Method to populate a cartridge substrate with microdevices

Abstract

The present disclosure relates to various methods of building multi-cartridges. The present disclosure relates to populating microdevices on a substrate. In particular microdevices are filled via fluid solution process.

Description

METHOD TO POPULATE A CARTRIDGE SUBSTRATE WITH MICRODEVICESCLAIM OF PRIORITY

[0001] This application claims priority to U.S. Provisional Application No. 63 / 566,851 filed March 18, 2024, titled “Cartridge Formation,” which is incorporated by reference in its entirety.BACKGROUND

[0002] Methods to transfer microdevices with an optical structure are useful for semiconductor device fabrication.SUMMARY

[0003] The present disclosure relates to a method to populate a cartridge substrate, where the cartridge substrate includes cartridges for microdevices. The microdevices may be mixed in a solution and dispersed over a surface of the cartridge substrate. The cartridges can attract and accept the microdevices.BRIEF DESCRIPTION OF THE DRAWINGS

[0004] Material described herein is illustrated by way of example and not by way of limitation in accompanying figures. For simplicity and clarity of illustration, elements illustrated in figures are not necessarily drawn to scale. For example, dimensions of some elements may be exaggerated relative to other elements for clarity. Also, various physical features may be represented in their simplified “ideal” forms and geometries for clarity of discussion, but it is nevertheless to be understood that practical implementations may approximate illustrated ideals. For example, smooth surfaces and square intersections may be drawn in disregard of finite roughness, cornerrounding, and imperfect angular intersections characteristic of structures formed by nanofabrication techniques. Further, where considered appropriate, reference labels have been repeated among figures to indicate corresponding or analogous elements.

[0005] The foregoing and other advantages of the disclosure will become apparent upon reading the following detailed description and upon reference to the drawings.

[0006] Figure 1A is a flow diagram for a method to insert microdevices within cartridges and transferring microdevices from the cartridges.

[0007] Figure IB is a flow diagram for a method to populate a cartridge substrate, in at least one example.

[0008] Figure 2A illustrates a plan view of a cartridge substrate including cartridges for inserting microdevices, in at least one example.

[0009] Figure 2B illustrates a structure of Figure 1A following a process to insert microdevices within the cartridges, in at least one example.

[0010] Figure 3A illustrates an enhanced plan view of a portion of a cartridge within a cartridge substrate, in at least one example.

[0011] Figure 3B illustrates a cross-sectional view of the cartridge in Figure 3A, through a line A- A’, in at least one example.

[0012] Figure 3C illustrates a cross-sectional view of features in Figure 3A, through a line B- B’, in at least one example.

[0013] Figure 3D is an isometric illustration of cartridge illustrated in structure Figure 3A, in at least one example.

[0014] Figure 4A illustrates an experimental set up including the cartridge substrate illustrated in Figure 1A, within an apparatus implemented to insert microdevices.

[0015] Figure 4B illustrates an experimental set up of Figure 4A following a process to flow fluid comprising microdevices, over a surface of cartridge substrate, in at least one example.

[0016] Figure 4C illustrates a plan view of the structure in Figure 4B, in at least one example.

[0017] Figure 4D is an enhanced plan view illustration of a microdevice captured in a cartridge, in at least one example.

[0018] Figure 4E illustrates a cross section of structure in Figure 4D, through a line A-A’, in at least one example.

[0019] Figure 4F illustrates a cross section of a setup utilizing cartridge substrate illustrated in Figure 1A, in at least one example.

[0020] Figure 5A illustrates a cross-sectional view of an electrode structure designed to create a magnetic field, in at least one example.

[0021] Figure 5B illustrates a plan view of the electrode structure in Figure 5A, in at least one example.

[0022] Figure 5C illustrates a plan view of the electrode in Figure 5A, in at least one example.

[0023] Figure 5D illustrates a cross-sectional view of an electrode structure designed to influence magnetic field, in at least one example.

[0024] Figure 6A is an isometric illustration of an enhanced portion of a cartridge overlapped with an electrode structure, in at least one example.

[0025] Figure 6B illustrates a cross-section through a line A- A’ of the structure in Figure 6A, in at least one example.

[0026] Figure 6C illustrates a schematic of a direction of current through electrode, a direction of magnetic field within microdevice and direction of resultant force, in at least one example.

[0027] Figure 7A illustrates an apparatus including electrode structure in Figure 5A designed to attract suspended microdevices through a magnetic force in a fluid, in at least one example.

[0028] Figure 7B illustrates apparatus in Figure 7A following a process to flow a solution comprising suspended microdevices over energized electrode structures, in at least one example.

[0029] Figure 8 illustrates a setup including an electrode structure in Figure 5D designed to attract suspended microdevices through a magnetic force in a fluid, in at least one example.

[0030] While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments or implementations have been shown by way of example in the drawings and will be described in detail herein. It should be understood, however, that the disclosure is not intended to be limited to the particular forms disclosed. Rather, the disclosure is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of a disclosure as defined by the appended claims.DETAILED DESCRIPTION

[0031] At least one example describes a cartridge substrate comprising cartridges designed to house microdevices suspended in a fluid above the cartridge substrate. While at least one example is described with reference to microdevices suspended in a fluid, the process methodology can be utilized in any application where placement of a suspended object within a cartridge is useful. In at least one example, microdevices placed within cartridges can be micro light emitting diodes (microLEDs) of varying colors. Here, numerous specific details are set forth, such as structural schemes and detailed fabrication methods to provide a thorough understanding of examples of present disclosure. It will be apparent to one skilled in the art that examples of present disclosure may be practiced without these specific details. In otherinstances, well-known features, such as process equipment and device operations, are described in lesser detail to not unnecessarily obscure examples of present disclosure. Furthermore, it is to be understood that examples shown in Figures are illustrative representations and are not necessarily drawn to scale.

[0032] A microdevice on a donor cartridge substrate has a top face away from the cartridge substrate and a bottom face towards the cartridge substrate. At least part of the top or bottom face of the microdevice is covered by an optical layer (e.g. color conversion material, or lens, etc.). In at least one example, a layer may be utilized to fix a bottom surface of the microdevice to the donor cartridge substrate. The layer can be adhesive or have anchors. In at least one example, a release layer between the layer and the cartridge substrate can be implemented. The cartridge substrate can further include light coupling or an encapsulation layer between the microdevice and the optical layer. In at least one example, a protection layer can cover at least a surface of microdevices that is not covered by the optical layer. The protection layer can be extended on an edge of the surface covered by the optical layer to house at least part of the optical layer. The protection layer can be reflective to direct the light toward the optical layer. In a related example, the devices in the donor cartridge substrate can have more than one type of optical layer. In at least one example, the different devices can have different optical layers. For instance, one device can have green color conversion layer and the other one red color conversion layer. The devices are transferred into a receiver substrate to form an array of microdevices. The optical layer can create different functionality in the devices such as color or directing the input or output light to a specific direction or modifying light profiles. The microdevices can have pads on either top, bottom, or sides that are not top or bottom sides. The pads provide electrical connections to the device. In at least one example, the cartridge substrate is coupled to the devices through the pads. The microdevices may have several layers such as p- layer, n-layer, blocking layers, buffer layers, ohmic layers, and active layers. In at least one example, active layers can be multi quantum well (MQW). The microdevices may comprise microLEDs, where microLEDs may have dimensions in a nanometer scale.

[0033] Transferring microdevices or micro-optoelectronic devices into a system substrate can enable several new applications. In at least one example, there are at least two main challenges associated with transferring microdevices. Matching a pitch between microdevice pitch within a donor cartridge substrate and a system substrate pitch can limit the use of the same microdevicefor different applications, and uniformity of microdevices can be mismatched where the microdevices can have variations in size, have defects that can change their sizes etc., that can potentially impact placement in the cartridge substrate.

[0034] One method is to mix the microdevices into a fluid to form a solution and spread the solution over the surface of the system substrate to transfer the devices. Here solution does not imply that microdevices are soluble in the fluid and is used to describe microdevices within a fluid. This makes the device and the system substrate complex processes and limits the type of microdevices that can be transferred. In at least one example, microdevices can have differing characteristics, where they may be manipulated by selectively modifying one or more parameters such as the density of the fluid, rate of flow of the fluid, using electrostatic properties, physical characteristics, etc., to modify the behaviors of different microdevices. For example, a first microdevice may be less dense than a second microdevice, and increasing the flow rate of the solution may allow the second microdevice which is denser to settle out onto a cartridge substrate while the less dense microdevice may be maintained in solution. In at least one example, a first microdevice may have a stronger positive charge than a second microdevice, therefore when a negative charge is given to the cartridge substrate, the first microdevice may settle out at a lower negative charge than would be required to settle out the second microdevice.

