WO2025201788A1

WO2025201788A1 - Semiconductor bonding systems and methods

Info

Publication number: WO2025201788A1
Application number: PCT/EP2025/055289
Authority: WO
Inventors: Pieter Willem Herman De Jager; Joost Jeroen Ottens; Victor Sebastiaan DOLK; Jacob Matthias DE KATER; Joep ASSENDELFT; Arjan Johannes Anton BEUKMAN; Syam Parayil VENUGOPALAN; Leslye Astrid UGALDE LOPEZ; Antonius Theodorus Anna Maria Derksen; Marinus Aart Van Den Brink; Sander Christiaan Broers
Original assignee: ASML Netherlands BV
Current assignee: ASML Netherlands BV
Priority date: 2024-03-27
Filing date: 2025-02-27
Publication date: 2025-10-02
Anticipated expiration: 2026-09-27
Also published as: TW202543033A

Abstract

Semiconductor bonding with better placement accuracy and/or higher throughputs compared to prior systems is described. A track comprising a path through a plurality of process stations is used. A plurality of substrate holders are coupled to the track. Each substrate holder is configured to receive and hold a first substrate, and move the first substrate along the path through the plurality of process stations to enable the first substrate to be bonded to a second substrate. A controller is coupled to the track and the plurality of substrate holders. The controller is configured to control relative motion between the plurality of substrate holders to cause each substrate holder to move along the path through the plurality of process stations independently of other substrate holders, with ranges and speeds for each substrate holder that vary according to track position relative to the plurality of process stations.

Description

SEMICONDUCTOR BONDING SYSTEMS AND METHODS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority of EP application 24166691.6 which was filed on March 27, 2024 and which is incorporated herein in its entirety by reference.

TECHNICAL FIELD

[0002] This description relates to semiconductor bonding systems and methods.

BACKGROUND

[0003] In manufacturing processes of integrated circuits (ICs), multiple finished or unfinished ICs (e.g., whole wafers, diced wafers, partially diced wafers, chips, die, etc.) may be placed in contact, stacked, bonded, joined, or otherwise coupled (e.g., to heterogeneous or homogeneous devices) at various points in the fabrication process. The integration of different substrates, circuits, or other patterned devices may rely upon joining of specific portions (for example, conductive contact elements) of multiple die — where these specific portions which may be aligned in three-dimensional space to ensure functional connectivity. As the physical sizes of IC components continue to shrink, and their structures continue to become more complex, accuracy, minimization of distortion and variability, and throughput in coupling become more important. In the context of semiconductor manufacture, improvements in substrate placement and joining lead to improvements in IC manufacturing and integration abilities.

SUMMARY

[0004] Semiconductor bonding with better placement accuracy and/or higher throughputs compared to prior systems is described. According to an embodiment, a semiconductor bonding system is provided. The system includes a track comprising a path through a plurality of process stations. A plurality of substrate holders are coupled to the track. Each substrate holder is configured to receive and hold a first substrate, and move the first substrate along the path through the plurality of process stations to enable the first substrate to be bonded to a second substrate. A controller is coupled to the track and the plurality of substrate holders. The controller is configured to control relative motion between the plurality of substrate holders to cause each substrate holder to move along the path through the plurality of process stations independently of other substrate holders, with ranges and speeds for each substrate holder that vary according to track position relative to the plurality of process stations.

[0005] In some embodiments, each of the first substrates is a die and the second substrate comprises a semiconductor wafer. In some embodiments, the first substrates comprise donor dies. The donor dies may be held by a carrier comprising a wafer foil frame, a reticle shaped carrier, a wafer shaped carrier, individual trays with lids, and/or other carriers. The donor dies may be introduced to the semiconductor bonding system through a front opening universal pod (FOUP) of the system, for example. The carrier may be optically transparent, coated with a photosensitive material, and/or have other characteristics. Each donor die may be coupled to the carrier by something less than a full surface area of a donor die.

[0006] In some embodiments, each of the plurality of substrate holders comprises a chuck configured to receive and hold a first substrate, and move the first substrate along the path through the plurality of process stations to enable the first substrate to be bonded to the second substrate. In some embodiments, each substrate holder is configured to move along the path, and in horizontal, vertical, and/or rotational directions relative to the track via a contactless actuator associated with each substrate holder. In some embodiments, a number of the plurality of substrate holders corresponds to a number of the process stations. For example, a number of the plurality of substrate holders may be equal to the number of process stations. In some embodiments, a number of the plurality of substrate holders is more than a number of the process stations. In some embodiments, a number of the plurality of substrate holders is less than a number of the process stations.

[0007] In some embodiments, each of the plurality of substrate holders, and/or each of the plurality of process stations comprise one or more isolators configured to isolate an environment of the track and the substrate holders from an environment of a process station. An isolator may comprise a gasket, a plate, a suction system, and/or other components.

[0008] In some embodiments, the track comprises a horizontal and/or vertical axis for long stroke movement. In some embodiments, the track comprises two or more parallel processing paths. A parallel processing path is separated from a main path, and associated with at least one of the bonding process stations. For example, the semiconductor bonding system may comprise multiple tracks. The plurality of substrate holders may be configured to be moveable in different directions on the multiple tracks. In some embodiments, the track has an oval shape, an “L” shape, and/or other shapes. In some embodiments, the plurality of substrate holders are configured to move in a continuous closed loop movement, in a clockwise and/or anti-clockwise direction, along the path (e.g., around the oval or “L” shape). In some embodiments, the track comprises a balance mass configured to counteract deformation and/or vibration in the semiconductor bonding system. In some embodiments, the track comprises one or more components configured to cause the plurality of substrate holders to move within a first actuation range, and the plurality of substrate holders comprise one or more components configured to cause the first substrate to move within a second actuation range, shorter than the first actuation range.

[0009] In some embodiments, the track and/or the plurality of substrate holders comprise one or more activation coils, one or more air bearings, a vacuum, a mechanical wheel, a magnetic bearing, a pressure vessel, a sliding bearing, a capacitor, a spring, and/or other components.

[0010] In some embodiments, the system comprises a gripper configured to remove the donor dies from the carrier and couple the donor dies with the plurality of substrate holders, one or more donor dies per substrate holder. The gripper may be and/or include an electrostatic gripper, a vacuum gripper, a gecko gripper, an air bearing gripper, a mechanical gripper, and/or other grippers. In some embodiments, the gripper is configured to grip a donor die based on a reference on the gripper, a location of the reference determined with a camera, interferometrically, via a grid plate, and/or capacitively. In some embodiments, the gripper is configured to grip side surfaces and/or a back surface of a donor die. In some embodiments, the gripper is configured to position a donor die on a mobile substrate holder that is configured to accept the donor die and be placed on the track for further processing.

[0011] In some embodiments, the controller comprises one or more processors, and/or comprises or controls one or more robots, one or more turrets, one or more conveyor belts, one or more drums, and/or other components. In some embodiments, the controller and the plurality of substrate holders are configured such that one or more operations at the plurality of process stations are performed while a given substrate holder is moving. The moving may be controlled in concert with a timing of processing at a process station, for example. In some embodiments, the controller and the plurality of substrate holders are configured such that one or more operations at the plurality of process stations are performed while a given substrate holder is stopped, and others of the plurality of substrate holders are moving.

[0012] In some embodiments, the process stations comprise a bonding station and at least one alignment station, a height and/or rotational adjustment station, a leveling station, a placement station, and/or other stations. In some embodiments, at a bonding station of the plurality of process stations, a given substrate holder is configured to be positioned by the controller with sufficient accuracy and force for bonding to the second substrate; or the given substrate holder is coarsely positioned relative to the second substrate, and the second substrate is moved relative to the given substrate holder with sufficient accuracy and force for bonding. In some embodiments, at an alignment station of the plurality of process stations, a given substrate holder is configured to be positioned by the controller with sufficient accuracy for an alignment measurement by an alignment sensor; or the given substrate holder is coarsely positioned relative to the alignment sensor, and the alignment sensor is moved relative to the given substrate holder with sufficient accuracy for the alignment measurement. In some embodiments, the plurality of process stations comprise a cleaning station configured to clean the first substrates before bonding. In some embodiments, the plurality of process stations comprise an inspection station configured to detect topographic defects in the first substrates before bonding. The inspection station may comprise a dark field imager, a level sensor, a Fourier imager, a capacitive sensor, and/or other components. In some embodiments, the plurality of process stations comprise a leveling station configured to level the first substrates relative to a second substrate before bonding. [0013] According to another embodiment, a coupling method comprising one or more of the operations described above is provided.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The above aspects and other aspects and features will become apparent to those ordinarily skilled in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures.

[0015] Fig. 1 illustrates a typical bonding process flow, according to an embodiment.

[0016] Fig. 2 illustrates a semiconductor bonding system, according to an embodiment.

