surface. c As mentioned above, the initial force F i The magnitude of the compatibility force F c (i.e., F i =0.05Fc ~0.1F c ). Compatibility F c can be oriented downward in the Z direction and can have a magnitude of 2-5 N per chip for 10 mm x 10 mm and 100 μm silicon chips. Thus, the overall bonding method 200 involves applying a first force (initial force) to the first chip, applying a second force (another initial force) to the second chip, and then applying a third force (conforming force) to both the first and second chips jointly. In the exemplary embodiment bonding method 400, in step S412, a conforming force F is applied to all of the curved chips contacting the bonding surfaces. c , 124a, 124b, 124c, 124d are contacted with the mating surface 140 in a curved state using an initial force to partially bond the chips to the mating surface, and then a conforming force is applied to all four of the chips 124a, 124b, 124c, 124d jointly.

[0044] In an alternative parallel embodiment, steps S404, S406, and S408 are performed in parallel for each bond head, and step S412 is performed after all tips have completed step S408. In an alternative parallel embodiment, step S404 may be skipped. If step S404 is skipped, the tip is not bent and the initial force causes less than the entire surface area of ​​the tip to bond to the bond surface, while the conforming force causes the tip to fully conform / bond to the bond surface.

[0045] FIG. 10 illustrates portion 160 of FIG. 1 at the moment when a conforming force is jointly applied to all of the partially bonded curved chips 124a, 124b, 124c, 124d. As shown in FIG. 10, all of the chips 124a, 124b, 124c, 124d have been flattened / uncurved such that the entire surface area of ​​each chip is in contact with the bonding surface 140. When each chip is in full contact with the bonding surface, each entire chip is fully bonded to the bonding surface. Due to the bonding method described herein that uses an initial bonding force to partially bond all of the chips before jointly applying the conforming force, the tilting of the carriage about the center of gravity cg described above is avoided or minimized. This is because the initial force F i The magnitude of the adaptive force F c The larger the fitting force F, the smaller the force F is (e.g., less than 0.2 μrad) so that there is minimal or no rotation about the center of gravity when each chip is partially bonded. Because all the chips are already partially bonded, it is no longer possible for one chip to accidentally contact the mating surface before another chip. c to the tip 124, the carriage 142 can tilt by more than 0.2 μrad. However, the tip 124 is biased by a compliant force F c Since the joint is partially joined before the application of the compliant force F c There is no increase in alignment error due to tilt caused by application of the . Thus, by implementing the methods and systems described herein, the alignment error caused by the bonding process is 10 nm or less.

[0046] After step S412, once all of the chips 124 have been fully bonded to the bonding surface, the bonding method proceeds to step S414, where all of the bonded chips are separated from the bonding head. That is, with one side of the chip still bonded to the bonding surface, the bonding head can separate the other side of the chip being held by the bonding head. Once separated, the bonding process is complete. FIG. 11 shows portion 160 of FIG. 1 after the bonding head 134 has separated the chips 124. As shown in FIG. 11, chips 124a, 124b, 124c, 124d are all fully bonded to the bonding surface 140, and the bonding head 134 has returned to the retracted position. At this point, the bonding process can be repeated with more chips until the fabrication is complete. For example, hundreds or thousands of chips can be bonded to the bonding surface 140.

[0047] After the process of bonding the chips to the bonding surface is completed (which may include many cycles of the bonding method 200, 400 to bond hundreds, thousands, or tens of thousands of chips), the product substrate 138 is removed from the chip bonding section 106, such as by the transfer robot 126. The product substrate may then be subjected to an annealing process (which may include one or both of heat and pressure) where the hybrid bonding process is completed. The product substrate may be subjected to additional processes where additional chips are added to the product substrate before or after the annealing process. The product substrate may then be subjected to additional processes such as singulation, testing, encapsulation, etc., used to manufacture multiple articles from the product substrate.

[0048] It should be noted that not all of the operations described above in the general description or examples are required, some of the specific operations may not be required, and one or more additional operations may be performed in addition to those described. Furthermore, the order in which the operations are listed does not necessarily correspond to the order in which they are performed. Although the above description has been described in the context of a hybrid bonding process, other bonding processes may be used, such as soldering, flip chip bonding, ball grid array bonding, or another process used to form multiple electrical connections between chips.

[0049] Benefits, other advantages, and solutions to problems have been described above with respect to particular implementations. However, the benefits, advantages, solutions to problems, and any features that may give rise to or make more noticeable any benefit, advantage, or solution should not be construed as critical, necessary, or essential features of any or all of the claims.

[0050] The description and illustration of the implementations described herein are intended to give a general understanding of the structure of the various implementations. The specification and drawings are not exhaustive and comprehensive descriptions of all of the elements and features of the apparatus and systems using the structures or methods described herein. Separate implementations may also be provided in combination in a single implementation, and conversely, various features that are described for brevity in the context of a single implementation may also be provided separately or in any subcombination. Furthermore, references to values ​​described in ranges include each and every value within that range. Many other implementations may become apparent to those skilled in the art only after reading this specification. Other embodiments may be used and derived from the present disclosure, such that structural substitutions, logical substitutions, or other changes may be made without departing from the scope of the present disclosure. Thus, the present disclosure should be considered illustrative and not limiting.