[0035] In at least one example, microdevices can be integrated into a cartridge that is designed to attract microdevices suspended in a flowing solution. For example, the cartridge may comprise a keyed interface such that only microdevices having a particular shape can be inserted into the cartridge. In at least one example, a first microdevice which is denser than a second microdevice, may be allowed to settle onto the donor cartridge substrate and registered into the cartridges using a control method such as modifying the flow rate or direction of the fluid, or by using properties such as a chemical affinity or electrostatic charges to attract, align, and hold the microdevices in place. In at least one example, the chemical affinity or electrostatic charges may be manipulated by adjusting the pressure or temperature of the donor cartridge substrate, fluid, or both the donor cartridge substrate and the fluid. In at least one example, manufacturing of microLED displays needs efficient transfer of microLEDs from their growth substrate to a display backplane. Traditional methods like pick-and-place and laser-based transfer of microLEDs faces challenges in terms of speed, accuracy, and yield. Innovative approaches, such as cartridge-based systems, have been developed to address these issues. In at least one example,a cartridge-based system is known as MicroSolid Printing™. This method utilizes micro-scale cartridges to hold and transfer microLEDs onto the display substrate with high precision and efficiency. Each cartridge can carry thousands of microLEDs, enabling rapid and accurate placement. This technology offers several advantages such as high throughput. The system supports the simultaneous use of over 100 cartridges, significantly increasing the speed of microLED transfer compared to traditional methods. Another advantage is enhanced yield. Integrated inspection mechanisms within the cartridges allow for real-time defect detection and correction, reducing repair costs and improving overall yield. Another advantage is versatility. The process to suspend microdevices in a fluid and transfer to cartridges is compatible with different microLED types, including lateral, vertical, and flip-chip configurations, and can handle microLEDs that are smaller than five microns. Once microdevices are integrated into a donor cartridge substrate, the donor cartridge substrate can be aligned with a system substrate, where the microdevices can be transferred by applying pressure or temperature.

[0036] Figure 1A is a flow diagram for a method 100 to insert microdevices in cartridge within a cartridge substrate and transferring microdevices from the cartridge substrate, in at least one example. In at least one example, method 100 begins at operation 110 with a filling stage. During the filling operation some cartridges within cartridge substrate may be filled with microdevices suspended in a solution. In at least one example, the filling operation is complete when the difference between the initial density of microdevices in solution and the final density of microdevices in solution is within a set range such that the density change indicates that the cartridges have been filled. Method 100 continues at operation 120, where cartridge substrate may undergo a process to remove any oddly positioned microdevices during a trimming stage. Trimming may comprise the adjustment of one or more process parameters, such as the rate or direction of fluid flow, the temperature, pressure, electrostatic properties, etc., so as to allow oddly positioned microdevices to be displaced. In at least one example, method 100 may continue to transition between the filling and trimming stages or operation 110 and operation 120, respectively, as indicated by arrow 125. In at least one such example, cartridge substrate undergoes a filling operation and a successive trimming operation. In at least one such example, a sub-inspection operation can be part of the iteration process.

[0037] The trimming and filling operations can be the same or different physical stages. For example, the filling operation may comprise iterative trimming operations to remove or orientmicrodevices which are improperly arranged within the cartridges. This may comprise adjusting the flow rate of the fluid solution or altering a property of the solution such as the temperature, pressure, or the electrostatic properties of the cartridges to selectively attract or release microdevices such that the microdevices which are improperly arranged may be adjusted or displaced. In at least one example, these operations and the parameters utilized during each operation may be controlled using an artificial intelligence or machine learning model which optimizes the parameters for each operation, which may be informed via sensor data, such as temperature, pressure, flow rate, density, or imaging data which may be acquired via an optical camera sensor, or other imaging technologies, such as electron microscopy. Method 100 continues at operation 130 with an inspection operation. In at least one example, the inspection operation may be a final inspection operation implemented to find any residual defects (such as microdevices or any other contaminants from the fluid) remaining on cartridge substrate. The inspection operation may utilize at least one artificial intelligence or machine learning model to perform methods such as image recognition to identify residual defects, or to alternatively confirm that each cartridge is populated with a desired microdevice. Method 100 continues at operation 140 with a repair operation. In at least one example, operation 140 may be performed to manage defects in cartridge substrate. Repair operations may comprise a trimming operation to remove excess or misplaced microdevices. Alternatively, repair operations may comprise further filling operations to fill vacant cartridges. Additional processes not described may provide functions such as removing contaminants, or utilization of traditional methods, such as pick and place, to correct defects in the cartridge substrate. Method ends at operation 150 where microdevices within cartridges are transferred from the cartridge substrate into a system cartridge substrate, when defects are below a set limit. In at least one example, the defect limit may be dynamically determined based on the types and locations of the defects. In such embodiments, the defect limit may be determined using an artificial intelligence or machine learning model to determine whether the identified defects will impact the end use application or design specification requirements. An artificial intelligence or machine learning model may further determine whether repair operations may be more costly than producing additional microdevice laden cartridge substrates.

[0038] Figure 1A also illustrates the process steps (or stages) for forming random cartridges and moving microdevices into a system substrate. The process of filling the cartridge substrate withmicrodevices may include several iterations. During the filling stage at operation 110, the predefined location of the cartridge substrate is filled with microdevices using the first solution. After this stage, the cartridge substrate may undergo a process to remove the oddly positioned microdevices during a trimming stage at operation 120. To remove the oddly positioned microdevices, a force that is less than the force holding the properly positioned devices in place but larger than the force holding the oddly positioned devices can be used. The force can be caused by agitation of a solution or spraying liquid or gas. The gas can be dry, clean air, nitrogen, or other gasses. In at least one example, liquid can be DI water, alcohol, or other liquids. After this stage, the cartridge could go to the filling station. In at least one example, , the same solution as the first solution can be used, or a separate solution can be used. In at least one example, transition between the filling and trimming stage can continue until the cartridge has a predefined percentage of the spots filled with microdevice.

[0039] After locations in the cartridge substrate are filled with microdevices, the process stops, and the cartridge is removed (or the solution is removed). The cartridge is inspected at operation 130 to ensure all the positions are filled with microdevices and no tilted or oddly oriented devices. In at least one example, repair may be done to fill the empty spots, fix the orientation, or replace the defective devices in repair stage at operation 140. In at least one example, cartridges are aligned with the system substrate, and the devices on the cartridge are transferred into the system substrate.

[0040] In at least one example, repetition of the above process can be limited to a set number. In at least one example, the trimming and filling stages can be the same or different physical stages. In at least one example, there can be multiple filling or trimming stages. In at least one example, after this cycle, the cartridges go to inspection stage at operation 130 to find any defects. The inspection stage can be part of the trimming stage. In at least one example, the cartridge can go to repair stage at operation 140, where the defects in the cartridge are managed. In at least one example, after this stage, the cartridge is ready for transfer stage at operation 150, where the microdevices are transferred from the cartridge into the system substrate.

[0041] In at least one example, filling the microdevice may include low agitation of solutions to move the microdevices around and using an attractive force in the cartridge to attract the device to the intended locations. In at least one example, the attraction force can be suction,electromagnetic or electrostatic. In at least one example, the cartridge can have more than one device per pixel area and may be used to populate more than once.

[0042] Figure IB is a flow diagram for a method 160 to populate a cartridge substrate, in at least one example. Method begins at operation 162 by providing a cartridge substrate comprising locations, in at least one example. In at least one example, the cartridge substrate includes locations spaced throughout the cartridge substrate. In at least one example, locations may be trenches formed within the cartridge substrate. In alternate embodiments, locations may comprise a keyed interface, such as depressions or indentations of a shape matching one or more microdevices. Method continues at operation 164 by providing a fluid comprising microdevices. In at least one example, the fluid may include a set number density of microdevices that are suspended within the fluid. Method continues at operation 166 by flowing fluid comprising the microdevices over the cartridge substrate. Method ends at operation 168 by collecting micro devices within cartridges by enabling cartridges to accept microdevices.