[0017] Fig. 3 illustrates an example die attachment machine configured to remove each donor die (a first substrate) from a carrier and place each donor die on a substrate holder, according to an embodiment.

[0018] Fig. 4 illustrates different views of an example track of the system, according to an embodiment.

[0019] Fig. 5 illustrates different views of example substrate holders of the system, according to an embodiment.

[0020] Fig. 6 illustrates a balance mass comprising one or more torque compensators that may be included in the system, according to an embodiment.

[0021] Fig. 7 illustrates a semiconductor bonding method, according to an embodiment.

[0022] Fig. 8 is a block diagram of an example computer system, according to an embodiment.

DETAILED DESCRIPTION

[0023] Die stacking is a technique used to obtain more functionality in a semiconductor device - e.g., more transistors in a micro-processor. Bonding of these dies with high lateral placement accuracy in a stack is crucial to guarantee proper matching of electrical contacts across the stack. This is performed using die-to-wafer or wafer-to-wafer bonding tools (or more generally substrate to substrate bonding tools). Existing die-bonding tools can be characterized by their placement accuracy and their throughput expressed as number of die -placements per hour. There are currently no bonding tools that can achieve <100 nm placement accuracy, much less at throughputs required for typical semiconductor manufacturing processes. For example, typical bonding tools perform one substrate to substrate bonding process at a time, usually after one or both substrates has moved sequentially through several separate prior preparatory process stations (e.g., cleaning, alignment, etc.). One or both substrates are typically (manually or mechanically) moved from one station to the next, in a long line of substrates going through these operations, as space in the next operation opens. There is little to no coordination between process steps at the various process stations based on process timing or other factors.

[0024] Advantageously, the present systems and methods facilitate semiconductor bonding with better placement accuracy and/or higher throughputs compared to prior bonding tools. A track comprising a path through a plurality of process stations is used. A plurality of substrate holders are coupled to the track. Each substrate holder is configured to receive and hold a first substrate, and move the first substrate along the path through the plurality of process stations to enable the first substrate to be bonded to a second substrate. A controller is coupled to the track, the plurality of substrate holders, and/or the process stations. The controller is configured to control relative motion between the plurality of substrate holders to cause each substrate holder to move along the path through the plurality of process stations independently of other substrate holders, with ranges and speeds for each substrate holder that vary according to track position relative to the plurality of process stations. This arrangement provides < 100 nm placement accuracy, at throughputs required for typical semiconductor manufacturing processes, among other advantages. Controlling the substrate holders independently from each other allows, for example, precise control of the time spend of each individual substrate at each specific process station. For example the velocity of a first substrate on a first substrate holder subject to an alignment process can then be different from the velocity of a second substrate on a second substrate holder subject to a cleaning operation. As each process step at its corresponding process station may have its own processing time requirements it is beneficial to be able to independently control the speed and range of each substrate holder on the track independently from each other, for example, if it is required to occupy all process stations simultaneously for throughput, productivity, and/or other reasons.

[0025] By way of an introduction, Fig. 1 illustrates a typical bonding process flow 100. In flow 100, a first substrate 104 (e.g., a donor die or wafer) is bonded to a second substrate 110 (e.g., an acceptor die or wafer). This process occurs one bonding process flow 100 at a time, usually after one or both substrates 104 and 110 have moved sequentially through several separate prior preparatory process stations (e.g., cleaning, alignment, etc.). One or both substrates are typically (manually or mechanically) moved from one station to the next, in a long line of substrates going through these operations, as space in the next operation opens (e.g., with little to no coordination between process stations based on process timing or other factors). Fig. 1 illustrates a top chuck 102 holding a top substrate 104, a pin or piston 106, and a bottom chuck 108 holding a bottom substrate 110 throughout several bonding operations of process flow 100. Top chuck 102 and bottom chuck 108 each comprise burls configured to contact a substrate, vacuum channels configured to provide a vacuum force to hold a wafer against the burls, an actuator configured to move the chuck and/or various other components necessary for bonding process flow 100. At operation 120, top substrate 104 is loaded onto top chuck 102. At operation 122, bottom substrate 110 is loaded onto bottom chuck 108. At operation 124, top substrate 104 and bottom substrate 110 are aligned. At operation 126 one and/or both chucks move to establish a specific separation distance between substrates 104 and 110. At operation 128 a bottom vacuum force is established between bottom chuck 108 and bottom substrate 110. At operation 130 a pin or piston 106 is set against top substrate 104. At operation 132 a top chuck inner vacuum force is released so that the center of top substrate 104 is pushed by the pin or piston 106 toward bottom substrate 110. At operation 134, a top chuck outer vacuum force is released so that the outer portions of top substrate 104 are pushed toward bottom substrate 110. At operation 136, the pin or piston force is removed, because top substrate 104 is bonded to bottom substrate 110. [0026] Fig. 2 illustrates a new semiconductor bonding system 200. System 200 provides semiconductor bonding with better placement accuracy and/or higher throughputs compared to prior systems, and/or has other advantages. The system includes a track 202 comprising a path 204 through a plurality of process stations 210-228. A plurality of substrate holders 206 are coupled to the track. A substrate holder 206 may be, or be part of, a shuttle. For example, a shuttle may be formed by a substrate holder 206 plus any other hardware configured to provide movement of the substrate holder 206 and/or keep substrate holder 206 coupled to track 202. Each substrate holder 206 is configured to receive and hold a first substrate 208, and move the first substrate 208 along path 204 through the plurality of process stations 210-228 to enable the first substrate 208 to be bonded to a second substrate 230. In some embodiments, each of the first substrates 208 is a die and second substrate 230 comprises a semiconductor wafer. The semiconductor wafer may comprise additional dies configured to receive the first substrates 208, for example. In some embodiments, the first substrates 208 comprise donor dies, and second substrate 230 comprises an acceptor wafer or acceptor dies.

[0027] In some embodiments, a number of the plurality of substrate holders 206 corresponds to a number of the process stations 210-228. For example, a number of the plurality of substrate holders 206 may be equal to a number of the process stations 210-228. In some embodiments, a number of the plurality of substrate holders 206 is more than a number of the process stations (e.g., as shown in Fig. 2) or less than a number of the processing stations 210-228. In some embodiments, a single first substrate 208 is held by a single substrate holder 206. However, in some embodiments, two or more first substrates 208 may be held and moved through the process stations by a substrate holder 206. [0028] In Fig. 2, bonding occurs at bonding station 228, where each first substrate 208 is transferred 232 from a substrate holder 206 to a second substrate 230 (which is held by a chuck 234 in this example). This occurs in sequence as the substrate holders 206 move around track 202. As several examples, the process stations may include an initial inspection station 210, a course placement station 212, a cleaning station 214, a plasma treating station 216, a topographic inspection station 218, a leveling station 220, a coarse alignment station 222, a position adjustment station 224 (e.g., where an x, y, z, and/or rotational position of each first substrate 208 may be adjusted), a fine alignment station 226, a bonding station 228, and/or other stations. Note that there may be more or less stations in system 200 than those shown in Fig. 2. [0029] For example, in some embodiments, the process stations comprise a bonding station 228 and at least one alignment station 226 and/or 222, a height and/or rotational adjustment station 224, a leveling station 220, a placement station 212, and/or other stations. In some embodiments, at bonding station 228 of the plurality of process stations 210-228, a given substrate holder 206 is configured to be positioned by a controller 250 (described below) with sufficient accuracy and force for bonding to a second substrate 230; or the given substrate holder 206 is coarsely positioned relative to second substrate 230, and second substrate 230 is moved relative to the given substrate holder 206 with sufficient accuracy and force for bonding. In some embodiments, at an alignment station 226 and/or 224 of the plurality of process stations, a given substrate holder 206 is configured to be positioned by controller 250 with sufficient accuracy for an alignment measurement by an alignment sensor; or the given substrate holder 206 is coarsely positioned relative to the alignment sensor, and the alignment sensor is moved relative to the given substrate holder 206 with sufficient accuracy for the alignment measurement.

[0030] By way of several additional examples, at initial inspection station 210, first substrates 208 (e.g., dies) are rejected when, e.g., particles are found on a surface that prohibits proper bonding or when a first substrate 208 cannot be aligned properly. A gripper (similar to and/or the same as machine 300 illustrated in Fig. 3 and described below) may be used to remove a rejected first substrate 208 from a substrate holder. Rejected first substrates 208 may be placed on a carrier such as wafer foil frame to enable rework, placed in a waste bin, and/or placed in other locations. In some embodiments, first substrates 208 that are rejected based on particles may make a second round on track 202 to create a second opportunity to use a first substrate 208 after cleaning (e.g., as described below). In some embodiments, first substrates 208 that are rejected based on alignment sensor and/or level sensor information (e.g., as described below) may make a second round on track 202 to create a second opportunity to use the first substrate 208. In some embodiments, the number of dies that are placed in the waste bin (e.g., a wafer foil frame) versus the capacity of the waste bin may be tracked such that a wafer foil frame handler can remove it when full.