Claims

1. 1. A method for bonding chips, comprising: actuating a first bond head to apply a first force to the first tip while the first tip is in contact with a bond surface, thereby partially bonding the first tip to the bond surface; actuating a second bond head to apply a second force to the second tip while the second tip is in contact with the bond surface, thereby partially bonding the second tip to the bond surface; and cooperating with the first bonding head and the second bonding head to apply a third force to the first tip and the second tip to fully bond the first tip and the second tip to the bonding surface. wherein the third force magnitude is greater than the first force magnitude and the second force magnitude.

2. the first force is insufficient to conform the first tip to the mating surface; the second force is insufficient to cause the second tip to conform to the mating surface.

2. The method of claim 1 .

3. 3. The method of claim 2, wherein the third force is sufficient to cause the first tip and the second tip to conform to the mating surface.

4. 2. The method of claim 1, wherein a magnitude of the first force is equal to a magnitude of the second force.

5. 2. The method of claim 1, wherein the magnitude of the first force is different from the magnitude of the second force.

6. 2. The method of claim 1, wherein the first force magnitude and the second force magnitude are each 5-10% of the third force magnitude.

7. bending the first chip before the first chip contacts the bonding surface and before the second chip contacts the bonding surface; bending the second chip before the first chip contacts the bonding surface and before the second chip contacts the bonding surface; 2. The method of claim 1, further comprising:

8. while the first tip remains curved, actuating the first bond head to bring the first tip into contact with the bond surface prior to applying the first force; while the second tip remains curved, actuating the second bond head to bring the second tip into contact with the bond surface before applying the second force; 8. The method of claim 7, further comprising:

9. by actuating the first bonding head to apply the first force to the first tip, a portion of the first tip is partially bonded to the bonding surface while the first tip remains curved; by actuating the second bonding head to apply the second force to the second chip, a portion of the second chip is partially bonded to the bonding surface while the second chip remains curved.

8. The method of claim 7.

10. the portion of the first chip in contact with the bonding surface is a center of the first chip; the portion of the second chip in contact with the bonding surface is a center of the second chip; 10. The method of claim 9.

11. 8. The method of claim 7, further comprising: actuating the first and second bonding heads to apply the third force to the first and second tips, thereby conforming the first and second tips to the bonding surface.

12. The method of claim 11 , wherein the first tip and the second tip are not curved after conforming to the mating surface.

13. coupling the first chip to a first bond head prior to actuating the first bond head to apply the first force and prior to actuating the second bond head to apply the second force; mating the second chip with the second bond head before actuating the first bond head to apply the first force and before actuating the second bond head to apply the second force; 2. The method of claim 1, further comprising:

14. 2. The method of claim 1, wherein the step of actuating the first bond head to apply the first force is performed before the step of actuating the second bond head to apply the second force.

15. 2. The method of claim 1, wherein the step of actuating the second bond head to apply the second force is performed before the step of actuating the first bond head to apply the first force.

16. The method of claim 1 , wherein the bonding surface is a surface of a substrate.

17. The method of claim 1 , wherein the mating surfaces are surfaces of one or more chips.

18. removing the first tip from the first bonding head after the first tip is completely bonded to the bonding surface and after the second tip is completely bonded to the bonding surface; removing the second tip from the second bonding head after the first tip is completely bonded to the bonding surface and after the second tip is completely bonded to the bonding surface; 12. The method of claim 11 further comprising:

19. 1. A system for bonding chips, comprising: A first bonding head; A second joining head; a substrate chuck for holding a substrate having a bonding surface; one or more processors; one or more memories for storing instructions; the instructions, when executed by the one or more processors, cause the system to: actuating a first bond head to apply a first force to the first tip while the first tip is in contact with the bond surface, thereby partially bonding the first tip to the bond surface; actuating a second bond head to apply a second force to the second tip while the second tip is in contact with the bond surface, thereby partially bonding the second tip to the bond surface; and instructions for cooperatively operating the first bond head and the second bond head to apply a third force to the first tip and the second tip to fully bond the first tip and the second tip to the bond surface; The third force is greater than the first force and the second force.

20. 1. A method of manufacturing a plurality of articles, comprising: actuating a first bond head to apply a first force to the first tip while the first tip is in contact with a bond surface, thereby partially bonding the first tip to the bond surface; actuating a second bond head to apply a second force to the second tip while the second tip is in contact with the bond surface, thereby partially bonding the second tip to the bond surface; cooperating with the first bonding head and the second bonding head to apply a third force to the first tip and the second tip to fully bond the first tip and the second tip to the bonding surface, wherein the third force is greater than the first force and the second force; A step of singulating the product substrate to manufacture the plurality of articles; The method according to claim 1, further comprising:

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