[0043] Figure 2A illustrates a plan view of a structure 200A. In at least one example, structure 200A includes cartridge substrate 202 with locations 204. In at least one example, locations 204 are designed for housing or inserting microdevices, using one or more methods described below. In at least one example, locations 204 comprise trenches, where trenches can be rectangular, circular, or any arbitrary shape. In at least one example, locations 204 comprise a shape that match shape of microdevices to be inserted. In at least one example, locations 204 can be uniformly distributed across within cartridge substrate 202. In at least one example, adjacent locations 204 can be spaced apart by a distance X along an X-axis direction and a distance Y along a Y-axis direction, as shown in the figure. In at least one example, distances X and Y are greater than the size of the locations 204 or microdevices for practical considerations. In at least one example, distances X and Y can 1.5 to 3 times greater than corresponding dimensions along X-axis and Y-axis of microdevices (see below). In at least one example, the cartridges may be arranged in a grid, equidistant in the X-axis and the Y-axis. In other embodiments, the cartridges may be arranged in non-grid layouts, such as offsetting alternating rows, or arranging in a radial pattern. In at least one example, the cartridges may be arranged in a random pattern or to form predetermined shapes, such as segments of an 8-segment display. In at least one example, cartridge substrate 202 can comprise an insulator or semiconductor material comprising one or more layers, as will be discussed further below. In at least one example, cartridge substrate 202includes silicon, or insulators like saphire, glass, polymers, polyimides or other material compatible with process operations discussed herein. In at least one example, thickness and structure of cartridge substrate 202 can depend on applications and requirements such as the number of conductive and non- conductive layers, masks, insulation, etc.

[0044] Figure 2B illustrates a structure 200B. In at least one example, structure 200B is an illustration of structure 200A in Figure 2A with microdevices 206 inserted within locations 204. Different process methodologies and apparatus may be implemented to insert microdevices 206 into locations 204, as will be discussed below. In at least one example, all locations 204 are filled with microdevices 206 as shown in the illustration. In at least one example, locations 204 have at least a same dimension as a dimension of a microdevice 206. For practical considerations, locations 204 have a dimension that is larger than the dimensions of a microdevice 206. Here, the term “dimensions” refers to at least two or more sides where, for example, location 204 has at least three or more sides. In the illustrative example, locations 204 have dimensions that are larger than dimensions of a microdevice 206 and are placed within a boundary of each cartridge. In at least one example, a cartridge and microdevice may be any shape, such as square or rectangular, with indents or extensions, and may be curved subject to VLSI (very large scale integration) imaging and masking techniques. Dimensions may comprise additional parameters such as orientation or depth. In at least one example, at least one side of a microdevice 206 may be in contact with a sidewall of location 204.

[0045] Figure 3 A illustrates an enhanced plan view of a structure 300A. In at least one example, structure 300A illustrates a plan view of location 204 within cartridge substrate 202. In at least one example, location 204 can have an arbitrary shape and can be designed to accommodate a shape of a microdevice 206 (not shown) to be captured or housed. In at least one example, shapes of locations 204 may be a rectangle, circle, ellipse, or etc. In at least one example, shape of location 204 may be a trapezoid, as illustrated. In at least one example, the direction of taper in the trapezoid may be designed to favor capture of microdevices. In at least one example, location 204 includes a via 302. In at least one example, via 302 is designed to provide a pathway for a suction force during operation, where via 302 extends through cartridge substrate 202.

[0046] In at least one example, cartridge substrate 202 includes a through via 308 for suction force in places where microdevices 206 are designed to land. In at least one example, locations204 where a microdevice 206 lands can be a trench. In at least one example, the trench may be larger than the microdevice dimensions.

[0047] In another example, location 204 may comprise a conductor capable of generating an electrostatic or electromagnetic force on a microdevice 206. In at least one example, a location 204 may comprise a chemical which may function as an adhesive. Adhesive properties may be modified by manipulating the temperature of the location 204. In at least one example, the location 204 may contain solder, which may be melted and solidified by manipulating the temperature of the location 204.

[0048] In at least one example, cartridge substrate 202 can include features 304 in a vicinity of location 204. Features 304 are designed to have a shape that can enable movement of microdevices in the vicinity of location 204, without trapping them. In at least one example, features 304 can be trench lines formed within cartridge substrate 202. In at least one example, trench lines can also promote flow of fluid. In at least one example, at least one dimension of feature 304 is less than the smallest dimension of the microdevice to avoid trapping microdevices. In at least one example, the smallest dimension can be along the Y-axis direction in the figure. In at least one example, feature 304 can be elongated and comprises a length that is at least twice that of the longest dimension of location 204. In at least one example, surface area of feature 304 is smaller than a plan view surface area of microdevices.

[0049] In at least one example, cartridge substrate 202 may have trenches or features 304 around location 204. In at least one example, features 304 are 3D structures or 3D trenches. In at least one example, features 304 around location 204 are smaller than the size of microdevices. In at least one example, features 304 facilitate movement of microdevices outside locations 204.

[0050] In at least one example, when solution with microdevices (to be discussed below) is agitated, microdevices move around on the surface of cartridge substrate 202. In at least one example, cartridge substrate 202 has a bottom surface that is open for solutions to pass through via 302. In at least one example, can assist in moving microdevices toward locations 204 and hold the microdevices in the trenches. In at least one example, a suction force can be added to the bottom surface to facilitate transfer. In at least one example, the suction force can be modulated as more devices are trapped in locations 204.

[0051] Figure 3B illustrates a cross-sectional view of structure 300B. In at least one example, structure 300B illustrates location 204 in Figure 3A, through a line A-A’, in at least oneexample. As shown location 204 has a depth DT and a length LT. In at least one example, depth DT can range between 0.1 microns and 200 microns, and a length LT can range between 0.1 microns and 200 microns. In at least one example, via 302 has a width Wv, between 0.1 microns and 200 microns. In at least one example, when via 302 is circular, width Wv may be a diameter. In at least one example, width Wv may be determined by a suction force to be implemented to pull a microdevice on surface 204A of location 204. In at least one example, width Wv is designed to provide a sufficient suction force.

[0052] As shown via 302, extends through cartridge substrate 202. In at least one example, via 302 has a depth Dv, where depth Dv is a balance of thickness of cartridge substrate 202 remaining after formation of location 204.

[0053] Figure 3C illustrates a cross-sectional view of structure 300C. Structure 300C illustrates cross-sectional profiles of features 304 in Figure 3A, through a line B-B’, in at least one example. In at least one example, when features 304 are trenches, depth DF and width WF of features 304 may be customized to direct fluid flow. In at least one example, depth DF and width WF may be substantially uniform within each feature 304 as shown. In other examples, depth DF and width WF may be different within different features 304. In other examples, depth DF and width WF may be uniform within features 304 in a first region but different from features 304 in an adjacent second region. In at least one such example, variations in depth DF and width WF from one region to another may be implemented to direct fluid flow. In at least one example, trenches have vertical or substantially vertical sidewalls, as shown. In at least one example, trenches can have tapered sidewalls.

[0054] Figure 3D is an isometric illustration of location 204 illustrated in structure 300A (Figure 3A). In at least one example, sidewalls of location 204 are vertical or substantially vertical. In at least one example, sidewalls of cartridges may be tapered to match a profile of micro devices to be inserted.

[0055] Figure 4A illustrates a cross section of an apparatus 400, in at least one example. In at least one example, apparatus 400 includes a stage 402 to support cartridge substrate 202, a reservoir 404 under stage 402, and a suction device 406 coupled with reservoir 404. In at least one example, suction device 406 can be a pump. In at least one example, apparatus 400 further includes a housing 408 that is implemented to support fluid containment and flow. In at least one example, housing 408 includes an inlet 410 and an outlet 412. In at least one example, inlet410 and outlet 412 are examples of a solution inlet and a solution outlet, respectively. In at least one example, housing 408 further includes one or more agitators such as agitator 414A and agitator 414B that are implemented to stir fluid. In at least one example, an external agitator may be implemented to shake apparatus 400. In at least one example, agitator 414A and agitator 414B may comprise a pump, paddle, source of pressurized gas, source of a second fluid, ultrasonics etc. In at least one example, stage 402 may act as an agitator by moving cartridge substrate 202 through the fluid. In at least one example, stage 402 may further vibrate, oscillate, or etc., to aid microdevices 206 to settle into the locations 204. In at least one example, an agitator may introduce an electrical current which may induce ionization which may result in movement of solution (discussed below).