[0031] In some embodiments, cleaning station 214 is configured to clean the first substrates 208 before bonding (e.g., using CO2 snow cleaning - https://www.youtube.com/watch?v=XDkkeSINtNw - as one possible example). Another cleaning method may use a high intensity laser beam such that particles are heated/baked/lifted off (preferably using a laser wavelength a die is not sensitive to), and/or use a razor knife to “scrape” particles from the surface of a first substrate 208 (e.g., a donor die). Another way to clean a first substrate 208 (e.g., a die or a wafer) is to remove an oxide layer either using a plasma or using chemicals. Lifting off the oxide layer takes any particles with it. This list of cleaning methods is not exhaustive.

[0032] In some embodiments, inspection station 218 is configured to detect topographic defects in the first substrates 208 before bonding. Topographic inspection looks for particles or indents on a bonding surface of a first substrate 208 (e.g., a donor die). These have a negative impact on bonding as they often result in voids. In-line inspection for topographic defects (e.g., particles or indents) is beneficial for yield. Substrates with defects are either rejected or may go through another cleaning step, for example. In some embodiments, inspection station 218 may comprise a dark field imager, a level sensor, a Fourier imager, a capacitive sensor, a combination of these components, and/or other components. For example, topographic inspection can be realized by a dark field imager. A die (first substrate 208) may be illuminated at a shallow angle and diffracted/reflected light is analyzed. An amount of diffracted light is an indication of defects. The sensitivity for small particles can be enhanced by using a short wavelength light source, e.g., deep ultra violet (DUV) and/or soft X-ray, for example. In capacitive sensing, the donor die is used as one electrode. When another electrode is in close proximity of the donor die surface, a particle on the die will influence the capacity.

[0033] In some embodiments, leveling station 220 is configured to level the first substrates 208 before bonding. Leveling station 220 may be configured to measure the height of a first substrate 208 (e.g., a donor die) on at least three points of a first substrate 208 to determine the height (Z), x- dimension rotation (Rx) and y-dimension rotation (Ry) of a first substrate 208. In some embodiments, leveling station 220 may include a half-dome die-table, and be configured to unlock its movement, use an airfoot to level a first substrate 208, and lock the half-dome. In some embodiments, confocal microscopy may be used for die leveling (array in parallel). The required optics can be very small. In some embodiments, an interferometer may be used to measure only at places of interest on a first substrate 208 - e.g., where alignment marks are located. In some embodiments, an ultrasonic level sensor may be used, with time of flight as a measurement of distance between a transducer and first substrate 208. In some embodiments, an air gauge may be used as level sensor, mirror electron microscopy may be used to flood a first substrate 208 with an exposure of electrons and observe potential lines at a detector, capacitive sensing may be used as level sensor, and or other sensors may be used. In some embodiments, an optical level sensor that is part of leveling station 220 may comprise a dark field camera such that level sensing may be combined with topographic inspection in system 200.

[0034] At position adjustment station 224, X, Y, Z, and/or R(x,y,z) position adjustments occur that use coarse alignment information, the position of a substrate holder 206 relative to fixed machine coordinates of system 200, and/or other information to position a first substrate 208 (e.g., a donor die) prior to fine alignment with about lOOnm accuracy. Correction of Rz position may be performed to limit the rotation activation of second substrate 230 (e.g., the acceptor wafer) during eventual die bonding, for example. Track 202 may be used to move a substrate holder 206 in X, Y, Z, Rx, Ry and Rz using a six coil-magnet combination and/or other components, for example. In this way a maglev stage may be created with six degrees of freedom (see Fig. 4, Fig. 5, and related paragraphs for additional description of these degrees of freedom). In some embodiments, sensors 260 (described herein) such as accelerometers on track 202 may be used for better attenuation of vibrations induced by disturbance forces, resulting in higher accuracy. Alternatively, track 202 may facilitate coarse motion of a substrate holder 206, and additional mechanisms on a substrate holder 206 function as short stroke stage (as described herein). Information about any required adjustments may also come from the leveling and coarse alignment process stations, for example.

[0035] In some embodiments, the plurality of substrate holders, and/or one or more of the plurality of process stations comprise one or more isolators 298 (see example dashed lines in Fig. 2) configured to isolate an environment of track 202 and substrate holders 206 from and environment of a process station 210-228. An isolator 298 may comprise a gasket, a plate, a suction system, a gas flow, and/or other components, for example.

[0036] A controller 250 is operatively coupled to track 202, the plurality of substrate holders 206, and/or other components of system 200. Controller 250 is configured to control relative motion between the plurality of substrate holders 206 to cause each substrate holder 206 to move along path 204 through the plurality of process stations 210-228 independently of other substrate holders 206, with ranges and speeds for each substrate holder 206 that vary according to track 202 position relative to the plurality of process stations 210-228. Controller 250 may be configured to control substrate holders 206, the process stations 210-228, and/or other components of system 200 based on output signals from track 202, substrate holders 206, and/or process stations 210-228, and/or other information. For example, Fig. 2 illustrates a few representative example position and/or motion sensors 260 on track 202 and/or substrate holders 206, and representative example process sensors 262 at some of the process stations 210-228. These are representative examples only (i.e., a motion sensor 260 and/or a process sensor 262 may not be shown in a certain location in Fig. 2 for space saving reasons, even though there may be many more sensors 260 associated with substrate holders 206 and/or track 202, and many more sensors 262 may be associated with each process station 210- 228). These and/or other sensors may generate any number and/or type of output signals that may be used by controller 250 to control system 200. Controller 250 is configured to generate one or more control signals for controlling various components of system 200 based on these (feedback) signals, and/or other information. Control by controller 250 may include adjustments made based on positions of various substrate holders 206 on track 202; speeds of substrate holders; timing requirements for individual processing stations 210-228; acceleration of substrate holders; jerk, snap, crackle, and/or pop of substrate holders; and/or other information, for example. The controlling may be performed with one or more processors and/or other components of controller 250 (see Fig. 8 and computer system CS described below for further explanation related to the one or more processors). In some embodiments, controller 250, substrate holders 206, track 202, and/or other components of system 200 comprise a transmitter and/or other components configured to transmit and/or receive signals to and/or from controller 250 to cause system 200 to operate as described herein. [0037] In some embodiments, controller 250 comprises one or more processors, one or more robots, one or more turrets, one or more conveyor belts, one or more drums, and/or other components. For example, in some embodiments, one or more processors of controller 250 may control multiple robots, turrets, conveyor belts, and/or drums, with an operating speed of each one can be individually controlled. As another example, controller 250 may control a single robot, turret, conveyor belt, and/or drum, moving at a constant speed, such that substrate holders 206 move along track 202 in unison. In some embodiments, substrate holders 206 may be controlled to move at different speeds in different portions of track 202. In some embodiments, controller 250 and the plurality of substrate holders 206 are configured such that one or more operations at the plurality of process stations 210- 228 are performed while a given substrate holder 206 is moving. The moving may be controlled in concert with a timing of processing at a process station, for example. In some embodiments, controller 250 and the plurality of substrate holders 206 are configured such that one or more operations at the plurality of process stations 210-228 are performed while a given substrate holder 206 is stopped (e.g., does not move with respect to a process station), and others of the plurality of substrate holders 206 are moving (with respect to the process station). For example, controller 250 may be configured to optimize movements of substrate holders 206 throughout the process stations 210-228 of system 200 to enhance throughput, and/or for other reasons. This optimization may be based on the process time required at each individual process station 210-228, and/or other information.

[0038] In some embodiments, controller 250 and/or other components of system 200 communicate unidirectionally and/or bidirectionally with each other and/or other devices such as mobile user devices, a desk-top user device, external resources such as a server, and/or other devices. Each of these devices may communicate wirelessly and/or via wires. For example, each of these devices may communicate via a network, such as the Internet or the Internet in combination with various other networks, like local area networks, cellular networks, Wi-Fi networks, or personal area networks. [0039] Mobile user devices may be smart phones, tablets, or other hand-held networked computing devices having a display, a user input device (e.g., buttons, keys, voice recognition, or a single or multi-touch touchscreen), memory (such as a tangible, machine -readable, non-volatile memory), a network interface, a portable energy source (e.g., a battery), and a processor (a term which, as used herein, includes one or more processors) coupled to each of these components. The memory of mobile user devices may store instructions that when executed by the associated processor provide an operating system and various applications, including a web browser or a native mobile application. A desktop user device may also include a web browser, for example. In addition, a desktop user device may include a monitor; a keyboard; a mouse; memory; a processor; and a tangible, non-transitory, machine -readable memory storing instructions that when executed by the processor provide an operating system and the web browser. Native applications and web browsers, in some embodiments, are operative to provide a graphical user interface associated with a user, for example, that communicates with controller 250 and/or other components of system 200 and facilitates user interaction with data from system 200.