[0056] In at least one example, cartridge substrate 202 rests on stage 402. In at least one example, stage 402 may be a support structure at a periphery of housing 408. In at least one example, inlet 410 may be at a level above cartridge substrate 202 to provide fluid into housing 408. In at least one example, outlet 412 may be at a level of or below a level of cartridge substrate 202 to enable fluid to flow out of housing 408. In at least one example, inlet 410 and outlet 412 may be large (tall and wide) to enable microdevices to flow through. In at least one example, there can be more than one inlet such as inlet 410 along Y-axis direction. In at least one example, there can be more than one outlet such as outlet 412 along Y-axis direction. In at least one example, fluid flow may be controlled such that the fluid flows over a fractional part of the cartridge substrate 202. In at least one example, fluid may be moved across the cartridge substrate 202 as necessary to achieve the population of locations 204 with microdevices 206.

[0057] Figure 4B illustrates a cross section of apparatus 400 in Figure 4A following a process to flow solution 416 comprising microdevices 206, within housing 408, in at least one example. In at least one example, solution 416 is introduced into housing 408 through inlet 410. In at least one example, microdevices 206 can be dispersed in solution 416 by different means, such as sonication or via dispersion agents. The number density of microdevices 206 per unit volume of fluid can be adjusted to control fluid flow and control density of microdevices 206 within housing 408 at any given time.

[0058] In at least one example, solution 416 can be introduced from openings at a top surface of housing 408. In at least one example, the openings at the top surface of housing 408 may have a same or substantially the same dimensions as dimensions of inlet 410. In at least one example,upon being introduced in housing 408, solution 416 is directed towards outlet 412. In at least one example, solution 416 is also directed towards via 302, within each location 204, by a pull force as illustrated by arrows 417. In at least one example, the pull force is generated by suction device 406. In at least one example, as solution 416 is pulled towards each via 302, microdevices 206 are also influenced into moving towards locations 204. In at least one example, constant flow of solution 416 between inlet and outlet and within vias 302 facilitates movement of microdevice on surface of cartridge substrate 202. Locations 204 are enabled to accept microdevices 206. In at least one such example, some microdevices such as microdevice 206A can move along cartridge substrate 202 and be captured within locations 204, as shown. In at least one example, as solution 416 flows within housing 408, agitator 414A and agitator 414B can be utilized to stir solution 416, to move microdevices 206. In at least one such example, microdevices 206 move around on the surface 202A of cartridge substrate 202. In at least one example, agitator 414A and agitator 414B can be utilized to stir solution 416, to move microdevices 206 which may include slowing or stopping the flow of solution 416 into the housing 408. In at least one such example, housing 408 is filled with solution 416 and both inlet 410 and outlet 412 can be closed. In at least one example, portions of solution 416 exiting through via 302 form droplets 418 that accumulate into a fluid component 420 within reservoir 404. In at least one example, reservoir 404 does not contain any microdevices 206. In at least one example, the solution 416 collected in reservoir 404 may be reintroduced into the housing 408 to agitate the solution within the housing 408. In at least one example, the flow of the solution introduced into and within the housing 408 may be controlled via an artificial intelligence or machine learning model to optimize the flow of the solution over the cartridge substrate 202 such that the microdevices 206 settle into the locations 204.

[0059] Figure 4C is a plan view illustration of apparatus 400 in Figure 4B, in at least one example. In at least one example, inlet 410 and outlet 412 span a substantial portion of a width of housing 408. In at least one example, as solution 416 flows between inlet 410 and outlet 412, microdevices 206 flow in random directions, but have a general trajectory that propels them in a positive X-axis direction in the figure. In at least one example, some microdevices 206A are captured within locations 204, as shown. An enhanced plan view illustration of a microdevice 206A captured in location 204 is illustrated in Figure 4D. In at least one example, shape of microdevice 206 may match shape of location 204. In at least one example, shape andorientation of location 204 and shape of microdevice 206 can be designed to orient microdevice 206 with a specific orientation when captured. In at least one example, microdevice 206 can rotate in the fluid and orient within location 204, as shown. In at least one example, the microdevices 206 and locations 204 may be shaped such that they will mate in a single desired orientation. In at least one example, 206A is captured in a manner that leaves a space between sidewalls of microdevices and sidewalls of location 204. in at least one example, microdevices 206 may be allowed space to move and be oriented within the locations 204. In at least one example, fluid may be flowed across the cartridge substrate 202 in a manner where a shape of microdevices 206 and orientation of cartridge can aid with movement of microdevices 206 to position them in an orientation that is conducive for capture. In at least one such example, capture of microdevices 206 may be aided by aligning direction of fluid flow with a fin-like structure of microdevices 206 and location 204. In other examples, a front portion of microdevice 206A may be in contact with a sidewall of location 204 as illustrated in Figure 4C after capture.

[0060] Figure 4E illustrates a cross section of structure in Figure 4D, through a line A-A’, in at least one example. In examples, depth DT of location 204 can be same as, greater than, or less than thickness TM of microdevice 206. In the illustrative example, thickness TM of microdevice 206 is greater than depth DT of location 204. In at least one example, a depth DT that is greater than thickness TM, can be useful to prevent more than one microdevice 206 to be accidentally confined within a location 204. In at least one example, the suction force through via 302 can be sufficiently strong to capture microdevice 206 within location 204, as shown. In at least one example, once captured microdevice 206 is held within location 204 with a holding force strong enough to prevent dislodging. The force may be exerted by creating a pressure differential between an upper surface and a lower surface of cartridge substrate 202. In at least one example, a region of lower pressure can form beneath the cartridge substrate 202 and can pull the microdevices into locations 204. In at least one example, the force may be generated via electromagnetic or electrostatic means induced via the introduction of electricity or magnetic fields in the cartridge substrate 202 or stage. In at least one example, the force may comprise an adhesive, solder, or etc. Dislodging can take place when a microdevice 206 within a moving solution encounters a captured microdevice 206A. In at least one example, encounters may be direct contact between moving microdevice 206 and a captured microdevice 206A.

[0061] Referring again to Figures 4 A- 4E, as microdevices 206 start to fill location 204 in cartridge substrate 202, the suction force may be adjusted. In at least one example, as more vias 302 are plugged by microdevices 206A, fluid component 420 starts to diminish in reservoir 404. In at least one example, suction force generated by suction device 406 can be modulated as more microdevices 206A are trapped within locations 204. In at least one example, reduction in fluid flowing into and within reservoir 404 towards suction device 406 can be sensed and suction force can be modulated. In at least one example, suction force can be reduced as more vias are plugged. In at least one example, the suction force can remain with a same magnitude and more vortices may be formed near vias 302 of empty cartridges. In at least one example, a flow control mechanism within suction device 406 can be used to adjust the suction power through vias 302. In at least one example, sensors may be implemented within reservoirs to determine level of fluid component 420. In at least one example, extracted fluid component 420 can be sent back to housing through inlet 410 or through a different inlet within housing 408.

[0062] In at least one example, an artificial intelligence or machine learning model may control the fluid flow or suction force which may be modulated in response to sensor measurements. To dynamically adjust the suction force and fluid flow based on sensor data, artificial intelligence (Al) algorithms can be employed. In at least one example, reinforcement learning (RL) - Deep Q-Network (DQN) can be used. Reinforcement Learning (RL) may be well-suited for dynamically adjusting system parameters based on real-time feedback from sensors. A Deep Q- Network (DQN) can be trained to optimize suction force modulation by learning from past actions and their effects on fluid dynamics. The system treats the suction device as an agent that takes actions (modulating suction force). The environment provides a reward signal (e.g., optimized fluid flow, number of vias filled). Sensors measure fluid levels, flow rates, and vortex formation, feeding real-time data into the DQN. Over time, the model learns the optimal control strategy to maximize efficiency and minimize errors. In at least one example, the DQN could be trained using simulated fluid dynamics models before deployment in the real-world system.