[0040] External resources, in some embodiments, include sources of information such as databases, websites, etc.; external entities participating with system 200; one or more servers outside of the system 200; a network (e.g., the internet); electronic storage; equipment related to Wi-Fi ™ technology; equipment related to Bluetooth® technology; data entry devices; or other resources. In some implementations, some or all of the functionality attributed herein to external resources may be provided by resources included in system 200. External resources may be configured to communicate with one or more components of system 200 via wired and/or wireless connections, via a network (e.g., a local area network and/or the internet), via cellular technology, via Wi-Fi technology, and/or via other resources.

[0041] As described above, in some embodiments, each of the first substrates 208 is a die and the second substrate 230 comprises a semiconductor wafer. In some embodiments, the first substrates 208 comprise donor dies. The donor dies may initially be held by a carrier 275 (shown in Fig. 2 with and without donor dies) comprising a wafer foil frame (e.g., with a diameter larger than a wafer), a reticle shaped carrier, a wafer shaped carrier, individual trays with lids, and/or other carriers. The donor dies may be introduced to the semiconductor bonding system through a front opening universal pod (FOUP) 280 of the system, for example. Fig. 2 illustrates FOUP 280 comprising a FOUP for a donor substrate and optionally a foil frame, and a second FOUP 282 for a foil frame. The carrier 275 may be optically transparent (e.g., made of glass or similar material), coated with a photosensitive material (e.g., to help overcome forces during picking of a die from carrier 275 and placement of a die of a substrate holder 206), and/or have other characteristics. Each donor die may be coupled to the carrier by something less than a full surface area of a donor die (e.g., to make it easier to remove from the carrier by a gripper), for example. This may be done to minimize bonding forces and/or for other reasons. The donor dies and the carrier 275 may be transported to the first processing station (e.g., 210) using any appropriate mechanical transportation means, for example.

[0042] Once at or near (or on the way to) the first processing station (e.g., initial inspection station 210, or course placement station 212), each donor die (first substrate 208) may be removed from carrier 275 and placed on a substrate holder 206. Fig. 3 illustrates an example die attachment machine 300 configured to remove each donor die (first substrate 208) from carrier 275 and place each donor die on a substrate holder 206. As shown in Fig. 3, machine 300 moves back and forth between carrier 275 and each successive substrate holder 206, placing one donor die (first substrate 208) per substrate holder. Note that in some embodiments, machine 300 may place more than one donor die on each substrate holder for processing. Machine 300 may pick up adjacent dies from carrier 275, dies from opposite sides of carrier 275 with each successive pick up, and/or may pick up dies in other patterns. The dies can be transferred from carrier 275 to substrate holder 206 such that they are clamped to substrate holder 206 on the same side that was connected to carrier 275. Alternatively they can be flipped during transfer from carrier 275 to substrate holder 206. In some embodiments, carrier 275 may be coupled to a two dimensional stage controlled by controller 250 (Fig. 2) to move carrier 275 closer to substrate holders 206 to minimize the distance between carrier 275 and substrate holders 206 for transfer.

[0043] Releasing a donor die from carrier 275 may be realized by (1) peeling a die off carrier 275 starting at one side or corner of a die, (2) heating carrier 275 locally such that carrier glue releases, (3) exposing carrier 275 from the backside with light that causes glue release, and/or by other methods. As described herein, donor dies can be transferred from the carrier to a substrate holder 206 one-by- one, with a single donor die per substrate holder 206. Alternatively multiple dies may be placed on one substrate holder 206 so that multiple dies are processed in parallel.

[0044] Machine 300 may include one or more robotic arms, grippers, various motors, and/or other components that allow machine 300 to operate as described herein. For example, in some embodiments, machine 300 comprises a gripper configured to remove the donor dies from carrier 275 and couple the donor dies with the plurality of substrate holders 206, one donor die per substrate holder. The gripper may be and/or include an electrostatic gripper, a vacuum gripper, a gecko gripper, an air bearing gripper, a mechanical gripper, and/or other grippers. In some embodiments, the gripper is configured to grip a donor die based on a reference on the gripper, a location of the reference determined with a camera, interferometrically, via a grid plate, capacitively, and/or by other methods. For example, alignment of a donor die to a substrate holder 206 (Fig. 2) can be camera based on the position of the edge of the die. Alternatively, the die may be configured to be mechanically self-aligning to a substrate holder 206 by means of, for example, a pocket or recess with limited depth in the substrate holder 206 with a size substantially equal to (or just larger than) the size of the donor die. As another example, a three -ball/groove docking interface may be used by the gripper, substrate holder 206, and carrier 275 to meet (e.g., ten micron) accuracy requirements. In general, if one positions an object using three balls on an object and three grooves on a floor the positioning is not overdetermined and hence has the highest possible reproducibility. Typically the position of the balls and grooves is done around the thermal center of both objects thereby eliminating thermal difference effects.

[0045] The gripper (machine 300), donor die (first substrate 208), and substrate holder 206 are measured and positioned with respect to the fixed machine coordinate system of system 200 (Fig. 2). The fixed machine coordinate system is common to the gripper, donor die, and substrate holder 206. Output signals from a motion sensor 260 and/or a process sensor 262 (e.g., see Fig. 2, as described above) at course placement station 212 (Fig. 2), for example, may be used to determine three dimensional (3D) coordinates of the gripper, the donor die, and the substrate holder 206. System 200 may comprise a reference configured to serve as a point (or points) of reference for the sensors and/or a gripper’s interface with the donor die (the 3 ball - groove for example), ensure the donor die is reproducibly transported by the gripper, and ensure the donor die is reproducibly accepted by the substrate holder 206. In some embodiments, the reference and interface may comprise a camera based measurement system that grabs the donor die edges and the gripper contact points in one frame and uses that as position control input.

[0046] In some embodiments, the gripper is configured to grip side surfaces and/or a back surface of a donor die. For example, the gripper may have minimal mechanical contact with the front side of the donor dies, as this can be plasma activated to facilitate bonding. In some embodiments, the gripper may be configured for touching the donor dies along one or two narrow slits that are near the edges of the die, for example. In some embodiments, an air bearing gripper may be used. Here, a central area of the gripper is evacuated (placed under vacuum) while an edge comprises nozzles with over-pressure XCDA air. In this way, there is no mechanical contact with a donor die surface. To prevent a donor die from sliding away from the gripper mechanical arms and/or other structures can be used to limit lateral motion. In some embodiments, an opposite dome shaped gripper may be used for supporting various die sizes and may be compatible with a dome shaped clamp configured for defining a starting point of bonding to an acceptor wafer.

[0047] In some embodiments, the gripper is configured to position a donor die on a mobile substrate holder 206 that is configured to accept the donor die and be placed on the track (see Fig. 2) for further processing. To enhance throughput, the gripper may receive information (from controller 250) about substrate holder 206 position. In this way the gripper can accurately position the donor die before the substrate holder 206 has come to full stop, or even accurately position the donor die “on the fly” (while substrate holder 206 is moving).

[0048] Productivity (throughput at high accuracy) is a key parameter of machine 300 (and/or other parts of system 200) to make it commercially viable. Productivity is given by the speed in which an individual donor die can be contacted on a substrate holder 206, and subsequently bonded to second substrate 230 (Fig. 2). This speed is limited by the allowable stress (required contact time) during the contacting process, Tc. The maximum productivity is given by n*Tc where n equals to the number of dies being transferred. In some embodiments, m die handling machines 300 (e.g., robots) may be used which need Td time to catch a die and move this die to an acceptor location. The maximum productivity is given Max(n*Tc, (m/n)*Td). Very likely given the distance to be travelled by machine 300, Td>Tc. To not substantially decrease productivity, m machines 300 are needed such that m > Td/Tc. Given an practical layout of system 200, there may be > 10 machines 300, for example.

[0049] Returning to Fig. 2, in some embodiments, second substrate 230 may be an acceptor substrate, such as an acceptor or acceptor wafer, for example. Fig. 2 also illustrates a FOUP for second substrate 230 before (an acceptor FOUP 285) and after bonding (a bonded wafer FOUP 290 for second substrate once first substrate(s) 208 have been bonded to second substrate(s) 230). Second substrate 230 may be transported to the bonding station, and the after bonding version of second substrate 230 (which includes first substrate(s) 208) may be transported back to bonded FOUP 290 using any appropriate mechanical transportation means, for example.

[0050] In some embodiments, each of the plurality of substrate holders 206 comprises a chuck configured to receive and hold a first substrate 208, and move the first substrate 208 along path 204 through the plurality of process stations 210-228 to enable the first substrate 208 to be bonded to the second substrate 230. In some embodiments, each substrate holder 206 is configured to move along path 204, and in horizontal, vertical, and/or rotational directions relative to track 202 via one or more actuators associated with each substrate holder 206 and/or other components.

[0051] For example, Fig. 4 and Fig. 5 illustrate different views of an example track 202 and substrate holders 206. As one practical example, a track 202 such as one produced by Supertrak (https://supertrakconveyance.com/) where wheels are used to guide substrate holders 206 may be used in system 200. As shown in Fig. 5, each of the plurality of substrate holders 206 comprises a chuck 500 configured to receive and hold a first substrate 208 (see Fig. 2), and move the first substrate 208 along track 202 (Fig. 4, Fig. 2). In some embodiments, each substrate holder 206 is configured to move along track 202, and in horizontal 410, vertical 420, and/or rotational 430 directions (Fig. 4) relative to track 202 via one or more actuators 550 (Fig. 5) associated with each substrate holder 206 and/or other components. Note that horizontal 410 and vertical 420 directions (Fig. 4) are labeled according to the orientation shown in Fig. 4, but in Fig. 2, each of these may be rotated by ninety degrees, for example. In some embodiments, track 202 and/or the plurality of substrate holders 206 comprise one or more actuators such as contactless actuators, activation coils, one or more air bearings, a vacuum, a mechanical wheel, a magnetic bearing, a pressure vessel, a sliding bearing, a capacitor, a spring, a motor, a rotating stage, and/or other components. Fig. 5 illustrates several of these examples, including mechanical wheels 560, air 570 / vacuum 580 based actuators, and a magnetic bearing 590. In some embodiments, substrate holders 206 may have one degree of freedom control around track 202. In some embodiments, each substrate holder 206 may include a contactless six degree of freedom mini-stage (e.g., Lorentz controlled as one example), used to position a first substrate 208 (Fig. 2) with nanometer accuracy for bonding, and/or other operations shown in Fig. 2. In this way, vibrations and/or other unwanted forces are not transferred from adjacent substrate(s) (holders) or any other components coupled to the track 202 to a first substrate 208, among other advantages, for example.

[0052] In some embodiments, substrate holder 206 motion can be realized by a hexapod on or within a shuttle associated with substrate holder 206 activated by electrically controlled actuators, for example piezoelectric and/or Lorentz actuators, and/or other components. In some embodiments, there may be a brake on the chuck of a substrate holder 206 at each process station. The brake may be relaxed and the chuck adjusted using coils and magnets on a substrate holder 206, for example. An embodiment of a substrate holder and/or shuttle may comprise three folded leaf springs at 120 degree angles around a central axis, and/or other components. This enables X, Y, and/or Rz motion of the substrate holder 206 (chuck). For long stroke Z-motion as needed for bonding and/or other operations, the central axis can be moved by way of three double-leaf springs, for example.

[0053] In some embodiments, each substrate holder 206 comprises burls configured to contact first substrate 208, a plurality of vacuum channels coupled to a vacuum (not shown in Fig. 4 or 5) configured to provide a vacuum force to hold first substrate 208 against the burls, an actuator and/or other components (e.g., as described above) configured to move each substrate holder 206, and/or other components. In some embodiments, system 200 comprises a second substrate holder comprising chuck 234 (Fig. 2) and/or other similar components configured to hold second substrate 230 (Fig. 2). The second substrate holder may comprise additional burls configured to contact second substrate 230, and a second plurality of vacuum channels (not shown in Fig. 4 or 5) configured to provide a second vacuum force to hold second substrate 230 against the burls.

[0054] Returning to Fig. 2, in some embodiments, track 202 comprises one or more components (e.g., actuators, activation coils, one or more air bearings, a mechanical wheel, a magnetic bearing, a sliding bearing, a capacitor, a spring, a motor, and/or other components described above) configured to cause the plurality of substrate holders 206 to move within a first actuation range. This first actuation range may be a long stroke actuation range, for example. In some embodiments, track 202 comprises a horizontal 270 and/or vertical 272 axis (again noting that horizontal 270 and vertical 272 are labeled according to the orientation shown in Fig. 2, but in Fig. 4, each of these may be rotated by ninety degrees) for long stroke movement. Long stroke movement may comprise movements on the order of centimeters, or meters, for example. The plurality of substrate holders 206 and/or shuttles comprise one or more components (e.g., the contactless actuators, activation coils, one or more air bearings, vacuum, mechanical wheel, magnetic bearing, pressure vessel, sliding bearing, capacitor, spring, motor, rotating stage, and/or other components described above) configured to hold first substrate 208 and cause first substrate 208 to move within a second actuation range, shorter than the first actuation range. The second actuation range may be a short stroke actuation range, for example. Short stroke movement may comprise movements on the order of millimeters, micrometers, and/or nanometers, for example.

[0055] In some embodiments, track 202 comprises two or more parallel processing paths 274. A parallel processing path 274 is separated from a main path, and associated with at least one of the bonding process stations 210-228. For example, the semiconductor bonding system may comprise multiple tracks 202. The plurality of substrate holders 206 may be configured to be moveable in different directions on the multiple tracks 202. In Fig. 2, parallel processing path 274 (and the track that defines it) skip processing operations 214 (cleaning), 216 (plasma treatment), and 218 (topographic inspection). Track 202 may include one or more straight sections, one or more curved sections, and/or other sections. In some embodiments, track 202 has an oval shape (e.g., as shown in Fig. 2, and in Fig. 4), an “L” shape, and/or other shapes. In some embodiments, the plurality of substrate holders 206 are configured to move in a continuous closed loop movement, in a clockwise and/or anti-clockwise direction, along track 202 / path 204 (e.g., around the oval or “L” shape). In some embodiments track 202 may be gas or liquid cooled, and/or have other temperature control systems.

[0056] In some embodiments, track 202 comprises a balance mass configured to counteract deformation and/or vibration in semiconductor bonding system 200. For example, as shown in Fig. 6, system 200 may include a balance mass 650 comprising one or more torque compensators T. There are two torque compensators T in this example. The torque compensators T may comprise a motor with a rotating dummy mass (as in this example) and/or other components. As indicated by the arrows in Fig. 6, the plurality of substrate holders 206 and first substrates 208 move in a clockwise direction around track 202. Torque compensators T rotate in the opposite direction. By adding one or more torque compensators T (e.g., the motors with rotating dummy masses), the reaction torque on a base frame 652 of system 200 can be counteracted and/or at least greatly reduced. As another option, by not moving all substrate holders 206 at the same time, the reaction torque (peak) on base frame 652 can also be greatly reduced. These are just two of many possible options. Overall, counteracting forces with a balance mass is configured to minimize the deformation and vibrations of the base frame 652. If, as in some embodiments, all substrate holders 206 do move in one direction, the forces cause a torque on base frame 652. The torque needed to accelerate the rotating dummy mass can counteract the torque from the moving substrate holders 206.

[0057] Fig. 7 illustrates a semiconductor bonding method 700. Fig. 7 illustrates a sequence of actions, none limiting, describing semiconductor bonding. In some embodiments, one or more operations of method 700 may be implemented in or by a system described above, a computer system (e.g., as illustrated in Fig. 8 and described below), and/or in or by other systems, for example. In some embodiments, method 700 comprises receiving and holding (course placement operation 702) a first substrate (e.g., a donor die or a donor wafer) so that it can eventually be bonded to a second substrate. A plurality of first substrates are each received and held by a plurality of corresponding substrate holders coupled to a track. The first substrates are moved along a path through a plurality of process stations to enable the first substrates to be bonded to one or more second substrates. Method 700 includes cleaning (operation 704) the first substrates, plasma treating (operation 706) the first substrates, inspecting (topographic inspection operation 708) the first substrates, leveling (operation 710) the first substrates, coarsely aligning (operation 712) the first substrates, adjusting a position (x, y, z, Rz adjustment operation 714) of the first substrates, finely aligning (operation 716) the first substrates, bonding (operation 718) the first substrates to one or more second substrates (e.g., an acceptor die and/or an acceptor wafer), rejecting (operation 720) a first substrate and/or a bonded first and second substrate if process specifications are not met, and/or other operations.

[0058] The operations of method 700 may be performed along a track comprising a path through a plurality of process stations. A plurality of substrate holders are coupled to the track. Each substrate holder is configured to receive and hold a first substrate, and move the first substrate along the path through the plurality of process stations to enable the first substrate to be bonded to a second substrate, as described above. A controller is coupled to the track and the plurality of substrate holders. The controller is configured to control relative motion between the plurality of substrate holders to cause each substrate holder to move along the path through the plurality of process stations independently of other substrate holders, with ranges and speeds for each substrate holder that vary according to track position relative to the plurality of process stations.