[0063] In at least one example, recurrent neural network (RNN) - a long short-term memory (LSTM) can be used. Fluid dynamics and suction force changes are time-dependent processes. In at least one example, an LSTM model can predict how fluid levels and flow rates change over time, allowing proactive adjustments. The system can collect time-series data from sensors (fluid level, suction power, flow rate). In at least one example, the LSTM model can learnpaterns in the changes of these variables and predict future states, in at least one example, the predictions can help adjust the suction force preemptively, rather than reactively, to optimize performance. In at least one example, an LSTM network can be trained using historical data from system operations and CFD (computational fluid dynamics) simulations.

[0064] In at least one example, after a set level of locations 204 capture microdevices 206, a trimming process may be implemented (as described in association with Figure 1A). In at least one example, a trimming process may be implemented to remove any oddly positioned microdevices 206. In at least one example, to remove the oddly positioned microdevices, a force less than a force capturing microdevices 206A within microdevices 206 can be used. As described above, in at least one example, the suction force can be provided by a continual activation of suction device 406 In at least one example, microdevices 206 not positioned within locations 204 can be dislodged by agitation of a solution or by spraying fluid or gas on the cartridge substrate 202. In at least one example, spraying of a fluid or gas on the cartridge substrate 202 can be done after fluid portion of solution 416 is mostly removed. In at least one example, the gas can comprise dry, clean air, or nitrogen. In at least one example, fluid can include deionized water, alcohol, or other fluids that do not react with materials of microdevices 206 or cartridge substrate 202. In at least one example, the trimming process may comprise a traditional placement method such as a via a pick and place device to remove or adjust oddly positioned microdevices 206. In at least one example, the trimming process may be controlled at least in part by an artificial intelligence or machine learning model capable of identifying oddly positioned microdevices 206, selecting an action to remove or reposition a microdevice 206, and executing the action to remove the microdevice 206 or alter the position of the microdevice 206 in a location 204.

[0065] In at least one example, after an initial round of filling and trimming process, cartridge substrate 202 may be removed from apparatus 400 and inspected to determine how many microdevices 206 are captured in locations 204. In at least one example, the inspection may occur within the apparatus 400. The inspection may comprise analysis via an artificial intelligence or machine learning algorithm which may identify microdevices 206 properly captured in locations 204 and defects which may comprise empty locations 204 or oddly positioned microdevices 206. In at least one example, an Al-based defect inspection system for microdevice capture in cartridges can be implemented using computer vision and deep earningtechniques. In at least one such example, convolutional neural network (CNN)-based defect detection can be implemented. After the initial filling and trimming process, cartridge substrate 202 can be scanned using a high-resolution camera or an automated optical inspection (AOI) system. The imaging system can capture top-down and angled views of microdevices 206 inside locations 204. Images are preprocessed using edge detection (e.g., Canny filter) and contrast enhancement to clearly differentiate microdevices from cartridge substrate 202. In at least one example, a segmentation algorithm (e.g., U-Net or Watershed Algorithm) isolates microdevices from the background. In at least one example, a Convolutional Neural Network (CNN), trained on thousands of images of properly placed and defective microdevices, can classify each location 204 into categories, such as (1) properly captured, (2) empty cartridge, (3) misaligned microdevice, (4) partially inserted or tilted microdevice, or (5) defective microdevice. In at least one example, if too many defects are detected, the system can trigger a rework process, sending cartridge substrate 202 back for refilling. If defects are within acceptable limits, the system marks the defective areas for manual repair or removal. In at least one example, data can be stored for trend analysis, allowing process optimization to reduce defect rates over time. In at least one example, inspection can provide understanding of the number of iterations of filling and trimming that may be needed to reach a target level of microdevices 206 to be filled within locations 204. In at least one example, when cartridge substrate 202 is reinserted with microdevices 206A captured in locations 204, suction process is activated prior to flowing fluid to ensure that captured microdevices 206 are not removed. In alternate embodiments, other methods of securing captured microdevices 206 may be utilized, such as adhesive, solder, or physical interlocking structures. In at least one example, a subsequent filling operation may be performed with the same solution or a solution comprising a different density of microdevices 206. In at least one example, one or more iteration processes can be performed until a set number or percentage of locations 204 per cartridge substrate 202 are filled with microdevices 206, for example, at least 98%. In at least one example, to facilitate the iteration process, inspection of cartridge substrate 202 can be performed to ensure that fluid dispensed is of suitable quality such as if the fluid is being reused from a previous filling stage. In at least one example, a suitable fluid quality may comprise a viscosity within a specified range and particulate contamination less than a threshold value. In at least one example, cartridge substrate 202 is inspected for defectively positioned microdevices 206 that are subsequently removed bygas spray. In at least one example, repairing or repositioning of microdevices 206 may be done to fill the empty spots, fix the orientation, or replace the defective devices. In at least one example, repairing or repositioning of microdevices 206 may be achieved by a subsequent filling process within apparatus 400. In at least one example, the repairing or repositioning of microdevices 206 may be achieved using another device, such as a pick and place device. In at least one example, the process of repairing or repositioning microdevices may comprise a series of alternating filling and trimming processes which may be completed within apparatus 400 or which may occur in separate devices. In at least one example, after the density of microdevices 206A captured meets or exceeds a threshold number, and cartridge substrate 202 is filled with microdevices 206A, the process can be stopped to remove microdevices for further processing. In at least one example, when cartridge substrate 202 is filled with microdevices 206 as shown in Figure 2B, cartridge substrate 202 may be aligned with a system or a receiving substrate and microdevices 206 can be transferred into the system substrate. In at least one example, a suction force can be applied to a bottom surface of cartridge substrate 202 to facilitate transfer.

[0066] Figure 4F illustrates an example of a setup 400F to implement the embodiment in Figure 3A. In at least one example, setup 400F includes many features of apparatus 400 (Figure 4A). In at least one example, cartridge substrate 202 borders two environments, environment 424A and environment 424B. In at least one example, surface of environment 424A faces a solution 416 with dispersed microdevices 206, and surface of environment 424B faces an environment that facilitates the suction through via 302. In at least one example, suction device 406 can be added to control suction of fluid within via 302. In at least one example, the extracted fluid component of solution 416 can be sent back to the environment 424A. In at least one example, environment 424A, can have agitation sources 414, which can also be used to move solution 416. In at least one example, there can also be generic agitation that moves setup 400F. In at least one example, a flow control in suction device 406 can be used to adjust flow power of droplets 418 as more microdevices 206 are placed in the intended locations and block them through via 302.

[0067] Figure 5A illustrates a cross-sectional view of an electromagnetic apparatus 500 designed to create a magnetic field, in at least one example. In at least one example, electromagnetic apparatus 500 is designed to attract, using an electromagnetic force, a microdevice 206 within a substrate, such as cartridge substrate 202 (Figure 2A). In at least one example, electromagnetic apparatus 500 includes a cartridge substrate 502, and an electrodestructure 504 above cartridge substrate 502, and a current or voltage source 505 coupled with the electrode structure 504. In at least one example, electrode structure 504 comprises a pair of lateral electrodes 506, and a via electrode 508 coupled with each lateral electrode 506. In at least one example, lateral electrode 506 is above a buffer layer 510. In at least one example, buffer layer 510 can be a single layer or a plurality of layers of dielectric on cartridge substrate 502. In at least one example, buffer layer 510 includes silicon and at least one of oxygen, nitrogen, or carbon. In at least one example, lateral electrode 506 can be formed on buffer layer 510 by a dual damascene process or by deposition of a conductive material and be patterned. In at least one example, via electrode 508 may be formed on each lateral electrode 506. In at least one example, via electrode 508 may be formed within one or more layers of dielectric formed above buffer layer 510, for example dielectric 512. In at least one example, via electrode 508 may be formed by a dual damascene process in dielectric 512 or by deposition of a conductive material on lateral electrode 506 and be patterned. In at least one example, electrode 514 can be formed on via electrode 508.

[0068] In at least one example, a dielectric 516 can be formed on dielectric 512 and electrode 514 can be formed by a damascene process. In at least one example, material of electrode 514 can be deposited on dielectric 512 and on via electrode 508 and subsequently patterned. Electrode 514 is coupled with at least two via electrodes to form a continuous electrical conduit. Electrode 514 may be designed to create a lateral magnetic field in a plane that extends in the X- Y-axis. In at least one example, electrode 514 may be a plate electrode as illustrated in Figure 5B. In at least one example, electrode 514 may be wider than lateral electrode 506. In at least one example, plate electrode may be comparable in width to a width of lateral electrode 506, where the widths are measured along Y-axis direction. In at least one example, electrode 514 may comprise lateral wires 514A as illustrated in Figure 5C. In at least one example, lateral wires 514A may produce a uniform lateral magnetic field in a plane that extends in the X-Y axis.

[0069] Figure 5D shows an example of a setup 500D to implement the embodiment in Figure 2A based on an electrostatic or an electromagnetic force. In at least one example, set up 500D can include a buffer layer 520 on a cartridge substrate 522. An electrode 524 is deposited on the buffer layer (or substrate). In at least one example, a dielectric 530 covers electrode 524. In at least one example, electrode 524 is connected to a force electrode 526 through a via 528. A voltage or current is applied to the force electrode 526 through the electrode 524. If a current isapplied, two vias 528 can be connected to force electrode 526 to facilitate a current path. In at least one example, current can generate electromagnetic force to attract the microdevices where microdevices may have magnetic materials on one surface. In the case of electrostatic force, voltage is applied to force electrode 526, and a dielectric covers force electrode 526.

[0070] Figure 6 A is an isometric illustration of an enhanced portion of a cartridge integrated with the electrode structure, in at least one example. In at least one example, an outline of electrode 514 is illustrated in dashed lines. In at least one example, plate electrode 514 may have a plan-view cross sectional area that is comparable to plan-view cross sectional area of location 204. In at least one such example, magnetic field generated by electromagnetic apparatus 500 may penetrate via 302 and cartridge substrate 202. In at least one example, electrode 514 may have a plan-view cross sectional area that can be tuned. In at least one example, electrode 514 may have a plan- view cross sectional area that is comparable to size of via 302. In at least one example, magnetic fields may penetrate through via 302. In at least one example, a smaller planview cross sectional area of electrode 514 may produce a smaller stray magnetic field that can attract more than one memory device.

[0071] Figure 6B illustrates a cross section of structure in Figure 6A, through a line A-A’, in at least one example. In at least one example, electrode structure 504 is positioned directly below cartridge substrate 202. In at least one example, 202 may be in contact with dielectric 516. In at least one example, depth Dvof via 302 may be adjusted depending on peak electromagnetic field generated. In at least one example, size of via 302 may be increase compared to size of via 302 within cartridge in Figure 2A. In at least one example, while fluid will enter via 302 during operation, via 302 is not a through via for fluid to transfer to a reservoir below (as discussed below). In at least one example, a lateral magnetic field (along X-Y plane) may be generated by electrode 514 during operation.

[0072] In at least one example, a microdevice 602 is inserted to illustrate how microdevice 602 may be positioned in location 204. In at least one example, microdevice 602 includes a magnet 604 at a base portion of microdevice 602. In at least one example, magnet 604 may be a permanent magnet, such as a permanent magnet having a weak magnetic coercivity. In at least one such example, the permanent magnet can include one or more layers of magnetic material. In at least one example, the layers range in thickness between 100 nm and 1 micron. In at least one example, the lateral extent of magnet 604 may be an order of magnitude smaller than alateral thickness of microdevice 602 to prevent interaction between different microdevices 602. A permanent magnet with weak magnetic coercivity can retain magnetization but can be influenced by external fields. In at least one example, a permanent magnet can include one or more layers of magnetic material, for example, nickel (Ni), cobalt (Co), iron (Fe), or rare-earth compounds (SmCo, NdFeB, etc.). In at least one example, thickness of the magnetic layers can be between 100 nm to 1 pm. In at least one example, a thin-film deposition technique such as sputtering or electron beam evaporation may be used to form magnets with thicknesses in the range of 100 nm to 1 pm.

[0073] In at least one example, the lateral size of the magnet 604 can be an order of magnitude smaller than the lateral thickness of microdevice 602. In at least one such example, a microdevice 602 that is approximately 50 pm in thickness, can have a magnet 604 with a lateral dimension of approximately 5 pm or smaller to avoid interactions between neighboring microdevices while being suspended in the fluid. The magnetic field strength (H) and flux density (B) of magnet 604 can depend on functionality. Magnet 604 should have sufficient strength to keep microdevice 206 in place within location 204 but weak enough to prevent interference with magnets 604 in other microdevices 206. In at least one example, magnetic field strength (H) and flux density (B) can also depend on material properties, such as a soft magnetic material (low coercivity) with H approximately equal to 10-100 Oersteds (Oe) or hard magnetic materials (high coercivity) with H approximately equal to 1,000-10,000 Oe. A weak permanent magnet might have a remanent magnetic field strength (BR) of 100 mT to 500 mT (0.1-0.5 Tesla). In at least one example, if a lateral thickness of magnet 604 is small (e.g., 5 pm or less), stray magnetic field from magnet 604 can decay within a perimeter of microdevice 206, limiting interactions between individual microdevices 206. In at least one example, magnet 604 can have a surface magnetic flux density (B) in a range of 50 mT to 500 mT (0.05 T - 0.5 T) and a coercivity (He) in a range of 50 Oe to 500 Oe, to allow weak but stable magnetization. In at least one example, the magnet 604 may comprise a north-south orientation that may be directed along the Z-axis direction.

[0074] Figure 6C is a plan-view illustration of a microdevice 602 including a magnet 604, in at least one example. In at least one example, magnet 604 is oriented with a north-south (N-S) field along a Y-axis, where the north to south pole vector is directed towards a negative Y- axis direction. In at least one example, when electrode 514 carries a current travelling in a positiveX-axis direction, magnet 604 (and the microdevice 206) experiences a force in a negative Z-axis direction (or into the plane of the figure). Referring again to Figure 6B, the magnetic force forces microdevice 206 to be attracted to electrode 514.

[0075] Figure 7A illustrates an apparatus 700 including electromagnetic apparatus 500 in Figure 5A designed to attract suspended microdevices in a fluid, in at least one example. In at least one example, electromagnetic apparatus 500 comprises a series of electrode structures 504 coupled in series. In at least one example, each electrode structure 504 is coupled by a conductor 701. In at least one example, conductor 701 may be replaced by a single lateral electrode 506 shared between two adjacent electrode structures 504. In at least one such example, one lateral electrode 506 couples two via electrodes 508, where two via electrodes 508 are coupled with two different electrodes 514. In at least one example, electromagnetic apparatus 500 is coupled with a voltag e / current source 702, where voltage / current source 702 is coupled to two terminals, terminal A and terminal B of electromagnetic apparatus 500. In at least one example, voltage / current source 702 can drive a current through electrode 514 of each electrode structure 504 as will be discussed below.

[0076] In at least one example, cartridge substrate 202, comprising locations 204 and vias 302, is positioned above electromagnetic apparatus 500. In at least one example, each location 204 is positioned above a single electrode structure 504. In at least one example, electrode 514 of each electrode structure 504 is aligned with or substantially aligned with via 302.

[0077] In at least one example, apparatus 700 includes a pump 704 coupled with outlet 412 of housing 408. In at least one example, cartridge substrate 202 is in contact with electromagnetic apparatus 500 and creates a seal to prevent fluid to extend past via 302. In at least one example, via 302 can comprise a plurality of smaller vias that constrict fluid flow but enable field lines and electromagnetic interaction between electrode structure 504 and permanent magnet within microdevices 206 during operation. In at least one example, an additional material may be present between cartridge substrate 202 and electromagnetic apparatus 500 to create a seal. In at least one such example, the material is capable of transmitting flux lines and does not include a flux excluding or magnetic shielding material.

[0078] Figure 7B illustrates apparatus 700 in Figure 7A demonstrating a process to flow a fluid comprising suspended microdevices 206 over an energized electromagnetic apparatus 500 and attracting microdevices 602 within locations 204, in at least one example. In at least oneexample, solution 416 enters housing 408 through inlet 410. In at least one example, pump 704 is activated and solution flows along the X-axis direction in housing 408 towards outlet 412. In at least one example, the properties of solution 706 may include properties of solution 416 described above (Figure 4B), for example, solution 416 comprises microdevices 602 suspended in a fluid. In at least one example, number density of microdevices 602 per unit of fluid volume may be the same as solution 416. In at least one example, as solution 706 flows, electromagnetic apparatus 500 is energized. In at least one example, solution 706 may start flowing into housing 408 at a same time as electromagnetic apparatus 500 is energized. In at least one example, electromagnetic apparatus 500 is energized by application of a voltage between terminal A and terminal B, causing a current 708 to flow along a positive X-axis direction within each electrode 514. In at least one example, the voltage is a DC voltage and current 708 is a DC current. In at least one example, as solution 706 flows, some microdevices 602 suspended in the fluid move over locations 204 experience a magnetic force as described in Figure 6C.