[0059] In some embodiments, each of the first substrates is a die and the second substrate comprises a semiconductor wafer. In some embodiments, the first substrates comprise donor dies. The donor dies may be held by a carrier comprising a wafer foil frame, a reticle shaped carrier, a wafer shaped carrier, individual trays with lids, and/or other carriers. The donor dies may be introduced to the semiconductor bonding system through a front opening universal pod (FOUP) of the system, for example (e.g., at operation 702). The carrier may be optically transparent, coated with a photosensitive material, and/or have other characteristics. Each donor die may be coupled to the carrier by something less than a full surface area of a donor die.

[0060] In some embodiments, each of the plurality of substrate holders comprises a chuck configured to receive and hold a first substrate, and move the first substrate along the path through the plurality of process stations to enable the first substrate to be bonded to the second substrate. In some embodiments, each substrate holder is configured to move along the path, and in horizontal, vertical, and/or rotational directions relative to the track via a contactless actuator associated with each substrate holder. In some embodiments, a number of the plurality of substrate holders corresponds to a number of the process stations. In some embodiments, a number of the plurality of substrate holders is more than a number of the process stations.

[0061] In some embodiments, a portion of one or more of operations 702-720 may include isolating an environment of the track and the substrate holders from an environment of a process station. For example, each of the plurality of substrate holders, and/or each of the plurality of process stations may comprise one or more isolators configured to isolate an environment. An isolator may comprise a gasket, a plate, a suction system, and/or other components.

[0062] In some embodiments, the track comprises a horizontal and/or vertical axis for long stroke movement. In some embodiments, the track comprises two or more parallel processing paths. A parallel processing path is separated from a main path, and associated with at least one of the bonding process stations. For example, the semiconductor bonding system may comprise multiple tracks. The plurality of substrate holders may be configured to be moveable in different directions on the multiple tracks. In some embodiments, the track has an oval shape, an “L” shape, and/or other shapes. In some embodiments, the plurality of substrate holders are configured to move in a continuous closed loop movement, in a clockwise and/or anti-clockwise direction, along the path (e.g., around the oval or “L” shape). In some embodiments, the track comprises a balance mass configured to counteract deformation and/or vibration in the semiconductor bonding system. In some embodiments, the track comprises one or more components configured to cause the plurality of substrate holders to move within a first actuation range, and the plurality of substrate holders comprise one or more components configured to cause the first substrate to move within a second actuation range, shorter than the first actuation range. In some embodiments, the track and/or the plurality of substrate holders comprise one or more activation coils, one or more air bearings, a vacuum, a mechanical wheel, a magnetic bearing, a pressure vessel, a sliding bearing, a capacitor, a spring, and/or other components.

[0063] In some embodiments, operation 702 comprises removing donor dies from a carrier and coupling the donor dies with the plurality of substrate holders, one donor die per substrate holder. This may be performed by a gripper, and/or other components. The gripper may be and/or include an electrostatic gripper, a vacuum gripper, a gecko gripper, an air bearing gripper, a mechanical gripper, and/or other grippers. In some embodiments, the gripper is configured to grip a donor die based on a reference on the gripper, a location of the reference determined with a camera, interferometrically, via a grid plate, and/or capacitively. In some embodiments, the gripper is configured to grip side surfaces and/or a back surface of a donor die. In some embodiments, the gripper is configured to position a donor die on a mobile substrate holder that is configured to accept the donor die and be placed on the track for further processing.

[0064] In some embodiments, the controller comprises one or more processors, one or more robots, one or more turrets, one or more conveyor belts, and/or one or more drums. In some embodiments, the controller and the plurality of substrate holders are configured such that one or more operations at the plurality of process stations are performed while a given substrate holder is moving. The moving may be controlled in concert with a timing of processing at a process station, for example. In some embodiments, the controller and the plurality of substrate holders are configured such that one or more operations at the plurality of process stations are performed while a given substrate holder is stopped, and others of the plurality of substrate holders are moving.

[0065] As a small number of representative examples, in some embodiments, the process stations comprise a bonding station and at least one alignment station, a height and/or rotational adjustment station, a leveling station, a placement station, and/or other stations. In some embodiments, at a bonding station of the plurality of process stations (i.e., at operation 718), a given substrate holder is configured to be positioned by the controller with sufficient accuracy and force for bonding to the second substrate; or the given substrate holder is coarsely positioned relative to the second substrate, and the second substrate is moved relative to the given substrate holder with sufficient accuracy and force for bonding. In some embodiments, at an alignment station of the plurality of process stations (i.e., at operation 716 and/or 712), a given substrate holder is configured to be positioned by the controller with sufficient accuracy for an alignment measurement by an alignment sensor; or the given substrate holder is coarsely positioned relative to the alignment sensor, and the alignment sensor is moved relative to the given substrate holder with sufficient accuracy for the alignment measurement. In some embodiments, the plurality of process stations may comprise a cleaning station configured to clean (i.e., operation 704) the first substrates before bonding. In some embodiments, the plurality of process stations comprise an inspection station configured to detect (i.e., operation 708) topographic defects in the first substrates before bonding. The inspection station comprises a dark field imager, a level sensor, a Fourier imager, a capacitive sensor, and/or other components. In some embodiments, the plurality of process stations comprise a leveling station configured to level the first substrates before bonding.

[0066] The operations of method 700 are intended to be illustrative. In some embodiments, method 700 may be accomplished with one or more additional operations not described, and/or without one or more of the operations discussed. Additionally, the order in which the operations of method 700 are illustrated in Fig. 7 and described herein is not intended to be limiting.

[0067] In some embodiments, one or more portions of method 700 may be implemented in and/or controlled by one or more processing devices (e.g., a digital processor, an analog processor, a digital circuit designed to process information, an analog circuit designed to process information, a state machine, and/or other mechanisms for electronically processing information). The processing devices may be or be included in a computer system such as a desktop computer, a laptop computer, a smartphone, a server, and/or other computing devices, for example. The one or more processing devices may include one or more devices executing some or all of the operations of method 700 in response to instructions stored electronically on an electronic storage medium. The one or more processing devices may include one or more devices configured through hardware, firmware, and/or software to be specifically designed for execution of one or more of the operations of method 700. [0068] Fig. 8 is a diagram of an example computer system CS that may be used for one or more of the operations described herein (e.g., one or more of the operations of method 700 shown in Fig. 7 and/or other operations). Computer system CS may be included in and/or be similar to and/or the same as the controller described above (e.g., computer system CS may form some or all of the controller described above). Computer system CS includes a bus BS or other communication mechanism for communicating information, and a processor PRO (or multiple processors) coupled with bus BS for processing information. Computer system CS also includes a main memory MM, such as a random access memory (RAM) or other dynamic storage device, coupled to bus BS for storing information and instructions to be executed by processor PRO. Main memory MM also may be used for storing temporary variables or other intermediate information during execution of instructions by processor PRO. Computer system CS further includes a read only memory (ROM) ROM or other static storage device coupled to bus BS for storing static information and instructions for processor PRO. A storage device SD, such as a magnetic disk or optical disk, is provided and coupled to bus BS for storing information and instructions.

[0069] Computer system CS may be coupled via bus BS to a display DS, such as a flat panel or touch panel display for displaying information to a computer user or observer. An input device ID, including alphanumeric and other keys, is coupled to bus BS for communicating information and command selections to processor PRO. Another type of user input device is cursor control CC, such as a mouse, a trackball, or cursor direction keys for communicating direction information and command selections to processor PRO and for controlling cursor movement on display DS. This input device typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y), that allows the device to specify positions in a plane. A touch panel (screen) display may also be used as an input device.

[0070] In some embodiments, all or some of one or more operations described herein may be performed by computer system CS in response to processor PRO executing one or more sequences of one or more instructions contained in main memory MM. Such instructions may be read into main memory MM from another computer-readable medium, such as storage device SD. Execution of the sequences of instructions included in main memory MM causes processor PRO to perform the process steps (operations) described herein. One or more processors in a multi-processing arrangement may also be employed to execute the sequences of instructions contained in main memory MM. In some embodiments, hard-wired circuitry may be used in place of or in combination with software instructions. Thus, the description herein is not limited to any specific combination of hardware circuitry and software.

[0071] The term “computer-readable medium” or “machine-readable medium” as used herein refers to any medium that participates in providing instructions to processor PRO for execution. Such a medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media include, for example, optical or magnetic disks, such as storage device SD. Volatile media include dynamic memory, such as main memory MM. Transmission media include coaxial cables, copper wire and fiber optics, including the wires that comprise bus BS. Transmission media can also take the form of acoustic or light waves, such as those generated during radio frequency (RF) and infrared (IR) data communications. Computer -readable media can be non-transitory, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, and EPROM, a FLASH-EPROM, any other memory chip or cartridge. Non-transitory computer readable media can have instructions recorded thereon. The instructions, when executed by a computer, can implement any of the operations described herein. Transitory computer-readable media can include a carrier wave or other propagating electromagnetic signal, for example.