[0079] Referring collectively to Figure 6C and Figure 7B, in at least one example, interaction between current 708 and magnetic field of the permanent magnetic within microdevice 602 causes a force on the magnet in a negative Z-axis direction. In at least one example, this force causes magnet 604 (and microdevice 602) to move and be confined by location 204. In at least one example, current flowing through electrode 514 creates a magnetic field in the vicinity of location 204. In at least one example, magnetic field generated by magnet 604 is along a same direction as the magnetic field created by current 708 traversing in electrode 514. In at least one example, these two fields align themselves and aid in microdevice 602 to be captured with a correct orientation within location 204.

[0080] In at least one example, when magnet 604 within microdevice 602 has an orientation along the negative Y-axis direction, magnet 604 (and microdevice 602) can change orientation to align with the field generated by current 708 flowing through electrode 514. In at least one example, the alignment also causes microdevice 602 to be positioned with a proper orientation within location 204. In at least one such example, two or more microdevices 602 that are oppositely directed can repel each other in the presence of electrode 514. In at least one example, repulsion between two microdevices 602 can be useful to capture a single microdevice 602 with location 204. In at least one example, magnetic fields may be pulsed and / or oscillated to selectively move microdevices 602. The pulsed or oscillated magnetic fields may becontrolled via artificial intelligence or machine learning algorithms which may use sensor data from imagery to track the position and orientation of each microdevice 602. In at least one example, varying magnetic fields prevent microdevices 602 from being attracted to each other. Movement or agitation of the solution may further aid alignment and positioning of the microdevices 602. In at least one example, agitator 414A and agitator 414B can be activated while solution 706 is flowing within housing 408. In at least one example, agitator 414A and agitator 414B can also help to move solution 706. In at least one example, apparatus 700 can be on a stage that can be mechanically agitated. In at least one example, apparatus 700 can be on a stage that can be mechanically agitated in addition to implementing agitator 414A and agitator 414B. Examples of agitation may include vibration, rotation, or changes in vertical alignment or pitch of the stage.

[0081] In at least one example, the methods of trimming, examining, and transferring microdevice 602 within cartridge substrate 202 are the same or substantially the same as discussed above (Figure 4B). In at least one example, solution 706 entering inlet 410 can be halted and solution 706 within housing 408 can be pumped away. In at least one example, pump 704 can recirculate solution 706 by directing it into a reservoir that is an original source of solution 706 that is fed into inlet 410. In at least one example, after pump 704 removes all solution from cartridge substrate 202, cartridge substrate 202 can be examined for number of microdevices 602 captured and a process described above can be utilized to remove improperly positioned microdevices that may have settled on surface of cartridge substrate 202. In at least one example, a gas or a fluid spray can be used to loosen and remove improperly positioned microdevices 602. In at least one example, cartridge substrate 202 and electromagnetic apparatus 500 can be removed together from apparatus 700. In at least one example, by application of current 708, already captured microdevices 602 may be held within locations 204. In at least one example, cartridge substrate 202 can be reintroduced into housing 408 and the process of solution flow, removing improperly positioned microdevices 602 and examination of cartridge substrate 202 can be repeated until a set number density of properly positioned microdevices 602 within locations 204 is reached.

[0082] In at least one example, when driving mechanism for capture includes an electrostatic force, voltage is applied to the force electrode, and a dielectric covers the force electrode. This creates a negative electrostatic charge which is capable of attracting microdevices 602 if they arefirst given a positive charge. Modulating the applied voltage and providing a flow of fluid, such as a liquid solution or gas across the cartridge substrate 202 allows microdevices 602, which have settled into locations 204, to remain while those in solution flow freely across the substrate.

[0083] Figure 8 shows a setup 800 that uses setup 500D in Figure 5D and to microdevices 206 from solution 804. In at least one example, setup 800 includes many of the features of apparatus 700 (Figure 7A). In at least one example, cartridge substrate 802 faces the solution environment 808. In at least one example, the surface faces a solution 804 with dispersed microdevices 206, and a second surface faces an exterior environment. In at least one example, voltage or current source 822 biases electrode connected to the force electrodes within array 810. In at least one example, array 810 includes features of setup 500D (Figure 5D). In at least one example, a solution environment 808 can have agitation sources 820, which can move the solution 804. There can also be a generic agitation that at least laterally or vertically moves setup 800.

[0084] In some instances, well-known methods and devices are shown in block diagram form, rather than in detail, to avoid obscuring at least one example. Reference throughout this specification to “an example,” “one example,” “in at least one example,” or “some examples” means that a particular feature, structure, function, or characteristic described in connection with example is included in at least one example. Thus, appearances of phrase “in an example,” “in at least one example,” “in one example,” or “some examples” in various places throughout this specification are not necessarily referring to same example of disclosure. Furthermore, particular features, structures, functions, or characteristics may be combined in any suitable manner in one or more examples. For example, a first example may be combined with a second example anywhere particular features, structures, functions, or characteristics associated with two examples are not mutually exclusive.

[0085] As used in herein, singular forms “a,” “an,” and “the” are intended to include plural forms as well, unless context clearly indicates otherwise. It will also be understood that term “and / or” as used herein refers to and encompasses all possible combinations of one or more of associated listed items.

[0086] Here, “coupled” and “connected,” along with their derivatives, may be used herein to describe functional or structural relationships between components. These terms are not intended as synonyms for each other. Rather, in particular examples, “connected” may be used to indicate that two or more elements are in direct physical, optical, or electrical contact witheach other. “Coupled” may be used to indicated that two or more elements are in either direct or indirect (with other intervening elements between them) physical, electrical, or in magnetic contact with each other, and / or that two or more elements co-operate or interact with each other (e.g., as in a cause an effect relationship).

[0087] Here, “over,” “under,” “between,” and “on” as used herein refer to a relative position of one component or material with respect to other components or materials where such physical relationships are noteworthy. For example, in context of materials, one material or material disposed over or under another may be directly in contact or may have one or more intervening materials. Moreover, one material disposed between two materials may be directly in contact with two layers or may have one or more intervening layers. In contrast, a first material “on” a second material is in direct contact with that second mater ial / material. Similar distinctions are to be made in context of component assemblies. As used throughout this description, and in claims, a list of items joined by term “at least one of’ or “one or more of’ can mean any combination of listed terms.

[0088] Here, “adjacent” generally refers to a position of a thing being next to (e.g., immediately next to or close to with one or more things between them) or adjoining another thing (e.g., abutting it).

[0089] Here, “signal” may refer to current signal, voltage signal, magnetic signal, or data / clock signal.

[0090] Here, “device” may generally refer to an apparatus according to context of usage of that term. For example, a device may refer to a stack of layers or structures, a single structure or layer, a connection of various structures having active and / or passive elements. Generally, a device is a three-dimensional structure with a plane along x-y direction and a height along z direction of an x-y-z Cartesian coordinate system. In at least one example, plane of device may also be plane of an apparatus which comprises device.

[0091] Unless otherwise specified in explicit context of their use, terms “substantially equal,” “about equal,” and “approximately equal” mean that there is no more than incidental variation between two things so described. Such variation is typically no more than + / -10% of a predetermined target value.

[0092] Here, “left,” “right,” “front,” “back,” “top,” “bottom,” “over,” “under,” and similar terms are used for descriptive purposes and not necessarily for describing permanent relative positions.For example, terms “over,” “under,” “front side,” “back side,” “top,” “bottom,” “over,” “under,” and “on” as used herein refer to a relative position of one component, structure, or material with respect to other referenced components, structures, or materials within a device, where such physical relationships are noteworthy. These terms are employed herein for descriptive purposes only and predominantly within the context of a device z-axis and therefore may be relative to an orientation of a device. Hence, a first material “over” a second material in context of a figure provided herein may also be “under” second material if the device is oriented upside-down relative to context of figure provided. Similar distinctions are to be made in the context of component assemblies.

[0093] Here, “between” may be employed in context of z-axis, x-axis, or y-axis of a device. A material that is between two other materials may be in contact with one or both of those materials. In another example, a material that is between two or other materials may be separated from both of other two materials by one or more intervening materials. A material “between” two other materials may therefore be in contact with either of other two materials. In another example, a material “between” two other materials may be coupled to other two materials through an intervening material. A device that is between two other devices may be directly connected to one or both of those devices. In another example, a device that is between two other devices may be separated from both of the other two devices by one or more intervening devices.

[0094] While examples and applications of the present disclosure have been illustrated and described, it is to be understood that the disclosure is not limited to the precise construction and compositions disclosed herein and that various modifications, changes, and variations can be apparent from the foregoing descriptions without departing from the spirit and scope of the disclosure as defined in the appended claims.

Claims

CLAIMSWhat is claimed is:

1. A method to populate a cartridge substrate within an apparatus, the method comprising: providing the cartridge substrate comprising a plurality of locations; dispersing a solution comprising a plurality of microdevices; flowing the solution over a surface of the cartridge substrate; collecting an individual microdevice within the plurality of microdevices in an individual location within the plurality of locations by enabling the individual location to accept the individual microdevice; and filling the plurality of locations with the plurality of microdevices.

2. The method of claim 1, wherein the plurality of microdevices are dispersed in the solution by sonication or dispersion agents.

3. The method of claim 1, wherein the apparatus further comprises: an inlet and outlet for controlling flow of the solution over the cartridge substrate; a suction mechanism coupled to the apparatus; and a control system that adjusts suction force in response to sensor data monitoring flow of the solution.

4. The method of claim 3, wherein the individual location comprises a via opening, wherein the suction force through the via opening causes the individual microdevice to be attracted to the individual location and facilitates positioning of the individual microdevice.

5. The method of claim 3, wherein the suction force is utilized to hold a microdevice into a location once the microdevice is captured.

6. The method of claim 1 , wherein the individual location has dimensions that are greater than dimensions of the individual microdevice.

7. The method of claim 1, wherein after the plurality of locations are filled with the plurality of microdevices, a filing process is halted and the cartridge substrate is removed to transfer captured microdevices.

8. The method of claim 7, wherein the plurality of locations are inspected to determine if all locations are filled with microdevices and that there are no tilted or incorrectly oriented microdevices.

9. The method of claim 7, wherein repair process is performed to fill at least one individual location that is empty, fix orientation of at least one first individual microdevice that is captured, or replace at least one second individual microdevice that is defective.

10. The method of claim 7, wherein the plurality of locations are aligned with a system cartridge substrate, and wherein the plurality of microdevices within the plurality of locations are transferred into the system cartridge substrate.

11. The method of claim 7, wherein the apparatus further comprises an agitator, wherein the agitator comprises a pump, a paddle, a source of pressurized gas, a source of a second fluid, or a sonicator, and wherein the agitator is implemented to stir the solution to move the plurality of microdevices.

12. The method of claim 6, wherein the apparatus further comprises a stage, wherein the stage is utilized to move the cartridge substrate.

13. A method for positioning microdevices on a cartridge substrate, comprising: providing the cartridge substrate with a plurality of locations; dispensing a fluid comprising the microdevices over the cartridge substrate; capturing the microdevices within the plurality of locations using a controlled force; removing misaligned or excess microdevices via a trimming process; and inspecting the cartridge substrate to determine placement accuracy of the microdevices.

14. A system for guiding microdevices into locations, comprising: a cartridge substrate with the locations and fluid regions; a housing including an inlet and outlet for controlled fluid flow, wherein the cartridge substrate is positioned in the housing; a suction mechanism operatively coupled to the cartridge substrate to facilitate microdevice positioning; and a control system that adjusts suction force in response to sensor data monitoring fluid flow and microdevice placement.

15. A method for inspecting and correcting microdevice placement, comprising: capturing images of microdevice positions using an imaging system; analyzing the images via an artificial intelligence model to classify defects; identifying and marking locations with missing, misaligned, or defective microdevices; and initiating corrective actions to reposition, remove, or replace microdevices.

16. A method for iterative microdevice placement, comprising: dispensing a solution containing microdevices over a cartridge substrate; capturing the microdevices within locations in the cartridge substrate; performing a trimming operation to remove excess or misaligned microdevices; inspecting the cartridge substrate to determine a fill percentage; and repeating the dispensing and the trimming operation until a predefined fill percentage is reached.

17. A system for optimizing microdevice placement using Al-driven fluid dynamics, comprising: a fluid dispensing system configured to direct microdevices toward a cartridge substrate; a set of sensors monitoring fluid flow and microdevice distribution; an artificial intelligence model analyzing real-time sensor data; anda control unit dynamically adjusting fluid flow parameters based on Al-driven optimization.

18. A system for electromagnetic-assisted positioning of microdevices, comprising: a cartridge substrate comprising locations for receiving the microdevices; an electrode array positioned beneath the cartridge substrate; a power source operatively coupled to the electrode array to generate an electromagnetic field; and a control module configured to regulate the electromagnetic field for guiding and securing the microdevices in the locations.

19. A method to populate a cartridge substrate, the method comprising: providing an apparatus comprising: an electrode array positioned beneath the cartridge substrate; a power source operatively coupled to the electrode array to generate an electromagnetic field; and a control module configured to regulate the electromagnetic field; positioning cartridge substrate comprising a plurality of locations within the apparatus; providing a solution comprising a plurality of microdevices, wherein individual microdevices in the plurality of microdevices comprise a magnet; flowing the solution over a surface of the cartridge substrate; collecting an individual microdevice within the plurality of microdevices in an individual location within the plurality of locations by electromagnetically attracting the plurality of microdevices; and filling the plurality of locations with the plurality of microdevices.

20. The method of claim 19, wherein the electrode array comprises an electrode oriented parallel to a direction of flow of solution.

21. The method of claim 19, wherein the magnet is a weak permanent magnet and wherein the weak permanent magnet comprises a magnetic field strength (H) in a range between 10-100 Oersteds (Oe).

22. The method of claim 19, wherein the magnet is a strong permanent magnet and wherein the strong permanent magnet comprises a magnetic field strength (H) in a range between 1,000-10,000 Oe.

23. The method of claim 19, wherein the magnet comprises a north to south orientation that is orthogonal to a direction of flow of the solution.

24. The method of claim 21, wherein when the power source is operated, a direct current (DC current) flows in the electrode array along a direction parallel to the direction of flow of the solution, and wherein an interaction between the DC current and a magnetic field of the weak permanent magnet creates a magnetic force directed towards the individual location.

25. The method of claim 24, wherein the DC current flows along a positive X-axis direction and wherein the magnet is oriented with a north-south (N-S) field along a Y-axis, where a vector extending from north to south pole is directed towards a negative Y-axis direction.

26. The method of claim 22, wherein when the power source is operated, a direct current (DC current) flows in the electrode array along a direction parallel to the direction of flow of the solution, and wherein an interaction between the DC current and a magnetic field of the strong permanent magnet creates a magnetic force directed towards the individual location.

27. The method of claim 26, wherein the DC current flows along a positive X-axis direction and wherein the magnet is oriented with a north-south (N-S) field along a Y-axis, where a vector extending from north to south pole is directed towards a negative Y-axis direction.

28. A method for system for electromagnetic-assisted positioning of microdevices, comprising: a cartridge substrate comprising locations for receiving the microdevices; an electrode array positioned beneath the cartridge substrate; a power source operatively coupled to the electrode array to generate an electromagnetic field; and a control module configured to regulate the electromagnetic field for guiding and securing the microdevices in the locations.

29. A system for electrostatic-assisted positioning of microdevices, comprising: a cartridge substrate comprising locations with embedded electrically conductive elements; a voltage source operatively coupled to the embedded electrically conductive elements to generate an electrostatic field; a capture mechanism using electrostatic attraction; and a control system configured to selectively release the microdevices by modulating an applied voltage generated from the voltage source.

30. A system for transferring microdevices from a donor cartridge substrate to a receiving cartridge substrate, comprising: the donor cartridge substrate containing the microdevices with embedded magnets; the receiving cartridge substrate with an electromagnetic positioning system; and a control system configured to generate and adjust electromagnetic fields to attract and transfer the microdevices while maintaining alignment.

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