[0072] Various forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to processor PRO for execution. For example, the instructions may initially be borne on a magnetic disk of a remote computer. The remote computer can load the instructions into its dynamic memory and send the instructions over a network. Computer system CS can receive the data and place the data on bus BS. Bus BS carries the data to main memory MM, from which processor PRO retrieves and executes the instructions. The instructions received by main memory MM may optionally be stored on storage device SD either before or after execution by processor PRO.

[0073] Computer system CS may also include a communication interface CI coupled to bus BS. Communication interface CI provides a two-way data communication coupling to a network link NDL that is connected to a local network LAN. For example, communication interface CI may be an integrated services digital network (ISDN) card or a modem to provide a data communication connection to a corresponding type of telephone line. As another example, communication interface CI may be a local area network (LAN) card to provide a data communication connection to a compatible LAN. Wireless links may also be implemented. In any such implementation, communication interface CI sends and receives electrical, electromagnetic, or optical signals that carry digital data streams representing various types of information.

[0074] Network link NDL typically provides data communication through one or more networks to other data devices. For example, network link NDL may provide a connection through local network LAN to a host computer HC. This can include data communication services provided through the worldwide packet data communication network, now commonly referred to as the “Internet” INT. Local network LAN (Internet) may use electrical, electromagnetic, or optical signals that carry digital data streams. The signals through the various networks and the signals on network data link NDL and through communication interface CI, which carry the digital data to and from computer system CS, are exemplary forms of carrier waves transporting the information.

[0075] Computer system CS can send messages and receive data, including program code, through the network(s), network data link NDL, and communication interface CI. In the Internet example, host computer HC might transmit a requested code for an application program through Internet INT, network data link NDL, local network LAN, and communication interface CI. One such downloaded application may provide all or part of a method described herein, for example. The received code may be executed by processor PRO as it is received, and/or stored in storage device SD, or other nonvolatile storage for later execution. In this manner, computer system CS may obtain application code in the form of a carrier wave. [0076] Various embodiments of the present systems and methods are disclosed in the subsequent list of numbered clauses. In the following, further features, characteristics, and exemplary technical solutions of the present disclosure will be described in terms of clauses that may be optionally claimed in any combination:

1. A semiconductor bonding system, comprising: a track comprising a path through a plurality of process stations; a plurality of substrate holders coupled to the track, each substrate holder configured to receive and hold a first substrate, and move the first substrate along the path through the plurality of process stations to enable the first substrate to be bonded to a second substrate; and a controller operatively coupled to the track and the plurality of substrate holders, the controller configured to control relative motion between the plurality of substrate holders to cause each substrate holder to move along the path through the plurality of process stations independently of other substrate holders, with ranges and speeds for each substrate holder that vary according to track position relative to the plurality of process stations.

2. The system of clause 1 , wherein each of the first substrates is a die and the second substrate comprises a semiconductor wafer.

3. The system of any of the previous clauses, wherein the process stations comprise a bonding station and at least one alignment station, a height and/or rotational adjustment station, a leveling station, and/or a placement station.

4. The system of any of the previous clauses, wherein the track comprises a horizontal and/or vertical axis for long stroke movement.

5. The system of any of the previous clauses, wherein the plurality of substrate holders are configured to move in a continuous closed loop movement, in a clockwise and/or anti-clockwise direction, along the path.

6. The system of any of the previous clauses, wherein the track comprises two or more parallel processing paths, a parallel processing path being separated from a main path, and associated with at least one of the bonding process stations.

7. The system of any of the previous clauses, wherein the track has an oval shape.

8. The system of any of the previous clauses, wherein the controller and the plurality of substrate holders are configured such that one or more operations at the plurality of process stations are performed while a given substrate holder is moving.

9. The system of any of the previous clauses, wherein the moving is controlled in concert with a timing of processing at a process station.

10. The system of any of the previous clauses, wherein the controller and the plurality of substrate holders are configured such that one or more operations at the plurality of process stations are performed while a given substrate holder is stopped, and others of the plurality of substrate holders are moving. 11. The system of any of the previous clauses, wherein a number of the plurality of substrate holders corresponds to a number of the process stations.

12. The system of any of the previous clauses, wherein a number of the plurality of substrate holders is equal to, more than, or less than a number of the process stations.

13. The system of any of the previous clauses, wherein the track and/or the plurality of substrate holders comprise one or more activation coils, one or more air bearings, a vacuum, a mechanical wheel, a magnetic bearing, a pressure vessel, a sliding bearing, a capacitor, and/or a spring.

14. The system of any of the previous clauses, wherein the track comprises one or more components configured to cause the plurality of substrate holders to move within a first actuation range, and the plurality of substrate holders comprise one or more components configured to cause the first substrate to move within a second actuation range, shorter than the first actuation range.

15. The system of any of the previous clauses, wherein each substrate holder is configured to move along the path, and in horizontal, vertical, and/or rotational directions relative to the track via a contactless actuator associated with each substrate holder.

16. The system of any of the previous clauses, wherein at a bonding station of the plurality of process stations, a given substrate holder is configured to be positioned by the controller with sufficient accuracy and force for bonding to the second substrate; or the given substrate holder is coarsely positioned relative to the second substrate, and the second substrate is moved relative to the given substrate holder with sufficient accuracy and force for bonding.

17. The system of any of the previous clauses, wherein at an alignment station of the plurality of process stations, a given substrate holder is configured to be positioned by the controller with sufficient accuracy for an alignment measurement by an alignment sensor; or the given substrate holder is coarsely positioned relative to the alignment sensor, and the alignment sensor is moved relative to the given substrate holder with sufficient accuracy for the alignment measurement.

18. The system of any of the previous clauses, wherein the semiconductor bonding system comprises multiple tracks.

19. The system of any of the previous clauses, wherein the plurality of substrate holders are configured to be moveable in different directions on the multiple tracks.

20. The system of any of the previous clauses, wherein the controller comprises one or more processors, one or more robots, one or more turrets, one or more conveyor belts, and/or one or more drums.

21. The system of any of the previous clauses, wherein the first substrates comprise donor dies, the donor dies held by carrier comprising a wafer foil frame, a reticle shaped carrier, a wafer shaped carrier, or individual trays with lids; and introduced to the semiconductor bonding system through a front opening universal pod (FOUP) of the system.

22. The system of any of the previous clauses, wherein the carrier is optically transparent and coated with a photosensitive material.

23. The system of any of the previous clauses, wherein each donor die is coupled to the carrier by something less than a full surface area of a donor die.

24. The system of any of the previous clauses, further comprising a gripper configured to remove the donor dies from the carrier and couple the donor dies with the plurality of substrate holders, one donor die per substrate holder.

25. The system of any of the previous clauses, wherein the gripper comprises an electrostatic gripper, a vacuum gripper, a gecko gripper, an air bearing gripper, or a mechanical gripper.

26. The system of any of the previous clauses, wherein the gripper is configured to grip a donor die based on a reference on the gripper, a location of the reference determined with a camera, interferometrically, via a grid plate, and/or capacitively.

27. The system of any of the previous clauses, wherein the gripper is configured to grip side surfaces and/or a back surface of a donor die.

28. The system of any of the previous clauses, wherein the gripper is configured to position a donor die on a mobile substrate holder that is configured to accept the donor die and be placed on the track for further processing.

29. The system of any of the previous clauses, wherein the plurality of process stations comprise a cleaning station configured to clean the first substrates before bonding.

30. The system of any of the previous clauses, wherein the plurality of process stations comprise an inspection station configured to detect topographic defects in the first substrates before bonding, the inspection station comprising a dark field imager, a level sensor, a Fourier imager, and/or a capacitive sensor.

31. The system of any of the previous clauses, wherein the plurality of process stations comprise a leveling station configured to level the first substrates relative to the second substrate before bonding.

32. The system of any of the previous clauses, wherein each of the plurality of substrate holders comprises a chuck configured to receive and hold a first substrate, and move the first substrate along the path through the plurality of process stations to enable the first substrate to be bonded to the second substrate.

33. The system of any of the previous clauses, wherein the track comprises a balance mass configured to counteract deformation and/or vibration in the semiconductor bonding system.

34. The system of any of the previous clauses, wherein each of the plurality of substrate holders, and/or each of the plurality of process stations comprise one or more isolators configured to isolate an environment of the track and the substrate holders from and environment of a process station.

35. The system of any of the previous clauses, wherein an isolator comprises a gasket, a plate, and/or a suction system.

36. A semiconductor bonding method, comprising: receiving and holding, with each of a plurality of substrate holders coupled to a track, a first substrate, and moving the first substrate along a path through a plurality of process stations to enable the first substrate to be bonded to a second substrate; and controlling, with a controller operatively coupled to the track and the plurality of substrate holders, relative motion between the plurality of substrate holders to cause each substrate holder to move along the path through the plurality of process stations independently of other substrate holders, with ranges and speeds for each substrate holder that vary according to track position relative to the plurality of process stations.

37. The method of clause 36, wherein each of the first substrates is a die and the second substrate comprises a semiconductor wafer.

38. The method of any of the previous clauses, wherein the process stations comprise a bonding station and at least one alignment station, a height and/or rotational adjustment station, a leveling station, and/or a placement station.

39. The method of any of the previous clauses, wherein the track comprises a horizontal and/or vertical axis for long stroke movement.

40. The method of any of the previous clauses, further comprising moving the plurality of substrate holders in a continuous closed loop movement, in a clockwise and/or anti-clockwise direction, along the path.

41. The method of any of the previous clauses, wherein the track comprises two or more parallel processing paths, a parallel processing path being separated from a main path, and associated with at least one of the bonding process stations.

42. The method of any of the previous clauses, wherein the track has an oval shape.

43. The method of any of the previous clauses, further comprising performing one or more operations at the plurality of process stations while a given substrate holder is moving.

44. The method of any of the previous clauses, further comprising controlling the moving in concert with a timing of processing at a process station.

45. The method of any of the previous clauses, further comprising performing one or more operations at the plurality of process stations while a given substrate holder is stopped, and others of the plurality of substrate holders are moving.

46. The method of any of the previous clauses, wherein a number of the plurality of substrate holders corresponds to a number of the process stations.

47. The method of any of the previous clauses, wherein a number of the plurality of substrate holders is equal to, more than, or less than a number of the process stations.

48. The method of any of the previous clauses, wherein the track and/or the plurality of substrate holders comprise one or more activation coils, one or more air bearings, a vacuum, a mechanical wheel, a magnetic bearing, a pressure vessel, a sliding bearing, a capacitor, and/or a spring.

49. The method of any of the previous clauses, further comprising moving, with one or more components of the track, the plurality of substrate holders within a first actuation range, and moving, with one or more components of the plurality of substrate holders the first substrate within a second actuation range, shorter than the first actuation range.

50. The method of any of the previous clauses, wherein each substrate holder is configured to move along the path, and in horizontal, vertical, and/or rotational directions relative to the track via a contactless actuator associated with each substrate holder.

51. The method of any of the previous clauses, further comprising, at a bonding station of the plurality of process stations, positioning a given substrate holder with the controller with sufficient accuracy and force for bonding to the second substrate; or coarsely positioning the given substrate holder relative to the second substrate, and moving the second substrate relative to the given substrate holder with sufficient accuracy and force for bonding.

52. The method of any of the previous clauses, further comprising, at an alignment station of the plurality of process stations, positioning a given substrate holder with the controller with sufficient accuracy for an alignment measurement by an alignment sensor; or coarsely positioning the given substrate holder relative to the alignment sensor, and moving the alignment sensor relative to the given substrate holder with sufficient accuracy for the alignment measurement.

53. The method of any of the previous clauses, wherein the track comprises multiple tracks.

54. The method of any of the previous clauses, wherein the plurality of substrate holders are configured to be moveable in different directions on the multiple tracks.

55. The method of any of the previous clauses, wherein the controller comprises one or more processors, one or more robots, one or more turrets, one or more conveyor belts, and/or one or more drums.

56. The method of any of the previous clauses, wherein the first substrates comprise donor dies, the donor dies held by carrier comprising a wafer foil frame, a reticle shaped carrier, a wafer shaped carrier, or individual trays with lids; and are introduced through a front opening universal pod (FOUP).

57. The method of any of the previous clauses, wherein the carrier is optically transparent and coated with a photosensitive material.

58. The method of any of the previous clauses, wherein each donor die is coupled to the carrier by something less than a full surface area of a donor die.

59. The method of any of the previous clauses, further comprising removing, with a gripper, the donor dies from the carrier and coupling the donor dies with the plurality of substrate holders, one donor die per substrate holder.

60. The method of any of the previous clauses, wherein the gripper comprises an electrostatic gripper, a vacuum gripper, a gecko gripper, an air bearing gripper, or a mechanical gripper.

61. The method of any of the previous clauses, wherein the gripper is configured to grip a donor die based on a reference on the gripper, a location of the reference determined with a camera, interferometrically, via a grid plate, and/or capacitively.

62. The method of any of the previous clauses, wherein the gripper is configured to grip side surfaces and/or a back surface of a donor die.

63. The method of any of the previous clauses, wherein the gripper is configured to position a donor die on a mobile substrate holder that is configured to accept the donor die and be placed on the track for further processing.

64. The method of any of the previous clauses, further comprising cleaning the first substrates before bonding at a cleaning station the plurality of process stations.

65. The method of any of the previous clauses, further comprising detecting topographic defects in the first substrates before bonding at an inspection station of the plurality of process stations, the inspection station comprising a dark field imager, a level sensor, a Fourier imager, and/or a capacitive sensor.

66. The method of any of the previous clauses, further comprising leveling the first substrates before bonding at a leveling station of the plurality of process stations.

67. The method of any of the previous clauses, wherein each of the plurality of substrate holders comprises a chuck configured to receive and hold a first substrate, and move the first substrate along the path through the plurality of process stations to enable the first substrate to be bonded to the second substrate.

68. The method of any of the previous clauses, further comprising counteracting deformation and/or vibration with a balance mass of the track.

69. The method of any of the previous clauses, further comprising isolating an environment of the track and the substrate holders from and environment of a process station with one or more isolators of each of the plurality of substrate holders, and/or each of the plurality of process stations.

70. The method of any of the previous clauses, wherein an isolator comprises a gasket, a plate, and/or a suction system.

[0077] The descriptions above are intended to be illustrative, not limiting. Thus, it will be apparent to one skilled in the art that modifications may be made as described without departing from the scope of the claims set out below.

Claims

2. The system of claim 1 , wherein each of the first substrates is a die and the second substrate comprises a semiconductor wafer.

3. The system of claim 1, wherein the process stations comprise a bonding station and at least one alignment station, a height and/or rotational adjustment station, a leveling station, and/or a placement station.

4. The system of claim 1 , wherein the track comprises a horizontal and/or vertical axis for long stroke movement.

5. The system of claim 1, wherein the controller and the plurality of substrate holders are configured such that one or more operations at the plurality of process stations are performed while a given substrate holder is moving.

6. The system of claim 5, wherein the moving is controlled in concert with a timing of processing at a process station.

7. The system of claim 1, wherein the controller and the plurality of substrate holders are configured such that one or more operations at the plurality of process stations are performed while a given substrate holder is stopped, and others of the plurality of substrate holders are moving.

8. The system of claim 1, wherein the track comprises one or more components configured to cause the plurality of substrate holders to move within a first actuation range, and the plurality of substrate holders comprise one or more components configured to cause the first substrate to move within a second actuation range, shorter than the first actuation range.

9. The system of claim 1, wherein each substrate holder is configured to move along the path, and in horizontal, vertical, and/or rotational directions relative to the track via a contactless actuator associated with each substrate holder.

10. The system of claim 1, wherein at a bonding station of the plurality of process stations, a given substrate holder is configured to be positioned by the controller with sufficient accuracy and force for bonding to the second substrate; or the given substrate holder is coarsely positioned relative to the second substrate, and the second substrate is moved relative to the given substrate holder with sufficient accuracy and force for bonding.

11. The system of claim 1, wherein at an alignment station of the plurality of process stations, a given substrate holder is configured to be positioned by the controller with sufficient accuracy for an alignment measurement by an alignment sensor; or the given substrate holder is coarsely positioned relative to the alignment sensor, and the alignment sensor is moved relative to the given substrate holder with sufficient accuracy for the alignment measurement.

12. The system of claim 1, wherein the track comprises a balance mass configured to counteract deformation and/or vibration in the semiconductor bonding system.

13. The system of claim 1, wherein each of the plurality of substrate holders, and/or each of the plurality of process stations comprise one or more isolators configured to isolate an environment of the track and the substrate holders from and environment of a process station.

14. A semiconductor bonding method, comprising: receiving and holding, with each of a plurality of substrate holders coupled to a track, a first substrate, and moving the first substrate along a path through a plurality of process stations to enable the first substrate to be bonded to a second substrate; and controlling, with a controller operatively coupled to the track and the plurality of substrate holders, relative motion between the plurality of substrate holders to cause each substrate holder to move along the path through the plurality of process stations independently of other substrate holders, with ranges and speeds for each substrate holder that vary according to track position relative to the plurality of process stations.

15. The method of claim 14, further comprising performing one or more operations at the plurality of process stations while a given substrate holder is stopped, and others of the plurality of substrate holders are moving.